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Full-Text Articles in Engineering

Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey Jan 2008

Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey

Civil and Environmental Engineering Faculty Publications and Presentations

Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment ...


New Particle Formation In The Front Range Of The Colorado Rocky Mountains, Micahel Boy, Thomas Karl, Andrew Turnipseed, Roy Lee Mauldin, Edward Kosciuch, James Greenberg, Jeff Rathbone, James Smith, Andreas Held, Kelley Barsanti, Alex Guenther Jan 2008

New Particle Formation In The Front Range Of The Colorado Rocky Mountains, Micahel Boy, Thomas Karl, Andrew Turnipseed, Roy Lee Mauldin, Edward Kosciuch, James Greenberg, Jeff Rathbone, James Smith, Andreas Held, Kelley Barsanti, Alex Guenther

Civil and Environmental Engineering Faculty Publications and Presentations

New particle formation is of interest because of its influence on the properties of aerosol population, and due to the possible contribution of newly formed particles to cloud condensation nuclei. Currently no conclusive evidence exists as to the mechanism or mechanisms of nucleation and subsequent particle growth. However, nucleation rates exhibit a clear dependence on ambient sulphuric acid concentrations and particle growth is often attributed to the condensation of organic vapours. A detailed study of new particle formation in the Front Range of the Colorado Rocky Mountains is presented here. Gas and particle measurement data for 32 days was analyzed ...


Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini Jan 2008

Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini

Civil and Environmental Engineering Faculty Publications and Presentations

With the increasing attention to finance issues relative to transit operation, a bus stop spacing model is generated with the aim at minimizing the operation cost without impact on transit accessibility. Two cost functions are considered in the model including passenger access cost and in-vehicle passenger stopping cost aiming at minimizing total cost. A bus route in Portland, Oregon, USA is examined as an example using Archived Bus Dispatch System (BDS) data provided by TriMet, the regional transit provider for the Portland, Oregon metropolitan area. Based on the optimization model, the theoretical optimized bus stop spacing is 930 feet comparing ...