Numerical Model for Nitrogen Tire Inflation5

2007 ◽  
Vol 35 (4) ◽  
pp. 300-316
Author(s):  
Kevin R. J. Ellwood ◽  
John Baldwin ◽  
David R. Bauer
Keyword(s):  
Nitrogen Concentration ◽  
Inflation Pressure ◽  
Aging Behavior ◽  
Pure Nitrogen ◽  
Aging Rate ◽  
Oxidative Aging ◽  
Diffusion Limited ◽  
Lower Oxygen ◽  
Aging Rates ◽  
Lower Oxygen Concentration

Abstract The scope of this study was twofold: (1) to quantify the contribution nitrogen inflation would have on oxidative aging of tires and (2) measure the improvement nitrogen tire inflation may have on inflation pressure retention. A previously developed tool for diffusion-limited oxidation was used to simulate aging behavior at 25 and 60 °C. Oven-accelerated tire aging (60 °C) data for different inflation media was used for successful validation of the model, and it was shown that aging rates for higher oxygen concentrations tend toward a constant value. For lower temperatures, the use of nitrogen was shown to produce lower oxygen concentration in the wedge and bead regions of the tire geometry considered when compared to air inflation. By using 95% pure nitrogen (that is, the actual nitrogen concentration in the tire cavity), a 25% reduction in aging rate (for the tire wedge) and a 35% reduction in the initial flux of mass out of the tire (a measure of inflation pressure retention) were calculated.

Thermal-oxidative aging behavior of nitrile-butadiene rubber/functional LDHs composites

2016 ◽  
Vol 133 ◽  
pp. 219-226 ◽  
Author(s):  
Xianru He ◽  
Tianxiang Li ◽  
Zhengren Shi ◽  
Xin Wang ◽  
Fei Xue ◽  
...  
Keyword(s):  
Butadiene Rubber ◽  
Aging Behavior ◽  
Oxidative Aging ◽  
Nitrile Butadiene Rubber ◽  
Thermal Oxidative Aging

Stress-accelerated photothermal oxidative aging behavior of polyamide 6

2013 ◽  
Vol 27 (11) ◽  
pp. 1573-1586
Author(s):  
Xiaowen Zhao ◽  
Xiaohe Li ◽  
Lin Ye ◽  
Guangxian Li
Keyword(s):  
Polyamide 6 ◽  
Aging Behavior ◽  
Oxidative Aging

Morphology controlled deposition of ZnO single micro-nanorods

2019 ◽  
Vol 9 (5) ◽  
pp. 524-528
Author(s):  
Lina Wang ◽  
Ailing Zou ◽  
Jitong Liu ◽  
Jing Wang ◽  
Dan Zhou ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Chemical Vapor ◽  
Hexagonal Wurtzite Structure ◽  
Chemical Vapor Deposition Method ◽  
Oxygen Defect ◽  
Simple Chemical ◽  
Lower Oxygen ◽  
Controlled Deposition ◽  
Extrinsic Feature ◽  
Lower Oxygen Concentration

The ZnO micro-nanorods are controlledly synthesized by a simple chemical vapor deposition method. With different oxygen concentrations the micro-nanorods exhibit different extrinsic feature and length. Under lower oxygen concentration, the micro-nanorods are up to 1670 μm in length which can be easily operated in singlecrystalline. When the oxygen concentration up to 30 sccm, the surface of the sample is smoother. The Raman spectra reveal that ZnO micro-nanorods have an excellent hexagonal wurtzite structure. However, the micronanorods synthesized during lower oxygen concentration exhibit more oxygen defect. The morphology controlling deposition of ZnO mircro-nanorods were realized by adjust the concentration of oxygen, which has great significance for further gas sensor application.

scholarly journals Laser Surface Nitriding of Ti–6Al–4V Alloy in Nitrogen–Argon Atmospheres

Coatings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1009
Author(s):  
Guang Li ◽  
Xiaochun Yao ◽  
Richard James Wood ◽  
Jinchang Guo ◽  
Yu Shi
Keyword(s):  
Surface Roughness ◽  
Nitrided Layer ◽  
Nitrogen Concentration ◽  
Nitrogen Atmosphere ◽  
Argon Atmosphere ◽  
Laser Surface ◽  
Mixed Gas ◽  
Transverse Cracks ◽  
Pure Nitrogen ◽  
Argon Concentration

Surface-nitrided layers of Ti–6Al–4V alloy were fabricated using a diode laser in pure and mixed gas atmospheres of nitrogen and argon. The surface morphology, microstructure, hardness, and cracks of the nitrided layers were investigated. In all gas atmospheres, the layers showed smooth and humped regions, and consisted of planar nitrogen titanium (TiN), dendrites, and acicular martensite. The surface roughness was improved dramatically as the nitrogen concentration of the atmosphere was diluted with argon. Overall, the hardness of the nitrided layer was greatest for pure nitrogen and it tended to decrease as the concentration of argon in the atmosphere increased. However, the hardness of the layer for pure nitrogen also decreased rapidly, from the surface to matrix, in comparison to the diluted nitrogen atmospheres. It was shown that the number and size of dendrites, which determine hardness, are controlled by the nitrogen concentration. The dendrites of the nitrided layer were denser and smaller in a pure nitrogen atmosphere, than in diluted nitrogen atmospheres. Longitudinal and transverse cracks were observed in the nitrided layers. These two types of cracks were decreased or even eliminated as the argon concentration of the nitrogen–argon atmosphere was increased. Therefore, by diluting the nitrogen atmosphere with argon, the nitrided layer properties, in terms of surface roughness and cracks, can be improved, but this may also cause a reduction in the layer hardness.

