Modelling ice-divide dynamics by perturbation methods

Two-dimensional, isothermal, non-stationary, cold-glacier dynamics are analysed by perturbation methods, when the ice creep is described by Glen's flow law. This approach allows us to model the ice-divide dynamics separately from that of the glacier and to pose a simplified problem for the ice divide. To order of the glacier-aspect ratio, all unknown characteristics near the ice divide can be searched for in an infinite layer with parallel boundaries, whose thickness coincides with that found by the shallow-ice approximation. The problem for the ice divide is stationary and does not depend on the ice and glacier characteristics, such as a flow-law constant, ice thickness and accumulation rate. At the ice divide, the ice upper surface curvature is finite and the shallow-ice approximation is inadequate

Electronic Participation and Participatory Budgeting as Feedback Mechanisms in the Smart City Model

Participatory budgeting (PB) is considering in the article as a mechanism of citizens’ participation in budget policy at the local level. Based on the parameters of evaluating the effectiveness of participatory budgeting projects, the paper presents the preliminary results of the comprehensive study of e-participation institutional model, describing the feedback mechanism in the development and functioning of smart urban management systems (including e-governance). In this regard, the analysis of international PB projects’ evaluation methodologies, the study of the subject area, and the literature review on the subject of the study were conducted.As a result of the study, the initial version of the smart city institutional model was refined, containing elements of participatory budgeting and electronic participation as feedback components. A comparative analysis of international methodologies for PB projects’ assessment is carried out; conclusions are formulated; directions for further research are described.The subsequent analysis of PB projects’ evaluation methodologies will focus on the study of practices, based on the aspects of digital transformation and smart city development. Thus, the empirical results of this study can be used for the theoretical development of a new relevant methodology that takes into account the above described components

Features of periodic temperature profiles in filtrating capillary porous media

The behavior of temperature profiles is examined in filtrating capillary porous media which are subjected to periodic heating. Reasons are described for amplitude shift in the temperature oscillations versus the fluid filtration rate. © 1992 Plenum Publishing Corporation

Modelling of a marine glacier and ice-sheet-ice-shelf transition zone based on asymptotic analysis

All parts of a two-dimensional, isothermal, stationary marine glacier (grounded ice sheet, ice shelf and transition zone) with constant viscosity are analysed by perturbation methods. In so doing, all zones of different flow patterns can be considered separately. Correlations between spatial scales for all parts can be expressed in terms of the typical ice-surface slope distant from the ocean, which reflects exterior conditions of the glacier's existence. In considering the ice-sheet-ice-shelf transition zone, a small parameter characterizing the difference between ice and water densities is used. Such an analysis allows us to find boundary conditions at the grounding line for the grounded ice mass. Glacier-surface profiles are determined by numerical methods. The grounding-line position found by using the boundary conditions derived in this paper differs from that obtained by using Thomas and Bentley's (1978) boundary conditions by about 10% of the grounded ice-stream length

The possible evolution of pitch angles of spiral galaxies

The origin and maintenance of spiral structure in galaxies, the correlation between different types of spiral structure and several proposed mechanisms for their generation, and the evolution of spiral arms of galaxies with time are questions that are still controversial. In this note we study the spiral structure in a sample of distant galaxies in order to infer the evolution of spiral arm characteristics with redshift. We considered a sample of 171 face-on spiral galaxies in the Hubble Space Telescope COSMOS (The Cosmic Evolution Survey) field. The galaxies are distributed up to $z \approx 1$ with a mean value of 0.44. For all galaxies, we determined the pitch angles of the spiral arms and analysed their dependence on redshift; a total of 359 arms were measured. Analyses of our measurements combined with the literature data suggest a possible evolution of the pitch angles of spiral galaxies: by the modern epoch the spiral pattern, on average, becomes more tightly wound. This may be a consequence of the general evolution of the structure of galaxies as galaxies become more massive over time and their bulges grow. In addition, the distribution of the cotangent of pitch angle of galaxies indicates the possibility that the dominant mechanism of spiral pattern generation changes over time.Comment: 5 pages, accepted for publication on Astronomy & Astrophysics Letter

Anaerobic conversion of biomass upon disintegration in ultrasonic fields of low intensity

Disintegration is the destruction of the cell structure to release all its contents. This process facilitates bacteria access to nutrients and it results in a substrate decomposition rate increase. We can use thermal (the brief heating below one hundred degrees temperature at normal pressure or higher one hundred degrees temperature at enhanceable pressure) and chemical (enzymes and catalysts addition, which can positively influence the process speed), biochemical and physical-mechanical methods (the sonication). © 2014 WIT Press

UAV-based photogrammetry: Assessing the application potential and effectiveness for archaeological monitoring and surveying in the research on the ‘valley of the kings’ (Tuva, Russia)

The article offers an evaluation of the adequacy and effectiveness of using UAV-based photogrammetry for updating the planigraphy of well-studied archaeological sites and discovering new ones. The study is based on the data collected in the ‘Valley of the Kings’ in the Republic of Tyva (otherwise called Tuva, Russia). Data analysis using GIS software found 1000 archaeological objects and other, possibly archaeological objects. UAV-based digital photogrammetry has proved informative and effective in our study. In addition to the previously known archaeological objects, it enabled us to detect numerous new archaeological objects, which had been missed in the earlier investigations carried out on the ground. However, this survey technology has been found to have a significant number of limitations as to its applicability in the search for archaeological objects, and it is concluded that UAVs cannot replace archaeological investigations on the ground, particularly as regards identification of objects