1,721,094 research outputs found
Relazione attività relativa all'azione CAST3M
Full text linkNel presente rapporto sono state evidenziate le attività svolte nel periodo di consuntivazione maggio 2009 - settembre 2010 delle attività svolte nell'ambito dell'azione CAST3M. In particolare sono riportati: - il materiale oggetto dei corsi di formazione nella termo-meccanica delle strutture orientata all'impiego di CAST3M; - le modifiche apportate alla procedura HTCTRAN per riattivarne il funzionamento; - Lo stato dell'arte sulla struttura dei calcestruzzi con particolare riferimento agli aspetti connessi con il trasferimento del calore
Caratterizzazione meccanica dei materiali costituenti il nucleo e i contronuclei di una diga in terra: la diga di Bilancino
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S-shaped waveguide-induced asymmetry between counter-propagating modes in a racetrack resonator
Full text linkOngoing progress in photonic integrated circuits necessitates the integration of semiconductor ring lasers (SRLs) with high performance and predictable behavior, which can be achieved when the symmetry of the SRL, which supports both clockwise and counterclockwise beam propagation, is unbalanced through loss mechanisms inside the resonator. In this work, numerical simulations were carried out on the symmetric layout of the racetrack resonator equipped with an asymmetric S-shaped internal waveguide. The simulations results were compared with the ones of analogue structures without internal waveguide showing the benefit induced by this additional element in term of the unidirectionality of the SRL
Lo chiamavano il Paese del sole: il fotovoltaico italiano tra spontaneo insediamento e pianificazione
No full textGeometry optimization of unidirectional integrated ring laser
Full text linkRing lasers, evanescently coupled to an adjacent optical waveguide, are essential components for the upcoming generation of integrated sources. In an ideally symmetric resonator, emission occurs from the both clockwise and counter-clockwise directions, resulting in a potential waste of emitted optical power, while unidirectional emission has been reported in different configurations, for example when asymmetric external reflectivities are used for the coupling waveguide. In the integrated form, a common approach consists in the inserting an S-bend waveguide in the ring, in such a way that the field propagating in the direction that we want to suppress is reinjected in the other direction. The S-bend waveguide must be carefully designed to reduce optical losses and to ensure a sufficient suppression of the undesired field. Using 2D finite- difference time-domain simulations performed with Synopsys RSof
Comparison of LSTM-Based Prediction Strategies for Grid Modal Parameters Forecast
No full textThe high penetration of renewable energy sources poses great challenges for transmission system operators, especially concerning the detrimental phenomenon of electromechanical Inter-Area Oscillations. Although the actual monitoring techniques can offer a useful baseline in order to fight against such phenomena, predictive features are highly desirable in this context. This work presents a preliminary comparative study of two prediction strategies suitable to forecast the short-term values of the grid modal parameters. The considered strategies are based on the proper integration of the Dynamic Mode Decomposition technique with Machine Learning techniques such as Long-Short-Term Memory units and Ensemble methods. The development steps of both techniques are fully illustrated and the performance comparison is done by accounting for some key performance indicators. Two assessment scenarios are considered, based on the availability of some real measurement data
Power System Resilience Improvement Provided by VSC-HVDC Link Flexibility
No full textVSC-HVDC links can play a significant role in improving power system resilience due to their inner ability in properly regulating active and reactive powers in effective way. Because of that the dynamic behavior of the whole system can be improved in a remarkably way also by implementing innovative functions not foreseen in the classic power systems. These are necessary due to the growing tendency in using of production systems from renewable sources, as for example the emulation of inertia for counteracting the dramatic reduction of total system inertia. In this paper, a control strategy is tailored that can guarantee the participation of the HVDC link to the frequency regulation and voltage regulation at the point of connection buses, while ensuring the desirable level of synthetic inertia thanks to the DC capacitance installed at the connection buses. The control strategy is derived without loss of generality with respect to a two-area system with AC-DC link but can be easily extended to more complex systems. The control laws of the different loops, which are decoupled over the time, are designed by the well-known open loop shaping technique. The results of the numerical applications allow confirming the validity of the assumptions performed in the procedure of choosing of the various controller parameters
Numerical Simulation and Experimental Results of Filament Wound CFRP Tubes Tested under Biaxial Load
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Topology-based Clustering Techniques for Graph Partitioning Applied to the Italian Transmission Network
Full text linkAs renewable energy sources are integrated into power systems, the complexity of their management increases. For the analysis of modern power systems, clustering algorithms have become indispensable tools. The representation of an electric power transmission system involves conceptualizing it as a graph-a mathematical structure depicting a set of nodes and edges. In the context of power systems, these nodes correspond to buses, and the edges represent branches. Weighting may be assigned to the edges to denote the strength of their connections. In this paper, spectral clustering and hierarchical agglomerative clustering have been employed to analyze the Italian transmission network. Spectral clustering relies on the eigenvalues and eigenvectors derived from the Laplacian matrix associated with the network. The hierarchical agglomerative clustering, based on Th & eacute;venin impedance to define the distances, merges the two closest clusters at each step. The primary objective of this research is to identify distinct areas within the network based solely on its topology. In pursuit of this goal, admittances and Th & eacute;venin impedances have been employed as weights in the graph representation. By utilizing these approaches, the research aims at uncovering meaningful structures and patterns within the power transmission system based on the inherent connectivity and strength of the network elements. The techniques have been used on two real network models to demonstrate the performance of the algorithms with different grid configurations
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