Multidisciplinary Digital Publishing Institute (Switzerland)
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Design and Implementation of an L-Band 400 W Continuous-Wave GaN Power Amplifier
No full textBased on a large-signal chip model, this paper designs and implements an L-band broadband continuous-wave 400 W high-efficiency power amplifier fabricated using 0.5 μm GaN High Electron Mobility Transistor (HEMT) technology. The input-matching circuit employs a hybrid structure combining a lumped-element pre-matching network and a multi-section microstrip capacitor network to achieve impedance matching with a 50 Ω port. The output-matching circuit uses a multi-segment microstrip structure to meet the impedance requirements of the continuous mode, thereby achieving broadband impedance matching. In addition, in the circuit implementation, by optimizing the placement of the blocking capacitor, the current flowing through it is minimized to a low level, enhancing the circuit’s high-power handling capability under continuous-wave operation. Additionally, the power amplifier’s reliability lifetime was calculated based on simulation results of the operating temperature of the GaN amplifier chip. Measurement results demonstrate that across a wide operating bandwidth within the L-band, the output power exceeds 400 W with a drain efficiency greater than 70%. The estimated reliability lifetime (MTTF) of the power amplifier is 8.1 × 107 h
The Provision of Physical Protection of Information During the Transmission of Commands to a Group of UAVs Using Fiber Optic Communication Within the Group
No full textThis paper presents a novel method for the precise localization of remote radio-signal sources using a formation of unmanned aerial vehicles (UAVs). The approach is based on time-difference-of-arrival (TDoA) measurements and the geometric analysis of hyperbolas formed by pairs of UAVs. By studying the asymptotic intersections of these hyperbolas, the method ensures unique determination of the source position, even in the presence of multiple intersection points. Theoretical analysis confirms that the correct intersection point is located at a significantly larger distance from the UAV formation center compared to spurious intersections, providing a rigorous criterion for resolving localization ambiguity. The proposed framework also addresses secure inter-UAV communication via optical-fiber links and supports expansion of UAV groups with directional antennas and low-power signal relays. Additionally, the study discusses practical UAV configurations, including hybrid propulsion and jet-assisted kamikaze platforms, demonstrating the applicability of the method in contested environments. The results indicate that this approach provides a robust mathematical basis for unambiguous emitter localization and enables scalable, secure, and resilient multi-UAV systems, with potential applications in electronic-warfare scenarios, surveillance, and tactical operations
Light Electric Vehicles and Sustainable Transport in Urban Areas: A Bibliometric Review
No full textThe use of light electric vehicles (LEVs), such as electric bikes and electric scooters, is being increasingly adopted as a sustainable transportation solution in urban areas. This is driven by the need for cleaner, faster, and space-efficient mobility solutions in urban areas. Although research on LEVs has grown over time, it remains fragmented across disciplines, creating a need for an integrated study on how LEVs contribute to sustainable transport in urban areas. This study conducted a bibliometric review to identify key themes in LEVs and sustainable transport in urban areas, and proposed future research agendas based on conceptual patterns and research gaps. The Scopus database was utilised, with a focus on 552 publications covering the period from 2000 to 2025, retrieved on 30 September 2025. The Biblioshiny application (version 5.0) was used to perform bibliometric performance analysis and science mapping techniques. Results revealed that the publication trend steadily rose from 2015, with a significant upsurge after 2020, with an annual growth rate of 18.69%. Three dominant themes were identified, namely sustainability, integration with public transport, and technological innovations, alongside underexplored areas such as shared electric micromobility, freight delivery, and policy and governance. Research gaps remain in lifecycle impacts, social equity, and governance frameworks, highlighting the need for inclusive and sustainable LEV adoption. Future research should capture full lifecycle impacts, expand access to LEVs beyond current user groups, and align rapid technological advances with inclusive governance frameworks
Performance of Cementitious Materials Subjected to Low CO2 Concentration Accelerated Carbonation Curing and Further Hydration
No full textExcessive carbonation curing can impair later-age properties; therefore, determining an appropriate carbonation duration is critical for practical low-CO2 utilization. In this study, cement paste and mortar specimens were subjected to accelerated carbonation curing under a diluted CO2 atmosphere (3%) using a concentration-controlled scheme (2.5–3.0%), followed by standard hydration curing for up to 28 d. Carbonation durations of 500, 1000, 2000, and 6000 min were examined. The results show that an early carbonation duration of 1000 to 2000 min achieves an optimal balance between performance enhancement and subsequent hydration development. Compared with the reference specimens, compressive and flexural strengths, as well as durability-related indicators (including electrical flux and EIS parameters), are improved. In addition, the surface microstructure is refined, with a higher proportion of highly crystalline CaCO3 (>70%). In contrast, prolonged carbonation (>2000 min) induces unfavorable microstructural evolution during subsequent hydration, leading to reductions in mechanical performance and durability. These findings provide a practical duration-control strategy for accelerated carbonation curing using low-concentration CO2 streams (3–10%), which are typical of light-industry flue gases
