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Northeastern University
1.
Halu, Arda.
Dynamics of and on complex networks.
Degree: PhD, Department of Physics, 2014, Northeastern University
URL: http://hdl.handle.net/2047/d20004937
► Complex networks are dynamic, evolving structures that can host a great number of dynamical processes. In this thesis, we address current challenges regarding the dynamics…
(more)
▼ Complex networks are dynamic, evolving structures that can host a great number of dynamical processes. In this thesis, we address current challenges regarding the dynamics of and dynamical processes on complex networks. First, we study complex network dynamics from the standpoint of network growth. As a quantitative measure of the complexity and information content of networks generated by growing network models, we define and evaluate their entropy rate. We propose stochastic growth models inspired by the duplication-divergence mechanism to generate epistatic interaction networks and find that they exhibit the property of monochromaticity as a result of their dynamical evolution. Second, we explore the dynamics of quantum mechanical processes on complex networks. We investigate the Bose-Hubbard model on annealed and quenched scale-free networks as well as Apollonian networks and show that their phase diagram changes significantly in the presence of complex topologies, depending on the second degree of the degree distribution and the maximal eigenvalue of the adjacency matrix. We then study the Jaynes-Cummings-Hubbard model on various complex topologies and demonstrate the importance of the maximal eigenvalue of the hopping matrix in determining the phase diagram of the model. Third, we investigate dynamical processes on interacting and multiplex networks. We study opinion dynamics in a simulated setting of two antagonistically interacting networks and recover the importance of connectivity and committed agents. We propose a multiplex centrality measure that takes into account the connectivity patterns within and across different layers and find that the dynamics of biased random walks on multiplex networks gives rise to a centrality ranking that is different from univariate centrality measures. Finally, we study the statistical mechanics of multilayered spatial networks and demonstrate the emergence of significant link overlap and improved navigability in multiplex and interacting spatial networks.
Subjects/Keywords: Network Science; Statistical Physics; Physics; Statistical, Nonlinear, and Soft Matter Physics
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APA (6th Edition):
Halu, A. (2014). Dynamics of and on complex networks. (Doctoral Dissertation). Northeastern University. Retrieved from http://hdl.handle.net/2047/d20004937
Chicago Manual of Style (16th Edition):
Halu, Arda. “Dynamics of and on complex networks.” 2014. Doctoral Dissertation, Northeastern University. Accessed March 07, 2021.
http://hdl.handle.net/2047/d20004937.
MLA Handbook (7th Edition):
Halu, Arda. “Dynamics of and on complex networks.” 2014. Web. 07 Mar 2021.
Vancouver:
Halu A. Dynamics of and on complex networks. [Internet] [Doctoral dissertation]. Northeastern University; 2014. [cited 2021 Mar 07].
Available from: http://hdl.handle.net/2047/d20004937.
Council of Science Editors:
Halu A. Dynamics of and on complex networks. [Doctoral Dissertation]. Northeastern University; 2014. Available from: http://hdl.handle.net/2047/d20004937

University of New Mexico
2.
Chase, Matthew.
Memory Effects in Brownian Motion, Random Walks under Confining Potentials, and Relaxation of Quantum Systems.
Degree: Physics & Astronomy, 2016, University of New Mexico
URL: https://digitalrepository.unm.edu/phyc_etds/106
► This dissertation is a report on a number of distinct topics in the field of non-equilibrium statistical mechanics including the evolution of classical as…
(more)
▼ This dissertation is a report on a number of distinct topics in the field of non-equilibrium
statistical mechanics including the evolution of classical as well as quantum systems.
The evolution of an object that is described by the Ornstein-Uhlenbeck process generalized through a time-nonlocal attraction is considered. The time-nonlocality is taken to be represented in the Langevin description through the presence of memory. Analysis of the Langevin equation is performed for algebraic and delay-type memories. An equivalent \emph{bona-fide} Fokker-Planck equation is constructed.
A random walker subjected to a non-standard confining potential, taken to be a piece-wise linear function, is analyzed. Matching conditions for arbitrary joining configurations are given. Exact propagators in both the time- and Laplace-domains are derived for the case of a `V'-shaped potential. Two illustrative applications of such calculations are presented in the areas of chemical
physics and biophysics.
The relaxation of quantum systems interacting with a thermal reservoir is studied. Calculations for specified bath spectral functions are presented. Our primary focus is the vibrational relaxation of an excited molecule and we provide a generalization of the Montroll-Shuler equation into the coherent domain. A related system, the Stark ladder, is briefly discussed.
Advisors/Committee Members: Vasudev Kenkre, Sudhakar Prasad, Dinesh Loomba, Luca Giuggioli.
Subjects/Keywords: Astrophysics and Astronomy; Physics; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
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MLA ·
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APA (6th Edition):
Chase, M. (2016). Memory Effects in Brownian Motion, Random Walks under Confining Potentials, and Relaxation of Quantum Systems. (Doctoral Dissertation). University of New Mexico. Retrieved from https://digitalrepository.unm.edu/phyc_etds/106
Chicago Manual of Style (16th Edition):
Chase, Matthew. “Memory Effects in Brownian Motion, Random Walks under Confining Potentials, and Relaxation of Quantum Systems.” 2016. Doctoral Dissertation, University of New Mexico. Accessed March 07, 2021.
https://digitalrepository.unm.edu/phyc_etds/106.
MLA Handbook (7th Edition):
Chase, Matthew. “Memory Effects in Brownian Motion, Random Walks under Confining Potentials, and Relaxation of Quantum Systems.” 2016. Web. 07 Mar 2021.
Vancouver:
Chase M. Memory Effects in Brownian Motion, Random Walks under Confining Potentials, and Relaxation of Quantum Systems. [Internet] [Doctoral dissertation]. University of New Mexico; 2016. [cited 2021 Mar 07].
Available from: https://digitalrepository.unm.edu/phyc_etds/106.
Council of Science Editors:
Chase M. Memory Effects in Brownian Motion, Random Walks under Confining Potentials, and Relaxation of Quantum Systems. [Doctoral Dissertation]. University of New Mexico; 2016. Available from: https://digitalrepository.unm.edu/phyc_etds/106

University of Tennessee – Knoxville
3.
Holt, Adam Prillaman.
The Effect of Attractive Polymer-Nanoparticle Interactions on the Local Segmental Dynamics of Polymer Nanocomposites.
Degree: 2016, University of Tennessee – Knoxville
URL: https://trace.tennessee.edu/utk_graddiss/3862
► Considerable progress has been made in understanding the miscibility and morphology of polymer nanocomposites (PNCs). However, to date, there is little understood concerning the modification…
(more)
▼ Considerable progress has been made in understanding the miscibility and morphology of polymer nanocomposites (PNCs). However, to date, there is little understood concerning the modification of segmental mobility at the polymer-nanoparticle interface, which due to prevalence of interfaces in PNCs, will predominately control the viscoelastic and mechanical properties of these materials.
In this dissertation, static and dynamic experimental techniques are combined to identify the specific parameters controlling the modification of segmental dynamics at the polymer-nanoparticle interface in the model system of poly(2-vinyl pyridine)/silica nanocomposites. In general, the experimental results clearly demonstrate that the segmental dynamics at the polymer-nanoparticle interface are suppressed relative to the bulk-like polymer and moreover that this effect is dependent on the molecular weight (MW) of the polymer matrix. Additionally, the density of the polymer-nanoparticle interface was found to unexpectedly decrease with increasing MW. These unexpected results indicate a competition between a suppression due to adsorption and a speeding up due to the reduction in density – which suggests that the chain packing at the polymer-nanoparticle interface becomes frustrated at higher MWs. Lastly, by comparing the strength of the polymer-nanoparticle interaction and molecular weight, it is proposed that the orientational anisotropy of the chain conformations primarily controls the magnitude of the dynamic suppression at the polymer-nanoparticle interface and suggests a new way to tailor the segmental dynamics on the nanoscale.
Subjects/Keywords: polymers; polymer nanocomposites; glass transition; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Holt, A. P. (2016). The Effect of Attractive Polymer-Nanoparticle Interactions on the Local Segmental Dynamics of Polymer Nanocomposites. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/3862
Chicago Manual of Style (16th Edition):
Holt, Adam Prillaman. “The Effect of Attractive Polymer-Nanoparticle Interactions on the Local Segmental Dynamics of Polymer Nanocomposites.” 2016. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed March 07, 2021.
https://trace.tennessee.edu/utk_graddiss/3862.
MLA Handbook (7th Edition):
Holt, Adam Prillaman. “The Effect of Attractive Polymer-Nanoparticle Interactions on the Local Segmental Dynamics of Polymer Nanocomposites.” 2016. Web. 07 Mar 2021.
Vancouver:
Holt AP. The Effect of Attractive Polymer-Nanoparticle Interactions on the Local Segmental Dynamics of Polymer Nanocomposites. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2016. [cited 2021 Mar 07].
Available from: https://trace.tennessee.edu/utk_graddiss/3862.
Council of Science Editors:
Holt AP. The Effect of Attractive Polymer-Nanoparticle Interactions on the Local Segmental Dynamics of Polymer Nanocomposites. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2016. Available from: https://trace.tennessee.edu/utk_graddiss/3862

