omniomni/omni-engineering huggingface dataset:
Gilbert tessellation. In applied mathematics, a Gilbert tessellation or random crack network is a mathematical model for the formation of mudcracks, needle-like crystals, and similar structures. It is named after Edgar Gilbert, who studied this model in 1967.

In Gilbert's model, cracks begin to form at a set of points randomly spread throughout the plane according to a Poisson distribution. Then, each crack spreads in two opposite directions along a line through the initiation point, with the slope of the line chosen uniformly at random. The cracks continue spreading at uniform speed until they reach another crack, at which point they stop, forming a T-junction. The result is a tessellation of the plane by irregular convex polygons.

A variant of the model that has also been studied restricts the orientations of the cracks to be axis-parallel, resulting in a random tessellation of the plane by rectangles.

 write that, in comparison to alternative models in which cracks may cross each other or in which cracks are formed one at a time rather than simultaneously, "most mudcrack patterns in nature topologically resemble" the Gilbert model.

References

Tessellation
Statistical models
Patterned grounds
Spatial processes
Diglycidyl ether. Diglycidyl ethers are chemical compounds used as a reactive diluents for epoxy resin. Other uses include treating textiles and stabilizing chlorinated organic compounds. Diglycidyl ether itself is extremely toxic, and can prove fatal or cause permanent damage if inhaled or consumed orally. As a class of compounds, there are a number of them available commercially with much lower toxicity profiles. One such example is epoxy resin itself Bisphenol A diglycidyl ether.

References

 Diglycidyl ether at www.chemicalbook.com.
 CDC - NIOSH Pocket Guide to Chemical Hazards

Glycidyl ethers
Symmetrical ethers
Reactive diluents
Claw tool. The claw tool (also known as the Hayward Claw Tool) is a forcible entry tool used by firefighters, made of steel, that has a hook on one end and a forked end on the other. The tool was a major component in the Fire Department of New York during the early 20th century. Over the last fifty years, the claw tool has lost prominence due to the advent of newer and more efficient forcible entry tools.

History
The exact origin of the claw tool, which later became the Halligan bar, is not well documented, but according to FDNY folklore, it was discovered by firefighters responding to a fire at a lower Manhattan bank. The fire was started to cover up a burglary, and during the investigation, firefighters found an unusual tool with a claw-like end that the burglars had used to break into the bank. The firefighters believed that if the tool was good enough to break into a bank, it was good enough for their use, so they labeled it the "claw tool" and reproduced it many times over. It became the primary forcible entry tool used by the FDNY and is thought to be the first tool designed solely for that purpose. FDNY Deputy Chief Hugh Halligan later incorporated the fork end of the claw tool into his design of the Halligan bar in 1948.

Design and use 
The original claw tool weighed 12 pounds and was approximately 36 inches in length. It was designed with a claw on one end and a tapered fork on the other end.

See also
Halligan bar
Kelly tool

References

Firefighter tools
Hand tools
Dimethyl phosphorochloridothioate. Dimethyl phosphorochloridothioate is a chemical compound used as an intermediate for insecticides, pesticides, and fungicides, as well as additives for oil and gasoline, plasticizers corrosion inhibitors; flame retardants and flotation agents. It is an irritant for skin, eyes, and mucous membranes.

References

Organophosphorohalidates
Dithiobiuret. Dithiobiuret is an organosulfur compound with the formula HN(C(S)NH2)2.  It is a colourless solid that is soluble in warm water and polar organic solvents.  It is a planar molecule with short C-S and C-N distances (1.69, 1.38 Å, resp.) indicative of multiple C-S and C-N bonding.

The compound can be viewed as the product from the condensation of two molecules of thiourea, but it is prepared by treatment of 2-cyanoguanidine with hydrogen sulfide.  The conversion proceeds via guanylthiourea:
NCNC(NH2)  +  H2S   →   HN(C(S)NH2)(C(NH)NH2)
HN(C(S)NH2)(C(NH)NH2)  +  H2S   →   HN(C(S)NH2)2

It is used as a plasticizer, a rubber accelerator, and as an intermediate in pesticide manufacturing. It is extremely toxic; exposure can result in respiratory failure.

See also
 Biuret

References

External links
 
 Dithiobiuret at www.chemicalbook.com.

Thioureas
Brown Aeronautical Company. Brown Aeronautical Company was an American aircraft manufacturer in the pioneering era of flight between 1900 and 1914.

