omniomni/omni-engineering huggingface dataset:
Pot metal. Pot metal (or monkey metal) is an alloy of low-melting point metals that manufacturers use to make fast, inexpensive castings. The term "pot metal" came about because of automobile factories' practice in the early 20th century of gathering up non-ferrous metal scraps from the manufacturing processes and melting them in one pot to form into cast products. Small amounts of iron often made it into the castings but never in significant quantity because too much iron would raise the melting point too high for simple casting operations. 

In stained glass, "pot metal" or pot metal glass refers to glass coloured with metal oxides while it is molten (in a pot), as opposed to other methods of colouring glass in sheet form.

Metallurgy
There is no metallurgical standard for pot metal. Common metals in pot metal include zinc, lead, copper, tin, magnesium, aluminum, iron, and cadmium. The primary advantage of pot metal is that it is quick and easy to cast. Because of its low melting temperature, it requires no sophisticated foundry equipment or specialized molds. Manufacturers sometimes use it to experiment with molds and ideas (e.g., prototypes) before casting final products in a higher quality alloy. 

Depending on the exact metals "thrown into the pot", pot metal can become unstable over time, as it has a tendency to bend, distort, crack, shatter, and pit with age. The low boiling point of zinc and fast cooling of newly cast parts often trap air bubbles within the cast part, weakening it. Many components common in pot metal are susceptible to corrosion from airborne acids and other contaminants, and internal corrosion of the metal often causes decorative plating to flake off. Pot metal is not easily glued, soldered, or welded.

In the late nineteenth century, pot metal referred specifically to a copper alloy that was primarily alloyed with lead. Mixtures of 67% copper with 29% lead and 4% antimony and another one of 80% copper with 20% lead were common formulations.

The primary component of pot metal is zinc, but often the caster adds other metals to the mix to strengthen the cast part, improve flow of the molten metal, or to reduce cost. With a low melting point of 420 °C (786 °F), zinc is often alloyed with other metals including lead, tin, aluminium, and copper.

Uses

Pot metal is generally used for parts that are not subject to high stresses or torque.  Items created from pot metal include toys, furniture fittings, tool parts, electronics components, automotive parts, inexpensive jewelry and improvised weaponry.. Pot metal was commonly used to manufacture gramophone parts in the late 1920s and 1930s, with notable examples being the back covers on some HMV no.4 soundboxes and HMV no.5 soundboxes.  It was also used to make loudspeaker transducers used with early radio horn speakers before cone speakers were developed.  It is also used in inexpensive electric guitars and other budget-priced musical instruments.

See also
 Babbitt (alloy)
 Pewter
 White metal
 Zamak
 Zinc aluminium
 Zinc pest

References

Copper alloys
Zinc alloys
Collaborative human interpreter. The collaborative human interpreter (CHI) is a proposed software interface for human-based computation (first proposed as a programming language on the blog Google Blogoscoped, but implementable via an API in virtually any programming language) specially designed for collecting 
and making use of human intelligence in a computer program.
One typical usage is implementing impossible-to-automate functions.

For example, it is currently difficult for a computer to differentiate between images of men, women and non-humans. However, this is easy for people. A programmer using CHI could write a code fragment along these lines:

 enum GenderCode {
  MALE, FEMALE, NOT_A_HUMAN 
 }
 Photo photo = loadPhoto(file)
 GenderCode result = checkGender(photo)

Code for the function checkGender(Photo p) can currently only approximate a result, but the task can easily be solved by a person. When the function checkGender() is called, the system will send a request to someone, and the person who received the request will process the task and input the result. If the person (task processor) inputs value MALE, you'll get the value in your variable result, in your program. This querying process can be highly automated.

Deployment 

On November 6, 2005, Amazon.com launched 
CHI as its business platform in the Amazon Mechanical Turk. It's the first business application using CHI.

Origins 
CHI is originally mentioned in  Philipp Lenssen's  blog.