Boise State University
4.
Henry, Michael Montgomery.
Useable Coarse-Grained Models for Semiconducting Polymers and Thermosets.
Degree: 2020, Boise State University
URL: https://scholarworks.boisestate.edu/td/1760
► This work aims to inform the formulation and processing of polymer mixtures through the use of models that have minimally sufficient complexity. Models with minimal…
(more)
▼ This work aims to inform the formulation and processing of polymer mixtures through the use of models that have minimally sufficient complexity. Models with minimal complexity are easier to develop, understand, explain, and extend, all of which underpin model validation, verification, and reproducibility.
We develop simplified models for two different material systems, semiconducting polymers and thermosets. With the relatively low cost of predicting morphologies enabled by these models, we investigate structure-property-processing relationships in record system sizes and combinatorial parameter spaces. The insight from these models lays the foundation for improving the efficiency of organic solar cells and air travel.
The morphology of the active layer of an organic solar cell determines its efficiency, but is also the most difficult aspect to control during manufacturing. Morphology can in principle be controlled through the thermodynamic self-assembly of active layer components. We develop models of two semiconducting polymers. We find our predictions are validated by morphological and charge transport measurements from experiments and we provide guidance for optimizing conditions for self-assembly.
Thermoset polymers present a unique modeling challenge because their properties are sensitive to processing kinetics that are at odds with thermodynamic modeling frameworks. The primary source of this difficulty is bridging time (1×10−12s) and length scales (1×10−10m) of reaction dynamics with the time (1×102s) and length scales (1×10−6m) of morphology evolution. We implement a coarse-grained model of toughened thermosets where each amine, epoxy, and toughener mer is treated as a single simulation element. This simplification allows us to reach the time and length scales necessary to model the epoxy amine reaction and observe curing-driven morphology evolution. We simulate curing of (100 nm)3, million-particle volumes, which allows observation of experimentally-relevant volume evolution.
To practice behaviors necessary for computational research to be usable and reproduced by others, we make available all the models, initial configurations, submission scripts, analysis scripts, and simulation data associated with this work with an opensource, permissive license. We describe software development practices and design choices that make this possible and discuss opportunities for improvement in future computational materials research.
Subjects/Keywords: material science; self-assembly; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
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CSE |
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APA (6th Edition):
Henry, M. M. (2020). Useable Coarse-Grained Models for Semiconducting Polymers and Thermosets. (Thesis). Boise State University. Retrieved from https://scholarworks.boisestate.edu/td/1760
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Henry, Michael Montgomery. “Useable Coarse-Grained Models for Semiconducting Polymers and Thermosets.” 2020. Thesis, Boise State University. Accessed March 07, 2021.
https://scholarworks.boisestate.edu/td/1760.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Henry, Michael Montgomery. “Useable Coarse-Grained Models for Semiconducting Polymers and Thermosets.” 2020. Web. 07 Mar 2021.
Vancouver:
Henry MM. Useable Coarse-Grained Models for Semiconducting Polymers and Thermosets. [Internet] [Thesis]. Boise State University; 2020. [cited 2021 Mar 07].
Available from: https://scholarworks.boisestate.edu/td/1760.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Henry MM. Useable Coarse-Grained Models for Semiconducting Polymers and Thermosets. [Thesis]. Boise State University; 2020. Available from: https://scholarworks.boisestate.edu/td/1760
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Western Ontario
5.
Changizrezaei, Setarehalsadat.
Simulation of Heterogeneous Colloidal Particles Immersed in Liquid Crystals.
Degree: 2016, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/3670
► This thesis describes an investigation of interactions between colloidal particles immersed in a liquid crystal. The presence of colloidal particles in the liquid crystal distorts…
(more)
▼ This thesis describes an investigation of interactions between colloidal particles immersed in a liquid crystal. The presence of colloidal particles in the liquid crystal distorts the director field distorted from its uniform orientation. These elastic distortions produce topological defects around the particles, which induce anisotropic interactions between them, and these anisotropic interactions can be used to manufacture non-closed packed colloidal crystals, such as diamond lattices, which are interesting in photonic applications. First, different types of liquid crystals, the mathematical tools to describe the anisotropic nature of liquid crystals, the Landau-de Gennes free-energy model to investigate the particle’s interaction, and different kinds of topological defects are described. Moreover, previous work regarding the interaction of particles with the same applied boundary conditions in both nematic and cholesteric liquid crystal are discussed. Second, the lattice Boltzmann method is introduced in order to couple the molecular dynamics particles to the computational fluid mesh, and the simulation is performed in the open source molecular dynamics package, LAMMPS. Next, we explore anisotropic interactions with minima at specific orientations of particles with heterogeneous boundary conditions inside both nematic and cholesteric liquid crystals, which have not been observed so far. The results show that when particles are put at different distances and angles with respect to each other, new types of defect structures are produced, depending on the relative distances and directions. In the cholesteric liquid crystal, the value of pitch affects the defect structures and induced forces.
Subjects/Keywords: Liquid Crystal; Lattice Boltzmann; Condensed Matter Physics; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
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to Zotero / EndNote / Reference
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APA (6th Edition):
Changizrezaei, S. (2016). Simulation of Heterogeneous Colloidal Particles Immersed in Liquid Crystals. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/3670
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Changizrezaei, Setarehalsadat. “Simulation of Heterogeneous Colloidal Particles Immersed in Liquid Crystals.” 2016. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/3670.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Changizrezaei, Setarehalsadat. “Simulation of Heterogeneous Colloidal Particles Immersed in Liquid Crystals.” 2016. Web. 07 Mar 2021.
Vancouver:
Changizrezaei S. Simulation of Heterogeneous Colloidal Particles Immersed in Liquid Crystals. [Internet] [Thesis]. University of Western Ontario; 2016. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/3670.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Changizrezaei S. Simulation of Heterogeneous Colloidal Particles Immersed in Liquid Crystals. [Thesis]. University of Western Ontario; 2016. Available from: https://ir.lib.uwo.ca/etd/3670
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Embry-Riddle Aeronautical University
6.
Kitchen-McKinley, Samuel J.
Variable Structure Feedback Control with Application to Spacecraft with Small Thrust Propulsion Systems.
Degree: PhD, Physical Sciences, 2017, Embry-Riddle Aeronautical University
URL: https://commons.erau.edu/edt/357
► Small spacecrafts requiring small propulsion systems are becoming more popular for low Earth orbit. It is important for these research satellites to have accurate…
(more)
▼ Small spacecrafts requiring small propulsion systems are becoming more popular for low Earth orbit. It is important for these research satellites to have accurate guidance and control systems. Small propulsion systems will also be beneficial for multiple small spacecrafts used future exploration expeditions beyond low Earth orbit. These small spacecrafts benefit from the simplicity of low thrust cold gas propulsion systems. Additionally, large spacecrafts using low thrust, high specific impulse propellants for main propulsion systems, such as ion engines, allow longer and more flexible missions, including Earth orbiting spacecraft and interplanetary spacecraft.
In order to extend the life of future planetary exploration missions, it becomes necessary to use In-Situ Resource Utilization (ISRU) to be able to extract resources such as water, oxygen, propellants, and building materials from the local target environment. Small free flying vehicles can be used for quickly surveying planetary surfaces in order to search for potential resource locations. These surveying vehicles can also use such extracted propellants if their propulsion system is designed for it. Cold gas propulsion provides a flexible system to use locally extracted or manufactured propellants.
This dissertation investigates nonlinear feedback control techniques for spacecraft with low thrust, cold gas thrust, and spacecraft with cold gas thrust. A model for a cold gas propulsion system is developed for designing control systems for multiple types cold gas thrusters. The model is also used for testing control algorithms in simulation. The cold gas model is validated from a cold gas propulsion hardware testing, and a control law is tested on hardware.
Subjects/Keywords: Aerospace Engineering; Engineering Physics; Propulsion and Power; Space Vehicles; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
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APA (6th Edition):
Kitchen-McKinley, S. J. (2017). Variable Structure Feedback Control with Application to Spacecraft with Small Thrust Propulsion Systems. (Doctoral Dissertation). Embry-Riddle Aeronautical University. Retrieved from https://commons.erau.edu/edt/357
Chicago Manual of Style (16th Edition):
Kitchen-McKinley, Samuel J. “Variable Structure Feedback Control with Application to Spacecraft with Small Thrust Propulsion Systems.” 2017. Doctoral Dissertation, Embry-Riddle Aeronautical University. Accessed March 07, 2021.
https://commons.erau.edu/edt/357.
MLA Handbook (7th Edition):
Kitchen-McKinley, Samuel J. “Variable Structure Feedback Control with Application to Spacecraft with Small Thrust Propulsion Systems.” 2017. Web. 07 Mar 2021.
Vancouver:
Kitchen-McKinley SJ. Variable Structure Feedback Control with Application to Spacecraft with Small Thrust Propulsion Systems. [Internet] [Doctoral dissertation]. Embry-Riddle Aeronautical University; 2017. [cited 2021 Mar 07].
Available from: https://commons.erau.edu/edt/357.
Council of Science Editors:
Kitchen-McKinley SJ. Variable Structure Feedback Control with Application to Spacecraft with Small Thrust Propulsion Systems. [Doctoral Dissertation]. Embry-Riddle Aeronautical University; 2017. Available from: https://commons.erau.edu/edt/357

University of Western Ontario
7.
Hopkins, Cameron C.
Vibrating-wire Rheometry.
Degree: 2018, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/5584
► This thesis consists of two projects on the behaviour of a novel vibrating-wire rheometer and a third project studying the gelation dynamics of aqueous solutions…
(more)
▼ This thesis consists of two projects on the behaviour of a novel vibrating-wire rheometer and a third project studying the gelation dynamics of aqueous solutions of Pluronic F127. In the first study, we use COMSOL to perform two-dimensional simulations of the oscillations of a wire in Newtonian and shear-thinning fluids. Our results show that the resonant behaviour of the wire agrees well with the theory of a wire vibrating in Newtonian fluids. In shear-thinning fluids, we find resonant behaviour similar to that in Newtonian fluids. In addition, we find that the shear-rate and viscosity in the fluid vary significantly in both space and time. We find that the resonant behaviour of the wire can be well described by the theory of a wire vibrating in a Newtonian fluid if the viscosity in the theory is set equal to the viscosity averaged over the circumference of the wire and over one period of the wire’s oscillation at the resonant frequency. In the second study, we present the design and operation of our vibrating-wire rheometer and use it to measure the properties of Newtonian and viscoelastic fluids. We find that our device can accurately measure small viscosities. In homogeneous polymer solutions, we find that the viscoelastic moduli measured using our device are consistent with measurements at lower frequencies using a shear rheometer. In addition, we find that our device can measure the microrheological properties of an aging Laponite clay suspension that is heterogeneous on the micron scale. In the third project, we study the gelation dynamics of aqueous solutions of Pluronic F127. Using shear rheometry we find that when slowly heating the solutions, they undergo a transition from sol to gel around room temperature, followed by a gel to sol transition at a higher temperature. Our results show that these transitions take place over a temperature range of a few degrees. When cooling the solutions, the reverse transitions occur over a larger range of temperature and the width in temperature of the gel phase is larger. At temperatures near the phase transitions, we find that the rheological relaxation time becomes very long.
Subjects/Keywords: Rheology; rheometry; viscometry; vibrating wire; complex fluids; Pluronic; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Hopkins, C. C. (2018). Vibrating-wire Rheometry. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/5584
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Hopkins, Cameron C. “Vibrating-wire Rheometry.” 2018. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/5584.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hopkins, Cameron C. “Vibrating-wire Rheometry.” 2018. Web. 07 Mar 2021.
Vancouver:
Hopkins CC. Vibrating-wire Rheometry. [Internet] [Thesis]. University of Western Ontario; 2018. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/5584.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hopkins CC. Vibrating-wire Rheometry. [Thesis]. University of Western Ontario; 2018. Available from: https://ir.lib.uwo.ca/etd/5584
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Michigan Technological University
8.
Shock, Cameron John.
The Solvation Energy of Ions in a Stockmayer Fluid.
Degree: MS, Department of Physics, 2019, Michigan Technological University
URL: https://digitalcommons.mtu.edu/etdr/885
► The solvation of ions in polar solvents has been a long studied system since the early twentieth century. A common technique to calculate the…
(more)
▼ The solvation of ions in polar solvents has been a long studied system since the early twentieth century. A common technique to calculate the energy associated with ion solvation is the Born Solvation energy equation. This equation assumes an ion is placed in an incompressible, homogeneous dielectric, which is not necessarily representative of a real system. In this work the Stockmayer Fluid Model is used in a molecular dynamics simulation through the software LAMMPS to check the quantitative correctness of the Born equation. It is also shown how solvation energies of ions placed in polymerized and non-polymerized solvents differ. It is shown that solvation energies in non-polymerized solvents are less negative than the predicted Born Solvation energy due to dielectric saturation effects, but are qualitatively similar. Solvation energies of polymerized solvents differ greatly from non-polymerized solvents and the predicted Born Solvation Energy. The reason for this is speculated to be due to compressibility of the solvents or structural and dipolar effects from polymer chains. It is also shown that the Stockmayer Fluid Model can be used to accurately predict experimental results for non-polymeric solvents.
Advisors/Committee Members: Issei Nakamura.
Subjects/Keywords: polymer; orientational polarization; electronic polarization; Onsager; Debye; dipole; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Shock, C. J. (2019). The Solvation Energy of Ions in a Stockmayer Fluid. (Masters Thesis). Michigan Technological University. Retrieved from https://digitalcommons.mtu.edu/etdr/885
Chicago Manual of Style (16th Edition):
Shock, Cameron John. “The Solvation Energy of Ions in a Stockmayer Fluid.” 2019. Masters Thesis, Michigan Technological University. Accessed March 07, 2021.
https://digitalcommons.mtu.edu/etdr/885.
MLA Handbook (7th Edition):
Shock, Cameron John. “The Solvation Energy of Ions in a Stockmayer Fluid.” 2019. Web. 07 Mar 2021.
Vancouver:
Shock CJ. The Solvation Energy of Ions in a Stockmayer Fluid. [Internet] [Masters thesis]. Michigan Technological University; 2019. [cited 2021 Mar 07].
Available from: https://digitalcommons.mtu.edu/etdr/885.
Council of Science Editors:
Shock CJ. The Solvation Energy of Ions in a Stockmayer Fluid. [Masters Thesis]. Michigan Technological University; 2019. Available from: https://digitalcommons.mtu.edu/etdr/885

