Nanoscale flow

Zeta potential plays an important role in micro-and nanoscale flow and transport processes. More... 

Photometer is important for identifying the materials in micro- and nanoscale flow, especially when the channel size is small and the flow speed is high. Although photometer itself does not have spatial resolution, the development of nanofluidics for single-molecule detection should be desirable to develop new experimental methods and applications for single-molecule-based applications. 

Classic flow rate measurement tools are mass flowmeter, electromagnetic flowmeter, rotameter, and turbine flowmeter, their measurement ranges being normally larger than 10 m /s (0.1 mL/s). But in microscale flows, the range of flow rate is usually 10-10 m /s, in other words 10 pL/s— 1 iiL/s. In nanoscale flows, the flow rate is from 10 to lOm /s (IpL/s IfL/s). So the measurement and calibration methods will be different for micro- or nanoscale flows, compared to classic macroscale flows. 

Surface conductance is important in micro- and nanoscale flow and transport processes, especially when the channel size is small and the ionic concentration of the bulk solutions (bulk liquid conductivity) is low. More experimental data of surface conductivity are needed for various liquid-microchannel systems. With the rapid development of nanofluidics, it is highly desirable to develop new theoretical models, experimental methods, and the experimental data for surface conductance of nanochannels. 

The application of molecular tagging-based visualization to nanoscale flows is an exciting research direction. The molecular dimensions of these probes make them well suited to these... 

However, the length and time scales that molecular-based simulations can probe are still very limited (tens of nanosecond and a few nanometers), due to computer memory and CPU power limitations. On the other hand, nanoscale flows are often a part of larger scale devices that could contain both nanochannels and microfluidic domains. The dynamics of these systems depends on the intimate connection of different scales from nanoscale to microscale and beyond. MD simulation cannot simulate the whole systems due to its prohibitive computational cost, whereas continuum Navier-Stokes simulation cannot elucidate the details in the small scales. These limitations and the practical needs arising from the study of multiscale problems have motivated research on multiscale (or hybrid) simulation techniques that bridge a wider range of time and length scales with the minimum loss of information. A hybrid molecular-continuum scheme can make such multiscale computation feasible. A molecular-based method, such as MD for liquid or DSMC for gas, is used to describe the molecular details within the desired, localized subdomain of the large system. A continuum method, such as finite element or finite volume based Navier-Stokes/Stokes simulation, is used to describe the continuum flow in the remainder of the system Such hybrid method can be applied to solve the multiscale phenomena in gas, liquid, or solid. 

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