Flow Management

In order to produce a robust flow for chromatography on a chip, and which is in the low nanoliter per minute range, several approaches are possible. Flow is either produced by pressure-driven devices (referred to as top-down systems) or by electroosmosis-driven devices (referred to as bottom-up systems). 

Conventional HPLC pumps, in the absence of robust nanopumps, are used with a split to create a nanoflow. Although robust flows can be obtained, the drawbacks are 

Electrochemical pumps create flow-through electrolysis of the mobile phase in a closed reservoir on the chip. This process leads to gas formation, which in turn can cause a hydrodynamic flow of up to SOnlmin.  

Laser-induced fluorescence (LIF) is particularly suited for detection on the micro chip. It is easy to focus the light bundle on the optical path of the system and it is little susceptible to background noise due to its specificity. In addition to this, combining LIF with sensitive photomultiplier tubes (PMT) makes it very sensitive. The LIF 

Detecting the separated analytes using UV-Vis absorbance has limited use. This is due to the short optical path length, typically the depth of the microchannel. Z-shaped cells have been successfully explored in research laboratories, but are still less applicable than fluorescence detection. 

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Georgia Institute of Technology Emission Control, Vehicle Traffic Flow Management... 

Hydrogen Effects in Catalysis Fundamentals and Practical Applications, edited by Zoltan Paal and P. G. Menon Flow Management for Engineers and Scientists,... 

A permeable reactive barrier (PRB) is defined as an in situ method for remediating contaminated groundwater that combines a passive chemical or biological treatment zone with subsurface fluid flow management. Treatment media may include zero-valent iron, chelators, sorbents, and microbes to address a wide variety of groundwater contaminants, such as chlorinated solvents, other organics,... 

The slurry flow management scheme to the cells has large numbers of parallel flow paths through the hydrocyclones and through individual electrode cavities. Upsets in these paths can lead to upsets in the quality and quantity of slurry flowing to the electrode cavities, with possible impact on membrane operation. 

Bernd Wagner, Stefan Enzler (Eds.) Material Flow Management 2006. ISBN 3-7908-1591-8... 

LBO financings require a healthy cash flow for interest payments and repayments of debt tranches. The net debt position also determines the equity value that can be realized for financial sponsors on exit. The two major levers for improved cash flow management are working capital management and a disciplined capital expenditure program. 

Flow Management for Engineers and Scienti s, Nicholas P. Chere-misinoff and Paul N. Cheremisinoff... 

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