Microstructure investigation, Electrical properties, and γ-rays' protection capacity for ZnO doped clay ceramic.

A series of ceramic samples fabricated based on ZnO doped different concentrations of natural clay according to the relation (1-x) ZnO - (x) clay; 5 wt% ≤ x ≤ 20 wt%. The samples were pressed and sintered at 1200 °C. The experimental techniques were used to characterize and measure the chemical composition, density, and current-voltage measurements for the fabricated ceramics samples. The measurements depict an increase in the I-V nonlinearity with raising the clay concentration, where the increase in clay by up to 20 wt% shifts breakdown voltage to a higher value of up to 390 V/cm and decreases leakage current to 55 mA/cm2. The examinations for the gamma-ray shielding capacity for the fabricated composites (utilizing Monte Carlo simulation) demonstrate enrichment of clay concentration between 5 wt% and 20 wt% reduced the linear attenuation coefficient for the fabricated ceramics by 23.15% and 8.66% at γ photon energy of 0.059 MeV and 1.252 MeV, respectively. The half-value thickness and lead's equivalent thickness increased along with a drop in the linear attenuation coefficient, but the radiation protection effectiveness of the fabricated ceramics increased.

An extensive assessment of the impacts of BaO on the mechanical and gamma-ray attenuation properties of lead borosilicate glass.

The current work deals with the synthesis of a new glass series with a chemical formula of 5Al2O3-25PbO-10SiO2-(60-x) B2O3-xBaO; x was represented as 5, 10, 15, and 20 mol%. The FT-IR spectroscopy was used to present the structural modification by rising the BaO concentration within the synthesized glasses. Furthermore, the impacts of BaO substitution for B2O3 on the fabricated borosilicate glasses were investigated using the Makishima-Mackenzie model. Besides, the role of BaO in enhancing the gamma-ray shielding properties of the fabricated boro-silicate glasses was examined utilizing the Monte Carlo simulation. The mechanical properties evaluation depicts a reduction in the mechanical moduli (Young, bulk, shear, and longitudinal) by the rising of the Ba/B ratio in the fabricated glasses. Simultaneously, the micro-hardness boro-silicate glasses was reduced from 4.49 to 4.12 GPa by increasing the Ba2+/B3+ ratio from 0.58 to 3.18, respectively. In contrast, the increase in the Ba/B ratio increases the linear attenuation coefficient, where it is enhanced between 0.409 and 0.448 cm-1 by rising the Ba2+/B3+ ratio from 0.58 to 3.18, respectively. The enhancement in linear attenuation coefficient decreases the half-value thickness from 1.69 to 1.55 cm and the equivalent thickness of lead is also reduced from 3.04 to 2.78 cm, at a gamma-ray energy of 0.662 MeV. The study shows that the increase in the Ba2+/B3+ ratio enhances the radiation shielding capacity of the fabricated glasses however, it slightly degrades the mechanical properties of the fabricated glasses. Therefore, glasses with high ratios of Ba2+/B3+ have high gamma-ray shielding ability to be used in hospitals as a shielding material.

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.

Examinations the optical, mechanical, and shielding properties of Ag2O doped B2O3-Bi2O3-SrF2-Na2O glasses for gamma ray shield applications.

A series of five glass samples have a chemical composition of (55-x) B2O3 + 5 Bi2O3 + 20SrF2 + 20Na2O + xAg2O with varied doping ratios x = 0, 1, 2, 3, and 4 mol% were fabricated using the melt quenching technique to study the effect of B2O3 replacement by Ag2O on the physical, mechanical, optical and gamma-ray shielding capacity of the fabricated glasses. The Cary 5000 UV-Vis-NIR measured the optical absorption in the wavelength range between 200 and 3000 nm. Based on the measured optical absorption, energy (direct/indirect) bandgap and Urbach energy were calculated. Moreover, the measured samples density, molar volume, packing density, dissociation energy, and mechanical properties for the fabricated glasses were calculated using the concepts of the Makishima-Mackenzie model. In this regard, the microhardness was decreased from 4.070 to 3.931 GPa with raising the Ag2O concentration. The effect of B2O3 replacement on the shielding capacity was also evaluated using the Monte Carlo simulation. The simulation results showed that the replacement of B2O3 causes a significant increase in the shielding parameters like linear attenuation coefficient and radiation shielding capacity. The best radiation shielding properties were achieved for a glass sample with 4 mol% Ag2O compound. Its linear attenuation coefficient varied between 8.091 and 0.134 cm-1, raising the gamma photon energy between 0.059 and 2.506 MeV.

