Sharif Digital Repository

Scaling transistor size to the scale of the nanometer coupled with reduction of supply voltage has made SRAMs more vulnerable to soft errors than ever before. The vulnerability has been accentuated by increased variability in device parameters. In this paper, we present an analytical model for critical charge in order to assess the soft error vulnerability of 6T SRAM cell. The model takes into account the dynamic behavior of the cell and demonstrates a simple technique to decouple the nonlinearly coupled storage nodes. Decoupling of storage nodes enables solving associated current equations to determine the critical charge for an exponential noise current. The critical charge model thus... 

This study investigated the behavior of ferrofluids containing superparamagnetic iron oxide nanoparticles (SPION) of various compositions for potential applications in drug delivery and imaging. To ensure biocompatibility, the interaction of these SPION with two cell lines (adhesive and suspended) was also investigated using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay. The cell lines studied were primary mouse connective tissue cells (adhesive) and human leukemia cells (suspended). SPION were synthesized with a co-precipitation method under different stirring rates and NaOH molarities. The SPION demonstrated a range of magnetic saturations due to their... 

In this paper an analytical model is proposed to study the nonlinear dynamic behavior of rolling element bearing systems including surface defects. Various surface defects due to local imperfections on raceways and rolling elements are introduced to the proposed model. The contact force of each rolling element described according to nonlinear Hertzian contact deformation and the effect of internal radial clearance has been taken into account. Mathematical expressions were derived for inner race, outer race and rolling element local defects. To overcome the strong nonlinearity of the governing equations of motion, a modified Newmark time integration technique was used to solve the equations... 

This paper a simple semi-analytical model for calculation of the time evolution and spatial variation of the electric field in microring resonators in the presence of The Kerr effect and two-photon absorption (TPA) is presented. The theoretical analysis is based on the delayed feedback model, which is well known in microring theory. The model is applied to the Chalcogenide glass and AlGaAs microrings to study the Kerr and TPA effects on the spatial and temporal variation of electric field respectively across the microring. The effects of microring parameters and input signal shapes on the transient behavior are taken into consideration. It is shown that, the results are in good agreement... 

The liquid-liquid extraction process is well-known for its complexity and often entails intensive modeling and computational efforts to simulate its dynamic behavior. This paper presents a new application of the Genetic Algorithm (GA) to predict the modeling parameters of a chemical pilot plant involving a rotating disc liquid-liquid extraction contactor (RDC). In this process, the droplet behavior of the dispersed phase has a strong influence on the mass transfer performance of the column. The mass transfer mechanism inside the drops of the dispersed phase was modeled by the Handlos-Baron circulating drop model with consideration of the effect of forward mixing. Using the Genetic Algorithm...