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Articles 1 - 30 of 105
Full-Text Articles in Engineering
Measuring Volatile Emissions From Moss Gametophytes: A Review Of Methodologies And New Applications, Danlyn L. Brennan, Leslie M. Kollar, Scott Kiel, Timea Deakova, Aurélie Laguerre, Stuart F. Mcdaniel, Sarah Eppley, Elliott T. Gall, Todd Rosenstiel
Measuring Volatile Emissions From Moss Gametophytes: A Review Of Methodologies And New Applications, Danlyn L. Brennan, Leslie M. Kollar, Scott Kiel, Timea Deakova, Aurélie Laguerre, Stuart F. Mcdaniel, Sarah Eppley, Elliott T. Gall, Todd Rosenstiel
Center for Life in Extreme Environments Publications
Mosses inhabit nearly all terrestrial ecosystems and engage in important interactions with nitrogen-fixing microbes, sperm-dispersing arthropods, and other plants. It is hypothesized that these interactions could be mediated by biogenic volatile organic compounds (BVOCs). Moss BVOCs may play fundamental roles in influencing local ecologies, such as biosphere–atmosphere–hydrosphere communications, physiological and evolutionary dynamics, plant–microbe interactions, and gametophyte stress physiology. Further progress in quantifying the composition, magnitude, and variability of moss BVOC emissions, and their response to environmental drivers and metabolic requirements, is limited by methodological and analytical challenges. We review several sampling techniques with various analytical approaches and describe best practices …
Maximum Profit Facility Location And Dynamic Resource Allocation For Instant Delivery Logistics, Darshan Chauhan, Avinash Unnikrishnan, Stephen D. Boyles
Maximum Profit Facility Location And Dynamic Resource Allocation For Instant Delivery Logistics, Darshan Chauhan, Avinash Unnikrishnan, Stephen D. Boyles
Civil and Environmental Engineering Faculty Publications and Presentations
Increasing e-commerce activity, competition for shorter delivery times, and innovations in transportation technologies have pushed the industry toward instant delivery logistics. This paper studies a facility location and online demand allocation problem applicable to a logistics company expanding to offer instant delivery service using unmanned aerial vehicles or drones. The problem is decomposed into two stages. During the planning stage, the facilities are located, and product and battery capacity are allocated. During the operational stage, customers place orders dynamically and real-time demand allocation decisions are made. The paper explores a multi-armed bandit framework for maximizing the cumulative reward realized by …
Exploring How Antecedent Precipitation Amount And The Effects Of Covid-19 Affect Stormwater Runoff Quality Along Urban Gradients, Daniel Ramirez, Katherine Gelsey
Exploring How Antecedent Precipitation Amount And The Effects Of Covid-19 Affect Stormwater Runoff Quality Along Urban Gradients, Daniel Ramirez, Katherine Gelsey
REU Final Reports
Stormwater runoff quality is affected by a multitude of factors including surrounding land characteristics, human activities, and antecedent precipitation amounts. We explore how seasonal and variable precipitation affect E. Coli, total suspended solids, nitrogen-nitrate, orthophosphate, lead, and zinc concentrations in Portland, OR, USA. Correlation analysis was conducted between the pollutant concentrations and antecedent rainfall each sample site received for the previous 1, 3, 5, 7, and 30 days from when the sample was taken. We ran Mann-Whitney tests to determine if the levels of the pollutants were statistically different between the wet season and the dry season. We found that …
The Influence Of Channel Deepening On Tides, River Discharge Effects, And Storm Surge, Stefan A. Talke, Ramin Familkhalili, David A. Jay
The Influence Of Channel Deepening On Tides, River Discharge Effects, And Storm Surge, Stefan A. Talke, Ramin Familkhalili, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
We combine archival research, semi-analytical models, and numerical simulations to address the following question: how do changes to channel geometry alter tidal properties and flood dynamics in a hyposynchronous, strongly frictional estuary with a landward decay in tidal amplitudes? Records in the Saint Johns River Estuary since the 1890s show that tidal range has doubled in Jacksonville, Florida. Near the estuary inlet, tidal discharge approximately doubled but tidal amplitudes increased only ~6%. Modeling shows that increased shipping channel depths from 5-6 to ~13m drove the observed changes, with other factors like channel shortening and width reduction producing comparatively minor effects. …
