Sharif Digital Repository

Xylene isomers have similar boiling points and, therefore, their separation by conventional distillation is not practical. The industrial separation of these isomers is generally performed by adsorption or crystallization processes, which are very energy consuming. In this work, the various methods of the separation of these isomers have been reviewed and the equilibrium adsorption of these components in liquid phase using two commercial types of zeolite including Z-700 and Na-BETA as adsorbent at 15, 25, and 35 oC and an initial concentration range of up to 50 wt% as well as in single and binary solutions was investigated. It was found that Z-700 adsorbent has no selectivity for the binary... 

Molecularly imprinted polymers (MIPs) with synthetic recognition sites are capable of detecting and separating chemical species in complex environments. These characteristics are of increasing interest for bioanalytical applications. The chief advantages of MIPs are mechanical and chemical stability, low cost, and ease of preparation. Recently, imprinting technology has been used for fabrication polymer thin films with recognition sites of proteins, plant viruses, and yeasts. Also few investigations applied lithography for synthesis of cell imprinted polymers targeting cell detection and observation of cell morphology.
For the first time, we demonstrate surface imprinting for the... 

Supported Ionic Liquid Membranes (SILMs) are fabricated by saturating the pores of a porous support with ionic liquids. To assess the performance of SILMS, it is necessary to obtain data about the properties of ionic liquids such as diffusivity, solubility, and etc. To accomplish this task, in this project the permeability and diffusivity of CO2 and CH4 through three immidazolium-based ionic liquids: [bmim][PF6], [hmim][Tf2N], and "1-methyl-3-(3- tri methoxi silil propyl) imidazolium bis (tri fluoro methyl solphonyl)" , in the temperature range between 27-45 ℃ and pressures within 10-50 kPa, are measured. It is shown in data validation section that the results of this study are in good... 

In today's complex engineering systems, any increase in efficiency naturally comes with concerns about accepted level of safety. As demand for aerial transportation is increasing, more researches are conducted to increase the capacity of current controlled airspaces; as the limited capacity of the so called "en-route" corridors appears to be the main concern in the industry. Meanwhile, a solution is expected to be in more efficient exploitation of the current airspace capacities via optimizing the standards related to maintaining Separation Minima (SM) among flying aircrafts. Current standards assume an aircraft to be at the center of a circle with a radius equal to 5 nm. In this work,... 

The main purposes of this project are simulation, design, and fabrication of a microfluidic system based on dielectrophoresis (DEP) exploiting AC voltages for separation of microparticles. Generally, this project can be divided into two parts. First, the engineering section including design and fabrication of microchip, and second biological samples preparation for investigating the system performance. The main advantages of proposed system are eliminating joule heating, a significant problem in insulating based dielectrophoresis systems, overcoming problems related to metal contamination in biological samples, the main problem of conventional dielectrophoresis platforms, and removing... 

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... 

Nowadays, separation and filtration of particles has many industrial applications in biology and medicine. In this thesis, passive microfluidics are designed and simulated which are able to separate and filter particles. Although particles aer generally expected to follow laminar flow streamlines in the absence of external forces, inertial forxes van cause particles to migrate across mictochannels in an accurate and predictable manner. The effect of these forces is invedtigated, and by using previous research, a model is developed to predict these forces. First design is a microchannel with Archimedean spiral which utilizes both inertial forces and Dean flow to separate particles in the... 

In this study, with respect to previous projects, we focused on size reduction of hollow and endohedral fullerenes research reactors. For this reason, we set up two reactors having 1/2 and 3 liters volumes and then such parameters as pressure, reactor temperature, arc duration time, arc time interval and the working electrical current through the electrodes circuit, in both reactors were optimized. The reactors, 3- and 1/2-liter reactors were of types of horizontal and vertical, respectively. In this project spatial angle between two electrodes were also found as effective variable on fullerenes yield in the 3-liters arc reactor for the first time. We found that upon correction of the... 

Waste of iron ore concentrate production plant of Chadormalu contains apatite mineral. The content of rare earths elements (REEs) in apatite concentrate of Chadormalu is about one percent. However, considering apatite deposite and production rate, extraction of REEs from apatite is one of valuable source for production of REEs. Lanthanum, cerium and neodymium which have most application amonge other REEs and have the highest frequency in the apatite. Due to their similar physical and chemical properties, it is difficult to separate individual rare earths from each other and the separation process are too complicated. In this study, in order to extract REEs from apatite, it was leached by... 

A new microfluidic device is introduced for sorting the particles based on the hydrodynamic resistance induced in a microchannel which is not needed for additional detection or sorting modules. Hydrodynamic resistance affects physical properties, such as size and deformability of the particle. This device could apply application in cell sorting for remedies, diagnostics, and industrial applications. The device design is performed using an equivalent resistance model, and also numerical simulations are performed. For validation of the results, they are compared with experimental results. Moreover, we will discuss threshold particle size and will introduce a way to approximate it to ... 

