This paper presents an experimental study on the effect of randomly distributed fibres on enhancing the liquefaction resistance of sand. A series of undrained cyclic triaxial compression tests and hollow cylinder torsional shear tests were conducted on saturated sand samples with and without fibres. The influencing factors (including fibre length, fibre content and relative density), which are closely related to the liquefaction resistance of sand, were investigated. The test results indicated that samples reinforced with randomly distributed fibres can sustain many more loading cycles than can samples without fibres before liquefaction occurs; that is, the inclusion of fibres can effectively improve the liquefaction resistance of sand. The liquefaction resistance increased with increasing fibre length and fibre content. The reinforcement effect is found to be significant in both medium dense samples and loose samples. The results from triaxial tests and hollow cylinder shear tests were similar, indicating that the different loading conditions in the two types of tests will not influence the reinforcement effect of randomly distributed fibres.
In the process of excavation and utilization of the coal gangue hill, gangue at different weathering degree was exposed to the environment, which can be harmful to the surroundings. In order to find the law of heavy metal release and to evaluate the potential ecological risk, five kinds of coal gangue at different weathering degrees were collected from a coal mine named Suncun, an over 100-year-old mine of Xinwen coal mining field located in Tai'an city, Shandong Province of China. Samples were processed with microwave digestion for total content determination of heavy metals, and another part of samples was processed by Tessier sequential extraction for chemical forms analysis. Leaching tests at various pH were carried out to investigate the release of heavy metal. The laws of transformation and release of heavy metals were discussed and potential ecological risk was evaluated. The results indicated that the weathering degree had a significant impact on the content of heavy metal. Exchangeable and carbonate fractions of Cr and Pb were a large proportion of the total and should attract great attention. Potential ecological risk was at strong level (light black) and was up to very strong level (deep black) because of Cd. But Cr had contributed the most for gray gangue, which was 71% of the total. The species of heavy metal in gangue changed due to weathering and lead to the difference of the leaching characteristic and risk.
Background: To assess the efficacy and safety of holmium laser enucleation of the prostate (HoLEP) and transurethral resection of the prostate (TURP) for patients with prostate volume less than 100 mL or 100 g.
Methods:We searched PubMed, Embase, Cochrane Library and Web of Science from inception to July 2021 to collect randomized controlled trials. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies by using the Cochrane risk of bias tool. Review Manager 5.3 software was used for meta-analysis. We synthesised effect estimates using risk ratios (RR), mean difference (MD), and standardized mean differences (SMD).Results: A total of eight studies were included, involving 764 patients, 384 patients in the HoLEP group and 380 patients in the TURP group. The meta-analysis showed that the catheterization time (SMD =−1.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.