Chemistry Commons^™

Quality Of Wheat Grains (Triticum Aestivum) Generationally Exposed To Cerium Oxide Nanoparticles (Nceo2), Oluwasegun Michael Abolade

Graduate Theses/Dissertations

The impacts of generational exposure to engineered nanomaterial on grain quality are poorly documented. This study was performed on wheat grains harvested from plants grown in soil amended with cerium oxide nanoparticles (nCeO₂) at the 2^nd and 3^rd generations. Third generation experiment was performed at low and high nitrogen (N) soil levels. The goal was to investigate changes in grain fatty acid and elemental contents due to parental exposure (C₁ vs T₁ in 2^nd generation, C₁C₂ vs T₁T₂ in 3^rd generation) or current generation …

The Development Of An Integrated Simulation Model On Understandings On The Interaction Between Electromagnetic Waves And Nanoparticles, Xiaojin Wang

Masters Theses & Specialist Projects

To investigate the interaction between nanoparticles and electromagnetic waves, a numerical simulation model based on FEM was built in this thesis. Numerical simulation is an important auxiliary research method besides experiments. The optical properties of nanoparticles consist of scattering, absorption, and extinction, and in the case of nanoparticle suspension, the transmission is also involved. This thesis addressed two typical applications based on the established model, one was regarding the nanofluids for solar energy harvesting, and the other was regarding the optical properties of atmospheric soot. In the case of the nanofluids solar energy harvesting, the established model provided a convenient …

A Simple And Effective Way To Overcome Carbon Monoxide Poisoning Of Platinum Surfaces In Direct Formic Acid Fuel Cells, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Sohair A. Darwish Ms

Chemical Engineering

A glassy carbon (GC) electrode modified with multi-walled carbon nanotubes (MWCNTs) and platinum nanoparticles (PtNPs), Pt/MWCNTs-GC, has been introduced for formic acid electro-oxidation (FAO). A similar loading of PtNPs has been conserved for a proper comparison between the Pt/MWCNTs-GC and the unmodified Pt/GC electrodes. The modification with MWCNTs could enhance the loading of PtNPs onto the GC electrode in a way that minimizes its agglomeration and increases its dispersion in the CNTs network. This not only increases the surface area exposed to the reaction but also interrupts the contiguity of the Pt active sites minimizing the adsorption of the poisoning …

A Promising Modification Of Pt Surfaces With Cnts For Decreasing Poisoning Impact In Direct Methanol Fuel Cells, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Aya A. Khalifa Ms.

Chemical Engineering

Direct methanol fuel cells (DMFCs) are clean energy sources that have many applications due to the high energy density of methanol as a fuel. However, this type of fuel cells (FCs) has limitations that are preventing it from being commercialized. One such limitation is the adsorption of intermediates such as CO into the surface of the Platinum (Pt) catalyst during methanol oxidation (MO) which deactivates its active sites, where the reaction is taking place, and leads to poisoning of the electrode over the long term. In this study, multi-walled carbon nanotubes (MWCNTs) have been introduced to the Pt-modified glassy carbon …

The Spectroscopic And Computational Exploration Of Sulfur Hydrogen Bonding, Andrew Yoonkeun Lee

Honors Projects

Hydrogen bonds are a subset of non-covalent interactions that occur between X-H — Y, in which X and Y are the very electronegative atoms. In our research, we examine the more unconventional hydrogen bond-like interactions of thiol (SH) containing molecules using vapor-phase infrared (IR) spectroscopy and ab initio computational chemistry. When the SH hydrogen bond donor complexes to a hydrogen bond acceptor, a red shift of the SH stretching mode emerges. An anharmonic oscillator local mode model is applied to the ethanethiol-trimethylamine dimer, and we determine that any IR evidence of dimerization in our experiment is likely obscured by the …

Crystal Structure Of Zymonic Acid And A Redetermination Of Its Precursor, Pyruvic Acid, Dominik Heger, Alexis J. Eugene, Sean R. Parkin, Marcelo I. Guzman

