Physical Sciences and Mathematics Commons^™

Atmospheric Circulation Anomalies Associated With 1996/1997 Summer Precipitatipn Events On Sajama Ice Cap, Bolivia, Mathias Vuille, Douglas R. Hardy, Carsten Braun, Frank Keimig, Raymond S. Bradley

Raymond S Bradley

The analysis of atmospheric circulation anomalies related to snowfall eVents on Sajama volcano (Bolivian Andes) provides important information for the calibration of an ice core, recently recovered from the summjt. Seventeen precipitation episodes were recorded on Sajama volcano during the 1996/1997 summer season (November 1996 to Marcb 1997) by snow depth sensors and additional measurements of an automatic weather station located on the summit. The analysis of atmospheric circulation patterns during these events is pased on zonal and meridional wind, air temperature, relative humiqity, geopotential height and horizontal divergence at three pressure levels (400, 500, and 700 hPa levels), atmosphenc …

Two Capture Techniques For American White Pelicans And Great Blue Herons, D. Tommy King, John D. Paulson, Dwight J. Leblanc, Kevin Bruce

United States Department of Agriculture Wildlife Services: Staff Publications

We describe two techniques for capturing American White Pelicans (Pelecanus erythrorhynchos), Great Blue Herons (Ardea herodias), and other large wading birds in aquatic habitats. One technique involved using #3 padded jaw leghold traps modified by replacing both factory coil springs with weaker #1.5 coil springs, to reduce the closing force of the jaws, and replacing the factory chain with a length of aircraft cable and an elastic shock cord, to minimize injury caused by lunging. The second technique involved using a modified portable rocket net that can be set in shallow water. We captured 142 American …

New Algorithms For Moving-Bank Multiple Model Adaptive Estimation, Juan R. Vasquez

Theses and Dissertations

The focus of this research is to provide methods for generating precise parameter estimates in the face of potentially significant parameter variations such as system component failures. The standard Multiple Model Adaptive Estimation (MMAE) algorithm uses a bank of Kalman filters, each based on a different model of the system. A new moving-bank MMAE algorithm is developed based on exploitation of the density data available from the MMAE. The methods used to exploit this information include various measures of the density data and a decision-making logic used to move, expand, and contract the MMAE bank of filters. Parameter discretization within …

Pressure Ionization And Line Merging In Strongly Coupled Plasmas Produced By 100-Fs Laser Pulses, M. Nantel, G. Ma, S. Gu, C.Y. Côté, J. Itatani, Donald Umstadter

Donald Umstadter Publications

Time- and space-resolved extreme ultraviolet spectra of carbon plasmas, created with 100-fs laser pulses, are obtained with the novel technique of picosecond jitter-free streak-camera averaging. Spectroscopic diagnostics indicate electron densities and temperatures evolving from 10²³ to 10²¹ cm^-3 and 80 to 50 eV, respectively, implying less than one particle in a Debye sphere at early times. The emission reveals conditions of extreme pressure ionization and line merging. Comparisons of the experimental spectra with numerical simulations validate the use of the Inglis-Teller limit for line merging, and confirm that pressure ionization models based on the Debye-Huckel potential are …

Search For Inclusive B→Sl+L-, S. Glenn, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We have searched for the effective flavor changing neutral-current decays b→sl⁺l^- using an inclusive method. We set upper limits on the branching ratios B(b→ se⁺e^-) < 5.7 X 10^-5, B(b→ sμ⁺μ^-) < 5.8 X 10^-5 and Bb→se⁺μ^-) < 2.2 3 10^-5 [at 90% confidence level (C.L.)]. Combing the dielectron and dimuon decay modes we find b→sl⁺l^-) < 4.2 X 10^-5 (at 90% C.L.).

Orthogonal Polynomial Projectors For The Projector Augmented Wave Method Of Electronic Structure Calculations, N. A. W. Holzwarth, G. E. Matthews, A. R. Tackett, Rodney Dunning

Chemistry & Physics Faculty Publications

The projector augmented wave (PAW) method for electronic structure calculations developed by Blochl [Phys. Rev. B 50, 17 953 (1994)] has been very successfully used for density functional studies. It has the numerical advantages of pseudopotential techniques while retaining the physics of all-electron formalisms. We describe a method for generating the set of atom-centered projector and basis functions that are needed for the PAW method. This scheme chooses the shapes of the projector functions from a set of orthogonal polynomials multiplied by a localizing weight factor. Numerical benefits of the scheme result from having direct control of the …

