Sharif Digital Repository

Because of production of large volumes of Produces Water during oil exploration, it is necessary to purify this water for reuse or discharging to environment. Thus, finding a suitable method for removing contaminations seems necessary. In the present study, removal of soluble and dispersed organic contaminants from produced water by Dissolved Air Precipitation/ Solvent Sublation has been studied. Combination of floatation by dissolved air and extraction with solvent has been used for removal of organic compounds in order to study simultaneous effect of both methods on removal efficiency. Samples used in the experiments were tested in two groups: the first group was synthesized samples of... 

Green tea has been receiving significant attention in recent years due to its high content of catechins; Epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and especially epigallocatechin gallate (EGCG). As powerful antioxidants, these compounds are believed to have several health benefits. In this study, we used supercritical CO2 with ethanol as co-solvent to extract catechin derivatives from green tea and we investigated the effects of experiment parameters on the extraction. Experiments, designed according to Taguchi algorithm, were conducted with green tea particles of four average diameters of 1500, 855, 605 and 427.5 µm, in an interval of 35- 55 ̊C for temperature and... 

In this work we intend toeconomically recovery of residual from terephthalic acid production unit in the Tondgooyan petrochemical company. Major component of this residual is catalysts, benzoic acid and amount of terephthalic acid product. Catalysts contains of cobalt, manganese and bromide which recycled by water extraction. Effective variable on extraction process is dilution ratio of water to residue, extraction temperature and time. Optimum condition of catalystsrecovery consist of dilution ratio of water to residue 6:1, extraction temperature and time is 45 C° and 40 minrespectively. Recovery yield of cobalt, manganese and bromide in this optimum condition is 91.21, 91.89 and 92.53... 

In this project we focused on Ultrasonic waves as novel, effective and well-controllable means for cell wall disruption and disintegration to provide faster and more complete penetration of solvent into cellular materials and improve sugar mass transfer and extraction from sugarcane and sugar beet. Impact of frequency, temperature, power density and reactor shape on Ultrasonic wave efficiency in extraction process has been investigated and the result was utilized to design a semi-pilot reactor. In the optimum situation, sucrose extraction from sugarcane improved to 4.51 gr/100 ml H2O that had a significant increasing from 2.1 gr/100 ml H2O extraction in thermal only process at 70 °C. Optimum... 

Nuclear energy is one of the most important sources of energy from the economical point of view and also in terms of cleanliness and safety. Hence, strategically, uranium is one of the most basic elements of the earth and nowadays, the importance of this element is more marked due to the nuclear industry developement. Therefore, uranium recovery from the wastes generated during nuclear fuel production in Isfahan’s uranium conversion plant- in which yellow cake is converted to uranium hexafluoride- is quite pivotal. In this experimental research, we have to remove Fluoride from waste after dissolution by several methods like precipitation. After that uranium is extracted from the sludge of... 

In this study, different stages of biodiesel production from microalgae were investigated, specifically the extraction step.Various cultivation methods were also studied among which cultivation under stress was the best. Different carbon sources were also investigated to achieve highest growth. Sodium acetate with complete growth was achieved after 8 days with 6.22% fatty acid recovery. Different mixtures of solvents were compared with Blye and Dier method. Results showed that the mixture of hexane and methanol with crude lipid extraction of 15% and fatty acid recovery of 3.97% were chosen as the solvent mixture of equilibria experiments.Organic solvent composed of hexane (non-polar... 

Separation and identification of metal nanoparticles in surface water samples such as river water is very important. Nanoparticles specially metal nanoparticles have small dimensions can easily pass through from the body's outer immune system and disrupt biological function. Most of the nanoparticles have active surface so environmental contaminants can be absorbed on their surface and then can penerated in the body, and they may cause disease. Therefore determination of nanoparticles type and concentrations and their separation from the surrounding environment, especially surface waters is important. Separation and preconcentration of metal nanoparticles was done by using cloud point... 

In this project, tomato processing waste has been considered as a raw material for bio-refinery applications. Some products from tomato wastes that are usable, economical and environmentally friendly have chosen after lots of studying on researches in regards of producing valuable materials from tomato waste. I’ve used “Superpro designer” software for economical evaluation and determining the possibility of this practice for industrial applications. Beside the tomato paste factory, the process includes one unit of Lycopene production. In addition to Lycopene production, it is possible to produce fertilizer from residues and using them as livestock food or producing energy for the output... 

In this research, experimental study and modeling of biodiesel production process from microalgae has been investigated. First, to have a biomass with suitable lipid content, a novel two-step process based on cultivation under nutrient sufficient followed by cultivation under nitrogen starvation condition has been proposed. Then the effect of using different organic and inorganic carbon sources on this process has been investigated which the results indicated that sodium acetate had a better performance compare to other carbon sources. In the following, the effect of using different light regimes on growth rate, lipid content and fatty acid composition have been investigated. Experimental... 

Uranium recovery from wastes produced in every stage of nuclear fuel cycle is very important from both the economic and environmental points of view. Zircon, zirconium-containing ore that is the input feed to Zirconium sponge production factories, contains considerable amounts of uranium compounds. The majority of this uranium will enter to the different waste streams of the plant. In this study, by analyzing the waste streams of the Zirconium Production Plant (ZPP) located at Isfahan, Iran, total mass balance of uranium in waste streams was identified. It was concluded that bottom residuals at furnaces of the chlorination unit is the primary uranium-containing waste stream. The preliminary... 

To update Blockchains, a consensus protocol must be used to verify the integrity of registered transactions by users. Bitcoin, as the largest Blockchain network, uses a Proof-of-work mechanism to reach consensus and rewards users for doing so. This will lead to the use of costly hardware to execute heavy processing commands with a lot of energy loss. Different groups have since proposed different mechanisms for reaching consensus without costly processing. The idea we present here is that we first define a general chance variable for each miner, and the miner has to wait a certain amount of time accordingly and then be able to generate the block. Chance variables are public, so other members...