Página 1 dos resultados de 10790 itens digitais encontrados em 0.016 segundos

Electrical and thermal modulation of protein synthesis in cartilage : a model for field effects on biological tissues

MacGinitie, Laura A
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 281 leaves; 15420994 bytes; 15458203 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.16%
by Laura A. MacGinitie.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1988.; Title as it appears in M.I.T. Graduate List, Feb. 1988: Electrical and thermal modulation of protein synthesis in cartilage--a model for electric field effects on biological tissues.; Bibliography: leaves 264-281.

Low power-electrical isolation for EKG monitoring equipment

Turkel, David Howard
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: [1], 40 leaves; 3259144 bytes; 3258906 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.17%
by David Howard Turkel.; Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Includes bibliographical references.

The electrical and optical characterization of the InGaAs/InP alloy system

Towe, Elias D
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 1, iv, 79 leaves; 3782451 bytes; 3782212 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.17%
by Elias D. Towe.; Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Includes bibliographical references.

On steady-state load feasibility in an electrical power network

Dersin, Pierre
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 2, iv, 362 leaves; 18901134 bytes; 18900882 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.17%
by Pierre Dersin.; Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1980.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Vita.; Includes bibliographical references.

Electrical and mechanical mechanisms for color variation in the spraying of metallic paints

Inkpen, Stuart
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 273 [i.e. 272] leaves; 11045450 bytes; 11045209 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.17%
by Stuart Inkpen.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING; Includes bibliographies.

Investigation of current flow in the inner ear during electrical stimulation of intracochlear electrodes

Girzon, Gary
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 193 leaves; 13679766 bytes; 13679521 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.17%
by Gary Girzon.; Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING; Bibliography: leaves 189-193.

Modelling the somatic electrical response of hippocampal pyramidal neurons

Borg-Graham, Lyle J
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: [1], 295 [i.e., 296] leaves; 14631364 bytes; 14671039 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.17%
by Lyle J. Borg-Graham.; Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.; Bibliography: leaves 291-295.

Design and implementation of software to automate reuse in component-based system engineering; Software to automate reuse in component-based system engineering

Chan, Chibong
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 62 leaves; 3449977 bytes; 3451780 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.19%
The goal of this thesis is to develop software under the SpecTRM software package for the partial automation of tasks associated with reusing SpecTRM-RL component models. The automation software is designed to aid the application of component-based system engineering in SpecTRM, mainly by reducing the amount of manual work necessary in setting up component models for simulation. My thesis will examine the properties of component models, and the common tasks associated with component-based system engineering, so as to identify areas where automation is possible, and then present the user interfaces and algorithms necessary to achieve automation. The automation software will be implemented in Java under the Eclipse platform, in order to be seamlessly integrated into the SpecTRM software package.; by Chibong Chan.; Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.; Includes bibliographical references (leaf 45).

An optical-electrical sub-sampling down-conversion receiver with continuous-time [Sigma] [Delta] modulation

Park, Matthew (Matthew J.)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 89 p.; 3414261 bytes; 3417910 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.21%
This thesis describes the design and implementation of an optical-electrical sub-sampling down-conversion receiver that employs [Sigma] [Delta] modulation. Accurate sub-sampling of an electrical RF signal in the optical domain is achieved by using a low-jitter mode-locked-laser and a high-bandwidth interferometer. The sub-sampled information is then digitized by an optical-electrical continuous-time (CT) [Sigma] [Delta] analog- to-digital converter (ADC). Here, photodiodes and low-jitter pulses from the mode- locked-laser are leveraged to perform signal clocking and quantizer pre-amplification, overcoming digital-to-analog converter (DAC) clock jitter and quantizer metastability issues that plague traditional electronic implementations. The optical-electrical converter achieves 76.5 dB of SNR (12.4 ENOB) with a 1 MHz signal bandwidth and a sampling rate of 780 MHz. The chip was implemented using a standard bulk 0.18 [mu]m CMOS process from National Semiconductor, occupies a total area of 3 mm2, and consumes 45 mW of power.; by Matthew Park.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.; In title on t.p., [Sigma] and [Delta] appear as the upper-case Greek letters.; Includes bibliographical references (p. 87-89).

