Sharif Digital Repository

The goal of this study is to explore the density-driven flow and study the effect of fracture as well as chemical processes and reactions on convective transport. Convective flow is used in connection with the density-driven flow where the flow is driven by density differences in the fluid, which can be affected by the ambient rocks. Several studies of density-driven flow in porous media have focused on the effect of heterogeneity on the mixing convection; however, they neglect the key processes of geochemical reactions in fractured porous media. This study aims to address this gap by investigating the combined effect of heterogeneity (as fractures) and the existing geochemical reactions on... 

The main goal of the research is to formulate and implement the governing equations of Thermo-Hydro-Mechanical (THM) phenomena in fractured/fracturing unsaturated porous media with two-phase fluid flow using the Extended Finite Element Method (XFEM)with phase change consideration(evaporation/condensation). The medium is assumed to be isotropic, and the fluid phases are liquid water, vapor and dry air. The four governing equations are linear momentum equilibrium of the media, continuity equation of water (liquid water and vapor), continuity equation of dry air, and the thermal equilibrium of the medium which are considered to be fully coupled. The fracture is modeled in mode I with... 

Nowadays, due to the increasing importance of environmental issues, cement replacement has been considered by many researchers .Determination of behavioral characteristics and fracture of materials such as fracture hardness and energy is used to describe the formation and progress of cracks in new building materials. On the other hand, one of the concrete that can be replaced ordinary concrete is slag concrete. Slag concrete is in the category of Geopolymer Concrete. This concrete is produced by activation of puzzulanic material by alkaline solution.There have not been many studies on the failure of slag concrete. Therefore, in this study, the mechanical properties of slag concrete were... 

Formation damage in petroleum engineering is an important and fundamental phenomenon. During drilling operation, penetration of either the solid phase of drilling fluid or the base-fluid into the porous medium, reduces the permeability of the formation. While most experiments in the literature have focused on core-scale and beyond, there is lack of pore-scale studies. Moreover, presence of fractures has an undeniable effect on the extent of formation damage. Thus, the main objective of this dissertation is to investigate the effects of fractures on the severity of formation damage caused by the water-based drilling fluid and the mechanisms of formation damage at the pore scale, using glass... 

In this thesis, the strain rise phenomenon and its adverse effect on the deformation capacity of steel elements, members, and connectors were investigated. The high-rate increase in plastic strains was termed strain rise. In this study, the sharp increase in plastic strains and its causes were investigated through conducting experiments and extensive numerical analyses. The causes of strain rise were fallen into two categories as primary and secondary. To limit the adverse effect of strain rise two methods of decreasing the initial stress concentration and expanding the plastic volume were proposed. The strain rise in the saddle and pre-Northridge connections as a result of primary effects... 

In fractured reservoirs under the gravity mechanism, the oil transfer between the matrix blocks is affected by mechanisms such as capillary continuity or re-imbibition. Capillary continuity between adjacent matrix blocks can be created by formation of liquid bridges, or physical contact of surfaces due to the roughness of the fracture wall surface.Since the presence of liquid bridges can be effective in creating capillary continuity and therefore the amount of oil production, the study of the presence of liquid bridges between matrix blocks and how they change in terms of volume and shape in the process of oil and gas movement is of particular importance. Although there are studies on the... 

Nowadays adhesives with the development of technology and the numerous benefits they have, are becoming a replacement for traditional joining methods in industries like electronics, automotive, aerospace, and naval. That’s why the need for studying the fracture behavior of adhesive joints becomes vital. So far, many engineers and designers are trying to investigate the behavior of adhesive joints in different conditions that these joints actually deal with. Also, finding solutions to predict the behavior of adhesive joints is the researchers’ other concern. The purpose of this research is to find the effect of factors that are less focused in the literature, on the fracture of adhesive... 

Nowadays adhesives with the development of technology and the numerous benefits they have, are becoming a replacement for traditional joining methods in industries like electronics, automotive, aerospace, and naval. That’s why the need for studying the fracture behavior of adhesive joints becomes vital. So far, many engineers and designers are trying to investigate the behavior of adhesive joints in different conditions that these joints actually deal with. Also, finding solutions to predict the behavior of adhesive joints is the researchers’ other concern. The purpose of this research is to find the effect of factors that are less focused in the literature, on the fracture of adhesive... 

Dense non-aqueous phase liquid accounts for a large share of groundwater pollution. In oil-rich countries, including Iran, the emission of this type of pollutant is mainly through leakage from concrete and steel tanks belonging to refineries and gas stations. The dissolution of these pollutants in groundwater and the vapor intrusion into residential homes increased the importance of developing efficient treatment methods. To choose the best method, it is necessary to gain sufficient knowledge of how these types of contaminants are distributed in the subsurface and how contaminants change and move over time. Heterogeneity, especially in the form of fracture, is one of the challenges to...