Energy and propulsion optimization of solid-propellant grain of a hybrid power device

A method of distribution of an additional solid-phase component (oxidizer) providing uniformity of grain burning for the purpose of evaluation and optimization of energy and propulsion parameters of hybrid solid-propellant motor is proposed in the paper

Verification of model of calculation of intra-chamber parameters in hybrid solid-propellant rocket engines

On the basis of obtained analytical estimate of characteristics of hybrid solid-propellant rocket engine verification of earlier developed physical and mathematical model of processes in a hybrid solid-propellant rocket engine for quasi-steady-state flow regime was performed. Comparative analysis of calculated and analytical data indicated satisfactory comparability of simulation results

Morphology of ceramic particles produced by plasma-chemical synthesis

Thermal and diffusion processes in the droplet weakly concentrated metal salt solution during its heating in the plasma chemical reactor, in order to synthesize metal oxide powders are considered. Numerical study is based on previously proposed physical-mathematical model. The results of numerical calculations are analyzed to assess the possible influence of the operation parameters of the reactor and the characteristics of the initial solution (precursor) on the morphology of the particles formed

INTRASPECIES PTEROMYS-TALLENNUSTEN (SCIURIDAE, MAMMALIA) TALVEN TURKIVÄRJEN VÄRITTÄMINEN MALLISSA

Peer reviewe

ИССЛЕДОВАНИЕ ДИНАМИКИ ТЕРРИТОРИАЛЬНОГО РАСПРОСТРАНЕНИЯ И ЭКОЛОГИИ РЕДКИХ МЛЕКОПИТАЮЩИХ ТАЕЖНОЙ ЕВРАЗИИ (НА ПРИМЕРЕ ЛЕТЯГИ PTEROMYS VOLANS, RODENTIA, PTEROMYIDAE) in English INVESTIGATION OF THE DYNAMICS OF REGIONAL DISTRIBUTION AND ECOLOGY OF RARE MAMMALS TAIGA EURASIA (FOR EXAMPLE Letyago PTEROMYS VOLANS, RODENTIA, PTEROMYIDAE)

This study of the spatial distribution and ecology of the flying squirrel during the turn of the 20th century provides a description of new methods and techniques for detecting and accounting flying squirrels in the forest zone of Eurasia. The flying squirrel population area covers the territory of 61 regions of Russia, including Kamchatsky Krai and Chukotka Autonomous District. The number of flying squirrels in Karelia especially to the east – in the Arkhangelsk region and Western Siberia – significantly exceeds that of Finland, but considerable spatial variability in the number is obvious through all the regions: there are areas where this animal is quite abundant, or inhabits all the territory rather evenly, and there are areas where it is completely absent in vast territories even with seemingly favourable conditions. The flying squirrel is quite difficult to study and the reasons of its absence in obviously favourable areas are still to be explained. Some reasons are: the specificity of favourable landscape, forest coverage pattern, trophic relationships with predators and genetic aspect. A number of hypotheses are supposed to be tested in the nearest future. Key words: accounting, flying squirrel, forest zone, home range, spatial distribution.Peer reviewe

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

Energy and propulsion optimization of solid-propellant grain of a hybrid power device

A method of distribution of an additional solid-phase component (oxidizer) providing uniformity of grain burning for the purpose of evaluation and optimization of energy and propulsion parameters of hybrid solid-propellant motor is proposed in the paper

Double Continuum Model of Evolution of Precursor Droplets in the Flow of Heat Transfer Medium of a Plasma Chemical Reactor

A double continuum physical and mathematical model of evolution of precursor in a vaporizing droplet of low-concentration solution of metal salt in the process of its heating in the flow of heat transfer medium of a plasma chemical reactor is represented in this paper. This model was developed to study the morphology of ceramic powder particles depending on solution characteristics and parameters of a high-temperature gaseous heat transfer medium which determine heat and mass transfer with a droplet medium

Double Continuum Model of Evolution of Precursor Droplets in the Flow of Heat Transfer Medium of a Plasma Chemical Reactor

A double continuum physical and mathematical model of evolution of precursor in a vaporizing droplet of low-concentration solution of metal salt in the process of its heating in the flow of heat transfer medium of a plasma chemical reactor is represented in this paper. This model was developed to study the morphology of ceramic powder particles depending on solution characteristics and parameters of a high-temperature gaseous heat transfer medium which determine heat and mass transfer with a droplet medium

The mutual influence of nanometal additives on heat release rate in energetic condence system

The TG-DSC investigation of the mixture energetic polymer MPVT and metal nanopowders has been conducted. The investigation conducted have established a dependency of the metal oxidation rate in MPVT polymer matrix on its chemical nature. Aluminum oxidation was established to be promoted by addition transition metals, which can be a means to control the process of explosion and combustion of ECS