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In-situ heat treatment via preheating and liquid cooling during high-speed coating of gears by directed energy deposition

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CIRP Journal of Manufacturing science and technology 2025年 61卷 114-127页

作者： Masaya Yokota Shiho Takemura Ryo Koike Teppei Maki Kazuhiro Takaki Takanori Mori Yoko Hirono Yasuhiro Kakinuma Department of System Design Engineering Faculty of Science & Technology Keio University 3–14-1 Hiyoshi Kohoku-ku Yokohama Kanagawa Japan Nissan Motor Co. Ltd Japan DMG MORI Co. Ltd Japan

Automobile electrification has increased demand for higher-performance gears in drivetrains with specialized functional requirements beyond what conventional carburizing heat treatment can deliver. While carburizing is effective for mass production, it faces inherent limitations in achieving advanced material properties needed for next-generation applications. Therefore, this study proposes a high-speed coating method on rotational gear surfaces using directed energy deposition (DED). The proposed method can form the coating layer continuously and efficiently on the complex-shaped teeth of the gear, compared to the common method that forms coating along a complicated path matching the part’s geometry. Furthermore, a localized heat treatment system integrating laser preheating and liquid cooling is introduced to precisely control material characteristics of the coating layer. Experimental results demonstrate that this combined heat treatment achieves a crack-free, hard coating layer on preformed gears. This method shows significant potential for producing customized, high-performance gears for specialized applications in next-generation vehicles while reducing process complexity.

关键词： Directed energy deposition High-speed coating Gear Liquid cooling

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Federated Cubic Regularized Newton Learning with Sparsification-amplified Differential Privacy

arXiv

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arXiv 2024年

作者： Huo, Wei Liu, Changxin Ding, Kemi Johansson, Karl Henrik Shi, Ling Department of Electronic and Computer Engineering Hong Kong University of Science and Technology Hong Kong Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Sweden Digital Futures StockholmSE-10044 Sweden School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen518055 China

This paper investigates the use of the cubic-regularized Newton method within a federated learning framework while addressing two major concerns that commonly arise in federated learning: privacy leakage and communication bottleneck. We introduce a federated learning algorithm called Differentially Private Federated Cubic Regularized Newton (DP-FCRN). By leveraging second-order techniques, our algorithm achieves lower iteration complexity compared to first-order methods. We also incorporate noise perturbation during local computations to ensure privacy. Furthermore, we employ sparsification in uplink transmission, which not only reduces the communication costs but also amplifies the privacy guarantee. Specifically, this approach reduces the necessary noise intensity without compromising privacy protection. We analyze the convergence properties of our algorithm and establish the privacy guarantee. Finally, we validate the effectiveness of the proposed algorithm through experiments on a benchmark dataset. © 2024, CC BY.

关键词： Federated learning

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Study on irradiation damage of rpv steels based on coupling cluster dynamics and crystal plasticity finite element method

Study on irradiation damage of rpv steels based on coupling ...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Wang, Xiaotong Luo, Ying Dong, Yuanyuan Yao, Weihua Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9780791883785

Irradiation hardening is one of the most important aging effects of reactor pressure vessel (RPV) steel in long-term service. A number of studies have indicated that irradiation hardening is mainly caused by irradiation induced defects, such as dislocation loops and precipitates. In this paper, we have simulated the irradiation damage of low-copper reactor pressure vessel (RPV) steel. The generation of Mn-Ni-Si precipitates is simulated by the cluster dynamics model based on rate theory. On this basis, the crystal plasticity finite element method based on modified crystal plasticity model is used to simulate the effect of Mn-Ni-Si precipitates on the mechanical properties of RPV steels. The simulated results has been compared with the experimental results from the literature. By coupling the cluster dynamics and the crystal plastic finite element method, we suggest a multi-scale simulation method to simulate and predict irradiation damage of RPV steel. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Finite element method

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Effect of Particle Size Distribution on the Transmission Efficiency of Atomized Water to the Tracheal Tube

