Página 8 dos resultados de 2573 itens digitais encontrados em 0.174 segundos

‣ Coarse-graining and data mining approaches to the prediction of structures and their dynamics

Curtarolo, Stefano, 1969-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 263 p.; 2678485 bytes; 2683753 bytes; application/pdf; application/pdf
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Predicting macroscopic properties of materials starting from an atomistic or electronic level description can be a formidable task due to the many orders of magnitude in length and time scales that need to be spanned. A characteristic of successful approaches to this problem is the systematic coarse-graining of less relevant degrees of freedom in order to obtain Hamiltonians that span larger length and time scale. Attempts to do this in the static regime (i.e. zero temperature) have already been developed, as well as thermodynamical models where all the internal degrees of freedom are removed. In this thesis, we present an approach that leads to a dynamics for thermodynamic-coarse-grained models. This allows us to obtain temperature-dependent and transport properties. The renormalization group theory is used to create new local potential models between nodes, within the approximation of local thermodynamical equilibrium. Assuming that these potentials give an averaged description of node dynamics, we calculate thermal and mechanical properties. If this method can be sufficiently generalized it may form the basis of a Multiscale Molecular Dynamics method with time and spatial coarse-graining. In the second part of the thesis, we analyze the problem of crystal structure prediction...

‣ Characterization and device applications of II-VI nanocomposites

Heine, Jason Randall, 1972-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 121 p.; 8392211 bytes; 8391966 bytes; application/pdf; application/pdf
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This thesis describes the synthesis and characterization of CdSe core - ZnS shell (CdSe)ZnS nanocrystals, which behave as quantum dots (QDs), their incorporation into transparent polymers and ZnS, and possible device applications of the resulting luminescent materials. The crystalline structure of these quantum dots is examined using XRD. The nature of the core-shell interface is inferred by comparison of the XRD spectra with calculated spectra and in consideration of TEM images of the QDs. The influence the addition of a shell material over the CdSe core has on the QD exciton energy is examined by comparing the measured and calculated change in band edge emission energy when ZnS or CdS are used as overcoat materials. Methods of incorporating the QDs into various polymers are considered and the emission of a GaN LED/ QD-containing polymer composite structure is simulated and compared with the output of actual devices. The simulation is also used as a design tool in the production of a white-light LED. Embedding the QDs into ZnS films via an electrospray technique is carried out and the resulting films characterized with x-ray diffraction and photoluminesence measurements. QD film / ZnS film structures are also considered, with atomic layer deposition used as the method for depositing the ZnS to improve the film uniformity as well as to maintain high quality deposition at temperatures low enough to be compatible with the presence of QDs. Finally...

‣ Next generation optical receivers : integration and new materials platform

Zhang, Yiwen, 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 81 leaves; 4643551 bytes; 4652424 bytes; application/pdf; application/pdf
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Future growth of optical communication into new application and market space is highly dependent on the ability of optical receivers to increase functionality while reducing price and physical size. Current hybrid receiver technology is inadequate in meeting the cost and performance demands of future market. Monolithic integration and new material systems are potential solutions and have been the focus of research investigation. This thesis summarizes the research progress of monolithic integration on InP, and the achievements in realizing 1.55[micro]m photodetector on GaAs and Si and their potentials for monolithic opto-electronic integrated circuits. The overall trend for next generation receivers is to move towards higher levels of integration, with investigation in new material systems that have the potentials for lower cost and larger scale integration. The impact of monolithic integration optical receiver components is analyzed in a cost analysis model.; by Yiwen Zhang.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2004.; Includes bibliographical references (leaves 77-81).

