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DSpace at MIT (78,720 recursos)
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Mechanical Engineering - Master's degree

Mostrando recursos 1 - 20 de 3,170

1. CloudThink and the Avacar : embedded design to create virtual vehicles for cloud-based informatics, telematics, and infotainment - Siegel, Joshua Eric
This paper describes the development and testing results for a system of Cloudbased mirrors for physical vehicles called "Avacars." Avacars duplicate parameters from On-Board Diagnostics, accelerometers, and GPS sensors installed in a vehicle as part of the MIT CloudThink set of standards. These Avacars may then be used as input and output for a diverse set of applications. Avacars are created by a custom-designed portable cellphone used to instrument a vehicle without user intervention and stored to a secure and private server. The first section of the document details the background for the Avacar project. It describes available technology and...

2. Computational Design of Viscoelastic Gels with Tunable Mechanical Energy Dissipation - Adityan, Aarthy Kannan
The development of engineered materials that exhibit mechanical characteristics similar to biological tissues can enable testing the effect of ballistics and designing of protective equipment. The physical instability of existing tissue simulants over long times and ambient temperatures has propelled interest in using polymer gel systems that could potentially mimic the mechanical response of tissues. More generally, the capacity to tune the mechanical energy dissipation characteristics of such gels is of interest to a range of applications. The present work uses a computational approach to predict the material properties of such gels. A finite element model and simulation of an...

3. Semi-autonomous control of multiple heterogeneous vehicles for intersection collision avoidance - Ahn, Heejin
This paper describes the design of a supervisory controller (supervisor) that manages multiple heterogeneous vehicles, i.e., multiple controlled and uncontrolled vehicles, to avoid intersection collisions. Two main problems are addressed: verification of the safety of all vehicles at an intersection, and management of the inputs of controlled vehicles. For the verification problem, we employ an inserted idle-time scheduling approach, where the "inserted idle-time" is a time interval when the intersection is deliberately held idle for uncontrolled vehicles to safely cross the intersection. For the management problem, we design a supervisor that is least restrictive in the sense that it overrides...

4. An investigation of preferences for product appearance : a case study of residential solar panels - Bao, Qifang
The importance of the styling and appearance of consumer products is widely understood. This paper evaluates the appearance of a technology-oriented product, the residential solar panel, using a quantitative approach known as visual conjoint analysis. The goal of this research was to determine the design attributes that make a solar panel more visually appealing, and to understand how different visual representations may reveal consumer preference differently. Approximately 200 survey respondents were shown two kinds of images of solar panels, one of a standalone panel and the other of a panel installed on a roof. The preferences for product appearance of...

5. Analysis of randomly occurring high injection forces in an insulin delivery device - Bellows, William D. (William Devereaux)
During manufacturing scale-up of a new product, new failure modes often surface which require corrective action. However, as production numbers of an insulin injection device pass 200 million per year, testing continues to find sub-assemblies with too-high injection forces, seemingly at random. Up until now, no corrective action has been effective in preventing these problems. These non-conforming sub-assemblies cause batches to be rejected, reducing the production yield at Sanofi's Site Frankfurt Devices (SFD) production facility. This thesis describes the current state of rejected batch problem solving and explores the application of new methods to better understand the root problems and...

6. Priority queuing for raw material receiving - Bower, Andrew D. (Andrew Douglas)
The Amgen Manufacturing Ltd. facility in Juncos, Puerto Rico faces a challenge encountered by manufacturers across industries: How can they make the best use of their existing resources? As production volume and product mix increase, how are costs kept from increasing as well? This LGO internship looked to answer those questions in the context of raw material receiving for biopharmaceutical manufacturing. Over the course of the seven month project, an analytical planning tool centered on scheduling optimization and priority queuing was developed, highlighting areas for improvement. Based on insight gained from the tool, a plan was established which can reduce...

