omniomni/omni-engineering huggingface dataset:
Cast acrylic. Cast Acrylic is a form of poly(methyl methacrylate) (PMMA). It is formed by casting the monomer, methyl methacrylate, mixed with initiators and possibly other additives into a form or mold. Sheet and rod stock are generated by casting into static forms, while tubing is done in rotational molds.

Advantages 

It has better thermal stability, higher resistance to crazing when exposed to solvents, wider thermoforming range than extruded acrylic. Cast acrylic has a better ability to be reworked hot and it is known for its superior surface finish and optical properties. Also cast acrylic is more scratch resistant than extruded acrylic.
Cast acrylic is also preferred over extruded in applications that require machinings, such as turning on Engine Lathe or milling/drilling. Extruded acrylic, with far less thermal stability, tends to melt and clog cutting tools. Even with slow speeds and much coolant, extruded acrylic does not produce the surface finish and tight tolerances achievable with cast acrylic.

Properties 
Advantages of Acrylic (PMMA):
Excellent optical clarity and transparency
Highly resistant to variations in temperature
Up to 17 times the impact resistance of ordinary glass
Half the weight of glass and ideal for precision machining
Highly resistant to many different chemicals
Has certain properties making it an ideal material for use in a wide range of applications, including medical, life sciences and food/beverage testing.

PMMA – PolyMethyl MethAcrylate.  Crylux, Plexiglas, Acrylite, Lucite, and Perspex are trade names for Acrylic.

Technical specification 
General Properties: 
Relative Density 1.19 g/cm3 
Rockwell Hardness M 102 
Water Absorption 0.2% 
Flammability Class 3 (BS 476 pt 7), UL94 HB
Mechanical: 
Tensile Strength 75 MPa 
Flexural Strength 115 MPa
Thermal Properties: 
Minimum Service Temperature -40°C 
Maximum Service Temperature 80°C 
Softening Point >110°C 
Linear Expansion 7.7×10-5
Optical Properties: 
Light Transmission >92% 
Refractive Index 1.49

Usage 

This type of acrylic is often used for aquariums, awards, financial tombstones, trophies, corporate gifts, and other products that require shaping or machining. It tends to be more clear and made to a higher quality standard, but in doing so makes it more expensive than extruded acrylic.

References

See also

 Financial tombstone
 Acrylic embedment

Plastics industry
Jeep Willys2. The Jeep Willys2 is a concept car made by the Chrysler Group and presented at the 2001 Tokyo Auto Show. The Willys2 is based on the Willys MB and uses frame web technology and a one-piece carbon-fiber body. The design takes many design cues from other Jeep models, such as the seven-slot grille and trapezoidal wheel arches. Some elements of the design were later incorporated into the Jeep Liberty. The Willys2 weighs around 3000 pounds with its removable carbon-fiber top. Its powered by a 160-hp I4 engine, which accelerates it from 0 to 60 mph in 10 seconds, and onto a top speed of about 90 mph. The interior is all plastic, and it is possible to clean the interior by spraying it with water.

References

Willys2
Fournier RF 3. The Fournier RF-3 is a single-seat motor glider designed by René Fournier and first flown in 1960.

Design and development

Fournier produced the Volkswagen-powered RF-1 single-seat motor-glider with a high-aspect ratio low-mounted wing, registered F-WJGX it first flew on 6 July 1960. Fournier followed it with an improved variant, the RF-2 using a Rectimo AR.1200 engine, the first of two-built, with the help of Centre Est, first flew in June 1962. 

Fournier started a company Societé Alpavia to manufacture a production variant of the RF-2, named the RF-3. The first RF-3 was exhibited at the June 1963 Paris Air Show. Series production commenced later that year. 

An aerobatic variant with a strengthened airframe was produced as the Fournier RF 4.

Variants
RF-1
Prototype Avions Planeur first flown in 1960, one built.
RF-2
Improved variant, first flown in 1962, two built.
RF-3
Production variant first flown in 1963, 89 built by Alpavia at Gap-Tallard.

Specifications (RF-3)

References

External links

1960s French sailplanes
Fournier aircraft
Motor gliders
Single-engined tractor aircraft
Low-wing aircraft
Aircraft first flown in 1963
Anthony Best. Anthony Best (born June 1937) is a British businessman and engineer who founded AB Dynamics, and most recently served as its Chairman until 2021.

