Defect formation caused by a transient decrease in the ambient oxygen concentration during growth of YBa2Cu3O7−δfilms

1990 ◽  
Vol 57 (22) ◽  
pp. 2365-2367 ◽  
Author(s):  
A. Gupta ◽  
B. W. Hussey ◽  
A. Kussmaul ◽  
A. Segmüller
Keyword(s):  
Oxygen Concentration ◽  
Defect Formation ◽  
Transient Decrease ◽  
Ambient Oxygen

Effects of Ambient Temperature and Oxygen Concentration on Soot Evolution in Diesel Spray Combustion

Volume 4 ◽  
2004 ◽  
Author(s):  
Yi Xu ◽  
Chia-Fon F. Lee
Keyword(s):  
Ambient Temperature ◽  
Heat Release ◽  
Oxygen Concentration ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Premixed Combustion ◽  
Ambient Oxygen ◽  
Lower Heat ◽  
Soot Measurement

A newly developed Forward Illumination Light Extinction (FILE) soot measurement technique was applied in a constant volume spray chamber to study the effects of ambient temperature and oxygen concentration on soot evolution in diesel combustion. The FILE technique with the capability of two-dimensional time-resolved quantitative soot measurement provides the much-needed information to investigate the soot formation mechanism. The ambient temperatures of 1200K, 1000K and 800K were tested to study the temperature effects on soot formation. A decrease of ambient temperature results in a longer ignition delay, which promotes a larger premixed combustion zone combining with higher heat release rates. The change of ambient temperature from 1200K to 800K increases the fuel portion burnt in the premixed combustion period. At 800K, combustion is dominated by the premixed combustion and much less soot is formed. Diesel combustion with 21% and 15% ambient oxygen concentration was also studied. With lower ambient oxygen concentration, the combustion process is basically not changed, but expands into a longer time span with a lower heat release rate. The lower heat release rate results in a lower flame temperature, which benefits the NOx emission control. However, with about the same amount of soot within the flame, and much longer soot life, soot has more chance to escape to the exhaust.

Influence of some factors on oxygen uptake of canine cardiac Purkinje fibers

1963 ◽  
Vol 204 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Kalman Greenspan ◽  
Paul F. Cranefield
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Diffusion Limitation ◽  
Purkinje Fibers ◽  
Ambient Oxygen ◽  
Cardiac Purkinje Fibers ◽  
Lower Oxygen ◽  
Wet Weight ◽  
Oxygen Tensions ◽  
Oxygen Concentrations

The rate of oxygen uptake of quiescent Purkinje fibers of the dog's heart was determined using a flow respirometer and oxygen polarography. At ambient oxygen concentrations of 60% or higher the rate of uptake was 0.739 mm3/mg wet weight per hr at 35 C. The temperature coefficient over the range 25–35° was 2.3. The uptake was independent of the ambient oxygen concentration at oxygen concentrations equal to or greater than 60% of an atmosphere. In lower oxygen concentrations the rate of uptake was found to be depressed. The depression of uptake in the lower oxygen tensions is probably the result of diffusion limitation; it may, however, reflect dependence of resting uptake on oxygen concentration.

Effects of ambient oxygen concentration on biodiesel and diesel spray combustion under simulated engine conditions

Energy ◽  
2013 ◽  
Vol 57 ◽  
pp. 722-732 ◽  
Author(s):  
Ji Zhang ◽  
Wei Jing ◽  
William L. Roberts ◽  
Tiegang Fang
Keyword(s):  
Oxygen Concentration ◽  
Diesel Spray ◽  
Spray Combustion ◽  
Ambient Oxygen

Comparative Study on Spray Auto-Ignition of Di-n-Butyl Ether and Diesel Blends at Engine-Like Conditions

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Yuanhang Guan ◽  
Wang Liu ◽  
Dong Han
Keyword(s):  
Heat Release ◽  
Oxygen Concentration ◽  
Pressure Rise ◽  
Fuel Spray ◽  
Release Rates ◽  
Butyl Ether ◽  
Auto Ignition ◽  
Ambient Oxygen ◽  
Ignition And Combustion ◽  
Oxygen Concentrations

Abstract Di-n-butyl ether (DBE), a promising lignocellulosic biofuel, has been suggested as a potential alternative fuel for compression ignition engines. In this study, the spray auto-ignition characteristics of diesel/DBE blends were experimentally measured on a constant volume combustion chamber. Time-resolved pressure traces and heat release rates in fuel spray combustion were measured at changed fuel blending fractions, ambient temperatures, and oxygen concentrations. Further, ignition delay and combustion delay that evaluates fuel spray ignition tendency were derived and compared for different test blends. Experimental results indicated that fuel spray ignition tendency is promoted with DBE addition, evidenced by the advanced pressure rise and heat release processes, and the shortened ignition and combustion delays. Peak heat release rates are fuel-dependent at high ambient oxygen concentrations since the relative fractions of the premixed and diffusive burns alter with changed DBE addition. However, as the oxygen concentration drops to 11%, fuel effects on the peak heat release rates become less noticeable. Reduced ambient oxygen concentration effectively extends fuel ignition and combustion delays, and typical two-stage pressure rises and heat releases are observed for all test blends, as the oxygen concentration drops to 11%.

