Physical Sciences and Mathematics Commons^™

Comparison Of Instream Methods For Measuring Hydraulic Conductivity In Sandy Streambeds, Matthew K. Landon, David L. Rus, F. Edwin Harvey

School of Natural Resources: Faculty Publications

Streambed hydraulic conductivity (K) values were determined at seven stream transects in the Platte River Basin in Nebraska using different instream measurement techniques. Values were compared to determine the most appropriate technique(s) for use in sandy streambeds. Values of K determined from field falling- and constant-head permeameter tests analyzed using the Darcy equation decreased as permeameter diameter increased. Seepage meters coupled with hydraulic gradient measurements failed to yield K values in 40% of the trials. Consequently, Darcy permeameter and seepage meter tests were not preferred approaches. In the upper 0.25 m of the streambed, field falling- and constant-head permeameter tests …

Techniques For The Regeneration Of Wideband Speech From Narrowband Speech, Jason A. Fuemmeler, Russell C. Hardie, William R. Gardner

Electrical and Computer Engineering Faculty Publications

This paper addresses the problem of reconstructing wideband speech signals from observed narrowband speech signals. The goal of this work is to improve the perceived quality of speech signals which have been transmitted through narrowband channels or degraded during acquisition. We describe a system, based on linear predictive coding, for estimating wideband speech from narrowband. This system employs both previously identified and novel techniques. Experimental results are provided in order to illustrate the system’s ability to improve speech quality. Both objective and subjective criteria are used to evaluate the quality of the processed speech signals.

Effects Of A Large Mesospheric Temperature Enhancement On The Hydroxyl Rotational Temperature As Observedfrom The Ground, S. M.L. Melo, R. P. Lowe, W. R. Pendleton Jr., Michael J. Taylor, B. Williams, C. Y. She

All Physics Faculty Publications

The rotational temperature obtained from the rotational population distribution in the bands of the hydroxyl airglow has been shown to be a suitable proxy for the temperature at a height of 87 km [She and Lowe, 1998]. In this paper we examine in detail simultaneous observations on November 2–3, 1997, at Fort Collins, Colorado (41°N, 105°W), with both a sodium temperature lidar and the Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) OH mesospheric temperature mapper during which significant differences between the hydroxyl and lidar temperatures occur. The large differences are associated with a major temperature enhancement in the region …

Lower Willamette River Model: Model Calibration, Chris Berger, Robert Leslie Annear, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Water Environment Services of Clackamas County is in the process of planning upgrades on several of its wastewater treatment plants (WWTPs) which discharge into the Lower Willamette River. The goals of the modeling effort were to:

• Gather data to construct a computer simulation model of the Lower Willamette River system in order to evaluate the impact of the WWTP discharges on water quality

• Ensure that the model accurately represents the system physics and chemistry (flow, temperature, dissolved oxygen and nutrient dynamics) by model calibration

• Use the model to evaluate how to meet various future discharge scenarios for …

One-Gas Models With Height-Dependent Mean Molecular Weight: Effects On Gravity Wave Propagation, R. L. Walterscheid, Michael P. Hickey Ph.D.

Publications

Many models of the thermosphere employ the one-gas approximation where the governing equations apply only to the total gas and the physical properties of the gas that depend on composition (mean molecular weight and specific heats) are height-dependent. It is further assumed that the physical properties of the gas are locally constant; thus motion-induced perturbations are nil. However, motion in a diffusively separated atmosphere perturbs local values of mean molecular weight and specific heats. These motion-induced changes are opposed by mutual diffusion of the constituent gases, which attempts to restore diffusive equilibrium. Assuming that composition is locally constant is equivalent …

The Progression Of Recycling In Bowling Green, Kentucky, Susan Marklin

Masters Theses & Specialist Projects

Recycling is an important issue when dealing with solid waste. It keeps many tons of garbage out of our landfills and prolongs landfill life. Although many people in the Bowling Green area participate in the mandatory recycling program, there are still many who do not. The number of people who participate in the program has steadily grown over the past five years; however, there are still many people who need to get involved. This research argues that much effort has been put into recycling in recent years at the global, national, and local level. However, it also argues that even …

