1,721,039 research outputs found
Buckling behavior of nanobeams placed in electromagnetic field using shifted Chebyshev polynomials-based Rayleigh-Ritz method
Get PDFIn the present investigation, the buckling behavior of Euler-Bernoulli nanobeam, which is placed in an electro-magnetic field, is investigated in the framework of Eringen’s nonlocal theory. Critical buckling load for all the classical boundary conditions such as “Pined-Pined (P-P), Clamped-Pined (C-P), Clamped-Clamped (C-C), and Clamped-Free (C-F)" are obtained using shifted Chebyshev polynomials-based Rayleigh-Ritz method. The main advantage of the shifted Chebyshev polynomials is that it does not make the system ill-conditioning with the higher number of terms in the approximation due to the orthogonality of the functions. Validation and convergence studies of the model have been carried out for different cases. Also, a closed-form solution has been obtained for the “Pined-Pined (P-P)" boundary condition using Navier’s technique, and the numerical results obtained for the “Pined-Pined (P-P)" boundary condition are validated with a closed-form solution. Further, the effects of various scaling parameters on the critical buckling load have been explored, and new results are presented as Figures and Tables. Finally, buckling mode shapes are also plotted to show the sensitiveness of the critical buckling load
Vibration characteristics of nanobeam with exponentially varying flexural rigidity resting on linearly varying elastic foundation using differential quadrature method
No full textThe target of the present research is to analyze the free vibration of non-uniform nanobeam resting on variable Winkler elastic foundation using the differential quadrature method. Non-uniformity in nanobeam is taken along the flexural rigidity, and the nanobeam is modeled with linearly varying Winkler elastic foundation. Eringen's nonlocal theory is employed in Euler-Bernoulli beam theory for different scaling parameters concerning the boundary conditions are explored. In order to illustrate the efficiency and accuracy of the method, the convergence study is carried out, and the obtained results are validated with known results in particular cases showing excellent agreement. Further, the sensitivity analysis of frequency parameters is carried out to examine the response of various scaling parameters
Dynamical behavior of nanobeam embedded in constant, linear, parabolic, and sinusoidal types of Winkler elastic foundation using first-Order nonlocal strain gradient model
No full textIn this research, the differential quadrature method is employed to investigate the nonlocal vibration of nanobeam resting on various types of Winkler elastic foundations such as constant, linear, parabolic, and sinusoidal types. The nanobeam is modeled with Winkler elastic foundation considering the elastic coefficient varying along the axis of the nanobeam. Within the framework of Euler-Bernoulli beam theory, first order strain gradient model is incorporated to compute the frequency parameters for Hinged-Hinged (H-H) and Clamped-Hinged (C-H) boundary conditions. A convergence study is also performed to demonstrate the efficiency, adequacy, and reliability of the method. Further, the results are compared with available data of previously published research in special cases showing robust agreement. Likewise, the effects of the nonlocal parameter, strain gradient parameter, non-uniform parameters, and Winkler modulus parameter on the frequency parameters are studied comprehensively
Stability analysis of single-walled carbon nanotubes embedded in winkler foundation placed in a thermal environment considering the surface effect using a new refined beam theory
No full textThis article is devoted to investigate the stability of different types of Single Walled Carbon Nanotubes (SWCNTs) such as zigzag, chiral, and armchair types which are rested in Winkler elastic foundations exposing to both the low and high temperature environments. Also, the Surface effects which include surface energy and surface residual stresses, are taken into consideration in this study. It may be noted that the surface energy aids in the increase of the flexural rigidity whereas the surface residual stresses act as distributed transverse load. Further, the proposed model is developed by considering a novel refined beam theory namely one variable first order shear deformation beam theory along with the Hamilton’s principle. Navier’s method has been implemented to find out the critical buckling loads for Hinged-Hinged (H-H) boundary condition for zigzag, chiral, and armchair types of SWCNTs. A parametric study is also conducted to report the influence of various scaling parameters like small scale parameters, change in temperature, Winkler stiffness, and length to diameter ratio on critical buckling loads. Also, the present model is validated by comparing the results with other published work
A novel fractional nonlocal model and its application in buckling analysis of Euler-Bernoulli nanobeam
No full textThe present study aims to analyze the buckling behavior of Euler- Bernoulli nanobeam in conjunction with a novel fractional nonlocal model namely conformable fractional nonlocal model. Fractional models are getting more popular among the researchers because of its applicability and fixability to handle many complex physical phenomena which are not possible to model with integer operators. Also, the main advantage of fractional models over integer model is its applicability to handle both the integer and noninteger operators which makes it much more flexible in term of real-world application. In this regards, the nonlocal constitutive relation is developed in conjunction with conformable fractional derivatives and fractional strain energy to analyze the buckling behavior of Euler-Bernoulli Nanobeam. In this study, the Simply Supported-Simply Supported (SS), Clamped-Simply Supported, and Clamped-Clamped boundary conditions are taken into the investigation with the help of the Differential Quadrature Method (DQM). Critical buckling load parameters are computed for the SS, CS, and CC boundary conditions from generalized eigenvalue problem. Graphical, as well as tabular results, are calculated by using MATLAB programmes and effects of various parameters such as fractional parameter, nonlocal parameter, aspect ratio on critical buckling load parameters extensively studied
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
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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