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Vortex Wake And Exhaust Plume Interaction, Including Ground Effect, Ihab Gaber Adam

Mechanical & Aerospace Engineering Theses & Dissertations

Computational modeling and studies of the near-field wake-vortex turbulent flows, far-field turbulent wake-vortex/exhaust-plume interaction for subsonic and High Speed Civil Transport (HSCT) airplane, and wake-vortex/exhaust-plume interaction with the ground are carried out. The three-dimensional, compressible Reynolds-Averaged Navier-Stokes (RANS) equations are solved using the implicit, upwind, Roe-flux-differencing, finite-volume scheme. The turbulence models of Baldwin and Lomax, one-equation model of Spalart and Allmaras and two-equation shear stress transport model of Menter are implemented with the RANS solver for turbulent-flow modeling.

For the near-field study, computations are carried out on a fine grid for a rectangular wing with a NACA-0012 airfoil section and …

Superconvergence In Iterated Solutions Of Integral Equations, Peter A. Padilla

Mathematics & Statistics Theses & Dissertations

In this thesis, we investigate the superconvergence phenomenon of the iterated numerical solutions for the Fredholm integral equations of the second kind as well as a class of nonliner Hammerstein equations. The term superconvergence was first described in the early 70s in connection with the solution of two-point boundary value problems and other related partial differential equations. Superconvergence in this context was understood to mean that the order of convergence of the numerical solutions arising from the Galerkin as well as the collocation method is higher at the knots than we might expect from the numerical solutions that are obtained …

The Solution Of Hypersingular Integral Equations With Applications In Acoustics And Fracture Mechanics, Richard S. St. John

Mathematics & Statistics Theses & Dissertations

The numerical solution of two classes of hypersingular integral equations is addressed. Both classes are integral equations of the first kind, and are hypersingular due to a kernel containing a Hadamard singularity. The convergence of a Galerkin method and a collocation method is discussed and computationally efficient algorithms are developed for each class of hypersingular integral equation.

Interest in these classes of hypersingular integral equations is due to their occurrence in many physical applications. In particular, investigations into the scattering of acoustic waves by moving objects and the study of dynamic Griffith crack problems has necessitated a computationally efficient technique …

Shoreline Change Modeling As A Tool In Coastal Environmental Management, Jorge Espinoza Amaguana

Civil & Environmental Engineering Theses & Dissertations

The one-line numerical model GENESIS has been calibrated to evaluate its performance as a tool in providing insights into the physical components to manage the coastal environment. To calibrate the model, physical environmental data, literature research, and computer modeling methodologies were utilized in addressing the objectives of this thesis. The model was applied at three beaches of the Virginia Beach City with different man-made structures by using the actual field wave data for wave year J 997. Waves are the main environmental component affecting the coastal system; however, additional environmental data and the best engineering decision were used as model …

Determination Of The N-Terminal Amino Acid Residues On Polypeptides In Secondary Wastewaters, Edward L. Creecy

Chemistry & Biochemistry Theses & Dissertations

The N-terminal amino acid residues on polypeptides and proteins were determined in wastewaters prior to chlorination. The terminal amino groups'ere first derivatized with the well known derivatizing agent dansyl chloride, and then the resulting dansyl amino acid hydrolyzed from the peptide chain by a propionic acid/ hydrochloric acid mixture. The resulting dansyl amino acids were then separated and detected using reversed phase high performance liquid chromatography with fluorescence detection. The majority of N-terminal residues detected were the more polar amino acids. Concentrations ranged from 1 x 10^-10 to 3 x 10^-7 moles/liter. It is suggested that the shorter …

Multiple Streams Synchronization In Collaborative Multimedia Systems, Emilia Stoica

Computer Science Theses & Dissertations

With the recent increase of the communication bandwidth and processor power, new types of applications have emerged. Among them, there are multimedia application, in which users are able to control, combine, and manipulate different types of media, such as text, sound, video, computer graphics, and animation. A key requirement in any multimedia application is to synchronize the delivery of various media streams to the user. To achieve this, the sender has to provide the temporal relations between the streams as they are captured. Since the receiver uses this information in streams presentation, its accuracy is very important.

Our main contribution …

An Essay On Uncertainty And Fact-Finding In Civil Litigation, With Special Reference To Contract Cases, Alex Stein

Faculty Scholarship

No abstract provided.

Halt Phase Strategy: New Wine In Old Skins . . . With Powerpoint, Earl H. Tilford Dr.

