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Banerjee, J. R. "Advances in structural dynamics, aeroelasticity and material science." Thesis, City University London, 2015. http://openaccess.city.ac.uk/14901/.
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This submission for the degree of Doctor of Science includes all the publications by the author and a description of his research, covering the period 1969-2015. The main contributions to knowledge made by the author concern his new approaches to structural dynamics, aeroelasticity, material science and related problems. In particular, the major activities of his research relate to the (i) free vibration and buckling analysis of structures, (ii) dynamic stiffness formulation, (iii) response of metallic and composite structures to deterministic and random loads, (iv) aeroelasticity of metallic and composite aircraft, (v) a unified approach to flutter, dynamic stability and response of aircraft, (vi) aeroelastic optimisation and active control, (vii) application of symbolic computation in structural engineering research, (viii) development of software packages for computer aided structural analysis and design and (ix) thermal properties of polymer nanocomposites and hot ductility of steel. The free vibration analysis of structures is a research topic which has been an age old companion of the author ever since he was working for his Master’s degree in Mechanical Engineering in the early 1970s, when he chose a crankshaft vibration problem of the Indian Railways as the research topic for his Master’s thesis. With increasing maturity and experience, he provided solutions to vibration and buckling problems ranging from a simple single structural element to a high capacity transport airliner capable of carrying more than 500 passengers and a large space platform with a plan dimension of more than 30 metres. To provide these solutions, he resorted to an elegant, accurate, but efficient method, called the dynamic stiffness method, which uses the so-called dynamic stiffness matrix of a structural element as the basic building block in the analysis. The author has developed dynamic stiffness matrices of a large number of structural elements including beams, plates and shells with varying degrees of complexity, particularly including those made of composite materials. Recently he published the dynamic stiffness matrices of isotropic and anisotropic rectangular plates for the most general case when the plate boundaries are free at all edges. Computation of natural frequencies of isotropic and anisotropic plates and their assemblies for any boundary conditions in an exact sense has now become possible for the first time as a result of this development. This ground-breaking research has opened up the possibility of developing general purpose computer programs using the dynamic stiffness method for computer-aided structural analysis and design. Such computer programs will be vastly superior to existing computer programs based on the finite element method, both in terms to accuracy and computational efficiency. This is in line with the author’s earlier research on free vibration and buckling analysis of skeletal structures which led to the development of the computer program BUNVIS (Buckling or Natural Vibration of Space Frames) and BUNVIS-RG (Buckling or Natural Vibration of Space Frames with Repetitive Geometry) which received widespread attention. Numerous research papers emerged using BUNVIS and BUNVIS-RG as research tools. The author’s main contributions in the Aeronautical Engineering field are, however, related to the solutions of problems in aeroelasticity, initially for metallic aircraft and in later years for composite aircraft. He investigated the aeroelastic problems of tailless aircraft for the first time in his doctoral studies about 40 years ago. In this research, a unified method combining two major disciplines of aircraft design, namely that of stability and control, and that of flutter and response, was developed to study the interaction between the rigid body motions of an aircraft and its elastic modes of distortion. The computer program CALFUN (CALculation of Flutter speed Using Normal modes) was developed by the author for metallic aircraft and later extended to cover composite aircraft. The associated theories for composite aircraft were developed and the allied problems of dynamic response to both deterministic and random loads were solved. With the advent of advanced composite materials, the author’s research turned to aeroelasticity of composite aircraft and then to optimization studies. New, novel and accurate methods were developed and significant inroads were made. The author broke new ground by applying symbolic computation as an aid to the solution of his research problems. The computational efficiency of this new approach became evident as a by-product of his research. The development of software based on his theories has paved the way for industrial applications. His research works on dynamic stiffness modelling of composite structures using layer-wise and higher order shear deformation theory are significant developments in composites engineering. Such pioneering developments were necessitated by the fact that existing methodologies using classical lamination theory are not sufficiently accurate, particularly when the structural components made from composite materials are thick, e.g. the fuselage of a transport airliner. Given the close relationship between structural engineering and material science, the author’s research has broadened into polymers and nano-composites, functionally graded materials and hot ductility of steel. His research activities are continuing and expanding with further diversification of his interests.
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Ambrozic, Courtney Lynn. "Image Deblurring for Material Science Applications in Optical Microscopy." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1532625732841875.
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Maguire, John F. "Contributions to materials science and engineering." Thesis, Ulster University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515891.
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Gupta, Gaurav. "Computational material science of carboncarbon : composites based on carbonaceous mesophase matrices." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=83865.
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Carbon/Carbon composites belong to the generic class of fiber reinforced composites and are widely used because of their high strength as well as chemical and thermal stability. Like other fiber reinforced composites they consist of the fibers which act as reinforcements and matrix which acts as a glue that binds the fibers. c/c composites from pitch based precursor are unique since the matrix in this case is a liquid crystal or mesophase. This makes them remarkable in the sense that unlike c/c composites from other precursors such as PAN, rayon etc. they have extremely high degree of molecular orientation and exhibit texture. An important characteristic of their textures is the presence of topological defects. It is hence of great interest to understand and elucidate the principles that govern the formation of textures so as to optimize their properties. In this work we present a computational study of structure formation in carbon-carbon composites that describes the emergence of topological defects due to the distortions in the oriented matrix created by the presence of fiber matrix interaction. Dynamical and structural features of texture formation were characterized using gradient elasticity and defect physics.
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Tai, Yen-Ju Timothy. "Towards material-informed tectonics." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120393.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>This thesis introduces, demonstrates, and implements a unified computational design framework for material distribution modeling that enables the production of geometrically complex, materially heterogeneous, and functionally graded objects, across scales, media, and platforms. Receiving user-defined performance mappings as input, the workflow generates and evaluates instructions for designated fabrication systems, informed by the extrinsic constraints presented by the hardware and the intrinsic characteristics embedded in the materials utilized. As a proof of concept to the generalizable approach, three novel design-to-fabrication processes within the framework are introduced with material and materialization precedents and implemented through computational and robotic platforms: implicit modeling for the fabrication of photopolymers, trajectory optimizing for the fabrication of water-based material, and toolpath planning for the fabrication of fiber-based material. Titled Material-informed Tectonics, the framework extends the domain of parametric design processes from geometry to material, expands the potential application of volumetric material modeling techniques beyond high resolution multi-material 3D printing systems, and bridges between the virtual and the physical by integrating material information into the tectonic relationship between manufactured objects and manufacturing methods; thereby outlining an approach towards a synthesis of material properties, computational design, digital fabrication, and the environment.<br>by Yen-Ju Timothy Tai.<br>S.M.
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Kang, Byoungwoo. "Designing materials for energy storage with high power and energy density : LiFePO₄ cathode material." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/59707.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, February 2010.<br>"February 2010." Cataloged from PDF version of thesis.<br>Includes bibliographical references.<br>LiFePO₄ has drawn a lot of attention as a cathode material in lithium rechargeable batteries because its structural and thermal stability, its inexpensive cost, and environmental friendliness meet the requirements of power sources for electric vehicles, except high power capability. Strategies to increase the rather sluggish rate performance of bulk LiFePO₄ have focused on improving electron transport in the bulk or at the surface of the material, or on reducing the path length over which the electron and Li* have to move by using nano-sized materials. However, recent evidence indicates LiFePO₄ is pure one dimensional lithium conductor. So, lithium transport is as important as electron transport. Strong anisotropic lithium diffusion results in limited transports of lithium ions in both the bulk and the surface. Reducing the particle size improves the transport of lithium ions in the bulk, and modification of the surface with a lithium-ion conducting material should enhance the transport of lithium ions on the surface. A poorly crystallized lithium phosphate phase on the surface of nanoscale LiFePO₄ is created by using proper off-stoichiometry (LiFeo.9Po.9504.3). The off-stoichiometric strategy leads to small particles less than 50 nm through grain growth restriction and a poorly crystallized lithium phosphate on the surface. The conducting surface phase can not only improve the transport of lithium ions on the surface but also facilitate the access of lithium ions to the surface by reducing anisotropic lithium diffusion on the surface induced by its amorphous nature. The off-stoichiometric material shows extremely high rate performance, achieving reasonable capacity even at 400C (9 s charge/discharge). In this thesis, the main finding is as follows: LiFePO₄ shows fast bulk kinetics and in itself does not limit the rate of charge and discharge. When bulk Li transport is very fast, the battery charging and discharging are limited by other factors such as the surface adsorption and surface transfer of lithium ions and the configuration of a cell. The off-stoichiometric strategy to improve surface transports addresses the right rate-limiting step and reveals the real capability of LiFePO₄.<br>by Byoungwoo Kang.<br>Ph.D.
