Effect of water quality on the performance of the galena and blend flotation: case of Draa Sfar complex sulphide ore, Morocco.

To contribute to the process optimization project of MCG (Mining Company of Guemassa-Marrakech, Morocco), a study was carried out on the effect of water quality on the performance of galena and blend flotation, using recycling tailings dam water. Flotation tests were carried out on a galena and blend ore provided by the Mining Company of Guemassa-Marrakech, Morocco (MCG).The obtained results showed that the mixture between the two types of water (Clear and tailing dam waters) in Pb circuit provides a lead recovery (72, 70 %) with a good quality of the final concentrate and selectivity toward (Cu, Zn and Fe). In the case of Zn circuit, the tailing dam water gives a good Zn recovery compared to those obtained in the case of clear water (≈ 70 %), but a low quality of the final Zn concentrate (42 %) than in the case of clear water (48 %) and the mixture water (45%)

Morphological and chemical characterization of carob pulps collected from four moroccan regions

The present research is included in a strategy of conservation and management of genetic resources for Carob tree (Ceratonia Siliqua L.) in Morocco. It has as one of its objectives, the evaluation of the morphological and chemical characteristics of four Moroccan ecotypes of carob pulps. The study related to morphological characterization reveals that there was a significant difference between the four populations from Meknes, Fez, Khemisset and Marrakech collected in 2018 and 2019. The lipid profile of carob pulp extracts analyzed by GC-MS is constituted of fatty acids, hydrocarbons, non-oxygenated compounds, sterols and tocopherols. The concentration of these compounds varies according to the population and year of collection. According to the results, the fatty acid contents are relatively high in 2019 with the dominance of palmitic acid. Additionally, our study approved the dominance of 1-Hexacosene, Tetracosane, Heptadecane. 1-iodo Hexadecane, 1-chloro Octadecane and 1, 54-dibromo Tetrapentacontane. Furthermore, it is noted that Stigmasterol, gamma-Sitosterol, beta-Sitosterol, alpha-Tocospiro A, alpha-Tocospiro B and Vitamin E are present in the samples. Moreover, the hierarchical analysis based on the results of the morphological and chromatographic characterization of the four populations’ pulps identify three groups. The first group included populations P3 and P4 respectively from Marrakech and Khemisset. The second group presented by the population P1 from Meknes. The population P2 from Fez constituted the third group

Chilling requirements and dormancy evolution in grapevine buds.

Fluctuations in winter chilling availability impact bud dormancy and budburst. The objective of this work was to determine chilling requirements to induce and overcome endodormancy (dormancy controlled by chilling) of buds in different grape cultivars. "Chardonnay", "Merlot" and "Cabernet Sauvignon" shoots were collected in Veranópolis-RS vineyards in 2010, and submitted to a constant 3 °C temperature or daily cycles of 3/15 °C for 12/12h or 18/6h, until reaching 1120 chilling hours (CH, sum of hours with temperature ≤ 7.2 °C). Periodically, part of the samples in each treatment was transferred to 25 °C for budburst evaluation (green tip). Chilling requirements to induce and overcome endodormancy vary among cultivars, reaching a total of 136 CH for "Chardonnay", 298 CH for "Merlot" and 392 CH for "Cabernet Sauvignon". Of these, approximately 39, 53 and 91 CH are required for induction of endodormancy in the three cultivars, respectively. The thermal regimes tested (constant or alternating) do not influence the response pattern of each cultivar to cold, with 15 °C being inert in the CH accumulation process. In addition, time required to start budburst reduces with the increase in CH, at a rate of one day per 62 CH, without significant impacts on budburst uniformity. Index terms: Chilling hours; endodormancy; budburst; Vitis vinifera

Chondrosarcome myxoïde extra-osseux: à propos d’un cas et revue de la littérature

Le chondrosarcome primitif des tissus mous est beaucoup plus rare que son homonyme intra-osseux, le type myxoïde est une entité distincte sur le plan clinique, histologique, immuno-histo-chimique, cytogénétique et évolutif. Le but de cette étude est d'évaluer les caractéristiques de cette tumeur et de mettre en évidence sa difficulté diagnostique et thérapeutique. Cette étude rapporte un cas de chondrosarcome myxoïde extra-osseux atteignant les parties molles, il s'agit d'une femme âgée de 28 ans ayant une localisation au niveau de la face antéro-externe du tiers moyen de la cuisse gauche, la patiente a été explorée par une IRM. L'examen histologique a confirmé le diagnostic et la patiente a bénéficié d'une résection large complétée par une chimiothérapie adjuvante, et le suivi n'a déploré aucune récidive ni métastase. Le diagnostic des chondrosarcomes primitifs extra osseux est particulièrement histologique et leur traitement repose sur la résection chirurgicale large suivie d'une chimiothérapie adjuvante

