1,721,541 research outputs found
A critical evaluation of micromechanical models for syntactic foams
No full textThe purpose of this work is the accurate prediction of the effective elastic moduli of syntactic foams, for arbitrary selection of the volume fraction and material for the matrix and the filler (made up of hollow spheres called balloons). Hence, we develop a series of three-dimensional finite element models, each including 50 balloons, for a wide range of geometric and material properties. This allows us to garner accurate reference data to ascertain the quality of the predictions of theoretical models available in the literature. In particular, we compare the Composite Sphere-based Self-Consistent estimate originally proposed by Hervé and Pellegrini [Hervé, E., Pellegrini, O., 1995. The elastic constants of a material containing spherical coated holes. Arch. Mech. 47, 223–246] and further developed by Bardella and Genna [Bardella, L., Genna, F., 2001. On the elastic behaviour of syntactic foams. Int. J. Solids Struct. 38, 7235–7260] with the Hollow Inclusion-based Differential Self-Consistent estimate recently proposed by Porfiri and Gupta [Porfiri, M., Gupta, N., 2009. Effect of volume fraction and wall thickness on the elastic properties of hollow particle filled composites. Compos. Part B – Eng. 40, 166–173]. We also discuss the results on the basis of (i) a novel Composite Sphere-based Differential Self-Consistent estimate, (ii) both rigorous and Composite Sphere-based bounds, and (iii) a re-derivation of the Hollow Inclusion-based Differential Self-Consistent estimate coherent with classical and Morphologically Representative Pattern-based homogenisation procedures considered in this work
sj-pdf-1-lup-10.1177_0961203320918011 - Supplemental material for Nuclear magnetic resonance–based targeted profiling of urinary acetate and citrate following cyclophosphamide therapy in patients with lupus nephritis
No full textSupplemental material, sj-pdf-1-lup-10.1177_0961203320918011 for Nuclear magnetic resonance–based targeted profiling of urinary acetate and citrate following cyclophosphamide therapy in patients with lupus nephritis by Sujata Ganguly, Umesh Kumar, Nikhil Gupta, Anupam Guleria, Sanjukta Majumdar, Sanat Phatak, Smriti Chaurasia, Sandeep Kumar, Amita Aggarwal, Dinesh Kumar and Ramnath Misra in Lupus</p
Failure of glass-microballoons/thermoset-matrix syntactic foams subject to hydrostatic loading
No full textThis study focuses on a lightweight syntactic foam constituted by an epoxy matrix filled with polydispersed Glass Microballoons (GMs) up to 0.75 volume fraction. We present experimental results on hydrostatic loading which demonstrate the possibility of different failure modes depending on whether the surface of the composite is painted/coated or not. In order to explain this surprising behaviour, we propose a three-dimensional Finite Element (FE) micromechanical model. First, we develop a cubic MultiParticle Unit Cell (MPUC) which includes 100 randomly placed GMs and accounting for their polydispersion, in terms of both size and radius ratio. This model is validated by subjecting it to effective uniaxial stress and comparing its predictions of the elastic moduli with experimental findings and an analytical homogenisation technique. Second, towards modelling failure, we implement a structural criterion proposed by our group, which posits that any GM undergoes brittle failure when its average elastic energy density reaches a critical value. We then utilise our measurements of the effective strength under uniaxial compressive stress to identify different critical values for selected types of GMs. Third, on the basis of the MPUC, we reach our goal by developing a larger FE model, including 300 GMs, which enables the study of the stress diffusion from the external surface through an appropriately thick layer of composite, under macroscopic uniform pressure.
This micromechanical model allows us to demonstrate the influence of the paint/coating on the syntactic foam failure mode
through a detailed analysis of the collapsed GMs and the matrix stress state
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
Founder's Day and Fifteenth Convocation and R R Kale Memorial Lecture (Photographs)
No full textFifteenth Convocation of the Institute held on February 6, 2009. Thirty Four successful students from the batch 2006-2008 were awarded their M.A. (Economics) degree. Professor Prabhat Patnaik, Centre for Economic Studies & Planning, Jawaharlal Nehru University, New Delhi, was the Chief Guest of the function. He also delivered the Kale Memorial Lecture, 2008 on “Speculation and Growth in Contemporary Capitalism”. Mr. Nikhil Gupta, who secured first rank with an 'A+' grade in the M.A. Examination, held in May 2008, was awarded the Pandurangi Prize and Late Professor M.V. Namjoshi Prize for securing highest marks in the course B04: Industry: Organization, Structure and Problems. (i) Ms. Charu Gupta, (ii) Ms. Geetha Gokul and (iii) Mr. Nikhil Gupta (jointly) awarded R.M. Agnihotri Prize for securing the highest marks in the course A09: Economics of Development
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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