omniomni/omni-engineering huggingface dataset:
Height finder. A height finder is a ground-based aircraft altitude measuring device. Early height finders were optical range finder devices combined with simple mechanical computers, while later systems migrated to radar devices. The unique vertical oscillating motion of height finder radars led to them also being known as nodding radar. Devices combining both optics and radar were deployed by the U.S. Military.

Optical 
In World War II, a height finder was an optical rangefinder used to determine the altitude of an aircraft (actually the slant range from the emplacement which was combined with the angle of sight, in a mechanical computer, to produce altitude), used to direct anti-aircraft guns.  Examples of American and Japanese versions exist. In the Soviet Union it was usually combined with optical rangefinders.

Radar 
A height finder radar is a type of 2-dimensional radar that measures altitude of a target.

The operator slews the antenna toward a desired bearing, identifies a target echo at a desired range on the range height indicator display, then bisects the target with a cursor that is scaled to indicate the approximate altitude of the target.  Such systems often complement 2-dimensional radars which find distance and direction (search radar); thus using two 2-dimensional systems to obtain a 3-dimensional aerial picture.  Height finding radars of the 1960s and 70s were distinguished by their antenna being tall, but narrow. As beam shape is a function of antenna shape, the height finder beam was flat and wide horizontally (i.e., not very good at determining bearing to the target), but very thin vertically, allowing accurate measurement of elevation angle, thus altitude.

Modern 3D radar sets find both azimuth and elevation, making separate height finder radars largely obsolete.

See also 
 Radar
 Air Ministry Experimental Station

References

External links

A page about a type of height finders found in surface-to-air missile sites (German)

Radar
Electron-withdrawing group. An electron-withdrawing group (EWG) is a group or atom that has the ability to draw electron density toward itself and away from other adjacent atoms. This electron density transfer is often achieved by resonance or inductive effects. Electron-withdrawing groups have significant impacts on fundamental chemical processes such as acid-base reactions, redox potentials, and substitution reactions.

Consequences of EWGs

Effects on Bronsted acidity 
Electron-withdrawing groups exert an "inductive" or "electron-pulling" effect on covalent bonds. The strength of the electron-withdrawing group is inversely proportional to the pKa of the carboxylic acid.

The inductive effect is cumulative: trichloroacetic acid is 1000x stronger than chloroacetic acid.

The impact of the EWG on pKa decreases with distances from the carboxylic group.

For benzoic acids, the effect is quantified by the Hammett equation:

where
 = Reference constant
 = Substituent constant
 = Reaction rate constant

Effect on Lewis acidity
EWGs enhance the Lewis acidity, making compounds more reactive as Lewis acids. For example, fluorine is a stronger electron-withdrawing substituent than methyl, resulting in an increased Lewis acidity of boron trifluoride relative to trimethylborane. Electron-withdrawing groups also tend to reduce Lewis basicity.

Effect on a aromatic substitution reactions

Electrophilic aromatic substitution is famously affected by EWGs. The effect is transmitted by inductive and resonance effects. Benzene with an EWG typically undergoes electrophilic substitution at meta positions.  Overall the rates are diminished. thus EWGs are called deactivating.

When it comes to nucleophilic substitution reactions, electron-withdrawing groups are more prone to nucleophilic substitution. For example, chlorodinitrobenzene is far more susceptible to reactions displacing chloride compared to chlorobenzene.

Effects on redox potential
In the context of electron transfer, these groups enhance the oxidizing power tendency of the attached species. For example,  Tetracyanoethylene serves as an oxidant due to its attachment to four cyano substituents, which are electron-withdrawing groups.

Oxidants with EWGs are stronger than the parent compound.  Acetylferrocenium is 300 mV more oxidizing than ferrocene.

Comparison with electron-donating groups 
Electron-withdrawing groups are the opposite effect of electron-donating groups (EDGs). Both describe functional groups, however, electron-withdrawing groups pull electron density away from a molecule, whereas EDGs  push electron density onto a substituent.

See also
 Electron-donating group

References

Physical organic chemistry
Chemical bonding
HuCard. The  (Known as the TurboChip  in regions where the PC Engine was marketed as the TurboGrafx-16) is a ROM cartridge in the form of a card, designed by Hudson Soft for NEC's PC Engine and PC Engine SuperGrafx video game consoles, which were originally released in 1987 and 1989, respectively.

