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This paper presents a method to establish typical operating conditions for train traction systems by combining site-based short trip analysis with nonparametric tests, in order to overcome various obstacles, such as inadequate efficiency testing results based on rated points of train traction systems, which often fail to accurately reflect the actual energy efficiency level of systems during long-distance operation under multiple conditions, and the existing absence of typical operating conditions essential for supporting the evaluation of traction systems' energy efficiency levels and guiding the energy-saving design of products. First, short trips were categorized, screened and randomly combined. Then, the optimal short-trip combination was identified through nonparametric tests. Subsequently, the typical operating conditions were developed, taking the traction system of an electric locomotive model as a case study. Furthermore, the proposed method was verified by analyzing errors in operating characteristic parameters and assessing the similarities in velocity-force (V-F) distribution probability two-dimensional matrix. The verification results revealed a deviation between the constructed typical operating conditions and the characteristic values derived from sampled data at 4.54%, and the consistency in V-F distribution probabilities at 98.06%. These findings indicate that the method proposed in this paper accurately reflects the actual operating characteristics of train traction systems, with the established typical operating conditions closely aligning with the actual operating conditions of train traction systems, underscoring their potential for aiding in energy-saving design and energy efficiency evaluation for train traction systems.

【Objective】This paper discusses full lifecycle energy efficiency of optical communication systems in the purpose of energy conservation and carbon reduction. It aims to establish a universal model for description of energy efficiency, which covers all stages of system lifecycle, and it is not limited to specific technologies or network structures. It also analyzes the key influencing factors for improvement of energy efficiency of optical communication systems.【Methods】This paper explores the useful work and energy consumption of optical communication systems, to establish a universal model for energy efficiency. In the expression of useful work, in addition to the commonly used factor data rate, distance factor is introduced as an important factor. The paper recommends that the value generated by data transmissions which meet specific quality requirements and maintaining network connectivity in specific scenario applications should be considered in the description of the useful efficacy. The description method is named as comprehensive useful efficacy. In the discussion of energy consumption, the system lifecycle is decomposed into four stages: manufacturing, installation and construction, operation and maintenance, and waste recycling. Main influencing factors of energy efficiency improvement are discussed based on the established model.【Results】Main results of the research include: (1) Distance factor can be one of the main factors for evaluating the useful work of a system, and distance factors affect energy consumption at various stages of the system's lifecycle; (2) For new scenarios and applications, setting weights for data transmissions which meet specific quality requirements and assigning values for maintaining connectivities status in description of the system useful work could reflect the value brought by the energy cost of the system to meet the needs of scenario applications; (3) Energy consumption factors of each stage of the life cycle should be considered in evaluation of energy consumption of the full lifecycle, and the energy consumption of each stage should be converted into unit time based on the system operating life for accumulation; (4) Optimized network topology and routing design, reduction of line losses, as well as evolution of optical transmission technology and equipment/facility energy saving technologies, are important means to reduce energy consumptions throughout the entire lifecycle of the system and improve the energy efficiency.【Conclusion】This paper discusses the comprehensive useful work and full life cycle energy consumption of optical communication systems, and establishes a universal model to describe the full life cycle energy efficiency of the system. This model takes distance as an important influencing factor in the expression of the useful efficiency and also energy consumption of the system, which corresponds the value of the optical communication system based on communication distance with the energy consumption in the life-cycle caused by distances. It also suggests considering the value generated by data transmissions which meet specific quality requirements and maintaining network connectivity in the evaluation of the useful efficiency. This model could comprehensively evaluate the energy efficiency of optical communication systems, for improvements of system energy efficiency, and could adapt and promote applications of optical communication systems in new scenarios.

