Search Results (29,879)

Thermal losses significantly impact the efficiency of photovoltaic modules, particularly under high-temperature and variable cloud cover conditions in tropical climates. This study presents a novel thermal clustering methodology for predicting thermal losses in Monocrystalline Passivated Emitter and Rear Cell (MonoPERC) solar modules. Seven machine learning algorithms were tested using two methods, a baseline approach and a thermal clustering approach, which allow better energy yield forecasting and a more comprehensive understanding of the behavior of PERC modules. The clustering methodology partitions data into distinct thermal regimes, enabling specialized model training for different temperature operating conditions. K-Nearest Neighbors (KNN) was the best model without clustering, achieving a 0.9612 correlation and a mean prediction error of 7.3 W. With the new thermal clustering method, Multi-Layer Perceptron (MLP) was the top performer, with a 0.9561 correlation and an NMAE of 0.1409. Ensemble methods, such as XGBoost and Random Forest, were also highly effective, while linear methods proved inadequate. Results demonstrate that K-Nearest Neighbors achieved superior baseline performance, while the thermal clustering approach improved prediction accuracy across all algorithms. The Multi-Layer Perceptron emerged as the best performer with the clustering methodology. Full article

The core of ocean thermal energy conversion (OTEC) is the transfer and conversion of heat energy, and the heat exchanger is a key component of the heat transfer between the surface warm seawater and the lower cold seawater. The working fluid has a significant impact on the efficiency of the entire cycle in the temperature difference cycle. This study aimed to improve heat exchange efficiency. The article studied heat exchangers, used R134a as the circulating medium, and applied ANSYS-FLUENT simulation software to analyze the variation in heat transfer coefficients. We obtained the trend in the heat transfer coefficient of the heat exchanger with the shape of an elliptical tube under the condition of ocean temperature difference cycles. Then we used a long short-term memory network and Adam optimization algorithm to establish the prediction model. The NSGA-II 11 algorithm was used to realize optimization objectives of the highest heat transfer efficiency and the smallest cross-sectional area of heat transfer tubes along the X and Y directions. Finally, the parameters of the evaporator and condenser ultimately resulted in three optimal solutions. The results of this study can provide a certain theoretical basis and reference value for the efficiency analysis, structure optimization, and experimental research of the subsequent ocean differential circulation heat transfer. Full article

Background and Objectives: Breast cancer is the most common cancer in women, with approximately 80% being oestrogen receptor positive, necessitating adjuvant endocrine therapy (AET) to reduce recurrence. Treatment adherence is crucial, yet 10–50% of patients take incorrect doses or discontinue therapy, which is associated with a 20% increase in mortality. AET may also impact bone health. This study aimed to explore patients’ beliefs about endocrine treatment, investigate how perceptions of medication risk and benefit affect adherence, and assess changes in bone mineral density (BMD) during therapy. Materials and Methods: A cross-sectional mixed-method study was conducted. One hundred patients diagnosed with oestrogen receptor-positive breast cancer in 2020 were sent the Beliefs about Medicines Questionnaire–Adjuvant Endocrine Therapy (BMQ-AET) and 101 semi-structured telephone interviews were completed. Initial and most recent Dual-Energy X-ray Absorptiometry (DEXA) scans were compared to assess changes in BMD. Results: The questionnaire response rate was 55% (n = 55). Forty-nine patients returned the postal paper survey and six patients responded via QR code. One hundred and one patients participated in semi-structured telephone interviews. Of the total cohort, 91.7% were adherent to AET, while 13 patients (8.3%) were non-adherent. Non-adherent patients had significantly lower BMQ-AET Necessity scores (mean 12.08 vs. 19.22; median 12 vs. 20; p < 0.001) and higher Concerns scores (mean 17 vs. 13.46; Median 17 vs. 13; p = 0.002). The most common reasons for non-adherence were joint pain and reduced quality of life (58%), highlighting a need for additional support in managing side effects. Among the participants with suitable DEXA data, the majority (54.2%) demonstrated an increase in BMD over time. Conclusions: This study demonstrates high adherence to AET, with non-adherent patients showing lower perceived necessity and greater concern about treatment. These findings emphasise the importance of addressing patient beliefs to enhance adherence. The observed improvements in BMD suggest that proactive bone health management, alongside AET, may mitigate expected declines, challenging conventional assumptions regarding therapy-related bone loss. Full article

