Search Results (2,428)

The Controllable Line-Commutated Converter (CLCC) integrates fully controlled and semi-controlled devices to mitigate commutation failure. However, its application in large-capacity HVDC systems is constrained by the limited current-carrying capability of fully controlled valves in the main branch. To address the HVDC requirements under high-current conditions, this paper proposes a high-reliability cascaded H-bridge CLCC (H-CLCC) valve topology. The proposed topology employs a dual-path conduction mode for H-bridge sub-valves, reducing electrical stress on devices and enabling modular scalability. A redundant configuration, in which cascaded H-bridges are paralleled with bypass thyristors, allows faulty sub-modules to be rapidly bypassed, ensuring continuous operation. An analytical model based on the Laplace transform is developed to reveal the relationship between capacitor voltage and turn-off current, providing guidance for capacitance design. PSCAD/EMTDC simulations verify that the H-CLCC valve effectively suppresses commutation failure via active commutation, even under severe AC-side faults with currents up to 8 kA. Device-failure simulations further demonstrate strong self-healing capability, ensuring sustained forced commutation under local faults. This work provides a foundation for high-reliability UHVDC converter valve design. Full article

Poultry meat and eggs are high-quality protein sources, but thermal processing alters their nutritional and functional attributes. Emerging non-thermal and novel processing methods, such as high-pressure processing, ultrasound, pulsed electric fields, cold plasma, moderate electric fields, magnetic fields, ozone treatment, and pulsed light, are increasingly popular as substitutes. This review examines the effects of nonthermal and novel processing technologies on poultry meat and egg proteins. The review focuses on the interrelationship among protein structure, functionality, and digestibility, with emphasis on the mechanism underlying structural modification, altered intermolecular interactions, and controlled protein unfolding. Under optimized conditions, nonthermal technologies can maintain protein integrity and improve functionality such as water-holding capacity, emulsification, gelation, and tenderness in poultry meat. In egg proteins, non-thermal technologies improve solubility, emulsification, foaming, and gelation through structural modification, intermolecular interactions, and controlled unfolding, thereby exposing enzymatic cleavage sites and enhancing digestibility. Evidence exists for enhanced proteolysis by peptide release and amino acid availability in nonthermal treatments, whereas studies on poultry meat remain limited. This review integrates existing evidence and critical gaps in interpreting structure–functionality–digestibility interrelation, and highlights the potential of nonthermal technologies for producing poultry-derived foods with higher functional quality and nutritional value. Full article

High renewable penetration makes imbalance settlement inseparable from the physical decisions governing reserve procurement and flexibility activation. This paper develops a decision-focused learning-based optimization framework that trains renewable-deviation and flexible-resource deliverability representations through downstream dispatch, reliability, and settlement consequences. The mathematical contribution is a settlement-aware learning objective that couples learned uncertainty, resource-time credible-capacity certification, network-constrained multi-stage dispatch, and counterfactual marginal-contribution allocation while retaining an exact revenue-adequacy identity. The 33-node Zhangjiakou-type regional case uses 15 min intervals and comprises five resource classes: independent storage, data-center flexibility, industrial adjustable load, commercial demand response, and electric-vehicle aggregation. Relative to a fixed-ratio reserve rule, the proposed method lowers the regional balancing cost from 950 to 618 thousand USD (34.9%), achieves 97.8% renewable accommodation, limits the shortage probability to 0.7%, and attains a settlement-fairness index of 0.92. The framework solves a 500-asset instance in 118 s. External validation uses 4027 half-hour observations from the 2025 Elexon/BMRS market, including measured wind and solar output, day-ahead forecasts, load, imbalance prices, and procured-reserve prices. On the 1487-interval December test set, the proposed model reduces the replay cost from 2953.3 to 2598.2 thousand GBP (12.0%), decreases the shortage-interval frequency from 4.64% to 1.28%, and reaches 99.74% renewable accommodation. Comparisons with forecast-then-optimize, Wasserstein distributionally robust optimization, off-policy reinforcement learning, and graph-based behavioral cloning establish that the improvement comes from jointly learning which uncertainty matters for dispatch and which flexible capacity is deliverable. Full article

