778 research outputs found

    Numerical modelling of the debonding between CFRP strips and concrete in shear tests under static loads using different approaches

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    The present paper deals with the finite element (FE) analysis of bond slip between concrete and carbon fiber reinforced polymer (CFRP) strips in a single pull-out test under static loads. The commercial software LS-DYNA is used to simulate the test set-up using a plastic damage material model and an elastic material model for the concrete prism and the unidirectional CFRP strip, respectively. The bond interface between the concrete and the CFRP strip is simulated following three different approaches using a perfect bond model, a cohesive bond model and contact algorithms based on recently developed proposed bond slip models. The numerical model is validated based on experimental test results available from literature. The debonding failure mode and the delamination loads of the CFRP strip are predicted. The numerical results show a good agreement with the experimental data using the cohesive bond model. The perfect bond model gives an overestimation of the delamination loads and of the damage distribution in the concrete prism

    Wireless flow-sensor to inspect spray rate controllers

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    In Belgium, the mandatory inspection of sprayers was already started up in 1996 and the 8th inspection cycle (2017-2018-2019) is currently running. The inspection of sprayers is performed by official and mobile teams ruled by two inspection authorities and the management is done by the Federal Ministry for Consumer Protection, Public Health and the Environment (FAVV). In the Flemish region the inspection is delegated to the Institute for Agricultural and Fisheries Research (ILVO). In the past decade the number of field crop sprayers equipped with a spray rate controller increased significantly. In the first inspection cycle (1996-1998), only 4.58% of the field crop sprayers were equipped with a spray rate controller in Flanders. In the 7th inspection cycle (2014-2016), this percentage increased significantly to 26.92%. As the original inspection method for spray rate controllers showed some lacks and was time consuming, ILVO developed a simple and reliable method to test rate controllers on field crop and orchard sprayers.In Belgium, the mandatory inspection of sprayers was already started up in 1996 and the 8th inspection cycle (2017-2018-2019) is currently running. The inspection of sprayers is performed by official and mobile teams ruled by two inspection authorities and the management is done by the Federal Ministry for Consumer Protection, Public Health and the Environment (FAVV). In the Flemish region the inspection is delegated to the Institute for Agricultural and Fisheries Research (ILVO). In the past decade the number of field crop sprayers equipped with a spray rate controller increased significantly. In the first inspection cycle (1996-1998), only 4.58% of the field crop sprayers were equipped with a spray rate controller in Flanders. In the 7th inspection cycle (2014-2016), this percentage increased significantly to 26.92%. As the original inspection method for spray rate controllers showed some lacks and was time consuming, ILVO developed a simple and reliable method to test rate controllers on field crop and orchard sprayers

    Mechanical and hydraulic properties of residual dolomite and wad

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    The properties of residual dolomite, sometimes termed wad, are variable and uncertain. It represents the insoluble residue after dissolution of dolomite and is commonly found in the Neoarchaean Malmani Subgroup of the Chuniespoort Group (South Africa). This study comprised triaxial tests, crumb tests, X-Ray diffraction and fluorescence spectroscopy, foundation indicators, stereo-microscope imagery and permeability testing of the represented formations outcropping in the northeastern portions of South Africa. Results concur that residual dolomite is not typically dispersive, has low density that can be below that of water, mostly grades in the silt fraction, has high plasticity indices with low to high liquid limits, and has hydraulic conductivities in the order of 1x10-6 m/s. This new knowledge database contributes to our understanding of the flow through these systems and to how ingress scenario subsidences and sinkholes can possibly occur.The South African Water Research Commissionhttp://www.gssa.org.zapm2020Geolog

    Measuring and modelling the energy cost of reconfiguration in sensor networks [forthcoming]

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    As Wireless Sensor Networks (WSN) must operate for long periods on a limited power budget, estimating the energy cost of software operations is critical. Contemporary reconfiguration approaches for WSN allow for software evolution at various granularities; from reflashing of a complete software image, through replacement of complete applications, to the reconfiguration of individual software components. This paper contributes a generic model for measuring and modelling the energy cost of reconfiguration in WSN. We validate that this model is accurate in the face of different hardware platforms, software stacks and software encapsulation approaches. We have embedded this model in the LooCI middleware, resulting in the first energy aware reconfigurable component model for sensor networks. We evaluate our approach using two real-world WSN applications and demonstrate that our model predicts the energy cost of reconfiguration with 93% accuracy. Using this model we demonstrate that selecting the most appropriate software modularisation approach is key to minimising energy consumption

