omniomni/omni-engineering huggingface dataset:
Centrifugal clutch. A centrifugal clutch is an automatic clutch that uses centrifugal force to operate. The output shaft is disengaged at lower rotational speed and engages as the output increases to a certain speed. It is often used in mopeds, underbones, lawn mowers, go-karts, chainsaws, mini bikes, and some paramotors and boats to keep the engine from stalling when the output shaft is slowed or stopped abruptly, and to remove load when starting and idling. It has been superseded for automobile applications by the fluid coupling, torque converter and automated manual transmissions.

Operation

The input of the clutch is connected to the engine crankshaft while the output may drive a shaft, chain, or belt. As engine revolutions per minute increase, weighted arms in the clutch swing outward and force the clutch to engage. The most common types have friction pads or shoes radially mounted that engage the inside of the rim of a housing. On the center shaft, there is an assorted number of extension springs, which connect to a clutch shoe. When the central shaft spins fast enough, the springs extend, causing the clutch shoes to engage the friction face. It can be compared to a drum brake in reverse. This type can be found on most home-built karts, lawn and garden equipment, fuel-powered model cars, and low power chainsaws.

Another type used in racing karts has friction and clutch disks stacked together like a motorcycle clutch. The weighted arms force these disks together and engage the clutch.
When the engine reaches a certain speed, the clutch activates, working somewhat like a continuously variable transmission. As the load increases, the speed drops, disengaging the clutch, letting the speed rise again, and reengaging the clutch. If tuned properly, the clutch will tend to keep the speed at or near the torque peak of the engine. This results in a fair bit of waste heat, but over a broad range of speeds, it is much more useful than a direct drive in many applications.

History

Centrifugal clutches were used in railway locomotives before 1858, and referred to (in relation to electric motors) in a patent of 1899.

A patent was issued in the United States for an automotive centrifugal clutch (on an electric vehicle) in 1898. 

There is a design for a toy 'automatic clutch' in Meccano Magazine of June 1934.

Armstrong Siddeley cars featured automatic (centrifugal) clutches beginning in 1936.

Thomas Fogarty, who is also credited with inventing the balloon catheter, is credited with inventing a centrifugal clutch for small motor applications in the 1940s.

Principle 
This works on the principle of centrifugal force, which means when engine speed reaches a specific rpm (Revolutions per minute) it generates enough centrifugal force inside the clutch which results in clutch engagement, and it transmits the engine power. At lower speeds, it disconnects itself to stop power transmission.

See also
Saxomat

References

External links
Centrifugal Clutch Design | in 2021 by Automobile Informer
Compliant Centrifugal Clutches: Design, Analysis, and Testing, Master's thesis at the Harold B. Lee Library, Brigham Young University

Clutches
Misagh-2. The Misagh-2 (Also known as Mithaq-2) is an Iranian man-portable infrared-guided surface-to-air missile. The Misagh-2 is the successor to the Misagh-1. Like its predecessor, the Misagh-2 is based on Chinese technology, and in particular is believed to be an Iranian copy of the Chinese QW-1M MANPADS.

It is roughly comparable to the Soviet SA-18 Grouse missiles.

History
Iran's defense minister launched the domestic mass production of the Misagh-2 on 5 February 2006; it is manufactured at the Shahid Shah Abhady Industrial Complex.

Design
When fired, the Misagh-2 destroys its target within 5 second and has an operation temperature of -40 °C to +60 °C. The missile speed reaches 2.7+ Mach when it approaches its target.

The battery unit of the Misagh-2 is parallel to the launch tube, while the battery unit of the Misagh-1 is perpendicular. However, it is generally not possible to distinguish the Misagh-2 from the QW-1M, the QW-18, or the Misagh-3.

Operators 

 
 , Government of National Accord Affiliated Forces, probably supplied via Turkey.

Non-State Actors
 Houthis

References

Surface-to-air missiles of Iran
Post–Cold War weapons of Iran
Weapons and ammunition introduced in 2005
Guided missiles of Iran
Oghab. The Iranian Oghab (, meaning "Eagle") sometimes spelled as Akab and Okab missile is an unguided 230 mm (9 in) artillery rocket with a range of 34–45 km (20–28 mi). It is spin-stabilized in flight but has a proven circular error probable in excess of 500 m (1,500 ft), making it a highly inaccurate weapon. It carries a 70 kg (150 lb) high explosive fragmentation warhead, though it may also be able to carry chemical warheads. According to US sources, a modified version has been developed that could be carried and fired from Iranian Air Force F-14 Tomcat and F-4 Phantom II aircraft. The launcher is an elevatable triple-rail launcher assembly fitted to a Mercedes-Benz LA 911B 4×4 truck chassis.

