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Number of results: 156
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Abstract

The distribution of planktonic Ostracoda (Halocyprididae) was studied based on vertically-stratified zooplankton samples collected by hauling 200 p.m - mesh net by day and by night during two austral seasons: summer 1985/1986 and winter 1989, from the 1200 m deep Croker Passage off the Antarctic Peninsula. Seven species of Ostracoda were recorded: Alacia belgicae, Alacia hettacra, Melaconchoecia isocheira, Metaconchoecia skogsbergi, Boroecia antipoda, Disconchoecia aff. elegans and Proceroecia brachyaskos. The first three species, endemic to Antarctic waters, were predominant (about 90%). Generally Ostracoda were most numerous in 600-200 m layer in summer and in 1000-400 m layer in winter. In the investigated area there was a clear contrast between the abundance of Ostracoda during austral summer and scarcity during austral winter.
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Abstract

In 1920 qualitative and quantitative benthos samples collected in Barents Sea sublittoral in the years 1951-1983 154 species, 77 genera and 30 families of Amphipoda Gammaridea were identified. Species diversity was highest among the Lysianassidae, Oedicerotidae, Ampcliscidae, Calliopiidae and Pleustidae. Ampelisca eschrichti clearly dominated the material. This same species, plus Haploops setosa and Anonyx nugax were both the most frequently occurring and most numerous species. The distribution of amphipods in the Barents Sea sublittoral varies both in diversity and numbers by region, depth, sediments and water temperature. Zoogeographical changes are discussed in the present paper. Altogether 331 species of amphipods have been hitherto collected in the Barents Sea, of which 317 species, 126 genera and 39 families belong to the suborder Gammaridea.
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Abstract

In the material of nearly 2000 individuals of Asteroidea collected in Admiralty Bay, the largest bay of the South Shetlands, 36 species were determined, enriching the list of hitherto known asteroid species of this basin by 17 taxa. One of them, Peribolaster macleani, is recorded for the first time in Western Antarctic. The most frequent and abundant asteroids of Admiralty Bay were Odonlaster validus, Psilaster charcoti, Bathybiaster loripes obesus and Diplasterias brucei. The bathymetric and geographic distribution of all species are discussed.
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Abstract

The avifaunistic observations carried out in the tundra valley of the Sob River's upper course (west slopes of the Polar Ural) in July 1995 revealed the occurrence of 39 breeding and 8 non-breeding bird species. The most numerous were Anthus pratensis, Calcarius lapponicus, Phylloscopus trochilus and Anthus cervinus. The great variety of wetland and aquatic habitats had a decisive influence on species-richness and abundance of birds (jointly 30 breeding and 4 non-breeding species). Areas of low humidity were inhabited by 14 whereas anthropogenic habitats by 4 species. Most of them (except for eurytopic A. pratensis and C. lapponicus) occupied one-two habitats irrespective of their numbers. The density of Buteo lagopus was estimated at 1.67-2.00 p/10 km2. Three species of distribution ranges laying to the south from the study area, namely Bucephala clangula, Dendrocopos major, Circus macrourus, were noted in the valley. The results obtained have been compared with available data on the avifauna of the region concerned.
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Abstract

226 papers by Polish authors and co-authors have been collected. They deal with Antarctic or sub-Antarctic fishes and also their parasites. The majority (35.7%) of the publications discuss fish biology including growth, age, maturity, feeding and occurrence of particular species in the area. Fewer papers are devoted to parasitology (26.0%). Papers dealing with fish biomass and exploitation make up 18.5%. Papers dealing with morphology and systematics make up 6.6%. The remaining papers are devoted to technology, physiology, palaeontology and others.
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Abstract

Starostinella nordica gen. et sp. n. is described from the uppermost Permian (Kapp Starostin Formation) of the Kapp Starostin (Isfjorden) in West Spitsbergen. The new genus is attributed to Trachypsammiidae Gerth - a family incertae sedis among Cnidaria. Members of the Trachypsammiidae have been previously associated with different higher rank taxa within the Cnidaria, or their skeletons were interpreted as a result of symbiosis of a cladochonoidal organism (Tabulata) with an indeterminate hydroid or stromatoporoid. S. nordica gen. et sp. n. seems to support the latter assumption. Hydrocoralla of S. nordica have a simpler structure than those of other Trachypsammiidae and are branching like those of Cladochonus. Their thick-walled, horn-shaped hydrocorallites are surrounded with a very thick cortical zone of sclerenchyme organized into trabecular microstructure. The proper corallite wall is fibro-radial in structure, sharply distinct from the outer cortical zone.
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Abstract

