scholarly journals THE PROBABILITY CHARACTERISTICS OP WAVES AND WAVE PRESSURES AT A VERTICAL BREAKWATER

1984 ◽  
Vol 1 (19) ◽  
pp. 50
Author(s):  
Huang Peiji ◽  
Zhao Binglai
Keyword(s):  
Probability Distribution ◽  
High Frequency ◽  
Pressure Field ◽  
Spectral Component ◽  
High Frequency Band ◽  
Wave Pressure ◽  
Spectral Components ◽  
Wave Heights ◽  
Vertical Breakwater ◽  
Equilibrium Range

In this paper, under the condition of waves in front of a breakwater being not broken, studies were made on the characterises of probability distribution of waves and wave pressures, the regularity of the spectral component attenuation with depth and the constitution of the high frequency band of wave pressure spectrum. The distributions of wave heights in front of a vertical breakwater, the range of wave pressure fluctuation at different subsurface levels, and the wave periods have shown that they are practically invariable with depth and can be determined theoretically. The spectral constitution of wave pressure field and the regularity of attenuation of spectral components were analyzed at the vertical breakwater, and a new expression describing the equilibrium range of wave pressure spectrum was obtained.

The SIRIO satellite, 1968––1977: Between scientific engagement and managerial inexperience

2004 ◽  
Vol 34 (2) ◽  
pp. 371-398
Author(s):  
LUCIA ORLANDO
Keyword(s):  
International Economic ◽  
Organizational Structure ◽  
Frequency Band ◽  
High Frequency ◽  
Aerospace Industry ◽  
Space Research ◽  
High Frequency Band ◽  
Political Uncertainty ◽  
The 1960S ◽  
Super High Frequency

ABSTRACT: The story of the first Italian communications satellite, SIRIO, started in 1968, after the failure of the European project for the vector ELDO-PAS. The story up to the launch in 1977 involved the encumbering legacy of the San Marco satellite's success in the 1960s, political uncertainty in Italy, international economic crises of the 1970s, an overtly complex management system, and an inexperienced aerospace industry. Despite these handicaps, SIRIO won the race with its nearest competitor, the European satellite OTS, which had a similar research aim in the super high frequency band. In addition to collecting a large amount of useful data, SIRIO catalyzed the process for developing an improved organizational structure for Italian space research.

Application Of Elastic Layers To Register Pressure Field On The Model Surface In Supersonic Flow

2016 ◽  
Vol 11 (1) ◽  
pp. 23-33
Author(s):  
Maxim Golubev ◽  
Andrey Shmakov
Keyword(s):  
Surface Waves ◽  
High Frequency ◽  
High Speed ◽  
Pressure Pulsation ◽  
Pressure Field ◽  
Leading Edge ◽  
Supersonic Wind Tunnel ◽  
Register Pressure ◽  
Elastic Layers ◽  
Sharp Leading Edge

The work presents the results of application of panoramic interferential technique which is based on elastic layers (sensors) usage to obtain pressure distribution on the flat plate having sharp leading edge. Experiments were done in supersonic wind tunnel at Mach number M = 4. Sensitivity and response time are shown to be enough to register pressure pulsation against standing and traveling sensor surface waves. Applying high-frequency image acquiring is demonstrated to make possible to distinguish at visualization images high-speed disturbances propagating in the boundary layer from low-speed surface waves

Nanoelectromagnetic of the N-doped single wall carbon nanotube in the extremely high frequency band

Nanoscale ◽  
2017 ◽  
Vol 9 (37) ◽  
pp. 14192-14200 ◽  
Author(s):  
B. Aïssa ◽  
M. Nedil ◽  
J. Kroeger ◽  
M. I. Hossain ◽  
K. Mahmoud ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Frequency Band ◽  
Electromagnetic Interference ◽  
High Frequency ◽  
High Electrical Conductivity ◽  
High Frequency Band ◽  
High Demand ◽  
Extremely High Frequency ◽  
Minimal Thickness

Materials offering excellent mechanical flexibility, high electrical conductivity and electromagnetic interference (EMI) attenuation with minimal thickness are in high demand, particularly if they can be easily processed into films.

scholarly journals Internal Leakage Predicition of Hydraulic Spool valves Based on Acoustic Emission Technology

2021 ◽  
Vol 2113 (1) ◽  
pp. 012016
Author(s):  
Fei Song ◽  
Likun Peng ◽  
Jia Chen ◽  
Benmeng Wang
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
Peak Frequency ◽  
Leakage Rate ◽  
High Frequency Band ◽  
Signal Characteristics ◽  
Spool Valves ◽  
The Relationship ◽  
Ae Signals ◽  
Acoustic Emission Technology

Abstract In order to realize the nondestructive testing (NDT) of the internal leakage fault of hydraulic spool valves, the internal leakage rate must be predicted by AE (acoustic emission) technology. An AE experimental platform of internal leakage of hydraulic spool valves is built to study the characteristics of AE signals of internal leakage and the relationship between AE signals and leakage rates. The research results show the AE signals present a wideband characteristic. The main frequencies are concentrated in 30~50 kHz and the peak frequency is around 40 kHz. When the leakage rate is large, there are significant signal characteristics appearing in the high frequency band of 75~100 kHz. The exponent of the root mean square(RMS) of AE signals is positively correlated with the exponent of the leakage rate only if the leakage rate is greater than 2~3 mL/min. This find could be used to predict the internal leakage rate of hydraulic spool valves.

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