omniomni/omni-engineering huggingface dataset:
Tumansky RD-9. The Tumansky RD-9 (initially designated Mikulin AM-5) was an early Soviet turbojet engine, not based on pre-existing German or British designs. The AM-5, developed by scaling down the AM-3, was available in 1952 and completed testing in 1953; it produced   thrust without afterburner. The AM-5 engine is notable for making possible the first mass-produced supersonic interceptors such as the MiG-19, and the first Soviet all-weather area interceptor, the Yak-25. When Sergei Tumansky replaced Alexander Mikulin as the OKB-24's chief designer in 1956, the engine was renamed RD-9. The engine was later built under license in China as the WP-6.

Variants and applications

RD-9A
RD-9B Used in the East German civilian jetliner project Baade 152 in 1958 and 1959, replaced when Pirna 014 engines became available.
RD-9AK Non-afterburning versions for the Yak-25 and Yak-26.
RD-9AF-300 Afterburning version for the Yak-27 and Yak-28.
RD-9AF2-300 Afterburning version for the Yak-27 and Yak-28.
RD-9B Afterburning version for the early variants of MiG-19.
RD-9BK Version for Lavochkin La-17M.
RD-9BF-811 Afterburning version for the later variants of MiG-19.
RD-9V Afterburning version used in the Ilyushin Il-40P. 
WP-6 Chinese built version for the Shenyang J-6.
WP-6A a Chinese upgraded version for the Nanchang Q-5 and J-6C.
WP-6Z further developed for the cancelled Nanchang J-12
NK-TJ North Korean version built for MiG-19 and Shenyang J-6

Specifications (RD-9BF-811)

See also

Notes

See also
Soyuz Scientific Production Association

References

 The Osprey Encyclopedia of Russian Aircraft: 1875-1995, Bill Gunston, .

External links

 RD-9B page on LeteckeMotory.cz (cs)

Tumansky aircraft engines
1950s turbojet engines
Klimov VK-1. The Klimov VK-1 was the first Soviet jet engine to see significant production. It was developed by  and first produced by the GAZ 116 works. Derived from the Rolls-Royce Nene, the engine was also built under licence in China as the Wopen WP-5.

Design and development

Immediately after World War II, the Soviet Union manufactured copies of first generation German Junkers 004 and BMW 003 engines, which were advanced designs with poor durability, limited by Germany's shortage of rare metals in wartime. However, in 1946, before the Cold War had really begun, the new British Labour government under the prime minister, Clement Attlee, keen to improve diplomatic relations with the Soviet Union, authorised Rolls-Royce to export 40 Rolls-Royce Nene centrifugal flow turbojet engines. In 1958 it was discovered during a visit to Beijing by Whitney Straight, then deputy chairman of Rolls-Royce, that this engine had been copied without license to power the MiG-15 'Fagot', first as the RD-45, and after initial problems of metallurgy forced the Soviet engineers to develop a slightly redesigned (and metallurgically closer) copy, the engine had then entered production as the Klimov VK-1 (Rolls-Royce later attempted to claim £207m in license fees, without success).

The RD-45 was improved to produce the VK-1, which differed from the Nene in having larger combustion chambers, a larger turbine, and revised induction giving greater airflow through the engine, raised from 41 kg/s for the Nene, to 45 kg/s.  The VK-1F model added the afterburner.

The engine featured a centrifugal compressor, requiring a larger-diameter fuselage than aircraft featuring axial compressor designs that had already appeared during World War II in Germany and Britain.

Applications
The VK-1 was used to power the MiG-15 'Fagot' and MiG-17 'Fresco' fighters and the Il-28 'Beagle' bomber. Some of these engines are in use today in Russia mounted on trucks and railroad cars as snow blowers and ice melters.

Specifications (VK-1)

See also
 List of aircraft engines

References

Notes

Bibliography

 Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989.

External links

 VK-1 on LeteckeMotory.cz (czech)
 VK-1F on LeteckeMotory.cz (czech)
 Engine number 5-6, 2000 (ru)

1940s turbojet engines
VK-1
Centrifugal-flow turbojet engines
Products introduced in 1947
Thermal velocity. Thermal velocity or thermal speed is a typical velocity of the thermal motion of particles that make up a gas, liquid, etc. Thus, indirectly, thermal velocity is a measure of temperature. Technically speaking, it is a measure of the width of the peak in the Maxwell–Boltzmann particle velocity distribution. Note that in the strictest sense thermal velocity is not a velocity, since velocity usually describes a vector rather than simply a scalar speed.

