Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- University of Arkansas, Fayetteville (3)
- University of Tennessee, Knoxville (3)
- Michigan Technological University (2)
- University of Montana (2)
- University of San Diego (2)
-
- West Virginia University (2)
- Air Force Institute of Technology (1)
- American University in Cairo (1)
- Bowling Green State University (1)
- California State University, San Bernardino (1)
- City University of New York (CUNY) (1)
- Coastal Carolina University (1)
- Colby College (1)
- Duquesne University (1)
- Georgia Southern University (1)
- Kennesaw State University (1)
- Louisiana State University (1)
- Missouri State University (1)
- Nova Southeastern University (1)
- Seattle Pacific University (1)
- Southern Methodist University (1)
- Stephen F. Austin State University (1)
- The University of Maine (1)
- The University of San Francisco (1)
- University of Central Florida (1)
- University of New Mexico (1)
- University of New Orleans (1)
- Western University (1)
- Wilfrid Laurier University (1)
- William & Mary (1)
- Keyword
-
- Dissolved Organic Carbon (2)
- Wastewater (2)
- 13C Suess effect (1)
- 3D geometric morphometrics (1)
- AMIDOXIMATED (1)
-
- Acetic acid (1)
- Acidity (1)
- Advanced oxidation processes (1)
- Aerated and de-aerated feeds (1)
- Agricultural History (1)
- Agricultural Science (1)
- Agriculture (1)
- Air quality (1)
- Algal bloom (1)
- Alginate (1)
- Aluminum dosing (1)
- Analysis and extraction of metals from a soil matrix (1)
- Ancestral Pueblo (1)
- Aquatic (1)
- Aquatic Sampler (1)
- Arsenic (1)
- Artisanal mines (1)
- Atom transfer radical polymerization (1)
- BLM (1)
- Benzene (1)
- Biochemistry (1)
- Biogeochemistry (1)
- Biology (1)
- Biopolymer (1)
- Breslow (1)
- Publication
-
- Electronic Theses and Dissertations (4)
- Graduate Theses and Dissertations (3)
- Masters Theses (3)
- Dissertations, Master's Theses and Master's Reports (2)
- Graduate Student Theses, Dissertations, & Professional Papers (2)
-
- Graduate Theses, Dissertations, and Problem Reports (2)
- Honors Projects (2)
- Honors Theses (2)
- Theses (2)
- Theses and Dissertations (2)
- All HCAS Student Capstones, Theses, and Dissertations (1)
- Anthropology ETDs (1)
- Civil and Environmental Engineering Theses and Dissertations (1)
- Dissertations, Theses, and Capstone Projects (1)
- Electronic Theses and Dissertations, 2020- (1)
- Electronic Theses, Projects, and Dissertations (1)
- Electronic Thesis and Dissertation Repository (1)
- LSU Doctoral Dissertations (1)
- MSU Graduate Theses (1)
- Master of Science in Chemical Sciences Theses (1)
- Master's Projects and Capstones (1)
- Theses and Dissertations (Comprehensive) (1)
- Undergraduate Honors Theses (1)
- University of New Orleans Theses and Dissertations (1)
Articles 1 - 30 of 38
Full-Text Articles in Physical Sciences and Mathematics
In Situ Study Of Geological Fluid Inclusions Using 23na Nuclear Magnetic Resonance Spectroscopy, Stephen Pilar
In Situ Study Of Geological Fluid Inclusions Using 23na Nuclear Magnetic Resonance Spectroscopy, Stephen Pilar
Electronic Thesis and Dissertation Repository
23Na Magic Angle Spinning Solid State Nuclear Magnetic Resonance (MAS SS NMR) spectroscopy has been used to study natural geological samples of halite, fluorite, and quartz to evaluate the efficacy of NMR spectroscopy for in situ fluid inclusion analysis. NaCl calibration standards yielded a strong linear correlation (R2=0.9919) for salinity, albeit only over a ~1 ppm breadth of chemical shift. Fluid inclusions were successfully identified in all three types of minerals studied using MAS NMR. Chemical analysis with Inductively Coupled Plasma -- Mass Spectrometry (ICP-MS) was employed to quantify elemental contaminants in halite samples. Powder X-Ray Diffraction …
Formation Of Reactive Nitrogen Species During Dichloramine Decay And Their Impact On N Nitrosodimethylamine Formation Under Drinking Water Conditions, Huong Thu Pham
Graduate Theses and Dissertations
