A Prognostics Approach Connecting Oxidation Damage to Mechanical Criteria

2021 ◽  
Author(s):  
Pontus Slottner
Keyword(s):  
Oxidation Damage

The Influence of Manufacturing Tolerances on Swirler Durability

2014 ◽  
Author(s):  
Nagaraja S. Rudrapatna ◽  
Richard R. Bohman ◽  
Jonathan K. Anderson ◽  
Rudolph Dudebout ◽  
Richard Hausen
Keyword(s):  
Damage Mechanism ◽  
Jet Fuel ◽  
Combustible Mixture ◽  
Fuel Injector ◽  
Component Level ◽  
Pareto Chart ◽  
Flow Features ◽  
Manufacturing Tolerances ◽  
Oxidation Damage ◽  
Component Assembly

Jet fuel flowing through the fuel injector is atomized and then mixed with high temperature compressed air flowing through the swirler to create a combustible mixture inside a gas turbine combustor. Individual geometric and flow features are carefully tuned at a component level to deliver optimum combustion performance. In a critical interface such as the fuel injector and swirler, manufacturing tolerances not only have an impact on combustor performance and operability but also on durability, as the relative position of the fuel injector to the swirler significantly impacts the swirler temperature. This paper studies the influence of manufacturing tolerances on component assembly and the resulting impact on swirler temperature. The oxidation damage mechanism of the swirler is used as a measure to assess swirler durability. A Pareto chart of the effect of manufacturing tolerances on metal temperature is used to highlight the key influencing parameters. Probability distribution associated with manufacturing tolerances is gathered with Monte Carlo simulation to guide the design.

Comparing Different Methods to Determine the Intergranular Oxidation Damage on a Nickel Based Superalloy

2004 ◽  
Vol 461-464 ◽  
pp. 537-544 ◽  
Author(s):  
Veronique Garat ◽  
Olivier Brucelle ◽  
Jean Marc Cloué ◽  
Veronique Rebeyrolle ◽  
Daniel Monceau ◽  
...  
Keyword(s):  
Nickel Based Superalloy ◽  
Intergranular Oxidation ◽  
Oxidation Damage

Decreased 8-oxoguanine DNA glycosylase 1 (hOGG1) expression and DNA oxidation damage induced by Cr (VI)

2019 ◽  
Vol 299 ◽  
pp. 44-51 ◽  
Author(s):  
Hailing Xia ◽  
Shibo Ying ◽  
Lingfang Feng ◽  
Haiming Wang ◽  
Chunji Yao ◽  
...  
Keyword(s):  
Dna Oxidation ◽  
Dna Glycosylase ◽  
Oxidation Damage

Fatigue–oxidation–creep damage model under axial-torsional thermo-mechanical loading

2019 ◽  
Vol 29 (5) ◽  
pp. 810-830 ◽  
Author(s):  
Dao-Hang Li ◽  
De-Guang Shang ◽  
Jin Cui ◽  
Luo-Jin Li ◽  
Ling-Wan Wang ◽  
...  
Keyword(s):  
Damage Model ◽  
Creep Damage ◽  
Fatigue Loading ◽  
Damage Mechanism ◽  
Critical Crack ◽  
Critical Crack Length ◽  
Mechanical Fatigue ◽  
Proposed Model ◽  
Oxidation Damage ◽  
Creep Damage Model

A fatigue–oxidation–creep damage model that can take into account the effect of multiaxial cyclic feature on the damage mechanism is proposed under axial-torsional thermo-mechanical fatigue loading. In the proposed model, the effects of non-proportional additional hardening on fatigue, oxidation, and creep damages are considered, and the variation of oxidation damage under different high temperature loading conditions is also described. Moreover, the intergranular creep damage needs to be equivalent to the transgranular damage before accumulating with the fatigue and oxidation damages. The fatigue, oxidation, and creep damages can be expressed as the fractions of fatigue life, critical crack length, and creep rupture time, respectively, which allows the linear accumulation of different types of damages on the basis of life fraction rule. In addition, the proposed model is validated by various fatigue experimental results, including uniaxial thermo-mechanical fatigue, axial-torsional thermo-mechanical fatigue, and isothermal axial-torsional fatigue under proportional and non-proportional loadings. The results showed that the errors are within a factor of 2.

scholarly journals Bio-Based Thermoplastic Starch Composites Reinforced by Dialdehyde Lignocellulose

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3236
Author(s):  
Peng Yin ◽  
Wen Zhou ◽  
Xin Zhang ◽  
Bin Guo ◽  
Panxin Li
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Tensile Strength ◽  
Water Resistance ◽  
Thermoplastic Starch ◽  
Contact Angles ◽  
Sem Images ◽  
Elongation At Break ◽  
Injection Process ◽  
Oxidation Damage

In order to improve the mechanical properties and water resistance of thermoplastic starch (TPS), a novel reinforcement of dialdehyde lignocellulose (DLC) was prepared via the oxidation of lignocellulose (LC) using sodium periodate. Then, the DLC-reinforced TPS composites were prepared by an extrusion and injection process using glycerol as a plasticizer. The DLC and LC were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the effects of DLC content on the properties of the DLC/TPS composites were investigated via the evaluation of SEM images, mechanical properties, thermal stability, and contact angles. XRD showed that the crystallinity of the DLC decreased due to oxidation damage to the LC. SEM showed good dispersion of the DLC in the continuous TPS phase at low amounts of DLC, which related to good mechanical properties. The tensile strength of the DLC/TPS composite reached a maximum at a DLC content of 3 wt.%, while the elongation at break of the DLC/TPS composites increased with increasing DLC content. The DLC/TPS composites had better thermal stability than the neat TPS. As the DLC content increased, the water resistance first increased, then decreased. The highest tensile strength and elongation at break reached 5.26 MPa and 111.25%, respectively, and the highest contact angle was about 90.7°.

