جستجوی مقالات مرتبط با کلیدواژه "finite" در نشریات گروه "شیمی"

This research aims to provide a model to investigate the impact of some parameters such as impeller speed, temperature, and solid concentration on mass transfer coefficient and the dissolution rate of urea fertilizer in the water. To study the effect of solid concentration two models are presented for finite and infinite-volume fluids using mass balance. Then the urea-water mass transfer coefficient was calculated at various impeller speeds and temperatures by measuring the time to complete dissolution. To investigate the effect of impeller speed and turbulence on the mass transfer coefficient, the impeller speed and Reynolds number were set in a range of 10-50 rpm and 300-3000, respectively. The Schmidt number also was used to study the effect of temperature on the mass transfer coefficient in the range of 5-25 °C. The results show that in both finite and infinite fluid volumes, at a constant impeller speed with decreasing Schmidt number, and at a constant temperature with increasing Reynolds number, the mass transfer coefficient, and mass transfer rate increase. Furthermore, four models are presented for mass transfer coefficient in finite and infinite volume, which that shows the mass transfer coefficient and release rate in finite volume were lower than that of infinite volume at a constant impeller speed and temperature.

In this paper, numerical results obtained and explained from an exact formula in relation to sound pressure load due to the presence of liquid inside the finite-length non-rigid carbon nanotubes (CNTs), which is coupled with the dynamic equations of motion for the CNT. To demonstrate the accuracy of this work, the obtained formula has been compared to what has been used by other researchers. For this purpose, the solution of the modified complex Helmholtz equation was derived by considering the non-rigidity of the CNT and the wave reflections at the open ends of the CNT for three different liquids with or without considering the relaxation time. The results showed that neglecting the non-rigidity of CNT would cause a decrease on the pressure fluctuations and the pressure associated with the viscosity force of the liquid in the liquid-filled CNT, at both axi-symmetric, and asymmetric cases. Also, it is showed that the viscous liquid in a CNT is a dispersive medium for sound wave propagation and ignoring the energy loss in the liquid in the high frequency analysis and ignoring the non-rigidity of the CNT would cause errors in the prediction of the sound pressure load exerted on the finite-length liquid-filled CNT