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Full-Text Articles in Physical Sciences and Mathematics

Synthesis, Characterization, And Kinetics Studies Of New Cobalt Complexes For The Production Of H2 In Acidic Media, Michael John Celestine Dec 2020

Synthesis, Characterization, And Kinetics Studies Of New Cobalt Complexes For The Production Of H2 In Acidic Media, Michael John Celestine

Chemistry & Biochemistry Theses & Dissertations

The kinetics and mechanism of the oxidation of [Co(dmgBF2)2(OH2)2] (where dmgBF2 = difluoroboryldimethylglyoximato) by sodium hypochlorite (NaOCl), sodium bromate (NaBrO3), and bromine (Br2) was investigated by stopped-flow spectrophotometry at 450 nm over a wide temperature range. The pKa1 value for [Co(dmgBF2)2(OH2)2] was calculated as 5.27 ± 0.14 at I = 0.60 (NaCl). From the variation in pH studies, the activation parameters were derived from the proposed mechanisms for NaOCl, ΔH1*, ΔH2*, ΔS1*, and …


Effect Of Reworking And Bioturbation On Sedimentary Reactive Iron Within A Microtidal Estuary, Amy Kathleen Pitts Oct 2011

Effect Of Reworking And Bioturbation On Sedimentary Reactive Iron Within A Microtidal Estuary, Amy Kathleen Pitts

OES Theses and Dissertations

Mixed redox conditions in sediments due to physical reworking may allow for enhanced remineralization of refractory organic matter due to Fe(III) redox cycling. In part this may occur because easily reducible iron oxides can be used by heterotrophic bacteria to remineralize the organic carbon. This phenomena has been observed in bioturbated sediments and in areas where physical factors (such as strong bottom currents) constantly rework the sediments. To specifically determine the effects of physical reworking and bioturbation on concentrations of easily reducible iron oxides, reactive iron concentrations were measured in surface sediments taken from two contrasting sites in the York …


Molecular Characterization Of The Soluble Fraction Of Atmospheric Particulate Matter Obtained By Chemical Oxidation With Nitric Acid, Amanda Susan Priest Apr 2010

Molecular Characterization Of The Soluble Fraction Of Atmospheric Particulate Matter Obtained By Chemical Oxidation With Nitric Acid, Amanda Susan Priest

Chemistry & Biochemistry Theses & Dissertations

The availability of information regarding the composition of ambient atmospheric particulate matter and the transformations that these compounds may undergo upon atmospheric transit is surprisingly absent. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry is used in this study to rapidly evaluate the composition of the water-soluble organic fraction of standard and collected atmospheric particulate matter samples, and the changes that these mixtures undergo upon oxidation with nitric acid. The standard samples include representative particulate matter collected over the course of a year in Washington, D.C. and particulate matter from the exhaust of a diesel-powered engine. The collected sample …


Biostratigraphic Analysis Of Southern Florida's Plio-Pleistocene Shell Beds, Dalton L. Rasmussen Apr 1997

Biostratigraphic Analysis Of Southern Florida's Plio-Pleistocene Shell Beds, Dalton L. Rasmussen

OES Theses and Dissertations

Four molluscan assemblage zones in southern Florida corresponding to the Pinecrest Sand Member of the Tamiami Formation, and the Caloosahatchee, Bermont and Fort Thompson shell beds were identified following quantitative and qualitative analyses of the fossil molluscan fauna. Twenty-eight bulk sediment samples collected from 16 localities across southern Florida were processed for fossil material, and yielded nearly 60,000 specimens belonging to 311 species. A Q-mode cluster analysis compared sediment samples on the basis of 188 species whose abundances had been converted to binary presence-absence form. The cluster analysis was run four times using the Jaccard and Dice similarity coefficients as …


A Diffuse Reflectance Infrared Fourier Transform Spectroscopic Investigation Of The Oxidation Of Co On Platinum/Tin(Iv) Oxide-Based Catalysts, Julie Christi Stiltner Patrick Jul 1994

A Diffuse Reflectance Infrared Fourier Transform Spectroscopic Investigation Of The Oxidation Of Co On Platinum/Tin(Iv) Oxide-Based Catalysts, Julie Christi Stiltner Patrick

Chemistry & Biochemistry Theses & Dissertations

Platinum/tin(IV) oxide-based catalysts have been developed for the oxidation of carbon monoxide at 55 °C and 1 atmosphere pressure. A diffuse reflectance infrared fourier transform spectroscopic (DRIFTS) investigation of this oxidation has been performed. Four catalyst samples have been subjected to a 5% carbon monoxide pretreatment at 125 °C, helium exposure at 55 °C, bottled air (20% oxygen) exposure at 55 °c, and exposure to a 2:1 stoichiometric mixture of carbon monoxide and oxygen at 55 °C. During the course of these exposures, evidence for the development of two different surface carbon monoxide configurations has been found: one that is …