The Sun as a system of elementary particles

No unusual observation of the Sun is described here. No new theory is proposed. The paper — based on known facts of solar physics — is a modest attempt to interpret the Sun as a selfgravitating system of about 10⁵⁷ nucleons and electrons. These elementary particles are endowed with strong, electromagnetic, weak and gravitational interactions. Origin of the Sun, its evolution, structure and physiology are consequences of the four interactions.     

Multiple discriminant analysis of the Drava River alluvial plain sediments

Three discriminant function models are raised and cross-compared in order to distinguish geochemical patterns characteristic for the Drava River floodplain sediments. Based on data representing total element concentrations in samples collected from alluvium (A), terrace (T), and unconsolidated bedrock (B) at the border of a floodplain, four element clusters emerged accounting for discrimination between the referred groups of sediments. The most prominent is contaminant/carbonate cluster characteristic for alluvium. The other two are: silicate cluster typical for unconsolidated geological substrate (Neogene sedimentary rocks); and naturally dispersed heavy metal cluster separating terrace from the former two groups. Models introducing depth intervals and single profiles as grouping criteria reveal identical sediment-heavy metal matrices. The second important issue of this paper is possibility of reclassification of samples originally assigned to one of the a priori defined groups of sediments, based on established geochemical pattern. The mapped geological units can be reconsidered by the post hoc assignments to a different group if geological border between alluvium and terrace or between terrace and bedrock can not be established geologically with absolute certainty.     

Allowed Quantity of Explosive Charge Depending on the Distance from the Blast

This paper analyses results of trial, construction and quarry blasting, carried out in sediment rock deposits, mainly limestone and dolomite. Based on results of seismic measurements and engineering geological observations in sedimentary formation, an empirical relationship was established between ground vibration and geological strength index (GSI). The charge weight of explosive that may be detonated per delay for any given distance of nearby structures from the blast is approximately determined by using the concept of the scaled distance (SD) along with the DIN 4150 standard.     

Assessment of the natural and anthropogenic sources of chemical elements in alluvial soils from the Drava River using multivariate statistical methods

The objectives of this study are as follows: (a) an assessment of the geochemical background signature of the Drava Valley before the industrial revolution; (b) an evaluation of anthropogenic geochemical influences on the alluvial plains and river terraces in the valley; and (c) a determination of the spatial distribution of trace elements in the alluvial soils of the Drava River downstream of the Austrian–Slovenian border to the confluence of Mura and Drava Rivers.     

Azimuthal anisotropy of the Pg-wave velocity in hypocentral volumes of NW Croatia

Based on a large set of arrival times of the Pg phase reported by local and regional stations, we estimate azimuthal anisotropy of the Pg-wave velocity in focal volumes of the upper crust in NW Croatia. The method is based on analyses of the azimuthal dependence of ratios of cumulative differences of arrival times and travel paths between foci of earthquake pairs, computed for rays propagating within narrow azimuthal windows. The results clearly indicate the presence of anisotropy of 3.3% with the direction of fast velocity (approximately NNE-SSW) coinciding with the direction of the maximum tectonic pressure as revealed by 23 available focal mechanisms and previous geological investigations. Although a large part of observed anisotropy can be explained assuming that focal volumes are pervaded by a system of vertical extensive-dilatancy anisotropy (EDA) cracks aligned under the influence of local tectonic stress field, there is indication that — to a smaller extent — some role was also played by alignment of structural features in the region.     

Influence of sea-water intrusion and agricultural production on the Blato Aquifer,Island of Korčula,Croatia

The Blato aquifer is situated on the western side of the island of Korčula, southern Dalmatia, Croatia. The terrain is built of karstified carbonate rocks, mostly of the Cretaceous age. In the Blatsko karst polje there are four water supply wells with a total yield of about 60 l/s. The catchment area is 28 km². The whole terrain is tectonically disturbed and compressed; the most permeable fracture system is perpendicular to the structural “b” axes, which gives rise to a general groundwater direction towards the island’s northern coast. Average precipitation is 850 mm/year, but when there is less than 700 mm/year there is a high possibility of sea-water intrusion during the summer season. The risk significantly increases when dry years repeat. Hydrochemical research has shown that two main pollution sources occur at different hydrological moments: sea-water intrusion happens in the dry summer period when there is maximal extraction and almost no recharge; and the washing of nitrates and other humanly caused pollution indicators from the soil and epikarst belt during the rainy season. All factors must be taken into account when planning management and protection of such a sensitive environment.