Chemistry Faculty Publications

The structure of zymonic acid (systematic name: 4-hy­droxy-2-methyl-5-oxo-2,5-di­hydro­furan-2-carb­oxy­lic acid), C₆H₆O₅, which had previously eluded crystallographic determination, is presented here for the first time. It forms by intra­molecular condensation of parapyruvic acid, which is the product of aldol condensation of pyruvic acid. A redetermination of the crystal structure of pyruvic acid (systematic name: 2-oxo­propanoic acid), C₃H₄O₃, at low temperature (90 K) and with increased precision, is also presented [for the previous structure, see: Harata et al. (1977). Acta Cryst. B33, 210–212]. In zymonic acid, the hy­droxy­lactone ring …

The Investigation Of Methylidyne Radical (Ch) Reactions With Furan, 2-Methylfuran, And 2,5-Dimethlyfuran And The Photoionization And Photodissociation Of Valeric Acid, Erica Carrasco

Master's Theses

This thesis presents the combustion study of three furanic compounds using synchrotron radiation coupled with multiplexed photoionization mass spectrometry at 298 K. The experiments were performed at the Chemical Dynamics Beamline 9.0.2 at the Advanced Light Source of the Lawrence Berkeley National Laboratory. The reactions of the three furanic compounds with methylidyne (CH) radicals were analyzed based on their photoionization spectra and kinetic profiles.

Additionally, the unimolecular dissociation of valeric acid was also studied and presented in this work using the double imaging photoelectron photoion spectrometry (i2PEPICO) coupled with synchrotron radiation from the VUV beamline. The experiments were carried out …

Elemental And Oxidized Mercury In Ambient Air At Rocky Flats, Colorado, Seth Lyman, Lynne Gratz

Browse all Datasets

This is a dataset of elemental and oxidized mercury in the ambient atmosphere at latitude 39.912799 and longitude -105.188587. This is the locations of the Rocky Flats North air quality monitoring station, operated by the Colorado Department of Public Health and Environment. We collected these measurements using a dual-channel atmospheric mercury speciation instrument.

Development Of Granulated Adsorbent For Clean-Up Of Water Contaminated By Cesium, Esther Alorkpa

Electronic Theses and Dissertations

A study was conducted on sol-gel synthesis of an adsorbent (phosphotungstic acid embedded in silica gel, H-PTA/SiO­₂) of radioactive cesium. A novelty of this work is covalent bonding of PTA to the surface of solid support that prevents leaching from the surface of the material. The sample was granulated with a binder, aluminium oxide (γ-Al₂O₃). Solid-state NMR and FT-IR spectroscopy were used to confirm the presence of Keggin units of PTA in the bound materials. Thermal analysis of H-PTA/SiO­₂ - γ-Al₂O₃ (50 %) showed that the water content in the …

The Effects Of Climate Change And Forest Disturbances On Terpene Production Of White Pine (Pinus Strobus) And Red Pine (Pinus Resinosa) In Northern Michigan, Troy Dehagen

Honors Theses

The secondary impacts that climate change may have on the interactions between forests and the atmosphere through forest disturbances is of increasing interest as the climate continues to change. Anthropogenic climate change, which is a direct result of coal and fossil fuel emissions, is likely to impact forest ecology through increased temperatures and extreme precipitation events, thus increasing the frequency and severity of climate-induced forest disturbances. Forest disturbances may have a secondary impact on the production and emission of biogenic volatile organic compounds (BVOC) within forests. In the presence of oxides of nitrogen (NO_x) produced from fossil fuel …

