1,537 research outputs found

    Ebonex-Supported PtM Anode Catalysts for PEM Water Electrolysis

    Get PDF
    The work presents a research on the preparation of Pt-based bimetallic catalysts dispersed on commercial Magnelli phase titania (Ebonex@) by sol gel method and investigation of their activity toward the oxygen evolution reaction (OER) in polymer electrolyte membrane water electrolysis (PEMWE). The catalytic support is also used for preparation of a carbon-free gas diffusion layer (ET30) integrated in the oxygen electrode of the membrane electrode assembly (MEA). The performance characteristics of MEA with PtM/Ebonex on ET30 are investigated in a laboratory PEMWE and compared to those of MEA with commercial carbon-based GDL with the same anode catalyst. It is proven that the chemical nature and electron density of the second metal have an essential effect on the catalyst surface structure and properties, including the lattice parameter, particle size, and electronic surface state state which in turn, reflect on the electrochemical behavior and catalytic activity. The catalysts PtCr/Ebonex and PtMn/Ebonex having deficiency of electrons in the valent d-orbital do not form an alloy with Pt and have lower catalytic activity. In contrast, the metallic components in PtFe/Ebonex and PtCo/Ebonex form a solid solution which results in changes in the catalyst structure and surface electron state, leading to enhanced OER efficieny compared to pure Pt/Ebonex

    New, emerging and re-emerging fungal diseases on medicinal and aromatic plants in European domain

    Get PDF
    Plant diseases cause agricultural and economic loss and impact negatively on human and animal health through mycotoxins and allergens produced by them. They also have consequences for biodiversity conservation. The pathogens could be classified in five categories: new - detected within the last five years; emerging - have always been present in an area but have grown in importance over the years; re-emerging - have been previously controlled but are once more a major problem associated with chemical resistance or changes in management or cultivars; threatening - not reported or limited in distribution in Europe and chronic-spreading – known for longer than 20 years and causing increased concern. Diseases emerge or re-emerge due to changes in farming practices, development of new strains of the pathogen, climate change, introduction of the pathogen to new geographical locations, or introduction of more efficient pathogen vectors. During the last years emerging infectious diseases (EIDs) are of special concern to researchers. Among all pathogens fungi are responsible for the greatest damage to plants in both agricultural and natural ecosystems. They represent over 70 % of all plant pathogens and over 30 % of plant EIDs. Surveys on fungal diseases of medicinal and aromatic plants have been carried out in the framework of several research projects between Germany, Bulgaria, Lithuania and Poland in the last two decades. EIDs have been reported, either as novel pathogens or as familiar pathogens affecting new host species. The importance of the problem could be illustrated by such examples as some phytopathogenic fungi on Apiaceae and Lamiaceae hosts discussed in the present work

    A novel non-carbon gas diffusion layer for PEM water electrolysis anodes

    Get PDF
    The work presents a research on the development of novel gas diffusion layer (GDL) suitable for application in PEM water electrolysis. The traditionally used carbon-based GDL is replaced by GDL containing sub-stoichiometry Mаgneli phase titanium oxide. The newly developed GDE is integrated in a membrane electrode assembly (MEA) containing highly active Pt catalyst and proton conductive polymer electrolyte membrane. The MEA performance is characterized in a laboratory PEM electrolyser at standard operative conditions by cyclic voltammetry and steady state polarization techniques. It is found that the new layer ensures excellent electrical conductivity and has very good stability at high anodic potentials. The determined morphology factors of the platinum catalyst however, show that further optimization of the porosity is required in order to improve the water transport to the reactive zone and the catalyst utilization

    Single-arm trials supporting the approval of anticancer medicinal products in the European Union: contextualization of trial results and observed clinical benefit

