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

A study on the load characteristics of the modified gear planetary gear systems is conducted to address the issue of uneven loads between planetary gears due to manufacturing and installation errors, which result in deviations between the radial and circumferential installation positions of planetary gears and non-offset values. Based on the theory of rotor dynamics, the time-varying stiffness and the radial and circumferential offsets of the planetary gears are considered, and the five-degree-of-freedom dynamic model of the planetary gear transmission system with addendum modification is established. The response and frequency spectrum of the system are solved by the Runge-Kutta method. The load distribution characteristics of the planet gears under different radial offsets, circumferential offsets, and comprehensive offsets are analyzed. The influence of the radial and circumferential offset of the planetary gear on the load distribution of the planetary gear transmission system is discussed, and the variation law of the load vibration amplitude of the planetary gear transmission system with addendum modification under the time and frequency is obtained. The simulation results show that the load characteristics of the planetary gear train considering the error are quite different from those in theory. Its vibration amplitude of the planetary gear transmission system is greatly affected by the radial offset, and the large radial offset has the greatest impact on the load of the planetary gear. Small deflections of the planetary gear during installation can lead to large changes in the load characteristics. The planetary gear transmission system load test platform is built, the frequency-doubling vibration response signal of the planetary reducer housing is tested, and the relation between the planetary gear transmission system load force and vibration response is obtained. The amplitude variation trend in the experimental results is similar to that in the simulation analysis, and the correctness of the established model and solution method is verified.

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

The difference in power demand and the driver's operation in various operation stages make the loader have the problem of low energy utilization. Changeable operating objects and drastically changing loads have exacerbated the difficulty of energy-saving research in different operating stages of loaders. Therefore, based on identifying the operation stage and analyzing the load characteristics under typical working conditions of the loader, this paper proposes a shovel-loading cooperative control strategy. Specifically, the Drag Reduction Insertion (DRI) in the shoveling stage is realized based on learning the driving intention. Based on different operation stages, the load characteristics of different materials for shovel-loading are deeply analyzed, and the prediction research of the power output characteristics of the power unit is carried out. The shovel-loading cooperative control solves the problem of the poor economy caused by different power requirements in different operation stages and significantly reduces the impact of the driver's operating experience. • A cooperative control strategy for shovel-loading of loader is proposed. • Accurate identification of the operational stages are completed. • The DRI in the shoveling stage is realized based on learning the driving intention. • The prediction research of the power output characteristics of the power unit is carried out. [ABSTRACT FROM AUTHOR]

Under the dual crisis of energy shortage and environmental pollution, natural gas has become a promising alternative fuel. However, its application in marine engines still has some problems such as knocking and misfire in the cylinder, especially during the harsh transient condition of the main engine, which the transient speed regulation rate should be less than 15%, and the speed recovery time should be less than 15s to meet the corresponding specification requirements. In this paper, the 8M23G marine four-stroke natural gas engine is taken as the research object. And, the harsh transient condition of the engine under two modes of load characteristics and propulsion characteristics was analyzed through experiment and simulation. The results showed that the cooperative control strategy had the best effect, which decreased the Lambda of the engine to less than 3.5. Furthermore, the speed recovery time under load characteristics can be controlled at about 10 s. [ABSTRACT FROM AUTHOR]

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

To improve the load characteristics of the transmission error for helical gears, a gear made of laminated materials is proposed. The gear has three layers in which metals with different rigidities are laminated in the tooth width direction. The layers on both sides are made from the same metal, and a different metal is used for the central layer. A theoretical analysis was performed to investigate the effects of arranging high- and low-rigidity layers and changing the width of the central layer. The laminated gear has load characteristics different from the transmission error for a conventional homogeneous material gear. The transmission error can be reduced with the combination of a high-rigidity central layer and a low-rigidity side layers, and a low transmission error can be maintained over a wide load range by adjusting the central layer width appropriately. The principle of the reduction in the transmission error is that, by changing the rigidity along one-pitch meshing progress with laminated materials, the elastic deformation of the teeth can largely cancel out the rotational fluctuations caused by the tooth flank shape over the wide load range. A pair of laminated gears was manufactured, and testing confirmed that the laminated gear has a transmission error lower than that for a gear made from a homogeneous material. The laminated gear has the potential to achieve the lower vibration/noise generation for the wider load range than the homogeneous gear.

