Effects of the ambient oxygen concentration on WC-12Co cermet coatings fabricated by laser cladding

2021 ◽  
Vol 139 ◽  
pp. 106922
Author(s):  
Takuto Yamaguchi ◽  
Hideki Hagino
Keyword(s):  
Oxygen Concentration ◽  
Laser Cladding ◽  
Cermet Coatings ◽  
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%.

scholarly journals Microstructure and Properties of M3B2-Type Boride-Based Cermet Coatings Prepared by Laser Cladding Synthesis

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 476 ◽  
Author(s):  
Zhaowei Hu ◽  
Wenge Li ◽  
Yuantao Zhao
Keyword(s):  
Corrosion Resistance ◽  
Laser Cladding ◽  
Metal Layer ◽  
Surface Hardness ◽  
Electrochemical Corrosion ◽  
Bottom Layer ◽  
Cermet Coatings ◽  
Good Surface ◽  
Order Of Magnitude ◽  
Metal Phases

Although Q235 steel materials are widely used in offshore engineering, the service life is severely shortened by its inferior resistance to wear and corrosion in harsh marine working environments. Boride-based cermet composites could be a good surface-protective coating to enhance surface hardness, wear resistance, and corrosion resistance. M3B2 (M: Mo, Ni, Fe, Cr) boride-based cermet coatings composed of hard ceramics of M3B2-type complex borides and an {Fe, Ni} metal matrix was fabricated on Q235 steels with mixed Mo, Cr, B, and Ni60 powders using a laser cladding synthesis technique. The influences of laser cladding parameters on the microstructure, phase composition, microhardness, and corrosion resistance of the coatings were comprehensively investigated. Results showed that the microstructures of the coatings mainly consisted of three layers, which were, from the top to bottom layer, a metal layer with fewer ceramic phases, a ceramic layer with fewer metal phases, and another metal layer with fewer ceramic phases. The ceramic phases were mainly M3B2-type borides, and the metal phases were mainly {Fe, Ni} alloys. The appearance of Fe-enriching metal phases was due to the supply of Fe elements from Q235 substrates. With squash pretreatment and without a remelting aftertreatment, ceramics uniformly dispersed in the cermet coatings, and their sizes decreased. The results of microhardness showed that the microhardness of the coating first increased and then decreased from the top layer to the bottom layer, and maximum microhardness was obtained in the layer of ceramics with less metal phases. An electrochemical corrosion test showed that the cermet coatings (jcorr = 6.35 μA/cm2) could improve the corrosion resistance of Q235 steels (j = 43.76 μA/cm2) by one order of magnitude.

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

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