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11	Från utfällning till utställning : Konservering av järnföremål från Svarta jordens hamnområde, Birka RAÄ 119. L.23:II Heljeback, Mikael January 2016 (has links) The main purpose for this paper is to study iron artefacts excavated in the Black Earth harbour district of Birka. This locale, positioned on the island Björkö in Adelsö par. Sweden, is one of the mayor sites in regard to the Scandinavian Viking age. The how and why of the corrosive process will be touched upon. Specifically how archaeological iron interacts with the soil in which it is found, and what can be done to prevent unnecessary decay after excavation. This, in turn, leads to an observation of how methods have changed in regard to the conservation of archaeological iron, from the processes used in the early days of the field, to the more present day with the method utilized in this study. The conservation of said artefacts is for this study accomplished through the use of a conventional chemical method called EDTA. The usability of this method with waterlogged metallic artefacts is tested. The product of the conservation work revealed the objects to be mostly, iron rivets, bolts or nails. Not too surprising when the articles came from an area widely believed to be a harbour. This specific chemical solution proved not to be a sufficient conservation method for the waterlogged metal objects examined in this paper. This was due to the notably hard crust that covered the objects and the structural fragility of the artefacts. Specific analyses of some of the artefacts were undertaken due to the emergence of substantial amounts of depositions in the final steps of the process. Using XRD, XRF and IR-spectroscopy, the depositions were analysed and the result showed that the depositions most likely consists of a blend of non-water-soluble iron phosphates. archaeological science EDTA conservation iron Birka rivet corrosion waterlogged XRF XRD IR-spectroscopy phosphate laborativ arkeologi EDTA konservering järn Birka nit korrosion vattendränkt XRF XRD IR-spektroskopi fosfat
12	An investigation of seasonal disturbance intensity on wetland grass belts of Nysvley Nature Reserve Gelebe, Vhuhwavho 17 May 2019 (has links) MSc (Botany) / Department of Botany / The use of disturbance in the management of Savanna is a common rangeland practice in South Africa. A two-season trial was established in June 2016 and December 2016 to evaluate the effects of disturbance of different intensities on wetland belts in the Nylsvley Nature Reserve. The disturbances were in three different belts of different grass types at different intensities. The experimental treatments consisted of two different intensities, namely; high (H) and low (L). The Cyperus amabilis belt was regarded as site 1, the Sporobolus africanus as site 2, and the Themeda triandra as site 3. Seventeen kites were contracted in each belt, two times 1 m × 1 m at high and low intensity, followed by two times 2 m × 2 m one at high intensity. The results showed that disturbance affects the topsoil by removing the soil which is rich in nutrients producing pioneer species for the first few months and then original species were seen inhibiting again. / NRF Disturbance Low intensity High intensity Wetland belt Waterlogged Clay soil Cyperue amabilis Cynodon dactylon Setaria sphaceleta Themenda triandra Sporobolus africanus 577.6840968257 Wetlands -- South Africa -- Limpopo

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Från utfällning till utställning : Konservering av järnföremål från Svarta jordens hamnområde, Birka RAÄ 119. L.23:II

An investigation of seasonal disturbance intensity on wetland grass belts of Nysvley Nature Reserve