High concentrations of radioactive elements are an indicator of the risk of radioactivity. The cesium radionuclide is one of the most important radionuclides. This study investigates the concentration and radiological impact of Cesium-137 (Cs-137) in surface soils within the Al-Zawiya region, Libya. A total of 19 soil samples were collected from various locations in September 2024, including areas near the Al-Zawiya oil refinery. Samples were prepared by drying, sieving, and sealing in Marinelli beakers for 30 days. Activity concentrations were determined using gamma-ray spectroscopy with an n-type HPGe coaxial detector system (GR6022). The specific activity of Cs-137 was calculated from the 661.66 keV photopeak, and corresponding absorbed dose rates and annual effective doses were derived using standard conversion factors. Cs-137 was detected in 9 samples (47.37%), with activity concentrations ranging from 0.1338 to 2.4037 Bq/kg and a mean of 0.6727 Bq/kg. The highest values were not associated with refinery infrastructure, indicating a fallout origin from historical nuclear events rather than local contamination. The resultant absorbed dose rates (0.0041 - 0.0721 nGy/h) and annual effective doses (0.0050 - 0.0109 μSv/year) are orders of magnitude below the public dose limit of 1 mSv/year and negligible compared to natural background radiation.

This research explores the fundamental principles of quantum computing and their application in enhancing communication security through Quantum Key Distribution (QKD) in free-space channels. Classical cryptographic methods face inherent limitations, particularly with the advent of quantum computational capabilities. Quantum mechanics, specifically the principles of superposition and entanglement, offers a robust framework for secure communication, ensuring that any attempt at eavesdropping inevitably perturbs the quantum state, thus revealing the intruder's presence. Through comprehensive simulations, this study analyzes the performance of QKD systems in free-space communication. Key parameters such as transmittance efficiency (𝜂𝑇), Quantum Bit Error Rate (QBER), and Secret Key Rate (SKR) are evaluated. Results indicate that transmittance efficiency in free space generally decreases with increasing zenith angle, with downlink scenarios (day and night) exhibiting higher efficiencies compared to uplink during the night. For all protocols, simulations demonstrate an increase in QBER and a corresponding decrease in SKR as the zenith angle increases, with downlink performance consistently surpassing uplink in terms of a higher SKR and a lower QBER.

ZnO thin films were deposited on stainless steel substrates using the immersion method by immersing the substrates in a sol-gel coating solution at temperatures of 70 °C and 80 °C for varying durations of (1, 2, 3, and 4minutes). The results indicated that increasing the immersion time significantly influenced the film thickness. Optical measurements showed that transmittance at a wavelength of 350nm increased with higher deposition temperatures. Additionally, the Urbach tail energy increased with temperature, whereas the band gap (Eg) decreased markedly. Furthermore, the electrical conductivity of the ZnO films improved with increased temperature and immersion time.