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Articles 3031 - 3060 of 3797

Full-Text Articles in Physical Sciences and Mathematics

Urbanization And Its Relationship To Water Quality Within The Bronson Creek Watershed, Jason Cristopher Creech Apr 2003

Urbanization And Its Relationship To Water Quality Within The Bronson Creek Watershed, Jason Cristopher Creech

Environmental Science and Management Professional Master's Project Reports

A watershed analysis project was undertaken to investigate the impact of urbanization on the water quality with Bronson Creek; a small urban stream in the metropolitan area of Portland, Oregon. Total Maximum Daily Loads (TMDLs) have been established for several water quality parameters within the watershed.

Water quality data were collected at nine sampling along Bronson Creek by Clean Water Services, a local public utility charged with storm water management and water quality protection duties. Only seven water quality parameters were included in the analysis; they were 1) temperature, 2) total phosphorous, 3) ortho-phosphate, 4) ammonia, 5) total nitrogen, 6) …


An Analysis Of The Oregon Coastal Exchange Requirement, Jordan Vinograd Mar 2003

An Analysis Of The Oregon Coastal Exchange Requirement, Jordan Vinograd

Center for Lakes and Reservoirs Publications and Presentations

This report was generated at the request of the Oregon Ballast Water Task Force to address the issue of coastal shipping and exchange requirements along the West Coast of North America. The Oregon Ballast Water Management Program was established by SB 895 during the 2001 legislative session to address the introduction of aquatic nuisance species when ballast water is discharged from ships. There are several levels of ballast water management as established by the National Invasive Species Act of 1996. However, the national program does not address the issues of interstate vessel voyages. Therefore, California, Washington and Oregon have establishedm …


High-Resolution Near-Field Raman Microscopy Of Single-Walled Carbon Nanotubes, Achim Hartschuh, X. Sunney Xie, Lukas Novotny, Erik J. Sánchez Mar 2003

High-Resolution Near-Field Raman Microscopy Of Single-Walled Carbon Nanotubes, Achim Hartschuh, X. Sunney Xie, Lukas Novotny, Erik J. Sánchez

Physics Faculty Publications and Presentations

We present near-field Raman spectroscopy and imaging of single isolated single-walled carbon nanotubes with a spatial resolution of approximately 25 nm. The near-field origin of the image contrast is confirmed by the measured dependence of the Raman scattering signal on tip-sample distance and the unique polarization properties. The method is used to study local variations in the Raman spectrum along a single single-walled carbon nanotube.


Hillslope Nutrient Dynamics Following Upland Riparian Vegetation Disturbance, J. Alan Yeakley, David C. Coleman, Bruce L. Haines, Brian D. Kloeppel, Judy L. Meyer, Wayne T. Swank, Barry W. Argo, James M. Deal, Sharon F. Taylor Mar 2003

Hillslope Nutrient Dynamics Following Upland Riparian Vegetation Disturbance, J. Alan Yeakley, David C. Coleman, Bruce L. Haines, Brian D. Kloeppel, Judy L. Meyer, Wayne T. Swank, Barry W. Argo, James M. Deal, Sharon F. Taylor

Environmental Science and Management Faculty Publications and Presentations

We investigated the effects of removing near-stream Rhododendron and of the natural blowdown of canopy trees on nutrient export to streams in the southern Appalachians. Transects were instrumented on adjacent hillslopes in a first-order watershed at the Coweeta Hydrologic Laboratory (35°03′N, 83°25′W). Dissolved organic carbon (DOC), K+, Na+, Ca2+, Mg2+, NO3-- -N, NH4+ -N, PO43---P, and SO42- were measured for 2 years prior to disturbance. In August 1995, riparian Rhododendron on one hillslope was cut, removing 30% of total woody biomass. In October …