Biography 
Best studied Mechanical Sciences Tripos (Engineering) at Jesus College, Cambridge, graduating in 1960, upgraded to an MA in 1964. After a spell as a Production Manager at Avon Rubber, in 1967 Best joined Alex Moulton at Moulton Developments as Chief Engineer working on vehicle suspensions for cars, trucks and coaches, before founding Anthony Best Dynamics Limited in 1982.

He was awarded the Institution of Mechanical Engineers' Thomas Hawksley Medal and the Automobile Division's Crompton Lanchester Medal in 1979. He is a Fellow of the Royal Academy of Engineering, a Fellow of the Institution of Mechanical Engineers and is on the Court of the Worshipful Company of Engineers.

References

1937 births
Living people
Alumni of Jesus College, Cambridge
Fellows of the Institution of Mechanical Engineers
Fellows of the Royal Academy of Engineering
Cherokee (rocket). The Cherokee was an experimental rocket built by the Cook Electric Co. for use by the United States Air Force during the 1950s for the testing of ejection seats.

History
Made from aluminum, Cherokee was a blocky, simple design that was designed for air-launch from a B-29 bomber. It was operated as part of Project Whoosh, an effort to determine if the use of ejection seats at supersonic speeds was feasible.

Launched from the B-29 mothership at an altitude of  it would fire a solid-fueled rocket to accelerate to supersonic speed, at which point the ejection seat, containing an anesthetized chimpanzee as a test subject, would be fired. The first test took place on January 26, 1954, at Edwards Air Force Base; another test in June was held before the project moved to Holloman Air Force Base, with two further tests being carried out in July 1955 and April 1956. None of the four chimpanzees used in the tests survived due to difficulties with the ejection system, however the project was considered a partial success.

References
Citations

Bibliography

 Burgess, Colin, and Chris Dubbs. Animals in Space: From Research Rockets to the Space Shuttle. 2006. New York: Springer Publishing. .
 Bushnell, David. History of Research in Space Biology and Biodynamics at the U.S. Air Force Missile Development Center, Holloman Air Force Base, New Mexico: 1946-1958 . Historical Division, Office of Information Services, Air Force Missile Development Center, Air Research and Development Command, Holloman Air Force Base, New Mexico. 1958. Accessed 2014-05-17. .

Experimental rockets of the United States
Equipment of the United States Air Force
Ejection seats
Boeing B-29 Superfortress
Animal testing in the United States
USA-251. USA-251, also known as GPS IIF-6, GPS SVN-67 and NAVSTAR 70, is an American navigation satellite which forms part of the Global Positioning System. It was the sixth of twelve Block IIF satellites to be launched.

Launch 
Built by Boeing and launched by United Launch Alliance, USA-251 was launched at 00:03 UTC on 17 May 2014, atop a Delta IV carrier rocket, flight number D366, flying in the Medium+(4,2) configuration. The launch took place from Space Launch Complex 37B at the Cape Canaveral Air Force Station, and placed USA-251 directly into medium Earth orbit.

Orbit 
As of 17 May 2014, USA-251 was in an orbit with a perigee of , an apogee of , a period of 729.22 minutes, and 55.04 degrees of inclination to the equator. It is used to broadcast the PRN 06 signal, and operates in slot 6 of plane D of the GPS constellation. The satellite has a design life of 15 years and a mass of .
 It is currently in service following commissioning on June 10, 2014.

References 

Spacecraft launched in 2014
GPS satellites
USA satellites
Spacecraft launched by Delta IV rockets
Lobber. The Lobber was a surface-to-surface cargo missile developed during the mid 1950s by Convair for use by the United States Army. Intended to deliver supplies to troops in combat, it was successfully tested, but failed to go into production.

History
Inspired by the use of artillery shells to resupply surrounded troops during the Battle of the Bulge, a contract for the development of a cargo missile was awarded to Convair in 1958 by the U.S. Army. Developed by a team led by Bill Chana, the missile was capable of delivering  of cargo over a distance of approximately ; once the rocket motor burned out, a parachute was deployed to deliver the cargo.  A portable, mortar-like launcher was used; it allowed for a three-man team to transport and fire the missile; Lobber was described as being able to reliably hit a target "within the length of a football field" and was expected to cost less than $1,000 USD per round. It was proposed that modular cargo sections be pre-packaged with supplies, with nose and tail sections attached to the needed section just before launch.

