1,720,999 research outputs found
Carta giacimentologica dei marmi delle Alpi Apuane a scala 1:10000 e sua informatizzazione – Sezione 249010 Carrara
No full textIdentification problem of groundwoter models. An approximate approach for transmissivity
No full textThe Authors suggest an approximate approch for the solution of the problem of the identification of transmissivity in porous ground: they suppose transmissivity is steady comparent to gradient bat not to divergence. We show a numeric example concerning the groundwater flow of the Low Esino Basin (Ancona - Italy
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
Optimal Decentralized Voltage Control for Distribution Systems With Inverter-Based Distributed Generators
No full textThe increasing penetration of distributed generation (DG) power plants into distribution networks (DNs) causes various issues concerning, e.g., stability, protection equipment, and voltage regulation. Thus, the necessity to develop proper control techniques to allow power delivery to customers in compliance with power quality and reliability standards (PQR) has become a relevant issue in recent years. This paper proposes an optimized distributed control approach based on DN sensitivity analysis and on decentralized reactive/active power regulation capable of maintaining voltage levels within regulatory limits and to offer ancillary services to the DN, such as voltage regulation. At the same time, it tries to minimize DN active power losses and the reactive power exchanged with the DN by the DG units. The validation of the proposed control technique has been conducted through a several number of simulations on a real MV Italian distribution system
Active management of renewable energy sources for maximizing power production
No full textThe continuous increasing penetration of Distributed Generation systems (DGs) into Distribution Networks (DNs) puts in evidence the necessity to develop innovative control strategies capable to maximize DGs active power production. This paper focuses the attention upon this problem, developing an innovative decentralized voltage control approach aimed to allow DGs active power production maximization and to avoid DGs disconnection due to voltage limit infringements as much as possible. In particular, the work presents a local reactive/active power management control strategy based on Neural Networks (NNs), able to regulate voltage profiles at buses where DGs are connected, taking into account their capability curve constraints. The Neural Network controller is based on the Levenberg–Marquardt algorithm incorporated in the back-propagation learning algorithm used to train the NN. Simulations run on a real Medium Voltage (MV) Italian radial DN have been carried out to validate the proposed approach. The results prove the advantages that the flexibility of the proposed control strategy can have on voltage control performances, generation hosting capacity of the network and energy losses reduction
3D geological modelling in support of underground mining industry
No full textThe present paper describes a working approach that involves the combination of Terrestrial Laser Scanning (TLS) and traditional geological surveys for creating the three-dimensional model of an underground quarry located on the Apuan Alps (Italy). The final model includes information on the geological structure and marketable marble varieties. TLS can be used to obtain detailed and accurate geometrical information in short working times by generating several point clouds that can accurately model the detected surfaces. The study area comprises a network of tunnels, for a total length of about 140 meters, and 20 different scan positions were necessary to cover the entire area. In order to register all the point clouds data to a unique reference system, a topographic survey was conducted. The coordinates of some optical targets, positioned at specific locations within the excavation area, were measured by employing a Total Station and two GPS receivers. Differential GPS surveys and post-processing procedures have guaranteed a sub-centimetric accuracy of the targets and, consequently, of the point clouds. From the 3D use of the data, the new topographic map of the quarry was generated at a scale of 1:500, and several 2D cross sections were created for better understanding of the quarry's actual scenario. The structural and morphological limits of the quarry surfaces were restituted directly from the point cloud data. Further, “non uniform rational basis-spline” surfaces (NURBS) were created by employing a specific modelling software, which allowed to create the 3D model of the quarry. The application of NURBS surfaces, instead of meshes has turned out to be a better option in terms of speed, accuracy, control of operations and for the requirement of powerful compute.
Detailed traditional geological were carried out and a new geological map including the marketable marble varieties was created. Five detailed geological cross sections were drawn by combining both surface and sub-surface data. Finally, the 3D geological model of the area was generated. The combination of the two models has helped in understanding the relationship between quarry and marble deposit and it allowed to make exact measurements of distances and to quantify the extractable marble volumes.
The present working approach can be adapted in different geological contexts, since it allowed to obtain a huge amount of data in short working times without sacrificing details and accuracy. Such properties make of it an important instrument to improve cultivation plans for both safety and commercial reasons
Dispersed Voltage Control in Microgrids
No full textThe deeper penetration of distributed energy resources (DERs) in microgrids ( s) has led to their wider deployment in specific applications. The inherent variability in loads and in renewable energy resource outputs necessitates the development and implementation of effective voltage control strategies so as to reliably serve the loads, particularly under islanded operations mode. We propose a dispersed control strategy to maintain voltage levels within the operational limits by means of the DERs reactive and active power outputs. We implement an optimization approach and demonstrate the effectiveness and the robustness of the proposed voltage control scheme using a set of representative studies from the extensive testing of the simulation approach performed with the methodology. Simulation results demonstrate the absence of any opportunity cost to implement the control action and the maximization of active power production by renewable energy resources
Superimposed exhumation-related deformation structures from cartographic to microscale: examples from the southeastern Alpi Apuane (Italy).
No full textVariations 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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