SSRN

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SSRN 2023年

作者： Asakura, Takumi Yoshioka, Keisuke Ogawa, Ami Kurashina, Yuta School of Mechanical Engineering Graduate School of Science and Technology Tokyo University of Science Japan Department of System Design Engineering Faculty of Science and Technology Keio University Yokohama Japan Division of Advanced Mechanical Systems Engineering Institute of Engineering Tokyo University of Agriculture and Technology Japan

Ultrasonic atomization is a widely used technology. As the atomization device, lead zirconate titanate (PZT) and lithium niobate (LN) are comparatively investigated through experimental and numerical schemes. However, knowledge on a profitable scheme by which to efficiently deliver the atomized particles into the tracheal tube remains unclear. In this study, the physical difference of the transmission efficiency of water particles atomized by PZT and LN devices was measured. The water particles atomized by PZT and LN were injected into a human airway model including a nasal cavity and bronchial tube. The distribution of the amount of transmitted particles deposited at each of the monitoring positions was then estimated using the results of image analysis of color intensity. As a result, the atomized particles of the PZT device, which produced larger particles than the LN device, were more strongly affected by inertia and tended to be deposited at the area closer to the entrance of the nasal cavity. In contrast, the particles produced by the LN device tended to be transmitted deeper into the trachea. The experimental results indicated that the particle size distribution of PZT and LN, which have quite different maximum sizes of particles, largely influences the spatial distribution characteristics of particle deposition along the airway from the nasal cavity to the trachea. © 2023, The Authors. All rights reserved.

关键词： Particle size analysis

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Burnup performance analysis for candidate materials of the LWR accident tolerant control rod 14

Burnup performance analysis for candidate materials of the L...

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14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water reactor Fuel Performance Conference, TOP FUEL 2019

作者： Liu, Yong Li, Mancang Yu, Yingrui Xiao, Peng Wang, Xingbo Zhang, Bin Wang, Dongyong Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China 328# Section 1 Changshun Avenue Chengdu China

The accident tolerant fuel (ATF) is considered to be one of the most advanced concepts to improve the safety of light water reactors (LWRs). The accident tolerant control rod (ATCR) is a significant aspect in the ATF concept. The melting temperature of traditional LWR control rod (CR) materials, such as silver-indium-cadmium (AIC) alloy, is too low to endure the high temperature under several accident conditions. Consequently, varieties of candidate materials for control rod have been proposed in the previous researches because of the outstanding characters of high-temperature behavior, as well as reactivity worth, stability in coolant water and so on. In this paper, the burnup performance of the sesquioxides of the rare-earth elements (RE2O3) and the hafnia (Hf) are analyzed and compared to the traditional AIC control rod. Two parameters are chosen to reveal the burnup performance of the candidate control rod materials, the initial control rod reactivity worth and the stability of the control rod reactivity worth along with the assembly burnup. The candidate-material control rods and the AIC control rod are placed in the ATF assembly with the same conditions, and the assembly is depleted to sufficient burnup. Numerical results indicate that Eu2O3, Dy2O3, Sm2O3 and Hf are excellent ATCR materials compared to AIC. The initial control rod reactivity worth of these materials is not less than that of AIC, and the burnup stability is outstanding, especially Eu2O3 and Dy2O3 Copyright © GLOBAL 2019 - International Nuclear Fuel Cycle Conference and TOP FUEL 2019 - Light Water reactor Fuel Performance *** rights reserved.

关键词： Hafnium oxides

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DPN: Decoupling Partition and Navigation for Neural Solvers of Min-max Vehicle Routing Problems

arXiv

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arXiv 2024年

作者： Zheng, Zhi Yao, Shunyu Wang, Zhenkun Tong, Xialiang Yuan, Mingxuan Tang, Ke Department of Computer Science and Engineering Southern University of Science and Technology Shenzhen China Department of Computer Science City University of Hong Kong Hong Kong School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China China Huawei Noah’s Ark Lab Shenzhen China