Modeling The Effectiveness Of Cooling Trenches For Stormwater Temperature Mitigation, Scott A. Wells
Modeling The Effectiveness Of Cooling Trenches For Stormwater Temperature Mitigation, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Due to elevated runoff stormwater temperatures from impervious areas, one management strategy to reduce stormwater temperature is the use of underground flow through rock media termed a cooling trench. This paper examines the governing equations for the liquid phase and media phases for modeling the temperature leaving a cooling trench assuming that changes in temperature occurred longitudinally through the cooling trench. This model is dependent on parameters such as the media type, porosity, media initial temperature, inflow rate, and inflow temperature. Several approaches were explored mathematically for evaluating the change in temperature of the water and the cooling trench media. …
Implementation Of A Novel Inertial Mass System And Comparison To Existing Mass-Rig Systems For Shake Table Experiments, Alvaro Lopez, Peter Dusicka
Implementation Of A Novel Inertial Mass System And Comparison To Existing Mass-Rig Systems For Shake Table Experiments, Alvaro Lopez, Peter Dusicka
Civil and Environmental Engineering Faculty Publications and Presentations
Shake table testing is one of the more effective experimental approaches used to study and evaluate seismic performance of structures. Reduced-scale models can still result in large-scale specimens where incorporating the required inertial mass effectively and safely can be challenging. This study proposes a new system of arranging the mass in the experiments that combines the realism of mass participation during earthquake excitation when supported by the shake table with laboratory practicality considerations of the mass positioned off the specimen. The characteristics and dynamic motion equations for the proposed system are described and applied to shake table experiments involving large-scale …
High-Temperature Performance Of Ambient-Cured Alkali- Activated Binder Concrete, Kruthi Kiran Ramagiri, Darshan Chauhan, Shashank Gupta, Arkamitra Kar, Dibyendu Adak, Abhijit Mukherjee
High-Temperature Performance Of Ambient-Cured Alkali- Activated Binder Concrete, Kruthi Kiran Ramagiri, Darshan Chauhan, Shashank Gupta, Arkamitra Kar, Dibyendu Adak, Abhijit Mukherjee
Civil and Environmental Engineering Faculty Publications and Presentations
Owing to their lower carbon footprint and efficient performance compared to portland cement (PC), alkali-activated binders (AAB) show promising potential as an alternative to PC. The present paper investigates the high-temperature performance of AAB concrete through compressive and bond strength tests. Four different AAB concrete mixes with varying proportions of fly ash: slag (100:0, 70:30, 60:40, and 50:50) cured under ambient conditions are exposed to elevated temperatures. The mechanical performance of AAB concrete is corroborated with microstructural changes. The results show that AAB concrete with fly ash: slag ratio of 70:30 exhibits the best mechanical performance after exposure to elevated …
Sea Level, Tidal, And River Flow Trends In The Lower Columbia River Estuary, 1853-Present, Stefan Talke, Andrew Mahedy, David A. Jay, Patrick Lau, Conrad Hilley, Amanda Hudson
Sea Level, Tidal, And River Flow Trends In The Lower Columbia River Estuary, 1853-Present, Stefan Talke, Andrew Mahedy, David A. Jay, Patrick Lau, Conrad Hilley, Amanda Hudson
Civil and Environmental Engineering Faculty Publications and Presentations
Few tidal records are available pre-1900 for the Pacific Ocean. We improve data coverage by recovering historical tabulations and digitizing analog tide rolls from Astoria, Oregon for 1853-1876. Nearly 13,500 overlapping images of tides from 1855-1870 were digitized at a 6 minute resolution using a line-finding algorithm. Available hourly and high/low tabulations were also digitized, as were nearby hourly records from 1933-1943. Uncertainty was assessed by evaluating manual staff measurements, historical documents, and leveling surveys. Results suggest that uncertainty in mean sea level varies from ± 0.07m (early 1850s) to ± 0.03m (1867-1876) and is driven primarily by datum and …
Nineteenth-Century Tides In The Gulf Of Maine And Implications For Secular Trends, Richard D. Ray, Stefan A. Talke
Nineteenth-Century Tides In The Gulf Of Maine And Implications For Secular Trends, Richard D. Ray, Stefan A. Talke
