omniomni/omni-engineering huggingface dataset:
Pentafluorobenzoic acid. Pentafluorobenzoic acid  (PFBA) is an organofluorine compound with the formula C6F5CO2H.  It is a white crystalline powder that has a high solubility in water.  Its pKa of 1.48 indicates that it is a strong acid.

Preparation
Pentafluorobenzoic acid is prepared by treating pentafluorophenyllithium (or pentafluorophenyl Grignard reagent) with carbon dioxide.  These reagents are usually prepared in situ from pentafluorobenzene and bromopentafluorobenzene.

It arises via the reaction of perfluorotoluene with trifluoroacetic acid and antimony pentafluoride.

Substitution reactions
Substitution of fluoride occurs typically at the para position.  This reaction has been used to anchor the −C6F4CO2H group to surfaces.  Magnesium methoxide results in ortho methoxylation.  Cleavage of this ether gives tetrafluorosalicylic acid.  Via similar ortho-directed reactivity, nickel complexes catalyse the defluoridation of 2 and 5 positions.  Without nickel, defluoridation occurs with para-selectivity.

References 

Benzoic acids
Perfluorinated compounds
Pentafluorophenyl compounds
Virtual manufacturing network. A Virtual Manufacturing Network is a manufacturing network which is not owned by a simple company, but it is built with the use of ICT for bringing together different suppliers and alliance partners creating in such a way a virtual network which is able to operate as a solely owned supply network. 
A Virtual Manufacturing Network is in this way a Collaborative network of manufacturing enterprises (from OEMs to Suppliers), which are connected by means of ICT for configuring, managing and monitoring the manufacturing process.

Many companies have adopted a philosophy of acquiring worldwide resources through a virtual network for minimizing expenses in their whole operation, focusing on core competences and relying to other companies with specific expertise to take over the parts of the manufacturing process they cannot perform by themselves.
The evolution of a Virtual Manufacturing Network is a Dynamic Manufacturing Network, which describes a more flexible and agile manufacturing network, that is able to be instantiated or dissolved quite rapidly, in order to meet emerging market needs and business opportunities.

Notes 

Manufacturing
Networks
Sigvald Johannesson. Sigvald Johannesson  (1877–1953) was a civil engineer best known for his design of the Pulaski Skyway.

Johannesson was a graduate of the University of Copenhagen who later worked on the London Underground. He emigrated to the United States and worked on the North River Tunnels and the Hudson and Manhattan Railroad tunnels under the Hudson River. He joined the New Jersey Highway Department (now the New Jersey Department of Transportation) during the early development of the Skyway project and is considered to be responsible for its ultimate design. Johannesson worked the agency until his retirement in 1948 as head of the Division of Planning and Economics. In 1931, he published a seminal work entitled Highway Economics. He died in 1953.

References 

1877 births
1953 deaths
Danish civil engineers
American civil engineers
Engineers from New Jersey
University of Copenhagen alumni
Fred Hart (engineer). Frederick Leslie Hart (born 12 September 1914, died 16 July 2008)  is best known as an automotive engineer for Ford in England. Initially working for the City of London, he joined Ford during World War II as a draughtsman and continued with Ford after the war to become chief engineer in 1963. In 1969 Hart moved to GKN Sankey to become technical director. He retired in 1979.

Early years
Hart was educated in Walthamstow grammar school and undertook engineering classes at night school. Initially working for the city of London, he then became a landscape architect. In 1940 he joined Ford as part of the war effort to become a draughtsman and took part in the design of armoured vehicles. Hart married Margaret Lydia Bennett in 1943, and they had a son named John.

Career
After the war, Hart continued with Ford where he became executive engineer of light cars in 1957, his first major project being the Ford Anglia in 1959. He played a major role in the development of the new Ford Cortina launched in 1962 and is credited with specifically developing the successful "aeroflow" ventilation system. He was promoted to chief engineer in 1963 and was involved with the Ford Corsair and the 1966 Zephyr and Zodiac.

In 1969 Hart left Ford to join GKN Sankey in Telford as their technical director and to develop a car specifically for drivers who used wheelchairs, originally known as the Minissima and later as the Elswick Envoy. The project won a Design Council commendation in 1978 but was too expensive for government support and was cancelled. GKN sold the rights to Elswick, and a small number were built and sold as the Envoy.

