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Portland State University

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Articles 121 - 150 of 169

Full-Text Articles in Environmental Engineering

Increasing Storm Tides In New York Harbor, 1844–2013, Stefan A. Talke, Philip M. Orton, David A. Jay May 2014

Increasing Storm Tides In New York Harbor, 1844–2013, Stefan A. Talke, Philip M. Orton, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Three of the nine highest recorded water levels in the New York Harbor region have occurred since 2010 (March 2010, August 2011, and October 2012), and eight of the largest twenty have occurred since 1990. To investigate whether this cluster of high waters is a random occurrence or indicative of intensified storm tides, we recover archival tide gauge data back to 1844 and evaluate the trajectory of the annual maximum storm tide. Approximately half of long-term variance is anticorrelated with decadal-scale variations in the North Atlantic Oscillation, while long-term trends explain the remainder. The 10 year storm tide has increased …


Small-Scale Minimal-Maintenance Anaerobic Digestion Of Food Waste For Solids Reduction And Methane Production: Feasibility Study, Leland C. Scantlebury Apr 2014

Small-Scale Minimal-Maintenance Anaerobic Digestion Of Food Waste For Solids Reduction And Methane Production: Feasibility Study, Leland C. Scantlebury

Civil and Environmental Engineering Undergraduate Honors Theses

Six gallons of food waste was anaerobically digested for 76 days in two small-scale digesters sitting by a lab window. The main difference, besides waste sources, of these digesters was substrate processing: chopping versus blending. An effort was made to minimize the maintenance of the digesters, however, after 45 days of overly acidic (pH


Benchtop Minimal-Intervention Anaerobic Digestion Of Vegetarian Food Waste For Ph And Methane Production: Conceivability And Control Study, Emily J. Heleva-Ponaski Apr 2014

Benchtop Minimal-Intervention Anaerobic Digestion Of Vegetarian Food Waste For Ph And Methane Production: Conceivability And Control Study, Emily J. Heleva-Ponaski

Civil and Environmental Engineering Undergraduate Honors Theses

Cities around the world transport large quantities of waste to landfills at a great expense to their residents, infrastructures, and environments. The objective of this study was to run an anaerobic food waste digester with minimal interference or maintenance. One specific goal of this research was to evaluate the relationship between anaerobic food waste and pH. Two benchop digesters were started with vegetarian food waste collected from the Portland State University campus. Measurements were collected over the course of the digestion process. Due to low pH and lack of biogas production, the digesters were buffered with sodium carbonate and seeded …


Time-Variable Refraction Of The Internal Tide At The Hawaiian Ridge, Edward D. Zaron, Gary D. Egbert Feb 2014

Time-Variable Refraction Of The Internal Tide At The Hawaiian Ridge, Edward D. Zaron, Gary D. Egbert

Civil and Environmental Engineering Faculty Publications and Presentations

The interaction of the dominant semidiurnal M2 internal tide with the large-scale subtidal flow is examined in an ocean model by propagating the tide through an ensemble of background fields in a domain centered on the Hawaiian Ridge. The background fields are taken from the Simple Ocean Data Assimilation (SODA) ocean analysis, at 2-month intervals from 1992 through 2001. Tides are computed with the Primitive Equation Z-coordinate Harmonic Analysis of Tides (PEZ-HAT) model by 14-day integrations using SODA initial conditions and M2 tidal forcing. Variability of the tide is found to occur primarily as the result of propagation through …


The Small Volume Autonomous Water Sampler (Svaws): An Innovative, Cost- Effective, Adaptable Protocol, Nicholas B. Fitzgerald Jan 2014

The Small Volume Autonomous Water Sampler (Svaws): An Innovative, Cost- Effective, Adaptable Protocol, Nicholas B. Fitzgerald

