Thermal-Fluid Phenomena Induced by Nanosecond-Pulse Heating of Materials in Water

2001 ◽  
Vol 123 (6) ◽  
pp. 1123-1132 ◽  
Author(s):  
I. Ueno ◽  
M. Shoji
Keyword(s):  
High Speed ◽  
Bubble Formation ◽  
Water System ◽  
Solid Material ◽  
Laser Wavelength ◽  
High Speed Photography ◽  
Time Resolved ◽  
Pump And Probe ◽  
Shock Wave Generation ◽  
Speed Up

Thermal-hydraulic phenomena adjacent to the liquid metal-water and solid material-water interfaces induced by nanosecond pulsed Nd:YAG laser (wavelength: 532 nm, FWHM: ∼13 ns) heating with the fluence F of 5.0×101∼1.0×103 mJ/cm2 were experimentally investigated. By applying the high-speed photography with a frame speed up to 2.0×107 fps, the aspects of the bubble formation, shock wave generation and propagation were observed. The bubble formation on the heated material’s surface of about 80 nm in diameter was detected in Si-water system from the time-resolved reflection (TRR) signal by applying the pump and probe method.

Time-Resolved Micro Liquid Desorption Mass Spectrometry: Mechanism, Features, and Kinetic Applications

2006 ◽  
Vol 59 (2) ◽  
pp. 81 ◽  
Author(s):  
Ales Charvat ◽  
Andreas Bógehold ◽  
Bernd Abel
Keyword(s):  
Mass Spectrometry ◽  
Liquid Phase ◽  
High Speed ◽  
High Performance ◽  
Kinetic Studies ◽  
Solution Concentration ◽  
Bulk Water ◽  
Laser Wavelength ◽  
Time Resolved ◽  
Desorption Mass Spectrometry

Liquid water beam desorption mass spectrometry is an intriguing technique to isolate charged molecular aggregates directly from the liquid phase and to analyze them employing sensitive mass spectrometry. The liquid phase in this approach consists of a 10 µm diameter free liquid filament in vacuum which is irradiated by a focussed infrared laser pulse resonant with the OH-stretch vibration of bulk water. Depending upon the laser wavelength, charged (e.g. protonated) macromolecules are isolated from solution through a still poorly characterized mechanism. After the gentle liquid-to-vacuum transfer the low-charge-state aggregates are analyzed using time-of-flight mass spectrometry. A recent variant of the technique uses high performance liquid chromatography valves for local liquid injections of samples in the liquid carrier beam, which enables very low sample consumption and high speed sample analysis. In this review we summarize recent work to characterize the ‘desorption’ or ion isolation mechanism in this type of experiment. A decisive and interesting feature of micro liquid beam desorption mass spectrometry is that — under certain conditions — the gas-phase mass signal for a large number of small as well as supramolecular systems displays a surprisingly linear response on the solution concentration over many orders of magnitude, even for mixtures and complex body fluids. This feature and the all-liquid state nature of the technique makes this technique a solution-type spectroscopy that enables real kinetic studies involving (bio)polymers in solution without the need for internal standards. Two applications of the technique monitoring enzyme digestion of proteins and protein aggregation of an amyloid model system are highlighted, both displaying its potential for monitoring biokinetics in solution.

Research of bubble flow characteristics in microfluidic chip

2017 ◽  
Vol 31 (10) ◽  
pp. 1750109
Author(s):  
Chao Qiu ◽  
Han Cheng ◽  
Shuxian Chen
Keyword(s):  
Heat Flux ◽  
Microfluidic Chip ◽  
High Speed ◽  
Flow Characteristics ◽  
Hydrophobic Surface ◽  
High Speed Photography ◽  
Bubble Flow ◽  
Hydrophilic Surface ◽  
Biological Detection ◽  
Speed Up

Bubble is the heart of the microfluidic chip, which takes a significant role in drug release, biological detection and so on. In this case, bubble flow characteristics in microfluidic chip are the key to realize its function. In this paper, bubble flow characteristics in the microfluidic chip have been studied with high speed photography system by controlling the wettability and the heat flux of the microelectrode surface. The result shows that bubble flows faster on the electrode with hydrophobic surface. In addition, loading current to the electrode with hydrophilic surface could also speed up the movement of bubble, and the flow rate of bubble increases with the increasing heat flux of the electrode.

