omniomni/omni-engineering huggingface dataset:
Electric discharge. In electromagnetism, an  electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas (i.e., an outgoing flow of electric current through a non-metal medium).

Applications
The properties and effects of electric discharges are useful over a wide range of magnitudes. Tiny pulses of current are used to detect ionizing radiation in a Geiger–Müller tube. A low steady current can illustrate the gas spectrum in a gas-filled tube. A neon lamp is an example of a gas-discharge lamp, useful both for illumination and as a voltage regulator. A flashtube generates a short pulse of intense light useful for photography by sending a heavy current through a gas arc discharge. Corona discharges are used in photocopiers.

Electric discharges can convey substantial energy to the electrodes at the ends of the discharge. A spark gap is used in internal combustion engines to ignite the fuel/air mixture on every power stroke. Spark gaps are also used to switch heavy currents in a Marx generator and to protect electrical apparatus. In electric discharge machining, multiple tiny electric arcs erode a conductive workpiece to a finished shape. Arc welding is used to assemble heavy steel structures, where the base metal is heated to melting by the arc's heat. An electric arc furnace sustains arc currents of tens of thousands of amperes and is used for steelmaking and the production of alloys and other products.

Examples
Examples of electric discharge phenomena include:
Brush discharge
Dielectric barrier discharge
Corona discharge
Electric glow discharge
Electric arc
Electrostatic discharge
Electric discharge in gases
Leader (spark)
Partial discharge
Streamer discharge
Vacuum arc
Townsend discharge
St. Elmo's fire
Lightning
Electric organ

See also
 Debye sheath
 Electrical breakdown
 Electric discharge in gases
 Lichtenberg figure
 Space charge

References

Electrical phenomena
Plasma phenomena
Charles Bradford Sheppard. C. Bradford Sheppard was an American working as a radio engineer for Hazeltine Electronics during World War II. Sheppard, who worked on radar in the design office, wished to fight Nazi Germany in the armed forces but was turned down by the US Army due to blindness in one eye.  He then asked Soviet intelligence to arrange Soviet citizenship for himself and his family so that he could join the Soviet army.  When the Soviets made clear he would not be allowed to fight he broke off all contact.  Soviet intelligence assigned Sheppard the cover name MASTER or MASTER CRAFTSMAN.  

After World War II, C. Bradford Sheppard was part of the original Eckert & Mauchly team of electrical engineers who designed and built the first digital computers, notably the ENIAC, EDVAC, and UNIVAC machines.  In particular, he invented some of the first digital delay systems, also known as digital memory, which was based on sending sound waves down a mercury-filled cylinder.

C. Bradford Sheppard was one of the teachers in the original Moore School Lectures, given during the summer of 1946.
 
It is trivial to demonstrate that C. Bradford Sheppard was not a Soviet spy, as the Soviets never held information on the digital computers he helped develop as part of the Eckert-Mauchly Computer Corporation.  These allegations were part of the infamous McCarthy campaign and were rebutted by Mauchly himself when a hearing was eventually afforded him.

Venona

The following messages decrypted by the Venona project reference Sheppard:

1589, 1590 KGB New York to Moscow, 30 September 1943
886 KGB New York to Moscow, 22 June 1944
943 KGB New York to Moscow, 4 July 1944

References

Isaac L. Auerbach J. Presper Eckert, Robert F. Shaw and C. Bradford Sheppard, "Mercury Delay Line Memory Using a Pulse Rate of Several Megacycles, " Proceedings of the l.R.E., Aug. 1949, pp. 855.
John Earl Haynes and Harvey Klehr, Venona: Decoding Soviet Espionage in America (New Haven: Yale University Press, 1999).

American people in the Venona papers
Robert M. Allan. Robert M. Allan (born September 12, 1880) was a Canadian-born American politician. He was a member of the City Council in Los Angeles, California from 1921 to 1927.

