Electron Optical Studies of Vanadium Compounds

After an introductory chapter on the theory of electron microscopy, which was the predominant technique used in this study, the work described in this thesis was divided into two parts, namely, the thermal decomposition of ammonium metavanadate and the use of vanadium pentoxide as a support for rhodium catalyst. The thermal decomposition of ammonium metavanadate, up to 40

Adsorption of uranium and thorium on new adsorbent prepared from Moroccan oil shale impregnated with phosphoric acid

Attention has been focused recently on the production of new adsorbents from Moroccan oil shale of Tarfaya (layer R3) by chemical activation with phosphoric acid and its application in wastewaters treatment. The optimal conditions for the preparation were searched and the tests of adsorption of uranium and thorium ions were affected. The best product was obtained by used of the ratio of activated agent/precursor equal 3 and activation of the mixture in air at 250°C during two hours after prepocessing at 120°C in air. Under these conditions the maximal adsorption capacity of methylene blue and specific area (SBET) of the new adsorbent were 526 mg/g and 630 m2/g, respectively. A batch mode experiment was used to explore the performances of this adsorbent for the removal of the U and Th from aqueous solutions prepared from UO2(NO3)2.6H2O and Th(NO3)4.5H2O. The adsorption parameters for the two radioelements were determined by application of the Langmuir, Freundlich and Elovich models

Exchange reactions at calcium phosphates surface and applications to biomaterials

The interaction of calcium phosphates with biological molecules under controlled conditions permits the formulation of meaningful conclusions concerning the driving forces. The uptake and release at the material-solution interface is the result of the various interactions between and within the system components which include the solid surface, the adsorbate, the solvent and other solutes present. The understanding of adsorption and desorption mechanisms with respect to active molecules can be exploited for the development of drug delivery applications

ICT Integration into Chemistry-Physics Classes In Middle Schools Through A Participatory Pilot Project Approach

AbstractInformation and Communication Technology (ICT) based education was examined, through an integrated project, to experimentally determine how such technology could influence the motivation and performance of students in science (Chemistry-Physics, Mathematics, and Life-Earth sciences) in Morocco. The experiment was deliberately run at middle school level (age 12-14) as it constitutes the best stage in student life to influence their choice for the field of study. Two schools were selected based on their location and environment; one in a semi-rural area of Ifrane, and the other in the large city of Fes. The present study focuses more on the physical sciences (Chemistry-Physics), as they are taught together by the same teacher and represent a structural template of what was carried out within the framework of the pilot project.The project was the first of its kind in Morocco since it permitted decent usage of ICT in classroom sittings and allowed integral participation of middle school teachers in the elaboration of ICT pedagogical teaching resources using Arabic as teaching language. Control (standard) and experimental (ICT-based) classes were both taught by the same teachers and all the experiments were carried out in close collaboration between the authors and the teachers, with assistance from ICT engineers and technicians.Quantitative evaluation of the experimental data based on general balanced 3-stage nested design, together with qualitative assessment show a positive impact on the performance and motivation of students as well as their teachers.The project established successful practice guidelines and has set a promising roadmap for extending it at a larger scale to the rest of the country.As expected, this project encountered obstacles and limitations. Lessons learnt as well as suggestions are presented in this paper

Adsorption on apatitic calcium phosphates for drug delivery: interaction with bisphosphonate molecules

Bisphosphonates (BPs) are well established as an important class of drugs for the treatment and prevention of several bone disorders including osteoporosis. This work investigated the interaction of two bisphosphonates, risedronate and tiludronate, with several apatitic supports, a well-crystallised hydroxyapatite (HA) and nanocrystalline apatites with varying maturation times, chemical composition and surface characteristics. The purpose was to fully understand the adsorption mechanism and desorption process, by the evaluation of the effect of several physicochemical parameters (temperature, pH and concentration of calcium and phosphate ions). Whatever the nature of the BP and the structure and composition of the apatite, the adsorption of such anti-resorptive agents can be well described as an ion exchange-reaction between phosphates species on the apatitic surface and BP molecules in solution. However, the parameters of adsorption can vary depending on the physicochemical conditions of the adsorption reaction. In addition, the structure and composition of the apatitic surface also influence the adsorption properties. Finally, BPs molecules are slowly released from apatitic supports, because most of the adsorbed molecules are irreversibly bound and not spontaneously released by dilution or simple washing. Moreover, similar to their adsorption, the release of bisphosphonates is strongly affected not only by the chemical properties of the molecule, but also by the chemical and structural characteristics of the apatitic substrates. The understanding of the adsorption and release processes provides fundamental tools for the development of drug delivery systems using apatite materials

Using demand side management to adapt to water scarcity and climate change in the Saïss basin, Morocco

The Saïss Sub-Basin surface waters are greatly reduced, and will be completely depleted within 25 years. Climate Change and Training workshops directly led to the formation of the Zoubiya cooperative by local farmers. Members pooled their resources to create a water reservoir and drip irrigation systems thereby increasing the adaptive capacity of the region in response to water shortages. Drip irrigation results in water savings of about fifty percent per unit of crop yield. This project worked with multiple stakeholders and focused on benefits for the most vulnerable and disadvantaged communities within project sites, such as contract herders and women

L'adaptation au changement climatique dans le bassin de Tensift au Maroc par une gestion améliorée du bassin versant et le paiement pour les services environnementaux - rapport final

Ce projet bénéficie d'une subvention du Centre de recherches pour le développement international (CRDI), Ottawa, Canada.Le défi que le présent projet de recherche a essayé de relever est de trouver des pistes pour repenser la GIRE dans un contexte du changement climatique, tout en prenant en considération le maintien de la production des biens et services environnementaux. Ceci ne pourra se réaliser qu’à travers des actions permettant de prendre en considération la donne climatique et les instruments basés sur le marché (e.g. le Paiement pour les Services Environnementaux (PSE)) dans les politiques de gestion de l’eau