Physical Sciences and Mathematics Commons^™

Using Environmental Dna Methods For Estimating Juvenile Chinook Salmon Abundance, Jacqueline Marie Bridegum

Cal Poly Humboldt theses and projects

In the Central Valley of California, stocks of Chinook Salmon are declining, and two out of the four ecotypes of Chinook Salmon within the Sacramento River system are federally listed. A monitoring network has been developed to estimate the abundances of downstream migrating Chinook Salmon smolts, but there is high uncertainty in these estimates due to low catch rates. Environmental DNA (eDNA) monitoring, which involves capture of genetic material that organisms release into their surrounding environment, has shown promise for estimating abundance of salmonids and could complement existing monitoring efforts and potentially reduce uncertainty in abundance estimates. This research project …

Investigating Van Der Waals Josephson Junctions With 2h-Nbse2 And 1t’-Wte2, Kristine Lorraine Haley

UNLV Theses, Dissertations, Professional Papers, and Capstones

Josephson junctions have garnered significant attention due to their unique electronic properties and applications in quantum devices. In this thesis, we investigate the fabrication processes and characterization of two-dimensional (2D) Josephson junctions consisting of layered van der Waals materials: niobium diselenide (2H-NbSe₂) and few layered tungsten ditelluride (1T’-WTe₂). The reduction of dimensionality can bring forth unique characteristics in certain materials that are not seen in their bulk counterparts, making them prime candidates for physical exploration. 2H-NbSe₂ is an s-wave superconductor at temperatures near and below 7 K. 1T’-WTe₂ is a semimetal in bulk but …

Electrical And Optical Characterization Of Two-Dimensional Semiconductors Using Ultrafast Spectroscopy, Pan Adhikari

All Dissertations

The emergence of two-dimensional (2D) layered materials provides unprecedented opportunities for studying excitonic physics due to the strong Coulomb interaction between the electron-hole pair. Because of the reduced dimensionality and weak dielectric screening, the exciton is stable at room temperature, unlike bulk semiconductors. The evolution from low to high carrier density for optical gain in 2D semiconductors involves insulating exciton gas, exciton condensation, co-existence of various excitonic complexes, electron-hole plasmas (EHPs), or electron-hole liquids (EHLs), leading to the Mott transition. Strong interaction among the excitons, such as exciton-exciton annihilation (EEA), serves as a hot-carrier generation. A bound exciton dissociates into …

Wetland Uranium Transport Via Iron-Organic Matter Flocs And Hyporheic Exchange, Connor J. Parker

All Dissertations

Uranium (U) released from the M-Area at the Department of Energy Savannah River Site into Tims Branch, a seasonal wetland and braided stream system, is estimated to be 43,500 kg between 1965 and 1984. The motivation for this work is the uranium’s persistence in the wetland for decades, where it is estimated that 80% of the U currently remains in the Tims Branch wetland. U has begun to incorporate into wetland iron (Fe) and carbon cycles, associating with local Fe mineralogy and deposits of rich wetland organic matter (OM). The objective of this work is to characterize the chemical phases …

Fate And Transport Of Toxoplasma Gondii Oocysts In Saturated Porous Media: Effects Of Electrolytes And Natural Organic Matter, Christian Pullano

All Theses

Toxoplasma gondii is a pathogenic microorganism that is currently a threat to public health. Understanding the fate and transport of T. gondii through the soil and groundwater is vital in determining the risk it poses to water resources and human health. The physico-chemical interactions between the groundwater and the bio colloid within an aquifer will dictate its mobility and its ability to infect humans. This research examines how various naturally occurring groundwater chemistries containing organic compounds and monovalent and divalent salt solutions will alter the fate and transport of T. gondii. Solutions containing various concentrations of humic acid, fulvic …

Competitive Sorption And Transport Of Heavy Metals In Soil And Mn Oxide-Coated Sand, Joshua Tyler Padilla

LSU Doctoral Dissertations

This study investigated the competitive sorption of Ni, Pb, and Zn as well as synergistic interactions between Ni and phosphate (P) in soils and Mn oxide-coated sand. During stirred-flow experiments, the sorption of heavy metal cations by Olivier soil was mutually reduced when applied simultaneously. When applied consecutively, the cation of higher affinity was able to displace the cation of lower affinity from the soil surface, however, no evidence for the reverse case was observed. A novel general exchange kinetics model was able to correctly describe such displacement. Competition between Ni and Zn mutually increased mobility in Olivier and Windsor …

