Solvent structure in particle interactions. Low pressure effects and analytic limits

1980 ◽  
Vol 76 ◽  
pp. 776 ◽  
Author(s):  
Derek Y. C. Chan ◽  
D. John Mitchell ◽  
Barry W. Ninham ◽  
Bernard A. Pailthorpe
Keyword(s):  
Low Pressure ◽  
Pressure Effects ◽  
Particle Interactions ◽  
Solvent Structure

Pressure Effects on the Lifetime of Gas High Density Polyethylene Pipes

2021 ◽  
Author(s):  
Yang Wang ◽  
Hui-qing Lan ◽  
Tao Meng ◽  
Bing Wang ◽  
Du du Guo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Induction Time ◽  
High Density Polyethylene ◽  
Reaction Rate ◽  
Low Pressure ◽  
Gas Pressure ◽  
High Density ◽  
Pressure Effects ◽  
Polyethylene Pipes ◽  
Hdpe Pipes

Abstract The purpose of this study was to propose low gas pressure effects on lifetime of natural gas high density polyethylene (HDPE) pipes by thermal-oxidative aging (TOA). The new method to assess the lifetime of HDPE natural gas pipes is based on gas pressure testing. An approach to monitor oxidative induction time (OIT) has been used to predict lifetime. Natural gas HDPE pipes were used to evaluate the effects of low gas pres-sures on oxidative induction time. In order to emphasize the pressure effects, relatively low temperatures at 45, 55, 65 and 75 °C were utilized for the exposure. The low-pressure conditions were created using air at levels of 0, 0.1, 0.2, 0.3 and 0.4 MPa. The property of high density polyethylene pipes was effectively moni-tored using the low pressure oxidative induction time (OIT) test. The results show that the aging reaction rate of high density polyethylene pipes increased exponentially with temperature and gas pressure according to the Arrhenius equation. Analytical models were developed to predict the aging reaction rate and lifetime of natural gas HDPE pipes.

Effects of Pressure Deposition on Plasma Jet and Coatings Microstructure

1996 ◽  
Author(s):  
T. Valente ◽  
L. Bertamini ◽  
M. Tului
Keyword(s):  
Particle Velocity ◽  
Thermal Spraying ◽  
Plasma Jet ◽  
Low Pressure ◽  
Pressure Effects ◽  
Average Particle ◽  
Preliminary Evaluation ◽  
Jet Length ◽  
Visible Part ◽  
Steel Substrates

Abstract Pressure inside the spray chamber plays a key role during coatings manufacturing by thermal spraying and coating properties can be strongly affected by the selected pressure value. Spraying at low pressure results in a longer plasma jet length, higher particle velocity, lower coating porosity and higher purity and phase stability. For what concerns plasma-particle interactions, a reduction of pressure value drastically decreases heat transfer towards particles, therefore high power plasma equipment must be used to achieve a suitable melting degree of sprayed powders. Effects of low pressure values are well known, but few investigation have been carried out on effects of pressure for values higher than 1,000 mbar. In this paper a preliminary evaluation of pressure effects on plasma jet modifications, particle velocity and coatings microstructure is presented. By using the very innovative CAPS (Controlled Atmosphere Plasma Spraying) system, Ni-20%Al powders were sprayed at different pressure values, up to 3,600 mbar. The length and width of the visible part of the plasma jet was measured and controlled. Average particle velocity was also evaluated as a function of pressure. Coatings, manufactured on stainless steel substrates, were characterized by means of scanning electron microscopy and energy dispersive spectroscopy, x-ray diffraction and Vickers microhardness measurements. Results indicate that the higher the spraying pressure the lower the plasma jet length and particle velocity; but also a lower selective evaporation of aluminum and higher microhardness values were observed.

Low Pressure Effects in SEN-Stopper Region in Continuous Casting

2014 ◽  
Vol 86 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Maria Thumfart ◽  
Mirko Javurek
Keyword(s):  
Continuous Casting ◽  
Low Pressure ◽  
Pressure Effects

Numerical Modeling of an Impinging Dusted Plasma Jet Controlled by a Magnetic Field in a Low Pressure

1998 ◽  
Author(s):  
H. Nishiyama ◽  
M. Kuzuhara ◽  
O.P. Solonenko ◽  
S. Kamiyama
Keyword(s):  
Electromagnetic Field ◽  
Radio Frequency ◽  
Particle Velocity ◽  
Particle Trajectory ◽  
Particle Temperature ◽  
Plasma Jet ◽  
Low Pressure ◽  
Particle Interactions ◽  
Low Pressure Plasma Spraying ◽  
Plasma Spraying Process

Abstract The present study is conducted to clarify the magnetic control characteristics of a particle-laden plasma jet impinging on a substrate for the improvement of a low pressure plasma spraying process and its controllable optimization. The plasma jet is described by Eulerian approach and each injected particle is described by Lagrangian approach respectively taking into account the compressible effect, variable transport properties and plasma-particle interactions, coupled with the Maxwell's equations. The effects of the location of the applied radio-frequency electromagnetic field, and of the injected particle size on the particle trajectory, particle velocity and its phase change are clarified by numerical simulation. It is concluded that the particle trajectory is influenced effectively and the injected particle temperature can be controlled strongly by applying the radio-frequency electromagnetic field to the nozzle. The reasonable agreement of particle velocity between calculation and experiment is observed.

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