omniomni/omni-engineering huggingface dataset:
Martin Walt. Martin Walt (1926-2021) was a professor of electrical engineering at Stanford University. He specialized in magnetospheric physics. He was also the father of Stephen Walt, a professor at Harvard University's John F. Kennedy School of Government.

Education
He received his B.S. (Physics) from California Institute of Technology (1950),
his M.S. (Physics) from  University of Wisconsin–Madison (1951) and 
his Ph.D. (Physics), University of Wisconsin–Madison (1953).
His graduate education was in experimental nuclear physics.

Career
He worked for 1953–1956 at Los Alamos Scientific Laboratory.
From 1956 to 1992 he worked for the Research laboratory of the Lockheed Missiles and Space Company.
In 1993 he began teaching at Stanford University.

Honors and awards
He received the Wisconsin Alumni Research Foundation Fellowship in 1951 and Atomic Energy Commission Fellowship for 1952–1953.
He was a Fellow of the American Physical Society and the American Geophysical Union.

References

External links
Martin Walt (Official)
Publications
PIXIE
POLAR
SEPS

Stanford University faculty
American electrical engineers
21st-century American physicists
University of Wisconsin–Madison alumni
California Institute of Technology alumni
Fellows of the American Physical Society
Fellows of the American Geophysical Union
Lockheed Missiles and Space Company people
Chemical property. A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any attribute that can be established only by changing a substance's chemical identity. Simply speaking, chemical properties cannot be determined just by viewing or touching the substance; the substance's internal structure must be affected greatly for its chemical properties to be investigated. When a substance goes under a chemical reaction, the properties will change drastically, resulting in chemical change. However, a catalytic property would also be a chemical property.

Chemical properties can be contrasted with physical properties, which can be discerned without changing the substance's structure. However, for many properties within the scope of physical chemistry, and other disciplines at the boundary between chemistry and physics, the distinction may be a matter of researcher's perspective. Material properties, both physical and chemical, can be viewed as supervenient; i.e., secondary to the underlying reality. Several layers of superveniency are possible.

Chemical properties can be used for building chemical classifications. They can also be useful to identify an unknown substance or to separate or purify it from other substances. Materials science will normally consider the chemical properties of a substance to guide its applications.

Examples 
 Heat of combustion
 Enthalpy of formation
 Toxicity
 Chemical stability in a given environment
 Flammability (the ability to burn)
 Preferred oxidation state(s)
 Ability to corrode
 Combustibility
 Acidity and basicity
 creation of a new substance(s)
The ability to melt

See also

 Chemical structure
 Material properties
 Biological activity
 Quantitative structure–activity relationship (QSAR)
 Lipinski's Rule of Five, describing molecular properties of drugs

References
BESM. BESM (БЭСМ) is the series of Soviet mainframe computers built in 1950–60s. The name is an acronym for "Bolshaya (or Bystrodeystvuyushchaya)  Elektronno-schotnaya Mashina" ("Большая электронно-счётная машина" or "Быстродействующая электронно-счётная машина"), meaning "Big Electronic Computing Machine" or "High-Speed Electronic Computing Machine".  It was designed at the Institute of Precision Mechanics and Computer Engineering

Models
The BESM series included six models.

BESM-1
BESM-1, originally referred to as simply the BESM or BESM AN ("BESM Akademii Nauk", BESM of the Academy of Sciences), was completed in 1952. Only one BESM-1 machine was built. The machine used approximately 5,000 vacuum tubes. At the time of completion, it was the fastest computer in Europe. The floating-point numbers were represented as 39-bit words: 32 bits for the mantissa, one bit for sign, and 1 + 5 bits for the exponent. It was capable of representing numbers in the range 10−9 – 1010. BESM-1 had 1024 words of read–write memory using ferrite cores, and 1024 words of read-only memory based on semiconducting diodes. It also had external storage: four magnetic tape units of 30,000 words each, and fast magnetic drum storage with a capacity of 5120 words and an access rate of 800 words/second. The computer was capable of performing 8–10 K Flops. The energy consumption was approximately 30 kW, not accounting for the cooling systems.

BESM-2
BESM-2 also used vacuum tubes.

BESM-3M and BESM-4
BESM-3M and BESM-4 were built using transistors. Their architecture was similar to that of the M-20 and M-220 series. The word size was 45 bits. Thirty BESM-4 machines were built. BESM-4 was used to create the first ever computer animation. The prototypes of both models were made in 1962–63, and the beginning of the series release was in 1964.

EPSILON (a macro language with high-level features including strings and lists, developed by Andrey Ershov at Novosibirsk in 1967) was used to implement ALGOL 68 on the M-220.