Since the thermal velocity is only a "typical" velocity, a number of different definitions can be and are used.

Taking  to be the Boltzmann constant,  the absolute temperature, and  the mass of a particle, we can write the different thermal velocities:

In one dimension 

If  is defined as the root mean square of the velocity in any one dimension (i.e. any single direction), then

If  is defined as the mean of the magnitude of the velocity in any one dimension (i.e. any single direction), then

In three dimensions 

If  is defined as the most probable speed, then

If  is defined as the root mean square of the total velocity, then

If  is defined as the mean of the magnitude of the velocity of the atoms or molecules, then

All of these definitions are in the range

Thermal velocity at room temperature

At 20 °C (293.15 kelvins), the mean  thermal velocity of common gasses in three dimensions is:

References

Thermodynamic properties
Statistical mechanics
RC flight simulator. An RC flight simulator is a computer program that allows pilots of radio-controlled aircraft to practice on a computer, without the risk and expense of damaging a real model. Besides the obvious use of training beginners, they are also used for practising new aerobatics, evaluating a model before buying it, and to allow flight practice when conditions are otherwise unsuitable.  Most simulators allow the use of real R/C transmitters to control the sim.

There are a number of commercial packages available, such as Eiperle CGM's neXt - RC Flight Simulator, SVK Systems' ClearView, Knife Edge Software's RealFlight, IPACS' AeroFly and Trasna Technology's AccuRC. There are also a number of free simulators, with FS One being the most well known and most feature rich.

Most simulators allow the importing of add-ons such as new models and landscapes. There are many web sites dedicated to offering free content like this.

Some of these simulators are dedicated to R/C flight, while others are generic simulators that can simulate both full-scale and R/C flight.

Feature Comparison

References

External links 
 Forum - RC-Sim.de, the RC-Simulation Server

Radio-controlled aircraft
Bremen-class frigate. The eight F122 Bremen-class frigates of the German Navy was a series of frigates commissioned between 1982 and 1990. The design was based on the proven and robust Dutch  but used a different propulsion system and hangar lay-out. The ships were built for anti-submarine warfare as a primary task although they were not fitted with towed array sonars. They were also equipped for anti-surface warfare, while having anti-aircraft warfare point defences.

This class of ship was one of the last to be constructed under post-war displacement limitations imposed by the WEU on West Germany.

All eight Bremen-class frigates were replaced by the . Prior to that the Bremen class served as the backbone of the German Navy.

Employment 
During the Cold War period, the ships' main war task was to escort convoys for reinforcement and resupply of allied forces in Europe in the Northern Atlantic. They frequently took part in NATO Standing Naval Forces. Since 1990, all ships have served in additional supporting missions such as the embargo operations against former Yugoslavia in the Adriatic Sea or Operation Enduring Freedom against the international terrorism.

During their lifetime, the ships' equipment has frequently been modernized and proven to be reliable platforms.

Notable actions

Karlsruhe successfully assisted an Egyptian freighter repel pirates on 25 December 2008 in the Gulf of Aden.

In 2012 Rheinland-Pfalz was reportedly used to gather intelligence on Syrian troop movements to be passed to the Free Syrian Army assist in their attacks on the Syrian Army.

In December 2015 Augsburg joined the French aircraft carrier  in the south-eastern Mediterranean Sea to go to the Arabian Sea as part of the intervention against ISIS in the Syrian Civil War.

Ships

All ships were based in Wilhelmshaven. Together they formed the 4. Fregattengeschwader (4th Frigate Squadron) of the German Navy.

Gallery

See also
List of frigate classes
List of German Federal Navy ships
List of naval ship classes of Germany

References

Sources
 Website for all active and retired Frigate F213 Seamen
 
 naval-technology.com
 https://www.nytimes.com/2008/12/26/world/africa/26pirates.html?ref=world
 http://news.bbc.co.uk/2/hi/africa/7799796.stm

External links 
 

 
 
German involvement in the Syrian civil war
Frigate classes
CommSuite 95. CommSuite 95 is a communications software suite launched in 1995 by Canadian software company Delrina.

