omniomni/omni-engineering huggingface dataset:
Narrow-gap semiconductor. Narrow-gap semiconductors are semiconducting materials with a magnitude of bandgap that is smaller than 0.7 eV, which corresponds to an infrared absorption cut-off wavelength over 2.5 micron. A more extended definition includes all semiconductors with bandgaps smaller than silicon (1.1 eV). Modern terahertz, infrared, and thermographic technologies are all based on this class of semiconductors.

Narrow-gap materials made it possible to realize satellite remote sensing, photonic integrated circuits for telecommunications, and unmanned vehicle Li-Fi systems, in the regime of Infrared detector and infrared vision. They are also the materials basis for terahertz technology, including security surveillance of concealed weapon uncovering, safe medical and industrial imaging with terahertz tomography, as well as dielectric wakefield accelerators. Besides, thermophotovoltaics embedded with narrow-gap semiconductors can potentially use the traditionally wasted portion of solar energy that takes up ~49% of the sun light spectrum. Spacecraft, deep ocean instruments, and vacuum physics setups use narrow-gap semiconductors to achieve cryogenic cooling.

List of narrow-gap semiconductors 

{| class="wikitable"
|-
!Name
!Chemical formula
!Groups
!Band gap (300 K)
|-
| Mercury cadmium telluride
| Hg1−xCdxTe
| II-VI
| 0 to 1.5 eV
|-
| Mercury zinc telluride
| Hg1−xZnxTe
| II-VI
| 0.15 to 2.25 eV
|-
| Lead selenide
| PbSe
| IV-VI
| 0.27 eV
|-
| Lead(II) sulfide
| PbS
| IV-VI
| 0.37 eV
|-
| Telenium
| Te
| VI
| ~0.3 eV 
|-
| Lead telluride
| PbTe
| IV-VI
| 0.32 eV
|-
| Magnetite
| Fe3O4
| Transition Metal-VI
| 0.14 eV
|-
| Indium arsenide
| InAs
| III-V
| 0.354 eV
|-
| Indium antimonide
| InSb
| III-V
| 0.17 eV
|-
| Germanium
| Ge
| IV 
| 0.67 eV
|-
|Gallium antimonide
| GaSb
| III-V
| 0.67 eV
|-
| Cadmium arsenide
| Cd3As2
| II-V
| 0.5 to 0.6 eV
|-
| Bismuth telluride
| Bi2Te3
|
| 0.21 eV
|-
| Tin telluride
| SnTe
| IV-VI
| 0.18 eV
|-
| Tin selenide
| SnSe
| IV-VI
| 0.9 eV
|-
| Silver(I) selenide
| Ag2Se
|
| 0.07 eV
|-
|Magnesium silicide
|Mg2Si
|II-IV
|0.79 eV
|}

See also 
 List of semiconductor materials
 Wide-bandgap semiconductor

References

Further reading 
 Dornhaus, R., Nimtz, G., Schlicht, B. (1983). Narrow-Gap Semiconductors. Springer Tracts in Modern Physics 98,  (print)  (online) 
 

Semiconductor material types
Densitometry. Densitometry is the quantitative measurement of optical density in light-sensitive materials, such as photographic paper or photographic film, due to exposure to light.

Overview
Optical density is a result of the darkness of a developed picture and can be expressed absolutely as the number of dark spots (i.e., silver grains in developed films) in a given area, but usually it is a relative value, expressed in a scale.

Since density is usually measured by the decrease in the amount of light which shines through a transparent film, it is also called absorptiometry, the measure of light absorption through the medium. The corresponding measuring device is called a densitometer (absorptiometer). The decadic (base-10) logarithm of the reciprocal of the transmittance is called the absorbance or density.

DMax and DMin refer to the maximum and minimum density that can be produced by the material. The difference between the two is the density range. The density range is related to the exposure range (dynamic range), which is the range of light intensity that is represented by the recording, via the Hurter–Driffield curve. In the context of photography, the dynamic range is often measured in "stops", which is the binary logarithm of the ratio of highest and lowest distinguishable exposures; in an engineering context, the dynamic range is usually given by its decadic logarithm expressed in decibels.