Books, Monographs & Collaborative Studies

Analyzes the Halt Phase Strategy/Doctrine currently advocated by the Air Force. As a part of his analysis, the author traces the immediate origins of Report of the Quadrennial Defense Review. Dr. Tilford contends, however, that Halt's real origins are more closely identified with intrinsic Air Force strategic bombing doctrine, and are to be found in strategies associated with atomic and nuclear deterrence and warfighting. Thus, he concludes that Halt is really "new wine in old skins" being presented today more aggressively because of rapid technological advances.

Optimization Of Variable Area Transect Sampling Using Monte Carlo Simulation, Richard M. Engeman, Robert T. Sugihara

United States Department of Agriculture Wildlife Services: Staff Publications

An extensive simulation study was conducted to optimize the number, r, of population members to be encountered from each random starting point in variable area transect (VAT) sampling. The quality of estimation provided by the original calculation formula presented by K. R. Parker in 1979 was compared to another formula that was a Morisita analog intended to reduce bias when sampling aggregated populations. Monte Carlo simulations covered 64 combinations of four spatial patterns, four sample sizes, and four densities. Values of r from 3 through 10 were considered in each case. Relative root mean squared error was used as …

Thermal Stability And Nanostructure Of Cocrpt Longitudinal Recording Media, Mingjun Yu, Mary F. Doerner, David J. Sellmyer

David Sellmyer Publications

We report a systematic study of activation volumes and their correlation with physical grain sizes and thermal stability in CoCrPt media fabricated by magnetron sputtering. Different underlayers and CoCrPt layer thicknesses were used to provide a range of lateral grain sizes, M_Iδ (product of remanence M_I and film thickness δ) values, and remanence coercivities. Two methods, namely the field-sweep-rate dependence of coercivity and measurements of magnetic viscosity and irreversible susceptibility, were used to determine the activation volumes and the results obtained from the two methods are in reasonable agreement. For CoCrPt layer thickness from 10 nm to …

Measurement Of The Photorefractive Grating Phase Shift In A Polymer By An Ac Phase-Modulation Technique, Martin M Liphardt, Stephen Ducharme

Stephen Ducharme Publications

The complex coupling constant of a photorefractive polymer was measured as a function of an applied electric field by use of a modified ac phase modulation technique. We determined that both a photorefractive index grating and a nonphotorefractive absorption grating were present. The electric field dependencies of the amplitude and the phase of the photorefractive gain coefficient were accurately described by standard photorefractive theory. The accuracy of the photorefractive phase shift as measured by this phase-modulation technique was ±1° near phase shifts of 90° and ±3° near phase shifts of 45°.

Structure And Lattice Dynamics Of Dipolarly Disordered 2,3-Dimethylanthracene Crystals, M. Dörr, H. Gerlach, J. Kalus, N. Karl, M. Monkenbusch, I. Natkaniec, U. Schmelzer, W. Schmidt, John J. Stezowski, P. Vorderwisch, M. Warth

John J. Stezowski Publications

2,3-dimethylanthracene (2,3-DMA, C₁₆H₁₄) crystallizes in a pseudocentrosymmetric triclinic lattice with two molecules per unit cell showing dipolar structural disorder of the acentric molecules. Using powder samples the amplitude weighted phonon density of states was measured by inelastic incoherent neutron scattering for different degrees of deuteration. The differences in the resulting spectra can be explained by changes of the dynamics of the molecular bodies or the methyl side groups. By the method of inelastic coherent neutron scattering phonon dispersion curves were determined. The phonon lines are broad even at low temperatures; this fact is supposed to be …

Iron And Nickel Surface And Interface Anisotropies, Ralph Skomski, D. Sander, C. Schmidthals, Axel Enders, J. Kirschner

Ralph Skomski Publications

The anisotropy of fcc (111) Fe/Ni and Fe/Ni/Fe layers is investigated. The films exhibit an oscillating behavior of the preferential magnetization direction depending on whether the surface layer is Ni or Fe. Anisotropy fields are obtained from polar and perpendicular Kerr hysteresis loops and yield a comparatively small perpendicular Fe/Ni interface anisotropy of about 0.15 mJ/m2. The real-space origin of the interface anisotropy is the interlayer hybridization of the yz, zx, and z² orbitals.

