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Aiming at the situation of imperfect spectrum sensing of cognitive radio in actual cognitive ultra-dense network sce- narios, this paper proposed a resource allocation scheme based on imperfect spectrum sensing. The target was to maximize the energy efficiency of secondary network in cognitive ultra-dense network with imperfect spectrum sensing while taking into ac- count cross-tier/co-tier interference constraints and ensuring users quality of service. And this paper constructed the energy efficiency optimization problem based on the network model, which was a mixed integer non-convex programming problem, then transformed it into an equivalent convex optimization problem by the time-sharing relaxation method and Dinkelbach me- thod, and finally used the Lagrangian dual method to get its optimal solution, thereby obtained the sub-channel and power allo- cation strategy for optimal energy efficiency. Based on this, this paper proposed an iterative sub-channel and power allocation algorithm. In order to trade off the computational complexity, this paper also proposed a practical sub-channel and power allo- cation algorithm. Simulation results show that the proposed algorithms effectively improve energy efficiency. [ABSTRACT FROM AUTHOR]

Addressing the optimization problem during the simultaneous energy and information transmission stage in the simultaneous wireless information and power transfer (SWIPT), an optimal energy efficiency strategy based on mmWave cooperative communication small cell is proposed to maximize the link energy efficiency. This strategy, under the joint constraints of minimum link transmission rate and minimum collected energy, employs a power splitting mode at the receding end of energy-constrained user devices. By optimizing transmit power control and power splitting factors, it aims to maximize the systems link energy efficiency. Recognizing the original problem as a nonconvex fractional programming problem with NP-hard characteristics, the Dinkelbach method is utilized to transform the objective function into a convex optimization problem that is easier to solve. An iterative algorithm is designed to find the optimal solution through cross iterations. Simulation results demonstrate that the proposed strategy outperforms traditional power control methods and maximum transmit power approaches in optimizing system energy efficiency. [ABSTRACT FROM AUTHOR]

In order to optimize the energy efficiency and spectral efficiency of decoded-and-forwarded full-duplex relay network in imperfect channel state information, this paper proposed an energy efficiency and spectral efficiency balancing strategy based on this network model. It could replace the non-convex multi-objective optimization problem to a convex single-objective optimization problem by constructing a compromise optimization function of energy efficiency and spectral efficiency. It used derivation method and Lagrange multiplier method to solve the optimal relay transmission power under different compromise factors. The simulation results show that changing the compromise factor can change the energy efficiency and spectral effectiveness of the system and obtain the performance tradeoff of energy efficiency and spectrum effectiveness. [ABSTRACT FROM AUTHOR]

Agricultural machinery is ever-increasingly either displacing or augmenting human labor with the development of the economy and technology. Among them, fuel efficiency has a significant impact on energy conservation and emission reduction, indicating high economic and social significance. Particularly, a tractor is one of the most typical agricultural machinery. In this study, the overall energy efficiency of tractors was evaluated under actual operating conditions. The performance of tractors was also measured comprehensively. The actual energy efficiency of tractors was clearly defined and calculated as well. The common operating points of tractor engines were extracted by K-means clustering and pairwise comparison matrix, according to the shortest distance partition. The energy efficiency of 186 162 kW tractors was analyzed to propose the classification standard using tractor energy efficiency. Energy efficiency limits and energy efficiency ratio limits were determined at all levels. The average energy efficiency was compared using different operating links. The results showed that there was a significant difference in the distribution and weight between the actual eight operating points and the ISO steady-state eight operating points. The main reason was that the ISO steady-state eight operating point was targeted at nonroad diesel engines, covering a wide range of engine models, power, and applications. However, the actual eight operating points were more specific, and refined for the actual operating conditions of multiple 162 kW tractor engines. The error range of tractor energy efficiency was −0.483-0.487 (kW·h)/kg using two datasets of working conditions. Therefore, the energy efficiency calculation was necessary and meaningful using the actual eight working conditions. In addition, there was a significant difference in the tractor energy efficiency using actual operating conditions, where 50% of tractor energy efficiency values were distributed in the range of 3.20 to 3.65 (kW·h)/kg, with an average value of 3.42 (kW·h)/kg. This difference was attributed to the driving habits of agricultural machinery operators, the tractor maintenance and repair levels, as well as the tractor age, resulting in the varying degrees of reduction in engine performance indicators. Then, the grading was constructed using the tractor energy efficiency, where 3.07 (kW·h)/kg was determined as the qualification limit of actual energy efficiency in the tractor. The limit values were also determined for the tractor energy efficiency ratio for levels 1-4. As such, the classification of energy efficiency levels was achieved for tractors. There was a significant variation in the average energy efficiency at different operation stages of each tractor. The rotary tillage mode presented the highest value of average energy efficiency, whereas, the walking mode was the lowest. The trend was attributed to the different engine loads of tractors at different operating stages. Therefore, there was great potential for the real-world energy efficiency performance of tractors from a user perspective. The actual operating performance of tractors was explored to establish an evaluation system applicable to the energy efficiency performance of tractors in the real world. The findings can provide the basic data for energy-saving and emission reduction in tractor engines. A strong reference can be also offered to assess the energy efficiency of agricultural machinery on application subsidy suitable for the level of green operation. [ABSTRACT FROM AUTHOR]

Exploring the green economic effects of digital economy development from the dual perspective of reducing urban pollution emissions and improving urban energy efficiency is in line with the requirements of the times for a Chinese path to modernization. This study analyzed the spatial and temporal patterns of digital economy development in China based on panel data from 280 Chinese cities at the prefecture level and above from 2011 to 2019 using ArcGIS spatial analysis and adopted the fixed effects model, the difference-indifferences model, and the spatial Durbin model to test the ‘emission reduction’ and ‘efficiency enhancement’ effects of digital economy development. The results showed that: ① China’ s digital economy development as a whole showed an incremental trend, and the regional development gap was narrowing. In terms of spatial evolution pattern, the development pattern of advance zones evolved from sporadic distribution to multi-point coverage, and the number of promotion areas distributed around the advance areas gradually increased, forming a group development pattern with the advance areas. ② The development of the digital economy was conducive to reducing about 4% of urban pollution emissions and improving about 9% of urban energy efficiency, and this conclusion still held after a series of robustness tests and endogeneity discussions. ③ The impact of digital economy development on ‘emission reduction’ and ‘efficiency enhancement’ differed by geographical location, administrative level, and resource endowment. Among them, the digital economy development in the eastern region only enhanced efficiency but did not reduce emissions, while the digital economy development in non-eastern regions, central cities, and non-resource-based cities both reduced emissions and enhanced efficiency. ④ Industrial structure upgrading was the intermediary mechanism for ‘emission reduction’ and ‘efficiency enhancement’ of digital economy development, while human capital was only the intermediary mechanism for ‘efficiency enhancement’ of digital economy development. ⑤ The digital economy development was conducive to ‘emission reduction’ and ‘efficiency enhancement’ in a region, but through the spatial spillover effect on neighboring regions, only ‘efficiency enhancement,’ not ‘emission reduction’ was achieved. This study suggests that we should continue to strengthen the foundation of digital economy development. While being alert to the development gap between regions, we should try to improve the data element resource system, focus on cultivating versatile talents, and promote the transformation and upgrading of traditional industries, so as to help the region form a synergy for digital economy development and achieve the ‘winwin’ goal of reducing pollution emissions and improving energy efficiency for the whole society. [ABSTRACT FROM AUTHOR]

