Nanoscience and Nanotechnology Commons^™

Nanoscale Frictional Properties Of Nickel With One-Dimensional And Two-Dimensional Materials, Timothy K. Schlenger

Mechanical Engineering Undergraduate Honors Theses

When looking at the nanoscale, material interface interactions have been observed to exhibit particularly interesting properties. Our research looks into various combinations of carbyne and graphene atop a nickel block to look into the interface friction properties between them. Both the carbyne and graphene are tested using steered molecular dynamics (SMD) in sheering and peeling directions along the surface of the nickel block. These tests are then analyzed by comparing the magnitude of the acting force versus the displacement of the carbon allotrope sample across the nickel block. It is found that as the width of a carbon allotrope sample …

Direct Band Gap Gallium Antimonide Phosphide (Gasbxp1-X) For Solar Fuels., Harry Benjamin Russell

Electronic Theses and Dissertations

Photoelectrochemical water splitting has been identified as a promising route for achieving sustainable energy future. However, semiconductor materials with the appropriate optical, electrical and electrochemical properties have yet to be discovered. In search of an appropriate semiconductor to fill this gap, GaSbP, a semiconductor never tested for PEC performance is proposed here and investigated. Density functional theory (DFT+U) techniques were utilized to predict band gap and band edge energetics for GaSbP alloys with low amount of antimony. The overall objective of this dissertation is to understand the suitability of GaSb_xP_1-x alloys for photoelectrochemical water splitting application. Specifically, …

Acceleration Of Ddscat Computation By Parallelization On A Supercomputer, Manoj V. Seeram

Chemical Engineering Undergraduate Honors Theses

The DDSCAT software is enabled for use of MPI or OpenMP to distribute calculation of different particle orientations amongst multiple processors on a high performance system. Run times for these simulations have been tested to take hours or days however and simulating varying orientations is not always necessary. If a simulation with only one particle orientation is submitted, DDSCAT could still potentially parallelize the simulation by wavelength calculations but it is unknown if this is the case. In this paper, we will be (i) quantifying the reduction in computation time that MPI provides relative to an equivalent MPI disabled simulation …

Gold Nanoparticle Colorimetric Sensing Technology, Eve Borden

Nanoscale Science & Engineering (discontinued with class year 2014)

No abstract provided.

Size Controlled Formation Of A Collagen-Based Drug Delivery System, Leonardo Bezerra

Nanoscale Science & Engineering (discontinued with class year 2014)

This study investigates and troubleshoots various factors involved in the generation of collagen-based particles, such as volume of solution, temperature, and incubation time for the purposes of a potential colorectal cancer targeting drug vehicle. The particles were generated via loading into a gel mold and show a 20-200 fold decrease in size compared to those created only under chemical means.

Fundamental Interdiffusion Analysis Of Ruthenium And Cobalt Films, Bartlet Deprospo

Nanoscale Science & Engineering (discontinued with class year 2014)

No abstract provided.

Graphene’S Electronic Surface States On Metal Substrates, Alex De Palma

Nanoscale Science & Engineering (discontinued with class year 2014)

Graphene is a 2-­‐D sheet of sp2 bonded carbon atoms with exceptional electrical properties. Particularly, graphene has a very high carrier mobility (~200,000 cm2/V·∙s). This is largely due to graphene’s unique electronic structure, wherein charge carriers are effectively massless Dirac fermions. However, the unique electronic structure of graphene has been shown to be affected by the underlying substrate. In this study, we characterize the electronic structure of graphene on copper. Electron energy loss spectroscopy is employed to observe the surface plasmon excitations of graphene. A small pi plasmon excitation is observed, suggesting that the graphene/Cu interaction is weak and non-­‐covalent. …

Modeling Secondary Electron Trajectories In Scanning Electron Microscopes, Kevin Mcnamara, Joshua Miller

Nanoscale Science & Engineering (discontinued with class year 2014)

The efficiency of secondary electron collection by a scanning electron microscope detector is not generally known, particularly as the electric field on the detector is varied. It is often assumed that the detector collects almost all of the secondary electrons emitted from the sample. This works seeks to better understand the mechanism of secondary electron collection by the detector in order to optimize collection efficiency. The benefit of collecting more secondary electrons is the enhancement of the signal-to-noise ratio, which means better quality images can be obtained, allowing us to better understand the relationship between secondary electron images and the …

Modeling Secondary Electron Trajectories In Scanning Electron Microscopes, Joshua Miller, Kevin Mcnamara

Nanoscale Science & Engineering (discontinued with class year 2014)

The efficiency of secondary electron collection by a scanning electron microscope detector is not generally known, particularly as the electric field on the detector is varied. It is often assumed that the detector collects almost all of the secondary electrons emitted from the sample. This works seeks to better understand the mechanism of secondary electron collection by the detector in order to optimize collection efficiency. The benefit of collecting more secondary electrons is the enhancement of the signal-to-noise ratio, which means better quality images can be obtained, allowing us to better understand the relationship between secondary electron images and the …

Phase-Field Models For Simulating Physical Vapor Deposition And Microstructure Evolution Of Thin Films, James Stewart Jr.