History
The missile was developed from the Chinese Type-83 artillery rocket during the Iran–Iraq War, with the assistance of the People's Republic of China under an agreement signed in 1985. It entered service in 1986 and was immediately used in combat in an attack on the Iraqi city of Basra in December 1986. Around 260–270 Oghabs were reportedly fired during the war, though their effectiveness was limited. The missile's short range confined its use to attacks on Iraqi border cities and its lack of accuracy meant that Oghab attacks were far less effective than artillery barrages.

The Oghab was used by the Iranian Army and the Revolutionary Guards. It is known to have been exported to Hezbollah.

Variants
The Houthi al-Najm al-Thaqib (missile) also shows similarities to the oghab missile. It has not been seen since the Iran-Iraq War and is believed to be out of service.

References

Other sources
 Anthony H. Cordesman. Iran's Military Forces in Transition: Conventional Threats and Weapons of Mass Destruction, p. 296. Greenwood Publishing Group, 1999. 
 Anthony H. Cordesman, Martin Kleiber. Iran's Military Forces and Warfighting Capabilities, p. 60. Greenwood Publishing Group, 2007. 
 "Aerospace Industries Organization 230 mm OGHAB artillery rocket system (Iran)". Jane's Armour and Artillery, 2008.

External links
 "NTI: Country Overviews: Iran: Missile Capabilities". Nuclear Threat Initiative, February 2006.

Rocket artillery
Self-propelled artillery of Iran
230 mm artillery
Military equipment introduced in the 1980s
Kowsar. Kowsar () is a short-range, land-based anti-ship missile made by Iran. It can defeat electronic jamming systems and "cannot be thrown off course", according to Iranian officials.

The Kowsar designation apparently (Missile Defense Advocacy Alliance 2006) is used to refer to two different missiles: Iranian-produced versions of the PRC C-701 and the TL-10A.

Combat history
Some news reports indicate that this was the missile used on July 14, 2006 in the 2006 Lebanon War when Hezbollah fired two at Israeli warships.
One of the missiles hit the corvette INS Hanit, causing heavy damage and the deaths of four Israeli servicemen.  The other missile hit an Egyptian merchant ship causing heavy damage; it is reported that all the crew survived.

See also 
Military of Iran
Iranian military industry
Equipment of the Iranian Army

References 

Missile Defense Advocacy Alliance - "Iran acquires additional Chinese missile technology." Aviation Week & Space Technology. April 10, 2006.
Picture

Anti-ship missiles of Iran
Surface-to-surface missiles of Iran
Guided missiles of Iran
Military equipment introduced in the 2000s
Hydraulic bicycle. A hydraulic bicycle is a chainless bicycle that transfers power to the pedals by means of a liquid passing through tubes from hydraulic pump to hydraulic motor and back.

Advantages 
Advantages include:

 Shifting, through valves and displacement, provides either continuously variable gearing or more steps than traditional bicycles.
 Shifts smoothly under full power.
 Drive transmits power while pedaling forward and backward. Thus racers can power bicycle through turns by alternating short forward and backward pedal strokes. No slack or backlash occurs, in either direction. Ability to coast is maintained.
 Mechanism is clean and operates silently.
 Fewer moving parts (about 10 vs over 70), all of which are continuously bathed in clean lubricating fluid.
 Sealed systems require less maintenance than open chain system.
 Front-wheel drive and two-wheel drive systems can be implemented. (See two-wheel drive)
 Drive can double as a hydraulic brake, eliminating the weight, cost, and maintenance of regular brakes.
 The hydraulic (hydrostatic) transmission could be useful for recumbent bicycles because the hoses may be easier to route than a long chain.
 Energy recuperation, storage and power assist could be added.

