1,720,977 research outputs found
New approximate boundary conditions for the Large Eddy Simulation of turbulent wall flows
No full textNew wall condition and noncommutation error formulation in the large-eddy simulation of the channel flow, communication to the the 10th European Turbulence Conference, Trondheim, 29 June - 2 July 2004 http://www.tandfonline.com/doi/abs/10.1080/14685240500322701
No full textthe 10th European Turbulence Conferenc
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
Carichi effluenti dagli scaricatori di piena di fognature unitarie. Inquadramento teorico e valutazioni numeriche di lungo periodo.
No full textLa nota descrive un inquadramento teorico ed un'analisi numerica volti alla determinazione delle masse di inquinante sversate nei recapiti superficiali da scaricatori di piena (con e senza annesse vasche di pioggia) inseriti in reti di drenaggio di tipo unitario. L'inquadramento teorico, fondato su alcune ipotesi semplificative che studi sperimentali recenti hanno pero' mostrato essere accettabili se la base temporale di riferimento e' sufficientemente estesa, ha consentito di giungere ad una soluzione generale del problema, per un prefissato regime pluviometrico. Oltre al volume idrico complessivamente sversato verso il recapito, risulta fondamentale la conoscenza di un raggruppamento adimensionale, rappresentativo del rapporto di mescolamento medio efficace tra le acque reflue e quelle meteoriche. L'andamento di tali grandezze e' stato poi determinato, per via numerica e su base temporale annua, per il regime pluviometrico milanese. Si sono analizzati sia scaricatori "semplici" cioe' privi di invasi, che scaricatori abbinati a capacita' di invaso di tipo ON-LINE ed OFF-LINE.
Gli abachi cosi' ottenuti possono essere utilizzati per stimare l'apporto di inquinanti persistenti in corpi idrici a debole ricambio e per valutare l'efficacia dei volumi di invaso nella riduzione dell'impatto
Absence of Inelastic Collapse for a 1D Gas of Grains with an Internal Degree of Freedom
No full textAbstractIn a cooling gas of rigid particles interacting with a constant coefficient of restitution, groups of particles within the gas may experience an infinite number of collisions in a finite time. This singularity, named inelastic collapse, is a shortcoming of the mathematical model, and it hampers the efforts of simulating a freely evolving, cooling granular system. After a brief review of previous works addressing the problem, we propose a one-dimensional model where a grain is seen as a pair of point masses joined by a massless, dissipative spring. We show that binary interactions of such grains are described as impacts with a constant restitution coefficient, whose expression is given in terms of the spring parameters. However, the impact is not instantaneous, but it requires a finite time. We show that in situations that would lead to inelastic collapse, multiple interactions among grains transfer kinetic energy into potential energy associated with the deformation of the springs, rather than dissipate it. This effectively avoids the collapse. Finally, we discuss the results of the simulations of a cooling granular system in comparison with other models
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
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