Engineering Commons^™

The Object-Oriented Design Of A Hardware Description Language Analyser For The Diades Silicon Compiler System, Lian Yang

Dissertations and Theses

This thesis is one of the first to introduce a systematic and general Source Language Analysis System (called SLA) for a high -level synthesis system.

Microstructural Characterization Of Rapidly Solidified And Extruded Ti-Al-Nb Alloys, Danny Joe Edwards

Masters Theses

"Two titanium alloys have been characterized using transmission and scanning electron microscopy, X-ray diffraction, and optical metallography techniques. Both of these alloys were rapidly solidified by melt spinning, the resulting ribbons pulverized, and the powders then extruded into cylindrical billets. The alloys are based on the compositions Ti-21.3Al- 9 Nb-0.6-Mo-2.6V and Ti-13.2Al-2.6Nb-0.5Mo-0.9V-0.5Zr-3.1B in atomic percent. The first alloy was examined in both the as-extruded condition and in the annealed condition (looo0c for 12 hours). The second alloy was examined in the as-extruded condition only.

For the first alloy, the as-extruded microstructure consisted of a B2 matrix with alpha-2 particles at …

Fluid Dynamics Of An Atomizer Nozzle, Bhaskar Sengupta

Masters Theses

"A pilot plant gas atomizer was designed and assembled at the Center of Pyrometallurgy, U.M.R., to produce metal powders. The pilot plant utilizes a confined, annular, supersonic nozzle to yield spherical metal powders (aluminum and zinc alloys have been atomized) of average size of 15μm in diameter.

A cold model of the atomizing nozzle was constructed to simulate the pilot plant. First, the high-speed gas flow was studied and later, modelling of the atomizing process was carried out by using water as the atomized liquid. This work has investigated the complex gas flow in the converging-diverging nozzle and around the …

Threaded Octree Structures For Fast Neighbor Voxel Processing In A Parallel Ray Tracer, B.R. Naveen Chandra

Dissertations and Theses

In the field of Computer Graphics, Ray Tracing has so far been the the best algorithm for rendering of realistic three dimensional images created by mathematical models. Ray Tracing is also known for its very large computation times, where the computation depends on the picture resolution, the number of objects and the complexity of the scene.

Spatial Control Of Crop Inputs Via Laptop And Typical Field Travel, Joseph Alan Schumacher

Electronic Theses and Dissertations

Field Grid Sense (FGS) is a system developed for use with a laptop computer to control crop production inputs. FGS can be used for spatially controlling and recording field inputs according to regional requirements within the field. Location is identified via the travel lanes formed during field operations. Grid areas within lanes are formed by measuring from the beginning of each lane to the start of each grid within the lane. Distance measurements are reset at the beginning of each lane in order to eliminate accumulated distance error in the field. A fifth wheel, which runs in the smooth path …

Exposure To Phosphine Gas During Application Of Magnesium Phosphide In Stored Product Warehouses, Mark Anthony Harrison

Theses and Dissertations

The use of phosphine gas requires that respiratory protection be used if exposures exceed the OSHA permissible exposure limit. As with other chemical exposures limits many of the references used to establish occupational health guidelines date back to the 1930’s and 1940’s. This is quite common and is the case with phosphine gas. Initial planning for fumigations involving magnesium phosphide requires that a hazard assessment be performed. Expected worker exposures based on previous monitoring or test data was not readily available. Many current practices and procedures for fumigations are based on recommendations from applicators who used the product in the …

An Extension Of Essentially Non-Oscillatory Shock-Capturing Schemes To Multi-Dimensional Systems Of Conservation Laws, Jay Casper

Mathematics & Statistics Theses & Dissertations

In recent years, a class of numerical schemes for solving hyperbolic partial differential equations has been developed which generalizes the first-order method of Godunov to arbitrary order of accuracy. High-order accuracy is obtained, wherever the solution is smooth, by an essentially non-oscillatory (ENO) piecewise polynomial reconstruction procedure, which yields high-order pointwise information from the cell averages of the solution at a given point in time. When applied to piecewise smooth initial data, this reconstruction enables a flux computation that provides a time update of the solution which is of high-order accuracy, wherever the function is smooth, and avoids a Gibbs …

The Importance Of Technology Assessment Procedures For Missionary Trainees, James Michael Hoeksema

Dissertations and Theses @ UNI

The purpose of this study was to identify those technology assessment (TA) procedures that are most important to teach to missionary trainees. This was based on the perceptions of the chief executive officers of U.S. Protestant mission agencies.

A survey was used to collect the research data. A total of 175 usable survey instruments were returned (25.6%). Analysis of the data consisted of frequency distributions and Chi-square.

