Environmental Chemistry Commons^™

Regional-Scale Simulations Of Fungal Spore Aerosols Using An Emission Parameterization Adapted To Local Measurements Of Fluorescent Biological Aerosol Particles, Matthias Hummel, Corinna Hoose, M. Gallagher, D. A. Healy, J. Alex Huffman, D. O'Connor, U. Pöschl, C. Pöhlker, N. H. Robinson, M. Schnaiter, J. R. Sodeau, M. Stengel, E. Toprak, H. Vogel

Chemistry and Biochemistry: Faculty Scholarship

Fungal spores as a prominent type of primary biological aerosol particles (PBAP) have been incorporated into the COSMO-ART (Consortium for Small-scale Modelling- Aerosols and Reactive Trace gases) regional atmospheric model. Two literature-based emission rates for fungal spores derived from fungal spore colony counts and chemical tracer measurements were used as a parameterization baseline for this study. A third, new emission parameterization for fluorescent biological aerosol particles (FBAP) was adapted to field measurements from four locations across Europe. FBAP concentrations can be regarded as a lower estimate of total PBAP concentrations. Size distributions of FBAP often show a distinct mode at …

The Micro-Orifice Uniform Deposit Impactor–Droplet Freezing Technique (Moudi-Dft) For Measuring Concentrations Of Ice Nucleating Particles As A Function Of Size: Improvements And Initial Validation, R. H. Mason, C. Chou, C. S. Mccluskey, E. J. T. Levin, C. L. Schiller, T. C. J. Hill, J. Alex Huffman, P. J. Demott, A. K. Bertram

Chemistry and Biochemistry: Faculty Scholarship

The micro-orifice uniform deposit impactor– droplet freezing technique (MOUDI-DFT) combines particle collection by inertial impaction (via the MOUDI) and a microscope-based immersion freezing apparatus (the DFT) to measure atmospheric concentrations of ice nucleating particles (INPs) as a function of size and temperature. In the first part of this study we improved upon this recently introduced technique. Using optical microscopy, we investigated the non-uniformity of MOUDI aerosol deposits at spatial resolutions of 1, 0.25 mm, and for some stages when necessary 0.10 mm. The results from these measurements show that at a spatial resolution of 1mm and less, the concentration of …

Thermal Degradation Of Amines For Co2 Capture, Quanzhen Huang

Theses and Dissertations--Chemistry

In the selection of candidates for CO₂ absorption, solvent thermal degradation has become a general concern due to the significant impact on operational cost and the intention to use thermal compression from high temperature stripping to minimize the overall process energy. In this research, the impact of flue gas contaminants on Monoethanolamine (MEA) thermal degradation was investigated at elevated temperatures consistent with those in the CO₂ stripper. Nitrite, fly ash, sulfate and thiosulfate were each added to 5.0 M MEA and the contaminant-containing MEA solutions were degraded at 125 °C, 135 °C and 145 °C. MEA degrades significantly …

Selective Solid Phase Extraction Of Uranium Using An Aminophosphonic Acid Functionalized Composite Material, Ranalda Tsosie

Graduate Student Theses, Dissertations, & Professional Papers

Uranium is an element of interest because it is an abundant source of concentrated energy. In 1948 the US offered money for uranium ore mined in the US, which created a mining boom in the southwest that included the Navajo Reservation. During the late 1960s the demand for uranium decreased and many mining operations shutdown and left behind a legacy of contamination. As a result many Navajo communities have numerous water sources that exceed established maximum contamination levels for uranium and other toxic metals. These contaminations are a direct result of abandoned Cold War uranium mines and mill waste sites …

Characterization Of Terrestrial Dissolved Organic Matter Fractionated By Ph And Polarity And Their Biological Effects On Plant Growth, Rachel L. Sleighter, Paolo Caricasole, Kristen M. Richards, Terry Hanson, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Background: Humic substances are ubiquitous in the environment, complex mixtures, and known to be beneficial to plant growth. To better understand and identify components responsible for plant growth stimulation, a terrestrial aquatic DOM sample was fractionated according to pH and polarity, obtaining acid-soluble and acid-insoluble portions, as well as acid-soluble hydrophobic and hydrophilic fractions using C18. The various fractions were characterized then evaluated for their biological effects on plant growth using bioassays with corn at two carbon rates.