In MEC combining IRS and resource allocation strategies to improve system energy efficiency is a current hot topic of research at home and abroad. This paper aimed to maximize energy efficiency in IRS-assisted MEC system through joint optimization of the computing frequency at users, transmit power and time, and the IRS discrete phase-shift based on the transmission mode of hybrid non-orthogonal multiple access. Since the optimization process involved non-convex fractional programming problems that are difficult to solve, this paper proposed a Dinkelbach-SCA algorithm with two iterative-steps. Firstly, this paper converted the initial problem into a tractable form via Dinkelbach' s method, optimization of IRS discrete phase shift by separating variables. Then, by introducing auxiliary variables, and leveraging successive convex approximation, the paper decoupled the relationship between transmit power and time while converted the non-convex problem to a convex one. Hence, the paper could obtain optimal solution. The simulation results show that the energy efficiency of the proposed system scheme is better than other comparison ones, and the energy efficiency of the system increases with the decrease of the minimum computational data amount of user 2. [ABSTRACT FROM AUTHOR]

The energy-consuming right trading system is a market-oriented environmental regulation policy based on source control in China, the implementation of which aims to help the realization of the goal of controlling total energy consumption and energy intensity and to promote green development. Based on the panel data of prefecture-level cities from 2012 to 2019, this article theoretically analyzed the mechanism of the action of the energy-consuming right trading system; applied the multi-period PSM-DID method to empirically test whether the energy-consuming right trading system had achieved win-win development for both the environment and the economy; and tested the robustness of the findings by replacing variable settings, adding control variables, and applying placebo tests. In addition, the short-term and long-term impact paths of the environmental and economic effects of the energy-consuming right trading system are theoretically analyzed and empirically tested respectively. The findings were as follows: (1) The implementation of the energy-consuming right trading system effectively reduced the total emission and emission intensity of energy pollutants and realized positive benefit for the environment. Besides, the reduction in emission intensity was more significant. (2) The energy-consuming right trading system not only increased the quantity of economic development, but also pulled up the economic growth rate, thus realizing a positive benefit to the economy. (3) The results of the dynamic effect analysis showed that the energy-consuming right trading system did not have a persistent effect on the total amount and intensity of pollution emissions. But it had a more significant and persistent effect on the rate and level of economic development. (4) Since the energy-consuming right trading system was in the early pilot stage, it mainly achieved environmental and economic dividends through the short-term path of improving energy efficiency and not the long-term path of industrial structure upgrading or energy structure adjustment. Based on this, we should further build and improve the energy-consuming right trading market and improve the design of the system to ensure standardization, convenience, and transparency during the operation and enhance the degree of marketization. It is also of great importance to accelerate the development of new energy, new technologies, and new industries to promote green transformation and decarbonization in the energy industry. Furthermore, we should build a comprehensive and coordinated environmental policy system by promoting the coordinated implementation of the energy-consuming right trading system with other environmental regulation policies based on emission control, realizing the benefits of ' 1 + 1 >2.' [ABSTRACT FROM AUTHOR]

This paper proposed a power and bandwidth allocation algorithm that maximized energy efficiency with backhaul capacity constraints for heterogeneous cellular networks using non-orthogonal multiple access (NOMA) technology. Firstly, considering the small cell transmit power constraints, small cell rate constraints and backhaul link capacity constraints, it constructed a power and bandwidth allocation model. Then,for power allocation, it used the difference of convex( DC) programming and the quasi-concavity of the function to transform the original problem into an equivalent convex problem, and used the convex difference iteration method and the dichotomy to find the global optimal solution. For the backhaul link bandwidth allocation, it transformed into a feasibility problem and gave an analytical solution. The simulation results show that the energy efficiency of the proposed scheme is higher than that of the existing schemes in the same scenario. [ABSTRACT FROM AUTHOR]

Objective As the core part of gas storage, the ground system of gas storage has unstable operation conditions and high energy consumption due to the dual influence of gas injection and production. The aim of this study was to tap energy-saving potential points and solve the problems of imperfect energy efficiency evaluation system method as well as the unclear evaluation boundary of surface process system of gas storage. Methods Combined with the current relevant standards, the Delphi method is used to establish the energy efficiency evaluation index system of gas storage ground process system covering 3 levels and 15 indices, and a set of energy efficiency evaluation method of gas storage ground process system is proposed based on the combination of analytic hierarchy process (AHP) and fuzzy function method. Results The demonstration application shows that the energy efficiency evaluation score of the surface process system of gas storage under normal and abnormal working conditions is 74. 68 and 48.68, respectively. Conclusions The established energy efficiency evaluation index system and evaluation method can reasonably reflect the energy efficiency level, adaptability and existing problems of the surface process system of gas storage under normal and abnormal working conditions. The adoption of this evaluation method provides a basis and reference for the energy-saving work of surface process system of gas storage, and is of great significance to improve the energy efficiency level of oil and gas field enterprises and natural gas pipeline network companies. [ABSTRACT FROM AUTHOR]

As the one of typical volatile organic compounds (VOCs), the formaldehyde was the main indoor air pollutant. ln recent years, the application of atmospheric pressure discharge plasma in the domain of environmental protection has become a research hotspot. ln this paper, a multi-needle-to-plate corona discharge reactor with an S-shaped gas channel was designed and manufactured. The corona was generated by a high-voltage DC power supply, and the active components produced by air ionization were used to degrade formaldehyde gas. The results showed that the degradation rate of formaldehyde increases with the applied voltage increasing. When the applied voltage was 18.5 kV, the energy efficiency of formaldehyde degradation reaches a maximum. With the increase of the gas flow rate, the degradation rate of formaldehyde decreases, and the energy efficiency reaches the largest value when the gas flow rate was 30 L/min. With the increase of the initial concentration of formaldehyde, the degradation rate decreases. Among the components produced by corona discharge, there was a close correspondence between ozone and formaldehyde. The variation of ozone concentration generated by discharge was similar to that of formaldehyde concentration under the two conditions of with or without formaldehyde. The design of an S-shaped discharge channel makes the plasma degrade formaldehyde more efficiently, and it has practical significance in the application of large flow treatment of formaldehyde gas. [ABSTRACT FROM AUTHOR]

Small molecular organic acids such as acetic acid are often produced in the oxidation treatment of organic wastewater, the acetic acid is difficult to be mineralized due to the presence of α-position methyl group on the carboxyl group. In this study, three catalysts are prepared from MnO2 as the active component and γ-Al2O3 with different morphologies(powder, honeycomb and sphere)as the support to investigate the effect of support morphology on MnO2 catalytic ozonation mineralization of acetic acid via ozone gas bubbling at room temperature. The results show that using the MnO2 catalysts with powder, honeycomb, and spherical γ-Al2O3 supports, the acetic acid mineralization is 89.0%, 54.6%, 38.7%, and the energy efficiencies are 13.7, 11.2, 7.0 g/(kW·h), respectively, indicating that the MnO2 catalyst with the powder γ-Al2O3 support is the best catalyst for acetic acid mineralization. [ABSTRACT FROM AUTHOR]

