Trapped Ion Mobility Spectrometry Coupled To Fourier Transform Ion Cyclotron Resonance Mass Spectrometry For The Analysis Of Complex Mixtures., 2017 Florida International University
Trapped Ion Mobility Spectrometry Coupled To Fourier Transform Ion Cyclotron Resonance Mass Spectrometry For The Analysis Of Complex Mixtures., Paolo Benigni
FIU Electronic Theses and Dissertations
Analytical Characterization of complex mixtures, such as crude oil, environmental samples, and biological mixtures, is challenging because of the large diversity of molecular components. Mass spectrometry based techniques are among the most powerful tools for the separation of molecules based on their molecular composition, and the coupling of ion mobility spectrometry has enabled the separation and structural elucidation using the tridimensional structure of the molecule. The present work expands the ability of analytical chemists by furthering the development of IMS-MS instrumentation by coupling Trapped Ion Mobility Spectrometry to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (TIMS-FT-ICR MS). The TIMS-FT-ICR MS ...
Numerical Simulations Of The Biogeochemical Impact Of Atmospheric Nitrogen Deposition On Surface Waters Of The Western North Atlantic, 2017 Virginia Institute of Marine Science
Numerical Simulations Of The Biogeochemical Impact Of Atmospheric Nitrogen Deposition On Surface Waters Of The Western North Atlantic, Pierre St-Laurent, Marjorie A.M. Friedrichs
The impacts of atmospheric nitrogen deposition on the chlorophyll and nitrogen dynamics of surface waters in the western North Atlantic (25-45N, 65-80W) were examined with a biogeochemical ocean model forced with a regional atmospheric chemistry model. The model simulations cover the period 2004 to 2008 and are fully described in the following reference: St-Laurent, P., et al., Impacts of atmospheric nitrogen deposition on surface waters of the western North Atlantic mitigated by multiple feedbacks, J. Geophys. Res. Oceans, vol.122, doi:10.1002/2017jc013072.
Differential Uptake Of Gold Nanoparticles By 2 Species Of Tadpole, The Wood Frog (Lithobates Sylvaticus) And The Bullfrog (Lithobates Catesbeianus), Lucas B. Thompson, Gerardo L.F. Carfagno, Kurt Andresen, Andrea J. Sitton, Taylor B. Bury, Laura L. Lee, Kevin T. Lerner, Peter P. Fong
Biology Faculty Publications
Engineered nanoparticles are aquatic contaminants of emerging concern that exert ecotoxicological effects on a wide variety of organisms. We exposed cetyltrimethylammonium bromide–capped spherical gold nanoparticles to wood frog and bullfrog tadpoles with conspecifics and in combination with the other species continuously for 21 d, then measured uptake and localization of gold. Wood frog tadpoles alone and in combination with bullfrog tadpoles took up significantly more gold than bullfrogs. Bullfrog tadpoles in combination with wood frogs took up significantly more gold than controls. The rank order of weight-normalized gold uptake was wood frogs in combination > wood frogs alone > bullfrogs in ...
The Effect Of Hydrogen Bonding In Enhancing The Ionic Affinities Of Immobilized Monoprotic Phosphate Ligands, Spiro D. Alexandratos, Xiaoping Liu
Publications and Research
Environmental remediation requires ion-selective polymers that operate under a wide range of solution conditions. In one example, removal of trivalent and divalent metal ions from waste streams resulting from mining operations before they enter the environment requires treatment at acidic pH. The monoethyl ester phosphate ligands developed in this report operate from acidic solutions. They have been prepared on polystyrene-bound ethylene glycol, glycerol, and pentaerythritol, and it is found that intra-ligand hydrogen bonding affects their metal ion affinities. The affinity for a set of trivalent (Fe(III), Al(III), La(III), and Lu(III)) and divalent (Pb(II), Cd(II ...
Beyond “Inert” Ideas To Teaching General Chemistry From Rich Contexts: Visualizing The Chemistry Of Climate Change (Vc3), Peter G. Mahaffy, Thomas A. Holme, Leah Martin-Visscher, Brian E. Martin, Ashley Versprille, Mary Kirchhoff, Lallie Mckenzie, Marcy Towns
As one approach to moving beyond transmitting “inert” ideas to chemistry students, we use the term “teaching from rich contexts” to describe implementations of case studies or context-based learning based on systems thinking that provide deep and rich opportunities for learning crosscutting concepts through contexts. This approach nurtures the use of higher-order cognitive skills to connect concepts and apply the knowledge gained to new contexts. We describe the approach used to design a set of resources that model how rich contexts can be used to facilitate learning of general chemistry topics. The Visualizing the Chemistry of Climate Change (VC3) initiative ...
