Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005. / Includes bibliographical references (leaves 86-88). / Porous collagen-glycosaminoglycan (CG) scaffolds have been studied extensively and proven to be capable of tissue regeneration in vivo for applications including skin regeneration templates, hollow nerve guides and conjunctiva regeneration. While the current CG scaffold has been thoroughly examined both mechanically and clinically, it has yet to prove appropriate for load- bearing applications. This study will investigate the mechanical properties of a mineralized CG scaffold and its application potential in a load-bearing environment. Through the introduction of calcium-phosphate mineral into the standard CG formulation the matrix analog will be available for bone regeneration. Utilizing a patented triple co-precipitation technique developed at Massachusetts Institute of Technology and Cambridge University, a homogeneous mineralized scaffold will be manufactured. Comparison to healthy trabecular bone as well as the selection of the most appropriate extracellular matrix analog will be presented. The key to commercial success is the introduction of a bi-layer bone and cartilage regeneration template to address concerns and difficulties in cartilage repair today. This dual combination is termed a layered osteochondral scaffold. / (cont.) The commercial viability of this product as well as the company founded on its inception, OrthoCaP, Inc., is delivered as a start-up venture over the next eight to ten years. With several key patents already filed, an extensive patent search was completed to establish leading competitors and technology in the marketplace. Although still in the primary phases of development, short-term profitability can be seen through licensing the technology to larger more secure firms. Long-term profitability is realized through a more scientific approach of broadening the technology to other areas of tissue regeneration and modifying the mechanical and material characteristics associated with collagen based templates. / by Cassandra Holzgartner Ott. / M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005. / Includes bibliographical references (leaves 74-76). / Limitations of electrical wires result in distortion and dispersion of the signal for long distances. That have emerged optical communication as the only way of communication for long distances. For medium distances optics can support the high data rates required by the latest applications. Optical networks are becoming the dominant transmission medium as the data rate required by different applications increases. The bottleneck for implementing optical instead of electric networks for medium distances, like local area network, is the cost of the optical components and the cost of replacing the existing copper network. This thesis will discuss the possible cost benefits that come from the use of different materials like plastic optical fiber instead of silica fiber or Si, Si/Ge instead of InP or GaAs for the transceiver as well as the trade offs between the performance and cost when discrete transceiver is replaced by the monolithically integrated transceiver, by using a process based cost model. / by Genta (Meco) Gusho. / M.Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1988. / On t.p. all "x̳" is subscript. / Includes bibliographical references. / Kimberley Elcess. / Ph.D.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 72-83). / In the last decade, the field of single cell mechanics has emerged with the development of high resolution experimental and computational methods, providing significant amount of information about individual cells instead of the averaged characteristics provided by classical assays from large populations of cells. These single cell mechanical properties correlate closely with the intracellular organelle arrangement and organization, which are determined by load bearing cytoskeleton network comprised of biommolecules. This thesis will assess the feasibility of a high throughput single cell force spectroscopy using an atomic force microscopy (AFM)-based platform. A conventional AFM set-up employs a single cantilever probe for force measurement by using laser to detect the deflection of the cantilever structure, and usually can only handle one cell at a time. To improve the throughput of the device, a modified scheme to make use of cantilever based array is proposed and studied in this project. In addition, to complement the use of AFM array, a novel cell chip design is also presented for the fine positioning of cells in coordination with AFM cantilevers. The advantages and challenges of the system are analyzed too. To assess the feasibility of developing this technology, the commercialization possibility is discussed with intellectual property research, market analysis, cost modeling and supply chain positioning. Conclusion about this technology and its market prospect is drawn at the end of the thesis. / by He Cheng. / M.Eng.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 34). / Bamboo has received much interest recently as a construction material due to its strength, rapid growth, and abundance in developing nations such as China, India, and Brazil. The main obstacle to the widespread use of bamboo as a structural material is the lack of adequate information on the mechanical properties of bamboo. In this work, the microstructure and mechanical properties of Phyllostachis dulcis bamboo are studied to help produce a model for the mechanical properties of bamboo. Specifically, a linear relationship is established between the density of bamboo samples, which is known to vary radially, and their strength in compression. Nanoindentation of vascular bundles in various positions in bamboo samples revealed that the Young's modulus and hardness of the bundles vary in the radial direction but not around the circumference. The compressive strength of bamboo samples was found to vary from 40 to 95 MPa, while nanoindentation results show the Young's modulus of vascular bundles ranges from 15 to 18 GPa and the hardness ranges from 380 to 530 MPa. / by Michael R. Gerhardt. / S.B.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 52-56). / Bulk luminescent solar concentrators (LSC) cannot make use of Forster resonance energy transfer (FRET) due to necessarily low dye concentrations. In this thesis, we attempt to present a poly-vinylalcohol (PVA) waveguide containing dye-aggregate polystyrene nanospheres that enable FRET at concentrations below that required for the bulk LSC due to dye confinement. In the aqueous state, the maximum achieved energy transfer efficiency of the dye-doped nanoparticles was found to be 8 7% for lwt%/lwt% doping of Coumarin 1 (C1) and Coumarin 6 (C6). In the solid state, however, energy transfer is lost, reducing to 32.8% and 20.1% respectively for the C1(lwt%)/C6(lwt%) and C1(0.5wt%)/C6(lwt/ ) iterations, respectively. Presumably, the dyes leach out of the polystyrene nanospheres and into the PVA waveguide upon water evaporation during drop casting. / by Ron Rosenberg. / S.B.