Search Results (857)

Ammonia is a cornerstone chemical for global food security and an emerging carbon-free energy carrier, yet its industrial synthesis via the Haber–Bosch process remains energy-intensive and carbon-emitting. Non-thermal plasma catalysis offers a promising decentralized alternative for nitrogen fixation under milder conditions, though the long-term structural stability of supported metal catalysts under harsh plasma environments remains a key open challenge. Plasma-assisted NH₃ synthesis was investigated using exsolution-derived Co-La₂O₃/Al₂O₃ and Ni-La₂O₃/Al₂O₃ catalysts in a pulsed (1 kHz at 50% duty cycle) microwave reactor operating at sub-atmospheric pressure (2–6 Torr) and 2.45 GHz. The catalysts were prepared by reductive H₂ treatment of LaCoO₃ and LaNiO₃ perovskite precursors, deposited onto Al₂O₃ pellets, triggering metal exsolution and generating metallic Co⁰ and Ni⁰ nanoparticles embedded within a La₂O₃/Al₂O₃ matrix. Catalytic performance was evaluated across a range of H₂/N₂ flow rates (200–400 cm³/min each) and microwave power inputs (0.6–0.7 kW average), using bare Al₂O₃ as a reference. Co-La₂O₃/Al₂O₃ outperformed both Ni-La₂O₃/Al₂O₃ and the Al₂O₃ reference under all tested conditions, reaching a maximum H₂ conversion of 2.39% and a peak productivity of 20.6 μmol/g_cata.h, attributed to the finer metal dispersion and smaller nanoparticle size achieved during Co exsolution from the LaCoO₃ lattice. Post-reaction characterization by TEM, XRD and N₂ physisorption confirmed the structural integrity of both spent catalysts. No bulk phase transformations were detected by XRD, while specific surface areas were retained above 93% of the initial one. Metals’ particle size slightly increased after plasma exposure, confirming the structural durability of catalysts. These results demonstrate that the exsolution mechanism confers meaningful sintering resistance under microwave plasma conditions, establishing exsolution-derived perovskite catalysts as a promising and durable platform for plasma-assisted nitrogen fixation. Full article

A building façade normally keeps the weather out, lets in daylight, allows ventilation, and shapes how a building looks from outside. This study asks whether it can also help generate electricity without giving any of that up. Solar chimney power plants (SCPPs) generate clean electricity from solar heat, but they have mostly been studied for open, land-abundant rural sites. Mounting one onto a façade instead risks the very things a façade is meant to protect: thermal comfort, natural ventilation, and architectural freedom. No prior study has looked at energy output, thermal behaviour, double-skin façade (DSF) operability, and architectural freedom together for solar chimneys integrated into high-rise buildings, and this is the gap this work addresses. We coupled solar chimney power plants with double-skin façades across five configurations, evaluated using Computational Fluid Dynamics (CFD) validated against the Manzanares pilot plant to achieve 3.3% for velocity and 3.0% for temperature. Using the DSF as both collector and absorber (Model 1) pushes power to its highest point, 78.7 kW, but it drives inner-façade air to 327.1 K and shuts off ventilation entirely. Confining the collector to the roof and upper chimney instead (Model 5) settles for a more modest 31.1 kW, but it preserves DSF ventilation over most of the façade height and keeps inner air below 305.8 K through the majority of that range, with only the uppermost portion becoming thermally unsuitable for natural ventilation. Weighing power, thermal load, ventilation, and façade freedom together in a composite score, Model 5 comes out as the preferred configuration under the adopted equal-weight multi-criteria assessment. A parametric study of height, irradiance, and ambient temperature for Model 5 produced design equations that, paired with a Random Forest climate forecast, benchmarked against three alternative algorithms and evaluated on a chronological hold-out set (city-level test R² up to 0.83 for irradiance and 0.94 for temperature), power a predictive framework for hourly-to-annual energy output at any height and city, demonstrated here for seven cities across five continents. Full article

