Search Results (7,758)

Large-scale wind power grid-connected systems can trigger the risk of power system instability. In order to enhance the stability margin of grid-connected systems, this paper accurately characterizes the topology of the global boundary of stability domain (BSD) of the grid-connected system based on BSD theory, using the method of combining the manifold topologies and singularities at infinity. On this basis, the effect of large-scale doubly fed induction generators (DFIGs) replacing synchronous units on the BSD of the system is analyzed. Simulation results based on the IEEE 39-bus system indicate that the negative impedance characteristics and low inertia of DFIGs lead to a contraction of the stability domain. The principle of singularity invariance (PSI) proposed in this paper can effectively expand the BSD by adjusting the inertia and damping, thereby increasing the critical clearing time by about 5.16% and decreasing the dynamic response time by about 6.22% (inertia increases by about 5.56%). PSI is superior and applicable compared to traditional energy functions, and can be used to study the power angle stability of power systems with a high proportion of renewable energy. Full article

Finite-time thermodynamics (FTT) describes the study of thermodynamic processes that take place in finite time. Due to the finite-time requirement, in general the system cannot move from equilibrium state to equilibrium state. As a consequence, excess entropy is generated, available work is reduced, and/or the maximally achievable efficiency is not achieved; minimizing these negative side-effects constitutes an optimal control problem. Particularly challenging are processes and cycles that involve phase transitions of the working fluid material or the target material of a synthesis process, especially since most materials reside on a highly complex energy landscape exhibiting alternative metastable phases or glassy states. In this perspective, we discuss the issues and challenges involved in dealing with such materials when performing thermodynamic processes that include phase transitions in finite time. We focus on thermodynamic cycles with one back-and-forth transition and the generation of new materials via a phase transition; other systems discussed concern the computation of free energy differences and the general applicability of FTT to systems outside the realm of chemistry and physics that exhibit cost function landscapes with phase transition-like dynamics. Full article

To support carbon peaking and neutrality goals in the city transportation sector, this paper accounts for CO₂ emissions from the transport sector in Xuzhou City, North Jiangsu Province, from 1995 to 2023. This study explores the relationship between transport-related carbon emissions and economic growth, using the TAPIO decoupling index. Meanwhile, a carbon emission prediction model based on the STIRPAT framework is constructed, with scenario analysis applied to forecast future emissions. Results show three decoupling stages: the first, dominated by weak and expansive negative decoupling, reflects extensive economic growth; the second features weak decoupling with expansive coupling, indicating a more environmentally coordinated phase; the third transitions from expansive negative decoupling and weak decoupling to strong decoupling and expansive coupling, suggesting a shift in development patterns. Under the baseline, low-carbon, and enhanced low-carbon scenarios, by 2030, the CO₂ emissions of the transportation industry in Xuzhou will be 10,154,700 tons, 9,072,500 tons, and 8,835,000 tons, respectively, and the CO₂ emissions under the low-carbon scenario and the enhanced low-carbon scenario will be reduced by 10.66% and 13.00%, respectively. Based on these findings, the study proposes carbon reduction strategies for Xuzhou’s transport sector, focusing on policy regulation, energy use, and structural adjustments. Full article

Indoor horticulture requires a substantial quantity of electricity to meet crops extended photoperiodic requirements for optimal photosynthetic rate. Simultaneously, global electricity costs have grown dramatically in recent years, endangering the sustainability and profitability of indoor vertical farms and/or modern greenhouses that use artificial lighting systems to accelerate crop development and growth. This study investigates the growth rate and physiological development of cherry tomato plants cultivated in a pilot indoor vertical farm at the Agricultural University of Athens’ Laboratory of Farm Structures (AUA) under continuous and disruptive lighting. The leaf physiological traits from multiple photoperiodic stress treatments were analyzed and utilized to estimate the plant’s tolerance rate under varied illumination conditions. Four different photoperiodic treatments were examined and compared, firstly plants grew under 14 h of continuous light (C-14L10D/control), secondly plants grew under a normalized photoperiod of 14 h with intermittent light intervals of 10 min of light followed by 50 min of dark (NI-14L10D/stress), the third treatment where plants grew under 14 h of a load-shifted energy demand response intermittent lighting schedule (LSI-14L10D/stress) and finally plants grew under 13 h photoperiod following of a load-shifted energy demand response intermittent lighting schedule (LSI-13L11D/stress). Plants were subjected also under two different light spectra for all the treatments, specifically WHITE and Blue/Red/Far-red light composition. The aim was to develop flexible, energy-efficient lighting protocols that maintain crop productivity while reducing electricity consumption in indoor settings. Results indicated that short periods of disruptive light did not negatively impact physiological responses, and plants exhibited tolerance to abiotic stress induced by intermittent lighting. Post-harvest data indicated that intermittent lighting regimes maintained or enhanced growth compared to continuous lighting, with spectral composition further influencing productivity. Plants under LSI-14L10D and B/R/FR spectra produced up to 93 g fresh fruit per plant and 30.4 g dry mass, while consuming up to 16 kWh less energy than continuous lighting—highlighting the potential of flexible lighting strategies for improved energy-use efficiency. Full article

