This overview firstly introduces the state-of-the-art research progress in length scale-related fatigue performance of conventionally-fabricated metals evaluated by miniature specimens. Some key factors for size effec...This overview firstly introduces the state-of-the-art research progress in length scale-related fatigue performance of conventionally-fabricated metals evaluated by miniature specimens. Some key factors for size effects sensitive to microstructures including the specimen thickness, grain size and a ratio between them are highlighted to summarize some general rules for size effects. Then, ongoing research progress and new challenges in evaluating the fatigue performance of additive manufactured parts controlled by location-specific defects, microstructure heterogeneities as well as mechanical anisotropy using miniature specimen testing technique are discussed and addressed. Finally, a potential roadmap to establish a data-driven evaluation platform based on a large number of miniature specimen-based experiment data,theoretical computations and the ’big data’ analysis with machine learning is proposed. It is expected that this overview would provide a novel strategy for the realistic evaluation and fast qualification of fatigue properties of additive manufactured parts we have been facing to.展开更多
As one of the most important biological factors that maintain the stability of the largest fixed and semi-fixed desert in China,the Gurbantunggut Desert,the biological soil crusts (BSCs) develop well and play critical...As one of the most important biological factors that maintain the stability of the largest fixed and semi-fixed desert in China,the Gurbantunggut Desert,the biological soil crusts (BSCs) develop well and play critical ecological roles in the desert ecosystem. In this paper,we briefly summarize our research findings since 2002 including species composition,distribution pattern and ecological functions of BSCs in the desert. Our results indicate abundant species diversity of BSCs in the Gurbantunggut Desert in comparison to other deserts in China. At the scales of sand dune or whole desert,the distribution patterns of BSCs are location-specific. The existence of BSCs in this desert could:(1) accelerate the formation of desert soil and the weathering of minerals; (2) accumulate organic matter in surface soil through related species in soil crusts; (3) enhance the abilities of sand surface to resist wind erosion; (4) influence seed germination of vascular plants; and (5) enhance the production of dew deposition on sandy soil surface.展开更多
This study is an attempt to point out the different types of natural hazards in Sudur Paschim province of Nepal where environmental degradation processes such as deforestation,desertification,biodiversity loss,soil cr...This study is an attempt to point out the different types of natural hazards in Sudur Paschim province of Nepal where environmental degradation processes such as deforestation,desertification,biodiversity loss,soil crisp and watershed degradation are rising trends.Using participatory method multi hazard prone areas were identified with type and intensity.Multi criteria evaluation method was applied to prioritize replicable actions with location-specific innovative practices and their legitimization for integrating local and indigenous knowledge into mainstream education,science and policy with a view to incorporate local and indigenous knowledge as live science in disaster and climate change education.Findings of the study reveal that varieties of natural hazards in combination with social factors such as poverty,conflict and inequality have resulted frequent disasters and social vulnerabilities in many parts of the province.Traditionally,indigenous and local people have responded threats of multi hazards by using their traditional knowledge and skills which has evolved over generations,and continue to adapt to future changes.These traditional,often faith-based,beliefs and practices were found to use as the key to their resilience in the face of natural hazards.However,many communities have been lost their knowledge as the elderly die without transferring it to younger members.Behind this proper educational policy and strategic development plans have not been implemented to cope local/indigenous knowledge into practices.Findings of the study indicate that indigenous and local knowledge is a precious province resource that can support the process of disaster prevention,preparedness and response in cost-effective disaster risk reduction.Therefore,policy framework has to prime focus to integrate indigenous and local knowledge,wisdom and skills into mainstream educational programs in order to transfer science into policy and education(words)into practice.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.51771207 and 51571199)
文摘This overview firstly introduces the state-of-the-art research progress in length scale-related fatigue performance of conventionally-fabricated metals evaluated by miniature specimens. Some key factors for size effects sensitive to microstructures including the specimen thickness, grain size and a ratio between them are highlighted to summarize some general rules for size effects. Then, ongoing research progress and new challenges in evaluating the fatigue performance of additive manufactured parts controlled by location-specific defects, microstructure heterogeneities as well as mechanical anisotropy using miniature specimen testing technique are discussed and addressed. Finally, a potential roadmap to establish a data-driven evaluation platform based on a large number of miniature specimen-based experiment data,theoretical computations and the ’big data’ analysis with machine learning is proposed. It is expected that this overview would provide a novel strategy for the realistic evaluation and fast qualification of fatigue properties of additive manufactured parts we have been facing to.
基金supported by the Key Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-YW-336)the National Natural Science Foundation of China (40771114)
文摘As one of the most important biological factors that maintain the stability of the largest fixed and semi-fixed desert in China,the Gurbantunggut Desert,the biological soil crusts (BSCs) develop well and play critical ecological roles in the desert ecosystem. In this paper,we briefly summarize our research findings since 2002 including species composition,distribution pattern and ecological functions of BSCs in the desert. Our results indicate abundant species diversity of BSCs in the Gurbantunggut Desert in comparison to other deserts in China. At the scales of sand dune or whole desert,the distribution patterns of BSCs are location-specific. The existence of BSCs in this desert could:(1) accelerate the formation of desert soil and the weathering of minerals; (2) accumulate organic matter in surface soil through related species in soil crusts; (3) enhance the abilities of sand surface to resist wind erosion; (4) influence seed germination of vascular plants; and (5) enhance the production of dew deposition on sandy soil surface.
文摘This study is an attempt to point out the different types of natural hazards in Sudur Paschim province of Nepal where environmental degradation processes such as deforestation,desertification,biodiversity loss,soil crisp and watershed degradation are rising trends.Using participatory method multi hazard prone areas were identified with type and intensity.Multi criteria evaluation method was applied to prioritize replicable actions with location-specific innovative practices and their legitimization for integrating local and indigenous knowledge into mainstream education,science and policy with a view to incorporate local and indigenous knowledge as live science in disaster and climate change education.Findings of the study reveal that varieties of natural hazards in combination with social factors such as poverty,conflict and inequality have resulted frequent disasters and social vulnerabilities in many parts of the province.Traditionally,indigenous and local people have responded threats of multi hazards by using their traditional knowledge and skills which has evolved over generations,and continue to adapt to future changes.These traditional,often faith-based,beliefs and practices were found to use as the key to their resilience in the face of natural hazards.However,many communities have been lost their knowledge as the elderly die without transferring it to younger members.Behind this proper educational policy and strategic development plans have not been implemented to cope local/indigenous knowledge into practices.Findings of the study indicate that indigenous and local knowledge is a precious province resource that can support the process of disaster prevention,preparedness and response in cost-effective disaster risk reduction.Therefore,policy framework has to prime focus to integrate indigenous and local knowledge,wisdom and skills into mainstream educational programs in order to transfer science into policy and education(words)into practice.
