Volume Of Void Space Research Articles

Determination of Porosity in Fluidized-Bed Carburized P/M Compacts Using an Image Software Analysis

The aim of this research was to study the porosity in carburizing in fluidized-bed on sintered alloys produced by powder metallurgy route using an image analysis software and to compare the obtained results with the conventional method for porosity measurements. Porosity is a measure of the void fraction in a material. The total porosity is defined by the ratio of the volume of void space to the total bulk volume of the material, expressed as a percentage. Development of digital images and computer software lead to a new and suitable method to determine the porosity of powder metallurgy materials.

Mangrove roots model suggest an optimal porosity to prevent erosion

Mangrove swamps are extremely productive ecosystems providing many ecological services in coastal regions. The hydrodynamic interactions of mangrove roots and water flow have been proposed as a key element to mitigate erosion. Several studies reveal that precise prediction of the morphological evolution of coastal areas, in the face of global warming and the consequent sea-level rise, requires an understanding of interactions between root porosity (the fraction of the volume of void space over the total volume), water flows, and sediment transport. Water flows around the mangrove prop roots create a complex energetic process that mixes up sediments and generates a depositional region posterior to the roots. In this work, we investigated the boundary layer behind permeable arrays of cylinders (patch) that represent the mangrove roots to explore the impact of patch porosity on the onset of sediment transport. The flow measurements were performed in a vertical plane along the water depth downstream of the mangrove root models. A high-resolution Particle Image Velocimetry (PIV) was used in a flume to observe the impact of porosity on the mean flow, velocity derivatives, skin friction coefficient, and production of turbulent kinetic energy for Reynolds number of 2500 (based on patch diameter length-scale). Here, we proposed a predictive model for critical velocity for incipient motion that takes into account the mangrove roots porosity and the near-bed turbulence effect. It is found that the patch with the phi =47% porosity, has the maximum critical velocity over which the sediment transport initiates. We found the optimum porosity has the minimum sediment erosion and creates negative vorticity sources near the bed that increases the critical velocity. This signifies an optimum porosity for the onset of sediment transport consistent with the porosity of mangroves in nature. The phenomenological model is elucidated based on an analysis of the vorticity evolution equation for viscous incompressible flows. For the optimum porous patch, a sink of vorticity was formed which yielded to lower the near-bed turbulence and vorticity. The minimum velocity fluctuations were sufficient to initiate the boundary layer transition, however, the viscous dissipation dominated the turbulence production to obstruct the sediment transport. This work identified the pivotal role of mangrove root porosity in sediment transport in terms of velocity and its derivatives in wall-bounded flows. Our work also provides insight into the sediment transport and erosion processes that govern the evolution of the shapes of shorelines.

СОВЕРШЕНСТВОВАНИЕ КИСЛОТНЫХ ОБРАБОТОК В КОЛЛЕКТОРАХ, ХАРАКТЕРИЗУЮЩИХСЯ РАЗЛИЧНОЙ КАРБОНАТНОСТЬЮ (НА ПРИМЕРЕ НЕФТЯНЫХ МЕСТОРОЖДЕНИЙ ПЕРМСКОГО КРАЯ)

Актуальность работы обусловлена тем, что технологические параметры проведения кислотной обработки (время выдержки в пласте и объем состава) значительно влияют на результат геолого-технического мероприятия. По мнению многих специалистов, требует изучения вопрос о необходимости в технологическом процессе проведения обработки этапа выдержки кислоты в пласте и его продолжительности. Удельный объем кислотного состава, или его количество в расчете на метр обрабатываемой толщины пласта, определяется различными факторами, такими как состав горной породы, свойства призабойной зоны, желаемая глубина проникновения состава в пласт и др. Цель: оценка влияния технологических параметров проведения кислотных обработок на эффективность мероприятия на нефтяных месторождениях Пермского края, характеризующихся различной карбонатностью горных пород. Методом исследования является проведение лабораторных экспериментов с использованием прибора для определения карбонатности горных пород – карбонатомера КМ-04М, фильтрационных установок с моделированием пластовых условий УИК-5ВГ и AFS-300, а также установки микрофокусной рентгеноскопии. Результаты. На образцах керна месторождений Пермского края, отличающихся содержанием компонентов «кальцит-доломит-нерастворимый остаток» проведено моделирование кислотного воздействия с использованием двух кислотных составов с определением коэффициента изменения проницаемости и рентгенотомографическими исследованиями. Рентгенотомографические эксперименты на одном образце керна выполнены дважды: до и после моделирования кислотного воздействия. По данным фильтрационных и рентгенотомографических экспериментов подобраны условия эффективного применения кислотных составов на рассматриваемых месторождениях. Обобщение всех результатов позволило разработать рекомендации по оптимизации технологических параметров проведения обработок на рассматриваемых объектах. Применение рентгеновской томографии позволило выделить случаи, для которых в результате воздействия характерен прирост пустотности, но снижение проницаемости. Данный факт позволит проводить дальнейшие работы по совершенствованию рецептур составов и технологий их применения.

