Search Results (605)

There is increasing interest in structured layered double hydroxide (LDH)-based catalysts because they combine tunable acid–base/redox chemistry with reactor architectures that can reduce diffusion lengths, improve heat management, and lower pressure-drop penalties. This review evaluates LDH, LDH-derived oxide (LDO/MMO), reduced metal/LDO, reconstructed hydroxide-rich, and mixed dynamic states integrated into honeycomb monoliths, open-cell foams, meshes/felts, thin films, washcoats, coated plates, microchannels, capillaries, and additively manufactured lattices. To move beyond descriptive comparison, the literature is assessed using unified evaluation dimensions: operative active state, support architecture, coating/integration route, active-phase loading, coating thickness and uniformity, reactor-volume-normalized productivity or STY, ΔP/L, axial/radial thermal gradients, time-on-stream, coating loss, regeneration recovery, and pilot-readiness. Representative benchmarks illustrate both the promise and reporting gaps of the field: NiFe-LDH-derived monoliths for CO₂ methanation have reached ~70% CO₂ conversion at 300 °C with >90% CH₄ selectivity and only 0.7% post-test mass loss; NiFe-LDH/iron-foam monoliths retained 85% ozone conversion after 168 h; high-entropy LDH-derived oxides showed T50/T90 values of 246/254 °C for toluene oxidation; and Au/LDH capillary films achieved 31.9% glycerol carbonate yield and 3.78 g h⁻¹ g⁻¹ productivity. The strongest current cases are pollution abatement and CO₂ methanation, whereas biomass upgrading, fine-chemical flow, high-entropy coatings, and photo/electrocatalytic films require deeper module-level validation. Overall, structured LDH catalysts should be treated as coupled chemistry–coating–reactor systems whose performance must be judged simultaneously by activity, accessible catalyst inventory, transport efficiency, pressure drop, thermal profile, durability, regeneration, and manufacturability. Full article

The development of multifunctional biomaterials for bone repair requires precursors that combine bioactivity, moderate antimicrobial growth-inhibitory effect, and imaging. This study demonstrates the multifunctional versatility of a single family of rare-earth-doped β-tricalcium phosphates (β-TCPs), Ca₉Eu(PO₄)₇ and Ca₉Dy(PO₄)₇, across three distinct formats: bioactive thin films (for implant coatings), brushite cements (for injectable bone fillers), and radiopaque PMMA bone composites (for load-bearing applications). This work serves as a proof-of-concept that the same doped phosphate precursors can address different clinical needs while retaining bioactivity, antimicrobial properties, and radiopacity. The phosphate precursors were synthesized via solid-state reaction. Pulsed laser deposition (PLD) was used to form amorphous, dense, and crack-free coatings, which exhibited excellent in vitro bioactivity through the rapid dissolution–reprecipitation of a carbonated apatite layer in simulated body fluid. The brushite-based bone cements were produced from doped β-TCPs. These cements demonstrated high cytocompatibility with mesenchymal stromal cells (>89% viability) and significantly enhanced osteogenic differentiation with antimicrobial activity against common pathogens (S. aureus, E. coli, P. aeruginosa). Furthermore, incorporation of these phosphates as fillers into PMMA bone cement resulted in a homogeneous particle distribution with reduced agglomeration compared to undoped β-TCPs, achieving clinically relevant radiopacity values (913 ± 22.4 HU for Dy-doped sample). Post-mortem studies by the CT method were performed on the vertebrae with PMMA–phosphate composites and brushite cements. It was shown that brushite cement in ovine lumbar vertebrae defects exhibited the highest radiopacity (1450–1550 ± 25 HU). The findings establish rare-earth-doped β-TCP as a unified multifunctional precursor that imparts bioactivity, the ability to support in vitro mineralization, antimicrobial properties, and enhanced radiopacity to thin films, phosphate cements, and polymer composite materials. Full article

