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Enhancing hardness in overlapping scanner-based laser area of carbon and tool steel by multi-pin ultrasonic impact peening

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Lasers in Manufacturing and Materials Processing 2022年第3期9卷 292-311页

作者： Lesyk, D.A. Alnusirat, W. Martinez, S. Dzhemelinskyi, V.V. Mordyuk, B.N. Lamikiz, A. Laser Systems and Advanced Technologies Department National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute" 37 Peremohy ave. Kyiv03056 Ukraine Physical Principals for Surface Engineering Department Kurdyumov Institute for Metal Physics NAS of Ukraine 36 Academician Vernadsky Blvd. Kyiv03142 Ukraine Mechanical Engineering and Mechatronics Department West Pomeranian University of Technology 17 Aleja Piastow Szczecin70310 Poland Technical Science Department Al-Balqa Applied University Al-Salt19117 Jordan Aeronautics Advanced Manufacturing Center University of the Basque Country 202 Bizkaia Science and Technology Park Zamudio48170 Spain Mechanical Engineering Department University of the Basque Country Alameda Urquijo S/N Bilbao48013 Spain

The study and prediction of the structure and hardness in the overlapping area during multi-pass laser heat treatment (LHT) is an important issue for the preparation of the technological process and directly affects the choice of the LHT parameters. The scanner-based laser transformation hardening of the AISI 1045 medium carbon steel and AISI D2 high-chromium tool steel was carried out in a continuous mode using a Rofin Sinar FL010 fiber laser and two-dimensional (2D) optical system. The laser multi-tracks with an overlapping scanning beam of 10%, 25%, and 40% were produced. The computer numerical control programs for the scanner-based laser surface hardening of the large-scale metal parts with various overlapping ratios were developed. The experimental results of the overlapping depth and hardness were compared with the heat-affected zone geometry and Vickers hardness measurements. The microstructure in the laser-hardened and laser-tempered areas is studied by optical microscopy. It was revealed that the overlapping ratio should be selected at 20–25% to obtain the overlapping depth of ~ 400 µm for the studied steels. Unlike carbon steel, the required surface hardness is provided in the laser-tempered zone of the tool steel. To increase the surface hardness in the laser-overlapped area, a multi-pin ultrasonic impact treatment was additionally applied. The results indicated that the severe surface plastic deformation provides the required microhardness in the overlapping area for the AISI 1045 carbon steel. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

关键词： Tool steel

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Multi-Robot Planning on Dynamic Topological Graphs using Mixed-Integer programming

arXiv

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arXiv 2023年

作者： Dimmig, Cora A. Wolfe, Kevin C. Moore, Joseph Johns Hopkins University Applied Physics Laboratory LaurelMD20723 United States Department of Mechanical Engineering Johns Hopkins University BaltimoreMD21218 United States

Planning for multi-robot teams in complex environments is a challenging problem, especially when these teams must coordinate to accomplish a common objective. In general, optimal solutions to these planning problems are computationally intractable, since the decision space grows exponentially with the number of robots. In this paper, we present a novel approach for multi-robot planning on topological graphs using mixed-integer programming. Central to our approach is the notion of a dynamic topological graph, where edge weights vary dynamically based on the locations of the robots in the graph. We construct this graph using the critical features of the planning problem and the relationships between robots;we then leverage mixed-integer programming to minimize a shared cost that depends on the paths of all robots through the graph. To improve computational tractability, we formulated our optimization problem with a fully convex relaxation and designed our decision space around eliminating the exponential dependence on the number of robots. We test our approach on a multi-robot reconnaissance scenario, where robots must coordinate to minimize detectability and maximize safety while gathering information. We demonstrate that our approach is able to scale to a series of representative scenarios and is capable of computing optimal coordinated strategic behaviors for autonomous multi-robot teams in seconds. Copyright © 2023, The Authors. All rights reserved.

