Nanoscience and Nanotechnology Commons^™

Silica Nanoparticle-Based Coatings With Superhydrophilic And Superhydrophobic Properties, Robert Andrew Fleming

Graduate Theses and Dissertations

Superhydrophilic and superhydrophobic surfaces have potential for implementation into a variety of fields, including self-cleaning surfaces, anti-fogging transparent materials, and biomedical applications. In this study, sandblasting, oxygen plasma treatments, silica nanoparticle films, and a low surface energy fluorocarbon film were employed to change the natural surface wettability of titanium, glass, and polyethylene terephthalate (PET) substrates, with an aim to produce superhydrophilic and superhydrophobic behavior. The effects of these surface modifications are characterized by water contact angles (WCAs), surface wetting stability, surface morphology and roughness, surface elemental composition, and optical transmittance measurements. The results show that stable superhydrophilic and superhydrophobic surfaces …

Distribution Map Of Multi-Walled Carbon Nanotubes In A Refrigerant/Oil Mixture Within A 2.5 Ton Unitary Air-Conditioner, Warren Russell Long

Graduate Theses and Dissertations

In recent years, nanoparticles have received considerable attention as a potential additive to heat transfer fluids (i.e. refrigerant) in order to increase the heat transfer capabilities of these fluids. The potential of carbon nanotubes (CNTs) to exit the compressor, migrate throughout a vapor compression air conditioning system, and possibly foul the components of such a system was experimentally investigated in this research. Six grams of CNTs were dispersed in the polyol ester oil used by a 2.5 ton (8.79 kW) unitary air conditioning system, which was continuously operated for 168 hours. After this time, the unit was shut down and …

Energy Trapping Of Thickness-Shear And Thickness-Twist Modes In A Partially Electroded At-Cut Quartz Resonator, Huijing He, Guoquan Nie, Jinxi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

The thickness-shear and thickness-twist vibrations of a finite and partially electroded AT-cut quartz resonator are investigated. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56 . An analytical solution is obtained using Fourier series from which the free vibration resonant frequencies, mode shapes, and energy trapping are calculated and examined.

Design, Fabrication, Testing Of Cnt Based Isfet And Characterization Of Nano/Bio Materials Using Afm, Zhuxin Dong

Graduate Theses and Dissertations

A combination of Carbon Nanotubes (CNTs) and Ion Selective Field Effect Transistor (ISFET) is designed and experimentally verified in order to develop the next generation ion concentration sensing system. Micro Electro-Mechanical System (MEMS) fabrication techniques, such as photolithography, diffusion, evaporation, lift-off, packaging, etc., are required in the fabrication of the CNT-ISFET structure on p-type silicon wafers. In addition, Atomic Force Microscopy (AFM) based surface nanomachining is investigated and used for creating nanochannels on silicon surfaces. Since AFM based nanomanipulation and nanomachining is highly controllable, nanochannels are precisely scratched in the area between the source and drain of the FET where …

Maximal Force Characteristics Of The Ca2+-Powered Actuator Of Vorticella Convallaria, Sangjin Ryu, Matthew J. Lang, Paul Matsudaira

Department of Mechanical and Materials Engineering: Faculty Publications

The millisecond stalk contraction of the sessile ciliate Vorticella convallaria is powered by energy from Ca²⁺ binding to generate contractile forces of ~10 nN. Its contractile organelle, the spasmoneme, generates higher contractile force under increased stall resistances. By applying viscous drag force to contracting V. convallaria in a microfluidic channel, we observed that the mechanical force and work of the spasmoneme depended on the stalk length, i.e., the maximum tension (150–350 nN) and work linearly depended on the stalk length (~2.5 nN and ~30 fJ per 1 mm of the stalk). This stalk-length dependency suggests that motor units of …

Characterization Of Conducting-Polymer-Based Bimorph Vibration Sensors, Weihua Li, Geoffrey M. Spinks, Lianbin Zhao, Yanzhe Wu, Dezhi Zhou, G G. Wallace

Professor Weihua Li

This paper presents theoretical and experimental investigation of mechanical-electrical properties of conducting polymers based bimorph sensors. A material parameter, hCP , is proposed to represent linear relationship between induction charge and the applied external deformation. Based on this assumption, a constitutive equation for bimorph sensors under steady-state external loadings are constructed and then solved. Mechanical-electrical properties of bimorph sensors are experimentally studied using both vibration-amplitude sweep mode and frequency sweep mode. The material parameter hCP , is identified by comparing theoretical analysis and experimental results. The applications of conducting polymers based bimorph sensors in smart structures are also discussed.

