omniomni/omni-engineering huggingface dataset:
Armstrong Siddeley Leopard. The Armstrong Siddeley Leopard was a British 14-cylinder twin-row air-cooled radial aero engine developed in 1927 by Armstrong Siddeley. It was the most powerful radial engine in the world when introduced.

Variants
Leopard I
700 hp, medium supercharged. Direct drive propeller.
Leopard II
700 hp, geared epicyclic drive.
Leopard III
800 hp, two-valve cylinder head, direct drive.
Leopard IIIA
800 hp, geared epicyclic drive.

Applications
Blackburn Iris
Junkers Ju 52
Hawker Dantorp
Hawker Horsley

Specifications (Leopard I)

See also

References

Notes

Bibliography

 Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. .
 Mason, Francis K. Hawker Aircraft since 1920 (third ed.). London: Putnam, 1991. .
 Smith, Herschel. Aircraft Piston Engines. New York, New York: McGraw-Hill, 1981. .

1920s aircraft piston engines
Aircraft air-cooled radial piston engines
Leopard
Armstrong Siddeley Panther. The Armstrong Siddeley Panther was a 27-litre 14-cylinder twin-row air-cooled radial aero engine developed by Armstrong Siddeley. It was originally named the Jaguar Major.

Variants 

AS Panther IIIA500 hp (370 kW)
AS Panther VII638 hp (478 kW) at 2,400 rpm with 0.5 psi (3.5 kPa) boost

Applications 
 Armstrong Whitworth Atlas (Mk II)
 Armstrong Whitworth A.W.XIV Starling MkII
 Armstrong Whitworth A.W.16
 Armstrong Whitworth A.W.35 Scimitar
 Fairey Gordon
 Fokker C.V
 Hawker Hoopoe
 Marinens Flyvebaatfabrikk M.F.11
 Supermarine Air Yacht
 Svenska Aero Jaktfalken (SA-14E)
 Westland Wapiti V (first prototype)

Specifications (Panther VII)

See also

References

Notes

Bibliography 

 Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. .

1920s aircraft piston engines
Aircraft air-cooled radial piston engines
Panther
Armstrong Siddeley Lynx. The Armstrong Siddeley Lynx is a British seven-cylinder aero engine developed by Armstrong Siddeley.  It was developed as a single row version of the two-row Armstrong Siddeley Jaguar. Testing began in 1920 and 6,000 had been produced by 1939. In Italy Alfa Romeo built a  licensed version of this engine named the Alfa Romeo Lynx.

Variants
Lynx I
1920, .
Lynx II
1920, .
Lynx III
1924, .
Lynx IV
1929, .
Lynx IVA
1930, .
Lynx IVB
1930, .
Lynx IVC
1929, .
Lynx IV(G)
1929, Geared propeller drive. 
Lynx IV(MOD)
1929, , reconditioned and modified Lynx IV.
Lynx IV(S)
1928, , fully supercharged.
Lynx V (Lynx Major)

1930, increased bore and stroke, name changed from Lynx V to Lynx Major then Cheetah. Effectively half a Panther
Piaggio P.II Licence production in Italy by Piaggio.

Applications

Airspeed Courier
Airspeed Envoy
Albatros L 68
Avro 504
Avro 618 Ten
Avro Avocet
Avro 641 Commodore
Avro 626
Avro 642/4m Eighteen
Avro Sea Tutor
Avro Tutor
BAT Bantam
Blackburn Lincock
Boulton Paul Bittern
Canadian Vickers Vanessa
Canadian Vickers Varuna
Canadian Vickers Vedette
Cierva C.8
de Havilland Hawk Moth

Fairchild FC-2
Fokker C.VII
Fokker F.VIIA
Gloster Grouse
Messerschmitt M 18
Morane-Saulnier MS.230
Nieuport-Delage NiD 39
Larynx
Parnall Parasol
Raab-Katzenstein RK-26
Wackett Warrigal
Saro Cloud
Saro Cutty Sark
Supermarine Seamew
Vickers Vireo
VL Tuisku
Westland Wagtail

Alfa Romeo Lynx
Breda Ba.19
Breda Ba.25
IMAM Ro.10

Survivors
Avro Tutor, K3215, powered by a Lynx IV, flies regularly at the Shuttleworth Collection and can be viewed in the museum at other times.

Specifications (Lynx IV)

See also

References

Notes

Bibliography

 Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. .

