Search Results (1,818)

A self-powered graphene-enhanced hydrogel sensor (SGHS) with high contact-pressure sensitivity and mechanical robustness was developed for precise dynamic biomechanical and material contact sensing. The device generates transient electrical signals via contact electrification and electrostatic induction during contact–separation events, eliminating the need for any external power supply. The optimized SGHS achieves a maximum peak power density of 0.23 mW·m⁻², with contact-pressure sensitivities of 0.6 kPa⁻¹ and 0.26 kPa⁻¹ in the pressure ranges of 0.25–5 kPa and 5–25 kPa, respectively, which is competitive with or exceeds that of other externally powered and self-powered flexible dynamic stress sensors in the low-pressure range. Comprehensive analyses reveal that the pressure response originates from the enhanced piezodielectric effect in the graphene hydrogel layer under compression. The SGHS exhibits excellent mechanical durability, maintaining stable output after 10,000 loading–unloading cycles. Moreover, the pulse intensity, width, and waveform of its self-generated output provide distinctive features for identifying the type and surface characteristics of contacting objects. These results highlight SGHS as a promising candidate for next-generation intelligent, self-powered, and flexible dynamic sensing systems. Full article

There are some methods based on the railway power conditioner (RPC) that can address the imbalance issue, improve load fluctuation, and manage the regenerative braking energy (RBE) of the traction power supply system in high-speed railways. However, the coupling of imbalance compensation and energy storage is a problem in the RPC method. Therefore, a novel decoupling control method is proposed in this paper. The topology of the method is based on a three-phase converter, and the energy storage unit is connected to the DC side of the converter. A decoupling possibility and principle analysis is carried out. The mechanism of the proposed method in coping with different working conditions of high-speed railways is introduced in detail. Then, a capacity analysis and the control method are presented. According to the theoretical analysis, while the traditional RPC requires no extra capacity under single-task operations, its required capacity increases by 15.47% under typical hybrid conditions and can even surge by over 30% under severe coupling scenarios, to achieve the same effect as the proposed decoupled method. Finally, simulations and experiments are carried out to verify the effectiveness and flexibility of the novel method. Full article

Terminal valve closures are the main causes of hydraulic transient pressure in long-distance gravitational water supply pipelines. Therefore, reducing the hydraulic transient pressure in water supply systems through appropriate valve closure strategies is crucial. In this study, a mathematical model for the hydraulic transients contained in gravitational water supply pipelines was established using the method of characteristics for transient flows. On the basis of an actual project, MATLAB 2025b programming was used to calculate the effects of different valve closure strategies on the hydraulic transient pressure in a water supply system under various flow rate operating conditions. The results showed that the appropriate valve closure strategy should be determined according to the high-flow-rate operating conditions of the water supply system. Although extending the valve closure time can significantly reduce the fluctuations exhibited by the hydraulic transient pressure, an excessively long closure time may compromise the control efficiency of the water supply system. Compared with the linear valve closure strategy, the two-stage valve closure strategy produces smaller changes in the hydraulic transient pressure, thus reducing the hydraulic transient pressure fluctuations caused by valve closures to a certain extent. The two-stage valve closure strategy decreases the valve closure time and therefore improves the safety and flexibility of pipeline operations. This study provides a reference for determining the optimal valve closure strategy for terminal valves in similar water supply projects. Full article

Integrating renewable energy systems (RES) and hybrid energy storage systems (HESS) into railway traction power supply systems represents a critical pathway toward low-carbon and sustainable railway transportation as it enables the utilization of clean energy and enhances energy efficiency. However, this integration introduces new harmonic resonance challenges that require systematic analysis. To quantitatively analyze these harmonic resonance issues, this paper studies a flexible cooperative traction power supply system (FCTPSS) integrated with RES and HESS. Based on harmonic transmission theory, mathematical models of harmonic transmission for both the traction power supply system (TPSS) and the FCTPSS are established. Simulation models of the TPSS and FCTPSS are developed in MATLAB2021b/Simulink. Using these simulation models, the harmonic transmission characteristics of the TPSS and FCTPSS are compared and analyzed. The results indicate that the position of the locomotive and the access position of RES and HESS influence the harmonic transmission characteristics. Importantly, integrating RES and HESS shifts the resonant frequency to higher orders and effectively alleviates resonance issues, thereby improving power quality and supporting the reliable operation of sustainable railway systems. These findings offer valuable design guidance for incorporating RES and HESS into traction power supply systems to facilitate the transition toward greener and more sustainable rail transportation. Full article