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Wehage, Kristopher. "Tools for Material Design and Selection." Thesis, University of California, Davis, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1569815.
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<p> The present thesis focuses on applications of numerical methods to create tools for material characterization, design and selection. The tools generated in this work incorporate a variety of programming concepts, from digital image analysis, geometry, optimization, and parallel programming to data-mining, databases and web design. </p><p> The first portion of the thesis focuses on methods for characterizing clustering in bimodal 5083 Aluminum alloys created by cryomilling and powder metallurgy. The bimodal samples analyzed in the present work contain a mixture of a coarse grain phase, with a grain size on the order of several microns, and an ultra-fine grain phase, with a grain size on the order of 200 nm. The mixing of the two phases is not homogeneous and clustering is observed. To investigate clustering in these bimodal materials, various microstructures were created experimentally by conventional cryomilling, Hot Isostatic Pressing (HIP), Extrusion, Dual-Mode Dynamic Forging (DMDF) and a new 'Gradient' cryomilling process. Two techniques for quantitative clustering analysis are presented, formulated and implemented. The first technique, the Area Disorder function, provides a metric of the quality of coarse grain dispersion in an ultra-fine grain matrix and the second technique, the Two-Point Correlation function, provides a metric of long and short range spatial arrangements of the two phases, as well as an indication of the mean feature size in any direction. The two techniques are implemented on digital images created by Scanning Electron Microscopy (SEM) and Electron Backscatter Detection (EBSD) of the microstructures. </p><p> To investigate structure–property relationships through modeling and simulation, strategies for generating synthetic microstructures are discussed and a computer program that generates randomized microstructures with desired configurations of clustering described by the Area Disorder Function is formulated and presented. In the computer program, two-dimensional microstructures are generated by Random Sequential Adsorption (RSA) of voxelized ellipses representing the coarse grain phase. A simulated annealing algorithm is used to geometrically optimize the placement of the ellipses in the model to achieve varying user-defined configurations of spatial arrangement of the coarse grains. During the simulated annealing process, the ellipses are allowed to overlap up to a specified threshold, allowing triple junctions to form in the model. Once the simulated annealing process is complete, the remaining space is populated by smaller ellipses representing the ultra-fine grain phase. Uniform random orientations are assigned to the grains. The program generates text files that can be imported in to Crystal Plasticity Finite Element Analysis Software for stress analysis. </p><p> Finally, numerical methods and programming are applied to current issues in green engineering and hazard assessment. To understand hazards associated with materials and select safer alternatives, engineers and designers need access to up-to-date hazard information. However, hazard information comes from many disparate sources and aggregating, interpreting and taking action on the wealth of data is not trivial. In light of these challenges, a Framework for Automated Hazard Assessment based on the GreenScreen list translator is presented. The framework consists of a computer program that automatically extracts data from the GHS-Japan hazard database, loads the data into a machine-readable JSON format, transforms the JSON document in to a GreenScreen JSON document using the GreenScreen List Translator v1.2 and performs GreenScreen Benchmark scoring on the material. The GreenScreen JSON documents are then uploaded to a document storage system to allow human operators to search for, modify or add additional hazard information via a web interface.</p>
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Shi, Chao. "Finite Block Method and applications in engineering with Functional Graded Materials." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/39764.
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Fracture mechanics plays an important role in understanding the performance of all types of materials including Functionally Graded Materials (FGMs). Recently, FGMs have attracted the attention of various scholars and engineers around the world since its specific material properties can smoothly vary along the geometries. In this thesis, the Finite Block Method (FBM), based on a 1D differential matrix derived from the Lagrangian Interpolation Method, has been presented for the evaluation of the mechanical properties of FGMs on both static and dynamic analysis. Additionally, the coefficient differential matrix can be determined by a normalized local domain, such as a square for 2D, a cubic for 3D. By introducing the mapping technique, a complex real domain can be divided into several blocks, and each block is possible to transform from Cartesian coordinate (xyz) to normalized coordinate (ξησ) with 8 seeds for two dimensions and 20 seeds for three dimensions. With the aid of coefficient differential matrix, the differential equation is possible to convert to a series of algebraic functions. The accuracy and convergence have been approved by comparison with other numerical methods or analytical results. Besides, the stress intensity factor and T-stresses are introduced to assess the fracture characteristics of FGMs. The Crack Opening displacement is applied for the calculation of the stress intensity factor with the FBM. In addition, a singular core is adopted to combine with the blocks for the simulation of T stresses. Numerical examples are introduced to verify the accuracy of the FBM, by comparing with Finite Element Methods or analytical results. Finally, the FBM is applied for wave propagation problems in two- and three-dimensional porous mediums considering their poroelasticities. To demonstrate the accuracy of the present method, a one-dimensional analytical solution has been derived for comparison.
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Carroll, Patrick Eamonn. "Engineering Ireland : the material constitution of the technoscientific state /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9935447.
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Lisowski, Eva. "Evaluation of material attractiveness to non-state actors of various nuclear materials in Thorium fuel cycles." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127306.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, May, 2020<br>Cataloged from the official PDF of thesis.<br>Includes bibliographical references (pages 42-43).<br>Thorium-based fuel cycles for advanced nuclear reactors have been explored to utilize thorium resources in nations where uranium is scarce, increase fissile material utilization, and enhance proliferation resistance. As a stepping stone, thorium-based fuels have been paired with pressure tube heavy water reactors because of their high neutron economy and online refueling capability. However, thorium fuel cycles have raised proliferation concerns regarding the presence of U-233 following the irradiation of fuel bundles. The presence of Pa-233, which decays into pure U-233, and the creation of Pu-239 due to the neutron capture of U-238 in mixed lightly-enriched uranium (LEU)/Thorium fuels, are also causes for proliferation concern.<br>Based on a method developed in a previous study, the material attractiveness to non-state actors of fissile materials present in a 40%LEU/60%Th fuel lattice concept was evaluated for six metrics: bare critical mass (BCM), heat content, net weight, acquisition time, dose rate, and processing time & complexity. The lattice, composed of 35 fuel pins and a central ZrO2 displacer rod, was modeled and depleted in the OpenMC reactor physics software, over a range of burnups up to 40 MWd/kg followed by two years of cooling. It was found that the material attractiveness of uranium isotopes in the irradiated fuel bundle was Very Low due to the high fraction of U-238 present in the fuel and the assumed lack of enrichment capabilities among non-state actors. However, for a state with basic enrichment capabilities, this fuel may be attractive. The attractiveness of plutonium isotopes was also found, as expected in a thorium-cycle, to be Very Low.<br>However, the low BCM and heat content of this mixture reveals that it could be attractive to states that can easily acquire the material and do not need to rely on the theft of many fuel bundles to acquire an IAEA Category I quantity of material. Further investigation of the material attractiveness to states is required. Material attractiveness evaluations are important to informing future decisions regarding which fuel bundles to select when designing advanced reactor facilities and developing methods to safeguard them.<br>by Eva Lisowski.<br>S.B.<br>S.B. Massachusetts Institute of Technology, Department of Nuclear Science and Engineering
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Monreal, Jorge. "Thermoelectrics : material advancements and market applications." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42156.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.<br>Includes bibliographical references (leaves 77-78).<br>Thermoelectric properties have been known since the initial discovery in 1821 by Thomas Seebeck, who found that a current flowed at the junction of two dissimilar metals when placed under a temperature differential. This was followed by the discovery in 1834 by John Peltier, that the inverse was also true. That is, that a current applied to two dissimilar metals would yield a temperature differential. Interest in thermoelectrics laid dormant for almost 100 years and were primarily a laboratory curiosity. That interest was revived in the early 1900s with applications for remote power generation aboard satellites and several military applications. Thermoelectric devices, such as beverage coolers or thermocouples for temperature sensors, that tried to make use of these characteristics shortly followed. However, commercial success soon slowed down as efficiencies of the materials were not conducive to profitability. The effectiveness of a thermoelectric was described by a dimensionless figure of merit given by ZT=(S2a/ke+kp)T, where S is the Seebeck coefficient, T is the operational temperature, a is the electrical conductivity, ke is the electron contribution to thermal conductivity, and kp is the thermal conductivity due to phonon propagation across a crystal lattice. From the mid-1940s until the 1970s there was very slow progress in increased thermoelectric material efficiency, which culminated in a ZT=1 with (Bi2Te3). For approximately 30 years progress stagnated. In 1993, however, new ideas emerged that called for the fabrication of low dimensional structures to enhance electron conductivity while inhibiting phonon contribution to thermal conductivity. Advancements in material efficiency have made great progress since then.<br>(cont.) Businesses are, once again, looking at thermoelectrics for potential commercial ventures. This thesis will begin with an examination of the theory behind thermoelectric properties, followed by an explanation of the methods used to assess thermoelectric device and material performance. It will then review some of the advancements made in low dimensional structures such as two-dimensional structures of quantum wells, one-dimensional nanowires, and zero-dimensional quantum dots. A market analysis of current commercial applications is presented. A proposed business model exploiting the power generation mode of thermoelectric devices is introduced. And, finally, an overview of the intellectual property landscape describes several patents relevant to the proposed business model.<br>by Jorge Monreal.<br>M.Eng.
