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analyst75

Factors that determine money doubling scams – Confidential

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The 419 plan is that you send money to get 100% profits of what you send in less than 50 minutes.

 

They ask you to send more money once you send first amount.

 

They don’t have any website. Even if they do, they can pull it down.

 

They have no physical office.

 

They claim you cannot comment cause of spamming, but they often remove members (who can’t comment). Needless to say, those members have been scammed or realized they’re criminals and instead, they think his presence in the group is no longer needed.

 

They appear religious.

 

They use multiple phone numbers belonging to part of their groups to give fake testimony, to deceive people. Alerts shown are money from fools who send money to them. They’re not from investors who get paid.

 

You join them or they add you.

 

People should start massive campaigns against these idiots who come in different investment names.

 

The public should be warned.

 

 

TO REITERATE

 

This is a scam. They have duped many people.... Promising to double their money everyday.

 

If this was possible, every Nigerian would be rich.

 

They are smart liars and a group of fraudsters, who will do everything possible to convince you they're genuine and God-fearing.

 

Once they collect your money, they remove you from their group. You can't even comment so that others won't know they're criminals.

 

Those who share fake testimonies are part of a large group of the scammers... And they're the ones that can post.. In order to deceive people that this is real.

 

The alerts they show you are actually alerts of funds sent by their victims (mumus/magas, who want to become rich by having their monies doubled).

 

They're now targeting WhatsApp, Telegram, Facebook and Instagram, looking for victims to join them. The go as far as hacking social media accounts so that they can deceive and lure your friends and family by posting the scam business, as if you had tried and trusted them (thus ruining your reputation). Now ask yourself, would a legitimate business hack people’s accounts so that they can get more clients?

 

Would they add you to their groups without your consent?

 

 They have no websites and no offices...  Sometimes, their written English is terrible. Even if they do, they can always pull the websites and move offices and remove their SIMs.

 

You can only PM the admin that will eventually block you once they succeed in stealing your money.

 

And they are desperately looking for more victims.

 

Please run for your life.

 

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Just now, mitsubishi said:

So when are you gonna get started? this sounds right up your street

 

On 11/27/2019 at 9:49 AM, analyst75 said:

The 419 plan is that you send money to get 100% profits of what you send in less than 50 minutes.

 

They ask you to send more money once you send first amount.

 

They don’t have any website. Even if they do, they can pull it down.

 

They have no physical office.

 

They claim you cannot comment cause of spamming, but they often remove members (who can’t comment). Needless to say, those members have been scammed or realized they’re criminals and instead, they think his presence in the group is no longer needed.

 

They appear religious.

 

They use multiple phone numbers belonging to part of their groups to give fake testimony, to deceive people. Alerts shown are money from fools who send money to them. They’re not from investors who get paid.

 

You join them or they add you.

 

People should start massive campaigns against these idiots who come in different investment names.

 

The public should be warned.

 

 

TO REITERATE

 

This is a scam. They have duped many people.... Promising to double their money everyday.

 

If this was possible, every Nigerian would be rich.

 

They are smart liars and a group of fraudsters, who will do everything possible to convince you they're genuine and God-fearing.

 

Once they collect your money, they remove you from their group. You can't even comment so that others won't know they're criminals.

 

Those who share fake testimonies are part of a large group of the scammers... And they're the ones that can post.. In order to deceive people that this is real.

 

The alerts they show you are actually alerts of funds sent by their victims (mumus/magas, who want to become rich by having their monies doubled).

 

They're now targeting WhatsApp, Telegram, Facebook and Instagram, looking for victims to join them. The go as far as hacking social media accounts so that they can deceive and lure your friends and family by posting the scam business, as if you had tried and trusted them (thus ruining your reputation). Now ask yourself, would a legitimate business hack people’s accounts so that they can get more clients?

 

Would they add you to their groups without your consent?

 

 They have no websites and no offices...  Sometimes, their written English is terrible. Even if they do, they can always pull the websites and move offices and remove their SIMs.

 

You can only PM the admin that will eventually block you once they succeed in stealing your money.

 

And they are desperately looking for more victims.

 

Please run for your life.

 

Sounds like you're part of it Scamming is part of your CV you have publically and repeatedly admitted that and everybody knows you're a low life

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you and your mates invented this

Nigerian Letter or “419” Fraud

Nigerian letter frauds combine the threat of impersonation fraud with a variation of an advance fee scheme in which a letter mailed, or e-mailed, from Nigeria offers the recipient the “opportunity” to share in a percentage of millions of dollars that the author—a self-proclaimed government official—is trying to transfer illegally out of Nigeria. The recipient is encouraged to send information to the author, such as blank letterhead stationery, bank name and account numbers, and other identifying information using a fax number given in the letter or return e-mail address provided in the message. The scheme relies on convincing a willing victim, who has demonstrated a “propensity for larceny” by responding to the invitation, to send money to the author of the letter in Nigeria in several installments of increasing amounts for a variety of reasons. 

Payment of taxes, bribes to government officials, and legal fees are often described in great detail with the promise that all expenses will be reimbursed as soon as the funds are spirited out of Nigeria. In actuality, the millions of dollars do not exist, and the victim eventually ends up with nothing but loss. Once the victim stops sending money, the perpetrators have been known to use the personal information and checks that they received to impersonate the victim, draining bank accounts and credit card balances. While such an invitation impresses most law-abiding citizens as a laughable hoax, millions of dollars in losses are caused by these schemes annually. Some victims have been lured to Nigeria, where they have been imprisoned against their will along with losing large sums of money. The Nigerian government is not sympathetic to victims of these schemes, since the victim actually conspires to remove funds from Nigeria in a manner that is contrary to Nigerian law. The schemes themselves violate section 419 of the Nigerian criminal code, hence the label “419 fraud.”

Tips for Avoiding Nigerian Letter or “419” Fraud:

  • If you receive a letter or e-mail from Nigeria asking you to send personal or banking information, do not reply in any manner. Send the letter or message to the U.S. Secret Service, your local FBI office, or the U.S. Postal Inspection Service. You can also register a complaint with the Federal Trade Commission’s Complaint Assistant.
  • If you know someone who is corresponding in one of these schemes, encourage that person to contact the FBI or the U.S. Secret Service as soon as possible.
  • Be skeptical of individuals representing themselves as Nigerian or foreign government officials asking for your help in placing large sums of money in overseas bank accounts.
  • Do not believe the promise of large sums of money for your cooperation.
  • Guard your account information carefully.
Edited by mitsubishi

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2 minutes ago, mitsubishi said:

you and your mates invented this

Nigerian Letter or “419” Fraud

Nigerian letter frauds combine the threat of impersonation fraud with a variation of an advance fee scheme in which a letter mailed, or e-mailed, from Nigeria offers the recipient the “opportunity” to share in a percentage of millions of dollars that the author—a self-proclaimed government official—is trying to transfer illegally out of Nigeria. The recipient is encouraged to send information to the author, such as blank letterhead stationery, bank name and account numbers, and other identifying information using a fax number given in the letter or return e-mail address provided in the message. The scheme relies on convincing a willing victim, who has demonstrated a “propensity for larceny” by responding to the invitation, to send money to the author of the letter in Nigeria in several installments of increasing amounts for a variety of reasons. 

Payment of taxes, bribes to government officials, and legal fees are often described in great detail with the promise that all expenses will be reimbursed as soon as the funds are spirited out of Nigeria. In actuality, the millions of dollars do not exist, and the victim eventually ends up with nothing but loss. Once the victim stops sending money, the perpetrators have been known to use the personal information and checks that they received to impersonate the victim, draining bank accounts and credit card balances. While such an invitation impresses most law-abiding citizens as a laughable hoax, millions of dollars in losses are caused by these schemes annually. Some victims have been lured to Nigeria, where they have been imprisoned against their will along with losing large sums of money. The Nigerian government is not sympathetic to victims of these schemes, since the victim actually conspires to remove funds from Nigeria in a manner that is contrary to Nigerian law. The schemes themselves violate section 419 of the Nigerian criminal code, hence the label “419 fraud.”

Tips for Avoiding Nigerian Letter or “419” Fraud:

  • If you receive a letter or e-mail from Nigeria asking you to send personal or banking information, do not reply in any manner. Send the letter or message to the U.S. Secret Service, your local FBI office, or the U.S. Postal Inspection Service. You can also register a complaint with the Federal Trade Commission’s Complaint Assistant.
  • If you know someone who is corresponding in one of these schemes, encourage that person to contact the FBI or the U.S. Secret Service as soon as possible.
  • Be skeptical of individuals representing themselves as Nigerian or foreign government officials asking for your help in placing large sums of money in overseas bank accounts.
  • Do not believe the promise of large sums of money for your cooperation.
  • Guard your account information carefully.

once a scammer always a scammer.

once a rude pig to a customer always a rude pig to customers and we are never going to go away and forget it

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THE HISTORY OF BRICK WALLs

I will see if I can find something about bangng your head on one..hang on😀😝😀😩😦😚🤣😄🤯🤑😝😄😂😁

Man has used brick for building purpose for thousands of years. Bricks date back to 7000 BC, which makes them one of the oldest known building materials. They were discovered in southern Turkey at the site of an ancient settlement around the city of Jericho. 

The first bricks, made in areas with warm climates, were mud bricks dried in the sun for hardening. 
Ancient Egyptian bricks were made of clay mixed with straw. The evidence of this can be seen today at ruins of Harappa Buhen and Mohenjo-daro. Paintings on the tomb walls of Thebes portray Egyptian slaves mixing, tempering and carrying clay for the sun dried bricks. 

The greatest breakthrough came with the invention of fired brick in about 3,500 Bc. From this moment on, bricks could be made without the heat of sun and soon became popular in cooler climates. 

The Romans prefered to make their bricks in spring, then they stored them for two years before selling or using them. They only used white or red clay to manufacture bricks. 
The Romans succeeded in introducing fired bricks to the entire country thanks to mobile kilns. These were bricks stamped with the mark of the legion who supervised the brick production. Roman bricks differed in size and shape from other ancient bricks as they were more commonly round, square, oblong, triangular and rectangular. The kiln fired bricks measured 1 or 2 Roman feet by 1 Roman foot, and sometimes up to 3 Roman feet with larger ones. The Romans used brick for public and private buildings over the entire Roman empire. They built walls, forts, cultural centre, vaults, arches and faces of their aqueducts. The Herculaneum gate of Pompeii  and the baths of Caracalla in Rome  are examples of Roman brick structures.

 

 

During the period of the Roman Empire, the Romans spread the art of brickmaking throughout Europe and it continued to dominate during the medieval and Renaissance period.

When the Roman Empire fell, the art of brickmaking nearly vanished and it continued only in Italy and the Bizantine Empire. In the 11th century, brickmaking spread from these regions to France. 

 

During the 12th century bricks were reintroduced to northern Germany from northern Italy. This created the brick gothic period with buildings mainly built from fired red clay bricks. The examples of the Brick Gothic style buildings can be found in the Baltic countries such as Sweden, Denmark, Poland, Germany, Finland, Lithuania, Latvia, Estonia, Belarus and Russia. This period lacks in figural architectural sculptures which had previously been carved from stone. The Gothic figures were virtually impossible to create out of bricks at that time, but could be identified by the use of split courses of bricks in varying colours, red bricks, glazed bricks and white lime plaster. Eventually custom built and shaped bricks were introduced which could imitate the architectural sculptures. In the 16th century, Brick Gothic was replaced by Brick Renaissance architecture.    

In medieval times, the clay for making bricks often was kneaded by workers with their bare feet. They clay was shaped into brick by pushing it into a wooden frame placed on a table, which was covered with sand or straw to prevent the clay from sticking. After excess clay was wiped off with a stick, the brick was removed from the frame. 

In England the remains of buildings prove that the art of brickmaking was highly advanced by the time of Henry VIII. After the great fire of London in 1666, the city was rebuilt with mainly bricks. 

 

Adobe brick, which is sundried brick made of clay and straw, has been made for centuries in Central America, particularly in Mexico. Some Aztec adobe structures still exist, one example is the Pyramid of the Sun, built in the 15th century.

 

 

Bricks crossed the Atlantic with Dutch and British immigrants with some brickmasons among them. In Virginia brick structures were built as early as 1611. At that time it was common for brickmasons to make the bricks on the jobsite. It is known that bricks were transported from Virginia to Bermuda in 1621 in exchange for food and oil. 

Many early American skyscrapers are clad in brick or terracotta. It took 10 million bricks to build the Empire State Building. 

During the Renaissance and Baroque periods, exposed brick walls became less and less popular, consequently brickwork was covered in plaster. Only during the mid 18th century brick walls started to regain their popularity. 

 

Bricks were made by hand until about 1885. Once the Industrial Revolution broke out, the brickmaking machinery was introduced. Consequently, the number of clays that could be made into brick was greatly increased which influenced the production capacity. Handmade brick production ranged up to 36,000 bricks per week but by 1925 a brickmaking machine made 12,000 bricks a day. 

As brick structures could be built much quicker and cheaper, they replaced other raw materials like stone or rock. 

During the building boom of the 19th century, when more than 10 billion bricks were produced annually, many American cities like Boston and New York favoured locally made bricks. 

 

In Victorian London, due to the heavy fog, bright red bricks were chosen which made buildings much more visible. Although the amount of red pigment was reduced in bricks production, red remained the most desired colour for the brick and still does to this day. 

It was used by some of the 20th century’s most famous architects like Le Corbusier, F. L. Wright and Louis Khan. 
Nowadays, apart from wood, bricks seem to be commonly used building material. Consequently,  brick and terracotta architecture is dominant in its field with a great development in brick industry.

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Just now, mitsubishi said:

THE HISTORY OF BRICK WALLs

I will see if I can find something about bangng your head on one..hang on😀😝😀😩😦😚🤣😄🤯🤑😝😄😂😁

Man has used brick for building purpose for thousands of years. Bricks date back to 7000 BC, which makes them one of the oldest known building materials. They were discovered in southern Turkey at the site of an ancient settlement around the city of Jericho. 

The first bricks, made in areas with warm climates, were mud bricks dried in the sun for hardening. 
Ancient Egyptian bricks were made of clay mixed with straw. The evidence of this can be seen today at ruins of Harappa Buhen and Mohenjo-daro. Paintings on the tomb walls of Thebes portray Egyptian slaves mixing, tempering and carrying clay for the sun dried bricks. 

The greatest breakthrough came with the invention of fired brick in about 3,500 Bc. From this moment on, bricks could be made without the heat of sun and soon became popular in cooler climates. 

The Romans prefered to make their bricks in spring, then they stored them for two years before selling or using them. They only used white or red clay to manufacture bricks. 
The Romans succeeded in introducing fired bricks to the entire country thanks to mobile kilns. These were bricks stamped with the mark of the legion who supervised the brick production. Roman bricks differed in size and shape from other ancient bricks as they were more commonly round, square, oblong, triangular and rectangular. The kiln fired bricks measured 1 or 2 Roman feet by 1 Roman foot, and sometimes up to 3 Roman feet with larger ones. The Romans used brick for public and private buildings over the entire Roman empire. They built walls, forts, cultural centre, vaults, arches and faces of their aqueducts. The Herculaneum gate of Pompeii  and the baths of Caracalla in Rome  are examples of Roman brick structures.

 

 

During the period of the Roman Empire, the Romans spread the art of brickmaking throughout Europe and it continued to dominate during the medieval and Renaissance period.

When the Roman Empire fell, the art of brickmaking nearly vanished and it continued only in Italy and the Bizantine Empire. In the 11th century, brickmaking spread from these regions to France. 

 

During the 12th century bricks were reintroduced to northern Germany from northern Italy. This created the brick gothic period with buildings mainly built from fired red clay bricks. The examples of the Brick Gothic style buildings can be found in the Baltic countries such as Sweden, Denmark, Poland, Germany, Finland, Lithuania, Latvia, Estonia, Belarus and Russia. This period lacks in figural architectural sculptures which had previously been carved from stone. The Gothic figures were virtually impossible to create out of bricks at that time, but could be identified by the use of split courses of bricks in varying colours, red bricks, glazed bricks and white lime plaster. Eventually custom built and shaped bricks were introduced which could imitate the architectural sculptures. In the 16th century, Brick Gothic was replaced by Brick Renaissance architecture.    

In medieval times, the clay for making bricks often was kneaded by workers with their bare feet. They clay was shaped into brick by pushing it into a wooden frame placed on a table, which was covered with sand or straw to prevent the clay from sticking. After excess clay was wiped off with a stick, the brick was removed from the frame. 

In England the remains of buildings prove that the art of brickmaking was highly advanced by the time of Henry VIII. After the great fire of London in 1666, the city was rebuilt with mainly bricks. 

 

Adobe brick, which is sundried brick made of clay and straw, has been made for centuries in Central America, particularly in Mexico. Some Aztec adobe structures still exist, one example is the Pyramid of the Sun, built in the 15th century.

 

 

Bricks crossed the Atlantic with Dutch and British immigrants with some brickmasons among them. In Virginia brick structures were built as early as 1611. At that time it was common for brickmasons to make the bricks on the jobsite. It is known that bricks were transported from Virginia to Bermuda in 1621 in exchange for food and oil. 

Many early American skyscrapers are clad in brick or terracotta. It took 10 million bricks to build the Empire State Building. 

During the Renaissance and Baroque periods, exposed brick walls became less and less popular, consequently brickwork was covered in plaster. Only during the mid 18th century brick walls started to regain their popularity. 

 

Bricks were made by hand until about 1885. Once the Industrial Revolution broke out, the brickmaking machinery was introduced. Consequently, the number of clays that could be made into brick was greatly increased which influenced the production capacity. Handmade brick production ranged up to 36,000 bricks per week but by 1925 a brickmaking machine made 12,000 bricks a day. 

As brick structures could be built much quicker and cheaper, they replaced other raw materials like stone or rock. 

During the building boom of the 19th century, when more than 10 billion bricks were produced annually, many American cities like Boston and New York favoured locally made bricks. 

 

In Victorian London, due to the heavy fog, bright red bricks were chosen which made buildings much more visible. Although the amount of red pigment was reduced in bricks production, red remained the most desired colour for the brick and still does to this day. 

It was used by some of the 20th century’s most famous architects like Le Corbusier, F. L. Wright and Louis Khan. 
Nowadays, apart from wood, bricks seem to be commonly used building material. Consequently,  brick and terracotta architecture is dominant in its field with a great development in brick industry.

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Brick History

 
26-33 minutes

The History of Bricks and Brickmaking.

Bricks are one of the oldest known building materials dating back to 7000BC where they were first found in southern Turkey and around Jericho. The first bricks were sun dried mud bricks. Fired bricks were found to be more resistant to harsher weather conditions, which made them a much more reliable brick for use in permanent buildings, where mud bricks would not have been sufficient. Fired brick were also useful for absorbing any heat generated throughout the day, then releasing it at night

The Ancient Egyptians also used sun dried mud bricks as building materials, evidence of which can still be seen today at ruins such as Harappa Buhen and Mohenjo-daro. Paintings on the tomb walls of Thebes portray slaves mixing, tempering and carrying clay for the sun dried bricks. These bricks also consisted of a 4:2:1 ratio which enabled them to be laid more easily.

The Romans further distinguished those which had been dried by the sun and air and those bricks which were burnt in a kiln. Preferring to make their bricks in the spring, the Romans held on to their bricks for 2 years before they were used or sold. They only used clay which was whitish or red for their bricks.
Using mobile kilns, the Romans were successful in introducing kiln fired bricks to the whole of the Roman Empire. The bricks were then stamped with the mark of the legion who supervised the brick production. These bricks differed from other ancient bricks in size and shape. Roman bricks were more commonly round, square, oblong, triangular or rectangular. The kiln fired bricks were generally 1 or 2 Roman foot by 1 Roman foot, but with some larger bricks at up to 3 Roman feet. The Romans preferred this type of brick making during the first century of their civilisation and used the bricks for public and private buildings all over the empire.

The Greeks also considered perpendicular brick walls more durable than stone walls and used them for public edifices. They also realised how the modern brick was less susceptible to erosion than the old marble walls.

During the 12th century bricks were reintroduced to northern Germany from northern Italy. This created the brick gothic period which was a reduced style of Gothic architecture previously very common in northern Europe. The buildings around this time were mainly built from fired red clay bricks. Brick Gothic style buildings can be found in the Baltic countries Sweden, Denmark, Poland, Germany, Finland, Lithuania, Latvia, Estonia, Belarus and Russia. The brick gothic period can be categorized by the lack of figural architectural sculptures which had previously been carved in stone. The Gothic figures were impossible to create out of bulky bricks at that time, but could be identified by the use of split courses of bricks in varying colours, red bricks, glazed bricks and white lime plaster. Eventually special shaped bricks were introduced which would imitate the architectural sculptures.
During the renaissance and Baroque periods, exposed brick walls became unpopular and brickwork was generally covered by plaster. Only during the mid 18th century did visible brick walls again regain some popularity.

Bricks now

Bricks are more commonly used in the construction of buildings than any other material except wood. Brick and terracotta architecture is dominant within its field and a great industry has developed and invested in the manufacture of many different types of bricks of all shapes and colours. With modern machinery, earth moving equipment, powerful electric motors and modern tunnel kilns, making bricks has become much more productive and efficient. Bricks can be made from variety of materials the most common being clay but also calcium silicate and concrete. With clay bricks being the more popular, they are now manufactured using three processes soft mud, dry press and extruded. Also during 2007 the new ‘fly ash’ brick was created using the by-products from coal power plants.

Good quality bricks have a major advantage over stone as they are reliable, weather resistant and can tolerate acids, pollution and fire. Bricks can be made to any specification in colour, size and shape which makes bricks easier to build with than stone. Brickwork is also much cheaper than cut stone work. However there are some bricks which are more porous and therefore more susceptible to dampness when exposed to water. For best results in any construction work, the correct brick must be chosen in accordance with the job specifications.

Brick Composition

Building bricks are a mixture of clay and sand which is mixed with water to create the correct consistency. Sometimes the bricks also have added lime, ash or organic matter which speeds up the burning of the brick. The clay mixture is then formed in moulds to the desired specification ready to be dried then burnt in the kiln. Clay: The properties and quality of bricks depend on the type of clay used. The most common form of clay used for everyday bricks, is that with a sandy consistency, silicate or alumina, which usually contains small quantities of lime or iron oxide. Silica, when added to pure clay in the form of sand, prevents cracking, shrinking and warping. If there is a large proportion of sand used in the mixture the brick will be more textured and shapely. An excess of sand, however, renders the bricks too brittle and destroys cohesion. 25% of silica is said to be advantageous. Iron oxide in the clay enables the silica and alumina to fuse and adds considerably to the hardness and strength of the bricks. The iron content of the brick is evident in the colour of the brick and can be used to add the colour red into the bricks. However a clay which burns to a red colour will provide a stronger brick than clay which burns to a white or yellow brick. The lime content in a brick has two different effects. It stops the raw brick from shrinking and drying out, and it also acts as a flux during burning which causes the silica to melt and creates the bond which binds all the components of the brick together. However, too much lime can cause the brick to melt and loose shape. Any amount of quicklime within a brick is detrimental to its quality and can cause the brick to split into pieces. For the best qualities of pressed brick the clay is carefully selected both colour and composition. Clay from different sources is also often mixed together to create the desired mixture.

Manufacturing Processes

Handmade bricks used to be very commonly used throughout the UK. The process involves putting the clay, water and additives into a large pit where it is all mixed together by a tempering wheel generally still powered by horse power. Once the mixture is of the correct consistency, the clay is removed and pressed into moulds by hand. To prevent the brick from sticking to the mould, the brick is coated in either sand or water. Named ‘slop moulding’ when dipped in water and ‘sand struck’ when coated in sand. Coating the brick with sand however gives an overall better finish to the brick. Once shaped, the bricks are laid outside to dry by air and sun where they will be drying for three to four days. After this process the bricks are then transferred to the kiln for burning. If green bricks are left outside for the drying process and are left out during a shower; the water leaves an indentation of the brick is considered very undesirable. However this does not affect the strength properties of the bricks. Bricks are now more generally made by large scale manufacturing processes using machinery. This is a large scale effort and produces bricks which have been burned in patent kilns. There are three different types of manufacturing process for machine made bricks - the soft mud process, the stiff mud process and the dry clay process for which machines are specifically designed.

The ‘Soft mud ‘process is similar to that of handmade bricks. In the Soft Mud process that clay contains too much water to be extruded as the clay is left to soak in water for 24 hours. For this process three pits are usually in operation at any one time to keep the production flowing. Occasionally the clay is worked in a pug mill before being thrown into the machine. Due to the 20% water content of the clay, wooden moulds are generally used and are lined with either oil or sand to stop the clay sticking. After being drawn from the machine the filled moulds are emptied by hand and the bricks taken to the dry shed. So the soft mud bricks can be dried properly, both handmade soft mud bricks and machine made (more mass produced) bricks will both be placed in a large dryer which is separate from the extrusion dryer.

The ‘Stiff mud’ process differs because only enough water to create plasticity is added to the clay, approximately 12% water. Clay is then extruded through a ‘die’ to produce a long stream of pressed clay which is then cut to size by the machine. The die sizes and cutter wire are calculated to compensate for the shrinkage of the brick during drying and firing. Attachments can also be added to the die which gives the brick its texture from brush, roll, and scratch to roughen. Green bricks are then dried out carefully to ensure a consistent colour and strength. Because Soft Mud bricks have been created under little or no pressure, their density is not as great as that of Stiff Mud bricks. It has been argued that when Soft Mud bricks have been made and burned properly they are possibly the most durable brick. However Stiff mud bricks can have defects or planes of separation which can affect the bricks durability. However as Stiff Mud bricks are becoming increasingly cheaper to produce these are becoming the more popular.

The ‘Repressing’ of a brick is to re-shape the brick or round of any corners dependent on specification. Both types of soft mud and stiff mud bricks can be repressed when they are only partially dried. This is done by placing the bricks in metal moulds and putting them under great pressure before burning. Pressed bricks however are machine moulded bricks where the clay being used is already nearly dry. This process can make a significant difference on the appearance of the bricks. Bricks made using this process generally are more difficult to compress. Dry pressed bricks however are now commonly used for face bricks. Pressed bricks generally mean dry pressed bricks, but many face bricks are made by repressing soft mud bricks.

Cement’ bricks made from Portland cement, these bricks are machine moulded into size and shape to match the size of clay bricks. These are extensively used in some regions.

Hollow, Terracotta or Tile’. This type of product can made into practically and size or shape for any kind of use. Blocks made of terra-cotta are light and durable. For use in partitions the terra-cotta is mixed with sawdust which burns off in the kiln, but creates a more porous brick. Terra-cotta can be glazed or unglazed.

Facing Bricks Types of:-

Facing bricks are uniform in colour and shape and can now be made to any almost any specification, texture, colour and size.

Wirecut extruded bricks. For this type of brick the clay is extruded and cut by wore into individual bricks. This is a very cost effective way of producing bricks and is done by an automated production process. These bricks are readily available in a variety of styles and colours.

Stock bricks; are usually slightly more expensive than wirecut Bricks. These are a soft mud brick which are sometimes irregular in shape.

Handmade bricks; as previously discussed above, handmade bricks are very desirable and individual in shape and colour. This brick is one of the most expensive sorts of brick.

Fletton or London Brick; is a brick made from clay extracted from the south east of England which contains traces of oil which is burnt off during the burning process in the kiln.

Arch and Clinker bricks This term is used for bricks which are burned immediately. They are over burnt and sometimes distorted in shape. Body, Cherry and/or hard bricks. These bricks are of a higher quality and are generally the bricks that were in the centre of the pile of bricks which have been burned. These bricks are top bricks as they have a higher overall quality and finish. Cherry is used as a term when the clay which has been used burns red.

Salmon, Pale or Soft bricks. These are the bricks which were nearer to the outside of the kiln during burning which means they are slightly under burnt. These bricks are generally softer than the bricks taken from the centre of the kiln are therefore are of a lesser quality, although this does not affect the overall shape of the brick. These bricks are generally used for the interior of walls.

Waterstruck Brick This type of brick is a soft mud moulded brick. It uses alluvial clay which deposited at the end of the last ice age. The clay is pressed into mould lined with silicate. When the bricks are removed from their mould, they are left with a textured effect which can only be achieved using this method. This type of brick looks old and handmade even when new.

Engineering Bricks Engineering bricks are called so due to their overall strength and water absorption. The Class A brick has strength of 125N/mm² and water absorption of less than 4.5%. Class B engineering bricks have a strength greater than 75N/mm² and water absorption of less than 7%. Traditionally used in civil engineering, these bricks are also useful for damp courses and structural design.

Bullnose Bricks These special bricks are used when round edges are needed, for gate recesses, quadrants or arches.

Off Shades or Seconds or ATR or Random Quality. These are batches of bricks which are generally consistent in colour but do not match the product which is marketed.

Different uses for bricks

Dependant on their final use, the bricks are named accordingly.
Radial Bricks either have one edge shorter than the other or vary in thickness. This type of brick is used for walls with curved edges. Arch bricks are used for arches as they have one end thicker than the other.
Ordinary bricks or facebricks and have regular shape and colour used for the outside of building etc.
Fire bricks are generally yellow in colour and used in places where they would be subject to high temperatures. Paving bricks are of uniform size and colour and have been made by burning hard clay or shale. Good brick to be used where toughness and water tightness is essential. Aesthetic appearance
Bricks can be made to virtually any specification,Overall strength and water absorption of clay bricks Compressive strengths vary from 5 N/mm2 to 125N/mm2
Water absorption varies from 6-26% dependant on brick type
Brick Dimensions Metric and imperial

Brick Sizes
Metric bricks are a little smaller than the old imperial one. New bricks can be bonded into old brickwork by slightly increasing the mortar bed joint. Brick sizes have remained fairly constant over the years :-

Metric and Imperial 215 × 102.5 × 50

Standard Metric215 × 102.5 × 65

Metric 225 × 107.5 × 67

Imperial 230 × 110 × 70

Imperial 230 × 110 × 73

Imperial 230 × 110 × 76

Imperial 230 × 110 × 80

Although in the UK, the depth used to be less (about 2 ins/51mm) whereas modern bricks are about 2.5 ins/64mm.


Brick Cutting

Brick cuttingis the process of cutting bricks into the desired size or in most cases to cut and bond them together using an epoxy mortar to form angle bricks these are mainly used on bay windows and conservatories etc.

Thermal Efficiency and Compliance with Building Regulations http://www.bbacerts.co.uk/

Kiln Brick Burning
After all bricks have been allowed time to dry they are placed in a kiln for burning which finishes off the brick to achieve the optimum strength and colour.
There a few different types of kilns which are currently used to burn bricks.


The Scotch Kiln is the most commonly used in the UK. This is a rectangular building which is open at the top and has side doors with fireholes built from fire bricks. The kilns will contain approximately 80, 000 bricks at full capacity. Raw bricks are arranged in the kiln leaving gaps in between each brick to ensure an even burn. It takes approximately three days to burn off the moisture from the bricks, at which point the firing is increased for the final burn. It takes between 48 and 60 hours to completely burn a brick to achieve its maximum strength. As mentioned before the bricks from the centre of kiln will be of the highest quality whilst the ones from the edges are sometimes clinkered and unsuitable for exterior work.
Up Draft Kiln. Used more frequently for handmade bricks and in small brick yards, this old fashioned kiln is only up to 15 feet high.
Down Draft Kilns are generally of a beehive type shape with fire produced outside of the kiln and carried in through flues. It is believed that all types of clay whether it be pottery or brick work, burn more evenly in a down draft kiln. For Terra-cotta brickwork this type of kiln is usually used.
Continuous kilns are the most expensive type of kiln to construct. This type of kiln is a continuously fired tunnel in which the bricks pass through very slowly on a rail to achieve a consistently durable brick. This is continuous conveyor belt with bricks being dried and added at one end while at the other end they are being burnt. This is a very efficient way of burning bricks. They also achieve a greater number of grade 1 bricks using this method.


The colour of brick is influenced by the chemical and mineral content of the mixture but also how high the temperature was during burning. Bricks are generally red, but an increase in temperature can change them to dark red, purple, brown or grey. Bricks containing silicate depend on the colourant used. The colour and place of manufacture is reflected in the brick names.


Mortars
To make any kind of brick work complete it must be plied together with mortar. The way in which the bricks are bonded together is vital to the strength of the overall structure. Concrete mortars contain aggregates of more than 5mm where as mortar contains aggregates less than 5mm.
General purpose mortar contains either
Sand, lime and cement
Sand and masonry cement
Sand, cement and plasticiser
Mortar is then graded between 1 and 5 depending on strength. 5 being the weakest.
Mortar Cement-Lime-Sand Cement- Sand Cement – Sand-plasticiser
The mixture has to be mixed together with clean water before it is ready to use
Normal bricks should be laid on a bed of mortar at least 3/16" and no more than 3/8" thick. For a course of bricks 8 courses high, your mortar should not exceed 2" in total. With pressed bricks being smoother a mortar joint of 1/8" can be used. For rough stone work a mortar with rough sand can be used, but for pressed brickwork it must be very fine sand.

Lime Mortar

Slaked lime is used to make lime mortar. The mortar is made by mixing sand with slaked lime at the proportion of 1 part lime to 5 parts sand. There are two types of lime used in lime mortars, one that sets and hardens by the reaction with the air (non-hydraulic) and one which sets by reaction to the water (hydraulic).
Non-hydraulic lime is made from pure calcium carbonate, or chalk or limestone. This is burned in a kiln to create calcium oxide or quicklime. When this is slaked with water it takes on another form as calcium hydroxide. Calcium hydroxide reacts with the air to set. This is what sets the brickwork together and creates the strength.

Hydraulic Limes. Calcium carbonates naturally occur but can include some impurities. It is these impurities which when burned in a kiln create the calcium silicates or aluminates that react with water to set. Enough water is added to the mixture to create calcium hydroxide powder form. The hydraulic lime is then graded depending on their overall set strength.