Background: Although digitalization is recognized to improve the food supply chain, its effect pathways have not been thoroughly researched, especially in the context of developing countries. This study examines the association of three digitalization practices: digital internal practice (DIP), digital integration with suppliers (DIS), and digital integration with customers (DIC) with nine supply chain performance metrics: efficiency, flexibility, food safety/quality, reliability, traceability, food loss, and sustainability, mediated by operational efficiency, trust, and transparency, using food processing company case in Ethiopia. Methods: Using an explanatory approach, data from 153 respondents were analyzed through mediation-based structural equation modeling (SEM) in JASP (v.0.95.4.0). The analysis involved 27 direct and 81 indirect effect paths. Results: The results demonstrated a fundamental comprehension that while digital practices manifest direct positive (improvement) effects, a purely direct-impact assessment is insufficient. Statistically, more than half of the suggested direct paths were not significant. The total effects, on the other hand, were significant for all 27 paths tested with much stronger positive associations. Conclusions: The mediation-based examination of the relationship of digitalization practices on food supply chain performance offers essential insight, indicating that the impact of digitalization on supply chain performance is primarily indirect, functioning through the enhanced capabilities it fosters. Full article

This study focuses on the commonalities and differences in the public housing systems of three East Asian countries, using Japan’s UR Rental Housing as a case study. It employs a composite methodology that integrates architectural typology and cross-cultural comparison, constructing theoretical linkages within a three-dimensional framework of “social institutions–cultural context–spatial structure”. The research emphasizes three key dimensions: (1) The evolution of policy frameworks and their underlying socio-cultural drivers; (2) The spatial layout logic and functional concepts embedded in residential unit planning; (3) The transformation and inheritance of traditional residential values in contemporary housing design. The study strictly adheres to a progressive logic of “sample construction–type decoding–paradigm extraction–cross-domain comparison–theoretical feedback”. It begins by analyzing the core issues in the supply structure and spatial adaptability of affordable housing in China and South Korea. Next, it systematically examines the policy evolution and spatial design paradigms of Japan’s UR Rental Housing. Subsequently, it constructs a comparative analytical matrix for public housing in China, Japan, and South Korea, identifying transferable common experiences and pathways requiring localized adaptation. Finally, it proposes targeted recommendations across three dimensions, namely policy framework, spatial design, and community building: (1) At the policy level, a full lifecycle governance framework is advocated; (2) In spatial design, the principles of “compactness and efficiency” are emphasized, alongside enhanced flexibility and cultural relevance; (3) In community building, efforts are directed toward activating interpersonal connections and strengthening the social functional attributes of housing. This study emphasizes transnational comparability and knowledge transferability, aiming to provide practical insights for China’s affordable housing reforms and South Korea’s public housing modernization. It seeks to promote cross-national learning and collaborative innovation in the regional housing sector, offering both theoretical reference and practical pathways to realize the shared vision of “restoring housing to a human scale”. Full article

