omniomni/omni-engineering huggingface dataset:
Tara Labs. TARA (The Absolute Reference Audio) Labs is a manufacturer of high-end audio cables from Medford, Oregon. It is currently led by president Merrill Bergs. Tara Labs is known for their use of solid wire.

History 

TARA Labs was established in 1984. As in the mid-1970s and early 1980s, TARA Labs had experimented with solid core conductors of different diameters. It was hypothesized that an 'optimum diameter' of 18 AWG (American Wire Gage) or 1 millimeter was ideal for audio frequencies because there was minimal high-frequency attenuation caused by the principles known as the Skin Effect. Founders Matthew Bond's & Merrill Berg's work was corroborated by research work from the NBS or National Bureau of Standards in the 1930s and confirmed later by Stereophile in July 1988, in a table presented as the DC to AC resistance ratio versus frequency in wires of different diameters. TARA Labs is credited with the invention of solid-core wires for audio use because his work predates Dennis Morecroft (1984) and any of the early solid-core wires developed for use in audio in England at the time.

Their first commercial speaker cables were designed in 1984, the Phase II speaker cable, which was a solid core design. Later, in 1990, TARA Labs introduced the world’s first cable to have a floating conductor unterminated at one end that would allow for an increased high-frequency bandwidth to be coupled to the signal-carrying conductors (US patent No. 5033091). Later, a control device inside a box fitted to the cable (The Temporal Continuum) allowed the user to adjust the amount of high-frequency energy to be heard.

TARA Labs introduced Rectangular Solid Core cables in 1992. These cables employed solid core conductors with a rectangular cross-section and can be made in specific proportions (width and height). This affects the tuning of the frequency response of a conductor as compared to around a conductor of the same size or DC resistance.

The cables employed solid core conductors with a rectangular cross-section. Both the Gen2 conductor and the smaller Gen3 conductor are said to be Eight-Nines™ pure copper, which is 99.999999% pure. TARA Labs’ trademarks for this technology are 8N™ and SA-OF8N® (Super Annealed – Oxygen-Free 8 Nines copper). According to Bond, the term ‘annealing’ refers to the method whereby a conductor can be made softer and more conductive.

In 1999 TARA Labs introduced the "Zero" interconnect with a Vacuum Dielectric Insulation system.

In 2014, TARA Labs introduced a new line of high-end cables called The Evolution Series.

References

External links 
Tara Labs website
Stereophile Interview with TARA Labs, Dec. 1996

Audio equipment manufacturers of the United States
Companies based in Ashland, Oregon
1984 establishments in Oregon
Problems in coal mining. There are several types of problems in coal mining. These include safety, faults, the water table, washout, thin seams, and split seams. Significant mining engineering and other industrial engineering goes into helping coal mining operations to deal with these challenges.

Mine safety 

Gases underground present hazards of asphyxiation and ignition, depending on which gases are present in each part of the mine. Mine ventilation is one of the many capital costs of extending the mine. Mines without good safety culture were often lethal to the workers in centuries past, and although the per capita rates of injuries and deaths are lower in modern mining, they are still nonzero. Cave-ins are another significant risk. Even workers who survive the risks from gases and cave-ins face a risk of coal workers' pneumoconiosis. Personal protective equipment lessens this risk, but maintaining adequate protection is not easy, especially as advancing mining technologies have made mechanized fracturing of the rock and coal more efficient on a per-worker basis, making more dust to control in tighter spaces and time frames. Mining accidents are not only human tragedies but also financially expensive to mining companies, making their prevention a priority.

Faults 
If the coal seam reaches a fault, the seam may be significantly displaced, depending on the type of fault and its offset. Machinery trying to mine the coal may not be able to reach the displaced seam, if the displacement is too large. Coal mines use a combination of boreholes and high-resolution seismic reflection data to identify the larger faults and avoid the most faulted areas at the mine planning stage.

Water table

If the water table is too high, the mine will flood with water. While mining, water needs to be constantly pumped out and this is expensive.

Washout

If a distributary or river changes course and cuts into the swamp material that will form coal, the coal seam is not fully formed and there may be a problem with mining it.

Thickness of seams

If the seams are too thin it may be uneconomic to mine the coal. The cost of production could exceed the selling price.

Splitting of seams

If the seam splits, due to a delta collapsing, sand and silt sediments pile up on top until that area is covered. This may make all or part of the coal seam uneconomic to mine as it is too thin.

