Mineralogical Analysis of Sand Roses and Sand Dunes Samples from Two Regions of South Algeria

Silicon - In this work, it is found that the important minerals in sand dunes and sand roses samples from Anqousa in the south-east of Algeria in Ouargla region and from Charouin in the south-west...     

Chemometric Characterization of Eight Monovarietal Algerian Virgin Olive Oils

Differences in triacylglycerol, fatty acid, squalene, and tocopherol compositions were demonstrated between 8 varieties of virgin olive oils (Aberkane, Aguenaou, Aharoun, Aimel, Bouchouk Guergour, Bouichret, Chemlal, and Sigoise) from Petite Kabylie area, north eastern Algeria. Fatty acid and triacylglycerol morphotypes characterized each variety. A principal component analysis, based on triacylglycerol, fatty acid, and squalene compositions, differentiates between varieties. Minor fatty acids and squalene, usually not taken into account individually in authentication studies, are strongly involved in this differentiation, whereas the discriminant power of tocopherols is weak. Soft Independent Modeling of Class Analogy classification using chemical compositions as variables showed a high potential to authenticate the varietal origin of Algerian virgin olive oils.     

Characterization of Algerian Hassi-Messaoud asphaltene structure using Raman spectrometry and X-ray diffraction

Asphaltenes derived from Algerian oil wells were characterized by Raman spectrometry to investigate their molecular structures in solid-state. The aromatic sheet diameter (L_a) was estimated using the integrated intensities of the G and the D1 mode, along with the Tuinstra equation [Tuinstra F, Koenig JL. J Chem Phys 1970;53:1126]. The values obtained for three Algerian Hassi-Messaoud asphaltene samples are on the same order as the literature values and also consistent with the X-ray diffraction results. The Raman spectra corresponding to the G and the D bands can be fitted with Gaussian, Lorentzian, and Gaussian/Lorentzian hybrid functions in a self-consistent manner. A three peak fitting procedure found that the Gaussian/Lorentzian hybrid function with G being Gaussian and D Lorentzian is the best combination. Incorporation of the X-ray data on the height of the crystallite, L_c, gives rise to an estimate of eight asphaltene molecules in each asphaltene aggregate.     

Clinical and Molecular Characterization of Patients with Mucopolysaccharidosis Type I in an Algerian Series

Mucopolysaccharidoses (MPS’s) represent a subgroup of lysosomal storage diseases related to a deficiency of enzymes that catalyze glycosaminoglycans degradation. Mucopolysaccharidosis type I (MPS I) is a rare autosomal recessive disorder caused by a deficiency of α-l-iduronidase encoded by the IDUA gene. Partially degraded heparan sulfate and dermatan sulfate accumulate progressively and lead to multiorgan dysfunction and damage. The aim of this study is to describe the clinical, biochemical, and molecular characteristics of 13 Algerian patients from 11 distinct families. MPS I diagnosis was confirmed by molecular study of the patients’ IDUA gene. Clinical features at the diagnosis and during the follow-up are reported. Eighty-four percent of the studied patients presented with a mild clinical phenotype. Molecular study of the IDUA gene allowed the characterization of four pathological variations at the homozygous or compound heterozygote status: IDUA NM_00203.4:c.1598C>G-p.(Pro533Arg) in 21/26 alleles, IDUA NM_00203.4:c.532G>A-p.(Glu178Lys) in 2/26 alleles, IDUA NM_00203.4:c.501C>G-p.(Tyr167*) in 2/26 alleles, and IDUA NM_00203. 4: c.1743C>G-p.(Tyr581*) in 1/26 alleles. This molecular study unveils the predominance of p.(Pro533Arg) variation in our MPS I patients. In this series, the occurrence of some clinical features linked to the Scheie syndrome is consistent with the literature, such as systematic valvulopathies, corneal opacity, and umbilical hernia; however, storage signs, facial dysmorphic features, and hepatomegaly were more frequent in our series. Screening measures for these debilitating diseases in highly consanguineous at-risk populations must be considered a priority health problem.     

