Hasil untuk "Energy conservation"

V. Harish, Arun Kumar

Zeyu Wang, R. Srinivasan

C. Ragan, E. Racker

Abstract 1. The ability to phosphorylate ADP during oxidation of NADH by ubiquinone-1 was restored to the NADH-ubiquinone reductase complex by combining the latter with phospholipids and a hydrophobic protein fraction derived from bovine heart mitochondria. 2. Phosphorylation was abolished by rotenone, uncoupling agents, or rutamycin. The efficiency of ATP formation was as high as 0.5 mole per mole of NADH oxidized under optimal conditions. 3. Reconstitution of phosphorylation had an absolute requirement for phosphatidylethanolamine and a partial requirement for phosphatidylcholine, a molar ratio of approximately 4:1 being optimal. A much more marked requirement for phosphatidylcholine was observed in the presence of low concentrations of cardiolipin (0.05 to 1.5% of the total phospholipid). In the presence of cardiolipin, an equal molar ratio of phosphatidylethanolamine to phosphatidylcholine gave the highest phosphorylation efficiency. 4. The NADH-ubiquinone reductase complex is oriented in the reconstituted vesicles such that approximately 50% of the molecules can react with added NADH. Reaction of all the molecules with NADH occurs in the presence of 0.5% deoxycholate. 5. Phosphorylation efficiency can be significantly improved by purification of the vesicles on sucrose density gradients.

T. Behera, S. K. Mohapatra, U. C. Samal et al.

Wireless sensor networks (WSNs) groups specialized transducers that provide sensing services to Internet of Things (IoT) devices with limited energy and storage resources. Since replacement or recharging of batteries in sensor nodes is almost impossible, power consumption becomes one of the crucial design issues in WSN. Clustering algorithm plays an important role in power conservation for the energy constrained network. Choosing a cluster head (CH) can appropriately balance the load in the network thereby reducing energy consumption and enhancing lifetime. This paper focuses on an efficient CH election scheme that rotates the CH position among the nodes with higher energy level as compared to other. The algorithm considers initial energy, residual energy, and an optimum value of CHs to elect the next group of CHs for the network that suits for IoT applications, such as environmental monitoring, smart cities, and systems. Simulation analysis shows the modified version performs better than the low energy adaptive clustering hierarchy protocol by enhancing the throughput by 60%, lifetime by 66%, and residual energy by 64%.

B. Ozcan, I. Ozturk

Abstract In this study, we analyzed the relationship between renewable energy consumption and economic growth in 17 emerging countries, spanning the period of 1990–2016. The bootstrap panel causality test, allowing for dependence across countries and heterogeneity in slope parameters, developed by Konya (2006) [1] was employed. The results indicated that the neutrality hypothesis does hold for all of the markets studied except for Poland, which confirmed the growth hypothesis. As such, because of the nonexistence of causality running from renewable energy demand to economic growth, energy saving (mitigation) policies do not have any detrimental influence on the growth rates of these 16 emerging economies. For Poland; however, energy conservation policies may have detrimental effects on the country's economic performance level.

N. Dulvy, C. Simpfendorfer, Lindsay N. K. Davidson et al.

Yao Yao, Kris Ivanovski, J. Inekwe et al.

Abstract We examine the effect of human capital on energy consumption for a panel of OECD economies over the period 1965–2014. Our preferred results, which account for cross-sectional dependence and structural breaks, suggest that a one standard deviation increase in human capital reduces aggregate energy consumption by 15.36%. When we distinguish between clean and dirty energy consumption, we find that human capital generates significant positive externalities for the environment. Specifically, we find that a one standard deviation increase in human capital is associated with a 17.33% decrease in dirty energy consumption and an 85.54% increase in clean energy consumption. Our findings reinforce the social benefits of investing in human capital and suggest a promising avenue for energy conservation without impeding economic growth.

Ramhari Poudyal, P. Loskot, Rabindra Nepal et al.