Controlled formation of magnetic yolk-shell structures with enhanced catalytic activity for removal of acetaminophen in a heterogeneous fenton-like system

Encapsulating magnetic nanoparticles in a silica shell is a promising approach in many research fields. We recently demonstrated that the magnetic yolk-shell structure of Fe3O4@SiO2, which consists of an inner magnetite core and outer silica shell separated by a hollow void space, and its modified counterparts can be used as an effective catalyst for removal of acetaminophen in a heterogeneous Fenton-like reaction. The present study develops this approach further in an effort to design an effective procedure for preparing an optimum yolk-shell structure capable of greater catalytic performance. We investigated the use of a controlled synthesis strategy to fabricate an Fe3O4@SiO2 yolk-shell structure under varying conditions. Our focus was a single-step process that examines the effects of Stöber solution temperature, tetraethyl orthosilicate (TEOS) and hexadecyltrimethylammonium bromide (CTAB) concentrations, ethanol and water volume ratio, incubation time, and temperature on Fe3O4@SiO2 textural morphologies. The catalytic performance of the prepared materials was evaluated through oxidative degradation of acetaminophen in a heterogeneous Fenton-like reaction. Field emission transmission electron microscopy observation showed that magnetic yolk-shell structures with appropriate diameter, shell thickness, and hollow void space could be generated through tight control of synthesis conditions. Particle size and hollow void space increased when TEOS concentration increased from 22.10 to 88.50 mM. Hollow void space also increased as incubation time increased from 24 h to 72 h or incubation temperature increased from 50 to 90 °C. However, a yolk-shell structure did not form at a TEOS concentration of 11.10 mM, an incubation time of 3 h, or with an inappropriate ratio of ethyl alcohol and deionized water. Catalytic activity for degradation of acetaminophen increased with increasing hollow void space and thinning silica shell. In addition, the selected appropriate materials exhibited effective catalytic performance over five cycles of regeneration. This study demonstrates the significance of controlling the formation of yolk-shell structures, which enabled us to produce Fe3O4@SiO2 yolk-shell structures of desired and predictable size, hollow void space volume, and shell thickness for higher catalytic performance in degradation of pharmaceuticals in heterogeneous Fenton-like systems.

Showcasing the application of synchrotron-based X-ray computed tomography in host-pathogen interactions: The role of wheat rachilla and rachis nodes in Type-II resistance to Fusarium graminearum.

Fusarium head blight, caused primarily by Fusarium graminearum (Fg), is one of the most devastating diseases of wheat. Host resistance in wheat is classified into five types (Type-I to Type-V), and a majority of moderately resistant genotypes carry Type-II resistance (resistance to pathogen spread in the rachis) alleles, mainly from the Chinese cultivar Sumai 3. Histopathological studies in the past failed to identify the key tissue in the spike conferring resistance to pathogen spread, and most of the studies used destructive techniques, potentially damaging the tissue(s) under study. In the present study, nondestructive synchrotron-based phase contrast X-ray imaging and computed tomography techniques were used to confirm the part of the wheat spike conferring Type-II resistance to Fg spread, thus showcasing the application of synchrotron-based techniques to image host-pathogen interactions. Seven wheat genotypes of moderate resistance to Fusarium head blight were studied for changes in the void space volume fraction and grayscale/voxel intensity following Fg inoculation. Cell-wall biopolymeric compounds were quantified using Fourier-transform midinfrared spectroscopy for all genotype-treatment combinations. The study revealed that the rachilla and rachis nodes together are structurally important in conferring Type-II resistance. The structural reinforcement was not necessarily observed from lignin deposition but rather from an unknown mechanism.