Digital identity and battery-passport systems can make electric-vehicle battery lifecycle records traceable, but traceability alone does not guarantee verifiable evidence or physical recycling compliance. We develop a normative two-stage Stackelberg model in which a regulator chooses audit intensity and verified incentives and a representative obligated firm jointly chooses pre-verification evidence quality and recycling compliance. The benchmark is stress-tested under reduced eligibility-confirmation effectiveness, alternative evidence–recycling interaction, decentralized manufacturer–recycler decisions, and implementation costs. Baseline traceability can leave evidence quality at the reporting floor and compliance incomplete, while additional responsibility exposure can conditionally increase recycling compliance while reducing evidence quality. Coordinated verified incentives improve both decisions and welfare in the benchmark complementarity domain. At zero eligibility-confirmation effectiveness, the fixed positive-rate package can become marginally welfare-inferior under finite capacity; adverse interaction can reverse a cross-effect, decentralization creates coordination underinvestment, and high payment or startup costs create single- or no-positive-payment regions. The model is therefore a forward-looking governance analysis rather than an empirical evaluation or legal calibration of current Chinese or European Union rules. Full article

To address the limited cooling range of ventilation in deep, high-temperature development headings and the lack of coordinated design between coil-based cooling and the ventilation system, this study proposes a coupled “twin-forcing–coil” cooling scheme. Building on conventional overlap (forcing–exhausting) ventilation, a rear-mounted second forcing duct is added to the conventional overlap (force–exhaust combined) auxiliary ventilation system, forming a dual-duct forcing, single-exhausting configuration—hereafter termed the “twin-forcing–single-exhausting” (TFSE) system—that provides a booster (relay) air supply to mitigate the along-path attenuation of cooling capacity and the short-circuiting of cold air; an in situ heat-exchange coil wall further provides supplementary cooling where ventilation-based temperature control weakens. Using a development heading at the 790 m level of a metal mine in Yunnan as the engineering background, a three-dimensional numerical model coupling the roadway, ventilation system, and coil wall was established and validated against nine field monitoring points, showing average relative errors of approximately 1% for temperature and 2–3% for humidity, comparable to the measurement uncertainty of the field instrumentation. Because the numerical model does not account for evaporative and condensation phase-change processes, two supplementary development headings with standing water at the face were used for validation; results showed that model error increases with water accumulation and heading length, indicating the model’s applicability is limited to conditions with intact surrounding rock and minimal seepage. Six operating cases were designed with duct placement and coil spacing as variables. Results show that single-duct ventilation cooling decays markedly beyond 30 m from the face, whereas twin-forcing booster (relay) air supply effectively extends the cooling range, reducing the 30–70 m section temperature by 2.7–2.9 K; the second duct should be positioned where the first duct’s cooling capacity begins to attenuate but is not yet depleted. Based on only two spacing configurations tested (10 m and 15 m), coil-staggered spacing showed limited effect on cooling performance under the field conditions examined; this preliminary finding requires validation across a broader range of spacings. Among the chilled-water conditions tested, an inlet temperature of 280.65 K and a flow velocity of 0.5 m/s offered a reasonable trade-off between cooling uniformity and economic efficiency. Under the boundary conditions and equipment parameters of this case, energy consumption estimates further indicate that the cooling effect per unit electricity consumption of twin-forcing ventilation is roughly 6–8 times that of coil-based cooling, primarily due to pumping losses over the ~240 m chilled-water delivery distance. This energy penalty indicates that coil-based cooling is better suited as a localized, short-distance supplementary measure rather than as a means of extending the cooling range over long distances. Full article

Reliable pack-level battery systems capable of safely handling instantaneous high-C-rate discharge above 10C during take-off, climb, and hovering are required for the commercialization of urban air mobility (UAM) aircraft. However, pack-level studies on wide-range C-rate characteristics of battery systems for UAM applications remain very limited, and most previous studies have been restricted to single-cell experiments or battery-pack simulations. In this study, a 24S1P test battery pack using nickel–cobalt–manganese (NCM) pouch cells, with a nominal voltage of 88.8 V and a capacity of 22 Ah, was designed and fabricated. A two-level battery management system (BMS) based on the LTC6803G-4 was also developed. To evaluate the charge–discharge characteristics of the battery system, constant-current discharge tests were conducted under five conditions ranging from 0.2C (4.4 A) to 10.68C (235 A), and charging tests were performed over the range of 0.2C–2C. The discharge test results showed that the capacity retention remained within 97.5–100.0% in the 1C–5C range, confirming excellent power capability. Continuous discharge operation was confirmed at 10.68C, the maximum discharge condition considered for vertical take-off and climb. Under this condition, the capacity decreased to 16.26 Ah, corresponding to 74.2% of the rated capacity, owing to internal-resistance-induced voltage drop, electrochemical polarization, and early attainment of the cut-off voltage. The Peukert exponent was estimated to be 1.113. An apparent pack-level direct-current internal resistance (DCIR) of approximately 40.3 mΩ was estimated from the initial voltage-drop analysis under different discharge-current conditions. In addition, the maximum temperature during 10.68C discharge was measured as 55.1 °C, providing a thermal margin of 4.9 °C relative to the operational temperature limit of 60 °C adopted in this study. Finally, a 24S4P battery system with a capacity of 88 Ah, consisting of four 24S1P battery packs connected in parallel, was installed in the VS-210, a 210 kg-class maximum take-off weight (MTOW) eVTOL aircraft. An in-flight test was conducted by repeating six take-off–hovering–landing cycles during a total test session of 15 min 20 s, and a stable propulsion power supply was maintained throughout all flight cycles. This study provides experimental baseline data for the design and preliminary safety assessment of high-power battery systems for UAM applications by presenting both the electrical and thermal characteristics of a 24S NCM battery pack over a wide discharge-rate range of 0.2C–10.68C and in-flight eVTOL data. Full article