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008. / Includes bibliographical references (p. 45-48). / There has been much hype in the research and development of continuous glucose monitoring technologies, driven by the enormous and rapidly expanding glucose monitoring market and the large and growing base of diabetes patients. Continuous glucose monitoring has shown significant benefits over traditional intermittent blood glucose testing in reducing the risks of developing long-term complications associated with diabetes, by maintaining blood glucose concentrations to near-normoglycemic levels and reducing glycemic variability. In this thesis, commercially available continuous glucose monitoring systems as well as those still in development are evaluated. SWOT analysis shows that continuous glucose monitoring has a promising future, but there remain a number of challenges to be overcome, such as accuracy, sensor span, data handling, cost and reimbursement issues. It is concluded that continuous glucose monitoring will be the roadmap for future diabetes management. Ongoing technological advances in continuous glucose monitoring systems will hopefully close the loop for a fully automated artificial pancreas and develop a cure for Type I diabetes. / by Guang Li. / M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008. / Includes bibliographical references (leaves 75-80). / Thermal and magnetically sensitive polymers are a new class of materials with unique properties suitable for applications in drug delivery. Specifically, these polymers can be combined with a drug reservoir to make a drug delivery device that can be triggered externally. Such a device could be implanted subcutaneously and allow for temporal control of drug release and localized delivery. Current experiments have shown that a prototype device is capable of delivering both small and large molecule drugs. Attractive medical applications for this technology were discovered and their respective markets examined. Additionally, the scientific literature and intellectual property in this field were analyzed for competing technologies that would hinder development of this invention. Novel attributes of this technology were also identified and specific competitive advantages made evident. To facilitate the commercialization of this novel technology, a business model has been proposed that identifies possible risks and provides strategies for overcoming them. Using this model, a timeline for future research and development has been constructed that traces the technology from its current state to a final product that can be launched commercially. The requirements for regulatory approval have also been investigated and a plausible manufacturing process has been established. Furthermore, a cost model and pricing analysis has been conducted to determine if a viable business proposition around this technology can be made. / by Jonathan M. Edward. / M.Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Growth of polycrystalline films involves poorly understood kinetic processes that occur far from equilibrium and lead to complex co-evolution of the surface, microstructure and intrinsic stress of the films. Here we present a comprehensive study consisting of in situ stress measurements, microstructure characterization, and analytical modeling for various polycrystalline systems. We find that in systems of high atomic mobility, the stress change after polycrystalline film growth can be attributed to a fast reversible surface process and a slow irreversible bulk process. The fast process is weakly dependent on temperature and is associated with changes in the shape of grain surfaces. The slow process is strongly dependent on temperature and is mostly associated with grain growth in the bulk of the film. We also discovered a turnaround phenomenon in which, under conditions of intermediate atomic mobility, the stress evolves from a tensile toward a compressive state, and then turns around to evolve toward a tensile state. This stress turnaround phenomenon is strongly dependent on the substrate temperature and deposition rate, and can be attributed to an increase of the grain size during film deposition. Grain growth during deposition not only leads to a tensile component of the intrinsic stress, but also changes the grain size dependence of the compressive component. The compressive component results from incorporation of excess adatoms in grain boundaries, and the magnitude of the compressive stress is controlled by a competition between adatom incorporation in 2D islands and incorporation at grain boundaries. We also investigated the effect of the angle of incidence of the flux of depositing atoms on stress and structure evolution during polycrystalline film growth. We find that as the angle of incidence increases, the coalescence thickness increases and the stress becomes less compressive or more tensile. We attribute these phenomena to the enhanced surface roughness, the shadowing effect, the steering effect and the presence of Ehrlich-Schwoebel barriers during oblique angle deposition. All these effects lead to suppression of the adatom-grain boundary incorporation process. Based on this thesis work, intrinsic stresses in polycrystalline films can be categorized into three types: Type I, the intermediate type and Type II. These behaviors are observed in systems of low, intermediate and high atomic mobility, respectively. Compressive stresses develop in Type II behavior and tensile stresses develop in Type I behavior. The transition of the stress behavior from Type I, to the intermediate type and to Type II is continuous and can be achieved by adjusting deposition conditions. Whether the post-coalescence stress is tensile, or compressive, or evolving from compressive to tensile depends on the homologous temperature, the deposition rate and the angle of the incidence of the flux of depositing atoms. / by Hang Yu. / Ph.D.

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 34-36). / An atomistic approach to modeling the sintering of nanocrystalline alloys has been developed. It has been shown that there exist alloys that exhibit both nanostructured stability and undergo an accelerated sintering process [1], [2]. However, the widespread adoption of such alloys has been limited by a lack of understanding of the processing kinetics that lead to the accelerated sintering phenomena. To better understand the role of surface diffusion, and the effect that system enthalpies of mixing have on inter-particle neck formation, a 3D kinetic monte carlo (KMC) model was proposed to study these phenomena. The results of these simulations demonstrate that positive enthalpy of mixing highlighted as a necessary criterion for nanocrystalline stability in [1], also leads to the fast diffusing elements ability to form the interparticle neck. The condition of lower temperature neck formation by fast diffusing alloy elements is hypothesized to be the mechanism behind which accelerated sintering occurs. The findings in this paper demonstrate that positive enthalpy of mixing alloys can be designed to sinter at lower temperatures and shorter cycle durations if they have adequate solute present on the surface of the particle. / by Jonathan Paras. / S.B.