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Beam Propagation In Parabolically Tapered Graded-Index Waveguides, Anthony A. Tovar, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

To a good approximation, the electromagnetic-propagation characteristics of graded-index waveguides can be written in terms of polynomial-Gaussian modes. For uniform quadratic-index waveguides the behavior of these modes is well known. However, there are sometimes practical reasons for using tapered waveguides, but detailed propagation solutions are known for only a few specific taper functions. The parabolic taper is perhaps the most important special case, and the solution-generating techniques that we generalize are used to obtain analytic solutions for this case.

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

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 …

Reflection And Refraction Of Light From Nonlinear Boundaries, Mohammad Azadeh

Dissertations and Theses

This thesis deals with the topic of reflection and refraction of light from the boundary of nonlinear materials in general, and saturating amplifiers in particular. We first study some of the basic properties of the light waves in nonlinear materials. We then develop a general formalism to model the reflection and refraction of light with an arbitrary angle of incidence from the boundary of a nonlinear medium. This general formalism is then applied to the case of reflection and refraction from the boundary of linear dielectrics. It will be shown that in this limit, it reduces to the well known …

Particle Trapping In Estuarine Tidal Flows, David A. Jay, Jeffery D. Musiak

Civil and Environmental Engineering Faculty Publications and Presentations

Particle trapping in estuarine turbidity maxima (ETM) is caused primarily by convergent mean and/or tidal fluxes of sediment. The result is an approximately bell-shaped along-channel distribution of vertically integrated, tidal cycle mean suspended sediment concentration. Observations from the Columbia River estuary suggest that (1) strong two-layer or internal along-channel residual and overtide flows are generated by time-varying stratification and (2) correlations between the near-bed velocity and the suspended sediment fields at these frequencies are important in landward transport of sediment. A new spatially and temporally integrated form of the sediment conservation equation has been derived to analyze this trapping process. …

Generalized Reverse Theorems For Multipass Applications In Matrix Optics, Lee W. Casperson, Anthony A. Tovar

Electrical and Computer Engineering Faculty Publications and Presentations

The reverse theorem that governs backward propagation through optical systems represented by transfer matrices is examined for various matrix theories. We extend several reverse theorems to allow for optical systems represented by matrices that may or may not be unimodular and that may be 2 × 2 or take on an augmented 3 × 3 form. As an example, we use the 3 × 3 form of the reverse theorem to study a laser with intracavity misaligned optics. It is shown that, by tilting one of the laser's mirrors, we can align the laser output arbitrarily, and the mirror tilt …

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 Creek …

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 …

Circuit Modeling Of Switched Linear Networks, Fardin Ansari

Dissertations and Theses

The use of switched linear networks is prevalent in power processing systems such as dc-to-dc power converters. These converters provide regulated dc output power and are widely used in the power supplies for computers and peripherals. As with most systems where high performance is a criterion, the power converter is usually enclosed in a feedback loop. Feedback design usually entails the use of small signal (linear) models with linear feedback design techniques. There exists a large number of small signal models, but most of them are ad hoc. A describing function approach has previously been presented which determines the exact …

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

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

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

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 …

Interfacing A Computer To A Scanning Tunneling Microscope, Markus Jarasch

Dissertations and Theses

A program was written in 'C' to control the functions of an already existing Scanning Tunneling Microscope (STM). A DAS-1601 data acquisition card (from Keithley Data Acquisition) was installed together with its drivers for 'C' on a computer with a 486-DX motherboard. The computer was interfaced to the electronics of the STM. Images taken of HOPG (highly oriented pyrolitic graphite) were of a reasonable quality and showed atomic resolution.

Electrophoretic Studies Of Ion Adsorption To Sarcoplasmic Reticulum And Phosphatidylcholine Membranes, Andreas Schilling

Dissertations and Theses

In this study, electrophoretic mobilities of native and two types of trypsin digested sarcoplasmic reticulum vesicles have been determined by microelectrophoresis using a Doppler Electrophoretic Light Scattering Analyzer to investigate the influence of hydrodynamic drag, caused by the Ca2⁺, Mg2⁺ -ATPase protruding from the surface of native sarcoplasmic reticulum vesicles. After the prolonged digestion (protein:trypsin ratio of 20 for 3 hours at 25°C), the ATPase was cleaved and removed from the sarcoplasmic reticulum membrane as shown with SDS gel electrophoresis and an ATPase activity assay. Ionic strength and pH dependence of mobility showed a nearly pH independent …

Interactions Of Ruthenium Red With Phospholipid Vesicles, Dirk Voelker

Dissertations and Theses

We have studied the electrostatic and other interactions of the inorganic, hexavalent dye Ruthenium Red (RR) with phospholipid vesicles composed of phosphatidylcholine (PC) and phosphatidylserine (PS) or phosphatidylinositol (Pl) in various mixtures and concentrations. Experiments were based on spectrophotometric absorption measurements which compared RR concentrations in the presence and in the absence of liposomes at different dye concentrations. Multilamellar liposomes were obtained by handshaken preparations. Five freeze-and-thaw cycles of the lipid-RR suspension produced an ion equilibrium distribution at the membrane-water interface. Results are given in terms of the Gouy-Chapman-Stem adsorption theory with the linear partition coefficient and a newly introduced …

Math Anxiety, Coping Behavior, And Gender, Sandra Joy Grossmann

Dissertations and Theses

Non-math majors enrolled in lower-division math courses at an urban university were surveyed on their math attitudes, coping behaviors, and math anxiety (MATHANX). The Revised Ways of Coping Checklist (RWCC), Revised Math Anxiety Rating Scale, and other questions were presented to 30 men and 32 women.

