Integrated Educational Project of Theoretical, Experimental, and Computational Analyses

This research demonstrates how to design an integrated capstone project by including theoretical, experimental and computational analyses of a truss bridge. The project mainly focused on leading students to approach engineering problems with various methods and to understand the advantages and disadvantages of each method. The students applied three methods to acquire the values of stresses and deflections of members in the given truss bridge. First, they calculated the stresses and deformations theoretically. Second, they actually conducted an experiment of the truss bridge with electronic measuring equipment. Lastly, they built two simulation models with Autodesk Inventor and Dassault Systèmes SolidWorks. From the comparisons of above three methods, students were guided to the validation of assumptions of theories.Cockrell School of Engineerin

Spectral Broadening of Radiation from Relativistic Collapsing Objects

We study light curves and the spectral broadening of the radiation emitted during the finite interval of time by a surface of a collapsing object. We study a simplified model of monochromatic radiations from a spherical surface which is assumed to be falling freely. We discuss the possible way how to infer the physical parameters, such as the mass and radii of emission, from the light curves and spectral broadenings.Comment: 4 pages, 4 figures, Typos are corrected and substantial parts of main text are rephrased for more better presentation. 1 reference is adde

Four-probe thermal and thermoelectric transport measurements of bismuth antimony telluride, silicon, and boron arsenide nanostructures

Thermal management in electronic devices has become a significant challenge because of the high power density in nanoelectronic devices. This challenge calls for a better understanding of thermal transport processes in nanostructures and devices, as well as new thermal management approaches such as high thermal conductivity materials and efficient on-chip thermoelectric coolers. While several experimental methods have been developed to investigate size-dependent thermal and thermoelectric properties, there are a number of limitations in the current experimental capability in probing nanoscale thermal and thermoelectric transport properties. Among these limitations is the difficulty in determining and eliminating the contact thermal resistance error so as to obtain the intrinsic thermal and thermoelectric properties of nanostructures. This dissertation presents an effort to develop new experimental methods for uncovering the intrinsic thermal and thermoelectric properties of nanostructures, and the applications of these methods for investigating the thermal and thermoelectric transport phenomena in three materials systems. The intrinsic thermoelectric properties of bismuth antimony telluride nanostructures, which are synthesized by two different methods, are characterized with a four-probe thermoelectric measurement method based on a suspended device. The obtained thermoelectric property reveals a transition from n-type to p-type electronic transport as the antimony to bismuth ratio is increased to about 0.25. The peak zT was found when this ratio is close to 0.5. A new four-probe thermal transport measurement method is established in this work to probe both the contact thermal resistance and intrinsic thermal resistance of a nanostructure, which can be either an electrical conductor or insulator. The effectiveness of this method is demonstrated with its use to reveal size-dependent thermal conductivity of patterned silicon nanowires. The new four-probe measurement method is employed to obtain both the intrinsic thermal and thermoelectric properties of nanostructures of boron arsenide (BAs) with potentially record high thermal conductivity. The measurement results suggest that the thermal conductivity of one of such sample with an equivalent diameter of about 1.1 μm is higher than that of bulk silicon, despite pronounced phonon scattering by surface roughness and point defects associated with arsenic vacancies. In addition, high thermoelectric power factor was measured on the BAs sample.Mechanical Engineerin

Concert recording 2022-04-20a

[Track 1]. V\u27adoro pupille ; Lascia ch\u27io pianga / Frederic Handel -- [Track 2]. Three songs of the sea. I. The sea-bird ; II. Moonlight ; III. By the sea / Roger Quilter -- [Track 3]. Clair de lune ; En priere / Gabriel Faure -- [Track 4]. Ten Blake Songs with Oboe. I. Infant Joy ; II. A Posion Tree ; III. The Piper ; IV. London ; V. The Lamb ; VI. The Shepherd ; VII. Ah! Sun-flower ; VIII. Cruelty has a Human Heart ; IX. The Divine Image ; X. Eternity / R. Vaughn Williams -- [Track 5]. Auf ein altes Bild ; Im dem Schatten meiner Locken / Hugo Wolf -- [Track 6]. Give me Jesus / Larry Schackley -- [Track 7]. Here\u27s one / Tom Fettke

Concert recording 2022-04-20a

[Track 1]. V\u27adoro pupille ; Lascia ch\u27io pianga / Frederic Handel -- [Track 2]. Three songs of the sea. I. The sea-bird ; II. Moonlight ; III. By the sea / Roger Quilter -- [Track 3]. Clair de lune ; En priere / Gabriel Faure -- [Track 4]. Ten Blake Songs with Oboe. I. Infant Joy ; II. A Posion Tree ; III. The Piper ; IV. London ; V. The Lamb ; VI. The Shepherd ; VII. Ah! Sun-flower ; VIII. Cruelty has a Human Heart ; IX. The Divine Image ; X. Eternity / R. Vaughn Williams -- [Track 5]. Auf ein altes Bild ; Im dem Schatten meiner Locken / Hugo Wolf -- [Track 6]. Give me Jesus / Larry Schackley -- [Track 7]. Here\u27s one / Tom Fettke

Spin-orbit torques from interfacial spin-orbit coupling for various interfaces

We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism provides a compact analytic expression for current-induced spin-orbit torques in terms of unperturbed scattering coefficients, allowing computation of spin-orbit torques for various contexts, by simply substituting scattering coefficients into the formulas. It applies to calculations of spin-orbit torques for magnetic bilayers with bulk magnetism, those with interface magnetism, a normal metal/ferromagnetic insulator junction, and a topological insulator/ferromagnet junction. It predicts a dampinglike component of spin-orbit torque that is distinct from any intrinsic contribution or those that arise from particular spin relaxation mechanisms. We discuss the effects of proximity-induced magnetism and insertion of an additional layer and provide formulas for in-plane current, which is induced by a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in the same formalism.Comment: 24 pages, 9 figure