Attenuation efficiency of X-ray and comparison to gamma ray and neutrons in composite metal foams

Microstructural and Radioactive Shielding Analyses of Alumix-231 and Alumix-231 Reinforced with B4C/SiC/Al2O3 Particles Produced through Hot Pressing

Al2O3, SiC, and B4C (10%) particle-reinforced Alumix-231 matrix composites and nonreinforced Alumix-231 blocks were produced by pressing under uniaxial pressure using the powder metallurgy method. The Archimedes density of the produced samples was analyzed using microstructures (SEM and EDS), powder size analysis, and theoretical (PSD software) and experimental methods (Co-60 and Cs-137 radiation sources). As a result of the theoretical and experimental calculations, the Alumix-231 + 10% B4C composite material showed the lowest shielding feature against γ radiation, while the Alumix-231 + 10% Al2O3 composite material showed the highest shielding feature.

Heavy alloy based on tungsten and bismuth: fabrication, crystal structure, morphology, and shielding efficiency against gamma-radiation

W-Bi2O3 composites were fabricated using the hot isostatic pressing technique for the first time. The duration of the samples sintering was 3 minutes under conditions of high pressure and temperature. The study of microstructural features and chemical composition of sintered samples was carried out using scanning electron microscopy and energy-dispersive X-ray spectroscopy, respectively. The effect of temperature on the quality of the obtained W-Bi2O3 composites is determined. The densest samples were obtained at a pressure of 5 GPa and temperatures of 25 °C and 500 °C, the densities of which were 18.10 and 17.85 g cm-3, respectively. It is presented that high temperature exposure during sintering adversely affects both the composite density and microstructure due to the redox reaction accompanied by the reduction of Bi and the oxidation of W. The results of the W-Bi2O3 structure study using X-ray diffraction analysis showed that all samples included the main bulk-centered cubic W phase. The presence of the WO2 phase is noted only when the sintering temperature is increased up to 850 °C, which is confirmed by the appearance of diffraction peaks that correspond to 111 and 22-2 crystallographic planes. The shielding efficiency of the W-Bi2O3 composite against gamma radiation using the Phy-X/PSD software was evaluated. A Co60 isotope with an energy of 0.826-2.506 MeV was used as a source of gamma radiation. The calculation results were compared with those for Pb and Bi. Key shielding parameters such as the linear attenuation coefficient, half-value layer, tenth-value layer, mean free path, and effective atomic number are determined. The calculation results revealed that the W-Bi2O3 composite surpasses Pb and Bi in its shielding properties, which makes it promising for use as a prospective material for radiation shielding applications.

Study on the Influence of Reinforced Particles Spatial Arrangement on the Neutron Shielding Performance of the Composites

Particle-reinforced composites are widely applied as nuclear radiation shielding materials for their excellent comprehensive properties. The work aimed to calculate the influence of the functional reinforced particles spatial arrangement on the neutron shielding performance of composites and attempted to explain the influence mechanism by investigating the neutron flux distribution in the materials. Firstly, four suitable physical models were established based on the Monte Carlo Particle Transport Program (MCNP) and mathematical software MATLAB, namely the RSA (Random Sequential Adsorption) Model with particles random arrangement and FCC Model, BCC Model and Staggered Arrangement Model (SA Model) with particle periodic arrangements. Later, based on these four physical models, the neutron transmittance of two kinds of typical B₄C reinforced composites, 316 stainless steel matrix composite and polyethylene matrix composite, were calculated under different energy neutrons sources (0.0253 eV, 50 eV, 50 keV, fission spectrum, ²⁴¹Am-Be spectrum and 14.1 MeV) and the neutron flux distribution in the 316 stainless steel composite was also analyzed under 0.0253 eV neutron and fission neutron sources. The results indicated that the spatial arrangement of B₄C has an impact on the neutrons shielding performance of the composite and the influence changes with neutron energy and B₄C content. It can be concluded that the RSA model and the periodic arrangement models can be used in different calculation cases in the future.

