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title: "Dual piping"
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Dual piping is a system of plumbing installations used to supply both potable and reclaimed water to a home or business. Under this system, two completely separate water piping systems are used to deliver water to the user. This system prevents mixing of the two water supplies, which is undesirable, since reclaimed water is usually not intended for human consumption.
In the United States, reclaimed water is distributed in lavender (light purple) pipes, to alert users that the pipes contain non-potable water. Hong Kong has used a dual piping system for toilet flushing with sea water since the 1950s.
According to the El Dorado Irrigation District in California, the average dual-piped home used approximately 0.17 acre-feet (210 m3) of potable water in 2006. The average single family residence with traditional piping using potable water for irrigation as well as for domestic uses used between 0.63 acre-feet (780 m3), higher elevation, and 0.78 acre-feet (960 m3), lower elevation.
== Further reading ==
Tang, S.L., Derek P.T. Yue, Damien C.C. Ku: Engineering and Costs of Dual Water Supply Systems, International Water Supply Association 2007, ISBN 1-84339-132-5

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title: "Dublin Accord"
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The Dublin Accord is an agreement for the international recognition of Engineering Technician qualifications.
In May 2002, the national engineering organisations of Ireland, the United Kingdom, South Africa and Canada signed an agreement mutually recognising the qualifications which underpin the granting of Engineering Technician titles in the four countries. Operation of the Dublin Accord is similar as for the Washington Accord and Sydney Accord.
== Signatories ==
== See also ==
Seoul Accord - computing and information technology
Outcome-based education
Chartered Engineer
Professional Engineer
== References ==
== External links ==
International Engineering Alliance Dublin Accord website

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Dynamic timing analysis is a verification of circuit timing by applying test vectors to the circuit. It is a form of simulation that tests circuit timing in its functional context.
== See also ==
Dynamic timing verification
Static timing analysis
== References ==

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EN 10025 - Hot rolled products of structural steels refers to a set of European standards which specify the technical delivery conditions for hot rolled products of structural steels. The standards consist of the following parts:
EN 10025-1: Part 1: General technical delivery conditions
EN 10025-2: Part 2: Technical delivery conditions for non-alloy structural steels
EN 10025-3: Part 3: Technical delivery conditions for normalized/normalized rolled weldable fine grain structural steels
EN 10025-4: Part 4: Technical delivery conditions for thermomechanical rolled weldable fine grain structural steels
EN 10025-5: Part 5: Technical delivery conditions for structural steels with improved atmospheric corrosion resistance
EN 10025-6: Part 6: Technical delivery conditions for flat products of high yield strength structural steels in the quenched and tempered condition
== Editions ==
EN 10025:2019 (current version)
EN 10025:2005
EN 10025:1990+A1:1993
EN 10025:1990
== See also ==
List of EN standards
European Committee for Standardization
EN 1993 Eurocode 3: Design of steel structures
== External links ==
European Committee for Standardization

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The EN 10034 "Structural steel I and H sections. Tolerances on shape and dimensions" is a European Standard.
The standard is developed by the technical committee ECISS/TC 103 - Structural steels other than reinforcements. The standard specifies tolerances on dimensions and mass of I and H structural steel beams.
== See also ==
I-beam
EN 10024
== References ==

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The EN 10080: Steel for the reinforcement of concrete is a European Standard. This standard is referenced by EN 1992.
This standard specifies general requirements and definitions for performance characteristics of steel reinforcement suitable for welding, which is used for reinforcement of concrete structures, supplied as finished products:
rods, coils (wire rod, wire) and unwound products;
reinforcement meshes automatically welded in factory conditions;
spatial scaffolds.
Steel conforming to this standard has a corrugated, periodically profiled or smooth surface. This standard does not apply to
Steel reinforcement not suitable for welding;
Zinc-plated steel bars;
Epoxy-coated steel bars;
Corrosion-resistant steel bars;
Prestressed steel bars;
Periodically profiled bars;
Further processing such as cutting or cutting and bending.
This standard does not define technical grades. The technical grades shall be determined in accordance with this standard according to the specified values for Re, Agt, Rm/Re, and Re,act/Re,nom (if applicable), fatigue strength (if applicable), flexibility, weldability, bending strength, welded or clamped joint strength (for welded reinforcement mesh or spatial frameworks) and dimensional tolerances.
== See also ==
Eurocode
== References ==

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EN 1063, or CEN 1063, is a security glazing standard created by the European Committee for Standardization for measuring the protective strength of bullet-resistant glass. It is commonly used in conjunction with EN 1522 (Euronorm standard for Bullet Resistance in Windows, Doors, Shutters and Blinds) to form a ballistic classification system by which armored vehicles and structures are tested and rated. A similar classification system primarily used in the United States is NIJ Standard 0108, the U.S. National Institute of Justice's Standard for Ballistic Resistant Protective Materials which includes glass and armor plate.
== Threat Levels ==
The protective strength of a glazed shielding is rated based on the type of munitions, or threat level, it is capable of withstanding. There are 7 main standard threat levels: BR1-BR7 (also written as B1-B7), each corresponding to a different type of small arms fire. Additionally, there are two other threat levels (SG1 & SG2) corresponding to shotgun munitions.
To be given a particular rating, the glazing must stop the bullet for the specified number of strikes, with multiple strikes placed within 120mm of each other in the test sample which dimensions are 500±5mm x 500±5mm.
The glazing should also be shatterproof and produce no spalls after each strike. Lastly, the classification levels are numbered in order of increasing protective strength. Thus any sample complying with the requirements of one class also complies with the requirements of previous classes. However, the SG (shotgun) classes do not necessarily comply with BR classes.
The precise test requirements and bullet types used are as follows:
LB - Lead Bullet
FJ - Full Metal Jacket
FN - Flat Nose
RN - Round Nose
CB - Cone Bullet
PB - Pointed Bullet
SC - Soft Core (lead)
SCP - Soft Core (lead) & Steel Penetrator
HC - Hard core, steel hardness > 63 HRC
== References ==

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The EN 1090 standards are European standards that regulate the fabrication and assembly of steel and aluminium structures and are recognized by the Construction Products Regulation.
EN 1090 comprises three parts:
EN 1090-1: Requirements for conformity assessment for structural components (CE-Marking)
EN 1090-2: Technical requirements for the execution of steel structures
EN 1090-3: Technical requirements for the execution of aluminium structures
EN 1090 replaced the nationally applicable regulations, e.g. in Germany DIN 18800-7 and DIN V 4113-3.
== References ==
Execution class in EN 1090 certification.
== External links ==

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EN 12566 - Small wastewater treatment systems for up to 50 PT refers to a set of European Standards which specify the general requirements for packaged and/or site assembled wastewater treatment plants used for domestic wastewater treatment for up to 50 PT (population total). The standards consist of the following parts:
EN 12566-1: "Part 1: Prefabricated septic tanks" specifies the requirements and test methods for prefabricated septic tank units;
EN 12566-2: "Part 2: Soil infiltration systems" is a code of practice defining design parameters, construction details, installation, and component requirements for in-situ constructed soil infiltration systems and does not specify any treatment requirements;
EN 12566-3: "Part 3: Packaged and/or site assembled domestic wastewater treatment plants" specifies the requirements and test methods used to evaluate packaged wastewater treatment plants which are required to treat sewage to a predetermined standard;
EN 12566-4: "Part 4: Septic tanks assembled in situ from prefabricated kits" is an execution standard specifying pipe sizes, loads, watertightness, marking, and evaluation of conformity for septic tanks assembled in situ from prefabricated kits and ancillary equipment;
EN 12566-5: "Part 5: Pretreated Effluent Filtration systems" is a code of practise giving design parameters, construction details, installation, and component requirements for filtration systems receiving domestic wastewater from septic tanks;
EN 12566-6: "Part 6: Prefabricated treatment units for septic tank effluent" specifies requirements, test methods, and evaluation of conformity for prefabricated secondary treatment units used for the treatment of effluent from septic tanks;
EN 12566-7: "Part 7: Prefabricated tertiary treatment units" specifies requirements, test methods, and evaluation of conformity for a packaged and/or site assembled tertiary treatment unit.
== See also ==
List of EN standards
European Committee for Standardization
== External links ==
European Committee for Standardization
== References ==

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title: "EN 14214"
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EN 14214 is a standard published by the European Committee for Standardization that describes the requirements and test methods for FAME - the most common type of biodiesel.
The technical definition of biodiesel is a fuel suitable for use in compression ignition (diesel) engines that is made of fatty acid monoalkyl esters derived from biologically produced oils or fats including vegetable oils, animal fats and microalgal oils. When biodiesel is produced from these types of oil using methanol fatty acid methyl esters (FAME) are produced. Biodiesel fuels can also be produced using other alcohols, for example using ethanol to produce fatty acid ethyl esters, however these types of biodiesel are not covered by EN 14214 which applies only to methyl esters i.e. biodiesel produced using methanol.
This European Standard exists in three official versions - English, French, German. The current version of the standard was published in November 2008 and supersedes EN 14214:2003.
Differences exist between the national versions of the EN 14214 standard. These differences relate to cold weather requirements and are detailed in the national annex of each standard.
It is broadly based on the earlier German standard DIN 51606. The ASTM and EN standards both recommend very similar methods for the GC based analyses.
Blends are designated as "B" followed by a number indicating the percentage biodiesel. For example: B100 is pure biodiesel. B99 is 99% biodiesel, 1% petrodiesel. B20 is 20% biodiesel and 80% fossil diesel.
== Specifications ==
== See also ==
ASTM D6751 — the standard used in USA and Canada
EN
EN 590
List of EN standards
== References ==
== External links ==
CEN homepage Archived 2007-01-25 at the Wayback Machine
Country specific CFPP requirements according to national annexes of EN 14214

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An ERF damper or electrorheological fluid damper, is a type of quick-response active non-linear damper used in high-sensitivity vibration control.
== References ==

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Eddy current sensors are displacement sensors that use the principle of eddy current formation to sense displacement. These sensors measure shaft displacement in rotating machinery and have been around for many years as they offer manufacturers high-linearity, high-speed measurements, and high resolution. Eddy currents are formed when a moving or changing magnetic field intersects a conductor or vice versa.
The relative motion causes a circulating flow of electrons, or currents, within the conductor. These circulating eddies of current create electromagnets with magnet fields that oppose the effect of applied magnetic field. The stronger the applied magnetic field, or greater the electrical conductivity of the conductor, or greater the relative velocity of motion, the greater the currents developed and greater the opposing field. Eddy current probes senses this formation of secondary fields to find out the distance between the probe and target material.
== References ==

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An electrical drawing is a type of technical drawing that shows information about power, lighting, and communication for an engineering or architectural project. Any electrical working drawing consists of "lines, symbols, dimensions, and notations to accurately convey an engineering's design to the workers, who install the electrical system on the job".
A complete set of working drawings for the average electrical system in large projects usually consists of:
A plot plan showing the building's location and outside electrical wiring
Floor plans showing the location of electrical systems on every floor
Power-riser diagrams showing panel boards.
Single-line diagrams
General arrangement diagrams
Control wiring diagrams
Schedules and other information in combination with construction drawings.
Electrical drafters prepare wiring and layout diagrams used by workers who erect, install, and repair electrical equipment and wiring in communication centers, power plants, electrical distribution systems, and buildings.
== See also ==
One-line diagram
Architectural drawing
Electronic schematic
Engineering drawing
Mechanical drawing
Structural drawing
Working drawing
== References ==

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An electrostatic plotter is a type of plotter that draws images on paper with an electrostatic process. They are most frequently used for Computer-Aided Engineering (CAE), producing raster images via either a liquid toner or a dry toner model.
Liquid toner models use toner that is positively charged and thus becomes attracted to paper's negative charge. This occurs after the toner particles pass through a line of electrodes in the form of tiny wires, or nibs. The spacing of the wires controls the resolution of the plotter; for example, 100 or 400 wires to the inch. Dry toner models use a process similar to xerography in photocopiers. Unlike a laser printer or photocopier, there is no transfer drum used in most electrostatic plotters; the imaging paper is directly exposed to the charging electrode array.
Electrostatic plotters can print in black and white or in color. Some models handle paper sizes up to six feet wide. Newer versions are large-format laser printers and focus light onto a charged drum using lasers or LEDs. The image quality produced by some electrostatic plotters was lower than that of contemporary pen plotters, but the increased speed and economy made them useful. Unlike a pen plotter, the plot time of a rasterized electrostatic plotter was independent of the level of detail of the image. Modern electrostatic color plotters are found in the short run graphics industry, printing on a variety of paper or plastic film surfaces.
Electrostatic plotters were known in the early days of computer graphics; by 1967, several manufacturers commercially supplied electrostatic plotters.
== References ==

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Elegant degradation is a term used in engineering to describe what occurs to machines which are subject to constant, repetitive stress.
Externally, such a machine maintains the same appearance to the user, appearing to function properly. Internally, the machine slowly weakens over time. Unable to withstand the stress, it eventually breaks down. Compared to graceful degradation, the operational quality does not decrease at all, but the breakdown may be just as sudden.
This term's meaning varies depending on context and field, and may not be strictly considered exclusive to engineering. For instance, this is used as a mechanism in the food industry as applied in the degradation of lignin, cellulose, pentosan, and polymers, among others. The concept is also used to extract chemicals such as the elegant degradation of Paederus fuscipes to obtain pederin and hemiacetal pseuodopederin. In this process degradation is induced by heat. A play with the same name also used it as a metaphor for the current state of the world.
== See also ==
Fail safe
Fail soft
== References ==

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An elevator test tower is a structure usually 100 to over 200 metres (300 feet to over 600 feet) tall that is designed to evaluate the stress and fatigue limits of specific elevator cars in a controlled environment. Tests are also carried out in the test tower to ensure reliability and safety in current elevator designs and address any failures that may arise.
Examples of an elevator test tower are the National Lift Tower in Northampton, England; the Solae Tower in Inazawa, Japan; and the TK Elevator Test Tower in Rottweil, Germany (owned by ThyssenKrupp).
== History ==
In 1888, Otis completed an elevator test tower at their factory in Yonkers, New York; this was possibly the first elevator test tower in the United States.
== See also ==
List of elevator test towers
== References ==

