bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on adjustable low-frequency sound absorbers based on digital shunt loudspeakers
Authors: Xu Yubing , Cong Chaonan 
Published: May 2024

Abstract
Low-frequency noise is a critical frequency band that affects people’s physical and mental health. Traditional sound absorption technology is limited in effectiveness at low frequencies due to spatial constraints. Shunt loudspeakers, which consist of a loudspeaker connected to a shunt circuit, have emerged as a rapidly developing solution for low-frequency noise control. However, most shunt circuits are implemented using analog circuits, resulting in poor stability and accuracy due to the presence of parasitic resistance. As a result of this situation, this paper proposes an adjustable low-frequency sound absorber based on digital shunt loudspeakers, where the shunt circuit is realized through digital synthetic impedance based on FPGA technology. Additionally, the acoustic impedance can be easily adjusted by the digital shunt circuit without relying on cavity depth adjustments. Experimental results validate that the proposed sound absorber offers excellent performance in adjustable low-frequency sound absorption, thus confirming its theoretical basis.
Ultrasonic cavitation noise extraction based on fence sampling
Authors: Wu Boyue , Tong Haoyang , Chen Yi , Zhao Han 
Published: May 2024

Abstract
The composition of the ultrasonic cavitation sound field is complex, including fundamental, harmonic, subharmonic, super-harmonic, and broadband transient noise. Fundamental waves, harmonics, etc., may interfere with the analysis and research of broadband transient cavitation noise, so it is necessary to filter out these interferences in the sound field. This article conducts measurement experiments on the ultrasonic cavitation sound field generated by high-power ultrasonic cleaning transducers. By utilizing the characteristics of the fence effect, the acoustic signal in the ultrasonic cavitation sound field is resampled through fence sampling so that the fundamental and harmonic components are fused at 0 Hz and filtered out. The ultrasonic cavitation noise is successfully extracted, and its signal structure is the same as the noise component structure in the original signal.
Investigation of dynamic characteristics of hydrofoil with leading-edge tubercles
Authors: Fan Menghao , Sun Zhaocheng , Yu Ran , Li Zengliang 
Published: May 2024

Abstract
The convex structure of a humpback whale flipper is included in the airfoil design to investigate the control principle of the dynamic stall process. The effect of two different types of tubercles on the dynamic stall process of airfoils was investigated. The distribution of dynamic hysteresis loops and pressure fields with streamlines was used to explain the properties of the dynamic flow field and the emergence of dynamic stall vortices. The results demonstrate that the airfoils with tubercles have stronger hysteretic characteristics in the pre-stall region, and the ζ
CM of mod-1 is increased by 51.33%, indicating stronger torsional hydroelastic stability. In the post-stall region, mod-2 is always in a condition of significant flow separation, which impairs the torsional hydrodynamic stability of the airfoil and has the potential to cause flutter. These findings suggest that leading-edge tubercles offer a negligible advantage in reducing airfoil dynamic stall, and their significance warrants further investigation.
Numerical simulation of ice loading characteristics of ships in a wave-current environment in a broken ice area
Authors: Sun Rui , Li Zhifu , Shi Yuyun 
Published: May 2024

Abstract
A numerical simulation technique with CFD-DEM coupling is used to simulate a full-scale KCS model sailing in the pancake ice region. Based on the actual polar information, the Stokes fifth-order wave model is selected. The pancake ice particle of two scales is established based on the DEM, and the corresponding broken-ice region is generated. The contact and collision problems of ice-ice and ice-wall (ship) were analyzed by solving the Hertz-Mindlin model, and the monitored data were processed and summarized. The results show that the ice load on the ship is a repetitive “loading-unloading” process, and the peak ice load curve is characterized by segmented and concentrated fluctuations. In terms of ice parameters, the pancake diameter has a great degree of influence on the crushed ice loads, and the size of the crushed ice loads increases with the diameter of the crushed ice particles.
Calculation and analysis of the transition process of a Francis turbine in a power plant
Authors: Yuan Yang 
Published: May 2024

Abstract
This paper introduces the calculation method and results of the large-fluctuation transition process of the Francis hydro-generator set. The operation of the power station shows that the calculation method and results can meet the engineering requirements, but they cannot reflect the state of the unit during small fluctuations. For large-scale units, this problem needs to be addressed and further research.
Study on two-phase displacement law considering mass transfer and diffusion
Authors: Zhang Lei , Li Aoyang , Sun Hai , Jing Wenlong 
Published: May 2024

