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A Highly Ductile Composite of 3D-Printed Poly(Lactic Acid)With InSe Particles and Flakes as a

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SmartMat 2025年第1期6卷 155-163页

作者： Huihui Li:!Zhongiang YuI Bowen Liu-|Yang Gao-+|Ming Liu-I Jianqi Zhang-|Rodney SRuoffiD Bin Wang iD ICAS Key Laboratory of Nanosystem and Hierarchical Fabrication National Center for Nanoscience and Technology(NCNST)BeijingChina I 2Tianjin Key Laboratory of Molecular Optoelectronic SciencesDepartment of ChemistrySchool of SciencesTianjin UniversityTianjinChina I 3College of Mechanical EngineeringYangzhou UniversityYangzhouChina I*University of Chinese Academy of SciencesBeijingChina I'Center for Multidimensional Carbon Materials(CMCM)Institute for Basic Science(IBS)UlsanRepublic of Korea I°Department of ChemistryUlsan National Institute of Science and Technology(UNIST)UlsanRepublic of Korea I Department of Materials Science and EngineeringUlsan National Institute of Science and Technology(UNIST)UlsanRepublic of Korea I 8School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)UlsanRepublicofKorea

The biodegradable polymer poly(lactic acid)(PLA)is ***-based composites reinforced by indium selenide(InSe)particles or flakes are prepared;each is found to have outstanding *** nanosheets are prepared by sonication of solid InSe in N-methyl pyrrolidone,followed by washing/dispersion in ethanol,and subsequent *** InSe nanosheets,or in separate studies InSe particles,are mixed with PLA to make composite *** PLA composite materials are 3D-printed into“dogbone"samples that are *** optimum dogbone specimen is 1.5 times stronger and 5.5 times tougher than neat PLA specimens prepared in the same *** the best of our knowledge,this concurrent improvement in tensile strength and toughness has not been achieved before in PLA with any fller *** element analysis,together with experimental analysis of(i)fracture surfaces,(ii)the PLA crystal structure,and(ii)the internal structure by micro-CT scanning,suggests that the exceptional mechanical performance is due to the intrinsic properties of InSe and,particularly,the emergence of crack shielding and crack deflection at the interfaces of PLA and InSe *** findings indicate that PLA-InSe composites may offer opportunities to broaden the applications of PLA composites,including as load-bearing materials.

关键词： 3D printing I InSe I PLA composites I strength I toughness

Constitutive Model of Elastic Response for Fe-Tib2 Composites

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SSRN 2022年

作者： Ye, Yicong Ni, Ziqi Huang, Caiming Bai, Shuxin Chen, Qiang Department of Materials Science and Engineering College of Aerospace Science and Engineering National University of Defense Technology Changsha410073 China School of Mechanical and Electrical Engineering Guilin University of Electronic Technology Guilin541004 China

The elastic response of steel-based metal matrix composites to the macroscopic stress was established for revealing the elastic properties at multiscale. The effective elastic constants (EECs) of the Fe-TiB 2 composites were predicted by the constitutive model in this study, including the effective elastic modulus [[EQUATION]] , effective bulk modulus [[EQUATION]] , effective shear modulus [[EQUATION]] , and effective Poisson's ratio [[EQUATION]] . And then, the diffraction elastic constants (DECs) related to the crystal planes ( hkl ), [[EQUATION]] and [[EQUATION]] of the constituents of the composites, were also evaluated based on the multiscale correlation constitutive equations. Compared with experimental values, there was excellent agreement for the EECs of the Fe-TiB 2 composites and reasonable error in DECs of the steel-based matrixes and TiB 2 reinforcement. Furthermore, the multiscale coupling between the EECs and DECs related to elastic response and residual stress was also concerned in this micromechanical model. The internal stress in the TiB 2 reinforcements is higher than the steel-based matrixes at the same applied stress of the composites, which means the desired load transfer has occurred. © 2022, The Authors. All rights reserved.

关键词： Reinforcement

Design and Modeling of a Cable-Driven Hollow Continuum Manipulator

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Design and Modeling of a Cable-Driven Hollow Continuum Manip...

