In arid and semi-arid regions, soil surface warming is a considerable phenomenon causing a high thermal gradient which makes water flow intensely. The degree of soil temperature is effective on crop production, plant growth and soil microorganisms. In recent years, the ascending trend of temperature has been substantially noticed by researchers in the issues of pointwise climate change and at w...

Leaf size varies by over a 100,000-fold among species worldwide. Although 19th-century plant geographers noted that the wet tropics harbor plants with exceptionally large leaves, the latitudinal gradient of leaf size has not been well quantified nor the key climatic drivers convincingly identified. Here, we characterize worldwide patterns in leaf size. Large-leaved species predominate in wet, h...

A stack with a small critical temperature gradient is desirable for a standing wave thermoacoustic engine to obtain a low onset temperature difference (the minimum temperature difference to start engine’s self-oscillation). The viscous and heat relaxation loss in the stack determines the critical temperature gradient. In this work, a dimensionless critical temperature gradient factor is obtaine...