Mobility Characteristics Of Azithromycin In Soil, 2017 Purdue University
Mobility Characteristics Of Azithromycin In Soil, Ryan Minter, Jihyun Kim, Linda Lee
The Summer Undergraduate Research Fellowship (SURF) Symposium
The presence of pharmaceutical and personal care products (PPCPs) in the environment has become a widespread problem in recent decades. Azithromycin, a macrolide antibiotic commonly prescribed for infections in humans, has been detected in waste treatment plant discharge and surface waters across the world. Data on the mobility characteristics of azithromycin in soil is scarce, and further studies must be performed to explore the potential for azithromycin leaching to groundwater or becoming available for plant uptake. In this study, azithromycin sorption isotherms were measured on eight soils varying in pH, organic carbon content, and clay content. Soil was equilibrated with ...
Geochemical Fractionation, Speciation, And Bioavailability Of Heavy Metals In Stream Sediments In Aurora, Mo, 2017 Missouri State University
Geochemical Fractionation, Speciation, And Bioavailability Of Heavy Metals In Stream Sediments In Aurora, Mo, Miles Pearson
MSU Graduate Theses
Stream sediments from Chat Creek in Aurora, MO, part of the former Tristate Mining District, were digested via a sequential extraction procedure modeled after the Tessier method. Prior sampling had shown elevated levels of zinc, lead, and cadmium in sediments located near former chat piles. Metals in sediments were divided into four geochemical fractions: 1) easily exchangeable, 2) carbonate-bound, 3) iron-manganese oxides-bound, and 4) organic matter-bound. The distribution of the metals within these fractions can help predict the bioavailability and speciation of said metals. The majority of metals were contained in the third and to a lesser extent the fourth ...
Estimation Of Bubble-Mediated Air–Sea Gas Exchange From Concurrent Dms And Co2 Transfer Velocities At Intermediate–High Wind Speeds, 2017 Plymouth Marine Laboratory
Estimation Of Bubble-Mediated Air–Sea Gas Exchange From Concurrent Dms And Co2 Transfer Velocities At Intermediate–High Wind Speeds, Thomas G. Bell, Sebastian Landwehr, Scott D. Miller, Warren J. De Bruyn, Adrian H. Callaghan, Brian Scanlon, Brian Ward, Mingxi Yang, Eric S. Saltzman
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Simultaneous air–sea fluxes and concentration differences of dimethylsulfide (DMS) and carbon dioxide (CO2/ were measured during a summertime North Atlantic cruise in 2011. This data set reveals significant differences between the gas transfer velocities of these two gases (1kw/ over a range of wind speeds up to 21ms1. These differences occur at and above the approximate wind speed threshold when waves begin breaking. Whitecap fraction (a proxy for bubbles) was also measured and has a positive relationship with 1kw, consistent with enhanced bubble-mediated transfer of the less soluble CO2 relative to that of the more soluble DMS. However ...
Linking Organic Matter Dynamics To Management, Restoration, And Climate In The Florida Everglades, 2017 Florida International University
Linking Organic Matter Dynamics To Management, Restoration, And Climate In The Florida Everglades, Peter Regier
FIU Electronic Theses and Dissertations
The Florida Everglades is a massive and highly managed subtropical wetland ecosystem, strongly influenced by anthropogenic control of freshwater distribution and highly susceptible to a changing climate, including rising sea-level and changes in temperature and rainfall. Shifting hydrologic regimes impact ecosystem function and biogeochemistry, which in turn control the sources, fate, and transport of organic matter. As a master environmental variable, it is essential to understand how organic matter dynamics will respond to changes in the balance between freshwater and saltwater associated with landscape-scale Everglades restoration efforts and climate change. The research comprising this dissertation improves current understanding of the ...
Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, 2017 University of New Mexico
Comprehensive Silica Removal With Ferric Compounds For Industrial Wastewater Reuse, Ehren D. Baca
Civil Engineering ETDs
Cooling towers, integrated circuit (IC) manufacture and reverse osmosis (RO) generate copious amounts of wastewater high in colloidal and reactive silica inhibiting on-site or synergistic reuse. Silica present in cooling water can reach solubility limits via evaporation and form impervious scale on heat transfer surfaces that decreases efficiency. When water is treated by RO operating at high rejection, silica forms difficult-to-remove scale on the membrane feed side in the form of glassy patches and communities of aggregate particles, inhibiting aspirations for zero liquid discharge. Current methods for silica scale mitigation include abundant dosing with chemical antiscalents or complex operating schemes ...