International Conference on Advanced Robotics and Mechatronics (ICARM)

作者： Changchao Sun Rongjie Kang Peikang Yuan Le Chang Xin Dong Shumin Wan Zhibin Song Jian S. Dai Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education School of Mechanical Engineering Tianjin University Tianjin China Department of Mechanical Materials and Manufacturing Engineering University of Nottingham Nottingham U.K. Institute for Robotics Southern University of Science and Technology Shenzhen China

Continuum manipulators (CMs) have redundancy and flexibility and show good adaptability in unstructured environments. Traditional CMs mostly utilize a backbone to provide structural support and produce bending, which limits the internal space. In this paper, an internally hollow CM is designed. The orthogonal segment ensures two bending degrees of freedom in a single module. In this design, each module contains four cables that can be divided into two pairs driven by two motors respectively, forming a closed-loop cable drive mechanism. For each pair of cables, they have different length change when the module bends. Thus, the actuation space of the manipulator is further mapped to the “motor space” to form the complete kinematic model. As the multi-moduled body has motion coupling, kinematic decoupling is achieved through using Bowden tube. Simulated and experimental results show that the CM designed in our work has high structural load capacity and flexible motion ability.

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A Methodology for Obtaining and Validating Parameters for Surface Repairs Using the Pulsed Gmaw Process

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SSRN 2023年

作者： Muñoz Chávez, Jairo José de Souza Lira, Margareth Nascimento Bestard, Guillermo Alvarez da Cruz Payão Filho, João Alfaro, Sadek Crisostomo Absi Post-Graduation Program in Mechatronics Engineering Department of Mechanical Engineering University of Brasilia CEP 70.910-900 Brazil Federal University of Rio de Janeiro Department of Metallurgical and Materials Engineering National Laboratory of Welding Technology Rio de Janeiro RJ Ilha do FundãoCEP 21941-972 Brazil

This study aims to develop a methodology for obtaining and validating surface parameters using the pulsed GMAW process, capable of producing a weld with appropriate geometric properties as a response. For this purpose, profiling was used as a capture tool together with stability analysis algorithms and metallic transfer criteria. The Fast Fourier Transform was used to analyze the intensity of electric current and voltage oscillogram for the delimitation of the most efficient pulse, detachment characteristics, and drop frequency in each analyzed parameter. In parallel, mathematical modelling of the overlapping of welding beads and volume filling simulation was carried out to obtain a repair methodology of satisfactory quality. Such strategies defined a working window with a voltage between 22 V and 28 V and an intensity of electric current between 190 A and 220 A. For the analyzed material, the best response values were at the base intensity of electric current of 80 A, base time of 1.47 ms, drop separator intensity of electric current of 110 A, drop separator time of 0.5 ms, the peak intensity of electric current of 375 A and peak time of 2.2 ms, corresponding to a working frequency of 240 Hz. With this work methodology, using signal analysis and profiling filming, it is possible to adapt the choice of process parameters to any material with energy and cost savings. These techniques are highly efficient and low-cost. In addition, the GMAW-P transfer mode allows quality work with the intensity of electric current values lower than conventional GMAW. © 2023, The Authors. All rights reserved.

关键词： Drops

Microheater hotspot engineering for repeatable multi-level switching in foundry-processed phase change silicon photonics

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arXiv

arXiv 2024年

作者： Sun, Hongyi Lian, Chuanyu Vásquez-Aza, Francis Kari, Sadra Rahimi Huang, Yi-Siou Restelli, Alessandro Vitale, Steven A. Takeuchi, Ichiro Hu, Juejun Youngblood, Nathan Pavlidis, Georges Ríos Ocampo, Carlos A. Department of Materials Science & Engineering University of Maryland College ParkMD20742 United States Institute for Research in Electronics and Applied Physics University of Maryland College ParkMD20742 United States Department of Mechanical Engineering University of Connecticut StorrsCT06269 United States Electrical & Computer Engineering Department The University of Pittsburgh PittsburghPA15213 United States Joint Quantum Institute Department of Physics University of Maryland College ParkMD20742 United States Advanced Materials and Microsystems Group MIT Lincoln Laboratory LexingtonMA02139 United States Department of Materials Science & Engineering MIT CambridgeMA02139 United States

Nonvolatile photonic integrated circuits employing phase change materials have relied either on optical switching mechanisms with precise multi-level control but poor scalability or electrical switching with seamless integration and scalability but mostly limited to a binary response. Recent works have demonstrated electrical multi-level switching;however, they relied on the stochastic nucleation process to achieve partial crystallization with low demonstrated repeatability and cyclability. Here, we re-engineer waveguide-integrated microheaters to achieve precise spatial control of the temperature profile (i.e., hotspot) and, thus, switch deterministic areas of an embedded phase change material cell. We experimentally demonstrate this concept using a variety of foundry-processed doped-silicon microheaters on a silicon-on-insulator platform to trigger multi-step amorphization and reversible switching of Sb2Se3 and Ge2Sb2Se4Te alloys. We further characterize the response of our microheaters using Transient Thermoreflectance Imaging. Our approach combines the deterministic control resulting from a spatially resolved glassy-crystalline distribution with the scalability of electro-thermal switching devices, thus paving the way to reliable multi-level switching towards robust reprogrammable phase-change photonic devices for analog processing and computing. © 2024, CC BY-NC-SA.

