Search Results (110)

The growing demand for energy-efficient and sustainable manufacturing requires maintenance strategies that extend beyond reliability optimization toward active energy management. This study proposes a Smart Hybrid Maintenance System (SHMS) that integrates Reliability-Centered Maintenance (RCM) and Condition-Based Maintenance (CBM) principles with energy performance assessment. The framework combines classical reliability indicators (MTBF, MTTR, and Availability) with energy-oriented Key Performance Indicators (EEI, EENS, and OEE) to quantify the relationship between machine degradation, operational availability, and energy efficiency. The methodology was validated using two datasets: NASA N-CMAPSS for simulation-based benchmarking and the Smart RDM industrial environment for real process data. Results demonstrate that predictive maintenance supported by the Hybrid Risk Index ($HRI$) reduces unplanned downtime by up to 12%, corresponding to a 7–9% decrease in specific energy consumption and a measurable improvement in the Energy Efficiency Index. By embedding energy metrics into predictive maintenance decision-making, the SHMS enables dual optimization of reliability and energy performance. The proposed approach not only enhances equipment availability and cost efficiency but also supports industrial decarbonization targets, positioning predictive maintenance as a key enabler of energy-aware and sustainable manufacturing aligned with Industry 5.0 objectives. Full article

The rapid growth of Waste Electrical and Electronic Equipment (WEEE) in the European Union highlights the need for a rigorous understanding of its long-term dynamics and the role of innovation in shaping its trajectory. This study investigates how innovation influences the dynamics of WEEE generation in the European Union. We develop an innovation-adjusted mathematical model of e-waste as a stock flow system and prove the existence and global stability of a unique positive equilibrium. The model analytically generates an environmental Kuznets-type turning point and shows that innovation reduces waste accumulation by accelerating effective depreciation. To link the theoretical results with empirical patterns, we embed the model in a STIRPAT panel specification using annual data for 27 EU member states from 2013 to 2023, where EU Eco-innovation Index (EEI) serves as a composite index which directly captures policy-driven green technology and circular economy activities, aligning precisely with our theoretical framework. We also extend the quasi-demeaning transformation to panels with correlated shocks and establish its consistency under a factor structured error process. The empirical estimates confirm a positive effect of income on WEEE at lower development levels and a negative coefficient on its squared term, consistent with an inverted U pattern, while innovation is associated with lower waste intensity. These findings demonstrate how mathematical modeling can strengthen the interpretation of macro panel evidence on circularity and provide a basis for future optimization of innovation driven sustainability transitions. Full article

This study evaluates South Africa’s progress toward achieving SDG 4.5 by examining disparities in educational access and outcomes for vulnerable groups, including girls, children with disabilities, rural populations, and low-income households. The study recognises multidimensional inequalities and develops strategies that promote inclusive and equitable education. The quantitative approach was employed by constructing a composite Educational Equity Index (EEI) using seven indicators: gender parity in primary and lower secondary completion, location-based attainment among adults, gender parity in adult lower secondary education, disability parity in primary completion, gender parity among the poorest quintile, and wealth parity in youth literacy. These indicators were standardised and aggregated to develop the EEI. The study developed a multivariate regression model to identify the most influential parity factors affecting youth literacy outcomes. Data from UNESCO, the World Bank, and national education statistics were sourced. The findings revealed persistent inequities across gender, disability, geography, and economic status, with particularly pronounced disparities in adult participation, rural attainment, and youth literacy among poorer households. While parity in youth literacy and primary education completion has been largely achieved, inequities persist in secondary education completion and adult education. The findings further revealed that upper secondary completion had a strong positive impact on equity outcomes, whereas disparities in adult participation significantly hindered progress. This study conducted a comprehensive, data-driven examination of educational equity in South Africa. By presenting a novel index approach customised to SDG 4.5, it provided fresh insights into multidimensional inequalities and offered actionable evidence for targeted policy interventions. The study contributes to scholarship on inclusive education while highlighting practical pathways for South Africa to accelerate progress toward equity in line with global education commitments. Full article

