Acoustics can cause particles/droplets to agglomerate in the air medium, thereby accelerating gravity sedimentation. To assess the microphysical characteristics and environmental isotope effects of micro-droplet groups under the action of acoustic waves, an air chamber experimental platform was established, and 100 groups of controlled experiments were conducted. The characteristic particle size, size spectrum, isotope values, corresponding linear relationships with hydrogen and oxygen, and d values were analyzed. The isotope exchange equation between the micro-droplet groups and environmental water vapor inside the air chamber was investigated. The results showed that the peak size values of the micro-droplet groups increased under the action of acoustic waves. The characteristic particle size (D₉₀) showed a “trigger effect” with the acoustic operation with a positive deviation in the size spectrum and isotope exchange between the micro-droplet groups and environmental water vapor. The relative variations in theoretical values for different sedimentation conditions were consistent with those of the experimental results. Environment isotopes could be used to trace the acoustic agglomeration process of micro-droplets in the future.

Ultrasound-assisted electrocoagulation (US-EC) shows promise in improving flocculation through cavitation and flow field regulation, yet the mechanisms of flow field evolution and particle size control under acoustic-electric coupling remain underexplored. In this study, an acoustic-electric coupling observation platform for suspended sediment flocculation was established. The motion response characteristics of gas-solid and mixed phases under the intervention of acoustic-electric coupling were observed by employing Particle Image Velocimetry (PIV). Then, the effects of different ultrasonic frequencies and current densities on flow field characteristics, particle size distribution, and flocculation behavior were systematically explored, and ultimately, the synergistic mechanism of US-EC in particle fragmentation and aggregation was revealed. According to the experimental results, low-frequency (28 kHz) ultrasound, owing to a strong cavitation effect, can effectively fragment medium-sized particles while enhancing the specific surface area and fluid disturbances. Meanwhile, high current density (40 A/m²) can accelerate electrolytic reactions and promote rapid reduction of Zeta potential, thereby promoting efficient particle aggregation. Under the operating condition of 28 kHz + 40 A/m², the fluid system maintained a moderate flow velocity (11.01 mm/s) with uniform vorticity distribution, leading to a dynamic balance between disturbance intensity and floc structural stability (15 ≤ η/D < 25, 10^-6 ≲ ε ≲ 10^-4 m² s^-3), which significantly enhanced flocculation efficiency. Accordingly, the average particle size increased from 18.89 μm to 60.98 μm, with a sedimentation rate of 87.96 %. Overall, the US-EC process follows a three-phase evolution path: "ultrasound-induced fragmentation, EC-driven aggregation, gravity-induced sedimentation". The flow velocity and vorticity collaboratively regulate the particle migration paths, collision efficiency, and floc stability, while Zeta potential exhibits a control effect on particle aggregation rate. These mechanisms complement each other temporally to enhance the overall treatment performance.

The root distribution and water uptake of irrigated vines (Vitis vinifera L.) in arid oasis areas remain poorly understood, particularly in terms of the variations in water uptake resulting from plant type and growing period. In this study, excavation and soil coring were employed to investigate the root distribution of vines. Meanwhile, the water uptake dynamics of irrigated vines in an arid oasis area were developed using stable isotopes of hydrogen and oxygen in water bodies (δD and δ¹⁸O) and in crops and soil water, coupled with a direct inference approach and a linear mixed model (IsoSource). The soil layers were divided into nine layers via hierarchical cluster analysis. The results indicated that the vertical distributions of the total and fine roots of grapevines were mainly in the range of 40–160 cm, accounting for 93.1% (91.2%) and 92.5% (90.0%) of the total root (200 cm) distribution during May and October, respectively. In the horizontal direction, both the total root and fine root systems were mainly distributed within 0–100 cm from the trunk and contributed 81.2% and 79.8% of the total root distribution, respectively. Meanwhile, both the total root weight (length) density and fine root weight (length) density decreased gradually with increasing radial distance from the trunk in the 0–80 cm range. The main water uptake of vines was at 0–40 cm in June, 20–80 cm in July, and 40–100 cm in August. These findings suggest that the main depth of root water uptake increases during the whole growth stage for grapevines in arid oasis ecosystems. This information will help growers to improve irrigation efficiency and provide a data analysis of water conservation in an arid oasis area during water stress.

