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Analiza wpływu litu na strukturę i właściwości odlewniczych stopów aluminium-miedź

100%

Zych H.

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tom R. 5, nr 3

15-21

PL

Scharakteryzowano lit oraz podano wpływ litu na stopy AlCuMg. W części eksperymentalnej zaprezentowane zostały wyniki badań stopu AlCu4TiMg, do którego wprowadzano lit do zawartości 4%. Badano wpływ zmiennych dodatków litu na mikrostrukturę i twardość stopu w stanie po odlaniu oraz po starzeniu. Wyniki prób i badań wykazały, iż lit bardzo intensywnie wpływa na zmiany zachodzące w mikrostrukturze stopu; wraz ze wzrostem zawartości litu w badanym stopie następuje bardzo duże rozdrobnienie mikrostruktury. Uzyskaną twardość w stanie po odlaniu można podwyższyć już poprzez samo starzenie, wykorzystując tzw. przechłodzenie odlewnicze.

EN

The first part of the article gave the characteristic of lithium and its influence for AlCuMg alloys. In the experimental part of the work the results of AlCu4TiMg alloy researches were presented. The AlCu4TiMg contained to 4% of lithium. The influence of variable additions of lithium for the microstructure and alloy hardness in the state after casting and ageing was researched. The tests and researches` results showed that lithium has big influence for the changes proceeding in the alloy microstructure. A very big size reduction of the microstructure goes together with the increase of the lithium contents in the tested alloy. The obtained hardness in the state after casting can be just increased by self-ageing, using the foundry over-cooling.

2

Biological markers and stable carbon isotope studies of bitumen impregnating Quaternary sediments at Starunia palaeontological site and vicinity (Carpathian region, Ukraine)

45%

Kotarba M. J. , Fabiańska M. , Więcław D. , Kowalski A. , Zych H.

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tom Vol. 79, No 3

463-480

EN

Biological markers and stable carbon isotopic compositions of bitumen impregnating the Pleistocene and Holocene sediments around the Starunia palaeontological site (Carpathian region, Ukraine) near discovered remnants of a mammoth and three woolly rhinoceroses, and one almost completely preserved rhinoceros carcass found in 1907 and 1929, were investigated. The research was carried out to assess genetic connections between the bitumen and oils from the nearby deep accumulations of the Boryslav-Pokuttya and Skyba units of the Carpathians. Another aim of these geochemical studies was to reveal the secondary geochemical processes (oxidation and biodegradation) influencing the bitumen, and to determine which environments have been favourable or unfavourable for the preservation of large Pleistocene vertebrates. Bitumen included within the near-surface rocks are not genetically connected with residual organic matter present in Quaternary sediments. Geochemical features, such as distributions of pentacyclic triterpanes and steranes, biomarker parameters and isotope composition indicate that all bitumens originate from oil-prone, Type II kerogen with insignificant admixture of terrestrial Type III kerogen in the middle stage of catagenesis. The oils occurring in deep accumulations in the Starunia area were the sole source of bitumen found in the near-surface sediments. Input of immature organic matter to bitumen from Pleistocene and Holocene sediments has not been found. The main factors differentiating the bitumen were: biodegradation, water washing and/or weathering. Additional influence of transport of bitumen by brine was found. The most favourable conditions for preservation of large, extinct mammals within the Pleistocene muds exist in the vicinity of Nos 22 and 23 boreholes, where bitumen is best preserved. The worst conditions were found in the vicinity of Nos 1, 4, 4' and 15 boreholes. Intensification of biodegradation and weathering effects were followed by intensive, chaotic changes of the remnants of large Pleistocene mammals.

3

Bitumen and salt contents within the Quaternary sediments at Starunia palaeontological site and vicinity (Carpathian region, Ukraine)

38%

Kotarba M. J. , Więcław D. , Toboła T. , Zych H. , Kowalski A. , Ptak S.

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tom Vol. 79, No 3

447-461

EN

Geochemical studies were conducted on bitumen and salts saturating the Pleistocene and Holocene sediments from an abandoned ozokerite mine in Starunia. This location is noted for the discovery of remnants of a mammoth and three woolly rhinoceroses in 1907, and a nearly completely preserved rhinoceros carcass in 1929. The bitumen (oil) and brines (chloride ions) were preserving agents for the large Pleistocene mammals. The main mass of organic carbon hosted in the Pleistocene muds is related to bitumen originating from oil migrating from deep accumulations within the Boryslav-Pokuttya Unit. The highest analysed bitumen content is 9.26 wt%. The chloride ion content, originating from highly concentrated brines ascending from the salt-bearing Miocene Vorotyshcha beds, vary from 0 to 4.66 wt% but this usually does not exceed 1 wt%. The natural pathways of underground fluids (oil, gas and water) migration within the Quaternary sediments were disturbed by intensive ozokerite mining operations run between the last three decades of the 19th century and 1960. Therefore, the present preservation and conservation conditions of large, extinct mammals' remains can be different from those prevailing during the Pleistocene, when the mammals were buried. Taking into consideration the contents of the remaining preservatives: chloride and bitumen, the most favourable zone for fossils conservation and preservation is located close to boreholes Nos 22, 23, 28 and 36N, where the thickness of Pleistocene muds exceeds 2 metres. Generally, the spatial distributions of bitumen and chloride ion contents within the Holocene sediments and salt-bearing Miocene Vorotyshcha beds are very similar to those in the Pleistocene sediments.