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Articles 61 - 90 of 424
Full-Text Articles in Civil and Environmental Engineering
Modeling Cyanotoxin Production, Fate, And Transport In Surface Water Bodies Using Ce-Qual-W2, Bernadel Rose Hintz Garstecki, Scott A. Wells
Modeling Cyanotoxin Production, Fate, And Transport In Surface Water Bodies Using Ce-Qual-W2, Bernadel Rose Hintz Garstecki, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Cyanobacteria are frequently associated with forming toxic blooms. The toxins produced by cyanobacteria, cyanotoxins, are harmful to both humans and animals. Rising temperatures due to global climate change are expected to increase the occurrence of cyanobacteria, and it is vital that we protect our drinking water supplies and natural water resources. Modeling the production, fate, and transport of these toxins is an important step in limiting exposure to them and evaluating management strategies to mitigate their impact. The research provided here offers an overview of some of the main cyanotoxins of concern and presents preliminary models for the transport and …
Impacts Of A Cascadia Subduction Zone Earthquake On Water Levels And Wetlands Of The Lower Columbia River And Estuary, M. W. Brand, Heida Diefenderfer, J. E. O’Connor, Amy B. Borde, D. A. Jay, Aqeel Al-Bahadily, M. Mckeon, S. A. Talke
Impacts Of A Cascadia Subduction Zone Earthquake On Water Levels And Wetlands Of The Lower Columbia River And Estuary, M. W. Brand, Heida Diefenderfer, J. E. O’Connor, Amy B. Borde, D. A. Jay, Aqeel Al-Bahadily, M. Mckeon, S. A. Talke
Civil and Environmental Engineering Faculty Publications and Presentations
Subsidence after a subduction zone earthquake can cause major changes in estuarine bathymetry. Here, we quantify the impacts of earthquake-induced subsidence on hydrodynamics and habitat distributions in a major system, the lower Columbia River Estuary, using a hydrodynamic and habitat model. Model results indicate that coseismic subsidence increases tidal range, with the smallest changes at the coast and a maximum increase of ∼10% in a region of topographic convergence. All modeled scenarios reduce intertidal habitat by 24%–25% and shifts ∼93% of estuarine wetlands to lower-elevation habitat bands. Incorporating dynamic effects of tidal change from subsidence yields higher estimates of remaining …
Damage Tracking In Laboratory Reinforced Concrete Bridge Columns Under Reverse-Cyclic Loading Using Fusion-Based Imaging, Sina Mehdinia, A K M Golam Murtuz, Thomas Schumacher, Peter Dusicka
Damage Tracking In Laboratory Reinforced Concrete Bridge Columns Under Reverse-Cyclic Loading Using Fusion-Based Imaging, Sina Mehdinia, A K M Golam Murtuz, Thomas Schumacher, Peter Dusicka
Civil and Environmental Engineering Faculty Publications and Presentations
Fusion-based imaging using ground-penetrating radar (GPR) and ultrasonic echo array (UEA) was employed to track damage progression in the columns of two full-scale reinforced concrete (RC) bridge column-footing subassembly laboratory specimens. The specimens had different lap-splice detailing and were subjected to reverse-cyclic lateral loading simulating a subduction zone earthquake. GPR and UEA scans were performed on the east and west faces of the columns at select ductility levels. Reconstructed images were obtained using the extended total focusing method (XTFM) and fused using a wavelet-based technique. Composite images of each column's interior were created by merging the images from both sides. …
Global Water Level Variability Observed After The Hunga Tonga-Hunga Ha’Apai Volcanic Tsunami Of 2022, Adam Thomas Devlin, David A. Jay, Stefan Talke, Jiayi Pan
