First Report on «Hop Stunt Viroid» (HSVd) from Some Mediterranean Countries

Hop stunt viroid (HSVd) has a very wide host range including most stone fruit trees. Among them, apricot is one of the most important host crops in the Mediterranean basin. In this study non-isotopic molecular hybridisation revealed, for the first time, the presence of HSVd on apricot in four Mediterranean countries (Cyprus, Greece, Morocco and Turkey). The results obtained by this technique were confirmed by northern-blot and RT-PCR analyses. The data presented in this work indicate a wider geographical distribution of this viroid than hitherto known and emphasise the need for this kind of study as part of the control effort

New corrosion inhibitors for copper in 3% NaCl solutions

The influence of azole derivatives on the corrosion of copper in 3% NaCl has been examined through steady-state and weight- loss measurements. Also the impact of the temperature on the efficiency of their action has been determined between 20 and 60 °C. The compounds acted as mixed inhibitors. In the anodic range they acted by building on the copper surface a passive film, more evident with a patented inhibitor (BITA) and diaminotriazole. In the presence of the latter compound, impedance measurements showed a thick film formation, confirmed by EDAX analysis

Contamination en métaux traces des sédiments du lac Fouarat (Maroc)

Résumé Les agglomérations urbaines de la ville de Kénitra sont susceptibles de perturber l\'équilibre écologique du lac Fouarat, à cause de leur essor démographique et industriel. Les sédiments du lac Fouarat ont été prélevés et analysés dans le but de déterminer leurs principales caractéristiques. La teneur en métaux et les paramètres chimiques ont été évalués dans la fraction inférieure à 63 μm. Les résultats obtenus montrent que les concentrations métalliques trouvées sont supérieures aux concentrations relevées par d\'autres travaux sur des témoins (non pollués). La comparaison entre les teneurs en métaux dans les sédiments du fond et ceux de surface d\'une carotte montre que les teneurs en zinc, en chrome et en cadmium diminuent de la surface vers la profondeur. L\'intensité de cette pollution est traduite par le facteur et l\'indice de contamination qui montrent une nette contamination de sédiments du lac Fouarat. Mots-clés : lac Fouarat, sédiments fins, métaux lourds, caractéristiques physicochimiques Abstract Metals trace contamination in lake Fouarat sediments (Morocco) Large agglomerations of Kénitra city may upset the equilibrium of Fouarat lake because of population and industrial growth. Sediments from Fouarat lake have been therefore analyzed to determine their main characteristics as well as their heavy metals Pollution. content; the latter has been evaluated in the fraction below 63 μm. The results obtained by the dosage of heavy metals show that sediments are loaded. These values are exceeding limits values noted in sediments non-polluted. The intensity of this pollution is reflected in the factor and evidence of contamination showing important metals contamination in the Fouarat lake. Key words: Fouarat lake, fine-grained sediments, heavy metals, physico-chemical caracteristics, Pollution. Afrique Science Vol.1(1) 2005: 109-12

Corrosion inhibition of a 70/30 cupronickel in a 3% NaCl medium by various azoles

The cathodic behaviour of a 70Cu-30Ni alloy in a 3% NaCl solution was studied by potential-current curves. It was shown that the corrosion current of the studied alloy increased with the rotation speed of the electrode

Influence des rejets des eaux usées sur la composition des eaux de surface et des sédiments superficiels du lac Merja Fouarate au Maroc

Résumé Le site objet du présent travail est un lac situé à proximité d'une grande agglomération urbaine. Cette dépression qui communique avec la nappe phréatique sousjacente est devenue actuellement un exutoire dans lequel sont déversés, sans aucun traitement préalable, les effluents domestiques et industriels des quartiers avoisinants. Dans le but d'évaluer l'influence des rejets déversés sur la qualité des eaux du site étudié, la composition des eaux de surface et des sédiments superficiels du lac en basses eaux, ainsi que celle des rejets s'y déversant, a été déterminée. L'évolution spatiotemporelle de quelques paramètres physico-chimiques a été suivie sur les eaux prélevées. Les résultats obtenus montrent que les eaux étudiées sont dures et assez chargées en sels dissous et en matière en suspension; elles présentent une minéralisation importante se rapprochant en général des valeurs limites indiquées par la directive de la CEE et la réglementation française et dépassant celles fixées par l'Organisation Mondiale de la Santé (OMS). Les eaux des rejets et des berges du lac ne sont pas conseillées à l'utilisation en irrigation. Les eaux superficielles du lac subissent l'influence néfaste des eaux usées de la ville de Kénitra. L'impact de cette pollution est plus ressenti au niveau des eaux et des sédiments superficiels des berges et s'étend même jusqu'à la zone centrale du lac. La nature des terrains avoisinants le lac contribue aussi à la dégradation de la qualité des eaux du lac, suite au lessivage en période de crue. Mots-clés : Lac Merja Fourate, pollution, eaux usées, composition chimique, eaux de surface, sédiments Abstract Influence of the worn water on the lake surface water and surface sediments com position of the lake Merja Fouarate in Morocco The site subject of this work is a lake located near an urban center. This depression which communicated with the subjacent ground water became currently a discharge site in which are poured domestic and industrial effluents without any preliminary treatments. The aim of this study is to evaluate the influence of the worn water on the lake water quality. In this way we have determined the lake surface water and the surface sediments composition. The obtained values have been compared to worn water case. The space-time evolution of some physicochemical parameters was monitored. The results obtained show that studied water is rather charged out of dissolved salt and suspended matter. They also show a hard water character, which presents in general bringing closer the limiting values indicated by the directive to the European Communities and the French regulation and exceeding that fixed by the World Health Organization. This leads that water of the rejections and the banks can not be used in the irrigation systems. The surface waters of the lake are subject to the harmful influence of wastewater of Kénitra town. The impact of this pollution is felt more on the level of water and surface sediments of the banks and extends even to the central zone of the lake. The nature of the soil contributes also by following scrubbing in a rainy and rising period. Key words: Lake Merja Fourate, pollution, wastewater, chemical composition, surface water, sediments Afrique Science Vol.1(1) 2005: 145-16

