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Articles 1921 - 1950 of 2389

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Gis Assessment Of Environmental Impacts On Urban Forests, Richard Snow, Mary Snow Aug 2007

Gis Assessment Of Environmental Impacts On Urban Forests, Richard Snow, Mary Snow

Publications

No abstract provided.

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Testing Lorentz Symmetry With Gravity, Quentin G. Bailey Aug 2007

Testing Lorentz Symmetry With Gravity, Quentin G. Bailey

Publications

In this talk, results from the gravitational sector of the Standard-Model Extension (SME) are discussed. The weak-field phenomenology of the resulting modified gravitational field equations is explored. The application of the results to a variety of modern gravity experiments, including lunar laser ranging, Gravity Probe B, binary pulsars, and Earth-laboratory tests, shows promising sensitivity to gravitational coefficients for Lorentz violation in the SME.

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Wide-Field Survey Of Globular Clusters In M31. I. A Catalog Of New Clusters, Sang Chul Kim, Myung Gyoon Lee, Doug Geisler, Ata Sarajedini, Hong Soo Park, Ho Seong Hwang, William E. Harris, Juan C. Seguel, Ted Von Hippel Aug 2007

Wide-Field Survey Of Globular Clusters In M31. I. A Catalog Of New Clusters, Sang Chul Kim, Myung Gyoon Lee, Doug Geisler, Ata Sarajedini, Hong Soo Park, Ho Seong Hwang, William E. Harris, Juan C. Seguel, Ted Von Hippel

Publications

We present the result of a wide-field survey of globular clusters (GCs) in M31 covering a 3o x 3o field centered on M31.We have searched for GCs on CCD images taken with Washington CMT1 filters at the KPNO 0.9 m telescope using the following steps: (1) inspection of morphological parameters given by the SExtractor package such as stellarity, full width at half-maximum, and ellipticity; (2) consulting the spectral types and radial velocities obtained from spectra taken with the Hydra spectrograph at the WIYN 3.5 m telescope; and (3) visual inspection of the images of each object. We …

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Gis Analysis Of Lightning Strikes Within A Tornadic Environment, Richard Snow, Mary Snow, Nicole Kufa Jul 2007

Gis Analysis Of Lightning Strikes Within A Tornadic Environment, Richard Snow, Mary Snow, Nicole Kufa

Publications

Recent research suggests that a maximum rate of lightning strikes occurs at least 15 to 20 minutes prior to tornado formation within a supercell storm. These maxima are associated with strengthening updrafts as they appear in radar measurements. An increase in lightning rates correlates with an increase of shear in the lower part of the storm. In combination with a strong updraft or downdraft, this shear can provide the ingredients for rotation and possibly a tornado. Polarity reversal of lightning around the time of tornado touchdown also has been examined. Thus, increasing lightning flash rates and reversal of lightning strike …

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Evolution Of The American Ecological Paideia, Mary Snow, Richard K. Snow Jul 2007

Evolution Of The American Ecological Paideia, Mary Snow, Richard K. Snow

Publications

No abstract provided.

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A Multimedia Approach To Climate Change Education, Richard Snow, Mary Snow Jul 2007

A Multimedia Approach To Climate Change Education, Richard Snow, Mary Snow

Publications

This paper discusses the development of an upper-level college course on Climate Change created as part of an interdisciplinary Honors Seminar Series. The course makes use of multimedia instructional techniques to examine the physical, economic, and political dynamics of climate change. The curriculum includes an appraisal of assorted global warming websites, computer-based simulations and analysis of relevant climate data, as well as a review of the literature and other media including documentaries such as An Inconvenient Truth. The so-called global warming debate subsidized by the fossil fuel industry also is discussed.

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A Spitzer White Dwarf Infrared Survey, F. Mullally, Ted Von Hippel, Et Al. Jul 2007

A Spitzer White Dwarf Infrared Survey, F. Mullally, Ted Von Hippel, Et Al.

Publications

We present mid-infrared photometry of 124 white dwarf stars with the Spitzer Space Telescope. Objects were observed simultaneously at 4.5 and 8.0 μm with sensitivities better than 0.1 mJy. This data set can be used to test models of white dwarf atmospheres in a new wavelength regime, as well as to search for planetary companions and debris disks.

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Numerical Modeling Of A Gravity Wave Packet Ducted By The Thermal Structure Of The Atmosphere, Yonghui Yu, Michael P. Hickey Ph.D. Jun 2007

Numerical Modeling Of A Gravity Wave Packet Ducted By The Thermal Structure Of The Atmosphere, Yonghui Yu, Michael P. Hickey Ph.D.