Abstract
The influence of channeling on viscous fingering instability of CO2 miscible displacement is studied in the paper. Due to the viscous fingering not easily observed in porous media, channeling is used to simplify the viscous fingering instability. We adopted nonlinear simulation to investigate the development of viscous fingering instability during the displacement of Newtonian fluids in a channel by miscible fluids, and the influence of different Pe and different viscosity ratio R was studied. Under homogeneous conditions, when R is the same, the larger the Pe is, the more obvious the convection in the process of CO2 displacement is, the earlier the viscous fingering occurs, and the shorter the time for the finger to break through to the right boundary is. When Pe is the same, the larger the R is, the more unstable the contact area of miscible displacement becomes. More finger structures appear, and more complex fingering phenomena occur. The larger the R is, the earlier the fingering phenomenon appears, and the earlier it breaks through to the right boundary. In addition, we studied the change in Relative Mixing Length (RML) during the diffusion process quantitatively. Finally, our investigation delved into the impact of heterogeneity on viscous fingering. We observed that under significant heterogeneity, viscous fingering tends to manifest preferentially in the direction of increasing permeability.
Aggregate scheduling potential evaluation of large-scale air conditioning loads
Authors: Huang Hui , Gao Yun , Wang Song , Li Shun , Wu Fuzhang , Zhu Bin , Long Yi 
Published: May 2024

Abstract
As an adjustable load, the air conditioning (AC) load is a high-quality resource for power system operation regulation. However, due to the large number of AC loads and the heterogeneity among individual users, the scheduling potential of AC loads is difficult to accurately calculate. An aggregate scheduling potential evaluation of large-scale AC loads is proposed. Firstly, according to the operation characteristics of ACs, the aggregation models of central ACs and household split-type ACs are constructed by using the equivalent thermal parameter model and Monte Carlo sampling method respectively. Secondly, based on the proposed aggregation models of large-scale AC loads, the AC loads are rescheduled by resetting the set temperature, and the scheduling potential calculation model of central ACs and residential ACs is obtained. Finally, case studies show that AC loads have considerable scheduling potential when the indoor temperature is maintained within the range of human comfort.
Selection and integration of adjustable load in multiple scenarios
Authors: Zhou Zhaozheng , Ye Wei , Leng Zhenglong 
Published: May 2024

Abstract
In the context of the “carbon peaking and carbon neutrality goals”, the new electricity systems are evolving towards source-load friendly interactions. At the same time, the increasing necessity for adjustable loads to participate in the power balance of the new electricity systems is highlighted. Consequently, a large-scale source-grid-load design scheme is proposed. It employs three independent communication channels to facilitate communication between users and intelligent grid-load terminals. Based on analysis of the individual loads and equipment characteristics of each user, principles for user shunt load access principle and adjustable loads are formulated by combining the maximum duration, frequency constraints, and compliance costs. Furthermore, it proposes construction plans for both the customer side in a single distribution room and the customer side distributed across different locations. According to the experimental analysis of 245 users, the response time of the experimental system is less than 600 ms. These advancements enhance the emergency response speed and responsiveness, contributing to the advancement of precise, real-time, and lean management of the demand side of the power grid.
Study on the error characteristics of transformer for primary and secondary fusion used in pole-mounted switchgear
Authors: Xia Lingyu , Wu Xixiu , Hou Hui , Wu Shipu , Peng Yunbing , Cao Jiaxin 
Published: May 2024

Abstract
The fusion of primary and secondary functions refers to integrating the function of primary equipment and secondary equipment together. If doing so, the working condition of the equipment for primary and secondary fusion becomes more and more complex and bad, especially the transformer working in the smaller workspace after fusing. Therefore, this paper focuses on the transformer used in primary and secondary fusion pole-mounted Switchgear and establishes the temperature field and electric field simulation model of the primary and secondary fusion pole-mounted switchgear transformer, respectively, and the temperature rise and the environment electric field interference influencing the error of transformer are analyzed as well. When the working environment temperature ranges from -40 to 70°C, the maximum error of low-power current transformers and resistive voltage transformers is 0.1246% and 0.0371%, respectively. The electric field is one of the main factors influencing resistive voltage transformers, which makes ratio errors and angle errors -0.256% and -22.5392’, respectively. The research reveals that under conditions, the error is mainly dependent on temperature rise and electric field. These two factors have a great influence on the error, while the transformers still have enough reliability.
A method of distributed series compensation for low voltage management in power distribution network
Authors: Zhao Zhiyu , Wang Yajuan , Liang Weichen , Jiang Xin , Liu Bo , Ma Xinsheng , Li Xuan 
Published: May 2024

Abstract
In some areas with sparse populations and dispersed power loads, the construction investment of distribution network lines cannot keep up, and the phenomenon of low voltage at the end of the power distribution network is particularly serious, even causing some household appliances to be unable to start. This article aims to provide some solutions to alleviate the low voltage of distribution network lines in certain regions. It introduces a method based on distributed series compensation for long lines with low voltage of the line terminal. In the same distribution network line, it is installed two or more sets of series compensators to alleviate the low voltage problem at the end of the long line of the distribution network based on a decentralized arrangement. The technical scheme is based on a 10 kV feeder for simulation to verify the correctness and effectiveness of the proposed method.
Data-driven battery health state estimation based on charging and switching cabinets
Authors: Zhang Yong , Liu Jingwei , Zhen Jiuguo , Qiao Zhenjia 
Published: May 2024

