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Articles 1261 - 1290 of 1491

Full-Text Articles in Chemistry

Development Of An Analytical Method For Distinguishing Ammonium Bicarbonate From The Products Of An Aqueous Ammonia Co2 Scrubber And The Characterization Of Ammonium Bicarbonate, Lingyu Meng Jan 2004

Development Of An Analytical Method For Distinguishing Ammonium Bicarbonate From The Products Of An Aqueous Ammonia Co2 Scrubber And The Characterization Of Ammonium Bicarbonate, Lingyu Meng

Masters Theses & Specialist Projects

The link between anthropogenic emissions of CO2 with increased atmospheric CO2 levels and, in turn, with increased global temperature has been well established and accepted. Using aqueous ammonia to capture CO2 and produce an inexpensive nitrogen fertilizer, ammonium bicarbonate (ABC) has been thought as a feasible approach to CO2 sequestration.

Due to the different concentrations of reactants and reaction conditions, different carbon-ammonium composites can be produced. In view of achieving a maximum of NH3 utilization in the capture of CO2, the product of ABC will be ideal. Hence the ABC in the products needs to be identified. Various analytical techniques …


Infrared Thermal Imaging Of Automobiles: Identification Of Cold Start Vehicles, Angela M. Monateri, Donald H. Stedman Jan 2004

Infrared Thermal Imaging Of Automobiles: Identification Of Cold Start Vehicles, Angela M. Monateri, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Application Of Pyrolysis-Gc/Ms For Rapid Assessment Of Organic Contamination In Sediments From Barcelona Harbor, Michael A. Kruge, Albert Permanyer Jan 2004

Application Of Pyrolysis-Gc/Ms For Rapid Assessment Of Organic Contamination In Sediments From Barcelona Harbor, Michael A. Kruge, Albert Permanyer

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Pyrolysis-GC/MS is advantageous as a tool for rapid sediment contamination assessment because of the small sample size required, minimal sample preparation, and its ability to detect a wide variety of organic pollutants as well as naturally-occurring biological materials. Py-GC/MS was applied, together with determination of organic carbon, and major and minor element concentrations, to evaluate potentially contaminated sediments in the port of Barcelona (Spain) and the adjacent Llobregat River delta. Detected contaminant markers, most evident in the Old Port (Port Vell) area, included hopanes and alkylated PAHs (petroleum), sterenes (sewage), C16-C19 phenylalkanes (detergents) and parent …


On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Year 1, September 2003, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2004

On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Year 1, September 2003, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The La Brea Area: Year 3, October 2003, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2004

On-Road Remote Sensing Of Automobile Emissions In The La Brea Area: Year 3, October 2003, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


High Temperature And Fuel Impacts On Hc Emissions (Presentation), Richard Barrett, Donald H. Stedman Jan 2004

High Temperature And Fuel Impacts On Hc Emissions (Presentation), Richard Barrett, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Infrared Thermal Imaging Of Automobiles (Presentation), Angela M. Monateri, Donald H. Stedman, Gary A. Bishop Jan 2004

Infrared Thermal Imaging Of Automobiles (Presentation), Angela M. Monateri, Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Emissions In Asia Measured By Remote Sensing, Donald H. Stedman, Gary A. Bishop, Niranjan Vescio, Nitin Manawat, Peter Mcclintock Jan 2004

On-Road Emissions In Asia Measured By Remote Sensing, Donald H. Stedman, Gary A. Bishop, Niranjan Vescio, Nitin Manawat, Peter Mcclintock

Fuel Efficiency Automobile Test Publications

On-road emissions are precisely the emissions which are impacting the air quality and which need to be controlled if air quality improvements are desired. Remote sensing measures mass emissions of CO, HC, NO and smoke per kg (or per L) of fuel burned. On-road emissions are not certification emissions for new vehicles, although new vehicles measured on-road most often provide remote sensing readings well within their certification values. On-road emissions are not the same as readings from scheduled emission tests, although on average the two correlate very well. The major difference between scheduled emission tests and on-road emissions readings is …


Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle Jan 2004

Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Measurements of methyl chloride (CH3Cl) in Antarctic polar ice and firn air are used to describe the variability of atmospheric CH3Cl during the past 300 years. Firn air results from South Pole and Siple Dome suggest that the atmospheric abundance of CH3Cl increased by about 10% in the 50 years prior to 1990. Ice core measurements from Siple Dome provide evidence for a cyclic natural variability on the order of 10%, with a period of about 110 years in phase with the 20th century rise inferred from firn air. Thus, the CH3Cl increase measured in firn air may largely be …


Methyl Bromide In Preindustrial Air: Measurements From An Antarctic Ice Core, Eric S. Saltzman, Murat Aydin, Warren J. De Bruyn, Daniel B. King, Shari A. Yvon-Lewis Jan 2004

Methyl Bromide In Preindustrial Air: Measurements From An Antarctic Ice Core, Eric S. Saltzman, Murat Aydin, Warren J. De Bruyn, Daniel B. King, Shari A. Yvon-Lewis

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

This paper presents the first ice core measurements of methyl bromide (CH3Br). Samples from a shallow Antarctic ice core (Siple Dome, West Antarctica), ranging in mean gas dates from 1671 to 1942, had a mean CH3Br mixing ratio of 5.8 ppt. These results extend the existing historical record derived from air and Antarctic firn air to about 350 years before present. Model simulations illustrate that the ice core results are consistent with estimates of the impact of anthropogenic activity ( fumigation, combustion, and biomass burning) on the atmospheric CH3Br burden, given the large current uncertainties in the modern atmospheric CH3Br …


Development And Optimization Of Hplc-Icpms For The Determination Of Iodine Speciation In Groundwater, Yun Qiu Dec 2003

Development And Optimization Of Hplc-Icpms For The Determination Of Iodine Speciation In Groundwater, Yun Qiu

All-Inclusive List of Electronic Theses and Dissertations

High performance liquid chromatography has been coupled with online inductively coupled plasma mass spectrometry detection for the determination of iodine speciation in drinking and groundwaters. Using ion exchange chromatography, the method is applied to quantify the concentrations of iodine species in groundwaters. The HPLC-UV detection was used first to examine the separation efficiency of the HPLC method. The limit of quantification was obtained for the HPLC-UV analysis. Direct ICPMS analysis of iodine species has been validated and optimized using an HC03"/C03 2 - aqueous solvent. HPLC was then interfaced to the ICPMS T-shape connection to allow online addition of internal …


Support For The Nye County Early Warning Drilling Program, Irene Farnham, Klaus J. Stetzenbach, Amy J. Smiecinski Nov 2003

Support For The Nye County Early Warning Drilling Program, Irene Farnham, Klaus J. Stetzenbach, Amy J. Smiecinski

Publications (YM)

This final report details the activities completed for Task 8 of the University and Community College System of Nevada (UCCSN) Cooperative Agreement with the US Department of Energy (DOE). Task 8, titled "Support for the Nye County Early Warning Drilling Program" provided for a variety of hydrochemical analyses. The requirements of the University and Community College System of Nevada (UCCSN) Quality Assurance (QA) Program were followed for all work performed on this task. The primary activity performed by the Harry Reid Center for Environmental Studies (HRC) for Task 8 was to provide hydrochemical analyses of the groundwater samples collected from …


Acid-Base Properties Of Aluminum In A Hardwood Forest Soil (Or: Acid Rain Is Dead…), Chris E. Johnson Nov 2003

Acid-Base Properties Of Aluminum In A Hardwood Forest Soil (Or: Acid Rain Is Dead…), Chris E. Johnson

Civil and Environmental Engineering - All Scholarship

No abstract provided.