Biography 

Born on September 12, 1880, in Saint John, New Brunswick, Canada, Allan was the son of Martin Smith Allan and Shara Neptune. He was educated in the public schools of Saint John until he was 18, when he emigrated to Boston, Massachusetts, United States, and finished his schooling there. He did "electrical experimental work" in Boston and moved to California in 1903, where he joined the Electrical Workers Union and worked with the Woodill-Hulse Electric Company and then with the Auto Vehicle Company. He began working in insurance and finance in 1905, then became president of the Guarantee Finance & Securities Company and vice-president of Insurance Plan Mutual Building and Loan. He later formed Allan MacMaster Company, of which he was senior partner.

Allan was married to Helen M. Urenn of Taylorville in 1907; they had two children, Robert M. Jr. and Lois. A Methodist and a Republican, Taylor was a member of the Jonathan, City, Breakfast, Casa Del Mar, Lakeside, El Caballero and San Pedro Golf clubs. His hobbies were golf and fishing.

After leaving the City Council, Allan returned to his private business interests.

Public life

City Council 

Allan was elected to the City Council in 1921 when the city used an at-large voting system and was reelected in 1923 under the same system. After the adoption of a new city charter in 1925, in which district voting was established, he was chosen as the first councilman from the city's 2nd District, which at that time covered Hollywood south of Franklin Avenue or Hollywood Boulevard and north of Santa Monica Boulevard, and including the Los Feliz district. He was reelected in 1925 but lost to Arthur Alber in 1927. It was said that Allan's loss that year was partly due to the voters' making a "clean sweep at the City Hall" of the council members allied with political boss Kent Kane Parrot.

Later service 

Allan was appointed to the city's Board of Public Works in 1933, and he there joined the city's retirement system. Some controversy was aroused in September 1941, long after he had left the board, when he applied for a pension. He had been hired as a meat inspector on August 4, 1940, but he was discharged by the Board of Health Commissioners fifteen days later because, the board said in a resolution, it appeared that he had been employed "primarily, if not solely, for the purpose of enabling him to be in the employ of the city at a time when he should file an application for a pension." It was said he would collect "$61.39 per month for life" after having paid in just $686 to the fund. The city attorney was asked if Allan's claim were valid. No response was publicly revealed.

References 

1880 births
Year of death missing
Canadian emigrants to the United States
Los Angeles City Council members
California Republicans
Bead test. The bead test is a traditional part of qualitative inorganic analysis to test for the presence of certain metals. The oldest one is the borax bead test or blister test. It was introduced by Berzelius in 1812. Since then other salts were used as fluxing agents, such as sodium carbonate or sodium fluoride. The most important one after borax is microcosmic salt, which is the basis of the microcosmic salt bead test.

Borax bead 
A small loop is made in the end of a platinum wire and heated in a Bunsen burner flame until red hot. A stick made of another inert substance such as a magnesia stick (MgO) may also be used.
It is then dipped into powdered borax and held in the hottest part of the flame where it swells up as it loses its water of crystallization and then shrinks, forming a colourless, transparent glass-like bead (a mixture of sodium metaborate and boric anhydride).

The bead is allowed to cool and then wetted and dipped into the sample to be tested such that only a tiny amount of the substance adheres to the bead. If too much substance is used, the bead will become dark and opaque. The bead and adhering substance is then heated in the lower, reducing, part of the flame, allowed to cool, and the colour observed. It is then heated in the upper, oxidizing, part of the flame, allowed to cool, and the colour observed again.

Characteristic coloured beads are produced with salts of copper, iron, chromium, manganese, cobalt and nickel. After the test, the bead is removed by heating it to fusion point, and plunging it into a vessel of water.

See also
Flame test

References

Chemical tests

ru:Перл (химия)
Sound baffle. A sound baffle is a construction or device which reduces the strength (level)  of airborne sound. Sound baffles are a fundamental tool of noise mitigation, the practice of minimizing noise pollution or reverberation. An important type of sound baffle is the noise barrier constructed along highways to reduce sound levels in the vicinity of properties. Sound baffles are also applied to walls and ceilings in building interiors to absorb sound energy and thus lessen reverberation.

