Your search resulted in 10 documents.
Validation by micro-computed tomography of an assessment method to measure the residual strength of anobiids infested timber
2019 - IRG/WP 19-20650
In this article a quantitative correlation study of pine timber structural elements, which have been subject to attack by anobiids, is presented. The main objective of the study was to establish a valid empirical correlation between the lost material percentage (consumed by beetles) and original/residual apparent density. Since the beetles’ attack produces a diffuse damage with a set of tunnels in random directions and sizes, this makes quantification more difficult. Micro-computed tomography (μ-XCT) was used to enable better assessment of material degradation state by quantifying the loss of density as this parameter is highly correlated with mechanical properties of timbers and thus central for the assessment. The results showed an experimental high correlation (r2=0.60) between original apparent density and lost material percentage and an even higher correlation (r2=0.83) between residual apparent density and lost material percentage. The results confirm the applicability of μ-XCT to define the relevant parameters for anobiid damage being this knowledge of fundamental importance for future validation of relevant non-destructive and semi-destructive techniques. After the μ-XCT study, screw withdrawal and shear parallel to the grain tests have been made in pine degraded timber. Screw withdrawal force and shear strength values were related with density loss (r2=0.82 for screw withdrawal; r2=0.78 for shear strength parallel to grain). A novel assessment method for evaluating the impact of anobiid damage on timber degraded structural elements based in four major steps is proposed enabling a more quantitative assessment of the structural soundness of the remaining timber.
J L Parracha, M F Pereira, A Maurício, P Faria, L Nunes
Studies on the infestation behaviour of the powder-post beetle Lyctus brunneus (Steph.) and its physical control in the wood yards of the Caspian forests of Iran
1985 - IRG/WP 1271
Lyctus brunneus (Steph.) is a pest which has not been previously thoroughly studied in Iran. It severely attacks Iranian hardwoods, especially those used in wooden houses and that have not been treated. Research work was necessary to determine the natural resistance of the most important timber species in Iran against this insect.
Formulating aesthetic coatings to prevent carpenter bee infestation
2007 - IRG/WP 07-30438
Our study shows that carpenter bees are getting more and more aggressive in attacking construction wood in the USA and southern parts of Canada, causing more-than-cosmetic damages. We have responded to a number of customers’ requests to identify and eradicate the culprits but the new generations of the bees would attack the same structures again. Therefore, Sansin invested into a project to formulate a decorative coating with a preventive action against carpenter bee infestations. Preliminary tests and results are reported in this paper.
Some studies on natural resistance of different trees and prevention of infestation by termites through use of industrial effluents at Karor, Layyah, Pakistan
2008 - IRG/WP 08-10637
The experiments were conducted to determine natural resistance/susceptibility in woods of Jaman (Syzygium cumini), Kikar (Acacia nilotica Willd.), Shisham (Dalbergia sissoo Roxb.), Poplar (Populus deltoids), Semal (Bombax ceiba) and Sufaida (Euclyptus camaldulensis) against subterranean termites’ infestation at Karor, Layyah, Pakistan. Wood stakes of these trees (30x12x3cm) were buried in soil and percentage infestation was recorded after 40, 80, 120, 160 and 200 days. Wood stakes were put inn sun drying kiln made of glass from three sides. Woods of kikar and Jaman remained free from termites’ infestation until 80 days whereas a range of 6.26 to 18.14% infestation was recorded on other woods during this period. Application of industrial effluents (textile, tannery and fertilizer) showed significant reduction in infestation percentage and weight loss in woods of Shisham, Semal, poplar and Sufaida. Woods treated with textile waste had comparatively and significantly less infestation and weight loss as compared to control wood in all cases. The possibility of application of these wastes on woods of different trees has been discussed in reference to the site of studies.
