omniomni/omni-engineering huggingface dataset:
Per Georg Scheutz. Pehr (Per) Georg Scheutz (23 September 1785 – 22 May 1873) was a Swedish lawyer, translator, and inventor, who is now best known for his pioneering work in computer technology.

Life
Scheutz studied law at Lund University, graduating in 1805. He then worked as a legal expert and translator (he translated several works of William Shakespeare and Sir Walter Scott) before turning predominantly to liberal politics and mechanical engineering.

He is most known for his inventions; the best known of these is the Scheutzian calculation engine, invented in 1837 and finalized in 1843. This machine, which he constructed with his son Edvard Scheutz, was based on Charles Babbage's difference engine. In 1851 they obtained funds from government to build an improved model, which was created in 1853 (was roughly the size of a piano), and subsequently demonstrated at the World's Fair in Paris, 1855. The machine was then sold in 1856 to the Dudley Observatory in Albany, New York. In 1857 British government ordered another model, which was built by Donkin's company in 1859.

The devices were used for creating logarithmic tables.

While the machine was not perfect and could not produce complete tables, Martin Wiberg reworked the construction from the ground up and in 1875 created a compact device which would print complete tables.

Scheutz was elected a member of the Royal Swedish Academy of Sciences in 1856.

See also
Difference engine
Martin Wiberg
Timeline of computing hardware before 1950

References

Further reading

 Mario G. Losano (ed.), Scheutz: La macchina alle differenze. Un secolo di calcolo automatico, Etas Libri, Milano 1974, pp. 164.

1785 births
1873 deaths
19th-century Swedish inventors
19th-century Swedish businesspeople
19th-century Swedish lawyers
People connected to Lund University
Members of the Royal Swedish Academy of Sciences
Depolarization ratio. In Raman spectroscopy, the depolarization ratio is the intensity ratio between the perpendicular component and the parallel component of Raman scattered light.

Early work in this field was carried out by George Placzek, who developed the theoretical treatment of bond polarizability.

The Raman scattered light is emitted by the stimulation of the electric field of the incident light. Therefore, the direction of the vibration of the electric field, or polarization direction, of the scattered light might be expected to be the same as that of the incident light. In reality, however, some fraction of the Raman scattered light has a polarization direction that is perpendicular to that of the incident light. This component is called the . Naturally, the component of the Raman scattered light whose polarization direction is parallel to that of the incident light is called the , and the Raman scattered light consists of the parallel component and the perpendicular component.

The ratio of the peak intensity of the parallel and perpendicular component is known as the depolarization ratio (), defined in equation 1.

For example, a spectral band with a peak of intensity 10 units when the polarizers are parallel, and an intensity 1 unit when the polarizers are perpendicular, would have a depolarization ratio of 1/10 = 0.1, which corresponds to a highly polarized band.

The value of the depolarization ratio of a Raman band depends on the symmetry of the molecule and the normal vibrational mode, in other words, the point group of the molecule and its irreducible representation to which the normal mode belongs. Under Placzek's polarizability approximation, it is known that the depolarization ratio of a totally symmetric vibrational mode is less than 0.75, and that of the other modes equals 0.75. A Raman band whose depolarization ratio is less than 0.75 is called a , and a band with a depolarization ratio equal to or greater than 0.75 is called a .

For a spherical top molecule in which all three axes are equivalent, symmetric vibrations have Raman spectral bands which are completely polarized (). An example is the symmetric stretching or "breathing" mode of methane () in which all four  bonds vibrate in phase. However, for the asymmetric mode in which one  bond stretches while the other three contract, the Raman scattered radiation is depolarized.

For molecules of lower symmetry (symmetric tops or asymmetric tops), a vibration with the full symmetry of the molecule leads to a polarized or partially polarized Raman band (), while a less symmetric vibration yields a depolarized band ().

References

Raman spectroscopy
Ratios
Linda Cook (businesswoman). Linda Zarda Cook (born June 4, 1958) is an American businesswoman, who is CEO of Harbour Energy since 2014. She was previously CEO of Shell Gas & Power, part of Royal Dutch Shell, in the Netherlands until 2009. Cook was named the 44th most powerful woman in the world by Forbes magazine in September 2007.

Biography
Cook was raised in Shawnee, Kansas. She graduated from the University of Kansas in petroleum engineering in 1980.

She began her Shell career in 1980 as a reservoir engineer in the United States, advancing through the company to accept greater responsibilities in exploration and production with Shell U.S.A. Her first European assignment came in 1998, when she and her family moved to the Netherlands, where she led Shell International EP. She was CEO of the Gas & Power division from 2000 to 2003, then led Shell Canada for a year before returning to her previous post.