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Kangude, Yamini. "Red emitting photonic devices using InGaP/InGaAlP material system." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33395.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.<br>Includes bibliographical references (leaves 57-58).<br>In this thesis, two red emitting photonic devices are presented using the InGaP/InGaAlP material system. InGaP/InGaAlP material system provides large flexibility in the band gap energy while being lattice matched to GaAs substrate. The devices consist of a quantum well active region and a distributed bragg reflector at the bottom to reduce loss of emitted light into the substrate. The first device emits at a wavelength of 650 nm and is intended to create a photonic crystal light emitting diode (PCLED). PCLEDs have been demonstrated to have higher efficiency compared to devices without the photonic crystal. The second device emits at 690 nm and is intended for integrating with an organic semiconductor to form a hybrid organic-inorganic emitter. The devices were grown using gas source molecular beam epitaxy (GSMBE) and then processed to form the final device. .<br>by Yamini Kangude.<br>S.M.
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Cyr, Pierre. "Development of a computer application for optimization of composite material structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0030/MQ64214.pdf.
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Shazly, Tarek (Tarek Michael). "Tissue-material interactions : bioadhesion and tissue response." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54577.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 159-162).<br>Diverse interactions between soft tissues and implanted biomaterials directly influence the success or failure of therapeutic interventions. The nature and extent of these interactions strongly depend on both the tissue and material in question and can presumably be characterized for any given clinical application. Nevertheless, optimizing biomaterial performance remains a challenge in many implant scenarios due to complex relationships between intrinsic material properties and tissue response. Soft tissue sealants are clinically-relevant biomaterials which impart therapeutic benefit through adhesion to tissue, thus exhibiting a direct functional dependence on tissue-material reactivity. Because adhesion can be rigorously quantified and correlated to the local tissue response, sealants provide an informative platform for studying material properties, soft tissues, and their interplay. We developed a model hydrogel sealant composed of aminated polyethylene glycol and dextran aldehyde (PEG:dextran) that can possess a wide range of bulk and adhesive properties by virtue of constituent polymer modifications. Through comparison to traditional sealants, we established that highly viscoelastic adhesion promotes tissue-sealant interfacial failure resistance without compromising underlying tissue morphology.<br>(cont.) We analyzed multiple soft tissues to substantiate the notion that natural biochemical variability facilitates the design of tissue-specific sealants which have distinct advantages over more general alternatives. We confirmed that hydrogel-based materials are an attractive material class for ensuring sealant biocompatibility, but found that a marked reduction in adhesive strength following characteristic swell can potentially limit clinical efficacy. To mitigate the swell-induced loss of hydrogel-based sealant functionality, a biomimetic conjugation strategy derived from marine mussel adhesion was applied to PEG:dextran and shown to favorably modulate adhesion. In all phases of this research, we defined material design principles that extend beyond the immediate development of PEG:dextran with potential to enhance the clinical performance of a range of biomaterials.<br>by Tarek Shazly.<br>Ph.D.
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Chiang, Diana C. (Diana Chih-Chan) 1975. "Underfill material selection for flip chip technology." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50454.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.<br>Includes bibliographical references (leaf 34).<br>Six underfill materials were examined for the selection of an appropriate underfill material for Digital Equipment Corporation's flip chip development project. Several tests were performed to determine the material properties, process properties, and the reliability of each underfill material. A material with a fast flow rate, uniform and void free flow pattern, fast curing schedule, good thermal and mechanical properties, and good reliability results is needed to satisfy the requirements for this project. Materials F and E exhibited all the above requirements and were concluded as the two best underfill materials for the flip chip process. Important material properties which contributed to the desired results of these materials include a filler particle content of about 65%, a weight loss percentage during cure of less than 1%, and a Tg of 140°C.<br>by Diana C. Chiang.<br>S.M.
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Ngan, Wai Kit Addy 1979. "Acquisition and modeling of material appearance." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38307.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.<br>Includes bibliographical references (p. 131-143).<br>In computer graphics, the realistic rendering of synthetic scenes requires a precise description of surface geometry, lighting, and material appearance. While 3D geometry scanning and modeling have advanced significantly in recent years, measurement and modeling of accurate material appearance have remained critical challenges. Analytical models are the main tools to describe material appearance in most current applications. They provide compact and smooth approximations to real materials but lack the expressiveness to represent complex materials. Data-driven approaches based on exhaustive measurements are fully general but the measurement process is difficult and the storage requirement is very high. In this thesis, we propose the use of hybrid representations that are more compact and easier to acquire than exhaustive measurement, while preserving much generality of a data-driven approach. To represent complex bidirectional reflectance distribution functions (BRDFs), we present a new method to estimate a general microfacet distribution from measured data. We show that this representation is able to reproduce complex materials that are impossible to model with purely analytical models.<br>(cont.) We also propose a new method that significantly reduces measurement cost and time of the bidirectional texture function (BTF) through a statistical characterization of texture appearance. Our reconstruction method combines naturally aligned images and alignment-insensitive statistics to produce visually plausible results. We demonstrate our acquisition system which is able to capture intricate materials like fabrics in less than ten minutes with commodity equipments. In addition, we present a method to facilitate effective user design in the space of material appearance. We introduce a metric in the space of reflectance which corresponds roughly to perceptual measures. The main idea of our approach is to evaluate reflectance differences in terms of their induced rendered images, instead of the reflectance function itself defined in the angular domains. With rendered images, we show that even a simple computational metric can provide good perceptual spacing and enable intuitive navigation of the reflectance space.<br>by Wai Kit Addy Ngan.<br>Ph.D.
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Wong, Jennifer L. "A material segmentation and classification system." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85523.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (page 75).<br>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. The material classification of each region is then based on the cosine lobe model. The cosine lobe model is our adopted reflectance model, which allows for a simple approximation of a material's reflectance properties, which then serves as the material's unique signature.<br>by Jennifer L. Wong.<br>M. Eng.
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Goyal, Amit 1979. "Synchronized exchange of material and information." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/17605.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, June 2003.<br>Includes bibliographical references (leaves 39-41).<br>Commerce is all about the carefully managed exchange of material, money, and information. Traditionally, the connection between material and information has been tenuous, with humans acting as the intermediaries. This has made the supply chain inefficient and expensive. The Auto-lID Center has created a stronger, automatic link between inanimate objects and computers. This thesis completes the information exchange, or feedback loop, which makes commerce possible. Specifically, it identifies a framework for information exchange alongside material exchange using Savant-to-Savant communication. Messaging standards will need to support the Auto-ID Center's technology, and this thesis suggests how to augment existing and emerging communication standards to accomplish this feat. Finally, to address the issue of increasing information management, this thesis analyzes the aggregation database, an IT infrastructure component that might be of value to organizations. The outcome of this thesis is an understanding of the various issues necessary to develop a secure, efficient and robust system for tracking and automatically confirming material exchange.<br>by Amit Goyal.<br>M.Eng.
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Hilton, Nathan Rhead. "Material uniformity of cadmium zinc telluride in gamma-ray imaging detectors." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280187.
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The material uniformity of cadmium zinc telluride (CZT) crystals in gamma-ray imaging detectors is examined using several existing techniques and a new technique called thermally stimulated current (TSC) imaging that has been developed for this dissertation. The TSC imaging model, simulations, and experimental demonstrations are presented here for the first time. CZT radiation detectors are used in nuclear medicine as well as other medical, industrial, national security, and scientific applications; however, the scarcity and cost of high-quality CZT materials have hindered the use of CZT in these applications. Understanding CZT's material properties and their effects on detector performance should be helpful in developing crystal growth methods that have improved yield of useful detector material. Data obtained from CZT samples using infrared transmission, electron microprobe, X-ray diffraction, and electron backscatter diffraction (EBSD) mapping methods are used to understand their crystal structure. Data obtained from these samples using both TSC imaging and conventional leakage current measurements while these samples were operated as pixelated detector arrays are used to understand their charge transport properties. Collimated gamma-ray mapping was used to understand the detector performance properties of these samples. Correlations among these spatially mapped data are investigated. Contrary to the suggestions of other researchers, it is found that leakage current is not inversely correlated with detector performance. Detector performance in these samples is well correlated with their crystal structure. High-angle grain boundaries are shown to trap charge carriers, and estimates of the locations of these boundaries are derived from the gamma-ray mapping data. EBSD distinguishes itself from X-ray diffraction methods in identifying the locations and types of grain boundaries intersecting the sample surface. Using the new TSC imaging method, evidence is obtained showing a higher density of a particular trap near incommensurate boundaries in a CZT sample. Other researchers have indicated that an electron trap associated with dislocations is present in CZT. Their observation is consistent with a conclusion drawn from these TSC imaging data that due to higher densities of dislocations near incommensurate grain boundaries these boundaries host electron traps while {111} twin boundaries do not.
