id int64 39 79M | url stringlengths 31 227 | text stringlengths 6 334k | source stringlengths 1 150 ⌀ | categories listlengths 1 6 | token_count int64 3 71.8k | subcategories listlengths 0 30 |
|---|---|---|---|---|---|---|
17,350,571 | https://en.wikipedia.org/wiki/Iwahashi%20Zenbei | was a Japanese scientist and optician.
Biography
He was born in Kaizuka, Osaka, in a merchant family, became independent to be an optician, then was interested in natural science and learned scientific methodology and physics from Minagawa Kien, a scholar of I Ching, in Kyoto. He observed movements of the sun, the moon, stars, and developed an instrument to calculate the movements of celestial bodies and tides called Heitengi (平天儀) in 1801 and wrote the theoretical book of astronomy called Heitengi zukai (平天儀図解) in 1802.
Zenbei researched some imported optical instruments, then in 1793, made his first telescope. It had quite a good reputation then he made many telescopes of Galileo type and Kepler type, which widely used among astronomers and feudal rulers. His descendants became telescope makers for four generations.
Zenbei Land, an education center for astronomy and its history named in honor of Zenbei, equipped with a 600 mm diameter newtonian/cassegrain reflector, has been open to public since 1992 by Kaizuka municipal government.
An asteroid 7538 Zenbei was named after him.
References
An Iwahashi's telescope as a historical heritage of Osaka Prefecture
Zenbei Land homepage
1756 births
1811 deaths
Opticians
18th-century Japanese astronomers
People from Kaizuka, Osaka
Telescope manufacturers
19th-century Japanese astronomers | Iwahashi Zenbei | [
"Astronomy"
] | 277 | [
"Telescope manufacturers",
"People associated with astronomy",
"Opticians",
"History of astronomy"
] |
17,351,973 | https://en.wikipedia.org/wiki/Radical%20clock | In chemistry, a radical clock is a chemical compound that assists in the indirect methodology to determine the kinetics of a free-radical reaction. The radical-clock compound itself reacts at a known rate, which provides a calibration for determining the rate of another reaction.
Many organic mechanisms involve intermediates that cannot be identified directly but which are inferred from trapping reactions. When such intermediates are radicals, their lifetimes can be deduced from radical clocks. An alternative, perhaps more direct approach involves generation and isolation of the intermediates by flash photolysis and pulse radiolysis, but such methods are time-consuming and require expensive equipment. With an indirect approach of radical clocks, one can still obtain relative or absolute rate constants without the need for instruments or equipment beyond those normally needed for the reaction being studied.
Theory and technique
Radical clock reactions involve a competition between a unimolecular radical reaction with a known rate constant and a bimolecular radical reaction with an unknown rate constant to produce unrearranged and rearranged products. The rearrangement of an unrearranged radical, U•, proceeds to form R• (the clock reaction) with a known rate constant (kr). These radicals react with a trapping agent, AB, to form the unrearranged and rearranged products UA and RA, respectively.
The yield of the two products can be determined by gas chromatography (GC) or nuclear magnetic resonance (NMR). From the concentration of the trapping agent, the known rate constant of the radical clock, and the ratio of the products, the unknown rate constant can be indirectly established.
If a chemical equilibrium exists between U• and R•, the rearranged products are dominant. Because the unimolecular rearrangement reaction is first order and the bimolecular trapping reaction is second order (both irreversible), the unknown rate constant (kR) can be determined by:
Clock rates
The driving force behind radical clock reactions is their ability to rearrange. Some common radical clocks are radical cyclizations, ring openings, and 1,2-migrations. Two popular rearrangements are the cyclization of 5-hexenyl and the ring-opening of cyclopropylmethyl:
5-hexenyl radical undergoes cyclization to produce a five-membered ring because this is entropically and enthalpically more favored than the six-membered ring possibility. The rate-constant for this reaction is 2.3×105 s−1 at 298 K.
Cyclopropylmethyl radical undergoes a very rapid ring opening rearrangement that relieves the ring strain and is enthalpically favorable. The rate-constant for this reaction is 8.6×107 s−1 at 298 K.
In order to determine absolute rate constants for radical reactions, unimolecular clock reactions need to be calibrated for each group of radicals such as primary alkyls over a range of time. Through the usage of EPR spectroscopy, the absolute rate constants for unimolecular reactions can be measured with a variety of temperatures. The Arrhenius equation can then be applied to calculate the rate constant for a specific temperature at which the radical clock reactions are conducted.
When using a radical clock to study a reaction, there is an implicit assumption that the rearrangement rate of the radical clock is the same as when the rate of that rearrangement reaction rate is determined. A theoretical study of the rearrangement reactions of cyclobutylmethyl and of 5-hexenyl in a variety of solvents found that their reaction rates were only very slightly affected by the nature of the solvent.
The rates of radical clocks can be adjusted to increase or decrease by what types of substituents are attached to the radical clock. In the figure below, the rates of the radical clocks are shown with a variety of substituents attached to the clock.
By selecting among the general classes of radical clocks and the specific substituents on them, one can be chosen with a rate-constant suitable for studying reactions having a wide range of rates. Reactions having rates ranging from 10−1 to 1012 M−1 s−1 have been studied using radical clocks.
Examples of use
Radical clocks are used in reduction of alkyl halides with sodium naphthalenide, reaction of enones, the Wittig rearrangement, reductive elimination reactions of dialkylmercury compounds, dioxirane dihydroxylations, and electrophilic fluorinations.
References
External links
RADICAL CLOCKS: MOLECULAR STOPWATCHES FOR TIMING RADICAL REACTIONS
Radical Clock Reactions
Free radicals
Chemical kinetics | Radical clock | [
"Chemistry",
"Biology"
] | 974 | [
"Chemical reaction engineering",
"Free radicals",
"Senescence",
"Biomolecules",
"Chemical kinetics"
] |
17,353,312 | https://en.wikipedia.org/wiki/Cement%20render | Cement render or cement plaster is the application of a mortar mix of sand and cement, (optionally lime) and water to brick, concrete, stone, or mud brick. It is often textured, colored, or painted after application. It is generally used on exterior walls but can be used to feature an interior wall. Depending on the 'look' required, rendering can be fine or coarse, textured or smooth, natural or colored, pigmented or painted.
The cement rendering of brick, concrete and mud houses has been used for centuries to improve the appearance (and sometimes weather resistance) of exterior walls. It can be seen in different forms all over southern Europe. Different countries have their own styles and traditional colors. In the United Kingdom, cement is optional. In other countries, lime is optional. The cement in render hydrates the same way it does in concrete.
Render finishes
Different finishes can be created by using different tools such as trowels, sponges, or brushes. The art in traditional rendering is (apart from getting the mix right) the appearance of the top coat. Different tradesmen have different finishing styles and are able to produce different textures and decorative effects. Some of these special finishing effects may need to be created with a thin finishing top coat or a finishing wash.
Traditional rendering
Cement render consists of 6 parts clean sharp fine sand, 1 part cement, and 1 part lime in some parts of the world. The lime makes the render more workable and reduces cracking when the render dries. Any general purpose cement can be used. Various additives can be added to the mix to increase adhesion. Coarser sand is used in the base layer and slightly finer sand in the top layer.
The application process resembles the process of applying paint. To ensure adhesion, the surface to be rendered is initially hosed off to ensure it is free of any dirt and loose particles. Old paint or old render is scraped away. The surface is roughened to improve adhesion. For large areas, vertical battens are fixed to the wall every 1 to 1.5 meters, to keep the render flat and even.
Acrylic rendering
There is also a wide variety of premixed renders commercially available for different situations. Some have a polymer additive added to the traditional cement, lime and sand mix for enhanced water resistance, flexibility and adhesion.
Acrylic premixed renders have superior water resistance and strength. They can be used on a wider variety of surfaces than cement render, including concrete, cement blocks, and AAC concrete paneling. These acrylic modified renders may still be too brittle and cannot be applied over substrates like fiber cement sheeting, as they will crack on the joints and can allow water to enter the sheet and cause delamination of the coatings. The newer technology polymer exterior cladding such as expanded polystyrene (EPS) can have these acrylic modified renders applied to them with the inclusion of an alkali resistant mesh encapsulated between the render coats. Some premixed acrylic renders have a smoother complexion than traditional renders. There are also many various acrylic-bound pigmented 'designer' finishing coats that can be applied over acrylic render. Various finishes, patterns and textures are possible such as sand, sandstone, marble, stone, stone chip, lime wash or clay like finishes. There are stipple, glistening finishes, and those with enhanced water resistance and antifungal properties. Depending upon the product, they can be rolled, troweled or sponged on. A limited number can also be sprayed on. Acrylic renders usually take only 2 days to dry and thus much faster than the usual 28 days for traditional render.
A disadvantage of acrylic render vs. traditional rendering is that acrylic render lacks the sustainability and environmental compatibility of traditional cement-and-mineral render. All buildings have a finite lifetime, and their materials will eventually be either recycled or absorbed into the environment. As acrylics are synthetic polymers, they do not break down by natural weathering the same way that a cement, sand, and lime mixture will, and so will persist in the natural environment for much longer as synthetic chemical compounds that have unknown long-term effects on ecosystems. Also, the application and drying process of solvent based acrylic resin render involves the atmospheric evaporation of pollutant solvents—necessary for the application of the resin—which are hazardous to the health of humans and of many organisms on which humans depend. Synthetic polymers such as acrylic are manufactured from chemical feedstocks such as acetone, hydrogen cyanide, ethylene, isobutylene, and other petroleum derivatives. The polymer products cannot be fully recycled (using present technology or any that can be confidently expected to be developed), so new raw materials, taken from the finite and diminishing supply of raw natural resources, must always be put into their manufacture, making the process unsustainable. Traditional cement-based render does not have these problems, making it an arguably better choice in many cases, despite its working limitations. Using Waterborne resins will not have these disadvantages.
See also
Exterior insulation finishing system
Harling (wall finish)
Lath and plaster
Pargeting
Plaster
Plasterwork
Polished plaster
Siding
Stucco
Tadelakt
References
Further reading
Construction
Wallcoverings
Building materials
Plastering
nl:Pleister (bouw) | Cement render | [
"Physics",
"Chemistry",
"Engineering"
] | 1,110 | [
"Building engineering",
"Coatings",
"Architecture",
"Construction",
"Materials",
"Plastering",
"Matter",
"Building materials"
] |
17,353,426 | https://en.wikipedia.org/wiki/Bacampicillin | Bacampicillin (INN) is a penicillin antibiotic. It is a prodrug of ampicillin with improved oral bioavailability.
It was sold under the brand names Spectrobid (Pfizer) and Penglobe (AstraZeneca).In 2015, Pfizer discontinued Spectrobid, and no generic manufacturer has taken over production. Bacampicillin is thus unavailable in the United States, and is no longer FDA approved.
Synthesis
Semi-synthetic antibiotic related to penicillin.
The relatively small chemical difference between ampicillin and benzylpenicillin not only allows for substantial oral activity but also results in a substantial broadening of antimicrobial spectrum so as to allow for use against many Gram-negative bacteria. Many devices have been employed in order to enhance still further the oral absorption of ampicillin. Bacampicillin is a prodrug of ampicillin designed for this purpose.
An azidopenicillin sodium salt (1) is reacted with mixed carbonate ester 2 (itself prepared from acetaldehyde and ethyl chloroformate) to give ester 3. Reduction of the azido linkage with hydrogen and a suitable catalyst produces bacampillin (4). Both enantiomers are active. The drug is rapidly absorbed from the gastrointestinal tract and is quickly cleaved by serum esterases to bioactive ampicillin, acetaldehyde, and ethanol.
References
Penicillins
Carboxylate esters
Prodrugs
Ethyl esters | Bacampicillin | [
"Chemistry"
] | 326 | [
"Chemicals in medicine",
"Prodrugs"
] |
17,353,952 | https://en.wikipedia.org/wiki/List%20of%20stars%20for%20navigation | Fifty-seven navigational stars and additionally the star Polaris are given a special status in the field of celestial navigation. Of the approximately six thousand stars visible to the naked eye under optimal conditions, these selected stars are among the brightest and span thirty-eight constellations of the celestial sphere from the declination of −70° to +89°. Many of the selected stars were named in antiquity by the Babylonians, Greeks, Romans, and Arabs.
The star Polaris, often called either the "Pole Star" or the "North Star", is treated specially due to its proximity to the north celestial pole. When navigating in the Northern Hemisphere, a simple and quick technique can be used with Polaris to determine the observers latitude or, for larger maritime vessels can be used to calculate any gyrocompass error that may exist. The other fifty-seven selected stars have daily positions given in nautical almanacs, aiding the navigator in efficiently performing observations on them. A second group of 115 "tabulated stars" can also be used for celestial navigation, but are often less familiar to the navigator and require extra calculations.
Although Polaris can quickly and simply give a solution for latitude in the northern hemisphere, it can not participate in giving a position fix including longitude - it is for this reason it is excluded from the list of 57 primary navigational stars, each of which can be used to produce (in conjunction with each other, known time in relation to the prime meridian and a set of sight reduction tables) an actual latitudinal and longitudinal positional fix.
For purposes of identification, the positions of navigational stars — expressed as declination and sidereal hour angle — are often rounded to the nearest degree. In addition to tables, star charts provide an aid to the navigator in identifying the navigational stars, showing constellations, relative positions, and brightness.
In practical use for sight reductions whilst at sea, tables can further assist a navigator by giving approximate altitudes (angles above the horizon) and azimuths (degrees as read from the compass) from an assumed or estimated position, usually helping to quickly determine the location and then quickly identify a particular navigational star that may be useful for a sight reduction.
Background
Under optimal conditions, approximately six thousand stars are visible to the naked eye of an observer on Earth. Of these, fifty-eight stars are known in the field of navigational astronomy as "selected stars", including nineteen stars of the first magnitude, thirty-eight stars of the second magnitude, and Polaris. The selection of the stars is made by His Majesty's Nautical Almanac Office and the US Naval Observatory, in the production of the yearly Nautical Almanac which the two organizations have published jointly since 1958. Criteria in the choice of stars includes their distribution across the celestial sphere, brightness, and ease of identification. Information for another 115 stars, known as "tabulated stars", is also available to the navigator. This list provides information on the name, approximate position in the celestial sphere, and apparent magnitude of the 58 selected stars in tabular form and by star charts.
These stars are typically used in two ways by the navigator. The first is to obtain a line of position by use of a sextant observation and the techniques of celestial navigation. Multiple lines of position can be intersected to obtain a position known as a celestial fix. The second typical use of the navigational stars is to determine gyrocompass error by computing the azimuth of a star and comparing it to an azimuth measured using the ship's gyrocompass. Numerous other applications also exist.
Navigators typically refer to stars using one of two naming systems for stars: common names and Bayer's designations. All of the selected stars have had a common name since 1953, and many were named in antiquity by the Arabs, Greeks, Romans, and Babylonians. Bayer's naming convention has been in use since 1603, and consists of a Greek letter combined with the possessive form of the star's constellation. Both names are shown for each star in the tables and charts below.
Each star's approximate position on the celestial sphere is given using the equatorial coordinate system. The celestial sphere is an imaginary globe of infinite size with the Earth at its center. Positions on the celestial sphere are often expressed using two coordinates: declination and sidereal hour angle, which are similar to latitude and longitude on the surface of the Earth. To define declination, the Earth's equator is projected out to the celestial sphere to construct the celestial equator, and declination is measured in degrees north or south of this celestial equator. Sidereal hour angle is a measurement between 0° and 360°, indicating how far west a body is from an arbitrarily chosen point on the celestial sphere called the First Point of Aries. Note that right ascension, as used by astronomers, is 360° minus the sidereal hour angle.
The final characteristic provided in the tables and star charts is the star's brightness, expressed in terms of apparent magnitude. Magnitude is a logarithmic scale of brightness, designed so that a body of one magnitude is approximately 2.512 times brighter than a body of the next magnitude. Thus, a body of magnitude 1 is 2.5125 (~100) times brighter than a body of magnitude 6. The dimmest stars that can be seen through a 200-inch terrestrial telescope are of the 20th magnitude, and very bright objects like the Sun and a full Moon have magnitudes of −26.7 and −12.6 respectively.
Table
The table of navigational stars provides several types of information. In the first column is the identifying index number, followed by the common name, the Bayer designation, and the etymology of the common name. Then the star's approximate position, suitable for identification purposes, is given in terms of declination and sidereal hour angle, followed by the star's magnitude. The final column presents citations to the sources of the data, The American Practical Navigator and the star's entry at the SIMBAD database, a project of the Strasbourg Astronomical Data Center or CDS.
Star charts
Navigators often use star charts to identify a star by its position relative to other stars. References like the Nautical Almanac and The American Practical Navigator provide four star charts, covering different portions of the celestial sphere. Two of these charts are azimuthal equidistant projections of the north and south poles. The other two cover the equatorial region of the celestial sphere, from the declination of 30° south to 30° north. The two equatorial charts are mercator projections, one for the eastern hemisphere of the celestial sphere and one for the western hemisphere. Note that unlike familiar maps, east is shown to the left and west is shown to the right. With this orientation, the navigator can hold the star chart overhead, and the arrangement of the stars on the chart will resemble the stars in the sky.
In the star charts, constellations are labelled with capital letters and indicated by dotted lines collecting their stars. The 58 selected stars for navigation are shown in blue and labelled with their common name, star number, and a Greek letter to indicate their Bayer designation. The additional 115 tabulated stars that can also be used for navigation are shown in red and labelled with a Greek letter to indicate their Bayer designation. Some additional stars not suitable for navigation are also included on the charts to indicate constellations, they are presented as unlabelled small red dots.
Equatorial stars
Equatorial stars of the eastern hemisphere
The equatorial region of the celestial sphere's eastern hemisphere includes 17 navigational stars from Alpheratz in the constellation Andromeda to Denebola in Leo. It also includes stars from the constellations Cetus, Aries, Taurus, Orion, Canis Major and Minor, Gemini, and Hydra. Of particular note among these stars are "the dog star" Sirius, the brightest star in the sky, and four stars of the easily identified constellation Orion.
Equatorial stars of the western hemisphere
The equatorial region of the celestial sphere's western hemisphere includes 13 navigational stars from Gienah in the constellation Corvus to Markab in Pegasus. It also includes stars from the constellations Virgo, Bootes, Libra, Corona Borealis, Scorpio, Ophiuchus, Sagittarius, and Aquila. The variable star Arcturus is the brightest star in this group.
Northern stars
The 11 northern stars are those with a declination between 30° north and 90° north. They are listed in order of decreasing sidereal hour angle, or from the vernal equinox westward across the sky. Starting with Schedar in the constellation Cassiopeia, the list includes stars from the constellations Auriga, the Great and Little Bears, Draco, Lyra and Cygnus. The two brightest northern stars are Vega and Capella.
In the star chart to the right, declination is shown by the radial coordinate, starting at 90° north in the center and decreasing to 30° north at the outer edge. Sidereal hour angle is shown as the angular coordinate, starting at 0° at the left of the chart, and increasing counter-clockwise.
Southern stars
The 18 southern stars are those with a declination between 30° south and 90° south. They are listed in order of decreasing sidereal hour angle, or from the vernal equinox westward across the sky. Starting with Ankaa in the constellation Phoenix, the list includes stars from the constellations Eridanus, Carina, Crux, Centaurus, Libra, Triangulum Australe, Scorpio, Sagittarius, Pavo, and Grus. Canopus, Rigil Kentaurus, Achernar, and Hadar are the brightest stars in the southern sky.
In the star chart to the right, declination is shown by the radial coordinate, starting at 90° south in the center and decreasing to 30° south at the outer edge. Sidereal hour angle is shown as the angular coordinate, starting at 0° at the right of the chart, and increasing clockwise.
Footnotes
Notes
Citations
References
Stars
Navigation
Navigation | List of stars for navigation | [
"Astronomy"
] | 2,092 | [
"Celestial navigation"
] |
17,354,313 | https://en.wikipedia.org/wiki/WidSets | WidSets is a mobile runtime technology, and a mobile service powered by the said technology, based on the Java MIDP 2.0 platform, from the Finnish mobile company Nokia. It is both a widget engine and a widget deployment service where mini-applications called widgets can be uploaded to WidSets servers to be compiled and then automatically deployed to MIDP 2.0 compliant mobile phones running the WidSets client software. The widgets are created using Extensible Markup Language (XML), Cascading Style Sheets (CSS), and Helium scripting language. Widsets is a combined application and service that is similar to what a widget does on a desktop PC, on a wide variety of mobile phones. WidSets are micro-applications intended to perform a single function. WidSets, like widgets, generally rely on some kind of web service to provide information to the user.
WidSets was officially launched in October 2006. It worked on all Java MIDP 2.0 phones, including non-Nokia ones, and was regarded as a mobile counterpart to Netvibes. The current version is version 2.0.0 for both the client and the SDK. In June 2009, Nokia announced that WidSets is no longer developed, having been replaced by the umbrella Ovi Store.
Example widgets included currency converters, news headlines retrievers and weather forecast information.
References
External links
WidSets Official Website
Mobilise your Web with WidSets – Europe
Mobilise your Web with WidSets – UK
Widget engines
Mobile technology
Nokia services | WidSets | [
"Technology"
] | 330 | [
"nan"
] |
17,354,429 | https://en.wikipedia.org/wiki/Caesium%20nitrate | Caesium nitrate or cesium nitrate is a salt with the chemical formula CsNO3. An alkali metal nitrate, it is used in pyrotechnic compositions, as a colorant and an oxidizer, e.g. in decoys and illumination flares. The caesium emissions are chiefly due to two powerful spectral lines at 852.113 nm and 894.347 nm.
Caesium nitrate prisms are used in infrared spectroscopy, in x-ray phosphors, and in scintillation counters. It is also used in making optical glasses and lenses.
As with other alkali metal nitrates, caesium nitrate decomposes on gentle heating to give caesium nitrite:
Caesium also forms two unusual acid nitrates, which can be described as CsNO3·HNO3 and CsNO3·2HNO3 (melting points 100 °C and 36–38 °C respectively).
References
Caesium compounds
Nitrates
Pyrotechnic oxidizers
Pyrotechnic colorants | Caesium nitrate | [
"Chemistry"
] | 222 | [
"Inorganic compounds",
"Oxidizing agents",
"Inorganic compound stubs",
"Nitrates",
"Salts"
] |
17,355,301 | https://en.wikipedia.org/wiki/Plasma%20confinement | In plasma physics, plasma confinement refers to the act of maintaining a plasma in a discrete volume. Confining plasma is required in order to achieve fusion power. There are two major approaches to confinement: magnetic confinement and inertial confinement.
References
Plasma technology and applications
Fusion power | Plasma confinement | [
"Physics",
"Chemistry"
] | 57 | [
"Plasma physics",
"Plasma technology and applications",
"Fusion power",
"Plasma physics stubs",
"Nuclear fusion"
] |
17,356,047 | https://en.wikipedia.org/wiki/Epicillin | Epicillin (INN) is a penicillin antibiotic. It is not approved by the FDA for use in the United States.
It is an aminopenicillin.
References
Penicillins
Enantiopure drugs | Epicillin | [
"Chemistry"
] | 48 | [
"Stereochemistry",
"Enantiopure drugs"
] |
17,356,800 | https://en.wikipedia.org/wiki/Acid%E2%80%93base%20disorder | Acid–base imbalance is an abnormality of the human body's normal balance of acids and bases that causes the plasma pH to deviate out of the normal range (7.35 to 7.45). In the fetus, the normal range differs based on which umbilical vessel is sampled (umbilical vein pH is normally 7.25 to 7.45; umbilical artery pH is normally 7.18 to 7.38). It can exist in varying levels of severity, some life-threatening.
Classification
An excess of acid is called acidosis or acidemia, while an excess in bases is called alkalosis or alkalemia. The process that causes the imbalance is classified based on the cause of the disturbance (respiratory or metabolic) and the direction of change in pH (acidosis or alkalosis). This yields the following four basic processes:
Mixed disorders
The presence of only one of the above derangements is called a simple acid–base disorder. In a mixed disorder, more than one is occurring at the same time. Mixed disorders may feature an acidosis and alkosis at the same time that partially counteract each other, or there can be two different conditions affecting the pH in the same direction. The phrase "mixed acidosis", for example, refers to metabolic acidosis in conjunction with respiratory acidosis. Any combination is possible, as metabolic acidosis and alkalosis can co exist together.
Calculation of imbalance
The traditional approach to the study of acid–base physiology has been the empirical approach. The main variants are the base excess approach and the bicarbonate approach. The quantitative approach introduced by Peter A Stewart in 1978 is newer.
Causes
There are numerous reasons that each of the four processes can occur (detailed in each article). Generally speaking, sources of acid gain include:
Retention of carbon dioxide
Production of nonvolatile acids from the metabolism of proteins and other organic molecules
Loss of bicarbonate in feces or urine
Intake of acids or acid precursors
Sources of acid loss include:
Use of hydrogen ions in the metabolism of various organic anions
Loss of acid in the vomitus or urine
Gastric aspiration in hospital
Severe diarrhea
Carbon dioxide loss through hyperventilation
Compensation
The body's acid–base balance is tightly regulated. Several buffering agents exist which reversibly bind hydrogen ions and impede any change in pH. Extracellular buffers include bicarbonate and ammonia, while proteins and phosphate act as intracellular buffers. The bicarbonate buffering system is especially key, as carbon dioxide (CO2) can be shifted through carbonic acid (H2CO3) to hydrogen ions and bicarbonate (HCO3−) as shown below.
HCO_3^- + H+ <=> H2CO3 <=> CO2 + H2O
Acid–base imbalances that overcome the buffer system can be compensated in the short term by changing the rate of ventilation. This alters the concentration of carbon dioxide in the blood, shifting the above reaction according to Le Chatelier's principle, which in turn alters the pH. For instance, if the blood pH drops too low (acidemia), the body will compensate by increasing breathing, expelling CO2, and shifting the reaction above to the right such that fewer hydrogen ions are free–thus the pH will rise back to normal. For alkalemia, the opposite occurs.
The kidneys are slower to compensate, but renal physiology has several powerful mechanisms to control pH by the excretion of excess acid or base. In responses to acidosis, tubular cells reabsorb more bicarbonate from the tubular fluid, collecting duct cells secrete more hydrogen and generate more bicarbonate, and ammoniagenesis leads to increased formation of the NH3 buffer. In responses to alkalosis, the kidney may excrete more bicarbonate by decreasing hydrogen ion secretion from the tubular epithelial cells, and lowering rates of glutamine metabolism and ammonia excretion.
References
External links
On-line text at AnaesthesiaMCQ.com
Overview at kumc.edu
Overview at mcgill.ca
Stewart's original text at acidbase.org
Overview at med.utah.edu
Overview at anaesthetist.com
Overview at anst.uu.se
Tutorial at acid-base.com
Online acid–base physiology text
Diagnoses at lakesidepress.com
Interpretation at nda.ox.ac.uk
Acid Base Tutorial
Human homeostasis
Acid–base physiology
Acid–base disturbances
Equilibrium chemistry
Respiratory therapy | Acid–base disorder | [
"Chemistry",
"Biology"
] | 943 | [
"Acid–base physiology",
"Human homeostasis",
"Equilibrium chemistry",
"Homeostasis",
"Acid–base disturbances"
] |
17,357,198 | https://en.wikipedia.org/wiki/Odanacatib | Odanacatib (INN; codenamed MK-0822) is an investigational treatment for osteoporosis and bone metastasis. It is an inhibitor of cathepsin K, an enzyme involved in bone resorption.
The drug was developed by Merck & Co. The phase III clinical trial for this medicine was stopped early after a review showed it was highly effective and had a good safety profile. Merck announced in 2014 that it would apply for regulatory approval in 2015.
In 2016, Merck discontinued development of odanacatib and announced it would not seek regulatory approval after analysis discovered an increased risk of stroke.
This drug was developed at Merck Frosst in Montreal.
References
Abandoned drugs
Cyclopropanes
Trifluoromethyl compounds
Organofluorides
Biphenyls
Nitriles
Enzyme inhibitors | Odanacatib | [
"Chemistry"
] | 178 | [
"Nitriles",
"Drug safety",
"Functional groups",
"Abandoned drugs"
] |
17,359,213 | https://en.wikipedia.org/wiki/Topological%20semigroup | In mathematics, a topological semigroup is a semigroup that is simultaneously a topological space, and whose semigroup operation is continuous.
Every topological group is a topological semigroup.
See also
References
Topological algebra
Topological groups | Topological semigroup | [
"Mathematics"
] | 44 | [
"Algebra stubs",
"Space (mathematics)",
"Topological spaces",
"Fields of abstract algebra",
"Topology",
"Topology stubs",
"Topological groups",
"Topological algebra",
"Algebra"
] |
17,359,307 | https://en.wikipedia.org/wiki/Paratopological%20group | In mathematics, a paratopological group is a topological semigroup that is algebraically a group. In other words, it is a group G with a topology such that the group's product operation is a continuous function from G × G to G. This differs from the definition of a topological group in that the group inverse is not required to be continuous.
As with topological groups, some authors require the topology to be Hausdorff.
Compact paratopological groups are automatically topological groups.
References
Topological groups | Paratopological group | [
"Mathematics"
] | 103 | [
"Space (mathematics)",
"Topological spaces",
"Topology stubs",
"Topology",
"Topological groups"
] |
10,912,431 | https://en.wikipedia.org/wiki/Vibrio%20alginolyticus | Vibrio alginolyticus is a Gram-negative marine bacterium. It is medically important since it causes otitis and wound infection. It is also present in the bodies of animals such as pufferfish, where it is responsible for the production of the potent neurotoxin, tetrodotoxin.
Vibrio alginolyticus are commonly found in aquatic environments. Some strains of V. alginolyticus are highly salt tolerant and commonly found in marine environment. S.I. Paul et al. (2021) isolated and identified many strains of Vibrio alginolyticus from nine marine sponges of the Saint Martin's Island Area of the Bay of Bengal, Bangladesh.
V. alginolyticus was first identified as a pathogen of humans in 1973. It occasionally causes eye, ear, and wound infections. It is a highly salt-tolerant species and can grow in salt concentrations of 10%. Most clinical isolates come from superinfected wounds that become contaminated at the beach. Tetracycline is typically an effective treatment. V. alginolyticus is rare cause of bacteremia in immunocompromised hosts.
Biochemical characteristics of V. alginolyticus
Colony, morphological, physiological, and biochemical characteristics of Vibrio alginolyticus are shown in the Table below.
Note: + = Positive, – =Negative
References
External links
Type strain of Vibrio alginolyticus at BacDive - the Bacterial Diversity Metadatabase
Vibrionales
Bacteria described in 1961
Marine microorganisms | Vibrio alginolyticus | [
"Biology"
] | 332 | [
"Marine microorganisms",
"Microorganisms"
] |
10,913,480 | https://en.wikipedia.org/wiki/List%20of%20Brazilian%20states%20by%20life%20expectancy | There are 26 States of Brazil, or Estados in Portuguese, which are the federal states of Brazil, plus the Federal District which holds the capital city, Brasília. The second number in bold corresponds to the map. This and the figures below are based on 2022 estimate data, the life expectancy at birth for women being 81.23 years and for men 74.30, with an average of 77.76 years expected at birth, both sexes combined.
Global Data Lab (2019–2022)
Data source: Global Data Lab
See also
List of South American countries by life expectancy
Brazil
States of Brazil
List of subnational entities
List of Latin American subnational entities by HDI
References
External links
ibge.gov.br
Brazil, life expectancy
LIfe expectancy
Brazil
States by life expectancy | List of Brazilian states by life expectancy | [
"Biology"
] | 163 | [
"Senescence",
"Life expectancy"
] |
10,914,584 | https://en.wikipedia.org/wiki/Luciano%20Maiani | Luciano Maiani (born 16 July 1941) is a Sammarinese physicist. He is best known for his prediction of the charm quark with Sheldon Glashow and John Iliopoulos (the "GIM mechanism").
Academic history
In 1964 Luciano Maiani received his degree in physics and he became a research associate at the Istituto Superiore di Sanità in Italy. During that same year he collaborated with Raoul Gatto's theoretical physics group at the University of Florence. He crossed the Atlantic in 1969 to do a post-doctoral fellowship at Harvard University's Lyman Laboratory of Physics. In 1976 Maiani became a professor of theoretical physics at the University of Rome, however he traveled widely during this period, holding visiting professorships at the École normale supérieure of Paris (1977) and CERN (1979–1980 and 1985–1986). Maiani also took an interest in the direction of particle physics research start on CERN's Scientific Policy Committee from 1984 to 1991. Then, in 1993, he became president of Italy's Istituto Nazionale di Fisica Nucleare (INFN). From 1993 to 1996 Maiani served as a scientific delegate in CERN council and then as that council's president in 1997. Thereafter he became director general of CERN, serving from 1 January 1999 through the end of 2003. From 1995 to 1997 Maiani chaired the Italian Comitato Tecnico Scientifico, Fondo Ricerca Applicata. At the end of 2007 he was proposed as president of Consiglio Nazionale delle Ricerche, but his nomination was suspended temporally after he signed a letter criticizing the rector of 'La Sapienza' University in Rome, who invited Pope Benedict XVI to give a lectio magistralis in 2008. However he became the President of CNR since 2008.
As of September 2020, he is a member of the Italian Aspen Institute.
Research
Luciano Maiani has authored over 100 scientific publications on the theory of elementary particles often with several co-authors. In 1970 he predicted the charm quark in a paper with Glashow and Iliopoulos which was later discovered at SLAC and Brookhaven in 1974 and led to a Nobel Prize in Physics for the discoverers. Working with Guido Altarelli in 1974 they explained that the observed octet enhancement in weak non-leptonic decays was due to a leading gluon exchange effect in quantum chromodynamics. They later extended this effect to describe the weak non-leptonic decays of charm and bottom quarks as well and also produced a parton model description of heavy flavor weak decays. In 1976 Maiani analyzed the CP violation in the six-quark theory and predicted the very small electric dipole moment of the neutron. In the 1980s he started using the numerical simulation of lattice QCD and this led to the first prediction of the decay constant of pseudoscalar charmed mesons and of B mesons.
A proponent of supersymmetry, Maiani once said that the search for it was "primary goal of modern particle physics".
He has not confined his interest to the theoretical side of physics either, with involvement in ALPI, EUROBALL, DAFNE, VIRGO and the LHC.
Honors and awards
1979 Matteucci Medal, Accademia Nazionale dei XL
1987 Sakurai Prize of the American Physical Society
1996 Doctor honoris causa, Université de la Méditerranée, Aix-Marseille
2007 Dirac Medal, Abdus Salam International Centre for Theoretical Physics, Trieste, Italy
2010 Doctor honoris causa, Benemérita Universidad Autónoma de Puebla, Puebla, México
2013 Bruno Pontecorvo Prize by the Joint Institute for Nuclear Research, Dubna, Russia
See also
GIM mechanism
External links
Scientific publications of Luciano Maiani on INSPIRE-HEP
References
1941 births
People associated with CERN
Living people
Sammarinese physicists
Particle physicists
Experimental physicists
Experimental particle physics
Academic staff of the Sapienza University of Rome
Foreign fellows of Pakistan Academy of Sciences
Theoretical physicists
Members of the European Academy of Sciences and Arts
Foreign members of the Russian Academy of Sciences
J. J. Sakurai Prize for Theoretical Particle Physics recipients
Recipients of the Matteucci Medal
National Research Council (Italy) people
Fellows of the American Physical Society | Luciano Maiani | [
"Physics"
] | 884 | [
"Particle physicists",
"Theoretical physics",
"Experimental physics",
"Particle physics",
"Experimental particle physics",
"Theoretical physicists",
"Experimental physicists"
] |
10,914,612 | https://en.wikipedia.org/wiki/Per%20Arne%20Rikvold | Per Arne Rikvold (born 4 October 1948 in Norway) is an academic physicist specializing in materials science, condensed-matter physics and computational science.
He took the cand.real. degree at the University of Oslo in 1976 and the PhD at Temple University in 1983. He is James G. Skofronick Professor of Physics at Florida State University, where is affiliated with the Center for Materials Research and Technology (MARTECH), the School of Computational Science, and the National High Magnetic Field Laboratory.
He is an elected fellow of the Norwegian Academy of Science and Letters and of the American Physical Society.
References
1948 births
Living people
Norwegian physicists
Norwegian materials scientists
Norwegian emigrants to the United States
University of Oslo alumni
Temple University alumni
Florida State University faculty
Members of the Norwegian Academy of Science and Letters
Fellows of the American Physical Society
Computational physicists | Per Arne Rikvold | [
"Physics"
] | 173 | [
"Computational physicists",
"Computational physics"
] |
10,914,688 | https://en.wikipedia.org/wiki/Demerara%20Distillers | Demerara Distillers Ltd. is a Guyanese distillery known for the El Dorado Rum brand.
It was at one time the world's second largest producer of rum.
Organization
Demerara Distillers Ltd. (DDL) is a publicly owned company headquartered in Georgetown. DLL owns Demerara Fire and General Insurance Company Inc., Solutions 2000, Demerara Contractors Limited, Topco, and other subsidiary companies include Distribution Services Limited and European Breitenstein Holdings BV. They were one of the first five companies to become certified by ISO 9001 international Standard System, enabling export quality goods.
Under government management, DDL became the world's second largest producer of rum. DDL was one of the first state-owned manufacturers to be semi-privatized under the Economic Recovery Program in 1988. 12 million new shares were issued, reducing government ownership to roughly 47%, although another attempt to issue shares in 1990 was blocked by the government.
In 2006, DDL obtained one-third of the shares of National Rums of Jamaica, which is a subsidiary of Jamaica's National Sugar Company Limited.
Yesu Persaud was chairman of DDL until 2013. Through his contributions to Guyanese industry, 1983 he was awarded the Cacique Crown of Honour.
Komal Samaroo became the new CEO in 2014. In 2021, Samaroo addressed the threat that the Venezuelan border issue has on "Guyana's supply chain for agriculture and other food products to the region, and even further afield".
In 2016, Bharrat Jagdeo claimed that billions of dollars were lost tax settlement between DDL and the Guyana Revenue Authority. In 2002, a dispute arose regarding a consumption tax of about GY$5.3 billion.
Production
DDL credits the flavours of their rums to the oak barrels used in the distilling process and Guyana's tropical climate. The aging process in Guyana is supplemented by the high humidity and steady temperature. Rums are blended from different vintages produced in different stills, then aged in oak barrels.
Promotion
Despite international familiarity, El Dorado and other rums have fallen behind other liquors, such as vodka, in successful marketing or an effective classification system.
DDL sponsors countless local events, such as chess tournaments, Guyana Fashion Week, Soca Monarch competitions, and Mashramani events. They were an official partner of the inaugural tournament of the 2013 Caribbean Premier League, sponsoring the tournament's Catch of the Match award, which went to one player in each of the 24 matches who makes a catch.
A 'rum route' was launched by the Guyana Tourism Authority (GTA) in collaboration with the Caribbean Tourism Organization. The tour includes visits to Uitvlugt Estate and Blairmont Estate and commercial ventures like rum shops, distilleries, and production, as well as the historical connection to slavery and indentured servants.
References
External links
Demerara Distillers - Official Site
Guide to Guyana's Demerara Rum
Rums
Guyanese brands
Food and drink in Guyana
Distilleries
Sugar industry of Guyana | Demerara Distillers | [
"Chemistry"
] | 641 | [
"Distilleries",
"Distillation"
] |
10,915,035 | https://en.wikipedia.org/wiki/Rifle%20bedding | Rifle bedding is a gunsmithing process of providing a rigid and consistent foundation for a rifle’s operational components, by creating a stable and close-fitting bearing surface between the gun's functional parts (i.e. the receiver housing the barrelled action) and its structural support (i.e. the stock) that do not deform with heat, pressure and moisture, or shift under the shear stress of the recoil from firing. The bedding process is often an aftermarket modification, and is done for the goal of accurizing the rifle and (to a lesser extent) prolonging the service life of the stock.
Purpose
Increasing accuracy
Bedding increases accuracy in part by relieving stress on the action. The rifle's action will rarely sit flush in the stock without bedding. This causes the action to flex when tightening the fixing screws that hold the action to the stock. If the stock is wooden, it will also expand or shrink significantly with environmental changes such as temperature and moisture, which causes changes in action screw tension. These result in inconsistencies during operation, which degrades accuracy. Bedding will create a flush bearing surface for the action and prevent flexing.
Bedding also reduces minute movements of the action within the stock. Without bedding, the action may be more likely to shift after each shot. If the action shifts and does not return to same spot in the stock the rifle will lose the ability to maintain zero.
The presence of the bedding material also adds a small amount of extra height to the action, and creates more of a gap between the barrel (which is fixed to the front of the action) and the fore-end of the stock, allowing the barrel to be better floated, which helps improve accuracy.
Prolonging stock life
Bedding can help prolong the life of the stock. Repeated shearing forces from recoils can create focal wear and chips in the stock surface, and eventually ruining the stock with repeated usage. Bedding redistributes stress over a larger area, reduces shifting between the action and the stock, and creates a hardier, protective epoxy coating over the softer stock contact surface, thus protecting it from mechanical wears over time.
Methods
Bedding involves molding an epoxy-based material onto the stock recess to fill away the gaps within its contact surface with the receiver (known as glass bedding), and/or inserting a metal cylinders (which act as compression members) around the action screws to reduce compressive shifting (known as pillar bedding). The receiver and the stock are sometimes fastened indirectly through an intermediate piece (usually made of rigid materials such as aluminium alloy) known as a bedding block, which multifunctionally serves as a larger pillar, a bedding surface and even recoil lugs. The contact interface on the stock may also be substituted by a metallic bedding frame known as a chassis, which is either embedded within the stock, or even completely replacing the stock like the lower receiver on many modern modular semi-automatic rifles.
Skim bedding refers to an adjustment of a glass bedding job, usually after wear and tear from use, which consists of removing a small layer of the bedding material — usually up to around — and adding new bedding material on top of that.
Several different bedding methods can be used depending on the type of stock, desired results and level of experience of the person attempting to perform the bedding. Methods include:
Full contact bedding of the action with the barrel floated.
Full contact bedding of the action and the barrel.
Full contact bedding of the action with a pressure-bearing pad for the barrel.
Pillar bedding of the action with the barrel floated.
Full length aluminum action bedding block.
Full contact bedding of the action with the barrel floated is a very common method for long range rifles with a heavy barrel. A free-floating barrel will generally produce the greatest accuracy. However, a pressure pad under the barrel just forward of the action can sometimes improve accuracy by acting on barrel harmonics and reducing stress on the action from the weight of the barrel. Pillar bedding can be used to float the action as well as the barrel, but the process is more difficult.
Precautions
If performed improperly, bedding can destroy a rifle. Mechanical locking occurs when bedding material is allowed to harden in holes or around protrusions on the action. If locking occurs, the action can be permanently fixed to the stock. Extreme measures may have to be taken to separate the stock from the action, possibly destroying one or both. Improperly applied or insufficient release agent can cause the bedding material to bind to the metal. If the trigger assembly is not removed prior to bedding, epoxy can seep into the trigger assembly and ruin it.
References
Further reading
Firearm components | Rifle bedding | [
"Technology"
] | 987 | [
"Firearm components",
"Components"
] |
10,915,042 | https://en.wikipedia.org/wiki/Hayabusa2 | is an asteroid sample-return mission operated by the Japanese state space agency JAXA. It is a successor to the Hayabusa mission, which returned asteroid samples for the first time in June 2010. Hayabusa2 was launched on 3 December 2014 and rendezvoused in space with near-Earth asteroid 162173 Ryugu on 27 June 2018. It surveyed the asteroid for a year and a half and took samples. It left the asteroid in November 2019 and returned the samples to Earth on 5 December 2020 UTC. Its mission has now been extended through at least 2031, when it will rendezvous with the small, rapidly-rotating asteroid .
Hayabusa2 carries multiple science payloads for remote sensing and sampling, and four small rovers to investigate the asteroid surface and analyze the environmental and geological context of the samples collected.
Mission overview
Asteroid 162173 Ryugu (formerly designated ) is a primitive carbonaceous near-Earth asteroid. Carbonaceous asteroids are thought to preserve the most pristine, untainted materials in the Solar System, a mixture of minerals, ice, and organic compounds that interact with each other. Studying it is expected to provide additional knowledge on the origin and evolution of the inner planets and, in particular, the origin of water and organic compounds on Earth, all relevant to the origin of life on Earth.
Initially, launch was planned for 30 November 2014, but was delayed to 3 December 2014 at 04:22:04 UTC (3 December 2014, 13:22:04 local time) on a H-IIA launch vehicle. Hayabusa2 launched together with PROCYON asteroid flyby space probe. PROCYON's mission was a failure. Hayabusa2 arrived at Ryugu on 27 June 2018, where it surveyed the asteroid for a year and a half and collected samples. It departed the asteroid in November 2019 and returned the samples to Earth in December 2020.
Compared to the previous Hayabusa mission, the spacecraft features improved ion engines, guidance and navigation technology, antennas, and attitude control systems. A kinetic penetrator (a high-explosive shaped charge) was shot into the asteroid surface to expose pristine sample material which was later collected for return to Earth.
Funding and history
Following the initial success of Hayabusa, JAXA began studying a potential successor mission in 2007. In July 2009, Makoto Yoshikawa of JAXA presented a proposal titled "Hayabusa Follow-on Asteroid Sample Return Missions". In August 2010, JAXA obtained approval from the Japanese government to begin development of Hayabusa2. The cost of the project estimated in 2010 was 16.4 billion yen (US$).
Hayabusa2 was launched on 3 December 2014, arrived at asteroid Ryugu on 27 June 2018, and remained stationary at a distance of about to study and map the asteroid. In the week of 16 July 2018, commands were sent to move to a lower hovering altitude.
On 21 September 2018, the Hayabusa2 spacecraft ejected the first two rovers, Rover-1A (HIBOU) and Rover-1B (OWL), from about a altitude that dropped independently to the surface of the asteroid. They functioned nominally and transmitted data. The MASCOT rover deployed successfully on 3 October 2018 and operated for about 16 hours as planned.
The first sample collection was scheduled to start in late October 2018, but the rovers encountered a landscape with large and small boulders but no surface soil for sampling. Therefore, it was decided to postpone the sample collection plans to 2019 and further evaluate various options for the landing. The first surface sample retrieval took place on 21 February 2019. On 5 April 2019, Hayabusa2 released an impactor to create an artificial crater on the asteroid surface. However, Hayabusa2 initially failed on 14 May 2019 to drop special reflective markers necessary onto the surface for guiding the descent and sampling processes, but later it successfully dropped one from an altitude of on 4 June 2019. The sub-surface sampling took place on 11 July 2019. The spacecraft departed the asteroid on 13 November 2019 (with departure command sent at 01:05 UTC on 13 November 2019). It successfully delivered the samples back to Earth on 6 December 2020 (JST), dropping the contents by parachute in a special container at a location in southern Australia. The samples were retrieved the same day for secure transport back to the JAXA labs in Japan.
Spacecraft
The design of Hayabusa2 is based on the first Hayabusa spacecraft, with some improvements. It has a mass of including fuel, and electric power is generated by two sets of solar arrays with an output of 2.6 kW at 1 AU, and 1.4 kW at 1.4 AU. The power is stored in eleven inline-mounted 13.2 Ah lithium-ion batteries.
Propulsion
The spacecraft features four solar-electric ion thrusters for propulsion called μ10, one of which is a backup. These engines use microwaves to convert xenon into plasma (ions), which are accelerated by a voltage applied by the solar panels and ejected out the back of the engine. The simultaneous operation of three engines generates thrusts of up to 28 mN. Although this thrust is very small, the engines are also extremely efficient; the of xenon reaction mass can change the speed of the spacecraft by up to 2 km/s.
The spacecraft has four redundant reaction wheels and a chemical reaction control system featuring twelve thrusters for attitude control (orientation) and orbital control at the asteroid. The chemical thrusters use hydrazine and MON-3, with a total mass of of chemical propellant.
Communication
The primary contractor NEC built the spacecraft, its Ka-band communications system and a mid-infrared camera. The spacecraft has two high-gain directional antennas for X-band and Ka-band. Bit rates are 8 bit/s to 32 kbit/s. The ground stations are the Usuda Deep Space Center, Uchinoura Space Center, NASA Deep Space Network and Malargüe Station (ESA).
Navigation
The optical navigation camera telescope (ONC-T) is a telescopic framing camera with seven colors to optically navigate the spacecraft. It works in synergy with the optical navigation camera wide-field (ONC-W2) and with two star trackers.
In order to descend to the asteroid surface to perform sampling, the spacecraft released one of five target markers in the selected landing zones as artificial guide marks, with highly reflective outer material that is recognized by a strobe light mounted on the spacecraft. The spacecraft also used its laser altimeter and ranging (LIDAR) as well as Ground Control Point Navigation (GCP-NAV) sensors during sampling.
Firsts
The Hayabusa2 spacecraft was the first to deploy operating rovers on an asteroid.
Science payload
The Hayabusa2 payload is equipped with multiple scientific instruments:
Remote sensing: Optical Navigation Camera (ONC-T, ONC-W1, ONC-W2), Near-Infrared Camera (NIR3), Thermal-Infrared Camera (TIR), Light Detection And Ranging (LIDAR)
Sampling: Sampling device (SMP), Small Carry-on Impactor (SCI), Deployable Camera (DCAM3)
Four rovers: Mobile Asteroid Surface Scout (MASCOT), Rover-1A, Rover-1B, Rover-2.
Remote sensing
The Optical Navigation Cameras (ONCs) were used for spacecraft navigation during the asteroid approach and proximity operations. They also remotely imaged the surface to search for interplanetary dust around the asteroid. ONC-T is a telephoto camera with a 6.35° × 6.35° field of view and several optical filters carried in a carousel. ONC-W1 and ONC-W2 are wide angle (65.24° × 65.24°) panchromatic (485–655 nm) cameras with nadir and oblique views, respectively.
The Near-Infrared Spectrometer (NIRS3) is a spectrograph operating at a wavelength of 1.8–3.2 μm. NIRS3 was used for analysis of surface mineral composition.
The Thermal-Infrared Imager (TIR) is a thermal infrared camera working at 8–12 μm, using a two-dimensional microbolometer array. Its spatial resolution is 20 m at 20 km distance or 5 cm at 50 m distance (70 ft at 12 mi, or 2 in at 160 ft). It was used to determine surface temperatures in the range .
The Light Detection And Ranging (LIDAR) instrument measured the distance from the spacecraft to the asteroid surface by measuring the reflected laser light. It operated over an altitude range between 30 m and 25 km (100 ft and 16 mi).
When the spacecraft was closer to the surface than during the sampling operation, the Laser Range Finders (LRF-S1, LRF-S3) were used to measure the distance and the attitude (orientation) of the spacecraft relative to the terrain. The LRF-S2 monitored the sampling horn to trigger the sampling projectile.
LIDAR and ONC data are being combined to determine the detailed topography (dimensions and shape) of the asteroid. Monitoring of a radio signal from Earth allowed measurement of the asteroid's gravitational field.
Rovers
Hayabusa2 carried four small rovers to explore the asteroid surface in situ, and provide context information for the returned samples. Due to the minimal gravity of the asteroid, all four rovers were designed to move around by short hops instead of using normal wheels. They were deployed at different dates from about altitude and fell freely to the surface under the asteroid's weak gravity. The first two rovers, called HIBOU (previously Rover-1A) and OWL (previously Rover-1B), landed on asteroid Ryugu on 21 September 2018. The third rover, called MASCOT, was deployed 3 October 2018. Its mission was successful. The fourth rover, known as Rover-2 or MINERVA-II-2, failed before release from the orbiter. It was released on 2 October 2019 to orbit the asteroid and perform gravitational measurements before being allowed to impact the asteroid a few days later.
MINERVA-II
MINERVA-II is a successor to the MINERVA lander carried by Hayabusa. It consists of two containers with 3 rovers.
MINERVA-II-1 is a container that deployed two rovers, Rover-1A (HIBOU) and Rover-1B (OWL), on 21 September 2018. It was developed by JAXA and the University of Aizu. The rovers are identical having a cylindrical shape, diameter and tall, and a mass of each. They move by hopping in the low gravitational field, using a torque generated by rotating masses within the rovers. Their scientific payload is a stereo camera, wide-angle camera, and thermometers. Solar cells and double-layer capacitors provide the electrical power. The MINERVA-II-1 rovers were successfully deployed 21 September 2018. Both rovers performed successfully on the asteroid surface, sending images and video from the surface. Rover-1A operated for 113 asteroid days (36 Earth days) returning 609 images from the surface, and Rover-1B operated for 10 asteroid days (3 Earth days) returning 39 images from the surface.
The MINERVA-II-2 container held the ROVER-2 (sometimes referred to as MINERVA-II-2), developed by a consortium of universities led by Tohoku University in Japan. This was an octagonal prism shape, diameter and tall, with a mass of about . It had two cameras, a thermometer and an accelerometer. It was equipped with optical and ultraviolet LEDs to illuminate and detect floating dust particles. ROVER-2 carried four mechanisms to move around using short hops. Rover-2 had problems prior to deployment from the orbiter but was released on 2 October 2019 to orbit the asteroid and perform gravitational measurements. It was then crashed onto the asteroid surface a few days later on 8 October 2019.
MASCOT
The Mobile Asteroid Surface Scout (MASCOT) was developed by the German Aerospace Center (DLR) in cooperation with the French space agency CNES. It measures and has a mass of . MASCOT carries four instruments: an infrared spectrometer (MicrOmega), a magnetometer (MASMAG), a radiometer (MARA), and a camera (MASCAM) that imaged the small-scale structure, distribution and texture of the regolith. The rover is capable of tumbling once to reposition itself for further measurements. It collected data on the surface structure and mineralogical composition, the thermal behaviour and the magnetic properties of the asteroid. It has a non-rechargeable battery that allowed for operations for approximately 16 hours. The infrared radiometer on the InSight Mars lander, launched in 2018, is based on the MASCOT radiometer.