References 

Coal mining
Divinylbenzene. Divinylbenzene (DVB) is an organic compound with the chemical formula  and structure  (a benzene ring with two vinyl groups as substituents). It is related to styrene (vinylbenzene, ) by the addition of a second vinyl group.   It is a colorless liquid manufactured by the thermal dehydrogenation of isomeric diethylbenzenes.  Under synthesis conditions, o-divinylbenzene converts to naphthalene and thus is not a component of the usual mixtures of DVB.

Production and use
It is produced by dehydrogenation of diethylbenzene:
 C6H4(C2H5)2   →   C6H4(C2H3)2  +  2 H2
Divinylbenzene is usually encountered as a 2:1 mixture of m- and p-divinylbenzene, containing also the corresponding isomers of ethylvinylbenzene.

Styrene and divinylbenzene react to form the copolymer styrene-divinylbenzene, S-DVB or Sty-DVB. The resulting cross-linked polymer is mainly used for the production of ion exchange resin and Merrifield resins for peptide synthesis.

Nomenclature
 Ortho: variously known as 1,2-diethenylbenzene, 1,2-divinylbenzene, o-vinylstyrene, o-divinylbenzene
 Meta: known as 1,3-diethenylbenzene, 1,3-divinylbenzene, m-vinylstyrene, m-divinylbenzene
 Para: known as 1,4-diethenylbenzene, 1,4-divinylbenzene, p-vinylstyrene, p-divinylbenzene. 
These compounds are systematically called diethenylbenzene, although this nomenclature is rarely encountered.

References

Vinylbenzenes
Monomers
C4-Benzenes
Phenylene compounds
Flight test instrumentation. Flight test instrumentation (FTI) is monitoring and recording equipment fitted to aircraft for specific flight tests. The development program for a new aircraft design has a number of aircraft each of which has tasks to perform for development and certification tests. They are each fitted with FTI specific to their allotted tasks.

Different types of transducers are required to respond to particular physical quantities, such as air pressure on the wing surface or fuel pressure in a fuel tube, and which produce an electrical equivalent which is recorded by a data acquisition system.

A core component of a data acquisition system are the data acquisition units (DAU). These are electronic boxes that interface to FTI sources and are typically designed to be rugged and reliable. The current trend is to make these units as small as possible and move them closer to the sensors. This leads to many challenges for the designers of a data acquisition chassis such as how to cope with inhospitable environments and maintain functionality with smaller designs. For the end user it means shorter wiring, better accuracy and easier installation and maintenance.

So called commercial off-the-shelf (COTS) systems are commonly used to keep costs low and speed delivery. This approach, and indeed the use of FTI originally developed for aerospace applications well within the Earth’s atmosphere, is also increasingly common for space launchers and vehicles. More extensive testing and qualification is generally performed to help ensure reliability in the more hostile environments encountered at high altitudes and in space (for example ionizing radiation).

References

External links

Flight Test Instrumentation Engineering 1
Flight Test Instrumentation Engineering 2
Practical Aspects of Instrumentation System Installation

Aircraft components
2-(2-Ethoxyethoxy)ethanol. 2-(2-Ethoxyethoxy)ethanol, also known under many trade names, is the organic compound with the formula . It is a colorless liquid.  It is a popular solvent for commercial applications. It is produced by the ethoxylation of ethanol ().

Applications
It is a solvent for dyes, nitrocellulose, paints, inks, and resins. It is a component of wood stains for wood, for setting the twist and conditioning yarns and cloth, in textile printing, textile soaps, lacquers, penetration enhancer in cosmetics, drying varnishes and enamels, and brake fluids. It is used to determine the saponification values of oils and as a neutral solvent for mineral oil-soap and mineral oil-sulfated oil mixtures (giving fine dispersions in water).

It is also widely used as a solvent in a number of cosmetics and personal care products, including face cream, deodorant, makeup, hair dye, and sunless tanner.

