Chemistry Commons^™

Winter Measurements Of Heavy-Duty Vehicles To Characterize The Cold Temperature Effectiveness Of Selective Catalytic Reductions Catalyst In Controlling Oxide Of Nitrogen Emissions, Gary A. Bishop, Molly J. Haugen, Brian C. Mcdonald

Fuel Efficiency Automobile Test Publications

No abstract provided.

Does California’S Emfac2017 Vehicle Emissions Model Under-Predict California Light-Duty Gasoline Vehicle Nox Emissions?, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

On-road remote sensing measurements of light and medium-duty gasoline vehicles collected within California’s South Coast Air Basin since 1999 generally fall within the range of observed summer ambient molar NO_x/CO measurements collected during morning rush hours. Compared with ambient and on-road emissions, the California Air Resources Board EMFAC model under predicts 2018 gasoline vehicle NO_x emission factors by more than a factor of 2.6. Contributing to these differences is that vehicles older than model year 2006 have NO_x emission deterioration rates that are up to 4 time’s higher on-road than predicted by the EMFAC model. A …

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2020, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

On-Road Remote Sensing Of Automobile Emissions In The Fresno, Ca Area: Spring 2021, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Stockton Ca Data Summary, Gary Bishop

Fuel Efficiency Automobile Test Publications

Simple data summary for on-road emission measurements from Stockton CA.

Iron Speciation In Pm2.5 From Urban, Agriculture, And Mixed Environments In Colorado, Usa, Joseph R. Salazar, David J. Pfotenhauer, Frank Leresche, Fernando L. Rosario-Ortiz, Michael P. Hannigan, Sirine C. Fakra, Brian Majestic

Chemistry and Biochemistry: Faculty Scholarship

Atmospheric iron solubility varies depending on whether the particles are collected in rural or urban areas, with urban areas showing increased iron solubility. In this study, we investigate if the iron species present in different environments affects its ultimate solubility. Field data are presented from the Platte River Air Pollution and Photochemistry Experiment (PRAPPE), aimed at understanding the interactions between organic carbon and trace elements in atmospheric particulate matter (PM). 24-hr PM2.5 samples were collected during the summer and winter (2016–2017), at three different sites on the Eastern Colorado plains: an urban, agricultural, and a mixed site. Downtown Denver had …

California - Cottonwood Weigh Station, University Of Denver

On-road Heavy-duty Monitoring System Measurements

Relevant Publications

Environmental Science & Technology Publication (2015)

Environmental Science & Technology Publication (2017)

Environmental Science & Technology Publication (2018)

Final Report

California - Port Of Los Angeles, Unversity Of Denver

On-road Heavy-duty Monitoring System Measurements

Relevant Publications

Environmental Science & Technology Publication (2015)

Environmental Science & Technology Publication (2017)

Environmental Science & Technology Publication (2018)

Final Report

Controlling Transition Metal-Catalyzed Alkyne Annulations Utilizing Polarized Ynol Ethers, Brandon L. Coles-Taylor

Electronic Theses and Dissertations

Transition metal-catalyzed alkyne annulations have developed into incredibly powerful synthetic tools over there the past quarter century. These reactions provide rapid access to important organic scaffolds such as indole, quinoline, isoquinoline, indene, and isocoumarin scaffolds. Transition metal mediated alkyne annulations have proven invaluable in synthetic fields, such as natural product total synthesis, by offering efficient pathways to otherwise synthetically difficult to access substrates.

Foundational works performed by chemist such as Larock, Ackermann, Satoh, and Miura have been established through relying upon the usage of symmetrical alkynes. When unsymmetrical alkynes are used in annulation processes mixtures of regioisomers are often isolated. …

Iron In Urban Air Pollution, Joseph R. Salazar

Electronic Theses and Dissertations

The processes by which iron is solubilized are largely unknown. There are three hypotheses on how iron is soluble: 1) iron is thought to undergo an acid based solubilization process, 2) iron undergoes an oxidation/reduction process and reduces iron(III) to the more soluble iron(II), and 3) iron is bound to organic molecules, which solubilizes it. The 3 hypotheses on iron water-solubilized are explored by presenting two individual studies.

The first study investigates iron directly from car exhaust. Exhaust particles were collected from 32 vehicles. Iron solubility in these samples ranged from 0%-82% with the average iron solubility being 30%. X-ray …

Instrument And Application Development In Saturation Recovery And Rapid Scan Electron Paramagnetic Resonance, Joseph E. Mcpeak

Electronic Theses and Dissertations

Enhanced signal sensitivity by the use of Rapid Scan (RS) electron paramagnetic resonance (EPR), a technique that allows for much faster magnetic field scans than traditional field-swept techniques, has facilitated improved data acquisition for many types of samples. For example, irradiated fingernails for radiation dosimetry have been studied using RS-EPR, which resulted in substantial decreases in detection limits. Samarium-mediated reduction mechanisms in organic synthesis have been investigated by RS-EPR providing evidence for a radical intermediate. Spectra of organic radicals exhibiting both narrow lines and closely spaced hyperfine interactions have been recorded via RS-EPR. Well-resolved spectra can be recorded at a …