Properties of a snow cover in the vicinity of Arctowski Station, King George Island (West Antarctica) were studied in 1991. Variations of snow quality and physical transformations were analysed against changes of atmospheric parameters, basing on water equivalent index and repeatable examination of snow pits. Essential dependence of snow cover distribution and snow structure from local climatic features and terrain morphology was found. Thawing occurs in the whole mass of snow, with its contribution of both liquid and gas water phases.
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Abstract

Mid-winter rapid rise of temperature in the vicinity of Arctowski Station, King George Island (West Antarctica) was studied in 1991. Depending on circumantarctic migration of cyclones, sudden drop in air pressure and foehn-like phenomenon intensified by local topography occurred. Two such events are described on May 13 and June 28, against meteorological conditions during autumn and winter. Extreme intensification of morphogenetic processes caused degradation of a snow cover, immense meltwater discharge, radical transformation of slopes, effective aeolian activity and dynamic modifications in a sea-shore zone.
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Abstract

Peat soils (FAO — Gelic Histosols) in the southern Bellsund coast area occur on slopes and terraces. They are formed in places favourable for plant growth, i.e. adequately moistened and fertilized largely with bird excrements. These formations belong to moss peats which are generally decomposed weakly and moderately to about 0.5 m depth. Their content of organic matter is equal to about 30-90%, but it is higher in terrace peats. The latter are more acidified than slope peats. The reaction both of slope and terrace peat soils is as a rule, slightly acid or neutral, and CaC03 content does not exceed 10%. As regards the content of macroelements, that of Al is the highest followed by Ca, Fe, Mg and P. Little K and Ti, and only traces of Na are found. Microelements occur in the following sequence: Mn, Zn, Cu, Cr, Ni, Pb, Co, Cd. Particularly Mn, Zn as well as Cu and Cd were found in a higher concentration. Slope peat soils are richer in macro- and microelements than terrace ones, e.g. 4 times in the case of Mg. Peat soils poor in ash parts (up to 25% ash), contain the fewest elements. Some regularities concern also a vertical distribution of the particular profiles but only with regard to terrace peat soils.
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Abstract

The paper presents a spatial distribution of changes of air temperature (T) in the Arctic. Estimates of their spatial relations in the study region were based on a correlation analysis. T in the Arctic is most strongly correlated spatially in winter and spring, and least in summer. The radius of extent of statistically significant correlation coefficients of changes of T at the stations Svalbard Lufthavn, Ostrov Kotelny and Resolute A is equal to 2000-2500 km in winter and 1500-2000 km in summer. An attempt was done to delimit the regions of consistent occurrence of the anomalies T with respect to the signs and magnitudes, as well as of the regions with the most coherent T. The Wroclaw dendrite method was used to solve this problem. Relations of the mean areał T of the climatic regions and of the Arctic as a whole, with the northern hemisphere of temperature and selected climatic factors are presented.
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Abstract

Henryk Arctowski Station, the research station of the Polish Academy of Science in Admiralty Bay, King George Island, West Antarctica, is one of the most heavily visited bases in Antarctica. Between the seasons 1991/92 and 1996/97, 12884 tourists were recorded. A specially designed tourist trail was marked to divert visitors toward alternative attractions, not only the station buildings. Tourist management goals include: environmental protection, minimising waste and pollution, respecting the rules relating to protected areas, and prohibition of collections and souveniring.
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Abstract