Study of Heat Effect on the Composition of Dunes Sand of Ouargla (Algeria) Using XRD and FTIR

The spectra of x-ray diffraction (XRD) and infrared spectroscopy (FTIR) shows that the dunes sand of Ouargla’s region consists naturally of crystalline structures of α-quartz and gypsum, as well as other uncrystallized compounds with low concentrations like kaolinite and hematite, in addition to some organic compounds. The sand heating process at temperatures between 200 and 1200 °C affects its composition. By heating at 200 °C crystalline phases of anhydrite and bassanite appear due to the continuing loss of water from the gypsum. All the gypsum transforms into anhydrite, and the kaolinite transforms into metakaolin because of the breaking of the OH bond, producing water vapor by heating in the range of 400–800 °C. The heating at 1000 °C disassembles the kaolinite into aluminium-silicon and cristobalite, and leads to the emergence of a new crystalline phase related to wollastonite resulting from the start of a reaction between the anhydride and the quartz. Heating at 1200 °C leads to the disappearance of all the anhydrite because of its interaction with the quartz, producing the wollastonite and the release of sulfur dioxide SO₂ and oxygen O₂, in addition to the increase of the cristobalite proportion because of the disintegration of all the kaolinite into mullite and cristobalite, or the transformation of quartz phase into cristobalite. Also occuring is an interaction between the hematite and the quartz producing the ferrosilite characterized by its green color.     

新型PVC/细沙复合材料的制备及性能研究

以细沙为填料,采用熔融共混法制备PVC/细沙复合材料。研究了细沙预处理、细沙表面改性,以及细沙与PVC的质量比对PVC/细沙复合材料的力学性能和耐热性的影响。结果表明:PVC/细沙复合材料的维卡软化点为100.4℃,冲击强度为21.75kJ/m2,拉伸强度为308.5 MPa,细沙填料提高了PVC的热分解温度。     

Characterization and Antioxidant Properties of Six Algerian Propolis Extracts: Ethyl Acetate Extracts Inhibit Myeloperoxidase Activity

Because propolis contains many types of antioxidant compounds such as polyphenols and flavonoids, it can be useful in preventing oxidative damages. Ethyl acetate extracts of propolis from several Algerian regions show high activity by scavenging free radicals, preventing lipid peroxidation and inhibiting myeloperoxidase (MPO). By fractioning and assaying ethyl acetate extracts, it was observed that both polyphenols and flavonoids contribute to these activities. A correlation was observed between the polyphenol content and the MPO inhibition. However, it seems that kaempferol, a flavonoid, contributes mainly to the MPO inhibition. This molecule is in a high amount in the ethyl acetate extract and demonstrates the best efficiency towards the enzyme with an inhibiting concentration at 50% of 4 ± 2 μM.     

Characterization of Waste and Reclaimed Green Sand Used in Foundry Processing

Silicon - The aim of this study is to discuss the importance of characterization of green, waste green and reclaimed sand. The transformations and changes which take place in the green sand, are...     

Algerian kaolinite used for mullite formation

In the present study, mullite was synthesized through reaction sintering of Algerian kaolinite and high purity alumina. The raw powders were wet ball milled in a planetary ball mill. Powders' morphology and the microstructure of the sintered samples were characterized by means of a scanning electron microscope. An X-ray diffractometer equipped with a heating facility and a differential thermal analyzer were used to follow mullite formation. Cylindrical specimens were produced by uniaxial cold compaction at a pressure of 75 MPa and sintered at different sintering temperatures for different sintering times. The heating rate was 10 °C/min. It was found that Algerian kaolinite was suitable for mullite production through reaction sintering with pure Al₂O₃. Formation of complete mullite occurred at 1550 °C. A relative density of 94% (of the theoretical density) was achieved at a relatively low sintering temperature of 1600 °C and a sintering time of 4 h.     

