24 research outputs found

    The Giant Radio Array for Neutrino Detection (GRAND) Project

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    The GRAND project aims to detect ultra-high-energy neutrinos, cosmic rays and gamma rays, with an array of 200,000 radio antennas over 200,000km2^2, split into ∼20 sub-arrays of ∼10,000km2^2 deployed worldwide. The strategy of GRAND is to detect air showers above 1017^{17}eV that are induced by the interaction of ultra-high-energy particles in the atmosphere or in the Earth crust, through its associated coherent radio-emission in the 50−200MHz range. In its final configuration, GRAND plans to reach a neutrino-sensitivity of ∼1010^{−10}GeV cm2^{−2}s1^{−1}sr1^{−1} above 5×1017^{17}eV combined with a sub-degree angular resolution. GRANDProto300, the 300-antenna pathfinder array, is planned to start data-taking in 2021. It aims at demonstrating autonomous radio detection of inclined air-showers, and study cosmic rays around the transition between Galactic and extra-Galactic sources. We present preliminary designs and simulation results, plans for the ongoing, staged approach to construction, and the rich research program made possible by the proposed sensitivity and angular resolution

    The Giant Radio Array for Neutrino Detection (GRAND) Project

    Get PDF
    The GRAND project aims to detect ultra-high-energy neutrinos, cosmic rays and gamma rays, with an array of 200,000 radio antennas over 200,000km2^2, split into ∼20 sub-arrays of ∼10,000km2^2 deployed worldwide. The strategy of GRAND is to detect air showers above 1017^{17}\,eV that are induced by the interaction of ultra-high-energy particles in the atmosphere or in the Earth crust, through its associated coherent radio-emission in the 50−200\,MHz range. In its final configuration, GRAND plans to reach a neutrino-sensitivity of ∼1010^{−10}GeVcm2^{−2}s1^{−1}sr1^{−1} above 5×1017^{17}\,eV combined with a sub-degree angular resolution. GRANDProto300, the 300-antenna pathfinder array, is planned to start data-taking in 2021. It aims at demonstrating autonomous radio detection of inclined air-showers, and study cosmic rays around the transition between Galactic and extra-Galactic sources. We present preliminary designs and simulation results, plans for the ongoing, staged approach to construction, and the rich research program made possible by the proposed sensitivity and angular resolution

    Self-trigger radio prototype array for GRAND

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    The GRANDProto300 (GP300) array is a pathfinder for the Giant Radio Array for Neutrino Detection (GRAND) project. The deployment of the array, consisting of 300 antennas, will start in 2021 in a radio-quiet area of ~200 km2 near Lenghu (~3000 m a.s.l.) in China. Serving as a test bench, the GP300 array is expected to pioneer techniques of autonomous radio detection including identification and reconstruction of nearly horizontal cosmic-ray (CR) air showers. In addition, the GP300 array is at a privileged position to study the transition between Galactic and extragalactic origins of cosmic rays, due to its large effective area and the precise measurements of both energy and mass composition for CRs with energies ranging from 30 PeV to 1 EeV. Using the GP300 array we will also investigate the potential sensitivity for radio transients such as Giant Radio Pulses and Fast Radio Bursts in the 50-200 MHz range

