Vance 1 well

The higher reaction rate per unit Ni area in the case of a supported catalyst in comparison with the case of pure nickel may be due to the way in which the catalyst material interacts with the support material to form a crystal structure with a certain nature, which in turn affects the activity/selectivity properties. This was reported by Vance and Bartholomew (1983). It was shown that the Ni-support interactions significantly influence the adsorption of reactants and reaction intermediates on nickel as well as the activity/selectivity properties of nickel CO2 hydrogenation. 

Anderson et al. [34] have measured cross sections for CID of state-selected D2+ (v) + HD. Unfortunately, no data exists for H2+ (v) + H2 to compare with our work. We can, however, compare our results with those of Vance and Bailey [32], who obtained cross sections for an unselected beam of H2. If we assume their distribuiion of vibrational levels was Franck-Condon, we estimate an averaged cross section of 9.4 A2 at 8 eV. This compares favorably with their value of 10.9 A2 as well as with the value of 10.3 A2 measured by Lee et al. [36]. The increase of the CID cross sections with vibrational levels is not surprising, because the dissociation energy decreases rapidly with v. Nevertheless, it is impressive that CID cross sections as large as 7 A2 are obtained in this system. Simple theoretical treatments of CID, such as the optical model of Levine and Bernstein [38], predict that the cross sections should increase rapidly with translational energy. This is clearly not the case for H2+ + H2. 

Vance and Bailey [94] also carried out measurements of velocity distributions of product ions using a double mass-spectrometer system similar to the one used by Giese and Maier [95] combined with the retardation product-ion analysis by Menendez et al. [96]. They studied the charge transfer and dissociative charge transfer reactions of Hj and N2 with H2, as well as the reaction + H2 H3 + H, and the results yielded considerable new information on the reaction mechanism. 

Oxidation-reduction reactions play a very important role in geochemical processes, particularly in the remediation processes of subsurface contamination. The reactions determine the mobility of many inorganic contaminants, as well as of many biologically important elements such as nitrogen and sulfur in the subsurface, and the toxicity of some metallic contaminants (Vance, 1996). For example, chromium can exist in the subsurface in valence states ranging from -2 to +6, with the trivalent Cr(III) and hexavalent Cr(VI) states being the most stable in the surface and subsurface environments. Cr(III) can exist in the form of cation Cr + or hydroxo complexes such as CrOH, Cr(OH)3, and Cr(OH)4. The cationic Cr(III) species... 

The solution of the above system of equations can be found, e.g., in Vertes and Kiss (1987), Ehmann and Vance (1991) as well as several authors of this handbook refer to the result summarized by O Eqs. (7.42)-(7.43) as the Bateman equation (Bateman 1910, see also in Choppin and Rydberg 1980). Other authors refer to the whole series of equations shown in O Eq. (7.40) as Bateman equations.) For the nth member of the series (n = 1, 2, 3,...) one gets... 

NCES, 1977. National Center for Education Statistics. Earned Degrees Conferred, 1974-75 Summary Data. By Curtis O. Baker and Agnes Q. Wells. NCES 77-328. NCES, 1978a. National Center for Education Statistics. Digest of Education Statistics, 19 77- 78. By W. Vance Grant and C. George Lind. 

The effects of organic acids in weathering environments are well documented and described in detail elsewhere (e.g., Stumm et al. 1985 Grand-staff 1986 Mast and Drever 1987 Amrhein and Suarez 1988 Bennett et al. 1988 Bennett 1991 Chin and Mills 1991 also Drever and Vance, Chap. 6, this Vol. Bennett and Casey, Chap. 7, this Vol.). In general, experimental work at the low temperatures indicates that organic acids may increase both the solubility and dissolution kinetics of silicates. 

Gimblett and Monk (1954) determined the stability constant of SrOH" from the earlier data of Harned and Paxton (1953) over a temperature range of 5-45 °C. They also estimated a value at 25 °C from the much earlier data of Vance (1933). It was found that this value agreed extremely well with the value determined from... 

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