[Variation in the absolute density of water—pure water and seawater—as a function of isotopic composition and dissolved gas content]

1979 ◽  
Vol 26 (12) ◽  
pp. 761
Metrologia ◽  
1995 ◽  
Vol 32 (5) ◽  
pp. 333-362 ◽  
Author(s):  
R Masui ◽  
K Fujii ◽  
M Takenaka

2020 ◽  
Vol 10 (13) ◽  
pp. 4440 ◽  
Author(s):  
Yongxin Liu ◽  
Bin Song ◽  
Linong Wang ◽  
Jiachen Gao ◽  
Rihong Xu

The transformers work in a complex environment, which makes them prone to failure. Dissolved gas analysis (DGA) is one of the most important methods for oil-immersed transformers’ internal insulation fault diagnosis. In view of the high correlation of the same fault data of transformers, this paper proposes a new method for transformers’ fault diagnosis based on correlation coefficient density clustering, which uses density clustering to extrapolate the correlation coefficient of DGA data. Firstly, we calculated the correlation coefficient of dissolved gas content in the fault transformers oil and enlarged the correlation of the same fault category by introducing the amplification coefficient, and finally we used the density clustering method to cluster diagnosis. The experimental results show that the accuracy of clustering is improved by 32.7% compared with the direct clustering judgment without using correlation coefficient, which can effectively cluster different types of transformers fault modes. This method provides a new idea for transformers fault identification, and has practical application value.


Author(s):  
Haruki Daido ◽  
Satoshi Watanabe ◽  
Shin-ichi Tsuda

In the present study, the effects of dissolved gas content on the unsteady cavitating flow around a Clark Y-11.7% hydrofoil are investigated in a cavitation tunnel. Lift and drag forces in various cavitating conditions are directly measured by strain gauges attached on the cantilever supporting the hydrofoil. In addition, the cavitating flow is filmed from the top and the side simultaneously using two high speed video cameras. The high (roughly 6–8ppm) and low (1–2ppm) DO conditions are examined to obtain the qualitative tendencies of the effects of dissolved gas on unsteady cavitation behavior and lift/drag characteristics. It is found that that the relationship between the cavitation behavior and the lift/drag fluctuations does not qualitatively differ in the two different DO conditions, while the amplitude is slightly larger in the low DO condition. At transitional cavity oscillation, in the both DO conditions, the lift/drag coefficients increase during the growth stage of sheet/bubble cavities on the hydrofoil and they decrease when the developed super-cavity disappears. Moreover, it seems that the amplitude of the lift/drag forces in the low DO condition is larger than in the high DO condition but the frequency of lift force fluctuation is not very different.


1960 ◽  
Vol 15 (7) ◽  
pp. 600-612 ◽  
Author(s):  
J. Zähringer ◽  
W. Gentner

In the two chondrites Kapoeta and Abee outstanding rare gas content have been found. From the amount and isotopic composition it is concluded that primordial rare gases have been included in these meteorites. Kapoeta contains all rare gases in excess, while Abee has mainly the heavier rare gases as primordial component. The Ne20/Ne22—and A36/A38—ratios show large deviations from atmospheric Neon and Argon. No such large deviations could be found for Krypton and Xenon.


1987 ◽  
Vol 32 (1) ◽  
pp. 12329J ◽  
Author(s):  
David Kahane ◽  
John I. Thornton

Author(s):  
P Naylor ◽  
A Millward

A technique has been developed which allows the effect on the cavitation inception number of the gas content in the water to be predicted in cavitation experiments. The predicted results have been compared with data obtained during experiments to measure cavitation inception in the tip vortex of a low aspect ratio hydrofoil and have shown good agreement. The results showed that the gas content affected the cavitation inception number significantly at low free stream speeds, particularly below about 4 m/s.


2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Sankar Chakma ◽  
Vijayanand S. Moholkar

This paper presents the effects of various parameters that significantly affect the cavitation. In this study, three types of liquid mediums with different physicochemical properties were considered as the cavitation medium. The effects of various operating parameters such as temperature, pressure, initial bubble radius, dissolved gas content and so forth, were investigated in detail. The simulation results of cavitation bubble dynamics model showed a very interesting link among these parameters for production of oxidizing species. The formation of •OH radical and H2O2 is considered as the results of main effects of sonochemical process. Simulation results of radial motion of cavitation bubble dynamics revealed that bubble with small initial radius gives higher sonochemical effects. This is due to the bubble with small radius can undergo many acoustic cycles before reaching its critical radius when it collapses and produces higher temperature and pressure inside the bubble. On the other hand, due to the low surface tension and high vapor pressure, organic solvents are not suitable for sonochemical reactions.


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