We present a repetitive, non-destructive system for generating high-voltage pulses through fast, controlled thermal depolarization of pre-polarized ferroelectric ceramics. This system represents a significant advance in compact pulsed-power devices, where energy is stored in pre-polarized ferroelectrics. In our device, the ferroelectric pre-polarized ceramic is heated above the Curie temperature in a short, well-defined time interval, releasing the stored electrostatic energy bound by spontaneous polarization as a high-voltage pulse with rise times in the 20–50 ns range, peak amplitudes between 50 and 500 kV, and repetition rates from 0.1 to 10 Hz without material degradation. The system incorporates dedicated subsystems for rapid heating, liquid dielectric insulation, reverse-current blocking, adjustable spark-gap switching, nanosecond-scale diagnostics, and active cooling. Applications include high-power microwave generation, compact X-ray flash radiography, high-power laser pumping, and various medical and industrial sectors requiring compact, reusable pulsed-power sources.
To address the challenges and needs of the CEA (Controlled Environment Agriculture) farms, a complex and multi-purpose sensor robotic platform was developed. The objective was to solve the problem of providing a complete set of visual and numeric information in regards to operational environment and specific points of interest within the environment. In this article, an experimental sensor robotic platform model was constructed and tested by integrating technologies such as LiDAR (Light Detection and Ranging) mapping via ROS (Robot Operating System), point-cloud, RGB and IR imaging and image processing algorithms developed with OpenCV (Open Computer Vision) libraries. Real-time control and environment assessment were achieved by integrating an internet access point within the structure of the experimental model. Experiments show that a multi-sensory integration and operation can be successfully achieved within a compact and energy efficient robotic platform, reaching six hours of autonomy The LiDAR-based experiments show that the proposed system can achieve a ±7 𝑚𝑚 mapping precision, greatly enhancing the operation within the environment. Furthermore, the RGB, IR imaging, point-cloud and image processing algorithms proved to optimize the assessment and monitoring operations by providing valuable and precise visual information. The final results show that the proposed solution has great performance in controlled environments and can improve the safety and overall efficiency of CEA farms and related environments.
As the global shift towards hydrogen utilization progresses, this review examines the technical feasibility and environmental impact of blending hydrogen with natural gas, focusing on its implementation in Romania's residential and commercial gas networks. It provides a comprehensive analysis of various topics, including the safety, sustainability, and operational behavior of existing infrastructure when using a 23 % hydrogen blend (G222). Also, the paper reviews studies on material compatibility with hydrogen, focusing on the long-term effects on pipeline materials such as polyethylene (PE) and steel, as well as the potential for embrittlement in high-pressure systems. It also discusses the performance of household appliances with hydrogen blends, highlighting reductions in CO2 emissions by 6-7%, improvements in nitrogen oxide (NOx) emissions, and sustained combustion efficiency above 98 %. Furthermore, the paper addresses the challenges of leak detection and safety measures in hydrogen-enriched networks and examines regulatory frameworks required for a large-scale transition to hydrogen. By synthesizing current research and field studies, this review provides insights into the readiness of natural gas networks for hydrogen integration, offering recommendations for future research and development in optimizing hydrogen blend ratios and ensuring safe implementation.
Extracurricular activities serve as a valuable complement to the formal educational system in terms of their goals, content, and practical execution. These activities adopt a student-centric approach, tailoring their content, methodologies, and tools to individual students' abilities and interests. They offer flexibility, remain optional, and rely on voluntary participation, augmenting the formal educational process while nurturing the development of individual personalities, creativity, and essential competencies (Bocoș, 2017). Technical-scientific activities place a strong emphasis on the formative aspect of learning by identifying effective methods to structure and guide students' engagements (Albulescu, 2008). Through these activities, students amass knowledge, cultivate skills and abilities, and foster attitudes that bridge the gap between theoretical knowledge and its practical application. This questionnaire seeks to investigate the role and significance of technical-scientific activities in skill development. By analyzing the responses, we aim to establish a correlation between students' performance in national assessments and the practical knowledge acquired through extracurricular pursuits. These activities also aid in nurturing students' creativity, problem-solving capabilities, and offer insights into their perspectives on the interactive methodologies employed in organizing extracurricular events. This study was conducted among a cohort of high school students who completed an online questionnaire (N=445). The findings underscore the complementary nature of technical-scientific activities, which, in conjunction with formal education, contribute significantly to the enhancement of competencies in science and technology. The study affords an opportunity to scrutinize the strengths and weaknesses of specialized extracurricular programs, shedding light on students' demands within the realm of science and technology activities and the extent to which these supplementary initiatives can mitigate school dropout rates.
