Search Results (905)

The blast furnace–basic oxygen furnace long process is the dominant steel production route in China. Increasing the scrap ratio is an effective way to reduce cost and carbon emissions, and scrap preheating is a key technology to achieve a high scrap ratio. To improve the low thermal efficiency and poor deep-bed melting performance of converter gas-based scrap preheating, an innovative process using oxygen-enriched combustion in a hot metal ladle is proposed. Numerical simulation is essential for capturing the complex multiphysics phenomena, as real-time monitoring of melting inside the packed scrap bed is extremely difficult. In this study, a novel multiphysics approach based on a User-Defined Function (UDF) is developed to dynamically track the progressive melting of the scrap skeleton, overcoming the key limitation of conventional enthalpy–porosity models that cannot capture the feedback between phase change and porous medium property evolution. A three-dimensional transient model was established, integrating turbulent combustion, gas–solid convective heat transfer in porous media, and solid–liquid phase change. The effects of impact pit depth, scrap porosity, and converter gas flow rate on temperature distribution, melting behavior, and thermal efficiency were systematically investigated. Results showed that porosity had the strongest influence; thermal efficiency increased from 33.92% to 65.59% as porosity rose from 0.6 to 0.8, due to a transition from conduction-dominated to coupled convection–conduction heat transfer. Converter gas flow rate exhibited a non-monotonic effect, peaking at 3688.14 m³·h⁻¹, highlighting a trade-off between energy input and gas residence time, while impact pit depth showed a limited effect with diminishing returns. A 600 s full-process simulation revealed stage-dependent melting, and the initial phase was crucial for process optimization. The optimal condition, with a pit depth of 64 cm, porosity of 0.8, and converter gas flow rate of 3688.14 m³·h⁻¹, achieved a 1.23% melting fraction and 65.59% thermal efficiency within 120 s. These findings clarify the combined roles of geometric confinement, permeability, and energy-residence time interactions, providing guidance for industrial scrap preheating design. Full article

We report a low-temperature plasma–liquid synthesis of crystalline β-Ga₂O₃ nanoparticles directly from aqueous solution. Pulsed discharge plasma bubbles generate reactive species that drive in situ dehydration and crystallization, bypassing the high-temperature calcination required by conventional methods. By varying the carrier gas, we tune morphology from uniform nanorice structures (He, Ar, and N₂) to amorphous microspheres (O₂ and air), revealing how plasma composition governs interfacial hydroxyl radical chemistry and growth kinetics. This approach demonstrates that localized plasma heating and reactive-species flux can achieve phase-selective oxide crystallization under ambient conditions, establishing plasma bubble reactors as a broadly applicable, low-temperature route for direct aqueous synthesis of crystalline wide-bandgap oxides that bridge solution chemistry and plasma nanomaterials design. Full article

Green synthesis of metal oxide nanoparticles is a promising route to reduce toxic reagents and energy consumption while enabling biocompatible nanomaterials for biomedical use. In this work, cerium oxide (CeO₂) nanoparticles were synthesized using lemon juice and sucrose as bio-based chelating, capping and stabilizing agents. Three synthesis routes were designed by varying the use of lemon juice, sucrose, or their combination. The synthesized materials were characterized using thermal analysis (DSC—Differential Scanning Calorimetry and TGA—Thermogravimetric Analysis), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Additionally, their antibacterial activity was assessed against Gram positive bacterium Staphylococcus aureus (S. aureus). Thermal analysis showed that heat treatment at 600 °C promotes high crystallinity, as evidenced by the development of sharp diffraction peaks associated with the cubic fluorite CeO₂ structure, and a dominant F_2g Raman mode at 463 cm⁻¹. SEM micrographs revealed nanometric particles and highlighted that combining lemon juice and sucrose effectively suppresses coalesced structures, yielding more homogeneous morphologies. Crystallite size calculations gave average sizes of 17.2 nm, with the lemon juice-only route producing the largest crystallites. Antibacterial tests revealed a clear dose-dependent inhibition of S. aureus, with marked inhibition of bacterial growth at concentrations ≥5 mg/mL and a plateau effect above 25 mg/mL. This study confirms the feasibility of using plant-based extracts as sustainable reagents for CeO₂ nanoparticle synthesis, with promising structural and biological performance for potential biomedical applications. Full article