Use of High-Resolution X-Ray Micro-Computed Tomography for the Analysis of Internal Structural Changes in Maize Infected with Fusarium verticillioides

X-ray micro-computed tomography (X-ray micro-CT) is a non-destructive, three-dimensional (3D) imaging and analysis technique for the investigation of internal structure of a large variety of materials, including agricultural produce. As a relatively new method in the field of food science, X-ray micro-CT has been applied successfully to obtain micro-structural information of foods undergoing different physical and chemical changes. In this study, high-resolution X-ray micro-CT was used for non-destructive analysis of the internal structure of maize kernels infected with Fusarium verticillioides. The major anatomical features of the maize kernel were identified based on their differences in X-ray attenuation, i.e. the germ, scutellum, vitreous and floury endosperm. Fungal infection caused changes in the internal structure of the kernels over time, which included a decrease in total kernel volume and an increase in total volume of void space, with more voids observed in the germ and floury endosperm regions. No significant (P > 0.05) difference was observed between the control and the infected kernels; it was apparent that the changes observed in the infected kernels were not solely as a result of fungal growth. The grey level histograms of the control and infected kernels shifted to the lower grey value intensity range over time indicating an increase in void space within the kernels. In the 3D images, the increase in total volume of void space with fungal progression was clearer and the effect of fungal damage on the internal structure was evident.

Bird's nest-like nanographene shell encapsulated Si nanoparticles – Their structural and Li anode properties

Abstract Bird's nest-like nanographene shell (NGS) encapsulated Si@SiO 2 nanoparticles have been prepared by a simple chemical vapor deposition (CVD) method. The shell is comprised of a conformed coating with 4–10 layers of the nanographene, and nanographene spikes with the same thickness grown on the coating surface. The high crystallinity of the shell is demonstrated by XRD, HRTEM and Raman characterization. After SiO 2 has been removed, distinctive void space is created between Si core and nested NGS. Statistical estimation from TEM images of 50 Si@void@NGS particles shows that the volume of void space is about 2.82 times of that of Si nanoparticle, sufficient to accommodate volume change from Si to Li 15 Si 4 . Evaluation of Si@void@NGS for Li ion anode reveals a specific capacity of 2634 mAh g −1 at a current density of 0.2 A g −1 , and an excellent rate and cycling performance. The capacity decreases by 5.2%–2497 mAh g −1 after cycling at current densities of 0.5, 1, 2, 5 10, 20 A g −1 . The excellent performance can be attributed to high conductivity and high stability of the shell, which remains intact after repeated cycling.

Fibres and soils: A route towards modelling of root-soil systems

The addition of flexible fibres to granular, cohesionless soils, has a marked influence on the stress:strain and volumetric response. Experimental observations provide inspiration for the development of continuum models for the mechanical, pre-failure behaviour of these fibre/soil mixtures. Such generic models and the deduced mechanisms of response should be applicable to other combinations of soils and flexible fibres such as plant roots. Two features are particularly important: the distribution of the orientations of fibres (no method of preparation produces an isotropic distribution) and the allowance for the volume of void space not only occupied, but also influenced, by the presence of the fibres.A simple shear element is used as a quasi-one-dimensional demonstrator platform for the presentation of the continuum constitutive model. Such an element represents a familiar configuration in which phenomena, such as dilation and friction, can be directly observed. A basic constitutive model for sand is adapted to this simple shear element; the fibres are added as a separate component able to withstand tension but without flexural stiffness. As the soil-fibre mixture deforms, the straining of the soil generates stresses in favourably oriented fibres. The model is used to clarify some aspects of the response of the fibre-soil mixtures: the influence of fibres on the volumetric behaviour; the existence and nature of asymptotic states; and the stress–dilatancy relationship.

Impact of biofilm‐induced heterogeneities on solute transport in porous media

AbstractIn subsurface systems, biofilm may degrade organic or organometallic pollutants contributing to natural attenuation and soil bioremediation techniques. This increase of microbial activity leads to change the hydrodynamic properties of aquifers. The purpose of this work was to investigate the influence of biofilm‐induced heterogeneities on solute transport in porous media and more specifically on dispersivity. We pursued this goal by (i) monitoring both spatial concentration fields and solute breakthrough curves from conservative tracer experiments in a biofilm‐supporting porous medium, (ii) characterizing in situ the changes in biovolume and visualizing the dynamics of the biological material at the mesoscale. A series of experiments was carried out in a flow cell system (60 cm3) with a silica sand (Φ = 50–70 mesh) as solid carrier and Shewanella oneidensis MR‐1 as bacterial strain. Biofilm growth was monitored by image acquisition with a digital camera. The biofilm volume fraction was estimated through tracer experiments with the Blue Dextran macromolecule as in size‐exclusion chromatography, leading to a fair picture of the biocolonization within the flow cell. Biofilm growth was achieved in the whole flow cell in 29 days and up to 50% of void space volume was plugged. The influence of biofilm maturation on porous medium transport properties was evaluated from tracer experiments using Brilliant Blue FCF. An experimental correlation was found between effective (i.e., nonbiocolonized) porosity and biofilm‐affected dispersivity. Comparison with values given by the theoretical model of Taylor and Jaffé (1990b) yields a fair agreement.

