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Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, Kyler Reser Knowles 2017 University of Southern Mississippi

Effect Of Chain Rigidity On Network Architecture And Deformation Behavior Of Glassy Polymer Networks, Kyler Reser Knowles

Dissertations

Processing carbon fiber composite laminates creates molecular-level strains in the thermoset matrix upon curing and cooling which can lead to failures such as geometry deformations, micro-cracking, and other issues. It is known strain creation is attributed to the significant volume and physical state changes undergone by the polymer matrix throughout the curing process, though storage and relaxation of cure-induced strains remain poorly understood. This dissertation establishes two approaches to address the issue. The first establishes testing methods to simultaneously measure key volumetric properties of a carbon fiber composite laminate and its polymer matrix. The second approach considers the rigidity of ...


A Ship-In-A-Bottle Strategy To Synthesize Encapsulated Intermetallic Nanoparticle Catalysts: Exemplified For Furfural Hydrogenation, Raghu V. Maligal-Ganesh, Chaoxian Xiao, Tian Wei Goh, Lin-Lin Wang, Jeffrey Gustafson, Yuchen Pei, Zhiyuan Qi, Duane D. Johnson, Shiran Zhang, Franklin Feng Tao, Wenyu Huang 2017 Iowa State University

A Ship-In-A-Bottle Strategy To Synthesize Encapsulated Intermetallic Nanoparticle Catalysts: Exemplified For Furfural Hydrogenation, Raghu V. Maligal-Ganesh, Chaoxian Xiao, Tian Wei Goh, Lin-Lin Wang, Jeffrey Gustafson, Yuchen Pei, Zhiyuan Qi, Duane D. Johnson, Shiran Zhang, Franklin Feng Tao, Wenyu Huang

Duane D. Johnson

Intermetallic compounds are garnering increasing attention as efficient catalysts for improved selectivity in chemical processes. Here, using a ship-in-a-bottle strategy, we synthesize single-phase platinum-based intermetallic nanoparticles (NPs) protected by a mesoporous silica (mSiO2) shell by heterogeneous reduction and nucleation of Sn, Pb, or Zn in mSiO2-encapsulated Pt NPs. For selective hydrogenation of furfural to furfuryl alcohol, a dramatic increase in activity and selectivity is observed when intermetallic NPs catalysts are used in comparison to Pt@mSiO2. Among the intermetallic NPs, PtSn@mSiO2 exhibits the best performance, requiring only one-tenth of the quantity of Pt used ...


Cytotoxic And Antimicrobial Effects Of Silver-Containing Surfaces, Sarah Goderecci 2017 Rowan University

Cytotoxic And Antimicrobial Effects Of Silver-Containing Surfaces, Sarah Goderecci

Theses and Dissertations

This study examines applications of sputtered silver coatings as alternatives to traditional antibiotic treatments. Given the increase in reports of antibiotic-resistant bacteria, new treatments and coatings for in-dwelling medical devices such as catheters and orthopedic implants are necessary. Silver oxide films were deposited onto Ti surfaces to examine the efficacy of such coatings against a variety of bacterial species both in vitro and in vivo. Bacterial growth studies showed that coatings exhibited antimicrobial activity against a range of bacterial species acting either in a bacteriostatic or bactericidal mechanism, depending on the target. Limited toxicity to in vitro mammalian cells was ...


Electrochemical And Modelling Studies On Simulated Spent Nuclear Fuel Corrosion Under Permanent Waste Disposal Conditions, Nazhen Liu 2017 The University of Western Ontario

Electrochemical And Modelling Studies On Simulated Spent Nuclear Fuel Corrosion Under Permanent Waste Disposal Conditions, Nazhen Liu

Electronic Thesis and Dissertation Repository

The safety assessment models for the deep geological disposal of spent nuclear fuel require a fundamental understanding of the corrosion of spent fuel in a failed waste container. The overall research goal of this project is to investigate the corrosion of simulated spent fuel under permanent disposal conditions, using both model simulations and experimental investigations. A model for fuel corrosion has been expanded to determine the relative importance of radiolytic hydrogen and hydrogen from corrosion of the steel vessel in suppressing fuel corrosion. It was shown that, for CANDU (CANada Deuterium Uranium) fuel with moderate in-reactor burnup, only micromolar concentrations ...


