مهدی مقیمی زند
دانشکده مهندسی مکانیک، پردیس دانشکده های فنی، دانشگاه تهران
[ 1 ] - طراحی و شبیه‌سازی یک سیستم میکروسیالی نوین برای انتخاب و پالایش اسپرم پویا با استفاده از الکتروفرسیس
از آن‌جاکه پویابودن یک پارامتر مهم در تعیین کیفیت اسپرم است، عملیاتی که بتواند اسپرم‌های پویا را به بهترین شکل و کمترین خطر جدا کند، برای درمان ناباروری مطلوب است. در میان راه‌های مختلف برای جداسازی و سرندکردن اسپرم‌های پویاتر، روش‌هایی که از میکروکانال استفاده می‌کنند، از نظر سادگی و کاربرپسندی و سازگاری با طبیعت از دیگر روش‌ها پیش افتاده‌تر هستند. سئو و همکاران (۲۰۰۷) سیستمی را طراحی کرده‌اند...
[ 2 ] - Dynamics of nonlinear rectangular plates subjected to an orbiting mass based on shear deformation plate theory
In this paper, transverse and longitudinal vibration of nonlinear plate under exciting of orbiting mass is considered based on first-order shear deformation theory. The nonlinear governing equation of motion are discretized by the finite element method in combination with Newmark’s time integration scheme under von Karman strain-displacement assumptions. For validation of method and formulation...
[ 3 ] - Dielectrophoretic effect of nonuniform electric fields on the protoplast cell
In recent years, dielectrophoresis based microfluidics systems have been used to manipulate colloids, inert particles, and biological microparticles, such as red blood cells, white blood cells, platelets, cancer cells, bacteria, yeast, microorganisms, proteins, DNA, etc. In the current study the governing electric potential equations have been solved in the presence of cell for the purpose of ...
[ 4 ] - Dynamic and Static Pull-in instability of electrostatically actuated nano/micro membranes under the effects of Casimir force and squeezed film damping
In the current study, the effects of Casimir force and squeeze film damping on pull-in instability and dynamic behavior of electrostatically actuated nano and micro electromechanical systems are investigated separately. Linear elastic membrane theory is used to model the static and dynamic behavior of the system for strip, annular and disk geometries. Squeeze film damping is modeled using nonli...
[ 5 ] - Studying piezoelastic and piezomagnetoelastic configurations for different excitation frequencies in MEMS energy harvesters
Typically two configurations are used for energy harvesting with different advantages: piezoelastic and piezomagnetoelastic. Best performance of the piezoelastic configuration is when the excitation frequency is close to the resonance frequency. If the input frequency slightly deviates from the natural frequency, the generated power is severely decreased. To tackle the problem, the piezomagneto...
[ 6 ] - A Computational study on the effect of different design parameters on the accuracy of biopsy procedure
Needle insertion is a minimally invasive technique in diagnosing and treating tumors. However, to perform a surgery accurately, the tissue should have minimum amount of displacement during needle insertion so that it reaches the target tissue. Therefore, the tissue membrane has to move less to decrease rupturing under the membrane. In this study, the effect of different design parameters on dis...
[ 7 ] - Thread Pitch Variant in Orthodontic Mini-screws: A 3-D Finite Element Analysis
Orthodontic miniscrews are widely used as temporary anchorage devices to facilitate orthodontic movements. Miniscrew loosening is a common problem, which usually occurs during the first two weeks of treatment. Macrodesign can affect the stability of a miniscrew by changing its diameter, length, thread pitch, thread shape, tapering angle and so on. In this study, a 3-D finite element analysis wa...
[ 8 ] - Pull-In Instability and Vibrations of a Beam Micro-Gyroscope
Gyroscopes are used as rotation rate sensors. Conventional gyroscopes are heavy and bulky, which creates important problems regarding their usage in different applications. Micro-gyroscopes have solved these problems due to their small size. The beam micro-gyroscope is one of the popular types of inertial sensors. Their small dimensions and low energy consumption are key reasons for their popul...
[ 9 ] - Effect of Stress-Fiber Inclusion on the Local Stiffness of Cell Cytoskeleton Probed by AFM Indentation: Insights from a Discrete Network Model
In this paper, we analyze the effect of stress-fiber inclusion on the stiffness of an actin random network. To do this, use a discrete random network model to analyze the elastic response of this system in terms of apparent Young’s modulus. First, we showed that for a flat-ended cylindrical AFM indenter the total indentation force has a linear relation with the indentation depth and the indente...