Electrokinetic Flow Dynamics of Weakly Aggregated λDNA Confined in Nanochannels

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Satoshi Uehara ◽  
Hirofumi Shintaku ◽  
Satoyuki Kawano
Keyword(s):  
Theoretical Model ◽  
Electric Field ◽  
High Speed ◽  
Terminal Velocity ◽  
Flow Dynamics ◽  
Radius Of Gyration ◽  
Channel Height ◽  
Next Generation ◽  
Electrokinetic Flow ◽  
Design Data

Flow dynamics in nano-scaled structures such as nanochannels and nanopores have recently become important in developing next-generation high-speed DNA sequencers. In the present paper, we report the electrokinetic flow dynamics of λDNA confined in nanochannels having heights that are smaller than the molecular radius of gyration. Nanochannels of varying heights of from 330 to 650 nm were used in the experiments in order to systematically investigate the effect of confinement. Weakly aggregated λDNA flowed in a direction opposite to an applied electric field as a result of the competition of electrophoresis and electroosmotic flows. The terminal velocity of λDNA was proportional to the strength of the electric field, and the mobility was found to decrease with the channel height. A simple theoretical model explaining the decrease in the mobility was developed taking into account the shear stress due to small clearances between λDNA and the walls of nanochannels. The validity of the model was confirmed by reasonable agreement between the theoretical and experimental results. The theoretical model and the transport properties under confinement provide basic design data for the development of next-generation DNA sequencers.

Investigation of the Effect of Geometric Parameters on EWOD Actuation in Rectangular Microchannels

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Sajad Pooyan ◽  
Mohammad Passandideh-Fard
Keyword(s):  
Theoretical Model ◽  
High Speed ◽  
Channel Width ◽  
Circuit Board ◽  
Design Parameters ◽  
Channel Height ◽  
Liquid Slug ◽  
Electrowetting On Dielectric ◽  
Transport Velocity ◽  
The Mean

Efficient actuation of liquid slugs in microfluidic circuits is a matter of interest in droplet-based microfluidic (DMF) applications. In this paper, the electrowetting on dielectric (EWOD) actuation of a liquid slug fully confined in a microchannel is studied. A set of experiments are conducted in which the mean transport velocity of a liquid slug enclosed in a microchannel of rectangular cross section and actuated by EWOD method is measured. A printed circuit board-based (PCB-based) microfluidic chip is used as the platform, and the transport velocity of the slug is measured by processing the images recorded by a high-speed camera while the slug moves in the channel. To investigate the effect of microchannel geometry on the mean transport velocity of the slugs, different channel heights and widths (ranging between 250−440μm and 1–2 mm, respectively) as well as different liquid volumes (ranging between 2.94and5.15μL) are tested and slug velocities up to 14.9 mm/s are achieved. A theoretical model is also developed to analyze the effect of involved parameters on the transport velocity. The results show that, within the range of design parameters considered in this study, for a constant slug volume and channel width, increasing the channel height enhances the velocity. Moreover, keeping the slug volume and channel height fixed, the transport velocity is increased by enlarging the channel width. An inverse proportionality between the slug length and velocity is also observed. These results are also shown to agree with the theoretical model developed.

Thermo-stress coupling field of friction lining during high-speed slide of wire rope in a mine friction-drive hoist

2011 ◽  
Vol 226 (9) ◽  
pp. 2154-2167 ◽  
Author(s):  
Yu-xing Peng ◽  
Zhen-cai Zhu ◽  
Min-ming Tong ◽  
Guo-an Chen ◽  
Yan-hai Cheng ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Contact Zone ◽  
Constitutive Relation ◽  
High Speed ◽  
Thermomechanical Properties ◽  
Element Analysis ◽  
Coupling Field ◽  
Zone Ii ◽  
Coefficient Of Linear Expansion ◽  
Friction Lining

In order to seek the intrinsic reason for the serious high-speed slide accident in a mine hoist, the thermo-stress coupling field of friction lining was studied during the high-speed slide. First, the helical contact characteristics were analysed. Subsequently, the thermomechanical properties and the dynamic coefficient of linear expansion were studied, and the thermomechanical constitutive relation was obtained. Then, the theoretical model of thermo-stress was established with the consideration of the helical contact characteristics and the thermomechanical constitutive relation. Also, the numerical simulation was performed by the finite element analysis. Finally, the experiment was carried out on a friction tester. It is found that the temperature is the highest at the contact zone II and the friction heat focuses on the contact surface layer. The variation frequency of the stress is 6.98 Hz at 0.5 m/s. Besides, the catastrophe for the strain and coefficient of friction occurs at 3 m/s. The thermo-stress concentration occurs at contact zone II. The experiment results agree with the simulation ones, which validates the theoretical model of thermo-stress.

scholarly journals Evaluation of 4-alkoxy-4′-nitrobiphenyl liquid crystals for use in next generation scattering LCDs

RSC Advances ◽  
2017 ◽  
Vol 7 (64) ◽  
pp. 40480-40485 ◽  
Author(s):  
Richard J. Mandle ◽  
Stephen J. Cowling ◽  
John W. Goodby
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Applied Electric Field ◽  
Field Studies ◽  
Next Generation ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

A combination of microscopy, X-ray scattering, calorimetry and applied electric field studies demonstrates the 4-alkoxy-4′-nitrobiphenyls are potentially of use for next generation, backlight free scattering mode LCD devices.

Design Concepts for the Next Generation of High-Speed Diesel-Electric Locomotives

2014 ◽  
Author(s):  
John Tunna ◽  
Jingjun Zhang ◽  
Adrian Gorski
Keyword(s):  
High Speed ◽  
Next Generation ◽  
Design Concepts ◽  
Passenger Rail ◽  
High Speed Diesel ◽  
Unsprung Mass

The Passenger Rail Investment and Improvement Act (PRIIA) Section 305 Next Generation Equipment Committee’s specification for diesel-electric locomotives has several challenging requirements. Among these is limiting P2 Force to 82,000 pound force (lbf) at 125 miles per hour (mph). To achieve this, the locomotive designer would have to balance unsprung mass and axle load. A design envelope exists within which that balance can be achieved. Advanced designs of traction and braking systems are required, and attention has to be paid to minimizing the overall mass of the locomotive.

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