Vibration Mechanisms of a Heated Rod Due to Subcooled Boiling Flow

2006 ◽  
Author(s):  
M. R. Nematollahi ◽  
M. H. Akbari
Keyword(s):  
Quantitative Estimate ◽  
High Speed ◽  
Bubble Formation ◽  
Heating Surface ◽  
High Speed Photography ◽  
Subcooled Boiling ◽  
Bubble Behavior ◽  
Boiling Flow ◽  
Excitation Force ◽  
Power Densities

Vibration characteristics of subcooled boiling flow on thin and long structures such as a heating rod were recently investigated by the authors. The results show that the intensity of the subcooled boiling-induced vibration (SBIV) was influenced strongly by the conditions of subcooling temperature, linear power density and flow velocity. Implosive bubble formation and collapse are the main nature of subcooled boiling, and their behavior are the only sources to originate SBIV. Therefore, in order to explain the phenomenon of SBIV, it is essential to obtain reliable information about bubble behavior in subcooled boiling conditions. This was investigated at different conditions of coolant subcooling temperatures of 25 to 75°C, coolant flow velocities of 16 to 53 cm/s, and linear power densities of 100 to 600 W/cm. High speed photography at 13,500 frames per second was performed at these conditions. The results show that even at the highest subcooling condition, the absolute majority of bubbles collapse very close to the surface after detaching from the heating surface. Based on these observations, a simple model of surface tension and momentum change is introduced to offer a rough quantitative estimate of the force exerted on the heating surface. The formation of a typical bubble in subcooled boiling is predicted to exert an excitation force in the order of 10−4 N.

scholarly journals High-Speed Flow Visualization of a Canonical Airblast Atomizer Using Synchrotron X-Rays

2019 ◽  
Author(s):  
Theodore J. Heindel ◽  
Timothy B. Morgan ◽  
Thomas J. Burtnett ◽  
Julie K. Bothell ◽  
Danyu Li ◽  
...  
Keyword(s):  
High Speed ◽  
Near Field ◽  
National Laboratory ◽  
Bubble Formation ◽  
Liquid Core ◽  
Argonne National Laboratory ◽  
Operating Conditions ◽  
X Rays ◽  
Time Resolved ◽  
Spray Formation

Abstract Liquid sprays play a key role in many engineering processes and the dynamics at the nozzle exit have a significant impact on the downstream spray characteristics. However, visualizing the spray in this region is extremely challenging because, under most operating conditions, the spray is optically dense. High intensity white beam X-rays, like those found at the Advanced Photon Source (APS) at Argonne National Laboratory, can be used to produce time-resolved measurements of the liquid-gas structures in the spray near-field region. In this study, high temporal and spatial resolution X-ray images were acquired at the 7-BM beamline at APS of an atomization process using a canonical airblast atomizer consisting of coaxial liquid and gas jets. Unique flow structures were observed under various operating conditions, including bag, ligament, wisp, droplet, and air bubble formation, as well as hollowing of the liquid core into a crown at the liquid needle exit. Conditions where these structures exist are presented and their impact on spray formation are discussed.

Application Of High-Speed Photography To Time-Resolved Wavefront Measurement

1988 ◽  
Author(s):  
D. R. Neal ◽  
W. C. Sweatt ◽  
W. J. Alford ◽  
D. A. McArthur ◽  
G. N. Hays
Keyword(s):  
High Speed ◽  
High Speed Photography ◽  
Time Resolved ◽  
Wavefront Measurement

scholarly journals Characterisation of the impact response of energetic materials: observation of a low-level reaction in 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

RSC Advances ◽  
2016 ◽  
Vol 6 (33) ◽  
pp. 27896-27900 ◽  
Author(s):  
David M. Williamson ◽  
Sue Gymer ◽  
Nicholas E. Taylor ◽  
Stephen M. Walley ◽  
Andrew P. Jardine ◽  
...  
Keyword(s):  
Optical Spectroscopy ◽  
Energetic Materials ◽  
High Speed ◽  
Impact Response ◽  
High Speed Photography ◽  
High Explosives ◽  
Time Resolved ◽  
Optical Radiometry ◽  
Integrated Diagnostics ◽  
The Impact

