Engineering Commons^™

An Experimental Study Of The Hydrodynamics Of Multiphase Flow In Fluidized Beds, Gerardo Vargas

Open Access Theses & Dissertations

Fluidized bed reactors have been widely used as a gasifier in coal gasification processes to convert coal into other forms of energy. At this stage, full fluidization is required to attain the best thermochemical reaction within the fluid-solid mixture. This can only be achieved if the fluid is maintained between minimum fluidization and terminal velocities. To better understand the hydrodynamics of multiphase flow, a fluidized bed was designed and constructed to carry out the investigation. Compressed air and 1-mm glass beads were used to determine gas minimum fluidization and terminal velocities at three different particle concentrations. The solids were enclosed …

Treatment Of Ro Concentrate Using Vsep Technology, Guillermo Guadalupe Delgado

Open Access Theses & Dissertations

The city of El Paso has the largest inland brackish desalination plant in the world. The Kay Bailey Hutchison (KBH) Desalting plant produces 15 million of permeate water every day. Due to the excellent quality of the water, the permeate water is blended with brackish water producing a final volume of 27.5 million gallons of water every day. With an average recovery rate of 80%, the KBH plant produces an average of 3 million gallons of concentrated brackish water that is disposed of via injection wells 23 miles from the plant.

Conventional reverse osmosis (RO) systems are not capable of …

Transition Metal Catalysts For Hydrodesulfurization Reactions Applied To Petroleum Industry, Brenda Torres

Open Access Theses & Dissertations

Catalysis plays a fundamental role in petroleum refining and basic petrochemical industries creating new routes in the development of industrial processes. Moreover, catalysis has become indispensable to the solution of environmental pollution problems and therefore on public health. World wide concerns for preservation of the environment has motivated the development of "Green" catalyst based technologies, to achieve a better utilization of petroleum resources and demands for cleaner transportation fuels. These environmental concerns have led to increasingly drastic regulations on sulfur, nitrogen and aromatics content in fuels. Sulfur content in the motor and diesel fuels is continuously reduced by regulations to …

Identification Of Human Gait Using Genetic Algorithm Tuned Fuzzy Logic, Abdallah Abdel-Rahman Hassan Mahmoud

Open Access Theses & Dissertations

Data mining is concerned with the discovery of useful hidden information in large databases. Classification is a data mining task producing rules in which a set of attributes in data predict the value of a class attribute. Classifiers usually produce a large number of rules, most of which are not interesting to the user. Rule interestingness is a decisive factor. However, evaluating rule interestingness is challenging as it involves both objective (data-driven) and subjective (user-driven) aspects.

In this research, a fuzzy genetic algorithm is proposed to discover classification rules that are both accurate and interesting. Continuous attributes are fuzzified so …

Multi-Objective Network Reliability Optimization Using Evolutionary Algorithms, Franciso Oswaldo Aguirre

Open Access Theses & Dissertations

This work presents a new multiple objective evolutionary algorithm to solve three well known network reliability allocation problems considering different conflicting objectives to be optimized simultaneously. The new algorithm is applied in the design of a telecommunication network that is formed for several stations or nodes interconnected by telecommunication links or paths. The problem presented in this work involves finding which links to activate in order to obtain connectivity in the nodes. The number of nodes that need to be connected depends of the case that is being evaluated. The three network reliability problems considered are: all-terminal, k-terminal, and two-terminal. …

Observed Superspin-Glass Behavior In Ni0.5zn0.5fe2o4 Nanoparticles, Antony Adair

Open Access Theses & Dissertations

In this investigation we seek to identify the magnetic behavior of Ni0.5Zn0.5Fe2O4 nanoparticles though AC-susceptibility and DC-magnetization measurements. Powder x-ray diffraction was performed to determine the purity and average diameter ( ~ 9nm) of the particles. Aditionally, structure was confirmed by comparison through the International Centre for Diffraction Data's Powder Diffraction File [52] (PDF # 08-0234).

