Analysis of plane and axisymmetric flows of incompressible fluids with the stream tube method: Numerical simulation by trust-region optimization algorithm

New concepts for the study of incompressible plane or axisymmetric flows are analysed by the stream tube method. Flows without eddies and pure vortex flows are considered in a transformed domain where the mapped streamlines are rectilinear or circular. The transformation between the physical domain and the computational domain is an unknown of the problem. In order to solve the non-linear set of relevant equations, we present a new algorithm based on a trust region technique which is effective for non-convex optimization problems. Experimental results show that the new algorithm is more robust compared to the Newton-Raphson method.     

Mechanical and physico-chemical characterization of cyclodextrin finished polyamide fibers

We present the study of the cyclodextrin (CDs) finishing of polyamide fibers (PA) by means of citric acid (CTR) as crosslinking agent. We observed that the mode of grafting happened by the formation of a crosslinked polymer formed between CTR and CDs. This polymer physically adhered to the fibers network and was resistant to hot water washings. Modified fibers were characterized by evaluating the contact angle with a polar liquid and by studying the hysteresis of damping of PA fibers (Cahn balance) with various grafting rates and by studying the absorptivity of grafted fabrics via the technique of the posed drop (Digidrop^® instrument). Then a mechanical characterization of the PA fabrics grafted with various proportions of CDs was accomplished, by traction and tear tests by using a tensile-test bench Lohmergy. Finally a topographic study of PA grafted surfaces was approached by atomic force microscopy (AFM and LFM; contact and non-contact mode) which permitted to evaluate the roughness and the chemical heterogeneity of the grafted surfaces.     

An Insight into All Tested Small Molecules against Fusarium oxysporum f. sp. Albedinis: A Comparative Review

Bayoud disease affects date palms in North Africa and the Middle East, and many researchers have used various methods to fight it. One of those methods is the chemical use of synthetic compounds, which raises questions centred around the compounds and common features used to prepare targeted molecules. In this review, 100 compounds of tested small molecules, collected from 2002 to 2022 in Web of Sciences, were divided into ten different classes against the main cause of Bayoud disease pathogen Fusarium oxysporum f. sp. albedinis (F.o.a.) with structure–activity relationship (SAR) interpretations for pharmacophore site predictions as (δ⁻···δ⁻), where 12 compounds are the most efficient (one compound from each group). The compounds, i.e., (Z)-1-(1.5-Dimethyl-1H-pyrazole-3-yl)-3-hydroxy but-2-en-1-one 7, (Z)-3-(phenyl)-1-(1,5-dimethyl-1H-pyrazole-3-yl)-3-hydroxyprop-2-en-1-one 23, (Z)-1-(1,5-Dimethyl-1H-pyrazole-3-yl)-3-hydroxy-3-(pyridine-2-yl)prop-2-en-1-one 29, and 2,3-bis-[(2-hydroxy-2-phenyl)ethenyl]-6-nitro-quinoxaline 61, have antifungal pharmacophore sites (δ⁻···δ⁻) in common in N1---O4, whereas other compounds have only one δ⁻ pharmacophore site pushed by the donor effect of the substituents on the phenyl rings. This specificity interferes in the biological activity against F.o.a. Further understanding of mechanistic drug–target interactions on this subject is currently underway.     

Physico-Chemical and Phytochemical Characterization of Moroccan Wild Jujube “Zizyphus lotus (L.)” Fruit Crude Extract and Fractions

Wild jujube “Ziziphus lotus (L.) Desf.” belongs to the Rhamnaceae family and is a traditionally herbaceous medicinal plant. It is very common in arid and semi-arid regions and is currently used for its antidiabetic, sedative, analgesic, anti-inflammatory and hypoglycemic activities. The aim of the present work was to characterize the physico-chemical properties and the phytochemical profile of wild jujube sample collected from the Guercif region, in order to determine the polyphenolic compounds and the antioxidant ability Analyses were carried out directly after the harvest for the determination of pH, refractive index, total soluble solid (°Brix), dry matter, sugar/acidity, total sugars, reducing sugars, as well as lipid and protein content. Results showed that the investigated fruit is acidic (pH 4.9 ± 0.23) and rich in sugars (80.2 g/100 g ± 3.81). The GC-MS analysis of the fruit revealed a number of volatile compounds, as many as 97, belonging to different chemical classes. The HPLC-DAD-ESI/MS analysis showed the presence of a total of 20 polyphenolic compounds in both EtOAc and MeOH-water extracts. Among them, p-Hydroxybenzoic acid was the most abundant in the EtOAc extract (185.68 µg/100 mg ± 0.5) whereas Quercetin 3-O-rhamnoside-7-O-glucoside was found in higher amounts in the MeOH-water extract (25.40 µg/100 mg ± 0.5). These components have medical interest, notably for human nutrition, as well as health benefits and therapeutic effects. Therefore, Moroccan jujube “Zizyphus lotus (L.)” fruit may have potential industrial applications for food formulations.     

