omniomni/omni-engineering huggingface dataset:
Lamella (materials). A lamella (: lamellae) is a small plate or flake, from the Latin, and may also refer to collections of fine sheets of material held adjacent to one another in a gill-shaped structure, often with fluid in between though sometimes simply a set of "welded" plates. The term is used in biological contexts for thin membranes of plates of tissue. In the context of materials science, the microscopic structures in bone and nacre are called lamellae. Moreover, the term lamella is often used to describe crystal structure of some materials.

Uses of the term
In surface chemistry (especially mineralogy and materials science), lamellar structures are fine layers, alternating between different materials. They can be produced by chemical effects (as in eutectic solidification), biological means, or a deliberate process of lamination, such as pattern welding. Lamellae can also describe the layers of atoms in the crystal lattices of materials such as metals.

In surface anatomy, a lamella is a thin plate-like structure, often one amongst many lamellae very close to one another, with open space between.

In chemical engineering, the term is used for devices such as filters and heat exchangers.

In mycology, a lamella (or gill) is a papery hymenophore rib under the cap of some mushroom species, most often agarics.

The term has been used to describe the construction of lamellar armour, as well as the layered structures that can be described by a lamellar vector field.

In medical professions, especially orthopedic surgery, the term is used to refer to 3D printed titanium technology which is used to create implantable medical devices (in this case, orthopedic implants).

In context of water-treatment, lamellar filters may be referred to as plate filters or tube filters.

This term is used to describe a certain type of ichthyosis, a congenital skin condition. Lamellar Ichthyosis often presents with a "colloidal" membrane at birth.  It is characterized by generalized dark scaling.

The term lamella(e) is used in the flooring industry to describe the finished top-layer of an engineered wooden floor. For example, an engineered walnut floor will have several layers of wood and a top walnut lamella.

In archaeology, the term is used for a variety of small flat and thin objects, such as Amulet MS 5236, a very thin gold plate with a stamped text from Ancient Greece in the 6th century BC.

In crystallography, the term was first used by Christopher Chantler and refers to a very thin layer of a perfect crystal, from which curved crystal physics may be derived.

In textile industry, a lamella is a thin metallic strip used alone or wound around a core thread for goldwork embroidery and tapestry weaving.

In September 2010, the U.S. Food and Drug Administration (FDA) announced a recall of two medications which contained "extremely thin glass flakes (lamellae) that are barely visible in most cases. The lamellae result from the interaction of the formulation with glass vials over the shelf life of the product."

See also

Lamella (cell biology)
Middle lamella
Annulate lamella
Lamella (structure)

References

Materials science
ISF. ISF may stand for:

Science and technology
Imaging Science Foundation
Impulse sensitivity function
Incremental sheet forming
Information Security Forum, an international information security best practices organization
Ingenieurs Sans Frontieres (Engineers Without Borders)
Ink Serialized Format, a vector image file format from Microsoft
Interstitial fluid
Israel Science Foundation

Education
Idries Shah Foundation, educational charity
Independent Schools Foundation Academy, private international school in Hong Kong
 Insaf Student Federation, it is the largest Center-Left Student organization in the Nation and the official student wing of the Pakistan Tehreek-e-Insaf political party
International School of Florence
International School Sport Federation, sports governing body for high school sport
Internationale Schule Frankfurt Rhein-Main

Sport
International Snowboard Federation
International Softball Federation
International Skyrunning Federation, world sports governing body for skyrunning
International Socca Federation, governing body of small-sided-football
International Sumo Federation, governing body for amateur sumo

Other
Idaho Shakespeare Festival, theater company
Importer Security Filing
Impôt de Solidarité sur la Fortune, a French wealth tax
Indian Secular Front
Information Support Force, a service branch of the People's Liberation Army
Internal Security Forces, of Lebanon
International Seafarers' Federation, former international trade secretariat
Iraqi security forces
Italian Strategic Fund
Lexus IS F
Mather Stock Car Company. The Mather Stock Car Company was a U.S. corporation that built railroad rolling stock.  Mather specialized in stock cars, but built other types of cars as well, including boxcars.  The company was headquartered in Chicago, Illinois.  Their main headquarters building, Mather Tower, built in 1928 in Chicago, still stands today.  This building has the smallest floors of any of Chicago's skyscrapers.

