Sharif Digital Repository

In this research, initially the Glycerol liquid membrane with dissolved sodium carbonate carriers, which is supported by CA porous filter, was prepared. The effects of Na2CO3 concentration and pressure difference on gas permeability were investigated. Permeability of CO2 and N2 were measured at pressure difference of 0.7, 1.6, 2.1 and 2.8 bar with carbonate sodium concentration of 0, 1 and 2 mol/lit. Permeability of CO2 was found to be higher than N2. Increasing the pressure difference resulted in an increase in the N2 permeability coefficient while decreased the CO2 permeability coefficient. Increasing the concentration of sodium carbonate increased the CO2 permeability drastically but... 

The application of wet cooling towers is cooling the circulating water which in many processes extract the exess heat in the system. Any cooling tower involves different parts and one of these parts is packings. The effect of changing packing's charactorizations on the cooling tower's performance is significant and was studied in different researches. In this project the effect of packing roughness on the heat transfer, mass transfer and pressure drop in two arrays of packings and in different conditions of water flow rate, air flow rate and inlet water temperature was studied experimentally. For calculating and investigating the change of mass transfer coefitient, the Poppe model was ... 

In liquid-liquid extraction, as in gas absorption, two phases must be brought into good contact to permit transfer of material. The presence of nanoparticles in liquid phase can enhanced the rate of gas-liquid mass transfer. The benefits of nanofluids can be used to enhance the heat and mass transfer of liquid-liquid extraction. Standard test system with low interfacial tension that recommended by EFCE: n-butanol/water/succinic acid, was used in this project. The CNTs/n-butanol that was saturated of water used as dispersed phase. Water and succinic acid used as continuous phase and solute. Since there is no chemical reaction to take place between CNTs and n-butanol, In order to obtain well... 

In this project, the continuous phase mass transfer and backflow coefficients are optimized, using the experimental data from two RDC columns. The continuous and dispersed phases are modeled by stage wise and forward mixing model, respectively. Genetic Algorithm is applied to find the optimized parameters of the model. Olney model is employed to find the slip velocities of drops. The dispersed phase mass transfer coefficients were calculated using Handlos-Baron model. In the other part of the project, the Rigid Drop model was modified to predict the mass transfer coefficients of dispersed phase and the modification parameter was optimized by genetic algorithm. The effect of rotor speed and... 

CO2 separation from air was investigated in this work. An immobilized liquid membrane (ILM) which contains triethylene glycol (TEG) and diethanolamine (DEA) was used for this purpose. In this kind of membranes a liquid, which improves permeability of gas species through the membrane, fills the pores of a polymeric membrane as support. Because of low vapor pressure of solution, liquid loss was negligible. Transport of CO2 was facilitated due to reversible chemical reaction between CO2 and amine solution. A polyvinylidene fluoride (PVDF) membrane was chosen to have chemical resistance against the solution and prevent destruction of polymer by solution. A flat sheet and hydrophilic PVDF was... 

In this research, initially the Triethylene glycol and Diglycol amine liquid membrane which is supported by PVDF, was prepared in order to separate the Carbone dioxide from CO2-Air mixture. A polyvinylidene fluoride (PVDF) membrane was chosen to have chemical resistance to solution. The effect of Pressure, Concentration of TEG and DGA solution and the percentage of carbon dioxide in feed; in rate and permeability of CO2, N2 and O2 and also selectivity of CO2/ N2 , CO2/ O2 and N2/ O2 was investigated. Transport of CO2 was facilitated due to reversible chemical reaction between CO2 and amine solution. The experiments were done in 0.4, 0.6 and 0.8bar and different concentration of solution.... 

In this research, the effect of feed flow concentration on the separation of gas mixture of carbon dioxide and oxygen was investigated by using supported liquid membrane in the presence of nano particles. In order to achieve this purpose, supported liquid membranes were prepared by impregnating a porous hydrophilic PVDF support with TEG, cyclohexanol, TEG/Fe3O4 nano particles and cyclohexanol/ Fe3O4 nano particles. Permeability and selectivity of mixed gases CO2 and O2 were examined at five different CO2 concentrations in feed flow, constant feed flow rate and constant total pressure difference.
In all tests, the permeance of carbon dioxide through cyclohexanol and TEG membranes was... 

