1,720,993 research outputs found
A comprehensive electro-magneto-elastic buckling and bending analyses of three-layered doubly curved nanoshell, based on nonlocal three-dimensional theory
No full textThe present paper studies the three-dimensional magneto-electro-elastic bending and buckling analyses of three-layered doubly curved nanoshells based on nonlocal elasticity theory. The kinematic relations are developed based on two-variable sinusoidal transverse shear and thickness deformation theory. The transverse deflection is decomposed into bending, shear and thickness deformation components by using a two-variable sinusoidal shear deformation theory. The nanoshell is subjected to in-plane mechanical, electrical and magnetic loads in which these forces are accounted as external works in constitutive relations for buckling analysis. This introduces a variable transverse displacement along the thickness direction. The principle of virtual work is used to derive the governing equations of bending and buckling. Numerical results are obtained based on Navier's technique for simply-supported boundary conditions. A parametric analysis is performed to investigate the influence of the nonlocal parameter, the applied electric and magnetic potentials on the magneto-electro-elastic bending and buckling responses of doubly curved nanoshells
Mechanical stress and deformation analyses of pressurized cylindrical shells based on a higher-order modeling
Full text linkIn this research, mechanical stress, static strain and deformation analyses of a cylindrical pressure vessel subjected to mechanical loads are presented. The kinematic relations are developed based on higher-order sinusoidal shear deformation theory. Thickness stretching formulation is accounted for more accurate analysis. The total transverse deflection is divided into bending, shear and thickness stretching parts in which the third term is responsible for change of deflection along the thickness direction. The axisymmetric formulations are derived through principle of virtual work. A parametric study is presented to investigate variation of stress and strain components along the thickness and longitudinal directions. To explore effect of thickness stretching model on the static results, a comparison between the present results with the available results of literature is presented. As an important output, effect of micro-scale parameter is studied on the static stress and strain distributio
A comprehensive vibration analysis of rotating truncated sandwich conical microshells including porous core and GPL-reinforced face-sheets
No full textThe first-order shear deformation theory (FSDT) and modified couple stress theory (MCST) are employed in this paper to investigate the free vibrational behavior of rotating truncated conical sandwich microshells. It is assumed that the sandwich microshell is made of polymer, the core is porous, and two face sheets are reinforced with graphene nanoplatelets (GPLs). To compute the effective mechanical properties of the face sheets, the rule of mixture and Halpin-Tsai model are utilized. The equations of motion are derived using Hamilton's principle incorporating the centrifugal acceleration, the Coriolis acceleration, and the initial hoop tension. To solve the governing equations in the circumferential and meridional directions, a trigonimetric functions and the differential quadrature method (DQM) are utilized, respectively. Accuracy and convergence of the presented solution are verified, and the influence of various parameters on the backward and forward frequencies of the rotating truncated conical sandwich microshells are investigated, including different boundary conditions, geometrical characteristics of the microshell, rotational speed, material length scale parameter, porosity parameter, distribution pattern of the pores, and also mass fraction, dispersion pattern and geometrical characteristics of the GPLs (thickness-to-length and aspect ratios)
Observer-Based Fuzzy Adaptive Dynamic Surface Control of Uncertain Nonstrict Feedback Systems with Unknown Control Direction and Unknown Dead-Zone
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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