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Articles 61 - 90 of 171

Full-Text Articles in Chemistry

Hydrocarbons In The Upper Troposphere And Lower Stratosphere Observed From Ace-Fts And Comparisons With Waccm, Mijeong Park, William J. Randel, Douglas E. Kinnison, Louisa K. Emmons, Peter F. Bernath, Kaley A. Walker, Chris D. Boone, Nathaniel J. Livesey Jan 2013

Hydrocarbons In The Upper Troposphere And Lower Stratosphere Observed From Ace-Fts And Comparisons With Waccm, Mijeong Park, William J. Randel, Douglas E. Kinnison, Louisa K. Emmons, Peter F. Bernath, Kaley A. Walker, Chris D. Boone, Nathaniel J. Livesey

Chemistry & Biochemistry Faculty Publications

Satellite measurements from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) are used to examine the global, seasonal variations of several hydrocarbons, including carbon monoxide (CO), ethane (C2H6), acetylene (C2H2), and hydrogen cyanide (HCN). We focus on quantifying large-scale seasonal behavior from the middle troposphere to the stratosphere, particularly in the tropics, and furthermore make detailed comparisons with the Whole Atmosphere Community Climate Model (WACCM) chemistry climate model (incorporating tropospheric photochemistry, time-varying hydrocarbon emissions, and meteorological fields nudged from reanalysis). Comparisons with Microwave Limb Sounder (MLS) measurements of CO are also included …


Lead Memory In General Aviation Aircraft Engine Emissions, Randal Demik, Jason Keleher, Natalie Kasak, Julius Keller, Alessandro Mazza, Jordan Raess Apr 2012

Lead Memory In General Aviation Aircraft Engine Emissions, Randal Demik, Jason Keleher, Natalie Kasak, Julius Keller, Alessandro Mazza, Jordan Raess

Chemistry Department Faculty Articles

There is interest from environmental organizations and regulating agencies to eliminate lead and reduce pollutants emitted into the atmosphere from general aviation aircraft using 100LL aviation gasoline (Avgas). 100SF (Swift Fuel) is under development by Swift Enterprises as a lead free general aviation alternative fuel product. The purpose of this study is to determine the amount of time required for engines to be free of lead emissions when first introduced to operation using 100SF. This study also investigated the lead cleansing decay profiles of the aircraft engines under 100SF initial operations. Results of this study revealed that a mean engine …


Emission Changes Resulting From The San Pedro Bay, California Ports Truck Retirement Program, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson Jan 2012

Emission Changes Resulting From The San Pedro Bay, California Ports Truck Retirement Program, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson

Fuel Efficiency Automobile Test Publications

Recent US EPA emissions regulations have resulted in lower emissions of particulate matter and oxides of nitrogen from heavy-duty diesel trucks. To accelerate fleet turnover the State of California in 2008 along with the Ports of Los Angeles and Long Beach (San Pedro Bay Ports) in 2006 passed regulations establishing timelines forcing the retirement of older diesel trucks. On-road emissions measurements of heavy-duty diesel trucks were collected over a three-year period, beginning in 2008, at a Port of Los Angeles location and an inland weigh station on the Riverside freeway (CA SR91). At the Port location the mean fleet age …


Multi-Species Remote Sensing Of Vehicle Emissions On Sherman Way In Van Nuys California, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson Jan 2012

Multi-Species Remote Sensing Of Vehicle Emissions On Sherman Way In Van Nuys California, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman, Douglas R. Lawson

Fuel Efficiency Automobile Test Publications

As part of the 2010 Van Nuys tunnel study, researchers from the University of Denver measured on-road fuel-specific light-duty vehicle emissions from nearly 13,000 vehicles on Sherman Way (0.4 miles west of the tunnel) in Van Nuys, CA with its multi-species FEAT remote sensor a week ahead of the tunnel measurements. The remote sensing mean gram per kilogram carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx) measurements are 8.9% lower, 41%, and 24% higher than the tunnel measurements respectively. The remote sensing CO/NOx and HC/NOx mass ratios are 28% lower and 20% higher than …


Multi-Species On-Road Remote Sensing Of Vehicle Emissions In Van Nuys, California – August 2010, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman Jan 2010

Multi-Species On-Road Remote Sensing Of Vehicle Emissions In Van Nuys, California – August 2010, Gary A. Bishop, Brent G. Schuchmann, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Emission Measurements Of Reactive Nitrogen Compounds From Three California Cities, Gary A. Bishop, Allison Peddle, Donald H. Stedman Jan 2010

