bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radar and communication integration under FPGA platform: real-time waveform generation with time division multiplexing and waveform sharing strategy
Authors: Jia Guowen , Zhang Zhen , Tang Yiwen , Zhang Yue 
Published: December 2024

Abstract
The integration of radar and communication technologies is gaining prominence in electronic information systems. This paper explores advanced waveform strategies—LFM (Linear Frequency Modulation) + MSK (Minimum Shift Keying) based on time-division multiplexing and LFM-MSK utilizing waveform sharing. These methods enhance spectrum efficiency and system capabilities in detecting targets and transmitting data reliably amidst complex environments. Based on the FPGA (Field Programmable Gate Array) platform, this study proposes real-time waveform generation methods for integrated radar communication waveforms, specifically LFM+MSK and LFM-MSK. It focuses on discussing FPGA implementation solutions for these methods and validates their effectiveness. This research addresses a critical gap in the field and provides practical insights for radar communication integration systems.
Construction and identification of defect knowledge map for DC protection system
Authors: Yao Tao , Zhang Lie , Wang Ye , Ren Xuchao 
Published: December 2024

Abstract
With the continuous acceleration of DC engineering construction, the equipment scale of the DC protection system continues to expand. As the core part of DC transmission, the DC protection system has become an important factor affecting the safe and stable operation of the power grid. The diagnosis and handling of defects in DC protection system equipment often rely on expert experience and technical service support from manufacturers, making it difficult to detect and handle them in a timely manner. Defect analysis and handling are time-consuming and labour-intensive, and disposal experience cannot be shared, posing hidden dangers to the safe and stable operation of the power grid. The DC protection system contains a massive number of components and has extremely complex internal logic. Traditional data mining methods make it difficult to fully extract the semantic features of defect texts in DC protection devices. Therefore, this paper analyzes the types and causes of protection devices in DC transmission systems, uses the Word2Vec-Bootstrapping algorithm to extract the DC protection defect knowledge, uses the Bootstrapping algorithm to classify the word relation, and proposes a modeling method of DC protection device defect Knowledge map. By converting the extracted knowledge into triplet form and constructing a knowledge map, the causes and treatment measures of DC protection defects are diagnosed. An example shows that this method can fully extract the semantic features in the DC protection device defect record text, improve the utilization rate of the defect text record, and accurately identify the defect of the DC protection device.
Wide-range ZVS control technology of bidirectional dual-bridge series resonant DC/DC converters based on phase-shift frequency modulation control
Authors: Ye Yujie , Wang Fusheng , Wu Huijie , Cheng Shuai 
Published: December 2024

Abstract
Increasing the switching frequency helps optimize the performance of resonant DC-DC converters and reduces the size of resonant components, but it also increases the switching losses. To address the challenge of achieving soft switching in the medium to low power range, this paper proposes a new control strategy. In this paper, it achieves a wide range of Zero Voltage Switching (ZVS). It combines Variable Frequency Modulation (VFM) and Phase Shift Modulation (PSM), utilizing Minimum Current Trajectory (MCT) control to reduce the system’s conduction losses. Besides, VFM is used to extend the ZVS range and reduce switching losses.
Kinematics modeling and analysis of large parabolic cylindrical deployable antenna support mechanism
Authors: Fu Linhan , Chen Jinbao , Chen Chuanzhi , Zhang Yingxue , Song Zhicheng 
Published: December 2024

Abstract
A high deployment ratio, large aperture, lightweight design, and high precision are the trends in the development of future deployable antennas. To meet the mission requirements of spaceborne antennas, a large parabolic cylindrical deployable antenna support mechanism composed of multiple rectangular modules is constructed, and a kinematic modeling method for multi-module linkage is proposed. Based on the structure and deployment principles of the antenna, a spatial geometric model of the antenna support mechanism is constructed. By integrating the Denavit-Hartenberg (D-H) method and robotics theory, kinematic models for both the basic deployment unit and the overall mechanism are established. Finally, the models are validated and analyzed through geometric modeling and numerical simulation. The results show that this configuration design can fit different parabolic curves by adjusting the parameters of the rods and can be extended to a scale of hundreds of meters. Meanwhile, the accuracy and reliability of the kinematic models for both the basic deployment unit and the overall mechanism provide a theoretical foundation for subsequent dynamic studies and systematic optimization of the antenna support mechanism.
Design of optimal sliding mode control system for PMLSM
Authors: Zhu Chuanmin , Wang Dawei , Li Zhiyuan 
Published: December 2024

