Engineering Commons^™

Aptamer-Based Spr Biosensor For Detection Of Avian Influenza Virus, Hua Bai

Graduate Theses and Dissertations

Rapid and specific detection of avian influenza (AI) virus is urgently needed with the concerns over the outbreaks of highly pathogenic H5N1 avian influenza in animal and human infection. Aptamers are artificial oligonucleic acid that can specifically bind to target molecules. They show comparable affinity for target virus and better thermal stability than monoclonal antibodies. Those advantages make aptamers promising candidates in diagnostic and detection applications. The goal of this research was to use DNA&ndashaptamer as the specific recognition element in a portable surface plasmon resonance (SPR) biosensor for detection of AI H5N1 virus in poultry.

A SPR biosensor was …

Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas

Graduate Theses and Dissertations

Stem cell and tissue engineering offer us with a unique opportunity to research and develop new therapies for treating various diseases that are otherwise incurable using traditional medicines. However, development of these new therapies replies upon the establishment of in vitro cell culture and differentiation systems that mimic in vivo microenvironments required for cell-cell and cell-ECM interaction. The development of these cell culture systems depends upon the identification of appropriate biomaterials and cell sources. Biomaterials should be carefully selected and fabricated into scaffolds for supporting cell growth and differentiation. In this study, we explored the fabrication of 3D electrospun nanofiber …

Comparative Fatigue Analysis Of Metals And Polymers For Engineering Applications, Monica Jones

Mechanical Engineering Undergraduate Honors Theses

Rapid prototype polymers are becoming increasingly popular for engineering applications, particularly during the design phase as a quick check for size and fit; however they are not currently widely-used for load-bearing applications. Current research at the University of Arkansas Department of Mechanical Engineering focused on rapid prototyped polymers by doing cyclical tensile testing. The results were analyzed for strain energy and fatigue data. When cycling at lower percentages of ultimate stress, unusual strain energy patterns were observed. This research details testing of metals in order to compare strain energy patterns to those of the rapid prototype polymers.

Investigation Of Slopes And Deflections Of A Stepped Beam Using A Global Formula For Ey'', Raymond Salmon

Mechanical Engineering Undergraduate Honors Theses

The purpose of this paper is to investigate the slopes and deflections of a beam with two steps (i.e. a beam with a change of cross section) by use of a global formula. In order to understand the derivation and use of this formula, a brief review of singularity functions is provided. The global formula simplifies the solution method for stepped beams (eliminating the need for dividing the beam into segments and solving multiple simultaneous equations). It has been found that, when loaded on the first beam segment, the global formula allows for quick calculations of slope and deflection of …

Relative Navigation And Control Of A Hexacopter, Timothy Mclain, Randal W. Beard, Robert C. Leishman, John Macdonald

Faculty Publications

This paper discusses the progress made on developing a multi-rotor helicopter equipped with a vision-based ability to navigate through an a priori unknown, GPS-denied environment. We highlight the backbone of our system, the relative estimation and control. We depart from the common practice of using a globally referenced map, preferring instead to keep the position and yaw states in the EKF relative to the current map node. This relative navigation approach allows simple application of sensor updates, natural characterization of the transformation between map nodes, and the potential to generate a globally consistent map when desired. The EKF fuses view …

Bioengineering Approach To Understanding Tmj Pathobiology, Jonathan Kuo

All Dissertations

The temporomandibular joint (TMJ) is a load-bearing joint consisting of the condyle of the mandibular bone, the fossa eminence of the temporal bone, and a fibrocartilaginous disc held in between the bone surfaces by ligaments. The TMJ disc serves to distribute stress, lubricate movement, and protect the articular surfaces of the joint. Over ten million Americans suffer from TMJ disorders (TMD) that affect the movement and function of the joint, making everyday tasks like talking and eating difficult and painful. A wide variety of treatments and surgeries have been proposed and undertaken with limited success based on the varying degree …

Within-Subject Joint Independent Component Analysis Of Simultaneous Fmri/Erp In An Auditory Oddball Paradigm, Jain Mangalathu-Arumana, Scott A. Beardsley, E. Liebenthal

