scholarly journals Research on structure and technological parameters of multi-channel cold spraying nozzle

2021 ◽  
Vol 5 (1(113)) ◽  
pp. 6-14
Author(s):  
Wenjie Hu ◽  
Kun Tan ◽  
Sergii Markovych ◽  
Tingting Cao
Keyword(s):  
High Speed ◽  
Single Channel ◽  
Cold Spraying ◽  
Particle Collision ◽  
Powder Injection ◽  
Material Surface ◽  
Specific Reference ◽  
Technological Parameters ◽  
Internal Channel ◽  
Powder Spraying

Cold spraying technology is a method to obtain coating by the high-speed collision of particles with the substrate through supersonic (300–1200 m/s) propulsion gas. The deposition process is mainly mechanical bonding, which has attracted more and more attention in engineering applications. The critical component of a cold spraying system is the nozzle. The performance of the nozzle directly affects the quality of the material surface coating. Therefore, the discussion of the nozzle is of great significance. At present, there are many examples of cold spraying single-channel nozzles in engineering, but there are few reports about multi-channel cold spraying nozzles. This paper explores and studies the multi-channel cold spraying nozzle, designs a special three internal channel nozzle, and adopts a 90° angle in the divergent section of the nozzle. When spraying in a small area, the nozzle with angle has apparent advantages for spraying more areas. The powder injection pressure, particle size, recovery coefficient, and internal channel position are analyzed, which affect the particle trajectory. Combined with these factors, the multi-channel nozzle is optimized and improved to solve the problem of particle collision with the inner wall of the nozzle. Finally, the technological parameters of aluminum, titanium, copper, nickel, magnesium, and zinc powders are preliminarily studied using the multi-channel nozzle. The results show that the multi-channel nozzle meets the critical velocity requirements of copper, magnesium, and zinc powder spraying in the homogeneous (powder and matrix are the same material) and aluminum powder spraying in the case of heterogeneous (powder and matrix are different materials), the multi-channel nozzle has a sound engineering application prospect and provides a specific reference for relevant technicians.

Tributary Mapping Multiplexing an Efficient Technique for High Speed Fiber Optic Communication

2018 ◽  
Vol 6 (2) ◽  
Author(s):  
Usman Illahi ◽  
Javed Iqbal ◽  
Muhammad Ismail Sulaiman ◽  
Muhammad Alam ◽  
Mazliham Mohd Su'ud
Keyword(s):  
Spectral Efficiency ◽  
High Speed ◽  
Fiber Optic ◽  
Single Channel ◽  
Efficient Technique ◽  
High Dispersion ◽  
Optical Filtering ◽  
Fiber Optic Communication ◽  
Optic Communication ◽  
Dispersion Tolerance

<p>A novel technique of multiplexing called Tributary Mapping Multiplexing (TMM) is<br />applied to a single channel wavelength division multiplexing system and performance is monitored on the basis of simulation results. To elaborate the performance of TMM in this paper, a 4-User TMM system over single wavelength channel is demonstrated. TMM showed significant tolerance against narrow optical filtering as compared to that of conventional TDM at the rate of 40 Gbit/s. The above calculations are made by optical filter bandwidth and dispersion tolerance that was allowed at minimum. The spectral efficiency achieved by this TMM was 1 b/s/Hz and it was executed by using transmitters and receivers of 10 Gbit/s without polarized multiplexing. The high spectral efficiency, high dispersion tolerance and tolerance against strong optical filtering makes TMM an efficient technique for High<br />Speed Fiber Optic Communication.</p>

Numerical Analysis of Influence of Roughness of Material Surface on High-Speed Liquid Droplet Impingement

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Hirotoshi Sasaki ◽  
Yuka Iga
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
Erosion Rate ◽  
Liquid Droplet ◽  
Material Surface ◽  
Liquid Droplets ◽  
Fluid Machinery ◽  
Droplet Impingement ◽  
Surface Liquid ◽  
Droplet Impingement Erosion

This study explains why the deep erosion pits are formed in liquid droplet impingement erosion even though the droplets uniformly impinge on the entire material surface. Liquid droplet impingement erosion occurs in fluid machinery on which droplets impinge at high speed. In the process of erosion, the material surface becomes completely roughened by erosion pits. In addition, most material surface is not completely smooth and has some degree of initial roughness from manufacturing and processing and so on. In this study, to consider the influence of the roughness on the material surface under droplet impingement, a numerical analysis of droplets impinging on the material surface with a single wedge and a single bump was conducted with changing offsets between the droplet impingement centers and the roughness centers on each a wedge bottom and a bump top. As results, two mechanisms are predicted from the present numerical results: the erosion rate accelerates and transitions from the incubation stage to the acceleration stage once roughness occurs on the material surface; the other is that deep erosion pits are formed even in the case of liquid droplets impinging uniformly on the entire material surface.

