Determination of Air Density, Temperature and Winds at High Altitude.

1977 ◽  
Author(s):  
Gerald V. Groves
Keyword(s):  
High Altitude ◽  
Air Density

The Optical Measurement of Lapse Rate *

1950 ◽  
Vol 31 (2) ◽  
pp. 51-55 ◽  
Author(s):  
Robert G. Fleagle
Keyword(s):  
Optical Measurement ◽  
Vertical Gradient ◽  
Lapse Rate ◽  
Speed Of Light ◽  
Indirect Methods ◽  
Reliable Determination ◽  
Air Density ◽  
Lapse Rates ◽  
The Relationship

The need for reliable determination of the temperature of the air very near the ground and the difficulties inherent in measurement of this quantity by the ordinary indirect methods are pointed out. It is suggested that the dependence of the speed of light on air density provides a convenient method for the determination of the temperature near the ground by direct measurement of the lapse rate, and evidence is given from other papers to show that this is feasible where the vertical gradient of humidity is not great. The relationship between apparent elevation and lapse rates of temperature and vapor pressure is derived, and the relationship is illustrated by the results of computations.

scholarly journals New High-Altitude Study of Cosmic-Ray Bands and a New Determination of Their Total Energy Content

1933 ◽  
Vol 44 (4) ◽  
pp. 246-252 ◽  
Author(s):  
I. S. Bowen ◽  
R. A. Millikan ◽  
H. V. Neher
Keyword(s):  
Total Energy ◽  
High Altitude ◽  
Energy Content ◽  
Cosmic Ray ◽  
Total Energy Content

Accurate determination of the total alkalinity and the CO2 system parameters in high-altitude lakes from the Western Pyrenees (France – Spain)

2020 ◽  
Vol 152 ◽  
pp. 104345
Author(s):  
Leire Kortazar ◽  
Bastien Duval ◽  
Olaia Liñero ◽  
Olaia Olamendi ◽  
Ainhoa Angulo ◽  
...  
Keyword(s):  
High Altitude ◽  
Accurate Determination ◽  
Total Alkalinity ◽  
System Parameters ◽  
High Altitude Lakes ◽  
Western Pyrenees

scholarly journals Efficiency of High Altitude On-shore Wind Turbines: Air Density and Turbulence Effects—Qollpana Wind Farm (Bolivia)

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 487 ◽  
Author(s):  
Rober Mamani ◽  
Norbert Hackenberg ◽  
Patrick Hendrick
Keyword(s):  
High Altitude ◽  
Wind Turbines ◽  
Wind Farm ◽  
Air Density ◽  
Turbulence Effects

Influence of Altitude on the Performance of a Bicycle-Cyclist Set

2017 ◽  
Author(s):  
Mateo Morales ◽  
Sergio D. Roa ◽  
Luis E. Muñoz ◽  
Diego A. Ferreira ◽  
Omar D. Lopez Mejia
Keyword(s):  
High Altitude ◽  
Drag Force ◽  
Power Output ◽  
Aerodynamic Drag ◽  
Integrated Approach ◽  
Cycling Performance ◽  
Air Density ◽  
Effort Tests ◽  
Different Altitudes

There is a tradeoff between power delivery and aerodynamic drag force when cyclists ride at different altitudes. The result is particular to the characteristics of the bicycle as well as the aerobic fitness of the cyclist. This work proposes a methodology based on an integrated approach to the study of the influence of altitude on power output and aerodynamic drag over a particular bicycle-cyclist set. The methodology consists of an independent analysis for each of the effects, to conclude with an integration of results that allows estimating the overall effect of altitude on cycling performance. A case study for the application of the methodology was developed, and the obtained results apply for the specific bicycle-cyclist set under analysis. First, the relationship between power and time was analyzed for a male recreational cyclist based on all-out effort tests at two different altitudes: 237 meters and 2652 meters above sea level (m.a.s.l). Second, the effects of environmental conditions on air density and drag area coefficient due to altitude changes were analyzed based on Computational Fluid Dynamics (CFD) simulations. It was found that for the bicycle-cyclist set under study, the sustainable power output for 1-hour cycling was reduced 45W for the high-altitude condition as a consequence of the reduction in the maximum oxygen uptake capacity. In addition, the aerodynamic drag force is reduced in greater proportion due to the change in air density than due to the change in drag coefficient. Finally, the results of both effects were integrated to analyze the overall influence of altitude on cycling performance. It was found that for the analyzed case study, the aerodynamic advantage at higher altitude dominates over the disadvantage of reduction in power output: despite delivering 45W less, the subject can travel an additional distance of 900 meters during a one hour ride for the high-altitude condition compared to that in low altitude.

scholarly journals Determination of some wood properties and response to weathering of Citrus limon (L.) Burm wood

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6840-6850
Author(s):  
Sırrı Sahin ◽  
Ümit Ayata ◽  
Bekir Cihad Bal ◽  
Bruno Esteves ◽  
Ahmet Can ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Transverse Direction ◽  
Longitudinal Direction ◽  
Wood Properties ◽  
Citrus Limon ◽  
Artificial Weathering ◽  
Dense Wood ◽  
Air Density ◽  
Screw Withdrawal

The ability of Citrus limon (L.) Burm wood to be used for flooring applications was considered in this work. Selected wood properties were determined, and the response to weathering was tested. Janka hardness, density, screw withdrawal resistance, color, glossiness, and artificial weathering (144, 288, and 432 h) were determined. The wood from Citrus limon was shown to be a dense wood with air density around 830 kg/m3 and with a high Janka hardness of 138.0 N/mm2, 120.4 N/mm2, and 115.9 N/mm2 for cross, tangential, and radial sections, respectively. This opens good perspectives to this kind of wood being used for flooring. Statistical analysis showed that both Janka hardness and screw withdrawal resistance were significantly different between surfaces. Nevertheless, the homogeneity groups showed that the main differences were between the surfaces in the longitudinal direction when compared with the transverse direction. The wood is lighter than most common woods and it is mainly yellow. After weathering, the wood became darker, redder, and yellower. Glossiness decreased in the first hours of the weathering period.

Sign in / Sign up

Export Citation Format

Share Document