omniomni/omni-engineering huggingface dataset:
Polymeric liquid crystal. Polymeric liquid crystals are similar to monomeric liquid crystals used in displays. Both have dielectric anitroscopy, or the ability to change directions and absorb or transmit light depending on electric fields. Polymeric liquid crystals form long head-to-tail or side chain polymers, which are woven in thick mats and therefore have high viscosities. The high viscosities allow the polymeric liquid crystals to be used in complex structures, but they are harder to align, limiting their usefulness.  The polymerics align in microdomains facing all different directions, which ruins the optical effect.  One solution to this is to mix in a small amount of photo-curing polymer, which when spin-coated onto a surface can be hardened. Basically, the polymeric liquid crystal and photocurer are aligned in one direction, and then the photo curer is cured, "freezing" the polymeric in one direction.

References 

Liquid crystals
Extinction (optical mineralogy). Extinction is a term used in optical mineralogy and petrology, which describes when cross-polarized light dims, as viewed through a thin section of a mineral in a petrographic microscope.  Isotropic minerals, opaque (metallic) minerals, and amorphous materials (glass) do not allow light transmission under cross-polarized light (i.e. constant extinction). Anisotropic minerals specifically will show one extinction for each 90 degrees of stage rotation.

The extinction angle is the measure between the cleavage direction or habit of a mineral and the extinction.  To find this, simply line up the cleavage lines/long direction with one of the crosshairs in the microscope, and turn the mineral until the extinction occurs.  The number of degrees the stage was rotated is the extinction angle, between 0-89 degrees.  90 degrees would be considered zero degrees, and is known as parallel extinction.  Inclined extinction is a measured angle between 1-89 degrees.  Minerals with two cleavages can have two extinction angles, with symmetrical extinction occurring when minerals have multiple angles that are the same.  Minerals that have no cleavage or elongation can not have an extinction angle.

Minerals with undulose extinction, solid solution/zonation, or other factors (e.g. bird's eye extinction in mica) that may inhibit this measure and may be more difficult to use.

References

Mineralogy concepts
Optical mineralogy
Equivalent dumping coefficient. An equivalent dumping coefficient is a mathematical coefficient used in the calculation of the energy dispersed when a structure moves. As a civil engineering term, it defines the percent of a cycle of oscillation that is absorbed (converted to heat by friction) for the structure or sub-structure under analysis. Usually it is assumed that the equivalent dumping coefficient is linear, which is to say invariant compare to oscillatory amplitude. Modern seismic studies have shown this not to be a satisfactory assumption for larger civic structures, and have developed sophisticated amplitude and frequency based functions for equivalent dumping coefficient.

When a building moves, the materials it is made from absorb a fraction of the kinetic energy (this is especially true of concrete) due primarily to friction and to viscous or elastomeric resistance which convert motion or kinetic energy to heat.

References 

Energy (physics)
IACS. IACS may refer to:

 Indian Association for the Cultivation of Science
 Industrial Automation and Control Systems are also referred to as Industrial control systems
 Innovation Academy Charter School
 Integrated Administration and Control System
 International Annealed Copper Standard, a unit of electrical conductivity
 International Association of Classification Societies
 International Association of Cryospheric Sciences
 Inter-Asia Cultural Studies, a quarterly peer-reviewed academic journal
Technora. Technora is an aramid that is useful for a variety of applications that require high strength or chemical resistance. It is a brand name of the company Teijin Aramid.

Technora was used on January 25, 2004 to suspend the NASA Mars rover Opportunity from its parachute during descent.

It was also later used by NASA as one of the materials, combined with nylon and Kevlar, making up the parachute that was used to perform a braking manoeuvre during atmospheric entry of the rover Perseverance that landed on Mars on February 18, 2021.

Production
Technora is produced by condensation polymerization of terephthaloyl chloride (TCl) with a mixture of p-phenylenediamine (PPD) and 3,4'-diaminodiphenylether (3,4'-ODA). The polymer is closely related to Teijin Aramids's Twaron or DuPont's Kevlar. Technora is derived from two different diamines, 3,4'-ODA and PPD, whereas Twaron is derived from PPD alone. Because only one amide solvent is used in this very straightforward procedure, spinning can be completed immediately after polymer synthesis.

