Alessio Ferluga

Thermal and acoustic performance expectations on timber buildings

In recent years, building technologies have been developed in order to improve comfort and energy saving. European institutions and single countries firmly invite individuals to choose high energy-saving strategies in order to decrease carbon emissions and energy consumption. Examples could be found in thermal insulators added to façades and improvement of glazing performance. At present, two technologies are the most used in construction realization: traditional (concrete, masonry or in general heavyweight structure) or wood (timber, crosslam or in general timber lightweight structure). Designers, scientists and builders have their own opinions on these two topics, but good insulation performance are achievable with both of them. Nevertheless, for lay people as well as for designers, wooden structures seem more comfortable, reliable and insulated. Therefore, an international survey was realized in order to investigate what individuals expect from these two different construction technologies in terms of insulation performance. Results indicate that timber buildings stereotypes are confirmed for acoustic and thermal insulation and show how scientific communication may help to deal with new or untraditional constructions.

Low frequency noise and disturbance assessment methods: A brief literature overview and a new proposal

Several studies have presented the effects of environmental noise on communities, focusing attention on sleep time events. The noise introduced into a dwelling is mostly evaluated using the A-weighted sound pressure level (LAeq) as the only parameter to determine the perceived disturbance. Nevertheless, if noise is produced by activities or sources characterised by a low frequency contribution, the measurement of LAeq underestimates the real disturbance, in particular during sleep time. The aim of this contribution is to analyse the low frequency disturbance phenomenon into technical and scientific literature and to investigate if any possible objective method is available in order to assess noise disturbance inside dwellings.

The effect of acetylation on hybrid poplar after artificial weathering

ABSTRACT The effect of acetylation on weathering resistance of a hybrid poplar (Pacific Albus®) was studied by colour change evaluation, mechanical tests, FT-IR spectroscopy and moisture absorption measurements. The acetylation process was performed without any pre-treatment and it was verified by means of weight percentage gain and FT-IR spectroscopy: the average weight percentage gain was 14.4 ± 0.6% and the band areas at 1370 and 1740 cm−1 increased about 50% compared to unmodified wood. It was also demonstrated that acetylation process increased mechanical performance and reduced wood moisture absorption. Unmodified and acetylated wood samples were artificially weathered with a Xenon-arc lamp up to 400 h. The mechanical properties of both acetylated and untreated wood showed the same trend, but acetylated samples exhibited higher stiffness, strength and elongation at break. The outcomes demonstrated that acetylated samples were more stable to degradation mechanisms induced by artificial weathering.