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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.
1

Fluid dynamics and heat transfer considerations for gel thermal interface materials (part 1) and the underfill process (part 2)

Davidson, Drew Alan. January 2006 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Mechanical Engineering Department, 2006. / Includes bibliographical references.
2

Structural defects and properties of multicomponent materials

Bellou, Aikaterini. January 2009 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, December 2009. / Title from PDF title page (viewed on Dec. 9, 2009). "College of Engineering and Architecture." Includes bibliographical references.
3

Binder-Free Composite Electrodes for Energy Storage Devices Using Networks of Carbon Nanotubes as a Multifunctional Matrix

Unknown Date (has links)
The improvement of electrical energy storage (EES) devices such as batteries and electrochemical capacitors (ECs) is crucial to the widespread adoption of electric drive vehicles and the increased mobility of portable electronics. This research takes a unique approach to the improvement of EES devices through the investigation of a novel nanocomposite system to improve the performance of particle based electrodes. The majority of commercially available batteries and ECs have electrodes fabricated from a powder of fine particles (typically with particle sizes on the order of several µms). There is a severe lack of options for transforming these powders into usable electrodes. The traditional electrode fabrication method is to mix the active material powder with a polymer binder to form a sheet or film, which can then be implemented into the device. However, reliance on and incorporation of the polymer binder introduces several disadvantages and performance limitations. In this research, porous networks of carbon nanotubes (CNTs) are investigated to replace the polymer binder in the fabrication of particle based electrodes for electrochemical devices. The multifunctional CNT networks provide the supporting structure and electron conduction pathways to create freestanding and flexible composite electrodes with high electrical conductivities (50 - 100+ S/cm). Two case studies were carried out to explore the properties and performance of the new electrode structure: 1) Activated carbon (aC) particle based electrodes for electrochemical capacitors and 2) Silicon (Si) particle based electrodes for lithium-ion batteries. Samples were fabricated and characterized with an emphasis on obtaining processing-structure-property relationships to guide further development of these unique nanocomposite materials. The aC-CNT electrodes showed specific capacitances of ~50 F/g (in 6M KOH) with less than 10% capacitance loss after 30,000 cycles; demonstrating the ability of the CNT networks to maintain structural integrity during operational conditions. Si-CNT electrodes had high coulombic efficiencies (> 90%) and initial reversible capacities of over 2000 mAh/g. Additionally, fundamental issues are addressed such as possible electrode failure mechanisms and the limits of particle weight fractions that are achievable. Knowledge of the maximum weight fraction of particles obtainable within the CNT networks is important to determine the feasibility of the electrodes for commercial use. A volume-fraction-limited phenomenon is proposed for the mechanism of the particle loading limit and discussed with supporting evidence. / A Thesis submitted to the The Graduate School in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2010. / November 12, 2010. / carbon nanotube, binder-free, nanocomposite, electrode, battery / Includes bibliographical references. / Zhiyong Liang, Professor Directing Thesis; Tao Liu, Committee Member; Hsu-Pin Wang, Committee Member; Jianping Zheng, Committee Member.
4

PP2A and Casein Kinases Regulate SWE1 Degradation Through HSL1 and HSL7

Unknown Date (has links)
In mammalian cells, cyclin dependent kinase (CDK) is subjected to negative regulation by a conserved kinase, Wee1. In budding yeast, S. cerevisiae, Swe1 kinase, the Wee1 homologue, phosphorylates and inactivates Cdk1 associated with mitotic cyclins to prevent entry into mitosis. Both transcription and proteolysis ensure the periodic appearance of Swe1 protein during the cell cycle. To facilitate Swe1 protein degradation, the functional Hsl1-Hsl7 protein complex recruits Swe1 to the bud-neck. As a kinase, Hsl1 phosphorylates Hsl7 directly and this phosphorylation is essential for Swe1 degradation. Hsl1 itself is also a phosphoprotein and Elm1 kinase has been shown to be responsible for Hsl1 phosphorylation. Protein phosphatase 2A (PP2A) is a critical phosphatase involved in multiple cellular events. Previous work indicates that the absence of the B-regulatory subunit Cdc55 results in accumulation of Swe1 protein, which leads to the abnormal bud morphology. We present evidence indicating that the failure of Swe1 degradation in cdc55 mutants is a consequence of defective Hsl1-Hsl7 pathway. We found that the phosphorylation of both Hsl7 and Hsl1 deceased obviously in cdc55 mutant, suggesting the compromised kinase activity of Elm1. Moreover, casein kinases are also required for the phosphorylation and activation of Hsl1. / A Thesis submitted to the Department of Biomedical Science in partial fulfillment of the requirements for the degree of Master of Science. / Degree Awarded: Summer Semester, 2010. / Date of Defense: July 15, 2010. / PP2A, Cdc55, Yck1, Yck2, Swe1 / Includes bibliographical references. / Yanchang Wang, Professor Directing Thesis; Wuming Deng, University Representative; Mary Hurt, Committee Member; Akash Gunjan, Committee Member; Hongguo Yu, Committee Member.
5

