Energy efficiency improvement by the application of nanostructured coatings on axial piston pump slippers

Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when the pump (at low rotational speed or at partial displacement) works in the critical areas where the efficiency is low. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Due to the difficulty to reproduce the real working conditions of axial piston pump slippers, it has been made a hydraulic test bench properly designed in order to compare the performance of nano-coated slippers with respect to standard ones. The nano-coated and standard slippers have been subjected to the following working conditions: a test at variable pressure and constant rotational speed, a test at constant pressure and variable rotational speed. The comparison between standard and nanocoated slippers, for both working conditions, shows clearly that more than 20% of friction reduction can be achieved using the proposed nano-coating methodology

Geometrical vortex lattice pinning and melting in YBaCuO submicron bridges

Since the discovery of high-temperature superconductors (HTSs), most efforts of researchers have been focused on the fabrication of superconducting devices capable of immobilizing vortices, hence of operating at enhanced temperatures and magnetic fields. Recent findings that geometric restrictions may induce self-arresting hypervortices recovering the dissipation-free state at high fields and temperatures made superconducting strips a mainstream of superconductivity studies. Here we report on the geometrical melting of the vortex lattice in a wide YBCO submicron bridge preceded by magnetoresistance (MR) oscillations fingerprinting the underlying regular vortex structure. Combined magnetoresistance measurements and numerical simulations unambiguously relate the resistance oscillations to the penetration of vortex rows with intermediate geometrical pinning and uncover the details of geometrical melting. Our findings offer a reliable and reproducible pathway for controlling vortices in geometrically restricted nanodevices and introduce a novel technique of geometrical spectroscopy, inferring detailed information of the structure of the vortex system through a combined use of MR curves and large-scale simulations

Recognition of Morphometric Vertebral Fractures by Artificial Neural Networks: Analysis from GISMO Lombardia Database

BACKGROUND: It is known that bone mineral density (BMD) predicts the fracture's risk only partially and the severity and number of vertebral fractures are predictive of subsequent osteoporotic fractures (OF). Spinal deformity index (SDI) integrates the severity and number of morphometric vertebral fractures. Nowadays, there is interest in developing algorithms that use traditional statistics for predicting OF. Some studies suggest their poor sensitivity. Artificial Neural Networks (ANNs) could represent an alternative. So far, no study investigated ANNs ability in predicting OF and SDI. The aim of the present study is to compare ANNs and Logistic Regression (LR) in recognising, on the basis of osteoporotic risk-factors and other clinical information, patients with SDI≥1 and SDI≥5 from those with SDI = 0. METHODOLOGY: We compared ANNs prognostic performance with that of LR in identifying SDI≥1/SDI≥5 in 372 women with postmenopausal-osteoporosis (SDI≥1, n = 176; SDI = 0, n = 196; SDI≥5, n = 51), using 45 variables (44 clinical parameters plus BMD). ANNs were allowed to choose relevant input data automatically (TWIST-system-Semeion). Among 45 variables, 17 and 25 were selected by TWIST-system-Semeion, in SDI≥1 vs SDI = 0 (first) and SDI≥5 vs SDI = 0 (second) analysis. In the first analysis sensitivity of LR and ANNs was 35.8% and 72.5%, specificity 76.5% and 78.5% and accuracy 56.2% and 75.5%, respectively. In the second analysis, sensitivity of LR and ANNs was 37.3% and 74.8%, specificity 90.3% and 87.8%, and accuracy 63.8% and 81.3%, respectively. CONCLUSIONS: ANNs showed a better performance in identifying both SDI≥1 and SDI≥5, with a higher sensitivity, suggesting its promising role in the development of algorithm for predicting OF

KLOE results in kaon physics and prospects for KLOE-2

The phi-factory DAPHNE offers a possibility to select pure kaon beams, charged and neutral ones. In particular, neutral kaons from phi->KS KL are produced in pairs and the detection of a KS (KL) tags the presence of a KL (KS). This allows to perform precise measurements of kaon properties by means of KLOE detector. Another advantage of a phi-factory consists in fact that the neutral kaon pairs are produced in a pure quantum state (J^(PC) = 1^(--)), which allowsto investigate CP and CPT symmetries via quantum interference effects, as well as the basic principles of quantum mechanics.A review of the most recent results of the KLOE experiment at DAPHNE using pure kaon beams or via quantum interferometry is presented together with prospects for kaon physics at KLOE-2.Comment: 5 pages, 4 figures, From Phi To Psi 2011 conference, to be published in Nuclear Physics B (Proceedings Supplements