Graduate Theses and Dissertations

The focus of this research is to develop, implement, and utilize phase-field models to study microstructure evolution in thin films during physical vapor deposition (PVD). There are four main goals to this dissertation. First, a phase-field model is developed to simulate PVD of a single-phase polycrystalline material by coupling previous modeling efforts on deposition of single-phase materials and grain evolution in polycrystalline materials. Second, a phase-field model is developed to simulate PVD of a polymorphic material by coupling previous modeling efforts on PVD of a single-phase material, evolution in multiphase materials, and phase nucleation. Third, a novel free energy functional …

Preparation Parameters Optimization And Electrocatalytic Properties Of Supported Au Nanoparticles, Rui Yao, Yu-Jiang Song, Huan-Qiao Li, Jia Li, Jian-Guo Liu

Journal of Electrochemistry

Due to interesting size effect, physical and chemical properties, nano-scale gold materials have been commonly used to catalytic reactions. However, the application of gold nanomaterials in the field of electrocatalysis is limited. Herein, we report the synthesis of gold nanparticles supported on carbon through chemical reduction of HAuCl₄ by NaBH₄ under mild conditions in the presence of surfactants as soft templates, carbon black or graphene as a support. We investigated a series of key reaction parameters, including reagent concentration, temperature, the types of carbon supports and surfactants. With the optimum synthetic parameters, we successfully obtained supported 1 ~ …

Preparation And Performance Of 3d Graphene Type Porous Carbon Employing Nano Fe(Oh)3 As Template For Oxygen Reduction Catalyst, Chong-Yun Sun, Zhong-Fang Li, Xue-Wei Lu, Xi-Zhan Zhong, Yu-Rong Liu

Journal of Electrochemistry

The 3D graphene type porous carbon was prepared using coal tar pitch as carbon source and nano Fe(OH)₃ as template. Optimal conditions for the catalytic oxygen reduction performance were determined as: the mass ratio of coal tar, nano Fe(OH)₃ and KOH is 6:8:4; the pyrolysis temperature is 800 ^oC. SEM images show that the products have uniformly porous structure. TEM images demonstrate that the products are porous with foam shapes. HRTEM images further indicate that the products have formed several-layers 3D graphene structure, which are also supported by XRD and Raman data, and the pore size mainly …

Syntheses Of Carbon Paper Supported High-Index Faceted Pt Nanoparticles And Their Performance In Direct Formic Acid Fuel Cells, Long Huang, Mei Zhan, Yu-Cheng Wang, Yan-Fen Lin, Shuo Liu, Ting Yuan, Hui Yang, Shi-Gang Sun

Journal of Electrochemistry

Direct formic acid fuel fuels (DFAFCs) are promising energy source for portable electronic devices. Palladium (Pd) is more active than platinum (Pt) for the formic acid electrooxidation. However, the stability of Pd is much poorer than that of Pt. Unfortunately, the ultra-low natural abundance of the Pt makes it extremely expensive and limits its application as a fuel cell catalyst. Boosting both the activity and stability of Pt nanoparticles to enhance their efficiency is urgent. As previous works illustrated, nanoparticles enclosed with high-index facets usually bare a higher activity toward fuel cell related reactions than those nanoparticles with low-index facet. …

Al/Ti Nanostructured Multilayers: From Mechanical, Tribological, To Corrosion Properties, Sina Izadi

USF Tampa Graduate Theses and Dissertations

Nanostructured metallic multilayers (NMMs) are well-known for their high strength in smaller bilayer thicknesses. Six Al/Ti (NMM) with different individual layer thickness were tested for their mechanical hardness using a nanoindentation tool. Individual layer thicknesses were chosen carefully to cover the whole confined layer slip (CLS) model. Nano-hardness had a reverse relation with the square root of individual layer thickness and reached a steady state at ~ 5 nm bilayer thickness. Decreasing the layer bilayer thickness from ~ 104 nm to ~ 5 nm, improved the mechanical hardness up to ~ 101%. Residual stresses were measured using grazing incident X-ray …