Dissertations and Theses

As of 2007, U.S. pesticide use stood at 1.1 billion pounds with 80% of all usage in agriculture. Such realities pose a potentially dangerous threat to our surface water bodies. This research provides a detailed analysis of the design, operation and field testing of a prototype water sampler, the Small Volume Autonomous Water Sampler (SVAWS). The research includes a discussion of the design and construction of the SVAWS. Seven USGS employees operated the SVAWS in a number of different states and conditions in order to collect samples for pesticide analysis. Field-testing outcomes of the SVAWS were measured through a Participant …


Wider Dissemination Of Household Travel Survey Data Using Geographical Perturbation Methods, Kelly J. Clifton, Steven R. Gehrke Jan 2014

Wider Dissemination Of Household Travel Survey Data Using Geographical Perturbation Methods, Kelly J. Clifton, Steven R. Gehrke

Civil and Environmental Engineering Faculty Publications and Presentations

Public agencies spend vast amounts of money collecting information about passenger travel in household travel surveys. These data are valuable for the rich and detailed information they provide, which contribute to regional and statewide travel demand models. These data have utility beyond travel demand modeling in their application to transportation policy and travel behavior research. As the demand on these data increase, so have the quantity of information collected. Detailed geospatial referencing of the home, work and other travel destinations are common practice and permit the integration with other spatially archived data sources, such as land use characteristics, transportation system …


Turbulent Kinetic Energy And Coherent Structures In A Tidal River, Stefan A. Talke, Alexander R. Horner-Devine, C. Chris Chickadel, Andrew T. Jessup Dec 2013

Turbulent Kinetic Energy And Coherent Structures In A Tidal River, Stefan A. Talke, Alexander R. Horner-Devine, C. Chris Chickadel, Andrew T. Jessup

Civil and Environmental Engineering Faculty Publications and Presentations

We investigate the relationship between turbulence statistics and coherent structures (CS) in an unstratified reach of the Snohomish River estuary using in situ velocity measurements and surface infrared (IR) imaging. Sequential IR images are used to estimate surface flow characteristics via a particle-image-velocimetry (PIV) technique, and are conditionally sampled to delineate the surface statistics of bottom-generated CS, or boils. In the water column, we find that turbulent kinetic energy (TKE) production exceeds dissipation near the bed but is less than dissipation in the midwater column and that TKE flux divergence closes a significant portion of the measured imbalance. The surface …


Research Project Work Plan For Impact Of Cascadia Subduction Zone Earthquake On The Seismic Evaluation Criteria Of Bridges, Peter Dusicka Dec 2013

Research Project Work Plan For Impact Of Cascadia Subduction Zone Earthquake On The Seismic Evaluation Criteria Of Bridges, Peter Dusicka

Civil and Environmental Engineering Faculty Publications and Presentations

The goal of this project is to provide ODOT with the best rational estimate of ground acceleration values for designing new and retrofitting existing bridges. The objectives are to:

  • evaluate the hazard by contrasting the acceleration values from individual CSZ events to PSHA values
  • provide experimental evidence of damage difference under longer duration shaking expected from CSZ event


Evidence Supporting Treatment Practice Based Delineation Of Stormwater Runoff Zones, Jacob J. Gorski Oct 2013

Evidence Supporting Treatment Practice Based Delineation Of Stormwater Runoff Zones, Jacob J. Gorski

Dissertations and Theses

Particles mobilized by stormwater negatively affect receiving surface waters. Stormwater best management practices (BMPs) can reduce solids along with associated pollutants in runoff but engineers and environmental managers have been long vexed by the problem of choosing the optimal BMP for a given situation. A common BMP process for solids removal is sedimentation. This thesis addresses the question of whether the effectiveness (and thus choice) of a sedimentation device can be estimated (and thus optimized) from the particle size properties of runoff, which, in turn, could be associated with specific runoff zones or land uses. Presented here is a series …


Characterization Of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas Chromatography With Time Of Flight Mass Spectrometry (Gc×Gc/Tofms), Melissa Jordan Roskamp Sep 2013

Characterization Of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas Chromatography With Time Of Flight Mass Spectrometry (Gc×Gc/Tofms), Melissa Jordan Roskamp

