omniomni/omni-engineering huggingface dataset:
Compressive stress. Compressive stresses are generated in objects when they are subjected to forces that push inward, causing the material to shorten or compress. These stresses occur when an object is squeezed or pressed from opposite directions. In everyday life, compressive stresses are common in many structures and materials. For instance, the weight of a building creates compressive stresses in its walls and foundations. Similarly, when a person stands, the bones in their legs experience compressive stresses due to the weight of the body pushing down. Compressive stresses can lead to deformation if they are strong enough, potentially causing the object to change shape or, in extreme cases, to break. The ability of a material to withstand compressive stresses without failing is known as its compressive strength.

When an object is subjected to a force in a single direction (referred to as a uniaxial compression), the compressive stress is determined by dividing the applied force by the cross-sectional area of the object. Consequently, compressive stress is expressed in units of force per unit area.

Thus, the formula for compressive stress is,Where: 

σ is the compressive stress, 

F is the force applied on the object, and 

A is its cross-sectional area. 

As shown in the formula above, compressive stress is typically represented by negative values to indicate that there is compression of an object, however, in geotechnical engineering compressive stress is conventionally represented by positive values. 

Failure of a loaded object occurs when the compressive stress reaches or exceeds its compressive strength. However, in long slender elements, such as columns or truss bars, it can occur at a lower stress because of buckling.

References 

Materials science
William Sturgeon. William Sturgeon (; 22 May 1783 – 4 December 1850) was an English electrical engineer and inventor who made the first electromagnet and the first practical electric motor.

Early life 
Sturgeon was born on 22 May 1783 in Whittington, near Carnforth, Lancashire, and became apprenticed to a shoemaker.

Career
Sturgeon joined the army in 1802 and taught himself mathematics and physics. In 1824 he became lecturer in Science and Philosophy at the East India Company's Military Seminary at Addiscombe, Surrey, and in the following year he exhibited his first electromagnet. He displayed its power by lifting nine pounds with a seven-ounce piece of iron wrapped with wire through which a current from a single battery was sent.

In 1832 he was appointed to the lecturing staff of the Adelaide Gallery of Practical Science in London, where he first demonstrated the DC electric motor incorporating a commutator.

In 1836 he established the journal Annals of Electricity, Magnetism and Chemistry, and in the same year he invented a galvanometer.

Sturgeon was a close associate of John Peter Gassiot and Charles Vincent Walker, and the three were instrumental in founding the London Electrical Society in 1837.

In 1840 he became superintendent of the Royal Victoria Gallery of Practical Science in Manchester. He formed a close social circle with John Davies, one of the Gallery's promoters, and Davies's student James Prescott Joule, a circle that eventually extended to include Edward William Binney and the surgeon John Leigh. The Gallery closed in 1842, and he earned a living by lecturing and demonstrating.

In 1843 he started the monthly journal, The Annals of Philosophical Discovery and Monthly Reporter of the Progress of Practical Science; issue 1 of volume 1 is dated July 1843. Each month's issue contains a mixture of original "long" papers (over 5 pages long), republished papers from foreign journals (translated where necessary) and shorter articles. However, the journal did not prove successful, and ceased publication at the end of volume 1, in December 1843. This single volume is archived at Internet.org.

Death and burial
Sturgeon died in Prestwich, Lancashire (now in Greater Manchester) on 4 December 1850. He is buried there, in the churchyard of the St Mary the Virgin: he is identified on his grave slab as "William Sturgeon – The Electrician".

References

Bibliography 

1783 births
1850 deaths
English inventors
People of the Industrial Revolution
English physicists
People from Carnforth
British East India Company people
Elka 22. The Elka 22 was the second Bulgarian electronic calculator produced by ELKA; it was  released in 1966 and its serial production began in 1967 in the town of Silistra.  Weighing 8.5 kilograms (18.7 pounds), the Elka 22 has 3 registers and operates with 12 decimal digits. Addition speed is 0.3 seconds per operation, and division speed is 0.5 seconds.  Its power consumption is 35 watts. This calculator has a plastic case, a nixie tube display and its technology is based on numerous phenol boards populated with hundreds of discrete transistors, diodes and resistors, not unlike other calculator models developed around the mid-1960s. The machine used a magnetic-core memory.