1920s aircraft piston engines
Aircraft air-cooled radial piston engines
Lynx
Bristol Siddeley Nimbus. The Bristol Siddeley Nimbus, later known as the Rolls-Royce Nimbus, was a British turboshaft engine developed under license by Blackburn Aircraft Ltd. from the Turbomeca Turmo in the late 1950s. It was used on the Westland Scout and Westland Wasp helicopters.

Design and development
The Nimbus is a turboshaft engine comprising a gas generator section, which consists of a three-stage compressor, (two axial stages and one centrifugal stage), driven by a two-stage turbine in conjunction with an annular combustion chamber, and a power output section consisting of a single-stage free turbine driving an output shaft via a two-stage reduction gearbox.

In the Scout and Wasp the main rotor drive is taken from the front of the gearbox and is transmitted beneath the gas generator via a flexible coupling, while the drive for the tail rotor is taken from the rear of the gearbox.

The fuel system is designed to control and govern the engine under all operating conditions and to provide safeguards against malfunctions, the pilot selecting rotor speed and the governing element automatically maintaining the rotor speed within close limits under varying conditions of load.

The lubrication system is self-contained, the oil tank being integral with the air intake casing.

Engine and helicopter accessories are mounted on a gearbox located on the air intake casing.

Variants
The Nimbus engines were produced in two main variants, the Mark 103/503 and the Mark 105/502. The Mark 103/503 is generally similar to the Mark 105/502 except that the former has a double-caliper disc brake incorporated in the output drive shaft to provide adequate braking of the helicopter's rotor in the high winds encountered over the deck of a fast moving ship, whereas the 105/502 has a single caliper unit.
Blackburn-Turbomeca A.129:
BnN.1 Nimbus:
BnN.2 Nimbus:
BnN.2/1 Nimbus:
BnN.2/2 Nimbus:
Nimbus 500:
Nimbus 502: (Mk.105)
Nimbus 503: (Mk.103)
Nimbus Mk.103:
Nimbus Mk.105:

Applications

Westland Scout
Westland Wasp
Saunders-Roe SR.N2, Hovercraft

Specifications (Nimbus)

See also

References

Notes

Bibliography

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

1950s turboshaft engines
Nimbus
Armstrong Siddeley Mongoose. The Armstrong Siddeley Mongoose is a British five-cylinder radial aero engine produced by Armstrong Siddeley. Developed in the mid-1920s it was used in the Hawker Tomtit trainer and Parnall Peto seaplane amongst others. With a displacement of 540 cubic inches (9 litres) the Mongoose had a maximum power output of 155 horsepower (115 kilowatts).

A Mongoose engine powers the sole remaining airworthy Hawker Tomtit, based at Old Warden.

Design and development
The Mongoose is a five-cylinder, single-row, air-cooled radial piston engine. The engine features twin forward-mounted ignition magnetos and enclosed valve rockers, the cylinders being the same as those used for the earlier Jaguar engine. An unusual feature of the Mongoose is the vertical position of the lower cylinder, a design thought likely to promote oil fouling of the spark plugs.

Built in several variants, power output ranged between 135 and 155 hp (100-115 kW).

Variants
Mongoose I 
1926, 135 hp.
Mongoose II
1930, 155 hp.
Mongoose III 
1929.
Mongoose IIIA
1929, civil use.
Mongoose IIIC 
1929, Military use based on IIIA.

Applications

Note:
ANBO III (Second batch, 1931)
Avro 504N
Avro 504R
Avro Tutor
Avro Type 621 Trainer
Handley Page Hamlet
Handley Page Gugnunc 
Hawker Tomtit
Parnall Peto
Fokker S.IV

Survivors
An Armstrong Siddeley Mongoose IIIC powers the sole remaining airworthy Hawker Tomtit, K1786/G-AFTA, owned and operated by the Shuttleworth Collection this aircraft flies regularly throughout the summer months.

Specifications (Mongoose I)

See also

References

Notes

Bibliography

 Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. 
 Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. .

External links

Armstrong Siddeley Mongoose - Flight, July 1929

Aircraft air-cooled radial piston engines
Mongoose
1920s aircraft piston engines
Space Telescope Science Data Analysis System. The Space Telescope Science Data Analysis System (STSDAS) is an IRAF-based suite of astronomical software for reducing and analyzing astronomical data.  It contains general purpose tools and packages for processing data from the Hubble Space Telescope. STSDAS is produced by Space Telescope Science Institute (STScI).  The STSDAS software is generally in the public domain, however some routines were taken from the Numerical Recipes and other books and cannot freely distributed.

In 2018, STScI stopped support of IRAF and STSDAS and suggested migrating to Astropy. For the support of the Gemini IRAF legacy pipeline, selected tasks of STSDAS are still maintained by NOIRLab in the st4gem package.

