Sharif Digital Repository

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.... 

Man’s struggle for optimization in different areas has been an endless one. Optimizing methods of cancer treatment is not an exception. Because of numerous side effects of anti-cancer drugs, drug delivery systems (DDS) have been recently given much interest. Considering some aspects, DDS are helpful in reducing harmful effects of anti-cancer drugs and more efficient healing by these drugs: first by reducing the dosage of drug by controllable and sustainable release of drug in a kinetic (diffusion) pattern; second by smart release of drug in target tissue which in turn protects sound tissues not to be in contact with drug.In this study, three kinds of nanoparticles have been used for DDS... 

Proteins are of fundamental importance for life on Earth and participate in virtually every process within cells. The function of a protein depends on its three dimensional structure. If this is disrupted, the protein loses its biological activity. In addition to temperature, pressure and ionic strength, pH is also an important factor that affects the configuration of proteins. Proteins contain acidic and basic residues. Variations in pH lead to changes in distribution of atomic charge, which in turn affect the stability and function of proteins. Protein folding occurs in a specific pH range, a deviation from which may facilitate misfolding or Amyloid aggregation. It is therefore necessary... 

Particle reinforced aluminum matrix composites have considerable attraction in automotive and aerospace industries due to their special properties as light weight, high ratio of strength/density, improved elastic modulus, low coefficient of thermal expansion and high wear and corrosion resistance. Among the production processes of metal matrix composites, accumulative roll bonding process has particular importance due to producing ultrafine grained composite sheets. However, uncontrolled and undesired agglomeration of particles is the main problem in producing these composites. In this research, the Al2O3 and SiC nanoparticles were electrostatically stabilized against agglomeration by... 

In this work, a novel type electrode based on RuO2 nanoparticles-modified vertically aligned carbon nanotubes (RuO2/MWCNTs) was investigated. ThisRuO2/MWCNTs electrode not only shows a high capacity nature,but also possesses a good response to the pH value. In order to develope this sensor, aligned carbon nanotubes were synthesized by the chemical vapor deposition at first and then modified with RuO2 nanopartcles by sol-gel method. Various parameters affecting the growth of nanotubes, such as substrate type, surface finishing, surface roughness, the growth temperature and carbon feed rate was studiedand and optimal conditions for growth were obtained. At last, aligned nanotubes with a... 

TiO2 is one of the most frequently used photocatalyst materials. Porous TiO2 nanostructure has drawn much attention recently due to high decomposition rate of organic pollutants. In this thesis, TiO2 nanoparticles were synthesized via sol-gel method and were coated on cotton and jute fiber separately; besides, the impregnated fibers were heat treated to eliminate cellulose. Titanium tetraisopropoxide (TTIP) was used as a precursor and two solutions, acidic and alcoholic, were used as the primary solutions for synthesis. In acidic solution, the crystalline phase and size distribution of TiO2 nanoparticles were evaluated with changing pH.Then, the appropriate pH was chosen for coating. In... 

In this project, function of anaerobic digestion of organic waste in liquid phase and treating the following sewage in biologic tower(trickling filter) has been investigated in an experimental process. Solid waste were supplied from sharif university restaurant and after weighting and classification is added to tanks which filled by 40% sludge and 60% water. For controlling the function of biologic tower, a control reactor were used. Retention time for digestion of solid waste is 40 day. First solid loading was 500g and 75g organic waste in main & control reactor equal to 5(kg solid waste)/( m^3.reactor.day) 1.3(kg TS)/( m^3.reactor.day) and were doubled in second loading. It seems that... 

In this research, we have studied optimization of culture medium and process factors for high alkaline protease production from Bacillus subtilis ATCC 6633 for detergent usage. Five parameter soy bean meal, initial pH, agitation rate, MgSO4, CaCl2 were selected for more studies. At first, one-factor-at-a-time method was applied to investigate effect of each factor separately. Then, optimum condition for maximum protease production was achieved using Minitab software Box-benhnken procedure. According to results, high protease production was seen in soy bean meal, 35 (g/L); MgSO4, 1 (g/L); CaCl2 , 1.5 (g/L); initial pH, 7; agitation rate, 150; inoculum ratio, 12% (v/v). The activity of the...