Sharif Digital Repository

This research work deals with application of poly-saccharide to improve coating process of bioactive ceramic composite on aNd-Fe-B magnetic alloy substrate. Bioactive glass particles were synthesized through a sol-gel process and coated in the form of composite with poly-saccharide onto a magnetic substrate by electrophoretic deposition technique. Stable suspensions of 0.5 gr/lit polysaccharide polymer-ceramic were prepared using bioactive glass particles (<1µm), acetic acid 1%. The influence of added water to ethanol, pH and tri-ethanol-amine (TEA) additive on suspension stability, deposition rate and coating’s structure was investigated. It was shown that by increasing the water to ethanol... 

This study aims to design and develop procedures, forms, and tools for post-earthquake reconnaissance. The current procedure for data collection is based on the sending of groups to identify the dimensions of the evidence and its consequences by the executive and responsible institutions. Studying and reviewing the reports that have been produced by this method shows that there is not any systematic mechanism for collecting data on a wide scale and from all aspects of the evidence. The limited data collected by the executive and responsible institutions are scattered in the reports and are less documented in the database. Therefore, it is necessary to collect big data on the severity and... 

In this thesis, by focusing on the hydraulics of three phase flow in vertical tubing to investigate asphaltene deposition problem, the solid particles behaviors in a turbulent flow is fully studied. Reasonable size distribution for particles (based on previous works and researches) was assumed and a model for 2 sections of a Marrat oil field well to evaluate their asphaltene deposition problem was developed. Three phase liquid-gas-solid flow in the well tubing was simulated. Asphaltene deposition profile on the well tubing, mean and maximum of the deposition rate and particle concentrations in the flow regime were calculated and compared with real field data. Better agreement with field data... 

Structures which are designed in accordance with previously used design codes are usually weak to sustain dynamic loading and therefore they shall be rehabilitated. One approach for rehabilitation is to use active control. In this study, active tendon is used as a structural device control. Various arrangements of controllers can be used to limit the response of the structure but it is desired to find an arrangement at which the cost of the placement will be minimized. The aim of this thesis is to find the best placement of active tendons on a frame such that the placement satisfies two general restrictions; namely structural response and control forces. Genetic algorithm is applied to the... 

Nowadays, the population growth and industrial development have caused pollution of air, water, and soil, which this turned into in a global challenge. Thus, replacing the running-out fossil fuels with renewable sources of energy is an important issue facing research and scientific communities. One of the methods to generate clean energy is hydrogen production through water splitting reaction inside photoelectrochemical cells using an appropriate semiconductor. Upon the light illumination, rates of charge transfer and recombination in semiconductors heterostructure (as photoanodes) are determining factors for efficiency of these cells. If electron transfer occurs faster (in a shorter time... 

consumption of which (especially azo dyes) have been increasing nowadays, causing the increase of textile wastewaters. Usually, these wastewaters contain an immense number of dyes, and if these dyes release in the environment especially in waters, they cause some problems, such as the change of watercolor as well as taste, and affect creatures' lives severely. Moreover, If the dyes are left untreated in aquatic ecosystems, they can remain in the environment for a very long time, resulting in harmful and irreversible effects. Azo dyes are classified as mono, di-, three, azo dyes due to their bonds. Because dyes are increasingly used, nowadays, different methods are developed for the treatment... 

In this study, the effects of parameters such as operation pressure, concentration of Pb2+ ion, nature of associated anion, pH of initial feed and composition of feed was investigated by commercial polyamide nanofilter membrane. One-salt solution nanofiltration experiments was performed by using Pb(NO3)2, PbCl2 and PbSO4 and the binary-salt solution experiments was conducted by using Cu(NO3)2, Cd(NO3)2, Zn(NO3)2, NaNO3 and NH4NO3 together with Pb(NO3)2. The binary-salt experiments in presence of monovalent and divalent cations (together with Pb2+) were performed successively. At first the surface charge of membrane in contact with 1mM KCl solution at pH range of 3-7 was measured. The pH of...