From Critical Behavior To Catastrophic Runaways: Comparing Sheared Granular Materials With Bulk Metallic Glasses, 2019 University of Illinois at Urbana-Champaign

#### From Critical Behavior To Catastrophic Runaways: Comparing Sheared Granular Materials With Bulk Metallic Glasses, Alan A. Long, Dmitry Denisov, Peter Schall, Todd C. Hufnagel, Xiaojun Gu, Wendelin J. Wright, Karin A. Dahmen

*Faculty Journal Articles*

The flow of granular materials and metallic glasses is governed by strongly correlated, avalanche-like deformation. Recent comparisons focused on the scaling regimes of the small avalanches, where strong similarities were found in the two systems. Here, we investigate the regime of large avalanches by computing the temporal profile or “shape” of each one, i.e., the time derivative of the stress-time series during each avalanche. We then compare the experimental statistics and dynamics of these shapes in granular media and bulk metallic glasses. We complement the experiments with a mean-field model that predicts a critical size beyond which avalanches turn ...

Force Oscillations Distort Avalanche Shapes, 2019 University of Illinois at Urbana-Champaign

#### Force Oscillations Distort Avalanche Shapes, Louis W. Mcfaul, Wendelin J. Wright, Jordan Sickle, Karin A. Dahmen

*Faculty Journal Articles*

Contradictory scaling behavior in experiments testing the principle of universality may be due to external oscillations. Thus, the effect of damped oscillatory external forces on slip avalanches in slowly deformed solids is simulated using a mean-field model. Akin to a resonance effect, oscillatory driving forces change the dynamics of avalanches with durations close to the oscillation period. This problem can be avoided by tuning mechanical resonance frequencies away from the range of the inverse avalanche durations. The results provide critical guidance for experimental tests for universality and a quantitative understanding of avalanche dynamics under a wide range of driving conditions.

Inference Of Language Functional Network In Healthy, Cancerous And Bilingual Brains By Fmri And Network Modeling, 2019 The Graduate Center, City University of New York

#### Inference Of Language Functional Network In Healthy, Cancerous And Bilingual Brains By Fmri And Network Modeling, Qiongge Li

*All Dissertations, Theses, and Capstone Projects*

We study the underlying mechanism by which language processing occurs in the human brain using inference methods on functional magnetic resonance imaging data. The data analyzed stems from several cohorts of subjects; a monolingual group, a bilingual group, a healthy control group and one diseased case. We applied a complex statistical inference pipeline to determine the network structure of brain components involved with language. This healthy network reveals a fully connected triangular relationship between the pre-Supplementary Motor Area (pre-SMA), the Broca's Area (BA), and the ventral Pre-Motor Area (PreMA) in the left hemisphere. This "triangle'' shows consistently in all ...

Stability And Application Of The K-Core Dynamical Model To Biological Networks, 2019 The Graduate Center, City University of New York

#### Stability And Application Of The K-Core Dynamical Model To Biological Networks, Francesca Beatrice Arese Lucini

*All Dissertations, Theses, and Capstone Projects*

The objective of the dissertation is to illustrate the importance of the k-core dynamical model, by first presenting the stability analysis of the nonlinear k-core model and compare its solution to the most widely used linear model. Second, I show a real world application of the k-core model to describe properties of neural networks, specifically, the transition from conscious to subliminal perception.

Development Of A 1-Dimensional Data Assimilation To Determine Temperature And Relative Humidity Combining Raman Lidar Backscatter Measurements And A Reanalysis Model, 2019 The University of Western Ontario

#### Development Of A 1-Dimensional Data Assimilation To Determine Temperature And Relative Humidity Combining Raman Lidar Backscatter Measurements And A Reanalysis Model, Shayamila N. Mahagammulla Gamage

*Electronic Thesis and Dissertation Repository*

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 ...

Application Of The Optimal Estimation Method (Oem) To Retrieve Relative Humidity From Raman Lidar Backscatter Measurements., 2019 Department of Physics and Astronomy, The University of Western Ontario, London, Canada

#### Application Of The Optimal Estimation Method (Oem) To Retrieve Relative Humidity From Raman Lidar Backscatter Measurements., Shayamila N. Mahagammulla Gamage, Robert Sica, Alexander Haefele

*Western Research Forum*

Accurate measurements of relative humidity (RH) vertical profiles in the atmosphere is important for understanding the earth's weather and the climate system. RH represent the current state of the water vapor in the atmosphere with respect to the ambient air related to saturation. Even minor changes of the RH in the lower atmosphere has a large impact of the global circulation and cloud formation. Due to its high variability RH measurements in the lower atmosphere is significantly challenging. Raman lidar is one of the potential tools that can provide vertical profiles of RH. Typically, temperature and water vapor mixing ...

