New variable stars from the photographic archive: semi-automated discoveries,attempts at automatic classification and the new field 104 Her

Using 172 plates taken with the 40-cm astrograph of the Sternberg Astronomical Institute(Lomonosov Moscow University) in 1976–1994 and digitized with a resolution of 2400 dpi, we discovered and studied 275 new variable stars. We present the list of our new variables with all necessary information concerning their brightness variations. As in our earlier studies, the new discoveries show a rather large number of high-amplitude Delta Scuti variables, predicting that many stars of this type remain not detected in the whole sky. We also performed automated classification of the newly discovered variable stars based on the Random Forest algorithm. The results of the automated classification were compared to traditional classification and showed that automated classification was possible even with noisy photographic data. However, further improvement of automated techniques is needed, which is especially important when considering the very large numbers of new discoveries expected from all-sky surveys.     

Lagrangian modelling of multi-dimensional advection-diffusion with space-varying diffusivities: theory and idealized test cases

To efficiently simulate the advection-diffusion processes along and across density surfaces, we need to deal with a diffusivity tensor containing off-diagonal elements (Redi, J Phys Oceanogr, 12:1154–1158, 1982). In the present paper, the Lagrangian model, in case of a space-varying diffusivity tensor, is developed. This random walk model is applied for two idealized test cases for which the analytical solutions are known. Results of the testing show that the Lagrangian approach provides accurate and effective solutions of advection-diffusion problems for general diffusivity tensor.     

Correction to: Zeolite containing rocks of kudurs and reasons of geophagy within the territory of Sikhote-Alin Nature Zapovednik,Far East of Russia

This paper establishes a mechanical model of the stress distribution in front of the driving face during coal roadway excavation. Theoretical research shows that the stress state in the plastic zone of the driving face is consistent with the limit equilibrium equation, and the elastic zone is in accordance with the equilibrium equation based on elasticity mechanics. Based on this improved mechanical state solution model, different coal material constitutive hypotheses are used for the analysis. The width of the plastic zone calculated under the brittle-perfectly elastic model can reach 2–5 times the height of the roadway, and the stress concentration coefficient can reach two or more times. 3DEC numerical simulation software was used to simulate the stress distribution of the heading face. The results of the simulation are similar to those of the theoretical analysis. Compared with the elastic-perfectly plastic model, the calculated results of the brittle-perfectly elastic model are more consistent with the numerical simulation results. The heading face coal during roadway excavation shows obvious damage, and the strength characteristics of the coal decrease.     

Automated derivation and spatio-temporal analysis of landslide properties in southern Kyrgyzstan

The study area located in southern Kyrgyzstan is affected by high and ongoing landslide activity. To characterize this activity, a multi-temporal landslide inventory containing over 2800 landslide polygons was generated from multiple data sources. The latter include the results of automated landslide detection from multi-temporal satellite imagery. The polygonal representation of the landslides allows for characterization of the landslide geometry and determination of further landslide attributes in a way that accounts for the diversity of conditions within the landslide, e.g., at the landslide main scarp opposed to its toe. To perform such analyses, a methodology for efficient geographic information system (GIS)-based attribute derivation was developed, which includes both standard and customized GIS tools. We derived a number of landslide attributes, including area, length, compactness, slope, aspect, distance to stream and geology. The distributions of these attributes were analyzed to obtain a better understanding of landslide properties in the study area as a preliminary step for probabilistic landslide hazard assessment. The obtained spatial and temporal attribute variations were linked to differences in the environmental characteristics within the study area, in which the geological setting proved to be the most important differentiating factor. Moreover, a significant influence of the different data sources on the distribution of the landslide attribute values was found, indicating the importance of a critical evaluation of the landslide data to be used in landslide hazard assessments.