MASCOT was deployed 3 October 2018. It had a successful landing and performed its surface mission successfully. Two papers were published describing the results from MASCOT in the scientific journals Nature Astronomy and Science. One finding of the research was that C-type asteroids consist of more porous material than previously thought, explaining a deficit of this meteorite type. Meteorites of this type are too porous to survive the entry into the atmosphere of planet Earth. Another finding was that Ryugu consists of two different almost black types of rock with little internal cohesion, but no dust was detected. A third paper describing results from MASCOT was published in the Journal of Geophysical Research and describes the magnetic properties of Ryugu, showing that Ryugu does not have a magnetic field on a boulder scale.
Objects deployed by Hayabusa2
Sampling
The original plan was for the spacecraft to collect up to three samples:
1) surface material that exhibits traits of hydrous minerals;
2) surface material with either unobservable or weak evidence of aqueous alterations;
3) excavated sub-surface material.
The first two surface samples were scheduled to start in late October 2018, but the rovers showed large and small boulders and insufficient surface area to sample, so the mission team decided to postpone sampling to 2019 and evaluate various options. The first surface sampling was completed on 22 February 2019 and obtained a substantial amount of topsoil, so the second surface sampling was postponed and was eventually cancelled to decrease the risks to the mission.
The second and final sample was collected from material that was dislodged from beneath the surface by the kinetic impactor (SCI impactor) shot from a distance of . All samples are stored in separate sealed containers inside the sample return capsule (SRC).
Surface sample
Hayabusa2 sampling device is based on Hayabusa. The first surface sample retrieval was conducted on 21 February 2019, which began with the spacecraft's descent, approaching the surface of the asteroid. When the sampler horn attached to Hayabusa2 underside touched the surface, a tantalum projectile (bullet) was fired at into the surface. The resulting ejected materials were collected by a "catcher" at the top of the horn, which the ejecta reached under their own momentum under microgravity conditions.
Sub-surface sample
The sub-surface sample collection required an impactor to create a crater in order to retrieve material under the surface, not subjected to space weathering. This required removing a large volume of surface material with a powerful impactor. For this purpose, Hayabusa2 deployed on 5 April 2019 a free-flying gun with one "bullet", called the Small Carry-on Impactor (SCI); the system contained a copper projectile, shot onto the surface with an explosive propellant charge. Following SCI deployment, Hayabusa2 also left behind a deployable camera (DCAM3) to observe and map the precise location of the SCI impact, while the orbiter maneuvered to the far side of the asteroid to avoid being hit by debris from the impact.
It was expected that the SCI deployment would induce seismic shaking of the asteroid, a process considered important in the resurfacing of small airless bodies. However, post-impact images from the spacecraft revealed that little shaking had occurred, indicating the asteroid was significantly less cohesive than was expected.
Approximately 40 minutes after separation, when the spacecraft was at a safe distance, the impactor was fired into the asteroid surface by detonating a shaped charge of plasticized HMX for acceleration. The copper impactor was shot onto the surface from an altitude of about and it excavated a crater of about in diameter, exposing pristine material. The next step was the deployment on 4 June 2019 of a reflective target marker in the area near the crater to assist with navigation and descent. The touchdown and sampling took place on 11 July 2019.
Sample return
The spacecraft collected and stored the samples in separate sealed containers inside the sample-return capsule (SRC), which is equipped with thermal insulation. The container is external diameter, in height, and a mass of about .
At the end of the science phase in November 2019, Hayabusa2 used its ion engines to change orbit and return to Earth. Hours before Hayabusa2 flew past Earth in late 2020, it released the capsule, on 5 December 2020 at 05:30 UTC. The capsule was released spinning at one revolution per three seconds. The capsule re-entered the Earth's atmosphere at , and it deployed a radar-reflective parachute at an altitude of about , and ejected its heat shield while transmitting a position beacon signal. The sample capsule landed at the Woomera Test Range in Australia. The total flight distance was .
Any volatile substances will be collected before the sealed containers are opened. The samples will be curated and analyzed at JAXA's Extraterrestrial Sample Curation Center, where international scientists can request a small portion of the samples. The spacecraft brought back a capsule containing carbon-rich asteroid fragments that scientists believe could provide clues about the ancient delivery of water and organic molecules to Earth.
JAXA is sharing a portion of these samples with NASA. In exchange, NASA will provide JAXA a percentage of a sample of asteroid Bennu, when the agency's OSIRIS-REx spacecraft returned to Earth from the space rock on 24 September 2023.
A November 2024 study published in Meteoritics & Planetary Science examined a sample returned from the asteroid Ryugu by the Hayabusa2 mission. Despite stringent contamination control measures, terrestrial microorganisms rapidly colonized the sample. Researchers concluded that the observed microbial growth originated from Earthly contamination during sample preparation rather than being indigenous to the asteroid. This finding underscores the difficulty of preventing microbial contamination, even in highly controlled laboratory environments.
Mission extension (Hayabusa2♯)
With the successful return and retrieval of the sample capsule on 6 December 2020 (JST), Hayabusa2 will now use its remaining of xenon propellant (from the initial ) to extend its service life and fly out to explore new targets. As of September 2020, a fly-by of 98943 Torifune in July 2026 and a rendezvous with in July 2031 were selected for the mission extension. The observation of Torifune will be a high-speed fly-by of an S-type asteroid. The fixed camera of Hayabusa2 was not designed for this type of fly-by. The rendezvous with will be the first visit of a fast rotating micro-asteroid, with a rotation period of about 10 minutes. Between 2021 and 2026, the spacecraft will also conduct transit observations of exoplanets. An option to conduct a Venus flyby to set up an encounter with was also studied.
Selected EAEEA (Earth → Asteroid → Earth → Earth → Asteroid) scenario:
December 2020: Extension mission start
2021 until July 2026: cruise operation
July 2026: S-type asteroid 98943 Torifune high-speed fly-by
December 2027: Earth swing-by
June 2028: Second Earth swing-by
July 2031: Target body () rendezvous
The nickname of the Extended Mission is “Hayabusa2♯” (read “Hayabusa2 Sharp”). The character “♯” is a musical symbol that means “raise the note by a semitone”, and for this mission, it is also the acronym for “Small Hazardous Asteroid Reconnaissance Probe”. This name indicates that the Hayabusa2 Extended Mission is set to investigate small but potentially dangerous asteroids that may collide with the Earth in the future. The English meaning of the word “sharp” also highlights the extremely challenging nature of this mission, which is also reflected in the musical meaning of “raise the note by a semitone”, suggestive of raising of the rank of the mission.
As the character “♯” is a musical symbol, it can be difficult to enter in practice when typing. The symbol can therefore be substituted with the “#” symbol (number sign / pound / hash) that is on computer keyboards or phones. There is no problem with the notation “Hayabusa2♯” (musical symbol) or “Hayabusa2#”.
See also
Abiogenesis
OSIRIS-REx – NASA asteroid sample return mission to 101955 Bennu (operational at the same time as Hayabusa2)
Panspermia
Japanese minor body probes
Suisei spacecraft
Notes
References
External links
Hayabusa2 project website
JAXA Hayabusa2 website
Hayabusa2 Science Data Archives hosted by the DARTS archive (ISAS)
MASCOT related publications by the Institute of Planetary Research hosted by Europlanet
Hayabusa2 images scientific commentary , University of Tokyo
Asteroid Explorer Hayabusa2, NEC
Hayabusa2 3D model, Asahi Shinbun
2014 in Japan
Japanese space probes
Missions to near-Earth asteroids
Sample return missions
Astrobiology space missions
Exoplanet search projects
Space probes launched in 2014
Spacecraft launched by H-II rockets
Articles containing video clips | Hayabusa2 | [
"Astronomy"
] | 4,447 | [
"Astronomy projects",
"Exoplanet search projects"
] |
10,915,325 | https://en.wikipedia.org/wiki/First%20Solar | First Solar, Inc. is a publicly traded American manufacturer of solar panels, and provider of utility-scale PV power plants, supporting services that include finance, construction, maintenance and end-of-life panel recycling. First Solar uses rigid thin-film modules for its solar panels, and produces CdTe panels using cadmium telluride (CdTe) as a semiconductor.
The company was founded in 1990 by inventor Harold McMaster as Solar Cells, Inc. and the Florida Corporation in 1993 with JD Polk. In 1999 it was purchased by True North Partners, LLC, who rebranded it as First Solar, Inc.
The company went public in 2006, trading on the NASDAQ. Its current chief executive is Mark Widmar, who succeeded the previous CEO James Hughes July 1, 2016. First Solar is based in Tempe, Arizona.
In 2009, First Solar became the first solar panel manufacturing company to lower its manufacturing cost to $1 per watt. As of 2022, First Solar was considered the fourth-largest solar company on American stock exchanges by 12-month trailing revenue and in 2012 was ranked sixth in Fast Companys list of the world's 50 most innovative companies.
In 2011, it ranked first on Forbes's list of America's 25 fastest-growing technology companies. It is listed on the Photovoltaik Global 30 Index since the beginning of this stock index in 2009. The company was also listed as No. 1 in Solar Power World magazine's 2012 and 2013 rankings of solar contractors.
Technology
First Solar manufactures cadmium telluride (CdTe)-based photovoltaic (PV) modules, which produce electricity with a thin CdTe film on glass.
In 2013, the company produced CdTe-panels with an efficiency of about 14 percent at a reported cost of 59 cents per watt. In August 2019, researchers from NREL and First Solar published a Nature Energy article demonstrating a way to achieve 20.8% solar cell efficiency.
History
In 1984, inventor and entrepreneur Harold McMaster founded Glasstech Solar. After trying amorphous silicon, he shifted to CdTe and founded Solar Cells, Inc. (SCI) in 1990. In February 1999, SCI was acquired by True North Partners, which then formed First Solar, LLC'.
At the end of 2009, First Solar had surpassed an energy power production rate of 1 GW and was the largest producer of PV cells in the world.
The company is headquartered in Tempe, Arizona and has manufacturing facilities in Perrysburg, Ohio, Kulim, Malaysia, Ho Chi Minh City, Vietnam and Chennai, India.
In July 2010, First Solar formed a utility systems business group to address the large-scale PV systems solutions market. Utility systems are now the company's core business focus, with a strategy to focus on markets that do not require subsidies to support the solar generation business.
On April 17, 2012, First Solar announced it would restructure operations worldwide. This restructuring process included phasing out operations in Frankfurt (Oder), Germany and idling four production lines in Kulim, Malaysia. 30% of First Solar's workforce was laid off as a result of these actions, which were blamed on market volatility and reduced demand. Mark Widmar, the CFO of First Solar, said, "We need to resize our business to a level of demand that is highly reliable and predictable."
On July 1, 2016, Mark Widmar was appointed CEO of First Solar. Previously he had been chief financial officer. Company founder and former CEO Mike Ahearn remains chairman of the board.
In May 2023, First Solar acquired Evolar, a European company that provided perovskite technology. The deal was valued at $38M USD.
Market history
Historically, First Solar sold its products to solar project developers, system integrators, and independent power producers. Early sales were primarily in Germany because of strong incentives for solar enacted in the German Renewable Energy Sources Act (EEG) of 2000 (cp. Solar power in Germany). Declines and uncertainty in feed-in-tariff subsidies for solar power in European markets, including Germany, France, Italy and Spain, prompted major PV manufacturers, such as First Solar, to accelerate their expansion into other markets, including the U.S., India and China.
Beginning in December 2011, First Solar shifted away from existing markets that are heavily dependent on government subsidies and toward providing utility-scale PV systems in sustainable markets with immediate need. As a result, it now competes against conventional power generators, and has reduced its focus on the rooftop market.
On February 24, 2009, First Solar's cost per watt broke the $1 barrier, reaching $0.98. Production cost has continued to fall and in February 2013, reached $0.68 per watt.
11.4 GW of solar modules were sold in 2023. Production costs of 18.8 Cent/Watt were forecast in February 2024, with average sales prices of 18.2 Cent/kWh for sales of around 16 GW in 2024.
Production history
In 2019, the company was expected to pass annual shipments of panels for 5,400 MWp. Production started in Perrysburg, Ohio, expanded in 2010. Between 2007 and 2012, production grew in additional plants in Frankfurt (Oder) in Germany, in Kulim Hi-Tech Park in Malaysia and in France. Other locations considered for expansions before 2012 were Vietnam and Mesa, AZ. The 2023 Sustainability Report published in August 2023 highlights findings related to Environmental, Social, and Governance (ESG) metrics, including modern slavery and forced labor findings. Report findings shared with media support the company's proactive efforts and due diligence to address human right violations within the solar power supply chain as they are discovered. First Solar's products have been released by U.S. Customs and Border Protection and comply with the Uyghur Forced Labor Prevention Act.
Market performance
While First Solar witnessed record sales of over $3.37 billion in 2012, its restructuring efforts impacted the bottom line, leading to a net loss of $96.3 million – or $1.11 per share – for the year.
Historically, the low cost of First Solar's modules has been the key to its market performance. The use of cadmium telluride instead of silicon allowed it to achieve a significantly lower module cost ($0.67 per watt), compared to crystalline-silicon PV, which averaged $1.85 per watt in 2010.
As the company shifts its focus away from module sales to utility-scale projects, it will need to become price competitive with non-solar power sources, a move which its executives say will require the company to reduce manufacturing costs and optimize efficiency.
Installations
First Solar had installed 1,505 MW of solar capacity as of 2012. As of 2019, First Solar has over 17GW deployed globally. Below are some of First Solar's solar installations and development projects:
North America
802 MW Copper Mountain Solar Facility near Boulder City, NV, constructed in 5 phases for Sempra Energy and Consolidated Edison.
550 MW Topaz Solar Farm in San Luis Obispo County, CA, acquired by MidAmerican Energy Holdings.
550 MW Desert Sunlight Solar Farm in Riverside County, CA, acquired by NextEra Energy and GE Energy Financial Services.
290 MW Agua Caliente Solar Project in Yuma County, AZ, constructed for NRG Energy and MidAmerican Renewables.
230 MW Antelope Valley Solar Ranch in Los Angeles, CA, completed 2014 and acquired by Exelon Corp.
80 MW Sarnia Solar Farm in Ontario, Canada, completed, owned by Enbridge.
50 MW Silver State North Solar Project, in Boulder County, NV, completed, acquired by Enbridge.
Europe, Middle East, and North Africa
Mohammed bin Rashid Al Maktoum Solar Park in Saih Al-Dahal, UAE, includes a 13 MWDC solar power plant built by First Solar for the Dubai Electricity & Water Authority (DEWA).
Stadtwerke Trier (SWT) in Trier, Germany, is one of the world's largest thin-film solar plants. As of February 2009, it was estimated the facility would produce over 9 GWh per year, which would supply power to more than 2,400 homes each year. Additionally, it is estimated the facility will conserve 100,000 tons of over 20 years.
The Ramat Hovav solar field is the largest PV power plant built so far in Israel's solar power sector. Constructed by Belectric over a previous evaporation pond, it has a nominal capacity of 37.5 MW. The facility became fully operational in December 2014.
Waldpolenz Solar Park near Leipzig, Germany, was built and developed by Juwi Group, and has a capacity of 40 MW. The facility became fully operational in 2008.
In December 2009, the Lieberose Photovoltaic Park, Germany's biggest conversion land project (126 hectares) on a former military training area, was opened with an output of 53 MW. The solar park uses 700,000 solar modules.
For the Sports Stadium Bentegodi in Verona, Italy, First Solar supplied more than 13,000 thin film modules for a rooftop installation.
Asia and Australia
10 MW Greenough River Solar Farm in Western Australia, completed for Verve Energy and GE Energy Financial Services.
159 MW AGL Energy projects, to be constructed in Nyngan and Broken Hill, New South Wales. The 53 MW Broken Hill project was completed in 2015.
See also
Thin film solar cell
Cadmium telluride photovoltaics
Copper indium gallium selenide (CIGS)
Photovoltaic power stations
SolarCity
Solar power in Germany
5N Plus Inc.
References
External links
Manufacturing companies based in Phoenix, Arizona
Solar energy companies of the United States
Photovoltaics manufacturers
Thin-film cell manufacturers
Manufacturing companies established in 1999
Companies listed on the Nasdaq
1999 establishments in Arizona
2006 initial public offerings
Walton family
American companies established in 1999
American brands | First Solar | [
"Engineering"
] | 2,052 | [
"Photovoltaics manufacturers",
"Engineering companies"
] |
10,915,559 | https://en.wikipedia.org/wiki/Airspan%20Networks | Airspan Networks is an American telecommunications company, headquartered in Boca Raton, Florida. The company develops Radio Access Network technology including the Sprint 'Magic Box' and cells (both small and macro) for the Rakuten virtualized network.
Airspan was originally a product division of DSC Communications, a manufacturer of telephone switching equipment. Original products included a CDMA-based radio platform used for the fixed wireless market. In 1998, the company separated from DSC Communications and announced Eric Stonestrom as CEO and President.
Airspan originally focused its product line on the small cell and mini-macro equipment market, used by mobile operators to extend wireless services. Through the acquisition of Mimosa Networks in 2018, the company entered the market for fixed wireless solutions which are used in commercial, enterprise and operator networks for wireless backhaul and access applications.
Airspan's 5G NR development program is focused on mmWave, Sub 6 GHz, Massive MIMO, and Open Virtual RAN architectures. The company also offers fixed wireless access and backhaul solutions for PTP (point-to-point) and PTMP (point-to-multi-point) applications through its Mimosa Products.
In March, 2019, Airspan announced a partnership with Google in support of CBRS services.
In August 2021, Airspan completed a business combination with New Beginnings Acquisition Corp. The newly-renamed "Airspan Networks Holdings Inc. then began trading on the NYSE American under the ticker symbol MIMO.
History
The company was founded in January 1998.
In May 1998, Eric D. Stonestrom was named president and chief executive officer of the company.
Its first product, AS4020 platform, was based on CDMA radio technology adapted for fixed wireless access points.
In July 2000, as the dot-com bubble was bursting, the company became a public company and raised $82.5 million in an initial public offering. Its stock price rose 113% in its first day of trading.
In 2004, the company made an agreement with Neda Telecommunications, a subsidiary of Aspen Wind Corporation, to send radios to Kabul, Afghanistan.
In the fourth quarter of 2005, the company released its WiMAX product line.
In September 2006, Oak Investment Partners made a $29 million investment in the company.
In 2010, the company teamed with LightSquared to market LightSquared's 1.4 GHz wireless spectrum in the United States. The spectrum is targeted primarily at the utility industry for Smart Grid deployments.
In 2009, the company's stock was delisted from the NASDAQ.
In March 2021, the company announced that it would be re-listed on NYSE American through a reverse merger with New Beginnings Acquisition Corporation, a special-purpose acquisition company.
In August 2021, the company completed the reverse merger with New Beginnings Acquisition Corporation. The parent company was hence renamed "Airspan Networks Holdings Inc." and began trading on the NYSE American under the ticker symbol MIMO.
In May 2023, Glenn Laxdal was announced as the new CEO.
In 2023 Airspan sold Mimosa to Indian communication giant JIO for $60 million through JIO wholly owned subsidiary Radisys Corporation.
In March 2024, the company announced that it would become private after receiving up to $95 million in new equity financing. The company's stock was soon delisted from the NYSE, and the company filed for a voluntary prepackaged Chapter 11 bankruptcy filing in order to implement the deal.
Awards and recognition
Airspan's industry recognition and awards date back to 2007 when the company won the 'Best of WiMAX World USA Award'.
Airspan & Jio won the SCF 2020 Award for Excellence in Commercial Deployment (Urban).
Sprint and Airspan won the SCF 2019 Small Cell Award for Excellence in Commercial Deployment.
Sprint & Airspan Netlworks – Sprint LTE Magic Box won the SCF Award 2018 Excellence in Commercial Deployment (Residential).
Airspan and Sprint were selected as the winners for the “Best Mobile Technology Breakthrough” at GLOMO 2018 Awards.
Airspan and Qualcomm won the SCF 2021 Small Cell Award for Excellence in Commercial Deployment for 5G OpenRANGE mmWave outdoor small deployment.
References
External links
1998 establishments in Florida
2000 initial public offerings
Companies formerly listed on the New York Stock Exchange
Companies that filed for Chapter 11 bankruptcy in 2024
American companies established in 1998
Companies based in Boca Raton, Florida
Technology companies established in 1998
Telecommunications companies of the United States | Airspan Networks | [
"Technology"
] | 917 | [
"Computer hardware companies",
"Computers"
] |
10,916,488 | https://en.wikipedia.org/wiki/Philip%20Froelich | Dr. Philip 'Flip' Nissen Froelich, Jr. is an American academic oceanographic scientist, whose research uses biogeochemistry dynamics to address human impacts on the world's oceans.
Early life and career
Froelich graduated from Duke University in 1968. He obtained a Ph.D. from the University of Rhode Island in 1979.
He is a Francis Eppes Professor of Oceanography at Florida State University, where he is involved in the interdisciplinary Biogeochemical Dynamics Program. He is also affiliated with the National High Magnetic Field Laboratory.
References
External links
Florida State University faculty profile
Duke University alumni
Florida State University faculty
American oceanographers
Living people
Biogeochemists
Year of birth missing (living people)
University of Rhode Island alumni | Philip Froelich | [
"Chemistry"
] | 155 | [
"Geochemists",
"Biogeochemistry",
"Biogeochemists"
] |
10,916,602 | https://en.wikipedia.org/wiki/Christopher%20Llewellyn%20Smith | Sir Christopher Hubert Llewellyn Smith (born 19 November 1942) is an Emeritus Professor of Physics at the University of Oxford.
Education
Llewellyn Smith was educated at the University of Oxford (BA) and completed his Doctor of Philosophy degree in theoretical physics at New College, Oxford in 1967.
Career and research
After his DPhil he worked at the Lebedev Physical Institute in Moscow, CERN and then the SLAC National Accelerator Laboratory before returning to Oxford in 1974. Llewellyn Smith was elected a Fellow of the Royal Society in 1984.
While Chairman of Oxford Physics (1987–92), he led the merger of five different departments into a single Physics Department. Llewellyn Smith was Director General of CERN from 1994 to 1998. Thereafter he served as Provost and President of University College London (1999–2002).
Awards and honours
Llewellyn Smith received the James Clerk Maxwell Medal and Prize in 1979, and Glazebrook Medal and Prize of the Institute of Physics in 1999 and was knighted in 2001. In 2004, he became Chairman of the Consultative Committee for Euratom on Fusion (CCE-FU). Until 2009 he was Director of UKAEA Culham Division, which holds the responsibility for the United Kingdom's fusion programme and operation of the Joint European Torus (JET). He is a member of the Advisory Council for the Campaign for Science and Engineering.
In 2013, he joined the National Institute of Science Education and Research (NISER), Bhubaneswar, India as a Distinguished Professor.
In 2015, he was awarded the Royal Medal of the Royal Society.
Personal life
Llewellyn Smith married in 1966 and has one son and one daughter.
References
1942 births
Living people
Alumni of New College, Oxford
British nuclear physicists
English physicists
People associated with CERN
Experimental particle physics
Experimental physicists
Academics of University College London
Fellows of New College, Oxford
Fellows of St John's College, Oxford
Fellows of the Royal Society
Foreign fellows of the Indian National Science Academy
International Centre for Synchrotron-Light for Experimental Science Applications in the Middle East people
Knights Bachelor
Maxwell Medal and Prize recipients
Particle physicists
Provosts of University College London
Department of Physics, University of Oxford | Christopher Llewellyn Smith | [
"Physics"
] | 452 | [
"Experimental physics",
"Particle physics",
"Experimental particle physics"
] |
10,916,658 | https://en.wikipedia.org/wiki/Linear%20transformer%20driver | A linear transformer driver (LTD) within physics and energy, is an annular parallel connection of switches and capacitors. The driver is designed to deliver rapid high power pulses. The LTD was invented at the Institute of High Current Electronics (IHCE) in Tomsk, Russia. The LTD is capable of producing high current pulses, up to 1 mega amps (106 ampere), with a risetime of less than 100 ns. This is an improvement over Marx generator based pulsed power devices which require pulse compression to achieve such fast risetimes. It is being considered as a driver for z-pinch based inertial confinement fusion.
LTDs at Sandia National Laboratories
Sandia National Laboratory is currently investigating a z-pinch as a possible ignition source for inertial confinement fusion. On its "Z machine", Sandia can achieve dense, high temperature plasmas by firing fast, 100-nanosecond current pulses exceeding 20 million amps through hundreds of tungsten wires with diameters on the order of tens of micrometres. The LTD is currently being investigated as a driver for the next generation of high power accelerators.
Sandia's roadmap includes another future Z machine version called ZN (Z Neutron) to test higher yields in fusion power and automation systems. ZN is planned to give between 20 and 30 MJ of hydrogen fusion power with a shot per hour thanks to LTDs replacing the current Marx generators. After 8 to 10 years of operation, ZN would become a transmutation pilot plant capable of a fusion shot every 100 seconds.
The next step planned would be the Z-IFE (Z-inertial fusion energy) test facility, the first true z-pinch driven prototype fusion power plant. It is suggested it would integrate Sandia's latest designs using LTDs. Sandia labs recently proposed a conceptual 1 petawatt (1015 watts) LTD Z-pinch power plant, where the electric discharge would reach 70 million amperes.
See also
References
External links
Development and tests of fast 1-MA linear transformer driver stages
http://www.sandia.gov/news/resources/releases/2007/rapid-fire-pulse.html
http://www-ners.engin.umich.edu/labs/plasma/Research/ZPinch.html
Power (physics) | Linear transformer driver | [
"Physics",
"Mathematics"
] | 487 | [
"Force",
"Physical quantities",
"Quantity",
"Power (physics)",
"Energy (physics)",
"Wikipedia categories named after physical quantities"
] |
10,917,170 | https://en.wikipedia.org/wiki/Isotropic%20quadratic%20form | In mathematics, a quadratic form over a field F is said to be isotropic if there is a non-zero vector on which the form evaluates to zero. Otherwise it is a definite quadratic form. More explicitly, if q is a quadratic form on a vector space V over F, then a non-zero vector v in V is said to be isotropic if . A quadratic form is isotropic if and only if there exists a non-zero isotropic vector (or null vector) for that quadratic form.
Suppose that is quadratic space and W is a subspace of V. Then W is called an isotropic subspace of V if some vector in it is isotropic, a totally isotropic subspace if all vectors in it are isotropic, and a definite subspace if it does not contain any (non-zero) isotropic vectors. The of a quadratic space is the maximum of the dimensions of the totally isotropic subspaces.
More generally, if the quadratic form is non-degenerate and has the signature , then its isotropy index is the minimum of a and b. An important example of an isotropic form over the reals occurs in pseudo-Euclidean space.
Hyperbolic plane
Let F be a field of characteristic not 2 and . If we consider the general element of V, then the quadratic forms and are equivalent since there is a linear transformation on V that makes q look like r, and vice versa. Evidently, and are isotropic. This example is called the hyperbolic plane in the theory of quadratic forms. A common instance has F = real numbers in which case and are hyperbolas. In particular, is the unit hyperbola. The notation has been used by Milnor and Husemoller for the hyperbolic plane as the signs of the terms of the bivariate polynomial r are exhibited.
The affine hyperbolic plane was described by Emil Artin as a quadratic space with basis satisfying , where the products represent the quadratic form.
Through the polarization identity the quadratic form is related to a symmetric bilinear form .
Two vectors u and v are orthogonal when . In the case of the hyperbolic plane, such u and v are hyperbolic-orthogonal.
Split quadratic space
A space with quadratic form is split (or metabolic) if there is a subspace which is equal to its own orthogonal complement; equivalently, the index of isotropy is equal to half the dimension. The hyperbolic plane is an example, and over a field of characteristic not equal to 2, every split space is a direct sum of hyperbolic planes.
Relation with classification of quadratic forms
From the point of view of classification of quadratic forms, spaces with definite quadratic forms are the basic building blocks for quadratic spaces of arbitrary dimensions. For a general field F, classification of definite quadratic forms is a nontrivial problem. By contrast, the isotropic forms are usually much easier to handle. By Witt's decomposition theorem, every inner product space over a field is an orthogonal direct sum of a split space and a space with definite quadratic form.
Field theory
If F is an algebraically closed field, for example, the field of complex numbers, and is a quadratic space of dimension at least two, then it is isotropic.
If F is a finite field and is a quadratic space of dimension at least three, then it is isotropic (this is a consequence of the Chevalley–Warning theorem).
If F is the field Qp of p-adic numbers and is a quadratic space of dimension at least five, then it is isotropic.
See also
Isotropic line
Polar space
Witt group
Witt ring (forms)
Universal quadratic form
References
Pete L. Clark, Quadratic forms chapter I: Witts theory from University of Miami in Coral Gables, Florida.
Tsit Yuen Lam (1973) Algebraic Theory of Quadratic Forms, §1.3 Hyperbolic plane and hyperbolic spaces, W. A. Benjamin.
Tsit Yuen Lam (2005) Introduction to Quadratic Forms over Fields, American Mathematical Society .
Quadratic forms
Bilinear forms | Isotropic quadratic form | [
"Mathematics"
] | 875 | [
"Quadratic forms",
"Number theory"
] |
10,917,183 | https://en.wikipedia.org/wiki/Herwig%20Schopper | Herwig Franz Schopper (born 28 February 1924) is a German experimental physicist. He was the director general of CERN from 1981 to 1988.
Biography
Schopper was born in Lanškroun, Czechoslovakia, to a family of Austrian descent. He obtained his diploma and doctorate from the University of Hamburg, studying under Wilhelm Lenz and Rudolf Fleischmann. In 1950–51 he was a research assistant with Lise Meitner at Stockholm and in 1956–57 at the Cavendish Laboratory under Otto Robert Frisch.
During these fellowships, Schopper worked on nuclear physics and contributed substantially to the evidence of parity violation in weak interactions. He measured the circular polarization of gamma rays following a beta decay, thought unfeasible by Lee and Yang, and showed in the same experiment that the helicities of neutrino and antineutrino are opposite. Later, he was involved in an experiment to test time reversal symmetry. In 1956, he followed Fleischmann to the University of Erlangen where he continued to do research in optics and solid-state physics, with emphasis on thin metal layers, which he had started at Hamburg. Also he developed, along with Clausnitzer, the first source of polarised protons. In 1957 he became Privatdozent at the University of Erlangen.
From 1958 to 1961, Schopper was an associate professor at the University of Mainz where he established the Institute for Experimental Nuclear Physics. In 1960–61 he worked under Robert R. Wilson at Cornell University to be introduced to elementary particle physics, namely the use of electron scattering to study the structure of the proton and neutron.
Schopper was appointed professor at the University of Karlsruhe in 1961 and director of the newly established Institutes for Experimental Nuclear Physics of TH Karlsruhe and the Karlsruhe Nuclear Research Centre. In order to continue his research on electron scattering he set up a group to carry out one of the first experiments at DESY. He also created a group at CERN to investigate neutron scattering at high energies at the Proton Synchrotron (PS) and Intersecting Storage Rings (ISR). These experiments where then continued at the Institute for High Energy Physics (IHEP) in Serpukhov, Russia. The group made important contributions to the study of neutron-proton and neutron-nuclei scattering cross sections. For this purpose, the first hadron calorimeter was developed and optimised by Monte Carlo simulations. Another group at Karlsruhe developed the first superconducting high frequency cavities in Europe, a technology which was transferred to CERN for particle separators and later for particle acceleration at LEP.
At CERN, he was a research associate in 1966–67, became division leader of the Nuclear Physics Division in 1970, member of the directorate responsible for the co-ordination of the experimental programme until 1973 and chairman of the ISR Committee from 1973 to 1976.
In 1973 Schopper became professor at the University of Hamburg and the chairman of the directorate of DESY, serving until end of 1980. He was responsible for the installation of the ARGUS detector at DORIS which later resulted in the first evidence of B – B bar mixing. Also, by establishing HASYLAB at DORIS synchrotron light science became an important branch of research at DESY.
He proposed and completed the construction of the electron-positron collider PETRA which led to the discovery and study of the gluon. During his mandate, DESY, a national laboratory became as far as science was concerned an international particle physics laboratory. This included the start of the first collaboration with China.
From 1977 to 1979, Schopper was chairman of the Association of the German Large Research Centres (now Helmholtz Association) and member of various advisory bodies of the Federal Ministry of Research, the Deutsche Forschungs Gemeinschaft and the Max Planck Society.
After being member of the Scientific Policy Committee at CERN, Schopper was elected director general and served from 1981 to 1988. His first task was to unite the two CERN laboratories existing at that time under two Directors General. The Large Electron–Positron Collider (LEP) was also proposed and constructed under his leadership. This facility allowed the verification of the standard model of particle physics, namely that it is a renormalizable field theory, leading to the award of the Nobel Prize to the theoreticians Veltman and t'Hooft. Furthermore, it enabled the precise determination of fundamental parameters of the electroweak force, such as the
W± and Z masses, and proved the existence of three neutrino families. Thus, this particle accelerator transformed high energy physics into a field of precision measurements and provided estimates to the mass of the top quark, Higgs boson and other supersymmetric and hypothetical particles.
LEP was approved under the condition of a reduced and constant budget with the consequence that some unique activities at CERN (e.g. ISR) had to be abandoned. Schopper was obliged to introduce a new way of international collaboration for the four LEP experiments since CERN could not provide funds for them. The experiments became rather independent activities organised in a rather democratic way bringing together hundreds of scientists from many universities and national organisations. The LEP experiments became a model for the later LHC experiments, shaping the way this organization works today.
He contributed to the globalisation of research at CERN and was also responsible for the return of Spain and Portugal in the CERN's member states.
Schopper is professor emeritus at the University of Hamburg since 1989. From 1992 to 1994 he was president of the German Physical Society and president of the European Physical Society in 1995–97. For many years he was member of the scientific council of the Joint Institute for Nuclear Research in Dubna and of the board of trustees of the Max Planck Institute for Plasma Physics in Garching.
At UNESCO, he served as member of the Physics Action Council and chairman of the Working Group on Large Facilities, president of the scientific council of the Regional Office for Science and Technology ROSTE of UNESCO in Venice (2001–2002) and in 2003–2009 he was the chairman of the international advisory committee for the International Basic Science Programs.
Schopper's vision of science without borders resulted in him becoming a founding father of SESAME, the laboratory for Synchrotron-Light for Experimental Science and Applications in the Middle East, which provides an extremely bright light source to investigate a broad range of domains from condensed matter to biology and archeology. In 1999–2008 he became president of the Preliminary International Council and later, after the formal foundation of SESAME, of the International Council. Without his dedication this international research facility would probably not have been built. SESAME was founded analogous to CERN, under the umbrella of UNESCO, with presently nine member states: Bahrain, Cyprus, Egypt, Iran, Israel, Jordan, Pakistan, the Palestinian Authority and Turkey. It provides an environment where countries with different political systems, traditions, religions and mentalities are able to work together peacefully.
Schopper is a founding member of The Cyprus Institute at Nicosia, Cyprus, and since 2000 Member of the board of trustees and was chairman of the Scientific Council and member of the executive committee of the board of trustees of the Cyprus Institute.
Currently, he works as an advisor and goodwill ambassador on science for peace. He writes articles about research policy, science and religion and also science and society.
Honours and awards
Honorary academic degrees
Schopper received honorary doctoral degrees from: University of Erlangen (1982), Moscow State University (1988), University of Geneva (1989), University of London, Joint Institute for Nuclear Research (Dubna) (1999), Institute for High Energy Physics (Protvino), The Cyprus Institute (Nicosia) (2018) and the Karlsruhe Institute of Technology (KIT) (2024).
Awards
Physics Prize of Göttingen Academy of Sciences and Humanities (1957)
Carus Medal of the Academy of Sciences Leopoldina in Halle (1957)
Ritter-von-Gerstner-Medal (1978)
Großer Sudetendeutscher Kulturpreis (1984)
Golden Plate Award of the American Academy of Achievement (USA) (1985)
Gold Medal of the Weizmann Institute (Israel) with CERN (1985)
Grosses Bundesverdienstkreuz of the Federal Republik Germany (1989)
Wilhelm Exner Medal (Austria) (1991)
J.E.Purkyne Memorial Medal of the Czech Academy of Sciences (1994)
Order of Friendship of the Russian Federation awarded by President Yeltsin (1996)
Grand Cordon of the Order of Independence awarded by King Abdullah II of Jordan (2003)
Tate Medal of the American Institute of Physics (2003)
UNESCO Albert Einstein Gold Medal, Denmark (2004)
Silver Medal of SESAME International Council (2004)
UNESCO Niels Bohr Gold Medal (2005)
Scientific Merit Medal, Portugal (2009)
Physics Medal of first grade of the Czech Physical Society and Union of Czech Mathematicians and Physicists (2010)
Grand Cross of the Order of Merit of the Republic of Cyprus (2012)
Golden Honorary Needle of DESY (Hamburg) (2013)
AAAS Award for Science Diplomacy (2019)
Goldmedal of the Heisenberg Society (2024)
Memberships
Academy of Sciences Leopoldina in Halle
Academia Europaea in London
Academia Scientiarium et Artium Europea in Salzburg
Corresponding member of the Bavarian Academy of Sciences in Munich
Honorary member of the Hungarian Academy of Sciences
Fellow of the Institute of Physics in London
Fellow of the American Physical Society
Academy of Sciences in Lisbon
Member and trustee of the World Academy of Art and Science in San Francisco
Honorary Member of the Swiss Physical Society
Honorary Member of European Physical Society
Honorary Member of the German Physical Society
Honorary Member of the Polish Academy of Sciences
Publications and books
Scientific publications
Schopper wrote more than 200 original publications in optics, nuclear physics, elementary particle physics and accelerator technology. Some of the most important works are:
Fleischmann R. and H. Schopper, The determination of the optical constants and thickness of the layer of absorbent layers by means of the measurement of the absolute phase change Z.Physik 129.285 (1951) (first method for the measurement of the absolute phase upon reflection of light on the thin metal layers)
H. Schopper, The interpretation of the optical constants of alkali metals, Z.Physik 135, 163 (1953) (the abnormal optical behaviour of thin alkali metal layers does not require a special physical state of the metal)
H. Schopper, Circular polarization of gamma rays: Further proof for parity failure in beta-decay, Phil.Mag.' 2, 710 (1957) (One of the experiments proposed by Lee and Yang, but considered impossible. In this experiment it was shown for the first time that the helicity of the neutrino and antineutrino are opposite.)
G. Clausnitzer, R. Fleischmann and H. Schopper, Production of a hydrogen atom beam with parallel nuclear spins, Z.Physik 144, 336 (1956)
H. Schopper and S. Galster, The circular polarization of internal and external bremsstrahlung, Nucl.Phys. 6, 125 (1958) (first measurement of the circular polarization of the internal bremsstrahlung of beta decay)
J. Halbritter, R. Hietschold, P. Kneisel, and H. Schopper, Coupling losses and the measurement of Q-values of superconducting cavities, KFK-report Karlsruhe 3 / 86-6 (1968) (early publication of the study of superconducting cavities to accelerate particles)
R. M. Littauer, H. Schopper, R. R. Wilson, Electromagnetic properties of the proton and neutron, Phys. Rev. Lett. 6, 286 (1961), Phys. Rev. Lett. 7, 141 (1961) and 7, 144 (1961) (measurement of nuclear form factors, improvement of the first measurements by R. Hofstadter)
Behrend et al., Elastic electron-proton scattering at momentum transfers up to 110 fermi-2, Nuov.Cim. 48.140 (1967)
J. Engler, W. Flauger, AS. Gibbard, F. Mönnig, K. Runge and H. Schopper, A total absorption spectrometer for energy measurements of high-energy particles, Nucl.Instr.Meth. 106, 189 (1973) (first usage and optimization of a 'hadron calorimeter')
V. Boehmer et al., Neutron-proton elastic scattering from 10 to 70 GeV / c, Nucl.Phys. B91, 266 (1975) and other publications (neutron-proton scattering at high energies, the ISR at CERN and at the Institute for High Energy Physics in Protvino, Russia)
L3 Collaboration, Upsilon production in Z decays, Phys.Lett. B 413, 167 (1997) and Heavy Quarkonium Production in Z decays, CERN-PPE/92-99 and Phys.Lett.B (Schopper was principal author of these publications)
H.Schopper, The light of SESAME: A dream becomes reality, La Rivista del Nuovo Cimento, 40, 199 (2017)
Books
H. Schopper, Weak Interactions and Nuclear Beta Decay, North-Holland Publishing (1966)
H. Schopper, Matter and Antimatter'', Pieper Verlag (1989)
H. Schopper, LEP — The Lord of the Rings Collider at CERN 1980–2000, Springer Verlag (2009); with a foreword by Rolf-Dieter Heuer; ; e-book
Editor of Springer Materials, Landolt-Bornstein, Nuclear and Particle Physics
H. Schopper and L. Di Lella, editors, 60 years of CERN Experiments and Discoveries, World Scientific (2015); pbk
Co-editor of several other books
See also
List of Directors General of CERN
Scientific publications of Herwig Schopper on INSPIRE-HEP
References
1924 births
Living people
People from Lanškroun
20th-century German physicists
People associated with CERN
Commanders Crosses of the Order of Merit of the Federal Republic of Germany
Experimental particle physics
German nuclear physicists
International Centre for Synchrotron-Light for Experimental Science Applications in the Middle East people
Members of the European Academy of Sciences and Arts
Members of the Hungarian Academy of Sciences
UNESCO Niels Bohr Medal recipients
Academic staff of the University of Hamburg
German expatriates in Sweden
German expatriates in the United Kingdom
Presidents of the European Physical Society
Presidents of the German Physical Society
Fellows of the American Physical Society
Academic staff of the Karlsruhe Institute of Technology
German men centenarians | Herwig Schopper | [
"Physics"
] | 3,050 | [
"Experimental physics",
"Particle physics",
"Experimental particle physics"
] |
10,917,433 | https://en.wikipedia.org/wiki/Drobo | Drobo was a manufacturer of a series of external storage devices for computers, including DAS, SAN, and NAS appliances. Drobo devices can house up to four, five, eight, or twelve 3.5" or 2.5" Serial ATA or Serial Attached SCSI hard disk drives and connect with a computer or network via USB 2.0, USB 3.0, FireWire 800, eSATA, Gigabit Ethernet or Thunderbolt. Drobo devices are primarily designed to allow installation and removal of hard disk drives without requiring manual data migration, for increasing storage capacity of the unit without downtime, and for data protection against drive failure.
The company Drobo, Inc. changed its name from Data Robotics in 2011 since the familiarity with the Drobo name (which had only been the name of their product line until then) far exceeded the Data Robotics name. Drobo, Inc. merged with Connected Data, Inc. in June 2013, with the new company taking the Connected Data name. In May 2015, the storage appliance business was spun-off as Drobo, Inc. and acquired by an investment group composed of seasoned tech executives Drobo was later acquired by StorCentric in August, 2018.
All Drobo products had been out of stock or severely inventory constrained in both the Drobo Store and retail channels since the beginning of 2020. Drobo initially blamed this on supply chain issues caused by the COVID-19 pandemic. In November, 2021, Drobo stated that more devices would be available in "the next few months". In June 2022, StorCentric filed for Chapter 11 bankruptcy. After failing to find a buyer or reorganize the company, it shifted to Chapter 7 bankruptcy in April 2023.
From the Drobo website: As of January 27th, 2023, Drobo support and products are no longer available. Drobo support has transitioned to a self-service model. The knowledge base, documentation repository, and legacy documentation library are still accessible for your support needs. We thank you for being a Drobo customer and entrusting us with your data.
As of February 8, 2024, the Drobo website at www.drobo.com is no longer accessible.
Products
Overview
Consumer models
* Plus one mSATA SSD slot for Data-Aware Tiering
**Plus one 128 GB mSATA SSD card for Data-Aware Tiering
***Plus one 2.5" SATA SSD bay for Data-Aware Tiering
Business models
References
External links
Computer storage devices
Linux-based devices
Computer storage companies
Server appliance
Companies that filed for Chapter 11 bankruptcy in 2022
Companies that have filed for Chapter 7 bankruptcy
Companies that filed for Chapter 7 bankruptcy in 2023
Defunct computer companies of the United States
Defunct computer hardware companies | Drobo | [
"Technology"
] | 585 | [
"Computer storage devices",
"Recording devices"
] |
10,918,014 | https://en.wikipedia.org/wiki/Willibald%20Jentschke | Willibald Jentschke (6 December 1911 – 11 March 2002) was an Austrian-German experimental nuclear physicist.
During World War II, he made contributions to the German nuclear energy project.
After World War II, he emigrated to the United States to work at Wright-Patterson Air Force Base, in Ohio, for the Air Force Materiel Command.
In 1950, he became a professor at the University of Illinois at Urbana–Champaign, where he became director of the Cyclotron Laboratory there in 1951.
In 1956, he became a professor of physics at the University of Hamburg and spearheaded the effort to build the 7.5 GeV electron synchrotron DESY, the foundation of which was in December 1959. He was director of DESY for 10 years. In 1971, he became Director General of CERN Laboratory I for the next five years. He retired from the University of Hamburg in 1980.
Education
Jentschke studied physics at the University of Vienna, from 1930 to 1936. He received his doctorate under Georg Stetter in 1935. Jentschke joined the Nazi Party in 1941.
Career
From 1937 to 1942, Jentschke was a teaching assistant to Georg Stetter at the University of Vienna. From 1942 to 1945, he was a lecturer at the University of Vienna. During World War II, Jentschke was also (Scientific Assistant) at the II. Physikalisches Institut der Universität, Wien (Second Physics Institute of the University of Vienna), where Georg Stetter was the director. One of Jentschke's colleagues there was Josef Schintlmeister. The Institute did research on transuranic elements and measurement of nuclear constants, in collaboration with the Institut für Radiumforschung (Institute for Radium Research) of the Österreichischen Adademie der Wissenschaften (Austrian Academy of Sciences). This work was done under the German nuclear energy project, also known as the Uranverein (Uranium Club); see, for example, the publications cited below under Internal Reports.
In 1939, John Archibald Wheeler and Niels Bohr proposed the liquid-drop model of nuclear fission. Their work suggested that uranium 235 was responsible for thermal neutron fission. This was borne out by the work of Eugene T. Booth, John R. Dunning, A. V. Grosse, and Alfred O. C. Nier, which was submitted for publication in the spring of 1940. Jentschke, F. Prankl, and F. Hernegger also substantiated the Bohr-Wheeler claims shortly after the American work by observing the phenomenon in an isotope of thorium, thorium 230.
From 1946 to 1947, Jentschke was a lecturer at the University of Innsbruck.
Near the close and after the end of World War II in Europe, the Russians and the Western powers had programs to foster technology transfer and exploit German technical specialists. For example, the U.S. had Operation Paperclip and the Russians had trophy brigades advancing with their military forces. In the area of atomic technology, the U.S. had Operation Alsos and the Russians had their version. While operational aspects of the Russian operation were modeled after the trophy brigades, a more refined approach was warranted for the exploitation of German atomic related facilities, intellectual materials, and scientific personnel. This was rectified with a decree in late 1944 and the formation of specialize exploitation teams in early 1945 under the Russian Alsos, which had broader objectives, which included wholesale relocation of scientific facilities to the Soviet Union.
Jentschke emigrated to the United States under Operation Paperclip, where he worked at the Air Force Materiel Command (today, the Air Force Logistics Command after merger with the Air Force Systems Command in 1992), at Wright-Patterson Air Force Base, Ohio, from 1947 to 1948. On his way to the United States, Jentschke wrote to Walther Bothe that his reasons for going there was to do real scientific work, which then not possible in Austria and Germany.
In 1950, Jentschke became a resident assistant professor, and in 1955 resident professor, in the Department of Physics at the University of Illinois at Urbana–Champaign. In 1951, he became director of the Cyclotron Laboratory there.
During 1956 and 1957, Jentschke was a member of the Arbeitskreis Kernphysik (Nuclear Physics Working Group) of the Fachkommission II "Forschung und Nachwuchs" (Commission II "Research and Growth") of the Deutschen Atomkommission (DAtK, German Atomic Energy Commission). Other members of the Nuclear Physics Working Group in both 1956 and 1957 were: Werner Heisenberg (chairman), Hans Kopfermann (vice-chairman), Fritz Bopp, Walther Bothe, Wolfgang Gentner, Otto Haxel, Heinz Maier-Leibnitz, Josef Mattauch, , Wilhelm Walcher, and Carl Friedrich von Weizsäcker. Wolfgang Paul was also a member of the group during 1957.
In 1956, Jentschke became an ordinarius Professor of Physics at the University of Hamburg. There, he found a positive climate, as well as funding, for his vision of building a new institute around a particle accelerator. An international particle accelerator conference at CERN in 1956 was helpful in the decision of which accelerator to build. His vision could not be supported by Hamburg alone, so negotiations took place to bring in support of the Federal Republic of Germany and the states of Germany (Länder). A financial agreement was signed on 18 December 1959, which founded the Deutsches Elektronen-Synchrotron (DESY), a 7.5 GeV electron synchrotron. Jentschke was chairman of the DESY Board of Directors from 1959 to 1970, and for many years also the director of the Second Institute of Experimental Physics at the University of Hamburg. While at DESY, Jentschke endorsed the electron-positron storage ring scheme for the DORIS accelerator, and promoted the use of synchrotron radiation for research purposes.
In 1971, Jentschke accepted the post as Director General of CERN Laboratory I (the Meyrin site); John Adams was Director General of the neighboring CERN Laboratory II (Prévessin), where the new SPS proton synchrotron was being constructed. They shared the directorship of CERN until the two laboratories were united in 1976. While Director General, Jentschke oversaw the exploitation of the new research tool, the Intersecting Storage Rings, which began operation in 1971.
Jentschke retired from the University of Hamburg in 1980.
Honors
Professor Jentschke was the recipient of a number of honors:
Wilhelm Exner Medal in 1971.
Member, Akademie der Wissenschaften und Literatur (In German), Mainz
Corresponding Member, Österreichische Akademie der Wissenschaften, Vienna
Honorary Doctor's Degree, University of Illinois
Honorary Doctor's Degree, RWTH Aachen, 1990
John T.Tate Award of the American Institute of Physics, 1996
A street, Route Jentschke, on the CERN Meyrin site, is named after him.
Internal reports
The following reports were published in Kernphysikalische Forschungsberichte (Research Reports in Nuclear Physics), an internal publication of the German Uranverein. The reports were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. The reports are available at the Karlsruhe Nuclear Research Center and the American Institute of Physics.
Willibald Jentschke and F. Prankl Energien und Massen der Urankernbruchstücke (August 1940) G-44.
Willibald Jentschke Energien und Massen der Urankernbrüchstücke bei Bestrahlung mit schnellen (Rn + Be)-Neutronen (16 September 1941) G-99.
Selected bibliography
Willibald Jentschke, F. Prankl, and F. Hernegger Die Spaltung des Ioniums under Neutronenebestrahlung, Die Naturwissenschaften Volume 28, Issue 20, 315–316 (1940)
Willibald Jentschke and Friedlich Prankl Energien und Massen der Urankernbruchstücke bei Bestrahlung mit vorwiegend thermischen Neutronen, Zeitschrift für Physik Volume 119, Numbers 11–12, 696–712 (1942). Received 27 June 1942. Jentschke was identified as being at the II. Physikalisches Institut der Universität Wien, Wien and Prankl was identified as being at the Institut für Radiumforschung, Österreich.
Willibald Jentschke Energien und Massen der Urankernbruchstücke bei Bestrahlung mit Neutronen, Zeitschrift für Physik Volume 120, Numbers 3–4, 165–184 (1943). Received 18 September 1942. Jentschke was identified as being the II. Physikalisches Institut d. Universität, Wien.
References
Further reading
Willibald Jentschke – Biografi (DESY)
Gimbel, John Science, Technology, and Reparations: Exploitation and Plunder in Postwar Germany (Stanford University Press, 1990)
Gimbel, John U.S. Policy and German Scientists: The Early Cold War, Political Science Quarterly Volume 101, Number 3, 433–451 (1986)
Hentschel, Klaus (editor) and Ann M. Hentschel (editorial assistant and translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996)
Jacob, Maurice CERN loses two former Director-General, CERN Bulletin Issue No. 19 (6 May 2002)
Naimark, Norman M. The Russians in Germany: A History of the Soviet Zone of Occupation, 1945–1949 (Belknap, 1995)
Oleynikov, Pavel V. German Scientists in the Soviet Atomic Project, The Nonproliferation Review Volume 7, Number 2, 1 – 30 (2000). The author has been a group leader at the Institute of Technical Physics of the Russian Federal Nuclear Center in Snezhinsk (Chelyabinsk-70).
Walker, Mark German National Socialism and the Quest for Nuclear Power 1939–1949 (Cambridge, 1993)
1911 births
2002 deaths
20th-century Austrian physicists
Austrian nuclear physicists
People associated with CERN
Experimental physicists
German nuclear physicists
Nuclear program of Nazi Germany
Particle physicists
Scientists from Vienna
University of Vienna alumni
Academic staff of the University of Vienna
Academic staff of the University of Innsbruck
University of Illinois Urbana-Champaign faculty
Academic staff of the University of Hamburg
Operation Paperclip
20th-century German physicists
Austrian emigrants to the United States
Nazi Party members
Austrian Nazis | Willibald Jentschke | [
"Physics"
] | 2,322 | [
"Particle physicists",
"Experimental physics",
"Experimental physicists",
"Particle physics"
] |
10,918,148 | https://en.wikipedia.org/wiki/Lightning-prediction%20system | A lightning prediction system is a type of lightning detection equipment that determines when atmospheric conditions likely to produce lightning strikes and sounds an alarm, warning those nearby that lightning is imminent and giving them the chance to find safety before the storm arrives in the area. Lightning protection systems are often installed in outdoor areas which are often congested with people, lack sufficient shelter, and are difficult to evacuate quickly (such as water parks, college campuses, and large swimming pool or athletic field complexes). These locations are particularly dangerous during lightning storms. Prediction systems are prone to false alarms as they respond to conditions that are not always attributed to a developing thunderstorm. Electric field data is typically used in conjunction with detection information to limit false positives.
