ABSTRACT
Two meteorite pieces have been recovered in Italy, near the town of Cavezzo (Modena), on 2020 January 4th. The associated fireball was observed on the evening of New Year’s Day 2020 by eight ...all-sky cameras of the PRISMA fireball network, a partner of FRIPON. The computed trajectory had an inclination angle of approximately 68° and a velocity at infinity of 12.8 km s−1. Together with the relatively low terminal height, estimated as 21.5 km, those values were indicating the significant possibility of a meteorite dropping event, as additionally confirmed by the non-zero residual total mass. The strewn-field was computed taking into account the presence of two bright light flashes, revealing that the meteoroid had been very likely subject to fragmentation. Three days after the event, two samples, weighing 3.1 and 52.2 g, were collected as a result of a dedicated field search and thanks to the involvement of the local people. The two pieces were immediately recognized as freshly fallen fragments of meteorite. The computed orbital elements, compared with the ones of known Near-Earth Asteroids from the NEODyS database, are compatible with one asteroid only; 2013 VC10. The estimated original mass of the meteoroid, 3.5 kg, and size, approximately 13 cm, is so far the smallest among the current 35 cases in which meteorites were recovered from precise strewn-field computation thanks to observational data. This result demonstrates the effectiveness of accurate processing of fireball network data even on challenging events generated by small size meteoroids.
The Divertor Tokamak Test (DTT) facility is a fusion device under construction in Italy. The mission of DTT is to test alternative divertor concepts under integrated physics and technological ...conditions that can reliably be extrapolated to DEMO. Due to the plasma core characteristics with relevant edge and scrape-off layer (SOL) parameters and a wall entirely in tungsten (W), DTT will provide an extensive set of information useful to select the most appropriate strategy for the power exhaust in DEMO. Several divertors, which may differ in design or/and technologies or/and poloidal profile, will be tested during the life of the machine. The first divertor to be installed will have to accommodate a multitude of strike points, located at various positions according to the different magnetic configurations, which will be tested in the first operational phases of the machine with the aim to identify the most promising. The first divertor will not test innovative technological solutions but will mainly take advantage of the technologies already qualified for the ITER divertor production. Thus, the entire divertor plasma-facing surface is designed to be used as targets: it will be made of W monoblocks joined on CuCrZr pipes (plasma-facing units, PFUs) similar to the ITER targets. With the purpose to increase the flexibility in operational scenarios by maximizing the allowable thermal load for the PFUs, the possibility of using monoblocks with a plasma side reduced thickness was investigated. By reducing the thickness of the armor, it is possible to limit plastic deformation of the monoblock and to preserve the characteristics of the plasma-facing surface during the component lifetime. A thickness between 3 and 4 mm is compatible both the erosion estimates in the DTT divertor area and the manufacturing constraints and therefore proposed for the DTT PFUs. Several mock-ups based on monoblock design were in the past tested under thermal fatigue, confirming the reliability of the monoblock design and the manufacturing processes, but with larger armor thicknesses (6-8 mm). The experimental verification of the monoblock performance with the proposed reduced thickness has been verified in the GLADIS facility at IPP Garching with a thermal load of 20 MW/m<inline-formula> <tex-math notation="LaTeX">^{2}</tex-math> </inline-formula> applied for 1000 cycles of 10 s. The results showed the absence of plastic deformation and negligible increase in surface roughness.
The main mission of the divertor tokamak test (DTT) facility is to study advanced solutions for the power exhaust issue in view of a fusion power plant. In this respect, a significant amount of heat ...is expected to be absorbed by the first wall (FW) during operation. Therefore, the DTT FW is designed to be an actively water-cooled system. A proper hydraulic model is needed for the development of a cooling architecture of the system able to fulfill the requirements of operational safety under thermal loads and compliance with the DTT plant specifications. The present study aims to address this challenge, offering practical inputs for further optimization. Based on the existing conceptual design, the cooling circuits have been setup inside the plasma-facing components (PFCs). In this phase, empirical equations and hydraulic simulations have been adopted to investigate the hydraulic behavior of the modules that make up the FW and to evaluate the main design parameters, namely, velocity and pressure drops in the cooling channels. The outcome of such analysis demonstrated that the current design of the FW system complies with the imposed requirements. Moreover, operating flexibility has been demonstrated by identifying a proper range of the mass flow rate for each subsystem. Therefore, the models implemented in this study and the obtained findings prove to be suitable to support the next activities of engineering design of the FW.
The simplest delay differential equation describing the dynamics of non-lethal infectious diseases in a fixed-size population is extended to include the incubation period, as an additional delay ...parameter. It is observed that these types of deterministic models consist of one delay differential equation, whereas standard SIR and SEIR models consist of two and three ordinary differential equations, respectively. The extended model presents interesting peculiarities as, for example, initial oscillatory patterns in the curve counting the infectious individuals. A comparison of the doubly delayed differential equation with the standard SEIR model is made. It is argued that self-sustained oscillations, which are intrinsic properties of models with time delay, have to be taken into account in designing optimal epidemic containment strategies.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract Rather interesting trigonometric equations arise when considering a Josephson junction obtained by embedding a Pac-Man shaped superconducting island in between two superconducting ...electrodes. In the present work we unfold these equations, written in terms of the superconducting phase difference between the two electrodes, and find the current-phase relation and the maximum superconducting current of the Josephson junction network. The solution of the trigonometric equations defining the superconducting current state of the system can be proposed to advanced high-school students or to undergraduate students in an interdisciplinary lecture.