Redox Scale For Assigning An Oxidizing/Reducing Potential To Groundwater: Method Development And Initial Results, Julie Bertoia, Vernon Hodge, Klaus J. Stetzenbach, Amy J. Smiecinski Oct 2003

Redox Scale For Assigning An Oxidizing/Reducing Potential To Groundwater: Method Development And Initial Results, Julie Bertoia, Vernon Hodge, Klaus J. Stetzenbach, Amy J. Smiecinski

Publications (YM)

This report outlines the progress on Task 33 of the Department of Energy's Yucca Mountain Cooperative Agreement with the University and Community College System of Nevada (UCCSN). The task is titled "The Experimental Determination of a "Redox Scale" for Assigning an Oxidizing/Reducing Potential to Groundwater from Wells in the Nye County Early Warning Drilling Program: A Scale for Predicting the Solubility and Mobility of Elements Commonly Found in Nuclear Wastes". The purpose of the research was to determine the concentrations of the various electrochemical oxidation states or redox species of eleven elements in groundwater samples collected from the Nye County …


Corrosion And Mass Transport Processes In Carbon Steel Miniature Waste Packages, James Cizdziel, Kaveh Zarrabi, Susan Lestrange, Amy J. Smiecinski Oct 2003

Corrosion And Mass Transport Processes In Carbon Steel Miniature Waste Packages, James Cizdziel, Kaveh Zarrabi, Susan Lestrange, Amy J. Smiecinski

Publications (YM)

In this study, we have systematically investigated corrosion and mass transport processes in carbon steel miniature waste packages (MWP) in dynamic systems (water in, water out) under varying chemical conditions. The MWP were fabricated to have similar configuration to the DOE Spent Nuclear Fuel (SNF) waste package and that individual components to be in scale with each other compare to the SNF waste package. Two MWP configurations were studied: a "bathtub" model and a "flow-through" model. By slowly dripping 4 different solutions (groundwater obtained from well water J-13 located near Yucca Mountain, and J-13 water adjusted to low-pH, high-salinity, and …


Distributions Of Trace Gases And Aerosols During The Dry Biomass Burning Season In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirchstetter Sep 2003

Distributions Of Trace Gases And Aerosols During The Dry Biomass Burning Season In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Donald R. Blake, Song Gao, Thomas W. Kirchstetter

Chemistry and Physics Faculty Articles

Vertical profiles in the lower troposphere of temperature, relative humidity, sulfur dioxide (SO2), ozone (O3), condensation nuclei (CN), and carbon monoxide (CO), and horizontal distributions of twenty gaseous and particulate species, are presented for five regions of southern Africa during the dry biomass burning season of 2000. The regions are the semiarid savannas of northeast South Africa and northern Botswana, the savanna-forest mosaic of coastal Mozambique, the humid savanna of southern Zambia, and the desert of western Namibia. The highest average concentrations of carbon dioxide (CO2), CO, methane (CH4), O3, …


Emissions Of Trace Gases And Particles From Savanna Fires In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Isaac T. Bertschi, Donald R. Blake, Isobel J. Simpson, Song Gao, Thomas W. Kirchstetter, Tihomir Novakov Jul 2003

Emissions Of Trace Gases And Particles From Savanna Fires In Southern Africa, Parikhit Sinha, Peter V. Hobbs, Robert J. Yokelson, Isaac T. Bertschi, Donald R. Blake, Isobel J. Simpson, Song Gao, Thomas W. Kirchstetter, Tihomir Novakov

Chemistry and Physics Faculty Articles

Airborne measurements made on initial smoke from 10 savanna fires in southern Africa provide quantitative data on emissions of 50 gaseous and particulate species, including carbon dioxide, carbon monoxide, sulfur dioxide, nitrogen oxides, methane, ammonia, dimethyl sulfide, nonmethane organic compounds, halocarbons, gaseous organic acids, aerosol ionic components, carbonaceous aerosols, and condensation nuclei (CN). Measurements of several of the gaseous species by gas chromatography and Fourier transform infrared spectroscopy are compared. Emission ratios and emission factors are given for eight species that have not been reported previously for biomass burning of savanna in southern Africa (namely, dimethyl sulfide, methyl nitrate, five …


