Experiments indirect methods

The Institute has many-year experience of investigations and developments in the field of NDT. These are, mainly, developments which allowed creation of a series of eddy current flaw detectors for various applications. The Institute has traditionally studied the physico-mechanical properties of materials, their stressed-strained state, fracture mechanics and developed on this basis the procedures and instruments which measure the properties and predict the behaviour of materials. Quite important are also developments of technologies and equipment for control of thickness and adhesion of thin protective coatings on various bases, corrosion control of underground pipelines by indirect method, acoustic emission control of hydrogen and corrosion cracking in structural materials, etc. 

These simulation data should be proved by experiment. However, it is still unknown that what microorganisms are PAOs or GAOs. Therefore the precision of model for EBPR process should be determined with indirect methods. Then with the concentration decrease of PAOs, the GAOs concentration was increased rapidly. However, this simulation result shoidd be supported by the experimental data with the identification of PAOs and GAOs. 

Immunogold labeling with JIM S exhibited an identical labeling distribution for polygalacturonic acid as was obtained indirectly with the EPG EMSIL (inset of Fig. 1). Control experiments for labeling specificities obtained by the direct or indirect methods resulted in total elimination of specific labeling. The cellulase-gold probe heavily labeled the epidermal cell walls (Fig. 2). 

As in spectroscopy, there are two ways of imaging 15N (and 14N), the direct and the indirect method. In the direct mode the simplest enhancement is available with N HJd.r. experiments in which the Overhauser effect is used to advantage. The maximum value of the effect is —3.93 for 1 H 15N. The NOE is negligible for 14N, as we have seen already. 

The CIDNP method is an indirect method since the hyperfine pattern of a paramagnetic intermediate is derived from the unusual NMR intensities of a diamagnetic product derived from it. This method also has limitations and potential sources of misassignments. Similar to the EPR technique, the CIDNP method only documents the unpaired spin additional evidence for the nature of the paramagnetic intermediate, particularly for the presence of the charge, is derived typically on the basis of mechanistic considerations and from supporting secondary experiments. 

Indirect methods for obtaining information on the kinetics of the associa-tion/dissociation equilibrium include sedimentation velocity and GPC experiments. The application of these techniques is based on comparison of sedimentation or GPC elution curves with model curves based on theories for separation of unimers and micelles during a sedimentation velocity (Gilbert 1955) or GPC (Ackers and Thompson 1965 Coll 1971 Prochazka et at. 1988, 1989) experiment. Experiments have been performed that demonstrate several of the qualitative model predictions (Prochazka et at. 1989). The main conclusions were that GPC curves with two well-separated peaks can only result from a slow dynamic molecule micelle equilibrium, and that no simple interpretation of elution curves in terms of relative concentrations of unimer and micelles is possible (Prochazka et at. 1989). Thus no quantitative information on the kinetics of the molecule micelle equilibrium can be obtained from sedimentation velocity or GPC data. 

Speciation of Dissolved Species. Since there is no straightforward method to identify the dissolved species in solubility experiments, indirect approaches were applied in this experiment. 

Since crushed basalt has been recommended as a major backfill component (1), experiments were completed to evaluate the rate of dissolved oxygen consumption and the redox conditions that develop in basalt-water systems under conditions similar to those expected in the near-field environment of a waste package. Two approaches to this problem were used in this study (l)the As(III)/As(V) redox couple as an indirect method of monitoring Eh and (2) the measurement of dissolved oxygen levels in solutions from hydrothermal experiments as a function of time. The first approach involves oxidation state determinations on trace levels of arsenic in solution (4-5) and provides an estimate of redox conditions over restricted intervals of time, depending on reaction rates and sensitivities of the analyses. The arsenic oxidation state approach also provides data at conditions that are more reducing than in solutions with detectable levels of dissolved oxygen. 

An indirect method of determining pK values, frequently applied in biochemical experiments, is to use pH-dependent kinetic assays and to relate rate profiles of reactions with pH. However, it can be difficult to unambiguously assign the acid-base equilibrium to a specific process (34c). 

Photosystem II reaction centres have been shown to be located mainly in the appressed granal membranes by a number of independent but indirect methods, including thylakoid fractionation, de-stacking and re-stacking experiments and chemical modification. Further evidence has come from freeze-fracture investigations of mutants specifically deficient in photosystem II in barley (Simpson et al., 1977), tobacco (Miller and Cushman, 1979) and Chlamydomonas (Olive etal. 1979). In all cases, there was a partial or almost... 

The first estimate of the Bk(IV)-Bk(III) potential was made in 1950, only a short time after the discovery of the element. A value of 1.6 V was reported, based on tracer experiments (3). Later, in 1959, a refined value of 1.62 0.01 V was reported for the couple, based on the results of experiments with microgram quantities of berkelium (4). The potential of the Bk(IV)-Bk(III) couple has subsequently been determined by several workers using direct potentiometry (220-224) or indirect methods (218, 225, 226). All of the above-mentioned determinations were performed in media of relatively low complexing capability. The formal potential of the Bk(IV)—Bk(III) couple is significantly shifted to less positive values in media containing anions that strongly complex Bk(IV), such as PCV- and CO32- ions (227). This behavior closely parallels that of the Ce(IV)-Ce(III) couple (228). In fact, the Bk(IV)-Bk(III) couple markedly resembles the Ce(IV)-Ce(III) couple in its oxidation-reduction chemistry. 

Therefore, for low-molar-mass substances Ecoh can easily be calculated from the heat of evaporation or from the course of the vapour pressure as a function of temperature. As polymers cannot be evaporated, indirect methods have to be used for the determination of their cohesive energy, e.g. comparative swelling or dissolving experiments in liquids of known cohesive energy density. The method is illustrated in Fig. 7.1. 

Another indirect method for the estimation of Gibbs elasticity modulus is based on the determination of the surface dilatation modulus E in experiments in which the surfaces of the surfactant solutions undergo small amplitude deformations of oscillatory nature [100-102], It is shown [100, see also Chapter 7] that the concentration dependence of a Gibbs elasticity modulus at constant film thickness should be nearly the same as the concentration dependence of (twice) the surface elastic modulus E when film thickness and frequency are related by... 

Radical polymerizations are almost always considered as kinetically stationary. However, the stationarity conditions are not always fulfilled. Living polymerizations with rapid initiation are stationary, but the character of the medium should not significantly change during polymerization in order to prevent shifts in the equilibria between ion pairs and free ions. All other polymerizations are non-stationary even, to some extent, living polymerizations with slow initiation. It is usually very difficult to define initiation and termination rates so as to permit exact kinetic analysis. When the concentration of active centres cannot be directly determined, indirect methods must be applied, and sometimes even just a trial search for best agreement with experiment. 

In the calculation of total pressure and vapor composition from boiling point data using the indirect method, the greatest source of error lies in the liquid-phase composition. We have attempted to characterize the frequency distribution of the error in the calculated vapor composition by the standard statistical methods and this has given a satisfactory result for the methanol- vater system saturated with sodium chloride when the following estimates of the standard deviation were used x, 0.003 y, 0.006 T, 0.1° C and tt, 2 mm Hg. This work indicates that in the design of future experiments more data points are required and, for each variable, a reliable estimate of the standard deviation is highly desirable. 

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