University of Ouargla

Palm trees generate vast amounts of agricultural residue annually, yet only a tiny fraction is used. This work aims at analyzing the use of palm leaflet fibers as potential reinforcement in composite materials. The leaflets fibers are extracted from the date palm (DPLF) and from the Washingtonia palm (WPLF), which are abundant in all regions of Algeria. The morphology of the two types of leaflet fibers was examined by SEM and by FTIR, TGA, DSC, and XRD. Static tensile tests have shown a strong variation of the mechanical response along the length of the types of leaflets. For this reason, leaflets were then separated into distinct top, middle, and bottom parts. The more significant mechanical response was obtained for the top part of the leaflets. Date palm leaflet fibers exhibit 162

The rising prevalence of oxidative stress–related disorders, diabetes, and bacterial infections has driven the search for sustainable biomedical solutions. Developments in green technology have prompted researchers to explore low-cost, eco-friendly approaches for nanoparticle synthesis. This research presents a green strategy for synthesizing copper oxide nanoparticles (CuO NPs) using aqueous extracts of desert Ephedra alata and investigates their antioxidant, antidiabetic, and antibacterial properties. CuO NPs prepared from Ephedra alata extract were studied by UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDX) procedures, identifying an absorption peak at 340 nm, an average size of 28.81 nm, and a semi-spherical to irregular morphology. The DPPH and ABTS examinations assessed the antioxidant activity of copper oxide nanoparticles, revealing inhibition rates of 76.89 ± 0.11

The development of low-cost and sustainable adsorbents for cationic dye removal remains a significant challenge in wastewater treatment. In this study, raw peanut shells (RPS) were chemically activated using NaOH to produce alkali-activated peanut shells (APS) with enhanced surface and adsorption properties toward methylene blue dye. Alkali treatment induced a mass loss of 33.61

Wear is a critical issue in industrial systems, emerging not as an intrinsic material property but as a consequence of complex, interdependent factors. AA6061 aluminum alloy and AISI 1060 steel, widely employed in engineering applications, are particularly vulnerable to wear-induced degradation. This study presents an in-depth experimental investigation to elucidate the fundamental mechanisms governing tribological interactions. A novel wear-testing apparatus, fabricated via horizontal lathe machining, was utilized for dry and lubricated tribological assessments, with results benchmarked against conventional tribometer-based methodologies. The experimental matrix examined the effects of initial surface roughness, applied load (25-100 N), sliding velocity (0.30-0.50 m/s), and wear track diameter (4-10 mm) on contact temperature, volumetric wear loss, wear rate, and friction coefficient. Worn surfaces were analyzed using optical microscopy and SEM-EDS. Findings reveal that tribological responses are significantly influenced by morphological attributes and testing configurations, with nonlinear parameter interactions. A comparative analysis showed a 15.35 % relative error in wear rate between lathe-and tribometer-derived data, highlighting differences between controlled laboratory and real-world conditions. Microhardness profiling identified subsurface deformation regimes: AISI 1060 steel exhibited hardness reduction to approximate to 55 mu m depth before stabilization, whereas AA6061 displayed a rapid initial decline to 140 mu m, followed by gradual attenuation. This study underscores the potential for wear mitigation through parameter optimization and provides a methodological framework for extrapolating laboratory wear simulations to industrial environments, bridging the gap between academic research and practical engineering challenges. Verschlei ss ist ein kritisches Problem in industriellen Systemen, das nicht als intrinsische Materialeigenschaft auftritt, sondern als Folge komplexer, voneinander abh & auml;ngiger Faktoren. Die Aluminiumlegierung AA6061 und der Stahl AISI 1060, die in technischen Anwendungen weit verbreitet sind, sind besonders anf & auml;llig f & uuml;r verschlei ss bedingte Degradation. Diese Studie pr & auml;sentiert eine eingehende experimentelle Untersuchung zur Aufkl & auml;rung der grundlegenden Mechanismen, die tribologische Wechselwirkungen bestimmen. Ein neuartiges Verschlei ss pr & uuml;fger & auml;t, das mittels horizontaler Drehbearbeitung hergestellt wurde, wurde f & uuml;r trockene und geschmierte tribologische Bewertungen verwendet, wobei die Ergebnisse mit herk & ouml;mmlichen tribometerbasierten Methoden verglichen wurden. Die experimentelle Matrix untersuchte die Auswirkungen der anf & auml;nglichen Oberfl & auml;chenrauheit, der aufgebrachten Last (25-100 N), der Gleitgeschwindigkeit (0,30-0,50 m/s) und des Verschlei ss spurendurchmessers (4-10 mm) auf die Kontakttemperatur, den volumetrischen Verschlei ss verlust, die Verschlei ss rate und den Reibungskoeffizienten. Die verschlissenen Oberfl & auml;chen wurden mithilfe von Lichtmikroskopie und REM-EDX analysiert. Die Ergebnisse zeigen, dass tribologische Reaktionen erheblich von morphologischen Eigenschaften und Testkonfigurationen beeinflusst werden, wobei nichtlineare Parameterwechselwirkungen auftreten. Eine vergleichende Analyse ergab einen relativen Fehler von 15,35 % bei der Verschlei ss rate zwischen den mit der Drehmaschine und dem Tribometer gewonnenen Daten, was die Unterschiede zwischen kontrollierten Laborbedingungen und realen Bedingungen deutlich macht. Die Mikroh & auml;rtemessung identifizierte Verformungsbereiche unter der Oberfl & auml;che: AISI 1060-Stahl zeigte vor der Stabilisierung eine H & auml;rteverringerung bis zu einer Tiefe von approximate to 55 mu m, w & auml;hrend AA6061 einen raschen anf & auml;nglichen R & uuml;ckgang auf 140 mu m aufwies, gefolgt von einer allm & auml;hlichen Abschw & auml;chung. Diese Studie unterstreicht das Potenzial der Verschlei ss minderung durch Parameteroptimierung und bietet einen methodischen Rahmen f & uuml;r die Extrapolation von Verschlei ss simulationen aus dem Labor auf industrielle Umgebungen, wodurch die L & uuml;cke zwischen akademischer Forschung und praktischen technischen Herausforderungen geschlossen wird.

