omniomni/omni-engineering huggingface dataset:
Wig wag (washing machines). The wig-wag is the common name for the unusual solenoid mechanism used in belt-drive washing machines made by Whirlpool, Kenmore (manufactured by Whirlpool) and others, from approximately 1950 to 1987 in the United States. It was used in belt-drive Brastemp and Consul models built in Brazil from 1959 to 1990. 

They were common in US-style top-loading vertical-axis machines, not used in European front-loading horizontal-axis machines. Horizontal-axis machines rotate the drum to both agitate the clothes during washing and to spin them dry. A multi-speed motor is used instead of clutches.

Operation

A vertical-axis washing machine has two mechanisms: a central agitator for washing and a drum for spinning, both driven by the same motor and controlled independently by clutches to the belt drive.

The wig-wag is mounted atop the washing machine's transmission, where it oscillates back and forth like a railroad signaling wigwag (hence the name). When either solenoid is engaged, a rod catches and engages the transmission in the desired mode. A wig-wag is a form of servomechanism; the coils are not powerful enough to engage the belt clutch themselves, but they can move their pins within the cam bar, then the mechanical oscillation of the wig-wag provides the force to push the cam bar and engage the belt clutch. When a solenoid is de-energized, the pin drops due to gravity.

One of the wig-wag's solenoids is turned on to engage agitation during wash mode; the other solenoid is turned on to engage the spin-dry mode. The motor must be turned on before the solenoids are powered. Only one solenoid may be operated at a time. When neither solenoid is engaged, the transmission is in neutral, and only the pump is operating to drain water out of the tub.

During a normal cycle, most Whirlpool-built wig-wag equipped washers will fill, start the motor, then engage the wash solenoid. Upon completion of the wash mode, the wash (agitate) solenoid will be turned off, which will allow the pump to drain the tub. After a minute or two, the timer will then engage the spin wig-wag which will cause the rotation of the tub. This is in contrast to some other top-load washing machines, which start spinning and draining simultaneously. There are no pauses between cycles in these machines.

Problems with the wig-wag mechanism
There are three failures with the wig-wag mechanism. The first is that a solenoid tends to jam, often due to corrosion from operating in a damp environment or grease/dirt getting into the solenoid and preventing gravity from making the pin drop. The second common failure is peculiar to the wig-wag: since the wires that operate the solenoids are constantly being flexed by the motion of the wig-wag, they tend to break, causing the wash or spin cycle not to engage. The third typical failure is a short inside a solenoid's coil, which will eventually burn out the coil itself and create a discontinuity within it.

References

Electromagnetic coils
Laundry washing equipment
Actuators
HESA Shafaq. The HESA Shafaq or Shafagh (, "Twilight" or "Aurora") is an Iranian subsonic stealth aircraft project being developed by the Iran Aircraft Manufacturing Industrial Company (HESA).

Development
According to reports, the Shafaq will be a subsonic aircraft, but this might be changed. Additionally, Iranian officials have reported that the Shafaq will have a skin of radar-absorbing material.

This two-seat advanced training and attack aircraft appears to be based on the Russian-Iranian "Project Integral" and is fitted with Russian ejection seats. Reportedly, there are plans to produce three versions—a two-seat trainer/light strike version and two one-seat fighter-bomber versions. 

The Shafaq is designed by the Aviation University Complex (AUC), part of the Malek-Ashtar University of Technology (MUT). At the start of the program, Iran received help from Russia and the aircraft was known as Integral. Russia later backed away from this project for several reasons and Iran carried on the project by itself renaming it Shafaq. The Shafaq is designed as a sub-sonic aircraft, and made of radar-absorbing material. It has a large leading edge root extension (LERX) and a root aft of the wing which gives it an unusual circular sub-section.

A 1/7 scale model of the Shafaq has already completed testing in the AUC's wind tunnel and pictures have already been revealed which show that a full-scale model has already been built. The Shafaq will be built in different configurations including a two-seater trainer, a two-seater light Attack and a one-seater light attack variants. Roll-out of the first prototype was scheduled for 2008. The Shafaq's advanced cockpit features color MFDs and a Russian-made K-36D ejection seat.