Development Towards An Ethylene Sensing Artificial Metalloenzyme, Mitchell Lee Ellinwood

Electronic Theses and Dissertations

Ethylene (ethene) is the essential ripening hormone for climacteric plants, and consequently its detection and quantification is of considerable interest to the horticulture industry. Its detection however is a non-trivial pursuit, traditionally requiring expensive and inaccessible instrumentation that fail to provide in vivo information about ethylene. A ruthenium based fluorescent probe for the selective detection of ethylene has recently been developed, and it was envisioned that this probe could be made biocompatible by encasing it within a protein scaffold making it an artificial metalloenzyme. To this end biotinylated N-heterocyclic carbenes (NHCs) were synthesized, which can be appended onto the ruthenium …

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Winter 2020, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Majestic - Prappe Metals Data, Brian Majestic

Chemistry and Biochemistry: Data Sets

No abstract provided.

Are Electric Vehicles A Panacea For Reducing Ozone Precursor Emissions?, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Vehicle Exhaust Remote Sensing Device Method To Screen Vehicles For Evaporative Running Loss Emissions, Gary A. Bishop, Timothy H. Defries, James A. Sidebottom, James M. Kemper

Fuel Efficiency Automobile Test Publications

Vehicle hydrocarbon (HC) emissions can be emitted from either tailpipe or non-tailpipe locations and understanding their fleet apportionment is important for successful air pollution policy. Vehicles initially misidentified as having elevated tailpipe HC emissions first indicated that roadside exhaust sensors could detect the presence of evaporative HC emissions as increased noise in the HC/carbon dioxide (CO₂) correlation measurement. The 90^th percentile of the largest residual of the HC/CO₂ correlation is defined as a running loss index (RLI) for each measurement. An RLI that is three standard deviations or greater above the instruments noise indicates possible evaporative …

On-Road Remote Sensing Of Automobile Emissions In The Tulsa Area: Fall 2019, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Inspection And Maintenance Evaluation Using Historical U.S. Remote Sensing Measurements, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Development And Characterization Of An Inexpensive Single-Particle Fluorescence Spectrometer For Detection And Classification Of Pollen And Other Bioaerosols, Benjamin E. Swanson

Electronic Theses and Dissertations

Atmospheric aerosols are ubiquitous throughout the Earth’s atmosphere and can be important with respect to environmental systems and human health. Pollen particles are a class of primary biological aerosol particles (PBAPs) that cost the United States billions of dollars a year in loss of productivity and healthcare costs due to allergy and respiratory effects. Traditional methods of pollen detection rely on collection and subsequent identification by visual microscopy, yet few measurement stations exist in the United States. As such, current pollen forecasting models have relatively high prediction uncertainty, especially in regions without sampling stations. Recently, laser-induced fluorescence instrumentation has been …

Development Of A Hek293 Cell Line To Show Inhibition Of Tau Aggregation, Justin Ray Shady

Electronic Theses and Dissertations

Intracellular deposition of aggregated tau is the hallmark of several different tauopathies, the most widespread of these being Alzheimer's disease. Tau is a highly soluble, intrinsically disordered, microtubule associated protein. Tau's native function is to stabilize microtubule formation in the axons of neurons. Post translational modification such as hyperphosphorylation as well as several familial mutations allow tau to nucleate and form fibrils. These fibrils can recruit healthy monomers onto their ends in a fashion described as template-assisted growth. Tau has 6 isoforms that vary by the inclusion or exclusion of two N-terminal repeats and the inclusion or exclusion of the …

Photoassisted Synthesis Of Complex Polyheterocycles Via Esipt-Driven Dearomative Intramolecular Cycloadditions, Dmitry Kuznetsov

Electronic Theses and Dissertations

This research is focused on the development of novel photoassisted synthetic methodologies that provide straightforward access to complex and diverse libraries of polyheterocycles from modularly assembled precursors. All methods are based on the dearomative cycloadditions between two components: (i) o-azaxylylenes, generated by the excited-state intramolecular proton transfer, and (ii) tethered arene groups.

We have demonstrated the synthetic utility of four new photoinduced processes that yield complex products amenable for post-photochemical modifications:

• [4+4] Cycloaddition of o-azaxylylenes to 1,3,4-oxadiazoles with subsequent dinitrogen extrusion. This reaction furnishes compounds outfitted with epoxide fragments, which undergo ring-openings with various nucleophiles; furthermore, the oxidized products …

Three Decades Of On-Road Mobile Source Emissions Reductions In South Los Angeles, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

In May of 2018, the University of Denver repeated on-road optical remote sensing measurements at two locations in Lynwood, CA. Lynwood area vehicle tailpipe emissions were first surveyed in 1989 and 1991 because the area suffered with a large number of carbon monoxide (CO) air quality violations. These new measurements allow for the estimation of fuel specific CO and total hydrocarbon (HC) emissions reductions, changes in the longevity of emission-control components, and the prevalence of high emitters in the current fleet.