Copyright of Study on Optical Communications / Guangtongxin Yanjiu is the property of Study on Optical Communications Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In addressing the challenge of the multiplicative fading introduced by passive reconfigurable intelligent surface (RIS) in high-speed railway scenarios, an effective solution is the deployment of an active RIS. However, the conventional fully-connected architecture of active RIS, characterized by a multitude of active elements, results in excessive hardware costs and power consumption. Consequently, a sub-connected architecture of active RIS was proposed, with the aim of simultaneously considering the system's energy efficiency and the transmission rate in trainground communication. Initially, a system model for active RIS-assisted multi-user scenarios was established, taking into account the distinctive features of the high-speed railway environment. Subsequently, the problem of maximizing system energy efficiency was formulated by considering constraints on the maximum transmission power of the base station, the transmission power of the active RIS, and the phase-shift matrix of the active RIS. Through the utilization of Lagrange dual transformation and quadratic transformation from fractional programming theory, the non-convex problem was transformed into a convex optimization problem. Finally, an alternating optimization algorithm was proposed for the joint optimization of beamforming and the phase-shift matrix of the active RIS. Simulation results indicate that, compared to traditional passive RIS and fully-connected of active RIS architectures, the proposed solution effectively addresses the multiplicative fading issue. Additionally, the proposed solution achieves higher energy efficiency while meeting user transmission rate requirements [ABSTRACT FROM AUTHOR]

To solve the problems of energy limitation, spectrum shortage, and serious co-frequency interference in the unmanned aerial vehicle (UAV)-assisted D2D (device-to-device) communication network under passive eavesdropping, the concept of the network secrecy energy efficiency was introduced by taking into account the secrecy rate and transmit power constraints of each user. Based on the physical layer secure transmission theory, the joint optimization problem of spectrum multiplexing and power control strategies was investigated to maximize the network secrecy energy efficiency. The problem was a nonlinear nonconvex problem, a resource allocation algorithm combining Dinkelbach's algorithm and the convex approximation algorithm was proposed to transform the nonconvex optimization problem into a geometric planning problem through the convex approximation algorithm and ensure that the original problem converges to the global optimal solution by Dinkelbach's algorithm. Simulation results show that the proposed algorithm can effectively mitigate the co-channel interference, improve the network secrecy energy efficiency, and balance the relationship between the secure communication performance and power consumption of the network. [ABSTRACT FROM AUTHOR]

In the face of the high power consumption issue caused by the dense deployment of base stations in cell-free networks, a wideband cell-free network system with sub-connected active reconfigurable intelligent surface (RIS) was proposed. Firstly, based on the constraints of maximum power consumption at the active RIS, amplification factor, and maximum power consumption at the base station, a joint precoding design problem for the base station and RIS was formulated to maximize the energy efficiency. To solve the non-convex problem, advanced techniques including alternating optimization, block coordinate descent, Lagrange dual reconstruction, and multidimensional complex quadratic transformation were applied to transform the original problem into multiple sub-problems. By iteratively solving each sub-problem, the solutions of the original problem was ultimately obtained. The simulation results validate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Electrochemistry is the property of Journal of Electrochemistry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Clean Coal Technology is the property of Clean Coal Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] Energy efficiency improvement is an effective means to increase the synergy between economic development and energy conservation and emission reduction. In this study, the effects of market integration on regional energy efficiency and mechanisms were examined to provide a theoretical support and policy reference for efficiency improvement of China’s unified large market construction policy. [Methods] The stochastic frontier analysis (SFA) model was used to measure the energy efficiency of 239 prefecture-level cities in China from 2006 to 2019, and the growth of energy efficiency was decomposed into three aspects: technological progress, technical efficiency change, and scale efficiency change; the panel fixed effect and mediation effect models were used to analyze the effect of market integration on regional energy efficiency, heterogeneity, and mechanism. [Results] The study found that: (1) Market integration can effectively promote regional energy efficiency, and the improvement of scale efficiency and technological progress are the key paths of market integration improving energy efficiency. (2) Market integration is more likely to improve energy efficiency in regions with high innovation levels and high population densities, and for regions with weaker innovation bases and lower population densities, the development of market integration can take the lead in improving regional scale efficiency and technological progress. (3) Market integration is more likely to improve regional energy efficiency by promoting the agglomeration of productive services. (4) Market integration can help alleviate the disparity of energy efficiency between regions. [Conclusion] The construction of a large national unified market to promote regional market integration is conducive to the effect of regional scale efficiency and technological progress, which in turn improves regional energy efficiency and promotes effective synergy between economic development and energy conservation and emission reduction.