References

External links 

 "Amazon looks to solve problems that stump computers", ZDnet, Nov 10, 2005 

Domain-specific programming languages
Human-based computation
Boxcab. A boxcab, in railroad terminology, is a term for an electric locomotive in which the machinery and crew areas were enclosed in a box-like superstructure. Deriving from "boxcar", the term mainly occurs in North America. The term has rarely been applied to diesel locomotives. It was also applied in Australia to Victorian Railways' "E" class second series electric locomotives.

Boxcabs could also be diesel locomotives such as the case of the many AGEIR (Alco, General Electric, Ingersoll-Rand) boxcabs, but the overwhelming majority of them were electric. 

Most North American boxcabs were built a few years before and after 1930, the most prominent builders being Baldwin and Westinghouse, GE and Alco.

Design
Locomotives had either a box-like body of equal height along their whole length including the cabs, the boxcab; or else the cabs were inset from the ends and a lower nose or 'hood' section protruded beyond.  

Boxcabs did not have heavily styled ends or a superstructure consisting of multiple structures, although the prototype diesel/oil-electric, GE no. 8835, had one end prominently rounded – attributed to its trolley (tram) car ancestry – and the second and following 100-ton ALCO boxcabs had semi-cylindrical ends.

See also

 Box motor
 GE three-power boxcab
 GE 57-ton gas–electric boxcab

References

Locomotive body styles
List of broadsides of major World War II ships. This list of broadsides of major World War II ships ranks the total weight of projectiles that can be delivered in single broadsides by major vessels in service during World War II.  Listed are the broadsides in pounds and kilograms (for a single main battery salvo), as well as the range to which it can be fired in yards and kilometres and the maximum rate of fire in salvos per minute.

Items are listed in order of broadside weight.

Broadsides
Broadsides
Cray MTA-2. The Cray MTA-2 is a shared-memory MIMD computer marketed by Cray Inc. It is an unusual design based on the Tera computer designed by Tera Computer Company. The original Tera computer (also known as the MTA) turned out to be nearly unmanufacturable due to its aggressive packaging and circuit technology. The MTA-2 was an attempt to correct these problems while maintaining essentially the same processor architecture respun in one silicon ASIC, down from some 26 gallium arsenide ASICs in the original MTA; and while regressing the network design from a 4-D torus topology to a less efficient but more scalable Cayley graph topology. The name Cray was added to the second version after Tera Computer Company bought the remains of the Cray Research division of Silicon Graphics in 2000 and renamed itself Cray Inc.

The MTA-2 was not a commercial success, with only one moderately-sized 40-processor system ("Boomer") being sold to the United States Naval Research Laboratory in 2002, and one 4-processor system sold to the Electronic Navigation Research Institute (ENRI) in Japan.

The MTA computers pioneered several technologies, presumably to be used in future Cray Inc. products:

 A simple, whole-machine-oriented programming model.
 Hardware-based multithreading.
 Low-overhead thread synchronization.

See also
 Cray MTA
 Heterogeneous Element Processor

References

External links
Utrecht University HPCG - Cray MTA-2 page

Mta-2
Supercomputers
Picene. Picene is a hydrocarbon found in the pitchy residue obtained in the distillation of peat tar and of petroleum. This is distilled to dryness and the distillate repeatedly recrystallized from cymene. It may be synthetically prepared by the action of anhydrous aluminium chloride on a mixture of naphthalene and 1,2-dibromoethane, or by distilling a-dinaphthostilbene. It crystallizes in large colorless plates which possess a blue fluorescence. It is soluble in concentrated sulfuric acid with a green color. Chromic acid in glacial acetic acid solution oxidizes it to picene-quinone, picene-quinone carboxylic acid, and finally to phthalic acid.

When intercalated with potassium or rubidium and cooled to below 18 K, picene has been reported to exhibit superconductive properties. However, due to the apparent inability to reproduce this work, the superconducting nature of doped picene has been met with heavy scepticism.

Picene is also a major constituent of the hydrocarbon mineral idrialite.

