Engineering Commons^™

Defining Boat Wake Impacts On Shoreline Stability Toward Management And Policy Solutions, Donna Marie Bilkovic, Molly M. Mitchell, Jennifer Davis, Julie Herman, Elizabeth Andrews, Angela King, Pamela Mason, Navid Tahvildari, Jana Davis, Rachel L. Dixon

Civil & Environmental Engineering Faculty Publications

Coastal economies are often supported by activities that rely on commercial or recreational vessels to move people or goods, such as shipping, transportation, cruising, and fishing. Unintentionally, frequent or intense vessel traffic can contribute to erosion of coastlines; this can be particularly evident in sheltered systems where shoreline erosion should be minimal in the absence of boat waves. We reviewed the state of the science of known effects of boat waves on shoreline stability, examined data on erosion, turbidity, and shoreline armoring patterns for evidence of a response to boat waves in Chesapeake Bay, and reviewed existing management and policy …

Odu Researchers' Flood Adaptation Study Honored At International Conference, News @ Odu

News Items

No abstract provided.

Organizational Criteria To Assess Adaptive Capacity In Complex Systems, Abdulrahman Alfaqiri

October 11, 2019: Measuring and Evaluating Resilience

No abstract provided.

Catalytic Transfer Hydrogenation Reactions Of Lipids, Alexander Asiedu

Civil & Environmental Engineering Theses & Dissertations

Catalytic transfer hydrogenation (CTH) of lipids was investigated using 2-propanol as hydrogen donor for producing liquid hydrocarbons, e.g. jet fuels. The main sources of lipids selected in this study were waste cooking oil (WCO) and oil-laden algae-derived biofuel intermediate (BI). Two different catalysts were employed in this study, namely activated carbon and trimetallic-doped zeolite.

The CTH reaction was between WCO and 2-propanol in a continuous flow reactor over a packed-bed activated carbon at near atmospheric pressure. Results revealed a high level of alkenes and aromatics compounds, which are not stable and are not environmentally unfriendly. To reduce these compounds in …

Parallel Jacobi Transformation Algorithm For Generalized Eigen-Solution With Improved Damage Detection Of Truss/Bridge-Type Structures, Maryam Ehsaei

Civil & Environmental Engineering Theses & Dissertations

Serial Jacobi transformation algorithm for the solution of “standard eigen-problems” is re-visited to facilitate the explanation of the proposed parallel transformation algorithm, for which computational efficiency can be realized in this study through “pattern recognition” for the development and explanation of “explicit formulas” to avoid costly matrix time matrix operations. The proposed parallel Jacobi transformation for the solution of “generalized eigen-problems” has also been incorporated into the “improved damage detection” algorithm.

Computational efficiency and robust behaviors for the entire proposed procedures (eigen-solution, damage detection and damage quantification) can be validated through several academic and real-life numerical examples. Numerical results obtained …

Spatiotemporal Downscaling Rainfall Predictions Of North American Regional Climate Change Assessment Program For Entire Virginia, Zhaoyi Cai

Civil & Environmental Engineering Theses & Dissertations

This thesis developed a statistical downscaling approach, which consists of a series of linear regression equations, to spatiotemporally downscale the rainfall predictions from North American Regional Climate Change Assessment Program (NARCCAP) in accordance with the 15-min observed rainfall data at the rain gauges across the state of Virginia. NARCCAP has generated twelve different region-global climate models (RCM-GCMs) with a temporal resolution of 3 hr and a spatial resolution of 50 km over the entire America. Although it has been downscaled already, such resolutions are still too coarse to represent the rain gauges. This means that the RCM-GCMs’ predictions need to …

Application Of A Biodegradable And Recyclable Chelating Agent For Ash Removal From Algae, Temitope George Daramola

Civil & Environmental Engineering Theses & Dissertations

Ash is inherent in algae biomass and it causes operational difficulties, equipment failure, and disposal issues during biomass conversion to biofuels and bioproducts. The objectives of this study are to (i) investigate the use of the biodegradable chelating agent for reducing ash content of algae and (ii) evaluate the potential of regeneration and recycle of the chelating agent for multiple uses. Conventionally, ethylenediamine-tetraacetic acid (EDTA) has been studied extensively to remove ash from biomass. However, EDTA is non-biodegradable and causes environmental issues at the disposal.

Nitrilotriacetic acid (NTA) is a biodegradable chelating agent and was used in this study for …

Numerical Modeling Of Shoreline Response To Storm Tides And Sea Level Rise, Akash Sahu

Civil & Environmental Engineering Theses & Dissertations

In this study, an integrated hydrodynamic, wave, and sediment transport modeling approach is developed for predicting the spatiotemporal variation of erosion of a sandy shoreline due to storm surge, wave action, tidal variations, and relative sea level rise (RSLR). The study site is located at the northern most portion of the city of Norfolk, Virginia, and it is of importance to the city, both in terms of tourism and for the protection that it provides for upland properties against storms. The region, in general, experiences the highest rate of RSLR on the U.S. East Coast which should result in high …

