Relative porosity

Intrinsic (natural, innate) resistance. In one form of intrinsic resistance, the fungal cell wall (see Chapter 2) is considered to present a barrier to exclude or, more likely, to reduce the penetration by biocide molecules. The evidence to date is sketchy but the available information tentatively links cell wall glucan, wall thickness and consequent relative porosity to the sensitivity of Saccharomyces cerevisiae to chlorhexidine. 

In order to estimate the probability of impact of the moistened part of a particle by surrounded particles in the fluidized bed, a simple model was developed [69], As an assumption that the fluidized bed is in an homogeneous condition, a certain portion of the relative porosity is assigned to each particle, and the shape of air covering the particle is taken to be a cube (Fig. 16.16). The entire bed consists of stacked cubes containing a particle at their center. The amount of air - and in consequence the distance between the particles - becomes larger for example, with the same fluidization mass flow the Archimedes number is decreased. The bed will then expand with a greater fluidization throughput and with a constant Archimedes number hence, the distance between the surrounded particles will increase. 

The functional progression dependency of the Sh-number on gas mass flow, expressed by the Re-number, is illustrated for experiment V-9 in Fig. 16.25. The curve has a maximum which is caused by the higher expansion (relative porosity) of the fluidized bed [66], In contrast to fixed beds, the energy input in fluidized beds is higher because of higher gas throughputs, and consequently the drying is faster. 

Relative porosity can then be determined by comparing the effective thickness of two regions, e.g., S3 and S2, using the following equation ... 

An equivalent surface area of 460 m g was determined from the monolayer volume, Vj. The value obtained for the dimensionless energetic constant, C=260, was characteristic of a microporous material. Although the BET surface area may not be a physically precise quantity due to the fact that the nitrogen molecule does not exhibit the same cross-sectional area in a microporous environment as on a flat surface, the BET value is useful for comparisons of relative porosities among a related class of adsorbents. For instance, smectite clays pillared by metal oxide aggregates typically exhibit BET surface areas in the range 150 - 400 m /g. Thus, the TSLS complex is among the more porous intercalated nanocomposites derived from smectite clays. 

In 1961 Heckel postulated a linear relationship between the logarithm of relative porosity (inverse density) of a powder and the applied pressure. The slope of... 

Repeated dissolution and recrystallization of these salts leads to the mechanical disruption of the masonry structure. Since the salts will concentrate in the more porous material, either the brick or the mortar will be more seriously affected, depending on their relative porosity. 

This definition, it should be noted, is somewhat in conflict with the definition of nanoscale objects, which typically have large relative porosities (> 0.4), and pore diameters between 1 and 100 nm. In order to classify porous materials according to the size of their pores the sorption analysis is one of the tools often used. This tool is based on the fact that pores of different sizes lead to totally different characteristics in sorption isotherms. The correlation between the vapor pressure and the pore size can be written as the Kelvin equation ... 

In this work, the sample that simulates the inside of an agglomerate is the only one that contains the primary elements, while samples of ascending scale contain only the sample of the immediately smaller scale and its corresponding porosity. We define the relative porosity as the volume fraction occupied by the empty spaces at that scale, ignoring that the pseudo-solid phase (or smaller scale) also contains some porosity. The volume fractions of the solid phase of each sample at different scales can be related mathematically by ... 

The input variables in the micro-structural reconstruction algorithm are (i) platinum load (y/t) (ii) Nafion load pn), (iii) weight percent of carbon-supported platinum iOpt), (iv) total porosity and relative porosity of n — 1 samples (v) domain and control volume dimensions at each scale and (vi) average size of representative elements at each scale. 

In this method, the pore size distribution is controlled indirectly by defining the relative porosity of the so-called meso-porous scale ( m,) as a percentage of total porosity ... 

These results are expected as Oo is directly proportional to the relative porosity of a sample with a larger scale, therefore, when its value decreases the volume of those pores with a larger size decreases. These results confirm that the pore size distribution of the CL was modified by controlling d>. Such distribution shows two peaks (at 0.05 xm and 0.3 xm), which are strongly influenced by the carbon particle size and the meso-pore size, and both parameters can be considered as input data. 

These statistical correlation functions were used as the reference systems in the annealing micro-structural reconstruction. Each sample was reconstructed and simulated five times with a different random series. In this reconstruction, relative porosities (O/) were determined by the statistical analysis of SEM micrographs and verified by the total experimental porosity obtained by mercury intrusion porosimetry. CL thickness (e) was also determined by SEM. CLs were studied by SEM at different resolutions. 

In geotechnical literature and standards, the terms relative density and density index are often used. In view of the contradicting definitions in various standards, these terms are replaced in this manual by relative void ratio i , and relative porosity R . The term relative density is only used in a general manner and does not refer to a specific definition. 

From an engineering perspective, the specification of the density of a material should be based on the future use of the fill. The relative void ratio or relative porosity (also called relative density) is often used to describe sand deposits. Correlations have been developed relating the relative density to the angle of internal friction, liquefaction potential, etc. 

Some manuals present guidelines for the relative void ratio or relative porosity. These values can be used as a guideline in the preliminary design of a hydraulic fill. It should be kept in mind that the relative density is an indirect way of defining the strength (see Section 8.3). The required relative density of non-cohesive soils in hydraulic fills depends on the type of utilisation, which is laid down in the functional requirements. 

Membrane selectivity from mixture measurement, =fijfk Membrane permselectivity from single gas measurement, = Relative porosity (0 < c )p < 1)... 

When the relative porosity effect is large, the penetration depth is small compared to the depth of the pores. De Levie [66] reported that for / > 3Xp the pore behaves as semi-infinite ("deep pore"), and for / < 0.2Xp the impedance behavior is similar to that of a flat electrode ("shallow pore"). For a simplified case where the concentration of electroactive species is high and the concentration gradient in pores is absent but there is a potential gradient, the details of the impedance representation for the porous electrode depend on the pore s... 

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