An Experimental Study of Mooring Line Damping and Snap Load in Shallow Water

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Wen-Yang Hsu ◽  
Tzu-Ching Chuang ◽  
Ray-Yeng Yang ◽  
Wei-Ting Hsu ◽  
Krish P. Thiagarajan
Keyword(s):  
Shallow Water ◽  
Dynamic Test ◽  
Mooring Line ◽  
Line Geometry ◽  
Static Test ◽  
Image Processing Techniques ◽  
Wave Basin ◽  
Touchdown Point ◽  
A Chain ◽  
Processing Techniques

The aim of this paper is to establish a simple approach to experimentally study the mooring line damping in shallow water, where snap loading may occur more frequently. Experimental measurements were conducted in a wave basin at a scale of 1:50, which corresponds to a full scale of 28 m water depth. A chain made by stainless steel was used, and the tension force at the fairlead was measured by tension gages. Moreover, the line geometry, touchdown point speed, and mooring line velocity were derived from image processing techniques. Surge motions at fairlead were driven from a programmable wavemaker. Regular surge motions with different frequencies and pretensions were tested in this system in order to investigate the quasi-static and dynamic behaviors of the mooring chain. In the quasi-static test, the mooring line keeps a typical catenary shape, and its indicator diagram exhibits a smooth-closed curve. In the dynamic test, the mooring line is fully lifted from the seabed, and it cyclically goes through the stage of semitaut and fully taut. We successfully reproduced a snap event in the laboratory scale, and the resulting mooring line damping can considerably increase in this manner. Two criteria for snap event were examined, and both of them were verified by the experiments.

An Experimental Study of Mooring Line Damping in Shallow Water

2018 ◽  
Author(s):  
Wen-Yang Hsu ◽  
Tzu-Ching Chuang ◽  
Ray-Yeng Yang ◽  
Wei-Ting Hsu ◽  
Krish P. Thiagarajan
Keyword(s):  
Shallow Water ◽  
Dynamic Test ◽  
Processing Technique ◽  
Simple Approach ◽  
Image Processing Technique ◽  
Mooring Line ◽  
Line Geometry ◽  
Static Test ◽  
Wave Basin ◽  
A Chain

The aim of this paper is to establish a simple approach to experimentally study the mooring line damping in shallow water. Experimental measurements were conducted in a wave basin at a scale of 1:50, which corresponds to a full scale of 28 m water depth. A chain made by stainless steel was used and the tension force at the fairlead was measured by tension gauges. Moreover, the mooring line geometry and velocity were computed from image processing technique. Series of horizontal motions at fairlead were driven from a programmable wavemaker. Regular surges with different frequency and pretensions were tested in this system to investigate the quasi-static and dynamic behaviors of the mooring chain. In the quasi-static test, mooring line keeps a typical catenary shape and its indicator diagram exhibits a smooth-closed curve. In the dynamic test, the mooring line is fully lifted from the seabed and it cyclically goes through the stage of semi-taut and fully taut. We successfully reproduced a snap event in the laboratory scale and the resulting mooring line damping can considerably increase in this manner. The mechanism of snap load is investigated by the measured tension, surge and mooring line velocities.

Interaction Between Mooring Line Damping and Response Frequency as a Result of Stiffness Alteration in Surge

2006 ◽  
Author(s):  
Lars Johanning ◽  
George H. Smith ◽  
Julian Wolfram
Keyword(s):  
Limit State ◽  
Extraction Process ◽  
Tidal Range ◽  
Mooring Line ◽  
System Response ◽  
Mooring Lines ◽  
Wave Basin ◽  
A Chain ◽  
Conversion Efficiencies ◽  
Line Design

The design and operation of a chain mooring for a wave energy converter (WEC) is considered. Experimental measurements of a mooring line were conducted in the Heriot-Watt University wave basin at a scale of 1:10. The laboratory procedures were designed to resemble tests undertaken earlier in the year at ‘full’ scale in 24 m water depth. This paper describes and compares these measurements and relates the results to earlier work on mooring lines by Webster [1]. Measurements of both the damping and response frequencies of the mooring are described. Although the present results support partly the conclusions of the earlier work, care must be taken in how these are applied when one is considering mooring line design for WECs. It is concluded that there are significant differences for a WEC for both operational and limit state design in comparison with a more conventional offshore system such as an FPSO or CALM. Although the primary requirement is still one of station-keeping two further considerations may be of great importance. Firstly if a ‘farm’ of devices is to be considered then limitations in sea space may necessitate that the devices be relatively densely packed. This will mean that the ‘footprint’ of the mooring should be constrained, to ensure that the moorings from each device do not interfere with one another and this will have great significance for the loading experienced by the line. This can be exacerbated by variations in tidal range which will have a larger effect in comparison with a conventional deepwater mooring. A second factor may arise if the mooring system response is critical to the WEC energy extraction process. If the mooring becomes part of the ‘tuned’ system then changes in the mooring properties of damping and natural frequency could seriously affect energy conversion efficiencies.