Dark Production: A Significant Source Of Oceanic Cos, M. Von Hobe, Gregory A. Cutter, A. J. Kettle, M. O. Andreae

OES Faculty Publications

Carbonyl sulfide (COS) in air and dissolved in seawater was determined during a cruise in August 1999 in the Sargasso Sea in the northwest Atlantic Ocean. Dissolved concentrations at the sea surface displayed only a weak diel cycle with a mean of 8.6 ± 2.8 pmol dm⁻³ owing to low abundance of photochemical precursors and high temperatures causing rapid hydrolysis. Depth profiles measured over the oceanic mixed layer revealed significant vertical gradients of COS concentration with higher values at the surface, suggesting that the rate of photochemical production at the surface exceeds the rate of vertical mixing. The mean …

A Confidence Measure For Boundary Detection And Object Selection, William A. Barrett, Eric N. Mortensen

Faculty Publications

We introduce a confidence measure that estimates the assurance that a graph arc (or edge) corresponds to an object boundary in an image. A weighted, planar graph is imposed onto the watershed lines of a gradient magnitude image and the confidence measure is a function of the cost of fixed-length paths emanating from and extending to each end of a graph arc. The confidence measure is applied to automate the detection of object boundaries and thereby reduces (often greatly) the time and effort required for object boundary definition within a user-guided image segmentation environment.

Houghing The Hough: Peak Collection For Detection Of Corners, Junctions And Line Intersections, William A. Barrett, Kevin D. Petersen

Faculty Publications

We exploit the Accumulator Array of the Hough Transform by finding collections of (2 or more) peaks through which a given sinusoid will pass. Such sinusoids identify points in the original image where lines intersect. Peak collection (or line aggregation) is performed by making a second pass through the edge map, but instead of laying points down in the accumulator array (as with the original Hough Transform), we compute the line integral over each sinusoid that corresponds to the current edge point. If a sinusoid passes through greater than or equal to 2 peaks, we deposit that sum/integral into a …

Image Magnification Using Level-Set Reconstruction, Bryan S. Morse, Duane Schwartzwald

Faculty Publications

Image magnification is a common problem in imaging applications, requiring interpolation to “read between the pixels”. Although many magnification/interpolation algorithms have been proposed in the literature, all methods must suffer to some degree the effects of impefect reconstruction―false high-frequency content introduced by the underlying original sampling. Most often, these effects manifest themselves as jagged contours in the image. This paper presents a method for constrained smoothing of such artifacts that attempts to produce smooth reconstructions of the image’s level curves while still maintaining image fidelity. This is similar to other iterative reconstruction algorithms and to Bayesian restoration techniques, but instead …

Fast Focal Length Solution In Partial Panoramic Image Stitching, William A. Barrett, Kirk L. Duffin

Faculty Publications

Accurate estimation of effective camera focal length is crucial to the success of panoramic image stitching. Fast techniques for estimating the focal length exist, but are dependent upon a close initial approximation or the existence of a full circle panoramic image sequence. Numerical solutions of the focal length demonstrate strong coupling between the focal length and the angles used to position each component image about the common spherical center. This paper demonstrates that parameterizing panoramic image positions using spherical arc length instead of angles effectively decouples the focal length Ji.om the image position. This new parameterization does not require an …

Improvement To The International Bathymetric Chart Of The Arctic Ocean (Ibcao): Updating The Data Base And The Grid Model, Martin Jakobsson, Norman Cherkis

Center for Coastal and Ocean Mapping

The project to develop the IBCAO grid model was initiated in 1997 with the objective of providing to the Arctic research community an improved portrayal of the seabed north of 64-deg N, in a form suitable for digital manipulation and visualization. The model was constructed from a compilation of all single-beam and multibeam echo soundings that were available for the polar region, complemented where appropriate by newly released contour information. The grid features a cell size of 2.5 x 2.5 km on a polar stereographic projection; it is constructed on the WGS 84 datum, with true scale at 75-deg N. …

