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Fluorescence correlation spectroscopy With the development of sensitive detectors such as avalanche photodiodes the detection of the fluorescence signal coming from individual molecules in highly dilute samples has become practical. With this emerged the possibility to conduct FCS experiments in a wide variety of speci... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy In addition, there has been a flurry of activity extending FCS in various ways, for instance to laser scanning and spinning-disk confocal microscopy (from a stationary, single point measurement), in using cross-correlation (FCCS) between two fluorescent channels instead of autocorr... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy The parameters of interest are found after fitting the autocorrelation curve to modeled functional forms. The measurement volume is a convolution of illumination (excitation) and detection geometries, which result from the optical elements involved. The resulting volume is describe... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy The Gaussian approximation works to varying degrees depending on the optical details, and corrections can sometimes be applied to offset the errors in approximation. The (temporal) autocorrelation function is the correlation of a time series with itself shifted by time formula_8, a... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy The formula allows for an interpretation of formula_18 as (i) a return probability for small beam parameters formula_19 and (ii) the moment-generating function of formula_20 if formula_19 are varied. To extract quantities of interest, the autocorrelation data can be fitted, typical... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy ) the dynamics is often not sufficiently well-described by the normal diffusion model, where the mean squared displacement (MSD) grows linearly with time. Instead the diffusion may be better described as anomalous diffusion, where the temporal dependence of the MSD is non-linear as... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy This introduces new parameters, which makes the fitting more difficult as a higher-dimensional space must be searched. Nonlinear least square fitting typically becomes unstable with even a small number of formula_37s. A more robust fitting scheme, especially useful for polydisperse... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy The autocorrelations above assume that the fluctuations are not due to changes in the fluorescent properties of the particles. However, for the majority of (bio)organic fluorophores—e.g. green fluorescent protein, rhodamine, Cy3 and Alexa Fluor dyes—some fraction of illuminated par... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy FCS almost always refers to the single point, single channel, temporal autocorrelation measurement, although the term "fluorescence correlation spectroscopy" out of its historical scientific context implies no such restriction. FCS has been extended in a number of variations by dif... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy the product of an association reaction will be larger and thus have larger diffusion times than the reactants individually); however, FCS is relatively insensitive to molecular mass as can be seen from the following equation relating molecular mass to the diffusion time of globular... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy The average molecular brightness (formula_58) is related to the variance (formula_59) and the average intensity (formula_60) as follows: Here formula_62 and formula_63 are the fractional intensity and molecular brightness, respectively, of species formula_64. Another FCS based appr... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy Raster ICS (RICS), and position sensitive FCS (PSFCS) incorporate the time delay between parts of the image scan into the analysis. Also, low-dimensional scans (e.g. a circular ring)—only possible on a scanning system—can access time scales between single point and full image measu... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy The correlation is then averaged in time. While camera white noise does not autocorrelate over time, it does over space - this creates a white noise amplitude in the spatial autocorrelation function which must be accounted for when fitting the autocorrelation amplitude in order to ... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy While conventional tracking methods break down if multiple particle trajectories intersect, this method works in principle for arbitrarily large molecule densities and dynamical parameters (e.g. diffusion coefficients, velocities) as long as individual molecules can be identified. ... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy FCS has been extended to that type of microscope, and is called TIR-FCS. Because the fluorescence intensity in TIRF falls off exponentially with distance from the coverslip (instead of as a Gaussian with a confocal), the autocorrelation function is different. Light sheet fluorescen... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy FCS experiments require a level of processing and are more sensitive to potentially confounding influences like: rotational diffusion, vibrations, photobleaching, dependence on illumination and fluorescence color, inadequate statistics, etc. It is much easier to change the measurem... | https://en.wikipedia.org/wiki?curid=2589751 |
