This article explores the foundational principles of ionizing radiation and provides a comprehensive overview of its impact on thermoplastic polymers. Ionizing radiation, encompassing gamma rays, X-rays, and electron beams, has been extensively studied due to its capacity to alter the molecular structure of polymers. These changes enable advancements in various applications by promoting molecular crosslinking, controlled degradation, molecular grafting, and crystallinity adjustments. The article delves into the fundamental mechanisms of radiation thermoplastic polymer interactions, including ionization, electronic excitation, and free radical formation. It highlights how these processes lead to structural transformations that enhance the physical, thermal, and mechanical properties of thermoplastic polymers. Factors such as radiation type, absorbed doses, temperature, and environmental conditions are discussed in the context of their role in controlling these modifications. Key practical applications are identified across fields such as medicine, food packaging, aerospace, and industry. Examples include the production of sterilizable medical devices, enhanced food packaging for longer shelf life, and radiation-resistant materials for the aerospace and nuclear sectors. Despite its many advantages, the article also emphasizes challenges such as process variability, polymer sensitivity to radiation, and standardization difficulties. The review underscores emerging research directions, including optimizing irradiation parameters and integrating advanced characterization techniques like Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray diffraction (XRD). The development of new polymer blends and composites, designed for irradiation-induced property enhancement, represents a promising area of innovation.

Conductive composites are a flexible class of engineered materials that combine conductive fillers with an insulating matrix—usually made of ceramic, polymeric, or a hybrid material—to customize a system’s electrical performance. By providing tunable electrical properties in addition to benefits like low density, mechanical flexibility, and processability, these materials are intended to fill the gap between conventional insulators and conductors. The increasing need for advanced technologies, such as energy storage devices, sensors, flexible electronics, and biomedical interfaces, has significantly accelerated their development. The electrical characteristics of composite materials, including metallic, ceramic, polymeric, and nanostructured systems, are thoroughly examined in this review. The impact of various reinforcement phases—such as ceramic fillers, carbon-based nanomaterials, and metallic nanoparticles—on the electrical conductivity and dielectric behavior of composites is highlighted. In addition to conduction models like correlated barrier hopping and Debye relaxation, the study investigates mechanisms like percolation thresholds, interfacial polarization, and electron/hole mobility. Because of the creation of conductive pathways and improved charge transport, developments in nanocomposite engineering, especially with regard to graphene derivatives and silver nanoparticles, have shown notable improvements in electrical performance. This work covers the theoretical underpinnings and physical principles of conductivity and permittivity in composites, as well as experimental approaches, characterization methods (such as SEM, AFM, and impedance spectroscopy), and real-world applications in fields like biomedical devices, sensors, energy storage, and electronics. This review provides important insights for researchers who want to create and modify multifunctional composite materials with improved electrical properties by bridging basic theory with technological applications.

In the present work, the transmission factors of γ-rays are determined in bi-layered shields composed of lead and steel, through a methodology composed of three distinct parts. The buildup calculation was performed using the methodology published by Broder in 1962 [1]. A computational simulation was used through a spherical model, a total of three concentric spheres were simulated, with the source in the center of the spheres. The first sphere represents the lead shield and its radius is represented by the thickness of this material. The second sphere represents the steel shield and its radius is the sum of the thicknesses of the shielding. The third sphere is the vacuum that will determine the number of photons that will pass. To verify if the analytical methodology can be used to calculate the transmission factor of the proposed shield, laboratory experiments were performed with the BGO (Bismuth Germanate) detector. Measurements were only made with the thickness of steel, and with 15 different thicknesses of lead, ranging from 0.11 cm to 2.01 cm, while keeping the steel thickness. Three different thicknesses of steel were used: 0.65 cm, 0.85 cm and 1.40 cm. The work is relevant in the field of radiological and nuclear defense, considering the application of this shield in military vehicles, and the efficiency of the proposed analytical methodology was demonstrated.

Hydroxyapatite (HAp) is a key bioceramic for biomedical applications, but conventional pressureless sintering (PS) requires high temperatures that can promote phase degradation. Here, we compare PS (1100 °C/180 min) and cold sintering process (CSP) (150 °C/450 MPa/30 min) for pure HAp and an HAp composite containing 4 wt.% niobium–phosphate bioglass (BG), using a 2 M H₃PO₄ transient liquid (10 wt.%). CSP increased relative density from 73.10% to 79.92% for HAp and from 68.43% to 83.54% for HAp/BG, representing up to a 22.1% gain compared with PS. One-way ANOVA confirmed a significant effect of processing route/composition on relative density (F(3,24) = 919.69, p < 0.05), and Tukey HSD indicated that all groups differed statistically. SEM revealed a markedly more consolidated and homogeneous microstructure for CSP, particularly for HAp/BG, consistent with enhanced dissolution–reprecipitation and pore filling. XRD showed that PS at 1100 °C led to partial HAp degradation with β-TCP formation, whereas CSP preserved the HAp phase with broader peaks, smaller crystallite size, and higher specific surface area. These results demonstrate CSP as an efficient low-temperature alternative for densifying HAp-based bioceramics, with BG addition further improving consolidation.

This review addresses the application of silicon-germanium (SiGe) semiconductors as electronic components, highlighting their enhanced electronic and physical properties compared to pure silicon semiconductors. SiGe Semiconductors are widely used in high-performance devices, such as heterojunction bipolar transistors (HBTs) and radio-frequency integrated circuits (RFICs), due to their ability to improve speed, efficiency, and overall device performance. Incoporating Ge into Si increases electron mobility, enabling devices to operate at higher speeds and with lower power consumption, which is crucial for portable and low-power applications. Additionally, SiGe semiconductors are compatible with existing Si semiconductor manufacturing processes, facilitating their integration into complementary metal-oxide semiconductor (CMOS) technologies. Another significant benefit is their improved high-frequency performance, making them suitable for applications such as wireless communications and radar technologies. By varying the Ge composition in SiGe, it is possible to adjust the bandgap and lattice strain, providing flexibility in the design of electronic and optoelectronic devices. These attributes make SiGe semiconductors an ideal choice for a wide range of advanced applications where performance and energy efficiency are essential.