Determination Of Total Porosity Research Articles

Measurement System Analysis of Densometry Technique for the Determination of Porosity and Thickness of Porous Fuel Cell Media

Porosity is one of the critical parameters governing mass transport of reagents and products in the heterogenous architecture of a fuel cell electrode. Techniques for the measurement thereof are required that are rapid, cost-effective, and simple, and yet capable of the highest levels of accuracy, precision, and stability. This body of work presents a comprehensive account of the measurement system analysis (MSA) of the densometer technique for the ex situ determination of total porosity and mean thickness of thin film porous materials by way of hydrostatic principles. The MSA involved a four phased approach which systematically tested several process assumptions before performing gage precision and accuracy studies and, finally, benchmarking of the system against several conventional industry techniques. Results confirmed statistically that the densometry technique, in conjunction with a standardized measurement procedure, can be used for the precise and accurate measurement of porosity as well as thickness across a representative range for porous materials deployed in fuel cells and similar technologies.

Effects of microencapsulated phase change materials on chloride ion transport properties of geopolymers incorporating slag and, metakaolin, and cement-based mortars

The addition of microencapsulated phase change materials (MPCMs) to geopolymers is a technological alternative for meeting the thermal comfort and energy efficiency requirements of buildings. However, current research is limited to the effects of MPCM addition on mechanical and thermal performances of geopolymers. New MPCM applications, therefore, require additional research on durability indicators (chloride diffusivity, porosity, absorption, etc.). The objective of this research is to examine the effects of MPCM addition on sodium chloride ion transport properties of geopolymer mortars based on a combination of blast furnace slag and metakaolin, and Portland cement based mortars. Twelve different mortars (three cement-based and nine geopolymer-based) are studied by varying the MPCM content (0%, 5% and 10%, respectively) within two types of mortar: a geopolymer mortar (GPM) and a cement mortar (CM). With this aim in view, a series of characterizations are conducted, including determination of total porosity by water saturation, analysis of pore structure distribution by mercury intrusion porosimetry (MIP), measurement of electrical resistivity, capillary water uptake, stationary-state migration coefficient “Dss” and non-stationary-state migration coefficient “Dnss”, and determination of chloride ion binding capacity. The results show that MPCM addition increases total porosity, which in turn increases capillary water absorption and decreases GPM and CM electrical resistivity. Conversely, MPCM addition also reduces critical diameter and pore connectivity, due of the agglomeration effect. MPCMs also increase chloride ion binding capacity. Both effects results in decreased stationary state migration coefficient. Finally, the study shows that the chemical reaction of GPM with chloride ions delays chloride penetration in stationary state conditions. However, the same is not true for the non-stationary state method. This demonstrates the technical limitations of this method for the characterization of GPM in comparison to CM.

Reservoir Characteristics and Influencing Factors of Organic-Rich Siliceous Shale of the Upper Permian Dalong Formation in Western Hubei

To elucidate the reservoir characteristics of organic-rich siliceous shale of the Upper Permian Dalong Formation in western Hubei, this study focused on the drilling cores of Well ED-2. Various techniques, including a mineral composition analysis, an organic carbon content analysis, a vitrinite reflectance measurement, a total porosity determination, field emission scanning electron microscopy (FE-SEM), and low-pressure CO2 and N2 physical adsorption tests, were employed to analyze the mineralogy, organic geochemistry, total porosity, and pore structure characteristics. Additionally, the factors influencing the reservoir performance of the Dalong Formation shale were investigated. The results indicated that the Dalong Formation’s shale was characterized as an organic-rich siliceous shale. Organic matter was mainly of sapropelic type, with a relatively high thermal evolution degree and Ro ranging from 2.59% to 2.76%. The total porosity of the Dalong Formation’s siliceous shale was low, indicating poor reservoir properties. Organic matter pores were highly developed, mainly the ones formed after the hydrocarbon generation of solid asphalt. Micropores and mesopores were the dominant pore types in the shale, with macropores being significantly less abundant. The study further revealed that the pore volume and specific surface area exhibited a significantly positive correlation with total organic carbon (TOC) content and clay minerals, while demonstrating a weak negative correlation with quartz content. The comprehensive analysis revealed that there were two factors contributing to the poor physical properties of organic-rich siliceous shale in the Dalong Formation. Firstly, in siliceous shale with a high quartz content, the siliceous component was partly derived from the siliceous cementation of hydrothermal fluids. This process led to the formation of secondary quartz that filled intergranular pores, resulting in a decrease in macropore volume, total porosity, and a weak negative correlation with quartz content. Secondly, in siliceous shale with a relatively high clay mineral content, the organic matter was subjected to stronger compaction due to the relatively low content of brittle minerals. This compaction caused the destruction of most macropores, leaving behind primarily micropores and mesopores. Consequently, the average pore size decreased, leading to poor physical properties.