On May 26, 2009, Shell announced that Cook mutually agreed to step down after losing the race to become the company's next chief executive. Shortly following the announcement of her resignation was the news that her division, Gas and Power, would be absorbed into the new management structure being promoted by new chief executive Peter Voser. Shares in Shell fell 1.1 per cent or 18p to 1613p in morning trading. Cook had worked for Shell for 29 years. She lost out on a loyalty bonus of more than £800,000, but her severance pay came to about £5million, a figure determined by standard company and legal guidelines.

Cook joined the board of directors of The Boeing Company in 2003. She held four board assignments over the course of her tenure, including chair of the finance committee. On February 10, 2015, it was announced that Cook would not seek reelection to the board, ending her term that April. Cook has also been on the boards of directors of KBR and Marathon Oil.

Cook has been CEO of Harbour Energy since it was established in July 2014. In March 2021, the company merged and absorbed Chrysaor Holdings and Premier Oil to become the largest oil and gas producer in the North Sea.

References

American women chief executives
University of Kansas alumni
Living people
1958 births
American corporate directors
Boeing people
People from Shawnee, Kansas
Petroleum engineers
21st-century American women engineers
21st-century American engineers
Directors of Shell plc
21st-century American businesswomen
21st-century American businesspeople
Photoisomerization. In chemistry, photoisomerization is a form of isomerization induced by photoexcitation. Both reversible and irreversible photoisomerizations are known for photoswitchable compounds. The term "photoisomerization" usually, however, refers to a reversible process.

Applications
Photoisomerization of the compound retinal in the eye allows for vision.

Photoisomerizable substrates have been put to practical use, for instance, in pigments for rewritable CDs, DVDs, and 3D optical data storage solutions. In addition, interest in photoisomerizable molecules has been aimed at molecular devices, such as molecular switches, molecular motors, and molecular electronics.

Another class of device that uses the photoisomerization process is as an additive in liquid crystals to change their linear and nonlinear properties. Due to the photoisomerization is possible to induce a molecular reorientation in the liquid crystal bulk, which is used in holography, as spatial filter or optical switching.

Examples
Azobenzenes, stilbenes, spiropyrans, are prominent classes of compounds subject to photoisomerism.

In the presence of a catalyst, norbornadiene converts to quadricyclane via ~300nm UV radiation. When converted back to norbornadiene, quadryicyclane’s ring strain energy is liberated in the form of heat (ΔH = −89 kJ/mol). This reaction has been proposed to store solar energy (photoswitchs).

Photoisomerization behavior can be roughly categorized into several classes. Two major classes are trans–cis (or E–Z) conversion, and open-closed ring transition. Examples of the former include stilbene and azobenzene. This type of compounds has a double bond, and rotation or inversion around the double bond affords isomerization between the two states. Examples of the latter include fulgide and diarylethene. This type of compounds undergoes bond cleavage and bond creation upon irradiation with particular wavelengths of light. Still another class is the di-π-methane rearrangement.

Coordination chemistry
Many complexes are often photosensitive and many of these complexes undergo photoisomerization.  One case is the conversion of the colorless cis-bis(triphenylphosphine)platinum chloride to the yellow trans isomer.

Some coordination complexes undergo change in their spin state upon illumination, i.e. these are photosensitive spin crossover complexes.

See also
Photochromism

References

Chemical reactions
OOPSLA. OOPSLA (Object-Oriented Programming, Systems, Languages & Applications) is an annual ACM research conference. OOPSLA mainly takes place in the United States, while the sister conference of OOPSLA, ECOOP, is typically held in Europe.  It is operated by the Special Interest Group for Programming Languages (SIGPLAN) group of the Association for Computing Machinery (ACM).

OOPSLA has been instrumental in helping object-oriented programming develop into a mainstream programming paradigm. It has also helped incubate a number of related topics, including design patterns, refactoring, aspect-oriented programming, model-driven engineering, agile software development, and domain specific languages.

The first OOPSLA conference was held in Portland, Oregon in 1986. As of 2010, OOPSLA became a part of the SPLASH conference. SPLASH stands for Systems, Programming, Languages, and Applications: Software for Humanity.

Locations and organizers

References

External links
 
 OOPSLA history
 Official website—SPLASH 

Computer science conferences
Object-oriented programming
Association for Computing Machinery conferences
Programming languages conferences
Small extension node. The small extension node (SEN) is part of a US military communication system known as Mobile Subscriber Equipment (MSE). A SEN is composed of two shelters, a switching shelter and a Line of sight radio terminal shelter(LOS).

History
Prior to the advent of the satellite based Joint Network Node (JNN), the United States Army used a system known as Mobile Subscriber Equipment (MSE) in order to provide tactical battlefield communications.  MSE is a Line-Of-Sight (LOS) terrestrial based communications system limited by terrain and distance.  MSE is still in use in limited quantities. Developed as a direct replacement of the Multichannel communications telephone switching system used from the 1960 to early 2000s.

