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Boost DC-DC converter with regenerative snubber

Energy Reports 2024年 12卷 798-819页

作者： Yau, Yeu-Torng Department of Ph.D. Program Prospective Technology of Electrical Engineering and Computer Science National Chin-Yi University of Technology Taichung Taiwan Department of Electrical Engineering National Chin-Yi University of Technology Taichung Taiwan

To accommodate the wide range of input voltages supplied by redundant batteries and ensure an adequate hold-up time for communication systems during utility power failures, power supplies used in 5 G base stations typically include a front-end boost converter as the first stage and a second-stage isolated converter. In this paper, a new topology for a regenerative snubber in boost converters is proposed. Compared to traditional active or passive snubber topologies, the proposed snubber offers the advantages of having fewer components and occupying less space. Moreover, it does not require additional active devices and can be driven by widely-used commercial PWM control integrated circuits, achieving a higher level of cost-effectiveness and offering increased industrial applications. The final prototype of a power supply for a networking switch hub (as used in 5 G base stations) is fabricated to demonstrate the feasibility of the proposed method. © 2024 The Authors

关键词： Topology

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Application of machine learning technique for predicting and evaluating chloride ingress in concrete

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Frontiers of Structural and Civil engineering 2022年第9期16卷 1153-1169页

作者： Van Quan TRAN Van Loi GIAP Dinh Phien VU Riya Catherine GEORGE Lanh Si HO Department of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam Civil and Environmental Engineering Program Graduate School of Advanced Science and EngineeringHiroshima UniversityHiroshima 739-8527Japan

The degradation of concrete structure in the marine environment is often related to chloride-induced corrosion of reinforcement ***,the chloride concentration in concrete is a vital parameter for estimating the corrosion level of reinforcement *** research aims at predicting the chloride content in concrete using three hybrid models of gradient boosting(GB),artificial neural network(ANN),and random forest(RF)in combination with particle swarm optimization(PSO).The input variables for modeling include exposure condition,water/binder ratio(W/B),cement content,silica fume,time exposure,and depth of *** results indicate that three models performed well with high accuracy of prediction(R2⩾0.90).Among three hybrid models,the model using GB_PSO achieved the highest prediction accuracy(R2=0.9551,RMSE=0.0327,and MAE=0.0181).Based on the results of sensitivity analysis using SHapley Additive exPlanation(SHAP)and partial dependence plots 1D(PDP-1D),it was found that the exposure condition and depth of measurement were the two most vital variables affecting the prediction of chloride *** the number of different exposure conditions is larger than two,the exposure significantly impacted the chloride content of concrete because the chloride ion ingress is affected by both chemical and physical *** study provides an insight into the evaluation and prediction of the chloride content of concrete in the marine environment.

关键词： gradient boosting random forest chloride content concrete sensitivity analysis

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A hybrid machine learning model to estimate self-compacting concrete compressive strength

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Frontiers of Structural and Civil engineering 2022年第8期16卷 990-1002页

作者： Hai-Bang LY Thuy-Anh NGUYEN Binh Thai PHAM May Huu NGUYEN Civil Engineering Department University of Transport TechnologyHanoi 100000Vietnam Civil and Environmental Engineering Program Graduate School of Advanced Science and EngineeringHiroshima UniversityHiroshima 739-8527Japan

This study examined the feasibility of using the grey wolf optimizer(GWO)and artificial neural network(ANN)to predict the compressive strength(CS)of self-compacting concrete(SCC).The ANN-GWO model was created using 115 samples from different sources,taking into account nine key SCC *** validation of the proposed model was evaluated via six indices,including correlation coefficient(R),mean squared error,mean absolute error(MAE),IA,Slope,and mean absolute percentage *** addition,the importance of the parameters affecting the CS of SCC was investigated utilizing partial dependence *** results proved that the proposed ANN-GWO algorithm is a reliable predictor for SCC’s *** that,an examination of the parameters impacting the CS of SCC was provided.