Gas diffusion characteristics of agricultural soils from South Greenland

AbstractThe Arctic is warming at twice the global average, which may impact agricultural production in Greenland. Therefore knowledge of the functional properties of Greenlandic soil resources is necessary. The relative soil gas diffusivity [the soil gas diffusion coefficient (Dp)–free‐air diffusion coefficient (Do) ratio] is the chief parameter controlling gas transport in soils. Predictions of Dp/Do are needed to estimate root zone aeration and terrestrial greenhouse gas fluxes. We used existing models to analyze the Dp/Do of soils from Greenlandic fields and a pore connectivity index (Cip) to infer their degree of structural development and identify the main parameters controlling Dp/Do. In total, 201 × 3 intact 100‐cm3 soil samples were sampled across six fields with clay and organic C contents of 0.016 to 0.089 and 0.016 to 0.105 kg kg−1, respectively. The Dp/Do was measured with the one‐chamber nonsteady‐state method at soil water potentials between –10 and –1,000 cm H2O. Accurate determination of total porosity (Φ) was ensured by calibrating a particle density model on 129 samples. The soils exhibited a less developed structure and highly tortuous pore networks, resulting in low Dp/Do as a function of air‐filled porosity (ε). Density‐corrected models with air saturation (ε/Φ) reduced the RMSE. Furthermore, Cip at –1,000 cm H2O soil water potential increased linearly with dry bulk density (ρb), suggesting that ρb is a key controller of Dp/Do, which is important for planning cultivation practices for Southern Greenlandic soils. Lastly, we found that an air saturation >35% is required for adequate soil aeration.

Reservoir Properties of Low-Permeable Carbonate Rocks: Experimental Features

This paper presents an integrated petrophysical characterization of a representative set of complex carbonate reservoir rock samples with a porosity of less than 3% and permeability of less than 1 mD. Laboratory methods used in this study included both bulk measurements and multiscale void space characterization. Bulk techniques included gas volumetric nuclear magnetic resonance (NMR), liquid saturation (LS), porosity, pressure-pulse decay (PDP), and pseudo-steady-state permeability (PSS). Imaging consisted of thin-section petrography, computed X-ray macro- and microtomography, and scanning electron microscopy (SEM). Mercury injection capillary pressure (MICP) porosimetry was a proxy technique between bulk measurements and imaging. The target set of rock samples included whole cores, core plugs, mini cores, rock chips, and crushed rock. The research yielded several findings for the target rock samples. NMR was the most appropriate technique for total porosity determination. MICP porosity matched both NMR and imaging results and highlighted the different effects of solvent extraction on throat size distribution. PDP core-plug gas permeability measurements were consistent but overestimated in comparison to PSS results, with the difference reaching two orders of magnitude. SEM proved to be the only feasible method for void-scale imaging with a spatial resolution up to 5 nm. The results confirmed the presence of natural voids of two major types. The first type was organic matter (OM)-hosted pores, with dimensions of less than 500 nm. The second type was sporadic voids in the mineral matrix (biogenic clasts), rarely larger than 250 nm. Comparisons between whole-core and core-plug reservoir properties showed substantial differences in both porosity (by a factor of 2) and permeability (up to 4 orders of magnitude) caused by spatial heterogeneity and scaling.

