omniomni/omni-engineering huggingface dataset:
Nernst lamp. The Nernst lamp was an early form of incandescent lamp.

Construction  
Nernst lamps did not use a glowing tungsten filament. Instead, they used a ceramic rod that was heated to incandescence. Because the rod (unlike tungsten wire) would not further oxidize when exposed to air, there was no need to enclose it within a vacuum or noble gas environment; the burners in Nernst lamps could operate exposed to the air and were only enclosed in glass to isolate the hot incandescent emitter from its environment. A ceramic of zirconium oxide – yttrium oxide was used as the glowing rod.

Efficiency 
Developed by the German physicist and chemist Walther Nernst in 1897 at the University of Göttingen, these lamps were about twice as efficient as carbon-filament lamps and emitted a more "natural" light (more similar in spectrum to daylight).
The lamps were quite successfully marketed for a time, although they eventually lost out to the more efficient tungsten-filament incandescent light bulb.
One disadvantage of the Nernst design was that the ceramic rod was not electrically conductive at room temperature, so the lamps needed a separate heater filament to heat the ceramic sufficiently to begin conducting electricity.

Manufacturing 
In the U.S., Nernst sold the patent to George Westinghouse, who founded the Nernst Lamp Company at Pittsburgh in 1901.
Minerals for the production of the glowers were extracted from the company's own mines at the legendary Barringer Hill, Texas (since 1937 submerged beneath the waters of Lake Buchanan).
By 1904 a total of over 130,000 Nernst lamps had been placed in service throughout the country.

In Europe, the lamps were produced by the German Allgemeine Elektrizitäts-Gesellschaft (AEG, General Electricity Company) at Berlin.
At the 1900 World's Fair held in Paris, the pavilion of the AEG was illuminated by 800 Nernst lamps, which was said to be quite spectacular at the time.

Scientific use 
In addition to their usage for ordinary electric illumination, Nernst lamps were used in one of the first practical long-distance photoelectric facsimile (fax) systems, designed by professor Arthur Korn in 1902, and in Allvar Gullstrand's original slit lamp (1911) which is used for ophthalmology to allow physicians to view the inside of a patient's eye and contributed to Gullstrand's Nobel Prize award.

Even after Nernst lamps became obsolete as visible lamps, "Nernst glowers" continue to be used as the infrared-emitting source used in IR spectroscopy devices. Their emission of infrared makes them inefficient as visible light sources, but perfect for IR spectroscopy applications.  Silicon carbide Globars now compete for this purpose as they are conductive even at room temperature and therefore need no preheating.

See also 
Globar, a silicon carbide rod used as thermal light source for infrared spectroscopy
List of light sources

References

External links

 

  - video showing the lamp in operation.

Walther Nernst
Products introduced in 1897
Incandescent light bulbs
Molecular autoionization. In chemistry, molecular autoionization (or self-ionization) is a chemical reaction between molecules of the same substance to produce ions. If a pure liquid partially dissociates into ions, it is said to be self-ionizing. In most cases the oxidation number on all atoms in such a reaction remains unchanged. Such autoionization can be protic ( transfer), or non-protic.

Examples

Protic solvents
Protic solvents often undergo some autoionization (in this case autoprotolysis):

2 H2O <=> H3O+ + OH-
The self-ionization of water is particularly well studied, due to its implications for acid-base chemistry of aqueous solutions.

2 NH3 <=> NH4+ + NH2-

2 H2SO4 <=> H3SO4+ + HSO4- 

3 HF <=> H2F+ + HF2-
Here proton transfer between two HF combines with homoassociation of  and a third HF to form

Non-protic solvents
2 PF5 <=> PF6- + PF4+

N2O4 <=> NO+ + NO3-
 Here the nitrogen oxidation numbers change from (+4 and +4) to (+3 and +5).

2 BrF3 <=> BrF2+ + BrF4-

These solvents all possess atoms with odd atomic numbers, either nitrogen or a halogen.  Such atoms enable the formation of singly charged, nonradical ions (which must have at least one odd-atomic-number atom), which are the most favorable autoionization products.  Protic solvents, mentioned previously, use hydrogen for this role.  Autoionization would be much less favorable in solvents such as sulfur dioxide or carbon dioxide, which have only even-atomic-number atoms.

