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Mechanical Engineering

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Faculty Publications

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1996

Articles 1 - 6 of 6

Full-Text Articles in Engineering

Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling Nov 1996

Characterization Of Sr‐Doped Lamno3 And Lacoo3 As Cathode Materials For A Doped Lagao3 Ceramic Fuel Cell, Kevin Huang, Man Feng, John B. Goodenough, Michael Schmerling

Faculty Publications

Energy dispersive spectrometry line scan and ac impedance spectroscopy were used in this study to investigate the chemical reactions between two cathode materials, La0.84Sr0.16MnO3 (LSM), La0.5Sr0.5CoO3-δ (LSC), and the electrolyte La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM). Significant interdiffusions of Co into LSGM and Ga into LSC were found at an LSC/LSGM interface even at relatively low fabrication temperatures. In contrast, only small interdiffusions of Mn into LSGM and Ga into LSM were detected at the LSM/LSGM interface even though it was fired at 1470°C. The …

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Bounding Elastic Constants Of An Orthotropic Polycrystal Using Measurements Of The Microstructure, Brent L. Adams, M. J. Beran, T. A. Mason, Ted Olsen Sep 1996

Bounding Elastic Constants Of An Orthotropic Polycrystal Using Measurements Of The Microstructure, Brent L. Adams, M. J. Beran, T. A. Mason, Ted Olsen

Faculty Publications

We show how information about the elastic stiffness and compliance of an orthotropic polycrystal may be obtained from measurements of the statistical properties of the microstructure. We begin by discussing the statistical properties of the governing equations and the hierarchy that results when the equations are averaged. Perturbation solutions are obtained in terms of low-order statistical information. Using methods previously developed, we derive bounds for the elastic stiffnesses and compliances. A heirarchy of bounds is derived using the statistical information obtained from measurements of the microstructure. We discuss the methods used to obtain the correlation functions of the microstructure and …

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Characterization Of The Si/Sio2 Interface Formed By Remote Plasma Enhanced Chemical Vapor Deposition From Sih4/N2O With Or Without Chlorine Addition, Young-Bae Park, Xiaodong Li, Shi-Woo Rhee Jul 1996

Characterization Of The Si/Sio2 Interface Formed By Remote Plasma Enhanced Chemical Vapor Deposition From Sih4/N2O With Or Without Chlorine Addition, Young-Bae Park, Xiaodong Li, Shi-Woo Rhee

Faculty Publications

The Si/SiO2interface formed by remote plasma enhanced chemical vapor deposition (RPECVD) at low temperature with SiH4/N2O or SiH4/N2O/Cl2 was studied and compared with thermal oxidation. The interface of the CVD SiO2 without chlorine addition is rougher than that with chlorine addition. But the surface roughness of CVD SiO2 films increases with chlorine addition. The thermal oxidation induces strong interface strains, and the strains generated by the CVD SiO2 without chlorine addition are stronger and are distributed more nonuniformly than those by the chlorinated SiO2. …

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Microstructure And Deposition Rate Of Aluminum Thin Films From Chemical Vapor Deposition With Dimethylethylamine Alane, Byoung-Youp Kim, Xiaodong Li, Shi-Woo Rhee Jun 1996

Microstructure And Deposition Rate Of Aluminum Thin Films From Chemical Vapor Deposition With Dimethylethylamine Alane, Byoung-Youp Kim, Xiaodong Li, Shi-Woo Rhee

Faculty Publications

Deposition of aluminumfilm from DMEAA in the temperature range of 100–300 °C has been studied. In this temperature range, there is a maximum deposition rate at around 150 °C. The film deposited at 190 °C has elongated blocklike grain shapes, which are ∼600 nm in width and 930 nm in length. Grains in the film deposited at 150 °C showed an equiaxed structure with grain size in the range of 100–300 nm in a film with 600 nm thickness. Aluminum oxide particle inclusion was observed especially at high deposition temperature. Plausible reaction pathways of DMEAA dissociation were suggested to explain …

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Grain-Boundary Structure Effects On Intergranular Stress Corrosion Cracking Of Alloy X-750, Brent L. Adams, Ted Olsen, N. Panayotou, Y. Pan Apr 1996

Grain-Boundary Structure Effects On Intergranular Stress Corrosion Cracking Of Alloy X-750, Brent L. Adams, Ted Olsen, N. Panayotou, Y. Pan

Faculty Publications

This work was supported by the Department of Energy under Grant No. DE-FG02-88ER 45355. TO was supported by the National Science Foundation during her 1993-94 stay at the Institute for Advanced Studies (Princeton) under grant DMS-9304580. The authors wish to acknowledge helpful discussion with Carol Nichols, John Hack, Gino Palumbo, Karl Aust, and Gary Was. It is well known that the properties and behavior of grain boundaries are strongly affected by local chemistry and atomic structure. This paper focuses on the mesoscale description of grain boundary structure (i.e. the five crystallographic degrees of freedom) and correlations with intergranular stress corrosion …

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Experiments In The Coordinated Control Of An Underwater Arm/Vehicle System, Timothy W. Mclain, Stephen M. Rock, Michael J. Lee Jan 1996

Experiments In The Coordinated Control Of An Underwater Arm/Vehicle System, Timothy W. Mclain, Stephen M. Rock, Michael J. Lee

Faculty Publications

The addition of manipulators to small autonomous underwater vehicles (AUVs) can pose significant control challenges due to hydrodynamic interactions between the arm and the vehicle. Experiments conducted at the monterey Bay Aquarium Research Institute (MBARI) using the OTTER vehicle have shown that dynamical interactions between an arm and a vehicle can be very significant. For the experiments reported in this paper, a single-link "arm" was mounted on OTTER. Tests showed that for 90-degree, two-second repetitive slews of the arm, the vehicle would move as much as 18 degrees in roll and 14 degrees in yaw when no vehicle control was …

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