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The article presents analytical and experimental studies to determine the density of the wood cell walls and other porous materials. From the literature, four main methods have been identified for determining the density of the cell walls of wood and porous materials. Of these, there are three direct methods: suspensions, mercury porosimetry and pycnometry, and one indirect - optical (planimetric). Helium gas pycnometry method is the most common of these ones. Based on the results of the critical analysis, a method for measuring the volume and determining the density of the cell walls of wood and porous materials in the atmosphere of atmospheric air was proposed. The method was theoretically substantiated and does not contradict the basic postulates and laws of thermodynamics. The functional suitability of the proposed method, as well as a high degree of reliability of the results obtained, has been determined experimentally. Volumes and densities of the cell walls of various wood species and other porous materials were measured under various modes of the system functioning using the developed experimental installation. The lowest density values were obtained at an overpressure of +70 kPa, the highest were seen at a vacuum of -90 kPa. The deviations in the results between the highest and lowest density values were, respectively: spruce – 7.02%, aspen – 4.12%, thermally modified (TM) linden – 2.95%, pine rot – 4.93%, shelf fungus – 5.12%, pine bark – 5.27%, birch charcoal – 14.6%.

Aluminum (Al) and Al–4.5Cu wt% open-cell foams were produced by the replication casting technique in two different pore sizes, avoiding subsequent heat treatments. All produced samples were physically characterized by means of He pycnometry. Microstructural and chemical analyses were carried out using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and image processing techniques. Uniaxial compression tests were conducted, with the aim of generate the stress–strain curves of the Al and Al–4.5Cu wt% foams. It was found that plastic collapse and plateau stresses increased from ~ 3 and ~ 12 MPa to ~ 10 and ~ 30 MPa, while the energy absorption capacity of the Al–4.5Cu wt% foams was almost trebled regard the pure Al foams. These outcomes were attributed to the formed microstructure, constituted by dendritic arrangement of α-Al (~ 57 HV) and θ-Al2Cu (~ 326 HV). Thus, this work gives way to produce mechanically enhanced open-cell Al foams derived from the Cu addition.

This study used a range of integrated and complementary experiments to examine pore-structure, fluid-shale wetting characteristics, sample size-dependent porosity towards different fluids, and imbibition behavior, as well as the relationships between these properties and the mineralogy of Silurian mudstones in the Central Taurides of Turkey. Working with different sample-sizes, the experiments consisted of helium pycnometry, low-pressure nitrogen physisorption isotherm, mercury intrusion porosimetry, fluid immersion porosimetry, liquid displacement, fluid droplet wettability and contact angle measurements, and spontaneous imbibition of fluids; four fluids with different hydrophilicity were used to assess the characteristics of fluid-shale interaction and its influence on pore-structure. Results show that studied mudstones can be grouped into three rock types: siliceous, carbonate-dominated, and mixed mudstones. Siliceous and mixed mudstones have higher porosities, pore-throat diameters, surface areas and tortuosities than the carbonate-dominated mudstones, regardless of sample sizes and fluids used. With low permeabilities and medium pore-throat sizes for the siliceous and mixed mudstones, the wettability and imbibition results show that these mudstones are both oil-wet and moderately-to-high water-wet. In contrast, the carbonate-dominated mudstones exhibit oil-wet characteristics. These results indicate that studied siliceous and mixed mudstones in the Central Taurides seem to have appropriate petrophysical properties in the context of reservoir quality.

In order to provide technical support for the shale gas exploration and development in the Lower Silurian Longmaxi Formation of the Sichuan Basin, this paper takes the Longmaxi Formation in the Changning and Fuling Shale Gas Fields as the research object to quantitatively characterize the development characteristics of natural fractures in the Longmaxi Formation shale by means of helium pycnometry, X-ray diffraction (XRD), true density testing and other methods, with the aid of the modified petrophysical model. Then, the development types and genetic mechanisms of natural fractures and their influences on shale gas development are discussed. The following research results are obtained. First, the modified petrophysical model can accurately describe the pore system in the Changning shale with a fitting rate of 0.74. Second, the development of natural fractures in shale is different in various regions. The natural fractures in the Changning Shale Gas Field, controlled by basement thrust faults, decollement layers and internal folds, are locally developed and filled with calcareous, and the average fracture porosity is 0.15%. In the Fuling Shale Gas Field, however, natural fractures, mainly controlled by reverse faults and slippage effect, are commonly more developed and unfilled or semi-filled with siliceous, and the average fracture porosity is 1.30%. Third, under the formation conditions, the opening of natural fractures is different. The natural fractures in the Changning Shale Gas Field are basically closed with weaker flowing ability, while those in the Fuling Shale Gas Field are relatively open with stronger flowing ability. Fourth, the occurrence mode of shale gas is influenced by natural fractures, and it is internally dominated by free gas. The initial gas production of shale gas wells is higher. In conclusion, (1) the regression coefficient is introduced to calculate the actual total organic matter content, which promotes the modified petrophysical model to describe matrix pores and fracture pores more accurately; (2) the development of natural fractures in the shale producing pay of the Sichuan Basin is relatively beneficial to shale gas enrichment and exploitation, but the flowing ability of the natural fractures will be weakened under the original formation conditions.

Based on previous observations that a pressurized water treatment (PWT) prevented cracking of sol–gel microspheres, we investigated the effects of a PWT on microsphere crystallinity, density, and specific surface area (SSA). Results were used to determine how a PWT alters the properties of microspheres upon drying and heating. Microspheres with diameters near 100–200 µm were prepared with and without a PWT and measured using x-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption (BET), and pycnometry. Properties of air-dried microspheres processed with and without a PWT are compared. In addition, the properties of microspheres processed using a PWT are reported after heating to 150, 450, 750, 1050, and 1350 °C. XRD measurements indicate that the PWT step improves the crystallinity of air-dried microspheres. XRD data were also used to calculate crystallite size, which increases with higher heat-treatment temperatures. TEM images support crystallite size calculations from XRD data and provide an indication of the range of crystallite sizes, particularly for samples processed at higher temperatures where crystallite sizes are too large for estimation using the Scherrer formula. Density and SSA measurements performed as a function of heat-treatment temperature indicate that a PWT increases the density of air-dried microspheres, creates a pore network, and that significant densification occurs between 450 and 750 °C. These results may be used to inform decisions on internal gelation flowsheet parameters to optimize the microsphere formation and gelation step, prevent microsphere cracking, and produce microspheres suitable for subsequent coating operations or pressing into pellets.