Repeated inhalation exposure of rats to an anionic high molecular weight polymer aerosol: Application of prediction models to better understand pulmonary effects and modes of action

Opposed to the wealth of information available for kinetic lung overload-related effects of poorly-soluble, low-toxicity particles (PSP), only limited information is available on biodegradable high molecular weight (HMW) organic polymers (molecular weight >20,000Da). It is hypothesized that such types of polymers may exert a somewhat similar volume displacement-related mode of action in alveolar macrophages as PSP; however, with a differing biokinetics of the material retained in the lung. This polyurethane polymer was examined in single and 2-/13-week repeated exposure rat inhalation bioassays. The design of studies was adapted to that commonly applied for PSP. Rats were nose-only exposed for 6h/day for the respective study duration, followed by 1-, 2- and 4-week postexposure periods in the single, 2- and 13-week studies, respectively. While the findings in bronchoalveolar lavage (BAL) and histopathology were consistent with those typical of PSP, they appear to be superimposed by pulmonary phospholipidosis and a much faster reversibility of pulmonary inflammation. Kinetic modeling designed to estimate the accumulated lung burden of biopersistent PSP was also suitable to simulate the overload-dependent outcomes of this biodegradable polymer as long as the faster than normal elimination kinetics was observed and an additional ‘void space volume’ was added to adjust for the phagocytosed additional fraction of pulmonary phospholipids. The changes observed following repeated inhalation exposure appear to be consistent with a retention-related etiopathology (kinetic overload). In summary, this study did not reveal evidence of any polymer-specific pulmonary irritation or parenchymal injury. Taking all findings into account, 7mg polymer/m3 (exposure 6h/day, 5-days/week on 13 consecutive weeks) constitutes the point of departure for lower respiratory tract findings that represent a transitional state from effects attributable to an overload-dependent pulmonary inflammation and phospholipidosis. In regard to extrapulmonary toxicity, no effects were found up to the maximum concentration of 107mg/m3 examined.

Compressive and Tensile Strength of Artificially Cemented Dune Sand

Artificial cementation is a technique commonly used to improve the mechanical properties of soils for use in geotechnical engineering works, because it often provides economic and environmental advantages. In order to study the factors that influence the behavior of cemented dune sand from Natal, series of unconfined compression and splitting tension tests were performed. These tests showed that increasing the cement content and decreasing void ratio are effective ways to improve compressive strength. The same applies to tensile splitting strength. It was also established that both unconfined compressive and splitting tensile strengths can be related to a quotient between volume of void-space and cement content.

The theoretical plausibility of central pit crater formation via melt drainage

Central pit craters are seen in large craters on some icy satellites and on Mars. We investigate the hypothesis that central pits form when impact melt drains into fractures beneath the impact crater. For this process to occur, the volume of melt generated during the impact, the volume of void space in fractures beneath the impact crater, and the volume of melt able to drain before the fractures freeze shut all must exceed the volume of the observed central pits. We estimate the volume of melt generated using results from previous numerical modeling studies. The fracture volume is estimated using gravity anomalies over terrestrial craters. To estimate the amount of melt able to drain before freezing, we consider flow through plane parallel fractures. These calculations all suggest that enough liquid water could drain into fractured ice beneath a crater on Ganymede to form a central pit. On Earth and the Moon, silicate impact melt will freeze before a large volume is able to drain, so we do not expect to see central pits in impact craters in targets with no ice. In summary, we find our calculations are consistent with observed central pits in craters on Ganymede and the lack of central pits in craters on Earth and the Moon.