The first test launch took place in December 1958 at Camp Irwin in California. Flight testing proved highly successful, and Convair proposed variants with explosive, chemical, and nuclear warheads; the United States Marine Corps also considered adopting the missile, and it was also proposed to develop a variant for anti-submarine warfare usage by the United States Navy. Larger variants were also proposed, as well as civilian usage for firefighting. However the inherent inaccuracy of the unguided, solid-fueled rocket, combined with logistical issues, meant that Lobber was not adopted for service.

References
Citations

Bibliography

External links

Rocket weapons of the United States
United States Army equipment
Annemie. The Annemie is a windmill located on the Boschdijk 1006 in Eindhoven, in the province of North Brabant, Netherlands. Built in 1891 on an artificial hill, the windmill functioned as a gristmill. The mill was built as a tower mill and its sails have a span of . The mill is a national monument (nr 14637) since 15 August 1972.

History
The Annemie was built in 1891 by Antonius van Himbergen from Bladel, who also built De Roosdonck in Nuenen, which also used to function as a gristmill. In 1957, the mill was refurnished as a house, and the inner workings were removed, though main parts like the central axis and wheel were kept. In 1991, the mill was restored, and after consecutive maintenance works between 2005 and 2019, the mill is presently in reasonable condition. The Annemie is privately owned and used as living accommodations as well as an office, so visits are not possible.

Gallery

See also
Annemieke, a Dutch feminine given name

References

External links
Chris Kolman [et al.], Annemie in: Monumenten in Nederland - Noord-Brabant, Rijksdienst voor de Monumentenzorg/ Waanders Uitgevers, Zeist/Zwolle, 1997, p. 153

Windmills in North Brabant
Rijksmonuments in North Brabant
Buildings and structures in Eindhoven
Polyhexahydrotriazine. Polyhexahydrotriazines (PHTs) are polymers of hexahydro-1,3,5-triazines, a class of heterocyclic compounds with the formula (CH2NR)3. They are among the strongest known thermosetting plastics and are stable to solvents at pH > 3, but decompose to the monomers in acidic solutions.

Synthesis

Various PHTs have been synthesized at room temperature in one step in the early 2000s; they were considered impractical due to their poor mechanical properties. It was later elucidated that, due to the temperature of synthesis, the poor mechanical properties observed were likely due to poly(hemiaminal) formation and not PHT formation.

In 2014, Jeanette Garcia, Gavin Jones and a team of researchers at IBM Almaden Research Center, US, developed a new type of PHT (1.6) in what has been called a "happy accident". Garcia had left out a reagent when preparing her mix of chemicals. When low heat was applied to the beaker of paraformaldehyde and 4,4ʹ-oxydianiline, it had created a hemiaminal dynamic covalent network (HDCN). Heating the HDCN to 200 °C transformed it into two new polymers: PHT 1.6 and an organogel known as polyhemiaminal (PHA)

Properties
The PHT 1.6 has a yellowish color. It is resistant to solvents at pH > 3, but decomposes into monomers within a day in acidic solutions at pH < 2. This property is unusual for thermosetting plastics and allows easy recycling. This PHT has a Young's modulus exceeding 10 GPa, which is among the highest for a thermosetting plastic; it can be further increased by ~50% by dispersing carbon nanotubes in the polymer. The PHT is brittle, and cracks when strained to 1%. Upon heating, it softens at a glass transition temperature of ~190 °C and decomposes at ~300 °C.

Possible uses 
A number of industries could benefit from the use of PHT in manufacturing parts and devices due to its recyclability, lightweight structure, and strength:
 Aerospace - PHT used in the development of wings, tails, bodies, and rutters would provide a lightweight, durable vessel for both commercial and personal aircraft applications. PHT in combination with PHA could be used to adhere aircraft pieces that are exposed to harsh environmental conditions and high speeds.
 Automotive - When manufacturing automobiles, PHT would provide a light, high performance option for auto body parts such as panels, hoods, and exterior trim pieces.
 Semiconductors - Semiconductor chips and transistors made of PHT would allow for the reworking of defective electronics rather than having to discard the equipment.

References

Amines
Triazines
Organic polymers
Thermosetting plastics
Operation Desert. Operation Desert () was a German synthetic fuel project during World War II.  It attempted to build a shale oil industrial production complex for utilization of Swabian Alb oil shale deposits (Posidonia Shale).

