omniomni/omni-engineering huggingface dataset:
Testing, adjusting, balancing. In heating, ventilation, and air conditioning (HVAC), testing, adjusting and balancing (TAB) are the three major steps used to achieve proper operation of heating, ventilation, and air conditioning systems. TAB usually refers to commercial building construction and the specialized contractors who employ personnel that perform this service.

In general, the TAB specialist performs air and hydronic measurements on the HVAC systems and adjusts the flows as required to achieve optimum performance of the building environmental equipment. The balancing is usually based upon the design flow values required by the Mechanical Engineer for the project, and the TAB contractor submits a written report which summarizes the testing and balancing and notes any deficiencies found during the TAB work. Many times facility managers will use a TAB contractor to assist in identifying preexisting or common issues with a facility. While not necessary to be a TAB contractor, many contractors tend to hold professional air balancing certifications.

Testing
Testing is the use of specialized and calibrated instruments to measure temperatures, pressures, rotational speeds, electrical characteristics, velocities, and air and water quantities for an evaluation of equipment and system performance.

Adjusting
Adjusting is the final setting of balancing devices such as dampers and valves, adjusting fan speeds and pump impeller sizes, in addition to automatic control devices such as thermostats and pressure controllers to achieve maximum specified system performance and efficiency during normal operation.

Balancing
Balancing is the methodical regulation of system fluid flows (air or water) through the use of acceptable procedures to achieve the desired or specified design airflow or water flow. When beginning the balance of a system, you must locate the terminal with the least amount of flow in regards to the engineer's drawing. Once the "low" terminal has been located, you can then proceed to adjust all other diffusers/grilles (air) or circuit balancing valves (water) to proportionally match the original "low" terminal. There must be at least one terminal that is wide open to achieve optimum efficiency.

References 

Heating, ventilation, and air conditioning
USS Hatteras (AVP-42). What would have been the third USS Hatteras (AVP-42) was a proposed United States Navy seaplane tender that was never laid down.

Construction and commissioning 
Hatteras was to have been one of 41 Barnegat-class small seaplane tenders the U.S. Navy planned to commission during the early 1940s, and was to have been built at Houghton, Washington, by the Lake Washington Shipyard. However, by the spring of 1943 the Navy deemed that number of seaplane tenders excess to requirements, and decided to complete four of them as motor torpedo boat tenders and one as a catapult training ship.  In addition, the Navy also decided to cancel six of the Barnegat-class ships prior to their construction, freeing up the diesel engines that would have powered them for use in escort vessels and amphibious landing craft.

Hatteras became one of the first four ships to be cancelled when the Navy cancelled its contract with Lake Washington Shipyard for her construction on 22 April 1943.

References 
 
 NavSource Online: Service Ship Photo Archive Small Seaplane Tender (AVP) Index

Cancelled ships of the United States Navy
World War II auxiliary ships of the United States
Barnegat-class seaplane tenders
Ships built at Lake Washington Shipyard
Simulation Open Framework Architecture. Simulation Open Framework Architecture (SOFA) is an open source framework primarily targeted at real-time physical simulation, with an emphasis on medical simulation. 

It is mostly intended for the research community to help develop newer algorithms, but can also be used as an efficient prototyping tool or as a physics engine.

Features
Based on an advanced software architecture, SOFA allows users to:
 Create complex and evolving simulations by combining new algorithms with existing algorithms
 Modify most parameters of the simulation (deformable behavior, surface representation, solver, constraints, collision algorithm, ...) by simply editing a XML file
 Build complex models from simpler ones using a scene graph description
 Efficiently simulate the dynamics of interacting objects using abstract equation solvers
 Reuse and easily compare a variety of available methods
 Transparently parallelize complex computations using semantics based on data dependencies
 Use new generations of GPUs through the CUDA API to greatly improve computation times

Scene graph
A key aspect of SOFA is the use of a scene graph to organize and process the elements of a simulation while clearly separating the computation tasks from their possibly parallel scheduling. The description of a SOFA simulation can easily be done in an XML file. For even more flexibility, a Python plugin allows scripting simulations using the Python language. Basically, a SOFA scene-graph is composed with:
 Nodes: used to categorise the components and keep the XML file clean (mechanical node, collision node, visual node, ...)
 Components: main elements used to build a scene (solver component, forcefield component, rendering component, ...)
 Data: everything that components have to deal with (forces, velocities, positions, ratios, ...)

