Search Results (5,434)

Land-reuse planning after coal mining must distinguish restoration needs, evidential readiness and the ability to fund continuing obligations. This study examines that distinction through 69 Chinese mine-area units, six purposively selected coal-related electricity statements and one monthly monitoring report for 13 plants within a single base. Recalculation of the inventory reveals 22 distinct substantive score profiles. Separating data completeness from physical restoration difficulty changes the screening category of 7 units; a 20% perturbation of one indicator weight changes up to 10 categories. Thus, complete scoring does not imply stable prioritization. We connect this screening diagnosis to non-compensatory land-use prerequisites and a task-based restoration-funding condition. Capacity-denominator reconciliation changes normalized electricity output by 0.06–15.01% in the monitored dataset. In the Huainan demonstration, floating photovoltaics and aquatic recovery remain unresolved but require different investigations. A discounted funding extension shows how degradation and additional dated obligations can remove an apparent maintenance surplus. The contribution is an auditable separation of investigation priority, alternative-specific eligibility and financial coverage under incomplete evidence. The findings support conditional documentary planning rather than national rankings, validated project profitability or observed ecological recovery. Full article

Centrifugal pumps are commonly utilized to transfer liquids from one point to another in water supplies, irrigation systems, industrial processes, power generation, and HVAC applications. The issue of energy saving in pump operations is still a hot topic for researchers to both reduce energy costs and help preserve energy sources, because centrifugal pumps hold special importance for a sustainable energy future. The majority of these hydraulic machines are operated at a constant speed through throttle valves; however, variable speed technology offers a wide range of operation speeds using variable speed drives (VSDs). This study aims to lessen and mitigate the electricity costs of the operation of pumps by saving energy through variable speed control. The control method of variable speed for centrifugal pumps is mainly separated into two categories: constant pressure pump control (CPPC) and proportional pump control (PPC). In this paper, a horizontal multistage centrifugal pump operated with three different control methods, including throttling control at a fixed speed for full loads and part loads, variable speed control at a constant pump pressure, and variable speed control in proportional control mode, is investigated. All of the numerical values of flow rates, pump heads, electrical input power, and other variables are experimentally measured. The system curve of the used pump and pump characteristic curves are created based on the results of the experiments for applied control methods. Each control method applied on the test rig is assessed in terms of energy consumption to decide if the control technique is economically feasible. Payback periods are calculated through pump control methods within the scope of economic sustainability. This research demonstrates that the payback periods of the VSD are 7.4 and 12.6 months for proportional control modes and 45.18 months for constant pressure pump control. Applied variable speed methods achieve significant energy savings compared to throttling control for sustainable energy consumption that aligns with the Sustainable Development Goals (SDGs) of the United Nations (UN). This article demonstrates how flow regulation techniques in pumping systems contribute to sustainable energy consumption and reduce carbon footprint. Full article

Heat pumps are increasingly used for low-temperature heating applications. But their operation can create electricity demand peaks during periods of high thermal load. This paper presents a concept and calculation study for integrating phase change materials (PCMs) with air-to-water heat pump (AWHP) systems as a condenser-side thermal buffer for residential buildings. The analyzed retrofit-oriented storage unit is a 200 L tank containing 30% PCM by volume, corresponding to 60 L of paraffin PCM and 140 L of water. The sizing calculation gives 3.08 kWh of PCM thermal storage, 0.81 kWh of sensible storage in the remaining water over the 55–60 °C interval, and almost 3.89 kWh of total short-term thermal reserve for the PCM-plus-water tank. A 200 L water tank over the same 5 °C interval would store approximately 1.16 kWh. At the nominal 14 kW heat pump output, the PCM buffer corresponds to about 13.2 min of operation. At representative part load it corresponds to about 53 min at 25% load and 26 min at 50% load. The PCM sizing model predicts storage capacity, buffer time and possible cycling relevance, but it does not by itself predict a seasonal COP increase. Therefore, annual electricity and economic effects are evaluated only as COP-uplift sensitivity cases, including 0%, 3%, 4%, 5%, 8%, 15% and 28.6%. Given the assumptions in this study, the PCM add-on reaches positive net present value at approximately 11% COP uplift when the initial marginal investment and discounted year 10 replacement cost are considered. Approximately 14.1% is reached if the replacement cost is added upfront as a simplified lifecycle basis. The results indicate that the condenser-side PCM buffer may be technically useful for short-term thermal buffering and possible on-off cycle reduction, but its annual energy and economic benefit requires dynamic simulation or experimental validation. Moreover, peak-demand reduction, demand shifting and renewable electricity utilization are discussed as potential applications of the buffer concept. Full article

