Sharif Digital Repository

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... 

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... 

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... 

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,... 

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... 

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... 

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... 

% of human blood makes up of plasma, that this plasma is a rich source of proteins that can be used as biomarkers for a variety of clinical diseases and laboratory research, therefore, it is necessary that the plasma be separate by a high purity percentage. Using a centrifuge It is a common method used to separate plasma from blood, but because it requires large equipment and a large volume of blood, as well as stress caused by centrifugal force, increases the probability of damage to the biomarkers, so it has been tried today that Use methods that are easy to transport and require a small amount of blood. The idea of using the microfluidic device has been put forward for the purpose of... 

Today, microfluidic experiments have found wide applications in medical sciences, engineering, and chemistry. Because of their small size, microfluidic devices help us to be able to use very little amount of sample for the experiments and also easily control and observe the under-experiment fluid. One of the most important applications of these devices is the separation of cancer cells in blood for counting their number and DNA genetic studies. In the current project we have tried to do the separation of cancer cells from other cells by designing an inertia microchannel. For this purpose, in the first step a geometry for the channel is designed with analyzing the induced forces on the cells.... 

The increasing demand for energy forced to production of oil as one of the main sources of energy. Along with the increase in oil production, the proportion of water produced with oil is increasing relative to the oil produced. On the other hand, environmental restrictions for the discharge of industrial effluents into the environment are becoming more and more stringent every day. Before discharging the effluent into the environment, petroleum must be removed. The complexity of these issues demonstrates the need to develop new technologies and improve the efficiency of existing technologies. Gas flotation are among the technologies adopted in the field that have been used throughout the... 

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... 

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 ... 

From 1384 to 1395, the labor market in Iran has experienced a mysterious behavior in total number of employment, which we call it puzzle of jobless growth and growthless employment. By studying only the net changes in total number of employment, some important information neglected in explaining this phenomenon. To this end, it is common in labor economics to use dynamic labor market indicators such as job flows and labor flows. In this research, we first calculate labor flows from 1384 to 1395 and job flows from 1382 to 1392 by economic sector, firm size, job classification, occupational insurance coverage, gender and job type. Then the following question will be answered: Is the... 

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... 

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... 

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 live and dead cells 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 microelectrodes are... 

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... 

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...