Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 9 of 9
Full-Text Articles in Physics
Mechanism Of Electric-Field-Induced Segregation Of Additives In A Liquid-Crystal Host, Lu Lu, Vassili Sergan, Philip J. Bos
Mechanism Of Electric-Field-Induced Segregation Of Additives In A Liquid-Crystal Host, Lu Lu, Vassili Sergan, Philip J. Bos
Philip J. Bos
The mechanism for electric-field-induced segregation of additives, containing a polar group, in a host liquid crystal is proposed. It is shown that the polarity of an applied dc electric field, or the frequency of an ac electric field, strongly influences the segregation of reactive monomers containing an ester group. An explanation of this result is offered based on the association of dissolved ions with polar groups of the reactive monomers. This association is considered to cause these types of additives to drift to the cell surface in the presence of an external electric field. The described mechanism can be applied …
Large-Scale Topological And Dynamical Properties Of The Internet, A Vazquez, R Pastor-Satorras, A Vespignani
Large-Scale Topological And Dynamical Properties Of The Internet, A Vazquez, R Pastor-Satorras, A Vespignani
Alessandro Vespignani
We study the large-scale topological and dynamical properties of real Internet maps at the autonomous system level, collected in a 3-yr time interval. We find that the connectivity structure of the Internet presents statistical distributions settled in a well-defined stationary state. The large-scale properties are characterized by a scale-free topology consistent with previous observations. Correlation functions and clustering coefficients exhibit a remarkable structure due to the underlying hierarchical organization of the Internet. The study of the Internet time evolution shows a growth dynamics with aging features typical of recently proposed growing network models. We compare the properties of growing network …
Statistical Theory Of Internet Exploration, L Dall'asta, I Alvarez-Hamelin, A Barrat, A Vazquez, A Vespignani
Statistical Theory Of Internet Exploration, L Dall'asta, I Alvarez-Hamelin, A Barrat, A Vazquez, A Vespignani
Alessandro Vespignani
The general methodology used to construct Internet maps consists in merging all the discovered paths obtained by sending data packets from a set of active computers to a set of destination hosts, obtaining a graphlike representation of the network. This technique, sometimes referred to as Internet tomography, spurs the issue concerning the statistical reliability of such empirical maps. We tackle this problem by modeling the network sampling process on synthetic graphs and by using a mean-field approximation to obtain expressions for the probability of edge and vertex detection in the sampled graph. This allows a general understanding of the origin …
The Gleamviz Computational Tool, A Publicly Available Software To Explore Realistic Epidemic Spreading Scenarios At The Global Scale, Wouter Van Den Broeck, Corrado Gioannini, Bruno Goncalves, Marco Quaggiotto, Vittoria Colizza, Alessandro Vespignani
The Gleamviz Computational Tool, A Publicly Available Software To Explore Realistic Epidemic Spreading Scenarios At The Global Scale, Wouter Van Den Broeck, Corrado Gioannini, Bruno Goncalves, Marco Quaggiotto, Vittoria Colizza, Alessandro Vespignani
Alessandro Vespignani
Background: Computational models play an increasingly important role in the assessment and control of public health crises, as demonstrated during the 2009 H1N1 influenza pandemic. Much research has been done in recent years in the development of sophisticated data-driven models for realistic computer-based simulations of infectious disease spreading. However, only a few computational tools are presently available for assessing scenarios, predicting epidemic evolutions, and managing health emergencies that can benefit a broad audience of users including policy makers and health institutions. Results: We present "GLEaMviz", a publicly available software system that simulates the spread of emerging human-to-human infectious diseases across …
Shape Selection Of Twist-Nematic-Elastomer Ribbons, Yoshiki Sawa, Fangfu Ye, Kenji Urayama, Toshikazu Takigawa, Vianney Gimenez-Pinto, Robin Selinger, Jonathan Selinger
Shape Selection Of Twist-Nematic-Elastomer Ribbons, Yoshiki Sawa, Fangfu Ye, Kenji Urayama, Toshikazu Takigawa, Vianney Gimenez-Pinto, Robin Selinger, Jonathan Selinger
Robin Selinger
How microscopic chirality is reflected in macroscopic scale to form various chiral shapes, such as straight helicoids and spiral ribbons, and how the degree of macroscopic chirality can be controlled are a focus of studies on the shape formation of many biomaterials and supramolecular systems. This article investigates both experimentally and theoretically how the chiral arrangement of liquid crystal mesogens in twist-nematic-elastomer films induces the formation of helicoids and spiral ribbons because of the coupling between the liquid crystalline order and the elasticity. It is also shown that the pitch of the formed ribbons can be tuned by temperature variation. …
Modeling Bursts And Heavy Tails In Human Dynamics, Alexei Vázquez, João Gama Oliveira, Zoltán Dezsö, Kwang-Il Goh, Imre Kondor, Albert-László Barabási
Modeling Bursts And Heavy Tails In Human Dynamics, Alexei Vázquez, João Gama Oliveira, Zoltán Dezsö, Kwang-Il Goh, Imre Kondor, Albert-László Barabási
Albert-László Barabási
No abstract provided.
Universal Conductivity Curve For A Plane Containing Random Holes., E. J. Garboczi, M. F. Thorpe, M. S. Devries, Anthony Roy Day
Universal Conductivity Curve For A Plane Containing Random Holes., E. J. Garboczi, M. F. Thorpe, M. S. Devries, Anthony Roy Day
Anthony Roy Day
This paper examines the general percolation problem of cutting randomly centered insulating holes in a two-dimensional conducting sheet, and explores how the electrical conductivity sigma decreases with the remaining area fraction. This problem has been studied in the past for circular, square, and needlelike holes, using both computer simulations and analog experiments. In this paper, we extend these studies by examining cases where the insulating hole is of arbitrary shape, using digital-image-based numerical techniques in conjunction with the Y- [nabla] algorithm. We find that, within computational uncertainty, the scaled percolation threshold, xc=nc=5.9±0.4, is a universal quantity for all the cases …
Spectral Dimensionality Of Random Superconducting Networks, Anthony Roy Day, W. Xia, M. F. Thorpe
Spectral Dimensionality Of Random Superconducting Networks, Anthony Roy Day, W. Xia, M. F. Thorpe
Anthony Roy Day
We compute the spectral dimensionality d-tilde of random superconducting-normal networks by directly examining the low-frequency density of states at the percolation threshold. We find that d-tilde=4.1±0.2 and 5.8±0.3 in two and three dimensions, respectively, which confirms the scaling relation d-tilde=2d/(2-s/ nu ), where s is the superconducting exponent and nu the correlation-length exponent for percolation. We also consider the one-dimensional problem where scaling arguments predict, and our numerical simulations confirm, that d-tilde=0. A simple argument provides an expression for the density of states of the localized high-frequency modes in this special case. We comment on the connection between our calculations …
Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay
Splay Rigidity In The Diluted Central Force Elastic Network, Anthony Roy Day, A.-M. S. Tremblay, R. R. Tremblay
Anthony Roy Day
A Comment on the Letter by Wang and Harris, Phys. Rev. Lett. 55, 2459 (1985).