omniomni/omni-engineering huggingface dataset:
Ballistic foam. Ballistic foam is a foam that sets hard. It is widely used in the manufacture and repair of aircraft to form a light but strong filler for aircraft wings.  The foam is used to surround aircraft fuel tanks to reduce the chance of fires caused by the penetration of incendiary projectiles.

Ballistic foam is a type of polyurethane foam placed in the dry bays of aircraft. Ballistic foam prevents fires, adds strength to the structure, slows down the speed of shrapnel during attacks, and offers cost-effective protection.

Ballistic foam is placed in the dry bays to provide a barrier between the spark and the fuel. As bullets or shrapnel penetrate the mold line skin surrounding the outermost portions of the dry bay, the ballistic foam deprives sparks of oxygen. Thus when the article punctures the fuel tank, a fire is not started. Not only does the foam displace oxygen, but all gases, including explosive vapors which could magnify the destructive effects of ballistic attack. Dry bays, voids, may also contain “onboard ignition sources” like hot surfaces and electrical sparks which benefit both from a lack of gases and the fire-retardant nature of the foam. 

Ballistic foam strengthens aircraft by protecting it from fire as well as fluid while adding very little weight. The protection from fluid involves resisting damage by “moisture, hydrocarbon fuels, hydraulic fluids, and most common solvents”. The density of the foam varies with the type being used; Type 2.5 is a white to light amber foam weighing 2.5 pounds per cubic foot, while Type 1.8 is a pale blue to green foam weighing 1.8 pounds per cubic foot.

Chopped fiberglass strands embedded in the foam add to the structural integrity through physical support and shrapnel mitigation. The layer that strengthens the foam in turn strengthens the airframe. The layer of fiberglass also prevents shrapnel and bullets from rupturing the foam. The fiber glass then allows the damage caused by projectile penetration to heal more effectively.

The passive protection afforded by ballistic foam is very simple and inexpensive compared to active protection. One method of active protection is done by filling large dry bays with inert gases which will not sustain a flame. This process is very expensive and complex. Active protection only offers a “one time” chance for ballistic protection while the ballistic foam is always available.

See also
Vaporific effect

References

Foams
Roboreptile. The Roboreptile is a toy robot by WowWee. The Roboreptile has infrared and sound sensors, and is able to autonomously explore its environment while avoiding obstacles. It can also operate in different modes where it simulates behaviors of real animals. It is able to rear up on its hind legs and attack.  Roboreptile was released in China on the 28 April 2006 and to the rest of the world later that year. It is superficially similar to a theropod or a prosauropod dinosaur but being quadrupedal it's better equated to a silesaurid or a monitor lizard.

Features 
Biomorphic movements
Four-legged walking and low speed running; bipedal "attack" mode; jumping action
Flexible neck; whipping tail
Multi-sensory environmental awareness
Infrared vision sensors for obstacle avoidance and detection of movements
Sonic sensors for detection of sharp, loud sounds
Touch sensor for responding to human interaction
Five modes
Autonomous (default): Hungry and aggressive; explores and interacts with his environment searching for prey; attacking, roaring, biting behaviors
Direct control: Multi-layered 28 function remote including demo function and volume control
Program: Enter a sequence of up to 20 commands
Guard: Activates vision and sonic sensor with realistic screeching
Sleep
Three moods
Hungry: his "natural" (default) mood; activate the "feed" button on the remote and he will track down the signal
Satisfied: he calms down after eating
Hooded: he becomes subdued; depending upon human interaction, will either wake up hungry or fall asleep
Auto shut-off function

Robotyrannus 
Despite its namesake, Robotyrannus is not a robotic version of a Tyrannosaurus. The Robotyrannus is a variation of the Roboreptile with some cosmetic differences: horns on its head and a dorsal fin. It is currently being sold in the UK, Canada and the United States (although in the US it is generically called Roboreptile, despite being the Robotyrannus design). Regardless of the altered appearance, Robotyrannus is functionally identical to the original Roboreptile. It has been a RadioShack exclusive in United States, but the title was RoboReptile.