关键词： Industrial robots

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Using 4D-STEM to Map 3D Morphologies of 2D Materials

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Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 262-263页

作者： Mireles, Adan Shi, Chuqiao Park, Jeongwon Shin, Bongki Sung, Suk Hyun Ophus, Colin Hovden, Robert Kang, Kibum Han, Yimo Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX United States Department of Materials Science and NanoEngineering Rice University Houston TX United States Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology (KAIST) Daejeon South Korea Department of Materials Science and Engineering University of Michigan Ann Arbor MI United States National Center for Electron Microscopy Molecular Foundry Lawrence Berkeley National Laboratory Berkeley CA United States

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Contraction Analysis of Multi-Agent Control for Guaranteed Capture of a Faster Evader

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ASME Letters in Dynamic Systems and Control 2024年第3期4卷 031001页

作者： Rivera-Ortiz, Pillip M. Frommer, Andrew C. Diaz-Mercado, Yancy https://***/029pp9z10Johns Hopkins University Applied Physics LaboratoryThe Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Road Laurel MD 20723 https://***/047s2c258University of Maryland College Park Department of Mechanical Engineering Collaborative Controls and Robotics Laboratory University of Maryland College Park MD 20742

This work presents a verifiable condition for the selection of a sufficient number of pursuers to capture a faster evader. The condition is based on the tracking performance of a multi-agent control scheme. Trajectory tracking results are provided for both the effects of the multi-agent control topology and its execution by the pursuers in the context of input saturation. To that end, nonlinear contraction theory is leveraged because it provides a unifying framework for the analysis of systems subject to bounded disturbances. Monte Carlo simulations are performed to validate the proposed condition for sufficient pursuers selection.

关键词： nonlinear controls Nonlinear systems Simulation results Systems analysis nonlinear systems Control equipment Theorems (Mathematics) Control systems cooperative control pursuit-evasion games Topology networked systems Dynamics (Mechanics) networked control systems Trajectories (physics) Errors Robotics Teams robotics Simulation

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Phase/Interfacial-Engineered Two-Dimensional-Layered WSe2 Films by a Plasma-Assisted Selenization Process: Modulation of Oxygen Vacancies in Resistive Random-Access Memory

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ACS applied Materials and Interfaces 2023年第28期15卷 33858-33867页

作者： Chaudhary, Mayur Shih, Yu-Chuan Tang, Shin-Yi Yang, Tzu-Yi Kuo, Tzu-Wen Chung, Chia-Chen Shen, Ying-Chun Anbalagan, Aswin kumar Lee, Chih-Hao Hou, Tuo-Hung He, Jr-Hau Chueh, Yu-Lun Department of Materials Science and Engineering National Tsing Hua University Hsinchu30013 Taiwan International Intercollegiate Ph.D. Program National Tsing Hua University Hsinchu30013 Taiwan College of Semiconductor Research National Tsing Hua University Hsinchu30013 Taiwan Department of Physics National Sun Yat-Sen University Kaohsiung80424 Taiwan Department of Engineering and System Science National Tsing Hua University Hsinchu30013 Taiwan Department of Electronic Engineering National Yang Ming Chiao Tung University Hsinchu30013 Taiwan Department of Materials Science and Engineering City University of Hong Kong Hong Kong999077 Hong Kong Frontier Research Center on Fundamental and Applied Sciences of Matters National Tsing Hua University Hsinchu30013 Taiwan Semiconductor Research Center Hon Hai Research Institute Taipei11492 Taiwan

Here, we propose phase and interfacial engineering by inserting a functional WO3 layer and selenized it to achieve a 2D-layered WSe2/WO3 heterolayer structure by a plasma-assisted selenization process. The 2D-layered WSe2/WO3 heterolayer was coupled with an Al2O3 film as a resistive switching (RS) layer to form a hybrid structure, with which Pt and W films were used as the top and bottom electrodes, respectively. The device with good uniformity in SET/RESET voltage and high low-/high-resistance window can be obtained by controlling a conversion ratio from a WO3 film to a 2D-layered WSe2 thin film. The Pt/Al2O3/(2D-layered WSe2/WO3)/W structure shows remarkable improvement to the pristine Pt/Al2O3/W and Pt/Al2O3/2D-layered WO3/W in terms of low SET/RESET voltage variability (−20/20)%, multilevel characteristics (uniform LRS/HRS distribution), high on/off ratio (104-105), and retention (∼105 s). The thickness of the obtained WSe2 was tuned at different gas ratios to optimize different 2D-layered WSe2/WO3 (%) ratios, showing a distinctive trend of reduced and uniform SET/RESET voltage variability as 2D-layered WSe2/WO3 (%) changes from 90/10 (%) to 45/55 (%), respectively. The electrical measurements confirm the superior ability of the metallic 1T phase of the 2D-layered WSe2 over the semiconducting 2H phase. Through systemic studies of RS behaviors on the effect of 1T/2H phases and 2D-layered WSe2/WO3 ratios, the low-temperature plasma-assisted selenization offers compatibility with the temperature-limited 3D integration process and also provides much better thickness control over a large area. © 2023 American Chemical Society.