Virginia Commonwealth University
9.
Ojaghlou, Neda.
Adhesion at Solid/Liquid Interfaces.
Degree: PhD, Chemistry, 2019, Virginia Commonwealth University
URL: https://doi.org/10.25772/PZM6-S872
;
https://scholarscompass.vcu.edu/etd/6079
► The adhesion at solid/liquid interface plays a fundamental role in diverse fields and helps explain the structure and physical properties of interfaces, at the…
(more)
▼ The adhesion at solid/liquid interface plays a fundamental role in diverse fields and helps explain the structure and physical properties of interfaces, at the atomic scale, for example in catalysis, crystal growth, lubrication, electrochemistry, colloidal system, and in many biological reactions. Unraveling the atomic structure at the solid/liquid interface is, therefore, one of the major challenges facing the surface science today to understand the physical processes in the phenomena such as surface coating, self-cleaning, and oil recovery applications. In this thesis, a variety of theory/computational methods in
statistical physics and
statistical mechanics are used to improve understanding of water adhesion at solid/liquid interfaces. In here, we addressed two separated, but interconnected problems:
First, we consider water adhesion on fiber/surface, responsible for the emergence of droplet residue upon droplet detachment. In this project, we study the mechanism of water droplet detachment and retention of residual water on smooth hydrophilic fibers and surfaces using nonequilibrium molecular dynamics simulations. We investigate how the applied force affects the breakup of a droplet and how the minimal detaching force per unit mass decreases with droplet size. We extract scaling relations that allow extrapolation of our findings to larger length scales that are not directly accessible by molecular models. We find that the volume of the residue on a fiber varies nonmonotonically with the detaching force, reaching the maximal size at an intermediate force and associated detachment time. The strength of this force decreases with the size of the drop, while the maximal residue increases with the droplet volume,
V, sub-linearly, in proportion to the V
2/3.
Second, we address the adhesion on conducting graphene. We improved the graphene model by incorporating the conductivity of graphene sheet using the fluctuating charge technique of Constant Potential Molecular Dynamics (CPMD). We evaluated the wettability by measuring the contact angle of cylindrical water drops on a conducting graphene sheet. We found that the CA of a water droplet on a graphene sheet supported by water is lower than in the absence of water under graphene. Our calculations reveal effective attractions between partial charges of equal sign across the conducting graphene sheet. Attractive correlations are attributed to the formation of the highly localized image charges on carbon atoms between the partially charged sites of water molecules on both sides of graphene. By performing additional computations with nonpolar diiodomethane, we confirm that graphene transmits both polar and dispersive interactions. These findings are important in applications including sensors, fuel cell membranes, water filtration, and graphene-based electrode material to enhance the supercapacitor performance. A challenge for future work concerns dynamic polarization response of wetted graphene at alternating (AC) field condition.
Advisors/Committee Members: Neda Ojaghlou.
Subjects/Keywords: Computational Engineering; Fluid Dynamics; Physical Chemistry; Statistical, Nonlinear, and Soft Matter Physics
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APA (6th Edition):
Ojaghlou, N. (2019). Adhesion at Solid/Liquid Interfaces. (Doctoral Dissertation). Virginia Commonwealth University. Retrieved from https://doi.org/10.25772/PZM6-S872 ; https://scholarscompass.vcu.edu/etd/6079
Chicago Manual of Style (16th Edition):
Ojaghlou, Neda. “Adhesion at Solid/Liquid Interfaces.” 2019. Doctoral Dissertation, Virginia Commonwealth University. Accessed March 07, 2021.
https://doi.org/10.25772/PZM6-S872 ; https://scholarscompass.vcu.edu/etd/6079.
MLA Handbook (7th Edition):
Ojaghlou, Neda. “Adhesion at Solid/Liquid Interfaces.” 2019. Web. 07 Mar 2021.
Vancouver:
Ojaghlou N. Adhesion at Solid/Liquid Interfaces. [Internet] [Doctoral dissertation]. Virginia Commonwealth University; 2019. [cited 2021 Mar 07].
Available from: https://doi.org/10.25772/PZM6-S872 ; https://scholarscompass.vcu.edu/etd/6079.
Council of Science Editors:
Ojaghlou N. Adhesion at Solid/Liquid Interfaces. [Doctoral Dissertation]. Virginia Commonwealth University; 2019. Available from: https://doi.org/10.25772/PZM6-S872 ; https://scholarscompass.vcu.edu/etd/6079

Michigan Technological University
10.
Qian, Ziwei.
Effects of Ionic Liquid on Lithium Dendrite Growth.
Degree: MS, Department of Physics, 2018, Michigan Technological University
URL: https://digitalcommons.mtu.edu/etdr/745
► Lithium Dendrites, the microscopic fibers of lithium, often lead to a short circuit in lithium rechargeable batteries that may cause explosions and fires. However,…
(more)
▼ Lithium Dendrites, the microscopic fibers of lithium, often lead to a short circuit in lithium rechargeable batteries that may cause explosions and fires. However, the mechanism for dendrite growth in electrolytes remains unclear. To overcome this problem, we have developed a new Monte Carlo simulation method that simultaneously accounts for dendrite growth and the electrostatic potential in liquids with a minimal set of parameters. Our theory provides a fractal dimension that can be measured experimentally. We examine the fractal structure and the average height of dendrites growing in ionic liquids, with different ion concentration and voltage between electrodes. Our results show that ions can affect the fractal structure and the growth rate of dendrites, and dendrites grow more uniformly and slowly at high ionic strengths and under high voltage.
Advisors/Committee Members: Issei Nakamura.
Subjects/Keywords: Lithium dendrite; ionic liquid; battery; electrodeposition; Monte Carlo; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
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APA (6th Edition):
Qian, Z. (2018). Effects of Ionic Liquid on Lithium Dendrite Growth. (Masters Thesis). Michigan Technological University. Retrieved from https://digitalcommons.mtu.edu/etdr/745
Chicago Manual of Style (16th Edition):
Qian, Ziwei. “Effects of Ionic Liquid on Lithium Dendrite Growth.” 2018. Masters Thesis, Michigan Technological University. Accessed March 07, 2021.
https://digitalcommons.mtu.edu/etdr/745.
MLA Handbook (7th Edition):
Qian, Ziwei. “Effects of Ionic Liquid on Lithium Dendrite Growth.” 2018. Web. 07 Mar 2021.
Vancouver:
Qian Z. Effects of Ionic Liquid on Lithium Dendrite Growth. [Internet] [Masters thesis]. Michigan Technological University; 2018. [cited 2021 Mar 07].
Available from: https://digitalcommons.mtu.edu/etdr/745.
Council of Science Editors:
Qian Z. Effects of Ionic Liquid on Lithium Dendrite Growth. [Masters Thesis]. Michigan Technological University; 2018. Available from: https://digitalcommons.mtu.edu/etdr/745

University of Western Ontario
11.
Wijesekara, Himasha.
Effects of Impurities on Calcium Oxalate Crystallization as Measured by Atomic Force Microscopy.
Degree: 2019, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/6785
► Calcium oxalate crystals are found in kidney stones as either calcium oxalate monohydrate (COM) or calcium oxalate dihydrate (COD). COM crystals are the most abundant…
(more)
▼ Calcium oxalate crystals are found in kidney stones as either calcium oxalate monohydrate (COM) or calcium oxalate dihydrate (COD). COM crystals are the most abundant form as they are thermodynamically more stable than COD crystals under physiological conditions. Certain aspartic acid-rich molecules such as osteopontin (OPN) are known to affect stone formation by inhibiting COM and COD growth. We have studied COM {010} and COD {100} faces in the presence of OPN, poly-aspartic acid (poly-ASP) and synthetic peptides derived from OPN to investigate the inhibitor mechanism.
We observed that poly-ASP preferentially inhibits one particular direction of {010} faces on COM crystals, creating “finger-like” features, while growth continues in other directions. We find that these features appear at a threshold concentration of poly-ASP that varies with the length of the polymer. Attempts to model the threshold concentration suggest that this is due to a competition between adsorption of polymer to already-pinned steps and removal of poly-ASP by desorption and possibly coverage by advancing steps between strongly pinned steps.
Growth of {100} faces of COD crystals in the presence of synthetic peptides derived from OPN with different iso-electric points displayed varying levels of inhibition. The two principal directions of the elongated elliptical hillocks on {100} faces were inhibited to different degrees by the peptides. This preferential inhibition is most likely the result of different Ca2+ ion densities and structures of the two different step directions.
The effects of imaging on the growth itself were studied for the case of COM growth in the presence of OPN. In the presence of OPN molecules, a continuously-scanned area showed faster growth relative to a larger area scanned less frequently. This enhanced vertical growth in the continuously-scanned area was found to vary with the OPN concentration and calcium oxalate supersaturation. We modeled this effect using a modified version of the Cabrera-Vermilyea model (1958), in which steps are pinned by adsorbed impurities, resulting in a decreased propagation speed due to the resulting curvature. In our case, we assume adsorption directly to steps, rather than to terraces as in the Cabrera-Vermilyea model.
Subjects/Keywords: Calcium oxalate monohydrate; Atomic force microscope; Osteopontin; crystal growth; inhibition; kidney stones; Condensed Matter Physics; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Wijesekara, H. (2019). Effects of Impurities on Calcium Oxalate Crystallization as Measured by Atomic Force Microscopy. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/6785
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Wijesekara, Himasha. “Effects of Impurities on Calcium Oxalate Crystallization as Measured by Atomic Force Microscopy.” 2019. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/6785.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Wijesekara, Himasha. “Effects of Impurities on Calcium Oxalate Crystallization as Measured by Atomic Force Microscopy.” 2019. Web. 07 Mar 2021.
Vancouver:
Wijesekara H. Effects of Impurities on Calcium Oxalate Crystallization as Measured by Atomic Force Microscopy. [Internet] [Thesis]. University of Western Ontario; 2019. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/6785.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Wijesekara H. Effects of Impurities on Calcium Oxalate Crystallization as Measured by Atomic Force Microscopy. [Thesis]. University of Western Ontario; 2019. Available from: https://ir.lib.uwo.ca/etd/6785
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Colorado
12.
Edelmaier, Christopher.
Computational Modeling of Mitosis in Fission Yeast.
Degree: PhD, 2018, University of Colorado
URL: https://scholar.colorado.edu/phys_gradetds/237
► Mitosis ensures the proper segregation of chromosomes into daughter cells, which is accomplished by the mitotic spindle. During fission yeast mitosis, chromosomes establish bi-orientation as…
(more)
▼ Mitosis ensures the proper segregation of chromosomes into daughter cells, which is accomplished by the mitotic spindle. During fission yeast mitosis, chromosomes establish bi-orientation as the bipolar spindle assembles, meaning that sister kinetochores become attached to microtubules whose growth was initiated by the two sister poles. This process includes mechanisms that correct erroneous attachments made by the kinetochores during the attachment process. This thesis presents a 3D physical model of spindle assembly in a Brownian dynamics-kinetic Monte Carlo simulation framework and a realistic description of the
physics of microtubule, kinetochore, and chromosome dynamics, in order to interrogate the dynamics and mechanisms of chromosome bi-orientation and error correction. We have added chromosomes to our previous physical model of spindle assembly, which included microtubules, a spherical nuclear envelope, motor proteins, crosslinking proteins, and spindle pole bodies (centrosomes). In this work, we have explored the mechanical properties of kinetochores and their interactions with microtubules that achieve amphitelic spindle attachments at high frequency. A minimal physical model yields simulations that generate chromosome attachment errors, but resolves them, much as normal chromosomes do.
Advisors/Committee Members: Meredith D. Betterton, Matthew A. Glaser, Loren Hough, Thomas Perkins, Richard McIntosh.
Subjects/Keywords: computational; fission; mitosis; nonequilibrium; yeast; Biophysics; Cellular and Molecular Physiology; Statistical, Nonlinear, and Soft Matter Physics
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APA (6th Edition):
Edelmaier, C. (2018). Computational Modeling of Mitosis in Fission Yeast. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/phys_gradetds/237
Chicago Manual of Style (16th Edition):
Edelmaier, Christopher. “Computational Modeling of Mitosis in Fission Yeast.” 2018. Doctoral Dissertation, University of Colorado. Accessed March 07, 2021.
https://scholar.colorado.edu/phys_gradetds/237.
MLA Handbook (7th Edition):
Edelmaier, Christopher. “Computational Modeling of Mitosis in Fission Yeast.” 2018. Web. 07 Mar 2021.
Vancouver:
Edelmaier C. Computational Modeling of Mitosis in Fission Yeast. [Internet] [Doctoral dissertation]. University of Colorado; 2018. [cited 2021 Mar 07].
Available from: https://scholar.colorado.edu/phys_gradetds/237.
Council of Science Editors:
Edelmaier C. Computational Modeling of Mitosis in Fission Yeast. [Doctoral Dissertation]. University of Colorado; 2018. Available from: https://scholar.colorado.edu/phys_gradetds/237