    Solution of the relativistic Dirac-Hulthen problem

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    The one-particle three-dimensional Dirac equation with spherical symmetry is solved for the Hulthen potential. The s-wave relativistic energy spectrum and two-component spinor wavefunctions are obtained analytically. Conforming to the standard feature of the relativistic problem, the solution space splits into two distinct subspaces depending on the sign of a fundamental parameter in the problem. Unique and interesting properties of the energy spectrum are pointed out and illustrated graphically for several values of the physical parameters. The square integrable two-component wavefunctions are written in terms of the Jacobi polynomials. The nonrelativistic limit reproduces the well-known nonrelativistic energy spectrum and results in Schrodinger equation with a "generalized" three-parameter Hulthen potential, which is the sum of the original Hulthen potential and its square.Comment: 13 pages, 3 color figure

    EURRECA nutritional planning and dietary assessment software tool: NutPlan

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    Background/Objectives: 'NutPlan' is developed within the EURRECA Network of Excellence (EURopean micronutrient RECommendations Aligned (http://www.eurreca.org). It is a user-friendly software programme with multiple functions: individual and group nutrition planning, recipe calculation, creating food labels, diet planning and nutrient intake assessment. This paper describes the newly developed software and its features. Subjects/Methods: 'NutPlan' contains the following databases: foods, dish recipes, meals, menus, average menus and glossary. These databases enable diet planning and diet analysis by comparing foods, dishes, meals or menus with currently available nutritional recommendations accessible by a link to EURRECA tool Nutri-RecQuest to meet individual/group nutritional needs. The software is upgraded by inserting new items (for example, foods, dishes, meals) and for a connection to other software programmes, thus allowing more advanced calculations to be completed. Conclusion: 'NutPlan' might be the software of choice for individual and group diet planning. It is aimed particularly at Eastern European and West Balkan countries, which currently lack dietary software. It is envisaged for use by small and medium enterprises in the food industry, as well as by health professionals, researchers and policy makers, and can be recommended for educational purposes. Given its characteristics of being upgraded to include new country-specific food data/database, it can be recognized as an important tool in nutritional capacity development in the Central Eastern European and other regions. European Journal of Clinical Nutrition (2010) 64, S38-S42; doi:10.1038/ejcn.2010.5

    Revisiting susceptibility testing in MDR-TB by a standardized quantitative phenotypic assessment in a European multicentre study

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    Objectives Treatment outcome of MDR-TB is critically dependent on the proper use of second-line drugs as per the result of in vitro drug susceptibility testing (DST). We aimed to establish a standardized DST procedure based on quantitative determination of drug resistance and compared the results with those of genotypes associated with drug resistance. Methods The protocol, based on MGIT 960 and the TB eXiST software, was evaluated in nine European reference laboratories. Resistance detection at a screening drug concentration was followed by determination of resistance levels and estimation of the resistance proportion. Mutations in 14 gene regions were investigated using established techniques. Results A total of 139 Mycobacterium tuberculosis isolates from patients with MDR-TB and resistance beyond MDR-TB were tested for 13 antituberculous drugs: isoniazid, rifampicin, rifabutin, ethambutol, pyrazinamide, streptomycin, para-aminosalicylic acid, ethionamide, amikacin, capreomycin, ofloxacin, moxifloxacin and linezolid. Concordance between phenotypic and genotypic resistance was >80%, except for ethambutol. Time to results was short (median 10 days). High-level resistance, which precludes the therapeutic use of an antituberculous drug, was observed in 49% of the isolates. The finding of a low or intermediate resistance level in 16% and 35% of the isolates, respectively, may help in designing an efficient personalized regimen for the treatment of MDR-TB patients. Conclusions The automated DST procedure permits accurate and rapid quantitative resistance profiling of first- and second-line antituberculous drugs. Prospective validation is warranted to determine the impact on patient car