In forest and crop monitoring operations, crop environmental information can be collected by self-organizing WSN formed by spreading wireless sensor nodes. When the UAV is applied to the clustered WSN as the mobile sink node for data collection, the UAV needs to forward not only the information of each cluster head node, but also the important information detected by its own sensor. In order to ensure the timely forwarding of UAV sensor detection information, further reduce the energy consumption of cluster head node and prolong the life of WSN network, this paper proposed an asynchronous data forwarding polling control system with priority, and used Markov chain and probability generating function to model and analyze the system performance. Using FPGA with asynchronous reading and writing FIFO function as the main control device, it designed the hardware circuit structure of the polling system based on FPGA, which verified the feasibility and high efficiency of the polling control system. Experimental results show that the proposed scheme can ensure timely transmission of important data by UAV, shorten service delay, improve WSN energy efficiency and optimize system performance . [ABSTRACT FROM AUTHOR]

Marginal lands can greatly contribute to fully meeting the ever-increasing demands for cultivated resources in recent years. In general, the available marginal land refers to the new reclamation lands that converted from grassland, wetland or other lands in the past 25 years. Among them, there are serious land desertification and low productivity in Inner Mongolia of northwestern China, where the marginal land is widely distributed so far. Alternatively, Cyperus esculentus L. has been one of the most important crops to ensure the safety of grain and oil in China, due mainly to the high yield and oil content. Therefore, it is a new idea to promote the cultivation of Cyperus esculentus L. on a large number of marginal lands under a rapid development of mechanized agriculture. In this study, a multi-factor comprehensive evaluation was made to determine the cultivation and production potential of Cyperus esculentus L. in the marginal land of Inner Mongolia, further to predict the energy and economic benefits from the new oil crop. The results show that there was a total of 125 000 km² of marginal land in the study area, of which the area of first-class marginal land was 26 000 km², mainly distributed in the central and eastern Bayannur, Baotou, Xilinhot, and Tongliao counties. The types of land cover were the sparse vegetation, farmland and mixed vegetation. The area of second-class marginal land was 64 000 km², particularly distributed in Huolin Gol, and Wuhai City, where there were the vegetation-based farmland and vegetation mixed areas. The area of third-class marginal land was 35 000 km², mainly distributed in the desert edge areas of the western Alxa League. It was difficult to reclaim in some complex restricted areas with harsh climate conditions, due to the low rainfall and transportation. As such, approximately 15.9 million tons of edible oil was produced per year, when planting the Cyperus esculentus L. on these marginal lands. Otherwise, 1.87×1012 MJ of biomass energy was obtained, corresponding to the 44.7 million tons of fuel oil. On the whole, Cyperus esculentus L. presented great potential in the production of edible oil and biodiesel. Correspondingly, the marginal land can be widely expected to alleviate the shortage of edible oil, as well as the energy crisis in the realization of carbon neutral goals. The marginal land can also be fully utilized to alleviate the increasingly tense human-land contradiction for a higher land productivity. Since the industrial chain of Cyperus esculentus L. has not yet been fully mature, the accuracy of the estimation can increase with the promotion of plantation and industry, when evaluating the potential of planting, oil yield, and biomass energy production on marginal lands. The finding can also provide a scientific data support to the marginal land use, as well as the cultivation and promotion of Cyperus esculentus L. in the sandy areas of northwestern China, so as to alleviate the shortages of regional grain, oil and energy resources. [ABSTRACT FROM AUTHOR]

Millimeter wave（mmWave） massive MIMO system generally adopts hybrid precoding combining digital and analog precoder as an alternative of full digital precoding to reduce RF chain and energy consumption. However, the singular value decomposition（SVD） could bring high complexity in calculating the optimal unconstrained hybrid precoder. Therefore, this paper proposed a low complexity hybrid precoding algorithm based on projection approximate subspace tracking（PAST). When calculating the optimal unconstrained hybrid precoder of each sub-rate, the proposed algorithm used the PAST algorithm to estimate the required major column vectors of the right singular matrix, thus avoiding the high complexity of SVD process. Simulation results demonstrate that the proposed algorithm approaches the performance of the SVD-based hybrid precoding in terms of spectral efficiency for full-connected, hybrid-connected and sub-connected system structure, and as the increase of the number of transmitting antennas, the complexity and time consumption of the proposed algorithm are significantly lower than that of SVD-based hybrid precoding. Meanwhile, the proposed algorithm has smaller bit error rate（BER） and better reliability. [ABSTRACT FROM AUTHOR]

In order to improve the rationality of the actual base station deployment, for the base station deployment of the heterogeneous cellular network（HetNet), this paper considered the repulsion among MBSs, and the repulsion between MBS and PBS. First, this paper used the approximate SIR analysis method of cellular network to derive the coverage probability of the two-tier non-Poisson network. Next, it analyzed the network energy efficiency and derived the throughput and total network energy efficiency. Finally, it proposed an energy efficiency optimization algorithm for the transmission power, which maximized the network energy efficiency by optimizing the transmission power of the PBS. The simulation results show that, the coverage pro-bability of proposed model is better than that of the two-tier HPPP model, and the energy efficiency optimization algorithm can increase the system energy efficiency by about 30%.In actual deployment, people should set the appropriate value of transmit power for PBSs, and control the distance among base stations. [ABSTRACT FROM AUTHOR]

To improve the throughput and energy efficiency of wireless sensor network ( WSN) in intelligent transportation system (ITS), this paper proposed a cooperative multiple input multiple output automatic repeat request protocol with spatial modulation( CMIMO-SM-ARQ). It considered a four-node WSN with dual sending nodes and dual receiving nodes, in which both receiving nodes could act as relays to each other to assist the sender transmitting data, to reduce the probability of system outage. The paper established the discrete time Markov chain ( DTMC) model of CMIMO-SM-ARQ protocol with 3L + 1 states and gave the state space. Based on the outage probability of WSN and the one-step state transition probability matrix, it derived the analytical expressions of throughput, energy efficiency and delay of CMIMO-SM-ARQ protocol. Numerical simulation results show that the outage probability and energy efficiency of the proposed protocol are better than the single input single output automatic repeat request ( SISO-ARQ) protocol, and the CMIMO-SM-ARQ protocol has a higher throughput and lower delay when transmitting information at medium and long distances( over 67 m). [ABSTRACT FROM AUTHOR]

With the continuous expansion of the number and scale of data centers, energy consumption has become a key issue that restricts the cost and reliability of data centers. Moreover, with the iterative updates of the hardware after the data center is put into operation, the heterogeneity of the data center server has further increased, and its energy efficiency has also under gone major changes compared with the initial design and construction. Therefore, according to the structure and hard ware configuration of the data center server, the dynamic energy efficiency simulation and analysis of the entire data center will help to grasp the energy efficiency status of the data center in real time, carry out energy efficiency aware load scheduling, and provide the possibility of energy efficiency optimization. Based on the SPECpower test results of enterprise-level servers, this article first analyzes the energy efficiency development trends and influencing factors of servers in recent years. Secondly, based on the genetic algorithm, the energy efficiency optimization of the data center is simulated, and a prototype system of the energy efficiency simulator of the data center is designed. The simulator can dynamically simulate and adjust the operating status of data center servers according to power supply limits, load conditions, throughput indicators, etc., and simulate the energy efficiency of data center s of different sizes and types of servers. The proposed data center energy efficiency simulation algorithm based on genetic algorithm obtains smaller errors and shorter simulation calculation time in the energy minimization problem. [ABSTRACT FROM AUTHOR]

