12 research outputs found

    Experimental and Numerical Study on Performance of Concrete Slabs Subjected to Severe Fire

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    Gang-Like Groups in Slovenia

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    XAS studies of the effectiveness of iron chelating treatments of Mary Rose timbers

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    The oxidation of sulfur in marine archaeological timbers under museum storage conditions is a recently identified problem, particularly for major artefacts such as historic ships excavated from the seabed. Recent work on the Vasa has stressed the role of iron in catalysing the oxidative degradation of the wood cellulose and the polyethylene glycols used to restore mechanical integrity to the timbers. In developing new treatment protocols for the long term preservation of Henry VIII of England's flagship, the Mary Rose, we are investigating the potential of chelating agents to neutralise and remove the iron products from the ships timbers. We have explored the use of aqueous solutions of chelating agents of calcium phytate, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) and ammonium citrate to extract the iron compounds. All of these solutions exhibit some level of iron removal; however the key is to find the most effective concentration at pH of around 7 of the reagent solution, to minimise the treatment time and find the most cost-effective treatment for the whole of the Mary Rose hull. Fe K-edge XAFS data from samples of Mary Rose timbers, before and after treatment by the chelating agents mentioned has been collected. The data collected provide valuable insights into the effectiveness of the treatment solutions. © 2009 IOP Publishing Ltd

    Novel fluorescent security marker. Part I: morphological and optical properties of 2-amino-6-ethoxy-4-[4-(4- morpholinyl)phenyl]-3,5-pyridinedicarbonitrile nanoparticles

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    Newly synthesized fluorescent nanoparti- cles of 2-amino-6-ethoxy-4-[4-(4-morpholinyl)phenyl]-3, 5-pyridinedicarbonitrile have been developed and characterized for possible applications as security marker in paper documents. Nanoparticles have been prepared by reprecipitation in water under sonication. The size and the shape of these nanoparticles, charac- terized by light scattering and atomic force micros- copy, have been found to be highly dependent on sonication power. Typical sizes range from tens to hundreds of nanometers. Furthermore, a remarkable increase in the fluorescence yield has been observed as nanoparticles sizes decrease. Finally, all of the above features, together with the striking stability of optical and mechanical properties over the course of months, allow for straightforward applications that rely on strong and stable fluorescence such as marking impor- tant or valuable documents
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