‣ Commercial applications of nanostructures created with ordered porous alumina

Wells, Brendan Christopher, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 87, [1] leaves; 5686970 bytes; 5696780 bytes; application/pdf; application/pdf
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In the drive from microfabrication to nanofabrication, porous alumina templates may play a key role in technological evolution. Under the right processing conditions, ordered pores can grow in anodic aluminum oxide, which is a high strength, thermally and electrically insulating material. There are many potential applications for porous alumina templates, ranging from the simple fabrication of nanostructure arrays to the more complex processing of components for end-user products such as nano-integrated circuits and gas sensors. Porous alumina templates can also be processed to have long-range pore ordering on an entire twelve-inch silicon wafer, which may be of unique benefit to processes requiring such pore precision, such as parallel electron beam lithography. The high aspect ratios which can be attained through porous alumina template technology may also offer unique advantages in applications such as field-emission-based devices. As a durable high strength material, porous alumina templates are not limited by extreme process conditions, further extending the reach of their application. The vast array of applications allows the technology to be financially attractive inside business models ranging from sustaining to disruptive innovation. Porous alumina template technology has the necessary multitude and diversity of attributes to play a crucial role in the future of nanotechnology.; by Brendan Christopher Wells.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ Self-healing properties of water filtration membranes containing amphiphilic comb polymer

Devereaux, Caitlin Albright, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 120 p.; 7511014 bytes; 7525820 bytes; application/pdf; application/pdf
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(cont.) and filtration experiments, as well as other characterization techniques. Surface analysis is accomplished via x-ray photoelectron spectroscopy (XPS). Membrane samples are cleaned (in hydrogen peroxide or chromic-sulfuric acid (Chromerge)) and/or annealed (in 90⁰C deionized water), and their elemental surface composition and specific carbon binding environments are determined by XPS. Filtration experiments are done by alternating feed solutions of deionized water and a foulant (either bovine serum albumin or an oil/water emulsion). The flux of the feed solution is measured before fouling, during fouling, and after fouling, to determine the extent of fouling recovery. Also, the compositions of the permeates are analyzed via ultraviolet-visible spectroscopy to determine the rejection coefficient of the membrane. The data presented in this thesis show that PVDF blend membranes containing P(MMA-r-POEM) are capable of generating a fresh surface layer of PEO multiple times, even after extended cleaning sessions using concentrated acid. Membranes of varying thickness are shown to exhibit PEO-regenerative abilities, but it appears that thick membranes have better fouling recovery than thinner, filtration-series membranes. Also, it is found that a blend membrane stripped of all of its surface PEO (by a 24-hour-long exposure to Chromerge) is able to restore PEO to its surface with roughly 24 hours of annealing ...; Freshwater shortages are a tremendous problem for certain areas of the world...

‣ Engineered substrates for coplanar integration of lattice-mismatched semiconductors with silicon

Pitera, Arthur Joseph, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 208 p.; 14272761 bytes; 14299374 bytes; application/pdf; application/pdf
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As we approach the end of traditional CMOS scaling, further improvements in integrated circuit performance and functionality will become limited by the inherently low carrier mobility and indirect bandgap of silicon. These performance shortcomings can be supplemented with high performance semiconductors such as Ge and GaAs, which have respectively improved carrier mobilities and a direct bandgap for efficient light emission. However, due to the economic superiority of Si-based microelectronics, it is unlikely that the CMOS industry will abandon Si entirely. Instead, it will be necessary to integrate materials such as Ge and GaAs with the Si platform by means of engineered substrates. In this thesis, thin Ge layers were transferred to Si by wafer bonding of compositionally graded structures. This approach combines the beneficial aspects of graded buffers with those of wafer bonding to provide a coplanar integration platform for lattice-mismatched semiconductors. The various innovations that were necessary to realize epitaxial layer transfer from virtual substrates stem from the fact that thin films of Ge are difficult to planarize. The large surface roughness of graded buffers requires smoothing of the surface prior to bonding. The poor surface passivation of GeO2 in aqueous chemo-mechanical planarization (CMP) slurries necessitates that Ge virtual substrates be planarized indirectly...

