2,192 research outputs found

    Improving domiciliary robotic services by integrating the ASTRO Robot in an AmI Infrastructure

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    This work describes the ECHORD Experiment ASTROMOBILE, a project aimed to design, develop and test a system for favourable independent living, improved quality of life and efficiency of care for senior citizens in domestic environments. The system, composed of a mobile robotic platform (called ASTRO) and an Ambient Intelligent Infrastructure that actively cooperated between them and with the end-user, was designed and implemented with a user-centred design approach, involving different stakeholders. The system was designed to deliver services to users, like drug delivery, stand support, reminding, info-entertainment. The design took advantages of the integration of robotic platforms with smart environments, to provide to users higher quality and localization based services. Senior end-users were involved in the experimentation of the system in the DomoCasa Living Lab and feedbacks were gathered for the technology assessment. Particularly, this paper demonstrates the general feasibility of the ASTROMOBILE system and thanks to users feedbacks its acceptability and usability

    Averages of b-hadron Properties at the End of 2005

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    This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of at the end of 2005. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B meson decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries

    Designing cascades of electron transfer processes in multicomponent graphene conjugates

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    A novel family of nanocarbon-based materials was designed, synthesized, and probed within the context of charge-transfer cascades. We integrated electron-donating ferrocenes with light-harvesting/electron-donating (metallo)porphyrins and electron-accepting graphene nanoplates (GNP) into multicomponent conjugates. To control the rate of charge flow between the individual building blocks, we bridged them via oligo-p-phenyleneethynylenes of variable lengths by ÎČ-linkages and the Prato-Maggini reaction. With steady-state absorption, fluorescence, Raman, and XPS measurements we realized the basic physico-chemical characterization of the photo- and redox-active components and the multicomponent conjugates. Going beyond this, we performed transient absorption measurements and corroborated by single wavelength and target analyses that the selective (metallo)porphyrin photoexcitation triggers a cascade of charge transfer events, that is, charge separation, charge shift, and charge recombination, to enable the directed charge flow. The net result is a few nanosecond-lived charge-separated state featuring a GNP-delocalized electron and a one-electron oxidized ferrocenium

    Silicon nanoparticles as active materials for LED: laser synthesis and functionalization for tuning luminescence

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    Silicon nanocrystals (SiNPs) are an extensively studied light-emitting material due to their inherent biocompatibility and easy integration with silicon-based technology. Although low luminescence quantum yields of as-prepared SiNPs, the exploitation of the surface chemistry of SiNPs plays a key role in tuning their luminescence. In this work, the development of SiNPs as active materials for innovative LEDs was investigated. SiNPs were synthesized by using laser pyrolysis, a very flexible tool for lab-scale production in developmental quantities. The synthesized SiNPs have dimensions from 5 to 15 nm and high purity grade but show weak luminescence. For this reason, chemical treatments were performed on SiNPs: surface modifications lead to an improvement of their luminescence properties. Chemical and optical characterization were performed by conventional and advanced techniques, such as FTIR, BET, UV-VIS absorption and emission, XPS, TEM and confocal Raman. A Life Cycle Assessment (LCA) study of laser synthesis of SiNPs was conducted with the aim to identify the potential environmental impacts coming from this production method

    Averages of b-hadron properties at the end of 2006

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    This article reports the world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results at the end of 2006. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries.This article reports the world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results at the end of 2006. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries

    Inclusive Measure of |V_ub| with the Analytic Coupling Model

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    By analyzing B -> X_u l nu_l spectra with a model based on soft-gluon resummation and an analytic time-like QCD coupling, we obtain |V_ub| = (3.76 +-0.13 +- 0.22)*10^(-3), where the first and the second error refers to experimental and theoretical errors, respectively. The V_ub value is obtained from the available measured semileptonic branching fractions in limited regions of the phase-space. The distributions in the lepton energy E_l, the hadron invariant mass m_X, the light-cone momentum P_+ = E_X - p_X, together with the double distributions in (m_X,q^2) and (E_l,s_h^max), are used to select the phase-space regions. The q^2 is the dilepton squared momentum and s_h^max is the maximal m_X^2 at fixed q^2 and E_l. The V_ub value obtained is in complete agreement with the value coming from exclusive B decays and from an over-all fit to the Standard Model parameters. We show that the slight disagreement (up to +2 sigma) with respect to previous inclusive measurements is not related to different choices for the b (and c) masses but to a different modelling of the threshold (Sudakov) region.Comment: 19 pages, 2 figures, revised version accepted in Eur.Phys.J.

    Time-Dependent CP Asymmetries in B0 -> Ks pi0 gamma transitions

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    We report measurements of CP violation parameters in B0->Ks pi0 gamma transitions based on a data sample of 535x10^6 BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+ e- collider. One neutral B meson is fully reconstructed in the B0->Ks pi0 gamma mode. The flavor of the accompanying B meson is identified from its decay products. For a Ks pi0 invariant mass up to 1.8 GeV/c^2, we obtain S = -0.10 +- 0.31 +- 0.07 and A = -0.20 +- 0.20 +- 0.06. For a Ks pi0 invariant mass near the K*0(892) resonance, we obtain S = -0.32 +0.36-0.33 +-0.05 and A=-0.20 +-0.24 +-0.05.Comment: 6 pages, 3 figures, accepted by PR

    Measurement Of |V_ub| From Inclusive Charmless Semileptonic B Decays

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    We present the partial branching fraction for inclusive charmless semileptonic B decays and the corresponding value of the CKM matrix element |Vub|, using a multivariate analysis method to access ~90% of the B -> Xu l nu phase space. This approach dramatically reduces the theoretical uncertainties from the b-quark mass and non-perturbative QCD compared to all previous inclusive measurements. The results are based on a sample of 657 million B -Bbar pairs collected with the Belle detector. We find that Delta BR(B -> Xu l nu; p^*B_l>1.0 GeV/c=1.963 x (1 +/- 0.088(stat.) +/- 0.081(sys.)) x 10^-3. Corresponding values of |Vub| are extracted using several theoretical calculations.Comment: 9 pages, 1 figure, 2 tables. Published in PR

    Evidence for B0→χc1π0B^0 \to \chi_{c1} \pi ^0 at Belle

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    We present a measurement of the branching fraction for the Cabibbo- and color-suppressed B0→χc1π0B^0 \to \chi_{c1}\pi^0 decay based on a data sample of 657×106657\times 10^6 BBˉB\bar B events collected at the ΄(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e−e^+e^- collider. We observe a signal of 40±940\pm9 events with a significance of 4.7σ4.7\sigma including systematic uncertainties. The measured branching fraction is B(B0→χc1π0)=(1.12±0.25(stat.)±0.12(syst.))×10−5\mathcal {B}(B^0 \to \chi_{c1} \pi^0) = (1.12\pm 0.25(\rm {stat.})\pm 0.12({\rm syst.}))\times 10^{-5}.Comment: 5 pages, 5 figure
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