Porosity Measurements Research Articles

Evolving multispectral sensor configurations using genetic programming for estuary health monitoring

ABSTRACT Assessing ecosystem health on a large scale is crucial for a wide range of management and regulatory decisions. Technologies such as hyperspectral imaging allow noninvasive and rapid estimation of key attributes based on observed reflectance. However, these images are high-dimensional and real-world applications require models based on fewer wavelengths. This paper proposes a new wavelength selection and feature extraction method for hyperspectral image analysis based on genetic programming to automatically select key wavelength regions and informative image features. A dataset of hyperspectral images of sediment in the field was collected and paired with ground-truth measurements of the sediment porosity and organic matter content. Two new program structures were proposed to construct feature extraction trees from either the mean reflectance spectra (spectra-based) or full hyperspectral images (image-based). SVR models were constructed to predict attributes based on the extracted features. Various regression models were used to predict the porosity and organic matter content. Full-wavelength models were constructed to reliably predict the organic matter content. The proposed spectra-based genetic programming solutions show competitive results compared to common wavelength selection methods, such as SPA, CARS, and RC. Finally, the best-evolved solution was applied to predict sediment organic matter content across all collected images.

Controlled release in sodium alendronate/halloysite/hydroxyapatite/gelatin nanocomposite scaffolds: A new insight into bone tissue engineering

The use of smart scaffolds with drug release capabilities is now widely recognized as a key approach in designing hard tissue substitutes. In this study, alendronate sodium (AL) was bound to halloysite nanotube (HNT) sheets through ionic and π-π interactions. Hydroxyapatite (HA) powder was synthesized using the co-precipitation method, and the drug/carrier complex was subsequently incorporated into a hydroxyapatite/gelatin (GEL) matrix. Composite scaffolds of GEL/HA/HNT/AL were then created using a freeze-drying technique. Different concentrations of HNT (0.5 %, 1 %, and 2 %) were tested to determine the optimal formulation. The scaffolds were subjected to extensive physical, chemical, and mechanical evaluations using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), compressive stress tests, and measurements of density and porosity. The release profile of alendronate sodium, scaffold swelling behavior in water, bioactivity, and in vitro performance were thoroughly assessed. Cell viability was tested using the MTT assay, while alkaline phosphatase (ALP) activity and cell adhesion studies were performed to evaluate osteogenic potential. The results revealed that the GEL/HA/1 % HNT/AL nanocomposite scaffold exhibited excellent properties, including efficient drug release, optimal swelling rates, and enhanced bioactivity. The MTT assay confirmed high cell viability, and both ALP activity and cell adhesion studies indicated strong potential for bone cell differentiation and repair. Thus, the GEL/HA/1 % HNT/AL nanocomposite scaffold is a highly promising platform for bone tissue engineering.

Application of the EBSD Technique in the Study of Porosity and Permeability in Deformation Bands in Sandstone.

Deformation bands are common constituents of porous clastic fluid reservoirs. Various techniques have been used to study deformation band structure and the associated changes in porosity and permeability. However, the use of electron backscatter diffraction technique is limited. Thus, more information is needed regarding the crystallographic relationships between detrital crystals, which can significantly impact reservoir rock quality. We employ microscopic and microstructural investigation techniques to analyze the influence of cataclastic deformation bands on pore space. Porosity measurements of the Cretaceous Ilhas Group sandstone in NE Brazil, obtained through computerized microtomography, indicate that the undeformed domains exhibit a total porosity of up to 13%. In contrast, this porosity is slightly over 1% in the deformation bands. Scanning electron microscopy analyses revealed the presence of grain fragmentation and dissolution microstructures, along with cement-filling pre-existing pores. The electron backscatter diffraction analyses indicated extensive grain fragmentation and minimal contribution from intracrystalline plasticity as a deformation mechanism. However, the c axes of quartz crystals roughly align parallel to the orientation of the deformation band. In summary, we have confirmed and quantified the internal changes in a deformation band cluster, with grain size reduction and associated compaction as the main mechanism supported by quartz cementation.

