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An analytical investigation has been conducted on the steady-state conduction and a diluted gas exposed to a thermal radiation field experiences radiative heat transfer. Analytical solutions have been derived for the transport Boltzmann BGK partial differential equations system. The investigation delves into the irreversible thermodynamic behavior of the system through the utilization of the Liu-Lees model, which employs two-stream Maxwellian distribution functions. The moment approach is utilized to predict the behavior of macroscopic gas parameters like temperature, concentration, and Fourier heat flux. This process entails substituting these parameters into the two-stream Maxwellian distribution functions to analyze the system's non-equilibrium thermodynamic characteristics, which encompass gas particles and the heated plate. Through this analysis, kinetic coefficients, entropy, entropy flux, entropy production, and thermodynamic forces are determined. The investigation assesses the validation of Onsager's reciprocity relation, the Boltzmann H-theorem, the Le Chatelier principle, and the second law of thermodynamics within the system. Furthermore, the Gibbs formula is employed to estimate the ratios between various contributions to internal energy changes, which are determined by the total derivatives of extensive parameters. The non-equilibrium velocity distribution function was calculated for the first time, and its behavior was compared with that of the equilibrium one using 3D graphics. The behavior of the computed variables is predicted through graphical analysis and discussion of the results.

The analysis of the thermal effect of laser radiation on the sensory effect of the three-layer structure "prism—absorbing nanolayer—water" was resumed. The influence of the laser radiation flux on the metal nanolayer can lead to its significant heating and to the same heating of the adjacent water layers. In our previous studies, the approximation of the infinite absorption coefficient of the sensor nanolayer was considered by the example of gold. We investigated the effect of the finite absorption coefficient both on the heating of the sensory system in the sensor "prism—absorbing nanolayer—water" and on the change of the plasmon resonance wavelength in it. It was defined that with a decrease in the absorption coefficient k, the radiation flux required to achieve the same temperature as at k = ∞ increases. That is, to achieve the maximum sensory effect with a decrease in the absorption coefficient of the material, an increase in the flux is required. This makes the use of highly absorbing materials preferable. The range of radiation flux, at which the influence of temperature on the sensory effect can still be neglected, as before, does not exceed 1 W/cm2 in all studied cases. The magnitude of the sensory effect on the plasmon resonance wavelength also does not change in all studied cases and is 0.75% of the initial value of the plasmon resonance wavelength. [ABSTRACT FROM AUTHOR]

The evolution of atmospheric and Earth surface physical properties over a period of 15 years (based on data from the longer period from 2004 to 2022) is analyzed through the radiance fluxes measured by the Meteosat second generation (MSG) satellite series. The results show significant changes in the solar (−2.6% to −1.2%) and infrared (+0.4% to +1.0%) domains, with −3.9% for the CO2 absorption band (near 13.4 µm), all variations consistent with results from similar studies of radiation fluxes. Whereas the variation at 13.4 μm radiation is explained by the increase in the CO2 concentration in the atmosphere, the flux increase towards the satellite in the remainder of the infrared spectra measured by MSG corresponds to surface warming (as documented in external sources like the IPCC, the Intergovernmental Panel on Climate Change). The solar outgoing flux decrease exposes a recent reduction in the Earth's cloud cover under the nominal field of view of Meteosat at 0 degrees longitude (MFOV). Radiance evolution at 6.2 µm and 7.3 µm, a spectral region of intense absorption by water vapor, is interpreted in terms of sensitivity to the humidity content in the middle and upper troposphere by means of a simple radiation transfer model. [ABSTRACT FROM AUTHOR]

Energy flux of Vertical Greening System (VGS) is crucial for understanding of heat exchange processes by optimizing the cooling performance in outdoor thermal comfort, thereby mitigating heat stress through the transpiration. To understand the potential cooling effect of VGS, we quantify the Mean Radiant Temperature (MRT) of VGS by analyzing radiation flux and evaluating cooling efficiency, defined as the ratio of the cooling effect provided by the VGS to the energy input necessary to achieve that effect to quantify the effectiveness of VGS. The VGS showed a decrease in net radiation by 120 W/ m2, resulting in a decline in MRT by 3.02 °C compared to the wall. Furthermore, we found that the cooling efficiency of transpiration in VGS was 7.38 times more effective than evaporation from soil without plants. These findings suggest that VGS has the potential to significantly reduce heat stress and serve as an efficient strategy in urban areas.

