Summary Observations

The rates of dissolution of carbonates and aluminosilicates as a function of pH are generalized in Fig. 2.11. Calcite and dolomite dissolution rates are generally 10 to 1 O -fold faster than rates for the silicates and decrease with pH up to saturation with the carbonates, usually between pH 8 and 10. Dissolution rates among the silicates range widely and are greatest for rapidly weathered minerals such as nepheline and olivine and slowest for quartz, muscovite (illite) and kaolinite, important products of chemical weathering in soils, discussed in more detail in Chap. 7. 

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I m going to conclude now with just a few summary observations. 

In summary, observations of increased rates of MW-assisted homogeneous reactions, compared with classically heated reactions at the same apparent temperature, may be explained by one or more of the following problems or effects ... 

Studies are reviewed in some detail by Moutschen-Dahmen et al. (ref. 2b, sec 3-2ff). They include the following summary observations of interest (a) eight of 17 OPPs induced sister chromatid exchange (SCE) in Chinese hamster V79 cells cultured in vivo (b) nine of 10 OPPs tested also induced SCE in Chinese hamster ovary (CHO) cells (c) oxygen was more effective than S in SCE induction, and (d) SCE induction appears to be a common property of OPPs. 

Summary observations and issues of importance to naval forces within each of the five commodity areas are offered in this section to help underpin the recommendations that have been discussed so far in this chapter. (Appendix C offers a more complete discussion of these areas.)... 

Based on the information made available to the committee, the following summary observations describe the committee s impressions 11... 

This volume and its companion. Inventing the Electronic Century The Epic Story of the Consumer Electronics and Computer Industries, focus on three revolutions that have transformed life and work on this planet during the past century and a half the Industrial, the Information, and the Biotechnology Revolutions. Inventing the Electronic Century deals with the second of these revolutions the present volume reviews the first and the beginning of the third. In this chapter, I compare and contrast the histories of all three revolutions and offer some summary observations and conclusions. 

In summary, observed effects of individual phenolic acids or phenolic acid mixtures were similar to what had been observed in nutrient culture but the response times and the magnitude of effects (see Section 2.4.8 for direct comparison) were slower and lower, respectively. Relative potencies of phenolic acids were lower when compared to nutrient culture. Increasing the number of phenolic acids in a mixture of phenolic acids reduced the concentrations of the individual phenolic acids required for a given percent inhibition. The presence of other readily available organic compounds (inhibitory or non-inhibitory) also reduced the concentration of phenolic acids required for a given percent inhibition. The addition of nitrate or nutrient solution reduced the inhibitory activity of phenolic acids. The inhibition of methionine, an amino acid, on the other hand was enhanced by the addition of nitrate. Finally phenolic acid effects were greater under acidic than under neutral conditions. 

In summary, observation of reduction in situ revealed that the hydroxylated ferric surface of the precursor is converted into a largely ferrous surface, free of water after a long induction period. Only a fraction of the surface iron is reduced to an ill-defined metallic state. Neither a film of chemisorbed water nor other molecular contaminants block the surface and prevent the reduction from proceeding. This is in contrast to the kinetic studies described in Section 2.5, which deal with the high-pressure reduction of iron oxides where, under identical conditions, ferrous ions are more easily reduced than ferric ions. 

Figure Bl.7.7. Summary of the other collision based experiments possible with magnetic sector instruments (a) collision-mduced dissociation ionization (CIDI) records the CID mass spectrum of the neutral fragments accompanying imimolecular dissociation (b) charge stripping (CS) of the incident ion beam can be observed (c) charge reversal (CR) requires the ESA polarity to be opposite that of the magnet (d) neutiiralization-reionization (NR) probes the stability of transient neutrals fonned when ions are neutralized by collisions in the first collision cell. Neutrals surviving to be collisionally reionized in the second cell are recorded as recovery ions in the NR mass spectrum.

In summary, solvents can influence Diels-Alder reactions through a multitude of different interactions, of which the contributions to fire overall rate uniquely depend on the particular solvent-diene-dienophile combination. Scientists usually feel uncomfortable about such a situation and try to extract generalities. When limited to the most extensively studied type A Diels-Alder reactions this approach seems feasible. These Diels-Alder reactions are dominated by hydrogen bonding interactions in combination with solvophobic interactions. This observation predicts a very special role of water as a solvent for type A Diels-Alder reactions, which is described in Section 1.4. 

In summary, the groups of Espenson and Loh observe catalysis of Diels-Alder reactions involving monodentate reactants by Lewis acids in water. If their observations reflect Lewis-acid catalysis, involvirg coordination and concomitant activation of the dienophile, we would conclude that Lewis-acid catalysis in water need not suffer from a limitation to chelating reactants. This conclusion contradicts our observations which have invariably stressed the importance of a chelating potential of the dienophile. Hence it was decided to investigate the effect of indium trichloride and methylrhenium trioxide under homogeneous conditions. 

In summary, the work in this thesis provides an overview of what can be achieved with Lewis-acid and micellar catalysis for Diels-Alder reactions in water as exemplified by the reaction of3-phenyl-l-(2-pyridyl)-2-propene-l-ones with cyclopentadiene. Extension of the observed beneficial effect of water on rates and particularly enantioselectivities to other systems is envisaged. 

Whenever a phase is characterized by at least one linear dimension which is small, the properties of the surface begin to make significant contributions to the observed behavior. We shall examine the structure of polymer crystals in more detail in Sec. 4.7, but for now the following summary of generalizations about these crystals will be helpful ... 

Holzworth, G. C., and Fisher, R. W., "Climatological Summaries of the Lower Few Kilometers of Rawinsonde Observations," EPA-600/4-79-026. U.S.Environmental Protection Agency, Research Triangle Park, NC, 1979. 

Summary of Lowest Observed Effect Levels for Key Lead-Induced Health Effects in Adults... 

Fig. 8. Summary of real and imaginary e2(tu) parts of the dielectric function for Cgo vacuum-sublimed solid films at room temperature over a wide frequency range, using a variety of experimental techniques. The arrow at the left axis points to i = 4.4, the observed low frequency value of ei obtained from optical data [81].

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