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In this work, laterite (LA) and rice husk ash (RHA)-based alkali-activated materials (AAMs) with varying %RHA contents (0, 5, 10, 15, and 20%) were prepared for the removal of malachite green (MG) dye from water. The precursors and AAMs were characterized by standard methods (XRF, XRD, TG/DTA SEM, and FTIR). The SEM micrographs and iodine index values showed that the incorporation of RHA improves the microporosity of laterite-based geopolymers. The incorporation of RHA did not result in any new mineral phases after alkalinization. Geopolymerization increased both the adsorption rate and capacity of the geopolymers relative to LA by approximately 5 times. The maximum adsorption capacity was 112.7 mg/g, corresponding to the GP95−5 (5% RHA) geopolymer. The adsorption capacity was therefore not solely controlled by the RHA fraction. The adsorption kinetics data was best predicted by the pseudo-second-order (PSO) model. The adsorption mechanism entails electrostatic interactions and ion exchange. These results show the suitability of laterite-rice husk ash (LA-RHA)-based alkali-activated materials as adsorbents for the efficient sequestration of malachite green in aqueous solution. [ABSTRACT FROM AUTHOR]

The influence of a polymerisation mechanism (reversible addition–fragmentation chain transfer; RAFT vs. free radical polymerisation; FRP) on the porous structure of highly porous poly(styrene-co-divinylbenzene) polymers was investigated. The highly porous polymers were synthesised via high internal phase emulsion templating (polymerizing the continuous phase of a high internal phase emulsion), utilising either FRP or RAFT processes. Furthermore, residual vinyl groups in the polymer chains were used for the subsequent crosslinking (hypercrosslinking) applying di-tert-butyl peroxide as the source of radicals. A significant difference in the specific surface area of polymers prepared by FRP (between 20 and 35 m2/g) and samples prepared by RAFT polymerisation (between 60 and 150 m2/g) was found. Based on the results from gas adsorption and solid state NMR, it could be concluded that the RAFT polymerisation affects the homogeneous distribution of the crosslinks in the highly crosslinked styrene-co-divinylbenzene polymer network. During the initial crosslinking, RAFT polymerisation leads to the increase in mesopores with diameters between 2 and 20 nm, resulting in good accessibility of polymer chains during the hypercrosslinking reaction, which is reflected in increased microporosity. The fraction of micropores created during the hypercrosslinking of polymers prepared via RAFT is around 10% of the total pore volume, which is up to 10 times more than for polymers prepared by FRP. Specific surface area, mesopore surface area, and total pore volume after hypercrosslinking reach almost the same values, regardless of the initial crosslinking. The degree of hypercrosslinking was confirmed by determination of the remaining double bonds by solid-state NMR analysis. [ABSTRACT FROM AUTHOR]

Benefiting from the additional active sites for sodium-ion (Na+) adsorption and porous architecture for electrolyte accessibility, nitrogen-doped porous carbon has been considered the alternative anode material for Na+-storage applications. In this study, nitrogen-doped and zinc-confined microporous carbon (N,Z-MPC) powders are successfully prepared by thermally pyrolyzing the polyhedral ZIF-8 nanoparticles under an argon atmosphere. Following the electrochemical measurements, the N,Z-MPC not only delivers good reversible capacity (423 mAh/g at 0.02 A/g) and comparable rate capability (104 mAh/g at 1.0 A/g) but also achieves a remarkable cyclability (capacity retention: 96.6% after 3000 cycles at 1.0 A/g). Those can be attributed to its intrinsic characteristics: (a) 67% of the disordered structure, (b) 0.38 nm of interplanar distance, (c) a great proportion of sp2-type carbon, (d) abundant microporosity, (e) 16.1% of nitrogen doping, and (f) existence of sodiophilic Zn species, synergistically enhancing the electrochemical performances. Accordingly, the findings observed here support the N,Z-MPC to be a potential anode material enabling exceptional Na+-storage abilities. [ABSTRACT FROM AUTHOR]

The spinnability of poly (p‐phenyl‐oxadiazole) (POD) spinning dope was regulated by tuning intrinsic viscosity and temperature to make it feasible for dry‐jet wet spinning. An increase in intrinsic viscosity ([η]) and a decrease in temperature will give rise to a more significant entanglement density of the POD solution and increase viscosity. Results show that POD spinning dopes' stable extrusion can be formed at the conditions when the spinning dope's viscoelastic transition frequency (VETF) is around 10 Hz. The solution was selected to prepare POD fiber when [η] = 2.23 at 40 °C, and the tensile strength of the POD fiber was enhanced significantly (from 1.3 to 3.19 cN/dtex). The best mechanical properties were achieved when the draw ratio at the spinneret was 1.6. Our work provides an alternative for the rapid preparation of high‐performance POD fiber, which is of great significance for broadening the application field of POD fibers. [ABSTRACT FROM AUTHOR]

The importance of facile and reliable route for preparing pure beta-tricalcium phosphate (β-TCP) is immense for bone grafting application. In addition to compositional purity, repercussions related with control over development of porosity, i.e. shaping, are even greater. In this study, we considered two facile synthesis paths from aqueous solutions of calcium nitrate and diammonium hydrogenphosphate for preparation of β-TCP based powder; (I) controlled approach; a slow calcium deficient hydroxyapatite (CDHA) precipitation method with controlled pH, and (II) fast approach; a rapid CDHA precipitation, followed by calcination to obtain the β-TCP based form. After synthesis, we experimentally optimised the parameters for the production of ceramic templates with various morphology and microstructure through: (I) 3D printing, and (II) foam replication templating. Regarding the synthesis, X-ray diffraction (XRD) confirmed that the slow precipitation method yields pure β-TCP after calcination, while for the fast method, β-TCP in mixture with minor β-CPP (beta-calcium pyrophosphate) quantities was obtained. For both approaches, hydroxyapatite (HA) was not observed even in traces. The prepared porous ceramic bodies were broadly characterized through their total porosity (Archimedes' method), microporosity and specific surface (adsorption-desorption isotherms) and morphology by scanning electron microscopy (SEM). Characterisations give rise to a reliable synthetic route for preparing of highly porous monophasic β-TCP bodies. The course of shaping and porosity development of β-TCP bodies was meticulously considered. [ABSTRACT FROM AUTHOR]

Blended coal combustion technology is being adopted by more and more power plants as a clean coal combustion technology, while the combustion of coal coke accounts for more than 85% of the total combustion process of pulverized coal. In order to investigate the effects of different factors on the pore structure and fractal properties of the blended coal coke, a low-temperature nitrogen adsorption method and scanning electron microscopy are used to study the coal coke consisting of three types of coal after pyrolysis. The adsorption isotherm analysis indicates that the pore structure in blended coal coke consisted mainly of semi-open pores with semi-cates. Petroleum coke can severely inhibit microporosity when the content of petroleum coke in the blended coal sample exceeds 10%. The microporosity distribution of blended coal coke with different blending ratios is more concentrated than that of mesopores. In addition, it is found that the trend of D1 is consistent with the trend of the ratio of the microporous specific surface area to the total specific surface area in the blended coal coke. Bituminous coal will make the blended coal coke have a complex structure and petroleum coke will make it have a smooth surface. [ABSTRACT FROM AUTHOR]