NDMA occurrence and formation pathways in drinking water systems are reviewed and NDMA yields are compared on the basis of disinfectant type, water chemistry, and precursor category. In chloramination, despite monochloramine being the predominant species between pH 7-9, evidence suggests that dichloramine is the primary species involved in NDMA formation. This is somewhat confounding as NDMA yields are maximal at pH 9, yet at pH 9 dichloramine decays faster than it forms and hence is present at trace levels; additionally, the proposed mechanism involves a spin-forbidden incorporation of dissolved oxygen as a triplet, which is presumably kinetically slow. This review …
Influence Of Physical Variability Of Highly Weathered Sedimentary Rock On Nitrate In Area 3 Of The Enigma Field Research Site At Y-12, Erin Kelly
Masters Theses
Uranium processing and waste storage in unlined waste ponds leached contaminants into the groundwater at Y-12, Oak Ridge, Tennessee, from the 1950s to 1980s. Groundwater wells near the S-3 ponds have had the highest nitrate concentrations of groundwater anywhere in the world (>10,000 mg/L). For reference, the maximum contaminant level for nitrate in drinking water set by the U.S. Environmental Protection Agency is 10 mg/L. Since 2012, the ENIGMA (Ecosystems and Networks Integrated with Genes and Molecular Assemblies) group has been characterizing, monitoring, and conducting field experiments to understand the interactions between contaminants, microbes, and the subsurface. The goals …
Development Of An Lcms Analytical Method With Applicability To Determination Of Trace Level Explosives In Environmental Waters, Cristina I. Veresmortean
Development Of An Lcms Analytical Method With Applicability To Determination Of Trace Level Explosives In Environmental Waters, Cristina I. Veresmortean
Dissertations, Theses, and Capstone Projects
Traces of explosives and their degradation products present in explosives contaminated sites from military sources, such as training facilities, impose a great concern over the public health and our eco-system. This work is centered around finding an efficient way to extraction of these chemicals from water samples and their analysis using advanced separation technology: LC-MS/MS Shimadzu Prominence 8050 and AB Sciex Trap 4000 LC-MS/MS. Different extraction methods will be proposed, along with chromatographic and mass spectroscopy method development. Dependent on the target analyte polarity, thermal degradation, solubility and type of matrix, an appropriate method of analysis will be established. The …
To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand
To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand
Electronic Theses and Dissertations
Ever since the eighteenth century, experts have tried to tell farmers how to farm. The agricultural enlightenment in Europe marked the beginning of a long arc of new experts aiming to change agricultural knowledge and practice. This dissertation analyzes the pivotal period in the late nineteenth and early twentieth century in Germany and the United States when scientists, improvers, and market agents began to develop comprehensive ways to communicate agricultural innovation to farmers. In a functional approach to analyzing the negotiation of agricultural knowledge through its communication in things, words, and practices, this dissertation argues that the process of change …
The Variability Of Seawater Carbonate Chemistry In Two Florida Urban Mangrove Ecosystems, Alexandrina R. Rangel
The Variability Of Seawater Carbonate Chemistry In Two Florida Urban Mangrove Ecosystems, Alexandrina R. Rangel
All HCAS Student Capstones, Theses, and Dissertations
Anthropogenic carbon dioxide (CO2) emissions into the atmosphere are yielding serious impacts across the world’s ocean, including ocean acidification, sea level rise, and increasing seawater temperature. However, these changes are not occurring uniformly across all marine ecosystems. Coastal ecosystems, such as mangroves, already experience extreme and variable environmental conditions due to natural biogeochemical and physical processes. The goal of this study was to document small-scale variability in two urban mangrove ecosystems to gain insight into how ocean acidification will manifest within these systems. Using a stand-up paddleboard, a suite of sensors, and traditional bottle sampling techniques, we measured …
Impacts Of Oil And Gas Wastes On Landfill Leachate, Sewage Treatment Plants, And The Environment, Lauren Badertscher