Civil and Environmental Engineering Faculty Publications and Presentations
Since the early twentieth century, the amplitudes of tidal constituents in the Gulf of Maine and Bay of Fundy display clear secular trends that are among the largest anywhere observed for a regional body of water. The M2 amplitude at Eastport, Maine, increased at a rate of 14.1 ± 1.2 cm per century until it temporarily dropped during 1980–1990, apparently in response to changes in the wider North Atlantic. Annual tidal analyses indicate M2 reached an all‐time high amplitude last year (2018). Here we report new estimates of tides derived from nineteenth century water‐level measurements found in the U.S. National …
Historical Changes In Lower Columbia River And Estuary Floods: A Numerical Study, Lumas Helaire, Stefan Talke, David A. Jay, Andrew Mahedy
Historical Changes In Lower Columbia River And Estuary Floods: A Numerical Study, Lumas Helaire, Stefan Talke, David A. Jay, Andrew Mahedy
Civil and Environmental Engineering Faculty Publications and Presentations
Over the past 150 years, the Lower Columbia River Estuary controlling depth has approximately doubled, the majority of historical wetlands and floodplain have been reclaimed, numerous infrastructure projects have altered and confined flow pathways, and significant natural and anthropogenic changes to the discharge hydrograph have occurred. To investigate the effect of these changes on tides, river slope, and flood water levels, we construct and validate numerical models that simulate flow over late nineteenth‐century and present‐day bathymetry. The models are validated using archival (1853–1877) and modern tide measurements throughout the Lower Columbia River Estuary and river stage measurements from the tidal …
Analysis And Application Of Log-Linear And Quantile Regression Models To Predict Bus Dwell Times, Travis B. Glick, Miguel Figliozzi
Analysis And Application Of Log-Linear And Quantile Regression Models To Predict Bus Dwell Times, Travis B. Glick, Miguel Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
Understanding the key factors that contribute to transit travel times and travel time variability is an essential part of transit planning and research. Delay that occurs when buses service bus stops, dwell time, is one of the main sources of travel time variability and has therefore been the subject of ongoing research to identify and quantify its determinants. Previous research has focused on testing new variables using linear regressions that may be added to models to improve predictions. An important assumption of linear regression models used in past research efforts is homoscedasticity or the equal distribution of the residuals across …
Production Of Secondary Organic Aerosol During Aging Of Biomass Burning Smoke From Fresh Fuels And Its Relationship To Voc Precursors, A. T. Ahern, E. S. Robinson, D. S. Tkacik, L. E. Hatch, Kelley Barsanti, C. E. Stockwell, Robert J. Yokelson, Multiple Additional Authors
Production Of Secondary Organic Aerosol During Aging Of Biomass Burning Smoke From Fresh Fuels And Its Relationship To Voc Precursors, A. T. Ahern, E. S. Robinson, D. S. Tkacik, L. E. Hatch, Kelley Barsanti, C. E. Stockwell, Robert J. Yokelson, Multiple Additional Authors
Civil and Environmental Engineering Faculty Publications and Presentations
After smoke from burning biomass is emitted into the atmosphere, chemical and physical processes change the composition and amount of organic aerosol present in the aged, diluted plume. During the fourth Fire Lab at Missoula Experiment, we performed smog‐chamber experiments to investigate formation of secondary organic aerosol (SOA) and multiphase oxidation of primary organic aerosol (POA). We simulated atmospheric aging of diluted smoke from a variety of biomass fuels while measuring particle composition using high‐resolution aerosol mass spectrometry. We quantified SOA formation using a tracer ion for low‐volatility POA as a reference standard (akin to a naturally occurring internal standard). …
The Quest For Model Uncertainty Quantification: A Hybrid Ensemble And Variational Data Assimilation Framework, Peyman Abbaszadeh, Hamid Moradkhani, Dacian Daescu
The Quest For Model Uncertainty Quantification: A Hybrid Ensemble And Variational Data Assimilation Framework, Peyman Abbaszadeh, Hamid Moradkhani, Dacian Daescu
Civil and Environmental Engineering Faculty Publications and Presentations