White and Coloured Mortar

White and coloured mortars should be made using lime putty and screened sand. Colour is created by adding additional minerals to the white mortar. Coloured mortars are not as strong as white mortars. However the more popular mortar colours are red, brown, buff and black, green, purple and grey.
Cement Mortars
Cement mortars should be used in areas of damp or below grade work, also in places which will have heavy loads such as arches. Cement mortars should also be used for setting coping stones or where the brick work will be exposed to the elements. For under water construction Portland cement mortars should be used.
Mortar Tinting from Bricks UK available at http://www.extensionmatch.co.uk/motartinting.html
When new extensions or refurbished brick and stonework are being carried out, matching the mortar joint with the original brick work can be a problem. Extension Match colour tinting extends to mortar tinting. We can match mortar colours perfectly and permanently and all work is guaranteed for the life of the brickwork.
Grout can also be tinted. Shown below is a tiled bathroom floor - the customer was not happy with the original grout finish so we tinted the grout joint which transformed the overall appearance of the tiled floor.
For example

Brick Tinting from Bricks UK available at http://www.extensionmatch.co.uk/motartinting.html Brick tinting has been used for decades by brick and masonry manufacturers and also by many developers on new house sites when there are problems between different batches of manufactured bricks, delivered on site which causes slight shade and colour differences between one lorry load of bricks and another. Tinting is then used to match the affected bricks to the colour of the original bricks, seamlessly blending the different batches together. Brick tinters do not "paint" the brick with pre-set coloured paints, the process is a chemical and oxide solution involving various colour dyes. Each match is unique and the dye is mixed on site by our specialists once they have assessed the required colours to match, including and varying blends.Matching and creating the colour on site ensures that we get the exact colour dye solution to match your individual brick in your individual situation.
The solutions change the produced colour of the brick, it is not a paint simply applied to the face of the brick, it will naturally whether just as the normal brick would, mature over the years. All work is fully guaranteed for the life of the brick.

Brickwork Bonds
Brickwork bonding is how the bricks are arranged. They usually overlap in between courses which helps distribute the load and provide a more stable structure. General brickwork should not be less than ¼ bonded with mortar.

Stretcher bond

This bond is the most commonly used today. Bricks used to make this bond are just half a
brick wide. As with any brickwork, no two adjacent vertical joints should be in line. When
turning a corner at the end of straight run, the two runs should be interlocked on every other
course.

English Bond

An English bond has alternating courses of headers and stretchers. The alternative headers
should be centred over and under the vertical joints.

Flemish Bond

This bond has alternating headers and stretchers along each course. The headers should be
centred above the stretchers above and below.


American Common Bond

This bond is very similar to the English Bond but its headers run one in every six courses of
stretchers.


Header Bond

This type of bond is used for walls which need to be curved. It is made by full bricks laid
header wise with a ¾ bat on alternate courses.

Pointing
Pointing is effectively the application and maintenance of the mortar which bonds the brickwork. After the masonry has been laid, the gaps are in filled with mortar, this is known as pointing. Pointing should not be done during any extreme hot or cold weather.
If re-pointing, any vegetation growing on the mortar should be removed and the existing mortar should be chiselled back. This should be done using either s plugging chisel, club hammer or mini angle grinder to a depth of 13mm.
All the debris should then be washed off and the walls should be left to dry before the re-pointing begins. The mortar used for the pointing should be 1 : 3 parts and be quite stiff so the mixture does not fall of the trowel.

Different types of Pointing

Weather Struck Joint

Weather Struck and Cut Pointing

Similar to the previous weather struck joint, except the bed joints are neatly trimmed using a Frenchman or pointing trowel.

Tooled, Bucket Handel Joint

The most popular joint used today, where the joint bed is slightly rounded inwards. The mortar should not be pressed in too hard. The tool needed for this job is a rubber hose, an old type bucket handle.

Flush or Rag Joint

This finish of this joint is flush with the brick work, smoothed off with a rag. This finish should only be used for brickwork above water level.

Recessed Joints

This Finish of this joint is recessed. The mortar is formed to a consistence depth of approximately 5 mm. This joint should only be used with a frost resistant brick and is not recommended where the brickwork could be exposed to severe wind driven rain.


This type of joint should be used when the bricks have become uneven over time due to weathering. The joint is pointed by filling the perp joint first and then the bed joint which would be shaped by placing the trowel on the perp joint and angling it downwards to create a smooth finish.

With thanks to www.expressbrick.com

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BRICS information portal

 
9-11 minutes

BRICS is an informal group of states comprising the Federative Republic of Brazil, the Russian Federation, the Republic of India, the People’s Republic of China and the Republic of South Africa.

It was the Russian side that initiated the creation of BRICS.

On 20 September 2006, the first BRICS Ministerial Meeting was held at the proposal of Russian President Vladimir Putin on the margins of a UN General Assembly Session in New York. Foreign ministers of Russia, Brazil and China and the Indian Defence Minister took part in the meeting. They expressed their interest in expanding multilateral cooperation.

On 16 May 2008, Yekaterinburg hosted Meeting of BRICS Foreign Ministers on the initiative of Russia. After the meeting, a Joint Communique was issued, reflecting common stances on topical global development issues.

Another important step was taken on 9 July 2008, when Russian President Dmitry Medvedev met with Brazilian President Luiz Inacio Lula da Silva, Indian Prime Minister Manmohan Singh and Chinese President Hu Jintao on the margins of the G8 Summit in Toyako, Japan, on the Russian initiative.

On the Russian initiative on 16 June 2009, Yekaterinburg hosted the first BRIC Summit. BRIC Leaders issued a joint statement after the Summit. The document set forth the goals of BRIC “to promote dialogue and cooperation among our countries in an incremental, proactive, pragmatic, open and transparent way. The dialogue and cooperation of the BRIC countries is conducive not only to serving common interests of emerging market economies and developing countries, but also to building a harmonious world of lasting peace and common prosperity.” The document outlined a common perception of ways to cope with the global financial and economic crisis.

The growing economic might of BRICS countries, their significance as one of the main driving forces of global economic development, their substantial population and abundant natural resources form the foundation of their influence on the international scene.

In 2013, BRICS accounted for about 27 percent of the global GDP (in terms of the purchasing power parity of their national currencies). The total BRICS population is 2.88 billion (42 percent of the entire global population), and the five countries cover 26 percent of the planet’s land.

BRICS countries are influential members of leading international organisations and agencies, including the UN, the G20, the Non-Aligned Movement and the Group of 77. They are also members of various regional associations. The Russian Federation is a member of the Commonwealth of Independent States, the Collective Security Treaty Organisation and the Eurasian Economic Union. Russia and China are members of the Shanghai Cooperation Organisation and the Asia Pacific Economic Cooperation. Brazil is a member of the Union of South American Nations, MERCOSUR and the Community of Latin American and Caribbean States. The Republic of South Africa is a member of the African Union and the Southern African Development Community. India is a member of the South Asian Association for Regional Cooperation.

Relations between BRICS partners are built on the UN Charter, generally recognised principles and norms of international law and the following principles, which were agreed by member countries at their 2011 Summit: openness, pragmatism, solidarity, non-bloc nature and neutrality with regard to third parties.

BRICS work is based on action plans approved during annual summits since 2010.

The system of cooperation formats between BRICS countries includes annual scheduled summits (2010 – Brazil; 2011 – China; 2012 – India; 2013 – South Africa; 2014 – Brazil; 2015 - Russia; 2016 - India), leaders’ meetings on the sidelines of G20 summits, meetings between high representatives responsible for national security, foreign ministers (on the sidelines of the UN General Assembly), ministers of finance and governors of central banks (on the sidelines of autumn and spring meetings of the International Monetary Fund and World Bank boards of governors and also on the sidelines of meetings of G20 ministers of finance), ministers of agriculture and agrarian development, BRICS sherpas and sous-sherpas, heads of statistical and anti-monopoly departments, senior officials for science and technological and innovation cooperation, meetings of working cooperation groups for agriculture and agrarian development, healthcare, information security, science and innovation, meetings of chairpersons of supreme (high) courts, heads of central election commissions, and representatives of municipal administrations and partner regions.

Cooperation between national BRICS permanent missions at the UN Headquarters in New York, at international organisations in Geneva and Vienna and at UNESCO in Paris plays an important role in the mechanism of multilateral cooperation.

Apart from joint events involving executive agencies and the judiciary branch, business organisations and research centres cooperate within the BRICS format.

In 2009-2016 BRICS countries focused on the following joint priorities. They worked out a common stance on certain regional problems, including the Libyan, Syrian and Afghan problems and the Iranian nuclear programme. They also reached common agreement on financial and economic issues, including World Bank and IMF reforms, measures to ensure that sufficient resources can be mobilized to the IMF to strengthen its anti-crisis potential, the creation of BRICS Interbank Cooperation Mechanism which provides for Extending Credit Facility in Local Currency and the establishment of the BRICS Exchanges Alliance.

BRICS is successfully expanding its external relations that were established at the Durban meeting between the five BRICS leaders, the leaders of the African Union and the leaders of eight leading African integration associations. On 16 July 2014, Brasilia hosted the second meeting in this format involving South American heads of state and government. This practice makes it possible to find important points of contact between BRICS and new leading centres of power that are emerging worldwide.

The 6th BRICS Summit (Fortaleza and Brasilia, 15-16 July 2014) produced a highly important result. The sides signed the Agreement on the New Development Bank and the Treaty for the Establishment of a BRICS Contingent Reserve Arrangement. These institutions will possess a total of $200 billion.

The Leaders also adopted a key decision on launching comprehensive talks regarding the BRICS Strategy for Economic Partnership and a draft BRICS Roadmap for BRICS Trade, Economic and Investment Cooperation.

The sides also coordinated subsequent joint steps in topical areas of cooperation such as the resolution of conflicts, IMF reform, the fight against illicit drug trafficking, the use and development of information and communications technologies on the basis of international cooperation and generally recognised principles and norms of international law and the creation of favourable conditions for barrier-free trade.

During the VII Summit (Ufa, 8-9 July 2015) BRICS leaders signed Ufa Declaration, Ufa Plan of Actions and Strategy for BRICS Economic Partnership that confirmed the strategic character of BRICS countries partnership and determined the directions of five countries long-term cooperation. Within the framework of the summit a Memorandum of Understanding to establish BRICS joint website board and the Agreement between the BRICS Governments of cultural cooperation were signed.

BRICS leaders reached an agreement  to open a number of new spheres of cooperation, initiated by the Russian Presidency – in the field of youth, migration, industry, energy, peacekeeping, environment, fight against infectious diseases etc.

The Russian side also presentedfuck german cunts and jew cunt task force shite idea a Roadmap for trade-economic and investment cooperation between the BRICS countries up to 2020 year, which currently includes more than 60 proposals of cooperation from Russian companies.

In 2016, India became the head of the Association. The culmination of its presidency was the eighth summit of BRICS, which was held in the Indian state of Goa on 15-16 October. Its motto was "The Formation of popular, inclusive and collective decisions". The leaders of five countries signed the Declaration of Goa, which expressed a coherent position on issues related to the development of the Association and critical issues.

At the summit in Goa were discussed the issues of energy, trade, banking cooperation, agriculture, space utilization and other common spaces, health, education, development of humanitarian contacts and tourism, the fight against poverty and social inequality. In addition to the Declaration was signed a number of sectoral agreements.

The BRICS presidency in 2017 were transferred to China, in 2018 - to South Africa, in 2019 - to Brazil and in 2020 - to Russia.

Summit of the BRICS will be held in St. Peterburg in July.

Dont forget to like and subscribe

 

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1 minute ago, mitsubishi said:

You see what I did here?

BRICS information portal

 
9-11 minutes

BRICS is an informal group of states comprising the Federative Republic of Brazil, the Russian Federation, the Republic of India, the People’s Republic of China and the Republic of South Africa.

It was the Russian side that initiated the creation of BRICS.

On 20 September 2006, the first BRICS Ministerial Meeting was held at the proposal of Russian President Vladimir Putin on the margins of a UN General Assembly Session in New York. Foreign ministers of Russia, Brazil and China and the Indian Defence Minister took part in the meeting. They expressed their interest in expanding multilateral cooperation.

On 16 May 2008, Yekaterinburg hosted Meeting of BRICS Foreign Ministers on the initiative of Russia. After the meeting, a Joint Communique was issued, reflecting common stances on topical global development issues.

Another important step was taken on 9 July 2008, when Russian President Dmitry Medvedev met with Brazilian President Luiz Inacio Lula da Silva, Indian Prime Minister Manmohan Singh and Chinese President Hu Jintao on the margins of the G8 Summit in Toyako, Japan, on the Russian initiative.

On the Russian initiative on 16 June 2009, Yekaterinburg hosted the first BRIC Summit. BRIC Leaders issued a joint statement after the Summit. The document set forth the goals of BRIC “to promote dialogue and cooperation among our countries in an incremental, proactive, pragmatic, open and transparent way. The dialogue and cooperation of the BRIC countries is conducive not only to serving common interests of emerging market economies and developing countries, but also to building a harmonious world of lasting peace and common prosperity.” The document outlined a common perception of ways to cope with the global financial and economic crisis.

The growing economic might of BRICS countries, their significance as one of the main driving forces of global economic development, their substantial population and abundant natural resources form the foundation of their influence on the international scene.

In 2013, BRICS accounted for about 27 percent of the global GDP (in terms of the purchasing power parity of their national currencies). The total BRICS population is 2.88 billion (42 percent of the entire global population), and the five countries cover 26 percent of the planet’s land.

BRICS countries are influential members of leading international organisations and agencies, including the UN, the G20, the Non-Aligned Movement and the Group of 77. They are also members of various regional associations. The Russian Federation is a member of the Commonwealth of Independent States, the Collective Security Treaty Organisation and the Eurasian Economic Union. Russia and China are members of the Shanghai Cooperation Organisation and the Asia Pacific Economic Cooperation. Brazil is a member of the Union of South American Nations, MERCOSUR and the Community of Latin American and Caribbean States. The Republic of South Africa is a member of the African Union and the Southern African Development Community. India is a member of the South Asian Association for Regional Cooperation.

Relations between BRICS partners are built on the UN Charter, generally recognised principles and norms of international law and the following principles, which were agreed by member countries at their 2011 Summit: openness, pragmatism, solidarity, non-bloc nature and neutrality with regard to third parties.

BRICS work is based on action plans approved during annual summits since 2010.

The system of cooperation formats between BRICS countries includes annual scheduled summits (2010 – Brazil; 2011 – China; 2012 – India; 2013 – South Africa; 2014 – Brazil; 2015 - Russia; 2016 - India), leaders’ meetings on the sidelines of G20 summits, meetings between high representatives responsible for national security, foreign ministers (on the sidelines of the UN General Assembly), ministers of finance and governors of central banks (on the sidelines of autumn and spring meetings of the International Monetary Fund and World Bank boards of governors and also on the sidelines of meetings of G20 ministers of finance), ministers of agriculture and agrarian development, BRICS sherpas and sous-sherpas, heads of statistical and anti-monopoly departments, senior officials for science and technological and innovation cooperation, meetings of working cooperation groups for agriculture and agrarian development, healthcare, information security, science and innovation, meetings of chairpersons of supreme (high) courts, heads of central election commissions, and representatives of municipal administrations and partner regions.

Cooperation between national BRICS permanent missions at the UN Headquarters in New York, at international organisations in Geneva and Vienna and at UNESCO in Paris plays an important role in the mechanism of multilateral cooperation.

Apart from joint events involving executive agencies and the judiciary branch, business organisations and research centres cooperate within the BRICS format.

In 2009-2016 BRICS countries focused on the following joint priorities. They worked out a common stance on certain regional problems, including the Libyan, Syrian and Afghan problems and the Iranian nuclear programme. They also reached common agreement on financial and economic issues, including World Bank and IMF reforms, measures to ensure that sufficient resources can be mobilized to the IMF to strengthen its anti-crisis potential, the creation of BRICS Interbank Cooperation Mechanism which provides for Extending Credit Facility in Local Currency and the establishment of the BRICS Exchanges Alliance.

BRICS is successfully expanding its external relations that were established at the Durban meeting between the five BRICS leaders, the leaders of the African Union and the leaders of eight leading African integration associations. On 16 July 2014, Brasilia hosted the second meeting in this format involving South American heads of state and government. This practice makes it possible to find important points of contact between BRICS and new leading centres of power that are emerging worldwide.

The 6th BRICS Summit (Fortaleza and Brasilia, 15-16 July 2014) produced a highly important result. The sides signed the Agreement on the New Development Bank and the Treaty for the Establishment of a BRICS Contingent Reserve Arrangement. These institutions will possess a total of $200 billion.

The Leaders also adopted a key decision on launching comprehensive talks regarding the BRICS Strategy for Economic Partnership and a draft BRICS Roadmap for BRICS Trade, Economic and Investment Cooperation.

The sides also coordinated subsequent joint steps in topical areas of cooperation such as the resolution of conflicts, IMF reform, the fight against illicit drug trafficking, the use and development of information and communications technologies on the basis of international cooperation and generally recognised principles and norms of international law and the creation of favourable conditions for barrier-free trade.

During the VII Summit (Ufa, 8-9 July 2015) BRICS leaders signed Ufa Declaration, Ufa Plan of Actions and Strategy for BRICS Economic Partnership that confirmed the strategic character of BRICS countries partnership and determined the directions of five countries long-term cooperation. Within the framework of the summit a Memorandum of Understanding to establish BRICS joint website board and the Agreement between the BRICS Governments of cultural cooperation were signed.

BRICS leaders reached an agreement  to open a number of new spheres of cooperation, initiated by the Russian Presidency – in the field of youth, migration, industry, energy, peacekeeping, environment, fight against infectious diseases etc.

The Russian side also presentedfuck german cunts and jew cunt task force shite idea a Roadmap for trade-economic and investment cooperation between the BRICS countries up to 2020 year, which currently includes more than 60 proposals of cooperation from Russian companies.

In 2016, India became the head of the Association. The culmination of its presidency was the eighth summit of BRICS, which was held in the Indian state of Goa on 15-16 October. Its motto was "The Formation of popular, inclusive and collective decisions". The leaders of five countries signed the Declaration of Goa, which expressed a coherent position on issues related to the development of the Association and critical issues.

At the summit in Goa were discussed the issues of energy, trade, banking cooperation, agriculture, space utilization and other common spaces, health, education, development of humanitarian contacts and tourism, the fight against poverty and social inequality. In addition to the Declaration was signed a number of sectoral agreements.

The BRICS presidency in 2017 were transferred to China, in 2018 - to South Africa, in 2019 - to Brazil and in 2020 - to Russia.

Summit of the BRICS will be held in St. Peterburg in July.

Dont forget to like and subscribe

 

Brick - Wikipedia

Authority control GND: 4067726-6 LCCN: sh85016808 NDL: 00569393 NKC: ph119240
30-38 minutes

220px-Brick.jpg

220px-Brick_wall_close-up_view.jpg

A wall constructed in glazed-headed Flemish bond with bricks of various shades and lengths

220px-Concrete_wall.jpg

An old brick wall in English bond laid with alternating courses of headers and stretchers

A brick is building material used to make walls, pavements and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote rectangular units made of clay-bearing soil, sand, and lime, or concrete materials. Bricks can be joined together using mortar, adhesives or by interlocking them.[1][2] Bricks are produced in numerous classes, types, materials, and sizes which vary with region and time period, and are produced in bulk quantities. Two basic categories of bricks are fired and non-fired bricks.

Block is a similar term referring to a rectangular building unit composed of similar materials, but is usually larger than a brick. Lightweight bricks (also called lightweight blocks) are made from expanded clay aggregate.

Fired bricks are one of the longest-lasting and strongest building materials, sometimes referred to as artificial stone, and have been used since circa 4000 BC. Air-dried bricks, also known as mudbricks, have a history older than fired bricks, and have an additional ingredient of a mechanical binder such as straw.

Bricks are laid in courses and numerous patterns known as bonds, collectively known as brickwork, and may be laid in various kinds of mortar to hold the bricks together to make a durable structure.

History[edit]

220px-Historic_brick_street_in_Natchitoc

Middle East and South Asia[edit]

220px-Subrahmanya_Temple%2C_Saluvanakupp

170px-Shebli2.jpg

170px-JetawanaStupa1.JPG

The earliest bricks were dried brick, meaning that they were formed from clay-bearing earth or mud and dried (usually in the sun) until they were strong enough for use. The oldest discovered bricks, originally made from shaped mud and dating before 7500 BC, were found at Tell Aswad, in the upper Tigris region and in southeast Anatolia close to Diyarbakir.[3] The South Asian inhabitants of Mehrgarh also constructed, and lived in, air-dried mudbrick houses between 7000–3300 BC.[4] Other more recent findings, dated between 7,000 and 6,395 BC, come from Jericho, Catal Hüyük, the ancient Egyptian fortress of Buhen, and the ancient Indus Valley cities of Mohenjo-daro, Harappa,[5] and Mehrgarh.[6] Ceramic, or fired brick was used as early as 3000 BC in early Indus Valley cities like Kalibangan.[7]

China[edit]

The earliest fired bricks appeared in Neolithic China around 4400 BC at Chengtoushan, a walled settlement of the Daxi culture.[8] These bricks were made of red clay, fired on all sides to above 600 °C, and used as flooring for houses. By the Qujialing period (3300 BC), fired bricks were being used to pave roads and as building foundations at Chengtoushan.[9]

Bricks continued to be used during 2nd millennium BC at a site near Xi'an.[10] Fired bricks were found in Western Zhou (1046–771 BC) ruins, where they were produced on a large scale.[11][12][13] The carpenter's manual Yingzao Fashi, published in 1103 at the time of the Song dynasty described the brick making process and glazing techniques then in use. Using the 17th-century encyclopaedic text Tiangong Kaiwu, historian Timothy Brook outlined the brick production process of Ming Dynasty China:

...the kilnmaster had to make sure that the temperature inside the kiln stayed at a level that caused the clay to shimmer with the colour of molten gold or silver. He also had to know when to quench the kiln with water so as to produce the surface glaze. To anonymous labourers fell the less skilled stages of brick production: mixing clay and water, driving oxen over the mixture to trample it into a thick paste, scooping the paste into standardised wooden frames (to produce a brick roughly 42 cm long, 20 cm wide, and 10 cm thick), smoothing the surfaces with a wire-strung bow, removing them from the frames, printing the fronts and backs with stamps that indicated where the bricks came from and who made them, loading the kilns with fuel (likelier wood than coal), stacking the bricks in the kiln, removing them to cool while the kilns were still hot, and bundling them into pallets for transportation. It was hot, filthy work.

Europe[edit]

220px-Trier_Kurfuerstliches_Palais_BW_4.

170px-LandshutStMartin01.jpg

220px-Panorama_of_Malbork_Castle%2C_part

170px-Chilehaus.jpg

Early civilisations around the Mediterranean adopted the use of fired bricks, including the Ancient Greeks and Romans. The Roman legions operated mobile kilns,[14] and built large brick structures throughout the Roman Empire, stamping the bricks with the seal of the legion.

During the Early Middle Ages the use of bricks in construction became popular in Northern Europe, after being introduced there from Northern-Western Italy. An independent style of brick architecture, known as brick Gothic (similar to Gothic architecture) flourished in places that lacked indigenous sources of rocks. Examples of this architectural style can be found in modern-day Denmark, Germany, Poland, and Russia.

This style evolved into Brick Renaissance as the stylistic changes associated with the Italian Renaissance spread to northern Europe, leading to the adoption of Renaissance elements into brick building. A clear distinction between the two styles only developed at the transition to Baroque architecture. In Lübeck, for example, Brick Renaissance is clearly recognisable in buildings equipped with terracotta reliefs by the artist Statius von Düren, who was also active at Schwerin (Schwerin Castle) and Wismar (Fürstenhof).

Long-distance bulk transport of bricks and other construction equipment remained prohibitively expensive until the development of modern transportation infrastructure, with the construction of canal, roads, and railways.

Industrial era[edit]

Production of bricks increased massively with the onset of the Industrial Revolution and the rise in factory building in England. For reasons of speed and economy, bricks were increasingly preferred as building material to stone, even in areas where the stone was readily available. It was at this time in London that bright red brick was chosen for construction to make the buildings more visible in the heavy fog and to help prevent traffic accidents.[15]

The transition from the traditional method of production known as hand-moulding to a mechanised form of mass-production slowly took place during the first half of the nineteenth century. Possibly the first successful brick-making machine was patented by Henry Clayton, employed at the Atlas Works in Middlesex, England, in 1855, and was capable of producing up to 25,000 bricks daily with minimal supervision.[16] His mechanical apparatus soon achieved widespread attention after it was adopted for use by the South Eastern Railway Company for brick-making at their factory near Folkestone.[17] The Bradley & Craven Ltd 'Stiff-Plastic Brickmaking Machine' was patented in 1853, apparently predating Clayton. Bradley & Craven went on to be a dominant manufacturer of brickmaking machinery.[18] Predating both Clayton and Bradley & Craven Ltd. however was the brick making machine patented by Richard A. Ver Valen of Haverstraw, New York in 1852.[19]

The demand for high office building construction at the turn of the 20th century led to a much greater use of cast and wrought iron, and later, steel and concrete. The use of brick for skyscraper construction severely limited the size of the building – the Monadnock Building, built in 1896 in Chicago, required exceptionally thick walls to maintain the structural integrity of its 17 storeys.

Following pioneering work in the 1950s at the Swiss Federal Institute of Technology and the Building Research Establishment in Watford, UK, the use of improved masonry for the construction of tall structures up to 18 storeys high was made viable. However, the use of brick has largely remained restricted to small to medium-sized buildings, as steel and concrete remain superior materials for high-rise construction.[20]

Types[edit]

220px-2008_BeaconHill_Boston_2302897829.

There are thousands of types of bricks that are named for their use, size, forming method, origin, quality, texture, and/or materials.

Categorized by manufacture method:

  • Extruded – made by being forced through an opening in a steel die, with a very consistent size and shape.
    • Wire-cut – cut to size after extrusion with a tensioned wire which may leave drag marks
  • Moulded – shaped in moulds rather than being extruded
    • Machine-moulded – clay is forced into moulds using pressure
    • Handmade – clay is forced into moulds by a person
  • Dry-pressed – similar to soft mud method, but starts with a much thicker clay mix and is compressed with great force.

Categorized by use:

  • Common or building – A brick not intended to be visible, used for internal structure
  • Face – A brick used on exterior surfaces to present a clean appearance
  • Hollow – not solid, the holes are less than 25% of the brick volume
    • Perforated – holes greater than 25% of the brick volume
  • Keyed – indentations in at least one face and end to be used with rendering and plastering
  • Paving – brick intended to be in ground contact as a walkway or roadway
  • Thin – brick with normal height and length but thin width to be used as a veneer

Specialized use bricks:

  • Chemically resistant – bricks made with resistance to chemicals
  • Engineering – a type of hard, dense, brick used where strength, low water porosity or acid (flue gas) resistance are needed. Further classified as type A and type B based on their compressive strength
    • Accrington – a type of engineering brick from England
  • Fire or refractory – highly heat-resistant bricks
    • Clinker – a vitrified brick
    • Ceramic glazed – fire bricks with a decorative glazing

Bricks named for place of origin:

  • Cream City brick – a light yellow brick made in Milwaukee, Wisconsin
  • Dutch – a hard light coloured brick originally from the Netherlands
  • Fareham red brick – a type of construction brick
  • London stock – type of handmade brick which was used for the majority of building work in London and South East England until the growth in the use of machine-made bricks
  • Nanak Shahi bricks – a type of decorative brick in India
  • Roman – a long, flat brick typically used by the Romans
  • Staffordshire blue brick – a type of construction brick from England

Methods of manufacture[edit]

170px-BrickMakingTurnOfTheCentury.jpg

Brick making at the beginning of the 20th century

Three basic types of brick are un-fired, fired, and chemically set bricks. Each type is manufactured differently.

Mudbrick[edit]

Unfired bricks, also known as mudbricks, are made from a wet, clay-containing soil mixed with straw or similar binders. They are air-dried until ready for use.

Fired brick[edit]

170px-Brick_making_in_Java.jpg

Raw bricks sun-drying before being fired

Fired bricks are burned in a kiln which makes them durable. Modern, fired, clay bricks are formed in one of three processes – soft mud, dry press, or extruded. Depending on the country, either the extruded or soft mud method is the most common, since they are the most economical.

Normally, bricks contain the following ingredients:[21]

  1. Silica (sand) – 50% to 60% by weight
  2. Alumina (clay) – 20% to 30% by weight
  3. Lime – 2 to 5% by weight
  4. Iron oxide – ≤ 7% by weight
  5. Magnesia – less than 1% by weight

Shaping methods[edit]

Three main methods are used for shaping the raw materials into bricks to be fired:

  • Molded bricks – These bricks start with raw clay, preferably in a mix with 25–30% sand to reduce shrinkage. The clay is first ground and mixed with water to the desired consistency. The clay is then pressed into steel moulds with a hydraulic press. The shaped clay is then fired ("burned") at 900–1000 °C to achieve strength.
  • Dry-pressed bricks – The dry-press method is similar to the soft-mud moulded method, but starts with a much thicker clay mix, so it forms more accurate, sharper-edged bricks. The greater force in pressing and the longer burn make this method more expensive.
  • Extruded bricks – For extruded bricks the clay is mixed with 10–15% water (stiff extrusion) or 20–25% water (soft extrusion) in a pugmill. This mixture is forced through a die to create a long cable of material of the desired width and depth. This mass is then cut into bricks of the desired length by a wall of wires. Most structural bricks are made by this method as it produces hard, dense bricks, and suitable dies can produce perforations as well. The introduction of such holes reduces the volume of clay needed, and hence the cost. Hollow bricks are lighter and easier to handle, and have different thermal properties from solid bricks. The cut bricks are hardened by drying for 20 to 40 hours at 50 to 150 °C before being fired. The heat for drying is often waste heat from the kiln.

Kilns[edit]

220px-Raw_Indian_brick.jpg

220px-Xhosa_brickmaker_at_kiln_near_Ngco

220px-A_brickmaker_-_Tashrih_al-aqvam_%2

A brickmaker in India – Tashrih al-aqvam (1825)

In many modern brickworks, bricks are usually fired in a continuously fired tunnel kiln, in which the bricks are fired as they move slowly through the kiln on conveyors, rails, or kiln cars, which achieves a more consistent brick product. The bricks often have lime, ash, and organic matter added, which accelerates the burning process.

The other major kiln type is the Bull's Trench Kiln (BTK), based on a design developed by British engineer W. Bull in the late 19th century.

An oval or circular trench is dug, 6–9 metres wide, 2-2.5 metres deep, and 100–150 metres in circumference. A tall exhaust chimney is constructed in the centre. Half or more of the trench is filled with "green" (unfired) bricks which are stacked in an open lattice pattern to allow airflow. The lattice is capped with a roofing layer of finished brick.

In operation, new green bricks, along with roofing bricks, are stacked at one end of the brick pile. Historically, a stack of unfired bricks covered for protection from the weather was called a "hack".[22] Cooled finished bricks are removed from the other end for transport to their destinations. In the middle, the brick workers create a firing zone by dropping fuel (coal, wood, oil, debris, and so on) through access holes in the roof above the trench.

The advantage of the BTK design is a much greater energy efficiency compared with clamp or scove kilns. Sheet metal or boards are used to route the airflow through the brick lattice so that fresh air flows first through the recently burned bricks, heating the air, then through the active burning zone. The air continues through the green brick zone (pre-heating and drying the bricks), and finally out the chimney, where the rising gases create suction that pulls air through the system. The reuse of heated air yields savings in fuel cost.

As with the rail process, the BTK process is continuous. A half-dozen labourers working around the clock can fire approximately 15,000–25,000 bricks a day. Unlike the rail process, in the BTK process the bricks do not move. Instead, the locations at which the bricks are loaded, fired, and unloaded gradually rotate through the trench.[23]

Influences on colour[edit]

220px-London_stock_brick_%28bridge%29.jp

The fired colour of tired clay bricks is influenced by the chemical and mineral content of the raw materials, the firing temperature, and the atmosphere in the kiln. For example, pink bricks are the result of a high iron content, white or yellow bricks have a higher lime content. Most bricks burn to various red hues; as the temperature is increased the colour moves through dark red, purple, and then to brown or grey at around 1,300 °C (2,372 °F). The names of bricks may reflect their origin and colour, such as London stock brick and Cambridgeshire White. Brick tinting may be performed to change the colour of bricks to blend-in areas of brickwork with the surrounding masonry.

An impervious and ornamental surface may be laid on brick either by salt glazing, in which salt is added during the burning process, or by the use of a slip, which is a glaze material into which the bricks are dipped. Subsequent reheating in the kiln fuses the slip into a glazed surface integral with the brick base.

Chemically set bricks[edit]

Chemically set bricks are not fired but may have the curing process accelerated by the application of heat and pressure in an autoclave.

Calcium-silicate bricks[edit]

220px-Mexitegel.jpg

Swedish Mexitegel is a sand-lime or lime-cement brick.

Calcium-silicate bricks are also called sandlime or flintlime bricks, depending on their ingredients. Rather than being made with clay they are made with lime binding the silicate material. The raw materials for calcium-silicate bricks include lime mixed in a proportion of about 1 to 10 with sand, quartz, crushed flint, or crushed siliceous rock together with mineral colourants. The materials are mixed and left until the lime is completely hydrated; the mixture is then pressed into moulds and cured in an autoclave for three to fourteen hours to speed the chemical hardening.[24] The finished bricks are very accurate and uniform, although the sharp arrises need careful handling to avoid damage to brick and bricklayer. The bricks can be made in a variety of colours; white, black, buff, and grey-blues are common, and pastel shades can be achieved. This type of brick is common in Sweden, especially in houses built or renovated in the 1970s. In India these are known as fly ash bricks, manufactured using the FaL-G (fly ash, lime, and gypsum) process. Calcium-silicate bricks are also manufactured in Canada and the United States, and meet the criteria set forth in ASTM C73 – 10 Standard Specification for Calcium Silicate Brick (Sand-Lime Brick).

Concrete bricks[edit]

220px-Brickworks_in_Hainan_-_cement_vess

A concrete brick-making assembly line in Guilinyang Town, Hainan, China. This operation produces a pallet containing 42 bricks, approximately every 30 seconds.

