omniomni/omni-engineering huggingface dataset:
Thermal airship. A thermal airship is an airship that generates buoyancy by heating air in a large chamber or envelope. The lower density of interior hot air compared to cool ambient air causes an upward force on the envelope. This is very similar to a hot air balloon, with the notable exception that an airship has a powered means of propulsion, whilst a hot air balloon relies on winds for navigation. An airship that uses steam would also qualify as a thermal airship.

Other types of airships use a gas that is lighter than air at ambient temperature, such as helium, as a lifting gas.

Some airship designs that use a lighter-than-air lifting gas heat a portion of the gas, which is usually maintained in enclosed cells to gain additional lift. Heating the lifting gas causes expansion of the gas in order to further lower the density of the lifting gas, which results in greater lift.

Advantages and disadvantages
Thermal airships have the advantage of being much less expensive than helium-based airships. They are also routinely deflated after each flight and can be readily packed for storage and/or transport, making them blimps rather than rigid airships.

Hot air craft produce much less uplift per unit volume than helium- or hydrogen-filled craft (about 30% depending on air conditions). This necessitates lighter construction, with fewer controls and hence more difficulty in maneuvering. This leads to:
lower airspeeds
difficulty in handling on the ground if the ground wind is above 5 knots
difficulty in steering, particularly at low air speeds
lack of elevator (pitch) control, causing the airship to pitch up or down in response to changes in the throttle setting (a motion called 'porpoising')

In recent years, the steering of these ships has improved somewhat. The most successful approach has been to use higher pressure in the tail fin structures than in the rest of the envelope, or to use an internal structure (see below).

History

The first public flight of a hot air airship was made by Don Cameron (UK) in a Cameron D-96 at the Icicle Meet in January 1973. The aircraft took 3 years to develop.

Envelope structures
Most thermal airships are non-rigid. Some are pressurized. In some cases, the pressurized air is taken from a duct located behind the propeller. In other cases, the pressurized air comes from a separate fan.

In 2006, a new type of envelope employing a tensile membrane structure was developed by Skyacht Aircraft. This design uses an unpressurized envelope and an internal structure that uses ribs made of aluminium to keep the envelope in shape. When not in use, the structure folds up in a manner similar to an umbrella. The structure also permits the mounting of a steerable engine/propeller on the tail of the aircraft. The tail-mounted propeller provides for vectored thrust steering, allowing tight turns.

Operation

Like hot air balloons, thermal airships are first inflated partially with cold (ambient temperature) air. Once the envelopes are sufficiently full, a propane burner is ignited and the inflation is completed using heated air.

See also
 Zeppelin

References

Airship configurations
Steam vehicles
Tensile membrane structures
Liberation Class. The Liberation Class was a class of 2-8-0 steam locomotives designed for heavy freight work in post-Second World War Europe. 120 were built by the Vulcan Foundry of Newton-le-Willows in 1946.

Design
They shared some features with the earlier WD Austerity 2-8-0 and WD Austerity 2-10-0 which in turn had been based on the LMS Stanier Class 8F.  They were however built to the continental loading gauge, but the design was intended to last, not a short-term kriegslok.

Distribution
Ten went to Luxembourg and the rest to Eastern Europe. The United Nations Relief and Rehabilitation Administration distributed them as follows:
 10 to as Luxembourg as  CFL class 47
 65 to Yugoslavia as  JŽ class 38; Đuro Đaković built 10 more 1957–1958
 30 to Poland as  PKP class Tr202
 15 Czechoslovakia as  ČSD class 459.0

Preservation
One Liberation class locomotive remains in Kraków, Poland Tr202-19 built in 1946.
A second (also not in working condition) is in Jaworzyna Slask, Lower Silesia, South West Poland Tr202-28.

