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SSRN 2023年

作者： Ha, Hojin Ham, Sangwoo Ehsan, Adeeb Lee, Jeong Wan Interdisciplinary Program in Biohealth-Machinery Convergence Engineering Kangwon National University 1 Kangwondaehak-gil Gangwon-do Chuncheon-si24341 Korea Republic of Division of Mechanical & Biomedical Mechatronics and Materials Science and Engineering Kangwon National University 1 Kangwondaehak-gil Gangwon-do Chuncheon-si24341 Korea Republic of Kangwon Institute of Inclusive Technology Kangwon National University 1 Kangwondaehak-gil Gangwon-do Chuncheon-si24341 Korea Republic of

In this study, we aim to address the challenges of micro-hydropower generation in low-head environments. The authors reviewed and assessed various factors affecting the feasibility of micro-hydro systems, such as geographical constraints, construction costs, and grid connectivity. To overcome the limitations of conventional hydro turbines in such conditions, the authors proposed a novel cross-flow turbine. Initially, they designed and analyzed an inverted cross-flow turbine based on design rules established by previous researchers and performed numerical analyses. Four steps parametric studies were conducted to achieved optimum turbine values, such as runner diameter ratio and the number of blades, considering the maximum efficiency point from the previous step. The best efficiency point of the optimized design turbine was 72.92 % at a runner rotational speed of 170 RPM with a 0.75 runner diameter ratio and 35 blades. To validate the optimized design, the authors compared it with the initial design using hill charts and numerical values obtained from parametric studies. Overall, this research demonstrates the usefulness of computational fluid dynamics simulations and parametric studies in optimizing the design of an inverted cross-flow turbine under low head conditions. © 2023, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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Influence of Phase Transformation Coefficient on Thermomechanical Modeling of Laser Powder Bed Fusion for Maraging 300 Steel

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SSRN 2024年

作者： dos Santos Silva, Bruno Caetano de Figueiredo Soares, Lucas Coelho, Rodrigo Santiago Sitek, Wojciech Król, Mariusz Batalha, Gilmar Ferreira University Center SENAI CIMATEC SENAI Innovation Institute for Forming and Joining of Materials Av. Orlando Gomes 1845 Piata BA Salvador41650-010 Brazil Department of Mechatronics and Mechanical Systems Engineering Polytechnic School of Engineering University of Sao Paulo Av. Prof. Mello Moraes 2231 Butantã SP Sao Paulo05508-030 Brazil University Center SENAI CIMATEC Post-Graduation Program MPDS/GETEC/MCTI Av. Orlando Gomes 1845 Piata Salvador-BA41650-010 Brazil Department of Engineering Materials and Biomaterials Faculty of Mechanical Engineering Silesian University of Technology 18A Konarskiego St. Gliwice44-100 Poland

Manufacturing maraging steel components using laser-based powder bed fusion (LPBF) presents an attractive proposition for industries due to the material's combination of mechanical properties such as hardness, wear resistance, and toughness, and the capability to produce parts with complex geometries and high precision. Despite these advantages, the LPBF process induces defects such as distortion and residual stress associated with the complex thermal cycles, compromising final part quality. Numerical simulations have been developed to predict these defects. However, LPBF simulations remain challenging due to the complexity of the process and the substantial computational resources required. For maraging steel, for example, the occurrence of phase transformation promotes compressive stress that interferes in results and makes simulations inaccurate. This research aims to simulate a geometry with a circular inner channel and investigate distortion, volume fraction of martensite and equivalent stress results. Modeling was performed by varying phase transformation rate parameters to assess the impact of transformations on simulation outcomes. Results showed minimal impact of these parameters on distortions and equivalent stress. Equivalent stress results were compared with literature findings, while distortion results were validated against experimental data to validate the accuracy of the model. © 2024, The Authors. All rights reserved.

关键词： Phase transitions

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Analysis of ejecta ignition and velocity from 18650 Li-ion battery cells during thermal runaway

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Journal of Power Sources 2025年 653卷

作者： Vinny Gupta Matthew J. Dunn Andrew R.W. Macfarlane Tony Xiao Aamir Farooq Assaad R. Masri Department of Mechanical and Mechatronics Engineering University of Waterloo Waterloo N2L 3G1 Canada School of Aerospace Mechanical and Mechatronics Engineering The University of Sydney Sydney 2006 Australia CCRC King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia Mechanical Engineering Program PSE. King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia

Lithium-ion batteries are increasingly deployed across a range of energy storage applications, heightening the need to understand failure mechanisms such as thermal runaway. This study presents a new experimental platform focusing on optical accessibility to quantify the transient ejection and ignition dynamics from a single 18650-format cell with an NMC-811 cathode. High-speed optical diagnostics, including luminosity imaging, spectral emission, photodetection, and sound measurements, were employed to characterise the spatiotemporal evolution of ejected fragments and flaming ignition. Light and sound data are temporally correlated, demonstrating that ignition is followed by flame propagation that occurs rapidly and intermittently, with significant temporal variability despite consistent thermal runaway initiation temperatures. A gaseous ignition mode is identified where solid fragments ejected from the battery coated with metallic lithium ignite pyrophorically, acting as an ignition kernel for the flammable gaseous effluent. Atomic emission of neutral lithium (Li I) at 611 nm and 671 nm is detected during ignition and flaming ignition and is hypothesised to form via lithium plating or thermal decomposition of LiC 6 during thermal runaway. Atomic emission of sodium and potassium is also found, all of which is superimposed on the grey body distribution from luminous ejecta. In addition, the high-speed images are cross-correlated to provide time-resolved velocity fields and their statistical distributions of ejected particles during the entire thermal runaway event. Axial velocities possess a log-normal distribution, with peak velocities as large as 35 m s −1 . This work sets the platform for subsequent studies employing high-speed optical diagnostics to deliver a quantitative database to enable modelling of Li-ion battery thermal runaway and to understand flame-induced heating of adjacent cells in a battery module.

关键词： Lithium-ion battery Thermal runaway Ignition Venting Battery safety

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Near-Infrared I/II Nanophosphors with Cr3+/Ni2+ Energy Transfer for Bioimaging

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Advanced Optical Materials 2023年第15期11卷

作者： Satpathy, Aishwarya Huang, Wen-Tse Chan, Ming-Hsien Su, Ting-Yi Kamiński, Mikolaj Majewska, Natalia Mahlik, Sebastian Leniec, Grzegorz Kaczmarek, Slawomir M. Hsiao, Michael Liu, Ru-Shi Department of Chemistry National Taiwan University Taipei106 Taiwan Nanoscience and Technology Program Taiwan International Graduate Program Academia Sinica and National Taiwan University Academia Road 128 Nankang Taipei115 Taiwan Genomics Research Center Academia Sinica Academia Road Section 2 Nankang Taipei115 Taiwan Institute of Experimental Physics Faculty of Mathematics Physics and Informatics University of Gdansk Wita Stwosza 57 Gdansk80–308 Poland Department of Technical Physics Faculty of Mechanical Engineering and Mechatronics West Pomeranian University of Technology in Szczecin al. Piastow 19 Szczecin70–310 Poland

In the biomedical field, the use of fluorescence imaging in the second near-infrared (NIR-II) region is growing rapidly because it imparts the advantages of reduced autofluorescence and low photon scattering. The advantage of reduced scattering is that it increases penetration depth in vivo and improves imaging clarity. Herein, this work uses mesoporous silica, a biocompatible template that can be easily modified, functionalized, and loaded with drugs for use in several bioapplications. The ZnGa2O4 spinel oxide system is integrated into mesoporous silica and different concentrations of Cr3+ and Ni2+ are loaded in octahedral sites to obtain the highest emission intensity in the NIR-II region at 1285 nm via energy transfer from Cr3+ to Ni2+. Given that only a few nanophosphor systems with emission in the NIR-II region are available, this work attempts to establish emission in the NIR-II and NIR-I regions to obtain images in vivo with an increased penetration depth to 5 mm and improved clarity for bioimaging purposes. This system will open the door for biomedical research on other NIR-II nanophosphors. © 2023 Wiley-VCH GmbH.

关键词： Bioimaging

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Enhancement of Self-Trapped Exciton and Near-Infrared Emission in Bi3+/Er3+ Co-Doped Cs2Ag0.4Na0.6InCl6 Double Perovskite for Optical Telecommunications

SSRN

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SSRN 2022年

作者： Dave, Kashyap Huang, Wen-Tse Leśniewski, Tadeusz Lazarowska, Agata Grzegorczyk, Maciej Mahlik, Sebastian Leniec, Grzegorz Kaczmarek, Slawomir M. Liu, Ru-Shi Department of Chemistry National Taiwan University Taipei106 Taiwan Nanoscience and Technology Program Taiwan International Graduate Program Academia Sinica National Taiwan University Taipei115 Taiwan Institute of Experimental Physics Faculty of Mathematics Physics and Informatics University of Gdańsk Gdańsk80-308 Poland Department of Technical Physics Faculty of Mechanical Engineering and Mechatronics West Pomeranian University of Technology in Szczecin Piastow 48 Szczecin70-311 Poland Advanced Research Center of Green Materials Science and Technology National Taiwan University Taipei106 Taiwan

