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The rational allocation of industrial factors in resource-based cities is a necessary condition for promoting high-quality economic development. To systematically measure the mismatch of industrial factors, this study integrates the production function model and accounting framework of Aoki (2012). The capital, labor, and energy factors are integrated into the overall measurement framework, and the factor mismatch calculation model is innovatively constructed at the city level. To effectively reflect the factor mismatch of different cities, the relative distortion coefficient of factor price is introduced to establish the relationship between the distortion of factor-use cost and effectiveness of resource allocation. The degree and direction of factor mismatch are effectively measured. This study takes China's resource-based cities as the research object. To avoid the impact of the COVID-19 pandemic, data on 114 resource-based cities in China from 2003 to 2018 are selected, and 164 non-resource-based cities are used as the control group to evaluate the factors affecting the transformation of such cities. Regarding the diversity of resource-based cities in China, this study compares the characteristics of factor misallocation in these cities for different growth stages, geographical regions, and dominant resources. Finally, this study finds that on average, the cities' degree of energy misallocation is the most serious, and the degree of labor misallocation ranks second. The degree of capital misallocation ranks the lowest, but the misallocation of various factors is very different in different situations. Therefore, different types of cities should make detailed policy adjustments in various transformation directions according to the calculation results.

The influences of applied pressure on the structure, mechanics, dislocation, and electronics properties of an FeTi hydrogen storage alloy are theoretically investigated via first-principles calculations. The lattice parameter ratio, elastic constant, Young's modulus, bulk modulus, shear modulus, ductile/brittle, Poisson's ratio, anisotropy, Cauchy pressure, yield strength, Vickers hardness and energy factor are discussed versus applied pressure. The results show that the FeTi alloy exhibits good mechanical stability under applied pressure between 0 and 50 GPa, and the mechanical properties are significantly improved under applied pressure, like the resistances to elastic, bulk, and shear deformations, the material ductility and metallicity, as well as Vickers hardness and yield strength. Moreover, the electronic structures reveal that the FeTi alloy has metallic properties and the structural stability of the FeTi hydrogen storage alloy is enhanced at high pressure. This work provides significant value for high-pressure applications of FeTi alloys in hydrogen storage and supply fields. [ABSTRACT FROM AUTHOR]

Effects of Al and La elements on mechanical properties of CoNiFe0.6Cr0.6 high-entropy alloys (HEAs) with face-centered cubic (FCC) structure were investigated by first-principles calculations. The variation curves of relevant physical parameters, including lattice constants, formation enthalpy, elastic constants, elastic modulus, Poisson's ratio, Pugh's ratio, Cauchy pressure, anisotropy factors, Vickers hardness, yield strength, and energy factor, as a function of Al and La concentration were discussed in detail. Results show that the resistances to bulk, elastic, and shear deformation decrease with the increase of Al and La concentration. The addition of Al and La can improve the plasticity and ductility of HEAs. Meanwhile, with the increase of Al and La concentration, the metallic characteristic of atomic bonding strengthens and the anisotropy of materials increases. Moreover, the energy factor indicates that the addition of Al and La could promote dislocation nucleation. This study provides a guideline for further research on non-equiatomic CrFeCoNi series HEAs with designed mechanical properties.

Important for promoting the integrated protection and systematic management of mountains, rivers, forests, farmlands, lakes, grasslands, and sandy areas, ecological networks form the backbone of the regional ecological security pattern. An improved morphological spatial pattern analysis coupled with a minimum cumulative resistance model (MSPA–MCR) based on multi-source data was used to study, on a provincial scale, the ecological security pattern of Ningxia, an ecologically fragile region in the upper reaches of the Yellow River in China. The results show the following: (1) A reasonable classification of ecological sources and ecological corridors is key to constructing hierarchical ecological networks. Classifying ecological sources by replacing patch areas with energy factors and identifying the importance of ecological corridors by modifying the gravity model with the energy factors proposed in this paper could improve the rationality of the hierarchical structure division of ecological networks. (2) Grassland as the substrate vegetation type is an important ecological source type in arid and semi-arid ecologically fragile areas, and forests and lake wetlands are the main ecological source types in mountainous areas and oasis areas, respectively. The study area was located in the arid–semi-arid transitional area, with a variety of ecological types, such as mountain, oasis, and desert. Therefore, the complex ecological source types of forest–grassland–wetland appear in some areas. (3) There are 45 ecological patch groups that can be classified as ecological sources in Ningxia, including 10 primary source groups. The number of primary source groups is small, and their spatial distribution is unbalanced. There are two categories of ecological corridors, the river corridor and the mountain corridor, and the network connectivity is poor. (4) The ecological network structure of Ningxia is presented as an ecological security structure consisting of one belt, three screens, three corridors, and five clusters, forming a hierarchical nested ecological network security structure system. [ABSTRACT FROM AUTHOR]