Development 

The HuCard is an evolution from an earlier Hudson Soft technology, the Bee Card, which it developed in the early 1980s as a distribution medium for MSX software; In July 1985, Hudson Soft approached and pitched Nintendo a new add-on for the Famicom that played games using their patented Bee Cards, which was experimented on the MSX computer. Nintendo liked this concept, as it had the ability to store full games and overwrite existing ones. However, as the technology for it was expensive, and that they would have to pay royalties for each card sold, Nintendo instead decided to pass on Hudson Soft's proposal. This eventually led to the partnership between Hudson Soft and NEC. The Bee Card is an EEPROM device that is slightly thinner than the HuCard. It has 32 connectors whereas the HuCard has 38.

Most video game cartridges have a large plastic housing to protect the PCB while providing enough space inside for radiant heat and, less often, a button cell. The PCB in a HuCard or Bee Card is protected by a rigid, glossy polymer that conducts heat; since the PC Engine and TurboGrafx-16 leave one side of the card partially exposed while inserted in the console, heat disperses with less obstruction.

Releases 

Video game developers made new releases on HuCard until December 1994, when 21 Emon: Mezase! Hotel Ō was released in Japan for the PC Engine. It was the last official release for the platform in any region.

Hudson Soft, NEC, and other vendors published seven HuCard games specifically for the PC Engine SuperGrafx. Hudson Soft called this enhanced medium the Super HuCard.

Atlantean, an independent game released on a HuCard, was made available in August 2014. Jessie Jaeger in Cleopatra's Curse is a new title in development with a planned release in 2022.

See also

References 

Computer-related introductions in 1987
Solid-state computer storage media
TurboGrafx-16
Video game distribution
Video game storage media
Molinology. Molinology (from Latin: molīna, mill; and Greek λόγος, study) is the study of mills and other similar devices which use energy for mechanical purposes such as grinding, fulling or sawing.

Mill technology
The term "Molinology" was coined in 1965 by the Portuguese industrial historian João Miguel dos Santos Simões. Mills make use of moving water or wind, or the strength of animal or human muscle to power machines for purposes such as hammering, grinding, pumping, sawing, pressing or fulling. Since the material resources and technology available to harness mill power have varied across societies and across time, different human societies developed different solutions to the problem. Thus molinology is a multidisciplinary area of study which reaches beyond mechanical analysis of the mills.

Cultural and scientific interest in molinology is maintained by The International Molinological Society (TIMS), a non-profit organisation which brings together around five hundred members worldwide. It was founded in 1973 after earlier international symposia in 1965 and 1969. The Society aims to retain the knowledge of those traditional engines which have been rendered obsolete by modern technical and economic trends.

See also

Further reading

External links
Official website of The International Molinological Society
The Society for the Preservation of Old Mills (SPOOM)
The Mills Archive

References

History of technology
EADS 3 Sigma. EADS 3 Sigma is the name since 2002 (when its majority was acquired by the European EADS Group) of the Greek 3 Sigma aerospace company. It was founded in 1987 with headquarters in Athens and production facilities in Chania, Crete. It has designed, produced and exported a variety of Unmanned Aerial Vehicles - including the Iris, Alkyon, Perseas (also available with single- and twin-jet engines), and 3 Sigma Nearchos types - as well as various electronics; its areas of research and development, in collaboration with Greek Universities, have included engine and remote control technologies.

EADS 3 Sigma announced in November 2012 that the company was in liquidation as it was no longer financially viable to continue its operations. A successor company, ALTUS LSA, was subsequently founded by former 3 Sigma executives.

External links/References 
L.S. Skartsis, "Greek Vehicle & Machine Manufacturers 1800 to present: A Pictorial History", Marathon (2012)  (eBook)
https://web.archive.org/web/20091212070405/http://www.eads-3sigma.gr/
Article about ALTUS LSA, successor company (in Greek)

Former Airbus subsidiaries and divisions
Aircraft manufacturers of Greece
Defence companies of Greece
Greek brands
Defunct manufacturing companies of Greece
Manufacturing companies based in Athens
EADS 3 Sigma Nearchos. The EADS 3 Sigma Nearchos is a medium distance reconnaissance unmanned aerial vehicle (UAV) introduced in 1996, one of several UAVs developed by the Greek 3 Sigma (since 2002 EADS 3 Sigma) aerospace company, in collaboration with Greek universities.