Dissertations and Theses

The oxidation of volatile organic compounds (VOCs) plays a role in both regional and global air quality through the formation of secondary organic aerosols (SOA). More than 1000TgC/yr of non-methane VOCs are emitted from biogenic sources (significantly greater than from anthropogenic sources). Despite this magnitude and potential importance for air quality, the body of knowledge around the identities, quantities and oxidation processes of these compounds is still incomplete (e.g., Goldstein & Galbally, 2007; Robinson et al., 2009). Two-dimensional gas chromatography paired with time-of-flight mass spectrometry (GC×GC/TOFMS) is a powerful analytical technique which is explored here for its role in better …


Rooftop Pv Impacts On Fossil Fuel Electricity Generation And Co2 Emissions In The Pacific Northwest, Daniel Albert Weiland Aug 2013

Rooftop Pv Impacts On Fossil Fuel Electricity Generation And Co2 Emissions In The Pacific Northwest, Daniel Albert Weiland

Dissertations and Theses

This thesis estimates the impacts of rooftop photovoltaic (PV) capacity on electricity generation and CO2 emissions in America's Pacific Northwest. The region's demand for electricity is increasing at the same time that it is attempting to reduce its greenhouse gas emissions. The electricity generated by rooftop PV capacity is expected to displace electricity from fossil fueled electricity generators and reduce CO2 emissions, but when and how much? And how can this region maximize and focus the impacts of additional rooftop PV capacity on CO2 emissions? To answer these questions, an hourly urban rooftop PV generation profile for 2009 was created …


A Novel Approach To Flow Estimation In Tidal Rivers, Hamed Moftakhari Rostamkhani, David A. Jay, Stefan A. Talke, Tobias Kukulka, Peter D. Bromirski Aug 2013

A Novel Approach To Flow Estimation In Tidal Rivers, Hamed Moftakhari Rostamkhani, David A. Jay, Stefan A. Talke, Tobias Kukulka, Peter D. Bromirski

Civil and Environmental Engineering Faculty Publications and Presentations

Reliable estimation of river discharge to the ocean from large tidal rivers is vital for water resources management and climate analyses. Due to the difficulties inherent in measuring tidal-river discharge, flow records are often limited in length and/or quality and tidal records often predate discharge records. Tidal theory indicates that tides and river discharge interact through quadratic bed friction, which diminishes and distorts the tidal wave as discharge increases. We use this phenomenon to develop a method of estimating river discharge for time periods with tidal data but no flow record. Employing sequential 32 day harmonic analyses of tidal properties, …


Assessment Of Solar Photovoltaic Technologies Using Multiple Perspectives And Hierarchical Decision Modeling, Nasir Jamil Sheikh Apr 2013

Assessment Of Solar Photovoltaic Technologies Using Multiple Perspectives And Hierarchical Decision Modeling, Nasir Jamil Sheikh

Dissertations and Theses

The objective of this research is to build a decision model for a comprehensive assessment of solar photovoltaic technologies using multiple perspectives. These perspectives include: social, technological, economic, environmental, and political (STEEP) with each perspective consisting of multiple criteria. Hierarchical decision modeling and expert judgment quantification are used to provide the relative ranking of the perspectives and criteria. Such modeling is effective in addressing technology evaluations with competing and contrasting perspectives and criteria where both quantitative and qualitative measurements are represented. The model is then operationalized by constructing desirability functions for each criterion. The combined results provide an overall numerical …


Adaptation Of Classical Tidal Harmonic Analysis To Nonstationary Tides, With Application To River Tides, Pascal Matte, David A. Jay, Edward D. Zaron Mar 2013

Adaptation Of Classical Tidal Harmonic Analysis To Nonstationary Tides, With Application To River Tides, Pascal Matte, David A. Jay, Edward D. Zaron

Civil and Environmental Engineering Faculty Publications and Presentations

One of the most challenging areas in tidal analysis is the study of nonstationary signals with a tidal component, as they confront both current analysis methods and dynamical understanding. A new analysis tool has been developed, NS_TIDE, adapted to the study of nonstationary signals, in this case, river tides. It builds the nonstationary forcing directly into the tidal basis functions. It is implemented by modification of T_TIDE; however, certain concepts, particularly the meaning of a constituent and the Rayleigh criterion, are redefined to account for the smearing effects on the tidal spectral lines by nontidal energy. An error estimation procedure …