References 

Electronic calculators by company
Goods manufactured in Bulgaria
History of Silistra
Media gateway. A media gateway is a translation device or service that converts media streams between disparate telecommunications technologies such as POTS, SS7, Next Generation Networks (2G, 2.5G and 3G radio access networks) or private branch exchange (PBX) systems. Media gateways enable multimedia communications across packet networks using transport protocols such as Asynchronous Transfer Mode (ATM) and Internet Protocol (IP).

Because the media gateway connects different types of networks, one of its main functions is to convert between different transmission and coding techniques. Media streaming functions such as echo cancellation, DTMF, and tone sender are also located in the media gateway.

Media gateways are often controlled by a separate Media Gateway Controller which provides the call control and signaling functionality. Communication between media gateways and Call Agents is achieved by means of protocols such as MGCP or Megaco (H.248) or Session Initiation Protocol (SIP). Modern media gateways used with SIP are often stand-alone units with their own call and signaling control integrated and can function as independent, intelligent SIP end-points.

Voice over Internet Protocol (VoIP) media gateways perform the conversion between Time-division multiplexing (TDM) voice to a media streaming protocol, such as the Real-time Transport Protocol, (RTP), as well as a signaling protocol used in the VoIP system.

Mobile access media gateways connect the radio access networks of a public land mobile network PLMN to a next-generation core network. 3GPP standards define the functionality of CS-MGW and IMS-MGW for UTRAN and GERAN based PLMNs.

See also
 Signaling gateway

References

Telecommunications equipment
David P. Reed. David Patrick Reed (born January 31, 1952) is an American computer scientist, educated at the Massachusetts Institute of Technology, known for a number of significant contributions to computer networking and wireless communications networks.

He was involved in the early development of TCP/IP, and was the designer of the User Datagram Protocol (UDP), though he finds this title "a little embarrassing". He was also one of the authors of the original paper about the end-to-end principle, End-to-end arguments in system design, published in 1984.

He is also known for Reed's law, his assertion that the utility of large networks, particularly social networks, can scale exponentially with the size of the network.

From 2003–2010, Reed was an adjunct professor at the MIT Media Lab, where he co-led the Viral Communications group and the Communication Futures program. He currently serves as a senior vice president of the Chief Scientist Group at SAP Labs.

He is one of six principal architects of the Croquet project (along with Alan Kay, Julian Lombardi, Andreas Raab, David A. Smith, and Mark McCahill). He is also on the advisory board of TTI/Vanguard.

His 1978 dissertation introduced multiversion concurrency control  (MVCC). MVCC is a concurrency control method commonly used by database management systems to provide concurrent access to the database and in programming languages to implement transactional memory.

References

External links
 
 Reed's Locus
 Biography
 Naming and synchronization in a decentralized computer system (Reed's thesis, 1978)

Living people
American computer scientists
MIT School of Architecture and Planning faculty
Massachusetts Institute of Technology alumni
1952 births
MIT Media Lab people
USS Wright. USS Wright may refer to:

, was launched in 1920 as airship tender AZ-1, then converted twice more during her career for various duties until 1946 when she was scrapped
Wright (CV-47), was an Essex-class carrier laid down in August 1944 and renamed  in February 1945, prior to launching
 was a light aircraft carrier commissioned in 1947, converted to a command ship and recommissioned as CC-2 in 1962, and decommissioned in 1970
 is an active Aviation Logistics Support (Roll-on/Roll-off) container ship used by the US Navy Auxiliary

United States Navy ship names
HC. HC, hc or H/C may refer to:

Science, technology, and mathematics

Medicine 
 Health Canada
 Hemicrania continua
 Hyperelastosis cutis or hereditary equine regional dermal asthenia

Chemistry 
 Hemocyanin, a metalloprotein abbreviated Hc
 HC smoke, a US military designation for Hexachloroethane
 Homocapsaicin, a capsaicinoid
Hydrocarbon, a category of substances consisting only of hydrogen and carbon

