1,720,993 research outputs found
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
Advanced Modelling of Thermal Plasmas for Industrial Applications
No full textAdvanced Modelling of Thermal Plasmas for Industrial Applications
V. Colombo, E. Ghedini
Department of Mechanical Engineering (D.I.E.M.) and Research Center for Applied Mathematics (C.I.R.A.M.)
Università di Bologna, Via Saragozza 8, 40123 Bologna, Italy
Modeling results are presented for different industrial thermal plasma sources using a customized version of the commercial code FLUENT capable of 2D and 3D transient simulation with advanced CFD models that take into account turbulence effects using different approaches (Reynolds Stress Model and Large Eddy Simulation), species transport and radiation (Discrete Ordinate Model with interaction between radiation and solid surfaces). Simulations results are presented in order to show the capabilities of this modeling tool, which is very useful for the design of a wide range of atmospheric pressure thermal plasmas devices and applications, such as: ICPTs with injection of powders for spheroidization purposes (showing the trajectory and heating history of powders injected in the torch through a carrier gas together with their effect on the plasma discharge for various geometric, electric and operating conditions by means of an improved turbulent version of a 3-D previously developed code where the helicoidal coil and the gas injection section of industrial plasma torches are taken into account without geometry simplifications), twin-torch DC transferred arc plasma systems for waste treatment (showing time-dependent effects arising in the fluid flow and temperature distribution of a plasma transferred electric arc discharge generated between two suspended metallic electrodes used inside a plasma furnace for hazardous waste incineration with turbulence effects taken into account using a RANS approach, as well as the effect on the discharge characteristics of using different types of plasma gas (air and Ar/H2 mixtures), for various geometric and operating conditions), DC non-transferred arc torch for plasma spraying (3-D time dependent model to simulate the behaviour of such a device without any external assumption on the anode restriking and attachment and to simulate also the downstream expansion of the plasma jet after the torch nozzle using a LES turbulence model).
D. Bernardi, V. Colombo, E. Ghedini, A. Mentrelli, Pure and Applied Chemistry, 77, pp. 359 – 372, (2005).
D. Bernardi, V. Colombo, E. Ghedini, A. Mentrelli, T.Trombetti, Czechoslovak Journal of Physics. 54, pp. C489 - C515 (2004).
D. Bernardi, V. Colombo, E. Ghedini, A. Mentrelli, T. Trombetti, IEEE Transactions on Plasma Science, 33, pp. 424–425 (2005).
D. Bernardi, V. Colombo, E. Ghedini, A. Mentrelli, IEEE Transactions on Plasma Science, 33, pp. 426–427 (2005).
D. Bernardi, V. Colombo, E. Ghedini, S. Melini, A. Mentrelli, Three-dimensional time-dependent modelling of magnetically deflected transferred arc, IEEE Transaction On Plasma Science 33, 428-429 (2005).
V. Colombo, E. Ghedini, Time Dependent 3-D Simulation of a DC Non-Transferred Arc Plasma Torch: Anode Attachment and Downstream Region Effects, Proc. of the 17th Int. Symp. on Plasma Chemistry-ISPC17 (2005).
V. Colombo, E. Ghedini, A. Mentrelli, E. Malfa, 3-D Modelling of DC Transferred arc Twin Torch for Asbestos Inertization. In Nuclear Reactor Physics. A collection of papers dedicated to Silvio Edoardo Corno, Torino, C.L.U.T., pp. 169 - 196 (2005).
V. Colombo, E. Ghedini, Time-Dependent 3-D Modelling Of Dc Transferred Arc Twin Torch, High Technology Plasma Processes 9 - HTPP9, St. Petersburg (2006)
Modelling and Comparison of Different Design Solutions for DC Transferred Arc Plasma Cutting Torches
No full textModelling and Comparison of Different Design Solutions for DC Transferred Arc
Plasma Cutting Torches
V. Colombo, E. Ghedini
Department of Mechanical Engineering (D.I.E.M.) and Research Center for Applied Mathematics (C.I.R.A.M.)
Università di Bologna, Via Saragozza 8, 40123 Bologna, Italy
S. Dallavalle, M. Vancini,
Cebora S.p.A., Via Andrea Costa 24, 40057 Cadriano di Granarolo, Italy
The aim of this work is to investigate by means of a 2-D and 3-D FLUENT© based numerical model the behaviour of different types of transferred arc dual gas plasma torches used for cutting of metallic materials, putting into evidence the physical reasons for the industrial success of various design and process solutions appeared over the last years, such as: secondary gas swirl injections with different directions, various different approaches for the geometry of the plasma chamber, the effect of externally superimposed magnetic fields. Flow and heat transfer equations are solved with coupled electromagnetic ones, for a LTE optically thin plasma, while turbulence phenomena are taken into account by means of a k-ε RNG model. Simulations include a prediction of the thermal behaviour of the solid components of the torch head, including electrode and hafnium insert, thermal histories and trajectories of hafnium oxide particles emitted from it under idealized conditions and the efficiency of nozzle and electrode cooling systems in various operating conditions including gas mixtures (O2/air, H35/N2, N2/N2). Radiation is included in the calculation of heat transfer to the surfaces of the components using a customized Discrete Ordinate (DO) model. Results obtained from the simulations of one of the plasma torches here considered are also compared with experimental measurements in order to perform a validation of the model for what concerns pressure values in different regions of the device, and the gas mass flow rate during the working phase. For this purpose two suitably modified plasma torches with pressure and temperature measurement systems have been designed and used during realistic cutting conditions.
V. Colombo, E. Ghedini, S. Dallavalle, M. Vancini, 3-D Fluidynamic and Plasma Characterization of DC Transferred Arc Plasma Torches for Metal Cutting. 17th International Symposium on Plasma Chemistry (ISPC-17). Toronto, august 2005.
V. Colombo, E. Ghedini, G. Masini, D. Russo, S. Dallavalle, M. Vancini, 2-D And 3-D Fluidynamic And Plasma Characterization Of Dc Transferred Arc Plasma Torches For Metal Cutting, High Technology Plasma Processes 9 -HTPP9, St. Petersburg (2006); in press on Journal of High Temperature Material Processes
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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