785 research outputs found
Cost-effectiveness of biologic treatment for rheumatoid arthritis in clinical practice: an achievable target?
Anti-TNF-α drugs: pharmacoeconomic analysis and proper use in pharmacological treatment in rheumatoid arthritis
Reducing the seismic vulnerability of cultural heritage buildings
European-Indian Economic Cross Cultural Programme - contract n.Âș ALA-95-23-2003-077-122
Dark Matter searches using gravitational wave bar detectors: quark nuggets and newtorites
Many experiments have searched for supersymmetric WIMP dark matter, with null
results. This may suggest to look for more exotic possibilities, for example
compact ultra-dense quark nuggets, widely discussed in literature with several
different names. Nuclearites are an example of candidate compact objects with
atomic size cross section. After a short discussion on nuclearites, the result
of a nuclearite search with the gravitational wave bar detectors Nautilus and
Explorer is reported. The geometrical acceptance of the bar detectors is 19.5
sr, that is smaller than that of other detectors used for similar
searches. However, the detection mechanism is completely different and is more
straightforward than in other detectors. The experimental limits we obtain are
of interest because, for nuclearites of mass less than g, we find a
flux smaller than that one predicted considering nuclearites as dark matter
candidates. Particles with gravitational only interactions (newtorites) are
another example. In this case the sensitivity is quite poor and a short
discussion is reported on possible improvements.Comment: published on Astroparticle Physics Sept 25th 2016 replaced fig 1
Quark nuggets search using 2350 Kg gravitational waves aluminum bar detectors
The gravitational wave resonant detectors can be used as detectors of quark
nuggets, like nuclearites (nuclear matter with a strange quark). This search
has been carried out using data from two 2350 Kg, 2 K cooled, aluminum bar
detectors: NAUTILUS, located in Frascati (Italy), and EXPLORER, that was
located in CERN Geneva (CH). Both antennas are equipped with cosmic ray shower
detectors: signals in the bar due to showers are continuously detected and used
to characterize the antenna performances. The bar excitation mechanism is based
on the so called thermo-acoustic effect, studied on dedicated experiments that
use particle beams. This mechanism predicts that vibrations of bars are induced
by the heat deposited in the bar from the particle. The geometrical acceptance
of the bar detectors is 19.5 sr, that is smaller than that of other
detectors used for similar searches. However, the detection mechanism is
completely different and is more straightforward than in other detectors. We
will show the results of ten years of data from NAUTILUS (2003-2012) and 7
years from EXPLORER (2003-2009). The experimental limits we obtain are of
interest because, for nuclearites of mass less than grams, we find a
flux smaller than that one predicted considering nuclearites as dark matter
candidates.Comment: presented to the 33rd International Cosmic Ray Conference Rio de
Janeiro 201
Piedmont and Aosta Valley inter-regional network in the context of the Italian National Network for rare diseases.
Analysis of 3 years of data from the gravitational wave detectors EXPLORER and NAUTILUS
We performed a search for short gravitational wave bursts using about 3 years
of data of the resonant bar detectors Nautilus and Explorer. Two types of
analysis were performed: a search for coincidences with a low background of
accidentals (0.1 over the entire period), and the calculation of upper limits
on the rate of gravitational wave bursts. Here we give a detailed account of
the methodology and we report the results: a null search for coincident events
and an upper limit that improves over all previous limits from resonant
antennas, and is competitive, in the range h_rss ~1E-19, with limits from
interferometric detectors. Some new methodological features are introduced that
have proven successful in the upper limits evaluation.Comment: 12 pages, 12 figure
Simplified indexes for the seismic assessment of masonry buildings : international database and validation
Heritage masonry buildings are particularly vulnerable to earthquakes because they are deteriorated and damaged, they were built with materials with low resistance, they are heavy and the connections between the various structural components are often insufficient. The present work details a simplified method of seismic assessment of large span masonry structures that was applied to a database of forty-four monuments in Italy, Portugal and Spain, providing lower bound formulas for different simplified geometrical indexes. Subsequently, the proposed thresholds are validated with data from the 2010-2011 Canterbury earthquakes, which includes forty-eight stone and clay brick masonry churches. Finally, fragility curves that can be used to estimate the damage as a function of the peak ground acceleration (PGA) are also provided
Experimental evaluation of a solid oxide fuel cell system exposed to inclinations and accelerations by ship motions
Solid Oxide Fuel Cell (SOFC) systems have the potential to reduce emissions from seagoing vessels. However, it is unknown whether ship motions influence the system's operation. In this research, a 1.5 kW SOFC module is operated on an inclination platform that emulates ship motions, to evaluate the influence of static and dynamic inclinations on the system's safety, operation, and lifetime. The test campaign consists of a static inclination test, a dynamic test, a degradation test, and a high acceleration test. There were no interruptions in the power supply during the different tests, and no detectable gas leakages or safety hazards. Although the SOFC does not fail in any test condition, dynamic inclinations result in forced oscillations in the fuel regulation, which propagate through the system by different feedback loops in the control architecture, leading to significant deviations in the operational parameters of the system. Additionally, for motion periods from 16 to 26 s, reoccurring exceedance of the fuel utilisation results in a gradual reduction of the power supply. Several enhancements are recommended to improve the design of SOFCs and marine fuel cell regulations to ensure their safe operation on ships.</p
Effect of cosmic rays on the resonant gravitational wave detector NAUTILUS at temperature T=1.5 K
The interaction between cosmic rays and the gravitational wave bar detector
NAUTILUS is experimentally studied with the aluminum bar at temperature of
T=1.5 K. The results are compared with those obtained in the previous runs when
the bar was at T=0.14 K. The results of the run at T = 1.5 K are in agreement
with the thermo-acoustic model; no large signals at unexpected rate are
noticed, unlike the data taken in the run at T = 0.14 K. The observations
suggest a larger efficiency in the mechanism of conversion of the particle
energy into vibrational mode energy when the aluminum bar is in the
superconductive status.Comment: 7 pages, 3 figures, 2 tables. Accepted by Physics Letters
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