Other uses in science, technology, and mathematics
 74HC-series integrated circuits, a logic family of integrated circuits
 Felix HC, a series of Romanian personal microcomputers produced by ICE Felix Bucharest and which were ZX Spectrum clones
 Hemianthus callitrichoides, a freshwater aquatic plant native to Cuba
 + h.c., a notation used in mathematics and quantum physics

Sports 
 Head Coach
 Hors catégorie (French), used in cycle races to designate a climb that is "beyond categorization"
 UCI .HC road cycling races (1.HC and 2.HC), the second tier of events in the sport, after the UCI World Tour

Other uses 
 Heritage Corridor, a Metra commuter rail line running from Chicago to Joliet, Illinois
 Highway contract route, an outsourced United States Postal Service delivery method, formerly known as Star routes
 Honorary degree, or honoris causa
 Hors de commerce, prints similar to Artist Proofs except they are only available through the artist directly
 Hospitality Club, an internet-based hospitality service
 Houston Chronicle, newspaper of record of Houston, Texas
 Aero-Tropics Air Services (IATA airline designator HC)
 Disability, acronym for Handicap/Handicapped 
 High-cube container, a type of intermodal shipping container
Festival Speech Synthesis System. The Festival Speech Synthesis System is a general multi-lingual speech synthesis system originally developed by Alan W. Black, Paul Taylor and Richard Caley at the Centre for Speech Technology Research (CSTR) at the University of Edinburgh. Substantial contributions have also been provided by Carnegie Mellon University and other sites. It is distributed under a free software license similar to the BSD License.

It offers a full text to speech system with various APIs, as well as an environment for development and research of speech synthesis techniques. It is written in C++ with a Scheme-like command interpreter for general customization and extension.

Festival is designed to support multiple languages, and comes with support for English (British and American pronunciation), Welsh, and Spanish. Voice packages exist for several other languages, such as Castilian Spanish, Czech, Finnish, Hindi, Italian, Marathi, Polish, Russian and Telugu.

Festvox
The Festvox project aims to make the building of new synthetic voices more systematic and better documented, making it possible for anyone to build a new voice. It is distributed under a free software license similar to the MIT License.

Festvox is a suite of tools by Alan W. Black and Kevin Lenzo for building synthetic voices for Festival. It includes a step-by-step tutorial with examples in document called "Building Synthetic Voices".

Flite
Flite is a small run-time speech synthesis engine developed at Carnegie Mellon University, derived from both Festival and Festvox.

Linux compatibility
There is a Festival plug-in for GStreamer. Festival is pre-packaged for several Linux distributions.

See also
 Orca (assistive technology)

References

External links

 The Festival Speech Synthesis System
 Flite at CMU 
 Festvox
 Flinger singing synthesis 
 Lyricos singing synthesis 

Free speech synthesis software
Free multimedia software
Free software programmed in C++
Spoken articles
Singing software synthesizers
Sidney H. Liebson. Sidney H. Liebson (July 9, 1920 – February 7, 2017) received his Ph.D. from the University of Maryland in 1947. His thesis was on the discharge mechanism of Geiger–Müller counters. Liebson received a US Navy award for developing the first equipment used to identify enemy radar.

Liebson participated in atomic bomb testing in the Pacific, developing radiation detectors that were used to measure bomb characteristics. In a significant test, his detectors validated the feasibility of making the hydrogen bomb. At a time when electronics had not been able to make measurements with nanosecond accuracy, he developed several techniques to accomplish this accuracy for measuring organic fluorescence decay times and organic scintillation pulse widths by indirect means.

His 1947 invention of the use of halogen gas in Geiger–Müller tubes led to considerable benefits in reducing the voltage of operation and greatly extended the life of the tubes. All modern GM tubes use his halogen-based quench gas.  This innovation occurred while he was working on his thesis.
Liebson died on February 7, 2017.

