Engineering Commons^™

In Situ Stem Technique For Characterization Of Nanoscale Interconnects During Electromigration Testing, Ismail Gobulukoglu, Brian W. Robertson

Department of Mechanical and Materials Engineering: Faculty Publications

A technique for observing microstructure and morphology changes during annealing or electromigration of 100 nm-scale and smaller interconnects is presented. The technique is based on dynamic in situ characterization using a UHV field-emission scanning transmission electron microscope (STEM) and can enable full microstructural characterization (images, diffraction patterns and compositions) during electromigration testing. Initial steps in the validation of the approach include in situ electron-beam OMCVD of Al-containing wires and observation of these wires. Although the deposition conditions were not optimized. Al-containing wires, with high edge acuity, thickness uniformity, and with minimum interconnect widths as small as 15 nm have successfully …

Finite Element Simulation Of Creep Buckling Of Cipp Liners Under External Pressure, Qiang Zhao

Doctoral Dissertations

The problem of long-term structural behavior of CIPP liners under external hydrostatic pressure has been characterized as a structural instability problem which is induced by time-dependent material deformation or creep. It is also a contact problem since the liner deflection is externally constrained by the host pipe. The intrinsically nonlinear problem is investigated by means of finite element simulation, with emphases on (a) the essential structural behaviors and mechanisms of buckling, and (b) the influences of inelastic material properties (i.e. yield strengths and creep rates) and geometrical parameters on liner's buckling resistance.

A liner first deforms as a free pipe …

An Empirical Investigation On The Impacts Of Ground-Level Ozone Concentrations On National Ambient Air Quality Standards: The Case Of Lake Charles, Louisiana, Benedict Nweke Nwokolo

Doctoral Dissertations

This study presents information upon which the state of Louisiana can base its ozone State Implementation Plans (SIPs) designed to achieve planned emissions reduction that are required by the Clean Air Act (CAAA) of 1990. The research investigation included an assessment survey on a number of Transportation Control Measures (TCMs) and their degree of acceptability by the residents of Lake Charles area of Louisiana, the research target area. The TCMS were first ranked on the basis of people's perception of each TCM and four TCMs were later analyzed for cost-effectiveness using computer mathematical models. The Traffic Flow Improvements TCM was …

We Live In The Best Of Possible Worlds: A Proof, Guoqing Liu, Vladik Kreinovich

Departmental Technical Reports (CS)

It is well known that equations of motions and equations which describe the dynamics of physical fields can be deduced from the condition the action S (determined by the corresponding Lagrange function) is optimal. In other words, there is an optimality criterion on the set of all trajectories, and the actual trajectory is optimal with respect to this criterion.

The next reasonable question is: where does this optimality criterion on the set of all trajectories (i.e., the corresponding Lagrange function) come from? It is reasonable to assume that (similarly) on the set of all Lagrange functions, there is an optimality …

Optimization Of A Vortex Generator Configuration For A 1/4-Scale Piper Cherokee Wing, Kerri A. Raykowski

Master's Theses - Daytona Beach

Several sets of wind tunnel tests were performed to determine an optimum vortex generator configuration for a 1/4-scale model of the Piper Cherokee wing. Several variables were incorporated into this experiment in an effort to determine their influence on vortex generator performance enhancement (or degradation). Vane type vortex generators were used with 3 different leading edge sweeps: zero (rectangular planform), 20, and 45 degrees. Three different vortex generator heights were tested (0.05”, 0.1”, and 0.2”) to find the optimal vortex generator height relative to the local boundary layer thickness. The vortex generator angle of incidence relative to the freestream was …

Culture And The Management Of Advanced Automation: An Analysis Of Two Airlines, Surendra Cudah Ratwatte

Master's Theses - Daytona Beach

The purpose of this study was to investigate the relationship between National, Organizational and Professional Cultures and the attitudes toward managing advanced automation among the flightcrew of two international airlines. The Flight Management Attitudes Questionnaire developed by the University of Texas was utilized to determine the attitudes and perceptions held by airline pilots of various nationalities who fly late model Airbus and Boeing airliners. A census survey was conducted at the crew bases of the two airlines, one in the Middle East and other in South Asia. A total of 230 completed surveys were received. Chi Square analysis was used …

On The Detachment Of Step-Tapered Doublers: Part 2—Evolution Of Pressure Loaded Structures, Anette M. Karlsson, W. J. Bottega

Mechanical Engineering Faculty Publications

One-dimensional edge debonding of layerwise step-tapered patches from both flat and cylindrical structures subjected to applied pressure is studied in the context of the general formulation presented in Part 1. Numerical simulations based on analytical solutions of the problems of interest are performed and intricate results presented in the form of threshold curves/delamination paths for various taper angles and support conditions. Configurations corresponding to full contact of the debonded segments, edge contact of the debonded segments and no contact of the debonded segments of the evolving composite structure are included in the model and found to significantly affect the predicted …

