Engineering Commons^™

Current-Driven Production Of Vortex-Antivortex Pairs In Planar Josephson Junction Arrays And Phase Cracks In Long-Range Order, Francisco Estellés-Duart, Miguel Ortuño, Andrés M. Somoza, Valerii M. Vinokur, Alex Gurevich

Physics Faculty Publications

Proliferation of topological defects like vortices and dislocations plays a key role in the physics of systems with long-range order, particularly, superconductivity and superfluidity in thin films, plasticity of solids, and melting of atomic monolayers. Topological defects are characterized by their topological charge reflecting fundamental symmetries and conservation laws of the system. Conservation of topological charge manifests itself in extreme stability of static topological defects because destruction of a single defect requires overcoming a huge energy barrier proportional to the system size. However, the stability of driven topological defects remains largely unexplored. Here we address this issue and investigate numerically …

Illuminator, Volume 2, Issue 1, Batten College Of Engineering And Technology, Old Dominion University

College of Engineering & Technology Newsletter

September 2018 issue of Illuminator, a monthly publication of ODU's Batten College of Engineering and Technology.

Voltage Effects On Muscarinic Acetylcholine Receptor-Mediated Contractions Of Airway Smooth Muscle, Iurii Semenov, Robert Brenner

Bioelectrics Publications

Studies have shown that the activity of muscarinic receptors and their affinity to agonists are sensitive to membrane potential. It was reported that in airway smooth muscle (ASM) depolarization evoked by high K⁺ solution increases contractility through direct effects on M3 muscarinic receptors. In this study, we assessed the physiological relevance of voltage sensitivity of muscarinic receptors on ASM contractility. Our findings reveal that depolarization by high K⁺ solution induces contraction in intact mouse trachea predominantly through activation of acetylcholine release from embedded nerves, and to a lesser extent by direct effects on M3 receptors. We therefore devised …

Moderate Heat Application Enhances The Efficacy Of Nanosecond Pulse Stimulation For The Treatment Of Squamous Cell Carcinoma, Chelsea M. Edelblute, Sigi Guo, Embo Yang, Chunqi Jiang, Karl Schoenbach, Richard Heller

Bioelectrics Publications

Nanosecond pulse stimulation as a tumor ablation therapy has been studied for the treatment of various carcinomas in animal models and has shown a significant survival benefit. In the current study, we found that moderate heating at 43°C for 2 minutes significantly enhanced in vitro nanosecond pulse stimulation-induced cell death of KLN205 murine squamous cell carcinoma cells by 2.43-fold at 600 V and by 2.32-fold at 900 V, as evidenced by propidium iodide uptake. Furthermore, the ablation zone in KLN205 cells placed in a 3-dimensional cell-culture model and pulsed at a voltage of 900 V at 43°C was 3 times …

Accurate Flexible Refinement Of Atomic Models Against Medium-Resolution Cryo-Em Maps Using Damped Dynamics, Julio A. Kovacs, Vitold E. Galkin, Willy Wriggers

Mechanical & Aerospace Engineering Faculty Publications

Background: Dramatic progress has recently been made in cryo-electron microscopy technologies, which now make possible the reconstruction of a growing number of biomolecular structures to near-atomic resolution. However, the need persists for fitting and refinement approaches that address those cases that require modeling assistance.

Methods: In this paper, we describe algorithms to optimize the performance of such medium-resolution refinement methods. These algorithms aim to automatically optimize the parameters that define the density shape of the flexibly fitted model, as well as the time-dependent damper cutoff distance. Atomic distance constraints can be prescribed for cases where extra containment of parts of …

Antimicrobial Efficacy And Safety Of A Novel Gas Plasma-Activated Catheter Lock Solution, Sudhir Bhatt, Poonam Mehta, Chen Chen, Dayle A. Daines, Leonard A. Mermel, Hai-Lan Chen, Michael G. Kong

Bioelectrics Publications

Antimicrobial lock solutions are important for prevention of microbial colonization and infection of long-term central venous catheters. We investigated the efficacy and safety of a novel antibiotic-free lock solution formed from gas plasma-activated disinfectant (PAD). Using a luminal biofilm model, viable cells of methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Candida albicans in mature biofilms were reduced by 6 to 8 orders of magnitude with a PAD lock for 60 min. Subsequent 24-h incubation of PAD-treated samples resulted in no detectable regrowth of viable bacteria or fungi. As a comparison, the use of a minocycline-EDTA-ethanol lock solution for 60 …

