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Methyl Bromide
Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula C H3 Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It has a tetrahedral shape and it is a recognized ozone-depleting chemical. It was used extensively as a pesticide until being phased out by most countries in the early 2000s. Occurrence and manufacture Bromomethane originates from both natural and human sources. In the ocean, marine organisms are estimated to produce 56,000 tonnes annually. It is also produced in small quantities by certain terrestrial plants, such as members of the family Brassicaceae. It is manufactured for agricultural and industrial use by treating methanol with bromine in the presence of sulfur or hydrogen sulfide: :6 CH3OH + 3 Br2 + S → 6 CH3Br + 2 H2O + H2SO4 Uses In 1999, an estimated 71,500 tonnes of synthetic methyl bromide were used annually worldwide. 97% of this estimate was used for fumigation purposes, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromoiodomethane
Bromoiodomethane is a halomethane with the formula BrCH2I. It is a colorless liquid, although older samples appear yellow. The compound has been investigated as a reagent for cyclopropanation by the Simmons-Smith reaction, but diiodomethane and chloroiodomethane Chloroiodomethane is the halomethane with the formula is . It is a colorless liquid of use in organic synthesis. Together with other iodomethanes, chloroiodomethane is produced by some microorganisms. Applications Chloroiodomethane is used in c ... are preferred. It also occurs naturally as the result of microbial action. Its critical point is at 367.85 °C and 6.3 MPa and refractive index is 1.6382 (20 °C, D). Additional reading * * * * References External linksUV Spectra data Halomethanes Organobromides Organoiodides {{Organohalide-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterilization (microbiology)
Sterilization refers to any process that removes, kills, or deactivates all forms of life (particularly microorganisms such as fungi, bacteria, spores, and unicellular eukaryotic organisms) and other biological agents such as prions present in or on a specific surface, object, or fluid. Sterilization can be achieved through various means, including heat, chemicals, irradiation, high pressure, and filtration. Sterilization is distinct from disinfection, sanitization, and pasteurization, in that those methods reduce rather than eliminate all forms of life and biological agents present. After sterilization, an object is referred to as being sterile or aseptic. Applications Foods One of the first steps toward modernized sterilization was made by Nicolas Appert, who discovered that application of heat over a suitable period slowed the decay of foods and various liquids, preserving them for safe consumption for a longer time than was typical. Canning of foods is an extension of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire Extinguisher
A fire extinguisher is a handheld active fire protection device usually filled with a dry or wet chemical used to extinguish or control small fires, often in emergencies. It is not intended for use on an out-of-control fire, such as one which has reached the ceiling, endangers the user (i.e., no escape route, smoke, explosion hazard, etc.), or otherwise requires the equipment, personnel, resources, and/or expertise of a fire brigade. Typically, a fire extinguisher consists of a hand-held cylindrical pressure vessel containing an agent that can be discharged to extinguish a fire. Fire extinguishers manufactured with non-cylindrical pressure vessels also exist but are less common. There are two main types of fire extinguishers: stored-pressure and cartridge-operated. In stored pressure units, the expellant is stored in the same chamber as the firefighting agent itself. Depending on the agent used, different propellants are used. With dry chemical extinguishers, nitrogen is typical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylation
In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These terms are commonly used in chemistry, biochemistry, soil science, and the biological sciences. In biological systems, methylation is catalyzed by enzymes; such methylation can be involved in modification of heavy metals, regulation of gene expression, regulation of protein function, and RNA processing. In vitro methylation of tissue samples is also one method for reducing certain histological staining artifacts. The reverse of methylation is demethylation. In biology In biological systems, methylation is accomplished by enzymes. Methylation can modify heavy metals, regulate gene expression, RNA processing and protein function. It has been recognized as a key process underlying epigenetics. Methanogenesis Methanogenesis, the process th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bermuda Grass
''Cynodon dactylon'', commonly known as Bermuda grass, is a grass found worldwide. It is native to Europe, Africa, Australia and much of Asia. It has been introduced to the Americas. Although it is not native to Bermuda, it is an abundant invasive species there. In Bermuda it has been known as "crab grass" (also a name for ''Digitaria sanguinalis''). It is also known by various names as ''Dhoob'', ''dūrvā'' grass, ''ethana'' grass, ''dubo'', dog grass, dog's tooth grass, Bahama grass, crab grass, devil's grass, couch grass, Indian ''doab'', ''arugampul'', grama, wiregrass and scutch grass. Description The blades are a grey-green colour and are short, usually long with rough edges. The erect stems can grow tall. The stems are slightly flattened, often tinged purple in colour. The seed heads are produced in a cluster of two to six spikes together at the top of the stem, each spike long. It has a deep root system; in drought situations with penetrable soil, the root system ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISPM 15
International Standards For Phytosanitary Measures No. 15 (ISPM 15) is an International Phytosanitary Measure developed by the International Plant Protection Convention (IPPC) that directly addresses the need to treat wood materials of a thickness greater than 6mm, used to ship products between countries. Its main purpose is to prevent the international transport and spread of disease and insects that could negatively affect plants or ecosystems. ISPM 15 affects all wood packaging material ( pallets, crates, dunnages, etc.) and requires that they be debarked and then heat treated or fumigated with methyl bromide, and stamped or branded with a mark of compliance. This mark of compliance is colloquially known as the "wheat stamp". Products exempt from the ISPM 15 are made from an alternative material, like paper, plastic or wood panel products (i.e. OSB, hardboard, and plywood). ISPM 15 revision The Revision of ISPM No. 15 (2009) under Annex 1, requires that wood used to manu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fumigant
