High-speed air microjet arrays produced using acoustic streaming for micro propulsion

2013 ◽  
Author(s):  
Seow Yuen Yee ◽  
Rebecca L. Peterson ◽  
Luis P. Bernal ◽  
Khalil Najafi
Keyword(s):  
High Speed ◽  
Acoustic Streaming ◽  
Micro Propulsion

scholarly journals Gold-implanted plasmonic quartz plate as a launch pad for laser-driven photoacoustic microfluidic pumps

2019 ◽  
Vol 116 (14) ◽  
pp. 6580-6585 ◽  
Author(s):  
Shuai Yue ◽  
Feng Lin ◽  
Qiuhui Zhang ◽  
Njumbe Epie ◽  
Suchuan Dong ◽  
...  
Keyword(s):  
High Speed ◽  
Microelectromechanical Systems ◽  
Acoustic Streaming ◽  
Fluid Motion ◽  
Quartz Plate ◽  
Ultrasound Wave ◽  
High Speed Imaging ◽  
Driving Mechanisms ◽  
Easy Integration ◽  
Microfabrication Techniques

Enabled initially by the development of microelectromechanical systems, current microfluidic pumps still require advanced microfabrication techniques to create a variety of fluid-driving mechanisms. Here we report a generation of micropumps that involve no moving parts and microstructures. This micropump is based on a principle of photoacoustic laser streaming and is simply made of an Au-implanted plasmonic quartz plate. Under a pulsed laser excitation, any point on the plate can generate a directional long-lasting ultrasound wave which drives the fluid via acoustic streaming. Manipulating and programming laser beams can easily create a single pump, a moving pump, and multiple pumps. The underlying pumping mechanism of photoacoustic streaming is verified by high-speed imaging of the fluid motion after a single laser pulse. As many light-absorbing materials have been identified for efficient photoacoustic generation, photoacoustic micropumps can have diversity in their implementation. These laser-driven fabrication-free micropumps open up a generation of pumping technology and opportunities for easy integration and versatile microfluidic applications.

High-speed imaging of an ultrasound-driven bubble in contact with a wall: “Narcissus” effect and resolved acoustic streaming

2005 ◽  
Vol 41 (2) ◽  
pp. 147-153 ◽  
Author(s):  
Philippe Marmottant ◽  
Michel Versluis ◽  
Nico de Jong ◽  
Sascha Hilgenfeldt ◽  
Detlef Lohse
Keyword(s):  
High Speed ◽  
Acoustic Streaming ◽  
High Speed Imaging

Comparison of Convective and Radiative Heating Modes on the Thermophysical Changes of a Cerium Nitrate Droplet

2015 ◽  
Vol 8 (1) ◽  
Author(s):  
Binita Pathak ◽  
Saptarshi Basu
Keyword(s):  
High Speed ◽  
Reaction Rate ◽  
Laser Intensity ◽  
Monochromatic Light ◽  
Acoustic Streaming ◽  
Radiative Heating ◽  
Cerium Nitrate ◽  
Speed Flow ◽  
Levitated Droplet ◽  
Rate Formulation

In this paper, we try to establish the equivalence or similarity in the thermal and physiochemical changes in precursor droplets (cerium nitrate) in convective and radiative fields. The radiative field is created through careful heating of the droplet using a monochromatic light source (CO2 laser). The equivalence is also established for different modes of convection like droplet injected into a high-speed flow and droplet experiencing a convective flow due to acoustic streaming (levitated) only. The thermophysical changes are studied in an aqueous cerium nitrate droplet, and the dissociation of cerium nitrate to ceria is modeled using modified Kramers' reaction rate formulation. It is observed that vaporization, species accumulation, and chemical characteristics obtained in a convectively heated droplet are retained in a radiatively heated droplet by careful adjustment of the laser intensity. The timescales and ceria yield match reasonably well for both the cases. It is also noted that similar conclusions are drawn in both levitated droplet and a nonlevitated droplet.

Enhancement of Natural Convection and Pool Boiling Heat Transfer via Ultrasonic Vibration

2003 ◽  
Author(s):  
Ho-Young Kim ◽  
Yi Gu Kim ◽  
Byung Ha Kang
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Ultrasonic Vibration ◽  
Boiling Heat Transfer ◽  
High Speed ◽  
Imaging System ◽  
Flow Behavior ◽  
Pool Boiling ◽  
Acoustic Streaming ◽  
Pool Boiling Heat Transfer

This work experimentally studies the fundamental mechanism by which the ultrasonic vibration enhances natural convection and pool boiling heat transfer. A thin platinum wire is used as both a heat source and a temperature sensor. A high speed video imaging system is employed to observe the behavior of cavitation and thermal bubbles. Experimental results show that the effects of ultrasonic vibration on flow behavior are vastly different depending on the heat transfer regime and the amount of dissolved gas. In the natural convection and subcooled boiling regimes, behavior of cavitation bubbles strongly affects the degree of heat transfer enhancement. In saturated boiling, no cavitation occurs thus the reduced thermal bubble size at departure and acoustic streaming are major factors enhancing heat transfer rate. The highest enhancement ratio is obtained in natural convection regime where no bubbles are present without ultrasonic vibration.

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.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

An atomic-resolution microscope study of Al contracts on GaAs

1986 ◽  
Vol 44 ◽  
pp. 726-727
Author(s):  
Z. Liliental-Weber ◽  
C. Nelson ◽  
R. Ludeke ◽  
R. Gronsky ◽  
J. Washburn
Keyword(s):  
High Speed ◽  
Schottky Contacts ◽  
Detailed Knowledge ◽  
The Past ◽  
Semiconductor Interfaces ◽  
Deposited Metal ◽  
Microwave Applications ◽  
Free Interfaces ◽  
Potential Use

The properties of metal/semiconductor interfaces have received considerable attention over the past few years, and the Al/GaAs system is of special interest because of its potential use in high-speed logic integrated optics, and microwave applications. For such materials a detailed knowledge of the geometric and electronic structure of the interface is fundamental to an understanding of the electrical properties of the contact. It is well known that the properties of Schottky contacts are established within a few atomic layers of the deposited metal. Therefore surface contamination can play a significant role. A method for fabricating contamination-free interfaces is absolutely necessary for reproducible properties, and molecularbeam epitaxy (MBE) offers such advantages for in-situ metal deposition under UHV conditions

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