Abstract Nepal has been suffering from a serious energy crisis for decades. It has severely affected its economic, social and political developments. Owing to the continuously evolving energy situation in Nepal, and the recent progress in renewable energy technologies, this study aims to provide an up to date perspective on the current energy crisis in Nepal. In particular, the current energy production and consumption profiles are reviewed, and the main factors contributing to a widening gap between the energy supply and demand are identified. These factors concern delayed and overpriced hydropower projects, outdated and insufficient energy infrastructure, transmission and distribution losses, energy theft, deficient energy management, lack of energy conservation, low efficiency of equipment, unsustainable energy pricing strategies and unsatisfying energy market regulations. Other essential factors worsening the energy crisis can be attributed to specific geographical and geopolitical problems, the strong dependence on energy imports, and inadequate exploitation of the vast amounts of renewable energy resources. The status of existing and planned large hydropower projects is summarized. The recent policies and investment initiatives of the Nepalese government to support green and sustainable energy are discussed. Furthermore, a long-term outlook on the energy situation in Nepal is outlined using the energy modeling software LEAP in order to show how to exploit the tremendous renewable energy resources in Nepal. Our findings suggest that renewable resources are crucial not only for mitigating the present energy crisis, but also to ultimately provide energy independence for Nepal by establishing reliable and secure sources of energy.

L. Steg

Anagha Darshan, Naman Girdhar, Rohan Bhojwani et al.

Electricity is a crucial part of our everyday lives. A limited number of resources can be utilized to generate power; hence, one must save these resources or electricity for future utilization. This is only possible by using energy most efficiently. For sustainable development and energy conservation, energy auditing plays an indispensable role. The energy audit is an extensive study that helps to identify energy use among different services and provides opportunities for energy conservation. The literature showed various energy audits conducted at various locations with its analysis. Few were shown that the appliances are responsible for high energy consumption, and few talked about the cost analysis with energy-saving methodologies. This work is proposed to combine the integration of renewable energy sources in a building and the cost-saving due to energy-efficient appliances. This paper tries to observe, infer, and analyze the patterns of energy usage of a residential complex and various measures to reduce energy consumption and cost-saving. A case study is included to analyze the reduction in consumption of energy per unit to make the building energy efficient. A feasibility study is executed to observe the increments in costs. Calculations for auditing will reduce the building’s carbon footprint and benefit residents in the form of cost savings in the long run.

Wenbo Li, Pengcheng Sha, Chao Li et al.

When sub-synchronous oscillations occur in the doubly fed induction generator-based wind farm connected to series-compensated transmission network, the transient behaviors are related to the operational conditions, including the number of online turbines, wind speed, level of series compensation, and control parameters. This paper proposes an adaptive damping device for sub-synchronous oscillations and its control strategy, which addresses suppression requirements under time-varying operational conditions. Unlike in conventional methods, this device is connected in series to transmission line. Suppression control is automatically activated when sub-synchronous oscillations are detected. Furthermore, the proposed strategy behaves as controlled voltage source that is only effective at sub-synchronous frequencies and does not affect normal operations. The effectiveness of the proposed strategy is validated through simulations of the Guyuan wind farm in PSCAD. Results demonstrate significant sub-synchronous oscillation suppression effects in different operational cases, especially those triggered by the interaction between the series-compensated capacitor and the converter controller.

Shiva Khanal, Rachael H. Nolan, Belinda E. Medlyn et al.

Abstract The Central Himalayas, characterized by one of the most pronounced elevation gradients globally, harbor forest stands of high carbon density. With estimated forest aboveground biomass (AGB) densities of up to 1000 t ha−1, these forests are among the most carbon-rich ecosystems within the Himalayas and high mountain ranges globally. However, existing global and regional models of forest carbon distribution fail to accurately capture the remarkable carbon density observed in these Himalayan forest stands. Our objective was to quantify how fine-scale topoclimatic conditions influence the spatial variability of AGB, with the aim of identifying the environmental factors that contribute to the high carbon density observed in high mountain forests of Nepal. Our analysis focused on quantifying the contribution of terrain-driven variation in climatic energy and water availability in creating favourable site conditions for carbon-dense forests. We found that extreme forest carbon density is associated with distinct topographic settings related to slope, aspect and curvature that provide a combination of adequate levels of both climatic energy and water availability, while forest carbon was reduced in topographic positions associated with high likelihood of disturbance such as avalanches and mass movements. Our findings shed light on the intricate relationship between topoclimatic factors and conditions for carbon storage in high-elevation forests, providing valuable insights for conservation and management strategies in mountainous regions.

