Recursos de colección

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Mechanical Engineering - Master's degree

Mostrando recursos 1 - 20 de 3.360

  1. Design, modeling, and validation of an apical flow Transwell insert for small intestinal models

    Nguyen, Transon Van
    This thesis presents the design, modeling and experimental validation of a device that allows for apical flow over an in 'vitro small intestine model. The device is designed to interface with commercially available hanging Transwells. Design considerations and specifications are discussed, based on user considerations, mechanical requirements, and biological requirements. To create a more informed design, multiple phenomena are modeled and results are used to modify design characteristics and give insight into viable operating parameters, such as apical flow rate. Within the device, velocity profiles of media flow as well as oxygen transport and cellular oxygen consumption are modeled. External...

  2. Engineering M13 bacteriophage platforms for cancer therapy applications

    Tsedev, Uyanga
    Two novel schemes for engineering M13 bacteriophage for application in the diagnosis, imaging and treatment of human tumors are proposed. Firstly, by exploiting the uniquely malleable biology of the M13 filamentous phage, we have engineered filamentous phages of shorter lengths by constructing our own set of small viral ssDNA that are packaged by M13 capsid proteins. These 'inho' phages can be sized to ~50nm and above in length. The small phage retains the M13 major and minor coat proteins which have previously been manipulated to serve as tethers to carry various therapy and imaging agents and target specific cancer sites....

  3. Real time bottom reverberation simulation in deep and shallow ocean environments

    Miller, Thomas Edward, S.M. Massachusetts Institute of Technology
    Due to the costs involved and time required to perform experiments at sea, it is important to provide accurate simulations of the ocean environment. Using the ray tracing code, BELLHOP, the Mission Oriented Operating Suite (MOOS), methods outlined by the Naval Research Laboratory (NRL) for bottom reverberation, and MATLAB, a model will be developed to incorporate the effects of bottom reverberation into the BELLHOP suite of code. This will be accomplished by using BELLHOP to generate a ray trace and eigen ray file. Then a MATLAB script will take the BELLHOP information and calculate the reverberation level using the NRL...

  4. The Education DesignShop : broadening non-designers' solutions for big issues

    Artiles, Jessica A
    Education in America can benefit from innovation. Creating problem-solving and inventive, innovative thinking from a diverse array of people and experiences can help redefine and reinvent this important public mission. Hackathons are collaborative, short sprints that offer such collaboration opportunities. While usually coding marathons, hackathon-type events like an Education Designathon and Education DesignShop have been developed by the researcher to tackle broad, systemic issues, here within the context of education, with tools and processes from design thinking. Two research questions are explored, with novel metrics and methods developed for each: 1) How do non-designers transform into design thinkers from the...

  5. Constitutive model of aligned carbon nanotube/nafion nanocomposite ionic electroactive polymer actuators

    Jacobs, Douglas S. (Douglas Scott)
    Research is progressing rapidly on composite nano-structured materials, including aligned carbon nanotube (A-CNT) polymer nanocomposites (PNC), and with device construction utilizing these novel materials. However, the material constitutive relations of the PNCs and tailoring of these is lagging. In this work, A-CNT and Nafion PNC electrodes are manufactured and investigated as the key active element in ionic-electroactive polymer (i- EAP) devices. i-EAP actuators are known to create relatively large strains with low input voltages, and could therefore be used for future high-strain actuation mechanisms such as synthetic muscles, microfluidic drug delivery, or low-frequency energy harvesting. Tailoring the PNC is accomplished...

  6. Purity matters : enhancing carrier transport properties in tin sulfide for photovoltaic applications by reducing impurity content

    Polizzotti, Alex J
    Tin sulfide (SnS), a potential p-type absorber material for photovoltaic applications, is hampered by poor carrier-transport properties, particularly minority-carrier lifetime. This study investigates the role of intrinsic and extrinsic crystallographic point defects on the electronic transport properties of SnS. High-purity SnS is grown via sulfurization of tin films, and compared with baseline material made from feedstock with two orders of magnitude higher impurity content. Minority-carrier lifetime, morphology, and impurity content are analyzed in both materials. It is shown that improving feedstock purity by two orders of magnitude results in an improvement to minority-carrier lifetime from under 100 ps to over...

