Physical Sciences and Mathematics Commons^™

Light Soaking Phenomena In Organic-Inorganic Mixed Halide Perovskite Single Crystals, Hye Ryung Byun, Dae Young Park, Hye Min Oh, Gon Namkoong, Mun Seok Jeong

Electrical & Computer Engineering Faculty Publications

Recently, organic inorganic mixed halide perovskite (MAPbX₃; MA = CH₃NH₃^+, X = Cl^-, Br^-, or I^-) single crystals with low defect densities have been highlighted as candidate materials for high-efficiency photovoltaics and optoelectronics. Here we report the optical and structural investigations of mixed halide perovskite (MAPbBr_3-xI_x) single crystals. Mixed halide perovskite single crystals showed strong light soaking phenomena with light illumination conditions that were correlated to the trapping and detrapping events from defect sites. By systematic investigation with optical analysis, we found that the …

Femtosecond Laser Induced Structural Dynamics And Melting Of Cu (111) Single Crystal. An Ultrafast Time-Resolved X-Ray Diffraction Study, Runze Li, Omar A. Ashour, Jie Chen, H. E. Elsayed-Ali, Peter M. Rentzepis

Electrical & Computer Engineering Faculty Publications

Femtosecond, 8.04 keV x-ray pulses are used to probe the lattice dynamics of a 150 nm Cu (111) single crystal on a mica substrate irradiated with 400 nm, 100 fs laser pulses. For pump fluences below the damage and melting thresholds, we observed lattice contraction due to the formation of a blast force and coherent acoustic phonons with a period of ∼69 ps. At larger pump fluence, solid to liquid phase transition, annealing, and recrystallization were measured in real time by monitoring the intensity evolution of the probing fs x-ray rocking curves, which agreed well with theoretical simulation results. The …

Deep Models For Engagement Assessment With Scarce Label Information, Feng Li, Guangfan Zhang, Wei Wang, Roger Xu, Tom Schnell, Jonathan Wen, Frederic Mckenzie, Jiang Li

Electrical & Computer Engineering Faculty Publications

Task engagement is defined as loadings on energetic arousal (affect), task motivation, and concentration (cognition) [1]. It is usually challenging and expensive to label cognitive state data, and traditional computational models trained with limited label information for engagement assessment do not perform well because of overfitting. In this paper, we proposed two deep models (i.e., a deep classifier and a deep autoencoder) for engagement assessment with scarce label information. We recruited 15 pilots to conduct a 4-h flight simulation from Seattle to Chicago and recorded their electroencephalograph (EEG) signals during the simulation. Experts carefully examined the EEG signals and labeled …

Teaching Hands-On Cyber Defense Labs To Middle School And High School Students: Our Experience From Gencyber Camps, Peng Jiang, Xin Tian, Chunsheng Xin, Wu He

Electrical & Computer Engineering Faculty Publications

With the high demand of the nation for next generation cybersecurity experts, it is important to design and provide hands-on labs for students at the K-12 level in order to increase their interest in cybersecurity and enhance their confidence in learning cybersecurity skills at the young age. This poster reports some preliminary analysis results from the 2016 GenCyber summer camp held at Old Dominion University (ODU), which is part of a nationwide grant program funded by the National Security Agency (NSA) and the National Science Foundation (NSF). This poster also demonstrates the design of three hands-on labs which have been …

Qos Recommendation In Cloud Services, Xianrong Zheng, Li Da Xu, Sheng Chai

Information Technology & Decision Sciences Faculty Publications

As cloud computing becomes increasingly popular, cloud providers compete to offer the same or similar services over the Internet. Quality of service (QoS), which describes how well a service is performed, is an important differentiator among functionally equivalent services. It can help a firm to satisfy and win its customers. As a result, how to assist cloud providers to promote their services and cloud consumers to identify services that meet their QoS requirements becomes an important problem. In this paper, we argue for QoS-based cloud service recommendation, and propose a collaborative filtering approach using the Spearman coefficient to recommend cloud …

An Example Of Nature's Mathematics: The Rainbow, John A. Adam

Mathematics & Statistics Faculty Publications

No abstract provided.

