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Superconductivity Versus Structural Phase Transition In The Closely Related Bi2rh3.5s2 And Bi2rh3s2, Udhara S. Kaluarachchi, Weiwei Xie, Qisheng Lin, Valentin Taufour, Sergey L. Bud'ko, Gordon J. Miller, Paul C. Canfield 2016 Iowa State University

Superconductivity Versus Structural Phase Transition In The Closely Related Bi2rh3.5s2 And Bi2rh3s2, Udhara S. Kaluarachchi, Weiwei Xie, Qisheng Lin, Valentin Taufour, Sergey L. Bud'ko, Gordon J. Miller, Paul C. Canfield

Qisheng Lin

Single crystals of Bi2Rh3S2 and Bi2Rh3.5S2 were synthesized by solution growth, and the crystal structures and thermodynamic and transport properties of both compounds were studied. In the case ofBi2Rh3S2, a structural first-order transition at around 165 K is identified by single-crystal diffraction experiments, with clear signatures visible in resistivity, magnetization, and specific heat data. No superconducting transition for Bi2Rh3S2 was observed down to 0.5 K. In contrast, no structural phase transition at high temperature was observed for Bi2Rh3.5S2; however, bulk superconductivity with a critical temperature, Tc≈1.7 K, was observed. The Sommerfeld coefficient γ and the ...


Synthesis Of Metal-Containing Phosphines And Their Use In Coordination, Polymer, And Materials Chemistry, Amir Rabiee Kenaree 2016 The University of Western Ontario

Synthesis Of Metal-Containing Phosphines And Their Use In Coordination, Polymer, And Materials Chemistry, Amir Rabiee Kenaree

Electronic Thesis and Dissertation Repository

This thesis describes the investigation of a novel strategy for the synthesis of metal-containing small molecules, polymers, and nanomaterials. In this context, a new family of air-stable, homo- and heterometallic primary, secondary, and tertiary phosphines were prepared via the radical-initiated hydrophosphination reaction of PH3 with vinylferrocene and/or vinylruthenocene. The full characterization of the phosphines confirmed their targeted structures and proved that the properties of the starting metallocenes are reflected in those of the resulting phosphines.

To study the coordination behavior of this family of phosphines, primary, secondary, and tertiary ethylferrocene phosphines were reacted with Group 6 metal carbonyl ...


Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, Joseph A. Paquette 2016 The University of Western Ontario

Synthesis Of Metal-Containing Polymers And Stable Organic Radical-Containing Polymers And Their Use As Advanced Functional Materials, Joseph A. Paquette

Electronic Thesis and Dissertation Repository

The work presented in this thesis details the synthesis and characterization of two different families of multifunctional polymers. The first family involved the incorporation of stable 6-oxoverdazyl radicals into polymer scaffolds. This was originally achieved by the polymerization of the radical precursors, phenyl- and isopropyl-6-oxotetrazanes, followed by post-polymerization oxidation to afford the phenyl- and isopropyl-6-oxoverdazyl polymers. A second methodology involved the direct polymerization of isopropyl-6-oxoverdazyl radicals using ring-opening metathesis polymerization (ROMP) to afford polymers with controlled molecular weights and narrow molecular weight distributions. The polymers were characterized by the close comparison of the physical and spectroscopic properties ...


Polyol Induced Partitioning Of Essential Oils In Aqueous Organic Solvent Mixtures, Thomas DelMastro 2016 Seton Hall University

Polyol Induced Partitioning Of Essential Oils In Aqueous Organic Solvent Mixtures, Thomas Delmastro

Seton Hall University Dissertations and Theses (ETDs)

Polyol Induced Extraction (PIE) was developed and patented at Seton Hall University by Drs. John R. Sowa Jr., Wyatt R. Murphy, and Mithilesh Deshpande. It was originally discovered and implemented as a method to recycle and reuse waste acetonitrile during the production shortage in 2008. Through the use of PIE, a solvent mixture containing acetonitrile and water can be separated by employing a polyol mass separating agent, which induces a phase separation. The system is separated into its corresponding aqueous and organic phases, with the organic phase being a highly purified organic liquid. Based on the successful experimental results that ...


Design And Synthesis Of Novel Octacarboxy Porphyrinic Metal-Organic Frameworks, Jacob A. Johnson 2016 University of Nebraska - Lincoln

Design And Synthesis Of Novel Octacarboxy Porphyrinic Metal-Organic Frameworks, Jacob A. Johnson

Student Research Projects, Dissertations, and Theses - Chemistry Department

Metal-Organic Frameworks (MOFs) are a class of nanoporous crystalline materials constructed via the interconnection between metal-ions/inorganic clusters and organic ligands. Since the surface area, pore size and distribution, and chemical functionalities of MOFs are highly tunable via the judicious combinations of inorganic clusters and organic ligands, MOFs have attracted intensive interests for a variety of applications including gas adsorption and separation, catalysis, chemical sensing, and drug delivery among others. Porphyrin based ligands are of particular interest for building functional MOFs due to their unique photo-, electro-, and catalytic properties. In addition, the four-fold symmetry of porphyrin ligands offers an ...