References

1920 births
2017 deaths
University of Maryland, College Park alumni
American scientists
Fellows of the American Physical Society
Earthworks. Earthworks may refer to:

Construction
Earthworks (archaeology), human-made constructions that modify the land contour
Earthworks (engineering), civil engineering works created by moving or processing quantities of soil
Earthworks (military), military fortifications built in the field during a campaign or siege

Arts and media
Earthworks (novel), a novel by Brian Aldiss
Earthworks (band), a jazz band led by drummer Bill Bruford
Earthworks (album), the band's self-titled debut album
"Earthworks" (song), a 1993 song by Kerbdog
Land art or Earth art

Other uses
Earthworks (company), an audio equipment company
Earthworks High School, an experimental school in Ann Arbor, Michigan
Actor (UML). An actor
in the Unified Modeling Language (UML) "specifies a role played by a user or any other system that interacts with the subject."

"An Actor models a type of role played by an entity that interacts with the subject (e.g., by exchanging signals and data),
but which is external to the subject."

"Actors may represent roles played by human users, external hardware, or other subjects. Actors do not necessarily represent specific physical entities but merely particular facets (i.e., “roles”) of some entities that are relevant to the specification of its associated use cases. A single physical instance may play the role of several different actors and a given actor may be played by multiple different instances."

UML 2 does not permit associations between Actors. The use of generalization/specialization relationship between actors is useful in modeling overlapping behaviours between actors and does not violate this constraint since a generalization relation is not a type of association.

Actors interact with use cases.

References

External links
 Illustration of actors in UML

 Current UML specification: 

Unified Modeling Language
George Hersee. George Hersee (29 December 1924 – 11 April 2001) was a BBC engineer, who is most famous for his development of Test Card F. This design came about after Hersee was asked to intervene by the committee charged with the creation of technical standards for the new colour TV services.

Hersee was born in Sussex, England. He was educated at Chichester Boys School and attended the University of Southampton, where he studied electrical engineering. In 1949, he joined the BBC's Planning & Installation Department, which equipped the BBC studios. By the late 1950s, he was specialising in lens and test card transparency specifications and became one of the leaders in this new field. 

The BBC had first begun to use television test cards in the 1930s, and by the mid 1960s it was realised that a new colour card was required, with particular attention being paid to the accuracy of skin tones. Hersee's now-iconic Test Card F from 1967 features a photograph of Carole, his eldest daughter, to meet that requirement.

Hersee published a monograph in 1967 entitled "A Survey of the Development of Television Test Cards Used in the BBC", but left the BBC in 1979 to work for a private engineering company.

He died at age 76, and was survived by his wife and two daughters, Carole and Gillian.

See also
Test Card J
Test Card W
Test card
List of BBC test cards
Bubbles the Clown

References

External links
University of Southampton magazine
Test card special
Carole Hersee interview - 40th anniversary of test card F
 The Story of Carole Hersee - The BBC Test Card Girl (documentary on Youtube)

1924 births
2001 deaths
Alumni of the University of Southampton
People from West Sussex
English engineers
User equipment. In the Universal Mobile Telecommunications System (UMTS) and 3GPP Long Term Evolution (LTE), user equipment (UE) is any device used directly by an end-user to communicate. It can be a hand-held telephone, a laptop computer equipped with a mobile broadband adapter, or any other device. It connects to the base station Node B/eNodeB as specified in the ETSI 125/136-series and 3GPP 25/36-series of specifications.  It roughly corresponds to the mobile station (MS) in GSM systems.

The radio interface between the UE and the Node B is called Uu. In the context of UMTS (Universal Mobile Telecommunications System), Uu stands for the interface between UTRAN (UMTS Terrestrial Radio Access Network) and the UE (User Equipment).

Functionality 
UE handles the following tasks towards the core network:
 Mobility management
 Call control
 Session management
 Identity management

The corresponding protocols are transmitted transparently via a Node B, that is, Node B does not change, use or understand the information. These protocols are also referred to as Non Access Stratum protocols.

The UE is a device which initiates all the calls and it is the terminal device in a network.

References

External links 

 3GPP 25-series of specifications
 3GPP 36-series of specifications

 
UMTS
Mobile telecommunications standards
3GPP standards
Conchoidal fracture. A conchoidal fracture is a break or fracture of a brittle material that does not follow any natural planes of separation. Mindat.org defines conchoidal fracture as follows: "a fracture with smooth, curved surfaces, typically slightly concave, showing concentric undulations resembling the lines of growth of a shell". Materials that break in this way include quartz, chert, flint, quartzite, jasper, and other fine-grained or amorphous materials with a composition of pure silica, such as obsidian and window glass, as well as a few metals, such as solid gallium.