Particulate Sizing And Emission Indices For A Jet Engine Exhaust Sampled At Cruise, Donald E. Hagen, Philip D. Whitefield, J. Paladino, Max B. Trueblood, H. Lilenfeld

Physics Faculty Research & Creative Works

Particle size and emission indices measurements for jet engines, primarily the Rolls Royce RB211 engines on a NASA 757 aircraft are reported. These data were used to estimate the fraction of fuel sulfur that was converted to particulates. These measurements were made in-situ with the sampling aircraft several kilometers behind the source. Some complimentary ground measurements on the same source aircraft and engines are also reported. Significant differences are seen between the ground observations and the in-situ observations, indicating that plume processes are changing the aerosol' s characteristics.

Polydispersivity Of Non-Critical Field-Induced Fluctuations In Febr2, Christian Binek

Christian Binek Publications

The field and temperature dependence of the complex low-frequency susceptibility of the metamagnet FeBr2 exhibits large anomalies in the vicinity of the second-order phase boundary Hc(T). The low-frequency losses reflect polydispersive dynamics with a broad distribution of relaxation times peaking at τ ≈ 0.2 s. The dispersion, χ versus ƒ, is well described within Chamberlin's model of dynamically coupled domains. The heterogeneous glass-like response gives rise to the intuitive picture of a magnetic fluid of high viscosity.

The Two-Dimensional Ising Model: Mean-Field And Monte Carlo Results For Equilibrium And Nonequilibrium Transitions, Kevin Scott Brown

Honors Theses

No abstract provided.

Shape Invariance And Its Connection To Potential Algebra, Asim Gangopadhyaya, Jeffrey Mallow, Uday P. Sukhatme

Physics: Faculty Publications and Other Works

Exactly solvable potentials of nonrelativistic quantum mechanics are known to be shape invariant. For these potentials, eigenvalues and eigenvectors can be derived using well known methods of supersymmetric quantum mechanics. The majority of these potentials have also been shown to possess a potential algebra, and hence are also solvable by group theoretical techniques. In this paper, for a subset of solvable problems, we establish a connection between the two methods and show that they are indeed equivalent.

Preparation Of Gold-Coated Molybdenum Articles And Articles Prepared Thereby, Timothy S. Romano, Tom K. Evans, Gary B. Hughes, Karl H. Neumann

Statistics

A gold-coated molybdenum article (30) is made by furnishing a substrate (32) made of pure molybdenum or an alloy of molybdenum, and preparing a slurry of gold powder, acrylic binder, and acetone liquid carrier. The slurry is applied to a portion of a surface of the substrate. The substrate with applied slurry is heated in vacuum or inert atmosphere to an elevated temperature, preferably about 2040.degree. F., and thereafter cooled to ambient temperature. The result is an article (30) having at least a portion of the substrate (32) covered with an adherent gold coating (34).

Exact Real Computational Arithmetic Via Infinite Composition Of Mobiüs Transformations As Presented By Dr. Peter John Potts, Et Al., David Michael Robertson

Honors Theses

No abstract provided.

Resistivity Of Boron-Doped Diamond Microcrystals, M. D. Jaeger, S. Hyun, Anthony Roy Day, M. F. Thorpe, B. Golding

Anthony Roy Day

We describe measurements of the electrical resistivity of micron-size crystallites of boron-doped diamond. Electron-beam lithography was employed for writing sample-specific contacts on small, well-faceted diamond crystals grown by chemical-vapor deposition on silicon substrates. After generating a three-dimensional computer model of the crystallite, a finite-element analysis was used to calculate the internal electrostatic potential distribution. Multiterminal resistance measurements, in conjunction with a computed geometrical factor, enabled the absolute resistivity to be determined. We find that the resistivities obtained from two different crystallites agree to better than 10%. The results are compared with transport measurements on a large-area homoepitaxial diamond film grown …

A Teachers Guide: The Basic Characteristics Of Wetlands And Why They Are Important To The Environment, Charles W. Fisher

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this thesis is to develop an educational guide about wetlands that can be used by 3rd- 12th grade teachers. This guide will enable students to learn about wetlands and why they are important to our environment. I will provide examples and a series of activities that teachers can use in the classroom to help their students better understand the benefits and function of wetlands.

