An approximate Riemann solver for second-moment closures

International audienc

An approximate Roe-type Riemann solver for a class of realizable second order closures

International audienceA realizable, objective second-moment turbulence closure, allowing for an entropy carac-terisation, is analyzed with respect to its convective subset. The distinct characteristic wave system of these equations in non-conservation form is exposed. An approximate solution to the associated one-dimensional Riemann problem is constructed making use of approximate jump conditions obtained by assuming a linear path across shock waves. A numerical integration method based on a new approximate Riemann solver (ux-di erence-splitting) is proposed for use in conjunction with either unstructured or structured grids. Test calculations of quasi one-dimensional ow cases demonstrate the feasibility of the current technique even where Euler-based approaches fail

Assessment of the susceptibility to pests and diseases of 36 apple cultivars in four low-input organic orchards in France

One of the keystones of the organic orchard is the cultivar choice as one element of pest and disease control. However, few exhaustive data sets concerning the cultivar susceptibility to pests and diseases are available for growers. In order to identify cultivars adapted to organic production methods, the susceptibility to scab, aphids and powdery mildew and the agronomic properties of 36 cultivars were assessed in four French sites under different pedo-climatic conditions. Different levels of susceptibility to scab were observed for 23 scab Vf-resistant and 13 other cultivars. In the North of France where Vf resistance is overcome, the Vf cultivars displayed different levels of scab severity. A high variability in the susceptibility to aphids was observed whereas susceptibility to powdery mildew varied less. The analysis of susceptibility properties, yield and fruit quality, fruit storability and tree behaviour permitted to identify a set of interesting cultivars according to the site

ANALISIS PENGARUH CAR, NIM, LDR DAN NPL TERHADAP PROFITABILITAS BANK DENGAN VARIABEL KONTROL FIRM SIZE (Studi Empiris pada Bank Umum Go Public Yang Terdaftar di Bursa Efek Indonesia Tahun 2013-2017)

The purpose of this study was to determine the effect of CAR, NIM, LDR and NPL on the profitability of a Go Public Commercial Bank with Size as kontrol variable. Profitability is proxied by ROA as a measure of the size of profit that produced. The sample in this study is a Go Public commercial bank that listed on the IDX (Indonesia Stock Exchange) during the period 2013-2017. The number of samples were 21 banks taken by purposive sampling method. The analytical method of this study uses multiple linear regression with the SPSS 25 program which has previously passed the classic assumption test. The results of this study indicate that CAR has a positive but not significant effect on ROA. NIM has a positive and significant effect on ROA. NPL has a negative and significant effect on ROA. LDR has a positive but not significant effect on ROA. While using size as a kontrol variable indicates that CAR has a positive and significant effect on ROA

Anisotropic super-attenuation of capillary waves on driven glass interfaces

Metrological AFM measurements are performed on the silica glass interfaces of photonic band-gap fibres and hollow capillaries. The freezing of attenuated out-of-equilibrium capillary waves during the drawing process is shown to result in a reduced surface roughness. The roughness attenuation with respect to the expected thermodynamical limit is determined to vary with the drawing stress following a power law. A striking anisotropic character of the height correlation is observed: glass surfaces thus retain a structural record of the direction of the flow to which the liquid was submitted

Agronomie Oasienne. Projet de Coopération Franco-Tunisien. Proposition d'un projet de Coopération technique : "Recherches pour le Développement de l'agriculture d'oasis dans le Sud Tunisien". Rapport de missions Synthèse et propositions

Ce document est le résultat des missions réalisées au cours du premier semestre 1991 dans le cadre du projet d'appui à la recherche sur l'agriculture d'oasis en Tunisie. Il regroupe deux dossiers : - Rapports de missions et - Synthèses et propositions. Dans la première partie du document, après une brève présentation du projet, 4 volets sont détaillés : - "Inventaire du patrimoine génétique Oasien", - "Protection des cultures", "Agronomie et Développement", et "Technologie post-récolte". La deuxième partie du rapport présente les moyens, la programmation ainsi que le suivi et évaluation du proje

Host pathogen interactions in relation to management of light leaf spot disease (caused by Pyrenopeziza brassicae) on Brassica species

Light leaf spot, caused by Pyrenopeziza brassicae, is currently the most damaging disease problem in oilseed rape in the UK. According to recent survey data, the severity of epidemics has increased progressively across the UK, with current yield losses of up to £160M per annum in England and more severe epidemics in Scotland. Light leaf spot is a polycyclic disease with primary inoculum consisting of air-borne ascospores produced on diseased debris from the previous cropping season. Splash-dispersed conidia produced on diseased leaves are the main component of the secondary inoculum. P. brassicae is also able to infect and cause considerable yield losses on vegetable brassicas, especially Brussels sprouts. There may be spread of light leaf spot among different brassica species. Since they have a wide host range, Pyrenopeziza brassicae populations are likely to have considerable genetic diversity and there is evidence suggesting population variations between different regions, which need further study. Available disease-management tools are not sufficient to provide adequate control of the disease. There is a need to identify new sources of resistance, which can be integrated with fungicide applications to achieve sustainable management of light leaf spot. Several major resistance genes and quantitative trait loci have been identified in previous studies, but rapid improvements in the understanding of molecular mechanisms underpinning B. napus – P. brassicae interactions can be expected through exploitation of novel genetic and genomic information for brassicas and extracellular fungal pathogens.Peer reviewe

Assessment of diseases susceptibility of peach cultivars in experimental plots and on-farm for organic and low-input systems. Baseline of French case studies

Despite a high turn-over of new peach cultivars, their suitability for organic and low-input systems remains unknown for most of them. Diseases susceptibility is an important criteria to consider since diseases control is a bottleneck to peach production in theses systems. Since 2001, 81 peach cultivars were assessed in 2 experimental sites and 7 on-farm plots

Nondestructive measurement of the roughness of the inner surface of hollow core-photonic bandgap fibers

We present optical and atomic force microscopy measurements of the roughness of the core wall surface within a hollow core photonic bandgap fiber (HC-PBGF) over the [3×10-2 µm-1 to 30 µm-1] spatial frequency range. A recently developed immersion optical profilometry technique with picometer-scale sensitivity was used to measure the roughness of air-glass surfaces inside the fiber at unprecedentedly low spatial frequencies, which are known to have the highest impact on HC-PBGF scattering loss and, thus, determine their loss limit. Optical access to the inner surface of the core was obtained by the selective filling of the cladding holes with index matching liquid using techniques borrowed from micro-fluidics. Both measurement techniques reveal ultralow roughness levels exhibiting a 1/f spectral power density dependency characteristic of frozen surface capillary waves over a broad spatial frequency range. However, a deviation from this behavior at low spatial frequencies was observed for the first time, to the best of our knowledge