Utilization of Earth remote-sensing data to solve scientific and engineering problems within such fields as meteorology and climatology requires precise radiometric calibration of space-borne instruments. High-accuracy calibration equipment in the thermal-IR wavelength range ought to be combined during calibration procedures with the simulation of environmental conditions for space orbit (high vacuum, medium background). For more than 35 years, VNIIOFI has developed and manufactured standard radiation sources in the form of precision blackbodies (BB) functioning within wide ranges of wavelengths and working temperatures. These BBs are the spectral radiance and irradiance calibration devices in the world's leading space research institutions, such as SDL (USA), DLR (Germany), Keldysh Space Center (Russia), RNIIKP/RISDE (Russia), NEC Toshiba Space Systems (Japan), etc. The paper contains a detailed description of low-temperature precision BBs developed at VNIIOFI. The characteristics of variable-temperature (100 K to 400 K) research-grade extended-area (up to 350 mm) BB models BB100-V1 and BB-80/350 are described (they are intended for radiometric calibrations by comparison with a primary standard source), as well as those that can be used as sources for high-accuracy IR calibration of space-borne and other systems not requiring a vacuum environment. The temperature nonuniformity and stability of these BBs are (0.05 to 0.1) K (cavity-type BB100-V1), and 0.1 % for the (1.5 to 15) µm wavelength region under cryo-vacuum conditions of a medium-background environment.
The All-Russian Research Institute for Optical and Physical Measurements is currently carrying out a project on developing an integrated system for measurement assurance of Earth observations. The system should provide ground calibration of instruments and their control during space-borne observations. Such tasks require appropriate measurement facilities as well as regulatory documentation. In this paper we discuss the newly created radiometric facility, traceable to SI standard, for precise calibration of instruments for Earth observations, the project on precise monitoring of the stability of the instrument's in-flight performance and the development of national regulatory documentation in harmony with the international document ‘Quality Assurance Framework for Earth Observation—QA4EO’.
It is recognized that Covid-19 is mainly transmitted by airborne droplets. It is especially dangerous to sneeze and cough the patient, when together with a jet of air, moving at a high speed (when sneezing up to 150 km/h), droplets of liquid containing viruses fly out. It is known that even with a loud conversation the patient can release up to 1000 drops in the air with particles of a new type of coronavirus, especially coughing and sneezing carrier of the virus. There is a lack of experimental data to create physical and numerical models describing these processes and calculate the concentration of aerosol particles. The paper proposes an installation to determine the distribution of velocities and deformations in the time of the aerosol cloud that occurs when coughing and sneezing, as well as preliminary results of the first cycle of experiments at this installation. Based on the results, recommendations are made to counter the spread of infection. The purpose of these studies is to determine the direction and speed of the cloud carrying the droplets with the virus, as well as the time of its passage past potential recipients. Based on these data, it will be possible to estimate the received dose of infection and the dependence of this dose on the distance between the source and the potential victim. The study does not claim to be complete, which can be achieved by studying large groups of subjects, but after its completion it can serve as a source material for close to reality digital models of infection transmission. The work also contains preliminary results of the first cycle of experiments at this facility. On the basis of the results obtained, practical recommendations are given to counteract the spread of infection.
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