Disadvantages 
Disadvantages include:
 Implementations to date are heavier than those of bicycle chain and sprocket designs.
 Though some of the components in a sealed hydraulic system maintain constant efficiency upwards of 95% in all conditions (see hydristor), the overall losses usually result in an efficiency of about 75% (power loss of about 25%, see hydraulic machinery). In contrast, a chain-and-sprocket system loses efficiency in bad weather and dirt – from 97% for clean new components down to less than 80% when worn and dirty.
 The system may leak fluid causing a mess and eventual failure.

References

External links 
 Cannondale Jacknife (Hydraulic Concept Bike)
 Engineering Students Compete To Redesign The Bicycle: hydraulic and pneumatic designs
 The Purdue Tracer: An Energy-Efficient Human-Powered Hydraulic Bicycle

Cycle types
Hexacene. Hexacene is an aromatic compound consisting of six linearly-fused benzene rings. It is a blue-green, air-stable solid with low solubility.

Hexacene is one of a series of linear polycyclic molecules created by such aromatic ring fusions, a series termed acenes; the previous in the series is pentacene (with five fused rings) and the next is heptacene (with seven). It and other acenes and their derivatives have been investigated in potential applications related to organic semiconductors.  Like larger acenes, hexacene is poorly soluble, but derivatives have been prepared with improved solubility, such as 6,15-Bis(tri-t-butylsilylethynyl)hexacene, which melts with decomposition at 96 °C.

Syntheses and structure
Hexacene has been the subject of many syntheses. One route uses thermal decarbonylation of a monoketone precursor.

Further reading
First synthesis: 
Marschalk, C. Linear hexacenes. Bull. Soc. Chim. Fr. 6, 1112–1121 (1939).

By dehydrogenation of hexacosahydrohexacene by palladium on carbon
Isolation: 
By decarbonylation of a diketone precursor:
Deoxygenation route:

External links
  Molecular graphics representation of the X-ray crystallographic structure determined for 6,15-bis(tri-t-butylsilylethynyl)hexacene—hexacene with bulky, protective substituents in the reactive 6- and 15- ring positions, see rotating graphic at base of page.
 Sander-Wise Polycyclic Aromatic Hydrocarbon Structure Index entry for hexacene, NIST Special Publication 922.

References

Organic semiconductors
Acenes
Polycyclic aromatic hydrocarbons
Hexacyclic compounds
Multi-service access node. A multi-service access node (MSAN), also known as a multi-service access gateway (MSAG), is a device typically installed in a telephone exchange (although sometimes in a roadside serving area interface cabinet) which connects customers' telephone lines to the core network, to provide telephone, ISDN, and broadband such as DSL all from a single platform.

Prior to the deployment of MSANs, telecom providers typically had a multitude of separate equipment including DSLAMs to provide the various types of services to customers. Integrating all services on a single node, which typically backhauls all data streams over IP or Asynchronous Transfer Mode can be more cost effective and may provide new services to customers more quickly than previously possible.

A typical outdoor MSAN cabinet consists of narrowband (POTS), broadband (xDSL) services, batteries with rectifiers, optical transmission unit and copper distribution frame.

See also
 IMS
 Next generation network
 Video-ready access device

References

Telephony equipment
Digital subscriber line
Boeing CC-137. The Boeing CC-137 is a retired transport and tanker aircraft which served with the Canadian Forces from 1970 to 1997. The Boeing 707-347C aircraft provided long range passenger transport for the military, VIP transport for government and air-to-air refueling for fighters such as the CF-116 Freedom Fighter and CF-18 Hornet. It was replaced by the Airbus CC-150 Polaris in the transport role and much later in the tanker role.

Design and development
During the 1960s, the Royal Canadian Air Force set out a requirement to replace the aging fleet of Canadair CC-106 Yukons and Canadair CC-109 Cosmopolitan transports. Initially, the Boeing KC-135 was being considered because the versatile design could also fulfill a yet-unspecified aerial refuelling role. Although a "purpose-built" aircraft would have suited the RCAF requirements better, an opportunity to acquire Boeing 707s as an alternative, soon presented itself.

Operational history

Canada purchased five Boeing 707s in 1970–71 to replace the RCAF's  CC-106 Yukons in the long range transport role and the CC-109 Cosmopolitan as an executive or short-range transport.  The first four aircraft had been built for Western Airlines, but that order was subsequently cancelled; the fifth was bought separately a year later. To fulfil Canada's requirements for aerial refueling, two aircraft were fitted with Beechcraft made probe and drogue refueling pods in 1972. The two sets of refuelling equipment were moved from aircraft to aircraft to keep fleet utilization even between the airframes.

