Sharif Digital Repository

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 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... 

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... 

This study investigates the dynamics of a two-mass oscillator travelling on a viscoelastic rectangular plate under both accelerating/decelerating and uniform motions, while accounting for surface roughness and various reattachment scenarios. Despite its practical significance, this topic has received limited attention in scholarly literature. The Current article studies how key parameters—including the oscillator’s initial velocity, acceleration, foundation/oscillator damping and stiffness, as well as impact type (elastic, plastic, and elastoplastic)—affect the system’s dynamic response. It also examines, via illustrative examples, the oscillator’s motion along paths parallel and diagonal to... 

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... 

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... 

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... 

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 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... 

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....