299 research outputs found
Towards the production of 50'000 tonnes of low-carbon steel sheet for the LHC superconducting dipole and quadrupole magnets
A total of 50'000 tonnes of low-carbon steel sheet has been ordered for the LHC main magnets. After three years of production, about 10'000 tonnes of steel sheet have been produced by Cockerill-Sambre Groupe Usinor. This paper gives a summary of the manufacturing process and improvements implemented as well as an overview of the difficulties encountered during this production. Preliminary statistics obtained for the mechanical and magnetic steel properties are presented
Size quantization of Dirac fermions in graphene constrictions
Quantum point contacts (QPCs) are cornerstones of mesoscopic physics and
central building blocks for quantum electronics. Although the Fermi wave-length
in high-quality bulk graphene can be tuned up to hundreds of nanometers, the
observation of quantum confinement of Dirac electrons in nanostructured
graphene systems has proven surprisingly challenging. Here we show ballistic
transport and quantized conductance of size-confined Dirac fermions in
lithographically-defined graphene constrictions. At high charge carrier
densities, the observed conductance agrees excellently with the Landauer theory
of ballistic transport without any adjustable parameter. Experimental data and
simulations for the evolution of the conductance with magnetic field
unambiguously confirm the identification of size quantization in the
constriction. Close to the charge neutrality point, bias voltage spectroscopy
reveals a renormalized Fermi velocity () in
our graphene constrictions. Moreover, at low carrier density transport
measurements allow probing the density of localized states at edges, thus
offering a unique handle on edge physics in graphene devices.Comment: 24 pages including 20 figures and 1 table. Corrected typos. To appear
in Nature Communication
TREX-DM: a low background Micromegas-based TPC for low-mass WIMP detection
Dark Matter experiments are recently focusing their detection techniques in
low-mass WIMPs, which requires the use of light elements and low energy
threshold. In this context, we describe the TREX-DM experiment, a low
background Micromegas-based TPC for low-mass WIMP detection. Its main goal is
the operation of an active detection mass 0.3 kg, with an energy
threshold below 0.4 keVee and fully built with previously selected radiopure
materials. This work describes the commissioning of the actual setup situated
in a laboratory on surface and the updates needed for a possible physics run at
the Canfranc Underground Laboratory (LSC) in 2016. A preliminary background
model of TREX-DM is also presented, based on a Geant4 simulation, the
simulation of the detector's response and two discrimination methods: a
conservative muon/electron and one based on a neutron source. Based on this
background model, TREX-DM could be competitive in the search for low-mass
WIMPs. In particular it could be sensitive, e.g., to the low-mass WIMP
interpretation of the DAMA/LIBRA and other hints in a conservative scenario.Comment: Proceedings of the XIV International Conference on Topics in
Astroparticle and Underground Physics (TAUP 2015), 7-11 September 2015,
Torino, Ital
Advancing in the analysis of materials in electr(on)ic equipment
Despite there is a great effort to support strategies for a circular economy of electr(on)ics as maintenance, repair, remanufacture and reuse, recycling keeps being the final ultimate stage reached by them. As the supply of materials has become a key issue for the economic and technology development, more information about the content of materials in electr(on)ics is in order. This is especially for printed circuit boards contained in the majority of electr(on)ics which have a great variety of materials with a significant economic value. This paper discusses two methodologies to quantify the material composition of these parts. The first methodology quantifies the material content using two algorithms to identify the typologies of electr(on)ics components, and the average material composition of some typologies of electr(on)ic components given by original manufacturers. The second methodology uses the Database of SEmiconductors (DoSE) which contains the full material composition of about 250 different electr(on)ic components of printed circuit boards. A case study based on the analysis of two models of battery management systems contained in the batteries of electric vehicles is developed to compare the material composition results obtained from the two methodologies. Although the analysis is limited to some electr(on)ic components, mainly the integrated circuit and capacitors, the results of the composition of the battery management system are given for a list of materials including aluminum, copper, iron, gold, lead, nickel and tantalum. For two of the most economically relevant materials, copper and gold, the results obtained by the two methodologies differ 2% for copper and 4% for gold. To advance towards more automatized and systematic methodologies to estimate the material composition of the battery management systems, there are some further developments needed: to increase datasets for other electr(on)ic components as connectors, and better quantification of the number of layers and finishing of the circuit boards as they are made of significant quantities of copper and gold
TREX-DM: a low background Micromegas-based TPC for low mass WIMP detection
Dark Matter experiments are recently focusing their detection techniques in
low-mass WIMPs, which requires the use of light elements and low energy
threshold. In this context, we present the TREX-DM experiment, a low background
Micromegas-based TPC for low-mass WIMP detection. Its main goal is the
operation of an active detection mass 0.300 kg, with an energy threshold
below 0.4 keVee and fully built with previously selected radiopure materials.