Quantifying Surface Water Capture By Municipal Pumping Wells In An Urban Watershed Impacted By Road Salt, Austen York

Masters Theses

The Spring Valley sub-watershed is located within the Kalamazoo Township contains Spring Valley Lake, a man-made impoundment that ultimately discharges into the Kalamazoo River. Elevated chloride levels in pumped water from the Kalamazoo Station 14 municipal wellfield, located along the shoreline of Spring Valley Lake, has resulted in less than ideal corrosivity values for the water distribution system. Specific project objectives include: (1) identifying the cause of elevated chloride, (2) assessing surface water capture by the Station 14 wellfield, and (3) characterizing of water quality in Spring Valley Lake. Monitoring along a series of sampling transects spanning the sub-watershed, focused …

Studies Of The Planetary Boundary Layer And Their Impact On Air Pollution In A Semi-Arid Region With Complex Terrain, Nakul Nitin Karle

Open Access Theses & Dissertations

The adjacent cities of El Paso-Juárez, located in the Rio Grande Rift Valley and surrounded by complex mountainous terrain, have undergone rapid urbanization and industrial growth in the last few decades, accompanied by increasing substandard air quality episodes. Although numerous air quality studies were conducted in this semi-arid region in the past, none focused extensively on the Planetary Boundary Layer (PBL) contribution and impact on air pollutant concentrations. In this work, both the high and low ozone episodes from 2015 to 2020 were examined. Both modeling and experimental data of the PBL height (PBLH) were obtained and related to atmospheric …

Predicting Material Properties: Applications Of Multi-Scale Multiphysics Numerical Modeling To Transport Problems In Biochemical Systems And Chemical Process Engineering, Tom Pace

Theses and Dissertations--Physics and Astronomy

Material properties are used in a wide variety of theoretical models of material behavior. Descriptive properties quantify the nature, structure, or composition of the material. Behavioral properties quantify the response of the material to an imposed condition. The central question of this work concerns the prediction of behavioral properties from previously determined descriptive properties through hierarchical multi-scale, multiphysics models implemented as numerical simulations. Applications covered focus on mass transport models, including sequential enzyme-catalyzed reactions in systems biology, and an industrial chemical process in a common reaction medium.

Field And Numerical Evaluation Of Nitrogen Transport From Septic Systems In Surfical Aquifer Systems To Charlotte Harbor, Florida, Tanten T. Buszka

Masters Theses

Shallow water tables in coastal surficial aquifers limit effective treatment of septic effluent which can result in excess nutrient loading into nearby surface water bodies. Approximately 45,000 septic systems in Charlotte County, Florida transmit effluent into an under studied surficial aquifer and contribute to harmful algal blooms and outbreaks of E. coli. An undeveloped field site was characterized using standard hydrogeologic methods, including a one-year duration natural gradient tracer test, to obtain representative lithology of the sandy surficial aquifer and estimates of groundwater velocity, flow directions, effective porosity and dispersion. These data were used to support the development of a …

Influencing Factors On The Velocity And Temperature Of Propagating Fronts In Acrylate Composites, Samuel Morris Bynum

LSU Doctoral Dissertations

Thermal frontal polymerization is a type of polymerization in which a localized reaction zone propagates through an unstirred system. It is incumbent upon the production and transport of heat produced as a result of the exothermic reaction associated with free-radical polymerization. First discovered in the 1970s, frontal polymerization has been since utilized to produce a variety of different materials, utilizing a variety of different chemistries. The temperature of the propagating front and the velocity at which it propagates can be influenced via chemical or physical means. We show that through careful selection of monomers and control of the concentration of …

Breaking Coastal Hypoxia: Destratification Of Gulf Of Mexico Deadzone To Encourage Oxygen Transport Downwards To Maintain Marine Fauna, Veda Thipparthi

