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Improving proton transfer is vital for electrocatalysis with porous materials. Although several strategies are reported to assist proton transfer in channels, few studies are dedicated to improving proton transfer at the local environments of active sites in porous materials. Herein, we report on new Co‐corrole‐based porous organic polymers (POPs) with improved proton transfer for electrocatalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By tuning the pore sizes and installing proton relays at Co corrole sites, we designed and synthesized POP‐2‐OH with improved proton transfer both in channels and at local Co active sites. This POP shows remarkable activity for both electrocatalytic ORR with E1/2=0.91 V vs RHE and OER with η10=255 mV. Therefore, this work is significant to present a strategy to improve active site local proton transfer in porous materials and highlight the key role of such structural functionalization in boosting oxygen electrocatalysis. [ABSTRACT FROM AUTHOR]

The separator membrane is one of the four key materials of a lithium-ion battery, and the size of the separator membrane pores plays an important role on the internal resistance and safety of the battery. In this study, firstly, the relationship between the average pore size and the pore center to center distance with different porosity ratios in the separator membrane was analyzed with statistical theory. Then, a mathematical model was established to predict the probability of intersections and merging of the pores. In the end, the probability of intersections of pores with different porosity ratios were calculated and simulated; the differences between the results obtained from the two ways were 1.16%, 1.47% and 4.16%, when the porosity ratios were 21.36%, 40.16% and 53.34%, respectively, which indicated that the prediction model had good accuracy. [ABSTRACT FROM AUTHOR]

Rigid polyurethane foam is a widely used insulation material in various industrial fields. Enhancing its insulating performance often involves controlling pore size to reduce radiative conductivity and, in some cases, decrease gas thermal conductivity through the Knudsen effect. While numerous studies have addressed reducing the pore size of thermoplastic polymer foam to the nano-scale, limited research has focused on rigid polyurethane foam. Although some studies have shown that pore size changes with the addition of nucleating agents, a comprehensive understanding of the mechanisms governing pore size remains elusive. Therefore, this study investigates the factors determining the pore size of rigid polyurethane foam. Our findings confirm that the size of air bubbles formed during the blending of prepolymers has the most significant impact on pore size. Furthermore, we demonstrate that regulating the size of air bubbles before the urethane reaction allows for control over the final pore size. Experimental details substantiating these findings are presented. [ABSTRACT FROM AUTHOR]

The coalification process significantly influences the composition of coal material and the development of pore size, ultimately affecting the adsorption capacity of coal seams and the extraction of coalbed methane. This project aimed to assess the pore structure and gas adsorption capacity of coal samples from nine key sedimentary basins in China. The N 2 test results revealed that during the initial stage of coalification, micropore, transition pore, and mesopore dominate in order of magnitude. In the subsequent coalification stages, the development of mesopore is most significant during the second jump, while the transition pore becomes more prominent in the third jump. Additionally, the findings from nuclear magnetic resonance tests indicate that the proportion of adsorbed pore demonstrates a decreasing-then-increasing trend throughout the coalification process. The first and second coalification jumps primarily contribute to the development of adsorption pore and seepage pore, whereas the third jump mainly focuses on adsorption pore development. The gas adsorption capacity is influenced by various factors such as pore structure, material composition, and chemical structure. During the first coalification jump, gas adsorption mainly occurs in the adsorption pore. In the second jump, medium gas adsorption capacity is achieved due to the combined effects of enhanced adsorption pore development and reduced moisture and ash content. Finally, the third coalification jump exhibits highly developed adsorption pores, the lowest moisture and ash levels, and a sufficient aromatic structure in the chemical composition, resulting in high adsorption capacity. These findings contribute to a deeper understanding of the variations in coalbed methane enrichment across different basins in China, with coalification playing a crucial controlling role. • Three key stages in coal pore evolution identified. • Pore size distribution during coal thermal evolution in key basins studied. • Gas adsorption capacity of coal during coalification jumps studied. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) ceramic membranes are highly sought-after for their exceptional properties including high temperature resistance, corrosion resistance, good hydrophilicity, high flux, and high mechanical strength. However, achieving stable regulation of high solid content SiC slurries for membrane preparation remains a significant challenge. This study presents a novel approach to stabilize the dispersion of high solid content SiC slurries by controlling parameters such as solid content, pH, ball milling time and spray coating parameters. Furthermore, the impact of different milling durations on SiC particle size and membrane performance is systematically investigated, establishing, for the first time, a direct correlation between milling time and particle size. The investigations reveal that prolonged ball milling, specifically 18 h, results in a notable reduction in membrane pore size by approximately 40 %, accompanied by a remarkable enhancement in retention performance, as evidenced by a substantial increase in the average retention rate for 500 nm fluorescent microspheres from 54.61 % to 98.89 %. This study not only offers a practical method for the stable preparation of ceramic slurries, but also provide important reference for membrane morphology control and pore size regulation. These insights hold significant promise for advancing SiC membrane technology in applications such as wastewater treatment and resource recovery. [ABSTRACT FROM AUTHOR]