Fabrication of hierarchical porous materials by templating particle-stabilized high internal phase emulsions.

January 2012 (has links)
分層次的多孔材料在自然界中非常廣泛的被發現,例如動物的肺部、樹葉以及矽藻的骨骼。最近一些年,大孔(macropores)連同介孔(mesopores)或者(或與)微孔(micropores)等結構的分層次的多孔材料的製備與合成吸引了材料化學領域諸多的注意力,以期他們在催化、吸附解附、藥物釋放、感測器以及組織工程等多種方向中發揮潛在的應用。 / 本論文中我們將介紹一種簡單而靈活的的基於微粒穩定的高內相乳液(Particle-stabilized high internal phase emulsion)的方法,製備得到具有分層次多孔結構的二氧化鈦材料,擁有增強的光催化活性。由微凝膠軟球和二氧化鈦硬球共同作用,我們得到穩定的水包油高內相乳液體系。在除去液體相時將會促使形成幾十微米的大孔結構,約十微米的介孔連通窗格,以及分佈在大孔壁上的約一百納米的微孔,這三種不同尺寸的孔隙結構在三維方向上互相連通。初始合成的二氧化鈦材料由掃描電子顯微鏡(SEM),X射線衍射(XRD),壓汞儀來表徵其内部結構,同時測試其相對應的羅丹明光降解效率。結果清晰地顯示,微粒穩定的範本法可以成功的形成擁有多種且互不相同的多層次多孔結構。同時這種具有大孔和微孔的多層次孔隙結構的二氧化鈦材料,表現出非常有效的光化學催化性質,顯示了其在分離、淨化等過程的巨大潛在應用價值。 / Hierarchical porous materials occur widely in nature, including for example the lungs of animals, the leaves of trees, and diatom skeletons. In recent years, the synthesis of new hierarchical porous materials containing macroporous along with micro-and/or mesoporous has attracted considerable attention in material chemistry, because of their potential use in diverse applications such as catalysis, adsorption and separations, drug delivery, sensors and tissues engineering. / In this thesis, we present a simple and flexible method to synthesize hierarchically porous structured titania with enhanced photocatalytic activity using particle-stabilized high internal phase emulsions (Pickering HIPEs). Starting with a highly concentrated emulsion stabilized by both soft microgels and TiO₂solid nanoparticles, three-dimensionally interconnected porous titania materials with ordering on three different scales, that is, macroporous (~50μm), interconnected throat (~10μm), and nanoporous walls (~100 nm), are successfully obtained after drying and sintering. The so-prepared materials are characterized by scanning electron microscopy (SEM), X-ray diffraction, mercury intrusion, and the corresponding photocatalytic activity is evaluated by measuring the photodegradation of Rhodamine B in water. Our results clearly show that particle-stabilized emulsion templating can successfully lead to hierarchical porous material with multiple and discrete pore scales. Moreover, these hierarchically porous TiO₂ containing macroporous along with nanopores walls can be very efficient photocatalysts, suggesting their great potential applications in separation and purification process. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Li, Xiaodong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Abstracts also in Chinese. / 摘要 --- p.I / Abstract --- p.II / Tableof Contents --- p.III / Acknowledgement --- p.VI / Chapter Chapter 1 --- Introduction to Porous Materials: Design, Synthesis and Applications --- p.1 / Chapter 1.1 --- Hierarchical Porous Materials in Nature --- p.1 / Chapter 1.2 --- Artificial Hierarchical Porous Materials --- p.2 / Chapter 1.3 --- Non-Templating Methods --- p.3 / Synthesis of Hierarchical Porous Materials with Single Composition --- p.5 / Chapter 1) --- meso-macroporous zirconium oxides --- p.5 / Chapter 2) --- meso-macroporous titanium oxides --- p.6 / Synthesis of Hierarchical Porous Materials with Multiple Composition --- p.9 / Chapter 1.4 --- Templating Methods --- p.10 / Chapter 1.5 --- Combination of Template and Non-template Methods --- p.12 / Chapter 1.6 --- Potential Application of Porous Materials --- p.13 / HPLC separation --- p.13 / Hierarchical catalysis --- p.14 / Electrode materials for fuel cell applications --- p.15 / Biomaterials engineering --- p.15 / Chapter 1.7 --- Objective of the Research --- p.16 / Chapter References --- p.18 / Chapter Chapter 2 --- Preparation of Hierarchically Structured TiO₂ Using High Internal Phase Emulsions (HIPEs) Stabilized by Binary Nanoparticles as the Templates --- p.22 / Chapter 2.1 --- Introduction to Particle Stabilized HIPEs --- p.22 / Chapter 2.2 --- Experiment Part --- p.26 / Chapter 2.2.1 --- Materials --- p.26 / Chapter 2.2.2 --- pNIPAM-co-MAA microgels synthesis and Characterization --- p.26 / Chapter 2.2.3 --- Synthesis of Hierarchical Porous TiO₂ Materials templating from HIPEs Stabilized by Binary Nanoparticles --- p.29 / Chapter 2.3 --- Results and Discussion --- p.32 / Chapter 2.3.1 --- HIPEs Stabilized Solely by Microgel Particles --- p.32 / Chapter 2.3.2 --- HIPEs Stabilized by Binary Nanoparticles --- p.35 / Chapter 1) --- Sintering effect on the porous TiO₂ monolith --- p.40 / Chapter 2) --- Microgel/TiO₂ ratio effect on the porous materials --- p.45 / Chapter References --- p.52 / Chapter Chapter 3 --- Photo-Catalytic Activity of the TiO₂-based Hierarchically Structured Porous Materials --- p.54 / Chapter 3.1 --- Introduction --- p.54 / Chapter 3.2 --- Experiment Section --- p.55 / Chapter 3.3 --- Result and Discussion --- p.56 / Chapter 1) --- Influence of sintering temperature on the porous materials --- p.56 / Chapter 2) --- Influence of internal phase volume fraction on the photocatalytic activity . --- p.59 / Reference --- p.63 / Chapter Chapter 4 --- Conclusion --- p.64
6