Publications

A time-dependent and fully nonlinear numerical model is employed to solve the Navier-Stokes equations in two spatial dimensions and to describe the propagation of a Gaussian gravity wave packet generated in the troposphere. A Fourier spectral analysis is used to analyze the frequency power spectra of the wave packet, which propagates through and dwells within several thermal ducting regions. The frequency power spectra of the wave packet are derived at several discrete altitudes, which allow us to determine the evolution of the packet. This spectral analysis also clearly reveals the existence of a stratospheric duct, a mesospheric and lower thermospheric …

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Internet Enabled Remote Driving Of A Combat Hybrid Electric Power System For Duty Cycle Measurement, Jarrett Goodell, Marc Compere, Wilford Smith, Mark Brudnak, Mike Pozolo, Et Al. Jun 2007

Internet Enabled Remote Driving Of A Combat Hybrid Electric Power System For Duty Cycle Measurement, Jarrett Goodell, Marc Compere, Wilford Smith, Mark Brudnak, Mike Pozolo, Et Al.

Publications

This paper describes a human-in-the-loop motion-based simulator interfaced to hybrid-electric power system hardware, both of which were used to measure the duty cycle of a combat vehicle in a virtual simulation environment. The project discussed is a greatly expanded follow-on to the experiment published in [1,7]. This paper is written in the context of [1,7] and therefore highlights the enhancements. The most prominent of these enhancements is the integration (in real-time) of the Power & Energy System Integration Lab (P&E SIL) with a motion base simulator by means of a “long haul” connection over the Internet (a geographical distance of …

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Numerical Simulation Of Waves And Fronts In Inhomogeneous Solids, A. Berezovski, M. Berezovski, J. Engelbrecht, G. A. Maugin Jun 2007

Numerical Simulation Of Waves And Fronts In Inhomogeneous Solids, A. Berezovski, M. Berezovski, J. Engelbrecht, G. A. Maugin

Publications

Dynamic response of inhomogeneous materials exhibits new effects, which often do not exist in homogeneous media. It is quite natural that most of studies of wave and front propagation in inhomogeneous materials are associated with numerical simulations. To develop a numerical algorithm and to perform the numerical simulations of moving fronts we need to formulate a kinetic law of progress relating the driving force and the velocity of the discontinuity. The velocity of discontinuity is determined by means of the non-equilibrium jump relations at the front. The obtained numerical method generalizes the wave-propagation algorithm to the case of moving discontinuities …

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The New Class Of Dusty Daz White Dwarfs, Ted Von Hippel, Et Al. Jun 2007

The New Class Of Dusty Daz White Dwarfs, Ted Von Hippel, Et Al.

Publications

Our mid-infrared survey of 124 white dwarfs with the Spitzer Space Telescope and the IRAC imager has revealed an infrared excess associated with the white dwarf WD 2115-560 naturally explained by circumstellar dust. This object is the fourth white dwarf observed to have circumstellar dust. All four are DAZ white dwarfs, i.e., they have both photospheric Balmer lines and photospheric metal lines. We discuss these four objects as a class, which we abbreviate "DAZd," where the "d" stands for "dust." Using an optically thick, geometrically thin disk model analogous to Saturn's rings, we find that the inner disk edges are …

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Simulated Ducting Of High-Frequency Atmospheric Gravity Waves In The Presence Of Background Winds, Yonghui Yu, Michael P. Hickey Ph.D. Jun 2007

Simulated Ducting Of High-Frequency Atmospheric Gravity Waves In The Presence Of Background Winds, Yonghui Yu, Michael P. Hickey Ph.D.

Publications

A new nonlinear and time-dependent model is used to derive the total perturbation energy flux of two gravity wave packets propagating from the troposphere to the lower thermosphere. They are excited by a heat source and respectively propagate in an eastward and westward direction in the presence of a zonal wind. Analysis of the refractive index, the power spectra and the total perturbation energy flux allows us to correctly interpret the ducting characteristics of these two wave packets. In our study the wind acts as a directional filter to the wave propagations and causes noticeable spectral variations at higher altitudes. …

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Lp133-373 A New Chromospherically Active Eclipsing Dme Binary With A Distant, Cool White Dwarf Companion, T. R. Vaccaro, T. D. Oswalt, M. Rudkin, Adela Kawka, Stephane Vennes, Et Al. Jun 2007

Lp133-373 A New Chromospherically Active Eclipsing Dme Binary With A Distant, Cool White Dwarf Companion, T. R. Vaccaro, T. D. Oswalt, M. Rudkin, Adela Kawka, Stephane Vennes, Et Al.

