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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
421

Physical chemistry of carbothermic reduction of alumina

Frank, Robert A January 1985 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1985. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Vita. / Bibliography: leaves 177-180. / by Robert A. Frank. / M.S.
422

Electrical properties and defect structure of UO2-CeO2 solid solutions

Stratton, Thomas George January 1984 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Vita. / Includes bibliographical references. / by Thomas George Stratton. / Ph.D.
423

Fatigue properties of rail steels

Journet, Bertrand January 1983 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1983. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Bertrand Journet. / M.S.
424

Load deflection analysis for determining mechanical properties of thin films with tensile and compressive residual stresses

Bulsara, Mayank T. (Mayank Thakordas) January 1995 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1995. / Includes bibliographical references (leaves 24-25). / by Mayank T. Bulsara. / M.S.
425

Constrained and unconstrained growth : applying the Avrami Equation to the production of materials / Applying the Avrami Equation to the production of materials

See, Marianna B. (Marianna Blackman) January 2013 (has links)
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (p. 51-52). / Production of materials which are limited by the amount available on the earth's surface follow a growth curve similar to the Avrami equation which governs the process of nucleation and growth. This thesis will analyze whether the product curve follows not only the same path but the same steps as the Avrami model: initially slow growth during an introductory period, accelerated growth during market acceptance, and declining growth following market saturation. This thesis will use two materials, steel and aluminum, as a case study to further understand the applicability of the Avrami model to production forecasts of materials available in finite or limited amounts. The aim of this project was to provide producers of various materials a model to use to predict when it would be profitable to invest in and enter a market and when not to do so. The framework developed provides a well-behaved model for the initial two stages, introduction and market acceptance, and forecasts the transition point between those two stages. However, due to lack of current data as neither aluminum nor steel have reached market saturation, a fit for the final stage and a forecast for the transition from market acceptance to market saturation has not yet been determined. / by Marianna B. See. / S.B.
426

Excess thermodynamic properties and size-dependent segregation phenomena in ultrafine-grained titanium dioxide

Terwilliger, Chrysanthe D., 1966- January 1993 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1993. / Vita. / Includes bibliographical references (leaves 117-128). / by Chrysanthe D. Terwilliger. / Ph.D.
427

Understanding the catalytic activity of oxides through their electronic structure and surface chemistry

Stoerzinger, Kelsey A. (Kelsey Ann) January 2016 (has links)
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references. / The intermittent nature of renewable energy sources requires a clean, scalable means of converting and storing energy. Water electrolysis can sustainably achieve this goal by storing energy in the bonds of oxygen and hydrogen molecules. The efficiency of this storage-conversion process is largely determined by the kinetic overpotential required for the oxygen evolution and reduction reactions (OER and ORR), respectively. This thesis focuses on transition metal oxides as alternative oxygen catalysts to costly and scarce noble metals. In order to develop descriptors to improve catalytic activity, thus reducing material cost for commercial technologies, this work studies fundamental processes that occur on model catalyst systems. Electrochemical studies of epitaxial oxide thin films establish the intrinsic activity of oxide catalysts in a way that cannot be realized with polydisperse nanoparticle systems. This thesis has isolated the activity of the catalyst on a true surface-area basis, enabling an accurate comparison of catalyst chemistries, and also revealed how different terminations and structures affect the kinetics. These studies of epitaxial thin films are among the first to probe phenomena that are not straightforward to isolate in nanoparticles, such as the role of oxide band structure, interfacial charge transfer (the "ligand" effect), strain, and crystallographic orientation. In addition, these well-defined surfaces allow spectroscopic examinations of their chemical speciation in an aqueous environment by using ambient pressure X-ray photoelectron spectroscopy. By quantifying the formation of hydroxyl groups, we compare the relative affinity of different surfaces for this key reaction intermediate in oxygen electrocatalysis. The strength of interaction with hydroxyls correlates inversely with activity, illustrating detrimental effects of strong water interactions at the catalyst surface. This fundamental insight brings molecular understanding to the wetting of oxide surfaces, as well as the role of hydrogen bonding in catalysis. Furthermore, understanding of the mechanisms of oxygen electrocatalysis guides the rational design of high-surface-area oxide catalysts for technical application. / by Kelsey A. Stoerzinger. / Ph. D.
428

Design and implementation of top-contact light-emitting diodes integrated on silicon

Lazo, Nicole Danielle B. (Nicole Danielle Bautista) January 1994 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994. / Includes bibliographical references (leaves 47-48). / by Nicole Danielle B. Lazo. / M.S.
429

Thermodynamic data from multi-component metallic diffusion couples

Imai, Tadashi, 1963- January 1997 (has links)
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997. / Vita. / Includes bibliographical references (leaves 288-290). / by Tadashi Imai. / Sc.D.
430

Fundamental understanding and design principles of oxide/metal surfaces for lithium storage

Lu, Yi-Chun, Ph. D. Massachusetts Institute of Technology January 2012 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student submitted PDF version of thesis. / Includes bibliographical references (p. 140-149). / Lithium-battery technologies have promising potentials to enable efficient energy distribution, sustainable transportation systems, and the widespread of renewable energy. One of the most critical challenges that limits their further advances is the limited ability to design efficient interfacial and surface chemistries due to the lack of fundamental understanding of reaction mechanisms. This thesis aimed to develop the fundamental understanding and design principles of oxide and metal surfaces for conventional Li-ion batteries and next generation, high-energy Li-air (or Li-O2) batteries. Fundamental approaches involving electrochemical characterizations, advanced spectroscopic and microscopic techniques were used to probe the interfacial and surface reactions of these batteries. The criteria for efficient electrode-electrolyte interfaces for Li-ion batteries were identified by examining the working mechanism of "AlPO4" nanoparticle coatings on enhancing the cycle life and energy efficiency of LiCoO2 batteries. SEM, XRD and XPS revealed that the "AlPO4" nanoparticles promote the formation of Co-Al-O-F species on the LiCoO2 particle surfaces as protection layers against electrolyte decomposition and oxygen loss from the lattice. This highlights the importance of metal oxyfluoride species toward material stability and cell efficiency. The reaction kinetics, catalyst effects and reaction mechanism of Li-O2 batteries were investigated by developing electrochemical model systems i.e., rotating disk electrode and Li2O2-filled composite electrodes, to quantify the intrinsic catalytic activity of nonaqueous oxygen reduction (ORR) and oxygen evolution reactions (OER). We found that the Li+-ORR activity is in order of Pd > Pt > Ru ~ Au > C, exhibiting a volcano-type dependence as a function of the oxygen adsorption energy of the catalyst surface. This volcano dependence suggests that the oxygen adsorption energy of the catalyst can serve as the ORR activity descriptor for designing highly active ORR catalyst for Li-O2 batteries. In addition, the application of Au nanoparticles was found to significantly increase the rate capability of the Li-O2 cells by enhancing the intrinsic ORR activity and influencing the structures of the discharge products. The catalyst effects on the charge reaction (OER), or Li2O2-decomposition reaction, were studied by potentiostatically oxidizing the Li2O2-filled composite electrodes with various catalysts. It is found that the electro-oxidation of Li2O2 can be significantly catalysed by the presence of Pt/C. With insights obtained from the model system studies, we designed bimetallic PtAu nanoparticles as bifunctional catalysts for Li-O2 batteries. Interestingly, the PtAu/C catalyst exhibits similar discharge profile to the Au/C and mirrors the charge activity of the Pt/C catalyst, achieving a remarkable round-trip efficiency (~75%) for rechargeable Li-O2 batteries. / by Yi-Chun Lu. / Ph.D.

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