Engineering Commons^™

Dynamics Of Ultrashort Pulse Generation And Amplification In Dye Lasers, Shuanghua Jiang

Dissertations and Theses

The dynamics of ultrashort pulse generation and amplification in dye lasers is studied in this dissertation. In particular, we have developed general semiclassical models for ultrashort pulse dye laser amplifiers and oscillators. These models start from Maxwell's equation for the electric field and density matrix equations for the active laser medium. A finite coherence time or phase memory time of the molecular wave functions, a finite vibrational relaxation time for the lower electronic state of the dye laser transition, an isotropic molecular orientational distribution, and an arbitrary pump polarization are all taken into account. Based on these models, specific topics …

Cause And Effect Diagrams For Process Analysis And Control, Philip Thomas

Theses

Cause and effect diagrams can be used as an effective tool for identifying the possible causes of a quality problem. Using this diagram one can go deep into the causes of the problem and take proper remedial action. Several graphical techniques like matrix diagrams, systematic diagrams, etc., can be combined with this tool to better represent the cause effect relationships. While a quantitative approach of this technique is feasible but limited, there are useful applications based on qualitative approach to this technique. The objective of this thesis is to propose a quantitative approach to the cause and effect diagrams especially …

Design Of Holographic Optical Interconnections, Su-Chiou Tsay

Theses

Optics have many advantages over electronics in interconnecting systems together, particularly in terms of higher transmission speed and better immunity to noise. Optical interconnections may be used at all levels of computing: for local area networks, between processors or memory elements, and between boards.

In this thesis, we attempted to generate a new type of computer hologram for optical interconnection purposes. The holographic method is very promising whenever integrated optical interconnections are considered. In this research we have tried two designs: the shortest path grating design which can maximize the global output energy and the single input maximum output grating …

Phosphorus Accumulation In Bottom Sediments Of Retention/Detention Ponds, Kriss Young Kaye

Retrospective Theses and Dissertations

Laboratory and field studies were conducted to characterize phosphorus in bottom sediments for retention/detention ponds. The laboratory studies, including batch and column experiments, were conducted to assess possible removal processes. Sediment core samples were collected from detention ponds receiving urban runoff. These cores were analyzed for phosphorus at different layers including accumulated top sediments and the lower parent soil beneath it at a depth of 1, 3, 5, 10 and greater than 10 cm. The phosphorus accumulation rate was found to decline with calculated overflow rates from an average storm. Also attenuation of phosphorus with sediment depth followed an exponential …

Measuring And Compensating For Transport Delay In Real-Time Interactive Driving Simulation, Joseph D. Dumas Ii

Retrospective Theses and Dissertations

Real-time, man-in-the-loop simulators are important tools for operator training as well as human performance research. Simulator implementation using digital computers offers many important advantages but may also cause problems. One of the most significant and troublesome artifacts of digital computer simulation is the presence of transport delays in the operator/vehicle control loop. Transport delays have been shown to destabilize the system, resulting in poorer control of the simulated vehicle. They may also contribute to an increased likelihood of simulator sickness in human operators. Therefore, it is desirable to be able to quantify simulator transport delays and to compensate the system …

Design And Construction Of Maintainable Knowledge Bases Through Effective Use Of Entity-Relationship Modeling Techniques, William Yancey Pike

Retrospective Theses and Dissertations

The use of an accepted logical database design tool, Entity-Relationship Diagrams (E-RD), is explored as a method by which conceptual and pseudo-conceptual knowledge bases may be designed. Extensions to Peter Chen's classic E-RD method which can model knowledge structure used by knowledge-based applications are explored. The use of E-RDs to design knowledge bases is proposed as a two-stage process. In the first stage, and E-RD, termed the Essential E-RD, is developed of the realm of the problem or enterprise being modeled. The Essential E-RD is completely independent of any knowledge representation model (KRM) and is intended for the understanding of …

Consumption And Loss Of Formaldehyde In Electroless Copper Plating, Peter John F. Sutch

Retrospective Theses and Dissertations

The objectives of this research were to quantify formaldehyde consumption due to plating and parasitic reactions and determine the magnitude and distribution of formaldehyde losses from the electroless copper plating process. Plating and rinse bath samples obtained from three electroless copper plating operations were analyzed for formaldehyde and copper in order to develop a mass balance analysis about the plating bath for periods of active production and no production. Fugitive air and stack releases of formaldehyde were estimated using emission factors developed from air sampling at the three facilities. It was determined that approximately 90% of the formaldehyde added to …

Elastic Impact Of Beams On Gap-Spring Supports, Hany Aly Abdelhafiz

Archived Theses and Dissertations

No abstract provided.