Two Homologous Intermetallic Phases In The Na–Au–Zn System With Sodium Bound In Unusual Paired Sites Within 1d Tunnels, Saroj L. Samal, Qisheng Lin, John D. Corbett 2017 Iowa State University

Two Homologous Intermetallic Phases In The Na–Au–Zn System With Sodium Bound In Unusual Paired Sites Within 1d Tunnels, Saroj L. Samal, Qisheng Lin, John D. Corbett

Qisheng Lin

The Na–Au–Zn system contains the two intermetallic phases Na0.97(4)Au2Zn4 (I) and Na0.72(4)Au2Zn2 (II) that are commensurately and incommensurately modulated derivatives of K0.37Cd2, respectively. Compound I crystallizes in tetragonal space group P4/mbm (No. 127), a = 7.986(1) Å, c = 7.971(1) Å, Z = 4, as a 1 × 1 × 3 superstructure derivative of K0.37Cd2 (I4/mcm). Compound II is a weakly incommensurate derivative of K0.37Cd2 with a modulation vector q = 0.189(1) along c. Its structure was solved in superspace group P4/mbm(00g)00ss, a = 7 ...


Superconducting Properties Of Rh 9 In 4 S 4 Single Crystals, Udhara S. Kaluarachchi, Qisheng Lin, Weiwei Xie, Valentin Taufour, S. L. Bud’ko, Gordon J. Miller, Paul C. Canfield 2017 Iowa State University

Superconducting Properties Of Rh 9 In 4 S 4 Single Crystals, Udhara S. Kaluarachchi, Qisheng Lin, Weiwei Xie, Valentin Taufour, S. L. Bud’Ko, Gordon J. Miller, Paul C. Canfield

Qisheng Lin

The synthesis and crystallographic, thermodynamic, and transport properties of single crystalline Rh9In4S4 were studied. The resistivity, magnetization, and specific heat measurements all clearly indicate bulk superconductivity with a critical temperature, Tc∼2.25 K. The Sommerfeld coefficient γ and the Debye temperature (ΘD) were found to be 34 mJ mol−1 K−2 and 217 K, respectively. The observed specific heat jump, ΔC/γTc=1.66, is larger than the expected BCS weak coupling value of 1.43. Ginzburg-Landau (GL) ratio of the low-temperature GL-penetration depth, λGL≈5750 Å, to the GL-coherence length, ξGL≈94 Å, is large: κ ∼60 ...


Synthesis, Structure, And Bonding Of Sc4mgxcu15-Xga~7.5 (X = 0, 0.5): Two Incommensurately Modulated Scandium Substitution Derivatives Of Cubic Mg2cu6ga5, Qisheng Lin, Sven Lidin, John D. Corbett 2017 The Ames Laboratory

Synthesis, Structure, And Bonding Of Sc4mgxcu15-Xga~7.5 (X = 0, 0.5): Two Incommensurately Modulated Scandium Substitution Derivatives Of Cubic Mg2cu6ga5, Qisheng Lin, Sven Lidin, John D. Corbett

Qisheng Lin

The substitution of scandium for magnesium in Mg2Cu6Ga5 (Mg2Zn11-type) yields an irrational superstructure phase that includes the refined compositions, Sc4Mg0.50(2)Cu14.50(2)Ga7.61(2) and Sc4Cu14.76(2)Ga7.51(2). These crystallize in Cmmm, a = ∼8.31 Å, b = ∼21.72 Å, c = ∼8.30 Å. The structures feature Sc2 dimers, Cu6 octahedra, a 3D CuGa (Cu12Ga2) framework, and arachno gallium-centered Cu4Ga6 icosahedra that are condensed into zigzag chains. The arrangement of these building blocks exhibits a topologic relationship to Mg2Cu6Ga5. Further studies reveal that the quaternary compound exhibits incommensurate modulations along a, with q ...