Impacts Of Oil And Gas Wastes On Landfill Leachate, Sewage Treatment Plants, And The Environment, Lauren Badertscher
Electronic Theses and Dissertations
Between January 2011 and March 2021 oil and gas wells in Pennsylvania produced
305,637,795 barrels of liquid waste and 6,992,957 tons of solid waste with the majority from
Marcellus Shale unconventional wells. This waste is not considered hazardous and over 89% of
the solid waste generated by unconventional and conventional oil and gas extraction has been
disposed of in landfills over the past decade. This study examined trends in the quantity of waste
produced and methods of disposal. Landfills accepting this waste were identified and their
general method of leachate treatment, using onsite facilities or offsite at wastewater treatment
plants, …
Development Of Standard Operating Procedure With Modified Method To Quantify Benzene And Other Volatile Organic Compounds In Air Samples Using Gas Chromatography, Heather Hall
Electronic Theses and Dissertations
Stephen F. Austin State University (SFASU) Department of Environmental Science has recently invested in a gas chromatograph which can be used to analyze air samples for volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, and xylenes (BTEX). The goal of this project was to develop a standard operating procedure (SOP) and modify the current method for the detection of VOCs associated with oil and gas drilling activity to accommodate the equipment and capabilities of SFASU Environmental Assessment Lab. This study aims to provide the framework for future research in air quality monitoring in the Eagle Ford Shale area. An …
Laboratory Investigation Of Cyanide Evolution During Reaction Between Hypochlorous Acid And Glycine, Luz Chavez
Laboratory Investigation Of Cyanide Evolution During Reaction Between Hypochlorous Acid And Glycine, Luz Chavez
Electronic Theses, Projects, and Dissertations
Fresh water treatment and conservation is of great importance in a society with a growing population. Ensuring water safety is a crucial task for water treatment plants. Advances in science and technology have allowed for the testing and study of potentially harmful side substances produced by water sanitation methods, one of those substances is cyanide (-CN). Previous research correlated a significant increase of cyanide levels in effluent water sanitized with a chlorination method. Research has also proposed a mechanism for the formation of cyanogen chloride (CNCl) from reactions with amino acids during the chlorination process. Flow injection analysis was chosen …
Physiological, Biochemical, And Metabolic Responses Of Wheat (Triticum Aestivum) Exposed To Perfluorooctanesulfonic Acid (Pfos), Polycarp Chidiebere Ofoegbu
Physiological, Biochemical, And Metabolic Responses Of Wheat (Triticum Aestivum) Exposed To Perfluorooctanesulfonic Acid (Pfos), Polycarp Chidiebere Ofoegbu
MSU Graduate Theses
The effects of perfluorooctanesulfonic acid (PFOS) on agricultural plants is a serious environmental concern that needs to be addressed. PFOS is a member of a class of organic chemical compounds known as per and polyfluoroalkyl substances (PFAS). These compounds are utility chemicals in household, commercial, and industrial items, but have become environmental contaminants of global concern. Full lifecycle and short-term exposure studies of wheat grown in soil amended with 0, 25, and 50 mg/kg PFOS were conducted to assess the impacts of PFOS on wheat. PFOS uptake analysis, physiological assays, elemental analysis, and metabolomics were carried out in the full …
Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown
Dissolved Organic Carbon And The Potential Role To Stream Acidity In The Great Smoky Mountains National Park, Jason R. Brown
Masters Theses
A substantial societal shift towards environmental awareness has focused research efforts on the impacts of pollution on natural landscapes. Improvements to pollutant regulations and technology have resulted in sizeable reductions of atmospheric deposition of anthropogenic acids, especially nitrates and sulfates, which has altered the role of these ions in the environment. As such, understandings of environmental chemistry dynamics have required regular updating.