A "common core" of TA procedures which are being used by mission agencies was identified. These were: (a) on-site field investigation, (b) committee meetings, (c) brainstorming, (d) personal interviews, (e) review of related …

Development And Validation Of A Model For Training Maintenance Supervisors For Productivity Improvements In Manufacturing Operations, Robert Reed Johnson

Dissertations and Theses @ UNI

The problem of this study was to develop and validate a training model for training maintenance supervisors. This training model focused on those areas, defined by industrial managers, where additional supervisory training was most likely to improve the performance of the maintenance departments.

Research of industrial and maintenance publications identified the maintenance function as having one of the lowest productivity levels in manufacturing organizations. Supervisor training was identified as a means to improve productivity in maintenance departments. An industrial survey completed by maintenance managers in manufacturing organizations in Iowa, Illinois, Minnesota, and Wisconsin identified those activities that were the responsibility …

Curricular Trends In Four-Year Baccalaureate Degree Industrial Technology Programs, Clayton Ray Diez

Dissertations and Theses @ UNI

The intents of the research were to determine both curricular trends in four-year baccalaureate industrial technology programs and the role accreditation standards have on such trends. The purpose was to present implications for future curriculum development and to provide a framework and point of reference for both curriculum developers and standards writers.

From the literature review, questionnaire items were designed to answer four research questions. The instrument was validated by a jury process and data were collected from 60 respondents, organized and compiled using National Association of Industrial Technology curriculum categories. Chi square and descriptive statistics were used to analyze …

Correlation Between Particle Velocities And Conditions Of Abrasive Waterjet Formation, Wei-Long Chen

Dissertations

The velocities of water and abrasive particles in abrasive waterjet(AWJ) were measured by the use of Laser Transit Anemometer(LTA). A setup for the velocity measurement was constructed and a statistical technique was used to improve the accuracy of the velocity determination. A comparison of the magnitude of velocities determined by LTA, Piezoelectric Force Transducer and Schlieren Photograph clearly indicates the feasibility of the use of LTA.

The velocities of water and particles were measured for different diameters of water and slurry nozzles, abrasive mass flow rates and particle sizes. The performed experiments enabled us to evaluate the effects of conditions …

Dynamic Behavior Of Co₂ Lasers, Li Zhang

Dissertations and Theses

Spontaneous pulsations have been observed in the output of a CO₂ laser. The temporal waveforms, transverse mode patterns, and laser lines are simultaneously measured under various operation conditions. The experimental data show that these pulsations have a direct connection with the transverse modes. We interpret the oscillations as being caused by mode beating, and the frequency shift of the oscillation as resulting from mode pulling. The theoretical explanations for these effects are in good agreement with the experimental results.

Endless State-Of-Polarization Control For Coherent Optical Communication Systems Using Nematic Liquid Crystal, Scott H. Rumbaugh

Dissertations and Theses

One of the obstacles to coherent fiber-optic communications is the unpredictable polarization drift which necessitates the use of an active polarization controlling system to match the polarizations of the signal and local oscillator. The polarization match must be maintained during the reset of any of the finite range components to prevent loss of data. We present a novel and practical system which uses three liquid crystal devices for the polarization matching process. Also, the required reset control algorithm and its derivation are described in detail.

Optimized Engine Out Procedures To Extend The Range Of Jet Transport Airplanes, Miltos Miltiadous

Master's Theses - Daytona Beach

The purpose of this study was to develop optimum engine-out procedures for the Boeing 747 and 767 on extended flights that will increase the range of the aircraft in case of engine failure. Theory suggests that an optimum amount of bank angle that will minimize drag resulting from asymmetric thrust in a multiengine airplane experiencing an engine failure, can be determined. By banking the airplane into the operative engines by that optimum bank angle, the range of the airplane can be improved significantly. Wind tunnel tests of both a Boeing 747 and a 767 model were performed to determine experimentally …

Investigation And Evaluation Of A Computer Program To Minimize Vfr Flight Planning Errors, Peter Joseph Mcalindon

Master's Theses - Daytona Beach

The purpose of this study was to investigate the effect of computer aided flight planning on flight planning errors. Subjects were selected from the introductory flight courses at Embry-Riddle Aeronautical University. After the subjects completed a conventional VFR navigation log, they were asked to plan the return trip of the flight using a computer aided flight plan. It was initially expected that the computer aided flight plans would have fewer flight planning errors than those calculated using conventional methods. The results supported the hypothesis that flight planning errors are greatly reduced when computer aided flight planning techniques are used.