According to AIO (Aerospace Industries Organisation), the aircraft was expected to be flight tested during 2017, and featuring twin, outwardly canted vertical fins. This type of a tail design has become a favoured aerodynamic feature of Iranian designers that dates back to the development of the reverse-engineered Iranian version of the Northrop F-5, the HESA Saeqeh.

Specifications

See also

References

External links

 GlobalSecurity.org: Shafaq (Before Dawn)
 ainonline.com: Iran struggles to field a fighter 
 aeronautics.ru: aka "Vityaz-2000": a Russian based JSF

Stealth aircraft
Proposed aircraft of Iran
Shafaq
Single-engined jet aircraft
Mid-wing aircraft
Aircraft with retractable tricycle landing gear
Iron catastrophe. The iron catastrophe is a postulated major geological event early in the history of Earth, where heavy metals such as iron and nickel congregated in the core during a geologically brief period.

The original accretion of the Earth's material into a spherical mass is thought to have resulted in a relatively uniform composition.  While residual heat from the collision of the material that formed the Earth was significant, heating from radioactive materials in this mass gradually increased the temperature until a critical condition was reached. As material became molten enough to allow movement, the denser iron and nickel, previously evenly distributed throughout the mass, began to migrate to the center of the planet to form the core. The gravitational potential energy released by the sinking of the dense NiFe globules, along with any cooler, denser solid material, is thought to have been a runaway process, increasing the temperature of the protoplanet above the melting point of most components, resulting in the rapid formation of a molten iron core covered by a deep global silicate magma. This event, an important process of planetary differentiation, occurred at about 500 million years into the formation of the planet.

Formation of Earth's magnetosphere
This large spinning mass of super-hot metal is responsible for the creation of the Earth's magnetic field, the magnetosphere, which protects the Earth from solar wind and the most harmful components of solar radiation coming from the Sun. The magnetosphere protects both Earth's atmosphere and life to the present day and distinguishes the planet from its close celestial neighbour, Mars, which no longer has a significant magnetic field nor comparable atmosphere.  The term catastrophe is, here, in the mathematical sense of "a large, sudden change or discontinuity", as contrasted with "a disaster", because this event was necessary for life to emerge and evolve on Earth: without it, Earth's atmosphere would have been, as on Mars, stripped away by solar wind long before the present epoch.

Another theory, however, suggests Mars did once experience its own iron catastrophe and was once shielded by a magnetosphere.  By this theory Mars has simply cooled faster than the Earth, gradually solidifying its dynamic iron center, hence shutting down its magnetosphere. The finding of signs of liquid water once existing on Mars suggests that it once had its own magnetic shield to keep the water in the atmosphere of the planet from being blown into space by solar wind.

See also
Rain-out model

References

External links
Lecture // Columbia university, GEOLOGY V1001x

Planetary science
Geological processes
Hadean
André Coyne. André Coyne (10 February 1891 – 21 July 1960) was a French civil engineer who founded the consulting firm Coyne et Bellier and was President of the International Commission on Large Dams from 1945 to 1953. He designed 70 dams in 14 countries during his lifetime.

Biography 
Coyne was born in Paris on 11 February 1891. He received his education at École Polytechnique and its School of Civil Engineering afterwards.

He worked on the Plougastel Bridge and in 1928 was appointed as the chief engineer of dams in the Upper Dordogne River. While in that position, he designed the Marèges Dam which incorporated several innovative advancements in dam design (a.o., a spillway of the ski jumping ramp type). In 1935 he became the head of France's Large Dam Engineering Department and between 1945 and 1953 he served as President of the International Commission on Large Dams. In 1947 he departed civil service and started his own consulting firm, Coyne et Bellier.

Other dams he later designed in France include the Grandval and Roselend Dams. Abroad he designed the Kariba Dam on the Zimbabwe-Zambia border, the Daniel-Johnson Dam in Quebec and the Santa Luzia Dam in Portugal.