See also
 Olympicene, which has the same number of rings linked in a different way

References

Polycyclic aromatic hydrocarbons
Steve Ciarcia. Steve Ciarcia is an American embedded control systems engineer. He became popular through his Ciarcia's Circuit Cellar column in BYTE magazine, and later through the Circuit Cellar magazine that he published. He is also the author of Build Your Own Z80 Computer, edited in 1981 and Take My Computer...Please!, published in 1978. He has also compiled seven volumes of his hardware project articles that appeared in BYTE magazine.

In 1982 and 1983, he published a series of articles on building the MPX-16, a 16-bit single-board computer that was hardware-compatible with the IBM PC.

In December 2009, Steve Ciarcia announced that for the American market a strategic cooperation would be entered between Elektor and his Circuit Cellar magazine.  In November 2012, Steve Ciarcia announced that he was quitting Circuit Cellar and Elektor would take it over.

In October 2014, Ciarcia purchased Circuit Cellar, audioXpress, Voice Coil, Loudspeaker Industry Sourcebook, and their respective websites, newsletters, and products from Netherlands-based Elektor International Media. The aforementioned magazines will continue to be published by Ciarcia's US-based team.

In July 2016, Steve Ciarcia sold the company to long time employee KC Prescott operating under the company name KCK Media Corp.

References

External links
 Circuit Cellar magazine
 Index on Steve Ciarcia's articles in BYTE

American magazine editors
American technology writers
Control theorists
Living people
Year of birth missing (living people)
Propiolic acid. Propiolic acid is the organic compound with the formula HC2CO2H.  It is the simplest acetylenic carboxylic acid.  It is a colourless liquid that crystallises to give silky crystals.  Near its boiling point, it decomposes.

It is soluble in water and possesses an odor like that of acetic acid.

Preparation
It is prepared commercially by oxidizing propargyl alcohol at a lead electrode. It can also be prepared by decarboxylation of acetylenedicarboxylic acid.

Reactions and applications
Exposure to sunlight converts it into trimesic acid (benzene-1,3,5-tricarboxylic acid). It undergoes bromination to give dibromoacrylic acid.  With hydrogen chloride it forms chloroacrylic acid. Its ethyl ester condenses with hydrazine to form pyrazolone.

It forms a characteristic explosive solid upon treatment to its aqueous solution with ammoniacal silver nitrate.  An amorphous explosive precipitate forms with ammoniacal cuprous chloride.

Propiolates
Propiolates are esters or salts of propiolic acid.  Common examples include methyl propiolate and ethyl propiolate.

See also
 Propargyl
 Propargyl alcohol

References

Carboxylic acids
Alkyne derivatives
Durable water repellent. Durable water repellent, or DWR, is a coating added to fabrics at the factory to make them water-resistant (hydrophobic). Most factory-applied treatments are fluoropolymer based; these applications are quite thin and not always effective. Durable water repellents are commonly used in conjunction with waterproof breathable fabrics such as Gore-Tex to prevent the outer layer of fabric from becoming saturated with water. This saturation, called 'wetting out,' can reduce the garment's breathability (moisture transport through the breathable membrane) and let water through. As the DWR wears off over time, re-treatment is recommended when necessary.  Many spray-on and wash-in products for treatment of non-waterproof garments and re-treatment of proofed garments losing their water-repellency are available.

Methods for factory application of DWR treatments involve applying a solution of a chemical onto the surface of the fabric by spraying or dipping, or chemical vapor deposition (CVD). The advantages of CVD include reducing the use of environmentally harmful solvents; requiring less DWR; and an extremely thin waterproof layer that has less effect on the natural look and feel of the fabric.

Some researchers have suggested that the use of PFAS in water-repellent clothing is over-engineering, and comparable performance can be achieved using specific silicon- and hydrocarbon-based finishes.

Re-treating garments 

Certain types of fabrics need to be re-treated to maintain water-repellency, as fluoropolymers decompose over time when exposed to water and chemicals. Washing the garment with harsh detergents usually accelerates DWR loss; in addition, soaps often leave a residue which attracts water and dirt. On the other hand, rain water or salt water affects DWRs less significantly. Affected garments can be treated with a 'spray-on' or 'wash-in' treatment to improve water-repellency. In some cases heat treatment can reactivate the factory applied repellent finish and aid in the repelling of water, and other liquids such as oils. On the other hand, some DWR products do not require heat treatment to be activated, and sometimes DWR treatments can be revitalized simply by washing the fabric with a suitable cleaner.