Flotation Deinking Of Ultraviolet Radiation Cured Inks, Narayanasamy Seenivasan

Masters Theses

The objectives of this study were to optimize the variables of pH and surfactant concentration for the maximum flotation efficiency of ultraviolet radiation-cured inks and to increase the understanding of the behavior of the ink particles during flotation. Experiments were designed in two phases: water and ink system and water, fiber and ink system. At 7.t pH at room temperature the flotation efficiency increased with surfactant concentration to 8.2 <μ/>M/L and then dropped with increase in surfactant concentration. Statistical analysis showed that maximum flotation efficiency of 94.8% was obtained at pH of 7.56 at 12.18 <μ/>M/L surfactant concentration. Ink particles …

Application Of Risk Analysis In Investment Decision Making For New Products, Chul Paik

Masters Theses

This study presents the development of a quantitative model to deal with the decision to invest or not invest in the development and production of a new product. It is most applicable to new products which present a high probability of economic failure. The model employs only simple mathematics and statistics, so the decision maker can easily understand the model.

The model uses as input data three variables. These include: (1) the risk of product failure, (2) the maximum loss a company can afford in an investment, and (3) the estimated project cost. These three variables combined furnish as output …

Propagation Of Millimeter Wave Signals In Forests Using The Equation Of Radiative Transfer With Strong Forward Scattering Phase Functions, Nack Yang Cho

Dissertations

A forest is a highly scattering medium at millimeter wave frequencies. The propagation of cw millimeter wave signals in forests has been studied previously, both theoretically and experimentally. Published experimental data verified that continuous wave transmission is possible over lengths of the order of a few hundred meters and that a forest acts to strongly scatter energy in the forward direction. The cw studies yielded the determination of the range dependence, beam broadening effects and depolarization effects of millimeter wave signals in a forest. However, pulse broadening effects, which are of importance particularly in the case of digital signal transmission, …

An Approach To Pattern Recognition Of Multifont Printed Alphabet Using Conceptual Graph Theory And Neural Networks, Ihab A. Harb

Dissertations and Theses

This thesis describes an approach for accomplishing a pattern recognition task using conceptual graph theory and neural networks (NNs). The set of patterns to be recognized are the capital letters of six different fonts of the English alphabet, plus two shifted and six rotated versions of each. The letters are represented to the neural network on a 16x16 input grid (256 "sensor lines"). A standard classification encoding for such patterns is to use a 26-bit vector (26 lines at the NN's output), one bit corresponding to each letter. Experiments with such an encoding yielded results with poor generalization capability. A …

Investigation Of Flow Patterns In Various Wastewater Treatment Facilities, Thomas Joseph Martin Jr

LSU Historical Dissertations and Theses

The theoretical hydraulic retention time of wastewater treatment plants is often used to predict the efficiency of treatment and to calculate operational parameters. However, these values are related to the actual hydraulic retention time. When there is a large discrepancy between the actual and predicted values, the actual hydraulic retention time can be determined by marking a parcel of wastewater and recording its passage through the system. This investigation utilized rhodamine WT, a fluorescent dye, to track the movement of wastewater through a stabilization lagoon and a rock-reed filter. The loss of rhodamine WT to sorption, biodegradation and photodegradation was …

Optical Machine Recognition Of Lower-Case Greek Characters Of Any Size, Ivan X. D. D'Cunha

Electrical & Computer Engineering Theses & Dissertations

An algorithm utilizing a syntactic approach and a criterion based on normalized moments is defined for the reliable, automatic, machine recognition of handwritten and printed Greek characters of any size and font. In this approach a binary image of the character in question is obtained initially; its skeleton is then produced by utilizing a standard thinning algorithm. The classification process then incorporates the topological features of the characters such as existence of closed curves, number of intersections, number and location of free ends, axial symmetry, and the criteria derived from normalized moments to uniquely identify each pattern. Experiments conducted demonstrated …

The Electrical Characteristics Of Semi-Insulating Gallium Arsenide A Material For High Power Switches, David Clifton Stoudt

Electrical & Computer Engineering Theses & Dissertations

An experimental study of the electrical characteristics of semi-insulating gallium arsenide has been performed. The goal of this research was to aid in the development of an electron-beam controlled high-power semiconductor switch. The electrical characteristics were found to be heavily dependent on the deep level configuration of the material being investigated. Two methods of deep level characterization are discussed and their results are compared to the information given by the material manufacturer. Studies were conducted to determine both the steady-state and transient dark current characteristics of the switch. Along with being a function of the applied voltage and the deep …

Navier-Stokes Analysis Of Cold Gas Scramjet Nozzle-Afterbody Flowfields, Walter C. Engelund

Mechanical & Aerospace Engineering Theses & Dissertations

The recent renewal of interest in hypersonic aerodynamics, brought about largely in part due to the development of the National Aerospace Plane (NASP), is resulting in an increased reliance on computational fluid dynamics for flowfield data in this flight regime. The design of the nozzle-afterbody section for a hypersonic transport such as the NASP is currently underway, and is being conducted using both computational fluid dynamics and cold, non-reacting, simulant gas experimental models. In this study, a computational analysis is conducted for the flow through a scramjet nozzle-afterbody test section.

