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Hexachloroethane
Hexachloroethane, also known as perchloroethane is the organochlorine compound with the chemical formula . It is white solid at room temperature with a camphor-like odor. It has been used by the military in smoke compositions, such as base-eject smoke munitions ( smoke grenades). Manufacture Chlorination of tetrachloroethylene at 100–140 °C with the presence of ferric chloride is the most commonly used commercial production method, however several other methods exist. A high purity form can be produced in a small scale by reacting chlorine together with barium carbide. In September 1997, it was reported as no longer being produced in the United States for commercial distribution, but was produced as a by-product of industrial chlorination process. : Applications Hexachloroethane has been used in the formulation of extreme pressure lubricants. It has also been used as a chain transfer agent in the emulsion polymerization of propylene tetrafluoroethylene copolymer. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrachloroethylene
Tetrachloroethylene, also known under the systematic name tetrachloroethene, or perchloroethylene, and many other names (and abbreviations such as "perc" or "PERC", and "PCE"), is a chlorocarbon with the formula Cl2C=CCl2 . It is a colorless liquid widely used for dry cleaning of fabrics, hence it is sometimes called "dry-cleaning fluid". It also has its uses as an effective automotive brake cleaner. It has a sweet odor detectable by most people at a concentration of 1 part per million (1 ppm). Worldwide production was about in 1985.M. Rossberg et al. "Chlorinated Hydrocarbons" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2006, Wiley-VCH, Weinheim. Production British physicist and chemist Michael Faraday first synthesized tetrachloroethylene in 1821 by thermal decomposition of hexachloroethane. :C2Cl6 → C2Cl4 + Cl2 Most tetrachloroethylene is produced by high temperature chlorinolysis of light hydrocarbons. The method is related to Faraday's discovery since hexa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Chloride
Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. This salt is hygroscopic and even deliquescent. Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn5(OH)8Cl2·H2O. Structure and properties Four crystalline forms ( polymorphs) of ZnCl2 are known: α, β, γ, and δ. Each case features tetrahedral Zn2+ centers. Here ''a'', ''b'', and ''c'' are lattice constants, ''Z'' is the number of structure units per unit cell, and ρ is the density calculated from the structure parameters. The orthorhombic form (δ) rapidly changes to one of the other forms on exposure to the atmosphere. A possible explanation is that the OH− ions originating from the absorbed water f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smoke Composition
A smoke composition is a pyrotechnic composition designed primarily to generate smoke. Smoke compositions are used as obscurants or for generation of signaling smokes. Some are used as a payload of smoke bombs and smoke grenades. Obscurants Smoke compositions used as obscurants generate large amount of thick, usually white, smoke. The most common smoke composition for pyrotechnic generation of smoke screens is the zinc chloride smoke mixture (HC). Zinc chloride smoke Zinc chloride smoke is grey-white and consists of tiny particles of zinc chloride. The most common mixture for generating these is the zinc chloride smoke mixture (HC), consisting of hexachloroethane, grained aluminium and zinc oxide. The smoke consists of zinc chloride, zinc oxychlorides, and hydrochloric acid, which absorb the moisture in the air. The smoke also contains traces of organic chlorinated compounds, phosgene, carbon monoxide, and chlorine. Its toxicity is caused mainly by the content of strongly acidi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AN M8
The AN-M8 HC Smoke Grenade designated as the Army/Navy Model 8 HC Smoke Grenade (AN-M8 Smoke HC) is a US military grenade used as a ground-to-ground obscuring or screening device or a ground-to-air signaling or target-marking device. History Developed in the 1940s, using a sheet-steel cylinder body that can emit a dense cloud of white smoke that would last from 105 to 150 seconds. The AN-M8 was used extensively by American or other allied forces throughout World War II to the 1990s. As of the September 2000 version of FM 3-23.30 ''Grenades and Pyrotechnic Signals'', the AN/M8 was listed as obsolete. Details It is used for smoke screening, target marking, and signalling, although the M18 colored smoke grenades are mainly used for the latter. Warning #The AN-M8 hand grenade produces harmful hydrochloric fumes that irritates the eyes, throat, and lungs. It should not be used in closed-in areas unless the users are wearing protective masks. #With both the AN-M8 and AN M18, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smoke Grenades
Smoke grenades used at demonstrations in Paris, 2008 upBritish L83A1 Smoke Grenade manufactured in May 2008. This grenade has already been used. A smoke grenade is a canister-type grenade used as a signaling device, target or landing zone marking device, or as a screening device for unit movements. Smoke grenades generally emit a far larger amount of smoke than smoke bombs, which are a type of fireworks typically started with an external fuse rather than a pin and are more complex. Smoke grenades often cost around compared to smoke bombs, which can often cost just a few cents. The phrase "to smoke", meaning to fake, bluff, or beat around the bush, comes from the military usage of smoke grenades to obscure and conceal movement; similarly, "pop smoke", derived from a common way of ordering the use of smoke grenades, is used as a slang term for quickly leaving a place. __TOC__ Design left, Diagram and cross section of an AN M18 smoke grenade A typical design consists of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive substances are considered carcinogens, but their carcinogenic activity is attributed to the radiation, for example gamma rays and alpha particles, which they emit. Common examples of non-radioactive carcinogens are inhaled asbestos, certain dioxins, and tobacco smoke. Although the public generally associates carcinogenicity with synthetic chemicals, it is equally likely to arise from both natural and synthetic substances. Carcinogens are not necessarily immediately toxic; thus, their effect can be insidious. Carcinogens, as mentioned, are agents in the environment capable of contributing to cancer growth. Carcinogens can be categorized into two different types: activation-dependent and activation-independent, and each nature impacts their l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occupational Safety And Health Administration
