Engineering Commons^™

Molecular Modeling Of Sigma 1 And Sigma 2 Receptor Ligands: Pharmacophore Development And Comparison Using Discotech And Bioactivity Prediction Comparison Of Ab Initio And Density Functional Comfa Studies For Spiro And Other Receptor Ligands, Lisa M. Kardos

Dissertations

The role of the biological receptor is currently being studied by researchers in medicine. Information about sigma receptors in particular can be gained by studying the ligands associated with each type, sigma 1 or sigma 2. Sigma 1 receptor ligands consist of drug candidates that often have psychiatric and neurological applications; sigma 2 receptor ligands consist of drug candidates that have been linked with cancer treatment among other applications.

Molecular modeling of biological receptor ligands often encompasses pharmacophore development and Comparative Molecular Field Analysis (CoMFA). Pharmacophore models are developed to understand the unique features such as binding groups that make …

Reliability Study Of Zr And Al Incorporated Hf Based High-K Dielectric Deposited By Advanced Processing, Md Nasir Uddin Bhuyian

Dissertations

Hafnium-based high-x dielectric materials have been successfully used in the industry as a key replacement for SiO₂ based gate dielectrics in order to continue CMOS device scaling to the 22-nm technology node. Further scaling according to the device roadmap requires the development of oxides with higher x values in order to scale the equivalent oxide thickness (EOT) to 0.7 nm or below while achieving low defect densities. In addition, next generation devices need to meet challenges like improved channel mobility, reduced gate leakage current, good control on threshold voltage, lower interface state density, and good reliability. In order to …

Optical Properties Of Strain-Engineered Multilayer Si/Sige Nanostructures, Selina Akter Mala

Dissertations

The long carrier radiative lifetimes in indirect band gap semiconductors such as crystalline Si (c-Si) and Ge impede the development of efficient light-emitting devices and lasers. Multilayer Si/SiGe nanostructures are considered to be the strong candidates for efficient and high-speed optoelectronic devices integrated into CMOS platforms. Since c-Si and Ge have a considerable lattice mismatch of ~ 4.2%, Si/Si_1-xGe_x(x < 0.5) nanostructures in the form of nano-layers (NLs) or cluster multilayers (CMs) modify the band structure and create non-uniform strain distribution. Engineering of Si/Si_1-xGe_xnanostructures with the predicted composition and interface abruptness, which controls spatial separation between electrons and holes and carrier radiative recombination rate, is critical in producing the desired fast and efficient photoluminescence …

Electronic, Optical, Mechanical And Thermoelectric Properties Of Graphene, Sarang Vilas Muley

Dissertations

Graphene, a two-dimensional allotrope of graphite with sp² bonded carbon atoms, is arranged in honeycomb structure. Its quasi one-dimensional form is graphene nanoribbon (GNR). Graphene related materials have been found to display excellent electronic, chemical, mechanical properties along with uniquely high thermal conductivity, electrical conductivity and high optical transparency. With excellent electrical characteristics such as high carrier transport properties, quantum Hall effect at room temperature and unusual magnetic properties, graphene has applications in optoelectronic devices.

Electronically, graphene is a zero bandgap semiconductor making it essential to tailor its structure for obtaining specific band structure. Narrow GNRs are known to …

Monitoring Of Cerebellar Injury Using Micro Ecog Signals In Ketamine/Xylazine Treated Rats, Gokhan Ordek

Dissertations

Much of the cerebellar research has been conducted in anesthetized animals, particularly using ketamine/xylazine combination in rats, and yet the absolute impact of the anesthesia on the neural circuit remains unanswered . In the current study, spontaneous electrical activity and sensory evoked potentials from the cerebellar surface with chronically implanted, flexible-substrate, multielectrode arrays in rats were collected and analyzed with the motor cortex signals. The power spectra and the intercontact coherence plots of the spontaneous activity in the awake-quiet animals extended up to 800 Hz in the cerebellum and only up to 200 Hz in the motor cortex. Ketamine/xylazine anesthesia …

Modeling Biodegradation Settlement Of Municipal Solid Waste (Msw) Based On Measurement Of Landfill Gas And Degradable Solids In Leachate Recirculated Bioreactors, Vatsal Atulkumar Shah

