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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.

An Investigation Of The Combined Heat And Mass Transfer Processes In The Drying Of Hygroscopic Porous Media With Two Disparate Length Scales, Thomas Joseph Phillips

Doctoral Dissertations

A mathematical model describing the drying process in a hygroscopic porous medium with two disparate length scales is formulated. The mathematical model is used to identify the important dimensionless parameters appearing in the problem; and, a parametric study is performed to determine the effects of varying these parameters on the drying process. Of particular interest in this study is to apply the model to the drying of large, round hay bales. Therefore a discussion of how the results of the parametric study impact on the efficient use of a hay drier is also presented.

The results from the parametric study …

The Influence Of Environmental Factors On The Temperature Of The Radiosonde Thermistor, James K. Luers

Doctoral Dissertations

A technique was developed to calculate the radiosonde temperature error as a function of altitude under different environmental conditions. The environmental conditions analyzed include the surface (or cloud) temperature, the atmospheric gaseous constinuents, the aerosol and thermodynamic structure of the atmosphere, the solar elevation angle, the solar albedo, the rise rate of the balloon, and the atmospheric density.

The heat balance equations for the thermistor and lead wires were derived and a sensitivity analysis performed to establish the significance of each heating term. The Air Force LOWTRAN 6 code was used to model the solar and infrared irradiation of the …

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 …

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.

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 …

Thermal Decomposition Of Chlorobenzene Reaction With Hydrogen And Oxygen Mixture In An Atmosphere, Chun-Chen Yang

Theses

The thermal reactions of chlorobenzene in hydrogen and oxygen mixtures were studied in tubular flow reactors at 1 atmosphere total pressure. Experiments were carried out in flow reactors of varied diameter for determining effects of different surface to volume ratios. Residence times ranged from 0.03 to 2.5 seconds and temperature was varied over a range of 560 - 660 °C. The 02/H2 ratios ranged from 1% to 5%.

It was found that the conversion of chlorobenzene in hydrogen and oxygen mixtures increased with both temperature and residence time. The oxidation of chlorobenzene also occurred more rapidly when oxygen concentraction was …

Agitation Requirements For Complete Drawdown Of Floating Solids In Stirred Tanks, Joseph Philemon Mmbaga

Theses

The agitation requirements for complete drawdown of floating solids in mechanically agitated tank vessels has been studied both theoretically and experimentally.

A semi-theoretical equation has been derived on the basis of Kolmogoroff's theory of isotropic turbulence to determine the minimum impeller speed required for drawdown. The equation contains one adjustable parameter which has been found to be a function of the impeller type and position in the tank vessel.

The equation was tested using various vessels and impeller configurations. The solid phase consisted of high density polyethylene (density = 897kg/m³), low density polyethylene (density = 840kg/m³) …

Process Modelling Of The Nitration Of Toluene, Nitin K. Shah

Theses

The thesis on the process modelling of the nitration process focuses specifically on the product separation of the nitrated aromatic material from the reactor and - wash section of the process. Included in the text is an overview of the main process steps associated with the production of para and ortho-nitrotoluene. The critical issues concerning the reaction of nitric acid and toluene were summerized, and resulted in this subject being deferred for future work.

The separation of the isomers into pure components is an important. part of the MNT process because of the close high boiling points of the isomeric …

Protein Separation With Mathematical Modeling For Chromatographic Operation, Hsien-Chih Ma

Dissertations

We have performed experiments and derived mathematical models for packed bed columns used for liquid phase chromatographic separations of proteins with impulse input of feed solutions. These models can now be used to describe the relationships between the elution characteristics (peak height, peak position, and shapes) and the operating conditions (flow rate and buffer conditions) of ion exchange and gel permeation column chromatography for protein separations.

The surface adsorption model was discussed relative to the nature of the mobile and stationary phases in ion exchange column chromatography for two distinct cases: with and without pore diffusion. For large solute molecules, …

Air Stripping Of Volatile Organic Compounds From Groundwater: An Evaluation Of A Centrifugal Vapor-Liquid Contactor, Surinder Paul Singh

Doctoral Dissertations

The performance of a centrifugal vapor-liquid contactor equipped with high specific surface area packing (>2000 m²/m³) was evaluated for air stripping of jet fuel components from groundwater. Hydraulic test data indicated that the Sherwood flooding correlation which has been proposed for use in designing centrifugal vapor-liquid contactors overestimates the rotational speeds at which flooding occurs. For the mass transfer of performance, a concept of area of a transfer unit (ATU) was introduced to account for the change in fluid loading with radius of the packing torus. The ATU was found to be a strong function …

Quantification Of Refining Actions, Hari R. Goyal

Masters Theses

The repeated action of compression-decompression pulses on a wet web of fiber, created by dropping a weight from a height, loosens the internal structure of the fiber. The impaction of fiber did not cause any change in average weighted fiber length, fine content or Canadian Standard Freeness. The sheet made from these fibers showed an increase in tensile strength with increased number of impacts or impact intensity.

In a blend of impacted fibers (internally fibrillated), abraded fibers (externally fibrillated) and fines (fibers shorter than 0.23 mm and created by prolonged beating in a Valley beater), fines were found to be …

An Ergonomic Training Program For Manual Handling Tasks, Akhilesh Agrawal

Masters Theses

The objective of this study was to test whether or not muscular endurance of individuals engaged in industrial manual handling tasks can be improved through a short and intensive training program. This investigation also involved the study of the effect of muscular endurance training program on muscular strength.