Carbon pricing is jurisdictional, while proof-of-work cryptocurrency mining is a highly mobile electricity load. We examine whether daily power-sector emissions display a cross-regional and distributional pattern consistent with short-run emissions displacement. Using daily observations covering calendar years 2019–2025 (with a boundary observation on 1 January 2026; N = 2550 after transformation and cleaning), we estimate quantile regressions for the EU27, the Russian Federation and the rest of the world using the interaction between Bitcoin returns and European carbon-allowance returns. The focal Russian lower-tail interaction is positive (q10 beta = 0.0662); OLS and dynamic specifications remain positive, and a 1000-replication pairs bootstrap gives p = 0.0077. The association survives a trading-day-only sample, calendar and persistence controls, and a seven-lag specification, while randomised-carbon and non-power-sector placebo outcomes are null. However, the coefficient loses conventional significance without Winsorisation, the May-2021 Chinese-ban timing prediction is not supported, and a direct EU27-minus-Russia substitution diagnostic is null. Quantile-on-quantile estimates place the largest Russian Bitcoin-return coefficients in high-carbon-price, low-emission states, but remain descriptive. Because the design does not observe mining capacity moving across jurisdictions and the available full-sample Russian emissions series is national rather than subnational, the evidence supports a leakage-consistent operational association rather than proof of physical relocation or a broad causal effect of EU carbon pricing. Full article

Large-scale renewable energy bases with high penetration of renewable energy are facing increasing challenges related to renewable energy curtailment. Concentrated solar power plants with thermal energy storage can provide dispatchable power output, while electric heaters offer a promising pathway for converting surplus renewable electricity into useful thermal energy. In this study, a photovoltaic–wind turbine–electric heater–concentrated solar power integrated energy system with a fixed CSP-EH configuration is investigated. The electric heater is introduced as the key electrical-thermal coupling device, which recovers otherwise curtailed photovoltaic and wind power and injects the converted thermal energy into the heat transfer fluid loop of the concentrated solar power plant. A mixed-integer linear programming model is developed to optimize the coordinated scheduling and evaluate different PV/wind capacity mixes under fixed CSP and electric-heater capacities. Results show that, under the fixed capacities of 100 MW concentrated solar power and 150 MW electric heater, the PV/wind capacity mix of 500 MW photovoltaic and 400 MW wind power achieves the best overall performance among the studied cases. Under different typical-day conditions, the electric heater recovers surplus renewable electricity, with recovery rates ranging from 16.06% to 20.21%. The proposed electric heater–concentrated solar power coupling mechanism transforms curtailed renewable electricity into dispatchable thermal energy, thereby reducing renewable energy curtailment, enhancing thermal-side flexibility, and improving the operating revenue of large-scale renewable energy bases under the studied PV/wind capacity-mix scenarios. Full article

Aqueous zinc-ion batteries (AZIBs) have garnered extensive attention owing to their high theoretical capacity, cost-effectiveness, and intrinsic safety. However, the practical deployment of AZIBs is severely hindered by deleterious side reactions, including surface corrosion, hydrogen evolution, and uncontrollable dendrite growth on the metallic Zn anode. In this work, we propose a simple one-step immersion strategy to in situ construct a ZnMoO₄ (ZMO) protective coating on the Zn electrode. Mechanistically, the ZMO layer with polar surfaces exhibits a preferential adsorption affinity towards water molecules and Zn²⁺ ions. This synergistic adsorption behavior serves a dual function: it effectively excludes active water from the electrode surface to suppress hydrogen evolution, and simultaneously, the strong interaction with Zn²⁺ lowers the desolvation energy barrier, facilitating rapid Zn²⁺ desolvation at the interface. Furthermore, the resulting ZMO coating promotes a homogenized surface electric field and provides abundant nucleation sites, thereby guiding uniform Zn deposition and effectively mitigating dendrite formation. Consequently, the ZMO-modified Zn anode delivers significantly enhanced electrochemical reversibility and long-term cycling stability. This work provides a cost-effective and industrially viable surface engineering strategy to tackle the fundamental challenges of Zn anodes, paving the way for the commercialization of high-performance AZIBs. Full article