Investigation of shielding properties of impregnated activated carbon for gamma-rays

Carbon related structures are extraordinarily attractive materials for researchers and especially for organic chemistry, besides being the most important basic materials of daily life. The richness of various optical and electronic behaviors has made them one of the rapidly rising materials on the horizon of material science and condensed matter physics. Having the sheets of atoms that are stacked in a disorganized manner makes activated carbon being different from other forms of carbon -graphite- structures. The researches about the shielding properties of activated carbon atoms for gamma-rays are very rare and required to be improved. Since the use of radioactive sources in different fields (nuclear industry, shielding material, radiation biophysics and space research application, etc.) has been increasing expeditiously, the photon interactions with matter has gained more importance in the world of material science technology. In this article, we review the basics of the impregnated activated carbons (AC1 and AC2), as well as the link between the structural behaviors and the gamma shielding properties in terms of both quality and efficiency. Both XCom software and EGSnrc simulation code were used to obtain the theoretical calculations that are significantly important to be able to understand the shielding properties of impregnated activated carbons (AC1 and AC2) for gamma-rays. At the end, the mass attenuation coefficients (μ_m), the total atomic and the electronic cross-sections (σ_t,a and σ_t,e), the effective atomic number and the effective electron density (Z_eff and N_eff), the half value layer (HVL), the tenth value layer (TVL), and the mean free path (MFP) values of such materials were calculated and then compared with those of some other known shielding materials like lead, borosilicate, concrete and vermiculite. The calculated data showed that impregnated activated carbons (AC1 and AC2) are very appropriate and consistent to be one of the candidates for shielding materials of gamma-rays.

Performance of Composite Metal Foam Armors against Various Threat Sizes

The ballistic capabilities of composite metal foam (CMF) armors were experimentally tested against a 14.5 × 114 mm B32 armor-piercing incendiary (API) and compared to various sizes of armor-piercing (AP) ballistic threats, ranging from a 7.62 to 12.7 mm. Three different arrangements of layered hard armors were designed and manufactured using ceramic faceplates (in one layer, two layers or multiple tiles), a combination of ceramic and steel face sheets, with a single-layered CMF core, and a thin aluminum backing. The performance of various CMF armor designs against the 14.5 mm rounds are compared to each other and to the performance of the rolled homogeneous armor standard to identify the most efficient design for further investigations. The percentage of kinetic energy absorbed by the CMF layer in various armor arrangements and in tests against various threat sizes was calculated and compared. It appears that the larger the threat size, the more efficient the CMF layer will be due to a greater number of hollow metal spheres that are engaged in absorbing the impact energy. The results from this study will help to model and predict the performance of CMF armors against various threat sizes and impact energies.

Random model for radiation shielding calculation of particle reinforced metal matrix composites and its application

The work aimed to calculate the radiation biological shielding performance of particle reinforced metal matrix composite (PRMMCs) using more reasonable model instead of conventional Uniform Filling Model, also attempted to provide a basis for the radiation shielding optimal design of such materials. Firstly, RSA (Random Sequential Adsorption) Model and GRM (Grid Random Model) were established based on MATLAB and Monte Carlo Particle transport program MCNP, and then advantages and disadvantages of them were compared. Later, the influences of metal matrix type, particle (B₄C) content, particle shape and particle shape parameters on the biological shielding performance of materials were calculated under different energy neutrons and different thickness shield using random models. Finally, the optimal aspect ratio of regular hexahedral B₄C was calculated by Genetic Algorithm combined with MATLAB and MCNP. It indicated that GRM could be applied to radiation shielding calculation of PRMMCs.

