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Aerosol Mass Spectrometry
Aerosol mass spectrometry is the application of mass spectrometry to the analysis of the composition of aerosol particles. Aerosol particles are defined as solid and liquid particles suspended in a gas (air), with size range of 3 nm to 100 μm in diameter and are produced from natural and anthropogenic sources, through a variety of different processes that include wind-blown suspension and combustion of fossil fuels and biomass. Analysis of these particles is important owing to their major impacts on global climate change, visibility, regional air pollution and human health. Aerosols are very complex in structure, can contain thousands of different chemical compounds within a single particle, and need to be analysed for both size and chemical composition, in real-time or off-line applications. Off-line mass spectrometry is performed on collected particles, while on-line mass spectrometry is performed on particles introduced in real time. History In literature from ancient R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WB-57 PALMS Mount
The Martin B-57 Canberra is an American-built, twin-engined Tactical bombing, tactical bomber and reconnaissance aircraft that entered service with the United States Air Force (USAF) in 1953. The B-57 is a license-built version of the British English Electric Canberra, manufactured by the Glenn L. Martin Company. Initial Martin-built models were virtually identical to their British-built twinjet counterparts; Martin later modified the design to incorporate larger quantities of US-sourced components and produced the aircraft in several different variants. The B-57 Canberra holds the distinction of being the first jet bomber in U.S. service to drop bombs during combat. The Canberra was used extensively during the Vietnam War in a bombing capacity; dedicated versions of the type were also produced and served as high-altitude aerial reconnaissance platforms (the Martin RB-57D Canberra), and as electronic warfare aircraft. The B-57 Canberra was also sold to export customers abroad; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrospray Ionization
Electrospray ionization (ESI) is a technique used in mass spectrometry to produce ions using an electrospray in which a high voltage is applied to a liquid to create an aerosol. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. ESI is different from other ionization processes (e.g. matrix-assisted laser desorption/ionization (MALDI)) since it may produce multiple-charged ions, effectively extending the mass range of the analyser to accommodate the kDa-MDa orders of magnitude observed in proteins and their associated polypeptide fragments. Mass spectrometry using ESI is called electrospray ionization mass spectrometry (ESI-MS) or, less commonly, electrospray mass spectrometry (ES-MS). ESI is a so-called 'soft ionization' technique, since there is very little fragmentation. This can be advantageous in the sense that the molecular ion (or more accurately a pseudo molecular ion) is almost alw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Spectrometry
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a type of plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds. In a typical MS procedure, a sample, which may be solid, liquid, or gaseous, is ionized, for example by bombarding it with a beam of electrons. This may cause some of the sample's molecules to break up into positively charged fragments or simply become positively charged without fragmenting. These ions (fragments) are then separated accordin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Size Analysis
Particle size analysis, particle size measurement, or simply particle sizing, is the collective name of the technical procedures, or laboratory techniques which determines the size range, and/or the average, or mean size of the particles in a powder or liquid sample. Particle size analysis is the part of particle science, and it is generally carried out in particle technology laboratories. The particle size measurement is typically achieved by means of devices, called Particle Size Analyzers (PSA), which are based on different technologies, such as high definition image processing, analysis of Brownian motion, gravitational settling of the particle and light scattering ( Rayleigh and Mie scattering) of the particles. The particle size can have considerable importance in a number of industries including the chemical, food, mining, forestry, agriculture, cosmetics, pharmaceutical, energy, and aggregate industries. Particle size analysis based on light scattering Particle siz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerosol Impaction
In the physics of aerosols, aerosol impaction is the process in which particles are removed from an air stream by forcing the gases to make a sharp bend. Particles above a certain size possess so much momentum that they can not follow the air stream and strike a collection surface, which is available for later analysis of mass and composition. Removal of particles from an air-stream by impaction followed by mass and composition analysis has always been a different approach as to filter sampling, yet has been little utilized for routine analysis because of lack of suitable analytical methods. Advantages The most clear and important advantage of impaction, as opposed to filtration, is that two key aerosol parameters, size and composition, can be simultaneously established. There are many advantages of impa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particulate Matter Sampler
