Engineering Commons^™

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 …

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, …

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 …

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 …

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, …

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 …

Fault-Tolerant Interconnection Networks For Multiprocessor Systems, Hamed Mohamed Nassar

Dissertations

Interconnection networks represent the backbone of multiprocessor systems. A failure in the network, therefore, could seriously degrade the system performance. For this reason, fault tolerance has been regarded as a major consideration in interconnection network design. This thesis presents two novel techniques to provide fault tolerance capabilities to three major networks: the Baseline network, the Benes network and the Clos network.

First, the Simple Fault Tolerance Technique (SFT) is presented. The SFT technique is in fact the result of merging two widely known interconnection mechanisms: a normal interconnection network and a shared bus. This technique is most suitable for networks …

Air Stripping Of Volatile Organic Contaminants Using Rotating Disc Contactor, Kai-Ping Hsueh

Dissertations

Previous studies have suggested that the transfer of VOCs to the atmosphere by air stripping may be a convenient and potentially cost-effective method to remove these compounds from the water. A Rotating Disk Contactor (RDC), similarly to other aeration devices, can provide intimate contact between the VOC-bearing water and air. It is believed that under carefully selected operating conditions, the RDC system are more competitive with packed tower than other aeration methods. The objectives of this study were to evaluate the feasibility of using the RDC to strip VOCs from the contaminated water and to develop a mathematical model to …

Close-Range, Noncontact Distance Measurement By Controlled Image Irradiance, Jaeho Kim

Dissertations

Dimensional measurement or check is a major part of the inspection and quality control in manufacturing. Most of the measurement applications are based on contact methods. While a number of non-contact methods are available, they are limited in accuracy, in flexibility, or in the range of application areas. An optical, close-range, non-contact distance measurement method has been developed for manufacturing and other applications. Based on a simple imaging principle, the method derives the distance information from the power response of a small axial image area, the irradiance of which is controlled by an active controlled illumination of the corresponding object …

Isoparametric Finite Elements For Linear Isotropic Micropolar Plate Bending, Vallanore K. Suresh

Dissertations

Finite element analysis programs for bending of linear isotropic micropolar elasticity are developed in this thesis. Isoparametric two-dimensional and three-dimensional elements are used to solve plate bending problems. Two-dimensional and three-dimensional finite element formulations are developed. Corresponding finite element programs are then developed. Patch tests are performed on the two-dimensional elements. Convergence studies are undertaken for the elements. Several plates are considered to evaluate the finite element scheme. The effects of the coupling factor N and characteristic length 1 are studied. A post processor with graphical display of displacements is developed.

Numerical results obtained for various plates are in good …

Permeability And Volume Change Characeristics Of Bentonite-Sand Mixes In A Contaminant Environment, Yuan-Hsun Wu

Dissertations

This research was conducted to study the characteristics of permeability and volume change of bentonite-sand mixes due to contaminants. The soil specimens consisted of clean sand, bentonite, and fly ash. Test liquids included seven diluted organic and inorganic chemicals and a landfill leachate.

Index tests included liquid limit, expansion, cracking, and sedimentation tests. Expansion tests proved to be the most useful for permeability evaluation in a contaminant environment.

The conventional consolidometer permeameter and flexible wall permeameter proved to be not completely satisfactory for testing soft bentonite mixes. A triple ring permeameter was developed to compensate for the limitations of these …

Thermotropic Liquid Crystalline Polyesters Based On The Monomer Of Poly(Ethylene Terephthalate), Satish Baliga

Dissertations

A series of thermotropic liquid crystalline polyesters were synthesized, based on Bis-hydroxyethyl terephthalate (BHET), para-acetoxybenzoic acid (PAB) and terephthalic acid (TA). Structural studies of these aromatic polyesters using Nuclear Magnetic Resonance (NMR), Infrared Spectroscopy (IR) and X-ray diffraction techniques indicated the existence of substantial amounts of rigid -PAB-PAB- linkages within the mesogenic backbone. Optical study of their melts using Polarizing Microscopy indicated a "threaded" microstructure typical of a nematic mesophase. Morphological rearrangements were found to occur at higher temperatures as was evident from a two-phase structure, one phase speculated to be rich in flexible Poly(ethylene Terephthalate) (PET) segments and the …

Kinetic Study On Pyrolysis Of C6h5cl And M-C6h4cl2 Diluted In H2 : Detailed Reaction Kinetics And Thermodynamic Property Estimation Techniques, Edward Robert Ritter

Dissertations

Thermal reaction studies of dilute mixtures (0.37%) of C6H5Cl in hydrogen and m-C6H4C12 (0.4%) in hydrogen have been performed in tubular flow reactors at various surface to volume ratios, and 1 atm total pressure. Residence times range from 0.02 to 2.5 seconds,with temperatures between 1050 to 1275 K. HCl, C₆H₅Cl, C₆H₆, and carbon solids (C(s)) are observed as the major products; minor products include methane, cyclopentadiene, toluene, naphthalene and biphenyls. Pyrolysis in helium yields significantly less conversion, but more C(s) for similar residence times.

