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Microscopic models of soil using probability distributions
Published in Ryosuke Kitamura, Kazunari Sako, Unsaturated Soil Mechanics with Probability and Statistics, 2019
Ryosuke Kitamura, Kazunari Sako
There are several apparatuses used to examine the pore structure directly, such as the scanning electron microscope (SEM), the mercury intrusion porosimeter (MIP), and so on. However, in this subsection, a method to estimate the pore size distribution by means of grain size distribution function and the void ratio is proposed as the first approximate pore size distribution for the coarse-grained soil, because we aim to establish the versatile mechanical model for saturated–unsaturated coarse-grained soil based on only four fundamental soil properties, i.e., the grain size distribution function, the wet density of soil, the soil particle density and the pore water density. If the accurate pore structure can be easily obtained from simple experiments such as CT with image-processing in the future, the proposed approach to obtaining the pore size distribution in this subsection would be replaced by those direct approaches.
Gas Storage in Metal–Organic Frameworks
Published in T. Grant Glover, Bin Mu, Gas Adsorption in Metal-Organic Frameworks, 2018
Darren P. Broom, Jacob W. Burress
Materials properties associated with pore structure include surface area, pore size, pore size distribution, and total pore volume. Although each of these physical characteristics affect the gas storage properties of a material, considerable interplay exists between them, together with the surface chemistry. This interplay, however, for adsorption at different temperatures and pressures, is not yet fully understood. Gas adsorption also depends on the physical properties of the gas. Molecular size and electronic properties, such as the polarizability and the dipole and quadrupole moments, vary between different species. This variation leads to differing adsorption behavior in each case. Therefore, although there are general materials properties that apply to all applications, for example, high surface area, there are others, such as the pore size and geometry, that must be tailored to the application.
Alkali-activated portland cement-based blended cements
Published in Caijun Shi, Pavel V. Krivenko, Della Roy, Alkali-Activated Cements and Concretes, 2003
Caijun Shi, Pavel V. Krivenko, Della Roy
materials are lower in strength but their strength seems to increase with time. The pore structure evolution has been studied by mercury intrusion porosimetry. Results of pore size distribution measurement indicated that the alkali-activated systems develop a finer pore structure compared to neat cement pastes. In addition, the blends with high-calcium materials seem to develop the finest pore structure, possibly because they are more fully reacted. The 28-day mortar bar expansions using ASTM C 227 to test potential alkali-silica reaction clearly displayed that the alkali-activated aluminosilicate materials gave the lowest reaction rate with reactive silica.
Importance of appropriate segmentation in pore structure analysis of coral reef limestone from CT images
Published in Marine Georesources & Geotechnology, 2023
Hanbo Wan, Xin Huang, Junpeng Wang, Zixin Zhang
There is a general consensus that the physical and mechanical properties of porous media are closely related to their pore structure features. Some researchers have confirmed that the microstructure characteristics of porous rocks, such as the pore shape, could influence the overall mechanical properties of rocks, including the strength, stiffness, bulk modulus and Biot coefficient (Griffiths et al. 2017; Selvadurai and Suvorov 2020). The structural features could also influence the macroscale flow and transport phenomena inside, which thereby determines the permeability and seepage characteristics (Patmonoaji, Tsuji, and Suekane 2020; Ibrahim et al. 2019). Zhang, Ye, and Fu (2021) found that the aperture of the conduit plays a dominant role in the equivalent permeability coefficient (the average permeability of the whole rock volume) in porous rocks. Xie et al. (2022) concluded that under normal conditions, tight sandstone samples with lower connectedness, fewer intergranular dominant pores, and smaller grain sizes showed greater P-wave velocities and S-wave velocities, and vice versa.
A comparative study on nitridation mechanism and microstructural development of porous reaction bonded silicon nitride in the presence of CaO, MgO and Al2O3
Published in Journal of Asian Ceramic Societies, 2020
Raheleh Nikonam-Mofrad, Martin D. Pugh, Robin A. L. Drew
Although any solid that contains pores may be regarded as a porous or cellular material, the complexity and variety of pore structure are based on its morphology, shape, size and accessibility, which has led to several pore classes being described in literature [11]. Open-pore morphology and high porosity (typically >40 vol.%) are the important characteristics required for ceramic-metal composites, bone scaffold, separation membranes and filters as they provide high flow rate and channel interconnectivity [12–14]. In attempts to improve the porosity content and pore sizes above the ranges normally achieved in RBSN, that is to say 20–30 vol.% micro-porosity [10,15], a variety of approaches have been developed [1,4,16]. The sacrificial template technique is one of the most important methods yielding a high porosity content with a tailored pore structure governed by adjusting the vol.% and morphology of fugitive substances [17–19]. For instance, spherical pores with ≈53 vol.% porosity and rod-like pores with ≈42 vol.% porosity have been developed using benzoic acid balls [20] and organic whiskers [21], respectively. Similarly, the structure and size of cavities can be affected by the morphology of the RBSN grains constructing the skeletal part [22,23].
Pore structure classification and logging evaluation method for carbonate reservoirs: A case study from an oilfield in the Middle East
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Yi Han, Chong Zhang, Zhan-song Zhang, Hong-yue Zhang, Lie Chen
Pore structure is defined as the geometric shape, size and distribution of pores and throats and their connectivity in georeservoirs (Fu et al. 2015). For carbonate rocks, particle size, shape, sorting, pore type, and connectivity all have a direct impact on permeability. Simply using porosity and permeability cannot effectively classify reservoirs, and the conventional pore structure parameters obtained by the mercury injection are also difficult to characterize the pore structure of complex carbonate reservoirs (Smart et al. 2016). Therefore, it is necessary to construct new parameters that can accurately characterize the pore structure of the reservoir (Lai et al. 2016). The capillary pressure curve of mercury injection shows that the amount of mercury in the different pressure intervals represents the volume of the pore-throat system that is connected to each other with similar pore throat sizes. The amount of mercury when it reaches the maximum mercury saturation represents the total volume of all pore-throat systems in the sample (Zhao 1993).