Nonreactive gases

Type SR-0 compounds include insoluble and nonreactive gases (e g., inert gases such as H2, He). These compounds do not significantly interact with the respiratory tract tissues, and essentially all compound inhaled is exhaled. Radiation doses from inhalation exposure of SR-0 compounds are assumed to result from the irradiation of the respiratory tract from the air spaces. 

The gas used to pressurize a system should be clean and dry. Nitrogen and argon are very good because they are nonreactive gases. Do not use pure oxygen, especially if there are any greasy areas in the system because an explosion may result. 

The preparation of synthetic atmospheres for nonreactive gases and vapors is relatively straightforward, but the preparation of fumes, aerosols, and particulates is considerably more difficult. For purposes of industrial hygiene sampling, a polydisperse aerosol containing respirable-size particles is required. 

In this equation, the first term on the right-hand side is the flux contributed by the solution-diffusion mechanism, while the second term is due to the facilitated transport mechanism. The nonreacting gases, like H2, N2, and CO, do not have chemical association with carriers and therefore can only be transported by diffusion, which is limited by their low solubility in the highly polar sites in the membranes.16... 

For these nonreacting gases, the flux equation for the diffusion step in the membrane is the first term on the right-hand side of Equation 9.15 only. 

Behavior Mixtures of nonreacting gases behave as if only a single component were present. 

Table 14-4 indicates that all combinations of solids, liquids, and gases can form colloids except mixtures of nonreacting gases (all of which are homogeneous and, therefore, true solutions). Whether a given mixture forms a solution, a colloidal dispersion, or a suspension depends on the size of the solute-like particles (Table 14-5), as well as solubility and miscibility. 

In the manufacture of electronics components such as vacuum tubes or light bulbs, brazing (a process in which materials are heat-bonded) is carried out either in a hydrogen atmosphere or in nonreactive gases (such as argon or nitrogen) to prevent oxidization. 

The experimental determination of A quenching is difficult because of its great stability. In most flow systems the decay is largely on the walls of the vessel where it can suffer about 2 X 10 collisions before deactivation. Collisions with most other molecules are even less effective. At the moment it can only be said that more than 10 collision with Oo X) are necessary to deactivate A. Other, nonreactive gases cannot be tested simply because so much must be added that it radically affects the flow system and discharge, making the measurements difficult to interpret. 

Active species are formed in the plasma from nonreactive gases. 

Gases such as Nj, Oj, NH3, COj, Hj, HjO, carbon monoxide, nitrogen dioxide, and nitric oxide are thought to be reactive in plasmas. The mechanism of their action is the same as for nonreactive gases—the surface is bombarded with ionized plasma components to generate radical sites. These subsequently react with gas molecules, creating various functionalities, depending on the plasma conditions. 

Gotoh (19) determined theoretically the solubilities of nonreacting gases in liquids from the free theory. 

As noted earlier in the context of Tables 20.4-1, 20.4-2, and 20.4-3, the ratio of pure component permeabilities at an arbitrary pressure is a useful indication of the selectivity of a candidate nnembrane for the chosen gas pair. Never less, because of a variety of factors, the actual selectivity and productivity observed in the mixed gas case may be somewhat different than predicted on the basis of the pure eomponent data. One of these factors, illustrated in Fig. 20.4-4, is important for low- and interr iate-pressure applications and is believed to be due to competition by mixture components for unrelaxed molecular-scale gaps between glassy-polymer chain segments. As shown in the left-hand side of the figure, the presence of a second component B can depress the observed permeability of a component A relative to its pure component value at a given upstream driving pressure of component A. H< n and coworkers note that the permeability of a membrane to a component A may be reduced due to the sorption of a second component B in the polymer which ... effectively reduces the microvoid content of the film and the available diffiision paths for the nonreactive gases. ... 

In the case of nonreactive gases, denoted by subscript g, an empirical manner of looking at the salting-out has been proposed by Weisenberger and Schumpe [12] by means of the expression ... 

Collision mechanisms using nonreactive gases and kinetic energy discrimination (KED)... 

CoLLisiONAL Mechanisms Using Nonreactive Gases AND Kinetic Energy Discrimination... 

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