Micro-structured SAE H13 tool steel inserts for polymer injection molding require accurate replication of sub-millimeter features while retaining adequate densification and heat-treatment response. This study compared two powder-based routes on the same hemispherical insert containing pyramidal features of approximately 0.145 mm base width: hot embossing (HE) of water-atomized SAE H13 powder (supplier d50 = 5.7 µm, irregular morphology) compounded with a commercial M1 binder, and material extrusion (MEX) of a commercial gas-atomized SAE H13 filament processed on a Markforged Metal X. Rheological screening selected a 57:43 vol% powder-to-binder ratio for the in-house HE feedstock, and DSC/TGA measurements defined two-step debinding windows. The best HE conditions were 220 °C, 8 MPa, and 45 min for the in-house mixture, and 210 °C, 8 MPa, and 30 min for the granulated commercial filament; the latter showed a 0.15% linear deviation from the silicone replica diameter among the best-rated samples. Under the tested commercial MEX configuration, the pyramidal features were not resolved because the 0.40 mm deposition line width exceeded the target feature base width, causing the slicer to omit the sub-line-width geometry. The defect populations differed qualitatively: HE specimens showed porosity and local cracking associated with powder morphology and pressureless sintering, whereas MEX specimens showed build-direction-aligned inter-raster voids associated with the toolpath. Microhardness and tensile data are therefore interpreted as process-history-specific results rather than as a direct route ranking, because sintering conditions were not uniform across all specimens. The study defines an experimentally bound process-selection limit for SAE H13 micro-tooling: HE remains preferable for sub-nozzle surface features, whereas MEX remains attractive for macro-scale geometric freedom, if resolution, densification, and post-sintering consolidation are addressed. Full article

In cold, humid environments, even a small amount of ice accumulation on the blade surface can degrade aerodynamic performance, increase drag, induce premature stall and vibration, and raise the risks of shutdown, fatigue, and ice throw. Existing blade anti-icing and de-icing strategies (such as passive coatings, electrothermal heating, hot-air systems, and hybrid designs) struggle to simultaneously meet the requirements of lightweight construction, low-voltage rapid heating, conformability to curved surfaces, erosion resistance, long-term durability, and scalable manufacturing. MXenes, particularly Ti₃C₂T_x, have attracted attention due to their high electrical conductivity, broadband optical absorption, solution processability, tunable interfacial chemistry, and good compatibility with polymer matrices. However, their oxidation issue and blade-scale deployment challenges (coating chemistry, scalable fabrication, real-world testing) remain obstacles. Based on this, this review discusses Ti₃C₂T_x-based anti-icing, de-icing, and defogging strategies for wind turbine blades, with emphasis on material properties, functional mechanisms, coating architectures, fabrication routes, durability, and scalability, and highlights their potential for lightweight and energy-efficient all-weather blade protection. Finally, future research directions for Ti₃C₂T_x-based blade anti-icing and de-icing are prospected. This review not only aims to identify key knowledge gaps in current research but also strives to provide a theoretical reference for the application of Ti₃C₂T_x in the complex service environment of real wind turbine blades, thereby moving beyond idealized laboratory conditions. Full article

In this work, Direct Numerical Simulation (DNS) investigates the combustion behaviour of a reactive transverse lean premixed jet of an ammonia blend (10% NH₃, 11% H₂, 16% O₂ and 63% N₂ by volume) injected through a rectangular nozzle in a pre-heated non-vitiated air crossflow at a pressure of 5 bar. The configuration has been chosen from a Reynolds-Averaged Navier–Stokes (RANS) test campaign to ensure low NO and low unburned fuel, while maintaining a high temperature profile at the turbine inlet. The DNS shows that the flame stabilises on the leeward side of the rectangular jet, within and downstream of the recirculation region, while high scalar dissipation and short residence times prevent persistent anchoring on the windward side. Joint statistics reveal that the reaction does not follow a constant equivalence ratio path, since intermediate progress states are shifted towards leaner mixtures by entrainment, dilution and differential diffusion. The strongest heat-release and displacement-speed events occur in localised regions where mixture state, stretch and flame-front geometry act jointly. The displacement-speed budget is mainly controlled by the chemical source term, with diffusion reducing the net propagation speed and stratification-induced cross terms remaining small. Under intense stretch, positively curved flame elements exhibit larger displacement speeds, indicating a coupled effect of curvature, preferential diffusion and local radical transport. NO formation is dominated by fuel-nitrogen chemistry: HNO and NH₂ are the main NO-producing routes, whereas N₂ and N₂O provide the dominant NO-sink channels. The DNS predicts an outlet-averaged NO level of 400 dppm, while extended-domain RANS calculations indicate that longer residence times could reduce it below 100 dppm. Full article