Elemental Analysis Of Legacy Sediments At College Lake, Amelia Dalton

Student Scholar Showcase

College Lake is a large reservoir located on the campus of the University of Lynchburg. College Lake’s ecosystem has degraded over the years due to the buildup of sediment, nutrients, and raw sewage. Increased urbanization in the area has also most likely contributed to the contaminants present within the system. Because of flooding issues during the summer of 2018, Lynchburg CIty officials drained College Lake, which caused sediment to be released downstream. To better understand the transport of heavy metals in the sediments released from College Lake, sediment core samples were taken from College Lake, Hollins Mill Park, and Sandusky …

Fluoride Removal From Water Using A 3d Printed Calcium Carbonate Filter, Sophia Bakar, David Kahler, Benjamin S. Goldschmidt

Undergraduate Research and Scholarship Symposium

Groundwater containing high concentrations of fluoride is the most common source of drinking water in rural areas in parts of east Africa, India, and China. The elevated levels of fluoride cause skeletal and dental fluorosis, which is the weakening and decay of bone structures due to the leeching of calcium from the body as calcium and fluoride bond by the process of adsorption. Over 150 million people are suffering from some form of fluorosis due to the consumption of groundwater. Calcium carbonate has been demonstrated to influence fluoride removal in several forms. To make fluoride removal a cost-effective and user-friendly …

Growth, Lipid Production And Biodiesel Potential Of Chromulina Freiburgensis Dofl., An Acidophilic Chrysophyte Isolated From Berkeley Pit Lake, June E. Mohler Mitman

Graduate Theses & Non-Theses

Microalgae remain a promising, but underdeveloped source of lipids for sustainable biodiesel. Some of the obstacles to cost-effective commercial-scale production have been culture contamination and expensive harvest methods. A chrysophyte isolated from Berkeley Pit Lake and identified as Chromulina freiburgensis, was found to grow rapidly in a pH 2.5 liquid medium and to amass numerous intracellular lipid bodies. This research addresses the scarcity of published knowledge on the topic of chrysophyte species as potential lipid sources for biodiesel. It investigates how growth phase, culture conditions, and harvest timing influence the quantity and composition of lipids produced by this alga. …

The Effects Of Reactant Concentration And Air Flow Rate In The Consumption Of Dissolved O2 During The Photochemistry Of Aqueous Pyruvic Acid, Alexis J. Eugene, Marcelo I. Guzman

Chemistry Faculty Publications

The sunlight photochemistry of the organic chromophore pyruvic acid (PA) in water generates ketyl and acetyl radicals that contribute to the production and processing of atmospheric aerosols. The photochemical mechanism is highly sensitive to dissolved oxygen content, [O₂(aq)], among other environmental conditions. Thus, herein we investigate the photolysis (λ ≥ 305 nm) of 10–200 mM PA at pH 1.0 in water covering the relevant range 0 ≤ [O₂(aq)] ≤ 1.3 mM. The rapid consumption of dissolved oxygen by the intermediate photolytic radicals is monitored in real time with a dissolved oxygen electrode. …

Purification And Characterization Of A Nonspecific Lipid Transfer Protein 1 (Nsltp1) From Ajwain (Trachyspermum Ammi) Seeds, Meshal Nazeer, Humera Waheed, Maria Saeed, Saman Yousuf Ali, M. Iqbal Choudhary, Zaheer Ul-Haq, Aftab Ahmed

Pharmacy Faculty Articles and Research

Ajwain (Trachyspermum ammi) belongs to the family Umbelliferae, is commonly used in traditional, and folk medicine due to its carminative, stimulant, antiseptic, diuretic, antihypertensive, and hepatoprotective activities. Non-specific lipid transfer proteins (nsLTPs) reported from various plants are known to be involved in transferring lipids between membranes and in plants defense response. Here, we describe the complete primary structure of a monomeric non-specific lipid transfer protein 1 (nsLTP1), with molecular weight of 9.66 kDa, from ajwain seeds. The nsLTP1 has been purified by combination of chromatographic techniques, and further characterized by mass spectrometry, and Edman degradation. The ajwain nsLTP1 …