‣ Fabrication of complex oral drug delivery forms by Three Dimensional Printing (tm)

Katstra, Wendy E. (Wendy Ellen), 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 241 p.; 11383884 bytes; 11399966 bytes; application/pdf; application/pdf
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Three Dimensional Printing 3DPTM is a novel solid freeform fabrication technology that has been applied to the fabrication of complex pharmaceutical drug devices. Limitations of the technology as relating to pharmaceuticals have been addressed and prototype dosage forms have been fabricated. The resolution of the 3DP tablets was found to depend on particle size and liquid migration during printing and drying. The surface finish of 3DP tablets was enhanced by uniaxial pressing. Migration inhibiting additives were effective in limiting transport. Both aqueous and ethanol-based solutions showed a decrease in migration on the order of 20% when appropriate powder bed additives were introduced. Migration was also decreased by pre-printing barriers to confine secondary printed drug solutions. Low dosage forms were fabricated with as little as 2.3 nanograms. Lower dosages are expected upon dilution of the initial drug solution. Printing forms with high dosage is limited by powder void volume, filling efficiency, and drug solubility limits. Multiple print passes increased the dosage per tablet volume, 6, at the expense of process time. The use of drug suspensions to overcome solubility limits and uniaxial compression to reduce tablet volume was shown to significantly increase 6. The highest 8 achieved was 427 mg/cc for pressed suspension-printed tablets...

‣ An evaluation of grain boundary engineering technology and processing scale-up

Zelinski, Jeffrey A
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 74 p.; 4340616 bytes; 4343633 bytes; application/pdf; application/pdf
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Grain boundary engineering is the manipulation of low stacking-fault energy, face- centered cubic material microstructures to break the connectivity of the general grain boundary network through the addition of special grain boundaries. Grain boundary engineering processing consists of thermomechanical cycling, i.e. repeated strain and annealing sequences and provides a method of producing more robust polycrystalline materials. This evaluation presents an introduction to the fundamental principles of grain boundary engineering, reviews the processing techniques and relevant intellectual property, analyzes the processing variables and their effect on a manufacturing line, surveys the current market and competition, and provides a preliminary cost analysis.; by Jeffrey A. Zelinski.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.; Includes bibliographical references (p. 50-52).

‣ Evaluation of the economic feasibility of core-shell baroplastic polymers and a comparison to traditional thermoplastic elastomers

Ibrahim, Sarah H
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 70 leaves; 3001259 bytes; 3004112 bytes; application/pdf; application/pdf
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Baroplastic materials are pressure miscible systems that can be molded by the application of pressure at low/room temperature. They have the potential to replace traditional thermoplastic elastomers in many applications. To quantitatively determine the competitiveness of baroplastic materials in current markets, a detailed cost model was developed. Embedded in the cost model is a polymer flow model that predicts processing times as a function of processing pressure. The raw material cost of baroplastics was roughly estimated to input into the cost model. The results of the cost model show that baroplastics have a significant economic advantage over thermoplastic elastomers due, mostly, to the greatly reduced cycle times associated with processing baroplastic materials. Recommendations for future work include developing a more refined estimate of the raw material price of baroplastics as well as investigating the costs of more specific applications.; by Sarah H. Ibrahim.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005.; Includes bibliographical references (leaf 39).

‣ Electrode materials for the electrolysis of metal oxides

Cooper, Benjamin D
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 36 leaves; 1687097 bytes; 1686436 bytes; application/pdf; application/pdf
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Carbon, tungsten, platinum, and iridium were examined as candidate anode materials for an electrolytic cell. The materials were pre-selected to endure high process temperatures and were characterized for inertness and high current density during electrolysis using voltammometric techniques. Inertness is viewable through current discrepancies dependent on voltage scan direction at low voltage, consumption of current by metal oxide formation, and ease of surface oxide electro-stripping. Conductivity during electrolytic oxidation is observable as current density maximization at high voltages. While carbon, tungsten, and platinum formed surface oxides, iridium remained quite inert. In addition, the voltage hold-time was found to affect the leading current density, as platinum performed best during cyclic voltammometry, but iridium performed best during potentiostatic electrolysis. The intermediate potentiodynamic scan-rate displays the transition from platinum to iridium dominated current density.; by Benjamin D. Cooper.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, June 2006.; "May 2006."; Includes bibliographical references (leaves 35-36).