Estimating porosity and hydraulic conductivity for hydrogeology on the basis of reservoir and elastic petrophysical parameters

The aim of paper was to show how petrophysical parameters measured in laboratory or as well logging outcomes can be used to determine hydrogeological quantity - porosity and combine it with hydraulic conductivity. Bulk density and acoustic waves velocity were applied to calculate porosity besides of laboratory mass measurements applied as standard in hydrogeology. Anisotropy question was touched because petrophysical parameters measured in two perpendicular directions revealed different results.Upper Jurassic carbonate samples from two regions of South Poland were used in laboratory measurements of elastic and reservoir properties to determine open/effective-interconnected and total porosity, bulk density and hydraulic conductivity. Petrophysical measurements of bulk density and elastic P-wave and S-wave velocities were used for total porosity determination. The obtained results were also basis for the dynamic elastic moduli calculations. Laboratory measurements and analyses were done separately for the samples cut horizontally and vertically to bedding to underline possibility of anisotropy recognition. The main goal of investigations was to determine porosity from various methods and show that well logging results can be used rather than laboratory results. Hydrogeological parameters determination from well logs might be crucial in deep aquifers prospection.

Optimal conditions of porous ceramic membrane synthesis based on alkali activated blast furnace slag using Taguchi method

Abstract The main purpose of this research is to synthesize porous ceramic membrane based on alkali-activated blast furnace slag and achieve optimal synthesis conditions for removing over 90% petroleum compounds and flux in the range of microfiltration (MF) and ultrafiltration (UF). The method applied for membrane synthesis is simple, environmentally friendly, and economical. The blast furnace slag as the main starting material was used to fabricate these free sintering and self-supported ceramic membranes. The L 9 orthogonal array of the Taguchi method was employed to determine the optimum conditions of three controlling factors, i.e. hydraulic pressing pressure, alkali-activated blast furnace slag drying time, and pressing time in three levels. Morphology and filtration performance of the synthesized membranes were characterized via SEM images using Image-j software, total porosity determination, and pore size study using bubble point method. Cross-flow filtration of 75 ppm gas oil in water emulsion was performed and COD analysis of permeate was then monitored. Distribution of synthesis parameters and their influences on the membrane fabrication process were investigated using analysis of variance (ANOVA). According to the results, drying time and hydraulic pressing pressure were known as the most effective parameters on COD and permeation flux. Two optimal membranes for COD removal and permeation flux were identified in hydraulic pressing pressure, drying time and pressing time of (400 bar, 6 h, 5 min) and (225 bar, 8 h, 30 min), respectively. COD optimal UF membrane with an average pore size of 0.07 µm and 100% removal of gas oil and permeation flux optimal MF membrane with an average pore size of 0.66 µm and pure water permeation flux of 1960 kg/m 2 h were introduced.

3D Analysis of Porosity in a Ceramic Coating Using X-ray Microscopy

Suspension plasma spraying (SPS) is a new, innovative plasma spray technique using a feedstock consisting of fine powder particles suspended in a liquid. Using SPS, ceramic coatings with columnar microstructures have been produced which are used as topcoats in thermal barrier coatings. The microstructure contains a wide pore size range consisting of inter-columnar spacings, micro-pores and nano-pores. Hence, determination of total porosity and pore size distribution is a challenge. Here, x-ray microscopy (XRM) has been applied for describing the complex pore space of the coatings because of its capability to image the (local) porosity within the coating in 3D at a resolution down to 50 nm. The possibility to quantitatively segment the analyzed volume allows analysis of both open and closed porosity. For an yttria-stabilized zirconia coating with feathery microstructure, both open and closed porosity were determined and it could be revealed that 11% of the pore volumes (1.4% of the total volume) are closed pores. The analyzed volume was reconstructed to illustrate the distribution of open and closed pores in 3D. Moreover, pore widths and pore volumes were determined. The results on the complex pore space obtained by XRM are discussed in connection with other porosimetry techniques.

Influence of Chemical Composition and Production Process Parameters on the Structure and Properties of Silver Based Composites With ZnO / Ocena Wpływu Składu Chemicznego Oraz Parametrów Wytwarzania Na Strukturę I Właściwości Kompozytów Na Osnowie Srebra Z Udziałem ZnO