Enhanced Magnetic Quantum Oscillations In The Mixed State Of A Two-Dimensional Organic Superconductor, J. Wosnitza, J. Hagel, P. J. Meeson, D. Bintley, J. A. Schlueter, Javid Mohtasham, Rolf Walter Winter, Gary L. Gard Feb 2003

Enhanced Magnetic Quantum Oscillations In The Mixed State Of A Two-Dimensional Organic Superconductor, J. Wosnitza, J. Hagel, P. J. Meeson, D. Bintley, J. A. Schlueter, Javid Mohtasham, Rolf Walter Winter, Gary L. Gard

Chemistry Faculty Publications and Presentations

We report on de Haas–van Alphen (dHvA) oscillations observed in the mixed state of the organic superconductor β″–(BEDT-TTF)₂SF₅CH₂CF₂SO₃ (BEDT-TTF stands for bisethylenedithio-tetrathiafulvalene) utilizing the field-modulation technique and torque magnetometry. At low temperatures (30 mK), the dHvA signal persists down to 1.4 T well below the upper critical field Bc2≈3.6T. Contrary to most theoretical predictions and previous experimental findings, no additional damping of the dHvA-oscillation amplitude, but a reduced damping of the dHvA signal is found. This highly unusual effect might indicate a reduced quasiparticle scattering rate or an additional oscillatory contribution in the superconducting state.


Comparative Standards For Intensive Livestock Operations In Canada, Mexico, And The United States, Jerry Speir, Marie-Ann Bowden, David E. Ervin, Jim Mcelfish, Rosario P. Espejo, Tim Whitehouse, Chantal L. Carpentier Feb 2003

Comparative Standards For Intensive Livestock Operations In Canada, Mexico, And The United States, Jerry Speir, Marie-Ann Bowden, David E. Ervin, Jim Mcelfish, Rosario P. Espejo, Tim Whitehouse, Chantal L. Carpentier

Economics Faculty Publications and Presentations

Livestock farming has been transformed in the past twenty years from a business dominated by relatively small producers to one dominated by large facilities raising thousands of animals. A side effect of this development has been a new set of environmental concerns unique to this industry. While regulation of livestock agriculture has historically been a state/provincial and local matter, governments from the local to the federal level have found themselves grappling with the issues created by these new, concentrated facilities. This Report surveys the current environmental requirements for "intensive livestock operations" (ILOs) in the United States, Mexico and Canada. The …


High-Field Magnetic Resonant Properties Of Β’–(Et)2sf5cf2so3, Gary L. Gard, Rolf Walter Winter, J. A. Schlueter, Brian H. Ward, E. Jobiliong, A. P. Reyes, P. Kuhns, J. Krzystek, J. S. Brooks, S. A. Zvyagin, B. Rutel Jan 2003

High-Field Magnetic Resonant Properties Of Β’–(Et)2sf5cf2so3, Gary L. Gard, Rolf Walter Winter, J. A. Schlueter, Brian H. Ward, E. Jobiliong, A. P. Reyes, P. Kuhns, J. Krzystek, J. S. Brooks, S. A. Zvyagin, B. Rutel

Chemistry Faculty Publications and Presentations

The charge transfer salt β′-(ET)₂SF₅CF₂SO₃, which has previously been considered a spin-Peierls material with a TSP;33 K, is examined using high-resolution high-field sub-millimeter/millimeter wave electron spin resonance (ESR), and nuclear magnetic resonance (NMR) techniques. A peak in the nuclear spin-lattice relaxation behavior in fields of 8 T, accompanied by a broadening and paramagnetic shift of the resonance line, indicates a phase transition at Tc~20 K. A pronounced change in the high-field ESR excitation spectra at ~24 T, observed at Tc~20 K, may indicate the onset of antiferromagnetic (AFM) correlations of the low temperature phase in β′-(ET)₂SF₅CF₂SO₃. Peculiarities of the low-temperature …


Sensorimotor Coordination And The Structure Of Space, Gin Mccollum Jan 2003

Sensorimotor Coordination And The Structure Of Space, Gin Mccollum

Gin McCollum

Embedded in neural and behavioral organization is a structure of sensorimotor space. Both this embedded spatial structure and the structure of physical space inform sensorimotor control. This paper reviews studies in which the gravitational vertical and horizontal are crucial. The mathematical expressions of spatial geometry in these studies indicate methods for investigating sensorimotor control in freefall.

