omniomni/omni-engineering huggingface dataset:
Rotax 503. The Rotax 503 is a , inline 2-cylinder, two-stroke aircraft engine, built by BRP-Rotax GmbH & Co. KG of Austria for use in ultralight aircraft.

For decades the engine was one of the most popular and reputedly reliable aircraft engines in its class (two-stroke, under 60 horsepower), and it remains widely used and supported.

As of 2011 the Rotax 503 is no longer in production. However, a Russian manufacturer has developed an approximate reproduction, the RMZ 500.  Rotax subsequently offered only one other two-stroke engine for aircraft, the partially water-cooled Rotax 582.

Design and development

The Rotax 503 is piston ported with air-cooled cylinders and heads, utilizing either an engine driven fan and cowl, or free air cooling. Lubrication is either by use of pre-mixed fuel and oil or oil injection from an externally mounted oil tank. The 503 has dual independent breakerless, magneto capacitor-discharge ignition (CDI) systems. It can be equipped with either one or two piston-type carburetors. It uses a manifold-driven pneumatic fuel pump to provide fuel pressure. An optional High Altitude Compensation kit is available.

The engine's propeller drive is via a Rotax type B, C, or E style gearbox. The standard engine includes a muffler exhaust system with an extra after-muffler as optional. The standard starter is a recoil start type, with an electric starter optional. An integral alternating current generator producing 170 watts at 12 volts with external rectifier-regulator is optional. The engine includes an intake air filter and can be fitted with an intake silencer system.

Limitations
Rotax recommends teardown and inspection every 150 hours, and overhaul every 300 hours.

The manufacturer acknowledges the design limitations of this engine, warning pilots:

Applications

Specifications (503)

References

External links

Air-cooled aircraft piston engines
Rotax engines
Two-stroke aircraft piston engines
Stephen Michael Elonka. Stephen Michael Elonka (died 1983) was the author of numerous technical books, including Standard Plant Operators' Manual. He also wrote a book of the adventures of one Marmaduke Surfaceblow, a fictional engineer who solves difficult problems in ingeniously simple ways. POWER Magazine's  Marmaduke Awards were named for this character.  Books by Elonka have been translated into Spanish, Portuguese, and Chinese.

Notes

Year of birth missing
1983 deaths
Rotax 447. The Rotax 447 is a , inline 2-cylinder, two-stroke aircraft engine, built by BRP-Rotax GmbH & Co. KG of Austria for use in ultralight aircraft.

Design and development

The Rotax 447 is a development of the Rotax 377, increasing the power output from  to  by increasing the cylinder bore from 62 mm to 67.5 mm and the maximum rpm from 6500 to 6800. The modern 447 has a single breakerless, magneto capacitor-discharge ignition (CDI) system. Early (ca. 1988) models use a breaker point ignition system.

The Rotax 447 features piston-ported, air-cooled cylinder heads and cylinders, utilizing either a fan or free air for cooling. Lubrication is by use of pre-mixed fuel and oil. The engine can be equipped with either one or two piston-type float carburetors. The dual-carburetor version uses Bing model 84 carburetors. The single-carburetor version uses a Bing model 54 carburetor.  An optional High Altitude Compensation kit is available. It is typically installed with an induction-pulse-driven diaphragm fuel pump to provide fuel pressure.

The engine's propeller drive is via a Rotax type B gearbox. The standard engine includes a muffler exhaust system with an extra after-muffler as optional. The standard starter is a recoil start type, with an electric starter optional. An integral alternating current generator producing 170 watts at 12 volts with external rectifier-regulator is optional. The engine includes an intake air filter and can be fitted with an intake silencer system.

The manufacturer acknowledges the design limitations of this engine, warning pilots:

Variants
447 UL-1V
basic engine equipped with a single carburettor,  at 6800 rpm
447 UL-2V
basic engine equipped with two carburettors,  at 6800 rpm

Applications

Specifications (447)

References

Rotax engines
Air-cooled aircraft piston engines
Two-stroke aircraft piston engines
Ground Mobile Forces. Ground Mobile Forces (GMF) is the term given to the tactical SATCOM portion of the Joint Service program called TRI-TAC developed by GTE-Sylvania in the mid-1970s. The Tri-Service Tactical signal system is a tactical command, control, and communications program. It is a joint service effort to develop and field advanced tactical and multichannel switched communications equipment. The program was conceived to achieve interoperability between service tactical communications systems, establish interoperability with strategic communications systems, take advantage of advances in technology, and eliminate duplication in service acquisitions.

