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‣ Fabrication and assembly of micron-scale ceramic components

Tupper, Malinda M., 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 152 p.; 6608785 bytes; 6608593 bytes; application/pdf; application/pdf
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The micron-scale manufacturing industry has grown to hundreds of billions of dollars since the advent of the transistor in 1947. Increasing demands for integration of surface mount components, greater use of portable electronic devices, and miniaturized medical diagnostic devices have given rise to the need for methods of fabricating and assembling micron-scale discrete components. Development of reliable non-contact assembly methods requires thorough understanding of electro-mechanics, surface adhesion, and gravitational forces acting on micron- scale objects. The impact of such a study will spread beyond microelectronics, and will also have broad significance in the development of micro-electromechanical systems (MEMS) for diverse applications such as biological assays, drug delivery devices, and tools for high throughput combinatorial materials development. This thesis will discuss methods for and challenges in fabrication, manipulation, and assembly of discrete micron-scale objects. The impact of these issues will be illustrated for the development of a micro-dispensing system used to manipulate microgram quantities of dry granular substances for combinatorial materials development. This method provides a model system to explore the forces on micron-scale objects...

‣ Evaporative printing of organic materials and metals and development of organic memories

Kang, Sung Hoon, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 132 p.; 6180072 bytes; 6197163 bytes; application/pdf; application/pdf
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The advantages of directed printing make it the ideal fabrication tool for the ubiquitous electronic technologies of the future. However, direct printing techniques such as ink-jet technology, are currently limited to materials that can be processed in solution. We developed a novel micro-machined print head capable of expanding the capabilities of inkjet printing to metals and molecules that are suited for evaporative deposition. Deposition of metals is particularly desirable advantage of the proposed printer. We demonstrate arbitrary organic and metal patterns by printing, with the line width modulated by controlling the micro-machined shutter. With the challenges and solutions for ambient pressure printing are also studied. Additionally, the printer can be used for organic crystal formation, and controlled doping. In the second part of the thesis we examine charge trapping and storage in organic thin film devices. We demonstrate that by controlled doping, we can engineer charge storage in active organic electronic devices. Charge trapping in organic hetero-junction structures results in two distinct phenomena that both manifest as a memory behavior. Trapped charge can (1) increase the carrier mobility in organic structures, (2) generate current during the de-trapping process. Both processes are demonstrated in practical structures.; by Sung Hoon Kang.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Size dependence of mechanical responses of materials in small-volume structures

Choi, Yoonjoon, 1967-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 144 p.; 5514870 bytes; 9747528 bytes; application/pdf; application/pdf
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The effect of length scales on mechanical responses of materials in small-volume structures, such as thin films and patterned lines on substrates, is examined. The understanding of stress evolution and deformation behavior of those materials is one of major factors in the fabrication, performance, and reliability of microelectronic devices. The length scales involved in such materials are on the order of 1 min., and the deformation characteristics of the materials exhibit a strong dependence on their physical size such as film thickness and line width, as well as their microstructural length scale such as grain size. In this thesis, analytical, experimental, and computational approaches are utilized to elucidate the effect of length scales on the time-independent inelastic deformation of materials in small-volume structures. Experiments focus on continuous thin films and patterned lines of Al on Si substrates. The inelastic deformation of a material can be described by parameters which range from global constitutive (stress-strain) relations to atomistic descriptions of defect generation. An analytical model based on the generation of an array of dislocation loops is used to rationalize the film-thickness and grain-size effect on the stress evolution of thin metallic films on thick substrates. The consequence of the dislocation generation restricted by the film thickness and grain size leads to the full description of stress-temperature histories in an Al film on a Si substrate...

‣ Structure and properties of hydrogen and covalently bonded side group liquid crystalline block copolymers