Coyne also designed the Malpasset Dam in Southern France.  Nearly immediately after construction was completed on the dam, cracks were noticed at the base.  A few years later, on 2 December 1959, the dam abruptly broke and collapsed, releasing a  wall of water that reached the nearby town of Fréjus, killing 423 people. It was said that Coyne was deeply affected by the dam's failure, and immediately blamed himself, claiming he was solely responsible. Indeed, Coyne did not implement the advice of Georges Corroy, a geologist, to build the dam 650 ft upstream, nor did he adapt the spillway gate to the flood flow. He died half a year later.

A study later found that the design of the dam was probably not the reason for its failure. Other factors were blamed instead, including the location of the dam, the stability of the rock material, the fact that a geological fault was found on the site, and heavy rain that had raised the water level by 15 feet that year. Also, intense mining for a new highway nearby downstream is suspected to have weakened the dam site.

Coyne died in Neuilly-sur-Seine on 21 July 1960.

References

External links
 Dam Failures Case Study: Malpasset Dam (France, 1959)
 Cracking Dams report on Malpasset Dam break
 Coyne et Bellier Official website
 Biography of André Coyne at Structurae

French civil engineers
École Polytechnique alumni
École des Ponts ParisTech alumni
Corps des ponts
1891 births
1960 deaths
Gunning transceiver logic. Gunning transceiver logic (GTL) is a type of logic signaling used to drive electronic backplane buses. It has a voltage swing between 0.4 volts and 1.2 volts — much lower than that used in TTL and CMOS logic — and symmetrical parallel resistive termination. The maximum signaling frequency is specified to be 100 MHz, although some applications use higher frequencies. GTL is defined by JEDEC standard JESD 8-3 (1993) and was invented by William Gunning while working for Xerox at the Palo Alto Research Center.

All Intel front-side buses use GTL. As of 2008, GTL in these FSBs has a maximum frequency of 1.6 GHz. The front-side bus of the Intel Pentium Pro, Pentium II and Pentium III microprocessors uses GTL+ (or GTLP) developed by Fairchild Semiconductor, an upgraded version of GTL which has defined slew rates and higher voltage levels. AGTL+ stands for either assisted Gunning transceiver logic or advanced Gunning transceiver logic. These are GTL signaling derivatives used by Intel microprocessors.

References 

Computer buses
JEDEC standards
Logic families
Broach. Broach may refer to:

 Broaching (metalworking), a machining operation that uses a metalworking tool with a series of chisel points mounted on one piece of steel
 Broach (nautical), a sudden loss of control of a vessel caused either by wind action or wave action
 BROACH warhead, an advanced multi-stage warhead developed by a consortium of British companies
 Broach spire, a spire that starts on a square base and is carried up to a tapering octagonal spire by means of triangular faces
 Barbed broach, a dental instrument

People 
 Chris Broach (born 1976), American musician in the band Braid
 Elise Broach (born 1963), American author

See also 
 Brooch, a decorative item designed to be attached to garments 
 Bharuch, also known as "Broach", a city and district in south Gujarat state in India
Security association. A security association (SA) is the establishment of shared security attributes between two network entities to support secure communication. An SA may include attributes such as: cryptographic algorithm and mode; traffic encryption key; and parameters for the network data to be passed over the connection. The framework for establishing security associations is provided by the Internet Security Association and Key Management Protocol (ISAKMP).  Protocols such as Internet Key Exchange (IKE) and Kerberized Internet Negotiation of Keys (KINK) provide authenticated keying material.

An SA is a simplex (one-way channel) and logical connection which endorses and provides a secure data connection between the network devices. The fundamental requirement of an SA arrives when the two entities communicate over more than one channel. Take, for example, a mobile subscriber and a base station. The subscriber may subscribe itself to more than one service. Therefore, each service may have different service primitives, such as a data encryption algorithm, public key, or initialization vector. To make things easier, all of this security information is grouped logically, and the logical group itself is a Security Association. Each SA has its own ID called SAID. So both the base station and mobile subscriber will share the SAID, and they will derive all the security parameters. 

In other words, an SA is a logical group of security parameters that enable the sharing of information to another entity.

