bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time-evolving Impact of Trees on Street Canyon Microclimate
Authors: Li Haiwei , Zhao Yongling , Bardhan Ronita , Kubilay Aytac , Derome Dominique , Carmeliet Jan 
Published: December 2023

Abstract
Nowadays, cities are frequently exposed to heatwaves, worsening outdoor thermal comfort and increasing cooling energy demand in summer. Urban forestry is seen as one of the viable and preferable solutions to combat extreme heat events and urban heat island (UHI) in times of climate change. While many cities have initiated tree-planting programs in recent years, the evolving impact of trees on street microclimate, in a time span of up to several decades, remains unclear. This study focuses on the cooling effects of a common type of street trees, linden trees, in five age groups, i.e., 10-20, 20-30, 30-40, 40-60, and 60-100 years old, while the diversity of trees is present in nature, that is, various species and crown geometries, The leaf area index (LAI) and leaf area density (LAD) of linden trees vary nonlinearly as they grow, peaking at different ages. Computational fluid dynamics (CFD) simulations were performed for an idealized street canyon with linden trees of various age groups. Turbulent airflow, heat and moisture transport, shortwave and longwave radiation, shading, and transpiration were fully coupled and solved in OpenFOAM. Meteorological data, including air temperature, wind speed, moisture, and shortwave radiation of the heatwave in Zurich (June 2019), were applied as boundary conditions. The results show that young trees in the age group of 10-20 years old provide little heat mitigation at the pedestrian level in an extreme heat event. Optimal heat mitigation by trees is observed for the group of 30-60 years old linden trees. Finally, the potential impact of growing trees on air ventilation in streets is evaluated.
Improved mesoscopic meteorological modelling of the urban climate for building physics applications
Authors: Strebel D , Derome D , Kubilay A , Carmeliet J 
Published: December 2023

Abstract
A meteorological mesoscale model is used to predict the local urban climate at 250 m resolution. The authors propose a hybrid machine learning approach to improve the prediction accuracy and remove simulation bias. Two case studies are presented to show the improvements of the simulation accuracy. Based on the hybrid model results, using cooling degree hours is proposed as an insightful time-dependent index to map local hotspots and assess the difference of cooling loads between rural and urban environments.
Multi-agent Cooperative Optimization Strategy of a Virtual Power Plant Based on Game Theory
Authors: Hong Huawei , Yu Xian 
Published: December 2023

Abstract
This paper proposes a multi-agent collaborative optimization method for virtual power plants based on the Bayesian game. Focusing on the internal scheduling of VPP, taking demand response load as the analysis object, aiming at the interactive optimization relationship between multiple intelligent communities in the virtual power plant under this scenario, a multi-agent collaborative optimization model of the virtual power plant is established by using Bayesian game theory. The effectiveness of the constructed game model and algorithm is verified by solving the actual example of the virtual power plant and analyzing the corresponding simulation results.
Improving the Success Rate of Electricity Information Collection System
Authors: Kang Liyan , Liao Liying , Qin Yuewei 
Published: December 2023

Abstract
The electricity information collection system built in China is the world’s largest user-side data collection, monitoring, and control system. With a total coverage of 540 million electricity users, it has played an important role in the safety production and operation management of the power system. The success rate of data collection in the collection system is an important indicator to measure the quality of system operation. This article analyzes and studies the factors that affect the success rate of collection from the dimensions of the main station, channel, terminal, meter, and synthesis. It provides a large amount of experimental and test data and thus obtains methods to improve the success rate of collection. It provides reference and improvement methods for the construction of power system information engineering.
Experimental study on electric fire based on nitrogen injection technology
Authors: Kuai Shichao , Li Ningning , Zheng Wei , Tong Jingguang , Zhao Feng , Xu Lei , Qi Zibo 
Published: December 2023