Electrical and electronic installations (EEIs) are essential to modern building functionality, yet they remain insufficiently addressed in circular economy (CE) strategies and sustainability frameworks. This study examines how CE principles are understood and applied to EEI in the Flemish construction sector, utilising a national survey of 32 professionals and, among them, five expert interviews. Results confirm that energy-efficient technologies, such as LED lighting and the integration of renewable energy, are widely adopted. In contrast, circular practices, including reuse, modularity, and design for disassembly, remain relatively rare. Respondents acknowledged the importance of lifecycle thinking but reported limited access to practical tools, clear guidelines, and market or regulatory incentives to support its implementation. Circular business models, such as leasing and take-back schemes, are recognised in theory but not widely adopted in practice. At the same time, stakeholder engagement often occurs too late to influence circular outcomes. Overall, the findings suggest that strengthening interdisciplinary cooperation, improving knowledge exchange, and defining clearer project requirements could help translate circular principles into everyday professional practice. This study provides an initial evidence base for improving professional awareness and integrating circular principles into EEI design and procurement, contributing to more circular and sustainable EEI within the construction sector. Full article

Directive (EU) 2024/3019 on urban wastewater treatment requires municipal wastewater treatment plants (WWTPs) to achieve energy neutrality by 2045. This study assessed the energy efficiency of a WWTP in central Poland over eight years (2015–2022), considering influent variability, electricity use and cost, and biogas recovery. The facility served 41,951–44,506 inhabitants, with treated wastewater volumes of 3.08–3.93 million m³/year and a real population equivalent (PE) of 86,602–220,459. Over the study period, the specific energy demand remained stable at 0.92–1.20 kWh/m³ (average 1.04 ± 0.09 kWh/m³), equivalent to 17.4–36.3 kWh/PE∙year. Energy efficiency indicators (EEIs) per pollutant load removed averaged 1.12 ± 0.28 kWh/kgBODrem, 0.53 ± 0.12 kWh/kgCODrem, 1.18 ± 0.36 kWh/kgTSSrem, 12.1 ± 1.5 kWh/kgTNrem, and 62.3 ± 11.7 kWh/kgTPrem. EEI per cubic meter of treated wastewater proved to be the most reliable metric for predicting energy demand under variable influent conditions. Electricity costs represented 4.48–13.92% of the total treatment costs, whereas co-generation from sludge-derived biogas covered 18.1–68.4% (average 40.8 ± 13.8%) of the total electricity demand. Recommended pathways to energy neutrality include co-digestion with external substrates, improving anaerobic digestion efficiency, integrating photovoltaics, and optimizing electricity use. Despite fluctuations in influent quality and load, the ultimate effluent quality consistently complied with legal requirements, except for isolated cases of exceeded phosphorus levels. Full article

Over millions of years of evolution, nature provided tools to optimize different functions in animals and plants. Different strategies observed in nature serve as models for solving complex engineering problems. Additive manufacturing (AM), also known as 3D printing, enables us to produce shapes that would not be possible with traditional subtractive manufacturing. In this way, it is possible to produce complex detailed shapes using an automatic process. Biomimetics involves drawing inspiration from nature and applying it to solve specific engineering challenges, often with the goal of optimization and enhanced performance. Three-dimensional printing enables the replication of complex natural shapes, opening new avenues for innovation. In this paper, we review the state of the art in biomimetics, including studies on mechanical properties, design strategies, manufacturing techniques, and the use of composites. Full article