History
Mather was founded by Alonzo C. Mather; the company's first stock car was built in 1880.  As the 20th century dawned, Mather began leasing stock cars to the railroads that used them.  Railroads of the time found it less expensive to lease stock cars than to purchase them outright or to build them.  By the 1920s, Mather had expanded their fleet to include boxcars and refrigerator cars along with a few tank cars.

With the onset of the Great Depression in the US, Mather was one of a limited number of companies that saw profits in the 1930s.  As railroads eliminated freight cars out of their own fleets, leasing companies such as Mather were able to step in and supply freight cars as needed.

In the late 1950s Mather was merged into the North American Car Corporation of Chicago.

Preservation
Several examples of Mather's stock cars exist in museums, but only eight of the hundreds of box cars that Mather built survive to this day.  One, Akron, Canton and Youngstown Railroad #3024, is owned by the Pacific Southwest Railway Museum Association (operators of the San Diego Railroad Museum), while the remaining seven are owned by the Mid-Continent Railway Museum in North Freedom, Wisconsin.

References

 Emporis (2004), .  Retrieved March 23, 2005.
 Mid-Continent Railway Museum, Akron Canton & Youngstown #3011.  Retrieved March 24, 2005.
 Pacific Southwest Railway Museum Association (1992), Akron, Canton and Youngstown #3024. Retrieved March 23, 2005
 Pacific Western Rail Systems (2003), Mather Meat Refrigerator Cars.  Retrieved March 24, 2005.

Defunct rolling stock manufacturers of the United States
History of Chicago
BMW 132. The BMW 132 was a nine-cylinder radial aircraft engine produced by BMW starting in 1933.

Design and development
BMW took over a license for manufacturing air-cooled radial engines from Pratt & Whitney on 3 January 1928. The nine-cylinder model Pratt & Whitney R-1690 Hornet was initially manufactured virtually unchanged under the designation BMW Hornet.

Soon BMW embarked on its own development. The result was the BMW 132, essentially an improved version of the Hornet engine, that went into production in 1933. A number of different versions were built; aside from the carburetor designs used mainly in civilian aircraft, versions with direct fuel injection were manufactured for the German Luftwaffe. The engines had a displacement of  and generated from  to  depending on model.

The 132 found widespread use in the transport role, remaining the primary powerplant of the Junkers Ju 52 for much of its life, turning the BMW 132 into one of the most important aircraft engines for civilian aircraft during the 1930s.

Numerous pioneering flights were undertaken with the BMW 132. The most impressive was the first direct flight from Berlin to New York in a four-engined Focke-Wulf 200 S-1 Condor. It covered the distance to New York in 24 hours and 57 minutes on 10 August 1938.

Variants
132A 
132Dc
132De
132J/K with higher rpm
132N
132T
132W
ENMA Beta B-4 (Spanish license-built version)(9E-C29-775)  (stroke , displacement )

Applications
 Arado Ar 195
 Arado Ar 196
 Arado Ar 197
 Blohm & Voss Ha 140
 Blohm & Voss BV 141
 Blohm & Voss BV 142
 Dornier Do 17P
 Fieseler Fi 98
 Focke-Wulf Fw 200 Condor
 Heinkel He 114
 Heinkel He 115
 Henschel Hs 123
 IAR 38
 Junkers W 34
 Junkers Ju 52
 Junkers Ju 86
 Junkers Ju 90
 Junkers Ju 160

Specifications (BMW 132 Dc)

See also

References

Bibliography

External links

Aircraft air-cooled radial piston engines
BMW aircraft engines
1930s aircraft piston engines
OK (dinghy). The OK Dinghy is an international class sailing dinghy, designed by Knud Olsen in 1956.

