An analytical method is derived for the thermal consolidation of a saturated, porous, hollow cylinder with infinite length. The solutions in Laplace transform space are first obtained and then numerically inverted by Stehfest method. Two cases of boundary conditions are considered. First, variable thermal loadings are applied on the inner and outer pervious lateral surfaces of the hollow cylind...

The paper deals with a very common situation in many control systems and this is the fact that, for zero control action, the controlled variable is nonzero. This is often caused by the existence of another process input which is uncontrolled. Classic controllers do not take into account the second input, so deviation variables are considered or some feedforward controller is used to compensate ...

satellite thermal control ensures safe operating temperature ranges for satellite components throughout the mission life. effects of altitude, spin, and position of satellite radiator(s) on the thermal control of a small low earth orbit (leo) satellite have been studied. results show that change in satellite altitude, in the range considered here, does not produce critical thermal conditions. h...

The effectiveness of a proportional feedback control to suppress the Marangoni instability in a variable-viscosity fluid layer with a deformable free upper surface is investigated. Viscosity variation and deformable free surface have destabilizing effects on the stability limit. The stability thresholds for the short-scale mode are strongly dependent on viscosity variation and controller gain w...

The thermal conductivity of mantle materials has two components, the lattice component klat from phonons and the radiative component krad due to photons. These two contributions of variable thermal conductivity have a nonlinear dependence in the temperature, thus endowing the temperature equation in mantle convection with a strongly nonlinear character. The temperature derivatives of these two ...

In this study, a frequency converter was used to carry out variable frequency control to the compressor with constant frequency of a small 3RT central air-conditioning air-cooled chiller, but the indoor blower and cooled water pump were still kept by constant frequency operation. It is to explore the energy-saving effect of chiller compressor and the cooling fan after being carried out the vari...