Effect of ambient oxygen on growth and reproduction in Nile tilapia (Oreochromis niloticus)

2008 ◽  
Vol 65 (7) ◽  
pp. 1413-1424 ◽  
Author(s):  
Jeppe Kolding ◽  
Lise Haug ◽  
Sigurd Stefansson
Keyword(s):  
Oxygen Concentration ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Gonadosomatic Index ◽  
Size At Maturity ◽  
Low Oxygen ◽  
Asymptotic Size ◽  
Ambient Oxygen ◽  
Nile Tilapia Oreochromis Niloticus ◽  
First Maturity

Growth, size at maturity, gonadosomatic index (GSI), egg size, and absolute fecundity of Nile tilapia ( Oreochromis niloticus ) were significantly affected by oxygen levels (1.5 ± 1.0, 2.8 ± 1.4, and 6.0 ± 1.8 mg·L–1) in a controlled experiment designed to test the hypothesis (D. Pauly. 1984. J. Cons. Int. Explor. Mer, 41: 280–284) that O2 is the controlling factor for the transition from juvenile to adult in fish, in general, in the context of phenotypic life history plasticity and “stunting” in tilapias. Size at maturity and the estimated asymptotic size decreased with decreasing O2 concentration, as predicted by Pauly’s hypothesis. All fish matured at the same age (18 weeks old), which is in contrast to conventional definitions of stunting. This finding challenges the suggested plasticity in age at first maturity for tilapia. The results also challenge the hypothesis that stunting is a unique recruitment mechanism, as the smaller fish in the group with low oxygen concentration produced smaller and fewer eggs than the larger fish in the group with high oxygen concentration.

IMPRINT-MOLD-CLEANING BY VACUUM ULTRAVIOLET LIGHT

2010 ◽  
Vol 19 (04) ◽  
pp. 773-779 ◽  
Author(s):  
MASASHI NAKAO ◽  
MASANORI YAMAGUCHI ◽  
SHINTARO YABU
Keyword(s):  
Substrate Temperature ◽  
Ultraviolet Light ◽  
Oxygen Concentration ◽  
Vacuum Ultraviolet ◽  
Organic Substances ◽  
Ambient Oxygen ◽  
Temperature Radiation

Imprinted molds which are contaminated by organic substances such as UV-resins through many times of imprinting processes are successfully cleaned with irradiation of a vacuum ultraviolet (VUV, λ = 172 nm) light. Substrate temperature, radiation distance, and ambient oxygen concentration are also revealed as important factors to clean the molds.

Oxygen Supplement During Endotracheal Intubation of the Infant

PEDIATRICS ◽  
1977 ◽  
Vol 59 (6) ◽  
pp. 1046-1048
Author(s):  
Jen-Tien Wung ◽  
Raymond I. Stark ◽  
Leonard Indyk ◽  
John M. Driscoll
Keyword(s):  
Mechanical Ventilation ◽  
General Anesthesia ◽  
Endotracheal Intubation ◽  
Oxygen Concentration ◽  
Subcutaneous Emphysema ◽  
Oxygen Supply ◽  
Nasal Passage ◽  
Prolonged Administration ◽  
Ambient Oxygen ◽  
Oxygen Supplement

Endotracheal intubation is indicated for maintaining an efficient airway, for preventing aspiration and permitting pulmonary toilet, and for prolonged administration of mechanical ventilation or general anesthesia for many types of operations.1,2 Laryngoscopy and intubation may result in injury to the lips, gums, tongue, nasal passage, larynx, or trachea. Additional complications include mediastinal and subcutaneous emphysema and pneumothorax.3 These complications can be minimized if hypoxia can be prevented and laryngoscopy is performed in an unhurried manner. Patients who require a high ambient oxygen concentration in order to maintain an adequate PO2 usually react rapidly to an interruption of the oxygen supply by developing bradycardia and hypoxia. See Image in the PDFfile

scholarly journals Factors Involved In Dental Surgery Fires: A Review of the Literature

2014 ◽  
Vol 61 (1) ◽  
pp. 21-25 ◽  
Author(s):  
Andrea M. VanCleave ◽  
James E. Jones ◽  
James D. McGlothlin ◽  
Mark A. Saxen ◽  
Brian J. Sanders ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Significant Risk ◽  
Supplemental Oxygen ◽  
Review Of The Literature ◽  
Worst Case ◽  
In Vivo Models ◽  
Dental Surgery ◽  
Ambient Oxygen ◽  
Dental Practitioners

Abstract Surgical fires are well-characterized, readily preventable, potentially devastating operating room catastrophes that continue to occur from 20 to 100 times per year or, by one estimate, up to 600 times per year in US operating rooms, sometimes with fatal results. The most significant risk factors for surgical fires involve (a) the use of an ignition source, such as laser or electrocautery equipment, in or around an oxygen-enriched environment in the head, neck, and upper torso area and (b) the concurrent delivery of supplemental oxygen, especially via nasal cannula. Nonetheless, while these 2 conditions occur very commonly in dental surgery, especially in pediatric dental surgery where sedation and anesthesia are regularly indicated, there is a general absence of documented dental surgical fires in the literature. Barring the possibility of underreporting for fear of litigation, this may suggest that there is another mechanism or mechanisms present in dental or pediatric dental surgery that mitigates this worst-case risk of surgical fires. Some possible explanations for this include: greater fire safety awareness by dental practitioners, incidental ventilation of oxygen-enriched environments in patient oral cavities due to breathing, or suction used by dental practitioners during procedures. This review of the literature provides a background to suggest that the practice of using intraoral suction in conjunction with the use of supplemental oxygen during dental procedures may alter the conditions needed for the initiation of intraoral fires. To date, there appear to be no published studies describing the ability of intraoral suctioning devices to alter the ambient oxygen concentration in an intraoral environment. In vivo models that would allow examination of intraoral suction on the ambient oxygen concentration in a simulated intraoral environment may then provide a valuable foundation for evaluating the safety of current clinical dental surgical practices, particularly in regard to the treatment of children.

Sign in / Sign up

Export Citation Format

Share Document