Evaluating Seasonal Nutrient Fluxes In Emerging And Eroding Wetlands Of The Louisiana Delta Plain, Kiran Upreti

LSU Doctoral Dissertations

Deltaic wetlands can ameliorate high NO₃^- loads via denitrification, a dominant NO₃^- reduction pathway in inland and coastal habitats. Dissimilatory Nitrate Reduction to Ammonia (DNRA), in contrast to denitrification, conserves N within the system and has been found to be favored over denitrification with increase in salinity and temperature. There are no studies in the Louisiana Deltaic plain with simultaneous estimation of denitrification and DNRA. Increased P availability has been shown to increase denitrification so it is essential to understand P biogeochemistry when studying N cycle. Here, we evaluated net denitrification using N₂:Ar and …

Lake Sediment Analysis At Heron Haven Nature Center, Erik Lato

UNO Student Research and Creative Activity Fair

Understanding the chemical composition of a wetland sanctuary lakebed can help us understand how recent developments may have changed the chemical composition. Due to recent dredging by the U.S. Army Corps of Engineers and previous research on water composition at Heron Haven, the goal of this project was to determine the chemical composition as a function of sediment depth. The concentration of seven different metals and nutrients were analyzed in terms of depth. The aluminum, iron, and phosphate concentrations had no real discernible concentration change as a function of depth. There is some hint of a steady increase of manganese …

Seasonal Origins Of Soil Water Used By Trees, Scott T. Allen, James W. Kirchner, Sabine Braun, Rolf T. W. Siegwolf, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Rain recharges soil water storages and either percolates downward into aquifers and streams or is returned to the atmosphere through evapotranspiration. Although it is commonly assumed that summer rainfall recharges plant-available water during the growing season, the seasonal origins of water used by plants have not been systematically explored. We characterize the seasonal origins of waters in soils and trees by comparing their midsummer isotopic signatures (δ2H) to seasonal isotopic cycles in precipitation, using a new seasonal origin index. Across 182 Swiss forest sites, xylem water isotopic signatures show that summer rain was not the predominant water source …

Viscosities, Diffusion Coefficients, And Mixing Times Of Intrinsic Fluorescent Organic Molecules In Brown Limonene Secondary Organic Aerosol And Tests Of The Stokes–Einstein Equation, Dagny A. Ullmann, Mallory L. Hinks, Adrian M. Maclean, Christopher Butenhoff, James W. Grayson, Kelley Barsanti, Jose L. Jimenez, Sergey A. Nizkorodov, Saeid Kamal, Allan K. Bertram

Physics Faculty Publications and Presentations

Viscosities and diffusion rates of organics within secondary organic aerosol (SOA) remain uncertain. Using the bead-mobility technique, we measured viscosities as a function of water activity (a_w) of SOA generated by the ozonolysis of limonene followed by browning by exposure to NH₃ (referred to as brown limonene SOA or brown LSOA). These measurements together with viscosity measurements reported in the literature show that the viscosity of brown LSOA increases by 3–5 orders of magnitude as the aw decreases from 0.9 to approximately 0.05. In addition, we measured diffusion coefficients of intrinsic fluorescent organic molecules within brown …

Potential Degradation Of Hexabromocyclododecane (Hbcdd) In Sediments: Stereoisomer Specific Reaction Of Hbcdd With Reduced Sulfur Species Or Fe(Ii) Bound To Iron Oxides, Xianmiao Zhang

Dissertations, Theses, and Capstone Projects

The individual degradation rates of the three dominant stereoisomers (alpha, beta, gamma) of hexabromocyclododecane (HBCDD) with bisulfide and polysulfides were investigated at pH 9-10 in methanol/water solutions at two different temperatures (25 °C and 40 °C). alpha-HBCDD reacts significantly slower than beta-HBCDD and gamma-HBCDD. It was also observed that the reaction of HBCDD with polysulfides is faster than with bisulfide. For the reaction of HBCDD with bisulfide, the experiments were performed in 20% water/80% methanol, 50% water/50% methanol and 80% water/20% methanol at 40 °C. It was determined that the solvent polarity affects the reaction and the second-order rate constants …