Seafloor Characterization From Spatial Variation Of Multibeam Backscatter Vs. Grazing Angle, Tianhang Hou, Lloyd C. Huff, Yuri Rzhanov, Larry A. Mayer

Center for Coastal and Ocean Mapping

Backscatter vs. grazing angle, which can be extracted from multibeam backscatter data, depend on characteristics of the multibeam system and the angular responses of backscatter that are characteristic of different seafloor properties, such as sediment hardness and roughness. Changes in backscatter vs. grazing angle that are contributed by the multibeam system normally remain fixed over both space and time. Therefore, they can readily be determined and removed from backscatter data. The variation of backscatter vs. grazing angle due to the properties of sediments will vary from location to location, as sediment type changes. The sediment component of variability can be …

Volumes And Areas Of Early Weichselian Ice Dammed Lakes In Northern Russia, Martin Jakobsson, Jan Mangerud, Valery Astakov, John Inge Svendsen

Center for Coastal and Ocean Mapping

No abstract provided.

Design And Evaluation Of Processes For Fuel Fabrication: Quarterly Progress Report #1, Georg F. Mauer

Fuels Campaign (TRP)

The first three months of the project covered the following:

• Literature review: A comprehensive study of the pertinent publications pertaining to transmuter fuels composition and manufacturing processes was conducted.

• Visit at ANL West in Idaho Falls, ID: Dr. Mauer visited the ANL West facility and met with his National Laboratory Collaborator, Dr. Mitchell K. Meyer, Group Leader, Fabrication Development on October 14 and 15, 2001.

• Student Paper Presentation at the ANS Annual Meeting by Ph.D. student Mr. Jae-Kyu Lee. Title: Transmuter Fuel Fabrication Processes.

Using Boosting To Simplify Classification Models, V. Wheway

Faculty of Informatics - Papers (Archive)

Ensemble classification techniques such as bagging, boosting and arcing algorithms have been shown to lead to reduced classification errors on unseen cases and seem immune to the problem of overfitting. Several explanations for the reduction in generalisation error have been presented, with recent authors defining and applying diagnostics such as "edge" and "margin". These measures provide insight into the behaviour of ensemble classifiers, but can they be exploited further? In this paper, a four-stage classification procedure in introduced, which is based on an extension of edge and margin analysis. This new procedure allows inverse sub-contexts and difficult border regions to …

Control Of Servo Systems In The Presence Of Motor-Load Inertia Mismatch, Jeffrey W. Moscrop, C. Cook, P. Moll

Faculty of Informatics - Papers (Archive)

There are a number of performance limiting factors that concern the designers of machine tool servo systems. One such factor is the mismatch that often exists between motor and load inertias. This paper briefly discusses the results of a previous study on the factors that interact to introduce stability problems in the presence of a high motor-load inertia mismatch. The effects of such an inertia mismatch, on servo system performance, are then discussed and analysed using closed loop frequency responses. Various methods of improving the system response using fast feedback control are presented, including traditional PI control and modern methods …

Non-Target Impacts Of Strychnine Baiting To Reduce Pocket Gopher Populations On Forest Lands In The United States, Dale L. Nolte, Kimberly Wagner

USDA Wildlife Services: Staff Publications

Reforestation efforts are often severely hindered on sites that contain high populations of pocket gophers (Thmmysspp). Strychnine baiting is a technique used to suppress pocket gopher populations until seedlings are established. Strychnine bait is applied below ground in pocket gopher burrows, however, primary and secondary hazards remain a concern. A study to assess primary hazards indicated that some individual rodents died post strychnine baiting but there was not a long-term negative impact on non-target rodent populations. Possible secondary hazards reflect the potential for predators OT scavengers to encounter poisoned pocket gophers. Concerns that pocket gophers may surface before …

High-Precision Dating Of Volcanic Events (A.D. 1301–1995) Using Ice Cores From Law Dome, Antarctica, Anne S. Palmer, Tas D. Van Ommen, Mark A. J. Curran, Vin Morgan, Joe M. Souney, Paul Andrew Mayewski

