Digital Commons Network^™

Energetic Protons And Deuterons Emitted Following Μ⁻ Capture By ³He Nuclei, W. J. Cummings, G. E. Dodge, S. S. Hanna, B. H. King, S. E. Kuhn, Y. M. Shin, R. Helmer, R. B. Schubank, N. R. Stevenson, U. Wienands, Y. K. Lee, G. R. Mason, B. E. King, K. S. Chung, J. M. Lee, D. P. Rosenzweig

Physics Faculty Publications

Spectra of energetic protons and deuterons emitted following negative muon capture from rest in ³He have been measured for the first time. Significant capture strength is observed at high energy transfers (mμ- E_v >60 MeV) for the two-body and three-body breakup channels, indicative of the importance of nucleon-nucleon correlations and meson exchange currents in the capture process. A simple plane wave impulse approximation calculation reproduces the proton spectrum reasonably well, but underpredicts the deuteron rate at the highest energies by a large factor.

A Paleoenvironmental Analysis Based On Ostracode Assemblages From The Late Pliocene Tuapaktushak And Middle Pleistocene Karmuk Members Of The Gubik Formation Of The Arctic Coastal Plain, Western Alaska, D. E. Loehrke

OES Theses and Dissertations

This study records and analyzes ostracode assemblages recovered from sediments assigned to the Late Pliocene Tuapaktushak and Middle Pleistocene Karmuk members of the Gubik Formation in the Skull Cliff area of the Arctic Coastal Plain in western Alaska. Forty-three species were identified from 47 samples (25 from the Tuapaktushak Member and 23 from the Karmuk Member). Samples were grouped by Q-mode cluster analysis and by member assignment for the purpose of analysis.

Paleoenvironmental analyses of ostracode assemblages representative of each cluster suggest all samples, regardless of cluster membership, were deposited in similar marine environments where water depths were in the …

Bounds On Constraint Weight Parameters Of Hopfield Networks For Stability Of Optimization Problem Solutions, Gursel Serpen

Electrical & Computer Engineering Theses & Dissertations

The purpose of the presented research is to study the convergence characteristics of Hopfield network dynamics. The relation between constraint weight parameter values and the stability of solutions of constraint satisfaction and optimization problems mapped to Hopfield networks is investigated. A theoretical development relating constraint weight parameter values to solution stability is presented. The dependency of solution stability on constraint weight parameter values is shown employing an abstract optimization problem. A theorem defining bounds on the constraint weight parameter magnitudes for solution stability of constraint satisfaction and optimization problems is proved. Simulation analysis on a set of optimization and constraint …

Temperature And Suction Effects On The Instability Of An Infinite Swept Attachment Line, D. G. Lasseigne, T. L. Jackson, F. Q. Hu

Mathematics & Statistics Faculty Publications

It is known that the incompressible, infinite swept attachment line flow is unstable to streamwise disturbances that originate in the boundary layer when the cross-flow exceeds a critical magnitude. Furthermore, a small degree of suction at the surface has a significant stabilizing influence while a small degree of blowing has a considerable destabilizing influence. This paper investigates the stabilizing and destabilizing effects of, respectively, cooling or heating the plate and the competing or enhancing effects of suction or blowing. A nonorthogonal flow with respect to the attachment line is also considered by adding a component of shear to the mean …

Numerical Solutions For Weakly Singular Hammerstein Equations And Their Superconvergence, Hideaki Kaneko, Richard D. Noren, Yuesheng Xu

Mathematics & Statistics Faculty Publications

In the recent paper [7], it was shown that the solutions of weakly singular Hammerstein equations satisfy certain regularity properties. Using this result, the optimal convergence rate of a standard piecewise polynomial collocation method and that of the recently proposed collocationtype method of Kumar and Sloan [10] are obtained. Superconvergence of both of these methods are also presented. In the final section, we discuss briefly a standard productintegration method for weakly singular Hammerstein equations and indicate its superconvergence property. © 1992 Rocky Mountain Mathematics Consortium.

Solution Uniqueness And Stability Criteria For A Model Of Growth Factor Production, J. A. Adam

Mathematics & Statistics Faculty Publications

Uniqueness and stability criteria are established for the steady states of a nonlinear model of growth factor production. A specific expression for the nonlinearity is chosen, containing three parameters which can be adjusted to fit a specific biological context, but much of the analysis applies to a general class of source terms that exhibit the same qualitative behavior.