The MSE SEN primary role is to provide tactical telephone and data network communications to the battlefield. Capabilities include integration into existing and backwards compatible interfaces for older branch exchange, as well a field radio integration. This integration allows for the SEN capabilities to provide communications in battlefield as well as civilian communication disaster support.

Description
A SEN switching shelter contains switching, multiplexing, and communications security (COMSEC) equipment for secure digital voice and data communications. A single switching shelter is mounted on the back of a HMMWV, powered is provided by a 10 kW diesel generator, and the SEN is operated by up to a six soldier team. To provide communications for a Corps area the Signal Battalion would deploy forty SEN's, amongst Node Centers, Large Extension Nodes, and Radio Access Units.

The current switch is designated AN/TTC-48, with a suffix to identify each of the ten versions in operation - (V)1, V(2), A(V)1, A(V)2, B(V)1, B(V)2, C(V)1, C(V)2, C(V)3, and C(V)4. The (V)1 provides 26 digital lines and 10-digital trunks and the (V)2 provides 41 digital lines and 13-digital trunks. Both versions interface at various levels with the MSE Area Communication Systems through cable, via line of sight or via tactical satellite terminal.

References

Military communications
Scoop stretcher. The scoop stretcher (or clamshell, Roberson orthopedic stretcher, or just scoop) is a device used specifically for moving injured people. It is ideal for carrying casualties with possible spinal injuries.

A scoop stretcher has a structure that can be split vertically into two parts, with shaped 'blades' towards the centre which can be brought together underneath a patient.  The two halves are placed separately either side of the patient, and then brought together until securing clips at the top and bottom both engage.

Scoop stretchers reduce the chance of undesirable movement of injured areas during transfer of a trauma patient, as they maintain the patient in a supine alignment during transfer to a stretcher, vacuum mattress or long spine board). They are more comfortable than a long spine board for transport.

The scoop stretcher can be used for patient transport, provided the patient is strapped. However, the ninth edition of the ATLS Student Course Manual advises against using scoop stretchers for patient transport. For comfort and safety reasons, it is recommended to transfer the patient to a vacuum mattress instead, in which case the scoop stretcher is put on the transport device and then opened.

References
 

Medical transport devices
Lifting equipment
Thomson EF936x. The Thomson EF936x series is a type of Graphic Display Processor (GDP) by Thomson-EFCIS. The chip could draw at 1 million pixels per second, which was relatively advanced for the time of its release (1982 or earlier). There are various versions of the chip with slightly different capabilities.

The first version, EF9364 CRT Processor, was introduced in 1981.

In 1982 Commodore released a "High Resolution Graphics" board for the PET based on the EF9365 and EF9366 chips, allowing it to display  or  resolution graphics. The EF9366 was also used on the SMP-E353 graphic card for the Siemens  computer series and on the NDR-Klein-Computer introduced in 1984.

Version EF9369, introduced in 1984, was used on computers such as the Thomson MO5NR, MO6, TO8, TO9 and TO9+, and from 1985 to 1989 on the DAI Personal Computer.

Versions
Based on the 1989 data book published by the company, the EF936x series was split into Graphics Controllers and Color Palette models:

Graphics Controllers 
EF9364 CRT Processor introduced in 1981
EF9365  (interlaced), , , ; 50 Hz
EF9366  (non-interlaced); 50/60 Hz
EF9367  (interlaced),  (interlaced); 50/60 Hz (capable of SECAM system output for the French market).
SFF96364

Color Palette 
EF9369 - 4-bit DACs (16 out of 4096 colors - 12-bit RGB), generating gamma corrected (gamma 2.8) voltages.
TS9370 - 4-bit DACs (16 out of 4096 colors)

Capabilities
Integrated DRAM controller
Line drawing, with delta-x and delta-y limited to 255 each. Support for solid, dotted, dashed and dotted/dashed lines.
Built-in  pixel ASCII font. Support for rendering tilted characters, and scaling by integer factors (no antialiasing)
Clear screen
Light Pen support

The GPUs did not support direct access to the graphics memory, although a special command was provided to aid in implementing access to individual memory words.

Character Set 
The Thomson EF9365/6 used the following character, displayed with a  pixel font:

See also 
Thomson EF934x
Thomson MO5NR
Thomson MO6
Thomson TO8
Thomson TO9
Thomson TO9+
NDR-Klein-Computer
Commodore PET
DAI Personal Computer
List of home computers by video hardware

References

External links
 Full schematics
 PCB

Graphics chips
Thomson computers
Boule (crystal). A boule is a single-crystal ingot produced by synthetic means.

A boule of silicon is the starting material for most of the integrated circuits used today. In the semiconductor industry synthetic boules can be made by a number of methods, such as the Bridgman technique and the Czochralski process, which result in a cylindrical rod of material.

