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Pesticide drift occurs when pesticides suspended in the air as particles are carried by wind to other areas, potentially contaminating them. Pesticides are one of the causes of water pollution, and some pesticides are persistent organic pollutants and contribute to soil and flower (pollen, nectar) contamination. In add... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Pesticides that evaporate into the atmosphere at relatively high temperature can be carried considerable distances (thousands of kilometers) by the wind to an area of lower temperature, where they condense and are carried back to the ground in rain or snow. In order to reduce negative impacts, it is desirable... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Alternatives to pesticides are available and include methods of cultivation, use of biological pest controls (such as pheromones and microbial pesticides), genetic engineering, and methods of interfering with insect breeding. Application of composted yard waste has also been used as a way of controlling pests... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Interfering with insects' reproduction can be accomplished by sterilizing males of the target species and releasing them, so that they mate with females but do not produce offspring. This technique was first used on the screwworm fly in 1958 and has since been used with the medfly, the tsetse fly, and the gyp... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Some advantages of using the push-pull method are less use of chemical or biological materials and better protection against insect habituation to this control method. Some disadvantages of the push-pull strategy is that if there is a lack of appropriate knowledge of behavioral and chemical ecology of the hos... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Pesticides are often referred to according to the type of pest they control. Pesticides can also be considered as either biodegradable pesticides, which will be broken down by microbes and other living beings into harmless compounds, or persistent pesticides, which may take months or years before they are bro... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide This inhibition causes an increase in synaptic acetylcholine and over-stimulation of the parasympathetic nervous system. Many of these insecticides, first developed in the mid 20th century, are very poisonous. Although commonly used in the past, many older chemicals have been removed from the market due to th... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Biopesticides fall into three major classes: Pesticides that are related to the type of pests are: The term pesticide also include these substances: Many countries, pesticides must be approved for sale and use by a government agency. In Europe, EU legislation has been approved banning the use of highly toxic ... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Three other efforts to improve regulation of international pesticide trade are the United Nations London Guidelines for the Exchange of Information on Chemicals in International Trade and the United Nations Codex Alimentarius Commission. The former seeks to implement procedures for ensuring that prior informe... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Pesticides can be created that are targeted to a specific pest's lifecycle, which can be environmentally more friendly. For example, potato cyst nematodes emerge from their protective cysts in response to a chemical excreted by potatoes; they feed on the potatoes and damage the crop. A similar chemical can be... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide Pesticides are the most thoroughly tested chemicals after drugs in the United States; those used on food requires more than 100 tests to determine a range of potential impacts. Some pesticides are considered too hazardous for sale to the general public and are designated restricted use pesticides. Only certif... | https://en.wikipedia.org/wiki?curid=48340 |
Pesticide residue refers to the pesticides that may remain on or in food after they are applied to food crops. The maximum allowable levels of these residues in foods are often stipulated by regulatory bodies in many countries. Regulations such as pre-harvest intervals also often prevent harvest of crop or livestock pr... | https://en.wikipedia.org/wiki?curid=48340 |
Polyurethane (PUR and PU) is a polymer composed of organic units joined by carbamate (urethane) links. While most polyurethanes are thermosetting polymers that do not melt when heated, thermoplastic polyurethanes are also available. polymers are traditionally and most commonly formed by reacting a di- or triisocyanate ... | https://en.wikipedia.org/wiki?curid=48366 |
Polyurethane Early work focused on the production of fibres and flexible foams and PUs were applied on a limited scale as aircraft coating during World War II. Polyisocyanates became commercially available in 1952, and production of flexible polyurethane foam began in 1954 using toluene diisocyanate (TDI) and polyester... | https://en.wikipedia.org/wiki?curid=48366 |
Polyurethane In 1969, Bayer exhibited an all-plastic car in Düsseldorf, Germany. Parts of this car, such as the fascia and body panels, were manufactured using a new process called reaction injection molding (RIM), in which the reactants were mixed and then injected into a mold. The addition of fillers, such as milled ... | https://en.wikipedia.org/wiki?curid=48366 |
Polyurethane By the late 1990s, blowing agents such as carbon dioxide, pentane, 1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1,3,3-pentafluoropropane (HFC-245fa) were widely used in North America and the EU, although chlorinated blowing agents remained in use in many developing countries. 1,1-Dichloro-1-fluoroethane (H... | https://en.wikipedia.org/wiki?curid=48366 |