See also
 Cellosolve
 2-Ethoxyethanol

References

Primary alcohols
Glycol ethers
Ethoxy compounds
Hazardous air pollutants
E44. E44, E-44 or E.44 may refer to:

Transportation 
 European route E44, a road part of the E-road network
 E 44 road (United Arab Emirates)
 PRR E44, an American electric road switcher locomotive built for the Pennsylvania Railroad
 Kushiro Sotokan Road and Nemuro Road, route E44 in Japan

Military 
 HMS E44, a World War I-era British E-class submarine
Evan Leigh. Evan Leigh (21 December 1810 – 2 February 1876) was an author, inventor, engineer and manufacturer of cotton spinning equipment. His invention of the twin screw for steam ships was patented in July 1849 and taken up both for mercantile and Royal Navy fleets.

Biography
He was born in Ashton-under-Lyne, Lancashire. 
He was the son of Peter Leigh, a cotton mill owner. Upon leaving school aged 16 he spent two years in Europe studying and observing engineering and science. When he returned home he took up employment in the family's cotton spinning mill. After about 25 years he retired from cotton spinning and took up the manufacture of cotton spinning machinery. He patented among other things the Self Stripping Engine, the Derby Doubler or Lap Machine and the Loose Boss Top Roller. Supplying machines worldwide from his Collyhurst Works in Miles Platting, Manchester after moving from Cotton Street, Ashton-under-Lyne.

In 1870 he published a pamphlet: "A plan for conveying railway trains across the Straights of Dover". In 1871 he published: "The Science of Modern Cotton Spinning".

Evan Leigh died at his home: Clarence House, Chorlton-on-Medlock after a bout of chronic bronchitis on Wednesday, 2 February 1876 aged 65.

A portrait of Evan Leigh is in the possession of the National Portrait Gallery in London.

Family
He married Anne Allen the daughter of James Allen in Prestbury, Cheshire on 28 September 1831; they went on to have eight surviving children, three boys and five girls. One of his children, Evan Arthur Leigh, also carried out a number of patents. Improvements in a Method and Mechanism for the Manufacture of Worsted Yarns is one of them. It can be assumed that Evan Arthur Leigh carried on the business of cotton spinning.

Works
He wrote a book, The science of modern cotton spinning : embracing mill architecture, machinery for cotton ginning, opening, scutching, preparing, and spinning, with all the latest improvements : also articles on steam and water power, shafting, gearing and American system of belting compared, generation and application of steam criticised and explained, boilers, boiler explosions, &c. ... As said in the title, it is mainly about cotton milling and production.

Notes

References
 <https://www.ancestry.com/genealogy/records/evan-leigh-24-1nvgyw1>

External links
 

 Evan Leigh family tree

1810 births
1876 deaths
English inventors
People from Ashton-under-Lyne
19th-century English businesspeople
Excitation temperature. In statistical mechanics, the excitation temperature () is defined for a population of particles via the Boltzmann factor. It satisfies 

where 
 is the number of particles in an upper (e.g. excited) state;
 is the statistical weight of those upper-state particles;
 is the number of particles in a lower (e.g. ground) state;
 is the statistical weight of those lower-state particles;
 is the exponential function;
 is the Boltzmann constant;
 is the difference in energy between the upper and lower states.

Thus the excitation temperature is the temperature at which we would expect to find a system with this ratio of level populations. However it has no actual physical meaning except when in local thermodynamic equilibrium. The excitation temperature can even be negative for a system with inverted levels (such as a maser).

In observations of the 21 cm line of hydrogen, the apparent value of the excitation temperature is often called the "spin temperature".

References

Temperature
Baldpate (oil platform). Baldpate is a  offshore compliant tower oil platform near the coast of Louisiana, owned and operated by Hess Corporation. It was the first freestanding compliant tower to be built following the Lena platform which was a guyed compliant tower.  It is the second tallest structure built in water after the Petronius (oil platform). The Baldpate Platform was designed and built by Hudson Engineering (now J. Ray McDermott Engineering) in Houston, Texas, and installed by Heerema Marine Contractors.

Compliant towers are designed to be more flexible than traditional fixed truss towers such as the Bullwinkle (oil platform). Baldpate in particular is designed to move up to 10 feet laterally during severe storm conditions.

