Porosity/pores

Pores, Porosity (in coatings) microscopic channels in coatings (metallic or non-metallic) which extend to the substrate. 

A rather limited range of mesopores in terms of size and volume were observed in the skeletons of polymer monoliths. The porosity of the polymer monolith seems to be lower than that of silica monolith. The total porosity of these monoliths is in the range of 0.61-0.73, whereas interstitial (through-pore) porosity and mesopore porosity are 0.28-0.70 and 0.03-0.24, respectively. In the case of poly(butyl methacrylate-co-ethylene dimethacrylate), the observed porosity is around 0.61-0.71, resulting in permeability 0.15-8.43 x 10 14 m2, whereas the observed porosity of silica monoliths prepared in a capillary is 0.86-0.96 and the permeability is 7-120 x 10 14 m2. Higher permeability will be advantageous for 2D applications, as mentioned later. 

As mentioned earlier, typical three-dimensional plots of s and s" versus frequency and temperature (see Fig. 14) suggest superimposing two processes (percolation and saddle-like) in the vicinity of the percolation. Therefore, in order to separate the long-time percolation process, the DCF was fitted as a sum of two functions. The KWW function (64) was used for fitting the percolation process and the product (25) of the power law and the stretched exponential function (as a more common representation of relaxation in time domain) was applied for the fitting of the additional short-time process. The values obtained for Dp of different porous glasses are presented in the Table I. The glasses studied differed in their preparation method, which affects the size of the pores, porosity and availability of second silica and ultra-porosity [153-156]. 

Intersection of grain boundaries Shrinkage of open pores Porosity decreases substantially Slow grain growth... 

Static methods Mercury intrusion Laplace (Washburn) Cylindrical 5 nm-15 pm Pore size distribution (including dead-end pores) Porosity Outgassed (dry) samples. Measurement of pore entrance. Destructive method. For small pore sizes damage of the porous structure may occur. Network percolation effects derived. 

The CO2 isotherms at 273 K for a various high-organic soils and humic acid particles (77,75) are Type I, characteristic of microporous solids (19). Furthermore, CO2 adsorption is two or more orders of magnitude greater than Nj adsorption at comparable relative pressures. Using a model that assumes liquid condensation of CO2 in the pores, porosities of up to several percent of total solid volume are indicated. Given that this porosity is not revealed in the N2 isotherms, it is reasonable to infer that the pores are small (< 1 nm in aperture), internal, and accessible only by diffusion through the solid state. 

Mercury intrusion test data show that before and after the consolidation the porosities of macropores (d > 10 pm) and the medium pores (5 pm < d < 10 pm) of the samples are very small the samples mainly contain the small pore (0.1 pm < d < 5 pm) the porosity of micropores (d < 0.1 pm) is greater than macropores and medium pores, but less than the small pores. Compared with the samples before consolidation, the small pores porosity has increased after consolidation and the quantity of macropores decreased. The reason is that soil particles slide or collapse due to the consolidation pressure. Therefore pores are compacted, and macropores reduce or even disappear. These conclusions are basically consistent with the SEM quantitative analysis. The samples mainly contain small pores before and after consolidation, pore size is primarily in the... 

Tomography by X-ray is a nondestructive technique for the characterization of objects. Like all the tomographies, it is a question of obtaining 3D information on the internal and/or external structure of the observed object. This technique thus makes it possible to observe and to inspect objects (search for defects, fractures, etc.) or to measure characteristic dimensions (thickness, size of pores, porosity, etc). This chapter covers only the tomography of absorption, which is the simplest technique. More sophisticated methods exist such as phase contrast tomt raphy [1, 2j. 

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