AC electric field controlled non-Newtonian filament thinning and droplet formation on the microscale

Lab on a Chip ◽  
2017 ◽  
Vol 17 (17) ◽  
pp. 2969-2981 ◽  
Author(s):  
Y. Huang ◽  
Y. L. Wang ◽  
T. N. Wong
Keyword(s):  
Flow Field ◽  
Electric Field ◽  
Newtonian Fluid ◽  
High Speed ◽  
Droplet Formation ◽  
Particle Imaging Velocimetry ◽  
Ac Electric Field ◽  
Formation Dynamics ◽  
Particle Imaging ◽  
First Time

We investigate the AC electric field controlled filament thinning and droplet formation dynamics of one non-Newtonian fluid. Furthermore, for the first time, we quantitatively measure the flow field of the non-Newtonian droplet formation under the influence of AC electric field, via a high-speed micro particle imaging velocimetry (μPIV) system. We discover the viscoelasticity contributes to the discrepancies majorly.

scholarly journals An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

2000 ◽  
Vol 123 (2) ◽  
pp. 418-428 ◽  
Author(s):  
Mark P. Wernet ◽  
Michelle M. Bright ◽  
Gary J. Skoch
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Transient Flow ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Transient Pressure ◽  
Pressure Transducers ◽  
Stable Operating ◽  
Particle Imaging

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

scholarly journals Linear Assembles of BN Nanosheets, Fabricated in Polymer/BN Nanosheet Composite Film

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Hong-Baek Cho ◽  
Tadachika Nakayama ◽  
Tsuneo Suzuki ◽  
Satoshi Tanaka ◽  
Weihua Jiang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electric Field ◽  
Composite Film ◽  
High Speed ◽  
Film Plane ◽  
Digital Microscopy ◽  
X Ray Diffraction ◽  
High Anisotropy ◽  
Dc Electric Field ◽  
First Time

Linear assembles of BN nanosheets (LABNs) were fabricated in polysiloxane/BN nanosheet composite film under a high DC electric field. The hexagonal BN nanosheets were dispersed by sonication in a prepolymer mixture of polysiloxane followed by a high-speed mixing. The homogeneous suspension was cast on a spacer of microscale thickness and applied to a high DC electric field before it became cross-linked. X-ray diffraction, scanning electron microscopy, and digital microscopy revealed that LABNs formed in the polysiloxane matrix and that the BN nanosheets in the LABNs were aligned perpendicular to the film plane with high anisotropy. This is the first time that linear assemblies of nanosheets have been fabricated in an organic-inorganic hybrid film by applying a DC electric field. The enhanced thermal conductivity of the composite film is attributed to the LABNs. The LABN formation and heat conduction mechanisms are discussed. The polysiloxane/BN nanosheet composite film has the potential to be used semiconductor applications that require both a high thermal conductivity and a high electric insulation.

THE INTERACTION BETWEEN ELECTRORHEOLOGICAL PARTICLES IN AC ELECTRIC FIELD STUDIED USING OPTICAL TWEEZERS

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2300-2306
Author(s):  
J. XU ◽  
X. DONG ◽  
Z. Y. CHEN ◽  
Y. G. JIANG ◽  
L. W. ZHOU
Keyword(s):  
Image Processing ◽  
Electric Field ◽  
Optical Tweezers ◽  
High Speed ◽  
Sampling Rate ◽  
Interaction Strength ◽  
Processing System ◽  
Dipole Interaction ◽  
High Speed Imaging ◽  
Ac Electric Field

The dipole interaction between a pair of electrorheological (ER) particles under an external AC electric field was confirmed in a dynamic case using optical tweezers positioning and a system of high speed imaging and image processing. By measuring the interactions between two micron-sized ER particles with both central distance and structure forming time, the structure response time and the interaction strength were obtained for the particles under an AC electric field. The spacial resolution of the optical tweezers-high speed imaging-image processing system is 0.26μm. The sampling rate of the high-speed video recorder is up to 8000 frame/s with the corresponding time resolution being 0.125 ms.

scholarly journals Experimental Investigations of Flow Field and Atomization Field Characteristics of Pre-Filming Air-Blast Atomizers

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2800 ◽  
Author(s):  
Xiongjie Fan ◽  
Cunxi Liu ◽  
Yong Mu ◽  
Kaixing Wang ◽  
Yulan Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Liquid Film ◽  
High Speed ◽  
Experimental Investigations ◽  
Mass Rate ◽  
Air Blast ◽  
Air Mass ◽  
Fuel Mass ◽  
Field Organization ◽  
Particle Imaging

Flow field, atomization field characteristics, and liquid film breakup behaviors of a pre-filming air-blast atomizer are investigated using PIV (Particle Imaging Velocimetry), PLIF (Fuel Planar Laser Induced Fluorescence), and high-speed shadowgraph technique under different air mass rates (ma), fuel mass rates (mf), and fuel temperatures (T). The influence of structures constituting the pre-filming air-blast atomizer on the flow field organization and atomization field organization are investigated too. The results illustrate that air-blast atomizer structures have a great difference on the flow fields and atomization fields. Air-blast atomizer structures have great differences on the liquid film breakup processes too. Flow field structure and atomization structure are mainly determined by the swirler structure, whereas there are seldom influences of air mass rate and fuel mass rate on them. The results of the mechanisms of flow field organization and atomization field organization in this study can be used to support the design of new low-emission combustor.

scholarly journals Novel method for immunofluorescence staining of mammalian eggs using non-contact alternating-current electric-field mixing of microdroplets

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Hiromitsu Shirasawa ◽  
Jin Kumagai ◽  
Emiko Sato ◽  
Katsuya Kabashima ◽  
Yukiyo Kumazawa ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Alternating Current ◽  
Immunofluorescence Staining ◽  
Ac Electric Field ◽  
Novel Method ◽  
A New Technique ◽  
Antigen Antibody ◽  
First Time ◽  
Mammalian Eggs

Abstract Recently, a new technique was developed for non-catalytically mixing microdroplets. In this method, an alternating-current (AC) electric field is used to promote the antigen–antibody reaction within the microdroplet. Previously, this technique has only been applied to histological examinations of flat structures, such as surgical specimens. In this study, we applied this technique for the first time to immunofluorescence staining of three-dimensional structures, specifically, mammalian eggs. We diluted an antibody against microtubules from 1:1,000 to 1:16,000 and compared the chromatic degree and extent of fading across dilutions. In addition, we varied the frequency of AC electric-field mixing from 5 Hz to 46 Hz and evaluated the effect on microtubule staining. Microtubules were more strongly stained after AC electric-field mixing for only 5 minutes, even when the concentration of primary antibody was 10 times lower than in conventional methods. AC electric-field mixing also alleviated microtubule fading. At all frequencies tested, AC electric-field mixing resulted in stronger microtubule staining than in controls. There was no clear difference in a microtubule staining between frequencies. These results suggest that the novel method could reduce antibody consumption and shorten immunofluorescence staining time.

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