Abstract：Existing studies have analyzed the impact of industrial transfer demonstration zones from the aspects of economic development, industrial upgrading, urbanization and pollution, while few literature has dealt with the impact of the industrial transfer demonstration zone policy on energy efficiency. This paper focused on the impact of industrial transfer demonstration zones on energy efficiency and their mechanism. Based on the panel data of 281 prefecture level cities in China from 2004 to 2017 and the framework of Schumpeter’s innovation theory, this paper used the difference-in-differences method to study the impact of industrial transfer demonstration zone construction on total factor energy efficiency. The results showed that:（1） The industrial transfer demonstration zones could improve the energy efficiency by about 12%, and the conclusion was still robust after a series of robustness tests.（2） Mechanism analysis showed that, as an innovative mode of urban industrial development, industrial transfer demonstration zones improved energy efficiency mainly through technical effect and structural effect.（3） The heterogeneity analysis of city scale showed that the larger the city scale, the stronger the role of demonstration zones in the improvement of energy efficiency; the heterogeneity of city features showed that the higher the level of urban informatization and foreign investment, the stronger the role of demonstration zones in the improvement of energy efficiency.（4） Based on the analysis of the development characteristics of the industrial transfer demonstration zones, the results showed that the larger the scale of industrial transfer demonstration zones, the stronger the role of industrial transfer demonstration zones in the improvement of energy efficiency. This paper has important reference value and significance for China to further adjust and implement the industrial transfer policy, balance the domestic regional economic development, and promote the improvement of total factor energy efficiency in the central and western cities. The direct policy implication suggests that we should strengthen the implementation and incentive, reduce the regional development differences, optimize the upgrading of industrial structure, and promote the economic development. We should also pay attention to the role of technological innovation, develop and improve the intelligent detection system, enhance the role of clean energy alternatives, improve the efficiency of resource utilization, build information platforms, and improve the infrastructure construction of the demonstration zones. Furthermore, the level of opening up should be updated and the candidate enterprises and foreign investment should be strictly screened. [ABSTRACT FROM AUTHOR]

To overcome the serve energy consumption problem in indoor wireless networks, a deep Q-Learning based transmit power allocation algorithm for home base station is proposed. Firstly, a deep learning network (DLN) is built to optimize the energy efficiency of indoor wireless networks. Then, the energy consumption rating is regarded as the rewards, the batch gradient descent method is used to continuously train the weights of DLN. Finally, the simulation results show that the proposed algorithm can dynamically adjust the transmit power, and is significantly superior to Q-Learning and water-filling algorithms in terms of convergence speed and EC optimization, which can effectively reduce the energy consumption of indoor wireless networks. [ABSTRACT FROM AUTHOR]

Energy efficiency optimization is a research hot spot in the field of S G communications. First, this paper established an energy efficiency optimization model with regard to transmit power, pilot sequence length, and number of base station ( BS) antennas under user QoS requirements and the system' s tolerable channel effective noise in a single-cell multi-user uplink massive MIMO system. Then, different from the traditional iterative algorithm for solving the optimal number of BS antennas, the method used a closed-form expression to solve the optimal number of BS antennas using Lambert W function. Finally,according to the fractional programming, this paper proposed an iterative optimization algorithm to jointly optimize the system pilot sequence length, transmit power, and number of BS antennas. The simulation results show that the energy efficiency of the algorithm is 11. 2 % higher than that of the existing algorithm, indicating that the algorithm can effectively improve the system performance. [ABSTRACT FROM AUTHOR]

There is a significant imbalance in the distribution of energy in China. With the continuous exploitation of energy and the adjustment of the national energy layout, energy production capacity is rapidly showing a trend of spatial accumulation. In the context of dramatic changes in the world energy landscape and global environment deterioration, studying the mechanism and effects of spatial agglomeration of energy production capacity on regional energy efficiency can provide useful guidance for China in formulating relevant energy policies and energy strategies. Using the provincial panel data from 2000 to 2017, this paper constructed an energy spatial agglomeration measurement model, a total factor energy efficiency measurement model, a model of the influence of spatial agglomeration of energy production capacity on regional energy efficiency, and a mediating effect test model to study the mechanism and effect of spatial agglomeration of energy production capacity on regional energy efficiency. The results showed that;① The spatial agglomeration of energy in China's eastern, central and western regions was showing a trend of convergence. Among them, the spatial concentration of energy in the eastern region gradually decreased, that in the western region gradually increased, and that in the central region first increased and then decreased.② China's regional energy efficiency was significantly different, and the overall performance was: energy efficiency in the eastern region > that in the central region > that in the western region. (3) The impact of spatial agglomeration of energy production capacity on regional energy efficiency had regional heterogeneity. From a national perspective, spatial agglomeration of energy production capacity had a significantly positive effect on energy efficiency; from a regional perspective, the spatial agglomeration of energy production capacity in the eastern region promoted energy efficiency, while having a restraining effect on the central and western regions.④ Energy structure and technological innovation were two important factors through which the spatial agglomeration of energy production capacity affected energy efficiency. Based on the above research conclusions, policy recommendations have been put forward to implement the coal development strategy of 'restricting the eastern region, controlling the central region, and developing the western region', accelerate the development of new energy and expand the scope of the carbon trading mechanism in the central and western regions to optimize the energy consumption structure, vigorously promote policy recommendations for energy-saving technological innovation and the development of energy-saving industries and increase energy efficiency assessment in the central and western regions. [ABSTRACT FROM AUTHOR]

Mobile cloud computing can use the computation offloading to improve the energy efficiency of mobile devices and the execution delay of applications. However, in the face of the multiple service selection from cloud, the computation offloading d ecision is a NP problem. In order to address this problem, this paper designed a genetic algorithm to find the best application p artitioning decision solution for computation offloading. In genetic population initialization, this algorithm combined of predefined and random chromosomes to initialize the population, which could reduce the generation of the inefficient chromosomes . At the same time, the algorithm designed a specific fitness function based on Hamming distance function for the predefined reserved population, which could better measure the difference between chromosomes. The population crossover used respectively the inbreeding and c rossbreeding to enrich individual species. The algorithm used the modified genetic operations to reduce the ineffective solutions and obtain the best feas ible solution in a reasonable time. It evaluated the efficiency of the proposed algorithm using graphs of real mobile applications in simulation experime nts. The evaluated conclusions denote that this designed algorithm has a better performance than the comparision algorithms on the application execution energy, the execution time and the overall weight cost. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) have important applications in many fields such as medical treatment and industry. WSNs typically consists of a large number of sensor nodes that rely on limited power supply in many applications. Therefore, improving the energy efficiency of WSNs has become an important research topic. As a basic service in WSNs, network flooding has the advantage that information can be distributed quickly and reliably in the whole network. However, due to a large number of redundant transmissions in the network, the energy efficiency of network flooding is low. We use the connected domination set (CDS) to improve the energy efficiency of network flooding by reducing the number of transmissions. A flooding protocol based on CDS, named CONE, is proposed. CONE inhibits nodes that are not in the CDS from rebroadcasting packets during the flooding process. In the simulation experiments, CONE performance is evaluated by comparing it with the baseline protocol. The experimental results show that the method improves the end-to-end reliability and reduces the duty ratio of network flooding. It is able to effectively decrease the average energy consumption. [ABSTRACT FROM AUTHOR]

