Physical Sciences and Mathematics Commons^™

A New Model For The Spectral Induced Polarization Signature Of Bacterial Growth In Porous Media, Andre Revil, Estella A. Atekwana, C. Zhang, Abderrahim Jardani, Schaun M. Smith

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The complex conductivity of porous materials and colloidal suspensions comprises two components: an in-phase conductivity associated with electromigration of the charge carriers and a quadrature conductivity associated with the reversible storage of the charges at some polarization length scales. We developed a quantitative model to investigate the frequency domain induced polarization response of suspensions of bacteria and bacteria growth in porous media. Induced polarization of bacteria (α polarization) is related to the properties of the electrical double layer of the bacteria. Surface conductivity and α polarization are due to the Stern layer of counterions occurring in a brush of polymers …

Polarization Properties Of Maxwell-Gauss Laser Beams, Jessica Patricia Conry

Graduate Theses and Dissertations

Laser beams are wave-like optical disturbances. They are characterized by a dominant direction of propagation and a finite extent transverse to the direction of propagation. Many characteristics of laser beams can be described in terms of a scalar function multiplied by a constant vector, which can be real (for linear polarization) or complex (for elliptical polarization). The scalar function is a solution to the paraxial scalar wave equation. This scalar description, however, fails to describe the polarization and focusing characteristics of laser beams correctly. For a correct accounting of these characteristics, the electric and magnetic fields associated with laser beams …

H20 Maser Observations In W3 (Oh): A Comparison Of Two Epochs, Steven Merriman

College of Science and Health Theses and Dissertations

We present high resolution observations of 22 GHz H$_{2}$O masers toward the star forming region W3(OH), taken during two epochs using the Very Long Baseline Array telescope. We detected a total of 54 masers in observation BS198A, and 67 in BS198B, arranged in 3 groups. We determined that the observation BS198A took place during a period of quiescence, while BS198B was observed during a flaring period. We interpreted the maser morphology as lying on the eastern (Group 1) and western (Group 3) ends of an outflow, as well as near the outflow base (Group 2). We observed a velocity drift …

The Effect Of Polarization And Ingan Quantum Well Shape In Multiple Quantum Well Light Emitting Diode Heterostructures, Patrick M. Mcbride

Master's Theses

Previous research in InGaN/GaN light emitting diodes (LEDs) employing semi-classical drift-diffusion models has used reduced polarization constants without much physical explanantion. This paper investigates possible physical explanations for this effective polarization reduction in InGaN LEDs through the use of the simulation software SiLENSe. One major problem of current LED simulations is the assumption of perfectly discrete transitions between the quantum well (QW) and blocking layers when experiments have shown this to not be the case. The In concentration profile within InGaN multiple quantum well (MQW) devices shows much smoother and delayed transitions indicative of indium diffusion and drift during …

Microwave Optics Research, Allen Andersen, Todd Lines, Josh Barney

Allen Andersen

The BYU-Idaho Physics Department x-band microwave optics equipment was originally intended for use in classroom demonstrations. I evaluated this equipment for use in research. I designed and built additional equipment needed in order to perform attenuation and other experiments then used it to conduct research on the transmission properties of paper and other substances. The new equipment allowed me to create a standard experimental procedure, take reasonably accurate measurements, and reduce undesired standing wave effects. Mathematical and experimental analysis was done to determine the necessary parameters of the new equipment. The new apparatus is comparable to setups featured in published …

Artificially Disordered Birefringent Optical Fibers, Sumudu Herath, N. P. Puente, Elena I. Chaikina, Alexey Yamilov

Physics Faculty Research & Creative Works

We develop and experimentally verify a theory of evolution of polarization in artificially-disordered multi-mode optical fibers. Starting with a microscopic model of photo-induced index change, we obtain the first and second order statistics of the dielectric tensor in a Ge-doped fiber, where a volume disorder is intentionally inscribed via UV radiation transmitted through a diffuser. A hybrid coupled-power & coupled-mode theory is developed to describe the transient process of de-polarization of light launched into such a fiber. After certain characteristic distance, the power is predicted to be equally distributed over all co-propagating modes of the fiber regardless of their polarization. …

Polarimetric Retrievals Of Surface And Cirrus Clouds Properties In The Region Affected By The Deepwater Horizon Oil Spill, Matteo Ottaviani, Brian Cairns, Jacek Chowdhary, Bastiaan Van Diedenhoven, Kirk Knobelspiesse, Chris Hostetler, Rich Ferrare, Sharon Burton, John Hair, Michael D. Obland, Raymond Rogers

United States National Aeronautics and Space Administration: Publications

In 2010, the Goddard Institute for Space Studies (GISS) Research Scanning Polarimeter (RSP) performed several aerial surveys over the region affected by the oil spill caused by the explosion of the Deepwater Horizon offshore platform. The instrument was deployed on the NASA Langley B200 aircraft together with the High Spectral Resolution Lidar (HSRL), which provides information on the distribution of the aerosol layers beneath the aircraft, including an accurate estimate of aerosol optical depth.

This work illustrates the merits of polarization measurements in detecting variations of ocean surface properties linked to the presence of an oil slick. In particular, we …

Iterative Atmospheric Correction Scheme And The Polarization Color Of Alpine Snow, Matteo Ottaviani, Brian Cairns, Rich Ferrare, Raymond Rogers

United States National Aeronautics and Space Administration: Publications

Characterization of the Earth’s surface is crucial to remote sensing, both to map geomorphological features and because subtracting this signal is essential during retrievals of the atmospheric constituents located between the surface and the sensor. Current operational algorithms model the surface total reflectance through a weighted linear combination of a few geometry-dependent kernels, each devised to describe a particular scattering mechanism. The information content of these measurements is overwhelmed by that of instruments with polarization capabilities: proposed models in this case are based on the Fresnel reflectance of an isotropic distribution of facets. Because of its remarkable lack of spectral …