Hard carbons are the most investigated materials as negative electrode for Na-ion batteries, although the exact mechanism of sodium storage remains under debate. This work is focused on the study of the sodiation mechanism of non-graphitizing carbons (NGC) prepared in a wide range of pyrolysis temperatures (1000 °C–2500 °C), thus covering the whole range from hard carbons (HC) to glassy carbons (GC). Structural and textural characterizations show that increasing the pyrolysis temperature leads to NGCs with a more ordered structure, containing fewer heteroatoms and structural defects, and particularly leads to a developed closed microporosity. In this work, in situ Raman spectroscopy at different excitation wavelengths is used to clarify the mechanism of electrochemical sodiation: it is revealed that the intercalation of Na+ between the graphene layers occurs mainly during the sloping part of the galvanostatic profile, whereas the plateau at low voltage (below 0.1 V vs. Na+/Na) can be associated with the filling of micropores with sodium. [Display omitted] • Hard and glassy carbons are synthesized at four different pyrolysis temperatures. • Materials characterizations are structural, textural and electrochemical. • Pyrolysis temperature dependence of structure, performance and Na storage mechanism. • Multi-wavelength Raman spectroscopy is used for structural and mechanistic studies. • In situ Raman spectroscopy shows intercalation-pore filling mechanism. [ABSTRACT FROM AUTHOR]

Development of new microporous organic polymers attracts significant attention due to a wide scope of promising applications. In addition, the synthesis of soluble, non-crosslinking polymers of high surface area and uniform microporosity is very challenging, and the methods for soluble microporous polymers formation are rather limited. In this work, we report a new approach to construct porous polyphenylenes which employs the Diels–Alder polycondensation of multifunctional ethynyl-containing monomers of different spatial architecture with bis(cyclopentadienone)s. The resulting polymers were soluble in common organic solvents, and their structure and properties were assessed by NMR, TGA, DSC, and SEC studies. The polymers demonstrated a specific surface area up to 751 m2·g−1 and ultramicroporous (pore size ≤ 0.6 nm) structure. N2 and CO2 adsorption–desorption data revealed that porosity parameters, e.g., specific surface area and pore sizes, can be tuned selectively by varying the type of monomers and reaction conditions. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose (BNC) has a negative surface charge in physiological environments, which allows the adsorption of calcium ions to initiate the nucleation of different calcium phosphate phases. The aim of this study was to investigate different methods of mineralization in three-dimensional microporous bacterial nanocellulose with the intention of mimicking the composition, structure, and biomechanical properties of natural bone. To generate the 3D microporous biomaterial, porogen particles were incorporated during BNC fermentation with the Komagataeibacter medellinensis strain. Calcium phosphates (CPs) were deposited onto the BNC scaffolds in five immersion cycles, alternating between calcium and phosphate salts in their insoluble forms. Scanning electron microscopy (SEM) showed that the scaffolds had different pore sizes (between 70 and 350 µm), and their porous interconnectivity was affected by the biomineralization method and time. The crystals on the BNC surface were shown to be rod-shaped, with a calcium phosphate ratio similar to that of immature bone, increasing from 1.13 to 1.6 with increasing cycle numbers. These crystals also increased in size with an increasing number of cycles, going from 25.12 to 35.9 nm. The main mineral phase observed with X-ray diffraction was octacalcium dihydrogen hexakis phosphate (V) pentahydrate (OCP). In vitro studies showed good cellular adhesion and high cell viability (up to 95%) with all the scaffolds. The osteogenic differentiation of human bone marrow mesenchymal stem cells on the scaffolds was evaluated using bone expression markers, including alkaline phosphatase, osteocalcin, and osteopontin. In conclusion, it is possible to prepare 3D BNC scaffolds with controlled microporosity that allow osteoblast adhesion, proliferation, and differentiation. [ABSTRACT FROM AUTHOR]

We developed a simplified heat-transfer model to simulate the semi-continuous casting of steel. The complicated fluid flow enhanced by natural convection and electromagnetic stirring (EMS) was abbreviated to the effective thermal conductivity in the liquid. The solidification of the cast slab was simulated using heat conduction. The system domain was designed to move according to the scenario of the casting process, with boundary conditions in fixed positions. The cast microstructure was predicted using the Hunt and Niyama criteria for columnar-to-equiaxed transition (CET) and microporosity, respectively. The simulation well predicted the experimental cast structure of the slab. The CET analysis was also compared with the simulated results using cellular automata. It was found that microporosity formed along the centerline of the slab, regardless of EMS application, and EMS did not increase or decrease microporosity in the cast slab. The simulation model developed in this study did not provide detailed results on heat transfer, fluid flow, or electromagnetic fields. However, it was successfully applied to the new semi-continuous casting process, and it proved to be a quick and effective method for analyzing the process. [ABSTRACT FROM AUTHOR]

Two numerical models based on non-equilibrium and local equilibrium approaches respectively were developed to simulate hydrogen transport in porous metals, taking account of gaseous hydrogen trapping inside the micro-porosities. They were applied to the case of hydrogen permeation in a cast steel at room temperature. Numerical simulations revealed that the two models are equivalent under certain conditions. A parametric analysis was performed to explore the effect of external hydrogen fugacity, hydrogen solubility and porosity fraction on the hydrogen diffusion behavior. A comparison between experimental permeation data and the numerical results showed reasonable agreement considering no input parameter was adjusted. [Display omitted] • Hydrogen diffusion in a metal containing micro-porosity is modelled. • Trapping of gaseous hydrogen inside the porosity is considered. • Two different approaches: non-equilibrium and local equilibrium. • Non equilibrium approach based on reaction flux at the metal – porosity interface. • Comparison to the permeation experimental data. [ABSTRACT FROM AUTHOR]

Construction and demolition waste (CDW) currently constitutes a waste stream with growing potential use as a secondary raw material in the manufacture of eco-cements that offer smaller carbon footprints and less clinker content than conventional cements. This study analyzes the physical and mechanical properties of two different cement types, ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement, and the synergy between them. These cements are manufactured with different types of CDW (fine fractions of concrete, glass and gypsum) and are intended for new technological applications in the construction sector. This paper addresses the chemical, physical, and mineralogical characterization of the starting materials, as well as the physical (water demand, setting time, soundness, water absorption by capillary action, heat of hydration, and microporosity) and mechanical behavior of the 11 cements selected, including the two reference cements (OPC and commercial CSA). From the analyses obtained, it should be noted that the addition of CDW to the cement matrix does not modify the amount of water by capillarity with respect to OPC cement, except for Labo CSA cement which increases by 15.7%, the calorimetric behavior of the mortars is different depending on the type of ternary and hybrid cement, and the mechanical resistance of the analysed mortars decreases. The results obtained show the favorable behavior of the ternary and hybrid cements made with this CDW. Despite the variations observed in the different types of cement, they all comply with the current standards applicable to commercial cements and open up a new opportunity to improve sustainability in the construction sector. [ABSTRACT FROM AUTHOR]