The complaint tower section jacket section was fabricated by Aker Gulf Marine, weights a total of 28,900 tons, far below the original estimate of 50,000 tones. The platform was built in multiple sections which were assembled together later when the structure arrived at its final location.  The lower 107 m (351 ft) tall base section weights 8,700 tons, this section has a wider base 140 feet squared that reduces to 90 feet squared at its top. The main legs of the structure have a diameter of 12 feet at their widest with a steel thickness of 3.5 inches. At the corner of each side the structure is supported by steel piles which reach a depth of 430 feet. The upper 402 m (1320 ft) tall tower section weights 20,200 tons. This section has a length and width of 90 feet across which remains constant from the bottom to the top of the frame. The main legs in this section have a diameter of 10.67 feet with a steel thickness of 3.3 inches. The total combined height of the jacket/truss tower section of Baldpate is 1,671 feet, 1,647 feet of which is under water. The topside weights an additional 9,800 tons giving the structure a total weight of 38,700 tons.

See also
 List of tallest oil platforms
 List of tallest freestanding steel structures
 Offshore oil and gas in the US Gulf of Mexico

References

External links
 Diagram at Skyscraper.com
 HMC World Records

Oil platforms off the United States
Petroleum industry in the Gulf of Mexico
Energy infrastructure in Louisiana
Scimitar-class patrol vessel. The Scimitar class were a class of fast patrol boat formerly in service with the British Royal Navy.

The two vessels of this class were of a commercial design known as the Lifespan Patrol Vessel built by Halmatic (now BAE Systems Surface Ships), and formerly served in an inshore waterways anti-terrorist role in Northern Ireland. They were acquired for the Royal Navy in 2003 for service with the Gibraltar Squadron, releasing two  boats that had filled this role for service with the Cyprus Squadron.

With the decommissioning of the survey launch  in February 2018, the two Scimitar-class boats became the smallest commissioned vessels in the Royal Navy. The two vessels were returned to the U.K. from Gibraltar in 2020, having been replaced there by two Archer-class boats, but were reported as still operational in Portsmouth at the end of 2020. Both vessels were decommissioned in a joint ceremony at Portsmouth Naval Base on 30 March 2022.

Vessels in the class

See also

References

External links
 

 
Military boats
Patrol boat classes
Ship classes of the Royal Navy
Western Stone. The Western Stone is a monolithic ashlar (worked stone block) forming part of the lower level of the Western Wall in Jerusalem. This largest stone in the Western Wall is visible within the Western Wall Tunnel. It is one of the largest building blocks in the world.

Dimensions

Exposed face
The stone's exposed face can be freely measured and is  long and  high, but its width, or depth, is hidden within the wall.

Depth
In June 2006, Harry M. Jol, from the University of Wisconsin–Eau Claire, performed measurements with ground-penetrating radar (GPR) to determine the depth of the stone. The conclusion of his team was that its depth ranges from approximately . Prior estimates ranged up to 16.5m.

Weight
The calculated weight of the stone block is of 250–300 tonnes, based on Jol's measurement. Prior to the Jol's GPR measurement, the stone was estimated to weigh between 550 and 600 tonnes.

Pre-2006 estimates
A previous estimate of the stone's depth was , a multiple of the GPR measurement, and led to a calculated total weight of 567 tonnes.; Other pre-2006 sources circulated similar figures, namely 550 to 600 tonnes. The Western Wall Heritage Foundation (WWHF) website indicates, as of March 2020, an estimated depth of , with an estimated weight of "several hundred tons", thus moderating its former estimated weight of 517 tonnes (570 short tons);

Location
The stone is located in a section of the Western Wall (in the broader meaning of the term) north of Wilson's Arch, below ground level, and can be accessed through the Western Wall tunnels. It is part of the "Great Course", a name used by the WWHF for the tallest and longest course (layer of stones) of the Western Wall. Its stone blocks are of Herodian age, and the stones next to the Western Stone are, in sequence, , , and  long, respectively.

See also
 Herodian architecture
 Archaeology of Israel
 Stone of the Pregnant Woman

References

Archaeological artifacts
Western Wall
Tabernacle and Temples in Jerusalem
Stones
Prai River Bridge. Perai River Bridge is a dual-three lane cable stayed bridge that straddles the Perai River in Seberang Perai, Penang, Malaysia. It is part of the Butterworth Outer Ring Road (BORR).

Designed by Dar Al-Handasah Consultants, it won the IStructE Award for Transportation Structures and the prestigious Supreme Award in 2006. Constructed by Lingkaran Luar Butterworth (Penang) Sdn. Bhd. on a turnkey contract.