Editorial For The Special Issue On Micro/Nano-Chip Electrokinetics, Volume Ii, Xiangchun Xuan, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

There has been a rapidly increasing interest in the use of micro/nanofluidics to develop various point-of-care technologies for global health [1,2]. Electrokinetics is often the method of choice in these micro/nano-chips for an accurate transport and manipulation of fluids and samples [3,4]. This special issue in Micromachines is the continuation of our successful first volume on Micro/Nano-Chip Electrokinetics [5]. It consists of 22 contributions, which cover multiple aspects of electrokinetics related phenomena for various chemical and biological applications. We divide these papers into three primary categories and summarize them briefly below.

Illuminator, Volume 1, Issue 10, Batten College Of Engineering & Technology, Old Dominion University

College of Engineering & Technology Newsletter

Summer 2018 issue of Illuminator, a monthly publication of ODU's Batten College of Engineering and Technology.

Solid Oxide Electrochemical Cells For High Temperature Hydrogen Production: Theory, Fabrication And Characterization, Can Zhou

Mechanical & Aerospace Engineering Theses & Dissertations

In this dissertation, the concept of water splitting using solid oxide photoelectrochemical cells (SOPCs) at high temperature was introduced and experimentally investigated. High temperature photoelectrochemical water splitting physically broadens the selection of potential applicable semiconductor materials and enables more visible sunlight absorption. This newly conceived concept provides a unique pathway for solar hydrogen production, as compared to conventional photoelectrochemical cells (PECs) that use wide band gap semiconductors in aqueous environments. The theoretical framework of SOPC was elaborated, followed by the experimental investigation to search for appropriate high temperature materials. Selected high temperature Schottky and p-n junction diodes, which were expected …

Aerothermodynamic Analysis Of A Mars Sample Return Earth-Entry Vehicle, Daniel A. Boyd

Mechanical & Aerospace Engineering Theses & Dissertations

Because of the severe quarantine constraints that must be imposed on any returned extraterrestrial samples, the Mars sample return Earth-entry vehicle must remain intact through sample recovery. Vehicles returning on a Mars-Earth trajectory will attain velocities exceeding any that have been experienced by prior space exploration missions, with velocities approaching 14 km/s. Velocities as high as these will encounter significant heating during atmospheric re-entry to Earth.

The purpose of this study has been to systematically investigate the aerothermodynamic challenges that will result from a Mars sample return, Earth-entry vehicle design. The goal was to enable efficient estimation of maximum stagnation …

A Stepwise Compression-Relaxation Testing Method For Tissue Characterization And Tumor Detection Via A Two-Dimensional Tactile Sensor, Yichao Yang

Mechanical & Aerospace Engineering Theses & Dissertations

This dissertation presents a stepwise compression-relaxation (SCR) testing method built upon a two-dimensional (2D) tactile sensor for mechanical characterization of soft tissues and tumor detection. The core of the 2D sensor entails one whole polydimethylsiloxane (PDMS) microstructure embedded with a 3×3 sensing-plate/transducer array. A soft sample was compressed by the 2D sensor with a step incremental depth at a ramp speed, and then relaxed for certain hold time. When a soft sample was compressed by the 2D sensor, the sensing-plates translated the sample response at different tissue sites to the sensor deflections, which were registered as resistance changes by the …

Optimization Of Top Contact For Cu(In,Ga)Se2 Solar Cells, Grace Cherukara Rajan

Electrical & Computer Engineering Theses & Dissertations

As world energy demands continue to increase, the need to generate electricity from a broader variety of sources, including renewables, is more critical than ever. With costs still 30% higher than those of natural gas, solar energy is a viable contender, but more progress is needed to level the playing field with other forms of energy generation. The overall energy security can be enhanced by diversifying the energy supply. Among them, Cu(In,Ga)Se₂ (CIGS) has gained significant momentum as a possible high efficiency and low cost thin film solar cell material. The capacity to scale up any photovoltaic technology is …