Emergent Critical Properties In Liquid-Gas Transition And Single Dislocations In Solid He4, 2019 Graduate Center, City University of New York

#### Emergent Critical Properties In Liquid-Gas Transition And Single Dislocations In Solid He4, Max Yarmolinsky

*All Dissertations, Theses, and Capstone Projects*

My research focuses on the analytical and numerical study of seemingly completely different systems - the classical critical point of the liquid-gas transition and a quantum topological defect (dislocation) in solid Helium-4. The unifying theme, though, is *Emergence* - the appearance of unexpected qualities at large distance and time scales in these systems. Our results resolve the long standing controversy about the nature of the liquid-gas criticality by showing with high confidence that it is the same as that of Ising ferromagnet. In solid ^{4}He, a quantum *superclimbing* dislocation, which is expected to be violating space-time symmetry according to the elementary ...

Hydrodynamics Of Smectic Liquid Crystal Films, 2019 University of Colorado, Boulder

#### Hydrodynamics Of Smectic Liquid Crystal Films, Eric Minor

*Undergraduate Honors Theses*

Smectic A and C liquid crystals are capable of forming incredibly thin films, discretized by the number of molecular layers. This property makes liquid crystal films ideal for studying 2D hydrodynamics, a field of great interest both due to its fundamental importance to physics and because of its applications to biological systems. The phospholipid bilayer which makes up cell membranes is itself an ideal 2D fluid as it consists of only two layers of phospholipids, however cell membranes are incredibly small and difficult to work worth. Liquid crystal films can be several millimeters across and stable for long periods of ...

Photo-Tunable Compression And Realization Of Colloidal Spin Ice In Skyrmion Arrays In Chiral Nematic Liquid Crystals, 2019 University of Colorado, Boulder

#### Photo-Tunable Compression And Realization Of Colloidal Spin Ice In Skyrmion Arrays In Chiral Nematic Liquid Crystals, Yuhan Wang

*Undergraduate Honors Theses*

Topological solitons are field configurations that are important to theorists in particle physics and cosmology, but recently have been studied in condensed matter systems with reconfigurable fields, like chiral magnets and liquid crystals. In these communities, there is a strong interest in studying and understanding the dynamic behavior of these solitons, many examples of which I will present in this thesis. This includes exploring the dynamic motion and patterning behavior of large number-densities of two-dimensional topological structures called skyrmions with external stimulation by light. With these techniques we can realize for the first time a colloidal spin ice system in ...

Practical Chaos: Using Dynamical Systems To Encrypt Audio And Visual Data, 2019 Scripps College

#### Practical Chaos: Using Dynamical Systems To Encrypt Audio And Visual Data, Julia Ruiter

*Scripps Senior Theses*

Although dynamical systems have a multitude of classical uses in physics and applied mathematics, new research in theoretical computer science shows that dynamical systems can also be used as a highly secure method of encrypting data. Properties of Lorenz and similar systems of equations yield chaotic outputs that are good at masking the underlying data both physically and mathematically. This paper aims to show how Lorenz systems may be used to encrypt text and image data, as well as provide a framework for how physical mechanisms may be built using these properties to transmit encrypted wave signals.

Universality Class Of Explosive Percolation In Barabási-Albert Networks, 2019 Old Dominion University

#### Universality Class Of Explosive Percolation In Barabási-Albert Networks, Habib E. Islam, M. K. Hassan

*Physics Faculty Publications*

In this work, we study explosive percolation (EP) in Barabási-Albert (BA) network, in which nodes are born with degree *k = m*, for both product rule (PR) and sum rule (SR) of the Achlioptas process. For *m* = 1 we find that the critical point t_{c} = 1 which is the maximum possible value of the relative link density t; Hence we cannot have access to the other phase like percolation in one dimension. However, for *m* > 1 we find that t_{c} decreases with increasing *m* and the critical exponents *ν*,* α*,* β* and *γ* for *m* > 1 are found to ...

The Solvation Energy Of Ions In A Stockmayer Fluid, 2019 Michigan Technological University

#### The Solvation Energy Of Ions In A Stockmayer Fluid, Cameron John Shock

*Dissertations, Master's Theses and Master's Reports*

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 ...

