Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

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 …

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" …

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 …

Taste Of Dirt, Brianna Lynn Heisey

Open Access Theses & Dissertations

Taste of Dirt is a novel about a young female wildland fire fighter and her travels across the western U.S with her fire crew. The forest, the open road, the animals, and the men and women she meets along the way help her overcome her fears and re-discover her place in nature. This Thesis is approximately 240 pages and includes a dedication, acknowledgements, a table of contents, a 25 page introduction, 16 complete chapters and a curriculeam vita. Enjoy.

A Retrospective Study Of Dust Storms And Respiratory Hospitalizations In El Paso, Texas Using A Case-Crossover Study Design, Yanlei Peng

Open Access Theses & Dissertations

Dust storms frequently occur in El Paso, Texas, but little is known about their respiratory health effects. The association between dust storm and hospitalization for respiratory illness will be studied through a case-crossover study design. The goal is to ascertain the effect of dust storms, adjusted for weather and other pollutants, and to explore the potential harmfulness for different subgroups of residents. A case-crossover study allows patients to serve as their own controls, in order to reduce confounding. The history, relationship, and application of the case-control and case-crossover study designs are reviewed in this thesis. The estimating equations for conditional …

By-Product Synergy In The Textile Industry: Indigo Waste Recovery In The Denim Finishing Process, Dennis Wambuguh

Open Access Theses & Dissertations

Textile dyeing effluents present a substantial environmental problem, primarily because such effluents contain high concentrations of waste dyes, dye-products, and variable salts. The stonewashing process for the degradation of blue indigo to create a `faded' look in blue denim results in high concentrations of indigo dye waste in the resulting effluent and because indigo is very difficult to decompose biologically, the effluent ends up in the environment, raising aesthetic concerns and damaging the integrity of the rceiving streams. Wastewater containing indigo is characterized by a moderate amount of chemical oxygen demand (COD), pH, suspended solids, dissolved solids and a dark …

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 …