See also 

Space flight simulation game
List of space flight simulation games
Planetarium software
List of observatory software

References

External links
STSDAS Home Page
Git repository for the Open Source portion of STSDAS
Git repository for ST4GEM

Free astronomy software
Hubble Space Telescope
Direct coupling. In electronics, direct coupling or DC coupling (also called conductive coupling and galvanic coupling) is the transfer of electrical energy by means of physical contact via a conductive medium, in contrast to inductive coupling and capacitive coupling. It is a way of interconnecting two circuits such that, in addition to transferring the AC signal (or information), the first circuit also provides DC bias to the second.  Thus, DC blocking capacitors are not used or needed to interconnect the circuits. Conductive coupling passes the full spectrum of frequencies including direct current.

Such coupling may be achieved by a wire, resistor, or common terminal, such as a binding post or metallic bonding.

DC bias
The provision of DC bias only occurs in a group of circuits that forms a single unit, such as an op-amp. Here the internal units or portions of the op-amp (like the input stage, voltage gain stage, and output stage) will be direct coupled and will also be used to set up the bias conditions inside the op-amp (the input stage will also supply the input bias to the voltage gain stage, for example). However, when two op-amps are directly coupled the first op-amp will supply any bias to the next - any DC at its output will form the input for the next. The resulting output of the second op-amp now represents an offset error if it is not the intended one.

Uses
This technique is used by default in circuits like IC op-amps, since large coupling capacitors cannot be fabricated on-chip. That said, some discrete circuits (such as power amplifiers) also employ direct coupling to cut cost and improve low frequency performance.

Offset error
One advantage or disadvantage (depending on application) of direct coupling is that any DC at the input appears as a valid signal to the system, and so it will be transferred from the input to the output (or between two directly coupled circuits). If this is not a desired result, then the term used for the output signal is output offset error, and the corresponding input signal is known as input offset error.

Error correction
Temperature drift and device mismatches are the major causes of offset errors, and circuits employing direct coupling often integrate offset nulling mechanisms. Some circuits (like power amplifiers) even use coupling capacitors—except that these are present only at the input (and/or output) of the whole system but not between the individual circuit units inside the system.

Advantages
The advantage of direct coupling is very good low frequency response, often from DC to the highest operating frequency that the system will allow. All applications that require monitoring of slowly changing signals (such as those from thermistors, thermocouples, strain gages, etc.) must have a very good DC amplification with minimum offset errors and hence they must be directly coupled throughout, and have offset correction or trimming incorporated into them.

See also
 Direct-coupled amplifier
 Electromagnetic compatibility
 Electromagnetic interference
 Galvanic isolation
 Ohmic contact

References

External links 
 Common Impedance Coupling

Electromagnetic compatibility
Electronic amplifiers
OpenBIOS. OpenBIOS is a project aiming to provide free and open source implementations of Open Firmware. It is also the name of such an implementation.

Most of the implementations provided by OpenBIOS rely on additional lower-level firmware for hardware initialization, such as coreboot or Das U-Boot.

Provided implementations

Open Firmware 

Open Firmware implements the IEEE 1275-1994 standard. Open Firmware was released by the company Firmworks. The principal architect of Open Firmware, Mitch Bradley, is chairman of the Open Firmware Working Group and president and founder of Firmworks. The OLPC XO-1 laptop uses the Open Firmware implementation.
It supports the x86, PowerPC, and ARM architectures, and is released under the terms of a BSD style license.

SmartFirmware 

SmartFirmware includes a C to FCode compiler. It is made by CodeGen, Inc.
It is written in ANSI C and supports the x86, PowerPC, SPARC, ARM, MIPS architectures.

OpenBOOT 

OpenBOOT was released by Sun Microsystems.  It supports the sun4v architecture.

OpenBIOS 
OpenBIOS is portable and licensed under the GPL. It is produced by the OpenBIOS project.

SLOF 

Slimline Open Firmware is produced by IBM, and is released under a BSD style license.
It supports the PowerPC architecture.

See also 

 Coreboot

References

External links
 
 SmartFirmware source code

Custom firmware
Free BIOS implementations
Firmware
Software related to embedded Linux
Diglyme. Diglyme, or bis(2-methoxyethyl) ether, is an organic compound with the chemical formula . It is a colorless liquid with a slight ether-like odor. It is a solvent with a high boiling point. It is the dimethyl ether of diethylene glycol. The name diglyme is a portmanteau of diglycol methyl ether. It is miscible with water as well as organic solvents.

