Sharif Digital Repository

Dynamic analysis of deploying elastic arms of spacecrafts carrying tip mass has been presented. The research concentrates on the precise analytical simulation to reveal the phenomena which are usually eliminated in estimations. One of the most important factors which affect the dynamic response of such arms is rigid body dynamics of spacecraft. Considering this aspect of the problem the evolutionary analytical simulation has been developed through three steps. The first step focuses on the minute simulation of the arm deployment, in which a new mathematical approach called "elastic profile" has been developed which leads to semi-analytical solutions for the arm carrying tip mass.... 

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... 

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... 

Cell lysis, as the first procedure of cell pretreatment, is a process that breaks cell membranes open thereby facilitating access to intracellular substances, such as DNA, proteins, and other components for further analysis to diagnose and treat diseases at early stages. Currently, there are several methods for cell lysis at macroscales. However, the time-consuming and expensive procedures as well as the large scal of the system are the main disadvantages of the systems. Recently, microfluidic systems have attracted considerable attention due to advantages associated with automation, integration and miniaturization of biomedical test protocols. Centrifugal microfluidics (Lab-on-a-Disc) is a... 

Deoxyribonucleic acid (DNA) extraction, as one of the most important steps in modern molecular diagnostics, is the process by which DNA is separated from intracellular materials like proteins, membranes, and other materials contained in the cell. Microfluidic technology enables sophisticated, time-consuming and costly experiments with minimal use of raw materials, time and cost and acceptable accuracy. The predominant advantages of centrifugal microfluidic systems are utilizing centrifugal force to generate propulsion without the need for a pump, and eliminating the need for experts to run the system. Various fluidic operations such as valving, mixing, metering, heating, and sample...