Physical Sciences and Mathematics Commons^™

Synthesis And Characterization Of Acetylenic Derivatives Of The Actinide Extractant (Aryl) N,N Di (Alkyl)Carbamoylmethylphosphine Oxide (Cmpo), Mario Ivan Baeza

Open Access Theses & Dissertations

We have used the reaction between the sodium salt of (diaryl)-N,N-di-(isobutyl)carbamoylmethylphosphine oxides {[Aryl)2P=O][iBu2NC=O]CH}-Na+ and chloromethylacetylenes to produce the first acetylenic derivatives of the carbamoylmethylphosphine oxide (CMPO) actinide extractants. The new compounds - CMPO-CH2C2H (1) {aryl = phenyl}, (2) {aryl = tBu-phenyl}; CMPO-CH2C2Me (3) {aryl = phenyl}; and CMPO-CH2C2CH2Cl (4) {aryl = phenyl}, (5) {aryl = tBu-phenyl} - have been characterized by spectroscopy (1H, 13C, 32P NMR) and also by single crystal X-ray diffraction. These new extractants lead the way to new derivatives aimed at using the materials as both optical and electrochemical actinide and other metal sensors.

Exponential Dichotomy Of Ode's, Nada Farid Al-Hanna

Open Access Theses & Dissertations

I present an elementary Functional Analytic proof of the roughness of Exponential Dichotomy of Ordinary Differential Equations (with exponential growth) on an arbitrary Banach Space.

Magnitude Of Right-Lateral Offset On The Southern Death Valley Fault Zone From Miocene Volcanic Assemblages, Sabrina Michelle Canalda

Open Access Theses & Dissertations

In this study correlation of Miocene volcanic and sedimentary rocks in southern Death Valley is used to constrain the total amount of slip on the southern Death Valley fault. The tertiary volcanic section near Ibex Pass is correlated to rocks ~35 km to the northwest, in the Wingate Wash region (Luckow et al., 2005). Geochronology by Luckow et al. (2005) in Wingate Wash and the Owlshead Mountains has the region divided into two basic periods: an early interval (~14-13.4Ma), and a later phase (~13-12.5Ma). One date from the volcanic sequence in Ibex Pass has been reported (Calzia, 2000) suggesting that …

Lipid Metal Organic Networks, Maria Eugenia Martinez

Open Access Theses & Dissertations

Metal–organic frameworks (MOFs) first appeared in the literature in 1991 and consist of three dimensional structures constructed by linking transition metal ions together through highly directional bonding with organic ligands. MOF materials offer the ability to choose from variety of metal centers that allow the tailoring of optical or magnetic properties, as well as control, to some extent, the size of the coordination sphere. Another advantage is the numerous organic ligands form which suitable pore geometries may be constructed with customized functionality among many applications in other areas such a gas storage chemical separations and selective catalysis. The primary objective …

High-Temperature Phase Transitions In Rbh2po4, Heber Jair Martinez

Open Access Theses & Dissertations

Recent studies have shown that the proton conductivity of MH2PO4 (M=Cs, Rb) solid-acids exhibits a sharp, several-order-of-magnitude increase upon heating above a certain temperature threshold [Boysen et al., Chem. Mater. 15, 727(2003), Boysen et al., Chem. Mater. 16, 693(2004)]. This so-called superprotonic behavior allows the above-mentioned compounds to function as fuel-cell electrolytes at intermediate temperatures [Boysen et al., Science 303, 68(2004)], a remarkable application that has attracted much interest. Yet, the crystal structures and microscopic mechanisms responsible for this heating-induced proton conductivity enhancement are not fully understood.

Our group has previously demonstrated [Botez et al., J. Chem. Phys. 127, 194701(2007)] …

The Isotopological Homodesmotic Reaction: A Further Refinement To The Quantification Of Aromaticity, Marco Olguin

Open Access Theses & Dissertations

Aromaticity imparts a significant energetic stabilization to various chemical systems as a result of cyclic pi-electron delocalization. One of the most widely used methods for the quantification of the Aromatic Stabilization Energy (ASE) of a molecule is the formulation of a Homodesmotic reaction. The following research employs a refined Homodesmotic approach based on previous work by Herndon and Mills which utilized Isotopological Homodesmotic Reactions (IHR) to determine the Aromatic Stabilization Energy (ASE) of a flourenyl cation. The advantage of employing an IHR for an ASE calculation is that the strain energy contribution from the sigma framework of reactant and product …