The Earth’s Radiation Budget (ERB) is a critical component for understanding the planet’s climate system, as it governs the balance between incoming solar energy and outgoing thermal radiation. Accurate monitoring of the ERB, combined with Ocean Heat Content (OHC) measurements, is essential to assess Earth’s Energy Imbalance (EEI) and its implications for global warming. This paper presents new results on the ERB based on data from the Uvsq-Sat and Inspire-Sat nanosatellite missions, which operated from 2021 to 2024. These satellites constitute the first European constellation demonstrator designed for broadband, Wide Field-Of-View (WFOV) measurements of the ERB. While WFOV instruments provide enhanced temporal and spatial coverage, they do not replace the need for Narrow Field-Of-View (NFOV) measurements, such as those provided by the established Clouds and the Earth’s Radiant Energy System (CERES) instruments. Instead, they are designed to complement them. By using data from both the WFOV constellation and CERES instruments to measure Reflected Solar Radiation (RSR) and Outgoing Longwave Radiation (OLR), we estimate the EEI and monitor its evolution. Our analysis reveals a generally good agreement between Uvsq-Sat and CERES data for EEI from 2021 through the end of 2024. Over this period, EEI derived from Uvsq-Sat averaged +0.87 ± 0.23 ${\mathrm{Wm}}^{-2}$, closely matching the recent CERES trend. Both datasets indicate a peak in EEI in mid-2023, followed by a decline throughout 2024, likely reflecting stabilizing feedbacks triggered by the 2023 El Niño event. Importantly, this short-term decline occurred within a sustained upward trend in EEI since 2013, as shown by CERES observations, with solar activity having a negligible impact. Comparisons with OHC measurements confirm ongoing ocean heat accumulation, consistent with the rising decadal trend in EEI. These insights underscore the importance of continuous, high-frequency observations to capture the complex and rapidly evolving processes influencing Earth’s energy balance. Demonstrations using nanosatellites at different local times illustrate the advantages of small satellite constellations for improved monitoring frequency and coverage, particularly for variables that change over short time scales, such as RSR, also known as Outgoing Shortwave Radiation (OSR). Full article

The transition to passenger car electrification is a crucial step in China’s strategic efforts to achieve carbon peak and carbon neutrality. However, previous research has not considered the variances in vehicle models. Hence, this study aims to fill this gap by comparing the carbon emission reduction and economic feasibility of battery electric vehicles (BEVs) in the Chinese market, taking into account different powertrains, vehicle segments, classes, and driving ranges. Next, the study identifies the most cost-effective BEV within each market segment, employing life-cycle assessment and life cycle cost analysis methods. Moreover, at different levels of technological development, we construct three low-carbon measures, including electricity decarbonization (ED), energy efficiency improvement (EEI), and vehicle lightweight (LW), to quantify the emission mitigation potentials from different carbon reduction pathways. The findings indicate that BEVs achieve an average carbon reduction of about 31.85% compared to internal combustion engine vehicles (ICEVs), demonstrating a significant advantage in carbon reduction. However, BEVs are not economically competitive. The total life cycle cost of BEVs is 1.04–1.68 times higher than that of ICEVs, with infrastructure costs accounting for 18.8–57.8% of the vehicle’ s life cycle costs. In terms of cost-effectiveness, different models yield different results, with sedans generally outperforming sport utility vehicles (SUVs). Among sedans, both A-class and B-class sedans have already reached a point of cost-effectiveness, with the BEV400 emerging as the optimal choice. In low-carbon emission reduction scenarios, BEVs could achieve carbon reduction potentials of up to 45.3%, 14.9%, and 9.0% in the ED, EEI, and LW scenarios, respectively. Thus, electricity decarbonization exhibits the highest potential for mitigating carbon emissions, followed by energy efficiency improvement and vehicle lightweight. There are obvious differences in the stages of impact among different measures. The ED measure primarily impacts the waste treatment process (WTP) stage, followed by the vehicle cycle, while the EEI measure only affects the WTP stage. The LW measure has a complex impact on emission reductions, as the carbon reductions achieved in the WTP stage are partially offset by the increased carbon emissions in the vehicle cycle. Full article

Surface urban heat island (SUHI) effects are intensifying in arid desert cities due to rapid urban expansion, limited vegetation, and increasing impervious and barren land surfaces. This leads to serious ecological and socio-environmental challenges in cities. This study investigates the relationship between landscape composition and land surface temperature (LST) in Phoenix and Tucson, two rapidly growing cities located in the Sonoran Desert of the southwestern United States. Landsat-9 OLI-2/TIRS-2 satellite imagery was used to derive the LST value and calculate spectral indices. A multi-resolution grid-based approach was applied to assess spatial correlations between land cover and mean LST across varying spatial scales. The strongest positive correlations were observed with barren land, followed by impervious surfaces, while green space showed a negative correlation. Furthermore, the Urban Thermal Field Variation Index (UTFVI) and the Ecological Evaluation Index (EEI) assessments indicated that over one-third of both cities are exposed to strong SUHI effects and poor ecological quality. The findings highlight the critical need for ecologically sensitive urban planning, emphasizing the importance of the morphological structure of cities, the necessity of planning holistic blue–green infrastructure systems, and the importance of reducing impervious surfaces to decrease LST, mitigate SUHI and SUHI impacts, and increase urban resilience in desert environments. These results provide evidence-based guidance for landscape planning and climate adaptation in hyper-arid urban environments. Full article