Efficient plastic waste end-of-life management is a serious worldwide environmental issue motivated by growing waste production and negative effects of wrongful disposal. This study presents a comparative overview of plastic waste management regimes within the European Union (EU), the United States of America (USA), and Romania, ranked with circular economy goals. By using the United States Environmental Protection Agency (US EPA) Waste Reduction Model (WARM), version 16, the study provides a quantified score to greenhouse gas (GHG) emissions within three large options of management: recycling, energy recovery through combustion, and landfilling. The model setup utilizes region-specific information on legislation, base technology, and recycling efficiency. The outcomes show that recycling always entails net GHG emissions reductions, i.e., −4.49 kg CO_2e/capita/year for EU plastic waste and −20 kg CO_2e/capita/year for USA plastic waste. Combustion and landfilling have positive net emissions from 1.76 to 14.24 kg CO_2e/capita/year. Economic indicators derived from the model also show significant variation: salaries for PET management amounted to USD 2.87 billion in the EU and USD 377 million in the USA, and tax collection was USD 506 million and USD 2.01 billion, respectively. The conclusions highlight the wider environmental and socioeconomic benefits of recycling and reinforce its status as a cornerstone of circular-economy sustainable plastic waste management and a strategic element of national development agendas, with special reference to Romania’s national agenda. Full article

As the climate problem is getting more and more serious and the “low-carbon revolution” of globalization is emerging, the logistics industry, as a high-end service industry, must also take the road of low-carbon development. Improving logistics carbon emission efficiency (LCEE) is gradually becoming an inevitable choice to maintain sustainable social development. The study uses the Super-SBM (Super-Slack-Based Measure) model to evaluate the urban LCEE from 2013 to 2022, explores the contribution of efficiency changes and technological progress to LCEE through the decomposition of the GML (Global Malmquist–Luenberger) index, and reveals the influence of digital transformation and energy consumption structure on LCEE by using the Spatial Durbin Model, concluding as follows: (1) LCEE declines from east to west, with large regional differences. (2) LCEE has steadily increased over the past decade, with slower growth from east to west. It fell in 2020 due to COVID-19 but has since recovered. (3) LCEE shows a catching-up effect among the three major regions, with technological progress being a key driver of improvement. (4) LCEE has significant spatial dependence. Energy consumption structure has a short-term negative spillover effect, while digital transformation has a positive spillover effect. Full article

The current work is established with the object of modifying the source of Fenton system and substituting iron source as a catalyst with magnetite/potato peels composite material (POT400-M) to be an innovative solar photocatalyst. The structural and morphological characteristics of the material are assessed through X-ray diffraction (XRD) and scanning electron microscopy (SEM). The technique is applied to treat oil spills that pollute seawater. The effectiveness of the operating parameters is studied, and numerical optimization is applied to optimize the most influential parameters on the system, including POT400-M catalyst (47 mg/L) and hydrogen peroxide reagent (372 mg/L) at pH 5.0, to maximize oil removal, reaching 93%. Also, the aqueous solution and wastewater temperature on the oxidation reaction is evaluated and the reaction exhibited an exothermic nature. Kinetic modeling is evaluated, and the reaction is found to follow the second-order kinetic model. Thermodynamic examination of the data exhibits negative enthalpy (∆H′) values, confirming that the reaction is exothermic, and the system is verified to be able to perform at the minimal activation energy barrier (−51.34 kJ/mol). Full article