Plugins
To extend its capacities and provide more features, SOFA is bundled with a lot of plugins:
 Drivers for VR / haptic / simulation devices (Geomagic®, ARTTrack™, Novint® Falcon™…)
 Visualization and simulation of medical images
 Python scripting
 Parallelization:
 Multithreading
 GPU computing using the CUDA API

Community

SOFA Day
Organized each year, the SOFA Day is a one-day event dedicated to SOFA. This event is open to everyone interested in SOFA, from beginner to advanced users. It contains an introduction to SOFA, several tutorials (adapted to the audience) and a large time to experience SOFA with the help of the instructors.

SOFA Consortium
Exactly ten years after the first commit in SOFA, Inria founded the SOFA Consortium in December 2015. 
The Consortium missions are to:
 Represent the identity of SOFA
 Organize and develop the community
 Distribute and make SOFA more stable

See also

 Graphics processing unit (GPU)
 Soft body dynamics
 Rigid body dynamics
 Collision detection
 VRPN

References

External links
 SOFA website

Computer physics engines
Computational science
Simulation software
Medical simulation
Health software
Millennium Tower (Abuja). The Millennium Tower and Cultural Centre project is one of a number of projects in the Central District of Nigeria's capital city of Abuja. At , it is the tallest artificial structure in Abuja. The tower was designed by Manfredi Nicoletti and is part of the Nigeria National Complex which also includes the Nigerian Cultural Centre, an eight-storey, low rise, pyramid shaped Cultural Centre. Construction for the tower started in 2006 and was topped out in 2014 whilst the cultural centre is still under construction.

The site is served by a main road, so the two structures will be linked via an underground arcade. The tower consists of three cylindrical concrete pillar-like structures varying in height and linked together near the tower's first peak using a disc-shaped section that is intended to house in its two floors an observation deck and a viewing restaurant. Around the pillars of the tower, three transparent stainless steel wings wrap around the base of the tower and gradually open outwards in a fan-like fashion as they extend up the height of the tower.

See also
 List of towers

References

External links
 Manfredi Nicoletti Abuja National Complex project
 
 Construction photo on Immaginionline.net

Buildings and structures under construction in Nigeria
Neo-futurist architecture
Buildings and structures in Abuja
Event (synchronization primitive). In computer science, an event (also called event semaphore) is a type of synchronization mechanism that is used to indicate to waiting processes when a particular condition has become true.

An event is an abstract data type with a boolean state and the following operations:

 wait - when executed, causes the suspension of the executing process until the state of the event is set to true. If the state is already set to true before wait was called, wait has no effect.
 set - sets the event's state to true, release all waiting processes.
 clear - sets the event's state to false.

Different implementations of events may provide different subsets of these possible operations; for example, the implementation provided by Microsoft Windows provides the operations wait (WaitForObject and related functions), set (SetEvent), and clear (ResetEvent).  An option that may be specified during creation of the event object changes the behaviour of SetEvent so that only a single thread is released and the state is automatically returned to false after that thread is released.

Events short of reset function, that is, those which can be completed only once, are known as futures. Monitors are, on the other hand, more general since they combine completion signaling with mutex and do not let the producer and consumer to execute simultaneously in the monitor making it an event+critical section.

References

External links 

 Event Objects, Microsoft Developer Network
 Thread Synchronization Mechanisms in Python 

Concurrency control
Synchronization primitive
Raymond A. Litke. Raymond A. Litke (1920-1986) was an American electronic engineer, the inventor of a practical wireless microphone, and the first to patent the wireless microphone. He was born and raised on a farm near Alma, Kansas, but spent most of his adult life in San Jose, California.

Wireless microphone
Litke invented a wireless microphone in 1957 while employed as an electronics expert at San Jose State College. His supervisor challenged him to invent a microphone to use in educational presentations which would be free of wires.