Alumina aerogels are obtained by the sol–gel synthesis and subsequent supercritical drying. The sol–gel synthesis is carried out by adding epichlorohydrin to aluminum chloride dissolved in water and ethanol. The supercritical drying (SCD) of the gels is carried out in a medium of supercritical carbon dioxide SC-CO2 at 40°C and 12.0 MPa for 8 h. The structural characteristics of the aerogels are studied by low-temperature adsorption of nitrogen, helium pycnometry, and scanning electron microscopy. The obtained aerogels have a high specific surface area (up to 764 m2/g) and a high level of porosity (up to 96.2%, with the pore volume of up to 4.9 cm3/g), as well as a low density (up to 0.066 g/cm3). It is found that the structural characteristics of the alumina aerogels can be controlled by varying the water : precursor ratio. In particular, increasing this ratio leads to an increase in the specific surface area and pore volume.

Nanostructured hollow Co3O4 spheres are synthesized by ultrasonic spray pyrolysis. Nanocrystals forming the sphere structure have different sizes and packing density, depending on the synthesis conditions. The samples are studied by X-ray diffraction, scanning electron microscopy, low-temperature nitrogen adsorption, vacuum pycnometry, and Raman and X-ray photoelectron spectroscopies. The field and temperature dependences of magnetization show that the magnetic properties and the Neel temperature of Co3O4 hollow spheres are determined by the size and packing density of nanocrystals.

Nanocrystalline BiFeO3-based powder materials with an average crystallite size near 40 nm have been prepared by solution combustion synthesis from bismuth and iron nitrates using sucrose and tartaric acid as fuel. The materials have been characterized by X-ray diffraction, helium pycnometry, scanning electron microscopy, energy dispersive X-ray microanalysis, and Mossbauer spectroscopy. Magnetometry results demonstrate that the magnetic response of the materials varies over several orders of magnitude, depending on the synthesis procedure.

The density of aqueous solutions of light fullerene С60 in binary system C60(OH)24–H2O is studied via pycnometry. The concentration dependences of the molar volumes and partial molar volumes of the components (Н2О and corresponding fullerenol) are calculated for the binary C60(OH)24–H2O system at 25°С. The linear sizes and the electrokinetic potentials and mobilities of the associates in the given system are studied via dynamic light scattering.

In the 1990s, closed and open porosity volumes of firn samples were measured by J.-M. Barnola using the technique of gas pycnometry, on firn from three different polar sites. They are the basis of a parameterization of closed porosity in polar firn, first introduced in Goujon et al. (2003) and used in several firn physics models (e.g., Buizert et al., 2012). However, these data and their processing have not been published in their own right yet. In this short article, we detail how they were processed by J.-M. Barnola and how the closed porosity parameterization was obtained. We show that the original data processing only partially accounts for the presence of reopened bubbles in the samples. Since the proper correction to apply for this effect is hard to estimate, we also processed the data without including a correction for reopened bubbles. Finally, we made these pycnometry data available in order to be used by the glaciology community, notably for the study of polar ice formation and of the composition of gas records in ice cores. They are hosted on the PANGAEA database: https://doi.org/10.1594/PANGAEA.907678 (Fourteau et al., 2019a).

Gas pycnometry and mercury porosimetry are used to investigate the porous network of Gilsocarbon nuclear graphite samples that are representative of the material present in the cores of UK Advanced Gas-Cooled reactors at different stages of the reactors’ operational lifetimes. Irradiation and radiolytic oxidation change the pore volume of nuclear graphite and the relative ratios of open (coolant gas accessible) and closed pore volume. Particular focus has been paid to the deformation of the Gilsocarbon graphite observed during mercury intrusion at high pressure, which has previously marred the use of porosimetry to characterise this material. The results show clear trends in the evolution of the Gilsocarbon graphite porous space. Semi-quantitative deductions are made that will assist the modelling of the evolution of the pore space in the context of the safe extension of the reactors’ working lifetimes.

Crushing and grinding of carbonaceous shale samples is likely to enhance the accessibility of pores and embedded organic matter as compared to the intact rock. This may lead to an overestimation of the total (volume and sorptive) gas storage capacity. In order to investigate the importance of these effects we have measured unconfined apparent grain densities (helium pycnometry) and methane sorption capacities (high-pressure methane excess sorption) of four carbonaceous shales (Cambro-Ordovician Alum Shale, Jurassic Kimmeridge Clay, Jurassic/Cretaceous Bazhenov Shale, and Late Cretaceous Eagle Ford Shale) as a function of particle size. Measurements were first conducted on 38 mm diameter core plugs, which then were crushed and milled to successively smaller particle sizes (μm, and μm). Apparent grain densities of the smallest particle fractions of the Alum, Bazhenov and Kimmeridge samples were consistently higher by 0.5 to 1% than apparent grain densities of the original sample plugs. Methane excess sorption capacity increased significantly for particle sizes <64 μm for the Alum and μm for the Bazhenov and Kimmeridge samples while no significant changes upon grinding were observed for the Eagle Ford Shale. For the Bazhenov Shale, the apparent grain density increased slightly from 2.446 g/cm3 to 2.450 g/cm3 upon particle size reduction from μm to μm while the maximum sorption capacity (“Langmuir volume”) increased substantially from 0.11 mmol/g to 0.19 mmol/g. Similarly, for the Kimmeridge Clay and Alum Shale, a slight increase of the apparent grain density from 1.546 g/cm3 to 1.552 g/cm3 and from 2.362 g/cm3 to 2.385 g/cm3, respectively, was accompanied by increases in sorption capacity from 0.37 mmol/g to 0.45 mmol/g and from 0.14 mmol/g to 0.185 mmol/g, respectively. The increase in sorption capacity indicates an opening of a considerable amount of micropores with large internal surface area upon physical disruption of the rock fabric and/or removal of included fluids. It may also be due to increased swelling abilities of clay minerals and organic matter upon destruction of the stabilizing rock fabric with decreasing particle size. Grain density and sorption isotherms measured on small particle sizes are likely to overestimate the gas storage capacities and the amounts of producible gas-in-place since under field conditions (largely undisrupted rock fabric), significant portions of this storage capacity are essentially inaccessible. Poor interconnectivity of the pore system and slow, diffusion-controlled transport will massively retard gas production. Based on these findings, particle sizes >64 μm should be used for porosity and sorption measurements because they are more likely to retain the properties of the rock fabric in terms of accessible pore volume and sorptive storage capacity.