As a non-renewable resource, oil faces increasing demand, and the remaining oil recovery rates in existing oil fields still require improvement. The primary objective of this study is to investigate the impact of pore structure parameters on the distribution and recovery of residual oil after polymer flooding by constructing a digital pore network model. Using this model, the study visualizes the post-flooding state of the model with 3DMAX-9.0 software and employs a range of simulation methods, including a detailed analysis of the pore size, coordination number, pore–throat ratio, and wettability, to quantitatively assess how these parameters affect the residual oil distribution and recovery. The research shows that the change in the distribution of pore sizes leads to a decrease in cluster-shaped residual oil and an increase in columnar residual oil. An increase in the coordination number increases the core permeability and reduces the residual oil; for example, when the coordination number increases from 4.3 to 6, the polymer flooding recovery rate increases from 24.57% to 30.44%. An increase in the pore–throat ratio reduces the permeability and causes more residual oil to remain in the throat; for example, when the pore–throat ratio increases from 3.2 to 6.3, the total recovery rate decreases from 74.34% to 63.72%. When the wettability changes from oil-wet to water-wet, the type of residual oil gradually changes from the difficult-to-drive-out columnar and film-shaped to the more easily recoverable cluster-shaped; for example, when the proportion of water-wet throats increases from 0.1:0.9 to 0.6:0.4, the water flooding recovery rate increases from 35.63% to 51.35%. Both qualitative and quantitative results suggest that the digital pore network model developed in this study effectively predicts the residual oil distribution under different pore structures and provides a crucial basis for optimizing residual oil recovery strategies. [ABSTRACT FROM AUTHOR]

Porous silica particles have shown great potential application as reinforcing fillers in the field of dentistry due to their ability to construct the micromechanical interlocking effect at filler-matrix interface. However, how to accurately regulate the pore structure, especially the pore size, to increase the degree of the micromechanical interlocking and the performance of materials remains a challenge. Herein, we have proposed a facile self-assembly process to synthesize dendritic porous silica with tunable pore sizes (DPS-x) by adjusting the chain-length of the alcohols in the microemulsion. The mechanism of nucleation-growth is further put forward. The results indicate that the pore size of DPS-x indeed affects the mechanical property of composites, where the DPS-pen particles with intermediate pore size are chosen as the optimal reinforcing fillers. The bimodal and multimodal filler formulations are further established to address the loading limitation of unimodal DPS-pen (46 wt%). In virtue of the close-packed structure of identical spheres, the particle sizes of secondary silica embedded into the maximally loaded bimodal D3S7 composite (DPS-pen:Si430 = 30:70, wt/wt) are theoretically calculated without trials. Among all formulations, the developed multimodal D3S7+Si178+Si90 filler exhibits superior mechanical properties, the lowest shrinkage, and high polymerization conversion for dental composites, along with satisfied waster sorption and solubility, and good biocompatibility in vitro and in vivo, which are comparable to commercial composite Z350 XT (3M, USA). These DPS-x particles and their multimodal fillers can also be applied to other polymer-based biomaterials. [ABSTRACT FROM AUTHOR]

The circular economy transition encompasses the identification of various available and sustainable materials to replace traditional binders in the construction industry. The utilization of water sediments represents this point as a beneficial action that may provide synergy in terms of waste reduction and replacement of energy-intensive materials. To explore the potential of water sediments, this study contemplated the characterization of water sediments as precursors for the design of alkali-activated materials (AAMs). The experimental approach was based on the detailed characterization of raw materials' chemical, mineralogical, and basic material properties and the assessment of the designed AAM paste and mortar samples. The results achieved revealed the capability of low amorphous water sediments to form dense structures with favorable mechanical performance, reaching up to 36.8 MPa in compressive strength. The microstructural and water sorption characteristics point to the applicability of such materials in the building practice and, thus, the valorization of water sediments into valuable material. [ABSTRACT FROM AUTHOR]

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There is an increasing need for compact low-cost NMR apparatus that can be used on the laboratory bench and in the field. There are four main usage variants of usage: (a) time-domain apparatus, particularly for physical measurements; (b) frequency-domain apparatus, particularly for chemical analysis, (c) NMR Cryoporometry apparatus for measuring pore-size distributions; and (d) MRI apparatus for imaging. For all of these, variable temperature capability may be vital. We have developed compact low-cost apparatus targeted at these applications. We discuss a hand-held NMR Spectrometer, and three different holdable NMR magnets, with sufficiently large internal bores for the Lab-Tools compact Peltier thermo-electric cooled variable-temperature probes. Currently, the NMR Spectrometer is very suitable for (a) NMR time-domain relaxation and (c) NMR Cryoporometry. With a suitable high-homogeneity magnet, it is also appropriate for simple use (b), spectral analysis, or, with a suitable gradient set, (d) MRI. Together, the NMR Spectrometer, one of the NMR variable-temperature probes, and any of these NMR magnets make excellent NMR Cryoporometers, as demonstrated by this paper and previously published research. Equally, they make versatile general-purpose variable-temperature NMR systems for materials science. [ABSTRACT FROM AUTHOR]

There is an increasing need for compact low-cost NMR apparatus that can be used on the laboratory bench and in the field. There are four main usage variants of usage: (a) time-domain apparatus, particularly for physical measurements; (b) frequency-domain apparatus, particularly for chemical analysis, (c) NMR Cryoporometry apparatus for measuring pore-size distributions; and (d) MRI apparatus for imaging. For all of these, variable temperature capability may be vital. We have developed compact low-cost apparatus targeted at these applications. We discuss a hand-held NMR Spectrometer, and three different holdable NMR magnets, with sufficiently large internal bores for the Lab-Tools compact Peltier thermo-electric cooled variable-temperature probes. Currently, the NMR Spectrometer is very suitable for (a) NMR time-domain relaxation and (c) NMR Cryoporometry. With a suitable high-homogeneity magnet, it is also appropriate for simple use (b), spectral analysis, or, with a suitable gradient set, (d) MRI. Together, the NMR Spectrometer, one of the NMR variable-temperature probes, and any of these NMR magnets make excellent NMR Cryoporometers, as demonstrated by this paper and previously published research. Equally, they make versatile general-purpose variable-temperature NMR systems for materials science.

