Effect Of Ultrasonic Treatment On The Microstructure And Mechanical Properties Of Al6061 And Composite,
2017
Florida International University
Effect Of Ultrasonic Treatment On The Microstructure And Mechanical Properties Of Al6061 And Composite, Ana S. Exime
FIU Electronic Theses and Dissertations
In this study, the effect of ultrasonic treatment (UST) parameters such as amplitude, sonication time, and melt temperature on microstructure and microhardness of Al 6061 alloy is evaluated. The effect of UST on the dispersion of tungsten disulfide (WS2) and carbon nanotubes (CNT) as reinforcement particles in Al 6061 during casting is also studied. The cast Al 6061 with UST demonstrated 32% grain size reduction and 8% increase in the microhardness for optimum processing conditions. The cavitation process induced by UST is responsible for the refinement in microstructure and increase of hardness by enhancing the degassing and nucleation …
Method For Single Crystal Growth Of Photovoltaic Perovskite Material And Devices,
2017
University of Nebraska-Lincoln
Method For Single Crystal Growth Of Photovoltaic Perovskite Material And Devices, Jinsong Huang, Qingfeng Dong
Department of Mechanical and Materials Engineering: Faculty Publications
Systems and methods for perovskite single crystal growth include using a low temperature solution process that employs a temperature gradient in a perovskite solution in a container , also including at least one small perovskite single crystal , and a substrate in the solution upon which substrate a perovskite crystal nucleates and grows , in part due to the temperature gradient in the solution and in part due to a temperature gradient in the substrate . For example , a top portion of the substrate external to the solution may be cooled .
Computational Studies Of Structure–Function Relationships Of Supported And Unsupported Metal Nanoclusters,
2017
University of Massachusetts Amherst
Computational Studies Of Structure–Function Relationships Of Supported And Unsupported Metal Nanoclusters, Hongbo Shi
Doctoral Dissertations
Fuel cells have been demonstrated to be promising power generation devices to address the current global energy and environmental challenges. One of the many barriers to commercialization is the cost of precious catalysts needed to achieve sufficient power output. Platinum-based materials play an important role as electrocatalysts in energy conversion technologies. In order to improve catalytic efficiency and facilitate rational design and development of new catalysts, structure–function relationships that underpin catalytic activity must be understood at a fundamental level. First, we present a systematic analysis of CO adsorption on Pt nanoclusters in the 0.2-1.5 nm size range with the aim …
Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr,
2017
University of Massachusetts Amherst
Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel
Doctoral Dissertations
A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic …
Oct-Based Three Dimensional Modeling Of Stent Deployment,
2017
University of Nebraska-Lincoln
Oct-Based Three Dimensional Modeling Of Stent Deployment, Pengfei Dong, David Prabhu, David L. Wilson, Hiram G. Bezerra, Linxia Gu
Department of Mechanical and Materials Engineering: Faculty Publications
Stent deployment has been widely used to treat narrowed coronary artery. Its acute outcome in terms of stent under expansion and malapposition depends on the extent and shape of calcifications. However, no clear understanding as to how to quantify or categorize the impact of calcification. We have conducted ex vivo stenting characterized by the optical coherence tomography (OCT). The goal of this work is to capture the ex vivo stent deployment and quantify the effect of calcium morphology on the stenting. A three dimensional model of calcified plaque was reconstructed from ex vivo OCT images. The crimping, balloon expansion and …
Template Induced Fabrication Of Nitrogen Doped Carbon Sheets As Electrode Materials In Supercapacitors,
2017
School of Chemistry and chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
Template Induced Fabrication Of Nitrogen Doped Carbon Sheets As Electrode Materials In Supercapacitors, Tao Huang, Guang-Zhi Tao, Chong-Qing Yang, Deng Lu, Lie Ma, Dong-Qing Wu
Journal of Electrochemistry