Description
The detection equipment is designed to constantly survey atmospheric electrical activity and potential for lightning occurrence via radar and other methods. Storms are scanned by radar to determine the degree of electrification and potential for lightning occurrence.
The method used by such systems includes the stationing of at least three receivers at known locations in order to triangulate their data. When any of the receivers detects a strong electrical disturbance, the location is shared with other receivers in the area for corroboration, and then (presuming the data has passed the filters), encoded and transmitted to a central facility and thereafter processed for deriving the position of the lightning strike. By detecting thunderstorm electrical fields, a track can be predicted to allow warnings as early as 30 minutes before lightning strikes the protected area. The system is synchronized with the U.S. Coast Guard LORAN navigation network, and includes various features which permit a more accurate analysis of lightning position.
While some systems require manual remote activation of the siren from the central monitoring facility, others work automatically. These systems can also sound an "All Clear" tone when electrical activity in the monitored area has receded to safe levels. This feature eliminates both the need for skilled monitoring of the system as well as the chance for human error in interpreting the data.
See also
Early warning system
Franklin bells
Lightning
de:Blitz#Ortung
es:Detector de rayos
fr:Détecteur de foudre
ja:雷検知器
pl:Wykrywacz piorunów
fi:Salamatutka | Lightning-prediction system | [
"Physics",
"Materials_science",
"Astronomy"
] | 456 | [
"Physical phenomena",
"Materials science stubs",
"Astronomy stubs",
"Astrophysics",
"Astrophysics stubs",
"Electrical phenomena",
"Lightning",
"Electromagnetism stubs"
] |
10,918,229 | https://en.wikipedia.org/wiki/Stellacyanin | Stellacyanin is a member of the blue or type I copper protein family. This family of copper proteins is generally involved in electron transfer reactions with the Cu center transitioning between the oxidized Cu(II) form and the reduced Cu(I) form. Stellacyanin is ubiquitous among vascular seed plants.
Structure
Stellacyanin’s spectroscopic properties help us differentiate it from plastocyanin, which is another monocopper blue protein found in plants. It is a 20kDa protein whose structure is made up of beta strands forming two beta sheets to form a Greek key beta barrel with variable alpha helical structure. The copper binding domain of the protein is located at the amino-terminal end, while the carboxyl-terminal end is rich in hydroxyproline and serine residues, typical of proteins associated with cell walls of plants. In addition, it is also heavily glycosylated. The copper is tetrahedrally coordinated by a cysteine, 2 histidines, and a glutamine residue. The glutamine residue takes place of a methionine ligand typically found in other blue copper proteins. In addition, electron transfer rates for stellacyanin are faster than for other type I copper proteins suggesting stellacyanin is more solvent accessible at the active site. The exact function of stellacyanin is unknown. However, given the fact that type I copper proteins are involved in electron transfer and stellacyanin appears to be associated with the plant cell wall, it is suggested that it is involved in oxidative cross-linking reactions to build polymeric material making up the cell wall. Cell wall structural glycoproteins contain hydroxyproline and serine-rich sequence domains which are found in stellacyanins.
Stellacyanin Reduction Potential
Stellacyanins are characterized by their uniquely low redox potentials, as low as +180 mv and reach up to +280 mV. Other blue copper protein redox potentials start around +310 mV and reach up to +680 mV. A mutant cucumber stellacyanin was created by replacing the glutamine axial ligand (a ligand which all other blue proteins contain) with a methionine (Q99M) and purified. This was achieved through Polymerase Chain Reaction (PCR). The mutated stellacyanin calculated redox potential was +420 mV, which much higher than the redox potential of the stellacyanin found in nature (without methionine) at +260 mV. Stellacyanins are most involved in redox reactions of plants that take place during a defense response, and formation of lignin.
References
Copper proteins
Plant proteins | Stellacyanin | [
"Chemistry"
] | 569 | [
"Biochemistry stubs",
"Protein stubs"
] |
10,919,113 | https://en.wikipedia.org/wiki/Protein%20L | Protein L was first isolated from the surface of bacterial species Peptostreptococcus magnus and was found to bind immunoglobulins through L chain interaction, from which the name was suggested. It consists of 719 amino acid residues. The molecular weight of protein L purified from the cell walls of Peptostreptoccus magnus was first estimated as 95kD by SDS-PAGE in the presence of reducing agent 2-mercaptoethanol, while the molecular weight was determined to 76kD by gel chromatography in the presence of 6 M guanidine HCl. Protein L does not contain any interchain disulfide loops, nor does it consist of disulfide-linked subunits. It is an acidic molecule with a pI of 4.0. Unlike protein A and protein G, which bind to the Fc region of immunoglobulins (antibodies), protein L binds antibodies through light chain interactions. Since no part of the heavy chain is involved in the binding interaction, Protein L binds a wider range of antibody classes than protein A or G. Protein L binds to representatives of all antibody classes, including IgG, IgM, IgA, IgE and IgD. Single chain variable fragments (scFv) and Fab fragments also bind to protein L.
Despite this wide binding range, protein L is not a universal antibody-binding protein. Protein L binding is restricted to those antibodies that contain kappa light chains. In humans and mice, most antibody molecules contain kappa (κ) light chains and the remainder have lambda (λ) light chains. Protein L is only effective in binding certain subtypes of kappa light chains. For example, it binds human VκI, VκIII and VκIV subtypes but does not bind the VκII subtype. Binding of mouse immunoglobulins is restricted to those having VκI light chains.
Given these specific requirements for effective binding, the main application for immobilized protein L is purification of monoclonal antibodies from ascites or cell culture supernatant that are known to have the kappa light chain. Protein L is extremely useful for purification of VLκ-containing monoclonal antibodies from culture supernatant because it does not bind bovine immunoglobulins, which are often present in the media as a serum supplement. Also, protein L does not interfere with the antigen-binding site of the antibody, making it useful for immunoprecipitation assays, even using IgM.
Gene for protein L
The gene for protein L contains five components: a signal sequence of 18 amino acids; a NH2-terminal region ("A") of 79 residues; five homologous "B" repeats of 72-76 amino acids each; a COOH terminus region of two additional "C" repeats (52 amino acids each); a hydrophilic, proline-rich putative cell wall-spanning region ("W") after the C repeats; a hydrophobic membrane anchor ("M"). The B repeats (36kD) were found to be responsible for the interaction with Ig light chains.[2]
Other antibody binding proteins
In addition to protein L, other immunoglobulin-binding bacterial proteins such as protein A, protein G and protein A/G are all commonly used to purify, immobilize or detect immunoglobulins. Each of these immunoglobulin-binding proteins has a different antibody binding profile in terms of the portion of the antibody that is recognized and the species and type of antibodies it will bind.
References
Proteins
Immunology | Protein L | [
"Chemistry",
"Biology"
] | 761 | [
"Immunology",
"Biomolecules by chemical classification",
"Proteins",
"Molecular biology"
] |
10,919,195 | https://en.wikipedia.org/wiki/Fermat%20Prize | The Fermat prize of mathematical research biennially rewards research works in fields where the contributions of Pierre de Fermat have been decisive:
Statements of variational principles
Foundations of probability and analytic geometry
Number theory.
The spirit of the prize is focused on rewarding the results of research accessible to the greatest number of professional mathematicians within these fields. The Fermat prize was created in 1989 and is awarded once every two years in Toulouse by the Institut de Mathématiques de Toulouse. The amount of the Fermat prize has been fixed at 20,000 Euros for the twelfth edition (2011).
Previous prize winners
Pierre Fermat medal
There has also been a Pierre Fermat medal, which has been awarded for example to chemist Linus Pauling (1957), mathematician Ernst Peschl (1965) and botanist Francis Raymond Fosberg.
Junior Fermat Prize
The Junior Fermat Prize is a mathematical prize, awarded every two years to a student in the first four years of university for a contribution to mathematics. The amount of the prize is 2000 Euros.
See also
List of mathematics awards
References
External links
Fermat Prize official web site
Junior Fermat Prize official web site
Annales de la faculté des sciences de Toulouse
Mathematics awards
Awards established in 1989
Variational principles
. | Fermat Prize | [
"Mathematics",
"Technology"
] | 265 | [
"Mathematical principles",
"Variational principles",
"Discrete mathematics",
"Mathematics awards",
"Science and technology awards",
"Number theory"
] |
10,919,454 | https://en.wikipedia.org/wiki/XXTEA | In cryptography, Corrected Block TEA (often referred to as XXTEA) is a block cipher designed to correct weaknesses in the original Block TEA.
XXTEA is vulnerable to a chosen-plaintext attack requiring 259 queries and negligible work. See cryptanalysis below.
The cipher's designers were Roger Needham and David Wheeler of the Cambridge Computer Laboratory, and the algorithm was presented in an unpublished technical report in October 1998 (Wheeler and Needham, 1998). It is not subject to any patents.
Formally speaking, XXTEA is a consistent incomplete source-heavy heterogeneous UFN (unbalanced Feistel network) block cipher. XXTEA operates on variable-length blocks that are some arbitrary multiple of 32 bits in size (minimum 64 bits). The number of full cycles depends on the block size, but there are at least six (rising to 32 for small block sizes). The original Block TEA applies the XTEA round function to each word in the block and combines it additively with its leftmost neighbour. Slow diffusion rate of the decryption process was immediately exploited to break the cipher. Corrected Block TEA uses a more involved round function which makes use of both immediate neighbours in processing each word in the block.
XXTEA is likely to be more efficient than XTEA for longer messages.
Needham & Wheeler make the following comments on the use of Block TEA:
For ease of use and general security the large block version is to be preferred when applicable for the following reasons.
A single bit change will change about one half of the bits of the entire block, leaving no place where the changes start.
There is no choice of mode involved.
Even if the correct usage of always changing the data sent (possibly by a message number) is employed, only identical messages give the same result and the information leakage is minimal.
The message number should always be checked as this redundancy is the check against a random message being accepted.
Cut and join attacks do not appear to be possible.
If it is not acceptable to have very long messages, they can be broken into chunks say of 60 words and chained analogously to the methods used for DES.
However, due to the incomplete nature of the round function, two large ciphertexts of 53 or more 32-bit words identical in all but 12 words can be found by a simple brute-force collision search requiring 296−N memory, 2N time and 2N+296−N chosen plaintexts, in other words with a total time*memory complexity of 296, which is actually 2wordsize*fullcycles/2 for any such cipher. It is currently unknown if such partial collisions pose any threat to the security of the cipher. Eight full cycles would raise the bar for such collision search above complexity of parallel brute-force attacks.
The unusually small size of the XXTEA algorithm would make it a viable option in situations where there are extreme constraints e.g. legacy hardware systems (perhaps embedded) where the amount of available RAM is minimal, or alternatively single-board computers such as the Raspberry Pi, Banana Pi or Arduino.
Cryptanalysis
An attack published in 2010 by E. Yarrkov presents a chosen-plaintext attack against full-round XXTEA with wide block, requiring 259 queries for a block size of 212 bytes or more, and negligible work. It is based on differential cryptanalysis.
To cipher "212 bytes or more" algorithm performs just 6 rounds, and carefully chosen bit patterns allows to detect and analyze avalanche effect.
Reference code
The original formulation of the Corrected Block TEA algorithm, published by David Wheeler and Roger Needham, is as follows:
#define DELTA 0x9e3779b9
#define MX ((z>>5^y<<2) + (y>>3^z<<4) ^ (sum^y) + (k[p&3^e]^z))
long btea(long* v, long n, long* k) {
unsigned long z=v[n-1], y=v[0], sum=0, e, DELTA=0x9e3779b9;
long p, q ;
if (n > 1) { /* Coding Part */
q = 6 + 52/n;
while (q-- > 0) {
sum += DELTA;
e = (sum >> 2) & 3;
for (p=0; p<n-1; p++) y = v[p+1], z = v[p] += MX;
y = v[0];
z = v[n-1] += MX;
}
return 0 ;
} else if (n < -1) { /* Decoding Part */
n = -n;
q = 6 + 52/n;
sum = q*DELTA ;
while (sum != 0) {
e = (sum >> 2) & 3;
for (p=n-1; p>0; p--) z = v[p-1], y = v[p] -= MX;
z = v[n-1];
y = v[0] -= MX;
sum -= DELTA;
}
return 0;
}
return 1;
}
According to Needham and Wheeler:
Note that the initialization of z is Undefined behavior for n < 1 which may cause a segmentation fault or other unwanted behavior – it would be better placed inside the 'Coding Part' block. Also, in the definition of MX some programmers would prefer to use bracketing to clarify operator precedence.
A clarified version including those improvements is as follows:
#include <stdint.h>
#define DELTA 0x9e3779b9
#define MX (((z>>5^y<<2) + (y>>3^z<<4)) ^ ((sum^y) + (key[(p&3)^e] ^ z)))
void btea(uint32_t *v, int n, uint32_t const key[4]) {
uint32_t y, z, sum;
unsigned p, rounds, e;
if (n > 1) { /* Coding Part */
rounds = 6 + 52/n;
sum = 0;
z = v[n-1];
do {
sum += DELTA;
e = (sum >> 2) & 3;
for (p=0; p<n-1; p++) {
y = v[p+1];
z = v[p] += MX;
}
y = v[0];
z = v[n-1] += MX;
} while (--rounds);
} else if (n < -1) { /* Decoding Part */
n = -n;
rounds = 6 + 52/n;
sum = rounds*DELTA;
y = v[0];
do {
e = (sum >> 2) & 3;
for (p=n-1; p>0; p--) {
z = v[p-1];
y = v[p] -= MX;
}
z = v[n-1];
y = v[0] -= MX;
sum -= DELTA;
} while (--rounds);
}
}
See also
RC4: A stream cipher that, just like XXTEA, is designed to be very simple to implement.
XTEA: Block TEA's precursor.
TEA: XTEA's precursor.
References
External links
a JavaScript implementation
a PHP implementation
a CL implementation
Broken block ciphers
Computer security in the United Kingdom
Feistel ciphers
History of computing in the United Kingdom
Science and technology in Cambridgeshire
Articles with example C code | XXTEA | [
"Technology"
] | 1,614 | [
"History of computing",
"History of computing in the United Kingdom"
] |
10,921,599 | https://en.wikipedia.org/wiki/Quadrangle%20%28architecture%29 | In architecture, a quadrangle (or colloquially, a quad) is a space or a courtyard, usually rectangular (square or oblong) in plan, the sides of which are entirely or mainly occupied by parts of a large building (or several smaller buildings). The word is probably most closely associated with college or university campus architecture, but quadrangles are also found in other buildings such as palaces. Most quadrangles are open-air, though a few have been roofed over (often with glass), to provide additional space for social meeting areas or coffee shops for students.
The word quadrangle was originally synonymous with quadrilateral, but this usage is now relatively uncommon.
Some modern quadrangles resemble cloister gardens of medieval monasteries, called garths, which were usually square or rectangular, enclosed by covered arcades or cloisters. However, it is clear from the oldest examples (such as Mob Quad) which are plain and unadorned with arcades, that the medieval colleges at Oxford and Cambridge were creating practical accommodation for college members. Grander quadrangles that look like cloisters came later, once the idea of a college was well established and benefactors or founders wished to create more monumental buildings. Although architectonically analogous, for historical reasons quads in the colleges of the University of Cambridge are always referred to as courts (such as the Trinity Great Court).
In North America, Thomas Jefferson's design for the University of Virginia centered the housing and academic buildings in a Palladian form around three sides of the Lawn, a huge grassy expanse. Later, some American college and university planners imitated the Jeffersonian plan, the Oxbridge idea, Beaux-Arts forms, and other models. All five barracks at The Citadel (military college) feature quadrangles with red-and-white squares (the colors of the South Carolina battle flag), which are used for formations by the Corps of Cadets.
Quadrangles are also found in traditional Kerala houses (Naalukettu) and is known as the Nadumittam ("Middle Space").
Notable quadrangles
Woodburn Circle, West Virginia University
Blue Boar Quadrangle, Christ Church, Oxford
Francis Quadrangle, University of Missouri
Memorial Quadrangle, Yale University
Mob Quad, Merton College, Oxford is one of the oldest quads in existence.
Peckwater Quadrangle, Christ Church, Oxford
Killian Court, Massachusetts Institute of Technology
The Quad, Harvard University
Harvard Yard, Harvard University
Queen's Lawn, Imperial College London
The Quad, University of the West Indies at St Augustine
The Green, Dartmouth College
King's College Quad, University of Aberdeen
The Quadrangle, Springfield, Massachusetts
Radcliffe Quadrangle, University College, Oxford
Schenley Quadrangle, University of Pittsburgh
Bascom Hill, University of Wisconsin–Madison
Tom Quad, Christ Church, Oxford University
University of Alabama Quad
The Quad, University College London
Founder's Building, Royal Holloway College, London
The Diag, University of Michigan
Sunken Garden, College of William & Mary
The Lawn, University of Virginia
McKeldin Mall, University of Maryland
Old College, University of Edinburgh
New College, University of Edinburgh
Holyrood Quad, Moray House, Edinburgh
Dahlgren Quadrangle, Georgetown University
Old Campus, Yale University
Main Quad, Stanford University
Law Quadrangle, University of Michigan
Liberal Arts Quadrangle, University of Washington
West Chester State College Quadrangle Historic District, West Chester University
The Quadrangle, University of Pennsylvania
El Cuadrángulo, University of Puerto Rico, Río Piedras
Whitworth Hall Quadrangle, University of Manchester
Hearn Plaza, Wake Forest University
Quadrangle, S.Thomas' College, Mount Lavinia
See also
Haveli, a form of classical architecture from South Asia & Persia, which incorporates a quad for cooling ventilation in the hot climate, and the private enjoyment of the open sky by residents, in a very modest culture
Notes
Architectural elements
Quadrangle (architecture)
University and college buildings
Campuses | Quadrangle (architecture) | [
"Technology",
"Engineering"
] | 803 | [
"Building engineering",
"Architectural elements",
"Components",
"Architecture"
] |
10,921,962 | https://en.wikipedia.org/wiki/Cytoscape | Cytoscape is an open source bioinformatics software platform for visualizing molecular interaction networks and integrating with gene expression profiles and other state data. Additional features are available as plugins. Plugins are available for network and molecular profiling analyses, new layouts, additional file format support and connection with databases and searching in large networks. Plugins may be developed using the Cytoscape open Java software architecture by anyone and plugin community development is encouraged. Cytoscape also has a JavaScript-centric sister project named Cytoscape.js that can be used to analyse and visualise graphs in JavaScript environments, like a browser.
History
Cytoscape was originally created at the Institute of Systems Biology in Seattle in 2002. Now, it is developed by an international consortium of open source developers. Cytoscape was initially made public in July, 2002 (v0.8); the second release (v0.9) was in November, 2002, and v1.0 was released in March 2003. Version 1.1.1 is the last stable release for the 1.0 series. Version 2.0 was initially released in 2004; Cytoscape 2.83, the final 2.xx version, was released in May 2012. Version 3.0 was released Feb 1, 2013, and the latest version, 3.4.0, was released in May 2016.
Development
The Cytoscape core developer team continues to work on this project and released Cytoscape 3.0 in 2013. This represented a major change in the Cytoscape architecture; it is a more modularized, expandable and maintainable version of the software.
Usage
While Cytoscape is most commonly used for biological research applications, it is agnostic in terms of usage. Cytoscape can visualize and analyze network graphs of any kind involving nodes and edges (e.g., social networks). A vital aspect of the software architecture of Cytoscape is the use of plugins for specialized features. Plugins are developed by core developers and the greater user community.
See also
Computational genomics
Graph drawing
JavaScript framework
JavaScript library
Metabolic network modelling
Protein–protein interaction prediction
References
External links
https://cytoscape.org/screenshots.html
Cytoscape wiki
Cytoscape omictools webpage
Bioinformatics software
Systems biology
Mathematical and theoretical biology
Graph drawing software
Cross-platform software
Java platform software | Cytoscape | [
"Mathematics",
"Biology"
] | 498 | [
"Mathematical and theoretical biology",
"Bioinformatics software",
"Applied mathematics",
"Bioinformatics",
"Systems biology"
] |
10,922,177 | https://en.wikipedia.org/wiki/British%20Museum%20leather%20dressing | British Museum leather dressing has been used by many conservators since its publication to protect and conserve leather.
Formulation
The basic formulation is:
The first three ingredients are heated together, then added to the cold solvent and allowed to cool while constantly stirring. Care should be exercised, as the solvents are highly flammable and have low boiling points.
Variations
There are several variations in the formulation.
Sometimes 60% of the lanolin was replaced by neatsfoot oil.
One disadvantage of the solvent hexane is its tendency to evaporate rapidly. Before the fat/hexane mixture has been able to penetrate deep into the leather, the hexane evaporates to the surface of the leather, taking most of the fat with it.
While beeswax prevents air pollutants from penetrating the leather, it does this by closing off the leather, thus disturbing the water balance and causing the leather to dry out. The cedarwood oil acts as a fungicide to further protect the leather.
In use
The British Museum leather dressing was part of an elaborate leather conservation programme. Other steps entailed cleaning the leather, if necessary with soap and water, and applying an aqueous solution of 7% potassium lactate as a buffer. A warning was given about the dangers of using too much lactate, which made books sticky and could cause fungal growth. The books had to be absolutely dry when the leather dressing was applied.
The dressing would be applied sparingly and rubbed into the leather. After two days, the treated leather was polished with a soft cloth. Hard leathers can be soaked in a solution of one part British Museum leather dressing: three parts Stoddard solvent.
British Museum leather dressing darkens leather, but it is a treatment with a good success record.
References
Leather dressing
Leather crafting
Conservation and restoration materials | British Museum leather dressing | [
"Physics"
] | 373 | [
"Materials",
"Matter",
"Conservation and restoration materials"
] |
10,922,431 | https://en.wikipedia.org/wiki/Renaissance%20Wax | Renaissance Wax is a brand of microcrystalline wax polish used in antique restoration and museum conservation around the world. Commonly used to polish and conserve metal objects, it is also used on gemstones and such organic materials as wood, ivory, and tortoiseshell. The product is sometimes used by reenactors to protect armor and weapons. Waxes are more protective and longer-lasting than oil, especially for swords and helmets that are frequently touched by human hands. It has recently been introduced in the world of guitar building, as a finish that protects and gives colour to the wood.
Wax coatings for conservation are most widely, and least controversially, applied to metals. This has several objectives: to produce a barrier that excludes moisture and oxygen from the metal surface, to preclude the introduction of contaminating elements by handling, and to provide a protective layer over anti-corrosion undercoatings.
Microcrystalline waxes used on ethnographic metal objects are discouraged, as they may require extensive treatment for removal.
Renaissance wax is used to protect metals such as silver, brass and copper from tarnishing, on collections of all types of metals (old coins, locks and keys, arms and armour both original and replica), on both the wood and metal surfaces of vintage cars and musical instruments, on bronze sculptures inside the home and outside exposed to the elements, on marble and granite worktops to prevent staining and on smooth leather items.
Formulation
Renaissance Wax was developed in the British Museum Research Laboratory by Dr A E A Werner in the late 1950s. It is manufactured by Picreator Enterprises Ltd.
Earlier wax polishes based on beeswax and carnauba wax either contained acids or became acidic over time. Renaissance Wax is based on more stable microcrystalline waxes refined from crude oil.
Renaissance Wax contains polyethylene waxes. Some other microcrystalline waxes intended for conservation use do not contain these.
Use
The wax is evenly and lightly applied over the surface, then lightly buffed with a smooth lint-free cloth or brush.
Application over other coatings
Renaissance Wax applied over Klucel G or a similar material used in retarding red rot in leather bookbindings can create an irremovable white residue if applied too heavily. Use of a different wax, such as SC6000, is recommended for leather.
Renaissance Wax is also commonly used in the preservation of bronze and copper coins. The wax seals the coins and helps prevent deterioration from moisture and air exposure. It may also help prevent the onset of the chloride-related corrosion commonly called bronze disease, although it won't arrest this once started.
Conservation of metals may also involve the application of an undercoat such as Incralac followed by the application of Renaissance Wax.
Accumulation of dust and lint
Wax coatings, in general, may accumulate dust and lint.
In one example where a Benin bust made from a copper-iron alloy had been coated with multiple materials including this wax, the polyethylene component required a higher-temperature solvent for removal than the rest of the wax.
See also
Conservation-restoration of cultural heritage
References
Waxes
Conservation and restoration materials | Renaissance Wax | [
"Physics"
] | 652 | [
"Materials",
"Conservation and restoration materials",
"Matter",
"Waxes"
] |
10,922,862 | https://en.wikipedia.org/wiki/Honeywagon%20%28vehicle%29 | A honeywagon or honeycart is the slang term for a "vacuum truck" for collecting and carrying human excreta. These vehicles may be used to empty the sewage tanks of buildings, aircraft lavatories, passenger train toilets and at campgrounds and marinas as well as portable toilets. The folk etymology behind the name 'honeywagon' is thought to relate to the honey-colored liquid that comes out of it when emptying the holding tanks.
History
The honey wagon was originally a horse-drawn vehicle that went through back alleys to collect human excreta. Houses at that time did not have flush toilets or indeed any form of indoor sanitation beyond the chamberpot. In rural areas the outhouse (privy) is associated with a pit latrine of various sorts, but many towns and cities depended on some variant of the pail closet, which needed frequent emptying. At each outdoor toilet, the driver (honey dipper) would stop the wagon, flip up the back hatch door (trap-door) of the outhouse, slide out the pail (bucket), pick it up, and dump the contents into one of eight oak half-barrels in the wagon box. The half-barrels had no lids. These toilets were known as dunnies in Australia, hence the "dunnywagon" driven by "dunnymen".
Use in film and television industry
A honeywagon is a portable toilet unit used in the film and television industry. Many take the form of a specialized semi-trailer.
In the UK a honeywagon usually refers to a set of toilets used by the cast and crew. These come in all shapes and sizes - either trailer-base or built into the box body of a truck. In America, the term honeywagon is usually given to a truck, trailer or combination of both with a number of dressing rooms for the actor. These either have individual toilets or a communal set built in. Some honeywagons will be just two large toilets. Others are a combination of variously sized rooms for specific purposes: these rooms can be private dressing rooms assigned to a single person, larger rooms configured for the wardrobe, or makeup departments, small individual toilets for the crew to share, and multiple user or individual shower rooms for bathing.
Operation
The operator connects a hose to the discharge outlet on the recreational vehicle, boat or building and pumps the waste into the wagon's holding tank. When the tank is full, the operator empties the tank at an approved holding tank dump station or sewage lagoon.
See also
Honey bucket, another name for a bucket toilet
Manual scavenging
Manure spreader
References
Waste collection vehicles
Pumps
Toilets | Honeywagon (vehicle) | [
"Physics",
"Chemistry",
"Biology"
] | 545 | [
"Pumps",
"Turbomachinery",
"Excretion",
"Physical systems",
"Hydraulics",
"Toilets"
] |
10,923,101 | https://en.wikipedia.org/wiki/Stillman%20diet | The Stillman diet is a high-protein, low-carbohydrate diet devised in 1967 by physician Irwin Maxwell Stillman (1896–1975). It focusses mostly on the complete avoidance of both fats and carbohydrates, and requires at least eight glasses of water to be consumed every day. The diet is very low in fiber, vitamins and minerals, and cuts out bread, fruit, sugar, and alcohol completely.
It was popularized in the late 60's with the publication of Stillman and Samm Sinclair Baker's book, The Doctor's Quick Weight Loss Diet, although it was criticized by some physicians who believed that the diet was unbalanced and could negatively affect users.
Overview
Stillman and Samm Sinclair Baker co-authored the book The Doctor's Quick Weight Loss Diet that first advertised the Stillman Diet in 1967. The animal based high-protein diet includes lean beef, veal, chicken, turkey, fish, eggs and non-fat cottage cheese. Spices, tabasco sauce, herbs, salt, and pepper are also allowed. Condiments, butter, dressings and any kind of fat or oil are not permitted. Tea, coffee, and non-caloric soft drinks can be consumed, but only in addition to the 8 daily glasses of water required. It's also recommended that dieters eat 6 small meals per day instead of 3 large ones.
The diet is a carbohydrate-restricted diet, similar to that of Dr. Robert Atkins', Atkins Diet (although Atkins' diet allows significant fat consumption).
Karen Carpenter
Karen Carpenter began using the diet in her teens. Karen was 5'4" and 145 pounds when she went on the Stillman Diet in 1967. In 1983, she died of complications related to anorexia nervosa.
Reception
The Stillman diet has been criticized by medical experts and nutritionists as a fad diet. Physician Terrence T. Kuske wrote regarding the Stillman diet:
It induces a degree of diuresis because of the low carbohydrate, but is a relatively unpalatable diet. Adherence to the diet induces fatigue, nausea and lassitude or exhaustion. Long-term use of this diet, because of its composition, may induce vitamin deficiency. Studies of individuals following the Stillman Diet have demonstrated quite conclusively that it raises the serum cholesterol, with its attendant risks.
See also
List of diets
Scarsdale diet
References
Further reading
Low-carbohydrate diets
Fad diets
High-protein diets | Stillman diet | [
"Chemistry"
] | 529 | [
"Carbohydrates",
"Low-carbohydrate diets"
] |
10,923,250 | https://en.wikipedia.org/wiki/Southern%20marsupial%20mole | The southern marsupial mole (Notoryctes typhlops), also known as the itjaritjari () or itjari-itjari, is a mole-like marsupial found in the western central deserts of Australia. It is extremely adapted to a burrowing way of life. It has large, shovel-like forepaws and silky fur, which helps it move easily. It also lacks complete eyes as it has little need for them. It feeds on earthworms and larvae.
History of discovery
Although the southern marsupial mole was probably known by Aboriginal Australians for thousands of years, the first specimen examined by the scientific community was collected in 1888. Stockman W. Coulthard made the discovery on Idracowra Pastoral Lease in the Northern Territory by following some unusual prints that led him to the animal lying under a tussock. Not knowing what to do with the strange creature, he wrapped it in a kerosene soaked rag, placed it in a revolver cartridge box and forwarded it to E. C. Stirling, the Director of the South Australian Museum. Due to the poor transportation conditions of the time, the specimen reached its destination in a badly decomposed state. Hence, Stirling was unable to find any evidence of the pouch or epipubic bones and decided the creature was not a marsupial.
Nineteenth century scientists believed that marsupials and eutherians had evolved from the same primitive ancestor and were looking for a living specimen that would serve as the missing link. Because the marsupial mole closely resembled the golden moles of Africa, some scientists concluded that the two were related and that they had found the proof. This, however, is not the case, as became obvious by examining better-preserved specimens that had a marsupial pouch. The striking similarities of the two species are, in fact, the result of convergent evolution.
Taxonomy and phylogeny
Although the family Notoryctidae is poorly represented in the fossil record there is evidence of at least one distinct genus Yalkaparidon, in the early Miocene sediments in the Riversleigh deposit in northern Australia.
Due to their highly specialized morphology and the fact that notoryctids share many common characteristics with other marsupials, there has been much debate surrounding their phylogeny. However, recent molecular studies indicate that notoryctids are not closely related to any of the other marsupial families and should be placed in an order of their own, Notoryctemorphia.
Furthermore, molecular data suggests that Notoryctemorphia separated from other marsupials around 64 million years ago. Although at this time South America, Antarctica and Australia were still joined the order evolved in Australia for at least 40-50 million years. The Riversleigh fossil material suggests that Notoryctes was already well adapted for burrowing and probably lived in the rainforest that covered much of Australia at that time. The increase in aridity at the end of Tertiary was likely one of the key contributing factors to the development of the current highly specialized form of marsupial mole. The marsupial mole had been burrowing long before the Australian deserts came into being.
Morphology
The southern marsupial mole is small in size, with a head and body length of , a tail length of and a weight of . The body is covered with short, dense, silky fur with a pale cream to white color often tinted by the iron oxides from the soil which gives it a reddish chestnut brown tint. It has a light brownish pink nose and mouth and no vibrissae.
The cone shaped head merges directly with the body, and there is no obvious neck region. The limbs are short and powerful, and digits III and IV of the manus have large spade-like claws. The dentition varies with individuals and, because the molars have a root of only one third of the length, it has been assumed that moles cannot deal with hard food substances.
The dorsal surface of the rostrum and the back of the tail have no fur and the skin is heavily keratinized. There is no external evidence of the eyes, and the optic nerve is absent. It does, however, have a pigment layer where the eyes should be, probably a vestige of the retina. Both lachrymal glands and Jacobson's organ are well developed, and it has been suggested that the former plays a role in lubricating the nasal passages and Jacobson's organ.
The external ear openings are covered with fur and do not have pinnae. The nostrils are small vertical slits right below the shield-like rostrum. Although the brain has been regarded as very primitive and represents the "lowliest marsupial brain", the olfactory bulbs and the tubercula olfactoria are very well developed. This seems to suggest that the olfactory sense plays an important role in the marsupial mole’s life, as it would be expected for a creature living in an environment lacking visual stimuli. The middle ear seems to be adapted for the reception of low-frequency sounds.
Adaptations
In an example of convergent evolution, the southern marsupial mole resembles the Namib Desert golden mole (Eremitalpa granti namibensis) and other specialised fossorial animals in having a low and unstable body temperature, ranging between . It does not have an unusually low resting metabolic rate, and the metabolic rate of burrowing is 60 times higher than that of walking or running. Because it lives underground, where the temperature is considerably lower than at the surface, the southern marsupial mole does not seem to have any special adaptations to desert life. It is not known whether it drinks water or not, but due to the irregularity of rainfall it is assumed that it does not.
Habitat and distribution
The habitat of the southern marsupial mole is not well known, and is generally based on scattered records. It has been often recorded in sandy dunes or flats, usually where spinifex is present. Its habitat seems to be restricted to areas where the sand is soft, as it cannot tunnel through harder materials. Although little is known about its exact distribution, sightings, aboriginal informants and museum records indicate that it lives in the central sandy desert regions of Western Australia, northern South Australia and the Northern Territory. Recent studies indicate that its habitat also includes Great Victoria and Gibson Deserts.
Behavior
Due to the lack of any field studies regarding the marsupial moles, there is little known about their behavior. Observations of captive animals are limited since most of the moles do not survive much longer than a month after capture.
Surface behavior
It sometimes wanders above the surface where traces of several animals have been found. While most evidence indicates that it does this seldom and moves just a few meters before burrowing back underground, on some occasions multiple tracks were found suggesting that one or more animals have moved above ground for several hours. According to Aboriginal sources, marsupial moles may surface at any time of day, but seem to prefer to do so after rain and in the cooler season.
Captive animals have been observed to feed above ground and then return underground to sleep. Occasionally it has been recorded to suddenly "faint" on the surface without waking up for several hours until disturbed.
Above the ground it moves in a sinuous fashion, using its powerful forelimbs to haul the body over the surface and its hind limbs to push forward. The forelimbs are extended forward in unison with the opposite hind limb. Moles move about the surface with frantic haste but little speed, as one observer once likened it to a "Volkswagen Beetle heaving its way through the sand".
Burrowing behavior
While burrowing, the southern marsupial mole does not make permanent tunnels, but the sand caves in and tunnels back-fill as the animal moves along. For this reason its burrowing style has been compared to "swimming through the sand”". The only way its tunnels can be identified is as a small oval shape of loose sand. Although it spends most of its active time 20-100 cm below the surface, tunneling horizontally or at shallow angles, it sometimes for no apparent reason turns suddenly and burrows vertically to depths of up to 2.5 meters.
Although most food sources are likely to occur at depths of approximately 50 cm from the surface, the temperature of these environments varies greatly from less than 15°C during winter to over 35°C during summer. While one of the captive moles was observed shivering when the temperature dropped under 16°C, it seems probable that moles can select the temperature of their environment by burrowing at different depths.
Diet
Little is known about the southern marsupial mole's diet, and all information is based on the gut content of preserved animals and on observations made on captive specimens. All evidence seems to suggest that the mole is mainly insectivorous, preferring insect eggs, larvae and pupae to the adults. Based on observations made on captive animals, it seems that one of the favorite food choices was beetle larvae, especially Scarabaeidae. Because burrowing requires high energy expenditure it seems unlikely that the mole searches for its food in this prey impoverished environment, and suggests that it probably feeds within nests. It has been also recorded to eat adult insects, seeds and lizards. Below the desert sands of Australia, the marsupial mole searches for burrowing insects and small reptiles. Instead of building a tunnel, it "swims" through the ground, allowing the sand to collapse behind it.
Social behavior
There is little known about the social and reproductive behavior of these animals, but all evidence seems to suggest that it leads a solitary life. There are no traces of large burrows where more than one individual might meet and communicate. Although it is not known how the male locates the female, it is assumed that they do so using their highly developed olfactory sense.
The fact that the middle ear seems to be morphologically suited for capturing low frequency sounds, and that moles produce high pitched vocalizations when handled, indicates that this kind of sound that propagates more easily underground may be used as a form of communication.
Human interactions
The southern marsupial mole was known for thousands of years to Australia’s Indigenous people and was part of their mythology. It was associated with certain sites and dreaming trails such as Uluru and the Anangu-Pitjantjatjara Lands. They were regarded with sympathy, probably due to its harmless nature, and were only eaten during hard times.
Aboriginal people have good tracking skills and generally cooperate with researchers in teaching them these skills and help finding specimens. Their involvement is instrumental in gathering information about the species’ habitat and behavior.
Historical records suggest that the southern marsupial mole was relatively common in the late 19th century and early 20th century. There was a large trade in marsupial mole skins in the Finke River region between 1900 and 1920. Large numbers of aborigines arrived at the trading post with 5-6 pelts each for sale to trade for food and other commodities. It is estimated that hundreds to several thousand skins were traded at these meetings, and that at the time the mole was relatively common.
Conservation status
So little is known about the southern marsupial mole that it is difficult to assess its exact distribution and how it varied over the last decades. However circumstantial evidence suggests that their numbers are dwindling. Although the decreasing acquisition rate is difficult to interpret due to the chance nature of the findings, there are reasons for concern. About 90% of medium-sized marsupials in arid Australia have become threatened due to cat and fox predation. A recent study indicates that remains of marsupial moles have been found in 5% of the cats and foxes faecal pellets examined. Moles are also sensitive to changes in the availability of their food caused by changing fire regimes and the impact of herbivores. The southern marsupial mole is currently listed as endangered by the IUCN. Efforts to protect this species focus on advocating for maintaining a healthy population of moles to better understand their biology and behavior, and for conducting field studies to monitor the species distribution and abundance with the help of Aborigines.
References
External links
Facts and Status from Arkive
Marsupial Mole from marsupialsociety.org
Southern Marsupial Mole from environment.gov.au
Notoryctidae
Marsupials of Australia
Mammals of South Australia
Mammals of the Northern Territory
EDGE species
Endangered fauna of Australia
Mammals described in 1889
Species that are or were threatened by invasive species
Taxa named by Edward Charles Stirling | Southern marsupial mole | [
"Biology"
] | 2,571 | [
"EDGE species",
"Biodiversity"
] |
10,923,676 | https://en.wikipedia.org/wiki/Apple%20Multimedia%20Lab | The Apple Multimedia Lab was a pioneering electronic media research group operated by Apple Computer. It was founded in 1987 by cognitive psychologist Kristina Hooper Woolsey and educational psychologist Sueann Ambron.
References
Multimedia
Communication design
Mass media companies of the United States | Apple Multimedia Lab | [
"Technology",
"Engineering"
] | 49 | [
"Multimedia",
"Design",
"Communication design"
] |
10,923,902 | https://en.wikipedia.org/wiki/Dream%20Pool%20Essays | The Dream Pool Essays (or Dream Torrent Essays) was an extensive book written by the Chinese polymath and statesman Shen Kuo (1031–1095), published in 1088 during the Song dynasty (960–1279) of China. Shen compiled this encyclopedic work while living in forced retirement from government office, naming the book after his private estate near modern Zhenjiang, Jiangsu province. The Dream Pool Essays was heavily reorganized in reprint editions by later Chinese authors from the late 11th to 17th centuries. In modern times it has been translated from Chinese into several languages. These include English, German, French, and Japanese translations.
The Dream Pool Essays covers a range of topics including discoveries and advancements in Traditional Chinese medicine, mathematics, astronomy, science and technology, optics, architecture and civil engineering, metallurgy, and early archaeology. Observations of the natural world included those of wildlife, meteorology, hypotheses advancing early ideas in geomorphology and climate change based on findings of petrification and natural erosion, and strange recorded phenomena such as the description of an unidentified flying object. In addition to establishing the theory of true north in magnetic declination towards the north pole, Shen was also the first to record the use of a compass for navigation, the first to describe the invention of movable type printing by contemporary artisan Bi Sheng, and the first in China to describe a drydock for repairing boats out of water.
History
Shen Kuo was a renowned government official and military general during the Northern Song period of China. However, he was impeached from office by chancellor Cai Que (蔡確; 1036–1093), who wrongly held him responsible for a Song Chinese military defeat by the Tangut-led Western Xia dynasty in 1081 during the Song–Xia wars. When Shen compiled and published The Dream Pool Essays (Meng Xi Bi Tan, 《梦溪笔谈》) in 1088, he was living in retirement and relative isolation on his lavish garden estate near modern-day Zhenjiang, Jiangsu province. He titled the book after the name he gave to his private estate, the "Dream Brook". In English a full literal translation of the title is Brush Talks from a Dream Brook, and Shen Kuo is quoted as saying:
As the historian Chen Dengyuan points out, much of Shen Kuo's written work was probably purged under the leadership of minister Cai Jing (1046–1126). For example, only six of Shen's books remain, and four of these have been significantly altered since the time they were penned by the author. The Dream Pool Essays was first quoted in a Chinese written work of 1095 AD, showing that even towards the end of Shen's life his final book was becoming widely printed. The book was originally 30 chapters long, yet an unknown Chinese author's edition of 1166 AD edited and reorganized the work into 26 chapters. There is one surviving copy of this 1166 edition now in Japan, while a Chinese reprint was produced in 1305. In 1631 another edition was printed, but it was heavily reorganized into three broad chapters.
In modern times, Zhang Jiaju's biographical work Shen Kuo (1962) contains selected translations of the Dream Pool Essays from Middle Chinese into modern Vernacular Chinese. The Dream Pool Essays has also been translated from Chinese into various foreign languages. Various volumes of Joseph Needham's Science and Civilization in China series published since 1954 contain a large amount of selected English translations of the Dream Pool Essays. The Brush Talks from Dream Brook is the first complete English translation, presented in two volumes by translators Wang Hong and Zhao Zheng, and published in 2008 by the Sichuan People's Publishing House, China. A Japanese translation of the 1166 Chinese edition was prepared by the History of Science Seminar, Institute for Research in Humanities (Jimbun Kagaku Kenkyusho) for Kyoto University, and printed by the author Umehara Kaoru in his 3-volume edition of Bokei hitsudan (1978–1981). Quoted excerpts from the Dream Pool Essays in French were printed in the written works of J. Brenier in 1989 and J. F. Billeter in 1993. A complete German translation is offered in Shen Kuo: Pinselunterhaltungen am Traumbach. Das Gesamte Wissen des Alten China, translated and edited by Konrad Herrmann, and published in 1997 by Diederichs Verlag Munich (Gelbe Reihe Magnum, vol. I).
Quotes
Geological theory
With Shen's writings on fossils, geomorphology, and shifting geographical climates, he states in the following passages:
In the Zhi-ping reign period [1064–67 AD] a man of Zezhou was digging a well in his garden, and unearthed something shaped like a squirming serpent, or dragon. He was so frightened by it that he dared not touch it, but after some time, seeing that it did not move, he examined it and found it to be stone. The ignorant country people smashed it, but Zheng Boshun, who was magistrate of Jincheng at the time, got hold of a large piece of it on which scale-like markings were to be seen exactly like those on a living creature. Thus a serpent or some kind of marine snake (chhen) had certainly been turned to stone, as happens with the 'stone-crabs'.Chan, 15.
In recent years [cca. 1080] there was a landslide on the bank of a large river in Yong-ning Guan near Yanzhou. The bank collapsed, opening a space of several dozens of feet, and under the ground a forest of bamboo shoots was thus revealed. It contained several hundred bamboo with their roots and trunks all complete, and all turned to stone...Now bamboos do not grow in Yanzhou. These were several dozens of feet below the present surface of the ground, and we do not know in what dynasty they could possibly have grown. Perhaps in very ancient times the climate was different so that the place was low, damp, gloomy, and suitable for bamboos. On the Jin-hua Shan in Wuzhou there are stone pine-cones, and stones formed from peach kernels, stone bulrush roots, stone fishes, crabs, and so on, but as these are all (modern) native products of that place, people are not very surprised at them. But these petrified bamboos appeared under the ground so deep, though they are not produced in that place today. This is a very strange thing.Needham, Volume 3, 614.
Astronomy
When the Director of the Astronomical Observatory asked Shen Kuo if the shapes of the sun and moon were round like balls or flat like fans, Shen Kuo explained his reasoning for the former:
If they were like balls they would surely obstruct each other when they met. I replied that these celestial bodies were certainly like balls. How do we know this? By the waxing and waning of the moon. The moon itself gives forth no light, but is like a ball of silver; the light is the light of the sun (reflected). When the brightness is first seen, the sun(-light passes almost) alongside, so the side only is illuminated and looks like a crescent. When the sun gradually gets further away, the light shines slanting, and the moon is full, round like a bullet. If half of a sphere is covered with (white) powder and looked at from the side, the covered part will look like a crescent; if looked at from the front, it will appear round. Thus we know that the celestial bodies are spherical.
When the director of the astronomical observatory asked Shen Kuo why eclipses occurred only on an occasional basis while in conjunction and opposition once a day, Shen Kuo wrote:
I answered that the ecliptic and the moon's path are like two rings, lying one over the other, but distant by a small amount. (If this obliquity did not exist), the sun would be eclipsed whenever the two bodies were in conjunction, and the moon would be eclipsed whenever they were exactly in position. But (in fact) though they may occupy the same degree, the two paths are not (always) near (each other), and so naturally the bodies do not (intrude) upon one another.
On the use of the sighting tube to fix the position of the pole star, Shen Kuo wrote:
Before Han times it was believed that the pole star was in the center of the sky, so it was called Jixing (Summit star). Zu Geng(-zhi) found out with the help of the sighting tube that the point in the sky which really does not move was a little more than 1 degree away from the summit star. In the Xining reign-period (1068–1077) I accepted the order of the emperor to take charge of the Bureau of the Calendar. I then tried to find the true pole by means of the tube. On the very first night I noticed that the star which could be seen through the tube moved after a while outside the field of view. I realized, therefore, that the tube was too small, so I increased the size of the tube by stages. After three months' trials I adjusted it so that the star would go round and round within the field of view without disappearing. In this way I found that the pole star was distant from the true pole somewhat more than 3 degrees. We used to make the diagrams of the field, plotting the positions of the star from the time when it entered the field of view, observing after nightfall, at midnight, and early in the morning before dawn. Two hundred of such diagrams showed that the 'pole star' was really a circumpolar star. And this I stated in my detailed report to the emperor.
Movable type printing
On the methods of Bi Sheng's invention of movable type printing between the years 1041 to 1048 AD, Shen Kuo wrote:
[Bi Sheng] took sticky clay and cut in it characters as thin as the edge of a coin. Each character formed, as it were, a single type. He baked them in the fire to make them hard. He had previously prepared an iron plate and he had covered his plate with a mixture of pine resin, wax, and paper ashes. When he wished to print, he took an iron frame and set it on the iron plate. In this he placed the types, set close together. When the frame was full, the whole made one solid block of type. He then placed it near the fire to warm it. When the paste [at the back] was slightly melted, he took a smooth board and pressed it over the surface, so that the block of type became as even as a whetstone. If one were to print only two or three copies, this method would be neither simple nor easy. But for printing hundreds or thousands of copies, it was marvelously quick. As a rule he kept two forms going. While the impression was being made from the one form, the type was being put in place on the other. When the printing of the one form was finished, the other was then ready. In this way the two forms alternated and the printing was done with great rapidity.
Personal beliefs and philosophy
Of Taoism and the inability of empirical science to explain everything in the world, Shen Kuo wrote:
Those in the world who speak of the regularities underlying the phenomena, it seems, manage to apprehend their crude traces. But these regularities have their very subtle aspect, which those who rely on mathematical astronomy cannot know of. Still even these are nothing more than traces. As for the spiritual processes described in the [Book of Changes] that "when they are stimulated, penetrate every situation in the realm," mere traces have nothing to do with them. This spiritual state by which foreknowledge is attained can hardly be sought through changes, of which in any case only the cruder sort are attainable. What I have called the subtlest aspect of these traces, those who discuss the celestial bodies attempt to know by depending on mathematical astronomy; but astronomy is nothing more than the outcome of conjecture.
Dissertation on the Timberwork Manual
Below are two passages from Shen's book outlining the basics contained in Yu Hao's Timberwork Manual. Yu Hao was a Chinese architect of the earlier 10th, and Kuo was one to praise his work. In the first quote, Shen Kuo describes a scene where Yu Hao gives advice to another artisan architect about slanting struts for diagonal wind bracing:
When Mr. Qian (Wei-yan) was Governor of the two Zhejiang provinces, he authorized the building of a wooden pagoda at the Fan-tian Si (Brahma-Heaven Temple) in Hangzhou with a design of twice three stories. While it was under construction General Chhien went up to the top and was worried because it swayed a little. But the Master-Builder explained that as the tiles had not yet been put on, the upper part was still rather light, hence the effect. So then they put on all the tiles, but the sway continued as before. Being at a loss what to do, he privately sent his wife to see the wife of Yu Hao with a present of golden hair pins, and enquire about the cause of the motion. (Yu) Hao laughed and said: 'That's easy, just fit in struts (pan) to settle the work, fixed with (iron) nails, and it will not move any more.' The Master-Builder followed his advice, and the tower stood quite firm. This is because the nailed struts filled in and bound together (all the members) up and down so that the six planes (above and below, front and back, left and right) were mutually linked like the cage of the thorax. Although people might walk on the struts, the six planes grasped and supported each other, so naturally there could be no more motion. Everybody acknowledged the expertise thus shown.
In this next quote, Shen Kuo describes the dimensions and types of architecture outlined in Yu Hao's book:
Methods of building construction are described in the Timberwork Manual, which, some say, was written by Yu Hao. (According to that book), buildings have three basic units of proportion, what is above the cross-beams follows the Upperwork Unit, what is above the ground floor follows the Middlework Unit, and everything below that (platforms, foundations, paving, etc.) follows the Lowerwork Unit. The length of the cross-beams will naturally govern the lengths of the uppermost cross-beams as well as the rafters, etc. Thus for a (main) cross-beam of (8 ft) length, an uppermost cross-beam of (3.5 ft) length will be needed. (The proportions are maintained) in larger and smaller halls. This (2/28) is the Upperwork Unit. Similarly, the dimensions of the foundations must match the dimensions of the columns to be used, as also those of the (side-) rafters, etc. For example, a column (11 ft) high will need a platform (4.5 ft) high. So also for all the other components, corbelled brackets, projecting rafters, other rafters, all have their fixed proportions. All these follow the Middlework Unit (2/24). Now below of ramps (and steps) there are three kinds, steep, easy-going, and intermediate. In places these gradients are based upon a unit derived from the imperial litters. Steep ramps are ramps for ascending which the leading and trailing bearers have to extend their arms fully down and up respectively (ratio 3/35). Easy-going ramps are those for which the leaders use elbow length and the trailers shoulder height (ratio 1/38); intermediate ones are negotiated by the leaders with downstretched arms and trailers at shoulder height (ratio 2/18). These are the Lowerwork Units. The book (of Yu Hao) had three chapters. But builders in recent years have become much more precise and skillful (yen shan) than formerly. Thus for some time past the old Timberwork Manual has fallen out of use. But (unfortunately) there is hardly anybody capable of writing a new one. To do that would be a masterpiece in itself!
Botany and zoology
Shen Kuo described the natural predator insect similarly shaped to the gou-he ("dog-grubs") which preyed upon the agricultural pest infestation of zi-fang, the moth Leucania separata:
In the Yuan-Feng reign period (1078–1085), in the Qingzhou region, an outbreak of zi-fang insects caused serious damage to the crops in the fields in autumn. Suddenly another insect appeared in swarms of thousands and tens of thousands, covering the entire ground area. It was shaped like earth-burrowing gou-he (dog grubs), and its mouth was flanked by pincers. Whenever it met a zi-fang, it would seize it with the pincers and break the poor beast into two bits. Within ten days all the zi-fang had disappeared, so the locality had an abundant harvest. Such kinds of insects have been known since antiquity and the local people call them pang-bu-ken ("not allowing other [insects] to be").
Natural phenomena
Around 1078, Shen Kuo wrote an accurate description of the damaging effects of lightning to buildings and to the specific materials of objects within. Taking an objective and speculative viewpoint, he stated:
A house belonging to Li Shunju was struck by lightning. Brilliant sparkling light was seen under the eaves. Everyone thought that the hall would be burnt, and those who were inside rushed out. After the thunder had abated, the house was found to be alright, though its walls and the paper on the windows were blackened. On certain wooden shelves, certain lacquered vessels with silver mouths had been struck by the lightning, so that the silver had melted and dropped to the ground, but the lacquer was not even scorched. Also, a valuable sword made of strong steel had been melted to liquid, without the parts of the house nearby being affected. One would have thought that the thatch and wood would have been burnt up first, yet here were metals melted and no injury to thatch and wood. This is beyond the understanding of ordinary people. There are Buddhist books which speak of 'dragon fire' which burns more fiercely when it meets with water instead of being extinguished by water like 'human' fire. Most people can only judge of things by the experiences of ordinary life, but phenomena outside the scope of this are really quite numerous. How insecure it is to investigate natural principles using only the light of common knowledge, and subjective ideas.