Generation Of Large-Volume Diffuse Plasma By An External Ionization Wave From A Single-Electrode Plasma Jet, Seyed Hamid Razavi Barzoki

Electrical & Computer Engineering Theses & Dissertations

A non-thermal transient diffuse plasma can be generated remotely in a nonconductive reduced pressure chamber by an external guided fast ionization wave (FIW). We found that an atmospheric-pressure low-temperature plasma jet (APPJ) can be a source of FIW which transfers an enhanced electric field at the wave front across a reduced pressure Pyrex glass chamber with no electrical connection to the chamber. Here, we studied the formation and propagation of the APPJ plasma, the interaction of atmospheric-pressure guided FIW with a dielectric surface which forms the wall of the reduced-pressure system, and the formation and propagation of the reduce-pressure FIW …

Non-Destructive Evaluation For Composite Material, Desalegn Temesgen Delelegn

Electrical & Computer Engineering Theses & Dissertations

The Nondestructive Evaluation Sciences Branch (NESB) at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) has conducted impact damage experiments over the past few years with the goal of understanding structural defects in composite materials. The Data Science Team within the NASA LaRC Office of the Chief Information Officer (OCIO) has been working with the Non-Destructive Evaluation (NDE) subject matter experts (SMEs), Dr. Cheryl Rose, from the Structural Mechanics & Concepts Branch and Dr. William Winfree, from the Research Directorate, to develop computer vision solutions using digital image processing and machine learning techniques that can help identify …

Analysis Of Bulk Power System Resilience Using Vulnerability Graph, Md Ariful Haque

Computational Modeling & Simulation Engineering Theses & Dissertations

Critical infrastructure such as a Bulk Power System (BPS) should have some quantifiable measure of resiliency and definite rule-sets to achieve a certain resilience value. Industrial Control System (ICS) and Supervisory Control and Data Acquisition (SCADA) networks are integral parts of BPS. BPS or ICS are themselves not vulnerable because of their proprietary technology, but when the control network and the corporate network need to have communications for performance measurements and reporting, the ICS or BPS become vulnerable to cyber-attacks. Thus, a systematic way of quantifying resiliency and identifying crucial nodes in the network is critical for addressing the cyber …

Developmental Steps For A Functional Three-Dimensional Cell Culture System For The Study Of Asymmetrical Division Of Neural Stem Cells, Martina Zamponi

Biomedical Engineering Theses & Dissertations

Stem cells are a cell type present during and following development, which possess self- renewal properties, as well as the ability to differentiate into specific cells. Asymmetrical division is the cellular process that allows stem cells to produce one differentiated and one un-differentiated daughter cell during the same mitotic event. Insights in the molecular mechanisms of such process are minimal, due to the absence of effective methods for its targeted study. Currently, traditional methods of investigation include monolayer cell culture and animal models. The first poses structural limitations to the accurate representation of human tissue and cell structures, while animal …

Epithelial Sheet Response To External Stimuli, Yashar Bashirzadeh

Mechanical & Aerospace Engineering Theses & Dissertations

Mechanical communication of adherent cells with their micro-environment is mediated by cytoskeletal and adhesion proteins. These mechanical links aid tissues in maintaining their coherence in the context of the surrounding extra cellular matrix (ECM). Epithelial tissues exert force on the ECM through integrin-based junctions and maintain their coherency through E-cadherin-based cell-cell junctions while dynamically undergoing collective migration. Such a complex network of communication involving the cell cytoskeleton and adhesion proteins modulates the tissue's response to external cues. Two distinct forms of such external stimuli are those of electrical and mechanical origin.

Epithelial tissues quickly respond to physiologically relevant electric fields …

Identification And Optimal Linear Tracking Control Of Odu Autonomous Surface Vehicle, Nadeem Khan

Mechanical & Aerospace Engineering Theses & Dissertations

Autonomous surface vehicles (ASVs) are being used for diverse applications of civilian and military importance such as: military reconnaissance, sea patrol, bathymetry, environmental monitoring, and oceanographic research. Currently, these unmanned tasks can accurately be accomplished by ASVs due to recent advancements in computing, sensing, and actuating systems. For this reason, researchers around the world have been taking interest in ASVs for the last decade. Due to the ever-changing surface of water and stochastic disturbances such as wind and tidal currents that greatly affect the path-following ability of ASVs, identification of an accurate model of inherently nonlinear and stochastic ASV system …