Chemical modifications of porous materials almost always result in loss of structural integrity, porosity, solubility, or stability. Previous attempts, so far, have not allowed any promising trend to unravel, perhaps because of the complexity of porous network frameworks. But the soluble porous polymers, the polymers of intrinsic microporosity, provide an excellent platform to develop a universal strategy for effective modification of functional groups for current demands in advanced applications. Here, we report complete transformation of PIM-1 nitriles into four previously inaccessible functional groups – ketones, alcohols, imines, and hydrazones – in a single step using volatile reagents and through a counter-intuitive non-solvent approach that enables surface area preservation. The modifications are simple, scalable, reproducible, and give record surface areas for modified PIM-1s despite at times having to pass up to two consecutive post-synthetic transformations. This unconventional dual-mode strategy offers valuable directions for chemical modification of porous materials. Chemical modification of porous materials is important for realising advanced applications, but often has a negative impact on other properties. Here, the authors report a method for the modification of polymers of intrinsic porosity to introduce a range of functional groups. [ABSTRACT FROM AUTHOR]

The relative contribution of aging hardenability to the overall dependence of tensile properties on microporosity variation in Al-6Si casting alloys was investigated in terms of the defect susceptibility concept for the quality index of tensile property. The tensile properties of as-cast and T6-treated Al-6Si-xMg alloys fabricated by the addition of 0.3-1.5 wt.% Mg were evaluated. Furthermore, the melt hydrogen concentration, melt fluidity, and scanning electron microscopy (SEM) fractographic porosity were measured. The increase in microporosity due to the decrease in melt fluidity with Mg addition was a fundamental factor in reducing the tensile strength and elongation, resulting in a lower quality index value than the nominal level in the base condition with no Mg addition. The increase in the strength coefficient and the decrease in the strain hardening exponent by Mg addition and T6 treatment were related to the increase in ultimate tensile strength (UTS) and decrease in elongation, respectively. Moreover, the defect susceptibility coefficient of the quality index based on microporosity variation decreased during T6 treatment with Mg addition. The quality index under the defect-free condition demonstrated a maximum value when 0.3 wt.% Mg was added, and its nominal value decreased gradually over a specific range of Mg addition, resulting in an increase in the fractographic porosity with a decrease in melt fluidity. The constitutive prediction of the quality index indicates the strength coefficient and strain hardening exponent determine the maximum quality index and defect susceptibility coefficient values, respectively. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks are a new class of porous organic polymers that combine excellent stability and well-defined structures. We have designed and constructed two imine COFs (COF–OH and COF–F) with micro-porosity and high stability through the Schiff base reaction. The high porosity and stability of COF–OH are due to intramolecular hydrogen bonding between hydroxyl units with nitrogen atoms in the imine linkage. The fluorine-based COF (COF–F) shows high porosity and stability due to substantial energetic stabilization in the face-to-face stacking interaction on the wall. The COFs also demonstrate high porosity as active platforms for iodine uptake up to 5.71 g g−1 and carbon dioxide uptake up to 3.92 mmol g−1via weak interactions resulting from high porosity and linkages (N atoms) to walls (N, F, and O atoms) in the aromatic skeleton. [ABSTRACT FROM AUTHOR]

Lecythis minor is a tree commonly known as Monkey pot tree. Its fruits are composed of urn-shaped epicarps, which are bulky ligneous capsules of slow degradation. Activated carbon monoliths were prepared from this fruit epicarp (bioresidue, the source of lignocellulosic matter) by chemical activation with H3PO4. The activation conditions were optimized using a central composite design, considering parameters of temperature, time, and chemical ratio as variables, and iodine and methylene blue number (IN and MBN), along with yield (Y), as responses. The best conditions for activation were 532°C (T), 1.5 h (t), and 1.5-g H3PO4/1-g raw matter (chemical ratio, CR), with response values of 996 mg I/1-g activated carbon (AC) (IN), 361-mg MB/1-g AC (MBN), and 42% (Y). Likewise, the physicochemical/surface characterization of the activated carbon Lecythis minor (ACLM) allowed establishing that it developed micro- and mesopores (Vmicro=0.72 cm3/g ; Vmeso=0.87 cm3/g), as well as ultra-microporosity, a BET surface area of 2,164 m2/g , and a total pore volume of 1.7 cm3/g ; also, the removal percentages of the emerging contaminants diclofenac and cephalexin in water were above 96%. It is concluded that fruit epicarp of L. minor is a natural-origin resource to produce AC monoliths, with satisfactory yield, desirable surface development, and high thermal stability, capable of adsorption and removal of pharmaceutical products, and other emergent contaminants from water bodies. The development of activated carbons from agricultural residues, following processes that maximize their potential as adsorbents, has great potential for the removal of pollutants in water bodies. The above takes into account that in tropical countries there are residues that are totally wasted and that can be investigated by researchers following the methods listed in this work. The pollutants that can be adsorbed vary; for example, chemical residues and medicines that are excreted from the body or that are not properly disposed, dyes, or any other residue that, due to its dimensional characteristics, is complex to capture with other techniques for cleaning water bodies (e.g., mechanical means or filters). The solution to the removal of emerging pollutants is within everyone's reach. [ABSTRACT FROM AUTHOR]

The hybrid use of a superabsorbent polymer (SAP) and expansive agent (EA) is beneficial for mitigating the autogenous shrinkage of ultra-high-performance concrete (UHPC) without compromising strength. However, the unclear mechanisms behind the synergetic effect of the two materials may hinder the more effective applications of this method. This study clarifies the interactions between SAP and CaO-based EA (CEA) in a UHPC matrix by quantifying the content and distribution of water and hydration products, underlining their influence on the strength and autogenous shrinkage evolution. The high strength of 135 MPa can be achieved in systems with a reasonable combination (S1E1, 0.1 wt%SAP, and 1 wt%CEA), and after 7 days, a 24% reduction in shrinkage was found in the same system, which is more effective than the use SAP or CEA alone at the same dose. The mitigating effect on the autogenous shrinkage of a UHPC matrix with hybrid materials at different stages depends on the competition between the water retention for self-desiccation and portlandite formation. With the continuing formation of hydration products, the microporosity of UHPC matrix under internal curing conditions at 28 d is considerably reduced, resulting in a more compact microstructure. This study also finds a suppressed crystallization pressure of growing portlandite in the extra space provided by emptied SAP, which explains the lost expansion of CEA. [ABSTRACT FROM AUTHOR]

This paper presents the results obtained from the chemical activation of bacterial nanocellulose (BCN) using fique juice as a culture medium. BNC activation (BNCA) was carried out with H3PO4 and KOH at activation temperatures between 500 °C to 800 °C. The materials obtained were characterized morphologically, physicochemically, superficially, and electrochemically, using scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), the physisorption of gases N2 and CO2 at 77 K and 273 K, respectively, cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy (EIS). The samples activated with H3PO4 presented specific surface areas (SBET) around 780 m2 g−1, while those activated with KOH values presented specific surface areas between 680 and 893 m2 g−1. The XPS analysis showed that the PXPS percentage on the surface after H3PO4 activation was 11 wt%. The energy storage capacitance values ranged between 97.5 F g−1 and 220 F g−1 by EIS in 1 M H2SO4. The samples with the best electrochemical performance were activated with KOH at 700 °C and 800 °C, mainly due to the high SBET available and the accessibility of the microporosity. The capacitance of BNCAs was mainly improved by electrostatic effects due to the SBET rather than that of pseudocapacitive ones due to the presence of phosphorus heteroatoms. [ABSTRACT FROM AUTHOR]

