Digital Commons Network^™

Ce-Qual-W2 Model And Model Set-Up, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

Conference presentation that provides background information on the CE-QUAL-W2 water modeling software, with examples of its use and instructions on set-up and application.

Nineteenth Century North American And Pacific Tidal Data: Lost Or Just Forgotten?, Stefan A. Talke, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Tide data are the oldest and longest oceanographic records and comprise one of the few tools for understanding, quantifying, and separating century-scale human and climate impacts on the coastal zone. Our archival research indicates that continuous measurements of tides began in 1844 in the western Atlantic, 1853 in the Eastern Pacific, and 1858 in the Western Pacific. At least 50 multiyear tide series existed by the year 1900. With few exceptions, however, these 19th and early 20th century measurements have not been analyzed in more than a century and have been forgotten and neglected by the scientific community. This article …

2012 Portland Metropolitan Region Transportation System Performance Report, Robert L. Bertini, Dean George, Matthew Downey

Civil and Environmental Engineering Faculty Publications and Presentations

Our transportation system is a key ingredient in the economy, quality of life and urban fabric of the Portland metropolitan area. It has been stated in the past that it is not possible to manage our transportation system tomorrow unless we understand how it is performing today. In this spirit, Portland State University has been working with regional and statewide partners to develop new capabilities to measure, monitor and track the performance of the transportation system in real time and using archived data sources. We believe that it is possible to leverage these disparate data sources toward providing better transportation …

Impacts Of Climate Change On The Seasonality Of Low Flows In 134 Catchments In The River Rhine Basin Using An Ensemble Of Bias-Corrected Regional Climate Simulations, Mehmet C. Demirel, Martijn Booij, Arjen Hoekstra

Civil and Environmental Engineering Faculty Publications and Presentations

The impacts of climate change on the seasonality of low flows were analysed for 134 sub-catchments covering the River Rhine basin upstream of the Dutch-German border. Three seasonality indices for low flows were estimated, namely the seasonality ratio (SR), weighted mean occurrence day (WMOD) and weighted persistence (WP). These indices are related to the discharge regime, timing and variability in timing of low flow events respectively. The three indices were estimated from: (1) observed low flows; (2) simulated low flows by the semi-distributed HBV model using observed climate as input; (3) simulated low flows using simulated inputs from seven combinations …

Transit Bus Fleet Age And Replacement Type Optimization, Miguel A. Figliozzi, Wei Feng, Jesse Boudart

Civil and Environmental Engineering Faculty Publications and Presentations

Due to recent budget and fiscal constraints, it is ever more imperative for transit agencies to manage their fleets in an optimal way. Fleet data have consistently shown that bus operational and maintenance (O&M) per-mile costs increase as buses age. From a purely economic perspective, there is a cost tradeoff between the lower O&M costs of newer fleets and their higher initial capital costs. This tradeoff has a significant impact on the optimal timing of purchase and replacement decisions. Utilizing realistic cost data and an optimization modeling framework, we analyze (a) the impact of purchase timing decisions on fleet per-mile …

Improving The Representation Of The Pedestrian Environment In Travel Demand Models, Phase I, Kelly J. Clifton, Patrick Allen Singleton, Christopher Devlin Muhs, Robert J. Schneider, Peter Lagerwey

Civil and Environmental Engineering Faculty Publications and Presentations

There is growing support for improvements to the quality of the walking environment, including more investments to promote pedestrian travel. Metropolitan planning organizations (MPOs) are improving regional travel demand forecasting models to better represent walking and bicycling and to expand the evaluative capacity of models to address policy-relevant issues like air quality, public health, and the smart allocation of infrastructure and other resources. This report describes an innovative, spatially disaggregate method to integrate walking activity into trip-based travel models. Using data for the Portland, OR, metropolitan area, the method applies trip generation at a new micro-scale spatial unit: a 264-foot-by-264-foot …

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, …

The Application Of Smart Phone, Weight-Mile Truck Data To Support Freight-Modeling, Performance Measures And Planning, Katherine E. Bell, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

Oregon is one of the few states that currently charge a commercial truck weight-mile tax (WMT). The Oregon Department of Transportation (ODOT) has developed a data-collection system – Truck Road Use Electronics (TRUE) – to simplify WMT collection. The TRUE system includes a smart phone application that collects and records Global Positioning System (GPS) data. The TRUE data has enormous advantages over GPS data used in previous research due to its level of geographic detail and the potential to also integrate trip origin and destination, vehicle class, and commodity-type data. This research evaluates the accuracy of the TRUE data and …

A Comparison Of Bicyclists’ Performance Characteristics At Urban, Suburban, And Dedicated Path Intersections In Oregon, Kirk Paulsen, Christopher M. Monsere, Sam R. Thompson, Miguel A. Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

This presentation provides an overview of the following research objectives

• To develop operational guidelines for timing and phasing of bicycle-specific traffic signals or modifications that can be made to existing signals to better accommodate bicycles.
• To develop engineering guidelines for the design of bicycle-specific traffic signals.

Definition And Properties Of Alternative Bus Service Reliability Measures At The Stop Level, Meead Saberi, Ali K. Zockaie, Wei Feng, Ahmed El-Geneidy

Civil and Environmental Engineering Faculty Publications and Presentations

The Transit Capacity and Quality of Service Manual (TCQSM) provides transit agencies with tools for measuring system performance at different levels of operation. Bus service reliability, one of the key performance measures, has become a major concern of both transit operators and users because it significantly affects user experience and service quality perceptions. The objective of this paper is to assess the existing reliability measures proposed by TCQSM and develop new ones at the bus stop level. The latter are not suggested as replacements for the existing measures; rather, they are complementary. Using empirical data from archived Bus Dispatch System …

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 …

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

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 …

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 …