Here, the properties of separability of linkages are studied. In general, a linkage is a simple polygonal chain embedded in 3-space with disjoint, straight-line edges, which are fixed-length bars. The internal vertices are called joints. If the two end points are connected then the linkage is a closed linkage, otherwise it is an open linkage. By imposing restrictions on the way the bars in joints can move, three kinds of linkages as rigid, revolute and flexible can be introduced. A motion in a linkage is the motion of its vertices that preserves the length of the bars, and adheres the restrictions on joints. A collection of linkages are said to be separatable if for any distance d, there is... 

Clogging of the pores of the porous medium occurs in different processes such as geothermal injection pumps, hydrocarbon wells, and underground water extraction wells. We need a model that can simulate these blockages in order to predict how fundamental variables of the porous medium change under different flow regimes and different particle sizes in the fluid (for example, the relationship between porosity and permeability changes). The aim is to simulate clogging in a porous medium using a pore network model. Simulations should model pore clogging and show how the permeability of the sample changes due to pore clogging. In the pore network, there are often thousands (or millions) of pores... 

Cancer is an abnormal growth of cells which is one of the major cause of worldwide’s mortality. Circulating Tumor Cells (CTCs) are rare cancer cells released from the primary or metastatic tumors and transported though the peripheral circulatory system and spreads in body and seize healthy organs. Early detection of CTCs can help in overtaking the cancer, hence isolation of CTCs is an essential step for many therapeutics. In spite of its clinical potential, the isolation and detection of CTCs has been a challenging task due to its rare presence amongst other blood cells (as low as 1–10 CTCs per billions of blood cells), similarity to white blood cell in size and also variability in terms of... 

In this study, investigated the simulation flow over a double-delta wing. The flow field was simulated by three dimension grid and RANS flow equation by K-ω-SST model. In order to investigate effect of AOA and leading edge flap simulated variable AOA and leading edge flap angle. The results shows created two vortex in inside and outside the wing. The vortex burst at high AOA and the Lift decrease after vortex bursting. The using leading edge flap effect on the vortex power and postpone vortex bursting and increasing wing lift coefficient in the high AOA. Also the leading edge flap effect on the pitch moment coefficient and change the pitch moment coefficient curve slope. The other effects of... 

According to statistics in 2012, around 14 million people worldwide have cancer, and 8 million have died that year, according to estimates, this number will increase to 21 millions new cancer case and 13 million mortality in 2030. Despite years of research on cancer, many questions about the mechanism of the spread of cancer in the body remain unanswered so far. The proposed models identify that the cells isolated from the primary tumor and transmit them to the circulatory system in the form of circulating tumor cells (CTCs) or in the form of clusters as responsible for the incidence of cancer. This process is called metastasis. Recent studies have reported the high potential of metastasis... 

Due to population growth, the demand for water supply has increased. This need has drawn attention to the use of consumed and treatable water resources. Organic pollutants are a key source of water pollution. On the other hand, petrochemical oil pollution and frequent oil accidents during oil production or maritime transport have become one of the environmental problems.There are different methods for water and oil separation and water purification that in the present project, selective separation can be achieved by using hydrophobic materials and surface roughness and creating surfaces with two properties: superhydrophobic and ultra-oil friendly. This method is also very effective, cheap... 

In the dairy industry, for the processing of raw milk, including the isolation of living bacteria and microorganisms from milk to increase the shelf life and improve the taste of milk, or the isolation of casein and whey proteins from milk for pHarmaceutical and medical purposes, as well as the production of low-lactose or lactose-free milk for patients with Digestive problems, use membrane processes, especially ultrafiltration and microfiltration, and the main problem in these methods is the fouling of the polymer membranes used, which results in the loss of flux or the reduction of product quality and system efficiency. With the help of bulk modification and surface modification of the... 

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... 

Separation of particles and cells is one of the most important and practical methods in fields such as biomedicine, medicine and industry. In microfluidics There are various methods for particles and cells separation According to the source of them, they can be categorised as active and passive techniques. Active techniques rely on an external force field. The most important advantage of this method is controlling the force on the particles during the experiment. However, the flow speed is always limited because particles must be exposed to the outer force field for sufficient duration to achieve effective functionality. passive techniques depend entirely on the channel geometry or intrinsic... 

According to studies, cancer is the second leading cause of death in the world and millions of people die from this disease every year. Early diagnosis is one of the most important factors in controlling and treating the disease. The ability of circulating tumor cells to diagnose and monitor the disease has led many researchers to focus on studying and researching these cells in recent years. However, due to the fact that the concentration of this type of cells in the blood is very low, their isolation is associated with challenges. Various methods isolate CTCs based on physical, biological and other differences in characteristics. In this study, we investigate performance of a microfluidic...