Controls for Plasma Spraying Based on Plasma Jet Stability Analysis

1998 ◽  
Author(s):  
L. Beall ◽  
Z. Duan ◽  
J. Schein ◽  
J. Heberlein ◽  
M. Stachowicz ◽  
...  
Keyword(s):  
Process Control ◽  
Plasma Spraying ◽  
High Speed ◽  
Small Degree ◽  
Negative Effects ◽  
Microphone Signal ◽  
Jet Length ◽  
Jet Stability ◽  
Control Scheme ◽  
Coating Characteristics

Abstract Despite the fact that plasma spraying has been a widely used technology over the past three decades, industries using this technology still need higher quality products. Presently, only a small degree of process control is used in most plasma spraying systems. Improved process control should lead to more consistent results and higher quality products. We discuss a relatively simple control scheme consisting of a microphone as a primary sensor and a fuzzy logic look-up model indicating the condition of the anode. Selected frequency peaks in the power spectrum of the microphone signal are analyzed online, and the results are correlated with an average jet length obtained from a series of high speed images. The jet length, in turn, is correlated with coating characteristics. A simple feedback control system is proposed which will counteract the negative effects of an eroded anode on coating quality.

scholarly journals High-Speed Video Analysis of the Process Stability in Plasma Spraying

2021 ◽  
Author(s):  
K. Bobzin ◽  
M. Öte ◽  
M. A. Knoch ◽  
I. Alkhasli ◽  
H. Heinemann
Keyword(s):  
Plasma Spraying ◽  
High Speed ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Time Dependent ◽  
Acquisition Time ◽  
Fast Fourier Transformation ◽  
Frequency Spectra ◽  
Dependent Signal ◽  
The Stability

AbstractIn plasma spraying, instabilities and fluctuations of the plasma jet have a significant influence on the particle in-flight temperatures and velocities, thus affecting the coating properties. This work introduces a new method to analyze the stability of plasma jets using high-speed videography. An approach is presented, which digitally examines the images to determine the size of the plasma jet core. By correlating this jet size with the acquisition time, a time-dependent signal of the plasma jet size is generated. In order to evaluate the stability of the plasma jet, this signal is analyzed by calculating its coefficient of variation cv. The method is validated by measuring the known difference in stability between a single-cathode and a cascaded multi-cathode plasma generator. For this purpose, a design of experiment, covering a variety of parameters, is conducted. To identify the cause of the plasma jet fluctuations, the frequency spectra are obtained and subsequently interpreted by means of the fast Fourier transformation. To quantify the significance of the fluctuations on the particle in-flight properties, a new single numerical parameter is introduced. This parameter is based on the fraction of the time-dependent signal of the plasma jet in the relevant frequency range.

Rule-Based Control of Weld Bead Width in Pulsed Gas Tungsten Arc Welding (GTAW)

1996 ◽  
Vol 210 (1) ◽  
pp. 93-98 ◽  
Author(s):  
C S Wu ◽  
Y C Liu
Keyword(s):  
Process Control ◽  
Arc Welding ◽  
High Speed ◽  
Gas Tungsten Arc Welding ◽  
Weld Bead ◽  
Bead Width ◽  
Rule Based ◽  
Television Camera ◽  
Gas Tungsten Arc ◽  
Gas Tungsten

A rule-based control system of weld bead width is established for realizing in-process control of pulsed gas tungsten arc welding. The system consists of a microprocessor-controlled power supply and working table, a solid state television camera, a high-speed analogue-to-digital converter and an image processing and control computer. Considering the characteristic of arc light and its influence on vision sensing, special measures were taken for image capturing, processing and weld bead width extraction. The rule-based model was combined with the principle of PID (proportional integral derivative) control, and a parameter-changing PID controller was designed. The bead-on-plate welding experiments were carried out. The results show that the system is of good adaptablity for in-process control of weld bead width in pulsed gas tungsten arc welding (GTAW).

High Speed Liquid Chromatography for In‐Process Control

2006 ◽  
Vol 29 (7-8) ◽  
pp. 931-948 ◽  
Author(s):  
Domingo Blanco Gomis ◽  
Noé Sánchez Núñez ◽  
M. Dolores Gutiérrez Álvarez
Keyword(s):  
Liquid Chromatography ◽  
Process Control ◽  
High Speed

scholarly journals Coatings of Carbide-Metal Systems (Cr3C2-NiCr and WC-Co-Cr) Deposited by High-Velocity Atmospheric Plasma Spraying from Specially Modified Fine-Grained Powders

