Special high speed imaging techniques using phase, aperture, and polarization effects

ABSTRACT The successful investigation of photosensitive and dynamic biological events, such as those in a proliferating tissue or a dividing cell, requires non-intervening high-speed imaging techniques. Electrically tunable lenses (ETLs) are liquid lenses possessing shape-changing capabilities that enable rapid axial shifts of the focal plane, in turn achieving acquisition speeds within the millisecond regime. These human-eye-inspired liquid lenses can enable fast focusing and have been applied in a variety of cell biology studies. Here, we review the history, opportunities and challenges underpinning the use of cost-effective high-speed ETLs. Although other, more expensive solutions for three-dimensional imaging in the millisecond regime are available, ETLs continue to be a powerful, yet inexpensive, contender for live-cell microscopy.

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Optical imaging techniques for hypersonic impulse facilities

The Aeronautical Journal ◽

10.1017/s0001924000001718 ◽

2007 ◽

Vol 111 (1115) ◽

pp. 1-16 ◽

Cited By ~ 9

Author(s):

T. J. McIntyre ◽

H. Kleine ◽

A. F. P. Houwing

Keyword(s):

Optical Imaging ◽

High Speed ◽

Imaging Techniques ◽

Flow Visualisation ◽

Complex Flows ◽

High Speed Imaging ◽

Time Resolved ◽

Flow Parameters ◽

Planar Laser ◽

Recent Developments

Abstract The application of optical imaging techniques to hypersonic facilities is discussed and examples of experimental measurements are provided. Traditional Schlieren and shadowgraph techniques still remain as inexpensive and easy to use flow visualisation techniques. With the advent of faster cameras, these methods are becoming increasingly important for time-resolved high-speed imaging. Interferometry’s quantitative nature is regularly used to obtain density information about hypersonic flows. Recent developments have seen an extension of the types of flows that can be imaged and the measurement of other flow parameters such as ionisation level. Planar laser induced fluorescence has been used to visualise complex flows and to measure such quantities as temperature and velocity. Future directions for optical imaging are discussed.

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Investigation of Auto-Ignition of a Pulsed Methane Jet in Vitiated Air Using High-Speed Imaging Techniques

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4002014 ◽

2010 ◽

Vol 133 (2) ◽

Cited By ~ 11

Author(s):

W. Meier ◽

I. Boxx ◽

C. Arndt ◽

M. Gamba ◽

N. Clemens

Keyword(s):

High Speed ◽

Gas Flow ◽

Imaging Techniques ◽

Frame Rate ◽

Experimental Arrangement ◽

Single Shot ◽

Exhaust Gas ◽

High Speed Imaging ◽

Auto Ignition ◽

Flow Field Characteristics

An experimental arrangement for the investigation of auto-ignition of a pulsed CH4 jet in a coflow of hot exhaust gas from a laminar lean premixed H2/air flame at atmospheric pressure is presented. The ignition events were captured by high-speed imaging of the OH∗ chemiluminescence associated with the igniting flame kernels at a frame rate of 5 kHz. The flow-field characteristics were determined by high-speed particle image velocimetry and Schlieren images. Furthermore, high-speed imaging of laser-induced fluorescence of OH was applied to visualize the exhaust gas flow and the ignition events. Auto-ignition was observed to occur at the periphery of the CH4 jet with high reproducibility in different runs concerning time and location. In each measurement run, several hundred consecutive single shot images were recorded from which sample images are presented. The main goals of the study are the presentation of the experimental arrangement and the high-speed measuring systems and a characterization of the auto-ignition events occurring in this system.

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Ethanol effects on cardiomyocyte contractility

Clinical Science ◽

10.1042/cs0980401 ◽

2000 ◽

Vol 98 (4) ◽

pp. 401-407 ◽

Cited By ~ 10

Author(s):

Leanne M. D. DELBRIDGE ◽

Pamela J. CONNELL ◽

Peter J. HARRIS ◽

Trefor O. MORGAN

Keyword(s):