The CC-137 fleet had a combined total of 191,154 hours, remaining in service in the transport role until 1995, with two aircraft continuing in use as tankers until 1997.

Most of the fleet ended up with the Northrop Grumman E-8 Joint STARS programme either for spare parts or conversion to E-8C standard for the United States Air Force.

Operators

Canadian Forces Air Command
No. 437 "Husky" Squadron RCAF based at CFB Trenton, Ontario

Specifications (CC-137)

See also

References

Notes

Bibliography

 Bowers, Peter M. Boeing Aircraft since 1916. London: Putnam, 1989. .
 Stachiw, Anthony L. Boeing CC137 (707-347C). St. Catharine's, Ontario, Canada: Vanwell Publishing Ltd., 2004. .

External links

 Canadian Forces Historical Aircraft – Boeing 707 (CC-137)
 Boeing CC-137 B707-320 at rcaf.com

CC-137
1970s United States military transport aircraft
Quadjets
Low-wing aircraft
Aircraft first flown in 1970
Aircraft with retractable tricycle landing gear
ALCO boxcab. The ALCO boxcabs were diesel-electric switcher locomotives, otherwise known as AGEIR boxcabs as a contraction of the names of the builders. Produced by a partnership of three companies, ALCO (American Locomotive Company) built the chassis and running gear, General Electric the generator, motors and controls, and Ingersoll Rand the diesel engine. The principle of operation was the same as modern locomotives, the diesel engine driving a main generator of 600 volts DC with four traction motors, one per axle.

There were three models, the 60-Ton with a six-cylinder four-stroke in-line engine of  of which twenty were produced, a 66-Ton of which six were produced, and the 100-Ton with two of the same engines of which seven were produced. A total of 33 units were produced between 1925 and 1928.

ALCO dropped out of the arrangement in 1928, acquired their own diesel engine manufacturer in McIntosh & Seymour and went on to start its own line of diesel switchers. The first ALCO boxcab switcher was outshopped in January 1931 and after a brief demonstration tour was sold to Jay Street Connecting. The ALCO Boxcab and two end cab switchers built in early 1931 used the McIntosh & Seymour 330 engine. This early development of end cab switchers led ALCO to build the HH series based on the McIntosh & Seymour 531 engine and using GE electrical components by mid-1931.

The five surviving examples of these earliest boxcabs can be found at the B&O Railroad Museum in Baltimore, MD (CNJ #1000 - the first), the National Museum of Transportation, St. Louis, MO (B&O #1/195/8000), the North Alabama Railroad Museum in Huntsville, Alabama (Union Carbide #3/11), the Illinois Railway Museum in Union, IL (DL&W #3001/IR #91), and the Henry Ford Museum in Dearborn, MI (IR #90).

The earliest boxcabs were often termed "oil-electrics" to avoid the use of the German name "Diesel", unpopular after World War I.

See also
GE boxcab, the continuation of this locomotive design after ALCO participation ceased.

References

External links
ALCo-GE-IR Boxcabs Page

Diesel–electric locomotives of the United States
ALCO locomotives
General Electric locomotives
Rolling stock innovations
Standard gauge locomotives of the United States
Shunting locomotives
Magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM) is an imaging technique that acquires magnetic resonance images (MRI) at nanometer scales, and possibly at atomic scales in the future. MRFM is potentially able to observe protein structures which cannot be seen using X-ray crystallography and protein nuclear magnetic resonance spectroscopy. Detection of the magnetic spin of a single electron has been demonstrated using this technique. The sensitivity of a current MRFM microscope is 10 billion times greater than a medical MRI used in hospitals.

Basic principle
The MRFM concept combines the ideas of magnetic resonance imaging (MRI) and atomic force microscopy (AFM). Conventional MRI employs an inductive coil as an antenna to sense resonant nuclear or electronic spins in a magnetic field gradient. MRFM uses a cantilever tipped with a ferromagnetic (iron cobalt) particle to directly detect a modulated spin gradient force between sample spins and the tip. The magnetic particle is characterized using the technique of cantilever magnetometry. As the ferromagnetic tip moves close to the sample, the atoms' nuclear spins become attracted to it and generate a small force on the cantilever. The spins are then repeatedly flipped, causing the cantilever to gently sway back and forth in a synchronous motion. That displacement is measured with an interferometer (laser beam) to create a series of 2-D images of the sample, which are combined to generate a 3-D image. The interferometer measures resonant frequency of the cantilever. Smaller ferromagnetic particles and softer cantilevers increase the signal-to-noise ratio. Unlike the inductive coil approach, MRFM sensitivity scales favorably as device and sample dimensions are reduced.