Roller Compacted Concrete As A New Method For Building Dams And Its Economic Advantages, Sami Tannous

Electronic Theses & Dissertations

This document includes overviews of the planning and design processes, reviews of construction operations, evaluations of the behavior, and performance of completed dams. Included in this document are examples of roller-compacted concrete dam construction in the U.S., South America, Europe, Asia, and Australia. This document also provides information on the development of roller compacted concrete (RCC) to support the use of RCC in dam construction. This procedure offers rapid construction with a lower cost, compared with the traditional concrete practice, and challenges the economics of earthfill and rockfill embankment dams.

The Development Of A Solar Radiation Extinction Correction For Satellite Data, Widad I. Mohamed

Electronic Theses and Dissertations

The main objectives of this thesis are the following: 1) Remove the haze using water surfaces in Landsat satellite imagery of the visible and near-infrared regions for their properties of high absorption of solar radiation and weak reflection of it. The scattered solar radiation is most obvious in dark weakly reflecting regions such as water. The haze removal technique depends on subtraction of scattered light from picture elements within the satellite imagery. 2) Derive a formula and techniques for a given image to correct for extinction by transforming the observed intensity of the signal transmitted to the Landsat detector to …

Design And Evaluation Of An Augmentative Communication Aid For Multiply Impaired Individuals, Mark S. Annett

Theses and Dissertations

Individuals with sensory and multiple physical impairments, which may include the loss of the ability to speak, have very specialized communication needs. Based on the belief that the current technology does not fully meet these needs, a prototype communication aid was developed for an individual who is cortically blind, dysphonic, and motor impaired. Furthermore, the communication device has broader applications beyond the present individual.

The prototype system has a direct selection of "Yes" and "No" responses, scanning access to daily phrases, rate enhancement of all scans, prompted encoding for selection of letters, two letter codes for complete sentences, access to …

A Model Of Electronic Warfare Systems Acquisition And Engineering For Saudi Arabia, Negaa M. Albegami

Doctoral Dissertations

"A major activity within the systems engineering process is the requirements definition and analysis phase. In technical systems, planning this phase looks too technical for top management and too broad for the engineers specialized in narrow technical fields. This categorization (too technical/too broad) represents a gap between top management and specialized engineering. In Saudi Arabia, such a gap is believed to be very wide.

The main objective of this research is to find a way to narrow this gap between management and engineering when planning government systems, especially in electronic warfare (EW) systems. A solution in this effort is to …

Theoretical Results Supporting The Use Of Passive Damping As Augmentation To The Active Control Of Flexible Structures, Joseph Vincent Harrell

Mechanical & Aerospace Engineering Theses & Dissertations

One challenge of modern control technology is how to control a flexible structure with accuracy, speed, and economy of effort. Controlling a structure with many degrees of freedom by purely active means implies the implementation of inordinate sensors and actuators and creates the need for numerous calculations that must be done instantly. Experiments have shown that practical structures under active control alone can suffer instabilities due to modal vibrations beyond the bandwidth of the active controller. Furthermore, if there is a high degree of model uncertainty, instabilities can be produced by inputs of modal vibrations not occurring in the system …

The Use Of A Factory Simulation To Evaluate A Flexible Control Structure For Integrated Manufacturing, Ling Ling Pan

Engineering Management & Systems Engineering Theses & Dissertations

Once a control structure for an integrated manufacturing system is decided upon, manufacturing activities are limited by that structure. A flexible control structure is presented as an approach for accommodating a variety of manufacturing activities, without being limited to a single control structure. A flexible control structure is one that allows multiple types of control structure in the manufacturing process. For example, both hierarchical and non-hierarchical structures may be used in a flexible structure. The properties of a flexible control structure are discussed from the point of view of graph theory.

Control structures for automated manufacturing are difficult to evaluate …

A Comparison Of Minority And Non-Minority Engineering Students On Selected Personality And Program Variables, Thomas Mercer Collier Jr.

Theses and Dissertations in Urban Services - Urban Education

The purpose of this study was to investigate whether there are common characteristics associated with 226 Hispanic, African American, and White engineering students who persist at predominantly White colleges and universities. A personality profile of minority and non-minority engineering students was developed. Information regarding factors influencing choice of major, university, study, work and extracurricular involvement, possible reasons for withdrawal from college, awareness and satisfaction with student support services and selected academic courses was also compiled. Components of Minority Engineering Programs (MEPs) which are most used or valued by minority engineering students were identified.

