200 research outputs found
A Parallel Simulator of Quench in Superconducting Magnets
No full textIn a superconducting magnet the null resistivity of the cable allows to run a very intense electrical current without dissipating heat. During operation, a region of the superconducting wire can turn to normal state (quench) with possible damage due to intense heat dissipation. Quench simulation is thus a necessary step
during magnet design; it is a multi-physics computational problem that ends up very easily with tens of millions of equations in as many unknowns. In this paper we attempt an HPC approach for quench simulation
L'enigma epigrafico di Barbola
No full textIn 1878 the front panel of a Roman sarcophagus was found in the basilica of SS. Maria and Donato in Murano. The artefact, which dates to the 3rd century AD, had first been reused as a grave marker in the early Middle Ages and was later turned upside down and employed in the floor of the church, which dates to 1141. The author of the discovery was the abbot Vincenzo Zanetti, director of the Murano City Museum, who first proposed an interpretation for the text that is inscribed in the tabula ansata in the centre of the sarcophagus. Several other exegetical attempts have followed, none of which seems fully convincing. This article offers a different transcription of the epigraphic document, based on a careful autopsy of the text and, especially, on the observation of the relevant role played by the cross that occupies the centre of the artefact. This new reading is confirmed by the contents of the so far unpublished correspondence exchanged between Zanetti and Giovanni Battista de Rossi immediately following the discovery of the sarcophagus, whose full transcription and analysis are given for the first time
Iscrizioni esposte in contesti di reimpiego: l'esempio veneziano
No full textL'articolo indaga gli ambiti di applicazione della nozione di «scrittura esposta», inizialmente elaborata da Armando Petrucci e solitamente applicata ai contesti originari per i quali le iscrizioni furono concepite. Attraverso un'esemplificazione diacronica di spolia epigrafici provenienti da Venezia e dalle isole della laguna circostante, l'autore si interroga sulle motivazioni del riutilizzo delle iscrizioni antiche, nonché sugli esiti di tale fenomeno. In particolare, sono notevoli i casi in cui la scrittura esposta delle iscrizioni reimpiegate generò nuova scrittura esposta, mentre in altre circostanze la scrittura fu deliberatamente nascosta, dimostrando così lo scopo puramente funzionale di quei reimpieghi.This article investigates the notion of «exhibited writing» («scrittura esposta»), first propounded by Armando Petrucci and usually applied to the original contexts for which inscriptions were conceived. Building on a cross-temporal selection of epigraphic spolia from Venice and the islands of the nearby lagoon, the author explores the motives for reusing ancient inscriptions, as well as the results of this phenomenon. Especially noteworthy are the cases when the exhibited writing of reused inscriptions generated new exhibited writing, while in other circumstances writing was deliberately hidden, thus showing that those spolia were only useful as structural elements
"Conclave plenum inscriptionibus quae per cancellos a limine solum salutare licuit". Le epigrafi delle raccolte di Palazzo Grimani a Venezia
No full textQuesto è il primo studio interamente dedicato alle iscrizioni antiche transitate per le
raccolte antiquarie della famiglia patrizia veneziana dei Grimani di Santa Maria Formosa.
L’esame di documenti editi e inediti ha consentito finora di individuare circa
45 epigrafi latine e greche che furono ospitate nel loro palazzo tra i secoli XVI e XIX.
Grazie all’analisi dei canali di acquisizione e dispersione del celebre museo privato dei
Grimani è stato possibile identificare la località di provenienza e quella di attuale conservazione
di molti reperti, recuperando in tal modo importanti fonti per lo studio della
storia antica.This article is the first study entirely devoted to the ancient inscriptions that once belonged
to the antiquarian collections of the patrician Venetian family of the Grimani
di Santa Maria Formosa. By examining a variety of published and unpublished documents,
it has so far been possible to identify about 45 Greek and Latin inscriptions that
were exhibited in their palace from the 16th to the 19th centuries. The analysis of the
dynamics through which their celebrated private museum was acquired and later dispersed
has enabled the author to identify the geographic origin and the current location
of numerous objects, thus furnishing crucial information on some important sources for
the study of ancient history
Epigraphic Database Falsae (EDF): Genesis, Structure, Critical Issues and Potential Applications
No full textThis article explores the hermeneutic capabilitiesof the digital resource Epigraphic Database Falsae (EDF: http://edf.unive.it) through an analytical approach. In particular, the author examines the genesis of the database, its architecture and its limits, as well as some potential improvements and innovations for future projects
Space Safety and Human Performance
No full textSpace Safety and Human Performance provides a comprehensive reference for engineers and technical managers within aerospace and high technology companies, space agencies, operators, and consulting firms. The book draws upon the expertise of the world’s leading experts in the field and focuses primarily on humans in spaceflight, but also covers operators of control centers on the ground and behavior aspects of complex organizations, thus addressing the entire spectrum of space actors.
