scholarly journals Quasilocal energy exchange and the null cone

2016 ◽  
Vol 94 (8) ◽  
Author(s):  
Nezihe Uzun
Keyword(s):  
Energy Exchange ◽  
Null Cone ◽  
Quasilocal Energy

Systematization of Shock Response Control Based on Momentum Exchange and Energy Exchange and Its Application to Lunar/Planetary Spacecraft

Impact ◽  
2019 ◽  
Vol 2019 (10) ◽  
pp. 73-75
Author(s):  
Susumu Hara
Keyword(s):  
Energy Exchange ◽  
Control Mechanism ◽  
Cost Effective ◽  
Aerospace Engineering ◽  
Single Test ◽  
Momentum Exchange ◽  
Mars Rover ◽  
Response Control ◽  
Shock Control ◽  
Shock Response

Professor Susumu Hara is based at the Department of Aerospace Engineering, Nagoya University in Japan explains that when the Mars rover Opportunity was set to land on that planet in the first weeks of 2004, onlookers held their breath as it dropped from orbit and hurtled toward the red surface. 'Any failure in the calculations or landing systems would mean a harder than expected impact,' he highlights. 'The impacts sustained by a rover such as Opportunity can derail a mission before it even starts, damaging cargo or vital systems required to complete the mission.' Impacts occur during landing but also as the craft enters the atmosphere, when it makes sudden moves, while it is on surface or when debris strikes it. 'Therefore, a system and materials to protect a craft are vital,' outlines Hara. 'Surprisingly, the solutions to this problem are not sophisticated. In fact, most craft still employ devices resembling automobile bumpers, which absorb the energy from an impact by crumpling under the force of said impact.' Unfortunately, these cannot be reused, even during testing phases a new prototype is required after every single test run. Recent missions also employed techniques like airbags or sky cranes. While successful they too have drawbacks. 'Airbags create huge rebounds which can jostle the craft and the contents inside while sky cranes are extremely costly to develop,' Hara says. For this reason, he is dedicated to designing a new highly reliable and cost-effective shock control mechanism.

SIMPLE DEMONSTRATIONS OF THE ENERGY EXCHANGE BETWEEN SYSTEM AND ITS SURROUNDING

2001 ◽  
Vol 2 (3) ◽  
pp. 329-332
Author(s):  
Dragica ŠIŠŠOVIĆ ◽  
Nikola ŠIŠŠOVIĆ
Keyword(s):  
Energy Exchange

scholarly journals Energy exchange during third harmonic generation in multi-mode optical fibers

2021 ◽  
Vol 1859 (1) ◽  
pp. 012050
Author(s):  
Z Kasapeteva ◽  
A Dakova ◽  
V Slavchev ◽  
D Dakova ◽  
L Kovachev ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Harmonic Generation ◽  
Energy Exchange ◽  
Third Harmonic Generation ◽  
Third Harmonic ◽  
Multi Mode

scholarly journals Improving the Evapotranspiration Estimation under Cloudy Condition by Extending the Ts-VI Triangle Model

2021 ◽  
Vol 13 (8) ◽  
pp. 1516
Author(s):  
Boyang Li ◽  
Yaokui Cui ◽  
Xiaozhuang Geng ◽  
Huan Li
Keyword(s):  
Remote Sensing ◽  
Surface Temperature ◽  
Land Surface ◽  
Energy Exchange ◽  
Vegetation Index ◽  
Regional Scale ◽  
Reconstruction Algorithm ◽  
Heihe River ◽  
Main Process ◽  
In Situ Data

Evapotranspiration (ET) of soil-vegetation system is the main process of the water and energy exchange between the atmosphere and the land surface. Spatio-temporal continuous ET is vitally important to agriculture and ecological applications. Surface temperature and vegetation index (Ts-VI) triangle ET model based on remote sensing land surface temperature (LST) is widely used to monitor the land surface ET. However, a large number of missing data caused by the presence of clouds always reduces the availability of the main parameter LST, thus making the remote sensing-based ET estimation unavailable. In this paper, a method to improve the availability of ET estimates from Ts-VI model is proposed. Firstly, continuous LST product of the time series is obtained using a reconstruction algorithm, and then, the reconstructed LST is applied to the estimate ET using the Ts-VI model. The validation in the Heihe River Basin from 2009 to 2011 showed that the availability of ET estimates is improved from 25 days per year (d/yr) to 141 d/yr. Compared with the in situ data, a very good performance of the estimated ET is found with RMSE 1.23 mm/day and R2 0.6257 at point scale and RMSE 0.32 mm/day and R2 0.8556 at regional scale. This will improve the understanding of the water and energy exchange between the atmosphere and the land surface, especially under cloudy conditions.

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