Dynamic variation of arc discharge and its effect on corrosion direction under current-carrying sliding

2018 ◽  
Vol 233 (3) ◽  
pp. 380-392 ◽  
Author(s):  
Chaoyong Deng ◽  
Jian Yin ◽  
Hongbo Zhang ◽  
Xiang Xiong ◽  
Pei Wang ◽  
...  
Keyword(s):  
Friction Surface ◽  
High Speed ◽  
Friction And Wear ◽  
Arc Discharge ◽  
Capture Rate ◽  
Three Dimensional ◽  
Discharge Process ◽  
Friction Process ◽  
Large Margin ◽  
Dynamic Variation

Current-carrying sliding tests were performed on an HST-100 high-speed multifunction friction and wear tester. Cf/Cu/C composite was used as the pin, and commercial QCr0.5 was employed as the disk. Sliding tests were carried out at a speed of 30 m/s and a load of 70 N under 25 A, 50 A, 75 A, and 100 A, respectively. Light intensity was collected by a photodiode, and the arc discharge process was recorded by a high-speed camera (HX-5) with a capture rate of 20,000 fp/s. The worn surfaces were characterized by a Nova NanoSEM230 scanning electron microscope and a NANO Focus AG three-dimensional topography instrument. The result indicates that arc discharge occurs randomly, both temporally and spatially, as long as the condition is suitable and occurs more at the beginning and end of the friction process. The arc moves constantly along the friction direction to the outlet. Compared to the inlet, the erosion of the outlet is considerably worse. This finding indicates the arc is moving towards the outlet and grows by a large margin when it leaves the friction surface at the outlet end.

Experimental Study on Gravity Driven Discharging of Quasi-Two-Dimensional Pebble Bed Based on Mathematical Morphology

2020 ◽  
Author(s):  
Yujia Liu ◽  
Sifan Peng ◽  
Nan Gui ◽  
Xingtuan Yang ◽  
Jiyuan Tu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Mathematical Morphology ◽  
High Speed ◽  
Three Dimensional ◽  
Reactor Core ◽  
Engineering Application ◽  
Discharge Process ◽  
Two Dimensional ◽  
Pebble Bed ◽  
Gravity Driven

Abstract The pebbles flow is a fundamental issue for both academic investigation and engineering application in reactor core design and safety analysis. In general, experimental methods including spiral X-ray tomography and refractive index matched scanning technique (RIMS) are applied to obtain the identification of particles’ positions within a three-dimensional pebble bed. However, none of the above methods can perform global bed particles’ position identification in a dynamically discharging pebble bed, and the corresponding experimental equipment is difficult to access due to the complication and high expense. In this research, the experimental study is conducted to observe the gravity driven discharging process in the quasi two-dimensional silos by making use of the high-speed camera and the uniform backlight. A mathematical morphology-based method is applied to the pre-processing of the captured results. After being increased the gray value gradient by the threshold segmentation, the edges of the particles are identified and smoothed by the Sobel algorithm and the morphological opening operation. The particle centroid coordinates are identified according to the Hough circle transformation of the edges. For the whole pebble bed, the self-programmed process has a particle recognition accuracy of more than 99% and a particle centroid position deviation of less than 3%, which can accurately obtain the physical positions of all particles in the entire dynamically discharge process. By analyzing the position evolution of individual particles in consecutive images, velocity field and motion events of particles are observed. The discharging profiles of 5 conditions with different exit are analyzed in this experiment. The results make a contribution to improving the understanding of the mechanism of pebbles flow in nuclear engineering.

Effect of the vibration on friction and wear behavior between the carbon strip and copper contact wire pair

2012 ◽  
Vol 226 (8) ◽  
pp. 722-728 ◽  
Author(s):  
HJ Yang ◽  
GX Chen ◽  
SD Zhang ◽  
WH Zhang
Keyword(s):  
Wear Rate ◽  
Wear Mechanism ◽  
High Speed ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Arc Discharge ◽  
Discharge Energy ◽  
Friction And Wear Behavior ◽  
Contact Wire ◽  
Arc Erosion

This article reports an experimental study on the friction and wear behavior of carbon strip sliding against copper contact wire under strong electric current utilizing a high-speed block-on-ring tester. The dynamic mechanism of electric arc generation was investigated. Scanning electron microscopy was used to observe morphology of worn surfaces of the carbon strips. The results show that arc discharge has a certain correlation with low-frequency vibration of the carbon strip. The arc discharge frequency and the average single arc discharge energy initially decrease and then tend to stable with increasing normal load at different speeds. The wear rate increases first and then decreases and has the minimum when the load is equal to 100 N especially. Moreover, the wear rate steadily increases with increase in arc discharge energy and is almost directly proportional to arc discharge energy. Arc erosion was a dominant wear mechanism occurred in carbon strip sliding against copper contact wire at a low load, accompanying with adhesive wear and material transferring. However, mechanical wear was a main wear mechanism at a high load. Severe arc erosion weakened the conductivity of the carbon strip.