An important consideration in fast-hole drilling electrical discharge machining (FHD-EDM) systems is the reliable power delivery under high current and high temperature operating conditions. The developed mathematical model considers the electrical conductivity, the temperature-dependent electrical resistivity, the contact resistance, the Joule heating, the convection, the radiation and the transient heat transfer to analyze the coupled electrical and thermal behavior of the system. The model predicts voltage drop, current density, electrical resistance, power loss, temperature rise, heat flux and thermal hotspot development under various operating conditions. The results show that increasing current and contact resistance lead to higher electrical losses and maximum temperature, while improved cooling decreases both electrical losses and maximum temperature. These results emphasize the influence of electrical loading, contact resistance and cooling conditions on the electro-thermal response of the FHD-EDM power distribution unit. Low contact resistance, moderate conductor thickness and improved cooling was determined as design conditions based on Taguchi analysis. A surrogate-assisted multi-objective optimisation framework based on Gaussian Process Regression (GPR) and the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) is also employed to investigate the trade-offs between maximum temperature, power loss, and voltage drop. The proposed framework provides a systematic approach for analysing the coupled electro-thermal behaviour of the PDU and evaluating design trade-offs within the investigated operating conditions. In conclusion, the proposed scheme can be considered as an efficient solution for optimizing the PDU efficiency, thermal stability, operational reliability, and component lifespan, for high power EDM systems. Full article

Existing and prospective maritime carbon-pricing regimes, together with uncertain renewable generation, complicate the low-carbon operation of shipboard integrated energy systems (SIES), particularly when network voltages and coupled electrical, heating, and cooling demands must be coordinated. To address this problem, this paper develops a two-stage robust optimization framework for day-ahead unit commitment and dispatch of diesel generators, renewable energy sources, energy storage, alternative maritime power, and carbon capture systems. A shipboard-adapted second-order cone programming (SOCP) DistFlow formulation combines an impedance-ratio-dependent operational security margin with node-specific voltage envelopes. The resulting min–max–min problem is solved by column-and-constraint generation with Big-M linearization. Case studies on a 20-bus shipboard microgrid demonstrate that the framework maintains nodal-voltage feasibility under the modeled worst-case deviations and provides a favorable robustness–cost trade-off. In out-of-sample tests, no infeasible robust realization is observed among the sampled scenarios, whereas the deterministic schedule exhibits infeasibility. Under the assumed capture efficiency, carbon capture also substantially reduces net emissions relative to the no-capture case. The proposed framework supports network-feasible, low-carbon day-ahead scheduling under renewable-generation and multi-energy-load uncertainty without altering the voyage plan. Full article

The transition to low-emission (LE) dairy production is essential for mitigating agricultural greenhouse gas (GHG) emissions. However, the interannual variability and principal drivers of farm-level GHG footprints across intensive dairy farms remain insufficiently characterized, constraining targeted mitigation strategies. This study aimed to (i) quantify interannual variation in on-farm GHG emission intensity, (ii) characterize management contrasts between high- and low-emission farms, (iii) clarify the underlying mechanisms, and (iv) identify optimization pathways. A supplementary sensitivity analysis encompassing upstream emissions associated with feed production was performed using an expanded system boundary to assess the effects of system boundary selection on the estimated GHG emissions. Using 3-year (2021–2023) field data from 22 intensive dairy farms, a standardized farm-level GHG inventory was used to quantify operational GHG emission intensity per unit of fat- and protein-corrected milk (FPCM). The production-weighted mean on-farm operational GHG intensity was 0.86 kg CO₂-eq kg⁻¹ FPCM, with enteric methane constituting the dominant emission source. Incorporating upstream emissions associated with feed production contributed an additional 0.427 kg CO₂-eq kg⁻¹ FPCM, yielding a total emission intensity of 1.287 kg CO₂-eq kg⁻¹ FPCM under the expanded system boundary, representing a 49.7% increase relative to the operational inventory. Feed upstream emissions accounted for 33.2% of the total emissions estimated within the expanded system boundary. Both herd size and energy consumption exhibited increasing trends throughout the study period, whereas the proportion of lactating cows relating to the total herd declined from 46.01% in 2021 to 44.32% in 2023, suggesting that the expansion of the overall herd exceeded the corresponding growth in the lactating cow population. Under the operational system boundary, high-emission (HE) farms exhibited relatively greater contributions to their GHG emission profiles from enteric methane production, electricity consumption, and manure management activities. Conversely, LE farms attained improved performance through higher proportions of lactating cows, greater feed efficiency, and manure anaerobic digestion. Correlation analysis linked herd size, energy consumption, and dry matter intake positively to on-farm GHG emissions. Dietary starch was associated with manure N₂O emissions, while feed efficiency was associated with higher energy-related GHG emissions. Overall, herd composition, feeding management practices, energy utilization, and manure management strategies were identified as principal determinants of on-farm GHG emission performance. Furthermore, the sensitivity analysis employing an expanded system boundary demonstrated that incorporating upstream emissions associated with feed production substantially elevates the overall GHG emission intensity expressed per kg FPCM. This study helps address the lack of multi-year farm-level evidence for China’s dairy sector and proposes integrated strategies—herd structure adjustment, precision feeding, clean energy exploitation, and manure management—alongside sustained long-term monitoring, given the pronounced interannual variability. These findings highlight the roles of farm-level GHG inventories in identifying targeted on-farm emission mitigation opportunities and expanded system boundary assessments in quantifying the overall GHG burden associated with the entire dairy production supply chain. Full article