Shear-Horizontal Vibration Modes Of An Oblate Elliptical Cylinder And Energy Trapping In Contoured Acoustic Wave Resonators, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

We study shear-horizontal free vibrations of an elastic cylinder with an oblate elliptical cross section and a traction-free surface. Exact vibration modes and frequencies are obtained. The results show the existence of thickness-shear and thickness-twist modes. The energy-trapping behavior of these modes is examined. Trapped modes are found wherein the vibration energy is largely confined to the central portion of the cross section and little vibration energy is found at the edges. It is also shown that face-shear modes are not allowed in such a cylinder. The results are useful for the understanding of the energy trapping phenomenon in contoured …

Nonlinear Mechanical Behavior Of The Human Common, External And Internal Carotid Arteries In Vivo, Alexey Kamenskiy, Yuris A. Dzenis, Jason N. Mactaggart, Thomas G. Lynch, Syed A. Jaffar Kazmi, Iraklis I. Pipinos

Department of Mechanical and Materials Engineering: Faculty Publications

Introduction—The mechanical environment and properties of the carotid artery play an important role in the formation and progression of atherosclerosis in the carotid bifurcation. The purpose of this work was to measure and compare the range and variation of circumferential stress and tangent elastic moduli in the human common (CCA), external (ECA) and internal (ICA) carotid arteries over the cardiac cycle in vivo.

Methods—Measurements were performed in the surgically exposed proximal cervical CCA, distal ECA and distal ICA of normotensive patients (n = 16) undergoing carotid endarterectomy. All measurements were completed in vivo over the cardiac cycle …

Three-Dimensional Geometry Of The Human Carotid Artery, Alexey Kamenskiy, Jason N. Mactaggart, Iraklis I. Pipinos, Jai Bikhchandani, Yuris A. Dzenis

Department of Mechanical and Materials Engineering: Faculty Publications

Accurate characterization of carotid artery geometry is vital to our understanding of the pathogenesis of atherosclerosis. Three-dimensional computer reconstructions based on medical imaging are now ubiquitous; however, mean carotid artery geometry has not yet been comprehensively characterized. The goal of this work was to build and study such geometry based on data from 16 male patients with severe carotid artery disease. Results of computerized tomography angiography were used to analyze the cross-sectional images implementing a semiautomated segmentation algorithm. Extracted data were used to reconstruct the mean three-dimensional geometry and to determine average values and variability of bifurcation and planarity angles, …

Electrohydrodynamic Enhancement Of Heat Transfer And Mass Transport In Gaseous Media, Bulk Dielectric Liquids And Dielectric Thin Liquid Films, Seyed Reza Mahmoudi

Electronic Thesis and Dissertation Repository

Controlling transport phenomena in liquid and gaseous media through electrostatic forces has brought new important scientific and industrial applications. Although numerous EHD applications have been explored and extensively studied so far, the fast-growing technologies, mainly in the semiconductor industry, introduce new challenges and demands. These challenges require enhancement of heat transfer and mass transport in small scales (sometimes in molecular scales) to remove highly concentrated heat fluxes from reduced size devices. Electric field induced flows, or electrohydrodynamics (EHD), have shown promise in both macro and micro-scale devices.

Several existing problems in EHD heat transfer enhancements were investigated in this thesis. …

Rehabilitation And Exercise Machine, Judith M. Burnfield, Yu Shu, Thad W. Buster, Carl Nelson

Department of Mechanical and Materials Engineering: Faculty Publications

An improved rehabilitation and exercise machine is provided which allows a person with physical limitations, disabilities or chronic conditions to use the machine in order to rehabilitate their muscles, improve joint flexibility, and enhance cardiovascular fitness.

Model-Based Systems And Methods For Analyzing And Predicting Outcomes Of Vascular Interventions And Reconstructions, Yuris A. Dzenis, Alexey Kamenskiy, Iraklis I. Pipinos, Jason N. Mactaggart

Department of Mechanical and Materials Engineering: Faculty Publications

Systems and methods for analyzing and predicting treatment outcomes of medical procedures such as vascular interventions and reconstructions are disclosed. An illustrative system for analyzing and predicting therapeutic outcomes of medical procedures comprises a relational database configured for classifying and storing patient specific input data for multiple patients, a fluid-solid interaction biomechanical model configured for performing a biomechanics simulation and generating biomechanics data, and a graphical user interface.

