Influence of Increasing SnO2 Content on the Mechanical, Optical, and Gamma-Ray Shielding Characteristics of a Lithium Zinc Borate Glass System

A series of six samples were prepared based on the chemical composition of 65B2O3 + 20ZnO + (15-x)LiF + xSnO2 (where x = 0, 0.25, 0.5, 0.75, 1, and 1.25 mol%) to study the role of SnO2 on enhancing the optical and radiation attenuation capacity of the prepared glasses. The preparation of the glass series was performed using the melt quenching method at 1100 °C for 60 min. The density of the fabricated samples was measured using an MH-300A densimeter. The optical parameters of the fabricated glasses were calculated based on the spectrum recorded by a Cary 5000 UV–Vis–NIR double beam spectrophotometer in a wavelength range of 200 to 3000 nm. Furthermore, Monte Carlo simulation code and the XCOM online database were used to estimate the gamma-ray shielding capacity of the fabricated samples from 0.244 to 2.506 MeV. The results show enhanced gamma-ray shielding capacity due to the replacement of LiF by SnO2. The linear attenuation coefficient at 0.244 MeV was enhanced from 0.352 to 0.389 cm−1. The half-value thickness of the investigated glasses decreased from 1.967 to 1.784 cm when the increasing addition of SnO2 from 0 to 1.25 mol%. © 2022, The Author(s).The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project (PNURSP2022R2), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Characterization and Gamma-ray Shielding Performance of Calcinated and Ball-Milled Calcinated Bentonite Clay Nanoparticles

The current investigation deals with the fabrication of two various composite-based bentonite clay minerals. The characterization and radiation shielding parameters for the two fabricated composites (calcinated and ball-milled calcinated bentonite) were studied. X-ray diffraction was utilized to illustrate the crystalline phase of the fabricated composites. Furthermore, Williamson and Hall’s method was used to determine the grain size of both the calcinated and ball-milled calcinated composites. The particle size, according to the calculation was 39.84 nm, and the strain was 0.216 for the calcinated bentonite, while the particle size of the ball-milled bentonite was 26.96 nm, and the strain was 0.219. In comparison, the transmission electron microscope (TEM) showed that the grain size of the calcinated bentonite was 566.59 nm, and it was 296.21 nm for the ball-milled calcinated bentonite. The density of the fabricated composites varied between 1.60 and 186 g/cm3 for the calcinated bentonite and between 1.83 and 2.075 g/cm3 for the ball-milled calcinated bentonite. Moreover, the radiation shielding capacity of the composites was analyzed. The results show that the gamma-ray attenuation capacity of ball-milled calcinated bentonite is high compared to ordinary calcinated bentonite. These results confirm the effect of particle grain size on optimizing the gamma-ray shielding capacity of the fabricated materials. © 2022 by the authors.Princess Nourah Bint Abdulrahman University, PNU: PNURSP2022R57The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R57), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Evaluation of the Radiation-Protective Properties of Bi (Pb)–Sr–Ca–Cu–O Ceramic Prepared at Different Temperatures with Silver Inclusion

The influences of the sintering process and AgNO3 addition on the phase formation and radiation shielding characteristics of Bi1.6Pb0.4Sr2Ca2Cu3O10 were studied. Three ceramics (code: C0, C1, and C2) were prepared as follows: C0 was obtained after calcination and only one sintering step, C1 was obtained after calcination and two sintering cycles, and C2 was prepared after the addition of AgNO3 at the beginning of the final sintering stage. C2 displayed the maximum volume fraction of the Bi-2223 phase (76.4 vol%), the greatest crystallite size, and high density. The linear mass attenuation coefficient (µ) has been simulated using the Monte Carlo simulation. The µ values are high at 15 keV (257.2 cm−1 for C0, 417.57 cm−1 for C1, and 421.16 cm−1 for C2), and these values dropped and became 72.58, 117.83 and 133.19 cm−1 at 30 keV. The µ value for the ceramics after sintering is much higher than the ceramic before sintering. In addition, the µ value for C2 is higher than that of C1, suggesting that the AgNO3 improves the radiation attenuation performance for the fabricated ceramics. It was demonstrated that the sintering and AgNO3 addition have a considerable influence on the ceramic thickness required to attenuate the radiation. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project (PNURSP2022R2), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