A detailed chemical mechanism is developed to describe …

Competitive Bidding Strategy In The Construction Industry : A Game Theoretic Approach, Hongbin Chen

Theses

A game theoretic approach is applied to analyze competitive bidding in the construction industry because previous models do not consider the conflict of interest that exists among competitors. The game theoretic model improves corporate performance when compared to previous Bayesian analyses.

The game theoretic model is discussed in conjunction with construction contracting practice. Competitive bidding is formulated as a game theoretic model in which a contractor optimizes his bid price to maximize his utility or corporate performance. Using available historical data, order statistics are employed to access the distribution of estimated costs among bidders for a project. The winner's curse …

A Study Of The Effect Of Some Inhibitors On The Corrosion Rates Of Austenitic Stainless Steels In Sulfuric Acid, Shang-Yinn Chiou

Theses

Four sulfur-containing and three nitrogen-containing organic compounds have been tested as inhibitors for four different austenitic stainless steels-SS304, S5316, SS317L, and SS41O-in 10-50 weight% sulfuric acid solutions respectively. Results confirmed that the sulfur-containing compounds were more effective than the nitrogen-containing compounds. The effect of sodium iodide additions on the behaviours of two of the nitrogen-containing compounds was also studied. The synergistic effect caused by the 1 ion was essential for nitrogen-containing compounds as inhibitors in sulfuric acid solution.

Integrated Voice/Data Services On Multihop Radio Networks, Chialun Lu

Theses

Integrated voice/data is the first step toward Integrated Services Digital Networks (ISDN). Various techniques have been proposed and analyzed for multiplexing voice and data over a large bandwidth channel. Network efficiency is what we are most concerned about. In this paper, we address the problem of determining optimal access policies for a tandem ISDN network by using Dynamic Programming. Computer simulation shows that optimal policy minimizes the data delay.

Statistical Multiplexing Of Video Sources For Packet Switching Networks, Krishna Kancherla

Theses

Communication networks are fast evolving towards truly integrated networks handling all types of traffic. They employ integrated switching technologies for voice. video and data. Statistical or asynchronous time division multiplexing of full motion video sources is an initial step towards packetized video networks. The main goal is to utilize the common communication channel efficiently, without loosing quality at the receiver. This work discusses the concept of using statistical multiplexing for packet video communications. The topology of a single internal packet network to support ISDN services has been adopted. Simulations have been carried out to demonstrate the statistical smoothing effect of …

Rays And Beams Near The Shadow Boundary, Weixing Gao

Theses

Asymptotic techniques in wave propagation problems exhibit attractive features in computational aspects compared to numerical methods. However, they experience problems in complicated environments due to the transition regions associated with them. The transition region involving a shadow boundary in the downward refractive index profile has been investigated. The ray paths were determined solving the ray equation analytically. The Green's function due to a line source is constructed and evaluated using numerical integration (reference solution) and asymptotic techniques. Then, the field produced by the source, is synthesized, using superposition of beams generated from complex source point representation. The floating parameters such …

Reduced Complexity Receivers For Trellis Coded Modulations Via Punctured Trellis Codes, Bonchul Koo

Theses

We introduce a new concept, called matched punctured trellis encoding, that simplifies the complexity of Maximum Likelihood Sequence Estimation (MLSE) receivers for combined trellis encoding and modulations with memory. Matched punctured trellis encoding is applied to tamed frequency modulation (TFM) which is a bandwidth efficient correlative - FM scheme. TFM finds applications in satellite, microwave radio, and mobile communications.

Our approach is based on puncturing a rate - 1/2 matched convolutional code to obtain a rate - 2/3 mismatched code. A matched code is one that produces trellis coded modulations of minimum complexity. Puncturing these codes to obtain mismatched codes …

Schottky-Barrier Solar Cells, Surface Patterning For Efficient Light Collection, Constantinos Manolis

Theses

Different geometrical surface configurations are considered here for a Au/n-Si semiconductor Schottky-barrier solar cell to improve their light collection efficiency.