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Energy Dome S.p.A. is an Italian company based in Milan that is developing a range of phase-change Carnot battery systems. Their technology is similar to that used in liquid air energy storage systems, but based on carbon dioxide, which cycles between a liquid form in storage containers and gaseous form in sealed inflatable balloon structures in fixed locations. The system uses a Rankine-like cycle, in which a water tank is used to store the thermal energy released during gas liquefaction that will later be used to re-heat the liquid gas to ambient temperature and pressure to drive a turbine to generate electricity.
As of 2025, the company has built a demonstration pilot plant in Sardinia. In 2025, they partnered with Google to develop long-term energy storage systems intended to let Google rely on renewable energy to power their data centers.
A theoretical study shows their system to have a volumetric energy density of 0.17 kWh/m3, with an areal energy storage footprint of 235–250 m2/MWh. Another theoretical study shows the system having an estimated round-trip energy efficiency of 77%.
== References ==
== External links ==
Official website

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The Energy and Environmental Engineering field seeks to conserve and maintain the natural environment by using efficient sources of energy. Energy and environmental engineers are continually searching for solutions to emerging, environment-related issues such as erosion, water disposal, air and water pollution, land resources, human health, and environmental restoration.
Careers in this field focus on improving the built environment, renewable, and traditional energy industries. Industry sectors can range from government, transportation, remediation, waste management, water, sewage, consulting, fossil fuel, construction, and architectural services.
In this field, solar radiation is important and must be understood. Solar radiation affects the Earth's weather and daylight available. This affects not only the Earth's environment but also the smaller internal environments which we create. Energy and environmental engineers acquire knowledge across many disciplines. Energy engineering requires at least an understanding of mechanics, thermodynamics, mathematics, materials, stoichiometry, electrical machines, manufacturing processes and energy systems.
Environmental engineering can be branched into two main areas: internal environments and outdoor environments.
Internal environments may consist of housing or offices or other commercial properties. In this area, the environmental engineering sometimes stands for the designing of building services to condition the internal environment to a comfortable state or the removal of excess pollutants such as carbon dioxide or other harmful substances.
External environments may be water courses, air, land or seas, and may require new strategies for harnessing energy or the creation of treatment facilities for polluting technologies.
This broad degree area covers many areas but is mainly mechanically and electrically biased. It seeks to explore cleaner, more efficient ways of using fossil fuels, while investigating and developing systems using renewable and sustainable resources, such as solar, wind and wave energy.
== References ==

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In a typical power distribution grid, electric transformer power loss typically contributes to about 40-50% of the total transmission and distribution loss. Energy efficient transformers are therefore an important means to reduce transmission and distribution loss. With the improvement of electrical steel (silicon steel) properties, the losses of a transformer in 2010 can be half that of a similar transformer in the 1970s. With new magnetic materials, it is possible to achieve even higher efficiency. The amorphous metal transformer is a modern example.
== References ==
== External links ==
World's largest Amorphous Metal Power Transformer: 99.31% Efficiency [1]
Amorphous Metals in Electric-Power Distribution Applications
Australian MandatoryEfficiency Requirements for Distribution Transformers

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title: "Energy signature"
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In mechanical engineering, energy signatures (also called change-point regression models) relate energy demand of buildings to climatic variables, typically ambient temperature. Also other climatic variables such as heating or cooling degree days are used. In most cases, heating or cooling building energy demand is analysed through energy signatures, but also hot water or electricity demand is considered.
Energy signatures make a simplified assumption of a linear relationship between a building's energy demand and temperature. This assumption allows for balancing accuracy with computation time, as the estimation of energy demand through energy signatures is considerably faster than using building performance simulation software. A crucial advantage of applying energy signatures is that no detailed information on the geometrical, construction, and operational characteristics of buildings needs to be available.
== References ==

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title: "Engine shaft"
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For mine construction, an engine shaft is a mine shaft used for the purpose of pumping, irrespective of the prime mover.
== See also ==
Outline of mining
Shaft sinking
== References ==

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---
An engineering officer can be a Merchant Navy engineer, or a commissioned officer in the British Armed Forces with responsibility for military engineering.
In the Royal Navy (RN), Engineering Officers are responsible for the material condition of ships, submarines, and naval aircraft.
In the Royal Air Force (RAF), Engineering Officers are responsible for weapons and aircraft systems and electronics communications systems.
== References ==

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EngineeringUK is an independent, not-for-profit organization. The engineering and technology sectors in the UK need a stronger, more representative workforce. EngineeringUK with a mission to drive change so more young people choose engineering and technology careers. They work with hundreds of organisations across business, education, government and the engineering community so they can grow the future talent pool. EngineeringUK's purpose is to drive change so more young people choose engineering and technology careers.
Previously known as the Engineering and Technology Board (ETB), EngineeringUK was founded on 14 February 2001. EngineeringUK are part of the National Engineering Policy Centre.
== Activities ==
Their work centres around four areas:
1 Research and evidence: establish the composition of the current engineering and technology workforce, the future workforce needs and how to address them. They look at STEM education pathways as well as young people's attitudes. All evidence is available on their website.
2 Leadership: grow the collective impact of all engineering and technology inspiration and career activities with young people of school age. Members and Professional Engineering Institutions support the collective impact, as do The Tomorrow's Engineers Code community. All engagements, best practices, case studies and resources are free and available across EngineeringUK's websites.
3 Activities for schools: a wide range of activities to encourage more, and more diverse, young people into engineering and technology roles. EngineeringUK run the Big Bang programme of activities, including a national competition and the UK’s largest annual science fair for young people, as well as the Climate Schools Programme – developed to link future skills needs with sustainability. EngineeringUK is the lead organizer of the annual The Big Bang UK Young Scientists & Engineers Fair.
4 Advocacy: address policy and delivery challenges in STEM and careers education and workforce planning for engineering and tech, and support change. EngineeringUK advocates for policy improvements in engineering and tech careers provision, vocational routes into engineering, STEM teacher recruitment and pathways into the sector, particularly apprenticeships and T Levels.
== References ==
== External links ==
www.EngineeringUK.com
"The Engineering and Technology Board, registered charity no. 1089678". Charity Commission for England and Wales.
Tomorrow's Engineers tomorrowsengineers.org.uk
The Tomorrow's Engineers Code code.tomorrowsengineers.org.uk

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An engineering apprenticeship in the United Kingdom is an apprenticeship in mechanical engineering or electrical engineering or aeronautical engineering to train craftsmen, technicians, senior technicians, Incorporated Engineers and Chartered Engineer for vocational oriented work and professional practice. Chartered Engineers are usually formed through a university degree programme at the Masters Engineering level and may undertake a short form of post graduate apprenticeship. A typical example is the apprenticeships formerly available at the British Thomson-Houston and English Electric companies at Rugby in England. Subjects covered included mathematics, engineering sciences, limits and fits, metallurgy, foundry technology, engineering drawing, design, materials science for engineering materials, metalworking by hand, operating machine tools, and basic features of engineering design. Also refer to apprenticeship and the UK and German section. Elite technical apprenticeships (4-6 years long) have been a decades long tradition at UK companies such as BAE Systems, Rolls-Royce Holdings, Bombardier Aerospace (Short Brothers), and Babcock International.
== References ==

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An engineering bill of materials (EBOM) is a type of bill of materials (BOM) reflecting the product as designed by engineering.
The EBOM is not related to modular BOM or configurable BOM (CBOM) concepts, as modular and configurable BOMs are used to reflect selection of items to create saleable end-products.
The EBOM concept aligns to sales BOMs (as sold), service BOMs (as changed based on changes due to field service).
This BOM includes all substitute and alternate part numbers, and includes parts that are contained in drawing notes.
== See also ==
Bill of materials
Configurable BOM (CBOM)
Material requirements planning (MRP)
Manufacturing resource planning (MRP II)
Enterprise resource planning (ERP)
== References ==

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Engineering optimization
is the subject which uses optimization techniques to achieve design goals in engineering. It is sometimes referred to as design optimization.
== Topics ==
structural design (including pressure vessel design and welded beam design)
shape optimization
topology optimization (including airfoils)
inverse optimization (a subset of the inverse problem)
processing planning
product designs
electromagnetic optimization
space mapping
aggressive space mapping
yield-driven design
optimization exploiting surrogates (surrogate model)
== References ==

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Engineering research - as a branch of science, it stands primarily for research that is oriented towards achieving a specific goal that would be useful, while seeking to employ the powerful tools already developed in Engineering as well as in non-Engineering sciences such as Physics, Mathematics, Computer science, Chemistry, Biology, etc. Often, some of the knowledge required to develop such tools is nonexistent or is simply not good enough, and the engineering research takes the form of a non-engineering science. Since engineering is extensive, it comprises specialised areas such as bioengineering, mechanical engineering, chemical engineering, electrical and computer engineering, civil and environmental engineering, agricultural engineering, etc.
The largest professional organisation is the IEEE that today includes much more than the original Electrical and Electronic Engineering.
Major contributors to engineering research around the world include governments, private business,
and academia.
The results of engineering research can emerge in journal articles, at academic conferences, and in the form of new products on the market.
Much engineering research in the United States of America takes place under the aegis of the Department of Defense.
Military-related research into science and technology has led to "dual-use" applications, with the adaptation of weaponry, communications and other defense systems for the military and other applications for civilian use. Programmable digital computers and the Internet which connects them, the GPS satellite network, fiber-optic cable, radar and lasers provide examples.
== See also ==
List of engineering schools
Engineer's degree
Engineering studies
Engineering education research
== References ==

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Engineering science and mechanics (ESM) is a multidisciplinary and interdisciplinary engineering program and/or academic department. It is available at various American universities, including Pennsylvania State University, University of Virginia, Virginia Polytechnic Institute and State University, Georgia Institute of Technology, and University of Alabama.
== Programs ==
A Bachelor of Science, Master of Science, Master of Engineering, or Ph.D. degree in engineering science, engineering mechanics, or engineering science and mechanics is awarded upon completion of the respective program.
Areas of specialization include aerodynamics, biomechanics, bionanotechnology, biosensors and bioelectronics, composite materials, continuum mechanics, data mining, electromagnetics of complex materials, electronic materials and devices, experimental mechanics, fluid mechanics, laser-assisted micromanufacturing, metamaterials, microfabrication, microfluidic systems, microelectromechanical systems (MEMS) and microoptoelectromechanical systems (MOEMS), nanotechnology, neural engineering, non-destructive testing or evaluation, nonlinear dynamics, optoelectronics, photonics and plasmonics, quantum mechanics, solar-energy-harvesting materials, solid mechanics, solid-state physics, structural health monitoring, and thin films and nanostructured materials.
== History ==
In 1972, the department of engineering mechanics at the Virginia Polytechnic Institute and State University changed its name and undergraduate program to engineering science and mechanics. In 1974, the department of engineering mechanics at the Pennsylvania State University merged with engineering science program and the department was renamed to engineering science and mechanics. Engineering science and mechanics is a graduate program in the School of Civil and Environmental Engineering at the Georgia Institute of Technology. The department of aerospace engineering and mechanics at the University of Alabama offers graduate degrees in engineering science and mechanics.
== Academic departments and programs ==
Department of Engineering Science and Mechanics, Pennsylvania State University.
Department of Engineering Science and Mechanics, Virginia Polytechnic Institute and State University.
Graduate Programs in Engineering Science and Mechanics, Georgia Institute of Technology.
Graduate Programs in Engineering Science and Mechanics, University of Alabama.
== See also ==
Applied physics
Applied mechanics
Engineering physics
== References ==
== External links ==
Department of Engineering Science and Mechanics at Pennsylvania State University
Society of Engineering Science Inc.

