Biomedical subjects
Publications and source records attributed to H Soodak.
A brief summary is presented of the Gibbsian view of chemical drives and of its mechanical interpretation, including a description of the "diffusion force" that arises from an interplay between fluctuations and dissipation. Osmotic flows are shown to be driven by diffusion forces acting at the membrane interface, and not by the effects of Hammel and Scholander's "solvent tension."
This paper continues the development begun in Part I (15), to show in what way it is meaningful to reduce biological phenomena to physical theory at any level of organization. The appropriate level-independent physics is comprised of thermostatics, thermodynamics of irreversible processes, statistical mechanics, and nonlinear mechanics. Generalized, these approaches lead to a spectroscopic description of the constellation of periodic processes that constitute the living states. The spectroscopic description is here applied also to the inputs received by living systems, from lethal, high-energy, nuclear particles and radiation to low-energy communicational signals that make up languages understandable at the various levels in an hierarchical system. The concept of language is then itself generalized, showing how the empirical relation discovered by Zipf can be derived from a thermodynamic basis. It is demonstrated that certain linguistic and statistical-mechanical distribution functions can be related. Applications of the field thermodynamic approach to two problems in transport phenomena are given in APPENDIX I; applications of field thermodynamics to language and communication are given in APPENDIX II.
We present a tutorial on the mechanisms of and connections among osmosis, diffusion, and convection. For simplicity, we consider only two-component nonelectrolyte solutions under isothermal conditions. Further, we confine our attention to laminar convection with application to the case of flow through narrow channels, as might occur in membranes containing pores or slits. The application of equilibrium and near-equilibrium thermodynamics to flow processes is just like considerations of mechanics with friction, or hydrodynamics. The description of flow processes of more than two atomistic components, either solutions or suspensions, is identical in the dilute limit to the description we give, except possibly when the curvature of the flow field (at the velocity profile) is significant. Flow fields, therefore, naturally divide into three regimes: 1) "one-dimensional" flow fields, e.g., solutions or suspensions in extended regions, whose velocity profile is macroscopically flat (compared to the atomistic curvature); 2) flow fields with significant curvature, e.g., Poiseuille or turbulent fields; and 3) high curvature fields, e.g., narrow flow channels.