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Haidemenopoulos, Gregory N. "Heat flow and material degradation during laser metal forming." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/14898.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering and Dept. of Materials Science and Engineering, 1985.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING<br>Bibliography: leaves 144-146.<br>by Gregory N. Haidemenopoulos.<br>M.S.
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Ren, Yong-Gang Frank. "Erbium doped silicon as an optoelectronic semiconductor material." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36468.
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Volpicelli, Alicia M. (Alicia Marina) 1976. "Automation of electrostatic material property measurement procedures." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86567.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.<br>Includes bibliographical references (leaves 34-35).<br>by Alicia M. Volpicelli.<br>S.B.and M.Eng.
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Vidimče, Kiril. "A programmable pipeline for multi-material fabrication." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89863.
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Thesis: S.M. in Computer Science and Engineering, Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>42<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 46-51).<br>3D printing hardware is rapidly scaling up to output continuous mixtures of multiple materials at increasing resolution over ever larger print volumes. This poses an enormous computational challenge: large high-resolution prints comprise trillions of voxels and petabytes of data and simply modeling and describing the input with spatially-varying material mixtures at this scale is challenging. Existing 3D printing software is insufficient; in particular, most software is designed to support only a few million primitives, with discrete material choices per object. In this body of work I present OpenFab, a programmable pipeline for synthesizing multi-material 3D printed objects that is inspired by RenderMan and modern GPU pipelines. The pipeline supports procedural evaluation of geometric detail and material composition by using shader-like fablets. The pipeline allows models to be specified easily and efficiently. Additionally, I describe a streaming architecture for implementing OpenFab; only a small fraction of the final volume is stored in memory and output is fed to the printer with little startup delay. I demonstrate the OpenFab pipeline and programming model on a variety of multi-material objects.<br>by Kiril Vidimče.<br>S.M. in Computer Science and Engineering
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Zhou, You. "Correlated Oxides: Material Physics and Devices." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17464472.
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In this work we study the metal-insulator transition in vanadium dioxide and samarium nickelate and the application of such transitions in electronic devices. Chapter 1 provides an introduction to the Mott metal-insulator transition mechanisms and an overview of the interplay between various degrees of freedom in correlated oxides. The phase transition in vanadium dioxide is presented as an example to emphasize the overarching electron-phonon and electron-electron interaction driven transition mechanisms. In Chapter 2, we describe the growth and structure-functionality relationship of thin film transition metal oxides. Chapter 3 goes on to examine the mechanism of voltage-triggered metal-insulator transition in vanadium dioxide two-terminal threshold switches through dynamic studies. Chapter 4 delves into the mechanism of conductance modulation in electrolyte-gated vanadium dioxide transistors, which reveals the importance of electrochemical effects versus electrostatic effects in these devices. Utilizing the idea of electrochemical doping, we designed and realized a strongly correlated insulating phase in samarium nickel oxide through electron doping with hydrogen and lithium interstitials in Chapter 5. Such techniques can be extended to other materials to achieve reversible and controllable carrier doping with high concentration to study the related physics.<br>Engineering and Applied Sciences - Applied Physics
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Li, Preston Pui-Chuen. "Strategies for aluminum recycling : insights from material system optimization." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33611.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.<br>Includes bibliographical references (p. 181-185).<br>The dramatic increase in aluminum consumption over the past decades necessitates a societal effort to recycle and reuse these materials to promote true sustainability and energy savings in aluminum production. However, the path towards this goal is full of challenges which lead to inefficiencies in the usage of secondary materials. These frictions are due to (i) rapidly changing consumption patterns, (ii) compositional incompatibility in scrap streams and (iii) incomplete information in the decision making process around scrap consumption. This thesis tackles these inefficiencies by developing optimization-based decision tools and modeling techniques for the assessment of sorting technologies and scrap management from procurement to production. In the course of managing and accounting for the aforementioned variability and uncertainties in the material system inputs, the goal is to present cost-effective strategies to increase scrap consumption under applicable context of different operating environment in aluminum production. These decision tools also aim to foster a fundamental shift in decision-making behavior to factor in uncertainties into the scrap management process.<br>(cont.) A sorting algorithm with an arbitrary number of output streams is created as a guide to quantify the effects of wrought and cast recovery rates, sorting cost, scrap content, and product mix on sorting technologies application and development. In collaboration with Norsk Hydro Aluminum, an evaluation of wrought-versus-cast sorting technology is undertaken. For a reasonable range of sorter recovery rates and costs, the process leads to overall cost savings and increase in scrap consumption. Unlike cost savings and scrap consumption, however, the sorter utilization rate does not increase monotonically with improvements in recovery rates. Furthermore, under limited scrap supplies, not all products benefited in increased scrap consumption with sorting. Stochastic optimization techniques are introduced to address demand and scrap compositions uncertainties faced by different decision-makers along the aluminum production chain. With the idea of recourse and scrap net residual value, increased scrap purchase and usage were determined to be an effective hedge against adverse demand swings. Traditional forecast-based deterministic decision tools were found to be too costly and conservative in scrap usage on average.<br>(cont.) At the operator level, stochastic modeling draws relevance in its ability to link production tolerance level for compositional variance to the underlying compositional uncertainties in scrap materials. The technique also supports diversification in scrap sources as a way to mitigate compositional variance in product scrap usage. Overall these models and methodologies target various scrap usage inefficiencies in the aluminum production chain. Their application and associated insights can bring society one step closer towards sustainable development, not only in aluminum, but potentially for other light metals as well.<br>by Preston Pui-Chuen Li.<br>Ph.D.
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Ahn, Sang Hoon 1970. "Electrical studies of silicon and low K dielectric material." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9130.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1999.<br>Includes bibliographical references (leaves 108-111).<br>Junction capacitance measurement is a well-established powerful characterization technique that allows one to explore electrical and physical properties of defects in bulk and interface of electronic materials. Capacitance-Voltage (CV) measures the overall net carrier concentration and a built-in voltage for a diode junction. Deep level transient spectroscopy (DLTS) as one of the most sensitive electrical measurement techniques can detect electrically active impurity concentration on the level of 10-1 to 10-5 of substrate doping concentration. The characteristic energy level and capture cross-section of the traps in the semiconductor energy gap can be extracted from DLTS temperature scans. Coupled with CV free carrier concentration profile, isothermal profiling by DLTS can determine the distribution of electrically active defects in the semiconductor. CV can also measure dielectric constant, K, on a metal-oxide-silicon structure. In this thesis, the junction capacitance technique is a primary tool used to study Er, Fe, and Mo in silicon. Si:5r is a candidate system for a light emitter in Si-based microphotonics. Fe is one of the most troublesome elements that degrade integrated circuit performance and solar cell efficiency. Mo is a fairly unknown contaminant typical of integrated circuit processing. Fluorosilicate glass is being used as a dielectric material for inter-metal levels in the current generation microprocessor. By measuring the reaction kinetics of the Er-related donor state, a defect structure for Si:Er light emitter center was deduced. The role of heterogeneous precipitation in Fe internal gettering was observed and modeled by measurement of residual [FeB] associates following [Fe] saturation, quench, and annealing processing. The diffusivity of Mo was determined and models for both the substitutional and the kick out diffusion mechanism were constructed. Finally, a predictive model for the F-content dependent dielectric constant variation of Si02 was established.<br>by Sang Hoon Ahn.<br>Ph.D.
