Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1993. / Includes bibliographical references (p. 69-70). / by Stephen Ueda. / M.S.

Thesis (Sc.D.) Massachusetts Institute of Technology. Dept. of Mechanical Engineering, 1953. / Vita. / Bibliography: leaves 37-39. / by Robert Siegel. / Sc.D.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008. / Characterizing transient flow is not a trivial venture. It provides an excellent challenge for a senior mechanical engineering lab class. This project aimed at developing a new physical system for such a class based on the benefits and short comings of the previously used physical system. A physical system was developed to vary key parameters, such as run length and pipe diameter. Pipe diameter was previously not a variable parameter. The physical system was designed to help the operator's intuition in developing a mathematical model for said system. The design incorporated solenoid valves and clear pipe. In contrast to the previous system that used ball valves and copper pipe. These features were chosen so that those using the system could neglect human error and visually inspect the flow. The system was designed to increase variation between runs so that a more robust model could be developed. The flexibility of the physical system allows for the examination of more complex flows than the previous system. The mathematical model that was developed characterized the flow reasonably well. The unsteady Bernoulli equation was implemented with major and minor losses. The model revealed several aspects of the physical system that were not immediately obvious from the data. The unpredicted aspects of the physical system were the fluctuation in tank pressure over the test duration and the correlation between tank pressure and the loss coefficient of the main solenoid valve. The higher the pressure the lower the loss coefficient across the valve. The mathematical model did not account for losses that increase as the water air interface moves through different fittings. This was a major shortcoming of the mathematical model that was developed. / by Matthew S. Humbert. / S.B.

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical 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 51-56). / This thesis aims to enable virtual and augmented reality (VR/AR) systems to track objects accurately through occlusions via RFID localization. Currently, three major obstacles prevent the use of RFID localization in VR/AR systems: (1) there exists a trade-off between measurement speed and ability to deal with multipath, so systems which can produce accurate results either require a highly constrained environment or several seconds to localize; (2) past RFID localization techniques lack robustness to changes in tag orientation; and (3) current RFID orientation extraction methodologies are largely inaccurate. To overcome these challenges, this thesis presents RF-Reality, a new system that leverages a novel OFDM backscatter technique and differential channel estimation algorithm to perform accurate, rapid RFID position and orientation recovery. / by Nicholas Stearns Selby. / S.M.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006. / Includes bibliographical references (p. 52-53). / Polymer nanofibers hold much promise as advanced composite materials, and can be customized into matrices with special electrical, optical and biological properties. Electrospinning, which utilizes the destabilization of a fluid's surface in a strong electric field, has gained the most favor as a top-down approach to producing polymer nanofibers. In this work, a microfluidic device was designed and assembled for the two-dimensional focusing of immiscible fluids and integrated into a system for electrospinning. Hollow fibers were produced with diameters on the order of 100-240 nm, at steady-state flow rates around 50 pL/min. TEM images show hollow interiors with diameters approximately one third of the total fiber diameter. These results are important for future efforts at multiplexing the electrospinning process, and prove that the creation of hollow fibers is feasible using a microfabricated device. Furthermore, the focusing of immiscible streams in two dimensions may be used for sample transport and reaction control in microfluidics. Suggestions are made for further evaluation of flow focusing behavior, and improvements that may increase the viability of electrospinning as an industrial process. / by Christopher R. Rhodes. / S.B.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1904. / by J. W. Crowell. / B.S.

Thesis (S.M. in Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 111-115). / Contra-rotating propellers have renewed interest from the naval architecture community, because of the recent development of electric propulsion drives and podded propulsors. Contrarotating propulsion systems have the hydrodynamic advantages of recovering part of the slipstream rotational energy which would otherwise be lost utilizing a conventional screw propeller system. The application of this type of propulsion becomes even more attractive with the increasing emphasis on fuel economy and the improvement of the propulsive efficiency. OPENPROP is an open source propeller design and analysis code that has been in development at MIT since 2007. This thesis adds another feature to the project with the off design analysis of a contra-rotating propeller set. Based on this code, the thesis offers a comparative analysis of two types of propulsors: a single propeller and a contra-rotating propeller set, which were designed for the DDG-51 destroyer class vessel. This thesis also presents the method for using these off-design analysis results to estimate ship powering requirements and fuel usage. The results show the superiority of the contra-rotating propeller over the traditional single propeller, with increased propeller efficiency of about 9% at the design point and up to 20% at some of the off design states. The annual fuel consumption savings for the DDG-51 equipped with a CRP was a total of 8.8% fuel savings. / by Eyal Kravitz. / S.M. / S.M.in Naval Architecture and Marine Engineering

Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 65-66). / This thesis utilizes concepts taken from the NAVSEA Design Practices and Criteria Manualfor Surface Ship Freshwater Systems and other references to create a Cooling System Design Tool (CSDT). With the development of new radars and combat system equipment on warships comes the increased demand for the means to remove the heat generated by these power-hungry systems. Whereas in the past, the relatively compact Chilled Water system could be tucked away where space was available, the higher demand for chilled water has resulted in a potentially exponential growth in size and weight of the components which make up this system; as a result, the design of the cooling systems must be considered earlier in the design process. The CSDT was developed to enable naval architects and engineers to better illustrate, early in the design process, the requirements and characteristics for the Chilled Water system components. Utilizing both Excel and Paramarine software, the CSDT rapidly creates a visual model of a Chilled Water system and conducts pump, damage, cost, weight, and volume analyses to assist in further development and design of the system. Several case studies were run to show the capability and flexibility of the tool, as well as how new electronic and mecahnical systems can affect the parameters of the Chilled Water system. / by Ethan R. Fiedel. / Nav.E.and S.M.

Thesis (S.B.)--Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 44). / The design process for an experimental platform measuring reaction kinetics in a chemical looping combustion (CLC) process is documented and justified. To enable an experiment designed to characterize the reaction kinetics of the reduction/oxidation cycle in a rotary channeled oxygen carrier, a platform was designed to deliver controlled conditions of temperature and gas flow around a central disc of oxygen-carrier material and determine the rates of oxidation and reduction using real-time gas analysis (RTGA). In order to deliver precise and accurate results, it was necessary to identify and either minimize or compensate for interfering factors such as gas turbulence, temperature fluctuation, and flow equipment response time delays. This paper serves as a progress report on the experimental reactor; the overall design process is discussed, including equipment selection, reactor design, electronics and control hardware setup, and software interface design, and the current state of the reactor is discussed, including an assessment of the current capabilities and drawbacks of the system, future work, and potential methods for improvement. / by Jack Jester-Weinstein. / S.B.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 47-53). / Considering that contacts between liquid and solid are ubiquitous in almost all energy processes, including steam turbines, oil pumping, condensers and boilers, the efficiency of energy transportation can be maximized such that the liquid-solid interaction is optimized. Texture based super-hydrophobicity, also known as the Lotus effect, has been one of the most extensively studied topics in the last decade. Many of the recent studies have focused on how textures induce more water repellency, and how these textures can be manufactured with different methods and materials. However, few studies have shown how these surfaces benefit the real energy processes in which the interaction between liquid droplets and solid surfaces is vigorous and influences the energy transfer performances. This work focuses on altering the hydrodynamics of droplets with nano-engineered surfaces such that it enables a variety of energy transport processes to achieve better efficiency. Firstly, the wetting transition on textured super-hydrophobic surfaces is explored. The careful investigation of Cassie-Baxter to Wenzel transition of a pendant drop during the deposition explains that the rapid deceleration-induced water hammer pressure causes the transition. This new transition mechanism for large droplets enables a new wetting transition phase diagram with a previously known Laplace mechanism that explains the small drop transition. Another class of non-wetting droplet, the Leidenfrost drop, is studied with textured super-wetting surfaces. The liquid drop loses its contact to the solid by its own vapor, created by a large superheat from the solid. The Leidenfrost effect is undesirable in cooling applications as the vapor layer acts as a barrier for heat transfer. Here, it has been studied that how textured super-hydrophilic surfaces induce droplets to wet at higher superheat via capillary wicking compare to smooth surfaces. A physical model based on scaling is developed to predict the Leidenfrost drop on single length scale textures, and validated by the experiments. Additionally, the physical mechanism suggests that hierarchical textures have a higher Leidenfrost temperature compared to single-length-scale textures, confirmed experimentally. Lastly, the recently discovered rare-earth oxide ceramics are studied, which ensures the benefits of water repellency under harsh conditions such as high temperature and abrasive wear. Texturing of the rare-earth oxide ceramic is explored by the laser ablation technique. Unique micro- and nano-scale hierarchical textures are created, enhancing the water repellency, resulting in the super-hydrophobic rare-earth ceramic. / by Hyuk-Min Kwon. / Ph. D.