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- Atmospheric physics (1)
- Bayesian statistical decision theory -- Applications to hydrology (1)
- Bridges -- Oregon -- Design and construction -- Evaluation -- Planning (1)
- Bridges -- Retrofitting -- Oregon -- Evaluation -- Planning (1)
- Columbia River (Or. and Wash.) -- Hydrodynamics (1)
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- Columbia River Estuary (Or. and Wash.) -- Environmental conditions (1)
- Earthquake hazard analysis -- Oregon -- Planning (1)
- Earthquake resistant design -- Oregon -- Evaluation -- Planning (1)
- Ems River Estuary (Germany and Netherlands) (1)
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- Estuaries -- Turbidity -- Mathematical models (1)
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- Freight and freightage -- Planning (1)
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- Ocean mixing -- Tropics -- Mathematical models (1)
- Oregon. Department of Transportation -- Safety -- Investigation (1)
- Particles (Nuclear physics) (1)
- Plumes (Fluid dynamics) (1)
- Remote sensing -- Columbia River (Or. and Wash.) (1)
- Sea level -- Climatic factors -- Pacific Ocean (1)
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Articles 1 - 12 of 12
Full-Text Articles in Engineering
Particle Resuspension In The Columbia River Plume Near Field, Emily Y. Spahn, Alexander R. Horner-Devine, Jonathan Nash, David A. Jay, Levi Kilcher
Particle Resuspension In The Columbia River Plume Near Field, Emily Y. Spahn, Alexander R. Horner-Devine, Jonathan Nash, David A. Jay, Levi Kilcher
Civil and Environmental Engineering Faculty Publications and Presentations
Measurements of suspended sediment concentration, velocity, salinity, and turbulent microscale shear in the near-field region of the Columbia River plume are used to investigate the mechanisms of sediment resuspension and entrainment into the plume. An east-west transect was occupied during spring and neap tide periods in August 2005 and May 2006, corresponding to low and high river discharge conditions, respectively. During the high-discharge period the plume is decoupled from the bottom, and fine sediment resuspended from the bottom does not leave the benthic boundary layer. The primary modes of sediment transport associated with the plume are advection of sediment from …
Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary
Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary
Civil and Environmental Engineering Faculty Publications and Presentations
The Oregon Department of Transportation and Portland State University evaluated the seismic vulnerability of state highway bridges in western Oregon. The study used a computer program called REDARS2 that simulated the damage to bridges within a transportation network. It predicted ground motions for a specific location and magnitude of earthquake, resulting bridge damage and the cost of the damage, as well as the cost to the public for traffic delays due to detours around damaged bridges. Estimated damage and delay costs were presented for major highways in the region.
An Overview Of The Odot Safety Investigations Manual, Christopher M. Monsere, Karen Dixon
An Overview Of The Odot Safety Investigations Manual, Christopher M. Monsere, Karen Dixon
Civil and Environmental Engineering Faculty Publications and Presentations
This presentation provides an overview of the ODOT Safety Investigations Manual. The objective of this manual is to function as a resource that will assist ODOT traffic investigators with highway safety project screening and evaluations.
A New Look At Richardson Number Mixing Schemes For Equatorial Ocean Modeling, Edward D. Zaron, James N. Moum
A New Look At Richardson Number Mixing Schemes For Equatorial Ocean Modeling, Edward D. Zaron, James N. Moum
Civil and Environmental Engineering Faculty Publications and Presentations
A reexamination of turbulence dissipation measurements from the equatorial Pacific shows that the turbulence diffusivities are not a simple function of the gradient Richardson number. A widely used mixing scheme, the K-profile parameterization, overpredicts the turbulent vertical heat flux by roughly a factor of 4 in the stably stratified region between the surface mixed layer and the Equatorial Undercurrent (EUC). Additionally, the heat flux divergence is of the incorrect sign in the upper 80 m. An alternative class of parameterizations is examined that expresses the mixing coefficients in terms of the large-scale kinetic energy, shear, and Richardson number. These representations …
Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin
Determining Azimuthal Variations In Frontal Froude Number From Sar Imagery, Jiayi Pan, David A. Jay, Hui Lin
Civil and Environmental Engineering Faculty Publications and Presentations
River plume fronts are the locus of strong mixing between plume and ambient coastal waters, contribute to coastal productivity, and exert a major impact on coastal ecosystems. The frontal Froude number Fr is an important parameter characterizing the frontal status with respect to both propagation and vertical mixing. In this study, we examine azimuthal variations in Fr using a new remote sensing method. We derive Fr from SAR image data on the basis of the SAR imaging theory and the mechanism of internal wave fission at front. This method is applied to a SAR image showing a front off the …
Vertical Boil Propagation From A Submerged Estuarine Sill, C. Chris Chickadel, Alexander R. Horner-Devine, Stefan A. Talke, Andrew T. Jessup
Vertical Boil Propagation From A Submerged Estuarine Sill, C. Chris Chickadel, Alexander R. Horner-Devine, Stefan A. Talke, Andrew T. Jessup
Civil and Environmental Engineering Faculty Publications and Presentations