    A blended preconception lifestyle programme for couples undergoing IVF:lessons learned from a multicentre randomized controlled trial

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    Study question: What is the effect of a blended preconception lifestyle programme on reproductive and lifestyle outcomes of couples going through their first 12 months of IVF as compared to an attention control condition?Summery answer:This randomized controlled trial (RCT) was stopped prematurely because of the coronavirus disease 2019 (Covid-19) pandemic but the available data did not suggest that a blended preconception lifestyle programme could meaningfully affect time to ongoing pregnancy or other reproductive and lifestyle outcomes.What is know already:Increasing evidence shows associations between a healthy lifestyle and IVF success rates. Lifestyle programmes provided through a mobile phone application have yet to be evaluated by RCTs in couples undergoing IVF.Study design, size, duration:A multicentre RCT (1:1) was carried out. The RCT started in January 2019 and was prematurely stopped because of the Covid-19 pandemic, leading to a reduced sample size (211 couples initiating IVF) and change in primary outcome (cumulative ongoing pregnancy to time to ongoing pregnancy).Participants/materials, setting, methods:Heterosexual couples initiating IVF in five fertility clinics were randomized between an attention control arm and an intervention arm for 12 months. The attention control arm received treatment information by mobile phone in addition to standard care. The intervention arm received the blended preconception lifestyle (PreLiFe)-programme in addition to standard care. The PreLiFe-programme included a mobile application, offering tailored advice and skills training on diet, physical activity and mindfulness, in combination with motivational interviewing over the telephone. The primary outcome was 'time to ongoing pregnancy'. Secondary reproductive outcomes included the Core Outcome Measures for Infertility Trials and IVF discontinuation. Changes in the following secondary lifestyle outcomes over 3 and 6 months were studied in both partners: diet quality, fruit intake, vegetable intake, total moderate to vigorous physical activity, sedentary behaviour, emotional distress, quality of life, BMI, and waist circumference. Finally, in the intervention arm, acceptability of the programme was evaluated and actual use of the mobile application part of the programme was tracked. Analysis was according to intention to treat.Main results and the role of chance:A total of 211 couples were randomized (105 control arm, 106 intervention arm). The hazard ratio of the intervention for time to ongoing pregnancy was 0.94 (95% CI 0.63 to 1.4). Little to no effect on other reproductive or lifestyle outcomes was identified. Although acceptability of the programme was good (6/10), considerable proportions of men (38%) and 9% of women did not actively use all the modules of the mobile application (diet, physical activity, or mindfulness).Limitations, reasons for caution:The findings of this RCT should be considered exploratory, as the Covid-19 pandemic limited its power and the actual use of the mobile application was low.Wider implications of the findings:This is the first multicentre RCT evaluating the effect of a blended preconception lifestyle programme for women and their partners undergoing IVF on both reproductive and lifestyle outcomes. This exploratory RCT highlights the need for further studies into optimal intervention characteristics and actual use of preconception lifestyle programmes, as well as RCTs evaluating effectiveness.Study fonding/competing intrest(s):Supported by the Research foundation Flanders (Belgium) (FWO-TBM; reference: T005417N). No competing interests to declare.Trial registration number:ClinicalTrials.gov Identifier: NCT03790449TRIAL REGISTRATION DATE 31 December 2018DATE OF FIRST PATIENT'S ENROLMENT 2 January 201

    K2 Y F5 crystal symmetry determined by using rare-earth ions as paramagnetic probes

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    The electron paramagnetic resonance angular dependences for Gd3+ and Ce3+ centers in K2 Y F5 crystals show that the Y3+ site has monoclinic Ch symmetry in these crystals. This site symmetry is compatible with the crystal structure having the Pnam space group. From the zero-field splitting parameters of the Gd3+ center, it is deduced that the symmetry of the Y3+ sites is close to trigonal around the b axis, distorted by the overall orthorhombic symmetry of the crystal structure. This information is required for the identification of radiation-induced centers in this material, which shows favorable properties for applications as thermoluminescent dosimeter. © 2007 The American Physical Society
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