The divertor tokamak test (DTT) facility is currently in the design stage and in the initial phase of construction at the research center ENEA Frascati. The DTT facility aims at searching integrated ...solutions for the power exhaust issue maintaining plasma performances compatible with future fusion devices. For this reason, the first DTT divertor was designed to accommodate different magnetic configurations: in particular other than single null (SN), the compatibility with X-divertor (XD) and negative triangularity (NT) with different leg lengths was ensured. To accommodate the strike point positions of the different magnetic equilibria, all plasma facing surfaces (i.e., inner and outer vertical targets, as well as the dome) have to be entirely made of tungsten (W) monoblocks. At the same time, to leave more space to the divertor legs, it was decided to design a dome with a flat shape. These two factors along with the armor with W monoblock and the flat shape have required finding ad hoc technological solutions for the plasma facing units (PFUs) of the dome with the need of a research and qualification phase. Above all, a W flat tiles (FTs) design was required at the inner dome end, where the copper cooling pipes turn by 90<inline-formula> <tex-math notation="LaTeX">^{\circ}</tex-math> </inline-formula>. The FT segment covers only a small length of the PFU (<inline-formula> <tex-math notation="LaTeX">\sim</tex-math> </inline-formula>40 mm), and the goal is to join both monoblock and FT segments to the pipe in a single manufacturing process. The technique used is the hot radial pressing (HRP), which has been developed in ENEA and qualified for the manufacturing of the ITER inner vertical target.
This article describes the solutions investigated for the design of the support and fixation systems of the first wall (FW) to the vacuum vessel (VV) at both inboard and outboard sides, in order to ...define their engineering design in compliance with the other involved systems of the divertor tokamak test (DTT) facility: VV, diagnostics, remote handling (RH), and plasma physics. The aim is to engineer them to cope with the electromagnetic (EM) loads resulting from disruption events (VDE and MD) or from discharges occurring in the coils (i.e., toroidal field coils fast discharge).
The structural flexibility of RNA underlies fundamental biological processes, but there are no methods for exploring the multiple conformations adopted by RNAs in vivo. We developed cross-linking of ...matched RNAs and deep sequencing (COMRADES) for in-depth RNA conformation capture, and a pipeline for the retrieval of RNA structural ensembles. Using COMRADES, we determined the architecture of the Zika virus RNA genome inside cells, and identified multiple site-specific interactions with human noncoding RNAs.
The onset of double-diffusive convection in horizontal porous layers filled by an electrically conducting fluid embedded in a magnetic field, is investigated on taking into account of Soret ...phenomenon. Sufficient conditions guaranteeing the onset of steady or oscillatory convection in a closed algebraic form are obtained. Conditions guaranteeing that Hopf convection in the absence of Soret phenomenon, turns into steady convection by the Soret parameter, have been found.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Currently, surgeons in operating rooms are forced to focus their attention both on the patient’s body and on flat low-quality surgical monitors, in order to get all the information needed to ...successfully complete surgeries. The way the data are displayed leads to disturbances of the surgeon’s visuals, which may affect his performances, besides the fact that other members of the surgical team do not have proper visual tools able to aid him. The idea underlying this paper is to exploit mixed reality to support surgeons during surgical procedures. In particular, the proposed experimental setup, employed in the operating room, is based on an architecture that put together the Microsoft HoloLens, a Digital Imaging and Communications in Medicine (DICOM) player and a mixed reality visualization tool (i.e., Spectator View) developed by using the Mixed Reality Toolkit in Unity with Windows 10 SDK. The suggested approach enables visual information on the patient’s body as well as information on the results of medical screenings to be visualized on the surgeon’s headsets. Additionally, the architecture enables any data and details to be shared by the team members or by external users during surgical operations. The paper analyses in detail advantages and drawbacks that the surgeons have found when they wore the Microsoft HoloLens headset during all the ten open abdomen surgeries conducted at the IRCCS Hospital “Giovanni Paolo II” in the city of Bari (Italy). A survey based on Likert scale demonstrates how the use of the suggested tools can increase the execution speed by allowing multitasking procedures, i.e., by checking medical images at high resolution without leaving the operating table and the patient. On the other hand, the survey also reveals an increase in the physical stress and reduced comfort due to the weight of the Microsoft HoloLens device, along with drawbacks due to the battery autonomy. Additionally, the survey seems to encourage the use of DICOM Viewer and Spectator View both for surgical education and for improving surgery outcomes. Note that the real use of the conceived platform in the operating room represents a remarkable feature of this paper, since most if not all the studies conducted so far in literature exploit mixed reality only in simulated environments and not in real operating rooms. In conclusion, the study clearly highlights that, despite the challenges required in the forthcoming years to improve the current technology, mixed reality represents a promising technique that will soon enter the operating rooms to support surgeons during surgical procedures in many hospitals across the world.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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