References

1914 births
2008 deaths
Ford people
British automotive engineers
Province-class fast attack craft. The Province-class fast attack craft, also known as the Dhofar class, is a British-built series of missile-armed fast attack craft for the Royal Navy of Oman.

Design
The Province class was designed and built by the British shipyard Vosper Thornycroft based on their  which they had built for the Egyptian Navy. The first ship of the class, Dhofar was ordered in 1980, with further ships (with slightly modified armament and equipment) ordered in 1981 and 1986.

The ships are  long overall and  between perpendiculars, with a beam of  and a draught of . Displacement is  light and  full load. They are powered by four Paxman Valenta 18RP200 diesel engines, each driving a propeller shaft, with a total power of , giving a speed of . Two  electric motors are fitted for manoeuvring purposes. 45.5 tons of fuel are carried, giving a range of  at .

The ships' main anti-ship armament is the Exocet anti-ship missile. Dhofar can carry six MM-40 Exocets missiles, while the other three ships of the class can carry eight MM-40s, in two quadruple mounts. An OTO Melara 76 mm gun is mounted forwards, while a twin Breda Bofors 40 mm gun is mounted aft. In addition, two 12.7 mm (.50 inch) machine guns are fitted.

Ships in class

Citations

References

Missile boat classes
Dong Neng-2. Dong Neng-2 () is an anti-satellite missile of the People's Liberation Army, developed in the early 2010s. It is designed as a low-Earth orbit interceptor which destroys orbiting satellites by high speed kinetic impact.

See also
2007 Chinese anti-satellite missile test

References

Anti-satellite missiles
Anti-ballistic missiles of the People's Republic of China
Military equipment introduced in the 2010s
Thomas Research Products. Thomas Research Products is a lighting manufacturer that is wholly owned by Hubbell Lighting Inc.  Based in Elgin, Illinois, the company designs, manufacturers and supplies energy-saving electronic lighting components and integrated light engine modules for luminaires.

Company Profile 

Thomas Research Products was founded in 1997 as a manufacturer of quartz restrike controls which sense when a high intensity discharge light is extinguished, and automatically light a standby secondary light source in commercial and industrial lighting.

Over time, the company expanded its product line to include additional electronic controls for both HID and fluorescent lighting. The company also added LED power supplies, known as drivers, and accessories.

In 2012, the company began to develop LED light engines, beginning with the introduction of a complete module that provided an energy efficiency rating exceeding 100 lumens per watt. The following year, the company entered the AC LED market with light engine modules that do not require LED drivers. In 2014, the company moved to a larger facility in Elgin, IL with larger manufacturing, warehouse, engineering and office space.

Company history

 1997 - Thomas Research Products founded as a manufacturer of quartz restrike controls for HID lamps. 
 1998 - Expands product line to include additional HID and fluorescent controls.
 2000 - Thomas Research Products becomes part of the newly formed Varon Lighting Group.  
 2007 - Adds LED, fluorescent, HID and induction surge protectors to product line. 
 2008 - The company's contact voltage detection switch wins 2008 LFI Innovation Award.
 2008 - Thomas Research Products adds LED drivers to its product line.
 2008 - The Varon Lighting Group acquired by Hubbell Lighting Inc., Thomas Research Products continues to operate independently. 
 2010 - Continued expansion of LED driver product line.
 2012 - Introduced step-dimming modules for LED luminaires. LED Core™ Light Engine Module Exceeds 100 lumens per watt efficiency.
 2013 - Developed more advanced surge protectors for outdoor luminaires.
 2014 - The company moved to Elgin, IL. Introduced complete line of standard DC-based light engines

References

External links 
 Thomas Research Products website.

American brands
Lighting brands
The Thomas Aveling School. The Thomas Aveling School is a secondary school and sixth form with academy status, located in Rochester, Kent, England.

History 
The school is named after Thomas Aveling, inventor of the traction engine and a partner in the world's largest manufacturer of steamrollers in the 19th century, Aveling and Porter, who were located in Rochester. The school badge depicts one of Aveling's steamrollers, below two trees that cross one another to represent the merging of two schools. 