Abstract The volume-sensitive outwardly rectifying or volume-regulated anion channel, VSOR/VRAC, which was discovered in 1988, is expressed in most vertebrate cell types, and is essentially involved in cell volume regulation after swelling and in the induction of cell death. This series of review articles describes what is already known and what remains to be uncovered about the functional and molecular properties as well as the physiological and pathophysiological roles of VSOR/VRAC. This Part 2 review article describes, from the physiological and pathophysiological standpoints, first the pivotal roles of VSOR/VRAC in the release of autocrine/paracrine organic signal molecules, such as glutamate, ATP, glutathione, cGAMP, and itaconate, as well as second the swelling-independent and -dependent activation mechanisms of VSOR/VRAC. Since the pore size of VSOR/VRAC has now well been evaluated by electrophysiological and 3D-structural methods, the signal-releasing activity of VSOR/VRAC is here discussed by comparing the molecular sizes of these organic signals to the channel pore size. Swelling-independent activation mechanisms include a physicochemical one caused by the reduction of intracellular ionic strength and a biochemical one caused by oxidation due to stimulation by receptor agonists or apoptosis inducers. Because some organic substances released via VSOR/VRAC upon cell swelling can trigger or augment VSOR/VRAC activation in an autocrine fashion, swelling-dependent activation mechanisms are to be divided into two phases: the first phase induced by cell swelling per se and the second phase caused by receptor stimulation by released organic signals.

Abstract This research delved into the influence of mesoporous silica’s surface charge density on the adsorption of Cu2+. The synthesis of mesoporous silica employed the hydrothermal method, with pore size controlled by varying the length of trimethylammonium bromide (CnTAB, n = 12, 14, 16) chains. Gas adsorption techniques and transmission electron microscopy characterized the mesoporous silica structure. Surface charge densities of the mesoporous silica were determined through potentiometric titration, while surface hydroxyl densities were assessed using the thermogravimetric method. Subsequently, batch adsorption experiments were conducted to study the adsorption of Cu2+ in mesoporous silica, and the process was comprehensively analyzed using Atomic absorption spectrometry (AAS), Fourier transform infrared (FTIR), and L3 edge X-ray absorption near edge structure (XANES). The research findings suggest a positive correlation between the pore size of mesoporous silica, its surface charge density, and the adsorption capacity for Cu2+. More specifically, as the pore size increases within the 3–4.1 nm range, the surface charge density and the adsorption capacity for Cu2+ also increase. Our findings provide valuable insights into the relationship between the physicochemical properties of mesoporous silica and the adsorption behavior of Cu2+, offering potential applications in areas such as environmental remediation and catalysis.

In this work, the deformation behavior of porous ceramics ZrO2–5.5 wt.% Y2O3 with different morphology of the pore space under axial quasi-static compression is studied by the digital image correlation (DIC) method. Two stages of the deformation behavior of the ceramics have been identified, namely, the controlled accumulation of microcracks and the formation of block structures. It has been found that an increase in the average pore size leads to a decrease in the tensile strength, a decrease in the effective elasticity modulus, and an increase in the ultimate deformation, while the nature of the deformation macrolocalization changes from ordered to chaotic one. It is shown that the rate of accumulation of local deformations in the central part of the deformable sample with a pore size of 68 μm is several times higher than in the sample with a pore size of 29 μm. [ABSTRACT FROM AUTHOR]

Relative permeability is a key parameter for characterizing the multiphase flow dynamics in porous media at macroscopic scale while it can be significantly impacted by wettability. Recently, it has been reported in microfluidic experiments that wettability is dependent on the pore size (Van Rooijen et al., 2022). To investigate the effect of pore‐size‐dependent wettability on relative permeability, we propose a theoretical framework informed by digital core samples to quantify the deviation of relative permeability curves due to wettability change. We find that the significance of impact is highly dependent on two factors: (i) the function between contact angle and pore size (ii) overall pore size distribution. Under linear function, this impact can be significant for tight porous media with a maximum deviation of 1,000%. Plain Language Summary: Relative permeability is an important feature for multiphase flow at the reservoir scale. It can be highly dependent on wettability, which is an interfacial property at the pore scale. Recent experimental evidence suggests that wettability is dependent on the pore size, but the impact of the pore‐size‐dependent wettability on relative permeability still remains unknown. In this study, we propose a theoretical model to investigate the effect of pore‐size‐dependent wettability on relative permeability. The pore size distribution is informed by the pore images. We find that the impact can be significant for low‐permeability porous media under certain conditions. The results imply that this effect is not always neglible when modeling two‐phase flow. Key Points: A theoretical framework is proposed to quantify the impact of pore‐size dependent wettability on relative permeabilityThe maximum impact on relative permeability can be as significant as 1,000% [ABSTRACT FROM AUTHOR]