On-Road Emission Measurements Of Reactive Nitrogen Compounds From Three California Cities, Gary A. Bishop, Allison Peddle, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

The three California cities of San Jose, Fresno and West Los Angeles (wLA) were visited during March 2008 to collect on-road emission measurements of reactive nitrogen compounds from light-duty vehicles. At the San Jose and wLA sites comparison with historical measurements showed that emissions of carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NO) continue to decrease in the on-road fleet yet the ratio of nitrogen dioxide (NO2) to NO in new diesel vehicles appears to be under going large increases. A small fleet of 2007 diesel ambulances measured in Fresno was found to have more than 60% …


Correlation Of The Real-Time Particulate Matter Emissions Measurements Of A Esp Remote Sensing Device (Rsd) And A Dekati Electronic Tailpipe Sensor (Etaps) With Gravimetrically Measured Pm From A Total Exhaust Dilution Tunnel System, Mridul Gautam, Donald H. Stedman, Daniel K. Carder, Benjamin Shade, Nigel Clark, Gregory Thompson, Scott Wayne, Gary A. Bishop, Brent G. Schuchmann, Dan Pope, Niranjan Vescio, Gary Full, Peter Mcclintock, Drew Rau Jan 2010

Correlation Of The Real-Time Particulate Matter Emissions Measurements Of A Esp Remote Sensing Device (Rsd) And A Dekati Electronic Tailpipe Sensor (Etaps) With Gravimetrically Measured Pm From A Total Exhaust Dilution Tunnel System, Mridul Gautam, Donald H. Stedman, Daniel K. Carder, Benjamin Shade, Nigel Clark, Gregory Thompson, Scott Wayne, Gary A. Bishop, Brent G. Schuchmann, Dan Pope, Niranjan Vescio, Gary Full, Peter Mcclintock, Drew Rau

Fuel Efficiency Automobile Test Publications

No abstract provided.


Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 2, 2009, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman Jan 2010

Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 2, 2009, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 3, 2010, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman Jan 2010

Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 3, 2010, Brent G. Schuchmann, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Motor Vehicle Emissions Including Nh3, So2 And No2, Donald H. Stedman, Gary A. Bishop, Allison Peddle Jan 2009

On-Road Motor Vehicle Emissions Including Nh3, So2 And No2, Donald H. Stedman, Gary A. Bishop, Allison Peddle

Fuel Efficiency Automobile Test Publications

No abstract provided.


Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 1, 2008, Gary A. Bishop, Nicolas E. Holubowitch, Donald H. Stedman Jan 2009

Remote Measurements Of On-Road Emissions From Heavy-Duty Diesel Vehicles In California; Year 1, 2008, Gary A. Bishop, Nicolas E. Holubowitch, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Motor Vehicle Emissions Including Ammonia, Sulfur Dioxide And Nitrogen Dioxide (Presentation), Donald H. Stedman, Gary A. Bishop, Allison Peddle Jan 2009

On-Road Motor Vehicle Emissions Including Ammonia, Sulfur Dioxide And Nitrogen Dioxide (Presentation), Donald H. Stedman, Gary A. Bishop, Allison Peddle

Fuel Efficiency Automobile Test Publications

No abstract provided.


Portable Emission Measurements Of Yellowstone Park Snowcoaches And Snowmobiles, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman, John D. Ray Jan 2009

Portable Emission Measurements Of Yellowstone Park Snowcoaches And Snowmobiles, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman, John D. Ray

Fuel Efficiency Automobile Test Publications

As part of the National Park Service’s Temporary Winter Use Plans Environmental Assessment, the University of Denver has been collecting in-use tailpipe emissions data from snowcoaches and snowmobiles in Yellowstone National Park. During the winter of 2006, using a portable emissions monitoring system, tailpipe data were collected from 10 snowcoaches and 2 four-stroke snowmobiles. These vehicles were operated over a standard route within the park, and the snowcoaches all carried identical passenger loads. These snowcoaches were newer in age with more advanced fuel management technology than those studied earlier, and average emissions were lower as a result (120, 1.7, and …


Signal To Noise Improvements In On-Road No, So2, And Nh3 Measurements Using A Multi-Component Classical Least Squares Fitting Approach (Presentation), Gary A. Bishop, Donald H. Stedman Jan 2008

