Search Results (196)

Efficient separation of cocoa shell and kernel is a critical operation in semi-finished cocoa processing, where conventional mechanical methods such as grinding, cutting, and rubbing often generate excessive heat, leading to cocoa butter melting and degradation of kernel quality due to its high fat content. To overcome these limitations, this study pro-poses a dynamic impact-based framework for a small-scale centrifugal cracking system, in which fracture is induced by controlled kinetic impact rather than compressive loading. A combined theoretical and experimental investigation was conducted on roasted cocoa beans at a small industrial scale. Mechanical characterization showed that the mean and maximum shell fracture forces were 23.515 N and 54.382 N, respectively, while kernel fracture forces were significantly higher at 91.896 N and 195.327 N. A dynamic analysis of the centrifugal cracker identified a critical rotational speed range of 812–975 rpm, corresponding to impact velocities of 17.14–20.57 m/s and kinetic energies of 0.17–0.25 J per bean. Experimental validation indicated an optimal operating range of 860–900 rpm, achieving less than 1.1% uncracked beans and less than 2% fine nibs (<3 mm). Below 800 rpm, incomplete cracking was observed, whereas speeds above 950 rpm increased kernel fragmentation. These results demonstrate that precise control of impact energy is the key factor governing efficient centrifugal cracking performance in cocoa processing. Full article

Starch-based bioplastics are renewable and biodegradable, but their wider use is constrained by moisture sorption, humidity-dependent aging, insufficient tensile performance, and weak water- and oxygen barrier stability. This review critically synthesizes the peer-reviewed literature from 2020 to 2026 on enzymatically engineered starch for film, packaging, and thermoplastic applications using an architecture–property framework that links enzyme specificity, chain-length distribution, crystallinity, processing route, and material response. Controlled α-1,4 hydrolysis mainly improves processability by lowering molecular weight, viscosity, and gelatinization resistance. However, excessive hydrolysis can increase water uptake, solubility, and loss of cohesive strength. Debranching by pullulanase or isoamylase increases amylose-like linear chains and can promote B-type crystallinity or V-type starch–lipid complexes, with reported gains in tensile strength, contact angle, and water vapor barrier when the chain lengths and recrystallization conditions are controlled. Branching enzymes and transglycosylases increase branch density or redistribute glucan chains, suppressing retrogradation and improving flexibility, water retention, and aging resistance, but often with trade-offs in strength, crystallinity, and barrier performance. Lipase- and laccase-catalyzed functionalization expands starch functionality by increasing hydrophobicity, compatibility with hydrophobic phases, antioxidant activity, and active-packaging potential. The evidence indicates that enzymatic modification should not be generalized as uniformly improving starch bioplastics; performance gains are conditional on the starch source, amylose content, enzyme dosage, reaction severity, plasticizer composition, processing method, film conditioning, and storage humidity. Industrial implementation remains limited by enzyme cost and reuse, high-solids mass transfer, reaction time, enzyme stability under heat and shear, and reproducibility across botanical sources. Overall, enzymatic molecular editing is most promising when mechanistic architecture control is coupled with standardized structure–property reporting and scalable processing, such as immobilized-enzyme reactors, high-solids systems, and reactive extrusion. Full article

Ultra-high-performance concrete (UHPC) typically contains high cement and steel-fiber contents, leading to high cost and carbon emissions. This study developed a low-carbon UHPC by partially replacing cement with industrial solid waste (ISW) composed of ground granulated blast-furnace slag and calcium carbide slag, and by partially replacing steel fibers with recycled plastic fibers (RPF). The effects of ISW and RPF on flowability, mechanical properties, hydration behavior, microstructure, carbon emissions, and raw-material cost were investigated. ISW had a limited influence on flowability, whereas RPF markedly reduced flowability. Appropriate ISW and RPF contents increased flexural and compressive strengths by up to 41.02% and 14.93%, respectively. The 30% ISW-50% RPF mixture provided the highest flexural strength, while 30% ISW-30% RPF achieved the highest compressive strength with acceptable flowability. Hydration heat, XRD, SEM, and FTIR analyses showed that moderate ISW promoted early hydration and C-S-H/C-A-S-H gel formation, whereas excessive ISW caused dilution and reduced matrix compactness. Therefore, 30% ISW-30% RPF is recommended as the balanced formulation, whereas 50% ISW-50% RPF is more suitable for carbon- and cost-sensitive applications and maintains approximately 150 MPa compressive strength. Full article

