omniomni/omni-engineering huggingface dataset:
Stone–Wales defect. A Stone–Wales defect is a crystallographic defect that involves the change of connectivity of two π-bonded carbon atoms, leading to their rotation by 90° with respect to the midpoint of their bond. The reaction commonly involves conversion between a naphthalene-like structure into a fulvalene-like structure, that is, two rings that share an edge vs two separate rings that have vertices bonded to each other.

The reaction occurs on carbon nanotubes, graphene, and similar carbon frameworks, where the four adjacent six-membered rings of a pyrene-like region are changed into two five-membered rings and two seven-membered rings when the bond uniting two of the adjacent rings rotates. In these materials, the rearrangement is thought to have important implications for the thermal, chemical, electrical, and mechanical properties. The rearrangement is an example of a pyracyclene rearrangement.

History 
The defect is named after Anthony Stone and David J. Wales at the University of Cambridge, who described it in a 1986 paper on the isomerization of fullerenes. However, a similar defect was described much earlier by G. J. Dienes in 1952 in a paper on diffusion mechanisms in graphite   and later in 1969 in a paper on defects in graphite by Peter Thrower. For this reason, the term Stone–Thrower–Wales defect is sometimes used.

Structural effects 
The defects have been imaged using scanning tunneling microscopy and transmission electron microscopy and can be determined using various vibrational spectroscopy techniques.

It has been proposed that the coalescence process of fullerenes or carbon nanotubes may occur through a sequence of such a rearrangements. The defect is thought to be responsible for nanoscale plasticity and the brittle–ductile transitions in carbon nanotubes.

Chemical details 
The activation energy for the simple atomic motion that gives the bond-rotation apparent in a Stone–Wales defects is fairly high—a barrier of several electronvolts. but various processes can create the defects at substantially lower energies than might be expected.

The rearrangement creates a structure with less resonance stabilization among the sp2 atoms involved and higher strain energy in the local structure. As a result, the defect creates a region with greater chemical reactivity, including acting as a nucleophile and creating a preferred site for binding to hydrogen atoms. The high affinity of these defects for hydrogen, coupled with the large surface area of the bulk material, might make these defects an important aspect in the use of carbon nanomaterials for hydrogen storage. Incorporation of defects along a carbon-nanotube network can program a carbon-nanotube circuit to enhance the conductance along a specific path. In this scenario, the defects lead to a charge delocalization, which redirects an incoming electron down a given trajectory.

References

External links

Carbon nanotubes
Crystallographic defects
Long-running transaction. Long-running transactions (also known as the saga interaction pattern) are computer database transactions that avoid locks on non-local resources, use compensation to handle failures, potentially aggregate smaller ACID transactions (also referred to as atomic transactions), and typically use a coordinator to complete or abort the transaction. In contrast to rollback in ACID transactions, compensation restores the original state, or an equivalent, and is business-specific. For example, the compensating action for making a hotel reservation is canceling that reservation.

A number of protocols have been specified for long-running transactions using Web services within business processes. OASIS Business Transaction Processing and WS-CAF are examples. These protocols use a coordinator to mediate the successful completion or use of compensation in a long-running transaction.

See also
Optimistic concurrency control
Long-lived transaction

References

Data management
Transaction processing
Joseph I. Goldstein. Joseph Irwin Goldstein (January 6, 1939 – June 27, 2015) was an American scientist and engineer, working mainly in the fields of materials science and mechanical engineering. He was a Professor of Mechanical Engineering and emeritus Dean of Engineering at the University of Massachusetts Amherst. His research into the nature of outer-space materials led to the naming of an asteroid after him in 2000, 4989 Joegoldstein. 

His early research was at MIT, where he received a B.S. in 1960, an S.M. in 1962 and an Sc.D. in 1964.

From 1964 to 1983, Goldstein was a professor of Materials Science and Engineering at Lehigh University. During a sabbatical year in 1975, Goldstein discovered that analytical electron microscopy could resolve the solute profiles in synthetic meteoritic materials. He used the technique of AEM to supplement his extensive Scanning Electron Microscopy techniques. He initiated the Lehigh University Summer Microscopy School in 1970 and these continue today, teaching both SEM and AEM microprobe techniques.  Goldstein was the lead author, in collaboration with several fellow LUSMS faculty members, of four editions of Scanning Electron Microscopy and X-Ray Microanalysis.  The text is used worldwide in  electron microscopy seminars and graduate courses.

