omniomni/omni-engineering huggingface dataset:
Isethionic acid. Isethionic acid is an organosulfur compound containing an alkylsulfonic acid located beta to a hydroxy group. Its discovery is generally attributed to Heinrich Gustav Magnus, who prepared it by the action of solid sulfur trioxide on ethanol in 1833.
It is a white water-soluble solid used in the manufacture of certain surfactants and in the industrial production of taurine. It is most commonly available in the form of its sodium salt (sodium isethionate).

Synthesis
The original synthesis of the compound, involving the reaction of sulfur trioxide with ethanol, has largely been replaced by more advanced methods. An alternative production method involves the hydrolysis of carbyl sulfate, which is derived from the sulfonation of ethylene.

However the most common route is the reaction of ethylene oxide with aqueous sodium bisulfite, which produces the sodium salt (sodium isethionate):

Reactions
Isethionic acid is used as a starting material in the industrial production of taurine.

Dehydration of isethionic acid gives vinylsulfonic acid.

Derivatives
Fatty acid esters of isethionic acid (such as sodium lauroyl isethionate and sodium cocoyl isethionate) are used as biodegradable anionic surfactants. These materials are much milder to skin that other sulfate based surfactants (i.e. sodium lauryl sulfate) making them popular for use in make-up, shampoos and detergent bars including those made by Dove.

Isethionic acid  is also used as a counter ion in certain pharmaceutical formulations, including the antimicrobials hexamidine and pentamidine.

Biological importance
Studies made on dog heart slices suggested that heart tissue may be capable of converting taurine to isethionic acid, further experiments demonstrated that this tissue may synthesize taurine from cystine.

See also
 1,3-Propane sultone
 Ethanedisulfonic acid

References

Sulfonic acids
Primary alcohols
Dielectric reluctance. Dielectric reluctance is a scalar measurement of a passive dielectric circuit (or element within that circuit) dependent on voltage and electric induction flux, and this is determined by deriving the ratio of their amplitudes. The units of dielectric reluctance are F−1 (inverse farads—see daraf) [Ref. 1-3].

As seen above, dielectric reluctance is represented as lowercase z epsilon.
    
For a dielectric in a dielectric circuit to have no energy losses, the imaginary part of its dielectric reluctance is zero. This constitutes a lossless "resistance" to electric induction flux, and is therefore real, not complex. This formality is similar to Ohm's Law for a resistive circuit. In dielectric circuits, a dielectric material has a "lossless" dielectric reluctance equal to:

Where:
 is the circuit length
 is the cross-section of the circuit element
 is the dielectric permeability

See also

Dielectric
Dielectric complex reluctance — General definition of dielectric reluctance that accounts for energy loss

References

 Hippel A. R., Dielectrics and Waves. New York: John Wiley, 1954.
 Popov V. P.,  The Principles of Theory of Circuits. – M.: Higher School, 1985, 496 p. (In Russian).
 Küpfmüller K. Einführung in die theoretische Elektrotechnik, Springer-Verlag, 1959.

Electric and magnetic fields in matter
LAM/MPI. LAM/MPI is one of the predecessors of the Open MPI project.  Open MPI represents a community-driven, next generation implementation of a Message Passing Interface (MPI) fundamentally designed upon a component architecture to make an extremely powerful platform for high-performance computing. LAM/MPI was officially retired in March 2015.

LAM (Local Area Multicomputer) is an MPI programming environment and development system for heterogeneous computers on a network. With LAM/MPI, a dedicated computer cluster or an existing network computing infrastructure can act as a single parallel computing resource.  LAM/MPI is considered to be "cluster friendly", in that it offers daemon-based process startup/control as well as fast client-to-client message passing protocols.  LAM/MPI can use TCP/IP, shared memory, Myrinet (GM), or Infiniband (mVAPI) for message passing.

LAM features a full implementation of MPI-1 and much of MPI-2.  Compliant applications are source code portable between LAM/MPI and any other implementation of MPI.  In addition to providing a high-quality implementation of the MPI standard, LAM/MPI offers extensive monitoring capabilities to support debugging.  Monitoring happens on two levels.  First, LAM/MPI has the hooks to allow a snapshot of process and message status to be taken at any time during an application run.  This snapshot includes all aspects of synchronization plus datatype maps/signatures, communicator group membership, and message contents (see the XMPI application on the main LAM web site).  On the second level, the MPI library is instrumented to produce a cumulative record of communication, which can be visualized either at runtime or post-mortem.

References

External links
Open MPI web site
LAM/MPI web site (no longer works as of September, 28th 2015)
Debugging LAM/MPI applications with shell script wrappers (no longer works as of September, 28th 2015)

Parallel computing
Exosomatic memory. Exosomatic memory is the recording of memories outside the brain. The earliest forms of symbolic behavior—scratching marks on bones—seem to be intended as exosomatic memory. However it was the invention of writing that allowed complex memories to be recorded.