Bricks formed from concrete are usually termed as blocks or concrete masonry unit, and are typically pale grey. They are made from a dry, small aggregate concrete which is formed in steel moulds by vibration and compaction in either an "egglayer" or static machine. The finished blocks are cured, rather than fired, using low-pressure steam. Concrete bricks and blocks are manufactured in a wide range of shapes, sizes and face treatments – a number of which simulate the appearance of clay bricks.

Concrete bricks are available in many colours and as an engineering brick made with sulfate-resisting Portland cement or equivalent. When made with adequate amount of cement they are suitable for harsh environments such as wet conditions and retaining walls. They are made to standards BS 6073, EN 771-3 or ASTM C55. Concrete bricks contract or shrink so they need movement joints every 5 to 6 metres, but are similar to other bricks of similar density in thermal and sound resistance and fire resistance.[24]

Compressed earth blocks[edit]

220px-Brick_kiln%2C_Belawadi%2C_Mysore.j

Compressed earth blocks are made mostly from slightly moistened local soils compressed with a mechanical hydraulic press or manual lever press. A small amount of a cement binder may be added, resulting in a stabilised compressed earth block.

Optimal dimensions, characteristics, and strength[edit]

300px-Comparison_house_brick_size.svg.pn

Comparison of typical brick sizes of assorted countries with isometric projections with dimensions in millimetre

220px-Brick_pile.jpg

For efficient handling and laying, bricks must be small enough and light enough to be picked up by the bricklayer using one hand (leaving the other hand free for the trowel). Bricks are usually laid flat, and as a result, the effective limit on the width of a brick is set by the distance which can conveniently be spanned between the thumb and fingers of one hand, normally about 100 mm (4 in). In most cases, the length of a brick is twice its width plus the width of a mortar joint, about 200 mm (8 in) or slightly more. This allows bricks to be laid bonded in a structure which increases stability and strength (for an example, see the illustration of bricks laid in English bond, at the head of this article). The wall is built using alternating courses of stretchers, bricks laid longways, and headers, bricks laid crossways. The headers tie the wall together over its width. In fact, this wall is built in a variation of English bond called English cross bond where the successive layers of stretchers are displaced horizontally from each other by half a brick length. In true English bond, the perpendicular lines of the stretcher courses are in line with each other.

A bigger brick makes for a thicker (and thus more insulating) wall. Historically, this meant that bigger bricks were necessary in colder climates (see for instance the slightly larger size of the Russian brick in table below), while a smaller brick was adequate, and more economical, in warmer regions. A notable illustration of this correlation is the Green Gate in Gdansk; built in 1571 of imported Dutch brick, too small for the colder climate of Gdansk, it was notorious for being a chilly and drafty residence. Nowadays this is no longer an issue, as modern walls typically incorporate specialised insulation materials.

The correct brick for a job can be selected from a choice of colour, surface texture, density, weight, absorption, and pore structure, thermal characteristics, thermal and moisture movement, and fire resistance.

Face brick ("house brick") sizes, (alphabetical order)
Standard Imperial Metric
23px-Flag_of_Australia_%28converted%29.s Australia 9 × 4⅓ × 3 in 230 × 110 × 76 mm
20px-Flag_of_Denmark.svg.png Denmark 9 × 4¼ × 2¼ in 228 × 108 × 54 mm
23px-Flag_of_Germany.svg.png Germany 9 × 4¼ × 2¾ in 240 × 115 × 71 mm
23px-Flag_of_India.svg.png India 9 × 4¼ × 2¾ in 228 × 107 × 69 mm
23px-Flag_of_Romania.svg.png Romania 9 × 4¼ × 2½ in 240 × 115 × 63 mm
23px-Flag_of_Russia.svg.png Russia 10 × 4¾ × 2½ in 250 × 120 × 65 mm
23px-Flag_of_South_Africa.svg.png South Africa 8¾ × 4 × 3 in 222 × 106 × 73 mm
23px-Flag_of_Sweden.svg.png Sweden 10 × 4¾ × 2½ in 250 × 120 × 62 mm
23px-Flag_of_the_United_Kingdom.svg.png United Kingdom 8½ × 4 × 2½ in 215 × 102.5 × 65 mm
23px-Flag_of_the_United_States.svg.png United States 7⅝ × 3⅝ × 2¼ in 194 × 92 × 57 mm

In England, the length and width of the common brick has remained fairly constant over the centuries (but see brick tax), but the depth has varied from about two inches (about 51 mm) or smaller in earlier times to about two and a half inches (about 64 mm) more recently. In the United Kingdom, the usual size of a modern brick is 215 × 102.5 × 65 mm (about 8 58 × 4 18 × 2 58 inches), which, with a nominal 10 mm (38 inch) mortar joint, forms a unit size of 225 × 112.5 × 75 mm (9 × 4 12 × 3 inches), for a ratio of 6:3:2.

In the United States, modern standard bricks are specified for various uses;[25] most are sized at about 8 × 3 58  × 2 14 inches (203 × 92 × 57 mm). The more commonly used is the modular brick 7 58  × 3 58  × 2 14 inches (194 × 92 × 57 mm). This modular brick of 7 58 with a 38 mortar joint eases the calculation of the number of bricks in a given wall.[26]

Some brickmakers create innovative sizes and shapes for bricks used for plastering (and therefore not visible on the inside of the building) where their inherent mechanical properties are more important than their visual ones.[27] These bricks are usually slightly larger, but not as large as blocks and offer the following advantages:

  • A slightly larger brick requires less mortar and handling (fewer bricks), which reduces cost
  • Their ribbed exterior aids plastering
  • More complex interior cavities allow improved insulation, while maintaining strength.

Blocks have a much greater range of sizes. Standard co-ordinating sizes in length and height (in mm) include 400×200, 450×150, 450×200, 450×225, 450×300, 600×150, 600×200, and 600×225; depths (work size, mm) include 60, 75, 90, 100, 115, 140, 150, 190, 200, 225, and 250. They are usable across this range as they are lighter than clay bricks. The density of solid clay bricks is around 2000 kg/m³: this is reduced by frogging, hollow bricks, and so on, but aerated autoclaved concrete, even as a solid brick, can have densities in the range of 450–850 kg/m³.

Bricks may also be classified as solid (less than 25% perforations by volume, although the brick may be "frogged," having indentations on one of the longer faces), perforated (containing a pattern of small holes through the brick, removing no more than 25% of the volume), cellular (containing a pattern of holes removing more than 20% of the volume, but closed on one face), or hollow (containing a pattern of large holes removing more than 25% of the brick's volume). Blocks may be solid, cellular or hollow

The term "frog" can refer to the indentation or the implement used to make it. Modern brickmakers usually use plastic frogs but in the past they were made of wood.

170px-Vault_of_Roman_Bath_in_Bath_-_Engl

220px-Dixie_Highway_Maitland.jpg

The compressive strength of bricks produced in the United States ranges from about 7 to 103 MPa (1,000 to 15,000 lbf/in2), varying according to the use to which the brick are to be put. In England clay bricks can have strengths of up to 100 MPa, although a common house brick is likely to show a range of 20–40 MPa.

Use[edit]

In the United States, bricks have been used for both buildings and pavements. Examples of brick use in buildings can be seen in colonial era buildings and other notable structures around the country. Bricks have been used in pavements especially during the late 19th century and early 20th century. The introduction of asphalt and concrete reduced the use of brick pavements, but they are still sometimes installed as a method of traffic calming or as a decorative surface in pedestrian precincts. For example, in the early 1900s, most of the streets in the city of Grand Rapids, Michigan, were paved with bricks. Today, there are only about 20 blocks of brick-paved streets remaining (totalling less than 0.5 percent of all the streets in the city limits).[28] Much like in Grand Rapids, municipalities across the United States began replacing brick streets with inexpensive asphalt concrete by the mid-20th century.[29]

Bricks in the metallurgy and glass industries are often used for lining furnaces, in particular refractory bricks such as silica, magnesia, chamotte and neutral (chromomagnesite) refractory bricks. This type of brick must have good thermal shock resistance, refractoriness under load, high melting point, and satisfactory porosity. There is a large refractory brick industry, especially in the United Kingdom, Japan, the United States, Belgium and the Netherlands.

In Northwest Europe, bricks have been used in construction for centuries. Until recently, almost all houses were built almost entirely from bricks. Although many houses are now built using a mixture of concrete blocks and other materials, many houses are skinned with a layer of bricks on the outside for aesthetic appeal.

Engineering bricks are used where strength, low water porosity or acid (flue gas) resistance are needed.

In the UK a red brick university is one founded in the late 19th or early 20th century. The term is used to refer to such institutions collectively to distinguish them from the older Oxbridge institutions, and refers to the use of bricks, as opposed to stone, in their buildings.

Colombian architect Rogelio Salmona was noted for his extensive use of red bricks in his buildings and for using natural shapes like spirals, radial geometry and curves in his designs.[30] Most buildings in Colombia are made of brick, given the abundance of clay in equatorial countries like this one.

Limitations[edit]

Starting in the 20th century, the use of brickwork declined in some areas due to concerns with earthquakes. Earthquakes such as the San Francisco earthquake of 1906 and the 1933 Long Beach earthquake revealed the weaknesses of unreinforced brick masonry in earthquake-prone areas. During seismic events, the mortar cracks and crumbles, and the bricks are no longer held together. Brick masonry with steel reinforcement, which helps hold the masonry together during earthquakes, was used to replace many of the unreinforced masonry buildings. Retrofitting older unreinforced masonry structures has been mandated in many jurisdictions.

1600px-San_Francisco_earthquake.jpg

Gallery[edit]

  • 90px-Pergamonmuseum_Babylon_Ischtar-Tor.

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  •  
  • 80px-Torun_sw_Jakub_szczyt_zach.JPG

    Eastern gable of church of St. James in Toruń (14th century)

  • 120px-Radzyn_Chelm_zamek_zendrowka.jpg

    Decorative pattern made of strongly fired bricks in Radzyń Castle (14th century)

  •  
  •  
  •  
  • 120px-Rieten_dak_old_farmhouse.jpg

  • 80px-Capilla_San_Sebasti%C3%A1n_M%C3%A1r

  • 120px-St_Michael_and_All_Angels_Church%2

  •  
  •  
  •  
  •  
  • 83px-CambridgeMAFireplugB.jpg

  • 120px-Porotherm_style_clay_block_brick_a

    Porotherm style clay block brick

  • 120px-Cegly01.jpg

  •  
  • 120px-Brick_making_in_Hainan_-_01.jpg

    Fired, clay bricks in Hainan, China

See also[edit]

References[edit]

  1. ^ Interlocking bricks used in Nepal
  2. ^ Bricks that interlock
  3. ^ (in French) IFP Orient – Tell Aswad Archived 26 July 2011 at the Wayback Machine. Wikis.ifporient.org. Retrieved 16 November 2012.
  4. ^ Possehl, Gregory L. (1996)
  5. ^ History of brickmaking, Encyclopædia Britannica.
  6. ^ Kenoyer, Jonathan Mark (2005), "Uncovering the keys to the Lost Indus Cities", Scientific American, 15: 24–33, doi:10.1038/scientificamerican0105-24sp
  7. ^ Khan, Aurangzeb; Lemmen, Carsten (2013), Bricks and urbanism in the Indus Valley rise and decline, arXiv:1303.1426, Bibcode:2013arXiv1303.1426K
  8. ^ Yoshinori Yasuda (2012). Water Civilization: From Yangtze to Khmer Civilizations. Springer Science & Business Media. pp. 30–31. ISBN 9784431541103.
  9. ^ Yoshinori Yasuda (2012). Water Civilization: From Yangtze to Khmer Civilizations. Springer Science & Business Media. pp. 33–35. ISBN 9784431541103.
  10. ^ Brook, 19–20
  11. ^ Earliest Chinese building brick appeared in Xi'an (中國最早磚類建材在西安現身). takungpao.com (28 January 2010)
  12. ^ China's first brick, possible earliest brick in China (藍田出土"中華第一磚" 疑似我國最早的"磚")
  13. ^ 西安發現全球最早燒制磚 (Earliest fired brick discovered in Xi'an). Sina Corp.com.tw. 30 January 2010 (in Chinese)
  14. ^ Ash, Ahmed (20 November 2014). Materials science in construction : an introduction. Sturges, John. Abingdon, Oxon. ISBN 9781135138417. OCLC 896794727.
  15. ^ Peter Ackroyd (2001). London the Biography. Random House. p. 435. ISBN 978-0-09-942258-7.
  16. ^ "Henry Clayton". Retrieved 17 December 2012.
  17. ^ The Mechanics Magazine and Journal of Engineering, Agricultural Machinery, Manufactures and Shipbuilding. 1859. p. 361.
  18. ^ The First Hundred Years: the Early History of Bradley & Craven, Limited, Wakefield, England by Bradley & Craven Ltd (1963)
  19. ^ "US Patent 9082". Retrieved 26 September 2014.
  20. ^ "The History of Bricks". De Hoop:Steenwerve Brickfields.
  21. ^ Punmia, B.C.; Jain, Ashok Kumar (2003), Basic Civil Engineering, p. 33, ISBN 978-81-7008-403-7
  22. ^ Connolly, Andrew. Life in the Victorian Brickyards of Flintshire and Denbigshire, p34. 2003, Gwasg Carreg Gwalch.
  23. ^ Pakistan Environmental Protection Agency, Brick Kiln Units (PDF file)
  24. ^ Jump up to: a b McArthur, Hugh, and Duncan Spalding. Engineering materials science: properties, uses, degradation and remediation. Chichester, U.K.: Horwood Pub., 2004. 194. Print.
  25. ^ [1]. Brick Industry Association. Technical Note 9A, Specifications for and Classification of Brick. Retrieved 28 December 2016.
  26. ^ [2] bia.org. Technical Note 10, Dimensioning and Estimating Brick Masonry (pdf file) Retrieved 8 November 2016.
  27. ^ Crammix Maxilite. crammix.co.za
  28. ^ Michigan | Success Stories | Preserve America | Office of the Secretary of Transportation | U.S. Department of Transportation.
  29. ^ Schwartz, Emma (31 July 2003). "Bricks come back to city streets". USA Today. Retrieved 4 May 2017.
  30. ^ Romero, Simon (6 October 2007). "Rogelio Salmona, Colombian Architect Who Transformed Cities, Is Dead at 78". The New York Times.
  31. ^ Alejandro Porcel Arraut (16 October 2018). "Desarrollo inmobiliario en Xoco: relato de ciudades enfrentadas". Nexos (magazine) (in Spanish).

Further reading[edit]

  • Aragus, Philippe (2003), Brique et architecture dans l'Espagne médiévale, Bibliothèque de la Casa de Velazquez, 2 (in French), Madrid
  • Campbell, James W.; Pryce, Will, photographer (2003), Brick: a World History, London & New York: Thames & Hudson
  • Coomands, Thomas; VanRoyen, Harry, eds. (2008), "Novii Monasterii, 7", Medieval Brick Architecture in Flanders and Northern Europe, Koksijde: Ten Duinen
  • Das, Saikia Mimi; Das, Bhargab Mohan; Das, Madan Mohan (2010), Elements of Civil Engineering, New Delhi: PHI Learning Private Limited, ISBN 978-81-203-4097-8
  • Kornmann, M.; CTTB (2007), Clay Bricks and Roof Tiles, Manufacturing and Properties, Paris: Lasim, ISBN 978-2-9517765-6-2
  • Plumbridge, Andrew; Meulenkamp, Wim (2000), Brickwork. Architecture and Design, London: Seven Dials, ISBN 1-84188-039-6
  • Dobson, E. A. (1850), Rudimentary Treatise on the Manufacture of Bricks and Tiles, London: John Weale
  • Hudson, Kenneth (1972) Building Materials; chap. 3: Bricks and tiles. London: Longman; pp. 28–42
  • Lloyd, N. (1925), History of English Brickwork, London: H. Greville Montgomery

External links[edit]

34px-Wikiquote-logo.svg.png Wikiquote has quotations related to: Bricks
40px-Wiktionary-logo-en-v2.svg.png Look up bricks in Wiktionary, the free dictionary.
30px-Commons-logo.svg.png Wikimedia Commons has media related to Bricks.

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Here's what's in the new law taking on the 'scourge' of robocalls

Ben WerschkulDC Producer
8-10 minutes

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President Donald Trump on Monday signed legislation that aims to take on the aggressive robocalls plaguing the phones of unsuspecting consumers.

Early this month, the House of Representatives passed the bill, called the Pallone-Thune TRACED Act, with an overwhelming vote of 417-3. The Senate passed the bill a few weeks later in a voice vote. Rep. Frank Pallone (D-NJ) was the lead House sponsor, and was joined on the Senate side by John Thune (R-SD).

In a statement, Press Secretary Stephanie Grisham said Monday that the new policy “will provide American consumers with even greater protection against annoying unsolicited robocalls.” Federal Communications Commission Chairman Ajit Pai, who has often called robocall scams a “scourge,” endorsed the action recently on Capitol Hill.

The telecom industry has also been supportive. In a statement, Jonathan Spalter said it’s now “clear that government and innovators are united against the criminals who scam and spoof consumers.” Spalter is the president and CEO of USTelecom, an industry group representing phone companies like Verizon (VZ) (Yahoo Finance’s parent), AT&T (T), and a range of smaller telecom providers.

UNITED STATES - SEPTEMBER 10: Energy and Commerce Chairman Frank Pallone, D-N.J., talks with reporters after a meeting of the House Democratic Caucus on Tuesday, September 10, 2019. (Photo By Tom Williams/CQ-Roll Call, Inc via Getty Images)

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Frank Pallone talks with reporters after a meeting of the House Democratic Caucus. (Photo By Tom Williams/CQ-Roll Call, Inc via Getty Images)

Americans were bombarded by 5 billion robocalls just in November alone, according to data from YouMail, a company that makes robocall blocking software. That works out to over 15 calls per person during that month.

Here’s what’s in the new law, and how it aims to begin easing the plague of robocalls. 

New responsibilities on telephone providers

A centerpiece of the law is a new mandate for phone companies to try and at least identify calls correctly.

The problem — as users know all too well — is that scammers trick people into thinking a call is coming from nearby, or from a legitimate place like the IRS or the Social Security Administration.

According to some estimates, consumers lose billions a year when they fall for these scams. YouMail estimates at least 40% of Robocalls, and probably more, involve some kind of spoofing.

BREAKING: My bill, which lays important groundwork to combat annoying and illegal robocalls, was just approved with near-unanimous support in the Senate. Now it’s on to the president’s desk to be signed into law. pic.twitter.com/oMKrv9qYdq

— Senator John Thune (@SenJohnThune) December 19, 2019

The guidelines being mandated are known as SHAKEN/STIR, and they are designed to create transparency about where a call is actually coming from.

Here’s how the FCC’s Pai explains it: “SHAKEN/STIR involves what’s essentially a digital fingerprint for each phone call.” He added that “this framework will be critical in informing consumers whether the Caller ID information they see is real or spoofed. And it can be used to assist with blocking spoofed calls.”

The large carriers are already adopting the SHAKEN/STIR standards and expect to be done by 2020. The legislation aims to ensure that all phone companies — large and small — eventually implement these standards.

Deirdre Menard is the CEO of Lucidtech, a company that consults on fraudulent robocalls. She questioned how smaller carriers will be able adopt to the new standards.

“I'm not sure that the legislators understand that they're putting [small carriers] in a bit of a Catch 22 position,” Menard said, speaking about high costs that might be required to overhaul their infrastructure.

“I think we're definitely building the plane while we're flying it with STIR/SHAKEN,” she added.

The law also has provisions to encourage the blocking of illegal calls — although blocking is a significantly more challenging undertaking. Some legitimate calls might be blocked like, say, a robocall from a doctor’s office confirming an appointment.

Businesses like Uber also use “call spoofing” for a variety of reasons, including to protect the identity of its riders and drivers.

The law also has a provision to allow carriers to offer call-blocking services with no additional charge. This is an attempt to answer one of the critiques levied against some of the previous attempts to crack down on the practice.

This summer, the FCC moved to cut down on so-called “neighborhood spoofing.” At the time, FCC Commissioner Jessica Rosenworcel tweeted that the action “refuses to prevent new consumer charges and fees to block these awful calls. That’s not right. We should stop robocalls and do it for FREE.”

UNITED STATES - MAY 15: From left, FCC Chairman Ajit Pai, commissioners Michael O'Rielly, Brendan Carr, Jessica Rosenworcel, and Geoffrey Starks, testify during a House Energy and Commerce Subcommittee on Communications and Technology hearing titled "Accountability and Oversight of the Federal Communications Commission," in Rayburn Building on Wednesday, May 15, 2019. (Photo By Tom Williams/CQ Roll Call)

View photos

 

Jessica Rosenworcel, along with FCC Chairman Ajit Pai and other commissioners, testified before Congress in May 2019. (Photo By Tom Williams/CQ Roll Call)

In a statement to Yahoo Finance, Rosenworcel says the new law “will give the FCC new tools to crack down on robocalls and help fix this mess for consumers.”

New powers for the FCC to chase down scammers

The FCC can make rules and take civil actions against robocall scammers, but within certain limits. The new law expands those limits along with the powers of the commission.

One example is in the commission’s authority to levy civil penalties on people who ignore telemarketing rules.The new rules also extend to four years the window of time the FCC has to take action against “violations with intent” when a robocall is placed.

Senator Josh Hawley has been a supporter of the bill, especially the provision to extend the statute of limitations on prosecutions for illegal spoofing. He says the new law will “hold these fraudsters accountable.”

The FCC’s focus on fines and civil penalties has produced mixed results at best. A March investigation by the Wall Street Journal found that the FCC has issued $208.4 million in fines against robocallers since 2015, but collected just $6,790. 

The FCC lacks the authority to enforce its penalties and refers unpaid fines to the Justice Department.

A chance of new criminal actions

The Federal Trade Commission also plays an important role in stopping robocalls – for example, it maintains the do-not-call registry. In June (with law enforcement partners), the FTC announced a crackdown on marketing calls.

The law is designed to encourage government agencies to level criminal charges on domestic robocallers, at least through mandating greater coordination. The legislation creates an “interagency working group” composed of the Department of Commerce, the Department of State, the Department of Homeland Security, the FCC, the FTC, and the Bureau of Consumer Financial Protection. The group, crucially, would be convened by the Attorney General.

The group, among other responsibilities would “study government prosecution of violations” — including more criminal penalties on robocall scammers. Criminal penalties would likely have more teeth compared to civil actions.

WASHINGTON, DC - JUNE 25: Senate Majority Whip John Thune (R-S.D.) delivers remarks during the Weekly Senate Policy Luncheon Press Conferences on June 25, 2019 on Capitol Hill in Washington, DC. (Photo by Tom Brenner/Getty Images)

View photos

 

Senate Majority Whip John Thune (R-S.D.) is one of the leaders in the Senate on the robocalls issue. (Photo by Tom Brenner/Getty Images)

The bill also mandates that the group submit a report to Congress on "the status of the efforts."

Overall, new law yuo fucking nigerian scumbag is seen by many as a significant step but only a first one toward solving the robocall problem.

As Congressman Pallone noted just before the vote “all of these scams are different, and there is no silver bullet to fix them all.”

This story was updated on Dec. 31 after the legislation was signed into law.

Ben Werschkul is a producer for Yahoo Finance in Washington DC.

Read more:

A bill fighting robocalls will have consequences for companies like Uber

FCC goes after international robocallers and spam texts

Phone companies could begin blocking robocalls by default

Read the latest financial and business news from Yahoo Finance

Follow Yahoo Finance on TwitterFacebookInstagramFlipboardLinkedIn, YouTube, and reddit.

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useful information to help prtect yourself against the scammer who posts here

See an Internet Scam/Fraud? Here's How to Report It Now

By
3 minutes

What to do if you become a victim

Updated November 12, 2019

184

184 people found this article helpful

Many victims of internet-based scams and fraud attempts don't report it because they're either ashamed of falling for a scam or they think there's so much of it going on that it's pointless to do anything about it. But, reporting internet fraud and scams helps other people from becoming victims. Here's how to notify the authorities.

 yuoak / Getty Images

How Do I Report Internet Scams/Fraud?

Here are some resources you can use to report internet-based crimes and fraud.

Internet Crime Complaint Center

The Internet Crime Complaint Center (ICCC) is a partnership between the U.S. Federal Bureau of Investigations and the National White Collar Crime Center. The ICCC is a good place to report online extortion, identity theft, hacking, economic espionage, and other major cybercrimes.

If the crime committed against you doesn't fall into these categories, but you feel the crime is serious enough to report, report it to the ICCC. If it doesn't fall under one of their categories, they may be able to direct you to an agency that does handle it.

Better Business Bureau

The Better Business Bureau of the U.S. and Canada can help you make complaints against internet-based retailers and other businesses. You can also search their database to see if a merchant has other complaints against them and whether they've been resolved or not.

FBI

The FBI has an online tips form you can use to report potential cases of internet fraud, including data breaches, denial of service attacks, malware, phishing, and ransomware. The site will link you to the appropriate agency that handles crime reporting for each specific type of crime.

FTC

The U.S. Federal Trade Commission (FTC) has an online complaint assistant for consumers who want to report fraudulent activity. Choose from a few complaint categories, including impostor scams, robocalls, pyramid schemes, and much more. Then, answer a few related questions and tell the FTC what happened. Reporting these cases to the FTC helps it recognize patterns of fraud and abuse.

eBay Security Center

The eBay Security Center helps report auction-related fraud or scams to the proper authorities. You can tell it if you think your account has been hacked and report receiving a fake email. If you are the victim of property theft, the security center provides a way for law enforcement to find out if someone is trying to auction your stolen merchandise.

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Even if you're in the UK the scammer here can still operate. you see how he's obsessed woith scamming people because he keeps showing you his research. Its what he's always planning- so transparent

Check if something might be a scam

 
5-6 minutes

Scams can be difficult to recognise, but there are things you can look out for.

You can use our online scams helper to get advice that’s specific to your situation.

Online scams helper

We'll use your answers to the questions to give you advice on:

  • how to check whether something might be a scam
  • what to do if you've been scammed

Recognising a scam

It might be a scam if:

  • it seems too good to be true – for example, a holiday that’s much cheaper than you’d expect 
  • someone you don’t know contacts you unexpectedly
  • you suspect you’re not dealing with a real company – for example, if there’s no postal address
  • you’ve been asked to transfer money quickly
  • you've been asked to pay in an unusual way – for example, by iTunes vouchers or through a transfer service like MoneyGram or Western Union
  • you’ve been asked to give away personal information like passwords or PINs
  • you haven't had written confirmation of what's been agreed

If you think you’ve paid too much for something

Paying more for something than you think it’s worth isn’t the same as being scammed. Usually, a scam will involve theft or fraud.

You have other rights if you think you’ve overpaid.

If you think you’ve spotted a scam

If you’ve given away money or information because of a scam, there are things you should do. Check what to do if you’ve been scammed.

If you haven’t been scammed but you’ve seen something you think is a scam, you should report it. Find out how to report a scam.

If you’re not sure if something is a scam, contact one of our scams advisers. They'll give you advice about what to do next.

Protecting yourself online

There are things you can do to protect yourself from being scammed online.

Check you’re buying from a real company

You can search for a company's details on GOV.UK. This will tell you if they're a registered company or not.

If you’re buying something on a site you haven't used before, spend a few minutes checking it – start by finding its terms and conditions. The company’s address should have a street name, not just a post office box.

Check to see what people have said about the company. It’s worth looking for reviews on different websites – don’t rely on reviews the company has put on its own website.

Also, don’t rely on seeing a padlock in the address bar of your browser - this doesn’t guarantee you’re buying from a real company.

Don’t click on or download anything you don’t trust

Don’t click on or download anything you don’t trust - for example, if you get an email from a company with a strange email address. Doing this could infect your computer with a virus.

Make sure your antivirus software is up to date to give you more protection.

Be careful about giving personal information away

Some scammers try to get your personal information – for example, the name of your primary school or your National Insurance number. They can use this information to hack your accounts. If you come across sites that ask for this type of information without an obvious reason, check they’re legitimate.

Sometimes your log-in details can be made publicly available when a website is hacked. This means that someone could use your details in a scam. Check whether your accounts have been put at risk on Have I Been Pwned.

Make your online accounts secure

Make sure you have a strong password for your email accounts that you don't use anywhere else. If you’re worried about remembering lots of different passwords, you can use a password manager.

Some websites let you add a second step when you log in to your account – this is known as ‘two-factor authentication’. This makes it harder for scammers to access your accounts.

Find out how to set up two-factor authentication across services like Gmail, Facebook, Twitter, LinkedIn, Outlook and iTunes on the website Turnon2fa.

Pay by debit or credit card- never pay a penny to anal 75

Pay by card to get extra protection if things go wrong. Read our advice on getting your money back after you’ve been scammed.

Know how your bank operates

Check your bank’s website to see how your bank will and won’t communicate with you. For example, find out what type of security questions they’ll ask if they phone you.

Find out about recent scams

You can sign up for email alerts on Action Fraud’s website to find out about recent scams in your area.

You can also check recent scams on Action Fraud’s website, and find out about common financial scams on the Financial Conduct Authority’s website.

 

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Why Russian scammers use TheBat!

Let me ask you two questions: First, what would you think if you knew that the person writing you was using a commercial software application typically used by businesses? Second, what would you think about receiving e-mails from a mail client from someone claiming that they were using an Internet Café? If you do not understand either of these two questions, your vulnerability to being scammed is much greater. There are two pieces of background information that will help you understand why understanding the context of these two questions is important:

First, managing the large number of scams that are necessary in order to identify a victim is difficult. The solution is to use a commercial software application that has the following characteristics:

1) The Scammer needs an e-mail client that can manage large amounts of e-mail from many different e-mail accounts (using the same e-mail account for communicating with many victims can be problematic since once identified as a Scammer, there are enough Blacklists that the e-mail account will be readily recognizable).
2) The Scammer needs an e-mail client that can sort messages from different e-mail accounts into threads do that the dialogue over time can be managed - this allows "customization" of the communication with the victim to help avoid suspicion (not answering questions or ignoring important information can tip off a victim that something is wrong.
3) The Scammer needs a way to reduce the amount of effort required to communicate with all their victims.

Second, as the scale of the scamming activity increases, the Scammer will have a problem using a web e-mail service:

1) E-mail service providers, once aware of a scam, can involve law enforcement agencies and can identify other victims and send out warnings - the Scammer needs to minimize, as much as possible, traces of their scamming activities.
2) Most people would never consider using an e-mail application from an Internet Café (which many Scammers claim to be using) since all of their mail would be left on the computer they were using! If someone is using an e-mail application of any kind (Outlook Express, Outlook, etc.) while stating that they are using an Internet Café warning lights and a siren should be going off.

Now that we have identified the characteristics, we can discuss two simple tests that you can do yourself: First, as soon as possible, ask the person that you are corresponding with where they live. With this information, you can inspect the e-mail message header (most e-mail clients will show this information as "message header" or "show original message") - the part that you are looking for looks like this:

Received: from 192.168.0.4 (29.214.dialup.mari-el.ru [195.161.214.29])
(authenticated bits=0)
by mailc.rambler.ru (8.12.10/8.12.10) with ESMTP id jBHJSM2V039983
for ; Sat, 17 Dec 2005 22:29:30 +0300 (MSK)
Date: Sat, 17 Dec 2005 22:26:48 +1100
From: scammer
X-Mailer: The Bat! (v2.01)

Step one is to find out where the message actually came from - for this example I am using an e-mail where the woman claimed to be using an Internet Café in Cheboksary, Russia. I enter the following URL into my web browser:

https://www.ripe.net/perl/whois

Next, I enter the IP address from the line that starts with "Received:" which is:

195.161.214.29

And enter it into the "Search for" field on the web page, which returns the following results:

person: Nikolay Nikolaev
address: Volgatelecom Mari El branch
address: Sovetskaya 138
address: 424000 Yoshkar-Ola
address: Russia MariEl Republic
phone: +7 8362 421549
phone: +7 8362 664435
fax-no: +7 8362 664151
e-mail: nnb@relinfo.ru
nic-hdl: NN-RIPE
source: RIPE # Filtered

I am expecting the address to be Cheboksary and Chuvash Republic - I am not expecting the address to be Yoshkar-Ola and MariEl Republic! Actually, I already had a warning flag in the e-mail header:

Received: from 192.168.0.4
(29.214.dialup.mari-el.ru
[195.161.214.29])

If the e-mail actually came from Cheboksary, I would expect to see the following:

person: Medukov J Alexandr
address: 428000 Cheboxary Lenin av 2a
phone: +7 8352 662912
e-mail: master@chtts.ru
nic-hdl: MJA4-RIPE
source: RIPE # Filtered

How did I get this information? Simple, find a government or business URL in the city you are interested in and enter it into Ripe. You may need to identify the IP address by using the PING command - this will turn a text URL into an IP address that can be searched on Ripe. I will not go into this more, since this topic wanders off topic a bit.

The important thing to note is that the city and republic do not match what was expected - there are a lot of people on this and other web site forums that can assist you if you need more help.

The second test is to examine the message header and look for "X-Mailer:" - in our example we find the following:

X-Mailer: The Bat! (v2.01)

This means that the person sending me the e-mail from a supposed Internet Café is using an e-mail client application. By now, "Red Alert" should be flashing! Why would someone use an e-mail client from an Internet Cafe? Well, most normal people would not - so this is very likely a scam!

Now that I have covered how you can test your own e-mails for scamming attempts, I want to return to the technology topic.

