Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Induction parameter model calculations

Marriott and Topsom have recently developed theoretical scales of substituent field and resonance parameters. The former correspond to the traditional inductive parameters but these authors are firm believers in the field model of the so-called inductive effect and use the symbol The theoretical substituent field effect scale is based on ab initio molecular orbital calculations of energies or electron populations of simple molecular systems. The results of the calculations are well correlated with Op values for a small number of substituents whose Op values on the various experimental scales (gas-phase, non-polar solvents, polar solvents) are concordant, and the regression equations are the basis for theoretical Op values of about 50 substituents. These include SOMe and S02Me at 0.37 and 0.60 respectively, which agree well with inherent best values in the literature of 0.36 and 0.58. However, it should be noted that a, for SOMe is given as 0.50 by Ehrenson and coworkers . [Pg.517]

There are five adjustable parameters per molecule X, the dispersion parameter q, the induction parameter x, the polarity parameter a, the hydrogen-bond acidity parameter and p, the hydrogen-bond basicity parameter. The induction parameter q often is set to a value of 1.0, yielding a four-parameter model. The terms fj and are asymmetry factors calculated from the other parameters. A database of parameter values for 150 compounds, determined by regression of phase equilibrium data, is given by Lazzaroni et al. [Ind. Eng. Chem. Res., 44(11), pp. 4075-4083 (2005)]. An application of MOSCED in the study of liquid-liquid extraction is described by Escudero, Cabezas, and Coca [Chem. Eng. Comm., 173, pp. 135—146 (1999)]. Also see Frank et al., Ind. Eng. Chem. Res., 46, pp. 4621-4625 (2007). [Pg.34]

Modeling of High-Speed Interconnections. Modeling the electrical behavior of an interconnection involves two steps. First, the transmission line characteristics, such as the characteristic impedance, propagation constant, capacitance, resistance, dielectric conductance, and coupling parameters, must be calculated from the physical dimensions and material properties of the interconnection. In addition, structures, such as wire bonds, vias, and pins, must be represented by lumped resistance (R), inductance (L), and capacitance (C) elements. [Pg.471]

The changes (against time) of Q02 have been calculated for PE at different temperatures, with the parameter values reported in Table I, and compared to literature data (13). At temperatures higher than 100°C, good agreement has been obtained between theory and experiment (Figure 2). However, at temperatures lower than 100°C, deviations have been observed the core of the model overestimates the oxidation induction time tj and underestimates the maximum oxidation rate rs, both deviations increasing when the temperature decreases. [Pg.149]

Oran et al. [218,219] developed a global parameterized model which describes the chemical induction time as a function of temperature and pressure. Parameters of the induction time function were determined for stoichiometric hydrogen and methane in air mixtures. The parameters were fitted to numerical results obtained from the simulations based on detailed reaction mechanisms. This technique allowed a 22-times faster calculation of the induction time and reduced the simulation time in a onedimensional model by a factor of 7.5. The fitted model was used in two-dimensional shock-wave simulations. [Pg.409]

Vanadium molecular size distributions in residual oils are measured by size exclusion chromatography with an inductively coupled plasma detector (SEC-ICP). These distributions are then used as input for a reactor model which incorporates reaction and diffusion in cylindrical particles to calculate catalyst activity, product vanadium size distributions, and catalyst deactivation. Both catalytic and non-catalytic reactions are needed to explain the product size distribution of the vanadium-containing molecules. Metal distribution parameters calculated from the model compare well with experimental values determined by electron microprobe analysis, Modelling with feed molecular size distributions instead of an average molecular size results in predictions of shorter catalyst life at high conversion and longer catalyst life at low conversions. [Pg.282]

When one can evaluate the energy of an adsorbed molecule in an arbitrary position near the surface of amorphous oxide, one may begin to calculate the adsorption characteristics of that surface. It is simpler to do that when the concentration of adsorbed molecules at the surface is infinitely small, i.e., in the Henry s Law region. Even in this case, calculations are usually carried out only for spherically synunetric molecules like rare gases or spherical models of more complex molecules like CH4 and SFe, the only exception being Ref. [19] where SFe was represented by a six-center model. In all cases the interaction of an adsorbed molecule with the oxide was modeled by LJ-potentials, the induction interaction being implicitly taken into account by the values of the parameters of the potential. [Pg.346]

Wan] Electrolytic Co (99.99%), Fe (99.99%), Mo (99.5%). Melting in alumina crucibles in a high induction furnace under an Ag atmosphere. Hot-rolling at 800 °C. Optical microscopy, SEM/energy dispersive X-ray analysis. Thermodynamic calculations with the Redlich-Kister model and thermodynamic parameters evaluated with the PARROT software. The alloys of the compositions near Cu/ Fe 50/50 with Mo from 0 to 6 mass%. Annealing at 800 to 1300°C for 3 to 1680 h. Experimentally determined compositions of the phases in equilibrium at 1300, 1200, 1100, 1000, 900, 800°C. Calculated isothermal sections at 1500, 1300, 1100, 900°C vertical sections at 5 and 10 mass% Mo and up to 30 mass% Cu metastable miscibility gap of the liquid phase. [Pg.460]

In order to calculate equivalent impedance of the sample, conductance as another dominant electrical parameter shuold be taken into account. It is a parasitic parameter that is given in terms of capacitance with tanS as a measure of losses, i.e., l/R=G-o>C tan5. The intergranular impedance model also contains two additional parameters inductance L, and capacitance Cp. Their nature cannot be correlated with geometrical parameters of grains in general way. [Pg.84]


See other pages where Induction parameter model calculations is mentioned: [Pg.517]    [Pg.133]    [Pg.161]    [Pg.457]    [Pg.88]    [Pg.292]    [Pg.329]    [Pg.1944]    [Pg.240]    [Pg.318]    [Pg.503]    [Pg.505]    [Pg.239]    [Pg.96]    [Pg.56]    [Pg.245]    [Pg.133]    [Pg.30]    [Pg.57]    [Pg.438]    [Pg.409]    [Pg.149]    [Pg.286]    [Pg.180]    [Pg.1944]    [Pg.212]    [Pg.209]    [Pg.154]    [Pg.140]    [Pg.505]    [Pg.507]    [Pg.78]    [Pg.166]    [Pg.75]    [Pg.462]    [Pg.184]    [Pg.228]    [Pg.462]    [Pg.153]    [Pg.272]    [Pg.436]   
See also in sourсe #XX -- [ Pg.90 ]




SEARCH



Inductance calculation

Induction parameter

Induction parameter model

Inductive parameter

Model calculations

Model parameter

Parameter calculation

© 2024 chempedia.info