Abstract
Electric fire occurs frequently in daily life. The fault arc, overload and short circuit of electric fire phenomena are the important factors of electric fire. In view of this, electric fire test research based on nitrogen injection technology is carried out, focusing on the effect of nitrogen injection technology on fault arc, overload, and short circuits of electric fires. The combustion inhibition characteristics of nitrogen injection technology on electric fires are analyzed through comparative tests, and the application method of nitrogen injection technology in the field of electric fire prevention is explored.
New Topology Design and On-line Charging and Discharging Technology of Substation DC System
Authors: Zhu Minjie , Tang Yiqin , Le Xubo , Zhang Bingye , Su Xingyang , Zou Guoping 
Published: December 2023

Abstract
The substation DC system uses battery packs as a backup power source. It needs to be regularly checked for capacity. In the existing topology, batteries are connected in series as a power source. When checking capacity discharge, an additional backup power supply must be built to replace it, which is costly and complicated to operate. To this end, this paper proposes a new battery topology. The previous 54 series batteries were divided into 3 packs, with each consisting of 18 batteries. The three battery packs are connected in parallel to the DC bus through bidirectional DC/DC converters. The automatic charging and discharging control strategies of the battery packs under the new topology are studied. The system can automatically charge and discharge batteries through bidirectional DC/DC converters, and conduct online capacity testing of battery packs. Simulation results show that the designed new topology not only realizes the online verification of battery capacity but also saves the test cost. The power supply reliability of the DC system of the substation is also greatly improved through the redundant structure.
Security Analysis of Distribution Network Loop Closure Based on Half Invariant Method
Authors: Xu Zhiguang , Chen Dongxu , Chen Shengshuo , Kang Shijia , Li Yansong , Liu Jun 
Published: December 2023

Abstract
The integration of distributed power sources requires active power systems to raise new concerns about their safety. In order to scientifically and effectively analyze the safety of active distribution network closing current, taking photovoltaic power supply as an example, a closed-loop equivalent model considering the influence of distributed power sources was proposed, and an equation based on the random fluctuation current of new energy sources was derived. On this basis, a semi invariant method is used to solve the random fluctuation variable of the required current, and corresponding indicators are developed based on the principle of closed loop safety to evaluate the safety of the closed loop current. Based on PSCAD and MATLAB platforms, simulation calculations were conducted, and the simulation and calculation values were compared to verify the feasibility and timeliness of the closed-loop security analysis model based on the semi invariant method.
Feeder Capacity Planning and Reliability Evaluation Model of Distribution Network Based on Support Vector Machine
Authors: Yin Xiang , Liu Yan , Wu Chaoqun , Li Xing 
Published: December 2023

Abstract
Capacity planning and reliability evaluation models of the traditional distribution network feeder mainly use multi-option balance constraints for multi-objective solutions, which are prone to capacity constraints, resulting in lower reliability indicators for planning and evaluation. Therefore, a brand-new distribution network feeder capacity planning and reliability evaluation model based on a support vector machine is designed. By using support vector machines to design the reliability evaluation process of distribution network feeder capacity planning, we establish an optimization model for reliability evaluation of distribution network feeder capacity planning. The experimental results show that the designed feeder capacity planning and reliability evaluation model based on a support vector machine has good evaluation results, high-reliability indicators for planning and evaluation, reliability, and certain application values.
Fault Location and Phase Selection Method of Distribution Network Containing IIDG Based on Online Active Detection
Authors: Cheng Yunxiang , Liu Xiangbo , Wang Sen , Gao Fang , Li Hao , Yu Chengao , Tao Zhengchen 
Published: December 2023