Fumigation is a method of pest control or the removal of harmful micro-organisms by completely filling an area with gaseous pesticides—or fumigants—to suffocate or poison the pests within. It is used to control pests in buildings (structural fumigation), soil, grain, and produce. Fumigation is also used during the processing of goods for import or export to prevent the transfer of exotic organisms. Structural fumigation targets pests inside buildings (usually residences), including pests that inhabit the physical structure itself, such as woodborers and drywood termites. Commodity fumigation, on the other hand, is also to be conducted inside a physical structure, such as a storage unit, but it aims to eliminate pests from infesting physical goods, usually food products, by killing pests within the container which will house them. Each fumigation lasts for a certain duration. This is because after spraying the pesticides, or fumigants, only the pests around are e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fallow
Fallow is a farming technique in which arable land is left without sowing for one or more vegetative cycles. The goal of fallowing is to allow the land to recover and store organic matter while retaining moisture and disrupting pest life cycles and soil borne pathogens by temporarily removing their hosts. Crop rotation systems typically called for some of a farmer's fields to be left fallow each year. The increase in intensive farming, including the use of cover crops in lieu of fallow practices, has caused a loss of acreage of fallow land, as well as field margins, hedges, and wasteland. This has reduced biodiversity; fallows have been the primary habitat for farmland bird populations. Fallow syndrome Fallow syndrome is when a crop has insufficient nutrient uptake due to the lack of arbuscular mycorhizae (AM fungi) in the soil following a fallow period. Crops such as corn that are prone to fallow syndrome should not follow a period of fallow, but instead should follow a cover ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rogueing
In agriculture, roguing refers to the act of identifying and removing plants with undesirable characteristics from agricultural fields. Rogues are removed from the fields to preserve the quality of the crop A crop is a plant that can be grown and harvested extensively for profit or subsistence. When the plants of the same kind are cultivated at one place on a large scale, it is called a crop. Most crops are cultivated in agriculture or hydroponic ... being grown. Plants being removed may be diseased, be of an unwanted variety, or undesirable for other reasons. For example, to ensure that the crop retains its integrity as regards certain physical attributes, such as color and shape, individual plants that exhibit differing traits are removed. Roguing is particularly important when growing seed crops, to prevent plants with undesirable characteristics from propagating into subsequent generations.Agricultural Seed Production By Raymond A. T. George References Agricultural pests ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Steam Sterilization
Soil steam sterilization (soil steaming) is a farming technique that sterilizes soil with steam in open fields or greenhouses. Pests of plant cultures such as weeds, bacteria, fungi and viruses are killed through induced hot steam which causes vital cellular proteins to unfold. Biologically, the method is considered a partial disinfection. Important heat-resistant, spore-forming bacteria can survive and revitalize the soil after cooling down. Soil fatigue can be cured through the release of nutritive substances blocked within the soil. Steaming leads to a better starting position, quicker growth and strengthened resistance against plant disease and pests. Today, the application of hot steam is considered the best and most effective way to disinfect sick soil, potting soil and compost. It is being used as an alternative to bromomethane, whose production and use was curtailed by the Montreal Protocol. "Steam effectively kills pathogens by heating the soil to levels that cause ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herbicides
Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page for EPA reports on pesticide use ihere Selective herbicides control specific weed species, while leaving the desired crop relatively unharmed, while non-selective herbicides (sometimes called total weedkillers in commercial products) can be used to clear waste ground, industrial and construction sites, railways and railway embankments as they kill all plant material with which they come into contact. Apart from selective/non-selective, other important distinctions include ''persistence'' (also known as ''residual action'': how long the product stays in place and remains active), ''means of uptake'' (whether it is absorbed by above-ground foliage only, through the roots, or by other means), and ''mechanism of action'' (how it works). Historica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed Production
Seed companies produce and sell seeds for flowers, fruits and vegetables to commercial growers and amateur gardeners. The production of seed is a multibillion-dollar business, which uses growing facilities and growing locations worldwide. While most of the seed is produced by large specialist growers, large amounts are also produced by small growers that produce only one to a few crop types. The larger companies supply seed both to commercial resellers and wholesalers. The resellers and wholesalers sell to vegetable and fruit growers, and to companies who package seed into packets and sell them on to the amateur gardener. Most seed companies or resellers that sell to retail produce a catalog, for seed to be sown the following spring, that is generally published during early winter. These catalogs are eagerly awaited by the amateur gardener, as during winter months there is little that can be done in the garden so this time can be spent planning the following year’s gardening. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
