Particles surface area/volume

Liquid-solid mass transfer is typically not limiting due to the small particle size resulting in large particle surface area/volume of reactor, unless the concentration of the particles is very low, and or larger particles are used. In the latter case, intraparticle mass-transfer limitations would also occur. Ramachandran and Chaudhari (Three-Phase Catalytic Reactors, Gordon and Breach, 1983) present several correlations for liquid-solid mass transfer, typically as a Sherwood number versus particle Reynolds and Schmidt numbers, e.g., the correlation of Levins and Glastonbury [Trans. Inst. Chem. Engrs. 50 132 (1972)] ... 

Here as is, for instance, the external particle surface area/volume of reactor. Eliminating the surface concentration C0 in terms of the observable bulk gas concentration C yields the overall specific rate of consumption of A ... 

There are a large number of transformation models which can be used to analyze the image dimensional parameters in the determination of particle shape. Some methods require additional information of particle surface area, volume or thickness to give better estimates of shape but for most purposes, a simple approach is often preferred. The common treatment of data, namely, breadth, length, perimeter, and area to reflect the particle shape (1,2) is given as follows ... 

Surfa.ce, Any reaction between two powder particles starts on the surface. The amount of surface area compared to the volume of the particle is, therefore, an important factor in powder technology. The particle—surface configuration, whether it is smooth or contains sharp angles, is another. The particle surface area depends strongly on the method of production, as shown in Table 1. The method of production usually determines the particle shape. 

At high Reynolds numbers the friction factor becomes nearly constant, approaching a value of the order of unity for most packed beds. In terms of S, particle surface area per unit volume of bed,... 

Surface area of the sphere with same volume as particle Surface area of the particle... 

When mixtures of substances are investigated, e.g. in solid state reactions, the mixture should be completely homogeneous and of uniform particle size. Smaller particle size, i.e. higher ratio surface area/volume, are important for such types of reaction ... 

In a recent comprehensive study, Chhabra, Agarwal, and Sinha(27) have found that the most satisfactory characteristic linear dimension to use is the diameter of the sphere of equal volume and that the most relevant characteristic shape is the sphericity, (surface area of particle / surface area of sphere of equal volume). The limitation of this whole... 

The absorption fraction of a particle is related to the volume of the particle. Thus, the larger the volume of a particle, the more of the incident light is absorbed. In contrast, reflectance is related to the particles surface area, being in turn dependent on material porosity. The absorption/remission function relates to the fraction of absorbed light, the fraction of remitted (or back scattered) light, and the fraction of light transmitted by a representative layer... 

Reaction in the bulk. Reaction can occur in solution close to the surface or throughout the bulk of the liquid phase, depending on the speed of the reaction compared to diffusion. We shall see that whether the reaction occurs close to the surface or throughout the bulk has important implications for the kinetics, since in the former case, the reaction depends on the particle surface area, whereas in the latter it depends on the particle volume. 

The pore size of the membrane could also be controlled independently of the porosity by altering the size of the salt particles (Fig. 5a). Membranes with high surface area/volume ratios were produced and the ratio was dependent on both salt weight fraction and particle size (Fig. 5b). In addition, the crystallinity of PLLA membranes can be tailored to that desired for each application. These characteristics are all desirable properties of a scaffold for organ regeneration. The major disadvantage of this technique is that it can only be used to produce thin wafers or membranes (up to 2 mm in thickness). A three-dimensional scaffold cannot be directly constructed. This problem may be circumvented however, by membrane lamination. 

Hence, it is supplanted by the filler density (p) and its specific surface area (Q to address the shape factors. This can successfully represent the aspect ratio effects because changes in aspect ratio are reflected in the ratio of particle surface area to particle volume, i.e., density x surface area/gram. 

Removal of the fine sand has reduced the stopping power or breakthrough efficiency. Filter efficiency is also reduced. Filter efficiency has been directly related to the media particle surface area. The number of particles in a given volume of a dual-media filter has been reduced. The average size of the particles has also increased. As the filtered material is relatively loosely held in the coal layer, the materials are dislodged and will likely penetrate the sand layer and appear in the filter effluent if a flow change or applied solids surge occurs. 

Abstract. A multi-wavelength, multi-sensor Look-Up-Table (LUT) algorithm has been developed to retrieve information about stratospheric aerosols from satellite-based observations of particulate extinction. Specifically, the LUT algorithm combines extinction measurements from SAGE n with similar measurements from the CLAES instrument, and uses the composite spectra in month-latitude-altitude bins to retrieve values and uncertainties of particle effective radius, surface area, volume and size distribution width. 

Outer particle surface area per volume of column, cm /cm ... 

Figure 2.1 Expected values of <)> = the relative SVOC concentration in the particle phase/total air concentration as a function of the logarithm of the saturation vapor pressure, p0, in the region with particle surface areas per volume between clean air and urban air (Junge, 1977). The values are only a rough indication of p as a function of log(p0)-...

Several predictive approaches are available for estimating the fraction of POPs sorbed onto aerosols. The Junge-Pankow model assumes that gaseous POPs are adsorbed onto active sites on the aerosol. Key parameters in the model are particle surface area per unit volume of air (0), the liquid-phase vapor pressure of the compound ( P ) and a factor (c) which depends on the excess heat of desorption from the particle surface. 

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