International audience; Two foods, belonging to different protein sources (dairy vs plant), namely Emmental cheese and tofu, were treated by the instant pressure drop (DIC) process inserted between two drying stages to obtain expanded and crispy snacks. This process consisted of a short heating step (t = 38-52 s) using steam under pressure (p = 0.26-0.62 MPa) and instantaneous pressure drop toward a vacuum. This pressure drop provoked auto-vaporization of the superheated liquid, which resulted in volume expansion, and cooling of the food. The expansion was visualized using a rapid camera at a frequency of 1000 images/s. The pressure and temperature histories were registered simultaneously. Three expansion ratios were evaluated: (i) r the ratio of food volumes after and before DIC process measured using sand pycnometry, (ii) r c calculated from dimensions measured by a caliper, and (iii) r(1) calculated from dimension reading from images. The shrinkage s = (r(1)/r(C)) -1, and the deformation d = (r(C)/r) -1 of the samples were then evaluated. Using response surface methodology, the optimal processing conditions for maximum expansions r = 2.5 and r(C) =4.5 were found for Emmental and tofu, respectively as p = 0.5 and 0.62 MPa, t=40 and 38s. The creation of mist, inherent to the pressure drop of steam, made the visual observation impossible at the beginning of pressure drop. The samples were already expanded when the mist disappeared. Taking the mist presence as the upper limit of expansion time, the expansion took dozens of milliseconds at a pressure drop rate of 1.25 MPa/s. The temperature in the reactor decreased at a rate of 750 degrees C/s. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Hybrid manufacturing is often used to describe a combination of additive and subtractive processes in the same build envelope. In this research study, hybrid manufacturing of 18Ni-300 maraging steel was investigated using a Matsuura LUMEX Avance-25 system that integrates metal additive manufacturing using laser powder bed fusion (LPBF) processing with high-speed machining. A series of benchmarking coupons were additively printed at four different power levels (160 W, 240 W, 320 W, 380 W) and with the integration of sequential machining passes after every 10 deposited layers, as well as final finishing of selected surfaces. Using non-contact three-dimensional laser scanning, inspection of the final geometry of the 18Ni-300 maraging steel coupons against the computer-aided design (CAD) model indicated the good capability of the Matsuura LUMEX Avance-25 system for net-shape manufacturing. Linear and areal roughness measurements of the surfaces showed average Ra/Sa values of 8.02–14.64 µm for the as-printed walls versus 0.32–0.80 µm for the machined walls/faces. Using Archimedes and helium (He) gas pycnometry methods, the part density was measured to be lowest for coupons produced at 160 W (relative density of 93.3–98.5%) relative to those at high power levels of 240 W to 380 W (relative density of 99.0–99.8%). This finding agreed well with the results of the porosity size distribution determined through X-ray micro-computed tomography (µCT). Evaluation of the static tensile properties indicated that the coupons manufactured at the lowest power of 160 W were ~30% lower in strength, 24% lower in stiffness, and more than 80% lower in ductility relative to higher power conditions (240 W to 380 W) due to the lower density at 160 W.

Porosity is frequently specified as only a value to describe the microstructure of a battery electrode. However, porosity is a key parameter for the battery electrode performance and mechanical properties such as adhesion and structural electrode integrity during charge/discharge cycling. This study illustrates the importance of using more than one method to describe the electrode microstructure of LiNi0.6Mn0.2Co0.2O2 (NMC622)-based positive electrodes. A correlative approach, from simple thickness measurements to tomography and segmentation, allowed deciphering the true porous electrode structure and to comprehend the advantages and inaccuracies of each of the analytical techniques. Herein, positive electrodes were calendered from a porosity of 44–18% to cover a wide range of electrode microstructures in state-of-the-art lithium-ion batteries. Especially highly densified electrodes cannot simply be described by a close packing of active and inactive material components, since a considerable amount of active material particles crack due to the intense calendering process. Therefore, a digital 3D model was created based on tomography data and simulation of the inactive material, which allowed the investigation of the complete pore network. For lithium-ion batteries, the results of the mercury intrusion experiments in combination with gas physisorption/pycnometry experiments provide comprehensive insight into the microstructure of positive electrodes.

Pycnometric and homologous series retention methods are used to determine the volume and mean composition of the water-rich layers partially adsorbed on the surface of several hydrophilic interaction liquid chromatography (HILIC) column fillings with acetonitrile-water and methanol-water as eluents. The findings obtained in this work confirm earlier studies using direct methods for measuring the stationary phase water content performed by Jandera's and Irgum's research groups. Water is preferentially adsorbed on the surface of the HILIC bonded phase in hydroorganic eluents containing more than 40% acetonitrile or 70% methanol, and a gradient of several water-rich transition layers between the polar bonded phase and the poorly polar bulk mobile phase is formed. These layers of reduced mobility act as HILIC stationary phases, retaining polar solutes. The volume of these layers and concentration of adsorbed water is much larger for acetonitrile-water than for methanol-water mobile phases. In hydroorganic eluents with less than 20-30% acetonitrile or 40% methanol the amount of preferentially adsorbed water is very small, and the observed retention behavior is close to the one in reversed-phase liquid chromatography (RPLC). In eluents with intermediate acetonitrile-water or methanol-water compositions a mixed HILIC-RPLC behavior is presented. Comparison of several HILIC columns shows that the highest water enrichment in the HILIC retention region for acetonitrile-water mobile phases is observed for zwitterionic and aminopropyl bonded phases, followed in minor grade for diol and polyvinyl alcohol functionalizations. Pentafluorophenyl bonded phase, usually considered a HILIC column, does not show significant water adsorption, nor HILIC retention.

The surface properties of three commercial ionomer glass powders, i.e., Fuji IX, Kavitan Plus and Chemadent G-J-W were studied. Samples were analyzed by X-ray fluorescence spectroscopy (XRF), and the density was determined by gas pycnometry. Morphology was studied using scanning electron microscopy (SEM) and laser diffraction (LD) technique, whereas low-temperature nitrogen sorption measurements determined textural parameters like specific surface area and pore volume. Thermal transformations in the materials studied were evaluated by thermogravimetric analysis (TGA), which was carried out in an inert atmosphere between 30 °C and 900 °C. XRF showed that Fuji IX and Kavitan Plus powders were strontium-based, whereas Chemadent G-J-W powder was calcium-based. Powders all had a wide range of particle sizes under SEM and LD measurements. Specific surface areas and pore volumes were in the range 1.42–2.73 m2/g and 0.0029 to 0.0083 cm3/g, respectively, whereas densities were in the range 2.6428–2.8362 g/cm3. Thermogravimetric analysis showed that the glass powders lost mass in a series of steps, with Fuji IX powder showing the highest number, some of which are attributed to the dehydration and decomposition of the polyacrylic acid present in this powder. Mass losses were more straightforward for the other two glasses. All three powders showed distinct losses at around 780 °C and 835 °C, suggesting that similar dehydration steps occur in all these glasses. Other steps, which differed between glass powders, are attributed to variations in states of water-binding on their surfaces.

Growing applications of additive manufacturing (AM) have now been adopted for metal castings via indirect hybrid AM, i.e., 3D sand printing (3DSP). A comprehensive study on the thermo-physical properties of 3DSP molds based on 3DSP processing conditions and their effects on materials and mechanical properties of resulting aluminum castings is presented. The effect of furan binder content (i.e., 1–3%) on as-printed 3DSP molds is evaluated to determine changes in dimensional accuracy, density (helium pycnometry), actual binder content (loss on ignition) and mechanical strength (three-point bending and tensile testing) and thermal properties (transient plane source technique and casting runs). Pore network characterization via mercury intrusion porosimetry does not reveal any significant differences in the morphology of pore structures due to varying binder concentrations. However, bulk permeability is reduced with increasing binder content. Thermal analysis shows a reduction in conductivity and heat capacity due to binder degradation. Findings from this study will enable the optimum selection of binder content for functional grading of 3DSP molds/cores for adequate degassing and mechanical strength, which is ready for adoption by both foundries and 3DSP service providers.

