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Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth McNeel 2018 Louisiana State University and Agricultural and Mechanical College

Biomedical Applications Of Hydrogels And Gumbos, Kelsey Elizabeth Mcneel

LSU Doctoral Dissertations

Sodium deoxycholate (NaDC) is a small bile salt that was used in this dissertation to produce gelation of tris(hydroxymethyl)amino-methane (TRIS) solutions above, below, and near the pKa of NaDC. These solutions respectively yielded a neutral gelator, a charged gelator, and a mixture of each. Impacts of ionic interactions on gel formation were studied in detail and showed that pH can be used to modify many hydrogel properties including sol-gel temperature, crystallinity, and mechanical strength. It was also observed that pH modification of the hydrogels affected nanoparticle formation. Nanoparticles derived from a Group of Uniform Materials Based on Organic ...


Hybrid Electrochemical Capacitors: Materials, Optimization, And Miniaturization, Richa Agrawal 2018 Department of Mechanical and Materials Engineering, Florida International University

Hybrid Electrochemical Capacitors: Materials, Optimization, And Miniaturization, Richa Agrawal

FIU Electronic Theses and Dissertations

With the ever-advancing technology, there is an incessant need for reliable electrochemical energy storage (EES) components that can provide desired energy and power. At the forefront of EES systems are electrochemical capacitors (ECs), also known as supercapacitors that typically have higher power and superior cycle longevity but lower energy densities than their battery counterparts. One of the routes to achieve higher energy density for ECs is using the hybrid EC configuration, which typically utilizes a redox electrode coupled with a counter double-layer type electrode.

In this dissertation, both scale-up (coin-cell type) as well as scale-down (on-chip miniaturized) hybrid ECs were ...


Synthesis, And Structural, Electrochemical, And Magnetic Property Characterization Of Promising Electrode Materials For Lithium-Ion Batteries And Sodium-Ion Batteries, Ruixin Han 2018 University of Kentucky

Synthesis, And Structural, Electrochemical, And Magnetic Property Characterization Of Promising Electrode Materials For Lithium-Ion Batteries And Sodium-Ion Batteries, Ruixin Han

Theses and Dissertations--Chemistry

Iron oxides, have been widely studied as promising anode materials in lithium-ion batteries (LIBs) for their high capacity (≈ 1000 mA h g-1 for Fe2O3 and Fe3O4,), non-toxicity, and low cost. In this work, β-FeOOH has been evaluated within a LIB half-cell showing an excellent capacity of ≈ 1500 mA h g-1 , superior to Fe2O3 or Fe3O4. Reaction mechanism has been proposed with the assistance of X-ray photoelectron spectroscopy (XPS). Various magnetic properties have been suggested for β-FeOOH such as superparamagnetism, antiferromagnetism and complex magnetism, for which, size ...


Probing The Surface Of Nanodiamonds At Stanford Synchrotron Radiation Lightsource And San Jose State University, Jocelyn Valenzuela, Jackson Earl, Cynthia Melendrez, Grace Jeanpierre, Dennis Nordlund, Abraham Wolcott 2018 San Jose State University

Probing The Surface Of Nanodiamonds At Stanford Synchrotron Radiation Lightsource And San Jose State University, Jocelyn Valenzuela, Jackson Earl, Cynthia Melendrez, Grace Jeanpierre, Dennis Nordlund, Abraham Wolcott

STAR (STEM Teacher and Researcher) Presentations

The nitrogen-vacancy center in diamond is a promising tool in oncology, electric field sensing, and quantum cryptography. High-pressure high-temperature (HPHT) nanodiamonds (NDs) are prime contenders for these fields because they host nitrogen-vacancy centers (NVCs) which are applicable towards cancer detection and electric and magnetic field sensing. However, to apply HPHT NDs to these fields, the surface must first be functionalized—a difficult process because of the inert nature of the surface. The project at hand focuses on surface modification of HPHT NDs with amines to allow for further bioconjugation of small molecules and plasmonic shells. This is done via liquid-phase ...


Characterization Of Tetraethyl Orthosilicate-Based Dynamic Hydrogels For Use As Reversible 3-D Cell Culture Matrices, Krisitan Stipe 2018 University of Montana, Missoula

Characterization Of Tetraethyl Orthosilicate-Based Dynamic Hydrogels For Use As Reversible 3-D Cell Culture Matrices, Krisitan Stipe

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.


Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts 2018 VCU

Radical Chemistry In A Femtosecond Laser Plasma: Photochemical Reduction Of Ag+ In Liquid Ammonia Solution, Victoria K. Meader, Mallory G. John, Laysa M. Frias Batista, Syeda Ahsan, Katharine M. Tibbetts

Chemistry Publications

Plasmas with dense concentrations of reactive species such as hydrated electrons and hydroxyl radicals are generated from focusing intense femtosecond laser pulses into aqueous media. These radical species can reduce metal ions such as Au3+ to form metal nanoparticles (NPs). However, the formation of H2O2 by the recombination of hydroxyl radicals inhibits the reduction of Ag+ through back-oxidation. This work has explored the control of hydroxyl radical chemistry in a femtosecond laser-generated plasma through the addition of liquid ammonia. The irradiation of liquid ammonia solutions resulted in a reaction between NH3 and OH·, forming peroxynitrite and ONOO−, and significantly reducing ...


Extracting Interface Locations In Multilayer Polymer Waveguide Films Using Scanning Angle Raman Spectroscopy, Jonathan M. Bobbitt, Emily A. Smith 2018 Iowa State University and Ames Laboratory

Extracting Interface Locations In Multilayer Polymer Waveguide Films Using Scanning Angle Raman Spectroscopy, Jonathan M. Bobbitt, Emily A. Smith

Ames Laboratory Accepted Manuscripts

There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and scanning angle (SA) Raman spectroscopy in combination with appropriate data models can provide this information. A SA Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7- to 80-nm axial spatial resolution. The SA Raman method acquires Raman spectra as the incident angle of light upon a prism-coupled thin film is scanned. Six multilayer films consisting of poly ...


Rare Earth Arylsilazido Compounds With Inequivalent Secondary Interactions, Kasuni C. Boteju, Suchen Wan, Amrit Venkatesh, Arkady Ellern, Aaron Rossini, Aaron D. Sadow 2018 Iowa State University and Ames Laboratory

Rare Earth Arylsilazido Compounds With Inequivalent Secondary Interactions, Kasuni C. Boteju, Suchen Wan, Amrit Venkatesh, Arkady Ellern, Aaron Rossini, Aaron D. Sadow

Ames Laboratory Accepted Manuscripts

A new bulky silazido ligand, –N(SiHMe2)Dipp (Dipp = C6H3-2,6-iPr2) supports planar, three-coordinate homoleptic rare earth complexes Ln{N(SiHMe2)Dipp}3 (Ln = Sc, Y, Lu) that each contain three secondary Ln↼HSi interactions and one agostic CH bond. Y{N(SiHMe2)Dipp}3 and acetophenone react via hydrosilylation, rather than by insertion into the Y–N bond or enolate formation.


Richard Smalley And The Materials Of Tomorrow: The Discovery, Properties, And Science Of Fullerenes, Creighton A. Jackson 2018 Parkland College

Richard Smalley And The Materials Of Tomorrow: The Discovery, Properties, And Science Of Fullerenes, Creighton A. Jackson

Natural Sciences Poster Sessions

These are slides accompanying a presentation given at the Natural Sciences Poster Session at Parkland College outlining the properties of and ongoing research pertaining to fullerenes in materials science.


Physicochemical, Spectroscopic Properties, And Diffusion Mechanisms Of Small Hydrocarbon Molecules In Mof-74-Mg/Zn: A Quantum Chemical Investigation, Gemechis Degaga 2018 Michigan Technological University

Physicochemical, Spectroscopic Properties, And Diffusion Mechanisms Of Small Hydrocarbon Molecules In Mof-74-Mg/Zn: A Quantum Chemical Investigation, Gemechis Degaga

Dissertations, Master's Theses and Master's Reports

In petroleum refining industries, the fracturing process allows for the cracking of long-chain hydrocarbons into a mixture of small olefin and paraffin molecules that are then separated via the energetically and monetarily demanding cryogenic distillation process. In an attempt to mitigate both energetic and capital consumptions, selective sorption of light hydrocarbons by tunable sorbents, such as metal-organic frameworks (MOFs), appears to be the most promising alternative for a more efficient gas separation process. MOFs are novel porous materials assembled from inorganic bricks connected by organic linkers. From a crystal engineering stand point, MOFs are advantageous in creating a range of ...


