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With the implementation of China's rural revitalization strategy, the sustainable preservation of traditional dwellings has become a research priority. Moreover, with the aging population in the countryside increasing, the limited mobility of the elderly may result in them receiving daily corneal illuminance too low for a healthy circadian stimulus. This work aims to explore the relationship between circadian and daylighting design parameters inside traditional dwellings and to develop easy-to-use methods for guiding indoor circadian design in traditional dwellings in western Hunan. Additionally, it seeks to promote the digitalization and informatization of traditional dwellings in western Hunan for preservation purposes, aiming to integrate these efforts with sustainable tourism and community development, which supports the local economy while preserving cultural heritage. The main contributions are as follows: (i) Systematic evaluation of the indoor lighting and circadian status of traditional Miao dwellings in western Hunan. (ii) Simplification and application of the CS and corneal illuminance fitting model for guiding circadian design, especially suitable for indirect indoor circadian aspects of lighting in daylight scenarios. The simplified model provides quick circadian design feedback and promotes healthy circadian concepts. Its accuracy has been verified by fitting it with simulation data from Climate Studio daylighting software. (iii) Exploration of daylighting conditions using simulation software, focusing on ρ′ (the area-weighted average of room surface reflectance), ρ (the reflectance of the surface where the first reflection occurs), and the WWR (Window-to-wall ratio) in two different types of traditional dwellings. This also includes defining the dwelling parameter intervals necessary for an appropriate circadian stimulus in traditional Miao dwellings in western Hunan. (iv) The analysis suggests that enhancing ρ′ has a greater effect on circadian lighting than WWR, indicating that increasing ρ′ should be the preferred method for achieving high-quality and efficient circadian lighting. [ABSTRACT FROM AUTHOR]

In this work, we used femtosecond‐laser direct writing to fabricate two kinds of modified structures with opposite refractive‐index changes to build fork‐grating configurations in z‐cut LiNbO3 (LN) crystals. Experimental and simulation results indicate that the fork grating combined with the modified area of the refractive index increased and refractive index decreased produces a more effective diffraction effect at 532 nm. The diffraction results of these fork gratings have been investigated. Compared with the fork grating only with the refractive‐index‐decreased filaments, when the incident beam is at transverse magnetic, transverse electric, and circular polarizations, the diffraction efficiency is improved by 5.3%, 4.3%, and 9.6%, respectively. Our work provides a new perspective for improving the diffraction efficiency of fork gratings in LN crystals. [ABSTRACT FROM AUTHOR]

Separating wake vortices is crucial for aircraft landing safety and essential to airport operational efficiency. Vertical wind, as a typical atmospheric condition, plays a significant role, and studying the evolution characteristics of wake vortices under this condition is of paramount importance for developing dynamic wake separation systems. In this study, we employed the SST k-ω turbulence model based on an O-Block structured grid to numerically simulate the simplified wing model. We analyzed the variations in the wake vortex structure and parameters of the Airbus A320 during the near-field phase under different vertical wind directions and speeds. The results indicate that favorable vertical winds cause a "flattening" deformation in the wake vortex. Vertical winds reduce the initial vortex strength, accelerate the rate of vortex decay, and influence the trajectory of the vortex core. Notably, under wind speeds of 1~3 m/s, the decay rate is more significant than under 4 m/s. When vertical wind speeds are substantial, it can lead to irregular motion and interactions within the vortex core, forming secondary vortices. [ABSTRACT FROM AUTHOR]

Mountains composed of granite are generally regarded as stable geological formations. However, in Alpine and high-altitude mountains in the eastern part of the Tibetan Plateau, geological hazards such as collapses and landslides occur frequently due to the deterioration of granite mechanical properties caused by the freeze–thaw cycles. To investigate this phenomenon, a freeze–thaw cyclic mechanical test is conducted on granite from the Basu area, and the rock's damage trend during the freeze–thaw process is analyzed through wave velocity and nuclear magnetic resonance (NMR) tests. The results indicated that the internal damage of granite increases and its wave velocity decreases significantly with increasing the freeze–thaw cycles, implying a decline in the rock's integrity. Furthermore, the development pattern of the NMR T2 relaxation time distribution indicates that the crack size range of naturally weathered rock samples further increased after freeze–thaw cycles, whereas less-weathered rocks showed a more concentrated range of crack sizes. Triaxial compression tests conducted on rock samples after the freeze–thaw cycles showed that parameters such as the uniaxial compressive strength, elastic modulus, internal friction angle, and cohesion of the rock decreased with increasing freeze–thaw cycles, while a significant change of Poisson's ratio was not observed. Based on the test data and theoretical analysis, a freeze–thaw damage constitutive model of the Basu granite can be established to simulate and predict the overall variation in rock stress and strain under various confining pressures and freeze–thaw cycles. Hopefully, the present study will provide useful guidance for research on the hazard mechanism and hazard prevention of granite sand-sliding slopes in the Basu area. [ABSTRACT FROM AUTHOR]