Physical properties 

Technora has a better strength to weight ratio than steel. Technora also has fire resistant properties which can be beneficial.

Major industrial uses

Automotive and other industries:
 Turbo hoses
 high pressure hoses
 Timing and V-belts
 mechanical rubber goods reinforcement
 Linear tension
 Optical fiber cables (OFC)
 Ram air parachute suspension lines
 ropes, wire ropes and cables
 Umbilical cables
 Electrical mechanical cable (EMC)
 Windsurfing sails
 Hangglider sails
 Drumheads
 Personal protective equipment
 Poi (performance art)

See also
 Vectran

References

Synthetic fibers
Materials
Organic polymers
Brand name materials
Cables
Robotron Group. Robotron Pty. Ltd. is an Australian research & development and manufacturing company of various specialty high-technology equipment. The company was founded in 1983 by Czech-born engineer Milan Hudecek. Its products include assistive technology equipment for the blind, such as reading machines, navigational and word-processing tools.

Hudecek's inspirational meetings with executives of various blind support and consumer organizations, discussing development of the Robotron equipment, for example, the Eureka A4 computers are described in various sources such as The Braille Monitor. The company also pioneered the development of speech synthesis products for non-European languages, for example Thai language 'Aria' computer.

The Robotron Rainbow and TR320 are reading machines for the blind.

In 1989, the company won the Australian Export Award.

In 1990, the company was awarded the annual Canadian Winston Gordon Award of Excellence in Accessible Technology in the field of blindness and visual impairment for their Eureka A4 device. The award "recognizes an individual or group who has made significant technological advances benefiting people with sight loss." The Eureka A4 attached to an early 1990s PC "to utilise screen orientated programs. It had sockets for telephone lines, a Braille keyboard, an inbuilt disk drive, speed and volume controls as well as outlets for data ports and headphones."

Stevie Wonder and Ray Charles both used Robotron equipment.

In 1991 the company founded a subsidiary called Rosetta Laboratories Pty. Ltd. (later renamed to Radixon Group Pty. Ltd.) to concentrate on development and marketing of specialty PC peripherals. One of its first products was the WiNRADiO PC card which provided the initial impetus for the development of the entire WiNRADiO range of PC-based radio receivers and accessories.

References

External links

 Robotron radio technology website
 Robotron assistive technology website

Electronics companies of Australia
Assistive technology
Australian companies established in 1983
Technology companies established in 1983
Gupta Technologies. Gupta Technologies, LLC  was a software development company based in Roseville, Placer County, California.  It was later renamed to Centura Software in the late 1990s and then to Halo Technology Holdings, Inc in 2005. It was acquired by Unify Corporation in 2006.

Its principal products are the SQL relational database management system SQLBase, a mobile HTML5 enterprise development system called TD Mobile and a rapid application development system called Team Developer (also known as SQLWindows).  The company is considered as the provider of the first client/server relational database software that would run on personal computers (PC), rather than mini computers.

Company history 

The company was founded in 1984 by Umang Gupta, a former vice president at Oracle Corporation. Gupta's first product was SQLBase, followed by SQLWindows, which combined SQLBase with a graphical user interface and programming language for creating business applications. SQLWindows was one of the first GUI development tools for Microsoft Windows.  The company went public in 1993 (NASDAQ: GPTA).

The name of the company was changed to Centura Software in the late 1990s. In February 2001 Centura was taken over by the Platinum Equity investment company. Centura Software filed for Chapter 11 Bankruptcy in August 2001, and the United States Securities and Exchange Commission revoked the registration of Centura's common stock in December 2004. After the bankruptcy, some assets were kept by a reborn Gupta Technologies LLC. 

In January 2005 Gupta Technologies, LLC was bought by another investor, Warp Technology Holdings, Inc. In May 2005 the company changed its name to Halo Technology Holdings, Inc. In September 2006 the company was acquired by Unify Corporation. In June 2010 Unify announced its merger with Daegis, a US company that provides software for electronic discovery in litigation matters.

In November 2012 the Unify database and development tools division was renamed back to Gupta Technologies.

In 2015 Gupta was acquired by OpenText.