With the rapid advancement of space-based laser weapon technologies, on-orbit safety of spacecraft such as satellites is confronted with severe laser threats. To meet the demands for film system optimization and reliability improvement of thin films integrating space laser protection and thermal control functions, this study takes the Graphene/Ag/Al₂O₃/SiO₂/ITO multilayer thin film structure as the research object. Combined with the space alternating high-low temperature environment and the action of ultra-high-density transient directional heat flux, systematic simulation research on the evolution laws of temperature and stress fields inside the multilayer thin films under laser irradiation in alternating space high-low temperature environments is carried out via COMSOL Multiphysics, and the influencing mechanisms of ambient temperature and laser operating parameters on thermal stress and temperature distribution are revealed. The simulation results demonstrate that the thin film structure reaches thermal equilibrium within several seconds under a given transient directional heat flux. As laser power rises, the peak temperature of each layer increases nonlinearly and the time required to reach thermal equilibrium shortens. The laser heat flux density acts as the dominant factor governing the temperature and thermal stress distribution. Under alternating space high-low temperature conditions, the thermal stress of the thin film varies approximately linearly with temperature while the overall stress magnitude remains low, and thermal stress is mainly concentrated in the Al₂O₃ layers. Laser loading exerts a remarkable impact on film thermal stress: the amplitude of thermal stress in all film layers rises synchronously with increasing laser power, and interlayer temperature gradients as well as stress concentration are further intensified. The stress growth of Ag and Al₂O₃ layers is the most significant, which can be attributed to the synergistic effect of interlayer thermal expansion coefficient mismatch and temperature gradients. The alternating high-low temperature and laser irradiation experiments indicate that the maximum temperature and maximum stress borne by the muti-layer film under alternating temperatures ranging from −150 °C to 150 °C and laser irradiation of 200 W/cm² will not lead to macroscopic failure behaviors and degradation of thermal control performance. Full article

The importance of accurate and fast forecasting of wind speed is critical for guiding investment decisions, grid integration of wind power plants, and dispatch management. However, due to surface smoothness and the effects of thermal processes, wind-speed time series obtained from onshore and offshore sites have very statistically and dynamically distinct characteristics in terms of volatility, non-stationarity, autocorrelation, and noise components. This study proposes a Sinusoidal Representation Network (SIREN)-based framework to provide accurate, fast, and direct multi-horizon wind-speed forecasting for both onshore and offshore wind farms. Two datasets of onshore and offshore wind speeds, which have long durations and data continuity, are used to assess the performance of the suggested approach from very-short-term to long-term forecasting horizons. Both of the datasets use Savitzky–Golay filters and moving medians to reduce short-term noise and sudden spikes and winsorization and Hampel filters to limit the effect of outliers. Additionally, robust scaling is done to ensure stability of the scales of the variables, while log transformation is applied to counteract the problem of skewness and variation in the data distribution. The SIREN model is trained, validated, and tested independently for each forecast horizon, corresponding to times ranging from 5 min to 30 days. Ablation and sensitivity analyses are conducted to evaluate the effect of the parameters used in the model on forecast performance. In addition, comparative analyses incorporating traditional time series, and ML and DL techniques are conducted to more comprehensively evaluate the model’s performance. The obtained graphical and numerical results have revealed that the proposed SIREN approach is a highly accurate and computationally convenient alternative wind-speed forecasting method that can be flexibly adapted to different time resolutions and forecast horizons in both onshore and offshore systems. Full article

Oxalis tuberosa (oca) is an underutilized Andean tuber with potential as an alternative starch source. This study compared native starches isolated from locally recognized yellow, pink, and black oca materials using compositional, structural, morphological, hydration, pasting, and thermal analyses. All starches exhibited B-type crystallinity but differed significantly in their measured characteristics. Black oca starch had the highest amylose content (28.1%), relative crystallinity (35.8%), median granule diameter (22.8 μm), and FTIR 1047/1022 ratio (1.36). Conversely, pink starch showed the highest swelling power at 90 °C (17.5 g g⁻¹), peak viscosity (3900 cP), and gelatinization enthalpy (12.83 J g⁻¹), compared with 10.9 g g⁻¹, 2350 cP, and 7.61 J g⁻¹, respectively, for black starch. The ordering of DSC parameters did not parallel XRD-derived relative crystallinity, indicating that relative crystallinity alone did not explain the thermal behavior. The contrasting functional profiles suggest that pink starch warrants further evaluation for applications requiring high hydration and viscosity development, whereas the lower RVA breakdown of black starch may be advantageous where resistance to viscosity loss during heating and shear is required. These findings demonstrate starch-level variation among the three local oca materials; however, application performance requires formulation-level validation, and broader multi-location and multi-harvest studies are needed to establish the stability of these characteristics. Full article