As the global imperative for climate neutrality intensifies, hydrogen (H₂) from fossil fuels remains central to decarbonizing hard-to-abate sectors. Conventional production via steam methane reforming (SMR), however, is carbon-intensive and, even with carbon capture and storage (CCS), incurs energy penalties and long-term storage constraints. This review develops a harmonized well-to-gate, market-oriented framework to evaluate methane pyrolysis (MP) relative to SMR and autothermal reforming (ATR), with or without CCS, moving beyond reactor-focused assessments toward system-level commercialization analysis. MP decomposes methane into hydrogen and solid carbon, avoiding direct CO₂ formation and the need for CCS infrastructure. Integrating with the reverse water–gas shift (RWGS) reaction enables flexible syngas production with adjustable H₂:CO ratios for methanol and chemical synthesis. A central finding is the dominant role of the “carbon lever”: MP generates approximately 3 kg of solid carbon per kg of H₂, making the carbon market’s absorptive capacity the primary scalability constraint. While carbon monetization can reduce levelized hydrogen costs, large-scale deployment would rapidly saturate existing carbon black and specialty carbon markets. Techno-economic evidence indicates that carbon prices above $500/ton are required to achieve parity with gray hydrogen, whereas $150–200/ton enables competitiveness with blue hydrogen. Lifecycle assessments further show that climate superiority over SMR or ATR with CCS requires upstream methane leakage below 0.5% and very low-carbon electricity. Commercial readiness varies, with plasma MP at TRL 8–9 and thermal, catalytic, and molten-media pathways remaining at the pilot or demonstration stage. Parametric decision-space analysis under harmonized boundary assumptions shows that MP is not a universal substitute for reforming but a conditional pathway competitive only under aligned conditions of low-leakage gas supply, low-carbon electricity, credible carbon monetization, and supportive policy incentives. The review concludes with a roadmap that highlights standardized carbon certification, end-of-life accounting, and long-duration operational data as priorities for commercialization. Full article

Understanding how pollinators adjust their behavior to maximize reproductive success in resource-limited desert ecosystems is a fundamental ecological question. In this study, we investigated X. mongolicus using a combination of field behavioral observations, pollen identification, nutritional analysis, and morphometric measurements to systematically examine interannual variations in its flower visitation spectrum, foraging behavior, bee bread composition, and offspring body size. Our findings reveal a striking contrast: although this species exhibits polyphagy in flower visitation, it shows dietary specialization in larval nutrition—over 92% of the pollen in its bee bread originates from just two leguminous species, A. mongolicus and O. bicolor. Foraging duration increased with rising temperature and humidity, and bees adapted to strong winds by flying close to the ground. Compared with 2024, the bee bread in 2025 had lower fresh weight but higher crude protein content, and offspring body size was larger—likely due to more abundant spring rainfall in 2025, which improved the flowering performance of A. mongolicus. Collectively, these results indicate that this bee species copes with resource uncertainty in desert habitats through flexible foraging range and highly specialized food storage, with its reproductive success closely tied to the nutritional supply of key plants and precipitation patterns. This study highlights the role of precipitation timing in shaping the nutritional foundation of plant–pollinator interactions, providing a scientific basis for the conservation and management of desert pollinators. Full article

Background: Global supply chains operate in increasingly volatile and technology-intensive environments shaped by digital transformation and artificial intelligence integration. While prior research has emphasized structural and technological enablers of flexibility, the behavioral foundations of supply chain adaptability remain insufficiently explored. Methods: This study develops a conceptual integration of the Kano model and the Cobb–Douglas production function to position managerial attitude as a strategic “delighter” within supply chain systems. The proposed framework models supply chain flexibility as a function of capital, labor, artificial intelligence integration, and managerial attitude within an extended economic representation. Results: The model suggests that managerial attitude acts as a behavioral amplifier that strengthens the performance effects of technological and economic inputs, potentially generating nonlinear gains in responsiveness and adaptive capacity. By distinguishing human-driven, algorithmic, and hybrid attitudinal configurations, the framework clarifies how behavioral orientations influence artificial intelligence adoption and supply chain flexibility, particularly in small and medium-sized enterprise contexts. Conclusions: Although conceptual in nature, the framework provides a formal analytical foundation for future empirical testing and elasticity-based sensitivity analysis in supply chain research. Full article

