Manufacturing equivalent Clinker by indirect mechanosynthesis process

International audienceThis study is focused to the proposition of new cement manufacturing process. It is widely known that the cement production is responsible for a significant CO2 release each year (approximatively 4 billon ton). So, it is became necessary to find another cement manufacturing process with a minimum CO2 emission. The aim of this work is to manufacture equivalent clinker by indirect mechanosynthesis process. It consists to combine between mechanical activation of the raw materials (mixture of limestone and clay) and heat treatment less than 900 °C. The equivalent clinker obtained by this method shows the presence of the alite (tricalcim silicate) C3S and belite (dicalcium silicate) C2S and Tricalcium aluminate C3A. CO2 emission by this technique is estimated by 0.3 Ton for 1 Ton of equivalent clinker

Electrical characterization of the junctions P+ N by C-V technique

Technique CV exploits measurement in mode of small signals for a relatively high frequency of the capacity of a junction metal-semi driver or a junction P+ NR (or PN+ polarized in reverse by a tension V R The experimental analysis of this technique makes it possible to determine some electric properties of the junctions P+ N or Schottky. We describe here, the method used and we expose then the results obtained by this technique on diodes containing silicon (Si).Technique CV exploits measurement in mode of small signals for a relatively high frequency of the capacity of a junction metal-semi driver or a junction P+ NR (or PN+ polarized in reverse by a tension V R The experimental analysis of this technique makes it possible to determine some electric properties of the junctions P+ N or Schottky. We describe here, the method used and we expose then the results obtained by this technique on diodes containing silicon (Si)

EFFETS DU TRAVAIL DU SOL SUR LE COMPORTEMENT PHYSIQUE ET BIOLOGIQUE D’UN SOL SOUS UNE CULTURE DE LENTILLE (LENS EXCULENTA) DANS LA RÉGION DE TIARET ALGÉRIE

Soil management practices influence soilphysical and chemicalcharacteristics and bring about changes in the soilmicrobialcommunity structure and function. In thisstudy, the effects of conventional and no-tillage practices on microbialcommunity structure, selectedphysicochemicalpropertiesweredetermined in a continuous corn system on a silt loamsoil. The no-tillage treatmentresulted in highersoilcarbon and nitrogen contents, viable microbialbiomass, at the 0– 25 cm depththan the conventional tillage treatment. Soilmicrobialcommunity structure assessed,using indicative of fungi, bacteria, in the no-till surface soil. Results of principal components analysisbased on soilphysicochemical in agreement. Theseresultsindicatethat tillage practice and soildepthweretwo important factorsaffectingsoilmicrobialcommunity structure and activity, and conservation tillage practices improvebothphysicochemical and microbiologicalproperties of soil

Removal of malachite green from water: Comparison of adsorption in a residue-derived AC versus photocatalytic oxidation with TiO2 and study of the adsorption-photocatalysis synergy

The literature rarely compiles studies devoted to removing pollutants in aqueous media comparing adsorption versus photocatalytic degradation and does not pay enough attention to the analysis of combined adsorption-photocatalytic oxidation processes. In the present manuscript, the removal of malachite green (MG) from aqueous solutions has been investigated in three different cheap and sustainable scenarios: i) adsorption on activated carbon (AC) derived from a residue, luffa cylindrica, ii) photocatalytic oxidation under simulated solar light using titanium dioxide (TP) and iii) combined adsorption-photocatalytic oxidation using TP-AC (70/30 wt/wt.) under simulated solar light. The study has revealed that in the three scenarios and studied conditions, the total removal of this endocrine-disrupting dye from the solution takes place in the assayed time, 2 h, although in some cases just in a few minutes. MG adsorption on the AC is the fastest removal method. MG photocatalytic oxidation with TP also occurs efficiently, although the oxidized MG is not totally mineralized. MG removal using the TP-AC composite under simulated solar light occurs at a rate comparable to that of the MG adsorption on AC, since adsorption is the dominating removal mechanism, more than 90% of the removed MG with TP-AC under simulated solar light is adsorbed in this carbon-containing composite. The obtained results highlight the interest in adsorption, being the selection of the most suitable removal method dependent on several factors (i.e., cost of the AC regeneration, if adsorption, or the toxicity of the intermediate oxidation species, if photooxidation). Paying attention to MG photooxidation with TiO2, comparison of two working photodegradation schemes shows that the direct photodegradation of MG from solution, avoiding any initial dark equilibrium period, is the more efficient option from a time perspective. The use of scavengers has proved that MG photodegradation occurs via an oxidation mechanism dominated by superoxide anion radicals.This work was supported by the following research projects: PID2021-123079OB-I00 (project funded by MCIN/AEI/10.13039/501100011033 and by ERDF A way of making Europe (European Union)), CIPROM/2021/070 (Generalitat Valenciana) and VIGROB-136 (University of Alicante). Souad BOUMAD thanks Mujeres por Africa foundation for the scholarship offer within the 2019 Learn Africa program and, the Ministry of Higher Education and Scientific Research for the 2019–2020 scholarship of the P.N.E. program

