With larger surface areas and nanochannels for mass delivery and gas diffusion, three-dimensional tubular anodic aluminum oxide (AAO) films have practical advantages over two-dimensional AAO films for medical and energy applications. In this research, we have developed a process for batch production of tubular AAO films using a 6061 Al tube. The tubular AAO films have open nano-channels on both sides, with average pore dimensions of about 60 nm and pore densities of about 10⁸ to 10⁹ pore/cm². It was found that the porous AAO material with nano-channel structure exhibited dialysis behavior, allowing for liquid/gas exudation through diffusion between the inner and outer surfaces of the tubular AAO films. Ar gas bearing test and aeration test were conducted to find the pressure bearing capacity of tubular AAO films. It was demonstrated that the AAO film with a thickness of 100 μm can resist an argon pressure up to 8 atm; however, 30 μm AAO film can only withstand 3 atm of Ar gas. The tubular AAO films with exudation characteristics have the potential for applications in advanced technologies, such as liquid or gas filters, drug delivery, and energy applications.

Accurate and reliable estimates of sediment yields from a watershed and identification of unstable stream reaches due to sediment-related disaster are crucial for watershed management, disaster prevention, and hazard mitigation purposes. In this study, we added hydrodynamic and sediment transport modules in a recently developed model to estimate sediment yields and identify the unstable stream reaches in a large-scale watershed (> 100km²). The calibrated and verified models can well reproduce the flow discharge and sediment discharge at the study site, the Shihmen Reservoir Watershed in Taiwan, during several typhoon events. For the scenario applications, the results revealed that the contribution (> 96%) of landslides on sediment supply is much more significant than compared to soil erosion (< 4%). The sediment contribution from the upstream of the hydrological station-Yufeng is approximately 36–55% of the total sediment supply for the rainfall events of 25, 50, 100, and 200 years return period. It also indicates that 22–52% of sediment still remain at foot of the slope and the streams, which become a potential source for sediment hazards in the future. Combining with the bed erosion and deposition depths, flow-induced shear stress from the SRH-2D model, and probability of slope failure within 250 m of stream reaches, the relatively stability of stream reaches can be identified. The results could provide the water resource authorities for reference to take precautionary measures in advance on the stream reaches with high-degree instability.

Qualifying sediment dynamic in a reservoir watershed is essential for water resource management. This study proposed an integrated model of Grid-based Sediment Production and Transport Model (GSPTM) at watershed scale to evaluate the dynamic of sediment production and transport in the Shihmen Reservoir watershed in Taiwan. The GSPTM integrates several models, revealing landslide susceptibility and processes of rainfall–runoff, sediment production from landslide and soil erosion, debris flow and mass movement, and sediment transport. For modeling rainfall–runoff process, the tanks model gives surface runoff volume and soil water index as a hydrological parameter for a logistic regression-based landslide susceptibility model. Then, applying landslide model with a scaling relation of volume and area predicts landslide occurrence. The Universal Soil Loss Equation is then used for calculating soil erosion volume. Finally, incorporating runoff-routing algorithm and the Hunt’s model achieves the dynamical modeling of sediment transport. The landslide module was calibrated using a well-documented inventory during 10 heavy rainfall or typhoon events since 2004. A simulation of Typhoon Morakot event was performed to evaluate model’s performance. The results show the simulation agrees with the tendency of runoff and sediment discharge evolution with an acceptable overestimation of peak runoff, and predicts more precise sediment discharge than rating methods do. In addition, with clear distribution of sediment mass trapped in the mountainous area, the GSPTM also showed a sediment delivery ratio of 30% to quantify how much mass produced by landslide and soil erosion is still trapped in mountainous area. The GSPTM is verified to be useful and capable of modeling the dynamic of sediment production and transport at watershed level, and can provide useful information for sustainable development of Shihmen Reservoir watershed.

Traditional urban stormwater management systems are increasingly strained by expanding impervious ground cover and intense precipitation associated with climate change. Low-impact Development (LID) has emerged as a vital strategy to mitigate these impacts. This study assessed Taiwan’s first large-scale integrated LID installation—the Taoyuan Water Recycling Center, which incorporates bioretention cells, permeable pavements, and green roofs. Simulations performed using the Storm Water Management Model (SWMM) calibrated using field data collected in 2021–2024 demonstrated that these LID facilities reduced runoff volume by as much as 88%, with peak flow reductions reaching 90%. Under short-duration rainfall conditions, LID also reduced the risk of urban flooding by delaying the onset of peak flows. Analysis of six sub-catchments subjected to 24 synthetic storm scenarios revealed facility layout, storage capacity, and contributing drainage area as the principal determinants of LID performance. These findings underscore the need to scale up LID infrastructure—by increasing storage depth as well as spatial coverage—when seeking to enhance the resilience of urban centers to extreme rainfall.

Large eddy simulation (combined with the mixture model) and laboratory experiment were used to investigate the impact of emergent and rigid vegetation on the dynamics of downslope gravity currents in stratified environments. The reliability of the numerical model was assessed with the corresponding laboratory measurements. The results show that the vegetation cylinders lead to severe lateral non-uniformity of the current front, causing more evident lobe and cleft structures. In stratified environments, the smaller driving force leads to less propagating velocity until the current separates from the slope. The transition point (from acceleration to deceleration phases) of current velocity appears earlier as the vegetation becomes denser. The peak value of the bulk entrainment coefficient $E_{buik}$ is inversely proportional to the vegetation density, while the final converged value of $E_{buik}$ is proportional to the vegetation density. Vegetation patches make the degree of fluctuation of the instantaneous entrainment coefficient $E_{inst}$ more intense, and even negative values appear locally, indicating that the gravity current is detrained into the ambient fluid. The velocity profiles of gravity current develop multi-peak patterns in stratified environments due to fingering intrusive patterns. Our analysis reveals that as the vegetation density increases, the generated wakes behind vegetation cylinders increase local entrainment and mixing, causing the density of current flow from vegetation to decrease and reach the neutral buoyancy layer of ambient fluids earlier, finally leading to a smaller separation depth.