Massachusetts Institute of Technology. Dept. of Metallurgy and Materials Science. Thesis. 1971. Sc.D. / Vita. / Includes bibliographical references. / Sc.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1994. / Includes bibliographical references (p. 110-116). / by Timotheus Servaas Smit. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006. / Includes bibliographical references (leaves 108-115). / The human fetal membrane, namely the chorioamnion, is the structural soft tissue retaining the amniotic fluid and the fetus during pregnancy. Its biomechanical integrity is crucial for maintaining a healthy gestation and a successful delivery. The premature rupture of the fetal membrane (PROM) can result in serious perinatal complications. Despite extensive research in this field, the mechanical and biochemical processes governing the membrane deformation and failure remain poorly understood. The aim of this study is to characterize the mechanical behavior of the chorioamnionic tissue along with its biochemical properties, through mechanical testing and biochemical analyses. In order to accomplish this goal, specific mechanical and biochemical testing protocols were developed. In vitro mechanical testing was performed on samples from seven patients under different uniaxial and biaxial loading conditions. Significant relaxation was noted under uniaxial loading while very limited creep was observed under biaxial loading. Biochemical measurements such as collagen and sulfated glycosaminoglycan contents were also obtained. In addition, a microstructurally based constitutive model for the fetal membrane is proposed. / (cont.) The model allows for nonlinear hyperelastic response at large deformation. We also propose a framework to capture the time-dependent response of the tissue. The model was implemented in a finite element formulation to allow three-dimensional simulations of membrane deformation. / by Thibault Philippe Prévost. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010. / Includes bibliographical references (p. 169-177). / An ambient pressure chemical vapor deposition (APCVD) process is used to fabricate graphene based films consisting of one to several graphene layers across their area. Polycrystalline Ni thin films are used and the graphene can be transferred from the Ni surface to dielectric substrates in order to integrate them to graphene device prototypes. Uniform single layer graphene can be grown with the same process by using single crystalline Ni with a (111) surface orientation. Raman spectroscopy and electron diffraction characterization is undertaken in order to determine the nature of the layer stacking for the case of multilayer graphene. / by Alfonso Reina Ceeco. / Ph.D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 48-50). / Graphene has been regarded as a good candidate to make a breakthrough in various applications including electronics, sensors and spintronics due to its exceptional physical properties. To realize those practical applications, a high quality homogeneous wafer-scale graphene is required. Among various synthesis methods, chemical vapor deposition (CVD) has been a focus of attention as the most promising and cost-efficient deposition techniques, with advantages of its excellent repeatability and controllability, to produce large area graphene crystals on transition metal catalyst substrates. In particular, Cu with low carbon solid solubility is suitable to obtain uniform single layer deposition of graphene over large areas. Here, we report reliable method to grow high-quality continuous graphene film by CVD. Their surface properties and electrical transport characteristics are explored by several characterization techniques. In CVD process, furthermore, a subsequent transfer process to a substrate of interest is required for a wide variety of applications, especially in electronics and photonics, because the metal substrates necessary to catalyze the CVD graphene growth cannot be used. It is important not only to improve quality of as-grown graphene by optimizing growth system but also to develop transfer methods to prevent degradation in quality while transferring as-grown graphene to target substrates. In the case of wet transfer, surface tension of the liquid such as an etching agent or water contributes to make inevitable ripples, wrinkles and cracks. In this regard, we demonstrate new transfer methods by selecting a new polymeric support materials in order to reduce the number of winkles, defects and residues. / by Seong Soon Jo. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1995. / Vita. / Includes bibliographical references (leaves 37-38). / by Ann Satoko Hirahara. / M.S.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / "June 2013." Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (p. 94-96). / In both the Andean zone of South America and in Mesoamerica, copper-silver alloys were important in the production of thin, silver-colored sheet metal artifacts. This thesis examines the mechanical and physical properties of the copper-silver alloy system that are important to understanding why copper-silver alloys became central to the metallurgies that developed among prehistoric societies of the Andean zone and Western Mexico. These properties include their range of malleability, the microstructures behind their toughness, and the recrystallization and annealing behaviors that led to their development of silver-enriched surfaces. To determine these properties, a series of cold rolling, cold hammering, and annealing experiments were performed on five Cu-Ag alloys and pure copper. Results of the cold rolling and cold hammering experiments reported here indicate that over the copper-silver alloy compositional range studied, the alloys can be cold rolled without annealing to over 90% reduction in thickness. Similar reductions in thickness were also achieved in two alloys (95 wt% Cu - 5 wt% Ag and 30 wt% Cu - 70 wt% Ag) by cold hammering. The rate of work hardening and the Vickers Hardness Number, as functions of the percent reduction in thickness, are similar for alloy compositions containing between 30 wt% and 80 wt% Cu. This suggests that ancient metalsmiths likely annealed the copper-silver alloy artifacts intentionally to produce the desired silver surface color rather than for any improvement in malleability. The silver surface colors were important for their cultural associations. The recrystallization temperature for the copper-silver alloys tested (70 wt% Cu - 30 wt% Ag and 30 wt% Cu - 70 wt% Ag) is determined to be 500°C given a 30 minute anneal time. / by Shannon L. Taylor. / S.B.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2005. / Includes bibliographical references (leaf 39). / 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. / M.Eng.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006. / Includes bibliographical references (leaves 68-69). / Two potential applications of thin film phase-change materials are considered, non-volatile electronic memories and MEMS (Micro-Electro-Mechanical Systems) actuators. The markets for those two applications are fast growing and rapidly changing, so new materials technologies with superior performance are of great interest. Devices made with thin film phase change materials are shown to offer significant performance improvements for memory applications and new triggering mechanisms for MEMS actuation. IP (Intellectual Property) analyses for both markets indicate significant new IP space in each of them. Rough estimations for cost and revenue are provided. / by Qiang Guo. / M.Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 171-186). / In this thesis we lay the foundations for a distributed, community-based computing environment to tap the resources of a community to better perform some tasks, either computationally hard or economically prohibitive, or physically inconvenient, that one individual is unable to accomplish efficiently. We introduce community coding, where information systems meet social networks, to tackle some of the challenges in this new paradigm of community computation. We design algorithms, protocols and build system prototypes to demonstrate the power of community computation to better deal with reliability, scalability and security issues, which are the main challenges in many emerging community-computing environments, in several application scenarios such as community storage, community sensing and community security. For example, we develop a community storage system that is based upon a distributed P2P (peer-to-peer) storage paradigm, where we take an array of small, periodically accessible, individual computers/peer nodes and create a secure, reliable and large distributed storage system. The goal is for each one of them to act as if they have immediate access to a pool of information that is larger than they could hold themselves, and into which they can contribute new stuff in a both open and secure manner. Such a contributory and self-scaling community storage system is particularly useful where reliable infrastructure is not readily available in that such a system facilitates easy ad-hoc construction and easy portability. In another application scenario, we develop a novel framework of community sensing with a group of image sensors. The goal is to present a set of novel tools in which software, rather than humans, examines the collection of images sensed by a group of image sensors to determine what is happening in the field of view. We also present several design principles in the aspects of community security. In one application example, we present community-based email spain detection approach to deal with email spams more efficiently. / by Fulu Li. / Ph.D.