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Padilla, Eduardo A. "Characterization of fissile material using low energy neutron interrogation." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41299.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.<br>Includes bibliographical references (p. 76).<br>The glaring need to develop methods for detecting and interdicting illicit nuclear trafficking has resulted in the exploration of various methods for active neutron interrogation, specifically for the presence of special nuclear material (SNM) in cargo containers. The proposed system aims to defeat the ability of terrorists to import SNM into the United States via maritime shipping, thus greatly reducing the possibility of a successful nuclear terrorist attack. The proposed system uses 60-100 keV neutrons, produced by the 7Li(p,n)7Be reaction in a linear accelerator and kinematically beamed into various targets. In the event that fissile material is present, highly energetic neutrons will be emitted from the fissioning of a nucleus and some of these neutrons will eventually radiate from the container. Inevitably, high energy photons will also radiate from the target due to the interactions of neutrons and host materials. Utilizing a neutron detection system that is able to discriminate low energy neutrons, high energy gamma rays and the high energy neutrons from fission enables the detection of fissile material in various containers. An increase in discriminated high energy neutron events during active neutron interrogation selectively indicates the presence of SNM, since neutron energies on the order of 1 MeV are required for the SNM-equivalent fissioning potential when incident upon U238 and other high-Z nuclei. Furthermore, neutrons with less than approximately 100 keV do not undergo nuclear processes such as (n,2n) and (n,n'), but rather lose their energy through kinematic collisions.<br>(cont.)Results obtained validate this proof-of-concept, in that observed high energy neutron events increase significantly in the presence of gram-quantities of SNM. Further, attempts made to shield the SNM from active interrogation do not defeat the proposed system's ability to identify the presence of SNM. With a fully-functional proof-of-concept, further work towards developing a complete and deployable prototype active neutron interrogation system will serve to augment the ability of the United States to detect, deter and interdict illicit nuclear trafficking.<br>by Eduardo A. Padilla.<br>S.M.
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Hartwig, Zachary Seth. "An in-situ accelerator-based diagnostic for plasma-material interactions science in magnetic fusion devices." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87488.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 149-162).<br>Plasma-material interactions (PMI) in magnetic fusion devices such as fuel retention, material erosion and redeposition, and material mixing present significant scientific and engineering challenges, particularly for the next generation of devices that will move towards reactor-relevant conditions. Achieving an integrated understanding of PMI, however, is severely hindered by a dearth of in-situ diagnosis of the plasma-facing component (PFC) surfaces. To address this critical need, this thesis presents an accelerator-based diagnostic that nondestructively measures the evolution of PFC surfaces in-situ. The diagnostic aims to remotely generate isotopic concentration maps that cover a large fraction of the PFC surfaces on a plasma shot-to-shot timescale. The diagnostic uses a compact, high-current radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak. The tokamak magnetic fields in between plasma shots are used to steer the deuterons to PFCs where the deuterons cause high-Q nuclear reactions with low-Z isotopes ~5 [mu]m into the material. Scintillation detectors measure the induced neutrons and gammas; energy spectra analysis provides quantitative reconstruction of surface concentrations. An overview of the diagnostic technique, known as accelerator-based in-situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod is given; a description of the complementary simulation tools is also provided. Experimental validation is shown to demonstrate the optimized beam injection into the tokamak, the quantification of PFC surfaces isotopes, and the measurement localization provided by magnetic beam steering. Finally, the first AIMS measurements of fusion fuel retention are presented, demonstrating the local erosion and codeposition of deuterium-saturated boron surface films. The finding confirms that deuterium codeposition with boron is insufficient to account for the net fuel retention in Alcator C-Mod.<br>by Zachary Seth Hartwig.<br>Ph. D.
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Lagerstedt, Anders. "On the shrinkage of metals and its effect in solidification processing." Doctoral thesis, KTH, Materials Science and Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-75.
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<p>The shrinkage during solidification of aluminium and iron based alloys has been studied experimentally and theoretically. The determined shrinkage behaviour has been used in theoretical evaluation of shrinkage related phenomena during solidification. </p><p>Air gap formation was experimentally studied in cylindrical moulds. Aluminium based alloys were cast in a cast iron mould while iron based alloys were cast in a water-cooled copper mould. Displacements and temperatures were measured throughout the solidification process. The modelling work shows that the effect of vacancy incorporation during the solidification has to be taken into account in order to accurately describe the shrinkage. </p><p>Crack formation was studied during continuous casting of steel. A model for prediction of crack locations has been developed and extended to consider non-equilibrium solidification. The model demonstrates that the shrinkage due to vacancy condensation is an important parameter to regard when predicting crack formation. </p><p>The centreline segregation was studied, where the contributions from thermal and solidification shrinkage were analysed theoretically and compared with experimental findings. In order to compare macrosegregation in continuous casting and ingot casting, ingots cast with the same steel grade was analysed. However, the macrosegregation due to A-segregation is driven by the density difference due to segregation. This is also analysed experimentally as well as theoretically.</p>
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Krones, Jonathan Seth. "Reverse logistics and large-scale material recovery from electronics waste." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42994.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.<br>Includes bibliographical references (p. 107-111).<br>Waste consolidation is a crucial step in the development of cost-effective, nation-wide material reclamation networks. This thesis project investigates typical and conformational tendencies of a hypothetical end-of-life electronics recycling system based in the United States. Optimal waste processor configurations, along with cost drivers and sensitivities are identified using a simple reverse logistics linear programming model. The experimental procedure entails varying the model scenario based on: type of material being recycled, the properties of current recycling and consolidation practices, and an extrapolation of current trends into the future. The transition from a decentralized to a centralized recycling network is shown to be dependent on the balance between transportation costs and facility costs, with the latter being a much more important cost consideration than the former. Additionally, this project sets the stage for a great deal of future work to ensure the profitability of domestic e-waste recycling systems.<br>by Jonathan Seth Krones.<br>S.B.
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Erickson, Anna S. "Remote detection of fissile material : Cherenkov counters for gamma detection." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76496.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 161-167).<br>The need for large-size detectors for long-range active interrogation (Al) detection has generated interest in water-based detector technologies. AI is done using external radiation sources to induce fission and to detect, identify, and characterize special nuclear material (SNM) through the gamma rays and neutrons emitted. Long-range applications require detectors with a large solid angle and an ability to significantly suppress lowenergy background from linear electron accelerators. Water Cherenkov Detectors (WCD) were selected because of their transportability, scalability, and an inherent energy threshold. The main objective of this thesis was to design a large-size WCD capable of detecting gamma rays and to demonstrate particle energy discrimination ability. WCD was modeled in detail using Geant4 for optimization purposes. The experimental detector is composed of an aluminum body with a high efficiency (98.5%) diffuse reflector. Cherenkov photons are detected with six 8" hemispherical Hamamatsu photomultiplier tubes (PMT). PMTs are calibrated using two monoenergetic LEDs. The detector was shown to successfully detect gamma rays of energies above the Cherenkov threshold. The detector was able to discriminate between various sources, such as ⁶⁰Co and ²³²Th, even though WCD are known for their poor energy resolution. The detector design and analysis was completed, and it was demonstrated both computationally and experimentally that it is possible to use WCD to detect and characterize gamma rays. One of the accomplishments of this thesis was demonstration of event reconstruction capability of the detector system. A full-detector model was created using Geant4 simulation toolkit. The performance of the detector was predicted using the model and then experimentally verified. The qualitative agreement between the model and the experiment was observed. The event reconstruction was an important part of the detector performance analysis. Post-experimental data processing was done using ROOT.<br>by Anna S. Erickson.<br>Ph.D.
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Tang, Ming Ph D. Massachusetts Institute of Technology. "Thermodynamic and morphological transitions in crystalline and soft material interfaces." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44316.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.<br>Includes bibliographical references (p. 187-208).<br>Interfaces are defects present in all materials. Interface transitions are characterized by abrupt changes in interface structure, chemistry and/or morphology under suitable conditions. They exist in many material systems and often produce profound changes in material properties. Several interface transitions in crystalline and soft materials that have not been previously well understood were studied in this thesis. In the first part of this thesis, a diffuse-interface thermodynamic framework was developed for grain boundary structural and chemical transitions. A graphical construction method was developed to predict conditions for grain boundary transitions. A grain boundary premelting transition is predicted for systems of fixed stoichiometry. When extended to binary systems, the diffuse-interface model predicts the existence of a coupled grain boundary premelting/prewetting transition, which produces cooperative grain boundary disordering and segregation at sub-eutectic and sub-solidus temperatures. The analysis rationalizes the thermodynamic origin of intergranular glassy films (IGFs) widely observed in multi-component ceramics and alloys, for which thermodynamic stability has not been well explained in previous research. Predictions on the conditions for IGF's formation are consistent with experiments. As part of this work, a prototype of "grain boundary complexion diagrams" was constructed which delineates the stability domains of different grain boundary "complexions" on bulk phase diagrams. Morphological transitions of interfaces in soft materials such as surfactant self-assembled structures were investigated in the second part of this thesis. A phase-field model was developed for simulating morphological evolution of surfactant aggregates in solutions.<br>(cont.) The model captures both the self-assembling behavior of surfactants and the effect of interface-curvature elastic-energy on the morphologies of self-assembled structures. Simulations of single surfactant micelle growth in dilute solutions reveal several previously unknown morphological transitions, including a disk-to-cylinder micellar shape transition and a tip-splitting instability of cylindrical micelles. It is proposed that the observed morphological instabilities provide kinetic pathways to the formation of branch points between individual cylindrical micelles, whose presence has significant effects on the rheological properties of solutions. Surface wetting transitions often display simultaneous changes in interface structure and morphology. Despite the extremely broad technical applications of the Si/SiO2 structure The equilibrium wetting properties of silicon oxide on silicon are poorly understood, This is partly due to the extremely low equilibrium oxygen activity for SiO2/Si coexistence (e.g. 10-37 torr at 700°C), which cannot be reached by current ultra-high vacuum techniques. In the third part of this thesis, a solid-state buffer method was developed to access oxygen partial pressures near the Si/SiO2 equilibrium with systematic control. It was discovered from experiments that silicon oxide does not perfectly wet Si(001) surfaces near the equilibrium oxygen activity, with the wetting morphology being oxide islands coexisting with a thin oxide layer of ~0.4nm on top of Si.<br>by Ming Tang.<br>Ph.D.
