Simulation of the impact of the atmospheric weather state on the efficiency of functioning of solar thermal and power plants

THE PURPOSE. Determine the impact of the meteorological state of the atmosphere on the efficiency of the functioning of solar thermal and power plants. Modeling the molecular absorption of solar radiation by the atmosphere. Modeling the optical characteristics of the gaseous components of the atmosphere, atmospheric aerosol and clouds.METHODS. A method for numerical modeling of incoming solar radiation fluxes their functioning to determine the efficiency of solar thermal and power plants. The solar fluxes are calculated by stacking layers in a multi-stream approximation, taking into account the multi-tiered cloud cover and the probability of overlapping the sky with clouds. The absorption of radiation by the gaseous phase of the atmosphere is taken into account by the method of equivalent mass in an inhomogeneous atmosphere. The optical characteristics of the dispersed phase of the atmosphere are calculated using the Mie theory.RESULTS. An electronic database has been created on the optical characteristics of the gaseous components of the atmosphere, the optical characteristics of atmospheric aerosol and clouds. The effect of anthropogenic impact on the flux of solar radiation falling on the underlying surface is taken into account. The developed modeling takes into account the effect of humidity on the optical characteristics of atmospheric aerosol and its multicomponent composition, depending on the location of the power plant.CONCLUSION. The information necessary for numerical modeling of meteorological effects on the functioning of solar thermal and power plants is generalized. When calculating solar radiation fluxes, direct illumination of the light-receiving surface by solar radiation, scattered radiation by atmospheric aerosol and clouds are taken into account.

Visualization of the gas flows that formed above the thin-film coatings under VUV radiation influence

The plasma focus of a magnetoplasma compressor is a unique source of high-brightness broadband VUV (with photon energy of 5 to 100 electron volt) radiation. When such radiation affects on the surfaces of materials, it is possible to generate rather complex gas-dynamic structures due to the evaporation of the material and ionization of its vapors. A separate task is to study the processes of a gas-dynamic response to the exposure of the specified radiation fluxes on the surface of interference antireflection and reflective multilayers, which are used in modern laser technology, high-power optoelectronics, etc. In this report, we used schlieren photography for studying the features of gas-dynamic structures that arise at irradiation of coatings. Radiation resistant (in the visible and near IR ranges) HfO2/SiO2 and ZrO2/SiO2 multilayer structures (with a total thickness of 140–3700 nanometers and a number of layers of from 2 to 24) were used as prototypes for testing their stability under the VUV exposure.

Microclimate Parameters Evaluation for Spaces with Windows of Different Thermal Protection

Radiation cold flows from the windows in the winter period play an important role in the formation of the room overall thermal microclimate. The compliance with the requirements of GOST 30494–2011 for the resulting temperature and the local asymmetry of the resulting temperature in the centre of the room, as well as the boundaries of its serviced area, is not subject to any verification during the expert examination of the building projects. The designers do not perform such a check due to the absence of a method for calculating the influence of the temperature of all surrounding surfaces on these indicators. The standards for reduced heat transfer resistances of windows in residential and commercial public buildings have recently been increased. However, for the buildings of medical and preventive, preschool educational, general education institutions, and boarding schools these standards have remained the same. In the proposed work, the problem of the indoor microclimate parameter assessment is solved by calculations using the example of a library reading room with higher thermal protection of the windows and a classroom of the art school, where the window thermal protection has remained the same, in the city of Irkutsk. The percentage of the facade glazing in both cases was 34.5 %. The calculations, which have been made for the coldest calculation period, showed that for windows with an increased heat transfer resistance, the heating devices of the water heating system neutralize the cooling effect of the window radiation fluxes. In the rooms with an air heating system, the optimal norms of the resulting temperature are not met. For various regions of Russia, provision should be made of larger studies as to the combinations of the window heat transfer resistance and the window size to follow the daylighting standards, when the norms of the resulting temperature and the asymmetry of the resulting temperature are not possible to be met.

Preconditioning, aerosols, and radiation control the temperature of glaciation in Amazonian clouds

Glaciation in clouds is a fundamental phenomenon in determining Earth’s radiation fluxes, sensible and latent heat budgets in the atmosphere, the water cycle, cloud development and lifetime. Nevertheless, the main mechanisms that govern the temperature of glaciation in clouds have not been fully identified. Here we present an analysis of 15 years (2000-2014) of satellite, sunphotometer, and reanalysis datasets over the Amazon. We find that the temperature of glaciation in convective clouds is controlled by preconditioning dynamics, natural and anthropic aerosols, and radiation. In a moist atmospheric column, prone to deep convection, increasing the amount of aerosols leads to a delay in the onset of glaciation, reducing the glaciation temperature. For a dry column, radiative extinction by biomass burning smoke leads to atmospheric stabilization and an increase in the glaciation temperature. Our results offer observational benchmarks that can help a more precise description of glaciation in convective cloud models.