Conventional anaerobic digestion (AD), despite its proven efficiency in wastewater treatment, faces limitations due to energy requirements and extended hydraulic retention times, with methane yields from waste-activated sludge rarely exceeding 50% of the stoichiometric maximum at retention times of 20 days or more and with the resulting biogas containing 50–75% methane. It also has a constrained capacity for high-grade resource valorization except energy in the form of methane-enriched biogas. This review focuses on bioelectrochemical systems (BES) and hybrid configurations as promising alternatives for sustainable wastewater management. BES mechanisms, including microbial fuel cells (MFC), microbial electrolysis cells (MEC), and microbial electrosynthesis (MES), are analyzed in detail, with emphasis on their capacity to directly convert organic pollutants into electricity or high-value chemicals (hydrogen, acetate) with minimal external energy input. Key advantages include potential electrical energy production, significantly reduced excess sludge production, and high level of waste mineralization. Reported performance reaches power densities of 2203 and 4990 mW/m² for sludge-fed microbial fuel cells and up to 26,680 mW/m² in algae-assisted configurations, chemical oxygen demand (COD) removal of up to 92%, and excess sludge production of 0.09 g/g COD against 0.159 g/g COD for anaerobic digestion treating the same stream. Limitations in terms of scalability and capital costs remain barriers to industrial implementation. Special attention is given to hybrid configurations integrating BES with AD through direct interspecies electron transfer (DIET), which accelerates biodegradation kinetics and enhances resource recovery pathways; compiled MEC-AD data report methane increases of about 3–228% over unpolarized controls, and in a 1.7 L reactor treating alkaline-thermally pretreated waste-activated sludge, the optimum of 0.6 V raised the methane yield from 213.2 ± 9.5 to 308.7 ± 5.9 mL CH₄/g COD removed. These integrated approaches close material and energy cycles, enabling the simultaneous recovery of energy, nutrients (N, P), and bio-chemicals, transforming wastewater treatment plants into zero-waste biorefineries aligned with circular economy principles. Full article

This study investigated a high-temperature heat pump for industrial steam production at 200 °C. Considering refrigerant thermal degradation at elevated temperatures, R1336mzz(Z) was selected because of its thermal stability. Two systems were analyzed: a flash tank (FT) cycle producing steam using a water valve and flash tank, and a steam generator (SG) cycle directly generating steam in the gas cooler. Unlike previous studies focusing primarily on cycle-level thermodynamic performance, this study systematically compares two steam production configurations for a 3 MW-class HTHP by considering heat pump–steam loop interactions and further evaluates their economic and environmental feasibility through LCC and LCCP analyses. Applying an internal heat exchanger reduced the operating pressure and increased the heat pump coefficient of performance (COP) by up to 13%, depending on the pressurized water temperature. In the FT cycle, lowering the valve outlet temperature from 180 °C to 150 °C increased the heat pump COP to a maximum of 3.06. However, the additional mechanical vapor recompression (MVR) power limited the overall system COP to 2.29–2.44. In the SG cycle, the system COP ranged from 1.94 to 2.54 according to the saturated water temperature at the gas cooler inlet, although operation at lower water temperatures approached the critical region, resulting in a narrower operating margin. LCC and LCCP analyses showed that replacing conventional boilers with heat pumps reduced operating costs by 26–59%, depending on regional energy prices, with payback periods of 2.27–8.76 years. Heat pump adoption also reduced life cycle climate impacts by 13–72%. These results demonstrate that high-temperature heat pumps can provide an economically and environmentally viable alternative for industrial steam production at 200 °C. Full article