‣ Numerical modeling of interface dynamics and transport phenomena in transport-limited electrolysis processes

Pongsaksawad, Wanida
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 117 p.
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Electrochemical reactions in materials and processes induce morphological instability on the cathode, which can lead to porous deposits or system failure. The growth of the protrusion is a complex phenomenon which involves chemical, electrical, and momentum driving forces in the system. Thus, it is important to understand the effect of electrochemistry in phase boundary evolution in order to optimize the performance of such processes. This thesis contributes to predicting and controlling such interface instability phenomena by developing a computational model that captures them. Successful application of the model to emerging metal extraction processes demonstrates its usefulness. A phase field model of electrochemical interface is developed for transport-limited electrolysis with rapid charge redistribution. This new Cahn-Hillard phase field formulation includes a model electrostatic free energy term, which captures the behavior of the diffuse interface under the applied electric field, in addition to transport by free energy gradient and convection. The model agrees with published stability criterion for a solid cathode. When the electrodes and electrolyte are low-viscosity fluids, flow stabilizes the interface.; (cont.) A new stability criterion for metal reduction in a liquid-liquid system is derived and agrees well with the model results. Next...

‣ Technical and economic feasibility of a high-temperature self-assembling battery

Bradwell, David (David Johnathon)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 136 p.
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A conceptual high-temperature battery system for large-scale grid power applications was proposed, described, and evaluated. Unlike conventional battery technologies whose maximum current rate is constrained by at least one solid phase, the novel three-layer liquid-phase electrode-electrolyte-electrode cell facilitates high diffusivity and facile interfacial kinetics, which results in rapid ion transport and low activation overpotential. In addition to the extremely high currents enabled by the absence of solid-liquid interfaces, this cell configuration represents a robust design that can be easily manufactured. The molten components will self assemble due to their immiscibility and different densities. Another key feature is that a molten metalloid acts as the positive electrode, while an alkali or alkaline earth metal acts as the negative electrode, providing two electronically conductive molten electrodes. The cell is estimated to have a lifespan of 10-15 years with >3,000 deep-discharge cycles, to require minimal maintenance, and to supply 1-5 A/cm2 at 0.9 V with 80% DC-DC cycle-efficiency.; (cont.) One embodiment comprising electrodes of magnesium (negative) and antimony (positive) and a molten sulfide supporting electrolyte served as the basis for a detailed feasibility assessment (alternative electrode and electrolyte materials were also discussed). A cost model was created based on an entire battery system...

‣ Potential commercial application of a bi-layer bone-ligament regeneration scaffold to anterior cruciate ligament replacement

Li, Jessica C. (Jessica Ching-Yi)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 94 p.
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A business model was created in order to explore the commercial application of a bi-layer bone-ligament scaffold to the treatment of torn anterior cruciate ligaments (ACL) requiring replacement. The two main keys in producing the bone scaffold are triple co-precipitation of type-I collagen, chodroitin-6-sulphate, and calcium phosphate minerals and the use of lyophilization to create a network where all the materials are homogeneously dispersed and present in significant amounts. This process allows the creation of a porous network whose physical characteristics, mechanical properties, and material content can all be changed to create a scaffold that closely mimics natural bone. A collagen and chondroitin-6-sulphate scaffold is used for ligament regeneration. The ACL replacement market was chosen because it is one of the most commonly surgically repaired ligaments in the body and because all of the current treatments have drawbacks.; (cont.) The exercise of creating a business model made it clear that the commercial potential of starting a company that focused on marketing a direct ACL replacement scaffold would most likely not be successful mainly because surgeons would hesitate to use this product over current methods that are satisfactory and it would be difficult to separate our product from other newer methods which all boast similar advantages over current treatment options. However...

