Thermal control of ionic transport and fluid flow in nanofluidic channels

Nanoscale ◽  
2015 ◽  
Vol 7 (44) ◽  
pp. 18799-18804 ◽  
Author(s):  
Mojtaba Taghipoor ◽  
Arnaud Bertsch ◽  
Philippe Renaud
Keyword(s):  
Fluid Flow ◽  
Ionic Transport ◽  
Thermal Control ◽  
Nanofluidic Channels ◽  
Fast Mechanism

A thermal gate is an effective and fast mechanism for modulating the ionic transport in nanofluidic channels.

Effect of Time Dependent Excitation Signals on Gating in Nanofluidic Channels

2015 ◽  
Author(s):  
C. Boone ◽  
M. Fuest ◽  
K. Wellmerling ◽  
S. Prakash
Keyword(s):  
Electric Field ◽  
Ionic Transport ◽  
Local Variation ◽  
Time Dependent ◽  
Local Perturbation ◽  
Gate Electrode ◽  
Nanofluidic Channels ◽  
Field Effect Devices ◽  
Dc Excitation ◽  
Dependent Signal

Nanofluidic field effect devices feature a gate electrode embedded in the nanochannel wall. The gate electrode creates local variation in the electric field allowing active, tunable control of ionic transport. Tunable control over ionic transport through nanofluidic networks is essential for applications including artificial ion channels, ion pumps, ion separation, and biosensing. Using DC excitation at the gate, experiments have demonstrated multiple current states in the nanochannel, including the ability to switch off the measured current; however, experimental evaluation of transient signals at the gate electrode has not been explored. Modeling results have shown ion transport at the nanoscale has known time scales for diffusion, electromigration, and convection. This supports the evidence detailed here that use of a time-dependent signal to create local perturbation in the electric field can be used for systematic manipulation of ionic transport in nanochannels. In this report, sinusoidal waveforms of various frequencies were compared against DC excitation on the gate electrode. The ionic transport was quantified by measuring the current through the nanochannels as a function of applied axial and gate potentials. It was found that time varying signals have a higher degree of modulation than a VRMS matched DC signal.

Fluid Flow and Entropy Generation Characteristics Analysis of the Channel Geometry in X-Shaped Micro-Channels

2011 ◽  
Author(s):  
Shu-Min Tu ◽  
Shuichi Torii ◽  
Yang-Cheng Shih
Keyword(s):  
Fluid Flow ◽  
Entropy Generation ◽  
Thermal Control ◽  
Working Fluid ◽  
Main Concern ◽  
Channel Geometry ◽  
Micro Channels ◽  
Wide Range ◽  
Characteristics Analysis ◽  
Acrylic Fabric

The micro-channels and micro-devices have been widely used in mechanical engineering applications. A number of investigations have been conducted to better design the fluid flow and heat transfer in micro-channel, particularly as it pertains to applications involving the thermal control of electronic devices. The analysis of entropy generation mechanism is very important to optimize the second-law performance of these energy conversion devices in micro-scale. The main concern of this paper is to investigate the channel geometry effect on the mixing performances in the X-shaped micro-channels. Seven different tested channels consisting of shrunk-channel, normal-channel and magnified-channel, made of acrylic fabric with the width ranging from 0.7 to 1.3 mm, are considered. As the working fluid, water, is injected to microchannel at different mass flow rate, over a wide range of flow condition, 0.52 < Re < 718, have been discussed. Numerical simulation of the entropy generation, temperature gradient, velocity vector, and pressure drop has deliberated with experiment. Through the evaluations of the overall entropy generation in the whole flow domain, the results show that; as the Reynolds number below 136.68, magnified-channels have the lower entropy generation and best mixture of performance; above 136.68, in the smallest the channel geometry, the transition form early from laminar flow, the unsteady flow is an advantage for mixing in the limited mixing area, therefore, they generated the best mixing performance. It is clear that the channel geometry plays an important role on the mixing performances in the X-shaped micro-channels.

Scanning-probe microscope analysis of optical thin films: A new analytical tool in a manufacturing environment

1994 ◽  
Vol 52 ◽  
pp. 1068-1069
Author(s):  
S. P. Sapers ◽  
R. Clark ◽  
P. Somerville
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Thermal Control ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
List Type ◽  
Manufacturing Environment ◽  
Physical Measurements ◽  
Probe Microscope

OCLI is a leading manufacturer of thin films for optical and thermal control applications. The determination of thin film and substrate topography can be a powerful way to obtain information for deposition process design and control, and about the final thin film device properties. At OCLI we use a scanning probe microscope (SPM) in the analytical lab to obtain qualitative and quantitative data about thin film and substrate surfaces for applications in production and research and development. This manufacturing environment requires a rapid response, and a large degree of flexibility, which poses special challenges for this emerging technology. The types of information the SPM provides can be broken into three categories:(1)Imaging of surface topography for visualization purposes, especially for samples that are not SEM compatible due to size or material constraints;(2)Examination of sample surface features to make physical measurements such as surface roughness, lateral feature spacing, grain size, and surface area;(3)Determination of physical properties such as surface compliance, i.e. “hardness”, surface frictional forces, surface electrical properties.

Short stroke linear motor controls fluid flow

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-805-Pr2-808
Author(s):  
A. Basak
Keyword(s):  
Fluid Flow ◽  
Linear Motor ◽  
Motor Controls
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