This article describes the actual setup, the first results of the comissioning
in Ar+2\%iCH at 1.2 bar and the future updates for a possible
physics run at the Canfranc Underground Laboratory in 2016. A first background
model is also presented, based on Geant4 simulations and a muon/electron
discrimination method. In a conservative scenario, TREX-DM could be sensitive
to DAMA/LIBRA and other hints of positive WIMPs signals, with some space for
improvement with a neutron/electron discrimination method or the use of other
light gases.Comment: Proceedings of the 7th Symposium on Large TPCs for Low-Energy Rare
Event Detectio
Effectiveness of a medication adherence management intervention in a community pharmacy setting: a cluster randomised controlled trial
BackgroundNon-adherence to medications continues to be a burden worldwide, with significant negative consequences. Community pharmacist interventions seem to be effective at improving medication adherence. However, more evidence is needed regarding their impact on disease-specific outcomes. The aim was to evaluate the impact of a community pharmacist-led adherence management intervention on adherence and clinical outcomes in patients with hypertension, asthma and chronic obstructive pulmonary disease (COPD).MethodsA 6-month cluster randomised controlled trial was conducted in Spanish community pharmacies. Patients suffering from hypertension, asthma and COPD were recruited. Patients in the intervention group received a medication adherence management intervention and the control group received usual care. The intervention was based on theoretical frameworks for changing patient behaviour. Medication adherence, disease-specific outcomes (Asthma Control Questionnaire (ACQ) scores, Clinical COPD Questionnaire (CCQ) scores and blood pressure levels) and disease control were evaluated. A multilevel regression model was used to analyse the data.ResultsNinety-eight pharmacies and 1186 patients were recruited, with 1038 patients completing the study. Patients receiving the intervention had an OR of 5.12 (95% CI 3.20 to 8.20, pConclusionsA community pharmacist-led medication adherence intervention was effective at improving medication adherence and clinical outcomes in patients suffering from hypertension, asthma and COPD. Future research should explore the implementation of these interventions in routine practice.Trial registration numberACTRN12618000410257
Micromegas for dark matter searches: CAST/IAXO & TREX-DM experiments
The most compelling candidates for Dark Matter to day are WIMPs and axions. The applicability of gasesous Time Projection Chambers (TPCs) with Micromesh Gas Structures (Micromegas) to the search of these particles is explored within this work. Both particles would produce an extremely low rate at very low energies in particle detectors. Micromegas detectors can provide both low background rates and low energy threshold, due to the high granularity, radiopurity and uniformity of the readout. Small (few cm wide) Micromegas detectors are used to image the ax ion-induced x-ray signal expected in the CERN Axion Solar Telescope (CAST) experiment. We show the background levels obtained in CAST and the prospects to further reduce them to the values required by the Internation Axion Observatory (IAXO). We also present TREX-DM. a scaled-up version of the Micromegas used in axion research, but this time dedicated to the low-mass WIMP detection. TREX-DM is a high-pressure Micromegas-based TPC designed to host a few hundreds of grams of light nuclei (argon or neon) with energy thresholds potentially at the level of 100 eV. The detector is described in detail, as well as the results of the commissioning and characterization phase on surface. Besides, the background model of TREX-DM is presented, along with the anticipated sensitivity of this search, which could go beyond current experimental limits
Cost-Utility Analysis of a Medication Adherence Management Service Alongside a Cluster Randomized Control Trial in Community Pharmacy.
Background: It is necessary to determine the cost utility of adherence interventions in chronic diseases due to humanistic and economic burden of non-adherence.
Purpose: To evaluate, alongside a cluster-randomized controlled trial, the cost-utility of a pharmacist-led medication adherence management service (MAMS) compared with usual care in community pharmacies.
Materials and Methods: The trial was conducted over six months. Patients with treatments for hypertension, asthma or chronic obstructive pulmonary disease (COPD) were included. Patients in the intervention group (IG) received a MAMS based on a brief complex intervention, whilst patients in the control group (CG) received usual care. The cost–utility analysis adopted a health system perspective. Costs related to medications, healthcare resources and adherence intervention were included. The effectiveness was estimated as quality-adjusted life years (QALYs), using a multiple imputation missing data model. The incremental cost–utility ratio (ICUR) was calculated on the total sample of patients.
Results: A total of 1186 patients were enrolled (IG: 633; CG: 553). The total intervention cost was estimated to be € 27.33 ± 0.43 per patient for six months. There was no statistically significant difference in total cost of medications and healthcare resources per patient between IG and CG. The values of EQ-5D-5L at 6 months were significantly higher in the IG [IG: 0.881 ± 0.005 vs CG: 0.833 ± 0.006; p = 0.000]. In the base case, the service was more expensive and more effective than usual care, resulting in an ICUR of € 1,494.82/QALY. In the complete case, the service resulted in an ICUR of € 2,086.30/QALY, positioned between the north-east and south-east quadrants of the cost–utility plane. Using a threshold value of € 20,000/QALY gained, there is a 99% probability that the intervention is cost-effective.
Conclusion: The medication adherence management service resulted in an improvement in the quality of life of the population with chronic disease, with similar costs compared to usual care. The service is cost-effective
ZnO Nanowires Synthesized by Vapor Phase Transport Deposition on Transparent Oxide Substrates
Zinc oxide nanowires have been synthesized without using metal catalyst seed layers on fluorine-doped tin oxide (FTO) substrates by a modified vapor phase transport deposition process using a double-tube reactor. The unique reactor configuration creates a Zn-rich vapor environment that facilitates formation and growth of zinc oxide nanoparticles and wires (20–80 nm in diameter, up to 6 μm in length, density <40 nm apart) at substrate temperatures down to 300°C. Electron microscopy and other characterization techniques show nanowires with distinct morphologies when grown under different conditions. The effect of reaction parameters including reaction time, temperature, and carrier gas flow rate on the size, morphology, crystalline structure, and density of ZnO nanowires has been investigated. The nanowires grown by this method have a diameter, length, and density appropriate for use in fabricating hybrid polymer/metal oxide nanostructure solar cells. For example, it is preferable to have nanowires no more than 40 nm apart to minimize exciton recombination in polymer solar cells
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