1,721,029 research outputs found
A procedure to evaluate the seven parameters of the two-diode model for photovoltaic modules
No full textThe paper presents an analytical procedure to calculate the seven parameters of the two-diode model of photovoltaic (PV) panels for any value of the solar irradiance and cell temperature. Six parameters (the photocurrent, the diode reverse saturation currents, the quality factor of the first diode and the series and shunt resistances), are evaluated by solving the equations related to the properties of the main points of the current-voltage (I-V) characteristics. The further information, necessary to calculate the entire set of seven truly independent parameters, is based on two conditions that have to be simultaneously satisfied: 1) the exclusion of negative values of the model parameters; 2) the minimization of the difference between the diode quality factors, which permits to obtain more precise I-V curves of the PV modules. A method to extend the application of the two-diode model to conditions that are different from the standard rating conditions (SRC) is presented. The comparison with alternative two-diode models showed that accurate representations of the I-V characteristics can be achieved using the proposed procedure regardless of the typology of the PV devices (monocrystalline, polycrystalline, HIT, amorphous silicon, CIS, CIGS, tandem)
Il metodo delle funzioni di trasferimento applicato ad un singola zona termica
No full textNel lavoro viene presentato un algoritmo basato sull’utilizzo dell’operatore Z-Trasformata per lo studio della trasmissione del calore all’interno di una singola zona termica costituita da pareti multistrato. L’algoritmo utilizzato è molto versatile e potrebbe venire utilizzato per il calcolo dei coefficienti delle funzioni di trasferimento nella simulazione del comportamento termico di un ambiente in free floating. Noti i coefficienti delle funzioni di trasferimento è possibile simulare in regime dinamico il profilo della temperatura di ciascuna superficie interna e dell’aria interna all’ambiente analizzato. L’algoritmo viene descritto in maniera completa in tutte le sue parti. Per valutare l’affidabilità dell’algoritmo è stato realizzato un confronto fra dati di simulazione ottenuti con esso e quelli ottenuti con il programma di simulazione termica denominato TRNSY
Uno strumento di supporto alla decisione nel campo dei software per la simulazione termica degli edifici in regime vario
No full text
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
ENVIRONMENTAL AND ENERGY PERFORMANCES OF BUILDING PRODUCTS: A WORKING CHAIN BASED ANALYSIS
Full text linkThe present work is aimed at investigating the environmental and energy performances of products to be utilized in buildings. Specifically, marble (Section 1), granite (Section 2) and natural materials (Section 3) will be analyzed.
The marble features are here studied on the basis of a field working chain audit. Particularly, two representative firms of the Custonaci productive basin (Trapani) have been considered. Their working chain have been investigated, by the point of view of the energy and materials flows, with a classical Life Cycle Assessment (LCA) approach. Moreover, the social and economic impacts of such materials have also been assessed by means of the Life Cycle Costing (LCC) and Social Life Cycle Assessment (S-LCA) approaches. By the way, the here presented S-LCA study represents one of the few presently available in the literature.
The granite has been analyzed by an energy and materials point of view, in the aim of singling out the possibility of reducing the amount of energy involved in the productive process along with the potentiality for reusing the waste materials resulting from the present working chain. The study refers to Spanish firms, due to the period that the author spent in this country, thanks to a PhD fellowship granted by the University of Palermo.
The possibility of utilizing natural materials, like hay and hemp, has been finally investigated by means of an experimental approach. The studies was conducted in the laboratory for indoor and building materials currently operating within the Department DEIM of the University of Palermo
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