omniomni/omni-engineering huggingface dataset:
Unit dummy force method. The Unit dummy force method provides a convenient means for computing displacements in structural systems. It is applicable for both linear and non-linear material behaviours as well as for systems subject to environmental effects, and hence more general than Castigliano's second theorem.

Discrete systems
Consider a discrete system such as trusses, beams or frames having members interconnected at the nodes. Let the consistent set of members' deformations be given by , which can be computed using the member flexibility relation. These member deformations give rise to the nodal displacements , which we want to determine.

We start by applying N virtual nodal forces , one for each wanted r, and find the virtual member forces  that are in equilibrium with :

In the case of a statically indeterminate system, matrix B is not unique because the set of  that satisfies nodal equilibrium is infinite. It can be computed as the inverse of the nodal equilibrium matrix of any primary system derived from the original system.

Imagine that internal and external virtual forces undergo, respectively, the real deformations and displacements; the virtual work done can be expressed as:

 External virtual work: 
 Internal virtual work: 

According to the virtual work principle, the two work expressions are equal:

Substitution of (1) gives

Since  contains arbitrary virtual forces, the above equation gives

It is remarkable that the computation in (2) does not involve any integration regardless of the complexity of the systems, and that the result is unique irrespective of the choice of primary system for B. It is thus far more convenient and general than the classical form of the dummy unit load method, which varies with the type of system as well as with the imposed external effects. On the other hand, it is important to note that Eq.(2) is for computing displacements or rotations of the nodes only. This is not a restriction because we can make any point into a node when desired.

Finally, the name unit load arises from the interpretation that the coefficients  in matrix B are the member forces in equilibrium with the unit nodal force , by virtue of Eq.(1).

General systems
For a general system, the unit dummy force method also comes directly from the virtual work principle. Fig.(a) shows a system with known actual deformations . These deformations, supposedly consistent, give rise to displacements throughout the system. For example, a point A has moved to A', and we want to compute the displacement r of A in the direction shown. For this particular purpose, we choose the virtual force system in Fig.(b) which shows:
 The unit force R* is at A and in the direction of r so that the external virtual work done by R* is, noting that the work done by the virtual reactions in (b) is zero because their displacements in (a) are zero:  is the desired displacement
 The internal virtual work done by the virtual stresses is where the virtual stresses  must satisfy equilibrium everywhere.

Equating the two work expressions gives the desired displacement:

Structural analysis
John Engh. John Engh (5 June 1915 – 5 December 1996) was a Norwegian architect, most known for his innovative work in stone and concrete.

Engh was born in New York City. He was the son of Adolf Abel Engh (1884–1941) and Anna Madsine Hald (1888–1972). His father was a Norwegian engineer who was working in the United States at the time of his birth. Engh grew up in Catalonia, Spain, where his father also worked as an engineer.  Engh was educated at ETH Zürich and the Norwegian Institute of Technology where he earned his  diploma in 1938. He had apprenticeships at various architectural firms in Oslo, Barcelona, and Pittsburgh before being hired as an architect with the Royal Norwegian Air Force at CFB Borden in Canada. During the World War II, he served at the Norwegian bases in Canada, where he designed and led development of the Little Norway and Little Skaugum. He also worked for the United States government on reconstruction projects (1943 to 1945).

Upon returning to Scandinavia, he worked for the Scandinavian Airlines System in Stockholm (1945–1946). He later moved to Oslo where he joined in partnership with Peer Qvam (1946–1958). In 1970, he entered into partnership with Jon Seip (Engh og Seip Arkitektkontor A/S). He sat on the board of Norwegian Architects' Association from 1952 to 1968 from 1964 as president. His designs include the Oslo Central Station, HSH headquarters, Indekshuset at Solli plass in Oslo and several other offices buildings. He designed the Norwegian Embassy in Brasília (1984) and acted as local architect for the building of the  American Embassy in Oslo which was designed by Eero Saarinen. He died in Bærum during 1996.