A New Formulation Of Time Boundary Integral Equation For Acoustic Wave Scattering In The Presence Of A Uniform Mean Flow, Fang Q. Hu, Michelle E. Pizzo, Douglas M. Nark

Mathematics & Statistics Faculty Publications

It has been well-known that under the assumption of a constant uniform mean flow, the acoustic wave propagation equation can be formulated as a boundary integral equation, in both the time domain and the frequency domain. Compared with solving partial differential equations, numerical methods based on the boundary integral equation have the advantage of a reduced spatial dimension and, hence, requiring only a surface mesh. However, the constant uniform mean flow assumption, while convenient for formulating the integral equation, does not satisfy the solid wall boundary condition wherever the body surface is not aligned with the uniform mean flow. In …

Observations And Operational Model Simulations Reveal The Impact Of Hurricane Matthew (2016) On The Gulf Stream And Coastal Sea Level, Tal Ezer, Larry P. Atkinson, Robert Tuleya

CCPO Publications

In October 7–9, 2016, Hurricane Matthew moved along the southeastern coast of the U.S., causing major flooding and significant damage, even to locations farther north well away from the storm’s winds. Various observations, such as tide gauge data, cable measurements of the Florida Current (FC) transport, satellite altimeter data and high-frequency radar data, were analyzed to evaluate the impact of the storm. The data show a dramatic decline in the FC flow and increased coastal sea level along the U.S. coast. Weakening of the Gulf Stream (GS) downstream from the storm’s area contributed to high coastal sea levels farther north. …

Editorial-The 6th International Workshop On Modeling The Ocean (Iwmo 2014), Lie-Yauw Oey, Tal Ezer, Jinyu Sheng, Fei Chai, Jianping Gan, Kevin Lamb

CCPO Publications

The 6th International Workshop on Modeling the Ocean (IWMO 2014) was held on June 23–27, 2014, at Dalhousie University in Halifax, Nova Scotia, Canada. After three meetings in Asia (Oey et al. 2010, 2013a, b) and one in Europe (Berntsen et al. 2014), the IWMO returned to North America for the second time (since IWMO 2010 in the USA; Ezer et al. 2011). Readers are referred to https://www.dal.ca/sites/iwmo. html for more information on IWMO 2014 and http://www. ccpo.odu.edu/POMWEB /meetings.htm for information on the past meetings and future planned meetings.

Back-Flow Prevention Strategies For Stormwater Lines, Ron Evins

September 29, 2016: Adaptive Structures and Innovative Solutions

No abstract provided.

Emily Steinhilber Column: Virginia's Leadership In Flood Resilience, Emily E. Steinhilber

News Items

No abstract provided.

Plasma Processes And Polymers Third Special Issue On Plasma And Cancer, Mounir Laroussi, Annemie Bogaerts, Nazir Barekzi

Electrical & Computer Engineering Faculty Publications

(First paragraph) This issue of Plasma Processes and Polymers is the third in a series on the applications of low temperature plasma (LTP) against cancer, or “plasma oncology.” The papers in this issue are inspired from the talks given at the third International Workshop on Plasma for Cancer Treatment (IWPCT) which took place on April 11–12, 2016 in Washington, DC, USA. IWPCT is an international workshop that was created in 2014 as a venue to share cutting edge plasma oncology research. The first IWPCT was held in Washington DC, under the co-chairmanship of Prof. Mounir Laroussi (Old Dominion University) and …

Version 1.3 Aim Sofie Measured Methane (Ch4): Validation And Seasonal Climatology, P. P. Rong, J. M. Russell Iii, B. T. Marshall, D. E. Siskind, M. E. Hervig, L. L. Gordley, P. F. Bernath, K. A. Walker

