Surge Propagation Characteristic of Cables Fixed to a Tower

1991 ◽  
Vol 111 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Nozomi Mori ◽  
Toshiyuki Inoue ◽  
Yasuhiro Yamashita ◽  
Toshiroh Yoshida ◽  
Yoshio Maruyama ◽  
...  
Keyword(s):  
Propagation Characteristic

scholarly journals Research on Secure Debugging Interaction of Sensor Nodes Based on Visible Light Communication

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 953 ◽  
Author(s):  
Yuanchu Yin ◽  
Jiefan Qiu ◽  
Zhiqiang Li ◽  
Mingsheng Cao
Keyword(s):  
Visible Light ◽  
Channel Coding ◽  
Sensor Node ◽  
Source Coding ◽  
Visible Light Communication ◽  
Propagation Characteristic ◽  
Transmission Efficiency ◽  
Sensor Nodes ◽  
Pulse Interval ◽  
Inaccessible Area

When a wireless sensor node’s wireless communication fails after being deployed in an inaccessible area, the lost node cannot be repaired through a debugging interaction that relies on that communication. Visible light communication (VLC) as a supplement of radio wave communication can improve the transmission security at the physical layer due to its unidirectional propagation characteristic. Therefore, we implemented a VLC-based hybrid communication debugging system (HCDS) based on VLC using smartphone and sensor node. For the system’s downlink, the smartphone is taken as the VLC gateway and sends the debugging codes to the sensor node by the flashlight. To improve the transmission efficiency of the downlink, we also propose a new coding method for source coding and channel coding, respectively. For the source coding, we analyze the binary instructions and compress the operands using bitmask techniques. The average compression rate of the binary structure reaches 84.11%. For the channel coding, we optimize dual-header pulse interval (DH-PIM) and propose overlapped DH-PIM (ODH-PIM) by introducing a flashlight half-on state. The flashlight half-on state can improve the representation capability of individual symbols. For the uplink of HCDS, we use the onboard LED of the sensor node to transmit feedback debugging information to the smartphone. At the same time, we design a novel encoding format of DH-PIM to optimize uplink transmission. Experimental results show that the optimized uplink transmission time and BER are reduced by 10.71% and 22%, compared with the original DH-PIM.

Characteristic of Interface Crack Propagation in Dissimilar Weld Joints

2014 ◽  
Vol 988 ◽  
pp. 249-252 ◽  
Author(s):  
Wei Bing Wang ◽  
He Xue ◽  
Fu Qiang Yang ◽  
Xu Sheng Zhou
Keyword(s):  
Interface Crack ◽  
Propagation Characteristic ◽  
Extended Finite Element ◽  
Lower Yield ◽  
Mechanical Heterogeneity ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
Propagation Behavior ◽  
Lower Yield Strength ◽  
Ductile Fracture Model

The propagation behavior of crack with different initiation position is affected by the constraint effect differences in dissimilar weld joints mechanical heterogeneity. The ductile fracture model of interface crack in dissimilar weld joints was built by adopting extended finite element method; the propagation characteristic of interface crack was summarized. The results indicate that the strength mismatch of materials at sides of interface will increase trend of crack advancing into the relative soft material which has lower yield strength and lower hardening exponent.

Seismic wave propagation characteristic and its effects on the failure of steep jointed anti-dip rock slope

Landslides ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 105-123 ◽  
Author(s):  
Long-qi Li ◽  
Neng-pan Ju ◽  
Shuai Zhang ◽  
Xiao-xue Deng ◽  
Daichao Sheng
Keyword(s):  
Wave Propagation ◽  
Seismic Wave ◽  
Rock Slope ◽  
Seismic Wave Propagation ◽  
Propagation Characteristic

Propagation Characteristic of Ultrasonic in BT20 Titanium Alloy and Research on Distribution of Ultrasonic Field in Molten Pool of Laser Deposition Repair

2013 ◽  
Vol 40 (12) ◽  
pp. 1203009 ◽  
Author(s):  
杨光 Yang Guang ◽  
郭鹏飞 Guo Pengfei ◽  
王维 Wang Wei ◽  
钦兰云 Qin Lanyun ◽  
卞宏友 Bian Hongyou ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Molten Pool ◽  
Ultrasonic Field ◽  
Propagation Characteristic ◽  
Laser Deposition