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 …

Synthesis And Characterization Of Organic-Inorganic Colorants, Kiran A V Adiraju

Open Access Theses & Dissertations

New colorant materials have been found with the interaction of organic dyes and metal alkoxides. Changes in the hue are observed as indigo dye or thioindigo dyes are combined with the ASB (aluminum tri-secbutoxide), when compared to the original indigo or thioindigo dye, due to the binding and geometry change between dye and metal alkoxide. These dyes are combined with the ASB in two different methods of hydrolysis, namely in the air and in water. Similarly, when TTIP (Titanium tetraisopropoxide) is hydrolyzed using the sol gel process, along with the incorporation of thioindigo dye, hue changes were observed. X-ray diffraction …

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 …

Toxicity Of Zinc Oxide And Cerium Oxide Nanoparticles To Mesquite, Jose Angel Hernandez Viezcas

Open Access Theses & Dissertations

The impact of metal nanoparticles (NPs) in biological systems is still not well understood. Little is known about the response of plants, the first trophic level, to NP exposure; consequently, their possible role on the fate and transport of NPs in ecosystems is unknown. The aim of this research was to determine the response of mesquite (Prosopis juliflora-velutina), a native desert plant, to ZnO and CeO2 (nanoceria) NPs. Mesquite seedlings were grown for 15 days in hydroponics with of ZnO (10 nm) and CeO2 NPs (10 nm) at concentrations varying from 500 to 4000 mg L-1. In the present study, …

Geography Of Pestecide Exposure In The Lower Valley (El Paso County, Texas), Critina Solis Sanchez

Open Access Theses & Dissertations

Previous studies using GIS have been used to understand the demographics of particular areas of a city and the risks associated with living there. In the Lower Valley (Socorro, Clint, and San Elizario) area of El Paso County (TX), there has been a rapid growth in population. This increase in growth has led to this project about the types of pesticides used in farms and if they are creating possible health risks for people living in this area and which populations are most at risk. To determine population risk, I use existing GIS information, specifically a USDA aerial photograph taken …

Resistivity And Conductivity Studies Of The Rattlesnake Springs, New Mexico Watershed, Claudia Santiago

Open Access Theses & Dissertations

Rattlesnake Springs are a high-discharge artesian springs situated in the upper Black River Valley in southwestern Eddy Country, New Mexico. The aquifer that supplies the Rat- tlesnake Springs has been the main water source for domestic use by visitors of Carlsbad Caverns National Park and residents of neighboring ranches since the 1930s. Several ge- ological studies relying on surface geology and limited water wells had previously been conducted in the area to examine the trend of ground water flow. In this study I used con- ductivity and resistivity geophysical techniques to identify possible locations of fractures in the subsurface of …

Survey Research On Communication And Language For English Language Learners And Native English Speakers Enrolled In A College Course On Statistical Literacy, Maria Guadalupe Valenzuela

Open Access Theses & Dissertations

The purpose of this study was to examine in what ways language is a factor that affects the learning process of students in an introductory statistics class. This research used a questionnaire survey instrument called: CLASS, Communication, Language And Statistics Survey that was applied to a total of 137 college students from a large southwestern public university, 83 of these students were self-identified as native English speakers (NOELL) and 53 were self-identified as English learner speakers (ELL) and one was dropped. This research found that in statistical instruction, there are some particular differences in behavior and learning process in the …

The Problem Of Time In Quantum Mechanics, Crisol J. Escobedo

Open Access Theses & Dissertations

The purpose of my Thesis is to gain a better understanding of the nature of time and the problems associated with time. For example, I aim to explore the problem associated with the energy-time uncertainty relation due to the lack of a universal operator for time. Using Jan Hilgevoord's work, I will explore the idea that if a measure of time is to be obtained in quantum mechanics, then time has to be a property of physical systems that can only be measured in relation to other systems. As such, time cannot be independent of physical systems. This implies that …

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 …

Improving Throughput Of Simultaneous Multithreaded (Smt) Processors Using Shareable Resource Signatures And Hardware Thread Priorities, Mitesh Ramesh Meswani

Open Access Theses & Dissertations

Simultaneous multithreading (SMT) allows multiple hardware threads to execute concurrently on a processor core, potentially increasing the utilization and throughput of the processor core by a factor of the degree of multithreading. However, such performance gains may not be achieved due to contention for resources shared by the threads. Hardware thread priorities can be used to control the ratio of decode cycles allocated to the hardware threads of a processor core and, therefore, the degree of resource contention among the threads. The IBM POWER5, which has two hardware threads associated with each of its two cores, supports hardware thread priorities. …

Earth Field Magnetic Resonance Imaging And Paramagnetic Contrast Agents, Saideh Sadat Mortazavi

Open Access Theses & Dissertations

The goal of this research was to visualize the uptake of copper by plants to aid phyto-remediation research. The hypothesis was that regions of the plant with more copper will have an enhanced NMR signal using copper as a paramagnetic contrast agent.