See also
IPsec
Virtual private network (VPN)

Notes

References
Internet Key Exchange (IKEv2) Protocol - RFC 5996

IPsec
Cryptography
Servowriter. A servowriter or disk writer is a complex machine used in the manufacturing of a hard disk drive. It can write servo tracks (a circular string of sector marks) with much greater precision than a disk drive can.  This is due to the big motors, sensors and cooling systems that would be too bulky and expensive to build into a disk drive.  The servowriter writes the tracks on the raw media in the factory before the media is assembled into the disk drive.  The assembled disk drive can follow the precise tracks, even though it is not capable of writing them.  Once the read/write head has found the proper track, it can read and write data between the sector marks on the track.

A servowriter is used to write servo tracks on the disk platters which make up part of the servomechanism that positions the actuator arm. 

A servowriter can be split in three major parts:
 An accurate spindle that will set a perfect speed to help the head to fly on the surface and the right frequency to write the data.
 An actuator with precise positioning system to write the servo information on a perfect circle with a width of less than a micrometer.
 An electronic part that will write the servo information at the right frequency.
The head needs to fly on the electromagnetic surface of the disk to place the spin up or down. The gap in the magnet will read or write using the Laplace Force FL = idl^B

References 
 http://domino.research.ibm.com/tchjr/journalindex.nsf/600cc5649e2871db852568150060213c/dd9540e113670fb885256bfa0067f9e2!OpenDocument
 https://ieeexplore.ieee.org/document/5389662
 https://www2.hgst.com/hdd/library/whitepap/tech/servowrite.htm
 http://www.abrahamassociates.com/portfolio/servowriter_module.html
 http://www.abrahamassociates.com/portfolio/servowriter_positioner.html

Hard disk drives
Sprue (manufacturing). A sprue is a large diameter vertical channel through which liquid material is introduced into a mold. It connects the pouring basin to the runner. In many cases it controls the flow of material into the mold.  During casting or molding, the material in the sprue will solidify and need to be removed from the finished part. It is usually tapered downwards to minimize turbulence and formation of air bubbles.

Casting
In casting, a sprue is the passage through which a molten material is introduced into a mold, and the term also refers to the excess material which solidifies in the sprue passage.

Function
Sprues can serve as filters, as heat sinks, and as feeders. Bronze, in particular, has a high shrinkage rate as it is cooling. A sprue is tapered with its bigger end at the top to receive the liquid metal, the smaller end is connected to the runner.

Sprue design
The design of the sprue gating and runner is also essential for casting. The design can incorporate either bottom or vertical gating.

For bottom gating

where:

   = Time for filling

 = Area of mold

 =  Area of gate

   =  Acceleration due to gravity

  = Total height

 = Height of mold cavity

This equation may change if the height of gating is equal to height of casting material.

Then the equation will be:

or, simplified,

where:

   = Time for filling

 = Area of mold

 =  Area of gate

   =  Acceleration due to gravity

  = Total height (Height of gating + height of mold cavity)

 = Height of mold cavity

Injection molding

In injection molding, sprue refers to the passage through which a liquid material (such as polystyrene or polyvinyl chloride) flows into a die, where the material solidifies to form parts.  Sprue also refers to the material that solidifies in these passages, forming a framework that attaches the parts in a roughly planar arrangement.

Sprues, runners, and gates
Some moldmakers distinguish the sprue, the gate, and the runner. The sprue is a large-diameter channel through which plastic flows, usually around the edges of the part or along straight lines. The runner is a smaller channel from the sprue to the individual part. An analogy may be found in a water system that employs a water main (sprue) and smaller pipes (runners) to individual houses. The gate is the location at which the molten plastic enters the mold cavity and is often evidenced by a small nub or projection (the "gate mark") on the molded piece. 
 
Many scale-model kits are made from injection-molded plastic. Hobbyists typically remove the parts of a model kit from the runner using a sharp craft knife or razor saw. The sprues usually form a rectangle with the runners and parts inside which makes them easier to box.

Model makers sometimes use sprues or runners as raw material to fabricate additional parts, such as railings on model ships, antenna wires on airplanes, or greebles on fictional spacecraft.

Sprues in model kits often include engravings to identify the parts by number.