Chemistry & Biochemistry Faculty Publications

The V1.3 methane (CH₄) measured by the Aeronomy of Ice in the Mesosphere (AIM) Solar Occultation for Ice Experiment (SOFIE) instrument is validated in the vertical range of ~25–70 km. The random error for SOFIE CH₄ is ~0.1–1% up to ~50 km and degrades to ~9% at ∼ 70 km. The systematic error remains at ~4% throughout the stratosphere and lower mesosphere. Comparisons with CH₄ data taken by the SCISAT Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) and the Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) show an agreement within ~15% in the altitude range ~30–60 …

Commonwealth Center For Recurrent Flooding Resiliency: An Update, Morris Foster, John Wells

Commonwealth Center for Recurrent Flooding Resiliency (CCRFR): Presentations

October 17th, 2016 Update to Joint Subcommittee on Coastal Flooding. PDF of powerpoint presentation.

Protecting The Most Vulnerable, Joshua G. Behr

VMASC Publications

No abstract provided.

Circulation, Vol. 22, No. 1, Center For Coastal Physical Oceanography, Old Dominion University, Mike Dinniman

CCPO Circulation

Fall 2016 issue of CCPO Circulation featuring article "I have to Do What to the Model? How Did I Get Here, Part ll" by Mike Dinniman.

Hampton Roads Sea Level Rise Preparedness And Resilience Intergovernmental Pilot Project. Phase 2 Report: Recommendations, Accomplishments And Lessons Learned, Emily E. Steinhilber, Maura Boswell, Carol Considine, Larry Mast

Hampton Roads Intergovernmental Pilot Project: Reports

Executive Summary

After two years, the Hampton Roads Sea level Rise and Resilience Intergovernmental Planning Pilot Project (Intergovernmental Pilot Project or IPP), convened at Old Dominion University, has come to a successful close. Although the conclusion of the project is different than originally imagined by the drafters of the IPP Charter, the process in and of itself brought hundreds of stakeholders together, built lasting and ongoing relationships, and produced many workable recommendations for the region that can be accomplished by a variety of partnerships. The key deliverables include a whole of government mitigation and adaptation planning process and an integrated …

Coastal Groundwater Watch: A Citizen Science Project - Report No. 477, Alex Manda, Thomas Allen

Political Science & Geography Faculty Publications

The goals of this study were to utilize citizen scientists in groundwater research in a coastal community where groundwater plays a large role in sustainable water resources management, and assess the extent of groundwater and marine inundation in response to future sea-level rise scenarios. A total of 7 citizen scientists participated in the study by measuring water levels from 15 groundwater monitoring wells using water level meters once a week over a 10-week period. Automated water level loggers were deployed in three of the same wells to assess the quality of the data collected by the citizen scientists. Additional water …

Distributions Of Euphausia Superba, Euphausia Crystallorophias, And Pleuragramma Antarcticum With Correlations To Environmental Variables In The Western Ross Sea, Antarctica, Linnea Brynn Davis

OES Theses and Dissertations

Antarctic krill (Euphausia superba), crystal krill (Euphausia crystallorophias), and Antarctic silverfish (Pleuragramma antarcticum) are key mid-trophic level species in the Ross Sea food web that provide connectivity between primary production and the upper trophic levels. Distributions of these species were constructed from net-based and acoustic observations collected in the western Ross Sea from 1988-2004. Distributions of environmental conditions in the Ross Sea were obtained from a high-resolution circulation model (temperature, mixed layer depth, surface speed) and satellite-derived observations (chlorophyll, sea ice cover). These distributions were analyzed with a range of statistical methods to determine …

Multiple Imputation Of Missing Data In Structural Equation Models With Mediators And Moderators Using Gradient Boosted Machine Learning, Robert J. Milletich Ii