This study investigates the influence of rotational speed (1000–2000 rpm) on the microstructural evolution, crystallographic texture, recrystallization mechanisms, and microhardnessof dissimilar C45/E335 steel joints produced by rotary friction welding. Optical microscopy, energy-dispersive X-ray spectroscopy (EDS), electron backscatter diffraction (EBSD), and Vickers microhardness mapping were employed to establish quantitative process–structure–property relationships.Optical microscopy revealed that increasing rotational speed enhances interfacial mixing and promotes greater plastic deformation within the central weld zone. As rotational speed increases, the microstructure in this region becomes progressively refined and strain-affected.Hardness mapping demonstrated that the maximum hardness was consistently located in the thermo-mechanically affected zone (TMAZ), reaching 310 HV at 2000 rpm. In contrast, lower hardness values were measured in theheat-affected zones(HAZ), reflecting thermally induced recovery and grain coarsening. Notably, the region of maximum hardness shifts toward the C45 steel side, whereas the E335 steel exhibits a wider HAZ and lower local hardness. Furthermore, hardness increases with increasing rotational speed, indicating stronger deformation-induced strengthening at higher thermomechanical inputs.EBSD-based analyses of grain orientation spread (GOS), low-angle grain boundary fraction, and geometrically necessary dislocation density revealed microstructural and crystallographic gradients across the weld seam, including variations in grain size, low-angle grain boundary fraction, geometrically necessary dislocation density, and texture intensity. Therefore, microstructural evolution in the TMAZ is dominated by continuous dynamic recrystallization (CDRX), characterized by subgrain rotation, progressive LAGB formation, and relatively diffuse texture components. With increasing rotational speed, enhanced thermal input promotes grain boundary mobility and selective growth of strain-free grains, indicating a transition toward discontinuous dynamic recrystallization (DDRX), particularly in regions experiencing elevated temperatures and lower deformation such as the HAZ. This CDRX-to-DDRX shift is reflected by changes in GOS distributions, texture sharpening along the γ-fiber, and local variations in hardness.Overall, the results demonstrate that rotational speed governs the development of asymmetric thermomechanical gradients, which in turn control recrystallization behavior, texture evolution, and local microhardnesswithin the welded joint.