Engineering Commons^™

Analysis Of Small Airports Within A One Hundred And Twenty Mile Radius Of Medium And/Or Large Airports, Cheryl Mitchell Cunningham

Master's Theses - Daytona Beach

The purpose of this research is to investigate how income, population age, scheduled air carrier services, and distance between competing airports impact annual scheduled passenger enplanements for airports in smaller communities. Small airports located within a 120 miles radius of larger sized (medium or large) airports are considered to be within the "shadow" of larger airports with which they must compete for passenger enplanements.

Two methods were employed to evaluate shadow airports within a 120 mile radius of larger airports. First, an historical view, analyzing each of the airports with regard to schedule passenger enplanements, median disposable incomes, median ages, …

Fracture Mechanics Of High Strength Concrete Members, Rajendra K. Navalurkar

Dissertations

This study investigates the behavior of High Strength Concrete (HSC) under uniaxial state of stresses. Emphasis is placed on experimental evaluation of important mechanical and fracture properties. Owing to high brittleness of HSC, experimental results especially on tensile behavior have been largely limited and scarce. In this research, direct uniaxial tension tests are employed for determination of the post-peak tensile softening characteristics of HSC. The softening characteristics of high strength concrete is found to be considerably different than that of normal strength concrete (NSC). Fracture energies evaluated form the descending branch of the stress softening reveal significant drop in the …

A Controlled Release Technique Using Microporous Membranes, Stephanie Farrell

Dissertations

A novel controlled release device based on aqueous-organic partitioning is described. The device comprises a reservoir, bounded by a microporous or porous membrane in the form of a hollow fiber or flat film. The reservoir liquid phase and the pore liquid phase are immiscible. The agent partitions between the phases at the aqueous-organic interface of the reservoir and the pore mouth, and then diffuses through the membrane pore liquid into a surrounding aqueous solution. The partition coefficient significantly influences the rate of release of the agent by reducing the driving force for diffusion across the fluid-filled membrane pore. The performance …

Vapor-Liquid Phase Equilibria Of Nonideal Fluids With A Ge-Eos Model, Socrates Ioannidis

Dissertations

This study dealt with the prediction and correlation of vapor-liquid equilibria behavior of nonideal fluids. The thermodynamic formalism of the G^E-EoS models, which combines the two traditional methods γ-Φ and Φ-Φ used so far for low and high pressure phase equilibria correlations respectively, has been combined with the 1FG^E model, based on one-fluid theory, to produce a more consistent approach to the phase equilibrium problem.

In the first part of our study we examine the predictive abilities of our model for vapor-liquid equilibria of highly nonideal fluids. The results establish the fact that the Huron-Vidal mixing rule …

Local Stresses On Lateral Pipe-Nozzle With 45 Degree Angle Intersection, James Jin Xu

Dissertations

This dissertation presents a comprehensive study of local stresses, due to internal pressure around a pipe-nozzle with 45 degree angle intersection_ The resulting circumferential and longitudinal stresses on the pipe around the pipe-nozzle region are normalized as local stress factors and plotted as function of beta, β, (the radius of the nozzle/the radius of the pipe) and gamma, y, (the radius of the pipe/the thickness of the pipe) through the finite element method. The range of beta, [3, is from 0.1, to 1.0, and gamma, y, from 10 to 300. Comprehensive studies were made for the boundary parameters, such as …

Motion Estimation And Video Coding, Xiaochun Xia

Dissertations

Over the last ten years. research on the analysis of visual motion has come to play a key role in the fields of data compression for visual communication as well as computer vision. Enormous efforts have been made on the design of various motion estimation algorithms.