This paper focused on the performance monitoring and modeling of a 6.0 kW, 2000 L hybrid direct expansion solar assisted heat pump (DX-SAHP) water heater used for the production of hot water in a university students' accommodation with 123 females. The data of total electrical energy consumed, volume of hot water consumed, ambient temperature, relative humidity, and solar irradiance were obtained from the data acquisition systems and analyzed in conjunction with the energy factor (EF) of the system. A multiple linear regression model was developed to predict the EF. The EF of the hybrid DX-SAHP water heater was determined from the summation of the coefficient of performance (COP) of the heat pump unit and the solar fraction (SF) of the solar collectors. The operations of the hybrid energy system were analyzed based on three phases (first phase from 00:00–08:00, second phase from 08:30–18:30, and third phase from 19:00–23:30) over 24 h for the entire monitoring period. The average EF of the hybrid energy system per day during the second phase of operation was 4.38, while the SF and COP were 0.697 and 3.683, respectively. The developed multiple linear regression model for the hybrid DX-SAHP water heater accurately predicted the determined EF. [ABSTRACT FROM AUTHOR]

Weak magnetic detection technology is an effective method to identify stress-induced damage to ferromagnetic materials, and it especially possesses great application potential in long-distance oil and gas pipeline weld crack detection. In the process of pipeline operation, due to internal pressure and external loads, local stress concentration may be generated, and partial stress concentration may lead to local cracks and expansion of the pipe. In order to improve the accuracy of magnetic signal analysis for ferromagnetic materials under internal pressure, the causes of magnetic signal generation at pipeline welds were analyzed from a microscopic perspective. The distributions of magnetic signals at pipeline welds, weld cracks, and base metal cracks under different internal pressures were numerically analyzed. The variation trends of magnetic signal characteristics, such as peak values of axial and radial components, gradient K, maximum gradient Kmax, and gradient energy factor S(K), were analyzed. In addition, experiments were carried out to verify the numerical data. It was revealed that with the elevation of internal pressure, the peak values of the axial and radial components, gradient K, maximum gradient Kmax, and gradient energy factor S(K) linearly increased. However, the magnitude and average change of S(K) were larger, which can more directly indicate variations of magnetic signals. The radial growth rate νy of S(K) was 3.24% higher than the axial growth rate νx, demonstrating that the radial component of the magnetic signal was more sensitive to variations of stress. This study provided a theoretical and experimental basis for detection of stress-induced damage to long-distance oil and gas pipelines. [ABSTRACT FROM AUTHOR]

The influences of applied pressure on the structure, mechanics, dislocation, and electronics properties of an FeTi hydrogen storage alloy are theoretically investigated via first-principles calculations. The lattice parameter ratio, elastic constant, Young’s modulus, bulk modulus, shear modulus, ductile/brittle, Poisson’s ratio, anisotropy, Cauchy pressure, yield strength, Vickers hardness and energy factor are discussed versus applied pressure. The results show that the FeTi alloy exhibits good mechanical stability under applied pressure between 0 and 50 GPa, and the mechanical properties are significantly improved under applied pressure, like the resistances to elastic, bulk, and shear deformations, the material ductility and metallicity, as well as Vickers hardness and yield strength. Moreover, the electronic structures reveal that the FeTi alloy has metallic properties and the structural stability of the FeTi hydrogen storage alloy is enhanced at high pressure. This work provides significant value for high-pressure applications of FeTi alloys in hydrogen storage and supply fields.

