Dominant effects

It is, of course, widely considered that the classical TST provides the central framework for the understanding of thennal rate constants (see the review article by Tnihlar et al [13]) and also for quantifying the dominant effects of the considered phase in chemical reactions (see below). 

The off-diagonal elements represent the dominant effects of bonding and are set to be proportional to the overlap by a parameter dependent on the two atoms involved in the overlap. 

Equation 14 indicates that Hquid pressure has a dominant effect in controlling the mean droplet sizes for pressure atomizers. The higher the Hquid pressure, the finer the droplets are. An increase in Hquid viscosity generally results in a coarser spray. The effect of Hquid surface tension usually diminishes with an increase in Hquid pressure. At a given Hquid pressure, the mean droplet size typically increases with an increase in flow capacity. High capacity atomizers require larger orifices and therefore produce larger droplets. 

Oxolamine [959-14-8] (57) is sold in Europe. It is an oxadiazole, and its general pharmacological profile is described (81). The compound possesses analgesic, antiinflammatory, local anesthetic, and antispasmodic properties, in addition to its antitussive activity. Although a central mechanism may account for some of the activity, peripheral inhibition of the cough reflex may be the dominant effect. The compound has been shown to be clinically effective, although it is less active than codeine (82,83). The synthesis of oxolamine is described (84). 

This is opposite from the order in solution as revealed by the pK data in water and DMSO shown in Table 4.14. These changes in relative acidity can again be traced to solvation effects. In the gas phase, any substituent effect can be analyzed directly in terms of its stabilizing or destabilizing effect on the anion. Replacement of hydrogen by alkyl substituents normally increases electron density at the site of substitution, but this effect cannot be the dominant one, because it would lead to an ordering of gas-phase acidity opposite to that observed. The dominant effect is believed to be polarizability. The methyl... 

Boron is a unique and exciting element. Over the years it has proved a constant challenge and stimulus not only to preparative chemists and theoreticians, but also to industrial chemists and technologists. It is the only non-metal in Group 13 of the periodic table and shows many similarities to its neighbour, carbon, and its diagonal relative, silicon. Thus, like C and Si, it shows a marked propensity to form covalent, molecular compounds, but it differs sharply from them in having one less valence electron than the number of valence orbitals, a situation sometimes referred to as electron deficiency . This has a dominant effect on its chemistry. 

The impact of Ice Storm 98 can clearly be seen by realizing that the number of customer interruptions and the customer hours of interruption for all of Canada in 1997 were 24,280,244 and 38,130,783, respectively. The ice storm alone resulted in 12,332,950 customer interruptions and 282,576,829 customer hours of interruption in the utilities affected. Removing the ice storm incidents from the 1998 Canada-wide data results in a SAIFI of 2.46 and a SAIDI of 3.40. The lOR is 99.9612 percent. Ice Storm 98 had only a relatively moderate effect on SAIFI but a dominant effect on the customer hours of interruption and the SAIDI statistic due to the extremely long storm duration and the required restoration period. It is important to realize that the bulk transmission system retained its integrity according to NERC criteria, and the impact of the ice storm on Ontario Hydro facilities did not propagate into neighboring interconnected utilities. 

Broutman and McGarry [98] examined the effects of crosslinking on toughness as early as 1965. Bell [99] observed a threefold increase in notched impact strength as the molecular mass between crosslinks was increased. Schmid et al. [100] and Lohse et al. [101] pointed out the dominating effect of molecular strand length on the ultimate properties and the toughness of crosslinked polymers. Later, Batzer et al. [46], Schmid [44], and Fischer et al. [45] compared the behavior of various networks composed of epoxy resins. 

Chemical interactions also occur in the condensed phases. Some of these are expected to be quite complex, e.g., the reactions of free radicals on the surfaces of or within aerosol particles. Simpler sorts of interactions also exist. Perhaps the best understood is the acid-base relationship of NH3 with strong acids in aerosol particles and in liquid water (see Chapter 16). Often, the main strong acid in the atmosphere is H2SO4, and one may consider the nature of the system consisting of H2O (liquid), NH3, H2SO4, and CO2 under realistic atmospheric conditions. Carbon dioxide is not usually important to the acidity of atmospheric liquid water (Charlson and Rodhe, 1982) the dominant effects are due to NH3 and H2SO4. The sensitivity the pH of cloud (or rainwater produced from it) to NH3 and... 

The polishing pad, as another consumable material, also has a dominating effect in the CMP process, which is usually made of a matrix of cast polyurethane foam with filler material to control hardness of polyurethane impregnated felts. The pad carries the slurry on top of it, executes the polishing action, and transmits the normal and shear forces for polishing, thereby playing a very cnacial role in process optimization [44 6]. 

One notes in Table 1.2 a uniform increase in the adsorption energies of the alkanes when the microspore size decreases (compare 12-ring-channel zeohte MOR with 10-ring-channel TON). However, at the temperature of hydroisomerization the equilibrium constant for adsorption is less in the narrow-pore zeohte than in the wide-pore system. This difference is due to the more limited mobility of the hydrocarbon in the narrow-pore material. This can be used to compute Eq. (1.22b) with the result that the overall hydroisomerization rate in the narrow-pore material is lower than that in the wide-pore material. This entropy-difference-dominated effect is reflected in a substantially decreased hydrocarbon concentration in the narrow-pore material. 

Phosphorus and arsenic have nearly identical electronegativities, so in GaP Asi. , the dominant effect is the smaller atomic radius of P relative to As. Substituting P atoms for As atoms shrinks the dimensions of the semiconductor lattice. This leads to greater overlap of the valence orbitals, increased stability of the bonding orbitals (valence band), and an increased band gap. 

In a Poiseuille flow of a Newtonian liquid the coherent motion gives rise to the dominant effect, rendering contributions from the stochastic dispersion term... 

The data of Table II indicate that the etch rates for CB and its "homologues"—TP, CO (or TO), and EPM—tend to increase monotonically with a decrease in vinylene (-CH=CH-) unsaturation. The elastomeric EPM was chosen instead of crystalline polyethylene as a model for the fully saturated CB to avoid a morphology factor in etch rates, as was observed with crystalline TB. The difference in etch rates for the partially crystalline TO and the elastomeric CO (ratio of about 1.2 1.0) is attributable more to a morphology difference between these polyoctenamers than to the difference in their cis/trans content. Cis/trans content had likewise no perceptible effect on etch rates in the vinyl-containing polybutadienes (see Table I) if there was a small effect, it was certainly masked by the dominant effect of the vinyl groups. 

---