THE MECHANICAL ANALYSIS OF HDPE NET CAGE BY TEST AND CALCULATION

To reduce the structural failure risk of net cages under extreme sea conditions, this study analysed the yield phenomenon under mooring constraints and excessive or long-term wave loads. The floating collar deforms by shear when a twisted 1 m for the 8-point type and 5 m for the four point type. The structural strength in the Z-vertical direction is one-fifth of that in the X-horizontal direction. The maximum deformation is mainly on the two ends of the cap ned pipes. The critical points of the guardrail may reach the yield stress when the wave height is 1.1 m, while the height of the floating pipe is 5 m. The float can be damaged more easily when there is torsion or shear deformation caused by irregular waves. The results provide guidelines for the optimised structural design of net cages, which by increasing the number of mooring points and cap neds as well as reducing the welding points and structural mutation points, can improve the ultimate bearing capacity and fatigue reliability of the cage float

Halide precursor reduction strategy to modulate bismuthene with high selectivity and wide potential window for electrochemical CO2 reduction

Developing high-performance electrocatalysts for CO2 reduction reaction (CO2RR) is vital in achieving a carbon-neutral society by converting CO2 into valuable chemicals. CO2RR electrocatalyst with lower overpotential, higher selectivity and wider working potential range is urgently desired, but it is still challenging to realize these factors simultaneously. Here, high-performance bismuthene-based electrocatalysts were synthesized by reducing bismuth precursors like BiCl3, BiBr3, and BiI3 in liquid phases. Especially, bismuthene-I derived from BiI3 showed a nanosheet morphology (around four-layer) with significantly enhanced (110) surfaces. It enabled an ultrawide potential window (0.7 V) for high formate selectivity (>90%) in a H-type cell and achieved an ultralow potential (−0.46 V vs. reversible hydrogen electrode) to attain a current density of 200 mA cm−2 in a gas-diffusion flow cell. The prominent long-term operational capability of bismuthene-I was demonstrated in both H-type and gas-diffusion cells. Density functional theory calculations revealed that bismuthene-I possessed abundant topological Bi(110) surfaces states that can reduce the CO2RR overpotential, suppress the competitive hydrogen evolution reaction, and facilitate electron donation during CO2 electrocatalysis. The bismuthene-I realized low overpotential, high selectivity and wide working potential range simultaneously for electrochemical CO2RR. This work unfolds the broader plausibility of facilely reducing precursors for the scalable fabrication of high-performing CO2RR electrocatalysts

Using structural equation modeling to test established theory and develop novel hypotheses for the structuring forces in soil food webs

Understanding the structuring elements of soil food webs is a major challenge for ecologists. Given the complex nature of soil food webs, common treatment-based experiments and bivariate data analyses can only capture part of that complexity. Structural equation model (SEM) is a promising multivariate technique that may help understand direct and indirect relationships in complex soil food webs. As bacterial and fungal energy channels, as well as bottom-up-and top-down forces operate simultaneously, we used SEM to explore the complex interactions among multiple trophic levels in soil food webs. Further, SEM allowed us to test established theory and to refine and derive hypotheses regarding the structuring forces of soil food webs. We studied detritus-based soil food webs in a 55-year-old subtropical Illicium verum forest ecosystem by sampling different important soil food web components, including main soil microbial groups, soil nematodes, and soil microarthropods. The SEM results confirmed established theory by showing the central role of the fungal energy channel, and bottom-up effects were more important for the structure of the food web than top-down forces in the studied subtropical forest soil. In addition, we could derive some novel and refined hypotheses regarding important feeding links in soil food webs. For instance, we provide hypotheses on feeding preferences of different groups of soil biota and on the strength of bottom-up versus top-down effects in forest soil food webs. Overall, we highlight that SEM provides a framework to understand complex interactions and energy pathways in soil food webs in a multivariate context, test established theory, and propose novel experimental tests. (C) 2015 Elsevier GmbH. All rights reserved

The occurrence and development mechanisms of esophageal stricture: state of the art review

Abstract Background Esophageal strictures significantly impair patient quality of life and present a therapeutic challenge, particularly due to the high recurrence post-ESD/EMR. Current treatments manage symptoms rather than addressing the disease's etiology. This review concentrates on the mechanisms of esophageal stricture formation and recurrence, seeking to highlight areas for potential therapeutic intervention. Methods A literature search was conducted through PUBMED using search terms: esophageal stricture, mucosal resection, submucosal dissection. Relevant articles were identified through manual review with reference lists reviewed for additional articles. Results Preclinical studies and data from animal studies suggest that the mechanisms that may lead to esophageal stricture include overdifferentiation of fibroblasts, inflammatory response that is not healed in time, impaired epithelial barrier function, and multimethod factors leading to it. Dysfunction of the epithelial barrier may be the initiating mechanism for esophageal stricture. Achieving perfect in-epithelialization by tissue-engineered fabrication of cell patches has been shown to be effective in the treatment and prevention of esophageal strictures. Conclusion The development of esophageal stricture involves three stages: structural damage to the esophageal epithelial barrier (EEB), chronic inflammation, and severe fibrosis, in which dysfunction or damage to the EEB is the initiating mechanism leading to esophageal stricture. Re-epithelialization is essential for the treatment and prevention of esophageal stricture. This information will help clinicians or scientists to develop effective techniques to treat esophageal stricture in the future