Abstract
Accurate evaluation of the battery’s state of health (SOH) in the charging and switching cabinet is crucial to ensure the battery operates safely and reliably, while also reducing maintenance costs for the battery system. A support vector regression technique, utilising the sparrow algorithm optimisation, is suggested to improve the precision of assessing the battery’s state of health in the charging and switching cabinet. This algorithm tackles the task of identifying parameters in the conventional model. Analysing the ageing dataset of lithium batteries is the initial stage to determine the health parameters that signal the battery’s health state. The support vector machine regression algorithm is employed to select the kernel function and penalty factor, which are fine-tuned using the sparrow optimisation technique. The data is utilised to create the SSA-SVR model. The battery health status of the charging and switching cabinet is assessed. The study shows that the enhanced support vector regression model can effectively monitor the status of lithium-ion batteries and achieve superior estimation results for different types of batteries.
Prediction of power generation output of compressed air energy storage tank based on temperature limitation
Authors: Wen Xiankui , Wu Yinghao , Zhang Junwei , Zhang Shihai , Wu Chao 
Published: May 2024

Abstract
The pressure and temperature of the CAES system drop during the power generation process. This generation will be forced to stop when the temperature reaches the metal material limit. To avert the power generation process from stopping due to the temperature dropping too low, it is necessary to monitor and predict the power output of the CAES system in real time. By setting the relevant control operation logic, according to the temperature limit value of the gas canister, the minimum allowable temperature of the gas canister design, and the maximum value of the minimum allowable temperature of the pipe design between the gas canister and the heat exchanger, the minimum allowable temperature of the gas canister is obtained. the residual energy release energy and residual energy release time of the gas storage tank can be calculated by collecting relevant parameters in real time. It is verified by the simulation experiment of the 10 MW CAES system model. By monitoring the changes in parameters such as the temperature of the gas canister during the energy release process, the prediction model can calculate the compressed gas in the gas canister more accurately, and the power generation output can be predicted in the operation of the CASE system. Mastering the residual energy release energy and residual energy release time of the gas canister can arrange the operation mode in advance and improve the reliability of unit operation.
Direct power control of dual three-phase permanent magnet synchronous motor based on multiple vectors
Authors: Pei Yuanxin , Zhi Pengfei , Wei Haifeng , Zhang Yi 
Published: May 2024

Abstract
In response to the traditional mode of dual three-phase permanent magnet synchronous generator switch form vector direct power control (DPC), the current harmonics are large, the active (P) and reactive (Q) harmonic oscillations are large, and the unstable losses of each phase current are large. A virtual voltage vector direct power control method based on duty cycle modulation is proposed. This method compares and synthesizes the two vectors of the outermost and second layers of the PWM rectifier, as well as three large vector synthesis methods, to obtain 12 new virtual voltage vectors. Then, the combined voltage vector is directly modulated into the deadbeat switching table, and the optimal predicted vector value is calculated based on the principle of the deadbeat formula, further suppressing the problem of large fluctuations in active and reactive power. Results show that the proposed multi-vector composite odd even quadrant DPC can effectively reduce current harmonics and power ripple, make the phase current more stable, reduce motor operating losses, and significantly improve the motor.
LLC resonant converter analysis in PO mode
Authors: Mao Wenlong , Ma Xiaosan 
Published: May 2024

Abstract
The PO mode under time-domain analysis is a kind of discontinuous conduction mode (DCM) which is beneficial to reduce the switching loss of the converter, but the calculation of the gain and frequency characteristics of the converter in this mode is cumbersome and difficult to be solved. Based on the analysis method of time domain approximation, the PO operating mode characteristics of the LLC resonant converter are analyzed, and a simple and accurate voltage gain calculation formula is theoretically deduced. Simple analytical expressions for the PO mode power boundary conditions are given based on the voltage variations of the magnetizing inductance and capacitance. A simulation model of the studied converter is established, and the simulation can prove that the proposed voltage gain formula and PO mode boundary conditions are correct.
Shore Power System Load Forecasting Model based on IDBO algorithm and PCA-BiLSTM Network
Authors: Gu Shuangnan , Yang Yayu , Shi Wenchao , Tong Jijian 
Published: May 2024