Predicting Landslides In Real Time, Michael J. Olsen Mar 2013

Predicting Landslides In Real Time, Michael J. Olsen

TREC Project Briefs

The Oregon Department of Transportation, or ODOT, has an ongoing struggle to maintain public highways against earth movements such as erosion, earthquakes and landslides. An earthquake or landslide can close down a road for days, while highway workers fight to keep supply lines open and repair the damage. Particularly along Oregon’s coastal roads with high sea cliffs, these natural processes are a constant threat to transportation infrastructure. The damage caused by gradual erosion is typically not detectable until there is a landslide or other disaster, costing the state considerable time and money to repair. New technology has the potential to …


Examining Consumer Behavior And Travel Choices, Kelly J. Clifton, Christopher Devlin Muhs, Sara Morrissey, Tomás Morrissey, Kristina Marie Currans, Chloe Ritter Feb 2013

Examining Consumer Behavior And Travel Choices, Kelly J. Clifton, Christopher Devlin Muhs, Sara Morrissey, Tomás Morrissey, Kristina Marie Currans, Chloe Ritter

Civil and Environmental Engineering Faculty Publications and Presentations

This study represents a first attempt to answer a few of the questions that have arisen concerning multimodal transportation investments and the impacts of mode shifts on the business community. This research aims to merge the long history of scholarly work that examines the impacts of the built environment on non-work travel with the relatively new interest in consumer spending by mode of travel. This empirical study of travel choices and consumer spending across 89 businesses in the Portland metropolitan area shows there are important differences between the amounts customers spend on average at various businesses by their mode of …


Effects Of Molecular Structure Of The Oxidation Products Of Reactive Atmospheric Hydrocarbons On The Formation Of Secondary Organic Particulate Matter, Including The Effects Of Water, Negar Niakan Jan 2013

Effects Of Molecular Structure Of The Oxidation Products Of Reactive Atmospheric Hydrocarbons On The Formation Of Secondary Organic Particulate Matter, Including The Effects Of Water, Negar Niakan

Dissertations and Theses

Organic aerosols have significant effects on human health, air quality and climate. Secondary organic aerosols (SOA) are produced by the oxidation of primary-volatile organic compounds (VOC). For example, α-pinene reacts with oxidants such as hydroxyl radical (OH), ozone (O3), and nitrate radical (NO3), accounting for a significant portion of total organic aerosol in the atmosphere. Experimental studies have shown that the oxidation process between α-pinene and ozone has the most significant impact in the formation of SOA (Hoffmann et al., 1997). Most of the models used to predict SOA formation, however, are limited in that they …


Model For Acid-Base Chemistry In Nanoparticle Growth (Mabnag), Taina Yli-Juuti, Kelley Barsanti, L. Hildebrandt Ruiz, Antti-Jussi Kieloaho, U. Makkonen, Tuukka Petäjä, Taina Ruuskanen, Markku Kulmala, Ilona Riipinen Jan 2013

Model For Acid-Base Chemistry In Nanoparticle Growth (Mabnag), Taina Yli-Juuti, Kelley Barsanti, L. Hildebrandt Ruiz, Antti-Jussi Kieloaho, U. Makkonen, Tuukka Petäjä, Taina Ruuskanen, Markku Kulmala, Ilona Riipinen

Civil and Environmental Engineering Faculty Publications and Presentations

Climatic effects of newly-formed atmospheric secondary aerosol particles are to a large extent determined by their condensational growth rates. However, all the vapours condensing on atmospheric nanoparticles and growing them to climatically relevant sizes are not identified yet and the effects of particle phase processes on particle growth rates are poorly known. Besides sulfuric acid, organic compounds are known to contribute significantly to atmospheric nanoparticle growth. In this study a particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth) was developed to study the effect of salt formation on nanoparticle growth, which has been proposed as a potential …


