Microdrop Manipulation and Mixing Using Dynamic Ferrofluid Cage Array

2006 ◽  
Author(s):  
Woo-Bin Song ◽  
Zhenwen Ding ◽  
Chulwoo Son ◽  
Babak Ziaie
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Water Droplet ◽  
Dynamic Change ◽  
Simple Method ◽  
Mixing Effect ◽  
Array Pattern ◽  
Simulation Results ◽  
The Magnetic Field

In this paper, we present a simple method to manipulate free microdroplets using ferrofluid dynamics. First, we use two strip magnets (20 Gauss) to generate a ferrofluid cage-array pattern. Then, a magnetic stirrer (200 Gauss) is placed and rotated underneath them to induce a dynamic change in the pattern. The generated ferrofluid pattern and its dynamics are compared with the simulation results of the magnetic field distribution under various static/dynamic configurations using finite element method (FEM). The mixing effect in individual cells is investigated using silica beads (0.2 μm in size) and a water droplet (40 microliter in volume) first. In order to demonstrate free droplet mixing, two colored water microdroplets (10 microliter in volume) are placed in two separate wells and are driven to move and mix without sample evaporation.

scholarly journals Static force characteristics of electromagnetic actuators for Braille screen

2011 ◽  
Vol 24 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Ivan Yatchev ◽  
Krastio Hinov ◽  
Iosko Balabozov ◽  
Kristina Krasteva
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Permanent Magnet ◽  
Static Force ◽  
The Finite Element Method ◽  
Electromagnetic Actuators ◽  
Minimum Force ◽  
The Magnetic Field ◽  
Force Characteristics

Several constructions of electromagnetic actuators with moving permanent magnet for Braille screen are studied. All they are formed from a basic one that consists of two coils, core and moving permanent magnet. The finite element method is used for modeling of the magnetic field and for obtaining the electromagnetic force acting on the mover. The static force-stroke characteristics are obtained for four different constructions of the actuator. The constructions with ferromagnetic disc between the coils ensure greater force than the ones without disc and can reach the required minimum force.

The Comparison of Magnetic Leakage of Different Teeth Structures in Magnetic Fluid Seal

2011 ◽  
Vol 197-198 ◽  
pp. 314-317 ◽  
Author(s):  
Fei Fei Xing ◽  
De Cai Li ◽  
Wen Ming Yang ◽  
Xiao Long Yang
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Model ◽  
Field Distribution ◽  
Magnetic Fluid ◽  
Magnetic Field Distribution ◽  
Two Sides ◽  
The Magnetic Field ◽  
Sealing Gap

Based on the theoretical model, magnetic field distribution of rectangular teeth, two-sides dilated shape and one-side dilated shape teeth structure with common other conditions were calculated using finite element method when the sealing gap was 0.1mm and 0.12mm. The comparison of their results with the same sealing gap showed that rectangular teeth structure had the highest magnetic leakage. Moreover, the magnetic field distribution of sealing structures with rectangular stages on both the shaft and pole pieces under the same design and sealing gap were also calculated using the same method, whose result was compared with rectangular stages on pole pieces only. The comparison showed that the former did not have higher pressure capability obviously but led to higher magnetic leakage.

scholarly journals New Constitutive Matrix in the 3D Cell Method to Obtain a Lorentz Electric Field in a Magnetic Brake

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3185 ◽  
Author(s):  
José Monzón-Verona ◽  
Pablo González-Domínguez ◽  
Santiago García-Alonso
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Computer Applications ◽  
The Finite Element Method ◽  
Cell Method ◽  
Hall Sensors ◽  
Constitutive Matrix ◽  
The Magnetic Field ◽  
Made In

In this work, we have obtained a new constitutive matrix to calculate the induced Lorentz electric current of in a conductive disk in movement within a magnetic field using the cell method in 3D. This disk and a permanent magnet act as a magnetic brake. The results obtained are compared with those obtained with the finite element method (FEM) using the computer applications Getdp and femm. The error observed is less than 0.1173%. Likewise, a second verification has been made in the laboratory using Hall sensors to measure the magnetic field in the proximity of the magnetic brake.

Relationships Between the Proportional Law and the Charts Used in ASME VIII-1 and EN13445-3 for Designing Shells and Tubes Under External Pressure

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Huan Sheng Lai ◽  
Kang Lin Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
External Pressure ◽  
Tension Stress ◽  
Stress Strain ◽  
Simple Method ◽  
Calculation Process ◽  
Simulation Results ◽  
Critical Buckling Pressure ◽  
Element Method

Shells and tubes usually fail in the form of buckling under external pressure. Charts are used in the design of shells and tubes in the standards of ASME VIII-1 and EN13445-3 and these simplify the calculation process, while the proportional law is a more effective and simple method. In this paper, the relationships between the proportional law and the charts used in the standards were researched; finite element method (FEM) was used to compare the accuracies of the proportional law and the charts. It was theoretically proved that the proportional law and the charts were using essentially the same method to calculate the critical buckling pressure; they were different forms of the same dimensionless tension stress–strain curves. The simulation results showed that the proportional law and the charts had effectively equal accuracies in calculated critical buckling pressures. Therefore, the proportional law can be a candidate method included in the standards for the design of shells and tubes under external pressure.

Modeling and Design Optimization of Contactless Sliding Transformer System for Ropeless Elevators

2013 ◽  
Vol 416-417 ◽  
pp. 264-269
Author(s):  
Pei Long Wang ◽  
Xiao Zhuo Xu ◽  
Bao Yu Du ◽  
Hai Chao Feng ◽  
Xu Dong Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Finite Element ◽  
Permanent Magnet ◽  
Power Transmission ◽  
Electrical Power ◽  
Coupling Coefficients ◽  
The Finite Element Method ◽  
The Magnetic Field ◽  
Load Conditions

In this paper, two novel topological structures of sliding transformer with ferromagnetic core applied in the Contactless Electrical Power Transmission (CEPT) system used for the ropeless elevator driven by moving-coil type Permanent Magnet Synchronous Linear Motor (PMLSM) have been proposed, and the magnetic field distribution is calculated and analyzed by the finite element method (FEM). According to the analysis results of the traditional E-E topology sliding transformer, much higher coupling coefficients of sliding transformers with proposed topologies have been obtained. Then, based on the magnetic distribution and the circuit model of system, the compensation capacitances have been calculated considering supply frequency and load conditions. Finally, the load characteristic of the system with compensation is also obtained by FEM.

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