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Through resistance welding experiments, the effects of process parameters and heating elements (HE) on the welding strength of carbon fiber reinforced polyamide 6 (CF/PA6) composites were studied. Stainless steel mesh was used as the heating element for welding CF/PA6 composites. The mechanical properties of the weld were tested using a universal testing machine, and the internal structure and fracture of the joint were analyzed by scanning electron microscopy (SEM). The optimal parameters for welding CF/PA6 composites were determined. In addition, the growth of carbon nanotubes (CNTs) on the surface of the metal mesh significantly improved the welding strength, from 14.016 to 16.31 MPa. The experimental results showed that the optimal parameters included 22A current, 0.3 MPa pressure and 35 s welding time, and the optimal specification of the metal mesh heating element was 200 mesh. The burning time of the metal mesh was 10 s, and the optimum pickling time was 30 s. Highlights: The matrix of the composite material is nylon 6.Improved the experimental process for growing carbon nanotubes.Explore the influence of burning time on welding effect through detection. [ABSTRACT FROM AUTHOR]

Highlights This study investigates the impact of coupling agent‐modified resistance welding heating elements on the welding strength of carbon fiber‐reinforced polyamide 6 (PA6) thermoplastic composites. Silane coupling agent KH550 and titanate coupling agent UP‐201 were used to modify heating elements made of 304 stainless steel mesh. Optimal modification parameters for KH550‐modified stainless steel mesh (SSM) were determined using orthogonal experiments, resulting in maximum single lap shear strength (LSS) of 17.05 MPa under specific welding conditions. Comparative tests demonstrated the enhancement effect of UP‐201‐modified SSM on LSS. Additionally, two experimental schemes were used to study the synergistic enhancement effect of KH550 and UP‐201 on the LSS of resistance welded joints. The findings indicate that both coupling agents improve the welding strength, with significant differences in their individual and combined effects. This study explores carbon fiber reinforced Nylon 6, an innovative thermoplastic. Analyzed effects of modified heating elements on joint shear strength. Examined silane and titanate coupling agents' effects on weld joint shear strength. Investigated synergistic effects of silane and titanate agents on weld joint strength. Investigated the synergistic enhancement mechanism of silane and titanate agents. [ABSTRACT FROM AUTHOR]

In addressing the difficulty of forming Fiber Metal Laminates (FMLs), a laminate composed of a 0.1 mm-thick 304 Stainless Steel Foil (SSF) and Carbon Fiber Reinforced Plastics (CFRP) as the base material is prepared using a specific process. Subsequently, forming limit diagrams are obtained through hemispherical bulge forming experiments to investigate the forming performance of FMLs laminates. The damage phenomena of various forming specimens during the thermal stamping process are analyzed. Based on different damage forms, corresponding theoretical models are established to simulate and predict the forming damage modes of FMLs through simulation. The research results indicate that the stamping formability of FMLs is influenced by the damage tolerance of the thin stainless steel foil. During the thermal stamping process, FMLs may experience delamination, fracture/crack of the thin stainless steel foil, and rupture/tearing/wrinkling of the prepreg. To address these issues, cohesive elements, GTN-M-K damage, and Hashin damage models are established, providing a reasonable simulation prediction of the stamping damage phenomena of FMLs. [ABSTRACT FROM AUTHOR]

304 austenitic stainless-steel (SS) strip-based carbon fiber metal laminates (CFMLs) have raised significant concerns, in terms of their mechanical performance. On top of that, the hybrid laminates' interlamination performance is vital in regulating their failure patterns. Along these lines, in this work, SS strips with regulatable micromorphology and composition were obtained by using physical and chemical surface modification strategies, including polishing, acid etching, anodization, and thermal treatment. The shear strength of the treated-SS/epoxy single lap joints (two treated-SS strips bonded by the epoxy resin via hot curing process) was systematically explored, and the origins of the enhancement mechanism were attributed to the resulting surface microstructure, as well as the possible chemical reactions between the treated surface and the curing agent. The etching-anodizing-thermally treated-SS (EAT-SS)/epoxy joint exhibited the maximum shear strength (16.04 MPa) and work of fracture (5.85 kJ·m−2) due to the substantial cohesive failure pattern of the epoxy. The encouraging enhancement was mainly attributed to the synergistic effect of the micro-annular pit and the nanoporous array structure of the EAT-SS surface. These effects induced a significant mechanical interlock and a plausible chemical reaction at the interface, which led to improved bonding strength between the epoxy and treated-SS surface. Overall, in this work, it was demonstrated that the combination of the anodization and thermal treatment can effectively improve the interlamination bonding properties between the SS strip and the epoxy resin due to the combination effect of mechanical interlocking and chemical bonding. [ABSTRACT FROM AUTHOR]