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%.

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.

Influence of Methomyl (Copter 90%) on certain biochemical activities and histological structures of land snails Monacha cartusiana.

This manuscript was conducted to spotlight the toxic effect of two sub-lethal concentrations of Methomyl (Copter) LC20 (0.075 g/L) and LC40 (0.180 g/L) on some biochemical parameters and histological alterations for land snail Monacha Cartusiana (Muller, 1774). Land snails belong to the class Gastropoda and Phylum Mollusca. This study cleared that both the used concentrations (of Copter) caused a significant increase for activities of three enzymes: alkaline phosphatase (ALP), alanine amino transaminase (ALT), and Aspartate amino transaminase (AST) after 24, 48, and 72 h from exposure starting. In contrast, a total protein (TP) activity decreased at exposure for two concentrations at all lethality periods. Both concentrations of Copter (0.0.75 g/L and 0.180 g/L) have shown histological changes for land snail tissues after 96 h of exposure; digestive gland, hermaphrodite gland, foot, and mantle. Degeneration, rupture, and vacuolization for digestive cells have been shown; furthermore, hemolytic infiltration in connective tissue will be recognized for the digestive gland. The Oocyte and sperm show degenerated with deformation in the connective tissue of the hermaphrodite gland. Likewise, deformation in the muscle fiber layer of the foot in the land snail distorts the epidermis and mucus gland suffering from necrosis. Moreover, mantle shows rapture in epidermis layer, deformed in muscle fiber layer, and vacuolization and necrosis take place in mucus gland.

Biogenic synthesis of CuO-NPs as nanotherapeutics approaches to overcome multidrug-resistant Staphylococcus aureus (MDRSA).

Due to the misuse of antibiotics, the multidrug-resistant Staphylococcus aureus (MDRSA) has caused serious infections and become more difficult to deal with. Here we propose to synthesise copper oxide nanoparticles (CuO-NPs) using a cell-free filter of Streptomyces rochei to enhance antibiotics activity against (MDRSA) and kill them. Characterisation of CuO-NPs using ultraviolet, dynamic light scattering, zeta potential, transmission electron microscopic (TEM), and X-ray diffraction, were investigated. The antibacterial action of the CuO-NPs was tested against standard strain and clinical isolates using the agar well diffusion method and the microdilution assay. The results showed the monodispersed spherical shape CuO-NPs with a mean diameter of 10.7 nm and were found to be active against (MDRSA). By a combination of CuO-NPs with different antibiotics, the highest synergistic effect was observed with cefoxitin, the minimum inhibitory concentration (MIC) was reduced to 6.5 for CuO-NPs, and 19.5 for cefoxitin. Time-kill assay showed the highest reduction in log10 colony-forming unit (CFU)/ml of initial inoculum of MRSA after 24 h. The HFB-4 cells cultured in the presence of CuO-NPs showed normal morphology with 100% viability at 8 µg/ml. TEM showed that combination (1/4 MIC cefoxitin +1/16 MIC CuO-NPs) highly damages bacterial cells' shape. The biosynthesis CuO-NPs showed antibacterial activity against S. aureus suggesting a promising alternative in clinical.

Impact of Bi2O3 modifier concentration on barium-zincborate glasses: physical, structural, elastic, and radiation-shielding properties.

ABSTRACT: A sequence of Bi2O3 varying barium-zincborate (BZX) glasses with the chemical composition (60-x) B2O3-20ZnO-20BaCO3-xBi2O3-0.5Dy2O3 (where x = 0, 5, 10, 15, 20, 25, and 30 in wt%) is fabricated by melt-quenching method. The fabricated samples were examined for the variation in physical, structural, elastic, and radiation-shielding properties with the Bi2O3 concentration. The structural and compositional evaluations are done using XRD and FTIR spectra. The BZX matrixes consist of the trigonal-planar and tetrahedral groups of borates, BiO3 and BiO6 units of Bi2O3, and the non-bridging oxygen in general. The average single-bond strength values substantiate the increasing ionic nature of the BZX glasses. The variation in the density and molar volume of the BZX series discussed in terms of various structural and elastic properties. The glass-coded BZ15 was found to be the best candidate for the sound-resistant applications based on the atomic packing fraction and the acoustic impedance studies. With MCNP5 simulation, the mass attenuation coefficient (MAC) values of all the samples were calculated and compared with a theoretical approach using the XCOM program. As the amount of Bi2O3 increases, the linear attenuation coefficient (LAC) increases with it at all energies. The LAC values varied between 0.2805 and 0.5269 cm-1 for the investigated glasses at 0.81 MeV. BZ30 glass is the more effective shield due to the highest MAC and LAC values.