Hierarchical regressions showed that after controlling for attitudinal covariates, emotion-focused coping behaviors (EMOTFOC) were strongly associated with MATHANX (F(5,54)=18.66, p < .0001), but problem-focused coping behaviors (PROBFOC) were not. The RWCC subscale most highly correlated with MATHANX was Wishful Thinking (r = .70, p < .0001). Ss were then dichotomized on PROBFOC and EMOTFOC, providing four behavioral groups. An ANCOVA controlling for attitudinal covariates showed behavioral group membership significant with respect to MATHANX (F(3,58)=6.07, p < .001), and an ANOVA revealed that students who reported high EMOTFOC coupled with low PROBFOC experienced the greatest MATHANX (F(3,58) = 12.66, p < .0001).

Males and females reported virtually identical MATHANX (M=36.30 for males, 36.44 for females), and the only significant gender difference was for avoidance coping, which was used more by males (F(1,60) = 5.43, p < .03]. Results from this study suggest that fewer gender differences may exist in MATHANX and coping than have been found in the past. Additionally, this study identifies the need for future research to determine whether EMOTFOC is the behavioral component, or one of the determinants, of math anxiety.

1994 Commencement Program, A. Gary Ames

Commencement Archives 1990-99

The program for the Portland State University Spring Commencement ceremony on June 11, 1994.

A. Gary Ames, communications executive and Portland State alumnus, received an honorary degree and delivered the commencement address.

Smectic-A —Smectic-C* —Smectic-C Multicritical Point In Ferroelectric Liquid Crystals, Shankar B. Rananavare, V. G. K. M. Pisipati, E. W. Wong

Chemistry Faculty Publications and Presentations

We report a smectic-A–smectic-C–smectic-C* (ACC*) multicritical point in mixtures of chiral DOBAMBC [p-(n-decyloxybenzylidene)-p-amino-(2-methyl-butyl)] cinnamate and achiral 10O.8 (4-decyloxybenzylidene-4-octylaniline). Studies of the phase diagram, tilt angle (θ), polarization (P), and helix pitch (p) indicate an ACC* Lifshitz point that can be described in terms of the extended Landau theory. Specifically, the T*_AC and the maximum polarization (P_m) exhibit quadratic composition dependence while the helical pitch length (p=2π/q) varies linearly. Both q and P_m vanish discontinuously at the C-C* …

Magmatic Evolution And Eruptive History Of The Granitic Bumping Lake Pluton, Washington: Source Of The Bumping River And Cash Prairie Tuffs, John Frederick King

Dissertations and Theses

The 25 Ma Bumping Lake pluton ranges in composition from quartz diorite to granite with the granitic facies comprising approximately 90% of the pluton's surface area. The granite may be classified as calcalkaline, peraluminous and I-type with some Stype characteristics. A late-stage, mafic-poor facies fills cooling related extensional fractures. The pluton was passively emplaced into the Ohanapecosh Formation at a shallow level in the crust. Contact relationships vary from sharp where the contact is vertical to gradational at the roof of the pluton. Where gradational, stoped xenoliths from the roof of the pluton increase in size, angularity and retain more …

An Experimental Study Of Scotopic Sensitivity/Irlen Syndrome In Learning Disabled Students, Kathleen Hickam Farber

Dissertations and Theses

This study examined the effect on reading performance of a controversial treatment for a dysfunction of visual perception known as Scotopic sensitivity/lrlen Syndrome. The treatment, referred to as spectral modification, involved the use of colored transparent overlays for reading by four elementary school children in their actual school environments.

The diagnostic, prescriptive and remediation procedures used in this study were originally developed by Helen Irlen, a California psychologist and researcher. Irlen conceptualized Scotopic Sensitivity Syndrome as a difficulty in visual processing of the printed page when perceived through full spectrum light. Spectral modification techniques were considered controversial in that they …

Fluttering Fountains: Stability Criteria, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The fluttering oscillations that have long been seen in falling sheets of water have recently been subjected to detailed theoretical analysis. In this study stability criteria for these oscillations are derived and discussed. These criteria provide insight into the physical mechanisms of the instability and may be employed in the design of fluttering waterfall systems.