In various industries, for energy production, fossil fuels are burned. Oxygen needed for combustion, taken directly from the ambient air; So that the inert gas is about 80%. The presence of this inert gas, mainly nitrogen, reduce combustion efficiency and increase the use of combustible material. In this project with the help of membrane technology, was used to remove the amount of nitrogen in the air so that the incoming air into the combustion chamber is enriched with oxygen. For this purpose, several gas separation membrane was applied and evaluated. Then, according to the oxygen enrichment, fuel efficiency and the amount of savings, increasing chamber temperature, reduction manufacturing... 

In the present study, a heat recovery system for a distributed generation plant (DG) with a 1 MW gas combustion engine has been designed. The purpose of this designing is converting the power plant to a CHP system. For the existing heat recovery system, a shell & tube heat exchanger is designed to recover the thermal energy from exhaust gases and a plate heat exchanger is designed to recover the thermal energy from the engine jacket cooling fluid. The heat exchanger design has been calculated manually and also by use of software. In the software calculation, the heat exchanger design has been done by use of the Aspen HTFS +2006.5 software. In the manual one, the Kern equation (1950) was... 

The main objective of this project is to study the effect of the presence of nanoparticles on mass transfer in liquid-liquid systems. To do this research, TiO2/water, Al2O3/water, CNTs/water and CNTs/toluene have been used as nanofluids. The experiments of TiO2/water nanofluid were been carried out in water-acetone-toluene system at two weigh percents of TiO2 nanoparticles. The result showed that mass transfer decreased in 0.5wt% of TiO2, compared to base fluid, and it increase in 1 %wt. Also in 0.5%wt the decrease in interfacial tension decreased diameter of drops and as a result mass transfer decreased too. In 1%wt the increase in viscosity increased the diameter of drops and then the... 

Employing array of antennas in amny signal processing application has received considerable attention in recent years due to major advances in design and implementation of large dimentional antennas. In many applications we deal with such large dimentional antennas which challenge the traditional signal processing algorithms. Since most of traditional signal processing algorithms assume that the number of samples is much more than the number of array elements while it is not possible to collect so many samples due to hardware and time constraints.
In this thesis we exploit new results in random matrix theory to charachterize and describe the properties of Sample Covariance Matrices... 

Range Profile (RP) is known as one of the most important tools for radar target recognition. The main problem with range profile for radar target recognition is its sensitivity to aspect angle. To overcome this problem, range profiles are assumed to have the same statistical characteristics in small frames of aspect angles or context dependent models such as HMM may be used. All methods presented, seems to have some shortcomings to offer a model based on physical circumstances of target maneuver. For example in such models, consecutive samples of RPs in an aspect frame are assumed to be statistically independent with the same distribution (IID). Here we propose dynamic system (DS) for... 

Although up to now different processing algorithms have been proposed for Synthetic Aperture Radar (SAR) raw data, all of them suffer from one common problem and that is huge amount of data to be processed. So because of current system limitations, efficient compression algorithms for processing, saving, or transmitting data are needed. Up to now many algorithms have been proposed for SAR raw data compression, but each of them has some defects that should be payed attention to. The most important reason of these defects is the special characteristics of SAR images. With the aid of “Compressed Sensing (CS)”, the new field which has emerged recently, a special characteristic of the scene... 

In present study, it is tried to investigate the effect of physical properties on hydrodynamic and overall mass transfer coefficient of single drops using different experiments and then simulation of drop motion with OpenFOAM software version 1.7.1. the systems were choosen are toluene/acetone/water and n-butanol/succinic acid/water which their interfacial tensions are 36 and 1.6 mN/m respectively. Various type of nozzles have been used for produce of 1.5, 2, 3 and 4 millimeter drops. The results show that in absence of solute component, the rising velocity of toluene drops in each size is higher than rising velocity of butanol drops inside the water between 25 to 75 percent. But with... 

Mass transfer and axial dispersion coefficients for continues phase were calculated by axial mixing model for continues phase and forward mixing model for dispersed phase simultaneously. Experimental data was achieved in pulsed sieve plate column with 22 cm diameter. Toluene –water-acetone and Butanol-Succinic acid- water were used in this experiment. In these systems continues phase is water and mass transfer takes place from continues phase to dispersed phase. Experimental data involves drop size distributions and operating conditions andconcentration in both phases.For calculating overall mass transfer coefficient for drops the handlos and Baron Model was used. The axial dispersion...