Jelena Trajković

Polycarboxylic acids as non-formaldehyde anti-swelling agents for wood

Abstract Wood specimens of fir (Abies alba Mill) and beech (Fagus sylvatica L.) were chemically modified using polycarboxylic acids (PCA), cured by convection heating or microwave treatment and analyzed by HPLC. A new non-formaldehyde cross-linking system was composed of citric acid (CA) and 1,2,3,4-butanetetracarboxylic acid (BTCA), which are representative polycarboxylic acids (PCAs). These reagents require phosphono-based catalysts, so a sodium hypophosphite (SHP) catalyst was used in this study. The effects of PCA treatment were compared with a previously introduced 1,3-dimethylol 4,5-dihydroxy ethylene urea (DMDHEU) treatment. The dimensional stability of the modified wood was determined in terms of the anti-swelling efficiency (ASE) using the water soak/oven dry method. The results revealed an improvement in ASE for wood modified with PCA compared to modification with DMDHEU. Qualitative and quantitative determinations of bound acids were performed by HPLC. Further intensification of the wood modification process and an increase in the quality of wood-based materials were achieved using microwave treatment. Among other benefits, the formation of cross-links between the wood and the reagent components led to an improvement in the tensile strength retention, particularly in combination with the microwave treatment.

Scenes from the Past: CT-guided Endoscopic Recovery of a Foreign Object from the Cranial Cavity of an Ancient Egyptian Mummy

The aim of this study was to test the value of computed tomography (CT)-guided endoscopy in the scientific study of mummified remains and the recovery of unidentified objects from ancient mummified remains. CT-guided endoscopy was performed on an Egyptian mummy from the Late Period to help retrieve an unidentified object from its skull. The combined use of CT and endoscopy facilitated the recovery of the object, minimizing further damage to the remains and to the object itself. The successful recovery of the brittle object allowed detailed analysis of the item to be performed in an attempt to determine the nature of its presence in the cranial cavity. It was confirmed that the object was a monocotyledon stem fragment. Relying on the existing literature on mummification and excerebration methods in ancient Egypt, we concluded that the stick was probably used for transnasal removal of the brain. The results of this study demonstrate the great potential of CT-guided endoscopy for minimally invasive recovery of small unidentified items from mummies that could yield important information about mummification procedures and the materials used to preserve bodies.

The Echo (Jeka) Pavilion in Forest-Park Maksimir Zagreb - Restoration and Health Monitoring

The wooden pavilion Jeka (Echo) was built in 1843 according to the plans of the Austrian Empire garden architect Franz Schücht. Echo pavilion is the only remaining one of ten similar pavilions that were placed in the Forest-park Maksimir during the 19th century. Since 1964 the Echo pavilion has been protected by law and declared as cultural monument of garden architecture together with the whole park Maksimir, in which it is situated. Although the pavilion was restored several times (last time in 1986) it was in very bad condition. The reconstruction and preservation of the complete pavilions wooden construction were done after a careful analysis of its recent state in 2000. Restoration of the “Echo” Pavilion was started because its construction was in poor condition and because the whole pavilion was unsafe. There was a severe decay of the lower parts of the poles, particularly those faced to the North. New poles or only the new parts of the poles were made of glued spruce core surrounded by larch heartwood. Organic solvent Tebuconazole and WOODCAP products were used in wood preservation. The restoration of the Pavilion can be seen as an attempt to extend the life time of a severely damaged cultural monument, or at least in those parts of the monument where the amendments were possible. During reconstruction a monitoring system for wood moisture content at three different positions inside the roof construction was installed. Twice a year the pavilion is being carefully visually inspected and data from data logger downloaded and correctness of the equipment verified.This example of the “Echo” Pavilion is showing that moisture monitoring systems can considerably contribute to prevent cultural heritage from decay. The installed inexpensive and simple monitoring system of early warning proved to be feasible and saved costs in the conservation of wooden cultural heritage. In times of tight budgets and increasing rates of decay moisture monitoring systems will become increasingly important.