Highway noise barriers

The technology for accurate prediction of the effects of noise barrier design using a computer model to analyze roadway noise has been available since the early 1970s. The earliest published scientific design of a noise barrier may have occurred in Santa Clara County, California in 1970 for a section of the Foothill Expressway in Los Altos, California. The county used a computer model to predict the effects of sound propagation from roadways, with variables consisting of vehicle speed, ratio of trucks to automobiles, road surface type, roadway geometrics, micro-meteorology and the design of proposed soundwalls.

Interior sound baffle design

Since the early 1900s, scientists have been aware of the utility of certain types of interior coatings or baffles to improve the acoustics of concert halls, theaters, conference rooms and other spaces where sound quality is important. By the mid-1950s, Bolt, Beranek and Newman and a few other U.S. research organizations were developing technology to address sound quality's design challenges. This design field draws on several disciplines including acoustical science, computer modeling, architecture and materials science. Sound baffles are also used in speaker cabinets to absorb energy from the pressure created by the speakers, thus reducing cabinet resonance.
 
In 1973, Pearl P. Randolph, a school bus driver in Virginia, won a new school bus in a national contest held by Wayne Corporation for the suggestion that sound baffles be installed in the ceiling of school buses. In 1981, they were first made mandatory by the state of California.

Vehicle exhaust sound baffles

Baffles are also found in the exhaust pipes of vehicles, particularly motorcycles.

See also

Noise pollution
Noise health effects

References

Ceilings
Noise pollution
Noise control
Entropy of vaporization. In thermodynamics, the entropy of vaporization is the increase in entropy upon vaporization of a liquid. This is always positive, since the degree of disorder increases in the transition from a liquid in a relatively small volume to a vapor or gas occupying a much larger space. At standard pressure , the value is denoted as  and normally expressed in joules per mole-kelvin, J/(mol·K).

For a phase transition such as vaporization or fusion (melting), both phases may coexist in equilibrium at constant temperature and pressure, in which case the difference in Gibbs free energy is equal to zero: 

where  is the heat or enthalpy of vaporization. Since this is a thermodynamic equation, the symbol  refers to the absolute thermodynamic temperature, measured in kelvins (K). The entropy of vaporization is then equal to the heat of vaporization divided by the boiling point:  

 

According to Trouton's rule, the entropy of vaporization (at standard pressure) of most liquids has similar values. The typical value is variously given as 85 J/(mol·K), 88 J/(mol·K) and 90 J/(mol·K). Hydrogen-bonded liquids have somewhat higher values of

See also
 Entropy of fusion

References 

Thermodynamic entropy
Thermodynamic properties
DTED. DTED (or Digital Terrain Elevation Data) is a standard of digital datasets which consists of a matrix of terrain elevation values, i.e., a Digital Elevation Model. This standard was originally developed in the 1970s to support aircraft radar simulation and prediction. Terrain elevations are described as the height above the Earth Gravitational Model 1996 (EGM96) geoid, not the WGS84 reference ellipsoid.

DTED supports many applications, including line-of-sight analyses, terrain profiling, 3-D terrain visualization, mission planning/rehearsal, and modeling and simulation.  DTED is a standard National Geospatial-Intelligence Agency (NGA) product that provides medium resolution, quantitative data in a digital format for military system applications that require terrain elevation. 

The DTED format for level 0, 1 and 2 is described in U.S. Military Specification Digital Terrain Elevation Data (DTED) MIL-PRF-89020B, and amongst other parameters describes the resolution for each level:

 Level 0 has a post spacing of approximately 900 meters.
 Level 1 has a post spacing of approximately 90 meters.
 Level 2 has a post spacing of approximately 30 meters.

The precise spacing is defined by dividing the world into zones based on latitude, and is given in the following table:

In addition three more levels (3, 4 and 5) at increasing resolution have been proposed, but not yet standardized.

DTED data is stored in a big endian format where negative numbers are signed magnitude.

