This paper reports on the effect of gamma-ray irradiation on single-mode optical fibers, including measurement of the relaxation process. The study was performed using gamma-irradiation facilities with 60Co sources at doses of 67.9 kGy and 170.0 kGy, with irradiation rates of 0.97 kGy/h and 1.05 kGy/h, respectively. We measured changes in optical losses for seven types of optical fibers, including those with germanium-doped silica core and pure silica glass cladding, as well as four optical fibers with pure silica glass and fluorine-doped silica cladding. Measurements of optical losses and radiation-induced attenuation were performed at four wavelengths: 1310 nm, 1490 nm, 1550 nm, and 1625 nm. The gamma irradiation of the fibers and optical loss measurements were conducted at room temperature, and our measurements showed that in harsh environments where gamma rays can irradiate optical fibers, a wavelength of 1310 nm (O-band, 1260-1360 nm) is better suited for data communications than 1550 nm (C-band, 1530-1565 nm).
This study evaluates ten Electro-Geometric Models (EGMs) and one Leader Progression Model (LPM) for predicting lightning strikes to a 220 kV transmission line. Using 15 years of EUCLID lightning-location data (2011–2025) processed through IEC 62858 flash grouping and polarity-specific IC current filtering, we identified 7577 flash events from 18,333 stroke records along an 83.9 km line with eight confirmed fault-causing attachments. Our central finding comes from a one-factor-at-a-time Monte-Carlo analysis (200 realizations per error source): among lightning location, peak current, and stroke-type/amplitude classification, only location error materially changes whether individual confirmed events are detected—for both the geometric (EGM_Young) and physics-based (LPM) models—while peak-current and classification error change it for neither. Because the median location error (89 m) is comparable to or larger than the 43–88 m EGM attractive radii, event-level detection is bounded by geolocation accuracy rather than model choice, and 7 of 10 EGMs detect none of the confirmed attachments. We propose detection ratio and predicted attachment rate as metrics better suited to limited confirmed events with undefined true negatives. The LPM and EGM_Young attain the highest detection ratio (2/8); the LPM predicts 39% fewer total attachments (249 versus 411) at 4.8 × higher computational cost, reported as a model property rather than evidence that either is more accurate. This count ordering is invariant across all three error sources, whereas the detection result, resting on only two detected events, is reported as a sensitivity analysis rather than a full variance decomposition. These models can also screen candidate high-risk segments for maintenance prioritization, subject to the stated limitations.
The application of Haynes 230 (HA230) by Laser Powder Bed Fusion (LPBF) is limited by its high susceptibility to process-induced cracking. TiB2 addition offers a promising route to suppress cracking; however, its effect on the fatigue behaviour of LPBF-processed HA230 remains unclear. In this work, an LPBF-processed HA230 superalloy modified with 1.5 wt.% TiB2 was investigated in terms of its microstructure, tensile properties, and Low-Cycle Fatigue (LCF) behaviour at 23 °C and 850 °C. The addition of 1.5 wt.% TiB2 effectively suppressed LPBF-related cracking and increased the yield strength by approximately 30 % at 23 °C and 20 % at 850 °C while maintaining high ductility. The enhanced strength is attributed to the transformation of TiB2 during LPBF, which resulted in the formation of M6(CB) carboborides and a fine dispersion of Ti-rich and La-rich nanoparticles. These nanoparticles impeded dislocation motion and contributed to strengthening. Under LCF loading, HA230 exhibited pronounced cyclic hardening at 23 °C, whereas cyclic softening predominated at 850 °C. Fatigue crack propagation was predominantly transgranular at both temperatures, although the damage mechanisms depended on the testing condition. At 23 °C, failure was mainly associated with brittle cracking of M6(CB) particles, whereas at 850 °C, oxidation-assisted surface crack initiation and propagation dominated. This study provides the first comprehensive correlation between the microstructure, tensile response, and LCF behaviour of TiB2-modified LPBF-processed HA230, demonstrating that controlled TiB2 addition can simultaneously improve LPBF processability and mechanical performance.
The removal of nitrogen species, particularly nitrates, is critically important for environmental remediation and the production of renewable energy. Converting nitrogen in wastewater into ammonia is an alternative to the Haber-Bosch process, which constitutes an effective and economical method for addressing nitrate contamination in source waters. This process simultaneously facilitates the reclamation of nitrogen as a renewable and promising energy resource. This approach not only decreases dependence on energy-consuming procedures but is also environmentally friendly. Copper-based electrocatalysts for the nitrogen/nitrate reduction reaction (NRR) have been widely studied, yet a comprehensive understanding of the relationships between their preparation, characterization, and catalytic activity remains incomplete. In this review, we aim to provide a structured summary of synthetic approaches for Cu-based electrodes using both physical and chemical methods, highlighting the structure–activity correlations between synthesis strategies and catalyst performance. We also present a thorough overview of advanced characterization techniques, including structural, morphological, compositional, electrochemical, and in situ/operando studies, to identify active sites, reaction intermediates, and degradation pathways. The electrocatalytic performance of Cu-based electrodes in NRR is critically analyzed and compared, with emphasis on the effects of morphology, surface composition, electrolyte selection, and pH on activity and selectivity. Methods for quantifying ammonia, such as colorimetry, NMR, GC, and ion chromatography, are reviewed to ensure benchmarking and reproducibility. Despite these advances, practical application remains limited due to challenges such as the trade-off between selectivity and activity, catalytic deactivation, and competition from the hydrogen evolution reaction (HER). This work aims to provide a consistent and rational framework for screening Cu-based systems toward highly efficient and cost-effective ammonia electrosynthesis.
Ecotourism is increasingly recognized as a sustainable development strategy for environmentally sensitive mountain regions. However, its effectiveness depends on spatially informed planning and community acceptance. This study presents an integrated geo-spatial and socio-economic framework to assess ecotourism suitability and associated impacts in Chitral District, a high-mountain region of Khyber Pakhtunkhwa, Pakistan. A Geographic Information System (GIS) coupled with the Analytical Hierarchy Process (AHP) was employed to delineate ecotourism suitability zones using environmental, topographic, climatic, ecological, cultural, and infrastructural criteria. Multiple thematic layers were created in ArcMap 10.8, weighted through expert judgment, and integrated using a weighted linear combination approach. The resulting ecotourism suitability index classified the study area into five categories: very high, high, moderate, low, and unsuitable. The spatial analysis indicates that approximately 39.4