7. Chemical kinetic modeling of oxy-fuel combustion of sour gas for enhanced oil recovery - Bongartz, Dominik
Oxy-fuel combustion of sour gas, a mixture of natural gas (primarily methane (CH 4 )), carbon dioxide (CO 2 ), and hydrogen sulfide (H 2 S), could enable the utilization of large natural gas resources, especially when combined with enhanced oil recovery (EOR). Chemical kinetic modeling can help to assess the potential of this approach. In this thesis, a detailed chemical reaction mechanism for oxy-fuel combustion of sour gas has been developed and applied for studying the combustion behavior of sour gas and the design of power cycles with EOR. The reaction mechanism was constructed by combining mechanisms for the...

8. A device for debridement using high pressure water jets - Brown, Ashley (Ashley A.)
Removing devitalized tissue from chronic wounds through debridement is critical to promote wound healing. In this thesis, technology using high-speed water jets is explored toward applications for debridement. After presenting possible techniques, the thesis expands on one promising method using two impinging cutting jets that is further developed and demonstrated on simulated necrotic tissue. Surgical blades are used to score the tissue in advance of the nozzles. Vacuum suction is applied to locally evacuate waste. At optimal parameters of 75 pm orifices spaced 2 mm apart at 1100, the device was able to excise soft necrotic tissue at 6 MPa....

9. Prototyping for user feedback : how visual detail can influence feature preference - Christian, James Loren
User-centered design focuses on insights drawn from users to drive product development. Provisional design prototypes are often used as a tool for collecting feedback from users that can then be incorporated into future design iterations. However, experience from design practice suggests that user feedback should not always be taken verbatim, and that the particular context in which a prototype is presented can greatly influence the user's perception of the concept. The theory of preference construction helps design researchers understand how users' preferences are dependent on the particular context of a design representation. Thus, it is important for designers to have...

10. Design and assessment of a super high speed, hybrid hydrofoil/SWATH crew boat - Georgiadis, Vasileios
This thesis presents the preliminary design and assessment of Wavecutter, an innovative super high speed, hybrid hydrofoil/SWATH crew boat. The intended mission of the vessel is the very-fast transportation of crew and cargo, to and from offshore installations. The design builds on Brizzolara's unmanned high speed hybrid SWATH/hydrofoil vessel concept (Brizzolara, 2010), maintaining the dual operating mode: foilborne to reach top speed of 85 knots in moderate sea states and a displacement SWATH to sail in the higher sea states. This vessel is expanding the family of unmanned hybrid SWATH vessels of Brizzolara and Chryssostomidis to include manned vessels (Brizzolara...

11. Development of photo-patterned composite structures in microchannels for oil reservoir research - Lee, Hyundo
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.

12. Rational design of hybrid organic solar cells - Lentz, Levi (Levi Carl)
In this thesis, we will present a novel design for a nano-structured organic-inorganic hybrid photovoltaic material that will address current challenges in bulk heterojunction (BHJ) organic-based solar cell materials. Utilizing first principles Density Functional Theory (DFT), we show that layered inorganic phosphates and tradition organic dyes can be combined to form a new class of bulk heterojunction photovoltaic with high electron and hole mobilities with low exciton recombination, potentially enabling very high efficiency with existing organic-based solar-cell molecules. We will discuss the physical origin of these properties and investigate several approaches for engineering the electronic structure of these materials. By...

13. Precision control of cylindrical stamp contact in a continuous roll-to-roll microcontact printing machine - Libert, Adam M. (Adam Marcus)
Microcontact printing is a form of soft lithography that uses a molded elastomeric stamp to print patterns with micron and sub-micron scale features. This is an effective low-cost technique for replicating master patterns onto substrates. However, the traditional embodiment of using a planar stamp with a planar substrate is limited in both scale and speed. In order to achieve higher production rates, the lab scale plate-to-plate microcontact printing method must be developed into a roll-based manufacturing process. The marriage of the precision of microcontact printing with the speed of traditional press printing will fill a niche in manufacturing capabilities. Large...