Biomedical Engineering Faculty Research and Publications

The integration of event-related potential (ERP) and functional magnetic resonance imaging (fMRI) can contribute to characterizing neural networks with high temporal and spatial resolution. This research aimed to determine the sensitivity and limitations of applying joint independent component analysis (jICA) within-subjects, for ERP and fMRI data collected simultaneously in a parametric auditory frequency oddball paradigm. In a group of 20 subjects, an increase in ERP peak amplitude ranging 1–8 μV in the time window of the P300 (350–700 ms), and a correlated increase in fMRI signal in a network of regions including the right superior temporal and supramarginal gyri, was …

Robotic Resistance Treadmill Training Improves Locomotor Function In Human Spinal Cord Injury: A Pilot Study, Ming Wu, Jill M. Landry, Brian D. Schmit, T. George Hornby, Sheng-Che Yen

Biomedical Engineering Faculty Research and Publications

Objective

To determine whether cable-driven robotic resistance treadmill training can improve locomotor function in humans with incomplete spinal cord injury (SCI).

Design

Repeated assessment of the same patients with crossover design.

Setting

Research units of rehabilitation hospitals in Chicago.

Participants

Patients with chronic incomplete SCI (N=10) were recruited to participate in this study.

Interventions

Subjects were randomly assigned to 1 of 2 groups. One group received 4 weeks of assistance training followed by 4 weeks of resistance training, while the other group received 4 weeks of resistance training followed by 4 weeks of assistance training. Locomotor training was provided by …

Effective Dielectric Constant Of Two Phase Dielectric Systems, Vladimir Petrovsky, Piotr Jasinski, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

Various theoretical approaches are implemented for electrical characterization of two-phase material systems. Most of these approaches do not include possibility of percolation of the dispersed material. In this article brick wall model is extended on the systems exhibiting percolation. Transition from brick wall geometry to corresponding equivalent circuits provides final equations for effective dielectric constant. Comparison of theoretical results with experimental data shows that developed equations provide good fitting of effective dielectric constant to experimental values. Dielectric constants of both phases and percolation threshold calculated from the fitting match the corresponding experimental values of the phases.

Phase Matching For Surface Plasmon Enhanced Second Harmonic Generation In A Gold Grating Slab, Ngoc Luong, Cheng-Wen Cheng, Min-Hsiung Shih, Wan Kuang

Electrical and Computer Engineering Faculty Publications and Presentations

Surface plasmon enhanced second harmonic generation in gold grating slabs was investigated. The efficiency is analyzed with respect to the phase matching at the fundamental and the second harmonic frequencies. A classical electromagnetic model was developed under the weak nonlinearity approximation and solved by the finite element method. The measured zeroth order transmitted second harmonic intensity was found to be in quantitative agreement with numerical results. It is shown experimentally and numerically that proper phase matching at both frequencies improves the second harmonic efficiency.

Broadband Purcell Effect: Radiative Decay Engineering With Metamaterials, Zubin Jacob, Igor I. Smolyaninov, Evgenii E. Narimanov

Birck and NCN Publications

We show that metamaterials with hyperbolic dispersion support a large number of electromagnetic states that can couple to quantum emitters leading to a broadband Purcell effect. The proposed approach of radiative decay engineering, useful for applications such as single photon sources, fluorescence imaging, biosensing, and single molecule detection, also opens up the possibility of using hyperbolic metamaterials to probe the spontaneous emission properties of atoms and artificial atoms such as quantum dots. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4710548]

Investigation Of The Electronic Properties Of The Memristor Using One Dimensional Drift Models, Swetha Gazabare

Electrical Engineering Theses

The memristor was proposed over forty years ago by Leon Chua as the missing 4th two-terminal nonlinear circuit element. Recently Hewlett-Packard (HP) announced the first fabrication of a device following memristor circuit rules. HP's device is a cross-bar resistive hysteretic switch designed for nonvolatile high density memory applications. In this thesis well-known one-dimensional drift models, which assume sinusoidal voltage sources, were used to predict level of frequency sensitivity in hysteresis curves and instantaneous power curves for memristors. Drift model simulation tests, with ac voltage sources, indicate that the memristor frequency response scales inversely with an identified time constant predicted from …

A Compressive Radar System With Chaos Based Fm Signals Generated Using The Bernoulli Map, Charan Teja Enugula

Electrical Engineering Theses

Matched filters are used in radar systems to identify echo signals embedded in noise. By using matched filters, range and Doppler information about the target can be extracted from the reflected signal. The use of matched filters in high frequency radars has the effect of increasing the cost and complexity of these systems. For that reason, the radar research community is looking at a new technique called compressive sensing or compressive sampling. This technique works by exploiting signal sparsity and has the potential to eliminate the use of matched filters and high frequency analog-to-digital converters. In this research, it is …

