omniomni/omni-engineering huggingface dataset:
Class A. Class A may refer to:

Communications technology
 Class-A amplifier, a category of electronic amplifier
 Class A network, in Internet technology, a type of large network
 Class A television service, a system for regulating low power stations in the United States

Sports
 Class A (baseball), a level of American Minor League Baseball
 Class A (classification), a Paralympic wheelchair fencing classification

Transportation
 Class A airfield, a type of World War II British military installation
 Class A surface, in automotive design
 Milwaukee Road class A, a class of steam locomotives
 Norfolk and Western Railway class A, a class of steam locomotives
 Class A, a type of commercial driver's license in the United States
 Class A, an ICAO airspace class
 Class A, a type of motorhome

Other uses
 Class A (novel), a 2004 CHERUB novel by Robert Muchamore
 Class A drug, a classification of drugs controlled by the UK Misuse of Drugs Act
 Class A office space, a Building Owners and Managers Association category
 Library of Congress Classification:Class A -- General Works
 Class A, a stellar classification
 Class A, a retired type of United States Army Service Uniform
 Class A foams, a type of foam used in firefighting

See also 
 A class (disambiguation)
 Class B (disambiguation)
USS Tucson (SSN-770). USS Tucson (SSN-770), a , was the second ship of the United States Navy to be named for Tucson, Arizona. The contract to build her was awarded to Newport News Shipbuilding and Dry Dock Company in Newport News, Virginia on 10 June 1988 and her keel was laid down on 15 August 1991. She was launched on 20 March 1994 sponsored by Mrs. Diane C. Kent.

History
Tucson was originally supposed to be commissioned on 18 August 1995, however, Hurricane Felix threatened the Virginian coastline, and the U.S. Navy decided to sortie the fleet, to prevent damage to ships in port if the hurricane made landfall. Tucson was the last ship to leave port, in case the prediction for landfall changed. As it turned out, the hurricane never did make landfall, but Tucson was at sea on 18 August. Upon returning to port, the commissioning ceremony was quickly rescheduled for 19 September 1995. At the new commissioning ceremony, the commanding officer, Commander Duane M. Baker, declared that for the next two hours, it was officially 18 August.

In June 1996, Tucson was struck by the Military Sealift Command vehicle cargo ship  while moored in port at Newport News. A sudden windstorm caused Gilliland to break free from her mooring and cross the harbor, colliding with Tucson and the destroyer  moored behind her. While Deyo suffered the most damage, Tucson suffered minor damage to her AN/BRA-34 antenna.

From September 1996 to October 1996, Tucson changed her home port. Tucson left Norfolk, Virginia, passed through the Panama Canal and stopped in San Diego, California for five days. VIPs from Tucson, Arizona, were allowed to ride on three separate short cruises, and then busloads of tourists from the city of Tucson came for tours of the submarine while in port. Following this port visit, Tucson continued on to arrive in Pearl Harbor, Hawaii.

Tucson left for her first deployment ever, to the Western Pacific Ocean, in February 1998. At that time, tensions between the United Nations and Iraq had escalated drastically. In the 30 days leading up to departure, the government of Iraq had blocked access to the United Nations Special Commission (UNSCOM) and had withdrawn cooperation with the UNSCOM monitoring teams. The ship traveled as far west as the Persian Gulf before returning to Pearl Harbor in August 1998. It was during this period of time that the PBS series Nova filmed the episode "Battlegroups" aboard Tucson.

On 19 May 2004, Tucson departed for a Western Pacific deployment.

References 

Los Angeles-class submarines
Nuclear submarines of the United States Navy
United States submarine accidents
Cold War submarines of the United States
Maritime incidents in 1996
Ships built in Newport News, Virginia
1994 ships
Submarines of the United States
Class E. Class E may refer to:

Science and technology
 Class E amplifier, a power amplifier class in electronics
 Class E addresses, in a classful network, a type of Internet Protocol IP address
 Class E, twisted pair structured cabling system in the ISO/IEC 11801 standard

Other uses
 Class E, an airspace class as defined by the ICAO
 Class E, a driver's license
 Class E felony, a category of crime in the US

See also

 E class (disambiguation)
 Class (disambiguation)
 E (disambiguation)
 E-Type (disambiguation)
 Model E (disambiguation)
Thermal cycler. The thermal cycler (also known as a thermocycler, PCR machine or DNA amplifier) is a laboratory apparatus most commonly used to amplify segments of DNA via the polymerase chain reaction (PCR). Thermal cyclers may also be used in laboratories to facilitate other temperature-sensitive reactions, including restriction enzyme digestion or rapid diagnostics.  The device has a thermal block with holes where tubes holding the reaction mixtures can be inserted.  The cycler then raises and lowers the temperature of the block in discrete, pre-programmed steps.