Osuji, Chinedum, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 226 leaves; 11367870 bytes; 22199544 bytes; application/pdf; application/pdf
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Diblock copolymers incorporating liquid crystallinity via a lateral attachment of mesogenic species to a flexible backbone were studied for their microstructure-property relationships. Two families of materials were studied, distinguished primarily by the method of attachment of the mesogen to the polymer. In the first, azobenzene based mesogens were covalently tethered to the isoprene blocks of a poly(styrene)-block-poly(isoprene), P(S-b-ILC), series of diblock copolymers. In the second family of polymers, hydrogen bonding was used to complex bi-phenyl based mesogens to the acrylic acid units of a poly(styrene)-block-poly(acrylic acid), P(S-b-AA) diblock copolymer. The morphology of the P(S-b-ILC) system was characterized as a function of composition, and clear correlations between the microphase separated structure and the thermal properties of the liquid crystalline mesophase were observed and accounted for. Control of the hierarchical structure in these materials was pursued and achieved independently via surface epitaxy, oscillatory shear and, for the first time in this class of materials, via magnetic fields. It was found that the morphology adopted by the material under the external fields is strongly dependent on the orientation of the liquid crystalline mesophase with respect to the inter-material dividing surfaces present due to the microstructure. Oscillatory shear of a P(S-b-ILC) resulted in the first observation of a novel transverse cylindrical microdomain morphology in one case. The investigation of hydrogen-bonded side-group liquid crystalline block copolymers based on P(S-b-AA) followed a screening of several other candidate host diblock-mesogen pairs. The structure and thermal properties of a model P(S-b-AA) diblock and a homopolymer acrylic acid complexed with mesogens were studied and characterized as a function of composition. A high molecular weight analogue...

‣ Chemical functionalization of AFM cantilevers; Chemical functionalization of atomic force microscopy cantilevers

Lee, Sunyoung, S.M. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 52 p.; 3055388 bytes; 3056447 bytes; application/pdf; application/pdf
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Atomic force microscopy (AFM) has been a powerful instrument that provides nanoscale imaging of surface features, mainly of rigid metal or ceramic surfaces that can be insulators as well as conductors. Since it has been demonstrated that AFM could be used in aqueous environment such as in water or various buffers from which physiological condition can be maintained, the scope of the application of this imaging technique has been expanded to soft biological materials. In addition, the main usage of AFM has been to image the material and provide the shape of surface, which has also been diversified to molecular-recognition imaging - functional force imaging through force spectroscopy and modification of AFM cantilevers. By immobilizing of certain molecules at the end of AFM cantilever, specific molecules or functionalities can be detected by the combination of intrinsic feature of AFM and chemical modification technique of AFM cantilever. The surface molecule that is complementary to the molecule at the end of AFM probe can be investigated via specificity of molecule-molecule interaction.; (cont.) Thus, this AFM cantilever chemistry, or chemical functionalization of AFM cantilever for the purpose of chemomechanical surface characterization...

‣ Breaking symmetries in ordered materials : spin polarized light transport in magnetized noncentrosymmetric 1D photonic crystals, and photonic gaps and fabrication of quasiperiodic structured materials from interference lithography

Bita, Ion
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 219 leaves
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Effects of breaking various symmetries on optical properties in ordered materials have been studied. Photonic crystals lacking space-inversion and time-reversal symmetries were shown to display nonreciprocal dispersion relations, and to exhibit a remarkable set of symmetry-related properties. Even in 1D, these materials are found to display indirect photonic band gaps, backward wave propagating modes (antiparallel phase and group velocities) which enable negative refraction at the air-crystal interface, ability to allow bending light with perpendicular magnetic fields, unidirectional superprism effects, etc. By calculating the complex photonic band structure, we show that the gap modes differ fundamentally from the commonly assumed evanescent modes with purely imaginary wave vectors - solely due to symmetry, we show that the gaps of nonreciprocal photonic crystals have complex wave vectors with both imaginary components and non-zero, frequency dependent real components. This basic finding is further studied in the context of tunneling dynamics, by considering the problem of tunneling time for nonreciprocal photonic band gap barriers (the tunneling wave packet has an energy in the middle of the gap).; (cont.) It was found that the classical Hartman effect (independence of tunneling time on barrier length...

‣ Commercialization of Quantum Dot White Light Emitting Diode technology; Commercialization of QD WLED technology

Zhao, Xinyue, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 54 leaves
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It is well known that the use of high-brightness LEDs for illumination has the potential to substitute conventional lighting and revolutionize the lighting industry over the next 10 to 20 years. However, successful penetration of this extremely large lighting market would require vast improvements in power conversion efficiencies, color index, light output per device and drastic reduction in cost. Quantum Dot white LED (QD WLED) technology may be one of the best choices, due to its higher energy efficiency, larger color render in index, better versatility and more importantly lower cost, compared to conventional blue LED plus YAG: Ce yellow phosphor technology. Due to the fundamental difference of the material structure, QD LEDs will win a steady position among existing white LED patents and a hybrid fabless plus IP business model has the best position to promote this technology to maximize its benefits and potential for the entire LED industry.; by Xinyue Zhao.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.; Includes bibliographical references.