Coordination chemistry
Autoionization is not restricted to neat liquids or solids.  Solutions of metal complexes exhibit this property.  For example, compounds of the type  (where X = Cl or Br) are unstable with respect to autoionization forming .

See also
Ionization
Ion association

References

Molecular physics
Hyper-interactive teaching technology. Hyper-interactive teaching technology or H-ITT is a form of technology used primarily to interact between the students and teachers.  Students generally are given an H-ITT transmitter, which is similar to a remote control, which allows them to answer questions in poll or quiz form.

It also means that the interaction between the teacher, the students and among the students is very high. The term is frequently used to denote a constant conversation among the students themselves, and learning with each other, which is not usually the case in a conventional teaching medium.

Educational technology
Austin Group. The Austin Group or the Austin Common Standards Revision Group is a joint technical working group formed to develop and maintain a common revision of POSIX.1 and parts of the Single UNIX Specification. It is named after the location of the first meeting in Austin, Texas.

The approach to specification development is "write once, adopt everywhere", with the deliverables being a set of specifications that carry the IEEE POSIX designation, The Open Group's Technical Standard designation, and the ISO/IEC designation. The new set of specifications is simultaneously ISO/IEC/IEEE 9945, and forms the core of the Single UNIX Specification Version 3. The IEEE formerly designated this standard as 1003.1.

This unique development combines both the industry-led efforts and the formal standardization activities into a single initiative, and includes a wide spectrum of participants.

The group currently has approximately 500 participants, and is chaired by Andrew Josey from The Open Group. The Open Group manages the day-to-day running of the group, providing the chair, the editor and email and web facilities. There are no fees for participation or membership.

The decision-making process is divided between the three entities that publish the resulting standard: ISO/IEC (Joint Technical Committee 1, subcommittee 22, working group 15), IEEE PASC (Portable Applications Standards Committee) and The Open Group, with each of these appointing an Organisational Representative (OR). The three ORs judge if there is consensus, and are responsible for initiating ballots within their respective organisations as required.

References

External links 
 Official Website

POSIX
Working groups
McElhanney. McElhanney Ltd. is a Western Canadian-based consulting firm that provides engineering, geomatics (surveying and mapping), geospatial, environmental, planning, and landscape architecture services. In operation since 1910, it is the oldest employee-owned engineering and geomatics firm in Canada, with its corporate headquarters in Vancouver, British Columbia.

History
The company was founded in 1910 by William Gordon McElhanney who surveyed the wilds outside burgeoning Vancouver. 
Between the 1920s to 1950s, the company saw success through significant projects such as the Lions Gate Bridge Alignment, Trans Mountain Pipeline, Kemano Tunnel Surveys & Hydro Power Tunnel, and the Stewart-Cassiar Highway projects, while navigating through hardship during the Great Depression (1929 to 1939). W.G. McElhanney retired in 1956, following completion of the firm's first international project, Survey of the Mekong River.

Following W.G. McElhanney's departure and after navigating through four more recessions (1980 to 1982, 1991, 2008, 2014), the firm split into three sister companies known as McElhanney Consulting Services Ltd. (MCSL), McElhanney Legal Survey Limited (MLSL), and GeoSurveys in 1987. 

MCSL continued to operate mainly as an engineering and geomatics firm serving the energy, transportation, and municipal markets throughout BC and in parts of Western Canada. MLSL operated mainly as a geomatics firm serving oil and gas clients in Alberta. MLSL changed its name to McElhanney Geomatics Engineering Ltd. (MGEL) in 2018. GeoSurveys closed in 1994.

Acquisition
McElhanney Ltd. was established in 2019, by an amalgamation between sister companies, McElhanney Geomatics Engineering Ltd. and McElhanney Consulting Services Ltd., which were separate companies since 1987.