Uses

Military
 Battlefield surveillance
 Aerial reconnaissance
 Target acquisition
 Damage assessment
 ESM/ECM
 Communication data relay

Civilian
 Geological and maritime applications
 Traffic surveillance
 Localization of polluted areas and natural disaster areas
 Border and forestry patrolling
 Forest fire detection

Specifications (Nearchos)

Further development was terminated after the company went out of business in 2012.

See also

External links/References 
Company website (archived)

Airbus Defence and Space aircraft
Unmanned military aircraft of Greece
Satellite digital imaging system. The satellite digital imaging system (SDIS) is a simple system composed of commercial off-the-shelf (COTS) hardware and custom integration software, which allows the operator to transmit digital photos from an aircraft in flight to a ground station.  It is currently used by the United States Civil Air Patrol (CAP) for domestic search and rescue operations and commercial photography.

Components
 Nikon D100 digital SLR camera.
 Panasonic Toughbook laptop computer with SDIS software installed.
 Satellite telephone.

The SDIS consists essentially of connecting these three devices to one another.  No hardware is physically installed in the aircraft.

Operation
Prior to takeoff, the operator connects the laptop to the web mission information reporting system (WMIRS) and obtains a mission identifier.  During flight, photos are downloaded to the laptop computer and e-mailed to the customer or CAP base using the satellite phone.  Images are also captured to a memory card in the digital camera, and may be edited or uploaded to the WMIRS after landing.

The satellite digital imaging system (SDIS) was demonstrated successfully in the search and recovery efforts following hurricanes Katrina and Rita in 2005.

Advantages/disadvantages
Advantages
Near real-time
Low cost
Multi-facet use

Disadvantages
Unreliable (If high cloud-cover is present satellite acquisition is difficult)
Slow upload (due to sat. feed)

External links

Digital Photography

Digital photography
Jet Propulsion Laboratory Display Information System. The Jet Propulsion Laboratory Display Information System (or JPLDIS) is a file management program written in FORTRAN.

JPLDIS is important because it was the inspiration and precursor to dBASE, arguably one of the most influential DBMS programs for early microcomputers.

History 
In the late 1960s, Fred Thompson at the Jet Propulsion Laboratory (JPL) of the California Institute of Technology (Caltech) was using a Tymshare product named RETRIEVE to manage a database of electronic calculators. In 1971 Fred collaborated with Jack Hatfield, a programmer at JPL, to write an enhanced version of RETRIEVE which became the JPLDIS project.

JPLDIS evolved into a file management program written in FORTRAN, running on a UNIVAC 1108 mainframe. Hatfield published two papers entitled "Jet Propulsion Laboratory Data Information System (JPLDIS)". The first paper was presented to the Univac Users Group in Dallas, TX (Feb. 1973) and the second paper was presented to the National Science Foundation conference on Data Storage and Retrieval Methods at the University of Missouri in Columbia, Missouri (July 1973). Hatfield left JPL in 1974 and the JPLDIS project was assigned to Jeb Long, another programmer at JPL, who added many advanced features plus a programming language. 

In 1978, while at JPL, Wayne Ratliff wrote a database program in assembly language for CP/M based microcomputers to help him win the football pool at the office. He based it on Jeb Long's JPLDIS and called it Vulcan, after Mr. Spock of Star Trek. In late 1980, George Tate, of Ashton-Tate, entered into a marketing agreement with Wayne Ratliff. Vulcan was renamed to dBase, the price was raised from $50 to $695, and the software quickly became a huge success.

When a number of "clones" of dBase appeared in the 1990s, Ashton-Tate sued one of them, FoxPro, over copyrights. On December 11, 1990, Judge Hatter issued an order invalidating Ashton-Tate's copyrights in its own dBASE products. That ruling was based on a legal doctrine known as "unclean hands". Judge Hatter explained that Ashton-Tate knew that the dBase program development was based on JPLDIS, and that fact was kept hidden from the Copyright Office.