Carbohydrate Polymers As Controlled Release Devices For Pesticides, Soma Chakraborty, Maria Cleofe Neri-Badang

Chemistry Faculty Publications

Controlled release technology addresses problems associated with excessive use of toxic agricultural chemicals. This paper reviews the studies on the use of carbohydrate polymers as controlled release matrices for pesticides. Alginates, starch and its derivatives, chitosan, carboxymethylcellulose and ethylcellulose are some of the natural polymers discussed in this review. The advantages and disadvantages of these polymeric systems as well as the factors that affect pesticide release are presented. A discussion on the polymers’ encapsulation efficiency and release profile is also included, which will aid future researchers in identifying the suitable formulation for controlled release of pesticides. Combination of two polymers, …

Effect Of Dissolved Salts On The Physiochemical Properties Of Deep Eutectic Solvents, Eleanor Haeska, Megan Radtke

The Journal of Undergraduate Research

Green chemistry seeks to make chemical procedures safer, improve reaction efficiency, and utilize environmentally safe reagents. Deep eutectic solvents (DES) have recently become of great interest due to their eco-friendly nature and functionality as solvent for various chemical processes. One key characteristic of DES is their conductive nature and depressed melting point. This project sought to determine the effect of the addition of aqueous solutions of halides on the conductivity of two selected types of DES. Also assessed were the polarity and viscosity of the DES. It can be concluded that aqueous halides had no measureable effect on the conductivity …

Increased Perchlorate In The Environment Following The 1600 C.E. Huaynaputina Volcanic Eruption, Joseph Gibson, Amanda Shea

The Journal of Undergraduate Research

Perchlorate is an environmental contaminant that can have adverse health effects on humans. Although our knowledge about how natural perchlorate is formed is very limited, volcanic eruptions are believed to play an important role. An ice core obtained from Summit Station, Greenland was used to study the effects of the Huaynaputina eruption on the amount of perchlorate in the environment. The section of ice core sampled was determined to span the years 1594 through 1610. The results indicate that the Huaynaputina eruption caused a temporary but significant increase in the amount of perchlorate in the atmosphere.

Toward The Impact Of Particulate Matter On Human Health: Evaluation Of Fluorescent Environmentally Persistent Free Radical (Epfr) Surrogates, Ansonia Badgett

LSU Doctoral Dissertations

Environmentally persistent free radicals (EPFRs)—a newly discovered pollutant associated with particulate matter (PM)—form during combustion and thermal processes, such as the incineration of hazardous waste. Various chlorine- and hydroxy-substituted benzenes chemisorb on the surface of metal oxides (e.g., NiO, CuO, and Fe₂O₃) and then form EPFRs, stabilized radical species, as the result of the transfer of electrons between the adsorbate and the metal ion of the metal oxide. Previous studies have shown direct correlations between ultra-fine (d < 0.1 mm) particulate matter (PM_0.1) exposure and adverse pulmonary health effects. PM_0.1 has the potential …

Facile Synthesis Of A Tailored-Designed Au/Pt Nanoanode For Enhanced Formic Acid, Methanol, And Ethylene Glycol Electrooxidation, Yaser M. Asal Mr., Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof

Chemical Engineering

The recent revolution in nanoscience and global energy demand have motivated research in liquid fuel cells (LFCs) due to their enhanced efficiency, moving flexibility, and reduced contamination. In line with this advancement, a glassy carbon (GC) electrode was modified with platinum (PtNPs) and gold (AuNPs) nanoparticles to fabricate a nanosized anode for formic acid, methanol, and ethylene glycol electrooxidation (abbreviated, respectively, to FAO, MO, and EGO), of the key anodic reactions of LFCs. The deposition sequence of the catalyst’s layers was important where the Au/Pt/GC electrode (in which PtNPs were directly deposited onto the GC surface followed by AuNPs—surface coverage …