Corrosion inhibition of Armco iron in 1 M HCl solution by alkyltriazoles

The efficiency of N-decyl, N-undecyl and N-dodecyl-1,2,4-triazole compounds as corrosion inhibitors of Armco iron, has been studied. Using weight loss, and polarization data it has been shown that the N-dodecyl-1,2,4-triazole product was the best inhibitor, which acts on the hydrogen evolution reaction. Potentiodynamic polarization experiments showed that corrosion rate in presence and absence of N-dodecyl-1,2,4-triazole increases with increasing temperature from 30 to 60 °C. The corresponding activation energies were determined. The high inhibition efficiency was obtained at 50 °C in presence of 10-3 M of N-dodecyl-1,2,4-triazole. The effect of pH was examined from 0 to 3 values and the inhibiting effect decreases when pH value become higher than 2

Corrosion inhibition of copper in chloride solution by triazole derivatives

In this paper we examined the inhibition of copper corrosion in aerated neutral chloride solution. The inhibitors studied are azole types. The present paper is limited to the results of the anodic behavior of copper. Using current potential curves we have selected two compounds presenting the best inhibiting effect. The inhibiting action of these two species has been examined with quartz crystal microbalance (EQCM) and impedance measurements in 0.5M NaCl solution. These results were compared with those determined with bare copper electrode. In the case of blank solution it was show that copper corrosion product is forming spontaneusly and may protect against corrosion. At 0.5 mM inhibitors form an inhibiting film resulting from products adsorption on copper area. The inhibitors reduce considerably anodic current densities and lead to the copper passivation in a large anodic potential range

Détermination et spéciation chimique du plomb et du chrome dans les sédiments superficiels du Sebou, Maroc

Total concentration of lead and chromium and the spéciation of these metals in sediments of the River Sebou are studied to establish the extent to wich they are polluted and their capacity of remobilitation. Triacid attaque (HT-HNO3-HClO4) was used for the determination of total trace metal. The result show a highly polluted area (Cr, Pb) in the oued Fès area, for metal spéciation, a combination of two sequential schems was used (Tessier & al., 1979 ; Luoma & Bryan, 1979). From the results obtained, it can be concluded that Pb is mainly bonded to Fe-Mn hydroxides (in the lowest water period) and to the carbonate phase (in growing water period) and to the carbonate phase (in growing water period). Cr was also bonded to the hydroxide phase in the lowest water period, but in the growing water, this association caracterise only the riches sites (F, Rl, SI). In the other sections of the river, Cr was specially bonded to the residual phase.Des échantillons de sédiments superficiels prélevés le long du Sebou et dans ses affluents ont fait l'objet d'une étude par fractionnement chimique du chrome et du plomb. L'analyse du métal total met en exergue la forte contamination de l'oued Fès aussi bien en crue qu'en étiage. L'analyse par fractionnement chimique de ces deux métaux associée à un traitement statistique (SAS) montre que la distribution du plomb est contrôlée essentiellement par les sulfures et les silicates en période d'étiage, et par les carbonates en période de crue. La répartition du chrome est régie par les hydroxydes et la matière organique en étiage. En crue, le métal est surtout répartit sous la dépendance des hydroxydes. Ces types d'associations soulignent ainsi la grande mobilité du chrome par rapport au plomb.Azzaoui S., El Hanbali M., Leblanc Marc, El Boukhari A., Srhiri A. Détermination et spéciation chimique du plomb et du chrome dans les sédiments superficiels du Sebou, Maroc. In: Géologie Méditerranéenne. Tome 26, numéro 1-2, 1999. pp. 113-119

Effet des traitements thermiques sur la résistance à la corrosion en HCl molaire de l'alliage amorphe Fe-B-Si-C. Efficacité inhibitrice du diorthoaminophénoldisulfane (DOAPD)

Les thermogrammes d'analyse thermique différentielle (A.T.D.) et les spectres de diffraction de rayons X ont été réalisés avec l'alliage amorphe Fe-B-Si-C avant et après recuit. La résistance à la corrosion en HCl molaire de l'alliage recuit et non recuit a été évaluée et comparée à celle du fer cristallin αFe. L'efficacité inhibitrice de diorthoaminophenoldisulfane (DOAPD) a été calculée dans tous les cas

A new corrosion inhibitor for Cu60-Zn brass in 3% NaCl solution

The efficiency of 3-phenyl-1,2,4-triazole-5-thione (PTS) as brass corrosion inhibitor in 3% NaCl solution was investigated using electrochemical impedance spectroscopy gravimetric and potentiodynamic measurements. The surface were analyzed by scanning electron microscopy and energy dispersive x-ray analysis (EDAX).The results showed that the examined compound act as a mixed inhibitor. PTS inhibiting efficiency increased by augmenting its concentrations and by lengthening the testing time. At 1 mM concentration the polarization of the anodic branch at high current density is believed to be due to the resistance of the formed film. The EDAX analysis showed that the protection of brass by PTS is due to the formation of chemisorbed monolayer film. It growth involved precipitation of Cu and Zn ions may be as highly insoluble Cu-ZnPTS complexes at the solid/liquid interface