Physical Sciences and Mathematics Commons^™

A Mathematical Model Of The Dynamics Of An Optically Pumped Four-Level Solid State Laser System, Lila Freeman Roberts

Mathematics & Statistics Theses & Dissertations

This is a study of a mathematical model of the dynamics of an optically pumped four-level solid state laser system. A general mathematical model that describes the spatial and temporal evolution of the electron populations in the laser rod as well as the development of the left and right traveling photon fluxes in the cavity is developed. The model consists of a coupled set of first order semilinear partial differential equations. While the model was developed for Titanium-doped sapphire lasers, it is applicable to three and four level lasers in general.

The analysis of the model is conducted in two …

Linked Beta-Cyclodextrins, Richard Desider Nemeth

Dissertations, Theses, and Masters Projects

No abstract provided.

Cyclic Ether Synthesis Via Lewis Acid Promoted Carbon-Carbon Bond Forming Cyclization Reactions Of Unsaturated And Saturated Symmetric Acetals, Elizabeth Gonda

Dissertations, Theses, and Masters Projects

No abstract provided.

A Mathematical Model Of Tumor Growth By Diffusion, John A. Adam

Mathematics & Statistics Faculty Publications

A diffusion model of the prevascular stage of tumor growth is presented. The basic feature of such a model is the diffusion of growth inhibitor, which is produced at a spatially non-uniform rate within the tissue. Regimes of limited and unlimited tissue growth are determined, and the consistency of this and simpler models is discussed in the light of observational results.

The Energy-Dependence Of Polarization Observables In The ²H(D,Γ)⁴He Reaction, H. R. Weller, R. M. Whitton, J. Langenbrunner, Evans Hayward, W. R. Dodge, S. Kuhn, D. R. Tilley

Physics Faculty Publications

Measurements of the tensor and vector analyzing powers, A_yy(130°) and A_y(130°), have been obtained for the ²H(d,γ )⁴He reaction for energies ranging from E_d(lab) = 0.3 MeV to E_d(lab) = _{50 MeV}. The A_yy(130°) data are sensitive to the D-state present in the ground state of ⁴He and are observed to have their maximum value near E_d = 30 MeV. The vector analyzing power data show a maximum near E_d = 3 MeV. The data are compared to the results of a microscopic …

Mid-Tertiary Volcanic Rocks Of The Timberwolf Mountain Area, South-Central Cascades, Washington, Julianna M. (Julianna Maureen) Shultz

WWU Graduate School Collection

Over 3000 m of mid-Tertiary Cascade arc volcanics are exposed in the Timberwolf Mountain area of Washington's central Cascade Range. Arc rocks of the Ohanapecosh, Stevens Ridge, and Fifes Peak Formations overlie the Jura-Cretaceous Rimrock Lake inlier and sparse late Eocene(?) sedimentary rocks. Geochemical analyses of meta-basalts from the Russell Ranch and Indian Creek complexes that comprise the inlier indicate an island-arc or immature continental volcanic-arc tectonic environment for the inlier.

The early to mid Oligocene Ohanapecosh Formation is comprised of two facies within the study area. Distal, water-lain andesitic to dacitic lapilli-tuffs of the Wildcat Creek facies unconformably overlie …

The Effects Of Urbanization On The Water Balance Of The Fishtrap Creek Basin, Northwest Washington And South Central British Columbia, Charles S. (Charles Steven) Lindsay

WWU Graduate School Collection

The Fishtrap Creek basin is located in northwest Washington State and south central British Columbia. Land use in the basin is predominantly agricultural. Moderate urbanization in the past thirty-five years has increased impervious surface area in the basin from 1.8 to 8.0 percent. Monthly water balances were derived in order to quantify the effect of changing land use on the discharge of Fishtrap Creek. Stream discharges calculated from these water balances, constructed for 1952 through 1953 and 1987 through 1988, compare well with measured monthly and annual stream discharges. The favorable comparison indicates that the water- balance variables are in …

The Depositional Environment, Petrography, And Tectonic Implications Of Informally Named Middle To Late Eocene Marine Strata, Western Olympic Peninsula, Washington, Benjamin Nickolas Adams

WWU Graduate School Collection

The informally named marine strata examined in this study comprise fault bounded slivers of middle to late Eocene (Ulatizian to Narizian) siltstone, sandstone, and conglomerate exposed on the northwestern Olympic Peninsula. The strata are divided into three lithofacies: the sandstone of Bahobohosh, the siltstone of Waatch Point and the siltstone and sandstone of Bear Creek by Snavley et al. (1986). Six facies have been identified consisting of strata deposited by high- and low-density turbidites, storm waves, slumping, tidal or littoral currents, and debris flows. Relationships among the facies indicate shallow marine deposition that shoaled from below to above storm wave-base …

Cropstatus--A Computer Program To Assess The Effects Of Seasonal Weather Changes On Nebraska's Agriculture, R. E. Neild, Donald A. Wilhite, K. G. Hubbard

Drought Mitigation Center: Faculty Publications

CROPSTATUS is a series of programs residing in Nebraska's AGNET system using daily weather data to assess seasonal changes in crops, livestock, and other agricultural conditions. Assessments are based on parameters developed from accumulations of current daily temperature and precipitation data collected from a network of synoptic, climate, and automated micrometeorological stations in Nebraska in comparison with daily normals. The daily normals were derived from monthly summaries using multiple regression models to compute daily values as a function of Julian day numbers. Crop phenology models based on growing degree days were used to monitor and forecast the progress of different …

Drought Management: The Role Of Near- Real Time Weather Data, Donald A. Wilhite, Kenneth G. Hubbard

Drought Mitigation Center: Faculty Publications

The ability to collect weather data in near-real time has improved because of technological advances, enabling weather data users to obtain more weather data over wider areas, and in a more timely fashion. The number of near-real time climate networks is increasing as new applications are found for climate data. More than fifteen states in the United States have established automated weather station networks. This paper presents an overview of recent developments in automated weather data collection in the United States and gives a detailed description of the network in Nebraska.