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Enrei Tunnel (塩嶺トンネル; えんれいトンネル) is a tunnel on the JR's Chuo Main Line in Japan that runs from Okaya, Nagano to Shiojiri, Nagano in Nagano prefecture with approximate length of 5.994 km. It was completed and opened in 1983.
== See also ==
List of tunnels in Japan
Seikan Tunnel Tappi Shakō Line
Sakhalin–Hokkaido Tunnel
Bohai Strait tunnel
== References ==
== External links ==
Gov. maps.gsi.go.jp
Enrei Tunnel
Enrei Tunnel from website: c-nexco.co.jp
Enrei Tunnel (gov. site)

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In engineering, entrainment is the entrapment of one substance by another substance. For example:
The entrapment of liquid droplets or solid particulates in a flowing gas, as with smoke.
The entrapment of gas bubbles or solid particulates in a flowing liquid, as with aeration.
Given two mutually insoluble liquids, the emulsion of droplets of one liquid into the other liquid, as with margarine.
Given two gases, the entrapment of one gas into the other gas.
"Air entrainment" – The intentional entrapment of air bubbles into concrete.
Entrainment defect in metallurgy, as a result of folded pockets of oxide inside the melt.
== See also ==
Souders–Brown equation
== References ==

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An equivalent dumping coefficient is a mathematical coefficient used in the calculation of the energy dispersed when a structure moves. As a civil engineering term, it defines the percent of a cycle of oscillation that is absorbed (converted to heat by friction) for the structure or sub-structure under analysis. Usually it is assumed that the equivalent dumping coefficient is linear, which is to say invariant compare to oscillatory amplitude. Modern seismic studies have shown this not to be a satisfactory assumption for larger civic structures, and have developed sophisticated amplitude and frequency based functions for equivalent dumping coefficient.
When a building moves, the materials it is made from absorb a fraction of the kinetic energy (this is especially true of concrete) due primarily to friction and to viscous or elastomeric resistance which convert motion or kinetic energy to heat.
== References ==

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Ethylenediamine pyrocatechol (EDP), also known as ethylenediamine-pyrocatechol-water (EPW), is an anisotropic etchant solution for silicon. A typical formulation consists of ethylenediamine, pyrocatechol, pyrazine and water. It is carcinogenic and very corrosive. It is mainly used in research labs, and is not used in mainstream semiconductor fabrication processes.
== References ==

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The European Conference on Computer Vision (ECCV) is a biennial research conference with the proceedings published by Springer Science+Business Media. Similar to ICCV in scope and quality, it is held those years which ICCV is not. It is considered to be one of the top conferences in computer vision, alongside CVPR and ICCV,
with an 'A' rating from the Australian Ranking of ICT Conferences and an 'A1' rating from the Brazilian ministry of education. The acceptance rate for ECCV 2010 was 24.4% for posters and 3.3% for oral presentations.
Like other top computer vision conferences, ECCV has tutorial talks, technical sessions, and poster sessions. The conference is usually spread over five to six days with the main technical program occupying three days in the middle, and tutorial and workshops, focused on specific topics, being held in the beginning and at the end.
The ECCV presents the Koenderink Prize annually to recognize fundamental contributions in computer vision.
== Location ==
The conference is usually held in autumn in Europe.
== See also ==
Computer Vision and Pattern Recognition
International Conference on Computer Vision
== References ==

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An event tree is an inductive analytical diagram in which an event is analyzed using Boolean logic to examine a chronological series of subsequent events or consequences. For example, event tree analysis is a major component of nuclear reactor safety engineering.
An event tree displays sequence progression, sequence end states and sequence-specific dependencies across time.
== Analytical tool ==
Event tree analysis is a logical evaluative process which works by tracing forward in time or forwards through a causal chain to model risk. It does not require the premise of a known hazard. An event tree is an inductive investigatory process.
In contrast, the Fault tree analysis (FTA) evaluates risk by tracing backwards in time or backwards through a cause chain. The analysis takes as a premise a given hazard. FTA is a deductive investigatory process.
== Applications ==
An event tree may start from a specific initiator such as loss of critical supply, or component failure.
Some industries use both fault trees and event trees. Software has been created for fault tree analysis and event tree analysis and is licensed for use at the world's nuclear power plants for Probabilistic Safety Assessment.
== See also ==
Event structure
Root cause analysis
Ishikawa diagram
Why-Because analysis
Failure mode and effects analysis (FMEA)
== Notes ==
== References ==
National Research Council (US), Committee on Environmental Impacts Associated with Commercialization of Transgenic Plants, Board on Agriculture and Natural Resources, Division on Earth and Life Studies. (2002). Environmental Effects of Transgenic Plants: the Scope and Adequacy of Regulation. Washington, D.C.: National Academy Press. ISBN 9780309082631; OCLC 231950695
Wang, John X. and Marvin L. Roush. (2000). What Every Engineer Should Know About Risk Engineering and Management. London: CRC Press. ISBN 9781420026962; OCLC 5030452

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Frequency difference of arrival (FDOA) or differential Doppler (DD), is a technique analogous to TDOA for estimating the location of a radio emitter based on observations from other points. (It can also be used for estimating one's own position based on observations of multiple emitters). TDOA and FDOA are sometimes used together to improve location accuracy and the resulting estimates are somewhat independent. By combining TDOA and FDOA measurements, instantaneous geolocation can be performed in two dimensions.
It differs from TDOA in that the FDOA observation points must be in relative motion with respect to each other and the emitter. This relative motion results in different doppler shifts observations of the emitter at each location in general. The relative motion can be achieved by using airborne observations in aircraft, for example. The emitter location can then be estimated with knowledge of the observation points' location and vector velocities and the observed relative doppler shifts between pairs of locations.
A disadvantage of FDOA is that large amounts of data must be moved between observation points or to a central location to do the cross-correlation that is necessary to estimate the doppler shift.
The accuracy of the location estimate is related to the bandwidth of the emitter's signal, the signal-to-noise ratio at each observation point, and the geometry and vector velocities of the emitter and the observation points.
== See also ==
Multilateration
== Further reading ==
Ho, K.C.; Chan, Y.T.;, "Geolocation of a known altitude object from TDOA and FDOA measurements," IEEE Transactions on Aerospace and Electronic Systems, vol.33, no.3, pp.770-783, July 1997. doi:10.1109/7.599239, IEEE XPlore.

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Fellowship of the Institution of Mechanical Engineers (FIMechE) is an award and fellowship granted to individuals that the Institution of Mechanical Engineers judges to be a "professional engineer working in a senior role with significant autonomy and responsibility." It is the highest level of membership and demonstrates experience, commitment and contribution to engineering.
== Fellowship ==
Fellows are entitled to use the post-nominal letters FIMechE. As of 2016 examples of fellows include Colin P. Smith, Barry Thornton, William Pillar, Laurence Williams and Michael Alcock. See the Category:Fellows of the Institution of Mechanical Engineers for more examples.
== References ==

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Fiberglass molding is a process in which fiberglass reinforced resin plastics are formed into useful shapes.
The process usually involves first making a mold and then using the mold to make the fiberglass component.
== Mold making ==
The fiberglass mold process begins with an object known as the plug or buck. This is an exact representation of the object to be made. The plug can be made from a variety of materials, usually certain types of foam.
After the plug has been formed, it is sprayed with a mold release agent. The release agent will allow the mold to be separated from the plug once it is finished. The mold release agent is a special wax, and/or PVA (Polyvinyl alcohol). Polyvinyl alcohol, however, is said to have negative effects on the final mold's surface finish.
Once the plug has its release agent applied, gelcoat is applied with a roller, brush or specially designed spray gun. The gelcoat is pigmented resin, and gives the mold surface a harder, more durable finish.
Once the release agent and gelcoat are applied, layers of fiberglass and resin are laid-up onto the surface. The fiberglass used will typically be identical to that which will be used in the final product.
In the laying-up process, a layer of fiberglass mat is applied, and resin is applied over it. A special roller is then used to remove air bubbles. Air bubbles, if left in the curing resin, would significantly reduce the strength of the finished mold. The fiberglass spray lay-up process is also used to produce molds, and can provide good filling of corners and cavities where a glass mat or weave may prove to be too stiff.
Once the final layers of fiberglass are applied to the mold, the resin is allowed to set up and cure. Wedges are then driven between the plug and the mold in order to separate the two.
Advanced techniques such as resin transfer molding are also used.
== Making a component ==
The component-making process involves building up a component on the fiberglass mold. The mold is a negative image of the component to be made, so the fiberglass will be applied inside the mold, rather than around it.
As in the mold-making process, release agent is first applied to the mold. Colored gelcoat is then applied. Layers of fiberglass are then applied, using the same procedure as before. Once completed and cured, the component is separated from the mold using wedges, compressed air or both.
== See also ==
Fiber-reinforced plastic
Glass-reinforced plastic
Other types of mold processing
== References ==

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A filling carousel is a machine for filling large numbers of liquefied petroleum gas (LPG) cylinders from bulk storage. It consists of a frame with running wheels, rails, a central column for LPG and air, and a driving unit rotating the carousel frame around the central column. The speed of the carousel can be adapted to the various filling times and capacities. The dimension of the carousel is important to consider for the future filling capacity. The carousel frame chosen can be equipped with a number of filling scales, suited for the current demand and possible future demands. Filling carousels can be provided with equipment for automatic introduction and automatic filling scales with ejection of cylinders.
== Dimensions ==
Frame sizes and approximate filling times for 12 kg cylinders with two-man operation:
== Associated equipment ==
== How it works ==
LPG cylinders of a consistent size mass, and design are loaded onto the feed conveyor from incoming trucks. They may pass through an automatic washer and a check scale before being loaded onto the carousel at a filling point. A filling nozzle is automatically connected to the valve opening. Each filling point is equipped with an electronic scale to measure the mass of the cylinder while it is being filled, and to stop the flow when it is full. The rotation speed of the carousel will normally allow an empty cylinder to be filled and the filling nozzle automatically disconnected by the time it reaches the ejection point where it is pushed onto the discharge conveyor. The filled cylinder may pass through an automatic check scale, an automated leak detector, and valve cover heat shrink wrap applicator before it is carried to the outgoing truck for loading.
A spray-painting station may be provided to repair damaged paintwork.
== References ==

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Filling factor,
F
,
{\displaystyle ~F,~}
is a quantity measuring the efficiency of absorption of pump in the core of a double-clad fiber.
== Definition ==
The efficiency of absorption of pumping energy in the fiber is an important parameter of a double-clad fiber laser. In many cases this efficiency can be approximated with
1
−
exp
⁡
(
−
F
π
r
2
S
α
L
)
,
{\displaystyle 1-\exp \left(-F{\frac {\pi r^{2}}{S}}\alpha L\right),}
where
S
{\displaystyle ~S~}
is the cross-sectional area of the cladding
r
{\displaystyle ~r~}
is the radius of the core (which is taken to be circular)
α
{\displaystyle ~\alpha ~}
is the absorption coefficient of pump light in the core
L
{\displaystyle ~L~}
is the length of the double-clad fiber, and
F
{\displaystyle ~F~}
is a dimensionless adjusting parameter, which is sometimes called the "filling factor";
0
<
F
<
1
{\displaystyle ~0<F<1~}
.
The filling factor may depend on the initial distribution of the pump light, the shape of the cladding, and the position of the core within it.
== Application ==
The large (close to unity) filling factor is important in double-clad amplifiers; it allows them to reduce the requirements for the brightness of the pump and to reduce the length of the fiber laser. Such a reduction is especially important for the power scaling of various nonlinear processes, and contributions of stimulated scattering to the degradation of signal. Use of the filling factor for the estimate of the efficiency of absorption of the pump in fiber lasers allows quick estimates without performing complicated numerical simulations.
== See also ==
Double-clad fiber
Erbium Doped Fibre Amplifier (EDFA)
== Notes ==

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Fire Dynamics Simulator (FDS) is a computational fluid dynamics (CFD) model of fire-driven fluid flow. The computer program solves numerically a large eddy simulation form of the Navier–Stokes equations appropriate for low-speed, thermally-driven flow, with an emphasis on smoke and heat transport from fires, to describe the evolution of fire.
As of March 2026 the current stable release is FDS 6.10.1 (with companion visualisation tool Smokeview 6.10.1), published by NIST on 18 March 2025.
Version 6.10.0, issued on 12 March 2025, added three-dimensional heat conduction and a new heat-flux–scaling pyrolysis model aimed at improving predictions of burning rate for solid fuels. The underlying science and implementation of these features were detailed at FEMTC 2024.
A beta branch of FDS 7 is currently being evaluated at NIST’s Sandia FLAME facility.
FDS is free software developed by the National Institute of Standards and Technology (NIST) of the United States Department of Commerce, in cooperation with VTT Technical Research Centre of Finland. Smokeview is the companion visualization program that can be used to display the output of FDS.
The first version of FDS was publicly released in February 2000. To date, about half of the applications of the model have been for design of smoke-handling systems and sprinkler/detector activation studies. The other half consist of residential and industrial fire reconstructions. Throughout its development, FDS has been aimed at solving practical fire problems in fire protection engineering while at the same time providing a tool to study fundamental fire dynamics and combustion. Recent peer-reviewed studies employing FDS include reconstructions of a firefighter line-of-duty death in Pennsylvania, and analysis of fire development in lithium-ion battery energy-storage containers.
The Wildland-Urban Fire Dynamics Simulator (WFDS) is an extension developed by the US Forest Service that is integrated into FDS and allows it to be used for wildfire modeling. It models vegetative fuel either by explicitly defining the volume of the vegetation or, for surface fuels such as grass, by assuming uniform fuel at the air-ground boundary.
FDS is a Fortran program that reads input parameters from a text file, computes a numerical solution to the governing equations, and writes user-specified output data to files. Smokeview is a companion program that reads FDS output files and produces animations on the computer screen. Smokeview has a simple menu-driven interface, while FDS does not. However, there are various third-party programs that have been developed to generate the text file containing the input parameters needed by FDS.
== See also ==
Wildfire modeling
== References ==
== External links ==
FDS Official website
Wikibooks tutorial
FDS Tools
FDS Project Road Map
AutoCAD plugin to convert 3D geometry to FDS format
PyroSim, a graphical interface (GUI) for creation of FDS input files. (commercial)
Office Fire Emergency Evacuation Simulation on YouTube
Stack effect simulation on YouTube

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title: "First-order reliability method"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/First-order_reliability_method"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:28.596213+00:00"
instance: "kb-cron"
---
The first-order reliability method (FORM) is a semi-probabilistic reliability analysis method devised to evaluate the reliability of a system. The accuracy of the method can be improved by averaging over many samples, which is known as Line Sampling.
The method is also known as the Hasofer-Lind Reliability Index, developed by Professor Michael Hasofer and Professor Niels Lind in 1974. The index has been recognized as an important step towards the development of contemporary methods to effectively and accurately estimate structural safety.
The analysis method depends on a "Most Probable Point" on the limit state
== See also ==
EN 1990
Fast probability integration
Stress–strength analysis
== References ==

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title: "Flame polishing"
chunk: 1/1
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category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:29.773025+00:00"
instance: "kb-cron"
---
Flame polishing, also known as fire polishing, is a method of polishing a material, usually glass or thermoplastics, by exposing it to a flame or heat. When the surface of the material briefly melts, surface tension smooths the surface. Operator skill is critical with this method. When done properly, flame plastic polishing produces the clearest finish, especially when polishing acrylic. This method is most applicable to flat external surfaces. Flame polishing is frequently used in acrylic plastic fabrication because of its high speed compared to abrasive methods. In this application, an oxyhydrogen torch is typically used, one reason being that the flame chemistry is unlikely to contaminate the plastic.
Flame polishing is essential to creation of the glass pipettes used for the patch clamp technique of voltage clamping.
== Equipment ==
Various machines and torches/gas burners are used in the flame polishing process. Depending on the heating requirements for an intended application, different kinds of gases are used including but not limited to: natural gas, propane and oxygen, oxygen and hydrogen. A specially designed machine called the hydro flame is commonly used in flame polishing. The hydro flame is a gas-powered generator that uses distilled water and electricity to create oxygen and hydrogen for its flame. The size, shape, and chemistry of the flames used in fire polishing can vary widely based on the type and shape of the material being polished.
== See also ==
Fire hardening, also known as "fire polishing", a primitive process for hardening wood
== References ==