References

External links

FAS: Digital Terrain Elevation Data [DTED]
DTED at National Geospatial-Intelligence Agency website
DTED specification
MATLAB has in its Mapping toolbox a function for reading DTED files: source code documentation

Radar
Cartography
Digital elevation models
GIS raster file formats
Infrared detector. An infrared detector is a detector that reacts to infrared (IR) radiation. The two main types of detectors are thermal and photonic (photodetectors).

The thermal effects of the incident IR radiation can be followed through many temperature dependent phenomena.
Bolometers and  microbolometers are based on changes in resistance. Thermocouples and thermopiles use the thermoelectric effect. Golay cells follow thermal expansion. In IR spectrometers the pyroelectric detectors are the most widespread.

The response time and sensitivity of photonic detectors can be much higher, but usually these have to be cooled to cut thermal noise. The materials in these are semiconductors with narrow band gaps. Incident IR photons can cause electronic excitations. In photoconductive detectors, the resistivity of the detector element is monitored. Photovoltaic detectors contain a p-n junction on which photoelectric current appears upon illumination.

An infrared detector is hybridized by connecting it to a readout integrated circuit with indium bumps. This hybrid is known as a focal plane array.

Detector materials
The materials basis for infrared detection devices are narrow-gap semiconductors, including compounds and alloys of bismuth, antimony, indium, cadmium, selenium and others.

 Lead(II) sulfide (PbS)
 Mercury cadmium telluride (Known as MCT, HgCdTe)
 Indium antimonide (InSb)
 Indium arsenide
 Indium gallium arsenide
 Lead selenide
 QWIP
 Lithium tantalate (LiTaO3)
 Triglycine sulfate (TGS)
 Platinum silicide (PtSi)

See also
 Infrared imaging

References

Detectors
Image sensors
Infrared imaging
Task Control Block. The Task Control Block (TCB) contains the state of a task in, e.g., OS/360 and successors on IBM System/360 architecture and successors.

The TCB in OS/360 and successors
In OS/360, OS/VS1, SVS, MVS/370, MVS/XA, MVS/ESA, OS/390 and z/OS, the TCB contains, among other data, non-dispatchability flags and the general and floating point registers for a task that is not currently assigned to a CPU.

A TCB provides an anchor for a linked list of other, related request blocks (RBs); the top-linked RB for a TCB contains the Program status word (PSW) when the task is not assigned to a CPU.

When the control program's dispatcher selects a TCB to be dispatched, the dispatcher loads registers from the TCB and loads the PSW from the top RB of the TCB, thereby dispatching the unit of work.

Request Blocks

OS/360 has the following types of request blocks
 Interruption Request Block 
 An IRB is used to handle an asynchronous exit.
 Program Request Block
 A PRB represents a module invoked with an ATTACH macro, a LINK macro or a synchronous exit. 
 System Interruption Request Block
 An SIRB is used to run I/O error recovery code.
 Supervisor Request Blocks 
 An SVRB represents the execution of a Type 2, Type 3 or Type 4 SVC routine

An RB contains several fields, among them an old PSW, old general registers, a PSW and a wait count.

Dispatching
The Dispatcher is a routine in the nucleus that selects the work to be dispatched. It selects the highest priority task that:
Is not running on another CPU
Does not have any non-dispatchability flags set
Has a top RB with a zero wait count.

The system maintains a pair of TCB pointers known as TCB old and TCB new. A TCB new pointer of zero causes the dispatcher to search for an eligible task.

When the dispatcher finds an eligible task, it sets the old and new TCB pointers. loads the registers from the TCB and loads the PSW from the top RB.

If the dispatcher fails to find eligible work, it enters an enabled wait.

History
With the introduction of MVS/370 and successor systems, a whole new environment was introduced: the Service Request Block (SRB), which generally has a higher priority than any Task Control Block, and, indeed, which itself has two distinct priorities: a Global SRB (priority over all local address space SRBs and TCBs) and a Local SRB (priority over only the local address space TCBs); and MVS's dispatcher must manage all of these with absolute consistency across as many as two processors (MVS/370) and as many as sixteen processors (successor systems).