See also 
dBase
Vulcan (programming language)

References 

Computer-related introductions in 1973
NASA online
Proprietary database management systems
Wayne Ratliff. Cecil Wayne Ratliff (born 1946) wrote the database program Vulcan. Raised in Germany and the US, he now resides in the Los Angeles area.

Biography
Ratliff was born in 1946 in Trenton, Ohio, USA. From 1969 to 1982 he worked for the Martin Marietta Corporation in a progression of engineering and managerial positions. He was a member of the NASA Viking program flight team when the Viking spacecraft landed on Mars in 1976, and wrote the data management system, MFILE, for the Viking lander support software.

In 1978 Ratliff wrote Vulcan, a database application, to help him make picks for football pools. Written in Intel 8080 assembly language, it ran on the CP/M operating system and was modeled on JPLDIS. After selling Vulcan by himself from 1979 to 1980, he licensed the software, renamed dBASE, to Ashton-Tate. In 1982 Ratliff left JPL and joined Ashton-Tate as vice president of new technology. (He never used the software for its original purpose; in 1984 Ratliff confessed that dBASE had made him so busy that "I've only had time to watch two or three football games".)

Ratliff was the project manager for dBASE III, as well as designer and lead programmer. From 1987 to 1988 Ratliff wrote Emerald Bay, a client/server database manager. Currently retired, Ratliff spends time sailing and studying mathematics. He has worked on computer systems for use in competitive sailboat racing.

References

1946 births
Living people
People from Trenton, Ohio
Martin Marietta people
Double heterostructure. A double heterostructure, sometimes called double heterojunction, is formed when two semiconductor materials are grown into a "sandwich". One material (such as AlGaAs) is used for the outer layers (or cladding), and another of smaller band gap (such as GaAs) is used for the inner layer. In this example, there are two AlGaAs-GaAs junctions (or boundaries), one at each side of the inner layer. There must be two boundaries for the device to be a double heterostructure. If there was only one side of cladding material, the device would be a simple, or single, heterostructure.

The double heterostructure is a very useful structure in optoelectronic devices and has interesting electronic properties. If one of the cladding layers is p-doped, the other cladding layer n-doped and the smaller energy gap semiconductor material undoped, a p-i-n structure is formed. When a current is applied to the ends of the pin structure, electrons and holes are injected into the heterostructure. The smaller energy gap material forms energy discontinuities at the boundaries, confining the electrons and holes to the smaller energy gap semiconductor. The electrons and holes recombine in the intrinsic semiconductor emitting photons. If the width of the intrinsic region is reduced to the order of the de Broglie wavelength, the energies in the intrinsic region no longer become continuous but become discrete. (Actually, they are not continuous but the energy levels are very close together so we think of them as being continuous.) In this situation the double heterostructure becomes a quantum well.

References

Semiconductor structures
HP-75. The HP-75C and HP-75D were hand-held computers programmable in BASIC, made by Hewlett-Packard from 1982 to 1986.

The HP-75 had a single-line liquid crystal display, 48 KiB system ROM and 16 KiB RAM, a comparatively large keyboard (albeit without a separate numeric pad), a manually operated magnetic card reader (2×650 bytes per card), 4 ports for memory expansion (1 for RAM and 3 for ROM modules), and an HP-IL interface that could be used to connect printers, storage and electronic test equipment.  The BASIC interpreter also acted as a primitive operating system, providing file handling capabilities for program storage using RAM, cards, or cassettes/diskettes (via HP-IL).

Other features included a text editor as well as an appointment reminder with alarms, similar to functions of modern PDAs.

The HP-75D (1984–1986) added a port for a bar code wand, often used for inventory control tasks.

The HP-75 was comparatively expensive with an MSRP of $995 ($2,014 in 2005) for the 75C or $1095 ($2,058 in 2005) for the 75D, making it less popular than the cheaper successor model, the HP-71B.

The HP-75C has a KANGAROO printed on its PCB, as its codename (see link for picture).

HP-75D codename's is MERLIN.

Reception
BYTE praised the flexibility of the appointment scheduler, which the review noted could comprise part of a real-time control system because of its ability to execute BASIC programs. It concluded that the computer "is a well-integrated and powerful machine ... if you are interested in ... a very portable computer with powerful real-time scheduling capabilities, you should look closely at the HP-75".