    Get PDF
    Background: Single-arm trials (SATs) can sometimes be used to support marketing authorization of anticancer medicinal products in the European Union. The level and durability of antitumor activity of the product as well as context are important aspects to determine the relevance of trial results. The aim of this study is to provide details on the contextualization of trial results and to evaluate the magnitude of benefit of medicinal products approved based on SATs. Materials and methods: We focused on anticancer medicinal products for solid tumors approved on the basis of SAT results (2012-2021). Data were retrieved from European public assessment reports and/or published literature. The benefit of these medicinal products was evaluated via the European Society for Medical Oncology (ESMO)-Magnitude of Clinical Benefit Scale (MCBS). Results: Eighteen medicinal products were approved based on 21 SATs—few medicinal products were supported by >1 SAT. For the majority of clinical trials, a clinically relevant treatment effect was (pre)specified (71.4%) and most often an accompanying sample size calculation was provided. For 10 studies, each testing a different medicinal product, a justification for the threshold for a clinically relevant treatment effect could be identified. At least 12 out of 18 applications included information to facilitate the contextualization of trial results, including six supportive studies. Of the pivotal SATs analyzed (n = 21), three were assigned an ESMO-MCBS score of 4, which corresponds to ‘substantial’ benefit. Conclusions: The clinical relevance of the treatment effects shown by medicinal products for solid tumors tested in SATs is dependent on the effect size and context. To better facilitate regulatory decision making, prespecifying and motivating a clinically relevant effect and aligning the sample size to that effect is important. External controls may facilitate in the contextualization process, but the associated limitations must be addressed

    Relative luminosity measurement of the LHC with the ATLAS forward calorimeter

    Full text link
    In this paper it is shown that a measurement of the relative luminosity changes at the LHC may be obtained by analysing the currents drawn from the high voltage power supplies of the electromagnetic section of the forward calorimeter of the ATLAS detector. The method was verified with a reproduction of a small section of the ATLAS forward calorimeter using proton beams of known beam energies and variable intensities at the U-70 accelerator at IHEP in Protvino, Russia. The experimental setup and the data taking during a test beam run in April 2008 are described in detail. A comparison of the measured high voltage currents with reference measurements from beam intensity monitors shows a linear dependence on the beam intensity. The non-linearities are measured to be less than 0.5 % combining statistical and systematic uncertainties.Comment: 16 page

    Improving mathematical learning in Scotland’s Curriculum for Excellence through problem posing:An integrative review

    Get PDF

    Search for R-parity Violating Supersymmetry in Dimuon and Four-Jets Channel

    Get PDF
    We present results of a search for R-parity-violating decay of the neutralino chi_1^0, taken to be the Lightest Supersymmetric Particle. It is assumed that this decay proceeds through one of the lepton-number violating couplings lambda-prime_2jk (j=1,2; k=1,2,3). This search is based on 77.5 pb-1 of data, collected by the D0 experiment at the Fermilab Tevatron in ppbar collisions at a center of mass energy of 1.8 TeV in 1992-1995.Comment: 10 pages, 3 figure

    Search for Electroweak Production of Single Top Quarks in ppbar Collisions

    Get PDF
    We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb.Comment: 11 pages, 2 figures. This is the published versio

    Probing BFKL Dynamics in the Dijet Cross Section at Large Rapidity Intervals in ppbar Collisions at sqrt{s}=1800 and 630 GeV

    Get PDF
    Inclusive dijet production at large pseudorapidity intervals (delta_eta) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large delta_eta in ppbar collisions at sqrt{s}=1800 and 630 GeV using the DO detector. The partonic cross section increases strongly with the size of delta_eta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of a_{BFKL}(20GeV)=1.65+/-0.07.Comment: Published in Physical Review Letter

    A Quasi-Model-Independent Search for New Physics at Large Transverse Momentum

    Get PDF
    We apply a quasi-model-independent strategy ("Sleuth") to search for new high p_T physics in approximately 100 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV collected by the DZero experiment during 1992-1996 at the Fermilab Tevatron. Over thirty-two e mu X, W+jets-like, Z+jets-like, and 3(lepton/photon)X exclusive final states are systematically analyzed for hints of physics beyond the standard model. Simultaneous sensitivity to a variety of models predicting new phenomena at the electroweak scale is demonstrated by testing the method on a particular signature in each set of final states. No evidence of new high p_T physics is observed in the course of this search, and we find that 89% of an ensemble of hypothetical similar experimental runs would have produced a final state with a candidate signal more interesting than the most interesting observed in these data.Comment: 28 pages, 17 figures. Submitted to Physical Review
    corecore