Specifications
GMF is configured in a hub-spoke arrangement with the hub terminal being able to ingest four feeds from the outlying spoke terminals. Of the four designated GMF terminals, the AN/TSC-85B and AN/TSC-100A are equipped for point-to-point or hub operations and the AN/TSC-93B and AN/TSC-94A are spoke terminals.

The 85B/100A hubs are capable of ingesting up to 48 multiplexed and encrypted channels from a maximum of four spoke terminals simultaneously, but can double that capability with an external multiplexer (96 channels). Each channel is configured for 16 or 32 kbit/s, which with overhead translates to 48 kbit/s true capacity. The 93B/94A terminals have a capacity of 24 16/32 kbit/s multiplexed channels. All of the GMF terminals have external connections for an AN/TSQ-111 Tech Control Facility, field phones, or a  IF wideband input, plus are sealed for sustained operations in a chemical/biological/radiological (CBR) environment.

GMF communicates via Super High Frequency (SHF) X-band Defense Satellite Communication System (DSCS) satellites. The 85B/100A hub terminals typically use a . Quick Reaction Satellite Antenna Group (QRSAG) antenna, while the outlying spoke terminals rely on an  parabolic dish antenna.

Obsolescence
Today, much of the TRI-TAC and GMF equipment is obsolete – its bulky circuit-switched equipment having been replaced in the last decade by fly-away quad-band systems containing compact IP-based routers, switches, and encryption equipment. There were, however, a number of GMF terminals still supporting active forces in the extreme operating conditions of Iraq and Afghanistan.

References

Further reading

Communications satellites
Aerospace Education Services Project. Aerospace Education Services Project (AESP) is a NASA education project which delivers science, technology, engineering, and mathematics (STEM) professional development to K-12, pre-service, and informal educators providing classroom demonstrations, distance learning events, in-service training for educators and pre-service training for college students. Through utilization of NASA products and materials, AESP helps students understand how STEM content is relevant to them by using real-world and engaging materials in their classroom and encourages them to pursue a career in NASA or other STEM careers. The project has education specialists working at all of the NASA centers across the U.S. These educators work with schools and other organizations in order to deliver professional learning opportunities through both face-to-face and virtual venues. The project is managed by Kyle Peck, Principal Investigator, Peggy Maher, Director and Dan Cherry, NASA Project Manager at the Langley Research Center.

Programs 

Robots on the Road (ROTR) is an educational program run by traveling NASA specialists in middle schools across the country. Students in grades 5-8 work in groups in order to determine what their robot is designed to do, and how it uses its motors and sensors to achieve those goals. The robots used in this program are made from Lego Mindstorms kits, and are analogous to existing NASA robots.

References 

AESP Homepage
NASA's Aerospace Education Services Project

NASA groups, organizations, and centers
Micromachining. Micromachining may refer to:

The technique for fabrication of 3D and 2D structures on the micrometer scale.
Superfinishing, a metalworking process for producing very fine surface finishes
Various microelectromechanical systems
Bulk micromachining
Surface micromachining
High-aspect-ratio microstructure technologies

See also
High aspect ratio (HAR) silicon micromachining
Tupolev ANT-22. 

The Tupolev ANT-22 (also known as the MK-1) was a large flying boat built in the Soviet Union in 1934. A huge aircraft consisting of two hulls and powered by six engines in three nacelles in a push-pull configuration, it was based on the ANT-11, which was never built. Its enormous weight severely crippled its performance, and it never proceeded beyond the experimental stage.