BESM-6

The BESM-6 was the best-known and most influential model of the series. The design was completed in 1965. Production started in 1968 and continued for the following 19 years.

See also
 Sergei Alekseyevich Lebedev
 Lev Korolyov
 List of Soviet computer systems
 History of computing hardware
 History of computing in the Soviet Union
 List of vacuum tube computers

References

Further reading
 
  A museum curator suggests Russia's BESM supercomputer may have been superior to the USA's supercomputers during the early stages of the Cold War.
 

Mainframe computers
Supercomputers
Vacuum tube computers
Soviet inventions
Transistorized computers
Soviet computer systems
Bristol Phoenix. The Phoenix was an experimental version of the Bristol Aeroplane Company's Pegasus engine, adapted to run on the Diesel cycle. Only a few were built between 1928 and 1932, although samples fitted to a Westland Wapiti held the altitude record for diesel-powered aircraft at 27,453 ft (8,368 m) from 11 May 1934 until World War II. The primary advantage of the Phoenix was better fuel efficiency at cruise, by up to 35%.

Variants
 Phoenix I: Diesel version of the Pegasus IF, 380 hp.
 Phoenix IIM: Medium-supercharged diesel version of Pegasus IM, 470 hp.

Applications
Westland Wapiti

Specifications (Phoenix I)

See also

References

Notes

Bibliography

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

External links
Bristol Phoenix and Westland Wapiti - Flight, May 1934

Aircraft air-cooled radial piston engines
Aircraft radial diesel engines
Phoenix
1920s aircraft piston engines
Token bus network. In computer networking, a token bus network is a network implementing a token-passing protocol over a virtual ring on a coaxial cable.

Network
A token is passed around the network nodes and only the node possessing the token may transmit. If a node doesn't have anything to send, the token is passed on to the next node on the virtual ring. Each node must know the address of its neighbour in the ring, so a special protocol is needed to notify the other nodes of connections to, and disconnections from, the ring.

Ethernet's access protocol could not absolutely guarantee a maximum time any station would have to wait to access the network, so was thought to be unsuitable for manufacturing automation applications. The Token bus protocol was created to combine the benefits of a physical bus network with the deterministic access protocol of a Token Ring network.

IEEE 802.4
Token Bus was standardized by IEEE standard 802.4.  It was mainly used for industrial applications. Token Bus was used by General Motors for their Manufacturing Automation Protocol (MAP) standardization effort. This differs from Token Ring networks in that the endpoints of the bus do not meet to form a physical ring.

In order to guarantee the packet delay and transmission in the Token Bus protocol, a modified Token Bus was proposed in manufacturing automation systems and flexible manufacturing system (FMS). To optimize deterministic access required by real-time IoT communication in a distributed manufacturing plant or IIoT, token bus method can also be implemented according to IEEE 802.15.4.  

A means for carrying Internet Protocol over IEEE 802 networks, including token bus networks, was developed.

The IEEE 802.4 Working Group has disbanded and the standard has been withdrawn by the IEEE.

See also 
 ARCNET
 Network topology

References

Local area networks
IEEE 802
Link protocols
Vertical blank interrupt. A vertical blank interrupt (or VBI) is a hardware feature found in some legacy computer systems that generate a video signal. Cathode-ray tube based video display circuits generate vertical blanking and vertical sync pulses when the display picture has completed and the raster is being returned to the start of the display. With VBI, the vertical blank pulse is also used to generate an interrupt request for the computer's microprocessor.

The interrupt service routine can then modify data in the video display memory while it is not being read to avoid screen tearing effects. This was particularly useful in simple home computers and video game consoles that relied upon a central microprocessor to generate text or graphic displays. More advanced home computers featuring hardware sprites often supported the more flexible horizontal blank interrupt instead in order to allow them to be multiplexed.

As the VBI will be generated at the start of every displayed frame (50 Hz for PAL, 60 Hz for NTSC), it is a useful timebase in systems lacking other timing sources. VBIs are used in some home computers to perform regular functions like scanning the keyboard and joystick ports. It can also be used to implement a basic form of multitasking as well as a buffered graphics screen via page flipping, if hardware permits.

Modern protected mode operating systems generally do not support VBIs as access to hardware interrupts for unprivileged user programs could compromise the system stability. Instead, various APIs like DirectX provide efficient and safe ways to present graphics free of tear and flicker.

For computers that support VBIs see the page about raster interrupts.

See also
Horizontal blank interrupt

References

Video game development
ABC (programming language). ABC is an imperative general-purpose programming language and integrated development environment (IDE) developed at Centrum Wiskunde & Informatica (CWI), in  Amsterdam, Netherlands by Leo Geurts, Lambert Meertens, and Steven Pemberton. It is interactive, structured, high-level, and intended to be used instead of BASIC, Pascal, or AWK. It is intended for teaching or prototyping, but not as a systems-programming language.