Large-scale traffic accidents caused by black ice on roads have increased rapidly; hence, there is an urgent need to prepare safety measures for their prevention. Here, we used local weather road observations and the linkage between weather prediction and a radiation flux model (LDAPS-SOLWEIG) to calculate prediction information regarding habitual shade areas, sky view factor (SVF), and downward shortwave radiative flux by road direction and lane. Using the LDAPS-SOLWEIG model system, a set of real-time weather prediction data (temperature, humidity, wind speed, and insolation at 1.5 km resolution) was applied, and 5 m resolution radiative flux prediction data, with road resolution blocked by local weather and topography, were calculated. We found that the habitual shaded area can be divided by the direction and lane of the road according to the height and shape of the terrain around the road. The downward shortwave radiation flux data from local meteorological observation data and that calculated from the LDAPS-SOLWEIG model system were compared. When road-freezing occurred on a case day, the RMSE was 20.41 W·m−2, MB was −5.04 W·m−2, and r was 0.78. The calculated information, habitual shaded area, and SVF can highlight road sections vulnerable to winter freezing and can be helpful in the special management of these areas. [ABSTRACT FROM AUTHOR]

The evolution of atmospheric and Earth surface physical properties over a period of 15 years (based on data from the longer period from 2004 to 2022) is analyzed through the radiance fluxes measured by the Meteosat second generation (MSG) satellite series. The results show significant changes in the solar (−2.6% to −1.2%) and infrared (+0.4% to +1.0%) domains, with −3.9% for the CO2 absorption band (near 13.4 µm), all variations consistent with results from similar studies of radiation fluxes. Whereas the variation at 13.4 μm radiation is explained by the increase in the CO2 concentration in the atmosphere, the flux increase towards the satellite in the remainder of the infrared spectra measured by MSG corresponds to surface warming (as documented in external sources like the IPCC, the Intergovernmental Panel on Climate Change). The solar outgoing flux decrease exposes a recent reduction in the Earth’s cloud cover under the nominal field of view of Meteosat at 0 degrees longitude (MFOV). Radiance evolution at 6.2 µm and 7.3 µm, a spectral region of intense absorption by water vapor, is interpreted in terms of sensitivity to the humidity content in the middle and upper troposphere by means of a simple radiation transfer model.

Solar photovoltaic (PV) performance is affected by increased panel temperature. Maintaining an optimal PV panel temperature is essential for sustaining performance and maximizing the productive life of solar PV panels. Current temperature sensors possess a long response time and low resolution and accuracy. Advanced fibre-optic sensors offer distinct advantages of greater accuracy, a more comprehensive range, and a very high sampling rate. The present experimental work focuses on fibre Bragg grating sensor-based solar PV panel temperature monitoring. The unique capabilities of fibre-optic sensors are demonstrated by studying the rapid perturbations in panel temperature over time for indoor and outdoor conditions. The effects of incident radiation flux and the inclination angle on panel temperature are analyzed. Temperature sensitivity of 6 pm/°C is obtained. The results are helpful in dynamic monitoring of panel temperature, understanding the thermal interactions at the microscale level, and streamlining the measured temperature of multiple panels on solar farms. Thus, the proposed advanced method of FBG-based temperature monitoring of solar panels could be helpful to operate an integrated cooling system to improve the performance of solar panels.

The Nordic Seas have a significant impact on the climate system. Here 23-day air-sea heat fluxes were analyzed from an in situ air-sea coupled buoy deployed in the Lofoten Basin from 5 August 2012 to 27 August 2012. The buoy captured two stages of strong south and north winds. The observations indicate that warm and wet air transported by the south wind can lead to decreased sensible and latent heat fluxes and net longwave radiation. The total oceanic heat loss was 50–60 W m−2. Thus, this stage was called the heat insulation process. By contrast, the heat dissipation process occurred with the north wind condition during advection of the cold and dry air. During this process, sensible and latent heat fluxes and net longwave radiation notably increased. The total oceanic heat loss during the heat dissipation process reached 240 W m−2, which was four-fold greater than that in the heat insulation process. Given that the heat insulation process is dominant in summertime, the ocean lost minimal heat but absorbed strong solar energy. Thus, a large quantity of energy was stored in the ocean. Heat was transported to the Arctic Ocean and accelerated Arctic warming. The heat dissipation process is dominant in autumn and winter when the ocean releases considerably more energy. The two processes revealed in this paper can be applied to warm-water areas in high latitudes. [ABSTRACT FROM AUTHOR]