References

External links 

 Tr202
 CFL class 47
 Vulcan Foundry Publicity Leaflet on the Liberation Class

Freight locomotives
Vulcan Foundry locomotives
2-8-0 locomotives
Railway locomotives introduced in 1946
Steam locomotives of Czechoslovakia
Steam locomotives of Luxembourg
Steam locomotives of Poland
Steam locomotives of Yugoslavia
Standard gauge locomotives of Yugoslavia
Standard gauge locomotives of Czechoslovakia
Standard gauge locomotives of Luxembourg
Standard gauge locomotives of Poland
Chemins de fer luxembourgeois locomotives
Czechoslovak State Railways locomotives
Polish State Railways steam locomotives
Lindstrand Balloons. Lindstrand Balloons was a manufacturer of hot air balloons and other aerostats. The company was started by Swedish-born pilot and aeronautical designer Per Lindstrand in Oswestry, England, as Colt Balloons (later Thunder & Colt Balloons, then Lindstrand Balloons) in 1978. Lindstrand Balloons was known for its leading-edge engineering, which included sophisticated testing and production facilities.

Lindstrand Balloons designed and built the hot air balloons flown by Per Lindstrand and Richard Branson on their record breaking flights; first across the Atlantic Ocean in 1987 and then the Pacific Ocean in 1990. Subsequently Lindstrand designed and built three Rozière balloons which Per Lindstrand and Branson and others used in their unsuccessful attempts to circumnavigate the Earth by balloon. Per Lindstrand played an instrumental role in making these flights possible, and was pilot for all of them.

Ownership structure

In the late-1990s, Cameron Holdings and its owner Don Cameron acquired two-thirds ownership of Lindstrand Balloons. Cameron bought the majority stake in Lindstrand Balloons from Rory McCarthy, a British industrialist associated with Richard Branson, who had invested in Lindstrand to support Branson's series of record-setting balloon flights. The remaining third of the company was owned by its founder Per Lindstrand, until 2003 when Per sold his remaining share to Cameron Holdings.

Despite Cameron's ownership, Lindstrand Balloons continued to operate as an independent company with separate management and its own distinct designs and products.

Lindstrand Technologies
Per Lindstrand independently operates a separate company, which designs and builds gas balloons, innovative buildings, specialized aerospace equipment (including an advanced parachute for the Beagle 2 Mars-lander) and cutting edge inflatable structures including aircraft hangars, plugs for fire-containment for road tunnels and flood prevention systems.

On 15 April 2015 it was reported that Lindstrand Balloons had closed, with 19 workers losing their jobs, citing the strength of the pound and terrorism threats in the Middle East as factors in the slow sales of balloons.

References

External links
 Lindstrand Hot Air Balloons Ltd. (UK company)
 Lindstrand Technologies Ltd. (UK company)
 Lindstrand Balloons US (independently owned US affiliate/licensee)

See also
 2012 Ljubljana Marshes hot air balloon crash
 hot air balloon
 hopper balloon
 Rozière balloon

Balloon manufacturers
Ballooning
Manufacturing companies of the United Kingdom
Aerospace engineering organizations
ZX8301. The ZX8301 is an Uncommitted Logic Array (ULA) integrated circuit designed for the Sinclair QL microcomputer. Also known as the "Master Chip", it provides a Video Display Generator, the division of a 15 MHz crystal to provide the 7.5 MHz system clock, ZX8302 register address decoder, DRAM refresh and bus controller. The ZX8301 is IC22 on the QL motherboard.

The Sinclair Research business model had always been to work toward a maximum performance to price ratio (as was evidenced by the keyboard mechanisms in the QL and earlier Sinclair models). Unfortunately, this focus on price and performance often resulted in cost cutting in the design and build of Sinclair's machines. One such cost driven decision (failing to use a hardware buffer integrated circuit (IC) between the IC pins and the external RGB monitor connection) caused the ZX8301 to quickly develop a reputation for being fragile and easy to damage, particularly if the monitor plug was inserted or removed while the QL was powered up. Such action resulted in damage to the video circuitry and almost always required replacement of the ZX8301.