ABC had a major influence on the design of the language Python, developed by Guido van Rossum, who formerly worked for several years on the ABC system in the mid-1980s.

Features
Its designers claim that ABC programs are typically around a quarter the size of the equivalent Pascal or C programs, and more readable. Key features include:

Only five basic data types
No required variable declarations
Explicit support for top-down programming
Statement nesting is indicated by indentation, via the off-side rule
Infinite precision arithmetic, unlimited-sized lists and strings, and other features supporting orthogonality and ease of use by novices
 Polymorphic commands and functions
 Interactive environment with command completion, persistent workspaces, and no separate file handling

ABC was originally a monolithic implementation, leading to an inability to adapt to new requirements, such as creating a graphical user interface (GUI). ABC could not directly access the underlying file system and operating system.

The full ABC system includes a programming environment with a structure editor (syntax-directed editor), suggestions, static variables (persistent), and multiple workspaces, and is available as an interpreter–compiler. , the latest version is 1.05.02, and it is ported to Unix, DOS, Atari, and Apple MacOS.

Example
An example function to collect the set of all words in a document:

 HOW TO RETURN words document:
    PUT {} IN collection
    FOR line IN document:
       FOR word IN split line:
          IF word not.in collection:
             INSERT word IN collection
    RETURN collection

Implementations 
ABC has been through multiple iterations, with the current version being the 4th major release. Implementations exist for Unix-like systems, MS-DOS/Windows, Macintosh, and other platforms. The source code was made available via Usenet in the late 1980s/early 1990s.

Further reading 
More details on ABC can be found in the book "The ABC Programmer's Handbook" by Leo Geurts, Lambert Meertens and Steven Pemberton (ISBN 0-13-000027-2). A newsletter and mailing list were available from CWI.

References

External links
ABC Programmer's Handbook

Computer science in the Netherlands
Dutch inventions
Educational programming languages
Information technology in the Netherlands
Persistent programming languages
Procedural programming languages
Programming languages created in the 1980s
DTP. DTP may refer to:

Computing
 Data Transfer Project, an open-source initiative on data portability
 Dependently typed programming
 Desktop publishing, the creation of documents using page layout skills on a personal computer	 
 Digital Teaching Platform, educational products
 Distributed transaction processing, the X/Open model of coordinating transactions between multiple participants
 Dynamic Trunking Protocol, a networking protocol from Cisco
 Parasoft DTP, development testing platform

Medicine
 Developmental Therapeutics Program, of the National Cancer Institute
 Diphtheria toxin
 Distal tingling on percussion, another term for Tinel's sign
 Drug therapy problems, a categorization of drug problems in pharmaceutical care
 DTP vaccine, a triple vaccine used to inoculate against diphtheria, tetanus and pertussis, also referred as DPT

Music
 Devin Townsend Project, a rock and metal group
 Disturbing tha Peace, a record label
 DTP (Sadus album)

Organizations
 Democrat Turkey Party (Democrat Türkiye Partisi), a minor party in the late 1990s
 Demokratik Toplum Partisi (Democratic Society Party), a former pro-Kurdish political party in Turkey
 Dick Johnson Racing, formerly DJR Team Penske, Australia's oldest motor racing team competing in the Supercars Championship
 Doctoral Training Partnerships, British centres for managing PhD studies
 dTP Entertainment, a German video game producer

Other
 Dubai Techno Park, a technology park in Dubai, UAE
 Dusun language (ISO 639-3 code: dtp), an Austronesian language primarily spoken in Malaysia
 Dynamic tidal power, a proposed technology to generate energy from the oceans
Straightedge. A straightedge or straight edge is a tool used for drawing straight lines, or checking their straightness. If it has equally spaced markings along its length, it is usually called a ruler.

Straightedges are used in the automotive service and machining industry to check the flatness of machined mating surfaces. They are also used in the decorating industry for cutting and hanging wallpaper.

True straightness can in some cases be checked by using a laser line level as an optical straightedge: it can illuminate an accurately straight line on a flat surface such as the edge of a plank or shelf.

A pair of straightedges called winding sticks are used in woodworking to make warping easier to perceive in pieces of wood.

Three straight edges can be used to test and calibrate themselves to a certain extent, however this procedure does not control twist.  For accurate calibration of a straight edge, a surface plate must be used.

Compass-and-straightedge construction

An idealized straightedge is used in compass-and-straightedge constructions in plane geometry.