References

External links 
WowWee Robotyrannus's Official Home on the Web

Entertainment robots
Robotic dinosaurs
WowWee
2006 robots
Toy animals
Darrell Cornell. Darrell Eugene Cornell (August 19, 1932 - October 10, 1984) was Northrop's chief test pilot in the early 1980s. He was killed on October 10, 1984, at Suwon Air Base, while performing a demonstration flight for the South Korean Air Force (ROKAF). The F-20, 82-0062, c/n GG1001, N4416T, he was piloting stalled after a series of climbing rolls performed with flaps and gear extended. Cornell was not able to recover the aircraft from the uncontrolled stall. Cornell was also the lead test pilot for Northrop's RF-5E Tigereye, a reconnaissance version of the low-cost F-5E fighter aircraft.

He was featured in the April 1984 issue of LIFE magazine in an article entitled "Edwards Air Force Base Pilots", together with Doug Benefieds, Chuck Sewell, Tony LeVier, and Russell O'Quinn.

Cornell was born in Moorhead, Minnesota, grew up in Fargo, North Dakota, and was a former USAF pilot. He was an alumnus of North Dakota State University. He was also an astronaut candidate with NASA in 1963, although he was not selected to join Group 3. He began at Northrop in 1962. His display performances flying the F-20 in Paris, France (Le Bourget 1983) and Farnborough, England in 1984 are remembered by many as some of the finest ever performed at these airshows.

References

1932 births
1984 deaths
American test pilots
Aviators killed in aviation accidents or incidents
Military personnel from Minnesota
Military personnel from North Dakota
North Dakota State University alumni
People from Fargo, North Dakota
People from Moorhead, Minnesota
United States Air Force officers
Victims of aviation accidents or incidents in 1984
Victims of aviation accidents or incidents in South Korea
Multiplex Modellsport. Multiplex Modellsport GmbH & Co. KG of Bretten-Gölshausen, Germany is a manufacturer of hobby-grade radio control electronics, electric radio-controlled airplanes and electric helicopters.

Their aircraft models are molded of a proprietary expanded polypropylene foam known as Elapor.  The flexible nature of the material makes the company's models resistant to crash damage as well as easy assembly and repair with ordinary hobby-grade cyanoacrylate adhesives.  The two-part epoxy commonly used in model assembly will not bind Elapor, nor will so-called "foam safe" cyanoacrylate adhesives used in the assembly and repair of EPS foam models.

Products

Aircraft
Models range from small powered gliders such as the Cularis to "pusher prop jets" such as the FunJET pictured right, to electric "sportliners" such as the Blizzard, to the company's largest model, the Mentor.  The Mentor (now discontinued), a trainer aircraft which resembles a Cessna 180, is an electric-powered model similar in size and power to a .40 cubic inch/6.5cc glow engine-powered model.  It is large and powerful enough to be used as a glider tug and parts are packed with the kit to allow the Mentor to be used as such.

In 2010, the company introduced its first helicopter model, the Funcopter.  The model features an Elapor fuselage and a direct drive rotor system, eliminating the need for the drive gears and one-way bearings found in many other models.

Also introduced in 2010 was the FunJET Ultra. The original FunJET is a popular subject for modification, with heavily modified examples capable of greater than 130 MPH (210 km/h).  The Ultra addresses the problems inherent in such modifications with a combination of denser Elapor, improved aerodynamics with the elimination of the simulated wing tanks and an updated motor mount.

Radio control equipment
Multiplex's RoyalPRO line of aircraft and surface model radios are available in both North American and European frequency ranges including the spread spectrum 2.4 GHz band.  The company also markets a line of servos and electronic speed controls, again for both air and surface use.

International competitors
Competing brands of radio control systems include, Spektrum RC, Sanwa, Futaba, Graupner, Hitec, Japan Remote Control, KO Propo, and Acoms.

