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1.
Nanomaterials (Basel) ; 12(13)2022 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-35808005

RESUMO

Rock wool (RW) nanostructures of various sizes and morphologies were prepared using a combination of ball-mill and hydrothermal techniques, followed by an annealing process. Different tools were used to explore the morphologies, structures, chemical compositions and optical characteristics of the samples. The effect of initial particle size on the characteristics and photoelectrochemical performance of RW samples generated hydrothermally was investigated. As the starting particle size of ball-milled natural RW rises, the crystallite size of hydrothermally formed samples drops from 70.1 to 31.7 nm. Starting with larger ball-milled particle sizes, the nanoparticles consolidate and seamlessly combine to form a continuous surface with scattered spherical nanopores. Water splitting was used to generate photoelectrochemical hydrogen using the samples as photocatalysts. The number of hydrogen moles and conversion efficiencies were determined using amperometry and voltammetry experiments. When the monochromatic wavelength of light was increased from 307 to 460 nm for the manufactured RW>0.3 photocatalyst, the photocurrent density values decreased from 0.25 to 0.20 mA/mg. At 307 nm and +1 V, the value of the incoming photon-to-current efficiency was ~9.77%. Due to the stimulation of the H+ ion rate under the temperature impact, the Jph value increased by a factor of 5 when the temperature rose from 40 to 75 °C. As a result of this research, for the first time, a low-cost photoelectrochemical catalytic material is highlighted for effective hydrogen production from water splitting.

2.
Artigo em Inglês | MEDLINE | ID: mdl-35805783

RESUMO

The specific activity of U-238 and Th-232, as well as K-40 radionuclides, in twenty-nine investigated medicinal herbs used in Egypt has been measured using a high-purity germanium (HP Ge) detector. The measured values ranged from the BDL to 20.71 ± 1.52 with a mean of 7.25 ± 0.54 (Bq kg-1) for uranium-238, from the BDL to 29.35 ± 1.33 with a mean of 7.78 ± 0.633 (Bq kg-1) for thorium-232, and from 172 ± 5.85 to 1181.2 ± 25.5 with a mean of 471.4 ± 11.33 (Bq kg-1) for potassium-40. Individual herbs with the highest activity levels were found to be 20.71 ± 1.52 (Bq kg-1) for uranium-238 (H4, Thyme herb), 29.35 ± 1.33 (Bq kg-1) for thorium-232 (H20, Cinnamon), and 1181.2 ± 25.5 (Bq kg-1) for potassium-40 (H24, Worm-wood). (AACED) Ingestion-related effective doses over the course of a year of uranium-238 and thorium-232, as well as potassium-40 estimated from measured activity concentrations, are 0.002304 ± 0.00009 (minimum), 0.50869 ± 0.0002 (maximum), and 0.0373 ± 0.0004 (average)(mSv/yr). Radium equivalent activity (Raeq), annual gonadal dose equivalent (AGDE), absorbed gamma dose rate (Doutdoor, Dindoor), gamma representative level index (I), annual effective dose (AEDtotal), external and internal hazard index (Hex, Hin), and excess lifetime cancer risk were determined in medicinal plants (ELCR). The radiological hazards assessment revealed that the investigated plant species have natural radioactivity levels that are well within the internationally recommended limit. This is the first time that the natural radioactivity of therapeutic plants has been measured in Egypt. In addition, no artificial radionuclide (for example, 137Cs) was discovered in any of the samples. Therefore, the current findings are intended to serve as the foundation for establishing a standard safety and guideline for using these therapeutic plants in Egypt.


Assuntos
Plantas Medicinais , Monitoramento de Radiação , Radioatividade , Rádio (Elemento) , Poluentes Radioativos do Solo , Urânio , Radiação de Fundo , Radioisótopos de Césio , Radioisótopos de Potássio/análise , Rádio (Elemento)/análise , Poluentes Radioativos do Solo/análise , Tório/análise , Urânio/análise
3.
Nanomaterials (Basel) ; 11(7)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209698

RESUMO

(Tl2O3)30-(Li2O)10-(B2O3)(60-y)-(Sm2O3)y glass system with various Sm2O3 additives (y = 0, 0.2, 0.4, 0.6) was studied in detail. The vibrational modes of the (Tl2O3)30-(Li2O)10-(B2O3)(60-y) network were active at three composition-related IR spectral peaks that differed from those mixed with Samarium (III) oxide at high wavenumber ranges. These glass samples show that their permeability increased with the Samarium (III) oxide content increase. Additionally, the electronic transition between localized states was observed in the samples. The MAC, HVL, and Zeff values for radiation shielding parameters were calculated in the energy range of 0.015-15 MeV using the FLUKA algorithm. In addition, EBF, EABF, and ΣR values were also determined for the prepared glasses. These values indicated that the parameters for shielding (MAC, HVL, Zeff, EBF, EABF, and ΣR) are dependent upon the Samarium (III) oxide content. Furthermore, the addition of Samarium (III) oxide to the examined glass samples greatly reinforced their shielding capacity against gamma photon. The findings of the current study were compared to analyses of the XCOM software, some concretes, and lead. In the experiment, it was found that the SMG0.6 glass sample was the strongest shield.

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