Probe effects on concentration profiles in the diffusion layer: Computational modeling and near-surface pH measurements using microelectrodes

2018 ◽  
Vol 292 ◽  
pp. 511-521 ◽  
Author(s):  
Renan A.J. Critelli ◽  
Mauro Bertotti ◽  
Roberto M. Torresi
Keyword(s):  
Computational Modeling ◽  
Diffusion Layer ◽  
Concentration Profiles ◽  
Ph Measurements ◽  
Near Surface ◽  
Surface Ph

Near surface pH measurements in aqueous CO2 corrosion

2018 ◽  
Vol 290 ◽  
pp. 605-615 ◽  
Author(s):  
Rehan De Motte ◽  
Rémy Mingant ◽  
Jean Kittel ◽  
Francois Ropital ◽  
Pierre Combrade ◽  
...  
Keyword(s):  
Co2 Corrosion ◽  
Ph Measurements ◽  
Near Surface ◽  
Surface Ph

Mapping concentration profiles within the diffusion layer of an electrode

2000 ◽  
Vol 2 (5) ◽  
pp. 353-358 ◽  
Author(s):  
Christian Amatore ◽  
Sabine Szunerits ◽  
Laurent Thouin ◽  
Jean-Stephane Warkocz
Keyword(s):  
Diffusion Layer ◽  
Concentration Profiles

Investigation of the Hydrogen Transport Processes in Crystalline Silicon of n-Type Conductivity

2007 ◽  
Vol 131-133 ◽  
pp. 425-430 ◽  
Author(s):  
Anis M. Saad ◽  
Oleg Velichko ◽  
Yu P. Shaman ◽  
Adam Barcz ◽  
Andrzej Misiuk ◽  
...  
Keyword(s):  
Hydrogen Concentration ◽  
Room Temperature ◽  
Crystalline Silicon ◽  
Transport Processes ◽  
Concentration Profiles ◽  
Hydrogen Transport ◽  
Hydrogen Atoms ◽  
Near Surface ◽  
Type Conductivity ◽  
Hydrogen Molecules

The silicon substrates were hydrogenated at approximately room temperature and hydrogen concentration profiles vs. depth have been measured by SIMS. Czochralski grown (CZ) wafers, both n- and p-type conductivity, were used in the experiments under consideration. For analysis of hydrogen transport processes and quasichemical reactions the model of hydrogen atoms diffusion and quasichemical reactions is proposed and the set of equations is obtained. The developed model takes into account the formation of bound hydrogen in the near surface region, hydrogen transport as a result of diffusion of hydrogen molecules 2 H , diffusion of metastable complexes * 2 H and diffusion of nonequilibrium hydrogen atoms. Interaction of 2 H with oxygen atoms and formation of immobile complexes “oxygen atom - hydrogen molecule” (O - H2 ) is also taken into account to explain the hydrogen concentration profiles in the substrates of n-type conductivity. The computer simulation based on the proposed equations has shown a good agreement of the calculated hydrogen profiles with the experimental data and has allowed receiving a value of the hydrogen molecules diffusivity at room temperature.

Determination of oxygen transfer rate to a rotating biological contactor by microelectrode measurement

1994 ◽  
Vol 29 (10-11) ◽  
pp. 471-477 ◽  
Author(s):  
K. Nishidome ◽  
T. Kusuda ◽  
Y. Watanabe ◽  
M. Yamauchi ◽  
M. Mihara
Keyword(s):  
Diffusion Layer ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Oxygen Transfer Rate ◽  
Water Film ◽  
Ammonia Nitrogen ◽  
Concentration Profiles ◽  
Rotating Biological Contactor ◽  
Transfer Rates ◽  
Do Concentration

With an oxygen microelectrode developed by the authors for the measurement of dissolved oxygen (DO) concentration profiles of biofilms in a rotating biological contactor (RBC), DO concentration profiles in the inside and outside of rotating biofilms were measured continuously in the air and water phases. Thicknesses of attached-water film (Lw) and the diffusion layer (Ld) formed on the biofilms were estimated from DO concentration profiles. The oxygen transfer rate to the biofilm was determined with measured DO concentration profiles and a steady state biofilm kinetic model by use of the thicknesses of attached-water film and the diffusion layer. The oxygen transfer rates obtained by two independent methods agreed well, so that the method of the measurement of DO concentration profilesis considered highly reliable. The conclusions in this study are summarized as follows: (1) Lw and Ld on a biofilm attached on a partially submerged rotating biological contactor were 50 and 70 μm thick, respectively; (2) The measured oxygen fluxes were about 10 g-O2/m2/day, and reasonably agreed with those calculated from removing rates of ammonia nitrogen.

Near-surface solution pH measurements during the pitting corrosion of AISI 1020 steel using a ring-shaped sensor

2016 ◽  
Vol 780 ◽  
pp. 379-385 ◽  
Author(s):  
Marina Medina da Silva ◽  
Lucia Helena Mascaro ◽  
Ernesto Chaves Pereira ◽  
Alexsandro Mendes Zimer
Keyword(s):  
Pitting Corrosion ◽  
Solution Ph ◽  
Ph Measurements ◽  
Near Surface
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