The ZX8301, when subsequently used in the International Computers Limited (ICL) One Per Desk featured hardware buffering, and the chip proved to be much more reliable in this configuration.

See also 

 Sinclair QL
 One Per Desk
 List of Sinclair QL clones

References

External links
 http://www.worldofspectrum.org/qlfaq/Hardware

Gate arrays
Sinclair Research
A. C. Heidebrecht. Arthur C. Heidebrecht (born 1939) is a Canadian professor and civil engineer. He served as a faculty member at McMaster University from 1963 to 1997, dean of Engineering (1981–1989) and Vice-president Academic (1989–1994).

Born in Alberta, Canada, he studied at the University of Alberta and graduated with a B.Sc in Civil Engineering in 1960. He obtained his M.Sc and Ph.D. at Northwestern University in 1961 and 1963, respectively.

He is renowned for his research in earthquake engineering. In 2002, he was awarded an Honorary D.Sc degree from McMaster University.

References

1939 births
Living people
Canadian civil engineers
Engineers from Alberta
Academic staff of McMaster University
Canadian people of German descent
University of Alberta alumni
Galveston-class cruiser. Originally built as  light cruisers (CL) in the United States Navy during World War II, in 1957 three ships were re-designated as Galveston-class guided missile light cruisers (CLG) and fitted with the Talos long-range surface-to-air missile system.  During the two-year refit under project SCB 140, the aft superstructure was completely replaced and all aft guns were removed to make room for the twin-arm Talos launcher and a 46-missile storage magazine.  Three large masts were also installed in order to hold a variety of radars, missile guidance, and communications systems.  Little Rock and Oklahoma City were simultaneously converted into fleet flagships under SCB 140A, which involved removing two forward dual  and one triple  turrets, and replacing them with a massively rebuilt and expanded forward superstructure.  Galveston, in the non-flagship configuration, retained the Cleveland-class's standard forward weapons: three dual  and two triple  turrets.

A similar pattern was followed in converting three other  ships (Providence, Springfield, and Topeka) to operate the Terrier surface-to-air missile system, creating the .  Providence and Springfield were outfitted as fleet flagships, but Topeka was not.

Like the Providence class cruisers, the Galveston class ships suffered from serious stability problems caused by the topweight of the missile system. Indeed, the Galveston class ships were more affected by heavy Talos missile system than the Terrier equipped ships. Weight reduction measures and the use of ballast were necessary to improve stability. The cruisers, particularly Galveston, also suffered from hogging of the hull.

All three Galveston-class ships were decommissioned to the reserve fleet between 1970 and 1979.  In the 1975 cruiser realignment, Little Rock and Oklahoma City were reclassified as guided missile cruisers (CG).  The ships were stricken from the Naval Vessel Register between 1973 and 1979.  Galveston was scrapped in the mid-1970s, Oklahoma City was sunk as a target in 1999, and Little Rock is a museum ship in Buffalo, NY.

Ships in class

See also
 List of cruisers of the United States Navy

References

External links
hazegray.org
US Naval Historical Center

Cruiser classes
Aviat Husky. The Aviat Husky is a tandem two-seat, high-wing, utility light aircraft built by Aviat Aircraft of Afton, Wyoming.

It is the only all-new light aircraft that was designed and entered series production in the United States in the mid-to-late 1980s.

Development
Design work by Christen Industries began in 1985. The aircraft is one of the few in its class designed with the benefit of CAD software. The prototype first flew in 1986, and certification was awarded the following year.

With more than 650 aircraft sold between its introduction and 2008, the Husky was one of the best-selling light aircraft designs of the period.

Design

The Husky features a braced high wing, tandem seating and dual controls. The structure is steel tube frames and Dacron covering over all but the rear of the fuselage, plus metal leading edges on the wings. The high wing was selected for good all-around visibility, making the Husky ideal for observation and patrol roles.  Power is supplied by a relatively powerful (for the Husky's weight)  Textron Lycoming O-360 flat-four piston engine turning a constant speed propeller. In 2015 a reversible MT Propeller was approved under a Supplemental type certificate for better control during floatplane water operations.  The Husky's high power-to-weight ratio and low wing loading result in good short-field performance.