Dissertations

The purpose of this work is two-fold: 1) to understand the phenomenon of the biodegradation process of municipal solid waste (MSW) in leachate recirculated bioreactors, and 2) to create a realistic predictive model based on this understanding which is capable of supporting a laboratory-to-field relationship for bioreactor landfills. Biodegradation is best described by loss of mass; however, primary researchers have assumed the phenomenon to be purely volume loss and modeled best by mechanical processes using a conservation of energy approach. It is suggested that the phenomenon requires a fundamental understanding of biodegradation process which results in a loss of mass, …

Developing An Insulin Producing Tissue Using Mouse Embryonic Stem Cells, Neha Mahendrakumar Jain

Dissertations

This thesis describes derivation of pancreatic insulin producing cells (IPCs) from mouse embryonic stem cells and development of three-dimensional (3D) engineered tissue system to provide physiologic culture conditions for IPCs. Upon using a previously established protocol, IPCs have been successfully derived from mouse embryonic stem cells and characterized in vitro . IPCs not only express classical markers of pancreatic beta cells but also exhibit glucose responsive behavior. Interestingly while deriving IPCs from mouse embryonic stem cells, islet endothelial cells have also been identified and successfully isolated from the culture. Derivation of a pure population of endothelial cells expressing specific markers …

Expert System For Energy Optimization Of Buildings Using Sustainable And Resilient Strategies, Victoria Ann Scala

Dissertations

An expert system is developed using the science of heuristics to better model energy usage in existing commercial buildings and to predict future improvements more accurately. The software performs an initial audit analysis of all the major building systems including building envelope, HVAC, lighting, office equipment and appliances, water and hot water, and waste handling. A novel feature of the expert system is that it analyzes energy flow within the building more interactively and cohesively, as opposed to looking at each system individually as do most energy analysis tools on the current market. Both forward and backward chaining strategies are …

Inkjet Printing Multifunctional Chromatic Sensors And Chromism Study, Aide Wu

Dissertations

The thermochromism and chemochromism of polydiacetylene (PDAs) and PDA/ZnO nano composites have been systematically studied by attentuated total reflection (ATR)- Fourier transform infrared (FTIR), temperature-dependent Raman, colorimetric (using optical densitometry) and differential scanning calorimetry (DSC). Reversibility of PDAs has been enhanced by the formation of chelation between the carboxylic groups on side chain of diacetylene and Zn ion. The thermochromatic transition temperature increases with the concentration of ZnO.

Thin films of polydiacetylene (PDAs) and PDA/ZnO nanocomposites have been successfully fabricated by inkjet printing both solution type and suspension type ink. Results suggest that PDA monomers are well-aligned and closely packed …

Continuous Polymer Coating Of Host Particles By Hollow Fiber-Based Crystallizers, Dengyue Chen

Dissertations

Currently, no technique is available to continuously film coat nano-sized drug particles with a polymer to produce large amounts of free-flowing coated particles. In this work, Eudragit RL 100 and Poly (D, L-lactide-co-glycolide) (PLGA) are chosen as the coating polymers; Cosmo 55 (550 nm silica particles), Aerosi l 200 (hydrophilic 12 nm silica), Aerosil R974 (hydrophobic 12 nm silica) and Griseofulvin (10 lam drug particles) are chosen as the host particles. Two novel crystal l izers are designed and fabricated to continuously coat the host particles with different polymers: solid hollow fiber cooling crystallizer (SH FCC) and porous hollow fiber …

Polymeric Nitrogen By Plasma Enhanced Chemical Vapor Deposition, El Mostafa Benchafia

Dissertations

With the urgent need for new environmentally-friendly energetic materials, the field of polymeric nitrogen, predicted to be a high energy density energetic, is now at a critical stage in its development. In spite of extensive first principles calculations regarding the existence and stability of different polymeric nitrogen structures, their successful syntheses have been rare. This dissertation describes the first detailed study of a plasma-enhanced chemical vapor deposition (PECVD) approach to the synthesis of polymeric nitrogen. PECVD provides non-equilibrium conditions known to produce high pressure-temperature phases. Molecular nitrogen mixed with hydrogen and argon is used as the gas phase precursor to …