A more narrow meaning of exosomatic memory is a computerized information system that interfaces directly with the brain and functions as an extension of the user memory. Such systems have been used as plot devices in numerous science fiction stories, especially among the cyberpunk genre. More recently, as scientific knowledge of neurology improves, some such as Gregory B. Newby are suggesting that such a device may be possible.

See also
 Brain–computer interface

References

Memory
Operating system abstraction layer. An operating system abstraction layer (OSAL) provides an application programming interface (API) to an abstract operating system making it easier and quicker to develop code for multiple software or hardware platforms. It can make an application less dependent on any one specific operating system.

OS abstraction layers deal with presenting an abstraction of the common system functionality that is offered by any operating system by the means of providing meaningful and easy to use wrapper functions that in turn encapsulate the system functions offered by the OS to which the code needs porting.  A well designed OSAL provides implementations of an API for several real-time operating systems (such as vxWorks, eCos, RTLinux, RTEMS). Implementations may also be provided for non real-time operating systems, allowing the abstracted software to be developed and tested in a developer friendly desktop environment. 

In addition to the OS APIs, the OS abstraction layer project may also provide a hardware abstraction layer, designed to provide a portable interface to hardware devices such as memory, I/O ports, and non-volatile memory. To facilitate the use of these APIs, OSALs generally include a directory structure and build automation (e.g., set of makefiles) to facilitate building a project for a particular OS and hardware platform.

Implementing projects using OSALs allows for development of portable embedded system software that is independent of a particular real-time operating system. It also allows for embedded system software to be developed and tested on desktop workstations, providing a shorter development and debug time.

Implementations 
 TnFOX
 MapuSoft Technologies - provides a commercial OS abstraction implementation allowing software to support multiple RTOS operating systems.
 ClarinoxSoftFrame – middleware which  provides OS abstraction targeting wireless embedded device and system development. It comprises wireless protocol stacks, development tools and memory management techniques in addition to the support of desktop and a range of real-time operating systems
IBM's Rhapsody
 ACE

References

External links
 http://opensource.gsfc.nasa.gov/projects/osal/index.php
 http://osal.sf.net
 https://github.com/nasa/osal
 http://www.clarinox.com/index.php?id=34
 http://ntmio.com/
 https://www.mapusoft.com/mapusoft-os-abstraction-layer/
Operating system technology
Germanium tetrachloride. Germanium tetrachloride is a colourless, fuming liquid with a peculiar, acidic odour. It is used as an intermediate in the production of purified germanium metal. In recent years, GeCl4 usage has increased substantially due to its use as a reagent for fiber optic production.

Production
Most commercial production of germanium is from treating flue-dusts of zinc- and copper-ore smelters, although a significant source is also found in the ash from the combustion of certain types of coal called vitrain. Germanium tetrachloride is an intermediate for the purification of germanium metal or its oxide, GeO2.

Germanium tetrachloride can be generated directly from GeO2 (germanium dioxide) by dissolution of the oxide in concentrated hydrochloric acid. The resulting mixture is fractionally distilled to purify and separate the germanium tetrachloride from other products and impurities. The GeCl4 can be rehydrolysed with deionized water to produce pure GeO2, which is then reduced under hydrogen to produce germanium metal.

Production of GeO2, however, is dependent on the oxidized form of germanium extracted from the ore. Copper-lead-sulfide and zinc-sulfide ores will produce GeS2, which is subsequently oxidized to GeO2 with an oxidizer such as sodium chlorate. Zinc-ores are roasted and sintered and can produce the GeO2 directly. The oxide is then processed as discussed above.

The classic synthesis from chlorine and germanium metal at elevated temperatures is also possible. Additionally,  a chlorine free activation of germanium has been developed, giving a less energy intensive and more environmentally friendly alternative synthesis for germanium precursors.

Application
Germanium tetrachloride is used almost exclusively as an intermediate for several optical processes. GeCl4 can be directly hydrolysed to GeO2, an oxide glass with several unique properties and applications, described below and in linked articles:

Fiber optics
A notable derivative of GeCl4 is germanium dioxide.  In the manufacture of optical fibers, silicon tetrachloride, SiCl4, and germanium tetrachloride, GeCl4, are introduced with oxygen into a hollow glass preform, which is carefully heated to allow for oxidation of the reagents to their respective oxides and formation of a glass mixture. The GeO2 has a high index of refraction, so by varying the flow rate of germanium tetrachloride the overall index of refraction of the optical fiber can be specifically controlled. The GeO2 is about 4% by weight of the glass.