History
Beta testing started in August 1995. CommSuite 95 was a collection of 32-bit programs created specifically for use with Windows 95. It included WinFax PRO 7.0 (computer fax software), along with WinComm PRO 7.0 (online communications), TalkWorks (a voice mail application), and the Cyberjack suite of Internet components. A beta of Cyberjack 7.0 web browser was available early October 1995 for a free trial download.

It was the last official release issued under the Delrina brand. The company was bought out by Symantec the month before the suite's release in November 1995.

Features 

CommSuite offered features such as 32-bit components compatible with Windows 95 and MS Office, support for OLE 2.0, messaging API and Telephony Application Programming Interface. WinComm Pro provided virus protection. CommBar module offered status reporting and easy access to all components.

Reception 
The software was well received, with PC/Computing preview highlighting CommSuite 95 as the first package to integrate fax, e-mail, voice mail and web browsing seamlessly under Windows 95. However, some deficiencies were noted. A PC Magazine "first look article reported performance problems on systems with less than 16 MB RAM and issues with Cyberjack, which was displayed many pages incorrectly. InfoWorld review lauded features like 32 bit access, multitasking, multithreading and OLE 2.0 support, but criticized high disk space requirements and installation problems; (the reviewer was forced to install applications separately). The target market was thought to be unclear, as many people would likely be content with Windows services.

References

Windows-only proprietary software
Delrina software
Electron donor. In chemistry, an electron donor is a chemical entity that transfers electrons to another compound. It is a reducing agent that, by virtue of its donating electrons, is itself oxidized in the process.  An obsolete definition equated an electron donor and a Lewis base.

In contrast to traditional reducing agents, electron transfer from a donor to an electron acceptor may be only fractional. The electron is not completely transferred, which results in an electron resonance between the donor and acceptor. This leads to the formation of charge transfer complexes, in which the components largely retain their chemical identities. The electron donating power of a donor molecule is measured by its ionization potential, which is the energy required to remove an electron from the highest occupied molecular orbital (HOMO).

The overall energy balance (ΔE), i.e., energy gained or lost, in an electron donor-acceptor transfer is determined by the difference between the acceptor's electron affinity (A) and the ionization potential (I):

Molecular electronics and devices

Electron donors are components of many devices such as organic photovoltaic devices.  Typical electron donors undergo reversible redox so that they can serve as electron relays. Triarylamines are typical donors.

In biology 
NADH is an example of a natural electron donor.  Ascorbic acid is another example.  It is a water-soluble antioxidant.

In biology, electron donors release an electron during cellular respiration, resulting in the release of energy. Microorganisms, such as bacteria, obtain energy in electron transfer processes. Through its cellular machinery, the microorganism collects the energy for its use. The final result of this process (electron transport chain) is an electron being donated to an electron acceptor. Petroleum hydrocarbons, less chlorinated solvents like vinyl chloride, soil organic matter, and reduced inorganic compounds are all compounds that can act as electron donors. These reactions are of interest not only because they allow organisms to obtain energy, but also because they are involved in the natural biodegradation of organic contaminants. When clean-up professionals use monitored natural attenuation to clean up contaminated sites, biodegradation is one of the major contributing processes.

See also
Semiconductor
Donor (semiconductors)

References

Electrochemical concepts

ru:Донор (физика)
Electron acceptor. An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. Electron acceptors are oxidizing agents.

The electron accepting power of an electron acceptor is measured by its redox potential.

In the simplest case, electron acceptors are reduced by one electron.  The process can alter the structure of the acceptor substantially. When the added electron is highly delocalized, the structural consequences of the reduction can be subtle. The central C-C distance in the electron acceptor tetracyanoethylene elongates from 135 to 143 pm upon acceptance of an electron.  In the formation of some donor-acceptor complexes, less than one electron is transferred.  TTF-TCNQ is a charge transfer complex.

Biology

In biology, a terminal electron acceptor  often refers to either the last compound to receive an electron in an electron transport chain, such as oxygen during cellular respiration, or the last cofactor to receive an electron within the electron transfer domain of a reaction center during photosynthesis.  All organisms obtain energy by transferring electrons from an electron donor to an electron acceptor.