Nurse Manager Role Stress, Rosemarie Mohn

Ellmer School of Nursing Theses & Dissertations

The purpose of this study was to examine the influence of decision-making style, and right and left brain function on nurse manager role stress. Data were collected from 48 nurse managers employed at four acute care facilities along the Atlantic seaboard. A nonexperimental correlation descriptive design was utilized to determine if any positive or negative correlation existed between study variables and levels of stress. Findings suggested that nurse managers experienced moderate amounts of role stress, including role conflict and role ambiguity. One significant statistical correlation existed between role ambiguity and the decision making dimension of intuition. Recommendations for future research …

A Case Study In Software Reuse: The Rntds Architecture, Barry J. Stevens

Computer Science Theses & Dissertations

It has been asserted that the most significant gains in software productivity will come from increased levels of software reuse. Some economic models for predicting savings through software reuse exist, but none are based on actual project experience. This paper surveys those models and presents the results of a case study, the Restructured Naval Tactical Data Systems (RNTDS) architecture, in the light of those models. According to the models, software reuse via the RNTDS architecture has enabled the production of fourteen major computer programs at five to twenty-one percent of the cost to create them without software reuse. Organizational characteristics …

Study Of The Heavy Fermion/Spin-Glass System, Ce1-X GdX Al3, Using 155Gd Mossbauer Spectroscopy, Nicholas G. Ruggiero

Physics Theses & Dissertations

The magnetic properties of Ce_1-xGd_x.Al₃ have been studied using ¹⁵⁵Gd Mossbauer spectroscopy. It has been shown that the magnetic moments of the host GdAl₃ are constrained to the basal plane. The magnetic properties of GdAl₃ can best be described in the framework of RKKY theory. Prior studies of Ce_1-xGd_xAl₃, have revealed complex magnetic behavior throughout the series. As observed with Mossbauer spectroscopy magnetic ordering occurs for x ≥ 0.5, though not at the reported spin glass temperatures. For x = 0.23 and x = 0.18, the …

Vorticity Dynamics Of Seasonal Variations Of The Antarctic Circumpolar Current From A Modeling Study, John M. Klinck

CCPO Publications

A one-layer numerical model was developed to analyze the vorticity dynamics of the seasonal variations of currents in the Southern Ocean. The model includes the continental geometry and bathymetry of the Southern Ocean and is forced by monthly climatological wind stress. Five cases are considered that compare (i) circulation over a flat bottom to that with bathymetry, (ii) effects of zonally averaged wind stress forcing versus the climatological forcing and (iii) anomaly wind stress (winds with the annual mean removed) versus the full stress. The individual terms in the vorticity conservation equation are calculated from the model solution along two …

Approaches To High Speed Networks, Frank Charles Paterra

Computer Science Theses & Dissertations

This work investigates possible methods by which existing potentially available communication bandwidth can be used by communication intensive applications. Presently fiber optic media are available that can provide multiple gigabits of throughput. Unfortunately, because of the computation overhead required to insure that data are reliably transmitted this capacity has not been tapped.

A survey of work toward enabling the use of the potential bandwidth is presented. The parallel paradigm is identified as a strong candidate for providing significant increases in system usable bandwidth. Performing communication processing in parallel, however, presents the developer with several implementation options. These options are considered …

Finite Element Frequency Domain Solution Of Nonlinear Panel Flutter With Temperature Effects And Fatigue Life Analysis, David Yongxiang Xue

Mechanical & Aerospace Engineering Theses & Dissertations

A frequency domain solution method for nonlinear panel flutter with thermal effects using a consistent finite element formulation has been developed. The von Karman nonlinear strain-displacement relation is used to account for large deflections, the quasi-steady first-order piston theory is employed for aerodynamic loading and the quasi-steady thermal stress theory is applied for the thermal stresses with a given change of the temperature distribution, ΔΤ (x, y, z). The equation of motion under a combined thermal-aerodynamic loading can be mathematically separated into two equations and then solved in sequence: (1) thermal-aerodynamic postbuckling and (2) limit-cycle oscillation. The Newton-Raphson iteration technique …

Processes Affecting The Behavior Of Redox-Sensitive Elements In Chesapeake Bay, Maria Lourdes San Diego-Mcglone

OES Theses and Dissertations

Several processes can affect variations in the chemical composition of an estuary, including (1) biogeochemical reactions in the water column, (2) advective transport, and (3) diffusion from underlying sediments.