Since 1989 CO emissions decreased approximately factors of 10 (120 ± 8 to 12.3 ± 0.2 gCO/kg of fuel) …

Rapid-Scan Epr And Imaging, Yilin Shi

Electronic Theses and Dissertations

EPR imaging at low frequency is a powerful tool to obtain important biological information in vivo in a non-invasive way. Properties of nitroxide and trityl radical imaging reagents have been studied. Developments in rapid scan imaging techniques are reported that improve efficiency of experiments and user-friendliness of software.

Relaxation and signal-to-noise ratio (S/N) in pulse experiments on trityl radicals were measured at frequencies between 400 MHz and 1.5 GHz. Relaxation time increases as the frequency increases and the radical concentration decreases. Since relaxation time is a sensitive and accurate measure of oxygen pressure, this study provides criteria for the selection …

Measuring Emissions From The On-Road Vehicle Fleet In West Los Angeles, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Fall 2018, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.

Lewis Base Promoted Annulations Of Allenoates With 1,4-Naphthoquinones, Nicole Marie Shoup

Electronic Theses and Dissertations

Lewis base promoted cyclization of allenoates with electron deficient olefins open up the possibility to generate more complex organic structures. By generating more complex molecules, we are able to produce new compounds for biomedical and material applications. Both phosphine and amine Lewis bases offer interesting annulations with allenoates resulting in Lu or Morita–Baylis–Hillman type reactions. Once the Lewis base engages with the allenoate there can be several modes of nucleophilic reactivity that allows for the allenic ester to act as a two or three carbon synthon. The allenoate can then react with varying electron deficient olefins generating more complex molecules …

Fuel Specific Emissions Trends For In-Use Medium And Heavy-Duty Vehicle Fleets In California, Molly J. Haugen

Electronic Theses and Dissertations

New heavy-duty vehicle regulations have caused significant reductions in hazardous air pollutants, such as particulate matter (PM) and nitrogen oxides (NO_x), due to better engine management and utilization of advanced after-treatment systems. The University of Denver has collected data for gaseous and PM emission measurements from on-road heavy-duty vehicles (HDVs). The On-Road Heavy-Duty Vehicle Emissions Measurement System (OHMS) collected fuel specific emission information on individual HDVs of in-use fleets at two California locations in the spring of 2013, 2015 and 2017. These complimentary fleets, studied over multiple years, produced 7,075 measurements of gaseous and particle emission data providing …

Brønsted Acid Catalyzed Carbon-Carbon Bond Forming Reactions, Jiangyue Miao

Electronic Theses and Dissertations

The focus of this research project lies in the development of new methodology in the field of Brønsted acid catalysis enabling rapid synthesis of medicinally relevant compounds. It is foreseen that small molecule sulfonic acids evaluated in this research project will unveil new asymmetric carbon carbon bond forming reactions between substrates hitherto unexplored with Brønsted acid catalysis. It has been established that strong Brønsted acids, such as phosphoric acids, are capable of mediating highly selective transformations operating through unique mechanistic manifolds.

Specific focus for the sulfonic acid catalysts was geared towards asymmetric coupling reactions with synthetically useful precursors such as …

Selective Carbon-Carbon Bond Formation Promoted By Divalent Samarium Reagents, Christopher David-James Aretz

Electronic Theses and Dissertations

Three efficient methods for synthesis of five membered carbocycles, a highly understudied product motif in samarium(II) chemistry, were explored and optimized. These methods utilized simple starting materials to generate linear substrates with functional groups that are reactive towards samarium(II) iodide. The three methods explored were the Reformatsky-aldol, Reformatsky-alkylation, and pinacol cyclizations. The critical discovery for efficient formation of the Reformatsky-aldol and pinacol carbocycles products was the use of lithium bromide. This addition of lithium bromide facilitates easy in situ formation of samarium(II) bromide. The Reformatsky-alkylation cyclization was a newly realized reaction employing samarium enolates. Two of the three methods, the …

Photochemistry Of Polycyclic Aromatic Hydrocarbons With Environmentally Relevant Metals, John P. Haynes

Electronic Theses and Dissertations

The details of the work presented in this dissertation focus on simulated reactions in the atmosphere and water systems between persistent aromatic compounds and varying species of metals with an emphasis on iron. Bulk water suspensions of a standard soil and polycyclic aromatic hydrocarbons (PAH) were analyzed for soluble iron by inductively-coupled plasma mass spectroscopy (ICP-MS) following a 16 hour reaction period using simulated sunlight. Significant increases in soluble iron were only seen with 2-3 ring linear PAH and carboxylic acids.

A two-stage study was conducted to investigate the potential for and possible mechanisms involving the photo-oxidation of PAH into …