Global Water Level Variability Observed After The Hunga Tonga-Hunga Ha’Apai Volcanic Tsunami Of 2022, Adam Thomas Devlin, David A. Jay, Stefan Talke, Jiayi Pan
Civil and Environmental Engineering Faculty Publications and Presentations
The eruption of the Hunga Tonga-Hunga Ha'apai volcano on 15 January 2022 provided a rare opportunity to understand global tsunami impacts of explosive volcanism and to evaluate future hazards, including dangers from “volcanic meteotsunamis” (VMTs) induced by the atmospheric shock waves that followed the eruption. The propagation of the volcanic and marine tsunamis was analyzed using globally distributed 1 min measurements of air pressure and water level (WL) (from both tide gauges and deep-water buoys). The marine tsunami propagated primarily throughout the Pacific, reaching nearly 2 m at some locations, though most Pacific locations recorded maximums lower than 1 m. …
Warming Of The Columbia River, 1853 To 2018, Malia Hanae Scott, Stefan Talke, David Jay, Heida Diefenderfer
Warming Of The Columbia River, 1853 To 2018, Malia Hanae Scott, Stefan Talke, David Jay, Heida Diefenderfer
Civil and Environmental Engineering Faculty Publications and Presentations
Water temperature is a critical ecological indicator; however, few studies have statistically modeled century-scale trends in riverine or estuarine water temperature, or their cause. Here, we recover, digitize, and analyze archival temperature measurements from the 1850s onward to investigate how and why water temperatures in the lower Columbia River are changing. To infill data gaps and explore changes, we develop regression models of daily historical Columbia River water temperature using time-lagged river flow and air temperature as the independent variables. Models were developed for 3 time periods (mid-19 th , mid-20 th , and early 21 st century), using archival …
Numerical Modeling Of A Pile-Supported Wharf Subjected To Liquefaction-Induced Lateral Ground Deformations, Milad Souri, Arash Khosravifar, Stephen Dickenson, Nason Mccullough, Scott Schlechter
Numerical Modeling Of A Pile-Supported Wharf Subjected To Liquefaction-Induced Lateral Ground Deformations, Milad Souri, Arash Khosravifar, Stephen Dickenson, Nason Mccullough, Scott Schlechter
Civil and Environmental Engineering Faculty Publications and Presentations
Fully-coupled nonlinear dynamic analysis is increasingly used for assessing the seismic performance of pile-supported wharf structures subjected to liquefaction-induced lateral ground deformations. Several numerical challenges exist for analysis of this highly nonlinear soil-structure interaction, which require robust, yet practical, solutions that are validated with experimental data. This study presents a numerical model of a pile-supported wharf and evaluates the applicability of a soil constitutive model, and modeling assumptions and methods by using recorded data from a well-instrumented, large-scale centrifuge test. The objectives of this study include: (a) evaluating the performance of a recently developed pressure-dependent multi-yield surface constitutive soil model …
Driver And Bicyclist Comprehension Of Blue Light Detection Confirmation Systems, Douglas P. Cobb, Hisham Jashami, Christopher Monsere, Sirisha Kothuri, David S. Hurwitz
Driver And Bicyclist Comprehension Of Blue Light Detection Confirmation Systems, Douglas P. Cobb, Hisham Jashami, Christopher Monsere, Sirisha Kothuri, David S. Hurwitz
Civil and Environmental Engineering Faculty Publications and Presentations
