Box-Behnken design to enhance the corrosion resistance of high strength steel alloy in 3.5 wt.% NaCl solution

Recently, the production of green corrosion inhibitors and green inhibition strategies is highly demanded in the field of science and technology due to the growing demand of green chemistry. Usage of plant extracts as metallic corrosion inhibitors has attracted considerable attention in the last few decades. Plant products are perfect green candidates for replacing traditional toxic corrosion inhibitors. Reduced environmental risk, lower cost, widespread availability and high corrosion inhibition efficiency make plant extracts ideal candidates for the substitution of costly and harmful traditional synthetic corrosion inhibitors. An aqueous extract of plant material Henna (Lawsonia Inermis) powder was used as a corrosion inhibitor to control the corrosion of high strength steel immersed in an aqueous solution containing 35000 ppm Cl−, by electrochemical methods in the absence and presence of the inhibitor. Lawsone is the principal constituent of this plant extract. This has excellent efficiency in inhibition and displays excellent IE at neutral pH. Electro-chemical experiments such as potentiodynamic polarization and impedance were used to describe the mechanistic aspects of corrosion inhibitions. Box-Behnken method was used to investigate the effect of key parameters (i.e. concentration of inhibitors, temperature, and speed of rotation) on the efficiency of inhibition and corrosion rate of high strength steel alloy in 3.5 wt.% NaCl solutions. From electrochemical measurements and statistical analysis, it was found that the efficacy of inhibition improves with higher inhibitor concentration, low rotation speed and low temperature. The Lawsonia Inermis extracted demonstrated strong corrosion inhibition in saline media for high strength steel alloy and reached 81.68

Microstructure and Mechanical Behavior of Hot Pressed Cu-Sn Powder Alloys

Cu-Sn based alloy powders with additives of elemental Pb or C were densified by hot pressing technique. The influence of densifying on the properties of the hot pressed materials was investigated. The properties, such as the hardness, compressive strength, and wear resistance of these materials, were determined. The hot pressed Cu-Sn specimens included intermetallic/phases, which were homogeneously distributed. The presence of graphite improved the wear resistance of Cu-Sn alloys three times. Similarly, the presence of lead improved the densification parameter of Cu-Sn alloys three times. There was no significant difference in the mechanical behavior associated with the addition of Pb to the Cu-Sn alloys, although Cu-Pb alloys showed considerably higher ultimate strength and higher elongation. The Cu-Sn-C alloys had lower strength compared with those of Cu-Sn alloys. Evidence of severe melting spots was noticed in the higher magnifications of the compression fracture surface of 85% Cu-10% Sn-5% C and 80% Cu-10% Sn-10% Pb alloys. This was explained by the release of load at the final event of the fracture limited area

Study of the Traditional Argan Oil Oxidation under Different Storage Conditions

The autoxidation of argan oil extracted traditionally was followed during a long-term storage, using plastic bottles in presence of air, under nitrogen atmosphere or at 4 °C, in comparison with transparent glass bottles. The autoxidation was evaluated by the simultaneous monitoring of four parameters for a period of 18 months: tocopherols content, oleic and linoleic acids, conjugated dienes and peroxide value.The results showed that the storage in plastic bottles in the light at room temperature, delayed the oxidative degradation of the oil relatively to the transparent glass. This degradation was mitigated by the presence of nitrogen. The maximum content of hydroperoxides, resulting from the degradation of unsaturated fatty acids, was reached after 306 days in the presence of air and 321 days in the presence of nitrogen in the plastic bottles. This effect was recorded only after 273 days in the glass vials. Conjugated dienes changed in the same way as hydroperoxides. The degradation of unsaturated fatty acids taked place after the destruction of tocopherols including ?-tocopherol, which was the major form in the argan oil. The shelf life of the oil was longer (over 18 months) when plastic bottles were placed at 4 °C. The results showed that argan oil extracted traditionally had high stability against the oxidation due to its richness in tocopherols which are powerful antioxidants. Keywords: Argan oil, glass, nitrogen, oxidation, plastic, storage, temperatur

Quantitative and Qualitative Analysis by HPLC of Major Peganum harmala Alkaloids at Different Stages of Development

The analysis of major Peganum harmala alkaloids (harmaline, harmine, harmol and harmalol) has shown that the content of these secondary metabolites depends on the plant development stage. The qualitative and quantitative profile of major alkaloids change significantly between stems, leaves and roots. The roots and seeds are the richest and most diversified organs in these metabolites. The concentration of the major alkaloids in all organs increases during the first three weeks and stabilizes at a constant level during vegetative growth phase and then decline at the beginning of flowering. On the scale of the whole plant, major alkaloids concentration of P. harmala varies with the developmental stage of the plant between 21.16 and 26.96 mg/g and harmine remains the most abundant molecule. Optimum exploitation of these natural products from the P. harmala plant is possible if the harvest of plant material occurs during the vegetative growth phase and at the appropriate stage for the richest organ. Keywords: Peganum harmala, Plant growth, Alkaloids, Harmine, Harmaline, Harmol, Harmalo