Acoustic agglomeration has been widely recognized as a novel technology for fog elimination and artificial precipitation. In this study, computational fluid dynamics coupled with the population-balance model was applied to investigate the agglomeration process of micro-scale droplets under the combined effects of acoustic waves and turbulent flows. The dynamic processes and distribution of turbulence, vortex characteristics, orthokinetic and hydrodynamic interactions of cloud droplets, as well as agglomeration caused by Brownian motion and turbulent flows, were studied. It was found that there was an eigenfrequency and a threshold sound intensity for acoustic agglomeration. The eigenfrequency of cloud droplets was 50–200 Hz. The threshold intensity for acoustic intervention was in the range of 100–110 dB. When the sound pressure level (SPL) was greater than 110 dB, the median size of the droplets and the spectral width of the droplet volume distribution increased with SPL. The frequency band corresponding to the optimal agglomeration effect of large droplets was relatively low. In such studies involving agglomeration processes, the effect of turbulence on droplet agglomeration should not have been neglected, and the combined effects of sound and flow on the droplet number concentration were more significant than those of pure flow. The effect of acoustic waves on agglomeration became weaker when the flow velocity increased. These insights inform future developments in particle-control technologies and atmospheric precipitation enhancement as well as guide further fundamental research on droplet agglomeration under acoustic fields.

The Tibetan Plateau (TP), known as the “Asian Water Tower,” plays a critical role in regional and global climate systems. However, water resource sustainability is increasingly threatened under climate change and growing demand. While moisture transport mechanisms for summer monsoon and extreme precipitation events have been widely studied, the understanding of moisture sources for different precipitation intensities remains limited. This study employs the Lagrangian-based HYSPLIT model to quantify moisture source contributions to three types of precipitation events—extreme precipitation (EP), moderate precipitation (MP), and light precipitation (LP)—over the TP from 1979 to 2020. Using trajectory clustering and moisture source diagnostics, we identify dominant transport pathways and their relative contributions. Results show that EP and MP events are primarily influenced by the Indian monsoon, with the Bay of Bengal and Arabian Sea as key sources, while LP events are dominated by westerlies. The western pathway contributes 15.55%, 36.28%, and 59.59% to EP, MP, and LP events, respectively, whereas the monsoon pathway accounts for 40.56%, 28.23%, and 31.21%. External moisture sources dominate across all event types (average 87.7%), with local recycling contributions decreasing from LP (12.90%) to EP (11.55%). These findings enhance the understanding of moisture–precipitation coupling mechanisms over the TP and provide a scientific basis for water resource management under changing climate conditions.

Water cycle process will deeply affect water vapour isotope composition, in addition to the evaporation and condensation processes, the exchange process is also a crucial process that influences isotopic variations. To explore the mechanism of isotope exchange under isothermal saturation conditions, we developed an isotope exchange calculation equation for water vapour (IECEWV) based on the conservation of exchange quantity and conducted indoor trials with 100 control groups to validate the IECEWV. The experimental findings demonstrated that the isotopic values of water vapour exhibited enrichment, depletion, and stabilisation during the exchange process when the droplet size first increased and then stabilised, because of the interaction between the exchange state, isotopic gradients, and specific surface area of the droplets according to IECEWV. The variation trend of IECEWV calculated isotopes in water vapour was consistent with experimental value, with average maximum relative errors of 1.66 % for δ²H and 3.19 % for δ¹⁸O, and IECEWV analysis further indicates isotopes exchange can lead to the hydrogen and oxygen isotope line of water vapour deviate from the origin. Furthermore, the linear relationship between hydrogen and oxygen isotopes in water vapour after exchanged can be characterised by linear clusters with the same slope, the d-excess of water vapour remains essentially constant. Future studies may combine the IECEWV with the Rayleigh fractionation model to explore the coordinated changes in precipitation and atmospheric water vapour isotopes.