Three young men from Baltimore founded Brown Aeronautical shortly after the Halethorpe Air Meet of 1910. The first aircraft built, the Brown Lord Baltimore, was destroyed in a fire in October 1910. The second, the Brown Lord Baltimore II, had its first flight promoted throughout the city. On 17 May 1911, the hydroplane was demonstrated near the Light Street Bridge in the Curtiss Bay of Baltimore. The 22-year-old Washington, D.C.–based pioneering aviator Tony Jannus was hired for the successful test flight in front of a large group of spectators. Two-seat aircraft and flight training were rare at the time. Company owner Edward Brown took the controls of the Lord Baltimore II alone for his first flight in an aircraft on 19 May. He climbed 50 feet and spun into the bay, not able to turn the aircraft around. The injured Brown did not attempt to fly again. Clyde Loose attempted to fly the Lord Baltimore II on 2 July, but wrecked in some bushes. The aircraft was reassembled soon after.

An announcement that the Brown aircraft would be flown to Washington D.C. via Annapolis was released. On 9 July 1911, Jannus attempted to fly the aircraft again configured as a hydroplane with Clyde Loose as a passenger. After three attempts, the aircraft was grounded with a failed radiator. Brown publicized the aircraft would fly to Frederick the next day.

The aircraft was tested through the summer. One flight by Loose on 27 July included Frank Brown Jr, son of Maryland's Governor Frank Brown.  Partner Don Swan flew the aircraft once to fifty feet and landed after he found he could not turn the aircraft. Swan's wife grounded him permanently afterward. The company was dissolved later in 1911.

Aircraft

References

Bibliography

Defunct aircraft manufacturers of the United States
Aviation in Maryland
Tear resistance. Tear resistance (or tear strength) is a measure of how well a material can withstand the effects of tearing.  It is a useful engineering measurement for a wide variety of materials by many different test methods.

Discussion
For example, with rubber, tear resistance measures how the test specimen resists the growth of any cuts when under tension, it is usually expressed in kN/m. Tear resistance can be gauged via the same ASTM D 412 apparatus used to measure tensile strength, modulus and elongation. ASTM D 624 can be applied to measure the resistance to the formation of a tear (tear initiation) and the resistance to the expansion of a tear (tear propagation). Regardless of which of these two is being measured, the sample is held between two holders and a uniform pulling force applied until the aforementioned deformation occurs. Tear resistance is then calculated by dividing the force applied by the thickness of the material.

Materials with low tear resistance sometimes have poor resistance to abrasion and when damaged will quickly fail (this includes hard materials, since hardness is not related to tear resistance).

Tear resistance of different materials
Substances with high tear resistance include epichlorohydrin, natural rubber and polyurethane. In contrast, materials such as silicone and fluorosilicone have low tear resistance.

Tear-yield ratio
The ratio of tear resistance to the yield strength is called the tear-yield ratio. It is a measure of notch toughness.

Standards by ASTM International
C1681-14 Standard Test Method for Evaluating the Tear Resistance of a Sealant Under Constant Strain
D1004-13 Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting
D1922-15 Standard Test Method for Propagation Tear Resistance of Plastic Film and Thin Sheeting by Pendulum Method
D1938-14 Standard Test Method for Tear-Propagation Resistance (Trouser Tear) of Plastic Film and Thin Sheeting by a Single-Tear Method
D2212-00(2015) Standard Test Method for Slit Tear Resistance of Leather
D2582-16 Standard Test Method for Puncture-Propagation Tear Resistance of Plastic Film and Thin Sheeting
D4932/D4932M-89(2014)e1 Standard Test Method for Fastener Rupture and Tear Resistance of Roofing and Waterproofing Sheets, Roll Roofing, and Shingles
E604-15 Standard Test Method for Dynamic Tear Testing of Metallic Materials

See also
Landfill liner properties - tear resistance
Tearing energy
Fracture mechanics

References

External links 
 Tear resistance on rlhudson.com

Solid mechanics
Deformation (mechanics)
Compression set. The compression set (ASTM D395) of a material is the permanent deformation remaining after compressing it. In specific methods, temperatures and percent compression are specified. The term is normally applied to soft materials such as elastomers and foams. Compression is normally measured in two ways: compression set A and compression set B.

