Página 4 dos resultados de 10406 itens digitais encontrados em 0.017 segundos

‣ A theory of quantitative inference for artifact sets, applied to a mechanical design compiler

Ward, Allen Corlies
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 139, [2] leaves; 8835873 bytes; 8835627 bytes; application/pdf; application/pdf
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by Allen Corlies Ward.; Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1989.; Includes bibliographical references (leaves 133-138).

‣ A study of the mechanical behavior of particle filled elastomers

Montalvo, Lizabeth A. (Lizabeth Ann), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 60 leaves; 2601236 bytes; 2600997 bytes; application/pdf; application/pdf
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by Lizabeth A. Montalvo.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.; Includes bibliographical references (leaf 60).

‣ Analysis, design, fabrication, and testing of a MEMS switch for power applications; Analysis, design, fabrication, and testing of a micro-electro-mechanical systems switch for power applications

Wong, Jo-Ey, 1968-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 218 p.; 15836099 bytes; 15835858 bytes; application/pdf; application/pdf
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by Jo-Ey Wong.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.; Includes bibliographical references (p. 215-218).

‣ Frequency response of human skin in vivo to mechanical stimulation

Diller, Timothy Thomas, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 85 p.; 5198172 bytes; 5197931 bytes; application/pdf; application/pdf
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by Timothy Thomas Diller.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.; Includes bibliographical references (p. 49-51).

‣ Use of a piezoelectric actuator to study the mechanical oscillatory behavior of living cells

Yu, Jack, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 78 leaves; 3695659 bytes; 3695422 bytes; application/pdf; application/pdf
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by Jack Yu.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.; Includes bibliographical references (leaves 33-34).

‣ Optical endpoint detection for the chemical mechanical polishing process

Nam, Jamie (Jamie Hyun), 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 93 leaves; 5503473 bytes; 5503234 bytes; application/pdf; application/pdf
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by Jamie Nam.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.; Includes bibliographical references (leaves 92-95).

‣ Effects of mechanical coupling on oscillator frequency in a micromechanical accelerometer

Meredith, Kara Susanne, 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 76 p.; 2559356 bytes; 2567428 bytes; application/pdf; application/pdf
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by Kara Susanne Meredith.; Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.; Includes bibliographical references (p. 75-76).

‣ Mechanical testing of solid materials at the micro-scale

Gudlavalleti, Sauri, 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 227 p.; 9431032 bytes; 9430839 bytes; application/pdf; application/pdf
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by Sauri Gudlavalleti.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.; Includes bibliographical references (p. 145-149).

‣ Micro-opto-mechanical switching and tuning for integrated optical systems

Nielson, Gregory Nolan, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 260 p.; 12903540 bytes; 12938207 bytes; application/pdf; application/pdf
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Integrated optical circuits have the potential to lower manufacturing and operating costs and enhance the functionality of optical systems in a manner similar to what has been achieved by integrating electronic circuits. One of the basic optical elements required to enable integrated optical circuits is an integrated optical switch, analogous to transistor switches used in integrated electronic circuits. An ideal switch for integrated optical circuits would provide wavelength-selective switching. Wavelength- selective behavior is an important characteristic for devices intended for networking applications as wavelength division multiplexing (WDM) of optical signals has become the accepted standard. A major contribution of this thesis is the design, fabrication, and experimental demonstration of a wavelength-selective, integrated optical switch. This switch operates by combining a microring resonator filter with a microelectromechanical system (MEMS) device that allows the normally static ring resonator filter to be switched on and off. This represents the first demonstration of a wavelength-selective integrated optical MEMS switch. Additional contributions of this work include a new study of dielectric charging, analysis of the use of titanium nitride as structural material for MEMS...

‣ Mechanical design of a simple bipedal robot

Fong, Ming-fai
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 55 leaves; 2396396 bytes; 2397740 bytes; application/pdf; application/pdf
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The thesis objective was to design a walking robot appropriate for testing a machine earning control system. As a robot that would learn how to walk, it was pre-maturely named Toddler. The passive dynamic walker, a class of simple robots driven by gravity and inertia, was selected as the model for the Toddler robot. Two preliminary passive walkers were explored: a three-dimensional, toy-like biped with one degree of freedom at the hip; and a two-dimensional, four-legged kneed walker with degrees of freedom at the hip and knees. Bench level and computer modeled analyses were conducted during the design and construction of these robots. The simpler, toy-like walker was selected as the unactuated model for actuated Toddler. Two degrees of freedom, controlling step size and frequency, were introduced at the ankle. Toddler was able to walk with a dynamically-stable gait either passively down a ramp, or actively on a flat or slightly uphill surface. With its simple design and robust performance, Toddler provides an excellent platform for testing machine learning control in walking robotics.; by Ming-fai Fong.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.; Includes bibliographical references (leaf 55).