Positive Matrix Factorization Of Pm2.5 - Eliminating The Effects Of Gas/Particle Partitioning Of Semivolatile Organic Compounds, Mingjie Xie, Kelley Barsanti, Michael P. Hannigan, Steven J. Dutton, Sverre Vedal Jan 2013

Positive Matrix Factorization Of Pm2.5 - Eliminating The Effects Of Gas/Particle Partitioning Of Semivolatile Organic Compounds, Mingjie Xie, Kelley Barsanti, Michael P. Hannigan, Steven J. Dutton, Sverre Vedal

Civil and Environmental Engineering Faculty Publications and Presentations

Gas-phase concentrations of semi-volatile organic compounds (SVOCs) were calculated from gas/particle (G/P) partitioning theory using their measured particle-phase concentrations. The particle-phase data were obtained from an existing filter measurement campaign (27 January 2003-2 October 2005) as a part of the Denver Aerosol Sources and Health (DASH) study, including 970 observations of 71 SVOCs (Xie et al., 2013). In each compound class of SVOCs, the lighter species (e.g. docosane in n-alkanes, fluoranthene in PAHs) had higher total concentrations (gas + particle phase) and lower particle-phase fractions. The total SVOC concentrations were analyzed using positive matrix factorization (PMF). Then the results were …


Analyzing Experimental Data And Model Parameters: Implications For Predictions Of Soa Using Chemical Transport Models, Kelley Barsanti, Annmarie G. Carlton, Serena H. Chung Jan 2013

Analyzing Experimental Data And Model Parameters: Implications For Predictions Of Soa Using Chemical Transport Models, Kelley Barsanti, Annmarie G. Carlton, Serena H. Chung

Civil and Environmental Engineering Faculty Publications and Presentations

Despite critical importance for air quality and climate predictions, accurate representation of secondary organic aerosol (SOA) formation remains elusive. An essential addition to the ongoing discussion of improving model predictions is an acknowledgement of the linkages between experimental conditions, parameter optimization and model output, as well as the linkage between empirically-derived partitioning parameters and the physicochemical properties of SOA they represent in models. In this work, a "best available" set of SOA modeling parameters is selected by comparing predicted SOA yields and mass concentrations with observed yields and mass concentrations from a comprehensive list of published smog chamber studies. Evaluated …


Characterization Of Nano-Scale Aluminum Oxide Transport Through Porous Media, Sasha Norien Norwood Jan 2013

Characterization Of Nano-Scale Aluminum Oxide Transport Through Porous Media, Sasha Norien Norwood

Dissertations and Theses

Land application of biosolids has become common practice in the United States as an alternative to industrial fertilizers. Although nutrient rich, biosolids have been found to contain high concentrations of emerging contaminants (e.g. pharmaceuticals, personal care products) while containing a significant fraction of inorganic nano-scale colloidal materials such as oxides of iron, titanium, and aluminum.

Given their reactivity and small size, there are many questions concerning the potential migration of these nano-sized colloidal materials through the soil column and into our surface and groundwater bodies. Transport of emerging pollutants of concern through the soil column, at minimum, is impacted by …


Real-Time Change And Damage Detection Of Landslides And Other Earth Movements Threatening Public Infrastructure, Michael J. Olsen, Shawn Butcher, Evon P. Silvia Mar 2012

Real-Time Change And Damage Detection Of Landslides And Other Earth Movements Threatening Public Infrastructure, Michael J. Olsen, Shawn Butcher, Evon P. Silvia

TREC Final Reports

Geologic hazards such as coastal erosion, landslides, seismic loading, etc. constantly threaten public highway construction and maintenance. Repeat surveys using terrestrial laser scanning (TLS, ground-based LiDAR) enable rapid 3D data acquisition to map, see, analyze, and understand the processes generating such problems. Previously, change detection and analysis between scan surveys was conducted during post-processing upon return to the office, instead of while collecting data in the field. Change detection in the field improves the effectiveness and efficiency of the field investigation. We have developed a new algorithm that quickly geo-references scans upon field acquisition and simultaneously performs change detection by …