Litke’s wireless mike resembled a silver tube with “a microphone at the top, a transmitter in the middle and its battery power supply at the bottom.” It was 6 inches long, 1 inch in diameter, and weighed 7 ounces; the device had a broadcast range of up to a half-mile. Two types of mikes were available: lavalier and hand-held. A companion receiver, weighing 17 pounds, completed the portable sound system.

Although Litke prototyped the wireless microphone in 1957, he did not file for a patent until May 8, 1961. U.S. Patent No. 3,134,074 was officially granted on May 19, 1964. His microphone is sometimes also called the “Vega-Mike” after the Vega Electronics Corporation which first manufactured it as a product. Vega sold other electronics items and tapes developed by Litke.

Litke's wireless microphone was first tested at the Olympic trials held at Stanford University in 1959. Next, the American Broadcasting Company (ABC television) tested the microphone at the Democratic and Republican Conventions in 1960. Candidates John F. Kennedy and Richard Nixon were among the first celebrities to use the Vega-Mike. TV anchor John Daly praised Litke's invention on the ABC television news broadcast in July 1960. Daly introduced it to Americans with the words: "This is a Vega-Mike" and went on to explain it "is a wireless microphone, six inches long... without any wires of any kind...." Daly pointed out it could be used to broadcast "within the (convention) hall or outside... without the inconvenience of interconnecting microphone cables...." Even the Federal Communications Commission was impressed with it. The FCC gave him 12 frequencies instead of the one he was seeking.

Other accomplishments
In the 1960s Litke worked at the University of California, San Francisco Medical Center as the chief engineer of Educational Television and as an electronics expert. By 1961 he had worked for the University of California system for ten years.

References

1920 births
1986 deaths
People from Wabaunsee County, Kansas
People from San Jose, California
20th-century American inventors
National Highway 77 (India, old numbering). National Highway 77  is a National Highway of India entirely within the state of Bihar that links Hajipur to  Sonbarsa near India-Nepal border, and is  long.

See also 
 National Highway
 List of National Highways
 National Highways Development Project
The National Highway has very important from commercial Point view as it connects North Bihar with South Bihar. It also important because it directly connects south Bihar with the International Border of Nepal.

References 

77
National highways in India (old numbering)
Nanomagnet. In magnetism, a nanomagnet is a nanoscopic scale system that presents spontaneous magnetic order (magnetization) at zero applied magnetic field (remanence).

The small size of nanomagnets prevents the formation of magnetic domains (see single domain (magnetic)). The magnetization dynamics of sufficiently small nanomagnets at low temperatures, typically single-molecule magnets, presents quantum phenomena, such as macroscopic spin tunnelling. At larger temperatures, the magnetization undergoes random thermal fluctuations (superparamagnetism) which present a limit for the use of nanomagnets for permanent information storage.

Canonical examples of nanomagnets are grains of ferromagnetic metals (iron, cobalt, and nickel) and single-molecule magnets. The vast majority of nanomagnets feature transition metal (titanium, vanadium, chromium, manganese, iron, cobalt or nickel) or rare earth (Gadolinium, Europium, Erbium) magnetic atoms.

The ultimate limit in miniaturization of nanomagnets was achieved in 2016:   individual Ho atoms  present remanence when  deposited on an atomically thin layer of MgO coating a silver film was reported by scientists from EPFL and ETH, in Switzerland.  Before that, the  smallest nanomagnets reported, attending to the number of magnetic atoms, were double decker phthalocyanes  molecules with only one rare-earth atom.  Other  systems presenting remanence are nanoengineered Fe chains, deposited on Cu2N/Cu(100) surfaces, showing either Neel  or ferromagnetic ground states with in systems with as few as 5  Fe atoms with S=2.  Canonical single-molecule magnets are the so-called Mn12 and Fe8 systems, with 12 and 8 transition metal atoms each and both with spin 10 (S = 10) ground states.

The phenomenon of zero field magnetization requires three conditions:
 A ground state with finite spin
 A magnetic anisotropy energy barrier
 Long spin relaxation time.

Conditions 1 and 2, but not 3, have been demonstrated in a number of nanostructures, such as nanoparticles, nanoislands, and quantum dots with a controlled number of magnetic atoms (between 1 and 10).

References

Further reading 
 

Magnetism
Hydraulic recoil mechanism. A hydraulic recoil mechanism is a way of limiting the effects of recoil and adding to the accuracy and firepower of an artillery piece.

