Modeling Out-Of-Plane Actuation In Thin-Film Nematic Polymer Networks: From Chiral Ribbons To Auto-Origami Boxes Via Twist And Topology, 2017 Kent State University

#### Modeling Out-Of-Plane Actuation In Thin-Film Nematic Polymer Networks: From Chiral Ribbons To Auto-Origami Boxes Via Twist And Topology, Vianney Gimenez-Pinto, Fangfu Ye, Badel Mbanga, Jonathan Selinger, Robin Selinger

*Jonathan Selinger*

Effect Of Interstitial Fluid On The Fraction Of Flow Microstates That Precede Clogging In Granular Hoppers, 2017 University of Pennsylvania

#### Effect Of Interstitial Fluid On The Fraction Of Flow Microstates That Precede Clogging In Granular Hoppers, Juha Koivisto, Douglas J. Durian

*Department of Physics Papers*

We report on the nature of flow events for the gravity-driven discharge of glass beads through a hole that is small enough that the hopper is susceptible to clogging. In particular, we measure the average and standard deviation of the distribution of discharged masses as a function of both hole and grain sizes. We do so in air, which is usual, but also with the system entirely submerged under water. This damps the grain dynamics and could be expected to dramatically affect the distribution of the flow events, which are described in prior work as avalanche-like. Though the flow is ...

Universal Slip Dynamics In Metallic Glasses And Granular Matter – Linking Frictional Weakening With Inertial Effects, 2017 Bucknell University

#### Universal Slip Dynamics In Metallic Glasses And Granular Matter – Linking Frictional Weakening With Inertial Effects, Dmitri V. Denisov, Kinga A. Lorincz, Wendelin J. Wright, Todd C. Hufnagel, Aya Nawano, Xiaojun Gu, Jonathan T. Uhl, Karin A. Dahmen, Peter Schall

*Faculty Journal Articles*

Slowly strained solids deform via intermittent slips that exhibit a material-independent critical size distribution. Here, by comparing two disparate systems - granular materials and bulk metallic glasses - we show evidence that not only the statistics of slips but also their dynamics are remarkably similar, i.e. independent of the microscopic details of the material. By resolving and comparing the full time evolution of avalanches in bulk metallic glasses and granular materials, we uncover a regime of universal deformation dynamics. We experimentally verify the predicted universal scaling functions for the dynamics of individual avalanches in both systems, and show that both the ...

Relaxation Of Charge In Monolayer Graphene: Fast Nonlinear Diffusion Versus Coulomb Effects, 2017 University of Virginia

#### Relaxation Of Charge In Monolayer Graphene: Fast Nonlinear Diffusion Versus Coulomb Effects, Eugene B. Kolomeisky, Joseph P. Straley

*Physics and Astronomy Faculty Publications*

Pristine monolayer graphene exhibits very poor screening because the density of states vanishes at the Dirac point. As a result, charge relaxation is controlled by the effects of zero-point motion (rather than by the Coulomb interaction) over a wide range of parameters. Combined with the fact that graphene possesses finite intrinsic conductivity, this leads to a regime of relaxation described by a nonlinear diffusion equation with a diffusion coefficient that diverges at zero charge density. Some consequences of this fast diffusion are self-similar superdiffusive regimes of relaxation, the development of a charge depleted region at the interface between electron- and ...

Code For "Noise-Enhanced Coding In Phasic Neuron Spike Trains", 2017 Virginia Commonwealth University

#### Code For "Noise-Enhanced Coding In Phasic Neuron Spike Trains", Cheng Ly, Brent D. Doiron

*Statistical Sciences and Operations Research Data*

This zip file contains Matlab scripts and ode (XPP) files to calculate the statistics of the models in "Noise-Enhanced Coding in Phasic Neuron Spike Trains". This article is published in PLoS ONE.

Tensor Renormalization Group Method Study In Z5 Model, 2017 University of Iowa

#### Tensor Renormalization Group Method Study In Z5 Model, Zhuohao Liu

*Honors Theses at the University of Iowa*

This thesis describes the Tensor Renormalization Group (TRG) method used to solve the Z5 model in lattice gauge theory. The TRG method provides exact blocking for the models and is much less expansive in terms of computational costs. Here we consider the Z5 model in two dimensions, we discuss the formulation of the tensor and the process we used to do the TRG blocking, in order to find the phase transition and critical behavior of the model. We give some simple results and plots, and some expectation for further research in the model.