Polyurethane Long chains and low crosslinking give a polymer that is very stretchy, short chains with lots of crosslinks produce a hard polymer while long chains and intermediate crosslinking give a polymer useful for making foam. The crosslinking present in polyurethanes means that the polymer consists of a three-dime... | https://en.wikipedia.org/wiki?curid=48366 |
Polyurethane Polyols are polymers in their own right and have on average two or more hydroxyl groups per molecule. Polyether polyols are mostly made by co-polymerizing ethylene oxide and propylene oxide with a suitable polyol precursor. Polyester polyols are made similarly to polyether polymers. Polyols used to make po... | https://en.wikipedia.org/wiki?curid=48366 |
Polyurethane This reaction is referred to as the blowing reaction and is catalyzed by tertiary amines like bis-(2-dimethylaminoethyl)ether. A third reaction, particularly important in making insulating rigid foams is the isocyanate trimerization reaction, which is catalyzed by potassium octoate, for example. One of the... | https://en.wikipedia.org/wiki?curid=48366 |
Phenytoin (PHT), sold under the brand name Dilantin among others, is an anti-seizure medication. It is useful for the prevention of tonic-clonic seizures and focal seizures, but not absence seizures. The intravenous form is used for status epilepticus that does not improve with benzodiazepines. It may also be used for ... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin In 2017, it was the 221st most commonly prescribed medication in the United States, with more than two million prescriptions. Common side effects include nausea, stomach pain, loss of appetite, poor coordination, increased hair growth, and enlargement of the gums. Potentially serious side effects include slee... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin is known to be a causal factor in the development of peripheral neuropathy. Folate is present in food in a polyglutamate form, which is then converted into monoglutamates by intestinal conjugase to be absorbed by the jejunum. acts by inhibiting this enzyme, thereby causing folate deficiency, and thus megalobl... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin Effects consist of the following: bleeding upon probing, increased gingival exudate, pronounced gingival inflammatory response to plaque levels, associated in some instances with bone loss but without tooth detachment. Hypertrichosis, Stevens-Johnson syndrome, purple glove syndrome, rash, exfoliative dermatit... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin may increase risk of suicidal thoughts or behavior. People on phenytoin should be monitored for any changes in mood, the development or worsening depression, and/or any thoughts or behavior of suicide. Chronic phenytoin use has been associated with decreased bone density and increased bone fractures. induces ... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin This is accomplished by reducing the amplitude of sodium-dependent action potentials through enhancing steady state inactivation. Sodium channels exist in three main conformations: the resting state, the open state, and the inactive state. binds preferentially to the inactive form of the sodium channel. Becau... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin The time to reach steady state is often longer than 2 weeks. (diphenylhydantoin) was first synthesized by German chemist Heinrich Biltz in 1908. Biltz sold his discovery to Parke-Davis, which did not find an immediate use for it. In 1938, outside scientists including H. Houston Merritt and Tracy Putnam discov... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin This was partially because Parke-Davis was reluctant to invest in a drug nearing the end of its patent life, and partially due to mixed results from various studies. In 2008, the drug was put on the FDA's Potential Signals of Serious Risks List to be further evaluated for approval. The list identifies medicat... | https://en.wikipedia.org/wiki?curid=48392 |
Phenytoin Capsules of other strengths also went up in price by the same factor—2384%, costing the UK's National Health Service an extra £43 million (about $68.44 million) a year. The companies were referred to the Competition and Markets Authority who found that they had exploited their dominant position in the market ... | https://en.wikipedia.org/wiki?curid=48392 |
Isocyanate is the functional group with the formula R−N=C=O. Organic compounds that contain an isocyanate group are referred to as isocyanates. An organic compound with two isocyanate groups is known as a diisocyanate. Diisocyanates are manufactured for the production of polyurethanes, a class of polymers. Isocyanates ... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate Upon treatment with an alcohol, an isocyanate forms a urethane linkage: If a diisocyanate is treated with a compound containing two or more hydroxyl groups, such as a diol or a polyol, polymer chains are formed, which are known as polyurethanes. Isocyanates react with water to form carbon dioxide: This react... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate Polyurethane foam boards are used in construction for insulation. TDI is commonly used in applications where flexible foams are used, such as furniture and bedding. Both MDI and TDI are used in the making of adhesives and sealants due to weather-resistant properties. Isocyanates, both MDI and TDI are widely ... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate Polyurethanes have variable curing times, and the presence of free isocyanates in foams vary accordingly. Both the US National Toxicology Program (NTP) and International Agency for Research on Cancer (IARC) have evaluated TDI as a potential human carcinogen and Group 2B "possibly carcinogenic to humans". MDI... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate Dermal exposures to isocyanates can sensitize an exposed person to respiratory disease. Dermal exposures can occur via mixing, spraying coatings or applying and spreading coatings manually. Dermal exposures to isocyanates is known to lead to respiratory sensitization. Even when using the right personal prote... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate An automated spraying booth with a separate ventilation system would be an example of engineering controls. Appropriate ventilation is a common engineering control when using isocyanates. Administrative controls are policy or training based controls to decrease hazards. A quarterly training session on recogn... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate Exposure assessment is the domain of industrial hygienists. An objective of exposure assessment is to ensure regulatory compliance with occupational exposure limits (OELs) below. OSHA guidelines provide detailed technical guidance on measuring isocyanates by sampling and analytics procedures tailored to spec... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate More recently MIC was involved in an explosion at a pesticide manufacturing plant in West Virginia. Exposure limits can be expressed as ceiling limits, a maximal value, short-term exposure limits (STEL), a 15-minute exposure limit or an 8-hour time-weighted average limit (TWA). Below is a sampling, not exhau... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate The Environmental Protection Agency (EPA) is also involved in the regulation of isocyanates with regard to the environment and also non-worker persons that might be exposed. The American Conference of Governmental Industrial Hygienists (ACGIH) is a non-government organization that publishes guidance known as... | https://en.wikipedia.org/wiki?curid=48397 |
Isocyanate The International Institute is an international industry consortium that seeks promote the safe utilization of isocyanates by promulgating best practices. | https://en.wikipedia.org/wiki?curid=48397 |
Atomic, molecular, and optical physics (AMO) is the study of matter-matter and light-matter interactions; at the scale of one or a few atoms and energy scales around several electron volts. The three areas are closely interrelated. AMO theory includes classical, semi-classical and quantum treatments. Typically, the the... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics For molecular physics, this approach is known as quantum chemistry. One important aspect of molecular physics is that the essential atomic orbital theory in the field of atomic physics expands to the molecular orbital theory. Molecular physics is concerned with atomic processes in... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics It differs from general optics and optical engineering in that it is focused on the discovery and application of new phenomena. There is no strong distinction, however, between optical physics, applied optics, and optical engineering, since the devices of optical engineering and t... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics Other important areas of research include the development of novel optical techniques for nano-optical measurements, diffractive optics, low-coherence interferometry, optical coherence tomography, and near-field microscopy. Research in optical physics places an emphasis on ultrafa... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics Experiments including electromagnetic radiation and matter - such as the photoelectric effect, Compton effect, and spectra of sunlight the due to the unknown element of Helium, the limitation of the Bohr model to Hydrogen, and numerous other reasons, lead to an entirely new mathem... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics From this basic, Planck's law was derived. In 1911, Ernest Rutherford concluded, based on alpha particle scattering, that an atom has a central pointlike proton. He also thought that an electron would be still attracted to the proton by Coulomb's law, which he had verified still h... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics Which aspects of the problem are treated quantum mechanically and which are treated classically is dependent on the specific problem at hand. The semi-classical approach is ubiquitous in computational work within AMO, largely due to the large decrease in computational cost and com... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics Atomic, Molecular and Optical physics frequently considers atoms and molecules in isolation. Atomic models will consist of a single nucleus that may be surrounded by one or more bound electrons, whilst molecular models are typically concerned with molecular hydrogen and its molecu... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic, molecular, and optical physics Any quantity of energy absorbed by the electron in excess of this amount is converted to kinetic energy according to the conservation of energy. The atom is said to have undergone the process of ionization. In the event that the electron absorbs a quantity of energy less than the ... | https://en.wikipedia.org/wiki?curid=48579 |
Atomic radius The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions ... | https://en.wikipedia.org/wiki?curid=48900 |
Atomic radius For many purposes, atoms can be modeled as spheres. This is only a crude approximation, but it can provide quantitative explanations and predictions for many phenomena, such as the density of liquids and solids, the diffusion of fluids through molecular sieves, the arrangement of atoms and ions in crystal... | https://en.wikipedia.org/wiki?curid=48900 |