关键词： artificial neural network grey wolf optimize algorithm compressive strength self-compacting concrete

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Visualization of Methamphetamine-Contaminated Fingermarks on Glass Surfaces by Field Emission Scanning Electron Microscope for Forensic Investigation

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Journal of Forensic science and Medicine 2023年第1期9卷 6-11页

作者： Sarah Aliah Amir Sarifudin Kah Haw Chang Bee Ee Khoo Ahmad Fahmi Lim Abdullah Forensic Science Program School of Health SciencesHealth CampusUniversiti Sains MalaysiaKelantanMalaysia Mechatronic Engineering Program School of Electrical and Electronic EngineeringEngineering CampusUniversiti Sains MalaysiaPenangMalaysia

Background:Fingermark is an individual’s primary identification *** is helpful in determining individuals involved in illegal activities and is frequently encountered in clandestine *** forensic investigation,the critical question to be answered is whether a fingermark was left on a surface before or after the initiation of an unlawful *** and Objectives:This study aimed to investigate the visualization of methamphetamine-contaminated fingermarks on glass surfaces and estimate the immediacy of their *** and Methods:In this study,the prior-deposition contaminated fingermarks,i.e.,fingermarks deposited a surface priorly contaminated by methamphetamine,and the postdeposition contaminated fingermarks,i.e.,fingermarks deposited on a clean surface but subsequently contaminated with methamphetamine were visualized and compared using Field Emission Scanning Electron Microscope(FESEM).Results:Under FESEM,the latent fingermarks and the crystalline structure of methamphetamine were clearly *** postdeposition contaminated fingermarks appeared in smudge conditions in all the three replicate samples,where the ridge and nonridge areas could not be *** the contrary,the prior-deposition contaminated fingermark demonstrated distinct separations between ridges and ***,the application of fingerprint powders reduced the possibility to determine the immediacy of ***:To conclude,both prior-deposition contaminated fingermarks and postdeposition contaminated fingermarks can be discriminated,providing information on the instance when a fingermark was left on a surface.

关键词： Fingermark methamphetamine scanning electron microscope visualization powder

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Assessment of the wall effects on the cellular structure by combined planar laser-induced fluorescence and Rayleigh scattering

Assessment of the wall effects on the cellular structure by ...

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AIAA science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Alicherif, Mhedine Chavez, Samir B. Rojas Chatelain, Karl P. Guiberti, Thibault F. Lacoste, Deanna A. PO box 4700 Thuwal23955-6900 Saudi Arabia Mechanical Engineering Program Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

This study investigates the structure of the detonation front in a stoichiometric H2-air mixture (2H2-O2-3.76N2), seeded with 2000,ppm of NO, at 25,kPa and 293,K, for two channel positions: centered and near thewalls (side). Acombination of NO-PLIF and Rayleigh scattering techniques was used to characterize key features of the detonation front, such as unburned gas pockets, transverse waves, cellular irregularities, and triple point trajectories. The irregular features were categorized into four distinct "events", and their occurrence probabilities were determined for each configuration based on samples of over one hundred detonation cells. The centered configuration showed fewer irregularities with lower probabilities for all events, indicating a regular structure. In contrast, the side configuration showed higher probabilities for all events, indicating a more irregular structure closer to the walls. With the same techniques a correlation between the formation of unburned gas pockets and a local thickening of the front was investigated. While the processes seems to be interconnected in the center of the channel this correlation is lost closer to the walls. The results suggest a strong dependence between the occurrence detonation irregularities and their position relative to the walls. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Rayleigh scattering

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A Burst Mode and Variable Frequency Voltage Sharing Control Mechanism for an Adjustable High Voltage Pulsed Converter

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IEEE Journal of Emerging and Selected Topics in Power Electronics 2023年第2期11卷 1888-1900页

作者： Lin, Chang-Hua Ahmad, Javed Li, Ren-Hao Liu, Hwa-Dong National Taiwan University of Science and Technology Department of Electrical Engineering Taipei106 Taiwan National Taiwan Normal University Undergraduate Program of Vehicle and Energy Engineering Taipei106 Taiwan

This article presents a modular adjustable high-voltage pulse (MAHVP) generation system. The proposed MAHVP generation system uses a combination of full-bridge LLC resonant converters whose input terminals are connected in parallel and whose output terminals are in series to boost the output voltage;input parallel output series configuration efficiently increases the power holding capabilities of the overall system. The MAHVP generation system uses a novel burst mode and variable frequency voltage sharing (BMVFVS) control mechanism, the BMVFVS control mechanism senses the type of load if the MAHVP generation system needs to operate at a heavy load, it uses the variable frequency voltage sharing method to divide the power equally between the modules to enhance the overall performance. For light load conditions, the MAHVP generation system operates in burst mode, and the BMVFVS control mechanism combined with the frequency modulation technique is used to control the amplitude and pulsewidth of the output voltage smoothly and efficiently. A hardware prototype of 2.4 kW is developed, and experimental results are taken to verify the feasibility and validity of the proposed system, the maximum output voltage of the developed two-module prototype is tested up to 6 kV at the high efficiency of 97%. © 2013 IEEE.