Surface disruptions by boils during strong tidal flows over a rocky sill were observed in thermal infrared imagery collected at the Snohomish River estuary in Washington State. Locations of boil disruptions and boil diameters at the surface were quantified and are used to test an idealized model of vertical boil propagation. The model is developed as a two-dimensional approximation of a three-dimensional vortex loop, and boil vorticity is derived from the flow shear over the sill. Predictions of boil disruption locations were determined from the modeled vertical velocity, the sill depth, and the over-sill velocity. Predictions by the vertical velocity …
Practical Approximations To Quantify The Impact Of Time Windows And Delivery Sizes On Vmt Multi-Stop Tours, Miguel A. Figliozzi
Practical Approximations To Quantify The Impact Of Time Windows And Delivery Sizes On Vmt Multi-Stop Tours, Miguel A. Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
This paper studies approximations to the average length of Vehicle Routing Problems (VRP). The approximations are valuable for strategic and planning analysis of transportation and logistics problems. The research focus is on VRP with varying number of customers, demands, and locations. This modeling environment can be used in transport and logistics models that deal with a distribution center serving an area with daily variations in the demand. The routes are calculated daily based on what freight is available. New approximations and experimental settings are introduced. Average distance travelled is estimated as a function of the number of customers served and …
Evolution Of Tidal Amplitudes In The Eastern Pacific Ocean, David A. Jay
Evolution Of Tidal Amplitudes In The Eastern Pacific Ocean, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Global sea level (GSL) rise is well documented. However, changes in high waters, including the tidal contribution, are sometimes more relevant than GSL rise. Analysis of 34 long tidal records from the Eastern Pacific Ocean shows that K1 and M2 amplitudes (∣K₁∣ and ∣M₂∣) are increasing, except for ∣M2∣ in the Gulf of Panama. North of 18°N, ∣K1∣ and ∣M2∣ are both growing at 2.2% century⁻¹. The mean increase in total tidal amplitude (0.59 mmyr⁻¹) is less than the present GSL rise (1.7 mmyr⁻¹). However, mean sea level is nearly constant in the NE Pacific, so tidal evolution plays a …
The Potential Contribution Of Organic Salts To New Particle Growth, Kelley Barsanti, Peter H. Mcmurry, J. N. Smith
The Potential Contribution Of Organic Salts To New Particle Growth, Kelley Barsanti, Peter H. Mcmurry, J. N. Smith
Civil and Environmental Engineering Faculty Publications and Presentations
Field and lab measurements suggest that low-molecular weight (MW) organic acids and bases exist in accumulation and nucleation mode particles, despite their relatively high pure-liquid vapor pressures. The mechanism(s) by which such compounds contribute to the mass growth of existing aerosol particles and newly formed particles has not been thoroughly explored. One mechanism by which low- MW compounds may contribute to new particle growth is through the formation of organic salts. In this paper we use thermodynamic modeling to explore the potential for organic salt formation by atmospherically relevant organic acids and bases for two system types: one in which …
A Sequential Bayesian Approach For Hydrologic Model Selection And Prediction, Kuo-Lin Hsu, Hamid Moradkhani, Soroosh Sorooshian
A Sequential Bayesian Approach For Hydrologic Model Selection And Prediction, Kuo-Lin Hsu, Hamid Moradkhani, Soroosh Sorooshian
Civil and Environmental Engineering Faculty Publications and Presentations
When a single model is used for hydrologic prediction, it must be capable of estimating system behavior accurately at all times. Multiple-model approaches integrate several model behaviors and, when effective, they can provide better estimates than that of any single model alone. This paper discusses a sequential model fusion strategy that uses the Bayes rule. This approach calculates each model's transient posterior distribution at each time when a new observation is available and merges all model estimates on the basis of each model's posterior probability. This paper demonstrates the feasibility of this approach through case studies that fuse three hydrologic …
An Idealized Model And Systematic Process Study Of Oxygen Depletion In Highly Turbid Estuaries, Stefan A. Talke, Huib E. De Swart, Victor De Jonge
An Idealized Model And Systematic Process Study Of Oxygen Depletion In Highly Turbid Estuaries, Stefan A. Talke, Huib E. De Swart, Victor De Jonge
Civil and Environmental Engineering Faculty Publications and Presentations
The sensitivity of oxygen depletion in turbid estuaries to parameters like freshwater discharge, depth, and sediment availability is investigated using an idealized model. The model describes tidally averaged circulation and suspended sediment concentration (SSC), which are input into an advection–diffusion sink module of dissolved oxygen (DO). Based on the analysis of field data collected in the Ems estuary, the modeled oxygen depletion rates are proportional to SSC. The model is calibrated to the observed variation of DO with SSC and temperature. Modeled DO closely tracks changes to the estuarine turbidity zone (ETZ): increased channel depth, decreased freshwater discharge, and decreased …
Feedback Between Residual Circulations And Sediment Distribution In Highly Turbid Estuaries: An Analytical Model, Stefan A. Talke, Huib E. De Swart, H. M. Schuttelaars
Feedback Between Residual Circulations And Sediment Distribution In Highly Turbid Estuaries: An Analytical Model, Stefan A. Talke, Huib E. De Swart, H. M. Schuttelaars
Civil and Environmental Engineering Faculty Publications and Presentations
Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m4), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge. Salinity is assumed to be vertically well mixed, while the vertical concentration profile is assumed to result from a balance between a constant settling velocity and turbulent diffusive flux. Width and depth of the model estuary are held constant. Model results show that turbidity gradients enhance tidally averaged circulation upstream of the estuarine turbidity maximum (ETM), …