The dual reliance on surface-mount technology (SMT) and pin-through-hole (PTH) assembly lines in high-volume printed circuit board (PCB) manufacturing induces logistical bottlenecks, excessive operational costs, and elevated thermal stress on components. This study presents the optimization of a wireless detector terminal production line by integrating Pin-in-Paste (PiP) technology within a Six Sigma DMAIC (Define, Measure, Analyze, Improve, Control) framework. By accurately calculating the required solder volume ($V_{req}$) and stencil aperture dimensions based on pin and pad geometries, the wave soldering process was eliminated without altering existing thermal profiles. The integration consolidated the assembly into a single heat cycle, ensuring IPC-A-610 Class 2 compliance for barrel fill ratios. The results demonstrate a 97% reduction in average assembly costs, yielding annual savings of USD 92,513 while eliminating USD 44,025 in work-in-progress (WIP) inventory. Furthermore, the single-reflow approach mitigated component thermal degradation and reduced the facility’s carbon footprint by an estimated 13.32–17.76 metric tons of CO₂ equivalent annually. This research validates a comprehensive methodology for transitioning to PiP technology, offering a sustainable, cost-effective framework for operational excellence in the electronics’ manufacturing industry. Full article

This study presents the results of long-term field experiments investigating the effects of subsurface heating and irrigation with discharged warm water (28–35 °C) on the hydrothermal, redox, biological, and salt regimes of Haplic Chernozem (Loamic, Endocalcaric) in the central Forest-Steppe zone of Ukraine. The experiments were conducted under contrasting hydro-meteorological conditions, allowing assessment of thermo-reclamation practices across a wide range of temperature and soil moisture regimes. Subsurface heating increased soil temperature by 7.3–11.1 °C at the depth of heating pipe installation, while the thermal effect gradually decreased with increasing distance from the heat source. Combined heating and irrigation created a more uniform temperature distribution within the root zone, reduced the depth and duration of soil freezing, and improved hydrothermal conditions throughout the growing season. The studied soils maintained predominantly oxidative conditions under all treatments. However, the combined application of heating and irrigation promoted a more homogeneous distribution and seasonal stabilization of soil redox potential throughout the profile. Soil heating also enhanced microbiological activity, thereby increasing cellulolytic activity, particularly during cold and dry periods when soil temperature and moisture limited microbial processes. Irrigation with slightly mineralized warm wastewater did not cause significant overall soil salinization but resulted in the redistribution of calcium and sodium within the soil profile. Subsurface heating intensified the seasonal dynamics of readily soluble salts, promoting their temporary accumulation near the heating pipes, whereas combined heating and irrigation facilitated subsequent leaching of excess salts into deeper horizons. The integrated application of subsurface heating and irrigation produced the highest and most stable perennial grass productivity, increasing biomass yield by 87–163% compared with the control, irrespective of meteorological conditions. These findings demonstrate that the integrated use of industrial waste heat for subsurface heating combined with irrigation represents a promising and environmentally sustainable thermo-reclamation technology capable of improving soil functioning and agricultural productivity, provided that long-term monitoring of soil water–salt regimes is maintained. Full article