References

External links
 Multiplex Modelsport Germany
 
 Multiplex Modelsport USA
 2007 product review of the Multiplex FunJET at RCGroups.com
 Discussion thread for the FunJET Ultra at RCGroups.com
 Video of a highly modified FunJET powered by a Kolibri turbine, the world's smallest turbine engine

Companies based in Baden-Württemberg
Radio-controlled transmitter
Radio-controlled aircraft
German brands
Model Aeronautics Association of Canada. The Model Aeronautics Association of Canada (MAAC) is the official organization for all forms of the aeromodelling hobby, for model aircraft hobbyists living in Canada. Based in Burlington, Ontario, it was founded in 1949, and presently has over 5000 members. MAAC is responsible for instituting official policies and regulations and guidelines. This includes radio frequencies, noise restrictions, and flying clubs. They organize flying events across Canada, and provide liability insurance coverage to its members.

MAAC produces a magazine, Model Aviation Canada, which is included in the yearly membership fees, containing regional reports from elected zone directors, articles and model reviews from around the country.

MAAC offers guidelines for the Wings program, teaching beginners how to safely operate an aircraft.

See also
 Academy of Model Aeronautics, the United States brother organization of aeromodeling

External links 
 Model Aviation Canada - MAAC Magazine website.
 Academy of Model Aeronautics - United States sister organization.

Aviation organizations based in Canada
Clubs and societies in Canada
Sports governing bodies in Canada
Model aircraft associations
British Rail Class 105. The British Rail Classes 105 and 106 diesel multiple units were built by Cravens Ltd. of Sheffield from 1956 to 1959. The class were built with a side profile identical to British Railways Mark 1 carriage stock, using the same doors and windows.  None were selected for refurbishment. The last passenger car was withdrawn from service in 1988.

Originally AEC engined vehicles were class 105 and Leyland engined vehicles were class 106, but in the late 1970s they all became class 105s.

Usage

The Class 105 DMUs were used chiefly on Eastern Region services around Hull, Lincolnshire, East Anglia and local services to/from . Units initially designated to work on the former Midland and Great Northern Joint Railway lines were moved to services from London King's Cross upon the closure of the M&GN joint lines in 1959. Units were also used on the London Midland Region and in Scotland, particularly in Aberdeenshire. The closure of many of these lines in the 1960s resulted in their dispersal throughout Great Britain, notably to Tyseley depot near Birmingham. The electrification of the lines from London King's Cross and the introduction of the Class 313 EMUs in 1976 led to the withdrawal of many Cravens units.

Norwich was the last depot to operate the Cravens units, with set 30 being returned to green livery, and gaining some celebrity status towards the end of its service life. The unit was, however, contaminated with asbestos and consequently scrapped.

Orders

Technical details
 Builder: Cravens
 Introduced: 1956
 Coupling Code: Blue Square
 Body: 57 ft 6 in x 9 ft 2 in 
 Engines: Two BUT, 150 bhp
 Transmission: Standard mechanical

For coupling codes see British United Traction

Preservation

Due to the use of asbestos in their construction, and extended usage by BR, the class has fared very badly in preservation. 51485 and 56121 were preserved by the West Somerset Railway but moved to the East Lancashire Railway in 1997 where they have been restored after asbestos stripping. 56456 is based on the Llangollen Railway, working initially with a Class 127.  The National Railway Museum had intended to preserve 53812 - which had been stripped of asbestos but a lack of space prevented this car and the Class 100 coupled to it from being moved to York and they were vandalised beyond repair at Crewe.

Models
Since 2010, Bachmann has produced 00 scale models of the class 105 in both BR green and BR blue liveries.

References

Sources

Further reading

External links
 History of the Class 105s

105
Cravens multiple units
Train-related introductions in 1959
KO PROPO. KO PROPO is a brand of radio control equipment and humanoid robot (KHR-1) by Kondo Kagaku, established in Tokyo, Japan in 1945.

In 1982 KO PROPO introduced the Expert EX-1, reported to have been the first to integrate a pistol grip into a transmitter device with a gun trigger to act as the throttle, which later became a popular fixture in radio controlled transmitters.

 the company had won 32 IFMAR World titles.

References

External links 
 KO PROPO USA

Japanese companies established in 1945
Companies based in Tokyo
Radio-controlled transmitter
Robotics companies of Japan
Robotics in Japan
Science and technology in Japan
Japanese brands
Technology companies established in 1945
László Heller. Heller László (19071980) was a Hungarian professor and mechanical engineer credited with inventing the Heller–Forgó dry cooling tower system for power stations.