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title: "Float voltage"
chunk: 1/1
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category: "reference"
tags: "science, encyclopedia"
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instance: "kb-cron"
---
Float voltage is the voltage at which a battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery. The voltage could be held constant for the entire duration of the cell's operation (such as in an automotive battery) or could be held for a particular phase of charging by the charger. The appropriate float voltage varies significantly with the chemistry and construction of the battery, and ambient temperature.
With the appropriate voltage for the battery type and with proper temperature compensation, a float charger may be kept connected indefinitely without damaging the battery.
However, it should be understood that the concept of a float voltage does not apply equally to all battery chemistries. For instance, lithium ion cells have to be float charged with extra care because if they are float charged at just a little over optimum voltage, which is generally the full output voltage of the lithium cell, the chemical system within the cell will be damaged to some extent.
Some lithium ion variants are less tolerant than others, but generally overheating, which shortens cell life, is likely, and fire and explosion are possible other outcomes. It is important to make certain that the battery cell involved can be safely float charged, and that in the absence of protection from a battery management system, that the charger circuit goes into float charge status when full charge is achieved.
== Lead–acid batteries ==
Accepted average float voltages for lead–acid batteries at 25 °C can be found in the following table:
Temperature compensation
Compensation per cell of approximately −3.9 mV/°C (−2.17 mV/°F) of temperature rise is necessary.
Example 1
A 12 V (6-cell) battery at 30 °C (86 °F) (+5 °C change):
(−3.9 mV/°C) × (6 cells) × (5 °C change) = −117 mV
13.4 V (flooded battery float) + (−117 mV) = 13.28 V
Example 2
A 12 V (6-cell) battery at 20 °C (68 °F) (−5 °C change):
(−3.9 mV/°C) × (6 cells) × (−5 °C change) = +117 mV
(13.4 V flooded battery float) + (117 mV) = 13.52 V
Not compensating for temperature will shorten battery life by over- or undercharging.
== See also ==
Trickle charging – Charging a battery to keep it fully charged
== References ==

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title: "Flood bypass"
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tags: "science, encyclopedia"
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instance: "kb-cron"
---
A flood bypass is a region of land or a large man-made structure that is designed to convey excess flood waters from a river or stream in order to reduce the risk of flooding on the natural river or stream near a key point of interest, such as a city. Flood bypasses, sometimes called floodways, often have man-made diversion works, such as diversion weirs and spillways, at their head or point of origin. The main body of a flood bypass is often a natural flood plain. Many flood bypasses are designed to carry enough water such that combined flows down the original river or stream and flood bypass will not exceed the expected maximum flood flow of the river or stream.
Flood bypasses are typically used only during major floods and act in a similar nature to a detention basin. Since the area of a flood bypass is significantly larger than the cross-sectional area of the original river or stream channel from which water is diverted, the velocity of water in a flood bypass will be significantly lower than the velocity of the flood water in the original system. These low velocities often cause increased sediment deposition in the flood bypass, thus it is important to incorporate a maintenance program for the entire flood bypass system when it is not being actively used during a flood operation.
When not being used to convey water, flood bypasses are sometimes used for agricultural or environmental purposes. The land is often owned by a public authority and then rented to farmers or ranchers, who in turn plant crops or herd livestock that feed off the flood plain. Since the flood bypass is subjected to sedimentation during flood events, the land is often very productive and even a loss of crops due to flooding can sometimes be recovered due to the high yield of the land during the non-flood periods.
== Examples ==
Bonnet Carré Spillway
Eastside Bypass
Fargo-Moorhead Area Diversion Project
Yolo Bypass
== References ==

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title: "Flood control channel"
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tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:33.409938+00:00"
instance: "kb-cron"
---
Flood control channels are large and empty basins where surface water can flow through but is not retained (except during flooding), or dry channels that run below the street levels of some larger cities, so that if a flash flood occurs the excess water can drain out along these channels into a river or other bodies of water. Flood channels are sometimes built on the former courses of natural waterways as a way to reduce flooding.
Channelization of this sort was commonly done in the 1960s, but is now often being undone, with "rechannelization" through meandering, vegetated, and porous paths. This is because channelizing the flow in a concrete chute often made flooding worse.
Water levels during a flood tend to rise, then fall, exponentially. The peak flood level occurs as a very steep, short spike; a quick spurt of water. Anything that slows the surface runoff (marshes, meanders, vegetation, porous materials, turbulent flow, the river spreading over a floodplain) will slow some of the flow more than other parts, spreading the flow over time and blunting the spike. Even slightly blunting the spike significantly decreases the peak flood level. Generally, the higher the peak flood level, the more flood damage is done. Straight, clear, smooth concrete-walled channels speed up flow, and are therefore likely to make flooding downstream worse. Modern flood control seeks to "slow the flow", and deliberately flood some low-lying areas, ideally vegetated, to act as sponges, letting them drain again as the floodwaters go down.
== Levees ==
Flood control channels are not to be confused with watercourses which are simply confined between levees. These structures may be made entirely of concrete, with concrete sides and an exposed bottom, with riprap sides and an exposed bottom, or completely unlined. They often contain grade control sills or weirs to prevent erosion and maintain a level streambed.
== Distribution ==
By definition, flood control channels range from the size of a street gutter to a few hundred or even a few thousand feet wide in some rare cases. Flood control channels are found in most heavily developed areas in the world. One city with many of these channels is Los Angeles, as they became mandatory with the passage of the Flood Control Act of 1941 passed in the wake of the Los Angeles Flood of 1938.
== See also ==
Nullah
Drop structure
Urban runoff
Weir
Levee
== References ==
== External links ==
LA River Flood Control Channel
Guadalupe River Flood Control Channel

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title: "Floodway (road)"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Floodway_(road)"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:34.620008+00:00"
instance: "kb-cron"
---
A floodway is a flood plain crossing for a road, built at or close to the natural ground level. It is similar to a causeway, but crosses a shallow depression that is subject to flooding, rather than a waterway or tidal water.
They are designed to be submerged under water, but withstand such conditions. Typically floodways are used when the flood frequency or time span is minimal, traffic volumes are low, and the cost of a bridge is uneconomic – in most cases, in rural areas.
== See also ==
Flood control channel
Glossary of road transport terms
Low water crossing
== Notes ==
Department of Transport and Main Roads (March 2010). "Chapter 10 Floodway Design" (PDF). Road Drainage Manual. Queensland Government.
Lokuge, Weena; Setunge, Sujeeva; Karunasena, Warna (2014). Investigating the performance of floodway in an extreme flood event (PDF). 1st International Conference on Infrastructure Failures and Consequences (ICFC 2014) 16–20 July 2014. Melbourne, Australia.
Greene, I.; Lokuge, W.; Karunasena f, W. (2020). Floodway Design Process Revisted (PDF). 25th Australasian Conference on Mechanics of Structures and Materials (ACMSM25), 4–7 December 2018. Brisbane, Australia – via University of Southern Queensland.
== External links ==

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title: "Flow control (fluid)"
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instance: "kb-cron"
---
Flow control is a field of fluid dynamics. It involves a small configuration change to serve an ideally large engineering benefit, like drag reduction, lift increase, mixing enhancement or noise reduction. This change may be accomplished by passive or active devices.
== Passive vs active ==
Passive devices by definition require no energy. Passive techniques include turbulators or roughness elements geometric shaping, the use of vortex generators, and the placement of longitudinal grooves or riblets on airfoil surfaces.
Active control requires actuators that require energy and may operate in a time-dependent manner. Active flow control includes steady or unsteady suction or blowing, the use of synthetic jets, valves and plasma actuators. Actuation may be pre-determined (open-loop control) or be dependent on monitoring sensors (closed-loop control).
== Aircraft wings ==
Airplane wing performance has a substantial effect on not only runway length, approach speed, climb rate, cargo capacity, and operation range but also noise and emissions. Wing performance can be degraded by flow separation, which depends on the aerodynamic characteristics of the airfoil. Aerodynamic and non-aerodynamic constraints often conflict. Flow control is required to overcome such difficulties. Techniques developed to manipulate the boundary layer, either to increase lift or decrease drag, and separation delay come under the general heading of flow control.
Aurora Flight Sciences is a DARPA CRANE (Control of Revolutionary Aircraft with Novel Effectors) grantee. It initially involved testing a small-scale plane that uses compressed air bursts instead of external moving parts such as flaps. The program seeks to eliminate the weight, drag, and mechanical complexity involved in moving control surfaces. The air bursts modify the air pressure and flow, and change the boundaries between streams of air moving at different speeds. The company built a 25% scale prototype with 11 conventional control surfaces, as well as 14 banks fed by eight air channels. In 2023, the aircraft received its official designation as X-65. In January 2024, DARPA and Aurora started CRANE Phase 3, building the first full-scale X-65 aircraft using active flow control actuators for primary flight control. The 7,000-pound X-65 will be rolled out in early 2025 with the first flight planned for summer of 2025.
== References ==

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title: "Flow splitter"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Flow_splitter"
category: "reference"
tags: "science, encyclopedia"
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instance: "kb-cron"
---
A flow splitter, additionally referred to as a flow divider, is a device in hydraulic engineering designed to break up the flow of water or nappe over a dam wall or weir. This flow can be broken up into differing ratios, which varies depending on the type of flow splitter. Flow splitters are used to reduce the likelihood of nappe vibration that might cause the failure of a dam wall by aerating the water flow. They are also used to restrict large flows of stormwater, in situations where a stormwater management device is designed only to treat small storms.
Another use for a flow splitter is to again break up the nappe so as to allow fish, such as salmon to swim upstream and over small weirs.
Split flow weirs are also used in drinking water and wastewater treatment plants (sewage treatment or industrial wastewater treatment) to proportion flows to different outlets in a junction box.
== Types of Flow Splitters ==
Flow splitters are known in various forms including, but not limited to:
Rotary / Gear type
Spool type
Motor type
Spool type dividers allow for the input flow to be split into countless ratios through two outputs. This divider allows upkeep on its continuous flow through the freedom of movement within the housing, even against changes in loads and pressures. The flow of liquid through spool type splitters start at the center and flow out towards the two outputs. An obstruction in either section of the two in this splitter results in the entirety of the component to be impeded.
Motor type flow splitters change the ratios in flow based on the number of hydraulic motors that are connected to the main feed. The use of two hydraulic motors can form a 50/50 split in flow, with additional motors allowing for versatility in the ratio. Displacement is a factor in the adjustment of these ratios. With two hydraulic motors, one having a displacement that equals three times the second, results in a 75%/25% split in the flow.
The gear type splitter creates two or more flow paths through its use of mating gears located within the housing. With the input flow traveling through housing, the liquid flows through the component and splits as the interlinked gears move with the liquid acting against them. All of the gears move at the same speed since they are connected. This allows for an even flow of the liquid. The output flow behaves corresponding to the input flow. If the input flow is adjusted, this will affect the output flow. Similarly to the spool type splitter, having one output obstructed means the other outputs are also effected.
Performance can be hindered in the same way as other hydraulic components, one being air that is trapped.
Flow splitters are often manufactured with the consideration of varying uses in mind. This change in performance is created through the making of splitters varying in flow, accuracy and pressure.
== See also ==
Flow control structure
== References ==

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title: "Flow stress"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Flow_stress"
category: "reference"
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instance: "kb-cron"
---
In materials science, the flow stress, typically denoted as
Y
f
{\displaystyle Y_{\text{f}}}
(or
σ
f
{\displaystyle \sigma _{\text{f}}}
), is defined as the instantaneous value of stress required to continue plastically deforming a material - to keep it flowing. It is most commonly, though not exclusively, used in reference to metals. On a stress-strain curve, the flow stress can be found anywhere within the plastic regime; more explicitly, a flow stress can be found for any value of strain between and including yield point (
σ
y
{\displaystyle \sigma _{\text{y}}}
) and excluding fracture (
σ
F
{\displaystyle \sigma _{\text{F}}}
):
σ
y
≤
Y
f
<
σ
F
{\displaystyle \sigma _{\text{y}}\leq Y_{\text{f}}<\sigma _{\text{F}}}
.
The flow stress changes as deformation proceeds and usually increases as strain accumulates due to work hardening, although the flow stress could decrease due to any recovery process. In continuum mechanics, the flow stress for a given material will vary with changes in temperature,
T
{\displaystyle T}
, strain,
ε
{\displaystyle \varepsilon }
, and strain-rate,
ε
˙
{\displaystyle {\dot {\varepsilon }}}
; therefore it can be written as some function of those properties:
Y
f
=
f
(
ε
,
ε
˙
,
T
)
{\displaystyle Y_{\text{f}}=f(\varepsilon ,{\dot {\varepsilon }},T)}
The exact equation to represent flow stress depends on the particular material and plasticity model being used. Hollomon's equation is commonly used to represent the behavior seen in a stress-strain plot during work hardening:
Y
f
=
K
ε
p
n
{\displaystyle Y_{\text{f}}=K\varepsilon _{\text{p}}^{\text{n}}}
Where
Y
f
{\displaystyle Y_{\text{f}}}
is flow stress,
K
{\displaystyle K}
is a strength coefficient,
ε
p
{\displaystyle \varepsilon _{\text{p}}}
is the plastic strain, and
n
{\displaystyle n}
is the strain hardening exponent. Note that this is an empirical relation and does not model the relation at other temperatures or strain-rates (though the behavior may be similar).
Generally, raising the temperature of an alloy above 0.5 Tm results in the plastic deformation mechanisms being controlled by strain-rate sensitivity, whereas at room temperature metals are generally strain-dependent. Other models may also include the effects of strain gradients. Independent of test conditions, the flow stress is also affected by: chemical composition, purity, crystal structure, phase constitution, microstructure, grain size, and prior strain.
The flow stress is an important parameter in the fatigue failure of ductile materials. Fatigue failure is caused by crack propagation in materials under a varying load, typically a cyclically varying load. A higher flow stress generally means the material is more resistant to fatigue initiation and propagation, especially in low-cycle fatigue conditions where plastic deformation is prominent.
== References ==