This study investigated the degree of grain refinement obtained with the gas bubbling flotation/filtration (GBF) treatment of A356 alloy melts upon using degassing impellers with different heat conductivities. An evaluation of the practical contribution of grain refinement and degassing treatment to the tensile properties in terms of the defect susceptibility of tensile properties to microporosity variation was made. The GBF treatment of A356 alloy melt was conducted using degassing impellers composed of pure titanium and high-purity graphite, and the grain diameter and secondary dendrite arm spacing (SDAS) in normal gravity-cast specimens and the cellular spacing in the rapid-solidified specimens were measured as the typical indices of grain refinement. The grain size, SDAS, and cellular spacing increased gradually with the degassing time, whereas the overall level of microporosity decreased independent of the impeller type used in the GBF treatment. The degree of grain refinement with the graphite impeller was higher than that with the titanium impeller, which is due to the difference in their heat conductivities, i.e., the difference in the degree of undercooling in the melt by the heat flux within the impeller. However, the grain size resulting from GBF treatment decreased to a degree greater than that obtained with no GBF treatment, and furthermore, the nominal microporosity value was not significantly affected by the impeller type, even though the degree of grain refinement gradually degraded with degassing time. [ABSTRACT FROM AUTHOR]

Porous organic molecular materials (POMMs) are a novel class of porous materials that cover a wide range of organic‐based molecular building blocks connected through weak supramolecular interactions, such as hydrogen bonds, π‐π stacking, van der Waals and electrostatic interactions. Despite of their diverse chemical and structural nature, common features to POMMs include solution processability, crystallinity and microporosity. Herein, we focus, for the first time, on the advance of the field of POMMs beyond the archetypical microporosity. In particular, we highlight relevant examples of meso‐ and macroporous POMMs, as well as hierchachical ones (micro‐/meso‐, micro‐/macro‐ and meso‐/macroporous). We also remark some of their unique properties, and how they can be key in many applications. [ABSTRACT FROM AUTHOR]

Polymers of intrinsic microporosity (PIMs) are a class of microporous organic materials that contain interconnected pores of less than 2 nm in diameter. Such materials are of great potential used in membranes for molecular separation, such as drug fractionation in pharmaceutical industry. However, the PIMs membranes are often susceptible to low separation selectivity toward different molecules due to their wide pore size distribution. Herein, a linear polyimide, Matrimid, is incorporated with PIM‐1 (a typical member of PIMs) by solution blending, and the blends are dip‐coated onto a polyimide P84 support membrane to prepare thin‐film composite (TFC) membranes to control pore size distribution while keep high microporosity. The component miscibility, pore characteristics, and molecular separation performances of the Matrimid/PIM‐1 TFC membranes are investigated in detail. The Matrimid and PIM‐1 are partially miscible due to their similar Hansen solubility parameters. The Matrimid endows the selective layers (coatings) with narrower pore size distribution due to more compact chain packing. The prepared Matrimid/PIM‐1 TFC membranes show high selectivity for separation of riboflavin (80% of retention) and isatin (only 5% of retention). The developed membranes exhibit great potential for separating molecules with different molecular weights. [ABSTRACT FROM AUTHOR]

Freeze Foams are cellular, ceramic structures with hierarchical pore structures that are manufactured using the direct foaming process. By tailoring their morphology and strength, these foam structures are able to cover a wide range of application. Earlier works identified that pore-forming influencing factors (water and air content, suspension temperature, as well as pressure reduction rate) dictate the constitution on a macroscopic and microscopic scale. Therefore, the ability to manufacture foams whose properties align with the component requirements would be an important step in advancing towards a widespread application of these promising materials. With this goal in mind, the correlation between the pore-forming influencing factors and the resulting mechanical properties was quantified. Foams with independently adjustable porosities were produced at the micro and macro scales and evaluated according to their material failure behavior under compressive loads. As a result, foams with determined macroporosities between 38 and 62%, microporosities between 25 and 42%, and compression strengths between 1 and 7 MPa with different material failure characteristics were manufactured and systematically investigated. [ABSTRACT FROM AUTHOR]

As a low energy consumption, simple operation and environmentally friendly separation method, membrane separation has attracted extensive attention. Therefore, researchers have designed and synthesized various types of separation membrane, such as metal organic framework (MOF), covalent organic framework (COF), polymer of intrinsic micro-porosity (PIM) and mixed matrix membranes. Some substituted polyacetylenes have distorted structures and formed micropores due to the existence of rigid main chains and substituted side groups, which can be applied to the field of membrane separation. This article mainly introduces the development and application of substituted polyacetylenes in gas separation and liquid separation based on membrane technology. [ABSTRACT FROM AUTHOR]

Melt electrowriting (MEW) enables the electric field‐assisted digital fabrication of precisely defined scaffold architectures of micron‐sized fibers. However, charge accumulation and consequent disruption of the precoded pattern by fiber bridging prevents controlled printing at small interfiber distances. This, together with the periodical layer stacking characteristic for additive manufacturing, typically results in scaffolds with channel‐like macroporosity, which need to be combined with other biofabrication techniques to achieve the desired microporosity for cellular infiltration. Therefore, a design strategy is devised to introduce controlled interconnected microporosity directly in MEW scaffolds by an algorithm that creates arrays of bridging‐free parallel fibers, angularly shifted from layer to layer and starting at a random point to avoid periodical fiber stacking, and hence channel‐like pores while defining micropores. This work hypothesizes that pore size can be controlled, decoupled from fiber diameter, and the mechanical properties, including anisotropy ratio, can be tuned. The authors demonstrate this while leveraging the platform for both flat and seamless tubular scaffolds and characterize them via micro‐computed tomography and tensile loading. Lastly, successful cell ingrowth into the micropores and extracellular matrix formation are shown. This platform enables microporous scaffolds entirely via MEW that can be tailored to the architectural and mechanical requirements of the target tissues. [ABSTRACT FROM AUTHOR]

Volcanic tuffs and sandstones have been used as natural building stones in the construction of monuments and buildings over the millennia of human history. Progressive weathering over time (e.g., temperature fluctuations, moisture uptake, variations in humidity, precipitation, the input of modern-day pollutants or salt crystallization) lead to damages in the internal structure of the stone. Scaling and layer-parallel flaking of rock fragments result from these types of damage-causing processes, especially when swellable clay minerals are present that lead to the generation of stresses in the rock fabric. Tuff and sandstone samples that exemplify these types of damages are investigated in this study, which were used in the construction of cultural heritage sites in Armenia, Mexico, Germany and Switzerland. Comparisons are made between these rock types considering that they show strong variations in fabric heterogeneity, grain sizes, mineralogical composition (e.g., swellable clay- and zeolite-bearing minerals), and visible macroscopic features such as depositional layering. Comprehensive investigations have been carried out that include detailed petrographic analyses, XRD analyses for the determination of the swellable and non-swellable clay fraction and minerals of the zeolite group, the cation exchange capacity (CEC), detailed SEM surveys for determining the type and localization of clays and zeolites in the rock fabric, as well as defining the petrophysical properties (e.g., porosity, capillary water uptake, water absorption, hydric expansion and mechanical properties). Moreover, this study explores the possible interaction between swellable clay minerals and zeolites (mordenite, heulandite/clinoptilolite) by conducting swelling experiments with salts and solvents and fluid-exchange experiments with and without the presence of zeolites. To explain the damages caused by the expansion in the tuffs and sandstones, two principle modes of moisture expansion are discussed when swellable clay minerals are present in the rock. These are dominantly inner or intracrystalline swelling, and secondarily, intercrystalline or osmotic swelling. When no swellable clay minerals are present, the study explains the damages in tuffs and sandstones as the result of disjoining pressure, where a high percentage of microporosity plays a pivotal role. [ABSTRACT FROM AUTHOR]

