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Decafluorobutane
Perfluorobutane (PFB) is an inert, high-density colorless gas. It is a simple fluorocarbon with a ''n''-butane skeleton and all the hydrogen atoms replaced with fluorine atoms. Uses Perfluorobutane can replace Halon 1301 in fire extinguishers, as well as the gas component for newer generation microbubble ultrasound contrast agents. Sonazoid is one such microbubble formulation developed by Amersham Health that uses perfluorobutane for the gas core. Due to its inert nature and high density, inhaling perfluorobutane makes one's voice deeper. Caution is advised as heavier gases are difficult to breathe out and may cause inert gas asphyxiation. Environmental impacts If perfluorobutane is released to the environment, it will not be broken down in air. It is not expected to be broken down by sunlight. It will move into air from soil and water surfaces. If it is exposed to conditions of extreme heat from misuse, equipment failure, etc., toxic decomposition products including hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of Chemistry
The Royal Society of Chemistry (RSC) is a learned society and professional association in the United Kingdom with the goal of "advancing the chemistry, chemical sciences". It was formed in 1980 from the amalgamation of the Chemical Society, the Royal Institute of Chemistry, the Faraday Society, and the Society for Analytical Chemistry with a new Royal Charter and the dual role of learned society and professional body. At its inception, the Society had a combined membership of 49,000 in the world. The headquarters of the Society are at Burlington House, Piccadilly, London. It also has offices in Thomas Graham House in Cambridge (named after Thomas Graham (chemist), Thomas Graham, the first president of the Chemical Society) where ''RSC Publishing'' is based. The Society has offices in the United States, on the campuses of The University of Pennsylvania and Drexel University, at the University City Science Center in Philadelphia, Pennsylvania, in both Beijing and Shanghai, People' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbubbles
Microbubbles are bubbles smaller than one hundredth of a millimetre in diameter, but larger than one micrometre. They have widespread application in industry, medicine, life science, and food technology. The composition of the bubble shell and filling material determine important design features such as buoyancy, crush Mechanical strength, strength, thermal conductivity, and acoustic properties. They are used in medical diagnostics as a contrast agent for ultrasound imaging. The gas-filled microbubbles, typically air or perfluorocarbon, oscillate, and vibrate if a sonic energy field is applied and may reflect ultrasound waves. This distinguishes the microbubbles from surrounding tissues. Because gas bubbles in liquid lack stability and would therefore quickly dissolve, microbubbles are typically encapsulated by shells. The shell is made from elastic, viscoelastic, or viscous material. Common shell materials are lipid, albumin, and protein. Materials having a hydrophilic outer layer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfluoroalkanes
Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often have distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Several fluorocarbons and their derivatives are commercial polymers, refrigerants, drugs, and anesthetics. Nomenclature Perfluorocarbons or PFCs, are organofluorine compounds with the formula CxFy, meaning they contain only carbon and fluorine. The terminology is not strictly followed and many fluorine-containing organic compounds are also called fluorocarbons. Compounds with the prefix perfluoro- are hydrocarbons, including those with heteroatoms, wherein all C-H bonds have been replaced by C-F bonds. Fluorocarbons includes perfluoroalkanes, fluoroalkenes, fluoroalkynes, and perfluoroaromatic compounds. Perfluoroalkanes Chemical properties Perfluoroalkanes are very stable because of the strength of the carbon–fluorine bond, one of the strongest in organic chemistry. Its stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozone Depletion Potential
The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with trichlorofluoromethane (R-11 or CFC-11) being fixed at an ODP of 1.0. Chlorodifluoromethane (R-22), for example, has an ODP of 0.05. CFC 11, or R-11 has the maximum potential amongst chlorocarbons because of the presence of three chlorine atoms in the molecule. The first proposal of ODP came from Wuebbles in 1983. It was defined as a measure of destructive effects of a substance compared to a reference substance. Precisely, ODP of a given substance is defined as the ratio of global loss of ozone due to the given substance to the global loss of ozone due to CFC-11 of the same mass. ODP can be estimated from the molecular structure of a given substance. Chlorofluorocarbons have ODPs roughly equal to 1. Brominated substances have usually higher ODPs in range 5–15, because of the more aggressive bromine reaction with ozone. Hydrochlorofluorocar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Warming Potential
Global warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere over a specific time period, relative to carbon dioxide (). It is expressed as a multiple of warming caused by the same mass of carbon dioxide (). Therefore, by definition has a GWP of 1. For other gases it depends on how strongly the gas absorbs thermal radiation, how quickly the gas leaves the atmosphere, and the time frame considered. For example, Methane emissions, methane has a GWP over 20 years (GWP-20) of 81.2. meaning that, a Fugitive gas emissions, leak of a tonne of methane is equivalent to emitting 81.2 tonnes of carbon dioxide measured over 20 years. As methane has a much shorter atmospheric lifetime than carbon dioxide, its GWP is much less over longer time periods, with a GWP-100 of 27.9 and a GWP-500 of 7.95. The carbon dioxide equivalent (e or eq or -e or -eq) can be calculated from the GWP. For any gas, it is the mass of that would warm the earth as much as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Fluoride