The Thomas Aveling School was formed in 1990 after three local schools, (Warren Wood Boys, Warren Wood Girls and Highfield) were closed. The former Warren Wood Boys School site was re-developed with new facilities added to the refurbished classroom and administration block and school hall. During the 1990s, the school became grant-maintained, enabling the Board of Governors to expand the facilities, including the addition of a sports hall in 1997. In 2001, the school received a positive Ofsted report.

In 1997, with the lapse of the grant-maintained system within England, the school became a foundation school and was taken under the authority of the newly formed Medway LEA.  The school went on to gain Technology College status and Training School status. The school became an academy in September 2011.

Site
Since its creation in 1990, new facilities have been built at the school. These include development of the Learning Resource Centre and Community Library (2002), a music recording studio (2003), fitness and media suites (2004), a post-16 science lab (2005), a design & technology suite (2006), a drama facility (2008) and, more recently, sports facilities.

Subjects 

In Years 7 and 8 students study English, Maths, Science, Design Technology, PE, RE, PSHE, History, Geography, Art, Dance, Drama, Music and a Modern Foreign Language.

When entering Year 9 all students study English, Maths, Science, RE and PSHE. Students then have a free choice of four other subjects to study at GCSE. The options include Art & Design, Business studies, Dance, Drama, Geography, History, ICT, Media studies, Modern Foreign Languages and Music.

League Tables and Examination results 
A 2012 BBC report says that 45% of students received 5 A*-Cs in GCSE subjects. 85% of sixth form students attained three A-levels. As a result, the school became the 12th best secondary school in the Medway towns based on GCSE results, and 10th based on students getting three A-levels or equivalent.

Houses 
The house system at the school was created in 2010. There are four houses and colours associated with each: Victory (purple), Resolute (red), Cavalier (green), and Achilles (yellow). The Houses are named after ships built in the nearby historic Chatham Dockyard. The forms are split into Houses throughout all year groups, excluding Year 13.

Notable former pupils 
 Kelly Brook – Model and television presenter

References

External links 
 

Academies in Medway
Educational institutions established in 1990
1990 establishments in England
Secondary schools in Medway
Rochester, Kent
Program dependence graph. A Program Dependence Graph (PDG) is a directed graph of a program's control and data dependencies. Nodes represent program statements and edges represent dependencies between these statements.

PDGs are used in optimization, debugging, and understanding program behavior. One example of this is their utilization by compilers during dependence analysis, enabling the optimizing compiler to make transformations to allow for parallelism.

See also

 Dependency graph
 Control-flow graph
 Data-flow analysis
 Static program analysis

References

Parallel computing
Application-specific graphs
Diisopropyl methylphosphonate. Diisopropyl methylphosphonate (DIMP), also known as diisopropyl methane-phosphonate and phosphonic acid and methyl-bis-(1-methylethyl)ester, is a chemical by-product in the production of sarin gas when two equivalents of isopropyl alcohol react with methylphosphonyl difluoride instead of one.

DIMP is a colorless liquid that has been shown to affect the hematological (blood forming) system in animals. Its chemical formula is C7H17O3P.

It degrades into isopropyl methylphosphonic acid.

History
DIMP is a chemical by-product resulted from the manufacture of sarin (GB).

Use
No commercial uses of DIMP are known to exist.

Occurrences
DIMP is not known to occur naturally in the environment.

Productions

Synthesis
DIMP can be prepared by a gradual addition of triisopropyl phosphite with methyl iodide, utilizing distillation technique.

References

Phosphonates
Isopropyl esters
Nerve agent precursors
Eniak Antique. The Eniak Antique is an automobile built in Argentina by Eniak beginning in 1983. The Eniak company had hitherto mainly focused on electronics, some of which found their way into cars. The Antique was a metal-bodied, fiberglass-bumpers and doors, two-seat roadster that took its styling cues from the classic sports cars of the thirties, with some resemblance to the Alfa Romeo 8C. The cars have rear-wheel drive and a 1.8 liter inline-four with  or  depending on the state of tune. The engines came from the Volkswagen 1500 (originally a Hillman Avenger unit) and were tuned by Balestrini. The round gauges on the dashboard were of Eniak's own manufacture, and a traditional looking large four-spoke wooden steering wheel finished the job. A few cars were shipped to Japan in 1988, but Eniak still had to shut its doors in 1989.