Clay mineral content and diagenetic processes are vital factors that affect reservoir quality, especially in tight clastic reservoirs, which are crucial for industrial and scientific purposes. The presence of clay minerals poses one of the most significant challenges in evaluating sandstone reservoirs' quality. Even though wireline logs may provide a good indication of the reservoir quality, there have been cases where they have failed. This work focuses on the clay minerals' impact on the porosity and permeability of a clastic reservoir. Typical outcrops from Labuan Island, Brunei–Sabah Basin, were chosen as a case study to investigate the petrophysical and petrographic parameters together with clay mineralogy profiling. The effects of the clays on the petrophysical parameters of the sandstone reservoir were evaluated through air permeability, spectral gamma ray measurements, a petrographic thin section analysis, a visual porosity estimation, and a grain size analysis. Field and petrographic studies revealed that Belait and Temburong formations contain massive, interbedded, laminated, and cross-bedded sandstones. Using an image analysis of the thin sections, porosity values ranged from 7.3% to 23.5%, with different macro and micro porosity distributions. According to the spectral gamma-ray investigation and air permeability, permeability reduction is strongly associated with clay minerals. The microporosity and permeability of the analyzed samples showed a unique pattern influenced by the grain size distribution. It was found that the textures dominated by mud grain size had a more significant impact on the air permeability and visual porosity, with coefficient of determination values of 0.83 and 0.70, respectively. The Belait Formation displayed a higher porosity and permeability compared to the Temburong Formation. This research provides new insight into the potential reservoir of Stage IV (the Belait Formation offshore equivalent) compared to Stage II (the Temburong Formation offshore equivalent). [ABSTRACT FROM AUTHOR]

In this report, nitrogen-doped porous carbons were synthesized from polyacrylonitrile fiber by a facile two-step synthesis process i.e. carbonization followed by KOH activation. Activation temperature and KOH/carbon ratio are two parameters to tune the porosity and surface chemical properties of sorbents. The as-obtained sorbents were carefully characterized. Special attention was paid concerning the change of sorbents' morphology with respect to synthesis conditions. Under the activation temperatures of this study, the sorbents can still retain their fibrous structure when the KOH/carbon mass ratio is 1. Further increasing the KOH amount will destroy the original morphology of polyacrylonitrile fiber. CO 2 adsorption performance tests show that a sorbent retaining the fibrous shape possesses the highest CO 2 uptake of 3.95 mmol/g at 25°C and 1 bar. Comprehensive investigation found that the mutual effect of narrow microporosity and doped N content govern the CO 2 adsorption capacity of these adsorbents. Furthermore, these polyacrylonitrile fiber-derived carbons present multiple outstanding CO 2 capture properties such as excellent recyclability, high CO 2 /N 2 selectivity, fast adsorption kinetics, suitable heat of adsorption, and good dynamic adsorption capacity. Hence, nitrogen-doped porous carbons with fibrous structure are promising in CO 2 capture. [Display omitted] [ABSTRACT FROM AUTHOR]

Polymers have been proven to be an interesting class of adsorbents applied in water treatment. Biopolymers are of special interest due to their unique properties such as biocompatibility, biodegradability, and reusability. This work reports a composite formed by a chitosan biopolymer and activated charcoal using sodium citrate as a crosslinking agent. The chitosan-citrate-activated charcoal composite (CCA) was characterized using FT-IR, SEM, EDAX, XRD, TGA-DTA and BET surface area analysis. The material was found to be microporous in nature with a surface area of 165.83 m²/g that led to high adsorption capacities toward both the targeted pollutants. In an aqueous phase, the dye adsorption studies were carried out with reactive orange 16 (R-16) dye, while in a gaseous phase, CO2 adsorption capacity was evaluated. Under optimum solution conditions, maximum R-16 dye removal capacity was found to be 34.62 mg g-1 CO2 adsorption capacity was found to be 13.15 cm³g-1 Intrinsic microporosity of CCA resulted in an enhanced capture capacity for R-16 dye and carbon dioxide in the respective phases. Material sustainability studies were carried out to evaluate various sustainability parameters. [ABSTRACT FROM AUTHOR]

Taking aeolian sand powder concrete as the research object, this study uses nuclear magnetic resonance, nanoindentation and scanning electron microscope to explore its micropore, mechanical and morphological characteristics and establishes the correlation between the micromechanical parameters, pore parameters and pore diameter and the relative dynamic elastic modulus of aeolian sand powder concrete. According to the gray system theory, the gray prediction model of service life of aeolian sand powder concrete based on carbonization is established. The results show that the hardness in micromechanical properties and the porosity in pore parameters have great effects on the deterioration damage process of aeolian sand powder concrete and ordinary concrete, but the effects of pores with different pore diameters are different, Harmless holes < 20 nm have a great impact on ordinary concrete, and less harmful holes between 20 nm and 50 nm have a great impact on aeolian sand powder concrete. The corrosion resistance of aeolian sand powder concrete surface is intact, while the ordinary concrete pores are damaged to varying degrees. The goodness of fit between the gray prediction model of carbonation in the service life of aeolian sand powder concrete and the measured results reaches 0.9883, which meets the requirements. [ABSTRACT FROM AUTHOR]

Casting is a fabrication method used to create various industrial parts with different shapes. Flaws such as shrinkage, porosity, and short metal filling can result in casting rejection. These flaws are heavily reliant on casting parameter design (gating and riser system design) and can be reduced by optimizing the casting parameter design. The development of materials with new or improved properties has long been the primary objective of materials scientists. The designing of metallic alloys for structural purposes must take strength, toughness, and formability into account to achieve the desired performance. The unique convergence of these essential characteristics that characterize high manganese steels fascinate scientists worldwide. The current work systematically investigated a gating system and riser design effect for high Manganese steel samples (bushes) to develop an understanding of the structure–property relationship. The first conventional manual calculation was performed to design the gating and riser system. Subsequently, a sophisticated simulation software called SolidCast was used to design, validate, and improve the casting parameters of the specimen. To back up the findings, confirmatory experiments were carried out. Both designs were used to make castings in order to check for flaws. The microstructural and mechanical characteristics of these materials were investigated. Visual inspection of the manually-designed castings revealed considerable shrinkage, whereas software-designed castings seemed in good shape, without the shrinkage, macroporosity, and microporosity. The microstructure of the specimens was also studied by applying optical microscopy and SEM analysis. By improving the gating and riser system with the SolidCast software, sound casting was achieved. This improved the quality of casting results with a considerable enhancement of yield strength (~32 percent), hardness (~34 percent), and tensile strength (~27 percent), which may lead to significant cost savings. [ABSTRACT FROM AUTHOR]

