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Anomalous properties of spark plasma sintered boron nitride solids

materials Today 2025年 86卷 42-51页

作者： Biswas, Abhijit Serles, Peter Alvarez, Gustavo A. Schimpf, Jesse Hache, Michel Kong, Jonathan Demingos, Pedro Guerra Yuan, Bo Pieshkov, Tymofii S. Li, Chenxi Puthirath, Anand B. Gao, Bin Gray, Tia Zhang, Xiang Murukeshan, Jishnu Vajtai, Robert Dai, Pengcheng Singh, Chandra Veer Howe, Jane Zou, Yu Martin, Lane W. Clancy, James Patrick Tian, Zhiting Filleter, Tobin Ajayan, Pulickel M. Department of Materials Science and Nanoengineering Rice University HoustonTX77005 United States Department of Mechanical & Industrial Engineering University of Toronto 5 King's College Road TorontoM5S 3G8 Canada Sibley School of Mechanical and Aerospace Engineering Cornell University IthacaNY14853 United States Department of Materials Science and Engineering University of California Berkeley94720 United States Department of Materials Science and Engineering University of Toronto 184 College St TorontoM5S 3E4 Canada Department of Physics and Astronomy McMaster University HamiltonL8S 4M1 Canada Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley94720 United States

Hexagonal boron nitride (h-BN) is a brittle ceramic with a layered structure, however, recent experiments have suggested that inter-layer structural engineering could be key to new structural and functional properties. Here we report the scalable bulk synthesis of high-density crystalline h-BN solids, by using high-temperature spark plasma sintering (SPS) of h-BN powders, which show high values of mechanical strength, ductility, dielectric constant, thermal conductivity, and exceptional neutron radiation shielding capability. Through exhaustive characterizations we reveal that SPS induces non-basal plane crystallinity, twisting of layers, and facilitates inter-grain fusion with a high degree of in-plane alignment across macroscale dimensions, resulting in near-theoretical density and improved properties. Our findings highlight the importance of material design, via new approaches such as layer twisting and interlayer interconnections, to create novel ceramics with properties that could go beyond their intrinsic limits. © 2025

关键词： Ductility

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Environmentally-friendly alkaline ionized water pretreatment and hydrolysis of macroalga via microwave-assisted heating to improve monosaccharide yield for bioethanol production

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Process Safety and Environmental Protection 2024年 189卷 702-713页

作者： Chen, Wei-Hsin Liu, Li-Xuan Khoo, Kuan Shiong Sheen, Herng-Kuang Kwon, Eilhann E. Saravanakumar, Ayyadurai Chang, Jo-Shu Department of Aeronautics and Astronautics National Cheng Kung University Tainan701 Taiwan Research Center for Smart Sustainable Circular Economy Tunghai University Taichung407 Taiwan Department of Mechanical Engineering National Chin-Yi University of Technology Taichung411 Taiwan International Master Degree Program on Energy National Cheng Kung University Tainan701 Taiwan Department of Chemical Engineering and Materials Science Yuan Ze University Taoyuan Taiwan Sugar Business Division Taiwan Sugar Corporation Taiwan701 Taiwan Department of Earth Resources and Environmental Engineering Hanyang University Seoul04763 Korea Republic of Directorate of Research SRM Institute of Science and Technology Chengalpattu District Tamil Nadu Kattankulathur603203 India Department of Chemical Engineering and Materials Science College of Engineering Tunghai University Taichung Taiwan Department of Chemical Engineering National Cheng Kung University Tainan Taiwan

This study synthesizes three sequential steps: pretreatment, acid hydrolysis, and enzyme hydrolysis for bioethanol and hydrochar production from macroalga Gracilaria. The Taguchi method is employed separately in each step to optimize relevant operating factors, aiming to maximize the monosaccharide yield. During pretreatment, environmentally friendly alkaline ionized water is utilized as it does not contain chemical additives. Afterward, microwave-assisted hydrolysis is adopted to enhance the monosaccharide yield of the macroalga for bioenergy production. The results show that the total sugar of Gracilaria undergoing acid hydrolysis alone is 28.72 g‧L−1. The total sugar content after alkaline pretreatment followed by acid hydrolysis is 32.64 g‧L−1, and it increases to 34.76 g‧L−1 after adding enzymes. Meanwhile, the higher heating value of Gracilaria increases from 10.884 MJ‧kg−1 to 12.620 MJ‧kg−1 after undergoing alkaline pretreatment. After the acid and enzyme hydrolysis processes, it increases to 15.164 MJ‧kg−1. The solid biofuel's calorific value increases by 39 % from the three-stage processes. The liquid product combined with Saccharomyces cerevisiae can produce bioethanol, while the produced hydrochar can be used as a solid fuel. This research promotes the development of macroalgal biomass for energy and environmental applications, thereby advancing the circular bioeconomy. © 2024 The Institution of Chemical Engineers

关键词： Ethanol

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Effect of Heat Treatments on Microstructure and mechanical Properties of Fe-Mn-Ni-Al-Gd Shape Memory Alloy

Effect of Heat Treatments on Microstructure and Mechanical P...