Important for promoting the integrated protection and systematic management of mountains, rivers, forests, farmlands, lakes, grasslands, and sandy areas, ecological networks form the backbone of the regional ecological security pattern. An improved morphological spatial pattern analysis coupled with a minimum cumulative resistance model (MSPA–MCR) based on multi-source data was used to study, on a provincial scale, the ecological security pattern of Ningxia, an ecologically fragile region in the upper reaches of the Yellow River in China. The results show the following: (1) A reasonable classification of ecological sources and ecological corridors is key to constructing hierarchical ecological networks. Classifying ecological sources by replacing patch areas with energy factors and identifying the importance of ecological corridors by modifying the gravity model with the energy factors proposed in this paper could improve the rationality of the hierarchical structure division of ecological networks. (2) Grassland as the substrate vegetation type is an important ecological source type in arid and semi-arid ecologically fragile areas, and forests and lake wetlands are the main ecological source types in mountainous areas and oasis areas, respectively. The study area was located in the arid–semi-arid transitional area, with a variety of ecological types, such as mountain, oasis, and desert. Therefore, the complex ecological source types of forest–grassland–wetland appear in some areas. (3) There are 45 ecological patch groups that can be classified as ecological sources in Ningxia, including 10 primary source groups. The number of primary source groups is small, and their spatial distribution is unbalanced. There are two categories of ecological corridors, the river corridor and the mountain corridor, and the network connectivity is poor. (4) The ecological network structure of Ningxia is presented as an ecological security structure consisting of one belt, three screens, three corridors, and five clusters, forming a hierarchical nested ecological network security structure system.

The manufacturing process of cement emits one metric ton of carbon dioxide greenhouse gas. Considering the situation reducing the gas emission without affecting cement production, industrial wastes like metakaolin (MK) can be partially replaced with cement due to high pozzolanic reactivity to arrive the high-strength concrete. This present examination attentions on the obtaining optimum percentage of metakaolin to be substituted for cement proportion and aims to determine the concrete sample’s mechanical characteristics, equivalent CO _2 emissions, and energy factor for environmental advantages through comparison with metakaolin varied from 0% to 20% at 5% incremental rate was determined and compared with the conventional control mix. Concrete samples are tested at the periodical interval of 7, 14, and 28 days in addition results, 5% of metakaolin is the optimum percentage to be replaced for cement in concrete. The negative sign implies that replacing binder with MK gradually decreases energy requirements (−2.16% to −7.74%) as well as carbon dioxide emissions (−4.17% to −15.41%). The use of mineral admixture like high reactive metakaolin additional cementitious elements has a considerable effect and may have an impact on the creation of environmentally friendly, sustainable concrete. In conclusion, effective utilization of high reactive metakaolin in high-strength concrete leads to substantial cost, and reducing global gas emissions eventually reduces energy consumption and a notable decrease in environmental pollution.

This paper focused on the performance monitoring and modeling of a 6.0 kW, 2000 L hybrid direct expansion solar assisted heat pump (DX-SAHP) water heater used for the production of hot water in a university students’ accommodation with 123 females. The data of total electrical energy consumed, volume of hot water consumed, ambient temperature, relative humidity, and solar irradiance were obtained from the data acquisition systems and analyzed in conjunction with the energy factor (EF) of the system. A multiple linear regression model was developed to predict the EF. The EF of the hybrid DX-SAHP water heater was determined from the summation of the coefficient of performance (COP) of the heat pump unit and the solar fraction (SF) of the solar collectors. The operations of the hybrid energy system were analyzed based on three phases (first phase from 00:00–08:00, second phase from 08:30–18:30, and third phase from 19:00–23:30) over 24 h for the entire monitoring period. The average EF of the hybrid energy system per day during the second phase of operation was 4.38, while the SF and COP were 0.697 and 3.683, respectively. The developed multiple linear regression model for the hybrid DX-SAHP water heater accurately predicted the determined EF.

Weak magnetic detection technology is an effective method to identify stress-induced damage to ferromagnetic materials, and it especially possesses great application potential in long-distance oil and gas pipeline weld crack detection. In the process of pipeline operation, due to internal pressure and external loads, local stress concentration may be generated, and partial stress concentration may lead to local cracks and expansion of the pipe. In order to improve the accuracy of magnetic signal analysis for ferromagnetic materials under internal pressure, the causes of magnetic signal generation at pipeline welds were analyzed from a microscopic perspective. The distributions of magnetic signals at pipeline welds, weld cracks, and base metal cracks under different internal pressures were numerically analyzed. The variation trends of magnetic signal characteristics, such as peak values of axial and radial components, gradient K, maximum gradient Kmax, and gradient energy factor S(K), were analyzed. In addition, experiments were carried out to verify the numerical data. It was revealed that with the elevation of internal pressure, the peak values of the axial and radial components, gradient K, maximum gradient Kmax, and gradient energy factor S(K) linearly increased. However, the magnitude and average change of S(K) were larger, which can more directly indicate variations of magnetic signals. The radial growth rate νy of S(K) was 3.24% higher than the axial growth rate νx, demonstrating that the radial component of the magnetic signal was more sensitive to variations of stress. This study provided a theoretical and experimental basis for detection of stress-induced damage to long-distance oil and gas pipelines.