In high-altitude highway tunnels, the efficiency of jet fans significantly impacts the performance and energy consumption of ventilation systems. To optimize jet fan efficiency under such conditions, this study combines outdoor model experiments with numerical simulations of physical models in longitudinal jet ventilation systems. A model was established using SpaceClaim (ANSYS 2022 R1), and numerical simulations were conducted using Fluent software (ANSYS 2022 R1) to obtain results. The effect of different mounting inclination angles (0° to 10°) on the performance of a jet fan was experimentally investigated, and a correlation formula for the lift pressure of the jet fan under different inclination angles was established. Comparative results demonstrate that the numerical simulations accurately capture the variation trend of fan lift pressure under different tilt angles observed in the experiments. Specifically, the lift pressure of the jet fan initially increases and then decreases with increasing tilt angle. Comparative analysis of pressure rise at installation angles of 0°, 2°, 3°, 4°, 5°, 6°, 8°, and 10° revealed that a peak pressure rise of 19.66 Pa was observed at 4° installation, demonstrating optimal performance at this angle. The velocity distribution indicates that tilt angles between 0° and 4° increase the airflow influence range, beyond which efficiency decreases due to kinetic energy loss at the base. The study determined that under these conditions, a jet fan installed at a 4° inclination angle exhibits optimal performance in high-altitude straight tunnels and is thus identified as the optimal installation angle. At this angle, both pressure-rise efficiency and airflow stability are effectively balanced; this configuration provides a critical design basis for energy-saving optimization in high-altitude tunnel ventilation systems. Full article

China’s ecological civilization construction and the “dual-carbon” strategy highlight the urgent need for coordinated governance of pollution and carbon reduction. Whether data elements and artificial intelligence integration (DEAII) can serve as a new pathway to achieve this goal remains to be explored. This study investigates the dynamic effects of DEAII on pollution and carbon reduction using panel data from 275 prefecture-level cities in China during 2009–2021. An evaluation index system and a modified coupled coordination degree model are developed to measure DEAII, while an ordinary least squares (OLS) fixed effects model is applied to assess its impacts. The results show stage-specific effects of DEAII, including the phenomenon of “pollution reduction but carbon increase”. Mechanism analysis indicates that improvements in green energy technology efficiency (GETE) and optimization of urban spatial structure are the main channels for achieving synergy. Heterogeneity analysis reveals that although government attention to environmental protection strengthens pollution control, it has limited effects on short-term carbon reduction. Moreover, the carbon reduction benefits of green energy transition pilots exhibit a time lag, and the “digital intelligence divide” generates negative spatial spillovers. These findings provide new evidence for the dilemma of “environmental protection without low-carbon benefits” and suggest policy directions for enhancing the coordinated governance of pollution and carbon reduction. Full article

Alongside technological innovations, the energy transition requires notable behavioral changes in the residential sector. Smart technologies (STs) can support this shift by promoting transparency, energy-conscious behavior, and automated efficiency gains; their adoption depends on user acceptance. This study investigates the determinants shaping adoption patterns of different STs in German households. Based on a standardized online survey of 284 participants within the SmartQuart project (2022 and 2023), the analysis examined the motivational, sociodemographic, and housing-related factors influencing usage. The investigation was guided by a conceptual framework adapted from the Unified Theory of Acceptance and Use of Technology 2. The results revealed that efficiency- and control-related motives mainly drive the adoption of energy-oriented technologies, such as energy monitoring and home energy management systems. In contrast, indoor air quality monitoring and smart home systems are primarily used to enhance residential comfort. Regression analyses demonstrated that education and building type have a significant impact on energy-oriented technologies, while income, age, and living space influence comfort-oriented applications. The findings highlight the importance of differentiated communication and user-centered technology design. Despite limited generalizability, this study offers relevant insights into the target group-specific adoption dynamics essential for promoting behavioral energy efficiency in the residential sector. Full article

Low Power Wide Area Network (LPWAN) has been established as the leading communication technology for the Internet of Things (IoT) era and the latest machine-to-machine (M2M) communication applications. Among various flavors of this communication paradigm, LoRa stands out as the most widely adopted one, due to its low power and long-distance characteristics. The motivation for this study arises from the growing demand for sustainable IoT connectivity in remote or off-grid environments, where gateways often operate under severe energy constraints. Ensuring their long-term functionality is essential, as gateway energy depletion can compromise the entire LoRa network’s operation and reliability. In this work, the contribution of a Gateway Energy-Oriented Time Division Multiple Access (GEOT) communication protocol to the longevity of the network is under scrutiny. In contrast to the majority of the established works that study the effects of the nodes’ energy consumption on the network lifespan, this work investigates the impact of gateway energy consumption and proposes a novel communication scheme tailored to the operational characteristics of gateways in LoRa systems, especially for deployments lacking access to the power grid. Following the same rationale, the proposed scheme is evaluated under various node-placement distributions to represent different application scenarios. Simulation results show that GEOT, when applied to gateways powered solely by renewable energy sources, extends the network lifetime by approximately 4.7 to 6 times compared to conventional solutions, depending on the spatial distribution of the nodes. Full article