Description 

The idea of using a water brake to counteract the recoil of naval cannons was first suggested to the British Admiralty by Carl Wilhelm Siemens in early 1870s, but it took about a decade for other people (primarily Josiah Vavasseur) to commercialize the idea.

The usual recoil system in modern quick-firing guns is the hydro-pneumatic recoil system.  In this system, the barrel is mounted on rails on which it can recoil to the rear, and the recoil is taken up by a cylinder which is similar in operation to an automotive gas-charged shock absorber, and is commonly visible as a cylinder mounted parallel to the barrel of the gun, but shorter and smaller than it.  The cylinder contains a charge of compressed air, as well as hydraulic oil; in operation, the barrel's energy is taken up in compressing the air as the barrel recoils backward, then is dissipated via hydraulic damping as the barrel returns forward to the firing position.  The recoil impulse is thus spread out over the time in which the barrel is compressing the air, rather than over the much narrower interval of time when the projectile is being fired.  This greatly reduces the peak force conveyed to the mount (or to the ground on which the gun has been emplaced).

See also
Canon de 75 modèle 1897, the first field gun employing a hydro-pneumatic recoil mechanism
List of British ordnance terms

External links 
A "cutaway" animation of the Canon de 75 modèle 1897 showing the parts and operation of its revolutionary recoil mechanism

References 

Artillery components
Westland Dreadnought. The Westland Dreadnought was an experimental single-engined fixed-wing monoplane design for a mail plane created to test the aerodynamic wing and fuselage design ideas of Woyevodsky. It was designed and built by British aircraft manufacturer Westland Aircraft for the Air Ministry. Only a single aircraft was built, and it crashed on its initial flight, badly injuring the test pilot.

Design and development
The Dreadnought was distinct for its futuristic design and method of construction, based on the theories of the Russian inventor N. Woyevodsky. After preliminary tests of the idea were tried in a wind tunnel and met with some degree of success, the design was given to Westland Aircraft to construct an aircraft. The design at the time was for a 70 ft wingspan twin-engine aircraft. The design was aerodynamically advanced, featuring a continuous aerofoil section over all parts of the aircraft, including the fuselage and unusually for British aircraft at that time, had no form of wing bracing. Construction was all-metal, comprising drawn channeling with a skin of corrugated sheet panels. Although conceived as a twin-engined type with retractable undercarriage, the design that emerged was fitted with a 450-horsepower Napier Lion II 12 cylinder engine that allowed the Dreadnought speeds of up to 102 miles per hour and fixed undercarriage.

Operational history
On completion of the Dreadnought, the pilot Arthur Keep carried out taxi trials and short airborne hops. On 9 May 1924, he took off for its first flight test. The aircraft was initially stable, it soon became clear that Keep was losing control and not long after, at a height of about , the Dreadnought stalled and crashed. Thrown from the aircraft, Keep suffered severe injuries and later had both legs amputated. He remained with the company and did not retire until 1935. After this failure, the Dreadnought design was abandoned, although the ideas that were conceived and used in its making were visibly an advancement in aircraft and are appreciated as such in the present day.

Specifications

See also
 Junkers – earlier pioneer of several all-metal monoplane types with corrugated skin.
 McDonnell XP-67 Bat – a later design with all-aerofoil profiles.
 Stout Batwing Limousine

References
Notes

Bibliography

 
 James, Derek N. Westland Aircraft since 1915. London: Putnam, 1991. .
 Lukins, A.H. The Book of Westland Aircraft. Leicester, UK: Harborough, 1944.
 Mondey, David. Westland: 2 Westland. London: Jane's, 1982. p. 17.

External links

 A Chance Which Westland Missed Flight 1965

1920s British experimental aircraft
Dreadnought
Single-engined tractor aircraft
Aircraft first flown in 1924
Mid-wing aircraft
Aircraft with fixed conventional landing gear
Random logic. Random logic is a semiconductor circuit design technique that translates high-level logic descriptions directly into hardware features such as AND and OR gates. The name derives from the fact that few easily discernible patterns are evident in the arrangement of features on the chip and in the interconnects between them. In VLSI chips, random logic is often implemented with standard cells and gate arrays.