Against the backdrop of the energy crisis and environmental pollution, semi-solid lithium-ion batteries have been widely applied in energy storage and electric vehicles. Accurate joint estimation of state of charge (SOC) and state of energy (SOE) is key for the safe and efficient operation of battery management systems (BMSs). To solve the problems of existing methods, such as open-loop error accumulation, strong dependence on mechanistic models, insufficient multi-scale temporal feature extraction and poor adaptability of traditional attention mechanisms, this paper proposes a hybrid deep network model named CNN-PMSTCN-BASE-GRU. The model uses a one-dimensional convolutional neural network (1D CNN) to extract preliminary features, and a Parallel Multi-Scale Temporal Convolutional Network (PMSTCN) to capture both short-term transient characteristics and long-term evolution rules of battery data. The Branch-Aware-Squeeze-and-Excitation (BASE) attention mechanism is introduced to realize adaptive weighting of multi-branch features, and dual-path gated recurrent unit (GRU) is adopted for collaborative SOC and SOE estimation. An unscented Kalman filter is further utilized to suppress noise and smooth the output. The experiment was conducted under different temperatures and driving cycle conditions. The results show that the proposed model reduces the average mean absolute error of SOC estimation by 30.32% compared to the baseline model under variable temperature conditions, providing an effective solution for accurate multi-state estimation of lithium-ion batteries. Cross-material validation was carried out based on the publicly available INR 18650-20R Battery dataset from the University of Maryland, and it demonstrated excellent cross-material performance. Full article

The vibration characteristics of bearings in the Electric Drive Unit (EDU) of electric vehicles have a direct impact on the overall Noise, Vibration, and Harshness (NVH) performance. Due to the high speed of the drive motor, the importance of reducing shaft system vibrations has grown. Wave Washer (WW) is used to apply axial preload to bearings, thereby mitigating shaft system instability. In this study, the EDU was modeled using the Multi-Body Dynamics (MBD) simulation software ADAMS, and the effect of WW preload on bearing vibration was analyzed. The simulation results revealed that the dominant low-order vibration peak around 400 Hz was reduced by up to 30 dB. Notably, the vibration reduction effect was evident as the preload increased to level A, whereas only marginal improvements were observed beyond this level, indicating a saturation tendency. To provide a physical interpretation of this behavior, a simplified analytical stiffness formulation based on Hertzian contact theory was employed. The results suggest that the observed saturation tendency is associated with both the stabilization of rolling-element contact conditions and the nonlinear relationship between preload and bearing stiffness. Full article

Manufacturing-induced gear deviations can generate ghost orders, but direct validation from measured geometry to assembled-drive end-of-line (EOL) vibration remains scarce. This study tests an EOL-blind, falsification-oriented workflow for an electric-vehicle reducer. Repeated coordinate-measuring-machine reports of one 24-tooth gear yielded tooth-indexed pitch deviations with a dominant tenth circumferential spatial harmonic (k = 10) on both flanks (spectral-energy cosine similarity 0.952–0.994). Before EOL amplitudes were inspected, k = 10 was frozen and mapped to a sideband-order offset of ΔO = 3.29125; adjacent k = 9 and 11 harmonics and ±0.25-order shifted families served as controls. Industrial testing included 8974 spectra from 8232 unique units. Across mesh harmonics p = 1–6, median symmetric prominence was 0.485, 0.750, and 1.341 dB for k = 9, 10, and 11, respectively. The p = 1–15 analysis suggested a k = 10 advantage over shifted controls, but the eight-bin shift coincided with the local-background boundary and cannot establish specificity. The k = 11 family remained stronger. Grouped holdout against a 31.625-order upper-tail endpoint yielded ROC AUC = 0.488. Independently measured geometry can define an a priori order family, but repeatable spatial harmonics are not necessarily unique or predictive assembled-drive noise, vibration, and harshness (NVH) markers. Full article

