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Mechanical Engineering - Master's degree

Mostrando recursos 1 - 20 de 3.685

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

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

  2. Behavior of liquid lubricants in vacuum.

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

  3. 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...

  4. 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.

  5. Modeling print time for a fused deposition modeling machine

    Xu, Yuanhan
    A feature-based time estimation model is developed to predict printing time of any given object on a fused deposition modeling machine. Preliminary experiments are conducted to detect the significant factors that cause the error between actual and estimated submission time. A proposed method models the movements and heating processes of the extruder nozzle and calculates print time using G-code. The result of the proposed model is also compared with the most downloaded print time simulator on Google Play and demonstrated that the proposed model significantly improves the estimation of print time. Recommendations for future steps to improve the accuracy of...

  6. Manufacturing and design of low cost stackable drawer for mass production

    Fu, Jody (Jody C.)
    This thesis explores a next generation storage unit design for warehouses that increases stiffness, decreases assembly time, maintains or improves gross cubic utilization (GCU) - the amount of total available space that is actually utilized by product within the unit-while minimizing costs related to onsite assembly, shipping, packaging and manufacturing. This work focuses specifically on a stackable based storage solution in which machinery could stack and unstack different totes to stow and retrieve product. This is a descriptive thesis of the engineering design process - problem and goal identification, background research, functional requirements, creative idea generation and analysis, concept selection...

  7. Development of a mobile-enabled vibration perception threshold device to screen for peripheral neuropathy

    Ong, Jessica (Jessica L.)
    A common complication of diabetes is distal symmetric polyneuropathy (DSPN), which is nerve damage that typically leads to a loss of tactile sensation in the feet and is a major cause of foot ulcers and leg amputations. A key limitation to current screening and ulcer prevention in India is the impracticality of current diagnostic equipment, which is expensive, bulky, and requires trained operators. Consequently, the majority of the Indian diabetic population in low-resource settings is currently not being tested for neuropathy. The Mobile-Enabled Diabetic Foot Analyzer (mDFA) is a portable neuropathy screening device that provides quantitative information about a diabetic...

  8. Optimization of head and duct design for a warehouse vacuum robot using computational fluid dynamics

    Maia Araujo Lima, Barbara
    This project focused on the development of a vacuum head and duct for integration into an automated robotic vacuum cleaning unit for warehouse and industrial applications. Although many autonomous cleaning robots are available on the market, very few are appropriate for industrial applications and those that are often have slow cleaning rates and bulky, impractical sizes. By computational fluid dynamics (CFD) simulations, prototyping, and testing, an improved option for such a robot was created with the capability of competing with current vacuums, a significantly smaller volume, and the ability to clean while moving at much faster speeds. The CFD was...

  9. Robotic vacuum cleaner design to mitigate slip errors in warehouses

    Schilling, Benjamin Fritz
    Warehouses are extremely dusty environments due to the concrete and cardboard dust generated. This is problematic in automated warehouses that use robots to move items from one location to another. If the robot slips, it can collide with other robots or lose track of where it is located. Currently, to reduce the amount of dust on the floor, warehouses use industrial scrubbers that users walk behind or ride. This requires manual labor and a regular scheduled maintenance plan that needs to be followed to mitigate the dust accumulation. Therefore, an industrial robotic vacuum cleaner that can continuously clean the warehouse...

  10. Prediction of velocity distribution from the statistics of pore structure in 3D porous media via high-fidelity pore-scale simulation

    AlAdwani, Mohammad S. Kh. F. Sh
    Fluid flow and particle transport through porous media are determined by the geometry of the host medium itself. Despite the fundamental importance of the velocity distribution in controlling early-time and late-time transport properties (e.g., early breakthrough and superdiffusive spreading), direct relations linking velocity distribution with the statistics of pore structure in 3D porous media have not been established yet. High velocities are controlled by the formation of channels, while low velocities are dominated by stagnation zones. Recent studies have proposed phenomenological models for the distribution of high velocities including stretched exponential and power-exponential distributions but without an underlying mechanistic or...

  11. Decentralized infrastructure for file storage

    Greco, Nicola, S.M. Massachusetts Institute of Technology
    How might we incentivize a peer-to-peer network to store users' files? The purpose of this research is to combine ideas from existing peer-to-peer file sharing systems, blockchain technology and Proofs-of-Storage to create an incentivized decentralized storage network, where every participant can earn a reward for storing and serving files or pay the network to store or retrieve their own. More broadly, in this thesis we present the elementary components for building decentralized infrastructure, culminating in a protocol for incentivizing file storage.

  12. The Traveling Salesman Problem and orienteering for kinodynamic vehicles

    Adler, Aviv
    The Traveling Salesman Problem is a major foundational problem in the fields of Computer Science, Operations Research, and Applied Mathematics, in which an agent wants to visit a set of target points with the shortest path possible. This problem is of the highest interest both theoretically in practice. When the agent is a vehicle whose trajectory must satisfy a set of dynamic constraints and the target points are distributed over a continuous space, this problem is especially relevant to robotics. Although this problem is considered computationally intractable to solve precisely, in many settings a good approximate path can be computed...

