Shallowness factor

Table I. Shallowness Factors, Relative Retentions, and Maximum Absorbances for Selected Compounds...

Compound Number Shallowness Factor Relative Retention Maximum Absorbance (nm)... 

For turbulent flow through shallow tube banks, the average friction factor per row will be somewhat greater than indicated by Figs. 6-42 and 6-43, which are based on 10 or more rows depth. A 30 percent increase per row for 2 rows, 15 percent per row lor 3 rows and 7 percent per row for 4 rows can be taken as the maximum likely to be encountered (Boucher and Lapple, Chem. Eng. Prog., 44, 117—134 [1948]). 

In conclusion, one important factor that contributes to the strong affinity of TBP proteins to TATA boxes is the large hydrophobic interaction area between them. Major distortions of the B-DNA structure cause the DNA to present a wide and shallow minor groove surface that is sterically complementary to the underside of the saddle structure of the TBP protein. The complementarity of these surfaces, and in addition the six specific hydrogen bonds between four side chains from TBP and four hydrogen bond acceptors from bases in the minor groove, are the main factors responsible for causing TBP to bind to TATA boxes 100,000-fold more readily than to a random DNA sequence. 

While designing completion/workover fluids the main consideration is given to the effect of the fluids on well s productivity. Low production rates can be due to factors that are unrelated to the fluids introduced to the production zone. These would include poor or shallow perforations, cement filtrate invasion, paraffin wax deposition from crude oil, or movement of formation sand to block the well-bore. 

It is necessary that an accurate estimate of the total time be for the actual operation. A safety factor should be added to this estimate. Usually this safety factor is from 30 min (for shallow operations) to as long as 2 hr (for deep complex operations). 

Table II summarizes analytical data for dissolved inorganic matter in a number of natural water sources (J3, 9, J 9, 20, 21). Because of the interaction of rainwater with soil and surface minerals, waters in lakes, rivers and shallow wells (<50m) are quite different and vary considerably from one location to another. Nevertheless, the table gives a useful picture of how the composition of natural water changes in the sequence rain ->- surface water deep bedrock water in a granitic environment. Changes with depth may be considerable as illustrated by the Stripa mine studies (22) and other recent surveys (23). Typical changes are an increase in pH and decrease in total carbonate (coupled), a decrease in 02 and Eh (coupled), and an increase in dissolved inorganic constituents. The total salt concentration can vary by a factor of 10-100 with depth in the same borehole as a consequence of the presence of strata with relict sea water. Pockets with such water seem to be common in Scandinavian granite at >100 m depth.

Krishnaswami S, Graustein WC, Turekian KK, Dowd F (1982) Radium, thorium, and radioactive lead isotopes in groundwaters application to the in-situ determination of adsorption-desorption rate constants and retardation factors. Water Resour Res 6 1663-1675 Krishnaswami S, Bhushan R, Baskaran M (1991) Radium isotopes and Rn in shallow brines, Kharaghoda (India). Chem Geol (Isot Geosci) 87 125-136 Kronfeld J, Vogel JC, Talma AS (1994) A new explanation for extreme " U/ U disequilibria in a dolomitic aquifer. Earth Planet Sci Lett 123 81-93... 

Figure 5. Comparison between fluxes measured in shallow sediment traps and those calcnlated for the same depth and time from the " Th deficit in the overlying water colnmn. The data were compiled from many studies and the right-hand scale shows the factor of positive or negative offset between the two data sets. Significant differences are common and are linked to the varions assumptions and constraints of the two approaches for measnring POC finx. [Reprinted from Nature, Vol. 353, Buesseler, pp. 420-423, 1991, Macmillan Publishers Ltd.]...

Baskaran and Santschi (1993) examined " Th from six shallow Texas estuaries. They found dissolved residence times ranged from 0.08 to 4.9 days and the total residence time ranged from 0.9 and 7.8 days. They found the Th dissolved and total water column residence times were much shorter in the summer. This was attributed to the more energetic particle resuspension rates during the summer sampling. They also observed an inverse relation between distribution coefficients and particle concentrations, implying that kinetic factors control Th distribution. Baskaran et al. (1993) and Baskaran and Santschi (2002) showed that the residence time of colloidal and particulate " Th residence time in the coastal waters are considerably lower (1.4 days) than those in the surface waters in the shelf and open ocean (9.1 days) of the Western Arctic Ocean (Baskaran et al. 2003). Based on the mass concentrations of colloidal and particulate matter, it was concluded that only a small portion of the colloidal " Th actively participates in Arctic Th cycling (Baskaran et al. 2003). 

The relative reactivity profile of the simple alkenes toward Wacker oxidation is quite shallow and in the order ethene > propene > 1-butene > Zi-2-butene > Z-2-butene.102 This order indicates that steric factors outweigh electronic effects and is consistent with substantial nucleophilic character in the rate-determining step. (Compare with oxymercuration see Part A, Section 5.8.) The addition step is believed to occur by an internal ligand transfer through a four-center mechanism, leading to syn addition. 

The development of PACG is associated with several anatomic risk factors that lead to shallow anterior chambers. PACG patients may have a thick, anteriorly displaced lens that results from myopia or old age. The axial length of the eye is smaller in individuals with PACG, which leads to a lens that is situated more anteriorly than those without PACG.27,28... 

Containment of the flushed contaminants and spent flushing solutions is essential to successful application of in situ flushing. This happens when the treatment zone is bounded geologically by materials with relative low hydraulic conductivity. Depth to the contaminated zone is a limiting factor because of the higher injection and extraction costs that are required compared with more shallow contaminated zones. Contaminants can be easily removed when the flushing solution follows the same channels as the pollutant. Also, possible mechanical disturbance of the surface layer of the contaminated area may render the contaminants inaccessible. 

Table 20.4 presents the partition and transformation processes known to occur in the near-surface environment along with the special factors that should be considered when evaluating data in the context of the deep-well environment. Geochemical processes affecting hazardous wastes in deep-well environments have been studied much less than those occurring in near-surface environments (such as soils and shallow aquifers). Consequently, laboratory data and field studies for a particular substance may be available for near-surface conditions, but not for deep-well conditions. 

Factors that affect the costs for excavation include the depth of contamination, depth of ground-water (requiring dewatering), and extent of underground infrastructure and/or nearby structures that require shoring. The cost for excavation tends to be higher for areas with deeper contamination, shallower groundwater, and more infrastructures and nearby structures. 

Thus the hydrogen-bonding is apparently dependent, amongst other factors, upon the nature of the alkyl substituents. Perhaps the more highly branched secondary alkyl substituents increase the hydrophobic environment about the hydrogen bond, thereby favoring a symmetrical interaction. In any event, it is apparent that this interaction is best described by a very broad, shallow potential function. 

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