Modeling Of Diffusivity For 2d Vacancy Nanopits And Comparison With 2d Adatom Nanoislands On Metal(100) Surfaces Including Analysis For Ag(100), King C. Lai, Da-Jiang Liu, Patricia A. Thiel, James W. Evans 2018 Iowa State University and Ames Laboratory

Modeling Of Diffusivity For 2d Vacancy Nanopits And Comparison With 2d Adatom Nanoislands On Metal(100) Surfaces Including Analysis For Ag(100), King C. Lai, Da-Jiang Liu, Patricia A. Thiel, James W. Evans

Ames Laboratory Accepted Manuscripts

Diffusion coefficients, DN, for 2D vacancy nanopits are compared with those for 2D homoepitaxial adatom nanoislands on metal(100) surfaces, focusing on the variation of DN with size, N. Here, Nis measured in missing atoms for pits and adatoms for islands. Analysis of DN is based on kinetic Monte Carlo simulations of a tailored stochastic lattice-gas model, where pit and island diffusion are mediated by periphery diffusion, i.e., by edge atom hopping. Precise determination of DNversus N for typical parameters reveals a cyclical variation with an overall decrease in magnitude for increasing moderate ...


Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen 2018 West Chester University of Pennsylvania

Hierarchical Porous Silicon And Porous Silicon Nanowires Produced With Regenerative Electroless Etching (Reetching) And Metal Assisted Catalytic Etching (Mace), Kurt W. Kolasinski, Bret A. Unger, Haibo Yu, Alexis T. Ernst, Mark Aindow, Ermei Mäkilä, Jarno Salonen

Chemistry Faculty Publications

ReEtching produces nanostructured silicon when a catalytic agent, e.g. dissolved V2O5, is used to facilitate etching between Si and H2O2. H2O2 regenerates dissolved V in a 5+ oxidation state, which initiates etching by injecting holes into the Si valence band. Independent control over the extent of reaction (controlled by the amount of H2O2 added) and the rate of reaction (controlled by the rate at which H2O2 is pumped into the etchant solution) allows us to porosify Si substrates of arbitrary size, shape and doping, including wafers, single-crystal powders, polycrystalline powders, metallurgical grade powder, Si nanowires, Si pillars and Si ...


Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski 2018 Renaissance Academy Charter School, Phoenixville, PA

Crystallographically Defined Silicon Macropore Membranes, Shannon C. Knight, Bret A. Unger, Kurt W. Kolasinski

Chemistry Faculty Publications

Laser ablation with nanosecond-pulsed Nd:YAG laser irradiation combined with anisotropic alkaline etching of Si wafers creates 4–20 µm macropores that extend all the way through the wafer. The walls of these macropores are crystallographically defined by the interaction of the anisotropy of the etchant with the orientation of the single-crystal silicon substrate: rectangular/octagonal on Si(001), parallelepiped on Si(110), triangular/hexagonal on Si(111). Laser ablation can create pillars with peak-tovalley heights of over 100 µm. However, with nanosecondpulsed irradiation at 532 nm, the majority of this height is created by growth above the original plane ...


Silicon Surface Photochemistry, Kurt W. Kolasinski 2018 West Chester University of Pennsylvania

Silicon Surface Photochemistry, Kurt W. Kolasinski

Chemistry Faculty Publications

General concepts of photochemistry on metal and semiconductor surfaces are elucidated. These concepts are then applied more specifically to describe photochemical transformation of molecules on and with silicon surfaces. The mechanisms by which light can induce chemical reactions following electronic excitation are described. Processes reviewed include photodissociation of adsorbed molecules, photo-induced attachment of organic molecules and photo-induced corrosion.


Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei 2018 West Chester University of Pennsylvania

Plume And Nanoparticle Formation During Laser Ablation, Kurt W. Kolasinski, Mool C. Gupta, Leonid V. Zhigilei

Chemistry Faculty Publications

The processes that lead to material ejection when a solid sample is irradiated near and above the pulsed laser ablation threshold are discussed. Emphasis is placed on the thermal and mechanical mechanisms that occur during pulsed laser irradiation of metals and semiconductors. Distinctions are drawn between ultrafast-pulsed irradiation, which occurs under stress confinement, and shortpulsed irradiation, in which stress is released during the laser pulse. Similarly, the distinctions between the spallation and phase explosion regimes are discussed. Spallation is only possible when the time of the laser heating is shorter than the time needed for mechanical equilibration of the heated ...


Electron Enhanced Atomic Layer Deposition (Ee-Ald) For Room Temperature Growth Of Gallium Nitride, Silicon, And Boron Nitride Films, Jaclyn Kelly Sprenger 2018 University of Colorado at Boulder

Electron Enhanced Atomic Layer Deposition (Ee-Ald) For Room Temperature Growth Of Gallium Nitride, Silicon, And Boron Nitride Films, Jaclyn Kelly Sprenger

Chemistry & Biochemistry Graduate Theses & Dissertations (1986-2018)

Electron enhanced atomic layer deposition (EE-ALD) can drastically reduce the temperatures required for film growth through electron stimulated desorption (ESD) of surface species. The desorption process creates highly reactive “dangling bond” surface sites. Precursors can then adsorb efficiently on the dangling bonds. EE-ALD enables deposition of thin films on thermally sensitive substrates and growth of laminate materials where alloying would occur at traditional processing temperatures.

