Fatigue Strength Assessment of Semi-Submersible Floating Wind Turbine Foundation under Turbulent Wind

Under the complex marine environment load and the role of the upper wind turbine load, deep sea floating wind turbine support structure would suffer fatigue damage, which often endangers the safety of the wind turbine system. This paper chose the "5 MW baseline" wind turbine model which published by the US National Renewable Energy Laboratory (NREL) as the design basis. The paper uses the OC4-DeepC wind semi-submersible offshore wind turbine model for the verification of offshore floating wind turbines. According to the characteristics of stress and the distribution of stress, the paper selects seven key parts which are prone to fatigue damage are screened, respectively established local finite element models and carried out grid encryption. Based on the SESAM hydrodynamic analysis software and FAST wind motor dynamic load calculation procedure, the fatigue damage of the target node under the action of wind turbine load is studied. The results show that the structural fatigue damage occurs mainly at the horizontal connection of the upper part of the neutral column and the diagonal connection of the lower part of the neutral column. The fatigue damage degree of the crown and the saddle point is relatively large at the connecting rod position

Vision-based tactile intelligence with soft robotic metamaterial

Robotic metamaterials represent an innovative approach to creating synthetic structures that combine desired material characteristics with embodied intelligence, blurring the boundaries between materials and machinery. Inspired by the functional qualities of biological skin, integrating tactile intelligence into these materials has gained significant interest for research and practical applications. This study introduces a Soft Robotic Metamaterial (SRM) design featuring omnidirectional adaptability and superior tactile sensing, combining vision-based motion tracking and machine learning. The study compares two sensory integration methods to a state-of-the-art motion tracking system and force/torque sensor baseline: an internal-vision design with high frame rates and an external-vision design offering cost-effectiveness. The results demonstrate the internal-vision SRM design achieving an impressive tactile accuracy of 98.96%, enabling soft and adaptive tactile interactions, especially beneficial for dexterous robotic grasping. The external-vision design offers similar performance at a reduced cost and can be adapted for portability, enhancing material science education and robotic learning. This research significantly advances tactile sensing using vision-based motion tracking in soft robotic metamaterials, and the open-source availability on GitHub fosters collaboration and further exploration of this innovative technology (https://github.com/bionicdl-sustech/SoftRoboticTongs)

Spatial heterogeneity of natural and socio-economic features shape that of ecosystem services. A large-scale study on the Yangtze River economic Belt, China

International audienceInvestigating large-scale spatial patterns of ecosystem services (ESs) and their underlying drivers can greatly contribute to policies-making and regional sustainability development. With water yield (WY), soil conservation (SC), and carbon sequestration (CS) as representative ESs, we aim to quantify their spatial patterns in the Yangtze River Economic Belt, China, and to identify their driving factors, and to formulate sound environmental management strategies. Spatial geography and socioeconomic data from 2000 to 2020 were mined and a range of research methods, including multiscale geographic weighted regression, self-organizing maps, and linear discriminant analysis, were employed for such a purpose. Annual average WY, SC, and CS were 403 mm, 9897 t·km−1, and 1071 g·CO2·m−2. The three ESs examined exhibit spatial heterogeneity. WY exhibited significant patterns of variation along the north–south gradient, while SC and CS exhibited significant variation along the topographic gradient. In the context of high correlation of driving factors among ESs, WY and SC exhibited a greater sensitivity to natural factors (such as precipitation), while CS demonstrated a height sensitivity to human activities in addition to vegetation cover. Spatial heterogeneity is pronounced among the main driving factors of ESs. Three threshold equations were established to describe the manner in which driving factors of different regional ecosystem services undergo transformations, equations possessed a high level of credibility in this study (coincidence > 80 %). This study reveals spatial variations in ecosystem services and their natural and socio-economic drivers. More specifically, we quantitatively validated the threshold in the expression of ecosystem service drivers, establishing a strong scientific foundation for regional ecosystem conservation and management

Enhanced CD4+ T Cell Proliferation and Th2 Cytokine Production in DR6-Deficient Mice

AbstractWe have found that DR6, a member of the TNF receptor family, is highly expressed in resting T cells and downregulated in activated T cells. DR6-targeted mutant mice were generated and showed normal development. However, DR6−/− CD4+ T cells hyperproliferated in response to TCR-mediated stimulation and protein antigen challenge. Activated DR6−/− CD4+ T cells exhibited upregulated CD25 expression and enhanced proliferation in response to exogenous IL-2 stimulation. In addition, increased CD28 and reduced CTLA-4 expression were observed in these cells. Enhanced Th2 cytokine production by activated DR6−/− CD4+ T cells was associated with the increased transcription factor NF-ATc in nuclei. DR6, therefore, functions as a regulatory receptor for mediating CD4+ T cell activation and maintaining proper immune responses

The plant hormone abscisic acid stimulates megakaryocyte differentiation from human iPSCs in vitro

In the clinic, the supply of platelets is frequently insufficient to meet transfusion needs. To address this issue, many scientists have established the derivation of functional platelets from CD34+ cells or human pluripotent stem cells (PSCs). However, the yield of platelets is still far below what is required. Here we found that the plant hormone abscisic acid (ABA) could increase the generation of megakaryocytes (MKs) and platelets from human induced PSCs (hiPSCs). During platelet derivation, ABA treatment promoted the generation of CD34+/CD45+ HPCs and CD41+ MKs on day 14 and then increased CD41+/CD42b+ MKs and platelets on day 19. Moreover, we found ABA-mediated activation of Akt and ERK1/2 signal pathway through receptors LANCL2 and GRP78 in a PKA-dependent manner on CD34+/CD45+ cells. In conclusion, our data suggest that ABA treatment can promote CD34+/CD45+ HPC proliferation and CD41+ MK differentiation