scholarly journals Effects of Ambient Pressure on Burning Characteristics of Gasoline: A Pilot Study

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4627
Author(s):  
Pengcheng Qin ◽  
Mingnian Wang ◽  
Zhanwen Chen ◽  
Guanfeng Yan ◽  
Tao Yan ◽  
...  
Keyword(s):  
High Altitude ◽  
Oxygen Content ◽  
Release Rate ◽  
Field Experiments ◽  
Ambient Pressure ◽  
Combustion Process ◽  
Flame Height ◽  
Low Oxygen ◽  
Initial Stage ◽  
Lower Oxygen

A fire can pose a significant threat to a building’s occupants and leads to property damage. The burning characteristics usually determine the severity of the accident. Environments in high-altitude areas feature low oxygen content and ambient pressure, which can influence the burning characteristics of combustibles. In this paper, a series of field experiments were conducted to investigate the burning characteristics of gasoline at different altitudes considering heat release rate (HRR), flame height, and smoke release rate. Results show that the combustion process can be divided into three stages: initial stage, stable stage, and attenuation stage. Lower oxygen content and ambient pressure reduce the HRR; for example, the HRR at an altitude of 4150 m is nearly half at an altitude of 500 m, contributing to a lower smoke release rate. The HRR is proportional to 1.3 power of atmospheric pressure, and a fitting equation was brought out in this paper. Flame height increases with the increase in altitude due to the demand for more oxygen during the combustion process since the oxygen content is low in high-altitude areas.

Factors influencing haemoglobin synthesis by Daphnia

1953 ◽  
Vol 141 (903) ◽  
pp. 179-189 ◽  
Keyword(s):  
High Temperature ◽  
Oxygen Content ◽  
Egg Production ◽  
Oxygen Deficiency ◽  
Ferric Hydroxide ◽  
Oxygen Affinity ◽  
The Body ◽  
Low Oxygen ◽  
Lower Oxygen ◽  
Haemoglobin Synthesis

It is known that Daphnia increases the haemoglobin content of its blood in water that has a low content of dissolved oxygen. It has now been found that a high temperature results in the synthesis of more haemoglobin than a low temperature, in waters of the same low oxygen content. The increased haemoglobin synthesis is probably due to the greater rate of metabolism of the animal at a high temperature and consequent lower oxygen concentration within the body, and to the lower oxygen affinity of haemoglobin at a high temperature resulting in a poorer oxygen supply to the tissues. It must also be due in part to the lower egg production at a high temperature and consequent lesser drain of haemoglobin from the blood into the eggs. Carbon dioxide is without influence on haemoglobin production. Duck faeces increase the haemoglobin synthesis in water of low oxygen content. This effect is not due to better nutrition. Vitamin B 12 causes a small increase in the amount of haemoglobin synthesized in response to oxygen deficiency. Iron salts added to water of low oxygen content can greatly increase the amount of haemoglobin synthesized. Ferrous salts are more effective than ferric salts. This is probably due to the ferrous ion producing ferric hydroxide in a more finely divided state than that produced by the ferric ion, so that the ferric hydroxide remains suspended in the water and available to be swallowed for a longer time. The rate of loss of haemoglobin by red animals transferred to aerated water has been studied.

scholarly journals Effects of Plateau Air Quality and Low Oxygen Content on Platelet mtDNA Methylation and High Altitude Pulmonary Edema

2021 ◽  
Vol 21 ◽  
pp. 210222
Author(s):  
Ziquan Liu ◽  
Huanhuan Cui ◽  
Lei Zhao ◽  
Fucai Ma ◽  
Yanqing Liu ◽  
...  
Keyword(s):  
Air Quality ◽  
Pulmonary Edema ◽  
High Altitude ◽  
Oxygen Content ◽  
Low Oxygen ◽  
High Altitude Pulmonary Edema

Effects of ambient pressure on the critical velocity and back-layering length in longitudinal ventilated tunnel fire

2019 ◽  
Vol 29 (7) ◽  
pp. 1017-1027
Author(s):  
Guanfeng Yan ◽  
Mingnian Wang ◽  
Li Yu ◽  
Yuan Tian
Keyword(s):  
Heat Release ◽  
High Altitude ◽  
Critical Velocity ◽  
Heat Release Rate ◽  
Release Rate ◽  
Ambient Pressure ◽  
Smoke Movement ◽  
Tunnel Fire ◽  
Longitudinal Ventilation ◽  
High Altitude Area