Results: Approximately 43% and 57% of the carbon, and 31% and 69% of the iron, was found in the acid-insoluble and acid-soluble …

Investigation Of Interferences And Development Of Pre-Treatment Methods For Arsenic Analysis By Anodic Stripping Voltammetry, Paul Lewtas

Theses: Doctorates and Masters

Contamination of drinking water is a serious health issue in many developing countries and there is a recognised need for low cost portable systems that are capable of analysing drinking water down to low ppb levels. Anodic Stripping Voltammetry (ASV) instruments meet these requirements but suffer interferences from other species which may also be present in the sample, particularly organics, other metals and sulfides. The last of these has received surprisingly little attention in the literature, despite being a proven interferent.

This study investigates the impact of each of these interference types, as well as a number of traditional and …

Real ‐ World Vehicle Emissions Measurements (Presentation), Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Reactive Nitrogen Species Emission Trends In Three Light-/Medium-Duty United States Fleets, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

Repeated, fuel specific, emission measurements in Denver (2005/2013), Los Angeles (2008/2013) and Tulsa (2005/2013) provide long-term trends in on-road reactive nitrogen emissions from three light/medium duty U.S. fleets. Reductions in oxides of nitrogen (NO_x) emissions ranged from 21% in Denver (5.6 ± 1.3 to 4.4 ± 0.2 gNO_x/kg of fuel) to 43% in Tulsa (4.4 ± 0.3 to 2.5 ± 0.1 gNOx/kg of fuel) since 2005 while decreases in fleet ammonia (NH₃) emissions ranged from no change in Denver (0.45 ± 0.09 to 0.44 ± 0.02 gNH₃/kg of fuel) since 2005 to …

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2014, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.

Optical Characterization And Distribution Of Chromophoric Dissolved Organic Matter (Cdom) In Soil Porewater From A Salt Marsh Ecosystem, Catherine D. Clark, Paige Aiona, Jason K. Keller, Warren J. De Bruyn

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

To characterize chromophoric dissolved organic matter (CDOM) in marsh porewaters and its contribution as a carbon source, optical properties (absorbance, fluorescence indices, 3-dimensional excitation-emission matrices [EEMs]) of soil porewater and surface water were measured in a southern Californian salt marsh. Absorption coefficients and fluorescence intensities were higher in porewater than in overlying surface waters, consistent with higher CDOM concentration at depth. Humic-type peaks A and C were observed in EEMs in all samples, and peak M was observed in surface waters and shallow porewater to -5 cm depth. Fluorescence:absorbance (flu:abs) ratios and spectral slopes (S) decreased across the surface interface, …

Magnetic Nickel Nanoparticles: Synthesis, Environmental Lmplications And Potential Role As Drug Carriers, Setare Tahmasebi Nick

Dissertations

The design and synthesis of well-defined magnetic particles with nanoscale dimensions is opening new avenues in understanding their fundamental chemical and physical properties. Our work describes a novel facile procedure for the synthesis of homogenous isotropic and anisotropic magnetic nickel nanoparticles. These nanoparticles were produced using a wet-chemical process and characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), powder x-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA). Magnetic measurements were acquired using a superconducting quantum interference device (SQUID) magnetometer. While there is significant interest in using magnetic nanoparticles for biological …

Simultaneous Determination Of Multiple Actinide Elements In A Variety Of Soils Utilizing A Standardized Sequential Extraction Protocol, Sherry Alina Faye

UNLV Theses, Dissertations, Professional Papers, and Capstones

To obtain a better understanding of the mobility of actinide element contaminants in the environment, the association of the contaminants with specific host phases of soils and sediments must be investigated. This investigation is most commonly conducted using sequential extraction techniques that employ the selective dissolution of soil phases with increasingly aggressive chemical treatment. Though several sequential extraction studies exist in literature, conclusions cannot be made by direct comparison of data due to the lack of uniformity in the protocols used. This work aims to continue development of a standard sequential extraction protocol and expanding its capabilities to include the …

Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air–water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon …

The Development Of A Valid And Reliable Biogeochemistry Concept Inventory, Chris Mead