This study analyzed motorist and bicyclist understanding and preference of positive confirmation of detection of a bicycle by the traffic signal infrastructure using a blue light detection confirmation (BLDC). The research analyzed results of an online survey of 1,123 respondents and intercept survey of 337 respondents. The study initially found that participants of the survey did not understand the meaning of the blue light itself, but comprehension of the system rose from 40% to 50% when supplemental signs were used. Respondents overwhelmingly indicated that they preferred the sign option that included symbols, text, and a representation of the blue light, …
Dissecting Succulence: Crassulacean Acid Metabolism And Hydraulic Capacitance Are Independent Adaptations In Clusia Leaves, Alistair Leverett, Samantha Hartzell, Klaus Winter, Milton Garcia, Multiple Additional Authors
Dissecting Succulence: Crassulacean Acid Metabolism And Hydraulic Capacitance Are Independent Adaptations In Clusia Leaves, Alistair Leverett, Samantha Hartzell, Klaus Winter, Milton Garcia, Multiple Additional Authors
Civil and Environmental Engineering Faculty Publications and Presentations
Succulence is found across the world as an adaptation to water-limited niches. The fleshy organs of succulent plants develop via enlarged photosynthetic chlorenchyma and/or achlorophyllous water storage hydrenchyma cells. The precise mechanism by which anatomical traits contribute to drought tolerance is unclear, as the effect of succulence is multifaceted. Large cells are believed to provide space for nocturnal storage of malic acid fixed by crassulacean acid metabolism (CAM), whilst also buffering water potentials by elevating hydraulic capacitance (CFT). The effect of CAM and elevated CFT on growth and water conservation have not been compared, despite the assumption that these adaptations …
Damage Detection In Reinforced Concrete Member Using Local Time-Frequency Transform Applied To Vibration Measurements, Ning Liu, Thomas Schumacher, Yan Li, Lina Xu, Bo Wang
Damage Detection In Reinforced Concrete Member Using Local Time-Frequency Transform Applied To Vibration Measurements, Ning Liu, Thomas Schumacher, Yan Li, Lina Xu, Bo Wang
Civil and Environmental Engineering Faculty Publications and Presentations
Signal processing and analysis of structural vibration measurements are key components of structural damage detection (SDD) in structural health monitoring (SHM). The goal of signal processing is to extract subtle changes in the measured signals, which can be used to infer changes in structural parameters and damage. Time-frequency analysis is one of the most popular characterization methods for studying non-stationary vibration signals. In this article, the local time-frequency transform (LTFT) is applied and evaluated to calculate the time-domain signals because of its excellent time-frequency energy distribution properties. The LTFT matches the input data by the Fourier basis in an inverse …
Eugenol, Menthol And Other Flavour Chemicals In Kreteks And ‘White’ Cigarettes Purchased In Indonesia, Joanna Cohen, Beladenta Amalia, Wentai Luo, Kevin J. Mcwhirter, James F. Pankow
Eugenol, Menthol And Other Flavour Chemicals In Kreteks And ‘White’ Cigarettes Purchased In Indonesia, Joanna Cohen, Beladenta Amalia, Wentai Luo, Kevin J. Mcwhirter, James F. Pankow
Civil and Environmental Engineering Faculty Publications and Presentations
Background Flavoured tobacco products are not restricted in Indonesia, a country with about 68 million adults who smoke. Most use clove-mixed tobacco cigarettes (‘kreteks’); non-clove (‘white’) cigarettes are also available. Although the use of flavour chemicals has been identified by WHO as promoting tobacco use, little has been reported for Indonesia about the levels of flavourants in either kreteks or ‘white cigarettes’.