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An energy efficiency optimization transmission scheme using angular information-based channel state in-formation (AI-CSI) was proposed for indoor communications, which integrated the power line communication (PLC) with radio frequency (RF) wireless communication. Specifically, by considering that the Wi-Fi wireless network and the PLC network were the primary and secondary networks, an optimization problem was established to maximize the total energy efficiency of the secondary network. Then, in order to solve the problem, the beam forming weight vector was obtained by using zero-forcing method based on AI-CSI, and an optimization algorithm joint Dinkelbach with Lagrange multiplier was further presented to achieve the optimal power allocation. Finally, computer simulations were given to verify the effectiveness and superiority of the proposed scheme. Besides, the influence of key parameters such as the number of employed antennas and served users was also analyzed. [ABSTRACT FROM AUTHOR]

Extract residue of coal liquefaction residue (ERCLR) is a solid mixture of high carbon, high ash, high sulfur, and complex composition, mainly including unconverted coal, inorganic minerals, and coal liquefaction catalyst. The effective use of ERCLR, which has high utilization value based on high hydrogen-to-carbon ratio, not only improves the thermal efficiency and economy of coal liquefaction process, but also reduces the emissions of pollutants. The energy efficiency analysis, environmental impact, and economic analysis of three power generation systems were calculated and analyzed by Aspen Plus. The three power generation systems are ERCLR gasification combined cycle power generation system, ERCLR combustion power generation system, and ERCLR pyrolysis combustion power generation system. The results show that the energy efficiency of ERCLR gasification combined cycle power generation system is 47.5%, which is better than that of ERCLR combustion power generation system (43%) and ERCLR pyrolysis combustion power generation system (45.3%). The flue gas emission of ERCLR gasification combined cycle power generation system has lower impact on environment than that of the other two systems. ERCLR gasification combined cycle power generation system provides a lower cost of electricity (0.44 CNY/kWh), compared with ERCLR combustion power generation system (0.48 CNY/kWh) and ERCLR pyrolysis combustion power generation system (0.69 CNY/kWh). Therefore, ERCLR gasification combined cycle power generation system has significant advantages over the other two utilization approaches. For the recovery and utilization of ERCLR, ERCLR gasification combined cycle can be given priority to power generation.

In the case of finite alphabet inputs, information transmission rate limit of orthogonal frequency division multiplexing (OFDM) visible light communications (VLC) and radio frequency (RF) aggregation systems is still unknown. Therefore, the unclosed expression information transmission rate and its lower bound with closed expression of OFDM VLC-RF aggregation system are derived based on mutual imformation function, and the problem of energy efficiency maximization is studied based on the two communication rates. Specifically, the energy efficiency maximization problem satisfying the spectrum efficiency (SE) threshold, total electric power and average optical power constraints is studied. At the same time, the Dinkelbach-type algorithm is used to transform the energy efficiency maximization nonconvex problem into a series of convex sub-problems, and then the interior point algorithm is used to solve it. Simulation results show that when SE threshold increases, energy efficiency first remains constant and then decreases, and energy efficiency based on the lower bound of information transmission rate can be used as a low complexity approximation of energy efficiency based on information transmission rate. The finite alphabet inputs VLC-RF aggregation system studied in this paper provides a new direction for practical communication aggregation system research.