Chemical Synthesis Of Nanostructured Cobalt At Elevated Temperatures, Diandra Leslie-Pelecky, M. Bonder, T. Martin, E.M. Kirkpatrick, X.Q. Zhang, S.-H. Kim, Reuben D. Reike

Diandra Leslie-Pelecky Publications

Chemical synthesis is a versatile technique for fabricating novel nanostructured materials. In the Rieke process, a metal salt is reduced by an alkali in a hydrocarbon solvent to form small, highly reactive particles. Synthesis at an elevated temperature (200°C) increases the as-synthesized particle size and produces higher coercivities and remanence ratios than observed in similar syntheses at room temperature. The ratio of synthesis temperature to solvent boiling point appears to be an important parameter in both coercivity and oxidation resistance.

The Political Personality Of U.S. Vice President Al Gore, Aubrey Immelman

Psychology Faculty Publications

This paper presents the results of an indirect psychodiagnostic assessment of the political personality of U.S. vice president Al Gore, Democratic nominee in the 2000 presidential election, from the conceptual perspective of Theodore Millon.

Information concerning Al Gore was collected from published biographical and autobiographical accounts and political reports in the print media, and synthesized into personality profiles using the second edition of the Millon Inventory of Diagnostic Criteria (MIDC), which yields 34 normal and maladaptive personality classifications congruent with Axis II of DSM-IV.

The personality profile yielded by the MIDC was analyzed on the basis of interpretive guidelines …

กิจกรรมสิ่งแวดล้อม

Thai Environment

No abstract provided.

การพัฒนาพื้นที่ชายฝั่งทะเลภาคใต้ กับ แผนการจัดการสิ่งแวดล้อม, พรชัย สุตันไชยนนท์

Thai Environment

No abstract provided.

Probing Electronic Radial Wave Packets Using Impulsive Momentum Retrieval, M. B. Campbell, Thomas J. Bensky, Robert R. Jones

Physics

Subpicosecond half-cycle pulses and a single-shot imaging detector have been used to monitor the evolution of electronic radial wave packets in calcium. The time-dependent momentum-space probability distribution is obtained using the impulsive momentum retrieval (IMR) method. The measured distributions are compared to the results of quantum and classical simulations allowing a comprehensive evaluation of the benefits and limitations of the IMR method.

Quantum Theory Of The Linewidth Of A Laser With A Saturable Absorber: Phase Diffusion, Michael Sokol

Electrical Engineering and Computer Science Faculty Publications

A quantum theory of the spectral width of a laser with a saturable absorber is presented. We perform a density matrix calculation yielding the off-diagonal element ρ n,n+1(t) which is proportional to the average value of the electric field associated with the laser field having a large photon number n. The general linewidth theory is applied to any general laser which has saturable absorber features for a portion of the building of the laser field. We have found that the saturable absorber action contribution to the linewidth of such a laser can be substantial. © 1998 Society of Photo-Optical Instrumentation …

Review Of The United States And Arms Control: The Challenge Of Leadership By Allan S. Krass, David W. Hafemeister

Physics

No abstract provided.

1998 July, Office Of Communications & Marketing, Morehead State University.

Morehead State Press Release Archive, 1961 to the Present

Morehead State University press releases for July of 1998.

Digital Image Retrieval Using Shape-Based Queries, James Carswell

Conference papers

In this paper we present the development of a spatial data management system utilizing sketch-based queries for the content-based retrieval of digital images from topographic databases. We discuss our overall strategy and associated algorithmic and implementational aspects, and present the associated database design issues. The query tools devised in this research are employing user-provided sketches of the shape and spatial configuration of the object(s) which should appear in the images to be retrieved. Our strategy is scale-independent. It is inspired by least-squares matching (lsm), and represents an extension of lsm to function with a variety of raster representations. The results …

Nonlinear Field Dependence Of The Mobility Of A Charge Subjected To A Superposition Of Dichotomous Stochastic Potentials, A. M. Kenkre, Marek Kus, David H. Dunlap, Paul Ernest Parris

Physics Faculty Research & Creative Works

A general prescription is presented to address a large variety of forms of the nonlinear dependence of the static charge mobility on the applied electric field. The system consists of a classical charge subjected to an arbitrarily strong steady state electric field and to a stochastic potential consisting of a linear superposition of an unlimited number of dichotomous potentials in one-dimensional space. It is shown that the nonlinear mobility can be calculated for arbitrary forms of the density function of the individual dichotomous components of the stochastic potential. Specific cases of physical interest are analyzed. One of them provides a …

High Pressure Radio-Frequency Microhollow Cathode Discharges, Anja Annett Muller

Electrical & Computer Engineering Theses & Dissertations

A new field of microhollow cathode discharges is represented by the RF microhollow cathode discharge. So far, the behavior and related physical processes of the RF microhollow cathode discharge are not well investigated.