Zero-field cooled and field cooled DC magnetization measurements (bifurcation and blocking temperature), as well as M(H) hysteresis (below and above the blocking temperature) lead us to initially suggest that the material may in fact be superparamagnetic. However, further investigation of the real AC susceptibility …

Sustainable Development Extension Plan (Sudex): Community Mobilization Through Proactive Participation And Synergistic Alliance To Alliviate Poverty And Achieve Sustainable Self Sufficiency, Stephen Forbes

Open Access Theses & Dissertations

This Dissertation describes a sustainable development extension plan (Sudex Plan) to help communities in developing countries achieve Goal 1 of the United Nation's Millennium Development Goals (MDG). Goal 1 focuses on reducing poverty and hunger by 50% by the year 2015, but all the MDG are interrelated and one can not be achieved without considering the others, and to attain any is an empty accomplishment without ways to ensure that they can be sustained and continuously improved with the means to pass on the information, knowledge and lessons learned from community to community, generation to generation. The Sudex Plan is …

Semi-Automated Frame Transformations Using Fft Analysis On 2-D Images, Francisco Javier Osuna

Open Access Theses & Dissertations

Cassini entered Saturn's orbit on July 1, 2004 beginning a four-year exploration of Saturn. In 2008 the mission was extended, and Cassini continues to collect and transmit images and data collected during its mission. In order to accurately interpret images, it is necessary to know the location and orientation of the camera provided the field of view when the image was collected. While the mission managers provide initial estimates of this orientation, scientific analysis requires better estimates than the initial data provided. Navigation is a process for improving the estimation of the true camera pointing vector as determined by features …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

Using The Taguchi Design And The Central Composite Design To Increase The Robustness Of A Process From Its Raw Material Variability, Alvaro Cuevas

Open Access Theses & Dissertations

This research presents an experimental study where four controllable and one noise factor are analyzed using the Taguchi approach and the Central Composite Design (CCD) in order to induce robustness in a process that is being designed to treat residual grease from small restaurants. Three response variables are analyzed separately to establish the parameters conditions to obtain the most robust process output. These suggested conditions are validated conducting confirmation runs that are compared statistically to the predictions from the Taguchi prediction model for the Taguchi approach, and the Response optimizer for the CCD. The accuracy of each method is measured …

Silica Removal From Brine By Using Ion Exchange, Carlos R. Acevedo

Open Access Theses & Dissertations

Local governments have been forced to look for additional water sources to satisfy the ever increasing demand for fresh water. Very often, the new water sources such as the underground water in continental territories have high salt content. Currently, reverse osmosis technology (RO) is one of the most common processes for water desalination. However, this process is limited by high silica and salt concentrations in water. At high concentrations silica clogs the membranes used in the RO process, reducing their life and increasing operational costs. In this study, quaternary ammonium resins and sulfonic acid resins were used to remove silica …

Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity, Hector Gonzalez-Huizar

Open Access Theses & Dissertations

Seismic waves can trigger earthquakes and tremor at large distances from the causable event. Dynamic triggering occurs when the surface waves from large earthquakes change the stresses conditions on previously overstressed faults, promoting failure. To understand the causative stresses and environments behind dynamic triggering, we model the change in the stress field that the passing of Rayleigh and Love waves cause on a fault plane of arbitrary orientation relative to the direction of propagation of the waves, and apply a Coulomb failure criterion to calculate the potential of these stress changes to trigger seismicity. We apply our model to three …

Estimating Variation In Stiffness And Volume Change Of Clays From Geochemical And Index Properties, Cynthia Roxanna Zuniga

Open Access Theses & Dissertations

Clayey soils from six different locations in Texas were analyzed and evaluated with respect to their expansion and shrinkage and change in stiffness associated with moisture content variation. These soils consist of five high plasticity-index (PI) clays (PI greater than 25) and one low-PI clay (PI = 17). The behavior of the clays changes dramatically with moisture content fluctuation, thus causing stiffness and volume changes throughout the year. Total or differential volume movements caused by swell or shrinkage strains of expansive soils and reduction in modulus can exert enough pressure to damage the pavements and cause maintenance problems.

The intent …

Experimental Study Of The Response Of Semiconductor Detectors For Edxrf Analysis., Sunil Kumar Valaparla

Open Access Theses & Dissertations

This present work relates to the study and characterization of the response function of an energy-dispersive x-ray spectrometer. The problems of energy, efficiency and resolution calibration of the system operating in the energy (5-60 keV) range are discussed. We present the operation characteristics of the portable pyro-electric x-ray generator (COOL-X) and the application of the calibrated response spectrum in the elemental analysis using X-ray Fluorescence (XRF).

We study the response of the Si(Li)-Pin XR-100CR semiconductor detector to low energy photons. The photopeak efficiency was determined experimentally by using radioisotopes and compared against a theoretical efficiency curve. The efficiency for gamma …