History

The earliest thermal cyclers were designed for use with the Klenow fragment of DNA polymerase I.  Since this enzyme is destroyed during each heating step of the amplification process, new enzyme had to be added every cycle.  This led to a cumbersome machine based on an automated pipettor, with open reaction tubes.  Later, the PCR process was adapted to the use of thermostable DNA polymerase from Thermus aquaticus, which greatly simplified the design of the thermal cycler. While in some old machines the block is submerged in an oil bath to control temperature, in modern PCR machines a Peltier element is commonly used. Quality thermal cyclers often contain silver blocks to achieve fast temperature changes and uniform temperature throughout the block. Other cyclers have multiple blocks with high heat capacity, each of which is kept at a constant temperature, and the reaction tubes are moved between them by means of an automated process. Miniaturized thermal cyclers have been created in which the reaction mixture moves via channel through hot and cold zones on a microfluidic chip. Thermal cyclers designed for quantitative PCR have optical systems which enable fluorescence to be monitored during reaction cycling.

Modern innovation
Modern thermal cyclers are equipped with a heated lid that presses against the lids of the reaction tubes. This prevents condensation of water from the reaction mixtures on the insides of the lids. Traditionally, a layer of mineral oil was used for this purpose. Some thermal cyclers are equipped with a fully adjustable heated lid to allow for nonstandard or diverse types of PCR plasticware.

Some thermal cyclers are equipped with multiple blocks allowing several different PCRs to be carried out simultaneously.  Some models also have a gradient function to allow for different temperatures in different parts of the block.  This is particularly useful when testing suitable annealing temperatures for PCR primers.

References

External links
OpenPCR, an open-source PCR thermal cycler

Molecular biology laboratory equipment
Polymerase chain reaction
Columbia (supercomputer). Columbia was a supercomputer built by Silicon Graphics (SGI) for the National Aeronautics and Space Administration (NASA), installed in 2004 at the NASA Advanced Supercomputing (NAS) facility located at Moffett Field in California. Named in honor of the crew who died in the Space Shuttle Columbia disaster, it increased NASA's supercomputing capacity ten-fold for the agency's science, aeronautics and exploration programs.

Missions run on Columbia include high-fidelity simulations of the Space Shuttle vehicle and launch systems, hurricane track prediction, global ocean circulation, and the physics of supernova detonations.

History
Columbia debuted as the second most powerful supercomputer on the TOP500 list in November 2004 at a LINPACK rating of 51.87 teraflops, or 51.87 trillion floating point calculations per second. By June 2007 it had dropped to 13th.

It was originally composed of 20 interconnected SGI Altix 3700 512-processor multi-rack systems running SUSE Linux Enterprise, using Intel Itanium 2 Montecito and Montvale processors.  In 2006, NASA and SGI added four new Altix 4700 nodes containing 256 dual-core processors, which decreased the physical footprint and the power cost of the supercomputer. The nodes were connected with InfiniBand single and double data rate (SDR and DDR) cabling with transfer speeds of up to 10 gigabits per second.

The SGI Altix platform was selected due to a positive experience with Kalpana, a single-node Altix 512-CPU system built and operated by NASA and SGI and named after Columbia astronaut Kalpana Chawla, the first Indian-born woman to fly in space. Kalpana was later integrated into the Columbia supercomputer system as the first node of twenty.

At its peak, Columbia had a total of 10,240 processors and 20 terabytes of memory, 440 terabytes of online storage utilizing SGI's CXFS filesystem, and 10 petabytes of archival tape storage. The Project Columbia team, composed mostly of computer scientists and engineers from NAS, SGI, and Intel, were awarded the Government Computer News (GCN) Agency Award for Innovation in 2005 for deploying Columbia's original 10,240 processors in an unprecedented 120 days.