Earth Science Faculty Scholarship

A record of volcanic activity over the period A.D. 1301–1995 has been extracted from three Law Dome ice cores (East Antarctica). The record dating is unambiguous at the annual level from A.D. 1807 to 1995 and has an uncertainty of ±1 year at A.D. 1301. Signals from 20 eruptions are preserved in the record, including those of two unknown eruptions with acid deposition beginning in A.D. 1810.8 and A.D. 1685.8. The beginning of the ice core signal from the A.D. 1815 Tambora eruption is observed in the austral summer of A.D. 1816/1817. The mean observed stratospheric transport and deposition time …

Tachyonic Instability And Dynamics Of Spontaneous Symmetry Breaking, Gary Felder, Lev Kofman, Andrei Linde

Physics: Faculty Publications

Spontaneous symmetry breaking usually occurs due to the tachyonic (spinodal) instability of a scalar field near the top of its effective potential at φ=0. Naively, one might expect the field φ to fall from the top of the effective potential and then experience a long stage of oscillations with amplitude O(v) near the minimum of the effective potential at φ=v until it gives its energy to particles produced during these oscillations. However, it was recently found that the tachyonic instability rapidly converts most of the potential energy V(0) into the energy of colliding classical waves of the scalar field. This …

Reflection Of A Long-Period Gravity Wave Observed In The Nightglow Over Arecibo On May 8–9, 1989?, Michael P. Hickey Ph.D.

Publications

During the Arecibo Initiative for Dynamics of the Atmosphere (AIDA) campaign in 1989 a characteristic of gravity wave perturbations observed in mesopause region airglow emissions was that airglow brightness fluctuations and airglow-derived temperature fluctuations often occurred either in phase or in antiphase. This stimulated the development of a theory suggesting that such in-phase fluctuations were most probably the result of strong reflections occurring in the mesosphere and lower thermosphere region. Recent examination of a particular wave event and application of simple WKB-type theory has appeared to support this hypothesis. Here we use a full-wave model and a WKB-type model, each …

Terahertz Gain In A Sige/Si Quantum Staircase Utilizing The Heavy-Hole Inverted Effective Mass, Richard A. Soref, Greg Sun

Physics Faculty Publications

Modeling and design studies show that a strain-balanced Si_1−xGe_x/Si superlattice onSi_1−yGe_y-buffered Si can be engineered to give an inverted effective mass HH2 subband adjacent to HH1, thereby enabling a 77 K edge-emitting electrically pumped p–i–pquantum staircase laser for THz emission at energies below the 37 meV Ge–Ge optical phonon energy. Analysis of hole-phonon scattering, lifetimes, matrix elements, and hole populations indicates that a gain of 450 cm⁻¹ will be feasible at f = 7.3 THz during 1.7 kA/cm² current injection.

Environment-Induced Degradation And Crack-Growth Studies Of Candidate Target Materials: Aaa Task-4 Quarterly (September 1 – November 30, 2001) Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The primary objective of this task is to evaluate the effect of hydrogen on environment-assisted cracking of candidate materials for applications in spallation-neutron-target (SNT) systems such as accelerator production of tritium (APT) and accelerator transmutation of waste (ATW). The materials selected for evaluation and characterization are martensitic stainless steels including HT- 9, EP 823 and 422. The susceptibility to stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of these alloys will be evaluated in environments of interest using tensile specimens under constant load and slow-strain-rate (SSR) conditions. The extent and morphology of cracking of these alloys will further be evaluated …

Development Of A Mechanistic Understanding Of High-Temperature Deformation Of Alloy Ep-823: Task 10, First Quarter Report, Ajit K. Roy, Brendan O'Toole

Transmutation Sciences Materials (TRP)

The objective of this task is to evaluate the elevated temperature tensile properties of Alloy EP-823, a leading target material for accelerator-driven waste transmutation applications. The test material will be thermally treated prior to evaluation of its tensile properties at temperatures relevant to the transmutation applications. The deformation characteristics of tensile specimens, upon completion of testing, will be evaluated by surface analytical techniques including scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The overall results are expected to provide a mechanistic understanding of high-temperature deformation behavior of Alloy EP-823 as a function of heat treatment.

