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Globally, dams fragment river networks, threatening migratory fishes which require access to distinct habitats to complete their life cycles. Efforts to understand how cumulative effects of multiple dams affect migratory fishes across large regions, such as a country or continent, could help to identify locations for connectivity‐enhancing actions to conserve migratory fishes. To address this, we evaluated cumulative effects of dams on migratory fishes in rivers across nine ecoregions of the conterminous USA. First, using fish data from thousands of sites (N = 45,989), we summarized ecoregional patterns in assemblages, quantifying the number of migratory species comprising assemblages, showing the prominence of potamodromous species across the large region as well as differences in migratory life history traits among ecoregions. Next, we compared the importance of a set of river network fragmentation metrics that captured influences of multiple dams in networks versus other anthropogenic landscape stressors and natural landscape factors that impact migratory fishes by ecoregion. We found that migratory fishes were more sensitive to cumulative dam effects than other stressors including urbanization and agriculture in the eastern USA. To further identify specific effects of environmental variables on potamodromous fishes, we conducted Boosted Regression Trees analysis in the eastern ecoregions. Our results suggested that the key natural influences on river fishes included catchment area as well as river baseflow and air temperature, suggesting that migratory fishes may be affected by changing climate. Additionally, we found that downstream dams were more influential than other human stressors to potamodromous fishes, underscoring the importance of enhancing connectivity within river networks to conserve migratory fishes. Collectively, our results provide new insights in identifying threats to migratory fish species across the USA, providing information that can aid in conserving this vulnerable but ecologically and socioeconomically important group of fishes. [ABSTRACT FROM AUTHOR]

Liquid sloshing is a common phenomenon in ocean engineering, and one which not only affects the stability of ship navigation, but also poses a threat to both the marine environment and human life. Ascertaining how best to reduce the amplitude of liquid sloshing has always been a key problem in ocean engineering. In this study, based on an improved moving-particle semi-implicit method, the BM-MPS method, the damping effect of a vertical slotted screen under rotation excitation was simulated and studied, and the influence of baffle porosity and the rotation amplitude on the resonance period and impact pressure was discussed. The results showed that the porosity had an obvious effect on the resonance period. A significant resonance period transformation happened when the porosity was 0.1, but a porosity of 0.15 was the point at which the maximum impact pressure in the resonance was at its minimum. Meanwhile, the impact duration curve was related to porosity. With the increasing of porosity, the impact duration curve changed from having no peak to a single peak, and then to double peak. In addition, the amplitude of rotation excitation was also one of the factors that affected the resonance period. [ABSTRACT FROM AUTHOR]

The uses of granular hydrogels to assemble macroscopic bulk hydrogels display numerous distinct advantages. However, prior assembly of bulk hydrogels is accomplished by interparticle linking strategy, which compromised mechanical property and thermal stability under hostile conditions. To expand their applications as engineering soft materials, self‐regenerative granular hydrogels via a seamless integrating approach to regenerate bulk hydrogels is highly desirable. Herein, covalent regenerative granular hydrogels (CRHs) are prepared at low‐temperature synthetic conditions and re‐construct bulk seamless hydrogels at high‐temperature aqueous environments. The re‐formed bulk hydrogels display rubber‐like viscoelastic behaviors over a wide range of temperatures from 90 to 150 °C, where the covalent re‐crosslinking reactions homogeneously occurr along the periphery and in the matrix of granular hydrogels, accounting for the increased structural integrity at high temperatures. The bulk hydrogel shows increased elasticity and long‐term thermal integrity at 150 °C for more than six months in the confined fractures. Moreover, regenerative granular CRH‐based bulk hydrogels significantly improve mechanical robustness under destructive pressure. Thus, high temperature water induced regenerative granular hydrogels present the paradigm to treat engineering scenarios such as large fractures for hydraulic fracturing, drilling operation, and disproportionate permeability reduction under extremely hostile conditions during subsurface energy recovery. [ABSTRACT FROM AUTHOR]