A Comparative Analysis Of Feature Extraction Techniques For Eeg Signals From Alzheimer Patients, Ramya Priya Mudhiganti

Electrical Engineering Theses

This research deals with the study of Alzheimer Disease (AD). Electroencephalogram (EEG) signal is a clinical tool for the diagnosis and detection of AD. EEG signals are analyzed for the diagnosis of AD applying several linear and non-linear methods of signal processing. This work studies and implements several measures of EEG signal complexity and then compares the complexity features measured or extracted from EEG signals. Time domain analysis of EEG signals is performed using several signal processing techniques such as higher order moments, entropies and fractal dimension calculation using fractal analysis. Frequency domain analysis of EEG signals is performed using …

Predictive Simulation Of Gait At Low Gravity Reveals Skipping As The Preferred Locomotion Strategy, Marko Ackermann, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The investigation of gait strategies at low gravity environments gained momentum recently as manned missions to the Moon and to Mars are reconsidered. Although reports by astronauts of the Apollo missions indicate alternative gait strategies might be favored on the Moon, computational simulations and experimental investigations have been almost exclusively limited to the study of either walking or running, the locomotion modes preferred under Earth's gravity. In order to investigate the gait strategies likely to be favored at low gravity a series of predictive, computational simulations of gait are performed using a physiological model of the musculoskeletal system, without assuming …

Power Quality And Voltage Stability Of Power Systems With A Large Share Of Distributed Energy Resources, Yuva Nandan Reddy Chejerla

Electrical Engineering Theses

The main objective of this research is to model and characterize power systems with a large share of distributed energy resources. The effect of integrating distributed energy resources such as wind farms, photovoltaic arrays, fuel cell stacks and micro-hydroelectric generators on the power quality and voltage stability of power systems is investigated and characterized. A comprehensive power system model was developed in Matlab/Simulink environment. Stand-alone and grid-connected models of distributed energy resources were developed and integrated into the system under investigation. Several characteristics such bus voltage profiles, voltage transients, power flow, and total harmonic distortion are captured and investigated. The …

Engineering Of Polyamidoamine (Pamam) Dendrimers For Gene And Drug Delivery, Quan Yuan

Theses and Dissertations

Dendrimers are a class of polymers with a highly branched, three-dimensional architecture composed of an initiator core, several interior layers of repeating units and multiple surface groups. They have been recognized as the most versatile compositionally and structurally controlled nanoscale building blocks throughout the fields of engineering, materials science, chemistry, and biology, and they have been widely investigated for drug and gene delivery. Polyamidoamine (PAMAM) dendrimers have inherent properties for gene delivery because of their high buffering capacity, polycationic surface and numerous surface groups for biofunctionlization. This dissertation is organized into four independent sections. The first section investigates a series …

Modeling Polarization And Capacitance Hysteresis Of Ferroelectric Capacitors, Bikash Shrestha

Electrical Engineering Theses

A simulation based comparative study of the polarization hysteresis of the ferroelectric capacitor using various ferroelectric models is presented. A 2-dimensional finite element device-level model was implemented using SILVACO's ATLAS device simulator to generate the polarization hysteresis characteristics for Au/Poly(vinylidene fluoride-trifluoroethylene)/Au metal-insulator-metal (MIM) device. Landau free energy expression for electric field in terms of polarization is also implemented in MATLAB to produce the polarization hysteresis curves of monocrystalline and polycrystalline ferroelectrics. The main drawback of previous models was their inability to predict polarization saturation at the same electric field limits as compared with measurements taken from a recently fabricated ferroelectric …

Development And Testing Of An Actively Adjustable Stiffness Mechanism, Eleazar Marquez, Robert Freeman, Horacio Vasquez

Mechanical Engineering Faculty Publications

This study presents the comparison of the theoretical and experimental results of the performance of an adjustable stiffness mechanism. In particular, the use of redundant actuation is emphasized in the design of a one degree-of-freedom Watt II mechanism capable of independently controlling the effective stiffness without a change in equilibrium position. This approach is in contrast to spring mechanism designs unable to actively control the spring rate independent of deflection, and with potential applications in various types of suspension and assembly systems. Results indicate that two direct drive brush-type direct current motors are required to drive the redundantly actuated mechanism …

