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Brain Electrophysiology In The Presence Of Acoustic Stimuli, Kristen Howorka

McKelvey School of Engineering Theses & Dissertations

Neuroscience is the study of the structure and function of the brain. This is inclusive of neurochemistry, physiology, anatomy, molecular biology, computer science, engineering and many adjacent disciplines. While there have been a multitude of studies in this field, there are still so many questions left unanswered about the brain. One such question pertains to how animals and humans perceive stimuli from the environmental periphery, a neuroscience sub-area known as sensory processing.

By design, humans have neurological states and receptors which organically take in all of these stimuli and decipher them for everyday needs. Sensory input enables subjects to perform …

Quantification And Reconstruction In Photoacoustic Tomography, Zijian Guo

All Theses and Dissertations (ETDs)

Optical absorption is closely associated with many physiological important parameters, such as the concentration and oxygen saturation of hemoglobin. Conventionally, accurate quantification in PAT requires knowledge of the optical fluence attenuation, acoustic pressure attenuation, and detection bandwidth. We circumvent this requirement by quantifying the optical absorption coefficients from the acoustic spectra of PA signals acquired at multiple optical wavelengths. We demonstrate the method using the optical-resolution photoacoustic microscopy: OR-PAM) and the acoustical-resolution photoacoustic microscopy: AR-PAM) in the optical ballistic regime and in the optical diffusive regime, respectively. The data acquisition speed in photoacoustic computed tomography: PACT) is limited by the …

Design, Construction And Testing Of A High Temperature High Pressure Spectroscopic Cell For Polymer Physics Studies, Sai Janani Ganesan

All Theses and Dissertations (ETDs)

Knowledge of phase behaviour of polymer solutions is critical in understanding their chemical and physical properties. Proteins are polymers and aggregation is a phase separation process, hence there is a need for the use of techniques from polymer physics to characterize phase diagrams. Prior work on protein aggregation indicates the need for superheated water to disaggregate the system, accordingly this report proposes a simple, efficient, and reliable instrument for experimentally determining cloud-point curves for binary polymer-solvent systems. Cloud-point measurements are a prominent technique in constructing phase diagrams. A one milliliter optical cell has been designed and constructed, to withstand 200 …

Aerosol Route Synthesis And Applications Of Doped Nanostructured Materials, Manoranjan Sahu

All Theses and Dissertations (ETDs)

Nanotechnology presents an attractive opportunity to address various challenges in air and water purification, energy, and other environment issues. Thus, the development of new nanoscale materials in low-cost scalable synthesis processes is important. Furthermore, the ability to independently manipulate the material properties as well as characterize the material at different steps along the synthesis route will aide in product optimization. In addition, to ensure safe and sustainable development of nanotechnology applications, potential impacts need to be evaluated. In this study, nanomaterial synthesis in a single-step gas phase reactor to continuously produce doped metal oxides was demonstrated. Copper-doped TiO2 nanomaterial properties: …

Mixed-Mode Control Interfaces Of Mobile Robot Teams, Erik Karulf

All Theses and Dissertations (ETDs)

We propose applying various techniques and ideas, from video games, to the design of a task-level control interface for teams of mobile robots. The control interface, which visually resembles a video game and contains the functional elements of traditional robot control software, was designed and implemented using the ROS software framework. Unlike previous interfaces in the literature, our interface allows the user to control more than one robot and supports "sliding autonomy." This application allows the user to assign differing levels of independence to the robots dynamically, dependent on the situation. We present an overview of the implemented system, a …

Hidden Markov Models For Heart Rate Variability With Biometric Applications, Michael Walker Ii

All Theses and Dissertations (ETDs)

The utility of hidden Markov models: HMM) for modeling individual heart rate variability: HRV) is presented. Starting with a physiologically based statistical model for HRV from the literature, we justify use of HMMs and present methods for parameterizing the model. The forward-backward algorithm and expectation-maximization algorithm are used to estimate the model and the hidden states for a given observation sequence of inter-beat intervals. Multiple initialization techniques are presented to avoid local maxima. Model order is determined from the data sequence using the Bayesian information criterion. Models are trained on twelve hour recordings. The models are then used to discriminate …

