A general mathematical modelling for heat and mass transfer in unsaturated porous media: an application to free evaporative cooling

The present paper develops a general mathematical model with some improvements in mass, momentum and energy equations, which introduce more transport mechanisms to simulate simultaneous transfer of heat and mass in the porous media unsaturated with liquid. Numerical calculation results in two-dimension are obtained for the vertical packed bed with its right opening surface exposing to atmospherical environment. The calculating data can demonstrate the cooling effect of the water evaporation for the bed if it is used as a cooling wall of building for room air-conditioning in the hot and dry climate.     

A FORM INVARIANCE OF CONSTRAINED BIRKHOFFIAN SYSTEM

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｔｕｄｙｏｆｔｈｅｄｙｎａｍｉｃｓｏｆＢｉｒｋｈｏｆｆｉａｎｓｙｓｔｅｍｉｓａｎａｃｔｉｖｅｂｒａｎｃｈｉｎｔｈｅｍｏｄｅｒｎｃｌａｓｓｉｃａｌｍａｔｈｅｍａｔｉｃｓａｎｄａｍｏｄｅｒｎｄｅｖｅｌｏｐｉｎｇｄｉｒｅｃｔｉｏｎｉｎｍａｔｈｅｍａｔｉｃｐｈｙｓｉｃｓ ,ａｎｄｃａｎｂｅａｐｐｌｉｅｄｔｏｑｕａｎｔｕｍｍｅｃｈａｎｉｃｓ,ｓｔａｔｉｓｔｉｃａｌｍｅｃｈａｎｉｃｓ ,ｂｉｏｌｏｇｉｃｐｈｙｓｉｃｓ,ｍｅｃｈａｎｉｃｓｏｆｓｐａｃｅｆｌｉｇｈｔａｎｄｓｏｍｅｆｉｅ…     

ON THE STABILITY BOUNDARY OF HAMILTONIAN SYSTEMS

ＩｎｔｒｏｄｕｃｔｉｏｎＭａｎｙｍｅｃｈａｎｉｃａｌｓｙｓｔｅｍｓｃａｎｂｅｖｉｅｗｅｄａｓｌｉｎｅａｒＨａｍｉｌｔｏｎｉａｎｓｙｓｔｅｍｓ.Ｗｈｅｎｗｅｓｔｕｄｙｔｈｅｅｆｆｅｃｔｓｏｆｓｙｓｔｅｍｐａｒａｍｅｔｅｒｓｏｎｔｈｅｂｅｈａｖｉｏｒｏｆｔｈｅｓｙｓｔｅｍｓ,ｔｈｅｓｙｓｔｅｍｃａｎｂｅｒｅｇａｒｄｅｄａｓｔｈｅｓｙｓｔｅｍｄｅｐｅｎｄｉｎｇｏｎｐａｒａｍｅｔｅｒｓ.Ｖｅｒｙｉｍｐｏｒｔａｎｔｓｙｓｔｅｍｐａｒａｍｅｔｅｒｓ ,ｓｕｃｈａｓｃｒｉｔｉｃａｌｌｏａｄ ,ｃｒｉｔｉｃａｌａｎｇ…     

A STRESS VECTOR-BASED CONSTITUTIVE MODEL FOR COHESIONLESS SOIL (Ⅰ)-THEORY

On the basis of the sufficient consideration of vectorial characteristics of stress, a new nonlinear constitutive model for cohesionless soil under plane strain and 3-D conditions was presented in a way that the action effects of stress vector are decomposed into the action effect of mean effective stress and that of the stress ratio vector (ratio of deviatoric stress vector to mean effective stress). The constitutive model can take account of the influence of both numerical and directional changes of stress vector on deformation of soil simultaneously, and is applicable of both static and dynamic loading. Biography: Shi Hong-yan (1964-)     

SEMI-ANALYTICAL AND SEMI-NUMERICAL METHOD FOR DYNAMIC ANALYSIS OF FOUNDATION

A semi-analytical and semi-numerical method is proposed for the dynamic analysis of foundations. The Lamb's solution and the approximate formulae were used to establish the relation of the contact force and deflection between the foundation and soil. Therefore, the foundation can be separated from soil and analyzed by FEM as for the static cases. The plate can be treated as that the known forces are acting on the upper surface, and the contact pressure from soil can be represented as the deflection. So that only the plate needs to be divided into elements in the analysis. By this method, a series of vibration problems, including various shapes and rigidities of foundations, different excitation frequencies, were analyzed. Furthermore, it can be used for the embedded foundation. The numerical examples show that this method has simplicity, highly accurate and versatile. It is an effective method for the dynamic analysis of foundations.     

Periodicity and strict oscillation for generalized lyness equations

ＩｎｔｒｏｄｕｃｔｉｏｎＣｏｎｓｉｄｅｒｔｈｅｆｏｌｌｏｗｉｎｇｄｅｌａｙｄｉｆｆｅｒｅｎｃｅｅｑｕａｔｉｏｎｘｎ 1=ｘｎ(ａ ｂｘｎ)ｘｎ- 1,　　ｎ=0 ,1 ,2 ,… ,(1 )ｗｈｅｒｅａ ,ｂ∈ [0 ,∞ )ｗｉｔｈａ ｂ>0 (2 )ａｎｄｗｈｅｒｅｔｈｅｉｎｉｔｉａｌｖａｌｕｅｓｘ- 1ａｎｄｘ0 ａｒｅａｒｂｉｔｒａｒｙｐｏｓｉｔｉｖｅｎｕｍｂｅｒｓ.Ｅｑ .(1 )ｉｓｒｅｇａｒｄｅｄａｓａｇｅｎｅｒａｌｉｚｅｄＬｙｎｅｓｓｅｑｕａｔｉｏｎｂｙＧ .Ｌａｄａｓｉｎ [1 ] .Ｏｂｖｉｏｕｓｌｙ ,ｕｎｄｅｒｃｏｎｄｉｔｉｏｎ (2 ) ,…