Near-real time weather data has many applications in agricultural …

The Nebraska Agricultural Climate Situation Committee, R. E. Neild, K. G. Hubbard, Donald A. Wilhite

Drought Mitigation Center: Faculty Publications

The Nebraska Agricultural Climate Situation Committee consisting of an interdisciplinary group of extension specialists provides up-to-date information and advice on seasonal changes in crop/ weather conditions. The committee meets each Monday during the growing season to review:

1. Maps and tabular data developed by a computer program CIS /Crop Weather Information System/ that is linked to a network of weather stations and computer terminals in county agent offices.

2. Insect, plant disease and weed surveys.

3. Weekly weather and crop reports from the State/Federal System.

4. Weather outlooks from the National Weather Service.

5. Climate probabilities.

Situation reports and advisories …

Improving Projected Potential Evapotranspiration Estimates Using National Weather Service Forecasts, Steven J. Meyer, Kenneth G. Hubbard, Donald A. Wilhite

Drought Mitigation Center: Faculty Publications

In a recent survey conducted by the University of Nebraska's Center for Agricultural Meteorology and Climatology of Agricultural Network (AGNET) users, the results of potential evapotranspiration (ET_p) projections (calculated using the Blaney-Criddle approach, which employs "normal" climatic data to project ET_p estimates up to three days into the future) were labeled "unrealistic." To improve these projections, National Weather Service (NWS) forecast variables were used as input into the Blaney-Criddle and Penman equations. ET_p projections calculated according to the Penman equation, with data measured by automated weather stations as input, were assumed to represent the "best" …

Calcareous Nannofossil Biostratigraphy From Leg 101, Northern Bahamas, David K. Watkins, Joost W. Verbeek

Department of Earth and Atmospheric Sciences: Faculty Publications

Leg 101 of the Ocean Drilling Program drilled 19 holes at 11 sites to investigate the geology of the Straits of Florida and the northern Bahamas. Drilling at Site 626 indicated that the Gulf Stream has had significant flow through the Straits of Florida for at least the last 24 million years. Winnowed, foraminiferal grainstones and packstones with sparse nannofossil assemblages and the reworking of older nannofossils suggest strong bottom-current activity throughout this interval. Drilling north of Little Bahama Bank and in Exuma Sound documents the growth of platform slopes during the late Cenozoic. Nannofossil biostratigraphy of the upper Cenozoic …

Paleontological Results From Ocean Drilling Program Leg 101, David K. Watkins, Eric Fourcade, R. Mark Leckie, Allan J. Melillo, Amanda A. Palmer, Joost W. Verbeek, Jacques Butterlin, Renée Damotte, Claude Guernet, Edwige Masure, Michael J. Moran

Department of Earth and Atmospheric Sciences: Faculty Publications

Leg 101 of the Ocean Drilling Program recovered Albian through Holocene sediments from a variety of carbonate depositional environments. Data from four microplanktonic groups (calcareous nannofossils, planktonic foraminifers, radiolarians, and dinoflagellates) and four benthic groups (larger foraminifers, smaller benthic foraminifers, ostracodes, and sponge spicules) yield a biostratigraphic and paleoecologic framework for these varied sediments. Winnowed, skeletal-planktonic foraminiferal packstones and grainstones from the central Straits of Florida (Site 626) reflect a late Oligocene to Holocene history of sporadic sedimentation greatly influenced by strong bottom-current activity. Neogene to Quaternary sediments from two carbonate-slope transects (Sites 627 to 633) indicate significant slope accretion …

Comment On "Percolation In Isotropic Elastic Media.", Anthony Day, M. Thorpe

Anthony Roy Day

No abstract provided.

Efficient Application Of The Schauder-Tychonoff Theorem To Functional Perturbations Of $X^(N)=0$, William F. Trench

William F. Trench

No abstract provided.

Spectral Dimensionality Of Random Superconducting Networks, Anthony Roy Day, W. Xia, M. F. Thorpe

Anthony Roy Day

We compute the spectral dimensionality d-tilde of random superconducting-normal networks by directly examining the low-frequency density of states at the percolation threshold. We find that d-tilde=4.1±0.2 and 5.8±0.3 in two and three dimensions, respectively, which confirms the scaling relation d-tilde=2d/(2-s/ nu ), where s is the superconducting exponent and nu the correlation-length exponent for percolation. We also consider the one-dimensional problem where scaling arguments predict, and our numerical simulations confirm, that d-tilde=0. A simple argument provides an expression for the density of states of the localized high-frequency modes in this special case. We comment on the connection between our calculations …

Stability Of Networks Under Tension And Pressure, Anthony Roy Day, H. Yan, M. F. Thorpe

Anthony Roy Day

The number of zero-frequency modes of an elastic network is an important quantity in determining the stability of the network. We present a constraint-counting method for finding this number in general central-force networks that are under an external tension. The technique involves isolating the backbone and then counting constraints in the same way as for free standing networks. A detailed example of this counting is given for a random two-dimensional network subject to an external tension. The results are shown to agree with the number of zero-frequency modes as determined by a direct matrix diagonalization.