Measurements of the thermal conductivity were performed as a function of gas pressure from 10–1 hPa up to 105 hPa on several bimodal silica xerogels. The xerogels exhibit a mesopore and a macropore phase. The measurements were done using a hot-wire apparatus, which can do automated, gas pressure-dependent measurements of the thermal conductivity from 10–3 up to 105 hPa. Results were fitted with a bimodal gas pressure-dependent thermal conductivity model to gain information on the thermal conductivity of the materials, its various contributions and on structural parameters such as the two main pore sizes, the macro- and mesoporosities. The pore sizes and porosities were compared to values gained from mercury porosimetry and nitrogen adsorption measurements. The porosities from the thermal conductivity measurements are in very good agreement to the other measuring methods. The macropore sizes from the thermal conductivity measurements are mostly in agreement within the given uncertainty range and the mesopore sizes show a good estimate of the order of magnitude of the pores. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in New & Renewable Energy is the property of Editorial Office of Advances in New & Renewable Energy and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Scaffold porosity is a critical factor in replicating the complex in vivo microenvironment, directly influencing cellular interactions, migration, nutrient transfer, vascularization, and the formation of functional tissues. For optimal tissue formation, scaffold design must account for various parameters, including material composition, morphology, mechanical properties, and cellular compatibility. This review highlights the importance of interconnected porosity and pore size, emphasizing their impact on cellular behavior and tissue formation across several tissue engineering domains, such as skin, bone, cardiovascular, and lung tissues. Specific pore size ranges enhance scaffold functionality for different tissues: small pores (∼1–2 µm) aid epidermal cell attachment in skin regeneration, moderate pores (∼2–12 µm) support dermal migration, and larger pores (∼40–100 µm) facilitate vascular structures. For bone tissue engineering, multi-layered scaffolds with smaller pores (50–100 µm) foster cell attachment, while larger pores (200–400 µm) enhance nutrient diffusion and angiogenesis. Cardiovascular and lung tissues benefit from moderate pore sizes (∼25–60 µm) to balance cell integration and nutrient diffusion. By addressing critical design challenges and optimizing pore size distributions, this review provides insights into scaffold innovations, ultimately advancing tissue regeneration strategies.

Abstract The compressive strength is very important for petroleum and other engineering studies. However, the effect of pore size and fluid distribution on the rock’s strength is not fully understood. We developed comprehensive research to study the controlling factors of the compressive strength based on low field nuclear magnetic resonance (NMR) measurements and pseudo-triaxial compression test for tight sandstones. The relationship between the compressive strength and the NMR obtained parameters are investigated completely, aiming for a better estimation of the compressive strength using the NMR data. The result shows that the rock’s strength is strongly controlled by the pore size distribution and the fluid existing state. Generally, the compressive strength is negatively correlated with the average transversal relaxation time, the movable water saturation, and the porosity, but positively correlated with the irreducible water saturation. The result reveals that the rock with larger pore radius and higher percentage of movable fluid is easier to reach the failure state. Further, the precision of the empirical model by multiple regression of the geometric mean of the relaxation time and the porosity is greatly improved compared with the model established by the brittle minerals, which is potentially to be use for geophysical prospecting when the NMR logging data is available.

Objective： To improve the adsorption of genistein by zirconium-based metal-organic frameworks （MOFs） with triangle aromatic ligands. Methods： Two MOFs （MOF-808 and PCN-777） containing different sizes of triangle aromatic ligands were synthesized by hydrothermal method for adsorption of genistein. The synthesis of MOFs was determined by a series of characterization methods, and the adsorption performance was compared with that of a linear binary carboxylic acid ligand-constructed MOF （UiO-66）, to evaluate the effects of pore characteristics, hydrophobicity changes, and other factors on the adsorption performance, and to explore the adsorption mechanism by XPS analysis. Results： Compared with linear ligand-constructed UiO-66, the pore sizes of triangular aromatic ligand-constructed MOFs （MOF-808, and PCN-777） increased from 0.65 nm to 1.81 nm and 3.55 nm, respectively, and the water contact angles increased from 47.91° to 110.68° and 128.23°, respectively. The adsorption capacity and adsorption efficiency of genistein in linear ligand-constructed UiO-66 was 40.08 mg/g and 39.98%, respectively, while the adsorption capacity and adsorption efficiency of genistein in MOFs constructed by triangular aromatic ligand （MOF-808, PCN-777） was increased to 61.80 mg/g, 81.75 mg/g and 61.63%, 81.52% respectively. Conclusion： Metal-organic frameworks （MOFs） can be used for the adsorption and enrichment of genistein. Compared with linear ligands, the introduction of triangular aromatic ligands with different sizes changes the pore size and hydrophobicity of MOFs, enhances the internal accessibility of MOFs, and provides more adsorption sites, which improves the adsorption effect of genistein. The adsorption mechanism of genistein in PCN-777 is based on the synergistic combination of metal-chelating interactions, π-π interactions, and hydrophobic interactions.