The coupled effects of Ni and Ti additions on amorphization, spark plasma sintering (SPS) response, and hardness evolution were investigated in Al-rich Al–Fe–Nb-based metastable alloys. Mechanically alloyed Al₈₂Fe₁₄Nb₂Ni₂, Al₈₂Fe₁₄Nb₂Ti₂, and Al₈₂Fe₁₂Nb₂Ni₂Ti₂ powders showed progressive loss of long-range order, with the quinary alloy exhibiting the strongest amorphization tendency, consistent with its higher configurational entropy (5.420 J·mol⁻¹·K⁻¹) and more negative mixing enthalpy (−9.36 kJ·mol⁻¹). SPS displacement analysis revealed that primary displacement contribution occurs during heating and is progressively limited by crystallization-induced stiffening. Consolidation at 500 °C produced amorphous–nanocrystalline composites containing Al₁₃Fe₄ and Al₃Nb, whereas increasing the temperature to 550 °C promoted further devitrification. The highest hardness, 445.4 HV, was obtained for Al₈₂Fe₁₄Nb₂Ni₂, despite its lower amorphous-forming ability than the quinary alloy. This demonstrates that hardness is controlled not by maximum amorphization, but by the kinetic balance between amorphous retention, fine intermetallic precipitation, and densification efficiency. The results identify SPS as a coupled densification–transformation route for designing high-strength Al-based amorphous–nanocrystalline alloys. Full article

Black tea quality is governed by aroma chemistry: terpene alcohols (linalool, geraniol, nerolidol), methyl salicylate, and short-chain aldehydes whose abundance and release kinetics from the polyphenol-rich leaf matrix shape perceived grade. Grade information lies not only in the average headspace concentration but in the temporal shape of volatile organic compound (VOC) release under controlled heating. Conventional electronic noses obscure this signal: they rely on multi-sensor arrays, compress each response into summary statistics, and report accuracy only at the level of individual measurements. Whether a single low-cost metal–oxide–semiconductor (MOS) gas sensor can recover grade-defining aroma chemistry, and whether waveform-level modeling can exploit it, was therefore investigated. A portable electronic nose built around a Bosch BME688 sensor recorded 90 time series, each comprising four directly measured channels (temperature, humidity, pressure, gas sensor resistance) and a derived indoor-air-quality (IAQ) proxy computed from them by the on-chip BSEC library, from 16 commercial Turkish black teas across three quality grades. Two representations were compared on the same data: a feature-based pipeline reducing 25 statistical descriptors to seven principal components for six classifiers (best F1-macro = 0.624, MLP), and a raw-waveform Multi-Scale 1D-CNN with Squeeze–Excitation and temporal self-attention (MS-CNN-Attention). Under product-grouped cross-validation, the deep model reached F1-macro = 0.811 (+30%) and graded 14 of 16 products correctly by majority vote, against 11 of 16 for the MLP, with the largest gain in the medium grade (F1: 0.52 → 0.79), where summary-statistic compression destroys the release-kinetic signal. The contributions are threefold: one programmable MOS sensor operated as a thermal-desorption profiler rather than a sensor array; a direct comparison of feature-based classical learning against raw-waveform deep learning on the same small, non-normally distributed dataset; and a product-level decision-consistency metric suited to batch screening. Pairing a low-cost MOS sensor with waveform-level modeling offers a rapid, non-destructive route to aroma-chemistry-based tea quality screening. Full article