Operators
 
 Soviet Naval Aviation

Specifications (ANT-22)

Notes

References

 

1930s Soviet patrol aircraft
Flying boats
ANT-22
Six-engined push-pull aircraft
Twin-fuselage aircraft
Aircraft first flown in 1934
Twin-tail aircraft
1,3,5-Trinitrobenzene. 1,3,5-Trinitrobenzene is one of three isomers of trinitrobenzene with the formula C6H3(NO2)3. A pale yellow solid, the compound is highly explosive.

Synthesis and reactions
1,3,5-Trinitrobenzene is produced by decarboxylation of 2,4,6-trinitrobenzoic acid.

1,3,5-Trinitrobenzene forms charge-transfer complexes with electron-rich arenes.

Reduction of 1,3,5-trinitrobenzene gives 1,3,5-triaminobenzene, a precursor to phloroglucinol.

Uses and applications
Trinitrobenzene is more explosive than TNT, but more expensive. It is primarily used as a high explosive compound for commercial mining and military applications. It has also been used as a narrow-range pH indicator, an agent to vulcanize natural rubber, and a mediating agent to mediate the synthesis of other explosive compounds.

See also
 1,2,3-Trinitrobenzene
 TNT equivalent
 RE factor

References

Nitrobenzenes
Explosive chemicals
Hexanitrodiphenylamine. Hexanitrodiphenylamine (abbreviated HND), is an explosive chemical compound with the formula C12H5N7O12. Since it is made from readily available raw materials, HND was used extensively by the Japanese and less extensively by Nazi Germany during World War II but was discontinued due to its toxicity.

Preparation
Dinitrodiphenylamine is treated with 98% nitric acid. The starting material, dinitrodiphenylamine, is obtained from the reaction of aniline, dinitrochlorobenzene, and soda ash.

Applications
HND is a booster-class explosive that was used in World War II by the Germans as a component of Hexanite (60% TNT - 40% HND) and by the Japanese as a component of Kongo (Type 98 H2) (60% Trinitroanisole - 40% HND) for use in bombs, sea mines and depth charges; Seigate (Type 97 H) (60% TNT - 40% HND) for use in torpedo warheads and depth charges; and also in Otsu-B (60% TNT, 24% HND & 16% aluminium powder) for use in torpedo warheads.

Its ammonium salt, also known as Aurantia or Imperial Yellow, was discovered in 1873 by Emil Kopp and used as a yellow colorant for leather, wool and silk in the 19th and early 20th centuries.

Safety and toxicity
A most toxic and poisonous explosive, it attacks the skin, causing blisters which resemble burns. Dust from HND is injurious to the mucous membranes of the mouth, nose, and lungs. Several nitroaromatic explosives, including HND, have been found to be mutagens.

Incidents
On 12 May 2022, construction of the Bundesautobahn 49 in Germany was halted, after traces of the explosive were found in the excavated material. The road passes over a former explosives factory near Stadtallendorf. The factory had been demolished after World War II, and it was not expected that traces of explosives had remained in the ground.

See also
 Hexanite

References

Explosive chemicals
Nitrobenzene derivatives
Anilines
Hash consing. In computer science, particularly in functional programming, hash consing is a technique used to share values that are structurally equal. When a value is constructed, such as a cons cell, the technique checks if such a value has been constructed before, and if so reuses the previous value, avoiding a new memory allocation. A useful property of hash consing is that two structures can be tested for equality in constant time via pointer equality, which in turn can improve efficiency of divide and conquer algorithms when data sets contain overlapping blocks. Hash consing has been shown to give dramatic performance improvements—both space and time—for symbolic and dynamic programming algorithms. 

Hash consing is most commonly implemented with hash tables storing weak references that may be garbage-collected when the data stored therein contains no references from outside the table.