The paper shows results of the study into influence of chemical composition and consolidation process conditions on changes of physical and electrical properties of silver-based composites used in production of electric contacts. The investigations addressed influence of content of zinc oxide (ZnO) and modifying additions in a form of silver tungstate (Ag2WO4) and silver molybdate (Ag2MoO4) on changes in density, porosity and electrical conductivity. Density of the produced compacts was established by geometric method. The results of density measurements were used in determination of total porosity of sinters. Also arc erosion was examined to determine applicability of the produced composites for production of electric contacts. The erosion was measured as mass loss of individual materials after specific number of connections. The studies were conducted at current intensity of 10 A and voltage of 500V. The scope of the studies covered also evaluation of kinetics of sintering of the examined composites and determination of the mechanisms of mass transport in the process. Studies into kinetics of sintering were conducted in the air atmosphere at constant temperature of 900°C. Production of the examined composite materials consisted of mechanical synthesis of powders of silver, zinc oxide and silver tungstate and molybdate, and then their consolidation by two-sided pressing and subsequent sintering. In cold pressing various pressures were applied 200, 300 and 400 MPa. Sintering was performed with a partial participation of liquid phase in temperature of 900°C. Also additional two-sided pressing was applied under pressure of 500 MPa and stress-relieving recrystallization annealing was performed as the final operation.

Application of 19F NMR relaxometry to the determination of porosity and pore size distribution in hydrated cements and other porous materials

The potential to determine the porosity of cements and other porous materials by employing 19F NMR relaxometry was explored for samples of hydrated Portland cement, white cement and calcium aluminate, filled with Freon 11. The dependence of 19F signal amplitudes on the content of Freon in samples with completely filled pores was linear with a small (< 6%) intercept thus allowing a direct determination of total porosity. Additionally it was found that magnetic susceptibility (hence the content of paramagnetic compounds) of the solid can be evaluated from 19F NMR spectra of samples containing exterior liquid. Information concerning pore size distribution can be obtained from the analysis of multiexponential relaxation of 19F nuclei in samples with completely filled pores. Mathematical models employing sets of distributions of relaxation rates have been developed for this purpose. Distributions were assumed to be of a (fixed) square/triangular type allowing for the calculation of moments of any order from the estimated initial value, width of distribution and asymmetry factor. Longitudinal and transverse relaxation were characterised by either single or several continuous distributions of relaxation rates. One of the relaxating phases (assigned to fluid occupying throats connecting the pores) was found to selectively disappear when Freon was evaporated from samples. Another approach is to analyse the dependencies of means and variances of relaxation rates on Freon content. This has been done by employing the two-site relaxation model with a permanent adsorption layer and pore-dependent relaxation enhancement. Simultaneous fitting of dependencies of means and variances of relaxation rates on Freon content yields parameters of pore size distribution and of the dependence of relaxation enhancement on the pore radius. Analysis of experimental data shows agreement between these two approaches.

Use of X-ray tomography to study the porosity and morphology of granules

X-ray computed tomography (XRCT) is a technique that uses X-ray images to reconstruct the internal microstructure of objects. Known as a CAT scan in medicine, it has found wide application for whole-body and partial-body imaging of hard tissues (e.g., bone). A modern tabletop XRCT system with a resolution of about 4 μm was used to characterize some pharmaceutical granules. Total porosity, pore size distribution, and geometric structure of pores in granules produced using different conditions and materials were studied. The results were compared to data obtained from mercury porosimetry. It was found that while XRCT is less precise in the determination of total porosity in comparison to mercury porosimetry, it provides detailed morphological information such as pore shape, spatial distribution, and connectivity. The method is nondestructive and accurate down to the resolution of the instrument.Tomographic images show that the pore network of individual granules comprises relatively large cavities connected by narrow pore necks. The major structural difference between granules produced at different conditions of compaction and shear is a reduction in the pore neck diameter; the cavity size is relatively insensitive to these conditions. Comparison of pore size distributions determined from tomographic images and mercury porosimetry indicates that mercury intrusion measures the pore neck size distribution, while tomography measures the true size distribution of pores ca. 4 μm or larger (the instrument resolution).

A New Multiband Generation of NMR Logging Tools

Summary This paper describes the hardware and operation of a new generation of nuclear magnetic resonance (NMR) logging tools. In the past, NMR required the logging engineer to consider the T1 relaxation times of the reservoir fluids likely to be encountered. Actual, or simply assumed, long T1's translated into slow logging speeds. The new tool generation overcomes this limitation. The key feature is that nine sensitive volumes are polarized in parallel and are read out in rapid sequence. A new sonde design speeds up the polarization process by a factor of 2. Each volume contributes equally to the result and can support identical measurements for rapid stacking and fast logging, and each can be used for individual, simultaneous measurements. Laboratory data and field-test results are presented to demonstrate both the relative simplicity of operation and the improvement in data quality. Logging speeds typically can be upgraded by a factor of 4, while data for total porosity determination and fluid typing are acquired in a single logging pass.