This article addresses research challenges related to improving switched reluctance motor (SRM) performance, particularly for applications in electric vehicle propulsion systems and starter-generator units. The primary objective of the study is to increase energy conversion efficiency by reducing winding losses. The efficiency improvement was achieved by developing a novel stator winding topology. Conventional SRMs typically employ a double-layer concentric winding. The authors proposed two original stator winding configurations that significantly increase the fill factor. These two variants were compared with the conventional winding arrangement. Based on numerical analyses, the influence of the proposed winding topologies on the static characteristics of the SRM, as well as its performance under constant-torque and constant-power operating conditions, was investigated. The numerical results were experimentally validated using a prototype SRM equipped with the proposed stator winding configuration. Laboratory measurements confirmed the precision of the numerical predictions. Full article

Public transport is central to urban decarbonization, yet its greenhouse-gas (GHG) performance varies with transport mode, propulsion technology, energy source, passenger utilization, route and terrain conditions, operating context, and accounting boundary. This systematic review synthesized worldwide quantitative evidence on GHG emissions attributable to public passenger transport. Scopus, Web of Science, and Transportation Research International Documentation (TRID) were searched through 9 September 2026. Primary quantitative studies reporting public-transport-specific GHG, CO₂, CO₂e, or carbon-footprint outcomes were eligible. Of 1616 records identified, 93 reports representing 92 underlying studies were included following PRISMA 2020 screening. Life-cycle assessment was the most common study design (42 studies), followed by direct measurement (33) and modeling/simulation (13). Buses dominated the evidence base (81 studies), and battery-electric or electricity-based pathways were examined in 45 studies. Sixty-nine reports provided a defensible principal quantitative value. Among 56 reports with an explicit comparator direction, 55 reported lower emissions for the evaluated public-transport option. Results were not pooled because functional units, system boundaries, technologies, energy pathways, and operating contexts differed substantially. Methodological confidence was high for 21 studies and moderate for 71. Overall, decarbonization performance was conditional on energy supply, utilization, infrastructure, and life-cycle assumptions, indicating that public-transport technologies should be evaluated as components of context-dependent transport-energy systems rather than as inherently low-carbon solutions. This review was not prospectively registered. Full article

Water lost from distribution networks has already consumed electricity, but the associated greenhouse gas burden is rarely quantified, because water balances and organizational emission inventories use different boundaries. This study links the two within the Greek managerial-adequacy framework for a purposive sample of eight utilities and 14 utility-year observations (2024–2025). Electricity supply points are classified by activity and the attribution is graded, which isolates water-supply electricity from organizational totals that other activities can dominate: in one island municipality, fugitive emissions from solid-waste disposal make up 94% of the declared total. Water-supply energy intensity ranges from 0.538 to 2.434 kWh/m³ and operational carbon intensity from 0.198 to 0.895 kg CO₂eq/m³ of system input. Under proportional average-intensity allocation, reported real losses carry 22.0–67.5% of each utility’s water-supply electricity emissions, or 2708 t CO₂eq in the 2025 cross-section. These are accounting allocations from top-down water balances, not measurements of leak-specific energy use. A conditional screening shows that leakage reduction overlaps European public-investment carbon values only under stated unit-cost assumptions, and that the carbon case weakens as the grid decarbonizes while the water and electricity savings do not. The results support activity-level electricity reporting and the joint consideration of leakage, energy intensity, and system scale when mitigation measures are prioritized. Full article