It was slowly phased out as its successors at NAS, the petascale Pleiades supercomputer and the Endeavour shared-memory system, expanded to meet with NASA's growing high-end computing needs. At the time of its decommissioning in March 2013, Columbia was made up of four nodes over 40 SGI Altix 4700 racks, containing Intel Itanium 2 Montecito and Montvale processors to make up a total of 4,608 cores with a theoretical peak of 30 teraflops and total memory of 9 terabytes.

References

External links 

TOP500 Official Website
TOP500 Columbia System entry
2004 Press release from SGI

NASA supercomputers
Ames Research Center
SGI supercomputers
One-of-a-kind computers
Very long instruction word computing
Birch–Murnaghan equation of state. The Birch–Murnaghan isothermal equation of state, published in 1947 by Albert Francis Birch of Harvard, is a relationship between the volume of a body and the pressure to which it is subjected. Birch proposed this equation based on the work of Francis Dominic Murnaghan of Johns Hopkins University published in 1944, so that the equation is named in honor of both scientists.

Expressions for the equation of state 
The third-order Birch–Murnaghan isothermal equation of state is given by

where P is the pressure, V0 is the reference volume, V is the deformed volume, B0 is the bulk modulus, and B0' is the derivative of the bulk modulus with respect to pressure.  The bulk modulus and its derivative are usually obtained from fits to experimental data and are defined as

and

The expression for the equation of state is obtained by expanding the Helmholtz free energy in powers of the finite strain parameter f, defined as

in the form of a series.
This is more evident by writing the equation in terms of f.  Expanded to third order in finite strain, the equation reads,

with .

The internal energy, , is found by integration of the pressure:

See also
Albert Francis Birch
Francis Dominic Murnaghan
Murnaghan equation of state

References 

Continuum mechanics
Eponymous equations of physics
Equations of state
Bengt Nölting. Bengt Nölting (1 May 1962 – 16 September 2009) was a German physicist and biophysicist who pioneered various methods in biophysics and engineering. Achievements include studying biological macromolecules, the development of self-evolving computer programs, and the development new energy technologies. From 1994–1997 Nölting was scientist at Cambridge University and the Cambridge Centre for Protein Engineering (UK) where he developed, together with Sir Alan R. Fersht, methods for the high resolution of protein folding.

Works

References

1962 births
2009 deaths
21st-century German physicists
20th-century German physicists
Solipsis. Solipsis is a free and open-source system for a massively multi-participant shared virtual world designed by Joaquin Keller and Gwendal Simon at France Télécom Research and Development Labs. It aims to provide the infrastructure for a metaverse-like public virtual territory. Relying on peer-to-peer architecture, the virtual world may potentially be inhabited by a theoretically unlimited number of participants.

Motivations
A central objective of Solipsis is to create a virtual world which is as independent as possible from the influence of private interests, such as server ownership.  In order to achieve this, it is based around a peer-to-peer model rather than the traditional server-client one.  Additionally, it aims to give users more flexibility in designing interfaces and content in their individual segments of the virtual world.

Main principles
A Solipsis entity is a basic element of the virtual world. To exist, an entity should run a node that may be controlled by a navigator.  Nodes are self-organized in a pure peer-to-peer network, in which relationships depend on virtual proximity. A navigator is mainly a graphical user interface, but some communication services may be added to one for interaction between entities.

The virtual world is initially empty and is only filled by entities run by end users' computers.  All Solipsis nodes are functionally equal, and no preordained infrastructure is required.  This eliminates as far as possible any restrictions on the content or functionality of the world.

Current status
Solipsis currently consists of:
A peer-to-peer protocol over UDP.  The Solipsis protocol gives a node the ability to broadcast its presence within the virtual world.  Moreover, this protocol aims to guarantee the maintenance of some global properties.
A node-navigator interface, which takes the form of an API between the node and the navigator.  Currently written in XML-RPC, this interface allows a navigator to control a node and to retrieve information on its virtual surroundings.
A basic implementation of a Solipsis node and a Solipsis navigator licensed under the LGPL. The navigator features a two-dimensional representation of the virtual world.  The design of current interface resembles YackPack, an interactive system developed by the company of the same name, by a team of engineers in Santa Rosa, led by Chief Technology Officer David Levine and envisioned by Professor BJ Fogg of Stanford University.  Interaction between entities consists only of chat.
Some other services, which implement blogs, some identity fields for social networking, file sharing, and graphical chat.