Two-Photon Polymerization Of Soft Matter Composites, 2017 University of Colorado, Boulder

#### Two-Photon Polymerization Of Soft Matter Composites, Yasser Albarakat

*Undergraduate Honors Theses*

With two-photon photopolymerization (2PP), it is possible to design and produce composite materials with three dimensional control and sub-micron precision, thanks to highly localized nonlinear process of polymerization. In this work, the feasibility of fabricating mesostructured composite particles with pre-defined shape and topology is examined. We explored polymerizable materials from both commercial sources and laboratory products as well as variable laser parameters, including pulse width and intensity along with dwell time, to find optimum conditions for 2PP. Later 2PP was performed on polymerizable materials containing quantum dots dispersion and the optical response of the resultant composite was characterized with spectroscopy ...

Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, 2017 University of Massachusetts, Amherst

#### Analyses Of Densely Crosslinked Phenolic Systems Using Low Field Nmr, Jigneshkumar Patel

*Doctoral Dissertations*

A uniform dispersion of reactants is necessary to achieve a complete reaction involving multi-components, especially for the crosslinking of rigid high-performance materials. In these reactions, miscibility is crucial for curing efficiency. This miscibility is typically enhanced by adding a third component, a plasticizer. For the reaction of the highly crystalline crosslinking agent hexamethylenetetramine (HMTA) with a strongly hydrogen-bonded phenol formaldehyde resin, furfural has been traditionally used as the plasticizer. However, the reason for its effectiveness is not clear. In this doctoral thesis work, miscibility and crosslinking efficiency of plasticizers in phenolic curing reactions are studied by thermal analysis and spectroscopic ...

Morphology Of Thin Sheets In The Lame Setup And Beyond, 2017 University of Massachusetts - Amherst

#### Morphology Of Thin Sheets In The Lame Setup And Beyond, Zhanlong Qiu

*Doctoral Dissertations*

We present a general analytical approach to study the wrinkling phenomena in the Lame, sheet on drop, drop on sheet, and twisted ribbon setups. In the partially single-mode wrinkle pattern, we employ the boundary layer analysis to regularize the divergence in the energy and obtain the optimal wavenumber. In the multi-mode wrinkle pattern scenario, we consider the effects of the boundary condition, meniscus, and the geometry of the setup separately on the energies and obtain scaling results for the wavenumber of the multi-mode pattern due to each effect. Lastly, a wrinkle-to-fold transition is discussed in the Lame setup, with our ...

Variable Structure Feedback Control With Application To Spacecraft With Small Thrust Propulsion Systems, 2017 Embry-Riddle Aeronautical University

#### Variable Structure Feedback Control With Application To Spacecraft With Small Thrust Propulsion Systems, Samuel J. Kitchen-Mckinley

*Dissertations and Theses*

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 ...

Assembly Of Particles Onto Rigid Cylinders And Flexible Membranes: Probing Effects Of Surface Curvature And Deformation, 2017 University of Massachusetts Amherst

#### Assembly Of Particles Onto Rigid Cylinders And Flexible Membranes: Probing Effects Of Surface Curvature And Deformation, Derek Wood

*Doctoral Dissertations*

In this thesis we explore two specific topics within the broad field of particle adhesion. First, we examine the effect of substrate shape and geometry on the self assembly of adsorbed particles, by performing molecular dynamics simulations of interacting particles constrained to the surface of cylinders of varying diameters. We find the diameter of the cylinder imposes a constraint on the shape and crystallographic orientation of the self-assembled lattice, essentially determining the optimal arrangement of particles *a priori*. We propose a simple one-dimensional model to explain the optimal arrangement of particles as a function of the particle interaction potential and ...

Enzymatically Active Microspheres For Self-Propelled Colloidal Engines, 2017 CUNY City College of New York

#### Enzymatically Active Microspheres For Self-Propelled Colloidal Engines, Jungeun Park

*Dissertations and Theses*

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 ...

