Engineering Commons^™

Formulation And Validation Of Nanoparticle Controlled Delivery For Chemotherapeutic Drug Products, Shani L. Levit

Theses and Dissertations

Taxol, a formulation of paclitaxel (PTX), is one of the most widely used anticancer drugs, particularly for treating recurring ovarian carcinomas following surgery. Clinically, PTX is used in combination with other drugs such as lapatinib (LAP) to increase treatment efficacy. Delivering drug combinations with nanoparticles has the potential to improve chemotherapy outcomes. In this study, we use Flash NanoPrecipitation, a rapid, scalable process to encapsulate weakly hydrophobic drugs (logP in vitro. Encapsulating either PTX or LAP into nanoparticles increases drug potency. When PTX and LAP are co-loaded in the same nanoparticle, they have a synergistic effect that is greater than …

Systematic Model-Based Design Assurance And Property-Based Fault Injection For Safety Critical Digital Systems, Athira Varma Jayakumar

Theses and Dissertations

With advances in sensing, wireless communications, computing, control, and automation technologies, we are witnessing the rapid uptake of Cyber-Physical Systems across many applications including connected vehicles, healthcare, energy, manufacturing, smart homes etc. Many of these applications are safety-critical in nature and they depend on the correct and safe execution of software and hardware that are intrinsically subject to faults. These faults can be design faults (Software Faults, Specification faults, etc.) or physically occurring faults (hardware failures, Single-event-upsets, etc.). Both types of faults must be addressed during the design and development of these critical systems. Several safety-critical industries have widely adopted …

Strategies And Devices For Improving Respiratory Drug Delivery To Infants And Children With Cystic Fibrosis, Karl Bass

Theses and Dissertations

Cystic Fibrosis (CF) is a degenerative disease, which causes thickening of the airway surface liquid and reduced mucociliary clearance, which provides an ideal habitat for bacterial infections. Early treatment of CF in children can prevent chronic infection, improve quality of life, and increase life expectancy. The most predominant bacteria found in CF-diseased lungs is Pseudomonas aeruginosa (Pa), which can be treated with inhaled tobramycin. Excipient enhanced growth (EEG) powder formulations are well suited for administering tobramycin to children, as the EEG approach provides minimal upper airway loss and targeted drug delivery. This method uses an initially small aerosol for high …

Mathematical Models Of Cellular Signaling And Supramolecular Self-Assembly, Pratip Rana

Theses and Dissertations

Synthetic biologists endeavor to predict how the increasing complexity of multi-step signaling cascades impacts the fidelity of molecular signaling, whereby cellular state information is often transmitted with proteins diffusing by a pseudo-one-dimensional stochastic process. We address this problem by using a one-dimensional drift-diffusion model to derive an approximate lower bound on the degree of facilitation needed to achieve single-bit informational efficiency in signaling cascades as a function of their length. We find that a universal curve of the Shannon-Hartley form describes the information transmitted by a signaling chain of arbitrary length and depends upon only a small number of physically …

Structure, Morphology And Composition-Property Elucidation Of Ni–Mo And Ni−Mo−P Nanocrystals For Water Splitting Reactions And Group Iv Alloy And Silicate Nanocrystals For Visible To Near Ir Optoelectronics, Ebtesam Hassan Abuelenein Eladgham

Theses and Dissertations

Abstract

Structure, Morphology and Composition-Property Elucidation of Ni–Mo and Ni−Mo−P Nanocrystals for Water Splitting Reactions and Group IV Alloy and Silicate Nanocrystals for Visible to Near IR Optoelectronics

by

Ebtesam Hassan Abuelenein Eladgham

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Advisor: Indika U Arachchige

Associate Professor, Department of Chemistry

Nanomaterials have gained a great attention because of their unique physical properties with size intermediate between molecular materials and extended solids. They have a large surface to volume ratio and display size tunable physical properties that was not …

On-Demand Electrically Induced Decomposition Of Thin-Film Nitrocellulose Membranes For Wearable Or Implantable Biosensor Systems, Benjamin M. Horstmann