Nonthermal Atmospheric Plasma Modulates Palatal Wound Healing in Rats: A Morphometric, Histopathologic and Immunohistochemical Analysis
No full textBackground/Objectives: Non-thermal atmospheric plasma (NTAP) has recently gained attention as a promising tool for tissue regeneration due to its ability to modulate cellular signaling and enhance wound repair. However, its effects on oral mucosal healing and associated molecular pathways remain insufficiently characterized. This study aimed to investigate the histological and immunohistochemical effects of NTAP on palatal wound healing in rats and to evaluate key biomarkers involved in angiogenesis, proliferation, and extracellular matrix remodeling. Methods: Sixty rats were randomly assigned to three groups: Saline Control Group (SCG), Chlorhexidine Gluconate Group (CHG), and NTAP-Treated Group (NTAPG). Standardized full-thickness excisional wounds were created in the central palatal mucosa. Animals were sacrificed on postoperative days 7, 14, and 21. Histological assessments included vascularization, inflammatory cell infiltration, collagen fiber organization, and epithelial gap measurements. Immunohistochemical analyses were performed using antibodies targeting VEGF-A, TGF-β, FGF-2, CD34, α-SMA, and Ki67 to evaluate angiogenesis, fibroblast activity, and cellular proliferation. Results: NTAP treatment significantly elevated TGF-β levels at all time points and increased α-SMA-positive cell counts on days 7 and 14. FGF-2 expression was the highest in NTAPG, while VEGF-A and CD34 levels were significantly elevated, indicating robust angiogenic activity. NTAP also reduced inflammatory cell infiltration relative to the other groups. NTAPG exhibited enhanced fibroblast proliferation, increased collagen deposition, improved vascularization, and accelerated re-epithelialization compared with SCG and CHG. Conclusions: NTAP significantly promoted palatal wound healing by enhancing proliferative activity, stimulating growth factor expression, and accelerating tissue repair. These findings suggest that NTAP may serve as an effective therapeutic approach for improving oral mucosal wound healing
Impact of Artificial Intelligence Technology on the Sustainable Development Performance of Agricultural Enterprises
No full textThe wide application of artificial intelligence (AI) technology is reshaping the production methods and governance models of agricultural enterprises, laying a solid foundation for them to achieve sustainable development goals. This study examines 245 agricultural listed enterprises on China’s A-share market from 2012 to 2023 as the research sample and uses the double fixed effects model to investigate the impact and mechanism of AI technology on the sustainable development performance (SDP) of agricultural enterprises. Research has found that AI technology has significantly enhanced the SDP of agricultural enterprises. After tests for endogeneity and robustness, the conclusion remains valid. Mechanism tests show that AI technology can enhance the SDP of agricultural enterprises by promoting green innovation and improving the quality of internal control. Through the analysis of moderating effects, it is found that both the information technology background of senior executives and their green background can positively moderate the relationship between AI technology and the SDP of agricultural enterprises. Heterogeneity tests revealed that AI technology has a more significant effect on enhancing the SDP of non-state-owned, small and medium-sized, and processing and manufacturing agricultural enterprises, alongside those in regions with high environmental regulations. The research provides empirical evidence for AI empowering agricultural enterprises’ sustainable development and offers targeted actionable insights to advance agricultural modernization and green transformation
MOX Sensors for Authenticity Assessment and Adulteration Detection in Extra Virgin Olive Oil (EVOO)
No full textFood fraud, particularly in the olive oil sector, represents a pressing concern within the agri-food industry, with implications for consumer trust and product authenticity. Certified products like Protected Designation of Origin (PDO) Extra Virgin Olive Oil (EVOO) are premium products that undergo strict quality controls, must comply with specific production regulations, and generally have a higher market price. These characteristics make them particularly vulnerable to economically motivated adulteration. In this study, the adulteration of PDO EVOO with Olive Pomace Oil (POO) and Olive Oil (OO) was investigated through a combined analytical approach. A traditional technique, gas chromatography–mass spectrometry (GC-MS) combined with solid-phase microextraction (SPME), was employed alongside an innovative method based on an electronic nose equipped with metal oxide semiconductor (MOX) sensors. GC-MS analysis enabled the identification of characteristic volatile compounds, providing a detailed chemical fingerprint of the different oil samples. Concurrently, the MOX sensor array successfully detected variations in the volatile profiles released by the adulterated oils, demonstrating its potential as a rapid and cost-effective screening tool. The complementary use of both techniques highlighted the reliability of MOX sensors in differentiating authentic PDO EVOO from adulterated samples and underscored their applicability in routine quality control and fraud prevention strategies