  13. Scalable design of high-performance on-chip Terahertz source and imager

    Hu, Zhi, S.M. Massachusetts Institute of Technology
    In this thesis, two chip designs using the scalable array architecture are introduced. Firstly, we introduce a scalable architecture of coherent harmonic oscillator array for high-power and collimated radiation beam at mid-THz band. The array is 2D-coupled, and each element achieves these functions: (i) maximize oscillation at fundamental frequency fo= 2 50 GHz; (ii) synchronize phase of fo and its harmonics among elements; (iii) cancel near-field radiation of fo, 2fo and 3fo, and (iv) efficiently radiate at 4fo and combine power in free space. The resultant compact design fits into the optimal radiator pitch of [lambda]/2 (half wavelength) for side-lobe...

  14. Topology hiding computation on all graphs

    LaVigne, Rio (Kristen Rio)
    A distributed computation in which nodes are connected by a partial communication graph is called topology-hiding if it does not reveal information about the graph beyond what is revealed by the output of the function. Previous results have shown that topology-hiding computation protocols exist for graphs of constant degree and logarithmic diameter in the number of nodes [Moran-Orlov-Richelson, TCC'15; Hirt et al., Crypto'16] as well as for other graph families, such as cycles, trees, and low circumference graphs [Akavia-Moran, Eurocrypt'17], but the feasibility question for general graphs was open. In this work we positively resolve the above open problem: we...

  15. Estimation of clinical trial success rates and related parameters

    Wong, Chi Heem
    Previous estimates of drug development success rates rely on relatively small samples of pharmaceutical industry-curated databases, which are subject to potential sample selection biases. Using a sample of 185,994 unique entries of clinical-trial data for over 21,143 compounds from January 1st, 2000 to October 31st, 2015, we estimate aggregate success rates and durations of clinical trials. We also compute disaggregated estimates by stratifying across several features including: disease type, clinical phase, industry/academic sponsor, biomarker presence, lead indication status, and over time. In several cases, our results differ significantly from widely cited statistics. For example, oncology has a 3.4% success rate...

  16. Terahertz beam-steering imager using a scalable 2D-coupled architecture and multi- functional heterodyne pixels

    Zhang, Guo, S.M. Massachusetts Institute of Technology
    The topic covered by this thesis is the project of designing a terahertz imager chip on nowadays commercialized mature silicon platform. In the project, we developed the design method of a multi-functional heterodyne pixel and a scalable array architecture. The pixel is a compact electromagnetic structure simultaneously performs voltage-controlled 140 GHz local oscillation, 280-GHz-signal receiving, sub-harmonic mixing, and intermediate frequency (IF) signal extraction. Each pixel consumes 10 mW power and achieves a sensitivity of 2.9 pW in simulation. The local oscillator (LO) of the pixel is phase coupled with its neighbors; the whole oscillator array is then stabilized by an...

  17. Skin friction drag reduction in turbulent flows using superhydrophobic surfaces

    Rajappan, Anoop
    The use of randomly textured superhydrophobic surfaces have recently gained interest as a potential approach for the passive reduction of skinfriction on the hull of ships, submarines and underwater projectiles. When submerged in water, these surfaces trap a layer of air (or 'plastron') within their texture, which allows the external fluid to partially slip over the boundary, decreasing the net frictional shear stress on the wall. Five prototype drag-reducing surfaces were evaluated experimentally as possible candidates for turbulent drag reduction applications, using a combination of flow tests, surface profile measurements, and contact angle goniometry. Three of these were randomly rough...

  18. Microwave response of nonlinear oscillations in resistively shunted superconducting nanowires

    Toomey, Emily
    Many superconducting technologies such as rapid single flux quantum computing (RSFQ) and superconducting quantum interference devices (SQUIDs) rely on the modulation of nonlinear dynamics in Josephson junctions for functionality. More recently, however, superconducting devices have been developed based on the switching and thermal heating of nanowires for use in fields such as single photon detection and digital logic. In this Master's thesis, I will use resistive shunting to control the nonlinear heating of a superconducting nanowire and compare the resulting dynamics to those observed in Josephson junctions. In particular, I will use a microwave drive to modulate the nonlinear behavior...

  19. Investigating social media usage patterns and privacy awareness with composite data visualization

    Yuan, Ben Z. (Ben Ze)
    This thesis describes an investigation into the degree of awareness people have of their activity and audience on social media, and into the alignment of sharing expectations with actual sharing behavior. It is previously reported that people tend to share problematic posts on social media networks because they are not always aware of who can actually see their posts and other activity and do not always apply privacy settings effectively. We built a data collection tool that gathers social media data, like posts, connections, and private messages, from Facebook, Twitter, Instagram, and LinkedIn, and assembles a composite profile combining information...

  20. Long-wave infrared frequency combs based on quantum cascade lasers

    Zeng, Tianyi
    Ever since the invention of quantum cascade laser (QCL), the performance and the flexibility in design has made it a desirable source for a wide range of applications, such as trace-chemical sensing, health monitoring, frequency metrology, noninvasive imgaing and infrared countermeasures. The LWIR region (or mid-infrared region), roughly ranging from 2-20 [mu]m, is of particular importance to spectroscopy applications, since many molecular species have their strongest rotational-vibrational absorption bands in that area. Infrared laser spectroscopy began about 40 years ago and has been using a variety of different tunable laser-based sources, particularly lead salt diodes, color center lasers, difference frequency...

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