The spatial morphology of traditional villages stems from prolonged interactions between socio-economic conditions and the regional natural environment under specific historical contexts. Over time, these settlements have acquired distinct spatial patterns through continuous adaptation to their surrounding ecosystems. Nevertheless, accelerated urbanization now exerts dual pressures—disrupting the spatial order and degrading natural ecosystems. In this context, an integrated analysis of the relationship between village spatial patterns and ecological conditions is essential for elucidating their formative mechanisms. The Xiangjiang River Basin is Hunan’s cultural core, and the spatial distribution of traditional villages is directly related to environmental variables. This study uses bivariate spatial autocorrelation and geographically weighted regression to investigate the relationship between the spatial distribution of traditional villages and ecological environmental appropriateness. The findings indicate the following: (1) The spatial distribution density of traditional villages in the Xiangjiang River Basin exhibits a negative correlation with the Ecological Environment Index (EEI), as evidenced by a Moran’s I value of −0.228. This suggests that traditional villages tend to be less concentrated in areas with a higher ecological suitability. (2) Among natural factors, the Relief Degree of Land Surface (RDLS), the Temperature Humidity Index (THI), and the Land Cover Index (LCI) display positive correlations with village density, with regression coefficients of 0.865, 0.003, and 11.599, respectively. In contrast, the Water Resource Index (WRI) shows a negative correlation, with a coefficient of −6.448, and (3) the impact of ecological suitability factors on village distribution is spatially heterogeneous: microtopographic variation is the primary driver in flat terrains, whereas the ecological carrying capacity exerts a greater influence in mountainous areas. These findings clarify the role of ecological suitability in shaping the spatial characteristics of traditional villages and provide a scientific basis for developing protection strategies that integrate ecological sustainability with cultural–heritage preservation. Full article

The industrial sector’s increasing electricity demand (direct and indirect), driven by the electrification of processes and the production of green hydrogen, poses significant challenges for achieving decarbonisation goals. While switching to renewable electricity and offsetting emissions appears straightforward, the gap between current generation capacities and projected demand remains substantial. This article analyses survey data from the Energy Efficiency Index of German Industry (EEI), revealing that manufacturing companies aim to reduce 22.1% of their 2019 emissions by 2025 and 27.3% by 2030, primarily through on-site measures. However, given the slow pace of renewable capacity expansion and the increasing electrification across sectors, it becomes evident that the envisaged green electricity share of 80% by 2030 will require far more capacity than currently planned. To address this challenge, the article introduces a decarbonisability factor to better assess on-site versus off-site measures, highlighting the need for a strategic sequencing of efficiency and renewable generation. To support decision-makers, the article calls for improved data collection and periodic reassessment to account for changing geopolitical and economic conditions. Full article