On The Detachment Of Step-Tapered Doublers : Part 1—Foundations, W. J. Bottega, Anette M. Karlsson

Mechanical Engineering Faculty Publications

One-dimensional edge debonding of layerwise step-tapered patches from both flat and cylindrical structures is examined. The problems are approach from a unified point of view, as propagating boundary problems in the calculus of variations, with the models for both flat and curved structures being formulated simultaneously. The effects of a contact zone adjacent to the bonded region are incorporated as is the phenomenon of edge-point contact. The formulation results in a selfconsistent representation of the various intact and debonded segments of the composite structure comprised of a multilayer patch and a base structure. It concurrently yields the conditions which establish …

Reduction Of Helmet Buffeting In Open Cockpit, Single Seat Race Cars, Mark Vallon

Master's Theses - Daytona Beach

At speeds approaching 240 mph, drivers of open cockpit race cars frequently experience large aerodynamic forces which act on the helmet. These forces, specifically the aerodynamic buffeting of the helmet, reach levels which are very fatiguing and distracting to the driver, and are therefore unacceptable. Little investigation has been done in this area, because normal wind tunnel tests do not isolate the helmet from the rest of the car. During this project, measurements of aerodynamic forces acting on a helmet inside a race car cockpit were made to determine the cause of the buffeting, and to determine possible improvements.

Tests …

Cracking In Cycloaliphatic Epoxy/Aluminum Composite Electrical Bushings, Keith Alan Parker

Doctoral Dissertations

The problem of cracking in electrical apparatus bushings as a result of thermal stresses was investigated. The bushings were composed of cycloaliphatic epoxy insulators with embedded aluminum conductors. The problem is due to the difference in coefficients of thermal expansion of the two materials. A solution to the problem had been to coat the conductors before they were formed together with the epoxy insulators. The coating was assumed to prevent cracking by allowing movement between the two materials as their dimensions changed during thermal expansion and contraction. The contribution of the coating was to be established.

The hypothesis was that …

Multifield Spectral Analysis Of Human Respiratory Sounds, John William Ray Jr.

Doctoral Dissertations

Computer analysis of human respiratory sounds (phonopneumography) has been attempted since the 1960s with poor results. Steady research efforts by numerous researchers have failed to yield a practical diagnostic tool to replace the physician and the stethoscope. This has been the result of the high degree of variability in proposed analysis parameters from subject to subject.

The purpose of this research is to examine a new approach to phonopneumography by comparing multiple lung fields of the same subject for the same breath in order to develop the diagnostic parameters. This approach has the advantage of allowing the subject to provide …

Graphical Display And Data Structure For Virtual Prototyping, David William Manry

Doctoral Dissertations

One of the goals of engineering firms is to bring better products to market faster. Although concurrent engineering can aid in this endeavor, it requires that all areas of an organization work simultaneously. Thus, current product data must be accessible to everyone.

Virtual prototyping allows this simultaneous exchange of information. Virtual prototyping not only replaces the physical model in product development with a virtual model, but also it goes further by allowing data associated with each part of the model to be accessed. This data is not limited to just geometric properties but could contain other quantifiable properties, such as …

Comprehensive Analysis Of Edge Detection In Color Image Processing, Shu-Yu Zhu, Konstantinos N. Kostas Plataniotis, Anastasios N. Venetsanopoulos

Electrical Engineering and Computer Science Faculty Publications

Various approaches to edge detection for color images, including techniques extended from monochrome edge detection as well as vector space approaches, are examined. In particular, edge detection techniques based on vector order statistic operators and difference vector operators are studied in detail. Numerous edge detectors are obtained as special cases of these two classes of operators. The effect of distance measures on the performance of different color edge detectors is studied by employing distance measures other than the Euclidean norm. Variations are introduced to both the vector order statistic operators and the difference vector operators to improve noise performance. They …

An Investigation Into The Skills Needed For The Workforce In The Year 2005 For Midwest Manufacturing, George A. Ritland

Graduate Research Papers

The purpose of this study was to define the collaborative skills identified by John Deere and provide the personnel who are involved in the hiring process at John Deere those results in order to assist them in evaluating potential employees for employment in the year 2005.

