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Articles 3361 - 3390 of 3797

Full-Text Articles in Physical Sciences and Mathematics

Electrolysis Of Palladium In Heavy Water, Christoph Zaczek Jul 1995

Electrolysis Of Palladium In Heavy Water, Christoph Zaczek

Dissertations and Theses

Following several reports in the past few years about compositional changes on palladium used as a cathode in heavy water electrolysis, the purpose of this research project was to reproduce this results.

Two experiments were performed using two cells connected in series, an experimental cell and a control cell.

Both experiments used platinum anodes, the experimental cell had a palladium cathode and the control cell had a platinum cathode. The electrolyte was D2O with H2SO4. Radiation was monitored during both experiments. Also temperature and voltage were recorded for both experiments, to allow statements about …


Electrolysis Of Titanium In Heavy Water, Radovan Kopecek Jun 1995

Electrolysis Of Titanium In Heavy Water, Radovan Kopecek

Dissertations and Theses

The purpose of these studies was to determine if results similar to those of Fleischmann and Pons could be obtained using a titanium cathode instead of palladium in an electrolysis in a heavy water cell. The electrolyte consists of D2O and H2SO4. Two experiments have been performed to examine the features of this electrolysis. As titanium shows the same properties to attract hydrogen, it seemed possible that excess heat could be produced. Radiation was monitored, and the surface of the titanium cathode was examined before and after electrolysis for any changes in the morphology …


The Distribution Of Naturally Occurring Soil Radionuclides And Radon Potential Of Northwest Oregon, Stuart Graham Ashbaugh Jun 1995

The Distribution Of Naturally Occurring Soil Radionuclides And Radon Potential Of Northwest Oregon, Stuart Graham Ashbaugh

Dissertations and Theses

Radon, a naturally occurring radioactive gas produced as one of the decay products of soil/rock uranium and thorium, is considered to be a leading cause of pulmonary disease. Gamma spectrometry of 146 samples of soil were used to quantify radon source potential relative to lithology by measuring Bi214 activity of the U238 decay series. Additional soil radio nuclide data (Th232, Ac228, K40 and C137 ) were used to help identify regional source provenance geochemistry and soil development. Ac228, Bi214 and Th232 activities in northwest Oregon soils range from five …


Synthesis And Characterization Of A Porphyrin Dyad, Dale A. Braden Jun 1995

Synthesis And Characterization Of A Porphyrin Dyad, Dale A. Braden

Dissertations and Theses

The sun is a bountiful source of energy for our planet. .With the advent of photovoltaic cells, man has begun harnessing the sun's radiant energy, turning it into a form more directly useful: electricity. Commercially available solar cells currently operate at about 13% efficiency, sufficiently high to make them a viable source of electrical energy. It is of great interest, however, to improve their conversion efficiency, and to lower the cost of production so as to make them more economical, and thereby reduce our dependence upon traditional "dirty" sources of energy such as coal and oil. It has been found …


Modeling Of Decay Rate For Molecules At An Island Surface, Ting Xiong Jun 1995

Modeling Of Decay Rate For Molecules At An Island Surface, Ting Xiong

Dissertations and Theses

The decay rates for molecules at rough surfaces are studied via an island surface model, with particular emphasis on the effect due to the distribution of surface roughness. Two extreme cases are studied when the surface islands distribute themselves evenly and when they coalesce to form local clusters at the molecule-substrate interface. The optical properties of the interfacial layer in these two cases are described by the Maxwell-Garnett and the fractal-cluster models, respectively. Among other results, it is found that both enhancement and suppression of the surface-induced decay rates are possible due to the presence of roughness, with more dramatic …


Fast Byte Copying: A Re-Evaluation Of The Opportunities For Optimization, Jon Inouye, Jonathan Walpole, Ke Zhang Jun 1995

Fast Byte Copying: A Re-Evaluation Of The Opportunities For Optimization, Jon Inouye, Jonathan Walpole, Ke Zhang

Computer Science Faculty Publications and Presentations

High-performance byte copying is important for many operating systems because it is the principle method used for transferring data between kernel and user protection domains. For example, byte copying is commonly used for transferring data from kernel buffers to user buffers during file system read and IPC recv calls and to kernel buffers from user buffers during 'Write and-send calls. Because of its impact on overall system performance, commercial operating systems tend to employ many specialized byte copy routines, each one optimized for a different circumstance.