RF microhollow discharges in air at high pressures were investigated under different experimental conditions. The geometry was changed by reducing the cathode hole diameter and the dielectric spacer thickness. By adding a noble gas to air, the influence of additive gases was explored. Additionally, the parallel operation of RF microhollow discharges was investigated.

It was shown that stable RF microhollow cathode discharges could only be sustained up …

Nonlinear Stability And Control Of Three-Dimensional Boundary Layers, Erik Janke

Mechanical & Aerospace Engineering Theses & Dissertations

The linear and nonlinear evolution of steady and traveling disturbances in three-dimensional incompressible boundary layer flows is studied using Parabolized Stability Equations (PSE). Extensive primary stability analyses for the model problems of Swept Hiemenz flow and the DLR Transition experiment on a swept flat plate are performed first. Second, and building upon these results, detailed secondary instability studies based on both the classical Floquet Theory and a novel approach that uses the nonlinear PSE are conducted. The investigations reveal a connection of unstable secondary eigenvalues to both the linear eigenvalue spectrum of the undisturbed mean flow and the continuous spectrum, …

A Method For The Measurement Of Divalent Cations In Solutions Of Carboxymethylcellulose, J. Todd Henderson

Theses

The purpose of this research was to develop a method that would quantify the divalent cations in aqueous solutions of sodium carboxymethylcellulose. The technique employed for the elemental analysis was Inductively Coupled Plasma Emission Spectroscopy (ICP). It was found using multiple filtrations, through filters of different pore sizes, that the polymer could be removed from solution thus allowing the remaining cation concentration to be determined. The data obtained suggest that ICP ES allows precise determination of Magnesium, Calcium, or Strontium concentrations for CMC solutions of varying ionic strengths. The method was then used to look for trends between the percent …

The Role Of Soil Test Information In Reducing Groundwater Pollution, Ronald A. Fleming, Richard M. Adams, David E. Ervin

Economics Faculty Publications and Presentations

Testing soils for nutrients is expected to improve groundwater quality. However, it is unknown whether soil testing will improve groundwater quality sufficiently to decrease the demand for direct regulation of agricultural practices. Focusing on an irrigated agricultural region in eastern Oregon, the economic and environmental aspects of soil testing are assessed using a spatially distributed, dynamic simulation model which links economic behavior with the physical processes that determine groundwater quality. Results indicate that soil testing of all fields increases farm profits and reduces groundwater nitrate concentration. However, the benefits are small in terms of potential improvements in groundwater quality.

The Judging Process For Sym Bowl: A High School System Dynamics Modeling Competition, Wayne W. Wakeland

Complex Systems Faculty Publications and Presentations

This “paper” describes the judging process used to determine the winners in SymBowl, a high school system dynamics modeling competition held in Portland, Oregon the past three years. SymBowl was created by Ed Gallaher, a medical researcher at the Portland VA Hospital and Associate Professor at Oregon Health Sciences University.

The judging criteria and judging process were developed by Wakeland, who has served as the judging coordinating for past three years, overseeing the process, compiling results, etc. Wakeland is an Adjunct Professor of System Science at Portland State University where he teaches graduate-level modeling and simulation classes.

Armstrong Academics Summer/Fall 1998, Armstrong Atlantic State University

Armstrong State University Collections: Armstrong Academics (Archived)

No abstract provided.

Approximate Analytical Relationships For Linear Optimal Aeroelastic Flight Control Laws, Ayman Hamdy Kassem

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation introduces new methods to uncover functional relationships between design parameters of a contemporary control design technique and the resulting closed-loop properties. Three new methods are developed for generating such relationships through analytical expressions: the Direct Eigen-Based Technique, the Order of Magnitude Technique, and the Cost Function Imbedding Technique. Efforts concentrated on the linear-quadratic state-feedback control-design technique applied to an aeroelastic flight control task. For this specific application, simple and accurate analytical expressions for the closed-loop eigenvalues and zeros in terms of basic parameters such as stability and control derivatives, structural vibration damping and natural frequency, and cost function …