13,400 research outputs found
"Discrepant hardenings" in cosmic ray spectra: a first estimate of the effects on secondary antiproton and diffuse gamma-ray yields
Recent data from CREAM seem to confirm early suggestions that primary cosmic
ray (CR) spectra at few TeV/nucleon are harder than in the 10-100 GeV range.
Also, helium and heavier nuclei spectra appear systematically harder than the
proton fluxes at corresponding energies. We note here that if the measurements
reflect intrinsic features in the interstellar fluxes (as opposed to local
effects) appreciable modifications are expected in the sub-TeV range for the
secondary yields, such as antiprotons and diffuse gamma-rays. Presently, the
ignorance on the origin of the features represents a systematic error in the
extraction of astrophysical parameters as well as for background estimates for
indirect dark matter searches. We find that the spectral modifications are
appreciable above 100 GeV, and can be responsible for ~30% effects for
antiprotons at energies close to 1 TeV or for gamma's at energies close to 300
GeV, compared to currently considered predictions based on simple extrapolation
of input fluxes from low energy data. Alternatively, if the feature originates
from local sources, uncorrelated spectral changes might show up in antiproton
and high-energy gamma-rays, with the latter ones likely dependent from the
line-of-sight.Comment: 6 pages, 3 figures. Clarifications and references added, conclusions
unchanged. Matches published versio
Accessible interactive digital signage for visually impaired
In this workshop we discuss the potential of cross-modal haptic-auditory feedback for empowering visually impaired people to experience Interactive Digital Signage
Evaluation of the infrared test method for the olympus thermal balance tests
The performance of the infrared (IR) rig used for the thermal balance testing of the Olympus S/C thermal model is discussed. Included in this evaluation are the rig effects themselves, the IRFLUX computer code used to predict the radiation inputs, the Monitored Background Radiometers (MBR's) developed to measure the absorbed radiation flux intensity, the Uniform Temperature Reference (UTR) based temperature measurement system and the data acquisition system. A preliminary set of verification tests were performed on a 1 m x 1 m zone to assess the performance of the IR lamps, calrods, MBR's and aluminized baffles. The results were used, in part, to obtain some empirical data required for the IRFLUX code. This data included lamp and calrod characteristics, the absorptance function for various surface types, and the baffle reflectivities
New results on source and diffusion spectral features of Galactic cosmic rays: I- B/C ratio
In a previous study (Maurin et al., 2001), we explored the set of parameters
describing diffusive propagation of cosmic rays (galactic convection,
reacceleration, halo thickness, spectral index and normalization of the
diffusion coefficient), and we identified those giving a good fit to the
measured B/C ratio. This study is now extended to take into account a sixth
free parameter, namely the spectral index of sources. We use an updated version
of our code where the reacceleration term comes from standard minimal
reacceleration models. The goal of this paper is to present a general view of
the evolution of the goodness of fit to B/C data with the propagation
parameters. In particular, we find that, unlike the well accepted picture, and
in accordance with our previous study, a Kolmogorov-like power spectrum for
diffusion is strongly disfavored. Rather, the analysis points towards
along with source spectra index . Two
distinct energy dependences are used for the source spectra: the usual
power-law in rigidity and a law modified at low energy, the second choice being
only slightly preferred. We also show that the results are not much affected by
a different choice for the diffusion scheme. Finally, we compare our findings
to recent works, using other propagation models. This study will be further
refined in a companion paper, focusing on the fluxes of cosmic ray nuclei.Comment: 32 pages, 13 figures, accepted in A&
LOW-COST 4D BIM MODELLING: A COMPARISON BETWEEN FREECAD AND COMMERCIAL SOFTWARE
Abstract. The paper aims to investigate the potential inherent in a FOSS (Free and Open Source Software) approach for the 4D BIM modelling using Freecad. In order to reach this goal it shows a comparison of Freecad features with those of commercial software, considering the evaluation of the effective application of this Open Source software in the professional environment, and highlighting the progress in the FOSS BIM area, that still represents an unexplored study field if compared to the vast publications related to BIM modelling that occurred in the last two decades. To this end, the study has been carried out on a singular case study, a steel canopy which has been designed for the urban renewal of a public space in Teramo. Despite its size, the canopy required the definition of complex details. Its structural system has addressed the study to compare Freecad with some software dedicated to steel structures or particularly suitable for the modelling of this specific structural typology: Tekla Structures and Sketchup. Starting from a concise historical reconstruction of the FOSS spread, the paper introduces a brief overview of the potential of Freecad in terms of BIM modelling - also proposing an operational modality to facilitate the drawing of BIM elements within the software - and finally reaching to the examination of three simulations which has been carried. This comparison can be useful to establish the current state of development of Freecad in the field of 4D BIM
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