‣ An analysis of MRAM based memory technologies

Vijayaraghavan, Rangarajan, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 69 leaves
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MRAM is a memory (RAM) technology that uses electron spin to store information. Often been called "the ideal memory", it can potentially combine the density of DRAM with the speed of SRAM and non-volatility of FLASH memory or hard disk, and all this while consuming a very low amount of power. However, it is the need for a fast and non-volatile computer memory that has been the key driver for evolution of this technology. At the moment, MRAM is in its final stages of development and much of the current research concentrates on issues like reducing the write current, increasing the density and making the process more reproducible. A lot of companies are pursuing research on this technology and are likely to introduce it into the market in the near future. However, it will be a while before MRAM can replace conventional memories. Nevertheless, since MRAM can resist high radiation, and can operate in extreme temperature conditions, it is likely that we will see the first MRAM in applications that need such properties.; by Rangarajan Vijayaraghavan.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.; Includes bibliographical references (leaves 66-68).

‣ Micromachined printheads for the direct evaporative patterning of organic materials

Leblanc, Valérie, Ph. D. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 139 p.
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Organic optoelectronic devices are appealing for low-performance applications on very low cost and flexible substrates, due to their low-temperature processing. However, it still remains a challenge to develop suitable fabrication techniques to pattern organic thin films on low-cost, large-area substrates. The two techniques used commercially are inkjet printing of polymers, which limits the morphology and performance of devices, and shadow-masking of vacuum sublimation for small molecule materials, which is not scalable to large-area substrates. In this thesis, we investigate the use of MicroElectroMechanical Systems (MEMS) to provide new ways of patterning organic materials deposited by an evaporative process. We present the design, fabrication, modeling and characterization of two generations of micromachined printheads developed to expand the possibilities of printing of organic optoelectronics. The design and fabrication of a compact electrostatic actuator enabling the first generation of printhead is first presented. It is then used to actuate a microshutter, and modulate the flux of evaporated organic materials in a vacuum chamber. We prove the feasibility of evaporative printing of small molecular organic materials at resolutions of the order of 800 dpi with high-throughput on large areas.; (cont.) We demonstrate that MicroElectroMechanical Systems can be used to pattern organic thin films in a way that combines the advantages of ink-jet printing and thermal evaporation. We also present the design and fabrication of a microevaporator for molecular organics...

‣ Indentation of plastically graded materials

Choi, In-Suk, Ph. D. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 126 p.
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The introduction of certain controlled gradients in plastic properties is known to promote resistance to the onset of damage at contact surfaces during some tribological applications. Gradients in composition, microstructure and plastic properties can also be deleterious to contact-damage resistance in some situations. In order to realize such potentially beneficial or deleterious effects of plastic property gradients in tribological applications, it is essential first to develop a comprehensive understanding of the effects of yield strength and strain hardening exponent on frictionless normal indentation. To date, however, systematic studies of plasticity gradient effects on indentation response have not been completed. A comprehensive parametric study of the mechanics of indentation of plastically graded materials is completed in this work by recourse to finite element (FE) computations. On the basis of a large number of detailed computational simulations, a general methodology for assessing instrumented indentation response of plastically graded materials is formulated so that quantitative interpretations of depth-sensing indentation experiments could be performed. The specific case of linear gradient in yield strength is explored in detail.; (cont.) The FE analysis leads to a universal dimensionless function to predict load displacement curves for plastically graded engineering materials. Experimental validation of the analysis is performed by choosing the model system of an electrodeposited nanostructured Ni-W alloy...