Optimisation of biodegradation conditions for the treatment of olive mill wastewater

International audienceThe aim of the present paper was to optimise the conditions of aerobic treatment of olive mill wastewater. To do so, the waste was treated following the experimental optimal design methodology studying the set of factors susceptible to influence the treatment (pH, C/N ratio, aeration and temperature). The results of a first series of experiments showed a strong correlation between the reduction in the levels of polyphenols and three of the parameters studied, i.e. the C/N ratio, aeration and temperature. Optimised conditions led to a 94% drop in polyphenols. Then, for a finer study of the conditions, just two parameters were varied, the pH and the C/N ratio. The results showed that the conditions of pH modification (addition of lime or sodium hydroxide) and the C/N ratio (urea or ammonium nitrate) allowed the micro-biological activity to be very significantly improved. This led to polyphenol reductions of 51% and 76%

Influence of sintering temperature on the mechanical properties of cordierite synthesized from andalusite and talc

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Optimization of cadmium ions biosorption by fish scale from aqueous solutions using factorial design analysis and Monte Carlo simulation studies

International audienceThis work investigated cadmium ions biosorption on Fish scales (FS) of Sardina pilchardus. Different relevant parameters such as initial pH in the range 2.14-7.76, initial cadmium concentration from 35 to 150 mg L-1, and biosorbent dose in the range 50-300 mg L-1, were examined. The effect of these parameters on the cadmium removal was analyzed and optimized using full factorial design methodology and the analysis of variance. The kinetics were modelized for pseudo-second order and pseudo-first order models. Results showed that the pseudo-second order kinetic gave the best fit for equilibrium data. The biosorption isotherms were investigated for Freundlich and Langmuir models. Langmuir isotherm model gave the best fit and led to a maximum biosorption capacity of Cd(II) on FS of 52.08 mg g-1. The results indicated that FS of was effective in the removal of cadmium ions. Optimum Cd(II) removal of 88.2 % was calculated for pH 3, 75 mg L-1 of Cd(II) and 250 mg L-1 of FS. Monte Carlo simulation was used as relatively greener pathway to study the biosorption behavior of Cd(II) ions onto FS. It showed that the interaction Cd(II) - hydroxyapatite was more favored than Cd(II) - collagen

Thermal and mechanical properties of cordierite refractory ceramic produced from stevensite-rich clay, kaolin and alumina

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Influence of sintering temperature on the microstructural and mechanical properties of cordierite synthesized from andalusite and talc

International audienceCordierite-based ceramic has been synthesized by solid state process from andalusite and talc mixture sintered at 1300 and 1350 °C for 2 h. The phase, microstructural and thermal characterizations of the samples were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), dilatometric and thermal analysis (TG/DTA). Brazilian and three-point bending tests were performed to evaluate the mechanical properties. XRD results showed a significant improvement in the cordierite formation at 1350 °C, whereas the sintering at 1300 °C was insufficient. The SEM observation showed that the sample sintered at 1350 °C was relatively dense. As a result of this densification, the flexural and tensile strengths at 1300 °C (15.4±1.2 and 12.2±1.9 MPa, respectively) were significantly enhanced with increasing temperature to 1350 °C (32±4.2 and 18.3±3.6 MPa, respectively)

Sequential modeling to understand and predict differentiated flowering time responses to warming in apple tree in contrasting climatic regions

National audienceLong-term series of temperature and apple flowering date were set up for seven climate-contrasting locations in Western Europe. A statistical analysis and a sequential modeling approach has been used to understand how global warming impacted dormancy release and flowering time in recent past and will impact in the future. Selected models explained up to 90% of the flowering date variability in Europe. Both the statistical analysis and the modeling of flowering dates supported that flowering advances in European temperate climates were clearly linked to faster fulfillments of heat requirements due to marked spring warming since the end of the 1980s. Delays of dormancy release, linked to chill temperature declines, were likely to also occur especially in the French Mediterranean region, which can explain a stationarity of the flowering date series since the beginning of the 2010s. Predicted changes until the end of the 21st century in Mediterranean region would confirm both a stationarity of flowering time and increasing delays of dormancy release. In addition, historical series of temperature and flowering dates were set up for three mild climate locations (one in Northern Morocco and two in Southern Brazil). While a flowering advance and a spring warming were statistically supported in Morocco, both flowering date and temperature series have generally remained stationary in the Brazilian locations. Finally, differentiated responses of apple tree flowering time were highlighted at the world scale in relation with differentiated warming contexts. Moreover, both sequential models selected from European data and models selected from Moroccan or Brazilian data appeared inadequate to simulate the observed flowering dates in the Moroccan and Brazilian locations. This cast a doubt on the sequential modeling relevance to predict dormancy release and flowering changes in the future warming context of European regions