2,443 research outputs found

    CLASSICAL PROPERTIES AND SEMICLASSICAL CALCULATIONS IN A SPHERICAL NUCLEAR AVERAGE POTENTIAL

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    We study the relation between the classical properties of an average nuclear potential and its spectral properties. We have drawn the energy-action surface of this potential and related its properties to the spectral ones in the framework of the EBK semiclassical method. We also describe a method allowing us to get the evolution of the spectrum with the mass number

    Experimental and modeling study of the autoignition of 1-hexene/iso-octane mixtures at low temperatures

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    Autoignition delay times have been measured in a rapid compression machine at Lille at temperatures after compression from 630 to 840 K, pressures from 8 to 14 bar, \Phi = 1 and for a iso octane/1 hexene mixture containing 82% iso-octane and 18% 1 hexene. Results have shown that this mixture is strongly more reactive than pure iso-octane, but less reactive than pure 1 hexene. It exhibits a classical low temperature behaviour, with the appearance of cool flame and a negative temperature coefficient region. The composition of the reactive mixture obtained after the cool flame has also been determined. A detailed kinetic model has been obtained by using the system EXGAS, developed in Nancy for the automatic generation of kinetic mechanisms, and an acceptable agreement with the experimental results has been obtained both for autoignition delay times and for the distribution of products. A flow rate analysis reveals that the crossed reactions between species coming from both reactants (like H-abstractions or combinations) are negligible in the main flow consumption of the studied hydrocarbons. The ways of formation of the main primary products observed and the most sensitive rate constants have been identified

    Comparaison microstructurale et mécanique de polypropylènes-choc recyclés : suivi de l'endommagement et du vieillissement

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    International audienceCette étude porte sur des polypropylènes (PP)-chocs provenant du recyclage de pare-chocs de véhicules hors d'usage. Deux voies sont étudiées pour l'utilisation du matériau recyclé : soit en mélange avec du matériau neuf, soit après un traitement spécifique (TR) visant à éliminer la peinture. Des différences microstructurales ont été identifiées par DSC et DMA entre les différents PP-chocs étudiés. Ces matériaux soumis à des essais de traction s'endommagent par cavitation ; cet endommagement a été suivi et quantifié à différents stades de déformation à partir des mesures de variation de volume. Le matériau résultant du mélange présente une meilleure ductilité et un endommagement très légèrement retardé par rapport au matériau recyclé seul. Le traitement TR semble plus prometteur au niveau du comportement mécanique car il conduit à des matériaux encore plus ductiles et présentant un endommagement nettement retardé. Par ailleurs, le vieillissement thermique à 80°C de ces matériaux n'entraîne pas, après six à dix-huit mois de suivi, de variation significative au niveau des caractéristiques mécaniques et de l'endommagement, ce qui témoigne d'une très bonne stabilité de ces PP-chocs recyclés

    Supervision of the ATLAS High Level Trigger System

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    Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, PDF (from MS Word). PSN TUGT009; Available at http://www.slac.stanford.edu/econf/C0303241/proc/papers/TUGT009.PDF pers/THJT006.PDFInternational audienceThe ATLAS High Level Trigger (HLT) system provides software-based event selection after the initial LVL1 hardware trigger. It is composed of two stages, the LVL2 trigger and the Event Filter. The HLT is implemented as software tasks running on large processor farms. An essential part of the HLT is the supervision system, which is responsible for configuring, coordinating, controlling and monitoring the many hundreds of processes running in the HLT. A prototype implementation of the supervision system, using tools from the ATLAS Online Software system is presented. Results from scalability tests are also presented where the supervision system was shown to be capable of controlling over 1000 HLT processes running on 230 nodes

    The y activity from 11Li beta decay

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    The energies and absolute intensities of the γ-rays from the β-decay of 11Li are measured. There is no sizable β branch to the 11Be ground state. Only (5.2 ± 1.4) % of the β-decay strength does not lead to β-delayed particle emission. New β-delayed neutron branches to excited states of 10Be are observed and the total delayed neutron emission probability is deduced

    Surface modification of flax yarns by enzymatic treatment and their interfacial adhesion with thermoset matrices

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    The aim of this study was to assess the effects of commercially available and relatively inexpensive enzyme preparations based on endo 1,4-β-xylanase, pectinase and xyloglucanase on the thermal (TGA), morphological (SEM), chemical (FT-IR) and mechanical (single yarn tensile tests) properties of flax yarns. The preparation based on pectinase and xyloglucanase provided the best results, resulting in the effective removal of hydrophilic components such as hemicellulose and pectin, the individualization of yarns and increased thermal stability at the expense of a reduction in mechanical properties, depending on the treatment parameters. Single yarn fragmentation tests pointed out an improved interfacial adhesion after enzymatic treatment, with reduced debonding length values of 18% for an epoxy matrix and up to 36% for a vinylester resin compared to untreated flax yarns

    Subconjunctival Injection of XG-102, a c-Jun N-Terminal Kinase Inhibitor Peptide, in the Treatment of Endotoxin-Induced Uveitis in Rats.

