Yazar "Salem, M. M." seçeneğine göre listele

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    Electrospun PVDF/Barium hexaferrite fiber composites for enhanced electromagnetic shielding in the X-band range
    (Elsevier, 2023) Salem, M. M.; Kenawy, El-Refaie; Zakaly, Hesham M. H.; Ene, Antoaneta; Azaam, Mohamed M.; Edries, Tarek B.; Zhou, Di
    In the contemporary, digitally-driven era, the prevalence of electronic devices has drastically escalated electromagnetic (EM) pollution levels, marking a significant environmental challenge. Electrospun fiber composites of polyvinylidene fluoride (PVDF) and Barium hexaferrite (BHF) were analyzed for their potential usage in X -band electromagnetic shielding applications (EMSAs). Pure PVDF and BHF-PVDF fiber composite were manufactured by needleless electrospinning. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and EM measurements utilizing a vector network analyzer (VNA) are all used to describe the prepared samples. The XRD and FTIR analyses confirmed the successful incorporation of BHF into the PVDF matrix. The results show that adding PVDF to BHF in fiber form enhances the reflection loss (RL), indicating improved electro-magnetic shielding effectiveness (EMSE). The SEM analysis revealed that the fiber composite had a uniform fiber diameter distribution. In contrast, the TGA analysis demonstrated good thermal stability of the fiber composite. Polymer samples were evaluated to enhance gamma radiation and neutron particle attenuation. MCNP5 and Phy-X/PSD software were used to study semi-crystalline fluorocarbon polymer (PVDF) and barium hex ferrite BaFe12O19 (30 wt%) with PVDF (70 wt%). The MCNP5 programme simulated 0.015-15 MeV radiation atten-uation. Additionally, the Phy-X/PSD programme verified the simulated mu values for the chosen Mxenes materials. The MCNP-5 code and Phy-X/PSD results were agreed. The linear attenuation coefficients for the polymer samples ranged from 3.166 to 0.032 cm2.g ? 1 for PVDF and from 73.960 to 0.113 cm2.g ? 1 for PVDF and BHF-PVDF Fiber at photon energies from 0.015 to 15 MeV. Overall, the electrospun fiber composite of PVDF and BHF particles shows promise for EMSAs in the X-band range. The enhanced RL observed in our study suggests that these fiber composites could be used to protect against electromagnetic radiation (EMR) from electronic devices, which is increasingly concerning in today's modern society.
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    Tailoring perovskite ceramics for improved structure, vibrational behaviors and radiation protection: The role of lanthanum in PbTiO3
    (Elsevier, 2024) Almousa, N.; Issa, Shams A. M.; Salem, M. M.; Darwish, Moustafa A.; Serag, Eman N.; Nazrin, S. N.; Zakaly, Hesham M. H.
    This study investigates the characteristics of lanthanum (La)-doped lead titanate (PbLaxTi(1-3x/4)O3 where, x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.1), a type of perovskite ceramic. It specifically focuses on analyzing its structure, vibrational properties, and efficacy in shielding against radiation. The prepared samples are investigated by X-ray diffraction (XRD), which clarified that the small doping of La (x <= 0.06) produced the required phase, and increasing the La doping (x > 0.06) produced nonrequired phases (secondary phase). Also, increasing the La doping converted the crystal symmetry from tetragonal to cubic, which was confirmed by the tetragonality raio (c/a) calculations. Also, the samples are investigated by Fourier transform infrared (FTIR) spectroscopy to confirm the XRD results. Transmission electron microscopy (TEM) examination clarified that the prepared samples were in the nanoscale range with a maximum crystallite size value of around 70 nm. In addition, the shielding effectiveness of all the prepared samples was theoretically evaluated using the Phy-X/PDS program by considering characteristics such as the linear attenuation coefficient (G(LAC)), mean free path (G(MFP)), transmission factor (TF), and radiation protection efficiency (RPE). Increasing the La concentration increases the theoretical density to 4.98 gm/cm3 at x = 0.1, leading to low TF and G(MFP) values and high G(LAC) values. This produces samples with high attenuation to radiation and high shielding effectiveness.