Retention potential

Geochemical simulations (not shown) of water quality suggest that Ni is soluble in the test conditions, eliminating secondary mineral precipitation as an explanation for the absence of Ni in leachates. These observations could be explained by the metal retention potential of the Lac Tio waste rock being still active in the humidity cell tests. Consequently, the Ni produced in the humidity cell tests will continue to be retained by the fresh waste rock until saturation of the retention sites. 

Dried flavoring wall material development conducted in this study was completed in two separate phases. Firstly, a water-dispersable starch polymer which 1) exhibited good flavor retention potential during spray drying and 2) was able to form a stable flavor-incorporated aqueous emulsion was examined. 

Flood, J. F., Smith, G. E., 8c Gherkin, A (1983). Memory retention— Potentiation of cholinergic drug-combinations in mice. Neurobiology of Aging, 4, 37-43. 

Cap additives have to meet a number of prerequisites such as good retention potential, chemical and physical properties suited for an underwater application, low... 

Keywords Ab initio molecular dynamics simulations Always stable predictor-corrector algorithm Associated liquids Basis set Bom-Oppenheimer molecular dynamics simulations Car-Parrinello molecular dynamics simulations Catalysis Collective variable Discrete variable representation Dispersion Effective core potential Enhanced sampling Fictitious mass First-principles molecular dynamics simulations Free energy surface Hartree-Fock exchange Ionic liquids Linear scaling Metadynamics Nudged elastic band Numerically tabulated atom-centered orbitals Plane waves Pseudopotential Rare event Relativistic electronic structure Retention potential Self consistent field SHAKE algorithm ... 

G( X — y ) is a retention potential that ensures that the propagated wavefunction x stays close to the optimized wavefunction y and fi is a mass parameter, k = co is the force constant of the retention potential. 

PEC particle size can be influenced by various parameters related to preparation, PEL structure, and the medium (pH and concentration of PEL and salt). Preparative parameters have already been mentioned in Sect. 2.2. In this section, PEL structural parameters (Sect. 3.1) and then media parameters (Sect. 3.2) influencing PEC particle size will be discussed. Finally, sizing the internal structural density of PEC systems by structural and media parameters will be outlined (Sect. 3.3). In that frame, the pore size and the degree of compartmentation are important observables. This is of high relevance for PEC-based pharmaceutical carrier systems because pore size and compartmentation control the retention potential of PEC systems towards low and high molecular weight dmgs. 

Practical experience collected in recent years has shown, that wire abrasion is greatly influenced also by the conditions on the paper machine. In general, lower filler retention potentially increases wire wear. The wire drag load should be minimized, for example, by a low number of stationary drainage elements and optimized low vacuum loads. The dry suction box ceramic surfaces should display a low surface porosity and should be well maintained [3]. 

Retention, too, is highly tissue-specific. Sometimes, the extraction mechanism is also the retention mechanism, as for Tc-sestamibi, which is retained in mitochondria as long as transmembrane potentials remain intact. Others are separate. F-2-Fluorodeoxyglucose enters the cell by the same pathway as glucose, but is trapped because it is not a substrate for hexokinase, preventing further intracellular metabohsm. 

Transport processes describe movement of the pesticide from one location to another or from one phase to another. Transport processes include both downward leaching, surface mnoff, volatilization from the soil to the atmosphere, as weU as upward movement by capillary water to the soil surface. Transport processes do not affect the total amount of pesticide in the environment however, they can move the pesticide to sites that have different potentials for degradation. Transport processes also redistribute the pesticide in the environment, possibly contaminating sites away from the site of apphcation such as surface and groundwater and the atmosphere. Transport of pesticides is a function of both retention and transport processes. 

It is important to appreciate that the magnitude of the absorbed dose, the relative amounts of bio transformation product, and the distribution and elimination of metaboUtes and parent compound seen with a single exposure, may be modified by repeated exposures. For example, repeated exposure may enhance mechanisms responsible for biotransformation of the absorbed material, and thus modify the relative proportions of the metaboUtes and parent molecule, and thus the retention pattern of these materials. Clearly, this could influence the likelihood for target organ toxicity. Additionally, and particularly when there is a slow excretion rate, repeated exposures may increase the possibiUty for progressive loading of tissues and body fluids, and hence the potential for cumulative toxicity. 

Electroultrafiltration (EUF) combines forced-flow electrophoresis (see Electroseparations,electrophoresis) with ultrafiltration to control or eliminate the gel-polarization layer (45—47). Suspended colloidal particles have electrophoretic mobilities measured by a zeta potential (see Colloids Elotation). Most naturally occurring suspensoids (eg, clay, PVC latex, and biological systems), emulsions, and protein solutes are negatively charged. Placing an electric field across an ultrafiltration membrane faciUtates transport of retained species away from the membrane surface. Thus, the retention of partially rejected solutes can be dramatically improved (see Electrodialysis). 

Other advantages of gravity beds include flexibility in gas and sohds flow rates and capacities, variable retention times from minutes to several hours, space economy, ease of startup and shutdown, the potentially large number of contacting stages, and ease of control by using the inlet- and exit-gas temperatures. 

It is seen that the curves in Figure (24) become horizontal between 40°C and 45 °C as predicted by the theory. It is also clear that there is likely source of error when exploring the effect of solvent composition on retention and selectivity. It would be important when evaluating the effect of solvent composition on selectivity to do so over a range of temperatures. This would ensure that the true effect of solvent composition on selectivity was accurately disclosed. If the evaluation were carried out at or close to the temperature where the separation ratio remains constant and independent of solvent composition, the potential advantages that could be gained from an optimized solvent mixture would never be realized. 

Water-retention curve Graph showing soil-water content as a function of increasingly negative soil water potential. 

Mobile phases with some solvating potential, such as CO2 or ammonia, are necessary in SGC. Even though this technique is performed with ambient outlet pressure, solutes can be separated at lower temperatures than in GC because the average pressure on the column is high enough that solvation occurs. Obviously, solute retention is not constant in the column, and the local values of retention factors increase for all solutes as they near the column outlet. 

In the introduction to this chapter, MD-PC was defined as a procedure in which substances to be separated were subjected to at least two separation steps with different mechanisms of retention (5). Discussion of the basic potential modes of operation showed that because of the versatility which resulted from being able to combine mobile phases of different composition, more than two development steps can easily be realized by the use of "D techniques. 

One potential problem associated with column coupling in reversed phase is relatively high back-pressure ( 2600 psi at 1 mL miir ). This will place a limit on the flow rate, which in turn limits the further reduction of analysis time. Also, compared to the new polar organic mode, the retention in reversed phase on coupled columns is deviated more from the average retention on the individual stationary phases. 

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