With the proposal of China’s “dual carbon” goal, the carbon market has become a vital tool for controlling carbon emissions. This study constructs a system dynamics model encompassing carbon trading, the economy, energy, population, and the environment, and conducts simulation analysis against the backdrop of China’s national carbon market’s implementation. The results indicate that the implementation of China’s national carbon market significantly promotes carbon emissions reduction, albeit at the cost of some economic development in the short term. However, the suppressive effect of the carbon market on carbon emissions is stronger than its negative impact on economic growth. The effects of carbon reduction strengthen with increases in carbon price, quota auction, CCER price, penalty severity, and the quota reduction rate and weaken with a higher CCER offset ratio. A moderate reduction in the tightening quota reduction rate is more conducive to achieving coordinated development across the multiple objectives of carbon reduction, economic development, and energy structure. Under the constraints of multiple objectives involving carbon reduction, economic development, and energy structure, the reasonable range for carbon prices is between CNY 77.9 and CNY 118.9 per ton, with the maximum quota auction of 23.4%. Additionally, the reasonable range for the quota reduction rates is between 0.84% and 2.18%, with the penalty severity set at 7. Full article

Insulin resistance is a fundamental pathophysiological mechanism contributing to the development of type 2 diabetes and metabolic syndrome. Recently, attention has focused on mitochondria’s role in glucose and lipid metabolism. Mitochondrial dysfunction is strongly associated with impaired energy metabolism and elevated oxidative stress. We investigated the mitochondrial DNA (mtDNA) copy number in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) in insulin-sensitive (IS) and insulin-resistant (IR) individuals. Twenty-seven paired adipose tissue biopsies were obtained during elective abdominal surgery. DNA and RNA were extracted, and mtDNA copy number was quantified using Real-Time PCR. We found that mtDNA content in VAT was approximately two-fold lower than in SAT. Furthermore, in IR individuals, mtDNA copy number was significantly reduced in both SAT and VAT compared to IS subjects. A strong positive correlation was observed between mtDNA content in VAT and body mass index (BMI), and a negative correlation was found with the QUICKI index. Additionally, mtDNA copy number in VAT positively correlated with the expression of several genes involved in insulin signalling, lipid metabolism, and other metabolic pathways. These findings underscore the central role of mitochondrial function in VAT in the context of metabolic disorders and suggest that targeting mitochondrial regulation in this tissue may represent a promising therapeutic approach. Full article

Urban metabolism frameworks offer insight into flows of energy, materials, and services in cities, yet tree species selection is seldom treated as a metabolic indicator. In Amman, Jordan, we integrate spatial metabolic metrics to critique monocultural greening policies and demonstrate how species choices forecast long-term urban metabolic performance. Using ENVI-met 5.61 simulations, we compare Melia azedarach, Olea europaea, and Ceratonia siliqua, mainly assessing urban flow related elements like air temperature reduction, CO₂ sequestration, and evapotranspiration alongside rooting depth, isoprene emissions, and biodiversity support. Melia delivers rapid cooling but shows other negatives like a low biodiversity value; Olea offers average cooling and sequestration but has allergenic pollen issues in people as a flow; Ceratonia provides scalable cooling, increased carbon uptake, and has a high ecological value. We propose a metabolic reframing of green infrastructure planning to choose urban species, guided by system feedback rather than aesthetics, to ensure long-term resilience in arid urban climates. Full article

In the context of growing global climate change awareness and intensifying environmental degradation, technological innovation in renewable energy has become a key realization method for sustainable development. This paper uses data samples from 30 provinces, municipalities, and autonomous regions in China (excluding Tibet, Hong Kong, Macao, and Taiwan due to data availability) from 2007–2022, constructs an SFA model to measure carbon emission efficiency, and innovatively investigates the U-shaped impact of technological innovation in renewable energy on carbon emission efficiency along with the moderating effects of informatization level and fiscal decentralization. The empirical findings reveal the following: (1) Technological innovation in renewable energy demonstrates a U-shaped impact on carbon emission efficiency, with a negative impact before inflection point 2.596605 and a positive impact after the inflection point. (2) The informatization level plays a positive regulating role in the impact of technological innovation in renewable energy toward carbon emission efficiency, while fiscal decentralization exerts a negative regulating effect. (3) The impact of technological innovation in renewable energy concerning carbon emission efficiency varies depending on regional differences, industrial structure levels, and technological innovation levels in renewable energy. The conclusions of this paper are helpful for promoting the development of technological innovation in renewable energy, improving carbon emission efficiency, and advancing sustainable socio-economic development. Full article