Modern power system is stepping into the era of big data. It is necessary to widely collect multi-source data and mine the load characteristics of load data from different angles. This paper introduces an efficient comprehensive characteristic analysis method of 10 kV bus load based on integrated clustering technology, which includes clustering the load from vertical and horizontal dimensions respectively to obtain the clustering results under the unified time frame. Firstly, K-means clustering and hierarchical clustering are used to establish the load characteristic model for the whole year’s load data, and the daily load characteristics and hourly load characteristics are obtained. Then, the distribution time area of the maximum load and the normal operation threshold of the load are analyzed. Finally, the feasibility of this method is verified through the 24 * 365 load data, which provides convenience for the subsequent power system optimization.

This paper aims to analyze the distribution efficiency of DC power distribution power system in commercial building based on measured data from a typical office building in Hong Kong. In this research, a real-scene comparative testbed was built in a Hong Kong office to compare the energy efficiencies of AC and DC power distribution system. Similar load characteristics and use schedules are set and used in the experiment. The distribution efficiency has been found to be affected by load type, voltage level and the loading conditions. The efficiency of this DC power system is derived, considering the PFC model was working in a good condition. For LED loads, the average distribution efficiencies after converter are 77.7% and 51.8 % under the condition of full lightning and normal lightning mode. The main loss in this system is transmission loss and switching loss. The average AC/DC converter efficiencies of LEDs are 92.21% and 88.85% respectively with the load working under full power and normal power, while the average AC power factors of LEDs are 85.31% and 56.22% respectively with the load working under the same as above. The average AC/DC converter efficiencies of the fan coil are 97.41%, 96.03%, 92.74%, 89.10%, 85.71%, 78.72%, 67.61%, 63.57% respectively with the load working under level 8 to level 1 while the average AC power factors of the fan coil are 98.0%, 99.0% and 99.4% respectively with the load working under low middle and high condition. As the PFC circuit does not have ideal power factor correction when the load is small, it is not recommended to add PFC circuit when the load power is low. Using uncontrollable rectifier circuit is going to lead to a better performance.

The load characteristics of a power grid significantly change with the increase in the number of electric vehicles (EVs). In this study, we present a method for predicting the long-term load characteristics of Hubei Power Grid (A large power grid in China with annual power consumption of 207.1 billion kWh in 2020) up to until year 2030 with the development of EVs. The predicted load characteristics include the annual peak loads and hourly load curves of typical days for different seasons in target years 2025, and 2030. The proposed long-term load forecasting method uses saturated load prediction with grey Verhulst model and Monte Carlo simulation. The future impacts of the charging load of EVs on the grid are discussed in detail.

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

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

Industrial steam heating is a significant aspect of energy consumption in China, playing a crucial role in industrial energy efficiency. Historically, demand response research has predominantly focused on the electricity sector, with limited emphasis on steam supply. This study explores a novel Time-of-Use pricing approach for steam heating systems, anchored in the demand response theory of price incentives. It develops a peak-valley segmentation method by considering both the load differences between supply and demand and the thermal storage capacity of the pipeline system. Additionally, the paper delves into user response characteristics to formulate an optimized Time-of-Use pricing model for steam heating systems. Implemented in a Jiangsu-based case study, the model demonstrates significant efficiency improvements: it reduces the peak-valley load difference by up to 68.3% and cuts steam purchasing costs by ¥135,000. Furthermore, the alignment between the users' total steam load curve and the heat source's steam supply is enhanced by 18.8%, illustrating the model's effectiveness in balancing demand and supply. • Cluster analysis to extract steam user load characteristics. • Divide peak/valley times based on network storage and user traits. • Create a multi-objective Time-of-Use model for steam pricing optimization. • Carry out a case validation in an actual industrial park in Jiangsu. [ABSTRACT FROM AUTHOR]

Support insert run-flat tire is a kind of safety tire based on common tire structure. It has the advantages of simple structure, easy disassembly and strong bearing capacity. However, when driving under zero-pressure condition, it can not meet the requirements of heavy load, high mobility and long-distance. Aiming at this problem, the finite element model is established. The load and contact patch characteristics of the model are simulated by ABAQUS. The radial stiffness curve and the contact pressure distribution under zero-pressure are obtained. The results show that the radial stiffness curve presents a certain nonlinearity in the sidewall loading stage. When the insert contacts the tire, it is approximately linear. The contact pressure distribution cloud diagram under zero-pressure condition shows that there is warpage. The tire test bench was set up and the relevant test scheme was formulated. The radial stiffness curve and the footprint of the support insert run-flat tire under zero-pressure condition were obtained. The research results show that the simulation and test results are in good agreement. This research is of great significance to the performance analysis of whole support insert run-flat tire under zero- pressure condition. [ABSTRACT FROM AUTHOR]