WANG Xiaoyu, HU Jingyuan, WU Ruoyu, WANG Shu, ZHAI Yujia

[Purpose/Significance] In the contemporary era of rapid technological advancement, understanding the intrinsic linkages between scientific research and technological innovation is critical for guiding strategic decision-making, optimizing resource allocation, and promoting effective technology transfer. Scientific publications and patents represent two complementary yet heterogeneous knowledge sources, with distinct linguistic styles, terminologies, and documentation structures, which often create a significant semantic gap. Traditional methods of linking scientific and technological (S&T) knowledge rely primarily on lexical overlap, keyword co-occurrence, or citation analysis. These methods are limited in their ability to capture deeper semantic relationships, particularly across non-homologous texts. To address this challenge, this study proposes a novel approach leveraging large language models (LLMs) for data augmentation, aiming to uncover latent semantic associations between research paper topics and patent topics. The key innovation of this work lies in using LLMs not merely for text generation but as a semantic bridge to enhance cross-domain knowledge alignment, thereby advancing the methodological toolkit for science-technology linkage studies. This approach offers potential contributions to knowledge mapping, thematic analysis, and strategic innovation management, particularly in areas where domain-specific terminology or conceptual divergence hampers conventional analyses. [Method/Process] The proposed method employs ChatGPT-4 as a knowledge-enriched intermediary to generate semantically enhanced textual variants of existing S&T documents in the energy-saving domain. Specifically, the LLM was used to perform synonym-based paraphrasing, expansion, and semantic inference on research paper abstracts and patent summaries, producing augmented texts that retain domain relevance while highlighting latent semantic connections. These enhanced texts were used to extract features that were subsequently incorporated into a non-patent citation prediction task, which serves as a practical evaluation of the method's effectiveness. By comparing predicted associations against existing citation links, the study assesses the capacity of LLM-derived features to capture cross-domain topic relatedness beyond lexical similarity. The approach relies on the theoretical premise that LLMs can model high-level semantic patterns, enabling the inference of conceptual correspondence even when explicit terminology differs between scientific and technological texts. [Results/Conclusions] The experimental validation process involved four baseline models, and it was found that features derived from the augmented texts consistently improved prediction performance. The area under the ROC curve (AUC) increased by 13.91%, 16.90%, 16.21%, and 15.69% across the four models, respectively, demonstrating the efficacy of LLM-based data augmentation in bridging the semantic gap between S&T knowledge. These results suggest that the method can uncover latent topic associations, facilitate cross-domain term alignment, and support knowledge discovery tasks that conventional lexical-based approaches may overlook. However, the study is limited by its focus on a single application domain, leaving open questions regarding generalizability across multiple S&T fields. Future work should extend the methodology to diverse domains, investigate the robustness of the LLM-generated semantic bridges, and explore automated mechanisms for scaling cross-domain knowledge integration. Overall, this research provides a promising framework for enhancing the semantic connectivity of heterogeneous knowledge sources. This contributes to a broader understanding of the interactions between science and technology and informs data-driven strategies for managing research and innovation.