Complementary testing and machine learning techniques for the characterization and prediction of middle Permian tight gas sandstone reservoir quality in the northeastern Ordos Basin, China

In this study, an integrated approach for diagenetic facies classification, reservoir quality analysis and quantitative wireline log prediction of tight gas sandstones (TGSs) is introduced utilizing a combination of fit-for-purpose complementary testing and machine learning techniques. The integrated approach is specialized for the middle Permian Shihezi Formation TGSs in the northeastern Ordos Basin, where operators often face significant drilling uncertainty and increased exploration risks due to low porosities and micro-Darcy range permeabilities. In this study, detrital compositions and diagenetic minerals and their pore type assemblages were analyzed using optical light microscopy, cathodoluminescence, standard scanning electron microscopy, and X-ray diffraction. Different types of diagenetic facies were delineated on this basis to capture the characteristic rock properties of the TGSs in the target formation. A combination of He porosity and permeability measurements, mercury intrusion capillary pressure and nuclear magnetic resonance data was used to analyze the mechanism of heterogeneous TGS reservoirs. We found that the type, size and proportion of pores considerably varied between diagenetic facies due to differences in the initial depositional attributes and subsequent diagenetic alterations; these differences affected the size, distribution and connectivity of the pore network and varied the reservoir quality. Five types of diagenetic facies were classified: (ⅰ) grain-coating facies, which have minimal ductile grains, chlorite coatings that inhibit quartz overgrowths, large intergranular pores that dominate the pore network, the best pore structure and the greatest reservoir quality; (ⅱ) quartz-cemented facies, which exhibit strong quartz overgrowths, intergranular porosity and a pore size decrease, resulting in the deterioration of the pore structure and reservoir quality; (ⅲ) mixed-cemented facies, in which the cementation of various authigenic minerals increases the micropores, resulting in a poor pore structure and reservoir quality; (ⅳ) carbonate-cemented facies and (ⅴ) tightly compacted facies, in which the intergranular pores are filled with carbonate cement and ductile grains; thus, the pore network mainly consists of micropores with small pore throat sizes, and the pore structure and reservoir quality are the worst. The grain-coating facies with the best reservoir properties are more likely to have high gas productivity and are the primary targets for exploration and development. The diagenetic facies were then translated into wireline log expressions (conventional and NMR logging). Finally, a wireline log quantitative prediction model of TGSs using convolutional neural network machine learning algorithms was established to successfully classify the different diagenetic facies.

Advancing Reservoir Evaluation: Machine Learning Approaches for Predicting Porosity Curves

Porosity assessment is a vital component for reservoir evaluation in the oil and gas sector, and with technological advancement, reliance on conventional methods has decreased. In this regard, this research aims to reduce reliance on well logging, purposing successive machine learning (ML) techniques for precise porosity measurement. So, this research examines the prediction of the porosity curves in the Sui main and Sui upper limestone reservoir, utilizing ML approaches such as an artificial neural networks (ANN) and fuzzy logic (FL). Thus, the input dataset of this research includes gamma ray (GR), neutron porosity (NPHI), density (RHOB), and sonic (DT) logs amongst five drilled wells located in the Qadirpur gas field. The ANN model was trained using the backpropagation algorithm. For the FL model, ten bins were utilized, and Gaussian-shaped membership functions were chosen for ideal correspondence with the geophysical log dataset. The closeness of fit (C-fit) values for the ANN ranged from 91% to 98%, while the FL model exhibited variability from 90% to 95% throughout the wells. In addition, a similar dataset was used to evaluate multiple linear regression (MLR) for comparative analysis. The ANN and FL models achieved robust performance as compared to MLR, with R2 values of 0.955 (FL) and 0.988 (ANN) compared to 0.94 (MLR). The outcomes indicate that FL and ANN exceed MLR in predicting the porosity curve. Moreover, the significant R2 values and lowest root mean square error (RMSE) values support the potency of these advanced approaches. This research emphasizes the authenticity of FL and ANN in predicting the porosity curve. Thus, these techniques not only enhance natural resource exploitation within the region but also hold broader potential for worldwide applications in reservoir assessment.