Development Of An F-Element Separation Chemistry Using Solid Electrolytes, Kristian Guy Myhre 2016 University of Tennessee, Knoxville

Development Of An F-Element Separation Chemistry Using Solid Electrolytes, Kristian Guy Myhre

Doctoral Dissertations

The f‒elements (lanthanides and actinides) have numerous applications and are critically important to many industries, including the energy, security, and medical industries. One of the barriers to increased use and availability of the f‒elements is the difficulty in separating them from each other due to their similar chemistries. This is especially true of the trivalent f‒elements (lanthanides and minor actinides). The development of separation techniques that maximize the differences in the physicochemical properties of the f‒elements is therefore an important area of research. For these reasons, an effort was undertaken to explore the use of solid ...


Graphene Quantum Dots Electrochemistry And Development Of Sensitive Electrochemical Biosensor [Hybrid Poster 2-B], Tyler Smith, Alexander Banaszak 2016 Western Kentucky University

Graphene Quantum Dots Electrochemistry And Development Of Sensitive Electrochemical Biosensor [Hybrid Poster 2-B], Tyler Smith, Alexander Banaszak

Posters-at-the-Capitol

Graphene quantum dots (GQDs) are zero-dimensional material derived from graphene derivatives with characteristics from the structure of graphene with quantum confinement and edge effects possessing unique properties. Intense research activity in GQDs is attributed to their novel physical-chemical phenomena arising from the sp2-bonded carbon core surrounded with edge functional moieties. In this work, GQDs of optimal 5-7 nm size are investigated for their fundamental electrochemical properties and use in electrochemical sensing including enzyme-based glucose biosensor. Glucose oxidase (GOx) was immobilized on GQDs modified glassy carbon (GC) and the UV-Vis absorption and fluorescence spectroscopy, electron microscopy, cyclic and ...


Molecular Sensitivity And Selectivity Of Metal Nanoparticles Decorated Graphene As ‘Smart’ Surface-Enhanced Raman Scattering (Sers) Platforms [Hybrid Poster 2-A], Alexander Banaszak, Tyler Smith 2016 Western Kentucky University

Molecular Sensitivity And Selectivity Of Metal Nanoparticles Decorated Graphene As ‘Smart’ Surface-Enhanced Raman Scattering (Sers) Platforms [Hybrid Poster 2-A], Alexander Banaszak, Tyler Smith

Posters-at-the-Capitol

Raman scattering signal enhancement that uses graphene as support, graphene-enhanced Raman scattering (GERS), is a recent phenomenon. It can produce clean and reproducible Raman signals of chemical molecules with significantly enhanced signal intensity in contrast to traditional surface- (SERS) and tip- enhanced Raman scattering (TERS) techniques. While enhancement in SERS and TERS arise due to the electromagnetic mechanism, GERS also relies on a chemical mechanism and therefore shows unique molecular sensitivity and selectivity. In this work, we developed graphene materials decorated with noble metal (silver and gold) nanoparticles for detection of different chemical molecules e.g. methylene blue (MB) and ...


Synthetic Development Of Low Dimensional Materials, Long Men, Miles A. White, Himashi P. Andaraarachchi, Bryan A. Rosales, Javier Vela 2016 Iowa State University

Synthetic Development Of Low Dimensional Materials, Long Men, Miles A. White, Himashi P. Andaraarachchi, Bryan A. Rosales, Javier Vela

Chemistry Publications

In this invited paper, we highlight some of our most recent work on the synthesis of low dimensional nanomaterials. Current graduate students and members of our group present four specific case systems: Nowotny–Juza phases, nickel phosphides, germanium-based core/shells, and organolead mixed-halide perovskites. Each system is accompanied by commentary from the student involved, which explains the motivation behind their work, as well as a protocol detailing the key experimental considerations involved in their synthesis. We trust these and similar efforts will help further advance our understanding of the broader field of synthetic nanomaterials chemistry, while, at the same time ...


Solvothermal Preparation And Characterization Of Superstructures Of Nanoscopic Cds And Cdse, Tetyana Levchenko 2016 The University of Western Ontario

Solvothermal Preparation And Characterization Of Superstructures Of Nanoscopic Cds And Cdse, Tetyana Levchenko

Electronic Thesis and Dissertation Repository

Micrometer-sized superparticles, self-assembled from metallic or semiconducting nanoclusters, can be used as convenient building blocks for preparing functional materials, utilizing the electronic and photophysical properties resulting from the quantum confinement as well as from the coupling between individual nanoscopic constituents.

