DTT - Divertor Tokamak Test facility: A testbed for DEMO

The effective treatment of the heat and power exhaust is a critical issue in the road map to the realization of the fusion energy. In order to provide possible, reliable, well assessed and on-time answers to DEMO, the Divertor Tokamak Test facility (DTT) has been conceived and projected to be carried out and operated within the European strategy in fusion technology. This paper, based on the invited plenary talk at the 31st virtual SOFT Conference 2020, provides an overview of the DTT scientific proposal, which is deeply illustrated in the 2019 DTT Interim Design Report

DTT - Divertor Tokamak Test facility - Interim Design Report

The “Divertor Tokamak Test facility, DTT” is a milestone along the international program aimed at demonstrating – in the second half of this century – the feasibility of obtaining to commercial electricity from controlled thermonuclear fusion. DTT is a Tokamak conceived and designed in Italy with a broad international vision. The construction will be carried out in the ENEA Frascati site, mainly supported by national funds, complemented by EUROfusion and European incentive schemes for innovative investments. The project team includes more than 180 high-standard researchers from ENEA, CREATE, CNR, INFN, RFX and various universities. The volume, entitled DTT Interim Design Report (“Green Book” from the colour of the cover), briefly describes the status of the project, the planning of the design future activities and its organizational structure. The publication of the Green Book also provides an occasion for thorough discussions in the fusion community and a broad international collaboration on the DTT challenge

On the Collapse of a Masonry Tower Subjected to Earthquake Loadings

Some early results of a research study on the behaviour of masonry towers under the seismic actions are illustrated. The results regard analysis of the so-called "Tower of Matilde", the bell tower of the Santa Maria e San Genesio Cathedral in the medieval town of San Miniato, near Pisa (Italy). Over the centuries, this tower has undergone numerous consolidation operations and modifications: originally built as a watch tower within the medieval city walls, it was finally incorporated as a bell tower into the Cathedral. Its current layout makes it particularly susceptible to the dynamic actions consequent to the motion of the bells [1] [2] [3], and, probably, to seismic actions as well. Such a hypothesis seems to be to confirmed by the results of these first linear and collapse analyses, performed by considering earthquakes comparable to those actually expected in the seismic area of San Miniato

Iterative channel estimation for non-binary LDPC-coded OFDM signals

This work deals with the issue of channel estimation in the context of non-binary LDPC-coded OFDM systems over doubly selective multipath channels. In particular, we show how to derive an iterative Wiener-filter-based estimation method using both time and frequency channel correlation and considering the particular characteristics of the channel code. The proposed algorithm can use either soft information or hard decisions fed back by the decoder to refine the channel estimation, so as to improve the system performance at the expense of an increased receiver complexity. Simulation results under typical working conditions are presented to compare the performance of the proposed method with respect to classical techniques.</jats:p

The impact of conditioned attenuation statistics on the performance of VCM techniques for Earth Observation Satellites in LEO orbit

In the frame of the “Advanced Techniques for High Data Rate Links for Earth Exploration Satellites" study, ESA Contract n. 22455/09/NL/JK, a set of SW was developed to allow the system designer computing the end-to-end performance of the data downlink architecture of Earth Observation satellite in LEO orbit when using Variable Coding Modulation (VCM) techniques and comparing it against the achievable figure when Constant Coding Modulation (CCM) is used. In particular, the SW implements modulation and coding described in the CCSDS standard, pre-distortion techniques, and on-ground algorithms for mitigation of channel contribution to dual-polarization transmission. Moreover, the SW allows the user selecting the main mission parameters (e.g. orbit, ground station, link availability, non-linear amplifier, on-board RF filters, EIRP etc..) according to its customized scenario. VCM demonstrates the improvement of downlink data rate of Earth Observation satellite in LEO orbit system performance, by adapting case-by-case the coding/modulation scheme, especially for systems characterized by a ground station network based on different climate areas (e.g. Mediterranean, Near Polar, Desert Ground station). For a K-Band system, considering the typical availability requirement for Earth Observation satellite data downlink (i.e. 99.5%) a special care shall be paid to the atmospheric propagation; it is well known that rain attenuation is the most important impairments for probability lower than about 1%. The total attenuation exceeded for 0.1% of the average year in Ka band can be several dBs larger than attenuation exceeded for the same time percentage during non-rainy periods (about 95% of the total year for European climate). The high difference between atmospheric propagation in rain and non-rainy condition is worth to be further analysed: the disadvantage of dimensioning the link on the average year is to have a reduced throughput even during the clear-sky (i.e. non rainy) periods characterized by low values of atmospheric attenuation