Signal To Noise Improvements In On-Road No, So2, And Nh3 Measurements Using A Multi-Component Classical Least Squares Fitting Approach (Presentation), Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


A Decade Of On-Road Emissions Measurements, Gary A. Bishop, Donald H. Stedman Jan 2008

A Decade Of On-Road Emissions Measurements, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

A multi-year, on-road emission measurement program carried out in the cities of Chicago, IL, Denver, CO, Los Angeles, CA and Phoenix, AZ shows large, fuel specific tailpipe emissions reductions at all of the sites for carbon monoxide (CO), hydrocarbons (HC) and nitric oxide (NO). CO emissions decrease between 56% (Denver) and 71% (Chicago), HC emissions decrease between 27% (Phoenix) and 63% (Denver) and NO emissions have dropped between 48% (West LA) and 68% (Chicago). Three observed factors common to all of the sites are that the emission reductions are occurring in vehicles of all ages, that the influence of engine …


Calibrating Feat Instruments Without Gas Cylinders, Allison Peddle, Donald H. Stedman Jan 2008

Calibrating Feat Instruments Without Gas Cylinders, Allison Peddle, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 7, September 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman Jan 2007

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 7, September 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 6, January 2007, Gary A. Bishop, Donald H. Stedman Jan 2007

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 6, January 2007, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Portable Emission Measurements Of Snowcoaches And Snowmobiles In Yellowstone National Park, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman Jan 2007

Portable Emission Measurements Of Snowcoaches And Snowmobiles In Yellowstone National Park, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 6, November 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman Jan 2007

On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 6, November 2006, Gary A. Bishop, Ryan Stadtmuller, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


Fleet Vehicle Smoke Emissions As Measured By On-Road Remote Sensing Using Infrared Scattering: Years 1998 Through 2007, Jeffrey A. Caulfield, Gary A. Bishop, Donald H. Stedman Jan 2007

Fleet Vehicle Smoke Emissions As Measured By On-Road Remote Sensing Using Infrared Scattering: Years 1998 Through 2007, Jeffrey A. Caulfield, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


The Weekend Effect: The Science Suggests That We Are Embarking On An Expensive Policy Which Will Harm The Environment {Presentation}, Donald H. Stedman Jan 2006

The Weekend Effect: The Science Suggests That We Are Embarking On An Expensive Policy Which Will Harm The Environment {Presentation}, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 6, September 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2006

On-Road Remote Sensing Of Automobile Emissions In The Chicago Area: Year 6, September 2004, 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 Denver Area: Year 5, January 2005, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2006

On-Road Remote Sensing Of Automobile Emissions In The Denver Area: Year 5, January 2005, 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 West Los Angeles: Year 4, October 2005, Gary A. Bishop, Donald H. Stedman Jan 2006

On-Road Remote Sensing Of Automobile Emissions In West Los Angeles: Year 4, October 2005, 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 5, November 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2006

On-Road Remote Sensing Of Automobile Emissions In The Phoenix Area: Year 5, November 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


In-Use Emission Measurements Of Snowmobiles And Snowcoaches In Yellowstone National Park, Gary A. Bishop, Daniel A. Burgard, Thomas R. Dalton, Donald H. Stedman Jan 2006

In-Use Emission Measurements Of Snowmobiles And Snowcoaches In Yellowstone National Park, Gary A. Bishop, Daniel A. Burgard, Thomas R. Dalton, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Remote Sensing Of Automobile Emissions In The Omaha Area: Year 2, September 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman Jan 2005

On-Road Remote Sensing Of Automobile Emissions In The Omaha Area: Year 2, September 2004, Gary A. Bishop, Daniel A. Burgard, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.


On-Road Emissions In Asia Measured By Remote Sensing (Presentation), Donald H. Stedman, Gary A. Bishop Jan 2005

On-Road Emissions In Asia Measured By Remote Sensing (Presentation), Donald H. Stedman, Gary A. Bishop

Fuel Efficiency Automobile Test Publications

No abstract provided.


Vehicle Remote Sensing For Nitrogen Dioxide (Presentation), Thomas R. Dalton, Gary A. Bishop, Donald H. Stedman Jan 2005

Vehicle Remote Sensing For Nitrogen Dioxide (Presentation), Thomas R. Dalton, Gary A. Bishop, Donald H. Stedman

Fuel Efficiency Automobile Test Publications

No abstract provided.