‣ Mechanical, sensor and control system design for an accelerometer calibrator with one part per million accuracy

Damazo, Bradley Nevins
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 160 leaves; 6528600 bytes; 6528409 bytes; application/pdf; application/pdf
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by Bradley Nevins Damazo.; Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1988.; Bibliography: leaves 129-132.

‣ Micro/nanoscale modeling of anisotropic mechanical properties of polymer/layered-silicate nanocomposites

Sheng, Nuo, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 125 leaves; 22137256 bytes; 22139257 bytes; application/pdf; application/pdf
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by Nuo Sheng.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002.; Includes bibliographical references (leaves 123-125).

‣ A continuum constitutive model for the mechanical behavior of woven fabrics including slip and failure

King, Michael J. (Michael James), 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 315, [9] p.
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Woven fabrics are used in many applications, including ballistic armors and fabric-reinforced composites. Advances in small-scale technologies are enabling new applications including fabrics with embedded electronics, active yam materials, or microfluidics. In order to facilitate the design and improvement of such applications, we propose a modeling approach that relates the macroscopic response of the fabric to the behavior of the underlying yarns and weave. The resulting continuum model is more computationally efficient than a discrete model that represents every yam or fiber explicitly. Because it is physically based on the fabric mesostructure, the model can be used to predict the behavior of novel fabric designs. It can be easily tailored to a wide variety of different applications through the choice of suitable, physically motivated constitutive behaviors for the components that make up the assumed underlying mesostructure. We first describe a model suitable for slip-free planar deformations of a plain weave Kevlar® fabric in response to in-plane loads. We next extend this model to three dimensional behaviors through the development of an anisotropic shell implementation that includes the resistance of the fabric to bending and twist.; (cont.) The model predictions are validated against a number of experimental investigations. Yam friction and yam pullout experiments are used to study the phenomenon of yam slip and to characterize the frictional forces that oppose it. We propose a novel approach for capturing slip in a continuum fabric model...

‣ Implementation of mechanical, electrical, and feedback control systems in unmanned aerial vehicles

Tan, Derrick (Derrick Chi-Ho)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 53 leaves
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The thesis objective was to design an unmanned aerial vehicle that was capable of stable, autonomous flight. A fixed wing aircraft was chosen to simplify some of the flight characteristics and avoid some of the challenges found in rotary wing machines. Two aircraft were tested: a large and heavy gasoline powered aircraft and a smaller and much lighter electric powered sailplane. An autopilot was implemented into both platforms that would fly the aircraft and allow the measurement of flight vehicle characteristics. A link with the vehicle was created by installing a radio modem that allowed communication between the autopilot and a ground computer. This allowed updates to the controllers PID feedback loops to change flight characteristics and made the recording of flight parameters possible. This would be useful later in the analysis of data. To control the vehicle remotely, a ground computer was used that ran systems monitoring software. It also allowed the programming of flight plans to the autopilot. Combining these systems together proved successful and stable flight was achieved in both aircraft. By using the same autopilot in both vehicles, it was proven that the electronic system could be modular and transplanted between various vehicles.; by Derrick Tan.; Thesis (S.B.)--Massachusetts Institute of Technology...

‣ Mechanical design of a contra-rotating propeller assembly for a small underwater ROV

Stefanov-Wagner, Thaddeus (Thaddeus J.)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 40 leaves
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A project was undertaken to design and build a contra-rotating propeller assembly for a small underwater remotely operated vehicle (ROV), with the intent of commissioning a production run at a later time. The desired production rate was greater than one assembly per seven hour day with one machinist, at a material cost of less than $600 per assembly. Lastly, the design had to be compatible with the propeller design work being done concurrently by J. Stanway. The specified goals were met. The material cost of each assembly was $496.02 at the time of manufacture. In the production run, the incremental time for making each assembly was under 5 hours, giving a large margin for overhead and work interruptions.; by Thaddeus Stefanov-Wagner.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.; Includes bibliographical references (leaf 29).