Modeling Travel Time And Reliability On Urban Arterials For Recurrent Conditions, Prony Bonnaire Fils

USF Tampa Graduate Theses and Dissertations

Abstract

Travel time reliability is defined as the consistency or dependability in travel times during a specified period of time under stated conditions, and it can be used for evaluating the performance of traffic networks based on LOS (Level of Service) of the HCM (Highway Capacity Manual). Travel time reliability is also one of the most understood measures for road users to perceive the current traffic conditions, and help them make smart decisions on route choices, and hence avoid unnecessary delays (Liu & Ma, 2009). Therefore, travel time reliability on urban arterials has become a major concern for daily commuters, …

Innovative Desalination Systems Using Low-Grade Heat, Chennan Li

USF Tampa Graduate Theses and Dissertations

Water and energy crises have forced researchers to seek alternative water and energy sources. Seawater desalination can contribute towards meeting the increasing demand for fresh water using alternative energy sources like low-grade heat. Industrial waste heat, geothermal, solar thermal, could help to ease the energy crisis.

Unfortunately, the efficiency of the conventional power cycle becomes

uneconomically low with low-grade heat sources, while, at the same time, seawater desalination requires more energy than a conventional water treatment process. However, heat discarded from low-grade heat power cycles could be used as part of desalination energy sources with seawater being used as coolant …

The Application Of Origami To The Design Of Lamina Emergent Mechanisms (Lems) With Extensions To Collapsible, Compliant And Flat-Folding Mechanisms, Holly Greenberg

Theses and Dissertations

Lamina emergent mechanisms (LEMs) are a subset of compliant mechanisms which are fabricated from planar materials; use compliance, or flexibility of the material, to transfer energy; and have motion that emerges out of the fabrication plane. LEMs provide potential design advantages by reducing the number of parts, reducing cost, reducing weight, improving recyclability, increasing precision, and eliminating assembly, to name a few. However, there are inherent design and modeling challenges including complexities in large, non-linear deflections, singularities that exist when leaving the planar state, and the coupling of material properties and geometry in predicting mechanism behavior. This thesis examines the …

Mesh Adaption For Efficient Multiscale Implementation Of One-Dimensional Turbulence, D. O. Lignell, A. R. Kerstein, G. Sun, E. I. Monson

Faculty Publications

One-Dimensional Turbulence (ODT) is a stochastic model for turbulent flow simulation. In an atmospheric context, it is analogous to single-column modeling (SCM) in that it lives on a 1D spatial domain, but different in that it time advances individual flow realizations rather than ensemble-averaged quantities. The lack of averaging enables a physically sound multiscale treatment, which is useful for resolving sporadic localized phenomena, as seen in stably stratified regimes, and sharp interfaces, as observed where a convective layer encounters a stable overlying zone. In such flows, the relevant scale range is so large that it is beneficial to enhance model …

Electrochemical Preparation Of Nanostructural Pt-Ni And Pd-Ni Films For Ethanol Electro-Oxidation, Chen-Zhong Yao, Hui-Xuan Ma, Bo-Hui Wei

Journal of Electrochemistry

The Pt-Ni and Pd-Ni films were successfully prepared on Ti substrates by electrodeposition method. The porous Pt-Ni nanoflakes appeared to be uniform with the thickness of the slices about 10 ~ 20 nm. The porous Pd-Ni nanoparticles with a flower shape appeared to be uniform with the diameters of 50 ~ 60 nm. The XRD patterns also indicated that the Pd-Ni and Pt-Ni nanostructures have the poor crystallinity. The onset potentials of ethanol oxidation were negatively shifted to –0.74 V on Pt-Ni electrodes and –0.71 V on Pd-Ni electrodes, respectively. Addition of Ni could enhance catalytic activities and antitoxic properties …

Synthesis Of Lini0.5Co0.2Mn0.3O2 For Lithium Ion Batteries And The Mechanism Of Capacity Fading At High Temperature, Wen Liu, Miao Wang, Ji-Tao Chen, Xin-Xiang Zhang, Heng-Hui Zhou