In freefall, the spatial structure introduced by gravitation – the distinction between vertical and horizontal – does not exist. However, an astronaut arriving in space carries the physiologically-embedded distinction between horizontal and vertical learned on earth. The physiological organization based on this distinction collapses …


Estimating Watershed Biodiversity: An Empirical Study Of The Chesapeake Bay In Maryland, Usa, Junko Morimoto, Helena Voinov, Matthew A. Wilson, Robert Costanza Jan 2003

Estimating Watershed Biodiversity: An Empirical Study Of The Chesapeake Bay In Maryland, Usa, Junko Morimoto, Helena Voinov, Matthew A. Wilson, Robert Costanza

Institute for Sustainable Solutions Publications and Presentations

There has been increasing demand for rigorous methods for evaluating biodiversity, one of the ecosystem services that sustains and fulfills human life. After carefully examining the literature, we found three key points that should be taken into account when we evaluate biodiversity. The first point is that any "indicator species" tends to be a leaky target of biodiversity. The second point is that "buffering" that is useful for representing the ecological concept of boundaries should have scientific meanings. The third point is that a "watershed" that integrates most natural processes is advantageous as the spatial range for evaluation. Based on …


The Role Of Lateral And Vertical Shear In Tributary Flow Toward A West Antarctic Ice Stream, Christina L. Hulbe, Weili Wang, Ian R. Joughin, Martin J. Siegert Jan 2003

The Role Of Lateral And Vertical Shear In Tributary Flow Toward A West Antarctic Ice Stream, Christina L. Hulbe, Weili Wang, Ian R. Joughin, Martin J. Siegert

Geology Faculty Publications and Presentations

Narrow lateral shear margins are the most distinctive visual feature of the West Antarctic ice streams. Large shear stresses within these layers support the majority of the gravitational driving stress within a fast-flowing ice stream.The present contribution looks upstream, to the tributaries that feed ice-stream onsets, and considers the effects of both horizontal and vertical shear on their flow. Numerical and direct simulations of vertical and horizontal shear are used.Vertical shear, simulated using an anisotropic flow law, is of particular interest.We conclude that by isolating overlying ice from large-amplitude variations in bed elevation -vertical shear margins - play an important …


Subglacial Thermal Balance Permits Ongoing Grounding Line Retreat Along The Siple Coast Of West Antarctica, Byron R. Parizek, Richard B. Alley, Christina L. Hulbe Jan 2003

Subglacial Thermal Balance Permits Ongoing Grounding Line Retreat Along The Siple Coast Of West Antarctica, Byron R. Parizek, Richard B. Alley, Christina L. Hulbe

Geology Faculty Publications and Presentations

Changes in the discharge of West Antarctic ice streams are of potential concern with respect to global sea level. The six relatively thin, fast-flowing Ross ice streams are of interest as low-slope end-members among Antarctic ice streams. Extensive research has demonstrated that these "rivers of ice" have a history of relatively high-frequency (óO(100) years), asynchronous discharge variations with evolving lateral boundaries. Amidst this variability, a ~1300 km grounding-line retreat has occurred since the Last GlacialMaximum. Numerical studies of Ice Stream D (Parizek and others, 2002) indicate that a proposed thermal-regulation mechanism(Clarke and Marshall, 1998; Hulbe and MacAyeal,1999; Tulaczyk and others, …


Upper Spokane River Model: Model Calibration, 2001, Chris Berger, Robert Leslie Annear, Benjamin Welle Jan 2003

Upper Spokane River Model: Model Calibration, 2001, Chris Berger, Robert Leslie Annear, Benjamin Welle

Civil and Environmental Engineering Faculty Publications and Presentations

The Upper Spokane River system under consideration is located in the Northeastern part of Washington State and runs from the Stateline with Idaho, River mile (RM) 96.0, downstream to Long Lake dam at RM 32.5. Figure 1 shows the river system and an outline the boundaries of the City of Spokane.