Evaluation Of A Filtration Sorbent For Remediation Of Arsenic In Groundwater, 2017 California State University - San Bernardino
Evaluation Of A Filtration Sorbent For Remediation Of Arsenic In Groundwater, Clement Do
Electronic Theses, Projects, and Dissertations
A commercially available product, PURA PhosLock, was identified and evaluated for use as a sorbent to remove dissolved arsenic (As) from drinking water. Although marketed as a product to remove phosphate in aquaria, it is composed of iron oxide hydroxide (i.e., FeO(OH)), which is also known to adsorb dissolved As species from water. Arsenic was measured using standard methods and Graphite Furnace Atomic Absorption Spectroscopy. A first rough filtration test was performed to see if the PhosLock adsorbed As well. About 50 g of PhosLock was used to filter 10 L of tap water containing 100 ppb As ...
Depletion Of Ozone And Reservoir Species Of Chlorine And Nitrogen Oxide In The Lower Antarctic Polar Vortex Measured From Aircraft, T. Jurkat, C. Voigt, S. Kaufmann, J.-U. Grooß, H. Ziereis, A. Dörnbrack, P. Hoor, H. Bozem, A. Engel, H. Bönisch, P. F. Bernath
Chemistry & Biochemistry Faculty Publications
Novel airborne in situ measurements of inorganic chlorine, nitrogen oxide species, and ozone were performed inside the lower Antarctic polar vortex and at its edge in September 2012. We focus on one flight during the Transport and Composition of the LMS/Earth System Model Validation (TACTS/ESMVal) campaign with the German research aircraft HALO (High-Altitude LOng range research aircraft), reaching latitudes of 65°S and potential temperatures up to 405 K. Using the early winter correlations of reactive trace gases with N2O from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), we find high depletion of chlorine reservoir gases ...
Iron Isotope Fractionation During Fe(Ii) Oxidation Mediated By The Oxygen-Producing Marine Cyanobacterium Synechococcus Pcc 7002, Elizabeth S. Swanner, Timm Bayer, Wenfang Wu, Likai Hao, Martin Obst, Anneli Sundman, James Martin Byrne, F. M. Michel, I. C. Kleinhanns, A. Klapper, R. Schoenberg
Geological and Atmospheric Sciences Publications
In this study, we couple iron isotope analysis to microscopic and mineralogical investigation of iron speciation during circumneutral Fe(II) oxidation and Fe(III) precipitation with photosynthetically produced oxygen. In the presence of the cyanobacterium Synechococcus PCC 7002, aqueous Fe(II) (Fe(II)aq) is oxidized and precipitated as amorphous Fe(III) oxyhydroxide minerals (iron precipitates, Feppt), with distinct isotopic fractionation (ε56Fe) values determined from fitting the δ56Fe(II)aq (1.79‰ and 2.15‰) and the δ56Feppt (2.44‰ and 2.98‰) data trends from two replicate experiments. Additional Fe(II) and Fe(III) phases were detected using microscopy ...
Pine Needle Pyrolysis: Bio-Waste Into Biofuel, 2017 Dominican University of California
Pine Needle Pyrolysis: Bio-Waste Into Biofuel, Alexandra Fuentes
Honors Theses and Capstone Projects
This project explores the alternate uses of biomass. In particular it focuses on pine needles as a source for biofuels. Pine needles are of interest because in certain Mountain communities they are collected and removed from residential properties. By removing the pine needles, communities create a “defensible space” to prevent wild fires from destroying homes and property. These needles are often placed in regional landfills. The South Tahoe Refuse and Recycling Services alone has more than 4,340 tons of pine needles dumped at their facility annually. This large amount of biomass can be a potential energy source.
The focus ...
Phosphomolybdic Acid Catalysis Of Cellulose Hydrolysis, 2017 East Tennessee State University
Phosphomolybdic Acid Catalysis Of Cellulose Hydrolysis, Troy R. Dolmetsch
Undergraduate Honors Theses
Renewable sources such as cellulose derived biofuels are sought after in order to replace fossil fuel sources that are currently used to meet energy demands. Cellulose is a biological polymer composed of a chain of glucose molecules. Hydrolysis of cellulosic materials then has potential to serve as a source of renewable energy in the form of biofuels. The crystalline structure of cellulose is very stable, and current methods of catalyzed hydrolysis are inefficient for industrial application. This project explores the use of phosphomolybdic acid (PMA) in water to catalyze hydrolysis of microcrystalline cellulose. Temperature of hydrolysis was varied from 40 ...
