Experimental and modeling based dead-volume detection for externally stirred tanks

The design of a free piston compressor and an analysis on integrating an external combustion engine into the compressor design are presented in this article. A free piston compressor is a device which converts chemical energy to work on a volume of air through the kinetic energy of an inertia driven piston, which is not rigidly attached to a ground. An external combustion engine serves as in intermediate chamber which transfers combustion gases to a device to perform some work. The following discusses the design and experiments on an external combustion engine, with a focus on eliminating an injection holding force on a free piston compressor’s elastomeric membranes. The efficiency of the external combustion engine to transfer energy without significant losses due to heat, dead volume, air/fuel mixtures, and actuated valve speed are also presented.

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Integrated impedance sensing of liquid sample plug flow enables automated high throughput NMR spectroscopy

Microsystems & Nanoengineering ◽

10.1038/s41378-021-00253-2 ◽

2021 ◽

Vol 7 (1) ◽

Cited By ~ 1

Author(s):

Omar Nassar ◽

Mazin Jouda ◽

Michael Rapp ◽

Dario Mager ◽

Jan G. Korvink ◽

...

Keyword(s):

Nmr Spectroscopy ◽

High Throughput ◽

Plug Flow ◽

Microfluidic System ◽

High Resolution Spectroscopy ◽

Dead Volume ◽

Absolute Difference ◽

Immiscible Fluid ◽

Flow Sensors ◽

Novel Approach

AbstractA novel approach for automated high throughput NMR spectroscopy with improved mass-sensitivity is accomplished by integrating microfluidic technologies and micro-NMR resonators. A flow system is utilized to transport a sample of interest from outside the NMR magnet through the NMR detector, circumventing the relatively vast dead volume in the supplying tube by loading a series of individual sample plugs separated by an immiscible fluid. This dual-phase flow demands a real-time robust sensing system to track the sample position and velocities and synchronize the NMR acquisition. In this contribution, we describe an NMR probe head that possesses a microfluidic system featuring: (i) a micro saddle coil for NMR spectroscopy and (ii) a pair of interdigitated capacitive sensors flanking the NMR detector for continuous position and velocity monitoring of the plugs with respect to the NMR detector. The system was successfully tested for automating flow-based measurement in a 500 MHz NMR system, enabling high resolution spectroscopy and NMR sensitivity of 2.18 nmol s1/2 with the flow sensors in operation. The flow sensors featured sensitivity to an absolute difference of 0.2 in relative permittivity, enabling distinction between most common solvents. It was demonstrated that a fully automated NMR measurement of nine individual 120 μL samples could be done within 3.6 min or effectively 15.3 s per sample.

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Modelling mixing dynamics in uncovered baffled and unbaffled stirred tanks

AIChE Journal ◽

10.1002/aic.17322 ◽

2021 ◽

Author(s):

T. Płusa ◽

J. Talaga ◽

A. Duda ◽

P. Duda

Keyword(s):

Stirred Tanks ◽

Mixing Dynamics

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Air Entrainment in Baffled Stirred Tanks

Chemical Engineering Research and Design ◽

10.1205/cherd06184 ◽

2007 ◽

Vol 85 (5) ◽

pp. 654-664 ◽

Cited By ~ 34

Author(s):

S. Bhattacharya ◽

D. Hebert ◽

S.M. Kresta

Keyword(s):

Air Entrainment ◽

Stirred Tanks

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On-Chip Fabrication of None-Dead-Volume Microtips for ESI-MS Applications

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.121-123.611 ◽

2007 ◽

Vol 121-123 ◽

pp. 611-614

Author(s):

Che Hsin Lin ◽

Jen Taie Shiea ◽

Yen Lieng Lin

Keyword(s):

Surface Tension ◽

Low Cost ◽

Microfluidic Channel ◽

Dead Volume ◽

Esi Ms ◽

Rapid Fabrication ◽

Chip Fabrication ◽

Novel Method ◽

On Chip ◽

Highly Uniform

This paper proposes a novel method to on-chip fabricate a none-dead-volume microtip for ESI-MS applications. The microfluidic chip and ESI tip are fabricated in low-cost plastic based materials using a simple and rapid fabrication process. A constant-speed-pulling method is developed to fabricate the ESI tip by pulling mixed PMMA glue using a 30-μm stainless wire through the pre-formed microfluidic channel. The equilibrium of surface tension of PMMA glue will result in a sharp tip after curing. A highly uniform micro-tip can be formed directly at the outlet of the microfluidic channel with minimum dead-volume zone. Detection of caffeine, myoglobin, lysozyme and cytochrome C biosamples confirms the microchip device can be used for high resolution ESI-MS applications.

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The dead volume effect on the elastic moduli measurements using the forced‐oscillation method

Geophysical Prospecting ◽

10.1111/1365-2478.13173 ◽

2021 ◽

Author(s):

V. Mikhaltsevitch ◽

M. Lebedev ◽

R. Chavez ◽

M. Pervukhina ◽

S. Glubokovskikh ◽

...

Keyword(s):

Elastic Moduli ◽

Forced Oscillation ◽

Volume Effect ◽

Dead Volume ◽

The Dead ◽

Oscillation Method

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A Silicon Micromachined Valve Driven by a Bi-Stable Electromagnetic Actuator

10.1115/imece1999-0271 ◽

1999 ◽

Author(s):

S. Böhm ◽

G. J. Burger ◽

M. T. Korthorst ◽

F. Roseboom

Keyword(s):

Fluid Flow ◽

Silicone Rubber ◽

The Other ◽

Dead Volume ◽

Electromagnetic Actuator ◽

Rubber Sheet ◽

Rubber Layer ◽

Sandwich Construction ◽

The One ◽

Valve Part

Abstract In this contribution a micromachined open/closed valve is presented which is driven by a conventionally manufactured bistable electromagnetic actuator. Basically the micromachined valve part, 7 × 7 × 1 mm3 in dimension, is a sandwich construction of two KOH etched wafers with a specially formulated silicone rubber layer in between. This rubber sheet forms a flexible flow path, which can be open and closed to control a fluid flow. In order to provide a large stroke of about 200 μm, a precision-engineered bi-stable electromagnetic actuator was selected. This actuator consists of a spring-biased armature that can move up and down in a magnetically soft iron housing, incorporating a permanent magnet and a coil. It will be shown that this combination of micromachined and precision-engineered components provides the required low dead volume on the one hand and a large actuator stroke on the other. Another benefit of the application of a bi-stable actuator is the fact that only energy is needed in order to switch between the open and closed state. Moreover, the large stroke makes the valve particle tolerant thus allowing media like cell suspensions and whole blood.

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