The characteristics of non-connected pores of four Longmaxi shale samples from the southern Sichuan Basin of China were investigated from the studies of pore size distribution (PSD), pore volumes, pore types using helium pycnometry [gas injection porosimetry (GIP) and GRI (Gas Research Institute) method], nuclear magnetic resonance (NMR), nuclear magnetic resonance cryoporometry (NMRc), and spontaneous water and oil imbibition experiments. GRI porosity on particle sizes less than 5 mm sample and a 2 MPa helium injection pressure provides information on the total porosity, including both non-connected and connected pores. GIP porosity using core plugs only measures connected pores which extend to the surface of the sample accessible by helium. So the difference between GRI and GIP porosities is used to estimate the volumes of non-connected pores. And the volumes of non-connected pores accounts for 17.5%–40.3% of the total pore volume. For NMRc test results, total pore volume increases with sample size decrease, and the great difference of pore volume with a pore diameter range from 5 nm to 31 nm between small cylinder sample and 0.15–0.075 mm crushed sample is caused by non-connected pores opened. With a decrease of length for cubic samples, the increase in volume and rate of oil imbibition is greater than that of water imbibition, indicating that the non-connected pores are considered to be mainly oil-wet. In addition, the percentage of non-connected pores has a good correlation with TOC (total organic carbon) content. Therefore, this evidence implies that non-connected pores are mainly within the organic matter. NMR tests at different drying temperatures and a NMRc experiment provide a quantitative classification of the shale pore system which indicates that the exploitable pore diameters are larger than 4.25 nm. So non-connected pores with a diameter of 5–31 nm could be effectively exploited if connected by fracturing. The more the non-connected pores are opened, the better the pore connectivity of shale reservoir will be, with a less possibility of water blocking. In the process of shale gas development, attention should be paid to the interaction between fracturing fluid and rock components in order to release more non-connected pores. Therefore, to increase shale gas extraction efficiency, more effort should be directed towards identifying natural, and creating induced, porosity.

The petrophysical characteristics of unconventional reservoirs have significant impacts on hydrocarbon storage and transport. In this study, 26 shale samples with various lithofacies from Lower Silurian Longmaxi shales in the Jiaoshiba area of Sichuan Basin are investigated. The pore network (morphology, porosity, and pore structure parameters) is comprehensively characterized using scanning electron microscopy, helium pycnometry, and low-pressure gas adsorption techniques. Permeability coefficients are derived from pulse-decay measurements on parallel to bedding samples. Geological controls on the pore shape, porosity, pore size, pore size distribution, and permeability of the shales are analyzed, and quantitative relationships with which to estimate the permeabilities and pore-throat apertures controlling gas flow are developed. Three general lithofacies are summarized in view of their mineralogy: siliceous, argillaceous/siliceous mixed, and argillaceous shales. Pore structure parameters (porosity, specific surface area, and pore volume) show positive correlations with total organic carbon (TOC) content. Organic matter-hosted pores contribute to approximate 67% of the porosity of siliceous shales, while inorganic matter contributes to 55% of the porosity of argillaceous shales. Klinkenberg-corrected permeabilities range between 0.01 and 46.4 μD, and are controlled by the alignment of clay flakes. Negative relationships exist between TOC content, porosity, and permeability values. Siliceous shales generally have the lowest permeabilities, whereas the argillaceous shales with developed oriented clay flakes have relatively high permeabilities. The seepage-pore apertures, estimated using the Winland correlation, range from 9 to 476 nm. These values are much higher than those obtained from nitrogen adsorption analysis (adsorption-pore apertures). A power correlation exists between seepage-pore apertures and total clay minerals content of shales studied. A fracture model (sheet) is used to predict absolute permeability based on seepage-pore apertures. The predictions are reasonable, and justify the application of the sheet model and seepage-pore apertures. The siliceous shales are featured by a high TOC content, large porosity and specific surface area, and low permeability, which are favorable to gas preservation.

Nanocrystalline powders of VCy with different stoichiometry and the average particle size were produced by high-temperature solid-phase synthesis and subsequent milling. The crystal structure, phase composition, microstructure and particle morphology of initial and milled VCy powders, their specific surface area and density were studied using XRD, SEM, BET method and gas pycnometry. The anisotropy of microstrains in nanocrystalline VCy powders was experimentally studied by XRD. It was shown that the inclusion of microstrain anisotropy and inhomogeneous broadening in the analysis make it possible to more accurately describe experimental data on diffraction reflection broadening. It was found that microstrains mainly contribute to the broadening of diffraction reflections of VCy nanopowders produced by milling. The experimental dependence of the pycnometric density of VCy powders on the specific surface area was established and an expression describing it was obtained. It was shown that the main reason for pycnometric density reduction of the powders with increasing specific surface area is oxygen adsorption on the surface of carbide particles.

8 Figuras, 3 Tablas.-- Información suplementaria disponible en la página web del editor., For the first time, a mayenite based material combining calcium and copper (18.0/37.6/44.4 estimated active wt % CaO/CuO/Ca12Al14O33, CuO/CaO = 2.1 [wt/wt]) has been subjected to three full calcium–copper chemical looping combustion (Ca–Cu Looping) cycles in a fixed bed reactor (70.0 g of combined material and 3.5 g of 18.0 wt % Ni/Al2O3 reforming catalyst), demonstrating the feasibility of a combined materials approach to hydrogen production through Ca–Cu Looping. Combined materials were characterized by helium pycnometry, mercury intrusion, nitrogen adsorption, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and energy dispersive X-ray diffraction before and after reactor testing. A carbon dioxide capture capacity of 14.6–15.0 g CO2/100 g (640–660 °C, 1.0 MPa, 2.5 kgCH4 kgcat–1 h–1), full oxidation, and expected calcination efficiencies (51–64%) were obtained. Combined material performance is comparable to that of segregated materials previously tested in the same experimental rig. Process intensification of Ca–Cu Looping through combined materials development is promising., The work is funded by the Research Council of Norway (NFR) within the CLIMIT program – “Innovative Materials for CO2 Capture by Combined Calcium–Copper Cycles” (project number 254736).