References

See also
 Germanium
 Optical fiber
 Infrared

Germanium(IV) compounds
Chlorides
Metal halides
Nonmetal halides
British Rail Class 103. The British Rail Class 103 diesel multiple units were built by Park Royal Vehicles with diesel engines by British United Traction (BUT).  Ordered in the first half of 1955, 20 of these sets were built by Park Royal at the Crossley Motors works in Stockport of the ACV Group. They consisted of a power car and a driving trailer. Standard BUT equipment was fitted, with 'A' type engines.

A two-car set with 16 first class and 100 second class seats weighed just under 60 long tons, representing 1,150 lb (520 kg) a seat and had 5 hp per ton of empty weight or 4.35 hp per ton when full.

Orders

Operations
They were allocated new to the London Midland Region of British Railways, spending most of their time at Chester. The first deliveries went to traffic in the Llandudno area, allocated to Llandudno Junction in early 1958. This is believed to be an indirect consequence of unit shortages as a result of bogie problems with the BRCW units [Trains Illustrated 1958]. By the end of the same year they were all allocated to Ryecroft for the routes radiating from Walsall. These services were dieselised on 17 November that year [Trains Illustrated Jan 1959 p53]. The last four sets, including W50413 and W56169 the surviving full set, were transferred to the Western Region of British Railways, and worked on the Kingswear Branch having been based out of Laira Depot. Although considered non-standard, owing to their bodywork construction, their use of standard BUT equipment and blue square coupling code allowed them to operate with other classes.

They spent some time in the Watford area, working the St Albans and Belmont branches after the demise of the ACV/BUT "flying brick" railcars. Three units were transferred for this service in December 1958, according to Trains Illustrated [Feb 1959 p110].

Accidents and incidents
On 8 May 1972 an oil train 'ran away' and crashed in Chester General station. M50407 and M56154 were in an adjacent platform and damaged beyond repair.

Liveries
They were delivered in Brunswick green with cream lining, red bufferbeam and pale grey roof. The first sets were delivered without "speed whiskers" (a decorative device on the front). Plain blue with yellow ends was later applied, initially with just a small yellow panel.

Decline
The bodywork became troublesome in service, seeing many withdrawn early. By the end of 1972 there were only 12 power and 14 trailers left in service. The last power car was withdrawn in December 1982, and the last trailer in February 1983.

Preservation
Due to asbestos insulation, only three Class 103 vehicles survive in preservation. 50413 and 56169 are currently being restored by the Helston Railway Diesel Group for use on the Helston branch line. 56160 is privately preserved. Three other vehicles were preserved but have since been scrapped.

References

External links

 The Railcar Association

103
Park Royal Vehicles multiple units
Train-related introductions in 1957
SS Himalaya (1948). SS Himalaya was a British passenger ship of the Peninsular and Oriental Steam Navigation Company, launched in 1948, which operated mainly between Britain and Australia. She was withdrawn from service in 1974 and scrapped the next year.

History

Himalaya was built at Barrow-in-Furness by Vickers-Armstrongs and launched 5 October 1948. She had an identical hull and machinery to the Orient Line's Orcades (yard no. 950 to Himalaya'''s 951), though differing in superstructure and internal layout. She began her service on the Tilbury-Bombay-Australia route in 1949 following her departure from the shipbuilding yard in August. During her commission Himalaya underwent a number of improvements the first of which was, although controversial at the time, a funnel cowl to keep the liner's decks clear of debris without interference to the boilers.

Arthur C. Clarke completed his book, The City and the Stars, on board Himalaya during a voyage to Sydney between September 1954 and  March 1955, as mentioned at the end of the book.

In 1958, she pioneered a new South Pacific route for P&O, from Melbourne and Sydney to San Francisco and Los Angeles via Fiji, Honolulu and Vancouver. The following year, she was routed from Los Angeles to Singapore and then onward to London.

In the winter of 1959-60, she was given a major refit by the Rotterdam Drydock Co., which include the installation of full air  conditioning. In 1963, following the sale of the Strath Class liners by P&O, Himalaya, along with Orcades, was converted to all tourist class and was often used on assisted immigrant sailings.Himalaya arrived at Hong Kong on 31 October 1974 on her final commercial voyage. She was sold to Tong Cheng Steel Manufacturing Co. Ltd, and scrapped in Kaohsiung, Taiwan, in 1975.Himalaya was in a background scene, while docked in Hong Kong, in an episode of the series I Spy Season: 01 Ep: 02. A Cup of Kindness.''

See also

References

External links
 photo gallery
 photo gallery

Ships of P&O (company)
Steam turbine-powered ships
Ships built in Barrow-in-Furness
1948 ships
London Underground D Stock (District Railway). The D Stock was built by Metropolitan Amalgamated Railway Carriage & Wagon in Saltley, England for the District Railway in 1912. A total of thirty cars were built, twenty-two were driving motor cars and eight were trailers. In 1928 the eight trailer cars were rebuilt into motor cars at Acton Works.