Cravenette 
Cravenette was an old process to make cloths water-repellent. It was a performance finish that repelled water. Various U.S.-based suppliers, such as A. Murphy, W.G. Hitchcock, and H. Herrmann, were offering Cravenette-treated cloths in the early 20th century.

See also
 Finishing (textiles)
 Nikwax Analogy
 P2i
 Perfluorobutanesulfonic acid
 Perfluorooctanoic acid
 Scotchgard

References 

Technical fabrics
Textile chemistry
Textile treatments
Parallel optical interface. A parallel optical interface is a form of fiber-optic technology aimed primarily at communications and networking over relatively short distances (less than 300 meters), and at high bandwidths.

Parallel optic interfaces differ from traditional fiber-optic communication in that data is simultaneously transmitted and received over multiple fibers. Different methods exist for splitting the data over this high-bandwidth link. In the simplest form, the parallel optic link is a replacement for many serial-data communication links. In the more typical application, one byte of information is split up into bits and each bit is coded and sent across the individual fibers. Needless to say, there are many ways to perform this multiplexing provided the fundamental coding at the fiber level meets the channel requirement.

The main applications for parallel optical interfaces are found in telecommunications and supercomputers, also being introduced to consumer applications. It displaces copper backplanes that are commonly used for large switching equipment design.

There are two forms of commercially available products for parallel optic interfaces. The first is a twelve-channel system consisting of an optical transmitter and an optical receiver. The second is a four channel transceiver product that is capable of transmitting four channels and receiving four channels in one product.

Parallel optics is often the most cost-effective solution for getting 40 Gigabit per second transmission of data over distances exceeding 100 meters. 100GE Optical Transceiver comes with 100 Gigabit of data transmit. Data is delivered in both duplex and parallel mechanism with 100GE.

See also
 Fiber-optic cable
 Interconnect bottleneck
 Optical communication
 Thunderbolt (interface)

References

Fiber-optic communications
Harry Boot. Henry Albert Howard Boot (29 July 1917 – 8 February 1983) was an English physicist who with Sir John Randall and James Sayers developed the cavity magnetron, which was one of the keys to the Allied victory in the Second World War.

Biography

Henry Boot was born in Birmingham and attended King Edward's School, Birmingham and the University of Birmingham. While working on his PhD the war broke out.  His professor Mark Oliphant had seen the klystron at Stanford University but it produced insufficient power to be useful as a radar transmitter.  He assigned John Randall and Boot to the problem.  By late February 1940, they had invented the much more powerful cavity magnetron which was fitted in an experimental radar by May 1940.

James Sayers later refined the magnetron still further by strapping alternate cavities. As with many British inventions of this period, the magnetron was provided to the US for free when they entered World War II. Initially Boot and Randall were awarded £50 each for the magnetron for "improving the safety of life at sea", but in 1949 Boot, Randall and Sayers received a £36,000 prize for their work.

After a brief time at British Thomson-Houston, Rugby, in the latter years of the war, Boot returned to Birmingham as the Nuffield Research Fellow. After some work on nuclear physics, Boot returned to magnetrons and after the war built a cyclotron at Birmingham.

In 1948 he joined the Scientific Civil Service, and was appointed Principal Scientific Officer (PSO) at Services Electronic Research Laboratories, in Baldock in Hertfordshire, where he undertook research on microwaves, magnetrons, plasma physics and lasers.

He enjoyed sailing, owning two boats at Salcombe in Devon. He frequently went down there to the family holiday home with his wife Penelope, and his two sons, Christopher and Nicholas.

He retired in 1977 and died in Cambridge on 8 February 1983.