Hydrodynamics Of Trickle Bed Reactors: Measurements And Modeling, Zeljko Kuzeljevic

All Theses and Dissertations (ETDs)

In this study we develop the computational and experimental tools to assist us in performance evaluation of trickle bed reactors: TBRs). The study focuses on experimental characterization of the flow distribution, and development of computational fluid dynamics: CFD) model of trickle flow. The experimental study has been performed to examine the quality of liquid phase distribution in a high pressure system. The results were provided in terms of distribution of the effluent liquid fluxes and cross-sectional liquid holdups. Their individual trends, but also their relation with respect to operating conditions was examined. Characterization of bed porosity distribution has been performed …

Modeling And Detection Of Uterine Contractions Using Magnetomyography, Patricio La Rosa

All Theses and Dissertations (ETDs)

In this dissertation, we develop a novel mathematical framework for modeling and analyzing uterine contractions using biomagnetic measurements. The study of myometrium contractility during pregnancy is relevant to the field of reproductive assessment. Its clinical importance is grounded in the need for a better understanding of the bioreproduction mechanisms. For example, in the last decade the number of preterm labors has increased significantly. Preterm birth can cause health problems or even be fatal for the fetus if it happens too early, and, at the same time, it imposes significant financial burdens on health care systems. Therefore, it is critical to …

An Algorithm And Methodology For Static Response Based Damage Detection In Structural Systems, Augusto Terlaje

All Theses and Dissertations (ETDs)

A damage detection algorithm and procedure is presented in this dissertation that utilizes static response data and Optimality Criterion optimization. Static displacement measurements are used as constraints in the damage detection algorithm that identifies potential areas of damage in structural systems. The research aims to improve upon the master's level research performed by the author. First, the robustness of the algorithm is improved by use of a least squares approximation for determining the Lagrange multipliers that are necessary for optimization. Second, an active parameter selection subroutine is used to improve the accuracy of damage detection in the presence of experimental …

The Role Of Flue-Gas Recycle In Submicrometer Particle Formation During Oxy-Combustion Of American And Chinese Coals, Selegha Daukoru

All Theses and Dissertations (ETDs)

No abstract provided.

An Airloads Theory For Morphing Airfoils In Dynamic Stall With Experimental Correlation, Loren Ahaus

All Theses and Dissertations (ETDs)

Helicopter rotor blades frequently encounter dynamic stall during normal flight conditions, limiting the applicability of classical thin-airfoil theory at large angles of attack. Also, it is evident that because of the largely different conditions on the advancing and retreating sides of the rotor, future rotorcraft may incorporate dynamically morphing airfoils: trailing-edge flaps, dynamic camber, dynamic droop, etc.). Reduced-order aerodynamic models are needed for preliminary design and flight simulation. A unified model for predicting the airloads on a morphing airfoil in dynamic stall is presented, consisting of three components. First, a linear airloads theory allows for arbitrary airfoil deformations consistent with …

Front End Specifications And The Propagation Of Construction Claims, Sidney Hymes

All Theses and Dissertations (ETDs)

Front End Specifications represent the administrative, organizational, performance and payment requirements for construction projects. The vast majority of construction contracts use Front End Specifications, either from an independent source or prepared in-house. In spite of the crucial role of Front End Specifications, little is known regarding whether Front End Specifications increase or decrease claims in construction. Further, no published reports to date have investigated whether construction claims are systematically related to Front End Specification complexity, partnering, business size or document authorship. In the present quantitative study, participants: n = 150) from the construction industry, including contractors, subcontractors, designers and owners, …

Dual-Modality Thermoacoustic And Photoacoustic Imaging, Manojit Pramanik

All Theses and Dissertations (ETDs)