Polycyclic aromatic hydrocarbons (PAHs), characterized by their high stability, are typical persistent organic pollutants that pose irreversible risks to human health. Conventional chemical oxidation methods exhibit limitations that hinder effective remediation in practice. In contrast, sulfate-radical-based advanced oxidation processes have emerged as promising alternatives, among which the heat-alkaline activation system for persulfate (PS) demonstrates distinct advantages. In this study, a heat-alkaline-activated PS system was established to investigate the degradation of PAHs in both simulated contaminated soils and coal chemical industrial site soils, as well as the modulatory effects of natural organic matter (NOM). Response surface methodology optimized critical experimental parameters to 12.53 mmol PS dosage, 60.31 °C reaction temperature, and a 1.55 CaO/PS molar ratio. Under these conditions, degradation efficiencies of 98.32% and 82.26% were achieved in simulated and field soils, respectively. Radical test experiments revealed a cooperative mechanism dominated by SO₄⁻• > •OH > O₂⁻• radicals, accompanied by auxiliary involvement of non-radical ¹O₂. Low concentrations of NOM plausibly facilitate degradation via a hypothesized electron transfer protective effect and boosted radical generation, whereas excessive NOM inhibits degradation through competitive consumption of reactive radicals. Density functional theory calculations identified preferred radical attack sites on the aromatic rings of PAHs and corroborated the degradation pathway involving aromatic ring oxidation, functional group addition, ring cleavage, and mineralization. QSAR-based theoretical toxicity predictions via T.E.S.T. suggested that the ultimate degradation products exhibit lower potential toxicity than parent PAHs. Experiments fill the knowledge gap regarding NOM-mediated regulation in heat-alkaline activated PS systems, and elucidate degradation mechanisms and toxicity evolution. Full article

High-wear-resistant iron-based clad layers demonstrate substantial application potential in aerospace, automotive, and industrial equipment due to their excellent mechanical properties and extended service life. Laser cladding has emerged as a pivotal technology for the additive manufacturing and repair of critical components, characterized by rapid cooling rates, narrow heat-affected zones, and dense microstructures. However, fabricating high-wear-resistant Fe-based clad layers remains challenging, particularly in achieving a trade-off among hardness, wear resistance, and toughness. Excessively high hardness often compromises toughness, increasing susceptibility to cracking and reducing service reliability, whereas insufficient hardness undermines functional performance and shortens service life. This review synthesizes recent advances in microstructural design, control, and optimization of high-wear-resistant Fe-based clad layers, focusing on powder alloying design, process parameter optimization, and post-cladding strengthening treatments. The strengthening mechanisms and performance characteristics of key alloying elements, specifically Cr, B, Nb, Mo, and Ti, are summarized, and the effects of laser power, scanning speed, and powder feeding rate on the microstructure and properties are systematically discussed. Furthermore, the influence of post-treatment processes, including turning, grinding, ultrasonic rolling, and heat treatment, on wear resistance enhancement is also addressed. Finally, future development directions for laser cladding of high-wear-resistant Fe-based clad layers are proposed. Full article

The high energy demand driven by industrial development has transformed the power system from a single energy source to multiple energy systems (MESs). These systems, which involve thermal generators, combined heat-and-power (CHP) units, electrolyzers, fuel cells, etc., with realistic forecast uncertainty, are very operationally challenged. This paper proposes a Distributionally Robust Optimization (DRO) based on a Wasserstein-metric ambiguity set, which simultaneously optimizes the annual maintenance schedules and short-term operational dispatch across MESs. The ambiguity set is constructed using joint samples of forecast errors for the three carriers’ demand, allowing for a data-driven worst-case distribution approach that mitigates the excessive conservatism typically associated with conventional robust optimization (CRO). The penalties are explicitly enforced for load and renewable energy curtailments across each of the MESs with source-specific value-of-lost-load coefficients. The Wasserstein radius is improved by sensitivity analysis, obtaining a θ value of 0.20 as the cost reduction radius for a 40% RES penetration. Five RES penetration levels are implemented here on the IEEE 39-bus New England network, with CHP, electrolyzer, fuel cell, thermal storage, and hydrogen storage. The DRO reduces the total annual system cost by 56% compared to CRO, while reducing the unbalanced energy. Full article