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2023 Sharjah International Conference on Physics of Advanced materials, SICPAM 2023

作者： Mustafa, Faisal Egilmez, Mehmet Abuzaid, Wael El-Khatib, Sami Department of Physics American University of Sharjah Sharjah26666 United Arab Emirates Materials Science and Engineering Program American University of Sharjah Sharjah26666 United Arab Emirates Department of Mechanical Engineering American University of Sharjah Sharjah26666 United Arab Emirates

There are significant scientific and industrial efforts to develop and optimize Iron-based shape memory alloys (SMA) such as FeMnNiAl for cost-sensitive applications. This alloy system shows shape memory and superelastic properties across a large temperature range. However, many studies have pointed out the need for rather complex thermo-mechanical treatments for the optimization of the SMA properties. In addition, works considering the effects of alloying on the development of microstructures that are more conducive to pseudo-elasticity in this system remain limited. Hence, systematic studies aiming at the investigation of the microstructural evolution of the FeMnNiAl(Gd) system are of great interest. In this study, solution heat treatment is done to tune the microstructure for optimum mechanical properties. The effect of phase distribution on mechanical properties is investigated at different heat treatments. Whereas cyclic heat treatment induced abnormal grain growth (AGG) in all samples, so large grains were obtained. The phase variation and elemental composition are analyzed by X-ray diffraction and Energy Dispersive Spectroscopy, respectively. The microstructure and phase distribution are observed using Scanning Electron Microscope and then related to the microhardness results. The microstructure has a good correlation with mechanical properties where the fine distribution of phases results in a higher hardness number. © Published under licence by IOP Publishing Ltd.

关键词： Microstructure

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Atomistic modeling and rational design of optothermal tweezers for targeted applications

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Nano Research 2021年第1期14卷 295-303页

作者： Hongru Ding Pavana Siddhartha Kollipara Linhan Lin Yuebing Zheng Walker Department of Mechanical Engineering The University of Texas at AustinAustinTX 78712USA State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China Materials Science&Engineering Program and Texas Materials Institute The University of Texas at AustinAustinTX 78712USA

Optical manipulation of micro/nanoscale objects is of importance in life sciences,colloidal science,and *** tweezers exhibit superior manipulation capability at low optical ***,our implicit understanding of the working mechanism has limited the further applications and innovations of optothermal ***,we present an atomistic view of opto-thermo-electro-mechanic coupling in optothermal tweezers,which enables us to rationally design the tweezers for optimum performance in targeted ***,we have revealed that the non-uniform temperature distribution induces water polarization and charge separation,which creates the thermoelectric field dominating the optothermal *** further design experiments to systematically verify our atomistic *** by our new model,we develop new types of optothermal tweezers of high performance using low-concentrated ***,we demonstrate the use of new tweezers in opto-thermophoretic separation of colloidal particles of the same size based on the difference in their surface charge,which has been challenging for conventional optical *** the atomistic understanding that enables the performance optimization and function expansion,optothermal tweezers will further their impacts.

关键词： optothermal tweezers optical tweezers optical manipulation thermophoresis molecular dynamics simulation

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Na-22 for Safeguarding and Mass Accounting of Molten Salt Systems

Na-22 for Safeguarding and Mass Accounting of Molten Salt Sy...

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2023 Transactions of the American Nuclear Society Winter Conference and Expo, ANS 2023

作者： Zile, Matthew Van Kauffman, Andrew Herminghuysen, Kevin Li, Shelly Simpson, Michael Kandlakunta, Praneeth Cao, Guoping Cao, Lei R. Nuclear Engineering Program Department of Mechanical and Aerospace Engineering Ohio State University United States Nuclear Reactor Laboratory College of Engineering Ohio State University United States Department of Materials Science and Engineering University of Utah.Idaho National Laboratory United States

The Na-22based radioactive tracer dilution (RTD) technique has been previously demonstrated for mass accounting in small quantities of clean molten salt for bench top testing. While the concept of RTD has proven to be a promising method, it has lacked further validation in large-scale quantities and in fuel-bearing salt. Towards that end, two research initiatives are on-going at The Ohio State University (OSU) and Idaho National Laboratory (INL) to address these challenges. Current work at OSU is focused on evaluating the RTD using the full gamma-ray spectrum of fission products produced by irradiating fuel bearing salt, i.e., UCl3-MgCl2-KCl in a 500-kW research reactor. The INL team has successfully demonstrated the RTD for mass determination using an 8-kg LiCl-KCl-UCl3salt for uranium electrorefining and is currentlyseeking to validate the tracer method with large(about 60 kg)molten salt system(bearing fission products) in an oxide reduction (OR) facility for spent nuclear fuel (SNF) reprocessing. © 2023 American Nuclear Society. All rights reserved.

