Physical model approach

Ho, N. F., Higuchi, W. I., Quantitative interpretation of in vivo buccal absorption of n-alkanoic acids by the physical model approach, /. Pharm. Sci. 1971, 60, 537-541. 

O. Physical Model Approach for Turbulent Mass Transfer near a Liquid-Fluid Interface... 

Drug Release Rate Behavior - Desai et al have reported results of extensive studies on the release of drug from matrices. Taking the basic physical model approach and beginning with the Higuchi relationship these authors have quantitatively investigated the influence of many factors upon the rate of release. The equation was also found by Lapidus and Lordi to apply to a system having hydrophillic gum as the matrix. 

Seta, A.H., Higuchi, W.I., Borsadia, S., Behl, C.R, and Malick, A.W. (1992). Physical model approach to understanding finite dose transport and uptake of hydrocortisone in hairless guinea pig skin. International Journal of Pharmaceutics, 81, 89-99. 

Because of the structural complexity and multi-physics character of modem DAFCs, an analysis through a consistent multiscale physical modeling approach is required to elucidate the efficiency limitations and their location, the degradation and failure mechanisms. 

Hofmann, Dissolution kinetics of gallstones Physical model approach, J.Pharm.Sci., 62 942 (1973). 

In a regression approach to material characterization, a statistical model which describes the relation between measurements and the material property is formulated and unknown model parameters are estimated from experimental data. This approach is attractive because it does not require a detailed physical model, and because it automatically extracts and optimally combines important features. Moreover, it can exploit the large amounts of data available. 

The physical model is thus that of a liquid him, condensed in the inverse cube potential held, whose thickness increases to inhnity as P approaches... 

Physical Models versus Empirical Models In developing a dynamic process model, there are two distinct approaches that can be... 

The comparison with experiment can be made at several levels. The first, and most common, is in the comparison of derived quantities that are not directly measurable, for example, a set of average crystal coordinates or a diffusion constant. A comparison at this level is convenient in that the quantities involved describe directly the structure and dynamics of the system. However, the obtainment of these quantities, from experiment and/or simulation, may require approximation and model-dependent data analysis. For example, to obtain experimentally a set of average crystallographic coordinates, a physical model to interpret an electron density map must be imposed. To avoid these problems the comparison can be made at the level of the measured quantities themselves, such as diffraction intensities or dynamic structure factors. A comparison at this level still involves some approximation. For example, background corrections have to made in the experimental data reduction. However, fewer approximations are necessary for the structure and dynamics of the sample itself, and comparison with experiment is normally more direct. This approach requires a little more work on the part of the computer simulation team, because methods for calculating experimental intensities from simulation configurations must be developed. The comparisons made here are of experimentally measurable quantities. 

To go from experimental observations of solvent effects to an understanding of them requires a conceptual basis that, in one approach, is provided by physical models such as theories of molecular structure or of the liquid state. As a very simple example consider the electrostatic potential energy of a system consisting of two ions of charges Za and Zb in a medium of dielectric constant e. 

Penner, D. E., Lehrer, R., Schauble, L. (1998). From physical models to biomechanics A design based modeling approach. The Journal of the Learning Sciences, 7, 429 149. 

In the approach of Dewar and co-workers (34), termed the half-electron method , a physical model is considered in which an unpaired electron is replaced by two hypothetical half-electrons of opposite spin. For radicals containing one unpaired electron, the eigenvalue problem of this method is, in our opinion, identical with the method of Longuet-Higgins and Pople (27) ... 

In the first chapter several traditional types of physical models were discussed. These models rely on the physical concepts of energies and forces to guide the actions of molecules or other species, and are customarily expressed mathematically in terms of coupled sets of ordinary or partial differential equations. Most traditional models are deterministic in nature— that is, the results of simulations based on these models are completely determined by the force fields employed and the initial conditions of the simulations. In this chapter a very different approach is introduced, one in which the behaviors of the species under investigation are governed not by forces and energies, but by rules. The rules, as we shall see, can be either deterministic or probabilistic, the latter leading to important new insights and possibilities. This new approach relies on the use of cellular automata. 

Narasinham, B Peppas, N, A, The Physics of Polymer Dissolution Modeling Approaches and Experimental Behavior, Vol, 128, pp. 157-208,... 

The advantage of the mixing tank model approach is its relative simplicity, intuitive accessibility, and easy correlation with pharmacokinetic models. However, the physical basis for considering a segment of the small intestine as one or more serial mixing tanks is limited, although such an assumption has been commonly and successfully utilized in the physical and biological sciences. 

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