Diagnosis of early breast cancer is the key to survival. The combined contrasts from thermoacoustic and photoacoustic tomography: TAT and PAT) can potentially predict early stage breast cancer. We have designed and engineered a breast imaging system integrating both thermoacoustic and photoacoustic imaging techniques to achieve dual-contrast: microwave and light absorption), non-ionizing, low-cost, high-resolution, three-dimensional breast imaging. We have also developed a novel concept of using a negative acoustic lens to increase the acceptance angle of an unfocused large-area ultrasonic transducer: detector), leading to more than twofold improvement of the tangential resolution in both TAT and PAT when the object …

Geochemical Conditions Affecting Uranium(Vi) Fate And Transport In Soil And Groundwater In The Presence Of Phosphate, Abhas Singh

All Theses and Dissertations (ETDs)

Soil and groundwater contamination with actinides like uranium is a serious environmental concern. Phosphate addition to uranium-contaminated soil and groundwater can potentially provide long-term in-situ U(VI) immobilization by precipitation of low solubility U(VI)-phosphates. Reactions at the iron: oxy)hydroxide-water interface can control macroscopic transport and long-term stability of uranium. First, the interactions among phosphate, U(VI), and goethite: alpha-FeOOH) were investigated in a year-long batch experimental study. Dissolved U(VI) and phosphate concentrations were interpreted within a reaction-based modeling framework. U(VI) uptake mechanism varied with the aqueous composition. For most initially supersaturated conditions, chernikovite, H3O(UO2)(PO4)*3H2O(s), nucleated homogeneously, but heterogeneous nucleation probably occurred in …

Piezoelectric Control Of Structures Prone To Instabilities, Sunjung Kim

All Theses and Dissertations (ETDs)

Thin-walled structures such as stiffened panels fabricated out of high strength materials are ubiquitous in aerospace structures. These are prone to buckle in a variety of modes with strong possibility of adverse interaction under axial compression and/or bending. Optimally designed stiffened panels, at an appropriate combination of axial compression and suddenly applied lateral pressure undergo large amplitude oscillations and may experience divergence. Under aerodynamic loading, they can experience flutter instability with the amplitudes of oscillations attaining a limit: LCO) or escalating without any limit. Control of structures prone to these forms of instability using piezo-electric actuators is the theme of …

The Effect Of Equal Channel Angular Extrusion (Ecae) And Boron Additions On The Mechanical Properties Of A Biomedical Ti-Nb-Zr-Ta (Tnzt) Alloy, Gian Colombo

All Theses and Dissertations (ETDs)

New metastable-beta type titanium alloys based on the biocompatible elements Ti-Nb-Zr-Ta: TNZT) have been developed to address the shortcomings: e.g. incomplete biocompatibility, high modulus, etc.) of the traditionally used materials in joint replacement prostheses. Equal channel angular extrusion: ECAE) processing has the capability to improve the mechanical properties of these alloys to broaden their potential biomedical applications. The focus of this investigation is to evaluate and optimize the ECAE process to produce maximum property improvement, and explore the effectiveness of boron as a grain refining agent. Deformation mechanisms are identified for various processing conditions, and the strain distribution induced during …

Ionic Mechanisms Of Action Potential Rate Dependence, Conduction And Block In Normal Epicardium And In Remodeled Epicardium Post-Infarction, Keith Decker

All Theses and Dissertations (ETDs)

In this work, detailed computational models are used to study the electrophysiology of normal epicardium and the arrhythmogenic effects of epicardial cell remodeling post-infarction. The canine epicardial myocyte model described here reproduces a wide range of experimentally observed rate dependent phenomena in cell and tissue. Model behavior depends on updated formulations for the 4-AP sensitive transient outward current: Ito1), the slow component of the delayed rectifier potassium current: IKs), the L-type Ca2+ channel: ICa,L) and the sodium-potassium pump: INaK) fit to data from canine ventricular myocytes. The model shows that Ito1 plays a limited role in potentiating peak ICa,L and …

Drilling Induced Fatigue Damage In Ti-6al-4v, James Castle

All Theses and Dissertations (ETDs)