See also

 Snow Crash
 OSMP
 Croquet project
 Second Life

References

External links
 Solipsis Homepage
 
 Toward a Peer-to-Peer Shared Virtual Reality, paper by Joaquin Keller and Gwendal Simon
 A Virtual World With Peer-to-Peer Style, CNet
 Gamers to rule their own virtual worlds, New Scientist
 Gamers Eye Open Virtual Worlds, Wired

File sharing
Orange S.A.
Open-source video games
Online chat
Video games developed in France
Virtual world communities
Inactive massively multiplayer online games
Mailx. mailx is a Unix utility program for sending and receiving mail, also known as a Mail User Agent program. Being a console application with a command syntax similar to ed, it is the POSIX standardized variant of the Berkeley Mail utility.

See also 
 mail (Unix)

References

External links 
 
 History of mail and mailx from the Heirloom Project
 mailx Tutorial from the engineering Dpt. at Purdue University
  at GNU Mailutils manual
 S-nail  manual

Unix SUS2008 utilities
Email client software for Linux
Unix Internet software
Free email software
Console applications
Software using the BSD license
Birmabright. Birmabright is a trade name of the former Birmetals Co. (Birmabright works in Clapgate Lane, Quinton, Birmingham, UK) for various types of lightweight sheet metal in an aluminium–magnesium alloy. The alloy was introduced by the Birmid Group in 1929 and was particularly noted for its corrosion resistance. Birmal Boats was created in 1930 for the building of light-alloy boats. Birmetals Ltd was formed in 1936 and during the war produced both copper bearing aluminium alloys and the Birmabright magnesium bearing alloys, mainly for aircraft production.

The constituents were from 1% to 7% magnesium, with <1% manganese, and the remainder aluminium. The alloys were provided in different temper conditions. e.g. soft, 1/4 hard, 1/2 hard and were designed to be work hardened e.g. by cold pressing into shape. They do not exhibit age hardening, or have a precipitation heat treatment to promote hardening (unlike other contemporary aluminium alloys such as Duralumin). Weldability is good but machinability is only fair to poor. The alloy has good seawater corrosion resistance (unlike Duralumin). 

Birmetals Ltd Birmabright grades included the following : 

The Birmabright designations are obsolete, but equivalent grades exist, for example BB2 equivalent specifications are British standard NS4, American 5251 and ISO designation AlMg2. 

Gas welding of Birmabright is easier than that of pure aluminium and may be carried out autogenously using scraps of the same material as a filler rod. 

Birmabright is best known as the material used in the body of the Land Rover from its launch in April 1948, and in a few other classic British vehicles. The doors, boot lid and bonnet of most Rover P4 models were also Birmabright, however towards the end of production this was changed to steel to reduce costs. An early use in the 1930s was for the bodywork of the land speed record car, Thunderbolt. Also used for the bodywork of Bluebird K7 used for the Coniston speed record attempt by Donald Campbell.

The well known Laurent Giles designed 46ft sailboat Beyond was built of riveted sheets of Birmabright and circumnavigated in the early 1950s by Tom and Ann Worth. The hull proved corrosion resistant but required re-riveting later due to crystallisation of the rivet heads, and lasted well until being sunk in the Caribbean as an artificial diving reef in the 1980s.

Birmetals (part of the Birmid Qualcast Group) closed its factory in 1980 after losing money in 1977-1979, followed by a protracted strike over wages by key staff which prevented production.

See also 
 Magnalium

References 

Aluminium–magnesium alloys
Aluminium alloys
Aerospace materials
Land Rover vehicles
NSIS. NSIS may refer to:

Technology
 National Sheep Identification System, the implementation in Ireland for the identification and registration of ovine and caprine animals
 Network Store Interface Service, a Microsoft Windows service
 Next Steps in Signaling, a former Internet Engineering Task Force working group
 Nullsoft Scriptable Install System, a script-driven Windows installation system
Nova Scotian Institute of Science, a membership organization promoting science in Nova Scotia

Other uses
 National Strategy for Information Sharing, part of Nationwide Suspicious Activity Reporting Initiative
 National Security Intelligence Section, of Ireland's Directorate of Military Intelligence
 Nova Scotian Institute of Science Nova Scotian Institute of Science
FLEX (operating system). FLEX is a discontinued single-tasking operating system developed by Technical Systems Consultants (TSC) of West Lafayette, Indiana, for the Motorola 6800 in 1976.

