Engineering Commons^™

Nanoporous Sio2/Vycor Membranes For Air Separation, Mihir Tungare

Theses

Porous Vycor tubes with 40Å initial pore diameter were modified using low pressure chemical vapor deposition (LPCVD) of silicon dioxide N0₂). Diethylsilane (DES) in conjunction with nitrous oxide (N₂O) was used as a precursor to synthesize these SiO₂ films. The aim of this study was to obtain a considerable selectivity between species of comparable size and hence N₂O was used. The use of N₂O was believed to make the process self-limiting. DES was allowed to flow through the tube and N₂O on the outside in the chamber at 550°C …

Autonomic Activity In Gulf War Veterans Using Heart Rate And Systolic Blood Pressure Variability, Maryann S. Fam

Theses

Heart rate variability (HRV) describes variations of heart rate and is attributed to cyclic fluctuations in autonomic tone. The different methods of heart rate variability analysis allow for a non-invasive assessment of autonomic activity. This study analyzes the heart rate variability through both frequency domain methods and joint time-frequency domain methods which were executed through the LabVJEW graphical programming language. These algorithms were utilized to assess autonomic nervous system activity in Gulf War veterans with no health complaints versus Gulf War veterans with chronic fatigue syndrome. The heart rate variability analysis was obtained from acquired measurements of heart rate and …

Simulation And Analysis Of Wing Rock Physics For A Generic Fighter Model With Three Degrees-Of-Freedom, Ahmed Saad

Theses and Dissertations

Modern fighter designs have been associated with lateral self-excited oscillations own as "Wing Rock". Simulations of wing rock by flow visualization utilities have been encouraged to develop a complete understanding of the fluid mechanism that drives the motion as well as for prediction purposes. Previous wind/water tunnel simulations have been limited to a single degree-of freedom (DoF) in roll. In this study, for the first time, wing rock is computationally simulated in three DoF: roll, sideslip, and vertical motion to study the effect of adding file sideslip and vertical motion. The results are for a generic fighter model consisting of …

A Characteristics Finite Element Algorithm For Computational Open Channel Flow Analysis, Zachariah Chambers

Doctoral Dissertations

For the reliable determination of open channel flows, a minimally dissipative flux jacobian decomposition finite element algorithm is developed for the one- and two-dimensional inviscid open channel flow equation systems. The modifed form of the parent kinetic flux divergence is biased by the characteristic speeds, i.e. eigenvalues of the kinetic flux divergence jacobian, to induce along all wavelike propogation directions a dissipation level proportional to the propogation speeds of the solution to the hyperbolic problem statement.

The analysis rigorously investigates the inviscid open channel equation system via non-linear, wave-like solutions and reveals linear dependency issues for the momentum equations in …

A Delay Model For Exclusive Right-Turn Lanes At Signalized Intersections With Uniform Arrivals And Right Turns On Red, Mohammad A. Qureshi

Doctoral Dissertations

Right turn on red (RTOR) is an established part of today’s driving patterns. However,despite several revisions of the Highway Capacity Manual (HCM), the procedures for estimating delay at signalized intersections do not adequately incorporate the effects of RTOR. The HCM currently removes RTOR from the analysis.

This dissertation has developed models of uniform delay that incorporate RTOR based on queuing theory. Queuing accumulation polygons (QAP) were developed that include RTOR. The research developed a classification system for describing any signal phasing into one of 4 classes based on the sequence of 3 red regimes and one green regime.

It was …

Formulation And Assessment Of A Customizable Procedure For Pavement Distress Index, Zongren Wang

Doctoral Dissertations

A customizable procedure for the formulation of Pavement Distress Index (PDI) based on human rating behavior is presented in this dissertation. This procedure formulates PDI as the maximum PDI value in a user-defined scale minus the Total Deduct Value (TDV), which is the sum of the product of each individual Deduct-Value (DV) and its corresponding weight. These weights, defined as a function of corresponding DV-percentages, i.e. individual DV over TDV, are identified using data simulated according to the studies by Sun and Yao (1991) and PAVER, a Pavement Management System (PMS) developed by the U. S. Army Corps of Engineers. …