A capacitor electrode has been developed, obtained by electrophoretically filling the nanosized pores of anodic alumina with carbon particles and PVDF. By pre-thinning the barrier anode layer, direct contact of carbon with the aluminum current collector has been achieved. The multilayer electrode from {carbon particles and PVDF}/{carbon black and porous AAO}/{aluminum current collector} was studied using Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and atomic force microscopy. The analyses demonstrate the highly developed surface of the electrodes and the good binding ability of the PVDF. The electrochemical properties of the electrodes were investigated in a 0.5 M Na₂SO₄ aqueous electrolyte using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge. The electrode allows operation at a high voltage window of 5.75 V. The electrochemical results show that the electrodes have a specific capacitance of 4.25 ± 0.35 F g⁻¹, a specific energy density of 19.3 Wh kg⁻¹ and specific power of about 5600 W kg⁻¹ with stable operation over 10,000 cycles. Therefore, the strategy of using electrophoretic deposition of carbon materials seems promising for obtaining inexpensive capacitive layers with good adhesion to aluminum, operating stably in a wide voltage window. Full article

This study systematically investigates the intrinsic vertical breakdown characteristics of 8-inch GaN-on-Si high-electron-mobility transistor (HEMT) buffer layers (extending up to the GaN channel layer) using a vertical electrode configuration. By comparing samples with different carbon doping doses, AlN insertion layers, and superlattice cycle numbers (buffer layer thickness), combined with Technology Computer-Aided Design (TCAD) simulations, the relevant mechanisms are revealed. The results show that buffer layer thickness is a critical factor determining the vertical breakdown voltage. Its increase effectively reduces the longitudinal average electric field, widens the depletion region, and increases the breakdown voltage by approximately 50%. Carbon doping compensates for carriers and suppresses leakage through deep-level acceptor traps. Inserting thin AlN layers into the superlattice has a limited effect on improving breakdown voltage. This research provides clear experimental guidance for the optimal design of high-voltage GaN HEMT buffer layers from both material and physical perspectives. Full article

Studying carbonate breccias enhances our understanding of various geological processes. Fieldwork in the vicinity of the Sakhray Massif in the Western Caucasus (western edge of the Caucasus Mountains) allowed us to discover a peculiar layer of carbonate breccia in the monotonous succession of Lower Triassic platy limestones. The lithological peculiarities of this breccia and the hosting rocks were examined in the field, as well as in polished slabs and thin sections. The results show that the breccia consists of a chaotic mass of chiefly angular clasts of entirely different limestones with abundant fossil debris and a micritic matrix similar to the hosting rocks but bearing siliciclastic debris. The age of the carbonate breccia is the same as that of the hosting rocks, i.e., it is late Induan–early Olenekian (Early Triassic), but the clasts are attributed to upper Changhsingian (Upper Permian) limestones (also reefal). It is proposed that these clasts were created by erosion in a subaerial environment, after which they were transported from a land mass to a deep sea. Apparently, extraordinary geological events (e.g., severe storms, earthquakes, or tsunamis) triggered submarine debris flows on a steep slope. From a practical point of view, the reported discovery extends the vision of the geological heritage of this part of the Western Caucasus. Full article

Sulfur-containing medium-carbon microalloyed steel blooms are widely used for high-load automotive components, and reducing surface defects is important for improving product yield and lowering downstream processing costs. To address surface defects such as star cracks and microcracks in the continuous casting of these steel blooms, this study redesigned the mold flux on the basis of the steel’s solidification characteristics and crack susceptibility and carried out a twin-strand industrial comparative casting trial. Thermodynamic and thermophysical analyses indicated that the relatively high contents of S, Mn, and Ti/N in the steel promoted the precipitation of MnS and TiN–MnS complex inclusions along grain boundaries, severely weakening grain boundary cohesion. Meanwhile, the high specific heat capacity and low thermal conductivity further intensified thermal stress concentration in the solidifying shell, rendering the steel highly susceptible to cracking. Evaluation of the originally used mold flux (Flux A) revealed that its high melting temperature (1189 °C), long melting time (106 s), high break temperature (1170 °C), and poor crystallization behavior resulted in an excessively thin liquid slag layer (<5 mm) within the mold, making it difficult to provide adequate lubrication and stable heat transfer; these were key external factors inducing surface defects. Accordingly, the optimized mold flux (Flux B) was designed and prepared by increasing the basicity from 0.95 to 1.1, raising the Al₂O₃ content from 9.48% to 11.16%, increasing the F content from 4.93% to 5.58%, and reducing the carbon content from 13.85% to 6.97%. The rheological and crystallization properties of the flux were optimized in a coordinated manner, allowing uniform heat transfer through the crystalline slag layer while maintaining adequate lubrication. Industrial comparative trials demonstrated that Flux B stabilized the liquid slag layer at 8–10 mm, increased slag consumption to 0.56 kg/t, and significantly reduced surface defects such as star cracks and microcracks on blooms. The ultrasonic testing acceptance rate for rolled products increased to 98.6%, thereby meeting stringent quality requirements for the continuous casting of sulfur-containing, medium-carbon, microalloyed steel blooms. Full article