S Ahmed, M Arshad Ejaz, M Asam Riaz, A Hussain
Prevelence of termite infestation and wood preferences in Pakistan
2009 - IRG/WP 09-10695
In order to know about prevalence of termite infestation in Pakistan, A study was carried out to know the intensity of infestation of different species of termites to different types of woods used in buildings as well as in the forests. Heterotermes indicola was the most notorious species of termite present in buildings, grounds throughout the year while Odontotermes obesus was most common in forests. Of the different kinds of woods used in buildings, Sagwan was reported to be highly resistant in buildings. As far as public perception of termites is concerned, only 2% of the people have the knowledge about termite and its proper treatment. In the second part of study, 10 heartwoods of local timbers used in Pakistan were evaluated for their ability to resist termite damage by Heterotermes indicola. Woods were evaluated for forced feeding and not forced feeding bioassays in the laboratory as well in the field for 4- weeks. Tested woods were evaluated for Mean visual ratings, Mean wood mass loss and Mean % mass loss. At the end of experiment, in the field for H. indicola, the wood specimens were arranged in the following descending order of preference Ficus religiosa(FR)< Albizzia lebbeck (AL) < Eucalyptus citriodora(EC) < Heterophragma adenophyllum (HA) < Terminalia arjuna (TA) < Melia azedarach ( MA) < Alstonia scholaris (AS) < Abies pindrow (AP) < Pinus wallichiana (PW) < Erythrina suberosa (ES). In laboratory experiments, both by choice and No choice feeding, the woods were arranged the following order of preference Heterophragma adenophyllum (HA)< Ficus religiosa(FR)< Terminalia arjuna (TA)< Albizzia lebbeck(AL) < Pinus wallichiana (PW) < Alstonia scholaris (AS)< Erythrina suberosa (ES)< Eucalyptus citriodora (EC) < Abies pindrow (AP) < Melia azedarach ( MA).
F Manzoor, S Asma Malik
Evaluation of fungal infestation and decay in a simulated use class 3 situation (block test) after some years of exposure
2012 - IRG/WP 12-20487
The so named “block test” was designed as part of the assessment methodology for testing the behaviour of natural and modified wood used under use class 3 (EN 335-2) conditions. The test was developed to expose the wood close to the ground to an environment with high humidity and high biological activity, but not in soil contact. The present study describes the evaluation of fungal infestation and decay of untreated samples in different blocks depending on their exposure time, positioning within the block and wood species. After 4 years outside exposure samples showed visible signs of decay. The highest rate of decay was visible in the middle layers of the block. After 7 and 8 years outside exposure, samples of all layers were infested with a similar intensity of different types of decay. The results have shown that in the bottom layer close to ground the major type of decay is white rot as well as white rot in combination with soft rot. In contrast, samples from the middle layers and top layer were infested mainly by brown and white rot but also soft rot was observed. The test setup is according the definition of use classes a method for use class 3 applications because the samples are out of ground contact. But the infestation of samples in all layers by soft rot indicated that under use class 3 test conditions but with elevated moisture conditions soft rot attack can occur and should make part of a proper test design.
A Gellerich, K Röhl, S Adamopoulos, H Militz
Recommendations for handling of mold infestation of wooden artifacts
2012 - IRG/WP 12-10790
The presentation gives an overview of the handling of wooden artifacts with mold infestation. The causes of mold deterioration are demonstrated by investigations in a church, a historic library and a monastery in Germany. Investigated infested wooden artifacts were altars, sculptures, picture frames and sarcophagi. Important investigation methods including indoor climate measurement, material and air sampling, microscopy, lab investigations and determination of the mold species are described. The most typical mold species are discussed. Whereas various species of Penicillium are typical fungi, found after water injuries (condensation, leakage, flood), these fungi were not often found in wooden artifacts. Instead, for example, Trichoderma sp. and Aureobasidium sp. were frequently detected on the materials and caused discoloration. Contemporary measures for disinfection and protection of both wooden artifacts and the health of the restorers are shown by examples. Problems are discussed and possibilities for the removal of molds and material preservation by chemicals are shown.
