Property kinetics

Li, J. and Carr, P.W., Effect of temperature on the thermodynamic properties, kinetic performance, and stability of polybutadiene-coated zirconia, Anal. Chem., 69(5), 837, 1997. 

D.W. Kraus and J.B. Wittenberg, Hemoglobins of the Lucina pectinata bacteria symbiosis I. Molecular properties, kinetics, and equilibria of reactions with ligands. J. Biol. Chem. 265, 16043—16053 (1990). 

Jong, A.Y.S. Campbell, J.L. Characterization of Saccharomyces cerevisiae thymidylate kinase, the CDC8 gene product. General properties, kinetic analysis, and subcellular localization. J. Biol. Chem., 259, 14394-14398 (1984)... 

Cheng, Y.C. Prusoff, W.H. Mouse ascites sarcoma 180 thymidylate kinase. General properties, kinetic analysis, and inhibition studies. Biochemistry, 12, 2612-2619 (1973)... 

Empirical approaches are useful when macroscale HRR measurements are available but little or no information is available regarding the thermophysical properties, kinetic parameters, and heats of reaction that would be necessary to apply a more comprehensive pyrolysis model. Although these modeling approaches are crude in comparison with some of the more refined solid-phase treatments, one advantage is that all required input parameters can be obtained from widely used bench-scale fire tests using well-established data reduction techniques. As greater levels of complexity are added, establishing the required input parameters (or material properties ) for different materials becomes an onerous task. 

Process dynamics and uncertainties are important issues for optimal design and operation of any processes. All process models are subject to uncertainties, e.g. in physical properties, kinetics, etc. 

There is a practical difference between exploring the chemical kinetics of a reaction and exploring "property kinetics the rate of change in a useful property of a complex material such as paper. The discipline of chemical kinetics has a sound theoretical foundation directly related to the mechanism of chemical reactions. Property kinetic studies, on the other hand, are empirical and are difficult to relate to chemical mechanisms. The difficulty arises because a complex property, such as tensile strength or brightness, cannot be related easily to the chemical composition of the material under study. Nevertheless, empirical rate constants can be obtained, and these rate constants can be related to chemical processes occurring within the paper. 

Most property kinetic studies reported in the literature are conducted by analogy with the methodology of chemical kinetics. A physical property, P, observed to change monotonically with time is assumed to obey a differential expression similar to a rate law in chemical kinetics. Equation 1 is a general expression of this kind where k is a constant and... 

If the property, F, monitored in a property kinetic experiment, is a function of chemical concentrations, C, in the paper, then a total differential of P with respect to time can be written (see Equations 10 and 11). 

In principle, if values of at could be determined n times throughout an accelerated aging experiment in which the empirical rate constant, k, is determined, then n simultaneous equations could be solved to yield the chemical rate constants, kt. However, in practice this is not feasible, and Equation 13 is of little analytical value. Nevertheless, our assumption that the property kinetic constant, k, is related linearly to chemical rate constants is verified. Thus, the apparent linearity of the empirical rate constant, kT in Equation 9, with respect to oxygen and acidity suggests the occurrence of chemical processes that are first order in oxygen and acidity. 

Evaluation of Degradation in Museum Textiles Using Property Kinetics... 

By comparison, paper conservators have addressed many of these same issues and may have been somewhat more cause oriented in dealing with specific treatments, such as deacidification, designed to reduce the rate of degradation. Arney and Chapdelaine have widely used the concept of property kinetics that is borrowed from chemistry where it was developed (II). 

The degradation reactions involved in the breakdown of cellulose are clearly highly complex, and thus the use of the concept of property kinetics is a bold simplifying analogy. In property kinetics most of the degradation processes are assumed to be temperature dependent. In addition, most or all of these processes are assumed to affect some useful macroscopic property such as tensile strength so that the individual effects of these processes can be subsumed into one unified effect that obeys the Arrhenius equation. Thus property kinetic studies are necessarily empirical and show a much less obvious or demonstrable mechanistic connection than chemical kinetic studies between the presumed cause and the measured effect. 

In artificial heat aging, property kinetics can be used in conjunction with the Arrhenius rate expression to estimate rate constants at room temperature provided the overall aging behavior, when monitored by a measurable parameter, can be shown to be constant over the temperature range of the study. 

Spectroscopic properties Kinetic properties Surface properties Mechanical properties... 

The measurement of transport properties, kinetics parameters, and physical properties is not an easy job. Bard and Faulkner [14] give a description of the experimental techniques that can be used to estimate electrochemical properties. 

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