  7. A framework for extending visual brands to new products

    Björkdal, Douglas H
    Visual design has become an increasingly important product differentiation tool for companies. By deploying a consistent visual design language that communicates brand-specific values, a company can foster recognition for its brand as a whole. When a brand seeks to launch a new product, it can take advantage of its established brand recognition, by extending its visual language to the new product. In doing so, the brand increases the new product's ability to be recognized. Supportive branding tools for industrial designers are lacking, yet strategic decisions related to visual design have become increasingly important. The objective of this thesis was to...

  8. Precision constraint of deformable bodies for medical imaging applications

    Dias Carlson, Rachel (Rachel A.)
    The purpose of this work is to learn how the performance of a constraint system that interfaces with nonlinear elastic materials such as biological tissue can be predicted by a model. The direct application of this work is the determination of the feasibility of restraining awake and anesthetized mice skulls to submicron levels of movement for biological imaging applications without direct attachment to the skull. A device capable of restricting mouse skull movement to less than a micron in every direction without requiring the rigid attachment of a fixture to the skull would enable studies of bone marrow activity that...

  9. Characterization of gait energetics for electrically actuated quadrupeds

    Evans, Kathryn Louise, S.M. Massachusetts Institute of Technology
    Despite the development of many quadrupedal robots and variety of possible running gaits, relatively little is known on the mechanisms that interplay between gait patterns and efficiency of quadrupedal machines. To gain insight on the energetics of robotic running, this work presents a study of the energetic trends across variations in gait and explores the mechanisms that are responsible for running efficiency for a quadrupedal robot. Motivated by the MIT Cheetah, the study uses a prototypical quadruped model, where DC motors are the main means of actuation, to extract principles for future control and design. This represents the first such...

  10. Dynamic exoskeleton : design and analysis of a human exoskeleton to enhance maximum dynamic performance

    Farid, Michael S
    Most existing research in powered human exoskeletons aims to increase load bearing capability or reduce the metabolic cost of walking. Current exoskeletons are typically bulky and heavy and thus impede the motion of the user. Therefore, they are not suitable for highly dynamic motions. This thesis describes the first attempt to develop a powered exoskeleton suit that improves the maximum dynamic capability of a human. This Dynamic Exoskeleton is intended to enable to the user to run faster, jump higher, or traverse challenging terrain. This thesis presents a study on improving human vertical jump height using a powered exoskeleton. A...

  11. Mitigation of losses from hydrodynamic mixing in a hydrogen bromine Laminar flow battery

    Gilson, Laura (Laura Marie)
    The hydrogen bromine laminar flow battery is a promising technology for grid-scale energy storage. It dispenses with the expensive membrane used in traditional flow batteries, instead using laminar flow to maintain the separation of fluid streams. It also takes advantage of powerful, inexpensive chemical reactants. However, mixing between the fluid streams within the battery reduces its single-pass performance and cyclability. Conditions at the inlet junction where oxidant and electrolyte streams come together are thought to influence mixing. This work investigates the relationship between fluid flow at the inlet junction, mixing, and battery performance. Matching electrolyte- and oxidant-stream flow rates or...

  12. Towards the improved robustness of acoustic cooperative localization

    Maragh, Janille M
    In this thesis, the relationship between packet loss and the accuracy of an autonomous surface craft's trajectory estimate is explored. In experimental conditions, it is common to lose subframes of acoustic packets, or even entire packets during transmission. Since packets are often used to encode localization information of and range measurements to the sender, lost packets result in poorer navigation of the receiving vehicle. Trajectory estimates, computed using nonlinear least squares optimization, are computed for a variety of client node/server code configurations, and for a series of packet transmission success rates in one of those configurations. Though it is possible...

  13. Rotation of a slender rod injected into a cylindrical constraint

    Mulcahy, Connor Gordon
    We investigate the buckling of a slender elastic rod injected into a cylindrical constraint while undergoing axial rotation. Particular focus is given to extension of the helical buckling length. This problem is of particular application to coiled tubing operations in the oil and gas industry where helical buckling and eventual lockup occur, thereby preventing complete access to horizontal oil wells. Our approach focuses on using desktop experiments to perform a precise exploration of the parameters affecting buckling. We examine two separate modes of axial rotation: continuous rotation and oscillatory rotation. In each case, we demonstrate potential for significant increases in...