High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

1994 ◽  
Vol 52 ◽  
pp. 218-219
Author(s):  
Robert W. Mackin
Keyword(s):  
Image Analysis ◽  
High Speed ◽  
Three Dimensional ◽  
Image Data ◽  
Ccd Camera ◽  
Objective Lens ◽  
Array Processor ◽  
Vaginal Smears ◽  
Low Contrast ◽  
Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

Effects of Three-Dimensional Pressure Gradients on High-Speed Turbulent Boundary Layers

2021 ◽  
Author(s):  
Scott J. Peltier ◽  
Brian E. Rice ◽  
Ethan Johnson ◽  
Venkateswaran Narayanaswamy ◽  
Marvin E. Sellers
Keyword(s):  
Boundary Layers ◽  
High Speed ◽  
Three Dimensional ◽  
Turbulent Boundary Layers ◽  
Pressure Gradients

Three-Dimensional Imaging through Shock-Waves at Ultra-High Speed.

2018 ◽  
Author(s):  
Yi Chen Mazumdar ◽  
Michael E. Smyser ◽  
Jeffery Dean Heyborne ◽  
Daniel Robert Guildenbecher
Keyword(s):  
Shock Waves ◽  
High Speed ◽  
Three Dimensional ◽  
Three Dimensional Imaging ◽  
Ultra High Speed

scholarly journals High-speed volumetric two-photon fluorescence imaging of neurovascular dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiang Lan Fan ◽  
Jose A. Rivera ◽  
Wei Sun ◽  
John Peterson ◽  
Henry Haeberle ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Speed ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Fluorescence Signal ◽  
Imaging Method ◽  
Spatiotemporal Resolution ◽  
Two Photon

AbstractUnderstanding the structure and function of vasculature in the brain requires us to monitor distributed hemodynamics at high spatial and temporal resolution in three-dimensional (3D) volumes in vivo. Currently, a volumetric vasculature imaging method with sub-capillary spatial resolution and blood flow-resolving speed is lacking. Here, using two-photon laser scanning microscopy (TPLSM) with an axially extended Bessel focus, we capture volumetric hemodynamics in the awake mouse brain at a spatiotemporal resolution sufficient for measuring capillary size and blood flow. With Bessel TPLSM, the fluorescence signal of a vessel becomes proportional to its size, which enables convenient intensity-based analysis of vessel dilation and constriction dynamics in large volumes. We observe entrainment of vasodilation and vasoconstriction with pupil diameter and measure 3D blood flow at 99 volumes/second. Demonstrating high-throughput monitoring of hemodynamics in the awake brain, we expect Bessel TPLSM to make broad impacts on neurovasculature research.

scholarly journals Prevention of Mountain Disasters and Maintenance of Residential Area through Real-Time Terrain Rendering

2021 ◽  
Vol 13 (5) ◽  
pp. 2950
Author(s):  
Su-Kyung Sung ◽  
Eun-Seok Lee ◽  
Byeong-Seok Shin
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
High Speed ◽  
Large Scale ◽  
Civil Engineering ◽  
Three Dimensional ◽  
Sampled Data ◽  
Residential Areas ◽  
Terrain Rendering ◽  
Mountain Disasters

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.

scholarly journals Optical Encryption Based on Computer Generated Holograms in Photopolymer

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1358
Author(s):  
Taihui Wu ◽  
Jianshe Ma ◽  
Chengchen Wang ◽  
Haibei Wang ◽  
Liangcai Cao ◽  
...  
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Angular Spectrum ◽  
Quick Response ◽  
Response Code ◽  
Optical Encryption ◽  
Large Size ◽  
Quick Response Code ◽  
Computer Generated Holograms ◽  
Encryption Method

An optical encryption method based on computer generated holograms printing of photopolymer is presented. Fraunhofer diffraction is performed based on the Gerchberg-Saxton algorithm, and a hologram of the Advanced Encryption Standard encrypted Quick Response code is generated to record the ciphertext. The holograms of the key and the three-dimensional image are generated by the angular spectrum diffraction algorithm. The experimental results show that large-size encrypted Quick Response (QR) code and miniature keys can be printed in photopolymers, which has good application prospects in optical encryption. This method has the advantages of high-density storage, high speed, large fault tolerance, and anti-peeping.

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