Through the National Park Service Vital Signs monitoring program, increases in precipitation pH observed in Great Smoky Mountains National Park (GRSM) has been attributed to the reduction of inorganic acid concentrations. Unfortunately, these improvements have not been uniformly …
Desorption Of Non-Exchangeable Radiocesium In Soil From Fukushima Prefecture, Japan, Grayson Phillips
Desorption Of Non-Exchangeable Radiocesium In Soil From Fukushima Prefecture, Japan, Grayson Phillips
Master of Science in Chemical Sciences Theses
The Fukushima Daiichi Nuclear Powerplant was struck by an earthquake and a tsunami resulting in the meltdown of four of the six reactor cores operating at the plant. As a result, nuclear waste was released from the plant, contaminating the soil in the region. Most of the contamination was sequestered within the few inches of the soil but unluckily the contamination, radiocesium formed a non-exchangeable bond. The Japanese government bagged this soil and has stored it in fields surrounding the exclusion zone. Long-term storage facilities have not been determined. This is a study of the available resources to determine if, …
Investigation Of Factors Influencing Recombination Versus Disproportionation Of Complex Radicals Formed By C-N Homolysis Of Breslow Type Intermediates And Related Compounds, Taylor Burnett
Graduate Theses and Dissertations
Electron rich enamines are capable of C-N bond homolysis and subsequent recombination and/or disproportionation. It is unclear what causes these radicals to undergo recombination or disproportionation. Density Functional Theory (DFT) calculations do not provide a transition state for the recombination and disproportionation processes and therefore they cannot be used to predict the favorable reaction. Breslow intermediates formed by deprotonation of thiazolium salts and reaction with aromatic aldehydes are examples of electron rich enamines. These breslow intermediates can undergo C-N bond homolysis to form a radical pair the either recombine or disproportionate. Upon investigation of the factors influencing recombination and disproportionation, …
Engineered Nanostructured Nitrogen-Doped Carbon Network (Ndc) Electrodes With Unprecedented Cycling Stability For Water Capacitive Deionization In Harsh Conditions, Soha Essam Anwar
Theses and Dissertations
Capacitive deionization (CDI) is a feasible low-cost desalination technique for low-to-medium (brackish) salinity water. However, cycling stability and regeneration of the CDI electrodes are the bottlenecks hindering the practical application of the technology on large scale. Oxidation of the electrodes during the sequential adsorption-desorption processes is one of the most challenging problems hindering their long-term cycling performance. Herein, we demonstrated the ability to design and fabricate exceptionally stable CDI electrodes via a one-pot pyrolysis protocol. The optimized pyrolysis of nitrogen-carbon precursors at different temperatures enabled the fabrication of carbon materials with a controlled amount nitrogen dopant (NDCs) with exceptional cycling …
Isolation And Determination Of The Composition And Structural Components That Comprise Dissolved Organic Matter Using Normal Phase Liquid Chromatography, Jonathan A. Long Jr
Isolation And Determination Of The Composition And Structural Components That Comprise Dissolved Organic Matter Using Normal Phase Liquid Chromatography, Jonathan A. Long Jr
University of New Orleans Theses and Dissertations
A comprehensive understanding of the reactivity associated with organic carbon is critical for recognizing the behavior of newly formed compounds in aquatic environments. In an effort to study the reactivity of complex mixtures, understanding the different processes affiliated with them are key. Understanding the reactivity associated with organic carbon can help to improve chromatographic separation. Using a combination of light and heavy crude oil, a separation procedure was developed to obtain a complete representation of the aromatic subfraction of the crude oil sample. The crude oils were separated into four distinct fractions based on the number of condensed aromatic rings …
Modeling Biliary Polycyclic Aromatic Hydrocarbon Metabolites In Fish Using High Performance Liquid Chromatography With Fluorescence Detection, Principal Component Analysis, And Partial Least-Squares Analysis, Joshua C. Padilla
Honors Projects
