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Predicting Ion Sequestration in Charged Polymers with the Steepest-Entropy-Ascent Quantum Thermodynamic Framework

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arXiv

arXiv 2023年

作者： McDonald, Jared von Spakovsky, Michael R. Reynolds, William T. Materials Science & Engineering Department Virginia Tech BlacksburgVA24061 United States Mechanical Engineering Department Virginia Tech BlacksburgVA24061 United States

The steepest-entropy-ascent quantum thermodynamic framework is used to investigate the effectiveness of multi-chain polyethyleneimine-methylenephosphonic acid in sequestering rare-earth ions (Eu+3) from aqueous solutions. The framework applies a thermodynamic equation of motion to a discrete energy eigenstructure to model the binding kinetics of europium ions to reactive sites of the polymer chains. The energy eigenstructure is generated using a non-Markovian Monte Carlo model that estimates energy level degeneracies. The equation of motion is used to determine the occupation probability of each energy level, describing the unique path through thermodynamic state space by which the polymer system sequesters rare-earth ions from solution. A second Monte Carlo simulation is conducted to relate the kinetic path in state space to physical descriptors associated with the polymer, including the radius of gyration, tortuosity, and Eu-neighbor distribution functions. These descriptors are used to visualize the evolution of the polymer during the sequestration process. The fraction of sequestered Eu+3 ions depends upon the total energy of the system, with lower energy resulting in higher sequestration. The kinetics of the overall sequestration are dependent on the steepest-entropy-ascent principle used by the equation of motion to generate a unique kinetic path from an initial non-equilibrium state. © 2023, CC BY-NC-ND.

关键词： Entropy

Development of a Life Prediction Model of Ti-6Al-4V obtained by Additive Manufacturing

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Procedia Structural Integrity 2024年 53卷 236-245页

作者： João Alves Teresa Morgado Ivan Galvão António Pereira Manuel Pereira Lisbon School of Engineering of Polytechnic Institute of Lisbon Portugal UNIDEMI - Research & Development Unit in Mechanical and Industrial Engineering Department of Mechanical and Industrial Engineering FCT NOVA - Faculty of Science and Technology Universidade Nova de Lisboa Almada Portugal Intelligent Systems Associate Laboratory Guimarães Portugal Navy Research Center Almada Portugal CEMMPRE – Centre for Mechanical Engineering Materials and Processes Department of Mechanical Engineering University of Coimbra Coimbra Portugal CDRsp & ESTG - Centre for Rapid and Sustainable Product Development & School of Technology and Management of Institute Polytechnic of Leiria Leiria Portugal CERENA- Center of Natural Resources and Environment Univerdade Lisboa Lisboa Portugal

The present study aimed to develop a new life prediction model of a Ti-6Al-4V alloy obtained by additive manufacturing (AM). The Selective Laser Melting (SLM) method was used to obtain specimens. This study contemplates four phases. The first phase encompasses an analysis of the manufacturing process, including the raw materials cycle, specimen design, and the cutting process. In the second phase, tensile and fatigue tests are conducted to obtain the elastic and plastic proprieties and fatigue parameters (S-N Curve). The third phase involves an analytical and quantitative study of the manufacturing intrinsic defects of the SLM process, using optical microscopy, micro and nanotomography, and image treatment. The last phase focused on developing a life prediction model for Ti-6Al-4V based on experimental findings from the preceding steps. In conclusion, Ti-6Al-4V alloy obtained by additive manufacturing showed better overall mechanical properties when compared to the same alloy produced by a traditional method, exhibiting robust plastic behaviour and good ductility. Concerning life prediction models, two new models were developed to predict the fatigue limit of a Ti-6Al-4V obtained by additive manufacturing based on two different defect quantification methods.

关键词： Ti-6Al-4V Additive Manufacturing Selective Laser Melting Life Prediction Modelos Tomography

Design and Dynamic Analysis of a Two-Degree-of-Freedom Pneumatic-Electromagnetic Hybrid Actuator Using Bellows Pneumatic Actuator

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Design and Dynamic Analysis of a Two-Degree-of-Freedom Pneum...