Challenges Of Designing And Operating A Pilot Scale Short Residence Time Continuous Hydrothermal Flash Hydrolysis Reactor For High Slurry Load Biomass Processing, Mason James Martin

Civil & Environmental Engineering Theses & Dissertations

Increasing demand for renewable energy, fuels, and bioproducts has resulted in a push for increasingly efficient and economically favorable biomass pretreatment methods. Flash Hydrolysis, (FH) a promising biomass pretreatment method, has been extensively studied at a laboratory scale. FH employs a continuous subcritical hydrothermal process capable of fractionating microalgae for lipid and protein recovery. FH is unique in that the residence time is very short (~ 10 s). Maintaining this residence time was key in designing a scaled pilot flash hydrolyzing unit (FHU). We have developed a one of its kind pilot FHU capable of increasing the processing output of …

Numerical Modeling And Field Investigation Of Nearshore Nonlinear Wave Propagation, Elham Sharifineyestani

Civil & Environmental Engineering Theses & Dissertations

First, a phase-resolving frequency-domain wave model that solves nonlinear wave-wave interactions is improved to account for wave dissipation and modulations over viscoelastic mud layer. Model results show satisfactory agreement with laboratory measurements. The model is then used to investigate the combined effect of mud viscoelasticity and nonlinear wave-wave interactions on surface wave evolution using cnoidal and random wave simulations. In general, qualitative measures such as shape of cnoidal waves or pattern of variation in H_rms of random waves are dictated by direct mud-induced damping which, due to resonance effects, has a substantially different structure over viscoelastic mud compared to …

Adaptive Control Of Base Isolation Systems Using The Transmissibility-Based Semi-Active Controller, Ramin Rabiee

Civil & Environmental Engineering Theses & Dissertations

Base isolation system is one of the most effective seismic protection systems which is widely used to protect buildings of high importance against seismic hazards. However, the performance of these systems might be impaired under long-period earthquake ground motions due to the resonance effect. The main focus of this dissertation is the development of an adaptive semi-active control algorithm to improve the performance of conventional base isolation systems. The proposed control law works based on the transmissibility theory, called the transmissibility-based semi-active (TSA) controller, which can adaptively change the damping of the base-isolation system based on the response of the …

Deep Reinforcement Learning Approach For Lagrangian Control: Improving Freeway Bottleneck Throughput Via Variable Speed Limit, Reza Vatani Nezafat

Civil & Environmental Engineering Theses & Dissertations

Connected vehicles (CVs) will enable new applications to improve traffic flow. The focus of this dissertation is to investigate how reinforcement learning (RL) control for the variable speed limit (VSL) through CVs can be generalized to improve traffic flow at different freeway bottlenecks. Three different bottlenecks are investigated: A sag curve, where the gradient changes from negative to positive values causes a reduction in the roadway capacity and congestion; a lane reduction, where three lanes merge to two lanes and cause congestion, and finally, an on-ramp, where increase in demand on a multilane freeway causes capacity drop. An RL algorithm …

Developing Algorithms To Detect Incidents On Freeways From Loop Detector And Vehicle Re-Identification Data, Biraj Adhikari

Civil & Environmental Engineering Theses & Dissertations

A new approach for testing incident detection algorithms has been developed and is presented in this thesis. Two new algorithms were developed and tested taking California #7, which is the most widely used algorithm to date, and SVM (Support Vector Machine), which is considered one of the best performing classifiers, as the baseline for comparisons. Algorithm #B in this study uses data from Vehicle Re-Identification whereas the other three algorithms (California #7, SVM and Algorithm #A) use data from a double loop detector for detection of an incident. A microscopic traffic simulator is used for modeling three types of incident …

Next-Generation Rainfall Idf Curves For The Virginian Drainage Area Of Chesapeake Bay, Xixi Wang, Xiaomin Yang, Zhaoyi Cai

Civil & Environmental Engineering Faculty Publications

Probability-based intensity-duration-frequency IDF curves are needed but currently lacking for Department of Defense DoD to construct and manage its infrastructure in changing climate. The objectives of this project were to 1 develop an innovative approach for considering rainfall non-stationarity in developing such IDF curves and 2 apply this approach to the state of Virginia. In this regard, the observed data on 15-min rainfall at 57 gauges and the precipitations projected by twelve pairs of Regional Climate Model RCM and Global Circulation Model GCM were used. For a given gauge or watershed, in terms of fitting the empirical exceedance probabilities, a …

Variable Speed Limit Control At Sag Curves Through Connected Vehicles: Implications Of Alternative Communications And Sensing Technologies, Reza Vatani Nezafat

Civil & Environmental Engineering Theses & Dissertations

Connected vehicles (CVs) will enable new applications to improve traffic flow. This study’s focus is to investigate how potential implementation of variable speed limit (VSL) through different types of communication and sensing technologies on CVs may improve traffic flow at a sag curve. At sag curves, the gradient changes from negative to positive values which causes a reduction in the roadway capacity and congestion. A VSL algorithm is developed and implemented in a simulation environment for controlling the inflow of vehicles to a sag curve on a freeway to minimize delays and increase throughput. Both vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V) …

