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In the last years, a collaboration between the Physics Department of the University of Bologna and the Archaeological Museum of Bologna has been setup in order to examine archaeological artifacts using advanced Nondestructive Tech...
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In the last years, a collaboration between the Physics Department of the University of Bologna and the Archaeological Museum of Bologna has been setup in order to examine archaeological artifacts using advanced Nondestructive Techniques (NDT). In the framework of this collaboration, bronze objects of the Etruscan section have been investigated in the past by means of Digital Radiography (DR) and 3D Computed Tomography (CT) techniques. Important results have been obtained concerning the inner structure and the assembly of the samples as well as the manufacturing techniques. In this work, Egyptian artifacts have been considered to be investigated. The Egyptian collection of the Archaeological Museum of Bologna, with its 3500 objects, is one of the richest in Europe and in Italy. Small mummies have been analyzed by means of an experimental 3D CT system arranged for this purpose at the Physics Department. CT data allows a very fine discrimination among materials with different densities, providing an enormous amount of information not only about mummies, but also about coffins and ornaments eventually included. Moreover, multiple axial images and full 3D visualization of the samples allow to extract numerical measurements of size and position of all the items identified.
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Abstract Apache Spark is probably the most widely adopted framework for developing big-data batch applications and for executing them on a cluster of (virtual) machines. In general, the more resources (machines) one uses, the fast...
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Abstract Apache Spark is probably the most widely adopted framework for developing big-data batch applications and for executing them on a cluster of (virtual) machines. In general, the more resources (machines) one uses, the faster applications execute, but there is currently no adequate means to determine the proper size of a Spark cluster given time constraints, or to foresee execution times given the number of employed machines. One can only run these applications and use her/his experience to size the cluster and predict expected execution times. Wrong estimation of execution times can lead to costly overruns and overly long executions, thus calling for analytic sizing/prediction techniques that provide precise time guarantees. This paper addresses this problem by proposing a solution based on model-checking. The approach exploits a directed acyclic graph (DAG) to abstract the structure of the execution flows of Spark programs, annotates each node (Spark stage) with execution-related data, and formulates the identification of the global execution time as a reachability problem. To avoid the well-known state space explosion problem, the paper also proposes a technique to reduce the size of generated abstract models. This results in a significant decrease in used memory and/or verification time making our approach feasible for predicting the execution time of Spark applications given the resources available. The benefits of the proposed reduction technique are evaluated by using both timed automata and constraint LTL over clocks logic to formally encode and analyze generated models. The approach is also successfully validated on some realistic case studies. Since the optimization is not Spark-specific, we claim that it can be applied to a wide range of applications whose underlying model can be abstracted as a DAG.
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DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6 $$\times $$ × 6 $$\times $$ × 6 m $$^3$$ 3 liquid argon time-proje...
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DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6 $$\times $$ × 6 $$\times $$ × 6 m $$^3$$ 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019–2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.
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The spatial and temporal scales and the geometry of fluid pathways in a collisional orogen are investigated using stable isotope analysis (O, C, and H) and ~(40)Ar/~(39)Ar dating of vein minerals formed at circa 11-16 Ma in the Mo...
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The spatial and temporal scales and the geometry of fluid pathways in a collisional orogen are investigated using stable isotope analysis (O, C, and H) and ~(40)Ar/~(39)Ar dating of vein minerals formed at circa 11-16 Ma in the Mont Blanc and the Aar External Crystalline Massifs. In both massifs ~(40)Ar/~(39)Ar dating of veins adularia provides evidence for progressive crystallization from 16 to 9 Ma, and mainly at 11-12 Ma following veins opening during shear zone activity. The fluid flow duration thus ranges from 4 to 5 Ma in the two massifs. The δ~(18)O values of vein quartz and calcite are similar to those of undeformed crystalline and sedimentary host rocks, suggesting rock buffering, while carbon isotope ratios of vein calcites fall into three compositional groups. A-type veins have δ~(13)C values that are buffered by the Helvetic metasediments, which suggests that these veins formed in a closed system from a locally derived CO_2-rich fluid. The fluid in equilibrium with C-type veins has depleted δ~(13)C values similar to mantle-CO_2, while the intermediate δ~(13)C values of B-type veins suggest mixing between the A-type and C-type fluids. These results are in agreement with crustal- to lithosphere-scale upward vertical fluid flow along vertical shear zones related to the strike-slip system bounding the Adriatic block since 16-20 Ma, connecting a deep-seated fluid to some downward flow in the sedimentary cover of External Crystalline Massifs.
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We review rainfall thresholds for the initiation of landslides world wide and propose new empirical rainfall thresholds for the Central European Adriatic Danubian South-Eastern Space (CADSES) area, located in central and southern ...
