196,764 research outputs found
Step-by-step integration for fractional operators
No full textn this paper, an approach based on the definition of the Riemann–Liouville fractional op- erators is proposed in order to provide a different discretisation technique as alternative to the Grünwald–Letnikov operators. The proposed Riemann–Liouville discretisation consists of performing step-by-step integration based upon the discretisation of the function f(t). It has been shown that, as f(t) is discretised as stepwise or piecewise function, the Riemann– Liouville fractional integral and derivative are governing by operators very similar to the Grünwald–Letnikov operators.
In order to show the accuracy and capabilities of the proposed Riemann–Liouville discreti- sation technique and the Grünwald–Letnikov discrete operators, both techniques have been applied to: unit step functions, exponential functions and sample functions of white noise
Métrica y poética de Antonio Colinas [RESEÑA]
No full textReseña de Martínez Cantón, Clara Isabel
Métrica y poética de Antonio Colinas. Sevilla: Padilla Libros, 2011. 336 pp. (ISBN: 978- 84-8434-553-4
Fractional viscoelastic behaviour under stochastic temperature process
No full textThis paper deals with the mechanical behaviour of a linear viscoelastic material modelled by a fractional Maxwell model and subject to a Gaussian stochastic temperature process. Two methods are introduced to evaluate the response in terms of strain of a material under a deterministic stress and subjected to a varying temperature. In the first approach the response is determined making the material parameters change at each time step, due to the temperature variation. The second method, takes advantage of the Time–Temperature Superposition Principle to lighten the calculations. In this regard, a stochastic characterisation for the Time–Temperature Superposition Principle method is proposed for a Gaussian stochastic temperature process. A numerical example, based on experimental data of an epoxy resin at different temperatures, is presented to simulate a creep test under a Gaussian stochastic temperature process with assigned power spectral density function. Comparison between the two considered methods is shown, and the accuracy of the proposed stochastic characterisation is assesse
Evaluation of the temperature effect on the fractional linear viscoelastic model for an epoxy resin
No full textThe paper deals with the evolution of the parameters of a fractional model for di↵erent values of temperature. An experimental campaign has been performed on epoxy resin at di↵erent levels of temperature. It is shown that epoxy resin is very sensitive to the temperature
Caracterización de rasgos funcionales de Parkia panurensis “pashaco colorado” en colinas bajas y altas
No full textLa investigación busco saber ¿Cuáles serían las características de los rasgos funcionales de
Parkia panurensis “pashaco colorado” en colinas bajas y altas? con el propósito de determinar
la cantidad de individuos por hectárea, la morfometría del individuo y su copa, las diferencias
en tamaño foliar, área foliar y área foliar específica, así como también la diferencia de la
densidad básica. Cubriendo un área de 23,02 ha del BRUNAS, evaluándose 14 UM de 0,05 ha
en cada bloque, usando para ello el método descriptivo y transversal, siendo necesario usar las
propuestas de varios autores para el logro de cada objetivo propuesto. Concluyéndose, con
6,89 ±0,99 árb./ha en colina baja y 7,02±1,77 árb./ha en colina alta. La Altura máxima 75%
en el estrato medio de colinas altas y 42,86% en el estrato Superior de colinas bajas. El
diámetro en colina baja es superior en 10-20 cm con el 42,85 % y en colina alta es de 20-30
cm con el 25%. En altura de copa el promedio es 9,57 m en colina baja y 6,50 m en colina
alta. Los parámetros de copa muestran sutiles diferencias en colinas bajas y altas. Y en cuanto
a los rasgos foliares y la densidad básica de la madera no existen diferencias marcada
Fractional viscoelastic beam under torsion
No full textThis paper introduces a study on twisted viscoelastic beams, having considered fractional calculus to capture the viscoelastic behaviour. Further another novelty of this paper is extending a recent numerical approach, labelled line elementless method (LEM), to viscoelastic beams. The latter does not require any discretization neither in the domain nor in the boundary. Some numerical applications have been reported to demonstrate the efficiency and accuracy of the method
Fractional characteristic times and dissipated energy in fractional linear viscoelasticity
No full textIn fractional viscoelasticity the stress-strain relation is a differential equation with non-integer operators (derivative or integral). Such constitutive law is able to describe the mechanical behavior of several materials, but when fractional operators appear, the elastic and the viscous contribution are inseparable and the characteristic times (relaxation and retardation time) cannot be defined. This paper aims to provide an approach to separate the elastic and the viscous phase in the fractional stress-strain relation with the aid of an equivalent classical model (Kelvin-Voigt or Maxwell). For such equivalent model the parameters are selected by an optimization procedure. Once the parameters of the equivalent model are defined, characteristic times of fractional viscoelasticity are readily defined as ratio between viscosity and stiffness.In the numerical applications, three kinds of different excitations are considered, that is, harmonic, periodic, and pseudo-stochastic. It is shown that, for any periodic excitation, the equivalent models have some important features: (i) the dissipated energy per cycle at steady-state coincides with the Staverman-Schwarzl formulation of the fractional model, (ii) the elastic and the viscous coefficients of the equivalent model are strictly related to the storage and the loss modulus, respectively
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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