References

External links
 Unify renamed to Gupta Technologies press release
 Umang Gupta as Keynote Speaker at Velocity  a Web Conference
 OpenText Gupta Technologies Website (including links to product documentation)
 Order suspending trade in Gupta stock
 Large collection of Team Developer samples
 Dedicated WIKI on Team Developer and related products
 Community forum for Q & A on Team Developer and related products

Software companies based in California
Companies based in Roseville, California
Software companies established in 1984
1984 establishments in California
American companies established in 1984
Defunct software companies of the United States
Europa Aircraft. Europa Aircraft is a British kitplane manufacturer that produces the Europa XS.

The company was established to produce a small kit-built low-wing aircraft for personal use within Europe, with these design goals: high speed, low cost, able to be built and stored at home, easily transportable, using Mogas fuel, able to be rigged for flight in under five minutes, carrying two people in comfort, providing sufficient baggage for extended touring. Apart from "low cost", these design parameters were largely met.

History

The original Europa, (the "Classic"), was designed by Ivan Shaw (born 1945) and the prototype, G-YURO, first flew in February 1992. Production of kit components was established at the company's factory in Kirkbymoorside, North Yorkshire.

In the early 1990s the company won a £100,000 grant from the UK Department of Trade and Industry in recognition of its technical achievements. Europa Aircraft has grown to be one of the most successful British kit plane suppliers, with over 700 Europas flying in 33 countries. The Europa XS was named as one of the UK's Millennium Products by the then Prime Minister Tony Blair, and described by Pilot magazine as "the most significant light plane of the decade".

Ivan Shaw left Europa to develop the Europa-derivative Liberty XL2 production aircraft at a new company, Liberty Aerospace, in Melbourne, Florida, United States. After Shaw left, the firm faced considerable difficulties; but in September 2008, company fortunes improved as Europa Aircraft was acquired by British company, Swift Technology Group.

Europa Aircraft has existed under several company names, and the current name is Europa Aircraft (2004) Ltd. The manufacturing of the Europa range of aircraft is carried out by a sister company, Aviation and Marine Engineering Ltd.  Other companies within the Group include Swift Aircraft, Swift TG Maintenance, Swift TG Solutions and Aviation, Swift TG Energy and TWF Solutions.

In 2020, Europa Aircraft announced the launch of a new kit aircraft design, the Europa Elite. The design will fit the into the EASA CS-VLA category and will be of all composite construction, with two seats in side-by-side configuration.

References

External links

Europa Aircraft
Aviation Marine and Engineering Ltd
Swift Technology Group

Aircraft manufacturers of the United Kingdom
Companies established in 1987
NONMEM. NONMEM is a non-linear mixed-effects modeling software package developed by Stuart L. Beal and Lewis B. Sheiner in the late 1970s at University of California, San Francisco, and expanded by Robert Bauer at Icon PLC. Its name is an acronym for nonlinear mixed effects modeling but it is especially powerful in the context of population pharmacokinetics, pharmacometrics, and PK/PD models. 
NONMEM models are written in NMTRAN, a dedicated model specification language that is translated into FORTRAN, compiled on the fly and executed by a command-line script. Results are presented as text output files including tables.  There are multiple interfaces to assist modelers with housekeeping of files, tracking of model development, goodness-of-fit evaluations and graphical output, such as PsN and xpose and Wings for NONMEM. Current version for NONMEM is 7.5.

Model estimation 
NONMEM estimates its models according to principles of maximum likelihood estimation. nonlinear mixed-effects model generally do not have close-formed solutions, and therefore specific estimation methods are applied, such as linearization methods as first-order (FO), first-order conditional (FOCE) or the laplacian (LAPL), approximation methods such as iterative-two stage (ITS), importance sampling (IMP), stochastic approximation estimation (SAEM) or direct sampling.

References

External links
Product site
NONMEM UsersNet Archive

Numerical software
Pharmacodynamics
Pharmacokinetics
2N3904. The 2N3904 is a common NPN bipolar junction transistor used for general-purpose low-power amplifying or switching applications.  It is designed for low current and power, medium voltage, and can operate at moderately high speeds.  It is complementary to the 2N3906 PNP transistor. Both types were registered by Motorola Semiconductor in the mid-1960s.

