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Series

Wright State University

2012

Articles 1 - 13 of 13

Full-Text Articles in Physics

Saturation-Dependence Of Dispersion In Porous Media, B. Ghanbarian-Alavijeh, Thomas E. Skinner, Allen Hunt Dec 2012

Saturation-Dependence Of Dispersion In Porous Media, B. Ghanbarian-Alavijeh, Thomas E. Skinner, Allen Hunt

Physics Faculty Publications

In this study, we develop a saturation-dependent treatment of dispersion in porous media using concepts from critical path analysis, cluster statistics of percolation, and fractal scaling of percolation clusters. We calculate spatial solute distributions as a function of time and calculate arrival time distributions as a function of system size. Our previous results correctly predict the range of observed dispersivity values over ten orders of magnitude in experimental length scale, but that theory contains no explicit dependence on porosity or relative saturation. This omission complicates comparisons with experimental results for dispersion, which are often conducted at saturation less than 1. …

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Magnetic Nanoparticles In Hyperthermia Treatment, Gregory Kozlowski Jun 2012

Magnetic Nanoparticles In Hyperthermia Treatment, Gregory Kozlowski

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2012)

No abstract provided.

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Ac Magnetic Heating Of Superparamagnetic Fe And Co Nanoparticles, Anna Lukawska, Zafrullah Jagoo, Gregory Kozlowski, Zafer Turgut, Hiroyuki Kosai, Alexander Sheets, Tyler Bixel, Andrew Wheatley, Pavel Abdulkin, Benjamin Knappett, Thomas Houlding, Volkan Degirmenci Jun 2012

Ac Magnetic Heating Of Superparamagnetic Fe And Co Nanoparticles, Anna Lukawska, Zafrullah Jagoo, Gregory Kozlowski, Zafer Turgut, Hiroyuki Kosai, Alexander Sheets, Tyler Bixel, Andrew Wheatley, Pavel Abdulkin, Benjamin Knappett, Thomas Houlding, Volkan Degirmenci

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2012)

No abstract provided.

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Growth Of Graphene Architectures On Sic, John J. Boeckl, Weijie Lu, William C. Mitchel, Kurt G. Eyink, Howard Smith, Larry Grazulis, Gerry Landis, Said Elhamri Jun 2012

Growth Of Graphene Architectures On Sic, John J. Boeckl, Weijie Lu, William C. Mitchel, Kurt G. Eyink, Howard Smith, Larry Grazulis, Gerry Landis, Said Elhamri

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2012)

No abstract provided.

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In-Situ Engineering Of Graphene With Electrons, Mark Ruemmeli Jun 2012

In-Situ Engineering Of Graphene With Electrons, Mark Ruemmeli

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2012)

No abstract provided.

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New Routes To Copper Nanocatalysts For Fine Chemical Synthesis, Pavel Abdulkin, Yanina Moglie, Faysal Benaskar, Volker Engels, Jan Meuldijk, Volker Hessel, Emiel J. M. Hensen, Miguel Yus, Jaap C. Schouten, Francisco Alonso, Andrew E. H. Wheatley Jun 2012

New Routes To Copper Nanocatalysts For Fine Chemical Synthesis, Pavel Abdulkin, Yanina Moglie, Faysal Benaskar, Volker Engels, Jan Meuldijk, Volker Hessel, Emiel J. M. Hensen, Miguel Yus, Jaap C. Schouten, Francisco Alonso, Andrew E. H. Wheatley

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2012)

No abstract provided.

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Properties Of Sbsi@Cnts And Sbsi Nanowires, Marian Nowak, Krzysztof Koziol, Gregory Kozlowski, Krystian Mistewicz, Marcin Jesionek Jun 2012

Properties Of Sbsi@Cnts And Sbsi Nanowires, Marian Nowak, Krzysztof Koziol, Gregory Kozlowski, Krystian Mistewicz, Marcin Jesionek

Special Session 5: Carbon and Oxide Based Nanostructured Materials (2012)

No abstract provided.

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Extraordinary Optical Transmission And Extinction In A Terahertz Wire-Grid Polarizer, J. S. Cetnar, J. R. Middendorf, Elliott R. Brown Jun 2012

Extraordinary Optical Transmission And Extinction In A Terahertz Wire-Grid Polarizer, J. S. Cetnar, J. R. Middendorf, Elliott R. Brown

Physics Faculty Publications

A THz wire grid polarizer is simulated and demonstrated consisting of 40-μm periodic aluminum strips mounted on a polycarbonate substrate with a variable metal-to-gap ratio. Full-wave numerical simulations were performed from 100 GHz to 550 GHz predicting that the transmission in perpendicular (parallel) polarization is much higher (lower) than that predicted by geometric optics, leading to a very high extinction ratio of ∼60 dB between 100 and 550 GHz when the gaps become very small (<5 >μm). This behavior is confirmed qualitatively in experiments between 100 and 530 GHz where extinction ratios exceeding 40 dB are achieved. …