As the name implies, Earth Field Magnetic Resonance Imaging (EFMRI) spectrometry uses a magnetic field 300,000 times weaker than a 600 MHz Nuclear Magnetic Resonance (NMR) spectrometer. Just like in conventional human MRI, this portable instrument is capable of recording one, two and three dimensional images though the sample size is much smaller.

The enhancement of signal was …

Salt Separation Processes In Salt Cedar, Rudy Sookbirsingh

Open Access Theses & Dissertations

Salt cedar (genus Tamarix, Family Tamaricaceae) is an exotic, invasive plant in southwestern North America; it has a poor reputation as a heavy-consumer of water and a threat to the landscape and ecology of the region. This study focuses upon saltseparation mechanisms in the salt cedar species Tamarix ramossissima (Ledeb.) which were investigated with a variety of microscopic techniques. The results indicate that this species can produce different salt crystal aggregates morphologies from its vesiculated trichomes, and may use variable mechanisms for separating anions and cations of various salts. It was additionally found that salt crystals aggregates in this species …

Runtime Assertion Checking For Jml On The Eclipse Platform Using Ast Merging, Amritam Sarcar

Open Access Theses & Dissertations

The Java Modeling Language (JML) is a formal behavioral interface specification language for Java. It is used for detailed design documentation of Java program modules such as classes and interfaces. JML has been used extensively by many researchers across various projects and has a large and varied spectrum of tool support. It extends from runtime assertion checking (RAC) to theorem proving.

Amongst these tools, RAC and ESC/Java has been used as a common tool for many research projects. RAC for JML is a tool that checks at runtime for possible violations of any specifications. However, lately there has been a …

Nutrient Dynamics In A Created Desert Wetland: Implications For The Rio Bosque Wetlands Park, Ruth Rodriguez

Open Access Theses & Dissertations

Rio Bosque Wetland Park is an arid wetland currently under restoration, which primarily receives water inputs from the Bustamante Waste Water Treatment Plant (WWTP) during the non-irrigation season. Understanding the ability of a desert wetland to remove nutrients from the water column through uptake by primary producers or sediment transformations is key to justifying the protection and creation of other similar wetland sites. Nitrate concentrations tended to be reduced, relative to the inflow, near the outflow of the wetland.To further understand these trends, sediment nutrient release experiments and algal nutrient limitation experiments were completed. Sediment phosphorus release experiments indicated that …

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 …

A Characterization Of Pseudo-Orders In The Ring Zn, Jorge Ivan Vargas

Open Access Theses & Dissertations

Partially ordered sets are widely studied in algebra. The theory of lattice-ordered and partially-ordered rings is an important case. In this paper, we consider a more general relation: pseudo orders, which are relations that are reflexive and antisymmetric, but are not necessarily transitive. Analogously to partially-ordered rings, we study pseudo-ordered rings. We present a general characterization for pseudo-ordered rings, and then we focus on a specific structure: the ring Zn. Having the constraints of this ring, we are able to give the conditions under which Zn can be pseudo-ordered.

Introduction To Pseudo-Ordered Groups, Maria Dolores Cruz

Open Access Theses & Dissertations

We will give a definition, examples and basic properties of pseudo-ordered groups. These generalize partially-ordered groups. The pseudo-ordered groups have a compatible pseudo-order relation that may lack transitivity. Unlike partially-ordered groups, our groups can be finite and still admit a non-trivial pseudo-order. We will show necessary and sufficient conditions for a group to have a compatible pseudo-order. We also consider maximal pseudo-orders. We give a definition of a pseudo chain induced by a pseudo-order and characterize all pseudo chains on the group $\mathbb {Z}_{n}.$ We will calculate the number of non-isomorphic pseudo-orders on $\mathbb {Z}_{n}$ for $ n < 24.$

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 …

Microwave Assisted Solid-Supported Organic Synthesis: A Novel Methodology To Obtain 2,3-Disubstituted-1,4-Naphthoquinones, Israel Garcia-Martinez

Open Access Theses & Dissertations

This research focuses on the combinatorial solid phase organic synthesis (SPOS) of different bioactive compounds utilizing transition metal mediated reactions via microwave assisted organic synthesis (MAOS).

