Effects of Phenol Addition on Oil Extraction from Moroccan Oil Shale by Supercritical Toluene

In the present work, the effect of phenol on the supercritical extraction of the organic matter from Tarfaya's oil shale with toluene was evaluated. The experimental results showed clearly that phenol had a significant effect on the yield and the composition of the oils obtained. Moreover, it was shown that phenol was a very efficient modifier for oil shale, giving a good yield of recovery and a suitable maturation of the organic matter. The pitches prepared by mixing phenol and toluene contain more aromatics and have a high char yield at 950 °C compared to those obtained by extraction with supercritical toluene alone

Comparison of chemical and physical activation processes at obtaining adsorbents from moroccan oil shale

Within the Moroccan natural resources valorisation scheme, new adsorbents have been prepared from oil shale by chemical and physical activation processes. The activation process the authors have developed in this study give effective adsorbent materials. In view of the physico-chemical properties of these materials and application to the treatment of water loaded with a metal (Cr6+ ion) or organic (methylene blue (MB)) pollutant, it is concluded that the chemical activation process of oil shale at low temperature (250 °C) affords the best material. The material’s yield is good in comparison with the physical activation at the same temperature and the process is energy saving differently from that at 450 °C. Moreover, the chemical activation of oil shale with phosphoric acid at 250 °C produces a material with a good yield (about 70%), a high specific surface area (approximately 600 m2 /g) and a highly porous structure, which gives it a high retention of methylene blue and the Cr6+ ion

Simple scoring system to predict in-hospital mortality after surgery for infective endocarditis

BACKGROUND: Aspecific scoring systems are used to predict the risk of death postsurgery in patients with infective endocarditis (IE). The purpose of the present study was both to analyze the risk factors for in-hospital death, which complicates surgery for IE, and to create a mortality risk score based on the results of this analysis. METHODS AND RESULTS: Outcomes of 361 consecutive patients (mean age, 59.1\ub115.4 years) who had undergone surgery for IE in 8 European centers of cardiac surgery were recorded prospectively, and a risk factor analysis (multivariable logistic regression) for in-hospital death was performed. The discriminatory power of a new predictive scoring system was assessed with the receiver operating characteristic curve analysis. Score validation procedures were carried out. Fifty-six (15.5%) patients died postsurgery. BMI >27 kg/m2 (odds ratio [OR], 1.79; P=0.049), estimated glomerular filtration rate 55 mm Hg (OR, 1.78; P=0.032), and critical state (OR, 2.37; P=0.017) were independent predictors of in-hospital death. A scoring system was devised to predict in-hospital death postsurgery for IE (area under the receiver operating characteristic curve, 0.780; 95% CI, 0.734-0.822). The score performed better than 5 of 6 scoring systems for in-hospital death after cardiac surgery that were considered. CONCLUSIONS: A simple scoring system based on risk factors for in-hospital death was specifically created to predict mortality risk postsurgery in patients with IE

Confinement de la boue de lavage de phosphate dans l’argile de Safi sous forme de Céramiques de grandes diffusions

International audienc

Evaluer l’effet de l’ajout d’argile sur les transformations minéralogiques de la boue de lavage de phosphate

International audienc

Role of dispersant and humidity on the setting of millimetric films of aluminous cement prepared by tape casting

International audienceAn aluminous cement (Secar 71 from Lafarge) has been used for preparing millimetre thick films by tape casting. Slurry preparation is described. The effect of several dispersants has been studied. The optimum dispersion, associated with the minimum viscosity, is obtained with minimal amounts of dispersant in the case of acetic and propionic acids. Indeed, the corresponding quantities of dispersant are less than 0.5% by weight relative to cement. In addition to its dispersive role, acetic acid plays a role in the setting. It has a retarding effect below 1% by weight relative to the mass of cement and from this amount, it plays an accelerating role on setting. Tapes prepared with cement, water, acetic acid, PEG 300 have been left to set in different environments at 20 °C (50% or 95% relative humidity, water). The formation of aluminous calcium hydrates is most important when setting is done in water. Lastly, the advantage of setting in water is also discussed with respect to the elimination of the different organic products that have been used for tape castin

Effect of temperature and clay addition on the thermal behavior of phosphate sludge

The aim of the present work is to characterize the phosphate sludge from the area of Youssoufia (rich in CaO ~ 31%) and to study its thermal behavior alone and when mixed with clay from Safi (Morocco). This may contribute to its valorization as an alternative raw material for ceramic industries. The evolution of phases during the thermal treatment of phosphate sludge, clay and sludge–clay mixtures at different mass ratios (25 wt%, 50 wt%, and 75 wt%) was performed at different levels of temperatures from 600 to 1120 °C. Mineralogical analysis by X-ray diffraction (XRD) showed that the sludge mainly consisted of quartz, calcite, dolomite, and francolite. Dolomite and calcite vanished after sludge heating and two new phases were formed, namely akermanite and monticellite. For clay, it mainly consisted of illite, kaolinite, quartz, calcite, and dolomite. After clay sintering at high temperature, a new phase was formed, i.e. anorthite. The effects of the MO/SiO2 ratio (MO = CaO + MgO) in mixtures (clay + sludge) on the crystallization behavior of diopside and fluorapatite, and the disappearance of the akermanite were investigated. The results showed that the crystallization of diopside–fluorapatite increased when the MO/SiO2 ratio increased. Resumen: El objetivo del presente trabajo es caracterizar un lodo de fosfato del área de Youssoufia (rico en CaO ~ 31%) y estudiar su comportamiento térmico tras su mezcla con una arcilla de Safi (Marruecos). Este estudio puede contribuir a su valorización como materia prima alternativa para la industria cerámica. La evolución de las fases minerales durante el tratamiento térmico de lodos de fosfato, arcilla y mezclas de lodos y arcilla en diferentes proporciones de masa (25, 50 y 75% de peso) se realizó a diferentes temperaturas, desde 600 a 1.120 °C. El análisis por difracción de rayos X (DRX) permitió conocer la composición mineralógica del lodo formado principalmente por cuarzo, calcita, dolomita y francolita. La dolomita y la calcita desaparecieron tras el calentamiento del lodo y se formaron 2 nuevas fases, a saber, akermanita y monticellita. En cuanto a la arcilla, el análisis mineralógico evideció la presencia de illita, caolinita, cuarzo, calcita y dolomita como fases mayoritarias. Tras la descomposicón de la arcilla se formó anortita como fase de alta temperatura. Se investigaron los efectos de la relación MO/SiO2 (MO = CaO + MgO) en mezclas (arcilla + lodo) sobre la cristalización de diópsido y fluorapatita y la desaparición de la akermanita. Los resultados mostraron que la cristalización de diopsido-fluorapatita aumentó cuando creció el cociente MO/SiO2

Effet du dopage par le fer sur la synthèse de la ye’elimite

International audienc

Calcium aluminate cement tapes - Part II: Physical properties

International audienceTape casting is a process often used for the preparation of microelectronics substrates. The present work is a continuation of the first part where we have discussed the structural and microstructural characteristics of calcium aluminate cement tape. Indeed, in this second part, we focus on the physical properties of these tapes such as electrical, thermal, mechanical characterizations and surface roughness. We studied in particular how these physical properties vary according to the setting environment (water, air at 50% relative humidity or air saturated in humidity), setting time (1 day, 4 days or 1 month) and setting temperature (20 °C or 70 °C in the case of water setting environment). A Heat treatment on the consolidated tape was made essentially to decrease the dielectric constant. Following our results and comparing the physical properties with those of substrates commonly used in microelectronics, in particular alumina substrates, our films can be potentially used as microelectronics substrate