A multicriteria analysis of the potential degradations of a photovoltaic module to assess its robustness

Photovoltaic (PV) modules in service undergo more or less severe degradation depending on their operating environments, ages and technologies. In this work, we investigated the coupled influence of the climatic conditions of operation and of the degree of deterioration of a PV module on its energy production. We considered four silicon PV modules characterized in standard test conditions. The PV conversion is modeled by a single diode model taking into account the presence of a fault. Matlab/Simulink software was used to calculate the energy supplied at a constant load for the PV module with and without defects. The ratio between the energy produced with fault and without fault allowed to quantify the percentage of loss. This loss was plotted according to the degrees of degradation of the short-circuit current Isc, the open-circuit voltage Voc, the series resistance Rs and the shunt resistance Rsh. It is shown that when irradiance is held constant, the energy loss is lower with increasing temperature for Isc and Rsh, and vice versa for Voc and Rs. While the temperature is kept constant, the energy loss is lower when the irradiance increases for Isc and Rsh, and inversely for Voc and Rs. A multicriteria analysis enabled to determine the most robust module among the four ones

RNA-Seq reveals large quantitative differences between the transcriptomes of outbreak and non-outbreak locusts

Outbreaks of locust populations repeatedly devastate economies and ecosystems in large parts of the world. The consequent behavioural shift from solitarious to gregarious and the concomitant changes in the locusts’ biology are of relevant scientific interest. Yet, research on the main locust species has not benefitted from recent advances in genomics. In this first RNA-Seq study on Schistocerca gregaria, we report two transcriptomes, including many novel genes, as well as differential gene expression results. In line with the large biological differences between solitarious and gregarious locusts, almost half of the transcripts are differentially expressed between their central nervous systems. Most of these transcripts are over-expressed in the gregarious locusts, suggesting positive correlations between the levels of activity at the population, individual, tissue and gene expression levels. We group these differentially expressed transcripts by gene function and highlight those that are most likely to be associated with locusts’ phase change either in a species-specific or general manner. Finally, we discuss our findings in the context of population-level and physiological events leading to gregariousness.M. Bakkali wishes to thank the Spanish Ministerio de Ciencia y Tecnología for the for the Ramón y Cajal fellowship and for the BFU2010-16438 grant that supported both this research and the FPI studentship to Rubén Martín Blázquez. We thank Mrs. Pernille Lavgesen for revision of the English language writing of this manuscript. We also thank the editor for the valuable comments on the manuscript

The behavioural and environmental bases of gregarization in the desert locust Schistocerca gregaria (Forskaal)

SIGLEAvailable from British Library Document Supply Centre-DSC:D192255 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Dopage et caractéri sat ion des couches minces d'oxyde de Zinc déposées par spray pyrolyse Ul trasonique

Dans ce travail, nous avons réalisé un dispositif de Spray Pyrolyse Ultrasonique, pour déposer des couches minces d’oxyde de zinc dopé Al. Nous avons classé deux séries : La première série: la source de dopage a été Le nitrate d'aluminium (Al (NO3)3) avec pourcentage varie entre 0% jusqu'à 8%. La deuxième série: la source de dopage a été Le chlorure d'aluminium (Al Cl3) avec pourcentage varie entre 0% jusqu'à 8%. Notons que, les autres paramètres sont fixés, tel que: la température et la concentration d’oxyde de zinc. L’objectif de ce travail est l’étude de l’effet de dopage sur les propriétés optiques, structurales et électriques des couches minces d’oxyde de zinc

Deposition and analysis of Zinc Oxide thin films elaborated using spray pyrolysis for photovoltaic applications

Undoped and doped (by Al and In) ZnO thin films were deposited via two types of spray pyrolysis technique, ultrasonic and pneumatic onto glass substrates, to investigate the effect of several factors on the structural, optical and electrical properties of ZnO thin films. In the first part, we have deposited set samples of ZnO thin films using ultrasonic spray pyrolysis process with various start solution molarities for undoped ZnO and various doping concentrations for Al and In doped ZnO films. In the second, ZnO thin films were deposited using pneumatic spray pyrolysis process with two deferent spray pressure (1 and 1,5 bar) and various substrate temperatures for each pressure; also ZnO films with various aluminium doping rates were prepared. As well as, All the ZnO thin films were analyzed by assorted techniques X-ray diffraction, X-ray Dispersive Spectroscopy (EDS), SEM, UV-Vis, Hall Effect, four and two probes technique. This study allowed us to get ZnO thin films with very important structural, optical and electrical properties, which are very promising in photovoltaic applications

The synthesis and characterization of sprayed ZnO thin films: As a function of solution molarity

International audienceIn the present paper, the structural, electrical and optical properties of zinc oxide thin films were studied as a function of solution molarity. The ZnO thin films were deposited on glass substrates via the ultrasonic spray technique at 350°C. Polycrystalline films with a hexagonal wurtzite structure with (100) and (002) preferential orientation corresponding to ZnO films were observed. The optimal values of the crystallite size of the ZnO films were observed with (002) plan in 0.4 and 0.5 mol/l of solution molarity. All films exhibit an average optical transparency about 85% , in the visible region. The shift of optical transmittance towards smaller wavelength can be showed by the decrease of band gap caused by the change of crystallite size in polycrystalline. The maximum electrical conductivity of ZnO films was found of 2.29 (Ω.cm)–1 with 0.075 mol/l of solution molarity