When sandstone rocks are exposed to CO2-saturated brine, their transport and mechanical properties can change due to brine/CO2-induced chemical reactions. The present study investigates the change in the flow-through characteristics, porosity, and the mechanical behavior of Mt. Simon Sandstone samples caused by exposure to brine/CO2. The cores, extracted from a depth interval of 2110.4–2111.4 m (6924–6927 ft) in the Mt. Simon formation, were first characterized for their mechanical and transport properties, and then aged in CO2-saturated brine at pressures of 17.24 MPa (2500 psi) and temperature of 50 °C for one to two weeks. Following that, the changes in the transport and mechanical properties of the samples were analyzed using He pycnometry, flow perporometry and triaxial testing. Our experiments show that the porosity of the Mt. Simon samples slightly increases after exposure to CO2/brine, while the permeability increases more substantially depending on the stress state. Measurements of the flow-through pore size distribution (PSD) are indicative of the changes occurring and are consistent with the observed increases in permeability. Nitrogen adsorption tests (BET), before and after incubation, show a significant loss of pore volume in the mesoporous range that is indicative of clay dissolution. Weakening of the materials was observed based on the mechanical properties studied, a result that is consistent with the observed dissolution of clays that play a central role in the cementation of the quartz grains. Finally, the analysis of the brine compositions reveals an increase in concentration of most cations after incubation with the Mt. Simon cores. This is also consistent with mineral/clay dissolution, confirmed by the porosity, transport, and mechanical property measurements as well as electron microscopy analysis of the same samples.

Stereolithographic 3D printing is of paramount interest for researchers studying porous media because it is possible to use resins with a wide range of physical and chemical properties. Currently, these properties can be designed and adjusted to model the interaction of solids with fluids occupying the pore space, which is not feasible with natural materials. This ability enables replicating the pore network geometry of natural rocks as well as tuning the wettability of pore network surfaces. This study presents analysis of uncured liquid resins and porous rock models 3D-printed in those resins to establish the accuracy of the stereolithographic 3D printer in repeatedly printing the same pore network, as well as the fidelity of transport properties (e.g., porosity, pore sizes, wettability) to the model design. Viscosity of uncured resins was measured to predict the physical properties of the resulting cured models. A digital model of Fontainebleau sandstone was 3D-printed at three magnifications (15-, 23-, and 30-fold) from the original tomographic volume of 1 mm3 and in six resins (black, gray, clear, white, green, and yellow). The models were validated using the following techniques: helium pycnometry (for porosity); mercury porosimetry (for pore-throat size); and drop shape analyzer (for contact angles). Validation tests showed that green resin had the highest accuracy in replicating the rock’s pore network. White, yellow, and gray resins produced models with moderate accuracy with respect to their transport properties. Black and clear resins had the lowest accuracy and would need further analysis of their physical and chemical properties to be useful in reservoir rock replication.

Carbon foams were prepared from coal tar pitch modified by treatment with concentrated nitric acid followed by foaming and carbonization. Effect of particle size of the precursor, heating rate during foaming and foaming time on the porosity and compressive strength was investigated. Precursor particle size was varied from 75 to 500 μm. Heating rate during foaming was varied from 3 °C/min to 5 °C/min. Three foaming times of 1 h, 3 h and 5 h were also studied. Experiments show that fine particle was suitable for foaming as it yields higher strength compared to coarse particle. Three hour of foaming time was sufficient for foaming. Heating rate of 3 °C/min resulted in higher bulk density and compressive strength than that of 5 °C/min. Carbon foam of 0.56 g/cc bulk density along with 35.45 MPa compressive strength and 71% porosity is obtained by using 75-μm particle and 3 °C/min heating rate with 3 h of soaking time. True density of the foams was obtained by helium pycnometry. Compressive strength and morphology was tested in universal strength testing machine and scanning electron microscope respectively.

Palaeogene calcareous (>40% carbonate) mudstones (Ro from 0.56 to 0.88%) from the Bohai Bay Basin were studied by combined petrographical, geochemical and petrophysical analysis in order to assess and quantify the pore space, pore filling and its influence on gas transport capacity. TOC contents ranged from 1.44% to 5.12% and porosities (ΦHe) determined by helium pycnometry, from 1.3% to 6.4%. Bitumen-filled porosity (ΦS1) was estimated to range between 0.3 and 2.0% based on Rock-Eval S1 values and an assumed bitumen density of 0.90 g/cm3. The “true” total porosity (Φtotal = ΦHe + ΦS1) amounts to 1.9–8.5%. The in-situ oil saturation (So) was estimated to range between 25% and 52%, with two samples (L69-1B and L69-2) having relatively high oil saturation (71% and 91%). The conductivity of the remaining “open” pore space was measured on three samples with different orientations and oil saturations from 17 to 24%. The effective Klinkenberg-corrected gas permeability coefficients range between 63 and 2000 nDarcy, and permeability is highest parallel to bedding. Upon loading from 10 to 40 MPa confining pressure the intrinsic permeability coefficients decreased by one order of magnitude, revealing a relatively high exponential stress sensitivity coefficient (0.069 MPa−1) and much lower zero stress permeability (1.416 × 10−6 mD) than most gas shales. This could be due to pore plugging by ductile bitumen.

N2 adsorption isotherms at ca. 77 K on macroporous α-Al2O3 have been measured and analyzed in the frameworks of the classic thermodynamic approach, with independent experimental data obtained by means of SEM-EDX, XRD, TGA, helium pycnometry, and mercury porosimetry taken into account. It is shown, that presence of adsorbed water considerably influences N2 adsorption, which gradually increases with temperature of the degas treatment. Simultaneously, the shape of the isotherms has a trend to change from Type II to Type VI, that assumes changing of adsorption mechanism from progressive increasing of the adsorbed layer thickness towards layer-by-layer adsorption. Corrected and smoothed isotherms are presented in the tabular form as reference for subsequent more comprehensive analysis using molecular statistical approaches.

For oil-rich shales, current solvent extraction– and thermal extraction–based methods inaccurately measure hydrocarbon-filled porosity (vHC). Moreover, the hydrocarbon composition is not characterized by either method. Here, we show how open-system programmed thermal extraction and pyrolysis, LECO total organic carbon, Archimedes bulk density, and helium pycnometry measurements are integrated to calculate oil and gas pore volumes, characterize their composition, and estimate mobility. Use of a modified multiramp, slow-heating thermal extract, and pyrolysis temperature program further subdivides the vHC. Saturate–aromatic–resin–asphaltene (SARA) separation and gas chromatography of solvent-extracted organic matter and thermally extracted oils are used to compositionally classify the vHC. The segregated bulk compositions of gas- and oil-filled porosity measured via this method are shown to overlap and are broken into the following categories: gas-filled porosity (∼C1–C14), light oil–filled porosity (∼C6–C36), and heavy oil–filled porosity (∼C32–C36+). Furthermore, slow-heating multiramp thermal extraction can subdivide the light oil–filled porosity into four components capturing the C11–C13, C12–C16, C14–C20, and C17–C36 ranges of the extractable organic matter. Analysis of solvent-extracted oils by SARA identifies abundant saturates and aromatics in the light oil–filled porosity and abundant resins and asphaltenes in the heavy oil–filled porosity. Low-maturity shales can be dominated by heavy (C32+) oils rich in asphaltene and resin fractions not observed in the produced fluid. The ratios of SARA components in the C15+ fraction of produced fluid and core extract can be used to better estimate the potentially mobile vHC.