This paper revisits the opportunities for optimizing byte copy performance by discussing a series …


A Hydrologic Analysis Of Government Island, Oregon, Scott Gregory Bittinger May 1995

A Hydrologic Analysis Of Government Island, Oregon, Scott Gregory Bittinger

Dissertations and Theses

Government Island, located in the Columbia River approximately 16 km (10 mi) upstream of the confluence with the Willamette River, is a wetland mitigation site prompted by expansion of the southwest quadrant of Portland International Airport. The purpose of the study is to predict water levels in two enclosed lowland areas, Jewit Lake and Southeast Pond, based on levels of the Columbia River, precipitation, and evapotranspiration. Mitigation is intended to convert 1.13 km2 (237 acres) of seasonally flooded wetland to 1.27 km2 (267 acres) of semi-permanently flooded wetland and seasonally flooded wetland. Flooding of the wetland is most likely to …


The Parser Converter Loader: An Implementation Of The Computational Chemistry Output Language (Ccol), Donald Randall Abel May 1995

The Parser Converter Loader: An Implementation Of The Computational Chemistry Output Language (Ccol), Donald Randall Abel

Dissertations and Theses

A necessity of managing scientific data is the ability to maintain experimental legacy information without continually modifying the applications that create and use that information. By facilitating the management of scientific data we hope to give scientists the ability to effectively use additional modeling applications and experimental data. We have demonstrated that an extensible interpreter, using a series of stored directives, allows the loading of data from computational chemistry applications into a generic database. Extending the interpreter to support a new application involves supplying a list of directives for each piece of information to be loaded. This research confirms that …


Differentiable Circle Maps With A Flat Interval, J. Graczyk, L. B. Jonker, G. Swiatek, F. M. Tangerman, J. J. P. Veerman May 1995

Differentiable Circle Maps With A Flat Interval, J. Graczyk, L. B. Jonker, G. Swiatek, F. M. Tangerman, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We study weakly order preserving circle maps with a flat interval, which are differentiable even on the boundary of the flat interval. We obtain estimates on the Lebesgue measure and the Hausdorff dimension of the non-wandering set. Also, a sharp transition is found from degenerate geometry to bounded geometry, depending on the degree of the singularities at the boundary of the flat interval.


Mist: Pvm With Transparent Migration And Checkpointing, Jeremy Casas, Dan Clark, Phil Galbiati, Ravi Konuru, Steve Otto, Robert Prouty, Jonathan Walpole May 1995

Mist: Pvm With Transparent Migration And Checkpointing, Jeremy Casas, Dan Clark, Phil Galbiati, Ravi Konuru, Steve Otto, Robert Prouty, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We are currently involved in research to enable PVM to take advantage of shared networks of workstations (NOWs) more effectively. In such a computing environment, it is important to utilize workstations unobtrusively and recover from machine failures. Towards this goal, we have enhanced PVM with transparent task migration, checkpointing, and global scheduling. These enhancements are part of the MIST project which takes an open systems approach in developing a cohesive, distributed parallel computing environment. This open systems approach promotes plug-and-play integration of independently developed modules, such as Condor, DQS, A VS, Prospero, XPVM, PIOUS, Ptools, etc. Transparent task migration, in …


Fage Determination Of Tropospheric Ho And Ho₂, Linda Acha George, Thomas M. Hard, Robert J. O'Brien Apr 1995

Fage Determination Of Tropospheric Ho And Ho₂, Linda Acha George, Thomas M. Hard, Robert J. O'Brien

Environmental Science and Management Faculty Publications and Presentations

FAGE (fluorescence assay with gas expansion) was developed as a sensitive technique for the detection of low-concentration free radicals in the atmosphere. The application of FAGE to tropospheric hydroxyl (H0) and hydroperoxyl (H0₂) radicals has yielded calibrated measurements of both species in both clean air and highly polluted urban air. For HO calibration, a continuously stirred tank reactor provides a uniform external HO concentration, which can be measured by gas chromatography of an HO-reactive hydrocarbon. The aerodynamics of the air-sampling process has been modeled computationally, with results that agree with empirical observations of the effects of nozzle diameter on HO …