Polycyclic aromatic hydrocarbons (PAHs) constitute a diverse class of highly toxic, ubiquitous environmental pollutants, and are thus of high interest in environmental monitoring and regulation. In this study, biliary samples of English soles Parophrys vetulus and smallmouth bass Micropterus dolomieu from Seattle waterways, and chum salmon Onchorynchus keta from the north Pacific Ocean were analyzed by high performance liquid chromatography with fluorescence detection (HPLC-FLD) to gauge PAH exposure. Samples were profiled in three broad molecular weight categories, to capture naphthalene-like (NAPH), phenanthrene-like (PHEN), and benzo[a]pyrene-like (BAP) metabolites. While quantification was not achieved for the chum salmon, the semi-quantitative measurements of …
Addressing Uncertainties Of Polychlorinated Biphenyls In Schools, Alice Fan
Addressing Uncertainties Of Polychlorinated Biphenyls In Schools, Alice Fan
Master's Projects and Capstones
Despite the potential neurological health deficits resulting from polychlorinated biphenyls, there is a lack of inhalation studies and regulations to protect students and teachers who are widely exposed to PCBs in older (1950 to 1979) schools. To estimate the extent of PCB detections in Los Angeles County schools, I applied a mathematical model to estimate the range of PCB detections in schools built between 1950 and 1984. I estimate the range of 17-34% PCB detections of open schools within Los Angeles County. Next, I reviewed exposure tools provided by the US EPA to bridge the uncertainty gaps between ingestion and …
Effects Of Environmental Change On Ancestral Pueblo Fishing In The Middle Rio Grande, Jonathan W. Dombrosky Dr.
Effects Of Environmental Change On Ancestral Pueblo Fishing In The Middle Rio Grande, Jonathan W. Dombrosky Dr.
Anthropology ETDs
It has long been assumed that fishes were unimportant in the diet of past Pueblo people in the U.S. Southwest. Yet, small numbers of fish remains are consistently recovered from Late pre-Hispanic/Early Historic archaeological sites in the Middle Rio Grande of New Mexico. The end of drought conditions may have impacted food choice and fishing decisions during this time. I use behavioral ecology to understand how fishing could have been an optimal food-getting strategy for Ancestral Pueblo farmers. Stable isotope analysis offers a way to account for environmental change. I provide a refined 13C Suess correction model to support …
Isolated Point Discharges Into Coastal Swashes As Nutrient Sources To Coastal Waters, Mary E. Olsen
Isolated Point Discharges Into Coastal Swashes As Nutrient Sources To Coastal Waters, Mary E. Olsen
Honors Theses
Coastal water quality in the Grand Strand of South Carolina is directly influenced by human activities. Nutrient-rich runoff, stemming from numerous anthropogenic sources, finds its way into coastal waters through freshwater inputs often through tidal creeks, termed swashes. In order to better describe the amount of nutrient inputs into Singleton Swash and White Point Swash, we examine anthropogenic runoff from isolated identifiable point discharges and their nutrient concentrations. We report concentrations of dissolved inorganic nitrogen (DIN, as the sum of nitrate, nitrite and ammonium) and phosphate in discharge and creek water. We hypothesize that nutrient concentrations of isolated, minor point …
Pectin And Alginate Extraction To Treat Liquid Cafo Manure, Clare Sunderman
Pectin And Alginate Extraction To Treat Liquid Cafo Manure, Clare Sunderman
Honors Projects
For this project, various extraction methods were used to extract pectin from Pastinaca Sativa and alginate from Macrocystis. These extractions were then dried and used in treating 250mL of manure along with a CaCl2 or FeCl3 coagulant. It was found that CaCl2 was not as effective as FeCl3 in coagulating manure. But the results obtained suggest that pectin and alginate obtained with a simpler extraction method is just as effective as the highly purified and refined pectin and alginate produced for the food industry, in the treatment of CAFO manure. The liquid portion of the …
Molecular Cluster Fragment Machine Learning Training Techniques To Predict Energetics Of Brown Carbon Aerosol Clusters, Emily E. Chappie
Molecular Cluster Fragment Machine Learning Training Techniques To Predict Energetics Of Brown Carbon Aerosol Clusters, Emily E. Chappie
Undergraduate Honors Theses
Density functional theory (DFT) has become a popular method for computational work involving larger molecular systems as it provides accuracy that rivals ab initio methods while lowering computational cost. Nevertheless, computational cost is still high for systems greater than ten atoms in size, preventing their application in modeling realistic atmospheric systems at the molecular level. Machine learning techniques, however, show promise as cost-effective tools in predicting chemical properties when properly trained. In the interest of furthering chemical machine learning in the field of atmospheric science, I have developed a training method for predicting cluster energetics of newly characterized nitrogen-based brown …