When investigating the gas storage capacities of metal-organic frameworks, volumetric values are often reported based on crystallographic densities. Although it is widely accepted that Langmuir and BET surface areas of a given MOF can vary depending on the exact synthetic conditions used to prepare the materials, it is rare that deviations in density from the optimal crystallographic density are considered. The actual (apparent) densities of these materials are highly variable depending on the presence of defects, impurities, or multiple phases that arise during synthesis. The apparent density of specific samples, which represent an experimentally determined crystallographic density, can be measured with helium pycnometry where the skeletal density measured via pycnometry is easily converted to an apparent density. In the work reported here, apparent density was measured for 46 samples across a series of different structure types where experimentally measured density was consistently lower than crystallographic density, up to 30% in some cases. Subsequently, use of this technique allows for quantification of densities for those materials whose structures have not been crystallographically determined.

This paper concerns the packing of plant particles (hemp shiv) used for building applications and aims to quantify skeletal, particle and packing densities and associated porosities. These parameters were measured on hemp particles as a case study and were used to assess the physical behaviour of this material in terms of water adsorption and absorption, mechanical compression and thermal and acoustic behaviours. A number of experimental methods have been used to characterise these parameters including fluid and powder pycnometry, mercury intrusion and X-ray computed tomography, leading to robust and complementary results as a function of particle size and level of aging by immersion in water. It was concluded that smaller particles are characterised by higher packing and particle densities, while aged particles present a strong evolution of their microstructure, which is visible through lower packing and particle densities and higher skeletal density. By comparing these experimental results with physical property characterisations, correlations were found between water absorption and open porosity, compression behaviour and the three density scales, and between acoustic dissipation and intra- and inter-particle porosities.

A nondestructive iterative method for uranium-bearing material characterization with HRGS developed earlier in Burdeinyi et al. (2020) is applied to determine matrix densities, uranium mass fraction and uranium isotope masses of uranium ore, UO 2 and U 3 O 8 powders, fuel elements in the form of UO 2 microspheres, uranium metal and uranium alloys. It is shown that U 3 O 8 powders with uranium mass fraction of about 84% can be distinguished from the powders of UO 2 with uranium mass fraction of about 87%; uranium products in the form of liquid or loose powder with matrix density of 0.5–2.0 g/cm 3 can be distinguished from uranium products in the form of compacted fuel elements with matrix density of 6.0–10.0 g/cm 3 and from pure metal uranium and uranium alloys with matrix density of 14.0–19.0 g/cm 3 . In fuel microspheres based on UO 2 the uranium mass fraction 88.02% measured by HRGS is consistent, within the measurement uncertainties, with the results of isotope dilution mass spectrometry 87 . 76 ± 0 . 64 % and also is confirmed by X-ray diffraction technique. The uranium mass fraction of the uranium ore estimated as 0.08% by HRGS is consistent, within the measurement uncertainties, with the value 0 . 09 ± 0 . 01 % determined with WDXRF. Densities of two different uranium metal samples, estimated as 18 . 42 g/cm 3 and 19 . 33 g/cm 3 by HRGS are consistent with values 18 . 24 ± 0 . 55 g/cm 3 and 18 . 86 ± 0 . 59 g/cm 3 , respectively, obtained by the gas pycnometry technique.

While the US nut industry is growing, markets for nut by-products, particularly nutshells and tree prunings, have not kept pace. Torrefaction is a thermochemical process used to improve physicochemical properties of biomass for energy and other applications. The goal of the paper was to characterize the effects of a range of torrefaction conditions on the properties of nut by-product feedstock. The process consists of thermal treatment of biomass at a temperature between 200 and 300°C in the absence of oxygen, where final material properties of the torrefied biomass depend on the temperature, heating rate, and residence time. In general, torrefied biomass exhibits higher hydrophobicity and calorific value with reduced moisture absorption compared to untreated biomass, making it an ideal fuel source for energy applications compared to raw biomass. In this study, almond shells of soft, semi-soft, and hardshell varieties, as well as walnut shells and almond wood, were torrefied at two different temperatures (230 and 290°C) and three different residence times (20, 40, and 60 min) in order to characterize the physicochemical properties. The thermal behavior of raw and heat-treated biomass was investigated by TGA analysis, elemental analysis, pH, helium pycnometry, FTIR spectroscopy, and dynamic vapor sorption analysis.

The density of Te, HgTe, Hg0.9Cd0.1Te, Hg0.8Cd0.2Te, Hg0.9Zn0.1Te and Hg0.84Zn0.16Te melts were measured by a method similar to the pycnometric technique which measures the volume of a melt, with known mass, in a sealed fused silica ampoule positioning coaxially inside a transparent furnace. The volume was determined from the height of the meniscus, by in situ visual observation, and the calibration of volume vs. height for the ampoule which was performed by measuring the mass of water at different heights before the sample was loaded. The density measurements covered the temperature ranging from the corresponding melting points or liquidus temperatures to about 1130 K. The Te liquid showed the normal thermal expansion, i.e., its density decreases as temperature increases except at temperatures just above the melting point where it went through a maximum. Similar to the behavior of the Te melt, the density of HgTe, Hg0.9Cd0.1Te melts also went through a maximum as a function of temperature. It has been reported by other measurements, such as neutron scattering and nuclear magnetic resonance, that the melt consists of a mixture of two domains—one with low-coordination number and the other with high-coordination number structure which corresponding to low- and high-density melt, respectively. At temperature just above the melting point, the melt structure started to evolve with the low-coordination number domain changing into high-coordination number one which resulted in an increase in melt density. As temperature increasing to the density maximum, most of the structural changes has been completed and the normal thermal expansion took over and the density started to decrease as the temperature keeps on increasing. The measurements on the melts of Hg0.8Cd0.2Te, Hg0.9Zn0.1Te and Hg0.84Zn0.16Te did not show a maximum as functions of temperature probably because the liquidus of these melts are higher than the temperature where the density maximum occurred.

The study extended the applications of powder pycnometry (PP) replacing the commercial enveloper for alternative envelopers (ceramic and carbon microspheres) to determine the envelope density of fine recycled aggregates (FRA) sand fraction. The properties of enveloper material such as particle size distribution, skeletal density and shape (aspect ratio and sphericity) affect the envelope density determination consequently impacts in porosity results by the association of PP and Helium pycnometry (HePyc). The porosity determination by association of HePyc and PP are comparable with mercury intrusion porosimetry analysis for medium sand fraction (0.300–1.180 mm).