Theses and Dissertations

Implantable or subcutaneous biosensors used for continuous health monitoring have a limited functional lifetime requiring frequent replacement and therefore may be highly discomforting to the patient and become costly. One possible solution to this problem is use of biosensor arrays where each individual reserve sensor can be activated on-demand when the previous one becomes inoperative due to biofouling or enzyme degradation. Each reserve biosensor in the array is housed in an individual Polydimethylsiloxane (PDMS) well and is protected from exposure to bodily fluids such as interstitial fluid ( ISF) by a thin-film nitrocellulose membrane. Controlled activation is achieved by decomposing …

Development Of A Torque-Based Device For The Quantification Of Arm Rigidity In Patients With Parkinson’S Disease, Georgina O. Miller

Theses and Dissertations

Parkinsonian rigidity is caused by the inability of the muscles to relax and extend properly, due to reduced dopamine levels and often begins on one side of the body before spreading contralaterally. The current standard for determining joint rigidity in a clinical setting is a test completed by the clinician based on the feel of the relaxed wrist and elbow joints as they are passively flexed and extended and a series of ordinal rating scales, the Movement Disorder Society’s – Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Hoehn and Yahr Scale (H&Y), and Parkinson’s Disease Questionnaire-39 (PDQ-39). These methods are used …

Implementation Of A Hierarchical, Embedded, Cyber Attack Detection System For Spi Devices On Unmanned Aerial Systems, Jeremy J. Price

Theses and Dissertations

Unmanned Aerial Systems (UAS) create security concerns as their roles expand in commercial, military, and consumer spaces. The need to secure these systems is recognized in the architecture for a Hierarchical, Embedded, Cyber Attack Detection (HECAD) system. HECAD passively monitors the communication between a flight controller and all its peripherals like sensors and actuators. It ensures the functionality of a UAS is within the set of defined behavior and reports all potential problems, whether the errors were caused by cyber attacks or other physical faults. A portion of the design for Serial Peripheral Interface (SPI) devices on board a flight …

Reaction Profiling Of Extracellular Protein Phosphorylation Through A Microfluidic Reactor Coupled With Raman Spectroscopy, Abigail Casey

Theses and Dissertations

Diseases and disorders in the human body are considered abnormalities of proper cellular function. Understanding the signal transduction mechanisms that cause these abnormalities is crucial to developing earlier detection methods, better treatment options and effective cures. While current diagnostic procedures are powerful tools in diagnosing diseases, they are ineffective in informing physicians on the real-time behavior of the signal transduction mechanisms associated with diseases and disorders. Currently, disease progression is monitored over time through routine patient visits and testing by one or more of the above techniques. By developing an approach that can monitor structural and conformational changes of proteins …

Dendrimer-Based Therapeutic Delivery Vehicle For The Treatment Of Ocular Diseases, Remy C. Cooper

Theses and Dissertations

The treatment of ocular diseases poses a significant challenge to drug delivery design, due to the eye’s complex anatomy, with a semi-permeable blood-ocular barrier and associated immune privilege. To address some of the delivery challenges, polycationic dendrimers are explored as vehicle for the treatment of posterior chamber disease. Dendrimers are a class of polymeric nanoparticles that are highly branched, multivalent and monodisperse, whose three-dimensional globular architecture has given them the nickname of “synthetic proteins”. Dendrimers are synthesized by reacting monomers in a step-wise fashion to produce generationally and radially increasing structures, with core, interior and surface chains that are highly …

Improving Grid Hosting Capacity And Inertia Response With High Penetration Of Renewable Generation, Hamidreza Sadeghian

Theses and Dissertations

To achieve a more sustainable supply of electricity, utilizing renewable energy resources is a promising solution. However, the inclusion of intermittent renewable energy resources in electric power systems, if not appropriately managed and controlled, will raise a new set of technical challenges in both voltage and frequency control and jeopardizes the reliability and stability of the power system, as one of the most critical infrastructures in the today’s world. This dissertation aims to answer how to achieve high penetration of renewable generations in the entire power system without jeopardizing its security and reliability. First, we tackle the data insufficiency in …

The Impact Of Aging And Mechanical Injury On Alveolar Epithelial And Macrophage Responses In Acute Lung Injury And Inflammation, Michael S. Valentine