See also
Process control block

Notes

References

Process (computing)
Q meter. A Q meter is a piece of equipment used in the testing of radio frequency circuits. It has been largely replaced in professional laboratories by other types of impedance measuring devices, though it is still in use among radio amateurs. It was developed at Boonton Radio Corporation in Boonton, New Jersey in 1934 by William D. Loughlin.

Description
A Q meter measures the quality factor of a circuit, Q, which expresses how much energy is dissipated per cycle in a non-ideal reactive circuit:

This expression applies to an RF and microwave filter, bandpass LC filter, or any resonator. It also can be applied to an inductor or capacitor at a chosen frequency. For inductors

Where  is the reactance of the inductor,  is the inductance,  is the angular frequency and  is the resistance of the inductor. The resistance  represents the loss in the inductor, mainly due to the resistance of the wire. A Q meter works on the principle of series resonance.

For LC band pass circuits and filters:

Where  is the resonant frequency (center frequency) and  is the filter bandwidth. In a band pass filter using an LC resonant circuit, when the loss (resistance) of the inductor increases, its Q factor is reduced, and so the bandwidth of the filter is increased. In a coaxial cavity filter, there are no inductors and capacitors, but the cavity has an equivalent LC model with losses (resistance) and the Q factor can be applied as well.

Operation

Internally, a minimal Q meter consists of a tuneable RF generator with a very low (pass) impedance output and a detector with a very high impedance input. There is usually provision to add a calibrated amount of high Q capacitance across the component under test to allow inductors to be measured in isolation. The generator is effectively placed in series with the tuned circuit formed by the components under test, and having negligible output resistance, does not materially affect the Q factor, while the detector measures the voltage developed across one element (usually the capacitor) and being high impedance in shunt does not affect the Q factor significantly either. 

The ratio of the developed RF voltage to the applied RF current, coupled with knowledge of the reactive impedance from the resonant frequency, and the source impedance, allows the Q factor to be directly read by scaling the detected voltage.

See also
 LCR meter
 ESR meter

References

Further reading

"An experimental 'Q' meter" — article by Lloyd Butler (originally published in Amateur Radio, November 1988; revised April 2004)
 

Electronic test equipment
Radio electronics
Measuring instruments
Turkish National Research Institute of Electronics and Cryptology. The National Research Institute of Electronics and Cryptology of Turkey (), shortly UEKAE, is a national scientific organization with the aim of developing advanced technologies for information security. UEKAE is the most prominent and also the founder (first) institute of the TÜBİTAK.

The institute was founded by Yılmaz Tokad, professor at ITU (Istanbul Technical University), and four researchers under his supervision in the building of engineering at METU (Middle East Technical University)in 1972, with the name Electronic Research Unit. In 1995 the institute's name has become National Research Institute of Electronics and Cryptology and moved to Gebze, Kocaeli.

Affiliates and facilities
It is affiliated with the TÜBİTAK Informatics and Information Security Research Center (BİLGEM), which is bound to Scientific and Technological Research Council of Turkey (TUBİTAK). The institute was later reorganized as the prime institute of the BİLGEM in the Gebze, Kocaeli Province campus of TÜBİTAK.

The institute consists of facilities on fields and for products as follows:
 Semiconductor Technologies Research Laboratory (YITAL)
 Cryptanalysis Center
 EMC/Tempest Test Center
 Speech and Language Technologies
 Software Development
 Surveillance Systems
 Communication and Information Security
 Electro-Optics Laboratory
 Spectrum Analysis and Management
 Open Source Software
 Government Cerficiation Authority (KSM)
 NATO Certified Products

See also
TÜBİTAK Informatics and Information Security Research Center  (TÜBİTAK BİLGEM)
Scientific and Technological Research Council of Turkey (TÜBİTAK)
Turkish Academy of Sciences (TÜBA)
Turkish Atomic Energy Authority (TAEK)
 Pardus, a Linux distribution

References

External links
 Official website of the institute 

Research institutes in Turkey
Defence companies of Turkey
Scientific and Technological Research Council of Turkey
Organizations established in 1994
1994 establishments in Turkey
Organizations based in Gebze