References

External links 

 HP-75 at the MoHPC
 HP Journal, June 1983 Article about the HP-75C design, the IL interface and the card reader
Some nice internal views at MyCalcDB (see the Kangaroo on the PCB)

75C D
Pocket computers
Products introduced in 1982
GNU Binutils. The GNU Binary Utilities, or , is a collection of programming tools maintained by the GNU Project for working with executable code including assembly, linking and many other development operations.

The tools are originally from Cygnus Solutions.

The tools are typically used along with other GNU tools such as GNU Compiler Collection, and the GNU Debugger.

Tools

The tools include:

elfutils
Ulrich Drepper wrote , to partially replace GNU Binutils, purely for Linux and with support only for ELF and DWARF. It distributes three libraries with it for programmatic access.

See also

References

External links
 
 The ELF Tool Chain Project : the BSD license similar project (mirror)

Programming tools
GNU Project software
Vitaly Efimov. Vitaly N. Efimov (Russian: Вита́лий Никола́евич Ефи́мов) is a Russian theoretical physicist. He proposed the existence of a novel and exotic state of matter now dubbed the Efimov State as a researcher in A. F. Ioffe Physico-Technical Institute, USSR Academy of Sciences, Leningrad, USSR in his 1970 paper "Energy levels arising from resonant two-body forces in a three-body system". It was announced in 2006 that the existence of this state of matter had been confirmed.

He is now an affiliate professor of physics at the University of Washington.

In 2018 he has been selected as the winner of the Inaugural Fadeev Medal.

References

External links 
March 15, 2006: Atoms in new state of matter behave like Three Musketeers: All for one, one for all
May 27, 2014: Physicists Prove Surprising Rule of Threes

1938 births
Living people
Russian physicists
Russian theoretical physicists
Fellows of the American Physical Society
Paul W. K. Rothemund. Paul Wilhelm Karl Rothemund is a research professor at the Computation and Neural Systems department at Caltech. He has become known in the fields of DNA nanotechnology and synthetic biology for his pioneering work with DNA origami.  He shared both categories of the 2006 Feynman Prize in Nanotechnology with Erik Winfree for their work in creating DNA nanotubes, algorithmic molecular self-assembly of DNA tile structures, and their theoretical work on DNA computing.  Rothemund is also a 2007 recipient of the MacArthur Fellowship.

Life
Rothemund graduated from Laconia High School, New Hampshire, in 1990. He was the team captain of the championship Laconia team for the television quiz show Granite State Challenge. After graduating, Rothemund studied as an undergraduate at Caltech from 1990–1994, where he was a resident and member of Ricketts House.  He attained his Ph.D. from the University of Southern California in 2001.

As a research fellow at Caltech, Rothemund has developed a technique to manipulate and fold strands of DNA known as DNA origami. 
Eventually, Rothemund hopes that self-assembly techniques could be used to create a "programming language for molecules, just as we have programming languages for computers."  
His work on large-scale sculptures of his DNA origami was exhibited at the Museum of Modern Art in New York from February 24 to May 12, 2008.

His grandfather, Paul Rothemund, was a chemist as well.

References

External links
 Paul Rothemund's home page
 March 2006 Nature paper on DNA origami
 March 2007 TED Talk
 September 2008 TED Talk

Living people
Year of birth missing (living people)
MacArthur Fellows
California Institute of Technology faculty
DNA nanotechnology people
California Institute of Technology alumni
California Institute of Technology fellows
University of Southern California alumni
Volvo Philip. The Volvo Philip was a concept car built by Volvo in 1952. It was designed especially for the United States market, and so was fitted with a prototype V8 engine called the B8B, which produced  at 4000 rpm along with whitewall tires and a hint of tailfins.

The design was inspired by American cars and was similar to the 1951 Kaiser. The designer was Jan Wilsgaard, who also designed the Volvo Amazon. However, it was cancelled by the board and never reached production, with only one car being made. That car was used for several years by the board at Bolinder-Munktell in Eskilstuna and is now preserved at the Volvo Museum in Gothenburg.

This vehicle was hand built under extreme secrecy and was subjected to thorough testing. However, the V8 engine entered production in 1956 and was used for a truck, the Volvo Snabbe, as well as for boats. It was known for being strong and reliable but also for high fuel consumption. Production of the engine had ceased by 1973.

Philip