An Analysis Of The Influence Of Age And Ionizing Radiation On Cognitive Performance, Elizabeth L. Gerhardt

Master's Theses - Daytona Beach

This thesis was designed to study whether age has a significant effect on cognitive test results among persons exposed to ionizing radiation. The data for this investigation came from the fourth year of a 1995-98 longitudinal study of subjects exposed to radiation from the 1986 Chernobyl, Ukraine, nuclear power plant accident. Accuracy and efficiency scores from four cognitive tests taken by 84 Ukrainian volunteers were divided into two age groups and three radiation dosage groups for analysis. The results of this study found that decrements in human performance on tasks involving spatial processing increase with age in persons who have …

Nonlinear Analysis Of Unsymmetric Laminates Under Cylindrical Bending, Eun Seon Park

Master's Theses - Daytona Beach

Nonlinear analysis of unsymmetric composite long, narrow laminates under cylindrical bending is studied. The nonlinear governing equations are obtained to analyze the cylindrical bending of arbitrary laminates. The von-Karman type geometrical nonlinearity is incorporated in the governing equation. The shear effect between lamina is further considered in the governing equation. The solution is obtained for different boundary conditions. The results of arbitrary angle-plies are discussed. Unidirectional prepreg graphite-epoxy is considered for numerical results.

Analysis Of The Anodic Bonding Process And The Packaging Effects In Mems Devices, Sonya G. Iyasere

Electronic Dissertations and Theses

This paper gives a brief overview of the process of completely sealing and permanently joining glass to a semi-conductor without the use of adhesives known as anodic or electrostatic bonding. It is well known that this process will introduce thermal strain due to different coefficients of thermal expansion between any metal or semiconductor and glass. This paper will also describe the effect of the MEMS packaging process on various devices that are bonded electrostatically.

A Methodology And Sampling System For Monitoring Nonpoint Source Pollution From Land Uses, Bryan Fleet Staley

Masters Theses

Limited research has been done in developing a nonpoint source methodology and monitoring system that enables the quantitative evaluation of land use impacts on water quality in a single watershed. The development of a methodology and sampling system that specifically targets the runoff component of streamflow is important in determining which types of land uses contribute most to water quality degradation. In addition, an established monitoring strategy and sampling system will provide for the collection of water quality data when the pollution potential is greatest.

Both a monitoring methodology and a computer controlled sampling system have been developed that utilize …

An Evaluation Of Relationships Among Streamflow And Selected Water Quality Parameters In A Forested High-Altitude Watershed, Molly Sarah Mccann

Masters Theses

A long-term water quality program has been established at the Noland Divide Watershed (NDW) in the Great Smoky Mountains National Park. The Noland Divide Watershed is a spruce-fir forested catchment which has been shown in previous research to receive some of the largest fluxes of atmospherically-deposited nitrogen and sulfur compounds in the world. Streamwater chemistry data from November 1991 through August 1998 for two streams, the "northeast" (NE) and "southwest" (SW) stream, were examined to note results of this deposition on water quality. Automatic monitoring equipment on both streams measure and record pH, conductivity, and temperature readings every 15 minutes, …

Three-Dimensional Dynamic Stress Analysis Of Sandwich Panels, Victor Y. Perel

Theses and Dissertations

A layerwise geometrically nonlinear theory for a thick sandwich plate was developed by introducing assumptions on a variation of transverse strains in the thickness direction of the faces and the core of the plate. An effect of transverse extensibility or compressibility of the core and the face sheets is taken into account, and the terms associated with transverse shear strain of the face sheets and the core are included into the expression for the strain energy. Displacements, obtained by integration of the strain-displacement relations, depend nonlinearly on a coordinate in the thickness direction, and are continuous at the boundaries between …

Numerical Simulation Of Acoustic Wave In A Convergent-Divergent Nozzle Using A Characeristic Based Algorithm, Haitham Maher Mahmoud

Archived Theses and Dissertations

No abstract provided.