Salt cavern Compressed Air Energy Storage (CAES) is one of the critical technologies for energy storage and an important infrastructure supporting the construction of new power systems and facilitating the achievement of the dual carbon goals. The salt rock resources in China are primarily composed of continental strata salt rocks, characterized by high heterogeneity, well-developed thin-layer interbedding, dissolution resistance among different lithologies, and significant creep variations. These features, to some extent, limit the improvement of wellbore construction accuracy, the reliability of abandoned well sealing, the safety of natural gas storage operations, and enhancements in gas injection–brine displacement efficiency. This study takes the continental bedded salt rock in the Dawenkou Basin as the research object and adopts a method combining theoretical analysis and field engineering verification to improve the systematic construction technology system, covering the whole process of drilling engineering, abandoned well plugging, the design of an injection and brine extraction device, and gas injection and brine drainage. The research results optimize four key technologies, including precise wellbore trajectory control, dual-section milling, and multi-stage redundant plugging of abandoned wells and long-term anti-corrosion completion with laser cladding, and dual-mode adaptive gas injection and brine drainage, and improve the technical system from wellbore construction to salt cavity formation. This study can provide valuable theoretical references and engineering demonstration guidance for underground space development projects in similar salt basins in China. Full article

This study systematically investigated flow boiling characteristics within a novel three-layer microchannel heat sink with 3/4 open-ring pin fin arrays, designed for high-heat-flux thermal management of low-carbon metallurgical reactors. Two-phase flow regimes, pressure drop, and wall temperature responses were analyzed. To evaluate the impact of functional surface material properties on thermo-hydraulic behavior, a hydrophilic nano-coating modification was applied to the inner copper channel walls for comparison. Increasing the flow rate triggered a transition from a vapor-dominated confined slug flow to a liquid-dominated dispersed bubble flow, which effectively improved the thermo-hydraulic stability. Hydrophilic surface modification resulted in an average pressure drop reduction of 33% and significantly diminished the sensitivity of flow resistance to velocity variations. Through hydrophilic treatment, the localized vapor film effect at high velocities was suppressed, and temperature field homogenization was promoted, yielding a maximum convective heat transfer coefficient of 7760 W/(m²·°C), i.e., 72.9% enhancement over the baseline heat sink. The underlying mechanism is attributed to the formation of a stable near-wall thin liquid film and the promotion of high-frequency nucleate boiling. These results will be of high relevance for developing efficient cooling solutions for power electronics, thereby supporting the advancement of low-carbon metallurgical reactors. Full article

Background/Objectives: The aim of this study was to investigate the effects of intraocular pressure (IOP)-lowering drops on the sublayers of the human tear film as assessed by a novel nanometer-resolution Tear Film Imager (TFI, AdOM, Israel). Methods: In a prospective, cross-sectional study, 98 eyes from 56 adult human subjects were imaged using the TFI. The dataset included data from 18 eyes from 12 subjects treated with preserved IOP-lowering drops and 80 eyes from 44 control subjects not under ocular hypotensive therapy. Subjects in the IOP treatment group used a variety of IOP-lowering medications, including prostaglandin analogs, beta-blockers, carbonic anhydrase inhibitors, alpha agonists, and combination drops. A linear mixed effects model was used to assess the association between IOP-lowering therapy and tear film (TF) metrics, controlling for age and intra-individual correlation. The following parameters were measured: muco-aqueous layer thickness (MALT), muco-aqueous layer thinning rate (MALTR), lipid layer thickness (LLT), lipid map uniformity (LMU), inter-blink intervals (IBI), and lipid break-up time (LBUT). Results: Average ages significantly differed (p = 0.013) between the treatment group (66.5 years) and control group (average age 51.5 years), and thus results were adjusted for age accordingly. IOP was 17.1 mmHg in the treatment group and 16.1 mmHg in the control group. When analyzing the sublayers of the TF, MALTR had a significant association with IOP-lowering therapy after adjusting for age, with a difference of −52.68 nm/s; 95% confidence interval [−96.87, −8.48]; p-value = 0.020. Additionally, IBI was significantly associated with IOP-lowering therapy after log transformation (p = 0.049), with shorter IBI in the treatment group. All other metrics (MALT, LLT, LMU, and LBUT) were statistically insignificant (p > 0.05). Conclusions: These pilot results suggest that IOP-lowering drops may accelerate thinning of the TF, specifically the muco-aqueous layer. Longitudinal studies with significantly larger samples are needed to specify the differential impact of various ocular hypotensive therapies on the human TF and the clinical implications of these findings. Full article