‣ Commercialization potential of compositionally graded Ge - Si₁₋x̳Gex̳ - Si substrates for solar applications

Goh, Johnathan Jian Ming
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 103 leaves
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This project considers the potential of Ge - Si₁₋x̳Gex̳ - Si substrates for solar applications. The use of compositionally graded substrates to achieve heterointegration across different materials platforms such as Si, Ge and GaAs has proven successful and dual junction solar cells have been fabricated on such substrates. The potential for graded substrates in the solar market is discussed considering the current technology, market players and worldwide renewable energy policies. A cost model is also developed and analyzed in the course of writing to assess the feasibility of this commercial enterprise. The result of these analyses highlights the technical and commercial viability of graded substrates in the solar market.; by Johnathan Jian Ming Goh.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.; In title on t.p., double-underscored "x" appears as subscript.; Includes bibliographical references.

‣ Cr-Ga-N materials for negative electrodes in Li rechargeable batteries : structure, synthesis and electrochemical performance

Kim, Miso
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 97 p.
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Electrochemical performances of two ternary compounds (Cr2GaN and Cr3GaN) in the Cr-Ga-N system as possible future anode materials for lithium rechargeable batteries were studied. Motivation for this study was dealt in chapter 2 following chapter 1 that covered introduction to batteries, lithium ion batteries and anode materials for lithium ion batteries. Synthesis method with less time was attempted and factors affecting synthesis of these compounds were investigated. (Chapter 3) Through electrochemical characterization and insitu XRD, practical values of electrochemical capacities were examined in comparison with theoretical capacity values (Chapter 4) and also possible reaction mechanisms of these compounds vs. Li were proposed (Chapter 5).; by Miso Kim.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.; Includes bibliographical references (p. 95-97).

‣ Multiscale structural and mechanical design of mineralized biocomposites

Bruet, Benjamin J. F. (Benjamin Jean Fernand), 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 222 p
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Gastropod mollusk nacre tablets and Polypterus senegalus armored scales share common features such as a very complex and changing structure spanning several length scales. The smallest building blocks are single crystals, have dimensions of a from tens of nanometers to several microns and are intimately blended with an organic glue present within pores or between the crystallites. In particular, our results strongly suggest that nacre tablets possess nanoscale porosity in the form of elongated tubules that may contain the intratablet macromolecules. Their unique structure allows these materials deform in a ductile way at the nanoscale, with no cracks observed, and to confine deformation at the microscale so as to impede crack propagation. Gradient in the mechanical properties are ubiquitous at both the microscale (scales) and the nanoscale (nacre tablets), preventing stress concentration and enhancing strain distribution. The armored scales thus exhibit a unique spatial functional form of mechanical properties with regions of differing levels of gradation within and between material layers, as well as layer with an undetectable gradation. Though highly mineralized, these biomaterials also exhibit greater local heterogeneity in their mechanical properties compared to pure minerals. Materials layers have distinct morphology and mechanical properties depending on their role (resistance to abrasion for harder outer layers...

‣ Morphology and self-assembly behavior of side chain liquid crystalline block copolymers

Verploegen, Eric Anton
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 237 leaves
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There is significant interest from both the academic and industrial communities for understanding and controlling the self-assembly behavior of complex macromolecular systems and has been an active area of research in recent years. Such systems can be designed to result in a wide range of nanoscale morphologies and greater functionality can be introduced with increasing complexity.This thesis focuses on the synthesis and characterization of a class of side chain liquid crystalline block copolymers (SCLCBCPs) that are based on a low glass transition temperature (Tg) siloxane backbone. Moieties that self-assemble into smectic liquid crystalline (LC) phases are covalently attached to the polystyrene-polyvinylmethylsiloxane (PS-PVMS) block copolymer backbone. Precise control over the functionalization of the LCs onto the functional siloxane backbone allows for unique control over the self-assembly and the resulting properties of the system. The LC content significantly affects the stability of the smectic mesophase and subsequently the interactions with the inter-material dividing surface (IMDS) with the PS domains. A strong preference for homogenous anchoring of the LC moieties relative to the IMDS is observed, and increasing the LC content intensifies the preference for this arrangement. Utilizing the effects of LC anchoring to alter the self-assembly behavior is a reoccurring theme throughout this work. Additionally...