Activated Carbon from Stipa tenacissima for the Adsorption of Atenolol

The Stipa tenacissima S. is an endemic species of the Western Mediterranean countries, which grows on the semi-arid grounds of North Africa and South Spain. This biomass offers an abundant, renewable, and low-cost precursor for the production of activated carbon (AC). In that context, ACs were prepared by chemical activation of Stipa tenacissima leaves (STL) using phosphoric acid (H3PO4). The effects of activation temperature and impregnation ratio on the textural and chemical surface properties of the prepared activated carbons were investigated. Activation temperatures of 450 and 500 °C turned out to be the most suitable to produce activated carbons with well-developed porous textures. The best results in terms of developed surface area (1503 m2/g) and micropore volume (0.59 cm3/g) were observed for an STLs to phosphoric acid ratio of 1:2 and a carbonization temperature of 450 °C. The adsorption capacity of the optimal activated carbon was found to be 110 mg/g for the atenolol drug. The adsorption equilibrium was well explained by the pseudo-second-order model and Langmuir isotherm. This study showed that the chemical activation method using H3PO4 as an activating agent was suitable for developing STL-based activated carbon prepared for the removal of atenolol drug in an aqueous solution and compared with commercial activated carbon supplied by Darco

La chirurgie cardiaque mini-invasive vidéo-assistée : une étude comparative à la voie conventionnelle [Less-invasive video-assisted cardiac surgery : a comparative study with the conventional approach]

