Optical wave distortion at perturbations of air density near aircrafts with subsonic velocities

2017 ◽  
Author(s):  
Artem A. Sukharev ◽  
Viktor Banakh
Keyword(s):  
Optical Wave ◽  
Air Density ◽  
Wave Distortion

scholarly journals Features of adaptive phase correction of optical wave distortion under conditions of intensity fluctuations

2019 ◽  
Vol 1368 ◽  
pp. 022064
Author(s):  
N N Botygina ◽  
O N Emaleev ◽  
V V Lavrinov ◽  
V P Lukin ◽  
A A Selin ◽  
...  
Keyword(s):  
Phase Correction ◽  
Optical Wave ◽  
Wave Distortion ◽  
Intensity Fluctuations

scholarly journals Elevational niche-shift migration: Why the degree of elevational change matters for the ecology, evolution, and physiology of migratory birds

The Auk ◽  
2021 ◽  
Author(s):  
Jessie L Williamson ◽  
Christopher C Witt
Keyword(s):  
Partial Pressure ◽  
Bird Species ◽  
Seasonal Migration ◽  
Critical Examination ◽  
Niche Shift ◽  
Migratory Connectivity ◽  
Migratory Species ◽  
Arterial Blood ◽  
Air Density ◽  
Elevational Migration

Abstract Elevational migration can be defined as roundtrip seasonal movement that involves upward and downward shifts in elevation. These shifts incur physiological challenges that are proportional to the degree of elevational change. Larger shifts in elevation correspond to larger shifts in partial pressure of oxygen, air density, temperature, and ultraviolet (UV) exposure. Although most avian examples of elevational migration involve subtle shifts that would have minimal impacts on physiology, shifts of any magnitude have previously been considered under the broad umbrella of “elevational migration”. Here, we consider extreme seasonal elevational movements (≥2,000 m), sufficient to shift the elevational dimension of the eco-climatic niche. Migratory bird populations typically maintain inter-seasonal stability in the temperature, precipitation, and elevational aspects of their climatic niches, a tendency that likely reflects genetic physiological specialization on environmental conditions such as atmospheric pressure. A shift of ≥2,000 m involves a ≥20% change in air density and oxygen partial pressure, sufficient to incur functionally impactful declines in arterial blood-oxygen saturation and require compensatory shifts in respiratory physiology. We refer to this phenomenon as elevational niche-shift migration (ENSM). In this review, we analyzed >4 million occurrence records to identify 105 populations, representing 92 bird species, that undergo complete or partial ENSM. We identified key ecological and evolutionary questions regarding the causes and consequences of ENSM. Our synthesis reveals that ENSM has evolved independently in at least 29 avian families spanning 10 orders. Nonetheless, ENSM is rare relative to other forms of seasonal migration, consistent with the general tendency of seasonal niche conservatism by migratory species and evolutionarily conserved elevational range limits. For many migratory species and populations, within-species patterns of migratory connectivity are not sufficiently understood to determine ENSM status. ENSM is distinguished by its scale within the broader phenomenon of elevational migration. Critical examination of ENSM illustrates fundamental constraints on the ecology and evolution of migration systems, topographical influences on geographic patterns of migratory connectivity, and the remarkable metabolic flexibility of certain bird species that allows them to occupy disparate elevations across different seasons.

Slow and Fast Light in Plasma Using Optical Wave Mixing

2021 ◽  
Vol 126 (20) ◽  
Author(s):  
C. Goyon ◽  
M. R. Edwards ◽  
T. Chapman ◽  
L. Divol ◽  
N. Lemos ◽  
...  
Keyword(s):  
Wave Mixing ◽  
Optical Wave ◽  
Fast Light ◽  
Slow And Fast Light

scholarly journals AIR PRESSURE CONTROLLED MASS MEASUREMENT SYSTEM

2013 ◽  
Vol 24 ◽  
pp. 1360002
Author(s):  
RUILIN ZHONG ◽  
JIAN WANG ◽  
CHANGQING CAI ◽  
HONG YAO ◽  
JIN'AN DING ◽  
...  
Keyword(s):  
Measurement System ◽  
Pressure Range ◽  
Mass Measurement ◽  
Air Pressure ◽  
Air Density ◽  
Airtight Chamber ◽  
And Control ◽  
Automatic Mass ◽  
Pressure Controlled ◽  
Control Part

Mass measurement is influenced by air pressure, temperature, humidity and other facts. In order to reduce the influence, mass laboratory of National Institute of Metrology, China has developed an air pressure controlled mass measurement system. In this system, an automatic mass comparator is installed in an airtight chamber. The Chamber is equipped with a pressure controller and associate valves, thus the air pressure can be changed and stabilized to the pre-set value, the preferred pressure range is from 200 hPa to 1100 hPa. In order to keep the environment inside the chamber stable, the display and control part of the mass comparator are moved outside the chamber, and connected to the mass comparator by feed-throughs. Also a lifting device is designed for this system which can easily lift up the upper part of the chamber, thus weights can be easily put inside the mass comparator. The whole system is put on a marble platform, and the temperature and humidity of the laboratory is very stable. The temperature, humidity, and carbon dioxide content inside the chamber are measured in real time and can be used to get air density. Mass measurement cycle from 1100 hPa to 200 hPa and back to 1100 hPa shows the effective of the system.

Evanescent-Wave Interactions in an Optical Wave-Guiding Structure

1972 ◽  
Vol 11 (9) ◽  
pp. 1952 ◽  
Author(s):  
K. O. Hill ◽  
A. Watanabe ◽  
J. G. Chambers
Keyword(s):  
Evanescent Wave ◽  
Wave Interactions ◽  
Optical Wave

scholarly journals Light-induced levitation of ultralight carbon aerogels via temperature control

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reo Yanagi ◽  
Ren Takemoto ◽  
Kenta Ono ◽  
Tomonaga Ueno
Keyword(s):  
Carbon Nanotubes ◽  
Heat Capacity ◽  
Porous Materials ◽  
Temperature Control ◽  
Light Absorption ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Halogen Lamp ◽  
Absorption Properties ◽  
Air Density

AbstractWe demonstrate that ultralight carbon aerogels with skeletal densities lesser than the air density can levitate in air, based on Archimedes' principle, when heated with light. Porous materials, such as aerogels, facilitate the fabrication of materials with density less than that of air. However, their apparent density increases because of the air inside the materials, and therefore, they cannot levitate in air under normal conditions. Ultralight carbon aerogels, fabricated using carbon nanotubes, have excellent light absorption properties and can be quickly heated by a lamp owing to their small heat capacity. In this study, an ultralight carbon aerogel was heated with a halogen lamp and levitated in air by expanding the air inside as well as selectively reducing its density. We also show that the levitation of the ultralight carbon aerogel can be easily controlled by turning the lamp on and off. These findings are expected to be useful for various applications of aerogels, such as in communication and transportation through the sky.

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