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... 

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... 

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... 

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... 

Microfluidics, employing fluids in structures with micrometer dimensions, is an emerging technology that has brought great opportunities to develop various devices including lab-on-a-chip systems. Lab-on-a-chip systems have the advantages of integrating several stages of different analytical methods, application in diverse fields, consumption of small volumes of samples, and portability. One of the crucial applications of lab-on-a-chip devices is sorting cells and biological particles, done by different methods. In separator devices, high separation efficiency and repeatability are critical. When a neutral particle is polarized in a non-uniform electric field, the dielectrophoresis force... 

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... 

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... 

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... 

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... 

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... 

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... 

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 ... 

Triclosan is widely used as an antibacterial agent in personal health care products, especially in recent years with the spread of the Coronavirus. This substance is one of the emerging contaminants, and due to its stable and toxic nature, this material cannot be destroyed in the process of biological wastewater treatment. In this research, a new bacterial strain was isolated and purified from industrial wastewater for the biological removal of triclosan. Based on 16S rRNA sequencing, it was found that the isolated strain belongs to the Enterobacter cloacae family and can grow in high concentrations of triclosan. It was observed that naphthalene dioxygenase and laccase enzymes are active... 

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,... 

% 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... 

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... 

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... 

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...