The study revealed that, over a six-week period, the muscular endurance can be improved significantly. After sixteen sessions of training, the endurance time increased over 500% for manual materials handling tasks and over 1200% for upper extremity manual handling tasks. The endurance training program, however, did not increase both static and dynamic …

Heat Transfer Model And Computer Program For A Direct-Fired Rotary Kiln, Steven J. Kirslis

Masters Theses

An improved heat transfer model has been developed for a direct-fired rotary kiln. The model can be used to verify Kiln design, to optimize operating conditions, to predict the temperature history of the solids, and to evaluate if local areas of the kiln will be overheated. The treatment of radiant heat transfer was based on the Reflection Method developed by Succec and applied by Gorog, and was extended to account for radiation from a flame. Some elements of the Resistive Network Method and Zone Method were incorporated in the model. This method results in a more straightforward and flexible treatment …

A Comparative Study Of The Performance Of Various Image Analysis Methods For Dimensional Inspection With Vision Systems, Ralf Heinrich Koeppe

Dissertations and Theses

Dimensional inspection with Vision Systems requires a careful selection of image analysis methods in order to obtain accurate information about the geometry of the parts to be measured.

The purpose of this project is to study, implement and compare different image evaluation methods and to show their strengths and weaknesses with respect to dimensional inspection. Emphasis is made on the inspection of circular features. The criteria of comparison for these methods are discussed. Using synthetically generated images, various analysis methods are compared and conclusions for their use are drawn. Results of the comparison show that the selection of a method …

Numerical Study Of Three-Dimensional Separation And Flow Control At A Wing/Body Junction, Balakrishnan Lakshmanan

Mechanical & Aerospace Engineering Theses & Dissertations

The problem of three-dimensional separation and flow control at a wing/body junction has been investigated numerically using a three-dimensional Navier-Stokes code. The numerical code employs an algebraic grid generation technique for generating the grid for unmodified junction and an elliptic grid generation technique for filleted fin junction. The results for laminar flow past a blunt fin/flat plate junction demonstrate that after grid refinement, the computations agree with experiment and reveal a strong dependency of the number of vortices at the junction on Mach number and Reynolds number. The numerical results for pressure distribution, particle paths and limiting streamlines for turbulent …

Superplastic Behaviour And Cavitation Formation Of A1-2li-1.9cu-1.5mg-0.09zr Alloy, Ali Mohamed Farah

Archived Theses and Dissertations

No abstract provided.

Pile Driving Analysis In Selected Egyptian Soil Deposits, Yasser Abd Elhamid Gowayed

Archived Theses and Dissertations

No abstract provided.

Characterization Of Zirconia Gels And Their Selectivity Towards Metal Ions, Manal Mohamed Talaat El- Saidi

Archived Theses and Dissertations

No abstract provided.

Computerized Biomechanical Model Of The Low Back During Lifting And Pushing Activities, Soha Samir Sadek

Archived Theses and Dissertations

No abstract provided.

Biodegradation Of Benzene And A Btx Mixture Using Immobilized Activated Sludge, Mayur Padamshi Lodaya

Dissertations

Aerobic biodegradation of benzene was studied using activated sludge immobilized in calcium alginate (immobilization by entrapment), and also attached to a silica based catalyst.support (immobilization by attachment). Hydrogen peroxide was used as a source of dissolved oxygen to eliminate physical removal of benzene due to aeration. Abiotic losses of benzene were accounted for.

A recirculation reactor, run in both batch and continuous feed mode, was used to determine the kinetic parameters. The system response was examined by tollowing changes in benzene concentration, flow rate, and biomass loading. The system was modeled mathematically and the kinetic parameters were determined.

Biological removal …

Bond And Fatigue Characteristics Of High-Strength Cement-Based Composites, Somboon Chimaphant

Dissertations

The results of a series of tests on a variety of high strength cementitious composites yield a model from which an empirical equation of general normalized pull-out stress vs. pull-out displacement relationship is developed. A new variable named the "Brittleness Index" is defined and used in the proposed equation. Additionally, the concept of maximum strain is used to predict the fatigue life of high strength concrete.

Three sizes of deformed bars and two types of steel fibers with four different volume fractions were used to observe bond-slip and pull-out characteristics of high strength concrete. The results indicate that the maximum …

Kinematic Synthesis Of Mechanisms For Multiply Separated Positions, Hyoung Jun Kim

Dissertations

The rigid body motion is studied in a combination of finitely and infinitesimally separated positions in planar, spherical, and spatial kinematics. A general new method for determining the locations of points and/or lines in a rigid body moving through finitely and infinitesimally separated positions is developed. These points and/or lines would satisfy the constraints of various types of binary links for planar, spherical, and spatial mechanisms.

A unified form of circle-point curve equation is derived for finitely and multiply separated position problems in planar and spherical motions. A graphical method to construct the circle-point and center-point curves and Ball point …

Anaerobic Biodegradation Of Trichloroethylene With The Addition Of Sugar Using Activated Carbon-Fluidized Beds, Suxan Huang

Dissertations

Anaerobic biodegradation of trichloroethylene (TCE) was carried out in a two-stage granular activated carbon fluidized bed bioreactor. The intermediate products were identified as: dichloroethylene (DCE), vinyl chloride (VC), 1,2-dichloroethane (DCA) and chloroethane (CA). Of the three geometric isomers of DCE, the trans-1,2 dichloroethylene (TDCE) was found to be the most predominant species, The production of DCA suggested a diverted reaction sequence from the conventional sequential reductive dechlorination pathway postulated in the past literature. CA was believed to be a product of VC and/or DCA. The co-substrate glucose was implicated for this reaction specificity. Based on our data and on other's …