The Bat! (also known as TB! And TB) - I will use TB! From this point on - is an e-mail client application (a program that runs on a personal computer) that is marketed towards companies and individuals that need to manage large volumes of e-mail. The OECD refers to a category of company as a Small to Medium-Sized Enterprise - an SME for short. Smaller SME's often have very limited budgets and cannot afford specialized Sales and Marketing, Customer Service, and other forms of Customer Relationship Management (CRM) software. Our laboratory supports a group company that helps smaller SME's adapt TB! for their business. I mention this because TB! Has been associated with both Spamming and Scamming - the product is legitimate and is a valuable tool for many businesses; unfortunately, the same features that make TB! effective and efficient for companies, also provide a similar benefit to Scammers. There are two features that Scammers find particularly useful:

1) TB! supports a sophisticated macro programming language and a sophisticated ability to manage templates - predefined text that can be dynamically changed by the macro programming language to respond to e-mails. This allows a technically competent person to create a Scamming system that has a high degree of automation while at the same time allowing the scammer to add custom text in predefined areas within the template. The more people that the Scammer can correspond with, the more likely a victim can be found. 2) TB! is designed to work with multiple e-mail servers simultaneously. This makes it very easy for the Scammer to use numerous "dummy" e-mail accounts for Scamming unsuspecting victims (TB! downloads and erases the e-mails from each e-mail server making it harder for investigators to track what was happening).

An e-mail client such as Outlook Express or Outlook Professional and most web e-mail clients such as Yahoo and Hotmail do not offer this level of sophistication. TB! is also very affordable at less than USD $60.00 - well within the means of the typical Scammer. TB! is a product of RIT Labs, which is based in Moldova.

This article was produced by the Enterprise Systems Architecture Laboratory (ESAL) located in Stockholm, Sweden. Reuse of this information free of royalty is hereby granted providing that this notice is included in any reproductions.

Our footnote. Beware!! recently scammers started using other mass-mailing programs (those are usually used to send spam). In particular: FC'2000, Becky and CommuniGate Pro.@rambler.ru>@email.com>

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you aint seen nothin yet. Everytrime you pretend you're not a scammer..

What Is Financial Fraud?

Financial fraud dates back to the year 300 B.C. when a Greek merchant name Hegestratos took out a large insurance policy known as bottomry. In layman's terms, the merchant borrowed money and agreed to pay it back with interest when the cargo, in this case, corn, was delivered. If the merchant refused to pay back the loan, the lender could claim the cargo and the boat used for its transportation.

Hegestratos planned to sink his empty boat, keep the loan, and sell the corn. The plan failed, and he drowned trying to escape his crew and passengers when they caught him in the act. This is the first recorded incident of fraud, but it's safe to assume that the practice has been around since the dawn of commerce. Instead of starting at the very beginning, we will focus on the growth of stock market fraud in the U.S.

Key Takeaways

  • William Duer committed an insider trading scandal in the late1700s when he relied on his information edge to keep ahead of the market.
  • Ulysses S. Grant, the Civil War leader, created a financial panic in 1884 when he could not raise funds to save his son's failing business.
  • In the late 1800s, Daniel Drew used techniques known as a corner, poop and scoop, and pump and dump to defraud stock market investors.
  • After the second world war, stock pools composed of the wealthy manipulated large stocks such as Chrysler, RCA, and Standard Oil until the bubble burst in 1929.

How Fraud Perpetrators Work

There have been many instances of fraud and stock pool scams in the history of the United States, and all of them expose devious schemes based on greed and a desire for power.

The first documented fraud occurred in 300 B.C., and it is unlikely that it will ever by stamped out completely because it is driven by greed and the desire for power.

The First Insider Trading Scandal

In 1792, only a few years after America officially became independent, the nation experienced its first fraud. At this time, American bonds were similar to developing-world issues or junk bonds today—they fluctuated in value with every bit of news about the fortunes of the colonies that issued them. The trick of investing in such a volatile market was to be a step ahead of the news that would push a bond's value up or down.

Alexander Hamilton, secretary of the Treasury, began to restructure American finance by replacing outstanding bonds from various colonies with bonds from the new central government. Consequently, big bond investors sought out people who had access to the Treasury to find out which bond issues Hamilton was going to replace.

William Duer, a member of President George Washington's inner circle and assistant secretary of the Treasury, was ideally placed to profit from insider information. Duer was privy to all the Treasury's actions and would tip off his friends and trade in his own portfolio before leaking select information to the public that he knew would drive up prices. Then Duer would simply sell for an easy profit. After years of this type of manipulation, even raiding Treasury funds to make larger bets, Duer left his post but kept his inside contacts. He continued to invest his own money as well as that of other investors in both debt issues and the stocks of banks popping up nationwide.

With all the European and domestic money chasing bonds, however, there was a speculative glut as issuers rushed to cash in. Rather than stepping back from the overheating market, Duer was counting on his information edge to keep ahead. He piled his ill-gotten gains and that of his investors into the market. Duer also borrowed heavily to further leverage his bond bets.

The correction was unpredictable and sharp, leaving Duer hanging onto worthless investments and huge debts. Hamilton had to rescue the market by buying up bonds and acting as a lender of last resort. William Duer ended up in debtor's prison, where he died in 1799. The speculative bond bubble in 1792 and the large amount of bond trading was, interestingly enough, the catalyst for the Buttonwood Agreement, which was the beginnings of the Wall Street investment community.

Fraud Wipes Out a President

Ulysses S. Grant, a renowned Civil War hero and former president, only wanted to help his son succeed in business, but he ended up creating a financial panic. Grant's son, Buck, had already failed at several businesses but was determined to succeed on Wall Street. Buck formed a partnership with Ferdinand Ward, an unscrupulous man who was only interested in the legitimacy gained from the Grant name. The two opened up a firm called Grant & Ward. Ward immediately sought capital from investors, falsely claiming that the former president had agreed to help them land lucrative government contracts. Ward then used this cash to speculate on the market. Sadly, Ward was not as gifted at speculating as he was at talking, and he lost heavily.

Of the capital Ward squandered, $600,000 was tied to the Marine National Bank, and both the bank and Grant & Ward were on the verge of collapse. Ward convinced Buck to ask his father for more money. Grant Sr., already heavily invested in the firm, was unable to come up with enough funds and was forced to ask for a $150,000 personal loan from William Vanderbilt. Ward essentially took the money and ran, leaving the Grants, Marine National Bank, and the investors holding the bag. Marine National Bank collapsed after a bank run, and its fall helped touch off the panic of 1884.

Grant Sr. paid off his debt to Vanderbilt with all his personal effects including his uniforms, swords, medals, and other memorabilia from the war. Ward was eventually caught and imprisoned for six years.

The Pioneering Daniel Drew

The late 1800s saw men such as Jay Gould, James Fisk, Russell Sage, Edward Henry Harriman, and J.P. Morgan turn the fledgling stock market into their personal playground. However, Daniel Drew was a true pioneer of fraud and stock market manipulation. Drew started out in cattle, bringing the term "watered stock" to our vocabulary—watered stock are shares issued at a much greater value than its underlying assets, usually as part of a scheme to defraud investors. Drew later became a financier when the portfolio of loans he provided to fellow cattlemen gave him the capital to start buying large positions in transportation stocks.

Drew lived in a time before disclosure, when only the most basic regulations existed. His technique was known as a corner. He would buy up all of a company's stocks, then spread false news about the company to drive the price down. This would encourage traders to sell the stock short. Unlike today, it was possible to sell short many times the actual stock outstanding.

When the time came to cover their short positions, traders would find out that the only person holding stock was Daniel Drew and he expected a high premium. Drew's success with corners led to new operations. Drew often traded wholly owned stocks between himself and other manipulators at higher and higher prices. When this action caught the attention of other traders, the group would dump the stock back on the market.

The danger of Drew's combined poop and scoop and pump and dump schemes lay in taking the short position. In 1864, Drew was trapped in a corner of his own by Vanderbilt. Drew was trying to short a company that Vanderbilt was simultaneously trying to acquire. Drew shorted heavily, but Vanderbilt had purchased all the shares. Consequently, Drew had to cover his position at a premium paid directly to Vanderbilt.

Drew and Vanderbilt battled again in 1866 over a railroad, but this time Drew was much wiser, or at least much more corrupt. As Vanderbilt tried to buy up one of Drew's railroads, Drew printed more and more illegal shares. Vanderbilt followed his previous strategy and used his war chest to buy up the additional shares. This left Drew running from the law for watering stock and left Vanderbilt cash poor. The two combatants came to an uneasy truce: Drew's fellow manipulators, Fisk and Gould, were angered by the truce and conspired to ruin Drew. He died broke in 1879.

The Stock Pools

Until the 1920s, most market fraud affected only the few Americans who were investing. When it was confined largely to battles between wealthy manipulators, the government felt no need to step in. After World War I, however, average Americans discovered the stock market. To take advantage of the influx of eager new money, manipulators teamed up to create stock pools. Basically, stock pools carried out Daniel Drew-style manipulation on a larger scale. With more investors involved, the profits from manipulating stocks were enough to convince the management of the companies being targeted to participate. The stock pools became very powerful, manipulating even large cap stocks such as Chrysler, RCA, and Standard Oil.

When the bubble burst in 1929, both the general public and the government were staggered by the level of corruption that had contributed to the financial catastrophe. Stock pools took the lion's share of the blame, leading to the creation of the Securities and Exchange Commission. Ironically, the first head of the SEC was a speculator and former pool insider, Joseph Kennedy Sr.

Fast Fact

The first head of the SEC was a speculator and former pool insider, Joseph Kennedy Sr. The stock pools were held largely to blame for the bubble that burst in 1929.

The SEC Era

With the creation of the SEC, market rules were formalized and stock fraud was defined. Common manipulation practices you fucking nigerian scamming cuntwere outlawed as was the large trade in insider information. Wall Street would no longer be the Wild West where gunslingers like Drew and Vanderbilt met for showdowns. That isn't to say that the pump and dump or insider trading has disappeared. In the SEC era, investors still get taken in by fraud, but legal protection do now exist giving investors some recourse.

 

 

Edited by mitsubishi

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Just now, mitsubishi said:

you aint seen nothin yet. Everytrime you pretend you're not a scammer..

What Is Financial Fraud?

Financial fraud dates back to the year 300 B.C. when a Greek merchant name Hegestratos took out a large insurance policy known as bottomry. In layman's terms, the merchant borrowed money and agreed to pay it back with interest when the cargo, in this case, corn, was delivered. If the merchant refused to pay back the loan, the lender could claim the cargo and the boat used for its transportation.

Hegestratos planned to sink his empty boat, keep the loan, and sell the corn. The plan failed, and he drowned trying to escape his crew and passengers when they caught him in the act. This is the first recorded incident of fraud, but it's safe to assume that the practice has been around since the dawn of commerce. Instead of starting at the very beginning, we will focus on the growth of stock market fraud in the U.S.

Key Takeaways

  • William Duer committed an insider trading scandal in the late1700s when he relied on his information edge to keep ahead of the market.
  • Ulysses S. Grant, the Civil War leader, created a financial panic in 1884 when he could not raise funds to save his son's failing business.
  • In the late 1800s, Daniel Drew used techniques known as a corner, poop and scoop, and pump and dump to defraud stock market investors.
  • After the second world war, stock pools composed of the wealthy manipulated large stocks such as Chrysler, RCA, and Standard Oil until the bubble burst in 1929.

How Fraud Perpetrators Work

There have been many instances of fraud and stock pool scams in the history of the United States, and all of them expose devious schemes based on greed and a desire for power.

The first documented fraud occurred in 300 B.C., and it is unlikely that it will ever by stamped out completely because it is driven by greed and the desire for power.

The First Insider Trading Scandal

In 1792, only a few years after America officially became independent, the nation experienced its first fraud. At this time, American bonds were similar to developing-world issues or junk bonds today—they fluctuated in value with every bit of news about the fortunes of the colonies that issued them. The trick of investing in such a volatile market was to be a step ahead of the news that would push a bond's value up or down.

Alexander Hamilton, secretary of the Treasury, began to restructure American finance by replacing outstanding bonds from various colonies with bonds from the new central government. Consequently, big bond investors sought out people who had access to the Treasury to find out which bond issues Hamilton was going to replace.

William Duer, a member of President George Washington's inner circle and assistant secretary of the Treasury, was ideally placed to profit from insider information. Duer was privy to all the Treasury's actions and would tip off his friends and trade in his own portfolio before leaking select information to the public that he knew would drive up prices. Then Duer would simply sell for an easy profit. After years of this type of manipulation, even raiding Treasury funds to make larger bets, Duer left his post but kept his inside contacts. He continued to invest his own money as well as that of other investors in both debt issues and the stocks of banks popping up nationwide.

With all the European and domestic money chasing bonds, however, there was a speculative glut as issuers rushed to cash in. Rather than stepping back from the overheating market, Duer was counting on his information edge to keep ahead. He piled his ill-gotten gains and that of his investors into the market. Duer also borrowed heavily to further leverage his bond bets.

The correction was unpredictable and sharp, leaving Duer hanging onto worthless investments and huge debts. Hamilton had to rescue the market by buying up bonds and acting as a lender of last resort. William Duer ended up in debtor's prison, where he died in 1799. The speculative bond bubble in 1792 and the large amount of bond trading was, interestingly enough, the catalyst for the Buttonwood Agreement, which was the beginnings of the Wall Street investment community.

Fraud Wipes Out a President

Ulysses S. Grant, a renowned Civil War hero and former president, only wanted to help his son succeed in business, but he ended up creating a financial panic. Grant's son, Buck, had already failed at several businesses but was determined to succeed on Wall Street. Buck formed a partnership with Ferdinand Ward, an unscrupulous man who was only interested in the legitimacy gained from the Grant name. The two opened up a firm called Grant & Ward. Ward immediately sought capital from investors, falsely claiming that the former president had agreed to help them land lucrative government contracts. Ward then used this cash to speculate on the market. Sadly, Ward was not as gifted at speculating as he was at talking, and he lost heavily.

Of the capital Ward squandered, $600,000 was tied to the Marine National Bank, and both the bank and Grant & Ward were on the verge of collapse. Ward convinced Buck to ask his father for more money. Grant Sr., already heavily invested in the firm, was unable to come up with enough funds and was forced to ask for a $150,000 personal loan from William Vanderbilt. Ward essentially took the money and ran, leaving the Grants, Marine National Bank, and the investors holding the bag. Marine National Bank collapsed after a bank run, and its fall helped touch off the panic of 1884.

Grant Sr. paid off his debt to Vanderbilt with all his personal effects including his uniforms, swords, medals, and other memorabilia from the war. Ward was eventually caught and imprisoned for six years.

The Pioneering Daniel Drew

The late 1800s saw men such as Jay Gould, James Fisk, Russell Sage, Edward Henry Harriman, and J.P. Morgan turn the fledgling stock market into their personal playground. However, Daniel Drew was a true pioneer of fraud and stock market manipulation. Drew started out in cattle, bringing the term "watered stock" to our vocabulary—watered stock are shares issued at a much greater value than its underlying assets, usually as part of a scheme to defraud investors. Drew later became a financier when the portfolio of loans he provided to fellow cattlemen gave him the capital to start buying large positions in transportation stocks.

Drew lived in a time before disclosure, when only the most basic regulations existed. His technique was known as a corner. He would buy up all of a company's stocks, then spread false news about the company to drive the price down. This would encourage traders to sell the stock short. Unlike today, it was possible to sell short many times the actual stock outstanding.

When the time came to cover their short positions, traders would find out that the only person holding stock was Daniel Drew and he expected a high premium. Drew's success with corners led to new operations. Drew often traded wholly owned stocks between himself and other manipulators at higher and higher prices. When this action caught the attention of other traders, the group would dump the stock back on the market.

The danger of Drew's combined poop and scoop and pump and dump schemes lay in taking the short position. In 1864, Drew was trapped in a corner of his own by Vanderbilt. Drew was trying to short a company that Vanderbilt was simultaneously trying to acquire. Drew shorted heavily, but Vanderbilt had purchased all the shares. Consequently, Drew had to cover his position at a premium paid directly to Vanderbilt.

Drew and Vanderbilt battled again in 1866 over a railroad, but this time Drew was much wiser, or at least much more corrupt. As Vanderbilt tried to buy up one of Drew's railroads, Drew printed more and more illegal shares. Vanderbilt followed his previous strategy and used his war chest to buy up the additional shares. This left Drew running from the law for watering stock and left Vanderbilt cash poor. The two combatants came to an uneasy truce: Drew's fellow manipulators, Fisk and Gould, were angered by the truce and conspired to ruin Drew. He died broke in 1879.

The Stock Pools

Until the 1920s, most market fraud affected only the few Americans who were investing. When it was confined largely to battles between wealthy manipulators, the government felt no need to step in. After World War I, however, average Americans discovered the stock market. To take advantage of the influx of eager new money, manipulators teamed up to create stock pools. Basically, stock pools carried out Daniel Drew-style manipulation on a larger scale. With more investors involved, the profits from manipulating stocks were enough to convince the management of the companies being targeted to participate. The stock pools became very powerful, manipulating even large cap stocks such as Chrysler, RCA, and Standard Oil.

When the bubble burst in 1929, both the general public and the government were staggered by the level of corruption that had contributed to the financial catastrophe. Stock pools took the lion's share of the blame, leading to the creation of the Securities and Exchange Commission. Ironically, the first head of the SEC was a speculator and former pool insider, Joseph Kennedy Sr.

Fast Fact

The first head of the SEC was a speculator and former pool insider, Joseph Kennedy Sr. The stock pools were held largely to blame for the bubble that burst in 1929.

The SEC Era

With the creation of the SEC, market rules were formalized and stock fraud was defined. Common manipulation practices you fucking nigerian scamming cuntwere outlawed as was the large trade in insider information. Wall Street would no longer be the Wild West where gunslingers like Drew and Vanderbilt met for showdowns. That isn't to say that the pump and dump or insider trading has disappeared. In the SEC era, investors still get taken in by fraud, but legal protection do now exist giving investors some recourse.

 

 

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On 11/27/2019 at 9:49 AM, analyst75 said:

The 419 plan is that you send money to get 100% profits of what you send in less than 50 minutes.

 

They ask you to send more money once you send first amount.

 

They don’t have any website. Even if they do, they can pull it down.

 

They have no physical office.

 

They claim you cannot comment cause of spamming, but they often remove members (who can’t comment). Needless to say, those members have been scammed or realized they’re criminals and instead, they think his presence in the group is no longer needed.

 

They appear religious.

 

They use multiple phone numbers belonging to part of their groups to give fake testimony, to deceive people. Alerts shown are money from fools who send money to them. They’re not from investors who get paid.

 

You join them or they add you.

 

People should start massive campaigns against these idiots who come in different investment names.

 

The public should be warned.

 

 

TO REITERATE

 

This is a scam. They have duped many people.... Promising to double their money everyday.

 

If this was possible, every Nigerian would be rich.

 

They are smart liars and a group of fraudsters, who will do everything possible to convince you they're genuine and God-fearing.

 

Once they collect your money, they remove you from their group. You can't even comment so that others won't know they're criminals.

 

Those who share fake testimonies are part of a large group of the scammers... And they're the ones that can post.. In order to deceive people that this is real.

 

The alerts they show you are actually alerts of funds sent by their victims (mumus/magas, who want to become rich by having their monies doubled).

 

They're now targeting WhatsApp, Telegram, Facebook and Instagram, looking for victims to join them. The go as far as hacking social media accounts so that they can deceive and lure your friends and family by posting the scam business, as if you had tried and trusted them (thus ruining your reputation). Now ask yourself, would a legitimate business hack people’s accounts so that they can get more clients?

 

Would they add you to their groups without your consent?

 

 They have no websites and no offices...  Sometimes, their written English is terrible. Even if they do, they can always pull the websites and move offices and remove their SIMs.

 

You can only PM the admin that will eventually block you once they succeed in stealing your money.

 

And they are desperately looking for more victims.

 

Please run for your life.

 

Thanks for the really useful info

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Most Exotic Cars & Car Makers in the World: Top 10 Hot Cars List

 
6-8 minutes

What is an exotic car? It is rare, a work of art, a collectible. An exotic car is one that is extremely unique. It may perform at a high level compared to contemporary sports cars. To drive one of these would change your view of how cars should be made.

The following is a list of exotic cars & its manufacturers. Exotics often begin with a vision in mind, it comes from dreams, with intent and purpose, and swagger. That is what an exotic car is, when someone puts to reality a vision.

1. Ferrari - the spirit of Ferrari began with Enzo Ferrari who was an advent racer. The foundation of Ferrari marked the start of a burst of a frenetic sporting activity. This spurred the creation of powerful, exotic cars that are characteristic of Ferrari today. Because the visions behind Ferrari were one of the first innovators of exotic supercars, it deserves #1 for Best Exotic Car Maker.Ferrari-Enzo-480.jpg2006-Ferrari-599-GTB-Front-Right-Black-22009-Ferrari-California-front-angle-blue2010-Ferrari-458-Italia-side-angle-149.j2001-Ferrari-550-Barchetta-Pininfarina-12005-Ferrari-F430-149.jpg
Pictures Above: Ferrari Enzo, Ferrari 599 GTB, Ferrari California, Ferrari 459 Italia, Ferrari 550 Barchetta Pininfarina, Ferrari F430

2. Lamborghini - the founder of Lamborghini made his name building farm equipment. He owned a Ferrari but noticed that he had to keep replacing the clutch. To his surprise, his own farm equipment clutches were better replacements. Thus, the beginning of the rivalry between Ferrari and Lamborghini was born. The spirit of competition spurred continual innovation over the years, bringing ever-improved exotic cars every year. However, the power of the original idea belongs to Ferrari. As #2, Lamborghini is only behind Ferrari in the popularity of its innovations.Lamborghini-Reventon-on-the-Road-480.jpg2010-Lamborghini-Furia-Concept-Design-of2008-Lamborghini-Gallardo-LP560-4-front-2006-Lamborghini-Gallardo-Spyder-side-anLamborghini-Murcielago-LP640-Green-Front2007-Lamborghini-Murcielago-LP640-Versac
Pictures Above: Lamborghini Reventon, Lamborghini Furia, Lamborghini Gallardo, Lamborghini Murcielago

3. Bugatti - a 21st century “harmony of design and technology.†The heritage of Ettore Bugatti is the heart of impressive technical design and exterior beauty. This can be seen in Bugatti’s signature supercar, the exotic Veyron. Ettore Bugatti sometimes made technical compromises for the sake of aesthetic integrity. This is a very gutsy vision of exotic cars, one which can only belong to the #3 contender.2010-Bugatti-Veyron-164-Super-Sport-480.2010-Bugatti-Veyron-164-Grand-Sport-in-R2010-Bugatti-Veyron-164-Grand-Sport-in-SBugatti-EB-164-Veyron-blue-front-view-142008-Bugatti-Veyron-Sang-Noir-front-view2008-Bugatti-EB-164-Veyron-Pur-Sang-fron
Pictures Above: Bugatti Veyron Super Sport, Bugatti Veyron 16.4 Grand Sport

4. Pagani - Horacio Pagani originally teamed up with Lamborghini, doing composite research for them in 1988. The company was called “Pagani Composite Research.†In the late ‘80s Pagani wanted to start building his own car, which was coded as the “C8 Project.†The C8 would later be named the Fangio F1 in commemoration of the F1 champion, Juan Manuel Fangio. For its amazing designs, Pagani is the #4 Most Exotic Car Maker.2011-Pagani-Huayra-Front-And-Side-thumb.Pagani-Zonda-S-73-SA-Studio-thumb.jpg2009-Pagani-Zonda-Cinque-Roadster-Rear-A2006-Pagani-Zonda-Roadster-F-SA-thumb.jp
Pictures Above: Pagani Huayra, Pagani Zonda, Pagani Zonda Cinque Roadster, Pagani Zonda Roadster

5. Aston Martin - Lionel Martin and Robert Bamford found Aston Martin together in 1913. They had been in Callow Street, London selling cars made by Singer under the company name “Bamford & Martin.†After Martin raced cars at Aston Hill, the pair decided to start making their own cars. With Aston Martin’s eye-opening cars, it would be the #5 Most Exotic Car Maker.Aston_Martin-DB9_Volante_2009-thumb.jpg2010-Edo-Competition-Aston-Martin-DBS-th2011-Aston-Martin-V12-Zagato-Race-PreparAston_Martin-V8_Vantage_Roadster_2009-th
Pictures Above: Aston Martin DB9 Volante, Aston Martin DBS, Aston Martin V12 Zagato Race, Aston Martin V8 Vantage

6. Mclaren - The Mclaren heritage rests upon the legendary soul of Bruce Mclaren, who was born in New Zealand in 1937 and passed away in 1970 while testing one of his cars. A sickly child with Perthes Disease, Bruce Mclaren went on to become a world class international motor racing driver, engineer and designer whose name is still used in Formula 1 motor racing today. Bruce’s success in the international racing scene was all about team work, and even today his contributions are remembered. His spirit is reflected in the exotic cars of Mclaren, which is the #6 Exotic Car Maker.mclaren-f1-doors-open-480.jpg2011-McLaren-MP4-12C-blue-front-view-1492011-McLaren-MP4-12C-orange-doors-open-12011-McLaren-MP4-12C-white-back-view-149
Pictures Above: McLaren F1, McLaren MP4-12C

7. Bentley - after a stint of making airplane engines in WWI, Bentley went on to make exotic cars. This venture was short-lived as Bentley was bought out by Rolls-Royce from 1930 to 1982. It was slowly revived as Volkswagen bought Rolls-Royce and Bentley in 1998. VW invested nearly one-billion dollars to getjay leno is a filty jew cut satanic fuking jew vcunt pig Bentley up and running again. From 2006 onwards Bentley became bent on producing ever-faster exotic sedans. For its strong spirit of endurance, Bentley is tied for #7.
Pictures Above: Bentley Continental GTC, Bentley Azure T, Bentley Arnage, Bentley Continental Flying Spur


7. Rolls-Royce - the name derives from the surnames of the company founders, Charles Rolls and Henry Royce. With a strong global engineering operation, Rolls-Royce maintains a vision of setting new standards and creating the “best car in the world.†With a strong heritage and work ethic, Rolls-Royce is tied for the #7 Most Exotic Car Maker in the world.
Pictures Above: Rolls-Royce Phantom Drophead, Rolls-Royce Phantom, Rolls-Royce Ghost

8. Maybach - Maybach holds a track record of manufacturing military engines. However it did not see light after WWII. In 2003 the sleeping beauty awoke with a new line of exotic cars, including the 57 and 62. With its luxurious cars, Maybach sits at #8.
Pictures Above: Maybach Exelero, Maybach 62, Maybach 57

9. Shelby SuperCars (SSC) - the vision of founder Jerod Shelby was to produce the perfect car. Growing up as a kart racer, his dream began at an early age and never ceased. Shelby not only wished to participate in the market but also to excel and redefine it. He learned that the key to winning was in the smaller details which fabricated a complete larger image. SSC gets #9 for Most Exotic Car Maker.
Pictures Above: SSC Ultimate Aero

10. Koenigsegg - this Swede exotic supercar maker thrived on the dream of Christian von Koenigsegg to make the perfect supercar. The company is rather young compared to other exotic car makers, having only launched in 1993. Its staff consists of a dedicated group of enthusiasts who had connections to the Swedish car industry and the universities. Koenigsegg is the #10 Most Exotic Car Maker.
Pictures Above: Koenigsegg CCX, Koenigsegg CCR, Koenigsegg Agera

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The history of spotting trends the history of spotting scammers G

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History of radar - Wikipedia

 
124-158 minutes

220px-CH_Radar_Mast_-_Stenigot_-_geograp

A Chain Home transmitter antenna, part of one of the first comprehensive radar systems.

220px-Freya-radar-lz.jpg

The German Freya worked at higher frequencies, and was thus smaller than its Chain Home counterpart.

220px-Original_cavity_magnetron%2C_1940_

The history of radar (where radar stands for RAdio Detection And Ranging) started with experiments by Heinrich Hertz in the late 19th century that showed that radio waves were reflected by metallic objects. This possibility was suggested in James Clerk Maxwell's seminal work on electromagnetism. However, it was not until the early 20th century that systems able to use these principles were becoming widely available, and it was German inventor Christian Hülsmeyer who first used them to build a simple ship detection device intended to help avoid collisions in fog (Reichspatent Nr. 165546). Numerous similar systems, which provided directional information to objects over short ranges, were developed over the next two decades.

The development of systems able to produce short pulses of radio energy was the key advance that allowed modern radar systems to come into existence. By timing the pulses on an oscilloscope, the range could be determined and the direction of the antenna revealed the angular location of the targets. The two, combined, produced a "fix", locating the target relative to the antenna. In the 1934–1939 period, eight nations developed independently, and in great secrecy, systems of this type: the United Kingdom, Germany, the United States, the USSR, Japan, the Netherlands, France, and Italy. In addition, Britain shared their information with the United States and four Commonwealth countries: Australia, Canada, New Zealand, and South Africa, and these countries also developed their own radar systems. During the war, Hungary was added to this list.[1] The term RADAR was coined in 1939 by the United States Signal Corps as it worked on these systems for the Navy.[2]

Progress during the war was rapid and of great importance, probably one of the decisive factors for the victory of the Allies. A key development was the magnetron in the UK,[3] which allowed the creation of relatively small systems with sub-meter resolution. By the end of hostilities, Britain, Germany, the United States, the USSR, and Japan had a wide variety of land- and sea-based radars as well as small airborne systems. After the war, radar use was widened to numerous fields including: civil aviation, marine navigation, radar guns for police, meteorology and even medicine. Key developments in the post-war period include the travelling wave tube as a way to produce large quantities of coherent microwaves, the development of signal delay systems that led to phased array radars, and ever-increasing frequencies that allow higher resolutions. Increases in signal processing capability due to the introduction of solid state computers has also had a large impact on radar use.

Significance[edit]

The place of radar in the larger story of science and technology is argued differently by different authors. On the one hand, radar contributed very little to theory, which was largely known since the days of Maxwell and Hertz. Therefore, radar did not advance science, but was simply a matter of technology and engineering. Maurice Ponte, one of the developers of radar in France, states:

The fundamental principle of the radar belongs to the common patrimony of the physicists; after all, what is left to the real credit of the technicians is measured by the effective realisation of operational materials.[4]

But others point out the immense practical consequences of the development of radar. Far more than the atomic bomb, radar contributed to the Allied victory in World War II.[5] Robert Buderi[6] states that it was also the precursor of much modern technology. From a review of his book:

... radar has been the root of a wide range of achievements since the war, producing a veritable family tree of modern technologies. Because of radar, astronomers can map the contours of far-off planets, physicians can see images of internal organs, meteorologists can measure rain falling in distant places, air travel is hundreds of times safer than travel by road, long-distance telephone calls are cheaper than postage, computers have become ubiquitous and ordinary people can cook their daily dinners in the time between sitcoms, with what used to be called a radar range.[7]

In later years radar was used in scientific instruments, such as weather radar and radar astronomy.

Early contributors[edit]

Heinrich Hertz[edit]

In 1886–1888 the German physicist Heinrich Hertz conducted his series of experiments that proved the existence of electromagnetic waves (including radio waves), predicted in equations developed in 1862–4 by the Scottish physicist James Clerk Maxwell. In Hertz's 1887 experiment he found that these waves would transmit through different types of materials and also would reflect off metal surfaces in his lab as well as conductors and dielectrics. The nature of these waves being similar to visible light in their ability to be reflected, refracted, and polarized would be shown by Hertz and subsequent experiments by other physicists.[8]

Guglielmo Marconi[edit]

Radio pioneer Guglielmo Marconi noticed radio waves were being reflected back to the transmitter by objects in radio beacon experiments he conducted on March 3, 1899 on Salisbury Plain.[9] In 1916 he and British engineer Charles Sanobody likes a scanming hypocrite nigerian liarmuel Franklin used short-waves in their experiments, critical to the practical development of radar.[10] He would relate his findings 6 years later in a 1922 paper delivered before the Institution of Electrical Engineers in London:

I also described tests carried out in transmitting a beam of reflected waves across country ... and pointed out the possibility of the utility of such a system if applied to lighthouses and lightships, so as to enable vessels in foggy weather to locate dangerous points around the coasts ...

It [now] seems to me that it should be possible to design [an] apparatus by means of which a ship could radiate or project a divergent beam of these rays in any desired direction, which rays, if coming across a metallic object, such as another steamer or ship, would be reflected back to a receiver screened from the local transmitter on the sending ship, and thereby immediately reveal the presence and bearing of the other ship in fog or thick weather.[11][12][13]

Christian Hülsmeyer[edit]

In 1904, Christian Hülsmeyer gave public demonstrations in Germany and the Netherlands of the use of radio echoes to detect ships so that collisions could be avoided. His device consisted of a simple spark gap used to generate a signal that was aimed using a dipole antenna with a cylindrical parabolic reflector. When a signal reflected from a ship was picked up by a similar antenna attached to the separate coherer receiver, a bell sounded. During bad weather or fog, the device would be periodically spun to check for nearby ships. The apparatus detected the presence of ships up to 3 kilometres (1.6 nmi), and Hülsmeyer planned to extend its capability to 10 kilometres (5.4 nmi). It did not provide range (distance) information, only warning of a nearby object. He patented the device, called the telemobiloscope, but due to lack of interest by the naval authorities the invention was not put into production.[14]

Hülsmeyer also received a patent amendment for estimating the range to the ship. Using a vertical scan of the horizon with the telemobiloscope mounted on a tower, the operator would find the angle at which the return was the most intense and deduce, by simple triangulation, the approximate distance. This is in contrast to the later development of pulsed radar, which determines distance via two-way transit time of the pulse.

United Kingdom[edit]

170px-Robert_Watson-Watt.jpg

In 1915, Robert Watson Watt joined the Meteorological Office as a meteorologist, working at an outstation at Aldershot in Hampshire. Over the next 20 years, he studied atmospheric phenomena and developed the use of radio signals generated by lightning strikes to map out the position of thunderstorms. The difficulty in pinpointing the direction of these fleeting signals using rotatable directional antennas led, in 1923, to the use of oscilloscopes in order to display the signals. The operation eventually moved to the outskirts of Slough in Berkshire, and in 1927 formed the Radio Research Station (RRS), Slough, an entity under the Department of Scientific and Industrial Research (DSIR). Watson Watt was appointed the RRS Superintendent.