Abstract
This paper proposes a fault location and phase selection method for the distribution network containing IIDG based on online active detection, utilizing online active detection. In this method, the characteristic harmonic current injection control strategy based on d- and q-axis control is obtained by analyzing the structure, control strategy, and short-circuit current of IIDG. During a fault, the distributed power supply injects characteristic harmonic current into line, adapting its magnitude with the short-circuit current’s size. By detecting the difference in harmonic current content rate for both ends of the fault point, the method achieves online location and line selection of fault points. A 10 kV IIDG distribution network model is simulated by using PSCAD to validate the feasibility and accuracy of the proposed fault location and phase selection method.
Simulation and Generation of the In-born Strong Magnetic Environment During Railgun Launch
Authors: Cao Genrong , Qiao Zhiming , Liang Chunyan , Yuan Xichao , Xiang Hongjun 
Published: December 2023

Abstract
The in-born strong magnetic environment during the launch process of the railgun is a potential risk for ammunition applications. Currently, there are no mature means to simulate the magnetic field environment to provide a platform for the electromagnetic safety test of ammunition. Given this problem, a strong magnetic environment generation system was designed. By establishing the theoretical model of the magnetic field generated, the difficulty of generating specific waveforms of strong magnetic fields was broken through. Besides, the strong magnetic field generator’s multi-physical field response was analyzed by using the FEM method, and its stability of structure and temperature was evaluated. Finally, the strong magnetic environment generation experiment was conducted, where the in-born magnetic field during the launch process of the railgun was generated successfully. As a result, the strong magnetic environment generation system can generate the expected strong magnetic fields. The magnetic flux density is 10 T, and the pulse width is 6.1 ms.
Studies of the effect of preset square pores on the mechanical properties of Ag nanopsheets under biaxial stretching
Authors: Qin Muyang , Zhang Yanan , Yang Qinyou 
Published: December 2023

Abstract
This study investigated the mechanical properties of silver nanosheets with preset square pores regarding energy, natural strain, and stress properties. Additionally, the effect of different pore positions on dislocations under symmetrical and asymmetrical loading was analyzed using a model of silver nanosheets with square pores preset under biaxial stretching and molecular dynamics methods. The results revealed that the interaction between shear stress and dislocation can cause fractures, with greater shear stress observed when the pore is closer to the model boundaries. Moreover, the symmetrically positioned pores displayed different mechanical properties under asymmetric loading.
A Compact Split-step Finite Difference Method for Solving the Nonlinear Schrödinger Equation
Authors: Nizam Elminur , Rahman Kaysar 
Published: December 2023

Abstract
The nonlinear Schrödinger equation arises from quantum mechanics and is extensively used in many fields of science and engineering. Thus, it is important to construct the high-order and stable numerical scheme of the Schrödinger equation. To solve the high-order and stable numerical solution of the nonlinear Schrödinger equation, the compact split-step finite difference method and the local one-dimensional method are combined in this paper. To attain high-order accuracy in time and space, the 4-order compact finite difference in space discretization is combined with the L-stable Simpson method in time discretization. Therefore, a scheme with 4-order accuracy in space and 3-order accuracy in time is obtained, and the stability of the scheme is analyzed. Finally, numerical results manifest that the devised scheme can supply accurate and stable results to the nonlinear Schrödinger equation.
Mixed Direct Discontinuous Galerkin Method for the Biharmonic Equation
Authors: Wang Huanhuan 
Published: December 2023

Abstract
In this paper, we use the mixed direct discontinuous Galerkin method (DDG) to solve the biharmonic equation. Firstly, by introducing an auxiliary variable, the biharmonic equation is split into two second-order equations. Secondly, the variational problem based on the DDG method of the system is derived and its well-posedness is proven. Next, error estimates of the approximate solution in L
2 norm and energy norm are present. For a given polynomial degree k (k ≥ 1), the optimal convergence rates concerning energy norm and norm are k and k + 1, respectively. Finally, numerical results demonstrate the accuracy and capability of the method.
Bounds for the spectral radius of Schur product of matrices
Authors: Zhong Qin 
Published: December 2023