In order to explore the spatial spillover effect and regional differences of direct rebound effect， the measurement model of direct rebound effect has been improved based on the spatial measurement method， and the empirical analysis has been conducted on the basis of spatial panel data of Chinese urban residents’ electricity consumption. It is found that there is a significant spatial spillover effect in the direct rebound effect. Ignoring the spatial spillover effect will confuse the impact of energy efficiency improvement in urban residents’ power consumption on local and neighboring regions. Owing to the difference between the local and global spillover effect， the government should pay much attention to the scope of the energy efficiency policy to reach its full potential. The direct rebound effect and spatial spillover effect of urban residents’ electricity have few differences in the eastern， central and western regions， and they are steady at the regional level. [ABSTRACT FROM AUTHOR]

During the storage of fruits and vegetables, the uniformity of air distribution inside the cold storage store is crucial to affect both the storage quality of fruits or vegetables and energy efficiency of supply air. In the traditional cooling fan direct blowing air supply mode, some local air velocities and temperatures are easily to be larger than those required for cargo area, which would greatly reduce the uniformity of air distribution and the storage quality of fruits and vegetables. Therefore, the reasonable airflow organization is critical to the air distribution of the cold storage and must be carefully considered. In order to improve the uniformity of indoor air distribution, the study introduced the vertical wall attached ventilation which originated applied for indoor climate control of public buildings. To investigate the flow characteristics of the vertical wall attached ventilation, a three-dimensional SST k-ω solution model was established to study the distribution characteristics of the flow field and the cooling effect of the stored cargo. According to the practical array of the stored apples, the cargo area was regarded briefly as porous medium zone. In order to ensure the accuracy of the numerical calculation and the rationality of the mathematical model, grid independence verification and experimental verification were carried out. The accuracy of numerical calculation was studied by comparison with some accepted correlations and the rationality of the mathematical model was proved. The velocity distribution and temperature distribution of typical sections were monitored to illustrate the air flow pattern and temperature distribution characteristics under the vertical wall attached ventilation mode. Meanwhile, compared with the traditional air supply by cooling fan for direct blowing, it was clarified that the vertical wall attached ventilation could form a more uniformly temperature distribution and velocity distribution on the monitoring section and monitoring line. However, the air distribution of monitoring section and monitoring line could not fully reflect the overall temperature and velocity distribution inside the cold storage. Furthermore, the air distribution evaluation index was introduced and calculated in order to fully understand the temperature distribution characteristics of the studied cold storage room. First of all, in order to reflect the uniformity of air distribution, the non-uniformity coefficient of temperature and non-uniformity of velocity were introduced. According to the temperature and velocity values of 40 measuring points in each stack, the velocity non-uniformity coefficient and temperature non-uniformity coefficient were calculated under two air distribution modes. It was manifested that the vertical wall attached ventilation enabled non-uniformity coefficient of temperature and non-uniformity of velocity to decrease by 31% and 47%, respectively at the same air supply flow rate and temperature. Secondly, to evaluate the energy utilization of the air supply, the energy utilization efficiency of the two modes was calculated from monitoring air supply temperature, air return temperature and average temperature in the cargo area. It was indicated that the vertical wall attached ventilation made the energy utilization increase by 19% due to the more sufficient heat exchange between the air and cargo. Since the vertical wall attached ventilation can form a more uniform air distribution under a higher energy utilization rate, it can effectively improve indoor air distribution characteristics and well meet the storage requirements of fruits and vegetables [ABSTRACT FROM AUTHOR]

Due to the increasing demand for high performance computing in scientific research and commercial applications, the performance and system scale of high performance computing are developing rapidly. However, the rapid increase in power consumption severely limits the design and use of high-performance computing (HPC) systems, which makes low-power technologies become the key technology in the HPC field. As the core component of the whole system and based on limited system resources, the job scheduling system distributes job resources to the applications submitted by the users. Its energy efficiency plays an important role in the control and regulation of the energy consumption of the whole HPC system. We first introduce the main energy efficiency techniques and common job scheduling strategies, then analyze the energy efficiency of current HPC job scheduling, and discuss the challenges it faces and future development directions. [ABSTRACT FROM AUTHOR]

This paper presented a collaborative optimization scheme based on the utility function maximization model for user association and power control to increase energy efficiency in heterogeneous cellular networks, this scheme expressed as a nonlinear and mixed integer problem. In order to found the optimal solution of this problem, it designed an iterative algorithm, first, it transformed the original problem into a polynomial problem with parameters, then, found the best energy efficiency factor by Dinkelbach method in outer layer, next, it obtained the optimal user association matrix and transmission power respectively in inner layer. At last, experimental results show that the proposed scheme has better performance in terms of energy efficiency and load balancing than the user association strategy at fixed power. [ABSTRACT FROM AUTHOR]

In view of the current D2 D multicast content delivery mechanism has a large amount of transmission redundancy, lead to low energy efficiency and low spectrum efficiency. This paper proposed a novel demand-aware D2 D video distribution mechanism. By predicting users’ video service requests, it pushed the video to potential service users while distributing video for service request users. Firstly, it estimated the willingness of potential service users to accept video push based on the users’ interests, the popularity of the video and the residual-energy of the users’ devices. Secondly, it proposed the utility measure of video distribution service to measure the value of video distribution service, and modeled the issue on energy efficiency of the optimal cluster heads. Finally, this paper proposed a D2 D video distribution mechanism that optimized the energy efficiency of cluster heads. Simulation results show that the proposed mechanism is superior to the traditional ones with regard to the energy efficiency of the cluster head and system throughput. [ABSTRACT FROM AUTHOR]

This paper investigated an energy-efficient optimization of massive MIMO systems with energy harvesting. It jointly optimized the power beacon’s transmit power and energy harvesting time to maximize the energy efficiency of the uplink massive MIMO systems under the quality of service (QoS), the power beacon’s transmit power and energy harvesting time constraints. Because the problem was the non-convex optimization problem, it first transformed to the equivalent optimization problem by fractional programming theory. Then, it proposed an energy-efficient power and time allocation algorithm (EPTA) based on the block coordinate descent (BCD) method to find the power of the power beacon, energy harvesting time and energy efficiency of the system iteratively. Compared with time averaged minimum QoS guaranteed algorithm (TA-QoSA) and throughput maximization based power and time algorithm (TPTA), the simulation results show that the proposed algorithm improves the energy efficiency of the system under the guarantee of user’s QoS. [ABSTRACT FROM AUTHOR]