scholarly journals Microarray Analysis of Small Extracellular Vesicle-Derived miRNAs Involved in Oxidative Stress of RPE Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Ke Mao ◽  
Xingwei Wu
Keyword(s):  
Oxidative Stress ◽  
Retinal Pigment ◽  
Extracellular Vesicle ◽  
Rpe Cells ◽  
Cellular Processes ◽  
Rna Targets ◽  
Mirna Sequencing ◽  
Significant Enrichment ◽  
Oxidation Damage ◽  
Pathway Analyses

The aim of this study was to investigate the miRNA profiles of nanosized small extracellular vesicles (sEVs) from human retinal pigment epithelial (RPE) cells under oxidative damage. ARPE-19 cells were cultured with ox-LDL (100 mg/L) or serum-free medium for 48 hours, sEVs were then extracted, and miRNA sequencing was conducted to identify the differentially expressed genes (DEGs) between the 2 groups. RNA sequence results were validated using quantitative real-time PCR. The Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes pathway, and ingenuity pathway analyses (IPA) were performed for the DEGs. Results revealed that oxidative stress inhibited RPE cell viability and promoted sEV secretion. A total of 877 DEGs from sEVs were identified, of which 272 were downregulated and 605 were upregulated. In total, 66 enriched GO terms showed that the 3 most significant enrichment terms were cellular processes (biological processes), cell (cellular component), and catalytic activity (molecular function). IPA were used to explore DEGs associated with oxidation damage and further construct a miRNA-target regulatory network. This study identified several DEGs from oxidation-stimulated RPE cells, which may act as potential RNA targets for prognosis and diagnosis of RPE degeneration.

Preparation of Water-Soluble Soy Protein-Based Surfactants by Oxidizing Disulfide Bonds

2011 ◽  
Vol 236-238 ◽  
pp. 63-66
Author(s):  
Jun Sheng Li ◽  
Wei Jing ◽  
Liu Juan Yan ◽  
Li Na Li
Keyword(s):  
Molecular Structure ◽  
Surface Activity ◽  
Disulfide Bond ◽  
Soy Protein ◽  
Disulfide Bonds ◽  
Water Soluble ◽  
Performic Acid ◽  
Protein Surface ◽  
Emulsifying Property ◽  
Oxidation Damage

In this paper, the correlations between the cleavage degree of disulfide bonds and soy protein surface activity had been studied in order to show the surface activity of soy protein. The disulfide bonds of soy protein were oxidized to sulfonic groups by performic acid. The distribution of polar and nonpolar groups, and the molecular structure of soy protein were changed because of the oxidation damage of disulfide bonds, and these changes led to changes in surface activity of soy protein. The results showed that the emulsifying property of soy protein was improved by oxidizing the disulfide bonds of protein compared with that of natural soy protein. The change of soy protein emulsifying property is closely related with the degree of the disulfide bond oxidation damage,and that was also an effective way to prepare the protein-based surfactant.

scholarly journals Tautomerization-dependent recognition and excision of oxidation damage in base-excision DNA repair

2016 ◽  
Vol 113 (28) ◽  
pp. 7792-7797 ◽  
Author(s):  
Chenxu Zhu ◽  
Lining Lu ◽  
Jun Zhang ◽  
Zongwei Yue ◽  
Jinghui Song ◽  
...  
Keyword(s):  
Dna Repair ◽  
Excision Repair ◽  
Mammalian Genome ◽  
Dna Bases ◽  
Repair Pathway ◽  
Thymine Glycol ◽  
Base Excision ◽  
Oxidation Damage ◽  
Biochemical Analyses ◽  
Base Excision Dna Repair

NEIL1 (Nei-like 1) is a DNA repair glycosylase guarding the mammalian genome against oxidized DNA bases. As the first enzymes in the base-excision repair pathway, glycosylases must recognize the cognate substrates and catalyze their excision. Here we present crystal structures of human NEIL1 bound to a range of duplex DNA. Together with computational and biochemical analyses, our results suggest that NEIL1 promotes tautomerization of thymine glycol (Tg)—a preferred substrate—for optimal binding in its active site. Moreover, this tautomerization event also facilitates NEIL1-catalyzed Tg excision. To our knowledge, the present example represents the first documented case of enzyme-promoted tautomerization for efficient substrate recognition and catalysis in an enzyme-catalyzed reaction.

Study on the Run-in Process between the Contact Line and Saddle of High-Speed Rail

2013 ◽  
Vol 800 ◽  
pp. 317-320
Author(s):  
Lian Mei Song ◽  
Li Xiao Jia
Keyword(s):  
High Temperature ◽  
Contact Line ◽  
Friction Surface ◽  
High Speed ◽  
Carbon Film ◽  
High Speed Rail ◽  
Slide Surface ◽  
Wear And Friction ◽  
Oxidation Damage ◽  
Theory Calculation

At present the wear and friction of pantograph-contact line is studied widely, while the research of the run-in process is little. In the paper they are obtained that the contact area is 0.96mm2, contact stress is 73MPa, current density is 520A/mm2, the contact resistance is 0.01583 and the contact temperature is 2797K on the surface of slide during the run-in period by the theory calculation. The high temperature of slide surface leads to the oxidation damage. While the carbon film comes into being and the friction surface is tending towards stability.

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