Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000. / Includes bibliographical references (p. 245-246). / An experimental study of the micromechanisms of paperboard deformation has been conducted. Experiments were performed in a scanning electron microscope, allowing visual observation and coincident acquisition of load vs. deformation data. Deformation mechanisms were determined and correlated with features of the load vs. deformation curves for different loading modes. A macroscopic study was performed concurrently to provide accurate continuum-level load vs. deformation data. This study contributed to an effort to model the creasing process. In creasing, paperboard is punched to create an internal line of damage and then folded along that line to create a corner. It has been determined experimentally that the creasing process involves through-thickness compression and transverse shear loading, as well as in-plane tension loading. Out-of-plane delamination also plays an important role. Experiments were conducted to determine the stress-strain behavior and corresponding deformation mechanisms under several well-controlled loading conditions. These include through-thickness compression, shear, and tension, as well as combined tension/shear loading. In-plane tensile behavior was also investigated. Paperboard loaded in out-of-plane compression behaved linearly at small strains, with an exponential increase in stiffness at larger strains. Deformation mechanisms included void closure and fiber collapse. In out-of-plane shear, paperboard initially behaved linearly, but departed from linearity before a peak in load. The dominant failure mechanism at the microscopic scale was sudden fiber disengagement throughout the entire cross-section, corresponding to the peak in load. Loaded in out-of-plane tension, the paperboard first exhibited many small cracks at the interfaces between layers. As these cracks grew, one became dominant, and all further delamination occurred by extension of that crack. Similar behavior was observed in combined loading experiments with tension as the larger load component. With shear as the larger component, delamination generally occurred suddenly rather than being preceded by small local cracks. In-plane tensile behavior also included an initial linear region, followed by nonlinearity and a peak in load. The dominant mechanisms were fiber break and fiber disengagement in the different layers of the board; this again corresponded to the ... [missing rest of abstract] / by Heather M. Dunn. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 147-150). / Avoiding knock is the major design constraint for spark ignition engines because of the unacceptable noise and engine damage associated with it. Hence, the Research and Motor Octane Number (RON and MON) tests were established in 1928 such that a fuel with a higher RON and MON is less likely to knock than a fuel with a lower value. However, engine and fuel technology has evolved since 1928, and thus the relevancy of these tests for modem engines needed to be evaluated. First, the study compared knock onset, knock metrics, reference fuels, and test conditions for the octane tests to those in modem engines. The results showed that in modem engines, for a given RON, fuels with lower MON values performed better than fuels with higher values, and this trend becomes stronger when engines are boosted and intercooled. Second, detailed chemical kinetics models were used to study fuel autoignition phenomena leading to knocking conditions. These models showed that the fuel autoignition chemistry in modem engine is different from that in the RON and MON tests. Based on these results, it was concluded that the RON and MON tests no longer represent modem engine operating conditions; therefore, modifications are suggested and evaluated to improve the tests' applicability. / by Vikram Mittal. / Ph.D.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 61-63). / Many biomarker-based diagnostics have poor predictive value because of their dependence on naturally occurring endogenous biomolecules to indicate disease. This work presents a diagnostic platform that uses nanoparticles to profile underlying proteolytic signatures of diseases. In this thesis, work is presented on long circulating peptide-nanoparticle probes that can survey, sense, and remotely report on dysregulated protease activities in cancer. In this strategy, iron oxide nanoparticles are utilized as chaperons to deliver protease-specific peptide libraries to tumors whereupon selective cleavage by active proteases releases peptide fragments that are cleared by the renal system into the urine. These peptide fragments are pre-designed with internal photolabile triggers that un-cage isobaric peptide mass tags optimized for multiplexed LC MS/MS quantification. Results demonstrate that such peptide 'synthetic biomarker' panels uncover unique proteolytic signatures that can be correlated with disease states, allowing for the detection of cancer and potential long-term monitoring of disease using an implantable form. This concept of administering prodiagnostic reagents and analyzing remote reporters is amenable to a broad range of protease-dependent complex diseases, such as liver fibrosis and coagulopathies, and infectious disease. / by Omar O. Abudayyeh. / S.B.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 77-84). / Telepresence robots have emerged as a novel solution to meeting the social communication needs of nomadic workers. This thesis provides an overview of non-verbal communication cues for telepresence robot applications, and a snapshot of the competitive landscape for commercially available telepresence robots today. It then follows the design of a low-cost telepresence robot which can be remotely operated whilst running Skype, and discusses how further non-verbal communication cues could be incorporated to increase the feeling of social presence. Specifically, face tracking and the ability to communicate gaze is developed in the final prototype. / by Jennifer S. Milne. / S.M.