It may be used:
 Given two points, to draw the line connecting them
 Given a point and a circle, to draw either tangent
 Given two circles, to draw any of their common tangents
 Or any of the other numerous geometric constructions

The idealized straightedge is:
 Infinitely long
 Infinitesimally thin (i.e. point width)
 Always assumed to be without graduations or marks, or the ability to mark
 Able to be aligned to two points with infinite precision to draw a line through them

It may not be marked or used together with the compass so as to transfer the length of one segment to another.

It is possible to do all compass and straightedge constructions without the straightedge. That is, it is possible, using only a compass, to find the intersection of two lines given two points on each, and to find the tangent points to circles. It is not, however, possible to do all constructions using only a straightedge. It is possible to do them with straightedge alone given a circle and its center.

See also
 Chalk line
 Geometrography

References

External links

 Making Accurate Straight-Edges from Scratch

Mathematical tools
Metalworking measuring instruments
Stonemasonry tools
Technical drawing tools
Woodworking measuring instruments
Random optimization. Random optimization (RO) is a family of numerical optimization methods that do not require the gradient of the optimization problem and RO can hence be used on functions that are not continuous or differentiable. Such optimization methods are also known as direct-search, derivative-free, or black-box methods.

The name random optimization is attributed to Matyas  who made an early presentation of RO along with basic mathematical analysis. RO works by iteratively moving to better positions in the search-space which are sampled using e.g. a normal distribution surrounding the current position.

Algorithm 

Let  be the fitness or cost function which must be minimized. Let  designate a position or candidate solution in the search-space. The basic RO algorithm can then be described as:

 Initialize x with a random position in the search-space.
 Until a termination criterion is met (e.g. number of iterations performed, or adequate fitness reached), repeat the following:
 Sample a new position y by adding a normally distributed random vector to the current position x
 If (f(y) < f(x)) then move to the new position by setting x = y
 Now x holds the best-found position.

This algorithm corresponds to a (1+1) evolution strategy with constant step-size.

Convergence and variants 
Matyas showed the basic form of RO converges to the optimum of a simple unimodal function by using a limit-proof which shows convergence to the optimum is certain to occur if a potentially infinite number of iterations are performed. However, this proof is not useful in practice because a finite number of iterations can only be executed. In fact, such a theoretical limit-proof will also show that purely random sampling of the search-space will inevitably yield a sample arbitrarily close to the optimum.

Mathematical analyses are also conducted by Baba  and Solis and Wets  to establish that convergence to a region surrounding the optimum is inevitable under some mild conditions for RO variants using other probability distributions for the sampling. An estimate on the number of iterations required to approach the optimum is derived by Dorea. These analyses are criticized through empirical experiments by Sarma  who used the optimizer variants of Baba and Dorea on two real-world problems, showing the optimum to be approached very slowly and moreover that the methods were actually unable to locate a solution of adequate fitness, unless the process was started sufficiently close to the optimum to begin with.

See also 
 Random search is a closely related family of optimization methods which sample from a hypersphere instead of a normal distribution.
 Luus–Jaakola is a closely related optimization method using a uniform distribution in its sampling and a simple formula for exponentially decreasing the sampling range.
 Pattern search takes steps along the axes of the search-space using exponentially decreasing step sizes.
 Stochastic optimization

References 

Optimization algorithms and methods
Preliminary Design of an Experimental World-Circling Spaceship. The "Preliminary Design of an Experimental World-Circling Spaceship" was a 1946 proposal by Project RAND for a United States satellite program. Robert M. Salter, James E. Lipp and one other person at RAND served as the editors of the report.

The Preliminary Design of an Experimental World-Circling Spaceship states, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century. The achievement of a satellite craft would produce repercussions comparable to the explosion of the atomic bomb.."

References

External links
Preliminary Design of an Experimental World-Circling Spaceship

Spaceflight
Hypothetical spacecraft
RAND Corporation
Plastic in art. Within the 20th century, there came the use of plastics in art. In the latter half of the century, plastic technology advanced so that it was feasible for artists to start using plastic and acrylics as an artwork medium.

Using found plastic 

Art made of commodity materials sometimes uses found objects made of plastic. Plastic containers are useful in papier-mâché for building frames.

Environmental artists are using salvaged beach plastic to create art as a means of bringing awareness of plastic pollution in Earth's oceans. Examples include: Judith Selby Lang and Richard Lang, members of Women Eco Artists Dialog, and the photography of Chris Jordan.

Use of liquid acrylics
Liquid acrylics can be used to create two- and three-dimensional plastic images and objects. Artist, Tyler Turkle, pours multiple thin layers of pigmented liquid acrylic to form sheets of plastic that result in paintings and sculptures. After adequate drying time between applications, these solid plastic sheets can be readily peeled off most surfaces and re-adhered to others.

Gallery

See also
Acrylic paint
New materials in 20th-century art
Plastic arts

References

Visual arts materials