The Washington Department of Ecology (Ecology) is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). As a result, Ecology and the Corps of Engineers funded a study to develop a water quality and hydrodynamic model of …


Tracers Of Wood Smoke, M. A. K. Khalil, R. A. Rasmussen Jan 2003

Tracers Of Wood Smoke, M. A. K. Khalil, R. A. Rasmussen

Physics Faculty Publications and Presentations

Smoke from wood burning is a significant source of air pollution in many parts of the world. When several sources simultaneously cause air pollution, it is often difficult to determine how much comes from wood burning. Woodsmoke has unique chemical characteristics that can be used as indicators, including elemental composition, particularly potassium and chlorine, the ratios of organic and elemental carbon, and gases such as methyl chloride. This paper deals with formulating and applying the chemical mass balance approach incorporating both gas- and aerosol-phase tracers to a study carried out at Olympia-Lacey in Washington. In this study, three types of …


Estimation Of Cumulative Incidence Functions In Competing Risks Studies Under An Order Restriction, Hammou El Barmi, Subhash C. Kochar, Hari Mukerjee, Francisco J. Samaniego Jan 2003

Estimation Of Cumulative Incidence Functions In Competing Risks Studies Under An Order Restriction, Hammou El Barmi, Subhash C. Kochar, Hari Mukerjee, Francisco J. Samaniego

Mathematics and Statistics Faculty Publications and Presentations

In the competing risks problem an important role is played by the cumulative incidence function (CIF), whose value at time t is the probability of failure by time t for a particular type of failure in the presence of other risks. Its estimation and asymptotic distribution theory have been studied by many. In some cases there are reasons to believe that the CIFs due to two types of failure are order restricted. Several procedures have appeared in the literature for testing for such orders. In this paper we initiate the study of estimation of two CIFs subject to a type …


Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.1, Thomas M. Cole, Scott A. Wells Jan 2003

Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.1, Thomas M. Cole, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

CE-QUAL-W2 is a two-dimensional, longitudinal/vertical, hydrodynamic and water quality model. Because the model assumes lateral homogeneity, it is best suited for relatively long and narrow waterbodies exhibiting longitudinal and vertical water quality gradients. The model has been applied to rivers, lakes, reservoirs, estuaries, and combinations thereof.

The application of CE-QUAL-W2 requires knowledge in the following areas: 1. Hydrodynamics 2. Aquatic biology 3. Aquatic chemistry 4. Numerical methods 5. Computers and FORTRAN coding 6. Statistics 7. Data assembly and reconstruction.

Water quality modeling is in many ways an art requiring not only knowledge in these areas but also experience in their …


Solving Chemical Problems Of Environmental Importance Using Cavity Ring-Down Spectroscopy, Dean B. Atkinson Jan 2003

Solving Chemical Problems Of Environmental Importance Using Cavity Ring-Down Spectroscopy, Dean B. Atkinson

Chemistry Faculty Publications and Presentations

Cavity ring-down (CRD) is a sensitive variant of traditional absorption spectroscopy that has found increasing use in a number of chemical measurement applications. This review focuses on applications of cavity ring-down spectroscopy that will be of interest to environmental chemists and analytical chemists working on environmental problems. The applications are classified into direct monitoring approaches, indirect analysis methods and ancillary studies and a differentiation is made between field-tested instruments and proof of principle studies.


Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, John E. Barrett, Peter T. Doran, Andrew G. Fountain, W. Berry Lyons, Andrew N. Parsons, Dorota L. Porazinska, Ross A. Virginia, Diana H. Wall Jan 2003

Snow-Patch Influence On Soil Biogeochemical Processes And Invertebrate Distribution In The Mcmurdo Dry Valleys, Antarctica, Michael N. Gooseff, John E. Barrett, Peter T. Doran, Andrew G. Fountain, W. Berry Lyons, Andrew N. Parsons, Dorota L. Porazinska, Ross A. Virginia, Diana H. Wall

Geography Faculty Publications and Presentations

The McMurdo Dry Valleys is the largest of the ice-free areas in Antarctica. Precipitation events in excess of 1 cm of snow accumulation are rare. During the winter, snow is transported by strong katabatic winds blowing from the polar plateau, and deposited into the lee of topographic features (e.g., stream channels and other topographic depressions). At the start of the austral summer (early October), as much as 10% of the valley soils may be covered by distributed snow patches. Because liquid water is the primary driver of biological, physical, and chemical processes in this polar desert, quantifying fluxes of water …


A Multilevel Discontinuous Galerkin Method, Jay Gopalakrishnan, Guido Kanschat Jan 2003

A Multilevel Discontinuous Galerkin Method, Jay Gopalakrishnan, Guido Kanschat

Mathematics and Statistics Faculty Publications and Presentations

A variable V-cycle preconditioner for an interior penalty finite element discretization for elliptic problems is presented. An analysis under a mild regularity assumption shows that the preconditioner is uniform. The interior penalty method is then combined with a discontinuous Galerkin scheme to arrive at a discretization scheme for an advection-diffusion problem, for which an error estimate is proved. A multigrid algorithm for this method is presented, and numerical experiments indicating its robustness with respect to diffusion coefficient are reported.


A Schwarz Preconditioner For A Hybridized Mixed Method, Jay Gopalakrishnan Jan 2003

A Schwarz Preconditioner For A Hybridized Mixed Method, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

In this paper, we provide a Schwarz preconditioner for the hybridized versions of the Raviart-Thomas and Brezzi-Douglas-Marini mixed methods. The preconditioner is for the linear equation for Lagrange multipliers arrived at by eliminating the ux as well as the primal variable. We also prove a condition number estimate for this equation when no preconditioner is used. Although preconditioners for the lowest order case of the Raviart-Thomas method have been constructed previously by exploiting its connection with a nonconforming method, our approach is different, in that we use a new variational characterization of the Lagrange multiplier equation. This allows us to …


Ordering Genetic Algorithm Genomes With Reconstructability Analysis, Stephen Shervais, Martin Zwick Jan 2003

Ordering Genetic Algorithm Genomes With Reconstructability Analysis, Stephen Shervais, Martin Zwick

Systems Science Faculty Publications and Presentations

The building block hypothesis implies that genetic algorithm effectiveness is influenced by the relative location of epistatic genes on the chromosome. We find that this influence exists, but depends on the generation in which it is measured. Early in the search process it may be more effective to have epistatic genes widely separated. Late in the search process, effectiveness is improved when they are close together. The early search effect is weak but still statistically significant; the late search effect is much stronger and plainly visible. We demonstrate both effects with a set of simple problems, and show that infonnation-theoretic …


Under The Plastic: A Quantitative Look At Dvd Video Encoding And Its Impact On Video Modeling, Wu-Chi Feng, Jin Choi, Wu-Chang Feng, Jonathan Walpole Jan 2003

Under The Plastic: A Quantitative Look At Dvd Video Encoding And Its Impact On Video Modeling, Wu-Chi Feng, Jin Choi, Wu-Chang Feng, Jonathan Walpole