University of Western Ontario
13.
Afrasiabian, Navid.
The journey of a single polymer chain to a nanopore.
Degree: 2020, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/6966
► Single chain translocation has been eagerly studied for more than two decades due to its importance in biological processes and also, providing a better understanding…
(more)
▼ Single chain translocation has been eagerly studied for more than two decades due to its importance in biological processes and also, providing a better understanding of polymer dynamics. Polymer translocation can be divided into three stages of reaching the pore, entering the pore and passing through it. We study the delivery of the chain from the bulk to the entrance, which is called the capture process, for a single chain driven by hydrodynamic flow. Our molecular dynamics-lattice Boltzmann simulations show that the converging flow around the nanopore not only facilitates the process of finding the pore but also deforms the chain in a way that the insertion happens mostly by one of the ends. We explain why single-file capture happens most often despite the formation of folded shapes or hairpins.
Subjects/Keywords: polymer translocation; polymer capture; capture radius; pulley effect; molecular dynamics; lattice-Boltzmann; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Afrasiabian, N. (2020). The journey of a single polymer chain to a nanopore. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/6966
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Afrasiabian, Navid. “The journey of a single polymer chain to a nanopore.” 2020. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/6966.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Afrasiabian, Navid. “The journey of a single polymer chain to a nanopore.” 2020. Web. 07 Mar 2021.
Vancouver:
Afrasiabian N. The journey of a single polymer chain to a nanopore. [Internet] [Thesis]. University of Western Ontario; 2020. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/6966.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Afrasiabian N. The journey of a single polymer chain to a nanopore. [Thesis]. University of Western Ontario; 2020. Available from: https://ir.lib.uwo.ca/etd/6966
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Tennessee – Knoxville
14.
Saadat, Amir.
Large Scale Brownian Dynamics Simulation of Dilute and Semidilute Polymeric Solutions.
Degree: 2016, University of Tennessee – Knoxville
URL: https://trace.tennessee.edu/utk_graddiss/4158
► Excluded Volume (EV) and Hydrodynamic Interactions (HI) play a central role in static and dynamic properties of macromolecules in solution under equilibrium and nonequilibrium settings.…
(more)
▼ Excluded Volume (EV) and Hydrodynamic Interactions (HI) play a central role in static and dynamic properties of macromolecules in solution under equilibrium and nonequilibrium settings. The computational cost of incorporating HI in mesoscale Brownian dynamics (BD) simulations, particularly in the semidilute regime has motivated significant research aimed at development of high-fidelity and efficient techniques.
In this study, I have developed several algorithms for the mesoscale bead-spring representation of a macromolecular solution in dilute and semidilute regimes. The Krylov subspace method enables fast calculation of single chain dynamics with simulation time scaling of O(Nb2) [order N subscript b squared], where Nb is the number of beads in the chain. For simulations of multichain systems, a matrix-free approach is implemented which leads to O(NlogN) scaling of simulation time, where N is the number of beads in the periodic box.
The Krylov and predictor-corrector schemes are used to study the behavior of dilute solutions of high molecular weight flexible macromolecules, and in particular Polystyrene (PS). The influence of HI and EV on the extensional hardening of the macromolecular solutions is considered. It is demonstrated that the combination of HI and successive fine-graining results in a remarkable prediction of rheological properties of solutions containing 1.95, 3.9, and 10.2 million molecular weight PS.
Further, a bead-spring model is developed to overcome the deficiencies of the current mesoscale worm-like chain models, i.e., to accurately describe the correlation along the backbone, segmental length, and the force-extension behavior even at the limit of 1 Kuhn step per spring. The new model is utilized to examine the relaxation and stretching behavior of linear and comb DNA molecules. The BD computational results are in good agreement with single molecule visualization experiments in a cross-slot device (planar extensional flow).
For interacting multichain systems, the fidelity of the matrix-free algorithm is demonstrated by evaluating the asymptotic value of center of mass diffusivity at low concentrations and the radius of gyration as a function of number of beads in θ [theta] and good solvent conditions. Our results are consistent with blob theory, which is commonly used to describe the concentration dependence of polymer solution properties.
Subjects/Keywords: Stochastic Simulations; Mesoscopic Modeling; Extensional Rheology; DNA Dynamics; BDpack; Chemical Engineering; Computational Engineering; Fluid Dynamics; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Saadat, A. (2016). Large Scale Brownian Dynamics Simulation of Dilute and Semidilute Polymeric Solutions. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/4158
Chicago Manual of Style (16th Edition):
Saadat, Amir. “Large Scale Brownian Dynamics Simulation of Dilute and Semidilute Polymeric Solutions.” 2016. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed March 07, 2021.
https://trace.tennessee.edu/utk_graddiss/4158.
MLA Handbook (7th Edition):
Saadat, Amir. “Large Scale Brownian Dynamics Simulation of Dilute and Semidilute Polymeric Solutions.” 2016. Web. 07 Mar 2021.
Vancouver:
Saadat A. Large Scale Brownian Dynamics Simulation of Dilute and Semidilute Polymeric Solutions. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2016. [cited 2021 Mar 07].
Available from: https://trace.tennessee.edu/utk_graddiss/4158.
Council of Science Editors:
Saadat A. Large Scale Brownian Dynamics Simulation of Dilute and Semidilute Polymeric Solutions. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2016. Available from: https://trace.tennessee.edu/utk_graddiss/4158

University of Tennessee – Knoxville
15.
Griffin, Philip James.
Structural Dynamics and Charge Transport in Room Temperature Ionic Liquids.
Degree: 2014, University of Tennessee – Knoxville
URL: https://trace.tennessee.edu/utk_graddiss/2824
► Room temperature ionic liquids are an important class of materials due to their chemical tunability and numerous advantageous physicochemical properties. As a result, ionic liquids…
(more)
▼ Room temperature ionic liquids are an important class of materials due to their chemical tunability and numerous advantageous physicochemical properties. As a result, ionic liquids are currently being investigated for use in a wide array of chemical and electrochemical applications. Despite their great potential, however, the relationship between the chemical structure and physicochemical properties of ionic liquids is not well understood.
To this end, this dissertation presents experimental studies of the reorientational structural dynamics and charge transport properties of a variety of room temperature ionic liquids using quasielastic light scattering spectroscopy and broadband dielectric spectroscopy.
Studies of a series of 1-butyl-3-methylimidazolium based ionic liquids, in which the anion was systematically varied, have revealed that the anion chemical structure has a significant impact on the structural dynamics and charge transport properties of ionic liquids. As the anion becomes larger and more asymmetrical, ionic mobility increases strongly as a result of an increased fluidity. Surprisingly, the mole fraction of free ions remains unaffected by the anion chemical structure.
The influence of cation chemical structure on the transport properties of ionic liquids was explored in a homologous series of tetra-alkylammonium based ionic liquids. It was found that pronounced chemical heterogeneity causes ionic liquids to exhibit complex and strongly heterogeneous molecular dynamics. Furthermore, when aliphatic side-groups of cations occupy a large liquid volume fraction, both the ion mobility as well as the mole fraction of free ions were found to decrease strongly as a consequence of pronounced nanophase segregation.
The transport properties of a novel carboxylic acid-tertiary amine based protic ionic liquid were also studied in this dissertation. The structural dynamics and charge transport mechanism in this protic ionic liquid are surprisingly very similar to the aprotic ionic liquids, despite the fundamental differences in the intrinsic charge carrier.
Through these comparative studies, this dissertation not only provides a fundamental understanding of the unique dynamical properties of room temperature ionic liquids, but it also elucidates the complex interrelationship between key chemical structure variations and molecular transport properties of these important materials.
Subjects/Keywords: ionic liquids; glass transition; dynamics; charge transport; Materials Chemistry; Polymer and Organic Materials; Statistical, Nonlinear, and Soft Matter Physics
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MLA ·
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Export
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APA (6th Edition):
Griffin, P. J. (2014). Structural Dynamics and Charge Transport in Room Temperature Ionic Liquids. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/2824
Chicago Manual of Style (16th Edition):
Griffin, Philip James. “Structural Dynamics and Charge Transport in Room Temperature Ionic Liquids.” 2014. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed March 07, 2021.
https://trace.tennessee.edu/utk_graddiss/2824.
MLA Handbook (7th Edition):
Griffin, Philip James. “Structural Dynamics and Charge Transport in Room Temperature Ionic Liquids.” 2014. Web. 07 Mar 2021.
Vancouver:
Griffin PJ. Structural Dynamics and Charge Transport in Room Temperature Ionic Liquids. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2014. [cited 2021 Mar 07].
Available from: https://trace.tennessee.edu/utk_graddiss/2824.
Council of Science Editors:
Griffin PJ. Structural Dynamics and Charge Transport in Room Temperature Ionic Liquids. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2014. Available from: https://trace.tennessee.edu/utk_graddiss/2824

