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SSRN 2024年

作者： Ha, Sangyul Kayani, Saif Haider Lee, Kyungjun Park, Suwon Choi, Hyunjoo Seol, Jae Bok Kim, Jung Gi Sung, Hyokyung Department of Semiconductor Engineering Myongji University Yongin17058 Korea Republic of Korea Institute of Materials Science Changwon51508 Korea Republic of Department of Mechanical Engineering Gachon University Gyeonggi-do 13120 Korea Republic of Department of Materials Science and Engineering Kookmin University Seoul02707 Korea Republic of Department of Materials Engineering and Convergence Technology Gyeongsang National University Jinju52828 Korea Republic of

The nano-precipitates with minimal misfit strengthen Al-Zn-Mg alloys by impeding dislocation motion. However, grain boundary precipitates (GBPs) are known to have a completely incoherent relationship with the matrix, making them less effective in strengthening the alloys. Instead, GBPs are recognized for preoccupying elements such as Zn or Mg, thereby diminishing the quantity of nano-strengthening phases. GBPs significantly influence the deformation and fracture behaviors of Al-Zn-Mg alloys by accelerating stress localization and crack formation. In this study, we investigated how the accumulation of dislocations in the GBP areas leads to stress localization and subsequent cracking, using micropillar tests and crystal plasticity finite element method (CP-FEM) analysis. The dislocation pile-up in the GBPs causes stress localization around the grain boundaries, inducing crack initiation and leading to intergranular fracture. These findings enhance our understanding of the role of GBPs in the deformation and cracking of Al-Zn-Mg alloys and may pave the way for new concepts in managing GBPs. © 2024, The Authors. All rights reserved.

关键词： Zinc alloys

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Micro/nanodevices for assessment and treatment in stomatology and ophthalmology

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Microsystems & Nanoengineering 2021年第1期7卷 1-19页

作者： An’an Sheng Long Lin Jia Zhu Jian Zhuang Jian Li Lingqian Chang Huanyu Cheng The Institute of Single Cell Engineering Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University100191 BeijingChina Department of Stomatology Xiang’An Hospital of Xiamen University361100 XiamenChina School of Stomatology North China University of Science and Technology063210 TangshanChina Institute of Plastic Machinery and Plastic Engineering School of Mechanical and Electrical EngineeringBeijing University of Chemical Technology100029 BeijingChina Department of Engineering Science and Mechanics Pennsylvania State UniversityUniversity ParkPA 16802USA.6 School of Biomedical EngineeringResearch and Engineering Center of Biomedical MaterialsAnhui Medical University230032 HefeiChina

Micro/nanodevices have been widely applied for the real-time monitoring of intracellular activities and the delivery of exogenous substances in the past few *** review focuses on miniaturized micro/nanodevices for assessment and treatment in stomatology and *** first summarize the recent progress in this field by examining the available materials and fabrication techniques,device design principles,mechanisms,and biosafety aspects of micro/*** a discussion of biochemical sensing technology from the cellular level to the tissue level for disease assessment,we then summarize the use of microneedles and other micro/nanodevices in the treatment of oral and ocular diseases and conditions,including oral cancer,eye wrinkles,keratitis,and *** with the identified key challenges,this review concludes with future directions as a small fraction of vast opportunities,calling for joint efforts between clinicians and engineers with diverse backgrounds to help facilitate the rapid development of this burgeoning field in stomatology and ophthalmology.

关键词： treatment directions assessment

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Effect of Intermediate Cooling Rate Normalizing on Microstructure and Creep Rupture Strength of P91 Steel

SSRN

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SSRN 2023年

作者： Wang, Xue Sun, Xiaoxiang Zhang, Kai Du, Chengchao Zhang, Da School of Power and Mechanical Engineering Wuhan University Wuhan430072 China School of Materials Science & Engineering Jiangsu University Zhenjiang212013 China