Evolving Globally Synchronized Cellular Automata, Rajarshi Das, James P. Crutchfield, Melanie Mitchell, James M. Hanson Apr 1995

Evolving Globally Synchronized Cellular Automata, Rajarshi Das, James P. Crutchfield, Melanie Mitchell, James M. Hanson

Computer Science Faculty Publications and Presentations

How does an evolutionary process interact with a decentralized, distributed system in order to produce globally coordinated behavior? Using a genetic algorithm (GA) to evolve cellular automata (CAs), we show that the evolution of spontaneous synchronization, one type of emergent coordination, takes advantage of the underlying medium's potential to form embedded particles. The particles, typically phase defects between synchronous regions, are designed by the evolutionary process to resolve frustrations in the global phase. We describe in detail one typical solution discovered by the GA, delineating the discovered synchronization algorithm in terms of embedded particles and their interactions. We also use …


Mpvm: A Migration Transparent Version Of Pvm, Jeremy Casas, Dan Clark, Ravi Konuru, Steve Otto, Robert Prouty, Jonathan Walpole Apr 1995

Mpvm: A Migration Transparent Version Of Pvm, Jeremy Casas, Dan Clark, Ravi Konuru, Steve Otto, Robert Prouty, Jonathan Walpole

Computer Science Faculty Publications and Presentations

Parallel Virtual Machine (PVM) is a widely-used software system that allows a heterogeneous set of parallel and serial UNIX-based computers to be programmed as a single message-passing parallel machine, In this paper, an extension to PVM to support dynamic process migration is presented. Support for migration is important in general-purpose workstation environments since it allows parallel computations to co-exist with other applications, using idle-cycles as they become available and off-loading from workstations when they are no longer free. A description and evaluation of the design and implementation of the prototype Migratable PVM system is presented together with some performance results.


Psusort: A Parallel External Sort For A Shared Memory Multiprocessor System, Sujata V. Ramamoorthy Feb 1995

Psusort: A Parallel External Sort For A Shared Memory Multiprocessor System, Sujata V. Ramamoorthy

Dissertations and Theses

A method to parallelize external sorts on a shared memory multiprocessing system is presented in this thesis. The main goal of the thesis is to develop a sorting package that is scale able and efficient. No prior knowledge of the nature, source or size of the data is assumed for this work. A dynamic load-balancing architecture is used with no static allocation of tasks to processes. The package consists of an interface and a kernel. The interface provides the sort with the following - the sort input, output and temporary work spaces as abstract data types (ADTs), memory available, number …


Molecular Fluorescence Spectroscopy In The Vicinity Of A Microstructure, P.T. Leung, Thomas F. George Jan 1995

Molecular Fluorescence Spectroscopy In The Vicinity Of A Microstructure, P.T. Leung, Thomas F. George

Physics Faculty Publications and Presentations

A brief review is presented on fluorescence spectroscopy of molecules in the vicinity of a microstructure, which could be a surface structure, clustered ions/atoms, a colloidal particle in a solution, or a tip in certain molecular probes. This structure can be viewed as microscopic, mesoscopic or macroscopic, depending on the specific environment in which the molecule is located. An overview is given for selected experimental and theoretical aspects of this phenomenon, emphasizing some of the previous modeling work of the authors. Discussion of possible future attempts to explore the phenomenon in more detail is presented at the end.