Two pole air gap electrospinning: Fabrication of highly aligned, three-dimensional scaffolds for nerve reconstruction

We describe the structural and functional properties of three-dimensional (3D) nerve guides fabricated from poly-ε-caprolactone (PCL) using the air gap electrospinning process. This process makes it possible to deposit nano-to-micron diameter fibers into linear bundles that are aligned in parallel with the long axis of a cylindrical construct. By varying starting electrospinning conditions it is possible to modulate scaffold material properties and void space volume. The architecture of these constructs provides thousands of potential channels to direct axon growth. In cell culture functional assays, scaffolds composed of individual PCL fibers ranging from 400 to 1500 nm supported the penetration and growth of axons from rat dorsal root ganglion. To test the efficacy of our guide design we reconstructed 10 mm lesions in the rodent sciatic nerve with scaffolds that had fibers 1 μm in average diameter and void volumes >90%. Seven weeks post implantation, microscopic examination of the regenerating tissue revealed dense, parallel arrays of myelinated and non-myelinated axons. Functional blood vessels were scattered throughout the implant. We speculate that end organ targeting might be improved in nerve injuries if axons can be directed to regenerate along specific tissue planes by a guide composed of 3D fiber arrays.

Comparative pulmonary response to inhaled nanostructures: considerations on test design and endpoints

Recently there has been increased concern and focus on the toxicity of engineered nanoparticulates (NPs). The tendency of NPs to aggregate and agglomerate in a concentration- and/or matrix-dependent manner often provides a continuum of particulates, ranging from nanosized to micrometer-sized. Agglomerated arrangements of closely packed nanoparticles increase the void-space volume and increase the composite volume of phagocytized particles. Consequently, much less particle mass is needed to exceed the volumetric overload limit for the inhibition of macrophage-mediated clearance. A unifying, most appropriate metric of NPs conferring pulmonary biopersistence and toxicity has not been demonstrated yet. Hence, it is timely to analyze and to consider to what extent current testing paradigms need to be modified in order to identify the unique hazards potentially associated with engineered nanostructured materials. Before embarking on novel testing paradigms, toxicological testing of NPs should be carried out according to already existing test guidelines to allow for a judicious utilization of the wealth of information that has already been generated for micrometer-sized particles. From the studies analyzed it is apparent that repeated inhalation exposure protocols of at least 1 mo are better suited than single high-dose instillation or inhalation studies to reveal the inhalation hazards of poorly soluble NPs. Along with all poorly soluble particles, due to their long retention half-times and associated biopersistence in the lung, even short-term inhalation studies may require postexposure periods of at least 3 mo to reveal NP-specific dispositional and toxicological characteristics.

Pendimethalin Movement Through Pine Bark Compared to Field Soil

Preemergence herbicides are commonly applied to nursery containers for control of annual weeds in the production of ornamental plants. Pine bark is a popular container growing medium because it is inexpensive, drains well, is easy to transport, and supports acceptable nursery crop growth. However, little is understood about leaching of herbicides through pine bark. The downward movement of these herbicides through container media may inhibit root growth in sensitive nursery crops and also reduce herbicidal efficacy. Four experiments were conducted at two different irrigation volumes to evaluate depth of pendimethalin movement in packed columns of pine bark and field soil. After 17.5 cm of water was applied over 7 d, pendimethalin moved downward into the 6 to 9-cm depth in 100% pine bark, whereas no movement was detected below the 0 to 3-cm depth in a Tetotum loam soil, as determined by a large crabgrass bioassay. Doubling the irrigation volume to 35 cm of water applied over 14 d did not significantly increase pendimethalin movement in pine bark or field soil. However, it did decrease pendimethalin persistence in the top 0 to 3-cm depth in pine bark. The pine bark had a higher cation exchange capacity than did the field soil. However, the physical characteristics of pine bark, a large volume of void space and low bulk density, resulted in higher hydraulic conductivity rates than in field soil. These factors may be the principal reasons that pendimethalin leached to a greater extent through pine bark than the field soil.

Ion exchange and luminescence of Eu 3+ in Nafion membranes

Dehydration of Nafion perfluorosulphonic membranes at 110 °C results in a significant reduction of their void space volume, the accessibility of sulphonic groups and the total exchange capacity towards Eu 3+ cations. Nevertheless, the ion exchange sorption of Eu 3+ takes place in accordance with stoichiometric ratio [–SO 3H]/[Eu 3+]=3. The membranes thermal pretreatment also affects noticeably the spectroscopic features of the fastened Eu 3+ ions, such as the relationship between the intensities of the hypersensitive 5D 0→ 7F 2 and magnetic dipolar 5D 0→ 7F 1 transitions, the excited state life time, as well as the luminescence quenching in the course of water adsorption.

