• Energy Research

Abstract In the present work, the very low-cost glassy structured sodium silicate (Na2Si3O7) matrix has been reinforced with micro-and nano-sized silver (Ag) particles in different weight percentages. The ionizing radiation shielding performances of the micro and nano-structured composites have been determined experimentally and theoretically for the first time. The experiments have been realized by the gamma-ray spectroscopy setup equipped with NaI(Tl) detector and Ba-133 point radioactive source. The radiation shielding performance has been discussed in the context of mass attenuation coefficient ( μ / ρ ) half-value layer (HVL), and mean free path (MFP). Besides, the theoretical research related to the radiation shielding ability of the samples has been carried out by using the Monte Carlo N-Particle Transport (MCNP) v6.2© simulation code. Since the experimental values and MCNP findings are very close to each other, MCNP simulation has been extended to a large incoming photon energy interval ranging from 25 keV to 1000 keV for both micro-and nano-structured composites. The particle size effect (PSE) on radiation shielding performance has been investigated and discussed. As a result of PSE research, it has been revealed that the addition of nanoparticles is more effective in the improvement of the radiation shielding for the lowest Ag concentration and low photon energies. Additionally, the radiation shielding capability of the composites has been discussed in the context of ambient dose equivalent, H ∗ ( 10 ) which is one of the operational quantities. By using the ambient dose equivalent definition, the ambient dose rate values of the composites have been calculated for the first time. In conclusion, it has been determined the composites with higher micro-and nano-Ag particle additives have considerably good radiation shielding ability against low energy photons that are mostly utilized in diagnostic and treatment medical applications.

The rise in the utilization of radiation across various domains necessitates the advancement of next-generation radiation shielding materials that are devoid of lead. Due to their low weight and flexibility, polymer composites are considered as environmentally friendly alternative materials that can be used instead of toxic and high-weight lead for radiation shielding. From this point of view, the present study has focused on examining the radiation shielding performance of tantalum pentoxide doped high-density polyethylene (HDPE/Ta2O5) composites (including 5, 10, and 20 wt% Ta2O5) by using WinXCom software and MCNP6 simulation. The photon energies selected corresponded to the photons emitted from the Ba-133 (81 and 356 keV), Cs-137 (662 keV), and Co-60 (1173 and 1332 keV) radioactive sources that cover X-rays along with the low-and mid-energetic gamma-rays. The mass attenuation coefficient (/) of the composites has been calculated within the 81 keV-1332 keV photon range by utilizing WinXCom software and MCNP6 code. The other shielding parameters such as Half Value Layer (HVL), effective atomic number (Zeff), and effective electron density (Neff) have been determined. In the light of data, it has been revealed that gradual increase in Ta2O5 doping while improving the / coefficients, Zeff, and Neff parameters, decreasing the HVL length of HDPE considerably. Additionally, the parameters obtained by WinXCom and MCNP6 simulation are in good agreement. the. Ultimately, the best ionizing shielding performance among the composites has been determined for HDPE/20% Ta2O5 composite against 81 keV photons.

Abstract The role of BaO in the glassy structured Na2Si3O7 was investigated in the context of gamma radiations shielding parameters in the study. The mass attenuation coefficient, half layer value, and mean free path of the Na2Si3O7/BaO composites were calculated experimentally for the photons with the energies of 81 keV and 356 kev emitted from 133Ba point radioactive source. The same parameters were also calculated by Monte Carlo N-particle simulation (MCNP5) for the gamma photons which are emitted from 133Ba, 241Am, 99mTc, 177Lu, 192Ir, and 137Cs radioactive sources. The effective atomic number and effective electron density were determined by WinXCom software. Additionally, the scattered gamma photon intensity of the composites was realized for the energy of 364 keV and compared with the most utilized radiation shielding material lead. It was concluded that the composite having the highest BaO additive exhibits the best gamma photon absorption ability at all energies investigated.