Wireless Power Transfer (WPT) has emerged as a compelling alternative to wired charging; however, efficiency and safety are highly dependent on magnetic field distribution and leakage. This work presents a compact MEMS–based magnetic field induction sensor, including its design, fabrication, and electrical characterization, for real-time diagnosis in WPT systems. The sensor employs a Ni/Cr metallic inductor fabricated on a SiO₂ substrate using standard photolithography and occupies a footprint of 5 mm × 5 mm. The device is electrically characterized through impedance, quality factor, and frequency response measurements, followed by experimental validation using an industry-standard wireless charging system and dedicated signal-conditioning circuitry. The results from inductive coupling simulations, performed with the Magpylib Python library, align with experimental data showing that the sensor accurately follows theoretical magnetic field decay, detecting AC signals between 40 mV and 140 mV with a functional limit of 30 mm. Furthermore, experimental characterization through spatial mapping successfully identifies magnetic leakage hot spots, while thermal validation via infrared thermography correlates these magnetic readings with localized temperature increases. This integrated approach supports EMC optimization and thermal risk mitigation, providing a low–cost and effective diagnostic tool for enhancing safety and performance in WPT applications. Full article

Battery-electric rail vehicles are a sustainable alternative for diesel-powered vehicles on tracks without catenary. However, the energy demand to heat and cool the cabin limits the vehicle range, and the applied synthetic refrigerants are environmentally harmful. Therefore, this paper studies how energy demand and load on the battery in battery-electric rail vehicles can be reduced using heat pumps with natural refrigerants and efficient thermal management. A heat pump and thermal car body model are developed and validated, which calculate the energy demand in battery-electric rail vehicles. In these models, an optimized thermal management strategy is implemented, which changes the cabin set-point temperature based on catenary availability. For a two-car battery-electric rail vehicle in the climate zone II of Central Europe, the annual thermal energy demand is up to 110 MWh. The application of a heat pump with R290 (propane) can reduce the annual electrical energy demand for heating and cooling by up to 55%. The load on the battery can be mitigated further with the optimized thermal management strategy, reducing the equivalent full cycles by 3%. Overall, the heat pump operation and efficient thermal management strategy lead to higher vehicle range and flexibility in daily operation, increasing the acceptance of battery-electric rail vehicles. Full article

Fuzzy multi-criteria decision-making is important for technology assessment when expert judgments contain uncertainty, hesitation, and inconsistent evidence. This study develops a T-Spherical Fuzzy-Valued Neutrosophic Set (T-SFVNS)-based MEREC-EDAS framework for evaluating low-carbon cooling and energy-management technologies for data centers. Expert linguistic assessments are represented by T-Spherical Fuzzy-Valued Neutrosophic Numbers and aggregated before a score function is used at the explicit scalarization boundary. Standard MEREC then derives objective criterion weights from criterion-removal effects, and standard EDAS ranks alternatives by their positive and negative distances from the average score profile. The application evaluates nine technologies against ten criteria using assessments from thirty domain specialists. The corrected MEREC calculation assigns the greatest weights to carbon reduction potential (0.127), electricity demand reduction (0.125), maintenance complexity (0.124), operational cost efficiency (0.123), and cooling efficiency (0.123). The final ranking is Direct-to-Chip Liquid Cooling, Liquid Immersion Cooling, AI-Enabled Energy Management, Water-Side Free Cooling, Free-Air Cooling, Rear-Door Heat Exchanger Cooling, Hot/Cold Aisle Containment, Renewable-Powered Cooling, and Thermal Storage-Assisted Cooling. Weight perturbation, q-parameter, leave-one-expert-out, alternative-deletion, dominated-alternative, and multi-method comparisons show that the leading tier is robust, although the exact order of the two liquid-cooling technologies is sensitive in some scenarios. The findings provide a transparent and reproducible decision-support basis while explicitly acknowledging the information compression and rank-reversal limitations of score-based MCDM. Full article

