Engineering Commons^™

Probable Maximum Flood Estimation In Northern Utah, Khin Maung Win

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The probable maximum flood (PMF) is used for the xxi assessment of maximum flood potentials in spillway sizing of new dams and in evaluating the adequacy of existing hydrologic structures. Determination of the PMF begins with the estimation of the probable maximum precipitation (PMP) for a particular dam site. Selecting hydrologic methods and assumptions for converting PMP to PMF, which are most appropriate for Utah conditions, is important to meet current inflow design flood (IDF) safety standards.

The objectives of this study were (a) to demonstrate a maximization approach to PMF determination, (b) to evaluate effects of basin characteristics and …

A Mechanistic Approach To Modeling Habitat Needs Of Drift-Feeding Salmonids, R. Craig Addley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A mechanistic model is developed to determine the habitat needs of drift-feeding stream salmonids from the direct cause-and-effect relationships of environmental and physiological variables on net energy intake (NEI). The model determines NEI by subtracting energy costs (basal metabolism, swimming cost, digestion cost) and losses (egestion and excretion) from the gross energy intake obtained as a result of simulated prey capture. The prey capture portion of the model utilizes components of the predation model of C.S. Holling and the prey capture model of N.F. Hughes and L.M. Dill to determine the rate of prey capture (gross energy intake) as a …

Analysis Of Cutthroat Flume Discharge Ratings, Liyan Ren

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sixteeen sets of original laboratory data collected by many investigators for various Cutthroat flume sizes are thoroughly reviewed and organized. Best-fit discharge parameters are obtained by performing the free-flow analysis and the submerged-flow analysis. Then, the transition submergence can be calculated. Afterwards, the unified free-flow and submerged-flow discharge parameters are developed for each flume size in order to generalize the calibrations for Cutthroat flumes. This is a very tedious process requiring a trial-and-error approach. Finally, comparisons are made of the measured laboratory discharges with the predicted discharges for both free flow and submerged flow using both the best-fit and the …

Jet Velocity Dissipation And Modelling With Aeration, Stephen J. Schlenker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of natural aeration and fall height upon velocity dissipation and modelling were studied. Underwater velocities and void ratios (proportion of air volume to total volume) were measured along the jet centerline at various depths in the receiving pool under 1- and 2-inch diameter vertical circular free-falling jets. Maximum air bubble penetration depths were also measured. In the tests, the nozzle velocities were designed so that the two differently sized models would have equivalent Froude numbers for direct comparison of respective underwater parameters. Air entrainment-the natural development of air bubbles within a pool receiving a free-falling jet-causes voids to …

Climatic Variability And Dynamics Of Great Salt Lake Hydrology, Taiye B. Sangoyomi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The time evolution of the Great Salt Lake hydro-climatic system is studied from the perspective of nonlinear dynamics. The dynamics are reconstructed in phase space using the Great Salt Lake volume time series. Important attributes for describing the system are then obtained from the reconstructed space. These include the minimum number of state variables required to describe the system inferred from a determination of the intrinsic dimension, and characterization of the system in terms of linear/nonlinear, and deterministic/stochastic. Other attributes obtained are the dominant modes of behavior of the system, as well as the limit of predictability or information loss, …

Diffraction Based Latent Image Analysis For Improving Cd Control During Lithography, Lisa-Michelle Milner

Electrical and Computer Engineering ETDs

The smallest device geometries, the critical dimensions (CDs), diminish with each generation of microelectronics. This puts more demands on the lithography process to repeatably produce these small dimensions within their 10% tolerance. I believe that individual optimization of the lithography steps will be necessary to meet the stringent demands of smaller CDs. This is possible through analysis of the latent image (the exposed, undeveloped pattern in the resist). In this work, a metrology technique is discussed for the determination of optimum lithography parameters through an interrogation of the latent image. This technique involves illuminating a latent image grating with a …

One-Dimensional Computer Modeling Of Thermal And Water Quality Characteristics Of Coldwater Lake, Wa, David Kevin Whitaker