An Analysis Of The Predictive Capability Of C5.0 And Chaid Decision Trees And Bayes Net In The Classification Of Fatal Traffic Accidents In The Uk, Aiden O'Connor

Dissertations

Road traffic accidents are a significant cause of deaths worldwide and there is a global focus on understanding accident contributory factors and implementing prevention strategies. Although accident statistics are steadily improving, effective prevention must be persistent, evidence based and properly resourced. This research aimed to extract fatal traffic accident prediction from UK STATS19 accident data using C5.0 and Chaid decision trees and Bayes net classification models. Data was grouped as either fatal or non-fatal. The class imbalance due to fatal accident infrequency was considered and data transformation and sampling techniques were applied to increase prediction likelihood. Chaid was used for …

Adaptive Control For Autonomous Navigation Of Mobile Robots Considering Time Delay And Uncertainty, Stephen Kofi Armah

Dissertations

Autonomous control of mobile robots has attracted considerable attention of researchers in the areas of robotics and autonomous systems during the past decades. One of the goals in the field of mobile robotics is development of platforms that robustly operate in given, partially unknown, or unpredictable environments and offer desired services to humans. Autonomous mobile robots need to be equipped with effective, robust and/or adaptive, navigation control systems. In spite of enormous reported work on autonomous navigation control systems for mobile robots, achieving the goal above is still an open problem. Robustness and reliability of the controlled system can always …

Synchrophasor Assisted Efficient Fault Location Techniques In An Active Distribution Network, Anil Khanal

Dissertations

Reliability of an electrical system can be improved by an efficient fault location identification for the fast repair and remedial actions. This scenario changes when there are large penetrations of distributed generation (DG) which makes the distribution system an active distribution system. An efficient use of synchrophasors in the distribution network is studied with bidirectional power flow, harmonics and low angle difference consideration which are not prevalent in a transmission network. A synchrophasor estimation algorithm for the P class PMU is developed and applied to identify efficient fault location. A fault location technique using two ended synchronized measurement is derived …

A Novel Approach For Identifying Cloud Clusters Developing Into Tropical Cyclones, Chaunte' W. Lacewell

Dissertations

Providing advance notice of rare events, such as a cloud cluster (CC) developing into a tropical cyclone (TC), is of great importance. Having advance warning of such rare events possibly can help avoid or reduce the risk of damages and allow emergency responders and the affected community enough time to respond appropriately. Considering this, forecasters need better data mining and data driven techniques to identify developing CCs. Prior studies have attempted to predict the formation of TCs using numerical weather prediction models as well as satellite and radar data. However, refined observational data and forecasting techniques are not always available …

Development Of Workforce Skills: Student Perceptions Of Mentoring In First Robotics, Katie Joan Veal Wallace

Dissertations

In today’s global economy, new workforce competencies are needed for success at both individual and societal levels. The new workforce skills extend beyond basic reading, writing, and arithmetic to include higher order processes such as critical thinking and problem solving. Technical job opportunities have grown by approximately 17%, yet the United States continues to decline in science, technology, engineering and mathematics (STEM) disciplines. Further, U.S. students earn average or below average test scores when compared to other developed countries. Researchers cite the need to incorporate the learning of workplace skills into secondary education curriculum, and advocates call for new teaching …

Utilization Of Aqueous Raft Prepared Copolymers To Improve Anticancer Drug Efficacy, Andrew Christopher Holley

Dissertations

The advent of controlled radical polymerization (CRP) techniques, along with advancements in facile conjugation chemistry, now allow synthetic tailoring of precise, polymeric architectures necessary for drug/gene delivery. Reversible addition- fragmentation chain transfer (RAFT) polymerization and its aqueous counterpart (aRAFT) afford quantitative control over key synthetic parameters including block length, microstructure, and placement of structo-pendent and structo-terminal functionality for conjugation of active agents and targeting moieties. The relevance of water-soluble and amphiphilic (co)polymers synthesized by RAFT for in vitro delivery of therapeutics in biological fluids is an especially attractive feature. In many cases, polymerization, binding, conjugation, …

Fabrication, Testing And Analysis Of A Fatigue Sensor For Structural Health Monitoring, Subash Gokanakonda

