923 research outputs found

    Background level of heavy-metals soil concentrations in an industrial area of Basilicata Region (Southern Italy)

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    In the framework of Basilicata region air quality monitoring, we are investigating the industrial area of Melfi town. This area has been chosen as test site to evaluate the environmental impact of anthropic activities on a rather unpolluted agricultural area. In this paper we discuss the procedure to characterize the background level of heavy-metals soil concentrations. The topsoil bioavailable fraction of eight elements (Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) has been collected in two annual surveys (1993 and 1994) on a georeferenced grid, translated in GIS informative layer. Statistical analysis of spatial and temporal patterns is shown in detail

    Particle decay branching ratios for states of astrophysical importance in 19Ne

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    We have measured proton and alpha-particle branching ratios of excited states in 19Ne formed using the 19F(3He,t) reaction at a beam energy of 25 MeV. These ratios have a large impact on the astrophysical reaction rates of 15O(alpha,gamma), 18F(p,gamma) and 18F(p,alpha), which are of interest in understanding energy generation in x-ray bursts and in interpreting anticipated gamma-ray observations of novae. We detect decay protons and alpha-particles using a silicon detector array in coincidence with tritons measured in the focal plane detector of our Enge split-pole spectrograph. The silicon array consists of five strip detectors of the type used in the Louvain-Edinburgh Detector Array, subtending angles from 130 degrees to 165 degrees with approximately 14% lab efficiency. The correlation angular distributions give additional confidence in some prior spin-parity assignments that were based on gamma branchings. We measure Gamma_p/Gamma=0.387+-0.016 for the 665 keV proton resonance, which agrees well with the direct measurement of Bardayan et al.Comment: 5 pages, 2 figures, 3 tables. Prepared using RevTex 4 and BibTex. Further minor revisions, incl. fig. 1 font size increase, 1 table removal, and minor changes to the tex

    Background level of heavy-metals soil concentrations in an industrial area of Basilicata Region (Southern Italy)

    Get PDF
    In the framework of Basilicata region air quality monitoring, we are investigating the industrial area of Melfi town. This area has been chosen as test site to evaluate the environmental impact of anthropic activities on a rather unpolluted agricultural area. In this paper we discuss the procedure to characterize the background level of heavy-metals soil concentrations. The topsoil bioavailable fraction of eight elements (Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) has been collected in two annual surveys (1993 and 1994) on a georeferenced grid, translated in GIS informative layer. Statistical analysis of spatial and temporal patterns is shown in detail

    El emprendedor desde el enfoque de la psicología positiva

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    En el presente trabajo se pretende analizar la conexión entre la psicología positiva y el comportamiento emprendedor. Desde sus orígenes y hasta hace no tanto tiempo atrás, la psicología sólo se centraba en la patología, en la debilidad y en el sufrimiento. Actualmente, el acento se pone sobre el bienestar mental o la calidad de vida para que el ser humano pueda, además de vivir saludablemente, salir fortalecido ante las adversidades o crisis que puedan presentársele. Conceptos propios de la psicología positiva como son resiliencia, motivación o felicidad, son cualidades propias del emprendedor, el cual tiene una sensibilidad especial para detectar oportunidades, movilizar recursos, interconectar información o tener ideas innovadoras. En definitiva, para hallar oportunidades donde otros no las ven o convertir en hechos lo pensado. Tener espíritu emprendedor es hacer las cosas, levantarse con más fuerza cada vez que se cae y ser capaz de convivir con la incertidumbre manteniéndose optimista. Por consiguiente, el estudio del comportamiento y el éxito emprendedor no puede ser correctamente entendido si no se aborda desde la óptica de la psicología positiva.In this paper, we expect to analyse the relationship between Positive Psychology and entrepreneur behaviour. Originally and since no some much time ago, psychology only concentrated in the pathology, weakness and suffering. Nowadays the emphasis is on the mental welfare or quality of life, so that the human being could, in addition of living healthy, get stronger in adversity or crisis that could experience. Typical concepts of Positive Psychology as resilience, motivation and happiness, are qualities of the entrepreneur. The entrepreneur has an special feeling to detect opportunities, mobilize resources, link information or has innovative ideas. In short, to find opportunities where other people don´t see it or make thoughts real. Having entrepreneur´s nature is to do things, to get up with more strength when you have fallen and to be optimist living with uncertainty. Therefore, the study of entrepreneur´s behaviour and sucess can´t be understood if we don´t take the point of view of Positive Psychology

