Sharif Digital Repository

This thesis presents a research on the physical behavior of water inside carbon nanotubes (CNTs). Molecular simulations are carried out using the Monte Carlo method in the canonical and grand canonical ensembles. Due to the difference between the inter-molecular forces in the axial and radial directions, the anisotropic pressure tensor is calculated for water confined inside the CNTs with the diameters of 0.88, 1.08, 1.28, and 1.48 nm at different densities using the Monte Carlo simulations. Using the assumption of effective extended Lennard-Jones interactions between the nearest neighbors, a set of new equations of state for water confined inside the CNTs is derived and shown to be... 

In the present study, Friction Stir Process (FSP) was used to refine the microstructure of pure commercial copper in order to improve the mechanical properties. Since FSP can be considered as a hot deformation process, theoretical Models were utilized to simulate both thermal history and strain rate distribution. Zener-Hollomon parameter (Z) was then utilized to predict the microstructure of Stir Zone (SZ) which undergoes the Dynamic Recrystallization (DRX). Temperature distribution was formulated and solved by a commercial software COMSOL Multiphysics. Strain rate was analyzed using theoretical models and the codes were written by MATLAB. The predicted grain size was not in a good agreement... 

Part 1: Techniques of production data analysis for single-phase oil and gas reservoirs have advanced significantly over the past few years. These techniques range from traditional (Arps and Fetkovich) to modern (they account for the variation of operating conditions at the wellbore). Although the production data analysis methods are used generally for single phase reservoirs, the application of these techniques for analysis of production data of a gas condensate reservoir may not yield the reliable answer due to the fact that the flow of fluid in gas condensate reservoirs is not single-phase. This study presents the treatment of the modern methods of production data analysis (single phase... 

This research studies the feasibility of the BK7 optical glass milling process with ultrasonic vibrations. Due to the fragility of glasses, especially optical glasses, machining is very sensitive and complex. For this reason, it is necessary to think for the glass machiners to minimize the defects and failures of the process. So far, efforts have been made to reduce the defects caused by machining on brittle materials, such as increasing the speed of the period, reducing the feed rate of the tool, changing the geometry and the type of tool, the type of process lubrication, etc. In addition, other operations performed to improve the surface of the glass are of better quality, using hybrid or... 

In today's world, where consumers are increasingly demanding high-quality electricity supply, particularly with minimal outages and the highest continuity of power delivery, considering reliability indices in distribution system expansion planning models is essential. To simultaneously meet the requirements of both economic and reliability criteria for distribution networks, planning models need to assess the reliability of active distribution networks throughout the optimization process. In order to achieve a reliable plan, it is necessary to integrate the reliability evaluation of the network into the distribution planning problem. This thesis presents an effective model for distribution... 

In order to prevent deterioration of metallic interconnects in solid oxide fuel cells (SOFC), while interacting with glass-ceramic sealant, a nickel electroplated ferritic stainless steel (UNS 430) was used. After applying a layer of powdered glass (SiO2-B2O3-Al2O3-Na2O-BaO-K2O) with thickness around 300-450 μm on the ferritic stainless steel sheets with dimansion of 0.5 × 60 × 60 mm and 0.5 × 10 × 10 mm, samples were heated at temperatures between 770-850 °C and durations of 1 to 15 hours. To evaluate the effect of the Ni layer, two types of sample (only sanded and only electropolished) were also submitted to the same process, and their results were compared with the coated samples. XRF,...