Lithuania is a success case in the prosumer-driven deployment of distributed solar photovoltaic (PV) systems. Supported by generous investment subsidies and a net-metering scheme, behind-the-meter solar PV capacity expanded at an exponential rate. This study examined how the rapid growth of prosumer-based solar PV generation has affected the broader electricity market, prosumers, and electricity suppliers. Using electricity market data, the research evaluated impacts on electricity market price formation, electricity suppliers’ profits, prosumer costs, and the prosumers’ investment decisions. The results indicate that, during the early stages of deployment, distributed solar PV systems improved market outcomes by reducing average electricity market prices and enhancing consumer welfare. However, as the installed solar PV capacity increased rapidly, structural imbalances emerged. High solar output during low-demand periods contributed to increased electricity market price volatility, including frequent close-to-zero and even negative price episodes, while periods of low solar availability—particularly during windless winter days—were associated with sharp price spikes. These dynamics generated negative revenue streams for electricity suppliers and weakened investment signals for market-based generation projects. While prosumers, who are predominantly middle- and upper-income households, benefited substantially from reduced electricity costs and stable returns, the findings suggest that non-participating consumers, including vulnerable households, may have faced higher electricity costs. The study highlights the need for adaptive support mechanisms and market design reforms to ensure an equitable and investment-friendly energy transition. Full article

This research presents a comprehensive diagnosis of Ecuador’s electricity generation (2003–2024), focusing on structural vulnerabilities, fuel dependence, and Greenhouse Gas (GHG) emissions from electricity generation. The technological composition of the grid, including installed and effective capacity, as well as the share of fossil and organic fuels, is analyzed to construct a coherent analytical framework. GHGs (i.e., CO₂, CH₄, and N₂O) are estimated from fuel consumption in Non-Conventional Renewable Energy (NCRE) and Non-Renewable Energy (NRE), in accordance with the 2006 IPCC Guidelines. Conversion to CO₂ equivalent utilizes the AR5 GWP factors, in agreement with AR6. The results present annual series for each gas and their corresponding CO₂ equivalents, showing that NREs dominate the CO₂ profile, while NCREs contribute significantly to CH₄ and N₂O. Despite the expansion of installed capacity, a gap persists with effective capacity, reflecting the structural vulnerabilities of Ecuador’s electricity generation system, including exposure to hydrological variability (Kraftnōt, referring in this research to electricity shortages caused by reduced hydropower generation under adverse hydrological conditions), insufficient thermal backup, a high concentration of hydropower plants, fluctuating fossil fuel subsidies, and limited diversification. This manuscript provides a technical and quantitative basis using annual CO₂, CH₄, and N₂O values and their CO₂ equivalents to inform future decarbonization scenarios that strengthen NCRE integration within international climate commitments and a sustainable electricity transition. Full article

Pectin, a natural biopolymer, is a cost-effective, biocompatible, non-toxic, abundant, and flexible material, making it suitable for recording high-quality bioelectric signals from the dynamic surface of the human body. In this work, pectin-based flexible bioelectrodes were developed for the non-invasive monitoring of biopotentials. The bioelectrodes are composed of pectin, polyaniline emeraldine salt (PANI-ES), glycerol, and polydimethylsiloxane (PDMS) and therefore abbreviated as PPGP. The PPGP electrodes demonstrated a bulk electrical conductivity of (7.54 ± 0.81) × 10⁻³ S/cm, a very low impedance of 34 Ω, and a high charge storage capacity of 4.63 ± 2.70 mC/cm². The surface morphology of the PPGP electrode plays a crucial role in enhancing biopotential signal detection by improving adhesion to skin contours. PPGP electrodes have been successfully used for high-fidelity electromyographic (EMG) bioelectric signal measurements. The developed PPGP bioelectrodes have the potential to advance next-generation human–machine interface (HMI) technologies and wearable healthcare systems, including prosthetic control, rehabilitation monitoring, and assistive communication devices. Full article