Random logic accounts for a large part of the circuit design in modern microprocessors. Compared to microcode, another popular design technique, random logic offers faster execution of processor opcodes, provided that processor speeds are faster than memory speeds. A disadvantage is that it is difficult to design random logic circuitry for processors with large and complex instruction sets. The hard-wired instruction logic occupies a large percentage of the chip's area, and it becomes difficult to lay out the logic so that related circuits are close to one another.

References

Instruction processing
Microheater. Microheaters are small high-power heaters, with precise control, that can offer temperatures in excess of 1000C, even up to 1900C. Microheaters provide for accurate high temperature control, for example in electron microscopes, pressure-anvil cells or for enhancing fiberheaters.  Generally speaking, the heating method for microheaters involves conversion of electrical work to high density heat.  With the increase in the temperature demanded, microheater heating materials change from metallic (non-brittle GAXP) to metal-ceramic like materials (MoSi2) which tend to be brittle.  With an increase in usable temperature, microheaters need to be supported or enclosed with very high thermal-resistant ceramic materials often made from small grain, high purity aluminum oxide.

Other potential uses include:
 Fuel Cell Heat Sources,
 Electronics and Substrate Heating,
 RF Applications,
 Micro tube-heaters for small volume gas heating,
 High Power micro-furnace with optional tube extension,
 Fiber optics,
 Ideal for long aspect ratio/very small diameter pieces,
 Fiber optic use to reduce diameter of fibers,
 Igniter,
 MicroPlate heaters,
 Material Testing and Characterization,
 Thermal Property Measurements,
 Diamond Anvil Cells,
 SEM/TEM/AFM,
 Gas/Vapor Heaters/Converters,
 Thin Film Preparation,

When microheaters need controls it is important to heat only electrically, so that power may be controlled by a feed-back mechanism.  New superheated steam or gas spot heaters are coming into use for spot microheater applications.

References 

Heaters
Nails (1979 film). Nails is a 1979 Canadian short documentary film directed by Phillip Borsos. It was nominated for an Academy Award for Best Documentary Short,  and was named Best Theatrical Short in 1980 at the 1st Genie Awards.

Synopsis 
A blacksmith is seen labouring at his forge, shaping nails from single strands of steel rods. The scene shifts from this peaceful setting to the roar of a 20th-century nail mill, where banks of machines draw, cut and pound the steel rods faster than the eye can follow.

References

External links

1979 films
1979 short documentary films
Canadian short documentary films
English-language Canadian films
Documentary films about technology
Films directed by Phillip Borsos
Films without speech
National Film Board of Canada documentaries
National Film Board of Canada short films
Best Theatrical Short Film Genie Award winners
Nail (fastener)
1970s English-language films
1970s Canadian films
English-language short documentary films
Ondra. Ondra may refer to:

Adam Ondra (born 1993), Czech rock climber
Anny Ondra (1903–1987), Czech film actress
Jiří Ondra (born 1957), Czech soccer player
Óndra Łysohorsky (1905-1989), Czech poet
Tesla ONDRA, home computer from 1985 developed in Elstroj, produced by Tesla Liberec and later Tesla Blatna
LNWR Class A. The London and North Western Railway (LNWR) Class A was a class of 0-8-0 steam locomotives.  From 1893 to 1900, Crewe Works built 111 of these engines, which had a three-cylinder compound arrangement, and were designed by Francis Webb. According to the LNWR Society, 110 were built between 1894 and 1900.

Rebuilding
Like the other Webb compounds, they proved problematic, so in 1904 George Whale began rebuilding these to simple expansion engines.  Fifteen were converted to Class C between 1904 and 1906, 62 to Class D between 1906 and 1909, with the remaining 34 rebuilt by Charles Bowen Cooke to Class C1 between 1909 and 1912.

All Class D locomotives were later rebuilt to Class G1. Some of them, rebuilt to Class G2a, were still running in 1962.

Classification
The LNWR letter classification system for 8 coupled engines (A, B, C, etc.) was introduced in 1911.

References

Further reading

 
 

A
0-8-0 locomotives
Compound locomotives
Railway locomotives introduced in 1893
Standard gauge steam locomotives of Great Britain
D n3v locomotives