Gianluca De Marzi
ENEA
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Featured researches published by Gianluca De Marzi.
IEEE Transactions on Applied Superconductivity | 2015
Marco Breschi; Marco Casali; Lorenzo Cavallucci; Gianluca De Marzi; Giordano Tomassetti
A YBCO cable-in-conduit conductor (CICC) for high field magnet applications as well as for energy transmission is under development at the ENEA Frascati Superconductivity Laboratory. The cable is designed to carry up to 20 kA at 5 K and 12 T and is composed of five stacks of 30 YBCO tapes each, arranged in a twisted stacked configuration inside an aluminum stabilizer and an external jacket. The cooling is provided by forced convection of supercritical helium that flows in a central channel and in cavities manufactured between the superconducting stacks and the aluminum core. A first dummy prototype of the cable has been produced by TRATOS Cavi S.p.A., Italy, in order to assess the feasibility of the manufacturing process. This paper presents a 3-D coupled electric and thermal model of the cable, developed at the University of Bologna in a COMSOL Multiphysics environment. The model adopts a homogenization procedure to describe the tape stacks in a finite-element method approach with considerable saving on the number of degrees of freedom. The model is applied to the computation of the cable current sharing temperature and to the investigation of quench due to a distributed disturbance.
IEEE Transactions on Applied Superconductivity | 2015
Gianluca De Marzi; G. Celentano; A. Augieri; L. Muzzi; Giordano Tomassetti; Antonio della Corte
In 2013, the Superconductivity Laboratory at ENEA (the Italian National Agency for New Technologies, Energy, and Economica Developments) started a project aimed at using second generation (2G) High-Temperature Superconductors (HTS) tapes for the manufacture of a cable-in-conduit conductor. The considered layouts are based on a number of HTS tapes, which are arranged as five layered structures of twisted tapes wound on a helically slotted core with an external round jacket, and the conductor is designed to target 20 kA at operating conditions (T = 5 K, B = 15 T; or T = 77 K, self-field). With the commercialization of 2G HTS tapes, several options are now available on the market that can meet the ENEA cable specifications. Thus, for a sound design of the ENEA cable, a measurement campaign was launched aiming to determine the critical current, i.e., Ic, of commercial tapes as a function of an external applied field (up to 12 T) at different temperatures (in the 5-77 K range). Transport measurements were performed at 77 K in the high-field region, whereas the low-field and low-temperature critical currents have been determined from magnetization loops measured with a vibrating sample magnetometer system. Within a COMSOL Multiphysics environment, a 2-D finite-element method (FEM) magnetostatic model has been developed, in which a uniform Ic distribution is assumed in the HTS stacks. Both the experimental and FEM results are discussed in terms of cable performance, showing that current commercial tapes can already meet the ENEA cable specifications at T = 5 K, B = 15 T.
IEEE Transactions on Applied Superconductivity | 2010
L. Muzzi; Gianluca De Marzi; Chiarasole Fiamozzi Zignani; L. Affinito; Mathieu Napolitano; R. Viola; Cesar Octavio Dominguez; Luca Bottura; Sandrine Le Naour; D. Richter; Antonio della Corte
We report on the magnetic and transport characterization of different NbTi commercial strands, carried out at variable temperature and magnetic field. From the critical current densities extracted from transport measurements and magnetization cycles we were able to calculate the normalized bulk pinning forces. The curves show good temperature scaling throughout the explored temperature range, and the reduced pinning force can be described by a simple two-components model system. The extension of the 2-components description of the pinning force to an expression for the critical current density gives a very good agreement with experimental measurements over the whole explored B, T range. The model works for all investigated samples, which are different in size, Cu:nonCu ratios, filament diameters and layouts. These results suggest that pinning mechanisms in conventional NbTi strands should be revised, since Nb-Ti composition gradients and grain boundaries seems to play a not negligible role.
IEEE Transactions on Applied Superconductivity | 2016
Laura Savoldi; A. Augieri; Roberto Bonifetto; Pierluigi Bruzzone; Stefano Carli; G. Celentano; Antonio della Corte; Gianluca De Marzi; L. Muzzi; Vincenzo Piras; Roberto Zanino
A thermal-hydraulic model has been developed for the novel cable-in-conduit conductor (CICC) recently proposed by Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), which foresees the use of second-generation REBCO-based coated conductor tapes stacked into twisted grooves slotted into an Al core. A central hole in the Al core provides a low hydraulic impedance channel for the coolant, whereas direct cooling of the tape stacks is achieved through small channels at the bottom of the grooves and other small passages around the stack. The coolant could be either supercritical helium (SHe), for high-field/high-current applications, as in fusion magnets, or liquid nitrogen (LN2), for self-field/lower current requirements. The issues of the thermal-hydraulic performance and optimization of such a CICC are addressed for the first time in this paper. The 4C code is used to develop an adequate model for this complex 3D problem, taking advantage of the 1D nature of the coolant flow. The model, first calibrated and then validated using the results of thermal-hydraulic tests performed in cryogenic conditions at the Center for Research in Plasma Physics (CRPP), is used to evaluate the flow repartition among the different cooling paths in the CICC for SHe at 4.5 K and for LN2 at 77 K. The model is finally used to perform parametric analyses, varying, e.g., the central hole diameter, as well as the size of the grooves at the bottom of the tapes, within the limits imposed by structural constraints, and to assess the cooling capability of the cable.