In the Czochralski process a seed crystal is required to create a larger crystal, or ingot. This seed crystal is dipped into the pure molten silicon and slowly extracted. The molten silicon grows on the seed crystal in a crystalline fashion. As the seed is extracted the silicon solidifies and eventually a large, cylindrical boule is produced.

A semiconductor crystal boule is normally cut into circular wafers using an inside hole diamond saw or diamond wire saw, and each wafer is lapped and polished to provide substrates suitable for the fabrication of semiconductor devices on its surface.

The process is also used to create sapphires, which are used for substrates in the production of blue and white LEDs, optical windows in special applications and as the protective covers for watches.

References

Crystals
Semiconductor growth
Bridgman–Stockbarger method. The Bridgman–Stockbarger method, or Bridgman–Stockbarger technique, is named after physicist Percy Williams Bridgman (1882–1961) and physicist Donald C. Stockbarger (1895–1952). The method includes two similar but distinct techniques primarily used for growing boules (single-crystal ingots), but which can be used for solidifying polycrystalline ingots as well.

Overview
The methods involve heating polycrystalline material above its melting point and slowly cooling it from one end of its container, where a seed crystal is located. A single crystal of the same crystallographic orientation as the seed material is grown on the seed and is progressively formed along the length of the container. The process can be carried out in a horizontal or vertical orientation, and usually involves a rotating crucible/ampoule to stir the melt.

The Bridgman method is a popular way of producing certain semiconductor crystals such as gallium arsenide, for which the Czochralski method is more difficult. The process can reliably produce single-crystal ingots, but does not necessarily result in uniform properties through the crystal.

The difference between the Bridgman technique and Stockbarger technique is subtle: While both methods utilize a temperature gradient and a moving crucible, the Bridgman technique utilizes the relatively uncontrolled gradient produced at the exit of the furnace; the Stockbarger technique introduces a baffle, or shelf, separating two coupled furnaces with temperatures above and below the freezing point. Stockbarger's modification of the Bridgman technique allows for better control over the temperature gradient at the melt/crystal interface.

When seed crystals are not employed as described above, polycrystalline ingots can be produced from a feedstock consisting of rods, chunks, or any irregularly shaped pieces once they are melted and allowed to re-solidify. The resultant microstructure of the ingots so obtained are characteristic of directionally solidified metals and alloys with their aligned grains.

Bagdasarov method 
A variant of the technique known as the horizontal directional solidification method (HDSM) developed by Khachik Bagdasarov () starting in the 1960s in the Soviet Union. It uses a flat-bottomed crucible made out of molybdenum with short sidewalls rather than an enclosed ampoule, and has been used to grow various large oxide crystals including Yb:YAG (a laser host crystal), and sapphire crystals 45 cm wide and over 1 meter long. However, the quality of the crystals grown by HDSM differ from the Czochralski method, due to the problem of the problematic presence of bubbles.

See also

 Float-zone silicon

References

Industrial processes
Semiconductor growth
Crystals
Methods of crystal growth
Seed crystal. A seed crystal is a small piece of single crystal or polycrystal material from which a large crystal of typically the same material is grown in a laboratory. Used to replicate material, the use of seed crystal to promote growth avoids the otherwise slow randomness of natural crystal growth, and allows manufacture on a scale suitable for industry.

Crystal enlargement
The large crystal can be grown by dipping the seed into a supersaturated solution, into molten material that is then cooled, or by growth on the seed face by passing vapor of the material to be grown over it.

Theory
The theory behind this effect is thought to derive from the physical intermolecular interaction that occurs between compounds in a supersaturated solution (or possibly vapor). In solution, liberated (soluble) molecules (solute) are free to move about in random flow. This random flow permits for the possibility of two or more molecular compounds to interact. This interaction can potentiate intermolecular forces between the separate molecules and form a basis for a crystal lattice. The placement of a seed crystal into solution allows the recrystallization process to expedite by eliminating the need for random molecular collision or interaction. By introducing an already pre-formed basis of the target crystal to act upon, the intermolecular interactions are formed much more easily or readily, than relying on random flow. Often, this phase transition from solute in a solution to a crystal lattice will be referred to as nucleation. Seeding is therefore said to decrease the necessary amount of time needed for nucleation to occur in a recrystallization process.

Uses
One example where a seed crystal is used to grow large boules or ingots of a single crystal is the semiconductor industry where methods such as the Czochralski process or Bridgman technique are employed.

Also during the process of tempering chocolate, seed crystals can be used to promote the growth of favorable type V crystals

See also
 Crystal structure
 Crystallization
 Laser heated pedestal growth
 Micro-pulling-down
 Polycrystal
 Single crystal
 Wafer (electronics)
 Disappearing polymorphs

References

Crystals