Biography 
Born in Nagyvárad (now Oradea, Romania), Heller took a degree in mechanical engineering in 1931 at the Eidgenössische Technische Hochschule in Zurich.

In the 1940s the first high-pressure industrial power station was built according to his plans. It was around this time that he invented the Heller–Forgó system.

In 1951 he was awarded the Kossuth Prize and moved to the Budapest University of Technology and Economics, aka Technical University of Budapest. He organized its Department of Energetics, where he worked as a professor. He was a large contributor to the domain of statics, and helped establish the concept of entropy for engineering practices.

In 1962 he became a full member of the Hungarian Academy of Sciences.

Heller–Forgó system 

The Heller–Forgó system is named after Heller and László Forgó (1907–1985), the active collaborator in the industrial implementation of the system. It was developed by 1958, and the international sales pitch was set the same year.

Also known as the Indirect Dry Cooling System, it solved an important problem at power stations by utilizing cooling water more efficiently. The main point of their invention was to condense the vacuum steam using an injection of cool water. The still-warm water enters into the fine-gilled heat exchanger, cools down and becomes usable again for when the cycle is repeated. Installations include a water-cooled steam condenser, circulating machine groups, circulating water mains and a dry cooling tower which contains Forgó-type water-to-air heat exchangers. Heller's key achievement was to obtain the least condenser temperature for a given temperature of incoming cooling water by keeping the terminal temperature difference (TTD) as low as possible. The heat transfer between the working fluid and the cooling air is achieved by convection only and not by evaporation as in a wet cooling tower.

The firm set up by Heller and Forgo attracted attention from MDAX-listed GEA Group which held its shares from its privatization in 1992, until 2020 when the EGI firm was sold to Hungary’s monopoly power company, state-owned MVM Group. 

In 2023 the system attracted the attention of some Iranian academics who were interested in the replacement of a wet cooling tower.

Awards, honors and legacy 

Asteroid 276975 Heller, discovered by Hungarian astronomer Krisztián Sárneczky at Piszkéstető Station in 2004, was named in his honor. The official  was published by the Minor Planet Center on 8 October 2014 ().

References

External links 

 Biography of Heller
 News on an implementation of the Heller - Forgó system

1907 births
1980 deaths
Hungarian Jews
20th-century Hungarian engineers
20th-century Hungarian inventors
Burials at Kozma Street Cemetery
Poloxamer 407. Poloxamer 407 is a hydrophilic non-ionic surfactant of the more general class of copolymers known as poloxamers. Poloxamer 407 is a triblock copolymer consisting of a central hydrophobic block of polypropylene glycol flanked by two hydrophilic blocks of polyethylene glycol (PEG). The approximate lengths of the two PEG blocks is 101 repeat units, while the approximate length of the propylene glycol block is 56 repeat units. This particular compound is also known by the BASF trade name Pluronic F-127 or by the Croda trade name Synperonic PE/F 127. BASF also offers a pharmaceutical grade, under trade name Kolliphor P 407.

Uses
Most of the common uses of poloxamer 407 are related to its surfactant properties. For example, it is widely used in cosmetics for dissolving oily ingredients in water. It can also be found in multi-purpose contact lens cleaning solutions, where its purpose there is to help remove lipid films from the lens. It can also be found in some mouthwashes. There is research ongoing for using poloxamer 407 for aligning severed blood vessels before gluing them surgically. Poloxamer 407 can also be used for its thermogelling properties in aqueous media. 

Poloxamer 407 is approved by the FDA for use as an excipient in a range of pharmaceutical dosage forms, and is listed in the Inactive Ingredient Database (IID).

Poloxamer 407 is used in bioprinting applications due to its unique phase-change properties. In a 30% solution by weight, poloxamer 407 forms a gel solid at room temperature but liquifies when chilled to . This allows poloxamer 407 to serve as a removable support material, particularly for creating hollow channels or cavities inside hydrogels. In this role, it is often referred to as a "sacrificial ink" or a "fugitive ink".

