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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 …

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, …

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 …