Memory Effects In Brownian Motion, Random Walks Under Confining Potentials, And Relaxation Of Quantum Systems, 2016 University of New Mexico

#### Memory Effects In Brownian Motion, Random Walks Under Confining Potentials, And Relaxation Of Quantum Systems, Matthew Chase

*Physics & Astronomy ETDs*

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 ...

Elasticity Of Cylindrical Black Holes, 2016 California Polytechnic State University, San Luis Obispo

#### Elasticity Of Cylindrical Black Holes, Conrad Pearson

*Physics*

Black holes are regions of strong gravity, and are often regarded as behaving like drops of fluid. When this line of thought is applied to cylindrical black holes (black cylinders), a mapping can be made between known instabilities for black cylinders and ordinary fluid cylinders. However, this known correlation is increasingly less accurate for lower spatial dimensions, and I seek to correct this discrepancy in this thesis. By considering soft solids instead of pure fluids, elastic energy can be included, which brings us closer to a direct comparison. In improving this mapping, it becomes possible to better understand the behavior ...

Large Scale Brownian Dynamics Simulation Of Dilute And Semidilute Polymeric Solutions, 2016 University of Tennessee, Knoxville

#### Large Scale Brownian Dynamics Simulation Of Dilute And Semidilute Polymeric Solutions, Amir Saadat

*Doctoral Dissertations*

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*(*N*_{b2}) [order *N* subscript b ...

Intermittency And Velocity Fluctuations In Hopper Flows Prone To Clogging, 2016 University of Pennsylvania

#### Intermittency And Velocity Fluctuations In Hopper Flows Prone To Clogging, C. C. Thomas, Douglas J. Durian

*Department of Physics Papers*

We study experimentally the dynamics of granular media in a discharging hopper. In such flows, there often appears to be a critical outlet size * D_{c}* such that the flow never clogs for

*. We report on the time-averaged velocity distributions, as well as temporal intermittency in the ensemble-averaged velocity of grains in a viewing window, for both*

**D > D**_{c}*and*

**D < D**_{c}*, near and far from the outlet. We characterize the velocity distributions by the standard deviation and the skewness of the distribution of vertical velocities. We propose a measure for intermittency based on the two-sample ...*

**D > D**_{c}The Effect Of Attractive Polymer-Nanoparticle Interactions On The Local Segmental Dynamics Of Polymer Nanocomposites, 2016 University of Tennessee, Knoxville

#### The Effect Of Attractive Polymer-Nanoparticle Interactions On The Local Segmental Dynamics Of Polymer Nanocomposites, Adam Prillaman Holt

*Doctoral Dissertations*

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 ...

Classical Transport In Disordered Systems, 2016 Graduate Center, City University of New York

#### Classical Transport In Disordered Systems, Antonios Papaioannou

*All Dissertations, Theses, and Capstone Projects*

This thesis reports on the manifestation of structural disorder on molecular transport and it consists of two parts. Part I discusses the relations between classical transport and the underlying structural complexity of the system. Both types of molecular diffusion, namely Gaussian and non-Gaussian are presented and the relevant time regimes are discussed. In addition the concept of structural universality is introduced and connected with the diffusion metrics. One of the most robust techniques for measuring molecular mean square displacements is magnetic resonance. This method requires encoding and subsequently reading out after an experimentally controlled time, a phase ϕ to the ...

Model For The Electrolysis Of Water And Its Use For Optimization, 2016 Georgia Institute of Technology

#### Model For The Electrolysis Of Water And Its Use For Optimization, Roger Lascorz, Javier E. Hasbun Dr

*Georgia Journal of Science*

The goal of this research was to study the optimization of the electrolysis of water both theoretically and experimentally. For accuracy, 3 hr experiments were made with measurements recorded every 15 min. The results show that a better model than the classical one is needed for water electrolysis. A new model that fits experimental data better is proposed. The results of this new model not only predict hydrogen production in electrolysis of water better, but show a way to predict gas production of any liquid as well as what voltage to use to optimize it.

Dynamics Of Discs In A Nematic Liquid Crystal, 2016 The University of Western Ontario

#### Dynamics Of Discs In A Nematic Liquid Crystal, Alena Antipova

*Electronic Thesis and Dissertation Repository*

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 ...