Dissertations and Theses

Coldwater Lake is a new lake formed when a massive mudflow down the Toutle River Valley, caused by the eruption of Mount St. Helens on May 18, 1980, blocked the natural outlet of Coldwater Creek. This research utilizes physical, biological and chemical data collected at Coldwater Lake during the sun1mers of 1989 and 1990 to calibrate and verify the one-dimensional computer models CE-THERMRl and CE-QUAL-Rl for Coldwater Lake. CE-THERM-R1 was used to simulate thermal characteristics in Coldwater Lake during the summer stratification periods of 1989 and 1990. The model was calibrated to 1989 data and was verified with 1990 data. …

A Robust High Precision Algorithm For Sinewave Parameter Estimation, Kendall Ann Rydell

Dissertations and Theses

The estimation of sinewave parameters has many practical applications in test and data processing systems. Measuring the effective bits of an analog-to-digital converter and linear circuit identification are some typical examples. If a sinew ave's frequency is known, there is an established linear method to estimate the other parameters. But when none of the parameters are known (which is usually the case in practical situations), the estimation problem becomes more difficult. Traditional approaches to this task applied an iterative, sinewave curve-fit algorithm. Two problems with this technique are that convergence is often slow and not always guaranteed and the results …

The Effects Of Airline Deregulation On Airline Safety: An Econometric Analysis, William Charles De Jager

Dissertations and Theses

After an unfortunate series of accidents in the mid 1930's the Air Transport Association (ATA) lobbied Congress for regulation of the industry. The ATA claimed that unfair competition was endangering the public safety. The Civil Aeronautics Act of 1938 created the Civil Aeronautics Board (CAB) and gave the CAB the authority to regulate the industry.

During the regulation era airline ridership increased and safety improved. During the regulation period, opportunity for comparing the safety record of the regulated industry with the record of the unregulated portions of the industry was limited. The few attempts made rendered inconclusive results.

During a …

Wobbling Gear Drivetrain For Cordless Screwdriver, David K. Kedrowski, Scott P. Slimak

Honors Theses

Manufacturers of cordless screwdrivers use two planetary gear trains in series to reduce speed and multiply torque from a small electric motor. Alternately, a nutating gear drivetrain has the potential to create comparable speed reductions and torque multiplications. To apply nutating gear theory to a cordless screwdriver drivetrain, a study of spur gears, planetary gear reducers, bevel gears, and the theory of nutation was undertaken. Finally, a nutating design was proposed. The advantages of a nutating gear drivetrain over a conventional planetary gear train include: a decreased number of drivetrain parts, an ability to use lower-strength gear materials, a higher …

Low Reynolds Number Laminar Separation Bubble Control Using A Backward Facing Step, Dominique Rothan

Master's Theses - Daytona Beach

The problem of a laminar separation bubble on the upper surface of a 9.5% thick airfoil operated at low Reynolds number (R_N = 380,000) was investigated experimentally.

An unmodified LRN-010 airfoil and a modified LRN-010 airfoil with a backward facing step on its upper surface were built and tested in the ERAU wind tunnel in order to obtain pressure distributions and drag for different angles of attack.

Results were found to be in good agreement with the results obtained from the XFOIL CFD code. It was concluded that the step cutout modification improves the airfoil’s lift-to-drag ratio at low …

Simulation Model For Predicting The Impact Of Progressive Diseases In The U.S. Population By Tracking, Biju Suseelan

Masters Theses

Computer Aided Simulation is the process of designing a mathematical-logical model of a real system and experimenting with this model on a computer. Simulation encompasses a model building process as well as the design and implementation of an appropriate experiment involving that model. A simulation experiment involves observing the dynamic behavior of a model by moving from state to state in accordance with well-defined operating rules designed into the model. This research contains the development of a novel approach for the HIV transmission dynamics by using computer simulation to track the HIV positive individuals in a population and to determine …

Middle Terminal Cell Models For Efficient Over-The-Cell Routing, Siddharth Bhingarde

Masters Theses

In this thesis, we introduce a new class of cell models called Middle Terminal Models (MTM) which combines the advantages of existing cell models: BTM and CTM. This class contains the models 2MTM, 3MTM-V, and 3MTM+V depending on the number of metal layers and the permissibility of vias in over-the-cell areas. In MTM, two rows of terminals are located in the middle of the cell. This partitions over-the-cell area into three regions and allows allocation of more nets to over-the-cell area in congested channels. We prove that when vias are allowed over-the-cell, in "almost all" cases the MTM based layouts …