University of New Mexico
16.
Klickstein, Isaac S.
Target Control of Networked Systems.
Degree: Mechanical Engineering, 2020, University of New Mexico
URL: https://digitalrepository.unm.edu/me_etds/181
► The control of complex networks is an emerging field yet it has already garnered interest from across the scientific disciplines, from robotics to sociology.…
(more)
▼ The control of complex networks is an emerging field yet it has already garnered interest from across the scientific disciplines, from robotics to sociology. It has quickly been noticed that many of the classical techniques from controls engineering, while applicable, are not as illuminating as they were for single systems of relatively small dimension. Instead, properties borrowed from graph theory provide equivalent but more practical conditions to guarantee controllability, reachability, observability, and other typical properties of interest to the controls engineer when dealing with large networked systems. This manuscript covers three topics investigated in detail by the author: (i) the role of the choice of target nodes (system outputs) on the control effort, (ii) creating and analyzing graphs with symmetry, and (iii) the relationship between graph structural properties and control effort.
Advisors/Committee Members: Francesco Sorrentino, Meeko Oishi, Marios Pattichis, John Russell.
Subjects/Keywords: Networks; Optimization; Control; Optimal Control; Control Theory; Discrete Mathematics and Combinatorics; Dynamic Systems; Mechanical Engineering; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
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MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Klickstein, I. S. (2020). Target Control of Networked Systems. (Doctoral Dissertation). University of New Mexico. Retrieved from https://digitalrepository.unm.edu/me_etds/181
Chicago Manual of Style (16th Edition):
Klickstein, Isaac S. “Target Control of Networked Systems.” 2020. Doctoral Dissertation, University of New Mexico. Accessed March 07, 2021.
https://digitalrepository.unm.edu/me_etds/181.
MLA Handbook (7th Edition):
Klickstein, Isaac S. “Target Control of Networked Systems.” 2020. Web. 07 Mar 2021.
Vancouver:
Klickstein IS. Target Control of Networked Systems. [Internet] [Doctoral dissertation]. University of New Mexico; 2020. [cited 2021 Mar 07].
Available from: https://digitalrepository.unm.edu/me_etds/181.
Council of Science Editors:
Klickstein IS. Target Control of Networked Systems. [Doctoral Dissertation]. University of New Mexico; 2020. Available from: https://digitalrepository.unm.edu/me_etds/181

University of Arkansas
17.
Rogers, T. Ryan.
Predicting the Hydration Free Energy of Small Alkanes and Alcohols from Custom, Electronic Structure-Based Force Fields.
Degree: PhD, 2020, University of Arkansas
URL: https://scholarworks.uark.edu/etd/3859
► Mathematical theories reveal the fundamental physics involved in experimentalphenomena. Computer models of such theories are routinely used to corroborate or explain experiments and predict…
(more)
▼ Mathematical theories reveal the fundamental
physics involved in experimentalphenomena. Computer models of such theories are routinely used to corroborate or explain experiments and predict properties of chemical systems. Therefore, an important effort in computational chemistry is the development of more accurate and efficient chemical models. Current-generation models are only beginning to approach experimental-quality predictions of hydration free energies (HFEs).Using computations of quantum mechanical (QM) forces and classical simulations based on these forces, I investigate models to predict several properties of solutes and solutions. This dissertation is a collection of projects exemplifying methods used to gain insight into chemical systems.
Simulations of bulk, supercooled, liquid water using a model based solely on QM data predict an exponential rise in the surface tension with increased supercooling, supporting the existence of a highly debated second phase of liquid water.
A new method for computing static charges of atomic nuclei is derived, which offers a simple and physically sound method that can be used to investigate charge transfer in model systems and generate atomic charges for use in simulations.
Formulae used to calculate HFEs and the assumptions under which they may be equated are investigated, demonstrating that, under physical conditions that validate ideal gas assumptions, theoretical and experimental HFE measurements should be directly comparable. This project also shows how to resolve disagreement between experimental and computational measurements made outside ideal conditions.
Methods for developing custom, QM-based force fields (FFs) by Adaptive Force Matching are described, including specific details for FFs of aqueous methane, ethane, methanol, and ethanol. These FFs are used to predict HFEs and other properties in good agreement with experiments.
These projects demonstrate the capability of computational methods to enhance scientific knowledge when carefully developed from sound theory. Using simple models constructed to reproduce the underlying QM characteristics of a system, classical simulations are able to accurately predict HFEs. Supplemental attachments to the dissertation include the first users’ manual for the CRYOFF software and a tutorial for using CRYOFF in Adaptive Force Matching.
Advisors/Committee Members: Feng Wang, Jingyi Chen, Pradeep Kumar.
Subjects/Keywords: computational chemistry; force fields; free energy; molecular modeling; simulations; solvation; thermodynamics; Other Chemistry; Physical Chemistry; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Rogers, T. R. (2020). Predicting the Hydration Free Energy of Small Alkanes and Alcohols from Custom, Electronic Structure-Based Force Fields. (Doctoral Dissertation). University of Arkansas. Retrieved from https://scholarworks.uark.edu/etd/3859
Chicago Manual of Style (16th Edition):
Rogers, T Ryan. “Predicting the Hydration Free Energy of Small Alkanes and Alcohols from Custom, Electronic Structure-Based Force Fields.” 2020. Doctoral Dissertation, University of Arkansas. Accessed March 07, 2021.
https://scholarworks.uark.edu/etd/3859.
MLA Handbook (7th Edition):
Rogers, T Ryan. “Predicting the Hydration Free Energy of Small Alkanes and Alcohols from Custom, Electronic Structure-Based Force Fields.” 2020. Web. 07 Mar 2021.
Vancouver:
Rogers TR. Predicting the Hydration Free Energy of Small Alkanes and Alcohols from Custom, Electronic Structure-Based Force Fields. [Internet] [Doctoral dissertation]. University of Arkansas; 2020. [cited 2021 Mar 07].
Available from: https://scholarworks.uark.edu/etd/3859.
Council of Science Editors:
Rogers TR. Predicting the Hydration Free Energy of Small Alkanes and Alcohols from Custom, Electronic Structure-Based Force Fields. [Doctoral Dissertation]. University of Arkansas; 2020. Available from: https://scholarworks.uark.edu/etd/3859

University of Western Ontario
18.
Mahagammulla Gamage, Shayamila N.
Development of a 1-Dimensional Data Assimilation to Determine Temperature and Relative Humidity Combining Raman Lidar Backscatter Measurements And a Reanalysis Model.
Degree: 2019, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/6356
► Water vapor is the most dominant greenhouse gas in Earth's atmosphere. It is highly variable and its variations strongly depend on changes in temperature. Atmospheric…
(more)
▼ Water vapor is the most dominant greenhouse gas in Earth's atmosphere. It is highly variable and its variations strongly depend on changes in temperature. Atmospheric water vapor can be expressed as relative humidity (RH), the ratio of the partial pressure of water vapor in the mixture to the equilibrium vapor pressure of water over a flat surface of pure water at a given temperature. Liquid water can exist as super-cooled water for temperatures between 0C to -38C. Thus, RH can be measured either relative to water (RHw) or to ice (RHi). RHi measurements are important in the upper tropospheric region, where the temperature is always less than 0C, to study ice supersaturation (ISS) and its relation to the formation of cirrus clouds.
I present three studies all using a mathematical scheme called the optimal estimation method (OEM). The OEM is an inverse method that determines the most probable state consistent with the measurements and a priori knowledge. These studies use parts of a large set of existing measurements from the Raman Lidar for Meteorological Observations (RALMO) instrument located at the meteorological observatory in Payerne, Switzerland.
I first develop an OEM retrieval for temperature using RALMO's two pure rotational Raman (PRR) channel measurements. Retrieved temperatures show excellent agreement with coincident balloon-borne radiosonde measurements. A second OEM scheme is introduced to retrieve RHw directly from RALMO measurements of back-scatter due to water vapor and nitrogen. I validate the OEM retrievals developed for temperature and RHw. I then combine the OEM-retrieved temperature and RHw with data from the European Centre for Medium-Range Weather Forecasts Re-analysis (ERA5) to compute a new and improved temperature and relative humidity product. The retrieval is enhanced by assimilating it with the ERA5 data. The quality of the RHw retrievals from the assimilated OEM scheme greatly improves over retrievals which use less accurate a priori information.
Thirdly, I retrieve RHi to detect ISS layers. I find the frequency of ISS layers in the free troposphere over Payerne to be about 27% using 82.5 hours of measurements.
Subjects/Keywords: Optimal Estimation Method; Raman lidar; Rotational Raman temperature; UTLS; Water vapor mixing ratio; Relative humidity; Ice supersaturation; Atmospheric Sciences; Meteorology; Physics; Statistical Methodology; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
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APA (6th Edition):
Mahagammulla Gamage, S. N. (2019). Development of a 1-Dimensional Data Assimilation to Determine Temperature and Relative Humidity Combining Raman Lidar Backscatter Measurements And a Reanalysis Model. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/6356
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Mahagammulla Gamage, Shayamila N. “Development of a 1-Dimensional Data Assimilation to Determine Temperature and Relative Humidity Combining Raman Lidar Backscatter Measurements And a Reanalysis Model.” 2019. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/6356.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Mahagammulla Gamage, Shayamila N. “Development of a 1-Dimensional Data Assimilation to Determine Temperature and Relative Humidity Combining Raman Lidar Backscatter Measurements And a Reanalysis Model.” 2019. Web. 07 Mar 2021.
Vancouver:
Mahagammulla Gamage SN. Development of a 1-Dimensional Data Assimilation to Determine Temperature and Relative Humidity Combining Raman Lidar Backscatter Measurements And a Reanalysis Model. [Internet] [Thesis]. University of Western Ontario; 2019. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/6356.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Mahagammulla Gamage SN. Development of a 1-Dimensional Data Assimilation to Determine Temperature and Relative Humidity Combining Raman Lidar Backscatter Measurements And a Reanalysis Model. [Thesis]. University of Western Ontario; 2019. Available from: https://ir.lib.uwo.ca/etd/6356
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Western Ontario
19.
Antipova, Alena.
Dynamics of Discs in a Nematic Liquid Crystal.
Degree: 2016, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/3785
► In this thesis, a new way of simulating a two-way coupling between a liquid crystal and an immersed object is proposed. It can be used…
(more)
▼ In this thesis, a new way of simulating a two-way coupling between a liquid crystal and an immersed object is proposed. It can be used for objects of various geometries and can be expanded to be used for an object of any geometry. Additionally, a simple yet effective model was suggested for calculations of transmitted light through a nematic liquid crystal sample. This model allowed us to clarify the behavior of a ferromagnetic disc in a nematic liquid crystal observed in experiments and incorrectly interpreted at that time.
Our simulations have demonstrated the following: in the absence of external forces and torques, discs with homeotropic (perpendicular) anchoring align with their surface normal parallel to the director of the nematic liquid crystal. In the presence of a weak magnetic field, a ferromagnetic disc will rotate to equilibrate the elastic torque due to the distortion of the nematic director and the magnetic torque. When the magnetic field rotates the disc so that the angle between normal to the surface of the disc and director of the liquid crystal becomes greater than 90 degrees, the disc flips around the axis perpendicular to the rotation axis, thus resolving the distortion in the liquid crystal. An analysis of this behavior was performed in Chapter 3. In particular, we look at the impact of the disc thickness, and conditions on the edges of the object, on defect creation and the flipping transition. We also analyze the importance of backflow (i.e. coupling of tensor order parameter with velocity field). We also study the same system under the action of fast rotating weak magnetic fields, that demonstrates a different behavior: the disc avoids flipping via creation of two symmetric defects on the sides.
Some results on disc pairs are presented in Chapter 4. Interactions between discs, their motion and final position strongly depend on the distance between them, and the magnitude and angular velocity of the rotating magnetic field. Depending on the initial configuration of the system, different stable structures of discs result.
Subjects/Keywords: Liquid Crystals; Lattice Boltzmann; Colloids; Hydrodynamics; Molecular Dynamics; Condensed Matter Physics; Fluid Dynamics; Other Applied Mathematics; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Antipova, A. (2016). Dynamics of Discs in a Nematic Liquid Crystal. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/3785
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Antipova, Alena. “Dynamics of Discs in a Nematic Liquid Crystal.” 2016. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/3785.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Antipova, Alena. “Dynamics of Discs in a Nematic Liquid Crystal.” 2016. Web. 07 Mar 2021.
Vancouver:
Antipova A. Dynamics of Discs in a Nematic Liquid Crystal. [Internet] [Thesis]. University of Western Ontario; 2016. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/3785.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Antipova A. Dynamics of Discs in a Nematic Liquid Crystal. [Thesis]. University of Western Ontario; 2016. Available from: https://ir.lib.uwo.ca/etd/3785
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Kentucky
20.
Farmer, Barry.
EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS.
Degree: 2020, University of Kentucky
URL: https://uknowledge.uky.edu/physastron_etds/76
► Quasicrystals have been shown to exhibit physical properties that are dramatically different from their periodic counterparts. A limited number of magnetic quasicrystals have been fabricated…
(more)
▼ Quasicrystals have been shown to exhibit physical properties that are dramatically different from their periodic counterparts. A limited number of magnetic quasicrystals have been fabricated and measured, and they do not exhibit long-range magnetic order, which is in direct conflict with simulations that indicate such a state should be accessible. This dissertation adopts a metamaterials approach in which artificial quasicrystals are fabricated and studied with the specific goal of identifying how aperiodicity affects magnetic long-range order. Electron beam lithography techniques were used to pattern magnetic thin films into two types of aperiodic tilings, the Penrose P2, and Ammann-Beenker tilings. SQUID magnetometer measurements were performed on sample artificial quasicrystals, and their low-temperature, ground-state magnetization textures were directly imaged using X-ray photoemmission electron microscopy (PEEM) and scanning electron microscopy with polarization analysis (SEMPA) techniques. Monte Carlo simulations of the ground state configurations for Penrose P2 and Ammann-Beenker tilings indicate the emergence of complex ordered sublattices that have not been previously observed in periodic systems. Magnetic imaging of artificial quasicrystals show regions of long-range order in an imperfectly equilibrated state. Defects are found between superdomain walls and between smaller, highly correlated vertex clusters. These results bear on the current lack of evidence for long-range magnetic order in three-dimensional atomic quasicrystals.
Subjects/Keywords: Quasicrystals; Ferromagnetic Domains; Frustrated Magnetism; Artificial Spin Ice; Micromagnetism; Magnetic Order; Condensed Matter Physics; Geometry and Topology; Numerical Analysis and Computation; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Farmer, B. (2020). EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS. (Doctoral Dissertation). University of Kentucky. Retrieved from https://uknowledge.uky.edu/physastron_etds/76
Chicago Manual of Style (16th Edition):
Farmer, Barry. “EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS.” 2020. Doctoral Dissertation, University of Kentucky. Accessed March 07, 2021.
https://uknowledge.uky.edu/physastron_etds/76.
MLA Handbook (7th Edition):
Farmer, Barry. “EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS.” 2020. Web. 07 Mar 2021.
Vancouver:
Farmer B. EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS. [Internet] [Doctoral dissertation]. University of Kentucky; 2020. [cited 2021 Mar 07].
Available from: https://uknowledge.uky.edu/physastron_etds/76.
Council of Science Editors:
Farmer B. EFFECTS OF APERIODICITY AND FRUSTRATION ON THE MAGNETIC PROPERTIES OF ARTIFICIAL QUASICRYSTALS. [Doctoral Dissertation]. University of Kentucky; 2020. Available from: https://uknowledge.uky.edu/physastron_etds/76