Image analysis techniques for characterization of pore structure of cement-based materials

This paper explores several image analysis techniques that provide insight into the nature of pore structure as observed in backscattered electron images of polished sections. Image analysis techniques used in this study include sizing, two-point correlation, and fractal analyses. The spatial parameters computed by these techniques have potential for relating microstructure to material properties. Specimens include plain cement paste, pastes with silica fume, and mortars. Tests include determination of total porosity, mercury intrusion porosimetry (MIP), compression and flexural testing. The two-parameter fracture model is used to characterize fracture properties. Pore size distribution from MIP is compared to pore size distribution derived from BSE images.

Formulae for total porosity evaluation on sodium chloride ice and urea-doped ice

The method of Cox and Weeks (1983) for the determination of the total porosity in sea ice samples from given salinity, temperature and density is applicable to ice frozen from other similar aqueous solutions as well. The phase relations of the systems sodium chloride-water and urea-water are analysed in this respect. The coefficients for total porosity determination on sodium chloride and urea doped ice are given for subeutectic dopant concentrations and supereutectic temperatures.

Physical Characteristics of Thatch as a Turfgrass Growing Medium1

AbstractWhere a substantial thatch layer exists, new roots and stem growth from plant crowns occurs, at least initially, within the thatch. In some turfs, very little rooting may occur in the soil underlying the thatch. Therefore, under these conditions it appears that the thatch serves a greater role as a plant‐holding matrix and a growth medium while the soil's role decreases. The objective of this study was to determine the bulk density, total porosity, moisture characteristics, and organic matter contents of thatch and surface soils of thatched and thatch‐free Kentucky bluegrass (Poa pratensis L.) sites.The evaluation methods included: 1) the core method for measuring bulk density; 2) air pycnometric determination of total porosity; 3) a modified pressure plate procedure utilizing Tempe cells for determining moisture extraction curves; and 4) organic matter content on the basis of weight loss upon ignition. Bulk density of thatch was significantly lower than soil, but varied between thatch samples depending on the amount of soil within the thatch. Total porosity of thatch samples was not significantly different, but was greater than soil porosity. Moisture retention of thatch at low water potentials was less than the surface soil from thatch‐free sites, indicating that most of these pores are macro‐size pores. This study suggests that cultural practices, such as irrigation, may need to be modified to sustain aesthetic turf where thatch is a predominant component of the edaphic environment.

Porosity-strength considerations for cellular concrete

The inclusion of air voids in the determination of total porosity for neat cellular concretes permits the determination of a single strength-porosity relation for a given cement. This relation can be expressed in terms of water-cement ratio and density, thus providing a simple tool for the design of these concretes.

Rückdifferenzierung als Voraussetzung ontogenetischer Entwicklung.

The main purpose of this research is to synthesize porous ceramic membrane based on alkali-activated blast furnace slag and achieve optimal synthesis conditions for removing over 90% petroleum compounds and flux in the range of microfiltration (MF) and ultrafiltration (UF). The method applied for membrane synthesis is simple, environmentally friendly, and economical. The blast furnace slag as the main starting material was used to fabricate these free sintering and self-supported ceramic membranes. The L9 orthogonal array of the Taguchi method was employed to determine the optimum conditions of three controlling factors, i.e. hydraulic pressing pressure, alkali-activated blast furnace slag drying time, and pressing time in three levels. Morphology and filtration performance of the synthesized membranes were characterized via SEM images using Image-j software, total porosity determination, and pore size study using bubble point method. Cross-flow filtration of 75 ppm gas oil in water emulsion was performed and COD analysis of permeate was then monitored. Distribution of synthesis parameters and their influences on the membrane fabrication process were investigated using analysis of variance (ANOVA). According to the results, drying time and hydraulic pressing pressure were known as the most effective parameters on COD and permeation flux. Two optimal membranes for COD removal and permeation flux were identified in hydraulic pressing pressure, drying time and pressing time of (400 bar, 6 h, 5 min) and (225 bar, 8 h, 30 min), respectively. COD optimal UF membrane with an average pore size of 0.07 µm and 100% removal of gas oil and permeation flux optimal MF membrane with an average pore size of 0.66 µm and pure water permeation flux of 1960 kg/m2 h were introduced.