Effect of Gases

Parenteral products should be formulated to possess sufficient buffer capacity to maintain proper product pH. Factors that influence pH include product degradation, container and stopper effects, diffusion of gases through the closure, and the effect of gases in the product or in the headspace. However, the buffer capacity of a formulation must be readily overcome by the biological fluids thus, the concentration and ratios of buffer ingredients must be carefully selected. 

Weissbecker, L., R. D. Carpenter, P. C. Luchsinger, and T. S. Osdene. In vitro alveolar macrophage viability. Effect of gases. Arch. Environ. Health 18 756-759, 1%9. 

Another class of toroidal NMR probes is formed by toroid cavity detectors (TCD) [31]. These TCD have been mounted into cylindrical metallic autoclaves to study spin relaxation effects of gases under pressure [31]. If the toroid cavity detector is the metallic pressure vessel itself it is called a toroid cavity autoclave (TCA) probe [32, 33]. These probes can be tuned to higher resonance frequencies than TCDs and also show better spectral resolution [29]. Figure 2.12 shows the design of a TCA where the autoclave body is built from phosphorus bronze [33] keeping the field distortions of the magnetic field Bq, induced by susceptibility mismatches... 

Young men often tend to be foolhardy and Davy, performing a series of risky experiments, was no exception. For example, in order to determine the effects of gases on human beings, he inhaled them. Once he inhaled nitric oxide, even though he knew that nitric acid was formed when the substance came into contact with moist air. Not surprisingly, he burned his mouth and larynx and probably also his lungs. Another time he inhaled water gas, a combination of... 

The interpretation, of the diffraction effects of gases of simple molecular structure is simplified by the fact that the molecules are very far apart, and therefore it is necessary to consider only the distances between the atoms in one molecule. Much information on the structures of molecules has been gained in this way by Debye and others. The subject is well treated in a book by Pirenne (1946). 

There do not appear to be any general standard methods for effect of gases, and for any particular gas and product a specialised test would need to be devised. For vapours or gases fairly readily obtainable in the liquid state, the liquid is often used, but for other gases it is necessary to devise ad hoc tests using an exposure chamber through which the gas is circulated. The... 

Stieb DM, Judek S, Burnett RT (2002) Meta-analysis of time-series studies of air pollution and mortality Effects of gases and particles and the influence of causes of death, age, and season. J Air Waste Manage Assoc, 52 470-484. 

Kuri, Z, H. Ueda, and S. Schida Effects of gases on irradiated polyvinylchloride as studied by electron spin resonance. J. Chem. Phys. 32, 371 (1960). 

Ueda, H., Z. Kuri, and S. Schida Effect of gases on the electron spin resonance spectra of irradiated acrylamide and methacrylamide. T. Polymer Sci. 56, 251 (1962). 

The effect of gases on the oxide-covered germanium surface has been extensively studied over the past few years. The oxide-covered surface is usually produced by means of an aqueous etch. It is not stable in air, but changes rapidly during the first day and somewhat more slowly thereafter. Its structure and chemical composition are unknown and its thickness may vary from a few angstroms to as many as a hundred. 

In accordance with the observation that the anti-microbial effect of gases like nitrogen dioxide, carbon dioxide or xenon can be related to the effects of general anaesthetics, it seems natural to relate the well-knovm anti-microbial effect of cationic surfactants to local anaesthetic agents. The first type of perturbants shifts the actual transition in the direction La - whereas the second t)rpe of agent is expected to shift the transition in the opposite direction. It should be mentioned that quaternary ammonium surfactants such as cetyltrimethyl ammonium bromide in micellar solution in water were found to transform the cubic phase into the La phase [34]. 

Calbi, M.M. and Cole, M.W. (2002). Dimensional crossover and quantum effects of gases adsorbed on nanotube bundles. Phys. Rev. B, 66, 115413-1—12. 

Figure 1. System used for studying the effects of gases on N2(AS%U+)...

Metamorphic rocks were formed by a secondary conversion of igneous and sedimented rocks, due to certain geological tectonic processes. The pressure, temperature, and chemical effects, particularly effects of gases and thermal solutions were the main factors in these conversions. The texture of metamorphic rocks may be characterized by the presence of layers or scales. Typical metamorphic rocks are gneisses, mica-schists, serpentines, crystalline limestones and crystalline dolomites. 

Absorption an irreversible chemical retention effect on surfaces, either liquid or solid. Improperly applied to the dissolution (physical effect) of gases in liquids. 

Transport, diffusion, and removal of species in the atmosphere Formation and chemistry of clouds Interaction of atmospheric chemistry and climate Radiative and climatic effects of gases and particles... 

In comparison with the effects of liquids on plastics, very little testing is carried out on the effect of gases other than air aging tests, which were covered in the previous section of this chapter. Ozone, which is of particular concern to many elastomers (sec Chapter 15), has no special effect on most plastics, beyond the normal oxidative degradation processes, as these are fully saturated in the main. The main concern of the effect of gases is through their permeability, a subject dealt with in Chapter. 0. 

It is well known that metallic thin films of pure elements, and above all of the transition elements, are complex subjects. This comes in part from the natural gettering effect of gases which are present in the system during the preparation or in the course of the determination of the physico-chemical properties (transfer into a new atmosphere bombardment by electrons, neutrons, ions,.. annealing ...). Such a situation has been observed for rare earth, Cr, Mo, W, Ta and Bi metals for instance. One notes this is also time for the sulfurization of Au and Ag thin films in an ambient atmosphere. Many times this influences the physical properties of the materials, and often numerous discrepancies are found in the results described in the literature (Gasgnier, 1980). 

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