Silicon Carbide/Electroless Nickel Composite Plating For Aluminum Substrates, Ben Charbit

Masters Theses

The effectiveness of producing a composite coating by suspending micron-sized particles in an electroless nickel bath while plating a 2024T4 aluminum alloy part was studied. The variation in the count of particles trapped in the nickel coating due to changes in the particle size, concentration of the particles in the bath, and the substrate surface texture was also studied. Particle sizes of 1 micron and 10 microns, concentrations of 15 gr/lt and 30 gr/lt, and polished and blasted textures were used. It was found that this technique is an effective way to produce composite coatings rendering a high number of …

A Sociotechnical Approach To The Study Of Semiautonomous Work Group Communication In Technical Organizations, Elizabeth B. Varnes

Engineering Management & Systems Engineering Theses & Dissertations

The sociotechnical aspects of group communication in semiautonomous technical work teams were investigated to understand how team members define "effective" group communication and what impact technical tools have on the group communication process. A team of workers with various technical backgrounds was selected for study. The study involved videotaped group sessions, a group training educational briefing and individual group member questionnaires. The results indicate that group members believed sharing information among group members was critical to successful communication and that certain technical tools could be effective during group meetings. The findings are congruent with the general theory that group communication …

A Study Of The Interface Between A Turbulent Boundary Layer And The Irrotational Free Stream, Shih-Chao Lin

Mechanical & Aerospace Engineering Theses & Dissertations

A mathematical model has been developed to simulate the events which occur at the interface between a turbulent boundary layer and the irrotational free stream. By assuming the streamwise velocity component of this interface to be constant and that the interface is uncontorted initially, the solution to the equations of motion is used to derive the position functions of a point element on the interface. This analysis is restricted to a fully developed incompressible turbulent boundary layer with zero pressure gradient. Vertical velocity disturbances which are periodic in the spanwise direction and restricted to small streamwise domains are assumed.

The …

Robot Force Velocity Control Using Expert System For Control Mode Changes, William R. Doggett

Electrical & Computer Engineering Theses & Dissertations

The most important property of an automated mechanical system is reliable execution of a specified task. Automated mechanical systems work best in precisely structured environments where all operations are repeatable. Typically, these systems are difficult to modify and expensive to install. Sensors can be used to detect disturbances, thus reducing hardware cost by offsetting the need for precise rigid construction components. Sensors, however, increase the complexity and cost of the control software. Efficient methods of reacting to sensor information during automated system operation are required to reduce software complexity and expense.

This thesis analyzes a robotic construction task and describes …

Elasto-Plastic Analysis Of Buried Pipelines Subjected To The Large Fault Movement, Luo-Jia Wang

Civil & Environmental Engineering Theses & Dissertations

The responses of buried pipelines subjected to a large fault movement are examined based upon a new non-linear cantilever beam analogy. This analogy assumes that the pipeline in the large deformation zone behaves like a cantilever beam subjected to a transversely concentrated shear at the inflection point and a uniformly distributed soil pressure along the entire span. Tangent modulus approach is adopted to analyze the coupled axial force-bending moment interaction effect on pipeline deformation in the inelastic range. Parametric studies of both tensile and compressive responses of buried pipeline to various fault movements, crossing angles, buried depths, pipe diameters and …

The Influence Of Reynolds Number And Atmospheric Effects On Aircraft Wake Vortices Near The Ground, Zhongquan Charlie Zheng

Mechanical & Aerospace Engineering Theses & Dissertations

Aircraft wakes represent potential hazards which can control aircraft spacing and thus limit airport capacity. Wake vortex trajectories and strengths are altered radically by interactions with the ground plane and by atmospheric conditions. This work has been concerned with developing more accurate numerical predictions. A two-dimensional, unsteady numerical-theoretical study is presented which has included viscous effects, the influence of stratification, crosswind and turbulence on vortex behavior near the ground plane, using a vorticity-streamfunction formulation.