It is prepared by a reaction of dimethyl ether and ethylene oxide over an acid catalyst.

Solvent

Because of its resistance to strong bases, diglyme is favored as a solvent for reactions of alkali metal reagents even at high temperatures. Rate enhancements in reactions involving organometallic reagents, such as Grignard reactions or metal hydride reductions, have been observed when using diglyme as a solvent.

Diglyme is also used as a solvent in hydroboration reactions with diborane.

It serves as a chelate for alkali metal cations, leaving anions more active.

Safety
The European Chemicals Agency lists diglyme as a substance of very high concern (SVHC) as a reproductive toxin.

At higher temperatures and in the presence of active metals diglyme is known to decompose, which can produce large amounts of gas and heat. This decomposition led to the T2 Laboratories reactor explosion in 2007.

References

Glycol ethers
Chelating agents
Hazardous air pollutants
Bapatla Engineering College. Bapatla Engineering College   (BEC) is a private engineering college, and is one of the seven educational institutions sponsored by the Bapatla Education Society. BEC was established in 1981. The founder president for this institute is Yarlagadda Krishna Murthy. It is located in Bapatla district. The college primarily offers courses pertaining to technology and science, including: information technology, machine learning and data science.

References

All India Council for Technical Education
Engineering colleges in Andhra Pradesh
1981 establishments in Andhra Pradesh
Universities and colleges established in 1981
Trimmer (construction). In light-frame construction, a  trimmer is a timber or metal beam (joist) used to create an opening around a stairwell, skylight, chimney, and the like.  Trimmers are installed parallel to the primary floor or ceiling joists and support headers, which run perpendicular to the primary joists.

It can also refer to a jack stud that supports a header above a window or door opening.

Traditionally, a stud which was less than full length was sometimes referred to as a cripple.

References 

Structural system
Logic Lane covered bridge. 

The Logic Lane covered bridge is a small covered bridge at the High Street end of Logic Lane, within University College, Oxford, England.

The bridge was designed by the Oxford architect Harry Wilkinson Moore (1850–1915) and was completed in 1904. It links the older Radcliffe Quad buildings with the newer Durham Buildings, built in 1903. Oxford City Council was against the scheme, since Logic Lane was officially a bridleway, but the court judged in favour of the College—so the bridge was built.

See also
Bridge of Sighs, another better-known covered bridge in Oxford at Hertford College.

References

External links
University College, Bridge, Oxford, Oxfordshire 1906 photograph by Henry Taunt from English Heritage

Covered bridge, Logic Lane
Bridges in Oxford
Covered bridges in England
Buildings and structures of the University of Oxford
Bridges completed in 1904
Signal tracer. A signal tracer is a piece of electronic test equipment used to troubleshoot radio and other electronic circuitry.

Usually a very simple device, it normally provides an amplifier, and a loudspeaker, often battery-powered and packaged into a small, hand-held test probe. An optional diode detector is usually also provided, allowing the detection of amplitude-modulated signals.

The technician injects a test signal into the device under test. Then, by using the signal tracer, the tech can follow the signal through the various circuits of the radio receiver. So long as the signal can be heard, the circuitry up to that point is (at least minimally) functional. If the signal disappears, however, a fault can be assumed to be present in the stage of the circuit just passed.

The diode detector is only sensitive to amplitude modulation but even circuits that are normally used for other modulation schemes (such as FM radios) can be tested by using an AM test signal for testing the radio frequency circuits, then switching to an FM test signal (and switching out the diode detector) for testing the audio circuits of the radio.

More sophisticated signal tracers may display digital levels using, for example, LEDs. For long pulse trains, a cyclic redundancy check may be calculated and displayed, giving the tech insight into the content of circuits that are switching rapidly.

References

Electronic test equipment
Minion (solver). Minion is a solver for constraint satisfaction problems. Unlike constraint programming toolkits, which expect users to write programs in a traditional programming language like C++, Java or Prolog, Minion takes a text file which specifies the problem, and solves using only this. This makes using Minion much simpler, at the cost of much less customization.

This limitation allows Minion to be many times faster than competing commercial solvers, for example Minion was found to be faster than the major commercial constraint solver, CPLEX (formerly ILOG CPLEX then IBM ILOG).

References

External links
 Github Repository

Constraint programming
PAL (programming language). PAL, the Pedagogic Algorithmic Language, is a programming language developed at the Massachusetts Institute of Technology in around 1967 to help teach programming language semantics and design. It is a "direct descendant" of ISWIM and owes much of its philosophy to Christopher Strachey.