Time resolved and integrated diagnostics including high speed photography, mass and optical spectroscopy, and optical-radiometry used to study impact response of high explosives in far more detail than possible with conventional sensitiveness tests.

scholarly journals Synthetic jet generation by high-frequency cavitation

2017 ◽  
Vol 823 ◽  
Author(s):  
Milad Mohammadzadeh ◽  
Silvestre Roberto Gonzalez-Avila ◽  
Kun Liu ◽  
Qi Jie Wang ◽  
Claus-Dieter Ohl
Keyword(s):  
High Frequency ◽  
Laser Power ◽  
High Speed ◽  
Bubble Formation ◽  
Acoustic Streaming ◽  
High Repetition Rate ◽  
Synthetic Jet ◽  
Bubble Collapse ◽  
High Speed Photography ◽  
Bubble Interactions

Cavitation bubbles are nucleated at a high repetition rate in water by delivering a pulsed laser through a fibre optic. Continuous high-frequency cavitation drives a stream away from the fibre tip. Using high-speed photography and particle image velocimetry, the stream is characterised as a synthetic jet, generated by trains of vortices induced by non-spherical bubble collapse. At low laser power, the bubbles collapse before the arrival of a subsequent laser pulse. Yet, by increasing the laser power, a system of bubbles is formed which leads to complex bubble–bubble interactions. The synthetic jet is observed regardless of the bubble formation regime, demonstrating the stability of the phenomenon. Synthetic jet generation by repetitive bubble collapse extends the well-studied acoustic streaming from small-amplitude bubble oscillations.

A Study of Bubble Departure in Forced-Convection Boiling

1968 ◽  
Vol 90 (2) ◽  
pp. 223-230 ◽  
Author(s):  
N. Koumoutsos ◽  
R. Moissis ◽  
A. Spyridonos
Keyword(s):  
Forced Convection ◽  
Liquid Flow ◽  
High Speed ◽  
Water System ◽  
Heating Surface ◽  
Nucleate Boiling ◽  
High Speed Photography ◽  
Spherical Bubble ◽  
Velocity Relationship ◽  
Departure Size

Visual observations in a boiling liquid flow indicate that, as the flow velocity is increased, the size of bubbles leaving the heating surface decreases. The purpose of this investigation is to arrive at a criterion for bubble departure in forced-convection nucleate boiling. Photographic studies indicate that a little before departure a “neck” is formed joining the almost spherical bubble to the heating surface. From a consideration of the hydrodynamic stability of the bubble-and-neck model, the departure-size-to-velocity relationship may be predicted. Measured departure radii in a forced-convection boiling water system taken by means of high-speed photography are satisfactorily correlated with the results derived analytically.

Scanning x-ray fluorescence microscopy and principal component analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1752-1753
Author(s):  
Brian Cross
Keyword(s):  
Principal Component Analysis ◽  
Fluorescence Microscopy ◽  
Spatial Resolution ◽  
High Speed ◽  
Image Acquisition ◽  
Principal Component ◽  
Fluorescence Microscope ◽  
Acquisition Rate ◽  
X Ray ◽  
Speed Up

A relatively new entry, in the field of microscopy, is the Scanning X-Ray Fluorescence Microscope (SXRFM). Using this type of instrument (e.g. Kevex Omicron X-ray Microprobe), one can obtain multiple elemental x-ray images, from the analysis of materials which show heterogeneity. The SXRFM obtains images by collimating an x-ray beam (e.g. 100 μm diameter), and then scanning the sample with a high-speed x-y stage. To speed up the image acquisition, data is acquired "on-the-fly" by slew-scanning the stage along the x-axis, like a TV or SEM scan. To reduce the overhead from "fly-back," the images can be acquired by bi-directional scanning of the x-axis. This results in very little overhead with the re-positioning of the sample stage. The image acquisition rate is dominated by the x-ray acquisition rate. Therefore, the total x-ray image acquisition rate, using the SXRFM, is very comparable to an SEM. Although the x-ray spatial resolution of the SXRFM is worse than an SEM (say 100 vs. 2 μm), there are several other advantages.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

Sign in / Sign up

Export Citation Format

Share Document