Optical and electrical properties are theoretically analyzed for two given optical wavelengths of 0.9 and 0.5 micrometers respectively.

The configurations considered are: V-shaped, Star- shaped, M-shaped, asymmetric-V-shaped, and asymmetric-M-shaped. They all show a significant improvement in the short-circuit current over a flat cell model, while the open-circuit voltage remains practically unchanged.

Design Of A Gear Driven Anti-Twister Mechanism For A Seal-Less Blood Processor, Ajit Nachiket Dastane

Theses

This thesis presents the design of a gear driven anti- twister mechanism for a blood cell separator. The anti- twister mechanism allows for continuous feed and discharge lines that are rigidly attached to the rotating centrifuge head, thus eliminating the need of rotating seals. It is anticipated that the device using a gear driven anti-twister mechanism will have smoother power transmission and closer rpm tolerances.

In addition, a procedure for the dynamic analysis of the existing device, which uses a belt-driven anti-twister mechanism, is developed. The experimental values obtained from the device are compared with the theoretical values obtained by …

Recirculation Flow Bioreactor For The Synthesis Of Nitroxide And N-Oxide Pharmaceuticals, Douglas Lischick

Theses

An investigation of the properties of calcium alginate immobilized hog liver microsomes, rich in FAD-containing mixed function oxidase, was performed. Studies involving catalyst storage, immobilization of cofactors within the matrix, and alginate gel concentration were performed using a 1.8 ml mixed flow micro assay reactor. A recirculation flow reactor was designed and used for the biochemical production of 2,2,4,4-tetramethyl-1,3-oxazolidine-l-oxyl, a potentially useful MRI contrast agent.

The activity of the immobilized microsomes was found to increase over time when stored in CaCl₂ or in buffer at 4-8°C. The increase in activity is a result of the removal of inherent inhibitors …

Computer Controlled Oxygen Bioreactor, Dinesh Sachdeva

Theses

A computer controlled oxygen bioreactor has been designed to obtain more accurate values for oxygen bioreactor requirements and to optimize oxygen productivity with respect to oxygen concentration. This study solves a specific problem relating to oxygen concentration measurement and bioreactor control. The proposed reactor system is computer controlled to insure a desired oxygen concentration supply to an oxygen consuming reaction or organism. This thesis also explains and illustrates the bioreactor and its computer control system.

The computer controller incorporates oxygen sensing, oxygen measurement and temperature measurement, Electrical circuits have been designed and built for proper signal conditioning, data acquisition, data …

Ph Parametric Pumping : An Examination Of Different Feed Locations For A Two And Three Column Process With The Same Flow Patterns And Ph Distribution, Roberta Rosty

Theses

PH parametric pumping is used to separate protein mixtures of hemoglobin and Albumin.

In this thesis, modifications to a two-column process, where the fluid stage flow pattern and the pH distributions were constant, were explored. These modifications consisted of: changes in the feed stream inlet and outlet locations, changes in the amount of feed itself, and an addition of another column and reservoir to the original two-column process. The results were obtained through computer simulation.

Results indicate that the batch or no-feed two and three column processes yield better separations of the two proteins than the same processes with feed …

Prediction And Correlation Of Liquid-Liquid Equilibria, Jose Simonetty Jr.

Theses

The NRTL, LEMF, and UNIQUAC models are used in the prediction and correlation of liquid-liquid equilibrium data for ten type I systems. The results indicate that best predictions are obtained with the LEMF equation, with an overall average absolute percentage error in distribution coefficients of 19.5 as compared to 23.0 and 24.7 with the NRTL and UNIQUAC equations, respectively. Good correlation of liquid-liquid equilibrium data alone is obtained with all three models; the LEMF equation is slightly better with an overall average absolute percentage error in distribution coefficients of 5.5 as compared to 6.7 and 5.9 for the NRTL and …

Application Of Microwave Energy To Remediation Of Soils Contaminated With Chromium, Chih-Ju Jou

Theses

A process based upon microwave treatment has been developed to render soil non-hazardous after that soil had been classified as hazardous due to heavy metal contamination. It has been applied to chromium-contaminated soil. The object of the present regulations is to prevent damage to water supplies as a result of the leaching of heavy metal ions from the soils. This object is expressed in the standard test for leaching, namely, the EPA EP Leachate test. This process can be used to immobilize metal ions sufficiently to meet the aforementioned standard. The present standard is based upon acid leaching, and not …