关键词： Power converters

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Evaluating mechanism of banana pseudo-stem retting using seawater:A cost-effective surface pre-treatment approach

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Journal of Bioresources and Bioproducts 2024年第3期9卷 322-335页

作者： Prince Hotor Ahmed H.Hassanin Osbert Akatwijuka Mohamed A.H.Gepreel Mitsuo Yamamoto Yukie Saito Ahmed Abdel-Mawgood Egypt-Japan University of Science and Technology Biotechnology ProgramAlexandria GovernorateNew Borg Al Arab 21934Egypt Alexandria University Department of Textile EngineeringAlexandria GovernorateBab Sharqi 5424041Egypt Egypt-Japan University of Science and Technology Material Science and EngineeringAlexandria GovernorateNew Borg Al Arab 21934Egypt Graduate School of Agricultural and Life Sciences The University of TokyoBunkyo-KuTokyo 113-8657Japan

Retting has been employed to extract natural fibers from agricultural wastes as a biological and cost-effective approach for *** its global abundance,banana pseudo-stem is a promising agro-waste for lignocellulosic fiber *** this study,fibers were extracted from the pseudo-stems after being pre-treated under four conditions using seawater at room temperature for up to 35 d Bacterial isolation from the fresh seawater sample and screening for ligninolytic ability were *** load as well as laccase and manganese peroxidase enzyme activity profile assay during the retting duration were *** transform infrared(FT-IR)and X-day diffraction(XRD)analyses were also examined for both pre-treated and untreated extracted *** results shows that six out of the eight bacterial isolates had the ability to degrade *** treatments(Raw stem+Raw seawater)and(Autoclaved stem+Raw seawater)recorded the highest viable bacterial load of 9.24×102 and 4.46×102 CFU,respectively,on the 14th day of the retting ***,the highest laccase and manganese peroxidase enzymes activity was recorded for(Raw stem+Raw seawater)and(Autoclaved stem+Raw seawater)treatments in the second to the third *** FT-IR spectra of the pre-treated fibers revealed relative reductions in peaks attributed to polysaccharides and other amorphous substances for all retting *** XRD diffractogram revealed that the crystallinity index(CI)of pre-treated fibers increased in all seawater retting treatment ***,the CI for fibers pre-treated under enzymatic conditions were enhanced even after five *** analysis for selected bacterial isolates showed homology to sequences of Bacillus velezensis,Shewanella sp.L8–5,and Citrobacter amalonaticus and Bacillus subtilis j8 *** these findings,it was suggested that physical,biological,and chemical actions were collectively involved in the seawater retting process of banana ps

关键词： Seawater retting Banana pseudo-stem Natural fiber Enzyme activity Colony forming unit

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Biosurfactant-Enhanced Remediation of Oil-Contaminated Groundwater

Biosurfactant-Enhanced Remediation of Oil-Contaminated Groun...

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2024 SPE Europe Energy Conference and Exhibition, EURO 2024

作者： Sanchez-Huerta, C. Hong, P.-Y. Zhang, S. Alahmari, M.M. Humam, A.A. Environmental Science and Engineering Program Biological and Environmental Science and Engineering Division King Abdullah University of Science and Technology Thuwal Saudi Arabia Saudi Aramco’s EXPEC Advanced Research Center Dhahran Saudi Arabia

ISBN: (纸本)9781959025399

Groundwater contaminated with hydrocarbons poses a serious hazard to the environment. Current oil-contaminated groundwater remediation techniques include physical, chemical, and biological approaches. Chemical surfactants have the potential of high toxicity due to their low biodegradability. Biosurfactants have demonstrated similar performance to that of chemical surfactants, with the added value of low toxicity. The use of surfactants directly over the top layer of crude oil-contaminating groundwater, where environmental conditions are different from that in above ground surfaces, have yet not been explored in depth. Therefore, this study aims to investigate the potential of four different surfactants for their ability to be deployed in conditions mimicking underground aquifer so as to enhance remediation of oil-contaminated groundwater. Selected surfactants comprised two chemical surfactants, referred to as A and B, and two biosurfactants, referred to as BS and C. Surfactants were evaluated for their ability (i) to reduce the crude oil layer thickness through facilitating oil dispersion, and (ii) the extent of natural biodegradation it can achieve. Experiments were performed in glass flasks containing synthetic groundwater and crude oil supplemented with surfactant added at the three different surfactants: oil ratios (S:O) 1:5, 1:10 and 1:50. Reduction of crude oil layer thickness, water turbidity, and bacterial cell count were continuously monitored for 60 days to observe the temporal variation of biosurfactant activity towards crude oil. The performance of surfactants A, C and BS in reducing oil layer thickness was influenced by temperature and S:O ratios. Overall, increase in temperature increased the performance of these three surfactants. S:O ratio was optimal at 1:10 for surfactants A and BS, and at 1:5 for surfactant C. Surfactants A and C reduced the oil layer thickness mainly by means of dispersion and less by biodegradation. In contrast, surfactant BS ex