Cement composites are often employed in severe conditions. They might be exposed for instance to high temperatures and/or high mechanical loads. However, their properties are mostly measured in laboratory conditions only, so that designers cannot take into account the changes in their material parameters after loading. In this paper, basic physical and chemical characteristics of heat resistant materials based on calcium aluminate cement are analyzed in the temperature range up to 1400 °C and the results are compared to those obtained for reference materials. The basic physical c haracteristics, namely bulk density, matrix density, and open porosity, are measured using helium pycnometry and gravimetric method. Material characterization experiments using thermal analysis and X-ray diffraction measurements are performed as well to assess the effect of high temperature exposure on the composition of studied materials. The experimental results show a very substantial effect of heat resistant admixtures on both physical and chemical characteristics.

Transport in porous media : TIPM 137(3), 519-553 (2021). doi:10.1007/s11242-021-01572-8, Published by Springer Science + Business Media B.V, Dordrecht [u.a.]

CO2 methanation is often performed on Ni/Al2O3 catalysts, which can suffer from mass transport limitations and, therefore, decreased efficiency. Here we show the application of a hierarchically porous Ni/Al2O3 catalyst for methanation of CO2. The material has a well-defined and connected meso- and macropore structure with a total porosity of 78%. The pore structure was thoroughly studied with conventional methods, i.e., N2 sorption, Hg porosimetry, and He pycnometry, and advanced imaging techniques, i.e., electron tomography and ptychographic X-ray computed tomography. Tomography can quantify the pore system in a manner that is not possible using conventional porosimetry. Macrokinetic simulations were performed based on the measures obtained by porosity analysis. These show the potential benefit of enhanced mass-transfer properties of the hierarchical pore system compared to a pure mesoporous catalyst at industrially relevant conditions. Besides the investigation of the pore system, the catalyst was studied by Rietveld refinement, diffuse reflectance ultraviolet-visible (DRUV/vis) spectroscopy, and H2-temperature programmed reduction (TPR), showing a high reduction temperature required for activation due to structural incorporation of Ni into the transition alumina. The reduced hierarchically porous Ni/Al2O3 catalyst is highly active in CO2 methanation, showing comparable conversion and selectivity for CH4 to an industrial reference catalyst.

Two novel, thermally stable explosives, 2-fluoro-1,3-diamino-4,6-dinitrobenzene (ZXC-7) and 2-fluoro-1,3,5-triamino-4,6-dinitrobenzene (ZXC-8), are reported. These two compounds can be prepared by means of simple synthetic methods and they show outstanding properties (detonation velocity, detonation pressure, sensitivity toward mechanical stimuli, and temperature of decomposition). Their structures are very similar to that of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). They were isolated and characterized by means of mass spectrometry and multinuclear (1 H, 13 C) NMR spectroscopy. The structure of ZXC-7 in the crystalline state was determined by low-temperature single-crystal X-ray diffraction. From the calculated standard molar enthalpy of formation (CBS-4 M) and the densities (which were determined by a gas pycnometer), the Chapman-Jouguet detonation properties were predicted by using the EXPLO5 V6.01 thermochemical computer code. The sensitivities of ZXC-7 and ZXC-8 towards impact and friction were determined.

International audience; Nanoparticulate powders are increasingly found in the workplace. Inhalation exposure to airborne nanoparticles (NPs) is possible throughout the life-cycle of the powders. As the toxicity of NPs has never been demonstrated, it remains essential to evaluate the risks associated with NPs in order to propose preventative measures. The first step of a risk assessment strategy consists in the identification of the ‘nano’ nature of a material, which suffers from a lack of an operational methodology. Here, we present a simplified and operational strategy relying on the volume specific surface area (VSSA) for nanomaterial identification, based on the recommendation stemming from the European Commission and previous work on this topic from the European Project Nanodefine. The proposed strategy was tested on a set of 15 representative industrial powders (TiO2, SiO2, CuO, and ZnO), covering a wide range of properties, and previous published data. The VSSA classification was validated via a comparison with the particle size obtained by transmission electron microscopy (TEM). It was evidenced that the VSSA is in accordance with particle size for nanomaterial powder classification. The proposed methodology involves relatively accessible methods such as thermogravimetric analysis, nitrogen adsorption and helium pycnometry and limits the detection of false negatives. Moreover, it does not imply systematic confirmation of the results with the reference particle size criterion. Our results suggest that the VSSA is a promising parameter to be used for risk assessment and should be further investigated on powder mixings to confirm its relevancy to define nanomaterial powders.

Plain or coated pellets of different densities 1.45, 2.53, and 3.61 g/cc in two size ranges, small (380&ndash, 550 &mu, m) and large (700&ndash, 1200 &mu, m) (stereoscope/image analysis), were prepared according to experimental design using extrusion/spheronization. Multiple linear regression (MLR) and artificial neural networks (ANNs) were used to predict packing indices and capsule filling performance from the &ldquo, apparent&rdquo, pellet density (helium pycnometry). The dynamic packing of the pellets in tapped volumetric glass cylinders was evaluated using Kawakita&rsquo, s parameter a and the angle of internal flow &theta, The capsule filling was evaluated as maximum fill weight (CFW) and fill weight variation (FWV) using a semi-automatic machine that simulated filling with vibrating plate systems. The pellet density influenced the packing parameters a and &theta, as the main effect and the CFW and FWV as statistical interactions with the coating. The pellet size and coating also displayed interacting effects on CFW, FWV, and &theta, After coating, both small and large pellets behaved the same, demonstrating smooth filling and a low fill weight variation. Furthermore, none of the packing indices could predict the fill weight variation for the studied pellets, suggesting that the filling and packing of capsules with free-flowing pellets is influenced by details that were not accounted for in the tapping experiments. A prediction could be made by the application of MLR and ANNs. The former gave good predictions for the bulk/tap densities, &theta, CFW, and FWV (R-squared of experimental vs. theoretical data &gt, 0.951). A comparison of the fitting models showed that a feed-forward backpropagation ANN model with six hidden units was superior to MLR in generalizing ability and prediction accuracy. The simplification of the ANN via magnitude-based pruning (MBP) and optimal brain damage (OBD), showed good data fitting, and therefore the derived ANN model can be simplified while maintaining predictability. These findings emphasize the importance of pellet density in the overall capsule filling process and the necessity to implement MLR/ANN into the development of pellet capsule filling operations.