Publications

We report the discovery of the partially eclipsing binary LP 133-373. Nearly identical eclipses along with observed photometric colors and spectroscopy indicate that it is a pair of chromospherically active dM4 stars in a circular 1.6 day orbit. Light and velocity curve modeling to our differential photometry and velocity data show that each star has a mass and radius of 0.340 ± 0.014 M☉ and 0.33 ± 0.02 R☉. The binary is itself part of a common proper motion pair with LP 133-374, a cool DC or possible DA white dwarf with a mass of 0.49-0.82 M☉, …

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Optical Absorption, Depolarization, And Scatter Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond At 1.064 Μm, Giorgio Turri, Ying Chen, Michael Bass Jun 2007

Optical Absorption, Depolarization, And Scatter Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond At 1.064 Μm, Giorgio Turri, Ying Chen, Michael Bass

Publications

No abstract provided.

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The First Detection Of Diffuse Interstellar [Oii] Emission And Confirmation That Variations In [Nii]/Hα Trace Variations In Temperature, R. J. Reynolds, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig Jun 2007

The First Detection Of Diffuse Interstellar [Oii] Emission And Confirmation That Variations In [Nii]/Hα Trace Variations In Temperature, R. J. Reynolds, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig

Publications

Using a newly developed Spatial Heterodyne Spectrometer (SHS), we have obtained the first radial velocity resolved emission-line profiles of diffuse [OII] λ3726 and λ3729 doublet emission from the warm (104 K) ionized component of our Galaxy's interstellar medium (WIM). These [OII] lines are a principal coolant for this widespread, photoionized gas and are a tracer of variations in the gas temperature resulting from unidentified heating processes that appear to be acting within the Galaxy's disk and halo.

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Lp 133-373: A New Chromospherically Active Eclipsing Dme Binary With A Distant, Cool White Dwarf Companion, T. R. Vaccaro, M. Rudkin, A. Kawka, S. Vennes, Terry D. Oswalt, Et Al. Jun 2007

Lp 133-373: A New Chromospherically Active Eclipsing Dme Binary With A Distant, Cool White Dwarf Companion, T. R. Vaccaro, M. Rudkin, A. Kawka, S. Vennes, Terry D. Oswalt, Et Al.

Publications

We report the discovery of the partially eclipsing binary LP 133-373. Nearly identical eclipses along with observed photometric colors and spectroscopy indicate that it is a pair of chromospherically active dM4 stars in a circular 1.6 day orbit. Light and velocity curve modeling to our differential photometry and velocity data show that each star has a mass and radius of 0:340 ± 0:014 MꙨ and 0:33 ± 0:02 RꙨ. The binary is itself part of a common proper motion pair with LP 133-374, a cool DC or possible DA white dwarf with a mass of 0.49Y0.82 M …

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Discovery Of Photospheric Calcium Line-Strength Variations In The Dazd White Dwarf G29-38, Ted Von Hippel, Susan E. Thompson May 2007

Discovery Of Photospheric Calcium Line-Strength Variations In The Dazd White Dwarf G29-38, Ted Von Hippel, Susan E. Thompson

Publications

Metals in the photospheres of white dwarfs with Teff between 12,000 and 25,000 K should gravitationally settle out of these atmospheres in 1 ̶ 2 weeks. Temporal variations in the line strengths of these metals could provide a direct measurement of episodic metal accretion. Using archival VLT and Keck spectroscopy, we find evidence that the DAZd white dwarf G29-38 shows significant changes in its Ca П K line strength. At the two best-observed epochs, we find that the Ca line equivalent width (EW) = 165 ̶ 4 mǺ (in 1996.885) and 280 ± 8 mǺ (in 1999.653), which is …

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Optical Properties Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond, Giorgio Turri, Ying Chen, Michael Bass, David Orchard, James E. Butler May 2007

Optical Properties Of Epitaxial Single-Crystal Chemical-Vapor-Deposited Diamond, Giorgio Turri, Ying Chen, Michael Bass, David Orchard, James E. Butler

Publications

Epitaxial single-crystal chemical-vapor-deposited diamond was obtained from Element Six Ltd. (Ascot, UK) and from Apollo Diamond (Boston, MA). Both companies provided 5 x 5 mm squares with thicknesses ranging from 0.5 to 1.5 mm. In addition, Element Six provided 10-mm-diameter disks with a thickness of 1.0 mm. The absorptance of all specimens at 1064 nm was measured by laser calorimetry, with good agreement between independent measurements at the University of Central Florida and at QinetiQ (Malvern, UK). Depolarization at 1064 nm and ultraviolet absorption properties are also reported.