Application Of Titrations For Verification Of Small Molecule Interaction In Relation To Amidoximated Fibers For Uranium Extraction From Seawater, Kc Michael Mote
Application Of Titrations For Verification Of Small Molecule Interaction In Relation To Amidoximated Fibers For Uranium Extraction From Seawater, Kc Michael Mote
Masters Theses
Nuclear energy is a promising substitute for fossil fuels due to possessing low carbon emissions and providing scalable base-load power. However, one major drawback of using nuclear fuel as an energy source is that it needs a steady source of uranium. While the most economical method of obtaining uranium is through conventional terrestrial mining of the ore uranite, mining uranium ores is both harmful to the environment and limited by the terrestrial uranium supply, which is estimated at only 100 more years. However, more than 1000× more uranium is dissolved in seawater than is reasonably inferred and assured in terrestrial …
Characterization Of Uranium, Lead, And Rare Earth Element Pollution In Natural Soils And Sediments, Hope Rasmussen
Characterization Of Uranium, Lead, And Rare Earth Element Pollution In Natural Soils And Sediments, Hope Rasmussen
Civil and Environmental Engineering Theses and Dissertations
Heavy metals in the environment add to the global burden of pollution, negatively impacting public health and ecosystem resilience. This study included projects regarding uranium (U), lead (Pb), and rare earth elements (REE) in natural samples, due to their known toxicity, ubiquity, and relevance in context to recent pollution trends. The first project focused on testing the potential of using a hydroxyapatite product as a remediation solution for U-contaminated groundwater and soil at an EPA Superfund site. The results showed that the U was sequestered in a highly crystalline mineral form within the solids, guiding the EPA to specify the …
The Effect Of Amino Acids And Molar Peroxide Ratio On The Oxidation Of 2,4 Dinitroanisole In An Ultraviolet Light Emitting Diode/H2O2 Advanced Oxidation Process, Jeffry P. Hart
Theses and Dissertations
2,4 Dinitroanisole (DNAN) is an organic insensitive munition that is a likely candidate to replace trinitrotoluene (TNT) for a variety of purposes. Advanced Oxidation Processes (AOPs) are a promising method that have the potential to reduce a variety of persistent chemicals, however, the performance of these systems may be degraded by co-contaminants in the influent. In this contribution, DNAN, with casamino acids as a co-contaminant, was oxidized with Ultraviolet (UV) Light Emitting Diodes (LEDs) with hydrogen peroxide (H2O2) in an AOP in a laboratory. The UV/ H2O2 AOP was capable of degrading DNAN …
Coastal Watershed Monitoring And Management: Geomorphology, Geochemistry, And Hydrologic Modeling Of Los Peñasquitos Creek, Ca, Ravleen Khalsa-Basra
Coastal Watershed Monitoring And Management: Geomorphology, Geochemistry, And Hydrologic Modeling Of Los Peñasquitos Creek, Ca, Ravleen Khalsa-Basra
Theses
Rivers in semi-arid climates are directly influenced by local geographic and hydrologic conditions and impacted by modifications to hydrology via urbanization. Changes can influence erosion, morphology, habitat sustainability, and watershed health. In highly urbanized southern California coastal regions, these rare open spaces provide vital ecosystem services. Los Peñasquitos Creek in San Diego County is one such watershed. Using stream surveying and laboratory methods we quantified channel characteristics, grain size distribution, total metal concentration [M], organic carbon (%OC), and phosphate to longitudinally characterize the creek for improved management. Results identified three distinct reaches in the watershed (upper, middle, lower). Downstream, depth …
Development Of Engineered Soil Surrogates For Modeling Natural Soil Sorption Behavior, Ghada Yehia Abdalla
Development Of Engineered Soil Surrogates For Modeling Natural Soil Sorption Behavior, Ghada Yehia Abdalla
LSU Doctoral Dissertations
The land produces more than 95% of the global food supply, and with a continuously growing population, we need to optimize the use of the available agricultural land. Soil organic matter (SOM) is an essential component of soils, especially concerning their fertility and sorption behavior. The chemical composition of the SOM consists of lipids, lignin, and cellulose. However, the heterogeneous and complex nature of SOM, and real soils, makes their study challenging and introduces uncontrollable factors.