This article presents a novel approach to couple a deterministic four‐dimensional variational (4DVAR) assimilation method with the particle filter (PF) ensemble data assimilation system, to produce a robust approach for dual‐state‐parameter estimation. In our proposed method, the Hybrid Ensemble and Variational Data Assimilation framework for Environmental systems (HEAVEN), we characterize the model structural uncertainty in addition to model parameter and input uncertainties. The sequential PF is formulated within the 4DVAR system to design a computationally efficient feedback mechanism throughout the assimilation period. In this framework, the 4DVAR optimization produces the maximum a posteriori estimate of state variables at the beginning …
Bigger Tides, Less Flooding: Effects Of Dredging On Barotropic Dynamics In A Highly Modified Estuary, David K. Ralston, Stefan Talke, W. Rockwell Geyer, Hussein A. M. Al-Zubaidi, Christopher K. Sommerfield
Bigger Tides, Less Flooding: Effects Of Dredging On Barotropic Dynamics In A Highly Modified Estuary, David K. Ralston, Stefan Talke, W. Rockwell Geyer, Hussein A. M. Al-Zubaidi, Christopher K. Sommerfield
Civil and Environmental Engineering Faculty Publications and Presentations
Since the late nineteenth century, channel depths have more than doubled in parts of New York Harbor and the tidal Hudson River, wetlands have been reclaimed and navigational channels widened, and river flow has been regulated. To quantify the effects of these modifications, observations and numerical simulations using historical and modern bathymetry are used to analyze changes in the barotropic dynamics. Model results and water level records for Albany (1868 to present) and New York Harbor (1844 to present) recovered from archives show that the tidal amplitude has more than doubled near the head of tides, whereas increases in the …
Comparative Analysis Of Mosquito Trap Counts In The Peruvian Amazon: Effect Of Trap Type And Other Covariates On Counts And Diversity, George W. Peck, Fanny Castro-Llanos, Victor Lopez-Sifuentes, Erica Lindroth
Comparative Analysis Of Mosquito Trap Counts In The Peruvian Amazon: Effect Of Trap Type And Other Covariates On Counts And Diversity, George W. Peck, Fanny Castro-Llanos, Victor Lopez-Sifuentes, Erica Lindroth
Civil and Environmental Engineering Faculty Publications and Presentations
Efficient detection of multiple species of adult mosquitoes in various habitats using effective traps is a crucial 1st step in any disease prevention program. Novel trap types that target tropical vectors of human diseases require field testing in the habitat of the vector–disease system in question. This paper analyzes a series of mosquito trapping studies conducted at Mapacocha, San Juan Bautista District, Loreto, Peru, during August–September 2013 and April–May 2014. Six trap configurations were evaluated in forest and rural locations. Adult mosquito counts were analyzed using full Bayesian inference of multilevel generalized linear models and posterior probability point estimates of …
Twelve Questions For The Participatory Modeling Community, Rebecca Jordan, Steven Gray, Moira Zellner, Pierre D. Glynn, Alexey Voinov, Beatrice Hedelin, Eleanor J. Sterling, Kirsten Leong, Laura Schmitt Olabisi, Klaus Hubacek, Pierre Bommel, Todd K. Bendor, Antoine J. Jetter, Bethany Laursen, Alison Singer, Philippe J. Giabbanelli, Nagesh Kolagani, Laura Basco Carrera, Karen Jenni, Christina Prell, National Socio-Environmental Synthesis Center Participatory Modeling Pursuit Working Group
Twelve Questions For The Participatory Modeling Community, Rebecca Jordan, Steven Gray, Moira Zellner, Pierre D. Glynn, Alexey Voinov, Beatrice Hedelin, Eleanor J. Sterling, Kirsten Leong, Laura Schmitt Olabisi, Klaus Hubacek, Pierre Bommel, Todd K. Bendor, Antoine J. Jetter, Bethany Laursen, Alison Singer, Philippe J. Giabbanelli, Nagesh Kolagani, Laura Basco Carrera, Karen Jenni, Christina Prell, National Socio-Environmental Synthesis Center Participatory Modeling Pursuit Working Group
Engineering and Technology Management Faculty Publications and Presentations
Participatory modeling engages the implicit and explicit knowledge of stakeholders to create formalized and shared representations of reality and has evolved into a field of study as well as a practice. Participatory modeling researchers and practitioners who focus specifically on environmental resources met at the National Socio-Environmental Synthesis Center (SESYNC) in Annapolis, Maryland, over the course of 2 years to discuss the state of the field and future directions for participatory modeling. What follows is a description of 12 overarching groups of questions that could guide future inquiry.