Compression Set A

This has the formal name compression set under constant force in air. In compression set A a force of 1.8 kN is applied to the specimen for a set time at a set temperature. Compression set A is defined as the percentage of original specimen thickness after the specimen has been left in normal (uncompressed) conditions for 30 minutes.  CA, the compression set A is given by CA = [(to - ti) / to] * 100 
where to is the original specimen thickness and ti is the specimen thickness after testing.

Compression Set B

This has the formal name compression set under constant deflection in air. The specimen is compressed to 75% of its original height for a set time and at a set temperature (sample is compressed to .75 of its original height). Compression set B is (like Compression set A) defined as the percentage of specimen deflection after it has been left in normal (uncompressed) conditions for 30 minutes.  CB, the compression set B is given by CB = [(to - ti) / (to - tn)] * 100 
where to is the original specimen thickness, ti is the specimen thickness after testing and tn is the spacer thickness or the specimen thickness during the test.

References

Deformation (mechanics)
Kumho Polychem. Kumho Polychem is a part of South Korean conglomerate Kumho Petrochemical Group, operating a factory located in Yeosu Industrial Complex. It manufactures EPDM rubbers, TPVs and KEPA.

It was founded in 1985 and is currently the 3rd largest producer of EPDM in the world (220,000 tonnes per year.)

The company currently supplies its products for various uses including automobiles, hoses, seals and wire insulation.

Also it developed thermoplastic rubber, Innoprene, which has the elasticity of thermosetting rubber and the compatibility of thermoplastic, based on our 20 years’ experience in the production and research technology of EP rubber.

Current products' capacity: EP(D)M – 220,000 MT, TPV / KEPA 7,000 MT (as of January 1. 2016)

References

External links
 

Plastics companies of South Korea
ArduSat. ArduSat is an Arduino based nanosatellite, based on the CubeSat standard. It contains a set of Arduino boards and sensors. The general public will be allowed to use these Arduinos and sensors for their own creative purposes while they are in space.

ArduSat is created by NanoSatisfi LLC, an aerospace company which in the words of Phil Plait has "the goal to democratize access to space" and was founded by 4 graduate students from the International Space University in 2012.

ArduSat is the first satellite which will provide such open access to the general public to space. It is one of several crowdfunded satellites launched during the 2010s. Currently the project evolved to the company Because Learning.

Timeline of the project

Technical features

ArduSat-1 & ArduSat-X 

The ArduSat project currently consists in two identical satellites: ArduSat-1 and ArduSat-X.

See also

 2013 in spaceflight

References

External links

Satellites of the United States
CubeSats
Citizen science
2013 in spaceflight
Spacecraft launched in 2013
Kickstarter-funded spacecraft
Nanosatellites
Satellites deployed from the International Space Station
Secondary payloads
Officer's tool. An officer’s tool (also known as an A-tool, rex tool, or lock puller) is a forcible entry device used by firefighters and other first responders. Officer’s tools are designed to completely remove cylindrical locks from doors without causing major structural damage, allowing for direct access to the internal locking mechanism.

Officer’s tools can be used on any type of cylindrical lock, including rim locks, police locks, dead-bolts, or key-in-the-knob locks. A door that has had its lock cylinder removed can be outfitted with a new one afterward with only minor cosmetic damage, making officer’s tools a less destructive alternative to other forcible entry devices like fireman’s axes and battering rams.

Design and usage 
An officer’s tool is composed of two primary sections: a heavily padded metal handle, and a two-sided metal head. One side of the head terminates in a flat striking surface, while the other features two metal prongs that taper outward. The angle of the prongs resembles an upper-case letter A, hence the name "A-tool". Individual firefighters and fire departments may make modifications to officer's tools based on the types of locks and doors found in their area. A common modification involves adding metal spikes and forks to one end of the tool, similar to a Halligan bar.

To remove a cylindrical lock from a door using an officer’s tool, a user positions the head of the tool so that the exposed portion of the lock cylinder is directly between the tool’s prongs. The user then holds the tool at a slight angle and hits the striking surface with a blunt object until it is firmly wedged in place around the lock. At this point, the lock cylinder can be pulled out of the door by using the handle of the officer’s tool as a lever.

The door will still be locked after the lock cylinder is removed, as the internal locking mechanism will still be intact. Many officer’s tools come with shove knives capable of manipulating the locking mechanism directly, which ultimately unlocks and opens the door.

Officer’s tools are designed to cause minimal damage to doors and their internal locking mechanisms during the process of removing a lock cylinder. This is especially useful for doors that cannot be broken down easily or safely, such as those made of glass or outfitted with iron bars.