Highlights of Accomplishment

• …

Fine-Tuning Solution For Hybrid Inflation In Dissipative Chaotic Dynamics, Rudnei O. Ramos

Dartmouth Scholarship

We study the presence of chaotic behavior in phase space in the preinflationary stage of hybrid inflation models. This is closely related to the problem of initial conditions associated with these inflationary types of model. We then show how an expected dissipative dynamics of fields just before the onset of inflation can solve or ease considerably the problem of initial conditions, driving the system naturally toward inflation. The chaotic behavior of the corresponding dynamical system is studied by computation of the fractal dimension of the boundary in phase space separating inflationary from noninflationary trajectories. The fractal dimension for this boundary …

Land Use Of Riparian Zones In Two Communities In The Palcazu Basin, Central Andean Amazon, Peru, Rosa E. Cossio-Solano

FIU Electronic Theses and Dissertations

The purpose of this study was to compare outcomes in forms of riparian zone land use between a native and a colonist community of the Palcazu basin in Peru. Data were gathered through a survey of 79 settler households and an ethnographic study. The results showed that riparian zones are highly valued for the conservation of fertile lowland soils by both communities. Statistical tests showed that riparian land use practices (including non-riparian land use) in both communities are similar; only significant differences were found in the percentage of protection fringe forested, in the area of riparian zone under use and …

An Optimal Importance Sampling Method For A Transient Markov System, H. Qi, Y. C. Wei, L. Wei

Faculty of Informatics - Papers (Archive)

In this paper an optimal importance sampling (IS) method is derived for a transient markov system. Several propositions are presented. It is showned that the optimal IS method is unique, and it must converge to the standard Monte Carlo (MC) simulation method when the sample path length approaches infinity. Therefore, it is not the size of the state space of the Markov system, but the sample path length, that limits the efficiency of the IS method. Numerical results are presented to support the argument.

Magnetite Morphology And Life On Mars, Peter R. Buseck, Rafal E. Dunin-Borkowski, Bertrand Devouard, Richard B. Frankel, Martha R. Mccartney, Paul A. Midgley, Mihály Pósfai, Mathew Weyland

Physics

Nanocrystals of magnetite (Fe₃O₄) in a meteorite from Mars provide the strongest, albeit controversial, evidence for the former presence of extraterrestrial life. The morphological and size resemblance of the crystals from meteorite ALH84001 to crystals formed by certain terrestrial bacteria has been used in support of the biological origin of the extraterrestrial minerals. By using tomographic and holographic methods in a transmission electron microscope, we show that the three-dimensional shapes of such nanocrystals can be defined, that the detailed morphologies of individual crystals from three bacterial strains differ, and that none uniquely match those reported from …

Interactions Of Ultrashort, Ultrahigh Intensity Laser Pulses With Underdense Plasmas, Xiaofang Wang, Wei Yu, Sterling Backus, Margaret Murnane, Henry Kapteyn, Donald P. Umstadter

Donald Umstadter Publications

The interactions of ultraintense laser pulses with underdense plasmas are studied in a new regime in which the longitudinal spatial extent of the pulse duration is close to both the laser focal spot size and the plasma wavelength.

Laser Acceleration Of Protons From Thin Film Targets, K. Flippo, Sudeep Banerjee, V. Yu. Bychenkov, S. Gu, Anatoly Maksimchuk, G. Mourou, K. Nemoto, Donald P. Umstadter

Donald Umstadter Publications

A collimated beam of fast protons, with energies as high as 10 MeV and total number of 10⁹, confined in a cone angle of 40°±10° has been observed when a 10 TW laser with frequencies either ω₀ (corresponding to 1 μm) or 2ω₀ was focused to an intensity of a few times 10¹⁸ W/cm² on the surface of a thin film target. The protons, which originate from impurities on the front side of the target, are accelerated over a region extending into the target and exit out the backside in a direction normal to …