Uses

According to the principle of operation of the densitometer, one can have:
 spot densitometry: the value of light absorption is measured at a single spot
 line densitometry: the values of successive spots along a dimension are expressed as a graph
 bidimensional densitometry: the values of light absorption are expressed as a 2D synthetic image, usually using false-color shading

Dual-energy X-ray absorptiometry is used in medicine to evaluate calcium bone density, which is altered in several diseases such as osteopenia and osteoporosis. Special devices have been developed and are in current use for clinical diagnosis, called bone densitometers.

See also 
 Sensitometry

References

External links
 Fundamentals of Densitometry, by Mark Vivino, National Institute of Health

Optical metrology
Digital Data Communications Message Protocol. Digital Data Communications Message Protocol (DDCMP) is a byte-oriented communications protocol devised by Digital Equipment Corporation in 1974 to allow communication over point-to-point network links for the company's DECnet Phase I network protocol suite. The protocol uses full or half duplex synchronous and asynchronous links and allowed errors introduced in transmission to be detected and corrected. It was retained and extended for later versions of the DECnet protocol suite. DDCMP has been described as the "most popular and pervasive of the commercial byte-count data link protocols".

See also
DEX

References 
 Overview of the protocol
 Protocol specification (courtesy of DEC)

Notes

Network protocols
Cuthbert A. Brereton. Cuthbert Arthur Brereton (17 September 1850 – 12 September 1910) was a civil engineer and a partner of Sir John Wolfe Barry. Together they completed numerous projects in England and Wales, the most prominent being the King Edward VII Bridge over the Thames at Kew, London.

Also with Barry he had been involved with the construction of Barry Docks and railways, the Middlesbrough Docks, the Surrey Commercial docks, and the great Northern, District & and Piccadilly underground lines. He had previously been resident engineer to the Llynvi and Ogmore Railways, and the Portcawl Docks and was afterwards assistant engineer on the London Inner Circle railway. He built the Ladykirk and Norham Bridge over the River Tweed. He was a lieut. colonel of the Engineer and Railway Staff Corps.

He was elected to the Smeatonian Society in 1896 and became their president in July 1909 until his death.

Born in Brinton, Cuthbert came from a Norfolk family that produced other notable Victorian engineers R.P. Brereton (Isambard Kingdom Brunel's Chief Assistant) and R.M.Brereton chief engineer on the Bombay, Nagpore, and Calcutta portion of the Great Indian Peninsular Railway, 1867–70, and advocate in the US Congress for the building of irrigation canals in California.

References

English civil engineers
Presidents of the Smeatonian Society of Civil Engineers
1850 births
1910 deaths
People from Brinton, Norfolk
Engineer and Railway Staff Corps officers
19th-century British Army personnel
Military personnel from Norfolk
CMRR. CMRR may stand for:

 Catskill Mountain Railroad, operators of the former New York Central Railroad Catskill Mountain Branch from Kingston to Phoenicia
 Central Massachusetts Railroad, former railroad forming part of the Boston and Maine Railroad system
 Common-mode rejection ratio, measure of the capability of an instrument to reject a signal that is common to both input leads
 Chemistry and Metallurgy Research Replacement Facility, nuclear facility at Los Alamos National Laboratory
Regulator (automatic control). In automatic control, a regulator is a device which has the function of maintaining a designated characteristic. It performs the activity of managing or maintaining a range of values in a machine. The measurable property of a device is managed closely by specified conditions or an advance set value; or it can be a variable according to a predetermined arrangement scheme. It can be used generally to connote any set of various controls or devices for regulating or controlling items or objects.

Examples are a voltage regulator (which can be a transformer whose voltage ratio of transformation can be adjusted, or an electronic circuit that produces a defined voltage), a pressure regulator, such as a diving regulator, which maintains its output at a fixed pressure lower than its input, and a fuel regulator (which controls the supply of fuel).

Regulators can be designed to control anything from gases or fluids, to light or electricity. Speed can be regulated by electronic, mechanical, or electro-mechanical means. Such instances include; 
 Electronic regulators as used in modern railway sets where the voltage is raised or lowered to control the speed of the engine
 Mechanical systems such as valves as used in fluid control systems. Purely mechanical pre-automotive systems included such designs as the Watt centrifugal governor whereas modern systems may have electronic fluid speed sensing components directing solenoids to set the valve to the desired rate.
 Complex electro-mechanical speed control systems used to maintain speeds in modern cars (cruise control) - often including hydraulic components, 
 An aircraft engine's constant speed unit changes the propeller pitch to maintain engine speed.

