Tetraethylene glycol thermooxidation and the influence of certain compounds relevant to conserved archaeological wood

The degradation of tetraethylene glycol (TEG) was studied at 70 °C under dry air and nitrogen. Degradation products were detected using gas chromatography-mass spectrometry (GC–MS). They were mono-, di- and tri-ethylene glycol, mono- and di-formates of mono-, di-, tri- and tetra-ethylene glycol and formic acid. The rate of TEG degradation was significantly decreased by approximately 10 mmol/l KI, FeCl₃, Cu(CH₃COO)₂, MnO₂ and CuSO₄, small amounts of fresh oak wood sawdust and gypsum-containing scrapings from the wood surface of the Vasa ship in Stockholm. Thus certain salts and natural components of archaeological wood are able to inhibit oxidative degradation of TEG. NaFe₃(SO₄)₂(OH)₆ (Natrojarosite), FeS₂ (pyrite), FeSO₄, Fe₂(SO₄)₃, NiCl₂, NiSO₄, Fe, Cu, Fe₂O₃, CuO, NaHSO₄ and natrojarosite-containing scrapings from the Vasa had no major effect on the rate of oxidation.     

Production technology and knowledge transfer of calcite-tempered grey ware bowls from 2nd- to 5th-century ce Noricum (Austria)

Aspects of 2nd- to 5th-century ce Roman production technology and knowledge transfer in southern Austria (known as Noricum) were examined. With no evidence for workshops identified in the study area, 44 grey ware bowls from two sites at Aguntum and Lavant were studied macroscopically, and combined with optical microscopy, X-ray powder diffraction, prompt gamma activation, neutron activation and scanning electron microscopy, in order to understand whether one (large) workshop supplied these bowls, or whether the bowls were produced by several (small) workshops nearby. Combined with information from the geological background, the results were used to tentatively indicate the production location. The results indicate that the grey ware bowls from Aguntum and Lavant were produced by local workshops nearby. The bowls were manufactured with similar clay sources, tempered with crushed calcite-marble rocks from the Tauern Window, their surface smoothed and burnished, and fired between 800 and 850°C in a reducing atmosphere of an open fire. This is taken to suggest that Roman potters, who were located at Aguntum and Lavant, shared strategies of raw materials selection, paste preparation, finishing and firing, and transferred technological knowledge through time.