The rational allocation of industrial factors in resource-based cities is a necessary condition for promoting high-quality economic development. To systematically measure the mismatch of industrial factors, this study integrates the production function model and accounting framework of Aoki (2012). The capital, labor, and energy factors are integrated into the overall measurement framework, and the factor mismatch calculation model is innovatively constructed at the city level. To effectively reflect the factor mismatch of different cities, the relative distortion coefficient of factor price is introduced to establish the relationship between the distortion of factor-use cost and effectiveness of resource allocation. The degree and direction of factor mismatch are effectively measured. This study takes China's resource-based cities as the research object. To avoid the impact of the COVID-19 pandemic, data on 114 resource-based cities in China from 2003 to 2018 are selected, and 164 non-resource-based cities are used as the control group to evaluate the factors affecting the transformation of such cities. Regarding the diversity of resource-based cities in China, this study compares the characteristics of factor misallocation in these cities for different growth stages, geographical regions, and dominant resources. Finally, this study finds that on average, the cities' degree of energy misallocation is the most serious, and the degree of labor misallocation ranks second. The degree of capital misallocation ranks the lowest, but the misallocation of various factors is very different in different situations. Therefore, different types of cities should make detailed policy adjustments in various transformation directions according to the calculation results., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Runqun Yu reports financial support was provided by Liaoning Social Science Planning Fund Office., (© 2024 The Authors.)

Video processing software is often used to remove specific moving foreground from a video. Existing forgery algorithms for detecting this type of tampering generally suffer from inefficiency and are not effective for the forged videos under complex background. To address these problems, we propose a novel forgery detection algorithm for detecting video foreground removal. The algorithm first calculates the energy factor (EF) of each frame to identify forged frames. An adaptive parameter-based visual background extractor (AVIBE) algorithm is then designed to detect suspected regions from the forged frames determined in the first stage. After eliminating false detection by calculating the difference of EF between suspected regions in the forged frames and the corresponding regions in the authentic frames, the algorithm finally locates the tampering traces. The experimental results show that our proposed algorithm has higher computational efficiency and accuracy as well as better robustness than those of previous algorithms.

The utilization of a hybrid energy system (combined solar water heater (SWH) and an air source heat pump (ASHP) water heater) can result in over 80% reduction in the electrical energy consumed as the system is capable to operate with an energy factor of above 4.0. A major challenge is to develop credible methodology or mathematical model to predict energy savings. The research focused on the design and installation of a hybrid energy system and a data acquisition system to monitor its performance. The average weekday volume of hot water consumed, thermal energy gained by water in the tank of the air source heat pump (ASHP) water heater, electrical energy consumed, and the COP were 225.03 L, 5.25 kWh, 1.52 kWh, and 3.50. The average weekday global solar radiation, ambient temperature, solar fraction of the solar water heater (SWH) and the energy factor of the hybrid energy system were 579.67 W/m2, 23.58°C, 0.52, and 4.02, respectively. A multiple linear regression model was developed to predict the energy factor of the hybrid energy system. Both the modelled and validated results showed very good determination coefficients of 0.952 and 0.935, with the trained and validated dataset. Hence, by employing both multiple linear regression model and a multiple 2D contour plot simulation, the energy factor and the variation of the input parameters can be accurately determined. The developed model can help homeowners, energy service companies, and policy makers to appreciate and confidently support the rollout of the technology for sanitary water heating.