Nowadays, the critical velocity and back-layering length are the key parameters in longitudinal ventilation design. However, most studies research them at standard air pressure but ambient pressure decreases at high-altitude area and the reduced ambient pressure could affect the smoke movement characteristics in a tunnel fire. In order to investigate the effect of ambient pressure on the velocity and back-layering length in longitudinal ventilated tunnel, theoretical analysis was carried out first and a series of numerical simulation were conducted with varying heat release rate and ambient pressure. Results show that Li’s model is also reliable under various ambient pressures. The critical velocity under various ambient pressures would become larger with an increase in the heat release rate and would remain stable after the heat release rate reaches a certain value. At smaller heat release rate, the length of counterflow would be higher under reduced ambient pressure while it remains the same when the HRR is large. This could provide reference for tunnel ventilation design at high-altitude areas.

scholarly journals Oxygen regulation of macrophage migration inhibitory factor in human placenta

2007 ◽  
Vol 292 (1) ◽  
pp. E272-E280 ◽  
Author(s):  
Francesca Ietta ◽  
Yuanhong Wu ◽  
Roberta Romagnoli ◽  
Nima Soleymanlou ◽  
Barbara Orsini ◽  
...  
Keyword(s):  
High Altitude ◽  
Migration Inhibitory Factor ◽  
Macrophage Migration Inhibitory Factor ◽  
Inhibitory Factor ◽  
Extravillous Trophoblast ◽  
Macrophage Migration ◽  
Low Oxygen ◽  
Placental Development

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine involved in regulation of macrophage function. In addition, MIF may also play a role in murine and human reproduction. Although both first trimester trophoblast and decidua express MIF, the regulation and functional significance of this cytokine during human placental development remains unclear. We assessed MIF expression throughout normal human placental development, as well as in in vitro (chorionic villous explants) and in vivo (high altitude placentae) models of human placental hypoxia. Dimethyloxalylglycine (DMOG), which stabilizes hypoxia inducible factor-1 under normoxic conditions, was also used to mimic the effects of hypoxia on MIF expression. Quantitative real-time PCR and Western blot analysis showed high MIF protein and mRNA expression at 7–10 wk and lower levels at 11–12 wk until term. Exposure of villous explants to 3% O2 resulted in increased MIF expression and secretion relative to standard conditions (20% O2). DMOG treatment under 20% O2 increased MIF expression. In situ hybridization and immunohistochemistry showed elevated MIF expression in low oxygen-induced extravillous trophoblast cells. Finally, a significant increase in MIF transcript was observed in placental tissues from high-altitude pregnancies. Hence, three experimental models of placental hypoxia (early gestation, DMOG treatment, and high altitude) converge in stimulating increased MIF, supporting the conclusion that placental-derived MIF is an oxygen-responsive cytokine highly expressed in physiological in vivo and in in vitro low oxygen conditions.

scholarly journals Air–surface exchange of gaseous mercury over permafrost soil: an investigation at a high-altitude (4700 m a.s.l.) and remote site in the central Qinghai-Tibet Plateau

2016 ◽  
Author(s):  
Zhijia Ci ◽  
Fei Peng ◽  
Xian Xue ◽  
Xiaoshan Zhang
Keyword(s):  
High Altitude ◽  
Field Experiments ◽  
Tibet Plateau ◽  
Permafrost Soil ◽  
Remote Site ◽  
Water Addition ◽  
Surface Exchange ◽  
Entire Study ◽  
Gaseous Mercury ◽  
Qinghai Tibet Plateau

Abstract. The pattern of air–surface gaseous mercury (mainly Hg(0)) exchange in the Qinghai-Tibet Plateau (QTP) may be unique because this region is characterized by low temperature, great temperature variation, intensive solar radiation, and pronounced freeze-thaw process of permafrost soils. However, air–surface Hg(0) flux in the QTP is poorly investigated. In this study, we performed filed measurements and controlled field experiments with dynamic flux chambers technique to examine the flux, temporal variation and influencing factors of air–surface Hg(0) exchange at a high-altitude (4700 m a.s.l.) and remote site in the central QTP. The results of field measurements showed that surface soils were net emission source of Hg(0) in the entire study. Hg(0) flux showed remarkable seasonality with net high emission in the warm campaigns and net low deposition in winter campaign, and also showed the diurnal pattern with emission in daytime and deposition in nighttime, especially on days without precipitation. Rainfall events on the dry soils induced large and immediate increase in Hg(0) emission. Snowfall events did not induce the pulse of Hg(0) emission, but snow melt resulted in the immediate increase in Hg(0) emission. Daily Hg(0) fluxes on rainy or snowy days were higher than those of days without precipitation. Controlled field experiments suggested that water addition to dry soils significantly increased Hg(0) emission both in short and relatively long timescales, and also showed that UV radiation was primarily attributed to Hg(0) emission in the daytime. Our findings imply that a warm climate and environmental change could facilitate Hg release from the permafrost terrestrial ecosystem in the QTP.