‣ Materials and devices for optical switching and modulation of photonic integrated circuits

Seneviratne, Dilan Anuradha
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 129 p.
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The drive towards photonic integrated circuits (PIC) necessitates the development of new devices and materials capable of achieving miniaturization and integration on a CMOS compatible platform. Optical switching: fast modulation and add-drop switches, key components in a PIC, were investigated. A MEMS-based approach was utilized to control switching in planar ring resonator waveguide structures. A switch extinction ratio of 15 dB, switch speed of 60 is and 1 mW operating power were demonstrated. A metal-insulator transition material, V02, was identified as a material with potential for enhancing the switch speed with speeds in excess of gigahertz rates with minimal device footprint. Fundamental material transport properties and nonstoichiometry in VO2 were characterized. Nonstoichiometry as high as 5% was measured. A Frenkel defect model was used to describe the behavior in V02 in which vanadium interstitials were attributed to be the dominant ionic defect in the reducing regime. Frozen-in vanadium interstitials, acting as shallow donors lying 20 meV below the conduction band in the semiconducting phase, enhance the low temperature conductivity and free carrier concentration.; (cont.) VO2 was shown to exhibit an activated mobility in its semiconducting and "metallic" phases with room temperature mobility estimated to be 5x10-2 cm2/Vs. Electrical switch contrasts of as high as -5000 and optical extinction ratios of approximately 16 dB were demonstrated. Free carrier absorption due to shallow donor vanadium interstitials was identified as a dominant absorption mechanism at near-IR wavelengths. Control of the degree of nonstoichiometry was shown to influence the near-IR absorption effects. To address the need for an integrated fast switch for data encoding...

‣ Percolation and homogenization theories for heterogeneous materials

Chen, Ying, Ph. D. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 145 p.
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Most materials produced by Nature and by human beings are heterogeneous. They contain domains of different states, structures, compositions, or material phases. How these different domains are distributed in space, or in other words, how they connect to one another, determines their macroscopic properties to a large degree, making the simple rule-of-mixtures ineffective in most cases. This thesis studies the macroscopic effective diffusion, diffusional creep, and elastic properties of heterogeneous grain boundary networks and composite solids, both theoretically and numerically, and explores the microstructure-property correlations focusing on the effects of microstructural connectivity (topology). We have found that the effects of connectivity can be effectively captured by a percolation threshold, a case-specific volume fraction at which the macroscopic effective property undergoes a critical transition, and a set of critical scaling exponents, which also reflect the universality class that the property belongs to. Using these percolation quantities together with the generalized effective medium theory, we are able to directly predict the effective diffusivity and effective diffusional creep viscosity of heterogeneous grain boundary networks to a fairly accurate degree. Diffusion in composite solids exhibits different percolation threshold and scaling behaviors due to interconnectivity at both edges and corners. Continuum elasticity suffers from this complexity as well...

‣ Synthesis and microfabrication of elastomeric biomaterials for advanced tissue engineering scaffolds

Bettinger, Christopher John, 1981-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 252 leaves
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The subject of this thesis lies at the interface of microfabrication technology and advanced biomaterials synthesis and processing for use in designing and fabricating novel tissue engineered constructs. The unifying theme is to use micron and sub-micron fabrication strategies to form advanced tissue engineering scaffolds which are able to precisely control the microenvironment of cells. These efforts are organized into two thrusts; (1) materials synthesis and process development for microfluidic scaffold fabrication and (2) micro- and nanofabricated synthetic substratum for controlling cell function. In the first thrust, materials-specific processes for the fabrication of poly(glycerol-co-sebacate), a synthetic elastomeric biodegradable polyester, into three-dimensional, hepatocyte-seeded microfluidic constructs is discussed. Material advantages of natural proteins motivated the fabrication of next-generation microfluidic scaffolds using silk fibroin from the Bombyx mori as a bulk material. The need to combine the advantages of both natural proteins and synthetic polyesters motivated the synthesis and characterization of a new class of biodegradable elastomers termed poly(1,3-diamino-2-hydroxypropane-co-polyol sebacate) (APS). APS polymers are tunable and possess the advantages of both natural and synthetic polymers. APS polymers induce a favorable biomaterial-tissue response including reduced fibrous capsule formation and macrophage recruitment compared to PLGA. In vivo degradation half lives could be controlled to between approximately 6 and 100 wks by adjusting polymer composition and processing. The second thrust focuses on the interaction with cells and synthetically fabricated nanotopographic substrates for potential in vascularized tissue engineering applications.; (cont.) The contact guidance response of human embryonic stem cells to poly(dimethylsiloxane) (PDMS) substrates with 600 nm ridge-groove geometry and 600 ± 150 nm feature height was characterized. This motivated the study of endothelial progenitor cell function and morphology on nanofabricated PDMS substrates. Endothelial progenitor cells (EPCs) were found to exhibit increased doubling time from 16.2 ± 0.8 to 20.9 ± 1.9 h for cells grown on flat and nanotopographic substrates...

