Purification,structural data and biological properties of polysaccharide from Prunus amygdalus gum

This work demonstrates the efficiency of almond gum polysaccharides (AGPs) as bioactive compounds. AGPs were first extracted using H₂O₂, in the presence of NaOH, at different times and temperatures. The optimal extraction conditions were 4% H₂O₂ and 2 N NaOH, for 7 h at 50 °C, leading to an extraction yield of 58.2% (w/w). After a purification step, the retained AGPs were characterised using high‐performance liquid chromatography showing a molecular weight of 99.3 kDa. The monosaccharide composition of AGPs were assessed using gas chromatography–mass spectrometry. AGPs were found to be a complex heteropolysaccharide with a repeating unit mainly composed of galactose, arabinose, xylose, mannose, rhamnose, and glucuronic acid with the respective ratios: 45:26:7:10:1:11. The acidic nature of the polysaccharide is due to the presence of glucuronic acid. Total antioxidant activity, free radical‐scavenging activity and reducing power assay of AGPs were investigated. The obtained results showed high antioxidant activities of AGPs. Furthermore, beyond 60 mg mL^?1, AGPs exhibited bacterial growth inhibition for five pathogenic strains: Escherichia coli, Staphylococcus aureus, Enterococcus feacalis, Pseudomonas aeruginosa and Salmonella typhimurium.     

Polymerization of 2-phenyl-aziridine

Summary The ring-opening polymerization of 2-phenyl aziridine was studied with several catalyst systems: boron trifluoride etherate, chlorhydric acid, perchloric acid, dimethyl sulfate and methyl triflate. The corresponding polyamine was obtained as a pale yellow solid with a number average molecular weight around 2,000–3,000.A kinetic study is discussed in the case of perchloric acid and methyl triflate.     

Prediction of visual attention with deep CNN on artificially degraded videos for studies of attention of patients with Dementia

Multimedia Tools and Applications - Studies of visual attention of patients with Dementia such as Parkinson’s Disease Dementia and Alzheimer Disease is a promising way for non-invasive...     

Energy management strategy in cloud computing: a perspective study

Optimizing energy consumption in cloud computing is yet a challenge despite the diversity of the proposed energy management strategies. Indeed, and during our related work study we have observed that the different elements or components which should be considered in order to be able to properly manage energy consumption in a cloud computing context are not well defined and/or discussed in terms of importance. This makes the proper classification and/or comparison of the different proposed strategies or techniques very difficult. Consequently, this paper aims, on the one hand, at defining and discussing properly such components in order to create a guideline and, on the other hand, to ease both the classification and the comparison of these proposed strategies and techniques. Second and after discussing some common weaknesses related to the current energy consumption optimization techniques and methods, this paper proposes energy-saving technique which uses a novel load detecting policy. This policy is based on the median absolute deviation method which uses the median and the standard deviation to calculate upper and lower thresholds which aim to classify hosts into either overloaded or under-loaded state. Simulation results have shown better results of the proposed technique compared to the existing ones especially in reducing energy consumption and the number of virtual machine migrations in addition to better active host time. Indeed, we found that the average of saved energy is around 40% compared to the built in techniques in cloudSim.     

Effects of almond gum as texture and sensory quality improver in wheat bread

The aim of this work was to investigate the effect of almond gum as dietary fibre source in enhancing the wheat bread quality. Different amounts of almond gum (2%, 5% and 10% (w/w)) were used in bread formulation. The volume, texture, crust and crumb colour, as well as the sensorial properties, were evaluated and compared to control (without almond gum). The obtained results showed that almond gum addition enhanced significantly the volume of bread. The highest volume was obtained using 2% almond gum concentration with 23.6% increase, compared to control. Using almond gum in bread formulation improved considerably its texture with a notable decrease in hardness by 61.7% and 42.5% when using 2% and 5% almond gum, respectively. The sensory analysis scores showed that the better overall acceptability was found for breads supplemented with 2% almond gum, as compared to control and breads supplemented with 5% or 10% almond gum.     

Optimising operating conditions in ultrafiltration fouling of pomegranate juice by response surface methodology

The resistance‐in‐series model was used to analyse flux behaviour, which involved the resistances of membrane itself, the fouling and solute concentration polarisation. Response surface methodology was used to establish the relationships between operating parameters and ultrafiltration (UF) efficiency and thus to determine optimal conditions. Experiments were performed according to Box–Behnken design by changing the levels of three parameters, namely transmembrane pressure, feed flow rate and temperature. The fitted mathematical models allowed us to plot isoresponse curves. It was shown that the resistance due to solute concentration polarisation (R_cp) dominated the flux decline (40–74%). The fouling resistance (R_f) varied from 12 to 46%. To optimise simultaneously the three responses studied (R_f, R_cp and permeate limit flux), we applied the desirability function approach which allowed us to determine the best acceptable compromise. The selected UF conditions of the compromise were as follows: three bars, 0.95 L min^?1 and 30 °C. Optimal values of R_f, R_cp and permeate limit flux were equal to 18%, 72% and 19 L h^?1 m^?2, respectively.     

Use of a kaolinitic clay as a pozzolanic material for cements: Formulation of blended cement

Local kaolinitic clay (from the region of Tabarka, Tunisia) was tested as a pozzolanic material. Thermal treatments were performed as a means of activation of the minerals. The phase identification, before and after heat treatment, was studied by X-ray diffraction and differential thermal analysis/thermogravimetric analysis (DTA/TGA).

In order to check the effect of three variables (the calcination temperature, the specific surface of the calcined clay and the percentage of incorporation of the heat treated clay in the formula of the blended cement) on the compressive strength of blended cement mortar bars at 7, 28 and 91 days, a Box–Behnken design was set up. It was concluded that the mechanical properties of the blended cements were mainly governed by the percentage of incorporation and the fineness of the calcined clay. It was also demonstrated that increasing the fineness of the calcined clay allowed for increases in the level of cement substitution. Finally, a blended cement composition has been formulated, with optimal results at calcining temperature 700 °C, 30% of calcined clay ground at a Blaine fineness of 7700 cm²/g.     

Purification of wet process phosphoric acid by solvent extraction liquid-liquid equilibrium at 25 and 40°C of the system water-phosphoric acid-methylisobutylketone

Solubility and liquid-liquid phase equilibrium data are presented for the ternary system water-phosphoric acid-methyl isobutyl ketone at 25 and 40°C. Binodal curves, tie lines and distribution curves have been determined. Hand's method has been used to correlate tie lines and to calculate coordinates of plait points. The heterogeneous region at 40°C appeared to be slightly broader than that at 25°C, and the slopes of tie lines somewhat higher: the solubility of this system increases with decreasing temperature. The distribution curves indicated that methyl isobutyl ketone was an effective extractant for concentrated phosphoric acid solutions only.     

Statistical analysis of the removal of aluminum and magnesium impurities from wet-process phosphoric acid

The present paper relates to the treatment of crude wet-process phosphoric acid with ammonium nitrate and hydrofluoric acid to precipitate aluminum and magnesium impurities in the form of an easily separable phase: (NH₄)_xMg_yAl_z (F, OH)₆.2 H₂O. To check the effect of some concentration factors on this reaction, an orthogonal central composite design is realized with three variables: %Al³⁺, %NH₄⁺ and %F^?. It is concluded that the amount of aluminum in acid is the limiting factor of magnesium precipitation. Thus complete removal of magnesium, which is a major impurity in wet-process phosphoric acid, can be obtained by adding to the crude acid extra soluble aluminum salt simultaneously with hydrofluoric acid and ammonium nitrate.