The Influence Of Engineers On Public Policy, Sarah Bouazzaoui

Engineering Management & Systems Engineering Theses & Dissertations

Engineers play a vital role in society and contribute positively to economic growth in various areas, including energy, transportation, telecommunications, and others. In the United States of America, these areas are monitored by public policies that are set by policy actors—mainly lawyers, public administrators and social scientists—at legislative and regulatory levels. In these domains, engineers have a reduced voice with key decision makers on critical engineering issues, and their input is very limited. Their lack of involvement results in costly unintended consequences, affecting both the interest of the profession and the interest of the nation.

Research has shown that increased …

Model-Less Fuzzy Logic Control For The Nasa Modeling And Control For Agile Aircraft Development Program, Keith A. Benjamin

Electrical & Computer Engineering Theses & Dissertations

The NASA Modeling and Control for Agile Aircraft Development (MCAAD) program seeks to develop new ways to control unknown aircraft to make the aircraft development cycle more efficient. More specifically, there is a desire to control an aircraft with an unknown mathematical model using only first principles of flight. In other words, rather than using a rigorously developed mathematical model combined with wind-tunnel tests, a controller is sought which would allow one to bypass the development of a rigorous mathematical model and enter wind-tunnel testing more directly. This paper presents the design of a fuzzy PID controller, governed by a …

Effects Of Automated Fiber Placement On High Strain Rate Compressive Response Of Advanced Composites, Alexander Trochez

Mechanical & Aerospace Engineering Theses & Dissertations

Automated Fiber Placement (AFP) technology shows great promise in manufacturing carbon fiber composite structures. However, intermittent defects occur in the process that can affect the overall mechanical performance of the structure. The aim of this work is to investigate the effects of deliberately placed principal defects (Gap, Overlap, and Fold) on the compressive response under quasistatic (strain rate ~10^-3 s^-1) and dynamic (strain rate ~10³ s-1) loading conditions. The controlled defects were placed at the laminate level in different orientations and depths. High strain rate compression experiments were conducted using a split Hopkinson pressure bar (SHPB) …

A Representation Of Tactical And Strategic Precursors Of Supply Network Resilience Using Simulation Based Experiments, Yaneth C. Correa-Martinez

Engineering Management & Systems Engineering Theses & Dissertations

Modern supply chains are becoming increasingly complex and are exposed to higher levels of risk. Globalization, market uncertainty, mass customization, technological and innovation forces, among other factors, make supply networks more susceptible to disruptions (both those that are man-made and/or ones associated with natural events) that leave suppliers unavailable, shut-down facilities and entail lost capacity.

Whereas several models for disruption management exist, there is a need for operational representations of concepts such as resilience that expand the practitioners’ understanding of the behavior of their supply chains. These representations must include not only specific characteristics of the firm’s supply network but …

A Framework For Executable Systems Modeling, Matthew Amissah

Engineering Management & Systems Engineering Theses & Dissertations

Systems Modeling Language (SysML), like its parent language, the Unified Modeling Language (UML), consists of a number of independently derived model languages (i.e. state charts, activity models etc.) which have been co-opted into a single modeling framework. This, together with the lack of an overarching meta-model that supports uniform semantics across the various diagram types, has resulted in a large unwieldy and informal language schema. Additionally, SysML does not offer a built in framework for managing time and the scheduling of time based events in a simulation.

In response to these challenges, a number of auxiliary standards have been offered …

Sequence-Based Simulation-Optimization Framework With Application To Port Operations At Multimodal Container Terminals, Mariam Aladdin Kotachi

Engineering Management & Systems Engineering Theses & Dissertations

It is evident in previous works that operations research and mathematical algorithms can provide optimal or near-optimal solutions, whereas simulation models can aid in predicting and studying the behavior of systems over time and monitor performance under stochastic and uncertain circumstances. Given the intensive computational effort that simulation optimization methods impose, especially for large and complex systems like container terminals, a favorable approach is to reduce the search space to decrease the amount of computation.