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to promote China′s energy conservation and emission reduction and advance high-quality economic development, this paper analyzed the relationship between green technology innovation and energy efficiency in China′s coastal areas, empirical test the internal transmission mechanism between them through intermediary variables, and put forward countermeasures and suggestions. The results showed that green technology innovation could improve energy efficiency, but there was a threshold effect between them. When the threshold was crossed, the effect of green technology innovation on energy efficiency was weakened. Industrial structure, urbanization level and informatization level were the intermediary transmission factors of green technology innovation to improve energy efficiency. In the future, China should further improve the top-level design of ecological civilization, optimize the industrial structure and layout, reasonably control the scale of cities and towns and population, and drive the development of industrialization with informatization.

5G network is considered as enabler for Smart Grids (SG). However, it is inefficient and costly to travel over large area and penetrate physical blind area in SG. The significant improvement in this work is proposing 5G loRa converged network to offer a seamless, large scale, zero wiring, and real-time IoT monitoring strategy. On the basis of this framework, multiple LoRa Ad-Hoc network can coalesce with the 5G SG network via 5G LoRa intelligent gateway. Experiments and tests in real scenarios demenstrate that the proposed 5G LoRa Ad-Hoc networking enables the achievement of communication blind and wide-area SG IoT monitoring. The collection of information is accurate and the system runs stably. By introducing Charnes-Cooper transform and Lagrange Multiplier iteration algorithm, the resource allocation problem is formulated as a mixed integer relaxation optimization, aiming to maximize the sum energy efficiency of multi-hop LoRa. Simulation results unveil that the optimal number of active LoRa nodes and resource allocation in each cluster exists to maximize the area energy efficiency. Analysis also validates the existing ultimate efficiency of our proposed model, which is 6.2 times higher than that of static benchmark algorithms in terms of energy efficiency and QoS requirements.

The fused filament fabrication 3D printing energy efficiency was predated and optimized based on response surface method and support vector regression model. Firstly, the Taguchi method was used to design the six factor three level orthogonal test, based on the response surface method, three factors that had a significant impact on processing energy efficiency were obtained, namely layer height, printing speed and hot bed temperature. Then, the prediction model of processing energy efficiency was established by support vector regression method, and compared with BP neural network method, the results show that the modeling and prediction performance of support vector regression method Is better. Finally, the optimization model aiming at processing time and energy efficiency was established, and NSGA-II, MOEA/D, SPEA2 and MOPSO were used to solve the model respectively, the Pareto front of the four algorithms was analyzed and compared, the results show that NSGA-II performs best in solving this problem, the optimization results obtained by NSGA-II algorithm were compared with the experimental results, which reflects the effectiveness and rationally of the optimization results of NSGA-II algorithm. [ABSTRACT FROM AUTHOR]

The energy efficiency of wireless networks has gradually become an important indicator for evaluating network performance. It's very important to improve the energy efficiency of the coexisting 4G and 5G networks as there are differences in energy efficiency of them. Firstly, the energy consumption composition of base station was analyzed, energy consumption models for 4G and 5G base stations through measured data were established, and then its energy efficiency was evaluated through simulations. The results show that 4G and 5G have their own optimal energy-efficiency areas separated by the critical point of 500 Mbit/s, above which the 5G energy efficiency is better. When dual networks operate simultaneously under the proposed-solution where only 4G is used when the throughput is less than 500 Mbit/s and only 5G is used otherwise, the power consumption of a single station can be reduced by 53.4% and the energy efficiency can be improved by 116.4%. [ABSTRACT FROM AUTHOR]

