Sharif Digital Repository

A significant amount of research in self-consolidating concrete technology is being placed in evaluating the suitability of the material for use in structural applications. However, research is needed to confirm the ability of self-consolidating concrete structural elements to adequately resist vertical and lateral loads. In a reinforced concrete building subjected to earthquake type loading, the beam to column connections constitute one of the critical regions and they must be designed and detailed to dissipate large amounts of energy without a significant loss of stiffness or strength. In the experimental part of this study, four full size interior beam-column subassemblages with 3.0 m... 

Asphaltenes are a polydisperse mixture of the heaviest and most polarizable fractions of the crude oil. They are defined according to their solubility properties as being soluble in aromatic solvents but insoluble in light paraffin solvents. Asphaltenes are usually responsible for many problems like wettability changes of the reservoir rock, pore clogging in the reservoir porous matrix and fouling in wellbore tubing and production surface facilities. Most of the studies in the literature, addressing the asphaltene precipitation and deposition (APD), are investigating natural depletion or gas injection process such as CO2 flooding. These studies show that asphaltene deposition and... 

In this study, electrochemical oxygen reduction reaction (ORR) was studied on Cu, Pd, Rh, Pd-Cu and Rh-Cu alloys in alkaline solution. Pd-Cu and Rh-Cu alloys were prepared by electrochemical methods. On copper electrode it is found that direct oxygen reduction is accompanied by the electrochemical reductions of copper oxides. Also, mechanism and kinetics of reaction change as the amount of copper oxides increase on the surface. For electrodeposited alloys, it is indicated that the reactivity of Pd-Cu and Rh-Cu alloys toward oxygen reduction is higher than pure Pd and pure Rh. The maximum reactivity among Pd-Cu alloys is related to the sample with 24.5% copper content while the maximum... 

Cavity Quantum Electro-Dynamics (CQED) in Weak, Strong and Ultra-Strong coupling Regimes are studied. A MATLAB m-file is written which is able to solve any arbitrary CQED configuration. This program demands input data such as number of Quantum Dots, number of energy levels of each Quantum Dot, energies of each energy level of Quantum Dots, Number of cavity modes, eign-frequency of each cavity mode, coupling constant, dipole strength of each allowed transition of Quantum Dots and initial state of system from user and begins to solve the Schrodinger equation for annihilation and atomic ladder operators. In addition, coefficients of each possible ket will be calculated. Since, any approximation... 

Strongly correlated materials are kind of materials in which novel electric and magnetic properties will appear as a result of strong correlations among their electrons like “heavy fermion materials”. Kondo lattice model is a model to describe heavy fermion materials. If we are merely interested in the magnetic properties of heavy fermions we can replace the Kondo lattice Model with the simpler model called the Kondo-necklace model which consists of the interactions only among the spins of the itinerant (conduction) and localized electrons (magnetic impurities) and also the interactions between the spins of the itinerant electrons. In this thesis we investigate the properties of the one... 

In this study a new Ni(II)-¬oxazoline complex was synthesized by reaction of Ni(CH3COO)2.4H2O and 2-(2׳-hydroxyphenyl)-2-oxazoline ligand in MeOH solvent. The resulting complex bis[2-(2׳-hydroxyphenyl)-2-oxazolinato]Ni(II), was characterized by different spectroscopic methods. X-ray diffraction showed that this complex is four coordinated with a square planner geometry. The complex was applied as an efficient homogeneous catalyst in C-C coupling Heck reaction of arylhalides with olefins such as methylacrylate. Investigation of the catalytic activity of the complex in Heck reaction between arylhalides and olefins showed high yield and selectivity. For example reaction between iodobenzene and... 

Given the complex structure of electronic waste and the difficulty of recycling it by traditional methods, the focus is mainly on biohydrometallurgy method, and in particular on bioleaching. To recover metals, various microorganisms are utilized in this method. In light of previous studies, cyanogenic bacteria have been widely used for the extraction of basic and precious metals. Among the species, indigenous microorganisms have a higher ability to resist toxic environments in the bioleaching of metals due to their adaptation by rapid changes in their metabolic system over time. The main objective of this study is to isolate indigenous microorganisms from electronic waste landfill for their... 

This study investigates the effect of titanium dioxide and magnesium oxide additives on hydroxyapatite synthesized by sol-gel and composite with the predominant phase of hydroxyapatite by in situ method to improve mechanical properties. Scaffold samples were synthesized with nanometer-sized hydroxyapatite and composite powder particles by gel casting and sintered at 1200 ° C. Then, to evaluate the synthesized powders, simultaneous thermal analysis (STA), X-ray diffraction test, FTIR test, FESEM, EDS, and MAP analysis were used. Also, to evaluate the mechanical properties of the scaffolds, a compressive test was used, and to evaluate the scaffolds' density, the Archimedes method was used.... 

Due to the prominence of the evaluation of the consequences of rising temperatures, this paper examines the effects of temperature variation on mortality across different demographic groups in Iran. I use a rich weekly data set from 2009 to 2017 across different demographic groups to understand the potential health impacts of climate change in a developing country. Using several fixed effect regressions, I discover that for an additional day with a mean temperature over 25°C, mortality rate increases by 2.56% relative to the effects of an extra day in 0-5 °C, in the weekly temperature exposure horizon. I test for the harvesting effect by comparing the estimates at weekly and monthly... 