Intersecting Self-Similar Cantor Sets, J. J. P. Veerman Jan 1995

Intersecting Self-Similar Cantor Sets, J. J. P. Veerman

Mathematics and Statistics Faculty Publications and Presentations

We define a self-similar set as the (unique) invariant set of an iterated function system of certain contracting affine functions. A topology on them is obtained (essentially) by inducing the C 1- topology of the function space. We prove that the measure function is upper semi-continuous and give examples of discontinuities. We also show that the dimension is not upper semicontinuous. We exhibit a class of examples of self-similar sets of positive measure containing an open set. If C 1 and C 2 are two self-similar sets C 1 and C 2 such that the sum of their dimensions …


Scheduling Of Parallel Jobs On Dynamic, Heterogenous Networks, Dan Clark, Jeremy Casas, Steve Otto, Robert Prouty, Jonathan Walpole Jan 1995

Scheduling Of Parallel Jobs On Dynamic, Heterogenous Networks, Dan Clark, Jeremy Casas, Steve Otto, Robert Prouty, Jonathan Walpole

Computer Science Faculty Publications and Presentations

In using a shared network of workstations for parallel processing, it is not only important to consider heterogeneity and differences in processing power between the workstations but also the dynamics of the system as a whole. In such a computing environment where the use of resources vary as other applications consume and release resources, intelligent scheduling of the parallel jobs onto the available resources is essential to maximize resource utilization. Despite this realization, however, there are few systems available that provide an infrastructure for the easy development and testing of these intelligent schedulers. In this paper, an infrastructure is presented …


Set-Theoretic Reconstructability Of Elementary Cellular Automata, Martin Zwick, Hui Shu Jan 1995

Set-Theoretic Reconstructability Of Elementary Cellular Automata, Martin Zwick, Hui Shu

Systems Science Faculty Publications and Presentations

Set-theoretic reconstructability analysis is used to characterize the structures of the mappings of elementary cellular automata. The minimum complexity structure for each ECA mapping, indexed by parameter σ, is more effective than the λ parameter of Langton as a predictor of chaotic dynamics.


Towards An Ontology Of Problems, Martin Zwick Jan 1995

Towards An Ontology Of Problems, Martin Zwick

Systems Science Faculty Publications and Presentations

Systems theory offers a language in which one might formulate a metaphysics (or more specifically an ontology) of problems. This proposal is based upon a conception of systems theory shared by von Bertalanffy, Wiener, Boulding, Rapoport, Ashby, Klir, and others, and expressed succinctly by Bunge, who considered game theory, information theory, feedback control theory, and the like to be attempts to construct an "exact and scientific metaphysics." Our prevailing conceptions of "problems" are concretized yet also fragmented and in fact dissolved by the standard reductionist model of science, which cannot provide a general framework for analysis. The idea of a …


Optimizing Object Invocation Using Optimistic Incremental Specialization, Jon Inouye, Andrew P. Black, Charles Consel, Calton Pu, Jonathan Walpole Jan 1995

Optimizing Object Invocation Using Optimistic Incremental Specialization, Jon Inouye, Andrew P. Black, Charles Consel, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

To make object invocation efficient, it is important to minimize overhead. In general, overhead is incurred in order to maintain transparency; with the advent of mobile computer systems, persistence, increasing security and privacy concerns, transparency becomes more expensive and overhead is increasing. Invocation mechanisms maintain transparency by finding objects, choosing communication media, performing data translation into common formats (e.g., XDR), marshalling arguments, encrypting confidential data, etc. Performing all of these operations on every invocation would lead to unacceptable performance, so designers often avoid operations by specializing object invocation for more restricted environments. For example, the Emerald compiler performs several optimizations …


Monomeric And Polymeric Fluoroalkyl Sulfonyl Fluorides, Sulfonate Salts And Sulfonic Acids For Use As Electrolytes And Coatings, Nicolas Noel Hamel Jan 1995

Monomeric And Polymeric Fluoroalkyl Sulfonyl Fluorides, Sulfonate Salts And Sulfonic Acids For Use As Electrolytes And Coatings, Nicolas Noel Hamel

