Sharif Digital Repository

Concrete Filled Polyvinyl Chloride (PVC) Tube (CFCT) technique has attracted significant research attention in recent years. PVC offers a number of advantages such as low costs and excellent properties like 1- high electrical insulation; 2- high resistance for abrasion; 3- low diffusion for humidity; 4- remarkable resistance to water, bases, acids, alcohols, oils; 5- large elongation at break; 6- low creep deformation; 7- workability including (cutting); 8- consistency; and 9- excellent corrosion resistant, durability and mechanical stability. The PVC tube acts as a longitudinal and transverse reinforcement and serves as a formwork which simplifies construction and reduces erection time. The... 

The Self-Consolidating (Compacting) Concrete (SCC) is a high performance concrete. Due to preventing it from segregation, SCC is known by its need to higher dosage of super plasticizer and viscose modifying agents. This increases the cost and reduces the popularity of SCC in construction industry. In this thesis, the production of Rice Husk Ash (RHA) from a controlled burning process using a special designed furnace, and cement replacement feasibility in the concrete mixture by low cost RHA, as an active pozzulanic additive have been investigated. Finding an appropriate ratio of replacement with cement for RHA and further effects on mechanical properties of SCC have been evaluated. The... 

Growing rate of eutrophication in receiving waters has made the enhancement of wastewater treatment plants to advanced methods of nutrients removal as necessary. Nitrogen and Phosphorus as the nutrients can reduce the quality of water and even make it unusable. Phosphorus is known to be one of the main reasons of eutrophication and creation of algal bloom. In this study, chemical-biological method for phosphate removal from the municipal wastewater is studied. Experiments are implemented for hydraulic retention times of 4, 8 and 16 hours, total intake concentration of phosphorus 7 ppm, COD 400 ppm and Nitrogen 25 ppm. Ferric Chloride as the precipitator chemical substance injected into the... 

Textile industry is one of the biggest consumers of water in the world. Effluents of textile industry ordinarily have huge rate of dye compounds which are toxic and persistent in environment. In case which they did not treat and discharged in the environment, they can create cancer, poisoning and etc. Finding efficient, economic and fast method for treating of these effluents is an important factor on the management. Combination of ultrafiltration membrane and reverse osmosis processes, has taken into consideration as an efficient and fast method of treatment of textile effluents in recent years. One of the fundamental problems of this process is the high costs of operation and chemical... 

This research aims to design and build a device that Using solar energy and can be used as water heaters and water desalination and water from the soluble hygroscopic. For this purpose, a combination of evacuated tube collector with parabolic through collector with sun tracking mechanism is used. sun tracking mechanism is polar and works with optical sensor. in this research we have designed new setup with evacuated tube collector for direct desalination and water heater. in this method heat pipes have been omitted from setup that cause high performance in heat transfer from evacuated tube collector to water and is minimized losses. 15w air compressor used to increased rate of evaporation ... 

Gold is a noble and precious metal used in various industries, including jewelry, electrical and electronic, catalyst, and medical industries. Multiple processes are used to extract and refine gold; each one has its advantages and disadvantages. In this research Work, comprehensive information on the electrochemical purification process of gold from anode electrode with 75% crude gold and titanium cathode electrode in the chloride electrolyte solution is presented. To perform the purification process, first using the parameters and their levels, including temperature (30, 45, and 60 degrees Celsius), voltage (2, 2.2, and 2.4 volts), and acid concentration (1, 2, and 3 M), Design of... 

Today, in our beloved country of Iran and other parts of the world, reinforced concrete structures are used in large industrial projects, in some cases we see their very early failure even before the time of operation. This issue in the southern coasts of the country due to special weather conditions (humidity and high temperature) and the existence of the offensive ions such as chlorine and sulfate in seawater are more important and we always face with severe corrosion of reinforcement and reduced service life of concrete structures in these areas. Despite this, little research has been done on the reliability of concrete facilities in the vicinity of the Caspian Sea in the north of the... 

In this study, the electrochemical precipitation of three-component zinc-nickel-manganese coating on st37 steel substrate from chloride bath was investigated. Cyclic voltammetry results showed that the presence of ammonium thiocyanate complexer had a positive effect on the stability of precipitated manganese. Also, in order to evaluate the optimal coating conditions, the precipitation process at voltages of -1.4, -1.5 and VSCE -6.6, concentration of zinc 0.3 M, concentration of nickel 0.15 M and concentrations of manganese 0.15, 0.3 And 0.45 M and temperatures of 25, 40 and 55 .C. The results of X-ray energy diffraction spectroscopy, atomic absorption spectroscopy and X-ray diffraction of... 

Electric field sensors are one of the common types of sensors that are widely used today to record changes in the electric field in underwater environments, also record pH changes in different materials. This type of sensor is inspired by the shark mucous membrane. In this study, silver / silver chloride silver (Ag / AgCl) was used for three methods of silver filtration directly in electrolyte containing chloride ion, Electrophoretic electrode method and electrode making method using silver oxide adhesive. Part of the electrodes manufacturing method involves converting part of silver into silver chloride. The made electrode has a length of 7 cm and a diameter of 0.5 mm, with its core made of... 