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title: "Flushing hydrant"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Flushing_hydrant"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:39.330762+00:00"
instance: "kb-cron"
---
A flushing hydrant is a hydrant that is used for flushing a water line of silt, rust, debris, or stagnant water. Many water utilities use standard fire hydrants for flushing their lines. Specialized flushing hydrants are often smaller and less expensive than a fire hydrant to reduce cost where fire fighting use is not needed or practical. Many flushing hydrants are "unidirectional": they only have one outlet, in contrast to fire hydrants, which normally have two or three.
Flushing hydrants are commonly installed at the end of dead-end water lines.
== See also ==
Fire hydrant
== References ==

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title: "Forming processes"
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category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:40.525394+00:00"
instance: "kb-cron"
---
Forming processes are particular manufacturing processes which make use of suitable stresses (like compression, tension, shear or combined stresses) which cause plastic deformation of the materials to produce required shapes.
Since 2001, demand has increased for microforming components for miniaturized products.
== Types ==
Some examples of forming processes are:
Forging
Extrusion
Rolling
Sheet metal working
Rotary swaging
Thread rolling
Explosive forming
Electromagnetic forming
Plastic extrusion
Die forming
Food extrusion
== References ==
== See also ==
Metalworking § Forming processes
Forming (metalworking) § Forming processes
Pedogenesis - soil forming processes

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title: "Foundation integrity testing"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Foundation_integrity_testing"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:41.682288+00:00"
instance: "kb-cron"
---
Foundation integrity testing is the non-destructive testing of piled foundations. It was first used in the late 1960s, and has been developed over time by many companies. Three organizations supply a majority of the test equipment in use: CEBTP (Centre Expérimental de Recherches et d'Etudes du Bâtiment et des Travaux Publics) in Europe; Integrity Testing in Asia and Australia: and by GRL in the USA.
== References ==

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title: "Frequency domain decomposition"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Frequency_domain_decomposition"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:42.861016+00:00"
instance: "kb-cron"
---
The frequency domain decomposition (FDD) is an output-only system identification technique popular in civil engineering, in particular in structural health monitoring. As an output-only algorithm, it is useful when the input data is unknown. FDD is a modal analysis technique which generates a system realization using the frequency response given (multi-)output data.
== Algorithm ==
Estimate the power spectral density matrix
G
^
y
y
(
j
ω
)
{\displaystyle {\hat {G}}_{yy}(j\omega )}
at discrete frequencies
ω
=
ω
i
{\displaystyle \omega =\omega _{i}}
.
Do a singular value decomposition of the power spectral density, i.e.
G
^
y
y
(
j
ω
i
)
=
U
i
S
i
U
i
H
{\displaystyle {\hat {G}}_{yy}(j\omega _{i})=U_{i}S_{i}U_{i}^{H}}
where
U
i
=
[
u
i
1
,
u
i
2
,
.
.
.
,
u
i
m
]
{\displaystyle U_{i}=[u_{i1},u_{i2},...,u_{im}]}
is a unitary matrix holding the singular vectors
u
i
j
{\displaystyle u_{ij}}
,
S
i
{\displaystyle S_{i}}
is the diagonal matrix holding the singular values
s
i
j
{\displaystyle s_{ij}}
.
For an
n
{\displaystyle n}
degree of freedom system, then pick the
n
{\displaystyle n}
dominating peaks in the power spectral density using whichever technique you wish (or manually). These peaks correspond to the mode shapes.
Using the mode shapes, an input-output system realization can be written.
== See also ==
Eigensystem realization algorithm - an input/output identification technique
== References ==

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title: "Friction motor"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Friction_motor"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:44.067970+00:00"
instance: "kb-cron"
---
A friction motor is a simple mechanism to propel toy cars, trucks, trains, action figures and similar toys. The motor consists of a large flywheel which is connected to the drive wheels of the toy via a gear train with very low gear ratio, so that the flywheel revolves much faster than the wheels. The flywheel's axis is perpendicular to the direction in which the toy faces and in which it moves. When the toy is pushed forward, the drive wheels engage the flywheel. If higher energies are desired, pushing the vehicle forward repeatedly spins this flywheel up to greater speed. When let go, the flywheel drives the vehicle forward. Energy which is input by pushing the car is stored by the flywheel as rotational kinetic energy and can propel the toy after it is released. It is friction between the tyres and the surface on which the vehicle is operating which enables the energy input process, thus giving the name "friction motor" to the device.
As the flywheel, unlike the spring of a pullback motor, is continuously rotating, the motor may be "pumped up" by pushing the car repeatedly forward. In some cases, the cars work both in forward and reverse; in other cases, a one-way clutch can disengage a component in the gear assembly to prevent input of rotational effort in the reverse sense. Some used a zip cord pulled from the vehicle body to accelerate the flywheel directly. Another system was the Turbo Tower of Power (TTP) in which air expelled from a hand-operated pump pushed turbine blades on the flywheel's rim.
These toys were especially popular in the 1960s to 1980s though they continue to be available today.
== Weblinks ==
== References ==

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title: "Friction surfacing"
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category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:48:45.225547+00:00"
instance: "kb-cron"
---
Friction surfacing is a process derived from friction welding where a coating material is applied to a substrate. A rod composed of the coating material (called a mechtrode) is rotated under pressure, generating a plasticised layer in the rod at the interface with the substrate. By moving a substrate across the face of the rotating rod a plasticised layer is deposited, typically between 0.2–2.5 millimetres (0.0079–0.0984 in) thick with steels on steels, depending on mechtrode diameter and coating material. The process can be used with various metals, including aluminium on to aluminium.
== See also ==
Friction welding
== References ==

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A frontal solver is an approach to solving sparse linear systems which is used extensively in finite element analysis. Algorithms of this kind are variants of Gauss elimination that automatically avoids a large number of operations involving zero terms due to the fact that the matrix is only sparse. The development of frontal solvers is usually considered as dating back to work by Bruce Irons.
A frontal solver builds a LU or Cholesky decomposition of a sparse matrix.
Frontal solvers start with one or a few diagonal entries of the matrix, then consider all of those diagonal entries that are coupled to the first set via off-diagonal entries, and so on. In the finite element context, these consecutive sets form "fronts" that march through the domain (and consequently through the matrix, if one were to permute rows and columns of the matrix in such a way that the diagonal entries are ordered by the wave they are part of). Processing the front involves dense matrix operations, which use the CPU efficiently.
Given that the elements of the matrix are only needed as the front marches through the matrix, it is possible (but not necessary) to provide matrix elements only as needed. For example, for matrices arising from the finite element method, one can structure the "assembly" of element matrices by assembling the matrix and eliminating equations only on a subset of elements at a time. This subset is called the front and it is essentially the transition region between the part of the system already finished and the part not touched yet. In this context, the whole sparse matrix is never created explicitly, though the decomposition of the matrix is stored. This approach was mainly used historically, when computers had little memory; in such implementations, only the front is in memory, while the factors in the decomposition are written into files. The element matrices are read from files or created as needed and discarded. More modern implementations, running on computers with more memory, no longer use this approach and instead store both the original matrix and its decomposition entirely in memory.
A variation of frontal solvers is the multifrontal method that originates in work of Duff and Reid. It is an improvement of the frontal solver that uses several independent fronts at the same time. The fronts can be worked on by different processors, which enables parallel computing.
See for a monograph exposition.
== See also ==
MUMPS
UMFPACK
Skyline matrix
Banded matrix
== References ==

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Fukushima Hydrogen Energy Research Field (FH2R) is the world's largest hydrogen production facility using renewable energy. It is located in Fukushima Prefecture in Japan. The construction was started in 2018 and it was inaugurated by Shinzo Abe in 2020. The facility uses 10 MW of solar electricity which is installed near the production facility. The facility can produce 1,200 Nm3 of hydrogen per hour. It was jointly established by the New Energy and Industrial Technology Development Organization, Toshiba Energy Systems & Solutions Corporation, Tohoku Electric Power and Iwatani Corporation.
== References ==
== External links ==
Description of FH2R used technology

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Fun with Radio is a book by Gilbert Davey first published in 1957 by Edmund Ward Ltd (London).
Written when radio receivers were still very expensive, and portable radios still a rarity (transistors were just being introduced), the book aimed to introduce children, mainly boys, to radio construction and possibly a career in radio or electronics. Radio construction was, in the early years of broadcasting, a very popular hobby among boys. By the time he published 'Fun with Radio', Davey already had a following among readers of the Boy's Own Paper, where he was said to be the most popular contributor on practical subjects among its readers, and in that same year he presented a series on BBC Television's Studio 'E' which reportedly brought him 26,000 letters within a few days of the first broadcast.
Six editions of the book were published, the final one in 1978. Davey also wrote Fun with Short Wave Radio, Fun with Transistors, Fun with Hi-Fi, and Fun with Silicon Chips in Modern Radio (1981).
== References ==

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In engineering, a function is interpreted as a specific process, action or task that a system is able to perform.
== In engineering design ==
In the lifecycle of engineering projects, there are usually distinguished subsequently: Requirements and Functional specification documents. The Requirements usually specifies the most important attributes of the requested system. In the Design specification documents, physical or software processes and systems are frequently the requested functions
== In products ==
For advertising and marketing of technical products, the number of functions they can perform is often counted and used for promotion. For example a calculator capable of the basic mathematical operations of addition, subtraction, multiplication, and division, would be called a "four-function" model; when other operations are added, for example for scientific, financial, or statistical calculations, advertisers speak of "57 scientific functions", etc. A wristwatch with stopwatch and timer facilities would similarly claim a specified number of functions. To maximise the claim, trivial operations which do not significantly enhance the functionality of a product may be counted.
== References ==
== See also ==
Process
System
Utility

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In engineering design, a function–means tree (a.k.a. function/means tree or F/M tree) is a method for functional decomposition and concept generation. At the top level, main functions are identified. Under each function, a means (or solution element) is attached. Alternative solution elements can also be attached. Each means is in turn decomposed into functions with means attached to each of them. A well-elaborated function means tree span, a design space where all concepts under consideration are represented.
In addition to product level requirements, there might be requirements on sub functions that may be a consequence of means at a higher level. The function means tree is a tool that can aid in the creative part of the design process. It can also be a tool for mapping requirements to parts in a design.
== References ==
== Further reading ==
Barry O'Sullivan (2002). Constraint-Aided Conceptual Design. John Wiley and Sons. p. 11. ISBN 1-86058-335-0.
Claus Thorp Hansen and Mogens Myrup Andreasen (2002). "Two approaches to synthesis based on the domain theory". In Amaresh Chakrabarti (ed.). Engineering Design Synthesis: Understanding, Approaches, and Tools. Springer. pp. 99. ISBN 1-85233-492-4.
Mogens Myrup Andreasen (1980). Machine Design Methods Based on a Systematic Approach - Contribution to a Design Theory. Dissertation (in Danish), Department of Machine Design, Lund Institute of Technology, Sweden.

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A Gasoline Particulate Filter (GPF) is an emissions control device designed to reduce fine particulate emissions from gasoline direct injection (GDI) engines. It is derived from the diesel particulate filter (DPF), which became common on diesel engine vehicles before stricter emissions standards such as Euro VI and China 6a required similar systems for gasoline engines used in light-duty automobiles.
Unlike DPFs that capture relatively large soot particles, gasoline particulate filters are optimized to capture fine particulates measuring 2.5 microns (PM2.5) and smaller. These particulates are particularly prevalent in gasoline direct injection engines due to incomplete combustion of fuel droplets during the combustion process.
== Operation ==
A GPF typically consists of a porous honeycomb structure made from ceramic cordierite, a material commonly used in catalytic converters and diesel particulate filters due to its low thermal expansion and high resistance to thermal shock. The GPF is installed in the exhaust system downstream of the catalytic converters.
When exhaust gases flow through the filter, particulate matter becomes trapped within the cell walls. Under suitable conditions—typically when exhaust gas temperatures exceed 600 °C (1,100 °F)—these particulates are oxidized into carbon dioxide in the presence of oxygen, particularly during engine overrun.
If oxidation does not occur for extended periods, the trapped particulates can accumulate and gradually increase back pressure in the exhaust, potentially affecting engine performance. This issue is less common in gasoline engines than in diesel engines because gasoline engines generally operate with higher exhaust temperatures.
When necessary, a process known as regeneration is triggered by the engine control unit (ECU). The ECU temporarily increases exhaust temperature, often by adjusting the air–fuel ratio to run leaner. The elevated temperature enables the oxidation of accumulated soot, clearing the filter and restoring normal exhaust flow.
== Applications ==
Gasoline particulate filters are most commonly found in light-duty passenger vehicles equipped with gasoline direct injection engines that are subject to modern emissions standards such as Bharat Stage 6, Euro VI, China 6a, or EPA Tier 4. These regulations set strict limits on particulate emissions and mandate filtration technologies in many markets.
In Europe, all PSA Group models have been fitted with GPFs since late 2017. Manufacturers such as Volkswagen Group—whose brands include Volkswagen, Audi, SEAT, and Škoda—and BMW have also implemented GPFs across their vehicle lineups since 2018. Other brands including Mercedes-Benz, Volvo, and Opel have similarly adopted this technology.
High-performance vehicles are also subject to these regulations. Cars such as the Porsche 911 range (including the GT3 variant), the Audi R8, and various models from Ferrari beginning with the F8 Tributo employ gasoline particulate filters to meet European emission norms. An exception is the Lamborghini Huracán Evo, which shares a similar engine design to the Audi R8 but does not use a GPF, as its combination of fuel injection systems—both port and direct—reduces particulate formation and prevents excessive soot accumulation.
In the United States, EPA Tier 4 standards, which restrict particulate emissions from gasoline vehicles, are scheduled to come into effect starting in 2027. As of March 2026, Ford has begun implementing GPFs on models such as the Maverick and the F-150 powered by EcoBoost engines.
== References ==