One of the fundamental tasks in motion estimation is the accurate measurement of 2-D dense motion fields. For this purpose. we devise and present in this dissertation a multiattribute feedback computational framework. In this framework for each pixel in an image. instead of a single image intensity. multiple image attributes are computed as conservation …

Scheduling And Discrete Event Control Of Flexible Manufacturing Systems Based On Petri Nets, Huanxin Henry Xiong

Dissertations

A flexible manufacturing system (FMS) is a computerized production system that can simultaneously manufacture multiple types of products using various resources such as robots and multi-purpose machines. The central problems associated with design of flexible manufacturing systems are related to process planning, scheduling, coordination control, and monitoring. Many methods exist for scheduling and control of flexible manufacturing systems, although very few methods have addressed the complexity of whole FMS operations. This thesis presents a Petri net based method for deadlock-free scheduling and discrete event control of flexible manufacturing systems. A significant advantage of Petri net based methods is their powerful …

Removal Of Volatile Organic Compounds From Contaminated Groundwater By Pervaporation, Sukla Chandra

Theses

Effective removal of non-aqueous phase liquid pools in groundwater and volatile organic compounds (VOCs) from contaminated soils can be achieved by surfactant flushing. This surfactant-rich ground water contains VOCs like trichloroethylene (TCE), dichloroethylene (DCE), etc. Membrane pervaporation technique is employed here to remove TCE from these micellar systems where a very high percentage of the VOC is trapped inside the micellar core. The micellar solution flows through the bore of microporous hydrophobic hollow fibers wherein the micelles break down and release the surfactants and the TCE. The TCE is then removed through the pores and a nonporous thin silicone skin …

Removal Of Gasoline-Based Hydrocarbons By Vapor Permeation Membranes, Shivashanker Bagavandoss

Theses

Removal and recovery of evaporated lighter gasoline fractions can be effectively implemented by selectively permeating the hydrocarbons (HCs) and other volatile organic compounds (VOCs) from the vented air streams through nonporous hydrophobic polymeric membranes subjected to vacuum on the permeate side and then condensing these organics from the permeate. Such a vapor permeation process employing spiral-wound membranes has already been commercialized for VOCs. In this study, attention has been focused on removal of hydrocarbons from nitrogen flowing through the bore of microporous hydrophobic hollow fibers with a specially engineered nonporous silicone coating on the outside surface with a view to …

The In Vitro Evaluation Of Various Biodegradable Composites Used In Internal Fixation Devices, Hui-Chen Hsieh

Theses

In vitro degradation kinetics and mechanical properties of various composites, comprising a polycarbonate (DTE polymer) reinforced with CaP glass fiber, synthetic ceramic and non-ceramic hydroxyapatite (HA-500,OsteoGen HA) were investigated.

They were soaked in the SBF solution with a constant pH of 7.4 at 37°C for 5 days. The DTE/CaP composite degraded in an acid manner such that a large amount of NaOH was required but with a small decrease in calcium ion concentration. By contrast, the DTE/OsteoGen HA composite required comparable amounts of NaOH, but with a concomitantly large decrease in calcium ion concentration. This showed that the OsteoGen HA …

Relationship Between Precipitation, Surface Runoff, And Shallow Water-Table, Manoj Patel

Theses

In this study, a model was developed to describe the relationship between precipitation, surface runoff, and shallow groundwater table in a watershed that is subjected to groundwater extraction and urbanization. Regression analysis of fourteen years (1976-1989) of time series data for precipitation, stream discharge, ground water elevation, and groundwater extraction yielded good correlation between these parameters.

Analysis of the data associated with groundwater recharge and discharge events that occurred in the watershed from 1976 to 1989 yielded a high correlation between the above cited parameters. Regression analysis utilized to predict monthly variations in groundwater elevations showed a fair correlation between …

Low Pressure Chemical Vapor Deposition Of Silicon Dioxide And Phosphosilicate Glass Thin Films, Vijayalakshmi Venkatesan

Theses

Silicon dioxide thin films were synthesized on silicon and quartz wafers using Ditertiarybutylsilane(DTBS) and oxygen as precursors. Trimethylphosphite (TMP) was injected to obtain phosphosilicate glass. The films were processed at different temperatures between 700°C and 850°C at a constant pressure, and at different flow ratios of the precursors. The films deposited were uniform, amorphous and the composition of the films varied with deposition temperature and precursor flow ratios. The deposition rate increased with increasing temperature and with increasing TMP flow rate. The stresses were very low tensile in the case of undoped silicon dioxide film and tended towards being less …