West Virginia University
21.
Riggs, Gregory Allen.
Interpretations of Bicoherence in Space & Lab Plasma Dynamics.
Degree: MS, Physics and Astronomy, 2020, West Virginia University
URL: https://doi.org/10.33915/etd.7655
;
https://researchrepository.wvu.edu/etd/7655
► The application of bicoherence analysis to plasma research, particularly in non-linear, coupled-wave regimes, has thus far been significantly belied by poor resolution in time,…
(more)
▼ The application of bicoherence analysis to plasma research, particularly in non-linear, coupled-wave regimes, has thus far been significantly belied by poor resolution in time, and/or outright destruction of frequency information. Though the typical power spectrum cloaks the phase-coherency between frequencies, Fourier transforms of higher-order convolutions provide an
n-dimensional spectrum which is adept at elucidating
n-wave phase coherence. As such, this investigation focuses on the utility of the normalized bispectrum for detection of wave-wave coupling in general, with emphasis on distinct implications within the scope of non-linear plasma
physics. Interpretations of bicoherent features are given for time series from "shots" at the DIII-D tokamak facility; the solar wind, as measured by the
Cluster-II satellite installation; a van der Pol oscillator; and various audio signals, both recorded and contrived. Evaluations of the bicoherence exhibited by simple harmonic relationships are contrasted with those displaying truly non-linear signatures, and the temporal dynamics of their respective bispectra are assessed. Also considered are the curatives and caveats of cogently condensing these 4-dimensional data.
Advisors/Committee Members: Mark Koepke, Paul Cassak.
Subjects/Keywords: Bicoherence; time-series analysis; three-wave coupling; biphase; Applied Statistics; Non-linear Dynamics; Numerical Analysis and Computation; Physics; Plasma and Beam Physics; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Riggs, G. A. (2020). Interpretations of Bicoherence in Space & Lab Plasma Dynamics. (Thesis). West Virginia University. Retrieved from https://doi.org/10.33915/etd.7655 ; https://researchrepository.wvu.edu/etd/7655
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Riggs, Gregory Allen. “Interpretations of Bicoherence in Space & Lab Plasma Dynamics.” 2020. Thesis, West Virginia University. Accessed March 07, 2021.
https://doi.org/10.33915/etd.7655 ; https://researchrepository.wvu.edu/etd/7655.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Riggs, Gregory Allen. “Interpretations of Bicoherence in Space & Lab Plasma Dynamics.” 2020. Web. 07 Mar 2021.
Vancouver:
Riggs GA. Interpretations of Bicoherence in Space & Lab Plasma Dynamics. [Internet] [Thesis]. West Virginia University; 2020. [cited 2021 Mar 07].
Available from: https://doi.org/10.33915/etd.7655 ; https://researchrepository.wvu.edu/etd/7655.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Riggs GA. Interpretations of Bicoherence in Space & Lab Plasma Dynamics. [Thesis]. West Virginia University; 2020. Available from: https://doi.org/10.33915/etd.7655 ; https://researchrepository.wvu.edu/etd/7655
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Portland State University
22.
Shaukat, Kamran.
A study of Leslie model under stochastic environments.
Degree: MS(M.S.) in Physics, Physics, 1981, Portland State University
URL: https://pdxscholar.library.pdx.edu/open_access_etds/3112
► The prediction and analysis of changes in the numbers of biological populations rest on mathematical formulations of demographic events (births and deaths) classified by…
(more)
▼ The prediction and analysis of changes in the numbers of biological populations rest on mathematical formulations of demographic events (births and deaths) classified by the age of individuals. The development of demographic theory when birth and death rates vary statistically over time is the central theme of this work. A study of the standard Leslie model for the demographic dynamics of populations in variable environments is made. At each time interval a Leslie matrix of survival rates and fertilities of a population is chosen according to a Markov process and the population numbers in different age classes are computed. Analytical bounds are developed for the logarithmic growth rate and the age-structure of a population after long times. For a two dimensional case, it is shown analytically that a uniform distribution results for the age-structure if the survival rate from the first to the second age-class is a uniformly distributed random quantity with no serial auto correlation. Numerical studies are made which lead to similar conclusions when the survival rate obeys other distributions. It is found that the variance in the survival parameter is linearly related to the variance in the age structure. An efficient algorithm is developed for numerical simulations on a computer by considering a time sequence of births rather than whole populations. The algorithm is then applied to an example in three dimensions to calculate a sequence of births when the survival rate from the first to the second age-class is a random parameter. Numerical values for the logarithmic growth rate and the logarithmic variance for a population and the probability of extinction are obtained and then compared to the analytical results reported here and elsewhere.
Advisors/Committee Members: S.D. Tuljaapurkar.
Subjects/Keywords: Population – Mathematical models; Physics; Population Biology; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Shaukat, K. (1981). A study of Leslie model under stochastic environments. (Masters Thesis). Portland State University. Retrieved from https://pdxscholar.library.pdx.edu/open_access_etds/3112
Chicago Manual of Style (16th Edition):
Shaukat, Kamran. “A study of Leslie model under stochastic environments.” 1981. Masters Thesis, Portland State University. Accessed March 07, 2021.
https://pdxscholar.library.pdx.edu/open_access_etds/3112.
MLA Handbook (7th Edition):
Shaukat, Kamran. “A study of Leslie model under stochastic environments.” 1981. Web. 07 Mar 2021.
Vancouver:
Shaukat K. A study of Leslie model under stochastic environments. [Internet] [Masters thesis]. Portland State University; 1981. [cited 2021 Mar 07].
Available from: https://pdxscholar.library.pdx.edu/open_access_etds/3112.
Council of Science Editors:
Shaukat K. A study of Leslie model under stochastic environments. [Masters Thesis]. Portland State University; 1981. Available from: https://pdxscholar.library.pdx.edu/open_access_etds/3112

University of Vermont
23.
Pond, Tyson Charles.
Measuring and Modeling Information Flow on Social Networks.
Degree: MS, Mathematics, 2020, University of Vermont
URL: https://scholarworks.uvm.edu/graddis/1239
► With the rise of social media, researchers have become increasingly interested in understanding how individuals inform, influence, and interact with others in their social…
(more)
▼ With the rise of social media, researchers have become increasingly interested in understanding how individuals inform, influence, and interact with others in their social network and how the network mediates the flow of information. Previous research on information flow has primarily used models of contagion to study the adoption of a technology, propagation of purchase recommendations, or virality of online activity. Social (or "complex") contagions spread differently than biological ("simple") contagions. A limitation when researchers validate contagion models is that they neglect much of the massive amounts of data now available through online social networks. Here we model a recently proposed information-theoretic approach to measuring the flow of written information in data. We use an idealized generative model for text data – the quoter model – which naturally incorporates this measure. We investigate how network structure impacts information flow and find that the quoter model exhibits interesting features similar to those of complex contagion. Finally, we offer an analytical treatment of the quoter model: we derive approximate calculations and show dependence on model parameters. This thesis gives rise to new hypotheses about the role of the social network in facilitating information flow, which future research can investigate using real-world data.
Advisors/Committee Members: James P. Bagrow.
Subjects/Keywords: complex systems; entropy; information diffusion; network science; probability; social dynamics; Applied Mathematics; Library and Information Science; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Pond, T. C. (2020). Measuring and Modeling Information Flow on Social Networks. (Thesis). University of Vermont. Retrieved from https://scholarworks.uvm.edu/graddis/1239
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Pond, Tyson Charles. “Measuring and Modeling Information Flow on Social Networks.” 2020. Thesis, University of Vermont. Accessed March 07, 2021.
https://scholarworks.uvm.edu/graddis/1239.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Pond, Tyson Charles. “Measuring and Modeling Information Flow on Social Networks.” 2020. Web. 07 Mar 2021.
Vancouver:
Pond TC. Measuring and Modeling Information Flow on Social Networks. [Internet] [Thesis]. University of Vermont; 2020. [cited 2021 Mar 07].
Available from: https://scholarworks.uvm.edu/graddis/1239.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Pond TC. Measuring and Modeling Information Flow on Social Networks. [Thesis]. University of Vermont; 2020. Available from: https://scholarworks.uvm.edu/graddis/1239
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