The min-max vehicle routing problem (min-max VRP) traverses all given customers by assigning several routes and aims to minimize the length of the longest route. Recently, reinforcement learning (RL)-based sequential planning methods have exhibited advantages in solving efficiency and optimality. However, these methods fail to exploit the problem-specific properties in learning representations, resulting in less effective features for decoding optimal routes. This paper considers the sequential planning process of min-max VRPs as two coupled optimization tasks: customer partition for different routes and customer navigation in each route (i.e., partition and navigation). To effectively process min-max VRP instances, we present a novel attention-based Partition-and-Navigation encoder (P&N Encoder) that learns distinct embeddings for partition and navigation. Furthermore, we utilize an inherent symmetry in decoding routes and develop an effective agent-permutation-symmetric (APS) loss function. Experimental results demonstrate that the proposed Decoupling-Partition-Navigation (DPN) method significantly surpasses existing learning-based methods in both single-depot and multi-depot minmax VRPs. Our code is available at 1 Copyright © 2024, The Authors. All rights reserved.

关键词： Sales

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A Robust Constrained Control of Upper-Limb Exoskeleton for Isometric Rehabilitation Exercises

A Robust Constrained Control of Upper-Limb Exoskeleton for I...

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IEEE International Symposium on Industrial Electronics (ISIE)

作者： Matteo Pavia Toshiyuki Murakami Graduate School of Science and Technology Keio University Yokohama Japan DEIB Politecnico di Milano Milan Italy Department of System Design Engineering Keio University Yokohama Japan

ISBN: (数字)9798350394085

ISBN: (纸本)9798350394092

The research field of muscle rehabilitation and strength recovery is constantly evolving with new techniques and assistive devices being proposed every year. In particular, the need of specialised structures and clinicians, the cost of the rehabilitation and the rising numbers of patients among injured athletes and elderly people, are making rehabilitation robotics a cost-effective alternative. In the last years, researchers have mainly focused on proposing assistive devices to be used during the rehabilitation or new techniques, in order to make the whole process more effective. Nonetheless, the accessibility and the cost of most of the treatments, still leaves a lot of room to improve for a more inclusive access. Besides giving the freedom to the patient to carry out the rehabilitation at home, it is crucial to properly choose the exercise according to the muscles which need to be trained and the condition of the subject. Especially for injured athletes and for the elderly, isometric exercises and static strength training are a good solution to prevent stressing the joints and moving the damaged muscles. Hence, this paper aims to introduce a new musculoskeletal-specific design framework for upper-limb isometric exercises, after having evaluated with a Hexagon Distribution (HD) the muscle condition of the subject. In addition, a 2-DOF wearable and lightweight exoskeleton is introduced to maintain the correct posture of the arm while performing the task. Finally a randomized controlled trial (RCT) is conducted with a cohort of different groups to show the effectiveness of the proposed method.

关键词： Training Industrial electronics Costs Exoskeletons Prototypes Muscles Assistive devices

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Tofukasu-derived biochar with interconnected and hierarchical pores for high efficient removal of Cr (Ⅵ)

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Biochar 2023年第1期5卷 1189-1201页

作者： Liang Fang Wei Yang Jianhua Hou kewang Zheng Asif Hussain Yongcai Zhang Zhenhua Hou Xiaozhi Wang School of Environmental Science and Engineering Yangzhou UniversityYangzhou 225000People’s Republic of China Beijing System Design Institute of Electro-Mechanic Engineering Beijing 100005People’s Republic of China Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization Nanjing 210095People’s Republic of China School of Chemistry and Materials Science Hubei Engineering UniversityXiaoganPeople’s Republic of China Jiangxi Xinda Hangke New Materials Technology Co. LtdNanchang 330096People’s Republic of China