关键词： Fission products

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Electrochemically Modulated Metasurfaces

Electrochemically Modulated Metasurfaces

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2023 Conference on Lasers and Electro-Optics, CLEO 2023

作者： Eaves-Rathert, Janna Kovalik, Elena Ugwu, Chibuzor Fabian Pint, Cary L. Valentine, Jason G. Department of Mechanical Engineering Vanderbilt University NashvilleTN37212 United States Interdisciplinary Materials Science Program Vanderbilt University NashvilleTN37212 United States Department of Mechanical Engineering Iowa State University AmesIA50011 United States

Electrochemical intercalation of lithium in titanium dioxide and silicon-based metasurfaces is used to initiate phase changes in a continuously tunable, reversible, and bistable manner for dynamic control over structu... 详细信息

ISBN: (纸本)9781957171258

关键词： Titanium dioxide

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21-Component compositionally complex ceramics: Discovery of ultrahigh-entropy weberite and fergusonite phases and a pyrochlore–weberite transition

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Journal of Advanced Ceramics 2022年第4期11卷 641-655页

作者： Mingde QIN Heidy VEGA Dawei ZHANG Sarath ADAPA Andrew J.WRIGHT Renkun CHEN Jian LUO Department of Nano Engineering University of California San DiegoLa Jolla 92093USA Department of Chemistry and Biochemistry University of California San DiegoLa Jolla 92093USA Program of Materials Science and Engineering University of California San DiegoLa Jolla 92093USA Department of Mechanical and Aerospace Engineering University of California San DiegoLa Jolla 92093USA

Two new high-entropy ceramics(HECs)in the weberite and fergusonite structures,along with the unexpected formation of ordered pyrochlore phases with ultrahigh-entropy compositions and an abrupt pyrochlore–weberite transition,are discovered in a 21-component oxide *** the Gibbs phase rule allows 21 equilibrium phases,9 out of the 13 compositions examined possess single HEC phases(with ultrahigh ideal configurational entropies:~2.7kB per cation or higher on one sublattice in most cases).Notably,(15RE_(1/15))(Nb_(1/2)Ta_(1/2))O_(4) possess a single monoclinic fergusonite(C2/c)phase,and(15RE_(1/15))_(3)(Nb_(1/2)Ta_(1/2))_(1)O_(7) form a single orthorhombic(C222_(1))weberite phase,where 15RE_(1/15) represents Sc_(1/15)Y_(1/15)La_(1/15)Pr_(1/15)Nd_(1/15)Sm_(1/15)Eu_(1/15)Gd_(1/15)Tb_(1/15)Dy_(1/15)Ho_(1/15)Er_(1/15)Tm_(1/15) Yb_(1/15)Lu_(1/15).Moreover,a series of eight(15RE_(1/15))_(2+x)(Ti_(1/4)Zr_(1/4)Ce_(1/4)Hf_(1/4))_(2−2x)(Nb_(1/2)Ta_(1/2))_(x)O_(7) specimens all exhibit single phases,where a pyrochlore–weberite transition occurs within 0.75

关键词： compositionally complex ceramics high-entropy ceramics(HECs) weberite pyrochlore fergusonite ultrahigh-entropy ceramics many-component ceramics

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A Soft-Robotic Thumb Orthosis Facilitating Individual Assistance of Thumb Joints

A Soft-Robotic Thumb Orthosis Facilitating Individual Assist...

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IEEE International Conference on Soft Robotics (RoboSoft)

作者： Christina Chase-Markopoulou Anoush Sepehri Tania K. Morimoto Michael T. Tolley Department of Mechanical and Aerospace Engineering Department of Surgery Materials Science and Engineering Program University of California San Diego CA USA

ISBN: (数字)9798331520205

ISBN: (纸本)9798331520212

Many wearable soft robotic devices have been developed to assist with spasticity – the increased muscle tone seen in individuals with neurological conditions such as stroke or cerebral palsy. However, these devices typically lack the ability to individually assist multiple degrees of freedom (DOF), which is essential to performing a broad range of daily tasks. To address this need, we developed a soft robotic thumb orthosis to achieve movement in three DOF. We focused on the thumb as it performs the most complex movement. Our orthosis used three unfolding textile pneumatic actuators to assist with the extension of the interphalangeal joint, combined extension of the metacarpal and carpometacarpal joints, and abduction of the carpometacarpal joint. The orthosis was tested on both a 3D-printed biomimetic test bed that emulated spasticity and a healthy individual. The orthosis met the full range of motion targets for each joint, except for the abduction of the carpometacarpal joint with medium spasticity, and surpassed the range of motion threshold required for activities of daily living. The orthosis was able to: (1) assist each DOF independently, (2) move the tip of a biomimetic thumb to a pre-determined target with total error of less than 1.5 cm when actuated with open-loop control, and, (3) provide individual joint assistance to a user with no motor impairment. This research showcases the ability of a soft robotic orthosis to assist movement in simulated spasticity of individual thumb joints and provides an important step towards a platform to study whether independent joint assistance during rehabilitation improves patient outcomes.