Four Geodynamical Expeditions of the Polish Academy of Sciences carried through wide research seismic program in West Antarctica in 1979-1991. Three of these expeditions operated in the Bransfield Strait. The experiment of deep refraction and wide-angle reflection in West Antarctica focused on deep structure of the lithosphere, mainly of the Earth's crust. The network of deep seismic soundings (DSS) profiles covered all the Bransfield Strait. Five land stations on the South Shetland Islands, three stations on the Antarctic Peninsula and nine ocean bottom seismographs (OBS) recorded seismic waves, generated by explosions in a sea. The Bransfield Rift and the Bransfield Platform form a marginal basin against a volcanic arc of the South Shetland Islands. The paper presents new results of 2-D seismic modeling for network of five selected profiles. Four of them, ranging in lenght from 150 to 190 km, crossed main structures of the Bransfield Strait and the fifth, which connected the other ones and was 310 km long, ran along the Bransfield Rift. Two or three seismic models were presented for each profile. Finally, mutually corrected and controlled 2-D models of described profiles were constructed. They all presented spatial complex structure of the Earth's crust in a young rift of the Bransfield Strait, including extent of its main element i.e. anomalous high velocity body (HVB) (Vp > 7.4 km/s), detected in 10-30 km depth range except profile DSS-4 (southwest part of the Bransfield Strait). This inhomogeneity is interpreted as intrusion of the upper mantle (?asthenosphere) during stretching of the continental crust. The Moho discontinuity was found at depth 30-35 km, with velocities equal to about 8.1 km/s.
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Abstract

Silicon – molybdenum cast iron commonly called SiMo due to its unique properties has becoming more and more interesting engineering material. The history and development of this alloy is relatively long but, due to the significant difficulties during the manufacturing process resulting in the lower final quality than expected, it has not been applied to often in practice. The biggest challenge is its brittleness as a result of the carbides precipitations. During last few years, thanks to the many important researches made and the general foundry technology development, the interest in SiMo iron has been rapidly growing, especially for the castings for heavy duty applications like corrosion, high temperature and wear abrasion resistant parts. In the article the heat treatment attempts to improve the microstructure of SiMo castings has been presented. The goal was to destroy or at least to refine and uniformly distribute the carbides precipitations to improve mechanical properties of the exhaust manifold castings for the cars. The experiments were carried out for the alloy contains approx. 4% Si, 1% Mo and 3.2%C. The range of the research included: hardness measuring, standard mechanical properties and microstructure for as-cast state and after that the subsequent heat treatment process with another properties check. The result of the heat treatment was the elimination of pearlite from the metal matrix. Moreover, the changes of the carbide molybdenum – rich phase morphology were observed. The dispersion of the carbides precipitations in the carbides area was observed. The experiments proved the possibility to control the microstructure and the mechanical properties of the SiMo castings by means of heat treatment but only to some extent.
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Abstract

A measuring system was developed for the measurement of ejector forces in the die casting process. When selecting the sensor technology, particular care was taken to ensure that measurements can be taken with a high sampling rate so that the fast-running ejection process can be recorded. For this reason, the system uses piezoelectric force sensors which measure the forces directly at the individual ejector pins. In this way, depending on the number of sensors, it is possible to determine both the individual ejector forces and the total ejector force. The system is expandable and adaptable with regard to the number and position of the sensors and can also be applied to real HPDC components. Automatic triggering of the measurements is also possible. In addition to the measuring system, a device and a method for in-situ calibration of the sensors have also been developed. To test the measuring system, casting experiments were carried out with a real aluminium HPDC aluminium component. The experiments showed that it is possible to measure the ejector forces with sufficient sampling rate and also to observe the process steps of filling, intensification and die opening by means of ejector forces. Experimental setup serves as a basis for future investigations regarding the influencing parameters on the ejection process.
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Abstract

The research described in this contribution is focused on fractographic analysis of the fracture area of newly developed eutectic silumin type AlSi9NiCuMg0.5 (AA 4032), which was developed and patented by a team of staff of the Faculty of Mechanical Engineering. The paper presents determination of the cause of casting cracks in operating conditions. Fractographic analysis of the fracture area, identification of the structure of the casting, identification of structural components on the surface of the fracture surface and chemical analysis of the material in the area of refraction were performed within the experiment. Al-Si alloys with high specific strength, low density, and good castability are widely used in pressure-molded components for the automotive and aerospace industries. The results shown that the inter-media phases Fe-Al and Fe-Si in aluminium alloys lead to breakage across the entire casting section and a crack that crossed the entire cross section, which was confirmed by EDS analysis.
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