Distributed integrated energy systems embedding biomass combined heat and power (BCHP) have the potential to enhance energy supply reliability in rural areas and to support the low-carbon transformation. However, the sources and transmission paths of car-bon emissions remain difficult to quantify due to the multi-energy coupling and diverse conversion processes. To address these issues, this study develops a carbon flow tracking and scheduling strategy for BCHP-integrated distributed energy systems. First, a bio-chemical reaction process model for BCHP is established to enable a life cycle-based carbon emission accounting. Second, the flexible heat-to-power ratio characteristics of BCHP are considered to more accurately reflect multi-energy coupling under varying operating conditions. Third, a dual-objective optimal scheduling model is constructed by combining node carbon potential with operating costs, enabling the system to simultaneously minimize operating costs and carbon emissions. A case study of an integrated energy system in Anping County, Hebei Province, demonstrates that the proposed method reduces total carbon emissions by over 9.8%, increases renewable energy utilization by 15.2%, and lowers operating costs by 7.5%. The results reveal the carbon flow characteristics and emission reduction potential of rural distributed integrated energy systems embedding BCHP, providing methodological support and empirical evidence for refined low-carbon governance. Full article

Selectively modulating specific brain-rhythm bands with physical stimuli helps both to reveal neural mechanisms and to provide non-pharmacological treatment avenues for brain disorders. This study proposes and implements a multi-channel transcranial magneto-acoustic stimulation driving system based on amplitude-modulated (AM) sine waves (AM-TMAS) intended to supply a reliable hardware platform for noninvasive, focal low-frequency rhythmic electrical stimulation of deep-brain structures. The driving system implements a 64-channel AM module based on an FPGA plus high-speed DACs. Multi-channel precision is achieved via a unified high-speed clock and a global UPDATE trigger. To overcome the large separation between envelope and carrier frequencies, we developed a high-fidelity AM waveform generation method based on DDS + LUT + envelope multiplication. The algorithm first centers the carrier samples to preserve waveform symmetry, then applies LUT-based envelope coefficients and fixed-point envelope multiplication, enabling high-precision AM outputs with carrier frequencies from 100 kHz to 2 MHz and envelope frequencies from 0.1 Hz to 100 kHz. We tested the system’s rhythmic multi-channel AM output performance across frequencies and also measured magneto-acoustic-coupled rhythmic electrical signals produced by the AM-TMAS driving setup. Any single channel reliably produced high-fidelity AM waveforms with a 500 kHz carrier and 8 Hz/40 Hz envelopes; the measured carrier was 499.998 kHz with excellent frequency stability. Both envelope and carrier frequencies are flexibly tunable. At the nominal 500 kHz carrier, envelope fidelity was further quantified: the extracted envelopes achieved NRMSEs of 1.0795% (8 Hz) and 1.9212% (40 Hz), confirming high-fidelity AM synthesis. Under a 0.3 T static magnetic field, the AM-TMAS driving system generated rhythmic electrical responses in physiological saline that carried the expected 40 Hz envelope. The proposed AM-TMAS driver achieves high accuracy in AM waveform generation and robust multi-channel performance, and—when combined with an external static magnetic field—can produce rhythmically modulated magneto-acoustic electrical stimulation. This platform provides a practical technical tool for brain-function research and the development of rhythm-targeted neuromodulation therapies. Full article

Remote off-grid microgrids are often locked into diesel-backed operation because renewable variability creates multi-day and seasonal energy gaps that short-duration batteries cannot economically bridge. This work examines how renewable hydrogen can complement batteries and dispatchable biomass to push an existing hybrid microgrid toward near-autonomous, low-carbon operation, while remaining robust under future electrification demands. The analysis is based on real operational load insights from a remote off-grid system, combined with techno-economic optimization in HOMER Pro. The examined architecture includes PV panels, battery energy storage, a biomass CHP unit, and a diesel generator as backup; the hydrogen pathway additionally incorporates an electrolysis, storage and a PEMFC. Three scenarios are considered: a baseline PV/BAT configuration, an intermediate PV/BAT/BIO configuration that strengthens dispatchable renewable supply and short-term flexibility, and a PV/BAT/BIO/H₂ configuration targeting an increase in renewable energy penetration (REP). Results show that hydrogen integration shifts the system from curtailment-limited, diesel-supported operation to storage-enabled operation: surplus renewable production that would otherwise be curtailed is converted into hydrogen and later dispatched during prolonged deficits, enabling deep diesel displacement without compromising reliability. Hydrogen-enabled configurations achieve 90–99% REP, reduced diesel consumption, and lower CO₂ emissions, primarily by converting curtailed surplus into storable hydrogen. A rule-based EMS highlights technology complementarity across timescales, with batteries providing diurnal balancing and hydrogen covering longer deficits, which also reduces battery cycling stress. Overall, the study clarifies key design trade-offs, especially the need for coordinated PV expansion and storage sizing, and illustrates how a multi-storage portfolio can support high renewable penetration in such systems. Full article