Methods 22 kretek brand variants and nine ‘white’ cigarette brand variants were purchased in Indonesia during 2021/2022; one of the kretek packs contained three colour-coded variants, giving a total sample number of 24 for the kreteks. Chemical analyses …
Implementing Super-Resolution Of Non-Stationary Tides With Wavelets: An Introduction To Cwt_Multi, Matthew Lobo, David A. Jay, Silvia Innocenti, Stefan A. Talke, Steven Dykstra, Pascal Matte
Implementing Super-Resolution Of Non-Stationary Tides With Wavelets: An Introduction To Cwt_Multi, Matthew Lobo, David A. Jay, Silvia Innocenti, Stefan A. Talke, Steven Dykstra, Pascal Matte
Civil and Environmental Engineering Faculty Publications and Presentations
Tides are often non-stationary due to non-astronomical influences. Investigating variable tidal properties implies a tradeoff between separating adjacent frequencies (using long analysis windows) and resolving their time variations (short windows). Previous continuous wavelet transform (CWT) tidal methods resolved tidal species. Here, we present CWT_Multi, a Matlab code that: a) uses CWT linearity (via the “Response Coefficient Method”) to implement super-resolution (Munk and Hasselman 1964); b) provides a Munk-Hasselman constituent-selection criterion; and c) introduces an objective, time-variable form of inference (“dynamic inference”) based on time-varying data properties. CWT_Multi resolves tidal species on time-scales of days and multiple constituents per species with …
Exploratory Analysis Of Factors Affecting Home Delivery Returns, Michael Bronson, Miguel Figliozzi, Ali Riahi Samani, Sabya Mishra
Exploratory Analysis Of Factors Affecting Home Delivery Returns, Michael Bronson, Miguel Figliozzi, Ali Riahi Samani, Sabya Mishra
Civil and Environmental Engineering Faculty Publications and Presentations
E-commerce and house deliveries have experienced a rapid growth in the last two decades. The return of online shopping products is an undesirable side effect of online shopping that has not been properly studied in the transportation literature. Utilizing binary logit models, this research answers two novel research questions focusing on the online shopping channel: (i) What household characteristics are associated with a higher or lower propensity to return online purchases? and (ii) What type of products contribute to positive return delivery rates? To answer these questions models are developed using data collected from a household online survey of e-commerce …
Sensor Formed From Conductive Nanoparticles And A Porous Non-Conductive Substrate, Erik T. Thostenson, Thomas Schumacher
Sensor Formed From Conductive Nanoparticles And A Porous Non-Conductive Substrate, Erik T. Thostenson, Thomas Schumacher
Civil and Environmental Engineering Faculty Publications and Presentations
In various aspects, the sensors include a substrate that is porous and non-conductive with nanoparticles deposited onto the substrate within pores of the substrate by an electrophoretic process to form a sensor element. The nanoparticles are electrically conductive. The sensor includes a detector in communication with the sensor element to measure a change in an electrical property of the sensor element. The change in the electrical property may result from alterations in quantum tunneling between nanoparticles within the sensor element, in various aspects.
Cyclic Porewater Pressure Generation In Intact Silty Soils, Arash Khosravifar, Stephen Dickenson, Diane Moug
Cyclic Porewater Pressure Generation In Intact Silty Soils, Arash Khosravifar, Stephen Dickenson, Diane Moug
Civil and Environmental Engineering Faculty Publications and Presentations
The results of cyclic strain-controlled, constant volume direct simple shear (CDSS) tests and field shaking tests have been evaluated for intact, natural, low-plastic silts from six different fine-grained soils with 54%–100% fines content, 47%–83% silt content, and plasticity indices (PI) ranging from nonplastic to 16. These tests constitute a subset of a larger archive of CDSS tests performed on silt deposits from the Pacific Northwest, British Columbia, and Alaska collected and analyzed by the co-authors. The cyclic data are presented in this paper for two objectives: (a) to characterize cyclically-induced excess pore pressure generation in intermediate soils with various soil …
Pile-Supported Wharves Subjected To Inertial Loads And Lateral Ground Deformations. Ii: Guidelines For Equivalent Static Analysis, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough
Pile-Supported Wharves Subjected To Inertial Loads And Lateral Ground Deformations. Ii: Guidelines For Equivalent Static Analysis, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough
Civil and Environmental Engineering Faculty Publications and Presentations
An equivalent static analysis (ESA) procedure is proposed for the design of pile-supported wharves subjected to combined inertial and kinematic loads during earthquakes. The accuracy of the ESA procedure was evaluated against measurements from five large-scale centrifuge tests. The wharf structures in these tests were subjected to a suite of recorded ground motions and the associated superstructure inertia, as well as earthquake-induced slope deformations of varying magnitudes. It is shown that large bending moments at depths greater than 10 pile diameters were primarily induced by kinematic demands and can be estimated by applying soil displacements only (i.e., 100% kinematic). In …
Pile-Supported Wharves Subjected To Inertial Loads And Lateral Ground Deformations. I: Experimental Results From Centrifuge Tests, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough
Pile-Supported Wharves Subjected To Inertial Loads And Lateral Ground Deformations. I: Experimental Results From Centrifuge Tests, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough
Civil and Environmental Engineering Faculty Publications and Presentations
Five dynamic, large-scale centrifuge tests on pile-supported wharves were used to investigate the time- and depth-dependent nature of kinematic and inertial demands on the deep foundations during earthquake loading. The wharf structures in the physical experiments were subjected to a suite of recorded ground motions and imposed superstructure inertial demands on the piles. Partial to full liquefaction in loose sand resulted in slope deformations of varying magnitudes that imposed kinematic demands on the piles. It was found that the wharf inertia and soil displacements were always in phase during the critical cycle when bending moments were at their maximum values. …
Ethyl Maltol, Vanillin, Corylone And Other Conventional Confectionery-Related Flavour Chemicals Dominate In Some E-Cigarette Liquids Labelled ‘Tobacco’ Flavoured, Esther E. Omaiye, Wentai Luo, Kevin J. Mcwhirter, James F. Pankow, Prue Talbot
Ethyl Maltol, Vanillin, Corylone And Other Conventional Confectionery-Related Flavour Chemicals Dominate In Some E-Cigarette Liquids Labelled ‘Tobacco’ Flavoured, Esther E. Omaiye, Wentai Luo, Kevin J. Mcwhirter, James F. Pankow, Prue Talbot
Civil and Environmental Engineering Faculty Publications and Presentations
Background The increased popularity of electronic cigarettes (e-cigarettes) has been linked to the abundance of flavoured products that are attractive to adolescents and young adults. In the last decade, e-cigarette designs have evolved through four generations that include modifications in battery power, e-cigarette liquid (e-liquid) reservoirs and atomiser units. E-liquids have likewise evolved in terms of solvent use/ratios, concentration and number of flavour chemicals, use of nicotine salts and acids, the recent increased use of synthetic cooling agents and the introduction of synthetic nicotine. Our current objective was to evaluate and compare the evolving composition of tobacco-flavoured e-liquids over the …
Warming Of The Willamette River, 1850–Present: The Effects Of Climate Change And Direct Human Interventions, Stefan Talke, David Jay, Heida Diefenderfer
Warming Of The Willamette River, 1850–Present: The Effects Of Climate Change And Direct Human Interventions, Stefan Talke, David Jay, Heida Diefenderfer
Civil and Environmental Engineering Faculty Publications and Presentations
Using archival research methods, we found and combined data from multiple sources to produce a unique, 140 year record of daily water temperature (Tw) in the lower Willamette River, Oregon (1881–1890, 1941–present). Additional daily weather and river flow records from the 1850s onwards are used to develop and validate a statistical regression model of Tw for 1850–2020. The model simulates the time-lagged response of Tw to air temperature and river flow, and is calibrated for three distinct time periods: the late 19th, mid 20th, and early 21st centuries. Results show that Tw has trended upwards at ~1.1 °C …