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Holzwarth, Charles W. III (Charles Willett). "Material selection and nanofabrication techniques for electronic photonic integrated circuits." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53248.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 149-154).<br>Electronic-photonic integrated circuits have the potential to circumvent many of the performance bottlenecks of electronics. To achieve the full benefits of integrating photonics with electronics it is generally believed that wavelength-division multiplexing is needed; requiring an integrated optical device capable of multiplexing/demultiplexing operations. One such device is a bank of microring-resonator filters with precisely spaced resonant frequencies. In this work, a fabrication strategy based on scanning-electron-beam lithography (SEBL) is presented for precisely controlling the resonant frequency of microring-resonator filters. Using this strategy it is possible to achieve dimensional control, on the tens-of- picometer scale, as required for microring-resonator filter banks. To correct for resonant-frequency errors present after fabrication, two forms of postfabrication tuning, one dynamic and one static, are demonstrated. It is also shown that hydrogen silsesquioxane (HSQ) can be converted into a high-quality overcladding for photonic devices by optimizing the annealing process. Finally, a postfabrication technique of localized substrate removal is presented, enabling the integration of photonics with CMOS electronics. Second-order microring-resonator filter banks were fabricated using SiNx and Si as the high -index core materials. By controlling the electron-beam-exposure dose it is possible to change the average microring-waveguide width to a precision better than 75 pm, despite the 6 nm SEBL address grid. Using postfabrication tuning the remaining resonant-frequency errors can be reduced to less than 1 GHz.<br>(cont.) By annealing HSQ in a an 02 atmosphere using rapid thermal processing, it is possible to create thick overcladding layers that have essentially the same optical properties as SiO2 with the excellent gap-filling and planarization properties of HSQ. Using XeF2 to locally etch an underlying Si substrate, waveguides with a propagation loss of -10 dB/cm were fabricated out of polysilicon deposited on 50 nm of SiO2.<br>by Charles W. Holzwarth, Ill.<br>Ph.D.
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Guo, Qiang M. Eng Massachusetts Institute of Technology. "Evaluation on the thin-film phase change material-based technologies." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37684.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.<br>Includes bibliographical references (leaves 68-69).<br>Two potential applications of thin film phase-change materials are considered, non-volatile electronic memories and MEMS (Micro-Electro-Mechanical Systems) actuators. The markets for those two applications are fast growing and rapidly changing, so new materials technologies with superior performance are of great interest. Devices made with thin film phase change materials are shown to offer significant performance improvements for memory applications and new triggering mechanisms for MEMS actuation. IP (Intellectual Property) analyses for both markets indicate significant new IP space in each of them. Rough estimations for cost and revenue are provided.<br>by Qiang Guo.<br>M.Eng.
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Kim, Jae Hyun S. B. Massachusetts Institute of Technology. "Analysis of historical trends in material production and price volatility." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119064.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 42-44).<br>Volatilities generate uncertainties in the market that critically impact the decisions of producers, consumers, and speculators alike. Historical trends in volatility can be studied as a means of better understanding current volatilities and predicting future ones in the industry. This study used the coefficient of variation (CV) as a relative metric to compare the historical production and price volatilities of various materials - 12 metals, cement, and steel - from 1900 through 2015. The long-term (1900-2015) and short-term (1995-2015) volatilities of these materials were quantified, and decades corresponding to periods of warfare and/or economic recession were shown to exhibit highest volatility. To complement the breadth of this approach, aluminum and steel were used as case studies to determine which factors - amongst production, consumption, energy price, and raw material price - drive trends in U.S. material price volatility. Volatility comparison graphs of material price and the factor in question were generated, and the root mean square (RMS) error between the volatilities was taken as a measure of their correlation. Volatilities in both aluminum and steel price were shown to correlate strongest with volatilities in raw material (bauxite and iron ore) price, with volatilities in steel also correlating comparatively with production and consumption dynamics. Overall, this study demonstrated the effectiveness of CV as a quantitative metric to assess historical volatilities and identified key market forces driving these volatilities for the aluminum and steel industries.<br>by Jae Hyun Kim.<br>S.B.
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Kling, Joseph A. "Examining Critical Material Supply Chains Through a Bayesian Network Model." Thesis, The George Washington University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10928265.
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<p> The United States economic and national security sectors remain vulnerable to shortages of critical materials due to the risks posed by disruptions in globally-dispersed supply networks. Numerous methods over the past 10 years have been proposed to identify, assess, and evaluate risks in critical material supply chains. This praxis provides a method to quantify the impact of supply disruptions and inform the application of risk mitigation measures for a critical material supply chain from mineral deposits to final platform. It proposes a Bayesian network modeling method not yet applied to the problem in publicly available studies and fits with an assessment methodology proposed by the National Science and Technology Center (NSTC). Results from this study provide indicative answers to how supply disruptions propagate through a selected critical material supply network, which nodes are vulnerable to supply disruptions, and whether mitigating actions can reduce the impact of supply disruptions. The approach here demonstrates that a Bayesian network model can be one of the tools in a criticality assessment methodology.</p><p>
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Tan, Aik Jun. "Dynamic modulation of material properties by solid state proton gating." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122082.
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This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 195-215).<br>As functionalities become more abundant in solid state devices, one key capability which remains lacking is an effective means to dynamically tune material properties. In this thesis, we establish a pathway towards this capability by utilizing the simplest ion known to mankind: the proton. We demonstrate for the first time dynamic control of magnetic properties in an all-solid-state heterostructures using solid state proton gating in a metal/oxide heterostructure. We also demonstrate dynamic modulation of magnetic anisotropy at a metal-metal interface through hydrogen insertion in a heavy metal adjacent to a ferromagnet. Besides magnetic properties, solid state proton gating also enables dynamic modulation of optical properties in a thin film oxide. We observe fast gating of optical reflectivity by ~10% at timescale down to ~20ms in a metal/oxide/metal heterostructure. Finally, we also demonstrate a room temperature reversible solid oxide fuel cell based on hydrogen storage. The cell has a small form factor which is suitable for energy storage in solid state microelectronics application. Our work hence provides a platform for complete control of material properties through solid state proton gating.<br>by Aik Jun Tan.<br>Ph. D.<br>Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering
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Osterberg, Peter Maynard. "Electrostatically actuated microelectromechanical test structures for material property measurement." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11097.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.<br>Includes bibliographical references (leaves 140-143).<br>by Peter Maynard Osterberg.<br>Ph.D.
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Yüksel, Ayça. "The AlInP material system in heterojunction bipolar transistor technology." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37728.
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Sharan, Lavanya. "The perception of material qualities in real-world images." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54644.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 135-146).<br>One can easily tell if a sidewalk is slippery, if food is fresh, if a spoon is made of plastic or stainless steel, or if a suspicious looking mole warrants a trip to the doctor. This ability to visually identify and discriminate materials is known as material perception and little is known about it. We have measured human material judgments on a wide range of complex, real world materials. We have gathered several diverse image databases and made use of them to conduct psychophysical studies. We asked observers to classify surfaces and objects as being made of fabric, paper, plastic or other common material categories. In the first part of this thesis, we present experiments that establish that observers can make these judgments of material category reliably, quickly and in challenging conditions of rapid presentation. We find that categorization performance cannot be explained by simple, low-level cues like color or high spatial frequencies. In the second part of the thesis, we explore judgments beyond those of common material categories. Observers judged many dimensions of material appearance such as matte vs. glossy, opaque vs. translucent, rigid vs. nonrigid, soft vs. rough to touch, and even genuine vs. fake for familiar object categories like flowers, fruits and dessert. Observers were surprisingly accurate, even in 40 millisecond presentations. In the final part of this thesis, we compare the performance of state-of-art computer vision techniques with human performance on our images and tasks and find current techniques to be severely lacking.<br>(cont.) Taken together, our findings indicate that material perception is a distinct mechanism and can be as fast and flexible as object recognition or scene perception. When recognizing materials, low-level image information is of limited use for both humans and computer vision systems. We conclude that material recognition is a rich and challenging problem domain and there is much ground to be covered in both visual perception and computer vision.<br>by Lavanya Sharan.<br>Ph.D.
