Invariant Form of BK-factorization and its Applications

Invariant form of BK-factorization is presented, it is used for factorization of the LPDOs equivalent under gauge transformation and for construction of approximate factorization simplifying numerical simulsations with corresponding LPDEs of higher orderComment: 11 pages, 7 figure

Nonlinear acoustic waves in channels with variable cross sections

The point symmetry group is studied for the generalized Webster-type equation describing non-linear acoustic waves in lossy channels with variable cross sections. It is shown that, for certain types of cross section profiles, the admitted symmetry group is extended and the invariant solutions corresponding to these profiles are obtained. Approximate analytic solutions to the generalized Webster equation are derived for channels with smoothly varying cross sections and arbitrary initial conditions.Comment: Revtex4, 10 pages, 2 figure. This is an enlarged contribution to Acoustical Physics, 2012, v.58, No.3, p.269-276 with modest stylistic corrections introduced mainly in the Introduction and References. Several typos were also correcte

Formation and development of the system of public affairs institutes: governmental administrative aspect

The article states that formation and development of the public affairs institutes from the position of the state administration have to be dealt with as a polisystematic and polistructural result of intergration of many spheres of society viability maintenance with the following functionally related specific complexes: logistical, economic, social, domestic and cultural. The author proves that they are organizationally combined from the political and ideological position to create a certain sphere – the sphere of housing and municipal services that constitutes the system of structures contributing to the functioning of housing and utilities sector. It is defined that modernization of the housing and utilities sector provides for the complex of political, economic, research, educational, institutional and management, as well as technically preventative measures aimed at realization of citizens’ rights to civilized housing and utility conditions as the determining factor of reproduction of a human and society

Crisis management in theory of public administration

Main principles of strategic public administration in terms of crisis forming considered; especially attention focused on the aspect of the anti-crisis management effectiveness from point of view the necessity adopting of it for public administration and state regulation of economic

Quaternary palynostratigraphy of the Pechora Sea

By combining the lithologic, original palynologic and published micropaleonthological data we reconstructed paleogeographical events On the Pechora shelf during the Younger Dryas and Holocene time. Our paleoenvironmental reconstructions are based On the regularities in formation of pollen-and-spores assemblages in the surface sediments of the Pechora Sea. The main stages in paleogeography of the Pechora Sea during the Late Pleistocene were emphasized. The Late Valdai sediments in the Pechora Sea region were accumulated under the influence of fluvioglacial flows probably from the melting ice cap on Kolguev Island and, also, coastal glaciers. Climate deterioration considerably changed coastal vegetation as reflected in the depleted taxonomic and quantitative composition of palynospectra. The pollen data suggest that Open steppe-like plant communities with Artemisia, Poaceae, Asteraceae and Caryophyllaceae dominated dry ecotopes On watersheds, whereas tundra-like communities with Betula nana, arctic Salix, Dryas, Saxifraga, Carex and Brassicaceae were common in more humid coastal lowlands. The overlying silts and loamy sands are believed to have been accumulated during early deglaciation, i.e., Older Dryas and Alleröd. During this phase the glacial sedimentation was rather rapidly replaced by a glaciomarine deposition. Progressive climate warming caused prominent changes in coastal vegetation. Discontinuous treeless tundra-steppe associations were replaced by dwarf and shrub ernik tundra. A "complex vegetation cover" of forest-tundra apparently existed in the northern part of the Kola Peninsula and in the Northern Dvina Lowland. By the end of the Alleröd alder-bushes and horsetails occupied riverbanks, and spruce occurred in the forest-tundra communities on the adjacent hinterland

The Child Factor in Child–Robot Interaction: Discovering the Impact of Developmental Stage and Individual Characteristics

Social robots, owing to their embodied physical presence in human spaces and the ability to directly interact with the users and their environment, have a great potential to support children in various activities in education, healthcare and daily life. Child–Robot Interaction (CRI), as any domain involving children, inevitably faces the major challenge of designing generalized strategies to work with unique, turbulent and very diverse individuals. Addressing this challenging endeavor requires to combine the standpoint of the robot-centered perspective, i.e. what robots technically can and are best positioned to do, with that of the child-centered perspective, i.e. what children may gain from the robot and how the robot should act to best support them in reaching the goals of the interaction. This article aims to help researchers bridge the two perspectives and proposes to address the development of CRI scenarios with insights from child psychology and child development theories. To that end, we review the outcomes of the CRI studies, outline common trends and challenges, and identify two key factors from child psychology that impact child-robot interactions, especially in a long-term perspective: developmental stage and individual characteristics. For both of them we discuss prospective experiment designs which support building naturally engaging and sustainable interactions

Bottleneck crossover between classical and quantum superfluid turbulence

We consider superfluid turbulence near absolute zero of temperature generated by classical means, e.g., towed grid or rotation but not by counterflow. We argue that such turbulence consists of a polarized tangle of mutually interacting vortex filaments with quantized vorticity. For this system, we predict and describe a bottleneck accumulation of the energy spectrum at the classical-quantum crossover scale l. Demanding the same energy flux through scales, the value of the energy at the crossover scale should exceed the Kolmogorov-41 (K41) spectrum by a large factor ln10/3(l/a0) (l is the mean intervortex distance and a0 is the vortex core radius) for the classical and quantum spectra to be matched in value. One of the important consequences of the bottleneck is that it causes the mean vortex line density to be considerably higher than that based on K41 alone, and this should be taken into account in (re)interpretation of new (and old) experiments as well as in further theoretical studies

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

When one swings a short corrugated pipe segment around one’s head, it produces a musically interesting whistling sound. As a musical toy it is called a “Hummer” and as a musical instrument, the “Voice of the Dragon.” The fluid dynamics aspects of the instrument are addressed, corresponding to the sound generation mechanism. Velocity profile measurements reveal that the turbulent velocity profile developed in a corrugated pipe differs notably from the one of a smooth pipe. This velocity profile appears to have a crucial effect both on the non-dimensional whistling frequency (Strouhal number) and on the amplitude of the pressure fluctuations. Using a numerical model based on incompressible flow simulations and vortex sound theory, excellent predictions of the whistling Strouhal numbers are achieved. The model does not provide an accurate prediction of the amplitude. In the second part of the paper the sound radiation from a Hummer is discussed. The acoustic measurements obtained in a semi-anechoic chamber are compared with a theoretical radiation model. Globally the instrument behaves as a rotating (Leslie) horn. The effects of Doppler shift, wall reflections, bending of the tube, non-constant rotational speed on the observed frequency, and amplitude are discusse