In 1983, Goldstein became Vice President for Graduate Studies and Research at Lehigh.

In 1990, Goldstein moved to UMass to become Dean of Engineering, a position he held until 2004.

In 1999 he received the Henry Clifton Sorby Award of the  International Metallographic Society.

The asteroid 4989 Joegoldstein was named after Goldstein in 2000 by Schelte J. Bus, who had discovered the asteroid in 1981 at the Anglo-Australian Telescope. It was named in honor of Goldstein because of his outstanding contributions to the science of meteoritics.

In 2005 he received the highest award of the Meteoritical Society, the Leonard Medal, for work on metal, phosphide, carbide, and sulphide in meteorites and lunar rocks; the formation of the Widmanstätten pattern and the determination of cooling rates in irons, stony-irons, and chondrites; the nature of
plessite and martensite formation; and determinations of phase diagrams for the Fe-Ni, Fe-Ni-P, Fe-Ni-Co, Fe-Ni-C, and Fe-Ni-S systems

References

External links
Joe Goldstein's faculty homepage

American engineers
Lehigh University faculty
University of Massachusetts Amherst faculty
1939 births
2015 deaths
Massachusetts Institute of Technology alumni
Silicon tetrafluoride. Silicon tetrafluoride or tetrafluorosilane is a chemical compound with the formula SiF4.  This colorless gas is notable for having a narrow liquid range: its boiling point is only 4 °C above its melting point. It was first prepared in 1771 by Carl Wilhelm Scheele by dissolving silica in hydrofluoric acid, and later synthesized by John Davy in 1812.  It is a tetrahedral molecule and is corrosive.

Occurrence
Volcanic plumes contain significant amounts of silicon tetrafluoride. Production can reach several tonnes per day. Some amounts are also emitted from spontaneous coal fires. The silicon tetrafluoride is partly hydrolysed and forms hexafluorosilicic acid.

Preparation
 is a by-product of the production of phosphate fertilizers wet process production, resulting from the attack of HF (derived from fluorapatite protonolysis) on silicates, which are present as impurities in the phosphate rocks. The hydrofluoric acid and silicon dioxide (SiO2) react to produce hexafluorosilicic acid:
 6 HF + SiO2  →   H2SiF6 + 2 H2O

In the laboratory, the compound is prepared by heating barium hexafluorosilicate (Ba[SiF6]) above  whereupon the solid releases volatile , leaving a residue of .

 

Alternatively, sodium hexafluorosilicate () may also be thermally decomposed at — (optionally in inert nitrogen gas atmosphere)

Uses
This volatile compound finds limited use in microelectronics and organic synthesis.

It's also used in production of fluorosilicic acid (see above).

Staying in the 1980s, as part of the Low-Cost Solar Array Project by Jet Propulsion Laboratory, it was investigated as a potentially cheap feedstock for polycrystalline silicon production in fluidized bed reactors. Few methods using it for the said production process were patented.

The Ethyl Corporation process 
In 80s the Ethyl Corporation came up with a process that uses hexafluorosilicic acid and sodium aluminium hydride (NaAlH4) (or other alkali metal hydride) to produce silane (SiH4).

Safety 
In 2001 it was listed by New Jersey authorities as a hazardous substance that is corrosive and may severely irritate or even burn skin and eyes. It is fatal if inhaled.

See also 

 SiH4 (silane)
 Hexafluorosilicic acid

References

 

Fluorides
Nonmetal halides
Inorganic silicon compounds
Silanes
List of aircraft of the United Kingdom in World War II. Here is a list of aircraft used by the British Royal Air Force (RAF), Royal Navy Fleet Air Arm (FAA), Army Air Corps (AAC) and British Overseas Airways Corporation (BOAC) during the Second World War.

Fighters and fighter-bombers

Torpedo bombers, dive bombers and army cooperation

Level bombers

Maritime patrol and coastal reconnaissance

Photo reconnaissance

Trainers and target tugs

Transport and communications

Experimental and other

Prototypes & trials

Gliders

See also
List of aircraft of the Royal Air Force
List of aircraft of the Fleet Air Arm
List of Fleet Air Arm aircraft in World War II
List of aircraft of World War II

References

Notes

Citations

Bibliography
O. Thetford: Aircraft of the Royal Air Force since 1918 6th edition. Putnam & Co., London,UK, 1976, .