Abstract
We establish a new upper bound on the spectral radius for the Schur product of two matrices with nonnegative elements by utilizing the eigenvalue inclusion theorem. The new bound is more useful in practical applications because it is simply based on the elements of two matrices. Additionally, a numerical example is taken into account to show that, in some circumstances, the result achieved is superior to some previously reported results.
Simulation Analysis and Lightweight Design of Automotive Transmission Shafts Based on Optistruct
Authors: Zeng Wenhao , Mao Luyao , Huang Dong , Wang Can , Chen Qiyu 
Published: December 2023

Abstract
The transmission shaft is an important power transmission assembly in the automotive transmission system. Its structural mechanical performance is crucial for the comfort and safety of the vehicle. For this purpose, the transmission shaft of commercial vehicles is taken as the research object. Mechanical simulation analysis is conducted based on the finite element analysis software of Optistruct to investigate the stress and displacement distribution of various components on the transmission shaft under maximum torque and to verify its strength and stiffness. In addition, based on the stress distribution and manufacturing process requirements of the transmission shaft, a lightweight design is carried out for the transmission shaft components. The research results indicate that using simulation analysis methods can quickly obtain the force transmission path of the transmission shaft assembly and introducing manufacturing process requirements for lightweight design not only meets the manufacturing requirements but also has a more uniform stress distribution. The overall structure of the transmission shaft has been reduced from 23.8 kg to 16.8 kg with a weight reduction of 30%. The lightweight design method described in this article can quickly achieve weight reduction goals while meeting the structural strength of the transmission shaft.
The correlation between static strength and fatigue strength test and simulation
Authors: Miao Chenglin , Wang Hao , Song Ye 
Published: December 2023

Abstract
In the bogie, the frame plays a vital role. It is not only the installation foundation and direct bearing structure of other components but also can transmit the excitation load from all directions. Therefore, the rationality and reliability of the frame design are particularly critical. In this work, according to EN13749, UIC615-4, JIS E 4207, and JIS E 4208 standards, the load conditions are compiled, and the finite element analysis is carried out. The static strength and fatigue strength are tested on the test bench. The results show that the static strength results of the bogie frame are less than the allowable stress of the corresponding material. The fatigue assessment was carried out by Goodman diagram, and the data all fell within the envelope, which met the requirements of fatigue assessment. Finally, the test results are compared with the simulation results. Through the correlation analysis of the static strength test results and the finite element simulation results of the frame, the stress exceeds 10% of the material yield limit under the exceptional load condition, and the large stress points of the local hanger are compared. The results show that the frame strength test results and the finite element simulation results maintain a good correlation.
Evaluation of Gradation and Stress State Effects on the Resilient Modulus of Crushed Aggregate Materials
Authors: Wei Aozhong , Sun Jiaqian , Li Cheng , Bu Shanshan , Wang Weiwei , Xiang Wen 
Published: December 2023

Abstract
Resilient modulus is a key mechanical parameter for unbound granular base materials. To evaluate gradation effects on the resilient modulus of crushed aggregate materials, the present study conducted laboratory resilient modulus tests on two categories of crushed aggregate materials with seven different gradations. A multi-factor sensitivity analysis was performed on test results and found that the confining pressure and axial stress yield a more significant impact on resilient modulus than the gradation. Different material gradations can yield an average impact of 8%, with a maximum of 21%, and show increased sensitivity with aggregate gradation becoming finer.
The study on the influence of different damage introduction methods on the damage characteristics of aircraft composites
Authors: Zhang Yao 
Published: December 2023