Annual Conference of Industrial Electronics Society

作者： Akira Heya Keita Taki Yoshihiro Nakata Tsuyoshi Inoue Katsuhiro Hirata Department of Mechanical Systems Engineering Nagoya University Nagoya Japan Division of Materials and Manufacturing Science Osaka University Suita Japan Department of Mechanical and Intelligent Systems Engineering The University of Electro-Communications Chofu Japan

Various actuators have been developed to improve the performance of cooperative robots. Multi-degree-of-freedom (multi-DOF) electromagnetic actuators can rotate multi-DOF by a direct drive and can contribute to system miniaturization and higher precision. However, the biggest challenge is to increase the output because the torque cannot be amplified using a reduction gear. To solve this problem, this paper focuses on a hybrid actuation with a pneumatic actuator, which has a large output density. In this study, we propose a two-DOF pneumatic-electromagnetic hybrid actuator that integrates a bellows pneumatic actuator and a two-DOF electromagnetic actuator. First, the concept, design, and operating principle are presented. Next, the torque control method, dynamic model, and attitude control system are shown. In the torque analysis, the maximum torque of the proposed actuator is four times larger compared with a conventional two-DOF electromagnetic actuator of the same size. The dynamic simulation results show that attitude control is possible with hybrid actuation. Based on the results, a hybrid multi-DOF actuator using multiple drive sources is proposed for the first time.

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A Study on Giant Magnetostrictive Actuator for Interior Sound Control System of the Ultra-Compact Mobility: Fundamental Consideration on Formation of the Giant Magnetostrictive Phases Depending on Heat Treatment Condition 27

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A Study on Giant Magnetostrictive Actuator for Interior Soun...

27th International Conference on Electrical Machines and Systems, ICEMS 2024

作者： Kato, Taro Naganuma, Ryusei Bando, Koki Sawada, Kentaro Wenbao, Wu Kobayashi, Ikkei Kuroda, Jumpei Uchino, Daigo Ogawa, Kazuki Ikeda, Keigo Endo, Ayato Kato, Hideaki Narita, Takayoshi Furui, Mitusaki Tokyo University of Technology Department of Mechanical Engineering 1404-1 Katakura Hachioji-shi Tokyo192-0982 Japan Sustainable Engineering Program Graduate School of Engineering Tokyo University of Technology 1404-1 Katakura Hachioji-shi Tokyo192-0982 Japan Tokai University Kitakaname 4-1-1 Kanagawa Hiratsuka-shi259-1292 Japan Tokai University Kitakaname 4-1-1 Kanagawa Hiratsuka-shi259-1292 Japan Numazu College Department of Mechanical Engineering Ohoka 3600 Shizuoka Numazu-shi410-0022 Japan Aichi University of Technology Department of Electronic Robotics 50-2 Manori Nishisako-machi Aichi Gamagori-shi443-0047 Japan Hokkaido University of Science Department of Mechanical Engineering 7-Jo 15-4-1 Maeda Teine Hokkaido Sapporo006-8585 Japan Fukuoka Institute of Technology Department of Electrical Engineering Wajiro Higashi 3-30-1 Higashi-ku Fukuoka Fukuoka-shi811-0295 Japan Tokai University Department of Mechanical System Engineering Kitakaname 4-1-1 Kanagawa Hiratsuka-shi259-1292 Japan

ISBN: (纸本)9784886864406

An active noise control system using giant magnetostrictive actuator has been proposed as a countermeasure for interior noise of the ultra-compact mobilities, which is a new transportation tools. In this paper, as basic research toward the development of the proposed giant magnetostrictive actuator for active noise control, we conduct experiments on the material properties when terbium, dysprosium, and iron powder, which make up the giant magnetostrictive material, are mixed and the heat treatment conditions are changed. In this study, the heat treatment temperature was varied from 800°C to 1100°C in 100°C incrementsbased on the equilibrium state temperature of each material, and the heat treatment time was set in 30-minute increments from 1 hour to 3 hours. As a result, TbFe2 was confirmed after heat treatment at an electric furnace temperature of 1000°C for 3 hours, although its strength was insufficient. © 2024 The Institute of Electrical Engineers of Japan.