References

1915 births
1996 deaths
ETH Zurich alumni
Norwegian Institute of Technology alumni
Norwegian expatriates in the United States
Norwegian expatriates in Switzerland
Norwegian expatriates in Spain
20th-century Norwegian architects
PKP class EM10. PKP class EM10 is a class of Polish electric locomotives used by the Polish railway operator Polskie Koleje Państwowe (PKP). They were built for shunting purposes.

History
Designed in 1988, the EM10 was intended to function as a shunting locomotive and short distance passenger locomotive. Only four prototypes were built, they were operated by PKP. In 2004, they were modernised by ZNLE Gliwice.

The locomotives last ran in 2009, since then they were stored at the Poznań Franowo depot. In 2021 three were scrapped, one will be offered to a museum or a rolling stock collection.

Locomotive assignment
''

See also
PKP classification system

References

External links
EM10 picture gallery at railfaneurope.net

Bo′Bo′ locomotives
3000 V DC locomotives
EM10
Shunting locomotives
Block (telecommunications). In telecommunications a block is one of:
 A group of bits or digits that is transmitted as a unit and that may be encoded for error-control purposes.
 A string of records, words, or characters, that for technical or logical purposes are treated as a unit. Blocks (a) are separated by interblock gaps, (b) are delimited by an end-of-block signal, and (c) may contain one or more records. A block is usually subjected to some type of block processing, such as multidimensional parity checking, associated with it.

A block transfer attempt is a coordinated sequence of user and telecommunication system activities undertaken to effect transfer of an individual block from a source user to a destination user. 

A block transfer attempt begins when the first bit of the block crosses the functional interface between the source user and the telecommunication system. A block transfer attempt ends either in successful block transfer or in block transfer failure.

Successful block transfer is the transfer of a correct, nonduplicate, user information block between the source user and intended destination user. Successful block transfer occurs when the last bit of the transferred block crosses the functional interface between the telecommunications system and the intended destination user. Successful block transfer can only occur within a defined maximum block transfer time after initiation of a block transfer attempt.

References 
 Federal Standard 1037C
 MIL-STD-188

See also 
 Block (data storage)

Data transmission
C28. C28 or C-28 may refer to:

Vehicles 
 Cessna C-28, an American military transport aircraft
 , a C-class submarine of the Royal Navy
 Sikorsky C-28, an amphibious aircraft bought by the United States Army Air Corps

Other uses 
 C28 road (Namibia)
 Caldwell 28, an open cluster
 Fighting Internet and Wireless Spam Act, an Act of the Parliament of Canada introduced as Bill C-28
 C28 Music, an experimental electronic music artist
Multiagency Coordination Systems. Multi-agency Coordination Systems (MACS) are a part of the United States standardized Incident Command System.
MACS provides the basic architecture for facilitating the allocation of resources, incident prioritization, coordination and integration of multiple agencies for large-scale incidents and emergencies.

Functions and responsibilities
The principal functions and responsibilities of MAC entities typically include the following:
Ensuring that each agency involved in incident management activities is providing appropriate situational awareness and resource status information;
Establishing priorities between incidents and/or Area Commands in concert with Incident Commanders or a Unified Command;
Acquiring and allocating resources required by incident management personnel in concert with the priorities established by Incident or Unified Command;
Anticipating and identifying future resource requirements;
Coordinating and resolving policy issues arising from the incident(s); and
Providing strategic coordination as required.

See also
 Multi-agency coordination

References

Incident management
Addams Stratton McAllister. Addams Stratton McAllister (February 24, 1875 – November 26, 1946) was an American  electrical engineer and editor.

Career 
He was educated at Pennsylvania State College (B.S. 1898; E.E., 1900) and at Cornell University (M.M.E., 1901; Ph.D., 1905).

He was employed by the Berwind-White Coal Mining Company in 1898 and by the Westinghouse Electric and Manufacturing Company in 1899.  He was associate editor (1905–12) and thereafter editor of the Electrical World.  He contributed many articles on engineering subjects to technical publications. In 1915, he was president of the Illuminating Engineering Society.