    Breakup of loosely bound nuclei as indirect method in nuclear astrophysics: 8B, 9C, 23Al

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    We discuss the use of one-nucleon breakup reactions of loosely bound nuclei at intermediate energies as an indirect method in nuclear astrophysics. These are peripheral processes, therefore we can extract asymptotic normalization coefficients (ANC) from which reaction rates of astrophysical interest can be inferred. To show the usefulness of the method, three different cases are discussed. In the first, existing experimental data for the breakup of 8B at energies from 30 to 1000 MeV/u and of 9C at 285 MeV/u on light through heavy targets are analyzed. Glauber model calculations in the eikonal approximation and in the optical limit using different effective interactions give consistent, though slightly different results, showing the limits of the precision of the method. The results lead to the astrophysical factor S_17(0)=18.7+/-1.9 eVb for the key reaction for solar neutrino production 7Be(p,\gamma)8B. It is consistent with the values from other indirect methods and most direct measurements, but one. Breakup reactions can be measured with radioactive beams as weak as a few particles per second, and therefore can be used for cases where no direct measurements or other indirect methods for nuclear astrophysics can be applied. We discuss a proposed use of the breakup of the proton drip line nucleus 23Al to obtain spectroscopic information and the stellar reaction rate for 22Mg(p,\gamma)23Al.Comment: 6 pages, 4 figures. Presented at the conference "Nuclear Physics for Astrophysics 2", Debrecen, Hungary, May 2005. Prepared for the Proceeding

    Neutron time-of-flight measurements of charged-particle energy loss in inertial confinement fusion plasmas

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    Neutron spectra from secondary ^{3}H(d,n)α reactions produced by an implosion of a deuterium-gas capsule at the National Ignition Facility have been measured with order-of-magnitude improvements in statistics and resolution over past experiments. These new data and their sensitivity to the energy loss of fast tritons emitted from thermal ^{2}H(d,p)^{3}H reactions enable the first statistically significant investigation of charged-particle stopping via the emitted neutron spectrum. Radiation-hydrodynamic simulations, constrained to match a number of observables from the implosion, were used to predict the neutron spectra while employing two different energy loss models. This analysis represents the first test of stopping models under inertial confinement fusion conditions, covering plasma temperatures of k_{B}T≈1-4  keV and particle densities of n≈(12-2)×10^{24}  cm^{-3}. Under these conditions, we find significant deviations of our data from a theory employing classical collisions whereas the theory including quantum diffraction agrees with our data

    Measurement of E2 Transitions in the Coulomb Dissociation of 8B

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    In an effort to understand the implications of Coulomb dissociation experiments for the determination of the 7Be(p,gamma)8B reaction rate, longitudinal momentum distributions of 7Be fragments produced in the Coulomb dissociation of 44 and 81 MeV/nucleon 8B beams on a Pb target were measured. These distributions are characterized by asymmetries interpreted as the result of interference between E1 and E2 transition amplitudes in the Coulomb breakup. At the lower beam energy, both the asymmetries and the measured cross sections are well reproduced by perturbation theory calculations, allowing a determination of the E2 strength.Comment: 8 pages, 3 figure

    Study on thrust force and torque sensor signals in drilling of Al/CFRP stacks for aeronautical applications

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    Abstract Multi-material stack products made of carbon fibre reinforce polymers (CFRP) and light-weight metal alloys, such as aluminium alloys, are becoming increasingly employed for aerospace applications. When composite laminates are stacked with metal alloy sheets, the drilling process becomes more complex due to the diverse properties of the stacked materials which involve different wear mechanisms and different drilling parameters. In this framework, the aim of this paper is to investigate the drilling process of Al/CFRP stacks for aeronautical applications through an experimental testing campaign under different drilling conditions. In order to study the thrust force and torque generated during the drilling process, a multiple sensor system is employed for data acquisition, and an advanced methodology for sensor signal processing in the time and frequency domain is developed
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