Thesis (Mech. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1987. / Bibliography: leaves 117-118. / by John Kyratzoglou. / Mech.E.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 67-68). / This report includes a discussion of the potential production of stranded natural gas reserves through the implementation of Floating Liquefied Natural Gas (FLNG) in a world of growing energy demand followed by an analysis of the technology's economic feasibility. The economic analysis aims to use production and expense estimates related to Shell's Prelude FLNG project in order to determine the project's FOB breakeven price. The net present value (NPV) of the project's discounted future cash flows is used to determine this breakeven price. The results of the economic analysis revealed the FOB breakeven price of Shell's Prelude project to be $8.16 per MMBTU, a reasonable calculation given current breakeven price estimates for similar projects in the area. Even with a 15% error band in Shell's production estimates, the breakeven price remained in the range of $8-$9 per MMBTU. However, when the production of lean natural gas was considered, the breakeven price exceeded $12 per MMBTU, a price that is, based upon current forecasts, too high to warrant consideration of such a project. It was found that with production incentives, such as LPG and condensate, the current FLNG design can prove to be economically successful, given the current LNG price forecasts. However, for the production of stranded reserves lacking these production incentives, a separate lean FLNG design should be considered. / by Phillip Christian Marmolejo. / S.B.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 29). / RoboClam 2 is a device that burrows based on the movement of the Atlantic razor clam. A functional RoboClam 2 has been built. Testing was conducted in a controlled laboratory environment to determine what parameters of the device and its operation affect its ability to dig both speedily, deeply, and efficiently. Smaller contraction and dilation volume, heavier device weight, and longer contractions above a theoretically calculated minimum fluidizing velocity were all found to correlate with faster digging speed. Future work will involve experimentally determining the minimum fluidizing velocity and the effect of contraction speed on digging ability. / by Steven Paul Guitron. / S.B.

Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 19). / In high performance waterproof clothing, seam tape and welds fail before other parts of the garment. This paper examines a method of sealing seams in which the needle waterproofs the holes it creates by sealing them with a film of a thickness governed by the Landau-Levich law. The equation governing Landau-Levich behavior is combined with equations describing hole geometry to develop a phase space describing the fluidic and geometric properties necessary to seal a hole. A manual proof of concept test is performed which demonstrates that the basic method works. The needle speed of a standard sewing machine is then measured as is the size of the hole made by a standard sewing machine needle. These values are then used to calculate the viscosity of a fluid that will satisfy the conditions described by the phase space. An adhesive with the calculated viscosity is made and is used on a test bed to seal holes made by a needle. Each individual hole is sealed and further tests show that the seals are waterproof. Both the proof of concept and test bed experiments confirm the theory and it is concluded that needle speed, film length, and viscosity are the variables that can be controlled to tune hole sealing. / by Cole Houston. / S.B.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1989. / Includes bibliographical references (leaves 55-56). / by Helen Greiner. / B.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005. / Includes bibliographical references (leaf 25). / The effects of ion orbits on pitch angle scattering of fast ion beam injection are investigated here for the magnetic equilibrium of the ITER tokamak. Two methods are used to calculate distributions in the presence of orbits, one applying boundary conditions a posteriori and one a priori. In both cases an orbit average of the Fokker-Planck equation is taken, yielding a solution in velocity space variables velocity and pitch angle. In the first case, conditions in the form of a linear combination of co, counter, and trapped distributions or fluxes are matched at the orbit transition value of pitch angle so that several distributions combine to form a solution. In the second case, an overall distribution is found which obeys boundary conditions derived from the trapped and passing regime essential behavior. Ultimately, both methods yield distributions which are essentially equivalent in character. / by Joseph J. Wleklinski. / S.M.