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There are situations where geotextiles are subjected to uniaxial tensile strain, which may result in noticeable variations in their filtration performance. This study accordingly investigated the behaviors of needle-punched nonwoven geotextiles during tensile testing using in-situ X-ray computed tomography. Furthermore, a numerical analysis of the variation in pore size characteristics was performed by establishing a geotextile model based on the web formation and bonding manufacturing process. The pore size and fiber orientation distributions were subsequently investigated and a model for the changes in the pore characteristics was established and validated. With increasing tension strain in the machine direction, the pore throat size distribution curve exhibited an overall shift towards larger sizes, and the characteristic pore sizes ranging from 10% to 98% either initially decreased, then increased or consistently increased. Furthermore, the fiber distribution was predominantly within the geotextile plane along the machine direction, and as the strain increased, the fibers stretched and aligned along the direction of the tensile load along the machine direction. Finally, the experimental findings of this study and relevant test results from the literature were thoroughly interpreted. The numerical model align well with the actual changes in pore size characteristics observed under tensile strain. • The tensile behaviors of nonwoven geotextiles during testing were revealed in situ with X-ray computed tomography. • The numerical simulation analysis of the pore size characteristics variation was realized by establishing a geotextile mode. • A model for the changes in pore characteristics of the geotextile under tensile strain was established. • The simulation method can well predict the variation in pore size characteristics under uniaxial tensile strain. [ABSTRACT FROM AUTHOR]

A numerical modeling method to reproduce the structures of needle-punched nonwoven geotextile based on the actual manufacturing process (web formation and web bonding) was developed. The geotextile model was built based on the statistical characteristics of the computed tomography (CT) observations, physical and mechanical properties of fibers, and physical parameters of the geotextile. A combination of the finite element model and pore network model method was proposed to obtain the pore size characteristics. The appearance and pore size characteristics before and under uniaxial tensile strains were investigated. It is shown that the method can simulate the geotextile manufacturing process satisfactorily. The pore size distribution (PSD) curves obtained from the model show good agreement with the CT-based results. Moreover, the method can reasonably simulate the tensile behaviors of geotextile under uniaxial tensile strain. The specimen necking phenomenon during the uniaxial tensile test was well reproduced. The PSD curves moved towards the direction of larger pore size with increasing uniaxial strain, and characteristic pore sizes (O 98 , O 95 , O 50 , O 30 , O 10) all show a relatively steady increasing trend. • The structures of nonwoven geotextiles are reproduced by numerical simulation of the actual preparing process (web formation and web bonding). • A FEM-PNM method was proposed to obtain the pore size characteristics of the geotextile model. • The PSD curves obtained from the numerical model show a good agreement with the experimental results based on CT. • The specimen necking phenomenon during the uniaxial tensile test was well reproduced. • The PSD curves moved towards the direction of larger pore size with uniaxial strain, and characteristic pore sizes all show an increasing trend. [ABSTRACT FROM AUTHOR]

Multiple lifestyle-based childhood obesity interventions have been conducted to address childhood obesity, but individual's response to the universal intervention approach varied greatly. Whether gene variants related to children and adolescents' varied responses to obesity interventions remained unclear. To determine the associations of gene variants with the changes in obesity- and metabolism-related indicators after obesity interventions in children and adolescents. Ten databases and registers (including grey literature) were searched. The lifestyle-based obesity interventions in children and adolescents (≤18 years) that reported the changes in obesity- (body mass index (BMI), BMI Z-score, waist circumference (WC), waist-to-hip ratio (WHR), etc) and metabolism-related (glucose, cholesterol, etc) indicators by genotype after interventions were included. Our primary outcome was the mean difference of the changes in BMI Z-score by genotype after interventions, and secondary outcomes were changes in the remaining obesity- and metabolism-related indicators after interventions. We used the random-effects model to synthesize the results. This review included 50 studies (15,354 children and adolescents with overweight/obesity) covering 102 genes and 174 single nucleotide polymorphisms (SNPs). Approximately three-quarters of SNPs showed no evidence of association with the changes in obesity- or metabolic-related indicators after interventions. One quarter of SNPs were minorly associated with the changes in the BMI Z-score (median effect size: 0.001) with little clinical significance. Only 6 (12 %) studies focused on the accumulated effect of multiple gene variants. Gene variants that have been explored appear to play a minor role in lifestyle-based obesity interventions in children and adolescents. More high-quality studies based on the design of randomized controlled trials are needed to examine the accumulated effect of multiple gene variants in childhood obesity interventions. This systematic review and meta-analysis was registered at PROSPERO as CRD42022312177. [ABSTRACT FROM AUTHOR]

The poor wet-oxidation resistance limits the long-life service of SiC f /SiC composites as the hot end components of aero-engines. The stability of SiC f /SiC composites under high-temperature wet oxygen environment can be promoted by more robust SiC matrix. In this work, the effect of Y 2 O 3 on the corrosion behaviors of SiC ceramics in flowing O 2 /H 2 O atmosphere at 1400 ℃ was studied. Duo to the continuous Y 2 Si 2 O 7 layer formed on the surface, SiC-Y 2 O 3 ceramics exhibit much better wet-oxidation resistance than original SiC ceramics. During the oxidation process, Y 2 O 3 dispersed in the ceramics migrates to the surface and reacts with SiO 2 to form β-Y 2 Si 2 O 7. Subsequently, the β-Y 2 Si 2 O 7 aggregates and grows to form a continuous Y 2 Si 2 O 7 layer, inhibiting the corrosion from oxidizing medium to the inner SiC matrix. This study is expected to provide important ideas for the design and structure regulation of wet-oxidation resistant SiC f /SiC composites. [ABSTRACT FROM AUTHOR]