Fluorescence correlation spectroscopy Also, particle tracking is more sensitive to noise, which can sometimes affect the results unpredictably. Several advantages in both spatial resolution and minimizing photodamage/photobleaching in organic and/or biological samples are obtained by two-photon or three-photon excitati... | https://en.wikipedia.org/wiki?curid=2589751 |
Fatigue limit The fatigue limit, also known as the endurance limit or fatigue strength, is the stress level below which an infinite number of loading cycles can be applied to a material without causing fatigue failure. Ferrous alloys and titanium alloys have a distinct limit. Other structural metals, such as aluminium ... | https://en.wikipedia.org/wiki?curid=2589816 |
Fatigue limit Typical values of the limit (formula_5) for steels are 1/2 the ultimate tensile strength, to a maximum of . For iron, aluminium, and copper alloys, formula_5 is typically 0.4 times the ultimate tensile strength. Maximum typical values for irons are , aluminums , and coppers . Note that these values are fo... | https://en.wikipedia.org/wiki?curid=2589816 |
Coral calcium is a salt of calcium derived from fossilized coral reefs (primarily from limestone and coastal deposits). It has been promoted as an alternative, but unsubstantiated, treatment or cure for a number of health conditions. has been promoted as an alternative treatment or cure for a number of health condition... | https://en.wikipedia.org/wiki?curid=2590808 |
Coral calcium Living coral reefs are endangered and cannot be harvested without significant damage to the ecosystem, and because of this, coral calcium is harvested by grinding up above-ground limestone deposits that were once part of a coral reef. Calcium from coral sources needs to be refined to remove pollutants of ... | https://en.wikipedia.org/wiki?curid=2590808 |
Dirk Coster (October 5, 1889 – February 12, 1950), was a Dutch physicist. He was a Professor of Physics and Meteorology at the University of Groningen. Coster was born in Amsterdam. On February 26, 1919, he married Lina Maria Wijsman, who held a degree in Oriental languages. Eventually, she was one of the first women t... | https://en.wikipedia.org/wiki?curid=2592182 |
Dirk Coster From 1916 to 1920 Coster was assistant of Lodewijk Siertsema and Wander de Haas at the Delft University of Technology, where in 1919 he obtained an Engineer's degree in electrical engineering. In 1920 and 1921 he did research at Lund University under Manne Siegbahn, on X-ray spectroscopy of different elemen... | https://en.wikipedia.org/wiki?curid=2592182 |
Dirk Coster In 1924 he was appointed at the University of Groningen, where he was the successor of Wander de Haas. At Groningen he started an active research program in X-ray spectroscopy. In 1934 Coster became member of the Royal Netherlands Academy of Arts and Sciences. Coster was politically involved. In 1938 he tra... | https://en.wikipedia.org/wiki?curid=2592182 |
Beta scission is an important reaction in the chemistry of thermal cracking of hydrocarbons and the formation of free radicals. Free radicals are formed upon splitting the carbon-carbon bond. Free radicals are extremely reactive and short-lived. When a free radical in a polymer chain undergoes a beta scission, the free... | https://en.wikipedia.org/wiki?curid=2592537 |
Planetary habitability is the measure of a planet's or a natural satellite's potential to develop and maintain environments hospitable to life. Life may be generated directly on a planet or satellite endogenously or be transferred to it from another body, through a hypothetical process known as panspermia. Environments... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Habitability indicators and biosignatures must be interpreted within a planetary and environmental context. In determining the habitability potential of a body, studies focus on its bulk composition, orbital properties, atmosphere, and potential chemical interactions. Stellar characteristics of i... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability 8 billion years ago, during a habitable epoch when the Universe was only 10–17 million years old. According to the panspermia hypothesis, microscopic life—distributed by meteoroids, asteroids and other small Solar System bodies—may exist throughout the Universe. Nonetheless, Earth is the only pla... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability The catalogue was formed by winnowing the nearly 120,000 stars of the larger Hipparcos Catalogue into a core group of 17,000 potentially habitable stars, and the selection criteria that were used provide a good starting point for understanding which astrophysical factors are necessary to habitabl... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability "Middle-class" stars of this sort have a number of characteristics considered important to planetary habitability: K-type stars may be able to support life far longer than the Sun. Whether fainter late K and M class red dwarf stars are also suitable hosts for habitable planets is perhaps the most... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability The habitable zone (HZ) is a shell-shaped region of space surrounding a star in which a planet could maintain liquid water on its surface. The concept was first proposed by astrophysicist Su-Shu Huang in 1959, based on climatic constraints imposed by the host star. After an energy source, liquid ... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Assumptions made about atmospheric conditions and geology thus have as great an impact on a putative HZ range as does stellar evolution: the proposed parameters of the Sun's HZ, for example, have fluctuated greatly. Second, no large-mass body such as a gas giant should be present in or relatively... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Most stars are relatively stable, but a significant minority of variable stars often undergo sudden and intense increases in luminosity and consequently in the amount of energy radiated toward bodies in orbit. These stars are considered poor candidates for hosting life-bearing planets, as their u... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Of known solar analogs, one that closely resembles the Sun is considered to be 18 Scorpii; unfortunately for the prospects of life existing in its proximity, the only significant difference between the two bodies is the amplitude of the solar cycle, which appears to be much greater for 18 Scorpii... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Whether a planet will emerge as habitable depends on the sequence of events that led to its formation, which could include the production of organic molecules in molecular clouds and protoplanetary disks, delivery of materials during and after planetary accretion, and the orbital location in the ... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability In analyzing which environments are likely to support life, a distinction is usually made between simple, unicellular organisms such as bacteria and archaea and complex metazoans (animals). Unicellularity necessarily precedes multicellularity in any hypothetical tree of life, and where single-cel... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Secondly, smaller planets have smaller diameters and thus higher surface-to-volume ratios than their larger cousins. Such bodies tend to lose the energy left over from their formation quickly and end up geologically dead, lacking the volcanoes, earthquakes and tectonic activity which supply the s... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability However, a 2008 study by the Harvard-Smithsonian Center for Astrophysics suggests that the dividing line may be higher. Earth may in fact lie on the lower boundary of habitability: if it were any smaller, plate tectonics would be impossible. Venus, which has 85% of Earth's mass, shows no signs of... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability A combination of higher escape velocity to retain lighter atoms, and extensive outgassing from enhanced plate tectonics may greatly increase the atmospheric pressure and temperature at the surface compared to Earth. The enhanced greenhouse effect of such a heavy atmosphere would tend to suggest t... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Although they are adaptive, living organisms can stand only so much variation, particularly if the fluctuations overlap both the freezing point and boiling point of the planet's main biotic solvent (e.g., water on Earth). If, for example, Earth's oceans were alternately boiling and freezing solid... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability This means that the vast majority of planets have highly eccentric orbits and of these, even if their average distance from their star is deemed to be within the HZ, they nonetheless would be spending only a small portion of their time within the zone. A planet's movement around its rotational ax... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability The exact effects of these changes can only be computer modelled at present, and studies have shown that even extreme tilts of up to 85 degrees do not absolutely preclude life "provided it does not occupy continental surfaces plagued seasonally by the highest temperature." Not only the mean axial... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability It is generally assumed that any extraterrestrial life that might exist will be based on the same fundamental biochemistry as found on Earth, as the four elements most vital for life, carbon, hydrogen, oxygen, and nitrogen, are also the most common chemically reactive elements in the universe. In... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Relative abundance in space does not always mirror differentiated abundance within planets; of the four life elements, for instance, only oxygen is present in any abundance in the Earth's crust. This can be partly explained by the fact that many of these elements, such as hydrogen and nitrogen, a... