Crystal Diffraction Techniques Were Used to Investigate the Structural Properties of Some Aluminum Alloys.

Due to the importance of these alloys in the manufacture of aircraft, coatings, radiation shields, and electronic circuits, the study’s objectives include investigating previously unstudied structural properties of some aluminum alloys, alloy A (Al-Zn-Mg-Ti) and alloy B (Al-Zn-Mg-Mn) were prepared using the casting method, and their structural properties were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques (granular size and theoretical density). The results of analyzing the X-ray diffraction data and determining the phases formed on the two alloys after matching them with the international standard cards (JCPDS) revealed that it is polycrystalline, with structures (cubic and hexagonal) on alloy A and structures (cube, hexagonal, and anorthic) on alloy B. The results revealed that the average grain size estimated by the Debye-Scherer method is less than that estimated by the Williamson-Hall method, and that the grain size of alloy A is less than that of alloy B due to the presence of titanium in alloy A’s composition, which works to reduce particle size. The theoretical density of Alloy A and B that was used in X-ray diffraction was calculated. SEM analysis of the spherical shape of the grains on the surfaces of alloys A and B revealed that the average grain size on the surface of alloy A is smaller than on the surface of alloy B, which is consistent with the results of XRD analyses.

Tuning the 3D Printability and Thermomechanical Properties of Radiation Shields

Additive manufacturing, with its rapid advances in materials science, allows for researchers and companies to have the ability to create novel formulations and final parts that would have been difficult or near impossible to fabricate with traditional manufacturing methods. One such 3D printing technology, direct ink writing, is especially advantageous in fields requiring customizable parts with high amounts of functional fillers. Nuclear technology is a prime example of a field that necessitates new material design with regard to unique parts that also provide radiation shielding. Indeed, much effort has been focused on developing new rigid radiation shielding components, but DIW remains a less explored technology with a lot of potential for nuclear applications. In this study, DIW formulations that can behave as radiation shields were developed and were printed with varying amounts of porosity to tune the thermomechanical performance.

Well-Controlled Emulsion Polymerization of Methyl Methacrylate Using (Hg,Cd)-Diphenylcarbazone Catalysts: An attempt to Create Hg-free, Nontoxic, γ-Radiation and thermal Stable Films

In this work, a procedure for synthesis of Hg and Cd-free PMMA films via emulsion polymerization using different concentrations (0.000025 - 0.00025 g mol/L) of Hg and Cd-diphenylcarbazone complexes (Hg(or Cd)DPC) as a catalytic chain transferring agent was reported. The extraction of either HgDPC or CdDPC from resultants polymers was confirmed using UV-Vis spectrophotometry and the neat polymers presented no cytotoxicity to human Hep G2 Cells. Well dispersity of PMMA (DPI of ca. 1.3) and the optimal performance in MMA polymerization was achieved using 0.00020 g mol/L HgDPC, which exhibited a PMMA yield of ca. 98%. Thermal behavior studies proved that PMMA films became highly thermally stable suggested as due to the elimination of head-to-head growing PMMA chains and disproportionation mechanistic steps. Therefore, the degradation process is mainly due to the random main chain scission, which on turn demonstrated a positive impact on its melting, decomposition and, glass transition (Tg) temperatures where, Tg of PMMA samples understudy increased in the following order: blank(60°C)˂CdDPC(69°C)˂HgDPC(84°C).The radiation shields and mechanical properties of PMMA films were also studied to evaluate the anti-radiation affinity of these complexes where, a tensile strength of 85.0 MPa of resultant PMMA using HgDPC was acquired.

Construction of a Medical Radiation-Shielding Environment by Analyzing the Weaving Characteristics and Shielding Performance of Shielding Fibers Using X-ray-Impermeable Materials

As the scope of radiation use in medical and industrial fields has expanded, interest in radiation shielding is increasing. Most existing radiation shields use Pb-based products, primarily in the form of a laminated sheet, which requires attention as fine cracks may occur depending on the usage and storage conditions. The weight of the sheets limits users’ activities, and they pose a risk of heavy metal contamination. To address these problems, this study proposed a shielding fiber with improved flexibility and workability, and thus, produce a shielding garment. Masterbatches of polyethylene terephthalate (PET) fiber were manufactured using the eco-friendly materials, BaSO4 and Bi2O3. Yarns were fabricated by the melt spinning process, and fabrics were woven. With 5 wt% of shielding material, the yarns’ shield against radiation and was sufficiently strong for fabric weaving. The fibers’ radiation shielding averaged 9–13%, with the Bi2O3 fiber displaying better shielding performance than the BaSO4. It is believed that the findings of this study on improving the yarn manufacturing process could be applied for protection against low-dose and scattered rays in medical applications and for aerospace radiation protection. In addition, the proposed shielding fibers’ flexibility makes them suitable for future use in the production of various radiation shields.

Terahertz Shielding Properties of Carbon Black Based Polymer Nanocomposites

The majority of industry using high-speed communication systems is shifting towards higher frequencies, namely the terahertz range, to meet demands of more effective data transfer. Due to the rising number of devices working in terahertz range, effective shielding of electromagnetic interference (EMI) is required, and thus the need for novel shielding materials to reduce the electromagnetic pollution. Here, we show a study on optical and electrical properties of a series of ethylene co-butyl acrylate/carbon black (EBA/CB) composites with various CB loading. We investigate the transmittance, reflectance, shielding efficiency, absorption coefficient, refractive index and complex dielectric permittivity of the fabricated composites. Finally, we report a material that exhibits superior shielding efficiency (SE)—80 dB at 0.9 THz (14.44 vol% CB loading, 1 mm thick)—which is one of the highest SE values among non-metallic composite materials reported in the literature thus far. Importantly, 99% of the incoming radiation is absorbed by the material, significantly increasing its applicability. The absorption coefficient (α) reaches ~100 cm−1 for the samples with highest CB loading. The EBA/CB composites can be used as lightweight and flexible shielding packaging materials for electronics, as passive terahertz absorbers or as radiation shields for stealth applications.

Attenuation of Earth’s radiation belt electrons with protective shields based on composite W-Cu

For decreasing the radiation effects of the cosmic environment on the electronic components of spacecraft, local protection shields are used. They are manufactured on the basis of materials with high density and large atomic numbers (tungsten, tantalum, the W-Cu composite etc.) and then integrated into the ceramic-and-metal package of electronic components with an insufficient level of radiation resistance. On the basis of the Monte Carlo approach we considered the methods of decreasing the level of the dose absorbed by the crystals of active elements if using the radiation shields based on the W-Cu composite in hybrid metal cases under the action of electrons of a circular orbit with an inclination angle of 30° and an altitude of 8000 km. The electron spectra at the maximum and minimum solar activity were obtained using OMERE 5.3 software. It was established that an increase in the mass thickness of the base and cover of cases with shields up to 1.67 g / cm2 makes it possible to reduce the dose load by 3.5–3.7 times at the minimum and by 3.9–4.1 times at the maximum of solar activity. The optimization of protection by lowering the upper layer of the W-Cu composite to the base to a height of 1.2 mm reduces the absorbed dose by 6.8–9.3 times at the minimum and by 7.6–10.7 times at the maximum solar activity.