Analysis of Variance identified four of the …

Reliability Trend Analyses With Statistical Confidence Limits Using The Luke Reliability Trend Chart, Stephen R. Luke

Engineering Management & Systems Engineering Theses & Dissertations

In electronic systems, it is interesting to understand exactly how the reliability is changing with time. Dynamic performance changes when a system passes from infant mortality stage into useful life phase and when the system passes from useful life phase into wearout phase. Dynamic performance also changes when the system is redesigned or when the system is acted on by a number of other outside forces such as a change in maintenance policy, escalation of alignment problems, or a change in training program. It is important to know when a system is changing dynamically in order to assess design, policy …

Diffusion Of Total Quality Management: An Organizational Self-Production Perspective, Baizhong Zhao

Engineering Management & Systems Engineering Theses & Dissertations

American industries are in the process of a quality revolution. Most companies are busy implementing Total Quality Management (TQM) programs. However, the experience of both Japanese and American companies indicates that successful TQM implementation depends on an understanding of implementation processes, which itself relies on an understanding of organizational self-organizing, for it is through this process that TQM gets diffused and becomes a core component of an organization's culture. Self-organizing is a so-called process-oriented approach, based on theory from cybernetics (Ashby, 1962; Steier & Smith, 1985; von Foerster, 1960), dissipative structure theory (Prigogine & Stengers, 1984), and chaos theory (Gleick, …

Multidimensional Approach To Implementation Of Continuous Process Improvement Utilizing Small Run Analysis In A Shipyard Environment, Paul Ray Hollandsworth

Engineering Management & Systems Engineering Theses & Dissertations

Nationally, both public and private shipyards are experiencing a high rework rate (over 40%) in the fabrication of plug connectors used for electronic systems onboard Navy vessels. The shipyard's survival depends on acquiring the elements necessary to maintain a major industry in a position of continuous improvement that produces a better product than their competitors, at less cost, in a safe manner, and on schedule.

This research addresses the complex problem of how to introduce quality control methodologies within a job shop environment that assists in identifying variables that influence the rework rate of plug fabrication process over a four …

Cultural Transposition: Exploring Meanings Of And Strategies For Cross-Cultural Transfer Of Organizational Practices, Yongming Tang

Engineering Management & Systems Engineering Theses & Dissertations

The research objective is to study the phenomenon of transferring organizational practices which are conceptualized in one culture to another different culture. The purpose of the study is (1) to understand how cultural values and beliefs are manifested in behavior; (2) to explore how the Western organizational practices are interpreted and assimilated into an organization in an Eastern culture; and (3) to explore strategies for the fit between local cultural orientations and imported organizational practices. A qualitative, interpretive, and reflexive research methodology was developed to conduct this study.

The study was conducted in two phases. The first phase was designed …

Weapon System Integration For The Afit Virtual Cockpit, William E. Gerhard Jr.

Theses and Dissertations

The Air Force Institute of Technology is continuing research in the Virtual Cockpit. The Virtual Cockpit makes use of high performance graphics workstations, Virtual Environment technology, and Distributed Interactive Simulation network protocols to create a flight simulator based on the capabilities of the McDonnell Douglas F-15E Strike Eagle. The work presented in this thesis focuses on the design and implementation issues for integrating a weapons delivery capability. Weapons simulated include: RADAR and IR guided air- to-air missiles, gravity and precision guided bombs, and a 20mm cannon. Virtual Environment displays used include: color NTSC and monochrome high resolution helmet mounted displays …

Galvanic Stripping Of Fe⁺³ And Pb⁺² Ions And Dissolution Of Metallic Fe, Zn, Pb And Cd Using Di(2-Ethylhexyl)Phosphoric Acid, Luis Miguel Chia Aquije

Doctoral Dissertations

"Two systems were evaluated using the principles of the galvanic stripping process. One of them, the removal of Pb⁺² ions from di-2(ethylhexyl) phosphoric acid (D2EHPA) was performed using metallic zinc. The other, the removal of Fe⁺³ ions from D2EHPA used metallic iron as reductant and was performed simultaneously with the organic phase using a slightly acidic aqueous solution of hydrochloric acid. In addition, the dissolution of metallic zinc, iron, lead, and cadmium in D2EHPA was studied in order to better understand the anodic step in the mechanism of the galvanic stripping process.