We have demonstrated the EE-ALD of polycrystalline GaN, BN, and amorphous Si at room temperature (27˚C). Film growth was performed using alternating exposures of the appropriate precursors and low energy electrons (~100 eV). X-ray ...


Designing Materials For Inorganic And Living Photocatalytic Systems For Air, Water, And Co2 Reduction From Sunlight, Yuchen Ding 2018 University of Colorado at Boulder

Designing Materials For Inorganic And Living Photocatalytic Systems For Air, Water, And Co2 Reduction From Sunlight, Yuchen Ding

Chemistry & Biochemistry Graduate Theses & Dissertations (1986-2018)

Several strategies are currently being investigated for conversion of incident sunlight into chemical fuels, with readily available chemical feedstocks like air, water, and carbon-dioxide. This thesis focuses on research approach on designing high-efficiency and high-selective photocatalytic materials, ranging from inexpensive and stable inorganic photocatalysts to living nano-biohybrid organisms to achieve solar energy conversion.

This thesis is divided into multiple sections based on the materials and concepts in designing high-efficient and high-selective solar fuel generator. After a brief introduction of photocatalysis in Chapter 1, we describe a novel electrochemical anodization technique for making a wide-variety of doped metal-oxide nanotubes. Using optoelectronic ...


Photo-Tunable Dynamics Studies On Solitonic Structures In Chiral Nematic Liquid Crystals, Changda Liu 2018 University of Colorado, Boulder

Photo-Tunable Dynamics Studies On Solitonic Structures In Chiral Nematic Liquid Crystals, Changda Liu

Undergraduate Honors Theses

Rich dynamic behavior of solitons has attracted a great deal of interest in fields of physics ranging from fluid dynamics to optics. Unlike in those fields, topological solitons are extremely accessible when using liquid crystals as a host medium, providing a model experimental system for discovering the physics behind. The research presented in this thesis studied the photo-tunable dynamics of a topological solitonic field configuration dubbed “torons” in chiral nematic liquid crystals, and we show that precise-controlling of the toron motions, forming reconfigurable lattice-structures of torons, and potentially controlling the electric-driven toron “squirming” motions, can be achieved with light exposure.


Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization And Magnetostructural Properties, Riaz Ahamed Ahamed Khan, Reza Ghomashchi, Zonghan Xie, lei chen 2018 Edith Cowan University

Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization And Magnetostructural Properties, Riaz Ahamed Ahamed Khan, Reza Ghomashchi, Zonghan Xie, Lei Chen

ECU Publications Post 2013

An overview of the processing, characterization and magnetostructural properties of ferromagnetic NiMnX (X = group IIIA-VA elements) Heusler alloys is presented. This type of alloy is multiferroic-exhibits more than one ferroic property-and is hence multifunctional. Examples of how different synthesis procedures influence the magnetostructural characteristics of these alloys are shown. Significant microstructural factors, such as the crystal structure, atomic ordering, volume of unit cell, grain size and others, which have a bearing on the properties, have been reviewed. An overriding factor is the composition which, through its tuning, affects the martensitic and magnetic transitions, the transformation temperatures, microstructures and, consequently, the ...


Optimal Sample Formulations For Dnp Sens: The Importance Of Radical-Surface Interactions, Frederic A. Perras, Linlin Wang, J. Sebastian Manzano, Umesh Chaudhary, Naftali N. Opembe, Duane D. Johnson, Igor I. Slowing, Marek Pruski 2018 Ames Laboratory

Optimal Sample Formulations For Dnp Sens: The Importance Of Radical-Surface Interactions, Frederic A. Perras, Linlin Wang, J. Sebastian Manzano, Umesh Chaudhary, Naftali N. Opembe, Duane D. Johnson, Igor I. Slowing, Marek Pruski

Ames Laboratory Accepted Manuscripts

The efficacy of dynamic nuclear polarization (DNP) surface-enhanced NMR spectroscopy (SENS) is reviewed for alumina, silica, and ordered mesoporous carbon (OMC) materials, with vastly different surface areas, as a function of the biradical concentration. Importantly, our studies show that the use of a “one-size-fits-all” biradical concentration should be avoided when performing DNP SENS experiments and instead an optimal concentration should be selected as appropriate for the type of material studied as well as its surface area. In general, materials with greater surface areas require higher radical concentrations for best possible DNP performance. This result is explained with the use of ...


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