The initial implementation of PAL, in Lisp, was written by Peter Landin and James H. Morris, Jr. and ran under CTSS. It was later redesigned by Martin Richards, Thomas J. Barkalow, Arthur Evans, Jr., Robert M. Graham, James Morris, and John Wozencraft. It was implemented by Richards and Barkalow in BCPL as an intermediate-code interpreter and ran on the IBM System/360; this was called PAL/360.

RPAL
RPAL, the Right-reference Pedagogic Algorithmic Language, is a functional subset of PAL with an implementation on SourceForge. It is used at the University of Florida to teach the construction of programming languages and functional programming.  Programs are strictly functional, with no sequence or assignment operations.

References

Programming languages created in 1967
Academic programming languages
Functional languages
Aluminium indium arsenide. Aluminium indium arsenide, also indium aluminium arsenide or AlInAs (AlxIn1−xAs), is a ternary III-V semiconductor compound with very nearly the same lattice constant as InGaAs, but a larger bandgap. It can be considered as an alloy between aluminium arsenide (AlAs) and indium arsenide (InAs). AlInAs refers generally to any composition of the alloy.

Structural and Electronic Properties 

The bandgap and lattice constant of AlInAs alloys are between those of pure AlAs (a = 0.566 nm, Eg = 2.16 eV) and InAs (a = 0.606 nm, Eg = 0.42 eV). At a composition of approximately x = 0.64, the band gap transitions between direct and indirect.

AlInAs shares the same zincblende crystal structure as AlAs and InAs.

Applications 
Aluminium indium arsenide is used e.g. as a buffer layer in metamorphic HEMT transistors, where it serves to adjust the lattice constant differences between the GaAs substrate and the GaInAs channel. It can be also used to form alternate layers with indium gallium arsenide, which act as quantum wells; these structures are used in, e.g., broadband quantum cascade lasers.

Safety and toxicity aspects 
The toxicology of AlInAs has not been fully investigated. The dust is an irritant to skin, eyes and lungs. The environment, health and safety aspects of aluminium indium arsenide sources (such as trimethylindium and arsine) and industrial hygiene monitoring studies of standard MOVPE sources have been reported recently in a review.

References 

III-V semiconductors
III-V compounds
Arsenides
Aluminium compounds
Indium compounds
Zincblende crystal structure
Collaborative Computational Project Number 4. The Collaborative Computational Project Number 4 in Protein Crystallography (CCP4) was set up in 1979 in the United Kingdom to support collaboration between researchers working in software development and assemble a comprehensive collection of software for structural biology. The CCP4 core team is located at the Research Complex at Harwell (RCaH) at Rutherford Appleton Laboratory (RAL) in Didcot, near Oxford, UK.

CCP4 was originally supported by the UK Science and Engineering Research Council (SERC), and is now supported by the Biotechnology and Biological Sciences Research Council (BBSRC). The project is coordinated at CCLRC Daresbury Laboratory. The results of this effort gave rise to the CCP4 program suite, which is now distributed to academic and commercial users worldwide.

Projects
CCP4i – CCP4 Graphical User Interface
CCP4MG – CCP4 Molecular Graphics Project
Coot – Graphical Model Building
HAPPy – automated experimental phasing
MrBUMP – automated Molecular Replacement
PISA – Protein Interfaces, Surfaces and Assemblies
MOSFLM GUI – building a modern interface to MOSFLM

See also 
 CCP4 (file format)

External links 
 
 CCP4 Documentation wiki — concentrates only on CCP4
 CCP4 Community wiki — general X-ray crystallography topics related to CCP4

References 

Crystallography
Medical Research Council (United Kingdom)
Science and technology in Oxfordshire
Vale of White Horse
MCPO. MCPO is a chemical compound that can be used to produce chemiluminescence. MCPO is mainly used for its chemiluminescent properties and is most commonly used in demonstrations of chemiluminescence as a safer alternative to TCPO. It is used as an alternative to TCPO due to its safer reaction product of methyl salicylate rather than the product of TCP, 2,4,6-trichlorophenol, a known carcinogen.

Synthesis
MCPO is synthesized by reacting methyl salicylate with oxalyl chloride in a solution of THF and pyridine:

Pyridine reacts with HCl produced forming the THF insoluble pyridine hydrochloride salt. Water is then added to the solution to dissolve the precipitated pyridine HCl and decrease the solubility of the MCPO in solution, causing it to precipitate. The MCPO precipitate is then filtered and washed with water to remove contaminants.

See also
TCPO

References

Chemiluminescence
Salicylate esters
Methyl esters
Oxalate esters
Salicylyl esters