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Purpose. In this work, the influence of flotation reagents on the separation yield of the phosphate-carbonate system is studied. The investigation is conducted by the reverse flotation process in double stage of the phosphate ores from the Jebel Onk deposit-Algeria. Methodology. The experimental part can be divided into three aspects, a mechanical preparation of the samples, and flotation tests in the first stage followed by a double flotation and, finally, characterization of the flotation products by different physicalchemical analysis techniques. Findings. Reverse flotation double stage process was applied on two classes of phosphate ores (C1: 40–250 and C2: 250–500 μm). The samples are constituted by phosphatic elements (apatite), cemented by a mixture of a great amount of dolomite with low amounts of quartz, clay and calcite. Flotation results showed that P2O5 recovery was higher for C2 compared to C1. Thus, oleic acid and double tartrate of sodium-potassium could be considered as the best reagent since the P2O5 recovery content corresponds to 29.27 and 31.25 % for C1 and C2, respectively. Compared to the oleic acid and pine oil reagent, the recoveries of P2O5 were 28.85 and 30.55 % for C1 and C2, respectively. However, when other reagents as (oleic acid + phosphoric acid) and (oleic acid + diesel fuel) were used, the recovered amount of P2O5 was found to be less important, 27.80 and 27.10 % for class C1, and 30.14 and 29.15 % for C2, respectively. Originality. During this study two main axes were discussed: the first one was the influence of flotation reagents on flotation of the first and second stages, the second one was to study the effect of grain size on the flotation yields. The flotation process has been shown to be effective both in terms of depressed phosphate elements in the phosphate concentrates and in gangue floated in the flotation tailings. It can be seen that the concentrate contents of around 32 % is achieved in P2O5 with superior recoveries of 99 %. Practical value. The results of analyses carried out on the flotation products showed, in most cases, that the streams are richer in phosphate elements (fluorapatite, carbonate hydroxylapatite, carbonate fluorapatite) and a low amount of carbonates (dolomite and calcite), unlike floating, mainly made up of dolomite with a small amount of phosphated elements. [ABSTRACT FROM AUTHOR]

يقدم المقال نرجمة لمقال فلسفة الدين، لأنطوان فيرغوت، وهو مقال يهتم بكيفَ أنَّ فكرةَ المطلقِ قد أثرَ فيها كُلٌ من التطورِ الداخليِّ للبحثِ الأنطولوجيّ وكذا التحري العلميِّ للأديانِ. أما الحيّزُ الثاني الذي يضم مجموعَ علومِ الإنسانِ فقد أثرت [علومه هاته] بعمقٍ، بفضلِ ازدهارهِا في الأزمنةِ الحديثةِ، على الفكرِ الدينيّ، سواء بمراحلهِا النقديةِ [الملحةِ] أو بالإمكانياتِ الجديدةِ التي اقترحتها عليه. وفي الأخير سنأتي، على سبيل الختامِ، إلى التفكيرِ في أساسِ النزعةِ الإنسانيةِ، ففيه تتجلى بوضوح أكثرُ الخلافاتِ بين مختلِفِ أصنافِ الفلسفاتِ.

La necesidad de responder a los problemas ambientales causados por los rechazos mineros, muchos enfoques llevados a cabo para resolver estos problemas. En este trabajo, se estudió el relave de mineral de oro proporcionado por la mina Amesmessa como sustitución en el mortero de cemento. Las cantidades de sustitución estudiadas fueron 0, 10, 20, 30 y 40 % del cemento en peso. Se relevó la composición mineralógica de las principales fases de la hidratación del cemento. Se realizaron pruebas experimentales como la compresión, la porosidad y la absorción de agua. Las pruebas revelaron que la sustitución del cemento al 10% es la cantidad óptima para sustituir el cemento. Se demostró una resistencia a la compresión de 33 Mpa, una porosidad de 10,31% y una absorción de agua de 4,83%. Estos valores se acercan a los de las muestras de referencia. Esta sustitución permite preservar el medio ambiente desde dos puntos de vista, mediante la valorización de los residuos de mineral de oro y la disminución de la emisión de CO2 con la disminución de la producción de cemento. Abstract The need to respond the environmental problems causing by mining rejects, many approaches carried out to resolve these problems. In this work, we studied the gold ore tailing provided by Amesmessa mine as replacement in cement mortar. The substitution amounts studied 0, 10, 20, 30, and 40 % of cement in weight. The mineralogical composition was relieved the principal phases of the cement hydration. Experimental tests carried out such as compressive, porosity, water absorption. The tests revealed that the replacement of cement at 10% percent is the optimum amount to replace cement. It showed 33 Mpa of compressive strength, 10.31% porosity, 4.83% water absorption. These values are so close to those of reference samples. This substitution allows preserving the environment from two sides, by valorizing the gold ore tailing and diminishing the CO2 emission with diminishing the cement production.

The main objective of this work is to study the mechanical characteristics and the chemical degradation of mortars and concretes made obtained by substituting the cement by the machining sludge. Several materials were carried out by substituting the cement with different amount of machining sludge (5, 10, 15 and 20%). The obtained materials are compared to those without substitution (ie: 00wt% of machining sludge). Mechanical and physical properties of the two materials (mortars and concretes) as flexural and compressive strengths were studied. Physical properties as shrinkage, the bloating effect, loss in mass, slump concretes and porosity were evaluated. In addition, chemical degradation is studied for the conservation of these concretes and mortars from machining sludge in different aggressive environment. Moreover, the addition of 5wt% of the machining sludge in the mixture of the mortar and the concretes seems to be interesting.

