scholarly journals Oxygen Partial Pressure and Oxygen Concentration Flammability: Can They Be Correlated?

2016 ◽  
pp. 413-427
Author(s):  
Susana A. Harper ◽  
Alfredo Juarez ◽  
Horacio Perez III ◽  
David B. Hirsch ◽  
Harold D. Beeson
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Concentration

Thermodynamic analysis of oxidation during selective laser melting of pure titanium

2020 ◽  
Vol 26 (8) ◽  
pp. 1401-1404
Author(s):  
Won-Hyuk Lee ◽  
Tae-Wook Na ◽  
Kyung-Woo Yi ◽  
Seung-Min Yang ◽  
Jang-Won Kang ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Concentration ◽  
Oxidation Behavior ◽  
Pure Titanium ◽  
Initial Powder ◽  
Laser Melting ◽  
Content Type ◽  
Equilibrium Oxygen ◽  
Equilibrium Oxygen Partial Pressure

Purpose When a pure titanium component is fabricated in a selective laser melting (SLM) process using titanium powder, the oxygen concentration of the SLM sample increases compared to the initial powder. The purpose of this paper is to study the reason for increasing oxygen concentration after SLM. Design/methodology/approach To understand this phenomenon, the authors analyzed the oxidation behavior during the SLM process thermodynamically. Findings Based on the laser parameters used in this study, the temperature of the Ti melt during the SLM process was expected to rise to 2,150°C. Based on the thermodynamic analysis, the equilibrium oxygen partial pressure for oxidation was 2.32 × 10−19 atm at 2,150°C when the dissolved oxygen concentration in the titanium is 0.2 wt.%. However, the oxygen partial pressure inside the SLM chamber was 1 × 10−3 atm, which is much higher than the equilibrium oxygen partial pressure. Therefore, oxidation occurred during the SLM process, and the oxygen concentration of the SLM sample increased compared to the initial powder. Originality/value Most studies on fabricating Ti components using additive manufacturing (AM) have been focused on how the changes in the microstructures and mechanical properties depend on the process parameters. However, there are a few studies that analyzed the oxygen concentration change of Ti during the AM process and its causes. In this study, the authors analyzed the oxidation behavior during the SLM process thermodynamically.

Near Total Blood Exchange with Perfluorochemical Preparations

1987 ◽  
Vol 110 ◽  
Author(s):  
Robert P. Geyer ◽  
Kenneth Taylor ◽  
Robert Eccles ◽  
Therese Zerbonne ◽  
Anna Gallagher ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Nonionic Surfactant ◽  
Oxygen Concentration ◽  
Volume Percent ◽  
Total Blood ◽  
Subsequent Period ◽  
Blood Exchange ◽  
Emulsifying Agent ◽  
Mixed Venous

AbstractNear total blood replacement in rats has been accomplished with perfluorochemical (PFC) preparations containing hydroxyethylstarch and electrolytes. F-dimethyladamantane (F-DMA) was used alone or mixed with F-N,N-dimethylcyclohexylmethylamine (F-CHA). These compounds were emulsified to yield particles approximately 150 to 250 nanometers in diameter. The nonionic surfactant, Pluronic F68, was used as the emulsifying agent. Over ninety percent of the rats survived when their hematocrits were taken to 3 volume percent or lower from a pre-perfusion value of about 44 volume percent. In spite of the reduction in total mixed venous oxygen concentration, the oxygen partial pressure rose. During the perfusion the rats breathed 100 percent oxygen, but during the subsequent period this was decreased 10 percent per day. Six to 7 days later the hematocrits had risen to 30 to 40 volume percent. Thereafter the animals continued to develop and grow.

Effect of Oxygen Potential on Crack Growth in Alloys for Advanced Energy Systems

2008 ◽  
Author(s):  
Julian K. Benz ◽  
J. H. Kim ◽  
Ronald G. Ballinger
Keyword(s):  
Growth Rate ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Crack Growth ◽  
Oxygen Concentration ◽  
Crack Path ◽  
Fatigue Loading ◽  
Effect Of Oxygen ◽  
Static Conditions

The effect of oxygen partial pressure on fatigue and SCC growth rates in alloy 617 has been studied using both static and fatigue loading @ 650°C over the oxygen partial pressure range 10−19–10−2 atm. Tests were conducted at either constant stress intensity factor, K, for static conditions or constant ΔK in fatigue. Oxygen concentration was measured on both the inlet and outlet as well as in-situ with a probe located directly at the specimen surface. For fatigue loading the crack path was observed to be transgranular but crystallographic with a decreasing growth rate as the oxygen concentration decreased. However, for static loading the crack path shifted to intergranular and exhibited an increasing crack growth rate with decreasing oxygen concentration.

