Materials Science and Engineering Commons^™

Stress Singularity Study Of Functionally Graded Material Based On Coherent Gradient Sensing Method, Jinjun Zhang

Kevin Lee

Characterization And Modeling To Design And Develop Tailored-Property Filled Glass Composites, Kevin Ewsuk

Composites at Lake Louise (CALL 2015)

Particle-filled-glass composites (FGCs) are being developed as new materials with structure and properties engineered for materials joining (e.g., for solid oxide fuel cells). Relative to conventional sealing glasses used to make hermetic glass-to-metal (GtM) seals, FGCs with tailored properties offer significant potential as more crack resistant hermetic seals with better performance and reliability. Additionally, compared to process sensitive crystallizable glasses, FGCs offer broader processing latitude and robustness, and afford greater control of seal microstructure and properties. FGCs are being developed using a combination of fundamental materials science and materials engineering, employing: 1) experimentally-validated molecular modeling to better understand and ...

Composite Metallic Nanofoam Structures, David Bahr, Matthew Howard, Mohamad Zbib, Raheleh Rahimi, John Balk

Composites at Lake Louise (CALL 2015)

Metallic nanofoams made of metals such as nickel (Ni) or gold (Au) with ligament sizes on the order of 10’s to 100’s of nm’s exhibit several remarkable properties as a consequence of their low relative density and high specific surface area, such as outstanding strength to weight ratios, enhanced plasmonic behavior and size-effect-enhanced catalytic behavior. However, these metallic nanofoams suffer from macroscopically brittle behavior due to plastic deformation in individual ligaments. With little or no barriers for slip, work-hardening is not possible within ligaments and extremely localized plasticity, once initiated, leads to a few ligaments necking and ...

Powerful Artificial Muscles For Morphing Composites And Other Applications, Ray Baughman

Composites at Lake Louise (CALL 2015)

Three successive generations of twist-spun artificial muscles are described and used to make morphing composites and textiles that are electrically, thermally, or chemically powered.¹ Our first generation of twist-spun muscles, which are electrochemically powered by volume changes induced by double-layer charge injection, provide torsional rotation speeds of 590 rpm, and torsional strokes of 250° per millimeter of actuator length, which is 1000 times that for earlier artificial muscles. Our second generation muscles, which require no electrolyte and are based on guest-infiltrated carbon nanotube yarns, can torsionally actuate at 11,500 rpm and deliver 85 times higher power density during ...

Deterministic Three-Dimensional Composite Structures For Energy Storage, Paul Brown

Composites at Lake Louise (CALL 2015)

Through mesoscale design of a 3D current collector, high power density and high energy density primary and secondary (rechargeable) large format and microbatteries (Figure 1) were fabricated. At the most fundamental level, mesostructuring enables optimization of the trade-off between energy and power density in energy storage systems due to unavoidable ohmic and other losses that occur during charge or discharge. Of course, it is at fast charge and discharge, where these effects are most important. By efficient design of the ion and electron transport pathways, we and others have shown it is possible to significantly improve the power-energy relationship. We ...

Diffusion-Based Deformation In Elevated Temperature Micropillar Compression Of Mg-Nb Multilayers, Keith Thomas, Juri Wehrs, Siddharta Pathak, Johann Michler

Nanomechanical Testing in Materials Research and Development V

multilayer, elevated-temperature, micropillar compression

Indentation Behavior Of Superelastic Hard Carbon, Olga Chernogorova, Ekaterina Drozdova, Iraida Ushakova, Evgenii Ekimov, Vicente Benavides, Aleksander Soldatov

Nanomechanical Testing in Materials Research and Development V

Supererlastic hard carbon particles up to 1 mmin size were produced by fullerene collapse upon high-pressure high-temperature treatment with simultaneous sintering of metal-matrix composite materials (CM) reinforced by such particles. The hardness of carbon particles can be varied in a wide range by changing the parameters of their structure, which consists of curved graphene planes or their packets of different sizes. Such carbon phase was called “nanoclusterd graphene phase” (NGP) [1]. The properties of the carbon particles were controlled by changing treatment pressure (5 and 8 GPa) and temperature (1100-1800 K), composition of parent fullerites (C60 or C60/70), and ...

