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Tidal bore impact can be strong and destructive, placing estuarine infrastructures under great threat. However, there is a lack of research focusing on accurately estimating the impact pressure exerted by tidal bores. Herein new experiments were conducted to investigate the pressure of tidal bore fronts in a glass flume. Through analysis of instantaneous pressure of three forms of tidal bore, it was observed that the pressure fluctuation of weak and strong breaking bore fronts is characterized by impact pressure. The vertical distribution and maximum impact pressure of tidal bore were studied.The maximum impact pressure of breaking bore fronts appeared around 0.46 times height of it. The relationship between relative impact pressure and height of the tidal bore fronts was found to closely follow a normal probability density function. Through nonlinear regression analysis, an empirical equation was derived to calculate impact pressure, which was validated using observation data from the Qiantang River in China. This equation can be utilized to predict the impact pressure of tidal bore fronts and provide valuable support for estuarine engineering design. [ABSTRACT FROM AUTHOR]

Background and Objective. Musculoskeletal ultrasound imaging can play a role as an accurate tool in offering an accurate diagnosis of shoulder pain. However, it is still not commonly used in mainland China. The aim of this study was to explore the epidemiology and ultrasound imaging characteristics of shoulder pain patients in south China and hoping to use these data in the future development of artificial intelligent ultrasound interpretation of shoulder pathology. Methods. Patients with shoulder pain were recruited in an outpatient rehabilitation clinic at the Third Affiliated Hospital of Sun Yat-Sen University from January 1, 2017, to June 30, 2018. These shoulder pain patients with or without limitation in joint movement can be included in the study. All of them received musculoskeletal ultrasound scanning. Demographic and imaging data including age, gender, duration of shoulder pain, pain side, and pathologies found by musculoskeletal ultrasound imaging were collected and analyzed. Patients were divided into three groups: <45 years (young group), between 45 and 60 years (middle-aged group), and >60 years (elderly group). The rates of various shoulder pathologies were evaluated and compared between the groups. Results. This study recruited a total of 346 patients with shoulder pain. There were more female (62.1%) than male patients (37.9%), with the largest number of patients in the 45-60 years of age group (40.5%). Forty-eight percent of patients had shoulder pain within a period of 3 months. A total of 380 shoulders were assessed using musculoskeletal ultrasound imaging. The occurrence rate of subacromial disorder (83.8%) was the highest. The rate of supraspinatus tendinopathy, acromioclavicular joint degeneration, and adhesive shoulder capsulitis varied significantly between age groups (P < 0.05). The rate of acromioclavicular joint degeneration was the highest in the elderly group followed by the middle-aged and young groups (P < 0.0167). The rate of supraspinatus tendinopathy and adhesive capsulitis in the middle-aged and elderly groups was significantly higher than that in the young group (P < 0.0167). Conclusions. Musculoskeletal ultrasound can be a useful imaging tool in making an accurate diagnosis of shoulder pain. The occurrence rates of different shoulder pain pathologies in all age groups were thoroughly calculated in this study. More female and more subcoracoid disorder patients than western countries are attributed to repetitive lifting in daily life and work in this study. Correlations between these pathologies and their associated images can be a solid foundation for the development of artificial intelligence in diagnosing the cause of shoulder pain. [ABSTRACT FROM AUTHOR]

• Spring tide amplifies more than neap tide in Qiantang Estuary. • Tidal dynamics is strongly influenced by morphological evolution. • A conceptual model of river-tide-morphology interaction is proposed. Understanding tidal dynamics in estuaries is essential for tidal predictions and assessments of sediment transport and associated morphological changes. Most studies on river-tide interaction ignored the influences of morphological evolutions under natural conditions such as the seasonal and interannual variations of river discharge. This study analyzes the multiple-timescale tidal dynamics in the Qiantang Estuary, a macro-tidal estuary in China with an extremely active morphological evolution. A large dataset including water levels at representative stations, river discharges and bathymetries since 1980 has been collected. The results of the analysis show that within a spring-neap cycle, the tidal amplification in the upper estuary is stronger during spring tide than during neap tide. This unexpected behavior is due to the high sediment concentration and the unique longitudinal profile of the estuary. On the seasonal and interannual timescales, the low water levels in the upper estuary depend on the local bathymetrical conditions. Tidal ranges in the upper estuary are larger in the high flow season and years, than in the low flow season and years, due to the erosion at high flow, in contrast to estuaries with less active morphological changes. During low flow season and years, the bed is gradually recovered, the low waters are elevated, and the tidal ranges decrease accordingly. A good relationship exists between the tidal ranges and the depth of the upper estuary. In the lower estuary, the flood dominance increases continuously due to embankment. In the upper estuary, the flood dominance is increased during the high flow periods, explaining the fast sediment input and bed recovery in the post high flow periods. A conceptual model of river-tide-morphology interaction of the estuary is proposed, which is also applicable for other shallow systems. [ABSTRACT FROM AUTHOR]

Abstract: The Hangzhou Bay is a macro-tidal bay located to the south of the Changjiang estuary in China. Along its northern shore, a large-scale tidal channel system has developed, which includes a main northern tidal channel, with a length of more than 50km and a width up to 10km, and a secondary southern tidal channel. A process-based morphodynamic model, incorporating the cohesive sediment transport module of Delft3D, is used to analyze the physical processes and mechanisms underlying the formation and evolution of this tidal channel system. The results show that spatial gradients of flood dominance, caused by boundary enhancement via current convergences, is responsible for the formation of the channel system, due to a combination of the various factors such as funnel-shaped geometry hindering associated with the presence of islands, and flow deviation by the southern tidal flat and so on. The model results agree well with the real morphological features. This study also indicates that the reclamation of the southern tidal flat imposes a profound influence on the morphological evolution of the tidal channel system in the Hangzhou Bay. It is feasible to use the model to simulate long-term estuarine morphological changes with cohesive sediment settings. [Copyright &y& Elsevier]

Many alluvial estuaries worldwide include an inside bar system, a large sediment deposit deeply stretched into the estuary. A good example of such a system is the large sediment deposit in the Qiantang Estuary, China. Its length and height reach 130 km and 10 m, respectively. Bathymetrical comparison reveals that the large bar has moved seaward by around 15 km over the last decades, probably related to the large-scale coastal embankment project. This motivated a quantitative investigation of the impact of estuarine planform on the inside bar development. The bar morphology is reproduced by means of an idealized 1-D morphodynamic model. Model results suggest that the bar movement is related to a decreasing tidal prism, increasing flood dominance in the lower reach and enhanced ebb currents in the upper reach, in response to the embankment. The timescale of the morphological response is only several years. The rapid response is related to the strong tidal currents and large sediment fluxes within the estuary. Sensitivity experiments show that the location and dimensions of the bar are related to the convergence length of the estuary. A decrease of the convergence length causes seaward movement and shortening and lowering of the bar. The bar dimensions also depend on the ratio between river and tidal discharges. When the ratio increases, the bar apex moves seaward and the elevation decreases. The bar movement has significantly influenced the tidal bore in the Qiantang Estuary. • A morphodynamic model reproduces observed seaward movement of a large inside bar in the estuary over the last decades. • Model results show sensitivity to river flow and embankment works on bar dimensions and location. • The bar evolution has significant influence on the tidal bore formation. [ABSTRACT FROM AUTHOR]