Increased needs arising from efficient utilization of renewable energy sources and the emerging use of portable electronic devices have introduced new requirements and challenges, such as fast charging and discharging, high-speed energy delivery, longer lifetime, and recyclability. To meet these demands, the innovative use of supercapacitors is essential, as they can complement the batteries currently in use. One of the major disadvantages of supercapacitors is that their energy storage capacity (5–20 Wh/kg) is currently insufficient, compared to the capacity of batteries (~1000 Wh/kg). Supercapacitors have higher specific power (10 kW/kg) but lower specific energy density, which is another significant disadvantage compared to batteries. This has prompted researchers around the world to find innovative solutions to enhance the energy density of these materials. Carbon-based nanomaterials are one of the most widely used electrode materials for supercapacitors; therefore, the development of carbon-based nanomaterials plays crucial role in evolution of supercapacitors, due to their high electrical conductivity, large specific surface area, and excellent mechanical strength compared to conventional electrode materials graphite, copper, platinum, etc. Significant results have been reported in the scientific literature on novel carbon-based nanostructured materials such as carbon nanotubes, vertically aligned carbon nanotubes, graphene, activated carbon, or carbon nanoballs, which have a hierarchical pore structure, as well as hybrid systems combining these materials and the introduction of alternative electrolytes. This manuscript reviews briefly the background and fundamental characteristics of supercapacitors, classifying them. It also mentions the general electrochemical measurement methods used to evaluate the energy storage properties of supercapacitors, with emphasis on their specific characteristics and limitations. The integral components of supercapacitors, especially electrode materials, are considered to have considerable impact on the performance of supercapacitor devices (e.g., long life cycle, storage capacity, and high power density). Full article

The present study investigated the tensile behavior, failure mechanisms and deformation characteristics of glass fiber-reinforced polymer (GFRP) composites with symmetric [0°/90°/90°/0°] and asymmetric [0°/90°/0°/90°] stacking sequences across a temperature range of 30–150 °C. Tensile testing revealed superior mechanical performance in the symmetric lay-up, with higher tensile strength and failure strain sustained across elevated temperatures. Failure mode analysis revealed a transition from ductile failure to brittle failure with increasing temperature, which was more pronounced in the asymmetric lay-up, along with increased delamination and reduced fiber pull-out. Failure surface examination supported these findings, revealing better interfacial bonding and matrix integrity in the symmetric lay-up. Deformation analysis further confirmed a more homogeneous distribution of strain and longer failure time in symmetric laminates. Across all the metrics, including toughness, energy absorption, and strain uniformity, the symmetric configuration outperformed the asymmetric counterpart, underscoring the critical role of balanced stacking in enhancing the thermal durability. The observed temperature-induced degradation and its impact on mechanical and failure behavior emphasize the need for temperature-sensitive design strategies in GFRP-based structures. Full article