A microwave-assisted solid-supported Dötz benzannulation of chromium Fischer carbene complexes with various alkynes has been reported. The oxidative cleavage of the resulting resin-bound 1,4-naphthols affords 2,3-disubstituted-1,4-naphthoquinone derivatives in good to moderate yields with high purities. We demonstrated that solid phase organic synthesis of naphthoquinones via conventional heating is limited due to their long reaction times and high temperatures. The products decompose leading to low yields and purities.2 Microwave assisted synthesis of these naphthoquinones will …

Salsola Kali (Tumbleweed): A Possible Biomonitoring Device For The Detection Of Airborne Heavy Metals, Tenoch Benitez

Open Access Theses & Dissertations

Vehicular congestion generates particulate matter and contaminants such as lead, cadmium, copper, chromium, nickel, and zinc which have been detected in the U.S.-Mexico border region. To overcome the inconvenience of expensive sampling techniques, scientists started to assess air quality by using bioindicator plants, a technique called biomonitoring. Biomonitoring is an inexpensive and environmentally friendly approach to determine inorganic contaminants at trace levels. The purpose of this project was to determine the effectiveness of tumbleweed (Salsola kali) plants, sprayed with chelating agents, as a passive monitoring device to determine the possible presence of heavy metals in the ambient air around international …

Uptake Of Pahs And Metals By Plants In Arid Environment, Zarhelia Carlo

Open Access Theses & Dissertations

Study of plant uptake of PAHs with the concurrent presence of metals in laboratory conditions was done with the aim to resemble specific combinations of natural environment. Toxicological response of seedlings was tested to define treatment conditions or possible interferences. The levels of PAHs and metals in the treatments were set up to have no toxic effect on plant growth. The complexity of concurrent contamination was demonstrated in a laboratory with soil. No visual differences were observed among various dose treatments of Cu and Zn with organics three PAHs, Phenanthrene (Phen), Acetoanthrancene, and Benzo(a)pyrene (BaP). The metal analysis by ICP/OES …

Real-Time Image-Based Motion Detection Using Color And Structure, Manali Chakraborty

Open Access Theses & Dissertations

Motion detection is an important problem in computer vision and has multiple applications in the real world, including surveillance-related activities, gaming, and human-robot interactions. These systems need to be robust enough to handle fluctuations in light intensity and other external factors like noise and compression artifacts. In this thesis a method is proposed for detecting the regions of motion from a video sequence in real time. The main idea of this work is to detect motion based on both structure and color. Structure-based detection is carried out using information from the Census Transform computed on gradient images obtained with Sobel …

Symbiotic Effects Of The Fungus Glomus Sp. On Chromium(Iii), Chromium(Vi), And Lead(Ii) Uptake By Mesquite (Prosopis Sp.): A Novel Method To Remediate Heavy Metals, Jack A. Arias

Open Access Theses & Dissertations

The indiscriminate disposal of lead (Pb) and chromium (Cr) containing wastes has resulted in a detrimental impact on environmental health. Lead and Cr are in the EPA priority list due to their degree of toxicity on humans, animals, plants, and other living organisms. The removal of toxic wastes involves technologies that are expensive, sometimes incomplete, and could represent health hazards. In addition, site restoration after contaminant removal encompasses time and technological resources. Phytoremediation, the use of plants alone or associated with microorganisms, represents a potentially cost-effective option in the long term management of contaminated sites. Various plants known as "hyperaccumulators" …

Using Emotion To Gain Rapport In A Spoken Dialog System, Jaime Cesar Acosta

Open Access Theses & Dissertations

Although spoken dialog systems are becoming more widespread, their application is today limited largely to domains involving simple information exchange. To enable future applications, such as persuasion, new capabilities are needed. One barrier to the creation of such applications has been the lack of methods for building rapport between spoken dialog systems and human users, and more generally the inability to model the emotional and interpersonal aspects of dialog. This dissertation focuses on improving this.

A corpus of persuasive dialogs that in which a graduate coordinator informed undergraduate students about the graduate school option was analyzed. Although much of each …