关键词： Scalability

Green energy powered - vapor, thermal and UV light assisted disinfection technology

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materials Today: Proceedings 2023年

作者： Kumar Sadasivuni, Kishor Raj Maurya, Muni Talal Houkan, Mohammad Cabibihan, John-John Geetha, Mithra Al-Maadeed, Somaya Che Roslan, Nazreen Adila Ahmad Ruzaidi, Dania Muzamir Mahat, Mohd Center for Advanced Materials Qatar University PO Box 2713 Doha Qatar Department of Mechanical and Industrial Engineering Qatar University PO Box 2713 Doha Qatar Department of Computer Science and Engineering Qatar University PO Box 2713 Doha Qatar Selangor Shah Alam40450 Malaysia

Infectious diseases are responsible for an immense global burden of disease that impacts public health systems and economies worldwide. The rapid increase in the use of protective items has introduced an urge for their reuse and safe dumping to minimize the threat of disease transmission through cross-contamination. The existing disinfection processes are mostly powered with non-renewable energy sources and focus on single disinfecting technology that limits their installation to in-house applications and reduces the degree of disinfection, respectively. Thus there is a need to develop new strategies and innovations powered by renewable energy sources that enhance the degree of disinfection of daily-use objects and curtail the spread of the infection through cross-contamination. The present study reports a smart automatic technology called "REACTIV-FIT". The technology is developed as an exercise bike with a disinfection chamber that efficiently kills viruses, bacteria, and other germs/pathogens. The current developed technology is equipped with three disinfecting protocols in one system. The system is powered by renewable solar energy and utilizes the mechanical energy during exercise into electrical energy using a generator-based mechanism. The portable smart automatic disinfection box embedded in the bike utilizes the synergetic effect of ultraviolet (UV), thermal, and vapor treatment for sterilizing objects. During vapor treatment, the continuous supply of the sterilizing solution is maintained through a storage tank attached to the outer body of the box and can be easily refilled. In the final step of the disinfecting protocol, the objects are exposed to UV-A light having a peak wavelength of 365–370 nm. The automatic disinfection process is powered by renewable solar and mechanical energy during cycling. The developed technology can be installed in schools, offices, and industries, and its renewable energy-powered feature offers installation in parks, tourist

关键词： Disinfection

Flaw Type Dependent Tensile Properties of 316l Stainless Steel Additively Manufactured by Laser Powder Bed Fusion

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SSRN 2022年

作者： Vallejo, Nathalia Diaz Kljestan, Nemanja Ayers, Nicolas Knezevic, Marko Sohn, Yongho Advanced Materials Processing and Analysis Center Department of Materials Science and Engineering University of Central Florida OrlandoFL United States Department of Mechanical Engineering University of New Hampshire Durham NH United States

In this laser powder bed fusion (LPBF) study for 316L stainless steel (316L SS), the laser scan speed was varied to produce samples with keyhole (KH) and lack of fusion (LoF) flaws, each with three levels of density (i.e., > 97%, ~ 98%, and ~ 99%). KH and LoF flaws were characterized by circularity, size, and aspect ratio from extensive image analysis of optical micrographs. The samples were tested in uniaxial tension to correlate the flaw characteristics with yield strength (YS), ultimate tensile strength (UTS), and elongation at failure (EL%). Results showed that the circularity decreased, while the size and aspect ratio increased for both KH and LoF flaws when the laser scan speed (at constant power) deviates from the LPBF parameters that yields nearly fully dense 316L SS. Additional to the influence of the density, the YS and UTS of the samples showed more sensitivity to the LoF than KH, while the EL% was comparable between the two types of flaws when the porosity is below 2%. The difference in mechanical properties for the 316L samples containing KH and LoF flaws with similar density was minimal because of the intrinsically high ductility of the alloy. © 2022, The Authors. All rights reserved.