The Influence of Titanium Dioxide on Silicate-Based Glasses: An Evaluation of the Mechanical and Radiation Shielding Properties

The mechanical and radiation shielding features were reported for a quaternary Na2 O-CaO-SiO2-TiO2 glass system used in radiation protection. The fundamentals of the Makishima– Mazinize model were applied to evaluate the elastic moduli of the glass samples. The elastic moduli, dissociation energy, and packing density increased as TiO2 increased. The glasses’ dissociation energy increased from 62.82 to 65.33 kJ/cm3, while the packing factor slightly increased between 12.97 and 13.00 as the TiO2 content increased. The MCNP-5 code was used to evaluate the gamma-ray shielding properties. The best linear attenuation coefficient was achieved for glass samples with a TiO2 content of 9 mol%: the coefficient decreased from 5.20 to 0.14 cm−1 as the photon energy increased from 0.015 to 15 MeV. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-Track Research Funding Program

The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte‐Carlo Simulation and Theoretical Study

The radiation shielding competence was examined for a binary glass system xLa2O3 + (1 − x) TeO2 where x = 5, 7, 10, 15, and 20 mol% using MCNP‐5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Zeq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast‐track Research Funding Program to support publication in the top journal (Grant No. 42‐FTTJ‐77)

Influence of Li2O Incrementation on Mechanical and Gamma-Ray Shielding Characteristics of a TeO2-As2O3-B2O3 Glass System

According to the Makishema–Mackenzie model assumption, the dissociation energy and packing density for a quaternary TeO2-As2O3-B2O3-Li2O glass system were evaluated. The dissociation energy rose from 67.07 to 71.85 kJ/cm3, whereas the packing factor decreased from 16.55 to 15.21 cm3/mol associated with the replacement of TeO2 by LiO2 compounds. Thus, as a result, the elastic moduli (longitudinal, shear, Young, and bulk) were enhanced by increasing the LiO2 insertion. Based on the estimated elastic moduli, mechanical properties such as the Poisson ratio, microhard-ness, longitudinal velocity, shear velocity, and softening temperature were evaluated for the investigated glass samples. In order to evaluate the studied glasses’ gamma-ray shield capacity, the MCNP-5 code, as well as a theoretical Phy-X/PSD program, were applied. The best shielding capacity was achieved for the glass system containing 25 mol% of TeO2, while the lowest ability was obtained for the glass sample with a TeO2 concentration of 5 mol%. Furthermore, a correlation between the studied glasses’ microhardness and linear attenuation coefficient was performed versus the LiO2 concentration to select the glass sample which possesses a suitable mechanical and shielding capacity. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This research was funded by the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding Program to support publication in a top journal (Grant no. 42-FTTJ-67)

Structural and Magnetic Phase Transitions in BiFe1−x_{1−x}Mnx_xO3_3 Solid Solution Driven by Temperature

The crystal structure and magnetic state of the (1 − x)BiFeO$_3$-(x)BiMnO$_3$ solid solution has been analyzed by X-ray diffraction using lab-based and synchrotron radiation facilities, magnetization measurements, differential thermal analysis, and differential scanning calorimetry. Dopant concentration increases lead to the room-temperature structural transitions from the polar-active rhombohedral phase to the antipolar orthorhombic phase, and then to the monoclinic phase accompanied by the formation of two-phase regions consisting of the adjacent structural phases in the concentration ranges 0.25 < x$_1$ < 0.30 and 0.50 ≤ x$_2$ < 0.65, respectively. The accompanied changes in the magnetic structure refer to the magnetic transitions from the modulated antiferromagnetic structure to the non-colinear antiferromagnetic structure, and then to the orbitally ordered ferromagnetic structure. The compounds with a two-phase structural state at room temperature are characterized by irreversible temperature-driven structural transitions, which favor the stabilization of high-temperature structural phases. The magnetic structure of the compounds also exhibits an irreversible temperature-induced transition, resulting in an increase of the contribution from the magnetic phase associated with the high-temperature structural phase. The relationship between the structural parameters and the magnetic state of the compounds with a metastable structure is studied and discussed depending on the chemical composition and heating prehistory