Theses and Dissertations

Patients with severe lung pathologies, such as Acute Respiratory Distress Syndrome (ARDS), often require mechanical ventilation as a clinical intervention; however, this procedure frequently exacerbates the original pulmonary issue and produces an exaggerated inflammatory response that potentially leads to sepsis, multisystem organ failure, and mortality. This acute lung injury (ALI) condition has been termed Ventilator-Induced Lung Injury (VILI). Alveolar overdistension, cyclic atelectasis, and biotrauma are the primary injury mechanisms in VILI that lead to the loss of alveolar barrier integrity and pulmonary inflammation. Stress and strains during mechanical ventilation are believed to initiate alveolar epithelial mechanotransduction signaling mechanisms that contribute …

Optical Spectroscopy And Theoretical Modelling Of Carrier Dynamics In Group-Iv Alloy Quantum Dots, Rahnuma Rahman

Theses and Dissertations

In recent years, Ge_1−xSn_x alloy quantum dots (QDs) have attracted significant interest due to their potential applications in photodetectors and light emitting devices in visible to mid IR spectral range and compatibility with silicon based platforms. While bulk Ge is an indirect bandgap semiconductor (0.66 eV), direct transitions can be made possible by incorporation of α-Sn at concentrations of ~10%, which however lowers the bandgap. Utilizing quantum confinement by reducing the size to below the Bohr radius also promotes direct transitions and more importantly increases the fundamental transition energies in GeSn alloy QDs, making them suitable for …

Sound Propagation In Viscous Flows Using Piezoelectric Sensors And Non-Destructive Propagation Techniques And Its Applications, Ahmed M. Abdulkareem

Theses and Dissertations

Structural non-destructive evaluation techniques are applied to viscous flows to detect fluid property changes. The main operating principle consists of an actuator which provides a stimulus, and a sensor to receive a signal traveling to a fluid domain. The main challenge of the operating principle consists of investigating waves traveling in a viscous flow. Traveling waves utilizing a piezoelectric actuator-sensor pair are modeled and the results are validated experimentally. ANSYS models, coupled with a two-way fluid-solid interaction model, are built to investigate how far a signal travels and what frequency ranges are of interest. The numerical model includes modeling three …

Beneficiation Of Coal Using Supercritical Water And Carbon Dioxide Extraction, Matthew Decuir Virginia Commonwealth University Cl

Theses and Dissertations

This work explores the use of carbon dioxide, water, and their mixtures as solvent for the pre-combustion beneficiation of raw coal without using any toxic mineral acids in the temperature range of 200-400℃. The fluid polarity, ionic constant, and supercritical point can be adjusted by H₂O/CO₂ ratio and temperature. Adding carbon dioxide to hydrothermal fluid also increases the ionization by forming carbonic acid. Extractions with supercritical fluids have several benefits including enhanced mass transport, ease of separation and recycle, wide range of extractive capability and tunability, better inherent safety, and in the case of carbon dioxide and …

Data Science Methods For Standardization, Safety, And Quality Assurance In Radiation Oncology, Khajamoinuddin Syed

Theses and Dissertations

Radiation oncology is the field of medicine that deals with treating cancer patients through ionizing radiation. The clinical modality or technique used to treat the cancer patients in the radiation oncology domain is referred to as radiation therapy. Radiation therapy aims to deliver precisely measured dose irradiation to a defined tumor volume (target) with as minimal damage as possible to surrounding healthy tissue (organs-at-risk), resulting in eradication of the tumor, high quality of life, and prolongation of survival. A typical radiotherapy process requires the use of different clinical systems at various stages of the workflow. The data generated in these …

Self-Assembled Metal Nanoparticle/Polymer Nanocomposites As Nanoreactors For One-Pot Reactions, Andrew Harrison

Theses and Dissertations

Polymer nanoreactors incorporating gold nanoparticle catalysts were self-assembled via Flash Nanoprecipitation. The incorporated gold nanoparticles maintained catalytic activity, which was evaluated using reduction of 4-nitrophenol with sodium borohydride as a model reaction. The diffusion coefficient for 4-nitrophenol was determined by NMR and used to calculate the second Damköhler number, which indicated that the systems were not diffusion limited. Despite similar diffusion coefficients, catalytic performance was strongly affected by the co-precipitant. For example, the apparent reaction rate per surface area using castor oil was over 8-fold greater than polystyrene. Thus, we measured the partition coefficient of 4-nitrophenol between water and castor …