The project was driven by the fuel needs of the German army at the last phase of World War II due to decreasing conventional petroleum supplies.  Three companies conducted pilot tests. LIAS-Ölschiefer-Forschungsgesellschaft mbH, established in September 1942, started tests in Frommern.  Kohle-Öl-Union von Busse KG, established on 30 July 1943 in Berlin, tested in-situ retorting on the outskirts of Schörzingen.  Deutsche Ölschiefer-Forschungsgesellschaft mbH, established on 20 September 1943 in Schömberg, became later the core of the Operation Desert.  Schutzstaffel (SS) and Hermann Göring personally became involved in the project in late 1943.  On 2 May 1944, SS established oil shale company Deutsche Schieferöl GmbH for its own shale oil plant near Erzingen.  Also IG Farben became involved in shale oil. In July 1944, Operation Desert became a part of the Geilenberg Programme.

For the Operation Desert construction of ten shale oil extraction plants in Württemberg and Hohenzollern were ordered by Edmund Geilenberg. Prisoners from seven nearby subcamps of the Natzweiler-Struthof concentration camp, established by the route of  Tübingen - Aulendorf and Nebenstrecke Balingen- Rottweil railway lines, were used as a workforce. The main contractor for building these plants was Deutsche Bergwerks- und Hüttenbau GmbH, a subsidiary of Reichswerke Hermann Göring. About 5,000 prisoners were used for construction works and more than 10,000 prisoners had been exploited for the oil-shale works.  When Soviet troops advanced into Estonia in 1944, about 200 oil shale specialists from Estonia, employees of Baltische Öl GmbH , an affiliate of IG Farben, were evacuated to Schömberg.

However, out of ten planned plants only four became operational. The technology was primitive carbonization and oil yield was low.  Mined oil shale was heaped into mounds which were ignited after covering by peat. Distilled shale oil and oil shale gas were collected through  perforated pipes. Oil was separated from gas by electric filters.  Until the end of the war, only 1,500 tonnes of shale oil was produced.

After the war French occupation forces tried continue the shale oil production operations but due to unprofitability it was halted in 1948.

References

Bibliography 

 
 
 
 

Oil shale in Germany
Petroleum economics
Economy of Nazi Germany
Germany in World War II
Zollernalbkreis
RIOT (operating system). RIOT is a small operating system for networked, memory-constrained systems with a focus on low-power wireless Internet of things (IoT) devices. It is open-source software, released under the GNU Lesser General Public License (LGPL).

Background
It was initially developed by Free University of Berlin (FU Berlin), French Institute for Research in Computer Science and Automation (INRIA) and the Hamburg University of Applied Sciences (HAW Hamburg). RIOT's kernel is mostly inherited from FireKernel, which was originally developed for sensor networks. In 2015, one of the co-developers, Matthias Wählisch was awarded the Young Scientist Award of the Forum for Excellent Young Scientists for the contributions of his team to the open source operating system RIOT. In 2016, the ED STIC Doctoral Prize 2017 of the University of Paris-Saclay was awarded to another co-founder, Oliver Hahm for his contribution to the project.

Technical aspects
RIOT is based on a microkernel architecture. In contrast to other operating systems with similarly low memory use (such as TinyOS or Contiki), RIOT allows application software programming with the programming languages C and C++, and Rust, also by an experimental application programming interface (API). It has full multithreading and real-time abilities. Secure Sockets Layer (SSL) and successor Transport Layer Security (TLS) are supported by popular libraries such as wolfSSL.

RIOT runs on processors of 8 bits (such as AVR Atmega), 16 bits (such as TI MSP430), and 32 bits (such as ARM Cortex). A native port also enables RIOT to run as a Linux or macOS process, enabling use of standard developing and debugging tools such as GNU Compiler Collection (GCC), GNU Debugger, Valgrind, Wireshark, etc. RIOT is partly Portable Operating System Interface (POSIX) compliant.

RIOT provides multiple network stacks, including IPv6, 6LoWPAN, or content centric networking and standard protocols such as RPL, User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and CoAP.

Source code
RIOT source code is available on GitHub, and developed by an international community of open source developers.