This paper reviews recent advances in integrated circuits for resonant wireless power transfer (WPT) systems in biomedical implants, with emphasis on resonant compensation networks and receiver-side power conversion. In these systems, a compact receiver coil must harvest attenuated alternating current (AC) power through biological tissue and convert it into a safe, efficient, and regulated direct current (DC) supply for implantable electronics. Limited coil size, weak coupling, load variation, and thermal safety constraints have driven the evolution from passive rectifiers to active and regulated rectifiers with delay-compensation techniques. This review first introduces the operating principles of resonant WPT links and compares series–series, series–parallel, parallel–series, and parallel–parallel compensation topologies in terms of output characteristics and implant suitability. It then summarizes passive, cross-coupled, active full-wave, delay-compensated, and regulated rectifiers. Finally, design guidelines are provided for selecting compensation and rectifier architectures according to power level, coupling condition, operating frequency, integration complexity, and regulation requirements. Full article

Liquid-hydrogen fuel-cell propulsion is a promising option for reducing the climate impact of short-range aviation, but its aircraft-level feasibility depends on the concurrent integration of cryogenic storage, megawatt-class propulsion systems, and thermal management. This paper presents an integrated conceptual design and technology-sensitivity assessment of a 101-passenger liquid-hydrogen fuel-cell aircraft, targeting a 1000 nmi design range and a 2040 entry into service, framed within the European Union FAME project. A JPAD-based aircraft sizing framework is coupled with a surrogate model for cryogenic tank sizing to investigate how selected hydrogen-subsystem characteristics propagate, through mission-fuel and tank-sizing convergence loops, to configuration-level performance and compliance with top-level aircraft requirements. The storage-system trade study identifies 2.0 bar as the most favourable sampled tank venting pressure; relative to the other investigated pressure levels, this solution reduces MTOM and design-mission block fuel by up to 8.1% and 9.2%, respectively. The propulsion-architecture study selects a four-engine layout as the best compromise between one-engine-inoperative performance, spanwise structural relief, nacelle drag, and mission fuel consumption, yielding a 2.6–2.7% lower MTOM and a 3.5–3.7% lower design-mission block fuel than the two- and six-engine alternatives. A technology-sensitivity matrix spanning 51–55% fuel-cell efficiency and 60–100% cooling-line speed recovery reveals a non-linear increase in installed power, aircraft mass, and hydrogen consumption as either parameter deteriorates. For the fixed-geometry FAME baseline, the onset of multiple TLAR violations occurs as speed recovery falls through approximately the 70–80% region, depending on fuel-cell efficiency. Within the assumptions of the present model, maintaining fuel-cell efficiency at or above approximately 53% and cooling-line speed recovery above this transition region therefore represents an approximate feasibility condition. Full article

The large-scale integration of photovoltaic generation into distribution grids has introduced significant operational challenges, including voltage excursions, reverse power flows, and increased variability. Battery energy storage systems (BESSs) offer a versatile solution by providing coordinated active- and reactive-power support. However, their scheduling in active distribution networks is challenging because of the non-convex alternating-current (AC) power-flow equations, the nondifferentiability of battery-degradation modeling, and uncertainty in renewable generation and demand. This paper proposes a two-stage methodology for the day-ahead operation of BESSs in ADNs. In the first stage, parallel particle swarm optimization (PPSO) determines the hourly active- and reactive-power schedules of the BESS units. In the second stage, a matrix-based multi-period AC power flow based on successive approximations evaluates the schedules and verifies voltage, thermal, converter-capability, and state-of-charge (SoC) constraints. A rainflow-counting degradation model is incorporated into the objective function to account for cycling and calendar aging costs. The methodology is assessed through ablation analyses comparing active-power-only and coordinated P–Q dispatches, degradation-unaware and degradation-aware scheduling, and serial and parallel PSO implementations. It is validated on modified 33-, 69-, and 136-node systems under deterministic and uncertainty-based operating conditions, including 100 demand and PV-generation scenarios. PPSO is compared with parallel versions of the adaptive Jaya algorithm (AJAYA), genetic algorithm (GA), multi-verse optimizer (MVO), salp swarm algorithm (SSA), grey wolf optimizer (GWO), and vortex search algorithm (VSA), using operating-cost reduction, computational time, solution variability, feasibility indicators, BESS lifetime, and weekly cost analysis. Additionally, exact one-sided Wilcoxon signed-rank tests with Holm adjustment are used to assess the statistical significance of the economic differences between PPSO and the benchmark methods. Results show that PPSO provides the lowest or most competitive operating costs and the shortest computational time in the evaluated cases, while all network and storage constraints remain satisfied. Full article