"Strange Happenings"
A passage called "Strange Happenings" contains a peculiar account of an unidentified flying object. Shen wrote that, during the reign of Emperor Renzong (1022–1063), an object as bright as a pearl occasionally hovered over the city of Yangzhou at night, but described first by local inhabitants of eastern Anhui and then in Jiangsu. Shen wrote that a man near Xingkai Lake observed this curious object; allegedly it:
...opened its door and a flood of intense light like sunbeams darted out of it, then the outer shell opened up, appearing as large as a bed with a big pearl the size of a fist illuminating the interior in silvery white. The intense silver-white light, shot from the interior, was too strong for human eyes to behold; it cast shadows of every tree within a radius of ten miles. The spectacle was like the rising Sun, lighting up the distant sky and woods in red. Then all of a sudden, the object took off at a tremendous speed and descended upon the lake like the Sun setting.
Shen went on to say that Yibo, a poet of Gaoyou, wrote a poem about this "pearl" after witnessing it. Shen wrote that since the "pearl" often made an appearance around Fanliang in Yangzhou, the people there erected a "Pearl Pavilion" on a wayside, where people came by boat in hopes to see the mysterious flying object.
Swords
Around 1065 Shen Kuo wrote about the assembly methods for swords, and the patterns produced in the steel:
Ancient people use chi kang, (combined steel), for the edge, and jou thieh (soft iron) for the back, otherwise it would often break. Too strong a weapon will cut and destroy its own edge; that is why it is advisable to use nothing but combined steel. As for the yu-chhang (fish intestines) effect, it is what is now called the 'snake-coiling' steel sword, or alternatively, the 'pine tree design'. If you cook a fish fully and remove its bones, the shape of its guts will be seen to be like the lines on a 'snake-coiling sword'.
Chinese clothing
Shen Kuo observed that the Chinese since some centuries prior had entirely adopted barbarian fashions.
中國衣冠，自北齊以來，乃全用胡服。窄袖、緋綠短衣、長靿靴、有鞢帶，皆胡服也。窄袖利於馳射，短衣、長靿皆便於涉草。胡人樂茂草，常寢處其間，予使北時皆見之。雖王庭亦在深荐中。予至胡庭日，新雨過，涉草，衣褲皆濡，唯胡人都無所沾。帶衣所垂蹀躞，蓋欲佩帶弓劍、帨、算囊、刀勵之類。
The clothing of China since the Northern Qi [550–557] onward has been entirely made barbarian. Narrow sleeves, short dark red or green robes, tall boots and metal girdle ornaments are all barbarian garb. The narrow sleeves are useful when shooting while galloping. The short robes and tall boots are convenient when passing through tall grass. The barbarians all enjoy thick grass as they always sleep in it. I saw them all do it when I was sent north. Even the king's court is in the deep grasses. On the day I had arrived at the barbarian court the new rains had passed and I waded through the grass. My robes and trousers were all soaked, but the barbarians were not at all wet. With things hanging from robe and belt they walk about. One perhaps might want to hang items like a bow and blade, handkerchief, coin purse or knife from the belt.
Book chapters
On the humanities:
Official life and the imperial court (60 paragraphs)
Academic and examination matters (10 paragraphs)
Literary and artistic (70 paragraphs)
Law and police (11 paragraphs)
Military (25 paragraphs)
Miscellaneous stories and anecdotes (72 paragraphs)
Divination, magic, and folklore (22 paragraphs)
On natural sciences:
On the I Ching, Yin and Yang, and 5 elements (7 paragraphs)
Mathematics (11 paragraphs)
Astronomy and calendar (19 paragraphs)
Meteorology (18 paragraphs)
Geology and mineralogy (17 paragraphs)
Geography and cartography (15 paragraphs)
Physics (6 paragraphs)
Chemistry (3 paragraphs)
Engineering, metallurgy, and technology (18 paragraphs)
Irrigation and hydraulic engineering (6 paragraphs)
Architecture (6 paragraphs)
Biological sciences, botany, and zoology (52 paragraphs)
Agricultural arts (6 paragraphs)
Medicine and pharmaceutics (23 paragraphs)
Humanistic sciences:
Anthropology (6 paragraphs)
Archeology (21 paragraphs)
Philology (36 paragraphs)
Music (44 paragraphs)
(Total number of paragraphs = 584)
See also
Chinese classics
Chinese literature
History of science and technology in China
List of Chinese writers
Technology of the Song dynasty
Notes
References
Citations
Bibliography
Bowman, John S. (2000). Columbia Chronologies of Asian History and Culture. New York: Columbia University Press.
Chan, Alan Kam-leung and Gregory K. Clancey, Hui-Chieh Loy (2002). Historical Perspectives on East Asian Science, Technology and Medicine. Singapore: Singapore University Press
Mohn, Peter (2003). Magnetism in the Solid State: An Introduction. New York: Springer-Verlag Inc. .
Needham, Joseph (1986). Science and Civilization in China: Volume 1, Introductory Orientations. Taipei: Caves Books, Ltd.
Needham, Joseph (1986). Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth. Taipei: Caves Books, Ltd.
Needham, Joseph (1986). Science and Civilization in China: Volume 4, Physics and Physical Technology, Part 3: Civil Engineering and Nautics. Taipei: Caves Books, Ltd.
Needham, Joseph (1986). Science and Civilization in China: Volume 5, Chemistry and Chemical Technology, Part 1: Paper and Printing. Taipei: Caves Books, Ltd.
Needham, Joseph (1986). Science and Civilization in China: Volume 6, Biology and Biological Technology, Part 1: Botany. Taipei, Caves Books Ltd.
Sivin, Nathan (1995). Science in Ancient China: Researches and Reflections. Brookfield, Vermont: VARIORUM, Ashgate Publishing.
Ropp, Paul S. (1990). Heritage of China: Contemporary Perspectives on Chinese History. Berkeley: University of California Press.
Further reading
Fu, Daiwie. "On Mengxi Bitan's world of marginalities and “south-pointing needles”. Fragment translation vs. contextual translation". (Archive) In: Alleton, Vivianne and Michael Lackner (editors). De l'un au multiple: traductions du chinois vers les langues européennes Translations from Chinese into European Languages. Éditions de la maison des sciences de l'homme (MSH), 1999, Paris. p. 176–201. , 9782735107681.
Fu, Daiwie. "Mengxi Bitan as an example of organization of knowledge in Song biji." Sinologie française 6 (special issue on the history of science and technology): 269–290.
External links
Shen Kua: mathematician, engineer, physicist, and astronomer
1080s books
Astronomy books
Astronomy in China
Chinese encyclopedias
Science books
Song dynasty literature
Technology books
Leishu
11th-century Chinese books | Dream Pool Essays | [
"Astronomy"
] | 5,499 | [
"Astronomy books",
"Works about astronomy",
"Astronomy in China",
"History of astronomy"
] |
10,924,057 | https://en.wikipedia.org/wiki/Electro-optical%20sensor | Electro-optical sensors are electronic detectors that convert light, or a change in light, into an electronic signal. These sensors are able to detect electromagnetic radiation from the infrared down to the ultraviolet wavelengths. They are used in many industrial and consumer applications, for example:
Lamps that turn on automatically in response to darkness
Position sensors that activate when an object interrupts a light beam
Flash detection, to synchronize one photographic flash to another
Photoelectric sensors that detect the distance, absence, or presence of an object
Function
An optical sensor converts light rays into electronic signals. It measures the physical quantity of light and then translates it into a form readable by an instrument. An optical sensor is generally part of a larger system that integrates a source of light, a measuring device, and the optical sensor. This is often connected to an electrical trigger. The trigger reacts to a change in the signal within the light sensor. An optical sensor can measure the changes from one or several light beams. When a change occurs, the light sensor operates as a photoelectric trigger and therefore either increases or decreases the electrical output.
An optical switch enables signals in optical fibers or integrated optical circuits to be switched selectively between circuits. An optical switch can operate by mechanical means or by electro-optic effects, magneto-optic effects, and other methods.
Types of optical sensors and switches
There are many different kinds of optical sensors, the most common types are:
Photoconductive devices convert a change of incident light into a change of resistance.
Photovoltaics, commonly known as solar cells, convert an amount of incident light into an output voltage.
Photodiodes convert an amount of incident light into an output current.
Phototransistors are a type of bipolar transistor where the base-collector junction is exposed to light. This results in the same behaviour of a photodiode, but with an internal gain.
Optical Switches are usually used in optical fibers, where the electro-optic effect is used to switch one circuit to another. These switches can be implemented with, for example, microelectromechanical systems or piezoelectric systems.
Applications
Electro-optical sensors are used whenever light needs to be converted to energy. Because of this, electro-optical sensors can be seen almost anywhere. Common applications are smartphones where sensors are used to adjust screen brightness, and smartwatches in which sensors are used to measure the wearer's heartbeat.
Optical sensors can be found in the energy field to monitor structures that generate, produce, distribute, and convert electrical power. The distributed and nonconductive nature of optical fibres makes optical sensors perfect for oil and gas applications, including pipeline monitoring. They can also be found in wind turbine blade monitoring, offshore platform monitoring, power line monitoring and downhole monitoring. Other applications include the civil and transportation fields such as bridge, airport landing strip, dam, railway, airplane, wing, fuel tank and ship hull monitoring.
Among other applications, optical switches can be found in thermal methods which vary the refraction index in one leg of an interferometer in order to switch the signal, MEMS approaches involving arrays of micromirrors that can deflect an optical signal to the appropriate receiver, piezoelectric beam steering liquid crystals which rotate polarized light depending on the applied electric field and acousto-optic methods which change the refraction index as a result of strain induced by an acoustic field to deflect light.
Another important application of optical sensor is to measure the concentration of different compounds by both visible and infrared spectroscopy.
See also
Imaging sensor
References
Sensors
Optoelectronics
Nonlinear optics | Electro-optical sensor | [
"Technology",
"Engineering"
] | 736 | [
"Sensors",
"Measuring instruments"
] |
10,924,883 | https://en.wikipedia.org/wiki/Ethylmethylthiambutene | Ethylmethylthiambutene (; Emethibutin) is an opioid analgesic drug from the thiambutene family, around 1.3x the potency of morphine. It is under international control under Schedule I of the UN Single Convention On Narcotic Drugs 1961, presumably due to high abuse potential.
It is a Schedule I controlled substance in the United States with a DEA ACSCN of 9623 and zero annual manufacturing quota as of 2013.
References
Synthetic opioids
Thiophenes
Amines
Mu-opioid receptor agonists | Ethylmethylthiambutene | [
"Chemistry"
] | 125 | [
"Amines",
"Bases (chemistry)",
"Functional groups"
] |
10,925,256 | https://en.wikipedia.org/wiki/G.Skill | G.SKILL International Enterprise is a Taiwanese computer hardware manufacturing company. The company's target customers are overclocking computer users. It produces a variety of high-end PC products and is best known for its DRAM products.
History
Based in Taiwan, G.SKILL corporation was established in 1989. In 2003, the company debuted as a maker of computer memory. The company currently operates through several distributors and resellers in North America, Europe, Asia, and the Middle East.
Products
Memory
G.SKILL is known for its range of DDR, DDR2, DDR3, DDR4 and DDR5 computer memory. RAM is available in single-channel, dual-channel, triple-channel and quad-channel packs for desktops, workstations, HTPC, as well as netbooks and laptops.
It was shown to be the only DDR4 manufacturer not vulnerable to the rowhammer security exploit.
The company does not manufacture the memory dies, it purchases the memory dies and assembles them into a DIMM memory module ready for sale to customers.
In February 2020, G.SKILL announced a DDR4 256 GB memory kit that, unusually for kits of that size at the time, operated at above JEDEC specifications.
Solid-state drive
On 12 May 2008 G.SKILL announced its first SATA II 2.5" solid-state drives (SSDs) with 32 GB or 64 GB of capacity.
On 22 October 2014 G.SKILL released its first Extreme Performance Phoenix Blade Series 480 GB PCIe 2.0 x8 SSD using MLC NAND capable of maximum read and write speeds up to 2,000 MB per second and 245K IOPS.
The company has also produced flash cards in several formats including Secure Digital (SD) and MultiMediaCard (MMC) in addition to high capacity USB 2.0 and 3.0 flash drives.
Peripherals
Mechanical gaming keyboard
On 14 September 2015 G.SKILL announced the availability of the new RIPJAWS series' KM780 RGB and KM780 MX mechanical gaming keyboards with genuine Cherry MX key switches.
Announced on August 21, 2019, G.SKILL announced the KM360 mechanical keyboard with a $49.99 price tag and with Cherry MX red switches (the linear variant).
Laser gaming mouse
On 24 September 2015 G.SKILL released the new RIPJAWS series' MX780 customizable RGB laser gaming mouse.
See also
List of companies of Taiwan
References
External links
G.SKILL Official Website
1989 establishments in Taiwan
Computer companies of Taiwan
Computer hardware companies
Electronics companies established in 1989
Computer memory companies
Electronics companies of Taiwan
Manufacturing companies based in Taipei
Taiwanese brands | G.Skill | [
"Technology"
] | 542 | [
"Computer hardware companies",
"Computers"
] |
10,925,314 | https://en.wikipedia.org/wiki/Enterobactin | Enterobactin (also known as enterochelin) is a high affinity siderophore that acquires iron for microbial systems. It is primarily found in Gram-negative bacteria, such as Escherichia coli and Salmonella typhimurium.
Enterobactin is the strongest siderophore known, binding to the ferric ion (Fe3+) with affinity K = 1052 M−1. This value is substantially larger than even some synthetic metal chelators, such as EDTA (Kf,Fe3+ ~ 1025 M−1). Due to its high affinity, enterobactin is capable of chelating even in environments where the concentration of ferric ion is held very low, such as within living organisms. Pathogenic bacteria can steal iron from other living organisms using this mechanism, even though the concentration of iron is kept extremely low due to the toxicity of free iron.
Structure and biosynthesis
Chorismic acid, an aromatic amino acid precursor, is converted to 2,3-dihydroxybenzoic acid (DHB) by a series of enzymes, EntA, EntB and EntC. An amide linkage of DHB to L-serine is then catalyzed by EntD, EntE, EntF and EntB. Three molecules of the DHB-Ser formed undergo intermolecular cyclization, yielding enterobactin. Although a number of stereoisomers are possible due to the chirality of the serine residues, only the Δ-cis isomer is metabolically active. The first three-dimensional structure of a metal enterobactin complex was determined as the vanadium(IV) complex. Although ferric enterobactin long eluded crystallization, its definitive three-dimensional structure was ultimately obtained using racemic crystallography, in which crystals of a 1:1 mixture of ferric enterobactin and its mirror image (ferric enantioenterobactin) were grown and analyzed by X-ray crystallography.
Mechanism
Iron deficiency in bacterial cells triggers secretion of enterobactin into the extracellular environment, causing formation of a coordination complex "FeEnt" wherein ferric ion is chelated to the conjugate base of enterobactin. In Escherichia coli, FepA in the bacterial outer membrane then allows entrance of FeEnt to the bacterial periplasm. FepB,C,D and G all participate in transport of the FeEnt through the inner membrane by means of an ATP-binding cassette transporter.
Due to the extreme iron binding affinity of enterobactin, it is necessary to cleave FeEnt with ferrienterobactin esterase to remove the iron. This degradation yields three 2,3-dihydroxybenzoyl-L-serine units. Reduction of the iron (Fe3+ to Fe2+) occurs in conjunction with this cleavage, but no FeEnt bacterial reductase enzyme has been identified, and the mechanism for this process is still unclear. The reduction potential for Fe3+/Fe2+–enterobactin complex is pH dependent and varies from −0.57 V (vs NHE) at pH 6 to −0.79 V at pH 7.4 to −0.99 at pH values higher than 10.4.
History
Enterobactin was discovered by Gibson and Neilands groups in 1970. These initial studies established the structure and its relationship to 2,3-dihydroxybenzoic acid.
References
Macrocycles
Siderophores
Salicylamides
Lactones
Twelve-membered rings
Catechols | Enterobactin | [
"Chemistry"
] | 767 | [
"Organic compounds",
"Macrocycles"
] |
5,548,958 | https://en.wikipedia.org/wiki/Bodystorming | Bodystorming is a technique sometimes used in interaction design or as a creativity technique. It has also been cited as catalyzing scientific research when used as a modeling tool.
The idea is to imagine what it would be like if the product existed, and act as though it exists, ideally in the place it would be used. It is going through an idea with improvised artifacts and physical activities to envision a solution. This User Experience Design (UXD) technique is ideal to design physical spaces (e.g. the interior design of a shop) but can also be used to design physical products or software.
Use in Scientific Research
American dance company Black Label Movement's artistic director Carl Flink created a bodystorming system with University of Minnesota biomedical engineer David Odde in 2009 as a part of their Moving Cell Project. funded by the university's Institute for Advanced Study. The system initially brought dance artists and scientists together, including Dance Your PhD founder John Bohannon who first applied the term "bodystorming" to this method, in order to rapid prototype research hypotheses in biomedical engineering using choreographic rules for participants to follow. As a technique for scientists and dancers to model scientific theories, it has been credited with catalyzing scientific research and gives the participants the “psychological sense of what it would be like to be a molecule". Bodystorming sessions have been held at the 2018 Neuro-Oncology Symposium as well as the PSON Annual Investegators Meeting (2019) allowing scientists to use the Bodystorming system to model their current research. It also “offers new opportunities to learn, teach, and drive new discoveries across disciplinary boundaries.” Subsequently, research scientists have found the method not only “builds awareness of science” but understands that the body is “not just a site of knowledge but also a medium of communication.” A typical bodystorming session poses scientific questions then “provides visual information on why a model works or fails and streamlines the process of selecting a successful model.”
Opinions on this method
The proponents of this idea like to point out the fact that you get up and move, trying things out with your own body, rather than just sitting around a table and discussing it while having to imagine it in the abstract (as in the case of brainstorming). It is a proper user-centered design method, since it can be carried out by the designers as well as the users of the final product.
References
Wilson, C. (2011). UXD Method 11 of 100: Bodystorming.
Specific
Creativity techniques
Usability
Human–computer interaction | Bodystorming | [
"Engineering"
] | 531 | [
"Human–computer interaction",
"Human–machine interaction"
] |
5,549,040 | https://en.wikipedia.org/wiki/Methods%20in%20Enzymology | Methods in Enzymology is a book-series of scientific publications focused primarily on research methods in biochemistry by Academic Press, created by Sidney P. Colowick and Nathan O. Kaplan.
Content
Historically, each volume has centered on a specific topic of biochemistry, such as DNA repair, yeast genetics, or the biology of nitric oxide. In recent years, however, the range of topics covered has broadened to also include biotechnology-oriented areas of research.
Each Volume and Chapter includes not only background knowledge but also specific research techniques, detailed experimental procedures and methods. Video elements are also present.
History
First published in 1955, there are (2022) more than 650 volumes in the collection, with ca. 16 new Volumes being published each year.
Editors
The series is currently edited by Anna Marie Pyle (Yale University) and David W. Christianson (University of Pennsylvania) Each volume is guest-edited and contributed to by expert researchers in the field.
References
Biochemistry journals
Academic journals established in 1955
1955 establishments in the United States
Academic Press academic journals | Methods in Enzymology | [
"Chemistry"
] | 212 | [
"Biochemistry stubs",
"Biochemistry journals",
"Biochemistry literature",
"Biochemistry journal stubs"
] |
5,549,114 | https://en.wikipedia.org/wiki/Ammonium%20hexachloroplatinate | Ammonium hexachloroplatinate, also known as ammonium chloroplatinate, is the inorganic compound with the formula (NH4)2[PtCl6]. It is a rare example of a soluble platinum(IV) salt that is not hygroscopic. It forms intensely yellow solutions in water. In the presence of 1M NH4Cl, its solubility is only 0.0028 g/100 mL.
Preparation and structure
The compound consists of separate tetrahedral ammonium cations and octahedral [PtCl6]2− anions. It is usually generated as a fine yellow precipitate by treating a solution of hexachloroplatinic acid with a solution of an ammonium salt. The complex is so poorly soluble that this step is employed in the isolation of platinum from ores and recycled residues.
As analyzed by X-ray crystallography, the salt crystallizes in a cubic motif reminiscent of the fluorite structure. The [PtCl6]2− centers are octahedral. The NH4+ centers are hydrogen bonded to the chloride ligands.
Uses and reactions
Ammonium hexachloroplatinate is used in platinum plating. Heating (NH4)2[PtCl6] under a stream of hydrogen at 200 °C produces platinum sponge. Treating this with chlorine gives H2[PtCl6].
Ammonium hexachloroplatinate decomposes to yield platinum sponge when heated to high temperatures:
3(NH4)2PtCl6 → 3Pt(s) + 2NH4Cl(g) + 16HCl(g) + 2N2(g)
Safety
Dust containing ammonium hexachloroplatinate can be highly allergenic. "Symptoms range from irritation of skin and mucous membranes to life-threatening attacks of asthma."
Related compounds
Potassium hexachloroplatinate
References
Platinum(IV) compounds
Chloro complexes
Ammonium compounds
Hexachloroplatinates | Ammonium hexachloroplatinate | [
"Chemistry"
] | 425 | [
"Ammonium compounds",
"Salts"
] |
5,549,120 | https://en.wikipedia.org/wiki/Lithium%20amide | Lithium amide or lithium azanide is an inorganic compound with the chemical formula . It is a white solid with a tetragonal crystal structure. Lithium amide can be made by treating lithium metal with liquid ammonia:
Lithium amide decomposes into ammonia and lithium imide upon heating.
Applications
Lithium amide, when mixed with lithium hydride, shows applications in hydrogen storage.The reaction begins with lithium amide's decomposition into ammonia and lithium imide. Lithium hydride then deprotonates ammonia to form lithium amide. The reverse reaction can occur between hydrogen and the lithium imide side product.
Other lithium amides
The conjugate bases of amines are known as amides. Thus, a lithium amide may also refer to any compound in the class of the lithium salt of an amine. These compounds have the general form , with the chemical lithium amide itself as the parent structure. Common lithium amides include lithium diisopropylamide (LDA), lithium tetramethylpiperidide (LiTMP), and lithium hexamethyldisilazide (LiHMDS). They are produced by the reaction of Li metal with the appropriate amine:
Lithium amides are very reactive compounds. Specifically, they are strong bases.
Examples
Lithium tetramethylpiperidide has been crystallised as a tetramer. On the other hand, the lithium derivative of bis(1-phenylethyl)amine crystallises as a trimer:
It is also possible to make mixed oligomers of metal alkoxides and amides. These are related to the superbases, which are mixtures of metal alkoxides and alkyls. The cyclic oligomers form when the nitrogen of the amide forms a sigma bond to a lithium, while the nitrogen lone pair binds to another metal centre.
Other organolithium compounds (such as BuLi) are generally considered to exist in and function via high-order, aggregated species.
See also
Sodium amide
Potassium amide
Butyllithium
Lithium imide
Lithium nitride
References
Merck Index, 11th Edition, 5398.
External links
Lithium salts
Metal amides | Lithium amide | [
"Chemistry"
] | 458 | [
"Metal amides",
"Coordination chemistry",
"Lithium salts",
"Salts"
] |
5,549,155 | https://en.wikipedia.org/wiki/Pictive | PICTIVE (Plastic Interface for Collaborative Technology Initiative through Video Exploration) is a participatory design method used to develop graphical user interfaces.
It was developed at Bellcore around 1990.
Usability
Human–computer interaction | Pictive | [
"Engineering"
] | 45 | [
"Human–computer interaction",
"Human–machine interaction"
] |
5,549,818 | https://en.wikipedia.org/wiki/Figure%20of%20merit | A figure of merit (FOM) is a performance metric that characterizes the performance of a device, system, or method, relative to its alternatives.
Examples
Accuracy of a rifle
Audio amplifier figures of merit such as gain or efficiency
Battery life of a laptop computer
Calories per serving
Clock rate of a CPU is often given as a figure of merit, but is of limited use in comparing between different architectures. FLOPS may be a better figure, though these too are not completely representative of the performance of a CPU.
Contrast ratio of an LCD
Frequency response of a speaker
Fill factor of a solar cell
Resolution of the image sensor in a digital camera
Measure of the detection performance of a sonar system, defined as the propagation loss for which a 50% detection probability is achieved
Noise figure of a radio receiver
The thermoelectric figure of merit, zT, a material constant proportional to the efficiency of a thermoelectric couple made with the material
The figure of merit of digital-to-analog converter, calculated as (power dissipation)/(2ENOB × effective bandwidth) [J/Hz]
Luminous efficacy of lighting
Profit of a company
Residual noise remaining after compensation in an aeromagnetic survey
Heat absorption and transfer quality for a solar cooker
Computational benchmarks are synthetic figures of merit that summarize the speed of algorithms or computers in performing various typical tasks.
References
Engineering ratios | Figure of merit | [
"Mathematics",
"Engineering"
] | 286 | [
"Quantity",
"Metrics",
"Engineering ratios"
] |
5,550,038 | https://en.wikipedia.org/wiki/Unlicensed%20Personal%20Communications%20Services | Unlicensed Personal Communications Services or UPCS band is the 1920–1930 MHz frequency band allocated by the United States Federal Communications Commission (FCC) for short range Personal Communications Services (PCS) applications in the United States, such as the Digital Enhanced Cordless Telecommunications (DECT) wireless protocol.
History
Prior to an FCC rules change in April 2005, the band also included the frequencies 1910-1920 MHz and 2390–2400 MHz. These were used for a variety of short range communications, including point-to-point microwave links.
Allocation
These allocation rules are described in Title 47, Part 15 of the Code of Federal Regulations.
Licensed PCS, although not necessarily distinguished as such from UPCS, is used for digital mobile phone services.
DECT devices designed to operate in this band in the US use the marketing term DECT 6.0.
See also
Amateur radio (Licence Required)
Citizens band radio
Family Radio Service
General Mobile Radio Service
Multi-Use Radio Service
Bandplans
Telephone services
Consumer electronics
Radio technology
Radio regulations | Unlicensed Personal Communications Services | [
"Technology",
"Engineering"
] | 206 | [
"Information and communications technology",
"Telecommunications engineering",
"Radio technology"
] |
5,550,192 | https://en.wikipedia.org/wiki/Carlos%20J.%20Finlay%20Prize%20for%20Microbiology | The Carlos J. Finlay Prize is a biennial scientific prize sponsored by the Government of Cuba and awarded since 1980 by the United Nations Educational, Scientific and Cultural Organization (UNESCO) to people or organizations for their outstanding contributions to microbiology (including immunology, molecular biology, genetics, etc.) and its applications. Winners receive a grant of $5,000 USD donated by the Government of Cuba and an Albert Einstein Silver Medal from UNESCO.
The Prize is awarded in odd years (to coincide with UNESCO's General Conference) and is named after Carlos Juan Finlay (1833 – 1915), a Cuban physician and microbiologist widely known for his pioneering discoveries in the field of yellow fever.
Winners
Source: UNESCO
1980 - Roger Y. Stanier (Canada)
1983 - César Milstein, FRS (Argentina, United Kingdom)
1985 - and Ruth Nussenzweig (Brazil)
1987 - Hélio Gelli Pereira (Brazil) and (Sweden)
1989 - Georges Cohen (France) and Walter Fiers (Belgium)
1991 - Margarita Salas and (Spain) and Jean-Marie Ghuysen (Belgium)
1993 - James Michael Lynch (UK), James Tiedje (USA), Johannes Antonie Van Veen (Netherlands)
1995 - Jan Balzarini (Belgium) and Pascale Cossart (France)
1996 - Etienne Pays (Belgium) and Sheikh Riazzudin (Pakistan)
1999 - (Hungary)
2001 - Susana López Charreton and Carlos Arias Ortiz (Mexico)
2003 - Antonio Peña Díaz (Mexico)
2005 - Khatijah Yusoff (Malaysia)
2015 - Yoshihiro Kawaoka (Japan)
2017 - Samir Kumar Saha (Bangladesh) and Shahida Hasnain (Pakistan)
2020 - Kenya Honda (Japan)
2023 - Dilfuza Egamberdieva (Uzbekistan)
See also
List of biology awards
References
Biology awards
UNESCO awards
Awards established in 1980 | Carlos J. Finlay Prize for Microbiology | [
"Technology"
] | 392 | [
"Science and technology awards",
"Biology awards"
] |
5,550,368 | https://en.wikipedia.org/wiki/Pixel%20aspect%20ratio | A Pixel aspect ratio (often abbreviated PAR) is a mathematical ratio that describes how the width of a pixel in a digital image compared to the height of that pixel.
Most digital imaging systems display an image as a grid of tiny, square pixels. However, some imaging systems, especially those that must be compatible with standard-definition television motion pictures, display an image as a grid of rectangular pixels, in which the pixel width and height are different. Pixel aspect ratio describes this difference.
Use of pixel aspect ratio mostly involves pictures pertaining to standard-definition television and some other exceptional cases. Most other imaging systems, including those that comply with SMPTE standards and practices, use square pixels.
PAR is also known as sample aspect ratio and abbreviated SAR, though it can be confused with storage aspect ratio.
Introduction
The ratio of the width to the height of an image is known as the aspect ratio, or more precisely the display aspect ratio (DAR) – the aspect ratio of the image as displayed; for TV, DAR was traditionally 4:3 (a.k.a. fullscreen), with 16:9 (a.k.a. widescreen) now the standard for HDTV. In digital images, there is a distinction with the storage aspect ratio (SAR), which is the ratio of pixel dimensions. If an image is displayed with square pixels, then these ratios agree; if not, then non-square, "rectangular" pixels are used, and these ratios disagree. The aspect ratio of the pixels themselves is known as the pixel aspect ratio (PAR) – for square pixels this is 1:1 – and these are related by the identity:
{| class="wikitable"
|-
| SAR × PAR = DAR
|}
Rearranging (solving for PAR) yields:
{| class="wikitable"
|-
| PAR = DAR / SAR
|}
For example:
A 640 × 480 VGA image has a SAR of 640/480 = 4:3, and if displayed on a 4:3 display (DAR = 4:3) has square pixels, hence a PAR of 1:1.
By contrast, a 720 × 576 D-1 PAL image has a SAR of 720/576 = 5:4, but if displayed on a 4:3 display (DAR = 4:3) the PAR is 4/3 : 5/4 = 16:15 ≈ 1.066. This means that the pixels of the PAL picture must be "stretched" by this amount to fit in the 4:3 display.
In analog images such as film there is no notion of pixel, nor notion of SAR or PAR, but in the digitization of analog images the resulting digital image has pixels, hence SAR (and accordingly PAR, if displayed at the same aspect ratio as the original).
Non-square pixels arise often in early digital TV standards, related to digitalization of analog TV signals – whose vertical and "effective" horizontal resolutions differ and are thus best described by non-square pixels – and also in some digital video cameras and computer display modes, such as Color Graphics Adapter (CGA). Today they arise also in transcoding between resolutions with different SARs.
Actual displays do not generally have non-square pixels, though digital sensors might; they are rather a mathematical abstraction used in resampling images to convert between resolutions.
There are several complicating factors in understanding PAR, particularly as it pertains to digitization of analog video:
First, analog video does not have pixels, but rather a raster scan, and thus has a well-defined vertical resolution (the lines of the raster), but not a well-defined horizontal resolution, since each line is an analog signal. However, by a standardized sampling rate, the effective horizontal resolution can be determined by the sampling theorem, as is done below.
Second, due to overscan, some of the lines at the top and bottom of the raster are not visible, as are some of the possible image on the left and right – see Overscan: Analog to digital resolution issues. Also, the resolution may be rounded (DV NTSC uses 480 lines, rather than the 486 that are possible).
Third, analog video signals are interlaced – each image (frame) is sent as two "fields", each with half the lines. Thus either the pixels are twice as tall as they would be without interlacing, or the image is deinterlaced.
Background
Video is presented as a sequential series of images called video frames. Historically, video frames were created and recorded in analog form. As digital display technology, digital broadcast technology, and digital video compression evolved separately, it resulted in video frame differences that must be addressed using pixel aspect ratio. Digital video frames are generally defined as a grid of pixels used to present each sequential image. The horizontal component is defined by pixels (or samples), and is known as a video line. The vertical component is defined by the number of lines, as in 480 lines.
Standard-definition television standards and practices were developed as broadcast technologies and intended for terrestrial broadcasting, and were therefore not designed for digital video presentation. Such standards define an image as an array of well-defined horizontal "Lines", well-defined vertical "Line Duration" and a well-defined picture center. However, there is not a standard-definition television standard that properly defines image edges or explicitly demands a certain number of picture elements per line. Furthermore, analog video systems such as NTSC 480i and PAL 576i, instead of employing progressively displayed frames, employ fields or interlaced half-frames displayed in an interwoven manner to reduce flicker and double the image rate for smoother motion.
Analog-to-digital conversion
As a result of computers becoming powerful enough to serve as video editing tools, video digital-to-analog converters and analog-to-digital converters were made to overcome this incompatibility. To convert analog video lines into a series of square pixels, the industry adopted a default sampling rate at which luma values were extracted into pixels. The luma sampling rate for 480i pictures was MHz and for 576i pictures was MHz.
The term pixel aspect ratio was first coined when ITU-R BT.601 (commonly known as Rec. 601) specified that standard-definition television pictures are made of lines of exactly 720 non-square pixels. ITU-R BT.601 did not define the exact pixel aspect ratio but did provide enough information to calculate the exact pixel aspect ratio based on industry practices: The standard luma sampling rate of precisely MHz. Based on this information:
The pixel aspect ratio for 480i would be 10:11 as:
The pixel aspect ratio for 576i would be 59:54 as:
SMPTE RP 187 further attempted to standardize the pixel aspect ratio values for 480i and 576i. It designated 177:160 for 480i or 1035:1132 for 576i. However, due to significant difference with practices in effect by industry and the computational load that they imposed upon the involved hardware, SMPTE RP 187 was simply ignored. SMPTE RP 187 information annex A.4 further suggested the use of 10:11 for 480i.
As of this writing, ITU-R BT.601-6, which is the latest edition of ITU-R BT.601, still implies that the pixel aspect ratios mentioned above are correct.
Digital video processing
As stated above, ITU-R BT.601 specified that standard-definition television pictures are made of lines of 720 non-square pixels, sampled with a precisely specified sampling rate. A simple mathematical calculation reveals that a 704 pixel width would be enough to contain a 480i or 576i standard 4:3 picture:
A 4:3 480-line picture, digitized with the Rec. 601-recommended sampling rate, would be 704 non-square pixels wide.
A 4:3 576-line picture, digitized with the Rec. 601-recommended sampling rate, would be non-square pixels wide.
Unfortunately, not all standard TV pictures are exactly 4:3: As mentioned earlier, in analog video, the center of a picture is well-defined but the edges of the picture are not standardized. As a result, some analog devices (mostly PAL devices but also some NTSC devices) generated motion pictures that were horizontally (slightly) wider. This also proportionately applies to anamorphic widescreen (16:9) pictures. Therefore, to maintain a safe margin of error, ITU-R BT.601 required sampling 16 more non-square pixels per line (8 more at each edge) to ensure saving all video data near the margins.
This requirement, however, had implications for PAL motion pictures. PAL pixel aspect ratios for standard (4:3) and anamorphic wide screen (16:9), respectively 59:54 and 118:81, were awkward for digital image processing, especially for mixing PAL and NTSC video clips. Therefore, video editing products chose the almost equivalent values, respectively 12:11 and 16:11, which were more elegant and could create PAL digital images at exactly 704 pixels wide, as illustrated:
For PAL 4:3:
For PAL 16:9:
Inconsistency in defined pixel aspect ratio values
Commonly found on the Internet and in various other published media are numerous sources that introduce different and highly incompatible values as the pixel aspect ratios of various video pictures and video systems. (See the Supplementary sources section.)
To neutrally judge the accuracy and/or feasibility of these sources, please note that as the digital motion picture was invented years after the traditional motion picture, all video pictures targeted for standard definition television and compatible media, digital or otherwise, have (and must have) specifications compatible with standard definition television. Therefore, the pixel aspect ratio of digital video must be calculated from the specification of common traditional equipment rather than the specifications of digital video. Otherwise, any pixel aspect ratio that is calculated from a digital video source is only usable in certain cases for the same kind of video sources and cannot be considered/used as a general pixel aspect ratio of any standard definition television system.
In addition, unlike digital video that has well-defined picture edges, traditional video systems have never standardized a well-defined edge for the picture. Therefore, the pixel aspect ratio of common standard television systems cannot be calculated based on edges of pictures. Such a calculated aspect ratio value would not be entirely wrong, but also cannot be considered as the general pixel aspect ratio of any specific video system. The use of such values would be restricted only to certain cases.
Modern standards and practices
In modern digital imaging systems and high-definition televisions, especially those that comply with SMPTE standards and practices, only square pixels are used for broadcast and display. However, some formats (ex., HDV, DVCPRO HD) use non-square pixels internally for image storage, as a way to reduce the amount of data that must be processed, thus limiting the necessary transfer rates and maintaining compatibility with existing interfaces.
Issues of non-square pixels
Directly mapping an image with a certain pixel aspect ratio on a device whose pixel aspect ratio is different makes the image look unnaturally stretched or squashed in either the horizontal or vertical direction. For example, a circle generated for a computer display with square pixels looks like a vertical ellipse on a standard-definition NTSC television that uses vertically rectangular pixels. This issue is more evident on wide-screen TVs.
Pixel aspect ratio must be taken into consideration by video editing software products that edit video files with non-square pixels, especially when mixing video clips with different pixel aspect ratios. This would be the case when creating a video montage from various cameras employing different video standards (a relatively rare situation). Special effects software products must also take the pixel aspect ratio into consideration, since some special effects require calculation of the distances from a certain point so that they look visually correct. An example of such effects would be radial blur, motion blur, or even a simple image rotation.
Use of pixel aspect ratio
Pixel aspect ratio value is used mainly in digital video software, where motion pictures must be converted or reconditioned to use video systems other than the original. The video player software may use pixel aspect ratio to properly render digital video on screen. Video editing software uses pixel aspect ratio to properly scale and render a video into a new format.
The pixel aspect ratio support is also required to display, without distortion, legacy digital images from computer standards and video-games what existed in the 80s. In that generation, square pixels were too expensive to produce, so machines and video cards like the SNES, CGA, EGA, Hercules, C64, MSX, PC-88, X68000 etc had non-square pixels.
Confusion with display aspect ratio
Pixel aspect ratio is often confused with different types of image aspect ratios; the ratio of the image width and height. Due to non-squareness of pixels in Standard-definition TV, there are two types of such aspect ratios: storage aspect ratio (SAR) and display aspect ratio (abbreviated DAR, also known as image aspect ratio and picture aspect ratio). Also, pixel aspect ratio (PAR) is also known as sample aspect ratio (abbreviated SAR) in some industrial standards (such as H.264) and output of programs (such as ffmpeg). Note the reuse of the abbreviations PAR and SAR. This article uses only the terms pixel aspect ratio, display aspect ratio and storage aspect ratio to avoid ambiguity.
Storage aspect ratio is the ratio of the image width to height in pixels, and can be easily calculated from the video file. Display aspect ratio is the ratio of image width to height (in a unit of length such as centimeters or inches) when displayed on screen, and is calculated from the combination of pixel aspect ratio and storage aspect ratio.
However, users who know the definition of these concepts may get confused as well. Poorly crafted user-interfaces or poorly written documentations can easily cause such confusion: Some video-editing software applications often ask users to specify an "aspect ratio" for their video file, presenting him or her with the choices of "4:3" and "16:9". Sometimes, these choices may be "PAL 4:3", "NTSC 4:3", "PAL 16:9" and "NTSC 16:9". In such situations, the video editing program is implicitly asking for the pixel aspect ratio of the video file by asking for information about the video system from which the video file originated. The program then uses a table (similar to the one below) to determine the correct pixel aspect ratio value.
Generally speaking, to avoid confusion, it can be assumed that video editing products never ask for the storage aspect ratio as they can directly retrieve or calculate it. Non-square-pixel–aware applications also need only to ask for either pixel aspect ratio or display aspect ratio, from either of which they can calculate the other.
Pixel aspect ratios of common video formats
Pixel aspect ratio values for common standard-definition video formats are listed below. Note that for PAL video formats, two different types of pixel aspect ratio values are listed:
Rec.601, a Rec.601-compliant value, which is considered the real pixel aspect ratio of standard-definition video of that type.
Digital, which is roughly equivalent to Rec.601 and is more suitable to use in Digital Video Editing software.
Note that sources differ on PARs for common formats – for example, 576 lines (PAL) displayed at 4:3 (DAR) corresponds to either PAR of 12:11 (if 704×576, SAR = 11:9), or a PAR of 16:15 (if 720×576, SAR = 5:4). See references for sources giving both, and SDTV: Resolution for a table of storage, display and pixel aspect ratios. Also note that CRT televisions do not have pixels, but scanlines.
References
Main sources
As of the retrieval date, a free membership of ITU Online Bookstore would allow free download of up to three ITU-R Recommendations.
This standard, which is the basis for HDMI, specifies 16:15 (1.0666) as the pixel aspect ratio of 4:3 576i/p and 8:9 (0.888) as the pixel aspect ratio of 4:3 480i/p.
Supplementary sources
A PDF version of Adobe Premiere Pro CS4 Documentations is also available from Adobe web site.
This source specifies 12:11 (1.09) as the pixel aspect ratio of 576i.
A PDF version of Adobe After Effects CS4 Documentations is also available from Adobe web site.
This source specifies 12:11 (1.09) as the pixel aspect ratio of 576i.
This source calculates different pixel aspect ratio values for 480i and 576i pictures.
An in depth analysis on the discrepancies of the pixel aspect ratios provided in various specifications.
Creative Commons Attribution, Noncommercial-Share Alike 3.0 Germany (CC by-sa)
English translation:
Notes
External links
The Pixel Aspect Ratio Acid Test
Engineering ratios
Digital television
Film and video technology
Computer graphics data structures
Image processing
Digital geometry
Digital imaging | Pixel aspect ratio | [
"Mathematics",
"Engineering"
] | 3,550 | [
"Quantity",
"Metrics",
"Engineering ratios"
] |
5,550,378 | https://en.wikipedia.org/wiki/Time%20between%20overhauls | Time between overhauls (abbreviated as TBO or TBOH) is the manufacturer's recommended number of running hours or calendar time before an aircraft engine or other component requires overhaul.
On rotorcraft, many components have recommended or mandatory TBOs, including main rotor blades, tail rotor blades and gearboxes.
For engines, the time between overhauls is generally a function of the complexity of the engine and how it is used. Piston-based engines are much more complex than turbine-powered engines, and generally have TBOs on the order of 1,200 to 2,000 hours of running time. They tend toward the lower number if they are new designs, or include boosting options such as a turbocharger. In comparison, jet engines and turboprops have TBOs from 3,000 hours up to 16,000 hours or more.
Since overhauling requires that the engine be disassembled, parts inspected and measured, and many parts replaced, it is typically a labour-intensive and hence expensive operation. The value of a used engine decreases as hours increase since its last overhaul, so sellers of used engines (and aircraft) typically list the engine's time since major overhaul (SMOH) when advertising the engine (or the aircraft it is fitted in) for sale.
The TBO is a time "recommended" by the manufacturer, and depending upon what rules the aircraft operates under, overhauling the engine at this time is not necessarily mandatory. Depending on the country of registration, aircraft in non-commercial use overhauls may not be mandatory; overhauls at the scheduled times are nevertheless highly recommended for reliability and safety. Likewise, overhaul at the TBO does not guarantee that the engine will last that long.
References
External links
What Makes an Engine Airworthy? AOPA
Aircraft engines
Aircraft maintenance | Time between overhauls | [
"Technology",
"Engineering"
] | 365 | [
"Aircraft maintenance",
"Aerospace engineering",
"Engines",
"Aircraft engines"
] |
5,550,711 | https://en.wikipedia.org/wiki/Ark%20Two%20Shelter | The Ark Two Shelter is a nuclear fallout shelter built by Bruce Beach (14 April 1934 – 10 May 2021) in the village of Horning's Mills (north of Toronto, Ontario). The shelter first became habitable in 1980 and has been continuously expanded and improved since then. The shelter is composed of 42 school buses, which were buried underground as patterns for concrete that was then poured over to provide the main structure, onto which up to 5 meters (14 feet) of earth were piled to provide fallout protection.
With construction beginning in the early 1980s (during the Cold War), the shelter was designed to accommodate as many as five hundred people for the length of time required to allow the widespread nuclear fallout to decay to a level allowing a safe return to the surface after a cataclysmic nuclear event.
Powered by redundant diesel generators, the heavily fortified ("virtually impenetrable to anything short of a direct nuclear strike") shelter includes two commercial kitchens, full plumbing (including a private well for potable water and a motel-sized septic tank), three months' worth of diesel, a radio-based communications centre, a chapel, and a decontamination room.
Ark Two is equipped with a communications room capable of broadcasting locally on the FM broadcast band and throughout Canada and the United States on the AM and Shortwave bands. A particularly novel feature is a collapsible, weather-balloon-deployed antenna, capable of being launched from within the shelter. All Ark Two communication equipment is EMP-hardened and generator-powered so as to be able to transmit survival information to the general public in the event of nuclear war.
Beach did not charge money for admission to the shelter, instead guaranteeing individuals admission in return for sweat equity and active involvement in the Ark Two communities' various activities. In addition, "Everyone is welcome here, regardless of religion, race, nationality, political views..." In return for the promise of safe haven in times of nuclear attack, a person residing in nearby areas might be expected to, for example, work at the shelter several weekends each year, assisting in the routine maintenance or continuing renovations of the facility. A large percentage of the shelter population is expected to be children, as the primary purpose of the shelter is to serve as an "underground orphanage, a place where a new generation could be saved from nuclear apocalypse," which, according to Beach, would otherwise wipe out over 80% of the world's population. "We're going to say to people: 'Well, we have room for your children, but we don't have room for you.' That's the nature of life... this is the lifeboat."
Beach believed that the majority of preppers are too concerned with personal survival, when they should be focused on reconstructing the world after a cataclysmic disaster. He ran an online "reconstruction network" (the "SAFE" community) through which he shared information about Ark Two and his evacuation plans.
Ark Two was featured in Beach's interview for National Geographic's Doomsday Preppers, episode 8: "It's Gonna Get Worse". It was also featured on the Global Television Network series 16:9, and on the Showtime series Penn & Teller: Bullshit! episode "End of the World" and How the World Ends - "Nostradamus".
Beach died on May 10, 2021, of a heart attack.
Beach has authored two related books: Society After Doomsday and TRIAD Individual Networking: Preparedness For Disastrous Times.
See also
Nuclear War Survival Skills
Emergency Government Headquarters
References
External links
Official website of the shelter and the Ark Two Community
Buildings and structures in Dufferin County
Survivalism
Radiation protection
Nuclear fallout
Subterranea (geography) | Ark Two Shelter | [
"Chemistry",
"Technology"
] | 770 | [
"Nuclear fallout",
"Environmental impact of nuclear power",
"Radioactive contamination"
] |
5,550,798 | https://en.wikipedia.org/wiki/IOE%20engine | The intake/inlet over exhaust, or "IOE" engine, known in the US as F-head, is a four-stroke internal combustion engine whose valvetrain comprises OHV inlet valves within the cylinder head and exhaust side-valves within the engine block.
IOE engines were widely used in early motorcycles, initially with the inlet valve being operated by engine suction instead of a cam-activated valvetrain. When the suction-operated inlet valves reached their limits as engine speeds increased, the manufacturers modified the designs by adding a mechanical valvetrain for the inlet valve. A few automobile manufacturers, including Willys, Rolls-Royce and Humber also made IOE engines for both cars and military vehicles. Rover manufactured inline four and six cylinder engines with a particularly efficient version of the IOE induction system.
A few designs with the reverse system, exhaust over inlet (EOI), have been manufactured, such as the Ford Quadricycle of 1896.
Description
In a F-head/IOE engine, the intake manifold and its valves are located in the cylinder head above the cylinders, and are operated by rocker arms which reverse the motion of the pushrods so that the intake valves open downward into the combustion chamber. The exhaust manifold and its valves are located beside or as part of the cylinders, in the block. The exhaust valves are either roughly or exactly parallel with the pistons; their faces point upwards and they are not operated by separate pushrods, but by contact with a camshaft through the tappet or valve lifter and an integrated valve stem/pushrod. The valves were offset to one side, forming what seemed to be a pocket, leading to the term "pocket valve" being used for IOE engines. An F-head engine combines features from both overhead-valve and flathead type engines, the inlet valve operating via pushrod and rocker arm and opening downward like an overhead valve engine, while the exhaust valve is offset from the cylinder and opens upward via an integrated pushrod/valve stem directly actuated by the camshaft, much like the valves in a flathead engine.
Origin
The earliest IOE layouts used atmospheric inlet valves which were held closed with a weak spring and were opened by the pressure differential created when the piston went down on the inlet stroke. This worked well with low-speed early engines and had the benefit of being very simple and cheap, but the weak spring was unable to close the valve fast enough as engine speed increased. This required stronger springs, which in turn required direct mechanical action to open, as the atmospheric pressure of 15 PSI limits the total force available from creating a pressure differential, meaning that a spring is theoretical limit while for practical purposes, lighter springs were typically used. When the limits of this system were reached, the design was improved without substantial changes to the head casting by adding a mechanical system to open the inlet valves and stronger springs to close them. In both cases, the exhaust valves were in the block and were opened by contact with a camshaft through a tappet or valve lifter and closed by springs.
Advantages and disadvantages
The IOE design allows the use of larger valves than a sidevalve (or L-head) or overhead valve engine. Its advantages over the sidevalve/flathead also include a compact combustion chamber, a well-located spark plug, and a cooling effect from the mixture swirl, along with better intake mixture flow. Disadvantages include a combustion chamber of more complex shape than that of an overhead valve engine, which affects combustion rates and can create hot spots in the piston head, and inferior valve location, which hinders efficient scavenging. Due to the added complications of rocker arms and pushrods, it is also more complex and expensive to make than a sidevalve engine, as well as being physically larger due to the rocker arms being placed over the cylinder head, and it requires an inlet valve and ports in the cylinder head, while the cylinder of a sidevalve engine is simply a closed-end cylinder.
Rover IOE engines
Rover used a more advanced form of IOE engine. It was designed by Jack Swaine in the mid-late 1940s and was in production from 1948 to the early 1990s. Unlike the conventional F-head IOE, this had an efficient combustion chamber designed for good combustion, rather than simple manufacture. The top surface of the block was machined at an angle, with the piston crowns angled in a "pitched roof" to match. At TDC, the piston almost touched the angled inlet valve and provided good 'squish' to the combustion chamber itself, offset to the side by half a cylinder diameter. The resultant combustion chamber shape was a near-ideal hemisphere, although inverted and tilted from the usual "hemi-head" design. The spark plug was centrally mounted and this, together with the turbulence generated by the squish, provided a short flame path. The thinness of the gas layer between piston and inlet valve was so confined as to reduce the risk of detonation on poor fuel, one factor that kept it in service with Land Rover for so long. During the late 1940s and early 1950s when the only petrol available was low octane 'pool' petrol it also allowed Rover to run higher compression ratios than many competitors with the more usual side- or overhead valve designs.
The unusual combustion chamber arrangement with its angled valves also led to an unusual valve train. The block-mounted camshaft operates small wedge shaped rockers, one for each valve. In early models the camshaft acts on a simple pad on the rocker, but for later models this pad was replaced by a roller follower. The exhaust rockers act directly on the valves, whilst the inlet rockers act on pushrods running up to a second set of longer flat rockers operating the inlet valves. The Rover engine, like many 1940s and earlier British designs, was a small bore, long stroke (undersquare) engine to keep the RAC tax horsepower rating as low as possible, thus keeping the road tax as low as possible. The IOE layout enabled Rover to use larger valves than would normally be possible in a small bore engine, allowing better breathing and better performance.
The Rover IOE engine family encompassed straight-4 (1.6- and 2.0-litres) and straight-6 (2.1-, 2.2-, 2.3-, 2.4-, 2.6- and 3.0-litres) engines and powered much of the company's post-war range in the form of the P3, P4 and P5 models. Adapted versions of the 1.6 and 2.0 IOE engines were used in early version of the Land Rover as well. Power outputs ranged from 50bhp (Land Rover 1.6) to 134bhp (P5 3 litre MkII & III). The 2.6 6-cylinder IOE engine had a particularly long career. After being used in Rover P4 saloon cars it was added to long-wheelbase Land Rover models from 1963 in the 2A Forward Control models, then in 1967 in the bonneted 109", and remained an optional fitment until 1980 when it was replaced by the Rover V8.
Similar Packard cylinder head
The shape of the combustion chamber as an "inverted hemi-head", along with the angled cylinder head joint and pitched-roof piston crowns, had earlier been used in the 1930 Van Ranst-designed Packard V12 engine, although in this case the valves were both in the block as side valves and the spark plug was poorly placed at the extremity of the combustion chamber.
Other users
Motorcycles
The IOE valvetrain layout was used extensively in early American motorcycles, mainly based on a French design by De Dion-Bouton. Harley-Davidson used IOE engines with atmospheric inlet valves until 1912, and with mechanically driven inlet valves from 1911 to 1929. Indian used IOE valvetrains on all of their four-cylinder bikes except those built in 1936 and 1937. Other American motorcycle manufacturers that used IOE engines included Excelsior, Henderson, and Ace.
Automobiles
Hudson used an IOE inline-four engine in its Essex line of cars from 1919 to 1923 and an IOE straight-six engine in its Hudson line of cars from 1927 to 1929.
In Europe in the same period Humber Limited of Coventry, England produced a full range of cars using IOE engines, these were however phased out at the end of the 1920s in favour of models using cheaper L head engines shared with Hillman
Post WW2 Willys, and its successor Kaiser-Jeep, used variants of the Willys Hurricane engine from 1950 to 1971.
