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Impacts of magnitude and texture of variable sediment supply on bedload transport

Zhou Qihang, Wang Lu, Li Qiang, Ma Xudong, Nie Ruihua

Acta Geophysica

2025

Vol. 73, no. 1

593--602

Sediment supply governs the bedload transport and bed morphology in rivers. Up to the present, the impacts of magnitude and texture of variable sediment supply (e.g., induced by flash flood from tributaries) on bedload transport are unknown, limiting the capacity of flood control and river management significantly. The present study conducted flume experiments to investigate the responses of bedload transport to variable sediment supply regimes with different peak supply rates and grain size distributions. The experimental results indicate that: the bedload rate and mass increase with increasing the peak rate of the variable sediment supply, and decrease with an increase in the proportion of coarse particles; the particles coarser than the median grain size of the supplied sediment D50 are primarily stored in the bed, while those finer than D50 are mainly transported downstream; during the variable sediment supply process, the critical Shields stress of sediment has a similar development trend to that of the bedload rate but with a slight ahead of time.

Research on preventive maintenance strategy of Coating Machine based on dynamic failure rate

Gu Dongwei, Nie Ruihua, Han Wenbo, Chen Guang, Jia Ligang

Eksploatacja i Niezawodność

2023

Vol. 25, no. 1

atr. no. 20

In this paper, a dynamic preventive maintenance strategy is proposed for the problem of high maintenance cost rate due to excessive maintenance caused by unreasonable maintenance threshold setting when complex electromechanical equipment maintenance strategy is formulated. Increasing failure rate factor and decreasing service age factor are introduced to describe the evolution rules of failure rate during the maintenance of the coating machine, and the BP-LSTM (BP-Long Short Term Memory Network, BP-LSTM) model is combined to predict the failure rate of the coating machine. A Dynamic preventive maintenance Model (DM) that relies on dynamic failure rate thresholds to classify the three preventive maintenance modes of minor, medium and major repairs is constructed. A dynamic preventive maintenance strategy optimization process based on Genetic-Particle Swarm Optimization (GPSO) algorithm with the lowest cost rate per unit time in service phase is built to solve the difficult problem of dynamic failure rate threshold finding. Based on the historical operating data of the coating machine, a case study of the dynamic preventive maintenance strategy of the coating machine was conducted to verify the effectiveness of the model and the developed maintenance strategy proposed in this paper. The results show that the maintenance strategy developed in this paper can ensure better economy and applicability.