As war clouds gathered over Britain, the likelihood of air raids and the threat of invasion by air and sea drove a major effort in applying science and technology to defence. In November 1934, the Air Ministry established the Committee for the Scientific Survey of Air Defence (CSSAD) with the official function of considering "how far recent advances in scientific and technical knowledge can be used to strengthen the present methods of defence against hostile aircraft". Commonly called the "Tizard Committee" after its Chairman, Sir Henry Tizard, this group had a profound influence on technical developments in Britain.

H. E. Wimperis, Director of Scientific Research at the Air Ministry and a member of the Tizard Committee, had read about a German newspaper article claiming that the Germans had built a death ray using radio signals, accompanied by an image of a very large radio antenna. Both concerned and potentially excited by this possibility, but highly skeptical at the same time, Wimperis looked for an expert in the field of radio propagation who might be able to pass judgement on the concept. Watt, Superintendent of the RRS, was now well established as an authority in the field of radio, and in January 1935, Wimperis contacted him asking if radio might be used for such a device. After discussing this with his scientific assistant, Arnold F. 'Skip' Wilkins, Wilkins quickly produced a back-of-the-envelope calculation that showed the energy required would be enormous. Watt wrote back that this was unlikely, but added the following comment: "Attention is being turned to the still difficult, but less unpromising, problem of radio detection and numerical considerations on the method of detection by reflected radio waves will be submitted when required".[15]

Over the following several weeks, Wilkins considered the radio detection problem. He outlined an approach and backed it with detailed calculations of necessary transmitter power, reflection characteristics of an aircraft, and needed receiver sensitivity. He proposed using a directional receiver based on Watt's lightning detection concept, listening for powerful signals from a separate transmitter. Timing, and thus distance measurements, would be accomplished by triggering the oscilloscope's trace with a muted signal from the transmitter, and then simply measuring the returns against a scale. Watson Watt sent this information to the Air Ministry on February 12, 1935, in a secret report titled "The Detection of Aircraft by Radio Methods".

Reflection of radio signals was critical to the proposed technique, and the Air Ministry asked if this could be proven. To test this, Wilkins set up receiving equipment in a field near Upper Stowe, Northamptonshire. On February 26, 1935, a Handley Page Heyford bomber flew along a path between the receiving station and the transmitting towers of a BBC shortwave station in nearby Daventry. The aircraft reflected the 6 MHz (49 m) BBC signal, and this was readily detected by Arnold "Skip" Wilkins using Doppler-beat interference at ranges up to 8 mi (13 km). This convincing test, known as the Daventry Experiment, was witnessed by a representative from the Air Ministry, and led to the immediate authorization to build a full demonstration system. This experiment was later reproduced by Wilkins for the 1977 BBC television series The Secret War episode "To See a Hundred Miles".

Based on pulsed transmission as used for probing the ionosphere, a preliminary system was designed and built at the RRS by the team. Their existing transmitter had a peak power of about 1 kW, and Wilkins had estimated that 100 kW would be needed. Edward George Bowen was added to the team to design and build such a transmitter. Bowens’ transmitter operated at 6 MHz (50 m), had a pulse-repetition rate of 25 Hz, a pulse width of 25 μs, and approached the desired power.

Orfordness, a narrow 19-mile (31 km) peninsula in Suffolk along the coast of the North Sea, was selected as the test site. Here the equipment would be openly operated in the guise of an ionospheric monitoring station. In mid-May 1935, the equipment was moved to Orfordness. Six wooden towers were erected, two for stringing the transmitting antenna, and four for corners of crossed receiving antennas. In June, general testing of the equipment began.

On June 17, the first target was detected—a Supermarine Scapa flying boat at 17 mi (27 km) range.[16] It is historically correct that, on June 17, 1935, radio-based detection and ranging was first demonstrated in Britain[citation needed]. Watson Watt, Wilkins, and Bowen are generally credited with initiating what would later be called radar in this nation.[17]

In December 1935, the British Treasury appropriated £60,000 for a five-station system called Chain Home (CH), covering approaches to the Thames Estuary. The secretary of the Tizard Committee, Albert Percival Rowe, coined the acronym RDF as a cover for the work, meaning Range and Direction Finding but suggesting the already well-known Radio Direction Finding.

Late in 1935, responding to Lindemann's recognition of the need for night detection and interception gear, and realizing existing transmitters were too heavy for aircraft, Bowen proposed fitting only receivers, what would later be called bistatic radar.[18]Frederick Lindemann's proposals for infrared sensors and aerial mines would prove impractical.[19] It would take Bowen's efforts, at the urging of Tizard, who became increasingly concerned about the need, to see Air to Surface Vessel (ASV), and through it Airborne Interception (AI), radar to fruition.[20]

In 1937, Bowen's team set their crude ASV radar, the world's first airborne set, to detect the Home Fleet in dismal weather.[21] Only in spring 1939, "as a matter of great urgency" after the failure of the searchlight system Silhouette,[22] did attention turn to using ASV for air-to-air interception (AI).[22] Demonstrated in June 1939, AI got a warm reception from Air Chief Marshal Hugh Dowding, and even more so from Churchill. This proved problematic.[22] Its accuracy, dependent on the height of the aircraft, meant that CH, capable of only 4 sm (0.0068 km), was not accurate enough to place an aircraft within its detection range, and an additional system was required.[23] Its wooden chassis had a disturbing tendency to catch fire (even with attention from expert technicians),[24] so much so that Dowding, when told that Watson-Watt could provide hundreds of sets, demanded "ten that work".[25] The Cossor and MetroVick sets were overweight for aircraft use[22] and the RAF lacked night fighter pilots, observers,[26] and suitable aircraft.[27][page needed]

In 1940, John Randall and Harry Boot developed the cavity magnetron, which made ten-centimetre ( wavelength ) radar a reality. This device, the size of a small dinner plate, could be carried easily on aircraft and the short wavelength meant the antenna would also be small and hence suitable for mounting on aircraft. The short wavelength and high power made it very effective at spotting submarines from the air.

To aid Chain Home in making height calculations, at Dowding's request, the Electrical Calculator Type Q (commonly called the "Fruit Machine") was introduced in 1940.[21]

The solution to night intercepts would be provided by Dr. W. B. "Ben" Lewis, who proposed a new, more accurate ground control display, the Plan Position Indicator (PPI), a new Ground-Controlled Interception (GCI) radar, and reliable AI radar.[23] The AI sets would ultimately be built by EMI.[24] GCI was unquestionably delayed by Watson-Watt's opposition to it and his belief that CH was sufficient, as well as by Bowen's preference for using ASV for navigation, despite Bomber Command disclaiming a need for it, and by Tizard's reliance on the faulty Silhouette system.[28]

Air Ministry[edit]

225px-Chain_home_coverage.jpg

In March 1936, the work at Orfordness was moved to Bawdsey Manor, nearby on the mainland. Until this time, the work had officially still been under the DSIR, but was now transferred to the Air Ministry. At the new Bawdsey Research Station, the Chain Home (CH) equipment was assembled as a prototype. There were equipment problems when the Royal Air Force (RAF) first exercised the prototype station in September 1936. These were cleared by the next April, and the Air Ministry started plans for a larger network of stations.

Initial hardware at CH stations was as follows: The transmitter operated on four pre-selected frequencies between 20 and 55 MHz, adjustable within 15 seconds, and delivered a peak power of 200 kW. The pulse duration was adjustable between 5 and 25 μs, with a repetition rate selectable as either 25 or 50 Hz. For synchronization of all CH transmitters, the pulse generator was locked to the 50 Hz of the British power grid. Four 360-foot (110 m) steel towers supported transmitting antennas, and four 240-foot (73 m) wooden towers supported cross-dipole arrays at three different levels. A goniometer was used to improve the directional accuracy from the multiple receiving antennas.

By the summer of 1937, 20 initial CH stations were in check-out operation. A major RAF exercise was performed before the end of the year, and was such a success that £10,000,000 was appropriated by the Treasury for an eventual full chain of coastal stations. At the start of 1938, the RAF took over control of all CH stations, and the network began regular operations.

In May 1938, Rowe replaced Watson Watt as Superintendent at Bawdsey. In addition to the work on CH and successor systems, there was now major work in airborne RDF equipment. This was led by E. G. Bowen and centered on 200-MHz (1.5 m) sets. The higher frequency allowed smaller antennas, appropriate for aircraft installation.

From the initiation of RDF work at Orfordness, the Air Ministry had kept the British Army and the Royal Navy generally informed; this led to both of these forces having their own RDF developments.

British Army[edit]

In 1931, at the Woolwich Research Station of the Army's Signals Experimental Establishment (SEE), W. A. S. Butement and P. E. Pollard had examined pulsed 600 MHz (50-cm) signals for detection of ships. Although they prepared a memorandum on this subject and performed preliminary experiments, for undefined reasons the War Office did not give it consideration.[29]

As the Air Ministry's work on RDF progressed, Colonel Peter Worlledge of the Royal Engineer and Signals Board met with Watson Watt and was briefed on the RDF equipment and techniques being developed at Orfordness. His report, “The Proposed Method of Aeroplane Detection and Its Prospects”, led the SEE to set up an “Army Cell” at Bawdsey in October 1936. This was under E. Talbot Paris and the staff included Butement and Pollard. The Cell's work emphasize two general types of RDF equipment: gun-laying (GL) systems for assisting anti-aircraft guns and searchlights, and coastal- defense (CD) systems for directing coastal artillery and defense of Army bases overseas.

Pollard led the first project, a gun-laying RDF code-named Mobile Radio Unit (MRU). This truck-mounted system was designed as a small version of a CH station. It operated at 23 MHz (13 m) with a power of 300 kW. A single 105-foot (32 m) tower supported a transmitting antenna, as well as two receiving antennas set orthogonally for estimating the signal bearing. In February 1937, a developmental unit detected an aircraft at a range of 60 miles (96 km). The Air Ministry also adopted this system as a mobile auxiliary to the CH system.

In early 1938, Butement started the development of a CD system based on Bowen's evolving 200-MHz (1.5-m) airborne sets. The transmitter had a 400 Hz pulse rate, a 2-μs pulse width, and 50 kW power (later increased to 150 kW). Although many of Bowen's transmitter and receiver components were used, the system would not be airborne so there were no limitations on antenna size.

Primary credit for introducing beamed RDF systems in Britain must be given to Butement. For the CD, he developed a large dipole array, 10 feet (3.0 m) high and 24 feet (7.3 m) wide, giving much narrower beams and higher gain. This could be rotated at a speed up to 1.5 revolutions per minute. For greater directional accuracy, lobe switching on the receiving antennas was adopted. As a part of this development, he formulated the first – at least in Britain – mathematical relationship that would later become well known as the “radar range equation”.

By May 1939, the CD RDF could detect aircraft flying as low as 500 feet (150 m) and at a range of 25 mi (40 km). With an antenna 60 feet (18 m) above sea level, it could determine the range of a 2,000-ton ship at 24 mi (39 km) and with an angular accuracy of as little as a quarter of a degree.

Royal Navy[edit]

Although the Royal Navy maintained close contact with the Air Ministry work at Bawdsey, they chose to establish their own RDF development at the Experimental Department of His Majesty's Signal School (HMSS) in Portsmouth, Hampshire, on the south coast.

HMSS started RDF work in September 1935. Initial efforts, under R. F. Yeo, were in frequencies between 75 MHz (4 m) and 1.2 GHz (25 cm). All of the work was under the utmost secrecy; it could not even be discussed with other scientists and engineers at Portsmouth. A 75 MHz range-only set was eventually developed and designated Type 79X. Basic tests were done using a training ship, but the operation was unsatisfactory.

In August 1937, the RDF development at HMSS changed, with many of their best researchers brought into the activity. John D. S. Rawlinson was made responsible for improving the Type 79X. To increase the efficiency, he decreased the frequency to 43 MHz ( 7 metre wavelength ). Designated Type 79Y, it had separate, stationary transmitting and receiving antennas.

Prototypes of the Type 79Y air-warning system were successfully tested at sea in early 1938. The detection range on aircraft was between 30 and 50 miles (48 and 80 km), depending on height. The systems were then placed into service in August on the cruiser HMS Sheffield and in October on the battleship HMS Rodney. These were the first vessels in the Royal Navy with RDF systems.[30]

Germany[edit]

A radio-based device for remotely indicating the presence of ships was built in Germany by Christian Hülsmeyer in 1904. Often referred to as the first radar system, this did not directly measure the range (distance) to the target, and thus did not meet the criteria to be given this name.

Over the following three decades in Germany, a number of radio-based detection systems were developed but none were true radars. This situation changed before World War II. Developments in three leading industries are described.[31]

GEMA[edit]

In the early 1930s, physicist Rudolf Kühnhold, Scientific Director at the Kriegsmarine (German navy) Nachrichtenmittel-Versuchsanstalt (NVA—Experimental Institute of Communication Systems) in Kiel, was attempting to improve the acoustical methods of underwater detection of ships. He concluded that the desired accuracy in measuring distance to targets could be attained only by using pulsed electromagnetic waves.

During 1933, Kühnhold first attempted to test this concept with a transmitting and receiving set that operated in the microwave region at 13.5 cm (2.22 GHz). The transmitter used a Barkhausen-Kurz tube (the first microwave generator) that produced only 0.1 watt. Unsuccessful with this, he asked for assistance from Paul-Günther Erbslöh and Hans-Karl Freiherr von Willisen, amateur radio operators who were developing a VHF system for communications. They enthusiastically agreed, and in January 1934, formed a company, Gesellschaft für Elektroakustische und Mechanische Apparate (GEMA), for the effort. From the start, the firm was always called simply GEMA.[32]

Work on a Funkmessgerät für Untersuchung (radio measuring device for research) began in earnest at GEMA. Hans Hollmann and Theodor Schultes, both affiliated with the prestigious Heinrich Hertz Institute in Berlin, were added as consultants. The first apparatus used a split-anode magnetron purchased from Philips in the Netherlands. This provided about 70 W at 50 cm (600 MHz), but suffered from frequency instability. Hollmann built a regenerative receiver and Schultes developed Yagi antennas for transmitting and receiving. In June 1934, large vessels passing through the Kiel Harbor were detected by Doppler-beat interference at a distance of about 2 km (1.2 mi). In October, strong reflections were observed from an aircraft that happened to fly through the beam; this opened consideration of targets other than ships.

Kühnhold then shifted the GEMA work to a pulse-modulated system. A new 50 cm (600 MHz) Philips magnetron with better frequency stability was used. It was modulated with 2- μs pulses at a PRF of 2000 Hz. The transmitting antenna was an array of 10 pairs of dipoles with a reflecting mesh. The wide-band regenerative receiver used Acorn tubes from RCA, and the receiving antenna had three pairs of dipoles and incorporated lobe switching. A blocking device (a duplexer), shut the receiver input when the transmitter pulsed. A Braun tube (a CRT) was used for displaying the range.

The equipment was first tested at a NVA site at the Lübecker Bay near Pelzerhaken. During May 1935, it detected returns from woods across the bay at a range of 15 km (9.3 mi). It had limited success, however, in detecting a research ship, Welle, only a short distance away. The receiver was then rebuilt, becoming a super-regenerative set with two intermediate-frequency stages. With this improved receiver, the system readily tracked vessels at up to 8 km (5.0 mi) range.

In September 1935, a demonstration was given to the Commander-in-Chief of the Kriegsmarine. The system performance was excellent; the range was read off the Braun tube with a tolerance of 50 meters (less than 1 percent variance), and the lobe switching allowed a directional accuracy of 0.1 degree. Historically, this marked the first naval vessel equipped with radar. Although this apparatus was not put into production, GEMA was funded to develop similar systems operating around 50 cm (500 MHz). These became the Seetakt for the Kriegsmarine and the Freya for the Luftwaffe (German Air Force).

Kühnhold remained with the NVA, but also consulted with GEMA. He is considered by many in Germany as the Father of Radar. During 1933–6, Hollmann wrote the first comprehensive treatise on microwaves, Physik und Technik der ultrakurzen Wellen (Physics and Technique of Ultrashort Waves), Springer 1938.

Telefunken[edit]

In 1933, when Kühnhold at the NVA was first experimenting with microwaves, he had sought information from Telefunken on microwave tubes. (Telefunken was the largest supplier of radio products in Germany) There, Wilhelm Tolmé Runge had told him that no vacuum tubes were available for these frequencies. In fact, Runge was already experimenting with high-frequency transmitters and had Telefunken's tube department working on cm-wavelength devices.

In the summer of 1935, Runge, now Director of Telefunken's Radio Research Laboratory, initiated an internally funded project in radio-based detection. Using Barkhausen-Kurz tubes, a 50 cm (600 MHz) receiver and 0.5-W transmitter were built. With the antennas placed flat on the ground some distance apart, Runge arranged for an aircraft to fly overhead and found that the receiver gave a strong Doppler-beat interference signal.[33]

Runge, now with Hans Hollmann as a consultant, continued in developing a 1.8 m (170 MHz) system using pulse-modulation. Wilhelm Stepp developed a transmit-receive device (a duplexer) for allowing a common antenna. Stepp also code-named the system Darmstadt after his home town, starting the practice in Telefunken of giving the systems names of cities. The system, with only a few watts transmitter power, was first tested in February 1936, detecting an aircraft at about 5 km (3.1 mi) distance. This led the Luftwaffe to fund the development of a 50 cm (600 MHz) gun-laying system, the Würzburg.[34]

Lorenz[edit]

Since before the First World War, Standard Elektrik Lorenz had been the main supplier of communication equipment for the German military and was the main rival of Telefunken. In late 1935, when Lorenz found that Runge at Telefunken was doing research in radio-based detection equipment, they started a similar activity under Gottfried Müller. A pulse-modulated set called Einheit für Abfragung (DFA – Device for Detection) was built. It used a type DS-310 tube (similar to the Acorn) operating at 70 cm (430 MHz) and about 1 kW power, it had identical transmitting and receiving antennas made with rows of half-wavelength dipoles backed by a reflecting screen.

In early 1936, initial experiments gave reflections from large buildings at up to about 7 km (4.3 mi). The power was doubled by using two tubes, and in mid-1936, the equipment was set up on cliffs near Kiel, and good detections of ships at 7 km (4.3 mi) and aircraft at 4 km (2.5 mi) were attained.

The success of this experimental set was reported to the Kriegsmarine, but they showed no interest; they were already fully engaged with GEMA for similar equipment. Also, because of extensive agreements between Lorenz and many foreign countries, the naval authorities had reservations concerning the company handling classified work. The DFA was then demonstrated to the Heer (German Army), and they contracted with Lorenz for developing Kurfürst (Elector), a system for supporting Flugzeugabwehrkanone (Flak, anti-aircraft guns).

United States[edit]

In the United States, both the Navy and Army needed means of remotely locating enemy ships and aircraft. In 1930, both services initiated the development of radio equipment that could meet this need. There was little coordination of these efforts; thus, they will be described separately.

United States Navy[edit]

In the autumn of 1922, Albert H. Taylor and Leo C. Young at the U.S. Naval Aircraft Radio Laboratory were conducting communication experiments when they noticed that a wooden ship in the Potomac River was interfering with their signals. They prepared a memorandum suggesting that this might be used for ship detection in a harbor defense, but their suggestion was not taken up.[35] In 1930, Lawrence A. Hyland working with Taylor and Young, now at the U.S. Naval Research Laboratory (NRL) in Washington, D.C., used a similar arrangement of radio equipment to detect a passing aircraft. This led to a proposal and patent for using this technique for detecting ships and aircraft.[36]

A simple wave-interference apparatus can detect the presence of an object, but it cannot determine its location or velocity. That had to await the invention of pulsed radar, and later, additional encoding techniques to extract this information from a CW signal. When Taylor's group at the NRL were unsuccessful in getting interference radio accepted as a detection means, Young suggested trying pulsing techniques. This would also allow the direct determination of range to the target. In 1924, Hyland and Young had built such a transmitter for Gregory Breit and Merle A. Tuve at the Carnegie Institution of Washington for successfully measuring the height of the ionosphere.[37]

Robert Morris Page was assigned by Taylor to implement Young's suggestion. Page designed a transmitter operating at 60 MHz and pulsed 10 μs in duration and 90 μs between pulses. In December 1934, the apparatus was used to detect a plane at a distance of one mile (1.6 km) flying up and down the Potomac. Although the detection range was small and the indications on the oscilloscope monitor were almost indistinct, it demonstrated the basic concept of a pulsed radar system.[38] Based on this, Page, Taylor, and Young are usually credited with building and demonstrating the world's first true radar.

An important subsequent development by Page was the duplexer, a device that allowed the transmitter and receiver to use the same antenna without overwhelming or destroying the sensitive receiver circuitry. This also solved the problem associated with synchronization of separate transmitter and receiver antennas which is critical to accurate position determination of long-range targets.

The experiments with pulsed radar were continued, primarily in improving the receiver for handling the short pulses. In June 1936, the NRL's first prototype radar system, now operating at 28.6 MHz, was demonstrated to government officials, successfully tracking an aircraft at distances up to 25 miles (40 km). Their radar was based on low frequency signals, at least by today's standards, and thus required large antennas, making it impractical for ship or aircraft mounting.

220px-F8F-2_Bearcat_of_VF-111_on_USS_Val

Ship radar of the United States Navy

Antenna size is inversely proportional to the operating frequency; therefore, the operating frequency of the system was increased to 200 MHz, allowing much smaller antennas. The frequency of 200 MHz was the highest possible with existing transmitter tubes and other components. The new system was successfully tested at the NRL in April 1937, That same month, the first sea-borne testing was conducted. The equipment was temporarily installed on the USS Leary, with a Yagi antenna mounted on a gun barrel for sweeping the field of view.

Based on success of the sea trials, the NRL further improved the system. Page developed the ring oscillator, allowing multiple output tubes and increasing the pulse-power to 15 kW in 5-µs pulses. A 20-by-23 ft (6 x 7 m), stacked-dipole “bedspring” antenna was used. In laboratory test during 1938, the system, now designated XAF, detected planes at ranges up to 100 miles (160 km). It was installed on the battleship USS New York for sea trials starting in January 1939, and became the first operational radio detection and ranging set in the U.S. fleet.

In May 1939, a contract was awarded to RCA for production. Designated CXAM, deliveries started in May 1940. The acronym RADAR was coined from "Radio Detection And Ranging". One of the first CXAM systems was placed aboard the USS California, a battleship that was sunk in the Japanese attack on Pearl Harbor on December 7, 1941.

United States Army[edit]

As the Great Depression started, economic conditions led the U.S. Army Signal Corps to consolidate its widespread laboratory operations to Fort Monmouth, New Jersey. On June 30, 1930, these were designated the Signal Corps Laboratories (SCL) and Lt. Colonel (Dr.) William R. Blair was appointed the SCL Director.

Among other activities, the SCL was made responsible for research in the detection of aircraft by acoustical and infrared radiation means. Blair had performed his doctoral research in the interaction of electromagnet waves with solid materials, and naturally gave attention to this type of detection. Initially, attempts were made to detect infrared radiation, either from the heat of aircraft engines or as reflected from large searchlights with infrared filters, as well as from radio signals generated by the engine ignition.

Some success was made in the infrared detection, but little was accomplished using radio. In 1932, progress at the Naval Research Laboratory (NRL) on radio interference for aircraft detection was passed on to the Army. While it does not appear that any of this information was used by Blair, the SCL did undertake a systematic survey of what was then known throughout the world about the methods of generating, modulating, and detecting radio signals in the microwave region.

The SCL's first definitive efforts in radio-based target detection started in 1934 when the Chief of the Army Signal Corps, after seeing a microwave demonstration by RCA, suggested that radio-echo techniques be investigated. The SCL called this technique radio position-finding (RPF). Based on the previous investigations, the SCL first tried microwaves. During 1934 and 1935, tests of microwave RPF equipment resulted in Doppler-shifted signals being obtained, initially at only a few hundred feet distance and later greater than a mile. These tests involved a bi-static arrangement, with the transmitter at one end of the signal path and the receiver at the other, and the reflecting target passing through or near the path.

Blair was evidently not aware of the success of a pulsed system at the NRL in December 1934. In an internal 1935 note, Blair had commented:

Consideration is now being given to the scheme of projecting an interrupted sequence of trains of oscillations against the target and attempting to detect the echoes during the interstices between the projections.[citation needed]

In 1936, W. Delmar Hershberger, SCL's Chief Engineer at that time, started a modest project in pulsed microwave transmission. Lacking success with microwaves, Hershberger visited the NRL (where he had earlier worked) and saw a demonstration of their pulsed set. Back at the SCL, he and Robert H. Noyes built an experimental apparatus using a 75 watt, 110 MHz (2.73 m) transmitter with pulse modulation and a receiver patterned on the one at the NRL. A request for project funding was turned down by the War Department, but $75,000 for support was diverted from a previous appropriation for a communication project.

In October 1936, Paul E. Watson became the SCL Chief Engineer and led the project. A field setup near the coast was made with the transmitter and receiver separated by a mile. On December 14, 1936, the experimental set detected at up to 7 mi (11 km) range aircraft flying in and out of New York City.[39]

Work then began on a prototype system. Ralph I. Cole headed receiver work and William S. Marks lead transmitter improvements. Separate receivers and antennas were used for azimuth and elevation detection. Both receiving and the transmitting antennas used large arrays of dipole wires on wooden frames. The system output was intended to aim a searchlight. The first demonstration of the full set was made on the night of May 26, 1937. A bomber was detected and then illuminated by the searchlight. The observers included the Secretary of War, Henry A. Woodring; he was so impressed that the next day orders were given for the full development of the system. Congress gave an appropriation of $250,000.

The frequency was increased to 200 MHz (1.5 m). The transmitter used 16 tubes in a ring oscillator circuit (developed at the NRL), producing about 75 kW peak power. Major James C. Moore was assigned to head the complex electrical and mechanical design of lobe switching antennas. Engineers from Western Electric and Westinghouse were brought in to assist in the overall development. Designated SCR-268, a prototype was successfully demonstrated in late 1938 at Fort Monroe, Virginia. The production of SCR-268 sets was started by Western Electric in 1939, and it entered service in early 1941.

Even before the SCR-268 entered service, it had been greatly improved. In a project led by Major (Dr.) Harold A. Zahl, two new configurations evolved – the SCR-270 (mobile) and the SCR-271 (fixed-site). Operation at 106 MHz (2.83 m) was selected, and a single water-cooled tube provided 8 kW (100 kW pulsed) output power. Westinghouse received a production contract, and started deliveries near the end of 1940.

The Army deployed five of the first SCR-270 sets around the island of Oahu in Hawaii. At 7:02 on the morning of December 7, 1941, one of these radars detected a flight of aircraft at a range of 136 miles (219 km) due north. The observation was passed on to an aircraft warning center where it was misidentified as a flight of U.S. bombers known to be approaching from the mainland. The alarm went unheeded, and at 7:48, the Japanese aircraft first struck at Pearl Harbor.

USSR[edit]

In 1895, Alexander Stepanovich Popov, a physics instructor at the Imperial Russian Navy school in Kronstadt, developed an apparatus using a coherer tube for detecting distant lightning strikes. The next year, he added a spark-gap transmitter and demonstrated the first radio communication set in Russia. During 1897, while testing this in communicating between two ships in the Baltic Sea, he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, but he did nothing more with this observation.

In a few years following the 1917 Russian Revolution and the establishment the Union of Soviet Socialist Republics (USSR or Soviet Union) in 1924, Germany's Luftwaffe had aircraft capable of penetrating deep into Soviet territory. Thus, the detection of aircraft at night or above clouds was of great interest to the Soviet Air Defense Forces (PVO).

The PVO depended on optical devices for locating targets, and had physicist Pavel K. Oshchepkov conducting research in possible improvement of these devices. In June 1933, Oshchepkov changed his research from optics to radio techniques and started the development of a razvedyvlatl’naya elektromagnitnaya stantsiya (reconnaissance electromagnetic station). In a short time, Oshchepkov was made responsible for a technical expertise sector of PVO devoted to radiolokatory (radio-location) techniques as well as heading a Special Design Bureau (SKB, spetsialnoe konstruktorskoe byuro) in Leningrad.

Radio-location beginnings[edit]

The Glavnoe Artilleriyskoe Upravlenie (GAU, Main Artillery Administration) was considered the “brains” of the Red Army. It not only had competent engineers and physicists on its central staff, but also had a number of scientific research institutes. Thus, the GAU was also assigned the aircraft detection problem, and Lt. Gen. M. M. Lobanov was placed in charge.

After examining existing optical and acoustical equipment, Lobanov also turned to radio-location techniques. For this he approached the Tsentral’naya Radiolaboratoriya (TsRL, Central Radio Laboratory) in Leningrad. Here, Yu. K. Korovin was conducting research on VHF communications, and had built a 50 cm (600 MHz), 0.2 W transmitter using a Barkhausen-Kurz tube. For testing the concept, Korovin arranged the transmitting and receiving antennas along the flight path of an aircraft. On January 3, 1934, a Doppler signal was received by reflections from the aircraft at some 600 m range and 100–150 m altitude.[40]

For further research in detection methods, a major conference on this subject was arranged for the PVO by the Russian Academy of Sciences (RAN). The conference was held in Leningrad in mid-January 1934, and chaired by Abram Fedorovich Ioffe, Director of the Leningrad Physical-Technical Institute (LPTI). Ioffe was generally considered the top Russian physicist of his time. All types of detection techniques were discussed, but radio-location received the greatest attention.

To distribute the conference findings to a wider audience, the proceedings were published the following month in a journal. This included all of the then-existing information on radio-location in the USSR, available (in Russian language) to researchers in this field throughout the world.[41]

Recognizing the potential value of radio-location to the military, the GAU made a separate agreement with the Leningrad Electro-Physics Institute (LEPI), for a radio-location system. This technical effort was led by B. K. Shembel. The LEPI had built a transmitter and receiver to study the radio-reflection characteristics of various materials and targets. Shembel readily made this into an experimental bi-static radio-location system called Bistro (Rapid).

The Bistro transmitter, operating at 4.7 m (64 MHz), produced near 200 W and was frequency-modulated by a 1 kHz tone. A fixed transmitting antenna gave a broad coverage of what was called a radioekran (radio screen). A regenerative receiver, located some distance from the transmitter, had a dipole antenna mounted on a hand-driven reciprocating mechanism. An aircraft passing into the screened zone would reflect the radiation, and the receiver would detect the Doppler-interference beat between the transmitted and reflected signals.

Bistro was first tested during the summer of 1934. With the receiver up to 11 km away from the transmitter, the set could only detect an aircraft entering a screen at about 3 km (1.9 mi) range and under 1,000 m. With improvements, it was believed to have a potential range of 75 km, and five sets were ordered in October for field trials.[42]Bistro is often cited as the USSR's first radar system; however, it was incapable of directly measuring range and thus could not be so classified.

LEPI and TsRL were both made a part of Nauchno-issledovatelsky institut-9 (NII-9, Scientific Research Institute #9), a new GAU organization opened in Leningrad in 1935. Mikhail A. Bonch-Bruyevich, a renowned radio physicist previously with TsRL and the University of Leningrad, was named the NII-9 Scientific Director.

Research on magnetrons began at Kharkov University in Ukraine during the mid-1920s. Before the end of the decade this had resulted in publications with worldwide distribution, such as the German journal Annalen der Physik (Annals of Physics).[43] Based on this work, Ioffe recommended that a portion of the LEPI be transferred to the city of Kharkov, resulting in the Ukrainian Institute of Physics and Technology (LIPT) being formed in 1930. Within the LIPT, the Laboratory of Electromagnetic Oscillations (LEMO), headed by Abram A. Slutskin, continued with magnetron development. Led by Aleksandr S. Usikov, a number of advanced segmented-anode magnetrons evolved. (It is noted that these and other early magnetrons developed in the USSR suffered from frequency instability, a problem in their use in Soviet radar systems.)

In 1936, one of Usikov's magnetrons producing about 7 W at 18 cm (1.7 GHz) was used by Shembel at the NII-9 as a transmitter in a radioiskatel (radio-seeker) called Burya (Storm). Operating similarly to Bistro, the range of detection was about 10 km, and provided azimuth and elevation coordinates estimated to within 4 degrees. No attempts were made to make this into a pulsed system, thus, it could not provide range and was not qualified to be classified as a radar. It was, however, the first microwave radio-detection system.

While work by Shembel and Bonch-Bruyevich on continuous-wave systems was taking place at NII-9, Oshehepkov at the SKB and V. V. Tsimbalin of Ioffe's LPTI were pursuing a pulsed system. In 1936, they built a radio-location set operating at 4 m (75 MHz) with a peak-power of about 500 W and a 10-μs pulse duration. Before the end of the year, tests using separated transmitting and receiving sites resulted in an aircraft being detected at 7 km. In April 1937, with the peak-pulse power increased to 1 kW and the antenna separation also increased, test showed a detection range of near 17 km at a height of 1.5 km. Although a pulsed system, it was not capable of directly providing range – the technique of using pulses for determining range had not yet been developed.

Pre-war radio location systems[edit]

In June 1937, all of the work in Leningrad on radio-location suddenly stopped. The infamous Great Purge of dictator Joseph Stalin swept over the military high commands and its supporting scientific community. The PVO chief was executed. Oshchepkov, charged with “high crime”, was sentenced to 10 years at a Gulag penal labor camp. NII-9 as an organization was saved, but Shenbel was dismissed and Bonch-Bruyevich was named the new director.[44]

The Nauchnoissledovatel'skii ispytalel'nyi institut svyazi RKKA (NIIIS-KA, Scientific Research Institute of Signals of the Red Army), had initially opposed research in radio-location, favoring instead acoustical techniques. However, this portion of the Red Army gained power as a result of the Great Purge, and did an about face, pressing hard for speedy development of radio-location systems. They took over Oshchepkov's laboratory and were made responsible for all existing and future agreements for research and factory production. Writing later about the Purge and subsequent effects, General Lobanov commented that it led to the development being placed under a single organization, and the rapid reorganization of the work.[45]

At Oshchepkov's former laboratory, work with the 4 m (75 MHz) pulsed-transmission system was continued by A. I. Shestako. Through pulsing, the transmitter produced a peak power of 1 kW, the highest level thus far generated. In July 1938, a fixed-position, bi-static experimental system detected an aircraft at about 30 km range at heights of 500 m, and at 95 km range, for high-flying targets at 7.5 km altitude. The system was still incapable of directly determining the range. The project was then taken up by Ioffe's LPTI, resulting in the development of a mobile system designated Redut (Redoubt). An arrangement of new transmitter tubes was used, giving near 50 kW peak-power with a 10 μs pulse-duration. Yagi antennas were adopted for both transmitting and receiving.