Strength And Fatigue Of Three Glass Fiber Reinforced Composite Bridge Decks With Mechanical Deck To Stringer Connections, Andrew Gleason, Peter Dusicka Feb 2012

Strength And Fatigue Of Three Glass Fiber Reinforced Composite Bridge Decks With Mechanical Deck To Stringer Connections, Andrew Gleason, Peter Dusicka

Civil and Environmental Engineering Faculty Publications and Presentations

Replacement of the steel grating deck on the lift span of the Morrison Bridge in Portland, OR, will utilize glass fiber reinforced polymer (FRP) panels to address ongoing maintenance issues of the deteriorated existing deck, improve driver safety and introduce bridge water runoff treatment. This report outlines the testing methods and results of an experimental program aimed primarily at evaluating a new open cell deck. While most FRP panels are connected via shear studs that are grouted within isolated pockets, the panels in this case were bolted directly to the steel stringers. Two different FRP deck options were evaluated for …


Tsunami Hydrodynamics In The Columbia River, Harry Yeh, Elena Tolkova, David A. Jay, Stefan A. Talke, Hermann Fritz Jan 2012

Tsunami Hydrodynamics In The Columbia River, Harry Yeh, Elena Tolkova, David A. Jay, Stefan A. Talke, Hermann Fritz

Civil and Environmental Engineering Faculty Publications and Presentations

On 11 March 2011, the Tohoku Tsunami overtopped a weir and penetrated 49 km up the Kitakami River, the fourth largest river in Japan. Similarly, the 2010 Chile tsunami propagated at least 15 km up the Maule River. In the Pacific Northwest of the United States, large tsunamis have occurred along the Cascadia subduction zone, most recently the 'orphan tsunami' of 1700 (Atwater et al.). The expected future occurrence of a Cascadia tsunami and its penetration into the Lower Columbia River became the subject of “the Workshop on Tsunami Hydrodynamics in a Large River” held in Corvallis, Oregon, 2011. We …


Identification Of The Biogenic Compounds Responsible For Size-Dependent Nanoparticle Growth, Paul M. Winkler, John Ortega, Thomas Karl, Luca Cappellin, Hans R. Friedli, Kelley Barsanti, Peter H. Mcmurry, James N. Smith Jan 2012

Identification Of The Biogenic Compounds Responsible For Size-Dependent Nanoparticle Growth, Paul M. Winkler, John Ortega, Thomas Karl, Luca Cappellin, Hans R. Friedli, Kelley Barsanti, Peter H. Mcmurry, James N. Smith

Civil and Environmental Engineering Faculty Publications and Presentations

The probability that freshly nucleated nanoparticles can survive to become cloud condensation nuclei is highly sensitive to particle growth rates. Much of the growth of newly formed ambient nanoparticles can be attributed to oxidized organic vapors originating from biogenic precursor gases. In this study we investigated the chemical composition of size-selected biogenic nanoparticles in the size range from 10 to 40 nm. Particles were formed in a flow tube reactor by ozonolysis ofα-pinene and analyzed with a Thermal Desorption Chemical Ionization Mass Spectrometer. While we found similar composition in 10 and 20 nm particles, the relative amounts of …


Climate Change Impact Assessment For Surface Transportation In The Pacific Northwest And Alaska, John Macarthur, Philip Mote, Miguel A. Figliozzi, Jason Ideker, Ming Lee Jan 2012

Climate Change Impact Assessment For Surface Transportation In The Pacific Northwest And Alaska, John Macarthur, Philip Mote, Miguel A. Figliozzi, Jason Ideker, Ming Lee

Civil and Environmental Engineering Faculty Publications and Presentations

The states in the Pacific Northwest and Alaska region share interconnected transportation networks for people, goods, and services that support the regional economy, mobility, and human safety. Regional weather has and will continue to affect the physical condition and serviceability of these networks, yet the nature of climate changes and their potential impacts on the regional transportation system and its use are very poorly understood. The world’s leading climate scientists, such as the Intergovernmental Panel for Climate Change, have reached consensus that global climate changes are being observed and will continue into the future, particularly increasing temperatures. Given this fact, …