(1) Background: Colombia hosts one of the world’s largest mixed-displacement crises, combining longstanding internal displacement with the influx of Venezuelan migrants. This case study examines how the Emergency Medical Team (EMT) Hospital Barco San Raffaele (HBSR) adapted its service-delivery model to respond simultaneously to internal displacement in the Colombian Pacific region and the Venezuelan refugee influx. Using the WHO EMT Surge Capacity Framework, the study analyses how health services were adapted across two concurrent displacement contexts. (2) Methods: A mixed-methods comparative case study was conducted using mission reports, epidemiological surveillance data, policy reports and institutional documents collected between November 2020 and May 2021. Data were analyzed through a thematic analysis structured around the four domains of the WHO EMT Surge Capacity Framework (Staff, Structure, Supplies and Systems), to examine how service adaptation was operationalized across different geographic, sociocultural and legal environments; (3) Results: EMT HBSR adapted staffing composition, supply chains, infrastructure, and operational systems across both settings. Its hybrid model, combining a hospital boat platform with mobile outreach teams, enabled continuity of primary care, mental, maternal and child health, and community-based services in geographically isolated and culturally diverse communities; (4) Conclusions: The findings illustrate how flexible EMT operational models can support the adaptation of health services, and reduce health access inequalities in displacement contexts characterized by high mobility, confinement and limited health system capacity. Mobile platforms, such as hospital boats, appear to be a viable strategy for ensuring continuity of care along migratory routes and in geographically isolated areas affected by protracted instability. Full article

High renewable energy penetration creates significant operational challenges for power systems, especially during extreme weather that disrupts supply–demand balance. This study introduces a framework that integrates extreme scenario identification, data augmentation, and power balance optimization. It defines extreme wind speed events, such as sudden drops, surges, and persistent anomalies, and uses a sliding-window algorithm to extract these events from historical meteorological data. To address the scarcity of extreme samples, a new data augmentation method combines the Wasserstein Generative Adversarial Network with Gradient Penalty (WGAN-GP) and iterative distribution shifting. This approach focuses the generated data on distribution tails while preserving diversity and temporal consistency. An optimization model, which includes various generation resources, energy storage, and load shedding, is developed to assess system flexibility under extreme conditions. Case studies on the projected 2030 Northeast China Power Grid show that the augmentation method expands extreme scenario datasets from 150 to 1000 samples, maintains extremity and temporal consistency, and reveals that wind curtailment rises sharply above 70% renewable share, with storage systems providing key flexibility in high-output scenarios. Full article

The growing electrification of ports and maritime transport requires flexible power systems capable of supplying multiple voltage levels with high efficiency and power quality. Battery-based power barges offer a promising solution, but their power conversion systems must handle wide voltage and power ranges while remaining stable under dynamic operating conditions. This paper presents a scalable multi-stage power conversion architecture for battery-based power barges that can supply both low-voltage and high-voltage AC loads from a common DC source. The system combines isolated Dual Active Bridge (DAB) DC–DC converters with a three-level Neutral-Point-Clamped (NPC) inverter. An input-parallel output-series DAB configuration is used for high-voltage operation, enabling modularity and scalability within semiconductor limits. A coordinated control strategy ensures stable DC-link regulation, balanced module operation, and high-quality AC voltage generation. Simulation results confirm stable operation, fast dynamic response, a voltage THD below 4%, and overall efficiency above 95%, demonstrating the suitability of the proposed architecture for future power barge and port electrification applications. Full article