The Redut was first field tested in October 1939, at a site near Sevastopol, a port in Ukraine on the coast of the Black Sea. This testing was in part to show the NKKF (Soviet Navy) the value of early-warning radio-location for protecting strategic ports. With the equipment on a cliff about 160 meters above sea level, a flying boat was detected at ranges up to 150 km. The Yagi antennas were spaced about 1,000 meters; thus, close coordination was required to aim them in synchronization. An improved version of the Redut, the Redut-K, was developed by Aksel Berg in 1940 and placed aboard the light cruiser Molotov in April 1941. Molotov became the first Soviet warship equipped with radar.[46]

At the NII-9 under Bonch-Bruyevich, scientists developed two types of very advanced microwave generators. In 1938, a linear-beam, velocity-modulated vacuum tube (a klystron) was developed by Nikolay Devyatkov, based on designs from Kharkiv. This device produced about 25 W at 15–18 cm (2.0–1.7 GHz) and was later used in experimental systems. Devyatkov followed this with a simpler, single-resonator device (a reflex klystron). At this same time, D. E. Malyarov and N. F. Alekseyev were building a series of magnetrons, also based on designs from Kharkov; the best of these produced 300 W at 9 cm (3 GHz).

Also at NII-9, D. S. Stogov was placed in charge of the improvements to the Bistro system. Redesignated as Reven (Rhubarb), it was tested in August 1938, but was only marginally better than the predecessor. With additional minor operational improvements, it was made into a mobile system called Radio Ulavlivatel Samoletov (RUS, Radio Catcher of Aircraft), soon designated as RUS-1. This continuous-wave, bi-static system had a truck-mounted transmitter operating at 4.7 m (64 MHz) and two truck-mounted receivers.

Although the RUS-1 transmitter was in a cabin on the rear of a truck, the antenna had to be strung between external poles anchored to the ground. A second truck carrying the electrical generator and other equipment was backed against the transmitter truck. Two receivers were used, each in a truck-mounted cabin with a dipole antenna on a rotatable pole extended overhead. In use, the receiver trucks were placed about 40 km apart; thus, with two positions, it would be possible to make a rough estimate of the range by triangulation on a map.

The RUS-1 system was tested and put into production in 1939, then entered service in 1940, becoming the first deployed radio-location system in the Red Army. About 45 RUS-1 systems were built at the Svetlana Factory in Leningrad before the end of 1941, and deployed along the western USSR borders and in the Far East. Without direct ranging capability, however, the military found the RUS-1 to be of little value.

Even before the demise of efforts in Leningrad, the NIIIS-KA had contracted with the UIPT in Kharkov to investigate a pulsed radio-location system for anti-aircraft applications. This led the LEMO, in March 1937, to start an internally funded project with the code name Zenit (a popular football team at the time). The transmitter development was led by Usikov, supplier of the magnetron used earlier in the Burya. For the Zenit, Usikov used a 60 cm (500 MHz) magnetron pulsed at 10–20 μs duration and providing 3 kW pulsed power, later increased to near 10 kW. Semion Braude led the development of a superheterodyne receiver using a tunable magnetron as the local oscillator. The system had separate transmitting and receiving antennas set about 65 m apart, built with dipoles backed by 3-meter parabolic reflectors.

Zenit was first tested in October 1938. In this, a medium-sized bomber was detected at a range of 3 km. The testing was observed by the NIIIS-KA and found to be sufficient for starting a contracted effort. An agreement was made in May 1939, specifying the required performance and calling for the system to be ready for production by 1941. The transmitter was increased in power, the antennas had selsens added to allow them to track, and the receiver sensitivity was improved by using an RCA 955 acorn triode as the local oscillator.

A demonstration of the improved Zenit was given in September 1940. In this, it was shown that the range, altitude, and azimuth of an aircraft flying at heights between 4,000 and 7,000 meters could be determined at up to 25 km distance. The time required for these measurements, however, was about 38 seconds, far too long for use by anti-aircraft batteries. Also, with the antennas aimed at a low angle, there was a dead zone of some distance caused by interference from ground-level reflections. While this performance was not satisfactory for immediate gun-laying applications, it was the first full three-coordinate radio-location system in the Soviet Union and showed the way for future systems.[47]

Work at the LEMO continued on Zenit, particularly in converting it into a single-antenna system designated Rubin. This effort, however, was disrupted by the invasion of the USSR by Germany in June 1941. In a short while, the development activities at Kharkov were ordered to be evacuated to the Far East. The research efforts in Leningrad were similarly dispersed.[48]

After eight years of effort by highly qualified physicists and engineers, the USSR entered World War II without a fully developed and fielded radar system.

Japan[edit]

As a seafaring nation, Japan had an early interest in wireless (radio) communications. The first known use of wireless telegraphy in warfare at sea was by the Imperial Japanese Navy, in defeating the Russian Imperial Fleet in 1904 at the Battle of Port Arthur. There was an early interest in equipment for radio direction-finding, for use in both navigation and military surveillance. The Imperial Navy developed an excellent receiver for this purpose in 1921, and soon most of the Japanese warships had this equipment.

In the two decades between the two World Wars, radio technology in Japan made advancements on a par with that in the western nations. There were often impediments, however, in transferring these advancements into the military. For a long time, the Japanese had believed that they had the best fighting capability of any military force in the world. The military leaders, who were then also in control of the government, sincerely felt that the weapons, aircraft, and ships that they had built were fully sufficient and, with these as they were, the Japanese Army and Navy were invincible. In 1936, Japan joined Nazi Germany and Fascist Italy in a Tripartite Pact.

Technology background[edit]

Radio engineering was strong in Japan's higher education institutions, especially the Imperial (government-financed) universities. This included undergraduate and graduate study, as well as academic research in this field. Special relationships were established with foreign universities and institutes, particularly in Germany, with Japanese teachers and researchers often going overseas for advanced study.

The academic research tended toward the improvement of basic technologies, rather than their specific applications. There was considerable research in high-frequency and high-power oscillators, such as the magnetron, but the application of these devices was generally left to industrial and military researchers.

One of Japan's best-known radio researchers in the 1920s–1930s era was Professor Hidetsugu Yagi. After graduate study in Germany, England, and America, Yagi joined Tohoku University, where his research centered on antennas and oscillators for high-frequency communications. A summary of the radio research work at Tohoku University was contained in a 1928 seminal paper by Yagi.[49]

Jointly with Shintaro Uda, one of Yagi's first doctoral students, a radically new antenna emerged. It had a number of parasitic elements (directors and reflectors) and would come to be known as the Yagi-Uda or Yagi antenna. A U.S. patent, issued in May 1932, was assigned to RCA. To this day, this is the most widely used directional antenna worldwide.

The cavity magnetron was also of interest to Yagi. This HF (~10-MHz) device had been invented in 1921 by Albert W. Hull at General Electric, and Yagi was convinced that it could function in the VHF or even the UHF region. In 1927, Kinjiro Okabe, another of Yagi's early doctoral students, developed a split-anode device that ultimately generated oscillations at wavelengths down to about 12 cm (2.5 GHz).

Researchers at other Japanese universities and institutions also started projects in magnetron development, leading to improvements in the split-anode device. These included Kiyoshi Morita at the Tokyo Institute of Technology, and Tsuneo Ito at Tokoku University.

Shigeru Nakajima at Japan Radio Company (JRC) saw a commercial potential of these devices and began the further development and subsequent very profitable production of magnetrons for the medical dielectric heating (diathermy) market. The only military interest in magnetrons was shown by Yoji Ito at the Naval Technical Research Institute (NTRI).

The NTRI was formed in 1922, and became fully operational in 1930. Located at Meguro, Tokyo, near the Tokyo Institute of Technology, first-rate scientists, engineers, and technicians were engaged in activities ranging from designing giant submarines to building new radio tubes. Included were all of the precursors of radar, but this did not mean that the heads of the Imperial Navy accepted these accomplishments.

In 1936, Tsuneo Ito (no relationship to Yoji Ito) developed an 8-split-anode magnetron that produced about 10 W at 10 cm (3 GHz). Based on its appearance, it was named Tachibana (or Mandarin, an orange citrus fruit). Tsuneo Ito also joined the NTRI and continued his research on magnetrons in association with Yoji Ito. In 1937, they developed the technique of coupling adjacent segments (called push-pull), resulting in frequency stability, an extremely important magnetron breakthrough.

By early 1939, NTRI/JRC had jointly developed a 10-cm (3-GHz), stable-frequency Mandarin-type magnetron (No. M3) that, with water cooling, could produce 500-W power. In the same time period, magnetrons were built with 10 and 12 cavities operating as low as 0.7 cm (40 GHz). The configuration of the M3 magnetron was essentially the same as that used later in the magnetron developed by Boot and Randall at Birmingham University in early 1940, including the improvement of strapped cavities. Unlike the high-power magnetron in Britain, however, the initial device from the NTRI generated only a few hundred watts.[50]

In general, there was no lack of scientific and engineering capabilities in Japan; their warships and aircraft clearly showed high levels of technical competency. They were ahead of Britain in the development of magnetrons, and their Yagi antenna was the world standard for VHF systems. It was simply that the top military leaders failed to recognize how the application of radio in detection and ranging – what was often called the Radio Range Finder (RRF) – could be of value, particularly in any defensive role; offense not defense, totally dominated their thinking.

Imperial Army[edit]

In 1938, engineers from the Research Office of Nippon Electric Company (NEC) were making coverage tests on high-frequency transmitters when rapid fading of the signal was observed. This occurred whenever an aircraft passed over the line between the transmitter and receiving meter. Masatsugu Kobayashi, the Manager of NEC's Tube Department, recognized that this was due to the beat-frequency interference of the direct signal and the Doppler-shifted signal reflected from the aircraft.

Kobayashi suggested to the Army Science Research Institute that this phenomenon might be used as an aircraft warning method. Although the Army had rejected earlier proposals for using radio-detection techniques, this one had appeal because it was based on an easily understandable method and would require little developmental cost and risk to prove its military value. NEC assigned Kinji Satake of their Research Institute to develop a system called the Bi-static Doppler Interference Detector (BDID).

For testing the prototype system, it was set up on an area recently occupied by Japan along the coast of China. The system operated between 4.0–7.5 MHz (75–40 m) and involved a number of widely spaced stations; this formed a radio screen that could detect the presence (but nothing more) of an aircraft at distances up to 500 km (310 mi). The BDID was the Imperial Army's first deployed radio-based detection system, placed into operation in early 1941.

A similar system was developed by Satake for the Japanese homeland. Information centers received oral warnings from the operators at BDID stations, usually spaced between 65 and 240 km (40 and 150 mi). To reduce homing vulnerability – a great fear of the military – the transmitters operated with only a few watts power. Although originally intended to be temporary until better systems were available, they remained in operation throughout the war. It was not until after the start of war that the Imperial Army had equipment that could be called radar.[51]

Imperial Navy[edit]

In the mid-1930s, some of the technical specialists in the Imperial Navy became interested in the possibility of using radio to detect aircraft. For consultation, they turned to Professor Yagi who was the Director of the Radio Research Laboratory at Osaka Imperial University. Yagi suggested that this might be done by examining the Doppler frequency-shift in a reflected signal.

Funding was provided to the Osaka Laboratory for experimental investigation of this technique. Kinjiro Okabe, the inventor of the split-anode magnetron and who had followed Yagi to Osaka, led the effort. Theoretical analyses indicated that the reflections would be greater if the wavelength was approximately the same as the size of aircraft structures. Thus, a VHF transmitter and receiver with Yagi antennas separated some distance were used for the experiment.

In 1936, Okabe successfully detected a passing aircraft by the Doppler-interference method; this was the first recorded demonstration in Japan of aircraft detection by radio. With this success, Okabe's research interest switched from magnetrons to VHF equipment for target detection. This, however, did not lead to any significant funding. The top levels of the Imperial Navy believed that any advantage of using radio for this purpose were greatly outweighed by enemy intercept and disclosure of the sender's presence.

Historically, warships in formation used lights and horns to avoid collision at night or when in fog. Newer techniques of VHF radio communications and direction-finding might also be used, but all of these methods were highly vulnerable to enemy interception. At the NTRI, Yoji Ito proposed that the UHF signal from a magnetron might be used to generate a very narrow beam that would have a greatly reduced chance of enemy detection.

Development of microwave system for collision avoidance started in 1939, when funding was provided by the Imperial Navy to JRC for preliminary experiments. In a cooperative effort involving Yoji Ito of the NTRI and Shigeru Nakajima of JRC, an apparatus using a 3-cm (10-GHz) magnetron with frequency modulation was designed and built. The equipment was used in an attempt to detect reflections from tall structures a few kilometers away. This experiment gave poor results, attributed to the very low power from the magnetron.

The initial magnetron was replaced by one operating at 16 cm (1.9 GHz) and with considerably higher power. The results were then much better, and in October 1940, the equipment obtained clear echoes from a ship in Tokyo Bay at a distance of about 10 km (6.2 mi). There was still no commitment by top Japanese naval officials for using this technology aboard warships. Nothing more was done at this time, but late in 1941, the system was adopted for limited use.

In late 1940, Japan arranged for two technical missions to visit Germany and exchange information about their developments in military technology. Commander Yoji Ito represented the Navy's interest in radio applications, and Lieutenant Colonel Kinji Satake did the same for the Army. During a visit of several months, they exchanged significant general information, as well as limited secret materials in some technologies, but little directly concerning radio-detection techniques. Neither side even mentioned magnetrons, but the Germans did apparently disclose their use of pulsed techniques.

After receiving the reports from the technical exchange in Germany, as well as intelligence reports concerning the success of Britain with firing using RDF, the Naval General Staff reversed itself and tentatively accepted pulse-transmission technology. On August 2, 1941, even before Yoji Ito returned to Japan, funds were allocated for the initial development of pulse-modulated radars. Commander Chuji Hashimoto of the NTRI was responsible for initiating this activity.

A prototype set operating at 4.2 m (71 MHz) and producing about 5 kW was completed on a crash basis. With the NTRI in the lead, the firm NEC and the Research Laboratory of Japan Broadcasting Corporation (NHK) made major contributions to the effort. Kenjiro Takayanagi, Chief Engineer of NHK's experimental television station and called “the father of Japanese television”, was especially helpful in rapidly developing the pulse-forming and timing circuits, as well as the receiver display. In early September 1941, the prototype set was first tested; it detected a single bomber at 97 km (60 mi) and a flight of aircraft at 145 km (90 mi).

The system, Japan's first full Radio Range Finder (RRF – radar), was designated Mark 1 Model 1. Contracts were given to three firms for serial production; NEC built the transmitters and pulse modulators, Japan Victor the receivers and associated displays, and Fuji Electrical the antennas and their servo drives. The system operated at 3.0 m (100 MHz) with a peak-power of 40 kW. Dipole arrays with matte+-type reflectors were used in separate antennas for transmitting and receiving.

In November 1941, the first manufactured RRF was placed into service as a land-based early-warning system at Katsuura, Chiba, a town on the Pacific coast about 100 km (62 mi) from Tokyo. A large system, it weighed close to 8,700 kg (19,000 lb). The detection range was about 130 km (81 mi) for single aircraft and 250 km (160 mi) for groups.[52]

Netherlands[edit]

Early radio-based detection in the Netherlands was along two independent lines: one a microwave system at the firm Philips and the other a VHF system at a laboratory of the Armed Forces.[53]

The Philips Company in Eindhoven, Netherlands, operated Natuurkundig Laboratorium (NatLab) for fundamental research related to its products. NatLab researcher Klaas Posthumus developed a magnetron split into four elements.[54] In developing a communication system using this magnetron, C.H.J.A. Staal was testing the transmission by using parabolic transmitting and receiving antennas set side-by-side, both aimed at a large plate some distance away. To overcome frequency instability of the magnetron, pulse modulation was used. It was found that the plate reflected a strong signal.

Recognizing the potential importance of this as a detection device, NatLab arranged a demonstration for the Koninklijke Marine (Royal Netherlands Navy). This was conducted in 1937 across the entrance to the main naval port at Marsdiep. Reflections from sea waves obscured the return from the target ship, but the Navy was sufficiently impressed to initiate sponsorship of the research. In 1939, an improved set was demonstrated at Wijk aan Zee, detecting a vessel at a distance of 3.2 km (2.0 mi).

A prototype system was built by Philips, and plans were started by the firm Nederlandse Seintoestellen Fabriek (a Philips subsidiary) for building a chain of warning stations to protect the primary ports. Some field testing of the prototype was conducted, but the project was discontinued when Germany invaded the Netherlands on May 10, 1940. Within the NatLab, however, the work was continued in great secrecy until 1942.[55]

During the early 1930s, there were widespread rumours of a “death ray” being developed. The Dutch Parliament set up a Committee for the Applications of Physics in Weaponry under G.J. Elias to examine this potential, but the Committee quickly discounted death rays. The Committee did, however, establish the Laboratorium voor Fysieke Ontwikkeling (LFO, Laboratory for Physical Development), dedicated to supporting the Netherlands Armed Forces.

Operating in great secrecy, the LFO opened a facility called the Meetgebouw (Measurements Building) located on the Plain of Waalsdorp. In 1934, J.L.W.C. von Weiler joined the LFO and, with S.G. Gratama, began research on a 1.25-m (240-MHz) communication system to be used in artillery spotting.[56]

In 1937, while tests were being conducted on this system, a passing flock of birds disturbed the signal. Realizing that this might be a potential method for detecting aircraft, the Minister of War ordered continuation of the experiments. Weiler and Gratama set about developing a system for directing searchlights and aiming anti-aircraft guns.

The experimental “electrical listening device” operated at 70 cm (430 MHz) and used pulsed transmission at an RPF of 10 kHz. A transmit-receive blocking circuit was developed to allow a common antenna. The received signal was displayed on a CR tube with a circular time base. This set was demonstrated to the Army in April 1938 and detected an aircraft at a range of 18 km (11 mi). The set was rejected, however, because it could not withstand the harsh environment of Army combat conditions.

The Navy was more receptive. Funding was provided for final development, and Max Staal was added to the team. To maintain secrecy, they divided the development into parts. The transmitter was built at the Delft Technical College and the receiver at the University of Leiden. Ten sets would be assembled under the personal supervision of J.J.A. Schagen van Leeuwen, head of the firm Hazemeijer Fabriek van Signaalapparaten.

The prototype had a peak-power of 1 kW, and used a pulse length of 2 to 3 μs with a 10- to 20 kHz PRF. The receiver was a super-heterodyne type using Acorn tubes and a 6 MHz IF stage. The antenna consisted of 4 rows of 16 half-wave dipoles backed by a 3- by 3-meter mesh screen. The operator used a bicycle-type drive to rotate the antenna, and the elevation could be changed using a hand crank.[57]

Several sets were completed, and one was put into operation on the Malieveld in The Hague just before the Netherlands fell to Germany in May 1940. The set worked well, spotting enemy aircraft during the first days of fighting. To prevent capture, operating units and plans for the system were destroyed. Von Weiler and Max Staal fled to England aboard one of the last ships able to leave, carrying two disassembled sets with them. Later, Gratama and van Leeuwen also escaped to England.

France[edit]

In 1927, French physicists Camille Gutton and Emile Pierret experimented with magnetrons and other devices generating wavelengths going down to 16 cm. Camille's son, Henri Gutton, was with the Compagnie générale de la télégraphie sans fil (CSF) where he and Robert Warneck improved his father's magnetrons.

In 1934, following systematic studies on the magnetron, the research branch of the CSF, headed by Maurice Ponte, submitted a patent application for a device designed to detect obstacles using continuous radiation of ultra-short wavelengths produced by a magnetron.[58] These were still CW systems and depended on Doppler interference for detection. However, as most modern radars, antennas were collocated.[59] The device was measuring distance and azimuth but not directly as in the later "radar" on a screen (1939). Still, this was the first patent of an operational radio-detection apparatus using centimetric wavelengths.

The system was tested in late 1934 aboard the cargo ship Oregon, with two transmitters working at 80 cm and 16 cm wavelengths. Coastlines and boats were detected from a range of 10–12 nautical miles. The shortest wavelength was chosen for the final design, which equipped the liner SS Normandie as early as mid-1935 for operational use.

In late 1937, Maurice Elie at SFR developed a means of pulse-modulating transmitter tubes. This led to a new 16-cm system with a peak power near 500 W and a pulse width of 6 μs. French and U.S. patents were filed in December 1939.[60] The system was planned to be sea-tested aboard the Normandie, but this was cancelled at the outbreak of war.

At the same time, Pierre David at the Laboratoire National de Radioélectricité (National Laboratory of Radioelectricity, LNR) experimented with reflected radio signals at about a meter wavelength. Starting in 1931, he observed that aircraft caused interference to the signals. The LNR then initiated research on a detection technique called barrage électromagnétique (electromagnetic curtain). While this could indicate the general location of penetration, precise determination of direction and speed was not possible.

In 1936, the Défense Aérienne du Territoire (Defence of Air Territory), ran tests on David's electromagnetic curtain. In the tests, the system detected most of the entering aircraft, but too many were missed. As the war grew closer, the need for an aircraft detection was critical. David realized the advantages of a pulsed system, and in October 1938 he designed a 50 MHz, pulse-modulated system with a peak-pulse power of 12 kW. This was built by the firm SADIR.[61]

France declared war on Germany on September 1, 1939, and there was a great need for an early-warning detection system. The SADIR system was taken to near Toulon, and detected and measured the range of invading aircraft as far as 55 km (34 mi). The SFR pulsed system was set up near Paris where it detected aircraft at ranges up to 130 km (81 mi). However, the German advance was overwhelming and emergency measures had to be taken; it was too late for France to develop radars alone and it was decided that her breakthroughs would be shared with her allies.

In mid-1940, Maurice Ponte, from the laboratories of CSF in Paris, presented a cavity magnetron designed by Henri Gutton at SFR (see above) to the GEC laboratories at Wembley, Britain. This magnetron was designed for pulsed operation at a wavelength of 16 cm. Unlike other magnetron designs to that day, such as the Boots and Randall magnetron (see British contributions above), this tube used an oxide-coated cathode with a peak power output of 1 kW, demonstrating that oxide cathodes were the solution for producing high-power pulses at short wavelengths, a problem which had eluded British and American researchers for years. The significance this event was underlined by Eric Megaw, in a 1946 review of early radar developments: "This was the starting point of the use of the oxide cathode in practically all our subsequent pulsed transmitting waves and as such was a significant contribution to British radar. The date was the 8th May 1940".[62] A tweaked version of this magnetron reached a peak output of 10 kW by August 1940. It was that model which, in turn, was handed to the Americans as a token of good faith[63] during the negotiations made by the Tizard delegation in 1940 to obtain from the U.S. the resources necessary for Britain to exploit the full military potential of her research and development work.

Italy[edit]

Guglielmo Marconi initiated the research in Italy on radio-based detection technology. In 1933, while participating with his Italian firm in experiments with a 600 MHz communications link across Rome, he noted transmission disturbances caused by moving objects adjacent to its path. This led to the development at his laboratory at Cornegliano of a 330-MHz (0.91-m) CW Doppler detection system that he called radioecometro. Barkhausen-Kurz tubes were used in both the transmitter and receiver.

In May 1935, Marconi demonstrated his system to the Fascist dictator Benito Mussolini and members of the military General Staff; however the output power was insufficient for military use. While Marconi's demonstration raised considerable interest, little more was done with his apparatus.

Mussolini directed that radio-based detection technology be further developed, and it was assigned to the Regio Instituto Electrotecnico e delle Comunicazioni (RIEC, Royal Institute for Electro-technics and Communications). The RIEC had been established in 1916 on the campus of the Italian Naval Academy in Livorno. Lieutenant Ugo Tiberio, a physics and radio-technology instructor at the Academy, was assigned to head the project on a part-time basis.[64]

Tiberio prepared a report on developing an experimental apparatus that he called telemetro radiofonico del rivelatore (RDT, Radio-Detector Telemetry). The report, submitted in mid-1936, included what was later known as the radar range equation. When the work got underway, Nello Carrara, a civilian physics instructor who had been doing research at the RIEC in microwaves,[65] was added to be responsible for developing the RDT transmitter.

Before the end of 1936, Tiberio and Carrara had demonstrated the EC-1, the first Italian RDT system. This had an FM transmitter operating at 200 MHz (1.5 m) with a single parabolic cylinder antenna. It detected by mixing the transmitted and the Doppler-shifted reflected signals, resulting in an audible tone.

The EC-1 did not provide a range measurement; to add this capability, development of a pulsed system was initiated in 1937. Captain Alfeo Brandimarte joined the group and primarily designed the first pulsed system, the EC-2. This operated at 175 MHz (1.7 m) and used a single antenna made with a number of equi-phased dipoles. The detected signal was intended to be displayed on an oscilloscope. There were many problems, and the system never reached the testing stage.

Work then turned to developing higher power and operating frequencies. Carrara, in cooperation with the firm FIVRE, developed a magnetron-like device. This was composed of a pair of triodes connected to a resonate cavity and produced 10 kW at 425 MHz (70 cm). It was used in designing two versions of the EC-3, one for shipboard and the other for coastal defense.[66]

Italy, joining Germany, entered WWII in June 1940 without an operational RDT. A breadboard of the EC-3 was built and tested from atop a building at the Academy, but most RDT work was stopped as direct support of the war took priority.

Others[edit]

In early 1939, the British Government invited representatives from the most technically advanced Commonwealth Nations to visit England for briefings and demonstrations on the highly secret RDF (radar) technology. Based on this, RDF developments were started in Australia, Canada, New Zealand, and South Africa by September 1939. In addition, this technology was independently developed in Hungary early in the war period.

In Australia, the Radiophysics Laboratory was established at Sydney University under the Council for Scientific and Industrial Research; John H. Piddington was responsible for RDF development. The first project was a 200-MHz (1.5-m) shore-defense system for the Australian Army. Designated ShD, this was first tested in September 1941, and eventually installed at 17 ports. Following the Japanese attack on Pearl Harbor, the Royal Australian Air Force urgently needed an air-warning system, and Piddington's team, using the ShD as a basis, put the AW Mark I together in five days. It was being installed in Darwin, Northern Territory, when Australia received the first Japanese attack on February 19, 1942. A short time later, it was converted to a light-weight transportable version, the LW-AW Mark II; this was used by the Australian forces, as well as the U.S. Army, in early island landings in the South Pacific.[67]

The early RDF developments in Canada were at the Radio Section of the National Research Council of Canada. Using commercial components and with essentially no further assistance from Britain, John Tasker Henderson led a team in developing the Night Watchman, a surface-warning system for the Royal Canadian Navy to protect the entrance to the Halifax Harbour. Successfully tested in July 1940, this set operated at 200 MHz (1.5 m), had a 1 kW output with a pulse length of 0.5 μs, and used a relatively small, fixed antenna. This was followed by a ship-borne set designated Surface Warning 1st Canadian (SW1C) with the antenna hand-rotated through the use of a Chevrolet steering wheel in the operator's compartment. The SW1C was first tested at sea in mid-May 1941, but the performance was so poor compared to the Royal Navy's Model 271 ship-borne radar that the Royal Canadian Navy eventually adopted the British 271 in place of the SW1C.[68]

For coastal defense by the Canadian Army, a 200 MHz set with a transmitter similar to the Night Watchman was developed. Designated CD, it used a large, rotating antenna atop a 70-foot (21 m) wooden tower. The CD was put into operation in January 1942.[69]

Ernest Marsden represented New Zealand at the briefings in England, and then established two facilities for RDF development – one in Wellington at the Radio Section of the Central NZ Post Office, and another at Canterbury University College in Christchurch. Charles N. Watson-Munro led the development of land-based and airborne sets at Wellington, while Frederick W. G. White led the development of shipboard sets at Christchurch.

Before the end of 1939, the Wellington group had converted an existing 180-MHz (1.6-m), 1 kW transmitter to produce 2-μs pulses and tested it to detect large vessels at up to 30 km; this was designated CW (Coastal Watching). A similar set, designated CD (Coast Defense) used a CRT for display and had lobe-switching on the receiving antenna; this was deployed in Wellington in late 1940. A partially completed ASV 200 MHz set was brought from Britain by Marsden, and another group at Wellington built this into an aircraft set for the Royal New Zealand Air Force; this was first flown in early 1940. At Christchurch, there was a smaller staff and work went slower, but by July 1940, a 430-MHz (70-cm), 5 kW set was tested. Two types, designated SW (Ship Warning) and SWG (Ship Warning, Gunnery), were placed into service by the Royal New Zealand Navy starting in August 1941. In all some 44 types were developed in New Zealand during WWII.[70]

South Africa did not have a representative at the 1939 meetings in England, but in mid-September, as Ernest Marsden was returning by ship to New Zealand, Basil F. J. Schonland came aboard and received three days of briefings. Schonland, a world authority on lightning and Director of the Bernard Price Institute of Geophysics at Witwatersrand University, immediately started an RDF development using amateur radio components and Institute's lightning-monitoring equipment. Designated JB (for Johannesburg), the 90-MHz (3.3-m), 500-W mobile system was tested in November 1939, just two months after its start. The prototype was operated in Durban before the end of 1939, detecting ships and aircraft at distances up to 80 km, and by the next March a system was fielded by anti-aircraft brigades of the South African Defence Force.[71]

In Hungary, Zoltán Lajos Bay was a Professor of Physics at the Technical University of Budapest as well as the Research Director of Egyesült Izzolampa (IZZO), a radio and electrical manufacturing firm. In late 1942, IZZO was directed by the Minister of Defense to develop a radio-location (rádiólokáció, radar) system. Using journal papers on ionospheric measurements for information on pulsed transmission, Bay developed a system called Sas (Eagle) around existing communications hardware.

The Sas operated at 120 MHz (2.5 m) and was in a cabin with separate transmitting and receiving dipole arrays attached; the assembly was all on a rotatable platform. According to published records, the system was tested in 1944 atop Mount János and had a range of “better than 500 km”. A second Sas was installed at another location. There is no indication that either Sas installation was ever in regular service. After the war, Bay used a modified Sas to successfully bounce a signal off the moon.[72]

World War II radar[edit]

At the start of World War II in September 1939, both the United Kingdom and Germany knew of each other's ongoing efforts in radio navigation and its countermeasures – the "Battle of the beams". Also, both nations were generally aware of, and intensely interested in, the other's developments in radio-based detection and tracking, and engaged in an active campaign of espionage and false leaks about their respective equipment. By the time of the Battle of Britain, both sides were deploying range and direction-finding units (radars) and control stations as part of integrated air defense capability. However, the German Funkmessgerät (radio measuring device) systems could not assist in an offensive role and was thus not supported by Adolf Hitler. Also, the Luftwaffe did not sufficiently appreciate the importance of British Range and Direction Finding (RDF) stations as part of RAF's air defense capability, contributing to their failure.

While the United Kingdom and Germany led in pre-war advances in the use of radio for detection and tracking of aircraft, there were also developments in the United States, the Soviet Union, and Japan. Wartime systems in all of these nations will be summarized. The acronym RADAR (for RAdio Detection And Ranging) was coined by the U.S. Navy in 1940, and the subsequent name "radar" was soon widely used. The XAF and CXAM search radars were designed by the Naval Research Laboratory, and were the first operational radars in the US fleet, produced by RCA.

When France had just fallen to the Nazis and Britain had no money to develop the magnetron on a massive scale, Churchill agreed that Sir Henry Tizard should offer the magnetron to the Americans in exchange for their financial and industrial help (the Tizard Mission). An early 6 kW version, built in England by the General Electric Company Research Laboratories, Wembley, London (not to be confused with the similarly named American company General Electric), was given to the US government in September 1940. The British magnetron was a thousand times more powerful than the best American transmitter at the time and produced accurate pulses.[73] At the time the most powerful equivalent microwave producer available in the US (a klystron) had a power of only ten watts. The cavity magnetron was widely used during World War II in microwave radar equipment and is often credited with giving Allied radar a considerable performance advantage over German and Japanese radars, thus directly influencing the outcome of the war. It was later described by noted Historian James Phinney Baxter III as "The most valuable cargo ever brought to our shores".[74]

The Bell Telephone Laboratories made a producible version from the magnetron delivered to America by the Tizard Mission, and before the end of 1940, the Radiation Laboratory had been set up on the campus of the Massachusetts Institute of Technology to develop various types of radar using the magnetron. By early 1941, portable centimetric airborne radars were being tested in American and British aircraft.[73] In late 1941, the Telecommunications Research Establishment in Great Britain used the magnetron to develop a revolutionary airborne, ground-mapping radar codenamed H2S. The H2S radar was in part developed by Alan Blumlein and Bernard Lovell. The magnetron radars used by the US and Britain could spot the periscope of a U-boat

Post-war radar[edit]

World War II, which gave impetus to the great surge in radar development, ended between the Allies and Germany in May 1945, followed by Japan in August. With this, radar activities in Germany and Japan ceased for a number of years. In other countries, particularly the United States, Britain, and the USSR, the politically unstable post-war years saw continued radar improvements for military applications. In fact, these three nations all made significant efforts in bringing scientists and engineers from Germany to work in their weapon programs; in the U.S., this was under Operation Paperclip.

Even before the end of the war, various project directed toward non-military applications of radar and closely related technologies were initiated. The US Army Air Forces and the British RAF had made wartime advances in using radar for handling aircraft landing, and this was rapidly expanded into the civil sector. The field of radio astronomy was one of the related technologies; although discovered before the war, it immediately flourished in the late 1940s with many scientists around the world establishing new careers based on their radar experience.

Four techniques, highly important in post-war radars, were matured in the late 1940s-early 1950s: pulse Doppler, monopulse, phased array, and synthetic aperture; the first three were known and even used during wartime developments, but were matured later.