Erbium (Er) complexes are used as optical gain material for signal generation in the telecom C-band at 1540 nm, but they need a sensitizer to enhance absorption. Na+ substitution at Ag+ and Bi3+ doping at the In3+ site are possible strategies to enhance broadband emission in Cs2AgInCl6, which could be used as sensitizers to energy transfer into rare-earth elements. Herein, self-trapped exciton (STE) energy transfer to Er3+ at 1540 nm for low loss optical telecommunication applications is reported. An acid precipitation method is used to synthesize Cs2AgInCl6 and its derivative with Er3+, Bi3+, and Na+. Bare Cs2AgInCl6:Er emission signals are found to be weak at 1540 nm, but Bi3+ doping increased by 12 times, and Bi3+ and Na+ doping increased by up to 25 times signal intensity. Electron paramagnetic resonance spectroscopy characterized a decrease in axial symmetry over the Er3+ ion after substitutions of Na+ and Bi3+ in Cs2AgInCl6 at low temperature ( © 2022, The Authors. All rights reserved.

关键词： Bismuth compounds

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Self-supervised approach for facial movement based optical flow

arXiv

引用

arXiv 2021年

作者： Alkaddour, Muhannad Tariq, Usman Dhall, Abhinav Graduate Program in Mechatronics Engineering American University of Sharjah Sharjah United Arab Emirates Department of Electrical Engineering American University of Sharjah Sharjah United Arab Emirates Department of Human Centred Computing Monash University Melbourne Australia Department of Computer Science and Engineering Indian Institute of Technology Ropar Rupnagar India

Computing optical flow is a fundamental problem in computer vision. However, deep learning-based optical flow techniques do not perform well for non-rigid movements such as those found in faces, primarily due to lack of the training data representing the fine facial motion. We hypothesize that learning optical flow on face motion data will improve the quality of predicted flow on faces. The aim of this work is threefold: (1) exploring self-supervised techniques to generate optical flow ground truth for face images;(2) computing baseline results on the effects of using face data to train Convolutional Neural Networks (CNN) for predicting optical flow;and (3) using the learned optical flow in micro-expression recognition to demonstrate its effectiveness. We generate optical flow ground truth using facial key-points in the BP4D-Spontaneous dataset. The generated optical flow is used to train the FlowNetS architecture to test its performance on the generated dataset. The performance of FlowNetS trained on face images surpassed that of other optical flow CNN architectures, demonstrating its usefulness. Our optical flow features are further compared with other methods using the STSTNet micro-expression classifier, and the results indicate that the optical flow obtained using this work has promising applications in facial expression analysis. © 2021, CC BY.

关键词： Optical flows

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Influences of key factors on river water quality in urban and rural areas: A review

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Case Studies in Chemical and Environmental engineering 2023年 8卷

作者： Anh, Nguyen Tuan Can, Le Duy Nhan, Nguyen Thi Schmalz, Britta Luu, Tran Le Doctoral Training Program in Sustainable Urban Development Vietnamese German University Viet Nam Nong Lam University of Ho Chi Minh City Gia Lai Campus Viet Nam Department of Mechatronics and Sensor Systems Technology Vietnamese German University Vanh Dai 4 Quarter 4 Thoi Hoa Ward Ben Cat Binh Duong Province Viet Nam Master Program in Water Technology Reuse and Management Vietnamese German University Vanh Dai 4 Quarter 4 Thoi Hoa Ward Ben Cat Binh Duong Province Viet Nam Chair of Engineering Hydrology and Water Management Technical University of Darmstadt Germany

Water quality in rivers is deteriorating in urban and rural areas due to natural and anthropogenic factors. Understanding how changes and factors affect river water quality is crucial for managing water quality in river basins. This review focuses on analyzing key factors affecting water quality, and the temporal and spatial variations of water quality in rivers flowing in rural and urban areas. Natural processes such as weathering of rocks, evapotranspiration, atmospheric deposition, climate change, and natural disasters cause changes in the quality of river water. Anthropogenic factors could stem from industrial effluents, domestic activities, and agricultural activities such as the application of fertilizers, manures, pesticides, animal husbandry activities, irrigation practices, deforestation, and aquaculture. The seasonal variations in river water quality are discussed, and land use or cover could affect water quality parameters in a negative or positive way. In addition to traditional contaminants such as biodegradable organic matter, heavy metals, and pathogens, emerging and persistent pollutants such as organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), perfluoroalkyl and polyfluoroalkyl substances (PFASs), and phamaceutic active compounds (PhACs) has been found in many rivers, which could pose a threat to human and animal health. The comparison of key factors and parameters in urban and rural areas is also clarified, which provides authorities and policymakers with a deep understanding and supports decision-making in sustainable water management. © 2023 The Authors

关键词： River basin River water quality Rural areas Urban areas Water pollution

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Numerical study of cavitating flow in orifices and its effect on spray characteristics

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Journal of Hydrodynamics 2018年第5期30卷 908-919页

作者： Morteza Ghorbani Mechatronics Engineering Program Faculty of Engineering and Natural Science Sabanci University Department of Biomedical Engineering and Health Systems KTH Royal Institute of Technology

