Sharif Digital Repository

In this work ionic liquids as the new generation of solvents are studied. First, Ionic liquids are introduced and their applications and characteristics are briefly discussed. Then, one of the most potential applications of ionic liquids in separation process (Aromatic-Aliphatic separation) is studied and compared with the common and alterative separation processes. In experimental section, large amount of 1--ethyl 3-metyl pyridinium ethyl sulphate ionic liquid was synthesized with a purity of above 99%. Experimental studies of separation of toluene from its mixture with n-heptane with the aid of synthesized ionic liquid were conducted and acceptable results are obtained. Experimental LLE... 

The Ranque-Hilsch vortex tube (RHVT) has no moving parts through which a high-pressure fluid gains on rotational velocity by passing radially through the inlet nozzles and then enters the vortex chamber. Subsequently, the high-pressure fluid becomes divided into two relatively distinctive hot and cold axial flows. Today, while RHVT is of great industrial interest due to its simplicity in manufacturing and operation; however, the mechanism of energy dissociation, which is dominated by the complex coupled interaction of the viscous thermo-fluid characteristics and geometrical properties, is not fully understood and no clear theory has been proposed to explain the energy dissociation so far.... 

Cancer diagnosis area has recently been in the limelight of the medical research and there exist an unremitting focus on the devices & technologies which enable cancer detection in its victims. Lately a genius diagnostic method based on isolation and entrapment of circulating tumor cells has been developed which pave the path for cancer identification. These circulating cells which are detached from the primary tumor are carried out through body by means of circulation system. They play key role in phenomenon called metastasis. Separating these rare cells from multifarious background blood cells, assessing their quantity can supply valuable information on the stage of disease as well as its... 

Composite membranes are one of the promising membranes for overcoming the limitations of conventional membranes in gas separation application by improving the permeability and selectivity. However, it is still very challenging to achieve adhesion interface between the top selective layer and the bottom support layer. The present study demonstrates that this challenge can be overcome appropriately by utilizing a series of adhesive polymer as selective layer to prepare composite membrane. To this end, in the first section a series of acrylate-terminated polyurethanes (APUs) based on poly(ethylene glycol) (PEG) with different molecular weights (Mn) of 600, 1000, 1500, 2000 and 4000 g/mol,... 

Nowadays binary sensors such as infrared sensors are vastly employed in industrial, commercial and general applications due to their simplicity and low price. Beam sensors are common type of these sensors which can detect objects when they cross its beam. Sequence of sensors which are crossed in a time order is called sensor word. Consider an object, produced sensor word shows the order which it has crossed the beams. If we have more than one object then sensor word is combination of all sensor words produced by all object. We need to separate each sensor word. In this research, sensor word is developed to Fixed-Charge Minimum Cost Maximum Flow Network type.In this case, the consequent... 

Natural boron consists of two stable isotopes, mass 10 (19.3%) and mass 11 (80.7%). 10B isotope has a large thermal neutron capture cross-section and it therefore, used widely in such aspects as modern industry, military equipment, medical science and so on. specially the demand of atomic energy industry for the boron isotope is increased severely. So the separation of 10B from natural boron has received very wide attention at present. There are many kinds of methods on the boron isotopes separation, such as chemical exchange reaction and distillation in boron trifluoride method, ion exchange in boric acid solution method, counter current recycle membrane cascades in boron trifluoride... 

Cardiovascular (CV) system is very similar to a wireless communication system in which a common input signal from the heart is fed into different arterial channels throughout different body parts. By putting multiple sensors on different peripheral body sites effects of this circulation from the heart can be recorded and be used as inputs for different multi channel blind system identification (BSI) methods for estimation of arterial channel dynamics. This Thesis is defined in order to investigate different BSI methods capability in CV characterization. To achieve this goal photoplethysmogram signals has been used as primary sensory recorded effect of heart function at three different... 

Zeolite membranes are of interest due to their special properties; thermal and mechanical resistances and non-plasticization property in gas separations. Therefore, separation of H2S from natural gas by these membranes is the main goal of this thesis which is not investigated in the world. After some theoretical investigations including diffusion mechanisms of gases in the zeolites and adsorption mechanism of H2S on the zeolites, pure silica CHA-type (Si-CHA) zeolite was selected. After successful synthesis of Si-CHA zeolite, adsorption isotherms of H2S, CO2, and CH4 on the Si-CHA zeolite were measured over pressure range of 0-190 kPa and temperatures of 25 °C, 50 °C, and 75 °C. Acid gases... 

Conversion of Methane molecule to valuable heavier hydrocarbon and hydrogen by using of short pulse lasers is investigated. The dynamical information of molecule such as orientation, dipole moment variations with binding length, and potential energy levels are initially produced by using Gaussian software. Based on this information the Schrödinger wave equation for this polyatomic molecule is numerically solved. Then by selecting the various laser parameters and installing of them in the Hamiltonian of the mentioned system, the dependence of hydrogen transition and separation probability on these parameters are investigated. In this work by radiating of the laser beam along the C2 symmetry... 

In this research incorporation of SAPO-34 zeolite filler into polycarbonate membrane was investigated for fabrication of mixed matrix membrane (MMM). The main purpose of addition of zeolite in polymer matrix is to enhance the separation properties of pure membrane by means of the selective pores of SAPO-34. SAPO-34 possesses pores with proper size for separation of CO2 from CH4 by molecular sieving mechanism. Pure polycarbonate membrane and PC/SAPO-34 MMM was prepared by solvent evaporation method using dichloromethane as solvent. Zeolite loading was varied between 5-30%wt. First of all, polycarbonate was characterized by DSC, FTIR and viscometer analysis in order to determine all the... 