关键词： Aluminum oxide

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Fluorescent Carbon Dots Illuminate Hydrogen Peroxide Detection: A Promising Approach

Fluorescent Carbon Dots Illuminate Hydrogen Peroxide Detecti...

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BioCAS Workshop, IEEE Colombian

作者： Jessica D. Sánchez Fonseca Nicolas J. Bonilla Fajardo Natalia Vargas Perdomo Oscar Julian Perdomo Charry Álvaro D. Orjuela-Cañón Emma Martín Rodriguez Diana C. Rodriguez Burbano Biomedical Engineering Program School of Medicine and Health Sciences Universidad del Rosario Bogotá Colombia Biomedical Engineering Program Colombian School of Engineering Universidad del Rosario Bogotá Colombia Department of Applied Physics Universidad Autónoma de Madrid Madrid Spain

Hydrogen peroxide ($H_{2}O_{2}$) is an oxidant widely used in industrial and biomedical applications that requires a sensitive and selective quantification method. Despite being one of the most used methods for detecting this oxidant, enzyme-based reactions still exhibit low-cost efficiency and pose high environmental hazards. Optical biosensors have emerged as an attractive alternative, offering potential advantages such as rapid response time and ease of operation. Carbon dots (CDs) are a type of carbon-based nanoparticles that are particularly appealing for this purpose because of their low-cost synthesis procedures and favorable chemical and optical properties. In this study, fluorescent CDs were synthesized via a microwave-assisted method using urea, L-histidine, and citric acid as precursors. The optical properties of the CDs were characterized using UV-Vis and fluorescence spectroscopy. The CDs exhibited a fluorescence sensing range between 1 mM to 50 mM, with a limit detection (LOD) for $H_{2}O_{2}$ of 0.1 mM. The selectivity of the CDs was tested in the presence of various interferents, and the results confirmed their potential for further applications, particularly in metabolite quantification and biological processes. Overall, the low-cost synthesis procedure and favorable properties of the CDs make them a promising candidate for $H_{2}O_{2}$ detection and other biosensing applications.

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Heat Transfer Performance of a Heat Sink Using Triply Periodic Minimal Surfaces (TPMS) Structures 9

Heat Transfer Performance of a Heat Sink Using Triply Period...

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9th International Conference on Control, Decision and Information Technologies, CoDIT 2023

作者： Khadiri, Issam El Abouelmajd, Mohamed Zemzami, Maria Hmina, Nabil Lagache, Manuel Al Mangour, Bandar Bahlaoui, Ahmed Arroub, Ismail Belhouideg, Soufiane University Sultan Moulay Slimane Systems Engineering Laboratory Beni-Mellal Morocco University Sultan Moulay Slimane Lprsi Team of Applied Physics and New Technologies Beni Mellal Morocco Sultan Moulay Slimane University Systems Engineering Laboratory Beni-Mellal Morocco Polytech Annecy Chambery Univ. Savoie Symme AnnecyF-74000 France King Fahd University of Petroleum & Minerals Department of Mechanical Engineering Dhahran Saudi Arabia

ISBN: (纸本)9798350311402

Additive manufacturing processes and generative lattice structure are two increasingly popular methods in thermal management applications, particularly in the design and production of heat sinks for electronic devices. In this paper additive manufacturing was used to create heat sinks with lattice structures, specifically triple periodic minimum surfaces (TPMS). Where a conventional pin-fin heat conductor was compared with a heat sink using TPMS lattices, including Gyroid, IWP, and Neovius structures, by evaluating thermal performance. A model was physically simulated to study the thermal performance of the dispersants on the ANSYS software. The results show that the heat sink incorporating TPMS lattices exhibits superior thermal performance than the traditional pin heat sink. The research demonstrates the potential of additive manufacturing to create complex geometries that can improve the thermal dissipation of electronic devices. © 2023 IEEE.