An Investigation Of Skill Acquisition Under Conditions Of Augmented Reality, Russell P. Milham

Master's Theses - Daytona Beach

Augmented reality is a virtual environment that integrates rendered content with the experience of the real world. There is evidence suggesting that augmented reality provides for important spatial constancy of objects relative to the real world coordinate system and that this quality contributes to rapid skill acquisition. The qualities of simulation, through the use of augmented reality, may be incorporated into actual job activities to produce a condition of "just-in-time learning." This may make possible the rapid acquisition of information and reliable completion of novel or infrequently performed tasks by individuals possessing a basic skill-set. The purpose of this research …

Fluid Flow In Micro-Channels: A Stochastic Approach, Hilda Marino Black

Doctoral Dissertations

In this study free molecular flow in a micro-channel was modeled using a stochastic approach, namely the Kolmogorov forward equation in three dimensions. Model equations were discretized using Central Difference and Backward Difference methods and solved using the Jacobi method. Parameters were used that reflect the characteristic geometry of experimental work performed at the Louisiana Tech University Institute for Micromanufacturing.

The solution to the model equations provided the probability density function of the distance traveled by a particle in the micro-channel. From this distribution we obtained the distribution of the residence time of a particle in the micro-channel. Knowledge of …

Environmental Evaluation Of Incinerators In Egypt & Waste Management Of Ash, Aya Mohamed Lamei

Archived Theses and Dissertations

No abstract provided.

Design Of Adaptive Sliding Mode Fuzzy Control For Robot Manipulator Based On Extended Kalman Filter, Abdelrahman Aledhaibi

Mechanical & Aerospace Engineering Theses & Dissertations

In this work, a new adaptive motion control scheme for robust performance control of robot manipulators is presented. The proposed scheme is designed by combining the fuzzy logic control with the sliding mode control based on extended Kalman filter. Fuzzy logic controllers have been used successfully in many applications and were shown to be superior to the classical controllers for some nonlinear systems. Sliding mode control is a powerful approach for controlling nonlinear and uncertain systems. It is a robust control method and can be applied in the presence of model uncertainties and parameter disturbances, provided that the bounds of …

Signal Modeling With Non-Uniform Time Sampling Of Features For Automatic Speech Recognition, Montri Karnjanadecha

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents an investigation of non-uniform time sampling methods for spectral/temporal feature extraction in speech. Frame-based features were computed based on an encoding of the global spectral shape using a Discrete Cosine Transform. In most current “standard” methods, trajectory (dynamic) features are determined from frame-based parameters using a fixed time sampling, i.e., fixed block length and fixed block spacing. In this research, new methods are proposed and investigated in which block length and/or block spacing are variable. The idea was initially tested with HMM-based isolated word recognition, and a significant performance improvement resulted when a variable block length and …

Advanced Atmospheric Water Vapor Dial Detection System, Tamer Refaat

Electrical & Computer Engineering Theses & Dissertations

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface.

This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto …

Validation Of Passive Air Sampling Monitors Onboard United States Navy Submarines, Larry A. Mcfarland

Community & Environmental Health Theses & Dissertations

An operating submarine creates a unique air quality mixture of compounds that result from a combination of human metabolism, construction materials, materials brought onboard and compounds created through the interaction of ship systems. A comprehensive study of submarine atmospheres is ongoing during deployments of U.S. Navy nuclear submarines. As part of the overall effort, a paired air sampling comparison field validation was conducted to compare the air sampling effectiveness of passive diffusive monitors compared to more traditional active air sampling methods when sampling for acrolein, formaldehyde and ozone in the enclosed submarine atmosphere. Acrolein monitors containing 2-hydroxymethylpiperidine (HMP) impregnated glass …

Resolution Of Overlapping Spectra By Wavelength Modulation Spectroscopy, Audra Michiele Bullock

Electrical & Computer Engineering Theses & Dissertations

Wavelength modulation absorption spectroscopy is a highly sensitive, non-intrusive technique for probing gaseous species, which employs the well-known principles of modulation spectroscopy in a novel way. With this technique, parameters such as velocity, density, and temperature can be measured with a high degree of precision. The research presented here shows that wavelength modulation is a convenient means of increasing the sensitivity of an absorption spectroscopy measurement because it allows for harmonic detection. The focus of the dissertation is resolution of overlapping spectra by harmonic detection and the advantages gained by performing detection at the higher harmonics, e.g., sixth and eighth. …