scholarly journals Thermographic Study of Chip Temperature in High-Speed Dry Milling Magnesium Alloys

2016 ◽  
Vol 7 (2) ◽  
pp. 86-92 ◽  
Author(s):  
Józef Kuczmaszewski ◽  
Ireneusz Zagórski ◽  
Piotr Zgórniak
Keyword(s):  
Temperature Measurement ◽  
Magnesium Alloys ◽  
High Speed ◽  
Machining Process ◽  
Dry Milling ◽  
Technological Parameters ◽  
Chip Temperature ◽  
Thermographic Study ◽  
On Chip ◽  
The Impact

Abstract This paper presents an overview of the state of knowledge on temperature measurement in the cutting area during magnesium alloy milling. Additionally, results of own research on chip temperature measurement during dry milling of magnesium alloys are included. Tested magnesium alloys are frequently used for manufacturing elements applied in the aerospace industry. The impact of technological parameters on the maximum chip temperature during milling is also analysed. This study is relevant due to the risk of chip ignition during the machining process.

Design of a multi-function high-speed digital baseband data acquisition system

2021 ◽  
Vol 21 (10) ◽  
pp. 248
Author(s):  
Xin Pei ◽  
Jian Li ◽  
Na Wang ◽  
Toktonur Ergesh ◽  
Xue-Feng Duan ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Radio Telescope ◽  
High Speed ◽  
Single Channel ◽  
Wide Band ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Single Server ◽  
Long Baseline ◽  
Digital Baseband

Abstract A multi-function digital baseband data acquisition system is designed for the sampling, distribution and recording of wide-band multi-channel astronomical signals. The system hires a SNAP2 board as a digital baseband converter to digitize, channelize and packetize the received signal. It can be configured dynamically from a single channel to eight channels with a maximum bandwidth of 4096 MHz. Eight parallel HASHPIPE instances run on four servers, each carrying two NVMe SSD cards, achieving a total continuous write rate of 8 GB s−1. Data are recorded in the standard VDIF file format. The system is deployed on a 25-meter radio telescope to verify its functionality based on pulsar observations. Our results indicate that during the 30-minute observation period, the system achieved zero data loss at a data recording rate of 1 GB s−1 on a single server. The system will serve as a verification platform for testing the functions of the QTT (QiTai radio Telescope) digital backend system. In addition, it can be used as a baseband/VLBI (Very Long Baseline Interferometry) recorder or D-F-engine of correlator/beamformer as well.

scholarly journals A Study on the Sintering Behavior of T42 High Speed Steel by Powder Injection Molding (PIM) Process

2012 ◽  
Vol 19 (2) ◽  
pp. 117-121 ◽  
Author(s):  
Dong-Wook Park ◽  
Hye-Seong Kim ◽  
Young-Sam Kwon ◽  
Kwon-Koo Cho ◽  
Su-Gun Lim ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Speed ◽  
High Speed Steel ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Sintering Behavior

A High Speed 8B/10B Encoder/Decoder Design Based on Low Cost FPGA

2012 ◽  
Vol 462 ◽  
pp. 361-367 ◽  
Author(s):  
Zhang Jin Chen ◽  
Guo Hai Zhong ◽  
Zhuo Bi
Keyword(s):  
High Speed ◽  
Single Channel ◽  
Low Cost ◽  
Maximum Frequency ◽  
Clock Frequency ◽  
Parallel Pipeline ◽  
Quartus Ii ◽  
Simulation Results ◽  
Decoder Design ◽  
Timing Simulation

A high speed 8B/10B Encoder/Decoder is presented in this paper. The Encoder/Decoder is based on Altera’s low cost FPGA Cyclone family. The Encoder/Decoder includes parallel pipeline structure. The Encoder/Decoder is applied to the Serializer/Deserializer (SERDES) of high-speed serial bus. The Encoder/Decoder is synthesized and simulated by Quartus II 9.1. The synthesis and analysis results show the maximum frequency is more than 359MHz. The timing simulation results show the clock frequency is more than 125 MHz. The single channel data rate of serial bus can get to 1.25Gbps. The proposed Encoder/Decoder can meet the requirements of most high-speed serial bus.

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