During spaceflight, human performance can be deeply affected by physical, psychological and psychosocial stressors. Strict selection, intensive training and adequate operational rules are used to fight performance degradation and prepare individuals and teams to effectively manage systems failures and challenging emergencies. The book is endorsed by the International Association for the Advancement of Space Safety (IAASS)
The Limits of Space Radiation Magnetic Shielding: An Updated Analysis
No full textA major problem of long-duration manned missions in the deep space is the flow of high energy charged particles of solar (SPE) and galactic (GCR) origin. SPE has short duration but can be extremely intense and can lead to acute, even lethal, effects. GCR flow is much less intense but is continuous, isotropic, and more energetic; it increases the risk of carcinogenesis and can affect the nervous and cardiovascular systems, restricting the endurance of missions to few months. It is commonly believed that the problem of space radiation can be solved by surrounding the spacecraft habitats with large superconducting magnets, even though a considerable technological effort would be required. However, magnetic shielding has several basic limitations, which restrict the reduction of the radiation dose: they range from the biological effect of the particles in the high region of the GCR spectrum, higher than the shield cutoff energy, to the generation of secondary particles due to the interaction of cosmic rays with magnet and spacecraft materials. The physical and technological constraints of space radiation magnetic shields are discussed in this paper. Despite such limitations, a superconducting magnet could completely eliminate the risk due to SPE. Moreover, it could reduce the GCR adsorbed dose enough to make acceptable the risk of developing long term diseases after a return trip to Mars
CLIQ Protection Design for the Graded Nb-Sn Research Racetrack Dipole Demonstrator (R2D2)
No full textInternational audienceThe Research Racetrack Dipole Demonstrator (R2D2) is being studied as a demonstrating magnet for future FCC magnets. The R2D2 is meant to prove the feasibility of grading in block-coil NbSn dipoles and explore quench behaviors at a very high current. This short model provides an opportunity to study quench protection concepts which will be needed for the full-scale FCC magnets. Both quench heaters and CLIQ (coupling loss induced quench) are under study. This paper presents the research work on the CLIQ protection. The work includes CLIQ design methods and configurations, and comparative studies of various CLIQ configurations for maximizing the CLIQ effectiveness. The results show that the most effective CLIQ configuration is able to quench 80% of the coil turns at the nominal current within 3 ms, leaving 20 ms for detection and validation time while keeping the maximum hotspot temperature within 350 K. The study shows that protection of R2D2 using only CLIQ may be feasible under certain assumptions
Space Safety and Human Performance
No full textSpace Safety and Human Performance provides a comprehensive reference for engineers and technical managers within aerospace and high technology companies, space agencies, operators, and consulting firms. The book draws upon the expertise of the world's leading experts in the field and focuses primarily on humans in spaceflight, but also covers operators of control centers on the ground and behavior aspects of complex organizations, thus addressing the entire spectrum of space actors. During spaceflight, human performance can be deeply affected by physical, psychological and psychosocial stressors. Strict selection, intensive training and adequate operational rules are used to fight performance degradation and prepare individuals and teams to effectively manage systems failures and challenging emergencies. The book is endorsed by the International Association for the Advancement of Space Safety (IAASS)
CLIQ Protection Design for the Graded NbSn Research Racetrack Dipole Demonstrator (R2D2)
No full textThe Research Racetrack Dipole Demonstrator (R2D2) is being studied as a demonstrating magnet for future FCC magnets. The R2D2 is meant to prove the feasibility of grading in block-coil Nb3Sn dipoles and explore quench behaviors at a very high current. This short model provides an opportunity to study quench protection concepts which will be needed for the full-scale FCC magnets. Both quench heaters and CLIQ (coupling loss induced quench) are under study. This paper presents the research work on the CLIQ protection. The work includes CLIQ design methods and configurations, and comparative studies of various CLIQ configurations for maximizing the CLIQ effectiveness. The results show that the most effective CLIQ configuration is able to quench 80% of the coil turns at the nominal current within 3 ms, leaving 20 ms for detection and validation time while keeping the maximum hotspot temperature within 350 K. The study shows that protection of R2D2 using only CLIQ may be feasible under certain assumptions.Post-print / Final draf
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