278 research outputs found
Gestione ed economia nei saltus imperiali deltizi
No full textL'esistenza di possedimenti terrieri imperiali nell'area deltizia padana è attestata da un gruppo di iscrizioni funerarie di schiavi e liberti del princeps, e dalla produzione di laterizi bollati delle manifatture dell'imperatore. Dall'analisi di questa documentazione emergono indizi sui metodi di gestione e di produzione di tali possedimenti, e dal confronto con realtà simili emerse in altre regioni, si evidenzia come le tenute imperiali economicamente più rilevanti si estendessero in aree geografiche tradizionalmente molto produttive e al centro di vasti commerci
L'economia del Delta antico: spunti di ricerca.
No full textIl volume comprende tre articoli sull'economia dell'area deltizia padana in età romana. Si affrontano temi come il problema della esistenza o meno di saline lungo la costa adriatica nel tratto fra Ravenna e Adria, si analizzano le risorse naturali della regione soprattutto in rapporto alla presenza di aree boschive o coltivate, si analizzano i laterizi con bollo di produzione imperiale avanzando l'ipotesi che la produzione del II secolo d. C. fosse indirizzata principalmente alla costruzione degli edifici pubblici di Ravenna
INTEFF_TOTEM Project: magneTron sputtering cyclOtron TargEt Manufacturing
No full textINTEFF_TOTEM is a Proof-of-Concept project in the
framework of “Innovazione tecnologica dalla fisica
fondamentale” (INTEFF) program promoted by INFN
Technology Transfer Committee (CNTT). This project is
funded by the Ministry of Economic Development (MISE)
for a period of 18 months and started on February 2021.
The project aims to enhance the INFN patent
no. WO 2019/053570 “Method for obtaining a solid target
for radiopharmaceuticals production”, developed within the
framework of the LARAMED project at LNL. A
technological R&D program to improve the deposition
efficiency of some materials (e.g., Cr, ZnO) on different
substrates (metal and non-metal) with Magnetron Sputtering
(MS) technique is planned. The goal is to limit, as much as
technically achievable, the losses of the starting material,
thus making this technique also attractive for the expensive
isotopically enriched materials, typically used to
manufacture cyclotron solid targets for the production of
medical radionuclides. The current estimated Technology
Readiness Level (TRL) of this patent is 4. At the end of the
project, to evaluate the developed technology, some targets
will be irradiated with the proton beam of the medical
cyclotron available at the S. Cuore Don Calabria Hospital
(SCDCH) in Negrar, (VR). With such a planned
improvement, we expect to achieve a TRL of 6. Moreover,
a technological development of another INFN patent held
by LARAMED group (no. WO 2019/220224 A1, “A
method and a target for the production of 67Cu”) is strictly
related to this project. The manufacturing of the first step
towards the realization of a ZnO multilayer target for 67Cu
production with a high energy cyclotron (e.g., the BEST 70p
at LNL) is foreseen using both MS and Spark Plasma
Sintering (SPS) techniques. The INTEFF_TOTEM project
is carried out in the framework of the LARAMED target
development activities [1] and in collaboration with the
Servizio Tecnologia delle Superfici e Superconduttività at
the LNL
Effective Theory and Breakdown of Conformal Symmetry in a Long-Range Quantum Chain
No full textWe deal with the problem of studying the symmetries and the effective theories of long-range models around their critical points. A prominent issue is to determine whether they possess (or not) conformal symmetry (CS) at criticality and how the presence of CS depends on the range of the interactions. To have a model, both simple to treat and interesting, where to investigate these questions, we focus on the Kitaev chain with long-range pairings decaying with distance as power-law with exponent alpha. This is a quadratic solvable model, yet displaying non-trivial quantum phase transitions. Two critical lines are found, occurring respectively at a positive and a negative chemical potential. Focusing first on the critical line at positive chemical potential, by means of a renormalization group approach we derive its effective theory close to criticality. Our main result is that the effective action is the sum of two terms: a Dirac action S-D, found in the short-range Ising universality class, and an "anomalous" CS breaking term SAN. While SD