Porous gelatin-based phosphorylated scaffold: Microstructure, cell response and osteogenic differentiation of human adipose-derived mesenchymal stem cells

To repair the highly organized composite bone tissue, the design and development of biomimetic three-dimensional scaffolds is an active strategy. Here, we describe the fabrication route of a bioengineered gelatin-based scaffold for potential application in bone tissue engineering. First, phosphorus-containing polyurethane (PU–P) polymer was synthesized by polymerization starting from phosphorous polyol and methylene diisocyanate (DMI). Second, a gelatin/phosphorus-containing polyurethane (Gelatin/PU-P) scaffold was prepared by solution mixing, ultrasonication, and freeze-drying of gelatin and PU-P polymer. Next, prepared scaffold samples were characterized by FT-IR, SEM microscopy, porosity measurement, swelling, degradability, and mechanical tests. The scaffold with a porosity of about 78 % was achieved, and at the same time, it had good dimensional stability so that it only lost 43.61 % of its initial weight after 35 days immersing in PBS. Moreover, Gelatin/PU-P showed flexibility, large elongations at break (420 %) and high tensile strength (14 MPa). Finally, biological assessments revealed that the scaffold significantly supported the viability of Adipose-derived mesenchymal stem cells (ADMS). High ALP activity, enhancement in mineralization, and greater expression of osteogenic gene markers in cells grown on the Gelatin/PU-P confirmed the osteoinductivity of the scaffold. These findings suggested that Gelatin/PU-P can be used as a bioactive scaffold for bone tissue engineering.

Preparation, characterization and applications of polyethersulfone/bentonite clay composite for protein removal

In the current work, asymmetric polyethersulfone/bentonite clay nanocomposite (PES/BNT) membranes with differing clay dosages were successfully prepared by the phase inversion method aimed at protein separation. Means of characterization tools were harnessed to validate the fabrication process. The morphology and structure of membranes were examined by scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR) while additional surface properties such as pore size, porosity and hydrophilicity measurements were assessed. The permeability-selectivity trade-off of the membranes were assessed to probe the influence of additive content on the ultimate membrane functionality. The results indicated that best membrane performance was achieved with a BNT content of 0.225 g, resulting in enhanced dispersibility within the polymeric matrix. Besides, the inclusion of clay additive led to an increase in pore size ratio in the skin layer, further improving membrane permeability. The optimal membrane exhibited a permeate flux of 20.5 kg.m−2.h−1, while rejected 93 % of bovine serum albumin (BSA). Meanwhile, porosity, pore size and the contact angle measurements have recorded 71.8 %, 22.6 nm and 40.53°, respectively. These findings suggested that the PES/BNT membrane's permeation and separation characteristics, rendering them a viable option for a wide range of water and wastewater treatment applications.

Porosity–permeability characteristics and mineralization–alteration zones of the Maoping germanium-rich lead–zinc deposit in SW China

The Maoping superlarge germanium-rich lead–zinc deposit is a typical nonmagmatic hydrothermal deposit that is structurally controlled in the Sichuan–Yunnan–Guizhou lead–zinc polymetallic metallogenic area. The orebodies are distributed in several formations. This paper is based on large-scale alteration mapping combined with porosity and permeability measurements. We delineated the mineralization–alteration zones of different ore-bearing formations, explored the geological significance of porosity and permeability, and proposed prospecting directions. The research results indicate that during the mineralization period, the ore-forming metal fluids migrated from the deep part of the SSW region to the shallow part of the NNE region along the ore-guiding structure (Maoping Fault). Through the ore distribution structure, depressurization boiling occurred in the open space of the NE-trending interlayered sinistral compressive–torsional faults in several ore-bearing formations, resulting in fluid precipitation and the formation of different brecciated hot-melt dolomite lead–zinc mineralization zones. From the orebody to the wallrock, the C2w Formation and D3zg Formation are divided into four different mineralization–alteration zones. Tectonic activity affects the properties, migration, and precipitation of fluids, thereby controlling the alteration characteristics generated during fluid migration and thus changing the porosity and permeability. The porosity and permeability of strata on the NW flank of the anticline are greater than those of strata on the SE flank. On the NW flank, the greater the degree of mineralization–alteration is, the greater the porosity and permeability are, and the porosity of the orebody is lower than that during dolomitization. Finally, we believe that the NW flank of the anticline is an important area for prospecting. The pyrite + striped altered dolomite zone (Zones II–III) in the C2w limestone and the pyrite + strong dolomite zone (Zones II–III) in the D3zg dolomite are important prospecting indicators.