‣ Assembly of biological building blocks for nano- and micro-fabrication of materials

Chiang, Chung-Yi
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 137 p.
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Experimental studies were performed to fabricate various material structures using genetically engineered M13 bacteriophage. This virus template showed superior controls of material syntheses from nanoscale to microscale. Structures including nanowires, nanoparticle arrays, hetero-particle arrays, and micro-fibers were fabricated using the engineered MI3 virus as the building block and mineralization platform. The mineralization mechanisms were revealed by alternating the types and amounts of peptide motifs displayed on the viral templates. The results showed the importance of a fused peptide motif to mediate the mineralization process of a material, which was dominated by either physical absorption or chemical nucleation. The potential applications of the materials synthesized using the viral template, including energy generation and biosensors, were also demonstrated. For the first time, several types of highly engineered MI 3 virus were used to fabricate nanostructures such as nanowires, nano-arrays, hetero-particle arrays, and complex nanowires. A type 8 phage library was reported to screen peptide motifs for making nanowires. A multi-functionalized viral template, type 8-3 virus, was engineered and demonstrated to create a variety of nano-archietetures. A type 8+8 virus was used to create complex nanowires embedded with different materials. In addition...

‣ Oxide based thermoelectric materials for large scale power generation

Song, Yang, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 69 leaves
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The thermoelectric (TE) devices are based on the Seebeck and Peltier effects, which describe the conversion between temperature gradient and electricity. The effectiveness of the material performance can be described by its figure of merit, ZT, which is defined as ZT = [alpha]²[sigma]T / [kappa] , where a is the Seebeck coefficient of the material, a is the electrical conductivity and [kappa] is the total thermal conductivity, and T is the temperature. In the past, TE power generation has been confined to niche applications. It has been technically and economically more efficient to produce electricity using traditional generators rather than a thermoelectric generator. However, recent significant advances in the scientific understanding of quantum well and nanostructure effects on TE materials properties and modem thin layer and nanoscale manufacturing technologies have combined to create advanced TE materials with high figure of merit (>3). An engineering analysis performed in this study identified large scale waste heat recovery opportunities that are suitable for advanced TE power generation systems.; by Yang Song.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.; Includes bibliographical references (leaves 63-65).

‣ Economic potential of high density data storage implemented by patterned magnetic media technology

Du, Lei, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 65 leaves
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Hard drive industry is facing scaling challenge for areal density to be further increased. This is due to the triangular conflictions among thermal stability (superparamagnetic effect), single-to-noise ratio and writability of the recording media. One of the most promising methods to overcome this constraint is the patterned magnetic media technology. Although it is facing many challenges, the large potential gains in density offered by patterned media make it one of the possible milestones on the horizon for future of the disk drives industry. One of the biggest challenges for patterned media is to realize its mass fabrication provided reduced cost per bit. The basic fabrication approach is to use lithography to pattern the magnetic materials on the platter. However, patterned media requires well-ordered nanoarrays with dimensions less than 25 nm, which challenges the state-of-art lithography technologies. This M. Eng. project focuses on evaluations of the technologies and fabrication schemes potential for patterned media from various aspects like technical barriers, cost and intellectual properties. Technologies including E-beam lithography, nanoimprint lithography, templated diblock copolymer self-assembly and self-assembled magnetic nanoparticles are discussed. Cost modeling was done to prove the enormous gain in revenue for the proposed fabrication scheme. It is proposed that the fabrication scheme of templated diblock copolymer for making the master stamp for nanoimprint followed by nanoimprint lithography for mass production has the largest potential for patterned media. However...

