Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1996. / Includes bibliographical references (leaves 79-80). / by Corey J. Foster. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, February 2004. / Includes bibliographical references (p. 200-215). / The first step in two of the most troublesome biological responses to the implantation of blood-contacting biomaterials, i.e. thrombosis and inflammation, is the adhesion of blood plasma proteins to the biomaterial surface, which may then initiate platelet adhesion and activation, and thereby set in motion a cascade of adverse host responses. If devices could be developed that prevent that first step from occurring altogether, a new generation of "stealth" biomaterials would be born. Such was the motivation of this project, which sought to investigate the constituent intermolecular interaction forces governing protein adhesion to biomaterials, using the technique of high resolution force spectroscopy. The model protein chosen for our study was human serum albumin (HSA), the smallest and most abundant blood protein in the human body, and typically the first to adsorb to a blood-contacting, implanted device. In the first stage of our investigation, HSA was covalently grafted to a nanosized probe tip at the end of a soft, microfabricated cantilever force transducer. The intermolecular interaction potential, U(D), was recorded between the HSA-modified probe tip and four different model surfaces, including: 1) gold, 2) a hydrophobic, CH3-terminated alkanethiol self-assembling monolayer (SAM), 3) a hydrophilic, COO-terminated alkanethiol SAM, and 4) individual, covalently end-grafted molecules of poly(ethylene oxide), in aqueous sodium phosphate buffer solution (PBS, ionic strength IS = 0.01M, pH = 7.4). Both theoretical and numerical modeling were employed to evaluate the experimental results on each of the different surfaces, and to characterize the nature of the protein-bound probe tip. In the second part of this study, / (cont.) we aimed to elucidate the various constituent intermolecular interaction forces contributing to U(D) by strategically manipulating experimental conditions such that we were able to isolate, and in some cases quantify, the electrostatic, steric, and hydrophobic components. It was found theoretically that electrostatic and steric forces accounted for approximately 8% and 4% of the total intermolecular interaction force; experimentally, these forces are observed to be completely dominated by a repulsive force which increases in magnitude as the ionic strength of the solution is increased. It is believed that this additional force is imparted by the PEO, and may be due to a change in the conformation of the PEO coil, or the structure of the network of water molecules in the space between the PEO coil and the approaching probe tip. The hydrophobic component was experimentally quantified to be approximately 20% of the total intermolecular interaction force at D [approx.] 1 nm. In the third part of this investigation, we sought to study the interactions between HSA and a series of oligosaccharide-functionalized surfaces inspired by the glycocalyx, which coats all living cells and is naturally and necessarily hemocompatible. The results of this study were then compared to experiments conducted in parallel on poly- and oligo(ethylene oxide) modified surfaces. Our results suggest that higher oligosaccharides ... / by Monica Ann Rixman. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 215-218). / The most prevalent criticism of fission-fusion hybrids is simply that they are too exotic - that they would exacerbate the challenges of both fission and fusion. This is not really true. Intriguingly, hybrids could actually be more viable than stand-alone fusion reactors while mitigating many challenges of fission. This work develops a conceptual design for a fission-fusion hybrid reactor in steady-state L-mode tokamak configuration with a subcritical natural or depleted uranium pebble bed blanket. A liquid lithiumlead alloy breeds enough tritium to replenish that consumed by the D-T fusion reaction. Subcritical operation could obviate the most challenging fuel cycle aspects of fission. The fission blanket augments the fusion power such that the fusion core itself need not have a high power gain, thus allowing for fully non-inductive (steady-state) low confinement mode (L-mode) operation at relatively small physical dimensions. A neutron transport Monte Carlo code models the natural uranium fission blanket. Maximizing the fission power while breeding sufficient tritium allows for the selection of an optimal set of blanket parameters, which yields a maximum prudent fission power gain of 7.7. A 0-D tokamak model suffices to analyze approximate tokamak operating conditions. If the definition of a "reactor" is a device with a total power gain of 40, then this fission blanket would allow the fusion component of a hybrid reactor with the same dimensions as ITER to operate in steady-state L-mode very comfortably with a fusion power gain of 6.7 and a thermal fusion power of 2.1 GW. Taking this further can determine the approximate minimum scale for a steady-state L-mode tokamak hybrid reactor, which is a major radius of 5.2 in and an aspect ratio of 2.8. This minimum scale device operates barely within the steady-state L-mode realm with a thermal fusion power of 1.7 GW. This hybrid, with its very fast neutron spectrum, could be superior to pure fission reactors in terms of breeding fissile fuel and transmuting deleterious fission products. It could operate either as a breeder, producing fuel for pure fission reactors from natural or depleted uranium, or as a deep burner, fissioning heavy metal and transmuting waste with a cycle time of decades. Despite a plethora of potential functions, its primary mission is deemed to be that of a deep burner producing baseload commercial power with a once-through fuel cycle. Although hybrids are often purported a priori to pose an elevated proliferation risk, this reactor breeds plutonium that could actually be more proliferation-resistant than that bred by fast reactors. Furthermore, a novel method (the "variable fixed source method") can maintain constant total hybrid power output as burnup proceeds by varying the neutron source strength. As for engineering feasibility, basic thermal hydraulic analysis demonstrates that pressurized helium could cool the pebble bed fission blanket with a flow rate below 10 m/s. The Brayton cycle thermal efficiency is 41%. This device is dubbed the Steady-State L-Mode Non-Enriched Uranium Tokamak Hybrid (SLEUTH). The purpose of this work is not any sort of elaborate design, but rather the exploration of an idea coupled with corroborating numerical analysis. At this point in the hybrid debate, viable conceptual designs are persuasive while intricate build-ready designs are superfluous. This work conceives such a conceptual design, demonstrates its viability, and will perhaps, incidentally, spur a profusion of pro-fusion sentiment! / by Mark Wilbert Reed. / S.M.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007. / Includes bibliographical references. / The discovery of high brightness (white) light emitting diode (LED) is considered as a real threat to the current lighting industry in various applications. One of the most promising sectors would be using white LED to replace the current Cold Cathode Fluorescent Light (CCFL) technology as the backlight of the large screen Liquid Crystal Display (LCD) screen due to the fact that LCD is a rapidly booming market. / by Chian Myau Soon. / M.Eng.