Origin of Amphibole-Biotite-Fluorite-Rich Enclaves from Gabal El-Ineigi Fluorite-Bearing Granite, Central Eastern Desert of Egypt: Insights into Fluoride-Calcium and Silicate Liquid Immiscibility

Gabal El-Ineigi fluorite-bearing rare-metal granite with A-type affinity, located in the Central Eastern Desert of Egypt, is distinguished by its abundance of large fluorite-quartz veins and mafic enclaves. Plagioclase (labradorite to oligoclase), Mg-rich biotite, and Mg-rich hornblende are the main components of mafic enclaves, with significant amounts of fluorite as essential phases, and titanite and Fe-Ti oxides (Nb-free rutile and ilmenite-rutile solid solution) as the main accessories. These enclaves are monzodioritic in composition, Si-poor, and highly enriched in Ca, Fe, Mg, and F compared to the host alkali feldspar F-poor Si-rich granites. Given the conflicting evidence for a restitic, xenolithic, magma mixing/mingling, cumulate, or bimodal origin for these enclaves, we propose that the mafic enclaves and felsic host granites are two conjugate liquids, with contrasting compositions, of a single parental melt. This is inferred by the normalized REE patterns that are similar. As a result, liquid immiscibility is proposed as a probable explanation for this mafic–felsic rock association. These enclaves can be interpreted as transient melt phases between pure silicate and calcium-fluoride melts that are preserved from the early stages of separation before evolving into a pure fluoride (Ca-F) melt during magma evolution. Due to element partitioning related to melt unmixing, the enclaves are preferentially enriched in Ca, F, Li, Y, and REE and depleted in HFSE (such as Zr, U, Th, Ta, Nb, Hf, and Ga) in comparison to the host granites. Furthermore, mafic enclaves exhibit W-type tetrad effects, while host granites exhibit M-type tetrad effects, implying that the REE partitioning, caused by liquid immiscibility, is complementary

Etude de l'extraction de l'huile de Cactus

Généralement en été, les quantités en figues de barbarie se trouvent en surabondance dans les lieux de production plus que sur les lieux de vente. Les lieux de production se trouvent loin de ceux de consommation et les périodes de récolte coïncident avec les moments les plus chauds de l'année. Ces facteurs facilitent l'altération des fruits par divers phénomènes physiques, chimiques et microbiologiques, ce qui entraîne d'énormes pertes pour les producteurs. Les rejets de fruits sont des sources de graines riches en huile

Characteristics of Cold and Hot Pressed Iron Aluminum Powder Metallurgical Alloys

Iron powders having average particle sizes of ~40 µm are mechanically mixed thoroughly with aluminum powders ranging from 1 to 10 in wt. %, with an average particle size of ~10 µm. Two different powder metallurgy (PM) techniques, cold and hot pressing, are used to study the effect of the additive element powder on the mechanical properties, wear properties, and the microstructure of the iron based alloys. The hot pressing technique was performed at a temperature reaching up to 500 °C at 445.6 MPa. The cold pressing technique was performed at 909 MPa at room temperature. By increasing the Al content to 10 wt. % in the base Fe-based matrix, the Brinell hardness number was decreased from 780 to 690 and the radial strength from 380 to 228 MPa with reductions of 11.5% and 40%, respectively. Improvement of the wear resistance with the increase addition of the Al powder to the Fe matrix up to five times was achieved, compared to the alloy without Al addition for different wear parameters: wear time and sliding speed

Détermination de la stabilité de l'huile de Cactus

Les travaux que nous avons effectués sur l'étude de l'oxydation et de la conservation des huiles ont montré que l'huile d'argan peut être conservée pour une durée de 400 jours sous azote et à l'obscurité. Les travaux que nous avons effectués sur l'étude de l'oxydation et de la conservation des huiles ont montré que l'huile d'argan peut être conservée pour une durée de 400 jours sous azote et à l'obscurité

Valorisation des ordures ménagères sous forme énergétique

The household refuse of Agadir city have a high level of moisture and contain large amount of organic materials witch can be used in agriculture. Nevertheless, the plastic waste account for about 10.7 % percent by weight of domestic waste and poses an inconvenient to physical characteristics of the municipal solid waste compost. This work aims to sort by resin type various plastics packaging by using differential scanning calorimetry and to evaluate their heat of combustion by thermometric calorimetry. Experimental results chow a siginificant part of polyethylene containers that can be recycled. The plastics with very small volume chow a very heterogeneous composition but have a high heat value, approximately two times greater than to heat released by wood. Plastics burn with very little ash but most environmental concerns associated with their combustion have been related to gas emissions. Those are analysed by gas chromatography