关键词： Performance evaluation Pneumatic actuators Biomimetics Thumb Spasticity Soft robotics Muscles Motors Motion control Textiles

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Transport and magnetic properties of Hund's metal CaRuO3 under strain modulation

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Physical Review B 2024年第4期110卷 L041403-L041403页

作者： Zhen Wang Arjyama Bordoloi Zhaoqing Ding Enling Wang Xiaofeng Wu Zeguo Lin Mingyu Yang Chenxu Liu Jinglin Zhou Meng Meng Fang Yang Qinghua Zhang Xiaoran Liu Sobhit Singh Huan-hua Wang Jiandong Guo Beijing National Laboratory for Condensed Matter Physics and School of Nuclear Science and Technology Department of Mechanical Engineering School of Physical Sciences Materials Science Program

We synthesized CaRuO3 (001) thin films on a set of substrates and investigated their electronic and magnetic properties via combining magnetotransport measurements with first-principles density-functional theory calculations. The experimental results indicate that a moderate strain can introduce the Kondo effect in the system, leading to a significant modulation of the non-Fermi liquid behavior. Moreover, when the strain reaches a certain threshold, the system undergoes a metal-semiconductor transition, accompanied by a transition from a nonmagnetic state to a plausible G-type antiferromagnetic state. We attribute the observed phenomena in CaRuO3 to strain-induced disruption of the delicate balance between the itinerant and the local Ru 4d electrons. These findings shed light on the intriguing magnetic and non-Fermi liquid behavior of CaRuO3, systematically tailored by heteroepitaxial strain.

关键词： Density of states Kondo effect Transport phenomena Ruthenates Ultrathin films Density functional calculations Physical deposition Resistivity measurements Strain engineering X-ray diffraction X-ray reflectivity

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In vitro and in vivo study on fine-grained Mg-Zn-RE-Zr alloy as a biodegradeable orthopedic implant produced by friction stir processing

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Bioactive materials 2023年第10期28卷 448-466页

作者： Vasanth C.Shunmugasamy Marwa AbdelGawad Muhammad Umar Sohail Talal Ibrahim Talha Khan Thomas Daniel Seers Bilal Mansoor Mechanical Engineering Program Texas A&M University at QatarEducation CityDohaQatar Department of Mechanical Engineering Texas A&M University3123 TAMUCollege StationTX 77843USA Proteomics Core Weill Cornell MedicineEducation CityDohaQatar Department of Surgery Division of Orthopedic SurgerySidra MedicineDohaQatar Clinical Orthopedic Surgery Weill Cornell MedicineEducation CityDohaQatar Petroleum Engineering Program Texas A&M University at QatarEducation CityDohaQatar Department of Materials Science and Engineering Texas A&M University3003 TAMUCollege StationTX 77843USA

Magnesium alloys containing biocompatible components show tremendous promise for applications as temporary biomedical devices. However, to ensure their safe use as biodegradeable implants, it is essential to control their corrosion rates. In concentrated Mg alloys, a microgalvanic coupling between the α-Mg matrix and secondary precipitates exists which results in increased corrosion rate. To address this challenge, we engineered the microstructure of a biodegradable Mg-Zn-RE-Zr alloy by friction stir processing (FSP), improving its corrosion resistance and mechanical properties simultaneously. The FS processed alloy with refined grains and broken and uniformly distributed secondary precipitates showed a relatively uniform corrosion morphology accompanied with the formation of a stable passive layer on the alloy surface. In vivo corrosion evaluation of the processed alloy in a small animal model showed that the material was well-tolerated with no signs of inflammation or harmful by-products. Remarkably, the processed alloy supported bone until it healed till eight weeks with a low in vivo corrosion rate of 0.7 mm/year. Moreover, we analyzed blood and histology of the critical organs such as liver and kidney, which showed normal functionality and consistent ion and enzyme levels, throughout the 12- week study period. These results demonstrate that the processed Mg-Zn-RE-Zr alloy offers promising potential for osseointegration in bone tissue healing while also exhibiting controlled biodegradability due to its engineered microstructure. The results from the present study will have profound benefit for bone fracture management, particularly in pediatric and elderly patients.

关键词： Biodegradable magnesium Bone healing Friction stir processing Microstructure Corrosion resistance

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