Physical modeling of electrical conduction in printed circuit board insulation

Sarathy, Vasanth
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 301 p.; 14003469 bytes; 14024327 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.2%
This thesis is concerned with understanding the degradation of electrical and electronic components in automobiles due to environmental effects. A special emphasis is placed on understanding the physical processes underlying the degradation, so that accelerated reliability tests can be specified with increased confidence of their validity. As a first case,printed circuit board (PCB) insulation was selected as a target for investigation. With an increase in the electronics and circuit miniaturization coupled with an increase in voltage in 42 volt as well as hybrid vehicles, PCB reliability has become an important issue. We first provide a broad presentation of insulation degradation theory as well as electrical conduction theory according to existing literature and then narrow our focus towards printed circuit board insulation. We develop a novel first-order mathematical model to describe electrical currents in printed circuit board insulation as a function of temperature, relative humidity, absorbed moisture content, voltage and geometrical characteristics. This model was developed from a series of experiments that were carefully performed under controlled laboratory conditions. In addition to describing the experimental procedure and results...

Electrical degradation mechanisms of RF power GaAs PHEMTs

Villanueva, Anita A. (Anita Ariel), 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 163 p.
ENG
Relevância na Pesquisa
76.22%
GaAs Pseudomorphic High-Electron Mobility Transistors (PHEMTs) are widely used in RF power applications. Since these devices typically operate at high power levels and under high voltage biasing, their electrical reliability is of serious concern. Previous studies have identified several distinct degradation phenomena in these devices, but a complete picture has yet to be formed. In this study, we have carried out a comprehensive study of the mechanisms of electrical degradation on a set of experimental RF power GaAs PHEMTs (non-commercial devices provided by our sponsor, Mitsubishi Electric). A wide variety of electrical stressing experiments employing different conditions (varying temperature, bias, environment) were performed on these devices in order to monitor their degradation with stressing. Our general observations showed several forms of degradation, the most concerning being an increase in the drain resistance RD and a reduction in maximum drain current Imax. Contrary to what is often claimed in the literature, our experiments indicated that these forms of degradation were not driven by impact-ionization or hot-electron effects. Instead, we found the degradation to be strongly correlated with temperature, stressing environment...

ELVIS iLab : a flexible platform for online laboratory experiments in electrical engineering; Flexible platform for online laboratory experiments in electrical engineering

Gikandi, Samuel
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 83 leaves
ENG
Relevância na Pesquisa
86.27%
This thesis describes a project that is part of the collaboration between MIT and universities in sub-Sahara Africa to exploit the value of iLabs in the developing world. The main goal of this project is to develop software that will exploit the value of the National Instruments Educational Laboratory Virtual Instrumentation Suite (ELVIS) system in Africa by integrating it into the iLabs shared architecture, while taking into consideration the special circumstances surrounding the deployment of iLabs in Africa such as bandwidth limitations, limited access to networked computers and lack of computer skills on the part of students. Integrating ELVIS into iLabs will facilitate the rapid deployment of new online labs to augment the Physics and Electrical engineering curricula in these universities. iLab development efforts for this project are being done in parallel with developers at the Obafemi Awolowo University (OAU) in Nigeria. One of the main goals of the new system is to fill the gap of laboratory experiences in introductory level electronics and physics classes, which are hardest hit by the lack of equipment due to their typically large enrollment. Our goal is to support the development of electronic circuit building skills by providing an environment where students can easily try different circuit configurations before submitting experiments for execution. We are therefore investigating new iLab client user interface designs that will enable students to create and edit circuit schematics from provided electronic components. Our ELVIS iLab design will also formalize and simplify the process of creating and administering such labs for instructors...