Abstract Objective To investigate the effects of hemodialysis (HD) and periotoneal dialysis (PD) on oxidative stress in chronic renal failure patients (CRF). Methods 20 HD patients (M/F: 8/12, 36 ± 12 years) and 20 PD patients (M/F: 10/10, 40 ± 8 years) were compared with 20 end stage renal failure patients (CRF) (M/F: 4/16, 61 ± 13 years). Results Thiobarbituric acid reactive substances (TBARS) values were elevated in HD and decreased in PD compared to CRF (P < 0.05). TBARS-VLDL and TBARS-HDL2 were decreased in HD and PD, compared to CRF (p < 0.05). TBARS-LDL were higher in HD compared to CRF (p < 0.05). No significant difference in TBARS-HDL3 values between the three groups. Carbonyls were increased in HD (p < 0.05) and PD (p < 0.01) compared to CRF. Plasma superoxide dismutase activity (SOD) was decreased in HD compared to CRF and PD (P < 0.05). Glutathion peroxidase activity (GSH-Px) was decreased in HD and PD (P < 0.005), compared to CRF. Decrease in catalase activity was noted only in PD compared to CRF (P < 0.05). An increase in nitric oxide was noted in HD compared to CRF (p < 0.05). Albumin concentrations were higher in HD and PD compared to CRF (P < 0.001). Whereas uric acid concentrations were decreased in HD (P < 0.001) compared to CRF and PD. Bilirubin values were similar in all groups. Increased values of iron were noted in HD and PD, compared to PD (p < 0.001). Conclusion HD and PD aggravate oxidative stress generated by uremia. HD accentuates lipid and protein peroxidation, while PD aggravates protein oxidation. However, the activity of antioxidant enzymes was altered by both dialysis treatments.

The groundwater salinization process complexity and the lack of data on its controlling factors are the main challenges for accurate predictions and mapping of aquifer salinity. For this purpose, effective machine learning (ML) methodologies are employed for effective modeling and mapping of groundwater salinity (GWS) in the Mio-Pliocene aquifer in the Sidi Okba region, Algeria, based on limited dataset of electrical conductivity (EC) measurements and readily available digital elevation model (DEM) derivatives. The dataset was randomly split into training (70%) and testing (30%) sets, and three wrapper selection methods, recursive feature elimination (RFE), forward feature selection (FFS), and backward feature selection (BFS) are applied to train the data. The resulting combinations are used as inputs for five ML models, namely random forest (RF), hybrid neuro-fuzzy inference system (HyFIS), K-nearest neighbors (KNN), cubist regression model (CRM), and support vector machine (SVM). The best-performing model is identified and applied to predict and map GWS across the entire study area. It is highlighted that the applied methods yield input variation combinations as critical factors that are often overlocked by many researchers, which substantially impacts the models' accuracy. Among different alternatives the RF model emerged as the most effective for predicting and mapping GWS in the study area, which led to the high performance in both the training (RMSE = 1.016, R = 0.854, and MAE = 0.759) and testing (RMSE = 1.069, R = 0.831, and MAE = 0.921) phases. The generated digital map highlighted the alarming situation regarding excessive GWS levels in the study area, particularly in zones of low elevations and far from the Foum Elgherza dam and Elbiraz wadi. Overall, this study represents a significant advancement over previous approaches, offering enhanced predictive performance for GWS with the minimum number of input variables., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The cellulose is the most abundant and renewable polymer in nature. It is characterized by its biodegradability that can help to establish a friendly environment. The main objective of this study is intended to characterize the nanocellulose obtained from waste date palm,  including the dried palms (DP) and the fresh palms (FP) by implementing chemical methods (hydrolysis with H2SO4). Physical properties, morphology, the elemental composition and the thermal stability were determined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta sizer, scanning electron microscopy (SEM), whereas energy dispersive X-ray (EDX) and thermogravimetric analysis (TGA), respectively. FTIR, SEM and EDX results, revealed the effective removal of impurities, hemicellulose and lignin. Palm sample residues contained 35.99% of cellulose and 33.12% of cellulose nanocrystals (CNC) for DP, and 36.17% of cellulose and 34.35% of CNC for FP. The CNCs have higher crystallinity than the raw fibers and Zeta sizer was between 25 and 1150 nm. TGA analysis showedthat DP exhibited greater thermal resistance.

In the present work, the development of geopolymeric materials with Na or K based on industrial kaolin samples, with variable kaolinite content and alkaline silicates, is studied. XRF, XRD, FTIR and SEM-EDS have been used as characterization techniques. Three ceramic kaolin samples, two from Algeria and one from Charente (France), have been considered. In particular, chemical and mineralogical characterization revealed elements distinct of Si and Al, and the content of pure kaolinite and secondary minerals. Metakaolinite was obtained by grinding and sieving raw kaolin at 80 μm and then by thermal activation at 750 °C for 1 h. This metakaolinite has been used as a base raw material to obtain geopolymers, using for this purpose different formulations of alkaline silicates with NaOH or KOH and variable Si/K molar ratios. The formation of geopolymeric materials by hydroxylation and polycondensation characterized with different Si/Al molar ratios, depending on the original metakaolinite content, has been demonstrated. Sodium carbonates have been detected by XRD and FTIR, and confirmed by SEM-EDS, in two of these geopolymer materials being products of NaOH carbonation., Competing Interests: The authors declare no conflicts of interest.