See also
Chvorinov's rule

References

Casting (manufacturing)
Plastics industry
Napier Gazelle. The Napier Gazelle is a turboshaft helicopter engine that was  manufactured by D. Napier & Son in the mid-1950s. In 1961 production was nominally transferred to a joint venture with Rolls-Royce called Napier Aero Engines Limited. But the venture closed two years later.

Variants
NGa.1Emergency rating  at 20,400 rpm, 1 hour rating  at 19,800 rpm, Max continuous rating  at 19,000 rpm
NGa.2Emergency rating  at 20,400 rpm
NGa.2(R)
NGa.2 series 2
NGa.3Emergency rating  at 20,400 rpm
NGa.4Emergency rating  at 20,400 rpm
NGa.13(R)
NGa.13 series 2
NGa.18
NGa.22
Mk.101
Mk.161
Mk.162 (NGa.13 series 2)
Mk.165
Gazelle 501
Gazelle 503
Gazelle 512
Gazelle 514
Gazelle E.219

Applications
These helicopter engines were used on the Westland Wessex HAS 1 and HAS 3 (other versions of the Wessex had two Rolls-Royce Gnome engines) and the Bristol Belvedere (later Westland Belvedere) transport helicopter.

Engines on display

A preserved Napier Gazelle is on display at the Royal Air Force Museum London.
A preserved Napier Gazelle from a Westland Wessex helicopter is on display at the Queensland Air Museum, Caloundra, Australia.
A Napier Gazelle is on display at the South Yorkshire Aircraft Museum, Doncaster
A further Napier Gazelle is displayed at the Solent Sky Museum, Southampton

Specifications (Gazelle 501 / Mk.101 / NGa.2(R))

See also

References

Notes

Bibliography

 Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989.

External links

Flight, July 1967, Napier Gazelle

Gazelle
1950s turboshaft engines
Windowing. Windowing may refer to:
Windowing system, a graphical user interface (GUI) which implements windows as a primary metaphor
In signal processing, the application of a window function to a signal
In computer networking, a flow control mechanism to manage the amount of transmitted data sent without receiving an acknowledgement (e.g. TCP windowing)
Date windowing, a method to interpret a two-digit year as a regular four-digit year, see Year 2000 problem
Address Windowing Extensions, a Microsoft Windows Application Programming Interface
A process used to produce images in a computed tomography (CT) scan
A method of publication wherein a work is published on different media at different times (e.g. first in cinemas, then on Blu-ray)

See also
Window (disambiguation)
Windows (disambiguation)
Thames Barrier Park. The Thames Barrier Park is a   park in Silvertown in the London Borough of Newham and is named after its location on the north side of the River Thames next to the Thames Barrier. It is intended to aid the regeneration of the area by creating an attractive public space alongside residential and commercial developments. It is adjacent to Pontoon Dock DLR station.

Allain Provost and Alain Cousseran of Groupe Signes with Patel Taylor won the international competition to design the park in 1995. As the first largely post-modern design in London, the park has a fresh modern look with adventurous planting and dancing water fountains.

The site was built on what was one of the country's most polluted sites, the former PRChemicals factory. Decontaminating the site took many years.

External links
Official site
Images of Thames Barrier Park

References

Urban public parks
Parks and open spaces in the London Borough of Newham
Tourist attractions in the London Borough of Newham
Ground propulsion. Ground propulsion is any mechanism for propelling solid bodies along the ground, usually for the purposes of transportation. The propulsion system often consists of a combination of an engine or motor, a gearbox and wheel and axles (or caterpillar tracks) in standard applications.

The primary and most natural type of propulsion is the use of muscle power. The invention of the wheel allowed for the development of vehicles like Carts and Wagons that make more efficient use of muscle power, allowing larger loads to be transported. Vehicles drawn by humans and domesticated animals are not economically as important as they once were, but they still exist. Examples of human-powered vehicles are rickshaws and cycle rickshaws.

The development of the steam engine and internal combustion engine allowed for the development of rail vehicles and motor vehicles, all of which have some form of a powertrain. The electric motor allowed for quieter vehicles with lower emissions, and frequently higher engine efficiency.

Some less commonly used or experimental engines are:
Turbines
Stirling engines
Fuel cells

Propulsion