Effect of the Sintering Atmosphere on the Corrosion Resistance of Titanium for Application as Biomaterial

2012 ◽  
Vol 727-728 ◽  
pp. 85-89
Author(s):  
Luzinete P. Barbosa ◽  
Elki C. Souza ◽  
Lucio Salgado ◽  
I. Costa
Keyword(s):  
Corrosion Resistance ◽  
Oxygen Content ◽  
Passive Film ◽  
Titanium Surface ◽  
Sintered Titanium ◽  
Nacl Solution ◽  
Low Oxygen ◽  
Sintering Atmosphere ◽  
Corrosion Tests ◽  
Vacuum Atmosphere

In this work, the effect of sintering atmosphere on the corrosion resistance of sintered titanium has been evaluated in 0.9 % aqueous NaCl solution to simulate physiological environment. Corrosion tests were performed on titanium porous sintered under vacuum and vacuum plus dynamic argon. The results showed better passive properties associated to the titanium sintered under argon plus vacuum atmosphere than to the vacuum sintered titanium. The better corrosion resistance of the argon plus vacuum sintered titanium was attributed to the formation of a thin passive film on the titanium surface during sintering due the low oxygen content present in this atmosphere.

scholarly journals THE MORPHOLOGICAL CHANGES IN THE TISSUES OF THE RABBIT AS A RESULT OF REDUCED OXIDATION

1918 ◽  
Vol 27 (3) ◽  
pp. 399-412 ◽  
Author(s):  
H. G. Martin ◽  
A. S. Loevenhart ◽  
C. H. Bunting
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Content ◽  
Morphological Changes ◽  
Low Oxygen ◽  
High Carbon ◽  
Red Bone Marrow ◽  
Hydropic Degeneration ◽  
Thyroid Hyperplasia ◽  
High Carbon Dioxide ◽  
Stimulation Of

Exposure of rabbits to an atmosphere of low oxygen content results in a stimulation of the cardiorespiratory systems, in an extension (hyperplasia) of red bone marrow and probably of a thyroid hyperplasia, with the further production of hydropic and hyaline degeneration in the cells of the parenchymatous organs. An atmosphere of high carbon dioxide and normal oxygen content produces, however, a stimulation of the cardiorespiratory systems, but no marrow extension and, in the concentrations used, but slight hydropic degeneration in the parenchyma of the glandular organs.

scholarly journals The Function of the Gills of Mayfly Nymphs from Different Habitats

1939 ◽  
Vol 16 (3) ◽  
pp. 363-373 ◽  
Author(s):  
C. A. WINGFIELD
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Content ◽  
The Body ◽  
Gaseous Exchange ◽  
Low Oxygen ◽  
Respiratory Mechanism ◽  
Tracheal Gills ◽  
Cloeon Dipterum ◽  
Gill Function ◽  
Oxygen Concentrations

1. The oxygen consumption of normal and gill-less nymphs of the mayflies Baetis sp., Cloeon dipterum and Ephemera vulgata has been measured at various oxygen concentrations. 2. It has been found that over the complete range of oxygen concentrations studied, the tracheal gills do not aid oxygen consumption in Baetis sp. In Cloeon dipterum, at all oxygen concentrations tested, no gaseous exchange takes place through the gills; at low oxygen concentrations, however, the gills function as an accessory respiratory mechanism in ventilating the respiratory surface of the body and so aid oxygen consumption. In Ephemera Vulgata the gills aid oxygen consumption even at high oxygen concentrations. In this species the gills may function both as true respiratory organs and as a ventilating mechanism. 3. It is shown that the differences in gill function can be related to the oxygen content of the habitat of each species.

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