A two-parameter perturbation procedure has been developed which uses analytic solutions for the initial flow field to accommodate the ground effect region in the numerical simulation. …

Competitive Enzyme Immunoassay By Polyclonal Antibodies Against Organophosphorus Pesticides, Kuo-Lan Wen

Theses and Dissertations in Biomedical Sciences

Organophosphorus compounds (OPs) comprise one of the major classes of pesticides in use today because they are highly effective and less toxic. Because of their extensive use, there is a need for monitoring OPs in water and vegetables. Gas chromatography (GC) is the usual method for OPs screening, but it is time-consuming and has the high cost of instrumentation. The goal of this project was to find an easy method which was sensitive and had less instrumentation required to test OPs.

Microwells and microtubes were utilized as the solid-phase immobilization for the development of an enzyme immunoassay for OPs. A …

A Performance Prediction Model For A Fault-Tolerant Computer During Recovery And Restoration, Rodrigo A. Obando

Electrical & Computer Engineering Theses & Dissertations

The modeling and design of a fault-tolerant multiprocessor system is addressed in this dissertation. In particular, the behavior of the system during recovery and restoration after a fault has occurred is investigated. Given that a multicomputer system is designed using the Algorithm to Architecture To Mapping Model (ATAMM) model, and that a fault (death of a computing resource) occurs during its normal steady-state operation, a model is presented as a viable research tool for predicting the performance bounds of the system during its recovery and restoration phases. Furthermore, the bounds of the performance behavior of the system during this transient …

Statistical Variations In Beach Parameter Change Rates For Walled And Non-Walled Profiles At Sandbridge, Virginia, Douglas Allen Bellomo

Civil & Environmental Engineering Theses & Dissertations

The interaction of seawalls {bulkheads) and beaches is a highly controversial subject today. In many locations all over the United States, seawalls have been both praised and ridiculed. It is well documented that Sandbridge, Virginia is, and has been, experiencing shoreline recession. Many believe however, that the recent construction of the seawalls has worsened this existing situation.

Fortunately, historical maps, and beach profiles are available to help determine if this is truly the case. The following defines several visible beach parameters, and describes how these parameters were calculated from two different data sources. Several methods and statistical techniques are then …

Effects Of Radiative Interactions In Molecular Gases Under Local And Nonlocal Thermodynamic Equilibrium Conditions, Manoj Kumar Jha

Mechanical & Aerospace Engineering Theses & Dissertations

Basic formulations, analyses, and numerical procedures are presented to investigate radiative heat interactions in diatomic and polyatomic gases under local and nonlocal thermodynamic equilibrium conditions. Essential governing equations are presented for both gray and nongray gases. Information is provided on absorption models, relaxation times, and transfer equations. Radiative flux equations are developed which are applicable under local and nonlocal thermodynamic equilibrium conditions.

The problem is solved for fully developed laminar incompressible flows between two parallel plates under the boundary condition of a uniform surface heat flux. For specific applications, three diatomic and three polyatomic gases are considered. The results are …

An Analysis Of The Response Of A Buckled Beam With Fixed Ends To An Harmonic Base Excitation Using The Finite Element Method, Peter John O'Donoghue

Mechanical & Aerospace Engineering Theses & Dissertations

A finite element formulation is developed to analyze the large deflection vibration of a buckled isotropic beam. The beam is buckled mechanically by an applied end displacement, and the dynamic loading is derived from the forced periodic base motion. The principle of virtual work is used to derive the system equations of motion. A Newton-Raphson iteration routine modified for the case of an applied end displacement is used with the incremental equations of motion to determine static deflection. The 0l time numerical integration algorithm is applied to the system of equations of motion in physical coordinates to determine dynamic response …

Navier-Stokes Simulation Of Quasi-Axisymmetric And Three-Dimensional Supersonic Vortex Breakdown, Hamdy A. Kandil