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Nisser, Martin(Martin Eric William). "3D printing dissolvable support material for time-dependent mechanisms." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122762.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 50-53).<br>In this thesis, a novel approach to the use of dissolvable material is proposed: rather than 3D printing support structures strictly for supporting overhangs, we explore use cases derived from its ability to be dissolved when placed in a solvent, such as water. This enables a range of new use cases, such as quickly dissolving and replacing parts of a prototype during design iteration, printing temporary assembly labels directly onto objects that leave no visual artifacts once dissolved, and creating time-dependent mechanisms, such as fading in parts of an image in a shadow art piece or releasing scents from a 3D printed structure sequentially overnight. We use commercially available support material, rendering the approach usable on consumer 3D printers without any further modifications. To facilitate the design of objects that leverage dissolvable support, a custom 3D editor plugin is built that includes a simulation showing how support material dissolves over time. In our evaluation, our simulation predicted geometries that are statistically similar to the physically dissolved samples within 10% error across all samples.<br>by Martin Nisser.<br>S.M.<br>S.M. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Blackwell, Bryan E. (Bryan Ellis). "A framework for determining the mechanical properties of dissimilar material joints." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11245.
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Fu, Xinkai. "Assessing byproduct mining and metal recycling as indicators of material criticality." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123618.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 170-184).<br>The development of advanced technologies relies on using a broader suite of elements from the periodic table, and many agree that the future availability of a set of 'critical materials' is an issue of global concern. However, assessments of material criticality are often overly general, leading to excessive concerns by policy makers and market participants. A quantitative and detailed investigation for supply risk indicators is necessary to further understand the risk associated with specific materials. This thesis investigates two aspects related to material criticality: 1) the status of a metal being produced as a byproduct; 2) The market impact of increased metal recycling. To identify the type of major risks associated with a byproduct metal, a techno-economic analysis is performed on 42 carrier-byproduct metal pairs, by employing cluster analysis and econometric modelling.<br>Contrary to conventional view, it is found in several case studies that the availability of a byproduct metal is not directly limited by carrier supply, but rather limited by the lack of incentive to improve recovery efficiencies. Therefore, developing alternative extraction processes with high recovery rate is proposed as a mitigation strategy for byproduct metals. The economic feasibility of such processes is examined, first in a screening assessment and then in a detailed case study for extracting indium as byproduct of zinc. It is demonstrated that an alternative process could significantly increase byproduct supply, by up to 10% in the case of indium. A bottom-up copper market simulation system is developed by modeling the behaviors of market participants, to estimate the market impact of increased metal recycling. Results from the simulation demonstrates the existence of various rebound effects for primary copper production.<br>Depending on the size and duration of secondary supply shocks, these rebound effects can offset 50% to 90% of the environmental benefits of recycling. In terms of carrier recycling impacting byproduct supply, it is shown that recycling as carrier metal supply risk mitigation strategy would not significantly hurt the availability of byproduct metal.<br>by Xinkai Fu.<br>Ph. D.<br>Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering
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Abdollahi, Sara. "Bioglass 45S5 transformation and molding material in the processing of biodegradable poly-DL-lactide scaffolds for bone tissue engineering." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107628.
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When bone is damaged, a scaffold can temporarily replace it in the site of injury and incite bone tissue to repair itself. A biodegradable scaffold resorbs into the body, generating non-toxic degradation products as new tissue reforms; a bioactive scaffold encourages the surrounding tissue to regenerate. In the present study, we make composite biodegradable and bioactive scaffolds using poly-DL-lactide (PDLLA), a biodegradable polymer, and incorporate Bioglass 45S5 (BG) to stimulate scaffold bioactivity. BG has an interesting trait when immersed in body fluid, a layer of hydroxycarbonate apatite, similar to the inorganic component of bone, forms on its surface. It is of utmost importance to understand the fate of BG throughout the scaffold's processing in order to assess the scaffold's bioactivity. In this study, the established different stages of BG reactivity have been verified by monitoring pH during BG dissolution experiments and by conducting an elemental analysis using inductively coupled plasma optical emission spectroscopy (ICP-OES). The composite scaffolds are synthesized by the solvent casting and particulate leaching technique and their morphology assessed by scanning electron microscopy (SEM). To understand the transformations occurred in BG during scaffold synthesis, BG as received, as well BG treated in acetone and water (the fluids involved in scaffold processing) are characterized by Fourier transform infrared (FTIR), and x-ray photoelectron spectroscopy (XPS). The results are then compared with BG extracted from scaffolds after processing. BG has been determined to start reacting during the scaffold processing. In addition, its reactivity is influenced by BG particle size. The study suggests that the presence of the polymer provides a reactive environment for BG due to pH effects.Teflon molds in scaffold fabrication are inert and biocompatibile, but their stiffness presents a challenge during de-molding. Silicone-based and polyurethane molds are attractive because they are flexible. However, there is a possibility that silicone leaches either from the material itself or the agents used to enhance their performance onto the scaffold. The second study in this thesis focuses on different types of such flexible substrates (Sil940, polyurethane, polyether, polydimethylsiloxane). The presence of Si in PDLLA films prepared on each material is inspected using XPS. Films made on all four materials are found to contain Si, indicative of the dissolution of part of the substrate in the film. However, silicon in the Si-containing catalysts used in the synthesis of polyethers is not transferred to samples, when the polyether substrate is plasma coated.<br>Quand l'os est endommagé, une matrice synthétique peut le substituer temporairement et encourager la reconstruction du tissu osseux. Une matrice biodégradable résorbe dans le corps, engendrant des produits de dégradation non toxique alors que de le nouveau tissu se réforme. Dans la présente étude, on fabrique un composé biodégradable et bioactifs en utilisant poly(D,L-acide lactique) (PDLLA), un polymère biodégradable, et en incorporant Bioglass 45S5 (BG) pour stimuler la bioactivité. BG est un verre à base de silice qui lors du contact avec les fluides corporels, se dissout et libère des ions de silice, phosphate, calcium et sodium. Les ions de calcium et phosphate reprécipitent et forment une couche d'hydroxycarbonate apatite sur la surface du BG, qui ressemble le composant inorganiques de l'os. Puis, la couche d'hydroxycarbonate apatite s'intègre avec le collagène fibrillaire des tissus environnants, le composant organique de l'os, pour former une matrice qui attire les ostéoblastes et stimule l'accroissement du tissu osseux. Ce composite biosynthétique est développé avec la méthode de fusion du sel et sa morphologie est déterminée avec la microscopie électronique à balayage (MEB). Pour évaluer la bioactivité de l'échafaudage, il est important de comprendre le sort du BG durant la production de la matrice. Les différents stages de la réactivité du BG ont été vérifiés en surveillant le pH durant la dissolution du BG et conduisant une analyse élémentaire par la spectrométrie d'émission optique à plasma à couplage inductif (ICP-OES). Pour comprendre les transformations du BG lors de la synthèse des matrices, le BG tel que reçu avec le BG traités dans l'acétone et l'eau (les fluides impliqués dans la procédure de la synthèse) sont caractérisées avec la spectroscopie infrarouge à transformée de Fourier (FTIR) et la spectrométrie photoélectronique X (XPS). Les résultats sont par la suite comparés aves ceux du BG extrait des matrices. Nous avons déterminées que BG réagit durant la préparation de la matrice. De plus, la réactivité du BG est influencée par la grandeur ses particules. La présence du polymère crée un milieu réactif pour le BG, ce qui est due à l'effet du pH. La moule en Teflon utilisée dans la fabrication des matrices biosynthétique est inerte et biocompatible, mais aussi rigide, ce qui peut être problématique durant l'extraction. Ceci engendre une autre investigation qui implique la recherche d'une moule malléable pour faciliter l'enlèvement de la matrice. Les moules à base de silicone et polyuréthane sont attirantes parce qu'elles sont flexibles. Pourtant, il y a une possibilité que la silicone qui fait partie du matériel ou présent dans les produits utilisées pour augmenter sa performance se retrouve sur le produit final. Une deuxième étude dans la présente thèse est donc consacrée sur différents substrats flexibles (Sil940, polyuréthane, polyéther, polydimethylsiloxane). Le XPS est utilisé pour inspecter des films de PDLLA produit sur chaque matériel. La silicone est présente dans les films préparés sur tous les quatre matériaux. Cependant, lorsque le plasma est appliqué pour recouvrir le polyéther, la silicone présente dans les catalyses utilisées pour sa fabrication n'est pas transmises sur celui-ci. Donc le polyéther traité avec le plasma est convenable pour la fabrication des matrices biosynthétiques extracellulaires.