One of the main purposes of this study is to present a robust and yet efficient semi-discretized algorithm for compositional simulation. All the equations including both the mass balance and the phase equilibrium equations are solved simultaneously which forms a Differential-Algebraic set of Equations and is solved by utilizing an efficient MATLAB solver. Furthermore, another formulation and algorithm is proposed which is consisted of two sets of equations, the primary equations (differential mass balance equations) and the secondary equations (the algebraic phase equilibrium equations). The gradient terms in the primary equations are discretized by using finite element method (Galerkin... 

One of the main purposes of this project is to propose an efficient and stable algorithm of a semi-discretized formulation for compositional simulation of oil reservoirs. In this algorithm, all the equations including both mass balances and equilibrium equations are solved simultaneously. The gradient terms are discretized by the Finite Volume Method (FVM). The resulting Differential Algebraic Equation, the so-called DAE, are solved by MATLAB functions. Another novel technique developed, handles each block equations set, separately. In this block-by-block scheme, there are two set of equations; the primary (mass balance) and secondary (equilibrium) equations. In the primary ones, the... 

As the reservoir matures, especially in fractured reservoirs, oil production is usually accompanied by the production of some unwanted water. Water production causes environmental problems and imposes high costs on the production system, including the cost of separating water and oil, corrosion of facility, and sometimes, leading to abandoning well. One way to solve this problem is to use gels as a blocking agent. Today, preformed particle gels are used as an alternative to in situ gels, which can solve some issues of in-situ gels, such as uncertainty in gelling time and penetration depth.This research comprises three main parts. In the first part, four samples of preformed particle gels... 

Low salinity water flooding (LSWF) as an efficient enhanced oil recovery (EOR) technique is proved to affect both, fluid-fluid and rock-fluid interactions to potentially release the trapped oil from the porous rock. Despite more than one decade of extensive research works on the low salinity water effect (LSWE), there are still many parameters to be studied for very complex cases. Therefore, in the first part of the experimental study of the dissertation, a systematic investigation on the effect of the initial wetting state (water-wet or oil-wet) of pure calcite is conducted to study the importance of fluid/fluid and fluid/rock interactions for LSWE investigation. In the case of initially... 

Major parts of Iran's oil reservoirs are fractured carbonates, which need time to produce oil due to their much lower permeability than sandstone reservoirs. Molecular diffusion mechanism is an efficient mechanism in oil recovery from fractured reservoirs under gas injection conditions. The main subject of this work is to investigate the role of molecular diffusion mechanism in the non-equilibrium gas injection project and its role in increasing the oil recovery rate in two southern fractured reservoirs located in the west of Iran, taking into account the capillary pressure, as well as the change of interfacial tension closely miscible conditions is also investigated through simulation. The... 

Equal Channel angular pressing (ECAP) is one of the most applicable Severe Plastic Deformation (SPD) Procedures which results in improvement of strength and ductility through grain refinement and an appropriate texture development. In this study, in order to achieve a proper orientation and microstructure, ECAP was performed in different routes and temperatures up to 4 passes on AZ31 magnesium alloy. Microstructure and mechanical properties were studied. X-ray diffraction analysis was performed to study the basal orientation variation and calculation of sub-grain size. In addition, cold rolling at room temperature was done on the fourth pass specimens, in order to study the effect of ECAP... 

In this research a no-wait flowshop sequence dependent setup time scheduling problem with weighted earliness-tardiness penalties as the criterion (F_m |nwt,S_ijk |∑▒〖w_j^' E_j+w_j^" T_j 〗) is investigated. It is assumed that n jobs are assigned to a flowshop with m machines. The jobs are not allowed to wait between two successive machines according to no-wait requirement. Moreover each machine needs a setup time before processing a new job. The value of this setup time is dependent on the previous processed job on that machine.
A mixed integer linear programming model is proposed to solve the problem. As the problem is shown to be strongly NP-hard, a particle swarm optimization (PSO)... 

One of the most important issues that an organization faced with is resource management. The proper resource management has the great rule in organization cost reduction. One of the most efficient processes in resource allocation is auction and there is different auction with different mechanism and goals. In an auction there is a set of items and a set of bids, and the task of auctioneer is matching items with suitable bids. Each bid consist of desirable items and the bidder value of that items. In an auction process, after mechanism design of auction and auction implementation we must identify the winners of auction and this is a hard problem even in simple auction.
In this study we... 

In this work, inertial guidance and control of an axisymmetric flying vehicle with a spinning part is performed based on dynamic modeling and seven degree of freedom simulation. Flying vehicle is composed of front and aft bodies and these bodies are connected to each other via a hydrodynamic bearing. Front body is roll isolated from the aft body and includes all necessary guidance and control equipments such as sensors, canard set and so on. The control fins, located on the nose, is used to control the roll angle of the nose and to execute the lateral acceleration commands. Also, the aft body is freely rolling and includes the stabilizing fins. In this project, the translational and...