To address post-acidification, microbial contamination, and quality deterioration in fermented pickled mustard greens after fermentation, this study systematically evaluated the effects of thermal treatment on quality preservation, selected a preferred thermal processing condition from three kinetically designed treatments, and predicted product shelf life. Based on heat penetration curves and the thermal death kinetics of the target heat-resistant microorganism, Bacillus subtilis, three thermal processing conditions were established: 75 °C for 64 min, 85 °C for 19 min, and 95 °C for 17 min. The D-value of B. subtilis spores at 85 °C was 1.37 min, and the corresponding thermal treatments were designed according to a 2D reduction principle. HS-SPME-GC-MS analysis identified 84 volatile compounds, with isothiocyanates representing key contributors to the characteristic pungent aroma of mustard-based pickles. Sensory evaluation showed that the 85 °C treatment group achieved the best observed balance among pungency, refreshing aroma, mellow flavor, color, texture, and overall acceptability, whereas excessive heating at 95 °C promoted isothiocyanate loss and texture deterioration. During accelerated storage, the selected treatment inhibited post-acidification, maintained nitrite at a low level (<1 mg/kg), and delayed microbial and sensory deterioration. Integrating physicochemical indices, microbial populations, and sensory scores, the theoretical shelf life under refrigeration at 4 °C was predicted to be 170 days using the Q10 model. These findings provide practical guidance for selecting thermal processing conditions that balance microbial safety, flavor retention, and shelf-life extension in industrial fermented pickled mustard greens. Full article

Crack defects are prone to occur during MAG overlay remanufacturing of TBM cutter rings, thereby affecting the repair quality and service reliability of the remanufactured layer. In this study, longitudinal alternating magnetic field (LAMF) stirring was introduced into the MAG overlay remanufacturing process of H13 steel cutter rings to regulate molten-pool behavior and suppress crack defects. A molten-pool-scale sequentially coupled thermo-fluid-electromagnetic model was developed to compare the relative changes in the temperature and velocity fields with and without LAMF under identical MAG process parameters, heat-source input, material properties, and boundary conditions. In the model, the effect of LAMF was introduced through a Lorentz-force source term acting on the electrically conductive molten metal. The simulation results show that LAMF promoted heat redistribution within the molten pool, smoothed the thermal transition near the rear region of the molten pool, and reduced local heat accumulation. Meanwhile, LAMF modified the molten-pool flow pattern by weakening excessive flow along the welding direction and enhancing transverse circulation and vortex-induced mixing. Comparative overlay remanufacturing experiments were then conducted using a self-built magnetic-field stirring platform. Penetrant testing, X-ray inspection, metallographic observation, and industrial CT reconstruction were combined to characterize surface cracks, internal defects, and post-solidification microstructure. Compared with the non-LAMF condition, the maximum internal crack length decreased from 29.41 mm to 20.30 mm, corresponding to a reduction of 30.98%, and the crack-defect volume fraction decreased from 0.93% to 0.28%, corresponding to a decrease of 0.65 percentage points. The combined simulation and characterization results indicate that Lorentz-force-driven electromagnetic stirring improves the thermal-fluid conditions near the solidification front, thereby effectively reducing the formation tendency of solidification-related crack defects during MAG overlay remanufacturing. Full article

Radiant tube burners (RTBs) are widely used in industrial heat-treatment furnaces, yet the coupled effects of hydrogen co-firing and exhaust gas recirculation (EGR) on their thermal fields remain insufficiently understood. This study presents a three-dimensional CFD analysis of 28 operating conditions, spanning hydrogen fractions from 0 to 100% and EGR rates from 0 to 20% at a fixed excess air ratio of 10%. The model employs the eddy dissipation concept with a reduced two-step methane mechanism, detailed hydrogen kinetics, and a Discrete Ordinates radiation model with a weighted-sum-of-gray-gases approach. All cases exhibit splitting flames: hydrogen enrichment intrinsically raises the laminar flame speed above the flame morphological transition threshold, while in pure methane, radiative preheating increases the flame speed by 29%, eliminating the triangular flame mode. The volumetric temperature uniformity index peaks near 30% H₂, whereas EGR improves uniformity in hydrogen-rich cases but slightly degrades it in methane-rich conditions. Surface temperature uniformity is maximized at 20% EGR due to near-wall thermal blanketing. Thermal efficiency increases with hydrogen fraction, from 59.1% at 0% H₂ without EGR to 68.6% at 100% H₂ with 10% EGR, while higher EGR suppresses peak temperatures. These findings provide guidance for balancing energy efficiency and temperature uniformity in hydrogen-ready RTBs. Full article