LSU Master's Theses

As a consequence of seasonal eutrophication and human input, a vast hypoxic area termed The Dead Zone develops every year in the Gulf of Mexico (GOM) during summer along the Louisiana coastline characterized by vertical seawater density-stratification with oxygen concentrations less than 2 mg.l^-1 at the seafloor. It poses a threat to bottom-dwelling faunae and their environment which has negative ecological and economic consequences. This project aims to mitigate hypoxia by employing mechanical impellers placed at strategic water depths and locations in the Gulf. Enhanced transport of oxygen results by mixing oxygen-enriched seawater at the surface, downward into the …

Environmental Assessment Of Arsenic And Mercury Levels At The Garfield Mill Site, Calico, California, Steven Gregory Thorp

Electronic Theses, Projects, and Dissertations

Environmental impacts of mining at Calico, California, are poorly understood in comparison to the details of its history of silver production. Human health risks associated with arsenic from the lode rock, as well as mercury from the silver milling process, include central nervous system damage, organ failure, and death. To quantify the potential human health risk and manage remediation of this site, tailings from the Garfield Mill site were digitally mapped and chemically analyzed by portable x-ray fluorescence, which permitted volumetric estimates of total mill tailings and the arsenic and mercury budget, as well as identification of anomalies in the …

Visualizing The Fate And Distribution Of Pahs In Spartina And Avicennia Tissues From Barataria Basin, La, Kristina Jeannette Sebastian

LSU Master's Theses

During crude oil spill events, vegetation in marsh environments sequester polycyclic aromatic hydrocarbons (PAHs) from the crude oil by partitioning from the air phase through the waxy cuticle on the leaf surface. Recent studies from Macondo oil-impacted marshes have demonstrated that cycling of low molecular weight petrogenic PAHs occurs through the cuticle and other leaf tissue. At present, our understanding of how PAHs travel through the cuticle is coarse and limited by grab samples across the entire leaf, which preventing a full understanding the dynamics of PAH cycling in this environment. Multiphoton (MP) confocal microscopy visualizes the distribution of PAHs …

Virus Adsorption To Colloids In Water: Interactions Between Bacteriophage Ms2, Kaolinite, And Fiberglass, Ashlee N. Ellis

Theses and Dissertations

Virus adsorption to colloidal particles is an important issue in the water quality community, and it is a particularly important issue for conventional wastewater treatment plants that accept biohazardous waste. Colloids impact the transport of viruses in engineered treatment systems, and they also provide protection against oxidants and other destructive mechanisms. This study evaluated the adsorption of bacteriophage MS2 to colloidal suspensions of kaolinite (KAO) and fiberglass (FG). A series of laboratory batch tests were carried out over a range of experimental conditions to determine kinetic rate constants and characterize bond strength, and computational experiments were done to assess both …

Column Tests Of Nitrate Breakthrough Behavior In Subsurface Sediments To Understand Transport In The Root-Zone, Rebecca Sally Haworth, Emma Rose Goodwin

Natural Resources Management and Environmental Sciences

Nitrate has become an increasingly ubiquitous pollutant in surface and groundwater, posing a threat to hu- man health and ecosystems. Nitrogen is a necessary nutrient for plant growth and is limiting in many soils. As a result, farmers often add nitrogen to soil in a usable form such as nitrate, nitrite, or ammonia through the addition of fertilizer.

Non-Centrosymmetric Superconductivity And Magnetism In The Presence Of Broken Symmetries, Mojammel Alam Khan

LSU Doctoral Dissertations

Non-centrosymmetric (NC) superconducting and magnetic compounds have been synthesized and investigated using magnetic, specific heat, and transport measurements, as well as by neutron scattering and quantum oscillations. The crystal structures of NC compounds are defined by the lack of an inversion center. In NC superconductors, a finite antisymmetric spin orbit coupling originating from broken inversion symmetry results in unconventional Cooper pairing. Instead of a single spin channel, the order parameter is a mixture of spin-singlet and spin-triplet states. For NC magnetic compounds, the antisymmetric and isotropic spin interactions compete, leading to a helical ground state.

