Turbocharged Two-Stroke-Cycle Gas Engines

1965 ◽  
Vol 87 (4) ◽  
pp. 421-438
Author(s):  
M. L. Land ◽  
Alex Carameros
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Thermal Loading ◽  
Constant Pressure ◽  
Successful Operation ◽  
Pressure System ◽  
Start Up ◽  
Load Carrying ◽  
History Of ◽  
Stroke Cycle

Pulse turbocharging, which had a long history of successful operation in sea-level installations on two-stroke-cycle gas engines, did not give satisfactory results at high altitude as evidenced by increased thermal loading and reduced load-carrying ability. Proper application of the constant-pressure system overcame these difficulties. The underlying theory explaining these results, supported by factory and field developments, is given in this paper. Start-up, operational, and maintenance experiences are given on constant-pressure-turbocharged, two-cycle, uniflow engines at high altitude.

Exercise-induced VA/Q inequality in subjects with prior high-altitude pulmonary edema

1996 ◽  
Vol 81 (2) ◽  
pp. 922-932 ◽  
Author(s):  
A. Podolsky ◽  
M. W. Eldridge ◽  
R. S. Richardson ◽  
D. R. Knight ◽  
E. C. Johnson ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Pulmonary Edema ◽  
High Altitude ◽  
Sea Level ◽  
Control Group ◽  
Pulmonary Capillary ◽  
High Altitude Pulmonary Edema ◽  
History Of ◽  
Capillary Pressures ◽  
Exercise Induced

Ventilation-perfusion (VA/Q) mismatch has been shown to increase during exercise, especially in hypoxia. A possible explanation is subclinical interstitial edema due to high pulmonary capillary pressures. We hypothesized that this may be pathogenetically similar to high-altitude pulmonary edema (HAPE) so that HAPE-susceptible people with higher vascular pressures would develop more exercise-induced VA/Q mismatch. To examine this, seven healthy people with a history of HAPE and nine with similar altitude exposure but no HAPE history (control) were studied at rest and during exercise at 35, 65, and 85% of maximum 1) at sea level and then 2) after 2 days at altitude (3,810 m) breathing both normoxic (inspired Po2 = 148 Torr) and hypoxic (inspired Po2 = 91 Torr) gas at both locations. We measured cardiac output and respiratory and inert gas exchange. In both groups, VA/Q mismatch (assessed by log standard deviation of the perfusion distribution) increased with exercise. At sea level, log standard deviation of the perfusion distribution was slightly higher in the HAPE-susceptible group than in the control group during heavy exercise. At altitude, these differences disappeared. Because a history of HAPE was associated with greater exercise-induced VA/Q mismatch and higher pulmonary capillary pressures, our findings are consistent with the hypothesis that exercise-induced mismatch is due to a temporary extravascular fluid accumulation.

scholarly journals New record of Didymocorypha Wood-Mason (Mantodea, Eremiaphilidae) from China, with description of a new high-altitude wingless mantis species in Asia

ZooKeys ◽  
2020 ◽  
Vol 922 ◽  
pp. 51-64
Author(s):  
Chao Wu ◽  
Chun-Xiang Liu
Keyword(s):  
Life History ◽  
New Species ◽  
High Altitude ◽  
South Asia ◽  
Sea Level ◽  
Northern Hemisphere ◽  
New Record ◽  
Southern Slope ◽  
History Of ◽  
One New Species

The genus Didymocorypha Wood-Mason, 1877 (Eremiaphilidae, Iridinae) has only been recorded in South Asia, including a sole species D. lanceolata (Fabricius). Here, we firstly extend its distribution to China, with description of one new species D. libaiisp. nov.Didymocorypha libaiisp. nov. lives in an area about 3000 meters above sea level on the southern slope of the Himalayas (Tibet in China), one of the highest-altitude inhabited areas of mantis in the Northern Hemisphere. It is also the first recorded Oriental mantis species in which both sexes are wingless. Life history of the new species, necessary illustrations and ecological images are provided. The distribution of the new Didymocorypha species is discussed and mapped.

scholarly journals Exercise Responses to Metabolic Function on High Altitude Pulmonary Edema Susceptible Individuals