See also
 Contiki
 TinyOS
 FreeRTOS
 Nano-RK
 Zephyr
 Comparison of real-time operating systems

References

External links
 

ARM operating systems
Embedded operating systems
Free software operating systems
Internet of things
Microkernels
Microkernel-based operating systems
MIPS operating systems
Real-time operating systems
Rigging (material handling). Rigging is both a noun, the equipment, and verb, the action of designing and installing the equipment, in the preparation to move objects. A team of riggers design and install the lifting or rolling equipment needed to raise, roll, slide or lift objects such as  heavy machinery, structural components, building materials, or large-scale fixtures with a crane, hoist or block and tackle. 

Rigging comes from rig, to set up or prepare. Rigging is the equipment such as wire rope, turnbuckles, clevis, jacks used with cranes and other lifting equipment in material handling and structure relocation. Rigging systems commonly include shackles, master links and slings, and lifting bags in underwater lifting. 

In the United States the Occupational Safety and Health Administration (OSHA) regulates workplace safety including rigging in CFR 1926.251. The Health and Safety Executive is responsible for the matters in the United Kingdom.

Equipment

Winch

Procedures

Safety

Gallery

See also

References

External links
 3.5 minute video on some basic cable rigging safety
 OSHA 1926.251 Rigging equipment for material handling
 what is rigging equipment

Material-handling equipment
Lifting equipment
Sodium cyanate. Sodium cyanate is the inorganic compound with the formula NaOCN.  A white solid, it is the sodium salt of the cyanate anion.

Structure
The anion is described by two resonance structures:

The salt adopts a body centered rhombohedral crystal lattice structure (trigonal crystal system) at room temperature.

Preparation
Sodium cyanate is prepared industrially by the reaction of urea with sodium carbonate at elevated temperature.
2OC(NH2)2 + Na2CO3 → 2Na(NCO) + CO2 + 2NH3 + H2O
Sodium allophanate is observed as an intermediate: 

It can also be prepared in the laboratory by oxidation of a cyanide in aqueous solution by a mild oxidizing agent such as lead oxide.

Uses and reactions
The main use of sodium cyanate is for steel hardening.

Sodium cyanate is used to produce cyanic acid, often in situ:

This approach is exploited for condensation with amines to give unsymmetrical ureas:

Such urea derivatives have a range of biological activity.

See also
 Cyanate

References

Cyanates
Sodium compounds
Bruce Woodgate. Bruce E. Woodgate (1939 – April 28, 2014) was a British-born American aerospace engineer, inventor and astronomer, who worked at NASA's Goddard Space Flight Center for forty years. He was the principal investigator of the Space Telescope Imaging Spectrograph (STIS), a spectrograph and camera which was installed on the Hubble Space Telescope in 1997. Woodgate oversaw the design, development and construction of the STIS. Astronomers and other scientists have used the STIS to study and measure a wide range of light wavelengths in deep space.  Woodgate's invention has been called a "game changer" in the field of astronomy, allowing scientists to discover an "invisible high-speed collision" near SN 1987A, as well as new planets and black holes. A power failure knocked STIS offline in 2004, but it was repaired in 2009.

Aside his from his work as the principal investigator on STIS, Woodgate had also begun development on a new UV detector which counts protons utilizing new nano-fabrication technologies. He was active in several new technologies such as photon-counting electron multiplying CCDs and integral field spectrographs designed for the direct detection of habitable exoplanets.  He was honored with the NASA Distinguished Service Medal and the Award of Merit from the Goddard Space Flight Center.  In addition to Goddard research, he was an avid sailor and an instructor in the Goddard Sailing Association.

Woodgate was born and raised in Eastbourne, East Sussex, England. He lived in a home on St. Anthony's Avenue in Eastbourne as a child and attended Eastbourne Grammar School. He began his career in astronomy and engineering at the Royal Greenwich Observatory, which was located at Herstmonceux Castle at the time. Woodgate then moved to London, where he earned a doctorate from University College London. 
He moved to the United States, where he held positions at Columbia University's Goddard Institute for Space Studies. In 1975, Woodgate joined the staff of NASA's Goddard Space Flight Center, where he worked for the rest of his career.

Bruce Woodgate died on April 28, 2014, from complications from a series of strokes suffered during the previous month. He was 75 years old.

References

1939 births
2014 deaths
NASA people
NASA astrophysicists
American aerospace engineers
British aerospace engineers
20th-century British  astronomers
21st-century American astronomers
Alumni of University College London
British emigrants to the United States
People from Eastbourne