Dissertations and Theses

Monomeric and polymeric fluoroalkyl sulfonyl fluorides, sulfonate salts and sulfonic acids have qualities desirable for use as electrolytes in alternative energy sources such as fuel cells and solid polymer electrolyte lithium batteries. Since the nature of the fluoroalkyl group affects the properties of these compounds, new monomeric and polymeric fluoroalkyl sulfonyl fluorides, sulfonate salts and sulfonic acids were prepared in this work. Simple compounds prepared in this work were: the fluoroalkyl sulfonyl fluorides, sulfonate salts and sulfonic acid CHF (OCF₂CF2SO₂ F)₂ CF₂(OCF₂CF₂SO₂F) ₂ CH₂(OCF₂CF₂SO3Na) ₂ CF₂(OCF₂CF₂SO3 ) ₂Ca , CF₂(OCF₂CF₂SO3H) ₂ prepared by means of electrochemical fluorination; FC (CF3 ) …


Some Relationships Between Sedimentary Trace Metal Concentrations And Freshwater Phytoplankton And Sedimentary Diatom Species Composition, Allan Hayes Vogel Jan 1995

Some Relationships Between Sedimentary Trace Metal Concentrations And Freshwater Phytoplankton And Sedimentary Diatom Species Composition, Allan Hayes Vogel

Dissertations and Theses

Sediments from 21 Oregon lakes were analyzed for seven metals (Fe, Mn, Zn, Cu, Co, Ni, V) in three forms (exchangeable, organic+sulfides, and oxyhydroxides+ oxides+ carbonates) using a sequential fractionation procedure. The summer epilimnetic filterable concentration of an eighth (Mo) was also determined. Sedimentary diatom remains and summer phytoplankton populations of the lakes were correlated with the 22 metal parameters and with conservative water chemistry parameters, estimators of lake productivity, and watershed geology. Both the sedimentary metals and the two populations of primary producers correlated best with the ecoregions of Omernik and Gallant (1986). A number of species possessed correlations …


Logging Subsystem Performance: Model And Evaluation, Thomas K. Clark Oct 1994

Logging Subsystem Performance: Model And Evaluation, Thomas K. Clark

Dissertations and Theses

Transaction logging is an integral part of ensuring proper transformation of data from one state to another in modern data management. Because of this, the throughput of the logging subsystem can be critical to the throughput of an application. The purpose of this research is to break the log bottleneck at minimum cost. We first present a model for evaluating a logging subsystem, where a logging subsystem is made up of a log device, a log backup device, and the interconnect algorithm between the two, which we term the log backup method. Included in the logging model is a set …


Landslide Inventory And Susceptibility Mapping Of The Upper Canyon Creek Basin, Cascade Range, Skamania County, Washington, Lawrence P. Growney Oct 1994

Landslide Inventory And Susceptibility Mapping Of The Upper Canyon Creek Basin, Cascade Range, Skamania County, Washington, Lawrence P. Growney

Dissertations and Theses

Contact relations, and bedrock and overburden characteristics for approximately 8100 ha of the upper Canyon Creek basin, Skamania County, Washington, have been assessed in order to determine the causes and extent of failures and to assign slope failure susceptibilities to the area. The study area is located in the western Cascade Range on land administered by the Gifford Pinchot National Forest. Clear-cutting over the past 30 years has impacted between 50% to 80% of the study area. The total surface area occupied by failure deposits (198.6 ha) is less than 2.5% of the study area. Failures occur by one of …


The Geology Of Parrett Mountain, Oregon, And Its Influences On The Local Groundwater Systems, Brett Todd Brodersen Sep 1994

The Geology Of Parrett Mountain, Oregon, And Its Influences On The Local Groundwater Systems, Brett Todd Brodersen

Dissertations and Theses

A geologic study of the Parrett Mountain area, located twenty miles (32 kms) south-southwest of Portland, Oregon, was initiated by the Oregon Water Resources Department. The main goal was to create a stratigraphic and structural model of Parrett Mountain in order to better understand the local basalt aquifers present there. Previous geologic studies of the area revealed the mountain to be composed of Columbia River basalt. Field mapping and hand lithologic and geochemical analyses allowed the basalt to be subdivided into eleven basalt flows. These flows are as follows: (from oldest to youngest) the Wapshilla Ridge (WpR) , the Ortley-Grouse …


Sediment Yield Analysis Of Reservoir #1, Bull Run Watershed, West Cascade Mountains, Oregon, Doann M. Hamilton Sep 1994

Sediment Yield Analysis Of Reservoir #1, Bull Run Watershed, West Cascade Mountains, Oregon, Doann M. Hamilton