Reducing Material Attractiveness Utilizing Pu-238 And U-232, Cody Lloyd

Theses and Dissertations

Decreasing the material attractiveness of uranium and plutonium materials is crucial to nuclear nonproliferation. The International Atomic Energy Agency (IAEA) implements safeguards across the world on a limited budget. Not only does decreasing material attractiveness reduce the possibility of proliferation, but also may lighten the financial burden on the IAEA if safeguards can be reduced. Two particular isotopes that have negative material attractiveness traits are ²³⁸Pu and ²³²U. Without isotopic separation technology, these isotopes cannot be removed from plutonium and uranium materials respectively. Both ²³⁸Pu and ²³²U produce large quantities of heat by alpha decay. High …

Multilevel Runtime Verification For Safety And Security Critical Cyber Physical Systems From A Model Based Engineering Perspective, Smitha Muralidhar Gautham

Theses and Dissertations

Advanced embedded system technology is one of the key driving forces behind the rapid growth of Cyber-Physical System (CPS) applications. CPS consists of multiple coordinating and cooperating components, which are often software-intensive and interact with each other to achieve unprecedented tasks. Such highly integrated CPSs have complex interaction failures, attack surfaces, and attack vectors that we have to protect and secure against. This dissertation advances the state-of-the-art by developing a multilevel runtime monitoring approach for safety and security critical CPSs where there are monitors at each level of processing and integration. Given that computation and data processing vulnerabilities may exist …

Exploiting Feedback Information In Cognitive Radio Systems, Sara Abozeid Attlla

Theses and Dissertations

In this thesis, we consider a cognitive radio (CR) network where the primary network's feedback information is utilized to design access schemes for the secondary network, to exploit the underutilized primary spectrum resources. Secondary users (SUs) identify the spectrum opportunities by sensing the spectrum for primary users (PUs) activities and by listening to the PUs feedback. The feedback signals monitored in this research work are the channel quality indicator (CQI) and automatic repeat request (ARQ) available in the PUs network. For detecting the PUs activities, SUs employ hard/soft energy sensing. The secondary access decisions are optimized to maximize the SUs …

Using Nano- And Micro- Structural Materials For Concrete Environmental Applications, Hala Nabeel Elia

Theses and Dissertations

Utilized globally in the construction industry, concrete is an integral component of homes, roads, airports, skyscrapers, and tunnels. Traditional concrete components are cement, fine aggregate (sand), coarse aggregate (gravel or crushed stone), and water. When cement and water compound together they will make a paste which binds all the aggregates together to make the concrete. Unfortunately, every one ton of cement manufactured emits 0.9 ton of CO2into the air. The goal of this two-part work was to obtain an environmentally friendly concrete. The first part used supplementary cementitious materials (SCM), fly ash and silica fume, to create concrete with high …

Multiple Agent Target Tracking In Gps-Denied Environments, Skyler Tolman

Theses and Dissertations

Unmanned aerial systems (UAS) are effective for surveillance and monitoring, but struggle with persistent, long-term tracking, especially without GPS, due to limited flight time. Persistent tracking can be accomplished using multiple vehicles if one vehicle can effectively hand off the tracking information to another replacement vehicle. This work presents a solution to the moving-target handoff problem in the absence of GPS. The proposed solution (a) a nonlinear complementary filter for self-pose estimation using only an IMU, (b) a particle filter for relative pose estimation between UAS using a relative range (c) visual target tracking using a gimballed camera when the …

Analysis Of Applied Modifications To A Cone Penetration Test-Based Lateral Spread Displacement Prediction Model, Alexander Edward Corob

Theses and Dissertations

This study set out to examine the effectiveness and reliability of six modifications to the Zhang et al. (2004) CPT-based lateral spread model. A regression analysis, distribution charts, and a discriminant analysis are performed to determine how effective the modifications are on the model. From the comparisons and statistical analysis performed in this study, application of these modifications reduces over-predictions from strain-based prediction methods. Unfortunately, the tendency to under-predict displacements on average is also increased.

