INDEX properties, selected

Shakoor, A. and Bonelli, R.E. 1991. Relationship between petrographic characteristics, engineering index properties and mechanical properties of selected sandstones. Bulletin Association Engineering Geologists, 28, 55-71. 

Consolidated Index of Selected Property Values Phys. Chem. and Thermodynamics, National Academy of Sciences, National Research Council, Publ. 976, Washington, D.C., 1962. 

Thermodex An Index of Selected Thermodynamic and Physical Property Resources http // www.lib.utexas.edu/thermodex/ (accessedNovember 10,2011). ThermoDex from the Mallet Chemistry Library, University of Texas-Austin is a freely searchable index to printed and Web-based compilations of thermochemical and thermophysical data. The ThermoDex home page also provides a guide to Finding Thermodynamic Information/Where to Start, which lists some of the standard handbooks and proprietary databases that are not indexed as well as those that are indexed. Searches for compounds, or preferably compound types, linked to a specific physical property or properties, display a list of handbooks that may contain data of interest. Actual data values are not displayed. ThermoDex records include the book s title, a brief abstract defining the scope and arrangement, properties and types of compounds, etc. Web datasets include URL links. While based primarily on the holdings of UT-Austin s Mallet Chemistry Library, most of these resources will be available in most university and major industrial libraries. 

ThermoDex An Index of Selected Thermodynamic Data Handbooks http //ww w.lib.utexas. edu/thennodex/ (accessed September 30, 2010). Austin, TX Mallet Chemistry Library, University of Texas at Austin. This database contains records for selected printed and Web-based compilations of thennochemical and thermophysical data. Searching for properties linked to types of compounds will return lists of sources that may contain the data. 

The most appropriate stabilizer combination will depend on the selection of other formulation ingredients, as well as on the accelerated aging test conditions, and on the properties selected as indexes of product stability. 

Chakactkrisation of Unsaturatkd Aliphatic Hydrocarbons Unlike the saturated hydrocarbons, unsaturated aliphatic hydrocarbons are soluble in concentrated sulphuric acid and exhibit characteristic reactions with dUute potassium permanganate solution and with bromine. Nevertheless, no satisfactory derivatives have yet been developed for these hydrocarbons, and their characterisation must therefore be based upon a determination of their physical properties (boiling point, density and refractive index). The physical properties of a number of selected unsaturated hydrocarbons are collected in Table 111,11. 

Solvents exert their influence on organic reactions through a complicated mixture of all possible types of noncovalent interactions. Chemists have tried to unravel this entanglement and, ideally, want to assess the relative importance of all interactions separately. In a typical approach, a property of a reaction (e.g. its rate or selectivity) is measured in a laige number of different solvents. All these solvents have unique characteristics, quantified by their physical properties (i.e. refractive index, dielectric constant) or empirical parameters (e.g. ET(30)-value, AN). Linear correlations between a reaction property and one or more of these solvent properties (Linear Free Energy Relationships - LFER) reveal which noncovalent interactions are of major importance. The major drawback of this approach lies in the fact that the solvent parameters are often not independent. Alternatively, theoretical models and computer simulations can provide valuable information. Both methods have been applied successfully in studies of the solvent effects on Diels-Alder reactions. 

A simplified performance index for stiffness is readily obtained from the essentials of micromechanics theory (see, for example. Chapter 3). The fundamental engineering constants for a unidirectionally reinforced lamina, ., 2, v.,2, and G.,2, are easily analyzed with simple back-of-the-envelope calculations that reveal which engineering constants are dominated by the fiber properties, which by the matrix properties, and which are not dominated by either fiber or matrix properties. Recall that the fiber-direction modulus, is fiber-dominated. Moreover, both the modulus transverse to the fibers, 2, and the shear modulus, G12. are matrix-dominated. Finally, the Poisson s ratio, v.,2, is neither fiber-dominated nor matrix-dominated. Accordingly, if for design purposes the matrix has been selected but the value of 1 is insufficient, then another more-capable fiber system is necessary. Flowever, if 2 and/or G12 are insufficient, then selection of a different fiber system will do no practical good. The actual problem is the matrix systemi The same arguments apply to variations in the relative percentages of fiber and matrix for a fixed material system. 

As 1,2,5-thiadiazole analogues, potent HlV-1 reverse transcriptase inhibitors, some simple 1,2,5-oxadiazoles, compounds 4-6 (Fig. 9), have been synthesized using the traditional Wieland procedure as key for the heterocycle formation [121]. Such as thiadiazole parent compounds, derivative with chlorine atoms on the phenyl ring, i.e., 5, showed the best anti-viral activity. Selectivity index (ratio of cytotoxic concentration to effective concentration) ranked in the order of 5 > 6 > 4. The activity of Fz derivative 6 proved the N-oxide lack of relevance in the studied bioactivity. These products have been claimed in an invention patent [122]. On the other hand, compound 7 (Fig. 9) was evaluated for its nitric oxide (NO)-releasing property (see below) as modulator of the catalytic activity of HlV-1 reverse transcriptase. It was found that NO inhibited dose-dependently the enzyme activity, which is hkely due to oxidation of Cys residues [123]. 

The dielectric constant and refractive index parameters and different functions of them that describe the reactive field of solvent [45] are insufficient to characterize the solute-solvent interactions. For this reason, some empirical scales of solvent polarity based on either kinetic or spectroscopic measurements have been introduced [46,47]. The solvatochromic classification of solvents is based on spectroscopic measurements. The solvatochromic parameters refer to the properties of a molecule when its nearest neighbors are identical with itself, and they are average values for a number of select solutes and somewhat independent of solute identity. 

The HcReynolds system of phase constants has become the most widely used systematic approach to solvent selectivity characterisation and virtually all pedlar phases have been characterized by this method. In spite of its popularity the approach is fundamentally flawed and the phase constants are an unreliable indication of i ase properties. The basic approach, however, has influenced the development of other methods of selectivity characterization, and although these methods have inherited many of the deficiencies of their parent, a brief description of the HcReynolds approach is worthwhile to. idicate the general limitations of methods based on retention index differences. 

The HcReynolds abroach, which was based on earlier theoretical considerations proposed by Rohrschneider, is formulated on the assumption that intermolecular forces are additive and their Individual contributions to retention can be evaluated from differences between the retention index values for a series of test solutes measured on the liquid phase to be characterized and squalane at a fixed temperature of 120 C. The test solutes. Table 2.12, were selected to express dominant Intermolecular interactions. HcReynolds suggested that ten solutes were needed for this purpose. This included the original five test solutes proposed by Rohrschneider or higher molecular weight homologs of those test solutes to improve the accuracy of the retention index measurements. The number of test solutes required to adequately characterize the solvent properties of a stationary phase has remained controversial but in conventional practice the first five solutes in Table 2.12, identified by symbols x through s have been the most widely used [6). It was further assumed that for each type of intermolecular interaction, the interaction energy is proportional to a value a, b, c, d, or e, etc., characteristic of each test solute and proportional to its susceptibility for a particular interaction, and to a value x, X, Z, U, s, etc., characteristic of the capacity of the liquid phase... 

Our goal is to estimate the function P(r) from the set of discrete observations Y(tj). We use a nonparametric approach, whereby we seek to estimate the function without supposing a particular functional form or parameterization. We require that our estimated function be relatively smooth, yet consistent with the measured data. These competing properties are satisfied by selecting the function that minimizes, for an appropriate value of the regularization parameter X, the performance index ... 

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