In this work, black nanocarbon-loaded 0–100 parts-per-hundred (phr) PbO-filled acrylonitrile butadiene rubber (NBR)/styrene-butadiene rubber (SBR) blend composites were prepared by using an ordinary standard rubber mixer. Both mechanical and gamma attenuation properties of the prepared samples were investigated. Maximum tensile strength and elongation at break were obtained at 40 phr PbO concentration. The obtained values for the mass attenuation coefficient with the increased PbO concentration from 0–100 phr ranged from 0.12–0.22 cm2/g at 0.239 MeV. Scanning electron microscope (SEM) with the elemental mapping analysis results showed high homogeneity at 40 phr of the prepared rubber composites, with some areas of elemental agglomeration at a high concentration of lead oxide. The obtained results highly recommend the use of the prepared nanocarbon-reinforced PbO/NBR/SBR blend compared to those previously used as personal protective equipment in radiation-shielding applications.
In this study, both radiation shielding capability and optical properties of prepared SiO2-ZnO-Na2CO3-H3BO3-BaCO3 glass composite with different concentrations of barium carbonate (0–30 mol%) have been studied. Gamma attenuation properties, such as the mass attenuation coefficient (MAC), mean free path (MFP), and exposure build-up factor (EBF), are experimentally and theoretically investigated. The detected XRD patterns for the prepared glass composites confirm their amorphous nature. It is evident from the obtained data that all tested parameters, such as mass density, molar volume, refractive index, dielectric constant, refraction loss (%), and molar refraction, have been increased as BaCO3 mol% increased. At the same time, the results of the optical bandgap show a gradual decrease with increasing barium concentration. It was also found that the mass attenuation coefficients increased with BaCO3 concentration from 0.078 at zero mol% BaCO3 to 0.083 cm2/g at 30 mol%. Moreover, the half-value layer (HVL) and the exposure build-up factor (EBF) up to 40 mfp penetration depth were investigated in addition to the effective atomic number (Zeff) and the corresponding equivalent atomic number (Zeq) at the energy range of 0.015–15 MeV. The produced glass composite might be considered for many shielding applications based on the obtained results that require a transparent shielding material.
In targeted therapy, clusters of drug carriers (nanoparticles and microparticles) could be in contact with a surface such as the lumen of blood vessels and the interior of the gastrointestinal tract. We study the motion characteristics of clusters of microparticles when they slide on a surface under the influence of weak oscillating magnetic fields (less than 11 mT). The oscillating magnetic fields exert a magnetic torque on the microparticles and allow them to oscillate, and hence overcome the static friction and slide on a surface. We characterize the frequency response of clusters of microparticles by applying oscillating magnetic fields with a frequency range of 0 Hz to 55 Hz, in the presence of a constant magnetic field gradient (0.9 T/m). Clusters of 3 to 4 and 5 to 9 microparticles achieve maximum sliding speeds of 1100 µm/s and 1150 µm/s, at oscillating magnetic fields of 30 Hz. In addition, we experimentally demonstrate closed-loop motion control of the clusters with maximum position error of 20 µm. Furthermore, we show that the magnetic field gradient required to drive a cluster of microparticles (with 3 to 4 microparticles) decreases by 75% in the presence of oscillating magnetic fields from 5 Hz to 50 Hz.
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