Effect of shielding gas temperature on the welding fume particle formation: Theoretical model

2018 ◽  
Vol 124 ◽  
pp. 112-121 ◽  
Author(s):  
V.I. Vishnyakov ◽  
S.A. Kiro ◽  
M.V. Oprya ◽  
A.A. Ennan
Keyword(s):  
Theoretical Model ◽  
Particle Formation ◽  
Welding Fume ◽  
Shielding Gas ◽  
Gas Temperature

scholarly journals Formation of Particles in Welding Fume Plasmas: Numerical Modeling and Experiment

2019 ◽  
Vol 64 (5) ◽  
pp. 392
Author(s):  
V. I. Vishnyakov ◽  
S. A. Kiro ◽  
M. V. Oprya ◽  
O. D. Chursina ◽  
A. A. Ennan
Keyword(s):  
Numerical Modeling ◽  
Gas Metal Arc Welding ◽  
Welding Fume ◽  
Liquid Droplets ◽  
Breathing Zone ◽  
Shielding Gas ◽  
Gas Temperature ◽  
Gas Plasma ◽  
Metal Arc Welding ◽  
Primary Particles

Formation of particles in a fume plasma obtained from the gas metal arc welding is investigated by the numerical modeling of the plasma evolution. The model of welding fume plasma evolution includes the following processes: vapor emission from the arc zone and mixing with a shielding gas, plasma formation, nucleation, nucleus growth via the material condensation and coalescence, solidification of liquid droplets into primary particles, and coagulation of primary particles into inhalable particles in the breathing zone. The computed results are compared with experimental data on the specific surface area, chemical composition, and dependence of the particle sizes on the shielding gas temperature.

A Model for Calculating the Outlet Flue Gas Temperature of FGD Absorption Tower

2011 ◽  
Vol 130-134 ◽  
pp. 3812-3816
Author(s):  
Gang Xu ◽  
Yao Tian ◽  
Xing Yuan ◽  
Yong Ping Yang
Keyword(s):  
Theoretical Model ◽  
Energy Balance ◽  
Water Consumption ◽  
Flue Gas ◽  
Flue Gas Desulfurization ◽  
Gas Temperature ◽  
Significance Analysis

Theoretical model for calculating the outlet flue gas temperature of limestone-gypsum wet flue gas desulfurization (FGD) absorption tower is important for water consumption calculation. In this paper, the energy balance in the spray zone is analyzed and a model for calculating the outlet flue gas temperature of FGD absorption tower is proposed. An example computation of the outlet flue gas temperature of a typical 600MW class unit’s operation data is introduced, the result has verified the model. A further study of significance analysis has then been made to analyze and simplify the model.

Environmental Criteria for Shielding Gas Selection during Arc Welding of Stainless Steels

2016 ◽  
Vol 246 ◽  
pp. 275-278
Author(s):  
Jolanta Matusiak ◽  
Joanna Wyciślik ◽  
Andrzej Wyciślik
Keyword(s):  
Chemical Composition ◽  
Stainless Steels ◽  
Arc Welding ◽  
Gas Shielded Arc Welding ◽  
Welding Fume ◽  
Emission Rates ◽  
Shielding Gas ◽  
Chromium Vi ◽  
Environmental Criteria ◽  
Carcinogenic Substances

Gas-shielded arc welding of stainless steels belongs to processes which are characterized by the highest concentration of chromium (VI) and nickel in welding fume. These substances are carcinogenic to humans. Material and technological conditions of gas-shielded arc welding of stainless steels influence fume emission rates and chemical composition of welding fume. This fact creates the possibility of process optimization in aspect of emission rates and chemical composition of welding fume including carcinogenic compounds. This paper presents the correlation between shielding gas compositions and fume emission rates and carcinogenic substances contents during gas-shielded arc welding of stainless steels using MIG/MAG, Cold Arc and CMT methods.