The utilization of a hybrid energy system (combined solar water heater (SWH) and an air source heat pump (ASHP) water heater) can result in over 80% reduction in the electrical energy consumed as the system is capable to operate with an energy factor of above 4.0. A major challenge is to develop credible methodology or mathematical model to predict energy savings. The research focused on the design and installation of a hybrid energy system and a data acquisition system to monitor its performance. The average weekday volume of hot water consumed, thermal energy gained by water in the tank of the air source heat pump (ASHP) water heater, electrical energy consumed, and the COP were 225.03 L, 5.25 kWh, 1.52 kWh, and 3.50. The average weekday global solar radiation, ambient temperature, solar fraction of the solar water heater (SWH) and the energy factor of the hybrid energy system were 579.67 W/m2, 23.58°C, 0.52, and 4.02, respectively. A multiple linear regression model was developed to predict the energy factor of the hybrid energy system. Both the modelled and validated results showed very good determination coefficients of 0.952 and 0.935, with the trained and validated dataset. Hence, by employing both multiple linear regression model and a multiple 2D contour plot simulation, the energy factor and the variation of the input parameters can be accurately determined. The developed model can help homeowners, energy service companies, and policy makers to appreciate and confidently support the rollout of the technology for sanitary water heating. [ABSTRACT FROM AUTHOR]

Energy required for water heating accounts for approximately 40percent of national residential natural gas consumption in California. With water heating contributing such a substantial portion of natural gas consumption, it is important to pay attention to water heater efficiencies. This paper reports on an investigation of a patented, buoyancy-operated flue damper. It is an add-on design to a standard atmospherically vented natural-draft gas-fired storage water heater. The flue damper was expected to reduce off-cycle standby losses, which would lead to improvements in the efficiency of the water heater. The test results showed that the Energy Factor of the baseline water heater was 0.576. The recovery efficiency was 0.768. The standby heat loss coefficient was 10.619 (BTU/hr-oF). After the damper was installed, the test results show an Energy Factor for the baseline water heater of 0.605. The recovery efficiency was 0.786. The standby heat loss coefficient was 9.135 (BTU/hr-oF). The recovery efficiency increased 2.3percent and the standby heat loss coefficient decreased 14percent. When the burner was on, the baseline water heater caused 28.0 CFM of air to flow from the room. During standby, the flow was 12.4 CFM. The addition of the damper reduced the flow when the burner was on to 23.5 CFM. During standby, flow with the damper was reduced to 11.1 CFM. The flue damper reduced off-cycle standby losses, and improved the efficiency of the water heater. The flue damper also improved the recovery efficiency of the water heater by restricting on-cycle air flows through the flue. With or without the flue damper, off-cycle air flow up the stack is nearly half the air flow rate as when the burner is firing.

This study quantifies the potential of a 4.0 kW air source heat pump (ASHP) unit retrofitted to a 12.0 kW, 1000 L electric boiler coupled to a 1000 L storage tank. A data acquisition system was built to monitor the performance of the electric boiler and the ASHP water heater. The annual electrical energy saving and the load factor reduction from the electric boiler because of the ASHP unit retrofit was 34,805.94 kWh and 0.124. The net present value payback period of the ASHP system was 1.60 years. A Wilcoxon rank sum test was employed to compare both the volumes of hot water and electrical energy consumed by the two systems. Linear regression models of the daily volumes of hot water and electrical energy consumed by both systems were established. The results should be of great value to the management of universities that are considering energy-efficient interventions with a significant return on investment.

The increase in the number of space debris is a serious threat to the safe operation of in-orbit spacecraft. The propagation law of the impact signal in the stiffened panel of the spacecraft's sealed bulkhead is very complicated, and there is less research on the impact source location in the high-stiffened panel. In this paper, an adaptive energy compensation threshold filtering (AECTF) method based on acoustic emission is proposed, which can realize large-scale, fast and accurate locating of the impact source on the stiffened panel with less resource consumption. The influence law of the stiffeners on the lamb wave is analyzed by finite element simulation, and the Lamb wave energy factor curve is obtained. The correctness of the simulation is verified by the locating experiment on the impact point. The results show that the proposed AECTF method has better adaptability and can correctly locate the impact points in complicated locations. By selecting the appropriate frequency band to filter the signal, the locating accuracy and stability can be improved. When the frequency band is 100–200 kHz, the locating result is optimal, the average absolute error is 7.0 mm, the average relative error is 0.86%, and the error standard deviation is 3.5 mm. This study will generate fresh insight into the impact location technology of high-stiffened panel and provide a reference for the in-orbit spacecraft health monitoring system. [ABSTRACT FROM AUTHOR]