Metal Oxide Graphene Nanocomposites For Organic And Heavy Metal Remediation, Tanvir E. Alam

USF Tampa Graduate Theses and Dissertations

This thesis consists of two research problems in the water decontamination area. In the first work, the main focus is to understand the structure and photocatalytic activity of titanium dioxide with graphene (G-TiO2) which is synthesized by using sol-gel method. The photocatalytic activity of TiO2 is limited by the short electron hole pair recombination time. Graphene, with high specific surface area and unique electronic properties, can be used as a good support for TiO2 to enhance the photocatalytic activity. The obtained G-TiO2 photocatalysts has been characterized by X-Ray Diffraction (XRD), Raman Spectroscopy, Transmission Electron Microscopy (TEM), FTIR Spectroscopy and Ultraviolet …

Effects Of Mismatched Electrodes On An At-Cut Quartz Resonator, Huijing He, Jinxi Liu, Jiashi Yang

Department of Mechanical and Materials Engineering: Faculty Publications

We study thickness-shear and thickness-twist free vibrations of a finite AT-cut quartz resonator with mismatched electrodes. The equations of anisotropic elasticity are used with the omission of the small elastic constant c56. An analytical solution is obtained using Fourier series from which the resonant frequencies, mode shapes, and vibration confinement resulting from the electrode inertia are calculated and examined.

The Design And Fabrication Of A Microfluidic Reactor For Synthesis Of Cadmium Selenide Quantum Dots Using Silicon And Glass Substrates, Peter Robert Gonsalves

Master's Theses

A microfluidic reactor for synthesizing cadmium selenide (CdSe) quantum dots (QDs) was synthesized out of a silicon wafer and Pyrex glass. Microfabrication techniques were used to etch channels into the silicon wafer. Holes were wet-drilled into the Pyrex glass using a diamond-tip drill bit. The Pyrex wafer was anodically bonded to the etched silicon wafer to enclose the microfluidic reactor. Conditions for anodic bonding were created by exposing the stacked substrates to 300V at ~350oC under 5.46N of force. A syringe containing a room temperature CdSe solution was interfaced to the microfluidic reactor by using Poly (dimethylsiloxane) (PDMS) as an …

Controlling Nanoparticles Formation In Molten Metallic Bilayers By Pulsed-Laser Interference Heating, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman

Mathematics Faculty Publications

The impacts of the two-beam interference heating on the number of core-shell and embedded nanoparticles and on nanostructure coarsening are studied numerically based on the non-linear dynamical model for dewetting of the pulsed-laser irradiated, thin (< 20 nm) metallic bilayers. The model incorporates thermocapillary forces and disjoining pressures, and assumes dewetting from the optically transparent substrate atop of the reflective support layer, which results in the complicated dependence of light reflectivity and absorption on the thicknesses of the layers. Stabilizing thermocapillary effect is due to the local thickness-dependent, steady- state temperature profile in the liquid, which is derived based on the mean substrate temperature estimated from the elaborate thermal model of transient heating and melting/freezing. Linear stability analysis of the model equations set for Ag/Co bilayer predicts the dewetting length scales in the qualitative agreement with experiment.

Nanotopographic Cell Culture Substrate: Polymer-Demixed Nanotextured Films Under Cell Culture Conditions, Jung Yul Lim, Christopher A. Siedlecki, Henry J. Donahue

Department of Mechanical and Materials Engineering: Faculty Publications

Modulating physical cell culture environments via nanoscale substrate topographic modification has recently been of significant interest in regenerative medicine. Many studies have utilized a polymer-demixing technique to produce nanotextured films and showed that cellular adhesion, proliferation, and differentiation could be regulated by the shape and scale of the polymer-demixed nanotopographies. However, little attention has been paid to the topographic fidelity of the polymer-demixed films when exposed to cell culture conditions. In this brief article, two polymer-demixing systems were employed to assess topographic changes in polymer-demixed films after fibronectin (FN) extracellular matrix protein adsorption and after incubation in phosphate-buffered saline at …

Bacterial Isolation By Lectin-Modified Microengines, Susana Campuzano, Jahir Orozco, Daniel Kagan, Maria Guix, Wei Gao, Sirilak Sattayasamitsathit, Jonathan C. Claussen, Arben Merkoci, Joseph Wang

Jonathan C. Claussen

New template-based self-propelled gold/nickel/polyaniline/platinum (Au/Ni/PANI/Pt) microtubular engines, functionalized with the Concanavalin A (ConA) lectin bioreceptor, are shown to be extremely useful for the rapid, real-time isolation of Escherichia coli (E. coli) bacteria from fuel-enhanced environmental, food, and clinical samples. These multifunctional microtube engines combine the selective capture of E. coli with the uptake of polymeric drug-carrier particles to provide an attractive motion-based theranostics strategy. Triggered release of the captured bacteria is demonstrated by movement through a low-pH glycine-based dissociation solution. The smaller size of the new polymer-metal microengines offers convenient, direct, and label-free optical visualization of the captured bacteria and …