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Genivar Inc. was a Canadian engineering consulting firm. As of January 1, 2014, it became WSP Global. Its head office remains located at 1600 René Lévesque Boulevard West in Montreal, Quebec.
On August 29, 2011, Genivar Inc. and Montreal-based architectural firm Arcop announced a strategic alliance.
On June 7, 2012, Genivar Inc. announced that it made a friendly takeover cash offer of C$442 million (£278 million) for WSP Group PLC. The offer is backed by WSP's board of directors as well as investors holding 37% of the company's shares. The deal closed on August 1, 2012.
In 2013, the company announced it will be changing its name to WSP Global, reflecting a $442-million purchase of the British-based WSP Group PLC. The rebrand followed a reorganisation to a holding structure that enabled the company to separate its regional operations into distinct subsidiaries.
== References ==
Van Praet, Nicolas (17 April 2013). "Genivar rebranding as WSP Global amid Quebec corruption scandal". Financial Post. Retrieved 1 November 2019.
== External links ==
GENIVAR

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title: "Geometrically and materially nonlinear analysis with imperfections included"
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Geometrically and materially nonlinear analysis with imperfections included (GMNIA), is a structural analysis method designed to verify the strength capacity of a structure, which accounts for both plasticity and buckling failure modes.
GMNIA is currently considered the most sophisticated and perspectively the most accurate method of a numerical buckling strength verification.
== References ==

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date_saved: "2026-05-05T11:48:55.835183+00:00"
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The Glass Packaging Institute (GPI) is the North American trade association for the glass container industry, headquartered in Arlington, Virginia. Through GPI, glass container manufacturers advocate job preservation and industry standards, and promote sound energy, environmental, and recycling policies.
== Organization ==
The GPI membership consists of 5 glass container manufacturing member companies, and 27 supplier member companies, who provide raw materials, recycled glass, equipment, decorating, and other services to the glass companies. The country's 41 glass container plants in 20 states comprise a $5.5 billion industry. U.S. glass container manufacturers operate 102 glass furnaces, collectively producing 30 billion glass food, beverage, cosmetic, spirits, wine, and beer containers annually. The U.S. glass container industry directly employs approximately 16,500 nationwide, and its supplier and customer companies support hundreds of thousands of additional jobs.
GPI's board of trustees is the core decision-making body in the organization. It is made up of representatives from each of the glass container manufacturing member companies, as well as two representatives from the associate member companies (supplier member companies). The Trustees meet quarterly for budget, agenda and future planning purposes.
GPI hosts two meetings each year: a spring membership meeting in Washington, D.C., and an annual meeting in the fall.
Scott DeFife serves as the trade association's president.
The board is supported with a series of committees, including Marketing and Communications, Government Affairs & Regulatory Affairs, Environment, Labor & HR, Design and Specifications Committee and Management Committee.
== Container finish standards ==
GPI publishes a voluntary set of standards for glass container finishes and their closures to improve compatibility and interchangeability between manufacturers. This includes vials, wine bottles, canning jars, beer bottles, and jugs. They are specified by the nominal outside diameter in millimeters followed by the glass finish number. For example, an 8-425 finish is approximately 8 mm neck outside diameter with a 425 finish corresponding to a threaded neck typically found on small vials.
== References ==
== External links ==
Institute website

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Glava AS is a Norwegian industrial company with headquarters in Askim. The name is a portmanteau of the Norwegian word glassvatt, meaning glass wool. Glass wool used as insulation material is the company's main product. Production takes place at the company's production facilities in Askim and Stjørdal. Glava employs around 500 people, and in 2007 had a revenue just short of NOK 1,500 million.
The company's history goes back to 1935, when industrialist Jens Bull was offered licensed production in Norway of glass wool, originally a German invention. The company was originally called "Glassvatt". During the post-war reconstruction of Norway, Glava grew dramatically, as the need for insulation of buildings became clear. The product is today made on a license from the French company Saint-Gobain. It is produced from borosilicate glass, which is heated to around 1,400 °C before being stretched into fibres.
In 1959, the company was responsible for the so-called "ice block expedition", later called "the world's greatest publicity stunt". The expedition consisted in bringing a three-ton block of ice from Mo i Rana by the Arctic Circle, to Libreville by the Equator, without using any form of refrigeration.
== References ==

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title: "Global Powder Metallurgy Property Database"
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The Global Powder Metallurgy Database (GPMD) is an online searchable database which launched in 2004. It was developed as the result of a joint project between leading regional powder metallurgy (PM) trade associations, the EPMA in Europe and its sister organisations in Japan (JPMA) and North America (MPIF). It was created to address the lack of readily accessible design data, which had been a significant impediment to the wider application of PM products. The Asian PM Association (APMA) joined as a database partner in 2020.
Primarily aimed at designers and engineers in the industries using PM products, it is designed to provide verified physical, mechanical and fatigue data for a range of commercially available PM materials. This culminated in the initial launch of the database at the PM World Congress in Vienna in October 2004. The content of the database, at this launch, was restricted to data on low alloy ferrous and stainless steel PM structural part grades and bronze and iron-based PM bearing grades.
However, enhancement and extension of content and searching capability has been an ongoing process ever since. In January 2007, the content was expanded with the addition of data on non-ferrous PM structural part grades, followed, in March 2007, by the introduction of a new section covering data on Metal Injection Moulding (MIM) materials.
The latest extension to capability involves making full SN Fatigue Curve "pages" (comprising SN curves and details of individual test points) accessible to searchers. The initial content comprises over 130 SN Curve pages, covering a range of Fe-Cu-C grades and based on published information that has been analysed and collated by the group led by Professor Paul Beiss at the Technical University of Aachen. The collated SN curves cover a range of material processing conditions and density levels and a range of fatigue testing conditions (fatigue loading mode, mean stress level and notch factor).
In assembling the GPMD content, a broad range of mechanical, fatigue and physical property data has been collected from the associations’ memberships and rigorously evaluated by regional accreditation committees. However, the database's primary targets are designers and material specifiers in end-user industries who may have no prior knowledge of PM. Therefore, the bulk of the search structure has been designed to take such a searcher to the point where they can decide that they ought to contact a PM parts manufacturer to discuss a potential application in more detail.
== References ==
== External links ==
Global Powder Metallurgy Property Database

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Good engineering practice (GEP) is engineering and technical activities that ensure that a company manufactures products of the required quality as expected (e.g., by the relevant regulatory authorities). Good engineering practices are to ensure that the development and/or manufacturing effort consistently generates deliverables that support the requirements for qualification or validation. Good engineering practices are applied to all industries that require engineering.
== See also ==
GxP
Good manufacturing practice (GMP)
Best practice
American National Standards Institute (ANSI)
Institute of Electrical and Electronics Engineers (IEEE)
European Medicines Agency (EMEA)
Food and Drug Administration (FDA)
Ministry of Health, Labour and Welfare (Japan)
Pharmaceutical Inspection Convention and Pharmaceutical Inspection Co-operation Scheme (PIC/S)
== References ==
== Sources ==
Risk-Based Qualification for the 21st Century
ISPE GAMP COP

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A gravity-based structure (GBS) is a support structure held in place by gravity, most notably offshore oil platforms. These structures are often constructed in fjords due to their protected area and sufficient depth.
== Offshore oil platforms ==
Prior to deployment, a study of the seabed must be done to ensure it can withstand the vertical load from the structure. It is then constructed with steel reinforced concrete into tanks or cells, some of which are used to control the buoyancy. When construction is complete, the structure is towed to its intended location.
Notable GBSs include the 1997 Hibernia Gravity Base Structure off Newfoundland. Around 2020 GBSes became the fashion for Novatek's exploitation of the petroleum resources in the Gulf of Ob.
== Wind turbines ==
Early deployments of offshore wind power turbines used these structures. As of 2010, 14 of the world's offshore wind farms had some of their turbines supported by gravity-based structures. The deepest registered offshore wind farm with gravity-based structures is the Blyth Offshore Wind Farm, UK, with a depth of approx. 40 m.
== See also ==
Offshore concrete structure
List of tallest oil platforms
Troll A platform
Gullfaks C
Hibernia (oil field)
== References ==

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The Great Kite (Italian: il Grande Nibbio) was a wooden machine designed by Leonardo da Vinci. Leonardo realized it between the end of the 15th Century and the beginning of the 16th Century. Drawings of parts and components of this machine can be found in the Codex on the flight of birds, which however lacks the overall description of the machine itself. Some drawings within the same codex suggest that it was created in similarity with flapping flight. However, this was hardly possible to perform given the available technologies, thus Leonardo developed a machine for mainly a gliding flight. The machine is named after the animal from which Leonardo took inspiration to realize the flying machine, the Kite.
== In-Media Appearances ==
The Great Kite makes an appearance in Mr. Peabody & Sherman.
The Great Kite appears as a Lego set released in 2025.
== See also ==
List of works by Leonardo da Vinci
Science and inventions of Leonardo da Vinci
== Note ==

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Ground conductivity refers to the electrical conductivity of the subsurface of the earth. In the International System of Units (SI) it is measured in millisiemens per meter (mS/m).
== Radio propagation ==
Ground conductivity is an extremely important factor in determining the field strength and propagation of surface wave (ground wave) radio transmissions. Low frequency (30–300 kHz) and medium frequency (300–3000 kHz) radio transmissions are particularly reliant on good ground conductivity as their primary propagation is by surface wave. It also affects the real world radiation pattern of high frequency (3-30 MHz) antennas, as the so-called "takeoff angle" is not an inherent property of the antenna but a result of a ground reflection. For this reason ITU publishes an extensive world atlas of ground conductivities.
== Other uses ==
Ground conductivity is sometimes used in determining the efficiency of a septic tank, using electromagnetic induction, so that contaminants do not reach the surface or nearby water supplies.
== References ==
== External links ==
Ground conductivity maps in the United States (provided by the Federal Communications Commission and includes large scale map)
Measurement of the ground conductivity and relative permittivity with high frequency using an open wire line (OWL) (Practical example with network analyzer and mathematics for the conversion)

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A guardian valve is a valve used in marine steam turbine propulsion plants to prevent steam from leaking into the astern turbine while the vessel is operating in the ahead mode. It is normally installed between the astern throttle valve and the astern elements of the low pressure (LP) turbine. Typically only the LP turbine of a steam ship's propulsion plant has reversing blade elements. Steam leaking in such a manner would result in a loss of efficiency and possibly overheat and damage the turbine blades.
The guardian valve must be opened prior to any maneuvering situation, in order to permit the astern turbine to be used to bring the vessel to a rapid stop or to back down.
Any similar arrangement of a stop valve used to protect leaking past a throttling valve could also be referred to as a guardian valve.
== References ==

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The guided-rotor compressor (GRC) is a positive-displacement rotary gas compressor. The compression volume is defined by the trochoidally rotating rotor mounted on an eccentric drive shaft with a typical 80 to 85% adiabatic efficiency.
== History ==
The development of the GRC started in 1990 to minimize the use of compressor valve plates and springs by using simple inlet/discharge ports.
== Uses ==
The guided-rotor compressor is under research as a hydrogen compressor for hydrogen stations and hydrogen pipeline transport.
== See also ==
Liquid-ring pump – Type of rotating positive-displacement pump
Rotary-screw compressor – Gas compressor using a rotary positive-displacement mechanism
Rotary vane pump – Type of positive-displacement pump
== References ==

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---
A guideline tensioner is a hydropneumatic device used on an offshore drilling rig that keeps a positive pulling force on the guidelines from the platform to a template on the seabed.
The guidelines act as a guidance for equipment and tools that must be lowered to the template. If there was no tensioner and the platform moved, the guidelines would become slack and could be broken. For this reason a number of guideline tensioners are mounted between the platform and riser. Each of these guideline tensioners consists of a hydraulic cylinder with sheaves at both sides. The cylinder is connected to one or more high pressure gas bottles via a medium separator. A wire rope is rigged in the cylinder; one end is connected to the fixed part of the tensioner, the other end to the template.
== See also ==
Drill string compensator
Riser tensioner
Hydraulic jigger
== References ==

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HARMST is an acronym for high aspect ratio microstructure technology, which describes fabrication technologies,
used to create high-aspect-ratio microstructures with heights between tens of micrometers up to a centimeter, and aspect ratios greater than 10:1. Examples include the LIGA fabrication process, advanced silicon etch, and deep reactive ion etching.
== See also ==
LIGA
Micromechanical systems — high aspect ratio (HAR) micromachining
== References ==

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Harmonic and Individual Lines and Noise (HILN) is a parametric codec for audio. The basic premise of the encoder is that most audio, and particularly speech, can be synthesized from only sinusoids and noise. The encoder describes individual sinusoids with amplitude and frequency, harmonic tones by fundamental frequency, amplitude and the spectral envelope of the partials, and the noise by amplitude and spectral envelope. This type of encoder is capable of encoding audio to between 6 and 16 kilobits per second for a typical audio bandwidth of 8 kHz. The framelength of this encoder is 32 ms.
A typical codec extracts sinusoid information from the samples by applying a short-time Fourier transform to the samples and using that to find the important harmonic content of a single frame. By matching sinusoids across frames, the encoder is capable of grouping them into harmonic lines and individual sinusoids. The matching can take amplitude, frequency and phase into account when trying to match sinusoids across frames. Differences between amplitude and frequency within a track can be coded with fewer bits than each individual single sinusoid would require, thus the longer a track the encoder can find, the better it will be able to reduce the final bitrate.
The decoder uses an add-and-overlap strategy: each frame in the bitstream contains parameters for 32 ms, however, the next frame starts halfway through the current frame. By filtering the synthesized segments with a Hanning filter, adding two overlapping frames together will produce a smooth transition between the two. This also applies to the encoder because the short Fourier transform gives better results when the data is pre-processed with a Hanning filter.
Synthesizing only the sinusoids sounds artificial and metallic. To mask this, the encoder subtracts the synthesized sinusoids from the original audio signal. The residual is then matched to a linear filter that is excited with white noise. The extracted parameters can then be quantized, coded and multiplexed into a bitstream.
== References ==