These units were very similar to the earlier B and C Stock trains. In the 1940s the C, D and E stocks were reclassified as "H Stock" (signifying hand-operated doors), along with other pre-1938 District Line rolling stock that had not been converted to have air-operated doors. The H Stock was largely eliminated by the early 1950s, following replacement by R Stock. The remaining cars were largely confined to the Olympia shuttle service and were withdrawn from passenger service by the late 1950s. One continued in use for a time in grey livery as a "Stores Carrier" motor car SC637, before being finally broken up in May 1963.
No vehicles have survived into preservation.

References

Metropolitan District Railway
D
Train-related introductions in 1912

Metropolitan Cammell multiple units
London Underground B Stock. The London Underground B Stock was built in 1905 for the District Railway (now the London Underground's District line). 420 vehicles were built, formed into 60 seven-car units.

History
140 cars were built, divided equally between the two suppliers, in Britain by both Brush Traction and Metropolitan Amalgamated Railway Carriage and Wagon Company, with the remaining 280 built in France by Les Ateliers de Construction du Nord de la France. 192 of the cars were driving motors, thirty-two were control trailers and the remaining 196 cars were trailers.

These units were wooden-bodied and were based on the prototype A Stock.

The trailers had wooden underframes as well as wooden bodywork. This proved to be insufficiently robust, resulting in their premature withdrawal. The B Stock motor cars (with steel underframes) were therefore modified as trailers in the early 1920s, the electrical equipment being used for new G Stock motor cars.

As originally built, the B Stock cars had air-operated sliding doors. This proved to be unreliable and was quickly modified to a hand-operated system, with balancing weights. The hand-operated doors could be opened by passengers whilst a train was in motion. This potentially dangerous system remained in use on some District line trains until the late 1950s. The remaining B Stock cars were later reclassified as H Stock. Following their withdrawal (by the mid-1940s) all other remaining District line trains with hand-operated doors were designated as H Stock.

The final cars were withdrawn by the 1940s. Afterwards, at least three cars were transferred into departmental service, being used as a weed killing train. No vehicles have survived into preservation.

References
 

Metropolitan District Railway
B
Train-related introductions in 1905
London Underground A Stock (District Railway). The A Stock cars were built for the District Railway by Brush Traction in 1903. They were the prototype electric units tested by the District Railway.

History
Two seven car, wooden bodied, trains were built by Brush at Loughborough in 1903. Both trains consisted of driving motor cars at either end, a driving motor car centrally placed with four trailer cars elsewhere in the formation. Trains could be split into shorter consists, dependent on the location of the central driving motor. The outer driving motors had a luggage compartment at the driving end behind the driving compartment, and gates for passenger access at the inner end. The centre motor cars had gates at either end and equipment enabling them to be driven from either end and operate as a single vehicle. In addition to the end gates, all cars had centrally located hand operated passenger doors. Each train had differing control and braking systems to compare these systems in service. Later, some trailer cars were equipped with driving controls in a half-cab at one end enabling shorter trains to be operated. These trains were later fitted with Ward couplings, the first to be thus equipped.

Operation 
Originally operating between Mill Hill Park (later renamed Acton Town) and South Harrow, and from 1905 also working between South Acton and Hounslow. The South Harrow shuttle was extended to Uxbridge in 1910.

Fate 
The last car was withdrawn in 1925 and no examples passed to the London Passenger Transport Board.
 
None survived into preservation.

Fleet details

References

External links
 photo of london underground A stock

Metropolitan District Railway
A
Train-related introductions in 1903
The Software Link. The Software Link, Inc. (TSL) was a company in Norcross, Georgia that developed software for personal computers from 1986 to 1994.  The company was co-founded by Rod Roark and Gary Robertson.

Products
 PC-MOS: an MS-DOS-like multiuser operating system with support for multi-tasking on serial terminals;
 PC-MOS/386: a later version of PC-MOS using features not present on processors prior to the 80386;
 LANLINK: a NetBIOS-ready local area network that leverages serial and parallel port connected platforms; and
 MultiLink: a multitasking environment for DOS.

History
PC-MOS figured prominently in the lawsuit Arizona Retail Systems, Inc. v. The Software Link, Inc., where Arizona Retail Systems claimed The Software Link violated implied warranties on PC-MOS. The case is notable because The Software Link argued that it had disclaimed the implied warranties via a license agreement on the software's shrinkwrap licensing. The result of the case, which Arizona Retail Systems won, helped to establish US legal precedent about the enforceability or otherwise of shrinkwrap licensing.

References

Defunct software companies of the United States
Software companies established in 1984
Software companies disestablished in 1997