originates from low-energy excitations in the spectrum, SAN originates from the higher energy modes where singularities develop, due to the long-range nature of the model. At criticality SAN flows to zero for alpha > 2, while for alpha < 2 it dominates and determines the breakdown of the CS. Out of criticality SAN breaks, in the considered approximation, the effective Lorentz invariance (ELI) for every finite alpha. As alpha increases such ELI breakdown becomes less and less pronounced and in the short-range limit alpha -> infinity the ELI is restored. In order to test the validity of the determined effective theory, we compared the two-fermion static correlation functions and the von Neumann entropy obtained from them with the ones calculated on the lattice, finding agreement. These results explain two observed features characteristic of long-range models, the hybrid decay of static correlation functions within gapped phases and the area-law violation for the von Neumann entropy. The proposed scenario is expected to hold in other long-range models displaying quasiparticle excitations in ballistic regime. From the effective theory one can also see that new phases emerge for alpha < 1. Finally we show that at every finite a the critical exponents, defined as for the short-range (alpha -> infinity) model, are not altered. This also shows that the long-range paired Kitaev chain provides an example of a long-range model in which the value of a where the CS is broken does not coincide with the value at which the critical exponents start to differ from the ones of the corresponding short-range model. At variance, for the second critical line, having negative chemical potential, only SAN (So) is present for 1 < alpha < 2 (for alpha > 2). Close to this line, where the minimum of the spectrum coincides with the momentum where singularities develop, the critical exponents change where CS is broken. © 2016 Elsevier Inc
Superconductive Performance of the Deposited High-β and Tested Medium-β QWR Cavities of the ALPI Linac
No full text8 high-β Nb/Cu superconductive QWR cavities should be
coated for the ALPI upgrade in the framework of the SPES
facility. The QWR cavities should require specific
superconductive performance to be assembled in the ALPI
linac.
RF test cold measurements are used for evaluation of the
coated Nb/Cu quality. Meanwhile, verification of the QWRs
superconductive properties, which are currently used in the
ALPI on-line activity, is also made with RF measurements.
Methodology and results of the sputtered QWRs RF
measurements will be described in this paper. In particular,
cold test results of the ALPI cryostat 7 medium-β QWR
cavities will be mentioned
Tubicines, cornicines e bucinatores nella documentazione epigrafica,
No full textSi analizzano alcune iscrizioni che menzionano suonatori di strumenti a fiato in ambito civile, a Roma e in altri municipi dell'Italia romana. Poichè la 'tuba' rinvenuta durante gli scavi archeologici del vicus di Voghenza (FE) non pare ricollegabile alle manifestazioni della vita cittadina, si ipotizza che la sua presenza sia più probabilmente legata all'insediamento di militari e veterani attestati nell'area deltizia del Po
Topological massive Dirac edge modes and long-range superconducting Hamiltonians
No full textWe discover novel topological effects in the one-dimensional Kitaev chain modified by long-range Hamiltonian deformations in the hopping and pairing terms. This class of models display symmetry-protected topological order measured by the Berry/Zak phase of the lower-band eigenvector and the winding number of the Hamiltonians. For exponentially decaying hopping amplitudes, the topological sector can be significantly augmented as the penetration length increases, something experimentally achievable. For power-law decaying superconducting pairings, the massless Majorana modes at the edges get paired together into a massive nonlocal Dirac fermion localized at both edges of the chain: a new topological quasiparticle that we call topological massive Dirac fermion. This topological phase has fractional topological numbers as a consequence of the long-range couplings. Possible applications to current experimental setups and topological quantum computation are also discussed
Il fenomeno carsico del comprensorio Monte San Giorgio – Orsa – Pravello (Svizzera – Italia): censimento e descrizione delle cavità
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