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Resultados filtrados por Publicador: Universidade Cornell

‣ Scaling and Selection in Cellular Structures and Living Polymers

Mukamel, David
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/02/1995 Português
Relevância na Pesquisa
456.8204%
The dynamical behavior of two types of non-equilibrium systems is discussed: $(a)$ two-dimensional cellular structures, and $(b)$ living polymers. Simple models governing their evolution are introduced and steady state distributions (cell side in the case of cellular structures and length in the case of living polymers) are calculated. In both cases the models possess a one parameter family of steady state distributions. Selection mechanism by which a particular distribution is dynamically selected is discussed.; Comment: 12 pages, 2 figures, two seminars presented at the 1994 Les Houches Summer School ``Fluctuating Geometries in Statistical Mechanics and Field Theory.'' (also available at http://xxx.lanl.gov/lh94/)

‣ Numerical calculations of effective elastic properties of two cellular structures

Tuncer, Enis
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/04/2004 Português
Relevância na Pesquisa
464.5292%
Young's moduli of regular two-dimensional truss-like and eye-shape-like structures are simulated by using the finite element method. The structures are the idealizations of soft polymeric materials used in the electret applications. In the simulations size of the representative smallest units are varied, which changes the dimensions of the cell-walls in the structures. A power-law expression with a quadratic as the exponential term is proposed for the effective Young's moduli of the systems as a function of the solid volume fraction. The data is divided into three regions with respect to the volume fraction; low, intermediate and high concentrations. The parameters of the proposed power-law expression in each region are later represented as a function of the structural parameters, unit-cell dimensions. The presented expression can be used to predict structure/property relationship in materials with similar cellular structures. It is observed that the structures with volume fractions of solid higher than 0.15 exhibit the importance of the cell-wall thickness contribution in the elastic properties. The cell-wall thickness is the most significant factor to predict the effective Young's modulus of regular cellular structures at high volume fractions of solid. At lower concentrations of solid...

‣ Analysis of Poisson Networks and Their Relation with Random Cellular Structures

Karimipour, V.; Saaidi, Kh.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/03/1996 Português
Relevância na Pesquisa
449.71785%
We perform a detailed analysis of the statistical properties of Poisson networks and show that the metric and topological properties of random cellular structures, can not be derived from simple models of random networks based on a poisson point distribution [1]. In particular we show that Lewis and Aboav-Wieare laws are not obeyed in these network.; Comment: 17 pages , Latex , 3 Figures available upon request

‣ Compliant Pressure Actuated Cellular Structures

Pagitz, Markus
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
456.8204%
A novel concept for pressure actuated cellular structures that can change their shape between any two given one-dimensional functions was published by Pagitz et al 2012 Bioinspir. Biomim. 7. However, the underlying computational framework is limited to two cell rows and assumes frictionless cell corner hinges. This article extends previous work by taking into account an arbitrary number of cell rows, hinge eccentricities and rotational prings at hinges. Hence it is possible to design compliant pressure actuated cellular structures that can change their shape between any given set of one-dimensional functions. Furthermore, a potential based optimization approach is introduced that reduces the number of iterations by an order of magnitude.; Comment: 24 pages, 10 figures

‣ Hierarchical Cellular Structures in High-Capacity Cellular Communication Systems

Jain, R. K.; Katiyar, Sumit; Agrawal, N. K.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/10/2011 Português
Relevância na Pesquisa
456.978%
In the prevailing cellular environment, it is important to provide the resources for the fluctuating traffic demand exactly in the place and at the time where and when they are needed. In this paper, we explored the ability of hierarchical cellular structures with inter layer reuse to increase the capacity of mobile communication network by applying total frequency hopping (T-FH) and adaptive frequency allocation (AFA) as a strategy to reuse the macro and micro cell resources without frequency planning in indoor pico cells [11]. The practical aspects for designing macro- micro cellular overlays in the existing big urban areas are also explained [4]. Femto cells are inducted in macro / micro / pico cells hierarchical structure to achieve the required QoS cost effectively.; Comment: 7 pages, 8 figures, International Journal