Search for heavy neutral lepton production in K+ decays

A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4| 2 and |Uμ4| 2 for heavy neutral lepton mass in the ranges 170–448 MeV/c2 and 250–373 MeV/c2, respectively. This improves on the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and above 300 MeV/c2 for |Uμ4|2

Review of Kaon Physics at CERN and in Europe

The Kaon physics program at CERN and in Europe will be presented. I will first give a short review of recent results form the NA48/2 and NA62 experiments, with special emphasis to the measurement of RK , the ratio of Kaon leptonic decays rates, K → eν and K → μν, using the full minimum bias data sample collected in 2007-2008. The main subject of the talk will be the study of the highly suppressed decay K → πνν. While its rate can be predicted with minimal theoretical uncertainty in the Standard Model (BR ∼ 8 × 10−11), the smallness of BR and the challenging experimental signature make it very difficult to measure. The branching ratio for this decay is thus a sensitive probe of the flavour sector of the SM. The aim of NA62 is the measurement of the K → πνν BR with ∼ 10% precision in two years of data taking. This will require the observation of 10K decays in the experiment's fiducial volume, as well as the use of high-performance systems for precision tracking, particle identification, and photon vetoing. These aspects of the experiment will also allow NA62 to carry out a rich program of searches for lepton flavour and/or number violating K decays. Data taking will start in October 2014. The physics prospects and the status of the construction and commissioning of the NA62 experiment will be presented. In the last part of the talk I will report on Kaon physics results and prospects from other experiments at CERN (e.g. LHCb) and in Europe (e.g. KLOE and KLOE-2) and briefly mention the status in US

Measurement of the very rare K+→π+ννˉK^+ \to \pi^+ \nu \bar\nu decay

The decay K+→π+νν¯ , with a very precisely predicted branching ratio of less than 10−10 , is among the best processes to reveal indirect effects of new physics. The NA62 experiment at CERN SPS is designed to study the K+→π+νν¯ decay and to measure its branching ratio using a decay-in-flight technique. NA62 took data in 2016, 2017 and 2018, reaching the sensitivity of the Standard Model for the K+→π+νν¯ decay by the analysis of the 2016 and 2017 data, and providing the most precise measurement of the branching ratio to date by the analysis of the 2018 data. This measurement is also used to set limits on BR(K+→π+X ), where X is a scalar or pseudo-scalar particle. The final result of the BR(K+→π+νν¯ ) measurement and its interpretation in terms of the K+→π+X decay from the analysis of the full 2016-2018 data set is presented, and future plans and prospects are reviewed

K+→π+ννˉK^+ \to \pi^+ \nu \bar \nu first NA62 results

The K+ → π+νν ̄ decay is characterised by a very precise prediction in the Standard Model (SM). Its branching ratio, which is expected to be less than 10−10 is one of the best candidates to indicate indirect effects of new physics beyond SM at the highest mass scales. The NA62 experiment at CERN SPS is designed to measure the branching ratio of the K+ → π+νν ̄ decay with an in-fight technique, never used before for this measurement. NA62 is taking data since in 2016 with the goal to reach the SM sensitivity, an accuracy of the order of 10%. In 2017 it has then collected 10 times more statistics and a similar amount of data is expected from the 2018 run. The preliminary result on K+ → π+νν ̄ from the full 2016 data set and prospects for future developments are presented

Physics beyond the standard model with kaons at NA62

Also a search for an invisible dark photon A′ has been performed, exploiting the efficient photon-veto capability and high resolution tracking of the NA62. The signal stems from the chain $\mathit{K}$+ → $\pi ^{+} \pi^{0}$ followed by $\pi^{0}$ → $\mathit{A}$′γ. No significant statistical excess has been identified. Upper limits on the dark photon coupling to the ordinary photon as a function of the dark photon mass have been set, improving on the previous limits over the mass range 60 - 110 MeV/c2