Thesis (M.S.)--Massachusetts Institute of Technology, School of Industrial Management, 1963. / Includes bibliographical references. / by Andrew Fenton Kazdin. / M.S.

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No / This paper presents a novel method to prepare stretchable conductors and pressure sensors based on the gold/polydimethylsiloxane (PDMS) system. The gold films were sputtered onto structured PDMS surfaces produced with a photolithographic surface treatment with the aim of reducing tensile strains in the gold film. Scanning electron microscopy (SEM) and atomic force microscopy analyses showed that these 3D patterns reduce cracks and delaminations in the gold film. Electrical measurements indicate that the patterns also protect the films against repeated tensile cycling, although the un-patterned samples remained conducting as well after the completion of 120 cycles. The extrapolated resistivity value of the patterned sample (4.5 × 10−5 Ωcm) compares well with previously published data. SEM micrographs indicate that the pattern features deflect the cracks and therefore toughen the gold film. However, x-ray photoelectron spectroscopy and contact angle analyses indicate that the patterning process also slightly modifies the surface chemistry. This patterning method was used to prepare capacitive strain gauges with pressure sensitivity (ΔZ/Z)/P of 0.14 kPa−1 in the sub-kPa regime. Such stretchable and potentially conformal low-pressure sensors have not been produced before and could prove advantageous for many smart fabric applications.

<p> Ceramic samples of Li2+xYxZr1-xO3 with x=0 to 0. 1, Li8+xYxZr1-xO6 with x=0 to 0.2, Li1-xYxZr1-xO2 with x=0 to 0.5 and Li1+xZrxY1-xO2+x with x=0 to 0. 3 were prepared via conventional solid reactions. The solubilities, crystal structures and microstructures in these samples were studied by x-ray diffraction(XRD), infrared spectra, differential thermal analysis(DTA) and scanning electron microscopy(SEM). The results show that the solubilities are 0.05≤X<0.1 for Li2+xYxZr1-xO3 and Li8+xYxZr1-xO6, 0.1≤x<0.15 for Li1-xYxZr1-xO2, and x≥0.3 for Li1+xZrxY1-xO2+x, respectively. The crystal structures of the solid solutions of Li2+xYxZr1-xO3 and Li8+xYxZr1-xO6 are the same as Li2ZrO3 and Li8ZrO6, respectively but the cell constants change slightly with x, while the structure of Li1-xYxZr1-xO2 and Li1+xZrxY1-xO2+x changes from monoclinic for pure LiYO2 (x=0) to tetragonal (x≥0.005). The sinterability of Li2ZrO3 improves greatly with yttrium additions to Li2ZrO3. </p> <p> The conductivities of the samples were measured by complex impedance spectroscopy and dc polarization. The results show that lithium conductivity in Li2+xYxZr1-xO3 samples increases slightly from 3.9x10^-6 to 5.0x10^-6 S/cm at 400°C as x increases from 0 to 0.05 and the corresponding conduction activation energy decreases slightly from 0.99 to 0.92 eV. Based on the effective medium theory, the conductivity increase in the solid solution was estimated to be 3% for x=0.05 compared with pure Li2ZrO3 crystal.</p> <p>For Li8+xYxZr1-xO6 samples, a mixture of LiOH and Li2CO3, which melts at about 430°C, can be formed during the processing and measurements. The ionic conductivity depends to a large degree on the microstructure(the amount and distribution of the mixture) below 430°C. The lithium conductivity at 435°C increases from 1.0x10^-2 to 6.9x10^-2 S/cm as x increases from 0 to 0.05. The electronic contribution to total conductivity is lower than 1% below 435°C.</p> <p> The ionic conductivity in the tetragonal phase of Zr-doped LiYO2 is much lower than in pure monoclinic LiYO2. The conductivity values at 500°C are 1.3x10^-2 for pure LiYO2 and 1.2x10^-4 for Li1.3Zr0.3Y0.7O2.3. The ionic conduction activation energy in the tetragonal Zr-doped LiYO2 is much higher than pure LiYO2.</p> <p> The thermal stability and the hydrolysis tendency for Li2ZrO3, Li8ZrO6 and LiYO2 were examined by thermodynamic calculations and by experiments.</p> / Thesis / Master of Engineering (MEngr)