On-Line Free Form Surface Measurement Via A Fuzzy-Logic Controlled Scanning Probe, Ming Chang, Paul P. Lin

Mechanical Engineering Faculty Publications

This paper presents a system and methodology for on-line free form surface measurement via a scanning contact probe installed on a CNC (computer numerical control) machine. The scanning probe provides more sampling points than any traditional touch trigger type of probes used on CNC machines, and better measuring accuracy than laser displacement sensing or structured lighting. The presented measuring system's main advantage is that the number of measured points can vary with the change of surface curvature. To improve the measuring stability and continuity, fuzzy logic control, in lieu of traditional PID control, is employed. As a result, the …

Frequency Driven Phasic Shifting And Elastic-Hysteretic Partitioning Properties Of Fractional Mechanical System Representation Schemes, Jerzy T. Sawicki, Joe Padovan

Mechanical Engineering Faculty Publications

Based on the Louiville–Riemann fractional formulation of lumped hysteretic mechanical system simulations, asymptotic-type relationships are derived. These are employed to determine how such operators, which act as viscoelastic elements, partition system energy into conservative and nonconservative components. Special emphasis is given to: (a) determine how operator order serves to weigh such a splitting, (b) determine how partitioning affects system phasing and amplitude response, and (c) to establish how conservative and nonconservative effects modulate during a given system cycle. The generality of the undertaken approach is such that multi-element fractional Kelvin Voigt formulations subject to spectrally rich inputs can be handled, …

Routing And Scheduling I/O Transfers On Wormhole-Routed Mesh Networks, Bhagirath Narahari, Sunil Shende, Rahul Simha, S. R. Subramanya

Electrical and Computer Engineering Faculty Research & Creative Works

This paper studies the problem of routing and scheduling parallel I/O operations to minimize the time required to transfer data between processors and I/O devices. In particular, a 2-dimensional mesh architecture is considered in which routing is performed using wormhole switching and I/O nodes are placed on the periphery of the mesh. Two broad classes of data transfer mechanisms are examined: schedules with blocking (SB), in which packets may be temporarily blocked during transit, and schedules with no blocking (SNB), in which packets are never blocked in the network. For both classes, optimal scheduling is shown to be NP-complete, and …

Preparation And Surface Studies Of Negative Electron Affinity Semiconductors Photocathodes, Khaled A. Elamrawi

Electrical & Computer Engineering Theses & Dissertations

Fabrication of high quantum efficiency, long lifetime negative electron affinity photocathodes is important for applications such as photomultipliers, image intensifiers, electron beam lithography, electron microscopy, and polarized electron sources. The surface cleanliness of the III-V semiconductor photocathode is crucial in obtaining high photosensitivity.

GaAs(100) and InP(100) photocathodes are prepared by atomic hydrogen cleaning. The cleaning effect on the photocathode performance is discussed. The surface degradation mechanisms which reduce the photocathode lifetime are presented. The photocathode surface cleanliness, structure, and morphology are studied using reflection high-energy electron diffraction (RHEED).

Quantum efficiencies of ∼14% and 8% are obtained for GaAs and InP, …

Development And Testing Of An Ac Micro Hollow Cathode Simulator, Thomas E. Caldwell

Electrical & Computer Engineering Theses & Dissertations

The use of AC source plasma discharge devices in applications such as material processing and film deposition has increased in recent years due to improvements in discharge efficiency made possible by devices such as the micro hollow cathode. Designing hollow cathodes for specific applications requires an understanding of the processes that govern the discharge. Simulation is an inexpensive tool for understanding hollow cathode operation and optimizing the device for specific applications. This thesis describes the development of an AC micro hollow cathode simulator. It details the theoretical models used in the simulation and presents the results of test cases intended …

Stability Analysis And Augmentation Of A Closed-Loop Computer Control System Subject To Electromagnetic Disturbances, Mustafa Doğan

Electrical & Computer Engineering Theses & Dissertations

Most electronic and electrical equipment is not only a potential source of electromagnetic interference (EMI) but can also malfunction when exposed to certain levels of ambient EMI. This phenomena becomes more significant for digital control-computers automating the command and control performances in complex plants. Such EM disturbances can introduce transient signals on analog sensor and actuator lines, change data values on digital buses and in memory, or even produce logic changes in the CPU. The result of these so called computer upsets is the introduction of some degree of degradation in the quality of the control signal ranging from a …

Stability Of Three-Dimensional Compressible Boundary-Layers, Samarasingham Jeyasingham

Mechanical & Aerospace Engineering Theses & Dissertations

The failure repair process of a continuously operating device is studied in this research. Different cases that incorporate modeling of equipment deterioration, inspection, and maintenance for optimal maintenance policy are proposed. Markov processes are used to determine state probabilities, and the optimal value of the mean time to preventive maintenance is determined by maximizing the availability of the equipment with respect to the meantime preventive maintenance. The approach uses models that assume that equipment can fail due to both deterioration and random failures. Preventive maintenance can be performed from each working state to avoid deterioration failure. Economic effects are integrated …

Relationship Between Cost Of Technical Training And Cost Reduction Of Internal Defects At John Deere Waterloo Foundry, John Brackin

Graduate Research Papers

Can the cost of technical training at John Deere Waterloo Foundry pay for itself in the reduction of internal defects? This research compared training costs to the savings from reduced internal defects on Molding Unit 801 located in the John Deere Waterloo Foundry. Training was the independent variable of this research. The results of this research identified a correlation between training costs ( operational definition on page 10) and defect reduction costs. A correlation between these two established a break even point for training dollars spent.