Large-scale traffic accidents caused by black ice on roads have increased rapidly; hence, there is an urgent need to prepare safety measures for their prevention. Here, we used local weather road observations and the linkage between weather prediction and a radiation flux model (LDAPS-SOLWEIG) to calculate prediction information regarding habitual shade areas, sky view factor (SVF), and downward shortwave radiative flux by road direction and lane. Using the LDAPS-SOLWEIG model system, a set of real-time weather prediction data (temperature, humidity, wind speed, and insolation at 1.5 km resolution) was applied, and 5 m resolution radiative flux prediction data, with road resolution blocked by local weather and topography, were calculated. We found that the habitual shaded area can be divided by the direction and lane of the road according to the height and shape of the terrain around the road. The downward shortwave radiation flux data from local meteorological observation data and that calculated from the LDAPS-SOLWEIG model system were compared. When road-freezing occurred on a case day, the RMSE was 20.41 W·m−2, MB was −5.04 W·m−2, and r was 0.78. The calculated information, habitual shaded area, and SVF can highlight road sections vulnerable to winter freezing and can be helpful in the special management of these areas.

Irradiation of a thermonuclear capsule by a laser-induced X-ray pulse (indirect drive) is a way to maximally reduce the inhomogeneity of the capsule heating and, thereby, to minimize the negative influence of hydrodynamic instabilities on its compression. Nevertheless, the application of this method in the world's largest NIF facility with a laser pulse energy of about 1.8 MJ at the Lawrence Livermore National Laboratory (LLNL), USA has not yet provided the ignition of indirect-drive thermonuclear capsule – obtaining of the deuterium–tritium reaction energy equal to the spent laser energy. We devote this paper to the theoretical study of compression and burning of thermonuclear capsule with different degrees of violation of its heating uniformity by laser-induced X-ray pulse within the framework of further development of the indirect-drive approach. [ABSTRACT FROM AUTHOR]

In line with the energy development strategy of Europe, it is necessary to implement energy efficient buildings, in which the external enclosures are converters of solar energy to thermal. Therefore, the purpose of the publication was the scientific substantiation and development of the solar heating system with the use of rooftop solar panels. Graphical and analytical dependences of the coefficient of thermal efficiency of the solar panel in heat supply system from the angles of solar radiation incoming and the density of the radiation flux were obtained. Analysis of the results showed that the coefficient of thermal efficiency of the solar panel without transparent coating with the placement of pipelines of the circulation circuit of the coolant over the heat absorber increases by 50%. [ABSTRACT FROM AUTHOR]

Concerning the issues regarding driving mileage reduction for electric vehicles (EVs) in cold climates, a heat pump system with low global warming potential refrigerant R290/R1234yf is employed as one of the promising solutions. Different from the widely used mobile refrigerant R134a, R290 and R1234yf are both flammable or explosive. The application of R290/R1234yf in the mobile heat pump system is hindered by unexpected refrigerant leakage with the existence of fire and explosion risk. In this study, the combustion characteristics of R290/R1234yf in a potential leakage process from an air-conditioning heat pump system for EVs were investigated. Firstly, thermodynamic behaviours of R290/R1234yf used in a typical heat pump system were analysed based on a special experimental facility designed for EVs. Then the leakage and combustion characteristics of R290/R1234yf including flame shape, temperature, radiation etc. were obtained by the experimental method under different initial temperature and mass flow rate conditions. It was found that R290/R1234yf leaked is difficult to ignite at low temperatures, while the blow-off phenomenon of the jet flame would occur at high temperature with high leakage mass flow rate. In addition, the results showed that combustion intensity would be enhanced by the leakage mass flow rate between 30 and 60°C. These results could provide guidance for fire detection and rescue system design for new energy vehicles.

The main purpose of this article is to investigate three-dimensional steady rotating flow of rate type fluid (Maxwell fluid) over an exponential stretching surface. The Maxwell fluid saturates the porous space via Darcy–Forchheimer relation. Flow caused by the exponential stretchable surface of sheet. Chemical reaction along with Arrhenius energy is considered at the surface. Energy expression is modeled subject to heat source/sink and radiation flux. Appropriate transformations leads to ordinary ones. Homotopy method is implemented for the series solutions. Pertinent parameters are discussed graphically. Special consideration is given to the engineering quantities such as Sherwood and Nusselt numbers and discussed numerically through tabular form. Temperature distribution enhances versus higher radiation and heat source/sink parameter while decays for larger Prandtl number. Furthermore, velocity shows decreasing trend through larger porosity and Deborah number. [ABSTRACT FROM AUTHOR]