Types of emissions

Induced, or stimulated, emission. This is a different type of emission process from that of type 2 in that a quantum of radiation of wavenumber v given by Equation (2.2) is required to induce, or stimulate, M to go from n to m. The process is represented by... 

Control technology requirements vary according to the scale of operation and type of emission problem. For instance, electrostatic precipitator design requirements for fly-ash control from 1000-MW coal-fired power boilers differ from those for a chemical process operation. In the discussion that follows, priority is given to control technology for the CPI as opposed to the somewhat special needs of other industries. 

The methods for detection and quantitation of radiolabeled tracers are deterrnined by the type of emission, ie, y-, or x-rays, the tracer affords the energy of the emission and the efficiency of the system by which it is measured. Detection of radioactivity can be achieved in all cases using the Geiger counter. However, in the case of the radionucHdes that emit low energy betas such as H, large amounts of isotopes are required for detection and accurate quantitation of a signal. This is in most cases undesirable and impractical. Thus, more sensitive and reproducible methods of detection and quantitation have been developed. 

Types of Dia.gnostic Isotopes. Isotopes used in nuclear medicine may be characterized by the source used to produce the radioactive isotope, by whether the isotopes are produced at a central location and shipped or at the clinic, or by the type of emission and thus the equipment used to detect them. The first of these, the sources, are summarized in Table 2. Some isotopes may be produced by more than one method. 

The air stream exiting a stripper may requite some type of emissions control, depending on local and regulatory requirements. Carbon adsorption is often used catalytic oxidation is another option. 

Important atmospheric pollutants comprise smoke, dust, grit, fumes and gases. Types of emission are shown in Table 16.9. 

Shottky Emission - This is also a thermionic type of emission except that in this case, the applied electric field effectively decreases the work function of the material, and more electrons can then escape. 

Based on the manufacturing process, the existing emission processes, and on workers demands (e.g., ergonomical aspects), different types of booths are possible. Many of these are commonly used. There can be a division according to the booth type (the shape of the booth), the position of the worker, the type of emission process, and the applied types of capture devices with the corresponding airflow pattern inside the booth. 

The position of the worker could be inside or outside the booth. In some ca.ses, the worker is no longer necessary because of automation. The essential types of emission processes are described in the Design Equations and/or Parameters section. 

Finally, knowing tlie quantity and type of emissions released by power plant stacks does not provide enough information to estimate tlie e.xposure of individuals to tliese substances. 

Boilers and most industrial furnaces have performance standards that they must meet. For each category or type of emission, the regulations establish compliance methods and alternatives. 

BIFs are required to comply with strict air emission standards to ensure adequate protection of human health and the environment. These standards are divided into four contaminant categories organics, PM, metals, and HC1 and chlorine (Cl2). For each category or type of emission, the regulations establish compliance methods and alternatives. Each is addressed in Table 23.3. 

There are many types of emissions to atmosphere, and these can be characterized as particulate (solid or liquid), vapor and gaseous. Overall, the control of atmospheric emissions is difficult because the majority of emissions come from small sources that are difficult to regulate and control. Legislators therefore control emissions from sources that are large enough to justify monitoring and inspection. Industrial emissions of major concern are as follows. 

This type of emission estimates can be included in LCAs to make them more complete. 

Generally speaking, luminescence spectra (fluorescence and phosphorescence) provide more information about excited states than do absorption spectra. This is because luminescence measurements are much more sensitive than absorption measurements, and the two types of emission can be studied separately due to their widely differing lifetimes. 

In acetonitrile-dichloromethane 1 1 v/v solution, their absorption spectra are dominated by naphthalene absorption bands and they exhibit three types of emission bands, assigned to naphthyl localized excited states (/Wx = 337 nm), naphthyl excimers (Amax ca. 390 nm), and naphthyl-amine exciplexes (/lmax = 480 nm) (solid lines in Fig. 3). The tetraamine cyclam core undergoes only two protonation reactions, which not only prevent exciplex formation for electronic reasons but also cause strong nuclear rearrangements in the cyclam structure which affect excimer formation between the peripheral naphthyl units of the dendrimers. 

