On-Line Control of Particle Spray Jet and Residual Stresses in Plasma Sprays

Author(s):  
T. Renault ◽  
M. Vardelle ◽  
A. Grimaud ◽  
P. Fauchais ◽  
H. Hoffman

Abstract The quality of plasma sprayed coatings depends strongly on substrate surface preparation, especially roughness, grit residue, and oxidation stage; particle spray jet position and size relative to the plasma jet; impacting particle distribution; particle velocity, temperature, and size prior to impact; substrate temperature; and pass thickness. A simple and low-cost spray and deposit control system developed in our laboratory allows to monitor on-line the position, shape, and centroid of the hot particle spray jet. Such a tool has proved to be very sensitive to any drift in powder injection conditions and torch input parameters. Although it gives no direct information on particle velocity and temperature, this system can be easily implemented in an industrial environment and help to maintain constant the particle parameters during spraying. A CCD camera is used in conjunction with a pyrometer making it possible to measure simultaneously substrate temperature. The system can monitor coating parameters such as deposition efficiency and residual stresses. This paper describes how the system can be used to set the tolerance range of process input parameters to obtain coating parameters within given specifications.

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 104 ◽  
Author(s):  
Felicia Wieland ◽  
Richard Bruch ◽  
Michael Bergmann ◽  
Stefan Partel ◽  
Gerald A. Urban ◽  
...  

Over the last years, polymers have gained great attention as substrate material, because of the possibility to produce low-cost sensors in a high-throughput manner or for rapid prototyping and the wide variety of polymeric materials available with different features (like transparency, flexibility, stretchability, etc.). For almost all biosensing applications, the interaction between biomolecules (for example, antibodies, proteins or enzymes) and the employed substrate surface is highly important. In order to realize an effective biomolecule immobilization on polymers, different surface activation techniques, including chemical and physical methods, exist. Among them, plasma treatment offers an easy, fast and effective activation of the surfaces by micro/nanotexturing and generating functional groups (including carboxylic acids, amines, esters, aldehydes or hydroxyl groups). Hence, here we present a systematic and comprehensive plasma activation study of various polymeric surfaces by optimizing different parameters, including power, time, substrate temperature and gas composition. Thereby, the highest immobilization efficiency along with a homogenous biomolecule distribution is achieved with a 5-min plasma treatment under a gas composition of 50% oxygen and nitrogen, at a power of 1000 W and a substrate temperature of 80 °C. These results are also confirmed by different surface characterization methods, including SEM, XPS and contact angle measurements.


2014 ◽  
Vol 1006-1007 ◽  
pp. 743-746
Author(s):  
Jian Dong Li ◽  
Yu Lan Wei ◽  
Ying Ying Fan

Aiming at the phenomenon that the production line of the strip steel’s detection is fast speed and detection quantity of data is large, which are difficult for worker to detect on line, we put forward a detecting system on defect area of the strip steel’s surface. Using CCD camera regularly to collect the images of the strip steel’s surface and to reflect it back to the detecting device on defect of the strip steel’s surface, and adopting specific arithmetic to analyze and handle images, what can accurately sound a warning while it detects the defected image. It is convenient for worker to take corresponding measures right away. This system has simple structure, low cost, and high defect detection rate, which has the great promotional value.


1997 ◽  
Vol 485 ◽  
Author(s):  
H. Kawanami ◽  
K. Baskar ◽  
I. Sakata ◽  
T. Sekigawa

AbstractThe preliminary results of the effects of the Si beam irradiation for the Si surface preparation on the growth of GaAs on Si by MBE are reported. The effects are combined with thermal cyclic anneal (TCA). A slight improvement in the crystalline quality is observed on the photoluminescence spectra of the films grown with Si irradiation. In our experimental conditions, Si irradiation during the Si surface preparation has not indicated large effects on the FWHM of XRD. It is also indicated that initial substrate surface treatment affects the quality of thicker film through TCA treatment. Higher substrate temperature during Si beam irradiation is expected to indicate positive Si beam irradiation effects.


Author(s):  
F. Hosokawa ◽  
Y. Kondo ◽  
T. Honda ◽  
Y. Ishida ◽  
M. Kersker

High-resolution transmission electron microscopy must attain utmost accuracy in the alignment of incident beam direction and in astigmatism correction, and that, in the shortest possible time. As a method to eliminate this troublesome work, an automatic alignment system using the Slow-Scan CCD camera has been introduced recently. In this method, diffractograms of amorphous images are calculated and analyzed to detect misalignment and astigmatism automatically. In the present study, we also examined diffractogram analysis using a personal computer and digitized TV images, and found that TV images provided enough quality for the on-line alignment procedure of high-resolution work in TEM. Fig. 1 shows a block diagram of our system. The averaged image is digitized by a TV board and is transported to a computer memory, then a diffractogram is calculated using an FFT board, and the feedback parameters which are determined by diffractogram analysis are sent to the microscope(JEM- 2010) through the RS232C interface. The on-line correction system has the following three modes.


2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.


2011 ◽  
Vol 1335 ◽  
Author(s):  
Qiong Wu ◽  
Juanyuan Hao ◽  
Shoulei Shi ◽  
Weifeng Wang ◽  
Nan Lu

ABSTRACTWe report a low-cost and high-throughput method to fabricate large-area light emitting pattern via thermal evaporation of organic molecules on the patterned self-assembled monolayer of homogenous 3-aminopropyltrimethoxysilane. This method is based on the selective deposition of the organic light emitting molecules on the template of self-assembled monolayer (SAM), which is patterned with nanoimprinting lithography. The selectivity can be controlled by adjusting the design of the pattern, the storage duration and the substrate temperature. The deposition selectivity of the molecules may be caused by the different binding energy of the molecules with the SAM and the substrate surface.


2013 ◽  
Vol 834-836 ◽  
pp. 930-934
Author(s):  
Shou Liang Yang ◽  
Bao Liang Yang

The paper proposes a new design of high-accuracy On-line Metal Thickness Measuring Instrument, which was based on EP2C20 series FPGA chip, through adding NiosII soft processor and other interfaces to FPGA, equipped with high precision data collection system and TFT LCD module and so on. The key hardware blocks schematics and components of the RC Oscillation Circuit,eddy current sensor Circuit,rectifier and filter Circuit,A/D converting circuit,FPGA Circuit are described,software flow charts and sample codes are given. According to practice, The measurement range of this system is 1~100 mm and the resolving power is 0.1 μm. degree of linearity is 1%, The system has many features including small volume of hardware, low cost, high detecting precision, convenient operating, high intelligent and so on, leading to broad and bright future. Key words: NiosII processor; eddy current sensor; metal thickness


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