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Freeman, Julie. "Defining data as an art material." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/31793.
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Digital technology, and speci cally digital data, forms the backbone of nearly all our communications including machine to machine, human to machine, and, increasingly, human to human. It is unsurprising that one of the most prevalent materials of our time is used by artists to create work. This thesis defines data as an art material. It investigates the variety of manifestations of data when used in art, through the review of existing artwork and the development of new artworks and visualisations that use a dataset collected for this research. Through the lens of conceptualising data as an art material, a definition and manifesto of data art is put forward (Chapter 2). In addition, a taxonomy for describing data as an art material is proposed and its usage explored by applying it to a number of data art descriptions and by analysing a database of data artworks tagged with relevant terms (Chapter 3). Temporal, biological, and real-time, terms from the taxonomy, are particularly relevant to the way in which digital technology mediates our connection to nature. To explore these forms of data within artwork, a collaboration with Dr Chris Faulkes, Reader in Evolutionary Ecology, facilitated the design and implementation of an electronic system to collect data from a colony of animals. Chapter 4 describes the tracking system which resulted in a real-time stream of biological temporal data. Translations of this data are explored in more detail through the practical application of various computational techniques including scientific analysis (Chapter 5), animation, sonification, data visualisation (Chapter 6) and soft robotic objects (Chapter 7). The thesis demonstrates that an inanimate object, animated through the translation of data, can have a body language through which to effectively convey characteristics of living things (Chapter 8). Finally, public engagement events are presented in Chapter 9, with reflections, contributions and future work concluded in Chapter 10.
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Khojandi, Aryan Iden. "Efficient MCMC inference for material detection and classification In tomography." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/113183.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016<br>Page 106 blank. Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 103-105).<br>Inferring the distribution of material in a volume of interest based on tomographic measurements is a ubiquitous problem. Accurate reconstruction of the configuration is a daunting task, especially when the sensor setup is not sufficiently comprehensive. The inverse problem corresponding to this reconstruction task is almost always ill-posed, but reasoning about the latent state remains possible. We investigate the problem of classifying volumes into object classes, using the latent configuration as an intermediate representation. We use the framework of Probabilistic Inference to implement MCMC sampling of realizations of the latent configuration conditioned on the measurements. We exploit conditional-independence properties of the graphical-model representation to sample many nodes in parallel and thereby render our sampling scheme much more efficient. We then reason over the samples and use a neural network to classify them. We demonstrate that classification is far more robust than reconstruction to the removal of sensors and interrogation angles. We also show the value of using the intermediate representation and a generative physics-based forward model by comparing these classification results with those obtained by foregoing the latent space and training a classifier directly on the sensor readings. The former benefits from regularization of the posterior distribution, allowing it to learn more rapidly and thereby perform significantly better when the number of labeled examples is limited, a reality present in the context of our problem and in many others.<br>by Aryan Iden Khojandi.<br>M. Eng.<br>M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Ewart, Ian James. "An anthropology of engineering." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:69c42210-e6c0-49c7-bec2-4a27f2e9903c.
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This dissertation considers the place in anthropology of ‘production’ generally, and ‘engineering’ specifically, by asking the simple question: How do people make things? Scholars of material culture have until recently focused on issues of consumption, especially the consumption of commodities (Miller), and considered production only in the abstract. Other theoretical approaches are therefore drawn upon to act as a framework for the thesis, including network theory (Law and Latour), and environmental relationism (Ingold). A methodology of ‘parallel fieldwork’ was developed (from Bourdieu), to situate myself as an experienced engineer carrying out anthropological fieldwork. Work in a ‘familiar’ environment (the Didcot Railway Centre, UK) was used to provoke thoughts about engineering in my primary fieldsite (the Kelabit highlands, Borneo). Data from the UK thus helped frame my analysis of Kelabit engineering, presented here in four parts. First, using the construction of two bridges as a case study, I suggest that a design can be seen as the revelation of a potential future, rather than a complete plan, as is suggested by design researchers such as Lawson and Norman. Then, by looking at changing traditions of house-building, I demonstrate the intimate relationship between materials and environment, even as the environment becomes more industrialised (Tsing), and consider this example in the light of debates about materiality (Miller; Ingold). Personal involvement in the conception and building of a new suspension bridge allowed me to investigate in some depth the act of construction. As a communal project, this incorporated aspects of individual skill, in the way that Ingold has described, but also the organization of people, tools and materials, akin to Law’s ‘heterogenous engineering’. This leads me to conclude that a theory of engineering might come from due consideration of both these approaches to relational thinking. Finally, I describe an abandoned longhouse and trace its deconstruction, suggesting that this is an example of creative destruction (Colloredo-Mansfeld), and re-materialization (Gregson). The dissipation of the material parts of the building shows that engineered objects should be seen as an ongoing process of material creation and disposal, and not a unified whole. In conclusion, my hope is that this dissertation contributes to ideas about the place and nature of material culture, and advocates a more prominent place for ‘production’ within anthropology.
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Hultén, Leo, and Philip Jansson. "Investigation and Evaluation of Metal Powder Characterization Techniques : Currently available at the KTH Department of Material Science and Engineering." Thesis, KTH, Materialvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231469.
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The KTH Department of Materials Science and Engineering has lacked powder metallurgy research for many years, and as this field is constantly gaining in importance, such research needs to be reestablished. This requires the department to be able to accurately and efficiently characterize the properties of a powder, such as size distribution and composition, and in the short term, this needs to be done using non-specialized equipment. This project aimed to assess the availability and usefulness of both traditional and novel characterization methods by way of trial characterization experiments as well as a literature review. The experiments resulted in some data about three sample powders, as well as the conclusions that size distribution could be effectively characterized by automatized image analysis, composition could be characterized using Energy Dispersive X-ray Spectroscopy and that sample preparation was key to good results. It was concluded that the department could conceivably evaluate the most important properties, but that sampling and sample preparation routines need to be established to ensure efficient characterization and representative data.<br>Materialinstitutionen på Kungliga Tekniska högskolan har i många år helt saknat pulvermetallurgiforskning och eftersom detta fält ständigt blir mer relevant behöver denna forskning återetableras. Detta kräver att institutionen med tillräcklig noggrannhet och effektivitet kan bestämma egenskaper hos ett pulver, såsom storleksfördelning och sammansättning, och på kort sikt behöver detta ske med ickespecialiserad utrustning. I detta projekt har tillgänglighet och användbarhet hos både traditionella och innovativa analysmetoder utvärderats med hjälp av experimentell karaktärisering av pulver samt en litteraturstudie. Experimenten gav data om de tre undersökta pulvren och resulterade även i slutsatsen att storleksfördelning kunde bestämmas med automatiserad bildanalys, att samansättning kunde bestämmas med Energi Dispersiv Röntgen Spektroskopi och att provpreparering äravgörande för bra resultat. Av detta följer att institutionen rimligtvis kan bestämma de viktigaste egenskaperna hos ett pulver, men att rutiner för provtagning och provpreparering behöver etableras för att säkerställa effektiv analys och representativ data.
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Dunand, D. C. (David C. ). "Mechanics and structure of dislocations induced by thermal mismatch in composite material." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13692.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1991.<br>Includes bibliographical references (leaves 231-235).<br>by David Christophe Dunand.<br>Ph.D.
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Hwang, Samuel James. "DNA as a programmable material : de novo gene synthesis and error correction." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44423.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.<br>Includes bibliographical references (leaves 42-43).<br>Deoxyribonucleic acid (DNA), the polymeric molecule that carries the genetic code of all living organisms, is arguably one of the most programmable assembly materials available to chemists, biologists, and materials scientists. Scientists have used DNA to build many different structures for various applications in disparate areas of research from traditional biological applications to more recent non-biological applications. Although DNA isn't typically thought of as an assembly material by people not doing research in the area, the availability of decreasing cost synthetic oligonucleotides has led to advances in gene fabrication technology which in turn has enabled synthetic biology to flourish. Using DNA as a building material for small and large constructs of DNA is reliant on having effective gene synthesis techniques. Construction of synthetic DNA is limited by errors that pervade the final product. To address this problem, effective error correction methods are pivotal. Having extremely robust gene synthesis and error correction techniques will allow researchers to generate very large scale constructs potentially necessary in applications such as genome re-engineering.<br>by Samuel James Hwang.<br>S.M.