Form, Function, And Evolution In Skulls And Teeth Of Bats, Patricia W. Freeman

School of Natural Resources: Faculty Publications

Bats provide a model system for tracking change from the primitive mammalian tooth pattern to patterns indicating the more-derived food habits of carnivory, nectarivory, frugivory, and sanguinivory. Whereas microchiropteran bats show all these transitions, megachiropterans illustrate an alternative pattern concerned only with frugivory and nectarivory. In microchiropterans, it is likely that carnivory nectarivory, frugivory, and sanguinivory are all derived from a dilambdodont insectivorous tooth pattern. Megachiropterans are troublesome because they appear as nectarivores or frugivores without a clear relationship to ancestral taxa.

The nature of the food item and how teeth respond to that item evolutionarily is an issue I …

Constructing High Order Perceptrons With Genetic Algorithms, Timothy L. Andersen, Tony R. Martinez

Faculty Publications

Constructive induction, which is defined to be the process of constructing new and useful features from existing ones, has been extensively studied in the literature. Since the number of possible high order features for any given learning problem is exponential in the number of input attributes (where the order of a feature is defined to be the number of attributes of which it is composed), the main problem faced by constructive induction is in selecting which features to use out of this exponentially large set of potential features. For any feature set chosen the desirable characteristics are minimality and generalization …

Quantum Associative Memory With Exponential Capacity, Tony R. Martinez, Dan A. Ventura

Faculty Publications

Quantum computation uses microscopic quantum level effects to perrform computational tasks and has produced results that in some cases are exponentially faster than their classical counterparts by taking advantage of quantum parallelism. The unique characteristics of quantum theory may also be used to create a quantum associative memory with a capacity exponential in the number of neurons. This paper covers necessary high-level quantum mechanical ideas and introduces a simple quantum associative memory. Further, it provides discussion, empirical results and directions for future work.

Optimal Control Using A Neural/Evolutionary Hybrid System, Tony R. Martinez, Dan A. Ventura

Faculty Publications

One of the biggest hurdles to developing neurocontrollers is the difficulty in establishing good training data for the neural network. We propose a hybrid approach to the development of neurocontrollers that employs both evolutionary computation (EC) and neural networks (NN). EC is used to discover appropriate control actions for specific plant states. The survivors of the evolutionary process are used to construct a training set for the NN. The NN leams the training set, is able to generalize to new plant states, and is then used for neurocontrol. Thus the EC/NN approach combines the broad, parallel search of EC with …

Reaction Sequence Of Iron Sulfide Minerals In Bacteria And Their Use As Biomarkers, Mihály Pósfai, Peter R. Buseck, D. A. Bazylinski, Richard B. Frankel

Physics

Some bacteria form intracellular nanometer-scale crystals of greigite (Fe₃S₄) that cause the bacteria to be oriented in magnetic fields. Transmission electron microscope observations showed that ferrimagnetic greigite in these bacteria forms from nonmagnetic mackinawite (tetragonal FeS) and possibly from cubic FeS. These precursors apparently transform into greigite by rearrangement of iron atoms over a period of days to weeks. Neither pyrrhotite nor pyrite was found. These results have implications for the interpretation of the presence of pyrrhotite and greigite in the martian meteorite ALH84001.

1998 - The Third Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the Third Annual Symposium of Student Scholars, held on May 8th, 1998. Includes abstracts from the presentation and posters.

A Comparison Between The Cisd[Tq] Wave Function And Other Highly Correlated Methods: Molecular Geometry And Harmonic Vibrational Frequencies Of Mgh2, Gregory S. Tschumper, Henry F. Schaefer

Chemistry Faculty Research & Creative Works

The linear MgH2 molecule was selected as a model system to compare the total electronic energy (ETOT). equilibrium bond length (re), and vibrational frequency (ωn) predictions from six different configuration interaction (CI) and coupled cluster (CC) methods using three large correlation consistent basis sets. The three CI procedures employed incorporated all single and double substitutions (CISD) as well as all triple and quadruple substitutions (CISDTQ) or limited triple and quadruple substitutions (CISD[TQ]). The remaining three CC schemes included all single and double excitations (CCSD) as well as all triple excitations (CCSDT) or a perturbative approximation of the triple excitations [CCSD(T)]. …

Breeding Bird Utilization Of Shelterwood-Cut Oak Stands In Buckingham County, Virginia, Kim Marie Mcdonald