History
In 1956 Axel Damgaard Olsen of Vordingborg, asked the Danish yacht designer Knud Olsen to prepare drawings for a light and fast single-handed sailing dinghy based on conventional plywood construction.  The resulting design was named the "OK", using Knud Olsen's initials in reverse.

The OK was intended as a preparation class for the Olympic Finn and it has followed its technical evolution ever since.  The rig is identical to a Finn comprising a single sail set on a rotating, un-stayed, bending mast.

OKs are built in plywood, G.R.P and composite construction; all forms enjoy equal racing success.  Freedom of choice in hull materials is replicated in choice of rig.  The choice of mast, sail and fittings must fit within the class rules but enables all sailors to have a combination suited to their own requirements.  Consequently, every OK develops to suit the owner's style of sailing, while the shape of the hull is defined by a comprehensive set of strict one-design rules ensuring a long competitive life span.  Old boats often only need a rig update and minor constructional modifications to make them competitive, provided they meet modern buoyancy requirements.

In the 60s and 70s, the OK class enjoyed an explosive success, with the total number of boats exceeding 10,000, and large racing fleets building up.  In the 80s, the success of the popular one-design single-handed Laser affected the success of the OK.

In the eastern European countries, the OK was the official youth single hander and after the breakdown of the USSR, many 'old' sailors came back to the class of their youth, now with their own boats instead of club-owned.

The OK Dinghy was selected as the Open class single hander for the Asian Games 1998.

In 2003 carbon fibre masts were introduced to the class.

In 2005, there was a revival of the OK class with many older boats being restored and updated, new boats being built and participation in club races rising.

The 50th anniversary of the design of the OK dinghy was marked by the largest ever OK Dinghy World Championships held at Łeba on the Polish coast in July 2007.

Events

World Championships

See also
Knud Olsen

References

External links

OK Dinghy - International Association
 ISAF OK Dinghy Microsite

 
Classes of World Sailing
Dinghies
1950s sailboat type designs
Sailboat type designs by Danish designers
Sailboat types built by Clark Boat Company
Computing with words and perceptions. In computing with words and perceptions (CWP), the objects of computation are words, perceptions, and propositions drawn from a natural language.  The central theme of CWP is the concept of a generalised constraint.  The meaning of a proposition is expressed as a generalised constraint.

CWP is a necessary tool when the available information is perception-based or not precise enough to use numbers.

See also
Fuzzy set
Lotfi Zadeh
Perceptual computing
Type-2 fuzzy sets and systems

References

 L. A. Zadeh, “Fuzzy logic = computing with words,” IEEE Trans. on Fuzzy Systems, vol. 4, pp. 103-111, 1996.

Soft computing
IPEC. IPEC can refer to:
 Indian Point Energy Center
 International Programme on the Elimination of Child Labour
 Institute of Permaculture and Ecovillage of the Cerrado, Brazil
 Inteligência em Pesquisa e Consultoria Estratégica, a Brazilian opinion polling company
 Intellectual Property Enterprise Court, a venue for legal actions relating to Intellectual Property in the United Kingdom 
 International Pharmaceutical Excipients Council
 International Symposium on Parameterized and Exact Computation, an annual computer science conference
 Toll Ipec, an Australian logistics enterprise, subsidiary of Toll Group

See also

 Ipek (disambiguation)
Refinement (computing). Refinement is a generic term of computer science that encompasses various approaches for producing correct computer programs and simplifying existing programs to enable their formal verification.

Program refinement
In formal methods, program refinement is the verifiable transformation of an abstract (high-level) formal specification into a concrete (low-level) executable program. Stepwise refinement allows this process to be done in stages. Logically, refinement normally involves implication, but there can be additional complications.