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BackgroundThe simulation device is one-third scale of the 10 MW solid-fuel thorium molten-salt reactor (TMSR) and has the rated heat power of 370 kW. Nineteen annular channel heaters with wire coil were designed to heat the simulation device to the desired temperature.PurposeThis study aims to further investigate the effect of outer diameter of heating tube and annular width on the flow and heat transfer characteristics of FLiNaK salt in the annular channel heater.MethodsThe flow and heat transfer characteristics of annular channel heater with wire coil were simulated by using Fluent software. The effects of outer diameter of heating tube on the flow and temperature fields were investigated numerically, so did the effects of annular width on the flow and heat transfer characteristics. The overall performance of annular channel heater was evaluated by the principle of entropy production.ResultsThe simulation results show that the axial velocity, radial velocity and tangential velocity are generated and meanwhile counter-flow is formed on longitudinal section.ConclusionsThe outer diameter of heating tube has no effect on the flow and heat transfer characteristics. The larger the outer diameter of heating tube, the higher the energy efficiency. As the increase of the annular width, the pressure loss, the heat transfer coefficient decreases, and the energy efficiency gradually decreases.

With the development of 5G commercialization, the number of 5G wireless base station sites has increased sharply, 5G core networks need to be deployed in regions/provinces/cities data centers, as well as the data centers were developing on a larger scale, the problem of energy consumption was becoming increasingly prominent. Based on the main proportion of energy consumption in the whole network, the energy efficiency evaluation methods of sG access network, core network and data center was investigated. The AI-enabled energy-saving technology of base stations and pilot application scheme, 5G core network energy-saving methods by using AI, as well as the AI-enabled energy-saving technology of data centers and pilot application scheme were introduced, and the challenges and future research directions of energy-saving technology were finally discussed. The summary and prospect on the energy-saving technology of the overall communication system, will help to improve the understanding of energy efficiency and green network development. [ABSTRACT FROM AUTHOR]

Currently, the utilization efficiency of energy still remains at a low level, although the depletion of fossil fuel is appoaching. Therefore, it is of great significance to develop new materials and technologies for energy-saving and environment protection. Phase-change materials (PCM), which can absorb or release heat through inversible phase change, are very promising in the fields of heat storage and thermal management. In this paper, the characteristics and classification of PCM were introduced briefly in the first section, and then the application and development status of PCM were reviewed and analyzed detailedly. In the third part, the main problems of PCM were pointed out, and the related research work and recent research progress were analyzed and discussed. Finally, it was pointed out that optimizing material properties through new functional composite technology, designing new material system, expanding new application fields are the main development directions of phase change energy storage materials.

With the popularity of large-scale MIMO and Internet of Things, energy efficiency(EE) optimization issues will be the challenges of the future development of 5G, in which multiple users reuse in the same sub channel shows more attractive. Assuming that the conditions of the channel state information are fully understood, the base station allocates the machine equipment with the largest allocation factor to the user equipment according to the maximum proportion allocation principle, in the uplink, a bilateral matching algorithm of one sub-channel and user equipment is adopted, and the EE is maximized through the power control and time scheduling based on NOMA. The simulation result shows that the energy consumption of the proposed optimization scheme is reduced by more than 6% compared with the existing schemes.

In order to guide the design,type selection and operation of variable speed permanent magnetic coupler for mine,finite element method is used to simulate electromagnetic field of the coupler. The influence of three key factors air-gap thickness,conductor plate conductivity and conductor plate thickness on three important performance indexes the maximum transmission torque,the maximum adjustable speed and the power loss were analysed. then the analysis results were applied to load matching.The analysis results obtained the correlation between three factors and three performance indexes. For constant torque,permanent magnet coupling has a maximum speed range of 13%; but it has no energy-saving effect,and for quadratic law load,it could reduce 13% of flow and has up to 34% energy savings.

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Telecommunications Science is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper theoretically analyzed energy transfer progress of robot, obtained efficiency equation of every link of energy transfer progress , and established comprehensive energy efficiency model of robot. It also got the relationship among the efficiency, current and battery capacity through Matlab simulation, drew following conclusions: battery capacity has little impact on energy efficiency of robots, output current determines energy efficiency of the robot, when the output current is 20 A, the robot has maximum energy efficiency. The conclusion could provide the theoretical basis for establishment of energy consumption model of robot, battery capacity determination and power management.