Abstract
To enhance the responsiveness and resilience against disturbances in the speed regulation system of Permanent Magnet Linear Synchronous Motors (PMLSM), an advanced control approach leveraging optimized sliding mode control is introduced. Initially, a foundation is laid by designing a PI-based speed control system and a conventional sliding mode control system within the framework of PMLSM vector control. Simulation models are then constructed to validate the efficacy of these systems. Subsequently, focusing on the traditional sliding mode controller, optimizations are implemented to refine the sliding mode convergence dynamics and the switching function, leading to the development of an optimal sliding mode controller model. Ultimately, simulation tests confirm that this optimized sliding mode speed controller achieves seamless transition without overshoot, swift response times, and robust disturbance rejection capabilities. Its performance in terms of responsiveness and anti-interference surpasses both the PI controller and the conventional sliding mode speed controller.
FIR noise reduction using GWO and Fast Kurtogram for extracting fault characteristic frequencies in rolling bearings
Authors: Jiang Shan , Li Minhui 
Published: December 2024

Abstract
Fast Kurtogram (FK) is a widely recognized method for detecting characteristic fault frequency bands. Nevertheless, its sensitivity to noise often causes diagnostic errors. This research seeks to enhance FK’s identification performance by implementing an adaptive FIR filter that mitigates noise. To validate this approach, single-point fault signals were obtained from the outer race, inner race, and rolling elements of bearings operating at four distinct motor speeds. These raw signals were then subjected to statistical analysis after normalization. To design the adaptive FIR filter, the study employs an enhanced Grey Wolf algorithm along with the Parks-McClellan algorithm to determine the optimal filter order and impulse response coefficients. Subsequently, band-pass filtering is applied to the fault characteristic frequency bands identified through FK. The fault characteristic frequencies are then extracted using envelope spectrum analysis. The bandwidth and fault characteristics derived from the processed signals are compared against those obtained from the unfiltered original signals. The findings indicate that optimal normalization preprocessing is crucial before filter design. The determined optimal order and impulse response coefficients enable the adaptive design of FIR filters. As a result, the FIR-filtered signal exhibits significantly fewer noise-induced anomalous peaks, thereby improving the signal-to-noise ratio and enhancing FK’s robustness against noise interference. Implementing an adaptive FIR filter for noise reduction significantly aids in more precise analysis and diagnosis of bearing conditions. Looking ahead, this study proposes integrating machine learning algorithms to further enhance the accuracy in identifying characteristic frequency bands associated with single-point faults in rolling elements.
Design and simulation analysis of a two-dimensional extended array structure
Authors: Lv Shibin , Tian Ye , Wang Liukai , Li Long 
Published: December 2024

Abstract
A compact and two-dimensional expandable extended array structure was designed to meet the electrical and structural compatibility requirements of a certain type of equipment. The transition from the distance between the RF component side RF channels A × B (mm) to the distance between the antenna array units a × b (mm) was achieved. The structural mechanical performance simulation was conducted. It was found that the deformation in the connector insertion direction was significant, which affected the reliability of the RF connection. Based on the simulation results, the original structural scheme was optimized and further improved to enhance the assembly, maintenance, and interchangeability of the extended array. The maximum structural deformation in the insertion direction of the RF connector was 0.19mm, which was reduced by 0.2mm compared to the previous optimized scheme with a structural deformation of 0.39mm. The large deformation area was significantly reduced. The stiffness of the structure was significantly improved, meeting the reliability requirements of multi-channel module RF blind insertion.
Empirical relationship with experimental model test results on change of blade number of Kaplan turbine on flow and efficiency characteristics
Authors: Mangla Mukesh 
Published: December 2024

