1,721,045 research outputs found
La distribuzione dell’aria con terminali individuali
No full textL’intervento tradizionalmente adottato per migliorare la qualità dell’aria negli ambienti è quello di “ventilarli” con aria esterna, operazione che può sembrare semplice ed efficace, ma che ha forti ricadute sul comfort termico e sui consumi energetici. Per coniugare queste esigenze spesso contrastanti, sono state proposte nuove soluzioni impiantistiche tra le quali molto promettenti sono i sistemi di ventilazione localizzati, che concentrano l’azione dell’impianto là dove essa è effettivamente richiesta (cioè, di norma, in prossimità degli occupanti). Tuttavia, proprio il fatto che si creino volutamente condizioni non uniformi nell’ambiente rende la progettazione di questi impianti piuttosto delicata, sia perché non si possono applicare gli usuali metodi di dimensionamento, sia perché aumentano i rischi di discomfort localizzato. Pertanto, in questo lavoro verranno analizzati gli strumenti oggi disponibili per una più precisa e consapevole progettazione di questi impianti, esaminando poi a titolo di esempio alcuni casi applicativi di particolare interesse
Caratterizzazione Energetica dell’ Involucro Edilizio e Gradi-Giorno Modificati
No full textIl lavoro illustar una procedura di calcolo per la caratterizzazione energetica degli edific
R513A condensation heat transfer inside tubes: Microfin tube vs. smooth tube
No full textThe imminent phase-down of the common refrigerant R134a is calling for lower GWP alternatives. Real alternatives must have a lower global warming impact and they should be not flammable. In this context, R513A (azeotropic mixture made of R1234yf and R134a at 56% and 44% by mass) has been proposed as alternative to R134a due to its similar thermodynamic and transport properties and due to its lower GWP. This paper proposes a direct comparison between the thermal performances of a 3.5 mm ID smooth tube and those of a 3.4 mm ID microfin tube, during R513A condensation under the same working conditions of vapor quality (from 0.10 to 0.99), of mass velocity (from 100 to 1000 kg m−2 s−1), and of saturation temperature (30 °C and 40 °C). The comparison permits to highlight in which working conditions the microfin tube leads to a real heat transfer augmentation which is higher than the mere increase of heat transfer area. In the end, the experimental heat transfer coefficients, both for the smooth tube and for the microfin tube, are compared against values calculated with empirical correlations from the open literature
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
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