Measuring And Modeling Bare Desert Wind Erosion From Steppe Grassland Of Northern China As Affected By Soil Moisture And Climate, Nicholas Morgan Potter

Civil & Environmental Engineering Theses & Dissertations

Soil erosion by wind has been found to be negatively related to soil water content, as evidenced by that for a given area, such a soil erosion can be much less in a wet than a dry year. However, few studies have examined the functional relationship between wind erosion and soil moisture, primarily due to lack of field measured data. The objectives of this study were to: 1) measure wind erosion in field using a portable wind tunnel devised and made by the author; 2) use the measured data to calibrate/validate a wind erosion model previously developed by the author; …

Latent Choice Models To Account For Misclassification Errors In Discrete Transportation Data, Lacramioara Elena Balan

Civil & Environmental Engineering Theses & Dissertations

One of the most fundamental tasks when it comes to analyzing data using statistical methods is to understand the relationship between the explanatory variables and the outcome. Misclassification of explanatory variables is a common risk when using statistical modeling techniques. In this dissertation, we define ‘misclassification,’ as a response that is reported or recorded in the wrong category; for example, a variable is registered as a one when it should have the value zero. Misclassification can easily happen in any data; for example, in an interview setting where the respondent misunderstands the question or the interviewer checks the wrong box. …

Sidestream Ras Fermentation For Stable Bio-P Combined With Short Cut Nitrogen Removal In An A/B Process, Lindsey Elise Ferguson

Civil & Environmental Engineering Theses & Dissertations

It is well known that soluble organic carbon (sCOD), especially in the form of volatile fatty acids (VFA), is critical to achieving reliable enhanced biological phosphorus removal (EBPR) in biological nutrient removal (BNR) processes. Consistent and reliable EBPR in systems treating wastewaters deficient in sCOD may be accomplished by the addition of VFA and sCOD – rich fermentate produced by the fermentation of primary sludge, return / waste activated sludge (RAS / WAS), or other suitable carbon sources. The solids retention time (SRT) of fermenters being used to supplement carbon in sidestream EBPR processes must be controlled such that complex …

The Resilient City: A Platform For Informed Decision-Making Process, Paul Niculescu-Mizil Gheorghe, Jarutpong Vasuthanasub, Adrian Gheorghe

Engineering Management & Systems Engineering Faculty Publications

As over half of the world’s inhabitants lives in metropolises, the rapid growth in urbanization has made cities becoming more and more exposed and vulnerable to a broad spectrum of threats and hazards. In order to respond to such difficulties, a concept of resilience is considered a significant component for the long-term planning and sustainable development of the cities. “Resilient City” is a new paradigm that challenges the idealistic principle of stability and resistance to change implicitly in sustainable development and success. However, building a resilient city requires a holistic approach, as well as the appropriate adoption of knowledge and …

Notched Hollow Square Section Steel Column Buckling, Zia Razzaq, Solomon Tecleab

Civil & Environmental Engineering Faculty Publications

Presented in this paper is an outcome of a study to assess the effect of section loss in the form of longitudinal notches on the buckling load of hollow square section steel columns. The theoretical study includes buckling load estimates based on both an iterative equilibrium as well as a non-iterative energy approach. Buckling loads based on sample laboratory experiments are also presented. The study shows that the presence of a notch can significantly reduce the axial load-carrying capacity of a steel column.

Tsunamigenic Potential Of The Baiyun Slide Complex In The South China Sea, Linlin Li, Fengyan Shi, Gangfeng Ma, Qiang Qiu

Civil & Environmental Engineering Faculty Publications

The Baiyun slide complex contains geological evidence for some of the largest landslide ever discovered in the continental slopes of the South China Sea. High-resolution seismic data suggest that a variety of landslides with varied scales have occurred repeatedly in this area. The largest landslide reconstructed from bathymetric and seismic data has an estimated spatial coverage of ~5,500 km² and a conservative volume of ~1,035 km³. Here, using geomorphological and geotechnical data, we construct a series of probable landslide scenarios and assess their tsunamigenic capacity. By treating the slides as deformable mudflows, we simulate the dynamics of …

Improving Stem Recruitment Through A Theme-Based Summer Residential Camp Focused On Sea Level Rise, Vukica M. Jovanović, Balša Terzić, Mujde Erten-Unal, Victoria Hill, George Mcleod, Michelle Covi, David Burdige, Jenifer Alonzo, Justin Mason, Tysha Batts, Cynthia Tomovic

Engineering Technology Faculty Publications

In this paper, the authors present an enrichment program that focuses on Science, Technology, Engineering, and Math (STEM) concepts. The program is named Building Leaders to Advance Science and Technology (BLAST) and is held each summer at three universities across the Commonwealth of Virginia: Old Dominion University, the University of Virginia, and the Virginia Polytechnic Institute. BLAST is sponsored in partnership among these three universities and the Virginia Space Grant Consortium (VSGC), and is funded by the General Assembly of Commonwealth of Virginia. Its main purpose is to expose high school students to topics related to different STEM fields through …