This research aimed at developing a novel approach utilizing the conversion of a cadmium phenylchalcogenolate precursor (Me4N)2[Cd(EPh)4] (where E = S or Se) under solvothermal conditions for the preparation of nanoscopic CdE, including both crystalline superlattices of large discrete nanoclusters and superstructures with more complex morphology. In particular, 3D cubic superlattices of molecular CdS nanoclusters ...


Polytypism And Unique Site Preference In Liznsb: A Superior Thermoelectric Reveals Its True Colors, Miles A. White, Gordon J. Miller, Javier Vela 2016 Iowa State University

Polytypism And Unique Site Preference In Liznsb: A Superior Thermoelectric Reveals Its True Colors, Miles A. White, Gordon J. Miller, Javier Vela

Chemistry Publications

The first example of polytypism in the I–II–V semiconductors has been demonstrated with the synthesis of cubic LiZnSb by a low-temperature solution-phase method. This phase exhibits a unique coloring pattern that is novel for this class of compounds. The choice of site configuration has a considerable impact on the band structure of these materials, which in turn affects the transport properties. While the hexagonal polytype has been suggested as a promising n-type and extremely poor p-type thermoelectric material, the cubic analogue is calculated to have high efficiencies for both the n- and p-type derivatives (1.64 and 1 ...


Effects Of Sintering Parameters On The Microstructure And Tensile Properties Of In Situ (Ti5si3 + Tibw)/Ti6al4v Composites With Two-Scale Network Architecture, Yang Jiao, L. J. Huang, L. Geng 2016 Harbin Institute of Technology

Effects Of Sintering Parameters On The Microstructure And Tensile Properties Of In Situ (Ti5si3 + Tibw)/Ti6al4v Composites With Two-Scale Network Architecture, Yang Jiao, L. J. Huang, L. Geng

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.


Persistent Dopants And Phase Segregation In Organolead Mixed-Halide Perovskites, Bryan A. Rosales, Long Men, Sarah D. Cady, Michael P. Hanrahan, Aaron J. Rossini, Javier Vela 2016 Iowa State University

Persistent Dopants And Phase Segregation In Organolead Mixed-Halide Perovskites, Bryan A. Rosales, Long Men, Sarah D. Cady, Michael P. Hanrahan, Aaron J. Rossini, Javier Vela

Chemistry Publications

Organolead mixed-halide perovskites such as CH3NH3PbX3–aX′a (X, X′ = I, Br, Cl) are interesting semiconductors because of their low cost, high photovoltaic power conversion efficiencies, enhanced moisture stability, and band gap tunability. Using a combination of optical absorption spectroscopy, powder X-ray diffraction (XRD), and, for the first time, 207Pb solid state nuclear magnetic resonance (ssNMR), we probe the extent of alloying and phase segregation in these materials. Because 207Pb ssNMR chemical shifts are highly sensitive to local coordination and electronic structure, and vary linearly with halogen electronegativity and band gap, this technique can provide the true chemical speciation and ...


Effect Of Surface Treatment On Liquid Adhesion Inside 3-D Structures, Madani A. Khan, Jeffrey Alston, Andrew Guenthner, Jacob Zavala 2016 The City College of New York

Effect Of Surface Treatment On Liquid Adhesion Inside 3-D Structures, Madani A. Khan, Jeffrey Alston, Andrew Guenthner, Jacob Zavala

STAR (STEM Teacher and Researcher) Presentations

This study explores the relationship between chemical surface treatments on the interior of glass tubes and their resistance to fluid flow. By treating the interior of the tubes with functional silanes we can decrease or increase the interaction of the tube walls with the fluid column, which translates to changes in fluid column height for a given pressure differential. Resistance to fluid flow is quantified by using the tubes as integral parts of a barometric pressure column and measuring the changes in column height as the fluid is pulled into the tube by a set pressure differential. The barometric pressure ...


Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton 2016 Hope College

Dealloying Behavior Of Nico And Nicocu Thin Films, Benjamin Peecher, Jennifer R. Hampton

Faculty Publications

Porous metals and alloys, such as those fabricated via electrochemical dealloying, are of interest for a variety of energy applications, ranging from their potential for enhanced catalytic behavior to their use as high surface area supports for pseudocapacitor materials. Here, the electrochemical dealloying process was explored for electrodeposited binary NiCo and ternary NiCoCu thin films. For each of the four different metal ratios, films were dealloyed using linear sweep voltammetry to various potentials in order to gain insight into the evolution of the film over the course of the linear sweep. Electrochemical capacitance, scanning electron microscopy, and energy dispersive X-ray ...