Earth’s energy imbalance (EEI) is a major indicator of climate change. Its metrics are top of the atmosphere radiation imbalance (EEI TOA) and net internal heat uptake. Both EEI and temperature are expected to respond gradually to forcing on annual timescales. This expectation was tested by analyzing regime changes in the inputs to EEI TOA along with increasing ocean heat content (OHC). Outward longwave radiation (OLR) displayed rapid shifts in three observational and two reanalysis records. The reanalysis records also contained shifts in surface fluxes and temperature. OLR, outward shortwave radiation (OSR) and TOA net radiation (Net) from the CERES Energy Balanced and Filled Ed-4.2.1 (2001–2023) record and from 27 CMIP5 historical and RCP4.5 forced simulations 1861–2100, were also analyzed. All variables from CERES contained shifts but the record was too short to confirm regime changes. Contributions of OLR and OSR to net showed high complementarity over space and time. EEI TOA was −0.47 ± 0.11 W m⁻² in 2001–2011 and −1.09 ± 0.11 W m⁻² in 2012–2023. Reduced OSR due to cloud feedback was a major contributor, coinciding with rapid increases in sea surface temperatures in 2014. Despite widely varying OLR and OSR, 26/27 climate models produced stable regimes for net radiation. EEI TOA was neutral from 1861, shifting downward in the 26 reliable records between 1963 and 1995, with 25 records showing it stabilizing by 2039. To investigate heat uptake, temperature and OHC 1955/57–2023 was analyzed for regime change in the 100 m, 700 m and 2000 m layers. The 100 m layer, about one third of total heat content, was dominated by regimes. Increases became more gradual with depth. Annual changes between the 700 m layer and 1300 m beneath were negatively correlated (−0.67), with delayed oscillations during lag years 2–9. Heat uptake at depth is dynamic. These changes reveal a complex thermodynamic response to gradual forcing. We outline a complex arrangement of naturally evolved heat engines, dominated by a dissipative heat engine nested within a radiative engine. EEI is a property of the dissipative heat engine. This far-from-equilibrium natural engine has evolved to take the path of least resistance while being constrained by its maximum power limit (~2 W m⁻²). It is open to the radiative engine, receiving solar radiation and emitting scattered shortwave and longwave radiation. Steady states maximize entropy within the dissipative engine by regulating spatial patterns in surface variables that influence outgoing OLR and OSR. Regime shifts to warmer climates balance the cost of greater irreversibility with increased energy rate density. The result is the regulation of EEI TOA through a form of thermodynamic metabolism. Full article

Waste polyethylene terephthalate (PET) bottles represent 12% of global plastic waste; however, only 9% are recycled. Hydrothermal processing presents the opportunity to upcycle waste PET into its monomers, particularly, terephthalic acid (TPA). In this study, post-consumer PET sparkling water bottles were neutrally hydrolysed via a hydrothermal process operating within a temperature range of 220–270 °C, a residence time of 30–90 min, and autogenous pressure of 25–90 bar. Under these conditions, the TPA yield varied between 7.34 and 81.05%, and the maximum TPA yield was obtained at 250 °C, 90 min, and 40 bar. The process temperature had a more profound impact on the PET conversion and TPA yield than the residence time. The values of the environmental factor (EF) were found to be 0.017–0.106, which were comparable to those of bulk chemicals (EF < 1). With the chosen operating conditions, the environmental energy impact (EEI) of TPA production was estimated to be 5.29 × 10⁴ °C min. The findings demonstrate that neutral hydrolysis is a feasible approach for converting PET polymers into monomers under mild environmental conditions. In addition, a GCMS analysis of the aqueous-phase product revealed a notable increase in the secondary degradation products of TPA, such as benzoic acid, rising from 66.4% to 75.7% as the process temperature increased from 220 °C to 270 °C. The degradation mechanisms of PET were found to be decarboxylation, dehydration, and oxidation. The dominant mechanism was found to be a decarboxylation reaction. Full article

Natural compounds incorporated into hydrogel materials have been widely used to support wound healing due to their numerous properties. The aim of this research was to produce hydrogel biomaterials with the addition of adjuvants, such as sodium alginate and polyethylene glycol diacrylate (PEGDA) with the addition of ethylene ginger extract (EEI). A thermogravimetric (TG) study, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), water absorption testing and microscopic analysis were carried out to determine the properties of the developed dressing. The conducted research showed that the 4%Alg/12%PEGDA hydrogel was characterized by the best water absorption values and the slowest weight loss as a function of temperature. Additionally, the 4%Alg/12%PEGDA hydrogel had the best ability to dissipate stress in its structure. It was found that the addition of the ginger modifier had a negative effect on the water absorption values. Hydrogel containing 4%Alg 12%PEGDA 12%EEI showed the best hydrophilic properties and the highest ionic conductivity. The studies conducted showed that both the addition of PEGDA and EEI to hydrogels affects the increase in acidity of dressings. This is important because maintaining an acidic wound microenvironment is a potential therapeutic strategy for wound management. Therefore, although further research is needed, it is possible that 4%Alg 12%PEGDA 12%EEI hydrogel could be used as a high-performance wound dressing. Full article