The purpose of the study was to establish whether estuarine redox reactions are controlled by a complex interaction of processes 1 to 3. Short-term and long-term studies were conducted in Chesapeake Bay. Redox species involved in redox cycling include oxygen, iron, manganese, hydrogen sulfide, nitrogen species, arsenic and antimony species, while phosphate is indirectly involved in redox cycles. Silicate was used as a non-redox tracer.

For the short-term study, a Lagrangian …

Domain Limitations And Interface Requirements For Expert Developed Knowledge Based Systems, Bernard Lee Lewis

Engineering Management & Systems Engineering Theses & Dissertations

The expanded use of graphical, case-based and object oriented techniques in expert systems creation has made it more practical for domain experts to develop their own applications. This thesis focuses on the elements necessary in an expert/developer interface and looks at various forms and techniques that exemplify such an approach. The spreadsheet metaphor is used for an interface or managed set of interfaces that a domain expert can use in building his own expert system or prototype. criteria are established for such interfaces and recent commercial offerings that make expert-created knowledge-bases more practical are reviewed for techniques that qualify. Approaches …

Faculty Standardization Of Dental Hygiene Instrumentation Skill Evaluation: A Calibration Exercise, Diane-Marie Smela

Dental Hygiene Theses & Dissertations

Faculty must be standardized so that student skills are assessed in an unbiased, equal fashion. The purpose of this study was to determine the impact of calibration on dental hygiene faculty standardization. Examples of correct and incorrect instrumentation skill performance were demonstrated and discussed during the calibration exercise. Groups simultaneously viewed instrumentation skills while assessing correct or incorrect performance. Group standardization was determined through analysis of answer key agreement, intra-rater reliability, and inter-rater reliability. Data were statistically analyzed through the use of a z-test for both answer key agreement and inter-rater reliability, and chi-square (x²) for inter-rater reliability …

Thermal Characterization Of Carbon Monoxide Oxidation Catalysts Using Thermogravimetric Analysts And Differential Scanning Calorimetry, Rene A. Bartgis

Chemistry & Biochemistry Theses & Dissertations

Catalysts composed of platinum and/or palladium on tin (IV) oxide supports, with and without silica gel, as well as catalysts composed of gold on manganese oxide, have been developed for the recombination of carbon monoxide and oxygen to form carbon dioxide for use in carbon dioxide lasers. A thermogravimetric method and a differential scanning calorimetric method have been developed for the thermal characterization of these catalysts. The mass loss data and the enthalpy changes determined as the catalysts lost water were then related to existing activity data for these catalysts. No relationship was found between the thermal data and the …

The Geomorphology Of Alluvial Fan Deposits On The West Flank Of The Blue Ridge, Augusta County, Virginia, Debra Lynn Duffy

OES Theses and Dissertations

Large coalescing alluvial fans mantle the carbonate and shale formations west of the Blue Ridge mountains near Stuarts Draft, Virginia. Fan sediments are predominantly boulder and cobble gravels derived from the Antietam Quartzite, The fan complex consists of three alluvial units of significantly different ages. The surface of each fan unit was mapped using relative geomorphic position, soil color, clay content and thickness of Bt horizons, clast weathering, and degree of removal of depositional surfaces by stream incision. A five-category quartzite clast weathering scale developed for this study was very effective as a measure to distinguish map units. Stratigraphic data …

Linearized Dynamics Of Space Structures With Articulated Appendages, Gopichand Koganti

Mechanical & Aerospace Engineering Theses & Dissertations

The inherent difficulties of the conventional spacecraft design, which first considered the optimization with respect to structural variables and then with respect to control variables, have led to the concept of Controls-Structures Interactive Design. The success of the CSI design of Space structures without articulated appendages has prompted the extension of the CSI design to systems with articulated appendages. The presentation is of two parts, the first part deals with the derivations of the equations of motion and the second part deals with the eigenvalue/vector approximations.