A novel barium oxide-based Iraqi sand glass to attenuate the low gamma-ray energies: Fabrication, mechanical, and radiation protection capacity evaluation

In the present work, untreated Iraqi sand with grain sizes varied between 100 and 200 μm was used to produce a colored glass sample that has shielding features against the low gamma-ray energy. Therefore, a weight of 70–60 wt % sand was mixed with 9–14 wt% B2O3, 8–10 wt% Na2O, 4–6 wt% of CaO, 3–6 wt% Al2O3, in addition to 0.3% of Co2O3. After melting and annealing the glass sample, the X-ray diffraction spectrometry was applied to affirm the amorphous phase of the fabricated glass samples. Moreover, the X-ray dispersive energy spectrometry was used to measure the chemical composition, and the MH-300A densimeter was applied to measure the fabricated sample's density. The Makishima-Makinzie model was applied to predict the mechanical properties of the fabricated glass. Besides, the Monte Carlo simulation was used to estimate the fabricated glass sample's radiation shielding capacity in the low-energy region between 22.1 and 160.6 keV. Therefore, the simulated linear attenuation coefficient changed between 10.725 and 0.484 cm−1, raising the gamma-ray energy between 22.1 and 160.6 keV. Also, other shielding parameters such as a half-value layer, pure lead equivalent thickness, and buildup factors were calculated. © 2022 Korean Nuclear SocietyPrincess Nourah Bint Abdulrahman University, PNU: PNURSP2022R28The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R28), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Design and Gamma-Ray Attenuation Features of New Concrete Materials for Low- and Moderate-Photons Energy Protection Applications

We aimed, in this investigation, to prepare novel concretes which can be used in gamma-ray shielding applications. The experimental approach was performed using a NaI (Tl) detector to measure the concrete’s shielding features for different energies, ranging from 0.081 MeV to 1.408 MeV. The density of the fabricated concretes decreased with increasing W/C ratio, where the density decreased by 2.680 g/cm3, 2.614 g/cm3, and 2.564 g/cm3 for concretes A, B, and C, respectively, with increases in the W/C ratio of 0.4, 0.6, and 0.8, respectively. When the energy was elevated between 0.08 MeV and 1.408 MeV, the highest values were attained for concrete A, with values ranging between 0.451 cm−1 and 0.179 cm−1. The lowest half-value layer (Δ0.5) values were achieved for concrete C, where the Δ0.5 values varied between 1.53 cm and 3.86 cm between 0.08 MeV and 1.408 MeV. The highest Δ0.5 values were achieved for concrete A, where the Δ0.5 varied between 1.77 cm and 4.67 cm between 0.08 MeV and 1.408 MeV. According to this investigation, concrete A has the highest promise in radiation shielding purposes because it has the most desirable properties of the concretes studied. © 2022 by the authors.Princess Nourah Bint Abdulrahman University, PNU: PNURSP2022R57The authors express their gratitude to Princess Nourah bint Abdulrahman University Researchers Supporting Project number (PNURSP2022R57), Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia

Structural insights in cell-type specific evolution of intra-host diversity by SARS-CoV-2

As the global burden of SARS-CoV-2 infections escalates, so does the evolution of viral variants with increased transmissibility and pathology. In addition to this entrenched diversity, RNA viruses can also display genetic diversity within single infected hosts with co-existing viral variants evolving differently in distinct cell types. The BriSΔ variant, originally identified as a viral subpopulation from SARS-CoV-2 isolate hCoV-19/England/02/2020, comprises in the spike an eight amino-acid deletion encompassing a furin recognition motif and S1/S2 cleavage site. We elucidate the structure, function and molecular dynamics of this spike providing mechanistic insight into how the deletion correlates to viral cell tropism, ACE2 receptor binding and infectivity of this SARS-CoV-2 variant. Our results reveal long-range allosteric communication between functional domains that differ in the wild-type and the deletion variant and support a view of SARS-CoV-2 probing multiple evolutionary trajectories in distinct cell types within the same infected host