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Comets impacting with the Earth in the Solar System's early years would have deposited vast amounts of water, along with the other volatile compounds life requires onto the early Earth, providing a kick-start to the origin of life. Thus, while there is reason to suspect that the four "life elemen... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability For example, a planet that might otherwise be unable to support an atmosphere given the solar conditions in its vicinity, might be able to do so within a deep shadowed rift or volcanic cave. Similarly, craterous terrain might offer a refuge for primitive life. The Lawn Hill crater has been studie... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability In determining the feasibility of extraterrestrial life, astronomers had long focused their attention on stars like the Sun. However, since planetary systems that resemble the Solar System are proving to be rare, they have begun to explore the possibility that life might form in systems very unli... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Theoretical work by Alan Boss at the Carnegie Institution has shown that gas giants can form around stars in binary systems much as they do around solitary stars. One study of Alpha Centauri, the nearest star system to the Sun, suggested that binaries need not be discounted in the search for habi... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability 032 AU for a star like Proxima Centauri (such a world would have a year lasting just 6.3 days). At those distances, the star's gravity would cause tidal locking. One side of the planet would eternally face the star, while the other would always face away from it. The only ways in which potential ... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Further research—including a consideration of the amount of photosynthetically active radiation—suggested that tidally locked planets in red dwarf systems might at least be habitable for higher plants. Size is not the only factor in making red dwarfs potentially unsuitable for life, however. On a... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Such variation would be very damaging for life, as it would not only destroy any complex organic molecules that could possibly form biological precursors, but also because it would blow off sizeable portions of the planet's atmosphere. For a planet around a red dwarf star to support life, it woul... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Red dwarfs, by contrast, could live for trillions of years because their nuclear reactions are far slower than those of larger stars, meaning that life would have longer to evolve and survive. While the likelihood of finding a planet in the habitable zone around any specific red dwarf is slight, ... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability This supernova will disperse heavier elements throughout its vicinity, created during the phase when the massive star has moved off of the main sequence, and the systems of the potential low-mass stars (which are still on the main sequence) within the former massive-star system may be enriched wi... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Along with the characteristics of planets and their star systems, the wider galactic environment may also impact habitability. Scientists considered the possibility that particular areas of galaxies (galactic habitable zones) are better suited to life than others; the Solar System in which we liv... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability In "Evolving the Alien", biologist Jack Cohen and mathematician Ian Stewart argue astrobiology, based on the Rare Earth hypothesis, is restrictive and unimaginative. They suggest that Earth-like planets may be very rare, but non-carbon-based complex life could possibly emerge in other environment... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability "Good Jupiters" are gas giants, like the Solar System's Jupiter, that orbit their stars in circular orbits far enough away from the habitable zone not to disturb it but close enough to "protect" terrestrial planets in closer orbit in two critical ways. First, they help to stabilize the orbits, an... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability Before Earth reached half its present mass, icy bodies from the Jupiter–Saturn region and small bodies from the primordial asteroid belt supplied water to the Earth due to the gravitational scattering of Jupiter and, to a lesser extent, Saturn. Thus, while the gas giants are now helpful protector... | https://en.wikipedia.org/wiki?curid=2592906 |
Planetary habitability This oxygen proved fundamental to the respiration of later animal species. The Gaia hypothesis, a scientific model of the geo-biosphere pioneered by James Lovelock in 1975, argues that life as a whole fosters and maintains suitable conditions for itself by helping to create a planetary environmen... | https://en.wikipedia.org/wiki?curid=2592906 |