Hydrogen fluoride (fluorane) is an Inorganic chemistry, inorganic compound with chemical formula . It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers such as polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils near room temperature, a much higher temperature than other hydrogen halides. Hydrogen fluoride is an extremely dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with moisture. The gas can also cause blindness by rapid destruction of the corneas. History In 1771 Carl Wilhelm Scheele prepared the aqueous solution, hydrofluoric acid in large quantities, although hydrofluoric acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inert Gas Asphyxiation
Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen (hypoxia), rather than atmospheric air (which is composed largely of nitrogen and oxygen). Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, helium and nitrogen. The term "physiologically inert" is used to indicate a gas which has no toxic or anesthetic properties and does not act upon the heart or hemoglobin. Instead, the gas acts as a simple diluent to reduce the oxygen concentration in inspired gas and blood to dangerously low levels, thereby eventually depriving cells in the body of oxygen. According to the U.S. Chemical Safety and Hazard Investigation Board, in humans, "breathing an oxygen deficient atmosphere can have serious and immediate effects, including unconsciousness after only one or two breaths. The exposed person has no warning and cannot s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contrast-enhanced Ultrasound
Contrast-enhanced ultrasound (CEUS) is the application of ultrasound contrast medium to traditional medical sonography. Ultrasound contrast agents rely on the different ways in which sound waves are reflected from interfaces between substances. This may be the surface of a small air bubble or a more complex structure. Commercially available contrast media are gas-filled microbubbles that are administered intravenously to the systemic circulation. Microbubbles have a high degree of echogenicity (the ability of an object to reflect ultrasound waves). There is a great difference in echogenicity between the gas in the microbubbles and the soft tissue surroundings of the body. Thus, ultrasonic imaging using microbubble contrast agents enhances the ultrasound backscatter, (reflection) of the ultrasound waves, to produce a sonogram with increased contrast due to the high echogenicity difference. Contrast-enhanced ultrasound can be used to image blood perfusion in organs, measure blood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Industrial Chemicals Notification And Assessment Scheme
The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) was the Australian government's regulatory body for industrial chemicals until 2020. NICNAS was designed to help protect workers, the public and the environment from the harmful effects of industrial chemicals. It made risk assessment and safety information on chemicals widely available and providing recommendations for their safe use. NICNAS also informed importers and manufacturers of their legal responsibilities. In 2020, it was replaced by the Australian Industrial Chemicals Introduction Scheme (AICIS). History Despite an extensive history of chemical manufacture, use, import and export, it was not until the advancement in manufacturing technologies and processes in the mid 20th century that the value of chemical assessment and regulation was fully realised. Industrial chemical assessment and regulation is still a relatively new phenomenon for many governments including Australia because, prior to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Adopted Name
A United States Adopted Name (USAN) is a unique nonproprietary name assigned to a medication marketed in the United States. Each name is assigned by the USAN Council, which is co-sponsored by the American Medical Association (AMA), the United States Pharmacopeial Convention (USP), and the American Pharmacists Association (APhA). The USAN Program states that its goal is to select simple, informative, and unique nonproprietary names (also called generic names) for drugs by establishing logical nomenclature classifications based on pharmacological or chemical relationships. In addition to drugs, the USAN Council names agents for gene therapy and cell therapy, contact lens polymers, surgical materials, diagnostics, carriers, and substances used as an excipient. The USAN Council works in conjunction with the World Health Organization (WHO) international nonproprietary name (INN) Expert Committee and national nomenclature groups to standardize drug nomenclature and establish rule ... [...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 or expertise of a fire brigade. Typically, a fire extinguisher consists of a hand-held cylindrical pressure vessel containing an #Types of extinguishing agents, 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 extingu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halon 1301
Bromotrifluoromethane, commonly referred to by the code numbers Halon 1301, R13B1, Halon 13B1 or BTM, is an organic halide with the chemical formula carbon, Cbromine, Brfluorine, F3. It is used for gaseous fire suppression as a far less toxic alternative to bromochloromethane. Table of physical properties Synthesis Bromotrifluoromethane is commercially synthesized in a two-step process from chloroform. Chloroform is fluorinated with hydrogen fluoride. CHCl3 + 3 HF → CHF3 + 3 HCl The resulting Fluoroform is then reacted with elemental bromine. CHF3 + Br2 → CF3Br + HBr Uses Halon 1301 was developed in a joint venture between the U.S. Army and Purdue University in the late 1940's, and became a DuPont product in 1954. It was introduced as an effective gaseous fire suppression fixed systems agent in the 1960s, and was used around valuable materials, such as aircraft, Mainframe computer, mainframe computers, and telecommunication telephone exchange, switching centers, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