Mechanisms of alkali-activation of limestone: Reaction kinetics and influence of drying parameters

This paper focuses on the study of the reaction between limestone and sodium hydroxide solution. This reaction is used to produce alkali-activated mortars after curing and in the presence of unreactive siliceous sand. The kinetics of this reaction is investigated by semi-adiabatic calorimetry experiments. The formulation parameters are fixed but the curing parameters are tested: temperature (38 and 45°C) and time of drying (14, 25, 27 and 28 days). Their impact on reaction products (identified by FTIR and thermal analysis), on microstructure (SEM observations and porosity measurements) and on mechanical strength (flexural and compressive tests) are determined. The reaction was fast and a temperature drying was required to obtain stabilized hydration products in mortars. The products of the alkali-activation of limestone are double sodium/calcium carbonate (mainly pirssonite and with specific conditions of curing gaylussite) and calcium hydroxide. The microstructure and the proportions of reaction products, impacted by drying conditions, influence the mechanical strength of mortars. With an appropriate time (25 days) and temperature of drying (45°C), the compressive strength reached, after 28 days, almost 25 MPa.

Characterization of seismic-scale petrofacies variability in the Arbuckle Group using supervised machine learning: Wellington Field, Kansas

The Arbuckle Group in southern Kansas has been investigated for carbon geosequestration-related studies. In this study, we evaluated the seismic-scale petrophysically defined facies variability of the Arbuckle Group at the Wellington Field, Kansas, using quantitative seismic interpretation and a supervised Random Forest classification approach. We first defined three petrophysics-based rock types (petrofacies) from core-derived porosity and permeability measurements using the flow-zone indicator approach. Then, using the artificial neural network, we classified these petrofacies in noncored intervals. We observed that petrofacies 1 corresponds to medium and coarse-grained dolomitic packstone, wackestone, and dolomitic breccia with up to 8% porosity and D-scale permeability values. Whereas petrofacies 2 and 3 correspond to argillaceous and fine-grained micritic dolomites and dolomitic mudstones with lower permeability values for a given porosity, with respect to petrofacies 1. Using the common reflection-point gathers, we performed prestack seismic inversion and calculated various amplitude-variation-with-offset (AVO) attribute volumes. We used these elastic properties and AVO attribute volumes as input for estimating supervised seismic-scale 3D petrofacies and petrofacies probability volumes using the Random Forest algorithm. Results reveal the complex distribution of the petrofacies in the candidate injection and baffle zones in the study area, where petrofacies 1 is mainly prevalent within the lower and upper portions of the Arbuckle group, whereas petrofacies 2 and 3 are mainly present in the middle Arbuckle interval. The workflow we present through this study provides the spatial variability of facies distribution that is reflective of the actual lithology and petrophysical properties of the Arbuckle group in the study area with limited well control.

Paleosol-induced early dolomitization with U[sbnd]Pb age constraints and its implications for fluid pathways in ancient sandstone aquifers

In hydrogeology, a key challenge involves identifying patterns within ancient formations to forecast the distribution of fluid pathways and barriers to permeability, as well as comprehending the palaeohydrological system and its changes over time. This study addresses two main research inquiries concerning fluid flow: firstly, the influence of dolomitization induced by paleosols on flow characteristics, and secondly, the implications for fluid flow pattern distribution in continental sedimentary units. The objectives are pursued through: (1) meticulous, high-resolution measurements of porosity and permeability coupled with well-log data from an outcrop and two boreholes; (2) investigation of petrographic features of diagenetic minerals and their ages using the UPb geochronology system; and (3) an integration of these methodologies to grasp rock properties and fluid flow at a broader scale. Findings suggest that early dolomitization in continental sequences significantly affects fluid flow properties across the basin. The development of paleosols triggered early dolomitization, supported by UPb geochronology evidence. Subsequent groundwater migration along hydraulic gradients, influenced by fluctuations in the local aquifer's water table, facilitated the vertical distribution of dolomitization. Dolomitization occurred in residual pores resulting from initial mineral alteration, early lithifying the sediment and preventing mechanical compaction, thus preserving porosity. During migration events, fluids moved vertically along local faults and horizontally through the dolomitized layers of the formation, which likely remained porous at the time, leading to substantial silica mineralization.