Real-Time Implementation Of An Adaptive Control System For A 3-Zone Rapid Thermal Processing Station, David Hur

Theses

In this thesis, the implementation details of a real time adaptive control system for a TI 3-zone RTP station, as well as the simulation and the experimental results are presented. Extensive simulation of the system is performed in order to ensure proper operation of the system. The experimental results are used to verify proper operation of the closed loop control system. Initial experiments were conducted using two thermocouples. Further experiments were conducted using one thermocouple for the purpose of testing the performance of the system using Extended Kalman Filter as the state estimator.

The implementation of the control system is …

Biodegradation And Landfill Settlement, Shailesh Pisolkar

Theses

The most widely used method for the final disposal of solid waste is landfilling, which is also economical and simpler than most other disposal systems. Long term settlement in a landfill occurs mainly due to biodegradation of the refuse which is a very slow microbiological process. However, if the rate of biodegradation is enhanced, it may be possible to achieve early stabilization, faster settlement, consequently more capacity of the landfill to handle waste.

The objective of this research is to study the effects of enhanced biodegradation on settlement and to compare these results to other models used for predicting landfill …

Solids Suspension And Power Dissipation In Stirred Tanks Agitated By An Impeller Near The Tank Bottom, Ernesto Uehara-Nagamine

Theses

In this work, the effect of very small impeller clearances off the tank bottom, C, on complete solid off-bottom suspension, Njs, was investigated. Four types of impellers were used six-blade flat-disk turbine, six-blade flat-blade turbine, six-blade flat (45 degreees) pitched-blade turbine, and the high efficiency impeller Chemineer HE-3. The effects of the impeller diameter, D, tank diameter, T, and solids loading, X, were quantified. The presence of two impellers was analyzed using impellers of the same type and size.

Typically, Njs and the power consumption were found to decrease with the impeller clearance. However, for lower C/T values, a slight …

Development Of A Gel Content Analysis Protocol For Ultra High Molecular Weight Polyethylene, Max Harold Jeanty

Theses

A modified procedure based upon ASTM (D 2765 - 90) to determine the gel content of crosslinked polyethylene plastics was developed. The new procedure was applied to ram extruded Ultra High Molecular Weight (UHMWPE) implant components processed under different manufacturing conditions. This new evaluation tool provides consistent results with greater accuracy and consistency compared to the American Society for the Testing of Materials (ASTM) method. Using the same tool, several relationships between the UHMWPE processing conditions and gel content were established. The amount of gel content is related to the crosslinked material. It has been shown that the more crosslinking …

Solidification/Stabilization Of Petroleum Contaminated Soils With Cold Mix Asphalt Concrete, Nazhat Aboobaker

Theses

In this research Petroleum Contaminated Soils (PCSs) are recycled in Cold Mix Asphalt (CMA), to produce a useful product that can control potential environmental threats. The stability, durability, and hydraulic conductivity are three important engineering parameters that need to be considered when using petroleum contaminated soils (PCSs) in cold mix asphalt (CMA). In this research, stability, durability, and hydraulic conductivity due to the addition of six different PCSs into CMA is investigated. The stability test were performed to determine if cold mix asphalt made with petroleum contaminated soil can withstand heavy traffic. The freeze-thaw, and wet-dry tests were performed to …

Fabrication Of Integrated Optic Sensor To Monitor Pollutant Concentration In Effluents, Kiran Chatty

Theses

An attempt has been made to fabricate an integrated optic sensor to monitor pollutant concentration in effluents. Optic fiber has to be coupled to the waveguide in order to send light through the waveguide. In order to facilitate the easy coupling of the fiber to the waveguide, V-grooves were formed in the silicon substrate. In order to achieve this Silicon nitride was deposited to serve as an etch mask. An attempt was made to obtain low stress silicon nitride films.