Abstract
Axial flow Kaplan turbines with moveable guide vanes and rotating runner blades presents a complex flow. Turbine performance is dependent on loss and flow characteristics of different components. The runner is the heart of turbine and its design being the most dominant effect on performance of turbine characteristics in the turbine space. Blade design is combination of profile and solidity, the solidity was changed by changing number of blades and its effect on characteristics was investigated by model testing. In this paper an empirical relationship has been derived based on actual model test as per IEC 60193:2019 of all three types of Kaplan model with vertical runner, Tubular model with horizontal runner, and Bulb turbine model with horizontal runner. The relationship was investigated by changing the runner blade numbers 3, 4 or 5 on flow & efficiency characteristics. The experimental results analysis depicted a relationship in all three types of models having different blade profiles. Relationship among unit parameters like specific speed (nQE) Discharge factor (QED) and Speed factor (nED) were derived by regression analysis of test data.
Influence of cavitation simulation on Pelton turbine bucket performance
Authors: Liu Z , Liang Q , Xiao Y , Liu J , Qin C , Zhou Y , Li H , Du Q 
Published: December 2024

Abstract
Cavitation is one of the crucial problems faced by Pelton turbines operating under high water heads. To evaluate the influence of cavitation on the predicted Pelton turbine bucket performance, the conventional water-gas two-phase flow simulation and the water-vapor-gas two-phase three component flow simulation were carried out at the design operating point of a six-nozzle model Pelton turbine. The results showed that the inclusion of cavitation model might induce obvious influence on the bucket front surface torque curve after the peak, which was originated from the cavitation simulated at bucket back surface during the cut-in process of the next bucket, deteriorating the jet flow pattern with secondary flow enhanced. The inflow of deformed jet piece onto the bucket front surface finally affected the hydraulic performance of the bucket, accounting for the runner hydraulic loss of about 0.5% after the inclusion of cavitation model. This study provided the idea that for the types of buckets vulnerable with cavitation, cavitation phenomenon should be included in the simulation, so as to obtain the performance predicted closer to reality.
Experimental investigation of a FSFC variable speed pump-turbine prototype - Part1: penstock fatigue reduction and fast active power regulation
Authors: Nicolet C , Alligné S , Dreyer M. , Schmid J , Biner D , Münch-Alligné C , Lugon J , Hugo N 
Published: December 2024

Abstract
The Z’Mutt pumping station is located in Canton Valais-Wallis, in Switzerland and is part of the Grande Dixence hydroelectric scheme. The unit 5 of this station has recently been upgraded with a 5 MW variable speed reversible Francis pump-turbine equipped with Full Size Frequency Converter, FSFC, allowing the unit speed to be adjusted from −100% to +100%. This paper presents the methodology based on 1D numerical simulations including CFD/FEM runner damage hill chart to optimize the turbine start-up sequence to minimize both runner and penstock fatigue by taking advantage of the FSFC variable speed technology. FSFC allows for precise start-up trajectories in the n11-Q11 frame, to avoid runner high damage operating points, while reducing penstock pressure variations as compared to a classical fixed speed technology. This methodology resulted in the definition of 6 different FSFC start-up sequences, as well as the classical fixed speed start-up, which have been successfully implemented and tested on site. Site tests of fast transition from turbine to pump and vice versa are also showcased. Finally, fast active power regulation tests performed in pump mode are presented to show the ability of FSFC variable speed technology to provide ancillary grid service in pump mode.
Increasing grid flexibility – Implementation and testing of improved start and mode change procedures in a PSPP with double-fed induction machines and reversible pump-turbines
Authors: Weiser T , Fehringer F , Jung A R 
Published: December 2024