Microprocessor-based systems are used for a variety of applications, ranging from industrial control systems to spaceborne systems. The complex nature of tasks to be performed has led to division and distribution of work among different subsystems. A fast and reliable means of information and data transmission among these subsystems is provided by parallel communication busses. Satellite-based systems are susceptible to transient faults caused by cosmic radiation or alpha particles. In order for a system to be usable in such an environment, it must be designed to be upset tolerant. Functionality of the design must be intact in the presence of transient faults. Several standardized bus architectures have been configured to meet a given set of performance specifications. One such bus architecture called the Nubus is used as the basis for the design and development of an upset tolerant bus architecture. The modified structure is called NuFTbus for Nu Fault-Tolerant bus. Rationale for the NuFTbus specification is presented in this thesis. A design of an IC-based bus interface unit is developed. The design is specified in the VHSIC Hardware Description Language (VHDL) and VHDL tools are used to simulate the system behavior. Simulation results are presented. The VHDL circuit description is converted to a gate array layout ready For Fabrication in an appropriate radiation-hardened gate array technology. A description oF the hardware Functional testing Facilities, along with a description of a set of test procedures, is given. / Master of Science

This study investigated the effects of score study on novice conductors’ nonverbal and verbal conducting behaviors. Presented with a brief musical excerpt of which they had no prior knowledge, undergraduate conducting students (N = 11) conducted and rehearsed a live brass quartet. After an initial conducting session, participants in the experimental group (n = 6) received two individual 30-minute score study tutorials, while the control group (n = 5) received no assistance. All participants returned one week after the first conducting session to conduct and rehearse the ensemble for a second time. Brass quartet members and three experienced conductors, all whom were blind to the experimental condition, evaluated participants’ conducting in terms of eye contact, facial expression, effective gesture, ability to lead toward a musically accurate performance, knowledge of the score, and pacing. Significant differences were found between the score study and control conditions. The brass quartet members’ ratings for eye contact and knowledge of the score were higher for the participants who studied the score. I found no significant differences between conditions in the ratings given by experienced conductors. At the conclusion of the second rehearsal, brass quartet members accurately identified five of the six conductors who had received score study assistance and four of the five conductors who had not. Experienced conductors were asked to identify the order of the two videos of each conductor. They accurately identified the order of five of the six score study conductors’ videos. Identifications of participants’ videos in the control group were mostly inaccurate and reflected much disagreement among the experienced conductors. In reviews of the participants’ written and verbal responses about their experience and the comments provided by brass quartet members and experienced conductors, I noted three characteristics that distinguished those who engaged in score study from those who had not: (1) more meaningful, instrument-specific eye contact; (2) greater confidence and comfort; and (3) more effective gestures and other nonverbal behaviors in rehearsal, all of which seemed to result from a more clearly defined interpretation of the music. / text

Cette thèse étudie le passage liquide de Luttinger liquide de Fermi au moyen de l'application d'une pression hydrostatique dans le conducteur organique quasi unidimensionnel TMTSF2PF6. La dépendance en température de la résistivité le long the l'axe de moindre conductivité fait apparaître un régime haute température qui s'interpréter par des chaînes de Luttinger alors qu'au dessous de 100K le système évolue vers un régime de chaînes couplés avec une physique de type liquide de Fermi.Ce modèle est aussi confirmé par l'étude de l'effet Hall dans le même composé.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 131-136). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 131-136). Also available on the Internet.

This study investigated the relationship between selected measures of self concept as perceived by a group of choral conductors, their eye dependency on score, and the measures of expressive voice. The problems were (1) to determine the degree of perceived self concept of a selected group of choral music teachers through measures of (a) total self, (b) physical self, (c) moral-ethical self, (d) personal self, (e) family self, and (f) social self? (2) to assess eye dependency on score of the same teachers; (3) to assess the aspect of expressive voice through measures of (a) pitch levels of modulation, (b) speech flow, and (c) voice energy level; and (4) to examine the relationship between the measures of self concept, eye dependency on score and expressive voice.