Field intensification

Electric field measurement at the boundary of a metal container filled with charged material. Examples include pipelines and storage vessels. The electric field can be used to calculate charge density (3-5.1). Eield meters can also be lowered into containers such as silos to determine the local fields and polarities. Quantitative interpretation of the reading requires correction for field intensification and is sometimes accomplished using computer simulations. 

Similar analysis can be made for other types of materials. Thus, as a generalization, the curvature of a surface causes field intensification, which results in a higher current than that on a flat surface. Although the detailed current flow mechanism can be different for different types of materials under different potentials and illumination conditions, the effect of surface curvature on the field intensification at local areas is the same. The important point is that the order of magnitude for the radius of curvature that can cause a significant effect on field intensification is different for the substrates of different widths of the space charge layer. This is a principle factor that determines the dimensions of the pores. 

Depletion Layer and Field Intensification Model. By the mid-1980s the overall scope of the conditions for the formation of PS and of the various morphological features were largely identified, although many details of PS morphology and the... 

The electric field intensification in the surfactant-mediated separation processes is shown in Table In the feed, surfactant and metal ion concentrations are denoted by Csf and Cmf. respectively, while the corresponding concentrations in the permeate under steady-state conditions are denoted by C p and Cmp. Surfactant and metal ion rejections at a steady state are defined as Rs = (1-Csp/Csf) and Rm = (1-Cmp/Cmf)- The molar ratio of metal ion to surfactant is denoted by Fms- The separation of the electrodes is 3 mm. In Table 2, the initial current, pH, and solution conductivity are also given. It shows that both metal and surfactant are separated effectively under an electric field in which the permeate flux, surfactant, and metal ion rejections are enhanced. Economic analysis of the process indicates that some 20- to 50-fold efficiency increase is achieved compared with the no electric field case. For the process to be economical, low-solubility surfactants that can form multilamellar droplets should be used as carriers. 

The decreasing value of K with decreasing flaw size for fracture of IG-11 graphite suggests that the near crack tip failure criterion would be better expressed by combining the near crack tip stress intensification estimated by K with the far field applied stress, Sfraa(Eq. 28). Using simple superposition of the stress perpendicular... 

Trent, D. (2004) Chemical processing in high-gravity fields, in Re-Engineering the Chemical Processing Plant Process Intensification (eds A. Stankiewicz and J.A. Moulijn), Marcel Dekker Inc., New York, pp. 33-67. 

Micro-reaction technology can be one of the tools that process intensification may use [5]. Hence chemical micro processing and process intensification have a share, where the former supplies devices for the latter concept or purpose. However, both chemical micro processing and process intensification also cover imique aspects that the other field does not comprise. 

Strictly, chemical micro processing, in addition to being a device field based on micro channels, is a means to use micro flows, which is oriented not at one, but rather at a multitude of purposes. Process intensification, also strictly, is a concept (but specifying no concrete means) and apparatus for a specific purpose (see above). 

In chemical micro process technology there is a clear dominance of pressure-driven flows over alternative mechanisms for fluid transport However, any kind of supplementary mechanism allowing promotion of mixing is a useful addition to the toolbox of chemical engineering. Also in conventional process technology, actuation of the fluids by external sources has proven successful for process intensification. An example is mass transfer enhancement by ultrasonic fields which is utilized in sonochemical reactors [143], There exist a number of microfluidic principles to promote mixing which rely on input of various forms of energy into the fluid. 

From the very beginning, continuous reactor concepts, an alternative to the truly microfabricated reactors, were used, for example, static meso-scaled mixers or HPLCs and other smart tubing (see Iwasaki et al. 2006 for an example). This completed functionality by filling niches not yet covered by microfabricated reactors or even by replacing the latter as a more robust, more easily accessed or more inexpensive processing tool. Further innovative equipment, coming from related developments in the process intensification field, is another source e.g., structured packings such as fleeces, foams, or monoliths. 

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