Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Physics
Quantifying Temperature-, Pressure-, And Nuclear Quantum Effects On Hydrophobic And Hydrophilic Water-Mediated Interactions, Justin T. Engstler
Quantifying Temperature-, Pressure-, And Nuclear Quantum Effects On Hydrophobic And Hydrophilic Water-Mediated Interactions, Justin T. Engstler
Dissertations, Theses, and Capstone Projects
Water-mediated interactions (WMIs) are responsible for diverse processes in aqueous solutions, including protein folding and nanoparticle aggregation. WMI may be affected by changes in temperature and pressure, and hence, they can alter chemical/physical processes that occur in aqueous environments. Traditionally, attention has been focused on hydrophobic interactions while, in comparison, the role of hydrophilic and hybrid (hydrophobic–hydrophilic) interactions have been mostly overlooked. Here, we study the role of T and P on the WMI between nanoscale (i) hydrophobic–hydrophobic, (ii) hydrophilic–hydrophilic, and (iii) hydrophilic–hydrophobic pairs of (hydroxylated/non-hydroxylated) graphene-based surfaces. We find that hydrophobic, hydrophilic, and hybrid interactions are all sensitive to …
Computational Modeling Of Charge And Excitation Energy Transfer Dynamics In Complex Environments, Ning Chen
Computational Modeling Of Charge And Excitation Energy Transfer Dynamics In Complex Environments, Ning Chen
Dissertations, Theses, and Capstone Projects
This thesis describes computational simulations of charge and exciton dynamics and quantum calculations of organic conjugated oligomers. A comprehensive computational study of charge hopping dynamics was conducted for a model of disordered chain of sites coupled to quantum environments. Time-dependent mean square displacement, diffusion constant, and mobility were calculated by three different computational methods for solving the master equation, which validate the accuracy of calculations. Approximate rate kernels were also tested to understand the effects of approximations in representing quantum environments. In addition to the effects of temperature and disorder, different values of the gradient in the site energy were …
Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar
Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar
Dissertations, Theses, and Capstone Projects
Energy storage and conversion plays a critical role in the efficient use of available energy and is crucial for the utilization of renewable energy sources. To achieve maximum efficiency of renewable energy sources, improvements to energy storage materials must be developed. In this work, novel electrolytes for secondary batteries and fuel cells have been studied using nuclear magnetic resonance and high pressure x-ray scattering techniques to form a better understanding of dynamic and structural properties of these materials. Ionic liquids have been studied due to their potential as a safer alternative to organic solvent-based electrolytes in lithium-ion batteries and composite …
Wigner High-Electron-Correlation Regime Of Non-Uniform Density Systems: A Quantal-Density-Functional-Theory Study, Douglas Mortimer Achan
Wigner High-Electron-Correlation Regime Of Non-Uniform Density Systems: A Quantal-Density-Functional-Theory Study, Douglas Mortimer Achan
Dissertations, Theses, and Capstone Projects
The Wigner regime of a system of electrons in an external field is characterized by a low electron density and a high electron-interaction energy relative to the kinetic energy. The low correlation regime is in turn described by a high electron density and an electron-interaction energy smaller than the kinetic energy. The Wigner regime of a nonuniform electron density system is investigated via quantal density functional theory (QDFT). Within QDFT, the contributions of electron correlations due to the Pauli exclusion principle, Coulomb repulsion, and correlation-kinetic effects are separately delineated and explicitly defined. The nonuniform electron density system studied is that …
Variable Pressure Nuclear Magnetic Resonance Studies Of Ionic Liquids And Electrophoretic Probe Design, Armando Julio Rua
Variable Pressure Nuclear Magnetic Resonance Studies Of Ionic Liquids And Electrophoretic Probe Design, Armando Julio Rua
Dissertations, Theses, and Capstone Projects
Energy storage materials play a key role in, efficient, clean, and versatile use of energy, and are crucial for the exploitation of renewable energy. The improve efficiency of energy use stimulates the development of energy storage such as batteries or super capacitors, toward higher power and energy density, which significantly depends upon the advancement of new materials used in these devices. The new materials need better understanding and description in the electrochemical properties. Nuclear Magnetic Resonance (NMR) has been an important tool in the characterization of ionic liquids and solids. The measurements of the relaxation times and the diffusion coefficient …