In Poland, the gradual reduction in hard coal mining represents a cornerstone of the energy transition and economic restructuring strategy, with all mines scheduled to close by 2049 under the Social Agreement. Given Poland’s strong reliance on coal, this process has far-reaching implications for energy security, employment, regional development, and macroeconomic stability. The aim of this study is to assess the role and scale of the hard coal mining sector’s contribution to GDP and to examine the consequences of its gradual decline for the national energy mix. In the input–output framework, a reduction in domestic hard coal supply is modelled as a shock to the output of the disaggregated hard coal sector, affecting both intermediate demand and value added through inter-industry linkages. The analysis applies an inter-industry input–output framework based on a decomposed Input–Output Table of Poland, where the aggregated “hard coal and lignite” branch was disaggregated into thermal hard coal, coking coal, and lignite. Reduction Variants (WR25%, WR50%, WR75%, and WR100%) were combined with Substitution Variant WS2, which assumes replacement of domestic hard coal with imported coal, natural gas, and electricity under varying price scenarios (−40% to +40% relative to reference levels). The Migration Variant was also included to account for labour market effects. This approach generated a set of 100 scenarios, reflecting possible pathways of Poland’s energy transition. The results demonstrate that in every scenario, reducing domestic hard coal supply leads to a decline in GDP. Losses range from −0.175% to −0.25% under WR25% scenarios to between −0.775% and −1.1% under WR100%, depending on the relative prices of imported substitutes. Substitution patterns are highly sensitive to price dynamics: under low natural gas prices, gas dominates the replacement mix (over 57% share), while under high gas prices, imported coal prevails (70–90%). Electricity imports consistently remain marginal. These outcomes highlight Poland’s structural dependence on coal, the vulnerability of GDP to external price shocks, and the limitations of substitution options. This study concludes that the reduction in domestic coal mining, though inevitable in the context of the EU climate policy, will not be economically neutral. It requires careful management of substitution pathways, diversification of the energy mix, and socio-economic support for coal regions. The input–output framework used in this research offers a robust tool for quantifying both direct and indirect effects of the coal phase-out, supporting evidence-based policy for a just and sustainable energy transition. Full article

This study investigates the ballistic performance and energy-absorption behavior of advanced multilayer ceramic composite armor systems composed of silicon carbide (SiC) ceramics, composite metal foam (CMF), rolled homogeneous armor (RHA), ultra-high-molecular-weight polyethylene (UHMWPE), aluminum, and rubber interlayers. The objective is to enhance impact resistance and optimize energy dissipation efficiency against armor-piercing (AP) projectiles. Ballistic tests were performed following the NIJ Standard 0101.06 Level IV specifications using .30” caliber AP M2 rounds with an impact velocity of 784–844 m/s. Experimental results revealed that the SiC front layer effectively fragmented the projectile and dispersed its kinetic energy, while the CMF and UHMWPE layers were the primary energy absorbers, dissipating approximately 70% of the total impact energy (≈3660 J). The aluminum and RHA layers provided additional reinforcement, and the rubber interlayer significantly reduced stress-wave propagation and suppressed crack growth in the ceramic. The most efficient configuration 0.5 mm RHA + 7 mm SiC + 7 mm EPDM + 7 mm CMF + 5 mm UHMWPE achieved an areal density absorption of 77.2 J·m²/kg and a unit thickness absorption of 190.6 J/mm. These findings establish a quantitative layer-wise energy dissipation framework, highlighting the synergistic interaction between brittle, porous, and ductile layers. This work provides practical design principles for developing lightweight, high-efficiency composite armor systems applicable to defense, aerospace, and personal protection fields. Moreover, this study not only validates the NIJ Standard 0101.06 ballistic performance experimentally but also establishes a reproducible methodology for quantitative, layer-wise energy analysis of hybrid ceramic-CMF-fiber armor systems, offering a scientific framework for future model calibration and optimization. Full article

The maritime sector, responsible for approximately 3% of global greenhouse gas (GHG) emissions, is under growing pressure to transition toward climate-neutral operations. Significant progress has been made in developing sustainable fuels and propulsion systems to meet these demands. Although electric propulsion and fuel cells are highlighted as key technologies for achieving net-zero carbon targets, they remain an immature solution for large-scale maritime use, particularly in long-distance shipping. Therefore, modifying internal combustion engines and employing alternative fuels emerge as more feasible transition strategies, especially in short-sea shipping and port applications such as tugboat operations. Among alternative fuels, hydrogen (H₂) and ammonia (NH₃) have emerged as the most prominent fuels in recent years due to their carbon-free nature and compatibility with existing marine compression ignition (CI) engines with only minor modifications. This study explores the viability of hydrogen and ammonia as alternative fuels for CI engines in terms of technological, economic, and environmental aspects. Also, using a life cycle assessment (LCA) framework, this study examines the environmental impacts and feasibility of gray, blue, and green hydrogen and ammonia production pathways. The analysis is conducted from both well-to-tank (WtT) and tank-to-wake (TtW) perspectives. The results demonstrate that green fuel production pathways significantly reduce emissions but lead to higher economic costs, while intermediate blends offer a balanced trade-off between environmental and financial performance. Moreover, the combustion stage analysis indicates that H₂ and NH₃ provide substantial environmental benefits by significantly reducing harmful emissions. Consequently, a Multi-Criteria Decision Making (MCDM) approach is employed to determine the optimal blending strategy, revealing that a 24% hydrogen and 76% marine diesel oil (MDO) energy share yields the most favorable outcome among the evaluated alternatives. Full article