Rolls-Royce used an IOE straight-six engine originally designed immediately prior to WW2 in their post-war Silver Wraith. From this engine Rolls-Royce derived the B series engines for British Army combat vehicles which were produced in four, six and eight cylinder versions(the B40, B60 and B80) by Rolls-Royce (and in the case of the B40 used in the Austin Champ by Morris Motors)for military vehicles, fire appliances and even buses. A more advanced shorter stroke passenger car development the FB60 engine, a straight-six IOE engine displacing 3909cc and producing a claimed 175 , was used by BMC in the Vanden Plas Princess 4-litre R saloon car. Over 6000 of these cars were made.
Exhaust over intake (EOI)
Some engines have been made with the reverse configuration, having the exhaust valve located in the cylinder head and the intake valve in the block. The ABC Skootamota began production with an engine of this configuration, but this was changed to an overhead valve engine before production ended.
In 1936 and 1937, the Indian Four had the valve positions reversed, with the exhaust valve in the head and the inlet valve in the block. In theory, this would improve fuel vaporization, and the engine was actually more powerful. However, the new system made the cylinder head very hot. The exhaust valve linkage required frequent adjustment. The design returned to the original IOE configuration in 1938.
See also
Harley-Davidson engine timeline
References
Cam-in-block valvetrain configurations
Cylinder head
Engine technology
Engine valvetrain configurations
Harley-Davidson engines
Motorcycle engines
Piston engines
Piston engine configurations | IOE engine | [
"Technology"
] | 2,096 | [
"Engine technology",
"Piston engines",
"Motorcycle engines",
"Engines"
] |
5,551,009 | https://en.wikipedia.org/wiki/NEMA%20connector | NEMA connectors are power plugs and sockets used for AC mains electricity in North America and other countries that use the standards set by the US National Electrical Manufacturers Association. NEMA wiring devices are made in current ratings from 15 to 60 amperes (A), with voltage ratings from 125 to 600 volts (V). Different combinations of contact blade widths, shapes, orientations, and dimensions create non-interchangeable connectors that are unique for each combination of voltage, electric current carrying capacity, and grounding system.
NEMA 1-15P (two-pole, no ground) and NEMA 5-15P (two-pole with ground pin) plugs are used on common domestic electrical equipment, and NEMA 5-15R is the standard 15-ampere electric receptacle (outlet) found in the United States, and under relevant national standards, in Canada (CSA C22.2 No. 42), Mexico (NMX-J-163-ANCE) and Japan (JIS C 8303).
Other plug and receptacle types are for special purposes or for heavy-duty applications.
The dimensional standard for electrical connectors is ANSI/NEMA WD-6 and is available from the NEMA website.
Precedents
In the early days of electrification, residential use was almost exclusively for illumination, with rooms normally having just a single electrical outlet spot in the center. Along with his lightbulb, Thomas Edison developed the Edison screw in the early 1880s, patented 1881. The Edison screw was very successful, and quickly became the first de facto standard for electric connection. In the early 1900s, table and floor lamps became more popular, and sockets were mounted on walls for secondary connections. One big disadvantage of screw connectors was that the cord inevitably got twisted after being connected to the receptacle.
Harvey Hubbell's inventions
In 1903, Harvey Hubbell filled the , for a lightbulb socket adaptor and plug, also a standalone receptacle. The adaptor was screwed into the lightbulb socket, leaving a flat face with two holes to conveniently attach the plug. The same patent had a second design, with a wall attachable receptacle, capable of receiving the same plug, thus being the first socket and plug design patented in the US. Later in 1904, he changed the design to flat blades (a design later incorporated in the NEMA 2 series), filled under the Both these patents were granted in .
In 1910, Hubbel worked on improving his popular flat blade design, filled in 1912. The new design had parallel blades, a more compact design and was easier to manufacture. This design was improved once again in 1915, introducing a polarized plug under the . The flat blade plug which in subsequent years evolved to become NEMA 1-15 was born.
Other American manufacturers
In addition to Hubbell's system, a large variety of different plugs and receptacles circulated, some of them compatible with Hubbell's, some not. In 1919, Hubbell unsuccessfully tried to prevent other manufacturers from making receptacles and plugs to the dimensions used by Hubbell. The report of the court proceedings includes a comprehensive review of the development of the art in the US prior to 1919, based on evidence presented to the court. Separable plugs had been available for more than a decade prior to Hubbell's 1904 design.
NEMA
In 1926, the National Electrical Manufacturers Association (NEMA) was founded by the merger of the Electric Power Club and the Associated Manufacturers of Electrical Supplies and represented manufacturing companies of the electrical segment in a national level. NEMA provided a forum between companies for reaching standardization, but it was not until the 1940s that NEMA started to publish standards on receptacles and plugs, much later than UK, France and Germany. Since NEMA was a forum between manufacturers and not an governmental body, any decision had to be thoroughly discussed and agreed upon by its members, which substantially slowed the standardization process.
Nomenclature
NEMA connectors are named following an alphanumeric code consisting of: (prefix L for locking) numerals – numerals (suffix R for receptacle, P for plug).There are two basic classifications of NEMA connectors: straight-blade and locking. The metal conductive blades are often informally called prongs (as in 3-prong plug). Numbers prefixed by 'L' are curved-blade, twist-locking connectors. Twist-locking types are used for heavy industrial and commercial equipment, where increased protection against accidental disconnection is required.
The numerals preceding the hyphen encode the number of poles (current-carrying terminals) and wires connected to it, the voltage, and single- or three-phase power. A connector with ground terminal has more wires than poles: two-pole, three-wire; or four-pole, five-wire; etc. A non-grounded device may be two-pole, two-wire; three-pole, three-wire; etc.
The numerals following the hyphen is the current rating of the device in amperes. This number is followed by the letter 'R' to indicate a receptacle (socket) or 'P' to indicate a plug (prongs).
As an example, the 5-15R is the common 125 V two-pole, three-wire receptacle rated for 15 A. The L5-15R, while sharing the same electrical rating, is a locking design that is not physically compatible with the straight-blade 5-15 design. The 5-30R has the same two-pole, three-wire configuration and 125 V rating, but is rated for 30 A.
Although there are several non-grounding device types in the NEMA standards, only three of them are in widespread use today. These are the two-pole 1-15, still in use in millions of buildings built before the 1960s, and the three-pole 10-30 and 10-50.
Other types of NEMA connectors that do not follow this nomenclature include: the ML series (so-called "Midget Locking" connectors named for their diminutive size), TT (for connecting travel trailers and other recreational vehicles to external power sources), SS series ("ship-to-shore" connectors for connecting boats to shore power) and the FSL series (used in military and aircraft applications).
The small hole near the end of the power (non-ground) blades of some NEMA plugs is used for convenience in manufacturing; if present, it must be of specified diameter and position. Small specialized padlocks are available to fit these holes, allowing "lockout" of hazardous equipment, by physically preventing insertion of locked plugs into a power receptacle. Since at least 1949, numerous receptacle devices have also been invented to use these holes to hold the prongs inside the receptacle slots, using a corresponding latch or locking mechanism.
The blades of a NEMA connector are identified within the dimensional standard as follows: 'G' identifies the grounding conductor, 'W' identifies the (grounded) neutral conductor, and 'X', 'Y', and 'Z' are the "hot" line conductors. Single-phase connectors have only a single terminal identified as 'X' or two terminals, 'X' and 'Y'. Three-phase connectors will use 'X', 'Y' and 'Z'.
Criticism has been aimed at the design leaving a gap with exposed prongs. This safety flaw has been exploited by a January 2020 Internet phenomenon known as the Outlet challenge, where conductive materials, usually coins or paper clips were dropped into the gap, causing electric sparks, which once led to a building evacuation in Westford Academy.
Non-locking connectors
NEMA non-locking connectors all use blades of various flat and folded shapes (except for the round pins used on grounding connectors). The plugs can be detached from the receptacles by pulling back on the plug body. These connector families have been designed so that connectors of differing types cannot be accidentally intermated.
NEMA wall receptacles can be found installed in any orientation. Neither NEMA nor the US National Electrical Code nor the Canadian Electrical Code specify a preferred orientation, but the National Electrical Contractors Association's National Electrical Installation Standards (NECA 130-2010) specify that the preferred location of the ground is on top. When the ground blade of a receptacle is on the bottom, the neutral blade is on the upper left and the hot blade is on the upper right. All descriptions below assume this orientation (i.e., clockwise order is ground, neutral, hot for 120 V receptacle versions; and counter-clockwise for plug versions).
NEMA 1
This "2-prong" design, with two flat parallel non-coplanar blades and slots, is used in most of North America and on the east coast of South America on lamps; consumer electronics such as clocks, radios, and battery chargers; and other double-insulated small appliances that do not require grounding (earthing).
All NEMA 1 devices are two-wire non-grounding devices (hot-neutral) rated for 125 V maximum. 1-15P plugs have two parallel flat blades, wide, thick, long, and spaced apart.
1-15R receptacles have been prohibited in new construction in the United States and Canada since 1962, but remain in many older buildings, and this obsolete design is still available for repair use only. Since January 1, 1974, all new power outlets are required to have a ground connection, using grounded receptacles (typically 5-15R or 5-20R) that accept both grounded and non-grounded plugs.
Replacement of obsolete NEMA 1 receptacles requires either rewiring with an additional ground conductor for a NEMA 5 receptacle, or a NEMA 5 receptacle complete with a ground fault circuit interrupter for two-wire non-grounded configurations (when a ground conductor is not available).
Ungrounded NEMA 1 plugs are still popularly used by manufacturers of small appliances and electronic devices because of the design's low cost and compact size, and they are upward compatible with modern grounded NEMA 5 receptacles. Standards permit ungrounded plugs where the appliance does not require grounding due to low risk of leakage current, such as on double-insulated devices.
In older plug designs both blades were the same width, so the plug could be inserted into the receptacle either way around. Many plugs manufactured since 1948 are polarized; the neutral blade is wide, wider than the line blade, so the plug can be inserted only one way. Polarized 1-15P plugs will not fit into unpolarized receptacles, which possess only narrow slots. Polarized 1-15P plugs will fit 5-15R grounded receptacles, which have the same wider slot for the neutral blade. Some devices that do not distinguish between neutral and line, such as internally isolated AC adapters, are still produced with unpolarized narrow blades. Cheater plug adapters allow a "3-prong" grounded 5-15P plug to be mated to a non-grounded 1-15R receptacle. The adapters include a spade lug to allow connecting to ground, often via the cover screw used to attach the outlet faceplate. These adapters are illegal in some jurisdictions, in particular throughout Canada.
There are some obsolete 1-15R or 1-20R (120 V, 15 or 20 A) receptacles which are mechanically able to accept 1-15P (120 V), 1-20P (120 V), 2-15P (240 V), or 2-20P (240 V) plugs. These receptacles are typically found in older residential buildings and are not allowed to be installed under current NEC codes. In addition to the lack of grounding, these obsolete receptacles could allow a connected device to overheat and create a fire hazard if a device designed for the wrong voltage is connected. These problematic outlets are easily identifiable due to their lack of ground, along with both openings on the receptacle face being a sideways T-shaped opening that appear to be mirrored on the vertical center line of the face. Due to the potential danger of a voltage mismatch, whenever possible these receptacles should be replaced. Depending on local code, replacement with a "repair" approved non-grounded receptacle may be sufficient.
The Japanese plug and socket with narrow insulating faces appear and work physically identical to NEMA 1-15, and such non-grounded receptacles are still common in Japan (though grounded 5-15R and 5-20R receptacles are slowly becoming more common). The Japanese system incorporates stricter dimensional requirements for the plug housing, different marking requirements, and mandatory testing and approval by METI or JIS.
NEMA standards exist for 1-15P, 1-20P and 1-30P plugs, and the 1-15R receptacle. There are no 1-20R and 1-30R receptacles, because 1-20P and 1-30P can mate with a corresponding NEMA 5 receptacle.
NEMA 2
All NEMA 2 devices are two-wire non-grounding devices (hot-hot) rated for 250 V maximum. Although standards exist for 2-15, 2-20 and 2-30, this series is obsolete, and only Hubbell still manufactures 2-20 devices (for repair purposes).
NEMA 3
This series of devices is specified for 277-volt, two-wire, non-grounding devices. According to NEMA, this is "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.
NEMA 4
This series of devices is specified for 600-volt, two-wire, non-grounding devices. Identically to the NEMA 3 series, this is "reserved for future configurations" and no designs for this series exist and no devices have been manufactured.
NEMA 5
All NEMA 5 devices are three-wire grounding devices (hot–neutral–ground) rated for 125 V maximum, with the 5-15, 5-20 and 5-30 being grounded versions of the 1-15, 1-20 and 1-30, respectively. The addition is a diameter round or U-shaped ground pin, longer than the power blades (so the device is grounded before the power is connected) and located from them by edge-to-edge or center-to-center.
Compared to the 5-15P plug, the 5-20P plug has the neutral blade rotated 90° and shifted so its inner edge is approximately from the hot blade. The 5-20R receptacle has a T-shaped neutral hole, to accept both 5-15P and 5-20P plugs. An acceptable alternative version of the 5-20R receptacle has a rectangular slot that will only accept 5-20P plugs. The 5-30 and 5-50 are physically larger, with between power pins; 5-30 also has an L-shaped neutral blade. These larger sizes are uncommon, as twist-locking plugs are generally used for high-current applications.
The neutral blade on 5-15P plugs is not always wider than the line blade, since the ground pin enforces polarity.
The Electrical Safety Foundation International has stated: "Never remove the ground pin (the third prong) to make a three-prong plug fit a two-prong outlet". In addition to the dangers of breaking a ground connection, removing the ground pin to make it fit a 1-15R receptacle or extension cord, may result in the live–neutral polarity being lost.
The 5-15R and 5-20R are by far the most common electrical receptacle in North America in buildings built since the mid-twentieth century. It is usually installed in a duplex configuration; two receptacles may share a common circuit or may each be wired separately, sometimes to a switch.
In 46 of the 50 United States and all of Canada, tamper-resistant receptacles are required in new residential construction . These prevent contact by objects like keys or paper clips inserted into the socket. This is accomplished by an interlocking mechanism that requires hot and neutral blades inserted simultaneously to release the small doors blocking the slots. The grounding slot is not blocked by a door.
In stage lighting for film and theater, this connector is sometimes informally known as PBG (Parallel Blade with Ground), U-ground, Edison or Hubbell, the name of a common manufacturer. (The name "Hubbell" can be confusing as several different connectors share this name depending on the company, industry, and use.) In the motion picture and TV production industries, an extension cord that uses this type of connector (usually with 12 AWG or 10 AWG wire) is called a "stinger". Generally, lighting technicians use these extension cords to deliver power to lights rated at 2,000 watts or less.
Internationally, the NEMA 5-15P plug and NEMA 5-15R receptacle are the basis for the International Electrotechnical Commission's IEC 60906-2 standard IEC system of plugs and sockets-outlets for household and similar purposesPart 2: Plugs and socket-outlets 15 A 125 V a.c. and 20 A 125 V a.c.
NEMA 6
All NEMA 6 devices are three-wire grounding devices (hot-hot-ground) used for 208 and 240 V circuits and rated for 250 V maximum, with the 6-15, 6-20 and 6-30 being grounding versions of the 2-15, 2-20 and 2-30, respectively. The 6-15 resembles the 5-15, but with collinear horizontal pins, spaced center-to-center. The 20 A plug has a blade rotated 90° (opposite blade from what would be the "line" blade on a 2-15 or 5-15 plug. This prevents accidental insertion of plugs into outlets that use different voltages), and the 6-20R receptacle has a T-shaped hole to accept both 6-15P and 6-20P plugs (similar to the 5-20R receptacle accepting 5-15P and 5-20P plugs). The 50 A (and 5-50) receptacles look like bigger versions of the 5-15 A. 6-15R and 6-20R receptacles are usually manufactured on the same assembly line as "Industrial" or "Commercial" grade 5-15R and 5-20R receptacles, with all 4 receptacles sharing the same "triple wipe" T contacts behind the varying faceplates. The faceplate bonded onto the receptacle determines the final configuration of the receptacle.
NEMA 6 devices, while specified as 250 V, may be used for either 208 or 240 V circuits, generally depending on whether the building has a three-phase or split-phase power supply, respectively. The NEMA 6-20R or 6-30R found in many hotel and motel rooms is typically supplied with either split-phase or two phases of three-phase 208 V.
The higher-current receptacles are rare, with twist-locking plugs such as L6-30 and direct wiring being more common. Generally, 6-series non-locking plugs are used for such appliances as large room air conditioners and commercial kitchen equipment; the occasional home arc welder also uses 6-50. Single-phase 6-50 is commonly used on farms for silo unloaders, and is used with a 6-gauge flexible power cord up to long. The 6-50 receptacle charges electric vehicles at the same 32- or 40-ampere maximum from charging stations, on a short cord, as the more versatile 14-50 with its fourth prong neutral not used currently for any electric vehicle charging purposes.
NEMA 7
NEMA 7 devices are three wire/prong (hot-neutral-ground) connectors rated at 277 V. The 15 A 7-15 plug has the crowsfoot current carrying pins of the Type I plug, but with a U-shaped earth pin. The 7-20 version has an enlarged line/hot pin. 7-30 is a larger diameter connector, with an L-shaped neutral, while the 7-50 has an enlarged neutral pin, compared with the hot.
NEMA 8
NEMA 8 devices are specified for three wire, two-pole, grounding devices for 480 volts. According to NEMA, this is "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.
NEMA 9
NEMA 9 devices are specified for three wire, two-pole, grounding devices for 600 volts. According to NEMA, this is "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.
NEMA 10
NEMA 10 connectors are a now deprecated type that had formerly been popular in the United States for use with high-power electric clothes dryers, kitchen ranges, and other high-power equipment. NEMA 14-30R and -50R connectors have generally replaced NEMA 10 equipment for these applications. NEMA 10s are classified as 125/250 V non-grounding (hot-hot-neutral), and were designed to be used in a manner that indirectly grounds the appliance frame to the neutral, which was common before the requirement of a separate safety ground was incorporated in the National Electrical Code.
As commonly used, 10-30 and 10-50 plugs required the frame of the appliance to be indirectly grounded via a strap connecting to the neutral blade. Safe operation relied on the neutral conductor in turn being connected to system ground at the circuit breaker or fuse box. If the neutral conductor were to break, disconnect, or develop high resistance, the appliance frame could become energized to dangerous voltages. Modern practice is to require a separate safety grounding conductor whose only purpose is to divert unsafe voltages, and which does not carry significant current during normal operation.
Relying on the neutral conductor was a legal grounding method for electric ranges and clothes dryers, under the National Electrical Code from the 1947 to the 1993 editions (banned in 1996 edition). Since North American dryers and ranges have certain components (timers, lights, fans, etc.) that run on 120 V, this means that the neutral wire indirectly used for grounding would also carry current, even under non-fault conditions. Although this is contrary to modern grounding practice, such "grandfathered" installations remain common in older homes in the United States.
NEMA 11
NEMA 11 series devices are three wire, three-pole, non-grounding devices for 3-phase 250-volt designs and equipment parts are specified by NEMA for 20-ampere (11-20), 30-ampere (11-30), and 50-ampere (11-50) devices.
NEMA 12
NEMA 12 series devices are three wire, three-pole, non-grounding devices for 3-phase, 480-volt equipment. According to NEMA, this is "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.
NEMA 13
NEMA 13 series devices are three wire, three-pole, non-grounding devices for 3-phase, 600-volt equipment. According to NEMA, this is "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.
NEMA 14
These sockets and plugs are four prong (see receptacle chart above) grounding devices (hot–hot–neutral–ground) available in ratings from 15 to 60 A. The voltage rating is 250 V. Of the straight-blade NEMA 14 devices, only 14-50 and 14-30 are in common use and either may be used for home charging of electric vehicles. The 14-30 is limited to 30 amperes (24 amperes continuous) and used mainly for some electric clothes dryers and some electric cooking stoves. The NEMA 14 connectors are essentially the replacements for the older NEMA 10 connectors described above, but with the addition of a dedicated grounding connection.
All NEMA 14 devices offer two hots, a neutral, and a ground, allowing for both 120 and 240 V when supplied by split-phase power, or 120 and 208 V if the supply is three-phase. The 14-30 has a rating of 30 A, and an L-shaped neutral blade. The 14-50 has a rating of 50 A, and a straight neutral blade sized so that it does not mate with 14-30 connectors.
NEMA 14-50 devices are frequently found in RV parks, since they are used for "shore power" connections of larger recreational vehicles. Also, it was formerly common to connect mobile homes to utility power via a 14-50 device. Newer applications include electric vehicle charging. The 6-50 is a smaller size receptacle lacking a neutral fourth prong, exclusively providing 240 V, also used for electric vehicle charging station purposes.
NEMA 15
NEMA 15 are three-pole and ground connectors (phase A, phase B, phase C, ground) rated for 208 V. Intended for delta three-phase circuits with ground and no neutral. The straight blades all carry one of the three phases.
NEMA 20
NEMA 20 series devices are specified for 347/600Y three-pole, four-wire, non-grounding devices. According to NEMA, this is "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.
NEMA 21
NEMA 21 series devices are specified for three-pole plus neutral, five-wire grounding devices for 3-phase 120/208Y supplies. According to NEMA, NEMA 21 straight-blade devices are "reserved for future configurations", so no designs for this series exist and no devices have been manufactured. There are however NEMA L21 series locking devices for 20- and 30-ampere devices specified and available for these applications.
NEMA 22
NEMA 22 series devices are specified for three-pole plus neutral, five-wire grounding devices for 3-phase 277/480Y supplies. According to NEMA, NEMA 22 straight-blade devices are "reserved for future configurations", so no designs for this series exist and no devices have been manufactured. There are however NEMA L22 series locking devices for 20- and 30-ampere devices specified and available for these applications.
NEMA 23
NEMA 23 series devices are specified for three-pole plus neutral, five-wire grounding devices for 3-phase 347/600Y supplies. According to NEMA, NEMA 23 straight-blade devices are "reserved for future configurations", so no designs for this series exist and no devices have been manufactured. There are however NEMA L23 series locking devices for 20- and 30-ampere devices specified and available for these applications.
NEMA 24
NEMA 24 Series devices are specified for two pole, three-wire grounding devices for 347V A/C power.
NEMA TT-30
The NEMA TT-30 (TT stands for Travel Trailer) connector is a 120 V 30 A recreational vehicle standard (hot-neutral-ground), also known as RV 30. The TT-30R receptacle is commonly available in nearly all RV parks in the United States and Canada, and all but the largest RVs manufactured since the 1970s use this plug to connect to power feeds.
The appearance of this plug is sometimes confused with a NEMA 10 connector, rated for 240 V, but the NEMA TT-30 is a 120 V device. The hot and neutral blades are angled at 45° from vertical and 90° to each other, unlike NEMA 10 devices (where the angles are 30° and 60° respectively), also the plug is slightly smaller than a NEMA 10 and larger than ordinary 5-15P plugs. The ground pin is round, like those on straight-blade NEMA grounding devices. Referring to the picture, the orientation is the same as the NEMA 5 plug and receptacle, with the neutral blade on the lower right.
Adapters are available with the TT-30P plug on one side and a 5-15R or 5-20R receptacle on the other side. When a power feed cord is detachable from an RV, an L5-30P is usually used on the RV end of the cord.
Twist-locking connectors
Twist-locking connectors were first invented by Harvey Hubbell III in 1938 and "Twist-Lock" remains a registered trademark of Hubbell Incorporated, although the term is used generically to refer to NEMA locking connectors manufactured by any company. Locking connectors use curved blades. Once pushed into the receptacle, the plug is twisted and its now-rotated blades latch into the receptacle. To unlatch the plug, the rotation is reversed. The locking coupling makes for a more reliable connection in commercial and industrial settings, where vibration or incidental impact could disconnect a non-locking connector.
Locking connectors come in a variety of standardized configurations that follow the same general naming scheme except that the designations include an "L" for "locking". Locking connectors are designed so that different voltages and current ratings can not be accidentally intermated. Many specific types exist; only a few are listed below. Other types include special purpose connectors for boats, 400 Hz circuits such as used for aircraft, and direct-current applications.
One apparent disadvantage of twist-lock connectors is that in the event that the cable is accidentally pulled too hard, rather than the plug falling out of the receptacle, exposed conductors may come out of the plug, causing dangerous shorts or shock hazards if the circuit is live. This is resolved in most cases by the connector having a robust integral strain relief.
ML
ML-series "Midget Locking" connectors are for 15 A applications where a larger locking connector would not fit.
ML-1 connectors are two-pole, no ground, rated for 125 V.
ML-2 connectors are two-pole with ground, rated for 125 V.
ML-3 connectors are for three-pole no ground (hot-neutral-hot) rated for 125/250 V.
SS
SS-series "Ship-to-shore" connectors are for 50 A marine shore-power applications.
SS1-50 connectors are two-pole with ground, rated for 125 V.
SS2-50 connectors are three-pole with ground (hot-neutral-hot) rated for 125/250 V.
NEMA L1
NEMA L1 series devices are single-pole plus neutral, two-wire, non-grounding devices for 125 volts single phase. Designs and devices for 15-ampere devices (L1-15) exist.
NEMA L2
NEMA L2 series devices are two-pole, two-wire, non-grounding devices for 250 volts single-phase. Designs and devices for 20-ampere devices (L2-20) exist.
NEMA L3 and L4
These devices would have been for 277- and 600-volt two-pole, two-wire non-grounding devices similar to the straight-blade NEMA 3 and 4 families, but were never specified by NEMA.
NEMA L5
NEMA L5 connectors are a series of two-pole and ground locking connectors rated for 125 V. L5-30R receptacles are common at marinas that provide power to docked boats. They are also found on some RVs for connecting to shore power. RVs in the US are equipped for 120 V 30 A or 240 V 50 A service, and use a cord to connect to a receptacle at the campsite, usually on a power pedestal with one or more receptacles providing 120 V 30 A (TT30R), 240 V 50 A (14-50R), or 120 V 15/20 A (5-20R) service. Locking receptacles appropriate for the voltage and current are used on the RV end of the cord, along with non-locking plugs on the end connecting to the pedestal.
NEMA L6
NEMA L6 connectors are rated for a maximum of 250 volts. They are intended for two-pole, three wire, line-line-earth (or hot-hot-ground) circuits with a nominal supply voltage of 208 or 240 volts, depending on phase configuration. The L6 connector does not provide a neutral connection.
L6-20 connectors provide a maximum of 20 amperes and are commonly found in power distribution units (PDUs) used in the information technology sector. Most often, these connectors can be found in server rooms and data centers where the connectors are used to power equipment such as servers, backup systems and UPS units.
L6-30 connectors provide a maximum of 30 amperes and tend to be used in heavy-industry sectors. For example, welders and other manufacturing machinery where industrial equipment or large power tools are commonplace.
NEMA L7
NEMA L7 are two-pole and ground connectors rated for 277 V. Typically, these connectors are found in commercial or industrial lighting circuits, especially where metal halide lamps are common.
NEMA L8
NEMA L8 are two-pole and ground connectors rated for 480 V. Intended for three-wire hot-hot-ground circuits.
NEMA L9
NEMA L9 are two-pole and ground connectors rated for 600 V. Intended for three-wire hot-hot-ground circuits.
NEMA L10
NEMA L10 series devices are two-pole plus neutral, three-wire, non-grounding devices for 125/250 volts single-phase. These are deprecated due to the lack of grounding but L10-20 and L10-30 devices are specified by NEMA and are commercially available.
NEMA L11
NEMA L11 series devices are three-pole, three-wire, non-grounding devices for three-phase 250-volt devices. Designs exist for 15-ampere (L11-15), 20-ampere (L11-20), and 30-ampere (L11-30) devices, and L11-20 and L11-30 devices were commercially available from at least one manufacturer (Bryant Electric).
NEMA L12
NEMA L12 series devices are three-pole, three-wire, non-grounding devices for three-phase 480-volt devices. Designs exist for 20-ampere (L12-20), and 30-ampere (L12-30) devices, and L12-20 and L12-30 devices were commercially available from at least one manufacturer (Bryant Electric).
NEMA L13
NEMA L13 series devices are three-pole, three-wire, non-grounding devices for three-phase 600-volt devices. Designs exist for 30-ampere (L13-30) devices and L13-30 devices were commercially available from at least one manufacturer (Bryant Electric).
NEMA L14
NEMA L14 are three-pole and ground connectors rated for 125/250 V. Intended for three-pole, four-wire hot-hot-neutral-ground circuits with a nominal supply voltages of 240 or 208 V hot-to-hot and 120 V hot-to-neutral.
These connectors are common on household backup generators, and on racks of power amplifiers in large audio systems.
NEMA L15
NEMA L15 are three-pole and ground connectors rated for 250 V. Intended for three-phase circuits.
NEMA L16
NEMA L16 are three-pole and ground connectors rated for 480 V. Intended for three-phase circuits.
NEMA L17
NEMA L17 are three-pole and ground connectors rated for 600 V. Intended for three-phase circuits.
NEMA L18
NEMA L18 are four-pole no ground connectors rated for 120/208 V. Intended for wye three-phase circuits.
NEMA L19
NEMA L19 series devices are three-pole, four-wire, non-grounding devices for three-phase 277/480-volt devices. Designs exist for 20-ampere (L19-20), and 30-ampere (L19-30) devices, and L19-20 and L19-30 devices were commercially available from at least one manufacturer (Bryant Electric).
NEMA L20
NEMA L20 series devices are three-pole, four-wire, non-grounding devices for three-phase 347/600-volt devices. Designs exist for 20-ampere (L12-20), and 30-ampere (L20-30) devices, and L20-20 and L20-30 devices were commercially available from at least one manufacturer (Bryant Electric).
NEMA L21
NEMA L21 are four-pole and ground connectors rated for 120/208 V. Intended for wye three-phase circuits with both neutral and ground. The pin in the middle is ground, and the blade with a right angle on the tab is neutral. These connectors are common in live event power distribution. Many event production companies use power distributors with camlock connectors for feeder cable, and 12 or more L21-30 connectors which can each be broken out to three individual 120 V circuits via the use of a stringer box.
NEMA L22
NEMA L22 are four-pole and ground connectors rated for 277/480 V. Intended for wye three-phase circuits with both neutral and ground. The pin in the middle is ground, and the blade with a right angle on the tab is neutral.
NEMA L23
NEMA L23 are four-pole and ground connectors rated for 347/600 V. Intended for wye three-phase circuits with both neutral and ground. The pin in the middle is ground, and the blade with a right angle on the tab is neutral.
Additional safety features
Over time, electrical codes in the US and Canada began to require additional safety features in the basic NEMA 5-15R and 5-20R configurations to address specific electric shock hazard concerns. The safety features listed below are not mutually exclusive; for example, tamper-resistant GFCI receptacles are available.
Ground fault circuit interrupter (GFCI) receptacles
These versions of the 5-15R or 5-20R receptacle are residual-current devices, and have "Test" and "Reset" buttons (and sometimes an indicator light which may be normally on or normally off per the vendor's design). In the US and Canada, GFCI protection is required for receptacles in many potentially wet locations, including outside outlets, bathrooms, and some places in kitchens, basements, and crawl spaces. This is an expedient way to provide that protection at the receptacle itself.
These safety devices work by comparing the currents flowing in the live and neutral conductors, and disconnect the circuit if their difference exceeds 4 to 6 milliamperes. Installing a single receptacle is often cheaper or more convenient than providing this GFCI protection at the circuit breaker. In addition, a tripped GFCI receptacle may be more easily noticed and reset, as compared to a tripped GFCI located in a remote circuit breaker panel far from the point of usage.
Like most current interrupting devices, a GFCI receptacle can optionally be wired to feed additional "downstream" outlets; correctly installing one GFCI receptacle in a circuit can protect all the plugs, lights, switches, and wiring which receive power from it. This allows for cost-effective retrofits on older installations where branch circuits were often daisy-chained between wet and dry locations. A GFCI receptacle may be installed indoors where it is sheltered from dampness and corrosion, while still protecting an outdoors receptacle wired downstream.
GFCIs are also recommended for power tool outlets and any locations where children might insert conductive objects into the receptacles.
Tamper-resistant receptacles
Starting with the 2008 National Electrical Code and the 2009 Canadian Electrical Code, listed tamper-resistant receptacles that address electric shock hazards to children must now be installed in almost all areas of new or renovated dwellings. According to statistics cited by the NFPA, the code change adds only $40 to the cost of building an average, 75-receptacle home in the US.
This safety measure reduces shock hazards to a child that attempts to insert a single conductive object into the receptacle. Inserting a normal, two-blade electrical plug applies simultaneous pressure on both sides of the receptacle to open an internal, spring-loaded shutter, but a foreign object fails to do so and therefore cannot make contact with the live electrical contacts. However, the device can still be defeated by inserting two objects simultaneously. Despite its weaknesses, the tamper-resistant receptacle is superior to protective plastic outlet caps which must be individually installed on each receptacle (and are a choking hazard when removed), and to sliding covers that children easily learn to defeat.
AFCI receptacles
The National Electrical Code has been updated for 2014 to address the use of Outlet Branch Circuit (OBC) Arc Fault Circuit Interrupter (AFCI) receptacles as an alternative to traditional circuit breakers when used for modifications, extensions, replacement receptacles, or in new construction. AFCI receptacles reduce the dangers associated with potentially-hazardous arcing conditions (parallel arcs and series arcs), by interrupting power to arcing devices (e.g. a damaged appliance cord) that might otherwise not draw enough current to trip the primary circuit protection device.
AFCI protection is mandated by the 2014 Code in residential family rooms, dining rooms, living rooms, kitchens, parlors, libraries, dens, bedrooms, laundry rooms, sunrooms, recreation rooms, closets, hallways or similar rooms. It is also required in dormitory units. AFCI receptacles look similar to GFCI receptacles in that they have a "Test" and "Reset" button on the face of the device for localized testing. This saves a homeowner a trip to the breaker panel, should the device trip. Unlike AFCI breakers, AFCI receptacles can be used on any wiring system, regardless of the panel. When installed as the first receptacle on a branch circuit, AFCI receptacles can provide series arc protection for the entire branch circuit. They also provide parallel arc protection for the branch circuit downstream of the AFCI receptacle.
Surge protective receptacles
Surge protective devices are designed to reduce the random energy surges of voltage transients and electrical noise on the power supply line, which can damage sensitive electronics such as TVs, computers, and smart appliances. They are available for 120 V, 15/20 A applications, in different form factors such as surge protective receptacles in single, duplex, four-in-one, and six receptacle configurations, as well as surge-protective power strips. These devices provide point-of-use protection and are the last line of defense in a whole-house surge protection network.
Weather-resistant receptacles
Weather-resistant (WR) receptacles are made with ultraviolet-resistant insulating materials having excellent cold-temperature impact resistance to withstand longterm exposure to weathering and abuse. Metallic components are required to be resistant to corrosion. Mandated by the 2008 National Electrical Code in outdoor damp or wet locations, WR receptacles are required in patio, deck, and pool areas. They are available in a variety of variations, including GFCI and tamper-resistant.
For added protection, WR receptacles should be shielded by "Extra-Duty While In-Use" or "Weather-Resistant" covers. These covers are ruggedly constructed to keep out moisture (either dripping or condensing), dust, debris, and insects, while providing easy access to receptacles to allow their use with power tools, trimmers, sprinkler systems, and pumps.
Leak-current detection and interruption (LCDI) cordsets
Damaged power cords of portable air conditioners have caused many electrical fires, and about 350 deaths per year. To combat this, the 2017 National Electrical Code (NEC) requires each portable air conditioner sold in the United States to have either a leakage current detector interrupter (LCDI) or a ground-fault circuit interrupter (GFCI) protective device built into its power cord. The device can be integral with the power plug, or a separate module within 12 inches of the plug. The protection device is equipped with "Test" and "Reset" buttons on the housing. An LCDI cord has a fine wire mesh around the conductors, and circuitry to detect current leaking from the conductors to the mesh, which would happen if the cord were damaged or frayed. The plugs are normal NEMA 5-15, 5-20, 6-15, 6-20, or 6-30 plugs, depending on the air conditioner design, and are typically molded-on designs.
Color code
The color of a device neither identifies its voltage class nor power system. Because the colors are not specified by NEMA standards, the purpose of color-coding a receptacle may be set by the building owner, who may select brown, ivory, white, almond, grey, or black receptacles in the 5-15 configuration to blend with the decor of a room.
However, although colors are not standardized by NEMA, some industries utilize colors for certain applications, following de facto standards:
A receptacle with a green dot is a so-called "hospital grade" device; The primary reason to use a hospital-grade receptacle at a patient bed location is to ensure that a receptacle with a greater contact tension is provided to minimize possibilities that an attachment plug supplying medical or life support equipment may be disconnected because the attachment plug slipped out of the receptacle. Also such devices are tested to survive harder use while limiting electrical leakage, compared to wiring devices intended for residential or commercial purposes.
Per UL Standard ANSI/UL 498, a receptacle (any color) with an orange triangle, is an isolated ground (IG) device, where the grounding pin of the receptacle is connected to ground independently of the frame of the receptacle and wiring outlet box. This is also a requirement of the National Electrical Code (NFPA 70), Article 406. While neither UL nor the CSA require the face of the receptacle to be a specific color, most IG receptacles are orange.
A blue receptacle may indicate built-in surge suppressors.
A red receptacle may indicate a special-service outlet such as one connected to an emergency standby power source. The Canadian Electrical Code requires that "essential" receptacles in hospitals, connected to emergency power systems, must be red.
At least one manufacturer makes a yellow receptacle, which identifies it as corrosion-resistant.
Break-away tabs
Most duplex receptacles have metal tabs connecting the top and bottom receptacles. These tabs can be broken off to allow the top and bottom receptacles to be wired onto separate circuits. This may allow for one switched receptacle for a lamp, or for two separate supply circuits when heavy loads are anticipated. Two branch circuits may optionally share a common neutral wire terminating on duplex receptacles, a condition sometimes referred to as "split-wiring", "split-receptacle", or "half-split".
Related standards
The dimensions and configurations for NEMA connectors are given in ANSI/NEMA standard WD-6. Underwriters Laboratories maintains UL Standard 498, which specifies construction performance (e.g. durability, electrical safety, and fire-resistance) for NEMA connectors. These additional requirements allow connectors to be manufactured to be compliant with the National Electrical Code. The Defense Logistics Agency and General Services Administration maintain Federal Specification W-C-596 and its associated specification sheets. This specification references WD-6 and UL 498, and provides additional durability and electrical safety performance criteria for connectors intended for military use.
See also
AC power plugs and sockets
BS 1363, British three-pin plugs and sockets
CEE 7 standard AC plugs and sockets
IEC 60320, an international standard for power "inlet" connectors on equipment
, which includes some non-NEMA plugs and sockets used in North America
Mains electricity by country
References
External links
NEMA Chart at mahonkin.com
NEMA Chart at generatorjoe.net
Introduction to NEMA connectors
Mains power connectors
Mechanical standards
NEMA standards | NEMA connector | [
"Engineering"
] | 10,275 | [
"Mechanical standards",
"Mechanical engineering"
] |
5,551,542 | https://en.wikipedia.org/wiki/Bluebird%20of%20happiness | The symbol of a bluebird as the harbinger of happiness is found in many cultures and may date back thousands of years.
Origins of idiom
Chinese mythology
One of the oldest examples of a blue bird in myth (found on oracle bone inscriptions of the Shang dynasty, 1766–1122 BC) is from pre-modern China, where a blue or green bird (qingniao) was the messenger bird of Xi Wangmu (the 'Queen Mother of the West'), who began life as a fearsome goddess and immortal. By the Tang dynasty (618–906 AD), she had evolved into a Daoist fairy queen and the protector/patron of "singing girls, dead women, novices, nuns, adepts and priestesses...women [who] stood outside the roles prescribed for women in the traditional Chinese family". Depictions of Xi Wangmu often include a bird—the birds in the earliest depictions are difficult to identify, and by the Tang dynasty, most of the birds appear in a circle, often with three legs, as a symbol of the sun.
Native American folklore
Among some Native Americans, the bluebird has mythological or literary significance.
According to the Cochiti tribe, the firstborn son of Sun was named Bluebird. In the tale "The Sun's Children", from Tales of the Cochiti Indians (1932) by Ruth Benedict, the male child of the sun is named Bluebird (Culutiwa).
The Navajo identify the mountain bluebird as a spirit in animal form, associated with the rising sun. The "Bluebird Song" is sung to remind tribe members to wake at dawn and rise to greet the sun:
The "Bluebird Song" is still performed in social settings, including the nine-day Ye'iibicheii winter Nightway ceremony, where it is the final song, performed just before sunrise of the ceremony's last day.
Most O'odham lore associated with the "bluebird" likely refers not to the bluebirds (Sialia) but to the blue grosbeak.
European folklore
In Russian fairy tales, the blue bird is a symbol of hope. More recently, Anton Denikin has characterized the Ice March of the defeated Volunteer Army in the Russian Civil War as follows:We went from the dark night of spiritual slavery to unknown wandering – in search of the bluebird.
In L'Oiseau Bleu ("The Blue Bird") a popular tale included by Madame d'Aulnoy (1650–1705) in her collection Tales of the Fairies, King Charming is transformed into a blue bird, who aids his lover, the princess Fiordelisa, in her trials.
Most to the point, a "blue bird of happiness" features in ancient Lorraine folklore. In 1886, Catulle Mendès published Les oiseaux bleus ("the blue birds"), a story bundle inspired by these traditional tales. In 1892, Marcel Schwob, at the time secretary to Mendès, published the collection Le roi au masque d'or, which included the story "Le pays bleu", dedicated to his friend Oscar Wilde. Maurice Maeterlinck had entered Mendès literary circle as well and in 1908 he published a symbolist stage play named The Blue Bird inspired by the same material. Two children, Tyltyl and Mytyl, are sent out by the fairy Bérylune (Jessie Ralph) to search for the Bluebird of Happiness. Returning home empty-handed, the children see that the bird has been in a cage in their house all along and they create great happiness for another by giving their pet bird to the sick neighbor child. Translated into English by Alexander Teixeira de Mattos, it played on Broadway from 1910. In the programme for the (revival of the) play at London's Haymarket Theatre in 1912, the programme explained: "The Blue Bird, inhabitant of the pays bleu, the fabulous blue country of our dreams, is an ancient symbol in the folk-lore of Lorraine, and stands for happiness." The play was quickly adapted into a children's novel, an opera, and at least seven films between 1910 and 2002.
See the German equivalent (blue flower).
In popular culture
The immense popularity of Maeterlinck's play probably originated the idiom in English. In 1934, this was strengthened by the popular American song "Bluebird of Happiness". Written by Sandor Harmati and Edward Heyman, it was recorded several times by American tenor Jan Peerce, for RCA Victor and also by Art Mooney and His Orchestra.
The bluebird is featured in the song "Be Like The Bluebird" in the popular musical Anything Goes.
The lyrics "Somewhere, over the rainbow, bluebirds fly" in Harold Arlen and Yip Harburg's 1938 song for the 1939 film The Wizard of Oz is a likely allusion to the idiom as well.
Shirley Temple starred in the 1940 American fantasy The Blue Bird.
In 1942, the popular song "(There'll Be Bluebirds Over) The White Cliffs of Dover" used them, despite an absence of real blue birds on those cliffs, among other imagery to lift spirits.
The Academy Award-winning song, "Zip-a-Dee-Doo-Dah," from Walt Disney's 1946 live-action and animated film Song of the South, makes reference to "Mr. Bluebird on my shoulder" as a symbol of good cheer.
In the 1946 Japanese film No Regrets for Our Youth, directed by Akira Kurosawa, when Yukie and Noge reunite in Tokyo during the war, Yukie laments that she is not happy with her career and wants to do something truly meaningful in the struggle for freedom. Noge responds, "Who finds work like that even once in their lives? It's like finding The Blue Bird of Happiness."
The bluebird is mentioned at the end of the 1968 Beatles film Yellow Submarine, when the leader of the Blue Meanies, the Chief Blue Meanie claims that his "cousin is the bluebird of happiness". Beatles Paul McCartney wrote a song about them for his band Wings’ 1973 album Band on the Run, "Bluebird".
The Velvet Underground song “Candy Says” contains a line pertaining to watching the blue birds fly as a metaphor for happiness passing by Candy Darling, the song’s subject, while she is in the wrong body.
The Allman Brothers Band's 1972 song "Blue Sky" has the lyric "Don't fly, mister blue bird, I'm just walking down the road".
A scene in the 1977 Disney film The Rescuers uses the bluebird as a symbol of "faith ... you see from afar."
In the 1985 film Sesame Street Presents: Follow that Bird, the Sleaze Brothers kidnap Big Bird and press him into service in their fun fair, where he is painted blue and billed as the Blue Bird of Happiness. In a play on the word "blue," Big Bird sings the mournful song "I'm So Blue."
The lyrics of the They Might Be Giants 1989 song "Birdhouse in Your Soul" by John Linnell includes the phrase "blue bird of friendliness."
The 2001 film K-PAX, directed by Iain Softley, written by Charles Leavitt and based on the book of the same name by Gene Brewer, contains a scene in which the lead character prot (played by Kevin Spacey), claiming to be a visitor from outer space. He ends up in a psychiatric ward where he 'prescribes' a fellow patient with the task of finding a 'Bluebird Of Happiness'. In a later scene, the fellow patient excitedly yells out that he finally found the Bluebird, resulting in pandemonium amongst patients spanning several floors of the institution.
The bluebird is also mentioned in The Melancholy of Haruhi Suzumiya episode "The Melancholy of Haruhi Suzumiya Part III" in 2006.
Musician Neil Young has a song "Beautiful Bluebird" about a lost love on his 2007 album Chrome Dreams II.
"Blue Bird" is a song by Hope Sandoval & the Warm Inventions from their 2009 album Through the Devil Softly.
A blue bird like device can be found in "The Bluebird of Zappiness" a 2010 episode of Cyberchase. The main antagonist of the episode, which is Ledge now that Hacker has teamed up with the main protagonists to form an temporary alliance, dream is to discover the bluebird before Hacker does. They all want to find it, so they wake up at dawn, coincidentally because the episode is all about finding the length of your shadows. One the protagonists, Inez ultimately tries to beat Ledge to the device through a climbing race contest, but there ultimately a tie and the bluebird gets lost once again.
The character Luna from the 2012 video game and visual novel Zero Escape: Virtue's Last Reward wears a necklace with a caged bluebird, and the story is discussed in one ending.
The titular bluebird of the song "Birds", from the 2013 album Government Plates by the experimental hip hop group Death Grips, is thought to be referencing Charles Bukowski's poem "Bluebird", wherein the bluebird represents the vulnerability that Bukowski felt as a result of child abuse from his father.
In the 2015 video game, “Ensemble Stars!”, the character Tsumugi Aoba is commonly referred to as the bluebird of happiness, as a pun on his last name.
The bluebird is also mentioned by David Bowie in the song "Lazarus" from his 2016 album Blackstar.
In the 2018 video game Red Dead Redemption 2, during the scene where John Marston builds the ranch at Beecher's Hope, a bluebird is seen perched next to the gang while they are hammering and nailing the wood.
As a parallel, main characters relationship-analogy fairy tale, and an identically named, diegetic wind ensemble piece in which the main characters must play a dialog, in the 2018 anime movie Liz and the Blue Bird, a spinoff in the Sound! Euphonium franchise.
In a cartoon from Gary Larson, the (absent) bluebird of happiness is mentioned as counterpart of the "chicken of depression".
The character Meteion from the 2021 Final Fantasy XIV expansion pack Final Fantasy XIV: Endwalker is a blue-colored harpy-esque familiar who can transform herself into a blue-colored bird and has the power to read emotions.
Bluebirds in nature
Three species of blue-headed North American thrushes (Turdidae) occupy the genus Sialia. The most widespread and best-known is the eastern bluebird (Sialia sialis), breeding from Canada's prairie provinces to Texas and from the Maritimes to Florida; discrete populations of this species are also found from southeastern Arizona through west Mexico into Guatemala and Nicaragua. The mountain bluebird (S. currucoides) breeds on high-elevation plains from central Alaska to Arizona and New Mexico, and the western bluebird (S. mexicana) inhabits dry coniferous forests from extreme southwestern Canada to Baja California and from the Great Basin south into west Mexico. Other all-blue birds in North and Central America are the blue mockingbird, blue bunting, indigo bunting, blue grosbeak and a number of jays, including the blue jay.
Europe has only a few birds with conspicuous blue in the plumage, including the great tit (Parus major), the various blue tits of the genus (Cyanistes) and the common kingfisher. The adult male of the blue rock-thrush is the only European passerine with all-blue plumage; this species is best known from its literary treatment by Giacomo Leopardi, whose poem Il passero solitario makes of the rock-thrush a figure of the poet's isolation.
In South and Southeast Asia, the fairy-bluebirds, blue whistling thrush and verditer flycatcher are strikingly blue.
Poems mentioning bluebirds
References
Bluebirds
European folklore
Metaphors referring to birds
Legendary birds
Symbols | Bluebird of happiness | [
"Mathematics"
] | 2,490 | [
"Symbols"
] |
5,551,560 | https://en.wikipedia.org/wiki/Biotic%20material | Biotic material or biological derived material is any material that originates from living organisms. Most such materials contain carbon and are capable of decay.
The earliest form of life on Earth arose at least 3.5 billion years ago. Earlier physical evidences of life include graphite, a biogenic substance, in 3.7 billion-year-old metasedimentary rocks discovered in southwestern Greenland, as well as, "remains of biotic life" found in 4.1 billion-year-old rocks in Western Australia. Earth's biodiversity has expanded continually except when interrupted by mass extinctions. Although scholars estimate that over 99 percent of all species of life (over five billion) that ever lived on Earth are extinct, there are still an estimated 10–14 million extant species, of which about 1.2 million have been documented and over 86% have not yet been described.
Examples of biotic materials are wood, straw, humus, manure, bark, crude oil, cotton, spider silk, chitin, fibrin, and bone.
The use of biotic materials and processed biotic materials (bio-based material) as alternative natural materials over synthetics is widespread with those who are environmentally conscious because such materials are usually biodegradable, renewable, and the processing is commonly understood and has minimal environmental impact. However, not all biotic materials are used in an environmentally friendly way, such as those that require high levels of processing, are harvested unsustainably, or are used to produce carbon emissions.
When the source of the recently living material has little importance to the product produced, such as in the production of biofuels, biotic material is simply called biomass. Many fuel sources may have biological sources and may be divided roughly into fossil fuels and biofuel.
In soil science, biotic material is often referred to as organic matter. Biotic materials in soil include humic substances such as humic acids, fulvic acids and humin. Some biotic material may not be considered to be organic matter if it is low in organic compounds, such as a clam's shell, which is an essential component of the exoskeleton of bivalve mollusks made of calcium carbonate (), but contains little organic carbon.
See also
Abiotic component
References
Biomolecules
Composting
Natural materials
Sustainable technologies | Biotic material | [
"Physics",
"Chemistry",
"Biology"
] | 482 | [
"Natural products",
"Natural materials",
"Organic compounds",
"Materials",
"Biomolecules",
"Structural biology",
"Biochemistry",
"Matter",
"Molecular biology"
] |
5,551,810 | https://en.wikipedia.org/wiki/PELP-1 | Proline-, glutamic acid- and leucine-rich protein 1 (PELP1) also known as modulator of non-genomic activity of estrogen receptor (MNAR) and transcription factor HMX3 is a protein that in humans is encoded by the PELP1 gene. is a transcriptional corepressor for nuclear receptors such as glucocorticoid receptors and a coactivator for estrogen receptors.
Proline-, glutamic acid-, and leucine-rich protein 1 (PELP1) is transcription coregulator and modulates functions of several hormonal receptors and transcription factors. PELP1 plays essential roles in hormonal signaling, cell cycle progression, and ribosomal biogenesis. PELP1 expression is upregulated in several cancers; its deregulation contributes to hormonal therapy resistance and metastasis; therefore, PELP1 represents a novel therapeutic target for many cancers.
Gene
PELP1 is located on chromosome 17p13.2 and PELP1 is expressed in a wide variety of tissues; its highest expression levels are found in the brain, testes, ovaries, and uterus. Currently, there are two known isoforms (long 3.8 Kb and short 3.4 Kb) and short isoform is widely expressed in cancer cells.
Structure
The PELP1 protein encodes a protein of 1130 amino acids, and exhibits both cytoplasmic and nuclear localization depending on the tissue. PELP1 lacks known enzymatic activity and functions as a scaffolding protein. It contains 10 NR-interacting boxes (LXXLL motifs) and functions as a coregulator of several nuclear receptors via its LXXLL motifs including ESR1, ESR2, ERR-alpha, PR, GR, AR, and RXR. PELP1 also functions as a coregulator of several other transcription factors, including AP1, SP1, NFkB, STAT3, and FHL2.
PELP1 has a histone binding domain and interacts with chromatin-modifying complexes, including CBP/p300, histone deacetylase 2, histones, SUMO2, lysine-specific demethylase 1 (KDM1), PRMT6, and CARM1. PELP1 also interacts with cell cycle regulators such as pRb. E2F1, and p53.
PELP1 is phosphorylated by hormonal and growth factor signals. PELP1 phosphorylation status is also influenced by cell cycle progression, and it is a substrate of CDKs. Further, PELP1 is phosphorylated by DNA damage induced kinases (ATM, ATR, DNA-PKcs).
Function
PELP1 functions as a coactivator of several NRs and regulates genes involved in proliferation and cancer progression. PELP1 enhances transcription functions of ESR1, ESR2, AR, GR, E2F and STAT3. PELP1 participates in activation of ESR1 extra-nuclear actions by coupling ESR1 with Src kinase PI3K STAT3 ILK1 and mTOR PELP1 participates in E2-mediated cell proliferation and is a substrate of CDK4/cyclin D1, CDK2/cyclin E and CDK2/cyclin A complexes. Studies using TG mice model suggested the existence of an autocrine loop involving the CDK–cyclin D1–PELP1 axis in promoting mammary tumorigenesis
PELP1 has a histone binding domain; functions as a reader of histone modifications, interacts with epigenetic modifiers such as HDAC2, KDM1, PRMT6, CARM1; and facilitates activation of genes involved in proliferation and cancer progression. PELP1 modulates the expression of miRs, PELP1-mediated epigenetic changes play important role in the regulation miR expression and many of PELP1 mediated miRS are involved in promoting metastasis. PELP1 is needed for optimal DNA damage response, is phosphorylated by DDR kinases and is important for p53 coactivation function. PELP1 also interacts with MTp53, regulates its recruitment, and alters MTp53 target gene expression. PELP1 depletion contributes to increased stability of E2F1. PELP1 binds RNA, and participates in RNA splicing. The PELP1-regulated genome includes several uniquely spliced isoforms. Mechanistic studies showed that PELP1 interaction with the arginine methyltransferase PRMT6 plays a role in RNA splicing.