Mechanical & Aerospace Engineering Theses & Dissertations

Computational simulation of supersonic vortex breakdown is considered for internal and external flow applications. The interaction of a supersonic swirling flow with a shock wave in bounded and unbounded domains is studied. The problem is formulated using the unsteady, compressible, full Navier-Stokes equations which are solved using an implicit, flux-difference splitting, finite-volume scheme. Solutions are obtained for quasi-axisymmetric and three-dimensional flows. The quasi-axisymmetric solutions are obtained by forcing the components of the flowfield vector to be equal on two axial planes, which are in close proximity to each other. For the flow in a bounded domain, a supersonic swirling flow …

Grid Sensitivity For Aerodynamic Optimization And Flow Analysis, Ideen Sadrehaghighi

Mechanical & Aerospace Engineering Theses & Dissertations

An algorithm is developed to obtain the grid sensitivity with respect to design parameters for aerodynamic optimization. Two distinct parameterization procedures are developed for investigating the grid sensitivity with respect to design parameters of a wing-section as an example. The first procedure is based on traditional (physical) relations defining NACA four-digit wing-sections. The second is advocating a novel (geometrical) parameterization using spline functions such as NURBS (Non-Uniform Rational B-Splines) for defining the wing-section geometry. An inter-active algebraic grid generation technique, known as Two-Boundary Grid Generation (TBGG) is employed to generate C-type grids around wing-sections. The grid sensitivity of the domain …

Influence Of Processing Techniques On Copper Deep Levels Formation And On Photoconductivity In Silicon Doped Gallium Arsenide, Lucy M. Thomas

Electrical & Computer Engineering Theses & Dissertations

Diffusion of copper in silicon doped gallium arsenide under different diffusion conditions is studied. Copper compensated silicon doped gallium arsenide (GaAs:Si:Cu) is used as switch material for bulk optically controlled semiconductor switch, and on-state photoconductivity of the switch is primarily due to the properties of the copper deep levels introduced in the material during diffusion. Gallium arsenide being a compound semiconductor, presence of vacancies and defects make the study of diffusion a complex process. The objective of the current research is twofold: a) to study the influence of diffusion conditions and processing techniques on copper deep level formation in silicon …

Analysis Of Pultrusion Processing For Long Fiber Reinforced Thermoplastic Composite System, Wen Tso

Mechanical & Aerospace Engineering Theses & Dissertations

Pultrusion is one of the composite processing technology, commonly recognized as a simple and cost-effective means for the manufacturing of fiber-reinforced, resin matrix composite parts with different regular geometries. Previously, because the majority of the pultruded composite parts were made of thermosetting resin matrix, emphasis of the analysis on the process has been on the conservation of energy from various sources, such as heat conduction and the curing kinetics of the resin system. Analysis on the flow aspect of the process was almost absent in the literature for thermosetting process. With the increasing uses of thermoplastic materials, it is desirable …

Longitudinal Study Of Plasma And Erythrocyte Selenium Levels In Type I Diabetic Children During Development And Treatment Of Ketoacidosis, Pi-Hsia Fan

Chemistry & Biochemistry Theses & Dissertations

Most studies on the biological activity of selenium have focused on its role at the active site in the ubiquitous enzyme, glutathione peroxidase (GSH-Px) which catalyzes the removal of hydrogen peroxide and organic hydroperoxides (1). A connection between selenium deficiency and a wide range of diseases in animals and humans has been reviewed (2). Development of various forms of human cancer (3), failure of the immune system (4), as well as some cardiovascular diseases (5) have been reported or suspected to correlate with selenium deficiency. However, the physiological function of selenium in these different diseases is not fully understood, and …

Cross-Cultural Issues In The Management Of German-Owned Business Subsidiaries In Hampton Roads, Teja Ulrich

Engineering Management & Systems Engineering Theses & Dissertations

'Culture' can be described as patterns of thinking, feeling and acting that distinguish one cultural group from another. Cultural diversity is therefore likely to introduce variety to organizations in which individuals from different national backgrounds are working together. Although this variety bears the potential for an improvement of the cognitive development in the organizations, managers of multicultural business organizations tend to perceive cultural diversity as a disadvantage. This thesis attempts to identify the impact of cultural differences between Germans and Americans on organizations in which German managers work with American employees. German managers of eight business subsidiaries in the Hampton …