In 1921 he joined the Bureau of Standards as a liaison officer, progressing in 1926 to head the Division of Specifications and to Assistant Director in 1929. The bureau's Standards Yearbooks from 1927 to 1933 were published under his direction. He retired in February 1945.

He was inducted as a Fellow of the American Physical Society in 1929.

Bibliography

Books 

 Alternating Current Motors (1906; third edition, 1909) McGraw-Hill Book Co; Enlarged. 
 Standard Handbook for Electrical Engineers (1907)
 The Descendants of John Thomson, Pioneer Scotch Covenanter (2018) Forgotten Books

References 

1875 births
1946 deaths
Engineers from Virginia
American science writers
Cornell University College of Engineering alumni
People from Covington, Virginia
Penn State College of Engineering alumni
Fellows of the American Physical Society
Lomer–Cottrell junction. 

Lomer-Cottrell Junction
In materials science, a Lomer–Cottrell junction is a particular configuration of dislocations that forms when two perfect dislocations interact on interacting slip planes in a crystalline material.

Formation Mechanism

When two perfect dislocations encounter along a slip plane, each perfect dislocation can split into two Shockley partial dislocations: a leading dislocation and a trailing dislocation. When the two leading Shockley partials combine, they form a separate dislocation with a burgers vector that is not in the slip plane. This is the Lomer–Cottrell dislocation. It is sessile and immobile in the slip plane, acting as a barrier against other dislocations in the plane. The trailing dislocations pile up behind the Lomer–Cottrell dislocation, and an ever greater force is required to push additional dislocations into the pile-up.

Example in FCC Crystals
For an FCC crystal with slip planes of the form {111}, consider the following reactions:

              |leading| |trailing|
 Dissociation of dislocations:

 Combination of leading dislocations:

The resulting dislocation lies along a crystal direction that is not a slip plane at room temperature in FCC materials. This configuration contributes to immobility of the Lomer-Cottrell junction.

Significance
The sessile nature of the Lomer–Cottrell dislocation forms a strong barrier to further dislocation motion. Trailing dislocations pile up behind this junction, leading to an increase in the stress required to sustain deformation. This mechanism is a key contributor to work hardening in ductile materials like aluminum and copper.

References

Crystallographic defects
École pour l'informatique et les techniques avancées. The École Pour l'Informatique et les Techniques Avancées (), more commonly known as EPITA, is a private French grande école specialized in the field of computer science and software engineering created in 1984 by Patrice Dumoucel. It is a private engineering school, member of IONIS Education Group since 1994, accredited by the Commission des titres d'ingénieur (CTI) to deliver the French Diplôme d'Ingénieur, and based at Le Kremlin-Bicêtre south of Paris.

In June 2013, EPITA becomes member of the Union of Independent Grandes Écoles, which includes 30 grandes écoles.

The school is part of IONIS Education Group.

Studies

French Stream

Preparatory class 

The first two years of studies are preparatory years. During these two years, students study mathematics, physics and electronics as well as algorithmics and computer science.

Engineering class

The first year 

The third year is the first year of engineering studies, where students learn the fundamentals in information technology and software engineering. This year is also famous for its first month, during which students will be asked to make several projects, which generally lead them to code more than 15 hours per day. Third year students are known to say that "sleeping is cheating" and usually remember this year as their most painstaking year at EPITA.