This work also attempted to synthesize the materials required to fabricate the waveguide. LPCVD processes were developed to produce undoped …

Modeling Of Cardiovascular System To Simulate Ventricular Septal Defect, Adarsh Kumar Gupta

Theses

The hemodynamics of the ventricular septa] defect is studied using a mathematical modeling technique. A twelve-compartment windkessel model of cardiovascular system is used to study the hemodynamics of the ventricular septal defect. The VSD is incorporated into the model via a parallel flow from the left to right ventricles (left-to-right shunt). The resistance to flow through the shunt is used to characterize the severity of the defect. Changes in the severity of the shunt flow produces changes in the ratio of pulmonary to systemic flow in the circulation. When the pulmonary to systemic flow ratio is more than 2:1, the …

Synthesis And Characterization Of Silicon Dioxide Thin Films By Low Pressure Chemical Vapor Deposition Using Ditertiarybutylsilane And Oxygen, Sung-Jun Lee

Theses

This study is focused on the synthesis and characterization of silicon dioxide thin films deposited on silicon wafers by Low Pressure Chemical Vapor Deposition (LPCVD), using ditertiarybutylsilane (DTBS) as a precursor and oxygen as the oxidant. The dependence of film growth rate on various process parameters were studied. The growth rate was found to follow an Arrhenius curve with the variation in the temperature with an activation energy of 12.6 kcal/mol. The growth rate was found to be inversely proportional to the temperature in the range 550-750 °C. The refractive index and density were observed to be close to 1.47 …

Effect Of Lamellar Microstructure On The Permeability Of Polyethylene Films, Yufu Li

Theses

Lamellar microstructures can decrease the permeability to gases and vapors by increasing the diffusive path in plastic films, or the so-called "tortuosity" which depends on the aspect ratio, orientation, and the volume fraction of the dispersed material. In this research, different types and percentages of mica with relatively high aspect ratio are used as oxygen barrier materials in blown films. Both high and low density polyethylenes (HDPE and LDPE), as well as their blends are used as the matrix materials.

A decrease in permeability of both LDPE and HDPE films to oxygen is achieved with increasing volume fraction of the …

Implementation Of Fortran Finite Element Analysis Source Code With Application : Particle Deposition In A 90 Degree Duct Bend, Pantaleo Loiacono

Theses

Two FORTRAN 77 finite element analysis source codes, by 1.N. Reddy, were input into a PC, debugged, executed, and tested successfully. These programs are available to students interested in implementing a good finite element analysis source code on a PC or on a workstation in one or two dimensions. The programs can solve problems relating to heat transfer, stresses, beam analysis, frames, trusses, plane elasticity, plate bending, and laminar viscous incompressible fluids with various node and element combinations.

The two-dimensional program was used to obtain the velocity distributions in a 90 degree duct bend with incoming and exiting fully developed …

Fuel-Rich Combustion Of Ethylene And Air In A Two Stage Turbulent Flow Reactor, Tara Byrnes Salem

Theses

This thesis presents experimental and modeling results from the combustion of ethylene and air in a two stage turbulent flow reactor. This work is motivated by the continuing concern over combustion by-products. The first half of the research effort focused on the validation of the reactor as a perfectly stirred reactor and a plug flow reactor (PSR+PFR) sequence. Using four detailed reaction mechanisms, measured concentrations of carbon oxides, oxygen, and light hydrocarbon concentrations were modeled. Within the accuracy of the data, the mechanism of Mao (1995) yielded the best results. However, it was observed that the success of the reactor …

Residual Stress Analysis Of Sputtered Tantalum Silicide Thin Film, Young Joo Song

Theses

The influence of different argon pressures on the residual stress, microstructure, and resisitivity of sputtered tantalum silicide thin films has been investigated. TaSi₂ films were deposited onto Si wafers by dc magnetron sputtering. The deposition temperature was assumed to be 300°C. The thickness was about 0.5 μm. The residual stresses in the films deposited at different argon pressures were determined by curvature measurement method. The compressive intrinsic stress of 1033.4MPa was measured at P_Ar = 0.5 mTorr. The intrinsic stress in the films seemed to change from compression to tension as P_Ar increased above 8mTorr. A maximum …

