REFINER model

Ramanathan P S and Friedman H L 1971 Study of a refined model for aqueous 1-1 electrolytes J. Chem. Phys. 54 1086... 

DPI Ohlendorf. Accuracy of refined protein structures. II. Comparison of four independently refined models of human interleukin 1(1. Acta Cryst 050 808-812, 1994. 

ISCST3 - Industrial Source Complex - Short Term This model is used in more detailed studies of maximum air quality impacts (Phase 3 - Refined Modeling Analysis). The purpose is to compute short term concentration or deposition values, from multiple sources, on specified locations (i.e., receptors). To download the file, click the filename. This is the latest version of the regulatory model ISCST3 (00101) which was released by U.S. EPA on April 27, 2000. The file ISCST.ZIP is 1.60 MB (Executable, Source, Test Cases). You can also download the ISCST3 model evaluation references. 

When the temperature of the analyzed sample is increased continuously and in a known way, the experimental data on desorption can serve to estimate the apparent values of parameters characteristic for the desorption process. To this end, the most simple Arrhenius model for activated processes is usually used, with obvious modifications due to the planar nature of the desorption process. Sometimes, more refined models accounting for the surface mobility of adsorbed species or other specific points are applied. The Arrhenius model is to a large extent merely formal and involves three effective (apparent) parameters the activation energy of desorption, the preexponential factor, and the order of the rate-determining step in desorption. As will be dealt with in Section II. B, the experimental arrangement is usually such that the primary records reproduce essentially either the desorbed amount or the actual rate of desorption. After due correction, the output readings are converted into a desorption curve which may represent either the dependence of the desorbed amount on the temperature or, preferably, the dependence of the desorption rate on the temperature. In principle, there are two approaches to the treatment of the desorption curves. 

Another concept has been developed on a refined model based on two-step redox systems typical for organic compounds This concept treats a polymer... 

The above problems of fabrication and performance present a challenging task of identification of the governing material mechanisms. Use of nonlinear finite element analysis enables close simulation of actual thermal and mechanical loading conditions when combined with measurable geometrical and material parameters. As we continue to investigate real phenomena, we need to incorporate non-linearities in behavior into carefully refined models in order to achieve useful descriptions of structural responses. 

There are therefore four adjustable parameters per atom in the refinement (xy, yy, Zj, By). In the computer experiments we have carried out to test the assumptions of the nucleic acid refinement model we have generated sets of observed structure factors F (Q), from the Z-DNA molecular dynamics trajectories. The thermal averaging implicit in Equation III.3 is accomplished by averaging the atomic structure factors obtained from coordinate sets sampled along the molecular dynamics trajectories at each temperature ... 

Fig. 5 shows the effects of the gas residence time on the hydrocarbon composition. The numerical simulation was carried out by the refined model. The calculated results are in good agreement with the experimental results. It should be noted that the measured gas composition only at a residence time of 20 ms was used for the parameter fitting. Nevertheless, the calculated hydrocarbon composition agrees with the experimental results at residence times shorter than 20 ms. 

Ramanathan, P. S. Friedman, H. L. (1971). Refined model for aqueous 1-1 electrolytes. Journal of Chemical Physics, 54, 1086-99. 

If the final structure either deviates from the refined model or does not match the NMR restraints (8) one has to revise the experimental data and the parameters used in the DG and MD computations (9). In many cases, mistakes are made when preparing and performing the computational processes (10) or even experimental errors might be present (11). Those errors include a wrong NMR peak assignment, no precise calibration of the NOE/ROE signals, an incorrect conversion of the experimental data to constraints, and a nonfactual parameterization of the rMD and fMD trajectories. In such cases either new calculations or new experiments must be performed. 

Physical and Chemical Properties. Most of the important physical-chemical properties of acrylonitrile have been determined (see Chapter 3). However, the partitioning of acrylonitrile between the air and water has been evaluated by using an estimated value for a Henry s law constant. This general approach assumes that the concentration of the chemical in water is low. Because acrylonitrile is relatively soluble in water, this approach may not be accurate. Experimental measurement of the partition coefficient for acrylonitrile at water-air interfaces would be useful in refining models on the behavior of acrylonitrile in the environment. 

For the discrete bubble model described in Section V.C, future work will be focused on implementation of closure equations in the force balance, like empirical relations for bubble-rise velocities and the interaction between bubbles. Clearly, a more refined model for the bubble-bubble interaction, including coalescence and breakup, is required along with a more realistic description of the rheology of fluidized suspensions. Finally, the adapted model should be augmented with a thermal energy balance, and associated closures for the thermophysical properties, to study heat transport in large-scale fluidized beds, such as FCC-regenerators and PE and PP gas-phase polymerization reactors. 

Although the resonant level model successfully explains a few general aspects of chemisorption, it has nevertheless many shortcomings. The model gives no information on the electronic structure of the chemisorption bond it does not tell where the electrons are. Such information is obtained from a more refined model, called the density functional method. We will not explain how it works but merely give the results for the adsorption of Cl and Li on jellium, reported by Lang and Williams [20]. 

Model refinement, then, means to establish the relationship between the more abstract model used to define postconditions and the more complex practical implementation. Retrieve functions translate from the refined model attributes to the abstract ones. 

Wolf-Gladrow, D. and Riebesell, U. (1997). Diffusion and reactions in the vicinity of plankton a refined model for inorganic carbon transport, Mar. Chem., 59, 17-34. 

Given the strong assumptions needed to model the joint PDF, the use of more refined models would not be justified. 

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