Search

This paper investigates numerically the bubble-type vortex breakdown apparition in the case of closed rotating flows of a viscous, axisymmetric, and incompressible fluid. First, a truncated conical/cylindrical cavity of spherical end disks is used to simulate and analyze the vortex structure under rigid surface conditions. The geometric effects of the enclosure are also studied. Vortex breakdown is demonstrated beyond the lower disk rotation rate threshold by introducing the no-slip condition imposed on the upper wall. The objective is to explore ways of controlling the evolution of this physical event by modifying the confinement conditions upstream of the vortex rupture. Particular attention is also paid to the effective kinematic viscosity, thermal diffusivity and geometric control of recirculation zones on the axis of rotation (axial bubble type). The second geometry consists of a spherical annulus formed by two concentric hemispheres in differential rotation under plat-free surface conditions. The results show that rotation of the inner hemisphere induces a vortex bubble on the polar axis. In contrast, the outer hemisphere rotation induces a toroidal vortex on the equator. [ABSTRACT FROM AUTHOR]

The amount of sewage sludge from wastewater treatment plants is continuously increasing and becoming a serious issue for environment. Therefore, the valorisation of sewage sludge in sectors such as the construction field where there is high demand for naturel resources would be great for the environment. The present work reports the possibility of using sewage sludge ash as substitute for part of cement in mortars. The cement was mixed at various percentages of sewage sludge ash: 0% (as control mortar), 10%, 20% and 30% of the cement's weight. Several properties have been tested at various curing ages (2, 7 and 28 days) and compared with control samples: mechanical properties including flexural and compressive strengths, and physical properties namely the dry bulk density, the water absorption and the apparent porosity. The obtained results have revealed that both physical and mechanical properties of mortar was influenced by the ratio of sewage sludge ash which can be used as a substitute of part of the cement in mortar. Flexural and compressive strengths increased over time for all the samples of mortar. The substitution can be as high as 30% while maintaining a compressive strength within the standard requirements at 28 days. Also the use of up to 30% of the weight of cement in sewage sludge ash provides lower dry bulk densities, higher both water absorption and higher apparent porosity than control mortars. [ABSTRACT FROM AUTHOR]

The present study evaluated the potential of Salvia balansae from the Aures Mountains as a source of natural bioactive compounds. Leaves, flowers, and stems were extracted separately using methanol, ethanol, and acetone. Phenolic compounds were quantified colorimetrically and identified using liquid chromatography coupled with mass spectrometry (LC-MS). Antioxidant capacity was assessed using six different in vitro assays, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 1,1-diphenyl-1-picrylhydrazyl, cupric reducing antioxidant capacity, ferric reducing antioxidant power, ferrous ion chelating, and phenanthroline assay, while the photo-protective capacity was evaluated using the sun protective factor. The methanolic flower extracts revealed the highest O-diphenol and phenolic levels (287.9 ± 0.50 and 147.87 ± 0.21 µg GAE/mg, respectively), whereas the acetonic and ethanolic leaf extracts contained the highest flavonoid (72.17 ± 0.12 μg QE/mg) and flavonol (35.28 ± 0.05 μg QE/mg) levels, respectively. LC-MS was used to identify 18 phenolics, including quinic acid (5.051–69.69 ppm), luteolin-7-o-glucoside (7.802–44.917 ppm), apigenin-7-o-glucoside (3.751–68.507 ppm), and cirsiliol (2.081–15.608 ppm), distinguishing this Aures taxon. Principal component analysis and unweighted pair-group method with arithmetic mean revealed variability in phytochemicals, antioxidant properties, and photo-protective activity influenced by biological activities and the compound content. Overall, S. balansae demonstrated promising photo-protective capacity, the presence of key bioactive compounds, and wide-ranging antioxidant potential, presenting this endemic plant as a valuable source of natural antioxidants and photo-protective agents with pharmaceutical and cosmetic applications.

This paper presents the vibration analysis of variable stiffness laminated composite (VSLC) elliptical plate by considering the curvilinear fibers. The problem is solved using the first-order shear deformation theory (FSDT) in conjunction with a curved trapezoidal p-element. The elements of the stiffness and mass matrices are determined analytically. The curved edges of the p-element are modeled accurately by the blending function method. A calculation code is developed to calculate the frequency parameters and the mode shapes, for different physical and mechanical parameters such as the fiber orientation angle, layup sequence, and boundary conditions. The obtained results show a good agreement with the existing solutions in the literature. New results for the natural frequencies of VSLC elliptical plate are offered. [ABSTRACT FROM AUTHOR]

This paper deals with the vibration analysis of variable stiffness composite laminated (VSCL) sandwich plates. The VSCL sandwich plate is composed by soft core and two laminated face sheets, in which the face sheets are considered with curvilinear fiber. The layer-wise plate theory and p-version of finite element method are used to solve the problem formulation. In layer-wise theory, each layer modeled separately as a one p-element and the continuity of displacement fields is based on a linear zig-zag variation of displacements through the thickness of the layers. The obtained results of present model are compared and validated with available solutions, such as equivalent single layer theories, layer-wise theory and three-dimensional theory for sandwich plate with constant stiffness. The frequencies and mode shapes are examined for different physical and mechanical parameters such as plate thickness, core to face sheets thickness ratio, orientation angle of curvilinear fibers, stacking sequence and boundary conditions. New layer-wise solutions for thin and thick VSCL sandwich plate are offered, in which can be used to establish benchmarks for future comparisons. [ABSTRACT FROM AUTHOR]

