Engineering Commons^™

Application Of The Coastal Storm Impulse (Cosi) Parameter To Predict Coastal Erosion, Robert Aaron Walker

Civil & Environmental Engineering Theses & Dissertations

A new coastal storm-strength parameter, the Coastal Storm Impulse (COSI) parameter, was introduced at the 2006 International Conference of Coastal Engineering (ICCE) in San Diego and further discussed at the ICCE 2008 in Hamburg. COSI is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. Both tropical storms (hurricanes) and extra-tropical storms (northeasters) can produce similar COSI parameters. Potential implications of such a storm classification system include the evaluation of potential coastal erosion and coastal infrastructure, as well as providing a universal storm strength indicator that is directly tied …

Using Micro-Simulation To Evaluate Transit Signal Priority For Lrt Operations In A Downtown Environment, Faisal Mahmud

Civil & Environmental Engineering Theses & Dissertations

Transit Signal Priority or TSP is an operational strategy that facilitates the movement of transit vehicles such as buses, light rail or streetcars, through traffic-signal controlled intersections. The benefits of TSP operations include improved schedule adherence and improved transit travel times with minimal impact to normal traffic operations. New advances in Global Positioning Systems, detection and communication, and control strategies have helped overcome many problems with early systems and increased interest in implementing TSP for Light Rail Transit (LRT) and other transit operations. The increased capabilities of these advanced systems have led to a dramatic increase in operational and planned …

A Study Of Passive Earth Pressure In Anisotropic Sand With Various Wall Movement Modes, Achmad Bakri Muhiddin

Civil & Environmental Engineering Theses & Dissertations

This study investigated the effect of anisotropy on passive pressure in sands by developing computer simulation utilizing FLAC code for plane strain condition. A series of wall movement modes was applied namely translation, rotation about a point below the wall, RBT, and rotation about a point above the wall, RTT.

From comparisons with other FLAC model in translation mode with isotropic material, the coefficients of passive pressure K_p were similar to each other except for some combinations of zero dilation, low wall friction, and high angle of internal friction ϕ. Dilation angle has less effect on K_p than …

The Influence Of Mechanical Circulation On Water Column Stability And Dissolved Oxygen In Stratified Lakes, Paal Engebrigtsen

Civil & Environmental Engineering Theses & Dissertations

Surface circulators have been used in wastewater and industrial lagoons for many years, but only recently have they been designed for lakes and reservoirs as a water quality management tool. Their relatively low capital investment and operational costs make them an attractive chemical free option for ameliorating the symptoms of eutrophication. Little research has been conducted on their effectiveness in impacting water quality. Today many lake managers are waiting for independent research on surface circulators' performance before installing such systems.

The Occoquan Reservoir was the primary site for a study conducted to examine the influence of surface circulation on water …

Route Change Decision Making By Hurricane Evacuees Facing Congestion, R. Michael Robinson, Asad Khattak

VMASC Publications

Successful evacuations of metropolitan areas require overcoming unexpected congestion that reduces traffic flows. Congestion may result from accidents, incidents, or other events that reduce road capacity. Traffic professionals and emergency managers may promote deviations from planned routes to bypass an area of congestion and speed mass exit. However, some route changes may actually reduce traffic flow rates, and in these cases decision makers may want to discourage use of alternate routes. By using results of a behavioral survey of potential hurricane evacuees, this study identifies variables associated with the decision to alter routes and also identifies frequently used information sources. …

Effluent Organic Nitrogen (Eon): Bioavailability And Photochemical And Salinity-Mediated Release, Deborah A. Bronk, Quinn N. Roberts, Marta P. Sanderson, Elizabeth A. Canuel, Patrick G. Hatcher, Rajaa Mesfioui, Katherine C. Filippino, Margaret R. Mulholland, Nancy G. Love

Chemistry & Biochemistry Faculty Publications

The goal of this study was to investigate three potential ways that the soluble organic nitrogen (N) fraction of wastewater treatment plant (WWTP) effluents, termed effluent organic N (EON), could contribute to coastal eutrophication - direct biological removal, photochemical release of labile compounds, and salinity-mediated release of ammonium (NH₄+). Effluents from two WWTPs were used in the experiments. For the bioassays, EON was added to water from four salinities (∼0 to 30) collected from the James River (VA) in August 2008, and then concentrations of N and phosphorus compounds were measured periodically over 48 h. Bioassay results, based …