Controlling Nanoparticles Formation In Molten Metallic Bilayers By Pulsed-Laser Interference Heating, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman

Mikhail Khenner

The impacts of the two-beam interference heating on the number of core-shell and embedded nanoparticles and on nanostructure coarsening are studied numerically based on the non-linear dynamical model for dewetting of the pulsed-laser irradiated, thin (< 20 nm) metallic bilayers. The model incorporates thermocapillary forces and disjoining pressures, and assumes dewetting from the optically transparent substrate atop of the reflective support layer, which results in the complicated dependence of light reflectivity and absorption on the thicknesses of the layers. Stabilizing thermocapillary effect is due to the local thickness-dependent, steady- state temperature profile in the liquid, which is derived based on the mean substrate temperature estimated from the elaborate thermal model of transient heating and melting/freezing. Linear stability analysis of the model equations set for Ag/Co bilayer predicts the dewetting length scales in the qualitative agreement with experiment.

Ultrasound-Assisted Synthesis Of Mesoporous Β-Ni(Oh)2 And Nio Nano-Sheets Using Ionic Liquids, Tarek Alammar, Osama Shekhah, Jonas Wohlgemuth, Anja V. Mudring

Anja V. Mudring

Via a facile ultrasound synthesis from nickel acetate and sodium hydroxide with ionic liquids as the solvent and template it is possible to obtain nano-β-Ni(OH)2 of various dimensionalities depending on the reaction conditions with the ionic liquid (IL) being the most important factor. Scanning electron microscopy (SEM) imaging showed β-Ni(OH)2 to form as nanosheets, nanorods and nanospheres depending on the IL. ILs with strong to moderate hydrogen bonding capability like [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonylamide)), [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonylamide)) and [Edimim][Tf2N] (1-ethyl-2,3-diemethylimidazolium bis(trifluoromethanesulfonylamide)) lead to the formation of nanosheets whilst [Py4][Tf2N] (butyl-pyridinium bis(trifluoromethanesulfonylamide)) leads to nanoparticles and [N1888][Tf2N] (methyltrioctylammonium bis(trifluoromethanesulfonylamide)) to nanorods. Subsequent …

Usability Assessment Of Two Different Control Modes For The Master Console Of A Laparoscopic Surgical Robot, Xiaoli Zhang, Carl A. Nelson, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this study is to evaluate potential interface control modes for a compact fourdegree- of-freedom (4-DOF) surgical robot. The goal is to improve robot usability by incorporating a sophisticated haptics-capable interface. Two control modes were developed using a commercially available haptic joystick: (1) a virtually point-constrained interface providing an analog for constrained laparoscopic motion (3-DOF rotation and 1-DOF translation), and (2) an unconstrained Cartesian input interface mapping more directly to the surgical tool tip motions. Subjects (n = 5) successfully performed tissue identification and manipulation tasks in an animal model in point-constrained and unconstrained control modes, respectively, with …

Tool Sequence Trends In Minimally Invasive Surgery: Statistical Analysis And Implications For Predictive Control Of Multifunction Instruments, Carl A. Nelson, Evan Luxon, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

This paper presents an analysis of 67 minimally invasive surgical procedures covering 11 different procedure types to determine patterns of tool use. A new graph-theoretic approach was taken to organize and analyze the data. Through grouping surgeries by type, trends of common tool changes were identified. Using the concept of signal/noise ratio, these trends were found to be statistically strong. The tool-use trends were used to generate tool placement patterns for modular (multi-tool, cartridge-type) surgical tool systems, and the same 67 surgeries were numerically simulated to determine the optimality of these tool arrangements. The results indicate that aggregated tool-use data …

Method For Increasing The Efficiency Of Organic Photovoltaic Cells, Jinsong Huang, Yongbo Yuan

Department of Mechanical and Materials Engineering: Faculty Publications

The present invention is directed to an organic photovoltaic cell that contains one or more dipole regions generally disposed between an organic active region and the electrodes and a process for producing such an organic photovoltaic cell.