Reports of adverse effects
It was reported in The Australian newspaper 18 November 2006 that this common ingredient in toothpaste and mouthwash can cause high cholesterol in mice. A team from the Centre for Ageing and the ANZAC Research Institute in Sydney used it as a tool to demonstrate that cells in the liver behave like a sieve. They gave a high dose (1 gram per kilogram of body weight) of poloxamer 407 to mice, which blocked 80% of the pores in liver cells that absorb lipoproteins, leading to a 10-fold increase in plasma lipid levels. However, the dose used is far higher than a person would be exposed to in toothpaste or mouthwash.

Potential degradation by sonication 
Wang et al. reported that aqueous solutions of poloxamer 188 and poloxamer 407 sonicated in the presence or absence of multi-walled carbon nanotubes (MWNTs) can become highly toxic to cultured cells. The toxicity correlated with the sonolytic degradation of the polymers.

References

External links
ChemSub Online: Poloxamer 407
BASF Pharma Solutions: Poloxamers
www.croda.com/healthcare/poloxamers

Non-ionic surfactants
Porosimetry. Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter, total pore volume, surface area, and bulk and absolute densities.

The technique involves the intrusion of a non-wetting liquid (often mercury) at high pressure into a material through the use of a porosimeter.  The pore size can be determined based on the external pressure needed to force the liquid into a pore against the opposing force of the liquid's surface tension.

A force balance equation known as Washburn's equation for the above material having cylindrical pores is given as:

 = pressure of liquid
 = pressure of gas
 = surface tension of liquid
 = contact angle of intrusion liquid
 = pore diameter

Since the technique is usually performed within a vacuum, the initial gas pressure is zero.  The contact angle of mercury with most solids is between 135° and 142°, so an average of 140° can be taken without much error.  The surface tension of mercury at 20 °C under vacuum is 480 mN/m.  With the various substitutions, the equation becomes:

As pressure increases, so does the cumulative pore volume.  From the cumulative pore volume, one can find the pressure and pore diameter where 50% of the total volume has been added to give the median pore diameter.

See also
 BET theory, measurement of specific surface
 Evapoporometry
 Porosity
 Wood's metal, also injected for pore structure impregnation and replica

References

Measurement
Scientific techniques
Porous media
Overlayer. An overlayer is a layer of adatoms adsorbed onto a surface, for instance onto the surface of a single crystal.

On single crystals
Adsorbed species on single crystal surfaces are frequently found to exhibit long-range ordering; that is to say that the adsorbed species form a well-defined overlayer structure. Each particular structure may only exist over a limited coverage range of the adsorbate, and in some adsorbate/substrate systems a whole progression of adsorbate structure are formed as the surface coverage is gradually increased.

The periodicity of the overlayer (which often is larger than that of the substrate unit cell) can be determined by low-energy electron diffraction (LEED), because there will be additional diffraction beams associated with the overlayer.

Types
There are two types of overlayers: commensurate and incommensurate. In the former the substrate-adsorbate interaction tends to dominate over any lateral adsorbate-adsorbate interaction, while in the latter the adsorbate-adsorbate interactions are of similar magnitude to those between adsorbate and substrate.

Notation
An overlayer on a substrate can be notated in either Wood's notation or matrix notation.

Wood's notation
Wood's notation takes the form

where M is the chemical symbol of the substrate, A is the chemical symbol of the overlayer,  are the Miller indices of the surface plane, R and  correspond to the rotational difference between the substrate and overlayer vectors, and the vector magnitudes shown are those of the substrate ( subscripts) and of the overlayer ( subscripts). This notation can only describe commensurate overlayers however, while matrix notation can describe both.

Matrix notation
Matrix notation differs from Wood's notation in the second term, which is replaced by the  matrix that describes the overlayer primitive vectors in terms of the substrate primitive vectors:
, where 
and so hence matrix notation has the form

See also
 Surface reconstruction
 Superstructure
 LEED#Superstructures

Citations

References

Textbooks

Websites
 

Surface science
Condensed matter physics