749 research outputs found
Innovative Uses of Rain Screen Cladding. CFD and Gas Dispersion Analysis of a Prototype
Abstract In this work, both CFD and CH 4 dispersion analysis in rain screen cladding were carried out, in order to reduce the visual impact of Natural Gas distribution network in civil buildings ensuring high safety standards. In the first part of the work it was conducted the parametric analysis in order to identify the main physical parameters that influence the air velocity in air-gap. Subsequently, CFD simulations were carried out in order to evaluate how the geometric and constructive characteristics can influence the air velocity inside the cavity. In particular, were realized both 2D and 3D models, and was used Ansys Fluent 6.3 software. Finally, Natural Gas dispersion analysis was carried out, in order to evaluate the safety against explosive atmosphere
Sense and sensitivity of double beta decay experiments
The search for neutrinoless double beta decay is a very active field in which
the number of proposals for next-generation experiments has proliferated. In
this paper we attempt to address both the sense and the sensitivity of such
proposals. Sensitivity comes first, by means of proposing a simple and
unambiguous statistical recipe to derive the sensitivity to a putative Majorana
neutrino mass, m_bb. In order to make sense of how the different experimental
approaches compare, we apply this recipe to a selection of proposals, comparing
the resulting sensitivities. We also propose a "physics-motivated range" (PMR)
of the nuclear matrix elements as a unifying criterium between the different
nuclear models. The expected performance of the proposals is parametrized in
terms of only four numbers: energy resolution, background rate (per unit time,
isotope mass and energy), detection efficiency, and bb isotope mass. For each
proposal, both a reference and an optimistic scenario for the experimental
performance are studied. In the reference scenario we find that all the
proposals will be able to partially explore the degenerate spectrum, without
fully covering it, although four of them (KamLAND-Zen, CUORE, NEXT and EXO)
will approach the 50 meV boundary. In the optimistic scenario, we find that
CUORE and the xenon-based proposals (KamLAND-Zen, EXO and NEXT) will explore a
significant fraction of the inverse hierarchy, with NEXT covering it almost
fully. For the long term future, we argue that Xe-based experiments may provide
the best case for a 1-ton scale experiment, given the potentially very low
backgrounds achievable and the expected scalability to large isotope masses.Comment: 30 pages, 12 figures, 6 table
Metachronous bladder metastases from renal cell carcinoma: a case report and review of the literature
INTRODUCTION: adrenal gland, parotid gland, pharynx, eye and bladder are rare localizations of metastases of renal cell carcinoma (RCC). We report a case of metachronous RCC metastases to the bladder in a patient with a medical history of transitional cell carcinoma (TCC) of the bladder. MATERIALS AND METHODS: a case study and review of the relevant literature are presented. RESULTS: during a follow-up cystoscopy examination following treatment of TCC, a single 5-mm lesion was detected and endoscopically resected. The histology of the resected sample was confirmed to be RCC, comparable to a primary kidney cancer and not recurrent TCC. CONCLUSION: the patient had a probability of metastases three years after nephrectomy of 62.9%. Survival rates following single metastasectomy are 60% and 38% at three and five years, respectively; metachronous diagnosis has a better prognosis than synchronous. During RCC follow-up, each lesion should be considered as a possible metastasis of RCC
Toroidal magnetized iron neutrino detector for a neutrino factory
A neutrino factory has unparalleled physics reach for the discovery and measurement of CP violation in the neutrino sector. A far detector for a neutrino factory must have good charge identification with excellent background rejection and a large mass. An elegant solution is to construct a magnetized iron neutrino detector (MIND) along the lines of MINOS, where iron plates provide a toroidal magnetic field and scintillator planes provide 3D space points. In this paper, the current status of a simulation of a toroidal MIND for a neutrino factory is discussed in light of the recent measurements of large θ13. The response and performance using the 10 GeV neutrino factory configuration are presented. It is shown that this setup has equivalent δCP reach to a MIND with a dipole field and is sensitive to the discovery of CP violation over 85% of the values of δCP
The Golden Channel at a Neutrino Factory revisited: improved sensitivities from a Magnetised Iron Neutrino Detector
This paper describes the performance and sensitivity to neutrino mixing
parameters of a Magnetised Iron Neutrino Detector (MIND) at a Neutrino Factory
with a neutrino beam created from the decay of 10 GeV muons. Specifically, it
is concerned with the ability of such a detector to detect muons of the
opposite sign to those stored (wrong-sign muons) while suppressing
contamination of the signal from the interactions of other neutrino species in
the beam. A new more realistic simulation and analysis, which improves the
efficiency of this detector at low energies, has been developed using the GENIE
neutrino event generator and the GEANT4 simulation toolkit. Low energy neutrino
events down to 1 GeV were selected, while reducing backgrounds to the
level. Signal efficiency plateaus of ~60% for and ~70% for
events were achieved starting at ~5 GeV. Contamination from the
oscillation channel was studied for the first
time and was found to be at the level between 1% and 4%. Full response matrices
are supplied for all the signal and background channels from 1 GeV to 10 GeV.
The sensitivity of an experiment involving a MIND detector of 100 ktonnes at
2000 km from the Neutrino Factory is calculated for the case of . For this value of , the accuracy in the
measurement of the CP violating phase is estimated to be , depending on the value of ,
the CP coverage at is 85% and the mass hierarchy would be determined
with better than level for all values of
The NEXT experiment: A high pressure xenon gas TPC for neutrinoless double beta decay searches
Abstract Neutrinoless double beta decay (ββ0ν) is a hypothetical, very slow nuclear transition in which two neutrons undergo beta decay simultaneously and without the emission of neutrinos. The importance of this process goes beyond its intrinsic interest: an unambiguous observation would establish a Majorana nature for the neutrino and prove the violation of lepton number. NEXT is a new experiment to search for neutrinoless double beta decay using a radiopure high-pressure xenon gas TPC, filled with 100 kg of Xe enriched in Xe-136. NEXT will be the first large high-pressure gas TPC to use electroluminescence readout with SOFT (Separated, Optimized FuncTions) technology. The design consists in asymmetric TPC, with photomultipliers behind a transparent cathode and position-sensitive light pixels behind the anode. The experiment is approved to start data taking at the Laboratorio Subterráneo de Canfranc (LSC), Spain, in 2014
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