‣ Technological assessment of silicon on lattice engineered substrate (SOLES) for optical applications

Leung, Man Yin
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 79 leaves
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Over the past decade, much effort had been placed to integrate optoelectronic and electronic devices. Silicon on lattice engineered substrate (SOLES) had been developed for such purpose. As SOLES technology mature, a technological analysis is important so as to evaluate its potentials. In this report, a technological assessment will be done on the SOLES technology. This technology will be evaluated technologically and economically. The IP landscape in which SOLES would be applied is also looked into so as to ensure that there would be no infringement of intellectual properties. It has been concluded in this report that LED printer market would be a good introduction application for SOLES. A fabless company model is suggested as the start-up approach. A simple cost model had been done in this report. Cost of fabrication is expected to be reduced by 13% by changing current fabrication process to SOLES process. On the final note, if SOLES could capture a market share in the world market of 0.1% to 1% , the expected profit was projected to be about USD$1.32 M over the next five years, with an expected sales of about 210 thousand unit, averaging about USD$264K per annum.; by Man Yin Leung.; Thesis (M. Eng.)--Massachusetts Institute of Technology...

‣ Combinatorial lipid-like materials for intracellular delivery of small RNAs that activate innate antiviral immune responses and adjuvant vaccines

Nguyen, David-Huy Nhu
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 200 leaves
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RNA-based therapy is an exciting new realm of experimental medicine due to the diverse roles of RNA in the human body. RNA function depends on sequence, structure, and cellular location. Whereas cytosolic short-interfering RNA (siRNA) can be used to turn off genes through RNA interference (RNAi), it was observed that the same siRNA can also activate an innate immune response. Recognition of RNA by specialized immune cells occurs through pattern recognition receptors, which have evolved to respond to RNA viruses, such as the Toll-like receptors (TLR) 7 and 8 located in the endosome of dendritic cells. Tailoring the multiple functions of RNA for a desired clinical application will require novel systems for intracellular delivery. A library of structurally-related cationic lipid-like materials, termed "lipidoids", was developed to facilitate uptake of small RNAs, and the role of drug delivery in controlling RNA function was investigated. In an experimental animal model of RNA interference of influenza virus, treatment with a lipidoid-siRNA nanoparticle efficiently activated a type I interferon response in a sequence-dependent manner suppressing lung viral titer over 97%. Specific chemical modifications to the siRNA prevented TLR7/8 engagement and also prevented antiviral responses...

‣ Technology assessment and market analysis of solid state ultracapacitors

Jiang, Zibo
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 98 p.
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This report provides quantitative analysis of Solid State Ultracapacitors (SSUs) from technological and financial perspectives. SSUs are Ultracapacitors with solid electrolytes predicted to have huge application potential as the electrical energy storage device in Hybrid Electrical Vehicles (HEVs) due to the projected high energy density. The potential high energy density of SSUs is achieved through engineering dielectric materials to possess high breakdown voltage and/or DC permittivity. Among the available SSU models, Electrical Energy Storage Units (EESUs) have been reported to possess energy density as high as 280 Wh/kg with the permittivity and breakdown voltage enhancements achieved through engineering composition modified barium titanate powders. Organic Solid State Ultracapacitors (OSSUs) is a proposed concept of SSUs with conductive particle filled polymer systems as the dielectric material to take advantage of the systems' giant permittivity phenomenon reported under AC. However, through experiments and modeling, such giant permittivity is not found under DC and it is thought that the reported AC giant permittivity may be strongly distorted by the eddy current loss in the commonly used equivalent circuit characterization model and therefore does not contribute to the energy density enhancement. It is also found that the geometric dispersion of conductive particles does not contribute to the energy storage capability. Hence...