Optimizacija metode za zatiranje lesnih škodljivcev z mikrovalovi na predmetih kulturne dediščine : doktorska disertacija
Optimization of eradication of wood pests with microwaves in objects of cultural heritage : doctoral dissertation

slovenian

doktorska dela

2016

cultural heritage    microwaves    wood preservation    insects    surface coatings   fungus 

Univerza v Ljubljani, Biotehniška fakulteta

All over the world there have been several methods developed for eradication of wood pests. Due to the inestimable value of the objects that are considered for conservation, the requirements for repressive protection are much more stringent for cultural objects than for industrial wood. The microwave method is fast and effective, but so far it has been insufficiently explored as a treatment for objects of cultural heritage. In this study, we determined the conditions for the destruction of Hylotrupes bajulus larvae and four of the most common wood fungi. We used a 750 W commercial microwave chamber as well as an 88 W horn antenna microwave device with a 2,45 GHz frequency that was developed for targeted radiation. For the successful suppression of Hylotrupes bajalus larvae the wood need to be heated to 54 °C for >10 seconds, for Coniophora puteana >71,2 °C (5 min), Gloeophyllum trabeum >68,8 °C (15 min), Poria vaillantii >67,8 °C (15 min) and for Serpula lacrymans >71,6 °C (5 min). We have examined what the impact of extermination temperatures and exposure times have on the changes and damages to original paint samples that were taken from cultural objects, as well as newly prepared coatings. We evaluated visual, mechanical, and chemical modifications of the coatings when exposed to microwaves at 60 °C or 80 °C (10 min). Temperatures reaching up to 60 °C did not cause any changes in the material. Older coatings are more resistant to higher temperatures than newly prepared surface coatings and they did not show any damage on temperatures ranging up to 80 °C (10 min). The results of these tests and methods show that, in practice, microwave radiation is suitable for treatment of the majority of wooden objects of cultural heritage, if the heating process is controlled and items are not exposed to unnecessary high temperatures or excessive exposure.

26.05.2017