Journal Articles

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12504/109

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Browsing Journal Articles by Author "Al-Khawlani, Amar"

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    Comparative analysis of polyester composites reinforced with local plant fibers: stipa tenacissima vs. agave americana
    (Journal of Natural Fibers, 2026-03-26) Meddah, Mostefa; Amroune, Salah; Rokbi, Mansour; Belaadi, Ahmed; Bouaziz, Nourelimane; Achour, Saber; Abdullah, Mahmood M. S; AlLohedan, Hamad A.; Al-Khawlani, Amar; Mukalazi, Herbert
    This work presents a comparative investigation of unsaturated polyester composites reinforced with two local Algerian lignocellulosic fibers: Stipa Tenacissima and Agave americana. These fibers were harvested, water-retted, and subsequently characterized using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD). Singlefiber tensile testing, supported by Weibull statistical analysis, showed that Stipa Tenacissima fibers exhibit a higher Young’s modulus (~15.5 GPa) and lower elongation at break, whereas Agave fibers display lower stiffness (~6.7 GPa) but significantly greater ductility. Two unidirectional composites, unsaturated polyester/ Stipa Tenacissima and unsaturated polyester/ Agave Americana, containing each approximately 25 wt% fiber were fabricated using the vacuum-bagging process and cured at 70 °C for 2 h. Mechanical testing revealed substantial improvements compared to neat polyester. Stipa Tenacissima fiber composites achieved an increase of about 120% in tensile modulus and nearly 110% in flexural modulus. In contrast, Agave Americana fiber composites exhibited lower stiffness but superior strain-to-failure and toughness, with an enhancement of ~95% in flexural strength. Overall, the results confirm that both Stipa Tenacissima and Agave Americana are effective reinforcements for polymeric matrices: Stipa Tenacissima fibers primarily improve stiffness and strength, while Agave fibers enhance ductility and energy-absorption capability.
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    Quality evaluation and predictive analysis of drilled holes in jute/ palm/polyester hybrid bio-composites using CMM and ANN techniques
    (Journal of Natural Fibers, 2025-04-26) Amroune, Salah; Elhadi, Abdelmalek; Slamani, Mohamed; Arslane, Mustapha; Belaadi, Ahmed; Abdullah, Mahmood M. S.; Al-Lohedan, Hamad A.; Bidi, Tarek; Mukalazi, Herbert; Al-Khawlani, Amar
    In this study, the evaluation of 75 holes drilled in a hybrid bio-composite jute/palm/polyester plate and controlled by a coordinate measuring machine (CMM) is essential to ensure the quality, dimensional precision, and geometric conformity of the plate. This rigorous process is necessary to meet industrial standards for circularity and cylindricity, which are essential criteria for high-performance applications. Additionally, the integration of artificial neural network (ANN) techniques has revolutionized this approach by enabling precise predictions of key parameters such as delamination, circularity, and cylindricity. In this study, the ANN was trained with 52 samples (70%), while 8 samples (10%) were used for validation and 15 others (20%) for testing at different stages. The results show the influence of feed rate on the delamination factor (Fd) (R2 = 0.98), circularity error (R2 = 0.99), and cylindricity error (R2 = 0.98). This predictive approach significantly improves the reliability and efficiency of the evaluation process.