Molecular Combing Of Dna Nanofibers And Comparison To Electrospinning, Tanner L. Buresh

UCARE: Research Products

The goal of these experiments was to create DNA nanofibers through the method of molecular combing (MC) and then compare the MC fibers to fibers created with electrospinning (ES). The experiment was designed and initial samples were created. After confirming that the method would succeed in creating DNA fibers, several parametric studies were performed in order to optimize the experiment and create the most uniform fibers possible. The parametric studies were done on the following variables: substrate material, pH level of DNA solution, and DNA solution concentration. After completion of all experiments, it was determined that although fibers could be …

The Change In Nutritional Status In Traumatic Brain Injury Patients: A Retrospective Descriptive A Retrospective Descriptive Study, Dina A. Masha'al

USF Tampa Graduate Theses and Dissertations

There is a high prevalence in malnutrition among traumatic brain injury (TBI) due to the hypermetabolism and hypercatabolism which develop post injury. Traumatic brain injury patients are different, even among themselves, in their energy requirements and response to nutritional therapy. This implies that there are other factors that affect the energy intake of these patients and enhance the incidence of malnutrition.

This dissertation study examines the nutritional status of TBI patients upon admission to the intensive care unit (ICU) and during their hospital stay to describe baseline status, detect changes in nutritional status over 7 days, and identify the factors …

Visible-Light-Responsible Co-Catalysts Enhanced By Graphene For Solar Energy Harvesting, Chen Ying

Masters Theses & Specialist Projects

This study focuses on the visible light response of hetero-structures of TiO2-graphene- MoS2 for solar energy harvestings. The commercial P25 TiO2 nano-particles, and selfprepared layered reduced graphene oxides (RG) and MoS2 were assembled for the targeted hetero-structure materials as visible-light responsible solar harvesting cocatalysts. The hydrothermal method was applied for nano-material synthesis, the reduction of graphene oxides, and bonding formation. Multiple characterization methods (SEM-TEM, XRD, XPS, UV-VIS, PL, FT-IR, TGA) have been applied to understand the electron-hole pair separation and recombination, and performance tuning in their visible-light photo-catalysis rhodamine B (Rh.B) degradations process

Compared to TiO2, an obvious red shift …

Immobilization Of Cellulase For Large Scale Reactors To Reduce Cellulosic Ethanol Cost, Dezhi Zhang

Doctoral Dissertations

Cellulosic ethanol is an alternative renewable energy source. Cellulase used in the production of cellulosic ethanol is very expensive. The difficulty in separating cellulase from the cellulose solution after the hydrolysis process limits the reusability of the cellulase, which highly precludes the scales of this application because of the high cost of the enzyme. Immobilization of cellulase provides a promising approach to allow the enzyme to be recycled, thus reducing the production cost. This research focused on immobilizing cellulase for reuse to reduce the cellulosic ethanol cost.

Four immobilization techniques were explored for the immobilization of cellulase on four different …

Enhanced Bioactive Scaffolds For Bone Tissue Regeneration, Sonali Karnik

Doctoral Dissertations

Bone injuries are commonly termed as fractures and they vary in their severity and causes. If the fracture is severe and there is loss of bone, implant surgery is prescribed. The response to the implant depends on the patient's physiology and implant material. Sometimes, the compromised physiology and undesired implant reactions lead to post-surgical complications. [4, 5, 20, 28] Efforts have been directed towards the development of efficient implant materials to tackle the problem of post-surgical implant failure. [ 15, 19, 24, 28, 32]

The field of tissue engineering and regenerative medicine involves the use of cells to form a …

Clay Nanotube Composites For Antibacterial Nanostructured Coatings, Christen J. Boyer

Doctoral Dissertations

A surging demand for the development of new antimicrobial nanomaterials exists due to the frequency of medical device-associated infections and the transfer of pathogens from highly touched objects. Naturally occurring halloysite clay nanotubes (HNTs) have shown to be ideal particles for polymer reinforcement, time-release drug delivery, nano-reactor synthesis, and as substrate material for nanostructured coatings.

This research demonstrates the feasibility of a novel method for coating HNTs with metals for antibacterial applications. The first ever ability to coat HNTs through electrolysis was developed for customizable and multi-functional antibacterial nanoparticle platforms. HNTs were investigated as substrate for the deposition of copper …