Abstract
Besides being a carbon-free and highly efficient energy storage technology, pumped-storage power plants (PSPP) offer operational flexibility which in turn eases the integration of volatile energy sources such as wind and solar energy into the electric grid. The flexibility to bring the power unit quickly to generation mode and thus to inject active power to the transmission grid involves various process transitions. In specific, this paper describes the implementation and respective site tests of the following mode changes: a) from standstill to generation mode by simultaneously accelerating the power unit to synchronization speed with the turbine and the voltage source inverter of a double-fed induction machine and b) from pump mode to generation mode. This work was part of the activities of the EU-funded H2020 project XFLEX HYDRO. The demonstration plant is the Frades 2 PSPP in Portugal, which is equipped with two reversible Francis-type pump turbines, each coupled to a 420 MVA double-fed induction machine. Based on recorded process values and additional measurements such as a turbine runner strain gauge measurement and shaft torque measurement, a detailed comparison of the different mode changes in terms of mechanical stress and vibrational behaviour was conducted. To a large extend, the obtained results and the applied methodology are valid as well for reversible pump-turbine sets with synchronous generators and start-up inverter technology. The outlook comprises a discussion about further improvements for the transition from pump mode to generation mode specifically for double-fed induction machines.
Numerical prediction of the fluid damping of a standing disc with a variable axial distance from a rigid wall
Authors: Khalfaoui K , Moraga G , Bareis J , Zorn M , Presas A , Riedelbauch S 
Published: December 2024

Abstract
Near-resonant flow-induced vibrations are a significant cause of fatigue damage in hydraulic impellers. The amplitude of these vibrations is limited mainly by the fluid damping, making its quantification paramount for the safety of hydraulic turbines. To study the fluid damping for low-specific-speed radial impellers, a submerged disc in still water with a variable vertical distance from a rigid wall is investigated. This setup serves as an abstraction of the axial gap between impeller hub and head cover, and of the modal behavior of impellers for the case of diametrical nodal lines. The fluid damping is computed numerically for the 3-nodal-diameters mode using the imposed modal motion approach for various axial gap sizes and vibration amplitudes. The results are contrasted with the experimental damping measured with the same setup. First, a simulation configuration that accurately replicates the experimentally measured damping in value and tendency is presented. The factors that would normally impede a valid numerical prediction are exposed and solutions are suggested. Second, the valid simulation results are thoroughly studied, and the flow field is visualized to gain insight into the physical mechanisms that cause the fluid mass and damping. As a result, the interaction between fluid and structure in this system is understood.
Advancing the Reliability of Residual Life Assessment for Turbines through Strain Gauge Measurements: Key Aspects and Latest Developments
Authors: von Locquenghien F , Fehringer F , Eissner M 
Published: December 2024

Abstract
With the need for flexible operation and an aging hydropower fleet, the importance of residual life assessment for turbines has been on the rise. While prediction methods are continuously improving, the most reliable data about the health status of a machine is obtained through measurement campaigns. Unlike fatigue evaluations during the design stage that include safety factors, residual life assessments require higher precision to enable owners to evaluate their assets and investments. The increased precision of a measurement campaign justifies the additional costs incurred.
This article emphasizes the significance of a careful review of all aspects, including load history, measurement data, transposition method, and material data. It also presents the latest developments in accordance with IEC 63230 and provides an example prototype measurement to underscore the importance of each aspect. Special attention is given to the transposition of strain data from the measurement location to the hot spot position and its impact on load sequences and stochastic loads. Through a sensitivity study, the article aims to provide a better understanding of the importance of each aspect in the residual life evaluation process.
Flow analysis and optimization study of main components of flow-type small hydro turbine system
Authors: Bae Seong-Han , Kim Subin , Kang Hyunsu , Kim Youn-Jea 
Published: December 2024