Due to the good electrical conductivity, high specific surface area, and excellent chemical/mechanical stability, carbon nanomaterials with two-dimensional morphology have gradually become the hot topic of the research on supercapacitors. Herein, we report for the first time the fabrication of nitrogen doped carbon sheets (NCSs). In our approach, the sheet-like magnisum aluminum (MgAl) layered double hydroxide was used as the hard template, which was mixed with o-phenylene diamine and iron chloride. The following thermal treatment could render the polymerization and carbonization of o-phenylene diamine. The NCSs with ordered hexagonal architectures were formed by final etching process of the thermally treated …
Recent Advances On Carbon And Transition Metallic Compound Electrodes For High-Performance Supercapacitors,
2017
MOE of the Key Laboratory of Bioinorganic and Synthetic Chemistry, KLGHEI of Environment and Energy Chemistry, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, People’s Republic of China;
Recent Advances On Carbon And Transition Metallic Compound Electrodes For High-Performance Supercapacitors, Dun Lin, Xi-Yue Zhang, Yin-Xiang Zeng, Ming-Hao Yu, Xi-Hong Lu, Ye-Xiang Tong
Journal of Electrochemistry
Supercapacitors (SCs) have stimulated intensive interests for their promising applications in electric vehicles and portable electronics, etc. Electrode material is the most important key component of SCs, which vastly determines the performance of SCs. Carbon and transition metallic compound materials have attracted considerable attention and been widely explored as electrode materials. However, the insufficient capacitance of carbon materials and unsatisfactory conductivity and cyclic stability of transition metallic compounds severely limit their implementation as robust SC electrodes. Herein, we highlight our recent efforts to boost the capacitive performance of carbon and metal oxide/nitride electrodes by rationally structural and componential design. The …
Preparation And Characterization Of Cellulose Acetate-Based Separator For Lithium-Ion Batteries,
2017
Coal Engineering College, Shanxi Datong University, Datong 037003, Shanxi, China;
Preparation And Characterization Of Cellulose Acetate-Based Separator For Lithium-Ion Batteries, Hua-Feng Luo, Yuan-Dong Qiao
Journal of Electrochemistry
To improve the electrolyte wettability and thermal resistance of separators used for lithium-ion battery, a novel cellulose acetate (CA)-based separator is facilely prepared by non-solvent induced phase separation (NIPS) wet-process and investigated in lithium-ion batteries. Systematical investigations including morphological characterization, electrolyte wettability and thermal resistance testing were carried out. The results demonstrated that the CA-based separator exhibited well developed three-dimensional porous structures with porosity up to 65%, which is 1.5 times higher than that of PE separator. The CA separator also showed excellent electrolyte uptake (285%) and thermal stability at 150 oC for 30 min. Compared with the commercial …
Strategies To Enhance Energy Density For Supercapacitors,
2017
Laboratory of Clean Energy Chemistry and Materials, State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Lanzhou 730000, P. R. China;
Strategies To Enhance Energy Density For Supercapacitors, Jun-Wei Lang, Xu Zhang, Ru-Tao Wang, Xing-Bin Yan
Journal of Electrochemistry
The biggest advantage of supercapacitor lies in not only the excellent pulse and fast charging-discharging performance, but also the characteristics of long cycle life and wide operating temperature window with no pollution. However, the energy density of supercapacitor is low. In this paper, the working principle, the development status, defects and improvement method of supercapacitors are introduced. Based on the research workes of the supercapacitors with high energy density in our group, combined with the literature reports in recent years, the strategies to promote the energy density of supercarpacitors will be focused. The strategies for the enhancement of energy density …
Porous Carbon Materials Produced By Koh Activation For Supercapacitor Electrodes,
2017
CAS Key Laboratory of Materials for Energy Conversion & Department of Materials Science and Engineering, & iChEM, University of Science and Technology of China, Hefei 230026, P. R. China;
Porous Carbon Materials Produced By Koh Activation For Supercapacitor Electrodes, Jiang-Lin Ye, Yan-Wu Zhu
Journal of Electrochemistry
Porous carbon materials with high specific surface area and excellent conductivity have wide applications in supercapacitor electrodes. Much effort has been made to synthesize and tailor the microstructures of porous carbon materials via various activation procedures (physical and chemical activations). In particular, the chemical activation using potassium hydroxide (KOH) as an activating reagent is promising because of the well-defined micropore size distribution and ultrahigh specific surface area up to 3000 m2·g-1 of the resulting porous carbons. Based mainly on the previous works taken by the authors and collaborators in the field, we have summarized the activation mechanism …