See also
Controller (control theory)
Governor (device)
Process control

Control engineering
Robert L. Cook. Robert L. Cook (December 10, 1952) is a computer graphics researcher and developer, and the co-creator of the RenderMan rendering software. His contributions are considered to be highly influential in the field of animated arts.

In 2009, Cook was elected a member of the National Academy of Engineering for building the motion picture industry's standard rendering tool.

Cook was born in Knoxville, Tennessee and educated at Duke University and Cornell University. While at Cornell, Cook worked with Donald P. Greenberg.

Education
B.S. in physics, 1973, Duke University, N.C.
M.S. in computer graphics, 1981, Cornell University, Ithaca, N.Y.

Career

Robert Cook was involved with Lucasfilm and later had the position as Vice President of Software Development at Pixar Animation Studios, which he left in 1989. In November 2016, he became the Commissioner of the Technology Transformation Service of the U.S. General Services Administration.

Computer Animation Rendering
 Star Trek II: The Wrath of Khan (1982) computer graphics: Industrial Light & Magic
 André and Wally B. (1984) 3D rendering
 Luxo, Jr. (1986) rendering
 Red's Dream (1987) reyes / miracle tilt
 Toy Story (1995) renderman software development
 Toy Story 2 (1999) rendering software engineer
 Monsters, Inc. (2001) software team lead
 Cars (2006) software team lead
 Up (2009) software development: Pixar studio team

Awards
 1987, ACM SIGGRAPH Achievement Award in recognition of his contributions to the fields of computer graphics and visual effects.
 1992, Scientific and Engineering Award for the development of "RenderMan" software which produces images used in motion pictures from 3D computer descriptions of shape and appearance.
 1999, Fellow of the Association for Computing Machinery.
 2000, Academy Award of Merit (Oscar) for significant advancements to the field of motion picture rendering as exemplified in Pixar's RenderMan. Their broad professional influence in the industry continues to inspire and contribute to the advancement of computer-generated imagery for motion pictures.
 GATF InterTech Award
 MacWorld World Class Award
 Seybold Award for Excellence
 2009, The Steven Anson Coons Award for Outstanding Creative Contributions to Computer Graphics
 2009, Elected to the National Academy of Engineering

References

1952 births
Living people
American animators
American computer scientists
American physicists
Computer graphics professionals
Cornell University alumni
Duke University alumni
People from Knoxville, Tennessee
1999 fellows of the Association for Computing Machinery
Members of the United States National Academy of Engineering
Lucasfilm people
Pixar people
Jean-Jacques Dordain. Jean-Jacques Dordain (born 14 April 1946) was Director General of the European Space Agency between 2003 and 2015.

Graduating at École Centrale Paris in 1968, Dordain began his scientific career in the French Aerospace Research Agency (ONERA) and later worked as a professor at the National Higher School of Aeronautics and Aerospace in the 1970s and 1980s. He has conducted extensive research in rocket engines and microgravity experiments. He was also a European astronaut candidate.

In 1998 he was Executive Secretary at the Japanese Space Agency (then NASDA, now JAXA) and later started as Director of Launchers at ESA, where he became Director General in July 2003.

He also holds the honorary function of Chancellor of the International Space University.

On 1 July 2015, he was succeeded as Director General of the ESA by Johann-Dietrich Woerner of Germany.

In 2019, Dordain was elected as a member into the National Academy of Engineering for contributions to complex space systems and leadership of space exploration programs worldwide.

