Recursos de colección

DSpace at MIT (104.280 recursos)

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Mechanical Engineering - Master's degree

Mostrando recursos 1 - 20 de 3.698

  1. Design of a precise, affordable braille label maker for the blind

    Johnson, Hilary Anna
    Braille labels are a simple technology that can enable people with blindness to independently identify objects and spaces in their workplaces, homes and schools. For children learning to read and write, braille labels on their toys and objects in the home and at school could catalyze learning by helping them to associate written words with physical objects. For an adult, identifying objects such as file folders, boxes, and medications is a functional skill essential in the workplace. Labels on these objects leads to an increase in daily efficiency. Yet, even though braille labels present the potential for increased independence and...

  2. Tracking and speed evaluation of cod schools in the 2014 Nordic Seas experiments

    Ben Mordechai, Mordechai, S.M. Massachusetts Institute of Technology
    Observing and tracking fish shoals over long periods enables us to understand and establish the behavior processes of fish shoals in their ecosystem and different phases of migration, spawning and feeding. In the past, researchers have observed fish shoals for days and even weeks for that purpose. However, previous studies were limited by conventional methods such as echosounders and acoustic tagging of fish, which are only able to track one or a few schools at a time with low spatial sampling. In 2014, the Ocean Acoustic Waveguide Remote Sensing system (OAWRS) was employed in the Nordic Seas for the study...

  3. eyeDNA : Tool Condition Monitoring for a desktop CNC milling machine

    Ajilo, Deborah (Deborah M.)
    Tool wear is a major obstacle to realizing full automation in metal cutting operations. In this thesis, we designed and implemented a low cost Tool Condition Monitoring (TCM) system using off-the-shelf sensors and data acquisition methods . Peripheral end milling tests were done on a low carbon steel workpiece and the spindle vibration, cutting zone temperature and spindle motor current were recorded. Features from these data sources were used to train decision tree models in MATLAB with the aim of classifying the stages of tool wear. Results showed that the feature sets fusing information from all data sources performed the...

  4. An oxygen-controlled in vitro model of the gastrointestinal human-microbiome interface

    Holcomb, Steven John
    The gastrointestinal system plays a vital role in the functioning of the human body, processing food into useable energy, controlling homeostasis, and serving as the front line of the immune system. The intestines are aided in their many functions by the gut microbiome, a collection of 100 trillion anaerobic bacteria cells that live inside the GI tract. Although they play an essential part in the organ system, they remain little-represented in in vitro gastrointestinal models because of the difficulty of replicating the anaerobic conditions of the intestines. We constructed an in vitro model capable of growing aerobic epithelial intestinal cells...

  5. High order stochastic transport and Lagrangian data assimilation

    Dutt, Arkopal
    Ocean currents transport a variety of natural (e.g. water masses, phytoplankton, zooplankton, sediments, etc.) and man-made materials (e.g. pollutants, floating debris, particulate matter, etc.). Understanding such uncertain Lagrangian transport is imperative for reducing environmental damage due to natural hazards and for allowing rigorous risk analysis and effective search and rescue. While secondary variables and trajectories have classically been used for the analyses of such transports, Lagrangian Coherent Structures (LCSs) provide a robust and objective description of the important material lines. To ensure accurate and useful Lagrangian hazard scenario predictions and prevention, the first goal of this thesis is to obtain...

  6. LNG as a transition fuel for shipping in emission control areas

    Pateras, John G
    Since the turn of the century, the reduction of the adverse effect humanity has had on the environment has been a critical factor for our survival. The maritime industry, responsible for the transportation of over 90% of global trade, generates approximately 3% of annual greenhouse emissions. This project examines ways of reducing the emissions ocean-going vessels generate whilst in port. Real power requirement data were collected from various commercial vessels (tankers, bulk carriers, and a containership) around the world. All analyses throughout this project were performed using actual data obtained from commercial vessels, as mentioned previously. Both on-board and on-shore...

  7. Electrically charged thermal energy storage systems for grid-level electricity storage

    Meroueh, Laureen
    Unlike most other commodities, electricity produced at any given time must match the electricity being consumed or the stability of the electric grid is jeopardized. Electricity demand changes throughout the day result in required generation ramp-ups that strain power plants, reduce cycle efficiency and increase CO2 emissions. This problem is exacerbated when renewable sources such as wind and solar are integrated into the grid, due to their intermittency. A change in methods of energy production globally that allows synergistic coupling of renewable and fossil fuels is needed. Currently, pumped hydroelectric and compressed air energy storage are the two most common...

  8. A device for quantitative assessment of thumb Ulnar Collateral Ligament injury

    Cervantes, Thomas Michael
    Injury to the Ulnar Collateral Ligament (UCL) of the thumb, known as "Skier's Thumb," is treated by surgical repair for complete tears, or by splinting for partial tears. Because of this radical difference in treatment options, diagnostic accuracy is critical. The primary mechanism of diagnosis is through a clinical assessment of joint integrity. This method requires a high degree of examiner skill and experience, and is inherently qualitative. Secondary diagnosis through magnetic resonance imaging (MRI) is often required to ensure accurate diagnosis. This additional testing delays the treatment and adds to the cost of care. A method to quantitatively assess...

  9. Using cold spray to package electronic implants

    Berringer, Molly A
    Due to improvements in electronics manufacturing, electronic implants keep decreasing in size and are moving towards integrated-circuit (IC) based designs. As implant electronics become significantly smaller with the use of ICs, traditional implant packaging become a limiting factor on implant miniaturization. Additionally, current packaging techniques can be expensive, and time and labor intensive. Building electronic packages can require many materials, multiple machines, and several manufacturing steps. This thesis explores cold spray as an alternative packaging method that would address the issues associated with traditional packaging. Cold spray could be used to create conformal packaging around electronic implants. Two biocompatible packaging...