Lithium Ion Hybrid Capacitor With High Energy Density,
2017
Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, PR China;University of Chinese Academy of Sciences, Beijing 100049, PR China;
Lithium Ion Hybrid Capacitor With High Energy Density, Xian-Zhong Sun, Xiong Zhang, Kai Wang, Yan-Wei Ma
Journal of Electrochemistry
Lithium ion hybrid capacitors are electrochemical energy storage devices combining the advantages of both Li-ion battery and electrochemical capacitor. They can be extensively used in many fields. However, the commercialization of lithium ion hybrid capacitor has been encountered several problems, e.g., the device structure design, the screening of materials, the pre-lithiation process, and the interface between electrolyte and electrode, etc. This review summarizes the recent research advances in lithium ion hybrid capacitor with high energy density, including the selection of the active materials in cathode/anode and the separator, the pre-lithiation method using the three-electrode structure, the high- and low-temperature performances, …
Special Issue On Supercapacitors,
2017
College of Materials Science & Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, P. R. China;
Special Issue On Supercapacitors, Xiao-Gang Zhang
Journal of Electrochemistry
Supercapacitors (SCs) have become a new bright spot in electrochemical power source due to their high power density, long cycling life and wide operation temperature. As the high-power density energy storage devices, SCs have been widely applied in electric vehicle, modern communication, aerospace, defense, and many other emerging fields. The markets for SCs are continuously increasing. However, the commercialization of SCs suffers from a lower energy density and higher cost. Thus, one great challenge for the supercapacitor (SC) technology is to improve the energy density without sacrificing the power density and cycle life. To address this critical issue, the worldwide …
Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations,
2017
University of Massachusetts Amherst
Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations, Kaushal Sumaria
Masters Theses
The surface tension of liquid metals is an important and scientifically interesting parameter which affects many metallurgical processes such as casting, welding and melt spinning. Conventional methods for measuring surface tension are difficult to use for molten metals above temperatures of 1000 K. Containerless methods are can be used to measure the surface tension of molten metals above 1000 K. Oscillating drop method is one such method where a levitated droplet is allowed to undergo damped oscillations. Using the Rayleigh’s theory for the oscillation of force-free inviscid spherical droplets, surface tension and viscosity of the sample can be calculated from …
Multiple Scattering Theory For Polycrystalline Materials With Strong Grain Anisotropy: Theoretical Fundamentals And Applications,
2017
University of Nebraska-Lincoln
Multiple Scattering Theory For Polycrystalline Materials With Strong Grain Anisotropy: Theoretical Fundamentals And Applications, Huijing He
Department of Mechanical and Materials Engineering: Faculty Publications
This work is a natural extension of the author’s previous work: “Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation: theoretical fundamentals and applications” (arXiv:1706.09137 [physics.geo-ph]), which established the foundation for developing multiple scattering model for heterogeneous elastic continua with either weak or strong fluctuations in mass density and elastic stiffness. Polycrystalline material is another type of heterogeneous materials that widely exists in nature and extensively used in industry. In this work, the corresponding multiple scattering theory for polycrystalline materials with randomly oriented anisotropic crystallites is developed. To validate the theory, the theoretical results for a series of …
Floating-Gate Transistor Photodetector,
2017
University of Nebraska-Lincoln
Floating-Gate Transistor Photodetector, Jinsong Huang, Yongbo Yuan
Department of Mechanical and Materials Engineering: Faculty Publications