Referenced article is the overview of the important scientific problem – determination of the power industry influence on the US-China international relations within the Persian Gulf region. Persian Gulf region plays a really important role within the system of the global energy security. Hence, high importance is allocated to the power industry as Chinese factor of influence in the Middle East and its role in the US-China international relations. Within the post-bipolarperiod, political influence of China in the Persian Gulf region is substantially growing. US attempts to unilaterally control security in the Gulf is opposed by Chinese establishment of relations with those countries of the region, who are falling within its geopolitical and geoeconomical sphere of interst. It is defined a set of peculiarities of China’s interaction with the other external actors in context of regional rivalry for influence in the region. It is proved that as China, unlike the United States, does not determine a general direction of geopolitical processes in Persian Gulf, US policy in the Region is the main external determinant for Chinese foreign policy strategy formation and implementation, and energy security of China will mostly depend on the level of cooperation and understanding between China and the United States. It is proven that an essential tool for ensuring economic interests of China in Persian Gulf is to prevent strengthening of geopolitical influence of other external actors by creating alternatives based on potential of Chinese economy

The meaning of the energy factor in the system of security US vital interests was investigated. The role of the region’s Gulf states in the energy policy of the United States was defined and the special importance of post-war Iraq in order U.S. energy security was studied. The sense of the energy factor was considered as a foreign policy tool that belong to the elements of «hard power». It was studied the instruments of political and economic cooperation between the USA and Persian Gulf countries. The energy strategy of the United States was detailed analyses, in the framework of which it was comprehensively studied the mechanisms for combating the energy dependence as well as the use of preventive mechanisms of the crisis management in the energy policy. It was defined the policy tools of oil security supply by the states of the Persian Gulf. The role of the US law «No Oil Producing and Exporting Cartels Act of 2007/ HO Congress 2007-2008» as a political tool to ensure oil security of the U.S. was established. It is proved that in conditions of high dependence of the economic system from energy prices in the world market, the oil factor played the dominant factor in the anti-Iraqi company in 2003. It was noted the importance meaning for political stability of Iraq the Bill of Oil, which aimed to facilitate reconciling different religious communities in the country (Sunnis, Shiites and Kurds), through the distribution of state oil income among them.

In the existing key node decision methods for wireless sensor network,the judgment index was so single that the result judged was deficient.In order to solve this problem,a new key node decision algorithm(KNDA)based on local information and energy factor was proposed.Firstly,the local information model based on the degree and neighbor information of node was established.Secondly,according to the residual energy of node and the change of network energy consumption after the node failed,the models of energy factors were established.Finally,an aggregative key node decision model was formed.Extensive simulation experiments were carried out in the MATLAB simulation platform,by comparing with other algorithms,the results verify that the key nodes obtained by this algorithm are more sufficient.Meanwhile when the key nodes judged by KNDA are protected,the network can show strong invulnerability.

Energy consumption is one of the most crucial issues in the table grapes supply chain. However, the potential for energy conservation assessment is still limited because of the complexity of the process. The aim of this paper is to propose an energy conservation potential assessment method in order to increase energy consumption transparency and help managers take appropriate energy conservation measures to reduce the energy consumption in the table grapes supply chain. The conservation potential assessment in three kinds of the supply chain modes (the normal chain, the cold insulation chain and the cold chain), were realized by integrating the actual energy consumption investigated with the unified energy consumption per unit energy factor that represents the energy consumption throughout the entire product lifecycle. According to the comprehensive analysis of the energy consumption compared with the energy conservation potential in actual supply chain of table grapes, the proposed energy conservation potential assessment method could provide a unified method for evaluating the energy conservation potential in different supply chain mode of table grapes. The energy conversation potential in cold insulation chain, which was about 0.985, was the highest and that in cold chain, which was about 0.935, was the smallest. However, the cold chain was still the optimal supply chain for the table grapes because of the characteristics of the longest storage shelf life and the lowest quality decay, and the cold chain energy consumption would be further reduced by adopting the more advanced refrigeration and preservation technologies. The proposed energy conservation potential assessment method could be extended for other supply chain applications to evaluate their own energy conservation potential, and thus, reduce their energy consumption. [ABSTRACT FROM AUTHOR]

The increase in the number of space debris is a serious threat to the safe operation of in-orbit spacecraft. The propagation law of the impact signal in the stiffened panel of the spacecraft’s sealed bulkhead is very complicated, and there is less research on the impact source location in the high-stiffened panel. In this paper, an adaptive energy compensation threshold filtering (AECTF) method based on acoustic emission is proposed, which can realize large-scale, fast and accurate locating of the impact source on the stiffened panel with less resource consumption. The influence law of the stiffeners on the lamb wave is analyzed by finite element simulation, and the Lamb wave energy factor curve is obtained. The correctness of the simulation is verified by the locating experiment on the impact point. The results show that the proposed AECTF method has better adaptability and can correctly locate the impact points in complicated locations. By selecting the appropriate frequency band to filter the signal, the locating accuracy and stability can be improved. When the frequency band is 100−200 kHz, the locating result is optimal, the average absolute error is 7.0 mm, the average relative error is 0.86%, and the error standard deviation is 3.5 mm. This study will generate fresh insight into the impact location technology of high-stiffened panel and provide a reference for the in-orbit spacecraft health monitoring system.