关键词： Surface active agents

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Contour Tracking Control for High-Order Fully Actuated Multi-Axis Motion Control Systems 26

Contour Tracking Control for High-Order Fully Actuated Multi...

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26th International Conference on Industrial Technology, ICIT 2025

作者： Wu, Qi Hua, Chengyuan Gu, Caoyuan Wang, Yao-Wei Zhang, Wen-An Takagi, Shigeyuki College of Information Engineering Zhejiang University of Technology Hangzhou China College of Information Science and Engineering Wuhan University of Science and Technology Wuhan China Enginnering Program Tokyo University of Technology Tokyo Japan

ISBN: (纸本)9798331521950

This paper investigates the contour tracking control problem for a class of multi-axis motion control systems (MAMSs) with parameter uncertainties and external disturbances. First, a high-order fully actuated (HOFA) tracking error model of the MAMSs is established, and a fully actuated controller is designed to transform it into a linear constant system model with arbitrarily configurable poles. Second, parameter uncertainties and external disturbances are regarded as lumped disturbances of the system according to the concept of equivalent input disturbance (EID), and a generalized extended state observer (GESO) is designed to estimate the lumped disturbance. Then, the tracking controller for the single-axis is designed via the model predictive control (MPC) method in order to compensate for the disturbance effect through a feed-forward control method. On this basis, a cross-coupled control (CCC) strategy is used to further compensate the contour tracking error of MAMSs. The effectiveness of the proposed method are verified through a simulation of a two-axis motion control system. © 2025 IEEE.

关键词： Predictive control systems

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Correlation of work function and stacking fault energy through Kelvin probe force microscopy and nanohardness in diluteα-magnesium

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Journal of Magnesium and Alloys 2024年第1期12卷 237-250页

作者： Yigit Türe Ali Arslan Kaya Hüseyin Aydin Jiang Peng Servet Turan Eskisehir Technical University Porsuk Vocational SchoolElectronics and Automation DepartmentProgram of MechatronicsEskisehirTurkey Mugla Sitki Kocman University Engineering FacultyMetallurgy and Materials Engineering DepartmentMuglaTurkey Hüseying Aydın TUBITAK MRCTurkey Jiang Peng Chongqing UniversityChina Eskisehir Technical University Engineering FacultyMaterials Science and Engineering DepartmentEskisehirTurkey

Electronic interactions of the Group 2A elements with magnesium have been studied through the dilute solid solutions in binary Mg-Ca,Mg-Sr and Mg-Ba *** investigation incorporated the difference in the‘Work Function'(ΔWF)measured via Kelvin Probe Force Microscopy(KPFM),as a property directly affected by interatomic bond types,*** electronic structure,nanoindentation measurements,and Stacking Fault Energy values reported in the *** was shown that the nano-hardness of the solid-solutionα-Mg phase changed in the order of Mg-Ca>Mg-Sr>***,it was shown,by also considering the nano-hardness levels,that SFE of a solid-solution is closely correlated with its‘Work Function'***-hardness measurements on the eutectics andΔWF difference between eutectic phases enabled an assessment of the relative bond strength and the pertinent electronic structures of the eutectics in the three *** withΔWF and at least qualitative verification of those computed SFE values with some experimental measurement techniques were considered important as those computational methods are based on zero Kelvin degree,relatively simple atomic models and a number of *** asserted by this investigation,if the results of measurement techniques can be qualitatively correlated with those of the computational methods,it can be possible to evaluate the electronic structures in alloys,starting from binary systems,going to ternary and then multi-elemental *** investigation has shown that such a qualitative correlation is *** all,the SFE values are not treated as absolute values but rather become essential in comparative investigations when assessing the influences of alloying elements at a fundamental level,that is,free electron density *** study indicated that the principles of‘electronic metallurgy'in developing multi-elemental alloy systems can be followed via practical experimental methods,i.e.ΔWF measurements using KPF

关键词： Mg alloys Dilute alloys Work function Stacking fault energy Kelvin probe force microscopy Short range order Miedema Nanoindentation Eutectics

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