Device packaging and specifications
The construction of the 2N3904 and 2N3906 in the 1960s represented a significant performance and cost improvement, with the plastic TO-92 case replacing metal cans. This transistor is a low-cost device, widely available and sufficiently robust to be of use by experimenters and electronics hobbyists. When looking at the flat side with the leads pointed downward, the three wires emerging from the bottom are connected to, from left to right, the emitter, the base and the collector. Some manufacturers mark "EBC" on the molded part, but all are required to have those connections for a part which is a "2N3904".

It is a 200 mA, 40 V, 625 mW transistor with a transition frequency of 300 MHz, with a minimum beta, or current gain, of 100 at a collector current of 10 mA.

Related parts
Electrically similar devices, such as the MMBT3904, are available in a variety of small through-hole and surface-mount packages, including TO-92, SOT-23, and SOT-223, with package-dependent thermal ratings from 625 milliwatts to 1 watt.

The complementary PNP transistor is 2N3906.

Part numbers

The 2N3904 (NPN) and 2N3906 (PNP) are complementary transistor pairs.  These transistors are available in package styles TO-92, SOT23, SOT223 with different prefixes.

See also
 2N2222, 2N2907
 2N3055
 BC108
 BC548
 KT315

References

Further reading

Historical Databooks
 Small-Signal Transistor Data Book, 1386 pages, 1984, Motorola.
 Transistor and Diode Data Book, 1236 pages, 1973, Texas Instruments.

JEDEC standards
Commercial transistors
Bipolar transistors
2N3906. The 2N3906 is a commonly used PNP bipolar junction transistor intended for general purpose low-power amplifying or switching applications. It is designed for low electric current and power and medium voltage, and can operate at moderately high speeds. It is complementary to the 2N3904 NPN transistor. Both types were registered by Motorola Semiconductor in the mid-1960s.

Device packaging and specifications
The 2N3906 is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the case are, from left to right, the emitter, base, and collector leads.

The 2N3906 is specified by a collector current of 200 mA, collector-base and collector-emitter voltages of 40 V, for power dissipation of 300 mW. Its transition frequency Ft is 250 MHz, with a beta of at least 100.

Part numbers
The 2N3904 (NPN) and 2N3906 (PNP) are complementary transistor pairs.  These transistors are available in package styles TO-92, SOT23, SOT223 with different prefixes.

See also
 2N2222, 2N2907
 2N3055
 BC108
 BC548
 KT315

References

Further reading
 Small-Signal Semiconductors Data Book, 1218 pages, 1987, Motorola.
 Transistor and Diode Data Book, 1236 pages, 1973, Texas Instruments.

External links

JEDEC standards
Commercial transistors
Bipolar transistors
I-Chen Wu. I-Chen Wu () is a professor at Department of Computer Science, National Chiao Tung University. He received his B.S. in Electronic Engineering from National Taiwan University (NTU), M.S. in computer science from NTU, and Ph.D. in computer science from Carnegie-Mellon University, in 1982, 1984 and 1993, respectively. 

Wu invented a new game, named Connect6, a variation of the five-in-a-row game, and presented this game in the 11th Advances in Computer Games Conference (ACG'11) in 2005. The game-tree complexity of this game is quite high, close to Chinese Chess. Since presented in 2005, Connect6 has been a tournament item in Computer Olympiad. He wrote a program, named NCTU6, and won the gold in the tournament in 2006. Up to date, there have been at least four game websites supporting this game, at least 10 web forums for this game (in Traditional Chinese, Simplified Chinese, English, Spanish and multi-lingual), hundreds of thousands games played over the Internet, several Josekis (opening moves) and Tsumegos (like puzzles) developed, and one human Connect6 open tournament held in Summer 2006.

Wu also developed a game platform over Internet and actively participated in software development leading a team to major software components and framework in both clients and servers. In the client side, the team led by him developed a portable AWT/Swing architecture for Java game development, which has been used in some game companies including Sina Inc., Hinet, and ThinkNewIdea Inc., in Taiwan.

