Process transport phenomena effect

Microscale thermal transport phenomenon involves complex transfer mechanism of free electrons and phonons. The molecular dynamics and processes are not significant in most of the microscopic engineering applications. However, scale effects become extremely important in system with sudden high heat flux irradiation by laser pulses and some other dimensionally space- and time-governed problems. Anisimov etal. (1974) proposed the first two-step model for microscale conduction as... 

Bulk or forced flow of the Hagan-Poiseuille type does not in general contribute significantly to the mass transport process in porous catalysts. For fast reactions where there is a change in the number of moles on reaction, significant pressure differentials can arise between the interior and the exterior of the catalyst pellets. This phenomenon occurs because there is insufficient driving force for effective mass transfer by forced flow. Molecular diffusion occurs much more rapidly than forced flow in most porous catalysts. 

The binding process may exert a profound effect on cell function. It is well known that hepatic cells do not function when cultured on a flat plate. This reason may be partially explained by the binding-spreading phenomenon. It therefore follows that an ideal scaffold would minimize the spreading effect. Inasmuch as hepatic cells are our primary interest, a scaffold that best approaches the native shapes of the cells would appear to be the best. It is equally clear that this shape must be optimized against additional requirements of void volume and mass transport. Nevertheless, an ideal scaffold would be more curvilinear than flat. 

Sevastianov et al.73,74) have developed a model which considers the effect of surface heterogeniety on the adsorption process. They define centers of irreversible adsorption , labeled P, and centers of irreversible desorption , labeled D. They argue, in agreement with Soderquist and Walton, that desorbed material is conformationally altered and thus cannot readsorb — hence desorption is irreversible. The results of this model are given as Fig. 14, taken from Ref. 7J). The model also includes the case where adsorption may be transport limited. The model fits commonly observed adsorption data, including the overshoot phenomenon (Fig. 14, top) (discussed in Ref. 72)) to be discussed later. 

The key phenomenon revealing the most of the underlying physics is transport, where the effects of interactions play a crucial role. The processes of electron tunneling from grain to grain that govern electron transfer, are... 

The level of emissions of SO2 and N0X, and their effects in the United States and in other industrialized countries have been the target of considerable debate. When SO2 and N0X are emitted into the atmosphere, a large fraction of these pollutants can be oxidized to sulfate and nitrate during atmospheric transport, and then deposited as acidic compounds (4-8). Acid rain is the popular term to describe this complex phenomenon. Acidic compounds can be deposited in both wet and dry forms, and this process is more properly referred to as acid deposition or acid precipitation. The wet forms of acid deposition include rain, snow, fog, and dew. Dry deposition occurs via absorption of SO2 and N0X on surfaces and via... 

The static - double-layer effect has been accounted for by assuming an equilibrium ionic distribution up to the positions located close to the interface in phases w and o, respectively, presumably at the corresponding outer Helmholtz plane (-> Frumkin correction) [iii], see also -> Verwey-Niessen model. Significance of the Frumkin correction was discussed critically to show that it applies only at equilibrium, that is, in the absence of faradaic current [vi]. Instead, the dynamic Levich correction should be used if the system is not at equilibrium [vi, vii]. Theoretical description of the ion transfer has remained a matter of continuing discussion. It has not been clear whether ion transfer across ITIES is better described as an activated (Butler-Volmer) process [viii], as a mass transport (Nernst-Planck) phenomenon [ix, x], or as a combination of both [xi]. Evidence has been also provided that the Frumkin correction overestimates the effect of electric double layer [xii]. Molecular dynamics (MD) computer simulations highlighted the dynamic role of the water protrusions (fingers) and friction effects [xiii, xiv], which has been further studied theoretically [xv,xvi]. 

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