References

1917 births
People educated at King Edward's School, Birmingham
1983 deaths
English physicists
Radar pioneers
Alumni of the University of Birmingham
Scientists from Birmingham, West Midlands
Members of HM Scientific Civil Service
Civil servants in the Admiralty
20th-century Royal Navy personnel
20th-century English scientists
20th-century British physicists
20th-century British civil servants
Avalanche breakdown. Avalanche breakdown (or the avalanche effect) is a phenomenon that can occur in both insulating and semiconducting materials. It is a form of electric current multiplication that can allow very large currents within materials which are otherwise good insulators. It is a type of electron avalanche. The avalanche process occurs when carriers in the transition region are accelerated by the electric field to energies sufficient to create mobile or free electron-hole pairs via collisions with bound electrons.

Explanation

Materials conduct electricity if they contain mobile charge carriers.  There are two types of charge carriers in a semiconductor: free electrons (mobile electrons) and electron holes (mobile holes which are missing electrons from the normally-occupied electron states).  A normally-bound electron (e.g., in a bond) in a reverse-biased diode may break loose due to a thermal fluctuation or excitation, creating a mobile electron-hole pair (exciton).  If there is a voltage gradient (electric field) in the semiconductor, then the electron will move towards the positive voltage while the hole will move towards the negative voltage.  Usually, the electron and hole will simply move to opposite ends of the crystal and enter the appropriate electrodes. When the electric field is strong enough, the mobile electron or hole may be accelerated to speeds high enough to knock other bound electrons free, creating more free charge carriers, increasing the current and leading to further "knocking out" processes and creating an avalanche.  In this way, large portions of a normally-insulating crystal can begin to conduct.

The large voltage drop and possibly large current during breakdown necessarily leads to the generation of heat. Therefore, a diode placed into a reverse blocking power application will usually be destroyed by breakdown if the external circuit allows a large current. In principle, avalanche breakdown only involves the passage of electrons and need not cause damage to the crystal. Avalanche diodes (commonly encountered as high voltage Zener diodes) are constructed to break down at a uniform voltage and to avoid current crowding during breakdown. These diodes can indefinitely sustain a moderate level of current during breakdown.

The voltage at which the breakdown occurs is called the breakdown voltage.  There is a hysteresis effect; once avalanche breakdown has occurred, the material will continue to conduct even if the voltage across it drops below the breakdown voltage. This is different from a Zener diode, which will stop conducting once the reverse voltage drops below the breakdown voltage.

See also
QBD (electronics)
Single-photon avalanche diode
Spark gap
Zener breakdown

References
Microelectronic Circuit Design — Richard C Jaeger — 
The Art of Electronics — Horowitz & Hill — 
University of Colorado guide to Advance MOSFET design 

Power MOSFET avalanche characteristics and ratings - ST Application Note AN2344
 Power MOSFET Avalanche Design Guidelines - Vishay Application Note AN-1005

Electrical breakdown
Airespace. Airespace, Inc., formerly Black Storm Networks, was a networking systems company founded in 2001, manufacturing wireless access points and Controllers. The company developed the AP-Controller model for fast deployment and the Lightweight Access Point Protocol, the precursor to the CAPWAP protocol.

Corporate history 
Airespace was founded in 2001 by Pat Calhoun, Bob Friday, Bob O'Hara, and Ajay Mishra. The company was venture backed by Storm Ventures, Norwest Venture Partners, Fidelity Investments, and Battery Ventures. In 2003, it entered into an agreement to provide OEM equipment to NEC. In 2004 it signed an agreement with Alcatel and Nortel to provide equipment to the two companies on an OEM basis.

Airespace was first to market with integrated location tracking. Within a year and a half, the company grew rapidly into the market leader of enterprise Wi-Fi.

Cisco Systems acquired Airespace in 2005 for $450 million; this was one of 13 acquisitions Cisco made that year and the largest up to that point. Airespace products were merged into Cisco Aironet product line.

References

2001 establishments in California
2005 disestablishments in California
2005 mergers and acquisitions
American companies established in 2001
American companies disestablished in 2005
Cisco Systems acquisitions
Computer companies established in 2001
Computer companies disestablished in 2005
Defunct computer companies of the United States
Defunct computer hardware companies
Defunct networking companies
Networking hardware companies