Microscopic work function anisotropy and surface chemistry of 316L stainless steel using photoelectron emission microscopy

International audienceWe have studied the variation in the work function of the surface of sputtered cleaned 316L stainless steel with only a very thin residual oxide surface layer as a function of grain orientation using X-ray photo-electron emission microscopy (XPEEM) and Electron Backscattering Diffraction. The grains are mainly oriented [1 1 1] and [1 0 1]. Four distinct work function values spanning a 150 meV energy window are measured. Grains oriented [1 1 1] have a higher work function than those oriented [1 0 1]. From core level XPEEM we deduce that all grain surfaces are Cr enriched and Ni depleted whereas the Cr/Fe ratio is similar for all grains. The [1 1 1] oriented grains show evidence for a Cr 2 O 3 surface oxide and a higher concentration of defective oxygen sites

Tolérance d'une culture de froment à l'égard de l'hétérogeneite d'épandage des engrais azotés

Tolerance of wheat crop [Triticum aestivum] towards the spreading heterogeneity of nitrogen manure. The homogeneity of fertilizer application depends mainly on the regularity of transversal distribution. During the last few years, we have tested more than 300 distributors on farms. Results show big differences between the machines (CV between 5/ and more than 50/). The result is linked to distributor features, fertilizer characteristics and user skills. Moreover, crop yield is a function of fertilizer availability for plants. In the case of wheat, nitrogen is particularly important. Using farm application data, a simulation of wheat yield is built in relation with an increase of typical distribution mistakes. Thus, it is possible to assess an acceptable level of heterogeneity for the crop

Comparative study of response times of electronic and hydraulic flow controls in sprayers.

Depuis quelques année, certains pulvérisateurs agricoles sont équipés de systèmes électroniques de régulation des débits. Ceux-ci ont pour tâche d'adapter le débit de la rampe aux variations de la vitesse d'avancement du pulvérisateur ou à des modifications du débit de consigne. L'étude réalisée porte en premier lieu sur la comparaison du temps de réponse à des variations de la vitesse d'avancement de ces systèmes électroniques avec celui d'un dispositif hydraulique classique (ordonnateur de débit). D'autre part, la comparaison des temps de réponse de deux modèles existants est réalisée pour des variations de largeur de rampe (ouverture ou fermeture de sections de rampe) ou des modification volontaires de la quantité à épandre. Ces temps de réponse sont également convertis en surfaces traitées.Some of the sprayers that have been manufactured over the past few years are fitted with electronic flow control systems. The purpose of these devices is to adjust the flow rate to changes in the working speed or in the recommended spray volume. The first part of the study compares these electronic systems with one conventional hydraulic flow control (fow metering device) on the basis of their response time to variations in working speed. The study also compares the response time of two current types of electronic flow control systems at various boom widths (controlled by shutting off or opening parts of the boom) or to deliberate changes in the spray volume. Response times are also converted into equivalent treated areas

Structure and Conformation of (3s-asterisk,4s-asterisk,6r-asterisk)-3,6-dimethyl-4-phenylsulphonyltetrahydropyran-2-ones and (3r-asterisk,4r-asterisk,6r-asterisk)-3,6-dimethyl-4-phenylsulphonyltetrahydropyran-2-ones

The nucleophilic ring opening of propylene oxide by the lithio derivative of the trioxabicyclic orthoester 1 leads, after acidic treatment, to the title lactones 3a and 3b with no evidence of delta-lactones 3c and 3d. The stereochemistry of these two lactones has been established by X-ray diffraction analysis. The ring conformations observed in the solid phase are similar in both lactones and are compared with those observed in related molecules, However, the NMR spectroscopic analysis shows that this similarity does not exist in solution; lactone 3a adopts a different conformation

Spreading segregation of blended fertilizers : influence of particles properties

peer reviewe

Highly Effective and Green Catalytic Approach Toward -Dihydroxy-Telechelic Poly(trimethylene carbonate)

International audienc