    Evaluating Goals And Impacts Of Two Metro Alternatives By The Ahp

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    The transport planning and its decision making involve a large number of goals and more than one alternative to be evaluated. This analysis comprises technical and financial features up to social and environmental impacts. We show how the AHP is a useful tool in this procedure, and evaluate several objectives and impacts of the implantation of the third metro line in the city of Sao Paulo, Brazil, where there were two alternative outlines and one of them to be selected.3012335Cohen, H.S., Stowers, J.R., (1978) Evaluating Urban Transportation System Alternatives, , Washington, System Design ConceptLassiere, A., (1976) The Environmental Evaluation of Transports Plans, , USA, Grow CopyrightLindau, L.A., Comparative Impact Study of Different Transportation Technology (1991) Revista Dos Transportes Públicos, 48, pp. 51-62Metro, R.J., (1989) "Technical-Economical-Financial Viability Study - Expansion Project of Rio de Janeiro's Metro", (in Portugese), , Rio de Janeiro, MetroMetro, S.P., (1980) "Technical-Economical-Financial Viability Study of the Third Metro Line of Sáb Paulo", (in Portuguese), , Sao Paulo, Metro e EMTUMetro, S.P., (1991) "Ambiental Impact Study", Lin Vila Madalena-Vila Prudente, (in Portuguese), , Sáo Paulo, MetroMouette, D., (1993) "The Utilization of the Analytic Hierarchy Process in Urban Transportation Planning and the Decision Making Process: An Analysis Turned to Ambiental Impacts", (in Portuguese), , M.Sc. Thesis, Sáo Paulo, Campinas, UNICAMPSaaty, T.L., A Scaling Method for Priorities in Hierarchical Structures (1977) Journal of Mathematical Psychology, 15, pp. 234-281Saaty, T.L., (1990) The Analytic Hierarchy Process, , Pittsburgh, USA, RWS PublicationsSaaty, T.L., How to Make a Decision: The Analytic Hierarchy Process (1990) European Journal of Operational Research, 48, pp. 9-26Saaty, T.L., (1990) The Analytic Hierarchy Process for Decisions in a Complex World, , USA, Pittsburgh: University of PittsburghVarma, A., "Environmental Considerations of Land Transport in Developing Countries", Part 1 (1992) Transport Reviews, 12 (2), pp. 101-11

    Transitions between technological generations of alternative fuel vehicles in Brazil

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    The transportation sector is responsible for nearly a quarter of greenhouse gases emissions (GHG); thus, incisive policies are necessary to mitigate the sector’s effect on climate change. Promoting alternative fuel vehicles (AFV) is an essential strategy to reduce GHG emissions in the short term. Here, we study the effects of governmental incentives on the diffusion of ethanol and flex-fuel vehicle technologies in Brazil. We use a multi-generation diffusion model which assumes that new technologies introduce fresh market potential for adopters as well as upgraders from established technologies. Our analysis indicates that tax rates affected the adoption of both gasoline and ethanol technology, but for flex vehicles, the effect of taxation is not significant. The effect of fuel price shocks during the 1990s meant that the introduction of ethanol technology made no significant impact on market potential and a negative word-of-mouth effect contributed to the technology’s failure. In contrast, the introduction of flex technology led to almost a doubling of total market potential. As policy suggestions, we emphasise the importance of tax reduction in addition to promoting versatile technologies, which insulate consumers against price fluctuations

    Assessment of greenhouse gases and pollutant emissions in the road freight transport sector: a case study for São Paulo state, Brazil

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    This study analyzes the road freight sector of São Paulo state to identify the best options to reduce greenhouse gases emissions and local pollutants, such as particulate matter, nitrogen oxides, carbon monoxide, and hydrocarbons. Additionally, the investment cost of each vehicle is also analyzed. Results show that electric options, including hybrid, battery, and hydrogen fuel-cell electric vehicles represent the best options to reduce pollutants and greenhouse gases emissions concomitantly, but considerable barriers for their deployment are still in place. With little long-term planning on the state level, electrification of the transport system, in combination with increased renewable electricity generation, would require considerable financial support to achieve the desired emissions reductions without increasing energy insecurity

    Local Observation and Spectroscopy of Optical Modes in Active Photonic Crystal Microcavity

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    We report the direct, room-temperature, near-field mapping and spectroscopy of the optical modes of a photonic-crystal microcavity containing quantum wells. We use a near-field optical probe to reveal the imprint of the cavity mode structure on the quantum-well emission. Furthermore, near-field spectroscopy allows us to demonstrate the strong spatial and spectral dependence of the coupling between the sources and the microcavity. This knowledge will be essential in devising future nanophotonic devices

    Equity issues and the PeCUS

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