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Haruna Tunnel (榛名（はるな）トンネル) is a tunnel on JR East-Joetsu Shinkansen line in Japan that runs from Nakazato-cho, Takasaki city to Kawashima, Shibukawa city, in Gunma prefecture with approximate length of 15.350 km. It was completed and opened in 1981.
Excavation was extremely difficult due to the poor geology consisting of volcanic mud flow sediments and water inflow reaching a maximum of 110 t/min, so injection, two-stage silot, and pressurization methods were used in combination. The discharge of tunnel water also affected the ground surface, causing a decrease and depletion of well water, irrigation water, and surface water. In addition, on July 20, 1978, a 30-meter-wide cave-in occurred in the Yamakoda area of Haibuto-Mura. The fields and the Arai-Shimomurota line of Gunma Prefectural Road No. 154 were engulfed, and a large amount of earth and sand flowed into the tunnel directly below (Shimo-Arai construction area).
== See also ==
List of tunnels in Japan
Seikan Tunnel Tappi Shakō Line
Sakhalin–Hokkaido Tunnel
Bohai Strait tunnel
== References ==
== External links ==
Gov. maps.gsi.go.jp
Mapion maps
Haruna Tunnel (in Japanese)

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The Hayes similitude principle enabled aerodynamicists to take the results of one series of tests or calculations and apply them to the design of an entire family of similar configurations where neither tests nor detailed calculations are available.
The similitude principle was developed by Wallace D. Hayes, a pioneer in hypersonic flow, which is considered to begin at about five times the speed of sound, or Mach 5, and is described in his classic book Hypersonic Flow Theory co-written with Ronald Probstein and first published in 1959.
The behavior of the physical processes in actual problems is affected by so many physical quantities that a complete mathematical description thereof is usually very difficult and sometimes practically impossible due to the complicated nature of the phenomena. We know from experience that if two systems are geometrically similar there usually exists some kind of similarity under certain conditions, such as kinematic similarity, dynamic similarity, thermal similarity, and similarity of concentration distribution, and that if similarity conditions are satisfied we can greatly reduce the number of independent variables required to describe the behavior of the process. In this way, we can systematically understand. describe, and even predict the behavior of physical processes in real problems in a relatively simple manner. This principle is known as principle of similitude. Dimensional analysis is a method of deducing logical groupings of the variables, through which we can describe similarity criteria of the processes.
Physical quantities such as length [L], mass [M], time [T], and temperature are dimensional quantities and the magnitude of each quantity can be described by multiples of the unit of each dimension namely m, kg, s, and K, respectively. Through experience, we can select a certain number of fundamental dimensions, such as those mentioned above, and express all other dimensional quantities in terms of products of powers of these fundamental dimensions. Furthermore, in describing the behavior of physical processes, we know that there is an implicit principle that we cannot add or subtract physical quantities of different dimensions. This means that the equations governing physical processes must be dimensionally consistent and each term of the equation must have the same dimensions. This principle is known as the principle of dimensional homogeneity.
(courtesy: Book: Mass transfer : from fundamentals to modern industrial applications, Publisher: Weinheim : WILEY-VCH, 2006.
== References ==
== External links ==
Wallace Hayes, Pioneer of Supersonic Flight, Princeton University obituary
Wallace Hayes, 82, Aeronautics Expert, Dies, The New York Times obituary
Wallace D. Hayes Memorial Tributes: National Academy of Engineering, Volume 1, pp. 151–156.

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Health and usage monitoring systems (HUMS) is a generic term given to activities that utilize data collection and analysis techniques to help ensure availability, reliability and safety of vehicles. Activities similar to, or sometimes used interchangeably with, HUMS include condition-based maintenance (CBM) and operational data recording (ODR). This term HUMS is often used in reference to airborne craft and in particular rotor-craft – the term is cited as being introduced by the offshore oil industry after a commercial Chinook crashed in the North Sea, killing all but one passenger and one crew member in 1986.
HUMS technology and regulation continues to be developed.
HUMS are now used not only for safety but for a number of other reasons including
Maintenance: reduced mission aborts, fewer instances of aircraft on ground (AOG), simplified logistics for fleet deployment
Cost: “maintain as you fly” maintenance flights are not required. Performing repairs when the damage is minor increases the aircraft mean time before failure (MTBF) and decreases the mean time to repair (MTTR)
Operational: improved flight safety, mission reliability and effectiveness
Performance: improved aircraft performance and reduced fuel consumption
Recent advances in the technology include predictive algorithms providing Remaining Useful Life estimates of components and automated wireless data transfer from the aircraft via WiFi or Cellular.
== References ==
== External links ==
United Electronic Industries [1]
BAE Systems [2]
GE Aviation [3]
GPMS Foresight [4]

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Heated hoses are hoses used for transporting liquids or molten materials where integral heat is needed for temperature control. Heated hoses are suitable for environments from -40°C to 80°C and can be used in explosion-proof zones 1/21 and 2/22, if required. Heated hose are generally specified by required inside diameter, working pressure, operating conditions, voltage, temperature sensor and hose fitting.
== Usage ==
Heated hoses are used in bonding technology, filling and dosing systems, medical technology, chemical, pharmaceutical and food industry, extruder applications, and research & development. The heated hoses are used wherever a liquid, viscous or melted medium has to be transported from one place to another, e.g. chocolate, jelly or hotmelt. In most applications, the temperature of the medium needs to remain constant at a specified value irrespective of variations in ambient temperature. Several constructions are available.
== Overview ==
A heated hose consists of a flexible hose, through which the media is pumped. This hose determines the resistance against temperature and chemicals. A heating element is wrapped on the hose and then it is covered with insulation material. Possible insulation materials are Polyamid, steel wire or silicone. The heating element contains a heat sensor. Fittings and fixtures can vary with the application.
Heated hoses are now available for use around the home and farm. Commonly used on farms to get water to livestock in northern climates during the winter.
== See also ==
Heating element
== References ==
== External links ==
Winding of heating element on inner element of a heated hose

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A heating plant, also called a physical plant, or steam plant, generates thermal energy in the form of steam for use in district heating applications. Unlike combined heat and power installations which produce thermal energy as a by-product of electricity generation, heating plants are dedicated to generating heat for use in various processes.
Heating plants are commonly used at hospital or university campuses, military bases, office tower complexes, and public housing complexes. The plant will generate steam which is distributed to each building where it is used to make domestic hot water for human consumption, heating hot water in the case of hydronic heating systems, air conditioning through the use of absorption refrigeration units, air heating in HVAC units, humidification, industrial laundry systems, or sterilization at hospitals. The steam may be sold to each customer and billed through the use of a steam flow meter.
They feature boilers, either water tube or fire tube, which generate steam for various uses and demands. The plant also hosts all of the boiler auxiliaries such as water treatment equipment, air handling, fuel handling, controls, instrument air, and various other plant systems which support the production of steam.
The heating plant can use different fuels:
Natural gas
Heating oil
Biomass
Coal
Refuse
== Notable heating plants ==
Central Heating Plant, Washington, D.C., US
Heating plant and main controls cabin, Florence, Italy
Western Kentucky University Heating Plant, Kentucky, US
== See also ==
Combined heat and power
Cogeneration
District heating
Power station
== References ==

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Heatwork is the combined effect of temperature and time. It is important to several industries:
Ceramics
Glass and metal annealing
Metal heat treating
While the concept of heatwork is taught in material science courses it is not a defined measurement or scientific concept.
Pyrometric devices can be used to gauge heat work as they deform or contract due to heatwork to produce temperature equivalents. Within tolerances, firing can be undertaken at lower temperatures for a longer period to achieve comparable results. When the amount of heatwork of two firings is the same, the pieces may look identical, but there may be differences not visible, such as mechanical strength and microstructure.
== References ==
== External links ==
Temperature equivalents table & description of Bullers Rings.
Temperature equivalents table Archived 2011-04-27 at the Wayback Machine & description of Nimra Cerglass pyrometric cones. Archived 2011-04-23 at the Wayback Machine
Temperature equivalents table & description of Orton pyrometric cones. Archived 2012-04-15 at the Wayback Machine
Temperature equivalents table of Seger pyrometric cones.
Temperature Equivalents, °F & °C Archived 2009-01-06 at the Wayback Machine for Bullers Ring.

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A hoop gun is a gun production technique that uses multiple layers of tubes to form a built-up gun. The innermost tube has one or more extra tubes wrapped around the main tube. These outer tubes are preheated before they are slid into position. As the outer tubes cool they naturally contract. This pre-stresses the main tube so it can withstand greater internal pressures.
== References ==
US Navy 14-inch Gun

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In engineering, a housing or enclosure is a container, a protective exterior (e.g. shell) or an enclosing structural element (e.g. chassis or exoskeleton) designed to enable easier handling, provide attachment points for internal mechanisms (e.g. mounting brackets for electrical components, cables and pipings), maintain cleanliness of the contents by shielding dirt/dust, fouling and other contaminations, or protect interior mechanisms (e.g. delicate integrated electrical fittings) from structural stress and/or potential physical, thermal, chemical, biological or radiational damages from the surrounding environment. Housing may also be the body of a device, vital to its function.
== Description ==
Housing is an exterior case or enclosure used to protect an interior mechanism. The housing prevents the interior mechanism from being fouled by outside debris. It may also have integrated fittings or brackets to keep internal components in place; sometimes a housing is the body of the device, vital to its function.
== Design ==
Housings are most commonly made of metal or plastic. The design of housing is specific to the item and its use. Housing may provide a number of functions.
=== Contamination control ===
Housing prevents the interior mechanism from being fouled by outside debris. Housings are sometimes made watertight, especially when the interior mechanisms contain electronics.
=== Containment ===
Housings are commonly used to protect gearboxes, where the housing also is responsible for containing the lubricant. Housings can also play a safety role, by providing a barrier between people and dangerous or fast-moving mechanisms.
=== Interface ===
Housing may need to provide a user interface for the internal devices, such as for televisions and video game controllers.
=== Decoration ===
Housing may include decorative elements. When these elements are removable and replaceable panels, they may be known as faceplates. Interchangeable faceplates provide a method to update the cosmetics of the housing without replacing the entire enclosure.
== See also ==
Enclosure (electrical)
PC case
Gear housing
Junction box, a housing for electrical components
Electronic packaging
== References ==

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Human Factors in Engineering and Design is an engineering textbook, currently in its seventh edition. First published in 1957 by Ernest J. McCormick, the book is considered a classic in human factors and ergonomics, and one of the best-established texts in the field. It is frequently taught in upper-level and graduate courses in the U.S., and is relied on by practicing human factors and ergonomics professionals.
The text is divided into six sections: Introduction; Information Input; Human Output and Control; Work Space and Arrangement; Environment; and Human Factors: Selected Topics.
== See also ==
Anthropometry
Industrial and organizational psychology
== References ==

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Hydride vapour-phase epitaxy (HVPE) is an epitaxial growth technique often employed to produce semiconductors such as GaN, GaAs, InP and their related compounds, in which hydrogen chloride is reacted at elevated temperature with the group-III metals to produce gaseous metal chlorides, which then react with ammonia to produce the group-III nitrides. Carrier gasses commonly used include ammonia, hydrogen and various chlorides.
HVPE technology can significantly reduce the cost of production compared to the most common method of vapor deposition of organometallic compounds (MOCVD). Cost reduction is achieved by significantly reducing the consumption of NH3, cheaper source materials than in MOCVD, reducing the capital equipment costs, due to the high growth rate.
Developed in the 1960s, it was the first epitaxial method used for the fabrication of single GaN crystals.
Hydride vapour-phase epitaxy (HVPE) is the only III–V and III–N semiconductor crystal growth process working close to equilibrium. This means that the condensation reactions exhibit fast kinetics: one observes immediate reactivity to an increase of the vapour-phase supersaturation towards condensation. This property is due to the use of chloride vapour precursors GaCl and InCl, of which dechlorination frequency is high enough so that there is no kinetic delay. A wide range of growth rates, from 1 to 100 micrometers per hour, can then be set as a function of the vapour-phase supersaturation. Another HVPE feature is that growth is governed by surface kinetics: adsorption of gaseous precursors, decomposition of ad-species, desorption of decomposition products, surface diffusion towards kink sites. This property is of benefit when it comes to selective growth on patterned substrates for the synthesis of objects and structures exhibiting a 3D morphology. The morphology is only dependent on the intrinsic growth anisotropy of crystals. By setting experimental growth parameters of temperature and composition of the vapour phase, one can control this anisotropy, which can be very high as growth rates can be varied by an order of magnitude. Therefore, we can shape structures with various novel aspect ratios. The accurate control of growth morphology was used for the making of GaN quasi-substrates, arrays of GaAs and GaN structures on the micrometer and submicrometer scales, GaAs tips for local spin injection. Fast dechlorination property is also used for the VLS growth of GaAs and GaN nanowires with exceptional length.
== References ==

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Hydrogen darkening is a physical degradation of the optical properties of glass. Free hydrogen atoms are able to bind to the SiO2 silica glass compound forming hydroxyl (OH)—a chemical compound that interferes with the passage of light through the glass.
The problem is particularly relevant to fiber-optic cables—particularly in oil and gas wells where fiber optic cables are used for distributed temperature sensing (DTS). Hydrogen can be present due to the cracking of hydrocarbons in the well. The darkening of the fiber can distort the DTS reading and possibly render the DTS system inoperable due to the optical loss budget being exceeded.
To prevent this, coatings such as carbon are applied to the fiber, and hydrogen capturing gels are used to buffer the fiber and other proprietary techniques may be used to prevent hydrogen atoms from reaching the glass fiber via the cable sheath.
== References ==