Voice disorders severely limit verbal communication, creating a need for intuitive assistive technologies. To meet this need, we present epidermal strain sensors that capture strain signals during silent speech and hand gesture. A thin electrospun nanofiber layer integrated onto commercial polyurethane films guides uniform, controlled microcrack formation in screen-printed carbon conductive paths, achieving a gauge factor up to 243 over 0–40% strain. Signals from the seven-channel strain sensor array are recognized by a hybrid neural network that combines convolutional and Transformer architectures, reaching over 98% accuracy. The recognized outputs are rendered in virtual reality (VR), enabling intuitive, real-time communication. Moreover, the approach simplifies fabrication by enabling crack-based strain sensing with only a thin electrospun surface layer on commercial polyurethane films, eliminating the need for thick freestanding electrospun substrates. This cost-effective approach addresses limitations of conventional electrospun substrates by minimizing the thickness of the electrospun layer, thereby shortening the electrospinning time. Overall, the work demonstrates a method for translating natural non-verbal expressions into speech and text in VR, with promising applications in healthcare and assistive communication. Full article

Floating rafts are thin, flat mineral layers that precipitate at still air–water interfaces. They are composed of calcite, aragonite, vaterite, gypsum, trona, carnallite, and/or halite. Floating rafts present a flat surface at the top in contact with air, and a rough surface at the bottom, which develops as they grow into the water. In this work, we describe floating rafts from hypersaline environments using imaging and analytical microscopy techniques. The four rafts studied consist of interconnected polycrystalline grains. Scanning electron microscopy (SEM) showed that the top surfaces were flat, whereas in the bottom surfaces, the grains protrude into the water. High magnification revealed nanoparticles arranged in stacks, suggesting growth through the organized agglutination of nanocrystals. Electron diffraction of two of the rafts indicates that they consist of aragonite. Accordingly, electron energy-loss spectroscopy (EELS) shows the C K-edges characteristic of carbonates, along with O and Ca edges. Energy-dispersive spectroscopy (EDS) in the SEM also revealed a few Ca sulfate crystals on the bottom surface. In addition, the presence of cubic shapes indicates the presence of halite. We hypothesize that the genesis of these rafts is driven by evaporation of still water, which increases supersaturation at the very surface, leading to mineral nucleation at the air–water interface, where the activation energy is lower. Full article

The energy utilization of residual woody biomass is a relevant strategy for the decentralized energy transition and local waste management in rural areas. The objective of this study was to characterize (physically, chemically, and energetically) five types of residual biomass: pine branches, huinumo (this material refers to the long, thin pine needles that, after drying and falling, form a layer on the forest floor), cherry branches and leaves, and grass waste generated in the community of San Francisco Pichátaro, Michoacán, Mexico, in order to evaluate its viability for the production of densified solid biofuels. A comprehensive analysis was conducted, including moisture content, higher heating value, proximate characterization, structural chemical analysis (using the Van Soest method), elemental CHONS analysis, ash microanalysis (by ICP-OES), and a multicriteria analysis with normalized energy and compositional indicators. The results showed that huinumo and cherry leaves were the most outstanding biomasses, presenting the highest heating values (20.7 MJ/kg) and low moisture and ash contents. Pine branches obtained the most balanced results, characterized by their equilibrium in fixed carbon and lignin, as well as their low potassium content. The multicriteria analysis showed that there is no absolute optimal biomass; however, it indicates that pine branches and huinumo are the most robust feedstocks for the production of briquettes or pellets. The results confirm the significant technical and environmental potential of local lignocellulosic residues for the production of solid biofuels and for contributing to sustainable energy solutions at the local scale. Full article