Three approaches, namely: the multibody approach, the finite element based approach with hinge joints …

The Identification, Distribution, And Status Of The Threatened Dismal Swamp Shrew (Sorex Longirostris Fisheri), Thomas M. Padgett

Biological Sciences Theses & Dissertations

Southeastern shrews (Sorex longirostris) were trapped throughout southeastern Virginia and northeastern North Carolina to determine if any morphological characters could

be identified that would aid in the identification and distribution of the threatened subspecies Sorex l._ fisheri, endemic to the Great Dismal Swamp, the more upland nominate subspecies Sorex l. longirostris, and possible intergrades between the two subspecies. Animals were classified a priori into three groups, based on their location of capture. Animals collected from the Great Dismal Swamp National Wildlife Refuge (GDSNWR) and associated bottomland habitats were designated as "fisheri", animals collected farthest from the Swamp as "longirostris", and …

Multiple Cue Probability Learning: Effects Of Individual Differences On Mcpl Performance, Catherine Q. Greenwald

Psychology Theses & Dissertations

This exploratory study investigated individual difference effects on multiple cue probability learning performance. Measures of cognitive complexity, creativity, problem solving ability, and anxiety were correlated with the NCPL indices of performance. Eighty participants (40 men and 40 women) were randomly selected graduate students from the six colleges of Old Dominion University. Results showed significant Pearson Product Moment correlations among the Level 2 NCPL achievement and matching indices and the predictors Career Path Appreciation phrase card average, Kirton Adaptation Innovation Inventory, Quantitative GRE scores, gender, and anxiety. There is some evidence that MCPL performance can be explained in terms of these …

Reactions Of Aqueous Chlorine With Valine In Model Solutions And In Wastewater, Erika Forrer Mccormick

Chemistry & Biochemistry Theses & Dissertations

Solutions of the amino acid valine were chlorinated to seven chlorine-to-nitrogen mole (Cl/N) ratios and analyzed by high performance liquid chromatography, gas chromatography/mass spectroscopy, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The chlorination products found were N-chlorovaline, isobutyraldehyde, isobutyronitrile, and N-chloroisobutyraldimine. Their product distribution depends on the level of chlorination and pH. The main products identified at the lower CI/N mole ratios were N-chlorovaline and isobutyraldehyde, whereas at the higher CI/N mole ratios isobutyronitrile and N-chloroisobutyraldimine were identified as the main products. The concentration and the chlorination products of valine in municipal wastewater were also determined. The chlorination products of …

Community Structure Of The Macrobenthos In Back Bay, Virginia, Michael F. Lane

Biological Sciences Theses & Dissertations

A study of the subtidal macrobenthos in Back Bay, Virginia was conducted to examine community structure in relation to sedimentary and water quality characteristics. Samples were collected in August and November of 1987 and February and May of 1988 at ten stations.

Three site groups and three temporal groups were identified by cluster analyses of species abundance. Species composition between site groups was relatively homogeneous and eight species accounted for most of the variation between site groups. A comparison of plots of the biological and physical data in discriminant space suggested that variations in the biological data between site groups …

Computer Simulation Techniques To Assess Bias And Precision In The Roving Creel Survey Estimator, David L. Wade

Biological Sciences Theses & Dissertations

Fisheries scientists use roving creel survey methods to estimate total catch and total effort of recreational fisheries. Bias in the roving creel estimators had been known to the scientific community, but it had not been quantified. I developed a roving-creel-survey computer simulation model to investigate the bias and precision of roving creel estimators, and estimated parameters for the model based on field observations from the blue crab (Callinectes sapidus) fishery of the Chesapeake Bay. The computer model was used to identify bias in roving-creel effort and catch estimators and to demonstrate survey methods that will reduce this bias. …

Study Of Cathodoluminescence In Semiconductors, Mandakini V. Kale

Electrical & Computer Engineering Theses & Dissertations

Cathodoluminescence in Zn doped GaAs and ZnSe, the materials of interest for electron-beam controlled semiconductor switches, has been investigated. A new diagnostic technique, using telescopic setup of lenses, was developed to study the spatially resolved cathodoluminescence. The setup eliminated the light, other than rays from the sample, parallel to the optical axis, resulting in an enhanced spatial resolution. At high e-beam energies, light was detected, from the Zn layer region in the GaAs. It is proposed to be due to the radiative recombination of electron-hole pairs, created by the e-beam. For the polycrystalline ZnSe no light emission was detected. This …

Lava-Seawater Interactions At Shallow-Water Submarine Lava Flows, Francis J. Sansone, Joseph A. Resing, Gordon W. Tribble, Peter N. Sedwick, Kevin M. Kelly, Ken Hon