M3(Au,Ge)19 And M3.25(Au,Ge)18 (M = Ca, Yb): Distinctive Phase Separations Driven By Configurational Disorder In Cubic Ycd6-Type Derivatives, Qisheng Lin, John D. Corbett 2017 The Ames Laboratory

M3(Au,Ge)19 And M3.25(Au,Ge)18 (M = Ca, Yb): Distinctive Phase Separations Driven By Configurational Disorder In Cubic Ycd6-Type Derivatives, Qisheng Lin, John D. Corbett

Qisheng Lin

Exploratory syntheses in the M−Au−Ge (M = Ca, Yb) systems have led to the discovery of two cleanly separated non-stoichiometric phases M3Au∼14.4Ge∼4.6 (I) and M3.25Au∼12.7Ge∼5.3 (II). Single crystal X-ray studies reveal that both (space group Im3̅) feature body-centered-cubic packing of five-shell multiply endohedral clusters that resemble those in the parent YCd6 (= Y3Cd18) and are akin to approximate phases in other quasicrystal systems. However, differences resulting from various disorders in these are distinctive. The innermost cluster in the M3Au∼14.4Ge∼4.6 phase (I) remains a disordered tetrahedron, as ...


Li14.7mg36.8cu21.5ga66: An Intermetallic Representative Of A Type Iv Clathrate, Qisheng Lin, John D. Corbett 2017 The Ames Laboratory

Li14.7mg36.8cu21.5ga66: An Intermetallic Representative Of A Type Iv Clathrate, Qisheng Lin, John D. Corbett

Qisheng Lin

Synthetic explorations in the quaternary Li−Mg−Cu−Ga system yield the novel intermetallic Li14.7(8)Mg36.8(13)Cu21.5(5)Ga66 [P6̅m2, Z = 1, a = 14.0803(4) Å, c = 13.6252 (8) Å] from within a limited composition range. This contains a unique three-dimensional anionic framework consisting of distinct interbonded Ga12 icosahedra, dimerized Li@(Cu,Mg)10Ga6 icosioctahedra, and 15-vertex Li@(Cu,Mg)9Ga6 and Li@Cu3Ga12 polyhedra. These polyhedral clusters are hosted by M20 (512), M24 (51262), and M26 (51263) (M = Li/Mg) cages, respectively. The geometries and arrangements of these cages follow those ...


Multiple Nonstoichiometric Phases With Discrete Composition Ranges In The Caau5-Caau4bi-Biau2 System. A Case Study Of The Chemistry Of Spinodal Decomposition, Qisheng Lin, John D. Corbett 2017 The Ames Laboratory

Multiple Nonstoichiometric Phases With Discrete Composition Ranges In The Caau5-Caau4bi-Biau2 System. A Case Study Of The Chemistry Of Spinodal Decomposition, Qisheng Lin, John D. Corbett

Qisheng Lin

Synthetic explorations in the CaAu5−CaAu4Bi−BiAu2 system at 400 °C reveal five separate solid solution regions that show three distinct substitution patterns in the CaAu5 parent: (I) CaAu4(Au1−mBim) with 0 ≤ m ≤ 0.15(1), (II) 0.33(1) ≤ m ≤ 0.64(1), (III) 0.85(4) ≤ m ≤ 0.90(2); (IV) (Ca1−rAur)Au4(Bi1−sAus) with 0 ≤ r ≤ 0.39(1) and 0 ≤ s ≤ 0.12(2); (V) (Ca1−p−qAupBiq)Au4Bi with 0.09(2) ≤ p ≤ 0.13(1) and 0.31(2) ≤ q ≤ 0.72(4). Single crystal X-ray studies establish that all of ...


