{"status":"OK","msg":"Details loaded!","presentation":{"id":72,"title":"EVALUATION OF A HELICAL VORTEX CLEANING PROCESS IN THE \"MENINA E MO\u00c7A\" MARBLE SCULPTURE USING PORTABLE EDXRF","abstract":"The white marble sculpture of Leopoldo e Silva (1879-1948), called \"Menina e Mo\u00e7a\" (23 x 147 x 40 cm), is kept in exposition in one of the hallway of the museum Pinacoteca de S\u00e3o Paulo, in which the public has direct access to it and it is even possible to touch the sculpture. As a result, the sculpture has dirt stains with brown shades over the white marble. A helical vortex cleaning system employing an air flux with calcite was performed as a blasting cleaning process. The calcite has a medium abrasiveness and its composition is similar to the marble sculpture. After the cleaning process a hydrophobic product based on silicon nanoparticles was applied (Silano\u00ae). This study consists in the surface qualitative characterization of the sculpture, which objective was to verify if the helical vortex cleaning process as well as if the hydrophobic sealant modify the surface chemical composition of the sculpture. A laboratory-made portable energy dispersive X-ray fluorescence (EDXRF) equipment, developed in the Applied Nuclear Physics Laboratory of the Universidade Estadual de Londrina, was taken to the Pinacoteca museum for the study. Fourteen measurements in different points were performed before helical vortex application, 7 measurements after the helical vortex cleaning and 3 measurements after the hydrophobic sealant application. Due to the limited available time for measurements, it was not possible to perform the same number of points before the cleaning. The operation conditions of the portable EDXRF equipment were: 35 kV, 5 \u00b5A and 200s excitatin\/ measurement time. In all the spectra the chemical elements P, S, Ca, Fe, Sr appeared. The highest intensity peaks were from Ca and Sr which are the major components of the marble. In some point Zn was detected before the cleaning process. It was noted that the Fe and Zn intensity peaks decreased after the helical vortex cleaning attesting that the surface was cleaned because Fe is the major component of dust. The spectra of the measurements after the sealant application were identical to the ones made just with the helical vortex cleaning. However, the detection limit of the portable EDXRF equipment is in tens of ppm for light elements, therefore the Si nanoparticles were enabled to be identified. In conclusion, the helical vortex cleaning process and the hydrophobic application are efficient for sculpture conservation and do not alter significantly the surface composition of the marble.","keywords":"X-Ray Fluorescence; archaeometry, marble sculpture.","status":"active","sarx_st":"accepted","user_id":95,"created_at":"2016-06-24 09:01:25","updated_at":"2016-08-20 12:18:44","filename":"Abstract (SARX2016)_FabioMelquiades3_2.doc","mode":"oral","sarx_code":"08_O-XRF","poster_group":null,"file":"9dd3c7565c6ff25061cbefeda38fbaa3.doc","author":"F\u00e1bio Luiz Melquaides","affiliation":"p\u00f3s doutor \/<\/b> UEL \/<\/b> Brazil","user":{"id":95,"name":"F\u00e1bio Luiz Melquaides","degree":"p\u00f3s doutor","email":"melquiades.fabio@gmail.com","username":"melquiades.fabio@gmail.com","confirmed":0,"confirmation_code":"YiwDoTY5eScOfJosdbLhAM82urjU8j","created_at":"2016-04-08 00:06:43","updated_at":"2016-08-11 08:28:53","sarx":1,"affiliation":"UEL","address":"PR 445, KM 380","zipcode":"86057-970 ","state":"Paran\u00e1","phone":"43 33714266","fax":null,"city":"londrina","country":"Brazil","status":"active","is_admin":0,"category":"professor","school":1,"icdd":0}}}