Hydrogel cell encapsulation for tissue engineering

Ling, Yibo
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 124 leaves
ENG
Relevância na Pesquisa
76.19%
The engineering of artificial tissues for restoration or replacement of organ function holds the potential to alter the landscape of medical therapeutics. In many tissue engineering approaches, cells seeded within 3D porous structures are expected to remodel into tissue-like structures. Despite significant progress, difficulties in lack of control over tissue architecture as well as vascularization continue to limit the efficacy of engineered constructs. This thesis describes work aimed at tackling these two problems. First, two techniques for generating size- and shape-controlled cell-laden hydrogels are described in the context of potential modular assembly for conferring greater control over the geometry of homotypic and heterotypic cell arrangements within engineered tissues. Then, a method for producing cell-loaded microfluidic agarose hydrogels for tissue engineering is described.; by Yibo Ling.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.; Vita.; Includes bibliographical references (leaves 116-123).

Nanostructured Origami (TM) : stress-engineering of nanopatterned membranes to produce three-dimensional structures; Stress-engineering of nanopatterned membranes to produce three-dimensional structures

Arora, William Jay
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 127 p.
ENG
Relevância na Pesquisa
76.2%
Microdevice fabrication is done on the surface of polished flat semiconductor substrates with a series of material depositions, etches and lithography steps. These processes are inherently planar and well suited for the fabrication of billions of micrometer-thick transistors over 300 mm diameter substrates, but impractical for building vertically. This thesis presents a method of building three-dimensionally (3D) with existing planar fabrication technology: fabricate on a thin membrane, and then fold the membrane into a 3D structure. Material stresses patterned on a membrane will cause controlled bending. A simple demonstration is the bilayer, in which a stressed metal is deposited on a stress-free membrane. One challenge with this approach is to achieve very small fold radii for tight 3D packing. The solution presented here is helium ion implantation into the membrane, which creates a large localized stress that is capable of bending a 100 nm thick membrane around a 1 [mu]m radius without fracturing it. The energy and dose of the helium ions control the direction and angle of the fold, which is explained within a theoretical framework, and shown to agree with experiment. One application of stress-folding is a chemical sensor. Built as a 3D micro-switch...

A reconfigurable electrode array for use in rotational electrical impedance myography

Scharfstein, Michael
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 72 p.
ENG
Relevância na Pesquisa
76.18%
This thesis describes the design of a novel handheld electrode probe and measurement system for use in rotational electrical impedance myography (EIM), which is a method for diagnosing neuromuscular disease. The probe can be controlled from a PC via USB and uses an array of small electrode cells that can be connected together into larger electrodes with the help of crosspoint switches. A measurement system capable of fast multifrequency impedance measurement has also been developed. The two systems have performed well, with measurements being very close to those achieved by more traditional electrical impedance myography methods.; by Michael Scharfstein.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Includes bibliographical references (p. 71-72).

Modular development of an educational remote laboratory platform for electrical engineering : the ELVIS iLab; ELVIS iLab

Jiwaji, Adnaan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 76 p.
ENG
Relevância na Pesquisa
86.17%
iLabs are remote online laboratories that allow users to perform experiments through the Internet. As an educational tool the iLab platform enables students and educators, who do not have access to laboratories, to complement their theoretical knowledge by carrying out experiments remotely on equipment located anywhere in the world and at any time of the day. Students perform experiments on actual instruments allowing them to get real data, instead of relying on simulations. The iLab project has been deployed in 3 universities in Africa using the National Instruments Educational Laboratory Virtual Instrument Suite platform which is a cheap all-in-one electronics workstation for electronics experiments. This thesis describes an increase in the functionality available on the current version of the ELVIS iLab in order to enable a wider range of experiments to be run on the platform. The functionalities explored include adding two arbitrary waveform generator channels and bode analyzer for frequency domain analysis, which was not possible in the previous designs.; by Adnaan Jiwaji.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.; Includes bibliographical references (p. 75-76).