Some theoretical and experimental aspects of design with brittle material /

Robinson, Ernest Y. January 1965 (has links)
Thesis (M.S.)--Oregon State University, 1965. / Typescript. Includes bibliographical references (leaves 77-80). Also available on the World Wide Web.
7

Synthesis and characterization of micro- and mesoporous materials for low temperature selective catalytic reduction of nitrogen oxides

Kasongo Wa Kasongo, Jean B January 2011 (has links)
In summary, it has been shown during this study that bimetallic Fe and Mn containing catalysts can be prepared by wet impregnation and not by ion exchange because of the competition between two different metals at different oxidation number. Only a single metallic phase catalyst could be prepared successfully by using ion exchange.
8

Effects of layer waviness on compression-loaded thermoplastic composite laminates /

Adams, Daniel O'Hare, January 1991 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 269-276). Also available via the Internet.
9

Experimental investigations of magnetic and magneto-rheological materials and their rigidification properties /

Glaser, Radek, January 2009 (has links)
Thesis (M.S.) in Mechanical Engineering--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 214-219).
10

Engineering tools for robust creep modeling /

Holmström, Stefan. January 1900 (has links) (PDF)
Thesis (doctoral)--Aalto University, 2010. / Includes bibliographical references. Also available on the World Wide Web.

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