LUO Gang, XIAO Xiao, WU Di, JISHA Ri-fu, LU Jun

[Objective] This study aims to investigate the dramatic changes in water-sediment processes within the Jinsha River reservoir area following the impoundment and operation of the Wudongde and Baihetan cascade hydropower stations. Using multi-source observational data, the study reveals the variation patterns of water and sediment fluxes between the two dams, the spatiotemporal distribution characteristics of riverbed erosion and deposition, and their driving mechanisms. The findings provide scientific support for reservoir safety operation, navigation channel management, and ecological conservation. [Methods] The study was conducted using runoff-sediment transport data from 2015 to 2023 at the Wudongde and Baihetan hydrological stations, fixed cross-sectional topographic surveys from 2016 to 2023, and hydrodynamic measurements collected downstream of the Wudongde Dam in 2023. Water-sediment relationship analysis was employed to examine the response patterns between runoff and sediment transport. Erosion and deposition volumes were calculated using the cross-sectional method, with 825 m water level as the reference and the channel storage volume estimated via the frustum formula. Spatial variations of erosion and deposition were quantified by overlaying thalweg line and comparing morphological changes of typical cross-sections (JC199, JC153, JC126). [Results] 1) Water-sediment flux variations: Annual runoff exhibited a slight decrease, 2% at the Wudongde station and 17.8% at the Baihetan station. Annual sediment transport plummeted by more than 90%, primarily due to the “cumulative sediment retention effect” of upstream reservoirs. Intra-annual runoff distribution demonstrated a “peak-shaving and valley-filling” pattern, with a 22%-48% increase in December and a 16%-38% decrease in July. Sediment transport was concentrated from June to October (accounting for over 63%), yet monthly averages dropped by more than 95%. A progressive downstream sedimentation trend was observed in September. 2) Spatiotemporal evolution of erosion and deposition: erosion dominated during dry season (October-May), while deposition dominated the wet season (May-October). From 2021 to 2023, a net deposition volume reached 12.63 million m3, showing an overall cumulative trend. Spatially, a strong erosion zone formed at the reservoir tail driven by the high-kinetic-energy discharges from the Wudongde Dam. The core deposition area in the main reservoir was found 25-75 km upstream of the dam. In the tributary-affected zone, the Heishui River confluence showed prominent deposition. 3) Driving mechanisms of erosion and deposition: In terms of hydrodynamic forces, erosion was triggered by high flow velocities and strong sediment-carrying capacities within 20 km downstream of the Wudongde Dam, while beyond this zone, deposition was promoted by slower flows and weaker sediment-carrying capacities. Regarding tributary replenishment, tributaries such as the Pudu River, Xiaojiang River, and Heishui River contributed an average annual sediment transport of 5.73 million tons (2011-2022), accounting for over 46% of the deposition volume in the reservoir area. [Conclusions] The operation of cascade hydropower stations has restructured the water-sediment process. Although the runoff volume decreased slightly, its intra-annual redistribution was significant, and the sediment transport plummeted by 96% due to the “cumulative sediment retention effect”, with sediment being concentrated in flood season. The erosion and deposition in the reservoir area exhibit a spatial pattern of “erosion at the tail and deposition in the head”. The reservoir tail is eroded by the discharged flow, while the main reservoir experiences deposition due to reduced flow velocity and tributary replenishment, with the confluence of the Heishui River being a key source of deposition. A clear long-term deposition trend is observed, and it is necessary to focus on the high-risk deposition zone 25-75 km upstream of the dam and the sections with drastic morphological changes at tributary estuaries. These findings provide a quantitative basis for the joint operation of cascade reservoirs, navigation channel maintenance, and sediment management.

Jiaxin Tan, Yulian Liang, Sufang Yu et al.

Carbon Emission Efficiency (CEE) serves as a crucial metric for assessing regional economic development and carbon mitigation. Enhancing CEE promotes synergy between economic growth and emission reduction, accelerating socio-economic green transformation. As China's first cross-basin ecological civilization pilot zone, the Pearl River-Xijiang Economic Belt (PXEB) exhibits significant upstream-downstream disparities in CEE, reflecting varying capacities to balance carbon reduction, economic growth, and ecological conservation. Investigating CEE determinants (including socio-economic and policy factors) is vital for designing spatially differentiated strategies aligning basin-wide sustainability with local development needs. Using 2005–2020 panel data from 67 PXEB districts, this study applies the SBM-DDF model and the Global Malmquist-Luenberger index to measure CEE, with GTWR modeling analyzing six influencing factors. Key findings: (1) During 2006–2020, PXEB's CEE showed fluctuating growth, with upstream areas having greater improvement potential. Upstream inter-county disparities constituted the primary source of regional imbalances. (2) CEE transition dynamics are spatially heterogeneous, where neighboring areas' improvements promote local upward shifts and curb declines within specific regional typologies. (3) Economic development level is the strongest driver of CEE improvement, while energy intensity constitutes the main barrier to enhanced CEE in the PXEB. This study comprehensively evaluates PXEB's CEE through dynamic-static dimensions, systematically examines drivers' spatiotemporally heterogeneous impacts, and clarifies mechanisms linking factors like population density to CEE, offering scientific support for tailored emission reduction policies.

G. Xing, Xiaorui Wang, Yuanfang Zhang et al.

Yang Ge, Qingping Li, Xin Lv et al.