有机硅改性酚醛树脂固砂剂的制备、表征及固砂性能

以苯酚和甲醛为原料、草酸为催化剂合成线性酚醛树脂;然后与环氧氯丙烷反应,在酚羟基上引入环氧基团,得到环氧酚醛树脂;再与γ-氨丙基三乙氧基硅烷(KH-550)发生开环反应,引入有机硅功能基团,制备了有机硅改性酚醛树脂。通过FTIR对其结构进行了表征,并对其固砂性能(抗压强度、渗透率保持率和耐介质性)进行了考察。结果表明,在树脂用量为6%、固化温度为45℃、固化时间为48h时制得的胶结岩心抗压强度达到8.8 MPa,渗透率保持率达到80%,具有较强的抗酸、抗碱、抗盐和抗氧化性能。     

Chromatic Classification of Ouargla (Algeria) Dunes Sand: Determination of Main Compositions and Color Causes,by Using XRD,FTIR and XRF

In the present work, a manually chromatic classification of Ouargla dunes sand has been carried out. According to its visual color, eight chromatic types of sand have been obtained: transparent (yellow, orange and red), and opaque (white, milky, gray, black and red). According to the main chemical compositions of sand, both XRD and FTIR have divided the chromatically sorted sand into three groups: quartzite (transparent samples), calcareous (milky, gray and black opaque samples) and calcareous quartzite (white and red opaque samples), without possibility of distinguishing between the sorted samples. FTIR spectroscopy has shown all functional groups and vibration modes in these samples. XRF spectroscopy has shown that sand grain colors are closely related to the main compositions as well as the impurities. It has also been shown that transparent samples contain more than 92 % of quartz (SiO ₂). The redness of transparent samples is proportional to iron (Fe) impurities. It has also been shown that milky, gray and black opaque samples contain more than 55 % of calcium oxide (CaO). The milky color is due to magnesium (Mg) and sulfur (S), whereas the blackness is due to iron (Fe) and manganese (Mn). Both white and red opaque samples contain approximately equal concentrations of quartz and calcite, whilst the redness refers to the high concentration of iron (Fe), whereas the whiteness is due to the presence of magnesium (Mg).     

酯硬化水玻璃砂的特征与除尘系统设计

针对酯硬化水玻璃砂混砂造型工序中,水玻璃（Na2O·mSiO2·nH2O）与有机酯固化剂（R—COOR’）作用,生成有机酸钠（R—COONa）、有机醇（R’-OH）、硅溶胶（mSiO2·nH2O）,进而在浇铸及焙烧过程中,大部分分解为氧化钠（Na2O）和石英（SiO2）残留在旧砂中,非常容易引起滤袋堵塞,对除尘系统的运...     

Removal of Orange II by Phosphonium-modified Algerian Bentonites

An Algerian montmorillonite was modified with two organic surfactants, methyltriphenyl phosphonium bromide and n-hexyltriphenyl phosphonium bromide. The solids obtained were used as adsorbents to remove Orange II, an anionic dye from aqueous solutions. Batch experiments were conducted to study the effects of temperature (20–60°C), initial concentration of adsorbate (50–150 mg L^?1) and pH of solution 6.5 on dye adsorption. Due to their organophilic nature, exchanged montmorillonites were able to adsorb Orange II at a very high level. Adsorption of Orange II for B-NHTPB and B-MTPB at different pH show that the adsorption capacity clearly decreases with an increase in pH of the initial solution from 2 to 8, this decrease being dramatic for pH > 8. This may be due to hydrophobic interactions of the organic dye with both phosphonium molecules and the remaining non-covered portion of siloxane surface. The kinetics of the adsorption was discussed on the basis of three kinetic models, i.e., the pseudo-first-order, the pseudo-second-order, and the intraparticle diffusion models. Equilibrium is reached after 30 min and 60 min for B-MTPB and B-NHTPB, respectively; the pseudo-second-order kinetic model described very well the adsorption of Orange II on modified bentonites. The non-linear Langmuir model provided the best correlation of experimental data, maximum adsorption of Orange II is 53.78 mg g^?1 for B-NHTPB and 33.79 mg g^?1 for B-MTPB. The thermodynamic parameters, such as free energy of adsorption (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were also determined and evaluated. From thermodynamic studies, it was deduced that the adsorption was spontaneous and exothermic.