Formation Of Nets Of Corner-Shared Bicapped Gold Squares In Srau3ge: How A Baal4-Type Derivative Reconciles Fewer Valence Electrons And The Origin Of Its Uniaxial Negative Thermal Expansion, Qisheng Lin, John D. Corbett 2017 The Ames Laboratory

Formation Of Nets Of Corner-Shared Bicapped Gold Squares In Srau3ge: How A Baal4-Type Derivative Reconciles Fewer Valence Electrons And The Origin Of Its Uniaxial Negative Thermal Expansion, Qisheng Lin, John D. Corbett

Qisheng Lin

SrAu3Ge was synthesized by direct fusion of the mixed elements at high temperature followed by annealing treatments, and its structure was determined by single crystal X-ray diffraction means in space group (Pearson symbol: tP10) P4/nmm, a = 6.264(1) Å, c = 5.5082(9) Å, Z = 2 at room temperature. The structure of SrAu3Ge, a reapportioned √2 × √2 × 1 superstructure of CeMg2Si2(P4/mmm), exhibits checkerboard nets of corner-shared bicapped Au squares (or corner-shared Au(Au4/2)Ge octahedra), in which the apical Au–Ge pairs in adjoining nets are strongly interbonded in the c direction. This motif contrasts ...


Centric And Non-Centric Ca3au~7.5ge~3.5: Electron-Poor Derivatives Of La3al11. Syntheses, Structures, And Bonding Analyses, Qisheng Lin, John D. Corbett 2017 The Ames Laboratory

Centric And Non-Centric Ca3au~7.5ge~3.5: Electron-Poor Derivatives Of La3al11. Syntheses, Structures, And Bonding Analyses, Qisheng Lin, John D. Corbett

Qisheng Lin

Two La3Al11 type derivatives have been discovered in the Ca−Au−Ge system and structurally characterized by single-crystal X-ray diffraction. Compositions Ca3Au7.16(6)Ge3.84(6) (1) and Ca3Au7.43(9)Ge3.57(9) (2) lie within a non-centric Imm2 phase region with a ≈ 4.40 Å, b ≈ 13.06 Å, c ≈ 9.60 Å. The Au-richer and electron-poorer Ca3Au7.50(1)Ge3.50(1) (3) and Ca3Au8.01(1)Ge2.99(1)(4) occur within a centric Pnnm phase region with a ≈ 9.50 Å, b ≈ 13.20 Å, c ≈ 4.43 Å. Both phases contain complex ...


Exploratory Syntheses And Structures Of Srau4.3in1.7 And Caag3.5in1.9: Electron-Poor Intermetallics With Diversified Polyanionic Frameworks That Are Related To Ycd6-Type Quasicrystal, Qisheng Lin, John D. Corbett 2017 The Ames Laboratory

Exploratory Syntheses And Structures Of Srau4.3in1.7 And Caag3.5in1.9: Electron-Poor Intermetallics With Diversified Polyanionic Frameworks That Are Related To Ycd6-Type Quasicrystal, Qisheng Lin, John D. Corbett

Qisheng Lin

The phase regions around quasicrystals and approximants (QC/ACs) are rich pools for electron-poor intermetallics with novel, complex structures, and bonding patterns. The present SrAu4.30(1)In1.70(1) (1) and CaAg3.54(1)In1.88(1) (2) were synthesized through chemical tunings of the model CaAu4In2 (YCd6-Type) AC. Single crystal X-ray diffraction analyses reveals that crystal 1 has Pnma (CeCu6-type) symmetry, with a = 9.102(1) Å, b = 5.6379(9) Å, and c = 11.515(2) Å. The building block in 1 is a 19-vertex cluster Sr@Au9In4M6 (M = Au/In), which vividly mimics Ca@(Au,In ...