Matlab Programs, 2018 Selected Works

#### Matlab Programs

*David D Nolte*

*Introduction to Modern Dynamics*

Application Of Graphical Models In Protein-Protein Interactions And Dynamics, 2018 University of Massachusetts Boston

#### Application Of Graphical Models In Protein-Protein Interactions And Dynamics, Amir Vajdi Hoojghan

*Graduate Doctoral Dissertations*

Every organism contains a few hundred to thousands of proteins. A protein is made of a sequence of molecular building blocks named amino acids. Amino acids will be referred to as residues. Every protein performs one or more functions in the cell. In order for a protein to do its job, it requires to bind properly to other partner proteins. Many genetic diseases such as cancer are caused by mutations (changes) of specific residues which cause disturbances in the functions of those proteins.

The problem of prediction of protein binding site is a crucial topic in computational biology. A protein ...

Fatigue Performance And Shear Demand Distributions Of Clustered Shear Connectors In Composite Bridge Girders, 2018 University of Arkansas, Fayetteville

#### Fatigue Performance And Shear Demand Distributions Of Clustered Shear Connectors In Composite Bridge Girders, Brian David Hillhouse

*Theses and Dissertations*

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 ...

Conforming Nanoparticle Sheets To Surfaces With Gaussian Curvature, 2018 Marshall University

#### Conforming Nanoparticle Sheets To Surfaces With Gaussian Curvature, Noah P. Mitchell, Remington L. Carey, Jelani Hannah, Yifan Wang, Sean P. Mcbride, Xiao-Min Lin, Heinrich M. Jaeger

*Physics Faculty Research*

Nanoparticle monolayer sheets are ultrathin inorganic-organic hybrid materials that combine highly controllable optical and electrical properties with mechanical exibility and remarkable strength. Like other thin sheets, their low bending rigidity allows them to easily roll into or conform to cylindrical geometries. Nanoparticle monolayers not only can bend, but also cope with strain through local particle rearrangement and plastic deformation. This means that, unlike thin sheets such as paper or graphene, nanoparticle sheets can much more easily conform to surfaces with com- plex topography characterized by non-zero Gaussian curvature, like spherical caps or saddles. Here, we investigate the limits of nanoparticle ...

Magnetoelectric Memory Cells With Domain-Wall-Mediated Switching, 2018 University of Nebraska - Lincoln

#### Magnetoelectric Memory Cells With Domain-Wall-Mediated Switching, Kirill Belashchenko, Oleg Tchernyshyov, Alexey Kovalev, Dmitri Nikonov

*Kirill Belashchenko Publications*

A magnetoelectric memory cell with domain - wall - mediated switching is implemented using a split gate architecture . The split gate architecture allows a domain wall to be trapped within a magnetoelectric antiferromagnetic ( MEAF ) active layer . An extension of this architecture applies to multiple gate linear arrays that can offer advantages in memory density , programmability , and logic functionality . Applying a small anisotropic in - plane shear strain to the MEAF can block domain wall precession to improve reliability and speed of switching

Reversible Motion In A Contact Line, 2018 California Polytechnic State University, San Luis Obispo

#### Reversible Motion In A Contact Line, Audrey Profeta, Esmeralda Orozco, Juan A. Ortiz Salazar, Dani Medina, Nathan C. Keim

*STAR (STEM Teacher and Researcher) Presentations*

When a body of liquid sits on a surface, an irregular border between the wet and dry regions of the surface exists, called the contact line. Driving this contact line back and forth repeatedly can change its shape.We use a syringe pump to cyclically infuse and withdraw a predetermined volume of water, and take photos of the contact line after each cycle. Comparing these images to each other determines if the contact line is returning to the same shape. We find that below a critical value of infused volume, after many cycles the contact line reaches a steady state ...

A Network Theoretical Approach To Real-World Problems: Application Of The K-Core Algorithm To Various Systems, 2018 The Graduate Center, City University of New York

#### A Network Theoretical Approach To Real-World Problems: Application Of The K-Core Algorithm To Various Systems, Kate Burleson-Lesser

*All Dissertations, Theses, and Capstone Projects*

The study of complex networks is, at its core, an exploration of the mechanisms that control the world in which we live at every scale, from particles no bigger than a grain of sand and amino acids that comprise proteins, to social networks, ecosystems, and even countries. Indeed, we find that, regardless of the physical size of the network's components, we may apply principles of complex network theory, thermodynamics, and statistical mechanics to not only better understand these specific networks, but to formulate theories which may be applied to problems on a more general level. This thesis explores several ...

Vibrating-Wire Rheometry, 2018 The University of Western Ontario

#### Vibrating-Wire Rheometry, Cameron C. Hopkins

*Electronic Thesis and Dissertation Repository*

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 ...