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Number of results: 6
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Abstract

The archipelago of Svalbard in the European High Arctic lies on the convergence of the Palaearctic and Nearctic flora and fauna and contains elements of both regions. The island of Hopen is located in the south east of the archipelago within the path of the cold south−westerly flowing East Svalbard Current originating in the Arctic ocean and flowing along the north Russian coast. This current is postulated as a colonization route of the invertebrate fauna of Svalbard. Few reports of the terrestrial invertebrates of Hopen exist and none of the mite suborders Oribatida or Mesostigmata. With the taxonomic confusion existing in the inventories of this important region of the Arctic, new sampling campaigns with species identified by modern taxonomic principles and with material deposited in accessible museums and collections are essential. Identified mites included six species of oribatid mites with Diapterobates notatus dominating, and five species of Mesostigmata with Zercon forsslundi forming the dominant species. None of the species collected was a new record for Svalbard and all have wide circumpolar, Palaearctic or Holarctic distributions. Dispersal to Svalbard from northern Russia is hence neither supported nor rejected. The expected oribatid and mesostigmatid diversity of the island is greater than observed from the limited sampling described here.
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Abstract

During the cruise of the research ship r/v Oceania owned by the Institute of Oceanology of the Polish Academy of Sciences in Sopot a research on mineral suspension concentration and dispersion distributions was conducted. The research area included the western part of the Baltic Sea, the Danish Straits, the Norwegian Sea, the waters around Spitsbergen and the North Atlantic Ocean. Samples of water were collected from the surface layer. They were subjected to microscopic analysis. Measurements were done with a projection microscope (magnification lOOOx) and using the Burker's table. After counting the particles dispersion distribution was determined. The largest concentration of mineral suspension was noted offshore in the Norwegian Sea and around Spitsbergen and the smallest in the central Atlantic Ocean.
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Abstract

The state of development, the existing and emerging forms of development, the intensity and legibility of settlement systems, all this is essential for the living conditions of urban residents, their surroundings and peripheral systems. The purpose of the article is to assess the accessibility to market and public services by estimating the distance to these services from housing facilities in Poland. The use of the residential dispersion ratio (RDR) and an analysis of the spatial distribution of municipalities with the highest values of the coefficient allows to identify areas where accessibility to public and market services is weak.
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Abstract

This paper presents the research studies carried out on the application of lattice Boltzmann method (LBM) to computational aeroacoustics (CAA). The Navier-Stokes equation-based solver faces the difficulty of computational efficiency when it has to satisfy the high-order of accuracy and spectral resolution. LBM shows its capabilities in direct and indirect noise computations with superior space-time resolution. The combination of LBM with turbulence models also work very well for practical engineering machinery noise. The hybrid LBM decouples the discretization of physical space from the discretization of moment space, resulting in flexible mesh and adjustable time-marching. Moreover, new solving strategies and acoustic models are developed to further promote the application of LBM to CAA.
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Abstract

In this work, the 316L austenitic steel based milled and sintered composites with 0.33 wt% and 1 wt% SiC ultra-fine particles addition have been prepared. The high efficient attrition milling provided an efficient size reduction of the 316L steel grains and homogeneous distribution of the SiC nanoparticles before sintering process. Spark plasma sintering (SPS) was used for compaction of milled powder mixtures. The effect of SiC addition on the milling efficiency and the structure of the composites have been studied. It was found that the amount of ceramic addition did not influence the efficiency of milling process, powder mixtures with flake like grains have been obtained. On the other hand, the intensive milling assured an optimal coverage of 316L stainless steel grains with submicron sized ceramic particles in both cases. The sintered composites showed high densities with the presence of small amount of closed porosities. Structural, mechanical and tribological examinations of 316L/SiC composites have been performed and presented.
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