Exudate absorption is a key parameter for proper wound dressing performance. Unlike standardized tests that consider exudate viscosity close to that of water, patients' exudates vary greatly in composition and, therefore, viscosity. This work aimed to investigate the effects of exudate viscosity and pore size of hydrogel-like dressings on the exudate absorption rate to establish rational criteria for the design of dressings that can meet the personalized needs of wound treatment. Computer-aided design (CAD) was used for Digital Light Processing (DLP) 3D printing of hydrogels with 0%, 30% and 60% porosity. The hydrogels were characterized in detail, and the absorption of two simulated exudate fluids (SEFs) was video-recorded. The same CAD files were used to develop in silico models to simulate exudate uptake rate. Both in vitro data and in silico modeling revealed that low-viscosity SEF penetrates faster through relatively small hydrogel pores (approx. 400 μm) compared to larger pores (approx. 1100 μm) due to capillary forces. However, in vitro vertical uptake took longer than when simulated using CAD design due to lateral fluid absorption through the pore walls in the hydrogel bulk. Distortions of hydrogel channels (micro-CT images) and lateral fluid absorption should be both considered for in silico simulation of SEF penetration. Overall, the results evidenced that porous hydrogel dressings allow rapid penetration (within a few seconds) and hosting of exudates, especially for pore size

Conventional synthetic vascular grafts are associated with significant failure rates due to their mismatched mechanical properties with the native vessel and poor regenerative potential. Though different tissue engineering approaches have been used to improve the biocompatibility of synthetic vascular grafts, it is still crucial to develop a new generation of synthetic grafts that can match the dynamics of native vessel and direct the host response to achieve robust vascular regeneration. The size of pores within implanted biomaterials has shown significant effects on macrophage polarization, which has been further confirmed as necessary for efficient vascular formation and remodeling. Here, we developed biodegradable, autoclavable synthetic vascular grafts from a new polyurethane elastomer and tailored the grafts' interconnected pore sizes to promote macrophage populations with a pro-regenerative phenotype and improve vascular regeneration and patency rate. The synthetic vascular grafts showed similar mechanical properties to native blood vessels, encouraged macrophage populations with varying M2 to M1 phenotypic expression, and maintained patency and vascular regeneration in a one-month rat carotid interposition model and in a four-month rat aortic interposition model. This innovative bioactive synthetic vascular graft holds promise to treat clinical vascular diseases.

In this study, we aimed to develop a model for computing direct contact membrane distillation (DCMD) performance, taking into account capillary pressure effects at the liquid--gas interface within membrane pores. We developed a simulation model to investigate how factors such as pore radius, feed/permeate temperature, pressure, and contact angle influenced the distance of liquid intrusion into the pore, the weight flow rate in a single pore, and the temperature at the liquid--gas interface. The model predicted that the permeation rate would decrease with an increase in the feed pressurewhen the permeate pressure was kept constant and also when the pressure difference between the feed and permeate was kept constant. It also predicted that the permeation rate would increase with an increase in the permeate pressure when the feed pressure was kept constant. The model also indicated that partial pore wetting would be enhanced with an increase in feed pressure when the pore size was as large as 1 μm but would diminish when the pore size was as small as 0.1 μm. According to the model, partial pore wetting diminished with a decrease in the permeate pressure. The model's predictions were in line with the trends observed in the experimental DCMD flux data by many authors, particularly those regarding the effects of feed and permeate temperature and the effect of contact angle. The model's predictions were compared with the experimental data recorded in the literature, validating the model's accuracy. [ABSTRACT FROM AUTHOR]

In this work, we have designed unique poly(lactic acid- co -glycolic acid)- b -poly(ethylene oxide)- b -poly(propylene oxide)- b -poly(ethylene oxide)- b -poly(lactic acid- co -glycolic acid) pentablock copolymers using Pluronic F68 and F108 triblock copolymers as macroinitiators. The poly(lactic acid- co -glycolic acid) (PLGA) blocks were attached as glycolide and lactide monomers at the both ends of each F68 and F108 triblock copolymer. The molecular weights and the block fractions were confirmed by gel permeation chromatography (GPC) and proton nuclear magnetic resonance (1H NMR) for the four kinds of pentablock copolymers. Using these pentablock copolymers as templates, we synthesized mesoporous ethane-silicas as well as silicas by the evaporation-induced self-assembly (EISA) method. 1,2-bis(triethoxysily)ethane (BTEE) were used as an organosilica precursor. The mesoporous ethane-silica samples were characterized using synchrotron small angle X-ray scattering (SAXS), nitrogen sorption experiments, transmission electron microscopy (TEM), and solid-state 29Si CP-MAS NMR. Based on the experimental results, it was confirmed that the porosity and pore diameter can be varied with the PLGA weight fraction of the pentablock copolymer. It is due to the PLGA block in polymer forming the hydrophobic domain in micelles, which leads to the formation of increased pore size over 20 nm without any additive pore expander. In addition, it seems that as the organosilica precursor increases, the association number of block copolymers forming one micelle decreases, resulting in a decrease in pore size. In summary, the polymer template plays a vital part in tuning the structure of the mesoporous ethane-silica samples. Thus, the development of synthetic method of mesoporous organosilica materials using polymer templates with different topology is still challenging and can endow the unique structure and property for mesoporous organosilica for future applications. [ABSTRACT FROM AUTHOR]