Uranyl nitrate (UO(NO)) is a water soluble yellow uranium salt. The yellow-green crystals of dioxouranium nitrate hexahydrate are triboluminescent. can be prepared by reaction of uranium salts with nitric acid. It is soluble in water, ethanol, acetone, and ether, but not in benzene, toluene, or chloroform. During the f... | https://en.wikipedia.org/wiki?curid=2593019 |
Uranyl nitrate Uranium papers were manufactured commercially at least until the end of the 19th century, vanishing due to the superior sensitivity and practical advantages of silver halides. From the 1930s through the 1950s Kodak Books described a uranium toner (Kodak T-9) using uranium nitrate hexahydrate. Some altern... | https://en.wikipedia.org/wiki?curid=2593019 |
Aluminum building wiring is a type of electrical wiring for residential construction or houses that uses aluminum electrical conductors. Aluminum provides a better conductivity to weight ratio than copper, and therefore is also used for wiring power grids, including overhead power transmission lines and local power dis... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Aluminum wire has been used as an electrical conductor for a considerable period of time, particularly by electrical utilities related to power transmission lines in use shortly after the beginning of modern power distribution systems being constructed starting in the late 1880s. Aluminum wire ... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring In the late 1960s problems and failures related to branch circuit connections for building wire made with the utility grade AA-1350 alloy aluminum began to surface, resulting in a re-evaluation of the use of that alloy for building wire and an identification of the need for newer alloys to prod... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring The 1977 Beverly Hills Supper Club fire was a notable incident triggered by poorly-installed aluminum wiring. for modern construction is manufactured with AA-8000 series aluminum alloy (sometimes referred to as "new technology" aluminum wiring) as specified by the industry standards such as the... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring As of 2017 most twist-on connectors for typical smaller branch circuit wire sizes, even those designed to connect copper to aluminum wiring, are not rated for aluminum-to-aluminum connections, with one exception being the Marette #63 or #65 used in Canada but not approved by UL for use in the U... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Over time, many of these terminations with solid aluminum wire began to fail due to improper connection techniques and the dissimilar metals having different resistances and significantly different coefficients of thermal expansion, as well as problems with properties of the solid wires. These ... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring The reported hazards are associated with older solid aluminum branch circuit wiring (smaller than ) Many terminations of aluminum wire installed in the 1960s and 1970s that were properly installed continue to operate with no problems. However, problems can develop in the future, particularly if... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Aluminum wire used before the mid-1970s had a somewhat higher rate of creep, but a more significant issue was that aluminum wire critically had a coefficient of expansion that varied significantly from steel screws commonly used in lieu of brass screws around this time for terminations at devic... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Some of these devices used larger undercut screw terminals to more securely hold the wire. Unfortunately, CU/AL switches and receptacles failed to work well enough with aluminum wire, and a new specification called CO/ALR (meaning copper-aluminum, revised) was created. These devices employ bras... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Also, due to the significant difference in thermal expansion rates of older aluminum wire and steel termination screws connections can loosen over time allowing the formation of some additional oxide on the wire. However, oxidation was found not to be a substantial factor in failures of aluminu... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring However, there may not be sufficient length of wires in enclosures to permit a special crimping tool to be used, and the resulting connections are sometimes too large to install in existing enclosures due to limited space (or "box fill"). Installing an enclosure extender for unfinished surfaces... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Special twist-on connectors (or "wire nuts") are available for joining aluminum to copper wire, which are pre-filled with an antioxidant compound made of zinc dust in polybutene base with silicon dioxide added to the compound to abrade the wires. As of 2014 there was only one twist-on connector... | https://en.wikipedia.org/wiki?curid=2595419 |