One practical illustration of the role of electron acceptors in biology is the high toxicity of the paraquat.  The activity of this broad spectrum herbicide results from the electron acceptor property of N,N'-dimethyl-4,4'-bipyridinium.

Materials science
In some solar cells, the photocurrent entails transfer of electrons from a donor to an electron acceptor.

See also
 Acceptor (semiconductors)
 Redox reaction
 Semiconductor

References

External links
 Electron acceptor definition at United States Geological Survey website
 Environmental Protection Agency

Electrochemical concepts
Connellite. Connellite is a rare mineral species, a hydrous copper chloro-sulfate, Cu19(OH)32(SO4)Cl4·3H2O, crystallizing in the hexagonal system. It occurs as tufts of very delicate acicular crystals of a fine blue color, and is associated with other copper minerals of secondary origin, such as cuprite and malachite. Its occurrence in Cornwall, England, was noted by Philip Rashleigh in 1802, and it was first examined chemically by Prof Arthur Connell FRSE in 1847, after whom it is named.

The type locality is Wheal Providence at Carbis Bay in Cornwall. Outside Cornwall it has been found in over 200 locations worldwide including Namaqualand in South Africa and at Bisbee, Arizona (US).

References

Copper(II) minerals
Halide minerals
Sulfate minerals
Hexagonal minerals
Minerals in space group 194
British Rail Class 117. The British Rail Class 117 diesel multiple units (DMUs) were built by Pressed Steel from 1959 to 1961. It was a licence-built variant of the British Rail Class 116.

Original work
A total of 123 Class 117 cars were built by Pressed Steel between 1959 and 1961, delivered as 39 three-car units plus three pairs of spare motor coaches.  When first introduced in 1960, these three-car units were all based with the similar Class 121 single carriage (railcar) units on British Railways Western Region for suburban work out of London Paddington. The units were largely based at Reading and Southall depots. The units remained here for many years working these services.

The type was used for a railtour from Paddington to the south west on 31 May 1969.

Later operations
In the 1980s, expiry of other DMUs facilitated moves for some units from the Western Region to Birmingham, as below, and Scotland, prior to the delivery of new units to replace them. They were given refurbishments.

The first shake up in ownership occurred in the late 1980s, when the Scottish, Welsh, Cornish and Birmingham based units were transferred to Provincial Services, later Regional Railways, in the sectorisation of British Rail, while the Southall-based units transferred to Network SouthEast.

They were replaced on the lines out of Paddington when the Class 165/1 'Network Turbo' units came into service by 28 November 1992.

They soldiered on in the former Western Region until replaced by Class 150 and Class 153 DMUs by 21 May 1993, although the type could be found running Penzance - Looe services until 1997. An attempt was made to remove them from Cornish work using Class 142 "Skipper/Pacer" railcars, but these fixed wheelbase units proved to be a liability on the tight Cornish branchline curves, increasing rail and wheel wear, and were transferred to the North of England instead. The 117s were finally replaced with the advent of more Class 150s and Class 153s freed up from other areas.

The type was used in Scotland between Edinburgh - Perth, Cowdenbeath and Markinch using the Forth Bridge and continued to work in Scotland until 12 January 1998, where they were replaced with Class 156s. The final day of 117s running in Scotland was 27 November 1999.

In 2000, Class 150 Sprinter units replaced the Class 117 units on Silverlink, finally bringing to an end decades of service on Britain's rail network in front line service.

Preservation
Due to the type's longevity, 12 units have been preserved on heritage railways.

References

Bibliography

Further reading

External links

The Railcar Association

117
Pressed Steel Company multiple units
Train-related introductions in 1959
Bluing (fabric). Bluing, laundry blue, dolly blue or washing blue is a household product used to improve the appearance of textiles, especially white fabrics. Used during laundering, it adds a trace of blue dye (often synthetic ultramarine, sometimes Prussian blue) to the fabric.

Uses 

White fabrics acquire a slight color cast after use (usually grey or yellow). Since blue and yellow are complementary colors in the subtractive color model of color perception, adding a trace of blue color to the slightly off-white color of these fabrics makes them appear whiter.  Laundry detergents may also use fluorescing agents to similar effect. Many white fabrics are blued during manufacturing. Bluing is not permanent and rinses out over time leaving dingy or yellowed whites. A commercial bluing product allows the consumer to add the bluing back into the fabric to restore whiteness.