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IEC 60228 is the International Electrotechnical Commission (IEC)'s international standard on conductors of insulated cables. As of 2023 the current version is Third Edition 2004-11
Among other things, it defines a set of standard wire cross-sectional areas:
In engineering applications, it is often most convenient to describe a wire in terms of its cross-section area, rather than its diameter, because the cross section is directly proportional to its strength and weight, and inversely proportional to its resistance. The cross-sectional area is also related to the maximum current that a metallic wire can carry safely.
This document is one considered fundamental in that it does not contain reference to any other standard.
== Description ==
The document describes several aspects of the conductors for electrical cables
=== Class ===
This refers to the flexibility and thermal effects i.e temperature of a conductor.
Class 1: Solid conductor
Class 2: Stranded conductor intended for fixed installation
Class 5: Flexible conductor
Class 6: Very Flexible conductor
=== Size ===
The nominal (see below) cross-sectional area for standard conductors including the following:
Class 2: Minimum number of strands required to make particular conductor size
Class 5 and 6: Maximum diameter of any component strand of the conductor
=== Resistance ===
The maximum permissible resistance per unit length (in ohms per kilometre – Ω/km) of each conductor size, class and type (both plain copper and metal coated)
== Purpose of the document ==
This document and its precursors were created due to a need for a standard definition of cable conductor size. The main problem being that not all copper has the same resistivity value, so, for example, a 4 mm2 conductor from two different suppliers may have different resistance values. Instead this document describes conductors by their nominal size, determined by resistance rather than physical dimensions. This is a key distinction as it makes a standardized definition of conductors based solely on their electrical characteristics.
Almost all characteristics of conductors, resistance, current carrying capacity etc. are dependent on the physical dimensions of the conductor. However this document allows an easy reference whereby the standard conductor sizes and reference to physical dimensions are maintained but given an exact meaning in terms of the electrical characteristics of a conductor.
== Footnotes ==
== See also ==
Circular mil, Unusual unit used as the North American Electrical industry standard for wires larger than 4/0.
American wire gauge (AWG), used primarily in the US and Canada
Standard wire gauge (SWG), the British imperial standard BS 3737, superseded by the metric.
Stubs Iron Wire Gauge
Jewelry wire gauge
Body jewelry sizes
Electrical wiring
Number 8 wire, a term used in the New Zealand vernacular
== References ==
== External links ==
"IEC 60228" at International Electrotechnical Commission

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IEC 60929 is an international standard created by the International Electrotechnical Commission and covers electronic ballasts used in AC supplies with voltages up to 1000 V and with operating frequencies at 50 Hz or 60 Hz. The actual operating frequency may deviate from the specified supply frequency.
The standard essentially covers the same material as IEC 60921, but it is considerably more complex due to the high frequency aspect of electronic ballasts. Appendix E of the standard defines the DALI, which specifies how ballasts are controlled.
== References ==
== External links ==
"IEC 60929" at International Electrotechnical Commission

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IEC/EN 62061, ”Safety of machinery: Functional safety of electrical, electronic and programmable electronic control systems”, is the machinery specific implementation of IEC/EN 61508. It provides requirements that are applicable to the system level design of all types of machinery safety-related electrical control systems and also for the design of non-complex subsystems or devices.
The risk assessment results in a risk reduction strategy which in turn, identifies the need for safety-related control functions. These functions must be documented and must include:
Functional requirements specification
Safety integrity requirements specification
The functional requirements include details like frequency of operation, required response time, operating modes, duty cycles, operating environment, and fault reaction functions. The safety integrity requirements are expressed in levels called safety integrity level (SIL). Depending on the complexity of the system, some or all of the elements in Table 14 must be considered to determine whether the system design meets the required SIL.
== External links ==
IEC 62061 at International Electrotechnical Commission

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IEC 62264 is an international standard for enterprise control system integration. This standard is based upon ANSI/ISA-95.
== Current parts of IEC 62264 ==
IEC 62264 consists of the following parts detailed in separate IEC 62264 standard documents:
Part 1:2013 Object Models and Attributes of Manufacturing Operations (Second edition 2013-05)
Part 2:2013 Object model attributes (Second edition 2013-06)
Part 3:2016 Activity models of manufacturing operations management (Second edition 2016-12)
Part 4:2015 Objects models attributes for manufacturing operations management integration
Part 5:2016 Business to manufacturing transactions
Publicly Available Specification - Pre-standard Part 6:2016 Messaging Service Model
== References ==
== External links ==
"IEC 62264-1", "IEC 62264-2", "IEC 62264-3", "IEC 62264-4", "IEC 62264-5", "IEC 62264-6" at International Electrotechnical Commission

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IEC Technical Committee 57 is one of the technical committees of the International Electrotechnical Commission (IEC). TC 57 is responsible for development of standards for information exchange for power systems and other related systems including Energy Management Systems, SCADA, distribution automation & teleprotection.
== Working groups ==
TC 57 consists of several working groups, each of which is responsible for development of standards within its domain. The active working groups are listed below.
== External links ==
IEC TC 57
IEC TC 57 WGs

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title: "IEEE Heinrich Hertz Medal"
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The IEEE Heinrich Hertz Medal was a science award presented by the IEEE for outstanding achievements in the field of electromagnetic waves. The medal was named in honour of German physicist Heinrich Hertz, and was first proposed in 1986 by IEEE Region 8 (Germany) as a centennial recognition of Hertz's work on electromagnetic radiation theory from 1886 to 1891. The medal was first awarded in 1988, and was presented annually until 2001. It was officially discontinued in November 2009.
== Recipients ==
1988: Hans-Georg Unger (Technical University at Brunswick, Germany) for outstanding merits in radio-frequency science, particularly the theory of dielectric wave guides and their application in modern wide-band communication.
1989: Nathan Marcuvitz (Polytechnic University of New York, United States) for fundamental theoretical and experimental contributions to the engineering formulation of electromagnetic field theory.
1990: John D. Kraus (Ohio State University, United States) for pioneering work in radio astronomy and the development of the helical antenna and the corner reflector antenna.
1991: Leopold B. Felsen (Polytechnic University of New York, United States) for highly original and significant developments in the theories of propagation, diffraction and dispersion of electromagnetic waves.
1992: James R. Wait (University of Arizona, United States) for fundamental contributions to electromagnetic theory, to the study of propagation of Hertzian waves through the atmosphere, ionosphere and the Earth, and to their applications in communications, navigation and geophysical exploration.
1993: Kenneth Budden (Cavendish Laboratory, University of Cambridge, United Kingdom) for major original contributions to the theory of electromagnetic waves in ionized media with applications to terrestrial and space communications.
1994: Ronald N. Bracewell (Stanford University, United States) for pioneering work in antenna aperture synthesis and image reconstruction as applied to radioastronomy and to computer-assisted tomography.
1995: Jean van Bladel (Ghent University, Belgium) for major contributions in fundamental electromagnetic theory and its application to electrical engineering.
1996: Martin A. Uman (University of Florida, United States) for outstanding contributions to the understanding of lightning electromagnetics and its application to lightning detection and protection.
1997: Owen Storey (Stanford University, United States) for discovering the field-aligned paths of Hertzian-wave whistlers generated by lightning, thus discovering the Earth's magnetosphere.
1998: Chen To Tai (University of Michigan, United States) for outstanding contributions to electromagnetic and antenna theory and the development and application of Green's dyadics.
1999: Akira Ishimaru (University of Washington, United States) or fundamental contributions to the theories and applications of wave propagation and scattering in random media and backscattering enhancement.
2000: Arthur A. Oliner (Polytechnic University of New York, United States) for contributions to the theory of guided waves and antennas.
2001: Adrianus de Hoop (Delft University of Technology, Netherlands) for fundamental contributions to the theory of reciprocity and to the understanding of electromagnetic wave propagation layered in media.
== See also ==
List of physics awards
== References ==
== External links ==
IEEE Heinrich Hertz Medal

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Idiot-proof refers to the process by which human error is minimized with designs that are easy to understand. This involves finding the causes of misuse, which can improve safety.
Idiot-proof design originated on the basis of safety, where the designer needed to predict, and hence prevent any possible danger of the misuse of the product, no matter how “idiotic”.
As a result, this approach has shaped many different forms of idiot-proofing that now appear in various industries, technologies, and routine tasks.
Two distinct definitions exist in the concept of idiot-proofing: mistakes and slips. When an error happens in decision making is called a mistake, but if it happens in procedure it is called a slip. Idiot-proofing is also known as “mistake-proofing” or “error-proofing” where its objective is to prevent mistakes and slips.
Idiot-proof is similar to the also known as the Japanese concept of equivalent “poka-yoke”, which refers to mistaking proofing mechanisms that were originally applied to car manufacturing systems the latter was introduced by Japanese engineer Shigeo Shingo to achieve zero defects and completely eliminate quality control inspections.
== History ==
Early approaches to idiot-proofing focused on preventing mistakes during operation by designing systems that made incorrect actions impossible or immediately noticeable. Manufacturing environments used physical guides, sensors, and control mechanisms that stopped a process when an error occurred, ensuring that mistakes could not continue through later steps. Industrial quality programs applied methods such as contact detection, fixed-value checks, and motion-step verification to block incorrect inputs and identify errors at their source before defects were produced. Procedures like source inspection and successive checks were introduced to detect the conditions that lead to mistakes, reflecting a shift toward preventing user error through design rather than relying on correction after the fact.
Research identified routine slips, attention failures, memory lapses, and interruptions as common causes of human error, and idiot-proofing techniques were structured so these errors would not affect the outcome of a task. These systems emphasized clear signals and visible indicators that allowed workers to recognize abnormal conditions quickly during operation. Protective safety features also influenced how users interacted with hazards. Safeguards could change patterns of risk exposure, and accident frequency or severity could vary depending on how users responded to added protective measures.
== Usage ==
While there is no specific idiot-proofing process, many fields use different methods to reduce the likelihood and impact of human error. Whether applied to physical equipment or procedural workflows, the goal is to create conditions where errors are unlikely, immediately visible, or unable to cause serious consequences.
=== Physical and mechanical ===
Idiot-proofing modifies tools, tasks, or the work environment so errors are prevented, revealed early, or rendered harmless. Because many mistakes arise from automatic mental routines, distractions, or misleading cues, idiot-proofing introduces physical guides, warning indicators, and forcing functions that reduce ambiguity and block incorrect actions. These devices often make the right action the only action possible, ensuring errors are caught before they can create defects. The approach simplifies work, reduces mental burden, and supports human limitations rather than fighting them.
=== Computer science ===
Software and hardware emphasize the practice of designing systems that can handle user mistakes without crashing or losing data. As computers began to be used by more people without technical backgrounds, programs needed to account for incorrect inputs, accidental key presses, or other errors. Idiot-proof design focuses on checking for errors, giving clear messages, choosing safe defaults, and hiding unnecessary system details from users. These features help make technology more reliable, easier to use, and more accessible to people of all skill levels.
=== Procedural safety ===
In call centers, idiot-proofing is used to prevent both agent and consumer fraud. By preventing access to information or actions, mistakes made by people are limited. Customers enter their credit card numbers through their phone keypad, and a masked Dual-Tone Multi-Frequency app captures that information so agents do not have access to that data. The system verifies the number, then plays an automated summary of the charge and records the customer’s verbal confirmation. This “verbal signature” provides strong evidence for the agent and deters fraudulent chargebacks. Both the users and business feel at ease that fraud is automatically prevented.
== Feasibility ==
Several Murphy's law adages claim that idiot-proof systems cannot be made, for example "Nothing is foolproof to a sufficiently talented fool" and "If you make something idiot-proof, someone will just make a better idiot." Along those lines, Douglas Adams wrote in Mostly Harmless, "a common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools".
== See also ==
Defensive design
Hanlon's razor
Hostile architecture
Inherent safety
Murphy's law
Poka-yoke
Unintended consequences
Worst-case scenario
== References ==

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title: "The Heroic Age of American Invention"
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The Heroic Age of American Invention is a science book for children by L. Sprague de Camp, published by Doubleday in 1961. It was reprinted in 1993 by Barnes & Noble under the alternate title The Heroes of American Invention. The book has been translated in Portuguese.
== Summary ==
By "heroic age" the author means the era of American history in which individual initiative and enterprise constituted the primary thread in technical innovation, roughly from the early 19th century until mass production and corporate enterprise outpaced that of the individual around the time of World War I. The story of innovation is told through the biographies and inventions of thirty-two key inventors of the United States' Industrial Revolution, whom de Camp feels were pivotal in converting the country from an agrarian nation to an industrial one.
Some of the inventors spotlighted include Robert L. Stevens, George Westinghouse, Joseph Henry, Samuel Morse, Samuel Colt, Hiram Stevens Maxim, Hudson Maxim, Cyrus McCormick, John Ericsson, William Kelly, Ottmar Mergenthaler, Christopher Latham Sholes, Alexander Graham Bell, Thomas Edison, Elihu Thomson, Nikola Tesla, George Baldwin Selden, Samuel Pierpoint Langley, Wilbur Wright, Orville Wright, Reginald Aubrey Fessenden, Lee de Forest, and Edwin Howard Armstrong.
== Contents ==
I. Invention Comes to America
II. The Heroic Age Begins
III. The Stevenses and Railroading
IV. Henry, Morse, and the Telegraph
V. Colt and Other Gunmakers
VI. McCormick and Farm Machinery
VII. Ericsson and the Modern Warship
VIII. Kelly and Steel Refining
IX. Mergenthaler, Sholes, and Writing Machines
X. Bell and the Telephone
XI. Edison and the Electric Light
XII. Thomson and Alternating-Current Power
XIII. Selden and the Automobile
XIV. Langley, The Wrights, and Flying
XV. Fessenden, De Forest, and Radio
XVI. The End of the Heroic Age
Notes
Bibliography
Index
== References ==

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