1,720,965 research outputs found
A comparison between resistance and induction DSS furnace for solar grade silicon production
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A new DSS furnace for energy saving in the production of multi-crystalline Silicon
No full textDue to the feedstock amount over the solar cells final cost, the production of low-cost and high quality Si in photovoltaic application is a main topic in PV industrial research. The large grained columnar poly crystalline Silicon obtained via Directional Solidification Systems (DSS) was found to be a convenient alternative to the expensive mono crystal obtained via Czochralski: production costs are much lower and the solar cells efficiency is significantly increased in comparison with the ones obtained via traditional growth. Among the main manufacturers of DSS systems the traditional resistance heating is used both in the phase of melting the raw Silicon and in the phase of re-crystallization in order to maintain the proper temperature gradient between the top and the bottom of the crucible. The induction heating technology could be a valid option, but only few manufacturers use it. In the paper a comparison between the two different technologies used in DSS for the production of columnar poly Si ingots will be presented and discussed: electric resistors and induction furnaces. The former is a well known and widely used technology. The latter is increasing in the last years. Pros and cons are considered for both systems: energy consumption during the whole process, heating up time, melting time, controlled cooling strategies, process regulation and global efficiencies are evaluated using electromagnetic and thermal simulations. The models used are based on real crucibles capacity in order to simulate processes and to compare the two different approaches. In collaboration with an Italian induction heating company a real iDSS prototype has been built and the process is going to be tested
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
METHOD AND DEVICE FOR OBTAINING A MULTICRYSTALLINE SEMICONDUCTOR MATERIAL, IN PARTICULAR SILICON
No full textMicrocomputer control of electric drives
No full textThe purpose of the paper is to investigate the application of a microcomputer system to the control of electric drives. The functions performed by such a system are firstly specified; operation of the microcomputer and of the input and output interfaces are the analysed, with special attention paid to the accuracy and timing demands. Speeding-up of the microcomputer throughput rate by means of look-up tables is also discussed
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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