PELP1 plays critical roles in 60S ribosomal subunit synthesis and ribosomal RNA transcription. The SENP3-associated complex comprising PELP1, TEX10 and WDR18 is involved in maturation and nucleolar release of the large ribosomal subunit. SUMO conjugation/deconjugation of PELP1 controls its dynamic association with the AAA ATPase MDN1, a key factor of pre-60S remodeling. Modification of PELP1 promotes the recruitment of MDN1 to pre-60S particles, while deSUMOylation is needed to release both MDN1 and PELP1 from pre-ribosomes.
PELP1 is widely expressed in many regions of brain, including the hippocampus, hypothalamus, and cerebral cortex. PELP1 interacts with ESR1, Src, PI3K and GSK3β in the brain. It is essential for E2-mediated extra-nuclear signaling following global cerebral ischemic. PELP1 plays an essential role in E2-mediated rapid extranuclear signaling, neuroprotection, and cognitive function in the brain. Ability of E2 to exert anti-inflammatory effects was lost in PELP1 forebrain-specific knockout mice, indicating a key role for PELP1 in E2 anti-inflammatory signaling.
PELP1 is a proto-oncogene that provides cancer cells with a distinct growth and survival advantage. PELP1 interacts with various enzymes that modulate the cytoskeleton, cell
migration, and metastasis. PELP1 deregulation in vivo promotes development of mammary gland hyperplasia and carcinoma PELP1 is implicated in progression of breast, endometrial, ovarian, salivary prostate, lung, pancreas, and colon neoplasms.
PELP1 signaling contributes to hormonal therapy resistance. Altered localization of PLP1 contributes to tamoxifen resistance via excessive activation of the AKT pathway and cytoplasmic PELP1 induces signaling pathways that converge on ERRγ to promote cell survival in the presence of tamoxifen. AR, PELP1 and Src form constitutive complexes in prostate neoplasms model cells that exhibit androgen independence. Cytoplasmic localization of PELP1 upregulates pro-tumorigenic IKKε and secrete inflammatory signals, which through paracrine macrophage activation, regulate the migratory phenotype associated with breast cancer initiation.
Clinical significance
PELP1 is a proto-oncogene that provides cancer cells with a distinct growth and survival advantage. PELP1 overexpression has been reported in many cancers. PELP1 expression is an independent prognostic predictor of shorter breast cancer–specific survival and disease free interval. Patients whose tumors had high levels of cytoplasmic PELP1 exhibited a tendency to respond poorly to tamoxifen and PELP1 deregulated tumors respond to Src kinase and mTOR inhibitors. Treatment of breast and ovarian cancer xenografts with liposomal PELP1–siRNA–DOPC formulations revealed that knockdown of PELP1 significantly reduce the tumor growth. These results provided initial proof that PELP1 is a bonafide therapeutic target. Emerging data support a central role for PELP1 and its direct protein–protein interactions in cancer progression. Since PELP1 lacks known enzymatic activity, drugs that target PELP1 interactions with other proteins should have clinical utility. Recent studies described an inhibitor (D2) that block PELP1 interactions with AR. Since PELP1 interacts with histone modifications and epigenetic enzymes, drugs targeting epigenetic modifier enzymes may be useful in targeting PELP1 deregulated tumors.
Notes
References
External links
NURSA PELP1:
Gene expression
Transcription coregulators | PELP-1 | [
"Chemistry",
"Biology"
] | 1,805 | [
"Gene expression",
"Molecular genetics",
"Cellular processes",
"Molecular biology",
"Biochemistry"
] |
5,552,077 | https://en.wikipedia.org/wiki/Trace%20amine | Trace amines are an endogenous group of trace amine-associated receptor 1 (TAAR1) agonists – and hence, monoaminergic neuromodulators – that are structurally and metabolically related to classical monoamine neurotransmitters. Compared to the classical monoamines, they are present in trace concentrations. They are distributed heterogeneously throughout the mammalian brain and peripheral nervous tissues and exhibit high rates of metabolism. Although they can be synthesized within parent monoamine neurotransmitter systems, there is evidence that suggests that some of them may comprise their own independent neurotransmitter systems.
Trace amines play significant roles in regulating the quantity of monoamine neurotransmitters in the synaptic cleft of monoamine neurons with . They have well-characterized presynaptic amphetamine-like effects on these monoamine neurons via TAAR1 activation; specifically, by activating TAAR1 in neurons they promote the release and prevent reuptake of monoamine neurotransmitters from the synaptic cleft as well as inhibit neuronal firing. Phenethylamine and amphetamine possess analogous pharmacodynamics in human dopamine neurons, as both compounds induce efflux from vesicular monoamine transporter 2 (VMAT2) and activate TAAR1 with comparable efficacy.
Like dopamine, norepinephrine, and serotonin, the trace amines have been implicated in a vast array of human disorders of affect and cognition, such as ADHD, depression and schizophrenia, among others. Trace aminergic hypo-function is particularly relevant to ADHD, since urinary and plasma phenethylamine concentrations are significantly lower in individuals with ADHD relative to controls and the two most commonly prescribed drugs for ADHD, amphetamine and methylphenidate, increase phenethylamine biosynthesis in treatment-responsive individuals with ADHD. A systematic review of ADHD biomarkers also indicated that urinary phenethylamine levels could be a diagnostic biomarker for ADHD.
List of trace amines
The human trace amines include:
Phenethylamines (related to catecholamines):
Phenethylamine (PEA)
N-Methylphenethylamine (endogenous amphetamine isomer)
Phenylethanolamine
m-Tyramine
p-Tyramine
3-Methoxytyramine
N-Methyltyramine
m-Octopamine
p-Octopamine
Synephrine
Tryptamine
While not trace amines themselves, the classical monoamines norepinephrine, serotonin, and histamine are all partial agonists at the human TAAR1 receptor; dopamine is a high-affinity agonist at human TAAR1. and are endogenous amines in humans, however, their human TAAR1 binding has not been determined
Concentrations
Trace amines are so-named because they are present in the nervous system at trace or very concentrations. These concentrations are much lower than for classical monoamine neurotransmitters like serotonin, dopamine, and norepinephrine. However, the rapid metabolic turnover of trace amines, consequent to strong susceptibility to monoamine oxidases, is suggestive that they may be present as chemical synapses at much higher concentrations than predicted by steady-state measures.
History
A thorough review of trace amine-associated receptors that discusses the historical evolution of this research particularly well is that of Grandy.
See also
Neurotransmitter
Monoamine neurotransmitters
Trace amine-associated receptor (TAAR)
TAAR1
Notes
References
TAAR1 agonists
Amines
Amphetamine
Neurotransmitters
Neurochemistry | Trace amine | [
"Chemistry",
"Biology"
] | 813 | [
"Neurotransmitters",
"Functional groups",
"Amines",
"Biochemistry",
"Neurochemistry",
"Bases (chemistry)"
] |
5,552,733 | https://en.wikipedia.org/wiki/Bradytroph | A bradytroph is a strain of an organism that exhibits slow growth in the absence of an external source of a particular metabolite. This is usually due to a defect in an enzyme required in the metabolic pathway producing this chemical. Such defects are the result of mutations in the genes encoding these enzymes. As the organism can still produce small amounts of the chemical, the mutation is not lethal. In these bradytroph strains, rapid growth occurs when the chemical is present in the cell's growth media and the missing metabolite can be transported into the cell from the external environment. A bradytroph may also be referred to as a "leaky auxotroph".
The first usage of "bradytroph" was to describe Escherichia coli mutants partially defective in arginine biosynthesis. Among many other examples of bradytrophic strains of microorganisms are Bacillus subtilis strains with mutations affecting thiamine production and Saccharomyces cerevisiae strains with mutations that impair arginine biosynthesis.
See also
Autotroph
Auxotrophy
References
Cell biology | Bradytroph | [
"Biology"
] | 234 | [
"Cell biology"
] |
5,552,783 | https://en.wikipedia.org/wiki/Basal%20shoot | Basal shoots, root sprouts, adventitious shoots, and suckers are words for various kinds of shoots that grow from adventitious buds on the base of a tree or shrub, or from adventitious buds on its roots. Shoots that grow from buds on the base of a tree or shrub are called basal shoots; these are distinguished from shoots that grow from adventitious buds on the roots of a tree or shrub, which may be called root sprouts or suckers. A plant that produces root sprouts or runners is described as surculose. Water sprouts produced by adventitious buds may occur on the above-ground stem, branches or both of trees and shrubs. Suckers are shoots arising underground from the roots some distance from the base of a tree or shrub.
In botany and ecology
In botany, a root sprout or sucker is a severable plant that grows not from a seed but from the meristem of a root at the base of or a certain distance from the original tree or shrub. Root sprouts may emerge a substantial distance from the base of the originating plant, are a form of vegetative dispersal, and may form a patch that constitutes a habitat in which that surculose plant is the dominant species. Root sprouts also may grow from the roots of trees that have been felled. Tree roots ordinarily grow outward from their trunks a distance of 1.5 to 2 times their heights, and therefore root sprouts can emerge a substantial distance from the trunk.
This is a phenomenon of natural "asexual reproduction", also denominated "vegetative reproduction". It is a strategy of plant propagation. The complex of clonal individuals and the originating plant comprise a single genetic individual, i. e., a genet. The individual root sprouts are clones of the original plant, and each has a genome that is identical to that of the originating plant from which it grew. Many species of plants reproduce through vegetative reproduction, e. g. Canada thistle, cherry, apple, guava, privet, hazel, lilac, tree of heaven, and Asimina triloba.
The root sprout is a form of dispersal vector that allows plants to spread to habitats that favor their survival and growth. Some species, such as poplars and blackthorn, produce root sprouts that can spread rapidly, and they can form thick mats of roots that can reclaim areas that have been cleared of vegetation by logging, erosion, pasturing. The giant aspen, "Pando" is a dramatic example. These plants could be considered invasive, but they are cultivated or permitted to grow to stabilize soils and even to then be naturally replaced by non-pioneer species in locations as such those that have been developed for public works and along channels of waterways that may flood and reservoirs. These plants form shaded areas wherein new species may grow and gradually replace them.
Stolons are stems that grow on the surface of the soil or immediately below it and form adventitious roots at their nodes, and new clonal plants from the buds. Not all horizontal plant stems are stolons. Plants with stolons are described as "stoloniferous". Stolons, especially those above the surface of the soil are often denominated "runners". Rhizomes, in contrast, are root-like stems that may either grow horizontally on the surface of the soil or in other orientations underground.
In horticulture
Root sprouts and basal shoots can be used to propagate woody plants. Root sprouts can be dug or severed with some of the roots still attached. As for basal shoots, stool beds involve cutting a juvenile plant proximate to the surface of the soil and heaping soil over the cut so that basal shoots will form adventitious roots and later can be severed to form multiple, rooted, new plants. The technique is used especially for vegetative propagation of rootstocks for apple trees.
References
Horticulture
Plant morphology | Basal shoot | [
"Biology"
] | 836 | [
"Plant morphology",
"Plants"
] |
5,552,846 | https://en.wikipedia.org/wiki/Leaning%20toothpick%20syndrome | In computer programming, leaning toothpick syndrome (LTS) is the situation in which a quoted expression becomes unreadable because it contains a large number of escape characters, usually backslashes ("\"), to avoid delimiter collision.
The official Perl documentation introduced the term to wider usage; there, the phrase is used to describe regular expressions that match Unix-style paths, in which the elements are separated by slashes /. The slash is also used as the default regular expression delimiter, so to be used literally in the expression, it must be escaped with a backslash \, leading to frequent escaped slashes represented as \/. If doubled, as in URLs, this yields \/\/ for an escaped //. A similar phenomenon occurs for DOS/Windows paths, where the backslash is used as a path separator, requiring a doubled backslash \\ – this can then be re-escaped for a regular expression inside an escaped string, requiring \\\\ to match a single backslash. In extreme cases, such as a regular expression in an escaped string, matching a Uniform Naming Convention path (which begins \\) requires 8 backslashes \\\\\\\\ due to 2 backslashes each being double-escaped.
LTS appears in many programming languages and in many situations, including in patterns that match Uniform Resource Identifiers (URIs) and in programs that output quoted text. Many quines fall into the latter category.
Pattern example
Consider the following Perl regular expression intended to match URIs that identify files under the pub directory of an FTP site:
m/ftp:\/\/[^\/]*\/pub\//
Perl, like sed before it, solves this problem by allowing many other characters to be delimiters for a regular expression. For example, the following three examples are equivalent to the expression given above:
m{ftp://[^/]*/pub/}
m#ftp://[^/]*/pub/#
m!ftp://[^/]*/pub/!
Or this common translation to convert backslashes to forward slashes:
tr/\\/\//
may be easier to understand when written like this:
tr{\\}{/}
Quoted-text example
A Perl program to print an HTML link tag, where the URL and link text are stored in variables $url and $text respectively, might look like this. Notice the use of backslashes to escape the quoted double-quote characters:
print "<a href=\"$url\">$text</a>";
Using single quotes to delimit the string is not feasible, as Perl does not expand variables inside single-quoted strings. The code below, for example, would not work as intended:
print '<a href="$url">$text</a>'
Using the printf function is a viable solution in many languages (Perl, C, PHP):
printf('<a href="%s">%s</a>', $url, $text);
The qq operator in Perl allows for any delimiter:
print qq{<a href="$url">$text</a>};
print qq|<a href="$url">$text</a>|;
print qq(<a href="$url">$text</a>);
Here documents are especially well suited for multi-line strings; however, Perl here documents hadn't allowed for proper indentation before v5.26. This example shows the Perl syntax:
print <<HERE_IT_ENDS;
<a href="$url">$text</a>
HERE_IT_ENDS
Other languages
C#
The C# programming language handles LTS by the use of the @ symbol at the start of string literals, before the initial quotation marks, e.g.
string filePath = @"C:\Foo\Bar.txt";
rather than otherwise requiring:
string filePath = "C:\\Foo\\Bar.txt";
C++
The C++11 standard adds raw strings:
std::string filePath = R"(C:\Foo\Bar.txt)";
If the string contains the characters )", an optional delimiter can be used, such as d in the following example:
std::regex re{ R"d(s/"\([^"]*\)"/'\1'/g)d" };
Go
Go indicates that a string is raw by using the backtick as a delimiter:
s := `C:\Foo\Bar.txt`
Raw strings may contain any character except backticks; there is no escape code for a backtick in a raw string. Raw strings may also span multiple lines, as in this example, where the strings s and t are equivalent:
s := `A string that
spans multiple
lines.`
t := "A string that\nspans multiple\nlines."
Python
Python has a similar construct using r:
filePath = r"C:\Foo\Bar.txt"
One can also use them together with triple quotes:
example = r"""First line : "C:\Foo\Bar.txt"
Second line : nothing"""
R
R has a similar construct using r or R with various bracket deliminators ((, [, {):
filePath <- r"(C:\Foo\Bar.txt)"
For raw strings that contain ( instances
string <- r"{Text with (some) parentheses}"
For additional flexibility, a number of dashes can be placed between the opening quote and the opening delimiter, as long as the same number of dashes appear between the closing delimiter and the closing quote.
Ruby
Ruby uses single quote to indicate raw string:
filePath = 'C:\Foo\Bar.txt'
It also has regex percent literals with choice of delimiter like Perl:
%r{ftp://[^/]*/pub/}
%r#ftp://[^/]*/pub/#
%r!ftp://[^/]*/pub/!
Rust
Rust uses a variant of the r prefix:
"\x52"; // R
r"\x52"; // \x52
r#""foo""#; // "foo"
r##"foo #"# bar"##; // foo #"# bar
The literal starts with r followed by any number of #, followed by one ". Further " contained in the literal are considered part of the literal, unless followed by at least as many # as used after the opening r. As such, a string literal opened with r#" cannot have "# in its content.
Scala
Scala allows usage of triple quotes in order to prevent escaping confusion:
val filePath = """C:\Foo\Bar.txt"""
val pubPattern = """ftp://[^/]*/pub/"""r
The triple quotes also allow for multiline strings, as shown here:
val text = """First line,
second line."""
Sed
Sed regular expressions, particularly those using the "s" operator, are much similar to Perl (sed is a predecessor to Perl). The default delimiter is "/", but any delimiter can be used; the default is , but is also a valid form. For example, to match a "pub" directory (as in the Perl example) and replace it with "foo", the default (escaping the slashes) is
s/ftp:\/\/[^\/]*\/pub\//foo/
Using an exclamation point ("!") as delimiter instead yields
s!ftp://[^/]*/pub/!foo!
See also
Magic quotes
String literal
References
Software engineering folklore
Perl
PHP
Articles with example Perl code
Regular expressions
Articles with example Python (programming language) code | Leaning toothpick syndrome | [
"Engineering"
] | 1,784 | [
"Software engineering",
"Software engineering folklore"
] |
5,553,880 | https://en.wikipedia.org/wiki/XTX | XTX is a computer-on-module (COM) standard for x86-based embedded devices. XTX adds PCI-Express, SATA, and LPC capabilities. The standard was promulgated by Advantech Corporation, Ampro, and Congatec.
References
External links
"Next-gen computer module standard gains momentum" on LinuxDevices.com
Supplier of Extreme Rugged and Industrial XTX products
Motherboard form factors
Computer standards | XTX | [
"Technology"
] | 96 | [
"Computing stubs",
"Computer standards",
"Computer hardware stubs"
] |
5,554,551 | https://en.wikipedia.org/wiki/Soil-plant-atmosphere%20continuum | The soil-plant-atmosphere continuum (SPAC) is the pathway for water moving from soil through plants to the atmosphere. Continuum in the description highlights the continuous nature of water connection through the pathway. The low water potential of the atmosphere, and relatively higher (i.e. less negative) water potential inside leaves, leads to a diffusion gradient across the stomatal pores of leaves, drawing water out of the leaves as vapour. As water vapour transpires out of the leaf, further water molecules evaporate off the surface of mesophyll cells to replace the lost molecules since water in the air inside leaves is maintained at saturation vapour pressure. Water lost at the surface of cells is replaced by water from the xylem, which due to the cohesion-tension properties of water in the xylem of plants pulls additional water molecules through the xylem from the roots toward the leaf.
Components
The transport of water along this pathway occurs in components, variously defined among scientific disciplines:
Soil physics characterizes water in soil in terms of tension,
Physiology of plants and animals characterizes water in organisms in terms of diffusion pressure deficit, and
Meteorology uses vapour pressure or relative humidity to characterize atmospheric water.
SPAC integrates these components and is defined as a:
...concept recognising that the field with all its components (soil, plant, animals and the ambient atmosphere taken together) constitutes a physically integrated, dynamic system in which the various flow processes involving energy and matter occur simultaneously and independently like links in the chain.
This characterises the state of water in different components of the SPAC as expressions of the energy level or water potential of each. Modelling of water transport between components relies on SPAC, as do studies of water potential gradients between segments.
See also
Ecohydrology
Evapotranspiration
Hydraulic redistribution; a parameter now being considered in the soil-plant-atmosphere modeling community
Transpiration stream
References
Climatology
Ecological processes
Hydrology
Soil physics
Water and the environment
Plant physiology | Soil-plant-atmosphere continuum | [
"Physics",
"Chemistry",
"Engineering",
"Biology",
"Environmental_science"
] | 416 | [
"Plant physiology",
"Physical phenomena",
"Earth phenomena",
"Applied and interdisciplinary physics",
"Hydrology",
"Plants",
"Soil physics",
"Ecological processes",
"Environmental engineering"
] |
5,554,712 | https://en.wikipedia.org/wiki/Optimum%20water%20content%20for%20tillage | The optimum water content for tillage (OPT) is defined as the moisture content of soil at which tillage produces the largest number of small aggregates.
Overview
The Optimum Water Content of soil is the water content at which a maximum dry unit weight can be achieved after a given compaction effort. A max dry unit weight would have no voids in the soil. If you were trying to compact a hard dry soil to make it more dense, you might want to get it wet. The OPT is the water content of the soil in which you could compact it the most. If there is too much water you would have too much pore water pressure during compression to compact any further. If there is too little water the soil would naturally resist compaction via shear strength/friction/effective stress. The determination of the OPT is important because if tillage is carried out on fields that are wetter or drier than the OPT many problems can be caused, including soil structural damage, through the production of large clods, and an increase in the content of readily dispersible clay which is indicative of the soil stability.
The OPT can be determined in relation to the volumetric water content at the lower Plastic Limit of the soil (PL).
Some examples of suggested OPT:
On a lateritic sandy loam : 0.77 PL
On a sandy loam : 0.9 PL
For several soils the OPT has been found to equal 0.9 PL, although there are a number of limitations with the use of the lower plastic limit in determining the optimal moisture content. Firstly it is a property of a moulded soil and not an undisturbed soil in the field and secondly, many sandy soils are not plastic and do not have a lower plastic limit.
Relationships between water content at field capacity (FC) and Plastic Limit(PL)
When FC < PL
Soil will drain to a water content at which no excessive structural damage will occur on tillage.
When FC > PL
Soil will never drain to a water content ideal for tillage
Many clay soils drain very slowly, and as a result they are usually wetter than PL unless they are dried by water extraction by plant uptake.
Soil friability
Soil friability is the tendency of a mass of soil to crumble under the action of an applied force. This has been found to be maximum at the PL of a soil.
See also
Field capacity
Plastic limit
References
Soil physics | Optimum water content for tillage | [
"Physics"
] | 492 | [
"Applied and interdisciplinary physics",
"Soil physics"
] |
5,554,858 | https://en.wikipedia.org/wiki/Runoff%20curve%20number | The runoff curve number (also called a curve number or simply CN) is an empirical parameter used in hydrology for predicting direct runoff or infiltration from rainfall excess. The curve number method was developed by the USDA Natural Resources Conservation Service, which was formerly called the Soil Conservation Service or SCS — the number is still popularly known as a "SCS runoff curve number" in the literature. The runoff curve number was developed from an empirical analysis of runoff from small catchments and hillslope plots monitored by the USDA. It is widely used and is an efficient method for determining the approximate amount of direct runoff from a rainfall event in a particular area.
Definition
The runoff curve number is based on the area's hydrologic soil group, land use, treatment and hydrologic condition. References, such as from USDA indicate the runoff curve numbers for characteristic land cover descriptions and a hydrologic soil group.
The runoff equation is:
where
is runoff ([L]; in)
is rainfall ([L]; in)
is the potential maximum soil moisture retention after runoff begins ([L]; in)
is the initial abstraction ([L]; in), or the amount of water before runoff, such as infiltration, or rainfall interception by vegetation; historically, it has generally been assumed that , although more recent research has found that may be a more appropriate relationship in urbanized watersheds where the CN is updated to reflect developed conditions.
The runoff curve number, , is then related
has a range from 30 to 100; lower numbers indicate low runoff potential while larger numbers are for increasing runoff potential. The lower the curve number, the more permeable the soil is. As can be seen in the curve number equation, runoff cannot begin until the initial abstraction has been met. It is important to note that the curve number methodology is an event-based calculation, and should not be used for a single annual rainfall value, as this will incorrectly miss the effects of antecedent moisture and the necessity of an initial abstraction threshold.
Selection
The NRCS curve number is related to soil type, soil infiltration capability, land use, and the depth of the seasonal high water table. To account for different soils' ability to infiltrate, NRCS has divided soils into four hydrologic soil groups (HSGs). They are defined as follows.
HSG Group A (low runoff potential): Soils with high infiltration rates even when thoroughly wetted. These consist chiefly of deep, well-drained sands and gravels. These soils have a high rate of water transmission (final infiltration rate greater than per hour).
HSG Group B: Soils with moderate infiltration rates when thoroughly wetted. These consist chiefly of soils that are moderately deep to deep, moderately well drained to well drained with moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission (final infiltration rate of per hour).
HSG Group C: Soils with slow infiltration rates when thoroughly wetted. These consist chiefly of soils with a layer that impedes downward movement of water or soils with moderately fine to fine textures. These soils have a slow rate of water transmission (final infiltration rate per hour).
HSG Group D (high runoff potential): Soils with very slow infiltration rates when thoroughly wetted. These consist chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a claypan or clay layer at or near the surface, and shallow soils over nearly impervious materials. These soils have a very slow rate of water transmission (final infiltration rate less than per hour).
Selection of a hydrologic soil group should be done based on measured infiltration rates, soil survey (such as the NRCS Web Soil Survey), or judgement from a qualified soil science or geotechnical professional. The table below presents curve numbers for antecedent soil moisture condition II (average moisture condition). To alter the curve number based on moisture condition or other parameters, see Adjustments.
Values
Adjustments
Runoff is affected by the soil moisture before a precipitation event, the antecedent moisture condition (AMC). A curve number, as calculated above, may also be termed AMC II or , or average soil moisture. The other moisture conditions are dry, AMC I or , and moist, AMC III or . The curve number can be adjusted by factors to , where factors are less than 1 (reduce and potential runoff), while factor are greater than 1 (increase and potential runoff). The AMC factors can be looked up in the reference table below. Find the CN value for AMC II and multiply it by the adjustment factor based on the actual AMC to determine the adjusted curve number.
Initial abstraction ratio adjustment
The relationship was derived from the study of many small, experimental watersheds . Since the history and documentation of this relationship are relatively obscure, more recent analysis used model fitting methods to determine the ratio of to with hundreds of rainfall-runoff data from numerous U.S. watersheds. In the model fitting done by Hawkins et al. (2002) found that the ratio of to varies from storm to storm and watershed to watershed and that the assumption of is usually high. More than 90 percent of ratios were less than 0.2. Based on this study, use of ratios of 0.05 rather than the commonly used value of 0.20 would seem more appropriate. Thus, the CN runoff equation becomes:
In this equation, note that the values of are not the same as the one used in estimating direct runoff with an ratio of 0.20, because 5 percent of the storage is assumed to be the initial abstraction, not 20 percent. The relationship between and was obtained from model fitting results, giving the relationship:
The user, then, must do the following to use the adjusted 0.05 initial abstraction ratio:
Use the traditional tables of curve numbers to select the value appropriate for your watershed.
Calculate using the traditional equation:
Convert this S value to using the relationship above.
Calculate the runoff depth using the CN runoff equation above (with 0.05 substituted for the initial abstraction ratio).
See also
HydroCAD a software tool for H&H modeling
Hydrological modelling
Runoff model (reservoir)
Recharge (hydrology)
References
External links
SCS TR-55 Peak Discharge and Runoff Calculator
Curve Number Calculator Online Free Curve Number Calculator
Introduction to SCS Runoff Curve Number Method
Hydrology
Soil physics | Runoff curve number | [
"Physics",
"Chemistry",
"Engineering",
"Environmental_science"
] | 1,303 | [
"Environmental engineering",
"Hydrology",
"Applied and interdisciplinary physics",
"Soil physics"
] |
5,555,202 | https://en.wikipedia.org/wiki/Automatic%20transmission%20fluid | Automatic transmission fluid (ATF) is a hydraulic fluid that is essential for the proper functioning of vehicles equipped with automatic transmissions. Usually, it is coloured red or green to differentiate it from motor oil and other fluids in the vehicle.
This fluid is designed to meet the unique demands of an automatic transmission. It is formulated to ensure smooth valve operation, minimize brake band friction, facilitate torque converter function, and provide effective gear lubrication.
ATF is commonly utilized as a hydraulic fluid in certain power steering systems, as a lubricant in select 4WD transfer cases, and in modern manual transmissions.
Modern use
Modern ATF consists of a base oil and an additive package that contains a wide variety of chemical compounds intended to provide the required properties of a particular ATF specification. Most ATFs contain some combination of additives that improve lubricating qualities, such as anti-wear additives, rust and corrosion inhibitors, detergents, dispersants and surfactants (which protect and clean metal surfaces); kinematic viscosity and viscosity index improvers and modifiers, seal swell additives and agents (which extend the rotational speed range and temperature range of the additives' application); anti-foam additives and anti-oxidation compounds to inhibit oxidation and "boil-off" (which extends the life of the additives' application); cold-flow improvers, high-temperature thickeners, gasket conditioners, pour point depressant and petroleum dye. All ATFs contain friction modifiers, except for those ATFs specified for some Ford transmissions and the John Deere J-21A specification; the Ford ESP (or ESW) - M2C-33 F specification Type F ATF (Ford-O-Matic) and Ford ESP (or ESW) - M2C-33 G specification Type G ATF (1980s Ford Europe and Japan) specifically excludes the addition of friction modifiers. According to the same oil distributor, the M2C-33 G specification requires fluids which provide improved shear resistance and oxidation protection, better low-temperature fluidity, better EP (extreme pressure) properties and additional seal tests over and above M2C-33 F quality fluids.
The friction modifier means that the fluid sticks to the surface of the metal slightly stronger, and therefore only helps to prevent early wear. It would be required for Ford and BorgWarner to prove that their transmissions are somehow harmed by friction modifiers. In many countries, Ford has said that the modern Dex3 fluid is fine for the same transmissions that it says require the older standard.
There are many specifications for ATF, such as the General Motors (GM) DEXRON and the Ford MERCON series, and the vehicle manufacturer will identify the ATF specification appropriate for each vehicle. The vehicle's owner's manual will typically list the ATF specification(s) that are recommended by the manufacturer.
Automatic transmission fluids have many performance-enhancing chemicals added to the fluid to meet the demands of each transmission. Some ATF specifications are open to competing brands, such as the common DEXRON specification, where different manufacturers use different chemicals to meet the same performance specification. These products are sold under license from the OEM responsible for establishing the specification. Some vehicle manufacturers will require "genuine" or Original Equipment Manufacturer (OEM) ATF. Most ATF formulations are open 3rd party licensing and certification by the automobile manufacturer.
Current fluids
DEXRON ULV - 2017 and above GM 10L90 10-speed automatic transmissions
MERCON ULV - 2017 and above Ford 10R80 10-speed automatic transmissions
DEXRON HP - 2013 and above GM 8L90 8-speed RWD automatic transmissions
Mopar ATF+4 - Most Dodge, Jeep, Chrysler, and Plymouth replaces ATF+3, ATF+2, ATF+
DEXRON III/MERCON - Most pre-2006 GM and Ford, Mercury, Lincoln, pre-2004 Toyota products, many Asian vehicles, some Asian power steering fluid applications, some Ford/Mazda manual transmissions. It is generally less expensive than DEXRON VI/MERCON V .
DEXRON VI - Most after 2006 GM, some Ford applications, replaces DEXRON III in GM automatic transmissions.
MERCON V - Most Ford, Mercury, Lincoln, Mazda B-Series, 2001-08 Mazda Tribute, Tribute Hybrid.
MERCON LV - Some Ford(DuratecHE), 2009-11 Mazda Tribute, Mazda in Europe or Asia.
Mercon SP - For the Ford 6R transmission
Toyota ATF Type T-IV (T4) - Some older Toyota, Lexus including "Gen 1" hybrid CVT), some Mazda. Replaces Type T, and Type T-II (There was no Type T-III).
Toyota ATF WS - Most new models introduced with model year 2004 Toyota and Lexus including "Gen 2" and later hybrid CVT (except non-hybrid CVT); Volvo. It is not applicable in applications requiring ATF Type T-IV.
Honda DW-1 - All Honda and Acura (except continuously variable transmission (CVT)), replaces Z1 specification fluid.
Diamond SP-III (or SP3) - Older Mitsubishi Motors (including older CVTs; Hyundai and Kia 4-speed automatic transmission.
Diamond SP-IV (or SP4) - All Hyundai and Kia 6-speed automatic transmission.
DiaQueen ATF-J3 - Most Mitsubishi Motors 6-speed automatic transmissions.
Nissan Matic fluids - For Nissan and Infiniti vehicles:
Matic D is for 3- and 4-speed transmissions,
Matic K is for 6-speed front-wheel-drive transmissions,
Matic J is for 5-speed rear-wheel-drive transmissions,
Matic-S fluid supersedes Matic-J fluid.
ATF-HP - For 2005 and later Subaru vehicles, except CVTs. 2004 and earlier Subaru vehicles use DEXRON III.
Mazda M5 (MV) fluid - For the Mazda FN4A-EL/Ford 4F27E and Mazda FS5A-EL/Ford FNR5. Also sold as Ford FNR5 fluid. Genuine Mazda M5 is made by Idemitsu Kosan, available as Idemitsu Type-M. This fluid is NOT MERCON V.
Mazda FZ fluid - For the SKYACTIV-Drive. The color of this fluid is blue.
Synthetic ATF is available in modern OEM and aftermarket brands, offering better performance and service life for certain applications (such as frequent trailer towing).
Using a lint-free white rag to wipe the dipstick on automatic transmissions is advised so that the color of the fluid can be checked. Dark brown or black ATF can be an indicator of a transmission problem, vehicle abuse, or fluid that has far exceeded its useful life. Overused ATF often has reduced lubrication properties and abrasive friction materials (from clutches and brake bands) suspended in it; failure to replace such fluid will accelerate transmission wear and could eventually ruin an otherwise healthy transmission. However, color alone is not a completely reliable indication of the service life of ATF, as most ATF products will darken with use. The manufacturer's recommended service interval is a more reliable measure of ATF life. In the absence of service or repair records, fluid color is a common means of gauging ATF service life.
CVTs and dual-clutch transmissions often use specialized fluids. Transfer cases and differentials in four-wheel-drive/all-wheel-drive vehicles sometimes require specialized fluids, such as Honda Dual Pump-II, Honda VTM-4, and Jeep Quadra-Trac.
History
The history of automatic transmission fluids parallels the history of automatic transmission technology. The world's first mass-produced automatic transmission, the Hydra-Matic 4-speed, was developed by General Motors (GM) for the 1940 model year. The Hydra-Matic transmission required a special lubricant GM called Transmission Fluid No. 1. for the Hydra-Matic Drive. This transmission fluid was only available at Oldsmobile, Pontiac, and Cadillac dealerships. As technology advanced and OEMs demanded longer-lasting and higher-quality automatic transmissions, so too did automatic transmission fluids advance.
In 1949, GM released a new Type "A" fluid specification. In an attempt to make GM automatic transmission fluid available at retailers and service garages everywhere. Every automatic transmission produced by any vehicle manufacturer used GM Type "A" transmission fluids in their transmissions from 1949-1958.
In 1959, Ford began releasing their own automatic transmission fluid specifications; see MERCON for more information. From 1958-1968 many vehicle manufacturers continued to use the next GM automatic transmission fluid specification, the Type "A" Suffix "A" fluid, in their transmissions. In 1966, Chrysler began releasing their own automatic transmission fluid specifications; see Mopar ATF for more information. GM ATF was the same color as engine oil through 1967. Aftermarket ATF was available with red dye as an aid in fluid leak detection. Dexron (B) was the first GM ATF to require red dye.
From the 1940s through the early 1970s, ATF contained whale oil as a rust and corrosion inhibitor. A moratorium on whale oil at that time prevented the continued production of older ATF such as the original 1967 DEXRON formulation (Type B), and the fluids which preceded it. Vintage GM (1940-1967), Ford (1951-1967, and Chrysler products (1953-1966) used GM Type A fluid or GM Type A Suffix A fluids; these fluids are no longer produced. GM recommends Dexron-VI fluid, Ford recommends Mercon V fluid, and Chrysler recommends ATF+4 fluids for vintage transmission use.
Through the late 1970s, Ford transmissions were factory-filled with a fluid identified as ESW M2C33-F. To provide a fluid that would be available to the general public for service fill, oil companies and other factory fill suppliers were allowed to develop fluids meeting the ESW M2C33-F specification and market these fluids under their brand names but identified as Type F.
The second generation of transmission fluid was released in 1974 as the factory fill specification, ESW M2C138-CJ. This fluid was developed to modify the vehicle shifting characteristics and to provide considerable improvement in the oxidation resistance and anti-wear performance.
No service fluids were developed and for a short time, DEXRON fluids approved by General Motors were considered acceptable. With continuing changes and improvements in transmission design, a centrifugal lock-up torque converter clutch was introduced into the C5 transmission to smooth engine vibrations sensed by the occupant of the vehicle. An associated shudder problem forced the introduction of the factory fill specification ESP M2C166-H. Servicing transmissions with DEXRON fluids was unacceptable since not all DEXRON fluids were capable of eliminating the shudder phenomenon. The fluids that could be used were a subset of the DEXRON fluids. The advent of Type H as factory fill necessitated the development of a service fluid specification to match the performance expected from Type H. This resulted in the release of the MERCON specification in 1987.
One major revision occurred in September 1992, when low-temperature viscosity requirements, volatility requirements, viscosity change limits after high-temperature exposure and improved oxidation limits were introduced. These changes raised the performance of MERCON fluids above ESP M2C166-H levels.
The development of modulating and continuous slipping clutch converters has prompted the need to develop the MERCON V specification. Included are requirements to verify the anti-wear capabilities and anti-shudder characteristics of the fluid.
The MERCON V specification was further modified sometime before 2007 to make it backwards-compatible with MERCON. Ford has/is terminating all license agreements for the manufacture and sale of MERCON in favor of MERCON V.
Toyota continued using GM ATF, including Dexron (B) and Dexron-II(D) in most of their automatic transmissions until 2003. In 1988, Toyota began releasing its own automatic transmission fluid specifications, see Toyota ATF for more information.
"Lifetime" fluids
In 1967, Ford produced the Type-F fluid specification. The Type-F specification was intended to produce a "lifetime" fluid which would never need to be changed. This was the first of many Ford "lifetime" fluids. The 1974 Ford Car Shop Manual reads "The automatic transmission is filled at the factory with "lifetime" fluid. If it is necessary to add or replace fluid, use only fluids which meet Ford Specification M2C33F. Many other transmission manufacturers have followed with their own "Lifetime" automatic transmission fluids".
How ATF Can Last a "Lifetime"
To understand how a fluid can last a "lifetime", a study of the 1939 Chrysler Fluid Drive Fluid is helpful. The lesson learned by Chrysler with its fluid drives applies to modern automatic transmissions as well. The November 1954 edition of Lubrication Magazine (Published by The Texas Company, later known as Texaco) featured a story called "Evolution of the Chrysler PowerFlite Automatic Transmission." This article described the fluid used in the 1939 Chrysler Fluid Drive and its subsequent revisions and enhancements through 1954. The fluid drive fluid coupling is partially filled with Mopar Fluid Drive Fluid, a special highly refined straight mineral oil with a viscosity of about 185 SUS at 100°F., excellent inherent oxidation stability, high viscosity index (100), excellent ability to rapidly reject air, very low natural pour point (-25°F.), ability to adequately lubricate the pilot ball bearing and seal surface, and neutrality towards the seal bellows.
The fluid operates under almost ideal conditions in what is essentially a hermetically sealed case; the small amount of atmospheric oxygen initially present is removed by a harmless reaction with the fluid to leave a residual inert (nitrogen) atmosphere. As a consequence, it has not been necessary to drain and replace the fluid, and the level-check recommendation has been successively extended from the original 2,500 miles to 15,500 miles and finally to "never" - or the life of the car.
Since drains and level checks were not only unnecessary but frequently harmful (through the introduction of more air, and seal-destroying dirt), Chrysler eventually left off the tempting level inspection plugs. This mechanism is, therefore, one of the very few that are lubricated for the life of the car. There are now myriad examples of couplings that have operated well over 100,000 miles without any attention whatsoever and were still in perfect condition when the car was retired.
On European-type cars, a "Lifetime" means 180,000 km or 112,000 miles as the lifetime of a vehicle or transmission. Service intervals of newer type cars are from 80,000 to 120,000 km which equals 50,000 to 75,000 miles. Flushing or refilling the fluid on lifetime-filled transmissions requires the use of equipment to fill from below, engaging the transmission torque converter or using an external pump.
Sealed Transmissions
Any automatic transmission fluid will last longer if the transmission case can be hermetically sealed, but transmissions typically have two potential entry points for air:
The Dipstick Tube. Any transmission with a dipstick tube has the potential to let additional oxygen into the transmission through a dipstick that is not fully seated in the tube or a dipstick tube plug that is not fully seated. Even the process of checking the fluid level with a dipstick can allow additional oxygen and dirt to be transmitted. Many modern transmissions do not have a dipstick. They have sealed transmission fluid level check plugs instead. By removing the traditional dipstick, the transmission manufacturer has also removed a potential entry point for oxygen; this reduces the potential for fluid oxidation. A sealed transmission will typically have a longer transmission fluid life than a non-sealed transmission.
The Transmission Vent. Transmissions need vents to compensate for internal air pressure changes that occur with fluctuating fluid temperatures and fluctuating fluid levels during transmission operation. Without those vents, pressure could build resulting in seal and gasket leaks. Before the use of better quality base oil in ATF in the late 1990s, some older transmission breather vents contained a Transmission Air Breathing Suppressor (TABS) valve to prevent oxygen and water ingestion into their transmissions. Oxygen reacts with high-temperature transmission fluid and can cause oxidation, rust, and corrosion. Automatic transmission fluids using lower quality base oil oxidized more easily than fluids using higher quality base oils. Transmission manufacturers now use smaller, remote mounted, breather vents specially designed to keep out water, but allow a small amount of air movement through the breather as necessary.
Sealed ATF Containers
Any automatic transmission fluid will last longer if it comes from an unopened container. Experts advise that containers storing automatic transmission fluid (ATF) be sealed; if exposed to the atmosphere, ATF may absorb moisture and potentially cause shift concerns. Experts have also advised that, when performing repairs on ATF-equipped transmissions, fresh ATF be used when refilling the transmission, and have warned not to reuse ATF.
Example Maintenance Schedule
Lifetime automatic transmission fluids made from higher-quality base oil and an additive package are more chemically stable, less reactive, and do not experience oxidation as easily as lower-quality fluids made from lower-quality base oil and an additive package. Therefore, higher-quality transmission fluids can last a long time in normal driving conditions (Typically 100,000 miles (160,000 km) or more).
The definition of 'Lifetime Fluid" differs from transmission manufacturer to transmission manufacturer. Always consult the vehicle maintenance guide for the proper service interval for the fluid in your transmission and your driving conditions.
Chevrolet Colorado Example: According to the Scheduled Maintenance Guide a 2018 Chevrolet Colorado with "Lifetime Fluid" could have two different fluid service intervals depending upon how the vehicle is driven:
1. Normal Driving
Carry passengers and cargo within recommended limits on the Tire and Loading Information label
Driven on reasonable road surfaces within legal driving limits.
2. Severe Driving
Mainly driven in heavy city traffic in hot weather
Mainly driven in hilly or mountainous terrain
Frequently towing a trailer
Used for high-speed or competitive driving
Used for taxi, police, or delivery service.
Under "Severe" driving conditions, replace automatic transmission fluid and filter every 45,000 mi (72,420 km)
Aftermarket Automatic Transmission Fluids
For over 70 years, the oil aftermarket has produced both licensed and non-licensed, formulations of automatic transmission fluids (ATF). Today, aftermarket fluids asserted by their manufacturers to be compatible for use in various brands of automatic transmissions continue to be sold under names such as Multi-Purpose and Multi-Vehicle fluids. Non-licensed fluids are typically less expensive; these fluids are not regulated or endorsed by the vehicle manufacturer for use in their transmissions. Vehicle manufacturer-approved and licensed fluids must have the license number printed on the product information label of the container or the container housing. Non-licensed fluids do not show a license number. Make sure the fluid to be installed into a transmission matches the recommended fluid in the specifications section of the vehicle's owner's manual.
Note that: If your vehicle is still under warranty, you should only use OEM fluids. Otherwise, your dealer might void it.
Mislabeled or Misleading Labeling on ATF Containers
ATF which has been mislabeled, has misleading labeling, or is fraudulently bottled as another product is an ongoing problem. Some of these fluids have led to multiple transmission failures. The three organizations shown below are trying to stop this problem in the United States.
United States Laws: The U.S. Department of Commerce, National Institute of Standards and Technology (NIST), Handbook 130 2019 Edition, contains Uniform Laws and Regulations in the Areas of Legal Metrology and Fuel Quality. Section IV.G.3.14 defines laws regulating the Labeling and Identification of Transmission Fluid. Paragraph IV.G.3.14.1.1. Container Labeling. reads The label on a container of transmission fluid shall not contain any information that is false or misleading.
California Laws: The State of California has developed additional Laws in an attempt to prevent mislabeled and misleading labelling. Statutes: California Business and Professions Code, Division 5, Chapters 6, 14, 14.5, and 15. Regulations: California Code of Regulation, Title 4, Division 9, Chapters 6 and 7.
American Petroleum Institute (API) Monitoring: The American Petroleum Institute (API) maintains a list of invalid labelling of petroleum products. This real-time list includes motor oils and ATF.
See also
GM DEXRON automatic transmission fluids
Ford MERCON automatic transmission fluids
References
External links
A Look at Changes in Automatic Transmission Fluid
The History of Automatic Transmission Fluid - ATF History Part 1
Changing Gears: The Development of the Automotive Transmission
World's First Mass Produced Automatic Transmission - Part 1- Introduction and History
Automotive chemicals
Automobile transmissions
Petroleum based lubricants
Oils | Automatic transmission fluid | [
"Chemistry"
] | 4,289 | [
"Oils",
"Carbohydrates"
] |
5,555,347 | https://en.wikipedia.org/wiki/John%20W.%20Powell | John William Powell (July 3, 1919 – December 15, 2008) was a journalist and small business proprietor who edited the China Weekly Review, an English-language journal first published by his father, John B. Powell in Shanghai.
John W. Powell was tried for sedition in 1959 after publishing an article that reported on allegations made by Mainland Chinese officials that the United States and Japan were carrying out germ warfare in the Korean War. In 1956, the Eisenhower Administration's Department of Justice pressed sedition charges against Powell, his wife Sylvia, and Julian Schuman, after federal prosecutors secured grand jury indictments against them for publishing allegations of bacteriological warfare. However, the prosecutors failed to get any convictions. The defendants invoked their Constitutional right to refuse to reveal self-incriminating evidence, and U.S. Department of Defense officials also refused to provide any incriminating archives or witnesses. This information was not revealed until decades later as a result of Freedom of Information Act requests.
All three of the defendants were acquitted of all charges over the next six years, after a Federal judge dismissed the core aspects of the case against them in 1959, due to obviously insufficient evidence against them.
Early life and career
Powell was born in Shanghai, China, in 1919. One year later, Powell's parents decided that Shanghai was unsafe for their infant, so they sent him to live with his mother's family in Hannibal, Missouri. In 1917, Powell's father, John Benjamin Powell, had been a co-founder of the tiny publication, the China Weekly Review (originally Thomas Franklin Fairfax Millard’s Review of the Far East, 1922 renamed Weekly Review of the Far East, 1923 renamed The China Weekly Review, retaining the Chinese heading Mìlè Pínglúnbào 《密勒評論報》, i.e. “Millard’s Review”), modeled after the influential American political journals The New Republic and The Nation, and which featured original reporting, reports on Chinese subjects, and editorials.
Interrupting his journalism studies at the University of Missouri, Powell rejoined his father at the China Weekly Review. After the Japanese Attack on Pearl Harbor, Powell joined the American Office of War Information, the military's journalism program, as a news editor. In 1943, Powell was sent to Chungking, China, a city in far southwestern China (and the wartime capital of Free China), where he remained for the rest of the war. For eight years after World War II, from 1945 until June, 1953, Powell published his journal, first as the "China Weekly Review" and later on, when its revenues declined greatly, as the "China Monthly Review". While in China, Powell was an advocate for Chinese sovereignty and was a supporter of Chinese president Cao Kun.
Sedition allegations
During the Red-baiting 1950s, the Federal government initially accused Powell and his wife of treason. On April 26, 1956, the Powells, along with an associate at the "China Monthly Review", learned that a Federal Grand Jury had indicted each of them on a charge of sedition. Each count in the indictment was punishable by up to twenty years in prison and up to $10,000 in fines. The most damaging charge was that the defendants had falsely reported that the United States had engaged in bacteriological warfare during the Korean War, and that North Koreans had forced American Prisoners of War to read published reports of these charges as part of their indoctrination processes and brainwashing.
In their coverage of the breaking news, the San Francisco Chronicle newspaper, among other news publications, used two-inch-high bold type on its front page, exclaiming "S.F. JURY INDICTS WRITER – SEDITION". The grand jury had charged Powell with a dozen counts of sedition and a count of conspiring to commit sedition. His wife, Sylvia and Julian Schuman, who had been Powell's associate editor, were also charged with a single count of conspiracy, each. The Powells responded to the charges by asserting they had properly reported on what was said by Chinese officials and troops coming from the front lines of the Korean War.
Powell's trial, which ended in a mistrial, took place in 1959 at the Federal Courthouse in San Francisco, the same location where Marie Equi had been tried and convicted of sedition in 1918. The treason charges against Powell were formally dismissed in July, 1959, and two years later, in 1961, Attorney General Robert F. Kennedy finally dropped the rest of the sedition charges.
Later developments
Although direct official evidence such as military records and similar documentation that bacteriological warfare was employed during the Korean War by either side does not exist, some contend that there is overwhelming indirect and unofficial evidence that the US used biological weapons during this war. In an effort to advocate his opinions about American involvement in bacteriological warfare in Asia, Powell published an article titled "Japan's Germ Warfare: The U.S. Cover-up of a War Crime" in the October/December, 1980, issue of the "Bulletin of Concerned Asian Scholars". An editor from the United Press International had told Powell his story was "old news," and it was not published by mainstream publications.
However, with the documents that he had obtained under the Freedom of Information Act, Powell was able to provide additional evidence supporting his earlier reports in the "China Monthly Review". The second article, "Japan's Biological Weapons, 1930-1945," was published in the October 1981 edition of The Bulletin of the Atomic Scientists. It wasn't until 1989 that a detailed account of the Japanese bacteriological warfare experiments in China appeared. The British journalists Peter Williams and David Wallace published their book, "Unit 731: Japan's Secret of Secrets" (London: Hodder and Stoughton). [Also published in New York City that same year as "Unit 731: Japan's Secret Biological Warfare in World War II"]. Even in the 21st Century, 60 years after the Japanese bacteriological warfare camps, American intelligence agencies and the Department of Defense still withhold certain information about the World War II Japanese program in China.
Powell's articles in The Bulletin of the Atomic Scientists eventually led to the broadcast of segments on the CBS-TV investigative news program 60 Minutes and ABC-TV's 20/20 program. Powell's reporting had brought widespread public attention to the use of bacteriological warfare, which helped prompt the United States Congress into hearing testimony from former American Prisoners of War in 1982 and 1986.
Personal life
Powell met his wife Sylvia Powell in 1947, while he was in Shanghai opening up a news bureau for the Office of War Information, and they were married soon afterwards.
After returning to the United States from China, the Powells bought an old house on Potrero Hill in San Francisco, undertook extensive repairs and renovations, and then sold it for a profit. They next settled into a pattern of buying, rehabilitating, and reselling fourteen houses and several apartment buildings. "It was kind of rough," John Powell said, "Obviously, I couldn't get a job on a newspaper. I tried various things, working as a salesman, selling teaching aids to schools."
Eventually, the Powells bought a house on Church Street, in San Francisco's Mission District, and lived there for thirty years. This house had a storefront where they also ran an antiques shop and remodeled Victorian homes for about fifteen years as a result of Powell being "blackballed" due to his alleged sedition..
Powell died on December 15, 2008, in San Francisco at the age of 89 as a result of complications from pneumonia.
See also
Allegations of biological warfare in the Korean War
References
Selected publications
A Plague Upon Humanity: The Secret Genocide of Axis Japan's Germ Warfare Operation, Daniel Barenblatt, New York: HarperCollins, 2004,
The United States and Biological Warfare: Secrets from the Early Cold War and Korea, Stephen Endicott and Edward Hagerman, Bloomington: Indiana University Press, 1998
Unit 731: The Japanese Army's Secret of Secrets, Peter Williams and David Wallace, London: Hodder and Stoughton, 1989. Also published in the United States in 1989 as: Unit 731: Japan's Secret Biological Warfare in World War II.
Further reading
"The American Inquisition: Justice and Injustice In The Cold War" Stanley I. Kutler, Hill & Wang, New York, 1982
French, Paul. Carl Crow: A Tough Old China Hand: The Life, Times, and Adventures of an American in Shanghai. Hong Kong University Press, 2007.
French, Paul. Through the Looking Glass: Foreign Journalists in China, from the Opium Wars to Mao. Hong Kong University Press, 2009.
Powell, John Benjamin. My Twenty-Five Years in China. New York: The Macmillan Co., 1945. Autobiography of John W. Powell's father, who lived in Shanghai 1917-1942 when interned by the Japanese.
External links
NewsReview.com - "Dirty secrets: The government tried to put journalist John W. Powell in prison half a century ago for reporting that the U.S. Army had used germ warfare in Korea. He's still convinced it's true." Robert Speer, Chico News & Review (July, 2006)
SFGate.com - "Sylvia Powell—writer accused, then cleared, of treason in 1950s" obituary for Powell's wife), Michael Taylor, San Francisco Chronicle (July 13, 2004)
1919 births
2008 deaths
Powell, John W.
Powell, John W.
American freelance journalists
American alternative journalists
American investigative journalists
People related to biological warfare
Powell, John W.