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An Algorithm For Implementing Gibbs Sampling For 2pno Irt Models (Fortran), Yanyan Sheng, Todd C. Headrick May 2007

An Algorithm For Implementing Gibbs Sampling For 2pno Irt Models (Fortran), Yanyan Sheng, Todd C. Headrick

Publications

A Fortran 77 subroutine is provided for implementing the Gibbs sampling procedure to a normal ogive IRT model for binary item response data with the choice of uniform and normal prior distributions for item parameters. The subroutine requires the user to have access to the IMSL library.

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Uaa Student Showcase Journal: Recognizing Excellence (2007), N/A N/A Apr 2007

Uaa Student Showcase Journal: Recognizing Excellence (2007), N/A N/A

Publications

No abstract provided.

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Warm Gas In The Inner Disks Around Young Intermediate-Mass Stars, Sean D. Brittain, Theodore Simon, Joan R. Najita, Terrence W. Rettig Apr 2007

Warm Gas In The Inner Disks Around Young Intermediate-Mass Stars, Sean D. Brittain, Theodore Simon, Joan R. Najita, Terrence W. Rettig

Publications

The characterization of gas in the inner disks around young stars is of particular interest because of its connection to planet formation. In order to study the gas in inner disks, we have obtained high-resolution K- and M-band spectroscopy of 14 intermediate-mass young stars. In sources that have optically thick inner disks, i.e., E(K-L)>1, our detection rate of the rovibrational CO transitions is 100%, and the gas is thermally excited. Of the five sources that do not have optically thick inner disks, we only detect the rovibrational CO transitions from HD 141569. In this case, we show that the …

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Infrared High-Resolution Spectroscopy Of Post-Agb Circumstellar Disks. I. Hr 4049: The Winnowing Flow Observed?, Kenneth H. Hinkle, Sean D. Brittain, David L. Lambert Apr 2007

Infrared High-Resolution Spectroscopy Of Post-Agb Circumstellar Disks. I. Hr 4049: The Winnowing Flow Observed?, Kenneth H. Hinkle, Sean D. Brittain, David L. Lambert

Publications

High-resolution infrared spectroscopy in the 2.3-4.6 micron region is reported for the peculiar A supergiant, single-lined spectroscopic binary HR 4049. Lines from the CO fundamental and first overtone, OH fundamental, and several H2O vibration-rotation transitions have been observed in the near-infrared spectrum. The spectrum of HR 4049 appears principally in emission through the 3 and 4.6 micron region and in absorption in the 2 micron region. The 4.6 micron spectrum shows a rich 'forest' of emission lines. All the spectral lines observed in the 2.3-4.6 micron spectrum are shown to be circumbinary in origin. The presence of OH and H2O …

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Possible Identification Of A Metal-Rich Old Moving Group: High-Resolution Spectroscopy Of Candidate Members, Abigail R. Daane, Jeremy R. King, Simon C. Schuler Apr 2007

Possible Identification Of A Metal-Rich Old Moving Group: High-Resolution Spectroscopy Of Candidate Members, Abigail R. Daane, Jeremy R. King, Simon C. Schuler

Publications

Using new high-resolution spectroscopic observations from both the McDonald Observatory 2.7 m and Kitt Peak National Observatory 4 m telescopes, we observed four candidate members of the Ursa Major moving group previously suggested to instead belong to a significantly older kinematic assemblage. The Fe abundances we measure strongly suggest that these stars are not UMa members but form a more metal-rich group of stars (+0.10 ≤ [Fe/H] ≤ +0.18) with an age near 3 Gyr. Our [Ca/H] determinations corroborate this result. The apparent similarities in metallicity and previously discovered UVW space motions lend credence to prior suggestions that these stars …

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Entitles: Booker T. Washington's Signs Of Play, Susanna Ashton Apr 2007

Entitles: Booker T. Washington's Signs Of Play, Susanna Ashton

Publications

No abstract provided.