World War II aircraft
Aircraft
World War II aircraft
United Kingdom

de:Britische Flugzeuge im Zweiten Weltkrieg
Zone Zeal. Zone Zeal was the 2002 game for the FIRST Robotics Competition.  In it, robots playing in alliances of two competed to move goals and balls into various zones within the playing field.

Playing Field

The playing field was divided into fifths called zones. At the beginning of the match, there were 40 balls arranged along the sides of the field in the center zone and the two adjacent zones. In the center zone were three mobile goals.

The zones were numbered 1 to 5. The Blue team could score by placing ball-filled goals in zones 4 or 5, and could score a bonus 10 points for every goal in zone 4.  At the end of the match, for every robot Blue had in zone 1, Blue would score 10 points. For the red alliance, it was the opposite. Balls could be scored in zones 1 or 2, goals would receive bonus points for being in zone 2, and robots scored 10 points each for ending the match in zone 5.

Scoring
The primary source of points in Zone Zeal was placing balls in the mobile goals, then moving the goal into the appropriate zone. For every ball in a goal, an alliance received 1 point. For every goal in the alliance's goal zone at the end of the match, the alliance would receive 10 points. Further, the team received 10 points for every robot in the robot zone at the end of the match.

Events
The following regional events were held in 2002:
 Buckeye Regional - Cleveland, Ohio
 Canadian Regional - Mississauga, Ontario
 Great Lakes Regional - Ypsilanti, Michigan
 Johnson & Johnson Mid-Atlantic Regional - New Brunswick, New Jersey
 Lone Star Regional - Houston, Texas
 Motorola Midwest Regional - Evanston, Illinois
 NASA Kennedy Space Center Southeast Regional - Kennedy Space Center, Florida
 NASA Langley/VCU/School of Engineering - Richmond, Virginia
 New York City Regional - New York City
 Pacific Northwest Regional - Seattle, Washington
 Philadelphia Regional - Philadelphia, Pennsylvania 
 SBPLI Long Island Regional - Long Island, New York
 Silicon Valley Regional - San Jose, California
 Southern California Regional - Los Angeles, California
 Western Michigan Regional - Grand Rapids, Michigan
 UTC New England Regional - New Haven, Connecticut

The championship was held at Epcot Center, Disney World, Orlando.

References

Further reading

2002 in robotics
FIRST Robotics Competition games
Cauchy–Born rule. The Cauchy–Born rule or Cauchy–Born approximation is a basic hypothesis used in the mathematical formulation of solid mechanics which relates the movement of atoms in a crystal to the overall deformation of the bulk solid. A widespread simplified version states that in a crystalline solid subject to a small strain, the positions of the atoms within the crystal lattice follow the overall strain of the medium. To give a more precise definition, consider a crystalline body where the position of the atoms can be described by a set of reference lattice vectors . The Cauchy-Born rules states that if the body is deformed by a deformation whoes gradient is , the lattice of the deform body can be described by . The rule only describes the lattice, not the atoms.

The currently accepted form is Max Born's refinement of Cauchy's original hypothesis which was used to derive the equations satisfied by the Cauchy stress tensor. The approximation generally holds for face-centered and body-centered cubic crystal systems. For complex lattices such as diamond, however, the rule has to be modified to allow for internal degrees of freedom between the sublattices. The approximation can then be used to obtain bulk properties of crystalline materials such as stress-strain relationship.

For crystalline bodies of finite size, the effect of surface stress is also significant. However, the standard Cauchy–Born rule cannot deduce the surface properties. To overcome this limitation, Park et al. (2006) proposed a surface Cauchy–Born rule. Several modified forms of the Cauchy–Born rule have also been proposed to cater to crystalline bodies having special shapes. Arroyo & Belytschko (2002) proposed an exponential Cauchy Born rule for modeling of mono-layered crystalline sheets as two-dimensional continuum shells. Kumar et al. (2015) proposed a helical Cauchy–Born rule for modeling slender bodies (such as nano and continuum rods) as special Cosserat continuum rods.

References
 .
 .
 .
 .

Crystallography
Max Born
George Westinghouse Bridge. George Westinghouse Memorial Bridge in East Pittsburgh, Pennsylvania, carries U.S. Route 30, the Lincoln Highway, over the Turtle Creek Valley near to where it joins the Monongahela River Valley east of Pittsburgh. The reinforced concrete open-spandrel deck arch bridge has a total length of  comprising five spans. The longest, central span is , with the deck height  above the valley floor, for a time the world's longest concrete arch span structure. It cost $1.75 million ($ in  dollars). The design engineers were Vernon R. Covell and George S. Richardson, with architectural design by Stanley Roush. The pylons at the ends of the bridges feature Art Deco reliefs by Frank Vittor.