Because the signal-to-noise ratio is inversely proportional to the sample size, Brownian motion is the primary source of noise at the scale in which MRFM is useful. Accordingly, MRFM devices are cryogenically cooled. MRFM was specifically devised to determine the structure of proteins in situ.

Milestones
The basic principles of MRFM imaging and the theoretical possibility of this technology were first described in 1991. The first MRFM image was obtained in 1993 at the IBM Almaden Research Center with 1-μm vertical resolution and 5-μm lateral resolution using a bulk sample of the paramagnetic substance diphenylpicrylhydrazyl. The spatial resolution reached nanometer-scale in 2003. Detection of the magnetic spin of a single electron was achieved in 2004. In 2009 researchers at IBM and Stanford announced that they had achieved resolution of better than 10 nanometers, imaging tobacco mosaic virus particles on a nanometer-thick layer of adsorbed
hydrocarbons.

References

External links
University of Washington Quantum System Engineering and MRFM Home Page, https://web.archive.org/web/20060430032748/http://courses.washington.edu/goodall/MRFM/.
Magnetic-Resonance Force Microscopy, http://www.medgadget.com/archives/2005/04/magneticresonan.html.

Review Article: M. Poggio and C. L. Degen, Nanotechnology 21, 342001 (2010), 

Scanning probe microscopy
Nuclear magnetic resonance
Protein structure
Barbicide. Barbicide is a disinfectant solution used by barbers and cosmetologists for disinfecting grooming tools such as combs and hair-cutting shears. Manufactured by King Research, it was invented in 1947 by Maurice King and marketed heavily around the United States by his brother James.

Barbicide is a United States Environmental Protection Agency–approved combination germicide, pseudomonacide, fungicide, and a viricide effective against HIV-1, hepatitis B, and hepatitis C. Its active ingredient is alkyl dimethyl benzyl ammonium chloride (5.12% by volume); sodium nitrite and blue dye are also present.

Barbicide is sold as a concentrate diluted for use in a ratio of  of Barbicide concentrate mixed into  of water, with each stylist having a container for treating their own tools.

At one time, several U.S. states legally required barber shops to use Barbicide and according to the maker, two states continued to in 1997. A jar of Barbicide sits on display in the Smithsonian Institution's National Museum of American History.

References

External links
King Research
Barbicide Material Safety Data Sheet
Official Barbicide Europe Website

Disinfectants
Hairdressing
Products introduced in 1947
Luca Cardelli. Luca Andrea Cardelli  is an Italian computer scientist who is a research professor at the University of Oxford, UK. Cardelli is well known for his research in type theory and operational semantics. Among other contributions, in programming languages, he helped design the language Modula-3, implemented the first compiler for the (non-pure) functional language ML, defined the concept of typeful programming, and helped develop the experimental language Polyphonic C#.

Education
He was born in Montecatini Terme, Italy. He attended the University of Pisa before receiving his PhD from the University of Edinburgh in 1982 for research supervised by Gordon Plotkin.

Career and research
Before joining the University of Oxford in 2014, and Microsoft Research in Cambridge, UK in 1997, he worked for Bell Labs and Digital Equipment Corporation, and contributed to Unix software including vismon.

Awards and honours
In 2004 he was inducted as a Fellow of the Association for Computing Machinery. He was elected a Fellow of the Royal Society (FRS) in 2005. In 2007, Cardelli was awarded the Senior AITO Dahl–Nygaard Prize named for Ole-Johan Dahl and Kristen Nygaard.

Trivia

Cardelli created and published the Dijkstra font, a computer typeface mimicking Edsger W. Dijkstra's handwriting, in the late 1980s while working at DEC.

References

Alumni of the University of Edinburgh
Italian computer scientists
Year of birth missing (living people)
Living people
2004 fellows of the Association for Computing Machinery
Programming language researchers
Fellows of the Royal Society
DNA nanotechnology people
Dahl–Nygaard Prize
People from Montecatini Terme