2018 ◽  
Vol 3 (3) ◽  
pp. 224
Author(s):  
Kaushik Halder ◽  
RK Gupta ◽  
Anjana Pathak ◽  
Montu Saha
Keyword(s):  
Pulmonary Edema ◽  
High Altitude ◽  
Sea Level ◽  
Past History ◽  
Minute Ventilation ◽  
Metabolic Responses ◽  
Prior History ◽  
High Altitude Pulmonary Edema ◽  
History Of ◽  
Exercise Induced

<p>The study was aimed to evaluate and compare resting and exercise induced metabolic responses between acclimatized high altitude pulmonary edema (HAPE) susceptible (HAPE-s) and HAPE resistance (HAPE-r) volunteers at sea level. A group of 14 Indian soldiers volunteered for this study, divided into two groups, (i) HAPE-s, with past history of HAPE [n<sub>1</sub> = 7; age = 33.3 ± 4.5 (M ± SD)] and (ii) HAPE-r, with prior history of repeated exposure to high altitude and without suffering HAPE [n<sub>2</sub> = 7; age = 31.9 ± 4.2 (M ± SD)]. Respiratory frequency (f<sub>R</sub>), tidal volume (<sub>T</sub>), minute ventilation (<sub>E</sub>), oxygen consumption (O<sub>2</sub>), carbon dioxide output (CO<sub>2</sub>), heart rate (HR) and respiratory quotient (RQ) were recorded on all the volunteers during resting and exercise conditions. Ventilatory equivalent for oxygen (EqO<sub>2</sub>) and oxygen pulse (O<sub>2</sub>P) were calculated. Significant differences were observed between HAPE-s and HAPE-r volunteers in f<sub>Rrest </sub>(25.3% higher), O<sub>2</sub>P<sub>rest </sub>(23.7% lower), <sub>Emax</sub> (50.9% lower) (all P&lt;0.05), f<sub>Rmax </sub>(55.7% lower), O<sub>2max </sub>(55.5% lower), O<sub>2</sub>P<sub>max </sub>(34.2% lower) (all P&lt;0.01) and CO<sub>2max</sub> (42.1% lower, P&lt;0.001). Rest of the parameters did not show any significant differences between the study groups. The study revealed that resting and exercise induced metabolic responses of HAPE-r volunteers was better as compared to acclimatized HAPE-s volunteers at sea level.</p>

The earliest human occupation of the high-altitude Tibetan Plateau 40 thousand to 30 thousand years ago

Science ◽  
2018 ◽  
Vol 362 (6418) ◽  
pp. 1049-1051 ◽  
Author(s):  
X. L. Zhang ◽  
B. B. Ha ◽  
S. J. Wang ◽  
Z. J. Chen ◽  
J. Y. Ge ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
High Altitude ◽  
Sea Level ◽  
Archaeological Site ◽  
The Tibetan Plateau ◽  
Human Occupation ◽  
Modern Humans ◽  
The World ◽  
History Of

The Tibetan Plateau is the highest and one of the most demanding environments ever inhabited by humans. We investigated the timing and mechanisms of its initial colonization at the Nwya Devu site, located nearly 4600 meters above sea level. This site, dating from 40,000 to 30,000 years ago, is the highest Paleolithic archaeological site yet identified globally. Nwya Devu has yielded an abundant blade tool assemblage, indicating hitherto-unknown capacities for the survival of modern humans who camped in this environment. This site deepens the history of the peopling of the “roof of the world” and the antiquity of human high-altitude occupations more generally.

Phanerozoic Oxygen

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Oxygen Consumption ◽  
Organic Carbon ◽  
Sea Level ◽  
Time Scale ◽  
Atmospheric Oxygen ◽  
Sea Level Change ◽  
Oxygen Production ◽  
Level Change ◽  
History Of ◽  
Geologic Processes

This chapter discusses the modeling of the history of atmospheric oxygen. The most recently deposited sediments will also be the most prone to weathering through processes like sea-level change or uplift of the land. Thus, through rapid recycling, high rates of oxygen production through the burial of organic-rich sediments will quickly lead to high rates of oxygen consumption through the exposure of these organic-rich sediments to weathering. From a modeling perspective, rapid recycling helps to dampen oxygen changes. This is important because the fluxes of oxygen through the atmosphere during organic carbon and pyrite burial, and by weathering, are huge compared to the relatively small amounts of oxygen in the atmosphere. Thus, all of the oxygen in the present atmosphere is cycled through geologic processes of oxygen liberation (organic carbon and pyrite burial) and consumption (weathering) on a time scale of about 2 to 3 million years.

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