External links
 Argentinian Eniak Antique registry  (in Spanish)

References

Cars of Argentina
Retro-style automobiles
Cars introduced in 1983
Cars discontinued in 1989
Tupolev Tu-121. The Tupolev Tu-121 was an unmanned aircraft, intended for use as a cruise missile, designed by Tupolev in the Soviet Union during the Cold War.

Development
In 1957, the Tupolev Design Bureau was in very good standing. Their Tu-95 was being actively introduced to the Air Force, their Tu-16 was being produced in three plants. Tupolev, however, was worried about Nikita Khrushchev's growing interest in rocket weapons. The USSR had made significant progress in rocket science and was preparing to launch their first rocket – the R-7. Rockets seemed invincible for existing and future anti-aircraft systems.  Soviet bombers were not so lucky, being extremely vulnerable. The NORAD system, which was being developed and deployed by the United States at the time was practically impermeable for the strategic bombers of that era.

Various attempts to arm Tu-95s with missiles had a serious drawback – the bomber itself remained vulnerable to interceptors and ground-to-air missiles.

Tu-121 was conceived as an aircraft able to reach speeds of over 2,000 km/h and a flight altitude of 50 km which would allow it to easily penetrate both American air- and missile defence systems.

However, even at the early stages, Tupolev himself realized that his bureau was unable to develop such an aircraft. The biggest problem was immense heat. The materials necessary to build the heat-shield were developed only in the 1980s for the Buran programme.

The aircraft was built and several test launches were performed. However, it did not go beyond the prototype phase. The R-12 rocket, developed by Mikhail Yangel had better range and accuracy. On 5 February 1960, the project was officially cancelled.

The aircraft was a full-metal monoplane made almost entirely of traditional materials. The wing had no high-lift devices. The aircraft was piloted using vertical and horizontal stabilizers. Most of the fuselage consisted of fuel tanks.

Specifications

See also

References

Tu-0121
1950s Soviet experimental aircraft
Cruise missiles of the Soviet Union
List of DNA nanotechnology research groups. This list of DNA nanotechnology research groups gives a partial overview of academic research organisations in the field of DNA nanotechnology, sorted geographically. Any sufficiently notable research group (which in general can be considered as any group having published in well regarded, high impact factor journals) should be listed here, along with a brief description of their research.

North America

Asia

Europe

References 

DNA nanotechnology
DNA
Research groups
Inherent vice. Inherent vice is the tendency in physical objects to deteriorate because of the fundamental instability of the components of which they are made, as opposed to deterioration caused by external forces.   All objects have some kind of inherent vice as a result of the baseline law of entropy.

Preservation issues

The term is broadly used in archival practice to recognize the material constraints of preservation activities. For example, many kinds of paper have acid in them that makes them chemically unstable. Over time, the acid will eat away the text on the page and cause paper to turn yellow or brown and become brittle.  As the acid continues to break down the cellulose fibers, the paper disintegrates.   In the world of philately, the adhesive on the back of stamps is both an inherent vice—any exposure to moisture will compromise their ability to be preserved—as well as the purpose for which the stamps were made.  In the case of film, an example of inherent vice is the innate chemical instability of cellulose acetate film, which can result in the degradation known as "vinegar syndrome" due to the distinctive vinegar odor it produces.

Slowing this tendency of objects to self-destruct requires an understanding of how materials interact. This includes not just an understanding of the intrinsic qualities of the materials themselves, but also the way that they affect and are affected by the other materials that they come into contact with. For example, leather and metal are two materials which are frequently used in combination with each other, but react to each other over time to cause corrosion on the metal.

The presence of deteriorating agents is a problem which can be tempered by selecting archival quality materials, such as acid free paper.  However, frequently the objective of manufacturers is to make a process (i.e. papermaking, book binding, etc.) faster and easier; the longevity of the items they produce is not their primary concern.

Legal definition

The term inherent vice is used in law as well as in library and archival science. One legal definition of inherent vice is "an exclusion found in most property insurance policies eliminating coverage for loss caused by a quality in property that causes it to damage or destroy itself."

Inherent vice can be used as a justification for refusing to insure an item, as its intrinsically self-destructive nature may make it unacceptable risk to a carrier or insurer.