Disposable Puff Bar Electronic Cigarettes: Chemical Composition And Toxicity Of E-Liquids And A Synthetic Coolant, Esther E. Omaiye, Wentai Luo, Kevin J. Mcwhirter, James F. Pankow, Prue Talbot
Disposable Puff Bar Electronic Cigarettes: Chemical Composition And Toxicity Of E-Liquids And A Synthetic Coolant, Esther E. Omaiye, Wentai Luo, Kevin J. Mcwhirter, James F. Pankow, Prue Talbot
Civil and Environmental Engineering Faculty Publications and Presentations
The popularity of disposable fourth-generation electronic cigarettes (ECs) among young adults and adolescents has been increasing since the ban on flavored cartridge EC products such as JUUL. Although the constituents and toxicity of some cartridge-based fourth-generation ECs, such as JUUL, have been studied, limited data exist for other disposable ECs such as Puff. The purpose of this study was to determine flavor chemicals, synthetic coolants, and nicotine concentrations in 16 disposable Puff devices, evaluate the cytotoxicity of the different flavors from the Puff brand using in vitro assays, and investigate the health risks of synthetic coolants in EC products. Gas …
Measurement Of Enantiomer Percentages For Five Monoterpenes From Six Conifer Species By Cartridge-Tube-Based Passive Sampling Adsorption–Thermal Desorption (Ps-Atd), Ying Wang, Wentai Luo, Todd Rosenstiel, James F. Pankow
Measurement Of Enantiomer Percentages For Five Monoterpenes From Six Conifer Species By Cartridge-Tube-Based Passive Sampling Adsorption–Thermal Desorption (Ps-Atd), Ying Wang, Wentai Luo, Todd Rosenstiel, James F. Pankow
Civil and Environmental Engineering Faculty Publications and Presentations
Many monoterpenes have at least two different stereochemical forms, and many biosynthetic pathways are known to favor one product over the other(s). A rapid method was developed and used in the determination of the (-/+" role="presentation" style="box-sizing: border-box; border-radius: 0px; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">)-enantiomeric distributions for α-pinene, β-pinene, camphene, limonene, and β-phellandrene as emitted by plant material from six conifer species. The six species included the two pine species Pseudotsuga …
Combining Passive And Active Ultrasonic Stress Wave Monitoring Techniques: Opportunities For Condition Evaluation Of Concrete Structures, Thomas Schumacher, Ernst Niederleithinger
Combining Passive And Active Ultrasonic Stress Wave Monitoring Techniques: Opportunities For Condition Evaluation Of Concrete Structures, Thomas Schumacher, Ernst Niederleithinger
Civil and Environmental Engineering Faculty Publications and Presentations
Concrete structures are invaluable assets to a society and managing them efficiently and effectively can be supported by information gathered through structural health monitoring (SHM). In this paper, a combined approach based on passive, i.e., acoustic emission (AE), and active, i.e., ultrasonic stress wave (USW) monitoring techniques for application to concrete structures is proposed and evaluated. While AE and USW are based on the same underlying physics, i.e., wave motion in solids, they differ fundamentally with respect to the nature of the source. For the former, external stimuli such as mechanical loads or temperature cause the rapid release of energy …
A Heuristic For The Two-Echelon Multi-Period Multi-Product Location–Inventory Problem With Partial Facility Closing And Reopening, Puntipa Punyim, Ampol Karoonsoontawong, Avinash Unnikrishnan, Vatanavongs Ratanavaraha
A Heuristic For The Two-Echelon Multi-Period Multi-Product Location–Inventory Problem With Partial Facility Closing And Reopening, Puntipa Punyim, Ampol Karoonsoontawong, Avinash Unnikrishnan, Vatanavongs Ratanavaraha
Civil and Environmental Engineering Faculty Publications and Presentations
In this paper, the two-echelon multi-period multi-product location–inventory problem with partial facility closing and reopening is studied. For each product and period, plants serve warehouses, which serve consolidation hubs, which service customers with independent, normally distributed demands. The schedule of construction, temporary partial closing, and reopening of modular capacities of facilities, the continuous-review inventory control policies at warehouses, the allocation of customer demands to hubs, and the allocation of hubs to warehouses are determined. The service levels for stockout at warehouses during lead time and the violation of warehouse and hub capacities are explicitly considered. The proposed mixed-integer non-linear program …