Dissertations

A novel fatigue monitoring sensor (FMS) is designed, fabricated and tested for detecting and monitoring the fatigue damage and estimating the remaining life of structures and components subjected to cyclic loads. The concept is based on the characteristics of stress / strain life cycle relationship of engineering materials. Sensor consists of alternate slots and strips having different strain magnification factor with respect to the nominal strain. The sensor is designed in such a way that the strips will experience the strain which closely resemble the actual strain distribution in the notch or critical area of the component. The sensor can …

Printing Functional Electronic Circuits And Components, Ahmed Tausif Aijazi

Dissertations

The purpose of this study was to investigate the challenges in printing reliable multilayer flexible circuits, devices and components. Gravure was used as the primary printing process for this work, but due to some limitations of gravure, other printing methods were also investigated. At first a systematic study was done to determine the optimum parameters for the gravure printing of sub 50 micron lines. Commercially available silver nanoparticle inks were printed on a lab scale gravure printer, Accupress®. The highest resolution line that was electrically conductive was 36μm wide. The 9μm, 18μm and 27μm lines were printed but were not …

Lntegration Of Conventional Lithography And Printing Processes As A Key Enabling Technology For Printed And Flexible Sensing Systems, Binu Baby Narakathu

Dissertations

Sensors, which are used ubiquitously in a wide variety of applications, are revolutionizing the already ever-changing world we live in by providing real-time information about our surroundings. This dissertation focuses on the integration of conventional photolithography and printing processes as a key enabling technology for printed and flexible sensing systems.

Initially, an efficient opto-electrochemical sensing system, for the dual detection of heavy metal compounds was successfully developed. A novel microfluidic flow cell, with a reservoir volume of 25 μl, was designed and fabricated using acrylic. An electrochemical sensor with gold (Au) interdigitated electrodes (IDE) on a glass substrate was photolithographically …

A Complex Social Network Analyses Of Online Finanical Communties In Times Of Geopolitcal Military And Terrorist Events, James Usher

Dissertations

Given the advances in technology the field of social network analysis has very much hit the forefront in recent years. The information age harnesses the use of social network analysis for multiple industries and for solving complex problems. Social network analysis is an important tool in the world of the military and counter intelligence, whether it’s the capture of Osama Bin Laden or uncovering hidden Al Qaeda terrorist networks, the world around us is built on networks, be that hidden or otherwise. Online social networks give new information in the world of intelligence agencies similarly online financial communities such as …

Evaluation Of Environmental Materials As Thermal Witness Materials, Shashank Vummidi Lakshman

Dissertations

New and complex energetic materials are under development for achieving tunable pyrotechnical events for applications such as neutralization of biological weapons, bunker busters and many others. To guide the development of hybrid materials, the pyrotechnical environment they produce requires higher degree of characterization i.e. good description of spatial and temporal temperature distribution.

Temperature measurements in pyrotechnical events are especially challenging, where the temperature of the environment rises more than 2000 K on microseconds to few milliseconds time scale. These environments produce high thermal stress where traditional sensors like thermocouples, optical pyrometers struggle to describe the dynamic changes in the environment. …

Novel Scrubbing Systems For Post-Combustion Co2 Capture And Recovery, Tripura Mulukutla

Dissertations

Power plant emissions of flue gas releases considerable CO₂ to the atmosphere; CO₂ is considered to be the main contributor to global warming. Several gas absorption techniques are being investigated to reduce the capital and operating costs for CO₂ capture from post-combustion flue gas. Conventional method of CO₂ capture by an aqueous solution of monoethanolamine (MEA) and its subsequent stripping in a separate tower with steam at 120°C, is a highly energy intensive process. The low partial pressure of CO₂ in the flue gas inhibits the application of CO₂-selective membranes unless methods are …

Ignition Mechanism In Nanocomposites Thermites, Rayon Williams

Dissertations

Nanocomposite thermites (n-thermites) have been actively investigated for a wide range of potential applications including propellants, explosives, and pyrotechnics. There have been several recent efforts aimed at understanding ignition mechanisms of nanocomposite reactive materials. Although significant progress has been made, ignition mechanisms remain elusive. At the same time, a robust ignition model is required to incorporate these materials in practical energetic formulations. A challenge of this effort is to describe the mechanisms of ignition of n-thermites prepared by Arrested Reactive Milling (ARM) with different stimuli, including heat, spark and impact and also develop a multi-step kinetic model describing different processes …

Synthesis And Characterization Of Metal-Based Reactive Powders, Yasmine Aly

Dissertations

Aluminum added to propellants, explosives, and pyrotechnics, boosts their energy density. Different approaches were investigated that could shorten aluminum ignition delays, increase combustion rates, and decrease the tendency of aluminum droplets to agglomerate. Here, Al-based reactive, mechanically milled materials are prepared and characterized.

