Paper physics: Determination of local strains and breaking behaviour of wet paper using a high-speed camera

2011 ◽  
Vol 26 (3) ◽  
pp. 288-296 ◽  
Author(s):  
Timo Lappalainen ◽  
Jarmo Kouko
Keyword(s):  
High Speed ◽  
High Speed Camera ◽  
Local Strains

scholarly journals Crack Propagation Velocity Determination by High-speed Camera Image Sequence Processing

2020 ◽  
Author(s):  
Frank Liebold ◽  
Ali A. Heravi ◽  
Oliver Mosig ◽  
Manfred Curbach ◽  
Viktor Mechtcherine ◽  
...  
Keyword(s):  
Crack Propagation ◽  
High Speed ◽  
Vector Fields ◽  
Displacement Vector ◽  
Image Sequence ◽  
High Speed Camera ◽  
Sequence Processing ◽  
Image Sequence Processing ◽  
Propagation Velocities

The determination of crack propagation velocities can provide valuable information for a better understanding of damage processes of concrete. The spatio-temporal analysis of crack patterns developing at a speed of several hundred meters per second is a rather challenging task. In the paper, a photogrammetric procedure for the determination of crack propagation velocities in concrete specimens using high-speed camera image sequences is presented. A cascaded image sequence processing which starts with the computation of displacement vector fields for a dense pattern of points on the specimen’s surface between consecutive time steps of the image sequence chain has been developed. These surface points are triangulated into a mesh, and as representations of cracks, discontinuities in the displacement vector fields are found by a deformation analysis applied to all triangles of the mesh. Connected components of the deformed triangles are computed using region-growing techniques. Then, the crack tips are determined using principal component analysis. The tips are tracked in the image sequence and the velocities between the time stamps of the images are derived. A major advantage of this method as compared to established techniques is in the fact of its allowing for spatio-temporally resolved, full-field measurements rather than point-wise measurements and that information on crack width can be obtained simultaneously. To validate the experimentation, the authors processed image sequences of tests on four compact-tension specimens performed on a split-Hopkinson tension bar. The images were taken by a high-speed camera at a frame rate of 160,000 images per second. By applying to these datasets the image sequence processing procedure as developed, crack propagation velocities of about 800 m/s were determined with a precision in the order of 50 m/s.

Preliminary studies of the initial segments of the trajectory of a shell shot load fired from a 12 calibre shotgun

2016 ◽  
Vol 292 ◽  
pp. 78-81
Author(s):  
Grzegorz Bogiel ◽  
◽  
Krzysztof Ćwik ◽  
Keyword(s):  
High Speed ◽  
High Speed Camera ◽  
Forensic Examination ◽  
The Creation ◽  
Determination Of Parameters

12 calibre guns and ammunition can be subjected to forensic examination, often there is a need to determine the distance a shot was fired. The article presented a new way to carry out such studies and focused on visualization and the determination of parameters forming a fired, shot cluster. The examination uses a high-speed camera and software for the analysis of the recorded films. As a result of the research dimensions and speed of the creation of a cluster of fired shot were achieved.

Determination of frequencies of oscillations of cloud cavitation on a 2-D hydrofoil from high-speed camera observations

2016 ◽  
Vol 28 (3) ◽  
pp. 369-378 ◽  
Author(s):  
Patrik Zima ◽  
Tomáš Fürst ◽  
Milan SedláŘ ◽  
Martin Komárek ◽  
Rostislav Huzlík
Keyword(s):  
High Speed ◽  
High Speed Camera ◽  
Cloud Cavitation

scholarly journals Crack Propagation Velocity Determination by High-speed Camera Image Sequence Processing

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4415
Author(s):  
Frank Liebold ◽  
Ali A. Heravi ◽  
Oliver Mosig ◽  
Manfred Curbach ◽  
Viktor Mechtcherine ◽  
...  
Keyword(s):  
Crack Propagation ◽  
High Speed ◽  
Vector Fields ◽  
Displacement Vector ◽  
Image Sequence ◽  
High Speed Camera ◽  
Sequence Processing ◽  
Image Sequence Processing ◽  
Propagation Velocities