A similar device, the smaller K-tool, is also capable of removing lock cylinders from doors. K-tools can be used on locks that are too small or narrow to remove with an officer’s tool, or on locks that are so flush with a door that the prongs of an officer's tool cannot grip it properly.

See also 
 Door breaching
 Halligan bar

References

Firefighter tools
Locks (security device)
DigitalOptics Corporation. DigitalOptics Corporation (DOC) is a San Jose, California-based technology company that designs and manufactures imaging systems for smartphones. DOC’s capabilities include optical design, camera module design and manufacturing, MEMS manufacturing, and image processing algorithms.

In 2013, DOC introduced a camera module technology ( mems|cam) with a MEMS-based autofocus actuator. The technology is designed to replace voice coil motor components, while improving speed, power consumption, and precision of the autofocus function.

DigitialOptics also provides embedded image processing and computational photography algorithms, including its face beautification, face detection, and multi-focus products.

DigitalOptics Corporation operates as a wholly owned subsidiary of Xperi.  DOC consists of the imaging and optics-related businesses acquired by Xperi. since 2005.

History

1991 Digital Optics Corporation was founded out of the University of North Carolina at Charlotte to develop micro-optics
 2005 Tessera Technologies, Inc. acquires assets of Shellcase for image sensor packaging technology
2006 Digital Optics Corporation acquired by Tessera Technologies, Inc.
2007 Tessera Technologies, Inc. acquires EyeSquad, a developer of digital auto-focus and optical zoom solutions for camera modules
2008 Tessera Technologies, Inc. acquires Fotonation, provider of embedded imaging solutions
2008 Siimpel commences production of MEMS autofocus for Motorola handsets
2009 Tessera Technologies, Inc. acquires Israel-based Dblur Technologies, a developer of software lens technology
2010 Tessera Technologies, Inc. acquires Siimpel Corporation, a developer of MEMS-based camera solutions
2012  DigitalOptics to acquire assets of Vista Point camera module business from Flextronics
2013 DigitalOptics launches mems|cam product

References 

Manufacturing companies based in San Jose, California
Defunct electronics companies of the United States
Photonics companies
Optics manufacturing companies
2006 mergers and acquisitions
Echo (blog comment hosting service). Echo was a blog comment hosting service.

History
 
JS-Kit was started as a side project of Russian-born programmer and Cisco Security Engineer Lev Walkin, who released JS-Kit as a quickly-embeddable comment system for blogs in 2006. The venture grew into a full-on hosting service for comments, with Walkin becoming CTO, Khris Loux becoming CEO and Chris Saad becoming Chief Strategy Officer. As company and its product evolved, JS-Kit was rebranded as Echo in 2009.

Haloscan acquisition
Haloscan was one of the first third-party blog comment hosting services, established in 2002. Haloscan was acquired by JS-Kit in 2008. In 2009, Echo had requested users of Haloscan product to upgrade to its core service.

In 2012, it was announced that Echo would discontinue their comment hosting-exclusive services in favor of social media applications (i.e., USA Network's "Character Chatter" website feature, among other feedback features), with support for all remaining JS-Kit, Haloscan and Echo comment modules being withdrawn.

Other acquisitions
 SezWho (2009)

References

External links
 Echo website

Internet forum hosting
149 Squadron (Israel). 149 Squadron, often referred to as the Smashing or Shattering Parrot () squadron is a former unit of the Israeli Air Force. Active from 1976 to 1991, the squadron flew the A-4 Skyhawk and IAI Kfir.

History 
149 Squadron was activated at Etzion in July 1976, the IAF's eighth and penultimate A-4 squadron. It was initially equipped with the E model of the Skyhawk, made available when 140 Squadron converted to A-4Ns, though by 1978 it was operating N model Skyhawks as well.

From November 1980, while under the command of Lt. Col. Israel Parnas, 149 begun operating the new IAI Kfir C.2 alongside the Skyhawk, and by late 1981 had retired the older type. On May 4, 1981, the squadron lost one its Kfirs during dissimilar air combat training with IAF F-15 Eagles. Its pilot, Major Yoram Eitan, son of IDF Chief of the General Staff Rafael Eitan, was killed.
In 1982, with Israel's evacuation of the Sinai following the Camp David Accords, 149 Squadron moved to Ovda. On 19 July 1988, due to IAF downsizing and the need to provide additional civil airport capacity for Eilat, the squadron relocated to Hatzor. As other Kfir units eventually transitioned to the F-16 Fighting Falcon, 149 received additional aircraft and for a time may have been unusually large. It was finally disbanded in 1991, its aircraft stored at Ovda.