Collagen and hyaluronic acid interpenetrating polymer networks for tissue engineering; Collagen and hyaluronic acid IPNs for tissue engineering

Brigham, Mark D
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 70 leaves
ENG
Relevância na Pesquisa
76.17%
Interpenetrating Polymer Networks (IPNs) represent a strategy for combining the properties of several polymeric materials into a single network. In this thesis, collagen and methacrylated hyaluronic acid are combined in IPNs to produce a range of new biocompatible. The fabrication method allows for control of compressive strength of the IPN hydrogels. The materials are confirmed to be homogeneous at microscopic scales with fluorescent techniques. The IPNs are used for cell encapsulation and have the potential to be used for surface cell culture. The mechanical properties can be adjusted to match those of cardiac tissue. Thus, when combined with the properties of biocompatibility, viable cell encapsulation, and cell culture, the collagenMeHA IPN hydrogels represent a powerful new material for tissue engineering applications.; by Mark D. Brigham.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.; Includes bibliographical references (leaves 68-70).

Biomimetic electrical stimulation for cardiac tissue engineering

Tandon, Nina
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 75 leaves
ENG
Relevância na Pesquisa
76.31%
A major challenge of tissue engineering is directing cells to establish the physiological structure and function of the tissue being replaced. Electrical stimulation has been used to induce synchronous contractions of cultured cardiac constructs. The hypothesis adopted for this study is that functional cardiac constructs can be engineered by "mimicking" the conditions present during cardiac development, and in particular, electrical stimulation using supra-threshold signals. For this Master's Thesis research, I have compared the material properties and charge-transfer characteristics at the electrode-electrolyte interface of various biocompatible materials, including carbon, stainless steel, titanium and titanium nitride, for use as electrodes in a biomimetic system for cardiac tissue engineering. I have also designed and implemented an electrical stimulator which is capable of modulating several important parameters of electrical stimulation, including stimulus amplitude and frequency.; (cont.) In addition, I have built an experimental setup incorporating this electrical stimulator and used it for experiments with C2C12 mouse myoblast cells and neonatal rat cardiomyocytes. Lastly, I have analyzed cell morphology as well as functional performance of engineered tissue by assessing excitation thresholds and maximum capture rates.; by Nina Tandon.; Thesis (S.M.)--Massachusetts Institute of Technology...

The Women's Technology Program : EECS outreach for high school students; WTP : electrical engineering and computer science outreach for high school students

Ricket, Douglas J. (Douglas James), 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 53 leaves; 608271 bytes; 608026 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
86.17%
by Douglas J. Ricket.; Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.; Includes bibliographical references (leaves 47-48).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.

Intelligence by design : principles of modularity and coordination for engineering complex adaptive agents

Bryson, Joanna Joy, 1965-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 338 p.; 27329196 bytes; 27328955 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
76.19%
All intelligence relies on search - for example, the search for an intelligent agent's next action. Search is only likely to succeed in resource-bounded agents if they have already been biased towards finding the right answer. In artificial agents, the primary source of bias is engineering. This dissertation describes an approach, Behavior-Oriented Design (BOD) for engineering complex agents. A complex agent is one that must arbitrate between potentially conflicting goals or behaviors. Behavior-oriented design builds on work in behavior-based and hybrid architectures for agents, and the object oriented approach to software engineering. The primary contributions of this dissertation are: 1. The BOD architecture: a modular architecture with each module providing specialized representations to facilitate learning. This includes one pre-specified module and representation for action selection or behavior arbitration. The specialized representation underlying BOD action selection is Parallel-rooted, Ordered, Slip-stack Hierarchical (POSH) reactive plans. 2. The BOD development process: an iterative process that alternately scales the agent's capabilities then optimizes the agent for simplicity, exploiting tradeoffs between the component representations. This ongoing process for controlling complexity not only provides bias for the behaving agent...