The weathering of rocks, especially the clay-rich rocks submitted to chemical attack or wet/dry cycles, may impact negatively the slopes stability. This study aims to characterize the alteration of a carbonated clay-rich material assimilated to a marl after the infiltration of polluted water as observed on Azazga site (Algeria) identified as a landslide area. The marl alteration was simulated in laboratory by wet/dry cycles and the level of material degradation was estimated using geotechnical tests (direct shear tests and fragmentation test) as well as physico-chemical measurements and microstructural observations by X-ray diffraction, mercury intrusion porosimetry, chemical analysis and scanning electron microscopy. The effect of wet/dry cycles with artificially polluted water was compared to cycles without pollutants. The tested carbonated clay-rich material composed by around 30.6% of quartz, 12.5% of carbonates and 45.1% of clays showed a higher degradation in contact with polluted water considered as an activator of the degradation. The soil porosity was evaluated with wet /dry cycles and it was estimated from 19.2 to 25% after the cycles. The degradability test (fragmentation test) agreed with the shear test results with a decrease of the cohesion c' from 49.9 to 31.5 kPa (while the friction angle remained close to 20°). Results were confirmed at micro scale with few mineralogical changes and with a higher particle aggregation in presence of pollutants resulting in rough surface while a microporosity around 30 μm appeared after cycles with or without pollutants, probably between disaggregated elongated grains or staked plans observed by SEM. In conclusions, wet/dry cycles with water (without pollutant) were mainly responsible to the disaggregation of carbonated clay-rich soil and pollutants reinforced such effect. [ABSTRACT FROM AUTHOR]

A 3D printing approach to design and produce cellular scaffolds with a precise tunable pore architecture, in terms of size, fraction, and interconnectivity is reported. Different metallic inks are formulated by mixing hydrogel with Ti–6Al–4V atomized powders of various sizes. After 3D printing by direct‐ink writing (DIW) followed by debinding and sintering, the fraction and size of macropores (D>100 μm, designed by computer‐aided design (CAD)) and micropores (D<10 μm, remaining after sintering), the roughness and the microstructure are determined by high‐resolution X‐ray tomography and electron microscopy, and correlated to the initial powder size. It is shown that playing with initial powder size allows designing different pore architectures, from interconnected micropores to fully dense filaments. These phenomena are combined with a multi‐inks DIW approach to fabricate architectured structures with graded microporosity. This new route is promising for the production of functional materials, such as biomedical scaffolds or implants, with tunable osseointegration, stiffness, and strength. The micropores could also be loaded with active molecules and positioned according to release needs. [ABSTRACT FROM AUTHOR]

Porous borocarbonitrides (denoted BCN) were prepared through pyrolysis of the polymer stemmed from dehydrocoupled ethane 1,2-diamineborane (BH3NH2CH2CH2NH2BH3, EDAB) in the presence of F-127. These materials contain interconnected pores in the nanometer range with a high specific surface area up to 511 m2 · g−1. Gas adsorption of CO2 demonstrated an interesting uptake (3.23 mmol · g−1 at 0 °C), a high CO2/N2 selectivity as well as a significant recyclability after several adsorption–desorption cycles. For comparison's sake, a synthesized non-porous BCN as well as a commercial BN sample were studied to investigate the role of porosity and carbon doping factors in CO2 capture. The present work thus tends to demonstrate that the two-step synthesis of microporous BCN adsorbent materials from EDAB using a bottom-up approach (dehydrocoupling followed by pyrolysis at 1100 °C) is relatively simple and interesting. [ABSTRACT FROM AUTHOR]

Dibenzomethanopentacene (DBMP) is shown to be a useful structural component for making Polymers of Intrinsic Microporosity (PIMs) with promise for making efficient membranes for gas separations. DBMP‐based monomers for PIMs are readily prepared using a Diels–Alder reaction between 2,3‐dimethoxyanthracene and norbornadiene as the key synthetic step. Compared to date for the archetypal PIM‐1, the incorporation of DBMP simultaneously enhances both gas permeability and the ideal selectivity for one gas over another. Hence, both ideal and mixed gas permeability data for DBMP‐rich co‐polymers and an amidoxime modified PIM are close to the current Robeson upper bounds, which define the state‐of‐the‐art for the trade‐off between permeability and selectivity, for several important gas pairs. Furthermore, long‐term studies (over ≈3 years) reveal that the reduction in gas permeabilities on ageing is less for DBMP‐containing PIMs relative to that for other high performing PIMs, which is an attractive property for the fabrication of membranes for efficient gas separations. [ABSTRACT FROM AUTHOR]

The effect of hot isostatic pressing (HIP) on the stress rupture property of K417G nickel-based superalloy is studied experimentally. The results show that the stress rupture property of the alloy is improved by the appropriate HIP process. After HIP, the average microporosity of alloy after HIP is 0.04%, which is reduced by nearly 90% compared with the as-cast microstructure. The cubic γ′ precipitates grow up, accompanied by the precipitation of the fine γ′ phase in the matrix. In addition, the area fraction of (γ + γ′) eutectic decreases, dendritic segregation is improved, and the element distribution is homogenized. As the HIP temperature increased from 1175°C to 1195°C, the microporosity and eutectic are further reduced slightly. The stress rupture life at 760°C and 645 MPa of alloys after HIP at 1175°C and 1185°C increased by 90 h and 20 h, respectively, compared with the as-cast alloy, but it is not the case for HIP at 1195°C. In addition, the elongation after HIP is increased by about 60% compared to the as-cast alloy, with an average of 4.7%. The changes in the γ′ phase and the deformation mechanism after HIP are discussed. [ABSTRACT FROM AUTHOR]

The structural and morphological properties of fullerenols upon exposure to heat treatment have yet to be understood. Herein, the temperature‐driven structural and morphological evolutions of fullerenols C60(OH) and C70(OH) were investigated. In situ spectroscopic techniques, such as variable‐temperature X‐ray diffraction and coupled thermogravimetric Fourier‐transform infrared analysis, were used to elucidate the structural transformation mechanism of fullerenols. Both fullerenols underwent four‐step structural transformation upon heating and cooling, including amorphous‐to‐crystalline transition, thermal expansion, structural compression, and new crystal formation. Compared to the initially nonporous amorphous fullerenol, the crystalline product exhibited microporosity with a surface area of 114 m2 g−1 and demonstrated CO2 sorption capability. These findings show the potential of fullerene derivatives as adsorbents. [ABSTRACT FROM AUTHOR]