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Warm Hcn, C2h2, And Co In The Disk Of Gv Tau, E L. Gibb, K A. Vanbrunt, Sean D. Brittain, T W. Rettig Apr 2007

Warm Hcn, C2h2, And Co In The Disk Of Gv Tau, E L. Gibb, K A. Vanbrunt, Sean D. Brittain, T W. Rettig

Publications

We present the first high-resolution, ground-based observations of HCN and C2H2 toward the T Tauri binary star system GV Tau. We detected strong absorption due to HCN nu3 and weak C2H2 [nu3 and nu2+(nu4+nu5)0+] absorption toward the primary (GV Tau S) but not the infrared companion. We also report CO column densities and rotational temperatures, and present abundances relative to CO of HCN/CO~0.6% and C2H/CO~1.2% and an upper limit for CH4/CO

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Numerical Computing And Graphics For The Power Method Transformation Using Mathematica, Todd C. Headrick, Yanyan Sheng, Flaviu-Adrian Hodis Apr 2007

Numerical Computing And Graphics For The Power Method Transformation Using Mathematica, Todd C. Headrick, Yanyan Sheng, Flaviu-Adrian Hodis

Publications

This paper provides the requisite information and description of software that perform numerical computations and graphics for the power method polynomial transformation. The software developed is written in the Mathematica 5.2 package PowerMethod.m and is associated with fifth-order polynomials that are used for simulating univariate and multivariate non-normal distributions. The package is flexible enough to allow a user the choice to model theoretical pdfs, empirical data, or a user's own selected distribution(s). The primary functions perform the following (a) compute standardized cumulants and polynomial coefficients, (b) ensure that polynomial transformations yield valid pdfs, and (c) graph power method pdfs and …

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Lanchester's Equations In Three Dimensions, Christina Spradlin, Greg Spradlin Apr 2007

Lanchester's Equations In Three Dimensions, Christina Spradlin, Greg Spradlin

Publications

This paper generalizes Lanchester’s equations of warfare to partial differential equations involving time and two spatial variables. Unlike in Lanchester’s original ordinary differential equations, the distribution of armies over the battlefield must be considered. Four different modes of attack are introduced, generalizing Lanchester’s equations for area fire and for direct fire. The effect of the distribution of forces and their movement on the outcome is considered, and numerical simulations given.

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Derivation And Application Of A Conserved Orbital Energy For The Inverted Pendulum Bipedal Walking Model, Jerry E. Pratt, Sergey V. Drakunov Apr 2007

Derivation And Application Of A Conserved Orbital Energy For The Inverted Pendulum Bipedal Walking Model, Jerry E. Pratt, Sergey V. Drakunov

Publications

We present an analysis of a point mass, point foot, planar inverted pendulum model for bipedal walking. Using this model, we derive expressions for a conserved quantity, the “Orbital Energy”, given a smooth Center of Mass trajectory. Given a closed form Center of Mass Trajectory, the equation for the Orbital Energy is a closed form expression except for an integral term, which we show to be the first moment of area under the Center of Mass path. Hence, given a Center of Mass trajectory, it is straightforward and computationally simple to compute phase portraits for the system. In fact, for …

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The Case For Teaching Network Protocols To Computer Forensics Examiners, Gary C. Kessler, Matt Fasulo Apr 2007

The Case For Teaching Network Protocols To Computer Forensics Examiners, Gary C. Kessler, Matt Fasulo

Publications

"Most computer forensics experts are well-versed in basic computer hardware technology, operating systems, common software applications, and computer forensics tools. And while many have rudimentary knowledge about the Internet and simple network-lookup tools, they are not trained in the analysis of network communication protocols and the use of packet sniffers. This paper describes digital forensics applications for network analysis and includes four case studies."

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Doppler Ducting Of Short-Period Gravity Waves By Midaltitude Tidal Wind Structure, Jonathan B. Snively, Victor P. Pasko, Michael J. Taylor, Wayne K. Hocking Mar 2007

Doppler Ducting Of Short-Period Gravity Waves By Midaltitude Tidal Wind Structure, Jonathan B. Snively, Victor P. Pasko, Michael J. Taylor, Wayne K. Hocking

Publications

Multiwavelength airglow image data depicting a short-period (∼4.9 min) atmospheric gravity wave characterized by a sharp leading front have been analyzed together with synoptic meteor radar wind data recorded simultaneously from Bear Lake Observatory, Utah (41.6°N, 111.6°W). The wind data suggest the presence of a semidiurnal tide with horizontal winds peaking at around 60 m/s along the SSE direction of motion (170° from north) of this short-period wave. It was found that the gravity wave was most probably ducted because of the Doppler shift imposed by this wind structure. A marked 180° phase shift was observed between the near-infrared OH …

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