References

Companies based in Vancouver
Construction and civil engineering companies of Canada
Construction and civil engineering companies established in 1910
Canadian companies established in 1910
Float-zone silicon. Float-zone silicon is very pure silicon obtained by vertical zone melting. The process was developed at Bell Labs by Henry Theuerer in 1955 as a modification of a method developed by William Gardner Pfann for germanium. In the vertical configuration molten silicon has sufficient surface tension to keep the charge from separating. The major advantages is crucibleless growth that prevents contamination of the silicon from the vessel itself and therefore an inherently high-purity alternative to boule crystals grown by the Czochralski method.

The concentrations of light impurities, such as carbon (C) and oxygen (O2) elements, are extremely low. Another light impurity, nitrogen (N2), helps to control microdefects and also brings about an improvement in the mechanical strength of the wafers, and is now being intentionally added during the growth stages.

The diameters of float-zone wafers are generally not greater than 200 mm due to the surface tension limitations during growth. A polycrystalline rod of ultrapure electronic-grade silicon is passed through an RF heating coil, which creates a localized molten zone from which the crystal ingot grows. A seed crystal is used at one end to start the growth. The whole process is carried out in an evacuated chamber or in an inert gas purge.

The molten zone carries the impurities away with it and hence reduces impurity concentration (most impurities are more soluble in the melt than the crystal). Specialized doping techniques like core doping, pill doping, gas doping and neutron transmutation doping are used to incorporate a uniform concentration of desirable impurity.

Float-zone silicon wafers may be irradiated by neutrons to turn it into a n-doped semiconductor.

Application
Float-zone silicon is typically used for power devices and detector applications, where high-resistivity is required. It is highly transparent to terahertz radiation, and is usually used to fabricate optical components, such as lenses and windows, for terahertz applications. It is also used in solar arrays of satellites as it has higher conversion efficiency.

See also
 Bridgman–Stockbarger method
 Micro-pulling-down
 Laser-heated pedestal growth

References

 Michael Riordan & Lillian Hoddeson (1997) Crystal Fire: the birth of the information age, page 230, W. W. Norton & Company  .

Industrial processes
Semiconductor growth
Silicon, Float-zone
Methods of crystal growth
TNTmips. TNTmips is a geospatial analysis system providing a fully featured GIS, RDBMS, and automated image processing system with CAD, TIN, surface modeling, map layout and innovative data publishing tools. TNTmips has a single integrated system with an identical interface, functionality, and geodata structure for use on Mac and Windows operating systems. The interface, database text content, messages, map production, and all other internal aspects of TNTmips have been localized for use in many languages, including, for example Arabic, Thai, and all romance languages. The professional version of TNTmips is in use in over 120 nations while the TNTmips Free version (restricted in project size) is used worldwide for educational, self learning, and small projects (e.g., archaeological sites, neighborhood planning, and precision farming).

History
TNTmips was initially branded MIPS from its creation in 1986 until 2022.

General information
TNTmips is a system for fully integrated GIS, CAD, with integrated geospatial database management.

License levels
 TNTmips Pro (professional license),
 TNTmips Basic (low cost license),
 TNTmips Free (freeware).

Special Academic License (SAL)
The TNT products include: TNTmips, TNTedit, TNTview, TNTatlas and TNTsdk. There is no distinction between TNTmips and TNT products with regards to license levels.
All TNT products are available for Windows and Macintosh computers in a growing number of international languages.

References

Footnotes

Sources

External links
 MicroImages
 GIS Team Germany Reseller for TNTproducts

GIS software
Remote sensing software
Journal of Artificial Intelligence Research. The Journal of Artificial Intelligence Research (JAIR) is an open access peer-reviewed scientific journal covering research in all areas of artificial intelligence.

History 
It was established in 1993 as one of the first scientific journals distributed online. Paper volumes are printed by the AAAI Press. The Journal for Artificial Intelligence Research (JAIR) is one of the premier publication venues in artificial intelligence. JAIR also stands out in that, since its launch in 1993, it has been 100% open-access and non-profit.

Content 
The Journal of Artificial Intelligence Research (JAIR) is dedicated to the rapid dissemination of important research results to the global artificial intelligence (AI) community. The journal's scope encompasses all areas of AI, including agents and multi-agent systems, automated reasoning, constraint processing and search, knowledge representation, machine learning, natural language, planning and scheduling, robotics and vision, and uncertainty in AI.