References

   7.https://odysseeceleste.com/jean-jacques-dordain-directeur-general-de-lagence-spatiale-europeenne-2003-a-2015/ [archive], portrait-interview de l'association odyssée céleste par Halim Bennadja

External links
Spacefacts biography of Jean-Jacques Dordain

1946 births
Living people
21st-century French businesspeople
European Space Agency personnel
École Centrale Paris alumni
SSEM. SSEM can refer to:
 Manchester Baby or Small-Scale Experimental Machine, historic computer
 South Seas Evangelical Mission, missionary organization in the Solomon Islands
 Serial-section electron microscopy (ssEM), a form of transmission electron microscopy

Abreviación de la Secretaria de Seguridad del Estado de México S.S.E.M. (Policía del Estado de México) anteriormente Comisión Estatal de Seguridad Ciudadana (CES) y que se le modifico el nombre al tomar posesión de la gobernatura el Lic. Alfredo del Mazo 2017.
Flodin process. The Flodin process is a direct reduction process for manufacturing modern iron and steel, developed by Gustaf Henning Flodin from Sweden and patented in 1924. It has been used in Norway, Sweden, and the United States. Using a specially constructed electric arc furnace, a mixture of hematite with +0.2% carbon content and coal (or charcoal) is smelted in a continuous process, with the reduced metal accumulating at the bottom of the furnace, where it can be tapped off. Carbon content in the product can be controlled by changing the quantity of coal in the furnace. Noncorroding chromium steel could also be produced by using impure ore instead of hematite. Likewise, spongy iron can be cast by using coal-lime briquettes. Additionally, the Flodin furnace also can be used to produce so-called 'soft steel'.

References 

Steelmaking
Swedish inventions
Caledonite. Caledonite, whose name derives from Caledonia, the historical name of its place of discovery (Scotland), is a richly colored blue-green sulfate-carbonate mineral of lead and copper with an orthorhombic crystal structure. It is an uncommon mineral found in the oxidized zones of copper-lead deposits.

Collectible properties

Caledonite's primary use is a collector's mineral. Although it contains copper and lead, it is a secondary mineral and is not prevalent enough in any known deposits to be used as an ore. Caledonite, when developed into full crystals, can have a deep blue-green color reminiscent of secondary copper minerals. Its high lustre, on the other hand, is more like secondary lead minerals. Localities in which caledonite occurs as well developed crystals are quite rare and include the Mammoth-St. Anthony Mine at Tiger, Arizona, a few mines in California, such as the Reward Mine. A few other mines in Arizona and Chile have been known to produce samples.

Associated minerals
Given that caledonite is found in oxidized copper/lead deposits, it is frequently found in association with other copper and lead minerals. Frequently associated minerals include:  linarite, malachite, cerussite, brochantite, anglesite, leadhillite, and azurite.

Notes for identification
Caledonite's blue color is a useful indicator, but insufficient, especially since one of its associates, linarite, is a vivid blue as well. Useful tests for determining if a specimen is caledonite include its density, streak, and crystal habit.

References

Mineral Galleries

Lead minerals
Copper minerals
Sulfate minerals
Orthorhombic minerals
Minerals in space group 31
Minerals described in 1832
Hyalite. Hyalite is a transparent form of opal with a glassy lustre. It may exhibit an internal play of colors if natural inclusions are present. It is also called Muller's glass, water opal, and jalite. Müller's glass is named after its discoverer, Franz-Joseph Müller von Reichenstein.

Properties
Hyalite has a hardness of 5.5–6 on the Mohs scale and a specific gravity of 1.9–2.1. Lacking a plane of cleavage, it has a conchoidal fracture. The transparent or translucent mineraloid has a globular structure, a vitreous luster, and a white streak. Hyalite is an amorphous form of silica (SiO2) formed as a volcanic sublimate in volcanic or pegmatic rock and is thereby considered a mineraloid. It contains 3–8% water, either as a silanol group or in molecular form.

Uses
Opalescent hyalite is used in jewellery, and well-formed samples are of interest to collectors due to their unusual appearance, mode of formation and relative rarity.  It is sometimes mistaken for resin opal or silica glass since they both may appear clear and globular, but it can be identified under ultraviolet light due to its bright green fluorescence.

External links
Mindat data
Explanation from Fluorescent Mineral Society

Opals
List of Aerolíneas Argentinas destinations. Aerolíneas Argentinas was formed by the Argentine's Ministry of Transport as a state corporation in , when it took over the routes and assets of four struggling airlines. A year and a half later, in late , the company introduced the Buenos Aires–Rio de Janeiro–Natal–Dakar–Lisbon–Paris–Frankfurt route, using 48-seater DC-6 equipment, linking Argentina with Germany for the first time since 1933. By , the carrier's route network was  long. Upon taking delivery of the first three Comet 4s, which also became the first jetliners in the airline's fleet, these brand new aircraft were deployed on the Buenos Aires–London, Buenos Aires–New York City, and Buenos Aires–Santiago de Chile routes.