Solar desalination, harvesting solar energy to purify seawater, has received considerable attention due to water scarcity problems caused by climate change and human activity. In this study, we investigated a membrane desalination method that collects vaporized water from the surface of a sun-lit porous medium floating on salt water. To maximize the water evaporation rate at the membrane surface, several effective photothermal converting materials were coated on the membrane. In addition, to amplify the water transport to the sun-lit surface, the pore size of the porous medium also was controlled by filtering sugar particles by size. We found that the evaporation rate increased as the reflectivity of the coating materials decreased, and demonstrate the optimized pore size, leading to improved evaporation at the three-phase interface by controlling the size of the pores. The water transport is caused by the porous medium resulted from competition between capillary and viscous forces; thus, the optimal pore size for maximum water transport and evaporation rate is discussed. The finding of this study provide insight into optimizing the design of the membrane's structure and coating materials to maximize the evaporation rate in solar desalination. [ABSTRACT FROM AUTHOR]

Propylene (C3H6) is a crucial olefin raw material used in the production of polypropylene, which is the world's second-most produced synthetic plastic. Separating propylene from propane (C3H8) is an important and significant challenge for industry due to the similar molecular sizes and physical properties of these gases. At present, the usual method for this separation is energy-intensive cryogenic distillation, which has low efficiency and high energy consumption. Therefore, an energy-efficient alternative way is in an urgent demand. Metal-organic frameworks (MOFs) are promising candidates for propylene/propane separation, thanks to the well-defined, designable, modifiable, and flexible structures. This review provides a summary of a recent development of MOFs that are able to discriminate between propylene and propane. The key factors that determine the separation performance of MOFs, primarily from the perspectives of pore size, presence of open metal sites (OMS) and MOFs membranes are summarized. Besides, the challenges that must be addressed for the further development of separations utilizing MOFs are also discussed. [ABSTRACT FROM AUTHOR]

Polyurethane (PU) foams are created via the chemical reactions arising after the blending of two initially liquid components (polyols and isocyanates). They are widely used for thermal insulation, for which a small pore size is required. Some of the most efficient pore size–reducing agents have proven to be per- and polyfluorinated carbons (FCs) which are simply added in small quantities to the initially liquid mixture. However, despite their long-standing use, their modes of action have only recently begun to be studied in detail. One widely accepted explanation of their action is that they supposedly suppress diffusional gas exchange between bubbles in the liquid-foam state of the nascent PU foam (foam coarsening). However, using a new double-syringe mixing technique, we show that FCs actually act at a much earlier state of the process: they facilitate the entrainment of tiny air bubbles into PU foam systems during the initial blending process. These bubbles serve as sites for heterogeneous nucleation during the foaming process, and their large number leads to a significant reduction of the characteristic pore size. More importantly, we also demonstrate that the same overall relation is found between the air bubble density and the final pore size for systems with and without FC. Combined with a detailed analysis of the pore size distribution, we argue that the main pore size–reducing effect of FCs is to facilitate air entrainment and that foam aging–related effects only play a minor role. [ABSTRACT FROM AUTHOR]

BACKGROUND: The present study investigates the in situ electrogeneration of H2O2 by the 2e− oxygen reduction reaction in an electrochemical flow cell using three commercially available cathodic electrode materials with different interfacial properties; that is, activated carbon felt (ACF), non‐activated carbon felt (NACF) and gas diffusion electrode (GDE). RESULTS: Experiments were first performed to optimize the operating parameters and to determine the yield of H2O2 electrosynthesis. The estimated maximum yield of ~40% was achieved with the NACF electrode after 30 min of operation. Furthermore, the performance of the electrodes was investigated in two scenarios, namely (i) under conditions with O2‐saturated electrolyte and (ii) under continuous air supply, to study the differences in O2 distribution within the electrode material as a function of its interfacial properties. The maximum H2O2 concentration for the first scenario was 3.86 mg L−1 after 60 min of operation, which was obtained with the NACF electrode. In contrast, in the second scenario, H2O2 electrogeneration was significantly increased for all three electrodes, with the GDE exhibiting the best performance, at 43.3 mg L−1 after 60 min of operation. CONCLUSIONS: The properties of the electrode material play a decisive role in H2O2 electrogeneration. The hydrophilicity of the electrode is very important when O2 is dissolved in the electrolyte. Hydrophobicity is preferable when gaseous O2 is applied to the electrode as a three‐phase interface is formed, which favors the transfer/penetration of O2. The pore size of the electrode is of crucial importance, as mesoporous materials facilitate the distribution of gaseous O2 in the electrode body. © 2024 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Aluminium metal foams offer low density (∼10–15% of bulk material) possessing cellular structure that ensures unique features with high stiffens, better energy absorption, thermal and acoustic properties. Selection of different foaming agents for preparing AA6061 foam samples are indeed an industrial relevance for better control over porosity and its dimensions, strengths (tensile, flexural and compression) useful for distinguished applications. Three foaming agents such as wax powder, magnesium hydroxide, and titanium hydride are selected with varying 3–9 weight percentage to prepare metal foams viz. powder metallurgy technique. For the prepared foam samples the percentage porosity, pore dimensions (maximum pore size, and equivalent diameter) and strengths were examined. Wax powder foaming agent resulted with a maximum strength in foam samples compared to magnesium hydroxide and titanium hydride. Scanning electron microscope with energy dispersive spectroscopy analysis revealed that there is no evidence of foreign elements and confirm uniform distribution of porosity in the foam samples. [ABSTRACT FROM AUTHOR]