This study directly compares a photovoltaic (PV)-powered vapor-compression chiller with a solar-thermal-driven absorption chiller for localized cooling of the tomato crop zone in a 1536 m² smart greenhouse under a hot-arid climate. The principal contribution is a controlled system-level comparison of two solar-cooling pathways under the same greenhouse load, solar-aperture area, terminal equipment, rated cooling capacity, and crop-zone temperature-control constraints. The previously validated greenhouse model was transitioned from EnergyPlus 8.9 to Version 23.1, after which the two alternative plants were connected to the same base model. Base-case annual simulations produced nearly identical chiller cooling energy (1669.3 and 1668.9 MWh) and was only 4 and 5 h above 28 °C. The PV-powered system required 101.6 MWh of net grid electricity, whereas the absorption system used 202.3 MWh of electricity and 253.2 MWh of natural gas and achieved an 84.23% solar fraction. Static operational primary energy was 331.2 and 912.7 MWhPE, respectively; HSDH28 was 0.50 and 0.81 °C·h; and peak grid import was 113.46 and 63.61 kW. The absorption case additionally required 10,103.6 m³/yr of cooling-tower makeup water. Storage/EMS sensitivity changed the absorption solar fraction from 58.17% to 88.30% and natural-gas use from 187.7 to 674.0 MWh/yr without materially changing cooling service. Matched 50–100 W/m² daytime latent-load sensitivity increased annual cooling by 14.7–28.8%. At the 100 W/m² bound, HSDH28 increased to 49.32 °C·h for PV and 8.06 °C·h for absorption, while the principal energy–infrastructure trade-off remained: static primary energy was 712.4 versus 1354.2 MWhPE and peak grid import was 137.46 versus 63.96 kW. A bounded hourly primary-energy-factor stress test did not reverse the technology ranking, and balanced TOPSIS scores were 0.766 for PV and 0.234 for absorption. The results show that PV vapor compression minimizes operational primary energy and cooling-water use, whereas solar-thermal absorption reduces electrical peak demand and shows greater thermal-control resilience at the highest tested latent-load bound. Full article

Magnetothermally responsive nanocarriers represent a promising platform for spatio-temporally controlled drug delivery by combining alternating magnetic field (AMF)-induced heating with thermally triggered cargo release. Among the available architectures, magnetite-core/mesoporous-silica-shell (Fe₃O₄@mSiO₂) nanoparticles functionalized with thermoresponsive polymer gatekeepers are particularly attractive. These systems integrate a magnetic heat source, a mesoporous drug reservoir, and temperature-dependent control of pore accessibility. This review examines the fundamental principles of magnetic hyperthermia, including heat-generation mechanisms, specific absorption rate (SAR), intrinsic loss power (ILP), AMF parameters and safety, and the interplay between Néel and Brownian relaxation. It also critically discusses core–shell synthesis and architecture, drug-loading strategies, PNIPAM-, PNVCL-, and other LCST-type gatekeepers, and the physicochemical characterization required to validate the complete nanocarrier. Evidence for combined magnetic hyperthermia and chemotherapy is assessed together with hemocompatibility, immunogenicity, oxidative stress, biodistribution, degradation, long-term retention, and clearance. Although promising magnetothermal release and therapeutic effects have been reported, evidence remains dominated by in vitro studies, with limited in vivo validation. Current clinical experience concerns locally administered iron-oxide hyperthermia rather than complete thermoresponsive Fe₃O₄@mSiO₂ drug-delivery systems. Translation will require standardized magnetothermal and release testing, reproducible scale-up, validated sterilization and endotoxin control, component-resolved pharmacokinetics, and integrated development of the nanocarrier and AMF applicator. Full article