Carbonate rocks are common in many parts of the world, including the Eastern Mediterranean, where they host significant groundwater supplies and are widely used as building and ornamental stones. The porosity of carbonate rocks plays a critical role in fluid storage and retrieval. The pore structure connectivity, in particular, controls many properties of geological formations, as well as the relationships between the properties of individual minerals and the bulk properties of the rock. To study the relationships between porosity, rock properties, pore structure, pore size, and their impact on reservoir characteristics, 46 carbonate rock samples were collected from four stratigraphic sections exposed near Sidon, South Lebanon. The studied carbonate rocks are related to marine deposits of different ages (e.g., Upper Cretaceous, Eocene, and Upper Miocene). In order to understand the pore connectivity, the MICP (mercury injection capillary pressure) technique was conducted on ten representative samples. Results from the SEM analysis indicate the dominance of very fine and fine pore sizes, with various categories ranging in diameter from 0.1 to10 µm. The MICP data revealed that the pore throat radii vary widely from 0.001 to 1.4 µm, and that all samples are dominated by micropore throats. The grain size analysis indicated that the studied rocks have significant amounts of silt- and clay-size grains with respect to the coarser 'sand-size' particles, suggesting a high proportion of microporosity. Obtained results, such as the poorly-sorted nature of grains, high microporosity, and the high percentage of micropore throats, justify the observed low mean hydraulic radius, the high entry pressure, and the very low permeability of the studied samples. These results suggest that the carbonate rocks near Sidon (south of Lebanon) are possibly classified as non-reservoir facies. [ABSTRACT FROM AUTHOR]

In this work, the effect of acid activation conditions on the textural, structural and adsorptive characteristics of phosphoric acid-activated carbon (AC) prepared from pentaclethra macrophylla pods (PMAC) was examined for the removal of hexavalent chromium from aqueous solution. The precursor and prepared AC were characterized by TGA, FTIR, SEM–EDX, and iodine and methylene blue indices. The TGA curves depicted the presence of hemicellulose, cellulose and lignin confirming the lignocellulosic structure of the precursor. The iodine index (908.60, 911.14 and 955.31 mg/g) and methylene blue index (49.78, 106.36 and 204.12 mg/g) increased with increasing acid:solid ratios (1:1, 2:1 and 3:1) for PMAC1, PMAC2 and PMAC3, denoting increase in microporosity and mesoporosity, respectively. The experimental data were best explained by the Elovich kinetic model and Sips isotherm with maximum adsorption capacities of 438.71, 265.911 and 406.593 mg/g for PMAC1, PMAC2 and PMAC3, respectively. The calculated mean adsorption energies were less than 8 kJ/mol, indicating that the adsorption of Cr(VI) was a physisorption process. Activation ratio of 1:1 had the fastest adsorption rate and largest adsorption capacity for Cr(VI) and is recommended as the optimal synthesis condition. [ABSTRACT FROM AUTHOR]

This paper investigates the metallurgical factors that contributed to the failure of several cast U-clamps made of HK40 steel U-clamps during the installation of a pre-startup heater in a petrochemical plant. The presence of extensive macro/micro-shrinkage porosity is identified as the root cause of the failure. The severe shrinkage-related porosity in the material, confirmed by metallographic examination and non-destructive X-ray radiography testing and evidenced by a severe loss in tensile ductility, resulted in a unique fully dendritic fracture surface characteristic. It was found that the loss of structural integrity associated with macro-shrinkage voids and loss of toughness associated with microporosity led to premature failure of U-clamps when subjected to bending forces during installation. The casting process should be designed to guarantee a higher Niyama criterion value, defined as the local thermal gradient divided by the square root of the local cooling rate, in the casting to produce a sound U-clamp. [ABSTRACT FROM AUTHOR]

Nickel-iron layered double hydroxides (NiFe LDHs) represent a promising candidate for oxygen evolution reaction (OER), however, are still confronted with insufficient activity, due to the slow kinetics of electrooxidation of Ni2+ cations for the high-valent active sites. Herein, nanopore-rich NiFe LDH (PR-NiFe LDH) nanosheets were proposed for enhancing the OER activity together with stability. In the designed catalyst, the confined nanopores create abundant unsaturated Ni sites at edges, and decrease the migration distance of protons down to the scale of their mean free path, thus promoting the formation of high-valent Ni3+/4+ active sites. The unique configuration further improves the OER stability by releasing the lattice stress and accelerating the neutralization of the local acidity during the phase transformation. Thus, the optimized PR-NiFe LDH catalysts exhibit an ultralow overpotential of 278 mV at 10 mA·cm−2 and a small Tafel slope of 75 mV·dec−1, which are competitive among the advanced LDHs based catalysts. Moreover, the RP-NiFe LDH catalyst was implemented in anion exchange membrane (AEM) water electrolyzer devices and operated steadily at a high catalytic current of 2 A over 80 h. These results demonstrated that PR-NiFe LDH could be a viable candidate for the practical electrolyzer. This concept also provides valuable insights into the design of other catalysts for OER and beyond. [ABSTRACT FROM AUTHOR]

Porous carbons can be prepared from crystalline metal–organic frameworks (MOFs) by pyrolysis. However, MOF-derived porous carbons (denoted as MPCs) are mostly composed of microporosity, potentially causing diffusional limitation during guest transport. To overcome the potential diffusional limitation of MPCs due to pore size constraints, secondary meso- or macropores need to be introduced in the MPCs. Our strategy is to granulize MOF-808 nanoparticles via spray drying, followed by pyrolysis and HF etching, yielding MPC granules with a bimodal micro-mesoporous structure, in which the micropores originate from intrinsic pores of MOF-808 and the mesopores stem from interparticle spaces between assembled MOF-808 particles. [ABSTRACT FROM AUTHOR]

Concentration gradients feature widely in many biomedical processes (e.g., cell evolution, chemotaxis, personalized healthcare, and drug screening). The concentration gradient generators (CGGs) developed previously have used either static gradients or gradients maintained by a continuous co‐flow. This article describes a platform for the manufacture of autonomous CGGs through inkjet 3D printing on a powder bed. The intrinsic microporosity of the 3D‐printed devices produces efficient flow‐independent gradient profiles. Computational fluid dynamics modeling of the porous devices reveals that mechanical dispersion, rather than diffusion or flow velocity, dominates the gradient formation. The gradients remain stable for up to 120 h with no need for external pumping systems and with minimal user intervention because on‐device evaporation and capillary forces are the sole drivers. The ease of transitioning between a computer model of an object and its fabrication allows the rapid development of custom concentration gradients. [ABSTRACT FROM AUTHOR]

The fabrication of mixed matrix membranes (MMMs) is of particular importance due to their advantages over neat membranes. The performance of MMMs is a function of the type and fraction of the nanoparticles in the membrane. Moreover, the proper interaction of the polymer and nanoparticles affects the MMMs performance. In this study polysulfone (PSf)/SBA-15 mesoporous silicas MMMs were prepared and their performance was evaluated for CO2/CH4 gas separation. SBA-15 mesoporous silicas were previously synthesized and functionalized with 3-aminopropyltriethoxysilane by post-synthesis treatment. Fourier transform infrared spectroscopy, field emission scanning electron microscopy, N2 adsorption–desorption, and Brunauer–Emmett–Teller analysis was applied to examine the functional groups, morphology, and textural properties of the unmodified and modified mesoporous silica in the prepared membrane, respectively. The effects of modified and unmodified SBA-15 particle loading were investigated for the gas separation performance of PSf/SBA-15 membranes. The experimental results illustrate that a higher modified mesoporous silica loading leads to an increase in gas permeance and gas pair selectivity. The highest increase in permeability and selectivity was related to the incorporation of S2 and AP-S2 into the PSf matrix, respectively. [ABSTRACT FROM AUTHOR]