Aluminum building wiring Some researchers have criticized the UL listing/tests for this wire connector, and there have been reported problems with tests (without pre-twisting) and installations. However, it is unknown if the reported installation problems were associated with unqualified persons attempting these repair... | https://en.wikipedia.org/wiki?curid=2595419 |
Lüders band Lüders bands, also known as "slip bands" or "stretcher-strain marks," are localized bands of plastic deformation in metals experiencing tensile stresses, common to low-carbon steels and certain Al-Mg alloys. First reported by and W. Lüders, the mechanism that stimulates their appearance is known as "dynamic... | https://en.wikipedia.org/wiki?curid=2595698 |
Lüders band After the band has passed through the material the deformation proceeds uniformly with positive strain hardening. Sometimes transition into the Portevin–Le Chatelier effect while changing the temperature or strain rate, this implies these are related phenomena Lüders bands are known as a strain softening in... | https://en.wikipedia.org/wiki?curid=2595698 |
Portevin–Le Chatelier effect The (PLC) describes a serrated stress–strain curve or jerky flow, which some materials exhibit as they undergo plastic deformation, specifically inhomogeneous deformation. This effect has been long associated with dynamic strain aging or the competition between diffusing solutes pinning dis... | https://en.wikipedia.org/wiki?curid=2595792 |
Portevin–Le Chatelier effect Mason observed that under a constant loading rate, the samples would experience sudden large changes in elongation (as large as a few millimeters). Much of the underlying physics of the Portevin -Le Chatelier effect lies in a specific case of solute drag creep. Adding solute atoms to a pure... | https://en.wikipedia.org/wiki?curid=2595792 |
Portevin–Le Chatelier effect The cyclic changes described above produce serrations in the plastic region of the stress strain diagram of a tensile test that is undergoing the Portevin -Le Chatelier effect. The variation in stress also causes non-homogeneous deformation to occur throughout the sample which can be visibl... | https://en.wikipedia.org/wiki?curid=2595792 |
Portevin–Le Chatelier effect Often these precipitates will cause the so-called inverse behavior, which changes the effect of both strain rate and temperature on the solid The presence of precipitates is shown to have an influence on the appearance and disappearance of serrations in the stress strain curve. The structur... | https://en.wikipedia.org/wiki?curid=2595792 |
Portevin–Le Chatelier effect It was found that if a material is pre-strained to a value ½ of that required to initiate jerky flow, and then rested at the test temperature or annealed to remove vacancies (but low enough that the dislocation structure is not affected), then the total critical strain is only slightly decr... | https://en.wikipedia.org/wiki?curid=2595792 |
Portevin–Le Chatelier effect The different types of bands are believed to represent different states of dislocation in the bands, and band types can change in a materials stress strain curve. Currently there are no models that can capture the change in band types Portevin-Le Chatelier (PLC) effect is a proof of non-uni... | https://en.wikipedia.org/wiki?curid=2595792 |
Sodium bromate Sodium bromate, the inorganic compound with the chemical formula of NaBrO, is the sodium salt of bromic acid. It is a strong oxidant. is mainly used in continuous or batch dyeing processes involving sulfur or vat dyes and as a hair-permagent, chemical agent, or gold solvent in gold mines when used with s... | https://en.wikipedia.org/wiki?curid=2597108 |
Potassium bromate (KBrO), is a bromate of potassium and takes the form of white crystals or powder. It is a strong oxidizing agent. is produced when bromine is passed through a hot solution of potassium hydroxide. This first forms unstable potassium hypobromite, which quickly disproportionates into bromide and bromate:... | https://en.wikipedia.org/wiki?curid=2597290 |
Potassium bromate is classified as a category 2B carcinogen (possibly carcinogenic to humans) by the International Agency for Research on Cancer (IARC). has been banned from use in food products in the European Union, Argentina, Brazil, Canada, Nigeria, South Korea, Peru and some other countries. It was banned in Sri L... | https://en.wikipedia.org/wiki?curid=2597290 |
Detection limit In analytical chemistry, the detection limit, lower limit of detection, or LOD (limit of detection), is the lowest quantity of a substance that can be distinguished from the absence of that substance (a "blank value") with a stated confidence level (generally 99%). The detection limit is estimated from ... | https://en.wikipedia.org/wiki?curid=2597750 |
Detection limit However, the beta error (probability of a false negative) is 50% for a sample that has a concentration at the LOD (red line). This means a sample could contain an impurity at the LOD, but there is a 50% chance that a measurement would give a result less than the LOD. At the LOQ (blue line), there is min... | https://en.wikipedia.org/wiki?curid=2597750 |