The objective of this work is to develop an understanding of the relationship between hole drilling processes and the fatigue performance of the resulting part in Ti-6Al-4V. This problem is significant, as on the order of one-hundred thousand to a million holes are created in a typical large aircraft, and the limiting performance criterion is usually the fatigue lifetime. The path between the drilling process parameters and the fatigue performance has two main steps: characterization of the thermo-mechanical drill process and assessment of the relationship between the hole integrity left by the drill process and the fatigue performance. Development has …

Magnetic Resonance Imaging And Surface-Based Analysis Techniques To Quantify Growth Of The Developing Brain, Andrew Knutsen

All Theses and Dissertations (ETDs)

Human brains, and those of most higher mammals, are gyrencephalic: folded) to accommodate a large cortical surface within the limited volume of the skull. Abnormal folding of the cerebral cortex in humans is associated with a number of neurological dysfunctions and diseases such as schizophrenia and Williams syndrome. To understand the mechanism of gyrification, and to illuminate the underlying causes of abnormal folding, objective, quantitative methods to characterize normal and abnormal development must be developed. The ferret is an excellent model in which to study the development of convolutions in the brain because folding occurs post-natally over a period of …

Electrical And Magnetic Separation Of Particles, Lin Li

All Theses and Dissertations (ETDs)

Particle separation technologies have been utilized in many industrial fields, such as pigment and filler production, mineral processing, environmental protection, the food and beverage industry, and the chemical industry, as well as in biomedical application, such as cell biology, molecular genetics, biotechnological production, clinical diagnostics, and therapeutics. A lot of particle separation technologies using various mechanics in terms of the differences in the physical or physico-chemical properties of the particles have been developed. Among these categories, electrical and magnetic separations are of great interest in recent researches. The overall objective of this dissertation is to advance our current knowledge on …

Modeling Aerial Refueling Operations, Allen Mccoy

All Theses and Dissertations (ETDs)

Aerial Refueling: AR) is the act of offloading fuel from one aircraft: the tanker) to another aircraft: the receiver) in mid flight. Meetings between tanker and receiver aircraft are referred to as AR events and are scheduled to: escort one or more receivers across a large body of water; refuel one or more receivers; or train receiver pilots, tanker pilots, and boom operators. In order to efficiently execute the Aerial Refueling Mission, the Air Mobility Command: AMC) of the United States Air Force: USAF) depends on computer models to help it make tanker basing decisions, plan tanker sorties, schedule aircraft, …

Electrospray Methodologies For Characterization And Deposition Of Nanoparticles, Luis Balam Modesto Lopez

All Theses and Dissertations (ETDs)

Electrospray is an aerosolization method that generates highly charged droplets from solutions or suspensions and, after a series of solvent evaporation - droplet fission cycles, it results in particles carrying multiple charges. Highly charged particles are used in a variety of applications, including particle characterization, thin film deposition, nanopatterning, and inhalation studies among several others. In this work, a soft X-ray photoionization was coupled with an electrospray to obtain monodisperse, singly charged nanoparticles for applications in online size characterization with electrical mobility analysis. Photoionization with the soft X-ray charger enhanced the diffusion neutralization rate of the highly charged bacteriophages, proteins, …

Adaptive Ofdm Radar For Target Detection And Tracking, Satyabrata Sen

All Theses and Dissertations (ETDs)

We develop algorithms to detect and track targets by employing a wideband orthogonal frequency division multiplexing: OFDM) radar signal. The frequency diversity of the OFDM signal improves the sensing performance since the scattering centers of a target resonate variably at different frequencies. In addition, being a wideband signal, OFDM improves the range resolution and provides spectral efficiency. We first design the spectrum of the OFDM signal to improve the radar's wideband ambiguity function. Our designed waveform enhances the range resolution and motivates us to use adaptive OFDM waveform in specific problems, such as the detection and tracking of targets. We …

Statistical Design And Imaging Of Position-Encoded 3d Microarrays, Pinaki Sarder

All Theses and Dissertations (ETDs)

