Methane emissions reduce the radiative cooling effect of a subtropical estuarine mangrove wetland by half

2020 ◽  
Vol 26 (9) ◽  
pp. 4998-5016 ◽  
Author(s):  
Jiangong Liu ◽  
Yulun Zhou ◽  
Alex Valach ◽  
Robert Shortt ◽  
Kuno Kasak ◽  
...  
Keyword(s):  
Methane Emissions ◽  
Cooling Effect ◽  
Radiative Cooling ◽  
Mangrove Wetland

Thermal Radiative Cooling Enabled Freeze Tweezer for Manipulating Micro Scale Objects

2011 ◽  
Author(s):  
Yang Yang ◽  
Jing Liu
Keyword(s):  
Numerical Simulation ◽  
Small Volume ◽  
Freezing Behavior ◽  
Cooling Effect ◽  
Radiative Cooling ◽  
Convective Cooling ◽  
Micro Scale

A freeze tweezer is a new kind of manipulation tool which employs the freezing force of a small volume of nucleotide ice for operating the micro-objects in an aqueous state. Previously, such typical device prototypes were respectively realized based on conductive and convective cooling effect. Aiming to present an alternative feasible way for realizing the freeze tweezer in micro or even much smaller size by thermal radiative cooling, a complete 3-D numerical simulation on the operation behaviors of such kind freeze tweezer have been implemented. As a result, the droplet freezing behavior is directly caused by the freeze tweezer rather than the thermal radiative cooling from the sidewall. It indicates that this new freeze tweezer would also complete all the functions as its previous type would achieve.

scholarly journals Numerical calculation of passenger compartment cooling effect under the action of radiative cooling film based on MATLAB

2021 ◽  
Vol 2125 (1) ◽  
pp. 012027
Author(s):  
Yipeng Chao ◽  
Xin Luo ◽  
Chao Zheng ◽  
Yipeng Chao
Keyword(s):  
Ambient Temperature ◽  
Infrared Radiation ◽  
Simulation Models ◽  
Cooling Effect ◽  
Radiative Cooling ◽  
Passenger Compartment ◽  
Time Space ◽  
Cold Source ◽  
Radiation Material ◽  
Atmospheric Transmittance

Abstract Radiative cooling uses space cold source to cool the object, and the radiative cooling film made by using this principle can be applied to automobiles effectively to save the refrigeration resources of automobiles. However, due to the limitation of economy, time, space and other factors, it is difficult to carry out comprehensive research on the actual film-forming cooling effect. Based on the principle of passive radiative cooling, a set of simulation models is developed, which is applied to the selection of infrared radiation materials for automotive radiative cooling film and the study of the influence of environmental factors on the radiative cooling effect. SiO2 was finally selected as infrared radiation material. At the same time, the theoretical cooling temperature of the radiative cooling film applied to the passenger compartment of automobiles can reach 6.8°C under the conditions of 35°C ambient temperature, 0.99 atmospheric transmittance and 10 heat transfer coefficient, using SiO2 as infrared radiation material and PE as dispersion substrate. At the same time, the cooling effect of the radiative cooling film is positively correlated with the ambient temperature, atmospheric transmittance to some extent.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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