Mission District, San Francisco
Censorship in the United States
People of the United States Office of War Information
American expatriates in China | John W. Powell | [
"Biology"
] | 2,012 | [
"People related to biological warfare",
"Biological warfare"
] |
5,555,367 | https://en.wikipedia.org/wiki/GeoPublish | geoPublish is a discontinued desktop publishing program made by Berkeley Softworks for their GEOS Operating System.
geoPublish brought proper Desktop Publishing to the Commodore 64. With Left and Right Master Pages page layout work was simplified with the ability to work on the full page at once. Other features included autoflow text placement, the ability to create 16-page documents (with page numbering up to 256 to facilitate chaining documents), a suite of object-oriented drawing tools, and the ability to scale fonts from 4-192 points. geoPublish is capable of outputting PostScript page descriptions to laser printers and is used for creating posters, newsletters, and even books.
Versions
A version for the Commodore 64 was released in 1986. It was ported to the Apple II in 1988. Version 2.0 was released in 1993.
References
1986 software
Desktop publishing software
Commodore 64 software
Apple II software
Apple II word processors | GeoPublish | [
"Technology"
] | 189 | [
"Computing stubs",
"Digital typography stubs"
] |
5,556,198 | https://en.wikipedia.org/wiki/Trp%20operon | The trp operon''' is a group of genes that are transcribed together, encoding the enzymes that produce the amino acid tryptophan in bacteria. The trp operon was first characterized in Escherichia coli, and it has since been discovered in many other bacteria. The operon is regulated so that, when tryptophan is present in the environment, the genes for tryptophan synthesis are repressed.
The trp operon contains five structural genes: trpE, trpD, trpC, trpB, and trpA, which encode the enzymes needed to synthesize tryptophan. It also contains a repressive regulator gene called trpR. When tryptophan is present, the trpR protein binds to the operator, blocking transcription of the trp operon by RNA polymerase.
This operon is an example of repressible negative regulation of gene expression. The repressor protein binds to the operator in the presence of tryptophan (repressing transcription) and is released from the operon when tryptophan is absent (allowing transcription to proceed). The trp operon additionally uses attenuation to control expression of the operon, a second negative feedback control mechanism.
The trp operon is well-studied and is commonly used as an example of gene regulation in bacteria alongside the lac operon.
Genes trp operon contains five structural genes. The roles of their products are:
TrpE (): Anthranilate synthase produces anthranilate.
TrpD (): Cooperates with TrpE.
TrpC (): Phosphoribosylanthranilate isomerase domain first turns N-(5-phospho-β-D-ribosyl)anthranilate into 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose 5-phosphate. The Indole-3-glycerol-phosphate synthase on the same protein then turns the product into (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate.
TrpA (), TrpB (): two subunits of tryptophan synthetase. Combines TrpC's product with serine to produce tryptophan.
Repression
The operon operates by a negative repressible feedback mechanism. The repressor for the trp operon is produced upstream by the trpR gene, which is constitutively expressed at a low level. Synthesized trpR monomers associate into dimers. When tryptophan is present, these tryptophan repressor dimers bind to tryptophan, causing a change in the repressor conformation, allowing the repressor to bind to the operator. This prevents RNA polymerase from binding to and transcribing the operon, so tryptophan is not produced from its precursor. When tryptophan is not present, the repressor is in its inactive conformation and cannot bind the operator region, so transcription is not inhibited by the repressor.
Attenuation
Attenuation is a second mechanism of negative feedback in the trp operon. The repression system targets the intracellular trp concentration whereas the attenuation responds to the concentration of charged tRNAtrp. Thus, the trpR repressor decreases gene expression by altering the initiation of transcription, while attenuation does so by altering the process of transcription that's already in progress. While the TrpR repressor decreases transcription by a factor of 70, attenuation can further decrease it by a factor of 10, thus allowing accumulated repression of about 700-fold. Attenuation is made possible by the fact that in prokaryotes (which have no nucleus), the ribosomes begin translating the mRNA while RNA polymerase is still transcribing the DNA sequence. This allows the process of translation to affect transcription of the operon directly.
At the beginning of the transcribed genes of the trp operon is a sequence of at least 130 nucleotides termed the leader transcript (trpL; ). Lee and Yanofsky (1977) found that the attenuation efficiency is correlated with the stability of a secondary structure embedded in trpL, and the 2 constituent hairpins of the terminator structure were later elucidated by Oxender et al. (1979). This transcript includes four short sequences designated 1–4, each of which is partially complementary to the next one. Thus, three distinct secondary structures (hairpins) can form: 1–2, 2–3 or 3–4. The hybridization of sequences 1 and 2 to form the 1–2 structure is rare because the RNA polymerase waits for a ribosome to attach before continuing transcription past sequence 1, however if the 1–2 hairpin were to form it would prevent the formation of the 2–3 structure (but not 3–4). The formation of a hairpin loop between sequences 2–3 prevents the formation of hairpin loops between both 1–2 and 3–4. The 3–4 structure is a transcription termination sequence (abundant in G/C and immediately followed by several uracil residues), once it forms RNA polymerase will disassociate from the DNA and transcription of the structural genes of the operon can not occur (see below for a more detailed explanation). The functional importance of the 2nd hairpin for the transcriptional termination is illustrated by the reduced transcription termination frequency observed in experiments destabilizing the central G+C pairing of this hairpin.
Part of the leader transcript codes for a short polypeptide of 14 amino acids, termed the leader peptide. This peptide contains two adjacent tryptophan residues, which is unusual, since tryptophan is a fairly uncommon amino acid (about one in a hundred residues in a typical E. coli protein is tryptophan). The strand 1 in trpL encompasses the region encoding the trailing residues of the leader peptide: Trp, Trp, Arg, Thr, Ser; conservation is observed in these 5 codons whereas mutating the upstream codons do not alter the operon expression. If the ribosome attempts to translate this peptide while tryptophan levels in the cell are low, it will stall at either of the two trp codons. While it is stalled, the ribosome physically shields sequence 1 of the transcript, preventing the formation of the 1–2 secondary structure. Sequence 2 is then free to hybridize with sequence 3 to form the 2–3 structure, which then prevents the formation of the 3–4 termination hairpin, which is why the 2–3 structure is called an anti-termination hairpin. In the presence of the 2–3 structure, RNA polymerase is free to continue transcribing the operon. Mutational analysis and studies involving complementary oligonucleotides demonstrate that the stability of the 2–3 structure corresponds to the operon expression level. If tryptophan levels in the cell are high, the ribosome will translate the entire leader peptide without interruption and will only stall during translation termination at the stop codon. At this point the ribosome physically shields both sequences 1 and 2. Sequences 3 and 4 are thus free to form the 3–4 structure which terminates transcription. This terminator structure forms when no ribosome stalls in the vicinity of the Trp tandem (i.e. Trp or Arg codon): either the leader peptide is not translated or the translation proceeds smoothly along the strand 1 with abundant charged tRNAtrp. More over, the ribosome is proposed to only block about 10 nts downstream, thus ribosome stalling in either the upstream Gly or further downstream Thr do not seem to affect the formation of the termination hairpin. The end result is that the operon will be transcribed only when tryptophan is unavailable for the ribosome, while the trpL transcript is constitutively expressed.
This attenuation mechanism is experimentally supported. First, the translation of the leader peptide and ribosomal stalling are directly evidenced to be necessary for inhibiting the transcription termination. Moreover, mutational analysis destabilizing or disrupting the base-pairing of the antiterminator hairpin results in increased termination of several folds; consistent with the attenuation model, this mutation fails to relieve attenuation even with starved Trp. In contrast, complementary oligonucleotides targeting strand 1 increases the operon expression by promoting the antiterminator formation. Furthermore, in histidine operon, compensatory mutation shows that the pairing ability of strands 2–3 matters more than their primary sequence in inhibiting attenuation.
In attenuation, where the translating ribosome is stalled determines whether the termination hairpin will be formed. In order for the transcribing polymerase to concomitantly capture the alternative structure, the time scale of the structural modulation must be comparable to that of the transcription. To ensure that the ribosome binds and begins translation of the leader transcript immediately following its synthesis, a pause site exists in the trpL sequence. Upon reaching this site, RNA polymerase pauses transcription and apparently waits for translation to begin. This mechanism allows for synchronization of transcription and translation, a key element in attenuation.
A similar attenuation mechanism regulates the synthesis of histidine, phenylalanine and threonine.
Regulation of trp operon in Bacillus subtilis
The arrangement of the trp operon in E. coli and Bacillus subtilis differs. There are 5 structural genes in E. coli that are found under a single transcriptional unit. In Bacillus subtilis, there are 6 structural genes that are situated within a supraoperon. Three of these genes are found upstream while the other three genes are found downstream of the trp operon. There is a 7th gene in Bacillus subtiliss operon called trpG or pabA which is responsible for protein synthesis of tryptophan and folate. Regulation of trp operons in both organisms depends on the amount of trp present in the cell. However, the primary regulation of tryptophan biosynthesis in B. subtilis is via attenuation, rather than repression, of transcription. In B. subtilis'', tryptophan binds to the eleven-subunit tryptophan-activated RNA-binding attenuation protein (TRAP), which activates TRAP's ability to bind to the trp leader RNA. Binding of trp-activated TRAP to leader RNA results in the formation of a terminator structure that causes transcription termination. In addition, the activated TRAP inhibits the initiation of translation of trpP, trpE, trpG and ycbK genes. The gene trpP plays a role in trp transportation, while the gene trpG is utilized in the folate operon, and the gene ycbK is involved in synthesis of an efflux protein. The activated TRAP protein is regulated by an anti-TRAP protein and AT synthesis. AT can inactive TRAP to lower the transcription of tryptophan.
References
Further reading
External links
Animation of the Trp operon's regulation
Gene expression
Operons | Trp operon | [
"Chemistry",
"Biology"
] | 2,383 | [
"Gene expression",
"Molecular genetics",
"Cellular processes",
"Molecular biology",
"Biochemistry",
"Operons"
] |
5,556,327 | https://en.wikipedia.org/wiki/Natalie%20Jeremijenko | Natalie Jeremijenko (born 1966) is an artist and engineer whose background includes studies in biochemistry, physics, neuroscience and precision engineering. She is an active member of the net.art movement, and her work primarily explores the interface between society, the environment and technology.
She has alternatively described her work as "X Design" (short for experimental design) and herself as a "thingker", a combination of thing-maker and thinker. In 2018, she was Artist in Residence at Dartmouth College, and is currently an associate professor at New York University in the Visual Art Department, and has affiliated faculty appointments in the school's Computer Science and Environmental Studies.
Early life and education
She was born in Mackay, Queensland, and raised in Brisbane, the second of ten children to a physician and a schoolteacher. Her parents were champions of domestic technology, and Jeremijenko claims that her mother was the first woman in Australia to own a microwave.
She has a PhD in computer science and electrical engineering from the University of Queensland, and additionally did coursework for a PhD in mechanical engineering at Stanford University, without completing the degree.
Transition to art installations
In 1988, Jeremijenko co-founded the Livid rock festival in Brisbane. She credits her involvement in helping her move towards public art as she created installations that would appeal to the young crowd.
Notable works
D4PA: Designed 4 Political Action
A catalogue of devices and strategies for political engagement and direct action developed by the Bureau of Inverse Technology and others. Described by Wired Magazine as "the DARPA of dissent".
Live Wire (Dangling String), 1995
In 1995, as an artist-in-residence at Xerox PARC in Palo Alto, California under the guidance of Mark Weiser, she created an art installation made up of spinning strings that changed speed relative to the amount of internet traffic. The work is now seen as one of the first examples of ambient or "calm" technology.
OneTrees
One Tree(s) was a public experiment that provided material and scientific evidence on environmental and cultural issues. It explored issues such as global warming, air quality and genetically modified organisms. This art installation facilitates personal interpretation. It brilliantly uses the concept of information and conceptual art to communicate science. It removes the use of documentation like charts and graphs and challenges the concept of pure visualization in presenting information to its audience.
OOZ
Various technological interfaces to facilitate interaction with natural systems as opposed to virtual systems. These interfaces encourage interactive relationships with non-humans and are intended to accumulate the actions of participants into productive local environmental knowledge and the remediation of urban territories.
HowStuffIsMade
How Stuff is Made (HSIM) is a visual encyclopedia documenting the manufacturing processes, environmental costs and labour conditions involved in the production of contemporary products. This is a wiki-based collectively produced academic project to change the information available on and about the production.
Feral Robots
An open source robotics project providing resources and support for upgrading the raison d'etre of commercially available robotic dog toys; and facilitating mediagenic Feral Robotic Dog Pack Release events. Because the dogs follow concentration gradients of the contaminants they are equipped to sniff, their release renders information legible to diverse participants, provides the opportunity for evidence-driven discussion, and facilitates public participation in environmental monitoring and remediation.
BIT Plane, 1997
The BIT plane is a radio-controlled model aircraft, designed by the Bureau of Inverse Technology and equipped with a micro-video camera and transmitter. Its name could be a reference to bit plane, a set of digital discrete signals. In 1997, it was launched on a series of sorties over the Silicon Valley to capture an aerial rendering.
Guided by the live control-view video feed from the plane, the pilot on the ground could steer the unit deep into the heartlands of the Information Age. Most of the corporate research parks in Silicon Valley are no-camera zones and require US citizen status or special clearance for entry. The bit plane (with an undisclosed citizenship) flew covertly through this rarified information-space, buzzing over the largest concentration of venture capital in the world, returning with several hours of aerial footage.
Suicide Box
Suicide Box consists of motion sensor cameras, placed on the Golden Gate Bridge for an initial 100 day period. The name is a reference to the location, the Golden Gate Bridge ranking amongst the most popular suicide spots in the United States. Cameras were installed without permission from local municipal authorities. Data recorded by the footage, vertical motions assumed to be suicides, came out to an average of .68 suicides per day over the duration of the project. Footage was later compared against information about fluctuations in the Dow Jones Industrial Average, the average being popularly held as an indicator of the economy's health. A commonly held conception is that suicides increase during times of economic downturn, though the comparison of data from "Suicide Box" when compared to DOW fluctuations indicated no correlations.
Controversies surrounding the work related to its subject matter and authenticity. Questions have been raised with regards to the authenticity of the footage (whether or not what are depicted are actually suicides) and the subject matter (the depiction of actual suicides as part of an art piece).
Biotech Hobbyist magazine
(1st issue) An online magazine with kits and resources to bring biotech to the garage, bedroom, and everyman, to raise the standards of evidence and capacity for public involvement in the political decisions on the biotechnological future.
Bat Billboard, 2008
Created in 2008, this project's goal was to dispel misinformation, as well as educate people on bats, their habitat, and activities. The billboard was an interactive home for bats that would display written messages based on the sonar messages the bats were sending. This work was showcased at MoMA's 2011 exhibit "Talk to Me".
The Art of The Eco-mindshift, 2009
Jeremijenko gave a TED Talk in October 2009. Here she discussed her various projects and what she was currently working on with the Environmental Health Clinic. In the TED Talk she also discusses what her plans are to improve the environment in industrious areas like New York City.
Awards
2013 Creative Capital Emerging Fields Award
2011 Fast Company'''s Most Influential Women in Technology
2005 I.D. magazine annual Forty (#37)
1999 Rockefeller Fellow
1999 Technology Review'''s Top 100 Young Innovators
Personal life
She was previously married to the sociologist Dalton Conley with whom she had two children: E and Yo. Jeremijenko also has a daughter, Jamba, from a previous relationship.
Selected works
See also
Critical technical practice
References
Further reading
External links
Natalie Jeremijenko's home page with info about projects
xDesign Environmental Health Clinic
2012 outdoor work at Socrates Sculpture Park
Info from Yale University
Profile of artist with descriptions of her work
video interview at Connected Environments exhibit at the Neuberger Museum of Art
MoMA Talk To Me Exhibition Site
Natalie Jeremijenko TED Talk
1966 births
20th-century Australian artists
20th-century Australian engineers
20th-century Australian women artists
20th-century Australian women engineers
21st-century Australian artists
21st-century Australian engineers
21st-century Australian women artists
21st-century Australian women engineers
Australian conceptual artists
Australian digital artists
Australian emigrants to the United States
Australian installation artists
Australian women engineers
Critical design practitioners
Electronic literature writers
Environmental artists
Griffith University alumni
Living people
Mass media theorists
Net.artists
Officers of the Order of Australia
Ubiquitous computing researchers
University of Queensland alumni
Women conceptual artists
Women digital artists
Women installation artists | Natalie Jeremijenko | [
"Technology"
] | 1,528 | [
"Multimedia",
"Net.artists"
] |
5,556,494 | https://en.wikipedia.org/wiki/Pindone | Pindone is an anticoagulant drug for agricultural use. It is commonly used as a rodenticide in the management of rat and rabbit populations.
It is pharmacologically analogous to warfarin and inhibits the synthesis of Vitamin K-dependent clotting factors.
See also
1,3-Indandione
References
Vitamin K antagonists
Rodenticides
1,3-Indandiones
Anticoagulant rodenticides | Pindone | [
"Biology"
] | 98 | [
"Biocides",
"Rodenticides"
] |
5,556,716 | https://en.wikipedia.org/wiki/Romanian%20numbers | Romanian numbers are the system of number names used in Romanian to express counts, quantities, ranks in ordered sets, fractions, multiplication, and other information related to numbers.
In Romanian grammar, the words expressing numbers are sometimes considered a separate part of speech, called (plural: ), along with nouns, verbs, etc. (Note that the English word "numeral" can mean both the symbols used for writing numbers and the names of those numbers in a given language; also, Romanian only partially overlaps in meaning with English number.) Nevertheless, these words play the same roles in the sentence as they do in English: adjective, pronoun, noun, and adverb. This article focuses on the mechanism of naming numbers in Romanian and the use of the number names in sentences.
The symbols for numbers in Romanian texts are the same as those used in English, with the exception of using the comma as the decimal separator and the period or the space (ideally a narrow space) for grouping digits by three in large numbers. For example, in Romanian 1,5 V means one and a half volts, and 1.000.000 or 1 000 000 means one million.
General characteristics
As in other numeral systems, the Romanian number names use a limited set of words and combining rules, which can be applied to generate the name of any number within sufficiently large limits.
The general characteristics of the number formation rules in Romanian are:
The numeration base used is decimal.
Word order is big-endian with the exception of numbers from 11 to 19.
Large numbers use a combined form of the long and short scales.
Connection words are used in certain situations.
Some number names have two gender-specific forms.
Cardinal numbers
Cardinal numbers are the words we use for counting objects or expressing quantity.
Number name for 0
The number 0 is called . Like in English, it requires the plural form of nouns: "zero degrees", with being the plural form of ). Unlike English, the reading of number/numeral 0 is always and never replaced with words like oh, naught, nil, love, etc.
Numbers from 1 to 10
The number names from 1 to 10 derive from Latin. The table below gives the cardinal numbers in Romanian and the three other Eastern Romance languages (sometimes considered to be its dialects): Aromanian, Megleno-Romanian and Istro-Romanian.
Notes
1. When counting, the number names for 1 and 2 have the forms given in the table; however, when used in a sentence, they change according to the gender of the noun they modify or replace. It is worth noting that the two adjectival forms of the cardinal number for 1 ( and ) are identical with the corresponding indefinite articles.
"one boy, a boy",
"one of the boys",
"one girl, a girl",
"one of the girls",
"two boys",
"two girls".
2. The name for number five in Aromanian, written or , might be responsible for nicknaming the Aromanians țințar.
3. Sometimes pronounced as (initially a regionalism), more common when communicating telephone numbers, in order to avoid a possible confusion between and .
4. In Istro-Romanian, depending on the speaker, some number names are replaced with their Croatian (Slavic) equivalents.
Numbers from 11 to 19
Unlike all other Romance languages, Romanian has a consistent way of naming the numbers from 11 to 19. These are obtained by joining three elements: the units, the word (derived from Latin "over", but now meaning "towards" in Romanian), and the word for "ten". For example, fifteen is , which literally means "five over ten". This is the only exception to the big-endian principle of number naming.
The table below gives the forms of all nine such number names. Each number in the series has one or more shortened variants, often used in informal speech, where the element ' is replaced by . Prescriptive grammarians consider the informal variants to be indicative of careless speech.
Notes
1. The number name for 12 given in the table is the masculine form; this is the only number in this range that also has a feminine form: (informal ). However, the masculine form is sometimes used even with feminine nouns, especially when the number follows the noun it determines, as in "12 o'clock" or ("12th grade", see below for ordinal numbers); such use is considered incorrect.
2. Number names for 14 and 16 do not exactly follow the forming rule, possibly under the influence of the number names for 12 and 13. The forms and do exist, but are perceived as hypercorrect and very rarely used (one might hear them in telephone conversations, for the sake of correct transmission).
3. Instead of sometimes is used.
4. The number name for 18 is notorious for being the word in Romanian with the longest consonant cluster (five consonants with no intervening vowels): , split into two syllables, . For this reason, the variants (with a missing ) and or (with an additional vowel to break the consonant cluster) are frequent.
Numbers from 20 to 99
The numbers in this range that are multiple of 10 (that is, 20, 30, ..., 90) are named by joining the number of tens with the word (the plural of ), as shown in the table below. Note that they are spelled as a single word.
Notes
1. is often pronounced (but not written) . Similarly, is often pronounced .
2. does not follow the formation rule exactly. The expected form does not exist.
3. This is a direct descendant of Latin , which did not survive in Romanian.
The other numbers between 20 and 99 are named by combining three words: the number of tens, the conjunction "and", and the units. For example, 42 is .
For those numbers whose unit figure is 1 or 2 the corresponding number name has two gender-dependent forms:
masculine: "31 men"; "32 men";
feminine: "31 women"; "32 women";
neuter: "31 degrees"; "32 degrees".
Short versions
The numbers from 20 to 99 also have an informal, simplified pronunciation: The part shortens to when the units name starts with an unvoiced consonant or a vowel. For 50 and 80 this contraction is incomplete, reducing only to . When the next word starts with a voiced consonant the same rule applies except that is pronounced voiced as . The same rule applies if the units number is 0 and if the next word is the preposition . Examples:
→ ("75");
→ ("51");
→ ("88");
→ ("32");
→ ("20 times").
In regional speech further simplification is possible ( becoming and becoming ). Also, the number , when it refers to the revolutions of 1848, is pronounced , which also gave words like (meaning "participant in the Romanian 1848 Revolution" or "supporter of its ideology").
Numbers from 100 to 999
Any given number from 100 to 999 can be named by first saying the hundreds and then, without any connecting word, the two-digit number of tens and units; for example, 365 is trei sute șaizeci și cinci.
Note that the word for "hundred" is sută, and that if the number of hundreds is 2 or larger, the plural sute is required. The noun sută itself is feminine and as such the numbers 100 and 200 are o sută and două sute.
In fast utterances, the numbers 500 and 800 are usually pronounced cinsute and opsute, instead of the standard forms cinci sute and opt sute, respectively. In writing, however, the informal variants are only used for stylistic effects.
Large numbers
The table below lists the numbers representing powers of 10 larger than 100, that have a corresponding single-word name. The word for 1000 is feminine, all the others are neuter; this is important in the number naming. In Romanian, neuter nouns behave like masculine in the singular and like feminine in the plural.
To say any cardinal number larger than 1000 the number is split in groups of three digits, from right to left (into units, thousands, millions, etc.), then the groups are read from left to right as in the example below.
12,345,678 (written in Romanian 12.345.678) = douăsprezece milioane trei sute patruzeci și cinci de mii șase sute șaptezeci și opt
When a digit is zero, the corresponding quantity is simply not pronounced:
101,010 (written in Romanian 101.010) = o sută una mii zece
In writing, the groups of three digits are separated by dots. The comma is used as decimal separator. This may be confusing for native English speakers, who use the two symbols the other way around.
Decimal fractions
Numbers represented as decimal fractions (for example 1.62) are expressed by reading in order the integer part, the decimal separator, and the fractional part. This is the same as in English, with the following exceptions:
The decimal separator is the comma, in Romanian virgulă. For example, 2.5 is written 2,5 and pronounced doi virgulă cinci.
The fractional part is read as a multi-digit number, not by saying each digit independently. For example, 3.14 (written 3,14) is pronounced trei virgulă paisprezece (literally three comma fourteen). However, when the number of decimals is too large, they can be read one by one as a string of digits: trei virgulă unu patru unu cinci nouă (3.14159).
Decimal fractions whose integer part is 0 (such as 0.6) are always written and pronounced in Romanian together with the initial zero: 0,6 is read zero virgulă șase, unlike English point six.
In some situations it is customary to say cu "with" instead of virgulă. For example, medical staff might be heard stating the body temperature in words like treizeci și șapte cu cinci, meaning 37.5 °C.
Percents
Percentages (%) and permillages (‰) are read using the words la sută and la mie, like in the examples: cinci la sută (5%), nouă la mie (9‰). For percentages an alternative reading uses the neuter noun procent, meaning 1%; the previous example becomes cinci procente.
Negative numbers
Negative numbers are named just like in English, by placing the word minus, pronounced , at the beginning: −10 m is minus zece metri.
Preposition de
Syntactically, when a cardinal number determines a noun and when the number has certain values, the preposition de (roughly equivalent to of) is inserted between the number name and the modified noun in a way similar to English hundreds of birds. Example: șaizeci de minute "sixty minutes".
The rules governing the use of preposition de are as follows:
For numbers from 0 to 19 de is not used. The same applies to numbers whose last two digits make a number in the range from 1 to 19. Examples: șapte case "seven houses", șaisprezece ani "16 years (old)", o sută zece metri "110 meters".
An exception to this rule is when the objects that are counted are symbols (letters, numbers). In this case, for better understanding the meaning, de can be used, although the practice is sometimes criticized. Example: se scrie cu doi de i "it's written with two i's", doi de zece "two tens", "two A grades".
Another exception is for numbers whose last two digits are 01, in which case an optional de is sometimes used. Examples: o mie una de ori "1001 times", o sută unu de dalmațieni "101 Dalmatians". In the latter case the choice might be influenced by euphony (avoidance of the alliteration).
For integer numbers from 20 to 100, preposition de is placed between the number name and the modified noun. The same applies to numbers whose last two digits are either 00 or make a number in the range from 20 to 99. Examples: douăzeci de metri "twenty meters", o mie de ori "a thousand times".
In technical contexts, to save space, the preposition de may be dropped, especially in writing: 200 metri plat "200 meters sprint". In expressing quantities using measurement unit symbols the preposition de is never written, but usually pronounced: 24 V → douăzeci și patru de volți "24 V, twenty-four volts".
For non-integer decimal numbers de is never used: 20,5 kg (read douăzeci virgulă cinci kilograme, "20.5 kg").
For negative numbers all the rules and exceptions above apply unchanged: −20 °C is minus douăzeci de grade Celsius, −5 m is minus cinci metri, −23,4 V is minus douăzeci și trei virgulă patru volți, etc.
The preposition de is also used within the syntax of the number itself, for stating the number of thousands, millions, billions, etc.: douăzeci de mii "twenty thousand" (also note the plural mii, unlike the singular thousand in English). The rules for this de are the same as those described above: it is used when the last two digits of the number of thousands, millions, etc. are 00 or 20–99. Again, in technical contexts, this de may be dropped: treizeci milioane euro "thirty million euros".
Agreement between number name and modified noun
The number name and the noun it modifies must agree in number and gender.
The rule for number agreement is simple: When the number is 1, the modified noun is put in its singular form, otherwise it takes the plural form, including the case of number 0 and all non-integer numbers.
The gender agreement is somewhat complicated by the fact that the Romanian nouns are classified into three genders: masculine, feminine, and neuter. Specifically, the neuter gender is a combination of the other two: A neuter noun behaves like a masculine noun in the singular, and like a feminine noun in the plural. The gender has implications on the morphology of some of the grammatically connected words, including the number names.
When the units digit of a number is 1 or 2, its name has two distinct forms, masculine and feminine. The only exception is unsprezece "eleven" which has only one form used for both genders.
The gender agreement requires the choice of masculine number names for masculine nouns, and feminine number names for feminine nouns. For the neuter nouns the agreement is obtained by choosing the masculine name of the number not just for number 1, but for all other numbers whose units digit is 1, despite the fact that the noun behaves as feminine; for numbers whose last digit is 2 the feminine numeral is chosen. Examples:
Note
1. Although, as a neuter noun in the plural, scaune behaves like a feminine noun, the masculine form of the numeral douăzeci și unu is used. This is because unu "one" also represents a number by itself; in the singular, the neuter noun requires a masculine modifier. If the noun is also modified by an adjective, the feminine form of the adjective is used: douăzeci și unu de scaune galbene "21 yellow chairs".
Distributive numbers
Distributive numbers are used to show how a larger quantity is divided into smaller, equal portions. These numbers are named using the cardinal number names and the word câte (or cîte, depending on the spelling convention), roughly meaning "each", but requiring a different word order. The following examples show some distributive numbers in various cases:
Punem câte patru prăjituri pe fiecare farfurie. "We put four cakes on each plate."
Copiii merg doi câte doi. "The children are walking two by two."
Hai să ne despărțim în grupe de câte trei. "Let's split in groups of three each."
Au fost expuse desenele a câte doi elevi din fiecare clasă. "The drawings of two students in each class were displayed."
Am dat formularele câte unui copil din fiecare grupă. "I gave the forms to one child in each group." – Am dat formularele la cîte doi copii din fiecare grupă. "I gave the forms to two children in each group."
Collective numbers
Collective numbers are used when all members of a group are referred to by their number, like English all four wheels. Generally, for sets of more than a few elements, the word toți / toate ("all", masculine / feminine) is used together with the cardinal number. The use of the demonstrative cei / cele is optional in the nominative-accusative, but required in the genitive-dative. The genitive-dative form is tuturor celor for both genders. In the following examples note that the modified noun always has the nominative form, and that the definite article goes to the demonstrative where it is used:
nominative-accusative:
masculine: toți șapte piticii, toți cei șapte pitici "all seven dwarfs";
feminine: toate trei fiicele, toate cele trei fiice "all three daughters";
genitive-dative:
tuturor celor șapte pitici "of/to all seven dwarfs";
tuturor celor trei fiice "of/to all three daughters";
genitive (another pattern, using the preposition a):
numele a toți șapte piticii, numele a toți cei șapte pitici "the names of all seven dwarfs";
numele a toate trei fiicele, numele a toate cele trei fiice "the names of all three daughters";
dative (another pattern, using the preposition la):
le-am spus la toți șapte piticii, le-am spus la toți cei șapte pitici "I told all seven dwarfs";
le-am spus la toate trei fiicele, le-am spus la toate cele trei fiice "I told all three daughters".
Special words
When the number is 2 or sometimes 3 or 4, special words are used instead of toți, just as the word both replaces *all two in English. The most frequent of these words are:
amândoi/amîndoi, amândouă/amîndouă "both", with the genitive-dative form amândurora/amîndurora, which does not follow the usual declension rules;
ambii, ambele (also "both", but somewhat formal);
tustrei, tustrele "all three". This and the following collective numerals are used mainly for people and reflects a rather old style.
câteșitrei/cîteștrei, câteșitrele/cîteștrele "all three";
tuspatru "all four";
câteșipatru/cîteșipatru "all four".
Adverbial numbers
The adverbial number is the number used to show the repetition of a certain event, in constructions such as de cinci ori "five times". The table below shows a few examples of adverbial numbers.
For number 1 the usual form is o dată ("once", "one time"). The construction o oară is possible, but rarely used. In the plural, the adverbial numbers are formed using the preposition de, the cardinal number in the feminine, and the noun ori "times", which is the plural of the feminine noun oară.
Sample sentences:
Am citit cartea de trei ori. "I've read the book three times."
„Poștașul sună întotdeauna de două ori” "The postman always rings twice"
Approximate numbers can be used, like in the examples below.
ți-am spus de zeci de ori că nu mă interesează. "I've told you dozens (textually: tens] of times I'm not interested."
Am ascultat cîntecul acesta de sute de ori. "I've listened to this song hundreds of times."
Multiplicative numbers
For some numbers, special words are used to show multiplication of size, number, etc. The table below gives the most frequent such words, with their English equivalents.
The traditional multiplicative numbers are formed from the respective cardinal number with the prefix în- (changed into îm- when the following sound is a bilabial plosive), and the suffix -it, the same used to form the past participle of a large category of verbs.
In contemporary Romanian the neologisms are more frequently used.
The multiplicative number can be used as adjective and as adverb. Examples:
Adjective (note the gender agreement):
salariu întreit, salariu triplu ("triple wage", "wage three times as much");
putere întreită, putere triplă "three times more power".
Adverb (no agreement required):
Am muncit întreit. Am muncit triplu. "I worked three times harder."
Am economisit înzecit față de anul trecut. "I saved ten times as much as last year."
Often instead of the multiplicative numbers an adverbial construction is used. This can be applied for any number larger than 1.
Am muncit de trei ori mai mult față de anul trecut și am primit un salariu de zece ori mai mare. "I worked three times more than last year and earned a salary ten times bigger."
Fractional numbers
Numbers expressed as parts of a unit (such as "two thirds") are named using the cardinal number, in its masculine form, with the suffix -ime. Other morphological changes take place, as shown below.
A number like 3/5 is expressed as trei cincimi "three fifths". Since all the fractional number names behave like feminine nouns, when the numerator is 1, 2, or any other number with a distinct feminine form, that form must be used: două treimi (2/3). The preposition de is used depending also on the numerator: douăzeci de sutimi (20/100), o sută zece miimi (110/1000).
In music several other such words are frequently used for note lengths:
șaisprezecime "sixteenth note";
trezecișidoime "thirty-second note" - often pronounced treijdoime (informal);
șaizecișipătrime "sixty-fourth note" - often pronounced șaișpătrime (informal).
Fractions involving larger numbers tend to become hard to read. Especially in mathematics it is common to read fractions only using cardinal numbers and the words pe or supra ("on", "over"). For example, două treimi "two thirds" becomes doi pe trei or doi supra trei.
Ordinal numbers
The ordinal number (linguistics) is used to express the position of an object in an ordered sequence, as shown in English by words such as first, second, third, etc. In Romanian, with the exception of number 1, all ordinal numbers are named based on the corresponding cardinal number. Two gender-dependent forms exist for each number. The masculine form (also used with neuter nouns) ends in -lea, whereas the feminine form ends in -a. Starting from 2 they are preceded by the possessive article al / a.
Examples:
Am terminat de scris al treilea roman. "I finished writing the third novel."
Locuim la a cincea casă pe dreapta. "We live in the fifth house on the right."
Basic forms
The basic forms of the ordinal number are given in the table below. All other forms are made using them.
{| class="wikitable"
! rowspan="2" | Number !! colspan="2" | Ordinal number !! rowspan="2" | Meaning
|-
! masculine !! feminine
|-
| 1 || primul (întâiul/întîiul) || prima (întâia/întîia) || "the first"
|-
| 2 || al doilea || a doua || "the second"
|-
| 3 || al treilea || a treia || "the third"
|-
| 4 || al patrulea || a patra || "the fourth"
|-
| 5 || al cincilea || a cincea || "the fifth"
|-
| 6 || al șaselea || a șasea || "the sixth"
|-
| 7 || al șaptelea || a șaptea || "the seventh"
|-
| 8 || al optulea || a opta || "the eighth"
|-
| 9 || al nouălea || a noua || "the ninth"
|-
| 10 || al zecelea || a zecea || "the tenth|-
| 100 || al o sutălea || a o suta || "the one hundredth"
|-
| 1000 || al o miilea || a o mia || "the one thousandth"
|-
| 106 || al un milionulea || a o milioana || "the one millionth"
|-
| 109 || al un miliardulea || a o miliarda || "the one billionth"
|-
| ... || ... || ... || ...
|}
11-19
Ordinal numbers in this range can be formed by modifying the corresponding cardinal number: the ending -zece is transformed into -zecelea and -zecea for the masculine and feminine ordinal number. Examples:al unsprezecelea, a unsprezecea "the 11th";al doisprezecelea, a douăsprezecea "the 12th", note the gender difference doi-, două-;al treisprezecelea, a treisprezecea "the 13th", and so on.
20-99
Ordinal numbers in this range that have the unit digit 0 are formed by replacing the ending -zeci of the corresponding cardinal number with -zecilea and -zecea (masculine and feminine):al douăzecilea, a douăzecea "the 20th";al treizecilea, a treizecea "the 30th", and so on.
When the unit digit is not 0, the cardinal number is used for the tens and the ordinal number for the units. The only exception is when the unit digit is 1; in this case, instead of primul, prima a different word is used: unulea, una. Examples:al douăzeci și unulea, a douăzeci și una "the 21st";al douăzeci și doilea, a douăzeci și doua "the 22nd";al douăzeci și treilea, a douăzeci și treia "the 23rd", and so on.
All other numbers
The general rule for ordinal number formation is to combine the following elements:
the possessive article al, a;
the cardinal number without the last pronounced digit;
the ordinal number corresponding to the last pronounced digit.
Examples:
101st: al o sută unulea, a o sută una;
210th: al două sute zecelea, a două sute zecea;
700th: al șapte sutelea, a șapte suta;
As seen in the last example above, the ordinal form of the plural of 100, 1000, etc. is needed for this process. These forms are:
Examples with large numbers:
1500th: al o mie cinci sutelea, a o mie cinci suta;
2000th: al două miilea, a două mia;
17,017th: al șaptesprezece mii șaptesprezecilea, a șaptesprezece mii șaptesprezecea20,000th: al douăzeci de miilea, a douăzeci de mia;
2,000,000th: al două milioanelea, a două milioana;
2,000,000,000th: al două miliardelea, a două miliarda;
5,500,000,000th: al cinci miliarde cinci sute de miloanelea, a cinci miliarde cinci sute de miloana8,621,457,098th: al opt miliarde, șase sute douăzeci și unu de milioane, patru sute cincizeci și șapte de mii, nouăzeci și optulea; a opt miliarde, șase sute douăzeci și una de milioane, patru sute cincizeci și șapte de mii, nouăzeci și optaReverse order
In certain situations the word order in expressing the ordinal number is reversed. This occurs when the object is not necessarily perceived as an element in a sequence but rather as an indexed object. For example, instead of al treilea secol the expression secolul al treilea "third century" is used. Note that the noun must have the definite article appended. Other examples:etajul al cincilea "fifth floor";partea a doua "second part, part two";volumul al treilea "third volume, volume three";grupa a patra "fourth group".
For simplification, often the cardinal number replaces the ordinal number, although some grammarians criticize this practice: The form secolul douăzeci is seen as an incorrect variant of secolul al douăzecilea "20th century".
For number 1, the form of the ordinal number in this reverse-order construction is întâi (or întîi), in both genders: deceniul întâi "first decade", clasa întâi "first grade". For the feminine, sometimes întâia is used, which until recently used to be considered incorrect by normative works.
The same reverse order is used when naming historical figures:
Carol I (read Carol Întâi);
Carol al II-lea (read Carol al Doilea).
As seen above, ordinal numbers are often written using Roman numerals, especially in this reverse order case. The ending specific to the ordinal numbers (-lea, -a) must be preserved and connected to the Roman numeral with a hyphen. Examples:secolul al XIX-lea "19th century";clasa a V-a "5th grade";volumul I, volumul al II-lea "volume I, II".
Pronunciation
In the morphological processes described above, some pronunciation changes occur that are usually marked in writing. This section gives a few details about those pronunciation aspects not "visible" in the written form.
Non-syllabic "i"
The letter i in the word zeci (both as a separate word and in compounds), although thought by native speakers to indicate an independent sound, is only pronounced as a palatalization of the previous consonant. It does not form a syllable by itself: patruzeci "forty" is pronounced . The same applies to the last i in cinci: , including compounds: 15 is pronounced and 50 is .
However, in the case of ordinal numbers in the masculine form, before -lea the nonsylabic i becomes a full syllabic i in words like douăzecilea "20th" and in cincilea "5th" .
Semivocalic i can remain a semivowel or switch to a full vowel when followed by -lea: doi , al doilea or ("the second", masculine). It remains a semivowel when followed by -a: a treia ("the third", feminine).
Stress
The stress in numbers from 11 to 19 is on the units number, that is, the first element of the compound. Since in all nine cases that element has the stress on its first syllable, the compound itself will also have the stress on the first syllable. The same is valid for the informal short versions:unsprezece , unșpe (11);șaptesprezece , șapteșpe (17);
Numbers in the series 20, 30, ..., 90 have the normal stress on the element -zeci. However, a stress shift to the first element often occurs, probably because that element carries more information:treizeci (30);„șaizeci? – Nu, șaptezeci!” "Sixty? – No, seventy!"
Etymology
With few exceptions, the words involved in the formation of Romanian number names are inherited directly from Latin. This includes the names of all the non-zero digits, all the connecting words (și, spre, de), most of the words and prefixes used to express the non-cardinal types of numbers (toți, ori, al, în- etc.), and part of the multiple names (zece, mie). The remainder are largely relatively recent borrowings from French, such as zero, dublu, triplu, minus, plus, virgulă, milion, miliard, etc., most of which are used internationally.
But the most remarkable exception is the word sută, whose origin is still debated. It is possibly an old Slavic borrowing, although the phonetic evolution from sŭto to sută proves hard to explain. A Persian origin has also been suggested.
Usage
Dates. Calendar dates in Romanian are expressed using cardinal numbers, unlike English. For example, "the 21st of April" is 21 aprilie (read douăzeci și unu aprilie). For the first day of a month the ordinal number întâi is often used: 1 Decembrie (read Întâi Decembrie; upper case is used for names of national or international holidays). Normally the masculine form of the number is used everywhere, but when the units digit is 2, the feminine is also frequent: 2 ianuarie can be read both doi ianuarie and două ianuarie; the same applies for days 12 and 22.
Centuries. Centuries are named using ordinal numbers in reverse order: "14th century" is secolul al paisprezecelea (normally written secolul al XIV-lea). Cardinal numbers are often used although considered incorrect: secolul paisprezece. See above for details.
Royal titles. Ordinal numbers (in reverse word order) are used for naming ruling members of a monarchy and the Popes. For example: Carol al II-lea, Papa Benedict al XVI-lea. See above for details.
Particularities
In Romanian, a number like 1500 is never read in a way similar to English fifteen hundred, but always o mie cinci sute "one thousand five hundred".
Sometimes, the numbers 100 and 1000 are spelled out as una sută and una mie, instead of the usual o sută, o mie. This is to ensure that the number of hundreds or thousands is understood correctly, for example when writing out numbers as words, mostly in contexts dealing with money amounts, in forms, telegrams, etc. For example, the 100 lei note is marked with the text "UNA SUTĂ LEI". Such a spelling is very formal and used almost exclusively in writing.
The title of the book Arabian Nights is translated into Romanian as O mie și una de nopți (textually One thousand and one nights), using the conjunction și although not required by the number naming rules.
See also
Names of numbers in English
Notes
References
The Number System of Romanian
Numbers in Indo-European Languages
Detailed Romanian grammar with a section on numerals (PDF, 183 pages, 4.6 MB)
DEX online, a collection of Romanian dictionaries.
Web DEX online, web 2.0 Romanian dictionaries.
Narcisa Forăscu, "Grammar difficulties of the Romanian language": use the index on the left and select the terms "numerale" and "de (prepoziție)".
Capidan, Theodor. Aromânii, dialectul Aromân'', Academia Română, Studii și cercetări, XX 1932.
Romanian grammar
Numerals | Romanian numbers | [
"Mathematics"
] | 7,963 | [
"Numeral systems",
"Numerals"
] |
5,557,157 | https://en.wikipedia.org/wiki/Sherardising | Sherardising is a process of galvanization of ferrous metal surfaces, also called vapour galvanising and dry galvanizing. The process is named after British metallurgist Sherard Osborn Cowper-Coles (son of naval inventor Cowper Phipps Coles) who invented and patented the method c. 1900. This process involves heating the steel parts up to c. 500 °C in a closed rotating drum that contains metallic zinc dust and possibly an inert filler, such as sand. At temperatures above 300 °C, zinc evaporates and diffuses into the steel substrate forming diffusion bonded Zn-Fe-phases.
Sherardising is ideal for small parts and parts that require coating of inner surfaces, such as batches of small items. Part size is limited by drum size. It is reported that pipes up to 6 m in length for the oil industry are sherardised. If the metal surface is free of scale or oxides, no pretreatment is needed. The process is hydrogen-free, hence hydrogen embrittlement is prevented.
Application
During and shortly after World War I, German 5 pfennig and 10 pfennig coins were sherardised.
Standard
BS EN 13811: 2003 (withdrawn replaced by BS EN ISO 17668:2016)
Sherardizing. Zinc diffusion coatings on ferrous products. Specification
BS EN ISO 14713-3: 2017
Zinc coatings. Guidelines and recommendations for the protection against corrosion of iron and steel in structures. Part 3. Sherardizing
See also
Hot-dip galvanization
Corrugated galvanised iron
References
Chemical processes
Corrosion prevention
Metal plating
Zinc
sk:Zinkovanie | Sherardising | [
"Chemistry"
] | 344 | [
"Corrosion prevention",
"Metallurgical processes",
"Coatings",
"Corrosion",
"Chemical processes",
"nan",
"Chemical process engineering",
"Metal plating"
] |
5,557,538 | https://en.wikipedia.org/wiki/Abell%202667 | Abell 2667 is a galaxy cluster. It is one of the most luminous galaxy clusters in the X-ray waveband known at a redshift about 0.2 and is a well-known gravitational lens.
On 2 March 2007, a team of astronomers reported the detection of the Comet Galaxy in this cluster.
This galaxy is being ripped apart by the cluster's gravitational field and harsh environment. The finding sheds light on the mysterious process by which gas-rich spiral-shaped galaxies might evolve into gas-poor irregular or elliptical-shaped galaxies over billions of years.
See also
Abell catalogue
List of Abell clusters
X-ray astronomy
References
External links
Hubble Space Telescope
Spitzer Space Telescope
ESA news
2667
Galaxy clusters
Gravitational lensing
Abell richness class 3
Sculptor (constellation) | Abell 2667 | [
"Astronomy"
] | 161 | [
"Galaxy clusters",
"Astronomical objects",
"Constellations",
"Sculptor (constellation)"
] |
5,557,623 | https://en.wikipedia.org/wiki/Compact%20closed%20category | In category theory, a branch of mathematics, compact closed categories are a general context for treating dual objects. The idea of a dual object generalizes the more familiar concept of the dual of a finite-dimensional vector space. So, the motivating example of a compact closed category is FdVect, the category having finite-dimensional vector spaces as objects and linear maps as morphisms, with tensor product as the monoidal structure. Another example is Rel, the category having sets as objects and relations as morphisms, with Cartesian monoidal structure.
Symmetric compact closed category
A symmetric monoidal category is compact closed if every object has a dual object. If this holds, the dual object is unique up to canonical isomorphism, and is denoted .
In a bit more detail, an object is called the dual of if it is equipped with two morphisms called the unit and the counit , satisfying the equations
and
where are the introduction of the unit on the left and right, respectively, and is the associator.
For clarity, we rewrite the above compositions diagrammatically. In order for to be compact closed, we need the following composites to equal :
and :
Definition
More generally, suppose is a monoidal category, not necessarily symmetric, such as in the case of a pregroup grammar. The above notion of having a dual for each object A is replaced by that of having both a left and a right adjoint, and , with a corresponding left unit , right unit , left counit , and right counit . These must satisfy the four yanking conditions, each of which are identities:
and
That is, in the general case, a compact closed category is both left and right-rigid, and biclosed.
Non-symmetric compact closed categories find applications in linguistics, in the area of categorial grammars and specifically in pregroup grammars, where the distinct left and right adjoints are required to capture word-order in sentences. In this context, compact closed monoidal categories are called (Lambek) pregroups.
Properties
Compact closed categories are a special case of monoidal closed categories, which in turn are a special case of closed categories.
Compact closed categories are precisely the symmetric autonomous categories. They are also *-autonomous.
Every compact closed category C admits a trace. Namely, for every morphism , one can define
which can be shown to be a proper trace. It helps to draw this diagrammatically:
Examples
The canonical example is the category FdVect with finite-dimensional vector spaces as objects and linear maps as morphisms. Here is the usual dual of the vector space .
The category of finite-dimensional representations of any group is also compact closed.
The category Vect, with all vector spaces as objects and linear maps as morphisms, is not compact closed; it is symmetric monoidal closed.
Simplex category
The simplex category can be used to construct an example of non-symmetric compact closed category. The simplex category is the category of non-zero finite ordinals (viewed as totally ordered sets); its morphisms are order-preserving (monotone) maps. We make it into a monoidal category by moving to the arrow category, so the objects are morphisms of the original category, and the morphisms are commuting squares. Then the tensor product of the arrow category is the original composition operator. The left and right adjoints are the min and max operators; specifically, for a monotone map f one has the right adjoint
and the left adjoint
The left and right units and counits are:
One of the yanking conditions is then
The others follow similarly. The correspondence can be made clearer by writing the arrow instead of , and using for function composition .
Dagger compact category
A dagger symmetric monoidal category which is compact closed is a dagger compact category.
Rigid category
A monoidal category that is not symmetric, but otherwise obeys the duality axioms above, is known as a rigid category. A monoidal category where every object has a left (resp. right) dual is also sometimes called a left (resp. right) autonomous category. A monoidal category where every object has both a left and a right dual is sometimes called an autonomous category. An autonomous category that is also symmetric is then a compact closed category.
References
Monoidal categories
Closed categories | Compact closed category | [
"Mathematics"
] | 903 | [
"Closed categories",
"Mathematical structures",
"Category theory",
"Monoidal categories"
] |
5,557,857 | https://en.wikipedia.org/wiki/Pre-main-sequence%20star | A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence. Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope of interstellar dust and gas. After the protostar blows away this envelope, it is optically visible, and appears on the stellar birthline in the Hertzsprung-Russell diagram. At this point, the star has acquired nearly all of its mass but has not yet started hydrogen burning (i.e. nuclear fusion of hydrogen). The star continues to contract, its internal temperature rising until it begins hydrogen burning on the zero age main sequence. This period of contraction is the pre-main sequence stage. An observed PMS object can either be a T Tauri star, if it has fewer than 2 solar masses (), or else a Herbig Ae/Be star, if it has 2 to 8 . Yet more massive stars have no pre-main-sequence stage because they contract too quickly as protostars. By the time they become visible, the hydrogen in their centers is already fusing and they are main-sequence objects.
The energy source of PMS objects is gravitational contraction, as opposed to hydrogen burning in main-sequence stars. In the Hertzsprung–Russell diagram, pre-main-sequence stars with more than 0.5 first move vertically downward along Hayashi tracks, then leftward and horizontally along Henyey tracks, until they finally halt at the main sequence. Pre-main-sequence stars with less than 0.5 contract vertically along the Hayashi track for their entire evolution.
PMS stars can be differentiated empirically from main-sequence stars by using stellar spectra to measure their surface gravity. A PMS object has a larger radius than a main-sequence star with the same stellar mass and thus has a lower surface gravity. Although they are optically visible, PMS objects are rare relative to those on the main sequence, because their contraction lasts for only 1 percent of the time required for hydrogen fusion. During the early portion of the PMS stage, most stars have circumstellar disks, which are the sites of planet formation.
See also
Protoplanetary disk
Protostar
Stellar evolution
Young stellar object
References
Star types
Star formation | Pre-main-sequence star | [
"Astronomy"
] | 481 | [
"Star types",
"Astronomical classification systems"
] |
5,558,061 | https://en.wikipedia.org/wiki/Knowledge%20Interchange%20Format | Knowledge Interchange Format (KIF) is a computer language designed to enable systems to share and re-use information from knowledge-based systems. KIF is similar to frame languages such as KL-One and LOOM but unlike such language its primary role is not intended as a framework for the expression or use of knowledge but rather for the interchange of knowledge between systems. The designers of KIF likened it to PostScript. PostScript was not designed primarily as a language to store and manipulate documents but rather as an interchange format for systems and devices to share documents. In the same way KIF is meant to facilitate sharing of knowledge across different systems that use different languages, formalisms, platforms, etc.
KIF has a declarative semantics. It is meant to describe facts about the world rather than processes or procedures. Knowledge can be described as objects, functions, relations, and rules. It is a formal language, i.e., it can express arbitrary statements in first order logic and can support reasoners that can prove the consistency of a set of KIF statements. KIF also supports non-monotonic reasoning. KIF was created by Michael Genesereth, Richard Fikes and others participating in the DARPA knowledge sharing Effort.
Although the original KIF group intended to submit to a formal standards body, that did not occur. A later version called Common Logic has since been developed for submission to ISO and has been approved and published. A variant called SUO-KIF is the language in which the Suggested Upper Merged Ontology is written.
A practical application of the Knowledge interchange format is an agent communication language in a multi-agent system.
See also
Knowledge Query and Manipulation Language
References
External links
Knowledge Interchange Format page at the Stanford AI Lab
Common Logic
Knowledge representation languages
Ontology (information science)
Logic in computer science | Knowledge Interchange Format | [
"Mathematics",
"Technology"
] | 370 | [
"Logic in computer science",
"Mathematical logic",
"Computer science stubs",
"Computer science",
"Computing stubs"
] |
8,736,688 | https://en.wikipedia.org/wiki/Psychomanteum | In parapsychology and Spiritualism, a psychomanteum is a small, enclosed area set up with a comfortable chair, dim lighting, and a mirror angled so as not to reflect anything but darkness intended to communicate with spirits of the dead.
History
The psychomanteum was popularized by Raymond Moody, originator of the term near-death experience, in his 1993 book, Reunions: Visionary Encounters with Departed Loved Ones. Raymond Moody believed the psychomanteum was useful as a tool to resolve grief. The chamber was kept darkened and illuminated only by a candle or a dim light bulb. Subjects gaze into the reflected darkness hoping to see and make contact with spirits of the dead. Moody compared the psychomanteum to the Greek Necromanteion, and said its function was a form of scrying.
See also
References
External links
"Experiencing the Psychomanteum" - Joe Nickell
Divination
Mirrors
Parapsychology
Pseudoscience
Rooms
Spiritualism | Psychomanteum | [
"Engineering"
] | 200 | [
"Rooms",
"Architecture"
] |
8,736,713 | https://en.wikipedia.org/wiki/Mobile%20RFID | Mobile RFID (M-RFID) are services that provide information on objects equipped with an RFID tag over a telecommunication network. The reader or interrogator can be installed in a mobile device such as a mobile phone or PDA.