New Jersey Institute of Technology
24.
Datta, Subha.
Dimension reduction techniques for high dimensional and ultra-high dimensional data.
Degree: PhD, Mathematical Sciences, 2019, New Jersey Institute of Technology
URL: https://digitalcommons.njit.edu/dissertations/1432
► This dissertation introduces two statistical techniques to tackle high-dimensional data, which is very commonplace nowadays. It consists of two topics which are inter-related by…
(more)
▼ This dissertation introduces two
statistical techniques to tackle high-dimensional data, which is very commonplace nowadays. It consists of two topics which are inter-related by a common link, dimension reduction.
The first topic is a recently introduced classification technique, the weighted principal support vector machine (WPSVM), which is incorporated into a spatial point process framework. The WPSVM possesses an additional parameter, a weight parameter, besides the regularization parameter. Most
statistical techniques, including WPSVM, have an inherent assumption of independence, which means the data points are not connected with each other in any manner. But spatial data violates this assumption. Correlation between two spatial data points increases as the distance between them decreases. However, under some conditions on the spatial point process, the WPSVM is still valid. Furthermore, through extensive simulations it has been shown that WPSVM performs better than other dimension reduction techniques. The main advantage of WPSVM comes from the fact that it can handle non-linear relationships. WPSVM is also applied to a rainforest dataset.
The second topic talks about another recently introduced technique, joint-screening. Unlike the previous method, this works for ultra-high dimensional data (p >> n). Most existing variable screening methods fail to identify those marginally unimportant but jointly important genetic variables. The joint screening (JS) procedure screens all the covariates at the same time based on a criterion. In this way a subset of variables that are suspected to be highly associated with the outcome can be identified. One massive advantage of the JS procedure comes from the fact that it is computationally simple and easy to understand. The performance of the proposed JS procedure is evaluated via simulation studies and an application to the Genetics Analysis Workshop 20 data.
Advisors/Committee Members: Ji Meng Loh, Yixin Fang, Sunil Kumar Dhar.
Subjects/Keywords: Big data; High-dimensional; Spatial statistics; Ultra high-dimensional; Weighted principal support vector machine; Applied Mathematics; Mathematics; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Datta, S. (2019). Dimension reduction techniques for high dimensional and ultra-high dimensional data. (Doctoral Dissertation). New Jersey Institute of Technology. Retrieved from https://digitalcommons.njit.edu/dissertations/1432
Chicago Manual of Style (16th Edition):
Datta, Subha. “Dimension reduction techniques for high dimensional and ultra-high dimensional data.” 2019. Doctoral Dissertation, New Jersey Institute of Technology. Accessed March 07, 2021.
https://digitalcommons.njit.edu/dissertations/1432.
MLA Handbook (7th Edition):
Datta, Subha. “Dimension reduction techniques for high dimensional and ultra-high dimensional data.” 2019. Web. 07 Mar 2021.
Vancouver:
Datta S. Dimension reduction techniques for high dimensional and ultra-high dimensional data. [Internet] [Doctoral dissertation]. New Jersey Institute of Technology; 2019. [cited 2021 Mar 07].
Available from: https://digitalcommons.njit.edu/dissertations/1432.
Council of Science Editors:
Datta S. Dimension reduction techniques for high dimensional and ultra-high dimensional data. [Doctoral Dissertation]. New Jersey Institute of Technology; 2019. Available from: https://digitalcommons.njit.edu/dissertations/1432

University of Western Ontario
25.
Abeyasinghe, Pubuditha M.
Calculating the Dimensionality of the Brain, and Other Applications of an Optimized Generalized Ising Model in Predicting Brain's Spontaneous Functions.
Degree: 2019, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/6124
► Understanding a system as complex as the human brain is a very demanding task. Directly working with structural and functional neuroimaging data has led to…
(more)
▼ Understanding a system as complex as the human brain is a very demanding task. Directly working with structural and functional neuroimaging data has led to most of the understanding we have gained about the human brain. However, performing only the direct statistical comparisons on the empirical function and the structure does not fully explain the observed long-range functional correlations. Therefore, implementations of mathematical models to gain further understanding of the relationship between the structure and function of the brain is critical. Additionally, spontaneous functions of the brain can only be predicted using computer simulated models; which will be pivotal for studying the patients with accidental brain injuries. Therefore, this research aims to present an optimized computer simulated model not only to further understand the structure-function relationship of the brain but also to predict the functional changes when anatomy is altered.
Based on prior work, 2-dimensional classical Ising model stands out among the other models in modeling the functions of the brain due to its simplicity. Hence, a 2-dimensional Ising model was simulated on a structural connectome (generalized Ising model) that acts as a proxy for the anatomical connectivity in the brain. Simulations allowed the prediction of functional connectivity using the structure, at criticality. It also enabled the introduction of a novel methodology to calculate the ”dimensionality” of the brain. Our results showed the dimensionality of a healthy brain is two when it is defined using the information flow in the brain. Further research illustrated the dependency of dimensionality on the diffusion tractography method used to obtain the structural connectome. It was also concluded that an optimized generalized Ising model has to be simulated using a structural connectome generated by deterministic tractography to acquire the best predictions of empirical function. Additional investigations into a more generalized version of the Ising model—Potts model with different number of spin states—illustrated that increasing the number of spin states does not increase the predictability. It also supported the hypothesis that the model could be simulating the digital nature of direct neural activity rather than the indirect activity measured by brain imaging.
Subjects/Keywords: Dimensionality of the brain; 2D classical Ising model; Generalized Ising model; Structure-function relationship of the brain; Tractography; Potts model; Computational Neuroscience; Statistical, Nonlinear, and Soft Matter Physics
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Abeyasinghe, P. M. (2019). Calculating the Dimensionality of the Brain, and Other Applications of an Optimized Generalized Ising Model in Predicting Brain's Spontaneous Functions. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/6124
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Abeyasinghe, Pubuditha M. “Calculating the Dimensionality of the Brain, and Other Applications of an Optimized Generalized Ising Model in Predicting Brain's Spontaneous Functions.” 2019. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/6124.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Abeyasinghe, Pubuditha M. “Calculating the Dimensionality of the Brain, and Other Applications of an Optimized Generalized Ising Model in Predicting Brain's Spontaneous Functions.” 2019. Web. 07 Mar 2021.
Vancouver:
Abeyasinghe PM. Calculating the Dimensionality of the Brain, and Other Applications of an Optimized Generalized Ising Model in Predicting Brain's Spontaneous Functions. [Internet] [Thesis]. University of Western Ontario; 2019. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/6124.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Abeyasinghe PM. Calculating the Dimensionality of the Brain, and Other Applications of an Optimized Generalized Ising Model in Predicting Brain's Spontaneous Functions. [Thesis]. University of Western Ontario; 2019. Available from: https://ir.lib.uwo.ca/etd/6124
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Western Ontario
26.
Kandeepan, Sivayini.
Studying Resting State and Stimulus Induced BOLD Activity using the Generalized Ising Model and Independent Component Graph Analysis.
Degree: 2020, University of Western Ontario
URL: https://ir.lib.uwo.ca/etd/6801
► Although many technical advancements have been made, neuroscientists still struggle to explain the underlying behaviour of how brain regions communicate with each other to form…
(more)
▼ Although many technical advancements have been made, neuroscientists still struggle to explain the underlying behaviour of how brain regions communicate with each other to form large-scale functional networks. functional Magnetic Resonance Imaging (fMRI) has been commonly used to investigate changes between brain regions over time using the Blood Oxygen Level Dependent (BOLD) signal.
The goal of this thesis is to show the applicability of novel techniques and tools, such as the generalized Ising model (GIM) and the independent component graph analysis (GraphICA), to obtain information on the functional connectivity of populations with altered perception of consciousness. The GIM was used to model brain activity in healthy brains during various stages of consciousness, as induced by an anesthetic agent, propofol, in the auditory paradigm. GraphICA, a tool that combines ICA and graph theory was used to investigate the functional connectivity of resting state networks (RSNs) in patients with altered perception caused by tinnitus and in patients with altered states of consciousness caused by severe brain injury. For the tinnitus patients, we examined whether a correlation exists between tinnitus behavioural scores and functional brain connectivity of RSNs. Moreover, for the severely brain injured patients, a multimodal neuroimaging approach with hybrid FDG-PET/MRI was implemented to study the functional connectivity changes of the RSNs.
The GIM simulated with an external field was able to model the brain activity at different levels of consciousness under naturalistic stimulation, at a temperature in the super critical regime. Further, a strong correlation was observed between tinnitus distress and the connectivity pattern within and between the right executive control network and the other RSNs. This suggests that tinnitus distress is the consequence of a hyperactive attention condition. A variability was observed in the appearance and temporal/spatial patterns of RSNs among the two resting state fMRI acquisitions acquired within the same scanning session of the severely brain injured patients. This suggests the need for new strategies to be developed in order to pick the best RSN from each acquisition. Overall, this work demonstrated that the GIM and GraphICA were promising tools to investigate brain activity of populations with altered perception of consciousness and in future can be extended to investigate different neurological populations.
Subjects/Keywords: Resting state fMRI; Generalized Ising model; Graph theory; Independent component analysis; Naturalistic external stimuli; Altered perception of consciousness; Statistical, Nonlinear, and Soft Matter Physics
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APA (6th Edition):
Kandeepan, S. (2020). Studying Resting State and Stimulus Induced BOLD Activity using the Generalized Ising Model and Independent Component Graph Analysis. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/6801
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kandeepan, Sivayini. “Studying Resting State and Stimulus Induced BOLD Activity using the Generalized Ising Model and Independent Component Graph Analysis.” 2020. Thesis, University of Western Ontario. Accessed March 07, 2021.
https://ir.lib.uwo.ca/etd/6801.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kandeepan, Sivayini. “Studying Resting State and Stimulus Induced BOLD Activity using the Generalized Ising Model and Independent Component Graph Analysis.” 2020. Web. 07 Mar 2021.
Vancouver:
Kandeepan S. Studying Resting State and Stimulus Induced BOLD Activity using the Generalized Ising Model and Independent Component Graph Analysis. [Internet] [Thesis]. University of Western Ontario; 2020. [cited 2021 Mar 07].
Available from: https://ir.lib.uwo.ca/etd/6801.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kandeepan S. Studying Resting State and Stimulus Induced BOLD Activity using the Generalized Ising Model and Independent Component Graph Analysis. [Thesis]. University of Western Ontario; 2020. Available from: https://ir.lib.uwo.ca/etd/6801
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
27.
Park, Jungeun.
Enzymatically active microspheres for self-propelled colloidal engines.
Degree: Master of Engineering (M.E.), Chemical Engineering, 2017, City University of New York
URL: https://academicworks.cuny.edu/cc_etds_theses/671
► Micro- and nano-motors have attracted numerous attentions from various scientific areas due to their potential applications. Most studies on self-propelled colloidal engines have exploited…
(more)
▼ Micro- and nano-motors have attracted numerous attentions from various scientific areas due to their potential applications. Most studies on self-propelled colloidal engines have exploited catalytic decomposition of hydrogen peroxide to drive the motor. Since the hydrogen peroxide is caustic, it is not suitable to use in biological applications, encouraging people to develop “greener” fuels. The aim of this research is to study a new transduction mechanism for self-propulsion not tied to hydrogen peroxide, and which can in particular be used with biological molecules as fuels. In this study, we focus on making particles with enzymatic activity which can effectively decompose biomolecules for self-propulsion. We select elastase as a catalyst and coat it on the surface of polystyrene (PS) particles, and use SucAla
3-pNA as a substrate to examine the activity of the elastase-coated particles. We exploit biotin-streptavidin chemistry to couple the elastase on the surface of the PS particles. We confirm that SucAla
3-pNA can be effectively decomposed by elastase and elastase-coated particles using spectrophotometric measurement. The results demonstrate that the elastase-coated PS particles are catalytically active, showing great potential to be used in biologically-friendly system.
Advisors/Committee Members: Charles Maldarelli.
Subjects/Keywords: Self-propelled colloids; Enzyme; Elastase; Active colloids; Microspheres; Biochemical and Biomolecular Engineering; Biochemistry; Other Chemical Engineering; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Park, J. (2017). Enzymatically active microspheres for self-propelled colloidal engines. (Thesis). City University of New York. Retrieved from https://academicworks.cuny.edu/cc_etds_theses/671
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Park, Jungeun. “Enzymatically active microspheres for self-propelled colloidal engines.” 2017. Thesis, City University of New York. Accessed March 07, 2021.
https://academicworks.cuny.edu/cc_etds_theses/671.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Park, Jungeun. “Enzymatically active microspheres for self-propelled colloidal engines.” 2017. Web. 07 Mar 2021.
Vancouver:
Park J. Enzymatically active microspheres for self-propelled colloidal engines. [Internet] [Thesis]. City University of New York; 2017. [cited 2021 Mar 07].
Available from: https://academicworks.cuny.edu/cc_etds_theses/671.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Park J. Enzymatically active microspheres for self-propelled colloidal engines. [Thesis]. City University of New York; 2017. Available from: https://academicworks.cuny.edu/cc_etds_theses/671
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Arkansas
28.
Hillhouse, Brian David.
Fatigue Performance and Shear Demand Distributions of Clustered Shear Connectors in Composite Bridge Girders.
Degree: MSCE, 2018, University of Arkansas
URL: https://scholarworks.uark.edu/etd/3059
► The current American Association of State Highway and Transportation Officials (AASHTO) Bridge Specifications assumes uniform shear flow demands at the steel-concrete interface of composite…
(more)
▼ The current American Association of State Highway and Transportation Officials (AASHTO) Bridge Specifications assumes uniform shear flow demands at the steel-concrete interface of composite bridge girders. As stud pitch increases to beyond 24 in or as studs become clustered to account for pre-cast concrete decks, this assumed shear demand distribution may be unrepresentative. Understanding shear transfer and resulting demands on headed studs in composite beams are important for ensuring adequate composite design. This study investigates stud demands in composite bridge girders using large-scale fatigue testing and direct pressure measurements for stud force calculations. In this study, two large-scale composite beam specimens were fatigue tested to determine the effects of stud clustering on stud shear demands and fatigue life. One additional non-composite beam specimen was also fatigue tested to determine potential composite action performance and degradation following fatigue loading. All composite specimens were designed based on the stud strength limit state resulting in an expected finite fatigue life. Studs within the composite test specimens were instrumented with transverse pressure gauges capable of measuring concrete contact forces. Results from the two composite beam tests indicated that stud shear demands were lower than the AASHTO estimations (fatigue life exceeded code expectations by over 250%). Stud pressure measurements during fatigue testing indicated stud demands that were nearly 66% lower than those estimated by AASHTO. From the pressure measurements it was observed that the exterior rows of clustered shear studs felt a higher shear force than interior studs. Results from the non-composite specimen indicated composite behavior through alternative shear transfer mechanisms as a shift in the steel beam neutral axis toward the concrete slab was observed.
Advisors/Committee Members: Gary Prinz, Micah Hale, Cameron Murray.
Subjects/Keywords: Composite Bridge Girders; Fatigue Testing; Pressure Measurement Gauge; Shear Demands; Shear Studs; Civil Engineering; Construction Engineering and Management; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Hillhouse, B. D. (2018). Fatigue Performance and Shear Demand Distributions of Clustered Shear Connectors in Composite Bridge Girders. (Masters Thesis). University of Arkansas. Retrieved from https://scholarworks.uark.edu/etd/3059
Chicago Manual of Style (16th Edition):
Hillhouse, Brian David. “Fatigue Performance and Shear Demand Distributions of Clustered Shear Connectors in Composite Bridge Girders.” 2018. Masters Thesis, University of Arkansas. Accessed March 07, 2021.
https://scholarworks.uark.edu/etd/3059.
MLA Handbook (7th Edition):
Hillhouse, Brian David. “Fatigue Performance and Shear Demand Distributions of Clustered Shear Connectors in Composite Bridge Girders.” 2018. Web. 07 Mar 2021.
Vancouver:
Hillhouse BD. Fatigue Performance and Shear Demand Distributions of Clustered Shear Connectors in Composite Bridge Girders. [Internet] [Masters thesis]. University of Arkansas; 2018. [cited 2021 Mar 07].
Available from: https://scholarworks.uark.edu/etd/3059.
Council of Science Editors:
Hillhouse BD. Fatigue Performance and Shear Demand Distributions of Clustered Shear Connectors in Composite Bridge Girders. [Masters Thesis]. University of Arkansas; 2018. Available from: https://scholarworks.uark.edu/etd/3059

