PSD

DIET Desorption induced by electronic transitions [147a] General class of desorption and reaction phenomena induced by electron or photon bombardment Same as ESD and PSD... 

PSD Photon-stimulated desorption [149, 162-165] Incident photons eject adsorbed molecules Desorption mechanisms and dynamics... 

An electron or photon incident on a surface can induce an electroiuc excitation. When the electroiuc excitation decays, an ion or neutral particle can be emitted from the surface as a result of the excitation. Such processes are known as desorption induced by electroiuc transitions (DIET) [82]. The specific teclmiques are known as electron-stimulated desorption (ESD) and photon-stimulated desorption (PSD), depending on the method of excitation. 

The protein sequence database is also a text-numeric database with bibliographic links. It is the largest public domain protein sequence database. The current PIR-PSD release 75.04 (March, 2003) contains more than 280 000 entries of partial or complete protein sequences with information on functionalities of the protein, taxonomy (description of the biological source of the protein), sequence properties, experimental analyses, and bibliographic references. Queries can be started as a text-based search or a sequence similarity search. PIR-PSD contains annotated protein sequences with a superfamily/family classification. 

Figure 9.25 (a) A Doppler-limited line, (b) The detection. V, potential psd, phase-sensitive detector... 

Other techniques in which incident photons excite the surface to produce detected electrons are also Hsted in Table 1. X-ray photoelectron Spectroscopy (xps), which is also known as electron spectroscopy for chemical analysis (esca), is based on the use of x-rays which stimulate atomic core level electron ejection for elemental composition information. Ultraviolet photoelectron spectroscopy (ups) is similar but uses ultraviolet photons instead of x-rays to probe atomic valence level electrons. Photons are used to stimulate desorption of ions in photon stimulated ion angular distribution (psd). Inverse photoemission (ip) occurs when electrons incident on a surface result in photon emission which is then detected. 

Filler particle si2e distribution (psd) and shape affect rheology and loading limits of filled compositions and generally are the primary selection criteria. On a theoretical level the influence of particle si2e is understood by contribution to the total energy of a system (2) which can be expressed on a unit volume basis as ... 

The external surface area of the filler can be estimated from a psd by summing the area of all of the equivalent spheres. This method does not take into account the morphology of the surface. It usually yields low results which provide Htde information on the actual area of the filler that induences physical and chemical processes in compounded systems. In practice, surface area is usually determined (5) from the measured quantity of nitrogen gas that adsorbs in a monolayer at the particle surface according to the BET theory. From this monolayer capacity value the specific surface area can be determined (6), which is an area per unit mass, usually expressed in m /g. 

For large amounts of fillers, the maximum theoretical loading with known filler particle size distributions can be estimated. This method (8) assumes efficient packing, ie, the voids between particles are occupied by smaller particles and the voids between the smaller particles are occupied by stiH smaller particles. Thus a very wide filler psd results in a minimum void volume or maximum packing. To get from maximum packing to maximum loading, it is only necessary to express the maximum loading in terms of the minimum amount of binder that fills the interstitial voids and becomes adsorbed on the surface of the filler. 

Optical. The optical properties of fillers and the influence that fillers have on the optical properties of filled systems are often misunderstood. The key parameters in understanding the optical properties of fillers themselves are filler psd, color, and index of refraction. These characteristics influence the optical properties of filled composition, such as color, brightness, opacity, hiding power, and gloss. 

Hardness. The hardness (qv), or related property abrasiveness, is an important filler property. Hardness is determined by comparison to materials of known hardness on the Mohs scale. On this nonlinear scale, diamond is rated 10, quartz 7, calcite 3, and talc 1. The abrasiveness of a filler is also dependent on psd and the presence of impurities, eg, ka olin clay (Mohs hardness of 3) can be quite abrasive because of the presence of quartz impurities. 

Tack. Tack causes layers to adhere when they are pressed together. This property can be reduced by employing fillers with a finer psd or by dusting the stock with a laminar filler such as mica. In a related value, fillers such as mica can inhibit adhesion to the mold during processing. 

Prevention of Significant Deterioration. EPA originally issued regulations for Prevention of Significant Deterioration (PSD) in December 1974 to protect clean air areas. Three air quaUty classes were designated Class I to protect pristine areas. Class II to allow moderate development, and Class III to permit more intensive development. Most areas in the United States were initially designated as Class II. Many large national parks and wildlife areas have been classified as Class I. 