Hi) Line Spectra Line spectra are usually encountered when the light emitting substance i.e., the radiating species are separate atomic entities (particles) which are distinctly separated from one another, as in gas. Therefore, it is invariably known as atomic spectrum . As the line spectrum depends solely upon the type of an atom, hence it enjoys the status of a predominant type of emission spectroscopy. 

In addition, the quenching of the fluorescence of fluorophore groups in protein molecules by neighboring groups(35) and its temperature dependence, t36) energy transfer of electronic excitation and its dependence on excitation wavelength,(1) the type of emission decay kinetics,(1,2) and changes... 

However, it is not our intent in this chapter to enter into a political discussion of the levy of fines for infringement of the environmental laws. Our purpose is to provide the reader with an overview of a selection of the many and varied regulations that shows the types of emissions from refinery processes and the laws that regulate these emissions. 

Recently the protection of the environment has become increasingly important for industry with the requirement that the potential impact on the environment is considered for all aspects of industrial processes. Such considerations are supported by environmental legislation that controls all types of emissions as well as the treatment of wastes. Such legislation is based on global standards that have largely resulted from developments within the European Union, Japan, and the United States in collaboration with international conventions. Of these, the Basel Convention (1989) and the Earth Summit in Rio de Janeiro (1992) were significant in the control and prevention of wastes. In the case of liquid wastes that are most appropriate for treatment by liquid liquid extraction, limits for discharge into the aqueous environment have been established by the three countries already mentioned. These limits depend on the particular country and sometimes on the industry. (See section 14.6.)... 

When stressed, a material releases various types of emission prior to, during, and subsequent to ultimate failure. This emission includes electrons, positive ions, neutral molecules, and photons - including long wavelength electromagnetic radiation (radio waves), which we have collectively termed fracto-emission (FE). 

This type of emission control system has been in use in limited volumes in California since the 1977 model year, on nearly all California cars in the 1980 model year, and will apparently be on a majority of cars in this country in the 1981 model year. No other method has been nearly as effective in meeting the federally mandated emission requirements without severe penalties in performance and/or fuel economy. 

Four types of emissions related to distance from a sampling site are compiled using standard emissions factors where applicable. Pace investigated many other variables in multiple linear regressions with TSP but found these to be the significant ones. 

The samples were analyzed for trace metals and sulfate as well as for three fractions of particulate organic matter (POM) using sequential extraction with cyclohexane (CYC), dichloromethane (DCM) and acetone (ACE). Factor analysis was used to identify the principal types of emission sources and select source tracers. Using the selected source tracers, models were developed of the form POM = a(V) + b(Pb) + - - -, where a and b are regression coefficients determined from ambient data adjusted to constant dispersion conditions. The models for CYC and ACE together, which constitute 90% of the POM, indicate that 40% (3.0 pg/m ) of the mass was associated with oil-burning, 19% (1.4 pg/m ) was from automotive and related sources and 15% (1.1 pg/m ) was associated with soil-like particles. 

Factor analysis was used to identify principal types of emission sources and to select elemental source tracers. As factor analysis has been described in detail in the literature (10-13), only a general description of the technique will be given... 

TABLE 10.22 Average ( +S9 and — S9) and Highest (— S9) Values of Mutagenicityb (rev m 3) of Ambient Particles Collected1 at Seven Cities/ Sites in California 1 with Different Types of Emission Sources"... 

FIGURE 10.22 Direct mutagenicity of ambient particles (mutagen density, rev m-3, TA98, —S9) as a function of ambient concentrations of 2-nitropyrene, a directly mutagenic product of a gas-phase atmospheric reaction initiated by OH radical attack on pyrene. Samples collected at six sites in California with different types of emissions ( ) Glendora (O) Yuba City ( ) Concord ( ) Mammoth Lakes ( a ) Oildale ( ) Reseda (see Fig. 10.22) (adapted from Atkinson et al., 1988a). 

Electroluminescence. In Section 6.3.2.5, we saw that some materials—in particular, semiconductors—can reemit radiation after the absorption of light in a process called photoluminescence. A related type of emission process, which is common in polymer-based semiconductors, called electroluminescence, results when the electronic excitation necessary for emission is brought about by the application of an electric field rather than by incident photons. The electric field injects electrons into the conduction band, and holes into the valence band, which upon recombination emit light. 

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