Acoustic Properties of 316L Stainless Steel Hollow Sphere Composites Fabricated by Pressure Casting

In this study, we prepared metal hollow sphere composites (MHSCs) using metal hollow spheres (MHSs) by pressure casting under vacuum conditions, and investigated the acoustic properties. The density of the MHSCs was measured using the mass to volume ratio, the microstructure of the MHSCs was observed using a scanning electron microscope, and the acoustic properties of the MHSCs were tested using an impedance tube. The measured MHSCs showed that the densities of the MHSCs with the random distribution of MHSs with diameter ~3.28 mm (1.74 g/cm3 to 1.77 g/cm3) (MHSC-3.28) were nearly equal to that of the MHSCs with the random distribution of MHSs with diameter ~5.76 mm (1.74 g/cm3 to 1.76 g/cm3) (MHSC-5.76), and lower than that of the MHSCs with the layered structure of MHSs with diameter ~3.28 mm (1.93 g/cm3 to 1.97 g/cm3) (MHSC-LS). Microstructural observations confirmed that the interface region between the MHSs and matrix demonstrated a simple physical combination pattern with pores. The acoustic properties of the MHSCs showed that the sound absorption coefficient of MHSC-LS was lower than that of MHSC-3.28 and higher than that of MHSC-5.76 at off-resonance. The sound absorption coefficient peak value of MHSC-3.28 was higher than that of MHSC-LS, and lower than that of MHSC-5.76 at resonance. The sound transmission loss of MHSC-3.28 was lower than that of MHSC-5.76, which shows the rules are independent from the resonance. The sound transmission loss of MHSC-LS was higher than that of MHSC-5.76 at resonance, but lower than that of MHSC-3.28 at off-resonance. In addition, we discuss the propagation mechanism of the sound waves in the MHSC, which is mainly determined by the distribution of the MHSs in the MHSC.

Rescue effects of ginger extract on dose dependent radiation-induced histological and biochemical changes in the kidneys of male Wistar rats

Radiation is an essential modality in the management of cancer therapy, but its acute and chronic side effects on the normal organs limit the helpfulness of radiotherapy. The deleterious effects of radiation begin with oxidative stress and inflammatory reaction to radiolytic hydrolysis and formation of free radicals. The aim of the current study was to investigate the effect of dose dependent whole body radiation exposure on histological and biochemical alterations in rat kidney. It was also planned to find out whether ginger extract mitigated the deleterious effects of different doses of radiation in rat kidney. Male Wistar rats were exposed to three doses (2, 4, and 8Gy) of γ- ray with or without a 10day pretreatment with ginger extract. After 10days of whole body γ- ray exposure, the results revealed proliferation of glomerular and tubular cells, fibrosis in glomerular and peritubular and a significant increase in 8-OHdG, CRP, cystatin C (in 8Gy), plasma urea and creatinine levels, as well as a significant decrease in total antioxidant capacity of radiation groups compared to those of the control group. Ginger extract administration once daily for 10 consecutive days before exposure to 2-4-8Gy radiotherapy, which ameliorated histological and biochemical alterations in kidneys of the rats entirely or partially compared to those in the ethanol group rats. These findings indicate that whole body exposure to radiation induces kidney damage through oxidative DNA damage and inflammatory reactions, and that these effects can be alleviated using ginger pretreatment as an antioxidant and anti-inflammatory agent.

Attenuation properties of radiation shielding materials such as granite and marble against γ-ray energies between 80 and 1350 keV

In this study, the γ-ray energy-dependent mass and linear attenuation coefficients of various granite and Turkish marble species have been experimentally obtained. Radionuclides (133Ba, 137Cs, 60Co and 22Na) with point geometry were used as γ-ray sources. The absorption capacity of each sample at nine γ-ray energies was measured using a high resolution γ-ray spectrometer equipped with a high purity germanium (HPGe) detector. To obtain the precision of the results (1σ standard deviation of the single value), this procedure was repeated six times for each species of granite and marble, respectively. The energy-dependent mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), the half (HVL) and the tenth value layer (TVL) were calculated following that the MAC and LAC results were compared to the literature values.

Composite and Nanocomposite Metal Foams

Open-cell and closed-cell metal foams have been reinforced with different kinds of micro- and nano-sized reinforcements to enhance their mechanical properties of the metallic matrix. The idea behind this is that the reinforcement will strengthen the matrix of the cell edges and cell walls and provide high strength and stiffness. This manuscript provides an updated overview of the different manufacturing processes of composite and nanocomposite metal foams.