, the airline's top five international routes in terms of available seat kilometre (ASK) were Buenos Aires-Ezeiza–Madrid-Barajas, Buenos Aires-Ezeiza–Miami, Buenos Aires-Ezeiza–Barcelona, Buenos Aires-Ezeiza–Rome-Fiumicino and Buenos Aires-Ezeiza–Sydney; European routes account for about 41% of total ASK. In , the airline was granted permission to operate services to Atlanta, Detroit, Guangzhou, Las Vegas and Tel Aviv, yet it was announced it would not fly to these destinations with its own aircraft in the near future. In , the carrier announced the discontinuance of services to Sydney starting in . Aerolíneas had previously served Sydney via Auckland until the city was removed from the airline international network in . After leaving the Buenos Aires–New York JFK market unserved since 2008, Aerolíneas Argentinas resumed these flights in . , the airline top five domestic airports by available seats are Aeroparque Jorge Newbery, Ingeniero Aeronáutico Ambrosio L.V. Taravella International Airport, Ministro Pistarini International Airport, San Carlos de Bariloche Airport and Comandante Armando Tola International Airport.

List

Following is a list of destinations the airline flies to, . Destinations in the list below are presented by country, and for each of them the cities served are provided, along with the airport served. The list also includes airports that serve either as a hub or as a focus city for the airline, as well as destinations served on a seasonal basis. Terminated destinations are also listed, yet for Aerolíneas Argentinas only.

See also

Notes

References

External links 

Lists of airline destinations
Aerolíneas Argentinas
SkyTeam destinations
Johann Heinrich Schulze. Johann Heinrich Schulze (12 May 1687 – 10 October 1744) was a German professor and polymath.

History
Schulze studied medicine, chemistry, philosophy and theology and became a professor in Altdorf and Halle for anatomy and several other subjects.

Notable discoveries

Schulze is best known for his discovery that the darkening in sunlight of various substances mixed with silver nitrate is due to the light, not the heat as other experimenters believed, and for using the phenomenon to temporarily capture shadows.

Schulze's experiments with silver nitrate were undertaken in about 1717. He found that a slurry of chalk and nitric acid into which some silver had been dissolved was darkened by sunlight, but not by exposure to the heat from a fire. To provide an interesting demonstration of its darkening by light, he applied stencils of words to a bottle filled with the mixture and put it in direct sunlight, which produced copies of the text in dark characters on the surface of the contents. The impressions persisted until they were erased by shaking the bottle or until overall exposure to light obliterated them. Because they were produced by the action of light, an extremely broad and literal definition of what a photograph is may allow even these fluid, ephemeral sun printings to qualify as such, and on that basis many German sources and some international ones credit Schulze as the inventor of photography.

Though Schulze's work did not provide a means of permanently preserving an image, it did provide a foundation for later efforts toward that end. Thomas Wedgwood and Humphry Davy produced more substantial but still impermanent shadow images on coated paper and leather around the year 1800. Nicéphore Niépce succeeded in photographing camera images on paper coated with silver chloride in 1816 but he, too, could not make his results light-fast. The first permanent camera photograph of this type was made in 1835 by Henry Fox Talbot.

Works
 Abhandlung von der Stein-Chur durch innerliche Artzeneyen überhaupt und insonderheit von der neulich bekannt gewordenen Englischen . Franckfurt, 1740 Digital edition by the University and State Library Düsseldorf
 Chemische Versuche . Waysenhaus, Halle 1745 Digital edition by the University and State Library Düsseldorf

References

1687 births
1744 deaths
People from the Duchy of Magdeburg
Photography in Germany
Precursors of photography
Academic staff of the University of Altdorf
University of Halle alumni
Academic staff of the University of Halle
Acetic acid (data page). This page provides supplementary chemical data on acetic acid.

Material Safety Data Sheet  

The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source and follow its directions. 
PTCL Safety web site
Science Stuff

Structure and properties

Thermodynamic properties

Vapor pressure of liquid

Table data obtained from CRC Handbook of Chemistry and Physics 44th ed.

Distillation data

Spectral data

References 

Chemical data pages
Chemical data pages cleanup