Alternatives for Joining Stainless Steel to Reduce Cr(VI) Emissions and Occupational Exposures

2011 ◽  
Vol 27 (02) ◽  
pp. 91-97
Author(s):  
K. M. Paulson ◽  
J. Wang ◽  
N. Topham ◽  
C. Y. Wu ◽  
B. T. Alexandrov ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Stainless Steel ◽  
Air Pollutants ◽  
Occupational Exposures ◽  
Welding Fume ◽  
Oxygen Species ◽  
Hazardous Air Pollutants ◽  
Shielding Gas ◽  
Welding Consumables ◽  
Welding Stainless Steel

Welding stainless steel generates hazardous air pollutants (HAPs). Two technologies were developed to reduce these HAPs. The first, tetramethylsilane is added to the welding shielding gas, and welding proceeds as normal. Reactive oxygen species are consumed, and the resulting metal fume particles are encapsulated. In the second technique, new chromium-free welding consumables are introduced nearly eliminating Cr(VI) in the welding fume.

Nonequilibrium ionization of welding fume plasmas; Effect of potassium additional agent on the particle formation

2017 ◽  
Vol 113 ◽  
pp. 178-188 ◽  
Author(s):  
V.I. Vishnyakov ◽  
S.A. Kiro ◽  
M.V. Oprya ◽  
O.I. Shvets ◽  
A.A. Ennan
Keyword(s):  
Particle Formation ◽  
Welding Fume ◽  
Nonequilibrium Ionization ◽  
Additional Agent

scholarly journals Effect of alkaline additional agent in shielding gas on disperse composition of welding fume

2018 ◽  
Vol 0 (55) ◽  
pp. 126-138
Author(s):  
В. І. Вишняков ◽  
М. В. Опря ◽  
А. А.-А. Еннан
Keyword(s):  
Welding Fume ◽  
Shielding Gas ◽  
Disperse Composition ◽  
Additional Agent

A Model for Analyzing Suicide Prevention

Crisis ◽  
2000 ◽  
Vol 21 (2) ◽  
pp. 80-89 ◽  
Author(s):  
Maila Upanne
Keyword(s):  
Risk Factors ◽  
Theoretical Model ◽  
Protective Factors ◽  
Suicide Prevention ◽  
Suicide Risk ◽  
Practical Work ◽  
Individual Risk ◽  
Self Assessment ◽  
Prevention Project ◽  
Individual Risk Factors

This study monitored the evolution of psychologists' (n = 31) conceptions of suicide prevention over the 9-year course of the National Suicide Prevention Project in Finland and assessed the feasibility of the theoretical model for analyzing suicide prevention developed in earlier studies [ Upanne, 1999a , b ]. The study was formulated as a retrospective self-assessment where participants compared their earlier descriptions of suicide prevention with their current views. The changes in conceptions were analyzed and interpreted using both the model and the explanations given by the subjects themselves. The analysis proved the model to be a useful framework for revealing the essential features of prevention. The results showed that the freely-formulated ideas on prevention were more comprehensive than those evolved in practical work. Compared to the earlier findings, the conceptions among the group had shifted toward emphasizing a curative approach and the significance of individual risk factors. In particular, greater priority was focused on the acute suicide risk phase as a preventive target. Nonetheless, the overall structure of prevention ideology remained comprehensive and multifactorial, stressing multistage influencing. Promotive aims (protective factors) also remained part of the prevention paradigm. Practical working experiences enhanced the psychologists' sense of the difficulties of suicide prevention as well as their criticism and feeling of powerlessness.

Chemical composition of aerosol during particle formation events in boreal forest

Tellus B ◽  
2001 ◽  
Vol 53 (4) ◽  
pp. 380-393 ◽  
Author(s):  
J. M. MÄKELÄ ◽  
S. YLI‐KOIVISTO ◽  
V. HILTUNEN ◽  
W. SEIDL ◽  
E. SWIETLICKI ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Boreal Forest ◽  
Particle Formation
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