Options include floats, skis and banner and glider tow hooks.

Operational history
The Husky has been used for observation duties, fisheries patrol, pipeline inspection, glider towing, border patrol and other utility missions. Notable users include the US Department of the Interior and Agriculture and the Kenya Wildlife Service, which flies seven on aerial patrols of elephant herds as part of the fight against illegal ivory poaching.

Variants

The Husky comes in six versions:
Husky A-1
Certified on 1 May 1987. Maximum gross weight is . Powered by a Lycoming 0-360-A1P or a Lycoming O-360-C1G of 
Husky A-1A
Certified on 28 January 1998. Maximum gross weight is . Powered by a Lycoming 0-360-A1P of 

Certified on 28 January 1998. Powered by a Lycoming 0-360-A1P of  The A-1B can be modified to accept a Lycoming IO-360-A1D6 engine of  and an MT MTV-15-B/205-58 propeller under an STC.
Husky A-1B-160 Pup
Certified on 18 August 2003 without flaps and 21 October 2005 with flaps. Powered by a Lycoming 0-320-D2A, . The Pup has a smaller engine, a gross weight of  and a useful load of 
Husky A-1C-180

Certified on 24 September 2007. Powered by a Lycoming 0-360-A1P of . The 180 has a gross weight of  and a useful load of 
Husky A-1C-200
Certified on 24 September 2007. Powered by a Lycoming IO-360-A1D6 of . The 200 has a gross weight of  and a useful load of

Specifications (A-1C Husky)

See also

References
Notes

External links

 

Husky
High-wing aircraft
Single-engined tractor aircraft
1980s United States civil utility aircraft
Glider tugs
Aircraft first flown in 1986
Aircraft with fixed conventional landing gear
Single-engined piston aircraft
Physical coefficient. Physical coefficient is an important number that characterizes some physical property of a technical or scientific object under specified conditions. A coefficient also has a scientific reference which is the reliance on force.

Stoichiometric coefficient of a chemical compound 

To find the coefficient of a chemical compound, you must balance the elements involved in it.  For example, water:
H2O.
It just so happens that hydrogen (H) and oxygen (O) are both diatomic molecules, thus we have H2 and O2.  To form water, one of the O atoms breaks off from the O2 molecule and react with the H2 compound to form H2O.  But, there is one oxygen atom left.  It reacts with another H2 molecule.  Since it took two of each atom to balance the compound, we put the coefficient 2 in front of H2O:
2 H2O.
The total reaction is thus 2 H2 + O2 → 2 H2O.

Examples of physical coefficients
 Coefficient of thermal expansion (thermodynamics) (dimensionless) - Relates the change in temperature to the change in a material's dimensions.  
 Partition coefficient (KD) (chemistry) - The ratio of concentrations of a compound in two phases of a mixture of two immiscible solvents at equilibrium.
 Hall coefficient (electrical physics) - Relates a magnetic field applied to an element to the voltage created, the amount of current and the element thickness. It is a characteristic of the material from which the conductor is made.
 Lift coefficient (CL or CZ) (aerodynamics) (dimensionless) -  Relates the lift generated by an airfoil with the dynamic pressure of the fluid flow around the airfoil, and the planform area of the airfoil. 
 Ballistic coefficient (BC) (aerodynamics) (units of kg/m2) - A measure of a body's ability to overcome air resistance in flight. BC is a function of mass, diameter, and drag coefficient. 
 Transmission coefficient (quantum mechanics) (dimensionless) - Represents the probability flux of a transmitted wave relative to that of an incident wave.  It is often used to describe the probability of a particle tunnelling through a barrier.  
 Damping factor a.k.a. viscous damping coefficient (Physical Engineering) (units of newton-seconds per meter) - relates a damping force with the velocity of the object whose motion is being dampened.