Metal-Organic Hybrid Nanocomposites For Energy Harvesting Applications, Thulitha Madawa Abeywickrama 2016 Western Kentucky University

Metal-Organic Hybrid Nanocomposites For Energy Harvesting Applications, Thulitha Madawa Abeywickrama

Masters Theses & Specialist Projects

Various synthetic methods have been developed to produce metal nanostructures including copper and iron nanostructures. Modification of nanoparticle surface to enhance their characteristic properties through surface functionalization with organic ligands ranging from small molecules to polymeric materials including organic semiconducting polymers is a key interest in nanoscience. However, most of the synthetic methods developed in the past depend widely on non-aqueous solvents, toxic reducing agents, and high temperature and high-pressure conditions. Therefore, to produce metal nanostructures and their nanocomposites with a simpler and greener method is indeed necessary and desirable for their nano-scale applications. Hence the objective of this thesis ...


Photodynamic Killing Of Human Cancer Cells With Smart Photosensitizer Materials And An Endoscopic Implement For Singlet Oxygen Delivery, Mihaela N. Minnis 2016 The Graduate Center, City University of New York

Photodynamic Killing Of Human Cancer Cells With Smart Photosensitizer Materials And An Endoscopic Implement For Singlet Oxygen Delivery, Mihaela N. Minnis

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

The thesis describes progress on probe tips for a microoptic device for the precise delivery of the components necessary for photodynamic therapy (PDT) in a highly localized and controllable fashion. The thesis also summarizes results of a photosensitized oxidation study. The work focused on i) developing a photoactive fluoropolymer surface that will release sensitizer drug molecule for use in PDT, ii) designing new probe tips surfaces for use as sensitizer support for a microoptic PDT device, iii) exploring strategies for covalent attachment of sensitizers and model compounds to Teflon/PVA surfaces with the aim of being coupled with our microoptic ...


Probing The Structure And Photophysics Of Porphyrinoid Systems For Functional Materials, Christopher D. Farley 2016 The Graduate Center, City University of New York

Probing The Structure And Photophysics Of Porphyrinoid Systems For Functional Materials, Christopher D. Farley

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

Porphyrins (Pors) and their many cousins, including phthalocyanines (Pcs), corroles (Cors), subphthalocyanines (SubPcs), porphyrazines (Pzs), and naphthalocyanines (NPcs), play amazingly diverse roles in biological and non-biological systems because of their unique and tunable physical and chemical properties. These compounds, collectively known as porphyrinoids, can be employed in any number of functional devices that have the potential to address the challenges of modern society. Their incorporation into such devices, however, depends on many structural factors that must be well understood and carefully controlled in order to achieve the desired behavior. Self-assembly and self-organization are key processes for developing these new technologies ...


Large Scale Nanoparticle Screening For Small Molecule Analysis In Laser Desorption Ionization Mass Spectrometry, Gargey B. Yagnik, Rebecca L. Hansen, Andrew R. Korte, Malinda D. Reichert, Javier Vela, Young-Jin Lee 2016 Iowa State University

Large Scale Nanoparticle Screening For Small Molecule Analysis In Laser Desorption Ionization Mass Spectrometry, Gargey B. Yagnik, Rebecca L. Hansen, Andrew R. Korte, Malinda D. Reichert, Javier Vela, Young-Jin Lee

Chemistry Publications

Nanoparticles (NPs) have been suggested as efficient matrixes for small molecule profiling and imaging by laser-desorption ionization mass spectrometry (LDI-MS), but so far there has been no systematic study comparing different NPs in the analysis of various classes of small molecules. Here, we present a large scale screening of 13 NPs for the analysis of two dozen small metabolite molecules. Many NPs showed much higher LDI efficiency than organic matrixes in positive mode and some NPs showed comparable efficiencies for selected analytes in negative mode. Our results suggest that a thermally driven desorption process is a key factor for metal ...


Fabricating And Characterizing Chalcogenide Thin Films As Light Absorbing Layers In Solar Cells, Daniel Vaccarello 2016 The University of Western Ontario

Fabricating And Characterizing Chalcogenide Thin Films As Light Absorbing Layers In Solar Cells, Daniel Vaccarello

Electronic Thesis and Dissertation Repository

Solar cell development has been a focus in energy research, with light-absorbing layers as the key theme. Copper indium disulphide (CuInS2) and copper zinc tin sulphide (Cu2ZnSnS4 or CZTS) have energy band gaps that are optimal for solar energy conversion. New preparation methods have been developed with practicality, safety, and low costs in mind. The one-pot method developed in this thesis group has been utilized to create nanocrystals that can be used to absorb light and generate current. The use of low temperatures and minimalistic reaction conditions has led to the production of CIS and CZTS ...


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