The bridge is named for George Westinghouse (October 6, 1846 – March 12, 1914), the American entrepreneur and engineer. Nearby was the famous Westinghouse Electric Corporation East Pittsburgh Works, which is now an industrial park. Notable attractions visible while driving across the bridge include the Edgar Thomson Steel Works (U.S. Steel Mon Valley Works) and Kennywood Park.

Popular culture
The bridge was featured in the 2011 film Warrior starring Joel Edgerton and Tom Hardy.

See also
 
 
 
 Westinghouse Memorial
 List of bridges documented by the Historic American Engineering Record in Pennsylvania
 List of bridges in the United States by height

References

Further reading

External links

George Westinghouse Memorial Bridge at pghbridges.com

Bridges completed in 1932
Road bridges on the National Register of Historic Places in Pennsylvania
Historic American Engineering Record in Pennsylvania
Lincoln Highway
Pittsburgh History & Landmarks Foundation Historic Landmarks
U.S. Route 30
Bridges of the United States Numbered Highway System
National Register of Historic Places in Allegheny County, Pennsylvania
Open-spandrel deck arch bridges in the United States
Concrete bridges in the United States
Bridges in Allegheny County, Pennsylvania
Andrews A1. The Andrews A1 was a flying ½-scale replica of the un-built Andrews A2 New Zealand agricultural aircraft.

Development
The Andrews A2 was designed by C.G. Andrews in Wellington, New Zealand, intended to compete in the market for a de Havilland Tiger Moth replacement in New Zealand's Aerial Topdressing industry.  From the outset it was intended that a ½-scale model of the type be built and flown to prove the design, and this became the Andrews A1.

The Andrews A1 is a conventional low-wing thick-section monoplane of plywood-covered spruce and steel construction with a bubble-type canopy, powered by a 65 hp Continental flat 4 air-cooled engine, and with spatted tailwheel undercarriage.

Operational history
First flown in 1957, the A1 successfully completed flight testing, but by that time the market for the larger Andrews A2 was clearly dominated by the more modern Fletcher Fu24.

The sole Andrews A1, ZK-BLU, was sold to a private owner.  It was owned for many years by Alan Rowe, best known as the designer of the Rowe R6b model aircraft, and is now owned by P.G. Alexander of Blenheim, continuing to fly regularly.

Variants
Andrews A2A proposed agricultural aircraft to be optimised for Aerial topdressing.
Andrews A1A flying scale replica of the A2 built to verify aerodynamic qualities and flying characteristics.

Specifications (A1)

Notes

References

1960s New Zealand agricultural aircraft
Aircraft manufactured in New Zealand
Low-wing aircraft
Single-engined tractor aircraft
Aircraft first flown in 1957
Bennett Airtruck. The  PL-11 Airtruck is a New Zealand agricultural aircraft.

A strikingly unusual aircraft, the PL-11 Airtruck was developed from the Kingsford Smith PL.7 as a replacement for the de Havilland Tiger Moth in the New Zealand aerial topdressing market by Luigi Pellarini for Waitomo Aircraft. The prototype was constructed using bits of war surplus ex-RNZAF North American Harvards. It featured all aluminium structure, a high-wing monoplane with a steel stub wing and V lift struts, steerable tricycle undercarriage, an extremely stubby pod fuselage, the cockpit (made from shortened Harvard glazing) being mounted directly over the radial engine, providing excellent forward view and very high drag, beneath it was room for a superphosphate hopper or up to 5 people in a cabin. The strangeness was completed by twin booms each supporting unconnected tail units, (the idea being a truck could reverse between the tail units to load the hopper). Despite the outlandish appearance, the Airtruck was surprisingly successful, if unable to compete with the Fletcher Fu24 in its design market.

The first Bennett Airtruck, ZK-BPV, took to the air on 2 August 1960, and crashed during trials in October 1963. Following company reorganization the second example, known as the Waitomo PL-11 Airtruck and registered ZK-CKE, flew in March 1965. It commenced commercial operations late in February 1967 but crashed a few days later. An unconfirmed report indicates that a third airframe was largely constructed but never flew.