2018 ◽  
Vol 1 (1) ◽  
pp. 18-23
Author(s):  
Vadim Verlotski ◽  
Keyword(s):  
Plasma Spraying ◽  
High Speed ◽  
Plasma Deposition ◽  
Thermal Spraying ◽  
Atmospheric Plasma ◽  
Metal Particles ◽  
Fine Grained ◽  
Plasma Torches ◽  
Carbide Coatings ◽  
Gas Tight

In this article, the author poses and responds to a provocative question that has practically ceased to be asked in the field of thermal spraying of carbide coatings: Is the current worldwide trend of using only unmelted metal particles to form coatings (HVOF, HVAF and cold spray methods) correct, and is the deposition of completely melted powders (plasma spraying methods) really outdated? The results of high-speed plasma deposition of new carbide powders allowed the author to prove that only coatings from molten particles can solve the main problem of such coatings, namely the problem of permeability along the grain boundaries. Through the use of modern Axial III plasma torches combined with optimized fine-grained powders, it has been possible to create Cr3C2-NiCr as well as WC-Co-Cr gas-tight layers.

scholarly journals Infrastructure costs and benefits of European high-speed rail

2021 ◽  
Vol 1 (2) ◽  
pp. 47-53
Author(s):  
Nedžad Branković ◽  
Aida Kalem
Keyword(s):  
High Speed ◽  
New Technologies ◽  
Operational Parameters ◽  
Negative Effects ◽  
Railway Network ◽  
High Speed Rail ◽  
Rail Network ◽  
High Speed Trains ◽  
Conventional Rail ◽  
Ecologically Sustainable

The development of new technologies has significantly influenced railways modernization and has caused the appearance of high-speed rail which represent a safe, comfortable and ecologically sustainable way of transportation. The high-speed rail present a big step in a relation to conventional railways, where the biggest difference is speed which even entails a change of other organizational and operational parameters, better utilization of trains, higher performance of manpower and better service to users.  That is visible in many cities around the world where high-speed trains are used by billions of users. In the EU there is no unique high-speed railway network, besides that in many EU member countries various operational models are applied. The future of the high-speed railways market depends on political, economical and technical factors and challenges as high infrastructure costs, various rates of return on investment and the negative effects of economic crises. The main objective of the paper is to analyze infrastucture costs of high-speed rail in Europe and benefits such us  time savings, higher reliability, comfort, safety, reducing pollution and the release of capacity in the conventional rail network, roads and airport infrastructure.

Properties of tungsten coating deposited onto copper by high-speed atmospheric plasma spraying

2011 ◽  
Vol 414 (1) ◽  
pp. 8-11 ◽  
Author(s):  
Huang Jianjun ◽  
Wang Fan ◽  
Liu Ying ◽  
Jiang Shishou ◽  
Wang Xisheng ◽  
...  
Keyword(s):  
Plasma Spraying ◽  
High Speed ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Tungsten Coating

Investigation of Environmental Effects of High Speed Boats

2020 ◽  
Author(s):  
Ahmet Dursun Alkan ◽  
Onur Usta ◽  
Alpay Acar ◽  
Elis Atasayan
Keyword(s):  
High Speed ◽  
Navier Stokes ◽  
Noise Prediction ◽  
Total Resistance ◽  
Test Results ◽  
Negative Effects ◽  
Towing Tank ◽  
Towing Tank Test ◽  
Tank Test ◽  
Propulsion Power

Luxury high-speed boats are increasingly being used for entertainment purposes. However, not only humans, but also animals are negatively affected by high-speed boats, and time is running out fast for people to do something about it. This study presents a review of current negative effects of high-speed boats to the environment. In this study, the flow around a benchmark planing Fridsma boat is simulated by CFD and resistance values for different non-dimensional Froude number (Fn) conditions are validated from the experimental results obtained from the literature. Using the same CFD methodology, a catamaran model in which the towing tank test results are available, is simulated for different Fn conditions and resistance values are predicted. In the CFD analysis, unsteady flow around the Fridsma hull model and catamaran model is simulated using overset meshing technique and turbulence is modeled by Reynolds Averaged Navier Stokes (RANS) with SST (Menter) k-omega turbulence model. Resistance values are compared with the experimental data and required propulsion powers are estimated for different Fn conditions. Then, total resistance of the catamaran for full-scale vessel is calculated using an extrapolation method and required propulsion power predictions are conducted. Noise prediction, corresponding to the required propulsion power are presented. In particular, the change of noise level and harmful gases released into the environment, when the speed of the vessel increases are examined and discussed. Consequently, it is believed that this study would lay an important foundation for the widespread investigation for the negative effects of the high-speed boats in the future.

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