Overview
The original version was distributed on 8-inch floppy disks; the (smaller) version for 5.25-inch floppies is called mini-Flex. It was also later ported to the Motorola 6809; that version is called Flex09. All versions are text-based and intended for use on display devices ranging from printing terminals like the Teletype Model 33 ASR to smart terminals. While no graphic displays are supported by TSC software, some hardware supports elementary graphics and pointing devices.

FLEX is a disk-based operating system, using 256-byte sectors on soft-sectored floppies; the disk structure uses linkage bytes in each sector to indicate the next sector in a file or free list. The directory structure is  simplified as a result. TSC (and others) provide several programming languages including BASIC in two flavors (standard and extended) and a tokenizing version of extended BASIC called Pre-compiled BASIC, FORTH, C, FORTRAN, and PASCAL.

TSC also wrote a version of FLEX, Smoke Signal DOS, for the California hardware manufacturer Smoke Signal Broadcasting; this version uses forward and reverse linkage bytes in each sector which increase disk reliability at the expense of compatibility and speed.

Later, TSC introduced the multitasking, multi-user, Unix-like UniFLEX operating system, which requires DMA disk controllers, 8" disk, and sold in small numbers. Several of the TSC computer languages were ported to UniFLEX.

During the early 1980s, FLEX was offered by Compusense Ltd as an operating system for the 6809-based Dragon 64 home computer.

Commands
The following commands are supported by different versions of the FLEX operating system.

 APPEND
 ASN
 BACKUP
 BUILD
 CAT
 COPY
 COPYNEW
 C4MAT
 CLEAN
 DATE
 DELETE
 ECHO
 EXEC
 FIX
 GET
 I
 JUMP
 LINK
 LIST
 MEMTEST1
 MON
 N
 NEWDISK
 O
 P
 P.COR
 PO
 PRINT
 PROT
 PSP
 Q
 QCHECK
 READPROM
 RENAME
 RM
 S
 SAVE
 SAVE.LOW
 SBOX
 SP
 STARTUP
 TOUCH
 TTYSET
 UCAL
 USEMF
 VER
 VERIFY
 VERSION
 WRITPROM
 XOUT
 Y

See also
Microsoft BASIC-68 for FLEX
Microsoft BASIC-69 for FLEX

References

External links
 FLEX User Group
 FLEX User Group
 SWTPC 6800 FLEX 2 and 6809 FLEX 9 / UniFLEX / OS9 Level 1 emulator
 Windows-based 6809 Emulator + Flex09 and 6809 applications
 AmigaDOS-based 6809 Emulator + Flex09 and 6809 applications
 The Missing 6809 UniFLEX Archive
 DragonWiki
 SWTPC documentation collection 
 FLEX Software Archive

Discontinued operating systems
Disk operating systems
TRS-80 Color Computer
1976 software
SCL. SCL may refer to:

Computing 
 System Control Language, of the ICL VME operating system
 SC++L, the C++ standard library
 Software Collections in the CentOS Linux distribution
 System Command Language of the NOS/VE CDC Cyber operating system
 Structured Control Language, for programming PLCs

Language 
 Shina language, spoken by the Shina people in Gilgit-Baltistan, Pakistan

Organizations 
 SCL Group, a British data analysis and communication company
 Seattle City Light, public utility in Seattle, Washington, United States
 Southeastern Composers League
 Stanford Center on Longevity (SCL) Stanford University; see Stanford University centers and institutes
 National Senior Classical League
Society of Chief Librarians, former name of Libraries Connected, British public library organisation
 Society of Construction Law
 IATA airport code for Arturo Merino Benítez International Airport (Santiago International Airport)

Science and technology 
 Sculptor (constellation), astronomical abbreviation
 Semi-Conductor Laboratory of the Department of Space of India
 Serial clock, a signal in I²C electronic messaging bus
 Short circuit level
 Skin conductance level, in medicine
 Sleep Convention Logic, a typo of asynchronous logic
 Structural composite lumber, an engineered wood
 Substation Configuration Language, for electrical substations

Other 
 Arturo Merino Benítez International Airport, Santiago, Chile by IATA airport code
 Seaboard Coast Line Railroad, by reporting mark
 Security characteristic line, plotting performance of a security
 Sha Tin to Central Link of the Hong Kong MTR transit system
 Studies in Canadian Literature, a literary journal

See also 
 Symptom Checklist 90 (SCL-90-R), psychometric instrument