关键词： Austenitic stainless steel

3D Printing of Nacre-Inspired Structures with Exceptional mechanical and Flame-Retardant Properties

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Research 2022年第2期2022卷 191-202页

作者： Yang Yang Ziyu Wang Qingqing He Xiangjia Li Gengxi Lu Laiming Jjiang Yushun Zeng Brandon Bethers Jie Jin Shuang Lin Siqi Xiao Yizhen Zhu Xianke Wu Wenwu Xu Qiming Wang Yong Chen Department of Mechanical Engincering.San Diego State University 5500 Campanie DriveSar DiegoCA 92182.USA The Institute of Techrrological Sciences Wuhan UniversityWuhan 430072China School for Enginering of MatterTransport and EnergyArizona State Universiy551 E Tyler MallTempe.AZ 85281USA Department of Biomedical Engincering University of Southern alifrnia1042 Downey WayLos AngelesCA 90089USA Epstein Department of Indusria and Systems Engineering University of Southern Califomnia 3715 McClinock AveLos AngelesCA 90089USA ShadeCraft Robotics Inc.Pasadena CA 91105USA Department of Chemical Engineering and Materials Science University of Southen Calfornian925 Bloom WalkLos AngelesCaliformia 90089USA Deparment of Aerospace and Mechanical Engineering University of Southern CaliforniaLos AngelesCA 9008%.USA 9School of Physics and TechnologyWuhan UniversilyWuhan 430072China School of Physics and Technology Wuhan UniversityWuhan 430072China Sonny Aslani Department of Civil and Enwiromental Engineering University of Southern CaliforniaLos AngelesCA 90089USA

Flame-retardant and thermal management structures have attracted great attention duc to the requirement of high-temperature exposure in industrial,aerospace,and thermal power fields,but the development of protoctive fire-retardant structures with complex shapes to fit arbitrary surfaces is still ***,we reported a rotation-blade casting-assisted 3D printing process to fabricate nacre-inspired structures with exceptional mechanical and flame-retardant properties,and the relatedi fundamental mechanisms are studied.3-(Trimethoxysilyl)propyl methacrylate(TMSPMA)modified boron nitride nanoplatelets(BNs)were aligned by rotation-blade casting during the 3D printing process to build the"hrick and mortar"*** 3D printed structures are more lightweight,while having higher fracture toughness than the natural nacre,which is attributed to the crack deflection,aligned BN(a-BNs)bridging,and pull-outs reinforced structures by the covalent bonding between TMSPMA grafted a-BNs and polymer *** conductivity is enhanced by 25.5 times compared with pure polymer and 5.8 times of anisotropy due to the interconnection of a-BNs.3D printed heat-exchange structures with vertically aligned BNs in complex shapes were demonstrated for efficient thermal control of high-power light-emitting diocles.3D printed helmet and armor with a-BNs show exceptional mechanical and fire-retardant properties,demonstrating integrated mechanical and thermal protection.

关键词： toughness exceptional blade

Thermal, Morphological and Structural Characterization Of Cyperus Malaccensis And Graphene Oxide Acting As a Coupling Agent for Future Reinforcement Applications

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SSRN 2023年

作者： de Mendonça Neuba, Lucas Junio, Raí Felipe Pereira Souza, Andressa Teixeira Chaves, Yago Soares Palmeira, Alexandre Alvarenga Tavares, Sheron Lazarus, Benjamin Pereira, Artur Camposo Monteiro, Sergio Neves Military Institute of Engineering - IME Department of Materials Science Praça General Tibúrcio 80 Praia Vermelha Urca RJ Rio de Janeiro22290-270 Brazil Department of Mechanical Engineering University of Rio de Janeiro State Rod. Pres. Dutra Km 298 Polo Industrial Rj Resende27537-000 Brazil Materials Science and Engineering Program University of California 9500 Gilman Drive La Jolla San DiegoCA United States Military Institute of Engineering Brazil

Natural lignocellulosic fibers (NLFs) are currently receiving exponential concern from researchers on employing them as an engineering material. Particularly, they are being applied as a reinforcement for conventional and biodegradable polymer matrices. Due to the fact that NLFs are a renewable resource, environmentally friendly and require less energy for processing. However, they present drawbacks related to their compatibility with the polymer matrix, caused by the difference in the hydrophilic nature of NLFs and the hydrophobic for polymers. Graphene oxide (GO) is becoming extremely interesting when applied as a coupling agent between the fiber-matrix interface. On account of the amphiphilic nature of the nanomaterial. Therefore, the present work focus on the investigation of the seven- islands sedge (Cyperus malaccensis) coated with GO in 0.1% of the weight of the fiber. Thus, make a comparison with the untreated sedge fibers in terms of their thermal behavior, morphological aspect and structural characterization. Based on the TGA/DTG curves, it was possible to verify that the coating has attained better thermal stability properties. While the DSC thermal curves revealed endothermic and exothermic peaks related to the fiber microstructures. The FTIR spectrum validated the presence of bans associated with the GO structure. XRD affirmed an increase in the crystallite size which improves the interface adhesion. At last, SEM images unveiled the effective GO coating on the surface of the natural fiber. © 2023, The Authors. All rights reserved.

关键词： Fibers