We have studied the NC …

Electrodynamical Modeling For Light Transport Simulation, Michael G. Saunders

Undergraduate Honors Theses

Modernity in the computer graphics community is characterized by a burgeoning interest in physically based rendering techniques. That is to say that mathematical reasoning from first principles is widely preferred to ad hoc, approximate reasoning in blind pursuit of photorealism. Thereby, the purpose of our research is to investigate the efficacy of explicit electrodynamical modeling by means of the generalized Jones vector given by Azzam [1] and the generalized Jones matrix given by Ortega-Quijano & Arce-Diego [2] in the context of stochastic light transport simulation for computer graphics. To augment the status quo path tracing framework with such a modeling …

The Effects Of Tilted Magnetic Fields On Quantum Transport In 2d Electron Systems, William A. Mayer

Dissertations, Theses, and Capstone Projects

There exists a myriad of quantum transport phenomena in highly mobile 2D electrons placed in a perpendicular magnetic field. We study the effects of tilted magnetic field on these transport properties to understand how the energy spectrum evolves. We observe significant changes of the electron transport in quantum wells of varying widths with high electron densities at high filling factors. In narrow quantum wells the spin splitting of Landau levels due to Zeeman effect is found to be the dominant mechanism reducing Quantum Positive Magnetoresistance. In wider quantum wells with two populated subbands Magnetointersubband oscillations appear to exhibit effects from …

Exploration Of New Methods In Long Distance Transportation Data Collection And Tourism Travel In Vermont, Benjamin Kaufman

Graduate College Dissertations and Theses

ABSTRACT

Human transportation patterns have continued to shift and increase in rate as technology has made travel between spatially disparate locations more feasible. These movements are responsible for approximately one third of global carbon emissions, and account for one half of Vermont’s greenhouse gas output. Modeling transportation behaviors is difficult due to changing travel patterns and issues of surveying human participants. Long distance travel patterns are especially difficult and have not received the attention that urban mobility has within the literature.

In this Masters thesis, I describe current methods of transportation data collection and propose new methods, as well as …

Hydraulic And Electrokinetic Delivery Of Remediants For In-Situ Remediation, Ahmed I. A. Chowdhury

Electronic Thesis and Dissertation Repository

Nano-scale zero valent iron (nZVI) has shown promising mobility and in-situ reactivity with chlorinated volatile organic compounds when injected into saturated porous media. The current study evaluated nZVI mobility and subsequent reactivity with in-situ contaminants in a variably saturated porous media. The nZVI particles, synthesized onsite at subzero temperatures, demonstrated complete trichloroethene (TCE) degradation within the target area. Furthermore, a three dimensional finite difference model (CompSim) was utilized to investigate nZVI mobility in variably saturated zones. Model predicted well head data were in very good agreement with field observations. Simulation results showed that the injected slurry migrated radially outward from …

Synthesis And Characterization Of Amphiphiles For Mammalian Cell Transfection And Antimicrobial Activity, Joseph William Meisel

Dissertations

Amphiphiles are molecules that contain both water-soluble and water-insoluble components. The dual nature of these molecules engenders remarkable properties including the ability to self-assemble into ordered structures. Cell membranes are composed of amphiphilic phospholipids that organize into a bilayer motif. Synthetic amphiphiles can interact with natural membranes and influence the transport of molecules across the cell membrane. The work elaborated in this report employs amphiphiles to co-assemble with DNA and transport the genetic material across cell membranes. First, a simplified method for interacting DNA with amphiphiles was developed. Second, a series of known ion-transporting compounds were assayed for their interaction …

Thermal Fluctuations Tunneling In Doped Conjugated Polymers, Troy C. Stedman

USF Tampa Graduate Theses and Dissertations

The possibility of using conducting polymers as organic alternatives to widely used inorganic materials for thermoelectric (TE) applications has received much attention in the past few decades. Since conducting polymers are generally inefficient compared to inorganic TE materials, research into their underlying transport mechanisms is required to improve their efficiency. We use a model based on the effects of local thermal fluctuations to characterize the transport in conducting polymer composites. With this model, full linear responses for the current and electronic heat current are obtained. From these responses, the local temperature dependent conductivity, electronic contribution to the thermal conductivity, and …

Spectroscopic Studies On The Interaction Of Cetylpyridinium Bromide Monohydrate And Bromothymol Blue With Polymerized Silica, James Siegenthaler

All Master's Theses

The design and implementation of a controlled macromolecular chemical transport system could greatly advance switchable chemical reactions and be applicable for targeted drug delivery, intelligent inks, and nanotechnology. To better understand the mechanisms of function for a switchable macromolecular transport system, preliminary work has been completed that studies the transport of bromothymol blue (BB) facilitated by cetylpyridinium bromide monohydrate (CPBM) to a silica surface that has been modified with Poly(styrene-co-maleic anhydride), a pH switchable polymer. Ultraviolet spectroscopic trials were conducted measuring the absorbance of BB and CPBM at 3 pH levels and 3 different surface reactivity levels of …