Majors 

During the fourth and fifth years students have to choose one of the nine majors:

 IMAGE, Traitement et synthèse d'image ("Image processing and synthesis")
 SRS, Systèmes, Réseaux et Sécurité ("Systems, Networks and Security")
 MTI, Multimédia et Technologies de l'Information ("Multimedia and Information Technology")
 SCIA, Sciences Cognitives et Informatique Avancée ("Cognitive Science and Advanced Computer Science")
 QUANTUM, Quantum Computing & Quantum Technologies ("Quantum")
 SANTÉ, Data science généraliste (General data science)
 GISTRE, Génie Informatique des Systèmes Temps Réel et Embarqués ("Computer Engineering, Real-time Systems and Embedded System")
 SIGL, Systèmes d’Information et Génie Logiciel ("Information Systems and Software Engineering")
 TCOM, Télécommunications ("Telecommunication")
 GITM, Global IT Management (Entirely taught in English)
RECHERCHE, (Majeure double compétence orientée vers la recherche académique)

References

External links 

  Official website

Educational institutions established in 1984
Education in Île-de-France
Education in Lyon
Education in Rennes
Education in Toulouse
Education in Strasbourg
Grandes écoles
1984 establishments in France
FCAS. FCAS may refer to:

 Familial cold autoinflammatory syndrome, a genetic disease
 Fellow of the Casualty Actuarial Society, a U.S. professional society
 The Foundation to Combat Antisemitism, a philanthropic effort by Robert Kraft
 Frequency Control Ancillary Services for electric power grids
 Future Combat Air System, a sixth-generation fighter jet currently in development by France, Germany, and Spain
 Future Combat Air System (UK), a sixth-generation fighter jet, the BAE Systems Tempest, and related technologies currently under development by the United Kingdom, Italy and Sweden.
 FCA Serbia
Rheinmetall KZO. KZO (Kleinflugzeug für Zielortung, German for small aircraft for target acquisition) is an unmanned aerial vehicle (UAV) with stealth characteristics manufactured by Airbus Defence and Space Airborne Solutions GmbH of Germany. Airbus Defence and Space Airborne Solutions GmbH is a joint venture of Airbus Defence and Space and Rheinmetall.

A KZO system consists of 10 UAVs and 2 ground units, consisting of one control station, one radio, one launch, one maintenance vehicle with a refuelling facility for the UAVs and one recovery vehicle.

The UAV is launched with a booster rocket directly out of its container. Landing is done with a parachute.

The KZO's main objective is to locate mobile threats and provide target locations for artillery. KZO replaced the German Army's other main UAV, Drohne CL 289.

The Taifun attack drone was a concept of an armed variant fitted with an intelligent millimeter-wave radar seeker that perform search and destroy attacks autonomously. It destroys its target with a hollow-charge warhead. However, the German Army decided against this concept in favor of the IAI Harop.

Two electronic warfare variants have also been developed as the Mücke ("mosquito") and the Fledermaus ("bat").

The initial system has been sold to China.

Features
 Wingspan: 3.42m
 Length: 2.28m
 Body diameter: 0.36m
 Noise-reduced two-stroke engine driving 2 blade propeller
 Cruise speed: 220 km/h
 Endurance: 4 hours
 Sensor: stabilized forward looking infrared
 Digital data recorder for 10 minutes of video data
 Real-time datalink
 Navigation: inertial, location via datalink, additionally GPS (not needed for operation)
 Reduced visual, acoustic, radar and infrared signature (stealth technology)

References

  @ Airbus Defence and Space

KZO
Unmanned military aircraft of Germany
General Electric J31. The General Electric J31 was the first jet engine to be mass-produced in the United States.

Design and development

After a visit to England mid-1941, General Henry H. Arnold was so impressed by flight demonstrations of the Gloster E.28/39 jet aircraft he had witnessed that he arranged for the Power Jets W.1X turbojet engine to be shipped by air to the U.S, along with drawings for the more powerful W.2B/23 engine, so that the US could develop its own jet engine.

General Electric's extensive experience in turbocharger production made them the natural choice for producing such an engine. The initial prototype, the General Electric I-A, was essentially based on the W.2B/23. It first ran on 18 April 1942 and developed a static thrust of 1250lbf.

