Flow, fluid compartmentalization

One way to ease any difficulties that may arise in fabricating a membrane, especially in design configurations that are not planar, is to go membraneless. Recent reports take advantage of the laminar flow innate to microfluidic reactors ° to develop membraneless fuel cells. The potential of the fuel cell is established at the boundary between parallel (channel) flows of the two fluids customarily compartmentalized in the fuel cell as fuel (anolyte) and oxidant (catholyte). Adapting prior redox fuel cell chemistry using a catholyte of V /V and an anolyte of Ferrigno et al. obtained 35 mA cmr at... 

These simple models based on the assumption of a single intestinal compartment have been refined to the advanced compartmental absorption and transport model that allows transit and differential expression of enzymes and transporters down the length of the gastrointestinal tract including pH, fluid, and blood flow differences [3]. The ACAT model is based on a series of integrated differential equations and has been implemented in the commercial software Gastroplus (see Chapter 17). 

Type 3 and some type 1 tabular units are often laterally extensive, in some cases extending for over 2 km (see Fig. 7). These units would form significant barriers to vertical fluid flow, perhaps resulting in compartmentalization of the reservoir/aquifer. Such compartmentalization can result in dramatically reduced production if wells are screened on... 

Fracturing and fault compartmentalization of sandstones fundamentally affects reservoir properties and may significantly influence the fluid migration pathways in a basin (Knipe, 1993). Open fractures may form high-permeability conduits, whereas cement-sealed fractures form barriers to fluid flow. Seismic, petrophysical and reservoir performance data allow regional (field-scale) effects of faulting on fluid flow to be constrained. However, much fracturing and associated cementation may occur at sub-... 

The presence of different fluid properties in different parts of a reservoir may result from compartmentalization, reflecting the inability of fluid variations to mix over geological timescales due to the presence of flow barriers. 

Subsequent reservoir geochemical studies using high resolution GC fingerprinting have confirmed the validity and usefulness of the charge model. More importantly, it has allowed a better understanding of compartmentalization within the field and which faults may or not prove to be barriers to fluid flow on a production timescale. 

Fluids that are of interest in nature, biotechnology and chemistry, are rarely simple singlephase fluids. Most compartmental chemistry, interfacial phenomena, and applications employ two-phase flows. It is therefore not surprising that recently a surge of interest has arisen in two-phase microfluidic manipulation. 

Most actual reactors deviate from these idealized systems primarily because of nonuniform velocity profiles, channeling and bypassing of fluids, and the presence of stagnant regions caused by reactor shape and internal components such as baffles, heat-transfer coils, and measurement probes. Disruptions to the flow path are common when dealing with heterogeneous systems, particularly when solids are present. To model these actual reactors, various regions are compartmentalized and... 

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