To deal with the problem that CIM should consume a lot of pseudo noise (PN) code resources when it increased the information transmission rate by increasing the number of mapping bits. This paper proposed a novel generalized code index modulation (GCIM). It divided the information bits of the transmitter into mapped bits and modulation bits and mapping modulation bits and mapped bits into modulation symbol and the indexes of the PN code groups respectively. The in-phase part and the orthogonal part of the modulation symbol spread spectrum by selecting activate PN code group respectively. What’s more, by increasing the number of the activate PN code of per transmission slot, which could increase the number of mapped bits and improved the spectral efficiency and energy efficiency of the system. The simulation results show that it is not better than CIM about 2 dB in the additive white Gaussian noise channel and about 1 dB in the Rayleigh fading channel at the same spectral efficiency. Nevertheless, compared with CIM, GCIM consumes significantly less PN code resources. [ABSTRACT FROM AUTHOR]

This paper researched the energy efficiengy of heterogenous cellular networks in homogenous Poisson point process. Firstly, it modeled the heterogenous cellular networks by using homogenous Poisson process. Secondly, it derived the expression of system’s coverage probability and achievable rata in Rayleigh channel situations, and deduced the expression of energy efficiency’s closed form. Finally, it optimized the density of micro-base station via convex-optimum method in order to maximize networks’ energy efficiency. The simulation results show that micro-base station’s density has significant effects on system’s energy efficiency. Its essence is through reasonable setting of micro-base station’s density to available help improve its efficiency. [ABSTRACT FROM AUTHOR]

This paper researched the energy efficiency optimization of simultaneous wireless information and power transfer( SWIPT) in heterogeneous small cellular networks. In order to maximize the energy efficiency of the downlink cellular system, it jointly optimized the splitting ratio of transmit beamforming vector and receive power under both small cellular users’ communication quality and the collected energy, and the transmission power of the small cell base station constraints. The problem belonged to the nonconvex optimization problem, which transformed the equivalent problem by the variable substitution, and then used the subgradient iteration algorithm based on the Lagrange multiplier to solve the problem. The results of computer simulation show that the joint optimization algorithm is simple and effective. [ABSTRACT FROM AUTHOR]

Energy efficiency (EE) has become a new indicator of network performance, and maximizing EE has become a hotspot in communication technology. In order to solve the problem of EE optimization in Macro/Femtocell heterogeneous network (HetNet) , this paper applied the bat algorithm to the problem firstly. Then.it proposed an inertial weight bat algorithm based on exponential decreasing. Aiming at the maximize the network EE as the optimization target.it used the improved algorithm to carry out the carrier allocation under the premise of satisfying the quality of service (QoS) .and compared the performance with the standard bat and genetic algorithm. The simulation results show that the number of carriers and users affects the EE. The proposed algorithm improves the transmission rate of the network and improves the EE by about 11% compared with the genetic algorithm. Experiments show that in the HetNet,the use of improved bat algorithm for carrier allocation can improve EE. [ABSTRACT FROM AUTHOR]

Aiming at the life and coverage optimization of wireless sensor networks,this pager proposed a composite memetic algorithm clustering protocol (CMACP) based on Memetic algorithm and sensor sleep-wake scheduling strategy. The algorithm firstly ran the memetic algorithm to initialize the nodes which need to activate,and planed the neighboring redundant sensors. The genetic algorithm and the local search algorithm could guarantee the optimal initial sensor node distribution. With the operation of the network, when a node lost coverage target due to energy exhaustion .the sleep scheduling strategy selected and activated the optimal neighbor node to make up the override vulnerabilities. Compared with other WSN clustering protocols, the simulation results show that CMACP can better prolong the WSN stable period and improve the coverage ability of WSN ’ s sensing area. [ABSTRACT FROM AUTHOR]

Since the reform and opening up, the urbanization rate in China has risen about 40% from 1978 to 2016, and it has been rapidly advancing at a rate of 0.5 percentage points higher than the world average each year. In the process of city booming, there inevitably exist problems such as extensive land use, urban sprawl and excessive energy consumption. In recent years, environmental pollution such as haze caused by excessive energy consumption has impacted seriously on the life quality of urban residents, and the problem is even more serious in large cities. In western countries, it has been proved that compact city is an effective development mode in alleviating energy shortage and environmental pollution in large cities. However, the concept of compact city has not been given enough attention in China. In this paper, we focused on the relationship between energy efficiency and compactness. The energy efficiency and compactness of 29 large cities during 2003- 2014 were measured with superefficiency- DEA model and entropy value method, and then quadrant map approach was introduced to explore the relationship between urban compactness and energy efficiency. The results showed that energy efficiency was relatively low but was increasing slowly. The regional disparities of the relationship between urban compactness and energy efficiency were significant. The eastern part of China mainly had high coordination relationship, while the middle and western part of China mostly had low coordination relationship. From the perspective of the scale of cities, larger cities had higher energy efficiency. As the city size increased, the proportion of high coordination type became higher and higher. Megacities mostly fell into the categories of high coordination, and small cities mostly fell into the categories of low coordination. The quadrant diagram analysis after eliminating other possible affecting factors showed more obvious result that more compact city had higher energy efficiency. To improve the energy efficiency, multi-functional composite utilization of economy humanity and ecology should be realized by putting more investment into the construction of public service facilities and infrastructure, intensifying industrial land use and perfecting the functional system of cities. [ABSTRACT FROM AUTHOR]

The research of resource allocation for massive MIMO systems currently focuses on the user terminal equipped with a single antenna scenario, but with the development of technology and user needs, the requirement of user intelligent terminal with multiple antennas is increasing. This paper proposed an energy efficient resource allocation algorithm based on multi-antenna multiuser massive MIMO uplink system. Under the condition of satisfying the requirements of user rate and endurance, meanwhile the base station (BS) used a zero forcing (ZF) receiver, this algorithm adopted the convex optimization method to optimize the system after establishing the system energy efficiency function. Firstly, it determined the optimal transmitting power of the user for different antennas. Furthermore, used the dichotomy to determine the number of the activated antennas, and combined the user transmitting power and activated antennas number to optimize the system energy efficiency. The simulation results show that the proposed algorithm can achieve better system efficiency in the case of fewer iterations. [ABSTRACT FROM AUTHOR]

In order to solve the problem of energy efficiency in mobile wireless sensor networks, this paper proposed a mobile wireless sensor network ( WSN) routing protocol based on active region. This method used the relative positions of the source and the sink node to form the active region for routing. The mobile node in the network used a sleep-wakeup pattern to conserve energy. It used the motion vector information, such as current position, direction and speed and the remaining energy of the node to select the neighbors that could provide the maximum connection retention time. It also used the motion vector information to wake up the mobile node in the active area. Experiments show that compared with other routing protocols, this method has higher reliability in packet transmission process. [ABSTRACT FROM AUTHOR]