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    Abstract Purpose: XG-102, a TAT-coupled dextrogyre peptide inhibiting the c-Jun N-terminal kinase, was shown efficient in the treatment of experimental uveitis. Preclinical studies are now performed to determine optimal XG-102 dose and route of administration in endotoxin-induced uveitis (EIU) in rats with the purpose of clinical study design. METHODS: EIU was induced in Lewis rats by lipopolysaccharides (LPS) injection. XG-102 was administered at the time of LPS challenge by intravenous (IV; 3.2, 35 or 355 μg/injection), intravitreal (IVT; 0.08, 0.2 or 2.2 μg/eye), or subconjunctival (SCJ; 0.2, 1.8 or 22 μg/eye) routes. Controls received either the vehicle (saline) or dexamethasone phosphate injections. Efficacy was assessed by clinical scoring, infiltrating cells count, and expression of inflammatory mediators [inducible nitric oxide synthase (iNOS), cytokine-induced neutrophil chemoattractant-1 (CINC-1)]. The effect of XG-102 on phosphorylation of c-Jun was evaluated by Western blot. RESULTS: XG-102 demonstrated a dose-dependent anti-inflammatory effect in EIU after IV and SCJ administrations. Respective doses of 35 and 1.8 μg were efficient as compared with the vehicle-injected controls, but only the highest doses, respectively 355 and 22 μg, were as efficient as dexamethasone phosphate. After IVT injections, the anti-inflammatory effect of XG-102 was clinically evaluated similar to the corticoid's effect with all the tested doses. Regardless of the administration route, the lowest efficient doses of XG-102 significantly decreased the ration of phospho c-Jun/total c-Jun, reduced cells infiltration in the treated eyes, and significantly downregulated iNOS and CINC-1 expression in the retina. CONCLUSION: These results confirm that XG-102 peptide has potential for treating intraocular inflammation. SCJ injection appears as a good compromise to provide a therapeutic effect while limiting side effects

    Propofol requirement and EEG alpha band power during general anesthesia provide complementary views on preoperative cognitive decline

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    Background: Although cognitive decline (CD) is associated with increased post-operative morbidity and mortality, routinely screening patients remains difficult. The main objective of this prospective study is to use the EEG response to a Propofol-based general anesthesia (GA) to reveal CD. Methods: 42 patients with collected EEG and Propofol target concentration infusion (TCI) during GA had a preoperative cognitive assessment using MoCA. We evaluated the performance of three variables to detect CD (MoCA < 25 points): age, Propofol requirement to induce unconsciousness (TCI at SEF95: 8–13 Hz) and the frontal alpha band power (AP at SEF95: 8–13 Hz). Results: The 17 patients (40%) with CD were significantly older (p < 0.001), had lower TCI (p < 0.001), and AP (p < 0.001). We found using logistic models that TCI and AP were the best set of variables associated with CD (AUC: 0.89) and performed better than age (p < 0.05). Propofol TCI had a greater impact on CD probability compared to AP, although both were complementary in detecting CD. Conclusion: TCI and AP contribute additively to reveal patient with preoperative cognitive decline. Further research on post-operative cognitive trajectory are necessary to confirm the interest of intra operative variables in addition or as a substitute to cognitive evaluation

    The mediating role of innovation in the relationship between market orientation and university performance in Pakistan

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    Universities globally are going through a paradigm shift with a need to become more innovatively market-oriented to handle the issue of growing competition for funding, as well as attracting/retaining the international/local competent students and academicians. However, there appears to be a dearth of research on how such state of affairs could be addressed, particularly in the emerging economies like Pakistan. In the light of resource-based theory (RBT), as well as organizational-learning theory (OLT), literature suggests that market-orientation (MO) and innovation are to be the desirable unique resources, as well as the guiding philosophies, to enable universities for a more competitive performance. Hence, this study investigated how resources like marketorientation (MO), and innovation, can influence university performance (UP). The study also tested empirically the potential mediating effect of innovation on the MOUP relationship. In addition, how the dimensions of MO influenced the innovation and university performance (UP) were also tested empirically in the universities of Pakistan. Results of the PLS path modelling (with 369 respondents from the target public-sector universities) firstly confirmed significant effect of the “universal construct of MO” and two of its dimensions “the advising and mentoring, as well as the intelligencegeneration and response” on UP. However, one dimension of MO, which is the administration-leadership, was not significantly supported to directly influence the UP. Secondly, the study confirmed that there were significant direct effects of the “universal construct of MO”, as well as all of its dimensions, on innovation. Thirdly, the study also found that there was a significant effect of innovation on UP. Furthermore, the bootstrapping results found significant mediation of innovation between the MO-UP relationship. Hence, the results show that UP can be directly enhanced through MO and innovation. Even the use of innovation as a mediator can further strengthen the MO-UP relationship. Based on the findings, the study offers theoretical and practical implications, followed by its limitations and directions, for future research

    Modelization of flow electrification in a polymer melt

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    Flow electrification of polymer melts is an important side effect of polymer processing. The studies dealing with this phenomenon are seldom and most of the scientific work has been focused on flow electrification of aqueous and insulating Newtonian liquids. From that prior art it is well established that the flow electrification in Newtonian liquids is a consequence of the formation of an ionic double layer. Convection of this layer induces the electrification of the liquid at the outlet of the pipe. In those models, the key parameters governing the flow electrification are thus the intrinsic electrical properties of the polymer and the flow characteristics. In this work, we reconsider the assumptions made previously and we propose a new approach to modelise the flow electrification in the particular case of non-Newtonian polymer materials in laminar flow conditions. We establish that, a key parameter for the electrification quantification in the polymer melt is the shape of the velocity profile. Additionally, in some cases, we show that a slip velocity at the polymer/die wall interface must be considered to describe accurately the electrification. As a consequence, we deduce that the slip velocity at the interface can be calculated by measuring the electrification: this work gives an alternative manner to measure the slip velocity during polymer flow
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