Ultra-high-pressure hydraulic slotting technology is an effective method to realize pressure relief and permeability enhancement of a single coal seam. In this paper, through a hydraulic slotting borehole-based total gas extraction amount calculation model, it was concluded that ultra-high-pressure hydraulic slotting technology could increase the gas extraction surface area, improve the gas flow mechanism, and transform single-layer radial flow into interlayer, radial composite flow, thus greatly enhancing the gas extraction efficiency. Based on theoretical results, a field test was conducted in the Renlou coal mine, Anhui Province, China. According to the actual characteristics of the 72 coal seam in the Renlou coal mine, the key slotting parameters of this coal seam were determined. The gas extraction sources of each coal seam could be determined accurately through multi-gas source identification and tracer technology, and the effect of hydraulic slotting pressure relief and permeability enhancement was investigated. The test results indicated that the 100-day gas extraction concentration in boreholes using ultra-high-pressure hydraulic slotting technology was 2.68–7.59 times that in conventional boreholes. The average daily pure extraction volume of slotting boreholes was 3.94 times that of conventional boreholes. Based on the calculation of the gas extraction radius of boreholes in the slotted area, it was found that, under the condition of meeting the same control range of outburst elimination, drilling work could be reduced by more than two-thirds. These achievements could provide critical references for the application of ultra-high-pressure hydraulic slotting technology. [ABSTRACT FROM AUTHOR]

The mechanical properties of high-pressure die-casted parts are directly influenced by their microstructure. This article aims to evaluate the effect of the fast-shot speed on the structural component and overall microstructure for two geometrically different castings. The material used during experimental works is commonly known as the AlSi9Cu3(Fe) alloy. For experimental purposes, numerical simulations, microstructural and EDS analysis, the DAS index, length of eutectic Si plates and more were implemented. The simulations have shown the possibility of air entrapment in the filling chamber. Oxides, and consequently microporosity, were localized, which led to the selection of critical points of the casts for further observation and evaluation. With the use of the optical/scanning microscope and microhardness evaluation, the fast-shot speed value of 3.6 m.s−1 was selected as the most advantageous. [ABSTRACT FROM AUTHOR]

Zeolites and metal–organic frameworks (MOFs) are popular adsorbents when it comes to capturing CO2 from the gaseous feed stream. In this study, a hybrid of zeolite and ZIF-8 adsorbent was synthesized from coal fly ash via fusion–hydrothermal process and then in-situ aqueous ZIF-8 synthesis technique. This technique of in-situ synthesis is highly cost-effective as it is done at room temperature. The hybrid adsorbent showed an enhanced microporosity as compared to zeolites synthesized from coal fly ash due to the in-situ synthesis of ZIF-8 upon coal fly ash zeolite. It was designated as CFAZ/ZIF-8. At 298 K, a maximum CO2 uptake value of 2.83 mmol/g was observed with a constant decrease with an increase in temperature. BET surface area value of 426 m2/g was obtained for this adsorbent. Kinetics fit for the best uptake value was performed with the Avrami model kinetics, describing the adsorption well at an R2 value of 0.997 for the fit. The adsorbent also showed impressive cyclic stability after five cycles of carbonation and decarbonation. The cyclic stability studies show that the as-synthesized hybrid adsorbent shows promise in CO2 uptake studies. [ABSTRACT FROM AUTHOR]

Functionalized porous aromatic frameworks (PAFs) are excellent candidate materials for hybrid membrane fabrication. However, tailoring PAFs for membrane CO2 separation with desirable performance is still a challenge. Here, facile fabrication of functional hybrid alkylamine‐modified PAF‐1 containing membranes with high compatibility for efficient CO2/N2 separation is reported. The methylamino groups are installed on PAF‐1 resulting in PAF‐1‐CH2NH2 that has a high surface area of over 1400 m2 g–1 and unique CO2 adsorption with CO2/N2 thermodynamic selectivity of over 1000. Amidation reaction is developed for PAF‐1‐CH2NH2 cross linking with cPIM‐1 (carboxylic polymer of intrinsic microporosity), giving a homogenous compatible membrane of PAF‐1‐CH2NH2—cPIM‐1 with outstanding CO2 permeability (≈10790 Barrer) and high CO2/N2 permselectivity (≈43). This membrane outperforms the counterparts derived from parent PAF‐1 and phenylamine PAF‐1 and possesses superior performance to other relevant membranes for CO2/N2 separation. Such a membrane can selectively and stably separate CO2 from N2 in a simulated flue gas mixture, demonstrating its huge potential in carbon capture. [ABSTRACT FROM AUTHOR]

Living materials bring together material science and biology to allow the engineering and augmenting of living systems with novel functionalities. Bioprinting promises accurate control over the formation of such complex materials through programmable deposition of cells in soft materials, but current approaches had limited success in fine-tuning cell microenvironments while generating robust macroscopic morphologies. Here, we address this challenge through the use of core-shell microgel ink to decouple cell microenvironments from the structural shell for further processing. Cells are microfluidically immobilized in the viscous core that can promote the formation of both microbial populations and mammalian cellular spheroids, followed by interparticle annealing to give covalently stabilized functional scaffolds with controlled microporosity. The results show that the core-shell strategy mitigates cell leakage while affording a favorable environment for cell culture. Furthermore, we demonstrate that different microbial consortia can be printed into scaffolds for a range of applications. By compartmentalizing microbial consortia in separate microgels, the collective bioprocessing capability of the scaffold is significantly enhanced, shedding light on strategies to augment living materials with bioprocessing capabilities. Extrusion bioprinting can be used to produce living materials but controlling cell microenvironments is challenging. Here, the authors use a type of core-shell microgel ink that decouples cell culture from material processing to produce functional materials with a range of potential applications. [ABSTRACT FROM AUTHOR]

The modification of carbon‐based lithium‐ion batteries electrodes is required for the growing need of more reliable electric vehicles. Herein, a new method is introduced to fabricate vertically aligned graphene oxide (GO) films as free‐standing carbon lithium hosts for lithium‐ion batteries with enhanced performance. Vertical alignments are induced of GO in a microfluidic channel by controlling flow rates and patterns of GO suspensions. The vertical alignments are preserved and spontaneously form porous microstructures by Pulse Freezing the GO solutions inside the channel. This combined process results in the increase of levels of microstructure porosity and vertical alignment of GO films. The alignment and porous microstructures increase both electron and ion transfer capabilities across the prepared film. The half‐cell performance of aligned GO films shows a specific capacity of 440 mAh g−1 at a current density of 0.5 A g−1 after 150 cycles. This is a 190% specific capacity increase compared to the performance of a half‐cell prepared with GO without the high level of vertical alignment and microporosity. The significant increase in the value and stability of specific capacity and higher rates of charge transfer favor the promising application of carbon‐based lithium‐ion batteries for electric transportation industries. [ABSTRACT FROM AUTHOR]