Adaptive Color Correlation Of Knots In Wood Images And Weighted-Value Product Selection Methods In A Machine Vision System, John Robert Goulding

Dissertations and Theses

The biggest obstacle to robust color image processing of wood is in developing a color model that represents all possible defect colors. When the color model is too general or too specific, defect recognition fails because too many or too few non-defect pixels match the model, respectively. Because a color image of wood contains far more clear and clear-grain colored pixels than grain-knot and knot colored pixels, it is beneficial to first statistically identify and remove the clear and clear-grain colors and to use the accumulated data to simultaneously enhance and normalize the remaining grainknot and knot colored pixels. This …

Optical Detection Properties Of Silicon-Germanium Quantum Well Structures, Michael R. Gregg

Theses and Dissertations

A study has been carried out on Si/SiGe multi quantum well structures to determine their applicability as normal incidence infrared detectors in the spectral range of 2-12 micrometers. The research effort was primarily experimental; however, extensive calculations were performed to initially explain the experimental data and then used to design subsequent structures. Multiple quantum well structures grown on both Si[001] and Si[110] substrates via molecular beam epitaxy were studied by photoluminescence, absorption, and photoresponse measurements over a wide parameter space. Variables included quantum well depth and width, well doping, number of wells and growth temperature. Well widths were varied from …

Design Of A Second-Order Filter Using The GM-C Technique, Girish Chandrasekaran

Dissertations and Theses

This thesis deals with the design, layout, fabrication, testing and characterization of a second-order filter (biquad) using the transconductance-C (g_m-C) technique. The biquad was designed to realize the four filter functions - lowpass, highpass, bandpass and notch - by appropriate choice of input and output terminals and element values. The tunable range of frequencies for the biquad was designed to be 18-59MHz. The quality factor of the biquad was designed to be tunable from approximately 1/3 to 3. The filter was designed in LEVEL2 SPICE, laid out using MAGIC, and the circuit was fabricated using MOSIS's …

Maximum Likelihood Estimation Of Exponentials In Unknown Colored Noise For Target In Identification Synthetic Aperture Radar Images, Matthew P. Pepin

Theses and Dissertations

This dissertation develops techniques for estimating exponential signals in unknown colored noise. The Maximum Likelihood ML estimators of the exponential parameters are developed. Techniques are developed for one and two dimensional exponentials, for both the deterministic and stochastic ML model. The techniques are applied to Synthetic Aperture Radar SAR data whose point scatterers are modeled as damped exponentials. These estimated scatterer locations exponentials frequencies are potential features for model-based target recognition. The estimators developed in this dissertation may be applied with any parametrically modeled noise having a zero mean and a consistent estimator of the noise covariance matrix. ML techniques …

Study Of Stress In Microelectronic Materials By Photoelasticity, Hancheng Liang

Dissertations

The study of stress is playing an important role in microelectronic technology. In comparison with other techniques, the photoelasticity technique has the advantages of having high spatial resolution and high sensitivity. It can be used in qualitative observation in real-time and quantitative determination of stress distribution in the microelectronic materials and devices.

This dissertation presents a systematic study of photoelastic stress analysis in microelectronic materials and devices, ranged from theoretical study to practical system setup, from measurement methods to their applications. At first, based on the detailed survey on the piezo-optic properties of the crystals used in microelectronics, we apply …

Reaction Kinetics Of Methanol And Mtbe Oxidation And Pyrolysis, Wen-Chiun Ing

Dissertations

This study presents experimental data on the decomposition of methanol in several different reaction environments - fuel lean to stoichiometric at a temperature range of 873 and 1073 K and a pressure range of I and 5 atm. Methane fuel is also added in several of the systems studied in order to provide experimental data to understand the methanol addition effect on the methane oxidation.

Computer codes: ThermCal, ThermSrt and ThermCvt have been developed for the thermal property calculations of stable molecules by the Benson group additivity method and of radicals by the NJIT hydrogen bond increment method.

Pressure dependent …