© 2022 Elsevier LtdThe present study deals with the production of multifunctional polymer-based nanocomposites having the ability of ionizing radiation shielding and enhanced electric conductivity. In this context, it is aimed to obtain a new environmentally-friendly lead-free material with both high electric conductivity and ionizing radiation shielding features by reinforcing polycarbazole (PCz), a conductive polymer with BaO nanoparticles having a high effective atomic number. PCz matrix and BaO nanoparticles have been prepared by polymerization and co-precipitation methods, respectively. The surface morphology of the PCz matrix and nano BaO particles have been characterized by SEM and TEM images. Additionally, the optical band gaps of the samples have been calculated by using UV–visible spectroscopy. The lowest optical bandgap i.e. the highest electric conductivity has been observed for the 10 wt% BaO nanoparticle doped composite. On the other hand, the ionizing radiation shielding abilities of the samples have been evaluated in the context of mass attenuation coefficient, half-value layer, mean free path, effective atomic number, and effective electron density determined both experimentally and theoretically. Experimental measurements have been carried out by using NaI(Tl) detector and point radioactive sources (Ba-133, Cs-137, and Co-60) in the narrow beam geometry. The theoretical calculations have been performed by WinXCom software. A reasonable agreement between the experimental and WinXCom results has been found. Consequently, it has been determined that the maximum radiation shielding ability has been detected against 81 keV radiation for the PCz/30 wt% BaO nanocomposite. The composite has also a lower bandgap than pristine PCz. In this respect, the PCz/30 wt% BaO nanocomposite can have a promising potential in both medical and electronic applications that require high electric conductivity and ionizing radiation shielding ability.

Abstract The present study deals with determining the gamma-ray shielding parameters of the micro (μ)- Bi2O3, μ−WO3, nano (n)-Bi2O3, and n-WO3 reinforced Na2SiO3 (sodium metasilicate) composites experimentally and theoretically. The study has aimed to compare the size of reinforcing particles on the gamma-ray shielding ability of very low-cost and non-toxic Na2SiO3. In this context, the gamma-ray shielding performances of the samples containing different weight percentages of μ-Bi2O3, μ-WO3, n-Bi2O3, and n-WO3 particles have been evaluated by employing mass attenuation coefficient, half-value layer, and mean free path. The related parameters have been measured experimentally and also calculated by WinXCom. It has been revealed that Na2SiO3 composites having micro and nano-structured Bi2O3 and WO3 particles show good radiation shielding for 81 keV photons. In this respect, among all composites, the Na2SiO3/30% μ-WO3 sample has a promising potential to shield the ionizing radiation utilized in diagnostic imaging such as mammography, conventional X-ray machine, etc.

The thermal, mechanical and dielectric properties of Low Density Polyethylene/Polyaniline (LDPE/PANI) composites filled were investigated. LDPE/PANI composites were prepared using different weight percentage of PANI by compression molded in an electrically heated press. An objective of this study was to investigate dielectric and mechanical proprieties of LDPE/PANI composite films. The samples were characterized by Fourier-transform infrared spectroscopy analysis (FT-IR), tensile tests, thermogravimetry/differential thermogravimetry (TG/DTA) analysis and dielectric measurements. The FT-IR spectrum showed that PANI remained doped in the composite, and this improved the dielectric and mechanical proprieties of LDPE/PANI composite films. As compared to the mechanical and dielectric properties of pure LDPE, LDPE/0.7 wt% PANI composites have been found to have better mechanical and dielectric properties. The real (epsilon') and the imaginary parts (epsilon '') of the complex dielectric constant were measured in the frequency range of 100 Hz-10(6) Hz at room temperature (RT).

Abstract In the present study, welding area of 304 L stainless steel samples has been investigated with respect to photon interactions as means of linear attenuation coefficient ( μ ) , mass attenuation coefficient ( μ / ρ ) , half-value layer (HVL), tenth-value layer (TVL), effective atomic number (Zeff), electron density (Ne), energy absorption and exposure buildup factors for the first time. Five welded samples were irradiated by 241Am, 57Co, 133Ba, 137Cs and 60Co radioactive sources. The μ / ρ of samples were measured at 59.54, 122.01, 356.01, 661.66 and 1173.23 keV photon energies, and these coefficients were then used to determine Zeff and Ne using an interpolation method. Theoretical values of these parameters were also compared with the experimental values, and a good agreement has been obtained (relative difference (%) in Zeff ≤ 5.2%). Theoretical Zeff of 304 L was compared to the experimental Zeffs of welded steels to show differences between pure and welded 304Ls. It has been concluded that the welding process decreased radiation shielding capability when compared to pure 304 L stainless steel. Finally, energy absorption and exposure buildup factors of steels were calculated in the energy region 0.015–15 MeV, and significant differences between pure and welded 304Ls were obtained in the continuous energy region.

Abstract In this study, certain photon absorption parameters including the energy absorption buildup factor (EABF) and exposure buildup factor (EBF) have been investigated for three different basalt samples collected from different parts of Van city. Radiation shielding properties of the basalt samples indicated a strong correlation between photon energy absorption parameters and values of EABF and EBF of basalt samples. It was found that EABF and EBF parameters are related to radiation shielding properties of basalt samples. A new method and algorithm based on ZXCOM was used. Instead of calculating G – P fitting parameters for every effective atomic number ( Z e f f ), EABF and EBF were calculated for Z e f f by interpolation, using ANSI/ANS 6.4.3 standard data available for Z e f f .