In this work, the P91 sample bearing intermediate normalizing cooling rate(200 °C/h) was prepared. Its mechanical and creep properties were compared with the air-cooling (2000 °C/h) normalized sample, and the differences of microstructure evolution were also compared by employing OM, SEM/EBSD and TEM/EDS. Results showed: 1. Even though P91 steel could obtain the whole martensitic structure after intermediate cooling rate normalizing, its prior austenitic grains and martensitic laths were coarser than air-cooled one and twin martensite was appearing. Strength and hardness of the slow-cooled P91 steel were somewhat lower than the air-cooled one, but it had much lower toughness because of the formation of twin martensite. 2. After tempering, slow-cooled P91 steel recovered more completely with twin martensite disappearing, more serious dislocation density declining, larger M23C6 size and more intracrystalline M23C6 carbides, but its sub-grain size was similar to the air-cooled one. Its strength and hardness dropped evidently, and were still lower than the air-cooled one, but it witnessed a predominant improvement in toughness. 3. Creep rupture strength of the slow-cooled P91 steel was markedly lower than air-cooled one. The main cause of that was the coarsening and different distributions of M23C6 carbides, which weakened the pinning effect and ultimately resulted in degradation acceleration. Besides, more severe sub-grain polygonization and lower dislocation density could promote significant hardness diminution during creep. © 2023, The Authors. All rights reserved.

关键词： Hardness

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EFFECT OF BALL MILLING ON THE MAGNETIC PERFORMANCE OF STRONTIUM FERRITE (SrFe12O19) POWDERS

EFFECT OF BALL MILLING ON THE MAGNETIC PERFORMANCE OF STRONT...

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SAMPE 2024 Conference and Exhibition

作者： Arigbabowo, Oluwasola K. Hassan, Mehadi Asadollahnejad, Azin Islam, Md Shafikul Price, Holt Geerts, Wilhelmus J. Tate, Jitendra Materials Science Engineering and Commercialization Program Texas State University 601 University Drive San MarcosTX78666 United States Ingram School of Engineering Texas State University 601 University Drive San MarcosTX78666 United States Department of Physics Texas State University 601 University Drive San MarcosTX78666 United States

ISBN: (纸本)9781934551455

The primary advantage of the high energy ball milling (HEBM) process is its ability to synthesize a homogeneous mixture with submicron (up to nanoscale) particle size. This approach is a viable process for particle size reduction and grain refinement of magnetic powders, which affects their domain structure and by extension the resulting magnetic properties. In this research, we designed a 9-ball milling experiment by keeping the rotational speed constant at 300rpm and varying the ball-to-powder ratio of 5:1, 8:1, and 10:1 for 6hrs, 10hrs, and 14hrs milling times. The strontium ferrite magnetic powders subjected to HEBM were analyzed for crystallite size and behavior via XRD, particle size reduction via SEM/ImageJ software/originLabPro, and magnetic performance via powder-based VSM measurement. The magnetic performance of the ball-milled strontium ferrite powders shows a good combination of appreciable increment in the S-values (a ratio of the remanence to saturation magnetization) and a considerable decline in coercivity ( © 2024 Soc. for the Advancement of Material and Process engineering. All rights reserved.

关键词： Grain refinement

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Effects of water salinity and temperature on oil-in-water emulsions stabilized by a nonionic surfactant

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Journal of Molecular Liquids 2024年 414卷

作者： Alanazi, Khalid Mohan, Ram S. Swaroop Kolla, Srinivas Shoham, Ovadia Department of Mechanical Engineering The University of Tulsa TulsaOK74104 United States School of Materials Science and Engineering Oklahoma State University TulsaOK74106 United States McDougall School of Petroleum Engineering The University of Tulsa TulsaOK74104 United States

The goal of this work is to understand the effect of water salinity of three salts- NaCl, CaCl2, and MgCl2- on oil-in-water (O/W) emulsions stabilized by nonionic surfactants such as Tergitol 15-S-7 (T15S7). The study investigates not only the impacts of mixing speed, water salinity, and temperature but also the combined effects of salt and temperature on emulsion stability. All emulsions were created using ExxsolTM D110 and distilled water, with a surfactant concentration of 0.050 % wt. in the water phase. Two oil fractions (10 % and 25 % by volume) were studied, and oil and water separation interfaces were measured using a state-of-the-art apparatus, which can record and scan videos of free liquid separation. According to the experimental findings, at concentrations higher than the surfactant's Critical Micelle Concentration (CMC), neither of the divalent salts affects the surface tension of the aqueous solution. Divalent ions, on the other hand, were found to decrease the surfactant's effectiveness at concentrations lower than the CMC. Conversely, monovalent ions had no effect at low concentrations but further reduced the surface tension at large concentrations. All salts, however, had no effect on the volume of the emulsion for more than 4 h at 25 °C, however at 70 °C, 100 % separation happens in a matter of seconds. Decrease in mixing speed from 2500 RPM to 800 RPM caused the emulsion volume to decrease by at least 72 %. © 2024 Elsevier B.V.