An Examination Of Radionuclide Transport In The Vadose Zone Using Field Lysimeters, Michael Witmer

All Theses

Understanding how radionuclides interact in the subsurface is important for the remediation of contaminated sites, assessment of risk due to radioactive waste disposal, and designing new radioactive waste management strategies. The current understanding of the geochemical behavior of radionuclides in the subsurface and more specifically the vadose zone has been developed through reactive transport modeling supplemented by laboratory experiments. Interactions between radionuclides with the mineral particles and organic matter in the vadose zone can be very complex and while laboratory experiments produce valuable data, few controlled, intermediate scale transport studies have been performed. In order to accurately predict vadose zone …

Physically Based Preconditioning Techniques Applied To The First Order Particle Transport And To Fluid Transport In Porous Media, Michael Rigley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Solving linear systems is at the heart of many scientific applications from the PreAlgebra's student solving for x and y for basic geometry problems to the computational scientist solving billions of equations with billions of variables for weather forecasting, modeling fusion reactions, or web search algorithms. In this study we look at improving the efficiency of solving large linear systems that result from two applications. The first includes linear systems that result from solving differential equations for the movement of atomic particles in particle emitting, void, and absorbing regions. The second includes solving linear systems that result from solving differential …

Geochemistry And Inorganic Carbon Transport Of A Glacial Till Drumlin At A Road Salt Facility, Houbao Li

Open Access Dissertations

Investigations were conducted at a salt/premix storage facility lying on top of a glacial drumlin near the coastline in eastern Massachusetts, to characterize salt contaminated groundwater. Groundwater hydrogeochemical variations at different depths were determined based on ten years of monthly or quarterly water quality data from 54 monitoring wells. Groundwater was grouped in three water categories – shallow, middle and deep. Hydrogeochemical characterization indicates that the dominant water types are Na-Cl, Na-Ca-Cl and Ca-HCO3 from the shallow to deep water group. Rock weathering is the dominant hydrogeochemical process for deep water group, whereas salt water percolation and cation exchange control …

Parallel Heat Transport In Magnetized Plasma, Mukta Sharma

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A huge global increase in energy use is inevitable, so there is an urgent need to seek cleaner ways of producing energy on large scales. Fusion is the energy source of the universe and a promising way to fulfill energy needs of mankind for many centuries to come. It offers important advantages as a safe, sustainable, and environmentally friendly source of energy. The International Thermonuclear Experimental Reactor (ITER) aims to demonstrate magnetic fusion is an energy source of the future. The goal of ITER is to produce 500 MW of fusion power given 50 MW of input power—or ten times …

Theoretical Studies Of Nanostructure Formation And Transport On Surfaces, Maral Aminpour

Electronic Theses and Dissertations

This dissertation undertakes theoretical and computational research to characterize and understand in detail atomic configurations and electronic structural properties of surfaces and interfaces at the nano-scale, with particular emphasis on identifying the factors that control atomic-scale diffusion and transport properties. The overarching goal is to outline, with examples, a predictive modeling procedure of stable structures of novel materials that, on the one hand, facilitates a better understanding of experimental results, and on the other hand, provide guidelines for future experimental work. The results of this dissertation are useful in future miniaturization of electronic devices, predicting and engineering functional novel nanostructures. …

Sediment Impact On The Formation Of Hypoxic Waters In The Northern Gulf Of Mexico: A Synthesis Of Sediment Texture, Composition, Erodibility And Transport, Rangley Claude Mickey

Electronic Theses and Dissertations

Annual hypoxic events have been found to occur over the past several decades in the northern Gulf of Mexico (nGOM) and have prompted researchers to begin studying the mechanisms that control hypoxia formation so they may advise policy makers on the appropriate mitigating responses. This has led to the development of 3-dimensional modeling systems that incorporate marine physical, biological, geological, and chemical processes that may impact the formation and duration of hypoxic regimes in the nGOM. This study used field, laboratory, and modeling techniques to examine how sediment may be eroded from the seabed and where/how it is transported across …