Example

Simple, not very efficient, but suitable for demonstration of the concept implementation of a memoizer by means of hash table and weak references in Scheme:

;; weak hashes
;;
(require 'hash-table)

(define (make-weak-table . args)
  (apply make-hash-table args))

(define (weak-table-set! table key data)
  (let ((w (hash-table-ref table key #f)))
    (if w
        (vector-set! w 0 data)
      (let ((w (make-weak-vector 1)))
        (vector-set! w 0 data)
        (hash-table-set! table key w)))))

(define (weak-table-ref table key)
  (let ((w (hash-table-ref table key #f)))
    (if w
        (vector-ref w 0)
      #f)))

;; memoizer factory: for given (side-effect-free) procedure,
;; return a procedure which does the same memoizing some of results
;; in the sense of equal? on the whole list of args
;;
(define (make-weak-memoizer proc)
  (let ((cache (make-weak-table equal?)))
    (lambda args
      (let ((x (weak-table-ref cache args)))
        (if (bwp-object? x)
            (let ((r (apply proc args)))
              (weak-table-set! cache args r)
              r)
          x)))))

History

A hash consing compilation technique was presented by A.P. Ershov in 1958. The term "hash consing" originates from implementations in the context of Lisp in the 1970s.

See also
String interning
Flyweight pattern
 Merkle tree
 Hashlife
 Interning

References

Further reading
 
 Jean Goubault. Implementing Functional Languages with Fast Equality, Sets and Maps: an Exercise in Hash Consing. In Journées Francophones des Langages Applicatifs (JFLA’93), pages 222–238, Annecy, February 1993.

Implementation of functional programming languages
Hashing
Articles with example Scheme (programming language) code
SimSpark. SimSpark is a generic simulation system for various multiagent simulations. It supports developing physical simulations for AI and robotics research with an open-source application framework.  It is commonly used in academic research and education.

History 
The SimSpark project started in 2003 and was based on the building blocks of the Spark project.  It was initially developed by Marco Kögler and Oliver Obst at the University of Koblenz-Landau in Koblenz, Germany.

SimSpark was registered with SourceForge in 2004 and has an established code base with development increasing year-over-year.

Architecture 
Agents communicate with the simulation server via UDP or TCP, and therefore can be implemented in any language that supports such sockets.  Multiple software agents can participate in one simulation.

Simulations are created within the server using the Ruby language and text-based RSG files.  
SimSpark uses the Open Dynamics Engine (ODE) for detecting collisions and for simulating rigid body dynamics.  ODE allows accurate simulation of the physical properties of objects such as velocity, inertia and friction.

Use in RoboCup 

SimSpark is the simulation engine for the RoboCup 3D Soccer Simulation League. In this simulation two teams play soccer with rules similar to regular soccer. The robots use simulated cameras and other sensors such as accelerometers, gyros and touch and audio sensors.  Software agents process signals from these sensors (also known as perceptors) and generate control signals for the 22 hinges within each robot's body in order to achieve whatever forms of motion are required to win a game of soccer.

The original soccer robot model was known as soccerbot, but since 2008 it has been replaced with a Nao robot inspired model.

References

External links 
 Project Homepage
 GitLab Page
 SourceForge home page
 SourceForge project page
 SimSpark Wiki
 SimSpark project on ohloh

Robotics simulation software
Educational software
2003 software
2003 in robotics
Reflectometric interference spectroscopy. Reflectometric interference spectroscopy (RIfS) is a physical method based on the interference of white light at thin films, which is used to investigate molecular interaction.

Principle
The underlying measuring principle corresponds to that of the Michelson interferometer.

Realization
 
White light is directed vertically onto a multiple-layer system of a SiO2, a high-refractive Ta2O5 and an additional SiO2 layer (this additional layer can be chemically modified). The partial beams of the white light are reflected at each phase boundary and then refracted (transmitted). These reflected partial beams superimpose which results in an interference spectrum that is detected using a diode array spectrometer.
Through chemical modification the upper SiO2 layer is changed in a way to allow interaction with target molecules. This interaction causes a change in the thickness of the physical layer d and the refractive index n within this layer. The product of both defines the optical thickness of the layer: n • d.
A change in the optical thickness results in a modulation of the interference spectrum. Monitoring this change over time allows to observe the binding behaviour of the target molecules.

Application
 
RIfS is used especially as a detection method in chemo- and biosensors.

