Pressure, partial dependency

Transportation is by railroad tank vehiele, by tank truek, or by pipeline. In this ease, transportation at ambient temperature is the best ehoiee. The ehoiee of storing ammonia at an ambient temperature liquid or partially refrigerated liquid or an ambient pressure liquid depends mostly on eeonomie faetors. One of the faetors that determines the storage method is the quantity of ammonia to be stored. 

In actual experiments we do not usually observe directly the desorbed amount, but rather the derived read-out quantities, as is the time dependence of the pressure in most cases. In a closed system, this pressure is obviously a monotonously increasing function of time. In a flow or pumped system, the pressure-time dependence can exert a maximum, which is a function of the maximum desorption rate, but need not necessarily occur at the same time due to the effect of the pumping speed S. If there are particles on the surface which require different activation energies Ed for their desorption, several maxima (peaks) appear on the time curve of the recorded quantity reflecting the desorption process (total or partial pressure, weight loss). Thereby, the so-called desorption spectrum arises. It is naturally advantageous to evaluate the required kinetic parameters of the desorption processes from the primarily registered read-out curves, particularly from their maxima which are the best defined points. 

The amount of hydrogen partial pressure reduction depends upon the materials and the relative thickness of the cladding/ weld overlay and the base metal—the thicker the stainless barrier is relative to the base metal the better.32 Archakov and Grebeshkova33 mathematically considered how stainless steel corrosion barrier layers increase resistance of carbon and low alloy steels to high temperature hydrogen attack. 

In general only one of these options will be preferred in a particular partial pressure regime depending upon the values of the various equilibrium constants. 

Several differences between the cobalt- and rhodium-catalyzed processes are noteworthy with regard to mechanism. Although there is a strong dependence in the cobalt system of the ethylene glycol/methanol ratio on temperature, CO partial pressure, and H2 partial pressure, these dependences are much lower for the rhodium catalyst. Details of the product-forming steps are therefore perhaps quite different in the two systems. It is postulated for the cobalt system that the same catalyst produces all of the primary products, but there seems to be no indication of such behavior for the rhodium system. Indeed, the multiplicity of rhodium species possibly present during catalysis and the complex dependence on promoters make it... 

The partial pressure Po. depends on temperature, because the equilibrium constant K is a function of temperature. It is also possible to make use of a more complex gas mixing system, such as H2O + H2, CO2 + H2, COj + CO. 

Plant/pathogen interactions in natural populations are often explained in terms of coevolution, which is the joint evolution of two (or more) taxa that have close ecological relationships but do not exchange genes, and in which reciprocal selective pressures operate to make the evolution of either taxon partially dependent upon the evolution... 

All the partial pressures calculated from the equilibrium constants assume unit activity for the condensed-phase components. This assumption is good when they are solid. Above the melting points of the salts, however, continued decomposition of the salt will result in a solution containing dissolved oxide and the partial pressures will depend on the melt composition, and will therefore change as the decomposition proceeds. Because of the form of Kt, the partial pressure calculation will be worst for small oxide concentrations. An examination of the various tables shows that 02 and NO are the major products of nitrate decomposition, the concentration of N02 being rather minor. This results from the fact that the equilibrium 2 N02 = 2 NO + 02 lies to the right for low pressures. 

Initial Species Partial Pressure—Temperature Dependence ... 

The partial pressure of each gas in a mixture of gases depends on the number of moles of that gas. The total pressure is the sum of the partial pressures and depends on the total moles of gas particles present, no matter what their identities. 

The partial pressures of CH4 and H2O, like the overall fluid pressure (Pf), depend on the fugacity of hydrogen arriving from deep sources under a certain pressure. The quantitative relationships between these gases are determined by the reactions ... 

Instead of c, the partial pressure of species 1 (or the total pressure if only one species is present) is generally measured in experiments and is used in equation (94). Since the proportionality factor between partial pressures and depends only on T, this factor may be absorbed into k, and equations (92) and (94) remain valid when concentrations are replaced by partial pressures. When written in terms of partial pressures, equation (94) is the Langmuir adsorption isotherm. 

These expressions are in agreement with experimental results namely, that the intensities of both singlet and triplet emissions are proportional to [SO] and [O3] and inversely proportional to total pressure. Further, the ratio /1//3 was independent of any variations of any of the partial pressures and depended only on the temperature. 

The kinetics of the new commercial process of hydroformylation of allyl alcohol was studied by Chaudhari in the temperature range from 60 to 80 °C [114]. The rate of reaction is first order in catalyst concentration and 1.5th order in hydrogen partial pressure. The dependence on p CO) does not differ from that observed in the hydroformylation of nonfunctionalized olefins. The reaction is retarded at higher substrate concentrations (> 1.25 mol/L). This substrate inhibition is not fully understood on the molecular level. The apparent activation energy for the oxo reaction of allyl alcohol was found to be 94 kJ/mol. 

The borderlines between low and high partial pressures may depend on the... 

Figure 9.13 Examples of the oxygen partial pressure (P02) dependencies of total conductivity of various solid electrolytes and mixed conductors, including apatite-type La9 g3Si4 5Ali xfSj(O26-s [204, 205],...

In a mixture of perfect gases, since the molecules take up no space and do not interact, each gas behaves as if it were alone in the container. The total pressure is therefore just the sum of the pressures that each of the gases would exert if it were alone in the same volume. These pressures are called the partial pressures of the gases. If nA molecules of perfect gas A and nB molecules of perfect gas B are mixed we may write the total pressure P as P = PA + JPB. The contributions of A and B to the total pressure will depend simply on the number of moles of each of these substances present. Thus the partial pressures PA and PB are given by... 

Figure 2 shows the dependence of the rate of carbon deposition with initial hydrogen partial pressure. The rate depends on the hydrogen partial pressure with a negative order, i.e., the rate of deposition decreases with increased hydrogen pressure. The dependence of the rate on the initial benzene partial pressure is first order as revealed by the data on Figure 1. For fixed temperatures, benzene and hydrogen partial pressures, there is a critical gas phase residence time (t ) below which no appreciable deposition occurs. Above the critical residence time t, deposition occurs and its rate increases linearly with gas residence time. This is depicted in Figure 3.

The dependence of DCB HDCl rates over Ni/Si02 on H2 and DCB pressure can be described in terms of the involvement of two types of active sites with a logarithmic dependence on H2 partial pressure. A rate maximum is observed with respect to DCB partial pressure where, under conditions of ascending rate, the reaction order with respect to DCB exceeds unity. The mechanism, which explains such kinetic regularities, assumes adsorption of two DCB molecules on adjacent sites and reaction with spillover hydrogen. Selectivity towards CIB was seen to be independent of H2 pressure but dependent on the nature of the isomer 1,2-DCB undergoes complete dechlorination to a greater extent and HDCl selectivity trends for 1,3-DCB and 1,4-DCB coincide. 

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