Characterization of Phenolic Compounds,Vitamin E and Fatty Acids from Monovarietal Virgin Olive Oils of “Picholine marocaine” Cultivar

Olive oil is an important product in the Mediterranean diet, due to its health benefits and sensorial characteristics. Picholine marocaine is the most cultivated variety in Morocco. The present research aims to evaluate the phenolic compounds, vitamin E and fatty acids of commercial Picholine marocaine virgin olive oils (VOOs) from five different North Moroccan provinces (Chefchaouen, Taounate, Errachidia, Beni Mellal and Taza), using HPLC-photodiode array (PDA)/electrospray ionization (ESI)-MS, normal phase (NP)-HPLC/ fluorescence detector (FLD) and GC-flame ionization detector (FID)/MS, respectively. The obtained results showed an average content of 130.0 mg kg⁻¹ of secoiridoids (oleuropein aglycone, 10-hydroxy-oleuropein aglycone and ligstroside aglycone, oleocanthal and oleacein), 108.1 mg kg⁻¹ of phenolic alcohols (tyrosol and hydroxytyrosol), 34.7 mg kg⁻¹ of phenolic acids (caffeic acid, ferulic acid and elenolic acid), and 8.24 mg kg⁻¹ of flavonoids (luteolin, luteolin glucoside, apigenin). With regard to vitamin E, α-tocopherol was the most abundant vitamin E (57.9 mg kg⁻¹), followed by α-tocotrienol (2.5 mg kg⁻¹), γ-tocopherol (4.5 mg kg⁻¹) and β-tocopherol (1.9 mg kg⁻¹), while δ-tocopherol was not detected. Moreover, 14 fatty acids were found and, among them, oleic acid (76.1%), linoleic acid (8.1%) palmitic acid (8.7%) and stearic acid (2.5%) were the major fatty acids detected. Finally, heat map and principal component analysis allowed us to classify the studied provinces in terms of VOO chemical composition: Chefchaouen (tyrosol and hydroxytyrosol), Taounate (oleuropein aglycone), Errachidia (ferulic acid, w-3 and w-6), Beni Mellal (oleocanthal) and Taza (luteolin and oleic acid).     

Thermodynamic properties of the NdBr3–MBr binary systems (M = Na,K)

Thixoforming involves heating different types of alloys to the semisolid state at high heating rates and forming in die-casting machines or conventional presses. At temperatures higher than the solidus and lower than the liquidus, the mush metal behaves like a high-viscosity thixotropic material. Therefore, determining the thermodynamic behavior of the solid-to-liquid transition is paramount to control thixoforming processes. This article describes a simple, novel experimental setup based on differential thermal analysis (DTA) for analyzing the phase transitions in an alloy heated using high heating rates typical of industrial applications. A365 alloy was chosen to demonstrate the effectiveness of the method as the phase transformations for this alloy in semisolid materials (SSM) processing are well understood. Samples were heated to 750 °C using constant linear heating rates of 5, 10, 15, 20, 25, 50, 75, 100 and 125 °C min in a Norax 25 kW 8 kHz induction furnace with an Omron E5CK temperature controller. AISI 316 austenitic stainless steel was used as the inert reference. Comparison of the results of DTA using the proposed method and the results of simulation with Thermo-Calc^® indicates that the proposed in situ DTA device and its method is suitable for analyzing phase transitions when high heating rates are used.     

Electrochemical intercalation of O2− in CuAlO2 single crystal and photoelectrochemical properties

The delafossite CuAlO₂ single crystal, prepared by the flux method, is a low mobility p-type semiconductor with a hole mobility of 1.2 × 10⁻⁵ cm⁻² V⁻¹ s⁻¹. The chronoamperometry showed an electrochemical O²⁻ insertion with a diffusion coefficient D _303K of 3.3 × 10⁻¹⁸ cm² s⁻¹. The thermal variation of D in the range 293–353 K gave an enthalpy of diffusion (ΔH) of 44.7 kJ mol⁻¹. CuAlO₂ is photoactive, and the Mott–Schottky plot indicates a flat band potential of +0.42 V vs saturated calomel electrode and a holes density (N _A) of 10¹⁶ cm⁻³. The photocurrent spectra have been analyzed by using the Gartner model from which the absorption coefficients and diffusion lengths were determined. An optical transition at 1.66 eV, indirectly allowed, has been obtained. The spectral photoresponse provides a high absorption at 480 nm. The low quantum yield (η) is attributed to a small depletion length (440 nm) and a hole diffusion width (271 nm) compared to a very large penetration depth (12 μm).     

Convenient and easy access to 2-hydroxycyclopent-2-enones from acylcyanohydrins

A convenient access to 2-hydroxycyclopentenones was designed from acylcyanohydrins, by using titanacyclopropane complexes as nucleophilic partners and an intramolecular aldol condensation in basic conditions. The development of a one-pot procedure allows a step- and atom-economic process, and the use of Grignard reagents other than ethylmagnesium bromide provided valuable 3,4-disubstituted 2-hydroxycyclopentenones. The utility of the hydroxy group was illustrated by further functionalization of the α-position using palladium-mediated cross-coupling reactions.     

Microdroplet size prediction in microfluidic systems via artificial neural network modeling for water-in-oil emulsion formulation

In this paper, an experimental study and modeling by artificial neural networks were carried out to predict the generated microdroplet dimensionless size in a microfluidic system in order to formulate a water-in-oil emulsion. The various parameters that affect the size of microdroplets (flow rates, viscosities, surface tensions of both the two phases and the diameter of the microchannel) are studied and further grouped into dimensionless numbers; we used these numbers as input to the neural network and the dimensionless length as output. The better neural network architecture has 10 neurons in the hidden layer with a mean square error of 1.4 10^?6 and a determination’s coefficient near 1 value. The relative importance of inputs on the size of the microdroplets has been determined using the Garson algorithm and the results are in good agreement with other works.