Numerical Studies For Improving Fracture Toughness Resistance Curve Testing Using Single-Edge (Notched) Tension Specimens, Yifan Huang

Electronic Thesis and Dissertation Repository

The fracture toughness resistance curve, i.e. the J-integral resistance curve (J-R curve) or the crack tip opening displacement resistance (CTOD-R) curves, is widely used in the integrity assessment and strain-based design of energy pipelines with respect to planar defects (i.e. cracks). This thesis deals with issues related to the experimental determination of the J(CTOD)-R curves using the newly-developed single-edge (notched) tension (SE(T)) specimens. In the first study, the plastic geometry factor, i.e. the η_pl factor, used to evaluate J in a J-R curve test based on the SE(T ...

Thermal Damage Approach Of Concrete: Application To Specimens Subjected To Combined Compressive And High Temperature Loads, Abdellah Menou, Ghassan Mounajed, Hocine Boussa, Christian La Borderie, Khalid Lafdi

Khalid Lafdi

Within the framework of study of concrete structures subjected to fire, .a theoretical and experimental work was conducted. The aim of this study was to investigate and to model the damage mechanisms of concrete after their exposure to high temperatures. The multiphase Digital Concrete Model as well as the damage model, MOD EV, which were both implemented on the finiteelem~ rit software package, SYMPHONIE, were used simμltaneously to assess the thermal damage of the concrete. In order to validate the thermal damage model, an experimental investigation was performed. The mechanical characteristics of 5 cementitious materials, which included cement paste, mortar ...

Koh Etching Of (100) Si Wafer, No 2, Inayat Bajwa

Protocols and Reports

This report describes KOH etching of (100) Si wafer through a hard mask of silicon oxide, and reveals that the scattered etch rate is ascribed to the etch rates of the different crystal planes exposed during the etching.

Gc Verification Of The Spacecraft Atmosphere Monitor, Jessica S. Castro, Richard D. Kidd, Jeffrey D. Hein

STAR (STEM Teacher and Researcher) Program Posters

International Space Station crew members face the unique challenge of maintaining air quality due to the volatile organic compounds (VOCs) that have the potential to accumulate at unsafe levels. The Spacecraft Atmosphere Monitor (SAM) is a miniature gas chromatograph/mass spectrometer (GCMS) designed to measure major constituents (such as N₂, O₂ and CO₂) and trace VOCs within the cabin of the spacecraft. The gas chromatograph is responsible for separating the sample into its components in order to be characterized. The oven of the gas chromatograph must reach a temperature of 150°C in order to heat constituents ...

A Comparison Of The Elastic Properties Of Graphene- And Fullerene-Reinforced Polymer Composites: The Role Of Filler Morphology And Size, Chang-Tsan Lu, Asanka Weerasinghe, Dimitrios Maroudas, Ashwin Ramasubramaniam

Mechanical and Industrial Engineering Faculty Publication Series

No abstract provided.

A Comparison Of The Elastic Properties Of Graphene- And Fullerene-Reinforced Polymer Composites: The Role Of Filler Morphology And Size, Chang-Tsan Lu, Asanka Weerasinghe, Dimitrios Maroudas, Ashwin Ramasubramaniam

Ashwin Ramasubramaniam

No abstract provided.

A Comparative Study Of Three Different Chemical Vapor Deposition Techniques Of Carbon Nanotube Growth On Diamond Films, Betty T. Quinton, Paul N. Barnes, Chakrapani V. Varanasi, Bang-Hung Tsao, Kevin J. Yost, Sharmila M. Mukhopadhyay

Sharmila M. Mukhopadhyay

This paper compares between the methods of growing carbon nanotubes (CNTs) on diamond substrates and evaluates the quality of the CNTs and the interfacial strength. One potential application for these materials is a heat sink/spreader for high-power electronic devices. The CNTs and diamond substrates have a significantly higher specific thermal conductivity than traditional heat sink/spreader materials making them good replacement candidates. Only limited research has been performed on these CNT/diamond structures and their suitability of different growth methods. This study investigates three potential chemical vapor deposition (CVD) techniques for growing CNTs on diamond: thermal CVD (T-CVD), microwave ...

