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magnesium-carbonate
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An Investigation into the Microstructure and Mechanical Properties of Biodegradable Magnesium Alloys Composite-carbon Nanotube Produced by the Mechanical Alloying and Powders Pressing Processes
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
Properties of biomaterials, especially in application as planting, can be controlled and optimized by alloying and hardening sedimentation. In recent years, the study on the simultaneous improvement of mechanical properties, toughness and corrosion behavior of magnesium composite by carbon nanotubes (CNTs) is very limited. In this study, the behavior of mechanical properties and corrosion of magnesium alloy composites with different percentages of CNTs have been investigated. The production of magnesium alloy composite by powder metallurgy and aging process have been used as effective methods for improving mechanical properties and increasing the corrosion resistance of magnesium alloys. For...
An Investigation on Production a Biomedical Mg Alloy-carbon Nanotube Composite Using Mechanical Alloying, Sintering & Hot Equal Channel Angular Pressing Process
, M.Sc. Thesis Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
Nowadays, the research of biodegradable alloys with high corrosion and strength properties, along with a modulus of elasticity close to that of bone tissue, especially the magnesium alloys, which has a good biocompatibility and can be used as a biomedical material, has been considered by the medical industry. On the other hand, carbon nanotubes have been used as an reinforcing phase in composites due to their high mechanical properties. The aim of this project is to produce a biocompatible composite with magnesium alloy and carbon nanotube by powder metallurgy. In order to achieve this, first the raw powder of the alloying elements in the matrix without reinforcement and then with weight...
Study on Factor Involved in Multi-step Two Phase CO2 Sequestration Process
, Ph.D. Dissertation Sharif University of Technology ; Shaygan Salek, Jalaloddin (Supervisor) ; Kariminia, Hamid Reza (Supervisor)
Abstract
The increase in CO2 concentration and its effect on ecosystem and global warming make carbon sequestration inevitable for now and future. Ex-situ carbonation of mineral ores is one of the studied sequestration methods. This method is permanent and safe in comparison with others. This process is carried out in four steps and two phases in this dissertation. At the first stage magnesium was extracted from its mineral silicate ore (Mixture of serpentine and olivine) by hydrochloric acid (HCl) and was dissolved in liquid phase as ion. After that the resultant leachate of extraction step was purified from unwanted ions extracted from minerals in two steps by precipitation formed by increasing pH....
Mechanistic study of wettability alteration of oil-wet calcite: The effect of magnesium ions in the presence and absence of cationic surfactant
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 482 , October , 2015 , Pages 403-415 ; 09277757 (ISSN) ; Al Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
Elsevier
2015
Abstract
Over 60% of the world's discovered oil reserves are held in carbonate reservoirs, which are mostly naturally fractured. Conventional water flooding results in low oil recovery efficiency in these reservoirs as most of them are oil-wet. On account of negative capillary forces, injected brine cannot penetrate simply into an oil-wet matrix of fractured formations to force the oil out. Wettability alteration of the rock surface to preferentially more water-wet state has been extensively studied using both smart water and surfactants separately. This study aims to study the effects of Mg2+ as one of the most important wettability influencing ions on the wetting properties of oil-wet carbonate...
Solid products characterization in a multi-step mineralization process
, Article Chemical Engineering Journal ; Vol. 252 , 2014 , Pages 210-219 ; ISSN: 13858947 ; Shayegan, J ; Sharratt, P ; Yeo, T. Y ; Bu, J
Abstract
In this paper, we describe a carbon dioxide mineralization process and its associated solid products. These solid products include amorphous silica, iron hydroxides and magnesium carbonates. These products were subjected to various characterization tests, and the results are published here. It was found that the iron hydroxides from this process can have different crystalline properties, and their formation depended very much on the pH of the reaction conditions. Different forms of magnesium carbonate were also obtained, and the type of carbonate precipitated was found to be dependent on the carbonation temperature. Hydromagnesite was obtained mainly at low temperatures, while dypingite was...
Process optimization for mineral carbonation in aqueous phase
, Article International Journal of Mineral Processing ; Vol. 130 , July , 2014 , pp. 20-27 ; ISSN: 03017516 ; Shayegan, J ; Bu, J ; Yeo, T. Y ; Sharratt, P ; Sharif University of Technology
Abstract
Carbon dioxide sequestration by a pH-swing carbonation process was considered in this work. A multi-step aqueous process is described for the fractional precipitation of magnesium carbonate and other minerals in an aqueous system at room temperature and atmospheric pressure. With the aim to achieve higher purity and deliver more valuable mineral products, the process was split into four steps. The first step consists of Mg leaching from the magnesium silicate in a stirred vessel using 1 M HCl at 80 °C, followed by a three step precipitation in reactors in sequence to remove Fe(OH)3, then Fe(OH)2 and other divalent ions, and finally MgCO3 nucleation and growth. Hydrated magnesium carbonate...