Evolution Of Gases And Particles From A Savanna Fire In South Africa, Peter V. Hobbs, Parikhit Sinha, Robert J. Yokelson, Ted J. Christian, Donald R. Blake, Song Gao, Thomas W. Kirchstetter, Tihomir Novakov, Peter Pilewskie Jul 2003

Evolution Of Gases And Particles From A Savanna Fire In South Africa, Peter V. Hobbs, Parikhit Sinha, Robert J. Yokelson, Ted J. Christian, Donald R. Blake, Song Gao, Thomas W. Kirchstetter, Tihomir Novakov, Peter Pilewskie

Chemistry and Physics Faculty Articles

Airborne measurements of particles and gases from a 1000-ha savanna fire in South Africa are presented. These measurements represent the most extensive data set reported on the aging of biomass smoke. The measurements include total concentrations of particles (CN), particle sizes, particulate organic carbon and black carbon, light-scattering coefficients, downwelling UV fluxes, and mixing ratios for 42 trace gases and 7 particulate species. The ratios of excess nitrate, ozone, and gaseous acetic acid to excess CO increased significantly as the smoke aged over ∼40–45 min, indicating that these species were formed by photochemistry in the plume. For 17 other species, …


Water-Soluble Organic Components In Aerosols Associated With Savanna Fires In Southern Africa: Identification, Evolution, And Distribution, Song Gao, Dean A. Hegg, Peter V. Hobbs, Thomas W. Kirchstetter, Brian I. Magi, Martin Sadilek Mar 2003

Water-Soluble Organic Components In Aerosols Associated With Savanna Fires In Southern Africa: Identification, Evolution, And Distribution, Song Gao, Dean A. Hegg, Peter V. Hobbs, Thomas W. Kirchstetter, Brian I. Magi, Martin Sadilek

Chemistry and Physics Faculty Articles

During the SAFARI 2000 field campaign, both smoke aerosols from savanna fires and haze aerosols in the boundary layer and in the free troposphere were collected from an aircraft in southern Africa. These aerosol samples were analyzed for their water-soluble chemical components, particularly the organic species. A novel technique, electrospray ionization-ion trap mass spectrometry, was used concurrently with an ion chromatography system to analyze for carbohydrate species. Seven carbohydrates, seven organic acids, five metallic elements, and three inorganic anions were identified and quantified. On the average, these 22 species comprised 36% and 27% of the total aerosol mass in haze …


Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic Mar 2003

Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic

Theses and Dissertations

Perchloroethene (PCE), Trichloroethene (TCE) and their degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands utilizing upward flow harbor reduction-oxidation conditions that have demonstrated the potential to promote both partial and total mineralization of PCE and TCE through the process of natural attenuation. Organic acid and inorganic anion concentrations are indicative of reduction-oxidation processes that drive chlorinated ethene degradation. These analytes were investigated to assess their development within three vertically stratified regions of a constructed wetland cell at Wright-Patterson Air Force Base fed by groundwater contaminated with PCE and TCE. Data collected during …


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 5, September 2002, Gary A. Bishop, Mitchell J. Williams, Daniel A. Burgard, Donald H. Stedman Jan 2003

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 5, September 2002, Gary A. Bishop, Mitchell J. Williams, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 4, January 2003, Daniel A. Burgard, Gary A. Bishop, Mitchell J. Williams, Donald H. Stedman Jan 2003

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 4, January 2003, Daniel A. Burgard, Gary A. Bishop, Mitchell J. Williams, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Labrea Area: Year 2, Mitchell J. Williams, Gary A. Bishop, Donald H. Stedman Jan 2003

