Accommodation coefficient table

Tables 2,3, and 4 outline many of the physical and thermodynamic properties ofpara- and normal hydrogen in the sohd, hquid, and gaseous states, respectively. Extensive tabulations of all the thermodynamic and transport properties hsted in these tables from the triple point to 3000 K and at 0.01—100 MPa (1—14,500 psi) are available (5,39). Additional properties, including accommodation coefficients, thermal diffusivity, virial coefficients, index of refraction, Joule-Thorns on coefficients, Prandti numbers, vapor pressures, infrared absorption, and heat transfer and thermal transpiration parameters are also available (5,40). Thermodynamic properties for hydrogen at 300—20,000 K and 10 Pa to 10.4 MPa (lO " -103 atm) (41) and transport properties at 1,000—30,000 K and 0.1—3.0 MPa (1—30 atm) (42) have been compiled. Enthalpy—entropy tabulations for hydrogen over the range 3—100,000 K and 0.001—101.3 MPa (0.01—1000 atm) have been made (43). Many physical properties for the other isotopes of hydrogen (deuterium and tritium) have also been compiled (44).

The pressure dependence of effective viscosity obviously depends upon the value of the momentum accommodation coefficient. Momentum accommodation data are relatively rare, but some representative data are given in Table 1. Note that all values are relatively close to unity. Because of this observation, momentum accommodation coefficients are normally assumed to be unity in applications... 

Table 4 Experimental Data for Energy Accommodation Coefficient...

Heterogeneous uptake on surfaces has also been documented for various free radicals (DeMore et al., 1994). Table 3 shows values of the gas/surface reaction probabilities (y) of the species assumed to undergo loss to aerosol surface in the model. Only the species where a reaction probability has been measured at a reasonable boundary layer temperature (i.e. >273 K) and on a suitable surface for the marine boundary layer (NaCl(s) or liquid water) have been included. Unless stated otherwise, values for uptake onto NaCl(s), the most likely aerosol surface in the MBL (Gras and Ayers, 1983), have been used. Where reaction probabilities are unavailable mass accommodation coefficients (a) have been used instead. The experimental values of the reaction probability are expected to be smaller than or equal to the mass accommodation coefficients because a is just the probability that a molecule is taken up on the particle surface, while y takes into account the uptake, the gas phase diffusion and the reaction with other species in the particle (Ravishankara, 1997). 

The accommodation coefficients for OH and HO2 in our model are parameterised as temperature dependent accommodation coefficients (Gratpanche et al., 1996) in Table 3, with no account taken of the surface characteristics. There are a few papers reporting uptake coefficients for both OH and HO2 with lower limits quoted for the HO2 coefficients due to experimental limitations, giving rise to a low confidence in current experimental values for HO2 (Cooper and Abbatt, 1996 Hanson et al., 1992). The impact of reactions on aerosol on HO2 concentrations in the remote atmosphere could be significant if the uptake coefficient was greater than 0.1, and could dominate if it was close to unity (Saylor, 1997). 

Table 8.5 shows the mass accommodation coefficients for S02, as well as for some other gases of tropospheric interest, on liquid water. It is seen that the uptake of most gases into liquid water is quite efficient. Interactions of gas molecules at the air-liquid interface may have additional implications other than the rate at which it is transferred into the aqueous... 

TABLE 8.5 Some Mass Accommodation Coefficients (a) for Gases of Tropospheric Interest on a Liquid Water Surface"... 

The values of the energy accommodation coefficient for the recombination of H and O atoms by metals measured by Wood et al. [89] and by Melin and Madix [77] are given in Table 6. The /3(H) values of Wood et al. for nickel, platinum and tungsten are substantially higher than those reported by Melin and Madix, but no explanation appears to be forthcoming for this difference. From Table 6, it is seen that a given metal has... 

The values of the accommodation coefficient ]3 for the recombination over silver and gold (see Table 6) are probably high enough to be compatible with reaction between mobile adatoms, but the low value for copper is not. Once again, we face the same dilemma posed by recombination over the Group IB metals. 

Table 1 compares the dimensionless coagulation coefficient predicted by the present model with other models. Since the Hamaker constant for most of the aerosol systems is of the order of 10"12 eig, this value is used in the calculation of the lower bound. Particle diffusion coefficients based on Philips slip correction factor for an accommodation coefficient of unity are used for the calculation of the coagulation coefficients ft (the Fuchs interpolation formula) and fts (the Sitarski... 

It was assumed that the motion of the fictitious particle within the above time steps is rectilinear. This simplification, which accelerates the computer calculation of the trajectories of the fictitious particle, has been show n to be justified (9). The Philips slip correction factor for an accommodation coefficient of unity (Eq. [4]) was used in the calculation of the diffusion coefficients of particles. The values of the dimensionless coagulation coefficients % obtained by the computer simulation for different particle sizes, are given in Table I. The statistical errors of the Monte Carlo simulation were estimated by the standard 3 a method (corresponding to a probability of 0.997) (13). The number of particle pairs that must be generated in order to lower the error to a reasonable level depends both on the initial distance of separation between... 

Values of the accommodation coefficient must be determined from experiment, and a brief summary of such measurements is given in Table 12-1. 