关键词： Nonionic surfactants

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A Multiscale Parametric Study to Drug Delivery Modeling in Stented Arteries

A Multiscale Parametric Study to Drug Delivery Modeling in S...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Dimitrios S. Pleouras Vasileios S. Loukas Georgia S. Karanasiou Anastasia Antonaki Dimitrios I. Fotiadis Antonis I. Sakellarios Dept. of Materials Science and Engineering Unit of Medical Technology and Intelligent Information Systems University of Ioannina Ioannina Greece Dept. of Materials Science and Engineering University of Ioannina Ioannina Greece Dept. of Materials Science and Engineering Unit of Medical Technology and Intelligent Information Systems University of Ioannina Biomedical Resarch Institute FORTH-IMBB Ioannina Greece Dept. of Mechanical and Aeronautics Engineering University of Patras Patras Greece

ISBN: (数字)9798350371499

ISBN: (纸本)9798350371505

The aim of this work is to investigate the dynamic behavior of retinoic acid concentration within the coronary artery, examining its distribution both on the stent and to the lumen and the arterial wall. The study aims to elucidate the effect of various factors, including variations in retinoic acid concentration on the stent, the applied blood flow velocity as boundary condition within the lumen, the polymer layer porosity, the arterial wall porosity and the drug permeability. Through a comprehensive analysis of these factors, this research seeks to advance the understanding of how retinoic acid behaves in the complex environment of the coronary artery, offering valuable insights into potential therapeutic applications and advances in cardiovascular medicine. To do this, a multiscale computational model for drug delivery is employed and applied in a stented arterial segment. 3D reconstruction of the arterial artery was achieved using optical coherence tomography (OCT) and X-ray angiography. The positioning of stent geometry was performed using finite element modeling of stent deployment. The results demonstrate that changes to important parameters of the model lead to significant changes to the drug *** Relevance: The importance of this work is related to the development and design of new coronary stents and potentially consider the patient’s phenotype and provide personalized applications.

关键词： Drugs Solid modeling Three-dimensional displays Phenotypes Lumen Drug delivery Finite element analysis Permeability Polymers Arteries

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Studying the effect of processing parameters on the microstructure, strength, hardness, and corrosion characteristics of friction stir dissimilar welded AA5083 and AA7075 aluminum alloys reinforced with Al-SiC matrix

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Heliyon 2025年第1期11卷 e41362页

作者： Abdeltawab, Noha M. Elshazly, Mohamed Shash, Ahmed Y. El-Sherbiny, M. Department of Mechanical Design and Production Faculty of Engineering Cairo University Giza 12316 Egypt Faculty of Engineering and Materials Science German University in Cairo Cairo Egypt

The complementary properties of corrosion resistance and ballistic resistance of AA5083 and AA7075, respectively, explain the significance of welding these two alloys in the marine armor industry. This study investigates a novel Al-SiC matrix reinforcement with a different SiC weight ratio in dissimilar friction stir welding of the AA5083/AA7075 joint at different transverse and rotational speeds. The study deduced that the novel matrix can play an important role in improving strength and ductility simultaneously. Maximum strength takes place under conditions of 50 % SiC in Al-SiC matrix, 900 rpm rotational speed, and 40 mm/min transverse speed of value 209.8 MPa, which is equal to 90 % strength of the base metal AA5083, and the maximum strain takes place at 25 % SiC in Al-SiC matrix, 900 rpm rotational speed, and 20 mm/min transverse speed, with improved strain by 2 % than the softer alloy AA5083. Corrosion weight loss decreased by increasing the SiC weight ratio in the Al-SiC matrix, where it improved by 47.9 % compared to the base metal alloy of AA5083 at 75 % SiC in the Al-SiC matrix, 900 rpm rotational speed, and 20 mm/min transverse speed. © 2024 The Authors

关键词： AA5083/AA7075 welding Aluminum silicon carbide matrix Dissimilar friction stir welding Processing parameters

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Unveiling Processing–Property Relationships in Laser Powder Bed Fusion: The Synergy of Machine Learning and High-throughput Experiments

arXiv

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arXiv 2024年

作者： Amiri, Mahsa Foumani, Zahra Zanjani Cao, Penghui Valdevit, Lorenzo Bostanabad, Ramin Materials and Manufacturing Technology Program University of California IrvineCA92697 United States Department of Mechanical and Aerospace Engineering University of California IrvineCA92697 United States Department of Materials Science and Engineering University of California IrvineCA92697 United States Department of Civil and Environmental Engineering University of California IrvineCA92697 United States