On-Road Remote Sensing Of Automobile Emissions In The Labrea Area: Year 2, Mitchell J. Williams, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 4, November 2002, Gary A. Bishop, Daniel A. Burgard, Mitchell J. Williams, Donald H. Stedman Jan 2003

On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 4, November 2002, Gary A. Bishop, Daniel A. Burgard, Mitchell J. Williams, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


A Five-Channel, Single Detector, Emission Rmote Sensor (Presentation), Mitchell J. Williams, Donald H. Stedman, Gary A. Bishop, Richard W. Quine Jan 2003

A Five-Channel, Single Detector, Emission Rmote Sensor (Presentation), Mitchell J. Williams, Donald H. Stedman, Gary A. Bishop, Richard W. Quine

Fuel Efficiency Automobile Test Publications

No abstract provided.


Feat Standard Operating Procedures, Donald H. Stedman, Gary A. Bishop Jan 2003

Feat Standard Operating Procedures, Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Feat Monochromater User's Guide, Gary A. Bishop Jan 2003

Feat Monochromater User's Guide, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Modeling And Design Of Polythiophene Gate Electrode Chemfets For Environmental Pollutant Sensing, T. V. Krishna, Jeffrey R. Jessing, Dale D. Russell, Jonathan Scaggs, Lisa R. Warner, Joe A. Hartman Jan 2003

Modeling And Design Of Polythiophene Gate Electrode Chemfets For Environmental Pollutant Sensing, T. V. Krishna, Jeffrey R. Jessing, Dale D. Russell, Jonathan Scaggs, Lisa R. Warner, Joe A. Hartman

Chemistry and Biochemistry Faculty Publications and Presentations

Water-borne pollutants such as volatile organic compounds are a serious environmental concern, which has increased the demand for chemical sensing elements. Solidstate sensors based on catalytic gate devices are a subject of current research, however they are restricted in practical applications because of their inability to operate at room temperature. Conducting polymer FETs, which employ a conducting gate polymer, have received much attention due to their unique electronic and optical properties. Polythiophene is chosen as the semi-conductive gate polymer in this work. A functional group attached to the polythiophene is used to detect analytes (i.e., mercury in this work) of …


The Redox Potential Of Ddt: An Environmental Perspective, Anne Lewis, Christopher Cramer, John Bumpus Jan 2003

The Redox Potential Of Ddt: An Environmental Perspective, Anne Lewis, Christopher Cramer, John Bumpus

Presidential Scholars Theses (1990 – 2006)

Due to their low water solubility, the reduction potentials of DDT and dicofol are difficult to determine experimentally. Through computational methods, we calculated the one and two electron reduction potentials for DDT as 0.51 V and 0.67 V, respectively, and those for dicofol were 0.50 V and 0.74 V. This study is significant because we are able to calculate reliable redox potentials that may be utilized to predict chemical behavior and degradation pathways of environmental pollutants. To assess the accuracy of theoretical chemistry, we compared experimental and computational data and examined whether our calculated redox potentials fit with the known …


The Aqueous Phase Yield Of Alkyl Nitrates From Roo+No: Implications For Photochemical Production In Seawater, Elizabeth E. Dahl, Eric S. Saltzman, Warren J. De Bruyn Jan 2003

The Aqueous Phase Yield Of Alkyl Nitrates From Roo+No: Implications For Photochemical Production In Seawater, Elizabeth E. Dahl, Eric S. Saltzman, Warren J. De Bruyn

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Alkyl nitrates have been observed in remote oceanic regions of the troposphere and in the surface ocean. The mechanism for their production in the oceans is not known. A likely source is the reaction of ROO + NO (where R is an alkyl group). Steady-state laboratory experiments show that alkyl nitrates are produced in the aqueous phase via this reaction, with branching ratios of 0.23 +/- 0.04, 0.67 +/- 0.03, and 0.71 +/- 0.04 for methyl, ethyl, and propyl nitrate respectively. The branching ratios in aqueous solution are significantly higher than in the gas phase. Irradiation of surface seawaters yield …