French Abstract: Introduction-La sternotomie médiane verticale a été la meilleure voie d’abord en chirurgie cardiaque. C’est une voie, traumatisante dotée de plusieurs complications. L’introduction de la caméra a réduit considérablement l’incision. Matériels et méthodes -Dans notre étude, prospective et comparative, 57 patients ont subi une chirurgie cardiaque, répartis en 2 groupes, 30 patients opérés par sternotomie médiane verticale et 27 patients opérés par chirurgie mini-invasive vidéo-assistée. Les données préopératoires, opératoires et postopératoires ont été collectées et analysées. Résultats - l’âge moyen est 49.5+16.3 ans dans le groupe mini-invasive vidéo-assistée et 43.4+16.7 dans le groupe sternotomie médiane verticale. Le signe le plus fréquent était la dyspnée. Les patients asymptomatiques représentent 11% dans le groupe sternotomie médiane verticale et 43% dans le groupe mini-invasive vidéo-assistée.La chirurgie de la valve mitrale dans 63% patients opérés par la mini-invasive vidéo-assistée et 66.6% par sternotomie médiane verticale. La moyenne du temps de la circulation extracorporelle était de119.52+44.5 min dans le groupe mini-invasive vidéo-assistée et 84.53+34.2 min dans l’autre groupe. La moyenne du clampage aortique dans le groupe mini-invasive vidéo-assistée était 94.56+40.8 min et dans le groupe sternotomie médiane verticale était de 59.53+25.5 min. La moyenne de ventilation mécanique était de 4.7+1.8 heures dans le groupe mini-invasive vidéo-assistée et de 7.9±2.4 heures dans le groupe sternotomie médiane verticale. La douleur post-opératoire disparait dans (73%) des cas au 2ème jour postopératoire en mini-invasive vidéo-assistée et dans (70%) au 5ème jour en sternotomie médiance verticale. La moyenne de séjour hospitalier 8.67+3.8 jours en mini-invasive vidéo-assistée et de 13.8+5.0jours en sternotomie médiane verticale. La reprise des activités physiques était très précoce après une chirurgie mini-invasive. Conclusion -la procédure mini-invasive vidéo-assistée est une alternative simple, sûre et efficace. D’excellents résultats sont obtenus avec une faible morbidité. Cette procédure offre une convalescence rapide. English Abstract: Background-Vertical median sternotomy has been the best approach to cardiac surgery. While the conventional approach is traumatic, with many complications, using a video camera in surgery offers smaller incisions. Methods - Our study was a prospective and comparative one. Our sample consisted of 57 patients, divided into 2 groups, including 30 patients operated by vertical median sternomtomy and 27 patients operated by minimally invasive video-assisted surgery. Preoperative, operative and postoperative data were collected and analyzed.  Results -The patients’mean age was 49.5+16.3 years in the minimally invasive video-assisted group and 43.4+16.7 in the vertical median sternotomy group. The most common sign among these patients was dyspnea. Asymptomatic patients represented 11% in the vertical median sternotomy group and 43% in the minimally invasive video-assisted group. Mitral valve surgery was in 63% patients of minimally invasive video-assisted and 66.6% of vertical median sternotomy group. The mean time of cardiopulmonary bypass was 119.52+44.5 min in the minimally invasive video-assisted group and 84.53+34.2 min in the vertical median sternotomy group. The mean time of aortic clamping in the minimally invasive video-assisted group was 94.56+40.8 min while it was 59.53+25.5 min in the vertical median sternotomy group. The mean time of mechanical ventilation was 4.7+1.8 hours in the minimally invasive video-assisted group and 7.9±2.4 hours in the vertical median sternotomy group. Postoperative pain disappeared on the 2nd postoperative day in (73%) of the minimally invasive video-assisted group cases and on the 5th day in (70%) of vertical median sternotomy group cases. The average hospital stay was 8.67+3.8 days in minimally invasive video-assisted and 13.8+5.0 days in vertical median sternotomy group. Faster recovery of physical activities after minimally invasive surgery was reported. Conclusion - The minimally invasive video-assisted is a simpler, safer and more effective procedure with excellent results and low morbidity. This procedure results in a short -er recovery time

La chirurgie cardiaque mini-invasive vidéo-assistée : une étude comparative à la voie conventionnelle [Less-invasive video-assisted cardiac surgery : a comparative study with the conventional approach]