The I-A air intake consisted of two peripheral slots which led  to a double-sided, centrifugal compressor. A series of vanes guided the air into the impeller eyes. After radial compression, the air was diffused and turned 90 degrees rearwards, before entering a set of ten reverse-flow combustion chambers (i.e. cans). A relatively short shaft connected the compression system to the single stage axial turbine. After expansion through the turbine, the combustion products exhausted the engine through the simple conical propelling nozzle, via the jet-pipe. For the turbine section, GE used a proprietary metal developed for their turbochargers, Hastelloy B.

Using their turbocharger expertise, General Electric were able to, in a short space of time, develop a -thrust version, known as the I-14. Later they increased the thrust to . This version was referred to internally as the I-16 However, the United States Army Air Forces later decided to standardize all their jet engine naming, at which point the I-16 became the J31.

Production of the J31 started for the P-59 Airacomet in 1943, and by the time the lines shut down in 1945, a total of 241 had been built. GE also used the basic design to produce the much larger I-40 with 4,000 lbf, but this design was passed on to Allison as the J33. Another derivative of the J31, the General Electric I-20, given the military designation J39, was ordered but later cancelled.

Meanwhile, the British version of the W.2B/23 turbojet entered production as the 1,600lbf thrust Rolls-Royce Welland 1 in October, 1943. The Gloster Meteor I fighter, which entered RAF service in July, 1944, was powered by the Welland I.

Applications
 Bell P-59 Airacomet
 Ryan FR Fireball
 Ryan XF2R Dark Shark

Surviving engines

 There is a J31 on display at the New England Air Museum, Bradley International Airport, Windsor Locks, Connecticut
 There is a J31 on display at the Hickory Aviation Museum, Hickory Regional Airport, Hickory, North Carolina

Specifications (J31)

See also

References

 
 

J31
1940s turbojet engines
Centrifugal-flow turbojet engines
John Alexander Hopps. John Alexander Hopps,  (May 21, 1919 – November 24, 1998) was a co-developer of both the first artificial pacemaker and the first combined pacemaker-defibrillator, and was the founder of the Canadian Medical and Biological Engineering Society (CMBES). He has been called the "Father of biomedical engineering in Canada."

He was also the President and Secretary-General of the International Federation for Medical and Biological Engineering from the 1970s to the mid-1980s. He is a member of the Canadian Science and Engineering Hall of Fame.

Life and work 
Born in Winnipeg, Manitoba, he received a B.Sc.Engineering degree in electrical engineering from the University of Manitoba in 1941. He joined the National Research Council of Canada (NRC) in 1942.

In the early 1940s, Hopps was very focused on researching how to pasteurize beer using various waves like radio waves or microwaves. Beginning in 1949, he worked with Doctors Wilfred Bigelow and John Callaghan at the Banting Institute in the University of Toronto, developing the world's first external artificial pacemaker in 1951. (The first internal pacemaker was implanted in a human body by a Swedish team in 1958.) Hopps initially resented his work at the institute, calling it "an annoying interruption." During this work, Hopps discovered that the heart would contract when subjected to electrical impulses.

Hopps was an advisor to the Sri Lanka health department's Electromedical Division through the Canadian government's Colombo Plan in 1957-58 before returning to the NRC and becoming head of its Medical Engineering Section in 1973.

In 1965, Hopps founded the Canadian Medical and Biological Engineering Society (CMBES) and became its first President. In 1971, he was appointed president of the International Federation for Medical and Biological Engineering, for which he later served as the secretary general from 1976 to 1985. In 1976, he was awarded the honour of Fellow of the CMBES. He was also the President of the Ontario Heart Foundation's Ottawa Chapter.

He retired in 1978. In 1985, his autobiography, Passing Pulses, the Pacemaker and Medical Engineering: A Canadian Story, was published. The same year, he also won the A.G.L. McNaughton Award for engineering contributions made as a Canadian.

In 1986, he was made an Officer of the Order of Canada.

References

Sources

  
 
 

1919 births
1998 deaths
20th-century Canadian inventors
Canadian medical researchers
Canadian electrical engineers
Officers of the Order of Canada
People from Winnipeg
Scientists from Manitoba
University of Manitoba alumni
University of Toronto people