Project overview
The project was carried out by Turnkey contractor, Lingkaran Luar Butterworth (Penang) Sdn. Bhd. The main sub-contractors to the Turnkey contractor are Ballast Needam International (left halfway through the project), IJM Construction Sdn. Bhd. in joint venture with Zublin International (Malaysia) Sdn. Bhd. and consists of the following works: 
 Approach viaducts consisting of twenty-two  long precast concrete, post-tensioned, glued segmental spans constructed by the use of an overhead launching gantry.
 Two  high, reinforced concrete (grade 80 N/mm2) cable stay pylons, with each pylon accommodating 14 pairs of stay cables.
 A  glued segmental, cable stayed main span constructed by cantilever erection method.
 Three precast segmental exit/entry ramps constructed both by the use of an overhead launching gantry and, for some spans, a heavy duty falsework support system.
 The dual three lane approaches on either side of the main bridge are  wide, the width of the main bridge deck is  and the ramp structures are  wide.
 Other items in the IJM-Zublin JV contract are the supply and erection of parapets, application of anti-carbonation paint and superstructure electrical works.

See also
 Penang Second Bridge
 Penang Bridge

References

External links
 The Butterworth Outer Ring Road (BORR)
 IStructE Supreme Award for Engineering Excellence: Sungai Prai Bridge

Bridges completed in 2005
Cable-stayed bridges in Malaysia
Advanced Mobile Phone Service. Advanced Mobile Phone Service, Inc. was a subsidiary of AT&T prior to the Bell System Divestiture. Abbreviated AMPS, the company was created in 1978 to build and operate the new Advanced Mobile Phone System, also abbreviated AMPS. AMPS was developed by Bell Labs to replace older, severely limited radiophone services, such as IMTS. AMPS was one of the first modern cellular phone systems, which remained in operation until 2008.

Service started in Chicago on October 13, 1983, and in the Washington, D.C., area December 1983. After divestiture, AMPS was divided among the 7 newly created Regional Holding Companies, now known as RBOCs:
 NYNEX Mobile Communications
 Bell Atlantic Mobile Systems
 Ameritech Mobile Communications
 BellSouth Mobility
 PacTel Mobile Access
 Southwestern Bell Mobile Systems
 U S West NewVector

Evolution of Successor Companies
Through a series of mergers, acquisitions, and re-consolidation among the Baby Bells, these 7 original mobile operating companies are now split as such -
AT&T Mobility
Ameritech Mobile Communications
BellSouth Mobility
Southwestern Bell Mobile Systems
Verizon Wireless
Bell Atlantic Mobile Systems
NYNEX Mobile Communications
AirTouch
PacTel Mobile Access
U S WEST NewVector

PacTel Mobile Access and U S WEST NewVector are owned by Verizon Wireless due to its co-ownership by Vodafone. PacTel Mobile Access was spun off into AirTouch in 1994, and U S WEST NewVector was spun off and merged into AirTouch in 1997. AirTouch was then acquired by Vodafone in 1999. Bell Atlantic and Vodafone combined their wireless operations to form Verizon Wireless in 2000.

Ameritech's Chicago n/w was divested and sold to GTE Wireless in 1999 as a condition of the former's merger with SBC Communications. In 2000, Bell Atlantic bought GTE and changed its name to Verizon Communications; at that point, GTE Wireless became part of Verizon Wireless.

References
AT&T History

Bell System
Defunct mobile phone companies of the United States
Telecommunications companies established in 1978
Technology companies disestablished in 1984
Mid-deck tanker. A mid-deck oil tanker is a tanker design which includes an additional deck intended to limit spills if the tanker is damaged. The extra deck is placed at about the middle of the draft of the ship. This design is an alternative to the double-hull tanker design, and is superior in terms of spill volume.

Although double-hull design is superior in low energy casualties and prevents spillage in small casualties, in high energy casualties where both hulls are breached, oil can spill through the double-hull and into the sea. In grounding events of this type, a mid-deck design overcomes this by eliminating the double-bottom compartments that are void with air. Since the density of seawater is greater than that of oil, water comes into the tanks instead of oil escaping out, and rather than spilling, oil is vented upwards into overflow tanks. 

A variation on the mid-deck tanker is the Coulombi Egg Tanker, which was approved by IMO as an alternative to the double hull concept. The United States Coast Guard does not allow this design to enter US waters, effectively preventing it from being built, although it is superior to the double hull in high energy casualties.

References 
 .

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Ship types
Ship design