Hunan Hydro&Power Design Institute

To improve the accuracy of deformation prediction in concrete buildings and large-scale infrastructures such as dams, this study proposes an Attention-BiLSTM model integrated with a parameter-optimized Variational Mode Decomposition (VMD). Specifically, the Pelican Optimization Algorithm (POA) is employed to optimize VMD parameters, enhancing signal decomposition efficiency for structural deformation time series. The optimized VMD is then coupled with a BiLSTM network embedded with an attention mechanism, forming a hybrid prediction framework that captures both temporal dependencies and key feature weights in monitoring data. Using three sets of engineering-measured deformation datasets, the proposed model is validated through comparative analyses with conventional single models (e.g., standalone BiLSTM and VMD-BiLSTM without attention). Results demonstrate that the developed model achieves superior accuracy and stability, significantly outperforming all comparative methods, with the highest R2 reaching 0.996, while reducing MAE and RMSE by over 60% and 30%, respectively. Quantitative evaluation indicators (e.g., RMSE, MAE, and R2) confirm that the approach effectively captures both short-term fluctuations and long-term trends of structural deformation. These findings verify its reliability and applicability for intelligent safety monitoring of concrete buildings and infrastructures.

Abstract Red mud (RM), an iron‐rich industrial residue generated from alumina refining, poses significant environmental challenges while offering untapped potential for value‐added utilization. This study presents a closed‐loop hydrometallurgical strategy for converting RM into battery‐grade FePO 4 through a process‐optimized leaching–precipitation route. Iron was selectively extracted using a synergistic HCl–H 3 PO 4 acid system under optimized conditions (pH ∼ 1.8, 70 °C, L/S = 7:1), achieving over 80% recovery. Controlled precipitation yielded FePO 4 ·2H 2 O with a purity exceeding 99.5% and a near‐stoichiometric Fe/P molar ratio of ∼0.995. Subsequent thermal treatment and secondary purification jointly enhanced the purity of the final anhydrous FePO 4 product, yielding a phase‐pure material that meets industrial specifications. Multi‐technique characterizations including XRD, SEM‐EDS, TEM, and XPS confirmed the formation of phase‐pure FePO 4 with well‐defined structure and chemical state. This work highlights a scalable and environmentally responsible route for RM valorization, contributing to the sustainable production of energy materials and advancing circular economy practices in metallurgical industries.

The aerodynamic interaction between propeller slipstreams and bifurcated turboprop inlets is not yet fully understood, particularly concerning swirl distortion dynamics and unsteady pressure fluctuations caused by rotating propeller interference. This study combines wind tunnel experiments with sliding-mesh CFD simulations to investigate propeller-induced flow interference. High-frequency unsteady pressure sensors and five-hole probes with a 15° stepwise rotation were used to measure time-averaged and transient flow characteristics. Results indicate that increasing the propeller pitch angle from 40° to 50° raises the total pressure recovery coefficient σ by 0.25% but also increases the total pressure distortion DC60 by 40.4%. Similarly, increasing the propeller speed from 1500 r/min to 2000 r/min enhances σ by 0.34% while causing DC60 to rise by 51.4%. The propeller interference increases the swirl distortion., limiting swirl intensity to 3.43° at 4048 r/min under propeller rotation. This represents a 12.1% increase compared to the 3.06° swirl intensity observed when the propeller is absence. A dominant frequency of 240.3 Hz, corresponding to the blade-passing frequency of the 8-bladed propeller at 1800 r/min, was identified in the wall pressure fluctuations, confirming periodic flow interactions. These findings provide experimental and numerical evidence of the mechanisms behind propeller-induced swirl distortion in bifurcated inlets. The methodology and results directly support the design of advanced turboprop engines requiring improved aerodynamic stability and foreign object exclusion capabilities.

Breakwater dams are critical infrastructures that protect the safety of ports. However, these coastal structures are facing the compounding threats of sea level rise, storm surge, and dam subsidence. Heterogeneous deformations in these infrastructures arise from differential construction sequencing, sediment consolidation, and filling materials, yet traditional in situ monitoring remains spatially limited or even unavailable to trace back and continuously monitor deformation evolutions. In contrast, Interferometric Synthetic Aperture Radar (InSAR) offers valuable insights in providing the spatially and temporally covered dam deformation. In this study, we used two Sentinel-1 tracks from 2016 to 2025, and the persistent and distributed scatterers InSAR methods to map the long-term deformation of Xuwei Port, Lianyungang, China. We utilized six sites of leveling measurements to validate the InSAR-derived vertical deformation and indicate Root Mean Square Errors (RMSEs) ranging from −0.9–1.2 cm. We find, for the rock-sand filled section, the deformations show consolidating subsidence ranging from −63.8 cm to −40.6 cm. In contrast, the concrete tubular structure remains stable, with cumulative deformation ranging from −10.6 cm to −5.2 cm. The enclosing reclaimed land undergoes a period of accelerated settlement with subsidence rates of −64.9–−39.3 cm/yr, which are higher than original subsidence rates of −10.1–−9.7 cm/yr. Additionally, we integrated the consolidation model and tide gauge to quantify that the freeboard will decrease to 0.08–0.31 m in the following 100 years with the continuous sea level rise and dam subsidence. This study benefits our understandings of coastal dam and reclaimed land. It highlights InSAR as a valuable tool to evaluate the critical risk between sea level rise and coastal infrastructure subsidence.

Concrete crack opening (CCO) is of great importance to hydraulic engineering maintenance. A forecast method is put forward combining back propagation neural network (BPNN) and differential equation (DE) for daily CCO modeling and was applied to Wangqingtuo Reservoir, in the northern semiarid region of China and the contribution of the DE was assessed by using BPNN model as a contrast. First, it is made up of BPNN and DE calibrations: (1) use historical data to calibrate BPNN models and obtain residuals; (2) use the particle swarm optimization to calibrate coefficients of the DE. The periodicity and time delay of air temperature is expressed by the DE well.Second, important results were found by field application: (1) the sole BPNN models can provide reasonable predictions; (2) better prediction can be achieved based on BPNN-DE-2TD by increasing KGE, 12% for JB-1, 37% for JB-3, and 6% for JB-7; (3) it is indicated that the addition of DE can improve the modeling on the role of air temperature under seasonal and linear trend, while BPNN part can express the nonlinear role of water level and precipitation well, confirmed by Fourier amplitude sensitivity test sensitivity and Shapley Additive exPlanations analysis. This study could provide useful insights into further forecasting of CCO under this forecast method in the world.

Abstract Glacial lakes are an important component of ice sheet response to climate change. To understand the effect of climate change on glacial lakes, we studied the change characteristics of the glacial lake area, the spatial distribution of glacial lakes, the inter-annual variation of temperature and precipitation and their relationship with the glacial lake pattern in the Greenland ice sheet. The results showed that the area of glacial lakes in the southwest of the Greenland ice sheet increased from 2000 to 2019. The proportion of glacial lake area was relatively small in the low altitude area near the coast, while the proportion of glacial lake area was gradually increasing in the high altitude area of the ice sheet. During this period, the temperature in the study area showed an overall upward trend, but the regional precipitation fluctuated greatly. From 2000-2019, glacial lakes in the southwest of the Greenland ice sheet had a strong response to temperature, but a weak response to regional precipitation. In this study, the interannual variation of the glacial lake area and the influencing factors are more accurately studied by the remote sensing method, which can provide the scientific basis for understanding global climate change and its potential impact on glacial lakes.