  • Pulse-Doppler radar (often known as moving target indication or MTI), uses the Doppler-shifted signals from targets to better detect moving targets in the presence of clutter.[75]
  • Monopulse radar (also called simultaneous lobing) was conceived by Robert Page at the NRL in 1943. With this, the system derives error-angle information from a single pulse, greatly improving the tracking accuracy.[76]
  • Phased-array radar has the many segments of a large antenna separately controlled, allowing the beam to be quickly directed. This greatly reduces the time necessary to change the beam direction from one point to another, allowing almost simultaneous tracking of multiple targets while maintaining overall surveillance.[77]
  • Synthetic-aperture radar (SAR), was invented in the early 1950s at Goodyear Aircraft Corporation. Using a single, relatively small antenna carried on an aircraft, a SAR combines the returns from each pulse to produce a high-resolution image of the terrain comparable to that obtained by a much larger antenna. SAR has wide applications, particularly in mapping and remote sensing.[78]

One of the early applications of digital computers was in switching the signal phase in elements of large phased-array antennas. As smaller computers came into being, these were quickly applied to digital signal processing using algorithms for improving radar performance.

Other advances in radar systems and applications in the decades following WWII are far too many to be included herein. The following sections are intended to provide representative samples.

Military radars[edit]

In the United States, the Rad Lab at MIT officially closed at the end of 1945. The Naval Research Laboratory (NRL) and the Army's Evans Signal Laboratory continued with new activities in centimeter radar development. The United States Air Force (USAF) – separated from the Army in 1946 – concentrated radar research at their Cambridge Research Center (CRC) at Hanscom Field, Massachusetts. In 1951, MIT opened the Lincoln Laboratory for joint developments with the CRC. While the Bell Telephone Laboratories embarked on major communications upgrades, they continued with the Army in radar for their ongoing Nike air-defense program

In Britain, the RAF's Telecommunications Research Establishment (TRE) and the Army's Radar Research and Development Establishment (RRDE) both continued at reduced levels at Malvern, Worcestershire, then in 1953 were combined to form the Radar Research Establishment. In 1948, all of the Royal Navy's radio and radar R&D activities were combined to form the Admiralty Signal and Radar Establishment, located near Portsmouth, Hampshire. The USSR, although devastated by the war, immediately embarked on the development of new weapons, including radars.

During the Cold War period following WWII, the primary "axis" of combat shifted to lie between the United States and the Soviet Union. By 1949, both sides had nuclear weapons carried by bombers. To provide early warning of an attack, both deployed huge radar networks of increasing sophistication at ever-more remote locations. In the West, the first such system was the Pinetree Line, deployed across Canada in the early 1950s, backed up with radar pickets on ships and oil platforms off the east and west coasts.

The Pinetree Line initially used vintage pulsed radars and was soon supplemented with the Mid-Canada Line (MCL). Soviet technology improvements made these Lines inadequate and, in a construction project involving 25,000 persons, the Distant Early Warning Line (DEW Line) was completed in 1957. Stretching from Alaska to Baffin Island and covering over 6,000 miles (9,700 km), the DEW Line consisted of 63 stations with AN/FPS-19 high-power, pulsed, L-Band radars, most augmented by AN/FPS-23 pulse-Doppler systems. The Soviet Unit tested its first Intercontinental Ballistic Missile (ICBM) in August 1957, and in a few years the early-warning role was passed almost entirely to the more capable DEW Line.

Both the U.S. and the Soviet Union then had ICBMs with nuclear warheads, and each began the development of a major anti-ballistic missile (ABM) system. In the USSR, this was the Fakel V-1000, and for this they developed powerful radar systems. This was eventually deployed around Moscow as the A-35 anti-ballistic missile system, supported by radars designated by NATO as the Cat House, Dog House, and Hen House.

In 1957, the U.S. Army initiated an ABM system first called Nike-X; this passed through several names, eventually becoming the Safeguard Program. For this, there was a long-range Perimeter Acquisition Radar (PAR) and a shorter-range, more precise Missile Site Radar (MSR).[79]

The PAR was housed in a 128-foot (39 m)-high nuclear-hardened building with one face sloping 25 degrees facing north. This contained 6,888 antenna elements separated in transmitting and receiving phased arrays. The L-Band transmitter used 128 long-life traveling-wave tubes (TWTs), having a combined power in the megawatt range The PAR could detect incoming missiles outside the atmosphere at distances up to 1,800 miles (2,900 km).

The MSR had an 80-foot (24 m), truncated pyramid structure, with each face holding a phased-array antenna 13 feet (4.0 m) in diameter and containing 5,001 array elements used for both transmitting and receiving. Operating in the S-Band, the transmitter used two klystrons functioning in parallel, each with megawatt-level power. The MSR could search for targets from all directions, acquiring them at up to 300 miles (480 km) range.

One Safeguard site, intended to defend Minuteman ICBM missile silos near the Grand Forks AFB in North Dakota, was finally completed in October 1975, but the U.S. Congress withdrew all funding after it was operational but a single day. During the following decades, the U.S. Army and the U.S. Air Force developed a variety of large radar systems, but the long-serving BTL gave up military development work in the 1970s.

A modern radar developed by of the U.S. Navy that should be noted is the AN/SPY-1. First fielded in 1973, this S-Band, 6 MW system has gone through a number of variants and is a major component of the Aegis Combat System. An automatic detect-and-track system, it is computer controlled using four complementary three-dimensional passive electronically scanned array antennas to provide hemispherical coverage.

Radar signals, traveling with line-of-sight propagation, normally have a range to ground targets limited by the visible horizon, or less than about 10 miles (16 km). Airborne targets can be detected by ground-level radars at greater ranges, but, at best, several hundred miles. Since the beginning of radio, it had been known that signals of appropriate frequencies (3 to 30 MHz) could be “bounced” from the ionosphere and received at considerable distances. As long-range bombers and missiles came into being, there was a need to have radars give early warnings at great ranges. In the early 1950s, a team at the Naval Research Laboratory came up with the Over-the-Horizon (OTH) radar for this purpose.

To distinguish targets from other reflections, it was necessary to use a phase-Doppler system. Very sensitive receivers with low-noise amplifiers had to be developed. Since the signal going to the target and returning had a propagation loss proportional to the range raised to the fourth power, a powerful transmitter and large antennas were required. A digital computer with considerable capability (new at that time) was necessary for analyzing the data. In 1950, their first experimental system was able to detect rocket launches 600 miles (970 km) away at Cape Canaveral, and the cloud from a nuclear explosion in Nevada 1,700 miles (2,700 km) distant.

In the early 1970s, a joint American-British project, code named Cobra Mist, used a 10-MW OTH radar at Orfordness (the birthplace of British radar), England, in an attempt to detect aircraft and missile launchings over the Western USSR. Because of US-USSR ABM agreements, this was abandoned within two years.[80] In the same time period, the Soviets were developing a similar system; this successfully detected a missile launch at 2,500 km (1,600 mi). By 1976, this had matured into an operational system named Duga (“Arc” in English), but known to western intelligence as Steel Yard and called Woodpecker by radio amateurs and others who suffered from its interference – the transmitter was estimated to have a power of 10 MW.[81] Australia, Canada, and France also developed OTH radar systems.

With the advent of satellites with early-warning capabilities, the military lost most of its interest in OTH radars. However, in recent years, this technology has been reactivated for detecting and tracking ocean shipping in applications such as maritime reconnaissance and drug enforcement.

Systems using an alternate technology have also been developed for over-the-horizon detection. Due to diffraction, electromagnetic surface waves are scattered to the rear of objects, and these signals can be detected in a direction opposite from high-powered transmissions. Called OTH-SW (SW for Surface Wave), Russia is using such a system to monitor the Sea of Japan, and Canada has a system for coastal surveillance.

Civil aviation radars[edit]

The post-war years saw the beginning of a revolutionary development in Air Traffic Control (ATC) – the introduction of radar. In 1946, the Civil Aeronautics Administration (CAA) unveiled an experimental radar-equipped tower for control of civil flights. By 1952, the CAA had begun its first routine use of radar for approach and departure control. Four years later, it placed a large order for long-range radars for use in en route ATC; these had the capability, at higher altitudes, to see aircraft within 200 nautical miles (370 km). In 1960, it became required for aircraft flying in certain areas to carry a radar transponder that identified the aircraft and helped improve radar performance. Since 1966, the responsible agency has been called the Federal Aviation Administration (FAA).

A Terminal Radar Approach Control (TRACON) is an ATC facility usually located within the vicinity of a large airport. In the US Air Force it is known as RAPCON (Radar Approach Control), and in the US Navy as a RATCF (Radar Air Traffic Control Facility). Typically, the TRACON controls aircraft within a 30 to 50 nautical mile (56 to 93 km) radius of the airport at an altitude between 10,000 and 15,000 feet (3,000 to 4,600 m). This uses one or more Airport Surveillance Radars (ASR-8, 9 and 11, ASR-7 is obsolete), sweeping the sky once every few seconds. These Primary ASR radars are typically paired with secondary radars (Air Traffic Radar Beacon Interrogators, or ATCBI) of the ATCBI-5, Mode S or MSSR types. Unlike primary radar, secondary radar relies upon an aircraft based transponder, which receives an interrogation from the ground and replies with an appropriate digital code which includes the aircraft id and reports the aircraft's altitude. The principle is similar to the military IFF Identification friend or foe. The secondary radar antenna array rides atop the primary radar dish at the radar site, with both rotating at approximately 12 revolutions per minute.

The Digital Airport Surveillance Radar (DASR) is a newer TRACON radar system, replacing the old analog systems with digital technology. The civilian nomenclature for these radars is the ASR-9 and the ASR-11, and AN/GPN-30 is used by the military.

In the ASR-11, two radar systems are included. The primary is an S-Band (~2.8 GHz) system with 25 kW pulse power. It provides 3-D tracking of target aircraft and also measures rainfall intensity. The secondary is a P-Band (~1.05 GHz) system with a peak-power of about 25 kW. It uses a transponder set to interrogate aircraft and receive operational data. The antennas for both systems rotate atop a tall tower.[82]

Weather radar[edit]

170px-David_Atlas_Weather_radar_pionneer

During World War II, military radar operators noticed noise in returned echoes due to weather elements like rain, snow, and sleet. Just after the war, military scientists returned to civilian life or continued in the Armed Forces and pursued their work in developing a use for those echoes. In the United States, David Atlas,[83] for the Air Force group at first, and later for MIT, developed the first operational weather radars. In Canada, J.S. Marshall and R.H. Douglas formed the "Stormy Weather Group[84] " in Montreal. Marshall and his doctoral student Walter Palmer are well known for their work on the drop size distribution in mid-latitude rain that led to understanding of the Z-R relation, which correlates a given radar reflectivity with the rate at which water is falling on the ground. In the United Kingdom, research continued to study the radar echo patterns and weather elements such as stratiform rain and convective clouds, and experiments were done to evaluate the potential of different wavelengths from 1 to 10 centimetres.

Between 1950 and 1980, reflectivity radars, which measure position and intensity of precipitation, were built by weather services around the world. In United States, the U.S. Weather Bureau, established in 1870 with the specific mission of to provide meteorological observations and giving notice of approaching storms, developed the WSR-1 (Weather Surveillance Radar-1), one of the first weather radars. This was a modified version of the AN/APS-2F radar, which the Weather Bureau acquired from the Navy. The WSR-1A, WSR-3, and WSR-4 were also variants of this radar.[85] This was followed by the WSR-57 (Weather Surveillance Radar – 1957) was the first weather radar designed specifically for a national warning network. Using WWII technology based on vacuum tubes, it gave only coarse reflectivity data and no velocity information. Operating at 2.89 GHz (S-Band), it had a peak-power of 410 kW and a maximum range of about 580 mi (930 km). AN/FPS-41 was the military designation for the WSR-57.

The early meteorologists had to watch a cathode ray tube. During the 1970s, radars began to be standardized and organized into larger networks. The next significant change in the United States was the WSR-74 series, beginning operations in 1974. There were two types: the WSR-74S, for replacements and filling gaps in the WSR-57 national network, and the WSR-74C, primarily for local use. Both were transistor-based, and their primary technical difference was indicated by the letter, S band (better suited for long range) and C band, respectively. Until the 1990s, there were 128 of the WSR-57 and WSR-74 model radars were spread across that country.

The first devices to capture radar images were developed during the same period. The number of scanned angles was increased to get a three-dimensional view of the precipitation, so that horizontal cross-sections (CAPPI) and vertical ones could be performed. Studies of the organization of thunderstorms were then possible for the Alberta Hail Project in Canada and National Severe Storms Laboratory (NSSL) in the US in particular. The NSSL, created in 1964, began experimentation on dual polarization signals and on Doppler effect uses. In May 1973, a tornado devastated Union City, Oklahoma, just west of Oklahoma City. For the first time, a Dopplerized 10-cm wavelength radar from NSSL documented the entire life cycle of the tornado.[86] The researchers discovered a mesoscale rotation in the cloud aloft before the tornado touched the ground : the tornadic vortex signature. NSSL's research helped convince the National Weather Service that Doppler radar was a crucial forecasting tool.[86]

Between 1980 and 2000, weather radar networks became the norm in North America, Europe, Japan and other developed countries. Conventional radars were replaced by Doppler radars, which in addition to position and intensity of could track the relative velocity of the particles in the air. In the United States, the construction of a network consisting of 10 cm (4 in) wavelength radars, called NEXRAD or WSR-88D (Weather Service Radar 1988 Doppler), was started in 1988 following NSSL's research.[86] In Canada, Environment Canada constructed the King City station,[87] with a five centimeter research Doppler radar, by 1

Administration has been experimenting with phased-array radar as a replacement for conventional parabolic antenna to provide more time resolution in atmospheric sounding. This would be very important in severe thunderstorms as their evolution can be better evaluated with more timely data.

Also in 2003, the National Science Foundation established the Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere, "CASA", a multidisciplinary, multi-university collaboration of engineers, computer scientists, meteorologists, and sociologists to conduct fundamental research, develop enabling technology, and deploy prototype engineering systems designed to augment existing radar systems by sampling the generally undersampled lower troposphere with inexpensive, fast scanning, dual polarization, mechanically scanned and phased array radars.

Mapping radar[edit]

The plan position indicator, dating from the early days of radar and still the most common type of display, provides a map of the targets surrounding the radar location. If the radar antenna on an aircraft is aimed downward, a map of the terrain is generated, and the larger the antenna, the greater the image resolution. After centimeter radar came into being, downward-looking radars – the H2S ( L-Band) and H2X (C-Band) – provided real-time maps used by the U.S. and Britain in bombing runs over Europe at night and through dense clouds.

In 1951, Carl Wiley led a team at Goodyear Aircraft Corporation (later Goodyear Aerospace) in developing a technique for greatly expanding and improving the resolution of radar-generated images. Called synthetic aperture radar (SAR), an ordinary-sized antenna fixed to the side of an aircraft is used with highly complex signal processing to give an image that would otherwise require a much larger, scanning antenna; thus, the name synthetic aperture. As each pulse is emitted, it is radiated over a lateral band onto the terrain. The return is spread in time, due to reflections from features at different distances. Motion of the vehicle along the flight path gives the horizontal increments. The amplitude and phase of returns are combined by the signal processor using Fourier transform techniques in forming the image. The overall technique is closely akin to optical holography.

Through the years, many variations of the SAR have been made with diversified applications resulting. In initial systems, the signal processing was too complex for on-board operation; the signals were recorded and processed later. Processors using optical techniques were then tried for generating real-time images, but advances in high-speed electronics now allow on-board processes for most applications. Early systems gave a resolution in tens of meters, but more recent airborne systems provide resolutions to about 10 cm. Current ultra-wideband systems have resolutions of a few millimeters.

Other radars and applications[edit]

There are many other post-war radar systems and applications. Only a few will be noted.

Radar gun[edit]

The most widespread radar device today is undoubtedly the radar gun. This is a small, usually hand-held, Doppler radar that is used to detect the speed of objects, especially trucks and automobiles in regulating traffic, as well as pitched baseballs, runners, or other moving objects in sports. This device can also be used to measure the surface speed of water and continuously manufactured materials. A radar gun does not return information regarding the object's position; it uses the Doppler effect to measure the speed of a target. First developed in 1954, most radar guns operate with very low power in the X or Ku Bands. Some use infrared radiation or laser light; these are usually called LIDAR. A related technology for velocity measurements in flowing liquids or gasses is called laser Doppler velocimetry; this technology dates from the mid-1960s.

Impulse radar[edit]

As pulsed radars were initially being developed, the use of very narrow pulses was examined. The pulse length governs the accuracy of distance measurement by radar – the shorter the pulse, the greater the precision. Also, for a given pulse repetition frequency (PRF), a shorter pulse results in a higher peak power. Harmonic analysis shows that the narrower the pulse, the wider the band of frequencies that contain the energy, leading to such systems also being called wide-band radars. In the early days, the electronics for generating and receiving these pulses was not available; thus, essentially no applications of this were initially made.

By the 1970s, advances in electronics led to renewed interest in what was often called short-pulse radar. With further advances, it became practical to generate pulses having a width on the same order as the period of the RF carrier (T = 1/f). This is now generally called impulse radar.

The first significant application of this technology was in ground-penetrating radar (GPR). Developed in the 1970s, GPR is now used for structural foundation analysis, archeological mapping, treasure hunting, unexploded ordnance identification, and other shallow investigations. This is possible because impulse radar can concisely locate the boundaries between the general media (the soil) and the desired target. The results, however, are non-unique and are highly dependent upon the skill of the operator and the subsequent interpretation of the data.

In dry or otherwise favorable soil and rock, penetration up to 300 feet (91 m) is often possible. For distance measurements at these short ranges, the transmitted pulse is usually only one radio-frequency cycle in duration; With a 100 MHz carrier and a PRF of 10 kHz (typical parameters), the pulse duration is only 10 ns (nanosecond). leading to the "impulse" designation. A variety of GPR systems are commercially available in back-pack and wheeled-cart versions with pulse-power up to a kilowatt.[90]

With continued development of electronics, systems with pulse durations measured in picoseconds became possible. Applications are as varied as security and motion sensors, building stud-finders, collision-warning devices, and cardiac-dynamics monitors. Some of these devices are matchbox sized, including a long-life power source.[91]

Radar astronomy[edit]

As radar was being developed, astronomers considered its application in making observations of the Moon and other near-by extraterrestrial objects. In 1944, Zoltán Lajos Bay had this as a major objective as he developed a radar in Hungary. His radar telescope was taken away by the conquering Soviet army and had to be rebuilt, thus delaying the experiment. Under Project Diana conducted by the Army's Evans Signal Laboratory in New Jersey, a modified SCR-271 radar (the fixed-position version of the SCR-270) operating at 110 MHz with 3 kW peak-power, was used in receiving echoes from the Moon on January 10, 1946.[92] Zoltán Bay accomplished this on the following February 6.[93]

Radio astronomy also had its start following WWII, and many scientists involved in radar development then entered this field. A number of radio observatories were constructed during the following years; however, because of the additional cost and complexity of involving transmitters and associated receiving equipment, very few were dedicated to radar astronomy. In fact, essentially all major radar astronomy activities have been conducted as adjuncts to radio astronomy observatories.

The radio telescope at the Arecibo Observatory, opened in 1963, is the largest in the world. Owned by the U.S. National Science Foundation and contractor operated, it is used primarily for radio astronomy, but equipment is available for radar astronomy. This includes transmitters operating at 47 MHz, 439 MHz, and 2.38 GHz, all with very-high pulse power. It has a 305-m (1,000-ft) primary reflector fixed in position; the secondary reflector is on tracks to allow precise pointing to different parts of the sky. Many significant scientific discoveries have been made using the Arecibo radar telescope, including mapping of surface roughness of Mars and observations of Saturns and its largest moon, Titan. In 1989, the observatory radar-imaged an asteroid for the first time in history.

Several spacecraft orbiting the Moon, Mercury, Venus, Mars, and Saturn have carried radars for surface mapping; a ground-penetration radar was carried on the Mars Express mission. Radar systems on a number of aircraft and orbiting spacecraft have mapped the entire Earth for various purposes; on the Shuttle Radar Topography Mission, the entire planet was mapped at a 30-m resolution.

The Jodrell Bank Observatory, an operation of the University of Manchester in Britain, was originally started by Bernard Lovell to be a radar astronomy facility. It initially used a war-surplus GL-II radar system operating at 71 MHz (4.2 m). The first observations were of ionized trails in the Geminids meteor shower during December 1945. While the facility soon evolved to become the third largest radio observatory in the world, some radar astronomy continued. The largest (250-ft or 76-m in diameter) of their three fully steerable radio telescopes became operational just in time to radar track Sputnik 1, the first artificial satellite, in October 1957.[94]

See also[edit]

References[edit]

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  58. ^ French patent Archived 2009-01-16 at the Wayback Machine (no. 788.795, "New system of location of obstacles and its applications")
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  61. ^ David, Pierre; Le Radar (The Radar), Presses Universitaires de France, 1949 (in French)
  62. ^ Megaw, Eric C. S.; “The High-Power Magnetron: A Review of Early Developments”, Journal of the IEE, vol. 93, 1946, p. 928, see copy at http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5299357
  63. ^ Paul A. Redhead, The invention of the cavity magnetron and its introduction into Canada and the U.S.A., PHYSICS IN CANADA, November/December 2001, "Archived copy" (PDF). Archived from the original (PDF) on 2012-02-13. Retrieved 2008-10-10.CS1 maint: archived copy as title (link)
  64. ^ Calamia, M., and R. Palandri; “The History of the Italian Radio Detector Telemetro”, in Radar Development to 1945, ed. by Russell Burns, Peter Peregrinus, 1988, pp. 97–105
  65. ^ Carrara, N.; “The detection of microwaves”, Proc. IRE, vol. 20, Oct. 1932, pp. 1615–1625
  66. ^ Tiberio, U.; “Some historical data concerning the first Italian naval radar”, IEEE Trans. AES, vol. 15, Sept., 1979, p. 733
  67. ^ Sinnott, D. H.; “Radar Development in Australia: 1939 to Present”, Proc. of IEEE 2005 International Radar Conference, 9–12 May, pp. 5–9
  68. ^ Lamb, James B. (1987). On the triangle run. Toronto: Totem Books. pp. 26–28. ISBN 978-0-00-217909-6.
  69. ^ Moorcroft, Don; “Origins of Radar-based Research in Canada”, Univ. Western Ontario, 2002; "Archived copy". Archived from the original on 2014-11-29. Retrieved 2014-12-14.CS1 maint: archived copy as title (link)
  70. ^ Unwin, R. S.; “Development of Radar in New Zealand in World War II”, IEEE Antennas and Propagation Magazine, vol. 34, June, pp.31–33, 1992
  71. ^ Hewitt, F. J.; “South Africa’s Role in the Development and Use of Radar in World War II”, Military History Journal, vol. 3, no, 3, June 1975; "Archived copy". Archived from the original on 2010-01-27. Retrieved 2010-02-13.CS1 maint: archived copy as title (link)
  72. ^ Renner, Peter; “The Role of the Hungarian Engineers in the Development of Radar Systems”, Periodica Polytechnica Ser. Soc. Man. Sci, Vol. 12, p. 277, 2004; "Archived copy" (PDF). Archived from the original (PDF) on 2011-07-19. Retrieved 2010-02-13.CS1 maint: archived copy as title (link)
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  74. ^ James Phinney Baxter III (Official Historian of the Office of Scientific Research and Development), Scientists Against Time (Boston: Little, Brown, and Co., 1946), page 142.
  75. ^ Barlow, E. J.; “Doppler Radar”, Proc. IRE, vol. 37, pp. 340–355, April 1949
  76. ^ Page, R. M.; “Monopulse Radar”, op. cet.
  77. ^ Von Aulock, W. H.; “Properties of Phased Arrays”, Proc. IRE, vol. 48, pp. 1715–1727, Oct., 1960
  78. ^ ”Airborne Synthetic Aperture Radar”; "Archived copy". Archived from the original on 2012-04-14. Retrieved 2010-03-11.CS1 maint: archived copy as title (link)
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  85. ^ Whiton, Roger C., et al. "History of Operational Use of Weather Radar by U.S. Weather Services. Part I: The Pre-NEXRAD Era"; Weather and Forecasting, vol. 13, no. 2, pp. 219–243, 19 Feb. 1998; http://ams.allenpress.com/amsonline/?request=get-document&doi=10.1175%2F1520-0434(1998)013%3C0219:HOOUOW%3E2.0.CO%3B2[permanent dead link]
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Further reading[edit]

  • Blanchard, Yves, Le radar. 1904–2004 : Histoire d'un siècle d'innovations techniques et opérationnelles, éditions Ellipses,(in French)
  • Bowen, E. G.; “The development of airborne radar in Great Britain 1935–1945”, in Radar Development to 1945, ed. by Russell Burns; Peter Peregrinus, 1988, ISBN 0-86341-139-8
  • Bowen, E. G., Radar Days, Institute of Physics Publishing, Bristol, 1987, ISBN 0-7503-0586-X
  • Bragg, Michael., RDF1 The Location of Aircraft by Radio Methods 1935–1945, Hawkhead Publishing, 1988, ISBN 0-9531544-0-8
  • Brown, Jim, Radar – how it all began, Janus Pub., 1996, ISBN 1-85756-212-7
  • Brown, Louis, A Radar History of World War 2 – Technical and Military Imperatives, Institute of Physics Publishing, 1999, ISBN 0-7503-0659-9
  • Buderi, Robert: The invention that changed the world: the story of radar from war to peace, Simon & Schuster, 1996, ISBN 0-349-11068-9
  • Burns, Peter (editor): Radar Development to 1945, Peter Peregrinus Ltd., 1988, ISBN 0-86341-139-8
  • Clark, Ronald W., Tizard, MIT Press, 1965, ISBN 0-262-03010-1 (An authorized biography of radar's champion in the 1930s.)
  • Dummer, G. W. A., Electronic Inventions and Discoveries, Elsevier, 1976, Pergamon, 1977, ISBN 0-08-020982-3
  • Erickson, John; “Radio-location and the air defense problem: The design and development of Soviet Radar 1934–40”, Social Studies of Science, vol. 2, p. 241, 1972
  • Frank, Sir Charles, Operation Epsilon: The Farm Hall Transcripts U. Cal. Press, 1993 (How German scientists dealt with Nazism.)
  • Guerlac, Henry E., Radar in World War II,(in two volumes), Tomash Publishers / Am Inst. of Physics, 1987, ISBN 0-88318-486-9
  • Hanbury Brown, Robert, Boffin: A Personal Story of the early Days of Radar and Radio Astronomy and Quantum Optics, Taylor and Francis, 1991, ISBN 978-0-750-30130-5
  • Howse, Derek, Radar At Sea The Royal Navy in World War 2, Naval Institute Press, Annapolis, Maryland, USA, 1993, ISBN 1-55750-704-X
  • Jones, R. V., Most Secret War, Hamish Hamilton, 1978, ISBN 0-340-24169-1 (Account of British Scientific Intelligence between 1939 and 1945, working to anticipate Germany's radar and other developments.)
  • Kroge, Harry von, GEMA: Birthplace of German Radar and Sonar, translated by Louis Brown, Inst. of Physics Publishing, 2000, ISBN 0-471-24698-0
  • Latham, Colin, and Anne Stobbs, Radar A Wartime Miracle, Sutton Publishing Ltd, 1996, ISBN 0-7509-1643-5 (A history of radar in the UK during WWII told by the men and women who worked on it.)
  • Latham, Colin, and Anne Stobbs, The Birth of British Radar: The Memoirs of Arnold 'Skip' Wilkins, 2nd Ed., Radio Society of Great Britain, 2006, ISBN 9781-9050-8675-7
  • Lovell, Sir Bernard Lovel, Echoes of War – The History of H2S, Adam Hilger, 1991, ISBN 0-85274-317-3
  • Nakagawa, Yasudo; Japanese Radar and Related Weapons of World War II, translated and edited by Louis Brown, John Bryant, and Naohiko Koizumi, Aegean Park Press, 1997, ISBN 0-89412-271-1
  • Pritchard, David., The Radar War Germany's Pioneering Achievement 1904–1945 Patrick Stephens Ltd, Wellingborough 1989, ISBN 1-85260-246-5
  • Rawnsley, C. F., and Robert Wright, Night Fighter, Mass Market Paperback, 1998
  • Sayer, A. P., Army Radar – historical monograph, War Office, 1950
  • Swords, Seán S., Technical History of the Beginnings of Radar, IEE/Peter Peregrinus, 1986, ISBN 0-86341-043-X
  • Watson, Raymond C., Jr. Radar Origins Worldwide: History of Its Evolution in 13 Nations Through World War II. Trafford Pub., 2009, ISBN 978-1-4269-2111-7
  • Watson-Watt, Sir Robert, The Pulse of Radar, Dial Press, 1959, (no ISBN) (An autobiography of Sir Robert Watson-Watt)
  • Zimmerman, David., Britain's Shield Radar and the Defeat of the Luftwaffe, Sutton Publishing, 2001, ISBN 0-7509-1799-7

External links[edit]

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Cockroaches in popular culture

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Because of their long, persistent association with humans, cockroaches are frequently referred to in art, literature, folk tales and theater and film. In Western culture, cockroaches are often depicted as vile and dirty pests. Their size, long antennae, shiny appearance and spiny legs make them disgusting to many humans, sometimes even to the point of phobic responses.[1][2] This is borne out in many depictions of cockroaches, from political versions of the song "La Cucaracha" where political opponents are compared to cockroaches, through the 1982 movie Creepshow and TV shows such as The X-Files, to the Hutu extremists' reference to the Tutsi minority as cockroaches during the Rwandan genocide in 1994[citation needed] and the controversial cartoons published in the "Iran weekly magazine" in 2006 which implied a comparison between Iranian Azeris and cockroaches[citation needed]. In Dutch Soccer the term "kakkerlakken" (Dutch for cockroaches) is used as a colloquial, often derogatory term for the supporters of Feyenoord[citation needed].

Not all depictions of cockroaches are purely negative, however. In the Pixar film WALL-E, a cockroach that has survived all humanity is the lead character's (a robot's) best friend, and waits patiently on him to return. The same cockroach survives getting squished twice. In the film Joe's Apartment, the cockroaches help the titular hero, and the narrator of the book Archy and Mehitabel is a sympathetic cockroach. In the book Revolt of the Cockroach People, an autobiographical novel by Oscar Zeta Acosta, cockroaches are used as a metaphor for oppressed and downtrodden minorities in US society in the 1960s and 1970s. The image of cockroaches as resilient also leads people to compare themselves to cockroaches. Madonna has famously quoted, "I am a survivor. I am like a cockroach, you just can't get rid of me."[3] "Cockroach", or some variant of it is also used as a nickname, for example Boxing coach Freddie Roach, who was nicknamed La Cucaracha (The Cockroach) when he was still competing as a fighter.

For on-screen moments, TV shows and movies often employ the Madagascar hissing cockroach due to its large size and very slow speed.

In film

  • Gagamboy — There is a super villain named Kuanting (Cockroach Man) portrayed by Jay Manalo who later became Gagamboy (portrayed by Vhong Navarro)'s nemesis who accidentally ate a cockroach in a sandwich.
  • Joe's Apartment — The bugs are cheerful, swinging party-goers who help the titular human hero.
  • Twilight of the Cockroaches — A hybrid anime/live-action Japanese film featuring a society of cockroaches living in a bachelor's apartment that faces extermination when a cockroach-phobic woman moves in.
  • Creepshow — Swarms of them terrorize a cantankerous and verminophobic old man in the segment, "They're Creeping Up On You."
  • Damnation Alley — A post-apocalyptic Salt Lake City, Utah is infected with a four-inch long, flesh-eating mutant variety (played by the Madagascar hissing cockroach).
  • Mimic — Diseased cockroaches are the target of the genetically-altered titular species.
  • Bug — also starred Madagascar hissing cockroaches, this time able to produce fire from their abdomens, wreaking havoc.
  • Men in Black — Edgar the Bug's actions threaten to lead to the destruction of the Earth.
  • An American Tail — the chief villain, Warren T. Rat, carries with him a cockroach named Digit whom he forces to count his money and frequently abuses, even threatening to eat him at one point.
  • Godzilla vs. Gigan — both King Ghidorah and Gigan are controlled remotely by Nebulans, an alien race of giant cockroaches that inherited a waste planet after the dominant species on it polluted it into oblivion.
  • Scarface (1983 version) — Tony refers to Gaspar Gomez and the Diaz Brothers, rival gang leaders to Frank Lopez, as cockroaches in one of the film's most famous lines: "I'll bury those cock-a-roaches."
  • Pacific Heights — The Michael Keaton character breeds and releases cockroaches in the apartment building as part of his plan against the landlords.
  • A Nightmare on Elm Street 4: The Dream Master — Freddy Krueger kills Debbie by transforming her into a cockroach and trapping her inside a roach motel before crushing the trap.
  • WALL-E — WALL-E keeps a cockroach as his pet.
  • West Side Story — in both the Broadway musical (1957) and film (1961), the Jets, the Anglo-American gang, refers to the Sharks, the Puerto Rican gang, as cockroaches.
  • Enchanted — Cockroaches (and other pests) assist a princess with housecleaning duties such as scrubbing the bathtub.
  • Oggy and the Cockroaches: The Movie — features three fictional cockroaches as main characters. Their names are Dee Dee, Joey and Marky.
  • The Nest

In television

  • X-Files episode "War of the Coprophages", cockroaches are seen to group together to murder people. The character Dr. Berenbaum (based on the University of Illinois entomologist) suggests that it is actually swarms of cockroaches that are responsible for most UFO sightings because they can generate an electrostatic field which can be illuminated dependent on atmospheric conditions. In one of the scenes, a cockroach that escaped can be seen crawling over the camera, making it appear that the viewer's television has become infested. Though the shot was not planned, the producers decided to leave it in the episode.
  • ALF, Alf inadvertently releases a cockroach from his home planet in the house. When it is sprayed with insecticide, it grows bigger until it is large enough to eat him. He discovered by accident that a bottle of perfume could kill the cockroach.
  • The short-lived kids television show Freaky Stories was hosted by a cockroach named Larry.
  • Transformers Animated, an experiment on a cockroach goes wrong, causing it to grow and absorb everything in its path. Sari caught and damaging Prowl.
  • In the television show King of the Hill, the character Dale Gribble has been shown as a breeder of cockroaches. He attempts to breed a colony of Madagascar hissing cockroaches to do his bidding, theorizing that they will believe he is their mother and obey if he is the first thing they see when they hatch.
  • In the popular television show Heroes, cockroaches are often shown near the main antagonist of the series, Sylar. The series' creator Tim Kring has stated that, because of their ability to survive and adapt so well, cockroaches present the embodiment of evolution to him, so he included them because of the show's evolutionary theme.[4]
  • In The Cosby Show, Theo's friend is nicknamed Cockroach.
  • In the Family Guy episode "Screwed the Pooch", while at the motel Brian is being given a tour of his motel room. When the owner reaches the bathroom and states that they have a roach problem, he opens the door to reveal two giant roaches in gang attire threatening to cut them.
  • In All That Season 6 Episode 4, there is a skit about a game show called "Cockroaches in Your Pants" where Jerry Futile, the host, stuffs cockroaches down peoples pants.
  • Oggy and the Cockroaches features three anthropomorphic cockroaches as main characters. Their names are Dee Dee, Joey and Marky.
  • In The Powerpuff Girls episode "Insect Inside", an evil man named Roach Coach possesses a swarm of cockroaches as his pets and uses them to attack and rule the City of Townsville. After his defeat, Roach Coach turns out to be a sentient, talking cockroach that controls a mech resembling a human. Also, in the episode "Bubble Boy", Brick (Blossom's male counterpart) of the Rowdyruff Boys challenges Bubbles (disguised as Boomer) to eat a cockroach.
  • In Yin Yang Yo!, one of the main antagonists in the series is Carl the Evil Cockroach Wizard.
  • In Teenage Mutant Ninja Turtles, Donatello installed cameras on cockroaches to use as spying devices. One of these fell into a vat of mutagen, and transformed into a giant cockroach. Raphael was also revealed to have a paralysing fear of cockroaches, a fear he eventually learns to control.