Achieving desired mechanical properties in additive manufacturing requires many experiments and a well-defined design framework becomes crucial in reducing trials and conserving resources. Here, we propose a methodology embracing the synergy between high-throughput (HT) experimentation and hierarchical machine learning (ML) to unveil the complex relationships between a large set of process parameters in Laser Powder Bed Fusion (LPBF) and selected mechanical properties (tensile strength and ductility). The HT method envisions the fabrication of small samples for rapid automated hardness and porosity characterization, and a smaller set of tensile specimens for more labor-intensive direct measurement of yield strength and ductility. The ML approach is based on a sequential application of Gaussian processes (GPs) where the correlations between process parameters and hardness/porosity are first learnt and subsequently adopted by the GPs that relate strength and ductility to process parameters. Finally, an optimization scheme is devised that leverages these GPs to identify the processing parameters that maximize combinations of strength and ductility. By founding the learning on larger "easy-to-collect" and smaller "labor-intensive" data, we reduce the reliance on expensive characterization and enable exploration of a large processing space. Our approach is material-agnostic and herein we demonstrate its application on 17-4PH stainless steel. © 2024, CC BY.

关键词： Global positioning system

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Effect of High-Flow Nasal Cannula on Capnogram Waveform for Studying Non-Invasive Human Ventilation

Effect of High-Flow Nasal Cannula on Capnogram Waveform for ...

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Biomedical engineering Conference (NBEC), IEEE National

作者： Tjokorda Gde Tirta Nindhia Nursyasa Aqila Mohammed Julia Jais Jamaludin Pagupathi Devandran Nabiel Rafa Angel Bhaswara Thalitakum Hutajulu M.B. Malarvili Study Program of Mechanical Engineering Engineering Faculty Udayana University Jimbaran Bali Indonesia School of Biomedical and Health Science Engineering Universiti Teknologi Malaysia Johor Malaysia

This study is conducted to compare three different cannulas; all purpose nasal cannula with 2 prongs, nasal pressure cannula with 2 prongs and single port nasal cannula which are commonly used for capnography device. These cannulas or sometimes called as nasal prong is connected to the device via nose of subjects studied. This procedure is a part of respiratory study to monitor lungs condition and breathing pattern. This study involves 47 subject where the exhaled breath was recorded to make comparison and choose the most suitable and effective for capnography waveform analysis. Utilizing Statistical Package for the Social sciences (SPSS) to find the normality of all the nasal cannula data based on capnogram waveform. The result from the analysis shows that the frequency distribution for type 1 nasal cannula which is also known as all-purpose nasal cannula had the feature values closer to the standard value. Our study proofs that all purpose nasal cannula sampling is the most suitable to capture exhaled breath for monitoring respiratory conditions.

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Enhanced functional reversibility in lead-free ferroelectric material over long cycle pyroelectric energy conversion

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Physical Review materials 2023年第6期7卷 064408-064408页

作者： Chenbo Zhang Zeyuan Zhu Ka Hung Chan Ruhao Huang Xian Chen MOE Key Laboratory of Advanced Micro-Structured Materials School of Physics Science and Engineering Institute for Advanced Study Tongji University Shanghai 200092 China Department of Mechanical and Aerospace Engineering Hong Kong University of Science and Technology Kowloon Hong Kong

The ferroelectric material usually exhibits temperature-dependent spontaneous polarization, known as pyroelectricity, which can be used to directly convert thermal energy to electricity from ambient low-grade waste heat. When utilizing the structural phase transformations of the material, the conversion capability can be magnified, consequently the device performance can be strongly boosted by orders of magnitude. However, common ferroelectric oxides suffer mechanical fatigue and functional degradation over cyclic phase transformations, hindering widespread applications of the energy conversion device. In this paper, we investigate the mechanical and functional reversibility of the material by lattice tuning and grain coarsening. We discover the lead-free compound Ba(Ce0.005Zr0.005)Ti0.99O3−0.10(Ba0.7Ca0.3)TiO3 (BaCeZrTiO3−0.10BaCaTiO3) satisfying the compatibility condition among all present phases by its lattice parameters, making the phase transformations highly reversible. We demonstrated that the energy conversion device with equiaxial coarse grains exhibits exceptional fatigue resistance, with stable pyroelectric current output at 4µA/cm2 over 3000 energy conversion cycles. Our work opens another way to fabricate high-performance materials that advances the pyroelectric energy conversion for practical applications in engineering.

关键词： Ferroelectricity Pyroelectricity Solid-solid transformations Structural properties

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