Bending Behavior Of Concrete Beams With Fiber/Epoxy Composite Rebar, Kolten Dewayne Rice

Theses and Dissertations

This research explores the use of carbon/epoxy and fiberglass/epoxy fiber-reinforced polymer (FRP) composite rebar manufactured on a three-dimensional braiding machine for use as reinforcement in concrete beams under four-point bending loads. Multiple tows of prepreg composite fibers were pulled to form a unidirectional core. The core was consolidated with spirally wound Kevlar fibers which were designed to also act as ribs to increase pullout strength. The rebar was cured at 121â—¦C (250â—¦F) in an inline oven while keeping tension on the fibers. Five configurations of reinforcing bars were used in this study as reinforcement in concrete beam specimens: carbon/epoxy rebar …

Characterization And Modeling Of The Martensite Transformation In Advanced High-Strength Steels, Stephen Roy Cluff

Theses and Dissertations

Multiple studies on the microstructures of advanced high-strength steels are presented here that seek to add to the already substantial body of knowledge on martensite in steel. These studies seek to gain additional insight into the role that the martensite transformation has on the observed mechanical properties of modern steels. Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include …

Machine Learning On Acoustic Signals Applied To High-Speed Bridge Deck Defect Detection, Yao Chou

Theses and Dissertations

Machine learning techniques are being applied to many data-intensive problems because they can accurately provide classification of complex data using appropriate training. Often, the performance of machine learning can exceed the performance of traditional techniques because machine learning can take advantage of higher dimensionality than traditional algorithms. In this work, acoustic data sets taken using a rapid scanning technique on concrete bridge decks provided an opportunity to both apply machine learning algorithms to improve detection performance and also to investigate the ways that training of neural networks can be aided by data augmentation approaches. Early detection and repair can enhance …

An Exploration Of Neural Networks In Enhanced Resolution Remote Sensing Products, Jordan Paul Brown

Theses and Dissertations

Scatterometry and radiometry are used to obtain measurements of Earth properties with extensive spatial coverage at daily or near-daily temporal resolution. Their measurements are used in many climate studies and weather applications, such as iceberg tracking, ocean wind estimation, and volumetric soil moisture measurements. The spatial resolution of these data products ranges from a few kilometers to tens of kilometers. Techniques to enhance the spatial resolution of these products help reveal finer scale features, but come at the cost of increased noise. This thesis explores the application of neural networks as a possible method to handle the noise and uncertainty …

Near-Coastal Ultrahigh Resolution Scatterometer Winds, Nolan Lawrence Hutchings

Theses and Dissertations

RapidScat 2.5 km ultrahigh resolution (UHR) wind estimation is introduced and validated it in near-coastal regions. In addition, this thesis applies direction interval retrieval techniques and develops a new wind processing method to enhance the performance of RapidScat UHR wind estimation in the nadir region. The new algorithm is validated with L2B wind estimates, Numerical Weather Prediction (NWP) wind products, and buoy measurements. The wind processing improvements produce more spatially consistent UHR winds that compare well with the wind products mentioned above. Hawaii regional climate model (HRCM), QuikSCAT, and ASCAT wind estimates are compared in the lee of the Big …

Cuo/Cu Core/Shell Nanostructured Photoconductive Devices By Hwt And Hips, Khalidah Hussein Habeeb Al-Mayalee

Theses and Dissertations

Over recent years, great efforts are being dedicated to developing low cost and high-efficiency nanostructured design for optoelectronic applications. Nanostructured semiconductor materials have demonstrated superior performance as compared to bulk materials. Core/shell nanostructured geometries have received a great deal of attention not only in the area of synthesis and characterization but also in their potential applications. These structures have been used in abundance in various areas such as electronics, sensors, catalysis, biomedical, and optical devices. Well-controlled core/shell nanostructured geometries can offer a significant improvement in the devices' performance. Therefore, the fabrication of complex 3D core/shell architectures with controlled morphology, homogeneous …

Vertical Electrical Impedance Measurements Of Concrete Bridge Decks, Jared Scott Baxter

Theses and Dissertations

This research focuses on the creation, validation, automation, and deployment of a nondestructive vertical electrical impedance (VEI) bridge deck assessment apparatus. A multichannel impedance analyzer with a moving platform is developed that can assess the deterioration state of a bridge deck without stationary traffic control. The multichannel apparatus is capable of taking over 500 impedance samples a second and can scan a bridge deck over 500 times faster than more traditional techniques. This research also shows VEI measurements are inversely proportional to the diffusivity of ions through concrete and that an impedance measurement frequency of 25 kHz is the most …