149 Squadron was reportedly the IAF's Operational Training Unit for the Kfir, tasked with qualifying new airmen on the type. As such, it also flew the two seat variant of the Kfir, the TC-2. The squadron also operated two Kfirs modified for the reconnaissance role and designated RC-2. The two aircraft, 419 and 451 (initially 819 and 851), were converted to mount camera noses developed for the Dassault Mirage. Their guns were removed, the radar warning receivers were moved aft, a Doppler radar installed under the forward fuselage, and they were installed with additional piping to carry power to the nose. When the squadron disbanded, the two aircraft were transferred to 144 Squadron.

Markings 
149 Squadron A-4 Skyhawks bore the IAF's standard 4-tone Skyhawk camouflage scheme, with the black character aircraft code applied on the nose. Unlike other IAF Skyhawk squadrons, it had no distinctive rudder colors.
Its Kfirs bore both the 2-tone 'compass gray' scheme and the F-16-style 4-tone scheme. In the late 1980s, its aircraft begun bearing blue and red tail flashes.

References

Bibliography

External links 

IAF Shattering Parrot Squadron at the A-4 Skyhawk Association website

Israeli Air Force squadrons
Renewable energy in Lithuania. Renewable energy in Lithuania constitutes a growing source of energy in the country.

In 2023, renewable energy sources accounted for 76.4% of electricity generation in the country, up from 18.2% in 2010 and 1.4% in 1990.

Statistics 
Renewable energy in Lithuania by type (as of 2022):

Biomass 
Solid biofuel or biomass represents the most common source of renewable energy in Lithuania. Most commonly used are firewood and wood as well as agricultural waste. It is primarily used to produce heat, but is also used for electricity production.

Biofuel

Biogas

Hydroelectricity 

 Kruonis Pumped Storage Plant, its main purpose is to provide a spinning reserve of the power system, to regulate the load curve of the power system 24 hours a day. Installed capacity of the pumped storage plant: 900 MW (4 units, 225 MW each).
 Kaunas Hydroelectric Power Plant, has a capacity of 100.8 MW.

Geothermal energy 
 Klaipėda Geothermal Demonstration Plant, the first geothermal heating plant in the Baltic Sea region.

Solar power 

In 2023, Lithuania had capacity of 1165 MW of solar power (compared to only 2.4 MWh power in 2010). 

As of 2012, Lithuania has 1,580 small (from several kilowatts to 2,500 kW) solar power plants with a total installed capacity of 59.4 MW which produce electricity for the country, and has an uncounted number of private power plants which make electricity only for their owners.

Wind power 
Installed wind power capacity in Lithuania and generation in recent years is shown in the table below:

See also
 Energy in Lithuania
 Renewable energy by country

References

External links

 
 
 
Energy in Lithuania
G&SWR 187 Class. The Glasgow and South Western Railway (GSWR) 187 class were a class of 0-4-2 steam locomotives designed for mixed traffic duties, by James Stirling in 1870. They formed a model for large numbers of similar 0-4-2 mixed traffic locomotives subsequently built on GSWR and other British railways.

Development 
James Stirling’s predecessor at the GSWR had been his brother Patrick, who built five classes of 0-4-2 locomotive for freight duties between 1856 and 1866. After Patrick left to join the Great Northern Railway, James sought to develop a version capable of a wider range of duties. The class has been described by Casserley as ‘probably the first engines coming within the modern definition of ‘mixed traffic’ locomotives.’ Twenty examples of the class were built in 1870-72, but the design was further developed by Stirling with his 208 and 221 mixed traffic 0-4-2 classes, of which sixty were built between 1873 and 1878.

The use of the 0-4-2 wheel arrangement for mixed traffic locomotives was later followed by Patrick Stirling on the GNR and by William Adams on his Jubilee class for the London and South Western Railway 1887–1894.

Withdrawal 
Seven examples were renewed by Manson in 1900-1901 and these survived until 1926-30. The remainder with withdrawn between 1897 and 1917.

References 

187
0-4-2 locomotives
Standard gauge steam locomotives of Great Britain
Railway locomotives introduced in 1870
Scrapped locomotives