We propose a three-dimensional microarray device with microspheres having controllable positions for error-free target identification. Here targets: such as mRNAs, proteins, antibodies, and cells) are captured by the microspheres on one side, and are tagged by nanospheres embedded with quantum-dots: QDs) on the other. We use the lights emitted by these QDs to quantify the target concentrations. The imaging is performed using a fluorescence microscope and a sensor. We conduct a statistical design analysis to select the optimal distance between the microspheres as well as the optimal temperature. Our design simplifies the imaging and ensures a desired statistical performance for …

Fluid Dynamics And Scale-Up Of Bubble Columns With Internals, Ahmed Youssef

All Theses and Dissertations (ETDs)

Bubble columns and slurry bubble columns, as multiphase reactors, are favored for a wide range of applications in the chemical, biochemical, petrochemical and metallurgical industries. They are considered the reactor of choice for the Fischer Tropsch synthesis, among other applications, offering an alternative energy source and providing clean liquid fuels as compared to other reactors. Most of the industrial applications of bubble column reactors require the utilization of heat exchanging tubes, the effect of which on the reactor's performance is not fully understood. This study proposes detailed investigations of selected local hydrodynamics in bubble columns with and without internal heat …

Dissolution, Formation, And Transformation Of The Lead Corrosion Product Pbo2: Rates And Mechanisms Of Reactions That Control Lead Release In Drinking Water Distribution Systems, Yanjiao Xie

All Theses and Dissertations (ETDs)

As one of the major lead corrosion products in lead service lines, lead(IV) oxide: PbO₂) can react with water through reductive dissolution, resulting in elevated lead concentrations in tap water. Limited data are available on the rates and mechanisms of PbO₂ dissolution. Information regarding the impact of water chemistry on the rates and mechanisms of PbO₂ dissolution can provide potential strategies to control the release of lead from corrosion products to drinking water. The present study investigated effects of water chemistry on the rates and mechanisms of PbO₂ dissolution, the equilibrium solubility of PbO_{2 …}

Two-Direction Cracking Shear-Friction Membrane Model For Finite Elment Analysis Of Reinforced Concrete, Jeffrey Mitchell

All Theses and Dissertations (ETDs)

There are a multitude of existing material models for the finite element analysis of cracked reinforced concrete that provide reduced shear stiffness but do not limit shear strength. In addition typical models are not based on the actual physical behavior of shear transfer across cracks by shear friction recognized in the ACI Building Code and present in previous experimental work. Recently a shear friction model was proposed that was able to capture the recognized cracked concrete behavior by limiting the shear strength as a function of yielding in the reinforcement across the crack. However, the proposed model was only formulated …

Integration Of Multi-Sensory Earth Observations For Characterization Of Air Quality Events, Erin Robinson

All Theses and Dissertations (ETDs)

In order to characterize air quality events, such as dust storms or smoke events from fires, a wide variety of Earth observations are needed from satellites, surface monitors and models. Traditionally, the burden of data access and processing was placed on the data user. These challenges of finding, accessing and merging data are overcome through the principles of Service Oriented Architecture. This thesis describes the collaborative, service-oriented approach now available for air quality event analysis, where datasets are turned into services that can be accessed by tools through standard queries. This thesis extends AQ event evidence to include photos, videos …

Characterization Of Scannable Leaky Wave Antennas Using An Extended Metamaterial Framework, Garrett Gilchrist

All Theses and Dissertations (ETDs)

No abstract provided.

Engineering The Optical Properties Of Gold Nanostructures For Biomedical Applications, Leslie Au

All Theses and Dissertations (ETDs)

This research investigated the synthesis and optical properties of Au nanostructures with an aim to use them as imaging agents and photothermal transducers for the diagnosis and treatment of cancer. I have produced Au nanocages with hollow interiors and porous walls using the galvanic replacement reaction between Ag nanocubes and AuCl₄-. I have engineered these Au nanocages to have localized surface plasmon resonance: LSPR) peaks in the near-infrared region with strong absorption. These optical properties allow for the imaging of biological tissues at deeper penetration and the photoablation of cancer. By replacing AuCl₄- with AuCl_{2 …}