The progressive just-in-time preparation of the product backlog (requirements list) in agile software development approaches, such as Scrum, is also commonly described as refinement.

Data refinement
Data refinement is used to convert an abstract data model (in terms of sets for example) into implementable data structures (such as arrays). Operation refinement converts a specification of an operation on a system into an implementable program (e.g., a procedure). The postcondition can be strengthened and/or the precondition weakened in this process. This reduces any nondeterminism in the specification, typically to a completely deterministic implementation.

For example, x ∈ {1,2,3} (where x is the value of the variable x after an operation) could be refined to x ∈ {1,2}, then x ∈ {1}, and implemented as x := 1. Implementations of x := 2 and x := 3 would be equally acceptable in this case, using a different route for the refinement. However, we must be careful not to refine to x ∈ {} (equivalent to false) since this is unimplementable; it is impossible to select a member from the empty set.

The term reification is also sometimes used (coined by Cliff Jones). Retrenchment is an alternative technique when formal refinement is not possible. The opposite of refinement is abstraction.

Refinement calculus
Refinement calculus is a formal system (inspired from Hoare logic) that promotes program refinement. The FermaT Transformation System is an industrial-strength implementation of refinement. The B-Method is also a formal method that extends refinement calculus with a component language: it has been used in industrial developments.

Refinement types

In type theory, a refinement type is a type endowed with a predicate which is assumed to hold for any element of the refined type.  Refinement types can express preconditions when used as function arguments or postconditions when used as return types:  for instance, the type of a function which accepts natural numbers and returns natural numbers greater than 5 may be written as .  Refinement types are thus related to behavioral subtyping.

See also
 Reification (computer science)

References

Formal methods terminology
Computer programming
Curtiss-Wright X-19. The Curtiss-Wright X-19, company designation Model 200, is an American experimental tiltrotor aircraft of the early 1960s. It was noteworthy for being the last aircraft of any kind manufactured by Curtiss-Wright.

Design and development
In March 1960 the Curtiss-Wright Corporation developed the X-100, a prototype for a new, vertical takeoff transport aircraft. The X-100 had a single turboshaft engine, which propelled two tilting-propellers, while at the tail swivelling nozzles used the engine's exhaust gases to give additional control for hovering or slow flight. Although sometimes classified as a tiltrotor aircraft, the design differed from the Bell VTOL XV tiltrotor designs. The X-19 utilized specially designed radial lift propellers, rather than helicopter-like rotors, for vertical takeoff and augmenting the lift provided by the wing structures.

From the X-100 Curtiss-Wright developed the larger X-200, of which the United States Air Force ordered two prototypes designated the X-19A.

The X-19 had fore and aft high-mounted tandem wings. Each wing mounted two  propellers that could be rotated through 90 degrees, allowing the aircraft to take off and land like a helicopter. The propellers were driven by twin Avco Lycoming T55-L-5 turboshaft engines mounted in the fuselage.

Operational history
The first flight of the X-19 took place in November 1963 (other sources give 26 June 1964). It was intended that the X-19 would be developed into a VTOL transport aircraft. However the first X-19 was destroyed in a crash on 25 August 1965, with no loss of life, and the program was subsequently cancelled; the second prototype was never completed. The second X-19 prototype is currently being stored in the restoration facilities at the National Museum of the United States Air Force in Dayton, Ohio.

The power transmission, power to weight requirements, flight mode transition and multi-axis control make VTOL aircraft design far more problematic than conventional fixed wing and even helicopter design. Like most pioneering tilt aircraft, the aerodynamic complexity of coupled pitch, roll, and yaw, and torque, particularly in transition from vertical takeoff to horizontal flight, made design of the X-19 extremely challenging. Ultimately, weaknesses in the power transmission gear boxes led to failure. Owing to design complexity, tiltrotor VTOL aircraft did not enter operational service until the Bell-Boeing V-22 Osprey introduction in 2007.