Abstract
Small hydro power generation refers to the production of electricity by harnessing the kinetic energy of water in small rivers or streams, typically generating up to 10 MW of power. The optimal shape combination of the watercone and turbine, according to the water flow rate, is crucial for maximizing the power generated. In this study, flow analysis using computational fluid dynamics was performed on Kaplan turbines to examine the effects of blade angle, volume flow rate and rotational speed on power generation. To ascertain the impact of variables on power generation, the internal flow field was examined. The findings demonstrated that an increased blade angle perpendicular to the flow direction resulted in a reduced incidence of vortices and cavitation formations within the turbine wake. A predictive model was generated using a design of experiment and response surface methodology to generate a predictive model to find the power generation for flow rates, blade angles and rotational speed within the experimental range.
Analysis of manganese (Mn) and copper (Cu) content in leachate water of Putri Cempo landfill, Surakarta
Authors: Matin H H A , Rachmawati S , Amira Z P , Purnamasari F , Ayuningtyas H R , Akromi M A I , Ainindyai D G 
Published: December 2024

Abstract
Leachate can contain hazardous components that can pollute the environment and health if not managed. This study aims to determine the content of heavy metals Mn and Cu in leachate from Putri Cempo Solo TPA and provide recommendations if the Mn and Cu values exceed the threshold. The method used is laboratory analysis. Analysis of Mn and Cu content was carried out using Atomic Absorption Spectroscopy by comparing the results of Mn and Cu content with quality standards according to PP 82/2001 Class IV concerning Water Quality Management and Water Pollution Control and PerMenKes 492/2010 concerning Mn content and PP 82/2001 Class IV concerning Water Quality Management and Water Pollution Control against Cu content. Laboratory test results showed that the Mn content was 33.7060 mg/l and Cu was 0.9294 mg/l. It is known that the maximum limit of heavy metal contamination Mn ranges from 0.1-0.4 mg/l and Cu is 0.2 mg/l. It was concluded that the heavy metal content of Putri Cempo landfill leachate has exceeded the quality standard. In order not to exceed the quality standard, it is recommended to treat leachate with coagulation-flocculation, adsorbent, and bioremediation processes.
Optimization of biogas production based on cow manure, tempeh waste and water hyacinth plants using the anaerobic digestion method
Authors: Arifan F , Broto R T D W , Saputri A B , Auliah M D , Fauzi M N , Sapatra E F , Praseto A N 
Published: December 2024

Abstract
The objective of this study is to produce biogas from livestock manure, water hyacinth and tempeh liquid waste which is actually dangerous for the surrounding environment. Water hyacinth has a high hemicellulose content, while animal waste and tempeh liquid waste can produces CH4 gas even the BOD and COD values are quite high. By using anaerobic digestion method, we will convert the material into methane gas. This research took a total of 28 days with by using other materials also such as NaOH, H2SO4, stater, aquadest. After conducting research, the most optimal results for the total biogas volume were obtained by variable A5 (86.63% cow dung: 4.70% water hyacinth: 8.66% tempeh liquid waste) with total volume of 2360 ml and the highest amount of methane/CH4 gas is obtained by A6 (86.63% cow dung: 4.70% water hyacinth: 8.66% tempeh liquid waste) with a value of 830581.83 ppm. While the lowest CH4 shows by variable A1 with total amount of 209601.39 ppm. This shows that water hyacinth is not sufficient to increase the potential amount of biogas produced.
The effect of additive compounds on the fresh properties of fly ash-based geopolymer binder
Authors: Indriyantho B R , Hidayat B A , Han A L , Prasetya B H , Priastiwi Y A , Sasmita D A , Januar H I 
Published: December 2024

Abstract
The utilization of fly ash-based geopolymer serves as a practical alternative to reduce the dependence on cement as a binding element, particularly in concrete construction. The increased viscosity of the geopolymer mixture requires careful evaluation of its effects on the fresh geopolymer’s physical properties, specifically its workability and setting time. This study investigates the impact of additive compounds, including superplasticizer, additional water, and extra cement, alone or in combination, on the initial properties of geopolymer mixtures, specifically geopolymer binders. The findings of workability testing conducted using the mini-slump test, and setting time analysis, performed using the Vicat apparatus, demonstrate that the inclusion of superplasticizer, additional water, and extra cement can either enhance or diminish the physical characteristics of the geopolymer combination. Hence, it is essential to evaluate the utilisation of the geopolymer combination to achieve the most optimal physical characteristics, while also taking into account its potential for on-site application.