Mass transfer correlations for rotating drum bioreactors

Evaporative cooling is extremely important for large-scale operation of rotating drum bioreactors (RDBs). Outlet water vapour concentrations were measured for a RDB containing wet wheat bran with the aim of determining the mass transfer coefficient for evaporation from the bran bed to the headspace. Mass transfer was expressed as the mass transfer coefficient times the area for transfer per unit volume of void space in the drum. Values of ka′ were determined under combinations of aeration superficial velocities ranging from 0.006 to 0.017 ms −1 and rotation rates ranging from 0 to 9 rpm. Mass transfer coefficients were evaluated using a variety of residence time distributions (RTDs) for flow in the gas phase including plug flow and well-mixed and a Central Jet RTD based on RTD studies. If plug flow is assumed, the degree of holdup at low effective Peclet ( Pe eff) numbers gives an apparent under-estimate of ka′ compared with empirical correlations. Values of ka′ calculated using the Central Jet RTD agree well with values of ka′ from literature correlations. There was a linear relationship between ka′ and effective Peclet number: ka′=2.32×10 −3 Pe eff.

灰重石‐ＭｎＣｌ２‐Ｈ２Ｏ系における交代作用のメカニズムに関する実験的研究

Experiments on metasomatism were carried out in the scheelite-aqueous MnCl2 solution system at 100, 125 and 150°C.As a result, the replacement texture of scheelite by huebnerite was confirmed in all experimental systems. Based on SEM observation of the section of the reacted samples, dissolution of scheelite and precipitation of huebnerite are considered to have occurred simultaneously. The replacement texture of scheelite by huebnerite progresses toward the inside of scheelite because there was no change in the form of the sample after the reaction. Since molar volume of huebnerite and scheelite are 41.88 and 47.05 cm3, respectively, large volume of void space is formed in the reaction layer. Activation energies of the dissolution reaction of scheelite were estimated to be 56.4 kJ/mol in 0.01 mol/l aqueous MnCl2 solution, 70.2 kJ/mol in 0.10 mol/l aqueous MnCl2 solution and 62.2 kJ/mol in 1.00 mol/l aqueous MnCl2 solution. SEM observation, observation in the polished section and estimated activation energies suggest that the dissolution reaction of scheelite is a rate-limiting factor.

PORE SIZE DISTRIBUTION AND STRUCTURE OF A COOKED BEEF PRODUCT AS AFFECTED BY VACUUM COOLING

ABSTRACTTrue density, apparent density, and pore size distribution were measured for a vacuum cooled cooked beef product using helium pycnometry and mercury porosimetry. Vacuum cooled samples resulted in the development of high porosity and lower density in comparison to more conventional cooling methods. Pore size distribution for vacuum cooled samples revealed the presence of random pore sizes with no distinct pore size but rather a pore size range of 10 μm to 0.02 μm. It was determined that the vast majority of porosity in vacuum cooled samples was composed of void space volume as distinct to regular pores. Analysis of estimated diffusion coefficients revealed that the efficiency of vacuum cooling is dependent on the development of porosity within the samples during cooling which leads to more efficient cooling times and higher diffusion rates in samples with higher porosity and larger pore size distributions.

Pore and throat size distributions measured from synchrotron X‐ray tomographic images of Fontainebleau sandstones

The three‐dimensional geometry and connectivity of pore space controls the hydraulic transport behavior of crustal rocks. We report on direct measurement of flow‐relevant geometrical properties of the void space in a suite of four samples of Fontainebleau sandstone ranging from 7.5 to 22% porosity. The measurements are obtained from computer analysis of three‐dimensional, synchrotron X‐ray computed microtomographic images. We present measured distributions of coordination number, channel length, throat size, and pore volume and of correlations between throat size/pore volume and nearest‐neighbor pore volume/pore volume determined for these samples. In order to deal with the ambiguity of where a nodal pore ends and a channel begins, we apportion the void space volume solely among nodal pores, with the channel throat surfaces providing the nodal pore delineations. Pore channels thus have length but no associated volume; channel length is defined by nodal pore center to nodal pore center distance. For a sample of given porosity our measurements show that the pore coordination number and throat area are exponentially distributed, whereas the channel length and nodal pore volume follow gamma and lognormal distributions, respectively. Our data indicate an overall increase in coordination number and shortening of pore channel length with increasing porosity. The average coordination number ranges from 3.4 to 3.8; the average channel length ranges from 200 to 130 μm. Average throat area increases from 1600 to 2200 μm2 with increasing porosity, while average pore volume remains essentially unchanged at around 0.0004 mm3.