Microwave freeze drying (MFD) can be the rapid removal of water from vegetables and fruits. The quality of dried products can be almost identical to that of conventional freeze drying (FD). MFD can also be expected to potentially replace the conventional FD, particularly for the low cost. However, the excessive local high temperature can result in the local coking during MFD, which has failed to be effectively controlled until now. The excessive local high temperature has restricted the wide range of applications of MFD. In this study, micro-computed tomography (CT) was used to visualize the pore distribution of dried Chinese yam under different microwave loading levels and cavity pressure. A systematic analysis was implemented to determine the pore size and distribution in every partial specimen. The heat and mass transfer mechanism was given for the uneven distribution of temperature during MFD, even for the excessive local temperature. A series of numerical simulations was then carried out to verify the pore size and pore distribution of the structure model. The results indicated that the operation conditions (such as microwave loading level and cavity pressure) shared a significant effect on the pore characteristics of Chinese yam under MFD. There was a distinct distribution in the thickness of the sarcocarp, as the cavity pressure changed. The percentage of 10-50 μm sarcocarp under 200 Pa was higher than that under 100 and 300 Pa. while the percentage of 60-160 μm sarcocarp under 200 Pa was lower than that under 100 and 300 Pa. Low microwave loading level tended to form the small pores, whereas, the large pores were observed at high microwave loading level. Low cavity pressure and microwave loading levels tended to form the much smaller pores. The low microwave loading level also induced the smaller pores with a size between 50 and 160 μm. Meanwhile, the high microwave loading level tended to produce much larger pores with sizes between 200 and 550 μm. There was a significant effect of cavity pressure on the pore size and distribution in the inner specimen, whereas, there was no effect in the outer specimen. Therefore, the larger pore was more prone to form in the middle of the sample during MFD. There was a distinct effect of microwave loading level on the pore size and distribution in both the inner and outer layers. The microwave loading level was prone to produce sudden variation in the pore distribution when the pore size was larger than 800 μm. Compared with the cavity pressure, the microwave loading level can be more likely to change the pore size and pore distribution from the inside out, where a lot of large pores were formed in the inner specimen with a size of larger than 800 μm. The finding can also offer experimental support to the numerical simulation for the local high temperature in MFD. [ABSTRACT FROM AUTHOR]

In this paper, three different fracturing fluids are used as replacement working fluids, and nuclear magnetic resonance technology is used to study the oil-water replacement law of tight sandstone cores in the field, revealing the main influencing factors of oil-water replacement in the process of tight oil fracturing flow back. [ABSTRACT FROM AUTHOR]

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The highly active and selective oxygen reduction reaction (ORR) is vital to promote the performance of advanced energy conversion systems, such as fuel cells and other electrochemical devices. Porous framework materials have the capability to combine the catalytic performance of catalytic active units with their porous characteristics, making them promising oxygen reduction catalysts. However, due to the difficulty in designing and synthesizing catalytic active units, the pore size modulation of framework materials is primarily achieved by altering the linkers. We herein report the design and synthesis of three cobalt-corrole-based porous organic polymers (Co-POP-1, Co-POP-2 and Co-POP-3) with different pore sizes, which were obtained by extending 5,15-meso substituents of Co corroles. Compared to Co-POP-1 and Co-POP-2, Co-POP-3 has the largest pore size. Benefiting from the enhanced mass transfer and the highly exposed active sites, Co-POP-3 displayed remarkably boosted activity for the selective four-electron/four-proton (4e−/4 H+) ORR with a half-wave potential of E1/2 = 0.89 V versus reversible hydrogen electrode (RHE) in 0.1 M KOH solutions. This work not only presents a cobalt-corrole-based porous organic polymer catalyst with high ORR activity and selectivity but also provides a new strategy to moderate the pore size of porous framework materials.

The circular economy transition encompasses the identification of various available and sustainable materials to replace traditional binders in the construction industry. The utilization of water sediments represents this point as a beneficial action that may provide synergy in terms of waste reduction and replacement of energy-intensive materials. To explore the potential of water sediments, this study contemplated the characterization of water sediments as precursors for the design of alkali-activated materials (AAMs). The experimental approach was based on the detailed characterization of raw materials’ chemical, mineralogical, and basic material properties and the assessment of the designed AAM paste and mortar samples. The results achieved revealed the capability of low amorphous water sediments to form dense structures with favorable mechanical performance, reaching up to 36.8 MPa in compressive strength. The microstructural and water sorption characteristics point to the applicability of such materials in the building practice and, thus, the valorization of water sediments into valuable material.