In written works

  • In Franz Kafka's story The Metamorphosis, the character Gregor Samsa awakes to find himself transformed into a giant "vermin." Although the type of bug Gregor changes into is not specified, the physical description offered depicts a cockroach-like creature. This novel has been parodied in various ways, including at least two other published works: Marc Estrin's 2002 Insect Dreams: The Half Life of Gregor Samsa, where Gregor Samsa prospers despite his transformation, becoming an important figure in society, and Tyler Knox's 2006 noir comedy Kockroach in which a cockroach wakes up one morning as a man and becomes a leading gangster in Times Square during the 1950s.
  • Daniel Evan Weiss's novel The Roaches Have No King tells the story of a humanized colony of cockroaches, who swear revenge against their hosts for renovating the kitchen and thus preventing easy access to food supplies.
  • In Arabic and other eastern societies, sometimes a traditional method to protect books and scrolls was a metaphysical appeal to "Kabi:Kaj" (كبيبكج/كَبِيكَج), the "King of the Cockroaches." By appealing to the king to protect a manuscript, cockroaches of less nobility (or lesser insects) would refrain from intruding on documents which could be eaten by the king only. Since many manuscripts were made with fish-glue, starch-paste, leather and other edible substances, insect appetites were a constant problem to Arabic books and scrolls.[5] A similar technique from Syria was to name the first and last page of a document or manuscript "The Page of the King of the Cockroaches", in the hope that the Cockroach King will control all other insects. Translated appeals include "O Kabi:kaj, save the paper!", "O Kabi:kaj, save this book from the worms!" and "O Kabi:kaj, do not eat this paper!"[6] "In Maghribi manuscripts, the word appears in its evidently corrupt form, "Kaykataj" and is clearly used as a talisman... and mentions, after a certain Muhammad al-Samiri, that when one writes "Kaytataj" on the first and last folio of the book, one can be sure that worms will not attack it."[7]
  • Along with rats, cockroaches are frequently seen infesting various locations in Steve Purcell's comic book series Sam & Max, and one storyline features a race of gigantic cockroaches living on the moon.
  • Archy is a sympathetic cockroach in an historic series of newspaper columns by Don Marquis.
  • Revolt of the Cockroach People, an autobiographical novel by Oscar Zeta Acosta, cockroaches are used as a metaphor for oppressed and downtrodden minorities in US society in the 1960s and 1970s, particularly Mexican-Americans. There are several references to the folk song La Cucaracha throughout the novel.
  • In Vertigo comics' The Exterminators the main villain is a breed of cockroaches named Mayan Hissers, being responsible for "destroying" Mayan civilization.
  • Milquetoast the Cockroach was a character in the comic strips Bloom County and Outland by Berkeley Breathed.
  • In the young adult fiction series Gregor the Overlander by Suzanne Collins there are giant cockroaches beneath the Earth that are shy and emotional and help Gregor on his Quest. They are perceived by the other people under the Earth (Underlanders) as slow, weak, and cowardly things, but prove to be loyal to their allies and wiser than they appear.
  • In the comic series Badger there is a villain known as the Roach Wrangler, who holds supernatural control over an army of cockroaches.
  • In the manga series Terra Formars giant mutated humanoid cockroaches with incredible physical strength are the main antagonists.
  • The second in the Harry Hole crime novel series by Norwegian writer Jo Nesbø is entitled Cockroaches, with cockroaches used here as a metaphor for the murky Thai underworld into which the protagonist must plunge.
  • Naked Lunch — the main character, William Lee's "case worker" appears to him in the form of large cockroach that speaks through a hole in its abdomen. Later, this cockroach appears again as a hybrid of a cockroach/typewriter that has a keypad on its face. The case worker reveals his name as "Clark Nova", which also happens to be the name of Lee's typewriter model.
  • In the independent 1980s comic book series Domino Chance, both the title character and his sidekick Arnie are space-faring anthropomorphic cockroaches.
  • In Clarice Lispector’s 1968 novel The Passion According to G.H., a woman (G.H.) experiences an encounter with a cockroach that changes her perception of herself as a human being.[8]

In video games

  • In Bad Mojo, which is subtitled "The Roach Game" and loosely based on Franz Kafka's The Metamorphosis, the player takes on the role of a person turned into a cockroach. Other cockroaches provide the player with clues throughout the game.
  • Fallout 3, Fallout: New Vegas, Fallout 4, and Fallout 76 have a mutant form of the American cockroach called the Radroach. It is about the size of the house cat and is hostile towards the player if encountered.
  • In the Silent Hill series of games, monsters resembling cockroaches are featured in some enclosed spaces.
  • Cockroaches may be combined with other creatures in Impossible Creatures. Half-cockroaches can be used to spread the plague or defile an area of land, spreading disease to enemy creatures that cross the defiled land.
  • Half-Life allows the main character to crush cockroaches.
  • The character Sal in Sam & Max: The Devil's Playhouse is an anthropomorphic human size cockroach. Smaller cockroaches also appear in the series.
  • In the real-time strategy game StarCraft II: Wings of Liberty and its expansions, Zerg forces feature a unit known as the Roach, although taxonomically this creature has no relation to actual cockroaches.
  • In Call of Duty: Modern Warfare 2, one of the main protagonists, Gary Sanderson is nicknamed 'Roach'.
  • In every game in the Animal Crossing series, cockroaches can appear as household pests if the player hasn't entered their house for a while. The roaches will increase in number the longer the player leaves their house unattended (sometimes hiding under furniture), and can be crushed. In Animal Crossing and Animal Crossing: Wild World, cockroaches can be caught, donated to the Museum, and sold for 5 Bells (the game's form of currency), and in Animal Crossing: City Folk and Animal Crossing: New Leaf, a congratulatory message is played after clearing a room of cockroaches.
  • In Resident Evil 5, the Reaper is a Biological Organic Weapon formed by cockroaches mutated by Uroboros virus. They have sharp legs which can pierce their prey as well as high agility.
  • In Pokémon Sun and Moon, there's a cockroach-themed Pokémon called Pheromosa.

In music

Use as nickname

  • Boxing coach Freddie Roach was nicknamed La Cucaracha (The Cockroach) when he was still competing as a fighter.
  • Former England cricket captain-turned-media cricket analyst and commentator Michael Atherton was nicknamed as 'The Cockroach' by the former Australian cricket captain Steve Waugh because he was extremely difficult to stamp out.[9]
  • On the television series The Cosby Show the Huxtables' son Theo has a best friend nicknamed "Cockroach".
  • It is also the colloquial term for a resident of New South Wales and their Rugby League team in the State of Origin.
  • During the 2019 Hong Kong protest, members of the Hong Kong Police Force have called the protestors "cockroach-like rioters"[10][11], describing the protestors as non-human, an act that activists and protestors consider to be hate speech.[12]

References

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Cockroach

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This article is about the insect. For other uses, see Cockroach (disambiguation).
Cockroach
Temporal range: 145–0 Ma
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Cretaceous–recent
Snodgrass common household roaches.png
Common household cockroaches
A) German cockroach
B) American cockroach
C) Australian cockroach
D&E) Oriental cockroach (♀ & ♂)
Scientific classification
Kingdom:
Phylum:
Class:
Superorder:
Order:
Families

Blaberidae
Blattidae
Corydiidae
Cryptocercidae
Ectobiidae
Lamproblattidae
Nocticolidae
Tryonicidae

Cockroaches are insects of the order Blattodea, which also includes termites. About 30 cockroach species out of 4,600 are associated with human habitats. About four species are well known as pests.

The cockroaches are an ancient group, dating back at least as far as the Carboniferous period, some 320 million years ago. Those early ancestors however lacked the internal ovipositors of modern roaches. Cockroaches are somewhat generalized insects without special adaptations like the sucking mouthparts of aphids and other true bugs; they have chewing mouthparts and are likely among the most primitive of living neopteran insects. They are common and hardy insects, and can tolerate a wide range of environments from Arctic cold to tropical heat. Tropical cockroaches are often much bigger than temperate species, and, contrary to popular belief, extinct cockroach relatives and 'roachoids' such as the Carboniferous Archimylacris and the Permian Apthoroblattina were not as large as the biggest modern species.

Some species, such as the gregarious German cockroach, have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition. Cockroaches have appeared in human culture since classical antiquity. They are popularly depicted as dirty pests, though the great majority of species are inoffensive and live in a wide range of habitats around the world.

Taxonomy and evolution

220px-Baltic_amber_inclusions_-_Cockroac
 
A 40- to 50-million-year-old cockroach in Baltic amber (Eocene)

Cockroaches are members of the order Blattodea, which includes the termites, a group of insects once thought to be separate from cockroaches. Currently, 4,600 species and over 460 genera are described worldwide.[1][2] The name "cockroach" comes from the Spanish word for cockroach, cucaracha, transformed by 1620s English folk etymology into "cock" and "roach".[3] The scientific name derives from the Latin blatta, "an insect that shuns the light", which in classical Latin was applied to not only cockroaches, but also mantids.[4][5]

Historically, the name Blattaria was used largely interchangeably with the name Blattodea, but whilst the former name was used to refer to 'true' cockroaches exclusively, the latter also includes the termites. The current catalogue of world cockroach species uses the name Blattodea for the group.[1] Another name, Blattoptera, is also sometimes used.[6] The earliest cockroach-like fossils ("blattopterans" or "roachids") are from the Carboniferous period 320 million years ago, as are fossil roachoid nymphs.[7][8][9]

Since the 19th century, scientists believed that cockroaches were an ancient group of insects that had a Devonian origin, according to one hypothesis.[10] Fossil roachoids that lived during that time differ from modern cockroaches in having long external ovipositors and are the ancestors of mantises, as well as modern blattodeans. As the body, hind wings and mouthparts are not preserved in fossils frequently, the relationship of these roachoids and modern cockroaches remains disputed. The first fossils of modern cockroaches with internal ovipositors appeared in the early Cretaceous. A recent phylogenetic analysis suggests that cockroaches originated at least in the Jurassic.[10]

The evolutionary relationships of the Blattodea (cockroaches and termites) shown in the cladogram are based on Eggleton, Beccaloni & Inward (2007).[11] The cockroach families Lamproblattidae and Tryonicidae are not shown but are placed within the superfamily Blattoidea. The cockroach families Corydiidae and Ectobiidae were previously known as the Polyphagidae and Blattellidae.[12]

Dictyoptera
Blattodea
Blattoidea
Termitoidea (Termites)

Termitidae

Rhinotermitidae

Kalotermitidae

Termopsidae

Hodotermitidae

Mastotermitidae

Cryptocercoidae

Cryptocercidae (brown-hooded cockroaches)

Blattidae (Oriental, American and other cockroaches)

Blaberoidea

Blaberidae (Giant cockroaches)

Ectobiidae (part)

Ectobiidae (part)

Corydioidea

Corydiidae (Sand cockroaches, etc)

Nocticolidae (Cave cockroaches, etc)

Mantodea (Mantises)

Termites were previously regarded as a separate order Isoptera to cockroaches. However, recent genetic evidence strongly suggests that they evolved directly from 'true' cockroaches, and many authors now place them as an "epifamily" of Blattodea.[11] This evidence supported a hypothesis suggested in 1934 that termites are closely related to the wood-eating cockroaches (genus Cryptocercus). This hypothesis was originally based on similarity of the symbiotic gut flagellates in termites regarded as living fossils and wood-eating cockroaches.[13] Additional evidence emerged when F. A. McKittrick (1965) noted similar morphological characteristics between some termites and cockroach nymphs.[14] The similarities among these cockroaches and termites have led some scientists to reclassify termites as a single family, the Termitidae, within the order Blattodea.[11][15] Other scientists have taken a more conservative approach, proposing to retain the termites as the Termitoidea, an epifamily within the order. Such measure preserves the classification of termites at family level and below.[16]

Description

170px-Domino_cockroach_Therea_petiverian
 
Domino cockroach Therea petiveriana, normally found in India

Most species of cockroach are about the size of a thumbnail, but several species are bigger. The world's heaviest cockroach is the Australian giant burrowing cockroach Macropanesthia rhinoceros, which can reach 9 cm (3.5 in) in length and weigh more than 30 g (1.1 oz).[17] Comparable in size is the Central American giant cockroach Blaberus giganteus.[18] The longest cockroach species is Megaloblatta longipennis, which can reach 97 mm (3.8 in) in length and 45 mm (1.8 in) across.[19] A Central and South American species, Megaloblatta blaberoides, has the largest wingspan of up to 185 mm (7.3 in).[20]

170px-Cockroach_head.jpg
 

Cockroaches are generalized insects, with few special adaptations, and may be among the most primitive living neopteran insects. They have a relatively small head and a broad, flattened body, and most species are reddish-brown to dark brown. They have large compound eyes, two ocelli, and long, flexible antennae. The mouthparts are on the underside of the head and include generalized chewing mandibles, salivary glands and various touch and taste receptors.[21]

The body is divided into a thorax of three segments and a ten-segmented abdomen. The external surface has a tough exoskeleton which contains calcium carbonate and protects the inner organs and provides attachment to muscles. It is coated with wax to repel water. The wings are attached to the second and third thoracic segments. The tegmina, or first pair of wings, are tough and protective, lying as a shield on top of the membranous hind wings, which are used in flight. All four wings have branching longitudinal veins, and multiple cross-veins.[22]

The three pairs of legs are sturdy, with large coxae and five claws each.[22] They are attached to each of the three thoracic segments. The front legs are the shortest and the hind legs the longest, providing the main propulsive power when the insect runs.[21] The spines on the legs were earlier considered to be sensory, but observations of the insect's gait on sand and wire meshes have demonstrated that they help in locomotion on difficult terrain. The structures have been used as inspiration for robotic legs.[23][24]

The abdomen has ten segments, each with a pair of spiracles for respiration. Segment ten bears a pair of cerci, a pair of anal styles, the anus and the external genitalia. Males have an aedeagus through which they secrete sperm during copulation and females have spermathecae for storing sperm and an ovipositor through which the ootheca is laid.[21]

Distribution and habitat

Cockroaches are abundant throughout the world and live in a wide range of environments, especially in the tropics and subtropics.[25] Cockroaches can withstand extremely cold temperatures, allowing them to live in the Arctic. Some species are capable of surviving temperatures of −188 °F (−122 °C) by manufacturing an antifreeze made out of glycerol.[26] In North America, 50 species separated into five families are found throughout the continent.[25] 450 species are found in Australia.[27] Only about four widespread species are commonly regarded as pests.[28][29]

Cockroaches occupy a wide range of habitats. Many live in leaf litter, among the stems of matted vegetation, in rotting wood, in holes in stumps, in cavities under bark, under log piles and among debris. Some live in arid regions and have developed mechanisms to survive without access to water sources. Others are aquatic, living near the surface of water bodies, including bromeliad phytotelmata, and diving to forage for food. Most of these respire by piercing the water surface with the tip of the abdomen which acts as a snorkel, but some carry a bubble of air under their thoracic shield when they submerge. Others live in the forest canopy where they may be one of the main types of invertebrate present. Here they may hide during the day in crevices, among dead leaves, in bird and insect nests or among epiphytes, emerging at night to feed.[30]

Behavior

170px-Ecdysis.jpg
 
A cockroach soon after ecdysis

Cockroaches are social insects; a large number of species are either gregarious or inclined to aggregate, and a slightly smaller number exhibit parental care.[31] It used to be thought that cockroaches aggregated because they were reacting to environmental cues, but it is now believed that pheromones are involved in these behaviors. Some species secrete these in their feces with gut microbial symbionts being involved, while others use glands located on their mandibles. Pheromones produced by the cuticle may enable cockroaches to distinguish between different populations of cockroach by odor. The behaviors involved have been studied in only a few species, but German cockroaches leave fecal trails with an odor gradient.[31] Other cockroaches follow such trails to discover sources of food and water, and where other cockroaches are hiding. Thus, cockroaches have emergent behavior, in which group or swarm behavior emerges from a simple set of individual interactions.[32]

Daily rhythms may also be regulated by a complex set of hormonal controls of which only a small subset have been understood. In 2005, the role of one of these proteins, pigment dispersing factor (PDF), was isolated and found to be a key mediator in the circadian rhythms of the cockroach.[33]

Pest species adapt readily to a variety of environments, but prefer warm conditions found within buildings. Many tropical species prefer even warmer environments. Cockroaches are mainly nocturnal[34] and run away when exposed to light. An exception to this is the Asian cockroach, which flies mostly at night but is attracted to brightly lit surfaces and pale colors.[35]

Collective decision-making

Gregarious cockroaches display collective decision-making when choosing food sources. When a sufficient number of individuals (a "quorum") exploits a food source, this signals to newcomer cockroaches that they should stay there longer rather than leave for elsewhere.[36] Other mathematical models have been developed to explain aggregation dynamics and conspecific recognition.[37][38]

Cooperation and competition are balanced in cockroach group decision-making behavior.[32]

Cockroaches appear to use just two pieces of information to decide where to go, namely how dark it is and how many other cockroaches there are. A study used specially-scented roach-sized robots that appear to the roaches as real to demonstrate that once there are enough insects in a place to form a critical mass, the roaches accepted the collective decision on where to hide, even if this was an unusually lit place.[39]

Social behavior

When reared in isolation, German cockroaches show behavior that is different from behavior when reared in a group. In one study, isolated cockroaches were less likely to leave their shelters and explore, spent less time eating, interacted less with conspecifics when exposed to them, and took longer to recognize receptive females. Because these changes occurred in many contexts, the authors suggested them as constituting a behavioral syndrome. These effects might have been due either to reduced metabolic and developmental rates in isolated individuals or the fact that the isolated individuals hadn't had a training period to learn about what others were like via their antennae.[40]

Individual American cockroaches appear to have consistently different "personalities" regarding how they seek shelter. In addition, group personality is not simply the sum of individual choices, but reflects conformity and collective decision-making.[41][42]

The gregarious German and American cockroaches have elaborate social structure, chemical signalling, and "social herd" characteristics. Lihoreau and his fellow researchers stated:[32]

The social biology of domiciliary cockroaches ... can be characterized by a common shelter, overlapping generations, non-closure of groups, equal reproductive potential of group members, an absence of task specialization, high levels of social dependence, central place foraging, social information transfer, kin recognition, and a meta-population structure.[32]

Sounds

Some species make a hissing noise while other cockroaches make a chirping noise. The Madagascar hissing cockroach produces its sound through the modified spiracles on the fourth abdominal segment. Several different hisses are produced, including disturbance sounds, produced by adults and larger nymphs; and aggressive, courtship and copulatory sounds produced by adult males.[43]Henschoutedenia epilamproides has a stridulatory organ between its thorax and abdomen, but the purpose of the sound produced is unclear.[44]

Several Australian species practice acoustic and vibration behavior as an aspect of courtship. They have been observed producing hisses and whistles from air forced through the spiracles. Furthermore, in the presence of a potential mate, some cockroaches tap the substrate in a rhythmic, repetitive manner. Acoustic signals may be of greater prevalence amongst perching species, particularly those that live on low vegetation in Australia's tropics.[45]

Biology

Digestive tract

Cockroaches are generally omnivorous; the American cockroach (Periplaneta americana), for example, feeds on a great variety of foodstuffs including bread, fruit, leather, starch in book bindings, paper, glue, skin flakes, hair, dead insects and soiled clothing.[46] Many species of cockroach harbor in their gut symbiotic protozoans and bacteria which are able to digest cellulose. In many species, these symbionts may be essential if the insect is to utilize cellulose; however, some species secrete cellulase in their saliva, and the wood-eating cockroach, Panesthia cribrata, is able to survive indefinitely on a diet of crystallized cellulose while being free of micro-organisms.[47]

The similarity of these symbionts in the genus Cryptocercus to those in termites are such that these cockroaches have been suggested to be more closely related to termites than to other cockroaches,[48] and current research strongly supports this hypothesis about their relationships.[49] All species studied so far carry the obligate mutualistic endosymbiont bacterium Blattabacterium, with the exception of Nocticola australiensise, an Australian cave-dwelling species without eyes, pigment or wings, which recent genetic studies indicate is a very primitive cockroach.[50][51] It had previously been thought that all five families of cockroach were descended from a common ancestor that was infected with B. cuenoti. It may be that N. australiensise subsequently lost its symbionts, or alternatively this hypothesis will need to be re-examined.[51]

Tracheae and breathing

Like other insects, cockroaches breathe through a system of tubes called tracheae which are attached to openings called spiracles on all body segments. When the carbon dioxide level in the insect rises high enough, valves on the spiracles open and carbon dioxide diffuses out and oxygen diffuses in. The tracheal system branches repeatedly, the finest tracheoles bringing air directly to each cell, allowing gaseous exchange to take place.[52]

While cockroaches do not have lungs as do vertebrates, and can continue to respire if their heads are removed, in some very large species, the body musculature may contract rhythmically to forcibly move air in and out of the spiracles; this may be considered a form of breathing.[52]

Reproduction

Cockroaches use pheromones to attract mates, and the males practice courtship rituals, such as posturing and stridulation. Like many insects, cockroaches mate facing away from each other with their genitalia in contact, and copulation can be prolonged. A few species are known to be parthenogenetic, reproducing without the need for males.[22]

Female cockroaches are sometimes seen carrying egg cases on the end of their abdomens; the German cockroach holds about 30 to 40 long, thin eggs in a case called an ootheca. She drops the capsule prior to hatching, though live births do occur in rare instances. The egg capsule may take more than five hours to lay and is initially bright white in color. The eggs are hatched from the combined pressure of the hatchlings gulping air. The hatchlings are initially bright white nymphs and continue inflating themselves with air, becoming harder and darker within about four hours. Their transient white stage while hatching and later while molting has led to claims of albino cockroaches.[22] Development from eggs to adults takes three to four months. Cockroaches live up to a year, and the female may produce up to eight egg cases in a lifetime; in favorable conditions, she can produce 300 to 400 offspring. Other species of cockroaches, however, can produce far more eggs; in some cases a female needs to be impregnated only once to be able to lay eggs for the rest of her life.[22]

The female usually attaches the egg case to a substrate, inserts it into a suitably protective crevice, or carries it about until just before the eggs hatch. Some species, however, are ovoviviparous, keeping the eggs inside their body, with or without an egg case, until they hatch. At least one genus, Diploptera, is fully viviparous.[22]

Cockroaches have incomplete metamorphosis, meaning that the nymphs are generally similar to the adults, except for undeveloped wings and genitalia. Development is generally slow, and may take a few months to over a year. The adults are also long-lived, and have survived for as much as four years in the laboratory.[22]

Hardiness

Cockroaches are among the hardiest insects. Some species are capable of remaining active for a month without food and are able to survive on limited resources, such as the glue from the back of postage stamps.[53] Some can go without air for 45 minutes. Japanese cockroach (Periplaneta japonica) nymphs, which hibernate in cold winters, survived twelve hours at −5 °C to −8 °C in laboratory experiments.[54]

Experiments on decapitated specimens of several species of cockroach found a variety of behavioral functionality remained, including shock avoidance and escape behavior, although many insects other than cockroaches are also able to survive decapitation, and popular claims of the longevity of headless cockroaches do not appear to be based on published research.[55][56] The severed head is able to survive and wave its antennae for several hours, or longer when refrigerated and given nutrients.[56]

It is popularly suggested that cockroaches will "inherit the earth" if humanity destroys itself in a nuclear war. Cockroaches do indeed have a much higher radiation resistance than vertebrates, with the lethal dose perhaps six to 15 times that for humans. However, they are not exceptionally radiation-resistant compared to other insects, such as the fruit fly.[57]

The cockroach's ability to withstand radiation better than human beings can be explained through the cell cycle. Cells are most vulnerable to the effects of radiation when they are dividing. A cockroach's cells divide only once each time it molts, which is weekly at most in a juvenile roach. Since not all cockroaches would be molting at the same time, many would be unaffected by an acute burst of radiation, although lingering radioactive fallout would still be harmful.[52]

Relationship with humans

220px-%22Periplaneta_americana%22_connec
 
Cockroaches in research: Periplaneta americana in an electrophysiology experiment

In research and education

Because of their ease of rearing and resilience, cockroaches have been used as insect models in the laboratory, particularly in the fields of neurobiology, reproductive physiology and social behavior.[31] The cockroach is a convenient insect to study as it is large and simple to raise in a laboratory environment. This makes it suitable both for research and for school and undergraduate biology studies. It can be used in experiments on topics such as learning, sexual pheromones, spatial orientation, aggression, activity rhythms and the biological clock, and behavioral ecology.[58] Research conducted in 2014 suggests that humans fear cockroaches the most, even more than mosquitoes, due to an evolutionary aversion.[59]

As pests

The Blattodea include some thirty species of cockroaches associated with humans; these species are atypical of the thousands of species in the order.[60] They feed on human and pet food and can leave an offensive odor.[61] They can passively transport pathogenic microbes on their body surfaces, particularly in environments such as hospitals.[62][63] Cockroaches are linked with allergic reactions in humans.[64][65] One of the proteins that trigger allergic reactions is tropomyosin.[66] These allergens are also linked with asthma.[67] About 60% of asthma patients in Chicago are also sensitive to cockroach allergens. Studies similar to this have been done globally and all the results are similar. Cockroaches can live for a few days up to a month without food, so just because no cockroaches are visible in a home does not mean they are not there. Approximately 20-48% of homes with no visible sign of cockroaches have detectable cockroach allergens in dust.[68]

Cockroaches can burrow into human ears, causing pain and hearing loss.[69][70] They may be removed with forceps, possibly after first drowning with olive oil.[71][72][73]

Control

Many remedies have been tried in the search for control of the major pest species of cockroaches, which are resilient and fast-breeding. Household chemicals like sodium bicarbonate (baking soda) have been suggested, without evidence for their effectiveness.[74] Garden herbs including bay, catnip, mint, cucumber, and garlic have been proposed as repellents.[75] Poisoned bait containing hydramethylnon or fipronil, and boric acid powder is effective on adults.[76] Baits with egg killers are also quite effective at reducing the cockroach population. Alternatively, insecticides containing deltamethrin or pyrethrin are very effective.[76] In Singapore and Malaysia, taxi drivers use pandan leaves to repel cockroaches in their vehicles.[77]

Few parasites and predators are effective for biological control of cockroaches. Parasitoidal wasps such as Ampulex wasps sting nerve ganglia in the cockroach's thorax, temporarily paralyzing the victim, allowing the wasp to deliver an incapacitating sting into the cockroach's brain. The wasp clips the antennae with its mandibles and drinks some hemolymph before dragging the prey to a burrow, where an egg (rarely two) is laid on it.[78] The wasp larva feeds on the subdued living cockroach.[79][80] Another wasp which is considered a promising candidate for biological control is the ensign wasp Evania appendigaster which attacks cockroach oothecae to lay a single egg inside.[81][82] Ongoing research is still developing technologies allowing for mass-rearing these wasps for application releases.[83][84]

Cockroaches can be trapped in a deep, smooth-walled jar baited with food inside, placed so that cockroaches can reach the opening, for example with a ramp of card or twigs on the outside. An inch or so of water or stale beer (by itself a cockroach attractant) in the jar can be used to drown any insects thus captured. The method works well with the American cockroach, but less so with the German cockroach.[85]

A study conducted by scientists at Purdue University concluded that the most common cockroaches in the US, Australia and Europe were able to develop a “cross resistance” to multiple types of pesticide. This contradicted previous understanding that the animals can develop resistance against one pesticide at a time.[86] The scientists suggested that cockroaches will no longer be easily controlled using a diverse spectrum of chemical pesticides and that a mix of other means, such as traps and better sanitation, will need to be employed.[87]

As food

Although considered disgusting in Western culture, cockroaches are eaten in many places around the world.[88][89] Whereas household pest cockroaches may carry bacteria and viruses, cockroaches bred under laboratory conditions can be used to prepare nutritious food.[90] In Mexico and Thailand, the heads and legs are removed, and the remainder may be boiled, sautéed, grilled, dried or diced.[88] In China, cockroaches have become popular as medicine and cockroach farming is rising with over 100 farms.[91] The cockroaches are fried twice in a wok of hot oil, which makes them crispy with soft innards that are like cottage cheese.[92][93] Fried cockroaches are ground and sold as pills for stomach, heart and liver diseases.[94] A cockroach recipe from Formosa (Taiwan) specifies salting and frying cockroaches after removing the head and entrails.[95]

In traditional and homeopathic medicine

In China, cockroaches are raised in large quantities for medicinal purposes.[96]

Two species of cockroach were used in homeopathic medicine in the 19th century.[97]

Conservation

While a small minority of cockroaches are associated with human habitats and viewed as repugnant by many people, a few species are of conservation concern. The Lord Howe Island wood-feeding cockroach (Panesthia lata) is listed as endangered by the New South Wales Scientific Committee, but the cockroach may be extinct on Lord Howe Island itself. The introduction of rats, the spread of Rhodes grass (Chloris gayana) and fires are possible reasons for their scarcity.[98] Two species are currently listed as endangered and critically endangered by the IUCN Red List, Delosia ornata and Nocticola gerlachi.[99][100] Both cockroaches have a restricted distribution and are threatened by habitat loss and rising sea levels. Only 600 Delosia ornata adults and 300 nymphs are known to exist, and these are threatened by a hotel development. No action has been taken to save the two cockroach species, but protecting their natural habitats may prevent their extinction. In the former Soviet Union, cockroach populations have been declining at an alarming rate; this may be exaggerated, or the phenomenon may be temporary or cyclic.[101] One species of roach, Simandoa conserfariam, is considered extinct in the wild.

Cultural depictions

220px-Roachies.JPG
 

Cockroaches were known and considered repellent but useful in medicines in Classical times. An insect named in Greek "σίλφη" (silphe) has been identified with the cockroach. It is mentioned by Aristotle, saying that it sheds its skin; it is described as foul-smelling in Aristophanes' play Peace; Euenus called it a pest of book collections, being "page-eating, destructive, black-bodied" in his Analect. Virgil named the cockroach "Lucifuga" ("one that avoids light"). Pliny the Elder recorded the use of "Blatta" in various medicines; he describes the insect as disgusting, and as seeking out dark corners to avoid the light.[102][103]Dioscorides recorded the use of the "Silphe", ground up with oil, as a remedy for earache.[103]

Lafcadio Hearn (1850–1904) asserted that "For tetanus cockroach tea is given. I do not know how many cockroaches go to make up the cup; but I find that faith in this remedy is strong among many of the American population of New Orleans. A poultice of boiled cockroaches is placed over the wound." He adds that cockroaches are eaten, fried with garlic, for indigestion.[104]

Several cockroach species, such as Blaptica dubia, are raised as food for insectivorous pets.[105] A few cockroach species are raised as pets, most commonly the giant Madagascar hissing cockroach, Gromphadorhina portentosa.[106] Whilst the hissing cockroaches may be the most commonly kept species, there are many species that are kept by cockroach enthusiasts; there is even a specialist society: the Blattodea Culture Group (BCG), which was a thriving organisation for about 15 years although now appears to be dormant.[107] The BCG provided a source of literature for people interested in rearing cockroaches which was otherwise limited to either scientific papers, or general insect books, or books covering a variety of exotic pets; in the absence of an inclusive book one member published Introduction to Rearing Cockroaches which still appears to be the only book dedicated to rearing cockroaches.[108]

Cockroaches have been used for space tests. A cockroach given the name Nadezhda was sent into space by Russian scientists as part of a Foton-M mission, during which she mated, and later became the first terrestrial animal to produce offspring that had been conceived in space.[109]

Because of their long association with humans, cockroaches are frequently referred to in popular culture. In Western culture, cockroaches are often depicted as dirty pests.[110][111] In a 1750–1752 journal, Peter Osbeck noted that cockroaches were frequently seen and found their way to the bakeries, after the sailing ship Gothenburg ran aground and was destroyed by rocks.[112]

Donald Harington's satirical novel The Cockroaches of Stay More (Harcourt, 1989) imagines a community of "roosterroaches" in a mythical Ozark town where the insects are named after their human counterparts. Madonna has famously quoted, "I am a survivor. I am like a cockroach, you just can't get rid of me."[113] An urban legend maintains that cockroaches are immortal.[114]

References

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