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Analytical solutions for seismic responses of the tunnel in a shaft-tunnel junction under transverse excitations
No full textThe analytical solutions are proposed for seismic responses of the tunnel in a shaft-tunnel junction under transverse excitations. The vertical shaft in the junction is regarded as a rigid body. The tunnel is simplified into a massless beam. It is connected to the shaft perpendicularly in a fixed end. The surrounding soil is represented by distributed springs and dashpots. Displacements of the tunnel can be obtained by adopting displacements of the shaft as boundary conditions for the governing equations. Thereby, analytical solutions for the three major internal forces of the tunnel are derived. Validity of the proposed solutions is examined by finite element method. The comparison shows that the analytical solutions could provide accurate results of internal forces of the tunnel at the portion near the junction. However, they become less accurate when the distance to the shaft increases. Relations between the internal forces and physical parameters of the soil-shaft-tunnel system are discussed. Distributions of the internal forces along the tunnel axis are highly dependent on the stiffness of the soil and the tunnel, while amplitudes of the internal forces are also determined by the amount of shaft-soil relative displacements. When the connection between shaft and tunnel is replaced by a pin joint as a conceptual aseismic measure, the maximum shearing force and the maximum bending moment of the tunnel would be both significantly reduced. © 2019 Elsevier Lt
Comitato Scientifico Art Festival Internazionale 2019 Torri in Festa Torri in Luce. IX Edizione Isola d'Ischia.
No full textConclusioni
No full textIl Convegno ha avuto ad oggetto profili costituzionalistici e penalistici del contrasto al terrorismo. Nella sessione penalistica si sono trattati i temi della definizione di terrorismo, delle misure di prevenzione, dei reati d'opinione, delle fattispecie associative e delle condotte preparatori
Membro del Comité de Redaction e del Comité de lecture della Rivista Dialogues d'Histoire ancienne
No full textAdiabatic Vlasov theory of ultrastrong femtosecond laser pulse propagation in plasma.The scaling of ultrarelativistic quasi-stationary states: spikes, peakons, and bubbles
No full textThe interaction of an ultrashort (femtosecond), pancake-shaped laser pulse with underdense unmagnetized plasma is studied analytically and numerically in a regime with ultrarelativistic electron jitter velocities. The adiabatic evolution of the quasistationary electron distribution function is resolved by following particles along their nonlinear trajectories in phase space. It is estimated that under typical laser-plasma accelerator conditions, the quasistationary distribution is established after the pulse has penetrated . 1mm into the plasma. The main particle eect is found to be the beam loading associated with the electrons re ected from the maxima of the eective potential, a fraction of which can also be entrapped in the time dependent potential minima. Owing to the relativistic mass increase, their participation in the plasma dynamics is reduced. The number density of re ected particles is exponentially small for nonrelativistic electron temperatures, but at the wavebreak it can become comparable to the density of the background plasma if the temperature of electrons exceeds several percent of their rest energy m0c2. Numerical calculations in the presence of beam loading and in the strong intensity regime, based on the three-timescale approximation [1], reveal the creation of a bubble in the electron density, along with the steepening and the breaking of the nonlinear Langmuir wake that occurs simultaneously with the creation of a sharp spike in the distribution function and a peak in the electron density, located at the position of the wavebreak
Fintech, filiere di valore e piattaforme digitali. Verso la costruzione di un nuovo paradigma regolamentare e di vigilanza
No full textL’ascesa inarrestabile delle piattaforme digitali in ambito finanziario solleva domande sulla natura delle attività e dei servizi offerti e di come esse generano il loro valore. L’economia delle piattaforme sfugge a consuete definizioni. Ciò che in particolar modo distingue i nuovi operatori digitali da quelli tradizionali è la loro intrinseca capacità di trasformare i mercati, le imprese che producono beni e servizi e le relative transazioni. Questo tumultuoso processo di innovazione rende, pertanto, necessarie misure di manutenzione delle regole vigenti, che altrimenti diverrebbero obsolete, e sussume come improcastinabile un intervento dei regolatori volto a favorire la standardizzazione e le interoperabilità, in funzione della promozione ordinata del mercato stesso. L’indirizzo attendista (wait and see) fino ad ora assunto dai policy maker (generativo di rischi) si infrange con interessi contrapposti, che sono spesso di sistema. Si pensi, innanzitutto, all’imprescindibile esigenza di garantire stabilità finanziaria al mercato. O, ancora, alla necessità di favorire il raggiungimento di un effettivo level playing field escludendo dal mercato quegli operatori dallo scarso valore reputazionale. Come la relazione intende dimostrare, la creazione di un “Mercato unico tecnologico dei servizi finanziari” richiede un approccio regolamentare innovativo e al “passo con i tempi”; così pure, in un’ottica di cooperazione transfrontaliera, i modelli di vigilanza vanno ripensati per comprendere appieno i “messaggi” e le “novità” che l’esperienza concreta offre
Laparoscopic and robotic-assisted repair of retrocaval ureter in children: a multi-institutional comparative study with open repair.
No full textPURPOSE:
This retrospective study aimed to report a multi-institutional experience with laparoscopic and robotic-assisted repair of retrocaval ureter in children and to compare outcome of minimally invasive surgery (MIS) with open repair.
METHODS:
The records of all children, who underwent MIS and open repair of retrocaval ureters in six international pediatric urology units over a 5-year period, were retrospectively collected. Data were grouped according to the operative approach: a laparoscopic group (G1) included five patients, a robotic-assisted group (G2) included four patients, and an open group (G3) included three patients. The groups were compared in regard to operative and postoperative outcomes.
RESULTS:
At follow-up, all patients (one G1 patient after redo-surgery) reported complete resolution of symptoms and radiologic improvement of hydronephrosis and obstruction. In regard to postoperative complications, one G1 patient developed stenosis of anastomosis and needed re-operation with no further recurrence (IIIb Clavien). G2 reported the lowest average operative time (135 min) compared to G1 (178.3 min) and G3 (210 min). MIS (G1-G2) reported a significantly better postoperative outcome compared to open repair (G3) in terms of analgesic requirements, hospitalization, and cosmetic results.
CONCLUSIONS:
The study outcomes suggest that MIS should be the first choice for retrocaval ureter because of the minimal invasiveness and the better cosmetic outcome compared to open surgery. Furthermore, our results showed that robotic-assisted reconstruction was technically easier, safer, and quicker compared to laparoscopic repair, and for these reasons, it should be preferentially adopted, when available
Land use and urban sustainability assessment: a 3D-GIS application to a case study in Gozo
No full textBalancing urban growth and natural resource availability has been recognized as the main challenge of the 21st century from the strategic documents adopted by the recent World Summits. Agenda 21 advocates sustainable land use, as soil is a crucial natural resource to reduce urban vulnerability due e.g. to climate change, energy saving, and natural disasters. In this perspective, this paper aims at supporting local decision makers in identifying the portions and the buildings of an urban area most susceptible to transformation, in order to promote a sustainable land use according to physical and functional characteristics. The proposed methodology combines the 3D modeling of urban settlements and the adoption of the performance-based approach by the urban transformation government, in order to guarantee the satisfaction of the supply–demand ratio through a compatible balance between urban growth dynamics and the overall urban efficiency. The test area was Gozo island, where a significant urban transformation will occur as a consequence of the new Malta-Gozo tunnel construction