On the same principle, bluing is sometimes used by white-haired people in a blue rinse.

Bluing has other miscellaneous household uses, including as an ingredient in rock crystal "gardens" (whereby a porous item is placed in a salt solution, the solution then precipitating out as crystals), and to improve the appearance of swimming-pool water. In Australia it was used as a folk remedy to relieve the itching of mosquito and sand fly bites.

Laundry bluing is made of a colloid of ferric ferrocyanide (blue iron salt, also referred to as "Prussian blue") in water. 

Blue colorings have been added to rinse water for centuries, first in the form of powder blue or smalt, or using small lumps of indigo and starch, called stone blue. After the invention of synthetic ultramarine and Prussian blue it was manufactured by many companies, including Mrs. Stewart's Bluing in the United States, and by Reckitt's Crown Blue in Hull and the Lancashire Ultramarine Company's Dolly Blue at Backbarrow (later purchased by Reckitt & Sons) in the United Kingdom.  It was popular until the mid-twentieth century in the United Kingdom and the United States, and is still widely used in India and Pakistan.  In many places, it has been replaced by bleach for its primary purpose.

Bluing is usually sold in liquid form, but it may also be a solid.  Solid bluing is sometimes used by hoodoo doctors to provide the blue color needed for "mojo hands" without having to use the toxic compound copper(II) sulfate.  Bluing was also used by some Native American tribes to mark their arrows showing tribe ownership.

See also 
Mrs. Stewart's Bluing
Blue rinse
Optical brightener

References

External links 
 Laundry Blue: Bluing, Reckitt's blue bags, Dolly Blue
 Azurage du linge en France

Videos 
 

Cleaning products
Dyes
Alumel. Alumel is an alloy consisting of approximately 95% nickel, 2% aluminium, 2% manganese, and 1% silicon. This magnetic alloy is used to make the negative conductors of ANSI Type K (chromel-alumel) thermocouples and thermocouple extension wire. Alumel is a registered trademark of Concept Alloys, Inc.

References

External links
  Application guide and material properties of thermocouple wires (via Omega Engineering, Inc).

Nickel alloys
Aluminium alloys
Murexide. Murexide (NH4C8H4N5O6, or C8H5N5O6·NH3), also called ammonium purpurate or MX, is the ammonium salt of purpuric acid. It is a purple solid that is soluble in water.  The compound was once used as an indicator reagent. Aqueous solutions are yellow at low pH, reddish-purple in weakly acidic solutions, and blue-purple in alkaline solutions.

Preparation
Murexide is prepared by treating alloxantin with ammonia to 100 °C, or by treating uramil (5-aminobarbituric acid) with mercury oxide. It may also be prepared by digesting alloxan with alcoholic ammonia.

History
Justus von Liebig and Friedrich Wöhler in Giessen, Germany, had investigated the purple product, murexide, obtained from snake excrement in the 1830s, but this was not an abundant raw material, and a method of using it as a dyestuff was not established at that time. In the 1850s, French colourists and dye-producers, such as Depoully in Paris, succeeded in making murexide from abundant South American guano and of applying it to natural fibres. It was then widely adopted in Britain, France and Germany.

Use

Murexide is used in analytical chemistry as a complexometric indicator for complexometric titrations, most often of calcium ions, but also for copper, nickel, cobalt, thorium and rare-earth metals. It functions as a tridentate ligand.

Its use has been eclipsed by calcium-ion selective electrodes.

References

Ammonium compounds
Complexometric indicators
Dyes
Pyrimidines
Lactams
Enones
Dielectric breakdown model. Dielectric breakdown model (DBM) is a macroscopic mathematical model combining the diffusion-limited aggregation model with electric field. It was developed by Niemeyer, Pietronero, and Weismann in 1984. It describes the patterns of dielectric breakdown of solids, liquids, and even gases, explaining the formation of the branching, self-similar Lichtenberg figures.

See also 

 Eden growth model
 Lichtenberg figure
 Diffusion-limited aggregation

References

External links
 Dielectric Breakdown Model

Electricity
Mathematical modeling
Electrical breakdown