Therefore, structural mimics of natural soils with increasing complexity representing the real soil functionality were synthesized and evaluated for bulk properties related to their …
Photoluminescence Properties Of Polycyclic Aromatic Sulfur Heterocycles And Their Sorption And Desorption Onto Microplastics., Sadia Arif
Electronic Theses and Dissertations, 2020-
Polycyclic aromatic sulfur heterocycles (PASHs) are sulfur analogues of polycyclic aromatic hydrocarbons (PAHs) commonly found in environmental samples exposed to oil contamination. The determination of PASHs in complex samples is far more difficult than PAHs because of the sulfur atom in the heterocyclic ring, which increases the total number of possible isomeric compounds. Since their toxicological properties vary considerably from isomer to isomer, the unambiguous determination of specific isomers in environmental samples is crucial for ecotoxicological purposes and human safety. GC-MS has been the primary analytical technique for the determination of PASHs in environmental samples. Unfortunately, as the number of …
Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright
Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright
Theses
Anomalously elevated arsenic concentrations occur at an abandoned artisanal mine site in an open space recreational park in urban San Diego County, California. Although mining at the site ceased 100 years ago little to no remediation efforts took place leaving shafts, adits, waste piles and derelict infrastructure accessible by inquisitive hikers and adventurers frequenting Black Mountain Open Space Park. This study evaluates the geochemical mechanisms of As transport downgradient from the mine and examines the contribution of both climate and urbanization on the restriction of As mobility. Sediment As concentrations reach 2,320 mg/kg (483 times background crustal concentrations; n=73) along …
Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah
Valorization Of Xylan In Agroforestry Waste Streams, Harrison Appiah
Graduate Theses, Dissertations, and Problem Reports
Valorization of Xylan in Agroforestry Waste Streams.
Harrison Appiah
Microwave-assisted deep eutectic solvent and gamma-valerolactone metallic chloride catalyzed conversion of xylan to furfural were investigated using a 2x3 factorial experimental design at two levels of percent microwave power, reaction time, and catalyst concentration. The levels of each factor studied were (20%, 60% microwave power, 2, 4 minutes, and 10, 20mg) respectively. The effect of three metallic chloride catalysts (LiCl, FeCl3.6H20, CuCl2) on the conversion of xylan to furfural was also investigated. The gamma-valerolactone-ferric chloride sent system exhibited the highest mean yield of furfural (56.50%). The next highest furfural yield of …
An Experimental Study Of Evaporites On Titan: Implications For Lake Composition And Future Missions, Ellen Czaplinski
An Experimental Study Of Evaporites On Titan: Implications For Lake Composition And Future Missions, Ellen Czaplinski
Graduate Theses and Dissertations
Titan is the only other planetary body in the solar system with liquid on the surface. With a surface temperature and pressure of 89 – 94 K and 1.5 bar (N2), respectively, Titan’s lakes are comprised of liquid hydrocarbons, predominantly methane and ethane. Over time, Titan’s lakes may evaporate, leaving behind residual deposits (evaporites). The evaporation processes and composition of the evaporites is poorly understood. I address these outstanding questions by experimentally investigating the physical and spectral properties of evaporites at Titan surface conditions using an experimental chamber.
Chapter 1 addresses the formation of ethylene evaporites. Ethylene evaporites form more …