Characterizing The Effects Of Environmental Stressors On The Photosynthetic Capacity Of Chlorella Vulgaris, Amanda Louise Smythers

Theses, Dissertations and Capstones

Chlorella vulgaris is a unicellular green algae grown throughout the world. Due to its multiple trophic modes as well as its ability to maintain high rates of growth under adverse conditions, it has been of global interest for use in ecological contamination studies, biofuel feedstock optimization, and studies of photosynthetic electron transfer. Using a wide-range of methods for physiological and photosynthetic characterization, the studies within seek to further extend the usefulness of C. vulgaris in a variety of environmentally important studies. Once the protocols were optimized specifically for this alga, they could be applied in both ecologically relevant and biodiesel …

A Promising Modification Of Pt Surfaces With Cnts For Decreasing Poisoning Impact In Direct Methanol Fuel Cells, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Aya A. Khalifa Ms.

Chemical Engineering

Direct methanol fuel cells (DMFCs) are clean energy sources that have many applications due to the high energy density of methanol as a fuel. However, this type of fuel cells (FCs) has limitations that are preventing it from being commercialized. One such limitation is the adsorption of intermediates such as CO into the surface of the Platinum (Pt) catalyst during methanol oxidation (MO) which deactivates its active sites, where the reaction is taking place, and leads to poisoning of the electrode over the long term. In this study, multi-walled carbon nanotubes (MWCNTs) have been introduced to the Pt-modified glassy carbon …

Enhanced Electro-Oxidation Of Methanol At Pt-Au Nanocatalyst For Direct Methanol Fuel Cells, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Ahmad M. Mohammad Prof

Chemical Engineering

In this investigation, a Pt-Au nanocatalyst prepared by the coelectrodeposition of Pt (PtNPs) and Au (AuNPs) nanoparticles is assembled onto a glassy carbon (GC) electrode for efficient methanol oxidation (MO). Several molar ratios between PtNPs and AuNPs have been used and the corresponding catalytic activity towards MO is tracked. The Pt1:Au1 catalyst showed the highest catalytic activity (5 times higher oxidation peak current (Ip) and a 126 mV negative shift in the onset potential (Eonset) toward MO). The catalyst’s morphology, composition and activity are investigated and the ehancement mechanism is recognized.

A Simple And Effective Way To Overcome Carbon Monoxide Poisoning Of Platinum Surfaces In Direct Formic Acid Fuel Cells, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Sohair A. Darwish Ms

Chemical Engineering

A glassy carbon (GC) electrode modified with multi-walled carbon nanotubes (MWCNTs) and platinum nanoparticles (PtNPs), Pt/MWCNTs-GC, has been introduced for formic acid electro-oxidation (FAO). A similar loading of PtNPs has been conserved for a proper comparison between the Pt/MWCNTs-GC and the unmodified Pt/GC electrodes. The modification with MWCNTs could enhance the loading of PtNPs onto the GC electrode in a way that minimizes its agglomeration and increases its dispersion in the CNTs network. This not only increases the surface area exposed to the reaction but also interrupts the contiguity of the Pt active sites minimizing the adsorption of the poisoning …

Detecting Cyanobacteria Toxins: The Human Health Impact Of An Environmental Problem, Lillian E. Naimie

Honors Theses

Cyanobacteria blooms are a growing concern in the world, as they can form a dense and sometimes toxin scum on water bodies. This paper will outline and discuss the environmental conditions that produce cyanobacteria bloom with a focus on the toxins produced by blooms and specifically the detection of these toxins through two analytical methods. Of the various toxins cyanobacteria are capable of producing, this paper will focus on microcystins and BMAA, a family of hepatotoxins and a specific neurotoxin respectively. The two analytical methods discussed are liquid chromatography coupled mass spectrometry and ELISA kit techniques. The advantages and drawbacks …