Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 120 for “"material composition"”.
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MRI Quantification of Cortical Bone Microstructure and Material Composition with Ultrashort Echo Time Sequences
… assessment of cortical bone structure and material composition provides additional information about bone health beyond conventional radiographic assessment of bone mineral density (BMD). Large prospective studies have found that cortical bone imaging biomarkers are associated with …
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Rational manipulation of substrate-supported graphene by heterogeneity of substrate surface and material composition
… devices with a more efficient use of material, or with tailored distribution of surface futures that lead to specific applications. Efficiency gains can be made through use of less material and more controlled spacing of graphene ridges. The immediate impact of this work is most …
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A pneumatic conveying powder delivery system for continuously heterogeneous material deposition in solid freeform fabrication
… (SFF) industry in terms of processes and materials. Fully functional parts are being created directly with little, if any, finishing. Parts are being directly fabricated with engineering materials such as ceramics and metals. This thesis aims to facilitate a substantial advance in rapid …
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Feature-based design of solids with local composition control
… methodology for the design of solids with local composition control (LCC). A suite of composition design features are conceptualized and implemented. The designer can use them singly or in combination, to specify the composition of complex components. Each material composition design feature …
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A study of the static to kinetic friction transition of polymers
… effect of normal load, surface roughness, and material composition on the transition from static to kinetic friction. A double value friction-velocity relationship was found whenever a drop in friction occurred. The material composition seems have a larger effect on friction induced vibrations …
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The Effects of Composition on Weld Solidification Cracking in Low Alloy High Tensile Steels
A study was made of the effects of material composition on weld solidification cracking in the TIG arc welding of thin alloy steel sheet. The main points of this study included the effects of - oxygen, manganese, Mn/S and 0/S ratios on the sulphur induced cracking, and the possibility of predicting …
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A System for High-Throughput Materials Exploration Driven by Machine Learning
Functional materials have vast and high-dimensional compositions spaces which make discovering optimized compositions intractable with conventional synthesis tools. Conventional experimental methods of exploring material composition spaces are slow and resource intensive due to being manual …
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Investigation of Chloride-induced Stress Corrosion Cracking for Long-Term Storage of Spent Nuclear Fuel in Dry Storage Systems
… complex and depends on several factors, such as material composition, exposure temperature, relative humidity, applied tensile stress, and atmospheric salt concentration. An accelerated experiment was designed to simulate marine environments in a controlled fogging chamber to examine 304 and 304L …
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SELECTIVE ADSORPTION OF DIBENZOTHIOPHENES ON ACTIVATED CARBONS WITH METAL SPECIES DEPOSITED ON THEIR SURFACES
… of influence of porosity, surface chemistry, material composition and effects of metals oncarbon adsorbents in desulfurization of liquid fuels. Materials are derived from poly (4-styrenesulfonic acid-co-maleic acid) salts (sodium or transition metals). They are investigated in a dynamic …
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A material segmentation and classification system
In this thesis, I developed a material segmentation and classification system that takes in images of an object and identifies the material composition of the object's surface. The 3D surface is first segmented into regions that likely contain the same material, using color as a heuristic measure. …
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Material Recovery Potential from Solar Photovoltaics: Predictive Modeling and Characterization to Advance the Circular Economy
… capacity will increase the value of key raw materials, underscoring the importance of recycling and movement toward a “circular economy”. However, uncertainties over the quantity and the exact material composition of solar panel waste hamper investments by recyclers, manufacturers, and …
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Knowledge-guided Machine Learning for Sensor-based High-Performance Autonomous Material Characterization
… learning enables sensor-based high-performance material characterization that drives accelerated materials discovery and manufacturing. Traditional materials discovery workflows are driven by low-throughput characterization processes that involve several manual sample preparation steps and …
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Ge and GeSi electroabsorption modulator arrays via strain and composition engineering
… GeSi films on SOI substrates are a suitable materials platform for integrated modulator applications. A modulator's operation wavelength adjustment and its system integration for broadband modulation are two major challenges of fabricating on-chip modulator arrays for telecommunication. …
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Electrodynamic Green's Functions in Layered Media: Accurate Closed -Form Approximations for Both Electric and Magnetic Sources
… of planar media composed of layers of arbitrary material composition and thickness. Special emphasis was placed on making the computer tool robust to ensure the accuracy of the calculated Green's function over a very broad range of frequencies, thus making it suitable for applications ranging …
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Development of a soft-landing system for space applications
… backscattering surfaces were investigated for materials likely encountered by a descent module. The data suggests that surface material composition and density have limited importance. Hydrogen content influences the shape of the spectra, but it does not interfere with the backscatter peak. The …
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Determining the Mechanical Properties of Lattice Block Structures
… NASA Glenn Research Center has investigated the material properties of lattice block structures cast from a conventional aerospace titanium alloy as well as lattice block structures cast from nickel-titanium shape memory alloy. The lattice block structures for both materials were sectioned into …
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Spec2Fab : a reducer-tuner model for translating specifications to 3D prints
Multi-material 3D printing allows objects to be composed of complex, heterogeneous arrangements of materials. It is often more natural to define a functional goal than to define the material composition of an object. Translating these functional requirements to fabricable 3D prints is still an open …
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Designing nanoparticle self-propulsion With nonequilibrium Casimir physics
… we can expect to achieve for a wide range of materials that are commonly used in nanoparticle manufacturing. We provide a detailed description of the role that particle temperature, material composition, and geometry play in generating thermal self-propulsion forces and use this information to …
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Nonlinear vibration analysis of inflatable dams
… Due to the nature of the applications and the material composition of these structures, a study considering the dynamic response of an inflatable dam is warranted. In this study, the equation of motion for an air-inflated dam is derived, then solved using the Galerkin approximation method. The …
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Plasmon Hybridization in Clusters of Metal Nanoparticles and Magnetic Nanoparticle Oligomers
… to researchers. From the morphology and material composition of individual nanoparticles to background environments tunable in real time to aggregation scheme and spatial arrangement, many avenues for controllably altering the optical properties of metal nanoclusters are being explored. …
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