Considering the demand for electronic and other products that rare earth elements are one of the necessary materials for their production, recovery of these elements plays an important roll today.The term “rare earth”, represents a group of 17 metalic elements with similar physical and chemical properties such as Sc,Y and lanthanides. Lanthanides are a group of elements with 57 to 71 atomic numbers and all of them except Pr, are present in earth crust.Some of these elements are available in phosphate concentrate(iron ore waste) of chadormalu in bafgh. Base on the analysis performed on apatite concatrate, it was represented that Ce,La and Nd elements are more than the others. So this research... 

Titanium dioxide is one of the most important first material in many industrial applications and for producing Titanium.Although it was discovered more than 200 years ago and has been commercially processed for 85 years, it is still being actively investigated. So far Iran imports TiO2. But some projects have been planned to produce pure TiO2 from Ilmenite and Titanomagnetite ore. In the present work production of highly purity TiO2 from Ilmenite ore by chloride leaching has been investigated. Chloride leaching has been accomplished by several stages of leaching in hydrochloric acid, reduction, crystallization, hydrolysis and finally calcination of the powder. According to the result... 

High advantages of hydrometallurgy have led to its recent development in metal extraction. Many investigations are being carried out on applying hydrometallurgy processes on copper extraction. In this study, the chloride leaching of chalcopyrite in a concentrated sodium chloride solution (4M) –which is a novel process–, using CuCl2 as leachant is investigated. Main effects and interactions of temperature (50–90°C), time (2–6 hr), CuCl2 concentration (0.1–0.5M), pulp density and HCl concentration (0.1–1M) at constant stirring rate (600 rpm) on leaching is studied using 2k factorial design and applying Design–Expert 7.0.0 software. While the effect of pulp density is almost negligible,... 

In recent years magnesium nanoparticles due to their noticeable differences from bulk and their wide applications in various branches including the ability to absorb hydrogen, application in batteries, activation of propellant, different applications in biochemistry and strengthening secondary phase in composites, are well under investigation. The objective of this study is to find an easy, economical and high purity method to obtain magnesium nanoparticles and to introduce an innovative approach of magnesium nanoparticles synthesis in an industrial scale. To achieve this goal, milling process is applied. Micron-sized magnesium powders with different amounts of sodium chloride salt powders... 

Composite coatings including self-lubricant particles such as graphite, MoS2, Al2O3 and SiC are extensively used to decrease the coefficient of friction of tribo-surfaces. Adding lubricant particles to an appropriate metallic matrix like copper, nickel, lead and their alloys is a suitable option in severe condition –for instance high temperature and low pressure- which liquid lubricants will be failed. Bronze can give various properties such as wear resistance, corrosion and oxidation protection, However cyanide solutions for electroplating process have environmentally limited for plating of Cu-Sn. In this research, a chloride electrolyte for bronze electroplating was developed and effect of... 

In this study, pitting corrosion of 304, 316 and 316L stainless steels in 3.5% NaCl solution at different temperatures (25, 40, and 70°C), were studied by electrochemical methods such as Cyclic Potentiodynamic Polarization, Electrochemical Impedance Spectroscopy and Immersion tests. Also, the effects of different concentrations of polyethyleneimine with two molecular weights (2000 and 60000 g/mol) on pitting corrosion of these steels were investigated. Finally, the adsorption behavior of inhibitors on surface of alloys was investigated by Atomic Force Microscopy (AFM) and Attenuated Total Reflectance Fourier transform spectroscopy (ATR-FTIR). It was found that both inhibitors prevent... 

In this work, carbon nanotubes (CNTs) were synthesized via arc discharge in an aqueous solution. The role of iron catalyst in CNTs formation was investigated utilizing arc discharge in iron salts solution (Fe2(SO4)3 and FeCl3). Thermogarvimetric (TG) analysis showed the presence of multi-layered structures including multi-walled carbon nanotubes (MWCNTs) and multi-shelled graphite particles when processing was performed in DI-water. In the presence of iron ions, single-walled carbon nanotubes (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were formed. The effect of iron ions (Fe3+) concentration on CNTs yield was investigated by Raman spectroscopy. The highest yield was obtained when... 

In this study, for investigation of water salinity effect on asphaltene modeling, PC-SAFT equation of state has been used. All steps of modeling have been done by C sharp programming language software. Nghiem model has been used for modeling of asphalting pure solid. In this model, the heaviest component is split into two precipitating and nonprecipitation parts that their physical properties are the same in each part. Furthermore, to determine the exact mechanism of asphaltene precipitation, an oil model (Asphaltene+heptan+tuloene) in the presence of different water brine such as synthetic brine (with MgCl2, CaCl2, and Na2SO4 salts), seawater) ten and two times diluted), and formation water... 

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... 

Golpayegan Qaed Basir Petrochemical Company is one of the lucrative and entrepreneurial companies in Iran. Every day in this complex, a large amount of wastewater is being generated and transferred to the evaporative lag after the primary and secondary purification outside the complex and it is not restored. Considering the growing importance of surface and underground water resources, reuse of wastewater is a valuable production. In this research, the optimization of the sewage treatment system of the complex was evaluated by replacing the chemicals in the primary purification unit and also by using chloride-ferric and trickling filter for tertiary purification(treating) of the...