关键词： 3D printing

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Towards End-to-End Structure Solutions from Information-Compromised Diffraction Data via Generative Deep Learning

arXiv

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arXiv 2023年

作者： Guo, Gabe Goldfeder, Judah Lan, Ling Ray, Aniv Yang, Albert Hanming Chen, Boyuan Billinge, Simon J.L. Lipson, Hod Columbia University Department of Computer Science New YorkNY10027 United States Columbia University Department of Applied Physics and Applied Mathematics New YorkNY10027 United States Duke University Department of Mechanical Engineering and Materials Science DurhamNC27708 United States Columbia University Department of Mechanical Engineering New YorkNY10027 United States

The revolution in materials in the past century was built on a knowledge of the atomic arrangements and the structure-property relationship. The sine qua non for obtaining quantitative structural information is single crystal crystallography. However, increasingly we need to solve structures in cases where the information content in our input signal is significantly degraded, for example, due to orientational averaging of grains, finite size effects due to nanostructure, and mixed signals due to sample heterogeneity. Understanding the structure property relationships in such situations is, if anything, more important and insightful, yet we do not have robust approaches for accomplishing it. In principle, machine learning (ML) and deep learning (DL) are promising approaches since they augment information in the degraded input signal with prior knowledge learned from large databases of already known structures. Here we present a novel ML approach, a variational query-based multi-branch deep neural network that has the promise to be a robust but general tool to address this problem end-to-end. We demonstrate the approach on computed powder x-ray diffraction (PXRD), along with partial chemical composition information, as input. We choose as a structural representation a modified electron density we call the Cartesian mapped electron density (CMED), that straightforwardly allows our ML model to learn material structures across different chemistries, symmetries and crystal systems. When evaluated on theoretically simulated data for the cubic and trigonal crystal systems, the system achieves up to 93.4% average similarity with the ground truth on unseen materials, both with known and partially-known chemical composition information, showing great promise for successful structure solution even from degraded and incomplete input data. The approach doesn’t presuppose a crystalline structure and the approach are readily extended to other situations such as nanomaterials and te

关键词： Carrier concentration

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The Application of the Coupled Acoustic-Structural Approach (Casa) Method on the Free Vibration of Submerged Structures

SSRN

引用

SSRN 2023年

作者： Liu, Zhenhui Ullestad, Oskar Engineering Consultancy Department of New Energy Aker Solutions AS Trondheim7435 Norway Department of Mechanical and Marine Engineering Western Norway University of Applied Sciences Haugesund5528 Norway Department of Physics and Technology University of Bergen Bergen5007 Norway

Traditionally, the consideration of the surrounding water during the modal analysis of submerged structures has been done by applying constant added mass factors. This method may lose its accuracy for complicated structures, especially those with bends and multi-plane topology. The present study utilizes the coupled acoustic structural approach (CASA) to obtain natural frequencies on submerged structures. The work compares the simulated CASA results with experimental results. Four experiments with objects with different geometry were chosen;a straight pipe, cantilever plates, stiffened cylindrical shell, and a disk. We found that the CASA method produced accurate results for the three first eigenmodes compared to the experimental results. It could simulate bending, twisting, ovality, and stretching mode shapes with an accuracy of less than 10% difference. Additionally, we applied the CASA method to two submerged jumper structures for the first time. We found that the CASA method gives accurate modal analysis results and is recommended to be used. © 2023, The Authors. All rights reserved.

关键词： Modal analysis

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Calibration free, time-resolved diffuse optical spectroscopy using combined monte-carlo and diffusion theory 11

Calibration free, time-resolved diffuse optical spectroscopy...

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Biomedical Applications of Light Scattering XI 2021

作者： Helton, Michael McMaster, Carter Mycek, Mary-Ann Vishwanath, Karthik Applied Physics Program University of Michigan Ann Arbor United States Department of Physics Miami University OxfordOH45056 United States Biomedical Engineering Department University of Michigan Ann Arbor United States

ISBN: (数字)9781510641501

ISBN: (纸本)9781510641495

Near-infrared spectroscopy has been widely employed in biophotonics to study and quantify the optical properties of biological tissues. Unlike steady-state approaches, time-resolved spectroscopic techniques enable optical absorption and scattering properties of the medium to be separated, allowing for quantitation of depth-dependent absolute tissue optical properties. However, robust analysis of time-resolved signals requires careful consideration of calibration techniques and computational models. Here, we consider the effect of the time window employed when fitting a diffusion theory model to Monte-Carlo simulations. Next, we describe the impact of the temporal position of the instrument response function (IRF) in recovery of the optical properties. Finally, we discuss a technique to analyze time-resolved measurements without knowledge of the timescale of the IRF or the time-resolved measurement byfitting the relative shape of the photons' distribution time-of-flight (DTOF). © 2021 SPIE. All rights reserved.

关键词： Near infrared spectroscopy

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