Psychology Theses & Dissertations

Mediation and moderated mediation models are two commonly used models for indirect effects analysis. In practice, missing data is a pervasive problem in structural equation modeling with psychological data. Multiple imputation (MI) is one method used to estimate model parameters in the presence of missing data, while accounting for uncertainty due to the missing data. Unfortunately, commonly used MI methods are not equipped to handle categorical variables or nonlinear variables such as interactions. In this study, we introduce a general MI framework that uses the Bayesian bootstrap (BB) method to generate posterior inferences for indirect effects and gradient boosted machine …

Potential Impacts Of Climate Change On Photochemistry Of Zostera Marina L., Billur Celebi

OES Theses and Dissertations

Seagrasses account for approximately 10% of the ocean’s total carbon storage, although photosynthesis of seagrasses is carbon limited at today’s oceanic pH. Therefore, increasing atmospheric CO₂ concentration, which results in ocean acidification/carbonation, is predicted to have a positive impact on seagrass productivity. Previous studies have confirmed the positive influence of increasing CO₂ on photosynthesis and survival of the temperate eelgrass Zostera marina L., but the acclimation of photoprotective mechanisms in this context has not been characterized. This study aimed to quantify the long-term impacts of ocean acidification on photochemical control mechanisms that promote photosynthesis while simultaneously protecting …

Bioenergetics: Experimental Demonstration Of Excess Protons And Related Features, Haitham A. Saeed

Chemistry & Biochemistry Theses & Dissertations

Over the last 50 years, ever since the Nobel-prize work of Peter Mitchell’s Chemiosmotic theory, the question whether bioenergetics energy transduction occurs through localized or delocalized protons has been a controversial issue among scientists. Recently, a proton-electrostatics localization hypothesis was formulated which may provide a new and clear understanding of localized and delocalized proton-coupling energy transduction in many biological systems. The aim of this dissertation was to test this new hypothesis.

To demonstrate the fundamental behavior of localized protons in a pure water-membrane-water system in relation to the newly derived pmf equation, excess protons and excess hydroxyl anions were generated …

Preface-Jes Focus Issue On Electrolysis For Increased Renewable Energy Penetration, B. Pivovar, M. Carmo, K. Ayers, X. Zhang, J. O'Brien

Mechanical & Aerospace Engineering Faculty Publications

(First paragraph) Today represents a particularly exciting time, as our planet’s energy system is undergoing major changes due to dramatically decreasing renewable energy prices and increasing societal concerns over greenhouse gas emissions, criteria pollutants (arsenic, mercury, NOx, particulate matter), and climate change. These factors are pushing society toward deep decarbonization of our energy system, perhaps the most challenging issue facing the planet today. Unfortunately, wind and solar energy, while both promising generation sources, come with intermittency challenges and have limitations in their abilities to impact industrial and transportation sector demands where fossil fuel energy carriers based on chemical bonds have …

Exploring New Models For Seatbelt Use In Survey Data, Mark K. Ledbetter, Norou Diawara, Bryan E. Porter

Virginia Journal of Science

Problem: Several approaches to analyze seatbelt use have been proposed in the literature. Two methods that has not been explored are the use of unweighted and weighted logistic regression model and the use of item response theory (IRT) or the Rasch model. Since accurate methods to predict seatbelt use behavior based upon observed data must include a built-in design method and model, and overcome computation challenges, weighted and IRT method deem to be other options for an observational survey of seat belt use in the state of Virginia.

Method: The observed data from 136 sites within the Commonwealth …

Simulation And Optimization Of Ant Colony Optimization Algorithm For The Stochiastic Uncapacitated Location-Allocation Problem, Jean-Paul Arnaout, Georges Arnaout, John El Khoury

Engineering Management & Systems Engineering Faculty Publications

This study proposes a novel methodology towards using ant colony optimization (ACO) with stochastic demand. In particular, an optimizationsimulation-optimization approach is used to solve the Stochastic uncapacitated location-allocation problem with an unknown number of facilities, and an objective of minimizing the fixed and transportation costs. ACO is modeled using discrete event simulation to capture the randomness of customers’ demand, and its objective is to optimize the costs. On the other hand, the simulated ACO’s parameters are also optimized to guarantee superior solutions. This approach’s performance is evaluated by comparing its solutions to the ones obtained using deterministic data. The results …