Assessing The Impact Of Three Intersection Treatments In A Bicycling Simulator, Logan Scott-Deeter, David Hurwitz, Brendan Russo, Edward Smaglik, Sirisha Kothuri
Assessing The Impact Of Three Intersection Treatments In A Bicycling Simulator, Logan Scott-Deeter, David Hurwitz, Brendan Russo, Edward Smaglik, Sirisha Kothuri
Civil and Environmental Engineering Faculty Publications and Presentations
Bicyclist safety at urban intersections is a critical element for encouraging an increase in bicycle commuting. With cyclist injury and fatality rates rising due to collisions with vehicles at signalized intersections, increasing the safety of riders continues to be an important consideration when promoting this mode of transportation. Previous research has addressed crash causality and helped to develop several roadway treatments to improve bicyclist safety, but little has been done to compare and contrast the benefits of the various treatment types. This bicycling simulator study examined the impacts of three different intersection treatments (i.e., bike box, mixing zone, and bicycle …
Experimental Investigation On Short Concrete Columns Laterally Strengthened With Ferrocement And Cfrp, Wisam Amer Aules, Yasir Saeed, Hosam Abdullah Al-Azzawi, Franz Rad
Experimental Investigation On Short Concrete Columns Laterally Strengthened With Ferrocement And Cfrp, Wisam Amer Aules, Yasir Saeed, Hosam Abdullah Al-Azzawi, Franz Rad
Civil and Environmental Engineering Faculty Publications and Presentations
The use of ferrocement in strengthening reinforced concrete (RC) structures has increased recently. Ferrocement has mostly been used to provide extra confinement for RC columns. However, its performance, especially in combination with CFRP confinement has not yet been fully understood. In this study, a total of fifteen columns were experimentally tested to investigate the effects of using ferrocement confinement in strengthening square RC columns. The combination between CFRP and ferrocement in strengthening RC columns has also been investigated. In addition to providing extra confinement, ferrocement is used to modify the shape of square columns to curvilinear shape, which is more …
Systemic Opportunities To Improve Older Pedestrian Safety: Merging Crash Data Analysis And A Stakeholder Workshop, Jason C. Anderson, Sirisha Kothuri, Christopher M. Monsere, David S. Hurwitz
Systemic Opportunities To Improve Older Pedestrian Safety: Merging Crash Data Analysis And A Stakeholder Workshop, Jason C. Anderson, Sirisha Kothuri, Christopher M. Monsere, David S. Hurwitz
Civil and Environmental Engineering Faculty Publications and Presentations
This paper presents a framework for improving older pedestrian safety in regard to serious (fatal and incapacitating) crashes, using Oregon as a case study. On review of state and federal practices pertaining to older pedestrian safety, 4 years of crash data identified 112 older (≥ 65 years) pedestrian serious injury crashes. These data were explored for factors that might be addressed systemically using two methods. First, raw frequencies in the crash data were assessed to determine trends and crash-related factors that are overrepresented. Second, a random forest analysis was conducted to determine important variables for predicting older pedestrian serious injury …
A Hybrid Approach To Improve Flood Forecasting By Combining A Hydrodynamic Flow Model And Artificial Neural Networks, Li Li, Kyong Soo Jun
A Hybrid Approach To Improve Flood Forecasting By Combining A Hydrodynamic Flow Model And Artificial Neural Networks, Li Li, Kyong Soo Jun
Civil and Environmental Engineering Faculty Publications and Presentations
Climate change is driving worsening flood events worldwide. In this study, a hybrid approach based on a combination of the optimization of a hydrodynamic model and an error correction modeling that exploit different aspects of the physical system is proposed to improve the forecasting accuracy of flood water levels. In the parameter optimization procedure for the hydrodynamic model, Manning’s roughness coefficients were estimated by considering their spatial distribution and temporal variation in unsteady flow conditions. In the following error correction procedure, the systematic errors of the optimized hydrodynamic model were captured by combining the input variable selection method using partial …