The determination of crack propagation velocities can provide valuable information for a better understanding of damage processes of concrete. The spatio-temporal analysis of crack patterns developing at a speed of several hundred meters per second is a rather challenging task. In the paper, a photogrammetric procedure for the determination of crack propagation velocities in concrete specimens using high-speed camera image sequences is presented. A cascaded image sequence processing which starts with the computation of displacement vector fields for a dense pattern of points on the specimen’s surface between consecutive time steps of the image sequence chain has been developed. These surface points are triangulated into a mesh, and as representations of cracks, discontinuities in the displacement vector fields are found by a deformation analysis applied to all triangles of the mesh. Connected components of the deformed triangles are computed using region-growing techniques. Then, the crack tips are determined using the principal component analysis. The tips are tracked in the image sequence and the velocities between the time stamps of the images are derived. A major advantage of this method as compared to the established techniques is in the fact that it allows spatio-temporally resolved, full-field measurements rather than point-wise measurements. Furthermore, information on the crack width can be obtained simultaneously. To validate the experimentation, the authors processed image sequences of tests on four compact-tension specimens performed on a split-Hopkinson tension bar. The images were taken by a high-speed camera at a frame rate of 160,000 images per second. By applying the developed image sequence processing procedure to these datasets, crack propagation velocities of about 800 m/s were determined with a precision in the order of 50 m/s.

scholarly journals Optical and Energetic Investigation of an Advanced Corona Ignition System in a Pressure-Based Calorimeter

2020 ◽  
Vol 197 ◽  
pp. 06019
Author(s):  
Valentino Cruccolini ◽  
Gabriele Discepoli ◽  
Federico Ricci ◽  
Carlo Nazareno Grimaldi ◽  
Alessio Di Giuseppe
Keyword(s):  
Thermal Energy ◽  
High Speed ◽  
Operating Conditions ◽  
High Speed Camera ◽  
Ignition System ◽  
Excited Species ◽  
Electrode Voltage ◽  
Correct Determination ◽  
Speed Up

In recent years, radio-frequency corona igniters have been extensively studied for their capability to ensure an effective ignition also in lean or diluted mixtures. Corona ignition is volumetric, with streamers coming from a star-shaped electrode. During the discharge, many radicals and excited species, able to speed up the combustion onset, are generated. At the same time, corona igniters are able to release a considerable amount of thermal energy inside the combustion chamber. The correct determination of such energy is crucial to evaluate the effectiveness of the ignition. In this work, corona discharge is experimentally evaluated inside an optical vessel. In this apparatus, the released thermal energy is measured by means of pressure-based calorimetry, and at the same time the natural luminosity of the streamers is recorded with a high-speed camera. The goal is to find a relationship between thermal energy release and streamers luminosity. Tests are performed using nitrogen as medium, at different pressure levels inside the vessel. The peak electrode voltage is varied to characterize the igniter behaviour in different operating conditions. The results of this work can be used to quantify the corona ignition capabilities to involve a wide amount of medium while releasing a high amount of thermal energy. A repeatability evaluation of streamer evolution is investigated as well.

Real-time shape estimation for continuum robots using vision

Robotica ◽  
2005 ◽  
Vol 23 (5) ◽  
pp. 645-651 ◽  
Author(s):  
M. W. Hannan ◽  
I.D. Walker
Keyword(s):  
Image Processing ◽  
High Speed ◽  
High Speed Camera ◽  
Major Difficulty ◽  
Shape Estimation ◽  
Continuum Robots ◽  
Time Shape ◽  
Continuum Robot ◽  
Shape Determination

This paper describes external camera-based shape estimation for continuum robots. Continuum robots have a continuous backbone made of sections which bend to produce changes of configuration. A major difficulty with continuum robots is the determination of the robot's shape, as there are no discrete joints. This paper presents a method for shape determination based on machine vision. Using an engineered environment and image processing from a high speed camera, shape determination of a continuum robot is achieved. Experimental results showing the effectiveness of the technique on our Elephant's Trunk Manipulator are presented.

Sampling, Preservation and Counting of Samples II: Zooplankton

2017 ◽  
Author(s):  
Peter H. Wiebe ◽  
Ann Bucklin ◽  
Mark Benfield
Keyword(s):  
Genetic Analysis ◽  
High Speed ◽  
Morphological Analysis ◽  
Taxonomic Composition ◽  
Sampling Techniques ◽  
Sample Analysis ◽  
Sample Preservation ◽  
The Past ◽  
Plankton Collection

This chapter reviews traditional and new zooplankton sampling techniques, sample preservation, and sample analysis, and provides the sources where in-depth discussion of these topics is addressed. The net systems that have been developed over the past 100+ years, many of which are still in use today, can be categorized into eight groups: non-opening/closing nets, simple opening/closing nets, high-speed samplers, neuston samplers, planktobenthos plankton nets, closing cod-end samplers, multiple net systems, and moored plankton collection systems. Methods of sample preservation include preservation for sample enumeration and taxonomic morphological analysis, and preservation of samples for genetic analysis. Methods of analysis of zooplankton samples include determination of biomass, taxonomic composition, and size by traditional methods; and genetic analysis of zooplankton samples.

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