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Utah State University

2002

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Articles 61 - 68 of 68

Full-Text Articles in Physical Sciences and Mathematics

Quantifying Potential Urban Landscape Water Conservation Through Billing Data Analysis In Layton, Utah, Roger Kjelgren, Fayek A. Farag, Christopher M. U. Neale, Joanna Endter-Wada, Judith Kurtzman Jan 2002

Quantifying Potential Urban Landscape Water Conservation Through Billing Data Analysis In Layton, Utah, Roger Kjelgren, Fayek A. Farag, Christopher M. U. Neale, Joanna Endter-Wada, Judith Kurtzman

Environment and Society Faculty Publications

No abstract provided.

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Linking Ethiopian And Kenyan Pastoralists & Strengthening Cross-Border Collaboration, D. Layne Coppock, Solomon Desta Jan 2002

Linking Ethiopian And Kenyan Pastoralists & Strengthening Cross-Border Collaboration, D. Layne Coppock, Solomon Desta

Environment and Society Faculty Publications

No abstract provided.

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Unequal Arm Space-Borne Gravitational Wave Detectors, Shane L. Larson, Ronald W. Hellings, William A. Hiscock Jan 2002

Unequal Arm Space-Borne Gravitational Wave Detectors, Shane L. Larson, Ronald W. Hellings, William A. Hiscock

All Physics Faculty Publications

Unlike ground-based interferometric gravitational wave detectors, large space-based systems will not be rigid structures. When the end stations of the laser interferometer are freely flying spacecraft, the armlengths will change due to variations in the spacecraft positions along their orbital trajectories, so the precise equality of the arms that is required in a laboratory interferometer to cancel laser phase noise is not possible. However, using a method discovered by Tinto and Armstrong, a signal can be constructed in which laser phase noise exactly cancels out, even in an unequal arm interferometer. We examine the case where the ratio of the …

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The Principle Of Symmetric Criticality In General Relativity, Mark E. Fels, Charles G. Torre Jan 2002

The Principle Of Symmetric Criticality In General Relativity, Mark E. Fels, Charles G. Torre

All Physics Faculty Publications

We consider a version of Palais' principle of symmetric criticality (PSC) that is applicable to the Lie symmetry reduction of Lagrangian field theories. Given a group action on a space of fields, PSC asserts that for any group-invariant Lagrangian, the equations obtained by restriction of Euler–Lagrange equations to group-invariant fields are equivalent to the Euler–Lagrange equations of a canonically defined, symmetry-reduced Lagrangian. We investigate the validity of PSC for local gravitational theories built from a metric and show that there are two independent conditions which must be satisfied for PSC to be valid. One of these conditions, obtained previously in …

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Relative Solar And Auroral Contribution To The Polar F Region: Implications For National Space Weather Program, Michael David, Jan Josef Sojka, Robert W. Schunk, R. Heelis Jan 2002

Relative Solar And Auroral Contribution To The Polar F Region: Implications For National Space Weather Program, Michael David, Jan Josef Sojka, Robert W. Schunk, R. Heelis

All Physics Faculty Publications

When plasma in the polar cap F region becomes highly structured, patches, irregularities, and scintillations of HF signals may be observed. The topic of this paper is not the mechanism for structuring or distributing the plasma but rather the source of the plasma. By understanding the plasma source we gain insight into the specification and forecasting of ionospheric structures and irregularities as required for space weather applications. The two major sources of polar cap F region plasma are the solar EUV radiation and the auroral precipitation. The region over which solar EUV production occurs is readily modeled. In contrast, the …

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Calculation Of Spectral Degradation Due To Contaminant Films On Infrared And Optical Sensors, L. Gamble, John R. Dennison, B. Wood, J. Herrick, J. S. Dyer Jan 2002

Calculation Of Spectral Degradation Due To Contaminant Films On Infrared And Optical Sensors, L. Gamble, John R. Dennison, B. Wood, J. Herrick, J. S. Dyer

All Physics Faculty Publications

Molecular surface contaminants can cause degradation of optical systems, especially if the contaminants exhibit strong absorption bands in the region of interest. Different strategies for estimation of spectral degradation responses due to uniform films for various types of systems are reviewed. One tool for calculating the effects of contaminant film thickness on signal degradation in the mid IR region is the simulation program CALCRT. The CALCRT database will be reviewed to correlate spectral n and k values associated with specific classes of organic functional groups. Various schemes are also investigated to estimate the spectral degradation in the UV-Vis region. Experimental …

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Quantum Dynamics Of The Polarized Gowdy T3 Model, Charles G. Torre Jan 2002

Quantum Dynamics Of The Polarized Gowdy T3 Model, Charles G. Torre

All Physics Faculty Publications

The polarized Gowdy T3 vacuum spacetimes are characterized, modulo gauge, by a “point particle” degree of freedom and a function φ that satisfies a linear field equation and a nonlinear constraint. The quantum Gowdy model has been defined by using a representation for φ on a Fock space F. Using this quantum model, it has recently been shown that the dynamical evolution determined by the linear field equation for φ is not unitarily implemented on F. In this paper, (1) we derive the classical and quantum model using the “covariant phase space” formalism, (2) we show that time evolution is …

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The Lisa Optimal Sensitivity, Thomas A. Prince, Massimo Tinto, Shane L. Larson, J. W. Armstrong Jan 2002

The Lisa Optimal Sensitivity, Thomas A. Prince, Massimo Tinto, Shane L. Larson, J. W. Armstrong

All Physics Faculty Publications

The multiple Doppler readouts available on the Laser Interferometer Space Antenna (LISA) permit simultaneous formation of several interferometric observables. All these observables are independent of laser frequency fluctuations and have different couplings to gravitational waves and to the various LISA instrumental noises. Within the functional space of interferometric combinations LISA will be able to synthesize, we have identified a triplet of interferometric combinations that show optimally combined sensitivity. As an application of the method, we computed the sensitivity improvement for sinusoidal sources in the nominal, equal-arm LISA configuration. In the part of the Fourier band where the period of the …

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