Carbon Nanotube Based Groundwater Remediation: The Case Of Trichloroethylene, Kshitij C. Jha, Zhuonan Liu, Hema Vijwani, Mallikarjuna Nadagouda, Sharmila M. Mukhopadhyay, Mesfin Tsige

Sharmila M. Mukhopadhyay

Adsorption of chlorinated organic contaminants (COCs) on carbon nanotubes (CNTs) has been gaining ground as a remedial platform for groundwater treatment. Applications depend on our mechanistic understanding of COC adsorption on CNTs. This paper lays out the nature of competing interactions at play in hybrid, membrane, and pure CNT based systems and presents results with the perspective of existing gaps in design strategies. First, current remediation approaches to trichloroethylene (TCE), the most ubiquitous of the COCs, is presented along with examination of forces contributing to adsorption of analogous contaminants at the molecular level. Second, we present results on TCE adsorption ...

Novel Platform Development Using An Assembly Of Carbon Nanotube, Nanogold And Immobilized Rna Capture Element Towards Rapid, Selective Sensing Of Bacteria, Elizabeth I. Maurer, Kristen K. Comfort, Saber M. Hussain, John J. Schlager, Sharmila M. Mukhopadhyay

Sharmila M. Mukhopadhyay

This study examines the creation of a nano-featured biosensor platform designed for the rapid and selective detection of the bacterium Escherichia coli. The foundation of this sensor is carbon nanotubes decorated with gold nanoparticles that are modified with a specific, surface adherent ribonucleic acid (RNA) sequence element. The multi-step sensor assembly was accomplished by growing carbon nanotubes on a graphite substrate, the direct synthesis of gold nanoparticles on the nanotube surface, and the attachment of thiolated RNA to the bound nanoparticles.

The application of the compounded nanomaterials for sensor development has the distinct advantage of retaining the electrical behavior property ...

Nanometal Containing Nanocomposites And Photolithographic Polyaniline Nanofibers, Frank D. Blum, Sunil K. Pillalamarri, Lalani K. Werake, J. Greg Story, Massimo F. Bertino, Akira Tokuhiro

J. Story

There is considerable interest in the use of nanofibers and nanoparticles in electronic devices. These materials have potential application in sensors, actuators, and memory, to name just a few.i,ii the size of the materials used may improve sensitivity because of their high specific surface areas. The nanoparticles may also have properties that are inherently different from their bulk counterparts. The use of synthetic polymers may result in considerable mass savings over conventional metal-based systems. It is clear that these systems have many potential advantages, however, there is still a great deal to be learned about how to make ...

Ce3+ -Ion-Induced Visible-Light Photocatalytic Degradation And Electrochemical Activity Of Zno/Ceo2 Nanocomposite, Mohammad Mansoob Khan Dr, R. Saravanan

Dr. Mohammad Mansoob Khan

Asymmetric Mass Acquisition In Labi: Topological Semimetal Candidate, Yun Wu, Tai Kong, Lin-Lin Wang, Duane D. Johnson, Daixiang Mou, Lunan Huang, Benjamin Schrunk, Sergey L. Bud'ko, Paul C. Canfield, Adam Kaminski

Ames Laboratory Publications

We use our high resolution He-lamp-based, tunable laser-based angle-resolved photoemission spectroscopy measurements and density functional theory calculations to study the electronic properties of LaBi, a binary system that was proposed to be a member of a new family of topological semimetals. Both bulk and surface bands are present in the spectra. The dispersion of the surface state is highly unusual. It resembles a Dirac cone, but upon closer inspection we can clearly detect an energy gap. The bottom band follows roughly a parabolic dispersion. The dispersion of the top band remains very linear, “V” -shape like, with the tip approaching ...

Silk As A Biomaterial Paste For Biomimetic Composite, Sang Hyun Park

Engineering and Applied Science Theses & Dissertations

Silk is a highly promising biomaterial with unique bio-physicochemical properties, such as excellent mechanical and optical properties, biocompatibility and programmable biodegradability. Among many different types, silk from domesticated silkworm, bombyx mori has received wide attention owing to its availability in virtually unlimited quantities and ease of extraction. In this study, we investigated silkworm silk as a protein glue to realize nacre-like composites. We have employed spin assisted layer-by-layer technique to fabricate ultrathin free-standing biocomposite films. Two different composites have been studied: (i) graphene oxide (GO)/silk and (ii) chitin/silk. From our prior work, it is known that the adsorption ...