Distribution of aldehydes compared to other oxidation parameters in oil matrices during autoxidation

2021 ◽  
Author(s):  
KeunCheol Yoo ◽  
JaeHwan Lee ◽  
ChanHyung Kim ◽  
JiHee Hong ◽  
SoYoon Park ◽  
...  
Keyword(s):  
Oxidation Parameters

scholarly journals Nanotubular Oxide Layer Formed on Helix Surfaces of Dental Screw Implants

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 115 ◽  
Author(s):  
Magdalena Jażdżewska ◽  
Michał Bartmański
Keyword(s):  
Oxide Layer ◽  
Cross Sections ◽  
Surface Coverage ◽  
Artificial Saliva ◽  
Corrosion Current ◽  
Optical Microscope ◽  
Significant Difference ◽  
Helix Surfaces ◽  
Future Work ◽  
Oxidation Parameters

Surface modification is used to extend the life of implants. To increase the corrosion resistance and improve the biocompatibility of metal implant materials, oxidation of the Ti-13Nb-13Zr titanium alloy was used. The samples used for the research had the shape of a helix with a metric thread, with their geometry imitating a dental implant. The oxide layer was produced by a standard electrochemical method in an environment of 1M H3PO4 + 0.3% HF for 20 min, at a constant voltage of 30 V. The oxidized samples were analyzed with a scanning electron microscope. Nanotubular oxide layers with internal diameters of 30–80 nm were found. An analysis of the surface topography was performed using an optical microscope, and the Sa parameter was determined for the top of the helix and for the bottom, where a significant difference in value was observed. The presence of the modification layer, visible at the bottom of the helix, was confirmed by analyzing the sample cross-sections using computed tomography. Corrosion tests performed in the artificial saliva solution demonstrated higher corrosion current and less noble corrosion potential due to incomplete surface coverage and pitting. Necessary improved oxidation parameters will be applied in future work.

Fatigue behavior and life predictions of thermally oxidized Ti6Al4V alloy according to oxidation parameters

2021 ◽  
pp. 105737
Author(s):  
Gustavo Dória Lima ◽  
Brenno Lima Nascimento ◽  
Isau de Souza Alves Júnior ◽  
Matheus Porto Trindade ◽  
Sandro Griza
Keyword(s):  
Fatigue Behavior ◽  
Ti6al4v Alloy ◽  
Life Predictions ◽  
Oxidation Parameters

Effect of various sono-oxidation parameters on the desulfurization of diesel oil

2009 ◽  
Vol 49 (5) ◽  
pp. 436-441 ◽  
Author(s):  
Yongchuan Dai ◽  
Yutai Qi ◽  
Dezbi Zhao
Keyword(s):  
Diesel Oil ◽  
Oxidation Parameters

scholarly journals Cyclic Oxidation of Titanium Grade 2

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5431
Author(s):  
Krzysztof Aniołek ◽  
Adrian Barylski ◽  
Marian Kupka ◽  
Grzegorz Dercz
Keyword(s):  
Cyclic Oxidation ◽  
Considerable Increase ◽  
Oxidation Process ◽  
Surface Hardness ◽  
Oxide Layers ◽  
Arrhenius Diagram ◽  
Oxide Particles ◽  
Titanium Grade ◽  
Oxidation Parameters ◽  
Tio2 Rutile

This paper presents the results of research into the cyclic oxidation of titanium Grade 2. The value of titanium Grade 2 oxidation activation energy was determined based on an analysis of the Arrhenius diagram. The result was 205.3 kJ/mol. After cyclic oxidation at a temperature of 600 °C, the presence of oxides in an acicular system was observed on the surface. The specimen surface after oxidation at 650 °C was characterised by the presence of fine oxide particles, while after oxidation at 700 °C, the obtained oxide layer was composed of large oxide particles. The layers obtained after oxidation at 600 °C had the lowest thickness (1.26 and 2.12 µm), while those obtained at 700 °C had the highest thickness (5.17 and 9.45 µm). Examination of the phase composition after cyclic oxidation showed that the oxide layers obtained at temperatures of 600, 650 and 700 °C were composed of TiO2 (rutile) only. No presence of other phases was found. The oxide layers formed in the cyclic oxidation process were characterised by different thicknesses, depending on the oxidation parameters. It was found that cyclic oxidation contributed to a considerable increase in the surface hardness of titanium Grade 2.