The dependent variable was the dollar savings based on reduction of internal defects. There …

Three Reasons To Broaden Your Fertigation Knowledge, Charles M. Burt

BioResource and Agricultural Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

1999 (Spring) Ensi Informer Magazine, Morehead State University. Engineering Sciences Department

ENSI Informer Magazine Archive

The ENSI Informer Magazine published in the spring of 1999.

Stratal Architecture In A Prograding Shoreface Deposit, Eastern Shore, Va: Relationship To Grain Size, Permeability, And Facies Distribution, Andrew C. Miller

OES Theses and Dissertations

A fundamental concern of the stratigrapher is to develop predictive models of stratigraphic organization. In sedimentology one of the most significant problems that has yet to be resolved is the fact that there is a lack of quantitative information regarding the relationship between geometry of beds, thickness of beds, grain size and sedimentary structures in sandy environments, especially shallow marine deposits. Scientists have also realized the need to correlate quantitative permeability to sedimentary structures and scales of stratigraphic organization. The purpose of the study is to investigate the scales of stratigraphic organization that control the variation of grain size and …

Development Of Baseline Water Quality Stormwater Detention Pond Model For Chesapeake Bay Catchments, William J. Musico

Civil & Environmental Engineering Theses & Dissertations

A stormwater detention pond model, EEMD (Environmentally Economic Management Design), was developed using VisualBasic to facilitate the design of extended detention basins. A detention basin is a design such that a site's stormwater runoff would meet certain environmental impact requirements. To ensure these environmental requirements are meet the Commonwealth of Virginia subscribes to the procedures outlined by the Chesapeake Bay Local Assistance Department (CBLAD).

The purpose of the Chesapeake Bay Local Assistance Department (CBLAD) Calculation Procedures is to ensure that the development of constructed areas do not further exacerbate current problems of stormwater-induced eutrophication and downstream flooding. The methodology is …

Interval Matching And Control For Hexahedral Mesh Generation Of Swept Volumes, Jason F. Shepherd

Theses and Dissertations

Surface meshing algorithms require certain relationships among the number of intervals on the curves that bound the surface. Assigning the number of intervals to all of the curves in the model such that all relationships are satisfied is called interval assignment. Volume meshing algorithms also require certain relationships among the numbers of intervals on each of the curves on the volume. These relationships are not always captured by surface meshing requirements. This thesis presents a news technique for automatically identifying volume constraints. In this technique, volume constraints are grouped with surface constraints and are solved simultaneously. A sweepable volume has …

Magnetic And Mössbauer Spectral Study Of Mixed Valent La₀.₂Sr₀.₈Cu₀.₂Fe₀.₈O2.68 And Related Perovskites, Gary J. Long, Dimitri Hautot, Amitabh Mohan, Ingeborg Kaus, Harlan U. Anderson, Fernande Grandjean

Chemistry Faculty Research & Creative Works

The La_0.2Sr_0.8Cu_1-xFe_xO _3-δ perovskites are important because they are mixed electron and oxygen anion conductors and thus are able to serve as dense oxygen separation membranes. In order to better understand the mechanism for this separation a Mössbauer spectral study has been carried out to determine the ratio of iron(III) to iron(IV) in these mixed valent compounds. The Mössbauer spectra of La_0.2Sr_0.8Cu_0.2Fe_0.8O _3-δ obtained between 4.2 and 78 K reveal that its Néel temperature is ~75 K and the two well-resolved magnetic sextets observed …

Evaluation Of Lead Anode Reactions In Acid Sulfate Electrolytes. I. Lead Alloys With Cobalt Additives, Pu Yu, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

Lead alloys, such as lead-calcium-tin and lead-silver, are the primary insoluble anodes used in the electrowinning of metals. While some difficulties are encountered in their use, there is no obvious replacement that is economically and technically competitive. Two of the specific problems with lead include decreased cathode purity due to incorporation from corrosion products and the relatively high overpotential which increases cell voltage. To gain an improved understanding of the fundamental behavior of lead anodes, the polarization behavior of six different alloys in sulfuric acid was evaluated. Some tests were also made with Co(II) in the acid sulfate electrolyte. Notable …