French Abstract: Introduction-La sternotomie médiane verticale a été la meilleure voie d’abord en chirurgie cardiaque. C’est une voie, traumatisante dotée de plusieurs complications. L’introduction de la caméra a réduit considérablement l’incision. Matériels et méthodes -Dans notre étude, prospective et comparative, 57 patients ont subi une chirurgie cardiaque, répartis en 2 groupes, 30 patients opérés par sternotomie médiane verticale et 27 patients opérés par chirurgie mini-invasive vidéo-assistée. Les données préopératoires, opératoires et postopératoires ont été collectées et analysées. Résultats - l’âge moyen est 49.5+16.3 ans dans le groupe mini-invasive vidéo-assistée et 43.4+16.7 dans le groupe sternotomie médiane verticale. Le signe le plus fréquent était la dyspnée. Les patients asymptomatiques représentent 11% dans le groupe sternotomie médiane verticale et 43% dans le groupe mini-invasive vidéo-assistée.La chirurgie de la valve mitrale dans 63% patients opérés par la mini-invasive vidéo-assistée et 66.6% par sternotomie médiane verticale. La moyenne du temps de la circulation extracorporelle était de119.52+44.5 min dans le groupe mini-invasive vidéo-assistée et 84.53+34.2 min dans l’autre groupe. La moyenne du clampage aortique dans le groupe mini-invasive vidéo-assistée était 94.56+40.8 min et dans le groupe sternotomie médiane verticale était de 59.53+25.5 min. La moyenne de ventilation mécanique était de 4.7+1.8 heures dans le groupe mini-invasive vidéo-assistée et de 7.9±2.4 heures dans le groupe sternotomie médiane verticale. La douleur post-opératoire disparait dans (73%) des cas au 2ème jour postopératoire en mini-invasive vidéo-assistée et dans (70%) au 5ème jour en sternotomie médiance verticale. La moyenne de séjour hospitalier 8.67+3.8 jours en mini-invasive vidéo-assistée et de 13.8+5.0jours en sternotomie médiane verticale. La reprise des activités physiques était très précoce après une chirurgie mini-invasive. Conclusion -la procédure mini-invasive vidéo-assistée est une alternative simple, sûre et efficace. D’excellents résultats sont obtenus avec une faible morbidité. Cette procédure offre une convalescence rapide. English Abstract: Background-Vertical median sternotomy has been the best approach to cardiac surgery. While the conventional approach is traumatic, with many complications, using a video camera in surgery offers smaller incisions. Methods - Our study was a prospective and comparative one. Our sample consisted of 57 patients, divided into 2 groups, including 30 patients operated by vertical median sternomtomy and 27 patients operated by minimally invasive video-assisted surgery. Preoperative, operative and postoperative data were collected and analyzed.  Results -The patients’mean age was 49.5+16.3 years in the minimally invasive video-assisted group and 43.4+16.7 in the vertical median sternotomy group. The most common sign among these patients was dyspnea. Asymptomatic patients represented 11% in the vertical median sternotomy group and 43% in the minimally invasive video-assisted group. Mitral valve surgery was in 63% patients of minimally invasive video-assisted and 66.6% of vertical median sternotomy group. The mean time of cardiopulmonary bypass was 119.52+44.5 min in the minimally invasive video-assisted group and 84.53+34.2 min in the vertical median sternotomy group. The mean time of aortic clamping in the minimally invasive video-assisted group was 94.56+40.8 min while it was 59.53+25.5 min in the vertical median sternotomy group. The mean time of mechanical ventilation was 4.7+1.8 hours in the minimally invasive video-assisted group and 7.9±2.4 hours in the vertical median sternotomy group. Postoperative pain disappeared on the 2nd postoperative day in (73%) of the minimally invasive video-assisted group cases and on the 5th day in (70%) of vertical median sternotomy group cases. The average hospital stay was 8.67+3.8 days in minimally invasive video-assisted and 13.8+5.0 days in vertical median sternotomy group. Faster recovery of physical activities after minimally invasive surgery was reported. Conclusion - The minimally invasive video-assisted is a simpler, safer and more effective procedure with excellent results and low morbidity. This procedure results in a short -er recovery time

Advantages of the Incorporation of Luffa-Based Activated Carbon to Titania for Improving the Removal of Methylene Blue from Aqueous Solution

This research aims to study the possible improvement of methylene blue (MB) removal from aqueous solution by hybrid adsorbent-catalysts (AdsCats) prepared through the incorporation of activated carbon derived from Luffa cylindrica fibers (LAC) to TiO2 photocatalysts. LAC with a specific surface area of 1170 m2/g was prepared by chemical activation with phosphoric acid at 500 °C. TiO2/LAC composites with 70 and 90 wt.% Degussa P25 titania content were prepared. The materials were characterized by N2 physical adsorption, XRD, FTIR, and XPS. The AdsCats displayed a very good dispersion of TiO2 over LAC, a surface area of close to 200 or 400 m2/g, depending on the composition, and high crystallinity, showing the presence of anatase and rutile phases. MB removal was studied in two different scenarios: under UV-light after reaching adsorption equilibrium, and under UV-light once the liquid effluent and the AdsCats were in contact. The MB removal by LAC has proved to be very efficient, highlighting the predominant role of adsorption over photodegradation. The prepared AdsCats have also been compared with their components. The results showed that TiLAC hybrids have superior photocatalytic performance than P25, showing TiLAC-7/3 90% MB removal with respect to the initial concentration just after 30 min of UV light irradiation for both studied scenarios.This research was funded by Ministry of Science, Innovation and Universities, projects RTI2018-099668-BC22 and RTI2018-095291-B-I00, Junta de Andalucía, project MA18-FEDERJA-126 and FEDER funds, and GV/FEDER (PROMETEO/2018/076). S.B. acknowledges Mujeres por Africa foundation for the scholarship offer within the 2019 Learn Africa program and, the Ministry of Higher Education and Scientific Research for the 2019–2020 scholarship within the P.N.E. program