AgNa2Mo3O9AsO4

The title compound, silver disodium trimolybdenum(VI) nonaoxide arsenate, AgNa2Mo3O9AsO4, was prepared by a solid-state reaction at 808 K. The structure consists of an infinite (Mo3AsO13)n ribbon, parallel to the c axis, composed of AsO4 tetra­hedra and MoO6 octa­hedra sharing edges and corners. The Na and Ag ions partially occupy several independent close positions, with various occupancies, in the inter-ribbon space delimited by the one-dimensional framework. The composition was refined to Ag1.06(1)Na1.94(1)Mo3O9AsO4

Does Magnetic Field Change Water pH?

Salt-laden waters pose major problems in the hydraulic field. Scaling problems can be troublesome for sanitary, potable and irrigation water networks. Also, irrigation water salinity is a major concern for agriculture, affecting crop productivity and yield. To alleviate some of these problems, various physical processes are put to the test such as magnetic processes. A laboratory experiment was conducted at the Laboratory of Natural Water Treatment of Borj Cedria Tunisia, to study the effect of different magnetic treatments (M1=3300 Gauss, M2=2900 Gauss, M3=5000 Gauss and Electromagnetic Em=900 Gauss) under two flow rate (0.03 and 0.06 letter/second) and two temperature (18 and 24oC) on water characteristics in order to observe the variation in the pH of water. The application of all magnetic field treatment showed slightly an increase in the pH of treated water compared to untreated water

Eau et environnement

Cet ouvrage est le fruit d’une collaboration entre climatologues, hydrologues et biogéographes tunisiens et français, entretenant un dialogue d’une rive à l’autre de la Méditerranée. Son contenu privilégie le quantitatif, le chiffre, plus que le rêve cher à Bachelard. Les volumes d’eau en mètres cube, par dizaines ou par milliards, et les hauteurs d’eau, en millimètres ou en mètres, y sont plus présents que le rare, le précieux, le beau et le poétique. Eau et environnement met délibérément l’accent sur les anomalies plus que sur les régularités. Le trop pluvieux, le trop sec, le trop mal réparti, le trop érosif, le trop mal exploité, le trop mal utilisé… y sont déclinés à diverses échelles, du pays au bassin versant élémentaire, en passant par les régions où se révèlent les déséquilibres de la ressource et de son utilisation. Eau et environnement s’inscrit dans un temps précis, la fin du xxe siècle, et brosse un état des lieux propre à la Tunisie et à la France, avec une courte référence à l’Algérie. L’ambition de la communauté de chercheurs qui ont contribué à cet ouvrage est néanmoins d’élargir les visions sectorielles des questions de l’eau à des approches dites intégrées, globales ou systémiques, susceptibles de se décliner sur d’autres espaces. Flotte cet esquif au fil du grand courant des études dédiées à l’eau !This volume is the result of a collaboration between Tunisian and French climatologists, hydrologists and biogeographers who have engaged in a dialogue from one shore of the Mediterranean to the other. In terms of content it concentrates on quantitative data and figures rather than Bachelard’s cherished dream. Water volumes expressed in tens or thousands of cubic metres, and water levels, in millimetres or metres, feature more prominently than rare, precious, beautiful or poetic details. Eau et environnement deliberately focuses on anomalies more than regularities. Excessive rainfall, insufficient rainfall, where water is too unevenly distributed, where it is too erosive, where it is under exploited or where it is too inefficiently used... all this information is provided at different levels, from the country to the basic catchment area, including regions where imbalances in the supply and use of the resource are identified. Eau et environnement focuses on a specific period in time, the end of the 20th century, and presents the specific situation in Tunisia and France, along with a short reference to Algeria. The ambition of the community of researchers who contributed to this volume is, however, to widen perceptions within the sector on water-related issues to include so-called integrated, global or systemic approaches which might be rolled out in other areas. This vessel will certainly be carried along in the current of water-related research