Molybdenite and chalcopyrite closely coexist and have good natural floatability. During the Cu-Mo separation process, it is necessary to enhance the inhibition of chalcopyrite to reduce its influence on molybdenite. In this paper, a combined inhibitor, sodium thioglycollate (HSCH₂COONa) and sodium sulfide (Na₂S), with a molar ratio of 2:1, was obtained through pure mineral flotation experiments. It could reduce the impact on molybdenite while maintaining a good inhibitory effect on chalcopyrite. In the artificial mixed minerals test, the use of the combined inhibitor (80 mg/L) can achieve good indicators with Mo grade and recovery rate of 54.34% and 88.12%, respectively, and Cu grade of 2.15%. The contact angle test shows that the combined inhibitor can significantly reduce the wettability of the chalcopyrite surface while having a relatively small effect on molybdenite. The infrared spectroscopy and SEM-EDS energy spectrum indicated that the combined inhibitor C = O and S-H groups underwent chemical reactions on the surface of chalcopyrite and squeezed out kerosene on the surface of chalcopyrite. Molecular dynamics simulations indicate that the HS⁻, S²⁻, and HSCH₂COO⁻ components in the combined inhibitor are more likely to act on the surface of chalcopyrite, exerting an enhanced inhibitory effect on chalcopyrite. Full article

The multi-microgrid integrated energy system (MM-IES) plays a vital role in enhancing energy utilization efficiency and promoting the coordinated consumption of renewable energy. However, the realization of low-carbon dispatch in MM-IES is hindered by multi-energy coupling and the need for distributed coordination under increasingly stringent carbon emission constraints. To address these issues, a distributed scheduling strategy that integrates demand response and green certificate trading mechanisms is proposed. Firstly, a low-carbon integrated energy microgrid (IEM) model integrating carbon capture and storage (CCS) and power-to-gas (P2G) technologies is proposed to improve the system’s low-carbon regulation capability and mitigate the impact of multi-energy coupling in MM-IES. This integration enhances the system’s low-carbon regulation capability. Secondly, to incentivize user participation in system optimization, a demand response mechanism and a tiered green certificate trading model are introduced. On this basis, an MM-IES low-carbon economic dispatch model is established with the goal of minimizing total operating costs, carbon trading costs, and green certificate trading costs. To further protect the privacy of each microgrid and achieve efficient coordination, distributed algorithms are used to solve the model. This method only requires exchanging boundary information to achieve collaborative optimization between microgrids. Finally, the simulation results indicate that the proposed strategy can effectively reduce system operating costs and carbon emissions. Furthermore, the effectiveness of demand response and green certificate trading in promoting low-carbon economic operation of multi microgrid systems is verified. Full article

This study evaluates low-strength concrete incorporating recycled rubber aggregates from waste tires and polymer fiber for use as “forgiving” safety barriers that enhance road safety while promoting environmental sustainability. Incorporating the rubber and fiber enables recycling the tires close to the source where they were originally used—the road. These barriers are designed to absorb collision energy, reduce vehicle deceleration, and minimize the severity of accidents. The key requirements for such concrete are low strength, low elastic modulus, high ductility, high toughness, and minimal dispersion of large fragments upon failure. The study investigated various concretes containing different percentages of recycled rubber (0–20% by volume) and polymer fibers (0–1.2% by volume). We conducted compression, flexural, and dynamic impact tests to assess the effects of these additions on the properties of the concrete. Dynamic tests were carried out in a cantilever loading scheme with strain rates of 2.5–3 s⁻¹, to emulate barrier loading during car crush. Key findings include indications that recycled rubber decreases concrete strength, while its contribution to energy absorption is limited. In contrast, polymer fibers enhance the concrete’s elongation and toughness, increasing energy absorption. The quantity of fibers present in the fracture area is critical for energy absorption. Notably, energy absorption under dynamic loads is more significant than that under quasi-static loads; however, the difference between these results diminishes as the fiber percentage increases. Furthermore, quasi-static tests on fiber-reinforced concrete can effectively evaluate its response to impact loads. In conclusion, the combined use of recycled rubber and polymer fibers in low-strength concrete offers a sustainable solution for developing safer and more environmentally responsible roadside infrastructure by repurposing waste materials and reducing the ecological footprint of construction. Careful attention should be paid to the distribution of fibers within the concrete, as this significantly influences energy absorption. Full article