Sharif Digital Repository

Hydrodynamic behavior of gas-solid fluidization in large-diameter beds like FCC regenerator exhibits complex aspects. To investigate the gas-solid flow pattern of UOP's combustor-style FCC regenerator, a lab-scale regenerator was designed by a downscale factor of 0.045. The regenerator's operation and fluidization of FCC particles through it was examined and pressure axial distributions were measured and analyzed at different superficial air velocities. 3D CFD simulation of the regenerator was performed with Eulerian-Eulerian approach to investigate the effects of operating conditions, including superficial air velocity, catalyst mass flux, presence of recirculated catalyst, and the... 

Electric motors used in electrical vehicles are varied, but in light electric vehicles such as electric motors and electric bikes, with limited space, permanent magnet motors due to their high power density and efficiency are very useful. These motors are divided into two types: trapezoidal and sinusoidal due to the waveform of the Back EMF voltage. The trapezoidal type, also known as the brushless DC motor , is more commonly used in light electric vehicles due to the simplicity of the control system and the lower cost. The control system of the BLDC motor is very important in its performance. Providing a controller for these engines that at low cost improves their performance is considered... 

Three-phase electronic loads are used to test the performance of various electrical devices such as power supplies, generators, and transformers. Conventional electronic loads are composed of passive components that consume the energy, so have low power density and efficiency and to manage the produced heat, massive cooling systems are required. Nowadays, to increase efficiency and power density, three-phase regenerative electronic AC loads have been developed. To return energy to the grid and control the input power factor, the structure of these loads is based on back-to-back converters. In this project, a 35 kVA three-phase regenerative electronic AC load is designed. To control the power... 

In recent years, it is expected that the fabrication of multilayer scaffolds and the use of different methodologies in one product can be a new progressing method in skin substitute production. Accordingly, this project aims to fabricate a bilayered composite scaffold with a combination of hydrogel and electrospinning method. We have tried to prepare a scaffold made of oxidized alginate (OAL), gelatin (G), and silk fibroin (SF) without using corrosive solvents and toxic crosslinking agents as a scaffold and drug delivery system. As different biological, chemical, physical, and mechanical factors play a vital role in the healing process, we have characterized the proposed scaffold via DSC,... 

Rapid population growth and increasing and rapid consumption of natural resources in the ecosystem leads to the destruction of resources and thus increases the entropy in the earth, and this increase in entropy in the ecosystem changes the environment and has adverse effects on it. As all components in nature interact with each other by action and reaction, therefore, any change in the environment must be adjusted by other sectors and approached a reversible process to enable sustainable ecosystem changes. On the other hand, there is evidence that the world's physical capacity is inadequate to meet the requirements of sustainable development. The reason for this fact is that the ecological...