Complex Physico-chemical Analysis

From the complex physico-chemical analysis of the system LiF-KF-K2NbF7, it follows that the behavior and properties of the melts are affected by the formation of the congruently melting compound KsNbFg. Regarding the presence of the anion [NbFg] in the molten state the system behavior is not far from the ideal. 

From the theoretical point of view, on the basis of the complex physico-chemical analysis of these melts, considerations of their structure, i.e. the ionic composition was made. Using the multiple linear regression analysis, the equations describing molar volume and the surface tension on composition were obtained. From the individual interaction parameters, the formation of different structural entities in the melts was proposed. 

As an example for the first approach, the calculation of the dissociation degree of different additive compounds performed by Dandk and Proks (1999) can be mentioned. As an example for the second approach, the complex physico-chemical analysis of the system LiF-KF-K2NbF7-K20 performed by Danek et al. (2000a) can be cited. 

As there now exists a large body of laboratory studies on each of the variable systems, for example the effect of die lime/silica ratio in the slag on the desulphurization of liquid iron, the most appropriate phase compositions can be foreseen to some extent from these laboratory studies when attempting to optimize the complex indusuial process. The factorial uials are not therefore a shot in the dark , but should be designed to take into account die laboratory information. Any qualitative difference between die results of a factorial uial, and the expectations predicted from physico-chemical analysis might suggest the presence of a variable which is important, but which was not included in the nials. 

Stewart, L.,Manvell, M.,Hillery, E., Etheridge, C.J., Cooper, R.G., Stark, Et. etal. (2001) Physico-chemical analysis of cationic hposome-DNA complexes (hpoplexes) with respect to in vitro and in vivo gene delivery efficiency. J. Chem. Soc. Perkin Trans., 2, 624-632. 

Chrenkova et al. (1998) studied the structure or ionic composition of the melts of the system KF-KCl-KBF4-K2TiF6 based on the measurements of phase equilibria, density and viscosity and using complex thermodynamic and physico-chemical analysis. From the results of the physico-chemical analysis, it follows that deviations from the ideal behavior were observed in all boundary binary, ternary, as well as in the quaternary systems. With regard to the fact that the investigated system has a common cation, the observed deviations from the ideal behavior have to be a consequence of the anionic interaction only. 

The studies presented here are based essentially on the principle of comparison of the thermodynamic characteristics of adsorption measured on a number of organoderivatives of layer silicates and silica, with the data obtained from the molecular statistic calculations involving the portions of surface, which model the real surface of the materials studied. These surface portions were chosen on the basis of the adsorbent structure analysis and complex physico-chemical studies of the modifying layers structure. 

An understanding of the complex physico-chemical phenomena associated with the formation and behavior of cementitious compounds is facilitated through the application of many different types of investigative methods. Techniques such as NMR, XRD, neutron activation analysis, atomic absorption spectroscopy, IR/UV spectroscopy, electron microscopy, surface area techniques, pore characterization, zeta potential, vis-cometry, thermal analysis, etc., have been used with some success. Of the thermal analysis techniques the Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC), and Conduction Calorimetric methods are more popularly used than others. They are more adaptable, easier to use, and yield important results in a short span of time. In this chapter the application of these techniques will be highlighted and some of the work reported utilizing other related methods will also be mentioned with typical examples. 

The specific features of the cluster compounds of technetium are such, that practically each new compound must be studied using single crystal X-ray structural analysis, because their complex structures do not allow the interpretation of the results from other physico-chemical methods of investigation. Therefore, the synthesis of single crystals suitable for X-ray structural analysis is the main and most laborious chemical task. 

Obviously this procedure involves a lengthy and complex follow-up to the original analysis. Furthermore it is important to note that although the analytical results are objective measurements, the appraisal of their effectiveness in describing the emission, ultimately relies on subjective comparisons of odour sensation. This final observation could be interpreted as a weakness in the method in having to resort to subjective odour comparisons. An alternative viewpoint however is that the most effective information can be derived by utilising a combination of olfactometric and physico-chemical techniques. 

Brenguier et al. (2003) discussed the results of eight series of aircraft measurements of the microphysical characteristics of marine stratocumulus clouds in a broad range of observation conditions (different physico-chemical properties of aerosol, number density values in the interval 50 cm 3-25 cm-3, etc.)- The unique complex of synchronous observations of the microphysical and radiative characteristics of cloud cover obtained can be used to assess the indirect impact of aerosol on clouds and climate based on analysis of the ratio between the cloud optical thickness and effective radius of cloud droplets. Correlation between these values is usually negative, but in a heavily polluted atmosphere it can be positive. From the observational data obtained during ACE-2, the polluted systems of clouds turned out to be somewhat drier and therefore thinner, resulting in the positive correlation between the indirect impact of aerosol on climate and the effective radius of droplets. 

Simultaneously, extensive investigations concerning the physico-chemical properties of cryptands have been conducted covering several sub-topics their complexing properties, X-ray analysis, molecular dynamics of inclusion complexes, etc. 

In the preceding section the hyperfine parameters 6, A, H, and /) that can be extracted by spectral analysis were presented. These parameters have complex relationships with physico-chemical properties that are presented in a rather simplified manner in the following section, showing how local electronic, magnetic, structural, and chemical environments can be characterized. 

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