Moisture Damage Characterization Of Warm-Mix Asphalt Mixtures Based On Laboratory-Field Evaluation, Yong-Rak Kim, Jun Zhang, Hoki Ban

Department of Mechanical and Materials Engineering: Faculty Publications

This study presents laboratory evaluation integrated with field performance to examine two widely used warm-mix asphalt (WMA) approaches—foaming and emulsion technology. For a more realistic evaluation of the WMA approaches, trial pavement sections of the WMA mixtures and their counterpart hot-mix asphalt (HMA) mixtures were implemented in Antelope County, Nebraska. Field-mixed loose mixtures collected at the time of paving were transported to the laboratories to conduct various experimental evaluations of the individual mixtures. Among the laboratory tests, three (two conventional and one newly attempted) were performed to characterize moisture damage potential which is the primary focus of this study. From …

Thickness-Shear And Thickness-Twist Modes In An Oblate Elliptical Ceramic Cylinder And Energy Trapping In Contoured Acoustic Wave Resonators, Huijing He, Jiashi Yang, Yi-Hua Huang

Department of Mechanical and Materials Engineering: Faculty Publications

We study shear-horizontal motions of a piezoelectric ceramic cylinder with an oblate elliptical cross section and axial poling. Exact thickness-shear and thickness-twist vibration modes are obtained. These modes show energy trapping, i.e., the vibration is mainly confined near the thick, central region and decays to almost nothing near the edges. The results are useful for the understanding and design of contoured piezoelectric resonators for strong energy trapping.

Macro And Microfluidic Flows For Skeletal Regenerative Medicine, Brandon D. Riehl, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Fluid flow has a great potential as a cell stimulatory tool for skeletal regenerative medicine, because fluid flow-induced bone cell mechanotransduction in vivo plays a critical role in maintaining healthy bone homeostasis. Applications of fluid flow for skeletal regenerative medicine are reviewed at macro and microscale. Macroflow in two dimensions (2D), in which flow velocity varies along the normal direction to the flow, has explored molecular mechanisms of bone forming cell mechanotransduction responsible for flow-regulated differentiation, mineralized matrix deposition, and stem cell osteogenesis. Though 2D flow set-ups are useful for mechanistic studies due to easiness in in situ and post-flow …

Systems And Synthetic Biology Of The Vessel Wall, Jennifer Frueh, Nataly Maimari, Ying Lui, Zoltan Kis, Vikram Mehta, Negin Pormehr, Calum Grant, Emmanuel Chalkias, Mika Falck-Hansen, Sandra Bovens, Ryan M. Pedrigi, Taka Homma, Gianfillippo Coppola, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is intimately coupled to blood flow by the presence of predilection sites. The coupling is through mechanotransduction of endothelial cells and approximately 2000 gene are associated with this process. This paper describes a new platform to study and identify new signalling pathways in endothelial cells covering an atherosclerotic plaque. The identified networks are synthesized in primary cells to study their reaction to flow. This synthetic approach might lead to new insights and drug targets.

Finite Element Analysis Of The Contact Deformation Of Piezoelectric Materials, Ming Liu

Theses and Dissertations--Chemical and Materials Engineering

Piezoelectric materials in the forms of both bulk and thin-film have been widely used as actuators and sensors due to their electromechanical coupling. The characterization of piezoelectric materials plays an important role in determining device performance and reliability. Instrumented indentation is a promising method for probing mechanical as well as electrical properties of piezoelectric materials.

The use of instrumented indentation to characterize the properties of piezoelectric materials requires analytical relations. Finite element methods are used to analyze the indentation of piezoelectric materials under different mechanical and electrical boundary conditions.

For indentation of a piezoelectric half space, a three-dimensional finite element …

Monitoring The Wall Mechanics During Stent Deployment In A Vessel, Brian Steinert, Shijia Zhao, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Clinical trials have reported different restenosis rates for various stent designs . It is speculated that stentinduced strain concentrations on the arterial wall lead to tissue injury, which initiates restenosis . This hypothesis needs further investigations including better quantifications of non-uniform strain distribution on the artery following stent implantation. A non-contact surface strain measurement method for the stented artery is presented in this work. ARAMIS stereo optical surface strain measurement system uses two optical high speed cameras to capture the motion of each reference point, and resolve three dimensional strains over the deforming surface. As a mesh stent is deployed …

Sacrificial Structure Preforms For Thin Part Machining, Scott Smith, Robert Wilhelm, Brian Dutterer, Harish Cherukuri, Gaurav Goel

Department of Mechanical and Materials Engineering: Faculty Publications

Thin parts are often difficult to create by machining because they have insufficient static and dynamic stiffness. Accurate thin parts are difficult to achieve due to clamping forces, cutting forces, residual stresses, and chatter. Sacrificial structure preforms support the part during machining, but they are not part of the finished component. Preforms may be created in many ways, including forging, welding, gluing, casting, or additive processes. They can be used in many workpiece materials including metals, polymers, and ceramics. We describe a novel process that uses sacrificial structures to make machining insensitive to the thinness of finished parts.