Impact Of Upper-Tropospheric Temperature Anomalies And Vertical Wind Shear On Tropical Cyclone Evolution Using An Idealized Version Of The Operational Gfdl Hurricane Model, Robert E. Tuleya, Morris Bender, Thomas R. Knutson, Joseph R. Sirutis, Biju Thomas, Isaac Ginis

CCPO Publications

The GFDL hurricane modeling system, initiated in the 1970s, has progressed from a research tool to an operational system over four decades. This system is still in use today in research and operations, and its evolution will be briefly described. This study used an idealized version of the 2014 GFDL model to test its sensitivity across a wide range of three environmental factors that are often identified as key factors in tropical cyclone (TC) evolution: SST, atmospheric stability (upper-air thermal anomalies), and vertical wind shear (westerly through easterly). A wide range of minimum central pressure intensities resulted (905-980 hPa). The …

Longitudinal Tidal Dispersion Coefficient Estimation And Total Suspended Solids Transport Characterization In The James River, Beatriz Eugenia Patino

Civil & Environmental Engineering Theses & Dissertations

The longitudinal dispersion coefficient is a parameter used to evaluate the effect of cross-sectional variations on substance mixing mechanisms in estuaries influenced by tide, wind and internal density variations. Considering a two dimensional approach, this study aims at evaluating a tidal area of the lower James River at approximately 19 miles upstream from the mouth at the Chesapeake Bay, in the City of Newport News, and applies an experimental procedure based on in-situ salinity concentrations to estimate the dispersion coefficient in the area where receives a discharge from the HRSD James River Wastewater Treatment Plant, and further characterizes Total Suspended …

Investigation Of Multi-Photon Excitation In Argon With Applications In Hypersonic Flow Diagnostics, Jack L. Mills

Physics Theses & Dissertations

Non-intrusive flow diagnostics are essential for studying the physics of hypersonic flow wake regions. To advance the development of next generation hypersonic vehicles and to improve computational fluid dynamics techniques in the hypersonic regime, NASA needs a suitable non-intrusive diagnostic technique to measure velocity, density, and temperature. We will present our work on developing a seedless, non-intrusive diagnostic technique using excited state argon atoms, prepared via multi-photon excitation. In this dissertation, we report results on the first phase of this hypersonic wake measurement project. In particular, we have redesigned and characterized the performance of a high energy, nanosecond pulsed Ti:Sapphire …

Effects Of Surrounding Water Table On A Forested Wetland Habitat In East Coast Of Virginia, Lane Stokes

Civil & Environmental Engineering Theses & Dissertations

Exchanges into and out of a wetland, including surface water flow, groundwater flow, and constituents in the flows, usually determine the wetland physicochemical characteristics and biodiversity. To date, of these three exchanges, groundwater flow is the least studied, particularly in the United States of America. In this thesis, field observations were conducted at a forested non-tidal wetland, located on a flat hilltop. The position of the wetland is such that groundwater outflow is the only significant exchange that could be impacted by the surrounding land use. In addition, a spatially variable steady-state model was set up to extrapolate the observations …

Changing Trends In Wave Heights In The U.S. Mid-Atlantic Region, Hillary Lane

Civil & Environmental Engineering Theses & Dissertations

The pace and effects of climate change are an area of constant focus for coastal engineers as evolving patterns in the atmosphere worldwide affect the oceans and coasts on a regional and global scale. Surface waves respond to changing wind patterns both locally and from propagating swell, and the difficulty in predicting future wind patterns is well-established. Expectations that climate change will result in more frequent and intense coastal storms and consequently greater wave heights in the North Atlantic are still unrealized, and recent forecasts from a variety of atmosphere-ocean coupled global climate models instead predict decreasing wave heights through …