The use of microwaves (MWs) has been proposed as an energy-efficient method for reducing checking. Along with understanding moisture distribution, it is essential to consider structural characteristics to explain how MWs reduce checking. The influence of MWs on these characteristics depends on the food matrix’s dielectric and viscoelastic properties, which vary significantly between fresh and pre-baked dough. This study investigates the effects of MW treatment applied before (MW-O) or after conventional oven baking (O-MW) on low-fat biscuits that are prone to checking. Color (CIELab), thickness, moisture content and distribution, checking rate, texture, sensory properties, energy consumption and baking time were analyzed. The findings suggest that MWs reduce checking rate by eliminating internal moisture differences, while also changing structural properties, as evidenced by increased thickness and hardness. MW-O eliminated checking (control samples showed 100%) but negatively affected color, texture (increased hardness and breaking work), and sensory quality. The O-MW checking rate (3.41%) was slightly higher than in MW-O, probably due to the resulting different structural properties (less thickness, less hardness and breaking work). O-MW biscuits were the most preferred by consumers (54.76% ranked them first), with color and texture close to the control samples. MW-O reduced total energy consumption by 16.39% and baking time by 25.00%. For producers, these improvements could compensate for the lower biscuit quality. O-MW did not affect energy consumption but reduced baking time by 14.38%. The productivity improvement, along with the reduction in checking and the satisfactory sensory quality, indicates that O-MW could be beneficial for the bakery sector. Full article

In sustainable development studies, a key question is how the abundance of natural resources influences long-run economic growth. However, there is no consensus on this issue. Some literature suggests a negative impact, while other studies find no effect at all, and other research indicates a positive impact. This study aims to examine the relationship between natural resource rents, renewable energy, and economic growth in the Gulf Cooperation Council (GCC) countries over the period from 1990 to 2023. The study utilizes the Method of Moments Quantile Regression (MMQR) to provide reliable findings across different quantiles. We also incorporate a series of control variables, including capital, labor force participation, non-renewable energy, and trade openness. The findings indicate that natural resources rent enhances economic growth in GCC countries, supporting the Rostow hypothesis. Although renewable energy has a positive impact on economic growth, it does not have an effect on natural resource rents. Additionally, capital, labor force participation, non-renewable energy, and trade openness play a critical role in raising economic growth in these countries. Based on the empirical results, this study provides several valuable recommendations for policymakers to enhance the management of natural resources in GCC countries. Full article

The article addresses the question of the relative importance of human population size and growth in relation to the environmental problems of planetary heating and biodiversity loss in the current, Anthropocene era. To what extent could policies to encourage lower fertility be justified, while observing that this subject is an inherently contested one. It is proposed that a helpful distinction can be made between specific threats to habitats and biodiversity, as opposed to those related to global energy use and warming. Pressures of over-population can be important in relation to the former. But with regard to the latter—rising per capita energy usage—reduced fertility has historically been positively, not negatively correlated. A case can be made that the high-fertility nations of sub-Saharan Africa could benefit from culturally respectful fertility reduction policies. However, where planetary heating is concerned, it is the hydrocarbon-based, per capita energy-consumption patterns of already low-fertility populations on the other five inhabited continents that is rather more critical. While it will be helpful to stabilise global human population, this cannot be viewed as a solution to the climate crisis problem of this century. That requires relentless focus on reducing hydrocarbon use and confronting the rising inequality since c.1980 that has been exacerbating competitive materialist consumerism. This involves the ideological negotiation of values to promote a culture change that understands and politically embraces a new economics of both human and planetary balance, equity, and distribution. Students of populations can contribute by re-assessing what can be the appropriate demographic units and measures for policies engaging with the challenges of the Anthropocene. Full article

Given the compromising effect of energy rebound on energy conservation efforts and environmental sustainability, plentiful research has focused on evaluating its size and scope in the past; however, there is a scarcity in the exploration of its potential drivers, especially the impacts of the digital economy. With the accelerating pace of worldwide digitalization, how the digital economy affects the energy rebound effect deserves special attention. We explored the underlying impacts of the digital economy on energy rebound and its influencing mechanisms for the first time in this study based on a panel dataset from China. Results show that most of the regions in China exhibited a partial rebound effect over the period 2007–2022, with an average value of 77.14%. Digital economy development exhibits a threshold effect on energy rebound with regard to energy efficiency improvement. That is, when the energy efficiency is low, digital economy development positively impacts the energy rebound, however, as the energy efficiency increases and surpasses a certain critical threshold, the digital economy can help mitigate the energy rebound effect. Energy prices and environmental regulation present a significant negative impact on energy rebound. Finally, several policy implications are highlighted based on the main findings of this study. Full article