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Evaluation of the Efficiency of a Vibrating Propulsion System for Marine Vessels, Part II: Integration of Motion Equations and Performances
No full textIn this paper we present the results obtained by numerical simulation regarding the propulsion device for boats equipped with the system of counter rotating masses discussed in Part I. The equations of motion of the systems illustrated in Part I are integrated and the performances of the propulsion are evaluated by considering a model with two pairs of counter rotating masses driven by unilobe elliptical gears. In order to evaluate the propulsive efficiency of the device, by applying the formulas previously outlined and based on the direct use of the energy equation, the powers provided and consumed by the system for obtaining a rectilinear motion are computed. The simulations have been performed with reference to a vessel CAD model whose length is approximately equal to 13 m (the previous studies, as discussed by Muscia and Sciuto 2009, 2010, Muscia 2015, considered a vessel model 1.7 m long). The stern of this vessel has a particular shape. The propulsive efficiency has been calculated with reference to a situation of steady motion. Correlations between numerical experiments on models and possible full scale application are discussed
Evaluation of the Efficiency of a Vibrating Propulsion System for Marine Vessels, Part I: Physical Mathematical Models
No full textIn this paper some analytical developments concerning the possibility of generating a rectilinear motion of vessels subject to vibration, without the use of propellers are presented. The motion is obtained by a device equipped with counter rotating masses installed in the boat which vibrates along the longitudinal direction. The hull has a suitably shaped stern. The study considers an analysis for evaluating the energy that the propulsion system consumes in relation to its performances. A further aim was to increase the speed of the system. This result is obtained by using elliptical gears to transmit the motion from the driving motor to a two or more pairs of counter rotating masses. This solution allows one to reach the variability of the angular velocity of the counter rotating masses during each revolution in accordance with certain laws that maximize the thrust applied to the vessel preferentially along a direction with respect to the opposite one, all things being equal. A formulation to compute the propulsive efficiency of the device study is developed. Some remarks in relation to practical applications and critical issues of the proposed approach are shortly discussed. In the second part of the paper the results relative to a vessel 13 m long are illustrated
Hydrogen-implantation ed effetti di anelasticità in metalli di transizione
No full textQuesta memoria contiene la tesi di laurea in Fisica di Alberto Francescutto (Relatore prof. L. Verdini, Corr: prof. P. Ciuti) pubblicata come Rapporto Tecnico dell’Istituto Nazionale di Acustica “O. M. Corbino”
THE NEW HYBRID SMALL PASSENGER VESSEL FOR THE VENICE LAGOON
No full textA greater awareness on the reduction of pollution from transport vehicles is increasingly manifest, and also
the marine transport has been recently involved by specific normative on the matter. In particular, the
European Community has put into force various antipollution directives for the inland waterway transport,
which shall set up a deep evolution in the next few years. A possible solution may be represented by the
adoption of hybrid-electric propulsion systems on board. In such a direction many applications have been
made for large merchant and naval ships, but for small vessels very few experiences have been till now
carried out.
This paper presents the results of the conversion of the propulsion system of a typical small passenger
vessel operating in the Venice Lagoon from a conventional system based on Diesel engine to a hybridelectric
one. The vessel has been built, and can be considered an useful and precious existing test bench
to validate such technologies in terms of eco-friendliness, energy efficiency and reliability
INNOVATIVE TOOLS FOR THE ADVANCED EVACUATION ANALYSIS OF PASSENGER SHIPS
No full textThe current trend for the new cruise ships is toward giant constructions having a degree of more and more
enhanced complexity, along with an increased number of passengers and crew members.
The Regulations in force concerning safety matters ("Safe Return to Port") are mainly addressed in
increasing the intrinsic survival capability of the ship in event of fire or flooding below a predefined
threshold. When the casualty threshold is exceeded an orderly evacuation and abandonment of the ship
shall be guaranteed. Lessons learnt by the grounding of the "Costa Concordia" have shown that only a
proper planning of the evacuation is the basic premise to ensure a safe abandonment of the ship.
Nowadays, the evacuation analysis is imposed only for ro-ro passenger ships. Meanwhile, the IMO has
decided some amendments to both SOLAS and FSS Code in order to make mandatory the evacuation
analysis also for new passenger ships, starting from February 2016. Innovative tools for the advanced
evacuation analysis, which take into account the different human factors affecting the movement of a
crowd in great agitation, are presented. A thorough analysis for a passenger ship is carried out, and the
performance standard, which expresses the capability of the ship in terms of time necessary for its
evacuation and abandonment, is checked
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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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