Increased temperature was found to dramatically …

Turbomachine Stability And Forced Response Prediction, Leland Bert Clark

Open Access Theses

A mathematical model is developed and utilized to analyze turbomachine cascade flutter and forced response. The flutter boundary, defined as the largest value of reduced frequency at which flutter occurs for a given cascade, was evaluated for single degree of freedom torsional oscillation as well as coupled bending and torsional oscillations. The maximum amplitude of forced response in bending and torsion was also considered. The unsteady aerodynamic lift and moment coefficients were determined from unsteady aerodynamic flow models for subsonic flow, supersonic flow with a subsonic axial component and supersonic axial flow. The effect of changing the Mach number, stagger …

Utilizing Instructional Design Constructs To Enhance Computer-Based Instruction In Air Traffic Controller Training, Theodore Scott Rhoads

Master's Theses - Daytona Beach

This study demonstrates that a computer-based instructional design format is appropriate for novice air traffic control (ATC) training. The computer presents the student with small amounts of information in tutorial and drill and practice sequences that necessitate student interactivity. The student is then periodically audit tested to ascertain mastery of the subject matter. The result of these mid-lesson evaluations serve as a self-check so that the student can assess his/her progress in the learning cycle. The systematic design of instruction and interactive approach to learning, enhances student motivation, improves learning and retention, while placing the responsibility of achieving specific learning …

Selection And Implementation Of A Cad/Software System For Navigator Boats, Brian J. Finzel

Honors Capstone Projects and Theses

No abstract provided.

Semiconductor P-N Junction Space Charge Region Capacitance, Mohammad Humayun Habib

Dissertations and Theses

The classical capacitance voltage characteristics based on the depletion approximation, is adequate at reverse bias, but introduces errors at high forward bias. Because of its inherent simplicity and compactness this classical depletion model is well studied and widely used in circuit simulators. In this work, a new model for the semiconductor space charge region (SCR) capacitance, based on physical justification, will be derived. This new model takes three input parameters, C0 , Vbi and m, thus eliminating the fitting parameter FC currently used in SPICE. This new model is applicable for any applied voltage and will be compared with the …

Thermally Induced Vibration Of A Cross-Ply Laminated Plate With Hygrothermal Effects (Exact Solution), Stephen Jerry Maerz

Master's Theses - Daytona Beach

Of increasing importance in structural design is the use of fiber-reinforced polymeric composite material, notably in advanced aircraft and projectiles. These applications expose the materials to varied environmental conditions, therefore the material performance under these conditions is of great interest. One aspect of this is the solution of the dynamic response of a composite structure under elevated temperature and moisture conditions. An exact solution is formulated which describes the hygrothermal effects due to heating and moisture diffusion on one surface of a symmetric cross-ply plate made of AS/3501 graphite epoxy with simply-supported boundary conditions.

Isolating Failure Mechanisms In A Fiberglass/Epoxy Tensile Test Specimen Using Acoustic Emission Signal Parameters, Michael Kouvarakos

Master's Theses - Daytona Beach

This study used acoustic emission (AE) signal parameters to isolate the failure mechanisms in a 0° unidirectional, fiberglass/epoxy tensile test specimen. Since several failure mechanisms were known to be present, the lack of any distinctly identifiable bands in the original amplitude distribution indicated that there was considerable overlap between the AE signals of the various failure mechanisms. In order to separate the amplitude bands associated with each mechanism, it was necessary to sort on the duration of the AE signal. Two additional plots, counts versus amplitude and hits versus counts, were used to verify that the amplitude distributions were comprised …

Spectral And Spatial Pattern Recognition In Digital Memory, John M. Amrine

Theses and Dissertations

The main purpose of this research is to develop a model that can be used to solve combined spectral and spatial pattern recognition problems. The basis of my model is a multiobjective discrete programming model developed by Benabdullah and Wright (B and W). The model will be modified and then tested by solving a real world problem with SPOT multispectral imagery. Several improvements were added to the B and W model, namely standard border length accounting and control over which pixels are selected by the model. The model was also improved to process more than one channel of imagery at …

Correlation Based Target Location And Identification, Richard A. Wenzel

Theses and Dissertations

Correlation was investigated as a technique for locating and identifying visible light terrain board images of tanks, airplanes, and trucks. A correlator was built which utilizes the Fast Fourier Transform. The 180 images in the image set were correlated in both the raw form and after pre-processing via energy normalization and local energy normalization. The correlation of the raw images led to development of quantitative and heuristic rules for possible inclusion in a rule based expert system. The correlation of the local energy normalized images resulted in a 100 percent target location rate and can be used as a baseline …

Nonlinear Large Displacement And Moderate Rotational Characteristics Of Composite Beams Incorporating Transverse Shear Strain, Stephen G. Creaghan

Theses and Dissertations

This research was directed toward the investigation of nonlinear large displacements and moderate rotations of composite beam structures considering a finite element potential energy approach incorporating through the thickness shear strain as an analytical function. This approach was compared to large rotation theories. Test cases were run to evaluate numerical algorithms Riks method and displacement imposed techniques were employed. The limitations and advantages of both methods were considered. Loading arrangements included concentrated forces as well as moments.