Integrating direct air capture (DAC) with building heating, ventilation, and air conditioning (HVAC) systems could use existing air handling infrastructure for CO₂ capture while reducing ventilation-related energy demand through increased recirculation. However, reported energy, climate, cost, and energy-saving outcomes are difficult to compare because studies use different system boundaries, heat supply assumptions, and baselines. This review systematically synthesizes 38 studies on HVAC-, air handling unit-, duct-, and ventilation-integrated DAC. A normalization framework separated electrical demand, thermal demand, heat delivery assumptions, cost boundaries, and energy-saving baselines. Across 15 studies in the harmonized energy comparison, the grid-drawn electricity equivalent ranged from 475 to 2774 kWh_e/tCO₂, strongly influenced by regeneration heat supply and system boundary choices. Break-even grid carbon intensities ranged from 360 to 2103 gCO₂/kWh, with 13 of 15 cases maintaining a positive operational gross-capture balance at an illustrative 400 gCO₂/kWh. These climate indicators were interpreted as carbon removal metrics only where the captured CO₂ was associated with sufficiently durable retention; for vented or otherwise non-durable pathways, they were treated as diagnostic operational balances rather than evidence of carbon removal. Six comparable gross levelized cost estimates were normalized to 173–382 USD₂₀₂₄/tCO₂, with a median of 240 USD₂₀₂₄/tCO₂. Reported building energy savings could not be pooled because 18 studies used seven baseline types, with at least one system shifting from energy saving to penalty across climates. The evidence remains predominantly modelled and unevenly reported, highlighting the need for boundary-explicit field measurements and consistent reporting. Full article

Intelligent hydrogel sensors are integrated sensing devices employing stimuli-responsive hydrogels as the core functional sensing layers. Featuring tissue-mimetic mechanical flexibility, superior biocompatibility, and dynamic stimulus responsiveness, they fundamentally resolve the mechanical and biological interfacial mismatch between traditional rigid electronics and soft living tissues, providing new avenues for in situ, real-time, and in vivo physiological monitoring and precise biomedical intervention. This review systematically elaborates the full-scale design logic, multifunctional integration strategies, and cutting-edge biomedical applications of engineered intelligent hydrogel sensors. The material selection principles covering natural, synthetic, and hybrid polymer systems, multi-mode crosslinking strategies for three-dimensional network construction, and functional modification approaches for conductivity, biological recognition, self-healing, adhesion, and antifouling performance are comprehensively summarized. The sensing mechanisms that convert physical deformation and biochemical variations into quantifiable electrical or optical signals are classified and analyzed, including resistive/capacitive, piezoelectric, electrochemical, and optical transduction modes. This review strictly focuses on hydrogel-dominant sensing platforms and discusses their versatile applications in wearable physiological monitoring, implantable in vivo sensing, and in vitro biochemical diagnosis. Particular emphasis is placed on the core role of intelligent hydrogels in constructing “perception–feedback–treatment” closed-loop theranostic systems, which enable autonomous on-demand drug release or physical stimulation in response to pathological signal changes, achieving integrated diagnosis and therapy. Despite substantial laboratory progress, the clinical translation of intelligent hydrogel sensors still faces critical challenges, including insufficient long-term in vivo stability, biological contamination, uncontrollable immune responses, large-scale manufacturing difficulties, and poor performance consistency. This review further outlines future development directions based on artificial intelligence-assisted material design, biomimetic structural engineering, advanced 3D/4D printing manufacturing, and interdisciplinary integration. It is anticipated that intelligent hydrogel sensors will evolve into highly integrated, personalized, and autonomous intelligent healthcare units, promoting the paradigm shift from passive universal treatment to proactive, personalized, and predictive precision medicine. Full article

Concentrated photovoltaic cooling and membrane distillation channel enhancement are commonly investigated as separate design problems, without considering the quality of the recovered heat available to the desalination unit. This study presents a thermally coupled CPV–DCMD system in which the cooling and desalination components are systematically co-designed. Validated numerical models were used to compare six internally finned microchannel heat sinks and eight baffled DCMD configurations with their respective blank channels. The recovered CPV heat was transferred to the saline feed through a heat exchanger while accounting for a 5% heat loss. The selected CPV configuration, comprising a 10 × 10 fin arrangement with a height of 60% of the channel, reduced the average and maximum cell temperatures at 1500 suns from over 101 and 112.4 °C to 63.8 and 70.56 °C, respectively, while increasing electrical efficiency from 37.5% to 39.2%. The selected DCMD design employed uniform height baffles in both channels, enhancing near-membrane mixing while limiting hydraulic losses. It increased permeate flux by 6% compared with the blank module and required 88% less hydraulic power than the uniform tall baffle configuration. Under the coupled operating conditions, increasing the coolant flow rate improved CPV cooling and electrical performance but reduced the recovered-heat temperature and DCMD productivity. Therefore, the coolant flow rate should be selected by balancing the allowable cell temperature with electrical efficiency and freshwater production. Full article