Search results for "RADIATION"
showing 10 items of 5298 documents
Model, software and database for line-mixing effects in the ν3 and ν4 bands of CH4 and tests using laboratory and planetary measurements-I: N2(and ai…
2006
International audience; Absorption spectra of the infrared ν3 and ν4 bands of CH4 perturbed by N2 over large ranges of pressure and temperature have been measured in the laboratory. A theoretical approach accounting for line mixing is proposed to (successfully) model these experiments. It is similar to that of Pieroni et al. [J Chem Phys 1999;110:7717–32] and is based on state-to-state rotational cross-sections calculated with a semi-classical approach and a few empirical parameters. The latter, which enable switching from the state space to the line space, are deduced from a fit of a single room temperature spectrum of the ν3 band at 50 atm. The comparisons between numerous measured and ca…
Single Event Transients and Pulse Quenching Effects in Bandgap Reference Topologies for Space Applications
2016
An architectural performance comparison of bandgap voltage reference variants, designed in a $0.18~\mu \text {m}$ CMOS process, is performed with respect to single event transients. These are commonly induced in microelectronics in the space radiation environment. Heavy ion tests (Silicon, Krypton, Xenon) are used to explore the analog single-event transients and have revealed pulse quenching mechanisms in analogue circuits. The different topologies are compared, in terms of cross-section, pulse duration and pulse amplitude. The measured results, and the explanations behind the findings, reveal important guidelines for designing analog integrated circuits, which are intended for space appli…
A Dynamic Electrical Scheme for the optimal reconfiguration of PV modules under non-homogeneous solar irradiation
2012
This paper presents a strategy for the maximization of the output power of photovoltaic (PV) systems under non homogeneous solar irradiation by means of automatic reconfiguration of the PV arrays layout. The innovation of the proposed approach is the employment of a simple Dynamic Electrical Scheme (DES), allowing a large number of possible modules interconnection, to be installed between the PV generator and the inverter. The models of the PV generator and of the DES have been realized and simulated with Simulink (Dynamic System Simulation for MATLAB). The attained experimental results appear to be quite interesting in terms of the attainable benefit in power and thus energy terms. The lim…
Improved measurement of $^8$B solar neutrinos with $1.5 kt·y$ of Borexino exposure
2017
We report on an improved measurement of the $^8$B solar neutrino interaction rate with the Borexino experiment at the Laboratori Nazionali del Gran Sasso. Neutrinos are detected via their elastic scattering on electrons in a large volume of liquid scintillator. The measured rate of scattered electrons above 3 MeV of energy is $0.223\substack{+0.015 \\ -0.016}\,(stat)\,\substack{+0.006 \\ -0.006}\,(syst)$ cpd/100 t, which corresponds to an observed solar neutrino flux assuming no neutrino flavor conversion of $\Phi\substack{\rm ES \\ ^8\rm B}=2.57\substack{+0.17 \\ -0.18}(stat)\substack{+0.07\\ -0.07}(syst)\times$10$^6$ cm$^{-2}\,$s$^{-1}$. This measurement exploits the active volume of the …
Modelización de riesgos climáticos y sistemas de vigilancia y alerta en la Comunitat Valenciana
2013
El primer objetivo de esta Tesis está relacionado con el desarrollo e implementación de diferentes sistemas de vigilancia y alerta para el territorio de la Comunitat Valenciana: un sistema de predicción meteorológica en tiempo real basado en el modelo atmosférico de mesoescala Regional Atmospheric Modeling System (RAMS) y un sistema de previsión del Índice UV (UVI), basado en el modelo Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). Además, se propone una metodología que proporciona un entorno computacional adecuado para la administración y coordinación de los diferentes procesos implicados en ambos sistemas de vigilancia. La principal mejora de la predicción UVI es la utiliza…
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory
2017
We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to $80^\circ$ and energies in excess of 4 EeV ($4 \times 10^{18}$ eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional informa…
Application of Molecular Topology for the Prediction of Reaction Yields and Anti-Inflammatory Activity of Heterocyclic Amidine Derivatives
2011
Topological-mathematical models based on multiple linear regression analyses have been built to predict the reaction yields and the anti-inflammatory activity of a set of heterocylic amidine derivatives, synthesized under environmental friendly conditions, using microwave irradiation. Two models with three variables each were selected. The models were validated by cross-validation and randomization tests. The final outcome demonstrates a good agreement between the predicted and experimental results, confirming the robustness of the method. These models also enabled the screening of virtual libraries for new amidine derivatives predicted to show higher values of reaction yields and anti-infl…
Design and implementation of the AMIGA embedded system for data acquisition
2021
The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and admin-istrative staff in Malargtie. We are very grateful to the following agencies and organizations for financial support: Comision Nacional de Energla Atomica, Agencia Nacional de Promocion Cientffica y Tec-nologica (ANPCyT) , Consejo Nacional de Investigaciones Cientfficas y Tecnicas (CONICET) , Gobierno de la Provincia de Mendoza, Municipalidad de Malargtie, NDM Holdings and Valle Las Leilas, in gratitude for their continuing cooperation over land access, Argentina; the Australian Research Council; Conselho…
Calibration of the underground muon detector of the Pierre Auger Observatory
2021
To obtain direct measurements of the muon content of extensive air showers with energy above $10^{16.5}$ eV, the Pierre Auger Observatory is currently being equipped with an underground muon detector (UMD), consisting of 219 10 $\mathrm{m^2}$-modules, each segmented into 64 scintillators coupled to silicon photomultipliers (SiPMs). Direct access to the shower muon content allows for the study of both of the composition of primary cosmic rays and of high-energy hadronic interactions in the forward direction. As the muon density can vary between tens of muons per m$^2$ close to the intersection of the shower axis with the ground to much less than one per m$^2$ when far away, the necessary bro…
COX-2 expression in chondrosarcoma: A role for celecoxib treatment?
2010
Chondrosarcomas are resistant to conventional chemo- and radiotherapy. A subset of chondrosarcomas arises secondarily in the benign tumour syndromes enchondromatosis (EC) and multiple osteochondromas (MO), and prevention of tumour development would greatly improve prognosis. We therefore investigated the effect of selective COX-2 inhibition on chondrosarcoma growth. COX-2 expression was studied in central- and peripheral cartilaginous tumours. The effect of COX-2 inhibition was assessed in four high-grade chondrosarcoma cell lines using celecoxib and NS-398 treatment. COX-2 activity (prostaglandin E-2 (PGE(2)) ELISA) and cell viability were measured. The (prophylactic) effect of celecoxib o…