A particulate matter sampler is an instrument for measuring the properties (such as mass concentration or chemical composition) of particulates in the ambient air. Types Two different types of particulate matter samplers exist that measure particulate mass concentration: manual samplers and automated samplers. Manual Manual samplers draw a known volume of air through a filter. The filter is weighed on an analytical balance before and after sampling, and the difference in weight divided by the volume of air pulled through the filter gives the mass concentration of the particulate. Automated Automated samplers do the weighing in the field. There are two types of automated samplers in common usage: samplers that use a beta gauge for mass measurement and samplers that use a tapered element oscillating microbalance (TEOM) for mass measurement. Beta gauge Beta gauge particulate samplers have an appearance that is similar to a reel to reel tape recorder. Air is pulled through a f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Microprobe Mass Spectrometer
A laser microprobe mass spectrometer (LMMS), also laser microprobe mass analyzer (LAMMA), laser ionization mass spectrometer (LIMS), or laser ionization mass analyzer (LIMA) is a mass spectrometer that uses a focused laser for microanalysis. It employs local ionization by a pulsed laser and subsequent mass analysis of the generated ions. Methods In laser microprobe mass analysis, a highly focused laser beam is pulsed on a micro sample usually with a volume of approximately 1 microliter. The resulting ions generated by this laser are then analyzed with time-of-flight mass spectrometry to give composition, concentration, and in the case of organic molecules structural information. Unlike other methods of microprobe analysis which involve ions or electrons, the LMMS microproble fires an ultraviolet pulse in order to create ions. Advantages LMMS is relatively simple to operate compared to other methods. Furthermore, its strengths include its ability to analyze biological materials to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lockheed P-3 Orion
The Lockheed P-3 Orion is a four-engined, turboprop anti-submarine and maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. Lockheed based it on the L-188 Electra commercial airliner. The aircraft is easily distinguished from the Electra by its distinctive tail stinger or "MAD" boom, used for the (MAD) of submarines. Over the years, the aircraft has seen numerous design developments, most notably in its electronics packages. Nume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Douglas DC-8
The Douglas DC-8 (sometimes McDonnell Douglas DC-8) is a long-range narrow-body airliner built by the American Douglas Aircraft Company. After losing the May 1954 US Air Force tanker competition to the Boeing KC-135, Douglas announced in July 1955 its derived jetliner project. In October 1955, Pan Am made the first order along with the competing Boeing 707, and many other airlines followed. The first DC-8 was rolled out in Long Beach Airport on April 9, 1958, and flew for the first time on May 30. FAA certification was achieved in August 1959 and the DC-8 entered service with Delta Air Lines on September 18. The six-abreast, low wing airliner was a four-engined jet aircraft with initial variants being long. The DC-8-10 was powered by Pratt & Whitney JT3C turbojets and had a MTOW, the DC-8-20 had more powerful JT4A turbojets for a MTOW. The intercontinental models had more fuel capacity and up to MTOW, powered by JT4As for the Series 30 and by Rolls-Royce Conway turbof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photomultiplier
A photomultiplier is a device that converts incident photons into an electrical signal. Kinds of photomultiplier include: * Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for short) are members of the class of vacuum tubes, and more specifically vacuum phototubes, which are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. ** Magnetic photomultiplier, developed by the Soviets in the 1930s. ** Electrostatic photomultiplier, a kind of photomultiplier tube demonstrated by Jan Rajchman of RCA Laboratories in Princeton, NJ in the late 1930s which became the standard for all future commercial photomultipliers. The first mass-produced photomultiplier, the Type 931, was of this design and is still commercially produced today. * Silicon photomultiplier, a solid-state device converting incident photons into an electric signal. Silicon photomultiplie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerosol Mass Spectrometer
Aerosol mass spectrometry is the application of mass spectrometry to the analysis of the composition of aerosol particles. Aerosol particles are defined as solid and liquid particles suspended in a gas (air), with size range of 3 nm to 100 μm in diameter and are produced from natural and anthropogenic sources, through a variety of different processes that include wind-blown suspension and combustion of fossil fuels and biomass. Analysis of these particles is important owing to their major impacts on global climate change, visibility, regional air pollution and human health. Aerosols are very complex in structure, can contain thousands of different chemical compounds within a single particle, and need to be analysed for both size and chemical composition, in real-time or off-line applications. Off-line mass spectrometry is performed on collected particles, while on-line mass spectrometry is performed on particles introduced in real time. History In literature from ancient R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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