Three-Dimensional Structure of Rotavirus-Fab Complex

1990 ◽  
Vol 48 (1) ◽  
pp. 238-239
Author(s):  
B.V.V. Prasad ◽  
E. Marietta ◽  
J.W. Burns ◽  
M.K. Estes ◽  
W. Chiu
Keyword(s):  
Image Processing ◽  
Smooth Surface ◽  
Three Dimensional ◽  
Outer Shell ◽  
Dimensional Structure ◽  
Structural Studies ◽  
Cell Penetration ◽  
Electron Cryomicroscopy ◽  
Image Processing Techniques ◽  
Processing Techniques

Rotaviruses are spherical, double-shelled particles. They have been identified as a major cause of infantile gastroenteritis worldwide. In our earlier studies we determined the three-dimensional structures of double-and single-shelled simian rotavirus embedded in vitreous ice using electron cryomicroscopy and image processing techniques to a resolution of 40Å. A distinctive feature of the rotavirus structure is the presence of 132 large channels spanning across both the shells at all 5- and 6-coordinated positions of a T=13ℓ icosahedral lattice. The outer shell has 60 spikes emanating from its relatively smooth surface. The inner shell, in contrast, exhibits a bristly surface made of 260 morphological units at all local and strict 3-fold axes (Fig.l).The outer shell of rotavirus is made up of two proteins, VP4 and VP7. VP7, a glycoprotein and a neutralization antigen, is the major component. VP4 has been implicated in several important functions such as cell penetration, hemagglutination, neutralization and virulence. From our earlier studies we had proposed that the spikes correspond to VP4 and the rest of the surface is composed of VP7. Our recent structural studies, using the same techniques, with monoclonal antibodies specific to VP4 have established that surface spikes are made up of VP4.

A Survey on Detection and Classification of Brain Tumor Using Image Processing Techniques

2020 ◽  
pp. 967-973
Author(s):  
V. Deepika ◽  
T. Rajasenbagam
Keyword(s):  
Image Processing ◽  
Brain Tumor ◽  
Soft Tissues ◽  
Tumor Detection ◽  
Tumor Classification ◽  
Normal Brain ◽  
Image Processing Techniques ◽  
Normal Brain Function ◽  
Processing Techniques ◽  
The Brain

A brain tumor is an uncontrolled growth of abnormal brain tissue that can interfere with normal brain function. Although various methods have been developed for brain tumor classification, tumor detection and multiclass classification remain challenging due to the complex characteristics of the brain tumor. Brain tumor detection and classification are one of the most challenging and time-consuming tasks in the processing of medical images. MRI (Magnetic Resonance Imaging) is a visual imaging technique, which provides a information about the soft tissues of the human body, which helps identify the brain tumor. Proper diagnosis can prevent a patient's health to some extent. This paper presents a review of various detection and classification methods for brain tumor classification using image processing techniques.

Rice Panicle Blast Detection and Grading Based on Image Processing Techniques

2019 ◽  
Vol 7 (5) ◽  
pp. 165-168 ◽  
Author(s):  
Prabira Kumar Sethy ◽  
Swaraj Kumar Sahu ◽  
Nalini Kanta Barpanda ◽  
Amiya Kumar Rath
Keyword(s):  
Image Processing ◽  
Image Processing Techniques ◽  
Panicle Blast ◽  
Processing Techniques

Identification of Cucumber Leaf Disease using Image Processing Techniques

2018 ◽  
Vol 6 (6) ◽  
pp. 1493-1499
Author(s):  
Shrutika.C.Rampure . ◽  
Dr. Vindhya .P. Malagi ◽  
Dr. Ramesh Babu D.R
Keyword(s):  
Image Processing ◽  
Image Processing Techniques ◽  
Leaf Disease ◽  
Processing Techniques

Character Reorganization and Categorization using Hybrid Algorithms by Scanned Documents

2019 ◽  
Vol 8 (6S2) ◽  
pp. 943-948
Keyword(s):  
Research Work ◽  
Hybrid Algorithms ◽  
Research Topic ◽  
Image Processing Techniques ◽  
Digital Books ◽  
Otsu Method ◽  
Challenging Research ◽  
Processing Techniques ◽  
Scanned Documents ◽  
Day By Day

Detection and reorganization of text may save a lot of time while reproducing old books text and its chapters. This is really challenging research topic as different books may have different font types and styles. The digital books and eBooks reading habit is increasing day by day and new documents are producing every day. So in order to boost the process the text reorganization using digital image processing techniques can be used. This research work is using hybrid algorithms and morphological algorithms. For sample we have taken an letter pad where the text and images are separated using algorithms. The another objective of this research is to increase the accuracy of recognized text and produce accurate results. This research worked on two different concepts, first is concept of Pixel-level thresholding processing and another one is Otsu Method thresholding.

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