Chemosensors are particularly suitable for measurements under difficult conditions and in the gaseous phase. As sensitive layers, mostly non-selective measuring polymers are used which sort the analytes according to size (the so-called molecular sieve effect when using microporous polymers) or according to polarity (e.g. functionalized polydimethylsiloxanes). When performing non-selective measurements, a sum signal from several analytes is measured which means that multivariate data analyses such as neural networks have to be used for quantification. However, it is also possible to use selectively measuring polymers, so-called molecular imprinted polymers (MIPs) which provide artificial recognition elements.

When using biosensors, polymers such as polyethylene glycols or dextrans are applied onto the layer system, and on these recognition elements for biomolecules are immobilized. Basically, any molecule can be used as recognition element (proteins such as antibodies, DNA/RNA such as aptamers, small organic molecules such as estrone, but also lipids such as phospholipid membranes).

RIfS, like SPR is a label-free technique, which allows the time-resolved observation of interaction among the binding partners without the use of fluorescence or radioactive labels.

Literature
 G. Gauglitz, A. Brecht, G. Kraus and W. Nahm. Sensor. Actuat. B-Chem. 11, 1993
 A. Jung. Anal. Bioanal. Chem. 372 1, 2002
 F. Gesellchen, B. Zimmermann, F. W. Herberg. Methods in Molecular Biology, 2005
 T. Nagel, E. Ehrentreich-Forster, M. Singh, et al. Sensors and Actuators B-Chemical 129 2, 2008
 P. Fechner, F. Pröll, M. Carlquist and G. Proll. Anal. Bioanal. Chem. Nov 1, 2008

External links
 Barolo.ipc.uni-tuebingen.de

Spectroscopy
Carlo Borer. Carlo Borer (born March 23, 1961, in Solothurn) is a Swiss artist and designer.

Works 
Carlo Borer is deliberately autodidact as an artist. He has been working freelance since 1981, beginning with figurative paintings, drawings, and three-dimensional works made of polyester and electrical light. Since 1991, he has been building objects out of stainless steel or aluminum. And in 1999, he started using 3D computer graphics to design, develop, and construct sculptures, installations, furniture and utilitarian objects, such as espresso machines, ventilators, and mailboxes. A laser is used to cut the forms out of the sheet metal, which are then rounded off and welded. Borer refers to works that have come about like this as Transformers, Loops, and Clouds. Though Borer takes his inspirations for his No Readymades and his Spaceships from pieces he has found, nevertheless, he creates the works as complex forms in virtual reality by means of CAD systems that have been further developed especially for this.

Carlo Borer lives in Wanzwil, and maintains his studio in Zuchwil.

Selected exhibitions 
 1990 : Kunstmuseum Solothurn, Solothurn
 1997 : BHG Gallery, Los Angeles – Sinking Cities
 2004 : Stadt Solothurn - The Big Loop
 2009 : 4.th Swiss Triennial Festival of Sculpture, Bad RagARTz in Bad Ragaz and Vaduz
 2010 : art station, Zurich – 2structures
 2010 : Stiftung SkulptUrschweiz, Ennetbürgen-Luzern
 2010 : BeGe Galerien, Ulm
 2010 : Nord Art in Büdelsdorf
 2011 : Nord Art in Büdelsdorf
 2011 : Kulturforum Würth Chur, Chur – Thinking Shape

Commissions visible in public 
 2002 : Object No. 333, Saint-Blaise NE,
 2007 : Object No. 397, Ennetbüren-Luzern 
 2009 : Object No. 401, Hilti Foundation, Schaan
 2011 : Object No. 370, Kulturforum Würth Chur

Selected literature 
 Catalogue Werkjahrbeiträge des Kantons Solothurn (1989) - Kantonales Kuratorium für Kulturförderung, Solothurn
 KVS Cultura, Ittigen, Issue 1 (1991)
 Peculiar Geometries, (Sculpture Vol. 27 No. 10, 2008): article by Peter Lodermeyer 
 Kunst Vol. 4 (2011)

References

External links 
 Carlo Borer’s official website
 Carlo Borer’s own website

1961 births
Living people
20th-century Swiss sculptors
20th-century Swiss male artists
21st-century Swiss sculptors
Swiss designers
20th-century Swiss painters
Swiss male painters
21st-century Swiss painters
21st-century Swiss male artists