The true density of an amorphous solid is an important parameter for studying and modeling materials behavior. Experimental measurements of density using helium pycnometry are standard but may be prevented if the material is prone to rapid recrystallization, or preparation of gram quantities of reproducible pure component amorphous materials proves impossible. The density of an amorphous solid can be approximated by assuming it to be 95% of its respective crystallographic density; however, this can be inaccurate or impossible if the crystal structure is unknown. Molecular dynamic simulations were used to predict the density of 20 amorphous solid materials. The calculated density values for 10 amorphous solids were compared with densities that were experimentally determined using helium pycnometry. In these cases, the amorphous densities calculated using molecular dynamics had an average percent error of - 0.7% relative to the measured values, with a maximum error of - 3.48%. In contrast, comparisons of amorphous density approximated from crystallographic structures with pycnometrically measured values resulted in an average percent error of + 3.7%, with a maximum error of + 9.42%. These data suggest that the density of an amorphous solid can be accurately predicted using molecular dynamic simulations and allowed reliable calculation of density for the remaining 10 materials for which pycnometry could not be done.

High performance, acceptable thermostability, and low mechanical sensitivity are high-demand properties in the design of competitive materials. Nitrogen-rich compounds are an alternative source of green molecules. Two simple, efficient synthetic routes to a novel material, bis (3-(trinitromethyl) − 1H-1,2,4-triazol-5-yl) methanone, 5, by using inexpensive starting compounds are described. Compound 5 has interesting chemical reactivity with water in the presence of organic solvents to form a gem diol of bis (3-(trinitromethyl) − 1H-1,2,4-triazol-5-yl) methanediol, 5a. All new molecules are well characterized by advanced spectroscopic techniques. The structures of 5·Et2O, 5a·3H2O, and salt 6 are confirmed by single-crystal X-ray analysis. The densities of the solid powder compound 5, and the crystals of 5a·3H2O were measured by a gas pycnometer. The theoretical densities and Explo5 calculations of solvent-free molecules, 5 and 5a, suggest that expanding the functionality of carbonyl-bridged compounds may be an alternative way to achieve high-performing materials.

We report the synthesis of W-doped biopolymer aerogels with potential applications to catalysis. The biopolymers were based on alginate, a cost-efficient natural material, and were prepared in environmentally friendly water/ethanol solutions. Gelation of alginate was induced by crosslinking with Ca2+. The resulting wet-gels were impregnated with an ethanolic solution of the ditungsten complex [W2(μ-OEt)2(OEt)2(EtOH)2Cl4] ({W = W}8+) and were dried with supercritical fluid (SCF) CO2 to yield W-doped alginate aerogels containing 10% w/w tungsten. Dry materials were characterized with FTIR, SEM/EDS, TGA, N2 porosimetry and He pycnometry. The bulk densities were low ( 1000 °C in the literature).

The pore structure characteristics, such as porosity, pore size distribution, and pore connectivity, of tight gas sandstone are crucial for evaluating its reservoir capacity. However, due to multiscale pore size and various pore types in tight sandstone, the characterization of the pore structure can be optimized by combining the multiple fluid invasion methods. In this paper, optical microscopy (OM), gas injection porosimetry (GIP), helium pycnometry, low-pressure N2 adsorption (LPN2A) and mercury intrusion porosimetry (MIP) were applied to investigate the pore structure characterization of tight sandstone from Sbaa Basin, Algeria. The results of OM observation suggest that the pores are composed of dissolution pores, intergranular pores, intragranular pores and microcracks. The porosity obtained by GIP and helium pycnometry is consistent, demonstrating the efficiency of GIP in measuring the porosity. Furthermore, after the small-sized pores (nanometer scale) and large-size pores (micrometer scale) of tight sandstone were investigated by using LPN2A and MIP respectively, it is noteworthy that the combination of the two methods is more appropriate to characterize the full scale of pore size distribution (PSD). The key point is to accurately integrate the measurements obtained from LPN2A and MIP for the estimation of the PSD from the dV/dlog(D) curves. The full scale of PSD proves that the pores are primary macropores if the IUPAC classification is adopted, which seems insufficient to reveal the storage capacity of the tight sandstone reservoir. Accordingly, the pores are more proposed to be classified into nanopores (1 nm - 1 μm), micropores (1–62.5 μm) and mesopores (62.5 μm - 4 mm), which is recommended by Loucks et al. (Loucks et al., 2012). Additionally, by comparing the permeability predicted from the inflectional pore throat and/or porosity with the measured permeability, it was found that the effect of the inflectional pore throat on the permeability is more remarkable than that of porosity.

The paper dealt with research on structural properties of metallurgical sinter. It was aimed at studying of sinter porosity and density in relation to its reducibility. For porosity determination was used immersion technique using Archimedes principle. Density was measured by gas pycnometer and apparent density was calculated from results of measured porosity. These properties were studied in relation to temperature 950 °C at which reducibility tests of every sample were carried out according to ISO 4695:2007. For the study 7 batches of 5 samples of sinter originated from industrial metallurgical plant were sorted. The porosity and density were discussed for virgin samples before the test of reducibility and for reduced samples after ISO test. The effect of 950 °C on the properties was contemplated and SEM analysis was carried out. The samples porosity before reduction test was in range from 5.1% to 9.82% and for the samples after reduction test it was 32.77–44.12%. The density of samples was not significantly affected by temperature with values ranging from 3.65 to 3.82 g cm−3 for virgin samples, resp. 4.87–5.37 g cm−3 for samples after reduction. Keywords: Sinter, Reduction, Porosity, Density, Structure

Float and sink testing is the standard laboratory method for determining the coal washability characteristics using heavy liquids. In this paper, we describe an alternative technique for determining coal washability using High-Resolution X-ray Microcomputed Tomography (HRXMT). Specifically, the application of HRXMT and specialized software have enabled us to determine the particle characteristics of coal samples with the considerable details needed for building washability analysis. Coal samples taken from the feed streams to the dense medium circuits at two plants in Australia were obtained, characterized and used in the analysis. The coal samples were fractioned into the size and density fractions using sieves and heavy liquids as per the Australian Standard AS 4156.1-1994. The fraction-averaged densities were determined using helium gas pycnometry. The float and sink results were obtained for calibration and validation of the HRXMT results. Our results show that HRXMT can be used to perform coal washability analysis. It provides a new methodology for non-destructive and non-toxic determination of coal washability data. It is safe and fast. Significantly, the successful applications of X-ray computed tomography to perform coal washability analysis would allow for developing an on-line coal washability monitoring system, which would not be achievable with the traditional float-and-sink analysis.

Calcined biocokes were successfully produced from wood precursors through pyrolysis at high temperature (1200 °C). The resultant material mimics the microstructure of calcined petroleum coke and presents high carbon content, making them a potential raw material for carbon anodes used for the production of aluminum. The properties of these biocokes that are important for anode production, such as real density, crystalline length, carbon content, particle surface area, and chemical surface characteristics, were determined using gas pycnometer, energy dispersive X-ray spectroscopy, BET, and FTIR. The microstructure and the morphology of biocokes were characterized using SEM. The degree of structural disorder in the biocokes was evaluated by Raman spectroscopy. The objective of this work is to study how the partial replacement of calcined petroleum coke by a biocoke affects the properties of corresponding laboratory anodes. Also, an anode without any biocoke was fabricated as a standard for comparison with th...