Advances in Condensed Matter Physics | 2018
Giordano Tomassetti; Gianluca De Marzi; G. Celentano; Francesco Rizzo; A. Augieri; Antonio della Corte
The ENEA superconductivity laboratory developed a novel design for Cable-in-Conduit Conductors (CICCs) comprised of stacks of 2nd-generation REBCO coated conductors. In its original version, the cable was made up of 150 HTS tapes distributed in five slots, twisted along an aluminum core. In this work, taking advantage of a 2D finite element model, able to estimate the cable’s current distribution in the cross-section, a multiobjective optimization procedure was implemented. The aim of optimization was to simultaneously maximize both engineering current density and total current flowing inside the tapes when operating in self-field, by varying the cross-section layout. Since the optimization process involved both integer and real geometrical variables, the choice of an evolutionary search algorithm was strictly necessary. The use of an evolutionary algorithm in the frame of a multiple objective optimization made it an obliged choice to numerically approach the problem using a nonstandard fast-converging optimization algorithm. By means of this algorithm, the Pareto frontiers for the different configurations were calculated, providing a powerful tool for the designer to achieve the desired preliminary operating conditions in terms of engineering current density and/or total current, depending on the specific application field, that is, power transmission cable and bus bar systems.
IEEE Transactions on Applied Superconductivity | 2017
Chiarasole Fiamozzi Zignani; Gianluca De Marzi; Gaia Grimaldi; Antonio Leo; Anita Guarino; A. Vannozzi; Antonio della Corte; S. Pace
Iron-based superconductors are an interesting class of materials that have attracted significant interest during the last years, and which could be employed in a variety of potential applications due to their high upper critical field <italic>H<sub>c2</sub></italic>. In order to exploit the properties of these materials for practical applications, in this paper we explore two different routes for the fabrication of polycrystalline samples belonging to 11-family. In particular, the influence of dedicated heat treatments has been investigated to optimize their overall superconducting properties. Then, we compared the pinning properties of these two types of samples to correlate the fabrication process with the pinning landscape. The final aim is to obtain an increased <italic>T<sub>c</sub></italic> and <italic> H<sub>c2</sub></italic>, as well as an enhanced pinning efficacy, which could lead to higher critical current density <italic>J<sub>c</sub></italic> relevant for practical uses.
IEEE Transactions on Applied Superconductivity | 2017
Gerardo Iannone; A. Saggese; Gianluca De Marzi; Umberto Gambardella
We have investigated magnetization cycles of a MgB2 sphere, 4 mm size, at temperatures of 25, 30, and 35 K up to an applied magnetic field μ0H strength of 3 T. Further to magnetization cycles, we also studied the shift of the magnetization peak position as a function of the maximum applied field for field values between the first penetration field and the full penetration field. In this way, we found a shift of the magnetization peak field position toward a saturation value of the applied field, above which no further shift is observed. The shift of the magnetization peak field position has been observed in YBCO thin films, and ascribed to the magnetization trapped in the granular borders of the material. The same mechanisms may be supposed acting in the MgB2 sphere, provided that the saturated peak of the magnetization curve lies in the μ0H <; 0 region due to the effect of local field B on the critical current Jc(B) in the spherical geometry. This will show up the shift effect in the H <; 0 region. A FEM model with H-formulation has also been implemented, in which the magnetization cycle is taken into account by the power-law E(J) characteristic for the electric field. Our experimental and numerical findings can provide a simple understanding of the observed magnetization cycle in this spherical geometry in saturated and nonsaturated conditions.
ACS Photonics | 2014
O. Limaj; F. Giorgianni; Alessandra Di Gaspare; Valeria Giliberti; Gianluca De Marzi; P. Roy; M. Ortolani; Xiaoxing Xi; Daniel Cunnane; S. Lupi
IEEE Transactions on Applied Superconductivity | 2018
Andrea Masi; C. Alvani; A. Augieri; Mariangela Bellusci; G. Celentano; Gianluca De Marzi; F. Fabbri; Chiarasole Fiamozzi Zignani; Aurelio La Barbera; Franco Padella; Marzia Pentimalli; Enrico Silva; A. Vannozzi; Francesca Varsano
IEEE Transactions on Applied Superconductivity | 2018
Valentina Pinto; Raffaele Lamanna; A. Vannozzi; Achille Angrisani Armenio; Gianluca De Marzi; A. Augieri; Laura Piperno; Giovanni Sotgiu; G. Celentano