The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agency under the Occupational Safety and Health Act OSH Act, which President Richard M. Nixon signed into law on December 29, 1970. OSHA's mission is to "assure safe and healthy working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education, and assistance". The agency is also charged with enforcing a variety of whistleblower statutes and regulations. OSHA's workplace safety inspections have been shown to reduce injury rates and injury costs without adverse effects on employment, sales, credit ratings, or firm survival. History The Bureau of Labor Standards of the Department of Labor has worked on some work safety issues since its creation in 1922. Economic boom and associated l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permissible Exposure Limit
The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational Safety and Health Administration (OSHA). Most of OSHA's PELs were issued shortly after adoption of the Occupational Safety and Health (OSH) Act in 1970. For chemicals, the chemical regulation is usually expressed in parts per million (ppm), or sometimes in milligrams per cubic meter (mg/m3). Units of measure for physical agents such as noise are specific to the agent. A PEL is usually given as a time-weighted average (TWA), although some are short-term exposure limits (STEL) or ceiling limits. A TWA is the average exposure over a specified period, usually a nominal eight hours. This means that, for limited periods, a worker may be exposed to concentration excursions higher than the PEL, so long as the TWA is not exceeded and any appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parts-per Notation
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement. Commonly used are parts-per-million (ppm, ), parts-per-billion (ppb, ), parts-per-trillion (ppt, ) and parts-per-quadrillion (ppq, ). This notation is not part of the International System of Units (SI) system and its meaning is ambiguous. Overview Parts-per notation is often used describing dilute solutions in chemistry, for instance, the relative abundance of dissolved minerals or pollutants in water. The quantity "1 ppm" can be used for a mass fraction if a water-borne pollutant is present at one-millionth of a gram per gram of sample solution. When working with aqueous solutions, it is common to assume that the density of water is 1.00 g/mL. Therefore, it is common to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immediately Dangerous To Life Or Health
The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment." Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50. The Occupational Safety and Health Administration (OSHA) regulation (1910.134(b)) defines the term as "an atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere." IDLH values are often used to guide the selection of breathing apparatus that are made available to workers or firefighters in specific situations. The NIOSH definition does not include oxygen deficiency (below 19.5 percent) although atmosphere-supplying breathing appara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denver Police Department
The Denver Police Department (DPD) is the full service police department jointly for the City and County of Denver, Colorado, which provides police services to the entire county, including Denver International Airport, and may provide contractual security police service to special districts within the county. The police department is within the Denver Department of Public Safety, which also includes the Denver Sheriff Department and Denver Fire Department. The DPD was established in 1859. The current police chief is Ron Thomas. The Patrol Division is made up of 6 patrol districts. Within each patrol district, there are up to 3 different sectors. Each sector is made up of numerous precincts. Each precinct has one patrol car with 1–2 officers assigned it. Officers assigned to patrol work four 10-hour shifts. Recruits begin the DPD Academy as a recruit officer. Upon graduation, officers are classified as "police officer 4th class." After the completion of 3 years of service, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milwaukee Police Department
The Milwaukee Police Department is the police department organized under the city of Milwaukee, Wisconsin. The department has a contingent of about 1,800 sworn officers when at full strength and is divided into seven districts. Jeffrey B. Norman is the current chief of police, serving since December 2020. History MPD was founded in 1855. At the time, Milwaukee had an extremely high crime rate, fueled by local gangs, mobs, thieves and robbers. Milwaukee was originally served by the Milwaukee County Sheriff's Office, which became increasingly unable to provide adequate enforcement to the growing city. With burgeoning crime rates, citizens enacted an ordinance creating the Milwaukee Police Department. Milwaukee's first chief of police was William Beck, a former NYPD detective, and its first policemen were Fred Keppler, John Hardy, George Fische, James Rice, L.G. Ryan and David Coughlin. As the department expanded, patrolmen were supplemented by "roundsmen", who would lead the pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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