Poising capacity

D. W. King, A General Approach for Calculating Spedation and Poising Capacity of Redox Systems with Multiple Oxidation States Application to Redox Titrations and the Generation of pe-pH Diagrams, J. Chem. Ed. 2002, 79, 1135. 

The digesting sludge therefore has a poising capacity which is not matched in the dialysate. When sludge is dialyzed against distilled water, the alkalinity, pH, volatile acids, etc. in the dialysate equalize in about a 10 day period. During that interval, the distilled water initially tends to have... 

From these results it can be concluded that the mechanism which induces the proper Ec level representing anaerobic fermentation is non-dialysable. It is not associated with solids which can be retained on Whatman filter paper, it is heat labile, and has a strong poising capacity about 100 mv below the level in equilibrated dialysate. 

The slope of the tangent to the curve at the inflection point where oc = is thus inversely proportional to the number of electrons n. The E-oc curves are similar to the titration curves of weak acids or bases (pH-or). For neutralization curves, the slope dpH/doc characterizes the buffering capacity of the solution for redox potential curves, the differential dE/da characterizes the redox capacity of the system. If oc — for a buffer, then changes in pH produced by changes in a are the smallest possible. If a = in a redox system, then the potential changes produced by changes in oc are also minimal (the system is well poised ). 

Since 1989, Cargill, has invested some 750 million to develop and commercialize polylactic acid (tradename NatureWorks). Its Nebraska plant, with an annual capacity of 140,000 metric tons, opened in 2002. Thus, polylactides, combining favorable economics with green sustainability, are poised to compete in large-volume markets that are now the domain of thermoplastic polymers derived from petrochemical sources. 

PRINT Enter Separation Ratio of the Critical Pair INPUT A PRINT Enter Capacity Ratio of the First Peak of the Pair" INPUT k I PRINT Enter Capacity Ratio of the Last Eluted Peak" INPUT K2 PRINT Enter Diffusivity of Solute in Mobile Phase UNPUT D1 PRINT Enter Viscosity of Mobile Phase (Poises)".INPUT M PRINT" Enter Column Inlet Pressure (p.s i)" INPUT P PRINT BASIC CHROMATOGRAPH IC DATA"... 

Separation Ratio (a, range 1 01 - i 12) (Critical Pair) i. 05 Capacity Ratio (first eluted peak of the Critical Pair) 2.5 Viscosity of the mobile phase (tj) 0.023 Poises... 

Stable Eh measurements are only possible in well-poised systems. Such systems, which are also described as having high redox capacity, tend to resist changes in Eh, just as systems with high... 

Strictly speaking, p is the oxidation capacity. The reduction capacity similarly defined is equal but opposite in sign to p). The units of p are, therefore, eq/L volt. In well-poised systems when oxidized and reduced species are electroactive at the electrode surface and both exceed roughly 10 to 10 M, Eh measurements are relatively easy and reproducible. Concentrations as low as 10 M can provide stable Eh readings in pure Fe(II)/Fe(OH)3(s) and Fe(lI)/Fe(IIl) systems (Macalady et al. 1990). On the other hand, in dilute and/or poorly poised waters. Eh measurements may drift without stabilizing for hours. 

Redox potential (Eh) characterises the oxidation-reduction condition of a soil. This in turn provides a means to assess soil genesis, soil fertility and status of soil contaminants (Liu Yu 1984). Redox potential is well known to be difficult to measure precisely with conventional methods, for reasons ranging from slow electrode response to soil condition, especially for poorly poised (redox capacity) soils (Bohn 1971 Ponnamperuma 1972). Usually measurements are made under specified conditions, with values being dependent on the experimental conditions. As the measured value is conditional, it may not be sufficiently precise for some physicochemical studies. Nevertheless, there is unique information about soil condition that can be derived by measuring the redox potential. 

The capacity factor in redox is referred to as poise and is defined as the change in added equivalents of reductant or oxidant to bring about a one unit change in pe (or Eh change of 59 mv). The concept is similar to that of buffer capacity for pH (Stumm Morgan 1996). However, poise in soils has been less studied than pH buffering. 

The system is poised to maintain very high levels of ATP at all times. In most tissues, the rate of ATP utilization is nearly constant over time. However, in skeletal muscles, the rates of ATP hydrolysis change dramatically as the muscle goes from rest to rapid contraction. Even under these circumstances, ATP concentration decreases by only approximately 20% because it is so rapidly regenerated. In the heart, Ca activation of TCA cycle enzymes provides an extra push to NADH generation, so that neither ATP nor NADH levels fall as ATP demand is increased. The electron transport chain has a very high capacity and can respond very rapidly to any increase in ATP utilization. 

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