For powders with Fe, Ni, or Zn additives, the particles consist of an aluminum matrix and inclusions of Fe, Ni, or Zn comprising 10 at % of the bulk composition. For additives of Ni and Zn, only short milling times can be used to prepare composites; intermetallic phases form at longer milling times. Thermogravimetric analysis shows selective …

Improved Efficiency Organic Photovoltaic Cells Through Morphology Control And Process Modification, Qi Wu

Dissertations

Organic photovoltaic (OPV) cells have drawn great attention due to the potential to produce flexible, light weight, affordable solar cells using polymer organic photovoltaic materials; however, the current power conversion efficiency achieved for these systems is too low for widespread implementation of the technology. Morphology and phase separation are key factors determining the performance of organic photovoltaic cells. Precise control of the size and distribution of the phase-separated photoactive domains is necessary for optimum photon-electron conversion. Polyhedral oligomeric silsesquioxane (POSS) nanostructered chemicals have the potential to provide enhanced control of morphology, crystallinity, and phase dispersion in polymeric blend systems. In …

Modeling That Leads To The Prediction Of Photocatalytic Coatings Characterization, Biju Bajracharya

Dissertations

One of the abundant sources of energy on earth is a solar energy which is the clean and safest energy source. It is also known as universal energy, the most important source of renewable energy available today. On realizing that the light source has a crucial role in daily life, several scientists and researchers from centuries ago have studied to establish photo induced systems and utilized them. Long after the knowledge of thermal energy, photovoltaic energy, and photosynthesis in plants, two prominent scientists, Fujishima and Honda, have discovered the electrochemical photolysis of water with the Titanium dioxide electrode which was …

Fundamental Investigations Of Clay/Polymer Nanocomposites And Applications In Co-Extruded Microlayered Systems, Jeremy John Decker

Dissertations

The second and fourth generations of hydroxylated dendritic polyesters (HBP2, HBP4) were combined with unmodified sodium montmorillonite clay (Na+MMT) in water to generate a broad range of polymer clay nanocomposites from 0 to 100% wt/wt Na+MMT. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to investigate intercalation states of the clay galleries. It was shown that interlayer spacings were independent of generation number and changed over the composition range from 0.5 nm to 3.5 nm in 0.5 nm increments that corresponded to a flattened HBP conformation within the clay tactoids.

The HBP4/Na+MMT systems were investigated to study the …

Fluorine Containing Uv-Curable Materials For Advanced Transport Applications, James Thomas Goetz

Dissertations

The characterization of structure, thermal, gas transport, and free volume properties of two unique UV cured polymeric systems are studied and reported. In the initial pursuit of waterproof high water vapor transport membranes, it became apparent that the UV curing of fluorinated materials yielded routes to develop unique materials that fundamentally challenge conventional models for free volume and light gas transport behavior. UV-curing provides a means to rapidly “lock-in” morphologies that are accessible in the small molecule, monomer phase but rapidly become kinetically inaccessible when constraints such as covalent bonding and cross linking limit motion in the polymer system. This …

Development And Applications Of The Expanded Equivalent Fluid Method, Bharath Kumar Kandula

Dissertations

Ocean acoustics is the study of sound in the oceans. Electromagnetic waves attenuate rapidly in the water medium. Sound is the best means to transmit information underwater. Computational numerical simulations play an important role in ocean acoustics. Simulations of acoustic propagation in the oceans are challenging due to the complexities involved in the ocean environment. Different methods have been developed to simulate underwater sound propagation. The Parabolic-Equation (PE) method is the best choice in several ocean acoustic problems. In shallow water acoustic experiments, sound loses some of its energy when it interacts with the bottom. An equivalent fluid technique was …