关键词： Active noise control

Layer-by-Layer Assembly of Chitosan and Quince Seed Gum Polyelectrolytes as a Ph-Responsive, On-Off Switchable Multilayer Film for Controlled Release of Ibuprofen

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SSRN 2024年

作者： Kaviani, Alireza Pircheraghi, Gholamreza Bagheri, Reza Azizi Saadatlou, Ghazaleh Demirel, A. Levent Department of Materials Science and Engineering Sharif University of Technology P.O. Box: 11365‐9466 Tehran Iran Materials Science & Engineering Graduate Program Koç University Sarıyer Istanbul34450 Turkey Chemistry Department Koç University Sarıyer Istanbul34450 Turkey

Polysaccharide-based multilayer films have shown substantial potential for drug delivery application. Herein, polyelectrolyte multilayers using Chitosan (CS) and Quince seed gum (QSG) are constructed and the effects of assembly pH, salt concentration, and post-assembly pH are systematically investigated. It was evident that both mass per unit area (10000 ng/cm2) and the wet thickness (107.8 nm) after the deposition of 5 bilayers were accurately estimated by viscoelastic model due to the highly swollen state of films. Atomic Force Microscopy (AFM) could feasibly demonstrate the development of globular structures during the layer-by-layer assembly. Ellipsometry analysis showed that the variation assembly pH resulted in conformational changes from extended to coiled. Consequently, different optical thicknesses as well as transitions from exponential to linear growth were observed. Moreover, extrinsic charge compensation was responsible for coiling or extensive counterion screening of polyelectrolyte chains depending on the NaCl concentration. CS/QSG films displayed pH-stimulus on–off switching behavior in pH 2 and 7.4 for 3 cycles. The constructed film could absorb 1200 ng/cm2 within 60 min at pH 7.4. The in vitro release kinetic from IBF-loaded samples showed pH dependency. The CS/QSG multilayer film can be considered as a smart and tunable pH stimuli system for drug loading/release applications. © 2024, The Authors. All rights reserved.

关键词： Chitosan

Corner cutting connects chiral colorimetry to net electric flux in lossless all-dielectric metasurfaces

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arXiv

arXiv 2024年

作者： Haddadin, Zaid Nguyen, Anna M.Y. Poulikakos, Lisa V. Department of Electrical & Computer Engineering UC San Diego La Jolla CA92093-0021 United States Department of Mechanical & Aerospace Engineering UC San Diego La Jolla CA92093-0021 United States Program of Materials Science & Engineering UC San Diego La Jolla CA92093-0021 United States

All-dielectric metasurfaces can produce structural colors, but the most advantageous design criteria are still being investigated. This work numerically studies how the two-dimensional shape of nanoparticles affects the colorimetric response under circularly polarized light (CPL) to develop a sensor distinguishing CPL orientations. Using lossless dielectric materials (silicon nitride on silicon dioxide), we achieve far-field dichroism by modifying oblong nanoparticles into L-shaped structures through corner cuts. This design suppresses one electric dipole under CPL illumination, leading to differential colorimetric responses. We link these responses to a decoupling effect in the near-field net electric flux. Our findings provide design guidelines for all-dielectric, lossless colorimetric sensors of chiral light. Copyright © 2024, The Authors. All rights reserved.

关键词： Silicon nitride

Study on Microstructure and Properties of Aa7075 Coated by Micro Arc Oxidation

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SSRN 2023年

作者： Qi, Xing Jiang, Bo Jiang, Ziqiu Wang, Chao Song, Renguo School of Aeronautics and Mechanical Engineering Changzhou Institute of Technology Jiangsu Changzhou213032 China School of Materials Science and Engineering Changzhou University Jiangsu Changzhou213164 China

