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BEGIN:VEVENT
UID:DSC-18283
DTSTART;TZID=Europe/Berlin:20220126T130000
SEQUENCE:1641466283
TRANSP:OPAQUE
DTEND;TZID=Europe/Berlin:20220126T140000
URL:https://dresden-science-calendar.org/calendar/de/detail/18283
LOCATION:Online\,   
SUMMARY:Naes: Kolloquium
CLASS:PUBLIC
DESCRIPTION:Speaker: Maram Naes (TU Berlin)\nInstitute of Speaker: \nTopics
 :\n\n Location:\n  Name: Online ()\n  Street:  \n  City:  \n  Phone: \n  F
 ax: \nDescription: Probing Chemical and Micromorphological Properties of G
 old in Historical Wall Paintings Using Lab and Synchrotron Investigation M
 ethods    Zoomraum: Meeting-ID: 873 3900 4773 Kenncode: 035976    Abstract
 :  Gilding materials and technology of Nabataean gilded wall paintings dat
 ing back to the 1st century AD were identified using various spectroscopic
  techniques. Micro-spectroscopic analytical investigations were performed 
 on wall painting and stucco fragments from various painted facades in Petr
 a. Non-invasive (NI) and non-destructive (ND) analytical methods were prio
 ritised in our investigation approach. Beside Optical Light Microscopy (OM
 ) and Environmental Scanning Electron Microscopy (ESEM)\, 2D and 3D Micro 
 X-Ray Fluorescence (µXRF) with laboratory and synchrotron sources were ut
 ilized. 2D elemental mapping of major components allowed the detection of 
 visually invisible (to bare eye) nanogold clusters. Moreover\, laboratory 
 and synchrotron Fourier Transform Infrared Spectroscopy (FTIR) were used t
 o investigate the molecular composition of the gilded samples. Chemical sp
 eciation of gold and iron in the historical samples were also studied usin
 g NI and ND X-Ray Absorption Spectroscopy\, both Near Edge (XANES) and Ext
 ended (EXAFS).     The results allowed defining gilding technology in Naba
 taean gilded wall paintings and stucco and categorising the paintings acco
 rdingly. Results showed that gilding materials and techniques did influenc
 e the current condition of gold layer at both macro and micro scales. A mi
 crographic glossary of gold’s layer micromorphology was developed and co
 rrelated with various deterioration mechanisms.    Remarkably\, gold and i
 ron speciation in the historical samples is found to be influenced by both
  composition and condition of the gilded painted surfaces. EXAFS analysis 
 at Au-L3 edge (11.919 eV) allowed the detection of various gold species in
 dicating possible reactions with iron oxide paint layer as well as inheren
 t and surrounding soluble chloride salts. Iron speciation showed the prese
 nce of various iron oxides and sulfates in relation to composition and con
 dition. Thermal influence (uncontrolled fire event in site’s history) on
  its oxidation state was evident in the pre-edge region at 7.1135 keV. The
 se findings are reported for the first time in historical gilded paintings
 \, certainly Nabataean. A selection of our results will be presented in th
 is webinar.    
DTSTAMP:20260422T200242Z
CREATED:20211123T130307Z
LAST-MODIFIED:20220106T105123Z
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