Discipline-Based Education Research Group Speaker Series

Concept inventories are a commonly used tool to measure conceptual understanding. To date, concept inventories have been published for geology, chemistry, and biology, but no instrument has been designed to measure conceptual understanding at the intersection of those fields. To fill that gap, we constructed a 32‐item biogeochemistry concept inventory (BGC‐CI). Item response theory analysis, using the Rasch model, shows the BGC‐CI is a reliable and valid tool to measure the biogeochemistry knowledge of science majors. Because biogeochemistry is an interdisciplinary field, we were concerned about the unidimensionality of the instrument. However, our analysis showed the BGC‐CI to be acceptably …

Peptide Arrays For Detecting Naphthenic Acids In Oil Sands Process Affected Water, Kamaljit Kaur, Subir Bhattacharjee, Rajesh G. Pillai, Sahar Ahmed, Sarfuddin Azmi

Pharmacy Faculty Articles and Research

Naphthenic acids (NAs) are water-soluble components of petroleum. The characterization and quantification of NAs by analytical methods have proved quite challenging, whilst the toxic effects of these water-soluble compounds on a variety of organisms adversely affecting reproduction and steroid production is becoming apparent. In this study, we report a fluorescence-based competitive binding method for rapid sensing of the presence of NAs using cellulosic peptide array strips as sensors. The peptide array was designed from sequences derived from the estrogen receptor (ER). Several of these peptides were able to detect the presence of NAs at low micromolar (∼5 mg L^{−1 …}

Correlation Of Chemical Concentration To Color, Garrett Bosse, Nathan Schrock, Ryan Longchamps, Sam Winkler

Von Braun Symposium Student Posters

No abstract provided.

Interactive Comment On “Iodine Oxide In The Global Marine Boundary Layer” By C. Prados-Roman Et Al., Marcelo I. Guzman

Chemistry Faculty Publications

No abstract provided.

Iron Sources And Dissolved-Particulate Interactions In The Seawater Of The Western Equatorial Pacific, Iron Isotope Perspectives, M. Labatut, F. Lacan, C. Pradoux, J. Chmeleff, A. Radic, J. W. Murray, F. Poitrasson, Anne M. Johansen, F. Thil

All Faculty Scholarship for the College of the Sciences

This work presents iron isotope data in the western equatorial Pacific. Marine aerosols and top core margin sediments display a slightly heavy Fe isotopic composition (δ⁵⁶Fe) of 0.33 ± 0.11‰ (2SD) and 0.14 ± 0.07‰, respectively. Samples reflecting the influence of Papua New Guinea runoff (Sepik River and Rabaul volcano water) are characterized by crustal values. In seawater, Fe is mainly supplied in the particulate form and is found with a δ⁵⁶Fe between −0.49 and 0.34 ± 0.07‰. The particulate Fe seems to be brought mainly by runoff and transported across continental shelves and slopes. …

Degradation Of Protective Glove Materials Exposed To Commercial Products: A Comparative Study Of Tensile Strength And Gravimetric Analyses, Todd B. Pelham

Electronic Theses, Projects, and Dissertations

ABSTRACT

Current glove guides attempt to assist in recommending which type of glove is appropriate for handling chemicals; however, they include information on less than 1% of the 89 million chemical products available today.

This study offers a solution by testing five durable polymer materials against 50 chemicals, using two rapid chemical degradation assessment techniques. The first technique involves gravimetric analysis of the weight change following constant immersion against the chemical mixture. The second method uses tensile strength to assess molecular changes in the polymer structure.

This study is focused on addressing three issues of concern. First, this study examines …

Characterization Of Fall Leaves As A Source Of Cellulosic Ethanol, Justin Burum

Journal of Undergraduate Research at Minnesota State University, Mankato

Ethanol is becoming increasingly popular as a fossil fuel additive or substitute. However, current production of ethanol from corn impacts food prices and appears to have an overall low net yield. New sources need to be identified and new processes developed for ethanol production. Cellulosic ethanol is one such new source. Plant material contains a large amount of cellulose and other polysaccharides which are potential feed stocks for ethanol production. The purpose of this experiment was to characterize the polysaccharide, lignin, and ash content of fall leaves to estimate their potential for ethanol production. A slight modification of the NREL …