A 3d Model For Earthquake-Induced Liquefaction Triggering And Post-Liquefaction Response, Arash Khosravifar, Ahmed Elgamal, Jinchi Lu, John Li
A 3d Model For Earthquake-Induced Liquefaction Triggering And Post-Liquefaction Response, Arash Khosravifar, Ahmed Elgamal, Jinchi Lu, John Li
Civil and Environmental Engineering Faculty Publications and Presentations
A constitutive soil model that was originally developed to model liquefaction and cyclic mobility has been updated to comply with the established guidelines on the dependence of liquefaction triggering to the number of loading cycles, effective overburden stress (Kσ), and static shear stress (Kα). The model has been improved with new flow rules to better capture contraction and dilation in sands and has been implemented as PDMY03 in different computational platforms such as OpenSees finite-element, and FLAC and FLAC3D finite-difference frameworks. This paper presents the new modified framework of analysis and describes a guideline to calibrate the input parameters of …
Baroclinic Tidal Sea Level From Exact-Repeat Mission Altimetry, Edward Zaron
Baroclinic Tidal Sea Level From Exact-Repeat Mission Altimetry, Edward Zaron
Portland Institute for Computational Science Publications
A near-global model for the sea-surface expression of the baroclinic tide has been developed using exact-repeat mission altimetry. The methodology used differs in detail from other altimetry-based estimates of the open ocean baroclinic tide, but it leads to estimates which are broadly similar to previous results. It may be used for prediction of the baroclinic sea level anomaly at the frequencies of the main diurnal and semidiurnal tides, K1, O1, M2, S2, as well as the annual modulates of M2, denoted MA2 and MB2. Based on a …
Relative Sea Level, Tides, And Extreme Water Levels In Boston Harbor From 1825 To 2018, Stefan Talke, A. C. Kemp, J. Woodruff
Relative Sea Level, Tides, And Extreme Water Levels In Boston Harbor From 1825 To 2018, Stefan Talke, A. C. Kemp, J. Woodruff
Civil and Environmental Engineering Faculty Publications and Presentations
Using newly-discovered archival measurements, we construct an instrumental record of water levels and storm tides in Boston (MA) since 1825. After ascertaining the 19th century datum and correcting for a 0–0.03 m bias in the modern tide-gauge record, we show that local, decadally-averaged relative sea level (RSL) rose by 0.2860.05 m since 1826, with an acceleration of 0.02360.009 mm/yr2. Tide range decreased by 5.5% between 1830 and 1910, due in large part to dredging and filling of Boston Harbor, and trended slightly upward thereafter. An evaluation of storm events since 1825 suggests that trends in flood risk are driven by …
Decision Support System For The Design And Planning Of Low-Impact Development Practices: The Case Of Seoul, Jae-Yeol Song, Eun-Sung Chung, Soo Hyun Kim
Decision Support System For The Design And Planning Of Low-Impact Development Practices: The Case Of Seoul, Jae-Yeol Song, Eun-Sung Chung, Soo Hyun Kim
Civil and Environmental Engineering Faculty Publications and Presentations
This study presented the conceptual framework of the water-management analysis module (WMAM) to derive effective physical specifications for the design and planning of low-impact development (LID) practices using the storm-water management model (SWMM). This decision-support system can be used for six LID types and has the following key capabilities: determining relevant LID design parameters within the SWMM that critically influence the hydrological cycle components using a simple sensitivity analysis and determining the best hydrological values for LID planning specification. This study analyzed a highly urbanized university campus as a case study to determine the design and planning specifications for an …
Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena
Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena
REU Final Reports
The Intergovernmental Panel on Climate Change (IPCC) has various Global Climate Models (GCM). One of them, models three greenhouse gases. The increasing amount of greenhouse gases are just a fraction of factors that fuel global climate change. According to the IPCC 2014, climate related extremes such as heatwaves are likely to occur more regularly and are likely to increase in duration. Since 1979, there has been over 9000 deaths that occurred from heat-related incidents in the United States (U.S. Environmental Protection Agency, 2016). Which brings attention to population groups who are exposed to hot temperatures on a frequent basis due …
Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle
Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle
REU Final Reports
Although it is generally understood that urban development can impact the quality of urban streams, there are many factors that affect the concentrations of pollutants being transferred from the built environment to a given output. This study examines the impact of land use surrounding urban streams, specifically, the degree of development and presence or absence of green infrastructure (GI) in these areas on heavy metal (HM) concentrations in Portland, Oregon. After collecting 1021 water quality samples from 2010-2018, we examined the difference in concentrations of HM pollutants across different combinations of land use and season. Increased levels of calcium, magnesium, …
The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed
The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed
REU Final Reports
Plastic particles contaminating the world’s oceans and accumulating in oceanic gyres has become a ubiquitous problem and the solution involving how to clean up the debris efficiently has still not been found. One particular issue is understanding where the greatest densities of debris may be. It is known that floating trash will tend to accumulate in large circular systems of ocean water called gyres, however these areas span thousands of miles of ocean. The present study aims to understand the transport of anisotropic particles in conditions similar to an oceanic environment using experimental methods in an effort to better predict …
Hydro-Climatological Summer Trends In The Continental United States, Naya Mairena Flores
Hydro-Climatological Summer Trends In The Continental United States, Naya Mairena Flores
REU Final Reports
We investigated trends in air temperature, stream temperature and discharge for rivers across the continental United States from the summer months of 1996 to 2016. Using GAGES II from USGS and PRISM and programming language R we analyzed specific hydrological trends in Mann-Kendall’s tests. After collecting the slope values whether they were negative or positive and the P-Values, the significance of that slope, we mapped slopes of trends in GIS. Stream temperature increased 12% of stations across the summer, while air temperature increased 22% of stations, and discharge decreased 15% of stations, respectively. Seven day moving average of daily maximum …
Water Quality Factor Prediction Using Supervised Machine Learning, Kathleen Joslyn
Water Quality Factor Prediction Using Supervised Machine Learning, Kathleen Joslyn
REU Final Reports
The objective of this research is to explore prediction accuracy of water quality factors, with techniques and algorithms in machine learning consisting of a variation of support vector machines - Support Vector Regression (SVR) and the gradient boosting algorithm Extreme Gradient Boosting (XGBoost). Both the XGBoost and SVR algorithms were used to predict nine different factors with success rates ranging from 79% to 99%. Parameters of these algorithms were also explored to test the prediction accuracy levels of individual water quality factors. These parameters included normalizing the data, filling missing data points, and training and testing on a large set …
Inertial And Liquefaction-Induced Kinematic Demands On A Pile-Supported Wharf: Physical Modeling, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough
Inertial And Liquefaction-Induced Kinematic Demands On A Pile-Supported Wharf: Physical Modeling, Milad Souri, Arash Khosravifar, Stephen E. Dickenson, Scott Schlechter, Nason Mccullough
Civil and Environmental Engineering Faculty Publications and Presentations