Specifications (X-19)

See also

References

External links

 Curtiss-Wright X-19 Background

Tandem-wing aircraft
Tiltrotor aircraft
X-19, Curtiss-Wright
X-19
Quadrotors
Aircraft first flown in 1963
Aircraft with retractable tricycle landing gear
Twin-engined four-prop tractor aircraft
Turboshaft-powered aircraft
Trigonal pyramidal molecular geometry. In chemistry, a trigonal pyramid is a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base, resembling a tetrahedron (not to be confused with the tetrahedral geometry). When all three atoms at the corners are identical, the molecule belongs to point group C3v. Some molecules and ions with trigonal pyramidal geometry are the pnictogen hydrides (XH3), xenon trioxide (XeO3), the chlorate ion, , and the sulfite ion, . In organic chemistry, molecules which have a trigonal pyramidal geometry are sometimes described as sp3 hybridized. The AXE method for VSEPR theory states that the classification is AX3E1.

Trigonal pyramidal geometry in ammonia 

The nitrogen in ammonia has 5 valence electrons and bonds with three hydrogen atoms to complete the octet. This would result in the geometry of a regular tetrahedron with each bond angle equal to arccos(−) ≈ 109.5°. However, the three hydrogen atoms are repelled by the electron lone pair in a way that the geometry is distorted to a trigonal pyramid (regular 3-sided pyramid) with bond angles of 107°. In contrast, boron trifluoride is flat, adopting a trigonal planar geometry because the boron does not have a lone pair of electrons. In ammonia the trigonal pyramid undergoes rapid nitrogen inversion.

See also
VSEPR theory#AXE method
Molecular geometry

References

External links
Chem| Chemistry, Structures, and 3D Molecules 
Indiana University Molecular Structure Center
 Interactive molecular examples for point groups
Molecular Modeling
Animated Trigonal Planar Visual

Molecular geometry
Radius gauge. A radius gauge, also known as a fillet gauge, is a tool used to measure the radius of an object.

Radius gauges require a bright light behind the object to be measured.  The gauge is placed against the edge to be checked and any light leakage between the blade and edge indicates a mismatch that requires correction.

A good set of gauges will offer both convex and concave sections, and allow for their application in awkward locations.

Every leaf has a different radius, for example with radius intervals of 0.25 mm or 0.5 mm. The material of the leaves is stainless steel. Each gauge is one of two types; either internal or external, which are used to check the radius of inner and outer surfaces, respectively.

See also 
 Thread pitch gauge
 Spherometer, an instrument for the precise measurement of radiuses

References

Notes

Bibliography
.
.

Dimensional instruments
Metalworking measuring instruments
Radii
Mannitol hexanitrate. Mannitol hexanitrate is a powerful explosive.  Physically, it is a powdery solid at normal temperature ranges, with density of 1.73 g/cm3. The chemical name is hexanitromannitol and it is also known as nitromannite, MHN, and nitromannitol, and by the trademarks Nitranitol and Mannitrin. It is more stable than nitroglycerin, and it is used in detonators.

Mannitol hexanitrate is a secondary explosive formed by the nitration of mannitol, a sugar alcohol. The product is used in medicine as a vasodilator and as an explosive in blasting caps. Its sensitivity is high, particularly at high temperatures (> 75 °C) where it is slightly more sensitive than nitroglycerine. Nitromannite is a class B explosive.

The production of pure MHN is not a trivial task, since most preparations will yield a mixture of MHN and lower esters (pentanitrate and lower).

See also
 Pentaerythritol tetranitrate (PETN)
 Xylitol pentanitrate
 Erythritol tetranitrate (ETN)
 Ethylene glycol dinitrate
 Methyl nitrate

References

 The Chemistry of Powder and Explosives, Tenney L. Davis

External links
 Powerlabs.org

Explosive chemicals
Nitrate esters
Sugar alcohol explosives