Atomic radius In 1920, shortly after it had become possible to determine the sizes of atoms using X-ray crystallography, it was suggested that all atoms of the same element have the same radii. However, in 1923, when more crystal data had become available, it was found that the approximation of an atom as a sphere does... | https://en.wikipedia.org/wiki?curid=48900 |
Atomic radius The increasing nuclear charge is partly counterbalanced by the increasing number of electrons, a phenomenon that is known as shielding; which explains why the size of atoms usually increases down each column. However, there is one notable exception, known as the lanthanide contraction: the 5d block of ele... | https://en.wikipedia.org/wiki?curid=48900 |
Atomic radius The elements immediately following the lanthanides have atomic radii which are smaller than would be expected and which are almost identical to the atomic radii of the elements immediately above them. Hence hafnium has virtually the same atomic radius (and chemistry) as zirconium, and tantalum has an atom... | https://en.wikipedia.org/wiki?curid=48900 |
Kilogram per cubic metre The kilogram per cubic metre (symbol: kg·m, or kg/m) is an SI derived unit of density, defined by mass in kilograms divided by volume in cubic metres. 1 kg/m is equivalent to: 1 g/cm = 1000 kg/m = 1,000,000 g/m (exactly) 1 lb/ft ≈ 16.02 kg/m (approximately) 1 oz/gal ≈ 7.489 kg/m (approximately)... | https://en.wikipedia.org/wiki?curid=48902 |
Hydronium In chemistry, hydronium is the common name for the aqueous cation , the type of oxonium ion produced by protonation of water. It is the positive ion present when an Arrhenius acid is dissolved in water, as Arrhenius acid molecules in solution give up a proton (a positive hydrogen ion, ) to the surrounding wat... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium As shown in the images above, has a trigonal pyramidal molecular geometry with the oxygen atom at its apex. The bond angle is approximately 113°, and the center of mass is very close to the oxygen atom. Because the base of the pyramid is made up of three identical hydrogen atoms, the molecule's symmetric top ... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium It is the most acidic species that can exist in water (assuming sufficient water for dissolution): any stronger acid will ionize and protonate a water molecule to form hydronium. The acidity of hydronium is the implicit standard used to judge the strength of an acid in water: strong acids must be better proto... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium Some hydration structures are quite large: the magic ion number structure (called "magic" because of its increased stability with respect to hydration structures involving a comparable number of water molecules – this is a similar usage of the word "magic" as in nuclear physics) might place the hydronium insi... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium A 2007 calculation of the enthalpies and free energies of the various hydrogen bonds around the hydronium cation in liquid protonated water at room temperature and a study of the proton hopping mechanism using molecular dynamics showed that the hydrogen-bonds around the hydronium ion (formed with the three wa... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium In crystals grown from a benzene solution the solvent co-crystallizes and a cation is completely separated from the anion. In the cation three benzene molecules surround hydronium forming pi-cation interactions with the hydrogen atoms. The closest (non-bonding) approach of the anion at chlorine to the cation ... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium Hydronium, on the other hand, has several transitions that make it a superior candidate for detection and identification in a variety of situations. This information has been used in conjunction with laboratory measurements of the branching ratios of the various dissociative recombination reactions to provide... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium Note that the rates of these six reactions are such that they make up approximately 99% of hydronium ion's chemical interactions under these conditions. All three destruction mechanisms in the table below are classified as dissociative recombination reactions. It is also worth noting that the relative rates f... | https://en.wikipedia.org/wiki?curid=49281 |
Hydronium Once several lines had been identified in the laboratory, the first interstellar detection of HO was made by two groups almost simultaneously in 1986. The first, published in June 1986, reported observation of the "J" = 1 − 2 transition at in OMC-1 and Sgr B2. The second, published in August, reported observa... | https://en.wikipedia.org/wiki?curid=49281 |
Volatilisation Volatilization is the process whereby a dissolved sample is vaporised. In atomic spectroscopy this is usually a two-step process. The analyte is turned into small droplets in a nebuliser which are entrained in a gas flow which is in turn volatilised in a high temperature flame in the case of AAS or volat... | https://en.wikipedia.org/wiki?curid=49484 |
Volatilisation 7b01224"></ref>, since herbicidal ionic systems express lower susceptibility to volatilisation. <ref name="10.1002/cplu.201800251"></ref> | https://en.wikipedia.org/wiki?curid=49484 |