Vibration and Wave Propagation Characteristic Analysis of Periodic Auxetic Star-Shaped Structure System

2020 ◽  
Vol 1009 ◽  
pp. 101-106
Author(s):  
Jia Yi Yeh
Keyword(s):  
Wave Propagation ◽  
Expansion Method ◽  
Propagation Characteristic ◽  
Propagation Characteristics ◽  
Plane Wave Expansion ◽  
Plane Wave Expansion Method ◽  
Characteristic Analysis ◽  
Structure System ◽  
Finite Element Software ◽  
3D Printed

In this paper, vibration and wave propagation characteristics of auxetic metamaterial of the star-shaped structure system are studied. The plane wave expansion method is adopted to investigate and calculate the band structures of the auxetic star-shaped structure system. Besides, the frequency ranges of the complete bandgaps are also obtained and discussed. Then, the COMSOL® finite element software is utilized to solve wave propagation characteristics within the periodic auxetic star-shaped honeycomb structures. After that, the auxetic star-shaped structure devices made by 3D printed machine are used to measure the experimental results and also compared with numerical results. It can be seen that good agreements can be found in the discussions.

The Calculation of Stress Intensity Factors and the Analysis of Propagation Characteristic of Crack at Hole

2011 ◽  
Vol 250-253 ◽  
pp. 1856-1861
Author(s):  
Li Jun Lu ◽  
Jian Ping Liu ◽  
Zhong Mei Li
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Propagation Velocity ◽  
Propagation Characteristic ◽  
Propagation Model ◽  
Intensity Factors ◽  
Crack Propagation Velocity ◽  
Guyed Mast ◽  
Shape And Size

This paper focusing on the crack at hole of guyed-mast’s ear-plate connecting cables and shaft of guyed-mast, adopting two degree of freedom crack propagation model, track the crack propagation according to the increment of the deepest point and the surface point on the crack front of crack at hole of guyed-mast’s ear-plate. The stress intensity factors of I,II and III type crack with given shape and size have been calculated via finite element method, and a numerical method of calculating stress intensity factors with any shape and size crack has been proposed; furthermore according to modified I, II and III type compound crack propagation velocity formula on the basis of Paris crack propagation velocity formula, we analyzed the changing of crack shape parameter a/c with crack size parameter a/T of crack at hole of ear-plate connecting cable and shaft of guyed-mast by numerical integration method and obtained the propagation characteristic.

Circumferential Propagation Characteristic of Unsteady Flow in a Subsonic Axial Flow Compressor Rotor at Different Reynolds Numbers

2019 ◽  
Author(s):  
Zhiyang Chen ◽  
Yanhui Wu ◽  
Yanwen Zhang ◽  
Junwen Gan ◽  
Jinhuaiyuan An
Keyword(s):  
Unsteady Flow ◽  
Frequency Band ◽  
Radial Flow ◽  
Propagation Characteristic ◽  
Leakage Flow ◽  
Tip Leakage Flow ◽  
Characteristic Frequencies ◽  
Tip Leakage ◽  
Flow Unsteadiness ◽  
Compressor Rotor

Abstract This paper studies the circumferential propagation characteristic of unsteady flow that occurs close to stall in a subsonic axial compressor rotor at different Reynolds number (Re). Experimental measurements are first conducted at high Re on the ground, and numerical investigations are carried out at two altitudes to explore the mechanism of circumferential propagation characteristic at different Re. The stability operating range of the compressor rotor gets small with the decrease of Re. Rotating instability (RI) is observed in the blade passage near the stall limit of the test rotor at high Re on the ground, which is characterized by a hump frequency band in the spectrum. Characteristic frequencies of numerical pressure signals at fixed frame are limited in the frequency band of RI at high Re. The cross power spectrums of numerical pressure signals detected in the neighboring passages suggest that circumferential disturbances rotates in the flow fields at different Re. Characteristic frequencies of the flow unsteadiness change with the decrease of Re. At high Re, the circumferential propagation of tip leakage flow unsteadiness is controlled by the interaction of the tip leakage flow and incoming flow, which is linked to RI. When the Re is reduced, the tip leakage flow gets weak and the radial flow from the hub to tip induced by the suction surface flow separation is dominant in the tip region. Thereafter, both the tip leakage flow and radial flow are associated with the blade tip loading, which changes the flow mechanism of RI.

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