Apparent solution

A design concept is simply selected from a class of known design concepts in the problem domain. For example, three types of doors are well known, and one of these types is selected and patented. 

A design concept is developed through the modification of a known concept or through the combination of two known concepts in the problem 

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Local ordering effects have long been recognised experimentally in measurements of dipole moments of polar solutes in non-polar solvents, where the value obtained on the basis of the simple model differs from the value obtained for the pure solute in the gas phase, even when the results are extrapolated to infinite dilution. This so-called solvent effect is due to the Onsager reaction field. If there is no strong local ordering, Onsager s formula (2.52) is valid and the apparent solution moment is related to the isolated molecule or gas moment by... 

Site-competition delocalization manifests itself in two ways (a) an increase in the apparent solute molecular size, or value of A, in Eq. (8) and... 

Small amounts of a red crystalline solid wtre obtained at this point by the checkers in several runs. This substance can be converted to o-hydrazinobenzoic acid by the addition of 5 ml. of concentrated hydrochloric acid to a suspension of 1 g. of the solid in 25 ml. of dilute (1 1) hydrochloric acid. The red solid changes to the white o-hydrazinobenzoic acid hydrochloride without apparent solution. 

The first requirement can be easily fulfilled by the preconcentration of the analyte before the analysis. Preconcentration has been applied to sample preparation for flame atomic absorption (25) and, more recently, for ICP (79,80) spectroscopy. However, preconcentration is not completely satisfactory, because of the increased analysis time (which may be critical in clinical analysis) and the increased chance of contamination or sample loss. Most important, however, a larger initial sample size is necessary. The apparent solution is a more sensitive technique. Table 2 lists concentrations of various metals in whole blood or serum (81,82) in comparison to limits of detection for the various atomic spectroscopy techniques. In many cases, especially for the toxic heavy metals, only flameless atomic absorption using a graphite furnace can provide the necessary sensitivity and accommodate a sample of only a few microliters (Table 1). The determination of therapeutic gold in urine and serum (83,84), chromium in serum (85), skin (86) and liver (87), copper in semen (88), arsenic in urine (89), manganese in animal tissues (90), and lead in blood (91) are but a few examples in analyses which have utilized the flameless atomic absorption technique. 

The problems in this example have no easy solution. DDT use began as the apparent solution to a long-time scourge, but the success was short-lived. The challenge for chemical scientists now is to find new approaches to preventing or curing the disease—but without harmful effects elsewhere in the environment. 

Total copper and cadmium concentrations increased from Sites 1-4, ranging from 1.2 to 6.8 /xg/L for copper, and 0.2 to 1.0 /xg/L for cadmium. Copper transported in the dissolved phase ranged from 56% at Site 4 to 68% at Sites 1 and 3, and 80% at Site 2. Dissolved cadmium accounted for more than 50% of the total concentrations at all sites. Thus, copper and cadmium transport in the Mississippi River was dominated by apparent solution-phase transport. Total mean lead concentrations ranged from 2.3 to 5.7 /xg/L at Sites 1-4, with dissolved metal accounting for 16 to 38% of the total. The unexpectedly large contribution of dissolved lead indicates the potential role played by organic matter in maintaining lead in solution. 

The magnitude of the difference in temperature between the exterior and the interior of the sample depends upon two factors the rate of heating (as in TG), and the thermal conductivity of the sample and sample holder. Thus, a metal sample (which has a high thermal conductivity) is close to isothermal, even at high rates of heating. An apparent solution to the problem of thermal equilibrium is to increase the thermal conductivity of the sample appreciably (for instance, by mixing it with a diluent of high conductivity). This approach has limitations, however Equation... 

Species variations that may seriously affect the validity of laboratory animal metabolism studies as predictive models for man are a problem without apparent solution. For proper evaluation of the toxicological significance of pesticides to man, metabolism... 

A change in conformation affects the apparent solute molecular weight versus M) as described eariier, so that for denatured proteins [Eq. (59)] can be substituted for M in Eq. (61). This assumes that and SEC retention are each determined by the Stokes diameter of the molecule (see discussion of Ref. 12). 

Values Eh measured using standard electrode include some error. Apparently, solutions with high Eh play the role of oxidant relative to the solutions with low Eh. However, this does not mean that all redox reactions of the solution are in equilibrium and all of them have equal values of oxidation-reduction potential. For instance, in the solution with Fe and dissolved can run two semi-reactions... 

A charged particle in solution will become mobile when placed in an elecfric field. The velocity, Vi, acquired by the solute under the influence of the applied voltage H, is the product of p,app, the apparent solute mobility, and the applied field E (E = HIL, where L is the length of the fieldr ... 

In equation (8), r is the apparent solution viscosity, Hq the zero shear viscosity, and is the shear rate. The characteristic molecular response time, X, is defined by equation (3) when the shielding factor is one. In equation (8), the terms in the bracket can be approximated by two series expansions. 

Equation (14) can be used to determine the molecular response time and the zero shear viscosity by plotting the apparent solution viscosity versus the cube of the shear stress. From a linear regression analysis of viscometer data, an intercept, a, and slope, b, can be determined. The intercept is equal to the zero shear viscosity, and the molecular response time is a function of the slope and intercept. 

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