The employment of 2-deoxyribose-5-phosphate aldolase (DERA) stands as a prevalent biocatalytic route for synthesizing statin side chains. The main problem with this pathway is the low stability of the enzyme. In this study, mesocellular silica foam (MCF) with different pore sizes was used as a carrier for the covalent immobilization of DERA. Different functionalizing and activating agents were tested and kinetic modeling was subsequently performed. The use of succinic anhydride as an activating agent resulted in an enzyme hyperactivation of approx. 140%, and the stability almost doubled compared to that of the free enzyme. It was also shown that the pore size of MCF has a decisive influence on the stability of the DERA enzyme. [ABSTRACT FROM AUTHOR]

The Stöber method provides a facile procedure for making carbon spheres with controlled particle sizes and is considered to be low-cost. In this study, a facile method has been established for synthesizing porous carbon spheres with variable pore sizes using a modified Stöber process. The influence of acid treatment and manipulating the carbonization process heating rate on the pore size and morphology of the particles was investigated by nitrogen adsorption, Scanning Electron Microscopy (SEM), Powder X-ray diffraction (XRD), Raman and Fourier Transform Infrared Spectroscopy (FTIR). According to the results, carbon spheres were in the size range between 1 and 7 microns. Pore size characterization shows that the pore diameter has increased by increasing the heating rate as well as by performing acid treatment. Tunable pore sizes from 2.25 to 8 nm have been evidenced by the experiments. These synthesized mesoporous carbons with different pore sizes which facilitate penetration of molecules and ions are promising as effective materials for adsorption, encapsulation and material delivery applications. [ABSTRACT FROM AUTHOR]

Concrete gets exposed to weathering. Thus, the structures sustain significant damage, significantly reducing the concrete's durability properties. Nanofillers can improve a material's ability to hydrate, which enhances the material's fresh, toughened and durability assets. The presented work is cement mortar with Ordinary Portland Cement with 10% Ultrafine slag (UFS) and various Graphene oxide (GO) mixtures (0.01% to 0.04%) subjected to 3% sulphuric acid to assess their chemical resistance. The Brunauer, Emmett and Teller analysis appraised the preliminary research by exposing the surface attributes and pore size dimensions. The test result elucidates GO 0.03% with 10% UFS was best. The evaluation of acid-exposed specimens is based on changes in the specimens' size, mass and visual scrutiny. The highest sulphate and acid resistance were observed for CMS4 and CMA4 with the least mass, length and flexure strength loss at 28 and 56 days. The surface was unaffected in microscopic studies, and there was no loss of flexural strength. [ABSTRACT FROM AUTHOR]

Vacuum membrane distillation (VMD) is an intriguing technique that has the potential to separate ethanol from an ethanol–water mixture. The goal of this work was to synthesize hydrophobic polyvinylidene fluoride–polytetrafluoroethylene (PVDF–PTFE) hybrid membranes that could be used in VMD. For membrane synthesis via phase inversion, the outcomes of different solvents, namely N-methyl-2-pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc), and dimethylformamide (DMF), as well as PTFE loading in PVDF dope solution were also evaluated. The desired membrane hydrophobicity was ensured by increasing contact angle from 69° to 135°. The obtained average maximum pore size fell between 0.19 μm and 0.22 μm. Plenty of work has been done on how the performance of the synthesized membrane depends on the VMD operating parameters (ethanol concentration, flow rate, feed temperature, and permeate pressure). The highest separation factor of 37.68 was offered by the membrane synthesized using DMF as a solvent, while the membrane synthesized with the help of DMAc solvent had the most increased ethanol flux of 10.55 kg m−2 h−1. A thorough report has been made on understanding membrane morphologies and VMD performance. [ABSTRACT FROM AUTHOR]

This study presents an integrated approach to understanding fluid dynamics in Microfluidic Paper-Based Analytical Devices (µPADs), combining empirical investigations with advanced numerical modeling. Paper-based devices are recognized for their low cost, portability, and simplicity and are increasingly applied in health, environmental monitoring, and food quality analysis. However, challenges such as lack of flow control and the need for advanced detection methods have limited their widespread adoption. To address these challenges, our study introduces a novel numerical model that incorporates factors such as pore size, fiber orientation, and porosity, thus providing a comprehensive understanding of fluid dynamics across various saturation levels of paper. Empirical results focused on observing the wetted length in saturated paper substrates. The numerical model, integrating the Highly Simplified Marker and Cell (HSMAC) method and the High Order accuracy scheme Reducing Numerical Error Terms (HORNET) scheme, successfully predicts fluid flow in scenarios challenging for empirical observation, especially at high saturation levels. The model effectively mimicked the Lucas–Washburn relation for dry paper and demonstrated the increasing time requirement for fluid movement with rising saturation levels. It also accurately predicted faster fluid flow in Whatman Grade 4 filter paper compared with Grade 41 due to its larger pore size and forecasted an increased flow rate in the machine direction fiber orientation of Whatman Grade 4. These findings have significant implications for the design and application of µPADs, emphasizing the need for precise control of fluid flow and the consideration of substrate microstructural properties. The study's combination of empirical data and advanced numerical modeling marks a considerable advancement in paper-based microfluidics, offering robust frameworks for future development and optimization of paper-based assays. [ABSTRACT FROM AUTHOR]

The drying kinetics of porous media are crucial for controlling the drying process, which is a vital component in many processes. A mathematical model of the drying process in a granular bed was developed using Whitaker's model, and its accuracy was verified through experimental results. The results indicated that the three stages of porous media drying are closely linked to the heat flow to the media and the latent heat of evaporation required by the liquid water inside it. Moreover, as the influence of gravity weakens and the capillary force strengthens, specifically due to the gradual decrease in the pore size of the bed, significant differences in the drying kinetics of the bed are observed, particularly in the third stage of drying, which is most affected. The onset of saturation in the third stage of bed drying varies with the pore size of the particles, with smaller pore sizes exhibiting an earlier onset. Additionally, the temperature change in this stage demonstrates the occurrence of secondary warming as the pore size decreases. [ABSTRACT FROM AUTHOR]