Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 49-50). / Starting from unstructured glass microchannels, we develop a new method of micromodel fabrication. We build composite structures in a bottom-up manner with ultraviolet projection lithography where the composite structures are composed of tricyclodecane dimethanol diacrylate and stearic-acid treated calcium carbonate particles. This lithographic method is simple, fast, economical, and versatile compared with previous fabrication methods used for two-phase porous media micromodel experiments. With the micromodels developed in this way, we conduct oil-water two-phase flow experiments around a single cylindrical post with controlled oleophilic/hydrophilic wetting behavior. / by Hyundo Lee. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1992. / Includes bibliographical references. / by Vijay Krish. / M.S.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008. / Includes bibliographical references (p. 73). / With the confirmation of experiments, two new concepts about diffusion-driven flow are discussed and demonstrated. Although Phillips- Wunsch flow has been shown to exist along sloping boundaries, it is shown here that even an obstruction layer with only vertical walls produces a type of diffusion-driven flow. This is demonstrated through the execution of a dye test. Additionally, the influence that impermeable obstructions have on the density evolution of a stratified fluid is developed theoretically and demonstrated experimentally. With the use of two different types of obstruction layers, the theory is shown to accurately predict the density evolution. / by Michael R. Allshouse. / S.B.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998. / Includes bibliographical references (leaves 87-89). / by Aleksandar M. Kojić. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 122-124). / This document details the conception, design, and testing of a series of prototype powder-pelletizing devices for use with an ice confection powder produced using a CO2 spray freezing process. The device must function at a temperature of 233 K and at pressures of up to 12 bar(a) and must produce at least 500 pellets for use in consumer testing. Design considerations include stress analysis for critical parts, minimization of powder flow path length, formulation of requirements of thermal management system, implementation of the powder compression methods, examination of various agitation methods, and the testing of the prototype apparatus. Trials proved the concept sound as several dozen pellets could be produced using the final prototype. However, ensuring sufficient powder flow for the consistent and continuous production of full-sized pellets is the key difficulty in the implementation of this device. As such, further work should be devoted toward understanding and quantifying the flow properties of the CO2 flash freezing powder. / by David M. Lopez. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references. / Cell-mediated mechanical forces drive closure of severe wounds in adult mammalian organs, including the sciatic nerve following neurotmesis. Without experimental intervention the defect closes rapidly via contraction of transected nerve stumps by a thick, cohesive capsule of myofibroblasts (MFB) and subsequent collagen synthesis (scar), leading to a painful neuroma. Despite considerable progress in regenerating injured peripheral nerves with biomaterials, adequate recovery is generally limited to inter-stump gap lengths of about 20-30 mm in humans. Observations of successful induced regeneration in adults coincide with reduced MFB formation, yet the direct effect of the MFB capsule on nerve regeneration is unknown. According to the pressure cuff theory, a transected peripheral nerve could heal by regeneration, rather than MFB-mediated contraction and scar formation, provided the MFB capsule size (and corresponding cellular forces applied) are reduced. A well-characterized library of type I collagen tubular scaffolds with identical chemical composition and pore size, and varying degradation rate was used to evaluate the ability of a porous scaffold to block MFB contraction after injury in a demanding model of peripheral nerve regeneration in the adult rat. At 9 weeks post-neurotmesis, the MFB capsule thickness, 5, around the regenerating nerve was measured and the correlation with several quantitative measures of the quality of nerve regeneration, Q, was evaluated. A negative, statistically significant association was observed between the contractile capsule thickness, 6, and the quality of axonal regeneration, Q, (consisting of measures of regenerate area, the number of myelinated fibers, and the number of largediameter fibers) at 9 weeks post-sciatic neurotmesis. This constitutes the strongest evidence to date that capsules of contractile MFB antagonize induced regeneration of severely injured peripheral nerves in the adult mammal. Collagen devices of intermediate degradation rate minimized 5 and maximized Q. Reduced contractile cell presence and disrupted organization inside moderately cross-linked scaffolds that consequently degraded at an intermediate rate, but not in highly cross-linked scaffolds that degraded at very low rate, support the hypothesis of cell escape from the wound (making use of scaffold permeability) as a mechanism for scaffold regenerative activity. / by Eric C. Soller. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1993. / Includes bibliographical references (p. 140-141). / by Michael Kahan. / M.S.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1990. / Includes bibliographical references (leaf 58). / by Stephanie Christine Patterson. / B.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2003. / "May 2003." / Includes bibliographical references. / by Adam D. Wachsman. / S.M.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 30). / An experiment was carried out in order to determine the frequencies experienced in two locations on the stick during two different field hockey hits, the push and the strike. The results from these experiments showed that the top hand during a hit experiences a higher resonant frequency. During the push the top hand experienced an average resonant frequency of 349.1 Hz, compared to the lower hand which experienced an average resonant frequency of 43.95 Hz. During the strike the top hand experienced an average resonant frequency of 197.8 Hz, compared to the lower hand which experienced an average resonant frequency of 24.41 Hz. A second experiment was carried out in order to determine how effective the grip was at dissipating frequencies. The results determined that the grip is most effective over the frequencies of 117 Hz-470 Hz. Both an old and new grip were tested. The new grip was slightly more effective over the frequencies of 117 Hz - 235 Hz, and similar over the frequencies 250 Hz - 470 Hz. From these experiments it was concluded that field hockey grips are most needed and effective on the shaft of the field hockey stick. / by Morgan Gulliver. / S.B.