1,354,063 research outputs found
Boosted PWM open loop control of hydraulic proportional valves
No full textThis paper presents an innovative open loop control technique for direct single stage hydraulic proportional valves whose response rate is significantly higher than that obtained by standard open loop control techniques, even comparable to more costly commercial closed loop systems. Different from standard open loop techniques, which provide the coil with a constant current proportional to the target position, the control strategy proposed in this paper employs the peak and hold (P&H) technique, widely used in Diesel engine modern supply systems, to boost the duty cycle value of the pulse width modulation (PWM) signal for a short time, namely during the spool displacement, while maintaining a lower duty cycle for holding the spool in the required opening position. The developed "boosted PWM" technique only requires a low cost microcontroller, such as a peripheral interface controller (PIC) equipped with a metal oxide semiconductor (MOS) power driver. The PWM parameters are calibrated as a function of the spool displacement so as to maximize the response rate without introducing overshoots: the collected data are stored in the PIC. Different valve opening procedures with step response have been compared to demonstrate the merits of the proposed boosted PWM technique. No overshoots have been registered. Moreover, the proposed method is characterized by a significantly higher response rate with respect to a standard open loop control, which approximately has the same cost. Similar experimental tests show that the proposed boosted PWM technique has a response rate even higher than that provided by the more costly commercial closed loop system mounted on the valve, and it produces no overshoots
Un sistema di controllo automatico dei parametri di vinificazione per l’ottimizzazione del processo
No full textAutomated monitoring of the vinification process employing a set of sensors coupled with software in an innovative horizontal fermenter-drainer with submerged cap
No full text
Automated monitoring of the vinification process employing a set of sensors coupled with software in an innovative horizontal fermenter-drainer with submerged cap
No full textImpiantistica frigorifera innovativa con fluidi frigorigeni naturali
No full textNella seguente nota vengono esposte le linee programmatiche del progetto nazionale di ricerca sulle
“Tecnologie innovative sulla frigoconservazione con fluidi refrigeranti naturali”e l’attività finora
svolta dalle unità operative afferenti al progetto. Pertanto, dopo una sintetica introduzione sugli
effetti prodotti dall’emissione di fluidi refrigeranti sull’ambiente, sono stati riepilogati i regolamenti
emessi dagli accordi internazionali stipulati fra i vari Stati ed i limiti imposti dalla legislazione
europea sull’uso dei gas fluorurati.
Il progetto di ricerca ha previsto la costruzione ed il monitoraggio di tre impianti frigoriferi pilota
che utilizzano i due gas naturali di maggiore interesse e cioè l’anidride carbonica e l’aria.
Sono stati, quindi, esposti i criteri generali di progettazione degli impianti e la loro definizione
costruttiva, nonché le metodiche con cui si ritiene di valutarne l’efficienz
Un sistema di controllo automatico dei parametri di vinificazione per l'ottimizzazione del processo
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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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