Robust Multi-Period Maximum Coverage Drone Facility Location Problem Considering Coverage Reliability, Darshan Rajesh Chauhan, Avinash Unnikrishnan, Miguel A. Figliozzi, Stephen D. Boyles
Robust Multi-Period Maximum Coverage Drone Facility Location Problem Considering Coverage Reliability, Darshan Rajesh Chauhan, Avinash Unnikrishnan, Miguel A. Figliozzi, Stephen D. Boyles
Civil and Environmental Engineering Faculty Publications and Presentations
This study proposes a multi-period facility location formulation to maximize coverage while meeting a coverage reliability constraint. The coverage reliability constraint is a chance constraint limiting the probability of failure to maintain the desired service standard, commonly followed by emergency medical services and fire departments. Further, uncertainties in the failure probabilities are incorporated by utilizing robust optimization using polyhedral uncertainty sets, which results in a compact mixed-integer linear program. A case study in the Portland, OR metropolitan area is analyzed for employing unmanned aerial vehicles (UAVs) or drones to deliver defibrillators in the region to combat out-of-hospital cardiac arrests. In …
Modeling Cyanobacteria Vertical Migration, Corina Christina Mae Overman, Scott A. Wells
Modeling Cyanobacteria Vertical Migration, Corina Christina Mae Overman, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Cyanobacteria often cause harmful algal blooms and release toxic substances that can harm humans and animals. Accurately modeling these phytoplankton is a step towards predicting, preventing, and controlling such blooms. Certain cyanobacteria species are known to migrate vertically in the water column on a daily cycle. Capturing this behavior is one aspect of modeling their dynamics. Previous studies on modeling cyanobacterial vertical migration are reviewed and summarized. Several models of cyanobacteria vertical movement are tested using data from field studies. These models are applied using both continuum and particle-tracking frameworks. Models range in complexity from simple functions of time to …
Effects Of Long Duration Earthquakes On The Interaction Of Inertial And Liquefaction-Induced Kinematic Demands On Pile-Supported Wharves, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Nason Mccullough, Scott Schlechter
Effects Of Long Duration Earthquakes On The Interaction Of Inertial And Liquefaction-Induced Kinematic Demands On Pile-Supported Wharves, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Nason Mccullough, Scott Schlechter
Civil and Environmental Engineering Faculty Publications and Presentations
Nonlinear dynamic analyses were performed to evaluate the effects of ground motion duration on the dynamic response of a pile-supported wharf subjected to liquefaction-induced lateral ground deformations. The numerical model was first calibrated using recorded data from a well-instrumented centrifuge test, after which incremental dynamic analyses were conducted using a suite of spectrally matched motions with different durations. The nonlinear dynamic analyses were performed to evaluated three loading scenarios: combined effects of inertial loads from the wharf deck and kinematic loads from ground deformations, deck inertial loads only in the absence of liquefaction (with minimal kinematic loads), and kinematic loads …
A Self-Referencing Non-Destructive Test Method To Detect Damage In Reinforced Concrete Bridge Decks Using Nonlinear Vibration Response Characteristics, Ali Hafiz, Thomas Schumacher, Anis M. Raad
A Self-Referencing Non-Destructive Test Method To Detect Damage In Reinforced Concrete Bridge Decks Using Nonlinear Vibration Response Characteristics, Ali Hafiz, Thomas Schumacher, Anis M. Raad
Civil and Environmental Engineering Faculty Publications and Presentations
Several non-destructive test (NDT) methods, namely visual inspection, hammer sounding, chain drag, impulse response testing, impact echo testing, ultrasonic (array) echo testing, and under certain conditions ground penetrating radar (GPR) are currently used to detect and estimate the extent of damage such as delaminations in reinforced concrete bridge decks. In this article, we present a self-referencing NDT method that builds on impulse response (IR) testing to detect damage using nonlinear vibration characteristics. The hypothesis is that for an undamaged deck, varying the impact force applied to a specific test point does not affect the corresponding frequency response function (FRF) for …