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, June 2016. / 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 (page 35). / Thin film BCZT was processed, optimized, and analyzed from powder to ceramic to film for use in a capacitive thermos-electric converter. The idea of using a temperature dependent dielectric to turn heat into electricity has been around for several decades but has never been feasible due to low efficiency and the practical difficulty of being able to thermally cycle the dielectric material quickly enough. However, thin film materials are able to be thermally cycled at high enough frequencies. One material that has potential to be used as the dielectric in a capacitive thermo-electric converter is Ba(TixZr1-x)O3-(BayCa1-y)TiO3. Known as BCZT, this perovskite has previously been studied as an alternative to piezo electrics which are traditionally made with lead. BCZT has a very high dielectric constant of several thousand and, because of its triple point just above room temperature, the dielectric constant is temperature dependent around room temperature. In this paper, BCZT is studied for its potential as a thin film dielectric material in a capacitive thermo-electric converter. Several different compositions around the triple point are created from powder sources, sintered into targets for PLD, analyzed, and the most promising composition was deposited into a thin film and patterned with in-plane capacitor contacts. Analysis using XRD and dielectric measurements was done at several stages. / by Emily Thomson. / S.B.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008. / Includes bibliographical references (p. 39-43). / A novel processing method was developed for sub-50 nm structures by integrating quantum dots (QDs) on patterned polymer substrates. Poly(styrene-alt-maleic anhydride) (PSMa) was prepared by the initiated chemical vapor deposition (iCVD) method, an alternative to spin-on deposition. The sub-50 nm PSMa polymer patterns were prepared by low energy oxygen plasma etching by using CNTs as the masks. The water soluble, amine-functionalized QDs underwent the nucleophilic acyl substitution reaction with the PSMa containing anhydride functional groups. This integration method is use to incorporate high performance QDs on inexpensive, lightweight flexible substrate. / by Chia-Hua Lee. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2002. / Includes bibliographical references (p. 125-135). / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Fretting fatigue is defined as damage resulting from small magnitude (0.5-50 microns) displacement between contacting bodies where at least one of the bodies has an applied bulk stress. The applicability and limits of a fracture mechanics based life prediction is explored. Comparisons are made against highly controlled experiments and less controlled but more realistic experiments using a novel dovetail attachment fixture. Surface engineering approaches are examined from a mechanics perspective. Using a new tool, depth sensing indentation, the mechanical properties of an aluminum bronze coating are determined. Fretting fatigue experiments are performed on specimens coated with aluminum bronze and on specimens treated with low plasticity burnishing. Low plasticity burnishing is a new method of introducing beneficial compressive residual stresses without significant cold work at the surface. A mechanics based approach to the selection of palliatives is addressed. / by Brett P. Conner. / Ph.D.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998. / Includes bibliographical references (leaf 32). / by Douglas J. Harris. / B.S.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008. / Includes bibliographical references (leaves 56-58). / With the increasing demanding of bandwidth in information technology, electronic connections meet the limitation in high speed processing in shorter and shorter reach. In the work, three markets for optical connection with different reach, which range from 10km down to 1 meter, have been discussed. The 10km market denotes for the LAN standard and would mature soon. For the 100m range, active cable has emerged to meet the requirement and would penetrate the market soon. The detail analysis would be addressed on 1-10 meet market, where electronic cables have just met the limitation. Cost modeling and business plan has been conducted. After that, the conclusion and suggestions would be made on that reach. / by Jia Luo. / M.Eng.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 29). / MIT policies set forth by the Department of Environment, Health, and Safety (EHS) require that all laboratories maintain a chemical inventory to properly document the use of hazardous chemicals. While EHS has provided a chemical inventory management tool called ChemTracker to help labs to do so, it is estimated that less than 20% of laboratories utilize the software. As a result, an EHS committee has been formed to re-evaluate ChemTracker and explore other options for inventory management. RFPs have been sent to potential vendors to determine if alternatives can better satisfy the goals of EHS and attain the benefits of effective chemical management. To analyze the problem of low usage rates of ChemTracker, interviews were conducted with research groups within the Department of Materials Science & Engineering (DMSE). These revealed that the largest variables were the number of chemicals used by the lab and the user-friendliness of the software. The initial time investment to switch from current, simpler methods to ChemTracker discouraged many smaller labs from pursuing that option. Current users of ChemTracker also expressed frustration with auto-fill features that weren't comprehensive and thus hindered the process of entering and updating inventory. Future work should expand into other departments to observe usage behavior and concerns and compare to those within DMSE. Any chemical inventory management software should be user-tested prior to full Institute implementation to ensure adoption by a larger proportion of groups around campus. While compulsory software would also ensure adoption, a one-size-fits-all approach is not appropriate for chemical tracking due to the hassle it could create and the potential impact on productivity of research itself. Thus, further analysis of user concerns and better marketing of the tools to address those concerns are required for a successful solution to the problem. / by Valerie Jing-chi Chia. / S.B.