Physicochemical processes, conceptual

Figure 1. Conceptual model of the important physicochemical processes, leading to the uptake of a trace element by an aquatic microorganism...

Concepts and terminology of adsorption processes on solid adsorbents are discussed by D. H, Everett, Reporting data on adsorption from solution at the solid/solution interface, Pure Appl. Chem. 58 967 (1986). See also D. H. Everett, Manual of Symbols and Terminology for Physicochemical Quantities and Units. Appendix II Definition, Terminology and Symbols in Colloid and Surface Chemistry, Butterworths, London, 1972 [published in Pure Appl. Chem. 31 577 (1972)]. The need for a relative definition of the amount of adsorbed substance stems from the fact that the actual position of an interface cannot be specified with absolute precision, even conceptually. 

Both Bayer and InfraServ Knapsack carry out similar projects in their design departments. A project can include conceptual process design as well as basic and detail engineering. For the modeling, simulation, and optimization of chemical processes, several tools like CHEMCAD [592] or Aspen Plus [516] are used. In addition, laboratory experiments may be required to determine reaction parameters or other physicochemical data. A project can also include the planning, construction, operation, and analysis of a pilot plant. Depending on the customer s demands, not all of these project phases are executed. 

Brumley BH, Jirka GH (1988) Air-water transfer of slightly soluble gases turbulence, interfacial processes and conceptual models. PhysicoChem Hydrodyn 10 295-319... 

In this chapter, both a set of physicochemical conceptual assumptions used in model simplification and a set of mathematical tools for this purpose are presented. First, we are going to explain physicochemical concepts of simplifications using models of chemical transformations. In this case, the transport processes are considered to be fast, and the models consist of ordinary differential equations (non-steady-state processes) or algebraic equations (steady-state processes). 

Conceptually, the problem of quantifying molecular diversity involves two parts the first is the definition of chemical distance, and the second is the selection of a representative set of compounds from a (typically) much larger collection. This section reviews a number of methods that have been proposed to encode molecular structures in a way that is suitable for numerical processing. It is organized in three parts, which discuss descriptors derived from the topology, three-dimensional structure, and physicochemical and electronic properties of the molecules. 

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