Physicochemical variables

An important application of foams arises in foam displacement, another means to aid enhanced oil recovery. The effectiveness of various foams in displacing oil from porous media has been studied by Shah and co-workers [237, 238]. The displacement efficiency depends on numerous physicochemical variables such as surfactant chain length and temperature with the surface properties of the foaming solution being an important determinant of performance. 

The relation between zinc content in carbonate and many physicochemical variables such as /02, temperature, pH, and so on was derived on the basis of the equilibrium between coexisting carbonate and sphalerite (Figs. 1.95 and 1.96). It is predicted theoretically that zinc content increa.ses with increasing /oj in the oxidized sulfur species and oxidized carbon species region (Fig. 1.95). This estimate is consistent with mineral assemblage containing the siderite. 

In a similar way, the Systeme Internationale has defined other common physicochemical variables. The SI unit of temperature T is the kelvin. We define the kelvin as 1/273.16th part of the thermodynamic temperature difference between absolute zero (see Section 1.4) and the triple point of water, i.e. the temperature at which liquid water is at equilibrium with solid water (ice) and gaseous water (steam) provided that the pressure is 610 Pa. 

Choosing spectra. For each substance, the spectra used to construct the calibration set should be from various batches so that physicochemical variability can be effectively incorporated. Not every spectrum recorded should be used to construct the library as some should be set aside for its validation. 

The term responsive (elsewhere indicated as smart ) refers to diagnostic agents whose contrasting properties are sensitive to a given physicochemical variable that characterizes the microenvironment in which the probe is distributed (116-117). Typical parameters of primary diagnostic relevance include pH, temperature, enzymatic activity, redox potential and the concentration of specific ions, and low-weight metabolites. 

The complex spatio-temporal mosaic of habitats in alpine river systems relates to the interaction of a range of physicochemical processes, with different processes dominating the river environment at different scales. Our new approach to alpine stream classification provides a basis to conceptualise this dynamic habitat template. The contributions from the different water sources have an important influence on the aquatic habitat template for the establishment of biotic communities, particularly through the effect on physicochemical variables outlined above. These include channel stability, water temperature and sediment regimes. Where alpine streams... 

In this example, the relation between 19 chemicals and 23 physicochemical parameters was examined ( ). PLS, unlike canonical correlation, permits use of more chemical parameters than stimuli. The twenty-three physicochemical variables included molecular weight, functional groups, Raman frequencies and Laffort parameters (see ( )) The Laffort parameters are alpha (an apolar factor proportional to molvolume), rho (a proton receptor factor), epsilon (an electron factor) and pi (a proton donor factor). 

Barra, J., and Somma, R. Influence of the physicochemical variability of magnesium stearate on its lubricant properties possible solutions. Drug. Dev. Ind. Pharm. 22 1105-1120. 1996. 

Table 6.4. PHYSICOCHEMICAL VARIABLES USED TO CHARACTERIZE THE AMINO...

Semifield tests offer the ability to observe or measure a suite of biological and physicochemical variables, as with the analysis of natural ecosystems. Usually, the focus is on structural measures such as the number of species and number of individuals per population (often lumped into higher taxonomic units), physicochemical parameters (e.g., dissolved oxygen, and pH including toxicant residues), and some microclimate parameters (e.g., evaporation in TMEs). 

G. Which Physicochemical Variables Affect Drug Incorporation into Hair ... 

In many cases, the performance of a combustion system can be quantified in terms of a few parameters, such as oxygen concentration and temperature of flue gases, pollutant emissions, steam production, and so on. However, these data may not be enough to describe the actual state of the combustion process. A clear example is the case of multiburner chambers, where global values do not represent necessarily the conditions at individual flames. Even for a single burner, bulk parameters (e.g., flue gas composition) can only afford a limited characterization of the flame. As it was pointed out in the introduction, a detailed description would require a vast amount of information in terms of the distributions in space (and maybe time) of many physicochemical variables. Imaging techniques are most valuable tools in this respect, since information on spatial patterns can be very helpful to describe, or even understand, important characteristics of a flame. 

Polaschegg E. Effect of physicochemical variables of regular insulin formulations on their absorption from the subcutaneous tissue. Diabetes Res Clin Pract 1998 40 39-44. 

Thus, this methodology can be useful in discovering physicochemical variables relevant to olfactory quality in that it strictly relates quantitative psychophysical measures with quantitative psychophysical chemical measures. 

Figure 7. Two-dimensional space regenerated from weighting the physicochemical variables shown in Table I in an attempt to reproduce the psychophysical space in...

Weights which were applied to standard scores for physicochemical variables to achieve the regenerated space in Fig. 7. Means and variances for these variables are also given. Functional groups are coded according to their number in a molecule thus, benzal-dehyde is coded "1" and the mean number of aldehyde groups for all the molecules in Fig. 7 is 0.10. Cyclic compounds are coded "1" while noncyclic coitpounds are coded "0."... 

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