Under the condition of low ambient temperature in the cold region of the northern China, in the event that biogas project really wants to run normally, it needs to be heated by external heat source Choosing a reasonable heating system for the biogas engineering can not only make the heating system of biogas project more effective and reasonable, but also improve the utilization rate of energy. In addition, choosing a reasonable heating system for biogas engineering is truly the typical practical problem that must be solved to realize the low energy consumption and high output of biogas engineering. According to the application example of the heat pump heating system with the groundwater resource in the biogas project, an energy efficiency analysis model taking exergy efficiency, thermal efficiency, and energy level coefficients as the evaluation criterion for the biogas project heating system was established. Through the measured parameters of ground water source heat pump heating system, the results are obtained as the follows: The user system's exergy efficiency of the biogas project is 97.8%; The exergy efficiency of the groundwater source heat pump unit is 13.4%; The total exergy efficiency of the biogas project heating system is 13.1%; The total thermal efficiency of the heating system is 85.3%; the energy level coefficient of the user's heat consumption in the biogas project is 0.161; the energy level coefficient of the user's supply heat capacity is 0.164, as well as the energy level coefficient of the groundwater source heat pump unit is 0.567. The results indicated that the application of ground water source heat pump heating system in biogas engineering is practical and feasible. For users of low grade thermal energy of the biogas project, the exergy efficiency of using low temperature water for heating is relatively higher, and the process of energy use is quite scientific and reasonable. Moreover, the heat pump unit system can not only recover the low-grade heat energy from the groundwater, but also save the high quality electric energy in a feasible way, so that the effective utilization degree for the amount of energy used in the heating system can be very high, however, there still exists a difference in the quality of supply and demand between the heat source and the users, and the further improvement is needed in the use process of energy quality. It is suggested that the heating system of biogas engineering should adopt the heating mode matching the energy level and use the low grade heat source to heat the biogas project and evaluate the process of energy utilization synthetically. The above conclusion can be used as a reference for selecting a reasonable heating mode for biogas engineering in the future. [ABSTRACT FROM AUTHOR]

In order to study the volatile organic compounds removal in non-thermal plasma,the degradation of toluene exhaust gas is carried out by dielectric barrier discharge. The effects of discharge power and gas flow rate on toluene removal rate, and energy efficiency are studied, and those of produced ozone on the reaction process are also examined.And the plasma characteristics are analyzed by spectroscopy. The results show that increasing the energy density of plasma and discharge power and reducing the gas flow can improve the removal efficiency of toluene, hut the energy efficiency of the reaction is gradually reduced and the energy loss in the reaction process increases. The concentration of ozone generated during the reaction is positive-ly correlated with the toluene removal rate. The generation of ozone coincides with the degradation of toluene. The decomposition of ozone facilitates the degradation of toluene. Oxygen plasma characteristic lines consist of OII lines, OIII lines and OIV spectral lines, and the intensity is enhanced with increasing power. [ABSTRACT FROM AUTHOR]

In order to study the effects of loading rate of stress wave on rock breaking and energy efficiency， 5 hammers with different radius of curvature were designed by using the nonlinear model of the local deformation in the longitudinal impact surface of the members. Incident stress waves with different loading rates were achieved under different and identical incident energy， and the impact test of red sandstones was conducted. The results showed that the fractal dimension of fragmentation of sandstone specimen increases linearly with the increase of the loading rate of stress wave. The fractal dimension of fragmentation of sandstone specimen increases with the increase of incident energy under the same loading rate. The energy dissipation density increases with the increase of loading rate of incident wave. Under the same loading rate， the greater the incident energy is， the greater the energy dissipation density is. The energy efficiency decreases obviously with the increase of the incident energy under different incident energy. In practice， the best incident wave must be designed considering the factors such as rock breaking and the energy efficiency. [ABSTRACT FROM AUTHOR]

In order to enhance the accuracy of spectrum sensing and energy efficiency of cognitive radio Ad hoc networks, this paper proposed a cross-layer design scheme based on energy efficiency. The clustering problem was solved through constraint maximum-weight edge bipartite decomposition scheme based on sensing reliability. Then it optimized the transmission power and the access probability of the secondary users in each cluster. It finally obtained the optimal channel access and power allocation scheme. Simulation results show that the scheme can enhance sensing accuracy of distributed cognitive network by rational clustering and substantially improve the energy efficiency under the premise of ensuring the sensing performance compared with the traditional algorithm. [ABSTRACT FROM AUTHOR]

iming at the optimization problem of mobile sensor network with obstacles in the sensing field,this paper proposed a immune algorithm and voronoi diagram based mobile sensor deployment algorithm. It was divided into two phases ： in the first phase, the multi-objective immune algorithm was used to maximize network coverage and minimize the energy consumption of mobility and sensing of sensors, and Voronoi diagram was used to adjust the sensing ranges of sensors； in the second phase, binary antibody based immune algorithm was used to set the states of sensors, as a result that the dissipated energy caused by sensing and redundant coverage was minimized with preserving the coverage at high level. Several simulation experimental results show that the proposed algorithm realizes better coverage and energy consumption performance to the scenarios with and without obstacles in the target field, at the same time it realizes shorter process time. [ABSTRACT FROM AUTHOR]

This paper deals with regional energy efficiency and energy total-factor efficiency (TFE) indexes in China using weighted Russell directional distance function. We find the differences in inefficiency values among regions in China are significant. Then, we decompose the gross inefficiency term to energy inefficiency values and other indicators' inefficiency, and we find that the inefficiency values of energy are not big. This means that the main sources of inefficiency are not, energy inefficiency. Finally, we analyze the growth in energy total-factor efficiency index and find most of provinces were positive, which indicates that the growth of energy efficiency have positive effects on TFE in provincial economies. [ABSTRACT FROM AUTHOR]

Generally the size of farmland is large. It is high cost and poor flexibility to use wired network. Aiming at this situation, a farmland environment monitoring system by using the ZigBee wireless sensor network technology as the core and a scheme on node energy optimization are presented. This system includes two parts ： the information collection and the data storage. The information collection consists of end-node，router-node and coordinator-node. Parameters such as temperature, humidity and soil electric conductivity are measured by end-node and router-node. Coordinator-node is responsible for collecting datum. The data storage consists of server and computer. The experimental result shows that the network which uses energy aware and energy efficiency method can live longer and send more data. This monitoring system may provide data support to the development of precision agriculture. [ABSTRACT FROM AUTHOR]

In order to improve the energy efficiency of cognitive radio networks, this paper proposed an algorithm of joint optimization based on energy-efficient. It established an energy efficiency model based on the consideration of the interference tolerance of the primary user. The algorithm decomposed the optimization objective into solution of access policy and power optimization problem. It adopted particle swarm optimization algorithm with iterative calculation and obtained the optimal solution. Simulation results indicate that compared with traditional optimal schemes not taking power allocation or access probability into consideration, the proposed algorithm can effectively improve the energy efficiency of the system. [ABSTRACT FROM AUTHOR]

Life cycle assessment analysis method was used to establish the life-cycle energy consumption and emission inventory, and evaluate the environmental impacts of bioethanol production produced from sweet potato with two different fertilization modes, that is, conventional fertilization mode and soil testing & formulating fertilization mode. The sweet potato based ethanol production system was divided into three subsystems, including crop cultivation, feedstock transport and ethanol conversion. The energy consumption and pollutant emission inventory of sweet potato based ethanol was established with the unit of 1 000 L ethanol production. The results show that the energy efficiencies of the two sweet potato based ethanol production systems were 1.41 and 1.43. The main environmental impacts of ethanol produced from sweet potato with conventional fertilization practice are human toxicity, eutrophication, acidification, freshwater ecotoxicity, energy depletion and global warming, their environmental impact potentials accounting for 40%, 40%, 31%, 29%, 25% and 20% of relevant environmental potential per capita in 2000. The soil test & formulating fertilization practice reduced the usage of chemical nitrogen and phosphate fertilizers and increased the fertilizer utilization efficiency and sweet potato yielding, so the environmental impact indexes of eutrophication, freshwater ecotoxicity, acidification and global warming were decreased by 31%, 15%, 9% and 7%, respectively. Therefore, soil testing & formulating fertilization mode can improve life-cycle energy efficiency of the sweet potato based bioethanol and significantly alleviate its negative environmental impacts. [ABSTRACT FROM AUTHOR]