Abstract
Composite materials have advantages incomparable to traditional metal materials. However, they are more sensitive to impact damage and their mechanical properties decrease significantly after impact damage. Therefore, it is of great significance to study the energy absorption, mechanical response and damage mechanism of materials in different ways. To study the influence of different punch diameter sizes on the material damage characteristics, three kinds of punch diameters of 12.7 mm, 16 mm and 25.4 mm are selected to carry out the quasistatic indentation test and drop hammer impact damage test on the test pieces respectively. The material damage caused by different punch sizes under two damage introduction methods is analyzed. Damage introduction was carried out on the test piece with the same layering through two methods: quasi-static indentation and drop hammer impact. The damage depth, damage area and residual strength were compared after damage introduction. The difference between quasistatic indentation and drop hammer impact damage introduction was verified by comparing the damage characteristics to each other. The results show that with the increase of punch diameter size, the damage area decreases and the residual strength of the material increases. In addition, the test results of different punch diameter sizes under the two damage introduction methods have the same change trend, which proves that the impact of punch size on the material damage characteristics has no obvious relationship with the damage introduction method. Quasi-static indentation and drop hammer impact damage have no significant difference in the residual strength of materials after damage, which verifies the equivalence of static indentation and damage introduction.
Flexible Adaptive Integrated Compensation Strategy for Voltage Sag
Authors: Li Baojuan , Shang Fangbin , Wang Renzheng , Wu Xiaojie , Fan Di 
Published: December 2023

Abstract
A dynamic voltage restorer (DVR) is often used for voltage compensation to reduce or eliminate the harm of voltage sag. The existing combined compensation strategy does not consider the specific process of voltage sag, so it cannot adapt to the change according to the drop depth and eliminate the phase abrupt change. In this paper, a flexible, adaptive combination compensation strategy is proposed, which adopts the appropriate compensation strategy according to the actual voltage change process, sets the transition period to avoid phase jump, and adopts the full voltage compensation strategy to fully recover the phase at the end of the voltage dip, to realize the adaptive, flexible compensation of voltage. The simulation results show that the compensation strategy varies with the voltage drop depth. Both the intermediate phase fluctuation and the energy consumption are smaller. The final compensation is complete.
Control Strategy of Three-level Active Neutral Point Clamped Grid Connected Inverters in Unbalanced Power Grid
Authors: Chen Yuwei , Guo Kunli , Bai Yang 
Published: December 2023

Abstract
Traditional phase-locked loops in three-level active neutral point-clamped inverter grid-connected systems for photovoltaic power generation exhibit a deficiency in the decoupling of positive and negative sequences under unbalanced power grid conditions. To address this issue, this study proposes the implementation of the fourth-order generalized integrator into the phase-locked loop to facilitate positive and negative sequence decoupling. Initially, a 3L-ANPC inverter grid connection system is established. However, under unbalanced grid voltage conditions, the PLL effect of the Decoupled Double Synchronous Reference Frame Phase-Locked Loop is found to be suboptimal, leading to considerable fluctuations and distortions in the output frequency signal. To address these complications, we propose an optimized phase-locked loop structure. In this improved design, the PLL first utilizes the FOGI to filter out multiple harmonics in the grid voltage prior to decoupling the positive and negative sequence voltage. This process effectively mitigates the effect on the PLL, thereby enabling rapid and precise tracking of the grid voltage. Simulation analysis is conducted by using Matlab/Simulink to substantiate the effectiveness of the proposed PLL, demonstrating its ability to reliably lock onto the frequency and phase of the fundamental voltage under conditions of unbalanced power grid voltage.
Estimation of Battery State of Charge Based on Electrochemical Impedance Spectroscopy and Machine Learning
Authors: Guo Dongliang , Guo Pengyu , Sun Lei 
Published: December 2023

Abstract
With the increasing application of lithium-ion batteries in energy storage (ES) and electric vehicles (EV), the operation state and the safety early warning are particularly important. Due to the complexity of lithium-ion batteries, predicting the state of charge (SOC) of batteries is still a great challenge. In this paper, an electrochemical impedance spectroscopy (EIS) based on the SOC estimation method was proposed. The EIS of different SOC under 25℃ was measured, and the variation characteristics of EIS were summarized from the aspects of amplitude and phase by using the full band information. Finally, the linear system and BP neural network model were constructed by selecting the characteristic parameters at a specific frequency. The results demonstrate that the prediction effect of the BP neural network is better, and the error is found to be less than 3%.