The process of separating cells from a laboratory sample, is a crucial step in biotechnology and medical science. Cells separation is important for various reasons, including the identification and treatment of diseases, as an example, separation of Circulating Tumor Cells (CTCs) from patient blood sample. CTCs are cells that shed from a tumor and diffuse into blood vessels. These cells are the starters of metastasis, the process in which cancer spreads in body, and are main reason of deaths caused by cancer. Extremely low percentages of target cells in the blood, clarify the importance of highly accurate and sensitive separation. Currently, conventional separation methods are of macro-order... 

Structural system identification from vibration data is one of the most interesting research topics in the structural health monitoring area. Recently, realization and detection of the effects of damage when a structure is subjected to strong ground motion has become a great concern in earthquake and structural engineering communities. Seismic signal processing is one of the most reliable methods of detecting the structural damage during earthquakes. The structural responses during earthquakes are nonstationary with respect to both amplitude and frequency. The state-of-the-art time-frequency distributions when applied to vibration records were studied. Different methods of analysis for... 

At the beginning of the 20th century, Albert Einstein introduced the equations of general relativity, opening a new avenue for investigating various phenomena. One of the predictions of these equations, gravitational lensing, was observed by Eddington during his lifetime, confirming the theory's ability to describe nature. Gravitational lensing can be categorized into three types: strong lensing, weak lensing, and microlensing. The current focus of research is on observing the separation phenomenon in gravitational microlensing. The observation of gravitational microlensing provides valuable insights into the composition of celestial bodies in the universe. Calculating the mass of different... 

The recent breakthroughs in the lab-on-a-chip technology will not be directly used as clinical devices unless the specific applications are carefully tested and certified. As there is a growing trend towards microfluidic devices for biomedical research, an active microfluidic device was developed. Common microfabrication methods were used to develop a microchip to separate and concentrate exosome and particular cell based on the dielectrophoresis phenomenon. Unique capabilities of the dielectrophoresis phenomenon make it a powerful tool for micro particle manipulation in micro scale. In this research, geometry for the mentioned purpose is designed and optimized. Three-dimensional... 

Low frequency (LF) O2 plasma was used to modify the surface of polysulfone (PSF) gas separation membranes. The effect of treatment time and plasma power input on the membranes was also investigated. Pure CO2 and CH4 gas permeation measurements were performed before and after plasma treatment. The results showed the increase of permeability of the treated membranes due to surface ablation and surface polarization. However, the CO2/CH4 permselectivity of the treated membranes varied from 7.7 to 45.3 depending on the treatment conditions. Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy determined the introduction of oxygen containing polar groups on the surface... 

Epilepsy is a neurological disorder whose prevalence is estimated to be 1% of the world population. Electroencephalogram (EEG) is one of the best and convenient non-invasive tools used in diagnosis and analysis of this disease. Epileptic components extracted from EEG recordings are widely used in neuroscience in the diagnosis analysis like epilepsy source localization. However, epileptic components are often contaminated and covered with artifacts of physiological origin (baseline, EMG, ECG, EOG, etc.) or instrument noises (power supply, electrode, etc.). So, preprocessing and denoising is necessary for precise analysis of epilepsy EEG recording. Heretofore, several methods have been... 

The most popular system for quantification of the facial behaviors and expressions is the Facial Action Coding System (FACS). FACS provides a description of all possible and visually detectable facial variations in terms of 33 Action Units (AUs). The activation of each AU leads to a slight variation in the facial appearance, and any facial expression can be modeled by a single AU or a combination of AUs. Definition of AUs is such that they are sparse in multiple domains. The goal of this dissertation is utilizing these sparsity properties to develop an effective algorithm for automatic intensity estimation of AUs. One of the sparsity domains of AUs is the spatial domain that means the... 

A brass vortex tube (VT) with changeable parts is used to investigate the effect of nozzle intakes number and diameter, distance between cold end orifice and nozzle intakes, cold end orifice diameter, main tube length and diameter on inlet, cold and hot exit temperature difference, isentropic efficiency and Coefficient of Performance. A series of experiments conducted to investigate the inlet pressure and cold fraction effect on VT performance and an optimum amount for this parameter is found. The separation performances of a VT for a hydrocarbon mixture is also investigated. Effects of nozzle intakes number and cold fraction on the gas species separation at specific inlet pressure in a VT... 

Blind separation of mixed graph signals is one of the new topics in the field of graph signal processing. However, similar to the most proposed methods for separating traditional signals, it is assumed that the number of observed signals is equal to or greater than the number of sources. In this thesis, we show that a signal can be uniquely decomposed into the summation of a set of smooth graph signals, up to the indeterminacy of their DC values. From the blind source separation point of view, this is like the separation of a set of graph signals from a single mixture, contrary to traditional blind source separation in which at least two observed mixtures are required. Moreover, we... 

In Lithium ion batteries, the separator is membrane that placed between the cathode and the anode is one of critical components. Its primary function is to effectively transport ionic charge carriers between two electrodes as an efficient ionic conductor as well as to prevent the electric contact between them as a good electric insulator. The separator does not involve directly in any cell reactions, but its structure and properties play an important role in determining the battery performance. Commercially available polyolefin separators low cost, good electric resistance, high electrochemical stability, and effectively prevent thermal runaway caused by the electrical short-circuits or...