Abstracting and indexing 
The journal is abstracted and indexed by Inspec, Science Citation Index, and MathSciNet. According to the Journal Citation Reports, the journal has a 2019 impact factor of 2.441.

According to the SciMago Journal and Country Rank, the journal is ranked 8th among all open access computer science journals with an H-index of 112.

However, according to Google Scholar in 2021 it only has an h5-index of 38, which suggests some potential issues in measuring its impact.

References

External links
 

Open access journals
Academic journals established in 1993
English-language journals
Artificial intelligence journals
OpenSees. OpenSees (the Open System for Earthquake Engineering Simulation) is an object-oriented software framework created during the National Science Foundation-sponsored era (1997-2007) of the Pacific Earthquake Engineering Research
(PEER) Center. OpenSees allows users to create finite element applications for simulating the response of structural and geotechnical systems subjected to earthquakes. This framework was developed by Frank McKenna and Gregory L. Fenves with significant contributions from Michael H. Scott, Terje Haukaas, Armen Der Kiureghian, Remo M. de Souza, Filip C. Filippou, Silvia Mazzoni, and Boris Jeremic.  OpenSees is primarily written in C++ and uses several Fortran numerical libraries for linear equation solving.

Licensing
The license permits the use, reproduction, modification, and distribution by educational, research, and non-profit entities for non-commercial purposes. Use, reproduction, and modification by other entities is allowed for internal purposes, but these entities cannot redistribute the program or its derivatives.

Usage
Users of OpenSees create applications by writing scripts in either the Tcl or Python programming language.

OpenSees developers manage the source code at GitHub.

Acronym
The proper acronym capitalization for the "Open System for Earthquake Engineering Simulation" is OpenSees, as opposed to OpenSEES.  This reflects the same unconventional capitalization of Tcl.

History
Prior to taking on the name "OpenSees," the framework was simply called "G3" in reference to the name of the PEER research group tasked with simulation development.
The doctoral thesis of Frank McKenna on parallel object-oriented structural analysis formed the basis for "G3."

The current version as of March 2024 is 3.6.0.

References

External links
OpenSees Webpage
OpenSees Manual
OpenSeesPy PyPi page

Numerical software
Earthquake engineering
Finite element software for Linux
Aerolift. Aerolift was a South African airline based in Bryanston, Gauteng, Johannesburg, operating chartered passenger and cargo flights within Africa using Soviet-built aircraft.  Aerolift also offered aircraft lease services. The airline was launched in 2002 and shut down in 2009 following two fatal accidents that had occurred in the same year.

Fleet 
Upon closure, the Aerolift fleet included the following aircraft:

1 Antonov An-12
1 Antonov An-26
1 Antonov An-32
1 Antonov An-72
1 Antonov An-124
1 Ilyushin Il-76
1 Lockheed Tristar

Accidents and incidents

On 20 February 2009, an Aerolift Antonov An-12 crashed upon take-off at Luxor International Airport, Egypt due to an engine fire, killing all five crew members on board.
On March 9, 2009 Aerolift Ilyushin Il-76 S9-SAB crashed into Lake Victoria just after takeoff from Entebbe Airport, Uganda, killing all 11 people on board. Two of the engines had caught fire on take-off. The aircraft had been chartered by DynCorp on behalf of AMISOM. The accident was investigated by Uganda's Ministry of Transport, which concluded that all four engines were time-expired and that Aerolift's claim that maintenance had been performed which extended their service live and that the work had been certified could not be substantiated.

References 

Defunct airlines of South Africa
Defunct cargo airlines
Airlines established in 2002
Airlines disestablished in 2009
2002 establishments in South Africa
2009 disestablishments in South Africa
Cargo airlines of South Africa
Companies based in Johannesburg
DDX. DDX may refer to:

 , a common notation for the differential operator with respect to a variable x
 DD(X), former program name of a class of U.S. Navy destroyers
 Differential diagnosis (DDx or D/Dx), a systematic method used to identify unknowns
 Device Dependent X, graphics device drivers supporting 2D acceleration in the X.Org Server
 DDX (chemistry), a collective name for DDT and its breakdown products DDE and DDD

See also
 3DDX, a rhythm video game
 DXD (disambiguation)
Thermal adhesive. Thermal adhesive is a type of thermally conductive glue used for electronic components and heat sinks. It can be available as a paste (similar to thermal paste) or as a double-sided tape.