Effect of ageing temperature on the properties of 7075 aluminum alloy coated by micro arc oxidation (MAO) technology has been investigated. The precipitates formed during various ageing temperatures are observed by transmission electron microscope (TEM), which would significantly influence the properties of the MAO coating. Coherent distortion, size and volume fraction of precipitates are related to the changing of electrical conductivity during ageing treatment. Full coherent and dense GP zones formed at 90 ℃ can act as scattering centers to impede electron mobility, so decrease the electrical conductivity. η and η’ phases produced at 120 ℃ and 150 ℃ are semi-coherent and incoherent, respectively, meanwhile, the precipitate size increases and the volume fraction decreases with increasing the ageing temperature, therefore, the electrical conductivity increases. Higher electrical conductivity contributes to thicker coating with better surface morphology. Double cantilever beam (DCB) tests show that the thicker and less porous coatings prepared at 150 ℃ aged specimens own the best stress corrosion cracking (SCC) resistance. After pores are broke and coatings are ruptured, high Cu and low Mg segregation at the grain boundary of 150 ℃ aged specimens founded from high-angle annular dark field scanning transmission electron microscopy (HADDF-STEM) are beneficial to anodic dissolution and hydrogen assisted crack. © 2023, The Authors. All rights reserved.

关键词： Morphology

Exploring the Effects of Temperature, Transverse Pressure, and Strain Rate on Axial Tensile Behavior of Pristine Polyethylene Crystals Using Molecular Dynamics

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SSRN 2024年

作者： Dewapriya, M.A. Nuwan Deitzel, Joseph M. Gillespie, John W. Center for Composite Materials University of Delaware NewarkDE United States Department of Materials Science and Engineering University of Delaware NewarkDE United States Department of Mechanical Engineering University of Delaware NewarkDE United States Department of Civil and Environmental Engineering University of Delaware NewarkDE United States

We investigated the influence of temperature, transverse pressure, and strain rate on the axial tensile behavior of pristine polyethylene (PE) crystals using molecular dynamics simulations, considering the combined effects of these parameters. Our findings indicate that elevated temperatures reduce modulus and strength due to thermal vibrations disturbing the crystal structure and increasing kinetic energy. Conversely, transverse pressure enhances properties by improving interchain interactions. As the strain rate increases, modulus and strength increase, reaching a plateau when the loading velocity exceeds the maximum sliding velocity of the broken chains, which occurs around a strain rate of 1012 s-1. These insights into the mechanical response of pristine PE crystals enhance our understanding of ultra-high-molecular-weight polyethylene fiber behavior under realistic service temperatures and impact conditions, with significant implications for designing protective structures such as body armor. © 2024, The Authors. All rights reserved.

关键词： Strain rate

Atomistic Simulations and Machine Learning of Solute Grain Boundary Segregation in Mg Alloys at Finite Temperatures

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SSRN 2023年

作者： Menon, Vaidehi Das, Sambit Gavini, Vikram Qi, Liang Department of Materials Science and Engineering University of Michigan Ann Arbor48109 United States Department of Mechanical Engineering University of Michigan Ann Arbor48109 United States

Understanding solute segregation thermodynamics is first step in investigating grain boundary (GB) properties, such as strong yttrium (Y) effects on grain growth and texture evolution in micro-scale polycrystalline magnesium (Mg) alloys. To estimate average GB segregation behavior of low-concentration Y solutes (e.g., 2 at.%), a state-of-the-art spectral approach is applied based on a per-site segregation energy spectrum for Y solutes at zero K obtained from molecular statistics (MS) simulations of ~104 GB sites in Mg symmetric tilt GBs (STGBs). Although selected MS simulation results are consistent with verifications by density functional theory (DFT) calculations, estimates of average segregation tendencies based on the zero-K energy spectrum deviate from experimental observations. To resolve this problem, thermodynamic integration (TI) methods based on molecular dynamics (MD) simulations are used to determine the per-site segregation free energies of Y at representative GB sites, which show contributions beyond harmonic approximations can be important for certain GB sites at high temperatures. A surrogate model of per-site segregation free energy is constructed from a small set of TI data points using stacking cross-validation regressors and physics-informed descriptors. This model is applied to predict the Y segregation free energy spectra for thousands of GB sites in Mg STGBs with uncertainty quantification. The average segregation tendency predicted by the spectral approach based on the free energy spectra agree well (within the uncertainty range) with experimental observations for micro-scale polycrystalline Mg alloys at typical thermomechanical processing temperatures (500~800K), where thermodynamic equilibrium states are likely to be achieved due to fast diffusion. © 2023, The Authors. All rights reserved.

关键词： Magnesium alloys