Proactive disease transmission pathway analyses break complex transmission routes into simpler steps, making risks and uncertainties easier to identify. This approach is especially valuable for African Swine Fever (ASF), a difficult-to-control disease in low-biosecurity settings or when biosecurity practices are inconsistently applied. To support targeted biosecurity planning, a pathway analysis was conducted that is specific to pork harvest facilities in the United States. The analysis focused on two federally inspected plants that slaughter market hogs and produce primal cuts. Inputs, outputs, and potential transmission pathways were identified through a literature review, site visits, and facility personnel interviews. Because ASF virus remains stable at low temperatures and in many pork products, particular attention was given to pathways involving storage conditions, waste materials, and processing steps such as heating or pH modification. Processing steps were evaluated against existing process control plans and ASF inactivation thresholds to determine mitigation status. Of 42 identified pathways, 39 were classified as unmitigated or of unknown mitigation status. These unmitigated or unknown pathways—broadly involving pigs, people, vehicles, and waste—represent the highest priorities for further risk assessment work and for exploring ways to develop or strengthen biosecurity protocols that reduce ASF transmission. Full article

Wittichenite (Cu₃BiS₃) was synthesized by mechanical alloying (MA) followed by hot pressing (HP), and its phase evolution, thermal stability, charge transport behavior, and thermoelectric performance were systematically examined. X-ray diffraction analysis of the MA powders revealed broadened diffraction peaks, indicating reduced crystallinity and refined crystallite size. After HP consolidation, a well-defined single-phase orthorhombic wittichenite structure was obtained. These results demonstrate that the mechanically induced solid-state synthesis was effectively initiated during MA and subsequently completed through crystallization, defect relaxation, and densification during HP. The MA–HP processed specimens exhibited high relative densities of 94–98% of the theoretical value and a homogeneous microstructure without detectable compositional segregation or grain-boundary enrichment, confirming the formation of a structurally and chemically stable single-phase bulk material. Thermal analysis identified a reversible polymorphic phase transition from P2₁2₁2₁ to Pnma at low temperature, followed by structural relaxation and the onset of partial decomposition at higher temperatures, indicating that Cu₃BiS₃ retains structural integrity below 700 K, which defines the relevant operating window for thermoelectric evaluation. The samples exhibited p-type semiconducting behavior, with electrical conductivity increasing with temperature due to thermally activated hole transport and showing an additional enhancement across the structural transition region. The Seebeck coefficient remained positive over the entire temperature range and decreased gradually with increasing temperature, consistent with semiconductor transport characteristics. The thermal conductivity remained low at 0.30–0.38 W·m⁻¹·K⁻¹, with a negligible electronic contribution, confirming that heat transport is dominated by lattice phonon scattering. As a result of the combined increase in electrical conductivity and intrinsically low thermal conductivity, the dimensionless figure of merit (ZT) increased continuously with temperature and reached 0.17 at 673 K. These results demonstrate that the MA–HP route provides an effective and scalable strategy for producing phase-pure Cu₃BiS₃ with controlled microstructure and reproducible thermoelectric performance. Full article

Accelerated carbonation of cement-based materials offers a promising route for CO₂ sequestration driven by waste heat co-emitted from cement and power plants; however, existing kinetic models typically describe the low-temperature gas–liquid–solid regime near 100 °C and the high-temperature gas–solid regime near 600 °C in isolation, limiting their applicability to plant-scale reactor design. This study proposes a unified dual-regime kinetic framework spanning 20–700 °C. The low-temperature branch couples Henry’s-law CO₂ solubility, a sigmoidal water-film stability function, and an Arrhenius ionic reaction term, whereas the high-temperature branch integrates shrinking-core surface reaction and product-layer diffusion with an attenuation term near the CaCO₃ decomposition onset. Seven parameters were calibrated by bounded least squares against a 51-point temperature dataset compiled from the author’s previously published carbonation experiments. The calibrated model reproduced the bimodal temperature dependence of the carbonation degree (R² = 0.62; RMSE = 0.083), with peaks near 100 °C and 640 °C, and predicted reactor volumes of order-of-magnitude 150–200 m³ for a 1 Mt/y cement plant under three waste-heat operating points. The framework bridges particle-scale kinetic and plant-scale design, and identifies mixing as the dominant operational sensitivity at the clinker-cooler condition. Full article