  14. Computational photography with novel camera sensors

    Zhao, Hang, S.M. Massachusetts Institute of Technology
    In this thesis, two computational camera designs are presented. They target two major goals in computational photography. high dynamic range (HDR) imaging and image superresolution (SR). HDR imaging refers to capturing both bright and dark details in the scenes simultaneously. A modulo camera does not get saturated during exposure, enabling HDR photography in a single shot without losing spatial resolutions. The second camera achieves image super-resolution with its non-conventional pixel design. It is shown that recording multiple images with a sensor of asymmetric sub-pixel layout increases the spatial sampling capability compared to a conventional sensor. Both proposed camera designs are...

  15. Improving Indian beehives and beekeeping

    Abbott, Jonathan E.
    This thesis explores five beekeeping topics from a mechanical engineering perspective with findings that are relevant for both Indian and American beekeepers. First, hive weight scale mechanisms are quantitatively analyzed, yielding design improvements to improve accuracy. Second, designs of hive entrances are tested to promote traffic flow, assist ventilation, and exclude pests. Third, recommendations for Indian hive roofs and exteriors are given to keep hives cooler. Fourth, methods to bolster Indian hive standardization and manufacturing quality are suggested to promote larger, more productive colonies. Fifth, designs of hive management tools are prototyped to help encourage scientific beekeeping. This thesis concludes...

  16. Parallel pulsed jets for precise underwater propulsion

    Athanassiadis, Athanasios G
    A significant limitation for underwater robots is their ability to maneuver in tight spaces or for complex tracking tasks. Next generation vehicles require thrusters that can overcome this problem and efficiently provide high maneuverability at low speeds. Recently, thruster design has begun to draw inspiration from nature's swimmers, applying the principles of pulsed jet propulsion to robotic thrusters. Although most developments have focused on single jet actuators, nature provides some indications that multi-jet systems can provide propulsive benefits -- marine invertebrates called sales connect into chains of individual animals that each eject short jets to collaboratively move the entire chain...

  17. Numerically generating topology of the liner finish in internal combustion engines

    Wang, Renze, S.M. Massachusetts Institute of Technology
    Internal combustion (IC) engines are broadly utilized today. The friction caused by piston rings in IC engines contributes around 20% of the mechanical friction losses. The liner finish is the most critical parameter to define the tension and other design parameters of the piston rings for proper sealing. This work is focused on developing numerical approaches to generating liner finishes based on certain values of topology parameters. The generated surface is able to simulate the lubrication and dry contact behaviors of the original surface, so that the method is used to study the effects of various topology parameters on friction...

  18. Light source selection and optical design of a UV absorption based detector for liquid chromatography

    Gillund, Daniel P
    Traditional sources of UVC light for absorption spectroscopy are bulky, inefficient, and output tens to hundreds of watts of heat. In this paper we present the relative merits and disadvantages of using AIN based UVC emitting LEDs for absorption detection in liquid chromatography systems compared to traditional sources. We present the optical design for a detector based on a modular LED architecture and employing a digital micromirror device to modulate the light used in detection. The expected capabilities of a detector employing the design are derived and then compared to existing UV absorption detectors for liquid chromatography. The strategy presented...

  19. Mechanical design of optics bench for UV-LED based liquid chromatography detector

    Prasad, Aditya Shankar
    The proposal for a new detector for liquid chromatography instruments that uses Ultraviolet Light Emitting Diodes (UV-LEDs) as the light source as opposed to currently used deuterium lamps required new design of the mechanical and structural components associated with it. The optics bench assembly is the heart of the detector system on which the detector optical components are mounted. The focus of this thesis is the mechanical design of the optics bench assembly of the UV-LED detector. The thesis first briefly describes the technology and operational theory of the new detector and then discusses the considerations when designing the optics...

  20. Development of a product architecture for a LED based detector for liquid chromatography

    Saxena, Saksham
    This thesis develops and describes the product architecture for a LED based detector for liquid chromatography systems. The product architecture development is discussed using a customized methodology, incorporating elements from different views on product architecture development. The market scope and segmentation for such a device was studied and the effect of technologies for such a device on the product architecture was reviewed. The architecture of the product is described at 2 different levels. The first level is the concept design phase which links functional elements to physical components. The second level contains the grouping of components into sub-systems of the...

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