University of Arkansas
29.
Moore, Tyler Garrett.
Directed Percolation and the Abstract Tile Assembly Model.
Degree: MS, 2013, University of Arkansas
URL: https://scholarworks.uark.edu/etd/765
► Self-assembly is a process by which simple components build complex structures through local interactions. Directed percolation is a statistical physical model for describing competitive…
(more)
▼ Self-assembly is a process by which simple components build complex structures through local interactions. Directed percolation is a
statistical physical model for describing competitive spreading processes on lattices. The author describes an algorithm which can transform a tile assembly system in the abstract Tile Assembly Model into a directed percolation problem, and then shows simulations of the aTAM which support this algorithm. The author also investigates two new constructs designed for Erik Winfree's abstract Tile Assembly Model called the NULL tile and temperature 1.5. These constructs aid the translation between self-assembly and directed percolation and may assist self-assembly researchers in designing tilesets in the aTAM with non-deterministic local properties, but guaranteed global properties. Temperature 1.5 results indicate the brittleness of the standard temperature 2 tile assembly system, and the NULL tile is shown to assist simulations of large assembly processes while also reinforcing the need for variable temperature models to more closely simulate laboratory self-assembly.
Advisors/Committee Members: Russell Deaton, Gordon Beavers, Wing Ning Li.
Subjects/Keywords: Applied sciences; Abstract tile assembly model; Percolation theory; Self assembly; Nanoscience and Nanotechnology; Numerical Analysis and Scientific Computing; Statistical, Nonlinear, and Soft Matter Physics
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APA ·
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MLA ·
Vancouver ·
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Export
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APA (6th Edition):
Moore, T. G. (2013). Directed Percolation and the Abstract Tile Assembly Model. (Masters Thesis). University of Arkansas. Retrieved from https://scholarworks.uark.edu/etd/765
Chicago Manual of Style (16th Edition):
Moore, Tyler Garrett. “Directed Percolation and the Abstract Tile Assembly Model.” 2013. Masters Thesis, University of Arkansas. Accessed March 07, 2021.
https://scholarworks.uark.edu/etd/765.
MLA Handbook (7th Edition):
Moore, Tyler Garrett. “Directed Percolation and the Abstract Tile Assembly Model.” 2013. Web. 07 Mar 2021.
Vancouver:
Moore TG. Directed Percolation and the Abstract Tile Assembly Model. [Internet] [Masters thesis]. University of Arkansas; 2013. [cited 2021 Mar 07].
Available from: https://scholarworks.uark.edu/etd/765.
Council of Science Editors:
Moore TG. Directed Percolation and the Abstract Tile Assembly Model. [Masters Thesis]. University of Arkansas; 2013. Available from: https://scholarworks.uark.edu/etd/765

University of Tennessee – Knoxville
30.
Duranty, Edward Roy.
The Effect of Composition and Architecture on Polymer Behavior in Homopolymer Blends and Inter-filament Bonding in 3D Printed Models.
Degree: 2015, University of Tennessee – Knoxville
URL: https://trace.tennessee.edu/utk_graddiss/3545
► This dissertation presents work that increases our understanding of the effects of composition and architecture on copolymer structure and dynamics and how they affect material…
(more)
▼ This dissertation presents work that increases our understanding of the effects of composition and architecture on copolymer structure and dynamics and how they affect material diffusion between filaments in a 3D printed model. Copolymers are polymer chains made up of at least two different monomers. The ordering and arrangement of the two monomer species within a copolymer can have drastic effects on the behavior and properties of the copolymer.
The first chapter of this dissertation examines how the copolymer composition affects the structure and dynamics of the chain in a homopolymer blend. This study used a modified Monte Carlo BFM to simulate random polystyrene(PS)-polymethymethacrylate(PMMA) copolymers in a PMMA matrix. The results suggest that the faster moving PS segments in the copolymer chain dominate the chain’s motion. However, concentration fluctuations in the local volume around segments of the chain ultimately slow the chain down. This work sheds light into why a randomly distributed copolymer will move faster than a di-block copolymer of the same monomer composition.
The next project focused on the effect of copolymer architecture on the structure and dynamics of branched polymers in a homopolymer matrix using a Monte Carlo simulation. In these simulations, branched polymer consisted of a backbone and the side-chains being unlike monomer species. The number and the molecular weight of the branches was varied to study the effects of branch packing densities on homopolymer copolymer comb structure and motion. Additionally, the temperature varied to determine the effect of available thermal energy on each architectural copolymer configuration. The results of this project concluded that the structure and motion of a branched polymer are a result of the balance in the thermodynamic environment surrounding the copolymer.
Finally, the effect of inter-filament heat and copolymer diffusion on inter-filament bonding in 3D printed part was examined. In this study the importance of thermal history in the print environment was determined quantitatively and its effect on the adhesion between acrylonitrile-butadiene-styrene (ABS) copolymer filaments was probed. Additionally, the interface between ABS filaments was improved using a chemical cross-linker. These studies provide insight into improving the mechanical strength of 3D printed parts.
Subjects/Keywords: copolymer dynamics; copolymer architecture; 3D printing; fused deposition modeling; Monte Carlo simulation; polymer; Materials Chemistry; Polymer Chemistry; Statistical, Nonlinear, and Soft Matter Physics
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Duranty, E. R. (2015). The Effect of Composition and Architecture on Polymer Behavior in Homopolymer Blends and Inter-filament Bonding in 3D Printed Models. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/3545
Chicago Manual of Style (16th Edition):
Duranty, Edward Roy. “The Effect of Composition and Architecture on Polymer Behavior in Homopolymer Blends and Inter-filament Bonding in 3D Printed Models.” 2015. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed March 07, 2021.
https://trace.tennessee.edu/utk_graddiss/3545.
MLA Handbook (7th Edition):
Duranty, Edward Roy. “The Effect of Composition and Architecture on Polymer Behavior in Homopolymer Blends and Inter-filament Bonding in 3D Printed Models.” 2015. Web. 07 Mar 2021.
Vancouver:
Duranty ER. The Effect of Composition and Architecture on Polymer Behavior in Homopolymer Blends and Inter-filament Bonding in 3D Printed Models. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2015. [cited 2021 Mar 07].
Available from: https://trace.tennessee.edu/utk_graddiss/3545.
Council of Science Editors:
Duranty ER. The Effect of Composition and Architecture on Polymer Behavior in Homopolymer Blends and Inter-filament Bonding in 3D Printed Models. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2015. Available from: https://trace.tennessee.edu/utk_graddiss/3545
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