Experimental study of high-speed imaging detection system for small bubbles in water

2015 ◽  
Author(s):  
Peng Du ◽  
Kecheng Yang ◽  
Min Xia ◽  
Wei Li
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Detection System ◽  
High Speed Imaging ◽  
Imaging Detection ◽  
Small Bubbles

Experimental study of fibre breakup and shot formation in melt blowing nozzle designs

2020 ◽  
pp. 152808372094927 ◽  
Author(s):  
Ignacio Formoso ◽  
Alejandro Rivas ◽  
Gerardo Beltrame ◽  
Gorka S Larraona ◽  
Juan Carlos Ramos ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Flux Ratio ◽  
Adhesive Bond ◽  
Operating Conditions ◽  
Nozzle Geometry ◽  
Dimensionless Temperature ◽  
Melt Blowing ◽  
High Speed Imaging ◽  
Adhesive Bonds

The high demand for quality in the manufacture of absorbent hygiene products requires the adhesive bonds between layers to be as uniform as possible. An experimental study was conducted on two industrial multihole melt blowing nozzle designs used for hot-melt adhesive applications for hygiene products, in order to study two defects that influence the quality of the adhesive bond: fibre breakup, resulting in contamination, and the presence of shots, undesirable lumps that end up in the finished product. To this end, the fibre dynamics were captured at the nozzle exit region by using high-speed imaging. From the results it was observed that die drool is the main source of shot formation, while fibre breakup occurs as a result of applying a sufficiently large force in the direction perpendicular to the fibre. In addition, three dimensionless parameters were defined, the first two being the air-polymer flux ratio and the dimensionless temperature ratio, both of which represent the operating conditions, and the remaining one being the force ratio, which represents the nozzle geometry. The effect of these parameters on fibre breakup and shot formation was studied and the results indicate that both the operating conditions and the nozzle geometry were responsible for the onset of the fibre breakup and for the formation of shots. More precisely, both defects turned out to be dominated by the air-polymer flux ratio and the air tilt angle. The results that emerge from this study are useful for the enhancement of industrial melt blowing nozzles.

Fragmentation of acoustically levitating droplets by laser-induced cavitation bubbles

2016 ◽  
Vol 805 ◽  
pp. 551-576 ◽  
Author(s):  
Silvestre Roberto Gonzalez Avila ◽  
Claus-Dieter Ohl
Keyword(s):  
Shock Wave ◽  
Experimental Study ◽  
Surface Tension ◽  
Cavitation Bubble ◽  
High Speed ◽  
Size Range ◽  
Sound Field ◽  
Negative Pressures ◽  
Impulsive Pressure ◽  
Small Bubbles

We report on an experimental study on the dynamics and fragmentation of water droplets levitated in a sound field exposed to a single laser-induced cavitation bubble. The nucleation of the cavitation bubble leads to a shock wave travelling inside the droplet and reflected from pressure release surfaces. Experiments and simulations study the location of the high negative pressures inside the droplet which result into secondary cavitation. Later, three distinct fragmentation scenarios are observed: rapid atomization, sheet formation and coarse fragmentation. Rapid atomization occurs when the expanding bubble, still at high pressure, ruptures the liquid film separating the bubble from the surrounding air and a shock wave is launched into the surrounding air. Sheet formation occurs due to the momentum transfer of the expanding bubble; for sufficiently small bubbles, the sheet retracts because of surface tension, while larger bubbles may cause the fragmentation of the sheet. Coarse fragmentation is observed after the first collapse of the bubble, where high-speed jets emanate from the surface of the droplet. They are the result of surface instability of the droplet combined with the impulsive pressure generated during collapse. A parameter plot for droplets in the size range between 0.17 and 1.5 mm and laser energies between 0.2 and 4.0 mJ allows the separation of these three regimes.

Experimental study on the hot-melt adhesive pattern produced by melt blowing nozzle designs

2020 ◽  
pp. 152808372097840
Author(s):  
Ignacio Formoso ◽  
Alejandro Rivas ◽  
Gerardo Beltrame ◽  
Gorka S Larraona ◽  
Juan Carlos Ramos ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Adhesive Bond ◽  
Operating Conditions ◽  
Nozzle Geometry ◽  
Dimensionless Temperature ◽  
Melt Blowing ◽  
High Speed Imaging ◽  
Melt Adhesives ◽  
Hot Melt

The high-quality standards of bodily absorbent hygiene products require that the adhesive bond between layers be as uniform and consistent as possible. The final adhesive pattern of the product is determined by the dynamics of the adhesive fibre, which in turn depends on the nozzle geometry and on its operating conditions. In order to gain a better understanding of the dynamics of adhesive fibres and the deposited application pattern, an experimental study was conducted on two multi-hole melt blowing (MB) nozzles designed for producing hot-melt adhesives. To this end, the fibre dynamics were captured through the use of high-speed imaging (HSI). The main parameters that govern the fibre dynamics, including its frequency of oscillation, were quantified through use of image analysis. The effect of the operating conditions on the fibre’s frequency of oscillation at the nozzle exit region was studied and the results indicate that increasing air-polymer flux ratios [Formula: see text] and decreasing dimensionless temperature ratios [Formula: see text] both increase the fibre whipping frequency. Additionally, information on the fibre dynamics on the two planes of oscillation is obtained by studying the deposited application pattern of hot-melt applications. Other related matters are also treated throughout the article, such as fibre contact in adhesive patterns, which represent one of the major defects that the melt blowing technology of hot-melt adhesives is trying to mitigate. Experimental measurements are presented throughout the article to support the validity of the conclusions.

Amplitude Estimation Technique for Intermittent Contact Atomic Force Microscopy

2017 ◽  
Vol 6 (2) ◽  
pp. 29-42
Author(s):  
Grzegorz Dobiński ◽  
Sławomir Pawłowski ◽  
Marek Smolny
Keyword(s):  
Atomic Force Microscopy ◽  
High Speed ◽  
Detection System ◽  
Measurement Techniques ◽  
Estimation Method ◽  
High Speed Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Amplitude Estimation ◽  
Intermittent Contact

This article describes how one of the biggest challenges in designing of high-speed intermittent contact atomic force microscope (AFM) is the construction of a fast amplitude detector. The measurement techniques commonly used in commercial microscopes, such as RMS to DC converters or lock-in amplifiers often do not provide sufficient bandwidth to perform high speed imaging. On the other hand, many techniques developed especially for high-speed AFM are characterized by poor signal-to-noise ratio. In this paper, a novel amplitude estimation method based on the generalized Goertzel algorithm is presented. The detection system, composed of 16-bit 100 mega-samples per second analog-to-digital converter and field-programmable gate array device, allows to measure the signal amplitude within the time comparable to one oscillation cycle of the AFM cantilever. The effectiveness and validity of the designed detector were investigated by computer simulation. High spatial resolution of the presented method implemented in the actual atomic force microscopy system is also demonstrated.

Experimental Measurement of In-Plane Rolling Nonpneumatic Tire Vibrations Using High-Speed Imaging

2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Imaging ◽  
Correlation Algorithm ◽  
Mode Decomposition ◽  
Series Of Experiments ◽  
Plane Deformations ◽  
Dominant Frequencies

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.

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