Background/objectives Few studies have examined the effects of the weight status at birth and preschool age on the risk of elevated blood pressure (EBP) in early childhood, and whether the effects can be modified by breastfeeding duration remains unclear. We aimed to evaluate the effects of high birth weight (HBW) with overweight/obese or abdominal obesity on the risk of EBP in preschoolers, and further evaluate the effects classified by breastfeeding duration ( Subjects/methods This cross-sectional study was conducted in 2018 in Zhuhai, China. Out of 2390 3-4-year-old preschoolers originally recruited, a total of 1899 were included in the analysis. Logistic regression analysis was performed to examine the effects of the weight status at the two age points and breastfeeding duration on the risk of EBP. Results Preschoolers with current overweight/obese had a 1.13-fold increased risk of EBP than those with persistent normal weight, irrespective of their birth weight. However, the preschoolers with HBW had no increased risk of EBP, when they became normal weight (OR 1.70, 0.78-3.72). Similar results were found for the current abdominal obesity and the risk of EBP. In addition, the EBP risk of obese status was minimized if preschoolers were breastfed for [greater than or equal to]6 months. Conclusions Obesity status at preschool age can increase the risk of EBP, irrespective of birth weight. However, this EBP risk can be mitigated if HBW changes to current normal weight. Longer breastfeeding duration can partially offset the risk of EBP in preschoolers with obesity status., Author(s): Jiahong Sun [sup.1], Lisha Wu [sup.1], Yuanyuan Zhang [sup.1], Chunan Li [sup.1], Yake Wang [sup.1], Wenhua Mei [sup.2] [sup.3], Jianduan Zhang [sup.1] Author Affiliations: (1) Department of Maternal and [...]

In our previous study, IRX5 has been revealed a significant role in adipogenesis of hBMSCs. Considering the expansion of adipose tissue in bone marrow in aged and ovariectomy‐related osteoporosis, the effect of IRX5 on the osteogenesis of BMSCs still needs to be elucidated. In vivo, models of aging‐induced and ovariectomy‐induced osteoporotic mice, and in vitro studies of IRX5 gene gain‐ and loss‐of‐function in hBMSCs were employed. Histology, immunofluorescence, qRT‐PCR, and Western blot analysis were performed to detect the functions of IRX5 in hBMSCs osteogenic differentiation. RNA‐seq, transmission electron microscopy, Seahorse mito‐stress assay, and Surface Sensing of Translation assay were conducted to explore the effect of mammalian/mechanistic target of rapamycin (mTOR)‐mediated ribosomal translation and mitochondrial functions in the regulation of hBMSCs differentiation by IRX5. As a result, elevated IRX5 protein expression levels were observed in the bone marrow of osteoporotic mice compared to normal mice. IRX5 overexpression attenuated osteogenic processes, whereas IRX5 knockdown resulted in enhanced osteogenesis in hBMSCs. RNA‐seq and enrichment analysis unveiled that IRX5 overexpression exerted inhibitory effects on ribosomal translation and mitochondrial functions. Furthermore, the application of the mTOR activator, MHY1485, effectively reversed the inhibitory impact of IRX5 on osteogenesis and mitochondrial functions in hBMSCs. In summary, our findings suggest that IRX5 restricts mTOR‐mediated ribosomal translation, consequently impairing mitochondrial OxPhos, which in turn results in osteogenic dysfunction of hBMSCs. [ABSTRACT FROM AUTHOR]