A field effect transistor photodetector that can operate in room temperature includes a source electrode , a drain electrode , a channel to allow an electric current to flow between the drain and source electrodes , and a gate electrode to receive a bias voltage for controlling the current in the channel . The photodetector includes a light - absorbing mate rial that absorbs light and traps electric charges . The light absorbing material is configured to generate one or more charges upon absorbing light having a wavelength within a specified range and to hold the one or more charges …
Datumate,
2017
Construction Engineering & Management, Purdue University
Datumate, Purdue Ect Team
ECT Fact Sheets
Datumate is digitally transforming civil engineering processes used in construction, surveying and infrastructure inspection markets with fully automated, highly precise, cost effective and safe tools. It utilizes state-of-the-art image processing and advanced drones and camera technologies dramatically reducing the amount of time surveying crews spend in the field, speeding up construction progress checks and shortening infrastructure inspection duration, while maintaining survey grade accuracy. The intuitive, simple and automated solutions increase productivity by saving field and office time in civil engineering and inspection projects of roads, intersections, stockpile volumes, topography, piping, industrial facilities, bridges, property surveys, building facades, railways, cellular infrastructure …
Incorporating Student Reflection Into Engineering Courses,
2017
Michigan Technological University
Incorporating Student Reflection Into Engineering Courses, Nancy Barr
TechTalks
Critical reflection as students move through their disciplinary curriculum is one way to cultivate capacity for critical thinking. By embedding opportunities for critical reflection in disciplinary courses, educators can combine aspects of writing theory, metacognitive learning, and critical pedagogy to help students begin to frame how they will apply their skills and talents to problems effecting diverse populations. The new undergraduate ME curriculum combines applied learning and project-based learning methods in a series of four ME Practice courses. Technical communication instruction is also embedded in these courses, and the “capstone” of each course is a reflective essay. By responding to …
Space Mining Is Almost Here!,
2017
Michigan Technological University
Space Mining Is Almost Here!, Paul Van Susant
TechTalks
When going to the Moon and Mars for extended stays with humans it is required to minimize mass by "living off the land" as soon as possible. Mining local resources and using them to produce consumables and construct simple structures can leverage launch mass to the surface of those bodies. In addition, asteroid mining will be able to provide rocket fuel to further spur economic development in CIS-Lunar space and further open up solar system activities. I am working on mining on Mars and the Moon as well as construction using local rocks.
New Concepts In Evolutionary Algorithms For Systems Architecture Optimization,
2017
Michigan Technological University
New Concepts In Evolutionary Algorithms For Systems Architecture Optimization, Ossama Abdelkhalik
TechTalks
This talk will present recent developments in evolutionary algorithms that focus on the systems architecture optimization. One challenge in systems optimization is the variable number of design variables. Three new concepts will be presented in this talk that enable evolutionary algorithms to handle this type of problems more efficiently. The first is the biologically inspired concept of Hidden Genes that implements tags to cover/uncover genes in the variables' code, which enable handling variable number of variables in evolutionary algorithms. The second concept is a structured chromosome approach that transcripts the variables in a multi-layer code as opposed to the standard …
3d Printing Of 316l Stainless Steel And Its Effect On Microstructure And Mechanical Properties,
2017
Montana Tech
3d Printing Of 316l Stainless Steel And Its Effect On Microstructure And Mechanical Properties, Rawn Penn
Graduate Theses & Non-Theses
Laser powder bed fusion or 3D printing is a potential candidate for net shape forming and manufacturing complex shapes. Understanding of how various parameters affect build quality is necessary. Specimens were made from 316L stainless steel at 0°, 30°, 60°, and 90° angles measured from the build plate. Three tensile and four fatigue specimens at each angle were produced. Fracture morphology investigation was performed to determine the fracture mode of specimens at each build angle. Microstructural analysis was performed on one of each orientation. The average grain size of the samples was marginally influenced by the build angle orientation. Tensile …