14. Rapid 3-D laser microprinting of bioscaffolds and patterning of proteins - Liu, Man-Chi, S.M. Massachusetts Institute of Technology
Tissue engineers have been developing biological substitutes to regenerate or replace damaged tissue. Tissues contain both exquisite microarchitectures and chemical cues to support cell migration, proliferation and differentiation. The majority of tissue engineering strategies use porous scaffolds containing chemical cues for culturing cells. However, these methods are unable to truly recapitulate the complexity of the in-vivo environment, limiting the effective regeneration. Several techniques have been developed to create three-dimensional patterns of proteins and 3-D print the architectures of bio-scaffolds for studying and directing cell development. Scott has developed a rapid 3-D laser microprinting system', which is able to simultaneously print...

15. Optical proximity sensor and orientation control of autonomous, underwater robot - Lozano, Martin, Jr
Autonomous mobile robots need a reliable means of navigation to reach their target while avoiding collisions. This requires continuous knowledge of the vehicle's position, orientation, and motion as well as a way to identify their surroundings. Exploratory robots and those traveling in complex environments may have difficulty determining their global location. They often rely on data from sensors to estimate their position. While various proximity sensors have been developed for land vehicles, options for underwater vehicles are limited. We detail the design of an optical orientation sensor for fine positioning of highly maneuverable underwater robots. The sensor consists of a...

16. Process characterization of a PMMA hot embossing system - Luginbuhl, Katharine
Microfluidics devices are important both for research use and medical application. To create these microfluidics devices, the hot embossing process is commonly used. In order to characterize this process to enable cycle to cycle control, a small-scale system was developed, using a hot embossing machine, taping machine, and functional tester previously created. Parts were moved between these machines with an Epson GlO SCARA robot, which provided the appropriate efficiency and accuracy. This system was able to produce embossed parts with a takt time of less than 135 seconds, and over 1000 of such parts were produced. The system was analyzed...

17. Improvements to building energy usage modeling during early design stages and retrofits - Mandelbaum, Andrew (Andrew Joseph)
A variety of improvements to the MIT Design Advisor, a whole-building energy usage modeling tool intended for use during early design stages, are investigated. These include changes to the thermal mass temperature distribution and lighting requirement calculations, the formulation of a representative day scheme to reduce the number of days that need to be simulated to find energy usage for a full year, the creation of an optimization algorithm to allow users to improve on their designs, and the addition of an algorithm to predict potential savings from retrocommissioning (RCx) using a limited set of simple inputs. Design Advisor itself...

18. In situ control of lubricant properties for reduction of power cylinder friction through thermal barrier coating - Molewyk, Mark Allen
Lowering lubricant viscosity to reduce friction generally carries a side effect of increased metal-metal contact in mixed or boundary lubrication, for example near top ring reversal along the engine cylinder liner. A strategy to reduce viscosity without increased metal-metal contact involves controlling the local viscosity away from top-ring-reversal locations. This paper discusses the implementation of insulation or thermal barrier coating (TBC) as a means of reducing local oil viscosity and power cylinder friction in internal combustion engines with minimal side effects of increased wear. TBC is selectively applied to the outside diameter of the cylinder liner to increase the local...

19. The use of series compliance and variable transmission elements in the design of a powered knee prosthesis - Mooney, Luke Matthewson
Compared to non-amputees, above knee amputees expend significantly more metabolic energy. This is a result of the passive nature of most knee prostheses, as the development of clinically successful powered knee prostheses has remained a challenge. The addition of powered elements, such as electric motors, allow prosthetic knees to more closely emulate natural knee biomechanics. However, the addition of powered elements presents a new challenge of creating energy efficient devices that do not require frequent charging or excessively large batteries. In this thesis, a general optimization routine was developed to simulate and evaluate the electrical economy of various actuator architectures....

20. A tissue engineering strategy for integrative cartilage repair - Mroszczyk, Keri A
Tissue engineering for cartilage repair is a promising approach for improving the healing of articular defects, as biomaterials and growth factors can be supplied directly to a focal lesion. However, integrating neo-tissue with native cartilage to provide mechanical and biological continuity at the interface remains a challenge due to the limited regenerative capacity of the tissue. In an effort to improve integration, enzyme treatments were investigated as a means of functionally grafting engineered tissue to native tissue. Using an in vitro model of defect repair, this study develops a repair strategy that employs both a hydrogel (KLD) functionalized with HB-IGF-1...

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