Penaeus vannamei is the agricultural product with high nutrition and delicious taste. It is becoming increasingly popular in both domestic and foreign consumers and has realized its health benefits to people. But Penaeus vannamei is a kind of product with seasonal characteristics for harvest and has short storage period due to the vulnerability to infection by the microbes and spoilages during storage. As a result, we may suffer a great loss in the end. So the drying of Penaeus vannamei is becoming an important processing. The drying of Penaeus vannamei is mainly the traditional natural drying at present. It has many disadvantages: products being spoilt due to wind, rain, and dust, great loss due to animals and birds, and deterioration due to decomposition by fungi and insect. Further, the process will spend much time, need a lot of labors and occupy a large area for spreading the produce out to dry. So the natural drying under the open sky can not guarantee the quality of final products. It is difficult to meet the needs of industrial production. The drying using coal-fire needs a lot of energy consumption and causes heavy pollution during the drying process. Whatever, the artificial mechanical drying such as vacuum freeze-drying and hot-air drying is energy intensive and expensive, and it will ultimately increase the product cost. Solar drying system can process Penaeus vannamei in clean and sanitary conditions. It takes little time and energy, occupies fewer areas and improves product quality. Solar drying is efficient and can protect the environment. To reduce the Penaeus vannamei drying energy consumption and improve the drying quality, the effects of solar drying temperature, drying capacity and airflow rate on the drying process were investigated in the laboratory. The results showed that the increase of the drying temperature and airflow rate and the reduction of the drying capacity could improve the drying rate and shorten the drying time. In the later stage of drying, the effect of drying parameters on water activity was significant. Different drying temperature had significant effect on the texture of Penaeus vannamei after rehydration. The change of color was not so obvious with different drying parameters but had a big difference with raw Penaeus vannamei. The 3 drying parameters had significant effect on dry shrinkage and rehydration ratio. With the increase of temperature and airflow rate, the energy consumption had a significant increase. Increasing the drying capacity could improve the utilization of the energy consumption. The drying time also had much relationship with the energy consumption. Through laboratory experiment, the drying temperature was 45-55 ℃, airflow rate was 6-8 m/s, and drying capacity was 3-4 kg. And the relationships between the drying temperature, drying capacity and airflow rate and energy consumption were analyzed through the response surface method. The quadratic regression models were established. The optimal parameters were as follows: solar drying temperature of 53.40 ℃, airflow rate of 7.43 m/s, and drying capacity of 3.65 kg. Based on the laboratory test, the pilot scale test of solar drying of Penaeus vannamei was carried out. It have dried 100 kg Penaeus vannamei (69.5 kg after Salt solution pre-cooking) , got 38.16 kg final product and took 4.5 hours. The total energy consumption of solar drying was 549 827.05 kJ, including effective use of solar energy 379 619.05 kJ and the electric power 47.28 kW·h. The energy consumption was 0.68 kW·h/kg.Compared with electric heating drying,it could save 1.51 kW·h/kg energy consumption. Compared with coal drying, it could make 0.75kg/kg CO2 emission reduction. The results will provide the basis for the industrial production of Penaeus vannamei solar drying. [ABSTRACT FROM AUTHOR]

This paper studied how to derive a fair tradeoff between two important traffic engineering objectives： load balance and energy efficiency. To this end, it introduced threat value game based on Nash bargaining framework to negotiate the traffic routing. In case a unfair solution or negotiation broke down, it modified the threat value game to have a repeated process and designed a mechanism to not only guarantee an agreement, but also generate a fair solution. Both mathematic analysis and application in NSFNET show that this method is easy to deploy and can derive a fair tradeoff between load balance and energy efficiency in the network. [ABSTRACT FROM AUTHOR]

For the issue that data conflict and overhearing existing in wireless sensor network will impact energy efficiency of the MAC protocol, this paper proposed a transmit-based and receive-based slot allocation strategy of TDMA-MAC. It calculated the energy consumption of WSN by considering different times of cost of wireless transceiver pattern (sending, receiving, dormancy and leisure).Suppose WN packet interval in clustering was exponential distribution, two-stage TDMA method was used to implement the evaluation of multi-step clustering. It verified the effectiveness of proposed model by simulation done by OPNET Modeler. Simulation results show that the energy efficiency of receive-based SAS is five times as well as transmit-based. Proposed protocol saves 4.3% energy and reduces 0.35 ms delay comparing with hybrid TDMA/CDMA protocol based on clustering. It saves 10.8% energy and reduces 1 ms delay comparing with hybrid TDMA/CDMA protocol based on clustering. [ABSTRACT FROM AUTHOR]

With the use and depletion of fossil fuels, environmental pollution and energy crisis have become the biggest obstacles to the survival and development of human beings. Biomass energy utilization is an important way to solve this problem as it has wide source of raw material, and is clean and renewable. Biochar is an important form of biomass energy utilization, and it can not only change the waste straw into biomass energy, but also help reduce the greenhouse effect. The yield is a basic index in the study of pyrolysis technology; while the biochar is used as fuel, its calorific value is the factor directly reflecting the quality. These 2 indices are both necessary during the research. However, the existing research on the pyrolysis process of biochar is limited to all kinds of independent indices, and the optimal pyrolysis process is always not the same. In this paper, the advantages and disadvantages of pyrolysis process for biochar production were evaluated by the yield, calorific value and energy efficiency in order to design and optimize the process of carbonization of cotton stalk. The effects of the temperature, retention time and particle size on the yield and heating value of the biomass were studied; and the typical cotton stalk was taken as raw material to produce biochar under nitrogen gas atmosphere by slow pyrolysis. The results showed that: 1) The effects of pyrolysis temperature on the yield and heating value of the biomass were significant; the biochar yield was negatively correlated with heating value, and with the increase of the temperature, the yield of biochar decreased gradually, while the calorific value increased gradually. 2) The effect of retention time on the yield and heating value of the biochar was obvious, but it was not as obvious as the pyrolysis temperature; at the same time, it could be seen that the yield and heating value were negatively correlated, and with the increase of the retention time, the biochar yield decreased, while the calorific value increased. 3) Compared with the first 2 conditions, there was no significant change in the yield and heating value when the raw material particle size changed, which showed that the effects of particle size on the yield and calorific value were small. In addition, according to the general trend, we could still see a negative correlation between heating value and yield. Energy efficiency (ratio of total energy yield of biochar to energy yield of raw material) was proposed to coordinate the yield and calorific value, and the response surface analysis of the energy efficiency was carried out, from which the energy efficiency model was got. The results showed that when the temperature was 429℃, the retention time was 1.29 h, and the particle size was 0.32 mm, the predicted energy efficiency from the model reached the highest value, which was 78.95%. The model is validated by the experiment. The model can be used to guide the production of biochar with high energy efficiency, and provide the reference for energy efficient utilization. [ABSTRACT FROM AUTHOR]