1,721,036 research outputs found
Boiling Regimes in a Closed Two-Phase Thermosyphon
No full textExperimental results and an analytical model on the boiling mechanisms in a closed two-phase thermosyphon are presented in order to define the frontiers between the main boiling regimes and, in particular, the frontier between intermittent boiling and fully-developed boiling. The boiling regimes are classified on the basis of the frequency of bubble nucleation and the ratio of bubble diameter to device diameter. A criterion for the intermittent/developed-boiling frontier is based on the ratio of the bubble-nucleation waiting time and the bubble growth time. From this criterion a correlation between power throughput, working-fluid pressure and nucleation critical superheat are obtained. Experimental data on operating conditions, temperatures, and nucleation frequencies show the same functional dependence as the proposed correlation
Evaluation of the liquid charge for a closed two-phase thermosyphon
No full textWe present experimental results and a simplified theoretical model on the volume filled by the liquid-vapor mixture in the evaporator of a closed two-phase thermosyphon as a function of the power throughput. The volume filled by the mixture depends on its average density. Thus, we first correlate the mixture density to the vapor mass flow rate; then, we evaluate the density average value over the mixture volume. Finally, we derive an analytical correlation between the mixture volume, the liquid charge and the power throughput. Experimental results on the mixture volume agree well with the values calculated with the proposed correlation
Robert de Niro a la derecha y Jairo Madrid a la izquierda
No full textRobert de Niro a la derecha y Jairo Madrid a la izquierda
Filmación de la pelicula "La Misión", Robert de Niro a la derecha con barba
No full textFilmación de la película "La Misión", Robert de Niro a la derecha con barba
Variable-conductance wall based on the Knudsen conduction regime
No full textWe describe the operation of a vessel with variable-conductance walls, based on the superposition of heat transfer by radiation and conduction through a rarefied saturated-vapor, in transition between the Knudsen and the continuum behavior. The rarefied vapor fills a narrow gap between two thin walls. We derive an analytical correlation to estimate the heat flux between the two thin walls and through the narrow gap filled by rarefied saturated-vapor. We discuss the heat transfer characteristics of such a container for some cases of technological interest. We present a set of design criteria
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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