OES Faculty Publications

Hydrothermal plumes associated with nearshore lava flows from Kilauea Volcano, Hawaii were studied on five occasions during 1989-1990 to address the current lack of data on direct lava-seawater interactions. The following enrichments were found in the sea-surface hydrothermal plumes above the active underwater lava flows: H₂, 15,000x ambient seawater concentrations; Mn, 250x; and Si, 20x. Water temperatures reached 46°C. Lower concentrations and temperatures were observed in the plumes with increasing distance from shore, with H₂, Si, and Mn concentrations linearly related to seawater temperature. Unlike deep sea spreading center hydrothermal plumes, no CH₄ enrichment was …

Integrated System Identification And Adaptive State Estimation For Control Of Flexible Space Structures, Chung-Wen Chen

Mechanical & Aerospace Engineering Theses & Dissertations

Accurate state information is crucial for control of flexible space structures in which the state feedback strategy is used. The performance of a state estimator relies on accurate knowledge about both the system and its disturbances, which are represented by system model and noise covariances respectively. For flexible space structures, due to their great flexibility, obtaining good models from ground testing is not possible. In addition, the characteristics of the systems in operation may vary due to temperature gradient, reorientation, and deterioration of material, etc. Moreover, the disturbances during operation are usually not known. Therefore, adaptive methods for system identification …

A Robust Approach To Human-Computer Interface Design Using The Taguchi Method, Billie Mitchell Reed

Engineering Management & Systems Engineering Theses & Dissertations

The application of Dr. Genichi Taguchi's approach for design optimization, called Robust Design, to the design of human-computer interface software is investigated. The Taguchi Method is used to select a near optimum set of interface design alternatives to improve user acceptance of the resulting interface software product with minimum sensitivity to uncontrollable noise caused by human behavioral characteristics.

Design alternatives for interaction with personal micro-computers are identified. Several important and representative alternatives are chosen as design parameters for the Taguchi matrix experiment. A noise field with three human behavioral characteristics as noise factors were chosen as a representative noise array. …

Fast Parallel Algorithms For Basic Problems, Zhaofang Wen

Computer Science Theses & Dissertations

Parallel processing is one of the most active research areas these days. We are interested in one aspect of parallel processing, i.e. the design and analysis of parallel algorithms. Here, we focus on non-numerical parallel algorithms for basic combinatorial problems, such as data structures, selection, searching, merging and sorting. The purposes of studying these types of problems are to obtain basic building blocks which will be useful in solving complex problems, and to develop fundamental algorithmic techniques.

In this thesis, we study the following problems: priority queues, multiple search and multiple selection, and reconstruction of a binary tree from its …

Parallel-Vector Design Sensitivity Analysis In Structural Dynamics, Yongxing Zhang

Civil & Environmental Engineering Theses & Dissertations

In this study, the design sensitivity analysis is for the purpose of providing constraint derivative information for structural optimization under dynamic loads. Various existing formulations are reviewed, and the direct differentiation method is justified as the best one for design sensitivity analysis in structural dynamics. An alternative formulation for design sensitivity analysis with direct differentiation method is developed. The alternative formulation works efficiently with the reduced system of dynamic equations, and it eliminates the need for expensive and complicated eigenvector derivatives, which is required in the existing reduced system formulation. The relationship of the alternative formulation and the existing reduced …

A Diffuse Reflectance Infrared Fourier Transform Spectroscopic Study Of Platinum/Tin (Iv) Oxide Low-Temperature Carbon Monoxide Oxidation Catalysts, Donna Sue Duarte

Chemistry & Biochemistry Theses & Dissertations

Platinum-coated tin(IV) oxide catalysts have been developed for the recombination of carbon monoxide and oxygen at 55°C and 1 atmosphere of pressure in closed-cycle carbon dioxide lasers. A diffuse reflectance infrared fourier transform spectroscopic (DRIFTS) study of four of these catalysts during 5% carbon monoxide pretreatment at temperatures of 30°C, 100°c, 125°c, and 150°C has been performed. Evidence for the development of surface carbonate, bicarbonate, and formate species during pretreatment has been found. Dehydroxylation of the surface and loss of a partially charged hydrogen-bonded hydroxyl species have also been found to result from elevated temperature pretreatment. The four catalysts have …