This study investigates the fatigue behavior of AA6061-T651 aluminum alloy joints produced by gas metal arc welding (GMAW) and friction stir welding (FSW), in as-welded (AW) and postweld aged (PWA) conditions. Postweld aging was performed at 200 degrees C for 8 h, and fatigue tests were conducted at stress ratios of R = 0.1 and 0.5. The PWA-FSW joints exhibited the highest fatigue strength, reaching about 90 MPa at R = 0.1, representing nearly 30% improvement over untreated FSW joints and 40%-45% over GMAW joints. Increasing the stress ratio reduced fatigue life due to diminished crack-closure effects and multiple crack initiation sites. Microstructural analysis using OM, OIM, and TEM revealed finer grains and stable precipitate distributions in PWA-FSW joints, directly enhancing fatigue resistance. Fractographic examination confirmed distinct crack initiation, propagation, and final fracture regions influenced by stress ratio. The experimental S-N results agreed well with Eurocode 9 design curves for structural design validation.
Reconstructing paleoclimatic conditions in the westerlies-dominated Karakoram is essential for understanding the response of high-altitude arid regions to global climate variability. This study presents a reconstruction of the Last Glacial Maximum (LGM) extents of 15 glaciers in the Nubra-Shyok valley, eastern Karakoram, using preserved glacial geomorphology in combination with the GlaRe model. The valley, situated within the influence zone of the mid-latitude Westerlies, provides an exceptional setting to assess westerlies-driven glacial behavior. The reconstructions indicate that the main Siachen trunk glacier (NS1) Acovered an area of approximately 692 km(2), with modeled ice thicknesses ranging between 200 and 400 m, reaching a maximum of about 370 m. Equilibrium Line Altitudes (ELAs) Awere estimated using a weighted average of four established geomorphometric approachesA(AABR, AAR, MELM, and THAR). AThe results indicate a marked ELA depression of similar to 700 m for the Siachen glacier during the LGM. Based on a locally derived lapse rate, this ELA depression corresponds to the lowering of summer temperature by 1.5-2.0 degrees C, suggesting that enhanced westerlies-induced precipitation moderated the regional expression of global LGM cooling. A distinct spatial ELA pattern is also evident: east-facing glaciers show significantly higher values than west-facing glaciers. This asymmetry reflects the combined effects of westerlies-controlled moisture distribution and differential solar insolation influencing ablation processes. These findings provide robust quantitative constraints on the extent of LGM glaciation and the prevailing paleoclimatic conditions in the valley, highlighting the primary influence of mid-latitude westerlies in modulating glacier dynamics and temperature regimes across this high-elevation region of the Himalaya.
Lightning is a natural, unpredictable event with high current, voltage, and heat. An inadequate lightning protection system (LPS) can put surrounding structures, people, and expensive equipment at risk, resulting in human life (R1), critical services (R2), and cultural heritage (R3) loss. It is essential to identify the key parameters for mitigating lightning risk. This manuscript will guide readers in the assessment of lightning risk as specified in the IEC 62305-2:2010-12-part 2 standard for structures containing explosive materials. Lightning risk assessments aim to reduce all risk factors by using appropriate protective measures. Starting with the structure’s unprotected state, minimize remaining risk until lightning risk analysis reaches the acceptable risk threshold. Numerous case studies here aim to determine how changing lightning protective techniques affects lightning risk assessment findings. Based on the findings of case studies, this manuscript recommends appropriate procedures for selecting lightning protection systems. To get a more precise estimate of human life loss risk, the duration of presence and the number of individuals in the explosive zone are also taken into account.
In this work, 1 wt% Ho-doped K0.5Na0.5NbO3 (KNN) lead-free piezoceramics were synthesized via a conventional solid-state route, with calcination at 1050 degrees C and sintering at 1125 degrees C. X-ray diffraction confirmed the formation of a single-phase orthorhombic perovskite structure in both pure and doped samples. Microstructural analysis revealed a reduction in grain size upon incorporation of Ho3+. The doped ceramic exhibited enhanced functional properties, including an increased Curie temperature (Tc similar to 220 degrees C at 1 KHz), improved piezoelectric coefficient (d(33) = 325 pC/N), and well-defined ferroelectric behavior (E-c = 5.72 kV/cm, P-r = 105.61 mu C/cm(2)). The effective piezoelectric coefficient (d(33)& lowast;) reached 515.93 p.m./V. A fabricated energy harvesting device based on Ho-doped KNN generated an open-circuit voltage of 52.41 V, short-circuit current of 1.32 mu A, power density of 3.38 mu W/cm(2), and sufficient to illuminate fourteen LEDs. These findings highlight the potential of Ho-doped KNN as an efficient lead-free material for energy harvesting and ferroelectric device applications.
Contemporary businesses that aim for sustainable global supply chains (GSCs) through circular economy (CE) models has been a crucial topic of research and practice for addressing the climate change risks and resource scarcity. This study identifies and prioritizes the critical success factors (CSFs) for digitalization assisted CE for sustainability in GSCs using a modified multi criteria decision making technique, Grey Decision-Making Trial and Evaluation Laboratory (DEMATEL). Analysing the cause-and-effect relationships among 14 identified CSFs for digitization assisted CE in GSCs offers actionable insights for organizations and policymakers seeking to enhance sustainability efforts by navigating the complexities of integrating digitization and CE practices. The findings from the study reveal that process improvement and optimization through digitization and human centric sustainable operations towards CE as the highest ranked CSFs. The results suggest that managers shall invest in digital integration, prioritize transparency, and foster collaboration to create resilient and sustainable supply chain ecosystems and this will serve as the initial step towards the future digital transformations. This study provides a strategic roadmap for managers and policymakers aiming to integrate CE principles through digital transformation.