‣ Orthopaedic applications of ferromagnetic shape memory alloys; Orthopedic applications of ferromagnetic shape memory alloys

Guo, Weimin, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 40 leaves
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Ferromagnetic shape memory alloys (FSMAs) are a new class of magnetic field-actuated active materials with no current commercial applications. By applying a magnetic field of around 0.4 T, they can exert a stress of approximately 1.5 MPa, exhibiting a strain of up to 6%. This thesis evaluates their technical and commercial feasibility in orthopaedic applications. Remote actuation is a key advantage FSMAs have over current implant materials. Also, the human body temperature is constant, providing a stable environment for FSMAs to operate. A number of potential orthopaedic applications are proposed and evaluated. Out of these, the most prominent application is the spinal traction device. It is a temporary implantable device, intended to perform internal spinal traction. A design has been proposed, with suggestions of suitable materials for its various components and appropriate device dimensions. Preliminary market and cost analyses have been conducted. This orthopaedic technology is currently in its infant stage. To commercialize this device, more trials are needed.; by Weimin Guo.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.; Includes bibliographical references (leaves 36-40).

‣ An evaluation of indium antimonide quantum well transistor technology; Evaluation of InSb quantum well transistor technology

Liu, Jingwei, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 102 leaves
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Motivated by the super high electron mobility of Indium Antimonide (InSb), researchers have seen great potential to use this new material in high switching speed and low power transistors. In Dec, 2005, Intel and its partner, QinetiQ, Ltd, announced 85nm gate length enhancement and depletion mode InSb quantum well transistors. Such transistors can operate as high as 305GHz and power consumption is reduced by a factor of 10. In this thesis, the emerging InSb transistor technology is discussed in details. Given its superior performance, it may complement silicon transistor to extend Moore's law in the next decade. The prospect of InSb transistor is also compared with other nanotechnology transistors, such as carbon nanotube and silicon nanowire. Several potential markets are figured out, namely, microprocessor, low noise amplifier and millimeter wave device. Related patents are evaluated. It is found that most of the patents are held by Intel's partner, QinetiQ Ltd. and thus patents issue would not block the launch of products. A joint venture or strategy alliance model is proposed to reduce the risk of investment. In addition, a cost model is presented at the end. It is concluded that cheap silicon substrate and large enough production scale are two crucial factors for the commercialization success of InSb transistor technology.; by Jingwei Liu.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ Technological assessment and evaluation of high power batteries and their commercial values

Teo, Seh Kiat
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 112 p.
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Lithium Ion (Li-ion) battery technology has the potential to compete with the more matured Nickel Metal Hydride (NiMH) battery technology in the Hybrid Electric Vehicle (HEV) energy storage market as it has higher specific energy and energy. However, in order to improve Li-ion battery technology to fulfill the' HEV energy storage requirements, a very high specific power characteristic is needed to boost its commercial attractiveness. The high specific power characteristic will in turn lead to better a vehicle performances, reduced fuel consumption and emissions. In this thesis, we quantify the fuel savings benefits from HEV, and the marginal value of each W/kg improvement in this battery technology. From the analysis, we conclude that the marginal value of regenerative braking, acceleration, social cost and fuel economy are $13.83, $22.64, $0.9959 and 0.0987 MPG per W/kg per each HEV lifespan respectively. Besides, a variety of start-up companies in various stages of commercialization of these technologies as well as the related intellectual property strategies are also discussed. Finally, suggestion of potential business strategies for licensing and commercializing Li-ion battery technology with respect to HEV energy storage market is presented.; by Seh Kiat Teo.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ Phase transformations and microstructural design of lithiated metal anodes for lithium-ion rechargeable batteries

Limthongkul, Pimpa, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 166 p.; 11970072 bytes; 11969828 bytes; application/pdf; application/pdf
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There has been great recent interest in lithium storage at the anode of Li-ion rechargeable battery by alloying with metals such as Al, Sn, and Sb, or metalloids such as Si, as an alternative to the intercalation of graphite. This is due to the intrinsically high gravimetric and volumetric energy densities of this type of anodes (can be over an order of magnitude of that of graphite). However, the Achilles' heel of these Li-Me alloys has been the poor cyclability, attributed to mechanical failure resulting from the large volume changes accompanying alloying. Me-oxides, explored as candidates for anode materials because of their higher cyclability relative to pure Me, suffer from the problem of first cycle irreversibility. In both these types of systems, much experimental and empirical data have been provided in the literature on a largely comparative basis (i.e. investigations comparing the anode behavior of some new material with older candidates). It is the belief of the author that, in order to successfully proceed with the development of better anode materials, and the subsequent design and production of batteries with better intrinsic energy densities, a fundamental understanding of the relationship between the science and engineering of anode materials must be achieved...