Computations have been performed for a cold gas simulation of …

Comparison Of Digital Controllers Used In Magnetic Suspension And Balance Systems, William Allen Kilgore

Mechanical & Aerospace Engineering Theses & Dissertations

Dynamic systems that were once controlled by analog circuits are now controlled by digital computers. Presented is a comparison of the digital controllers presently used with magnetic suspension and balance systems. The overall response of the systems are compared using a computer simulation of the magnetic suspension and balance system and the digital controllers. The comparisons include responses to both simulated force and position inputs. A preferred digital controller is determined from the simulated responses.

The Effects Of Bending On The Strain Distributions In A Stiffener-Skin Interface Region, Osvaldo F. Lopez

Mechanical & Aerospace Engineering Theses & Dissertations

An analytical and experimental study to assess the effect of bending on the adhesive strain distributions in a stiffener-skin interface region is described. A one-dimensional beam analysis is derived using a variational approach. Parametric studies are conducted to assess the effects of stiffener, skin, and adhesive thickness and adhesive material nonlinearity on the adhesive layer extensional and shear strain distributions subjected to applied bending. Two experimental methods of measuring through-the-thickness extensional strains in an adhesive are investigated. One method involves measuring the changes in the resistance of a composite strain sensor subjected to applied tension and compression loads. The second …

Application Of Shape Sensitivity Analysis For Computation Of Transient Free-Surface Flows, Frank Nicolas Michel

Mechanical & Aerospace Engineering Theses & Dissertations

Shape sensitivity analysis is introduced into a numerical scheme simulating a transient free-surface flow and applied to the case of a fluid advancing through a bed of cylinders. For this incompressible Newtonian flow, viscous forces are dominant. A penalty function finite element formulation is used to solve the problem. Coordinates of nodes on the moving boundary are chosen as design variables and an analytical formulation of the gradient of the finite element algebraic system, with respect to these variables, is derived.

In a numerical example, the results obtained with and without sensitivity analysis are compared. The efficiency and accuracy of …

Non-Linear Dynamics And Control For Thermal Room Models, Milind Prabhakar Oak

Mechanical & Aerospace Engineering Theses & Dissertations

Heating, Ventilation and Air Conditioning (HVAC) building operations with emphasis on reduced energy costs and occupant comfort require a dynamic control of short response (minutes) elements of HVAC systems. Hence, it is imperative to acquire better methods of non-linear modeling for prescription of thermal controls which will regulate space conditions over wide parameter ranges without undue cycling or steady state errors. A first step towards this goal is identification and inclusion of short response dynamics elements in the HVAC systems model while retaining essential non-linearities. A single zone environmental chamber is modeled in the heating mode. In the model, …

Domain Decomposition For Multigrid, Finite Volume Flow Solvers, Victor Robert Lessard

Mechanical & Aerospace Engineering Theses & Dissertations

Computing the flow fields about three-dimensional complex configurations accurately becomes a difficult task, if it is attempted to generate a single, body fitted grid with proper clustering. The domain decomposition methods, which divide the computational domain into less complex subdomains, are extensively used to decrease the grid generation workload. A domain decomposition technique also allows the use of different solution methods for different subdomains. The objective of this work is to develop a domain decomposition method via overlapping/embedding the component grids, which is to be used by upwind, multigrid, finite volume solution algorithms. A computer code, given the name MaGGiE, …

Synthesis Of An Efficient Band Mechanism For Robots And Prosthetic Devices, Run Chen Zhou

Mechanical & Aerospace Engineering Theses & Dissertations

A noncircular pulley has been applied to improve the system efficiency of an electrical-powered elbow prosthesis. The dynamics of the motor and the prosthetic arm have been incorporated into the kinematic synthesis relationships for determining the pulley profile that maximizes the efficiency of the elbow prosthesis.

The nonlinear dynamic equations have been solved by the code Differential Equation (DE) while determining the motor power and efficiency which are the criteria in the nonlinear programming problem. The optimal design variables for determining the pulley profile along with some simulation results have been obtained from an optimization program (based on the Generalized …

Manufacturing Workstation Model Using Petri Nets, Reni Alexander

Theses

Petri nets have become a powerful tool for modeling and analyzing asynchronous concurrent systems. In this thesis I apply Petri nets for analyzing and modeling a flexible manufacturing workstation (FMS). A manufacturing workstation is modeled by using Colored- Timed Petri nets, with the consideration of tool handling, raw materials, quality checking and the reuse of reworkable scraps. A simulation program for a simplified Petri net model of manufacturing workstation is described and the production throughput is computed.