As part of the PSD review, the appHcant must show that BACT has been appHed to ah. sources. Items to be evaluated include energy, environmental, economic, and other costs associated with each alternative technology as weU as the associated benefits of reduced emissions. Another requirement is an ambient air quaUty analysis to show that the new emissions do not exceed either the NAAQS or PSD increments. 

Position Sensitive Detectors. By replacing the scintillation detector in a conventional powder diffractometer with a Position Sensitive Detector (PSD), it is possible to speed data collection. For each x-ray photon received a PSD records the angle at which it was detected. Typically, a conventional scintillation detector records x-ray photons in a range of a few hundredths of a degree at a time. A PSD can measure many degrees (in 20) of a powder pattern simultaneously. Thus, for small samples, data collection, which could require hours with a conventional detector, could take minutes or even seconds with a PSD. 

COD Chemical oxygen demand PSD Prevention of significant deterioration... 

Prevention of Significant Deterioration (PSD) Of aU the federal laws placing environmental controls on industiy (and, in particular, on new plants), perhaps the most confusing and restrictive are the limits imposed for the prevention of significant deterioration (PSD) of air quahty. These limits apply to areas of the countiy that are already cleaner than required by ambient air-quality standards. This regula-toiy framework evolved from judicial and administrative ac tion under the 1970 Clean Air Act and subsequently was given full statutoiy foundation by the 1977 Clean Air Act Amendments. 

Sources Subject to Prevention of Significant Deterioration (PSD) Sources subject to PSD regulations (40 CFR, Sec. 52.21, Aug. 7, 1980) are major stationary sources and major modifications located in attainment areas and unclassified areas. A major stationaiy source was defined as any source hsted in Table 25-4 with the potential to emit 100 tons per year or more of any pollutant regulated under the Clean Air Act (CAA) or any other source with the potential to emit 250 tons per year or more of any CAA pollutant. The potential to emit is defined as the maximum capacity to emit the pollutant under apphcable emission standards and permit conditions (after apphcation of any air pollution control equipment) excluding secondaiy emissions. A major modification is defined as any physical or operational change of a major stationaiy source producing a significant net emissions increase of any CAA pollutant (see Table 25-5). 

TABLE 25-3 Prevention of Significant Deterioration (PSD) Air-Quality Increments... 

TABLE 25-4 Sources Subject to PSD Regulation if Their Potential to Emit Equals or Exceeds 100 Tons per Year... 

A full PSD review would include a case-by-case determination of the controls required by BACT, an ambient air-impacd analysis to determine whether the source might violate applicable increments or air-quahty standards an assessment of the effecd on visibihty soils, and vegetation submission of monitoring data and full public review. 

Bubble Policy The bubble concept introduced under PSD provisions of the Clean Air Act Amendments of 1977 was formally proposed as EPA policy on Jan. 18, 1979, the final policy statement being issued on Dec. 11, 1979. The bubble pohcy allows a company to find the most efficient way to control a plant s emissions as a whole rather than by meeting individual point-source requirements. If it is found less expensive to tighten control of a pollutant at one point and relax controls at another, this woiild be possible as long as the total pollution from the plant woiild not exceed the sum of the current hmits on individual point sources of pollution in the plant. Properly apphed, this approach would promote greater economic efficiency and increased technological innovation. 

Much of the current activity in the field of solid-waste management, especially with respect to hazardous wastes and resources recoveiy, is a direc t consequence of legislation. It is imperative to have a working knowledge of waste regulations, including RCRA (for EPA hazardous waste) TSCA (Toxic Substances Control Act) for PCBs and toxic waste Sohd Waste Disposal Act the Clean Air Ac t and PSD (prevention of... 

As a guide, because of convection that occurs from hot surfaces, ignition by a hot surface in open air should not be assumed unless the surface temperature is at least 200°C above the published minimum autoignition temperature (American Petroleum Institute, Ignition Risk of Hot Sui faces, API PSD 2216, Washington, 1980). 

Does the facility have a prevention of significant deterioration (PSD) permit ... 

Comparison of Pollutant Standard Index (PSD Values, Pollutant Levels, and General Health Effects... 

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