‣ Face-up chemical mechanical polishing : kinematics and material removal rate; Face-up CMP : kinematics and material removal rate

Shieh, Marvin Bryan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 27 leaves
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A working prototype face-up CMP tool has successfully been completed. Experiments conducted on the face-up CMP machine qualitatively correspond with the theoretical polishing model. Discrepancies in data from the theoretical model could potentially be caused by non-uniform loading of the polishing pad and uneven distribution of slurry over the pad due to the edge effects on fluid flow. Despite the discrepancies, experimental data suggest that the theoretical model used to describe blanket wafer polishing by the face-up CMP tool is at least partially valid.; by Marvin Bryan Shieh.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.; Includes bibliographical references (leaf 27).

‣ Portable sensor to measure the mechanical compliance transfer function of a material

Post, Ethan A. (Ethan Adam)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 49 leaves
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A device that can measure the dynamic compliance of a material has applications for research, health sciences and for use as a pedagogical tool. A device was created which stochastically perturbs a material while measuring the resulting forces and displacements. A software program then creates a non-parameterized impulse response function in addition to a fit second order model for the material. The device was tested on a compliant sponge sample which exhibited highly nonlinear dynamic behavior. The low frequency compliance of the sponge was measured with the device with 16% to 31% error. Improvements for further dynamic testing on the sponge are presented as well as future improvements to the design of the device.; by Ethan A. Post.; Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.; Includes bibliographical references (leaves 35-36).

‣ The mechanical behavior of maraging steel under extreme electromechanical and thermal conditions

Raboin, Peter J
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 3 v. (389 leaves)
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by Peter J. Raboin.; Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1989.; Includes bibliographical references.

‣ Mechanical behavior of ultrastructural biocomposites

Kearney, Cathal (Cathal John)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 163 leaves
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For numerous centuries nature has successfully developed biocomposite materials with detailed multiscale architectures to provide a material stiffness, strength and toughness. One such example is nacre, which is found in the shells of many mollusks, and consists of an inorganic phase of aragonite tablets 5-8jim in planar dimension and 0.5-1gm in thickness direction and an organic phase of biomacromolecules. High resolution microscopy imaging was employed to investigate the microscale features of seashell nacre to reveal the nucleation points within tablets, the sector boundaries and an overlap between tablets of neighboring layers of [approx.] 20 %. Aragonite, the mineral constituting the inorganic phase of nacre, is a calcium carbonate mineral that is ubiquitous in many natural systems, including both living organisms and geological structures. Resistance to yield is an important factor in the ability of aragonite to provide both strength and toughness to numerous biological materials. Conversely, plastic deformation of aragonite is a governing factor in the formation and flow of large scale geological structures. The technique of nanoindentation combined with in-situ tapping mode atomic force microscopy imaging was used to show the anisotropic nanoscale plastic behavior of single crystal aragonite for indentations into three mutually orthogonal planes.; (cont.) Force vs. indentation depth curves for nanoindentation coaxial to the orthorhombic crystal c-axis exhibited distinct load plateaus...

‣ Minimally invasive instrument for in vivo measurement of solid organ mechanical impedance

Ottensmeyer, Mark Peter
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 165 p.
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The medical field, and surgeons in particular, are turning to engineers to develop systems that help them learn their craft better. Mannequin-based systems, animal labs and surgery on cadavers each have drawbacks that could be addressed through realistic computer-based surgical simulation systems. To generate a simulation that includes both tactile/haptic and visual feedback, one must know what the material properties of tissue are, so that a finite element or other model can generate the proper predictions for interactions between surgical instruments and tissue. This thesis presents the design, construction, characterization, and use of a mini- mally invasive surgical instrument designed to measure the linear visco-elastic prop- erties of solid organs. The Tissue Material Property Sampling Tool, or TeMPeST 1-D, applies a small amplitude vibration normal to the surface of an organ such as liver or spleen, and records the applied force and displacement. It has a range of motion of up to lmm, and can apply up to 300mN force with a 5mm right circular indenter. The open loop bandwidth of the system is approximately 100Hz, which is greater than the bandwidth of both the human visual and motor control systems. The relationships between indentation force and displacement and material prop- erties such as the elastic modulus of tissue are presented...