An Empirical Study Of Particulate Matter Exposure For Transit Users At Bus Stop Shelters, Adam Moore Jan 2012

An Empirical Study Of Particulate Matter Exposure For Transit Users At Bus Stop Shelters, Adam Moore

Dissertations and Theses

Congested traffic corridors in dense urban areas are key contributors to the degradation of urban air quality. While waiting at bus stops, transit patrons may be exposed to greater amounts of vehicle-based pollution, including particulate matter, due to their proximity to the roadway. Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations. This thesis provides a unique contribution to roadside air quality studies and presents an innovative method for the consideration of bus shelter placement. Exposure to roadside pollutants is estimated for transit riders waiting at three-sided bus stop …


Refining Greenstep: Impacts Of Vehicle Technologies And Its/Operational Improvements On Travel Speed And Fuel Consumption Curves, Kelly Clifton, Alexander Y. Bigazzi Nov 2011

Refining Greenstep: Impacts Of Vehicle Technologies And Its/Operational Improvements On Travel Speed And Fuel Consumption Curves, Kelly Clifton, Alexander Y. Bigazzi

Civil and Environmental Engineering Faculty Publications and Presentations

This report describes analysis undertaken to establish a method for incorporating traffic operations and ITS strategies into the GreenSTEP model. We first discuss operations impacts on fuel economy and delay from the literature. Then, an investigation of delay adjustments in GreenSTEP shows that different methods of representing delay changes lead to similar (and small) impacts on fuel economy. From this result we establish average speed adjustment by congestion level as the preferred method for incorporating delay effects from operations improvements. An investigation of aggregate traffic operations impacts produces estimates of base speeds without operations improvements, maximum speeds with full operational …


Infrared-Based Measurements Of Velocity, Turbulent Kinetic Energy, And Dissipation At The Water Surface In A Tidal River, C. Chris Chickadel, Stefan A. Talke, Alexander R. Horner-Devine, Andrew T. Jessup Jan 2011

Infrared-Based Measurements Of Velocity, Turbulent Kinetic Energy, And Dissipation At The Water Surface In A Tidal River, C. Chris Chickadel, Stefan A. Talke, Alexander R. Horner-Devine, Andrew T. Jessup

Civil and Environmental Engineering Faculty Publications and Presentations

Thermal infrared (IR) based particle image velocimetry (PIV) is used to measure the evolution of velocity, turbulent kinetic energy (TKE), and the TKE dissipation rate at the water surface in the tidally influenced Snohomish River. Patterns of temperature variability in the IR imagery arise from disruption of the cool skin layer and are used to estimate the 2D velocity field. Comparisons of IR based PIV mean velocity made against a collocated acoustic velocimeter demonstrate high correlation (r2 > 0.9). Over a tidal period, surface TKE computed from the IR velocity varies from 10-4 J·kg-1 to 3x10-3 J·kg-1, with an average difference …


Circulation, Sediment Concentration And Oxygen Depletion In The Tidal Ems River, Stefan A. Talke, Huib E. De Swart Jan 2011

Circulation, Sediment Concentration And Oxygen Depletion In The Tidal Ems River, Stefan A. Talke, Huib E. De Swart

Civil and Environmental Engineering Faculty Publications and Presentations

We present measurements which show that the tidal Ems River in Germ any is extremely muddy over a 30 km + turbid zone, with fluid mud o f 1-2 m thickness covering the bed with suspended sediment concentrations (SSC) o f greater than 50 kg.m-3. Moreover, we show that these elevated SSC contain large quantities of organic material which deplete dissolved oxygen (DO) and produce summertime hypoxic zones. Using mathematical modeling, we develop simplified representations o f the estuary physics that reproduce the tidally-averaged circulation, SSC distribution, and oxygen depletion. These models show that SSC and oxygen concentrations …