Effect of Oxygen Potential on Crack Growth in Alloys for Advanced Energy Systems

2010 ◽  
Vol 132 (10) ◽  
Author(s):  
Julian K. Benz ◽  
Ji Hyun Kim ◽  
Ronald G. Ballinger
Keyword(s):  
Growth Rate ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Crack Growth ◽  
Oxygen Concentration ◽  
Crack Path ◽  
Fatigue Loading ◽  
Effect Of Oxygen ◽  
Static Conditions

The effect of oxygen partial pressure on crack growth rates in Alloy 617 has been studied using both static and fatigue loadings at 650°C over the oxygen partial pressure range 10−19−10−3 atm. Tests were conducted at either the constant stress intensity factor K for static conditions or the constant ΔK in fatigue. Oxygen concentration was measured on both the inlet and outlet of the test retort as well as in situ with a probe located directly at the specimen surface. For fatigue loading the crack path was observed to be transgranular but crystallographic with a decreasing growth rate as the oxygen concentration decreased. However, for static loading the crack path shifted to intergranular at the same Kmax (fatigue) and exhibited what appears to be an increasing crack growth rate with decreasing oxygen concentration.

scholarly journals Effect Of Annealing On The Behavior Of Oxygen Dissolved In Germanium And Optical Properties Of Single Crystals

2016 ◽  
Vol 1 (1) ◽  
pp. 142
Author(s):  
A.F. Shimanskii ◽  
O.I. Podkopaev ◽  
T.O. Pavluk ◽  
S.A. Kopytkova ◽  
A. N. Gorodishcheva ◽  
...  
Keyword(s):  
Optical Properties ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Single Crystals ◽  
Oxygen Concentration ◽  
Annealing Effect ◽  
Infrared Spectrometry ◽  
Interstitial Oxygen ◽  
Band Maximum ◽  
Oxygen Band

<p>The annealing effect in the temperature range from 350 to 450 °С on the behavior of interstitial oxygen О<sub>i</sub> dissolved in germanium and on optical properties of single crystals has been investigated by Fourier transformed infrared spectrometry. It was found that oxygen band maximum of 843 cm<sup>–1</sup> shifted toward the 856 cm<sup>−1</sup> with oxygen concentration increasing after annealing at the oxygen partial pressure ranged from 1 to 10<sup>3</sup> Pа. The annealing at lower  values led to the decrease of 843 cm<sup>–1</sup> band intensity due to the formation of thermal donors (TD) on the basis of dissolved oxygen atoms О<sub>i</sub>. It was established that TD formation and the decrease of unbound oxygen concentration affected optical properties of the crystals.</p>

Optrode Type Oxygen Sensor

1993 ◽  
Vol 5 (3) ◽  
pp. 214-219
Author(s):  
Eiji Toba ◽  
◽  
Masayo Ichikawa
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Concentration ◽  
Whole Blood ◽  
Emission Intensity ◽  
Oxygen Sensor ◽  
Fiber Optic ◽  
Luminescent Material ◽  
Gas Phases

This paper describes a fiber optic oxygen sensor using phosphorescence and its application to clinical examinations. Since the quenching ratio of phosphorescence is proportional to oxygen partial pressure by the SternVolmer's formula, it is possible to estimate the oxygen concentration from the measured emission intensity. Combining an optical bundle with a luminescent material: Ru(bpy)32+/Nafion membrane, we have fabricated a luminous probe. This probe was experimentally investigated and was observed as having the characteristics of an oxygen concentration sensor in visible light. The probes were demonstrated to have certain advantages for example they can be operated in both liquid and gas phases. Also, they are stable to pH and flow velocities. As a clinical application, the probe can reliably measure oxygen concentrations of whole blood in vivo.

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