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Stable Highly Conductive Zno Via Reduction Of Zn Vacancies, David C. Look, Timothy C. Droubay, Scott A. Chambers Jan 2012

Stable Highly Conductive Zno Via Reduction Of Zn Vacancies, David C. Look, Timothy C. Droubay, Scott A. Chambers

Physics Faculty Publications

Growth of Ga-doped ZnO by pulsed laser deposition at 200 °C in an ambient of Ar and H2produces a resistivity of 1.5 × 10−4 Ω-cm, stable to 500 °C. The resistivity can be further reduced to 1.2 × 10−4 Ω-cm by annealing on Zn foil, which reduces the compensating Zn-vacancy acceptor concentration NA to 5 × 1019 cm−3, only 3% of the Ga-donor concentration ND of 1.6 × 1021 cm−3, with ND and NA determined from a degenerate mobility theory. The plasmon-resonance wavelength is only 1060 …

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A New Model For Mixing By Double-Diffusive Convection (Semi-Convection): I. The Conditions For Layer Formation, G. M. Mirouh, P. Garaud, S. Stellmach, Adrienne L. Traxler, T. S. Wood Jan 2012

A New Model For Mixing By Double-Diffusive Convection (Semi-Convection): I. The Conditions For Layer Formation, G. M. Mirouh, P. Garaud, S. Stellmach, Adrienne L. Traxler, T. S. Wood

Physics Faculty Publications

The process referred to as "semi-convection" in astrophysics and "double-diffusive convection in the diffusive regime" in Earth and planetary sciences occurs in stellar and planetary interiors in regions which are stable according to the Ledoux criterion but unstable according to the Schwarzschild criterion. In this series of papers, we analyze the results of an extensive suite of three-dimensional (3D) numerical simulations of the process, and ultimately propose a new 1D prescription for heat and compositional transport in this regime which can be used in stellar or planetary structure and evolution models. In a preliminary study of the phenomenon, Rosenblum et …

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Model For Triggering Of Non-Volcanic Tremor By Earthquakes, Naum I. Gershenzon, Gust Bambakidis Jan 2012

Model For Triggering Of Non-Volcanic Tremor By Earthquakes, Naum I. Gershenzon, Gust Bambakidis

Physics Faculty Publications

There is evidence of tremor triggering by seismic waves emanating from distant large earthquakes. The frequency content of both triggered and ambient tremor are largely identical, suggesting that this property does not depend directly on the nature of the source. We show here that the model of plate dynamics developed earlier by us is an appropriate tool for describing tremor triggering. In the framework of this model, tremor is an internal response of a fault to a failure triggered by external disturbances. The model predicts generation of radiation in a frequency range defined by the fault parameters. Thus, although the …

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Broadband 180 Degree Universal Rotation Pulses For Nmr Spectroscopy Designed By Optimal Control, Thomas E. Skinner, Naum I. Gershenzon, Manoj Nimbalkar, Wolfgang Bermel, Burkhard Luy, Steffen J. Glaser Jan 2012

Broadband 180 Degree Universal Rotation Pulses For Nmr Spectroscopy Designed By Optimal Control, Thomas E. Skinner, Naum I. Gershenzon, Manoj Nimbalkar, Wolfgang Bermel, Burkhard Luy, Steffen J. Glaser

Physics Faculty Publications

Broadband inversion pulses that rotate all magnetization components 180 degrees about a given fixed axis are necessary for refocusing and mixing in high-resolution NMR spectroscopy. The relative merits of various methodologies for generating pulses suitable for broadband refocusing are considered. The de novo design of 180 degree universal rotation pulses using optimal control can provide improved performance compared to schemes which construct refocusing pulses as composites of existing pulses. The advantages of broadband universal rotation by optimized pulses (BURBOP) are most evident for pulse design that includes tolerance to RF inhomogeneity or miscalibration. We present new modifications of the optimal …

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A Mems Photoacoustic Detector Of Terahertz Radiation For Chemical Sensing, Nathan E. Glauvitz, S. Blazevic, Ronald A. Coutu Jr., Michael N. Kistler, Ivan Medvedev, Douglas T. Petkie Jan 2012

A Mems Photoacoustic Detector Of Terahertz Radiation For Chemical Sensing, Nathan E. Glauvitz, S. Blazevic, Ronald A. Coutu Jr., Michael N. Kistler, Ivan Medvedev, Douglas T. Petkie

Physics Faculty Publications

A piezoelectric Microelectromechanical system (MEMS) cantilever pressure sensor was designed, modeled, fabricated, and tested for sensing the photoacoustic response of gases to terahertz (THz) radiation. The sensing layers were comprised of three thin films; a lead zirconate titanate (PZT) piezoelectric layer sandwiched between two metal contact layers. The sensor materials were deposited on the silicon device layer of a silicon-on-insulator (SOI) wafer, which formed the physical structure of the cantilever. To release the cantilever, a hole was etched through the backside of the wafer and the buried oxide was removed with hydrofluoric acid. Devices were then tested in a custom …

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