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.

Quantifying the water saturation degree of cement-based materials by hydrogen nuclear magnetic resonance (1H NMR)

This study investigated the T2 spectrum of hydrogen nuclear magnetic resonance (1H NMR) signals in cement paste with water-to-cement ratios (w/c) of 0.2, 0.35, and 0.5 under three different saturation methods (natural soak, vacuum saturation, and vacuum saturation with high pressure). The saturation degree and pore structure of the cement paste under different saturation methods has been calculated through the linear relationship between water absorption and increment of NMR amplitude intensity. The results showed that the saturation degree of the cement paste increased progressively with the duration of saturation until it reached a state of equilibrium. It can increase saturation degree and reduce the saturation time by increasing the saturation pressure, and vacuum saturation with high pressure is necessary for cement paste with lower w/c. It is important to noted that conditions such as unsaturation, natural soak, and vacuum saturation may result in incomplete water saturation, leading to a partial loss of the 1H NMR signal amplitude intensity and underestimation of porosity measurements. Considering the duration of saturation and the degree of saturation, it is recommended a saturation duration of at least 4 h with a vacuum pressure of 8 MPa for cement paste with w/c ratio of 0.2 and 0.35. For cement paste with w/c of 0.5, a saturation duration of at least 0.5 h with a vacuum pressure of 8 MPa is suggested.

Leaching behavior and compressive strength in the immobilization of Cs-137 contaminated electric arc furnace dust via doping with activated carbon

This study evaluated the potential of an immobilization technique to inhibit the migration and dispersion of Cs-137 contaminated electric arc furnace dust (EAFD) into the environment, by investigating its compressive strength and leaching characteristics. The EAFD was employed to replace ordinary Portland cement (OPC) in varied ratios, ranging from 0 % to 50 % by weight. The replacement was done using various water-binder ratios of 0.35, 0.40, 0.45, and 0.50. Furthermore, the use of activated carbon (AC) has been shown to minimize radionuclide and heavy metal discharge related to its high porosity. AC was added at weight concentrations of 0.5 %, 1.0 %, 1.5 %, and 2.0 %. Compressive strength and leaching tests are used to assess the long-term stability of waste forms and the effectiveness of immobilizing radioactive wastes, which is beneficial for storing and disposing of radioactive waste. The compressive strength is affected by the amount of EAFD, water-to-binder ratios, the addition of AC, and the duration of curing. Measurements of specific surface area, pore size, pore volume, and porosity were also carried out under various conditions. The research results indicate that the addition of AC improves the compressive strength and decreases the release of Cs-137 and heavy metals from the specimen. The mixture of 45 % EAFD and 1.5 % AC is appropriate for efficiently immobilizing Cs-137 contaminated EAFD.

Diffusive Leakage of scCO2 in Shaly Caprocks: Effect of Geochemical Reactivity and Anisotropy

