1,720,982 research outputs found
THE INFLUENCE OF SEPARATION, INCLINATION AND SWIRL ON SINGLE AND COUPLED JET FANS INSTALLATION EFFICIENCY
No full textExperimental tests have been carried out in order to acquire knowledge about the interaction between jet fans and the resulting secondary flow in tunnels with standard circular A.N.A.S. (Italian Road Board) cross section. During the experiment programme, model jet fans are hug with different distances between jet axes, tunnel roof and pitch angles. The resulting tunnel flow, with develops along the tunnel, is studied using a five hole probe and the effectiveness of the impulse fan is determined. In the test series the velocity distribution at the nozzle exit has been changed and the difference of the swirl has been evaluated. The aerodynamic characteristics of the single and couple jet fans as well as the probable onset of recirculation are reported as a function of the effects of eccentricity and pitch angle
Experimental investigation of interaction of jet fans mounted in series
No full textA road tunnel ventilation system should be objectively grated taking into account both the installation efficiency of individual fans and the interaction between adjacent fans and consecutive fan sets. This can be a reason for reduced of installation efficiency penalties and excessively high installation prices.
A comprehensive series of tests were carried out on a 1/10 scale model of a vehicle tunnel in order to investigate the effects of tunnel velocity, jet swirl, jet momentum, inclination and distances between jet axes and tunnel roof. To determine the effect on installation efficiency and on the interactions between fans mounted in series.
Recommendations have been derived for the design and operation on the longitudinal ventilation system
Experimental Study on the Longitudinal Ventilation System
No full textIn longitudinal ventilation road tunnel systems the booster fans are mounted close to the tunnel roof. Since velocities of the flow are high, the friction losses on the walls are an important elements in these types of application.
Tests have been carried out to determine the effectiveness of the impulsive fan. The actual impulse force delivered has been measured on a tunnel model with standard ANAS (Italian Road Board) cross section.
During the research the distance of the jet axis from the wall and the tunnel velocity have been varied.
In the final test series the velocity distribution at the nozzle exit has been changed and the influence of the jet swirl has been evaluated
Uno Studio Sperimentale sulla Ventilazione Longitudinale nelle Gallerie
No full textCome influiscono sull'induzione le componenti assiale e trasversale della velocità del getto e la posizione del ventilatore rispetto alla sagoma della galleri
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
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