1,720,976 research outputs found
Accordi tra Comuni e servizi pubblici: una prima applicazione della sentenza n. 204/04 della Corte Costituzionale
No full textA 3D numerical model for turbidity currents
Full text linkA numerical model that solves two-phase flow motion equations to reproduce turbidity currents that occur in reservoirs, is proposed. Three formalizations of the two-phase flow motion equations are presented: the first one can be adopted for high concentration values; the second one is valid under the hypothesis of diluted concentrations; the third one is based on the assumption that the particles are in translational equilibrium with the fluid flow. The proposed numerical model solves the latter formalization of two-phase flow motion equations, in order to simulate turbidity currents. The motion equations are presented in an integral form in time-dependent curvilinear coordinates, with the vertical coordinate that varies in order to follow the free surface movements. The proposed numerical model is validated against experimental data and is applied to a practical engineering case study of a reservoir, in order to evaluate the possibility of the formation of turbidity currents
Converter control strategies for the power flow management in a fuel-cell supplied vehicle for the public city transportation
No full textDue to the high costs, the fuel cell technology is likely to be applied firstly in the public electrically-propelled vehicles. In a prospective framework, the intrinsic slow response of a fuel cell stack to the load variation could be compensated by
conventional electrochemical batteries, which are in turn protected versus the short-time power pulses by super-capacitors. This paper presents a strategy for the power
allocation among the different sources, applied to a likely system configuration, and its implementation in a Matlab®–Simulink® model, taking into account the behaviour of all the electromechanical components. The simulations are executed both for a normalized drive cycle and for a more realistic urban running, in order to verify their effectiveness also in a randomly perturbed route
Numerical Simulation of the Shoreline Modifications behind a T-Head Groin
Full text linkIn this paper, the shoreline and bottom modifications produced by the presence of a T-head groin are simulated. We present a model for the bottom-change simulation, composed by two sub-models: a two-dimensional phase-resolving model for the simulation of the variation of the fluid dynamic variables inside the wave period and that takes into account the undertow; a second morphodynamic sub-model for the simulation of the bottom changes, in which the suspended sediment concentration is calculated by means of the wave-averaged advection-diffusion equation. Both the fluid motion equation and the concentration equation are written in a new contravariant formulation. We simulate the velocity fields from deep water to the start of the surf-zone by a new integral contravariant form of the Fully Nonlinear Boussinesq Equations. We simulate the bed evolution dynamics by means of the contravariant formulation of the advection-diffusion equation for the suspended sediment concentration. A quasi three-dimensional approach is used to formulate the advective sediment transport terms in the advection-diffusion equation
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
uno schema upwind weno ed un solutore del problema di riemann per la forma controvariante delle equazioni delle acque basse
No full textNel presente lavoro viene proposto uno schema numerico di tipo Upwind Weighted
Essentially Non-Oscillatory per la risoluzione delle equazioni delle acque basse in
sistemi di coordinate curvilinei generalizzati. Le equazioni delle acque basse sono
espresse in una formulazione controvariante in cui non compaiono i simboli di Christoffel.
Le equazioni sono risolte per mezzo di uno schema ad alta risoluzione ai
volumi finiti in cui si utilizza un solutore di Riemann esatto
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