Summary Supercritical carbon dioxide (scCO2) trapping mechanisms within carbon geostorage (CGS) primarily hinge on the upper caprock system, with shales being favored for their fine-grained nature and geological abundance. Experimental assessments of CO2 reactivity in brine-saturated shales reveal microstructural changes, raising concerns about long-term CO2 leakage risks. Existing models of scCO2 transport through caprocks lack consideration for shale anisotropy. This study addresses these gaps by investigating the diffusive properties and propagation of geochemical reactivity in shaly caprocks, accounting for anisotropy. Horizontal and vertical core samples from three shale formations with varying petrophysical characteristics underwent mineralogical, total organic carbon (TOC), porosity, and velocity measurements. scCO2 treatment for up to 3 weeks at 150°F and 3,000 psi was conducted. The propagation of geochemical reactivity was monitored by multiple surface X-ray fluorescence (XRF) measurements and fine polishing. A nuclear magnetic resonance (NMR)-based H2O-D2O fluid exchange protocol was used to quantify effective diffusivities and tortuosities parallel and perpendicular to bedding. Results indicate preferential surface reactivity toward carbonate minerals; however, the apparent reaction diffusivity of the shaly caprock is notably slow (~10−15 m2/s). This aligns with previous experimental and reactive transport modeling studies, emphasizing long timescales for carbonate dissolution reactions to influence shale caprock properties. Shale-effective diffusivities display anisotropy increasing with clay content, where diffusivities parallel to bedding exceed those perpendicular by at least three times. Faster horizontal diffusion in shaly confining zones should be considered when estimating diffusive leakage along faults penetrating these zones, a significant risk in CGS. Post-scCO2 treatment, diffusivity changes vary among samples, increasing within the same order of magnitude in the clay-rich sample. Nonsteady-state modeling of scCO2 diffusion suggests limited caprock penetration over 100 years, with a minimal increase from 5 m to 7 m post-scCO2 treatment for the clay-rich sample. This study extends existing literature observations on the slow molecular diffusion of scCO2 within shaly caprocks, integrating the roles of geochemical reactions and shale anisotropy under the examined conditions.

The synergistic effect of recycled glass fiber reinforced plastic and silica fume on cement mortar properties

In recent years, there has been a significant increase in the generation of glass fiber-reinforced plastic (GFRP) waste. Traditional disposal methods have led to the wastage of resources and elevated carbon emission rates. Therefore, recycled glass fiber reinforced plastic powder was utilized to synergistically substitute a portion of the cement with silica fume, aiming to produce green cementitious composites. The study focuses on crucial properties such as strength, drying shrinkage, and fluidity. XRD, TG/DTG, and FT-IR analyses were conducted to clarify the hydration process of the composites, while MIP and water porosity measurements assessed the modifications in pore structure across various sample groups. The results demonstrate that the compressive strength of the new composite substantially increases by approximately 40 %, while cement consumption decreases by 30 %. This study presents a pioneering utilization of recycled glass fiber-reinforced plastic (RGFRP) and an innovative method for producing eco-friendly cementitious composites.

Dietary intervention rescues a bone porosity phenotype in a murine model of Neurofibromatosis Type 1 (NF1).

Neurofibromatosis type 1 (NF1) is a complex genetic disorder that affects a range of tissues including muscle and bone. Recent preclinical and clinical studies have shown that Nf1 deficiency in muscle causes metabolic changes resulting in intramyocellular lipid accumulation and muscle weakness. These can be subsequently rescued by dietary interventions aimed at modulating lipid availability and metabolism. It was speculated that the modified diet may rescue defects in cortical bone as NF1 deficiency has been reported to affect genes involved with lipid metabolism. Bone specimens were analyzed from wild type control mice as well as Nf1Prx1-/- (limb-targeted Nf1 knockout mice) fed standard chow versus a range of modified chows hypothesized to influence lipid metabolism. Mice were fed from 4 weeks to 12 weeks of age. MicroCT analysis was performed on the cortical bone to examine standard parameters (bone volume, tissue mineral density, cortical thickness) and specific porosity measures (closed pores corresponding to osteocyte lacunae, and larger open pores). Nf1Prx1-/- bones were found to have inferior bone properties to wild type bones, with a 4-fold increase in the porosity attributed to open pores. These measures were rescued by dietary interventions including a L-carnitine + medium-chain fatty acid supplemented chow previously shown to improve muscle histology function. Histological staining visualized these changes in bone porosity. These data support the concept that lipid metabolism may have a mechanistic impact on bone porosity and quality in NF1.