References

External links
 

Preservation (library and archival science)
Spacek SD-1 Minisport. The Spacek SD-1 Minisport is a Czech amateur-built aircraft, designed by Igor Špaček and produced by Spacek of Hodonín. The aircraft was also produced for a short time in the United States by SkyCraft Airplanes of Orem, Utah as a light-sport aircraft, but they had gone out of businesses by 2017. The aircraft is supplied in the form of plans, as a kit for amateur construction, or as a ready-to-fly aircraft.

Design and development
The aircraft features a cantilever low-wing, a single-seat enclosed cockpit, fixed conventional landing gear or optionally tricycle landing gear, a T-tail and a single engine in tractor configuration. Due to its very light weight it can qualify for the German 120 kg category. It complies with the United Kingdom SSDR rules for single seat deregulated microlight aeroplanes.

The aircraft is made from wood, with judicious use of composites, including for the wing spar. Its  span wing employs an A315 airfoil, has an area of  and utilizes flaperons. Engines of  can be used. Standard engines tested are the  Hirth F33, the  Hirth F23 two-strokes, the  or  Briggs & Stratton Vanguard (designated SE24), or the Verner JCV-360 powerplants. The Rotax 447, Hirth 2702, Zanzottera MZ 201, Simonini Victor 1 Super, 2si 460 and Half VW can also be used.

By November 2015 113 had been sold worldwide and about 41 were flying.

At the end of May 2014 SkyCraft Airplanes announced that light-sport flight testing on its version had been completed. Their model has a revised cockpit, including Dynon SkyView instrumentation, a hydraulic brake system and the  Hirth F-23 two-stroke fuel-injected engine. The company's intention was that 12 aircraft would be built for the first production run. However, as of 7 August 2017 the SD-1 was still not on the Federal Aviation Administration's list of accepted light-sport aircraft.

Variants

SD-1 TD
Conventional landing gear (taildragger) version
SD-1 TG
Tricycle gear version
SD-1 TD XL
Conventional landing gear (taildragger) version for taller pilots
SD-1 TG XL
Tricycle gear version for taller pilots
SD-2 SportMaster
 2-seat tricycle gear version

Accidents
 In September 2013, during a test and evaluation flight of the sole example flying in the United States, the pilot lost control while flying aerobatics not approved for the aircraft type and the aircraft crashed. The ballistic parachute did not deploy properly, most likely due to be out of limits for deployment, and the pilot was killed.
 In August 2018, near Nannhausen in Germany, an SD1 crashed after engine problems during climb-out after take-off. The pilot did not survive, the SD1 was written off.
 In June 2021, a loss of control accident happened in Butler, Ohio/USA.  The pilot failed to maintain adequate airspeed following a partial loss of engine power during take-off, which resulted in an aerodynamic stall. The pilot survived, the airplane suffered substantial damage.

Specifications (SD-1)

See also
Similar aircraft
PIK-26
Sonex Aircraft Onex
Corby Starlet
Pazmany PL-4
Mooney M-18 Mite

References

External links

Homebuilt aircraft
Single-engined tractor aircraft
MHW-RTG. The Multihundred-watt radioisotope thermoelectric generator (MHW RTG) is a type of US radioisotope thermoelectric generator (RTG) developed for the Voyager spacecraft, Voyager 1 and Voyager 2. The Voyager generators continue to function more than 45 years into the mission.

Each RTG has a total weight of 37.7 kg, including about 4.5 kg of Pu-238 and uses 24 pressed plutonium-238 oxide spheres to provide enough heat to generate approximately 157 watts of electrical power initially – halving every 87.7 years.

Each RTG initially generated about 2400 watts of thermal power.
Conversion of the decay heat of the plutonium to electrical power uses 312 silicon-germanium
(SiGe) thermoelectric couples. The initial thermoelectric couple hot junction temperature was 1273 K (1000 °C, 1832 °F) with a cold junction temperature of 573 K (300 °C, 572 °F).

Each Voyager spacecraft has 3 RTGs. Collectively, the RTGs supply each Voyager spacecraft with 470 watts at launch.

MHW-RTGs were used on the Lincoln Experimental Satellites 8 and 9.

Subsequent US spacecraft used the GPHS-RTG, which used similar SiGe thermoelectric devices but a different packaging of the fuel.

The MMRTG is a newer RTG type, used on the Curiosity rover.

References

See also
Nuclear power in space

Nuclear power in space
Plutonium
Voyager program