A time-domain design methodology for voltage regulation control of dc-dc boost and buck-boost converters based on a multi-loop controller with PI regulator for the outer loop and an inner loop with sliding mode current controller has been developed for renewable energy applications such as photovoltaic (PV)-fed dc-dc converters. This paper proposes a new method for the design of PI regulators in such multi-loop control scheme. The proposed design presents a simple analytical method for selecting controller gains and has been validated by simulation as well as hardware implementation. Also, this paper presents an illustrative example based on the proposed design for the voltage regulation control of PV-fed boost converters for off-grid applications. The simulation results for varying irradiation, temperature and load along with stability analysis have been presented in this paper. The proposed controller is implemented in hardware for a 1.1 kW PV-array-fed boost converter. Performance analysis based on field test results using real-time weather data validates the proposed design. Therefore the proposed controller could be considered as an attractive solution for off-grid renewable energy applications like PV- or fuel-cell-fed dc-dc converter, where the variations are stochastic in nature. [ABSTRACT FROM AUTHOR]

Experiments on hippocampal slices have recorded that a novel pattern of epileptic seizures with alternating excitatory and inhibitory activities in the CA1 region can be induced by an elevated potassium ion (K) concentration in the extracellular space between neurons and astrocytes (ECS-NA). To explore the intrinsic effects of the factors (such as glial K uptake, Na-K-ATPase, the K concentration of the bath solution, and K lateral diffusion) influencing K concentration in the ECS-NA on the epileptic seizures recorded in previous experiments, we present a coupled model composed of excitatory and inhibitory neurons and glia in the CA1 region. Bifurcation diagrams showing the glial K uptake strength with either the Na-K-ATPase pump strength or the bath solution K concentration are obtained for neural epileptic seizures. The K lateral diffusion leads to epileptic seizure in neurons only when the synaptic conductance values of the excitatory and inhibitory neurons are within an appropriate range. Finally, we propose an energy factor to measure the metabolic demand during neuron firing, and the results show that different energy demands for the normal discharges and the pathological epileptic seizures of the coupled neurons. [ABSTRACT FROM AUTHOR]

Design base shear and lateral force distribution are two important aspects of the seismic design process. Different design methods have been proposed to obtain the design base shear of different types of structures. However, the study related to the lateral force distribution is limited, especially for self-centering (SC) structures. The primary objective of this research is to develop a performance-based seismic design (PBSD) procedure for steel braced frames considering the modified lateral force distribution. Six-story steel braced steel frames are designed to explore the influence of the energy dissipation factor on the lateral force distribution of the frames. Results of nonlinear time-history analyses indicated that the lateral force acting on the roof increases with the decrease in energy dissipation factor. Following the parametric analyses of single-degree-of-freedom (SDOF) systems, the energy factor design spectra are established and the corresponding PBSD procedure for the steel braced frames is proposed. Finally, the four six-story braced steel frames are redesigned using the PBSD procedure with the modified lateral force distribution to illustrate the efficiency of the proposed design method. Analyses results indicate that the steel braced frames designed by the proposed design can satisfy the expected inter-story drift limit with a reasonably uniform distribution of peak inter-story drifts. Furthermore, the 'partial' SC system appears to be a desirable option that effectively controls the residual displacement and peak acceleration responses at the same time, and could achieve a manageable cost control compared to the full SC systems. [Display omitted] • The optimal lateral force distribution of SC and 'partial' SC steel braced frames is investigated. • The energy factor design spectra are established, especially for the 'partial' SC system. • The PBSD procedure considering the modified lateral force distribution for the steel braced frames is proposed. • The 'partial' SC system (e.g., β = 0.75) appears to be a desirable option for the design of steel braced frames. [ABSTRACT FROM AUTHOR]