Results of a centrifuge test on a pile-supported wharf were used to investigate the time-, depth-, and row-dependent nature of kinematic and inertial loading on wharf piles in sloping rockfill. P-y models were calibrated against recorded bending moments in different piles and different depths. It was found that full kinematic demands and full superstructure inertia should be combined to estimate bending moments at pile head and shallow depths (less than 10 diameters below the ground surface). On the contrary, it was found that applying full kinematic demands alone was adequate to estimate pile bending moments at large depths (greater than …
The Effects Of Long-Duration Subduction Earthquakes On Inelastic Behavior Of Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Jonathan Nasr, Arash Khosravifar
The Effects Of Long-Duration Subduction Earthquakes On Inelastic Behavior Of Bridge Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Jonathan Nasr, Arash Khosravifar
Civil and Environmental Engineering Faculty Publications and Presentations
Effective-stress nonlinear dynamic analyses (NDA) were performed for a large-diameter reinforced concrete (RC) pile in multi-layered liquefiable sloped ground. The objective was to assess the effects of earthquake duration on the combination of inertia and liquefaction-induced lateral spreading. A parametric study was performed using input motions from subduction and crustal earthquakes covering a wide range of motion durations. The NDA results showed that the pile head displacements increased under liquefied conditions, compared to nonliquefied conditions, due to liquefaction-induced lateral spreading. The NDA results were used to develop a displacement-based equivalent static analysis (ESA) method that combines inertial and lateral spreading …
Drones For Commercial Last-Mile Deliveries: A Discussion Of Logistical, Environmental, And Economic Trade-Offs, Miguel Figliozzi
Drones For Commercial Last-Mile Deliveries: A Discussion Of Logistical, Environmental, And Economic Trade-Offs, Miguel Figliozzi
Civil and Environmental Engineering Faculty Publications and Presentations
There are no studies that model the potential effectiveness of Unmanned Aerial Vehicles (UAVs) or drones to reduce CO2e lifecycle (including both utilization and vehicle phase) emissions when compared to conventional diesel vans, electric trucks, electric vans, and tricycles. This study presents a novel analysis of lifecycle UAV and ground commercial vehicles CO2e emissions.
Remote Measurements Of Tides And River Slope Using An Airborne Lidar Instrument, Austin S. Hudson, Stefan A. Talke, Ruth Branch, Chris Chickadel, Gordon Farquharson, Andrew Jessup
Remote Measurements Of Tides And River Slope Using An Airborne Lidar Instrument, Austin S. Hudson, Stefan A. Talke, Ruth Branch, Chris Chickadel, Gordon Farquharson, Andrew Jessup
Civil and Environmental Engineering Faculty Publications and Presentations
Tides and river slope are fundamental characteristics of estuaries, but they are usually undersampled due to deficiencies in the spatial coverage of water level measurements. This study aims to address this issue by investigating the use of airborne lidar measurements to study tidal statistics and river slope in the Columbia River estuary. Eight plane transects over a 12-h period yield at least eight independent measurements of water level at 2.5-km increments over a 65-km stretch of the estuary. These data are fit to a sinusoidal curve and the results are compared to seven in situ gauges. In situ– and lidar-based …
Coupling Of Sea Level And Tidal Range Changes, With Implications For Future Water Levels, Adam T. Devlin, David A. Jay, Stefan Talke, Edward D. Zaron, Jiayi Pan, Hui Lin
Coupling Of Sea Level And Tidal Range Changes, With Implications For Future Water Levels, Adam T. Devlin, David A. Jay, Stefan Talke, Edward D. Zaron, Jiayi Pan, Hui Lin
Civil and Environmental Engineering Faculty Publications and Presentations
Are perturbations to ocean tides correlated with changing sea-level and climate, and how will this affect high water levels? Here, we survey 152 tide gauges in the Pacific Ocean and South China Sea and statistically evaluate how the sum of the four largest tidal constituents, a proxy for the highest astronomical tide (HAT), changes over seasonal and interannual time scales. We find that the variability in HAT is significantly correlated with sea-level variability; approximately 35% of stations exhibit a greater than ±50 mm tidal change per meter sea-level fluctuation. Focusing on a subset of three stations with long records, probability …