Computer Science Faculty Publications and Presentations

In this paper, we examine the DVD encoding process and the implications this process has video modeling and network traffic analysis. We have assembled a system that allows us to extract the video data from the DVDs as they were encoded for distribution. Analyzing the resulting video trace data, we describe how DVD encodings have evolved over time. In addition, our findings show that the underlying video content is fundamentally different than those produced by basic consumer video capture boards. We demonstrate how this affects current video modeling proposals and their affect on network traffic characterization. This research is based …


Anisotropic Ice Flow Leading To The Onset Of Ice Stream D, West Antarctica: Numerical Modelling Based On The Observations From Byrd Station Borehole, Weili Wang, H. Jay Zwally, Christina L. Hulbe, Martin J. Siegert, Ian R. Joughin Jan 2003

Anisotropic Ice Flow Leading To The Onset Of Ice Stream D, West Antarctica: Numerical Modelling Based On The Observations From Byrd Station Borehole, Weili Wang, H. Jay Zwally, Christina L. Hulbe, Martin J. Siegert, Ian R. Joughin

Geology Faculty Publications and Presentations

An ice-sheet flowline model is used to simulate the flow of ice along two particle paths toward the onset to Ice Stream D,West Antarctica. One path is near the centre line of the main tributary to the ice stream, while the second passes by the Byrd Station borehole site. In this paper, we analyze the flow of the moderately fast-flowing tributaries in terms of ice-fabric anisotropy and estimate the steady-state ice-flow regions with the compatible developed crystal orientation fabrics along two particle paths. Comparison between modelled isochrones and internal layers detected from radio-echo sounding surveys in the area is used …


Investigating The Urban Heat Island Effect With A Collaborative Inquiry Project, Linda Acha George, William G. Becker Jan 2003

Investigating The Urban Heat Island Effect With A Collaborative Inquiry Project, Linda Acha George, William G. Becker

Environmental Science and Management Faculty Publications and Presentations

Modification of the earth's surface through urbanization can have a dramatic impact on local climate. A phenomenon known as the Urban Heat Island (UHI) effect, which is a measure of the near-surface air temperature contrast between urbanized and adjoining rural areas, can be evaluated with readily available instruments. Students in an undergraduate general education science course study this phenomenon in the Portland, Oregon area through a collaborative research project. This inquiry project includes background content and literature review, preliminary studies, development of research questions, experimental design and implementation, data analysis and report writing. This project successfully enables students to collaboratively …


Valley Floor Climate Observations From The Mcmurdo Dry Valleys, Antarctica, 1986-2000, Peter T. Doran, Christopher P. Mckay, Gary D. Clow, Gayle L. Dana, Andrew G. Fountain, Thomas H. Nylen, W. Berry Lyons Dec 2002

Valley Floor Climate Observations From The Mcmurdo Dry Valleys, Antarctica, 1986-2000, Peter T. Doran, Christopher P. Mckay, Gary D. Clow, Gayle L. Dana, Andrew G. Fountain, Thomas H. Nylen, W. Berry Lyons

Geography Faculty Publications and Presentations

Climate observations from the McMurdo dry valleys, East Antarctica are presented from a network of seven valley floor automatic meteorological stations during the period 1986 to 2000. Mean annual temperatures ranged from −14.8°C to −30.0°C, depending on the site and period of measurement. Mean annual relative humidity is generally highest near the coast. Mean annual wind speed increases with proximity to the polar plateau. Site to site variation in mean annual solar flux and PAR is due to exposure of each station and changes over time are likely related to changes in cloudiness. During the non-summer months, strong katabatic winds …


Report On The Oregon Ballast Water Management Program In 2002, Jordan Vinograd, Mark Sytsma Dec 2002

Report On The Oregon Ballast Water Management Program In 2002, Jordan Vinograd, Mark Sytsma

Center for Lakes and Reservoirs Publications and Presentations

This report documents the efficacy of the first ten months of the Oregon Ballast Water Management Program, which was established by SB 895 during the 2001 legislative session. The Oregon Ballast Water Management Program was initiated to address the introduction of aquatic nuisance species via discharge of ballast water from ships. The Program reflects the Oregon Legislature’s recognition of the potential for aquatic nuisance species to cause economic and environmental damage to the State. Oregon Laws 2001, Chapter 722 (Appendix A), required that owners and operators of certain vessels entering Oregon waters must report the time and place ballast water …


Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells Dec 2002

Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:

• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam for 2001 based on the calibration conducted for 1991 and 2000 data sets, (Annear et al, 2001).

• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen …


Multi-Level Decomposition Of Probalistic Relations, Stanislaw Grygiel, Martin Zwick, Marek Perkowski Dec 2002

Multi-Level Decomposition Of Probalistic Relations, Stanislaw Grygiel, Martin Zwick, Marek Perkowski

Systems Science Faculty Publications and Presentations

Two methods of decomposition of probabilistic relations are presented in this paper. They consist of splitting relations (blocks) into pairs of smaller blocks related to each other by new variables generated in such a way so as to minimize a cost function which depends on the size and structure of the result. The decomposition is repeated iteratively until a stopping criterion is met. Topology and contents of the resulting structure develop dynamically in the decomposition process and reflect relationships hidden in the data.


A Performance Study Of Lam And Mpich On An Smp Cluster, Brian Patrick Kearns Dec 2002

A Performance Study Of Lam And Mpich On An Smp Cluster, Brian Patrick Kearns

Dissertations and Theses

Many universities and research laboratories have developed low cost clusters, built from Commodity-Off-The-Shelf (COTS) components and running mostly free software. Research has shown that these types of systems are well-equipped to handle many problems requiring parallel processing. The primary components of clusters are hardware, networking, and system software. An important system software consideration for clusters is the choice of the message passing library.

MPI (Message Passing Interface) has arguably become the most widely used message passing library on clusters and other parallel architectures, due in part to its existence as a standard. As a standard, MPI is open for anyone …


Modified Bell-Plesset Effect With Compressibility: Application To Double-Shell Ignition Target Designs, Peter A. Amendt, J. D. Colvin, John D. Ramshaw, H. F. Robey, O. L. Landen Nov 2002

Modified Bell-Plesset Effect With Compressibility: Application To Double-Shell Ignition Target Designs, Peter A. Amendt, J. D. Colvin, John D. Ramshaw, H. F. Robey, O. L. Landen

Physics Faculty Publications and Presentations

The effect of spherical convergence on the fluid stability of collapsing and expanding bubbles was originally treated by Bell [Los Alamos Scientific Laboratory Report No. LA-1321 (1951)] and Plesset [J. Appl. Phys. 25, 96 (1954)]. The additional effect of fluid compressibility was also considered by Bell but was limited to the case of nonzero density on only one side of a fluid interface. A more general extension is developed which considers distinct time-dependent uniform densities on both sides of an interface in a spherically converging geometry. A modified form of the velocity potential is used that avoids an unphysical divergence …


High Frequency-Bandwidth Optical Technique To Measure Thermal Elongation Time Responses Of Near-Field Scanning Optical Microscopy Probes, Andres H. La Rosa, B. Biehler Nov 2002

High Frequency-Bandwidth Optical Technique To Measure Thermal Elongation Time Responses Of Near-Field Scanning Optical Microscopy Probes, Andres H. La Rosa, B. Biehler

Physics Faculty Publications and Presentations

A near-field scanning optical microscopy (NSOM) probe elongates when light is coupled into it. The time response of this thermal process is measured here by a new optical technique that exploits the typical flat-apex morphology of the probe as a mirror in a Fabry-Perot type cavity. Pulsed laser light is coupled into the probe to heat up the tip, while another continuous wave laser serves to monitor the elongation from the interference pattern established by the reflections from the flat-apex probe and a semitransparent metal-coated flat sample. A quarter wave plate is introduced into the interferometer optical path in order …