Gold Network Structures In Rhombohedral And Monoclinic Sr2au6(Au,T)3 (T= Zn, Ga). A Transition Via Relaxation, Trinath Mishra, Qisheng Lin, John D. Corbett 2017 Iowa State University

Gold Network Structures In Rhombohedral And Monoclinic Sr2au6(Au,T)3 (T= Zn, Ga). A Transition Via Relaxation, Trinath Mishra, Qisheng Lin, John D. Corbett

Qisheng Lin

Quantitative syntheses, structure determinations and interpretations, and band calculations are reported for the nonstoichiometric rhombohedral (Rc) and monoclinic (C2/c) Sr2Au6(Au3–xTx) (T = Zn, Ga) compounds. Several different compositions of the two Sr phases were similarly refined from single crystal X-ray diffraction data as Rc: a ≈ 8.43 Å, c ≈ 21.85 Å, Z = 6 and C2/c: a ≈ 14.70 Å, b ≈ 8.47 Å, c ≈ 8.70 Å, β ≈ 123.2°, Z = 4. The Rc Zn phase is stable in the composition region x ∼ 2.5–2 ...


Disorder–Order Structural Transformation In Electron-Poor Sr3au8sn3 Driven By Chemical Bonding Optimization, Qisheng Lin, Jordan Vetter, John D. Corbett 2017 The Ames Laboratory

Disorder–Order Structural Transformation In Electron-Poor Sr3au8sn3 Driven By Chemical Bonding Optimization, Qisheng Lin, Jordan Vetter, John D. Corbett

Qisheng Lin

Sr3Au8Sn3 was synthesized through fusion of a stoichiometric amount of pure metals at 800 °C and annealing treatments at lower temperatures. Single-crystal X-ray diffraction analyses revealed that Sr3Au8Sn3 has a La3Al11-type Immm structure (a = 4.6767(8) Å, b = 9.646(2) Å, c = 14.170(2) Å, Z = 2) if annealed at 550 °C and above but a Ca3Au8Ge3-type structure (Pnnm, a = 9.6082(8) Å, b = 14.171(1) Å, c = 4.6719(4) Å, Z = 2) if annealed at 400 °C. The transition occurs at about 454 °C according to DTA data. Both structures feature columns of ...


Design Of Collagen-Mimetic Peptides, Parminder Jeet Kaur 2017 The Graduate Center, City University of New York

Design Of Collagen-Mimetic Peptides, Parminder Jeet Kaur

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

Collagen is the major component of the extracellular matrix and is involved in a wide range of cellular functions during tissue development and action. At the core of the diverse functions of this versatile protein is its remarkable ability to form supramolecular structures through self-assembly and/or through interactions with other biomolecules. One typical example of such supramolecular structure is the fibrils of collagen types I, II and III of the connective tissues. These fibrils have staggered arrangement of the laterally associated collagen triple helices – the structural unit of collagen – to form long, smooth fibrils with a characteristic 67 nm ...


Energetic Effects Of Hole Transporting Materials On The Performance Of Organometal Halide Perovskite Photovoltaic Cells, So Min Park 2017 University of Kentucky

Energetic Effects Of Hole Transporting Materials On The Performance Of Organometal Halide Perovskite Photovoltaic Cells, So Min Park

Theses and Dissertations--Chemistry

Efficient, inexpensive, lightweight and flexible solar cells are desired to help meet the world’s growing energy needs. Organometal halide perovskite (OMHP) photovoltaic (PV) cells have shown dramatic increases in solar cell efficiencies increase over the last 5 years. OMHP PV cells have attracted significant attention due to their broad absorption spectra, high electron and hole mobility, and low production cost. The interface between hole transporting layer (HTL) and perovskite thin films have a significant influence on charge transfer and overall solar cell performance. 2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenylamine)9,9’-spirobifluorene (Spiro-OMeTAD) is a small molecule largely ...


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 ...


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