Herein,we report the synthesis of interconnected hierarchical pore biochar(HTB)via an ice-templating strategy using bio-waste(tofukasu).The abundance of N-and O-containing functional groups in tofukasu makes it easy to form hydrogen bonds with water molecules and water clusters,resulting in nano-micro structures like ice clusters and snow crystals during freezing *** importantly,tofukasu will be squeezed by micron-scale snow crystals to form coiled sheet-like structures,and its surface and interior will be affected by needle-like ice nanocrystals from several nanometers to tens of nanometers to form transverse groove needles and *** ice crystals are then removed by sublimation with tofukasu,leaving the interconnected pore structure ***,the ice template synthesis strategy endowed the interconnected hierarchical pore structure of HTB with a large specific surface area(SBET,733 m^(2)⋅g^(−1))and hierarchical porosity(30.30%for mesopores/total pore volume ratio),which is significantly higher than the normal dry treated tofukasu biochar(TB),which had a SBET of 436 m^(2)⋅g^(−1) and contained 1.53%*** addition,the sheet-like structure with interconnected pores of HTB favors high exposure of active sites(N-and O-containing functional groups),and a fast electron transport *** a result,HTB had an excellent adsorption capacity of 159.65 mg⋅g^(−1),which is 4.7 times that of typical block biochar of TB(33.89 mg⋅g^(−1))according to Langmuir *** characterization,FTIR and XPS analysis showed that the mechanism of Cr(Ⅵ)removal by HTB included electrostatic attraction,pore filling,reduction and surface complexation.

关键词： Chromium adsorption Tofukasu Ice template Biochar Hierarchical pore structure Mesopores

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Online Distributed Newton Step Algorithm for Multi-agent Optimization Over General Unbalanced Networks

Online Distributed Newton Step Algorithm for Multi-agent Opt...

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International Conference on Control and Automation (ICCA)

作者： Jiayi Wu Yu-Ping Tian School of Automation Hangzhou Dianzi University Hangzhou Zhejiang Province China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen Guangdong Province China

ISBN: (数字)9798350354409

ISBN: (纸本)9798350354416

This paper studies distributed online optimization over multi-agent networks. Agents work together to optimize the global loss function, which can be expressed as the sum of the local loss functions of all agents. All local loss functions change with time, and information about the loss function can only be obtained after the agent has made a decision. For such a scenario, the performance of many current algorithms will be challenged if the communication topology is unbalanced because, in this case, the contribution share of each agent in the optimization process is not equal to its share in the total loss function. We designed a distributed online Newton step algorithm in unbalanced networks, which add an additional auxiliary variable to scale the share of each agent's contribution in the algorithm. The algorithm uses only row-stochastic matrix instead of double stochastic matrix, and guarantees the logarithmic convergence of regret for α-exp concave loss functions. Simulation results show the effectiveness of the proposed algorithm in unbalanced topology.

关键词： Automation Network topology Simulation Convex functions Topology Optimization Convergence

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DC-Side Decoupling Method of DC-link Capacitor Reduction for Single Phase PWM Rectifier

DC-Side Decoupling Method of DC-link Capacitor Reduction for...

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2020 IEEE Sustainable Power and Energy Conference, iSPEC 2020

作者： Wang, Jinxin Renyong, Peng Dai, Kailei Zhang, Zhiqiang Zhang, Ting Zhao, Junjie Chen, Qian Zhang, Jianjian Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Nuclear Power Institute of China Chengdu China

ISBN: (纸本)9781728191645

The integrated charging system of Electric vehicle consists of a single-phase PWM rectifier and a Buck converter. When the single-phase PWM rectifier works with unit power factor, the dc-link voltage contains a large voltage harmonic of twice the grid frequency. Although the output voltage ripple can be controlled within the required range using the proper control of the Buck converter, the second-order harmonic on the dc-link capacitor is inevitable. This paper proposes a de-side decoupling method for the second-order harmonic problem of the dc-link voltage of the integrated charging system. A de-side decoupling half bridge is connected in parallel to absorb the ripple power of twice the grid frequency. This paper analyzes the operating principle of the de-side decoupling half bridge. Based on a theoretical analysis of the topology and the design procedure for controlling system, the proposed converter is designed and simulated. Finally, simulation results are given to verify the method. © 2020 IEEE.

关键词： Pulse width modulation

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