Dissertations and Theses

Bull Run Watershed was set aside in late the 1800s as the water supply source for the City of Portland. Other than two dams being constructed, Reservoir #1 (1929) and Reservoir #2 (1962), development of the land had been minimal as public access was restricted. In the early 1960s, land management changed with increased road building and timber removal raising concerns about increased sediment discharge into the reservoirs. The objective of this study is to evaluate how much and how fast the sediment has accumulated in Reservoir #1, and to determine if the rate of sediment accumulation has changed over …


Objects To The Rescue! Or Httpd: The Next Generation Operating System, Andrew P. Black, Jonathan Walpole Sep 1994

Objects To The Rescue! Or Httpd: The Next Generation Operating System, Andrew P. Black, Jonathan Walpole

Computer Science Faculty Publications and Presentations

This position paper suggests that object-oriented operating systems may provide the means to meet the ever-growing demands of applications. As an example of a successful OOOS, we cite the http daemon. To support the contention that httpd is in fact an operating system, we observe that it implements uniform naming, persistent objects and an invocation meta-protocol, specifies and implements some useful objects, and provides a framework for extensibility.We also believe that the modularity that is characteristic of OO systems should provide a performance benefit rather than a penalty. Our ongoing work in the Synthetix project at OGI is exploring the …


Studies In Fluorine Chemistry: 13c Nmr Investigation Of Sf5/So2f Fluorinated Systems, Yoon S. Choi Aug 1994

Studies In Fluorine Chemistry: 13c Nmr Investigation Of Sf5/So2f Fluorinated Systems, Yoon S. Choi

Dissertations and Theses

The purpose of this thesis was two fold: (i) The synthesis and characterization of SF5 containing dienes. (ii) The characterization of hydro/fluorocarbon compounds containing SF5/S02F groups via their 13C NMR spectra. A new SF5CH2CHBrCH2CF=CF2 was prepared and characterized as a precursor to new dielectric polymers. This new adduct was made from the reaction of pentafluorothio bromide with l,l,2-trifluoro-1,4-pentadiene. A SF5-diene was prepared from the reaction of pentafluorothio chloride with acetylene. This reaction involves a radical addition mechanism. The SF5 group is bonded to the carbon atom carrying the most hydrogens. SF5 - dienes are capable of undergoing different reactions, such …


Coastal Crossing Of The Elastic Strain Zero-Isobase, Cascadia Margin, South Central Oregon Coast, Gregory George Briggs Aug 1994

Coastal Crossing Of The Elastic Strain Zero-Isobase, Cascadia Margin, South Central Oregon Coast, Gregory George Briggs

Dissertations and Theses

The analysis of marsh cores from the tidal zones of the Siuslaw, Umpqua, and Coos River systems on the south-central Oregon coast provides supporting evidence of coseismic subsidence resulting from megathrust earthquakes and reveals the landward extent of the zero-isobase. The analysis is based on lithostratigraphy, paleotidal indicators, microfossil paleotidal indicators, and radiocarbon age. Coseismic activity is further supported by the presence of anomalous thin sand layers present in certain cores. The analysis of diatom assemblages provides evidence of relative sea-level displacement on the order of 1 to 2 m. The historic quiescence of local synclinal structures in the Coos …


Building Of A Thermoacoustic Refrigerator And Measuring The Basic Performance, Torsten Blumreiter Jul 1994

Building Of A Thermoacoustic Refrigerator And Measuring The Basic Performance, Torsten Blumreiter

Dissertations and Theses

The application of thermoacoustic phenomena for cooling purposes has a comparatively short history. However, recent experiments have shown that thermoacoustic refrigeration can achieve practical significance for both every day cooling in households and cryocooling for scientific purposes due to its high reliability, environmental safety and functioning under extreme conditions.

We build a thermoacoustic refrigerator driven by a commercial loudspeaker. It was equipped with a vacuum pump and an entrance port for introducing different gases under different pressures as working fluids. It contained two thermocouples and a pressure transducer for quantitative measurements of the basic performance. The resonance frequency of the …