Structure And Phase Transition Of The 6,5-Annulene Isomer Of C_{61}H_{2}, Andrea N. Lommen, Paul A. Heiney, Gavin B. M. Vaughan, Peter W. Stephens, Dengfa Liu, Dayin Li, Allan L. Smith, Andrew R. Mcghie, Robert M. Strongin, Laurent Brard, Amos B. Smith Iii

Chemistry Faculty Publications and Presentations

We have used differential scanning calorimetry and x-ray diffraction to study the crystalline phases of the 6,5-annulene isomer of C₆₁H₂. At 308 K the methylenated fullerenes are orientationally disordered in a face-centered cubic lattice with lattice parameter 14.19±0.02 Å. Below Tc=290 K the symmetry is lowered to Pa3¯, a simple-cubic structure. At 20 K the lattice parameter is 14.06±0.02 Å, with substantial statistical disorder remaining. The transition temperature in C₆₁H₂ is slightly higher than in C₆₀O and higher still than in C₆₀, but the three compounds exhibit orientationally …

A User-Level Process Package For Concurrent Computing, Ravi Konuru, Steve Otto, Jonathan Walpole, Robert Prouty, Jeremy Casas

Computer Science Faculty Publications and Presentations

A lightweight user-level process(ULP) package for parallel computing is described. Each ULP has its own register context, stack, data and heap space and communication with other ULPs is performed using locally synchronous, location transparent, message passing primitives. The aim of the package is to provide support for lightweight over-decomposition, optimized local communication and transparent dynamic migration. The package supports a subset of the Parallel Virtual Machine(PVM) interface[Sun90).

Higher Education And Economic Issues In Oregon: A Current Picture, City Club Of Portland (Portland, Or.)

City Club of Portland

No abstract provided.

Logic Synthesis With High Testability For Cellular Arrays, Andisheh Sarabi

Dissertations and Theses

The new Field Programmable Gate Array (FPGA) technologies and their structures have opened up new approaches to logic design and synthesis. The main feature of an FPGA is an array of logic blocks surrounded by a programmable interconnection structure. Cellular FPGAs are a special class of FPGAs which are distinguished by their fine granularity and their emphasis on local cell interconnects. While these characteristics call for specialized synthesis tools, the availability of logic gates other than Boolean AND, OR and NOT in these architectures opens up new possibilities for synthesis. Among the possible realizations of Boolean functions, XOR logic is …

An Analysis Of The Linked-Pulse In Steady-State Free Precession In Mri, Fang Li

Dissertations and Theses

The steady-state free precession (SSFP) is one type of the fast scanning technique in MRI. So far most of its analysis are concentrated on the gradient echo SSFP (GR SSFP), very few paper discuss the spin echo SSFP (SE SSFP), and they are usually based on the simplified the hard pulse assumption. The advantage of the SE SSFP is that it can refocus the dephasing caused by the magnetic field inhomogeneity, which is the disadvantage of the GR SSFP. Also the hard pulse model can provide very limited information.

The purpose of this paper is to establish the soft pulse …

The Holocene Sedimentary Framework Of The Lower Columbia River Basin, Edward Breed Gates

Dissertations and Theses

The Columbia River is the largest fluvially dominated estuary in the Pacific Northwest, yet the Holocene transgressive fill of this system has not previously been studied. Nearly 1500 industry borehole and water well records in the lower Columbia River basin (LCRB) were analyzed. These records document the sedimentary infilling of the lower 120 miles of the drowned river valley that occurred during the Holocene marine transgression (10-0 ka). Of particular importance is a key stratigraphic marker horizon of volcanic tephra that has been identified throughout the LCRB. INAA was used to determine the geochemical composition of the target tephra layer. …

Genetic Algorithms And Artificial Life, Melanie Mitchell, Stephanie Forrest

Computer Science Faculty Publications and Presentations

Genetic algorithms are computational models of evolution that play a central role in many artificial-life models. We review the history and current scope of research on genetic algorithms in artificial life, giving illustrative examples in which the genetic algorithm is used to study how learning and evolution interact, and to model ecosystems, immune system, cognitive systems, and social systems. We also outline a number of open questions and future directions for genetic algorithms in artificial-life research

Synthesis And Characterization Of Some Flourine-Containing Lithium Alkyl Sulfonates: Flourinated Sulfonates And Sf5-Containing Sulfonates, Steven A. Ullrich

Dissertations and Theses

Lithium salts of pentafluorothio alkyl sulfonic acids and perfluoroalkyl disulfonic acids were prepared for testing for possible use as polymer electrolytes. Most of these lithium salts were made from the corresponding sodium, potassium or calcium salts. Aqueous solutions of these salts were passed through polystyrene sulfonate ion exchange resin in the acid form to obtain aqueous solutions of the corresponding acids. The acids were then neutralized with lithium hydroxide using a pH meter. One salt was made by reacting the barium salt of the corresponding acid with lithium sulfate. A sulfonyl fluoride polymer (-0-CH2-C (CH20CF2CF2S02F) H-) n was reacted with …