Detection limit The 3σ of the recorded absorbance signal can be considered as the detection limit for the specific element under the experimental conditions used – wavelength, type of flame, instrument. Oftentimes there is more to the analytical method than just performing a reaction or submitting it to direct analysis... | https://en.wikipedia.org/wiki?curid=2597750 |
Detection limit This estimation, however, ignores any uncertainty that arises from performing the sample preparation and will therefore probably underestimate the true MDL. The LOQ is the limit at which the difference between two distinct values can be reasonably discerned. The LOQ may be drastically different between ... | https://en.wikipedia.org/wiki?curid=2597750 |
Yellow rain was the subject of a 1981 political incident in which the United States Secretary of State Alexander Haig accused the Soviet Union of supplying T-2 mycotoxin to the Communist states in Vietnam, Laos and Cambodia for use in counterinsurgency warfare. Refugees described many different forms of attacks, includ... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain The charges stemmed from events in Laos and North Vietnam beginning in 1975, when the two governments, which were allied with and supported by the Soviet Union, fought against Hmong tribes, peoples who had sided with the United States and South Vietnam during the Vietnam War. Refugees described events that ... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain This involved five doctors and scientists who interviewed alleged witnesses and collected samples that were purported to come from Afghanistan and Cambodia. However, the interviews produced conflicting testimony and the analyses of the samples were inconclusive. The UN experts also examined two refugees who... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain Mirocha at the University of Minnesota conducted a biochemical investigation, looking for the presence of trichothecene mycotoxins, including T-2 toxin, diacetoxyscirpenol (DAS), and deoxynivalenol (DON). This included chemical analyses of blood, urine, and tissue of alleged victims of chemical attacks in F... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain The Meselson team offered the following as evidence: separate "yellow rain drops" which occurred on the same leaf, and which were "accepted as authentic", consisted largely of pollen; each drop contained a different mix of pollen grains, as one would expect if they came from different bees, and the grains s... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain Strikingly, the Chinese villagers had also used the term "yellow rain" to describe this phenomenon. Many villagers believed that the yellow droppings were portents of imminent earthquake activity. Others believed that the droppings were chemical weapons sprayed by the Soviet Union or Taiwan. However, the Ch... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain It is now recognized that mycotoxin contamination of foods such as wheat and maize is a common problem, particularly in temperate regions of the world. As noted in a 2003 medical review, "The government research highlighted, if nothing else, that natural mycotoxicoses were an important health hazard in Sout... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain In 1982, Meselson had visited a Hmong refugee camp with samples of bee droppings that he had collected in Thailand. Most of the Hmong he interviewed claimed that these were samples of the chemical weapons that they had been attacked with. One man accurately identified them as insect droppings, but switched ... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain For instance, a 1992 review published in "Politics and the Life Sciences" described the idea of yellow rain as a biological agent as conclusively disproved and called for an assessment by the US government of the mistakes made in this episode, stating that "the present approach of sweeping the matter under ... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain " They argued that presence of pollen in yellow rain samples is best explained by the idea that "during biological warfare attacks, dispersed trichothecenes landed in pollen-containing areas." (Essentially the same position is taken in a subsequent volume in the same series of U.S. Army textbooks published ... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain This event revived memories of what "New Scientist" described as "cold war paranoia", and the article noted that the "Wall Street Journal" had covered these 1980s yellow rain allegations in particular detail. Indeed, the "Wall Street Journal" continues to assert that the Soviet Union used yellow rain as a c... | https://en.wikipedia.org/wiki?curid=2599213 |
Yellow rain " and calls for the establishment of a more rigorous inspection process to deal with such claims. Similar concerns were expressed in a 2006 review published by the World Organisation for Animal Health, which compared the American yellow rain accusations to other Cold War-era accusations from the Soviet Unio... | https://en.wikipedia.org/wiki?curid=2599213 |
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