It is commonly used to bond integrated circuits to heatsinks where there are no other mounting mechanisms available.

The glue is typically a two-part epoxy resin (usually for paste products) or cyanoacrylate (for tapes). The thermally conductive material can vary including metals, metal oxides, silica or ceramic microspheres. The latter are found in products that have much higher dielectric strength, although this comes at the cost of lower thermal conductivity.

End-user modding heatsinks may be supplied with thermal adhesive attached (usually a piece of tape). For products sold through electronic components distributors this is rarely the case; the adhesives are sold separately to professionals.

See also 
 Computer cooling
 Hot-melt adhesive
 Phase-change material
 Thermally conductive pad
 Thermal paste
 List of thermal conductivities

References

Further reading 
 

Adhesives
Token passing. On a local area network, token passing is a channel access method where a packet called a token is passed between nodes to authorize that node to communicate. In contrast to polling access methods, there is no pre-defined "master" node. The most well-known examples are IBM Token Ring and ARCNET, but there were a range of others, including FDDI (Fiber Distributed Data Interface), which was popular in the early to mid 1990s.

Token passing schemes degrade deterministically under load, which is a key reason why they were popular for industrial control LANs such as MAP, (Manufacturing Automation Protocol). The advantage over contention based channel access (such as the CSMA/CD of early Ethernet), is that collisions are eliminated, and that the channel bandwidth can be fully utilized without idle time when demand is heavy. The disadvantage is that even when demand is light, a station wishing to transmit must wait for the token, increasing latency.

Some types of token passing schemes do not need to explicitly send a token between systems because the process of "passing the token" is implicit. An example is the channel access method used during "Contention Free Time Slots" in the ITU-T G.hn standard for high-speed local area networking using existing home wires (power lines, phone lines and coaxial cable).

See also
Cambridge Ring
HP Interface Loop (HP-IL)
Ring network

References

Channel access methods
Disequilibrium. Disequilibrium is the lack of or opposite of an equilibrium.

Economics
 lack of economic equilibrium
 General disequilibrium 
 Disequilibrium (economics)

Medicine
 Disequilibrium (medicine) (DES), a syndrome in cerebral palsy  
 lack of equilibrioception
 Dialysis disequilibrium syndrome

Political science
 Status-income disequilibrium

Population genetics
 Linkage disequilibrium, the non-random association of alleles at two or more loci, not necessarily on the same chromosome

Thermodynamics
 Disequilibrium (thermodynamics)
Hydrospring. A hydrospring or hydro-spring is a spring damped by hydraulic fluid (typically oil) being driven through holes in a piston, as the piston moves in response to a force. The spring is often made of rubber. Inside a rubber hydrospring there are hydraulic viscous damping systems which damp movement in all three directions but require very few parts. Even the slack adjustment may be integrated into the element.

Hydrosprings are used mainly as shock absorbers in applications such as damped suspension in railway bogies, bulldozer blade shock absorbers and as recoil absorbers for artillery.

See also
 Dashpot

References

 Army Dictionary - see hydrospring
 Army Dictionary - see recoil cylinder
 A railway hydrospring

Springs (mechanical)
Ball and beam. The ball and beam system consists of a long beam which can be tilted by a servo or electric motor together with a ball
rolling back and forth on top of the beam.
It is a popular textbook example in control theory.

The significance of the ball and beam system is that it is a simple system which is open-loop unstable.
Even if the beam is restricted to be very nearly horizontal, without active feedback, it will swing to one side or the
other, and the ball will roll off the end of the beam.  To stabilize the ball, a control system which
measures the position of the ball and adjusts the beam accordingly must be used.

In two dimensions, the ball and beam system becomes the ball and plate system, where a ball rolls on top of
a plate whose inclination can be adjusted by tilting it forwards, backwards, leftwards, or rightwards.

External links

 Ball and beam with various controls strategies
 Ball and beam 1: basics
 Ball and beam with comprehensive dynamics and movies

Control engineering