To facilitate the recovery of natural gas hydrate (NGH) deposits in the South China Sea, we have designed and developed the world's largest publicly reported experimental simulator for NGH recovery. This system can also be used to perform CO2 capture and sequestration experiments and to simulate NGH recovery using CH4/CO2 replacement. This system was used to prepare a shallow gas and hydrate reservoir, to simulate NGH recovery via depressurization with a horizontal well. A set of experimental procedures and data analysis methods were prepared for this system. By analyzing the measurements taken by each probe, we determined the temperature, pressure, and acoustic parameter trends that accompany NGH recovery. The results demonstrate that the temperature fields, pressure fields, acoustic characteristics, and electrical impedances of an NGH recovery experiment can be precisely monitored in real time using the aforementioned experimental system. Furthermore, fluid production rates can be calculated at a high level of precision. It was concluded that (1) the optimal production pressure differential ranges from 0.8 to 1.0 MPa, and the wellbore will clog if the pressure differential reaches 1.2 MPa; and (2) during NGH decomposition, strong heterogeneities will arise in the surrounding temperature and pressure fields, which will affect the shallow gas stratum.

Binbin Zhang, Mengxin Jia, Chaobo Chen et al.

This study proposes a wind farm active power dispatching (WFAPD) algorithm based on the grey incidence method, which does not rely on an accurate mathematical model of wind turbines. Based on the wind turbine start-stop data at different wind speeds, the weighting coefficients, which are the participation degrees of a variable speed system and a variable pitch system in power regulation, are obtained using the grey incidence method. The incidence coefficient curve is fitted by the B-spline function at a full range of wind speeds, and the power regulation capacity of all wind turbines is obtained. Finally, the WFAPD algorithm, which is based on the regulating capacity of each wind turbine, is compared with the wind speed weighting power dispatching (WSWPD) algorithm in MATLAB. The simulation results show that the active power fluctuation of the wind farm is smaller, the rotating speed of wind turbines is smoother, and the fatigue load of high- speed turbines is effectively reduced.

Yitong Yin, Gang Lin, Dong Jiang et al.

In this work, based on the concept of collaborative water–energy development, a multi-scenario system dynamics simulation model of a water–energy coupling system was constructed by using the system dynamics modeling method. The model was composed of four subsystems: society, economic, water resources, and energy. Taking Ningbo City as the research location to run the simulation model, the analysis of the validity of the model showed that the relative error between the historical data and the simulation results of the model was less than 10%, which proved that the model passed the test. In this paper, based on the scenario of business an usual (BAU), three scenarios of water-saving scenario (WSS), energy-saving scenario (ESS), and comprehensive savings (CS, the comprehensive scenario considers water-saving and energy-saving together) were designed, and the simulation indexes in the three scenarios were refined in order to strengthen the control of water-saving policies, improve the effective use of water, optimize the industrial energy structure, improve the level of energy-saving-related technologies, and advance the urbanization process. The simulation results for Ningbo City from 2010 to 2030 show that the water–energy coupling system is affected by many factors, and the adjustment of a driving factor of any subsystem will have an impact on the water–energy coupling system. There are two driving factors: the first is a constant variable related to water resources, energy, society, and economic, and the second is a variable affected by time. The coupling system is based on the law of real development and is composed of causal and functional relationships between variables. Therefore, within the prediction range of 2030, the driving factors in the coupling system are controllable, and there is no uncontrollable situation. The strengthening of water-saving policies and the improvement of the coefficient of the effective utilization of water will have the optimal saving effects on water resources and energy at both the single and the coupling level; this also demonstrates that the water resource management in Ningbo City plays an extremely important role in the relationship of the water–energy coupling. The results of this study are expected to provide a valuable reference for the management and conservation of water–energy coupling in Ningbo City.

Wei Zhou, Qingjuan Chen, Danxue Luo et al.

To comprehensively assess global sustainable energy consumption from the perspectives of economic development and environmental conservation, we propose a multidimensional structure that includes two-dimensional and three-dimensional networks. Based on the proposed methods, we empirically investigate 35 countries of the International Energy Agency. It is found that: 1) Regarding economic income, Asia ranks first, followed by America, Oceania, Europe and Africa. 2) As for sustainable development, the best-performing region is Asia, followed by Africa and Europe, Oceania and America. 3) The regions with greater development potential in energy consumption are America, Oceania, Africa and Europe, while Asia is less efficient. In consideration of the above findings, we give some recommendations for different regions to improve their energy consumption efficiency, such as countries in Asia can focus on innovative high-tech industries while countries in Europe can enhance economic vitality with market integration.