Unlike ordinary fixed RFID, mobile RFID readers are mobile, and the tags fixed, instead of the other way around. The advantages of M-RFID over RFID include the absence of wires to fixed readers and the ability of a small number of mobile readers can cover a large area, instead of dozens of fixed readers.
The main focus is on supporting supply chain management. But this application has also found its way in m-commerce. The customer in the supermarket can scan the Electronic Product Code from the tag and connects via the internet to get more information.
ISO/IEC 29143 "Information technology — Automatic Identification and Data Capture Technique — Air Interface specification for Mobile RFID interrogator" is the first standard to be developed for Mobile RFID.
References
See also
MIIM
RFID
RTLS
ISO
Mobile telecommunications
Radio-frequency identification | Mobile RFID | [
"Technology",
"Engineering"
] | 221 | [
"Radio-frequency identification",
"Mobile telecommunications",
"Radio electronics"
] |
8,737,421 | https://en.wikipedia.org/wiki/Series%20acceleration | In mathematics, a series acceleration method is any one of a collection of sequence transformations for improving the rate of convergence of a series. Techniques for series acceleration are often applied in numerical analysis, where they are used to improve the speed of numerical integration. Series acceleration techniques may also be used, for example, to obtain a variety of identities on special functions. Thus, the Euler transform applied to the hypergeometric series gives some of the classic, well-known hypergeometric series identities.
Definition
Given an infinite series with a sequence of partial sums
having a limit
an accelerated series is an infinite series with a second sequence of partial sums
which asymptotically converges faster to than the original sequence of partial sums would:
A series acceleration method is a sequence transformation that transforms the convergent sequences of partial sums of a series into more quickly convergent sequences of partial sums of an accelerated series with the same limit. If a series acceleration method is applied to a divergent series then the proper limit of the series is undefined, but the sequence transformation can still act usefully as an extrapolation method to an antilimit of the series.
The mappings from the original to the transformed series may be linear sequence transformations or non-linear sequence transformations. In general, the non-linear sequence transformations tend to be more powerful.
Overview
Two classical techniques for series acceleration are Euler's transformation of series and Kummer's transformation of series. A variety of much more rapidly convergent and special-case tools have been developed in the 20th century, including Richardson extrapolation, introduced by Lewis Fry Richardson in the early 20th century but also known and used by Katahiro Takebe in 1722; the Aitken delta-squared process, introduced by Alexander Aitken in 1926 but also known and used by Takakazu Seki in the 18th century; the epsilon method given by Peter Wynn in 1956; the Levin u-transform; and the Wilf-Zeilberger-Ekhad method or WZ method.
For alternating series, several powerful techniques, offering convergence rates from all the way to for a summation of terms, are described by Cohen et al.
Euler's transform
A basic example of a linear sequence transformation, offering improved convergence, is Euler's transform. It is intended to be applied to an alternating series; it is given by
where is the forward difference operator, for which one has the formula
If the original series, on the left hand side, is only slowly converging, the forward differences will tend to become small quite rapidly; the additional power of two further improves the rate at which the right hand side converges.
A particularly efficient numerical implementation of the Euler transform is the van Wijngaarden transformation.
Conformal mappings
A series
can be written as , where the function f is defined as
The function can have singularities in the complex plane (branch point singularities, poles or essential singularities), which limit the radius of convergence of the series. If the point is close to or on the boundary of the disk of convergence, the series for will converge very slowly. One can then improve the convergence of the series by means of a conformal mapping that moves the singularities such that the point that is mapped to ends up deeper in the new disk of convergence.
The conformal transform needs to be chosen such that , and one usually chooses a function that has a finite derivative at w = 0. One can assume that without loss of generality, as one can always rescale w to redefine . We then consider the function
Since , we have . We can obtain the series expansion of by putting in the series expansion of because ; the first terms of the series expansion for will yield the first terms of the series expansion for if . Putting in that series expansion will thus yield a series such that if it converges, it will converge to the same value as the original series.
Non-linear sequence transformations
Examples of such nonlinear sequence transformations are Padé approximants, the Shanks transformation, and Levin-type sequence transformations.
Especially nonlinear sequence transformations often provide powerful numerical methods for the summation of divergent series or asymptotic series that arise for instance in perturbation theory, and therefore may be used as effective extrapolation methods.
Aitken method
A simple nonlinear sequence transformation is the Aitken extrapolation or delta-squared method,
defined by
This transformation is commonly used to improve the rate of convergence of a slowly converging sequence; heuristically, it eliminates the largest part of the absolute error.
See also
Shanks transformation
Minimum polynomial extrapolation
Van Wijngaarden transformation
References
C. Brezinski and M. Redivo Zaglia, Extrapolation Methods. Theory and Practice, North-Holland, 1991.
G. A. Baker Jr. and P. Graves-Morris, Padé Approximants, Cambridge U.P., 1996.
Herbert H. H. Homeier: Scalar Levin-Type Sequence Transformations, Journal of Computational and Applied Mathematics, vol. 122, no. 1–2, p 81 (2000). , .
Brezinski Claude and Redivo-Zaglia Michela : "The genesis and early developments of Aitken's process, Shanks transformation, the -algorithm, and related fixed point methods", Numerical Algorithms, Vol.80, No.1, (2019), pp.11-133.
Delahaye J. P. : "Sequence Transformations", Springer-Verlag, Berlin, ISBN 978-3540152835 (1988).
Sidi Avram : "Vector Extrapolation Methods with Applications", SIAM, ISBN 978-1-61197-495-9 (2017).
Brezinski Claude, Redivo-Zaglia Michela and Saad Yousef : "Shanks Sequence Transformations and Anderson Acceleration", SIAM Review, Vol.60, No.3 (2018), pp.646–669. doi:10.1137/17M1120725 .
Brezinski Claude : "Reminiscences of Peter Wynn", Numerical Algorithms, Vol.80(2019), pp.5-10.
Brezinski Claude and Redivo-Zaglia Michela : "Extrapolation and Rational Approximation", Springer, ISBN 978-3-030-58417-7 (2020).
External links
Convergence acceleration of series
GNU Scientific Library, Series Acceleration
Digital Library of Mathematical Functions
Numerical analysis
Asymptotic analysis
Summability methods
Perturbation theory | Series acceleration | [
"Physics",
"Mathematics"
] | 1,342 | [
"Sequences and series",
"Mathematical analysis",
"Mathematical structures",
"Summability methods",
"Computational mathematics",
"Quantum mechanics",
"Mathematical relations",
"Asymptotic analysis",
"Numerical analysis",
"Approximations",
"Perturbation theory"
] |
8,738,092 | https://en.wikipedia.org/wiki/Galileo%27s%20Leaning%20Tower%20of%20Pisa%20experiment | Between 1589 and 1592, the Italian scientist Galileo Galilei (then professor of mathematics at the University of Pisa) is said to have dropped "unequal weights of the same material" from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass, according to a biography by Galileo's pupil Vincenzo Viviani, composed in 1654 and published in 1717. The basic premise had already been demonstrated by Italian experimenters a few decades earlier.
According to the story, Galileo discovered through this experiment that the objects fell with the same acceleration, proving his prediction true, while at the same time disproving Aristotle's theory of gravity (which states that objects fall at speed proportional to their mass). Though Viviani wrote that Galileo conducted "repeated experiments made from the height of the Leaning Tower of Pisa in the presence of other professors and all the students," most historians consider it to have been a thought experiment rather than a physical test.
Background
The 6th-century Byzantine Greek philosopher and Aristotelian commentator John Philoponus argued that the Aristotelian assertion that objects fall proportionately to their weight was incorrect. By 1544, according to Benedetto Varchi, the Aristotelian premise was disproven experimentally by at least two Italians. In 1551, Domingo de Soto suggested that objects in free fall accelerate uniformly. Two years later, mathematician Giambattista Benedetti questioned why two balls, one made of iron and one of wood, would fall at the same speed. All of this preceded the 1564 birth of Galileo Galilei.
Delft tower experiment
A similar experiment was conducted in Delft in the Netherlands, by the mathematician and physicist Simon Stevin and Jan Cornets de Groot (the father of Hugo de Groot). The experiment is described in Stevin's 1586 book De Beghinselen der Weeghconst (The Principles of Statics), a landmark book on statics:
Let us take (as the highly educated Jan Cornets de Groot, the diligent researcher of the mysteries of Nature, and I have done) two balls of lead, the one ten times bigger and heavier than the other, and let them drop together from 30 feet high, and it will show, that the lightest ball is not ten times longer under way than the heaviest, but they fall together at the same time on the ground. ... This proves that Aristotle is wrong.Asimov, Isaac (1964). Asimov's Biographical Encyclopedia of Science and Technology.
Galileo's experiment
At the time when Viviani asserts that the experiment took place, Galileo had not yet formulated the final version of his law of falling bodies. He had, however, formulated an earlier version which predicted that bodies of the same material falling through the same medium would fall at the same speed. This was contrary to what Aristotle had taught: that heavy objects fall faster than the lighter ones, and in direct proportion to their weight. While this story has been retold in popular accounts, there is no account by Galileo himself of such an experiment, and many historians believe that it was a thought experiment. An exception is Stillman Drake, who argues that it took place, more or less as Viviani described it, as a demonstration for students.
Galileo set out his ideas about falling bodies, and about projectiles in general, in his book Two New Sciences (1638). The two sciences were the science of motion, which became the foundation-stone of physics, and the science of materials and construction, an important contribution to engineering. Galileo arrived at his hypothesis by a famous thought experiment outlined in his book On Motion. He writes:
His argument is that if we assume heavier objects do indeed fall faster than lighter ones (and conversely, lighter objects fall slower), the string will soon pull taut as the lighter object retards the fall of the heavier object. But the system considered as a whole is heavier than the heavy object alone, and therefore should fall faster. This contradiction leads one to conclude the assumption is false.
Later performances
Astronaut David Scott performed a version of the experiment on the Moon during the Apollo 15 mission in 1971, dropping a feather and a hammer from his hands. Because of the negligible lunar atmosphere, there was no drag on the feather, which reached the lunar surface at the same time as the hammer.
The basic premise behind these experiments is now known as the (weak) equivalence principle. Galileo's hypothesis that inertial mass (resistance to acceleration) equals gravitational mass (weight) was extended by Albert Einstein to include special relativity and that combination became a key concept leading to the development of the modern theory of gravity, general relativity. Physical experiments following Galileo increased the precision of the equivalence to better than one part in a trillion.
See also
Delft tower experiment
Terminal velocity (An object dropped through air from a sufficient height will reach a steady speed, called the terminal velocity, when the aerodynamic drag force pushing up on the body balances the gravitational force (weight) pulling the body down.)
Nordtvedt effect
Newton's second law
Law of Inertia
Notes
Further reading
External links
Galileo experiment on the Moon
Galileo and the Leaning Tower of Pisa
The Hammer-Feather Drop in the world’s biggest vacuum chamber
History of Pisa
Physics experiments
Leaning Tower of Pisa experiment
Scientific folklore
Articles containing video clips
1589 in the Grand Duchy of Tuscany
1589 in science
Thought experiments in physics | Galileo's Leaning Tower of Pisa experiment | [
"Physics"
] | 1,111 | [
"Experimental physics",
"Physics experiments"
] |
8,738,465 | https://en.wikipedia.org/wiki/Net%20%28Chinese%20constellation%29 | The Net mansion () is one of the Twenty-eight mansions of the Chinese constellations. It is one of the western mansions of the White Tiger.
Asterisms
References
Chinese constellations | Net (Chinese constellation) | [
"Astronomy"
] | 40 | [
"Chinese constellations",
"Constellations"
] |
8,738,566 | https://en.wikipedia.org/wiki/Etemadi%27s%20inequality | In probability theory, Etemadi's inequality is a so-called "maximal inequality", an inequality that gives a bound on the probability that the partial sums of a finite collection of independent random variables exceed some specified bound. The result is due to Nasrollah Etemadi.
Statement of the inequality
Let X1, ..., Xn be independent real-valued random variables defined on some common probability space, and let α ≥ 0. Let Sk denote the partial sum
Then
Remark
Suppose that the random variables Xk have common expected value zero. Apply Chebyshev's inequality to the right-hand side of Etemadi's inequality and replace α by α / 3. The result is Kolmogorov's inequality with an extra factor of 27 on the right-hand side:
References
(Theorem 22.5)
Probabilistic inequalities
Statistical inequalities | Etemadi's inequality | [
"Mathematics"
] | 187 | [
"Theorems in statistics",
"Statistical inequalities",
"Theorems in probability theory",
"Probabilistic inequalities",
"Inequalities (mathematics)"
] |
8,739,219 | https://en.wikipedia.org/wiki/List%20of%20endangered%20flora%20of%20Brazil | This is a partial list of the endangered flora of Brazil as listed under an act published in Portaria 37-N de 3 de abril de 1992 (Act No 37-N on April 3, 1992) by IBAMA.
Categories
Species are classified in four groups, set through criteria such as rate of decline, population size, area of geographic distribution, and degree of population and distribution fragmentation.
Critically Endangered (CR) - Portuguese: Rara (R)
Endangered (EN) - Portuguese: Em perigo (E)
Vulnerable (VU) - Portuguese: Vulnerável (V)
Data Deficient (DD) - Portuguese: Indeterminada (I)
Official state lists of endangered flora
Official list of endangered flora of Bahia Official endangered flora of Bahia map
Official list of endangered flora of Espírito Santo
Official list of endangered flora of Minas Gerais
Official list of endangered flora of Rio Grande do Sul
Anacardiaceae
Astronium fraxinifolium Schott - Category: Vulnerable (VU)
Area of geographic distribution: Bahia, Ceará, Espírito Santo, Goiás, Mato Grosso, Maranhão, Minas Gerais, Piauí, and Rio Grande do Norte.
Astronium urundeuva Engl. - Category: Vulnerable (VU)
Area of geographic distribution: Bahia, Ceará, Espírito Santo, Goiás, Mato Grosso, Maranhão, Minas Gerais, Piauí, and Rio Grande do Norte.
Araucariaceae
Araucaria angustifolia (Bertol.) Kuntze - Category: Vulnerable (VU)
Area of geographic distribution: Minas Gerais, Paraná, Rio Grande do Sul, Santa Catarina, and São Paulo
Arecaceae
Acanthococos emensis Toledo - Category: Critically Endangered (CR)
Area of geographic distribution: Minas Gerais and São Paulo
Asclepiadaceae
Ditassa arianeae Fontella & E.A.Schwarz
Area of geographic distribution:
Ditassa maricaensis Fontella & E.A.Schwarz
Area of geographic distribution:
Asteraceae
Aspilia grazielae J.U.Santos (spelled Aspilia grasielae in the bill) - Category: Data Deficient (DD)
Area of geographic distribution: Mato Grosso do Sul
Aspilia paraensis (Huber) J.U.Santos - Category: Critically Endangered (CR)
Area of geographic distribution: Pará
Aspilia pohlii Backer - Category: Data Deficient (DD)
Area of geographic distribution: Rio Grande do Norte
Aspilia procumbens Backer - Category: Critically Endangered (CR)
Area of geographic distribution: Rio Grande do Norte
Delairea aparadensis Backer - Category: Critically Endangered (CR)
Area of geographic distribution: Santa Catarina
Bromeliaceae
Aechmea apocalyptica Reitz - Category: Critically Endangered (CR)
Area of geographic distribution: Paraná, Santa Catarina, and São Paulo
Aechmea blumenavii Reitz - Category: Critically Endangered (CR)
Area of geographic distribution: Santa Catarina
Aechmea kleinii Reitz - Category: Critically Endangered (CR)
Area of geographic distribution: Santa Catarina
Aechmea pimenti-velosii Reitz - Category: Critically Endangered (CR)
Area of geographic distribution: Santa Catarina
Billbergia alfonsi-joannis Reitz - Category: Endangered (EN)
Area of geographic distribution: Espírito Santo and Santa Catarina
Caesalpinioideae
Bauhinia smilacina Steud. - Category: Vulnerable (VU)
Area of geographic distribution: Bahia and Rio de Janeiro
Caesalpinia echinata Lam. - Category: Endangered (EN)
Area of geographic distribution: Bahia, Pernambuco, Rio Grande do Norte and Rio de Janeiro
Chrysobalanaceae
Couepia schottii Fritsch
Costaceae
Costus cuspidatus (Nees & Mart.) Maas
Area of geographic distribution:
Costus fragilis Maas
Area of geographic distribution:
Costus fusiformis Maas
Area of geographic distribution:
Dicksoniaceae
Dicksonia sellowiana Hook.
Area of geographic distribution:
Faboideae
Bowdichia nitida Spruce ex Benth. (spelled Bowdickia nitida in the bill) - Category: Vulnerable (VU)
Area of geographic distribution: Amazonas, Pará and Rondônia.
Dalbergia nigra (Vell.) Allemão ex Benth. - Category: Vulnerable (VU)
Area of geographic distribution: Bahia and Espírito Santo
Lauraceae
Aniba roseodora Ducke - Category: Endangered (EN)
Area of geographic distribution: Amazonas, Pará
Dicypellium caryophyllatum Nees - Category:
Area of geographic distribution:
Lecythidaceae
Bertholletia excelsa Humb. & Bonpl. - Category: Vulnerable (VU)
Area of geographic distribution: Acre, Amazonas, Maranhão, Pará and Rondônia.
Cariniana ianeirensis Kunth
Area of geographic distribution:
Moraceae
Brosimum glaucum Taub.
Area of geographic distribution:
Brosimum glaziovii Taub.
Area of geographic distribution:
Dorstenia arifolioa Lam. - Category: Vulnerable (VU)
Area of geographic distribution: Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo
Dorstenia cayapia - Category: Endangered (EN)
Area of geographic distribution: Bahia, Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo
Dorstenia elata - Category: Critically Endangered (CR)
Area of geographic distribution: Minas Gerais, Espírito Santo, Rio de Janeiro
Dorstenia ficus - Category: Critically Endangered (CR)
Area of geographic distribution: Rio de Janeiro
Dorstenia fischeri - Category: Endangered (EN)
Area of geographic distribution: Rio de Janeiro
Dorstenia ramosa - Category: Vulnerable (VU)
Area of geographic distribution: Rio de Janeiro
Dorstenia tenuis - Category: Vulnerable (VU)
Area of geographic distribution: Paraná and Santa Catarina
Orchidaceae
Cattleya schilleriana Rchb.f.
Area of geographic distribution: endemic to Bahia, extinct in the wild.
Sapotaceae
Bumelia obtusifolia Roem. & Schult. var. excelsa (DC) Mig.
Area of geographic distribution:
See also
Conservation in Brazil
Wildlife of Brazil
List of plants of Amazon Rainforest vegetation of Brazil
List of plants of Atlantic Forest vegetation of Brazil
List of plants of Caatinga vegetation of Brazil
List of plants of Cerrado vegetation of Brazil
List of plants of Pantanal vegetation of Brazil
References
IBAMA Lista oficial de espécies da flora brasileira ameaçada de extinção (Official list of endangered flora of Brazil) Portaria 37-N de 3 de abril de 1992 (Act No 37-N on April 3, 1992).
Flora of South America by conservation status
Endangered
Brazil
.
.Brazil
Endangered species
Brazil | List of endangered flora of Brazil | [
"Biology"
] | 1,443 | [
"Lists of biota",
"Lists of plants",
"Plants"
] |
8,739,390 | https://en.wikipedia.org/wiki/Cognized%20environment | Cognized environment is a concept first introduced by the late anthropologist Roy Rappaport (1968), in contrast to what he called the operational environment (see Rappaport 1979:97-144, 1984:337-352). Rappaport was an ecological anthropologist, like Andrew P. Vayda, and wished to contrast the actual reality and adaptations (the operational environment) within a people's ecological niche – say, the existence of tsetse flies and their role in causing sleeping sickness among humans – with how the people's culture understands nature (the cognized environment) – say, the belief that witches live in those areas that science knows is the habitat of the tsetse. Rappaport's principal concern was the role of ritual in mediating the cognized and operational environments.
Another group of anthropologists later took up the use of Rappaport's concepts and applied them toward developing a school of neuroanthropology called biogenetic structuralism (see Laughlin and Brady 1978: 6, d'Aquili, Laughlin and McManus 1979: 12ff, Rubinstein, Laughlin and McManus 1984: 21ff, and Laughlin, McManus and d'Aquili 1990:82-90). According to this group, all properties and qualities of experience are mediated by our body's neuroendocrine systems. These systems function individually and collectively to model reality. The sum total of these models in the brain is the cognized environment. The operational environment refers to the actual niche in which the human or other animal with a brain dwells and adapts. The operational environment is the real world that is modelled by our cognized environment.
See also
Umwelt
References
D'Aquili, Eugene G., Charles D. Laughlin and John McManus (1979) The Spectrum of Ritual. New York: Columbia University Press.
Laughlin, C.D. and I.A. Brady (1978) Extinction and Survival in Human Populations. New York: Columbia University Press.
Laughlin, Charles D., John McManus and Eugene G. d'Aquili (1990) Brain, Symbol and Experience: Toward a Neurophenomenology of Consciousness. New York: Columbia University Press.
Rappaport, R.A. (1968) Pigs for the Ancestors. New Haven: Yale University Press.
Rappaport, R.A. (1979) Ecology, Meaning and Religion. Richmond: North Atlantic Books.
Rappaport, R.A. (1984) Pigs for the Ancestors. 2nd edition. New Haven: Yale University Press.
Rappaport, R.A. (1999) Ritual and Religion in the Making of Humanity. Cambridge: Cambridge University Press.
Rubinstein, R.A., C.D. Laughlin and J. McManus (1984) Science As Cognitive Process. Philadelphia: University of Pennsylvania Press.
Anthropology
Environmental social science | Cognized environment | [
"Environmental_science"
] | 614 | [
"Environmental social science stubs",
"Environmental social science"
] |
8,739,477 | https://en.wikipedia.org/wiki/Federation%20of%20European%20Laboratory%20Animal%20Science%20Associations | The Federation of European Laboratory Animal Science Associations is a pan-European stakeholder organisation, representing common interests in the furtherance of laboratory animal science in Europe and beyond. The organisation was founded in 1978 and is an umbrella organisation for European national or multinational associations.
Members
, the federation consisted of 22 member associations, representing 29 countries.
Association Française des Sciences et Technique de l'Animal de Laboratoire
Associazione Italiana per Scienze degli Animali da Laboratorio
Asociatia Romana pentru Stiinta Animalelor de Laborator
Baltic Laboratory Animal Science Association
Belgian Council for Laboratory Animal Science
Czech Laboratory Animal Science Association
Croatian Laboratory Animal Science Association
Dutch Association for Laboratory Animal Science
Gesellschaft für Versuchstierkunde
Georgian Association for Laboratory Animal Science
Hungarian Laboratory Animal Science Association
Hellenic Society of Biomedical and Laboratory Animal Science
Israeli Laboratory Animal Forum
Laboratory Animal Science Association (United Kingdom)
Polish Laboratory Animal Science Association
Russian Laboratory Animal Science Association
Scandinavian Society for Laboratory Animal Science
Schweizerische Gesellschaft für Versuchstierkunde
Slovenian Association for Laboratory Animals
Sociedad Española para las Ciencias del Animal de Laboratorio
Sociedade Portuguesa de Ciências em Animas de Laboratório
Türkiye Laboratuvar Hayvanları Bilimi Derneği (Turkey)
External links
Animal testing
International scientific organizations based in Europe | Federation of European Laboratory Animal Science Associations | [
"Chemistry"
] | 284 | [
"Animal testing"
] |
8,740,164 | https://en.wikipedia.org/wiki/Bad%20Astronomy | Bad Astronomy: Misconceptions and Misuses Revealed, from Astrology to the Moon Landing "Hoax" is a non-fiction book by the American astronomer Phil Plait, who is also known as "the Bad Astronomer". The book was published in 2002 and deals with various misunderstandings about space and astronomy, such as sounds being audible in space (a misconception because in the vacuum of space, sound has no medium in which to propagate).
Plait's first book received generally favorable reviews within the academic and astronomy communities and was the first volume in the Bad Science series by John Wiley & Sons Publishing
Overview
Inspired by the author's web site, "Bad Astronomy", the book attempts to explore twenty-four common astronomical fallacies and explain the scientific consensus concerning these topics within the field of astronomy.
The book explains and corrects many ideas relating to space that, according to Plait, are mistaken but nevertheless often portrayed in popular movies. Plait also dedicates much of the book to debunking the idea of a Moon landing hoax and explains why astrology should not be taken seriously. A part of the book describes the Moon's tidal effects and explains the Coriolis effect, why the sky is blue, the Big Bang and other related topics.
Many of the book's topics and arguments also are found on Plait's page at the Slate magazine blog site, but Plait explores them in greater depth in the book. He states that the book is intended to debunk popular myths and also to describe science in an easily comprehensible way.
Reception
Tormod Guldvog writes in his review that "It is indeed a gem when it comes to teaching things about common astronomical phenomena. Plait discusses common ways bad astronomy is communicated, in the media, in the classroom, and perhaps, most of all, in our own minds."
Reviewing Bad Astronomy for the National Science Teachers Association, Deborah Teuscher, Director of Pike Planetarium, praised the work as "interesting, accurate, and fun to read," recommending the book as a resource for science teachers, scientifically interested lay persons, and high school and college students as a supplement to an astronomy unit.
Publishers Weekly gave a generally favorable review, stating of the planned John Wiley & Sons "Bad Science" series that "[i]f every entry in the series is as entertaining as Plait's, good science may have a fighting chance with the American public."
An April 2002 review for UniSci's "Daily University Science News" also praised Bad Astronomy as the "ideal accompaniment for International Astronomy Day (April 20)" and quoted the author, stating that it is "dangerous to be ignorant about science. Our lives and our livelihoods depend on it."
In an October 2002 review for Sky & Telescope, Bud Sadler praised Bad Astronomy for its humor, "easily understood explanations" and "simple demonstrations" to explain what he called "the most egregious examples of ill-informed astronomy."
Content
Bad Astronomy Begins at Home
Part I of Bad Astronomy, "Bad Astronomy Begins at Home", focuses on examples of astronomical misconceptions that are typically associated with the household or classroom, including the effect of the equinox on an egg's ability to balance upright without falling onto its side, the Coriolis effect's rumored effect on direction of whirlpools in household plumbing, and astronomical misunderstandings inherent in common English idioms, such as "meteoric rise" and "dark side of the Moon". "Idiom's Delight", the chapter dealing with scientific inaccuracies that appear in everyday expressions, such as the phrase "light years ahead".
From the Earth to the Moon
Part II of the book, "From the Earth to the Moon", focuses on Earth's orbit and atmosphere and the Moon, with particular emphasis on how photon scattering results in the sky appearing blue, the impact of axial tilt on seasons, the impact of the Moon's presence, and misconceptions regarding the "Moon Size Illusion", explaining why and how the Moon appears larger when closer to the horizon.
Skies at Night are Big and Bright
Part III, "Skies at Night are Big and Bright", concentrates on the viewing of objects farther away than the radius of the Moon's orbit around Earth, including the optical "twinkle" effect when viewing some stars, the brightness and color of stars, observation of meteors and asteroids, and using astronomical observations to study the beginning of the universe. Plait's chapter on meteors and asteroids delves into terms and distinctions and explains, for example, "why small meteors are cold, not hot, when they hit the ground."
Artificial Intelligence
Part IV, "Artificial Intelligence", attempts to tackle various conspiracy theories and alternate worldviews, including the so-called Moon Landing Hoax, Young-Earth Creationism, Immanuel Velikovsky's book Worlds in Collision (which asserts that a relatively young Venus was once a part of Jupiter), extraterrestrial claims regarding unidentified flying objects (UFOs), and astrology. In "Appalled at Apollo", the section devoted to Moon landing hoax conspiracy theories, Plait examines aspects of the hoax theory and compares its claims against basic laws of physics. Astronomical Society of the Pacific listed Chapter 17, "Appalled at Apollo", on a list of resources stating it was "good ammunition for debunking the notion that NASA never went to the Moon point by point." In the chapter "Misidentified Flying Objects", Plait discusses various ways that cameras sometimes distort images, which Plait writes are often responsible for examples of evidence presented by extraterrestrial UFO proponents. A chapter devoted to astrology explores the topic, explaining "why astrology doesn't work".
Beam Me Up
Part V, "Beam Me Up", explores additional topics, such as common misconceptions regarding the Hubble Space Telescope and its funding, star-naming companies, and astronomy myths and inaccuracies perpetuated by Hollywood, providing "The Top-Ten Examples of Bad Astronomy in Major Motion Pictures".
Publications
Bad Astronomy was the first volume in the planned series Bad Science published by John Wiley & Sons. A second volume, Bad Medicine, by Christopher Wanjek, was published in 2003 and was the most recent in the series.
In 2008, Plait published a second book on astronomy, Death from the Skies, which explored the various ways in which the human race could be rendered extinct by astronomical phenomena.
See also
Death from the Skies
References
External links
Plait's Bad Astronomy blog at Slate.com
Sample chapter from publisher.
Astronomy books
American non-fiction books
2002 non-fiction books
Wiley (publisher) books
Scientific skepticism mass media | Bad Astronomy | [
"Astronomy"
] | 1,413 | [
"Astronomy books",
"Works about astronomy"
] |
8,741,819 | https://en.wikipedia.org/wiki/Mitraphylline | Mitraphylline, an oxindole derivative, is an active alkaloid in the leaves of the tree Mitragyna speciosa, commonly known as kratom. As a non-narcotic constituent, it also occurs to a significant amount in the bark of Uncaria tomentosa (Cat's Claw) along with a number of isomeric alkaloids.
Current research is focusing on antiproliferative and cytotoxic effects and its in vivo efficacy to induce apoptosis in human breast cancer, sarcoma, as well as lymphoblastic leukemia cell lines.
References
Indole alkaloids
Spiro compounds | Mitraphylline | [
"Chemistry"
] | 138 | [
"Organic compounds",
"Alkaloids by chemical classification",
"Indole alkaloids",
"Spiro compounds"
] |
8,742,025 | https://en.wikipedia.org/wiki/Life%20Quality%20Index | The Life Quality Index (LQI) is a calibrated compound social indicator of human welfare that reflects the expected length of life and enhancement of the quality of life through access to income. The Life Quality Index combines two primary social indicators: the life expectancy at birth, L, and the real gross domestic product per person, G, corrected for purchasing power parity as appropriate. Both are widely available and accurate statistics.
Basic concept
The three components of the Life Quality Index, L, G and q reflect three important human concerns: the duration of life, the creation of wealth, and the time available to enjoy life. The available lifetime to enjoy income from wealth creation acts as a multiplying factor upon the value of that wealth. Conversely, the amount of income one has to enjoy over the lifetime acts as a multiplier on the expected duration of life.
Unlike the United Nations’ Human Development Index (HDI), the LQI is derived based on considerations of the economics of human welfare. The HDI has been used primarily to rank nations in order of human welfare (development, quality of life). In contrast to the HDI, the LQI can also serve as an objective function for optimizing risk management practices and setting national or corporate goals to guide effective allocation of society’s scarce resources for the mitigation of risks to life. The LQI provides an important criterion for determination of net benefit to society – or a corporate entity - for improving the overall public welfare by reducing risks to life in a cost-effective manner.
In the accounting and assessment of human development, we can view the role of individuals as the principal means, or contributors, to development as well as the ends. For example, the productivity of an individual contributes directly to the aggregate wealth creation in a society. However, the income so generated (to whomsoever it may accrue) increases the capacity of society to provide the necessary means such as the required infrastructure (hospitals, schools, clean water, safe roads and structures). The adequacy of the infrastructure in turn benefits the individual via access to quality health and environment, education and means for cultural expression and enrichment. The LQI is a tool for enhancing our decision-making capacity to promote a rational basis for the management of risks to life and health. It brings into a sharper focus the choices and trade-offs we have to make between the costs incurred to support extension of life and its linkage to the creation of productive wealth available for the allocation of scarce resources.
Formulation
The mathematical expression for the Life-Quality Index is: LQI = LGq, showing the LQI as a function of L, the life expectancy at birth and G, the Gross Domestic Product (GDP) per person. The parameter q is a constant either based on time-budget studies available for many countries (approximately equal to 1/5 for developed nations) or upon equal marginal utility of the growth of L and G easily available for all countries and can be updated when necessary.
Societal Capacity to Commit Resources (SCCR)
The LQI has been used to determine an acceptable level of expenditure that can be justifiably incurred on behalf of the public interest in exchange for a small reduction in the risk of death that results in improved life-quality for all. This limit of benefit can be considered as the societal capacity to commit resources to sustainable risk reduction. Suppose a portion of GDP, dG, is invested in implementing a program that affects public risk, thus modifying the life expectancy by a small amount dL. There is a net benefit if there is a net increase in LQI, dL. This criterion can be derived from the definition of L as: dL/L + qdG/G > 0, from which the limit of benefit, the Societal Capacity to Commit Resources (SCCR) to sustainable risk reduction, follows as: SCCR = G/(qL).
In conjunction with an actuarial life table the SCCR serves to evaluate life-saving interventions in place of the discredited “value of a statistical life.”
Using data from the United Nations Development Programme (UNDP) for years 2000-20 for calibration and growths of L and G[6], Table 1 shows the 2023 values of LQI, dimensionless normalized to equal 1.00 for the World in year 2000, and the LQI rank for the 40 most highly developed countries. Table 2 gives 2023 values for country groupings defined by the UNDP for the HDI.
Table1. Life Quality Index 2023 rankings and values (World LQI2000 = 1.000)
Table 2. 2023 Data[6], Life Quality Index, and Societal Capacity to Commit Resources to Risk Reduction for regions and other country groupings
Application
The Life Quality Index is a decision tool serving to promote human development through better allocation of society’s scarce resources by reducing wasteful efforts on inefficient risk-reduction and identifying efficient alternatives.
Given that the societal capacity to commit resources is limited, the LQI is a powerful indicator of merit amongst competing but desirable goods, such as for example level of resources to be directed at air pollution vs water pollution vs low probability, high consequence risks in the distant future.
Measuring Equality
The Life Quality Index has been used to derive an index of equality within a country, the Life Equality Index LEI. By separating the population into two sets, one half that has the higher and one that has the lower Life Expectancy at birth, and similarly dividing it according to GDP per capita. it defines three unequal sub-populations: two most unequal ones (each between 25% and 50% of the total) and an intermediate one. The LEI equals the LQI of the lowest sub-population as a fraction of the highest. Within a selection of 42 countries totaling 62 percent of the world population, the 2016 index ranged from 47% to 74%.
Further, countries can ranked by the lowest LQI of their three sub-populations, showing how well . The countries were also compared according to the LQI of their least fortunate sub-population (ILQI), indicating how well they fared in view of their country’s available social resources.
Using the Life Quality Index or SCCR to Judge Risk
Risks influence the LQI via the age- and sex-specific mortality, calculated by changes in an actuarial life table. The safety benefit is the gain in life expectancy at birth, or life extension expected upon implementation of the program. The cost effects must also be evaluated, measured as the effect on the real gross domestic product per person (with refinements that could include correction for purchasing power parity for international comparisons). The net benefit of a program is measured, according to the SCCR, by the resultant increases in real gross domestic product per capita and life expectancy, weighted by K. The Life Quality Index may be thought of as a refinement of monetary measures commonly used in cost-benefit analysis.
Net Benefit Criterion for Managing Risk
The objective is to maximize life expectancy subject to society’s capacity to commit resources in light of existing or future constraints. Reducing risk of death and disease translates into longer lives. The length of life extension for a population can be reliably measured as the effect on the gain in life expectancy (dL). Resources and monies (-dG) are required to achieve the gains, or increases, in life expectancy. If the resources are wisely spent, i.e., below the limit of benefit SCCR, then the gains in life expectancy will be sufficiently large that there is a net increase in the Life Quality Index (LQI). In contrast, if inordinate sums are spent on activities that do not save lives or result in only meagre life extension then there is a net decrease in the LQI.
Life Quality Index as a Tool for Managing Risk
The LQI is used in the calibration of standards by the Joint Committee on Structural Safety (see Rackwitz(2008)) and has thus found its way into currently valid standards (SIA 269 and ISO 2394).
Through numerous case studies and worked examples, it has been shown how the Life Quality Index can be used to assist decision-makers in evaluating the effectiveness of regulations and activities aimed at reducing risk to life and the environment. The LQI is a versatile tool that can be used to assess a wide range of risk management problems. The examples of application of LQI include:
the effectiveness of standards and regulations for health and safety;
harmonization of structural safety standards and design goals;
assessment of air pollution standards;
efficiency of life-saving interventions and estimates of the societal willingness (or capacity) to commit resources for safety.
Development of the Life Quality Index
The concept of the Life Quality Index was first initiated at the Institute for Risk Research, University of Waterloo, Waterloo, Ontario, Canada in the early 1990s The principal investigators involved in the development of the Life Quality Index were Professors Niels Lind, Jatin Nathwani and Mahesh Pandey. Two primary publication were Lind et al. and Nathwani et al. (1997).
See also
Manchester Short Assessment of Quality of Life
Gross National Happiness
Bhutan GNH Index
Happiness economics
References
Index numbers | Life Quality Index | [
"Mathematics"
] | 1,892 | [
"Index numbers",
"Mathematical objects",
"Numbers"
] |
8,742,216 | https://en.wikipedia.org/wiki/Blue%20Origin%20Goddard | Blue Origin Goddard is the name of the first development vehicle in Blue Origin's New Shepard program, which flew for the first time on November 13, 2006. Named after rocketry pioneer Robert H. Goddard, the vehicle is a subscale demonstrator and flew up to a height of about during its initial flight. The private spacecraft venture is being funded by the billionaire founder Jeff Bezos.
Overview
The Goddard rocket used 9 BE-1 engines, and is a single stage sub-orbital test vehicle. A video, filmed on November 13, 2006, from the Corn Ranch spaceport shows the first craft to launch under the New Shepard program. The vehicle climbed for approximately 10 seconds, reaching a height of roughly before starting to descend, and making a controlled landing back on its landing legs approximately 25 seconds after take-off.
This flight marked the first time the company's founder, Jeff Bezos, broke his silence on the work of the space company. On the company's website, Bezos said: "We're working, patiently and step-by-step, to lower the cost of spaceflight [...] Accomplishing this mission will take a long time, and we're working on it methodically." Bezos founded Blue Origin in 2000 with the intention of developing a vertical take-off and landing vehicle, able to carry passengers to the edge of space. This would eventually come in the form of the New Shepard rocket, which made its debut flight in 2015. Then on July 20, 2021, New Shepard flew its first crewed flight which included Bezos as one of the crew members.
The vehicle made three flights. The second flight took place on March 22, 2007, and its third and final flight on April 19, 2007.
See also
CORONA
Kankoh-maru
Lunar Lander Challenge
Project VR-190
Project Morpheus NASA program to continue developing ALHAT and Q landers
Reusable Vehicle Testing program by JAXA
SpaceShipTwo
SpaceX reusable launch system development program
XCOR Lynx
Zarya
References
External links
Images of the vehicle and the launch
Blue Origin launch vehicles
Space tourism
Private spaceflight
2000s United States experimental aircraft
VTVL rockets | Blue Origin Goddard | [
"Astronomy"
] | 444 | [
"Rocketry stubs",
"Astronomy stubs"
] |
8,743,336 | https://en.wikipedia.org/wiki/Oil%20skimmer | An oil skimmer is a device that is designed to remove oil floating on a liquid surface. They are commonly used to recover oil from oil spills in water, or in Industrial situations where waters are contaminated with oil. Oil skimmers are designed to remove free floating oil and are not water treatment devices.
The effectiveness of a skimmer deployed in open water or oil spill recovery is highly dependent on the roughness of the surrounding water that it is working on: the more choppy the surrounding wake and water, the more water the oil skimmer will take in along with the oil, rather than take in oil alone. Oil spill skimmers can be self-propelled, used from shore, or operated from vessels, with the best choice being dependent on the specifics for the job at hand.
Oil skimmers were used to great effect to assist in the remediation of the Exxon Valdez oil spill in 1989.
Oil skimmers are also used in a large number applications other than oil spills. Examples include as a part of oil removal in vehicle wash water, fuel storage sites and workshops. Industries that extensively use oil skimmers include manufacturing, mining, oil and gas, refining, petrochemical, solvent extraction and food industries. Selecting the correct type to use depends on the nature of the intended application and the nature of the oil and water. Oil skimmers are frequently one component of oily water treatment systems.
Oil skimmers are different from swimming pool sanitation skimmers, which are designed for a similar but unrelated purpose.
Limitations and design factors
There are many different types of oil skimmer. Each type has different design features and therefore results in different applications and use. It is important to understand the design features and fluid properties before employing a particular skimmer type.
Some factors to consider are:
Oil removal flow rate: Alternative Skimmer designs have different oil removal flow rates. Volume removal rates for Oleophilic skimmer types (drum, brush, disc, belt) are comparatively low. Weir type skimmers are capable of very high oil and water removal rates. ASTM F2709 standard establishes the test procedure for determining oil recovery rate (ORR).
Oil removal concentration: It is a common misconception that oil skimmers remove concentrated or pure 'oil'; when in fact they remove a mixture of oil and water. In most situations the 'oil' mixture removed is an emulsion of oil and water more like a 'mousse'. Oleophilic and Non-Oleophilic skimmers can sometimes provide more concentrated oil in the removal stream, however will still collect entrained water.
Effectiveness with different oils: Oleophilic and Non-Oleophilic skimmers are not equally effective with all oil types due to the changing nature of the attraction forces with different oils and materials.
Effectiveness with chemicals in the water: Oleophilic skimmers may not work as effectively if there are detergents, cleaners or other surfactants in the water that interfere with the oleophilic attraction. Weir skimmers are not affected by chemicals.
Effects of trash and debris: Trash and debris may block or interfere with the operation of oil skimmers.
Skimming direction: Some skimmers only remove oil from one direction. In some situations, such as skimming from pits and tanks, it can be important to remove oil from all directions.
Service Access: Some skimmers such as disc skimmers, or weir skimmers with skimmer mounted pumps, contain heavy serviceable items of equipment mounted on the skimmer. This may require special lifting equipment and confined space entry safety considerations before servicing.
Applications
The use of skimmers in industrial applications is often required to remove oils, grease and fats prior to further treatment for environmental discharge compliance. By removing the top layer of oils, water stagnation, smell and unsightly surface scum can be reduced. Placed before an oily water treatment system an oil skimmer may give greater overall oil separation efficiency for improved discharge wastewater quality. All oil skimmers will pick up a percentage of water with the oil which will need to be decanted to obtain concentrated oil.
Types
There are three types of oil skimmers: weir, oleophilic and suction. Oleophilic skimmers include disc, belt, tube, brush, mop, brush, grooved disc, smooth drum, and grooved drum. The material chosen for an oleophilic skimmer affects the collection rate based on the material's affinity for the particular type of oil that is skimmed.
Oleophilic
Oleophilic skimmers function by using an element such as a drum, disc, belt, rope or mop to which the oil adheres as the element is moved through the oil/water surface. Adhesion is the tendency of dissimilar particles or surfaces to cling to one another (cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). Any adhering oil is then wiped or scraped from the oleophilic surface and collected in a tank. As the oil adheres to the collection surface the amount of water collected is limited. When there is no oil left, some water will be collecte. The amount collected depends on the material properties of the oleophilic element and its affinity to water. Oilophilic skimmers can remove many kinds of oil; including machine oil, kerosene, diesel oil, lubricating oil, plant oil and other liquids with specific gravity less than water.
Small oleophilic oil skimmers can be reliable and economical. Larger Oleophilic skimmers require larger drive motors with moving mechanical parts and require maintenance. Oleophilic skimmers are not effected by the oil layer thickness.
Recovery rates are lower than other types of skimmer. Recovery rates depend on the surface area of the oleophilic material, the surface speed and the material's affinity to oil as well as other factors such as temperature, specific oil makes-up, debris in the water and other chemicals that maybe present. Surfactants such as detergents, cleaners, caustics and fine suspended solids can impare the ability of oil to adhere to the oleophilic material. Simple tests are available to determine the impairment cause by these chemicals.
Belt
Belt oil skimmers use a continuous loop belt that enters and exits the oil/water surface. As the belts exits the liquid surface oil clings to both sides. Wiper blades remove the oil from the rotating belt depositing it into a collection trough where it is moved to a storage location either via gravity or a pumping system. Belts are generally wide, thin and flexible.
Drum
Drum skimmers operate by using one or more drums made from oleophilic material. As the drums rotate oil adheres to the surface, separating it from the water. Wiper blades remove the oil from the drums depositing it into the collection trough where it is pumped to a storage location. Drum skimmers are lightweight and may have a high oil recovery rate depending on the size and number of drums used. The drums can be either smooth or grooved. These types of skimmers are generally used in oil spill response and various industrial operations.
Disc
Disc skimmers are oleophilic skimmers that use a disc constructed from PVC, steel or aluminum and can be either smooth or grooved. They are capable of recovering high volumes of oil with little water. They can be equipped with either a single or multiple discs. The discs can be driven by hydraulic, electric, diesel or air motors. DISCOIL technology patented by OCS in the year 1970, is able to recover most of the hydrocarbons on the surface of water: 98% of oil with the only 2% water. It is hydraulic type and able to operate also in classified areas, as ATEX Zone 0, 1 and 2.
Non-oleophilic
Non-oleophilic skimmers are distinguished by the component used to collect the oil. A metal disc, belt or drum is used in applications where an polymeric material is inappropriate, such as in a hot alkaline aqueous parts washer. The skimmer is generally turned off whenever there is no oil to skim thus minimizing the amount of water collected. Metal skimming elements are nearly as efficient as oleophilic skimmers when oil is present.
Weir
Weir skimmers function by allowing the oil floating on the surface of the water to flow over a weir. There are two main types of weir skimmer, those that require the weir height to be manually adjusted and those where the weir height is automatic or self-adjusting. Whilst manually adjusted weir skimmer types can have a lower initial cost, the requirement for regular manual adjustment makes self-adjusting weir types more popular in most applications.
Weir skimmers will collect some water if operating when oil is no longer present. To overcome this limitation most weir type skimmers contain an automatic water drain on the oil collection tank. Large debris 20 mm plus must be prevented from entering a Weir skimmer. This is usually done with simple screens added to the skimmer or in the case of pit operation, screening debris at the entrance to collection pits.
Weir skimmers can remove oil at a greater rate than other types of skimmer. Oil removal rates of over are available. They can also pull in oil from a greater radius on a surface than other skimmers. This makes weir skimmers popular if high oil recovery rates and large coverage areas are required.
Weir type skimmers do not rely on oil adherence or coalescence and therefore are not affected by detergents, chemicals and other surfactants in the water. They are not affected by fine suspended solids in the water which can impede adherence and therefore the operation of other types of skimmer.
See also
List of waste-water treatment technologies
References
Machines
Oil spill remediation technologies
Water pollution
Water technology | Oil skimmer | [
"Physics",
"Chemistry",
"Technology",
"Engineering",
"Environmental_science"
] | 2,067 | [
"Machines",
"Water pollution",
"Physical systems",
"Mechanical engineering",
"Water technology"
] |
8,743,406 | https://en.wikipedia.org/wiki/Wagner-Jauregg%20reaction | The Wagner-Jauregg reaction is a classic organic reaction in organic chemistry, named after (son of Julius Wagner-Jauregg), describing the double Diels–Alder reaction of 2 equivalents of maleic anhydride with a 1,1-diarylethylene. After aromatization of the bis-adduct, the ultimate reaction product is a naphthalene compound with one phenyl substituent.
The reaction is unusual in that the anhydride reacts with the aromatic ring. The presence of the additional alpha-phenyl group on the phenylethene (the styryl group) activates the styryl for a Diels–Alder reaction even at the expense of its aromaticity. In contrast, unactivated styrene reacts instead at the alkene alone via a linear polymerization reaction. Styrene maleic anhydride copolymer is formed, retaining the aromaticity of the styrene.
The Diels–Alder product can be re-aromatized using elemental sulfur at high temperature, followed by a second rearomatization by decarboxylation with barium hydroxide and copper:
References
Carbon-carbon bond forming reactions
Cycloadditions
Name reactions | Wagner-Jauregg reaction | [
"Chemistry"
] | 267 | [
"Name reactions",
"Carbon-carbon bond forming reactions",
"Organic reactions"
] |
8,746,409 | https://en.wikipedia.org/wiki/Agaricus%20campestris | Agaricus campestris is a widely eaten gilled mushroom closely related to the cultivated A. bisporus (button mushroom). A. campestris is commonly known as the field mushroom or, in North America, meadow mushroom.
Taxonomy
This species was originally noted and named in 1753 by Carl Linnaeus as Agaricus campestris. It was placed in the genus Psalliota by Lucien Quelet in 1872. Some variants have been isolated over the years, a few of which now have species status, for example, Agaricus bernardii Quel. (1878), Agaricus bisporus (J.E. Lange) Imbach (1946), Agaricus bitorquis (Quel.) Sacc. (1887), Agaricus cappellianus Hlavacek (1987), and Agaricus silvicola (Vittad.) Peck (1872). Some were so similar they did not warrant even varietal status, while others have retained it. Agaricus campestris var. equestris (F.H.Moller) Pilat (1951) is still valid. A. campestris var. isabellinus (F.H.Moller) Pilat (1951), and A. campestris var. radicatus, are possibly still valid too.
The Latin specific epithet campestris means "of the fields". Common names given to the fungus include "meadow mushroom", "pink bottom", and "field mushroom".
An analysis of ribosomal DNA of a limited number of members of the genus showed A. campestris to be an early offshoot in the genus and sister taxon to A. cupreobrunneus.
Description
The cap is white, may have fine scales, and is in diameter; it is first hemispherical in shape before flattening out with maturity. The gills are initially pink, then red-brown and finally a dark brown, as is the spore print. The stipe is tall, 1–2 cm wide, predominantly white and bears a single thin ring. The taste is mild. The white flesh bruises a dingy reddish brown, as opposed to yellow in the poisonous Agaricus xanthodermus and similar species. The thick-walled, dark brown, elliptical spores measure 5.5–8 μm by 4–5 μm. Cheilocystidia are absent.
Similar species
Several species may be confused with A. campestris. The most dangerous confusion may be with the deadly Amanita virosa (one of the group colloquially called "destroying angel"), or with the deadly Amanita hygroscopica (the pink-gilled destroying angel). Amanita species may be distinguished from Agaricus by a volva at the base, remnants of a universal veil. Such a veil may also be seen surrounding adjacent smaller button mushrooms, if present. It's recommended to look for smaller sibling buttons nearby, and slice one of the them lengthwise to examine their anatomy. They may also be distinguished by a white or off-white spore print while mushrooms in the family Agaricacea are dark brown. In the US, A. camp. may also be confused with the poisonous Agaricus californicus or A. hondensis. White Clitocybe species that also grow in grassy places may be toxic. According to Moldenke, some authorities believed that the mandrakes referenced in Genesis and in Song of Solomon were not Mandragora Officinarum L, but instead might be Agaricus campestris L.
A less serious, but more common, confusion is with Agaricus xanthodermus (the yellow stainer), which causes gastrointestinal problems in many people. A. arvensis (the horse mushroom) is very similar and is an excellent edible.
Distribution and habitat
A. campestris is found in fields and grassy areas after rain from late summer onwards worldwide. It is often found on lawns in suburban areas, appearing in small groups, in fairy rings, or solitary. Owing to the demise of horse-drawn vehicles, and the subsequent decrease in the number of horses on pasture, the old "white outs" of years gone by are becoming rare events. This species is rarely found in woodland.
The mushroom has been reported from Asia, Europe, northern Africa, Australia, New Zealand, and North America.
Uses
Although edible and choice, this mushroom is not commercially cultivated on account of its fast maturing and short shelf-life.
Culinary uses of the meadow mushroom include eating it sauteed or fried, in sauces, or even sliced raw and included in salads. In flavor and texture, this mushroom is similar to the white button mushroom (A. bisporus) available in grocery stores in most Western countries. Among the similar species mentioned above, there have been cases (in fact the most common cause of fatal fungus poisoning in France) where the deadly toxic A. virosa (the destroying angel) has been consumed by individuals who mistook it for this species. The edibility of specimens collected from lawns is uncertain because of possible contamination with pesticides or other chemicals.
It is nearly identical (except microscopically) to the edible species Agaricus andrewii and A. solidipes.
Other uses
Research into fungal dressings for the treatment of ulcers, and bed sores, using fungal mycelial filaments, is ongoing. In the past, slices of A. campestris were applied to scalds and burns in parts of Scotland.
Bioactive properties
Water extracts of A. campestris have been shown to enhance the secretion of insulin, and to have insulin-like effects on glucose metabolism in vitro, although the mechanism is not understood.
See also
List of Agaricus species
Gallery
References
External links
Agaricus campestris in the "Checklist of the British & Irish Basidiomycota"
Agaricus spp in "Mushroom-Collecting.com"
Agaricus campestris in "MushroomExpert.com"
campestris
Edible fungi
Fungi described in 1753
Taxa named by Carl Linnaeus
Fungi of Africa
Fungi of Asia
Fungi of Australia
Fungi of Europe
Fungi of New Zealand
Fungi of North America
Fungus species
Fungi used for fiber dyes | Agaricus campestris | [
"Biology"
] | 1,310 | [
"Fungi",
"Fungus species"
] |
8,746,431 | https://en.wikipedia.org/wiki/Lesser%20palatine%20nerve | The lesser palatine nerves (posterior palatine nerve) are branches of the maxillary nerve (CN V2). They descends through the greater palatine canal alongside the greater palatine nerve, and emerge (separately) through the lesser palatine foramen to pass posteriorward. They supply the soft palate, tonsil, and uvula.
See also
Greater palatine nerve
References
External links
()
Trigeminal nerve
Otorhinolaryngology
Nervous system | Lesser palatine nerve | [
"Biology"
] | 91 | [
"Organ systems",
"Nervous system"
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.