Lightweight Kalman Spoofing Detection in Platoons of Vehicles
No full textSpoofing attacks remain among the most critical security threats in Connected and Autonomous Vehicles (CAVs). This work introduces a lightweight, two-level spoofing detection framework based on Kalman filtering, designed for real-time deployment in vehicular platoons that communicate over Dedicated Short-Range Communications (DSRC). At the first level, a heuristic residual-based detector identifies abnormal measurement deviations using adaptive statistical thresholds. At the second level, a Mahalanobis distance test assesses model consistency using covariance-aware anomaly scoring at a 95% confidence level. The combination of these complementary mechanisms enables both rapid alerting and robust statistical verification without the need for machine-learning training or centralized processing. Simulation results from 20 independent nodes demonstrate that the proposed approach achieves an average F1-score of 0.92 and Area Under the ROC Curve (AUC) of 0.72, outperforming standalone detectors while maintaining low computational cost. Compared with deep learning and adaptive Extended Kalman Filter (EKF) approaches, the proposed framework achieves similar detection performance while substantially reducing computational complexity and enabling full real-time operation, making it suitable for embedded in-vehicle security modules
Current Status and Future Prospects of Photocatalytic Technology for Water Sterilization
No full textPhotocatalytic water sterilization has emerged as a promising sustainable technology for addressing microbial contamination across diverse sectors including healthcare, food production, and environmental management. This review examines the fundamental mechanisms and recent advances in photocatalytic water sterilization, with a particular emphasis on the differential bactericidal pathways against Gram-negative and Gram-positive bacteria. Gram-negative bacteria undergo a two-step inactivation process involving initial outer membrane lipopolysaccharide (LPS) degradation followed by inner membrane disruption, whereas Gram-positive bacteria exhibit simpler kinetics due to direct oxidative attacks on their thick peptidoglycan layer. Escherichia coli has long been used as the gold standard in photocatalytic sterilization studies owing to its aerobic nature and suitability for the colony-counting method. In contrast, Lactobacillus casei, a facultative anaerobe, can be cultured statically and evaluated rapidly using turbidity-based optical density measurements. Therefore, both organisms serve complementary roles depending on the experimental objectives—E. coli for precise quantification and L. casei for rapid, practical assessments of Gram-positive bacterial inactivation under laboratory conditions. We also describe sterilization using light alone while comparing it to photocatalytic sterilization and then discuss two innovative suspension-based photocatalyst systems: polystyrene bead-supported TiO2/SiO2 composites offering balanced reactivity and separability and magnetic TiO2-SiO2/Fe3O4 nanoparticles enabling rapid magnetic recovery. Future research directions should prioritize enhancing visible-light efficiency using metal-doped TiO2 such as Cu-doped systems; improving catalyst durability; developing new applications of photocatalysts, such as protecting RO membranes; and validating scalability across diverse industrial and medical water treatment applications
The Impact of Strategic Global Integration on Sustainable Human Development in Ethiopia: Disentangling the Roles of Trade and FDI
No full textEthiopia presents a compelling paradox in sustainable development: despite decades of rapid economic growth, improvements in human well-being have not been commensurate. This study examines the role of global economic integration in resolving this paradox by analyzing the impact of trade openness (TOP) and foreign direct investment (FDI) on human development in Ethiopia from 1991 to 2021. We hypothesize that this paradox arises because the benefits of trade and FDI operate primarily through an income-growth channel, with a weaker direct effect on health and education capabilities. Moving beyond the standard Human Development Index (HDI), we construct a modified index (HDI*) that excludes the income component, allowing us to disentangle direct effects on health and education from indirect effects mediated through economic growth. Using the ARDL bounds testing approach, we find that TOP and FDI have significantly stronger long-run effects on standard HDI (0.343 and 0.214, respectively) than on the non-income HDI* (0.235 and 0.136). This indicates that approximately one-third (31.5%) of TOP’s and over one-third (36.4%) of FDI’s total benefit is income-mediated, while the remainder reflects direct capability enhancement. The analysis further reveals that institutional quality significantly amplifies these benefits, whereas inflation specifically undermines non-income dimensions, highlighting the acute vulnerability of social sectors to macroeconomic instability. We conclude that the Ethiopian paradox stems not from a failure of growth but from its weak translation into direct, sustainable gains in health and education. We recommend policies to strengthen institutional governance, attract FDI into health and education sectors, lower trade barriers for agricultural exports, and use trade agreements to address structural trade deficits and promote sustainable human development