A maritime port can consist of multiple terminals with specific functionalities and specialized equipment. A container terminal is one of several facilities in a port …

Illuminator, Volume 1, Issue 9, Batten College Of Engineering & Technology

College of Engineering & Technology Newsletter

June 2018 issue of Illuminator, a monthly publication of ODU's Batten College of Engineering and Technology.

Mechanism Of Virus Inactivation By Cold Atmospheric-Pressure Plasma And Plasma-Activated Water, Li Guo, Ruobing Xu, Lu Gou, Zhichao Liu, Yiming Zhao, Dingxin Liu, Lei Zhang, Hailan Chen, Michael G. Kong

Bioelectrics Publications

ABSTRACT Viruses cause serious pathogenic contamination that severely affects the environment and human health. Cold atmospheric-pressure plasma efficiently inactivates pathogenic bacteria; however, the mechanism of virus inactivation by plasma is not fully understood. In this study, surface plasma in argon mixed with 1% air and plasma-activated water was used to treat water containing bacteriophages. Both agents efficiently inactivated bacteriophages T4, ϕ174, and MS2 in a time-dependent manner. Prolonged storage had marginal effects on the antiviral activity of plasma-activated water. DNA and protein analysis revealed that the reactive species generated by plasma damaged both nucleic acids and proteins, consistent with the …

Creating The Fleet Maker - Lessons Learned From The First Series Of Workshops On Maker Concepts For Active Duty Personnel, Karina Arcaute, Michel Albert Audette, Vukica Jovanovic, Anthony Dean, Dipankar Ghosh

STEMPS Faculty Publications

The US Navy has supported research related to the 3D printing or Additive Manufacturing area for more than 20 years. More recently, efforts like the Print the Fleet initiative and Marine Makers are exploring ways to design and create solutions to future problems with the possibility of reducing maintenance costs, increasing equipment readiness, and improving combat effectiveness. The Creating the Fleet Maker project is an effort supported by the Navy and Marine Corps Science, Technology, Engineering and Mathematics Education, Outreach and Workforce Program of the Office of Naval Research. It examines the concept of making in order to develop skills …

Incorporating Diegetic Elements To Increase Engagement In Games For Engineering Education, Katherine Smith, Yuzhong Shen, Anthony W. Dean

VMASC Publications

One of the difficulties in developing educational games is maintaining player engagement. This engagement is critical for games to provide effective learning experiences. One way to increase engagement in games is to limit interruptions during game play. In educational games, this can be accomplished by incorporating learning or problem-solving elements diegetically. Diegetic elements are those that are part of the game scene. With this in mind, a series of games for Science, Technology, Engineering, and Mathematics (STEM) education has been developed focusing on content in courses that are prerequisites to the engineering curriculum. These games cover topics in pre-calculus, calculus, …

Integrating Statistical Methods In Engineering Technology Courses, Sanjeevi Chitikeshi, Jake Hildebrant, Otilia Popescu, Orlando M. Ayala, Vukica M. Jovanovic

Engineering Technology Faculty Publications

Statistical methods and procedures are very important in engineering applications. In most of the engineering fields electronic devices are used as sensing and controlling components. Lack of proper calibration of these devices and of performance analysis using different statistical methods may lead to erroneous measurements and results. In medical or manufacturing areas such errors in the experimental results could be catastrophic. Applying different statistical tests and procedures enhance the quality of engineering work. Traditionally, most engineering curricula have at least one required course in applied statistics in engineering, but that is not generally the case in engineering technology programs. Most …

Introduction Of Mechatronics Specialization Through Concentration Areas In The Mechanical And Electrical Engineering Technology Programs, Otilia Popescu, Vukica M. Jovanovic, Sanjeevi Chitikeshi, Isaac L. Flory Iv

Engineering Technology Faculty Publications

The last few decades have experienced an explosion of technology, both in industry and in customer products. A large variety of embedded systems from various areas of applications, digital electronics, internet of things, automatically controlled products, and ultimately mechatronics systems are part of the everyday life. The changes in the industries, consumer markets and implicitly in the job markets, impose changes in the academic programs and curricula. Recently, mechatronics undergraduate programs started being developed in 2 or 4 years colleges across the nation, mainly driven by international companies operating in countries that already offer mechatronics degrees ranging from high school …