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121.
The anelastic nonhydrostatic model EULAG is a candidate for the future dynamical core of a numerical weather prediction model.
Achieving such an objective requires a number of experiments focused on testing correctness of the solutions and robustness
of the solver. In the spirit of this idea, a set of tests related to standard atmospheric problems was performed, of which
the two regarding development and evolution of a supercell were employed as benchmarks of moist dynamics of the model. Their
results are discussed in this paper. Development and evolution of a stormsystem with a set of characteristic features such
as stormsplitting along with the generation of horizontal vorticity and cold pool formation is investigated. In addition,
the influence of domain geometry, boundary conditions and subgrid-scale mixing is examined. 相似文献
122.
Rhodamine B and Rhodamine WT are fluorescent dyes commonly used as tracers in hydrological investigations. Since introducing
intensely red substances into rivers raises understandable doubts of ecological nature, the authors aimed at examining the
influence of these dyes on small water fauna using bioindication methods. Quantitative results, calculated with the use of
Bliss-Weber probit statistical method, were achieved by means of standardized ecotoxicological tests containing ready-to-hatch
resting forms of fairy shrimp (Thamnocephalus platyurus). Qualitative studies included observation of water flea crustacean (Daphnia magna) and horned planorbis snail (Planorbis corneus), both typically present in rivers and representative for temperate climate, as well as guppy fish (Poecilla reticulata), paramecium protozoan (Paramaecium caudatum) and the above-mentioned fairy shrimp. The investigation revealed that both dyes in concentrations used for hydrological
purposes are low enough to exert almost no toxic impact on water fauna considered. 相似文献
123.
For the last sixty years, two institutions have shaped the destiny of the town of O?wi?cim in southern Poland. One of these institutions is globally recognised, its history and development widely researched; the other is well known only amongst Polish industrialists, perhaps Polish economic geographers, and amongst the people of O?wi?cim. These two institutions are the Auschwitz State Museum and the chemical firm Dwory SA. Both institutions have their roots in the German Occupation of Poland 1939-1945. This paper presents the tale of these two institutions in order not only to highlight the need to embed memorial sites in their wider contexts, but also to indicate the impact of such sites as political-economic institutions, with the influence to shape social and economic landscapes. In laying out the geographies of the town and its two major institutions, we draw attention to the ways in which Holocaust memorialisation and post-socialist transformation are articulated with each other, not only here in O?wi?cim, and also with wider processes of social, economic, political and cultural change. 相似文献
124.
A sediment core from the Arctic Revvatnet (Hornsund area, SW Spitsbergen, Svalbard) provided data on environmental changes over the last 3100 years. Diatom analysis showing the domination of planktonic Cyclotella forms suggested good edaphic conditions until the middle of the nineteenth century, even during the Little Ice Age. A thermally stratified and relatively stable water column with good mixing allowed small, less heavily silicified Cyclotella sensu lato to develop during this time. The climate warming at the beginning of the twentieth century induced intensification of erosion processes in the catchment of the lake and caused an increase in the sedimentation rate. These processes have caused a lack of thermal stratification by disturbances in the water column and an increase of nutrients, consequently driving changes in the diatom species composition, which became dominated by benthic forms. In this period, almost all planktonic taxa disappeared or abruptly decreased in frequency. Higher temperatures accelerated the melting of nearby glaciers, which caused an increase in the activity of diatoms typical of running waters. Also a few Cladocera species appeared at the first time in the youngest samples. 相似文献
125.
126.
Microconchids are a group of tiny, encrusting tubeworms. They appeared in the Late Ordovician, some 450 Myr ago, flourished during the rest of Palaeozoic and Triassic, and became extinct in the Middle Jurassic. Their morphological resemblance to the sedentary polychaete genus Spirorbis, very common in marine environments, misled various authors for decades. This mistake originally gave the genus Spirorbis an enormous stratigraphical range, from Ordovician to Recent. Indeed, microconchids provide an excellent example of evolutionary convergence with respect to both their morphology and ecology. In the late 1970s these ‘spirorbids’ were interpreted as vermetid gastropods on the basis of the inner architecture and microstructure of their tubes. This idea, however, was challenged in the 1990s when detailed microstructural investigation showed them to be neither polychaetes nor gastropods, but closely related to an extinct Palaeozoic enigmatic group of organisms called tentaculitids. No thorough investigation of their origin, phylogeny and ecology has ever been conducted, but new data concerning their palaeobiology has come to the light during the last few years. 相似文献
127.
The spread of a passive contaminant in an open-channel reach is considered with use of a two-dimensional advection-diffusion
equation with the included off-diagonal dispersion coefficients. This paper presents the calculation of truncation errors,
namely numerical diffusion and numerical dispersion for various finite difference schemes. The accuracy of the considered
finite-difference approximations is analysed by deriving and studying the relevant modified partial differential equation. 相似文献
128.
129.
Marcinków(Lower Silesia, ?nie?nik Masiff,south-western Poland) has been a well-known mining centre since the mid-15 th century. Mineral extraction ended in 1949 with the ores of Pb, Ag, Cu and occasionally Au, U or graphite mined there. The mine is surrounded by metamorphic graphite and mica schist. It is not open to the public and no bats have been recorded living in. The aim of this study was the mycological analysis of the air, the rock surface and the water of the disused ore mine of Marcinków.Additionally, the chemical composition of rocks and water, and microclimate conditions of the adit were determined. Fungi were identified using a combination of phenotypic and molecular methods.Six taxa of fungi were cultured from the indoor air samples of the adit, whereas the outdoor air samples contained only five taxa. On the other hand, nine taxa were isolated from both the rocky walls and the water.The Aspergillus group was present only on the rocks and in the water, whereas Cladosporium herbarum,Dumontinia tuberosa, Epicoccum nigrum, Hirsutella sp., were found exclusively in the air. The mycobiota found in the ore mine were mostly similar to those recorded in other mines and natural caves. However,it should be noted that the internal microclimate and chemical compounds of the rocks. 相似文献
130.
The paper presents the results of investigations of physical and chemical properties of after reclamation dust that is generated in the foundry industry. Universally applied mechanical reclamation processes of spent moulding sands generate large amounts of after-reclamation dusts containing mainly rubbed spent binding agents and quartz dusts. An amount of after-reclamation dusts—in dependence of the reclamation system efficiency and the reclaim dedusting system—can reach 5–10 % in relation to the total reclaimed spent moulding sand. After-reclamation dusts originated from spent moulding sands with different kinds of resins mostly belong to dangerous wastes, since they contain chemo-setting binders with dangerous substances removed in the reclamation process. None of the companies producing mechanical reclamation systems offers presently the complex technology and equipment for utilisation of after reclamation dusts, which would meet technical and economic expectations of foundry plants. The paper presents the results of research carried out at the Faculty of Foundry Engineering AGH UST in Cracow which aims on the determination of possibilities of using the post-reclamation dust generated during mechanical reclamation of used moulding sands with organic resins as a source of energy. Different dusts generated in the mechanical reclamation process of used organic sands, delivered from foundries, were tested to determine their chemical composition, granular characterisation and physicochemical properties. As a result of the investigations, possible ways to utilise the dusts are presented. 相似文献