Optimizing Micro-CT Resolution for Geothermal Reservoir Characterization in the Pannonian Basin

In the context of global efforts to transition toward renewable energy and reduce greenhouse gas emissions, geothermal energy is increasingly recognized as a viable and sustainable option. This paper presents a comprehensive assessment derived from a subset of a larger sample collection within the Dunántúli Group of the Pannonian Basin, Hungary, focusing on optimizing micro-computed tomography (µ-CT) resolution for analyzing pore structures in sandstone formations. By categorizing samples based on geological properties and selecting representatives from each group, the study integrates helium porosity and gas permeability measurements with µ-CT imaging at various resolutions (5 µm, 2 µm, and 1 µm). The findings reveal that µ-CT resolution significantly affects the discernibility and characterization of pore structures. Finer resolutions (2 µm and 1 µm) effectively uncovered interconnected pore networks in medium- to coarse-grained sandstones, suggesting favorable properties for geothermal applications. In contrast, fine-grained samples showed limitations in geothermal applicability at higher resolutions due to their compact nature and minimal pore connectivity, which could not be confidently imaged at 1 µm. Additionally, this study acknowledges the challenges in delineating the boundaries within the Dunántúli Group formations, which adds a layer of complexity to the characterization process. The research highlights the importance of aligning µ-CT findings with geological backgrounds and laboratory measurements for accurate pore structure interpretation in heterogeneous formations. By contributing vital petrophysical data for the Dunántúli Group and the Pannonian Basin, this study provides key insights for selecting appropriate µ-CT imaging resolutions to advance sustainable geothermal energy strategies in the region. The outcomes of this research form the basis for future studies aimed at developing experimental setups to investigate physical clogging and enhance geothermal exploitation methods, crucial for the sustainable development of geothermal resources in the Pannonian Basin.

Development of low-cost clayey ceramic filtering membrane with controllable porosity and high mechanical strength

The conventional approach to generate pores in ceramic membranes involves the incorporation of a pore-forming element. However, this method tends to diminish the mechanical properties of the membranes and poses challenges in effectively regulating both pore size and membrane porosity. In this work, low-cost ceramic filtering membranes with enhanced mechanical strength have been successfully prepared mainly from abundant clays and without the need for pore-forming agents. The Porosity and pore size were controlled by adding a finely-grained clay (d90 = 22 μm) by-product to coarse clay (d90 = 50 μm) within a specified range of 33–66 wt%. The microstructure evolution of prepared membranes was examined by XRF, FTIR, XRD, SEM, and DTA-TGA analysis, while the technological properties were evaluated by permeability, porosity, density, and mechanical measurements. The findings indicated that the increase in the amount of finely grained clay mixed with coarse clay and the sintering temperature had a synergistic effect on the porosity and pore size of the obtained membranes. The incorporation of finely-grained clays, accompanied by an elevation in sintering temperature, led to a reduction in porosity from 31.3 ± 0.7 % to 6.2 ± 0.5 % and pore size, along with the crystallization of the α-mullite (12 %) and anorthite (30 %) phase with a quartz phase and an improvement in mechanical strength reaching up to 251 ± 3 MPa. A formulation comprising 33 wt% of finely-grained clay by-products and 67 wt% of coarse clay, sintered at 1000 °C, emerged as a promising ultrafiltering membrane with enhanced mechanical strength reaching 120 ± 1 MPa, and a permeability of 1000 L/h.m2 at 1 bar.

Prediction of in-vitro dissolution and tablet hardness from optical porosity measurements

Advanced manufacturing technologies such as continuous processing require fast information on the quality of intermediates and products. Process analytical technologies (PAT) to monitor many critical quality attributes (CQAs) have been developed and successfully implemented in pharmaceutical industry. However, there are some CQAs, which still have to be measured off-line with significant effort due to the lack of suitable PAT sensors. Two prominent examples are the in-vitro dissolution and the tablet hardness. Both are obtained via destructive measurement, and the dissolution is tedious and time-consuming to determine. In this study, these two CQAs were predicted via correlation with the optical porosity of tablets. The optical porosity was measured via a novel combination of gas in scattering media absorption spectroscopy (GASMAS) and photon time of flight spectroscopy (pTOFS) with a SpectraPore instrument. The approach was tested in a continuous tableting line and showed promising results in predicting the amount of drug released after specific dissolution times as well as the tablet hardness. This indicates that the measurement of optical porosity can support control strategies within the real-time release testing (RTRT) concept.