References

Physical quantities
James R. Barr. James Robertson Barr A.M.I.E.E. (22 October 1884 – 5 December 1910) was a Scottish engineer and lecturer in Electrical Engineering at Heriot-Watt College, Edinburgh.

He was an apprentice to Bruce Peebles & Co. Ltd. and spent a year at the Leith Power Station. He then was  designer to the Electric Construction Company and took some plant to West Africa for erection.

In October 1905 he was appointed assistant lecturer in Electrical Engineering at Heriot Watt College.  He was elected associated member of the Institution of Electrical Engineers in 1906.

Despite his death  by tuberculosis at the age of 26, his 1908 textbook Principles of Direct-Current Electrical Engineering was revised and reprinted until the 1950s. The companion volume The Design of Alternating Current Machinery was written but not yet revised for publication at the time of his death. Robert Archibald from Dundee Technical College revised and corrected the proofs for its publication in 1913.

He was awarded three medals for student achievement:
 Physics & Mathematics, 1900–1901 Session, Leith Technical College.
 Advanced Electricity & Magnetism, 1901–1902 Session, Heriot-Watt College.
 Mathematics Stage III, 1902–1903 Session, Heriot-Watt College.

References

1884 births
1910 deaths
Scottish non-fiction writers
Academics of Heriot-Watt University
Scottish electrical engineers
Diffusion flame. In combustion, a diffusion flame is a flame in which the oxidizer and fuel are separated before burning. Contrary to its name, a diffusion flame involves both diffusion and convection processes. The name diffusion flame was first suggested by S.P. Burke and T.E.W. Schumann in 1928, to differentiate from premixed flame where fuel and oxidizer are premixed prior to burning. The diffusion flame is also referred to as nonpremixed flame. The burning rate is however still limited by the rate of diffusion. Diffusion flames tend to burn slower and to produce more soot than premixed flames because there may not be sufficient oxidizer for the reaction to go to completion, although there are some exceptions to the rule. The soot typically produced in a diffusion flame becomes incandescent from the heat of the flame and lends the flame its readily identifiable orange-yellow color. Diffusion flames tend to have a less-localized flame front than premixed flames.

The contexts for diffusion may vary somewhat. For instance, a candle uses the heat of the flame itself to vaporize its wax fuel and the oxidizer (oxygen) diffuses into the flame from the surrounding air, while a gaslight flame (or the safety flame of a Bunsen burner) uses fuel already in the form of a vapor.

Diffusion flames are often studied in counter flow (also called opposed jet) burners. Their interest is due to possible application in the flamelet model for turbulent combustion. Furthermore they provide a convenient way to examine strained flames and flames with holes. These are also known under the name of "edge flames", characterized by a local extinction on their axis because of the high strain rates in the vicinity of the stagnation point.

Diffusion flames have an entirely different appearance in a microgravity environment.  There is no convection to carry the hot combustion products away from the fuel source, which results in a spherical flame front, such as in the candle seen here. This is a rare example of a diffusion flame which does not produce much soot and does not therefore have a typical yellow flame.

See also
 Burke–Schumann flame
 Liñán's diffusion flame theory
 Emmons problem
 Premixed flame
 Oxidizing and reducing flames
 Oxy-fuel combustion process

References

External links
Diffusion flames in microgravity, NASA
Diffusion and edge flames in opposed-jet burners

Fire
Combustion engineering
Tschermigite. Tschermigite is a mineral form of ammonium alum, formula NH4Al(SO4)2·12(H2O).  It is found in burning coal seams, bituminous shale and fumaroles.  Because of its extreme water solubility it is unlikely to persist except in the dryest of conditions.   Discovered in 1852 at Cermiky, also known as Tschermig in Bohemia. It is colorless and named for where it was discovered.

References

Ammonium minerals
Aluminium minerals
Sulfate minerals
12
Cubic minerals
Minerals in space group 205