Cfmms – Computerized Facilities Maintenance Management System, Prawit Rotsawatsuk

Masters Theses

Computerized facilities maintenance management systems, previously available only to very large facilities, are now accessible to small and medium-sized maintenance organizations. Advertisements for such products promise reductions in maintenance costs. Where a manual system of maintenance management is currently employed, moderate reductions in maintenance costs and facility downtime are fully possible. Where no formal maintenance management procedures are present, the structure and case of a computerized maintenance system can result in dramatic cost reductions and improvements in facility availability. There are, however, practical limits to the applicability of computerized maintenance systems. The objective of any maintenance program is to minimize …

The Development Of A Fmea Process For Design And Maintenance, Tearesa Lynn Wegscheid

Masters Theses

Failure Modes and Effects Analysis (FMEA) is a systematic way to identify and evaluate potential product and process related failure modes, the associated causes of failures, and the necessary actions to eliminate or reduce the chance of the failure. There are a number of published manuals and books on FMEA. The materials provide a definition of the FMEA form and examples of the Design and Process FMEA. However, there are many inconsistencies throughout the literature. As a result, FMEA is not always value-added.

The thesis is twofold. First, it documents a case study that uses Design FMEA extensively. The case …

Identification Of Risks In Construction Contracts, Hala Mohamed Fouad Afify

Archived Theses and Dissertations

No abstract provided.

A New Hierarchical Negotiation Scheme On Top Of Interrap-Like Multi-Agent Architecture, Nehal Abd Elaziz Hammouda

Archived Theses and Dissertations

No abstract provided.

Image Compression Of Facial Photographs Based On Btc/Tsvq Local Processing, Suhair Hafez Najib Amer

Archived Theses and Dissertations

No abstract provided.

Turbo Codes For Wireless Mobile Communication Systems Applications, Moataz M. Salah

Theses and Dissertations

Research in coding theory has seen many proposals aimed at the construction of powerful codes using block and convolutional codes. Recently, a new forward error control code, known as turbo code, was introduced. This new code yields very good performance (near the Shannon limit) with relatively simple component codes and large interleavers in combination with an iterative decoding process. Among the most important applications of turbo codes are wireless mobile communication systems. A significant performance metric for this application is the minimization of end-to-end delay. In this dissertation, different ways to enhance the performance of turbo codes with short frames …

Swarm Engineering, S. Kazadi '90

Doctoral Dissertations

Swarm engineering is the natural evolution of the use of swarm-based techniques in the accomplishment of high level tasks using a number of simple robots. In this approach, one seeks not to generate a class of behaviors designed to accomplish a given global goal, as is the approach typically found in mainstream robotics. Once the class of behaviors has been understood and decided upon, specific behaviors designed to accomplish this goal may be generated that will complete the desired task without any concern about whether or not the final goal will actually be completed. As long as the generated behaviors …

Intermodal Transit System Coordination With Dynamic Vehicle Dispatching, Md. Shoaib Chowdhury

Dissertations

In most urban areas where transit demand is spread widely, passengers may be served by an intermodal transit system, consisting of a rail transit line (or a bus rapid transit route) and a numbers of feeder routes connecting at different transfer stations. In such a system, passengers may need one or more transfers to complete their journey. Therefore, scheduling vehicles operating in the system with special attention to reduce transfer time can contribute significantly service quality improvements. In this study two models, one for coordination of a general intermodal. transit system and another for dynamic dispatching of vehicles on coordinated …

Multimedia Modeling Of Organic Contaminants In The Passaic River Watershed, Lansana Coulibaly

Dissertations

A dynamic fate and transport multimedia environmental model was developed and applied to assess the release of five priority contaminants in the Passaic River Watershed, including: napthalene, toluene, trichloroethylene, 1-1-1 trichloroethane and xylene. The model uses the current releases of contaminants as well as cross-boundary advection to determine the fate and environmental distribution of these chemicals in the watershed. The model was developed using a dynamic fugacity approach in order to allow for scenario analysis such as source reductions and no-action alternatives. This modeling effort is expected to achieve a comprehensive assessment of contaminants not only in the proximity of …