High Speed ◽

Imaging Techniques ◽

Cardiac Contractility ◽

Ethanol Exposure ◽

High Speed Imaging ◽

Low Concentrations ◽

Cardiomyocyte Contractility ◽

Contraction Cycle ◽

Kinetics Of

Little is known about the direct cardiac effects of socially common sub-intoxication levels of ethanol. Previous studies evaluating the responses of normal cardiomyocytes to short-term ethanol exposure have utilized ethanol concentrations equivalent to extreme intoxication or lethal levels in vivo. The purpose of the present study was to investigate the contractile responses of isolated rat ventricular cardiomyocytes during exposure to relatively low concentrations of ethanol in the range 0.05–0.5% (v/v) (8.6–86 mM) under physiological conditions (3 Hz stimulation; 36 °C; BSA vehicle). High-speed imaging techniques were used to study the kinetics of myocyte contraction, and shortening parameters were calculated for mechanistic evaluation. The concentration–response relationship was not linear and exhibited two plateau phases, suggesting at least two mechanisms of action of ethanol on cardiomyocyte contraction. At 0.05% (8.6 mM), ethanol treatment produced a 14.4% decrease in maximum myocyte shortening. The maximum rates of cell shortening and lengthening were similarly impaired, but there was no effect on contraction cycle timing at this low concentration. At 0.30% (51 mM), ethanol reduced maximum shortening by 40.2%, prolonged excitation–contraction coupling latency and abbreviated the contraction cycle time by 38%. The inotropic modulatory effect of ethanol was exaggerated in the absence of protein in the superfusion buffer. This is the first report which identifies ethanol at 0.05% (v/v) as a modulator of cardiac contractility. Kinetic analyses indicate that the mechanism of action involves disturbance of sarcoplasmic reticulum function, and this may contribute to arrhythmogenic vulnerability – especially in an in vivo context of heightened compensatory sympathetic drive.

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Langevin dynamics encapsulate the microscopic and emergent macroscopic properties of midge swarms

Journal of The Royal Society Interface ◽

10.1098/rsif.2017.0806 ◽

2018 ◽

Vol 15 (138) ◽

pp. 20170806 ◽

Cited By ~ 7

Author(s):

A. M. Reynolds

Keyword(s):

High Speed ◽

Imaging Techniques ◽

Condensed Phases ◽

Global Order ◽

High Speed Imaging ◽

Fish Schools ◽

Static Testing ◽

Swarm Dynamics ◽

Future Experimentation ◽

Promising Avenue

In contrast to bird flocks, fish schools and animal herds, midge swarms maintain cohesion but do not possess global order. High-speed imaging techniques are now revealing that these swarms have surprising properties. Here, I show that simple models found on the Langevin equation are consistent with this wealth of recent observations. The models predict correctly that large accelerations, exceeding 10 g, will be common and they predict correctly the coexistence of core condensed phases surrounded by dilute vapour phases. The models also provide new insights into the influence of environmental conditions on swarm dynamics. They predict that correlations between midges increase the strength of the effective force binding the swarm together. This may explain why such correlations are absent in laboratory swarms but present in natural swarms which contend with the wind and other disturbances. Finally, the models predict that swarms have fluid-like macroscopic mechanical properties and will slosh rather than slide back and forth after being abruptly displaced. This prediction offers a promising avenue for future experimentation that goes beyond current quasi-static testing which has revealed solid-like responses.

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Characteristics of Boiling Heat Transfer on Hydrophobic Surface

EPJ Web of Conferences ◽

10.1051/epjconf/201919600054 ◽

2019 ◽

Vol 196 ◽

pp. 00054 ◽

Cited By ~ 1

Author(s):

Anton Surtaev ◽

Vladimir Serdyukov ◽

Alexey Safonov

Keyword(s):

Heat Transfer ◽

Contact Line ◽

High Speed ◽

Imaging Techniques ◽

Video Recording ◽

Nucleation Site ◽

High Speed Imaging ◽

Site Density ◽

Fluoropolymer Coating ◽

Nucleation Site Density

The paper presents the results of an experimental study of the effect of hydrophobic fluoropolymer coating on the multiscale characteristics of heat transfer at water boiling. New experimental data on dynamics of vapor bubble growth and detachment, evolution of contact line, nucleation site density, heat transfer coefficient were obtained using high-speed imaging techniques, including infrared thermography and video recording from the bottom side of transparent ITO heater. It was shown, that the using of hydrophobic fluoropolymer coating leads to heat transfer enhancement, to decrease of the superheat temperature at the onset of boiling, to increase of the active nucleation site density and to significant change in the dynamics of growth and departure of vapor bubbles and the evolution of the triple contact line.

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