Slightly dense gas

In the context of this section, a slightly dense gas is a gas properly described by the first-order expansion in density, such as the linear term 

Since C is constant, it may be neglected, as compared with V, in the thermodynamic limit. Also, assuming that g(oo) is practically unity, we get the final form of g(R) for this case  

The foregoing derivation of (2.66) illustrates the origin of the coefficient R(R, R )j which, in principle, results from the simultaneous interaction of three particles [compare this result with (2.59)]. This is actually the meaning of the term slightly dense gas. Whereas in a very dilute gas we take account of interactions between pairs only, here we also consider the effect of interactions among three particles, but not more. 

Next we examine the content of the function R(R, R ) and its effect on g R) for a system of hard spheres (HS). In this case, one has the property 

Therefore, the only contribution to the integral in (2.52) comes from regions 

In the context of this section, a slightly dense gas is a gas properly described by the first-order expansion in the density, i.e., up to the linear term in (2.49). Before analyzing the content of the coefficient B(R R ) in the expansion of g(R), let us demonstrate its origin by considering a system of exactly three particles. Putting AT=3 in (2.48), we get 

Assuming pairwise additivity of the potential energy U3, and using the definition of the function /in (2.50), we can transform (2.59) into 

Note again that this is strictly true for an open system. See Appendix G. 

Note also that since f R) is a short-range function of R, the integral in (5.3.15) does not depend on V. 

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H2 was first recognized as a substance in 1766 by Henry Cavendish. It is the least dense gas, colorless, odorless, and tasteless. It is flammable and is slightly soluble in water. H2 is a mixture of the para and ortho forms, which differ in their electronic and nuclear spins. At room temperature, atmospheric hydrogen gas (GH2) is a mixture of 75% para-hydrogen and 25% ortho-hydrogen. Some of the properties of H2 are given in Table 1.43. 

Gas, however, feels a slightly reduced central force due to the outward pressure gradient that arises within the disk (hot, dense gas near the star and cool, sparse gas further out). The gas velocity, Vg, thus obeys ... 

This approach is based on the bulk flux Richardson number RJ, which is defined as the ratio of energy recovery due to entrainment and the energy production. It serves as an efficiency factor empirically known to be RJ 0.045 for subcritical flows and Kf 0.18 for supercritical ones (Bo Pedersen, 1980). Dense gas dispersion usually falls in the latter category. A solution is possible only with a slightly modified velocity scale e = and... 

It is a non-flammable eolourless gas whieh is twiee as dense as air, and slightly soluble in water forming sulphurous aeid. It is readily liquefied as a gas under its own vapour pressure of about 35 psig (2.4 bar) at 21°C. Figure 9.11 depiets the effeet of temperature on vapour pressure Table 9.26 lists the physieal properties. Cylinders tend to be proteeted against over-pressurization by metal plugs melting at about 85°C. 

This relative invariance of signal may be a consequence of a compensation effect. That is, as temperature increases, the test gas becomes slightly less dense on a moles CO/cm3 basis, but the diffusion coefficient increases slightly. 

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