Tailoring bismuth borate glasses by incorporating PbO/GeO2 for protection against nuclear radiation.

Nuclear radiation shielding capabilities for a glass series 20Bi2O3 - xPbO - (80 - 2x)B2O3 - xGeO2 (where x = 5, 10, 20, and 30 mol%) have been investigated using the Phy-X/PSD software and Monte Carlo N-Particle transport code. The mass attenuation coefficients (µm) of selected samples have been estimated through XCOM dependent Phy-X/PSD program and MCNP-5 code in the photon-energy range 0.015-15 MeV. So obtained µm values are used to calculate other γ-ray shielding parameters such as half-value layer (HVL), mean-free-path (MFP), etc. The calculated µm values were found to be 71.20 cm2/g, 76.03 cm2/g, 84.24 cm2/g, and 90.94 cm2/g for four glasses S1 to S4, respectively. The effective atomic number (Zeff)values vary between 69.87 and 17.11 for S1 or 75.66 and 29.11 for S4 over 0.05-15 MeV of photon-energy. Sample S4, which has a larger PbO/GeO2 of 30 mol% in the bismuth-borate glass, possesses the lowest MFP and HVL, providing higher radiation protection efficiency compared to all other combinations. It shows outperformance while compared the calculated parameters (HVL and MFP) with the commercial shielding glasses, different alloys, polymers, standard shielding concretes, and ceramics. Geometric Progression (G-P) was applied for evaluating the energy absorption and exposure buildup factors at energies 0.015-15 MeV with penetration depths up to 40 mfp. The buildup factors showed dependence on the MFP and photon-energy as well. The studied samples' neutron shielding behavior was also evaluated by calculating the fast neutron removal cross-section (ΣR), i.e. found to be 0.139 cm-1 for S1, 0.133 cm-1 for S2, 0.128 cm-1 for S3, and 0.12 cm-1 for S4. The results reveal a great potential for using a glass composite sample S4 in radiation protection applications.

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 Na2O-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.

Investigation of the gamma ray shielding properties for polyvinyl chloride reinforced with chalcocite and hematite minerals.

Polyvinyl chloride (PVC) is the most widely produced synthetic plastic polymer in the world: it has a variety of applications due to its low cost, elasticity, light weight, good mechanical characteristics and corrosion resistance. In order to protect living beings from harmful radiation such as gamma rays, novel low-cost chalcocite and hematite-based PVCs were fabricated for shielding purposes. The mass attenuation coefficient µm for various fabricated hematite and chalcocite-based PVCs was calculated using MCNP-5 code. The results were compared with the values calculated theoretically using XCOM software between 0.015 and 15 MeV. Moreover, the simulated µm parameter for chalcocite/PVC and hematite/PVC was used to calculate other shielding factors, such as the half value layer (HVL), the mean free path (MFP) effective atomic number Zeff, the geometric-progress (G-P) fitting parameters and the exposure buildup factor (EBF). The simulated data of µm for all composites is comparable to that obtained from a theoretical calculation. The results showed that the addition of hematite and chalcocite enhance the µm of PVC polymers. We also found that the µm of chalcocite/PVC is higher than that of hematite/PVC due to the copper content in the former.

Simulation studies for gamma ray shielding properties of Halloysite nanotubes using MCNP-5 code.

Halloysite clay is a mineral found in natural and it has many applications in chemistry (for catalytic and extraction) and also in the medical field (for drugs delivery), so it is important to study the shielding properties of natural and modified nanotube Halloysite. The mass attenuation coefficient was simulated for natural Halloysite clay mineral and four others modified halloysite nanotubes using MCNP 5 code for incident gamma ray energies between 0.015 and 15 MeV. The mass attenuation coefficient was also calculated using the XCOM database for studied samples in the same energy range. The results obtained by the MCNP simulation were close to those obtained by XCOM calculation. Moreover, other shielding properties that described the interaction of incident gamma rays with Halloysite composites, such as the HVL, MFP, Zeff, and Neff were calculated using the simulated µm for gamma rays between 0.015 and 15 MeV.