719 research outputs found

    Digestão de óleo lubrificante encapsulado em forno de microondas com radiação focalizada por adição de amostra ao reagente pré-aquecido.

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    FOCUSED-MICROWAVE-ASSISTED DIGESTION OF ENCAPSULATED LUBRICATING OILS: GRADUAL SAMPLEADDITION TO PRE-HEATED ACID. The applicability of the recently proposed procedure based on gradual sample addition tomicrowave-assisted pre-heated concentrated acid is limited by the sample viscosity. In this work, lubricating oil samples with high viscositywere encapsulated and manually added to the microwave-assisted pre-heated concentrated digestion mixture. The procedure was appliedfor determination of Al, Ca, Cr, Cu, Fe, Mg, Ni, P, Pb, Si, Sn, Sr, V, W, and Zn in lubricating oil by inductively coupled plasma opticalemission spectrometry (ICP OES). Determined and certified values for Ca, Mg, P, and Zn in lubricating oil were in agreement at a 95% confidence level

    New detectors for the kaon and hypernuclear experiments with KaoS at MAMI and with PANDA at GSI

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    The KaoS spectrometer at the Mainz Microtron MAMI, Germany, is perceived as the ideal candidate for a dedicated spectrometer in kaon and hypernuclei electroproduction. KaoS will be equipped with new read-out electronics, a completely new focal plane detector package consisting of scintillating fibres, and a new trigger system. First prototypes of the fibre detectors and the associated new front-end electronics are shown in this contribution. The Mainz hypernuclei research program will complement the hypernuclear experiments at the planned FAIR facility at GSI, Germany. At the proposed antiproton storage ring the spectroscopy of double Lambda hypernuclei is one of the four main topics which will be addressed by the PANDA Collaboration. The experiments require the operation of high purity germanium (HPGe) detectors in high magnetic fields (B= 1T) in the presence of a large hadronic background. The performance of high resolution Ge detectors in such an environment has been investigated.Comment: Presentation at International Symposium on the Development of Detectors for Particle, Astroparticle and Synchrotron Radiation Experiments, Stanford, Ca (SNIC06), 6 pages, LaTeX, 11 eps figure

    Hypernuclear spectroscopy with K^- at rest on 7^7Li, 9^9Be, 13^{13}C and 16^{16}O

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    The FINUDA experiment collected data to study the production of hypernuclei on different nuclear targets. The hypernucleus formation occurred through the strangeness-exchange reaction K^-_{stop} + \; ^AZ \rightarrow \; ^A_{\Lambda}Z + \pi^-. From the analysis of the momentum of the emerging π\pi^-, binding energies and formation probabilities of Λ7^7_{\Lambda}Li, Λ9^9_{\Lambda}Be, Λ13^{13}_{\Lambda}C and Λ16^{16}_{\Lambda}O have been measured and are here presented. The behavior of the formation probability as a function of the atomic mass number A is also discussed.Comment: Accepted for publication in PL

    First determination of the one-proton induced Non-Mesonic Weak Decay width of p-shell {\Lambda}-Hypernuclei

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    Previous studies of proton and neutron spectra from Non-Mesonic Weak Decay of eight Lambda-Hypernuclei (A = 5-16) have been revisited. New values of the ratio of the two-nucleon and the one-proton induced decay widths, Gamma_2N/Gamma_p, are obtained from single proton spectra, Gamma_2N/Gamma_p = 0.50 +/- 0.24, and from neutron and proton coincidence spectra, Gamma_2N/Gamma_p = 0.36 +/- 0.14stat +0.05sys -0.04sys , in full agreement with previously published ones. With these values, a method is developed to extract the one-proton induced decay width in units of the free Lambda decay width, Gamma_p/Gamma_Lambda, without resorting to Intra Nuclear Cascade models but by exploiting only experimental data, under the assumption of a linear dependence on A of the Final State Interaction contribution. This is the first systematic determination ever done and it agrees within the errors with recent theoretical calculations.Comment: 16 pages, 3 figures, 2 table

    Σp\Sigma^- p emission rates in KK^- absorptions at rest on 6^6Li, 7^7Li, 9^{9}Be, 13^{13}C and 16^{16}O

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    An experimental study of the KstopAΣpAK^-_{stop}A\rightarrow \Sigma^- p A' reaction on A=6A=^6Li, 7^7Li, 9^9Be, 13^{13}C and 16^{16}O pp-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the DAΦ\PhiNE ϕ\phi-factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of Quasi-Free absorptions by a (np)(np) pair embedded in the AA nucleus can be obtained from the study of the missing mass distributions.Comment: Version accepted by PR

    Critical Review of Theoretical Models for Anomalous Effects (Cold Fusion) in Deuterated Metals

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    We briefly summarize the reported anomalous effects in deuterated metals at ambient temperature, commonly known as "Cold Fusion" (CF), with an emphasis on important experiments as well as the theoretical basis for the opposition to interpreting them as cold fusion. Then we critically examine more than 25 theoretical models for CF, including unusual nuclear and exotic chemical hypotheses. We conclude that they do not explain the data.Comment: 51 pages, 4 Figure
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