Geometrical Assessment of Sunlit and Shaded Area of Urban Trees Based on Aligned Orthographic Views

To quantify the ecosystem services of trees in urban environments, it is necessary to assess received direct solar radiation of each tree. While the Sky View Factor (SVF) is suitable for assessing the total incoming short- and longwave radiation fluxes, its information is limited to specific points in space. For a spatial analysis, it is necessary to sample the area for SVF. A new geometrical method, Area View Factor (AVF), for the calculation of sunlit areas is proposed. AVF is the ratio of the unhidden, projected surface of an object to the whole projected surface of an object in a complex environment. Hereby, a virtual, orthographic camera is oriented in accordance to the sun’s position in the 3D model domain. The method is implemented in the microscale model SkyHelios, utilizing efficient rendering techniques to assess AVF of all urban trees in parallel. The method was applied to Rieselfeld in Freiburg, Germany. The assessed sunlit area is compared to the SVF at the top of each tree and solar altitude angle, revealing a strong relationship between sunlit areas to solar altitude angles. This study shows that AVF is an efficient methodology to assess received direct radiation of urban trees. Based on AVF, it is possible to identify urban areas with shaded and sunlit trees, but it can also be applied to other objects in complex environments. Therefore, AVF is applicable for urban architecture or energetic research questions.

Thermal radiation of extended particles with subwavelength transverse dimensions

The paper proposes a new method for calculating the integral and spectral radiation coeffi-cients of extended subwavelength particles (ESPs), which include micro and nanocylinders and parallelepipeds. Comparison of the results of calculations by the proposed method with the calculated and experimental data found in the literature is carried out. It is shown that with decrease in only the transverse dimensions of the ESP (from values much larger than λmax to values much smaller than max) from the radiation spectrum, which was originally de-scribed by Planck's law and contained modes with both polarization directed along the axis and with polarization directed perpendicular to the axis , modes with wavelengths exceeding λcutoff (λcutoff is the cutoff wavelength) and having polarization perpendicular to the longi-tudinal axis of the ESP will be gradually eliminated, while modes with wavelengths polarized along the ESP axis will always be present in the radiation spectrum of the ESP. When the transverse dimensions of the ESP become much less than λmax, then all modes with polariza-tion perpendicular to the axis will disappear from the emission spectrum of this ESP, and on-ly modes with longitudinal polarization will remain. This is a fundamental difference from the SPs considered earlier in [16, 17], where methods for calculating SPs as disks, spheres, cubes were proposed. All the proposed calculation methods use the formalism of the decom-position of radiation fluxes into spectral-spatial modes.

The Irradiation of Methyl Cyanide (CH3CN) Ice at 15 K with 200 keV

<p>Methyl cyanide (CH<sub>3</sub>CN) is the simplest of the organic nitriles found in space. It was first identified in the molecular clouds<strong>, </strong>Sagittarius Sgr A and Sgr B in 1971, through its emission lines in the vicinity of 2.7 mm from the <em>J</em> = 6 ® 5 transition. In 1974 it was also reported in comet Kohoutek. CH<sub>3</sub>CN, has since been detected in the Hale Bopp comet and, as of 2009, there are no less than 58 hot molecular core objects in which CH<sub>3</sub>CN had been found. Methyl cyanide has also been discovered beyond the Milky Way galaxy, in the NGC 253 galax, which lies in the local group of galaxies, some 10 million light-years from Earth<sup>[1]</sup>. It has also been detected in the interstellar medium (ISM) where it is thought to be made on the grain mantles.</p> <p>Upon irradiation of the Irradiation of methyl cyanide (CH<sub>3</sub>CN) ice at 15 K with 200 keV Protons, we observed several compounds. Although this experiment was conducted under different conditions than comparable ones carried out by other researchers (eg Hudson and Moore 2004; Hudson, Moore et al. 2008), similar results were obtained. The objectives were to determine which molecules would form upon irradiation of CH<sub>3</sub>CN ice. The astrophysical ice of CH<sub>3</sub>CN is present in the ISM, comets, solar bodies (<em>eg</em> Titan) and other galaxies. These places receive radiation fluxes from levels of only a few eV to in excess of MeV cm<sup>-2</sup> s<sup>-1</sup>, the result being that complex molecules are formed - <em>eg</em> HCN/CN<sup>-</sup>, HCCCN, H<sub>2</sub>C=C=NH and CH<sub>4</sub>. This experiment was carried out using 200 keV protons, and so replicated a particular radiation level similar to that present in space. It was discovered that, upon the irradiation of CH<sub>3</sub>CN under laboratory conditions, the same molecules as Hudson <em>et al </em>2004 were formed. These molecules may then play an important role in the wider astrobiological context. For instance, HCN is vital in the formation of nitrogenous compound.</p> <div><br /> <div> <p> </p> </div> </div> <p>Please insert your abstract HTML here.</p>

Development of Composite Scintillators Based on the LuAG: Pr Single Crystalline Films and LuAG:Sc Single Crystals

The scintillation properties of novel type of composite scintillator based on Lu3Al5O12:Pr (LuAG:Pr) single crystalline film (SCF) and LuAG:Sc substrate grown by the liquid-phase epitaxy method are considered in this work. The registration of α-particles and γ-quanta in such types of composites occurs by means of separation of the scintillation decay kinetics of SCF and crystal parts, respectively. Namely, under excitation by α-particles of 241Am (5.5 MeV) source and γ-quanta of 137Cs (662 keV) source, the large differences in the respective scintillation decay kinetics and decay time values tα and tγ are observed for the LuAG:Pr SCF/LuAG:Sc SC composite scintillator with various film thicknesses. Furthermore, the best tγ/tα ratio above 4.5 is achieved for such types of epitaxial structure with SCF and substrate thicknesses of 17 μm and about 0.5 mm, respectively. The development types of composite scintillators can be successfully applied for simultaneous registration of α-particles and γ-quanta in the mixed radiation fluxes.