Stress–thermal oxidative aging behavior of hydrogenated nitrile rubber seals

2018 ◽  
Vol 136 (7) ◽  
pp. 47014 ◽  
Author(s):  
W. Lou ◽  
W. Zhang ◽  
T. Jin ◽  
X. Liu ◽  
H. Wang
Keyword(s):  
Nitrile Rubber ◽  
Aging Behavior ◽  
Oxidative Aging ◽  
Thermal Oxidative Aging

Aging Characteristics of Ferroelectric Epitaxial BaTiO3/YBa2Cu3O7 Heterostructures

1994 ◽  
Vol 341 ◽  
Author(s):  
Samuel D. Harkness ◽  
J. W Viatella ◽  
V. Nagabushnam ◽  
R. K. Singh
Keyword(s):  
Lattice Strain ◽  
Microstructural Analysis ◽  
Laser Deposition ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
Impedance Analyzer ◽  
Aging Rate ◽  
X Ray ◽  
Aging Rates ◽  
D 02

AbstractThe nature of ferroelectric aging of epitaxial BaTiO3YBa2Cu3O7 heterostructures grown by laser deposition was investigated as a function of rricrostructure in the dielctric layer. Molar amounts of SrTiO3 were then substitutionally added to analyze the effect on the rnicrostructure and electrical properties. Corresponding shifts in c/a ratio and curie temperature were correlated to changes in aging rate (%δC/decade time). Microstructural analysis was provided by high-resolution x-ray diffraction (HRXRD), and Rutherford backscattering spectroscopy (RBS). Results indicate a moderate upward shift in c/a ratios from theoretical values due to increasing lattice strain across the bilayer interface. Minimum channel yields in RBS spectra were maintained between 6–8% for BaTiO3 purities above 60 %. Dielectric measurements were conducted using an impedance analyzer equipped with an isothermal chamber capable of maintaining ±1°C. The dielectric properies were consistent with c-axis oriented BaTiO3 values (k=120, D=.02)Minimum aging rates are observed at the lower c/a ratio compositions to be as low as .07%δC/decade.

A nitric oxide-sensitive electrode: Requirement of lower oxygen concentration for detecting nitric oxide from the tissue

1996 ◽  
Vol 35 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Yukisato Ishida ◽  
Michio Hashimoto ◽  
Shoju Fukushima ◽  
Sumio Masumura ◽  
Tetsuya Sasaki ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Oxygen Concentration ◽  
Lower Oxygen ◽  
Sensitive Electrode ◽  
Lower Oxygen Concentration

scholarly journals Aging Across the Lifespan: Rethinking the David Barker Hypothesis

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 32-32
Author(s):  
Luigi Ferrucci
Keyword(s):  
Geriatric Medicine ◽  
Life Course Perspective ◽  
Biomedical Science ◽  
Model Organisms ◽  
Biological Aging ◽  
Aging Rate ◽  
Clear Cut ◽  
Health And Wellbeing ◽  
Aging Rates

Abstract For many years, the scope of geriatric medicine has been the care of older persons affected by multiple disease with the aim of improving their functional status and optimize quality of life. As our knowledge of the mechanisms of aging grows rapidly, it is becoming clear that accomplishing this scope requires taking a life-course perspective. Research have failed to establish a clear-cut distinction between normal aging and pathology leading to the hypothesis that aging is at the root of chronic diseases, and difference in health can be ascribed to different aging rates. Research in model organisms, suggest that aging can be modified with consequent changes on healthspan and longevity. Interventions that modulate aging may ultimately prevent most-age-associated diseases and their consequences. From this perspective, geriatric medicine is the leading and most promising branch of biomedical science. Challenges remain: first, demonstrating that certain interventions slow down the aging rate requires the valid measure of aging, and while many tools were developed, “epigenetic clocks” being the most promising, the underline mechanism that drive their changes with aging and validity in clinical applications are unclear. We do not know whether variability in the rate of biological aging assessed in old age are already detectable in younger individuals and person-specific rates remain constant during life. In 1986, David Barker stated the hypothesis that the period of gestation, characterized by a strong epigenetic imprinting, affects health and wellbeing across life, perhaps by setting the aging rate. Perhaps pediatric and geriatric medicine are more connected than previously believed.

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