‣ Sine-Gordon Solitons, Kinks and Breathers as Physical Models of Nonlinear Excitations in Living Cellular Structures

Ivancevic, Vladimir G.; Ivancevic, Tijana T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 02/05/2013 Português
Relevância na Pesquisa
455.48875%
Nonlinear space-time dynamics, defined in terms of celebrated 'solitonic' equations, brings indispensable tools for understanding, prediction and control of complex behaviors in both physical and life sciences. In this paper, we review sine-Gordon solitons, kinks and breathers as models of nonlinear excitations in complex systems in physics and in living cellular structures, both intra-cellular (DNA, protein folding and microtubules) and inter-cellular (neural impulses and muscular contractions). Key words: Sine-Gordon solitons, kinks and breathers, DNA, Protein folding, Microtubules, Neural conduction, Muscular contraction; Comment: 55 pages, 11 figures, Latex. arXiv admin note: text overlap with arXiv:quant-ph/9512021, arXiv:hep-ph/9505401, arXiv:nlin/0205044, arXiv:cond-mat/0209427, arXiv:cond-mat/9906020, arXiv:patt-sol/9809011 by other authors

‣ Cellular structures using $\textbf{U}_q$-tilting modules

Andersen, Henning Haahr; Stroppel, Catharina; Tubbenhauer, Daniel
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
453.2903%
We use the theory of $\textbf{U}_q$-tilting modules to construct cellular bases for centralizer algebras. Our methods are quite general and work for any quantum group $\textbf{U}_q$ attached to a Cartan matrix and include the non semi-simple cases for $q$ being a root of unity and ground fields of positive characteristic. Our approach also generalize to certain categories containing infinite-dimensional modules. As an application, we recover several known cellular structures (which all fit into our general set-up) as we illustrate in a list of examples.; Comment: 51 pages, lots of figures, comments welcome, some typos corrected

‣ Design of Pressure Actuated Cellular Structures

Pagitz, Markus
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
464.15207%
A novel concept for pressure actuated cellular structures was published in Pagitz et al 2012 Bioinspir. Biomim. 7. The corresponding mathematical foundation for the simulation and optimization of compliant cellular structures with eccentric cell corner hinges was published in Pagitz 2015 arXiv:1403.2197. The aim of this article is threefold: First, analytical expressions for optimal materials of compliant cellular structures with identical properties are derived as a function of cell sizes. It is shown that cellular structures can be made from either a large, small number of highly, lowly pressurized cells that consist of a stiff, soft material. Second, extensions to the previously published numerical model are presented and their application ranges are determined. Third, end cap designs for prismatic cells are developed that can withstand substantial differential pressures while being flexible enough to allow large cross sectional shape changes. Furthermore, a manufacturing approach that is based on cytoskeletons is presented.; Comment: 18 pages, 15 figures

‣ Identification of large-scale cellular structures on the Sun based on the SDO and PSPT data

Efremov, V. I.; Parfinenko, L. D.; Solovev, A. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/12/2014 Português
Relevância na Pesquisa
453.24797%
Three independent sets of data: i). series of filtergrams obtained in line CaII K (393.416 nm) with the ground-based telescope Precision Solar Photometric Telescope (PSPT) of Mauna Loa Solar Observatory; ii). series of filtergrams of Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO) in {\lambda}160 nm and iii). series of magnetograms of Helioseismic and Magnetic Imager (HMI) of SDO have been processed to reveal reliably the existence of spatial cellular structures on the solar photosphere at scale about of 300 arcsec. This scale is intermediate between supergranules and giant cells (~30,000 and ~300,000 kilometers across, respectively). To identify the different spatial structures the tens of two-dimensional power spectra (2DFFT) have been averaged. For one-dimensional photometric cross sections of frames, the Fourier power spectra (FFT) and wavelet transforms (Morlet 5-th order) have been calculated.; Comment: 10 pages, 6 figures. Accepted in Astrophys Space Sci