References

External links
Homepage of I-Chen Wu
Homepage of Connect6
Chess Programming Kiwi -- I-Chen Wu

Academic staff of the National Chiao Tung University
Affiliated Senior High School of National Taiwan Normal University alumni
Artificial intelligence researchers
Carnegie Mellon University alumni
Living people
National Taiwan University alumni
Taiwanese computer scientists
Year of birth missing (living people)
CPESC. Certified Professional in Erosion and Sediment Control (CPESC) is a qualification indicating the holder has educational training, expertise and experience in controlling erosion and sedimentation, and met certification standards.

Eligibility requirements 
 Each applicant must successfully pass a written examination designed to determine proficiency in the principles, practices, and legislation of erosion and sediment control. Applicants must also meet one of the following requirements:
 Earn a BS degree or higher plus three years of professional level experience in the soil erosion and sediment control profession
 Complete seven years or more of professional level experience in the erosion and sediment control profession.
 Through the professional experience profile, references, and written exam, the applicant must demonstrate an ability to observe, evaluate, and synthesize information; to consider alternatives; and to propose appropriate recommendations in a clear, logical manner.
 International applicants must provide documentation to assure that educational degrees obtained and work experience are comparable to the requirements described above.

Professional titles and certifications
Burt Kaliski. Burton S. "Burt" Kaliski, Jr. is a cryptographer, who is currently the chief technology officer (CTO) and senior vice president at Verisign. Before joining Verisign in 2011, he was the founding director of the EMC Innovation Network at EMC Corporation since its 2006 acquisition of RSA Security where he was Chief Scientist for RSA Laboratories. His notable work includes the development of such public key cryptography standards as PKCS and IEEE P1363, the extension of linear cryptanalysis to use multiple approximations, and the design of the block cipher Crab.

Kaliski received his B.S., M.S., and Ph.D. degrees in Computer Science from MIT, where his research was on cryptography. He was a visiting assistant professor of computer engineering at Rochester Institute of Technology before joining RSA Security.

He was also a guest professor and member of the international advisory board of Peking University,  School of Software and Microelectronics.

References

External links
 Bio: Burt Kaliski, The New Face of Technology Symposium, Georgia Tech College of Computing.
 Profile at the AMS-SIAM Mathematics Careers Bulletin Board (archived 2009)

Living people
Public-key cryptographers
American cryptographers
Computer security academics
MIT School of Engineering alumni
American chief technology officers
Year of birth missing (living people)
Environmental testing. Environmental testing is the measurement of the performance of equipment under specified environmental conditions. This can include the following:

 High and low extreme temperatures
 Temperature cycling
 Sand and dust exposure
 Salt spray
 High and low humidity
 Wet environments
 Deep water submersion
 Corrosive material exposure
 Algae and microbial exposure
 Shock and vibrations, including gun fire
 High and low pressure
 Pressure cycling
 Electromagnetic interference

Such tests are most commonly performed on equipment used in military, maritime, aeronautical and space applications.

Standards 
Environmental test standards include:
 MIL-STD-810
 MIL-HDBK-2036
 IEC 60068
 IEC 60945
 RTCA DO-160
 MIL-STD-461

See also
Environmental stress screening
Environmental test chambers
Direct Field Acoustic Testing
Technischer Überwachungsverein

References

External links

 
Testing
Reliability engineering
Wesley Vale pulp mill. The Wesley Vale pulp mill was a planned kraft process pulp mill, to be built near Wesley Vale and Devonport Airport in northern Tasmania in the late 1980s. The claim that waste would have been generated by the mill and present a threat to Tasmania's World Heritage listed forests became a significant environmental and political issue at the state and federal levels and construction of the mill was eventually canceled by its foreign-owned backers Noranda and North Ltd.

See also
Woodchipping
Papermaking
Christine Milne, a notable opponent of the mill

References
Department of Transport and Regional Services. 2003. Cradle Coast Region Tasmania, Chapter 5 - Environment.

Further reading
 (1988) Export pulp mill project, Wesley Vale Tasmania : environmental impact statement October 1988. Proponents: North Broken Hill Ltd, Noranda Forest St. Leonards, N.S.W. Sinclair Knight & Partners.
 Tasmania. Dept. of the Environment.(1989) Assessment report on the export pulp mill project, Wesley Vale Tasmania, environmental impact statement Hobart, Dept. of the Environment, Tasmania.
Latrobe Council