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Saline soils is porous medium whose thermal conductivity is affected by components and particle shape. However, the particle shapes in geomaterials are various, and the component and its content are in dynamic change as the soil varies between unfrozen and frozen state. In this study, based on the theory of multi-phase medium mixed geothermal conductivity, a new model is developed to explore the dynamic variation characteristics of the thermal conductivity of sulfate soils. The developed model is validated by comparing the experimental results against the calculated ones. Compared with the other two models, the new model is more reasonable and effective, especially in low temperature. [ABSTRACT FROM AUTHOR]

In this study, the necking three-dimensional strain on minimum cross-section at room temperature was performed experimentally and analytically. A modified strain assumption was applied to overcome significant errors in calculating necking strain by Bridgman assumption. Then, one relatively simple strain distribution function was deduced based on equilibrium equation of necking element. To obtain the parameters in this function, the monotonic tensile tests in two kinds of carbon structure steels Q235 and Q345 were carried out. Meanwhile, the Aramis system based on digital image correlation method was adopted to measure the surface axial strain and deformation parameters during the loading process. The experimental and numerical results were compared with the traditional Bridgman strain assumption. The maximum axial strain calculation error the strain distribution function and experiment value was less than 8%, which was obviously less than that calculated by Bridgman assumption. Additionally, the variation law of the three-dimensional strain calculated by this function was consistent with that obtained by the macroscopic analysis of fracture surface. The application of traditional Bridgman formula can be expanded by this study. Meanwhile, it can provide a new idea to study the stress distribution characteristics and better understanding of ductile materials' deformation properties. [ABSTRACT FROM AUTHOR]