1,721,020 research outputs found
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
Analysis of Flow Instabilities on a Three-Bladed Axial Inducer in Fixed and Rotating Frames
No full textThe paper describes the results of recent experiments carried out in the Cavitating Pump Rotordynamic Test Facility for the dynamic characterization of cavitation-induced flow instabilities as simultaneously observed in the stationary and rotating frames of a high-head, three-bladed axial inducer with tapered hub and variable pitch. The flow instabilities occurring in the eye and inside the blading of the inducer have been detected, identified, and monitored by means of the spectral analysis of the pressure measurements simultaneously performed in the stationary and rotating frames by multiple transducers mounted on the casing near the inducer eye and on the inducer hub along the blade channels. An interaction between the unstable flows in the pump inlet and in the blade channels during cavitating regime has been detected. The interaction is between a low frequency axial phenomenon, which cyclically fills and empties each blade channel with cavitation, and a rotating phenomenon detected in the inducer eye
PulCheR – Pulsed Chemical Rocket with Green High Performance Propellants: First Year Project Overview
Full text linkPulCheR (Pulsed Chemical Rocket with Green High Performance Propellants) is a research project co-funded by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n°313271. The project officially started as of January 1st, 2013, and is mainly aimed at demonstrating the feasibility of a pulsed propulsion system in which the propellants are fed in the combustion chamber at low pressure and the thrust is generated by means of high frequency pulses, reproducing the defence mechanism of a notable insect: the bombardier beetle. The feasibility of this new propulsion concept will be investigated at breadboard level in both mono and bipropellant configurations through the design, realization and testing of a platform of the overall propulsion system including all its main components. As an added value, the new propulsion concept will be investigated using green propellants. The present paper aims at introducing the project, its structure, its main objectives and at presenting an overview of the activities performed in the first year of the project and its current status
Dynamics of the Blade Channel of an Inducer Under Cavitation-Induced Instabilities
No full textA high-head three-bladed inducer has been equipped with pressure taps on the hub along the blade channels with the aim of more closely investigating the dynamics of cavitation-induced instabilities developing in the impeller flow. Spectral analysis of the pressure signals obtained from two sets of transducers mounted both in the stationary and rotating frames has allowed to characterize the nature, intensity, and interactions of the main flow instabilities detected in the experiments: subsynchronous rotating cavitation (RC), cavitation surge (CS), and a high-order axial surge oscillation. A dynamic model of the unsteady flow in the blade channels has been developed based on experimental data and on suitable descriptions of the mean flow and the oscillations of the cavitating volume. The model has been used for estimating at the inducer operating conditions of interest the intensity of the flow oscillations associated with the occurrence of the CS mode generated by RC in the inducer inlet
Pumping and Suction Performance of a Whirling Inducer
Full text linkThe experimental characterization of the rotordynamic fluid forces acting on a whirling inducer and the analysis of their influence on its pumping and suction performance are presented and discussed as functions of the operational conditions. The paper illustrates the first application of the novel approach recently developed at Alta for the simultaneous measurement of the relevant experimental data, demonstrating its remarkable versatility and effectiveness
Influences of the operating conditions on the rotordynamic forces acting on a three-bladed inducer under forced whirl motion
No full textIn the present paper the results from an extensive experimental characterization of the rotordynamic forces acting on a whirling three-bladed, tapered-hub, variable-pitch inducer are presented. The campaign has been conducted in the CPRTF (Cavitating Pump Rotordynamic Test Facility) at ALTA S.p.A.. The forces acting on the impeller have been measured by means of a rotating dynamometer mounted just behind the inducer. The roles of the rotor whirl motion, flowrate, cavitating condition and liquid temperature have been investigated. The analysis has been conducted by means of the classical rotordynamic approach together with a recent experimental technique, consisting in measuring the rotordynamic forces continuous behavior (spectra) as functions of the whirl excitation frequency. This technique allows for evaluating information from experiments more rapidly and accurately with regards to previous methods. Therefore, it is useful to better capture the complexity of the rotordynamic forces and assess their consequences on the stability of axial inducers
Linee Guida per il Giudizio di Plausibilità e Congruità delle Spese per Trattamenti Fisioterapici in Caso di Traumi Minori
No full textIl documento è risultato della collaborazione tra l’Associazione Medico-Giuridica M. GIOIA e la SIMFER (Società Italiana di Medicina Fisica e Riabilitazione), che hanno costituito un Gruppo di Studio congiunto per l’elaborazione di un protocollo comune sulla valutazione della congruità delle spese mediche per i trattamenti fisioterapici e riabilitativi
Experimental Characterization of Rotordynamic Forces Acting on Space Turbopumps
Full text linkThe experimental characterization of the rotordynamic fluid forces acting on a whirling inducer and the analysis of their influence on its pumping and suction performance are presented and discussed as functions of the operational conditions. The paper illustrates the first application of the novel approach recently developed at Alta for the simultaneous measurement of the relevant experimental data, demonstrating its remarkable versatility and effectiveness
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