The bubbly flow regime inside orifices has significant effects on several applications, and studying its trend along an orifice could be helpful in identifying the flow mechanism in various situations. The flow regime inside an orifice depends on the situation which has been specified for the orifice. Orifice geometry has a considerable effect on bubbly flow in injectors. Meanwhile, spray characteristics are influenced by the fuel flow inside an orifice, which has strong effects on the mixture of fuel-air. In this study, spray characteristics are studied for different values of the orifice angle. The cavitation phenomenon which occurs inside an orifice varies in intensity and patterns at different angles of the orifice and consequently has diverse effects on spray characteristics. The governing equations are solved by the SIMPLE algorithm. The spray flow is modeled by the discrete droplet method（DDM）, the droplet breakup is modeled by the WAVE model, and the primary breakup is modeled by the DIESEL BREAK UP model. In order to generate cavitation phenomenon inside orifices and investigate its effect on spray characteristics, the angle of orifice with respect to the injector body is varied and the problem is studied for different angles of orifice.

关键词： Cavitation iinjector angle microchannel spray

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Rabi antenna using microstrip add-drop multiplexer for electron warp speed investigation

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Chinese Optics Letters 2022年第7期20卷 80-87页

作者： Somchat Sonasang Prakasit Prabpal Piya Sirikan Pratimakorn Hakaew Nhat Truong Pham Preecha Yupapin Kanad Ray Sarawoot Boonkirdram Department of Electronic Technology Faculty of Industrial TechnologyNakhon Phanom UniversityNakhon Phanom 48000Thailand Department of Electrical Technology School of Industrial TechnologySakonnakhon Technical CollegeInstitute of Vocational Education Northeastern Region 2Sakonnakhorn 47000Thailand Division of Computational Mechatronics Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 72915Vietnam Faculty of Electrical and Electronics Engineering Ton Duc Thang UniversityHo Chi Minh City 72915Vietnam Amity School of Applied Sciences Amity University RajasthanJaipurIndia Faubert Lab Universitéde MontréalH3T 1P1 MontréalCanada Facultad de CienciasFisico-Matematicas Benemérita Universidad Autónoma de PueblaAv.San Claudio y Av.18 surCol.San Manuel Ciudad UniversitariaPuebla Pue 72570Mexico Program of Electrical and Electronics Faculty of Industrial TechnologySakon Nakhon Rajabhat UniversitySakon Nakhon 47000Thailand

This work presents experimental results of Rabi antenna characteristics using the coupled line microstrip *** was constructed by a modified coupled line microstrip four-port network,which is known as an add-drop *** driven AC input enters the device via an input port using the suitable frequency and coupled line microstrip ring *** multilevel system is generated by a wave-particle aspect before the two-level system is *** the resonance,the transitions of the states induce the energy called whispering gallery mode(WGM)at the circuit center,which is the squeezed *** generated electron oscillation within the WGM envelope oscillated by the frequency is known as the Rabi *** the successive filtering with continuous AC input via the selected port,the electron cloud warp speed can be generated and achieved inside the two-level *** constructed microstrip ring radius is 25 mm,and the experimental results of the Rabi antenna characteristics are in good agreement with the simulation *** obtained resonant antenna oscillation frequency is 2.103 *** electron cloud warp speed of 1.100c and time dilation of 0.006μs are obtained.

关键词： integrated photonics waveguide microwave photonics Rabi antenna

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A Normal Distribution Transform-Based Radar Odometry Designed For Scanning and Automotive Radars

arXiv

引用

arXiv 2021年

作者： Kung, Pou-Chun Wang, Chieh-Chih Lin, Wen-Chieh Graduate Degree Program of Robotics National Chiao Tung University Hsinchu Taiwan Department of Electrical and Computer Engineering National Chiao Tung University The Mechanical and Mechatronics Systems Research Laboratories Industrial Technology Research Institute Hsinchu Taiwan Department of Computer Science National Chiao Tung University Hsinchu Taiwan

Existing radar sensors can be classified into automotive and scanning radars. While most radar odometry (RO) methods are only designed for a specific type of radar, our RO method adapts to both scanning and automotive radars. Our RO is simple yet effective, where the pipeline consists of thresholding, probabilistic submap building, and an NDT-based radar scan matching. The proposed RO has been tested on two public radar datasets: the Oxford Radar RobotCar dataset and the nuScenes dataset, which provide scanning and automotive radar data respectively. The results show that our approach surpasses state-of-the-art RO using either automotive or scanning radar by reducing translational error by 51% and 30%, respectively, and rotational error by 17% and 29%, respectively. Besides, we show that our RO achieves centimeter-level accuracy as lidar odometry, and automotive and scanning RO have similar accuracy. Copyright © 2021, The Authors. All rights reserved.

关键词： Optical radar

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