Degraded industrial sites in arid and semi-arid regions often suffer from loose surface substrates, weak water-retention capacity, high wind-erosion risk, and poor early vegetation establishment. Combining photovoltaic (PV) deployment with ecological utilization may improve near-surface habitats by shading, reducing wind speed, and regulating soil heat and moisture. This study investigated an ash storage yard of a coal-fired power plant in Ordos, Inner Mongolia, China, by comparing soil temperature, soil moisture, and near-surface wind-speed responses under three representative fixed PV tilt angles of 36°, 43°, and 50°, together with the corresponding early plant-growth suitability. A multi-physics model coupling near-surface airflow, water-vapor transport, and porous-media hydrothermal migration was established. A Gaussian suitability function combined with AHP-CRITIC weighting was used to construct a model-based comprehensive growth index (CGI) from soil temperature and moisture, while short-term field monitoring was used to validate afternoon soil hydrothermal trends. Among the three scenarios, the 36° configuration produced the widest horizontal heat–moisture-affected zone and the highest CGI values for alfalfa and Elymus nutans, reaching 0.7741 and 0.6875, respectively. Relative to the outside reference area, the rear PV zone reduced the near-surface wind speed by 33–40% and increased the plant heights of alfalfa and Elymus nutans by 49.4% and 37.8%, respectively. A first-order PVsyst assessment showed that the 43° configuration achieved the highest specific energy yield of 1814 kWh kWp⁻¹ year⁻¹, whereas the annual grid-connected output at 36° was only 0.59% lower. These findings indicate that the 36° configuration may provide a favorable compromise between early vegetation establishment and photovoltaic electricity generation among the tested scenarios. By linking renewable-energy production with microenvironment regulation and early vegetation establishment, the proposed framework provides a decision basis for the multifunctional and sustainable reuse of degraded industrial land. Nevertheless, the results represent a site-specific, single-season assessment and should not be interpreted as a universal optimum. Full article

Copper and lead contamination in loess areas poses a potential threat to soil environmental quality and sustainable land use, while the low permeability, high clay content, and strong buffering capacity of loess often limit the efficiency of conventional electrokinetic (EK) remediation. This study developed an enhanced EK system integrating novel hydrogel (NH) electrodes, a poly(diallyldimethylammonium chloride)-modified activated carbon/carbon fibre (MAC/CF) permeable reactive barrier (PRB), and a vertical voltage for the remediation of Cu- and Pb-contaminated loess. The effects of vertical voltage (0, 10, 20, 30, and 40 V) on EK behaviour, contaminant migration, and removal performance were investigated. The results showed that the MAC/CF PRB improved electrical stability, enhanced electroosmotic transport, and regulated pH evolution by providing conductive pathways and reactive sites for OH⁻ capture and metal adsorption. Compared with the system without a PRB, the accumulated electroosmotic flow (EOF) increased from approximately 680 to 980 mL. The vertical voltage further promoted Cu²⁺ and Pb²⁺ redistribution into the PRB and enhanced the migration–adsorption coupling process. The optimal voltage of 30 V achieved the best remediation performance, with Cu and Pb removal efficiencies of 69–80% and 32–36%, respectively, within 72 h at initial concentrations of 500 mg kg⁻¹. Mechanistic analysis revealed that the vertical voltage transformed the MAC/CF barrier from a passive adsorption layer into an electrically activated migration–capture interface. The synergistic effects of ion transport regulation, OH⁻ buffering, conductive network construction, and heavy metal adsorption effectively suppressed precipitation-induced focusing and improved remediation efficiency. This study provides a promising strategy for enhancing EK remediation of low-permeability and structurally sensitive soils. Full article

Lithium–sulfur batteries have become one of the research focuses of scientists over the past decade due to their high theoretical specific capacity (approximately 1670 mAh/g), low cost, and environmental friendliness, and the abundant reserves of their raw materials. Nevertheless, they still suffer from inherent drawbacks including poor electrical conductivity of elemental sulfur, electrode volume expansion during charge–discharge cycles, the shuttle effect and lithium dendrite growth, which severely restrict their practical application and industrialization. To address the above issues, extensive research has been carried out to optimize cathode materials, separators and electrolytes. In particular, the shuttle effect occurring during cycling can be effectively mitigated via separator modification. This paper briefly introduces the design strategies for separators for lithium–sulfur batteries, and mainly summarizes separator-modification methods using carbon materials, graphene, carbon nanotubes, heteroatoms, polymers, metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). Finally, the future development trends of lithium–sulfur batteries are prospected. Full article