A shortage of Harvard parts led to the type being redesigned for all-new construction by the Transavia Corporation, as the Transavia PL-12 Airtruk, 118 of which were produced in Australia between 1965 and 1985.

Specifications (Waitomo Airtruck)

References

 Taylor, John W. R. Jane's All The World's Aircraft 1965-66. London:Sampson Low, Marston & Company, 1965.

External links

Airliners.net info page
New Zealand forum discussion

1960s New Zealand agricultural aircraft
Aircraft manufactured in New Zealand
High-wing aircraft
Twin-boom aircraft
Single-engined tractor aircraft
Aircraft first flown in 1960
KFX. KFX may refer to:

Computing
 KFX (program), the kernel language of FX-87, a polymorphic typed functional language
 Kameleon FireEx KFX, a computational fluid dynamics simulation program focusing on gas dispersion and fire simulation.
 .kfx, a proprietary ebook format for the Amazon Kindle
 Kofax (stock ticker: KFX), process automation software provider

Other uses
 Kullui (ISO 639 language code: kfx)
 KAI KF-X, a South Korean project for development of an indigenous fighter aircraft
 KFX, a series of ATVs, see List of Kawasaki motorcycles
 OMX Copenhagen 20, a stock market index for the Copenhagen Stock Exchange, formerly known as KFX

See also

 KFXS radio station
 
 
 KF (disambiguation)
Gujranwala Electric Power Company. Gujranwala Electric Power Company (GEPCO; ) is an electric distribution company which supplies electricity to the Gujranwala region in Punjab, Pakistan. The jurisdiction of the company includes Sialkot, Narowal, Gujranwala, Gujrat, Hafizabad, Wazirabad and Mandi Bahauddin districts. The current Chief Executive Officer of GEPCO is Engineer Muhammad Ayub.

See also

 List of electric supply companies in Pakistan

References

Distribution companies of Pakistan
Gujranwala District
Government-owned companies of Pakistan
Energy in Punjab, Pakistan

at

gmail com 

ashmuelisrael
Multan Electric Power Company. Multan Electric Power Company (MEPCO) (), formerly known as Multan Power Supply Company, is an electric distribution company which supplies electricity to thirteen districts of South Punjab, Pakistan. This company generates electric power from water (hydro-electric power) and distributes it to approximately thirty-four million people of the area. MEPCO is a licensee who has been granted a license by the NEPRA for the distribution of electricity exclusively to service territory spread over thirteen administrative districts of Southern Punjab.

History 
Multan Electric Power Company was founded as Multan Power Supply Company in 1922 during British India-era. In 1972, the company was nationalized. Subsequently, it was taken over by the Government of Pakistan. It was publicly listed on Karachi Stock Exchange until 1985 when it was de-listed from the exchange.
 
On 14 May 1998, Government of Pakistan decided to go with the corporatization of the energy sector in Pakistan. MEPCO was established to acquire all properties, rights, assets, obligations, and liabilities of the defunct Multan Area Electricity Board, grid stations, and transmission lines of the supply system. After 24 years of service in 2022, MEPCO has been directly and exclusively supplying electricity to 34 million people in 13 districts of South Punjab.

Operations 
MEPCO is the largest power distribution company in Pakistan operating exclusively in 13 administrative districts of southern Punjab i.e. Multan, Muzaffargarh, Layyah, Dera Ghazi Khan, TTaunsa Sharif, Kot Addu, Tribal area of Dera Ghazi Khan, Fort Manro, Rajanpur, Lodhran, Jalalpur Pirwala, Bahawalpur, Rahim Yar Khan, Khanewal, Sahiwal, Pakpattan, Vehari and Bahawalnagar.MEPCO manages a complex transmission and distribution network of over 82,132 km of lines, 786 grid stations, and 672 feeders. In other words, it covers 50 constituencies of National Assembly of Pakistan and 104 constituencies of the Punjab Assembly.

The company's service territory is primarily rural, so its customer profile is heavily dominated by the domestic category and that too by lifeline customers.

See also

 List of electric supply companies in Pakistan
 Pakistan Water & Power Development Authority (WAPDA)
 National Electric Power Regulatory Authority (NEPRA)

References

1922 establishments in British India
Distribution companies of Pakistan
Companies based in Multan
Government-owned companies of Pakistan
Energy in Punjab, Pakistan
Companies formerly listed on the Karachi Stock Exchange