K Plaschkies, B Weiss, W Scheiding
Using X-ray micro-CT to evaluate density loss in anobiid infested wood
2019 - IRG/WP 19-10956
Considering the relevance of wood borers in construction, the present study had as main objective the evaluation of the impact of anobiid damage on timber elements by establishing an empirical correlation between lost material percentage (LM%, consumed by beetles) and apparent density (original – OTD and residual – RTD). Since the beetles’ attack produces a diffuse damage with a set of tunnels in random directions and sizes, this makes quantification more difficult. In this context, micro-computed tomography (µ-XCT) is essential to enable better assessment of material degradation state as a function of lost material percentage/loss of density. The results showed a high correlation (r2 = 0.85) between RTD and LM% and a medium correlation (r2 = 0.60) between OTD and LM%. The various steps required during the µ-XCT study from the scanning procedure to the final quantitative results are also presented in this study enabling its use as guidelines for future studies.
J L Parracha, M F Pereira, A Maurício, P Faria, L Nunes
Dynamics of fungi colonization on the surface of Scots pine wood during natural weathering in different European climate zones
2022 - IRG/WP 22-10984
Wood The presence of fungi leads to biomaterial decay and/or changes in aesthetical appeal. The start of fungi colonization as well as the following growth on wood are primarily influenced by four factors: ambient temperature, moisture history of the object, access to oxygen, and intrinsic properties of the exposed wood, considered here as a source of nutrients for microorganisms. A prevalence of fungal spores in a close vicinity, combined with favourable environmental conditions are indispensable for the initiation of the growth of microorganisms. All the above factors are highly dependent on the local circumstances and especially climate conditions. It is important to understand the effect of weather on the diversity and distribution of endemic fungal communities in advance, to identify plausible remedies as related to the present global climatic changes. It is foreseen that the composition of fungal cultures as well as their growth kinetics on various wood substrates may evolve in the near future. The goal of this study was to investigate the relationship between specific weather conditions, representing diverse climate zones, on the occupancies and colonization dynamics of fungi/mould species. The test was performed on untreated Scots pine (Pinus sylvestris L.) wood samples exposed to natural weathering for 12 weeks from July to September 2021, in two locations: 1) Izola (Slovenia, 45°32'12.98"N, 13°39'42.98"E), representing the mild Mediterranean climate of southern Europe, and 2) Skellefteå (Sweden, 64°45'2.41"N, 20°57'10.04"E) representing Scandinavian or northern Europe climate zone. The local weather conditions recorded during the exposure period were used for modelling the growth kinetics. Fungi colonizing wood surfaces were manually collected from twin samples at each location, every second week, by swabs and cultured on nutrient media. The identification of fungi was performed visually according to the mycological keys of the detected genus. The presence of fungi was first noticed after 2 weeks of exposure. The majority of species detected were Ascomycetes from the genus Cladosporium, Aureobasidium, and Aspergillus. The combination of climatic parameters influences the compositions and colonisation of microorganisms on Scots pine wood. However, the obtained results showed fluctuations in the colonisation of the spores of culturable fungi. This might be the influence of other factors including geographic location, sensitivity of each fungal species to environmental factors, animals, plants, human activities, and pollutants that need to be taken in account.
F Poohphajai, O Myronycheva, O Karlsson, L Rautkari, J Sandak, A Sandak
Changes in topochemistry and mechanical properties of Beech (Fagus orientalis L.) by natural fungus infestation
2022 - IRG/WP 22-10986
Beech is one of the major hardwood species in Europe. It is, however, highly susceptible to fungal attack both in the fresh state and during the storage. Understanding the alteration in chemical and mechanical properties of beech wood during the initial degradation state can lead to improved raw material utilization. Therefore, UV-microspectrophotometer (UMSP) and High-Performance Liquid Chromatography (HPLC) were employed to study the chemical changes in beech (Fagus Orientalis L.) samples infested naturally by white rot fungi. The mechanical properties of infested beech were also determined and compared with the sound wood. The UMSP showed an apparent degradation in the region of the S3 and the S2 layers. HPLC analysis illustrated that catechin was the main component both in sound and infested beech wood. Considerable reductions in the mechanical strengths, bending properties and compression strength, were also apparent due to infestation.
H Sivrikaya, M Rehbein, F Divos, S Adamopoulos, R Hosseinpourpia