Inductively coupled plasma mass spectrometry (ICP-MS) is a type of mass spectrometry that uses an Inductively coupled plasma to ionize the sample. It atomizes the sample and creates atomic and small polyatomic ions, which are then detected. It is known and used for its ability to detect metals and several non-metals in... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The plasmas used in spectrochemical analysis are essentially electrically neutral, with each positive charge on an ion balanced by a free electron. In these plasmas the positive ions are almost all singly charged and there are few negative ions, so there are nearly equal amo... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Hyphenated techniques like Liquid Chromatography ICP-MS (LC-ICP-MS); Laser Ablation ICP-MS (LA-ICP-MS); Flow Injection ICP-MS (FIA-ICP-MS), etc. have benefited from the unique quality of this technology, that is barely 35 years old. The power of time resolved analysis can no... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry These electrons interact with the radio-frequency magnetic field of the induction coil and are accelerated first in one direction, then the other, as the field changes at high frequency (usually 27.12 million cycles per second). The accelerated electrons collide with argon a... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Samples to be analyzed are introduced into this central channel, usually as a mist of liquid formed by passing the liquid sample into a nebulizer. To maximise plasma temperature (and hence ionisation efficiency) and stability, the sample should be introduced through the cent... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The concentration of a sample can be determined through calibration with certified reference material such as single or multi-element reference standards. ICP-MS also lends itself to quantitative determinations through isotope dilution, a single point method based on an isot... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry In recent years, industrial and biological monitoring has presented another major need for metal analysis via ICP-MS. Individuals working in factories where exposure to metals is likely and unavoidable, such as a battery factory, are required by their employer to have their ... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry When the sample of interest is analysed by ICP-MS in a specialised flow cytometer, each antibody can be identified and quantitated by virtue of a distinct ICP "footprint". In theory, hundreds of different biological probes can thus be analysed in an individual cell, at a rat... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Car hit and runs, burglaries, assaults, drive-by shootings and bombings such as these situations may cause glass fragments that could be used as evidence of association in glass transfer conditions. LA-ICP-MS is considered one of the best techniques for analysis of glass due... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Previous forensic techniques employed for the organic analysis of lipsticks by compositional comparison include thin layer chromatography (TLC), gas chromatography (GC), and high-performance liquid chromatography (HPLC). These methods provide useful information regarding the... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Also the phosphorylation status of proteins can be analyzed. In 2007, a new type of protein tagging reagents called metal-coded affinity tags (MeCAT) were introduced to label proteins quantitatively with metals, especially lanthanides. The MeCAT labelling allows relative and... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The ICP-MS allows determination of elements with atomic mass ranges 7 to 250 (Li to U), and sometimes higher. Some masses are prohibited such as 40 due to the abundance of argon in the sample. Other blocked regions may include mass 80 (due to the argon dimer), and mass 56 (d... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry A simultaneous ICP-MS that can record the entire analytical spectrum from lithium to uranium in every analysis won the Silver Award at the 2010 Pittcon Editors' Awards. An ICP-MS may use multiple scan modes, each one striking a different balance between speed and precision. ... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Series of such sample measurements requires the instrument to have plasma ignited, meanwhile a number of technical parameters has to be stable in order for the results obtained to have feasibly accurate and precise interpretation. Maintaining the plasma requires a constant s... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Use of autosamplers makes this easier and faster, especially for routine work and large numbers of samples. A Desolvating Nebuliser (DSN) may also be used; this uses a long heated capillary, coated with a fluoropolymer membrane, to remove most of the solvent and reduce the l... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Electrothermal vaporization (ETV) and in torch vaporization (ITV) use hot surfaces (graphite or metal, generally) to vaporize samples for introduction. These can use very small amounts of liquids, solids, or slurries. Other methods like vapor generation are also known. The p... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The accelerated electrons collide with argon atoms, and sometimes a collision causes an argon atom to part with one of its electrons. The released electron is in turn accelerated by the rapidly changing magnetic field. The process continues until the rate of release of new e... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Liquid argon is typically cheaper and can be stored in a greater quantity as opposed to the gas form, which is more expensive and takes up more tank space. If the instrument is in an environment where it gets infrequent use, then buying argon in the gas state will be most ap... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry However, many of the interferences can be mitigated by use of a collision cell, and the greater cost of helium has prevented its use in commercial ICP-MS. The carrier gas is sent through the central channel and into the very hot plasma. The sample is then exposed to radio fr... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry Traditionally, ICP-MS instruments have used transmitting ion lens arrangements for this purpose. Examples include the Einzel lens, the Barrel lens, Agilent's Omega Lens and Perkin-Elmer's Shadow Stop. Another approach is to use ion guides (quadrupoles, hexapoles, or octopole... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The geometry of the instrument is chosen so that the instrument the combined focal point of the electrostatic and magnetic sectors is at the collector, known as Double Focussing (or Double Foccussing). If the mass of interest has a low sensitivity and is just below a much la... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The iCRC removed interfering ions using a collisional kinetic energy discrimination (KED) phenomenon and chemical reactions with interfering ions similarly to traditionally used larger collision cells. As with any piece of instrumentation or equipment, there are many aspects... | https://en.wikipedia.org/wiki?curid=49503 |
Inductively coupled plasma mass spectrometry The main component to the sample is an internal standard, which also serves as the diluent. This internal standard consists primarily of deionized water, with nitric or hydrochloric acid, and Indium and/or Gallium. Depending on the sample type, usually 5 mL of the internal s... | https://en.wikipedia.org/wiki?curid=49503 |
Standard enthalpy of formation The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states. The standard pressure value "p" = 10 Pa (= 100 kPa = 1 bar)... | https://en.wikipedia.org/wiki?curid=49887 |
Standard enthalpy of formation Since the pressure of the standard formation reaction is fixed at 1 bar, the standard formation enthalpy or reaction heat is a function of temperature. For tabulation purposes, standard formation enthalpies are all given at a single temperature: 298 K, represented by the symbol Δ"H". For ... | https://en.wikipedia.org/wiki?curid=49887 |
Standard enthalpy of formation For instance, carbon and hydrogen will not directly react to form methane (CH), so that the standard enthalpy of formation cannot be measured directly. However the standard enthalpy of combustion is readily measurable using bomb calorimetry. The standard enthalpy of formation is then dete... | https://en.wikipedia.org/wiki?curid=49887 |
Standard enthalpy of formation The heat of reaction is then "minus" the sum of the standard enthalpies of formation of the reactants (each being multiplied by its respective stoichiometric coefficient, "ν") "plus" the sum of the standard enthalpies of formation of the products (each also multiplied by its respective st... | https://en.wikipedia.org/wiki?curid=49887 |
Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare , which together make up CBRN, the military acronym for nuclear, biological, and chemical (warfare or weapons), all of which are... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Under this Convention, any toxic chemical, regardless of its origin, is considered a chemical weapon unless it is used for purposes that are not prohibited (an important legal definition known as the General Purpose Criterion). About 70 different chemicals have been used or stockpiled as chemical warfa... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare 3 million gas casualties were recorded, which may have included up to 260,000 civilian casualties. The interwar years saw occasional use of chemical weapons, mainly to put down rebellions. In Nazi Germany, much research went into developing new chemical weapons, such as potent nerve agents. However, ch... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Some 100,000 Iranian troops were casualties of Iraqi chemical weapons during the Iran–Iraq War. Iraq used mustard gas and nerve agents against its own civilians in the 1988 Halabja chemical attack. The Cuban intervention in Angola saw limited use of organophosphates. The Syrian government has used sari... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Since the development of modern chemical warfare in World War I, nations have pursued research and development on chemical weapons that falls into four major categories: new and more deadly agents; more efficient methods of delivering agents to the target (dissemination); more reliable means of defense... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare agents can be classified according to their "persistency", a measure of the length of time that a chemical agent remains effective after dissemination. Chemical agents are classified as "persistent" or "nonpersistent". Agents classified as "nonpersistent" lose effectiveness after only a few minutes or ... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare Non-volatile liquid agents, such as blister agents and the oily VX nerve agent, do not easily evaporate into a gas, and therefore present primarily a contact hazard. The droplet size used for persistent delivery goes up to 1 mm increasing the falling speed and therefore about 80% of the deployed agent ... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare These include: Most chemical weapons are assigned a one- to three-letter "NATO weapon designation" in addition to, or in place of, a common name. Binary munitions, in which precursors for chemical warfare agents are automatically mixed in shell to produce the agent just prior to its use, are indicated ... | https://en.wikipedia.org/wiki?curid=50073 |
Chemical warfare World War I saw the earliest implementation of this technique. The actual first chemical ammunition was the French 26 mm cartouche suffocante rifle grenade, fired from a flare carbine. It contained 35g of the tear-producer ethyl bromoacetate, and was used in autumn 1914 – with little effect on the Germ... | https://en.wikipedia.org/wiki?curid=50073 |
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