Journal of Electrochemistry

The Ni-rich cathode materials, LiNi_0.5Co_0.2Mn_0.3O₂, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh·g^-1 in the 3.0~4.4 V at 0.2C. However, at 55 °C the LiNi_0.5Co_0.2Mn_0.3O₂ experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi_0.5Co_0.2Mn_0.3O₂ cycled at high temperature in range of high-voltage charge and …

Electrochemical Performances Of Carbon-Coated Na2Ti6O13 Nanotubes, Guo-Ran Li, Shuai Sun, Xue-Ping Gao

Journal of Electrochemistry

With rutile TiO₂ and NaOH as starting materials, the Na₂Ti₆O₁₃ nanotubes were prepared by a hydrothermal reaction. The carbon-coated Na₂Ti₆O₁₃ nanotubes were obtained by treating the Na₂Ti₆O₁₃ nanotubes for 4 h in glucose aqueous solutions containing 0.1 mol·L^-1 NaOH. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microcopy (TEM). The results showed that the dimensions of carbon-coated Na₂Ti₆O₁₃ nanotubes were 14 ~ 19 nm of outer diameter, 2 ~ 5 …

Synthesis And Electrochemical Properties Of Yttrium-Doped Lini0.49Mn1.49Y0.02O4, Xian-Wen Zhang, Zheng-Xi Zhang, Li Yang, Shao-Hua Fang, Long Qu

Journal of Electrochemistry

The LiNi_0.49Mn_1.49Y_0.02O₄ cathode material was synthesized using the citric acid-assisted sol-gel method by partial substitutions of Ni and Mn with Y in the LiNi_0.5Mn_1.5O₄ material. The influences of Y doping on the structure and electrochemical properties were investigated by means of X-ray diffraction, cyclic voltammetry, galvanostatic charge/discharge tests and AC impedance spectroscopy. The results showed that the introduction of Y into the LiNi_0.5Mn_1.5O₄ greatly improved the cycle performance and rate capability. When the charge and discharge current was 1 C in the potential …

Template-Free Synthesis Of Porous Nio Hierarchical Structure For High Performance Supercapacitors, Yun Huang, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

A facile and template-free hydrothermal method is proposed to successfully synthesize porous NiO hierarchical structure, which is found to be assembled from ultrathin NiO nanosheets. As for electrochemical pseudocapacitor application, the obtained material exhibits not only high specific capacitances of 435 F·g^-1 at 20 mV·s^-1 and 367 F·g^-1 at 10 A·g^-1, but also holds a good electrochemical stability over 1000 cycles at a current rate of 20 mV·s^-1. These results suggest that the hierarchical structured porous NiO is a promising supercapacitor electrode material.

Electrochemical Reduction Of Co2 On Sn/Cu Electrodes, Chen-Chen Zhao, Jian-Wei Guo, Li Wang, Xiang-Ming He, Cheng Wang, Zhi-Xiang Liu

Journal of Electrochemistry

The Sn/Cu electrodes were prepared by electroplating method and their morphologies under different galvanization current densities were determined by SEM. In alkali, the effects of Sn/Cu electrodes on the activities towards hydrogen evolution and electrochemical reduction of CO₂ were investigated in alkaline solutions using a three-electrode system. These results indicated that the Sn/Cu electrodes prepared at 10 mA/cm² and 15 mA/cm² showed good activities, while that prepared at 15 mA/cm² was even better in activities. The synergetic structure of the Sn/Cu electrode to be beneficial to electrochemical reduction of CO₂ has been pointed out.

Electrochemical Properties Of The Keggin-Type Lacunary Heteropolysilicate Anion And Its Eectrocatalysis For H2O2 Reduction, Xi-Long Liu, Chun-Yan Wu, Fang Zhou, Hong-Sheng Liu, Ying-Jie Hua, Chong-Tai Wang, Xiao-Yang Liu

Journal of Electrochemistry

Electrochemical properties of the Keggin-type lacunary heteropolysilicate anion SiW₁₁O₃₉^8- (SiW₁₁) and its indirect electrocatalysis for H₂O₂ reduction in the supporting electrolyte containing 0.1 mol·L^-1 NaHSO₄ and Na₂SO₄ solutions were investigated using cyclic voltammetry, square wave voltammetry and alternating current impedance spectroscopy. Experimental results indicated that SiW₁₁ showed two pairs of reversible redox waves on the glassy carbon (GC) electrode in an acidic solution. The electron transfer number corresponding to the two pairs of waves was one, and the proton transfer number involved was two during …