The rising demand for clean water has reinforced the importance of thin-film composite TFC polyamide membranes in desalination and wastewater treatment. While improvements often target the selective layer, these can sometimes reduce stability or selectivity. An alternative approach is to tailor the porous support, particularly through the incorporation of nanomaterials such as metal oxides, carbon-based nanomaterials, metal–organic frameworks (MOFs), zeolites, and cellulose-based materials, to improve overall membrane performance. The modification of membrane substrates through the incorporation of nanofillers has demonstrated notable advantages, including enhanced hydrophilicity, improved mechanical stability, and increased porosity. These improvements collectively contribute to higher permeability, reduced internal concentration polarization and enhanced separation performance in FO, NF, and RO applications. The review starts by clearly distinguishing substrate modification, in which nanomaterials are localized in the porous support, from interlayer modification, which involves constructing a distinct layer between the support and selective layer. This concise review highlights current developments in the nanomaterial-based support modification of polyamide TFC membranes; it summarizes nanomaterials selections, incorporation techniques, and resulting property changes. Current challenges and potential research opportunities are also discussed. Full article

This study presents an experimental investigation into a novel hybrid strengthening system for reinforced concrete (RC) beams that combines externally bonded carbon-fiber-reinforced polymer (CFRP) sheets with a spray-applied polyurea coating (Linex XS-350). Seven beams were tested under four-point bending to evaluate the effects of two main parameters, CFRP thickness and single vs. double layers, and polymer coating configurations, i.e., none, thin with 2 mm, thick with 4 mm, and embedded. The coating was intended to act as an elastic confinement layer that mitigates peeling stresses and enhances CFRP concrete bond performance. The results demonstrated significant improvements in strength, ductility, and strain capacity for coated specimens compared with CFRP-only beams. The inclusion of Linex increased the ultimate load by up to 24% in single-layer beams and 20% in double-layer beams, while bottom-fiber strain at failure increased by more than fivefold, indicating enhanced CFRP utilization. The uncoated beams failed prematurely by CFRP peeling, whereas the coated and embedded specimens transitioned to CFRP rupture with more gradual and ductile behavior. The combined use of multiple CFRP layers and polymer coating produced the most effective performance, with the double-layer embedded configuration (B7) achieving the highest load, strain, and energy absorption. The findings confirm that integrating polyurea coatings with CFRP can effectively delay debonding and significantly improve the reliability and toughness of strengthened RC members, offering a practical solution for more resilient structural retrofitting. Full article

With the expansion of global oil and gas resource exploration and development into deep and ultra deep layers, the efficient development of deep carbonate rock fracture cave reservoirs has become the key to ensuring energy security. However, this type of reservoir commonly faces high temperatures, high salinity, and extremely strong heterogeneity, leading to increasingly severe water content spikes caused by dominant water flow channels. Although the existing traditional inorganic plugging agent has good temperature resistance, it has the defects of great brittleness and easy cracking, while the organic polymer gel is prone to degradation failure under high temperature and high salt environments. In order to solve the above problems, a new biochar-enhanced inorganic composite gel system was constructed by using biochar prepared from agricultural and forestry waste pyrolysis as a functional enhancement component. Through rheological testing, high-temperature and high-pressure mechanical experiments, long-term thermal stability evaluation, and dynamic sealing experiments of fractured rock cores, the reinforcement and toughening laws and rheological control mechanisms of biochar on inorganic matrices were systematically studied. Research has found that a biochar content of 0.5 wt% can significantly improve the micro pore structure of the matrix. By utilizing its micro aggregate filling effect and interfacial chemical bonding, the compressive strength of the solidified body can be increased to over 2 MPa, and there is no significant decline in strength after aging at 130 °C for 30 days. More importantly, the unique “adsorption slow-release” mechanism of biochar effectively stabilizes the hydration reaction kinetics at high temperatures, extending the solidification time of the system to 15 h and solving the problem of flash condensation in deep well pumping. This system exhibits excellent shear thinning characteristics and crack sealing ability, and presents a unique “yield reconstruction” toughness sealing feature. This study elucidates the multidimensional strengthening mechanism of biochar in inorganic cementitious materials, providing technical reference for stable oil and water control in deep fractured reservoirs. Full article