The table shows that all the calculations and the data are in good agreement, with the worst case being a factor of five. The uncertainty in the absolute magnitude of the spectral radiance data is 25%. The uncertainty in the wavelength calibration of the instrument of about 10 A is sufficient to explain the discrepancy in the peak wavelength positions for the DSMC calculations with an accommodation coefficient less than one. An accommodation coefficient of 0.85 seems to provide the best overall agreement. 

The values of y were similarly obtained for dimer CBA- (n = 9,10) and trimer CBA-Tn (n = 9,10). These compounds exhibit the nematic LC phase over a limited temperature range, hampering an accurate estimation of y by the extrapolation from this phase. Accordingly the y values were estimated by method 1 only from higher-temperature phases i.e., y i values are estimated from the isotropic phase, and ycN values from the nematic phase [95]. The ytr values thus derived are all accommodated in Tables 2 and 3, respectively, for the NI and CN transitions. Thermal pressure coefficients of monomer liquid crystals such as 4-cyano-4 -alkylbiphenyls ( CB) and 4-cyano-4 -alkoxybiphenyls ( OCB) are available in the article by OrwoU et al. [112]. The y values applicable to the NI transition of these compounds are cited in Table 4 for comparison. As shown in these tables, use of the volume change A Vtr at the transition (column 4) leads to the estimate of the volume-dependent entropy ASy (column 5) according to Eq. 3. 

Gas Flow in Nanochannels, Table 2 Poiseuille coefficient vems accommodation coefficients at and On [14]... 

Micro- and Nanoscale Gas Dynamics, Table 2 Poiseuille coefficient Gp versus accommodation coefficients a, and (Reprinted with permission from [5]) ... 

Gp for the CL scattering kernel obtained in [5] are given in Table 2. In all regimes the influence of the energy accommodation coefficient on the flow rate is weak, while the momentum accommodation coefficient ott affects significantly the flow rate in the transition (8 = 1) and near the free molecular (5 = 0.01) regimes. 

Table 10.1. Values of Accommodation Coefficients and Other Constants According to Equations (10.3) and (10.10) for PeZn and FigPcZn Electrodes in Different Electrolytes as Indicated in Parentheses. The Indices cath and an Stand for the Observed Cathodic or Anodic Photocurrents, Respectively...

Based on the input coefficients table of producers prices, 52 sub-industrial sectors are combined into 9 main sectors including Agricultural, Forestry, Fishery and Animal Husbandry (A), Manufacturing (B), Electricity, Gas and Water (C), Construction (D), Trade, Accommodation, and Food and Beverage (E), Transportation and Communication (F), Banking, Insurance Entities and Real Estate (G), Industry, Commerce and Services (H), and Social and Personal Services (I). The EIO technical coefficients for these nine sectors are shown in Table 26.2. 

If we use the accommodation coefficient of SO2 molecule to the water particle surface given in Table 6.1, a >0.12, Uav = 4.7 x 10 cm s and liquid water content, L = 5 x 10 (l(aq)/l(air)), and particle radius, r = 7 x 10 " cm. Pi is calculated to be 3.0 s , and the characteristic time necessary for the uptake from the gas phase to the liquid surface is the order of 0.1 s by taking the reciprocal. Furthermore, SO2 molecules taken into water droplets react with H2O molecules at the liquid surface, and reach to chemical equiUhrium with three sulfur species, S02 H20, HSO3 and 803 as mentimied later. The time for reaching to the chemical equiUhrium is as short as 10 s. 

TABLE 5.3. Thermal Accommodation Coefficients y(oo) for High Energies of the Gas... 

The accommodation coefficients and uj- depend on the gas and surface temperatures and local pressure. Table 3.1 shows the typical accommodation coefficient for some gas-surface combinations. Accommodation coefficient also depends on the Knudsen number of the flow. Figure 3.3 shows the variation of accommodation coefficient with respect to the Knudsen number for nitrogen gas. 

Table 3.1 The accommodation coefficient for different gas-surface combinations...

Some typical accommodation coefficient values for common gases at several different temperatures are presented in Table 7.3. 

Table 7.3. Accommodation Coefficients for Several Gases at Three Temperatures...

Since the mean free path of the molecules is much larger than the space between the inner and outer vessels, free molecular conduction, occurs. The accommodation coefficients from Table 7.3 for air at 300 and 90 K are 0.85 and 1.0, respectively. The accommodation coefficient factor is obtained with the aid of Eq. (7.10) ... 

Yamase and Goto406 determined first- and second-order rate coefficients for the aluminium chloride-catalysed reaction of halide derivatives of benzoic acid (lO5 = F, 1.73 Cl, 4.49 Br, 4.35 I, 0.81) and phenylacetic acid (105fc2 = F, 12 Cl, 21 Br, 9 I, 6) with benzene. The maxima in the rates for the acid chloride are best accommodated by the assumption that a highly (but not completely) polarised complex takes part in the transition state. Polarisation of such a complex would be aided by electron supply, and consistently, the acetyl halides are about a hundred times as reactive as the benzoyl compounds (see p. 180, also Tables 105 and 108). 

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