Acrylamide (AA), a food processing contaminant and potential carcinogen, poses a significant health risk in heat-processed snacks, particularly for children. This study evaluates the efficacy of three pre-treatments: pulsed electric fields (PEFs), ultrasound (USN), and soaking for AA mitigation in popcorn (Zea mays everta). Using liquid chromatography–tandem mass spectrometry (LC-MS/MS), AA levels were quantified across nine treatment variations. All strategies significantly reduced AA formation (p < 0.0001), with soaking (20 min) and USN (20 min) achieving the highest reductions (>82% and 82%, respectively). High-intensity PEF (3 kV cm⁻¹, 300 kJ kg⁻¹) yielded a 71% reduction, though it showed lower reproducibility due to the kernel’s dense morphology. Crucially, while soaking and USN were superior in AA leaching, durations exceeding 20 min compromised popping expansion and sensory texture due to excessive hydration. These results define the critical processing window for industry, balancing toxicological safety with product quality. Full article

Hydrogen-rich shaft furnaces operated with coke oven gas (COG) represent an important low-carbon ironmaking route. Conventional porous-medium CFD models, however, do not explicitly resolve geometry-dependent burden descent or downward advection of solid sensible heat in variable-cross-section moving beds. To address this gap, a user-defined-scalar (UDS)-based pseudo-fluid moving-bed dual-temperature CFD framework is developed in this study. The framework couples geometry-dependent pseudo-solid kinematics, UDS-based transport of pseudo-solid species and sensible enthalpy, and a 12-step reduction-reforming-carbon reaction network on a fixed Eulerian mesh. It is applied to a 0.5 Mt·a⁻¹ industrial reactor through one reference case and three parametric groups covering solid descent velocity, cooling-side back pressure, and CH₄ content. Mesh-independence and mass-conservation checks indicate that the medium mesh is adequate for the intended trend-level assessment; the fine-to-medium deviations are 0.54% for DRI metallization, 0.23% for DRI outlet temperature, and 0.20% for top-gas temperature, with a net global mass residual of 1.53 × 10⁻⁶ kg·s⁻¹; the baseline DRI metallization (96.3%), carbon content (1.1%), and combined H₂ + CO utilization (29.45%) all fall within the reported ranges of the HBIS demonstration line and Energiron-ZR projects. As the descent velocity increases from 2.88 to 6.72 × 10⁻⁴ m·s⁻¹, DRI metallization drops from 98.0% to 79.4% and the outlet temperature rises from 313.3 to 719.4 K. Increasing the cooling-gas outlet back pressure from 60 to 100 kPa reduces the cooling-outlet excess flow from 1.49 to 0.11 kg·s⁻¹, indicating a dynamic gas-seal control between the two gas circuits, whereas raising the inlet CH₄ fraction from 10 to 23 vol% lowers the apparent CH₄ conversion from 29.5% to 18.5% and broadens the carbon-deposition zone. The framework offers a continuum basis for proof-of-concept and trend-level analysis of variable-cross-section hydrogen-rich moving-bed shaft furnaces. 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

In a calcined clay rotary cooler, the flow behavior and heat transfer characteristics of the granular bed are key factors determining the cooling efficiency. In this study, an Euler–Euler multiphase model coupled with the kinetic theory of granular flow (KTGF) was used to simulate the granular bed flow and heat transfer in a rotating drum of a rotary cooler. Unlike conventional large-particle beds, the 11 μm calcined clay particles interact more strongly with the gas phase, resulting in stratification and fluidization in the fine-particle bed. The effects of rotational speed, baffle configuration, and number of baffles on the flow and heat transfer behavior of the calcined clay granular bed were investigated. The results show that L-shaped baffles provide superior cooling, achieving a granular bed temperature and heat transfer coefficient (HTC) of 656.88 K and 151.15 W/(m²·K), respectively. At 2 rpm, the maximum temperature decrement and HTC increment are 5.73 K and 46.30 W/(m²·K), whereas excessive rotational speeds intensify bed fluidization. Additionally, increasing the number of L-shaped baffles has limited influence on expanding the fluidized region. With 12 L-shaped baffles, the temperature decrement peaks at 2.86 K and the HTC increment reaches a relatively high 33.27 W/(m²·K). This study provides a theoretical basis for the design and optimization of industrial-scale rotary cooling equipment for fine-particle beds. Full article