  10. Geospatial cost drivers in computer-aided electrification planning : the case of Rwanda

    Drouin, Cailinn
    This body of work builds upon that of others in the Universal Access Lab at the Massachusetts Institute of Technology who have endeavored to contribute to the resolution of a complex set of global issues by exploring possible solutions to the challenges of achieving universal energy access. To this end, a technoeconomic electricity infrastructure modeling software referred to as the Reference Electrification Model, or REM, has been conceived as a tool of potential use in navigating those particular obstacles which lie at the nexus of technology and policy. This thesis explores the incorporation of topography-related cost driver information into the...

  11. Design of an ultraportable surgical enclosure for low resource environments

    Miller, Sally A
    Access to surgical care for people in remote settings and/or developing countries is limited: 30% of the world's population receives 75% of major operations [1]. In developing countries, up to a third of patients acquire a surgical site infection (SSI), which is nine times more likely than in developed countries [2]. An estimated 85,500 cases of HIV and hepatitis are contracted by obstetrical/gynecological providers every year, and 90% of those cases are the result of treating patients living in poverty. SurgiBox aims to address these issues by providing a portable, sterile operating environment for use in austere settings. Not only...

  12. Low-stress multiwire stringing and cell interconnection for thin silicon solar cells and modules

    Meyer, Luke Thomas
    In the field of silicon solar cells and modules, multiwire interconnection technologies have received significant attention due to their performance advantages over conventional buswires. Realization of these benefits has been limited due to additional complex manufacturing steps to create an "S"-style cell interconnection wherein wires are snaked between positive and negative contact areas. It is proposed that by introducing a new method of cell interconnection, multiwire interconnection will become suitable for any thickness of silicon solar cells, including thin (50 [mu]m to 100 [mu]m) cells. In this thesis, a novel multiwire interconnection technique is proposed, wherein two discrete sets of...

  13. Online communication among student design teams

    Van de Zande, Georgia D
    New technological developments are quickly changing the ways the product design community communicates in the workplace and in the classroom. Slack, an online communication software with some project management features, has become a popular communication tool among many workers and students. This thesis examines the Slack conversation conducted by 16 student product development teams in a course at MIT, 2.009: Product Engineering Processes. Following a typical product development process, teams of 17-20 students each used the online communication tool in addition to face-to-face meetings to design new products in one semester. The resulting conversations were analyzed for message count over...

  14. Policy regularized model predictive control framework for robust legged locomotion

    Bledt, Gerardo
    A novel Policy Regularized Model Predictive Control (PR-MPC) framework is developed to allow general robust legged locomotion with the MIT Cheetah quadruped robot. The full system is approximated by a simple control model that retains the key nonlinearities characteristic to legged contact dynamics while reducing the complexity of the continuous dynamics. Nominal footstep locations and feedforward forces for controlling the robot's center of mass are designed from simple physics-based heuristics for steady state legged movement. By regularizing the predictive optimization with these policies, we can exploit the known dynamics of the system to bias the controller towards the steady state...

  15. Ab initio study of electron transport in lead telluride

    Song, Qichen, S.M. Massachusetts Institute of Technology
    Last few years have witnessed significant enhancement of thermoelectric figure of merit of lead telluride (PbTe) via nanostructures. Despite the experimental progress, current understanding of the electron transport in PbTe is based on either band structure simulated using first-principles in combination with constant relaxation time approximation or empirical models, both requiring adjustable parameters obtained by fitting experimental data. This thesis aims to compute thermoelectric properties of PbTe all from first-principles. We start by discussing the formalism based on Boltzmann transport equation to calculate the electron transport properties in PbTe using first principles and identify the importance to calculate electron-phonon interaction...

  16. Public perception of alternative water sources and water usage : a case study of desalination and recycled Water facilities

    Yun, Janet H
    The importance of public acceptance within the decision-making process for large-scale, municipal water projects is widely understood and documented. In order to assess the role of public perception on the acceptance of alternative water sources, this paper broadly evaluates public preference for alternative water source and water conservation programs through a user-based approach. Choice-based conjoint analysis was utilized as a quantitative method to determine which design attributes make alternative water sources, specifically desalination and recycled water facilities, more appealing to communities. An online survey was taken by 306 respondents in California, Florida, and Texas. Respondents were analyzed on an aggregate...

  17. Design of multi-passage cooling systems for avionics applications

    Vetter, David B. (David Brian)
    by David B. Vetter.

  18. Behavior of liquid lubricants in vacuum.

    Malkin, Stephen
    Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Thesis. 1965. M.S.

  19. An investigation into the design of surface piercing super cavitating hydrofoils

    Dutton, Timothy Spaulding
    The fluid-dynamic design of hydrofoils to support marine crafts at high speeds has received growing interest in recent years. Physics involved in the design of high-speed surface-piercing hydrofoils is complex involving three different fluid phases (air, water and vapor) and complex fluid dynamic mechanisms like unsteady cavitation and ventilation and their interaction. For speeds considerably higher than the incipient cavitation speed, the hydrofoil sections need to be adapted and design to exploit cavitation instead of avoiding it. This is particularly true for surface piercing hydrofoils that in addition to cavitation are affected by ventilation from the free surface. This thesis...

  20. Stock removal rates in internal grainding [sic]: a model of the process.

    Lindsay, Richard Paul
    Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Thesis. 1966. M.S.

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