Caffeine And Acetaminophen Concentration And Other Water Quality Parameters Along The Middle To Lower Bear River, 2017 Utah State University
Caffeine And Acetaminophen Concentration And Other Water Quality Parameters Along The Middle To Lower Bear River, Autumn Slade
Undergraduate Honors Capstone Projects
Various water quality parameters were measured at seven sites along the Middle to Lower Bear River and compared across the sites, to past data and to set standards in Utah and Idaho. Much of the data was comparable to past data with most state standards being met. However, nitrate was above indicator level for half of the sites, and turbidity is a problem at the last two sites. Also, chloride and unionized ammonia are at high levels by the last site. Overall, the river tended to decrease in water quality as it moved downstream, with dams like at Cutler Reservoir ...
Influence Of Histidine Residues, Ph And Charge Interactions On Membrane-Spanning Peptides, 2017 University of Arkansas, Fayetteville
Influence Of Histidine Residues, Ph And Charge Interactions On Membrane-Spanning Peptides, Ashley N. Henderson
Theses and Dissertations
Designed transmembrane peptides were employed for investigations of histidine residues within the hydrophobic environment of the lipid bilayer by means of oriented solid-state deuterium NMR spectroscopy. Using the model peptide GWALP23 sequence (GGALW(LA)6LWLAGA) as a host framework, the effects of single and double histidine mutations were explored. Replacement of leucine residue 12 to polar neutral histidine had little influence on the peptide average orientation, however under strongly acidic pH conditions in DOPC bilayers, the histidine becomes positively charged (pKa 2.5) and the GWALP23-H12 peptide exits the membrane and adopts a surface-bound orientation. Conversely, mutation of leucine 14 ...
Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., 2017 University of Louisville
Homogeneous Ligand-Centered Hydrogen Evolution And Hydrogen Oxidation : Exploiting Redox Non-Innocence To Drive Catalysis., Andrew Z. Haddad
Electronic Theses and Dissertations
Hydrogen is a promising carbon-free fuel / energy carrier and is an essential building block for many industrial and agricultural processes. Rising energy demands have ignited interest in the development of carbon-free and carbon neutral energy sources. In this context, hydrogen is an attractive candidate—being energy-dense, carbon-free—and easily accessible through a two-electron reduction of water. Accordingly, many electrochemical homogeneous catalyst systems have been studied, with a focus on understanding the mechanism of hydrogen evolution proceeding through metal-hydride intermediates. However, there has been a renaissance in hydrogen evolution reaction (HER) catalyst design, with many groups implicating ligand redox non-innocence as ...
Functionalized Silica Gel For Adsorption Of Cesium From Solution, 2017 East Tennessee State University
Functionalized Silica Gel For Adsorption Of Cesium From Solution, Kenneth Marshall Seaton Iii
Electronic Theses and Dissertations
Mesoporous silica gel containing embedded phosphotungstic acid (PTA) was synthesized by sol-gel co-condensation of tetraethyl orthosilicate with PTA in acidic media. The obtained material had high Brunauer-Emmett-Teller Theory (BET) surface area and pore volume. A characteristic band of the Keggin structure of PTA was present in its FT-IR spectrum while its X-ray diffraction patterns were absent. This proved the embedding of PTA on a sub-molecular level and not as a second phase. Acidic sites were determined by neutralization with base in aprotic solvent, followed by titration of the remaining base with an acid. The material demonstrated high adsorption capacity of ...
Development Of High Performance Gas Separation Membranes Through Intelligent Catalyst And Monomer Design, 2017 University of Tennessee, Knoxville
Development Of High Performance Gas Separation Membranes Through Intelligent Catalyst And Monomer Design, Kevin Richard Gmernicki
Polymer membranes are a valuable tool for separating components of liquid and gas mixtures. Heavily inspired by biological systems, the idea of using the intrinsic properties of polymers to perform otherwise energy-intensive tasks is attractive for applications such as water desalination, natural gas sweetening, and post-combustion carbon capture. Of particular interest to our research group, post-combustion carbon capture is a promising potential solution aimed at reducing the carbon footprint involved with production, transportation, and storage of electrical energy generation.
Every year, the United States produces close to seven billion metric tons of carbon dioxide, of which a significant portion is ...