Physical Sciences and Mathematics Commons^™

Two Dimensional Mathematical Model Of Fluid Flow In A Growing Solid Tumor, Adriana Gracia

Theses and Dissertations - UTB/UTPA

We investigate the problem of steady and unsteady fluid flow in a growing solid tumor. We develop a mathematical model for the two dimensional fluid flow in a spherical tumor where the spatial variations of the interstitial velocity, interstitial pressure and the drug concentration within the tumor are, in general, with respect to the radial distance and the latitudinal angle in the spherical coordinates. The expressions for radial and latitudinal variations of the interstitial velocity, interstitial pressure, and the two investigated drug concentrations were determined analytically. We calculated these quantities in the tumor as well as in a corresponding normal …

Watershed Delineation In The Field: A New Approach For Mobile Applications Using Lidar Elevation Data, Samuel Adam Noel

Open Access Theses

With the advancement of mobile devices, opportunities to take watershed management tasks out of the office and into the field can be realized. In turn, field workers can utilize these technologies to expedite the decision-making process so that they may focus on meeting with clients and addressing agricultural watershed management issues. High-resolution (∼1.5 m postspacing) elevation data gathered by light detection and ranging (LiDAR) provides the topographic detail necessary to model hydrology at the field-scale (∼1 km2).

Non-artifactual surface depressions lead to erroneous surface flow patterns when using existing algorithms. So a sequential depression-filling algorithm (SDFA) has been developed to …

The Barriers To Adopting Composting Toilets Into Use In Urban And Suburban Locations In The United States, Julia Branstrator

Open Access Theses

The amount of fresh water available in the world is a finite resource. Large quantities of the fresh water are located in remote locations, while more accessible sources of fresh water are disproportionately distributed around the world. Some populations lack reliable access to clean water for daily life, making the routine use of potable water in toilets of upper-income countries a questionable practice in terms of resource responsibility, energy use, and sustainable infrastructure. The innovative nature of composting toilets offers potential solutions to the downfalls of conventional, waterborne toilets. However, the path to adoption of composting toilets has encountered barriers …

Energy Analysis Of Cool, Medium, And Dark Roofs On Residential Buildings In The U.S., Michael A. Dunbar

Open Access Theses

This study reports an energy analysis of cool, medium, and dark roofs on residential buildings in the U.S. Three analyses were undertaken in this study: energy consumption, economic analysis, and an environmental analysis. The energy consumption reports the electricity and natural gas consumption of the simulations. The economic analysis uses tools such as simple payback period (SPP) and net present value (NPV) to determine the profitability of the cool roof and the medium roof. The variable change for each simulation model was the roof color. The default color was a dark roof and the results were focused on the changes …

Systematic Analysis Of Drainage Events In Free Draining And Managed Subsurface Drainage Systems, Guy Bou Lahdou

Open Access Theses

Understanding the hydrologic controls that regulate outflow from free and managed subsurface drainage systems during drainage events can offer improved insight on the overall functioning and effectiveness of the systems so that they can be better managed or retrofitted to increase their environmental benefits. This study used drainage, precipitation, water table, and soil moisture data from a monitoring site located in east central Indiana to investigate the event hydrology of 22 drainage events in free and managed subsurface drainage systems. Relationships between event drainage volume, drain flow hydrograph metrics, column soil moisture, water table depth, and precipitation characteristics were explored …

Leaching Characteristics Of Selenium From Coal Fly Ash, Mark Allen Cantrell

Graduate Theses and Dissertations

Selenium (Se) contamination can be a potential groundwater concern near un-lined coal ash landfills. Out of all the Environmental Protection Agency (EPA) priority and non-priority pollutants, Se has the narrowest range between what is considered beneficial and detrimental for aquatic and terrestrial organisms. The effects of ash type (i.e., fresh and weathered), water-extractant type (i.e., deionized water, rainwater, and groundwater), and extraction time (i.e., 2- and 6-hours) on Se, arsenic (As), and chromium (Cr) concentrations were investigated from Class C, subbituminous coal fly ash produced at the Flint Creek Power Plant located in Benton County, AR. Water-extractable Se concentrations differed …

Deforestation Of Cloud Forest In The Central Highlands Of Guatemala: Soil Erosion And Sustainability Implications For Q'Eqchi' Maya Communities, Ian Christopher Pope

Open Access Theses

Understanding the nexus between deforestation, food production, land degradation, and culture contributes knowledge that is useful for development practitioners working to enhance conservation and food security. Documenting deforestation and soil erosion in the Sierra Yalijux and Sierra Sacranix in the Central Highlands of Guatemala adds new knowledge about the rates and dynamics of deforestation and land degradation in areas with unique and sensitive cloud forest ecosystems. It also suggests possible areas of emphasis for efforts targeted at combining cloud forest conservation with sustainability for indigenous Q'eqchi' communities. In addition, this work contributes to a small but growing body of literature …

Pharmaceuticals And Personal Care Products: Emerging Contaminants In Aquatic Ecosystems, Jenny E. Zenobio

Open Access Theses

In recent years, the presence of pharmaceuticals and personal care products (PPCPs) in aquatic systems has led to research on their fate and effects. PPCPs have been found in mixture in wastewater effluents, surface, ground, and drinking water at low concentrations from areas of intense urbanization. Although adverse effects to human health from the current environmental concentrations are unlikely, the impacts to ecological receptors are not clear. We performed field and laboratory studies to quantify and evaluate effects of PPCPs on fish. First, a field study was conducted at the Baca National Wildlife Refuge, Colorado (2010-2012) because a portion of …

Roundup Ready Nation: The Political Ecology Of Genetically Modified Soy In Argentina, Amalia Leguizamon

Dissertations, Theses, and Capstone Projects

This dissertation is a case study of agrarian transformation in an agro-export society, Argentina. I study the process of adoption of the technological package of genetically modified (GM) soy in the Argentine countryside, its socio-ecological consequences, and Argentines' responses to it. In particular, this research addresses Argentina's unique situation of being a developing country that has positively embraced the biotechnology of GM seeds as a key accumulation strategy without the emergence of major contestation against GM soy monocropping. In order to answer the puzzle of quiescence, I look at how power relations structure access to social and environmental goods and …