Crystalline materials such as quartz also exhibit conchoidal fractures when they lack a cleavage plane and do not break along a plane parallel to their crystalline faces. So, a conchoidal, or uneven fracture is not a specific indication of the amorphous character of a mineral, or a material. Amorphous, cryptocrystalline, and crystalline materials can all present conchoidal fracture when they lack a preferential cleavage plane.

Conchoidal fractures can occur in various materials if they are properly percussed (struck). Cryptocrystalline silica, such as chert, or flint, with this material property were widely sought after, traded, and fashioned into sharp tools in the Stone Age.

Conchoidal fractures often result in a curved breakage surface that resembles the rippling, gradual curves of a mussel shell; the word "conchoid" is derived from the word for this animal ( konchoeidēs <  konchē). A swelling appears at the point of impact called the bulb of percussion. Shock waves emanating outwards from this point leave their mark on the stone as ripples. Other conchoidal features include small fissures emanating from the bulb of percussion.

They are defined in contrast to the faceted fractures often seen in single crystals such as semiconductor wafers and gemstones and to the high-energy ductile fracture surfaces desirable in most structural applications.

Subsets
Several subdefinitions exist, for instance on the Webmineral website:

 Brittle—conchoidal: very brittle fracture producing small, conchoidal fragments
 Brittle—subconchoidal: brittle fracture with subconchoidal fragments
 Conchoidal—irregular: irregular fracture producing small, conchoidal fragments
 Conchoidal—uneven: uneven fracture producing small, conchoidal fragments
 Subconchoidal: fractures developed in brittle materials characterized by semi-curving surfaces

Lithics
In lithic stone tools, conchoidal fractures form the basis of flint knapping, since the shape of the broken surface is controlled only by the stresses applied, and not by some preferred orientation of the material. This property also makes such fractures useful in engineering, since they provide a permanent record of the stress state at the time of failure. As conchoidal fractures can be produced only by mechanical impact, rather than frost cracking for example, they can be a useful method of differentiating prehistoric stone tools from natural stones.

See also

 Fracture (mineralogy)

References

External links

 

Lithics
Materials degradation
Mineralogy concepts
Petrology
Stone Age
Nanotube. A nanotube is a nanoscale cylindrical structure with a hollow core, typically composed of carbon atoms, though other materials can also form nanotubes. Carbon nanotubes (CNTs) are the most well-known and widely studied type, consisting of rolled-up sheets of graphene with diameters ranging from about 1 to tens of nanometers and lengths up to millimeters. These structures exhibit remarkable physical, chemical, and electrical properties, including high tensile strength, excellent thermal and electrical conductivity, and unique quantum effects due to their one-dimensional nature. Nanotubes can be classified into two main categories: single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs), each with distinct characteristics and potential applications. Since their discovery in 1991, nanotubes have been the subject of intense research and development, with promising applications in fields such as electronics, materials science, energy storage, and medicine.

Types 
 BCN nanotube, composed of comparable amounts of boron, carbon, and nitrogen atoms
 Boron nitride nanotube, a polymorph of boron nitride
 Carbon nanotube, includes general nanotube terminology and diagrams
 DNA nanotube, a two-dimensional lattice which curves back upon itself, somewhat similar in size and shape to a carbon nanotube
 Gallium nitride nanotube, a nanotube of gallium nitride
 Silicon nanotube, made of silicon atoms
 Non-carbon nanotube, especially tungsten(IV) sulfide nanotubes
 Tunneling nanotube, a tubular membrane connection between cells
 Titanium nanotubes, created by the conversion of the mineral anatase by hydrothermal synthesis

Nanotubes builders 
 Chiraltube. Atomistic builder for any nanotubes with any chirality from any 2D material. 
 TubeASP. For carbon nanotubes.
 Nanotuve Modeler. For carbon nanotubes only.

References