Microwave-assisted polymerization is a transformative technique for synthesizing conductive polymers such as polypyrrole (PPy). Unlike conventional chemical or electrochemical methods that rely on external heating or electrode mediated oxidation, microwave irradiation induces volumetric and selective heating through dipole orientation and ionic conduction, which leads to faster reaction kinetics, improved uniformity and higher yields. This review highlights the fundamental mechanisms governing microwave polymer interactions, compares conventional and microwave-assisted polymerization routes and traces the evolution of pyrrole polymerization. Special emphasis is placed on the microwave-synthesized PPy composites and their superior electrochemical performance in energy storage, sensing and biomedical applications. Case studies of graphene/PPy, PPy–metal oxide (e.g., SnO₂@PPy nanotubes) and magnetic ferrite hybrids (e.g., BaFe₁₂O₁₉/PPy) nanocomposites demonstrate enhanced electrical conductivity, specific capacitance and more uniform nanostructures. Beyond energy storage, microwave polymerization techniques have led to the development of PPy composites that are used for sensing, antimicrobial activity and photothermal cancer therapy, highlighting the technique’s versatility across biomedical sciences. Reactor scale up, temperature and pressure control under sealed conditions, reproducibility and deeper mechanism understanding of how microwave radiation influences nucleation, chain growth, doping and charge transport were identified as the outstanding challenges that must be addressed to transform microwave-assisted synthesis from pilot to industrial scale. Overall, microwave-assisted polymerization is on its way to becoming a mainstream, energy efficient method for manufacturing high performance polymer composite materials. Full article

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

This study investigates the design and performance of lime mortars incorporating multi-phase change material (multi-PCM) systems as thermally responsive rendering materials for building-envelope applications under variable conditions. Moving beyond conventional single-PCM lime mortar approaches, this work proposes a controlled multi-PCM design framework in which a fixed total PCM dosage is distributed across selected phase-transition windows. Mortars combining PCMs with different transition temperatures (5–25 °C and 18–25 °C) were produced using two PCM types: silica-supported form-stable systems and polymeric-shell microencapsulated systems supplied as powders or aqueous slurries. All formulations contained 20% PCM and were optimized with polymeric additives, including a polycarboxylate ether-based superplasticiser and a starch-derived adhesion enhancer, to ensure suitable workability and applicability as rendering materials. Microstructural analyses showed that form-stable PCMs generated more heterogeneous pore structures, whereas polymeric-shell microencapsulated systems maintained pore structures similar to PCM-free mortars. Mortars containing metakaolin exhibited enhanced mechanical performance and durability, in some cases outperforming reference mortars, highlighting the importance of matrix refinement in the successful incorporation of multi-PCM systems. Thermal characterization revealed that form-stable systems produced broader phase transitions due to component interactions, while polymeric-shell microencapsulation preserved distinct transitions and enabled a wider, more controllable activation range. Under dynamic thermal conditions (−10 to 50 °C), all multi-PCM mortars demonstrated effective temperature buffering, achieving reductions of up to 1.5 °C during heating and 1.1 °C during cooling. Environmental and economic analyses highlighted that the benefits of PCM incorporation depend on matching PCM transition temperatures to specific climatic and application requirements. These findings position multi-PCM lime mortars as a promising route towards climate-adapted, thermally responsive renders with distributed and tailorable activation profiles. Full article

Magnesium alloys offer low density, high strength, excellent heat dissipation, and good electrical conductivity, benefiting automotive and aerospace sectors. However, magnesium and its alloys are highly susceptible to corrosion, which severely limits their practical use. In this study, the hydrothermal deposition of graphene oxide (GO) and layered double hydroxides (LDHs) was achieved on the surface of an anodized magnesium alloy, forming a GO/LDH coating. The effects of pH and various anionic corrosion inhibitors on the corrosion resistance of the GO/LDH coating were subsequently investigated. The results show that the GO/LDH coating prepared at pH 10.8 exhibits the best corrosion resistance, which is generally associated with a greater coating thickness, with its nanosheets growing in a wavy manner in all directions. This coating also shows higher crystal transparency and a denser layered structure. Based on this, anionic corrosion inhibitors including molybdate, vanadate, and tungstate were incorporated into the GO/LDH coating. Electrochemical impedance (EIS) analysis subsequently revealed that the GO/LDH–molybdate coating exhibited the highest |Z|_{0.01 HZ}, reaching ~10^5.5 Ω cm², indicating its excellent corrosion resistance. This approach offers a novel and effective route to significantly improve the corrosion resistance of magnesium alloys via synergistic coating design. Full article