Theses & Honors Papers

Breeding bird populations on three shelterwood cut oak stands in Buckingham County, Virginia were studied using Breeding Bird Census (BBC) techniques. The stands were cut partly or entirely during the year prior to the 1997 breeding season, when the BBCs were conducted. The plots were established as part of a study of oak regeneration following controlled bums in the Virginia piedmont. Canopy cover on the plots averaged 66.8% after the cuts and total basal area averaged 41915 cm2/acre. At least 23 species of birds had territories partly or entirely on at least one of the plots, and at least nine …

Metamorphic Epiphany -- 3d Animation, Michael G. Corr

Senior Scholar Papers

As far back as I can remember, I have always been interested in studio art. Whether it be painting, drawing, printmaking, or photography, it has consistently been a part of my life. Upon enrolling in Colby, I became interested in computers and decided to major my undergraduate college career in Computer Science. Not forgetting past interests, I continued my studio art education, taking several classes within the Art department. In due time, I began combining interests and began studying Computer Graphics and Design. With limited resources in this field at Colby, the majority of my computer graphic education and experience …

Molecular Design And Association Constants Of Nizatidine-Guest Complexes, Elizabeth Corbeil

Honors Theses

Nizatidine, N-[2-[[[2-[(dimethylamino)metbyl]-4-thiazolyl]methyl]thio]ethyl]-N'methyl- 2-nitro-l,l-ethenediamine (Axid"), has been investigated for its potential to act as a host in guest-host complexes. Nizatidine binds with the guests through hydrogen bonding and pi-pi interactions. Guest-host studies were conducted using fluorescence quenching, calorimetry, NMR and invisible experiments. The lowest energy conformation of nizatidine is found to be U-shaped through theoretical calculations. Fluorescence experiments indicated that tryptophan and pyridoxine had large association constants. Further studies using calorimetry and NMR techniques concluded that no complexation had occurred. Complexation experiments have been done to find guests that complex with nizatidine. Caffeine, luminol, nicotinamide, phenylalanine, pyridoxine, pyrogallol, and tryptophan were …

Stability And Reconstruction For An Inverse Problem For The Heat Equations, Kurt M. Bryan, Lester Caudill

Mathematical Sciences Technical Reports (MSTR)

We examine the inverse problem of determining the shape of some unknown portion of the boundary of a region W from measurements of the Cauchy data for solutions to the heat equation on W. By suitably linearizing the inverse problem we obtain uniqueness and continuous dependence results. We propose an algorithm for recovering estimates of the unknown portion of the surface and use the insight gained from a detailed analysis of the inverse problem to regularize the inversion. Several computational examples are presented.

Radial Dependence Of The Nucleon Effective Mass In 10b, L J. De Bever, R S. Hicks, R A. Miskimen, Gerald Alvin Peterson

Gerald Alvin Peterson

The dynamic properties of the atomic nucleus depend strongly on correlations between the nucleons. We present a combined analysis of inelastic electron-scattering data and electron-induced proton knockout measurements in an effort to obtain phenomenological information on nucleon-nucleon correlations. Our results indicate that the ratio of radial wave functions extracted from precise 10B(e,e′) and 10B(e,e′p) measurements evolve from an interior depression for small Em, characteristic of short-range correlations, to a surface-peaked enhancement for larger Em, characteristic of long-range correlations. This observation can be interpreted in terms of the nucleon effective mass.

Observation Of The Radiative Decay D*+→D+Γ, J. Bartelt, Kenneth A. Bloom, Cleo Collaboration

Kenneth Bloom Publications

We have observed a signal for the decay D^*+→D⁺γ at a significance of 4 standard deviations. From the measured branching ratio B(D^*+→D⁺γ)/ B(D^*+→ D⁺+pi⁰ = 0.055 ± 0.014 ± 0.010 we find B(D^*+→D⁺γ)= 0.017 ± 0.004 ± 0.003, where the first uncertainty is statistical and the second is systematic. We also report the highest precision determination of the remaining D^*+ branching fractions.

Accounting For Sample Selection Bias In Louisiana Hmo Satisfaction Studies, Travis Warziniack

Honors Theses

No abstract provided.

The Dirichlet Problem And Its Physical Motivations, Andrew E. Pitts

Honors Theses

In this work, we explore the basics of harmonic function theory and its relationship to problems in the theory of heat diffusion. In particular, we will focus on the classical Dirichlet problem.

Isolation And Structure Of Sc2@C74, Harry Dorn, Steven Stevenson, Paul Burbank, Kim Harich, Z. Sun, T. Glass, Mark Anderson, Donald Bethune, M. Sherwood

Mark R. Anderson

No abstract is currently available.