Determination of nitrification kinetics by the ANITA-DOstat biosensor

2000 ◽  
Vol 41 (12) ◽  
pp. 121-128 ◽  
Author(s):  
E. Ficara ◽  
A. Rocco ◽  
A. Rozzi
Keyword(s):  
Flow Rate ◽  
Bacterial Respiration ◽  
Ammonium Oxidation ◽  
Constant Ph ◽  
New Instrument ◽  
Nitrification Kinetics ◽  
Do Concentration ◽  
Oxidation Parameters ◽  
H2o2 Addition

The ANITA biosensor, which measures ammonium oxidation rate by alkaline titration at constant pH, has been recently coupled to open respirometry making it possible to evaluate NH4+ oxidation kinetics by two different and completely independent techniques. This paper describes the use of a new instrument, also derived from the titration biosensor ANITA and named ANITA-DOstat, which incorporates dissolved oxygen (DO) control by H2O2 addition. The peroxide is very rapidly decomposed to H2O2 and O2 by bacterial catalase and supplies oxygen to the mixed liquor. The novelty lies not in the use of H2O2 addition as a source of oxygen for bacterial respiration, but in the measurement of kinetics by DOstat titrimetric respirometry which allows for evaluation of bacterial bio-oxidation parameters directly from the H2O2 flow rate at constant DO concentration. Preliminary results are presented on nitrification kinetics determination, for both ammonium oxidisers (AO) and nitrite oxidisers (NO), carried out by alkaline titration and by the new H2O2 DOstat titrimetric respirometry method.

Oxidation of 1,2-Propanediol to Lactic Acid under Novel Supported Au Catalysts and Reaction Kinetics

2020 ◽  
Vol 850 ◽  
pp. 41-47
Author(s):  
Svetlana Zhizhkuna ◽  
Svetlana Chornaja ◽  
Jevgenija Vladiko ◽  
Reinis Drunka ◽  
Dzidra Jankoviča ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Reaction Kinetics ◽  
Oxidation Process ◽  
Gold Catalysts ◽  
Reaction Conditions ◽  
Oxidation Parameters

This work demonstrates that 5wt% gold catalysts supported on Al2O3 and TiO2 nanopowders as well as on TiO2 nanofibers are active in the 1,2-propanediol (1,2-PDO) oxidation to lactic acid. The influence of catalysts different parameters and reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. The best result was achieved using 5wt%Au/TiO2 catalyst over the following oxidation parameters: c0(1,2-PDO) = 0.3 mol/L, n (1,2-PDO)/n (Au) = 4000 mol/mol, p (O2) = 6 bar, c0(NaOH) = 2 mol/L, t = 60 °C: 1,2-propanediol conversion was 98 % and lactic acid selectivity 89 %.

Oxidation Kinetics of 1,2-Propanediol in the Presence of Pd and Pt Catalysts

2020 ◽  
Vol 850 ◽  
pp. 48-53
Author(s):  
Svetlana Chornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko ◽  
Reinis Drunka ◽  
Aija Krūmiņa
Keyword(s):  
Lactic Acid ◽  
Molecular Oxygen ◽  
Selective Oxidation ◽  
Oxidation Kinetics ◽  
Main Product ◽  
Pt Catalysts ◽  
Acid Yield ◽  
Active Metal ◽  
Oxidation Parameters ◽  
Kinetics Of

1.25 – 5wt%Pt/Al2O3, 1.25 – 5wt%Pd/Al2O3, 1wt%Pd/TiO2, 1 – 5wt%Pd/TiO2-NF, 1.25wt%Pt+1.25wt%Pd/Al2O3, 5wt%Pt/SiO2, 5wt%Pt/C catalysts were synthesised and tested in the selective oxidation of 1,2-propanediol by molecular oxygen. It was found that all catalysts were active in alkaline water solutions; lactic acid was obtained as the main product of the reaction. The conversion of 1,2-propandiol and the yield of lactic acid depended on the content of active metal in the catalysts. The most active for the oxidation of 1,2-propandiol were palladium-containing catalysts supported on TiO2 nanofibers (Pd/TiO2-NF). The highest 1,2-propanediol conversion (100 %) and lactic acid yield (96 %) were obtained using the 5wt%Pd/TiO2-NF catalyst at the following oxidation parameters: c0(1,2-propanediol) = 0.3 mol/L, P(O2) = 1 atm, n (1,2-propanediol)/n (Pd) = 500 mol/mol, t = 60 °C, c0(NaOH) = 1.5 mol/L.

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