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We review rainfall thresholds for the initiation of landslides world wide and propose new empirical rainfall thresholds for the Central European Adriatic Danubian South-Eastern Space (CADSES) area, located in central and southern Europe. One-hundred-twenty-four empirical thresholds linking measurements of the event and the antecedent rainfall conditions to the occurrence of landslides are considered. We then describe a database of 853 rainfall events that resulted or did not result in landslides in the CADSES area. Rainfall and landslide information in the database was obtained from the literature; climate information was obtained from the global climate dataset compiled by the Climate Research Unit of the East Anglia University. We plot the intensity-duration values in logarithmic coordinates, and we establish that with increased rainfall duration the minimum intensity likely to trigger slope failures decreases linearly, in the range of durations from 20 minutes to ～12 days. Based on this observation, we determine minimum intensity-duration (ID) and normalized-ID thresholds for the initiation of landslides in the CADSES area. Normalization is performed using two climatic indexes, the mean annual precipitation (MAP) and the rainy-day-normal (RDN). Threshold curves are inferred from the available data using a Bayesian statistical technique. Analysing the obtained thresholds we establish that lower average rainfall intensity is required to initiate landslides in an area with a mountain climate, than in an area characterized by a Mediterranean climate. We further suggest that for rainfall periods exceeding ～12 days landslides are triggered by factors not considered by the ID model. The obtained thresholds can be used in operation landslide warning systems, where more accurate local or regional thresholds are not available.
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The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary even...
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The Pandora Software Development Kit and algorithm libraries provide pattern-recognition logic essential to the reconstruction of particle interactions in liquid argon time projection chamber detectors. Pandora is the primary event reconstruction software used at ProtoDUNE-SP, a prototype for the Deep Underground Neutrino Experiment far detector. ProtoDUNE-SP, located at CERN, is exposed to a charged-particle test beam. This paper gives an overview of the Pandora reconstruction algorithms and how they have been tailored for use at ProtoDUNE-SP. In complex events with numerous cosmic-ray and beam background particles, the simulated reconstruction and identification efficiency for triggered test-beam particles is above 80% for the majority of particle type and beam momentum combinations. Specifically, simulated 1?GeV/c charged pions and protons are correctly reconstructed and identified with efficiencies of 86.1\(\pm 0.6\)% and 84.1\(\pm 0.6\)%, respectively. The efficiencies measured for test-beam data are shown to be within 5% of those predicted by the simulation.
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A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the O(10)??MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid...
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A primary goal of the upcoming Deep Underground Neutrino Experiment (DUNE) is to measure the O(10)??MeV neutrinos produced by a Galactic core-collapse supernova if one should occur during the lifetime of the experiment. The liquid-argon-based detectors planned for DUNE are expected to be uniquely sensitive to the νe component of the supernova flux, enabling a wide variety of physics and astrophysics measurements. A key requirement for a correct interpretation of these measurements is a good understanding of the energy-dependent total cross section σ(Eν) for charged-current νe absorption on argon. In the context of a simulated extraction of supernova νe spectral parameters from a toy analysis, we investigate the impact of σ(Eν) modeling uncertainties on DUNE’s supernova neutrino physics sensitivity for the first time. We find that the currently large theoretical uncertainties on σ(Eν) must be substantially reduced before the νe flux parameters can be extracted reliably; in the absence of external constraints, a measurement of the integrated neutrino luminosity with less than 10% bias with DUNE requires σ(Eν) to be known to about 5%. The neutrino spectral shape parameters can be known to better than 10% for a 20% uncertainty on the cross-section scale, although they will be sensitive to uncertainties on the shape of σ(Eν). A direct measurement of low-energy νe-argon scattering would be invaluable for improving the theoretical precision to the needed level.
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Measurements of electrons from νe interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection,...
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Measurements of electrons from νe interactions are crucial for the Deep Underground Neutrino Experiment (DUNE) neutrino oscillation program, as well as searches for physics beyond the standard model, supernova neutrino detection, and solar neutrino measurements. This article describes the selection and reconstruction of low-energy (Michel) electrons in the ProtoDUNE-SP detector. ProtoDUNE-SP is one of the prototypes for the DUNE far detector, built and operated at CERN as a charged particle test beam experiment. A sample of low-energy electrons produced by the decay of cosmic muons is selected with a purity of 95%. This sample is used to calibrate the low-energy electron energy scale with two techniques. An electron energy calibration based on a cosmic ray muon sample uses calibration constants derived from measured and simulated cosmic ray muon events. Another calibration technique makes use of the theoretically well-understood Michel electron energy spectrum to convert reconstructed charge to electron energy. In addition, the effects of detector response to low-energy electron energy scale and its resolution including readout electronics threshold effects are quantified. Finally, the relation between the theoretical and reconstructed low-energy electron energy spectra is derived, and the energy resolution is characterized. The low-energy electron selection presented here accounts for about 75% of the total electron deposited energy. After the addition of lost energy using a Monte Carlo simulation, the energy resolution improves from about 40% to 25% at 50 MeV. These results are used to validate the expected capabilities of the DUNE far detector to reconstruct low-energy electrons.
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摘要 :We give a variational Monte Carlo description at T = 0 K of 4He filling under pressure a porous glass within the shadow wave function technique. We have considered as confining media two different smooth pores, one with a circular...
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We give a variational Monte Carlo description at T = 0 K of 4He filling under pressure a porous glass within the shadow wave function technique. We have considered as confining media two different smooth pores, one with a circular cross-section of radius R = 13 ? resembling a Gelsil pore, and the other with a hexagonal cross–section of side S = 14 ? resembling a FSM-16 pore. In all the studied cases the density profiles show a strong layering of the 4He atoms. As the density is increased, solidification takes place layer by layer, starting from the pore wall. Computing the one-body density matrix we are able to estimate the Bose–Einstein condensate fraction, which is still non–zero even when the whole system is in the solid phase.
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