PurposeIn this study, we retrospectively reviewed the use of flow cytometry (FCM) in the diagnosis of inborn errors of immunity (IEIs) at a single center in Algeria. Sharing insights into our practical experience, we present FCM based diagnostic approaches adapted to different clinical scenarios.MethodsBetween May 2017 and February 2024, pediatric and adult patients presenting with clinical features suggestive of immunodeficiency were subjected to FCM evaluation, including lymphocyte subset analysis, detection of specific surface or intracellular proteins, and functional analysis of immune cells.ResultsOver a nearly seven-year period, our laboratory diagnosed a total of 670 patients (372 (55.5%) males and 298 (44.5%) females), distributed into 70 different IEIs belonging to 9 different categories of the International Union of Immunological Societies classification. FCM was used to diagnose and categorize IEI in 514 patients (76.7%). It provided direct diagnostic insights for IEIs such as severe combined immunodeficiency, Omenn syndrome, MHC class II deficiency, familial hemophagocytic lymphohistiocytosis, and CD55 deficiency. For certain IEIs, including hyper-IgE syndrome, STAT1-gain of function, autoimmune lymphoproliferative syndrome, and activated PI3K delta syndrome, FCM offered suggestive evidence, necessitating subsequent genetic testing for confirmation. Protein expression and functional assays played a crucial role in establishing definitive diagnoses for various disorders. To setup such diagnostic assays at high and reproducible quality, high level of expertise is required; in house reference values need to be determined and the parallel testing of healthy controls is highly recommended.ConclusionFlow cytometry has emerged as a highly valuable and cost-effective tool for diagnosing and studying most IEIs, particularly in low-income countries where access to genetic testing can be limited. FCM analysis could provide direct diagnostic insights for most common IEIs, offer clues to the underlying genetic defects, and/or aid in narrowing the list of putative genes to be analyzed.

Copyright of Phytothérapie is the property of John Libbey Eurotext Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The leather tannery industry produces a significant amount of solid chromium waste. Environmental concerns and escalating landfill costs are becoming increasingly serious problems to the leather industry and alternative disposal methods are needed. This research describes the possibility of decrease of the shrinkage temperature and to increase the pH value of leather waste by detoxification treatment with use of tartrate potassium. Through this investigation, we have established that is more possible to reduce the shrinkage temperature and neutralizing the acidity of this waste without his degradation or digestion and with decreasing of his chromium content about 95%. The use of reaction time of 72 h generates the optimal decreasing of the shrinkage temperature of waste leather about 42[degrees]C close to the one of hide at native state (before tanning process) which reveal another ecological and simple way for the treatment of the chromium containing leather waste. Key words: Chromium, waste leather, pollution, decontamination, shrinkage temperature, INTRODUCTION The production of chromium containing solid wastes in leather industry has been recognized as a real problem for many years (1), (2) Using chromium as basic chemical substance in [...]

The p-version of the finite element method based on the first-order shear deformation theory (FSDT) is applied, to the free vibration of symmetric variable stiffness composite laminated (VSCL) elliptical plates, with curvilinear fibers. A curved hierarchical rectangular finite element is developed and used to model the elliptical plate. The geometry is described accurately by the blending function method. The element stiffness and mass matrices are integrated numerically using the Gauss-Legendre quadrature. The equations of motion are derived employing Lagrange's method. The numerical results are validated by means of convergence tests and compared with available data in the literature, for isotropic and constant stiffness composite laminated (CSCL) circular and elliptical plates. The contour plots of the fundamental frequency as a function of the fiber orientation angles are presented for clamped and soft simply supported symmetric VSCL elliptical plates. The effect of thickness ratio, aspect ratio, boundary conditions, and mechanical parameters on the frequencies of the lowest five modes is investigated and discussed. The mode shapes are examined by considering the effect of the fiber orientation angles and stacking sequences. [ABSTRACT FROM AUTHOR]

This paper presents the free vibration analysis of a composite laminated and sandwich square plate with circular cutout. The problem formulation is based on the higher order shear deformation plate theory HDST C0 coupled with a curved quadrilateral p-element. The elements of the stiffness and mass matrices are calculated analytically. The curved edges are accurately represented using the blending function method. A calculation program is developed to determine the fundamental frequencies for different physical and mechanical parameters such as the cutout size and location, plate thickness, fiber orientation angle and boundary conditions. The results obtained show a good agreement with the available solutions in the literature. New results for the fundamentals frequencies of composite laminated and sandwich plates with circular cutout are presented. [ABSTRACT FROM AUTHOR]

This work aims to explore the use of alfa fibers as a natural and low-cost adsorbent for the removal of astrazon yellow dye (AY) from aqueous solution on industrial textile effluent. The alkaline procedure was used to remove none cellulosic substances such as pectin, lignin and hemicellulose. The influence of alkaline treatment on fiber morphology is analyzed by FT-IR and SEM, showing physico-chemical changes in the treated material. The observations show that an interesting mesoporous structure was developed. The specific surface was notably increased to 62.48 m2/g. Batch adsorption experiments, at 25 C° and agitation speed of 150 rpm, were carried out and the effects of operational parameters including contact time, initial dye concentration, adsorbent dose, and pH solution on adsorbed amount were investigated and discussed. Batch adsorption shows that equilibrium was obtained after 40 min, and the adsorbed dye amount increases with pH. The highest removal rate was about 83 %. The experimental data of modelization showed that data were best fitted with the Freundlich model. The correlation coefficient values (R2) showed that the adsorptions Kinetic were well described by the pseudo-second-order model. The adsorption thermodynamics and isotherms are consistent with spontaneous endothermic physicosorption. The results indicated that alfa fibers could be used effectively and advantageously to adsorb astrazon yellow dye from aqueous solutions. [ABSTRACT FROM AUTHOR]