Abstract
Shore power offers convenient and sustainable power services to ships docking in ports, playing a pivotal role in advancing environmental preservation and the effective utilization of resources. Shore power system loads are susceptible to numerous influencing factors. Therefore, it is crucial to identify a highly accurate load forecasting model to facilitate the judicious allocation of power resources. A short-term shore power system load forecasting model based on the improved dung beetle optimization algorithm (IDBO) and principal component analysis (PCA) in conjunction with the enhanced bidirectional long and short-term memory (BiLSTM) network is proposed in this paper. The IDBO algorithm improves the problem of low convergence accuracy and vulnerability to local optima in DBO. This is achieved by population initialization based on cubic chaotic mapping, amalgamating walrus optimization algorithm, and adaptive t-distribution perturbation strategy. The performance of the BiLSTM, IDBO-BiLSTM, and PCA-IDBO-BiLSTM shore power system load forecasting models are compared through case studies, revealing that the proposed PCA-IDBO-BiLSTM model demonstrates superior predictive capabilities.
A novel approach for disentangling packed peaks in the energy spectrum of γ detector arrays through γ-γ coincidence analysis
Authors: Xu Yingfeng , Wang Shitao 
Published: May 2024

Abstract
A novel approach has been proposed to effectively separate cascaded and closely packed full energy peaks in the energy spectrum of γ detector arrays. By conducting a sequence of γ-γ coincidence analyses on the energy spectrum, it is feasible to obtain a spectrum that represents the product of these packed peaks. We have designated the newly obtained spectrum as the “product spectrum”. The energy spectrum and the newly obtained product spectrum can be simultaneously fitted, enabling a more precise fitting and separation of the closely packed peaks. This method has been mathematically proven, and validated through the use of Monte Carlo simulation. The systematic errors of this method are also taken into consideration.
Modelling future coastal water pollution: impacts of point sources, socio-economic developments & multiple pollutants
Authors: Bak Mirjam P , Kroeze Carolien , Janssen Annette B G , Strokal Maryna 
Published: May 2024

Abstract
Urbanisation is happening worldwide. In 2100, over 70% of the population is projected to live in highly urbanised areas. As a result, urban wastewater discharge may increase. This may add multiple pollutants to rivers and coastal waters. However, current knowledge on how urbanisation-related socio-economic developments affect coastal water pollution is limited. In this study, we analysed individual and combined impacts of wastewater treatment improvements, economic growth and city expansion on future coastal water pollution from point sources (sewage and open defecation) by sub-basin taking a multi-pollutant approach. We improved the existing MARINA-Multi model (version Global-1.0) by integrating hydrology and pollutant retentions in order to quantify river exports of total dissolved nitrogen, total dissolved phosphorus, microplastics and triclosan to coastal waters for 2010 and 2100 using scenario analysis. Globally, river exports from point sources are projected to more than double by 2100 for all pollutants, especially in Africa and Asia. Wastewater treatment improvements, economic growth and city expansion can have a positive (less pollution) or negative (more pollution) impact on future coastal water pollution. These impacts differ among pollutants and sub-basins. Wastewater treatment improvements may globally reduce multi-pollutant issues (−30% to −38% change on average) compared to the reference scenario (positive impact). Economic growth and city expansion may globally enhance multi-pollutant issues (+15% to +25% and +28% to +33% change on average, respectively) compared to the reference scenario (negative impact). A combined scenario, accounting for all three socio-economic developments simultaneously, may globally reduce or enhance pollutant issues (−21% to +50% change on average) compared to the reference scenario. In the combined scenario, the reinforcements of positive and negative impacts are pollutant- and region-dependent. Our study gives insights into future coastal water pollution, which aids in identifying management strategies for urban areas, hence contributing to reaching Sustainable Development Goal 14.
Coated boron layers by boronization and a real-time boron coating using an impurity powder dropper in the LHD
Authors: ASHIKAWA Naoko , LUNSFORD Robert , NESPOLI Federico , GILSON Erik , YU Yaowei , HU Jiansheng , KADO Shinichiro 
Published: May 2024

Abstract
In the Large Helical Device (LHD), diborane (B2H6) is used as a standard boron source for boronization, which is assisted by helium glow discharges. In 2019, a new Impurity Powder Dropper (IPD) system was installed and is under evaluation as a real-time wall conditioning technique. In the LHD, which is a large-sized heliotron device, an additional helium (He) glow discharge cleaning (GDC) after boronization was operated for a reduction in hydrogen recycling from the coated boron layers. This operational time of 3 h was determined by spectroscopic data during glow discharges. A flat hydrogen profile is obtained on the top surface of the coated boron on the specimen exposed to boronization. The results suggest a reduction in hydrogen at the top surface by He-GDC. Trapped oxygen in coated boron was obtained by boronization, and the coated boron, which has boron-oxide, on the first wall by B-IPD was also shown. Considering the difference in coating areas between B2H6 boronization and B-IPD operation, it would be most effective to use the IPD and B2H6 boronization coating together for optimized wall conditioning.