Water has a major influence on wood properties, especially dynamic moisture cycles, which affect the wood in outdoor applications. It is thus important to understand the penetration and distribution of water in wood. In this study, rainfall events were simulated to correspond to water immersion periods of 1 h. Specimens were imaged by magnetic resonance imaging (MRI) after 1 h of immersion. These measurements were used to determine the water distribution in the wood and to elucidate changes during the drying of specimens of five wood species: sweet chestnut heartwood (Castanea sativa), European larch heartwood (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris) and Norway spruce (Picea abies). Both gravimetric and MRI analysis showed that after 1 h of immersion, pine sapwood took up the highest amount of water, followed by spruce wood. Considerably lower moisture contents were determined in pine heartwood, chestnut and larch, which correlated with a lower signal intensity. The outer parts of the specimens exhibited similar patterns with all of the specimens. The most variable results were the moisture content time profiles in the middle part of the specimens. Comparison of the MRI measurements and gravimetrically determined moisture contents during drying validated the MRI measurements and confirmed the method to be suitable for giving comprehensive information about the water drying kinetic. Journal Cellulose is the highly ranked journal within the field Material Science, paper and wood. Besides respective article, there were the following similar articles published: KRŽIŠNIK, Davor, BRISCHKE, Christian, LESAR, Boštjan, THALER, Nejc, HUMAR, Miha. Performance of wood in the Franja partisan hospital : Elektronski vir. Wood material science & engineering, ISSN 1748-0280, 2019, vol. 14, no. 1, str. 24-32, ilustr. http://www.tandfonline.com/doi/full/10.1080/17480272.2018.1438512, doi: 10.1080/17480272.2018.1438512. [COBISS.SI-ID 2878601]
COBISS.SI-ID: 2966665
Wood is one of the most important construction materials and its use in building applications has further expanded in recent decades. In order to enable even more extensive and reliable use of wood in outdoor applications, factors affecting wood’s service life need to be understood. It is well known that fungal degradation of wood is predominantly affected by temperature (T) and moisture content (MC). In order to elucidate the influence of these two factors, long term monitoring of T, relative humidity (RH) and MC at four locations was carried out: a model house made of thermally modified wood in Mozirje (1), the WWII partisan hospital Franja (2), a hayrack in Pokljuka (3) and a house in the north of Slovenia in Vrba (4). The results clearly showed that fungal degradation of wood is influenced by MC and T. In addition, the influence of micro-climatic conditions on fungal decay was shown.
COBISS.SI-ID: 2881929
After the durability of wood against wood decay fungi, its water performance is the next most important factor that influences the performance of wood in outdoor, above-ground applications. It is therefore of major importance to optimize methods that are able to predict the moisture behaviour of wood in outdoor applications. In order to elucidate these questions, samples were prepared from European oak (Quercus robur/Q. petraea), sweet chestnut (Castanea sativa), European larch (Larix decidua), Scots pine heartwood and sapwood (Pinus sylvestris), Norway spruce (Picea abies) and beech (Fagus sylvatica). The moisture performance of the samples was altered by thermal modification, wax, oil and biocide treatment. Two types of specimens were prepared; smaller specimens (1.5 2.5 5.0 cm) were exposed to natural weathering for three periods (9, 18 and 27 months) and subsequently analyzed in the laboratory with various methods (contact angle, short- and long-term water uptake and water vapor uptake). In parallel, bigger specimens (2.5 5.0 50 cm) were exposed outdoors in a monolayer exposure and equipped with moisture monitoring sensors for 18 months. Water performance of wood could change as a result of weathering, being the most evident at thermally modified wood, where the decrease of the moisture performance was the most evident. The results of the study clearly showed that the water performance of the majority of the materials decreased with natural weathering. These results... Besides respective article, there were the following similar articles published:KRŽIŠNIK, Davor, LESAR, Boštjan, THALER, Nejc, GRBEC, Samo, HUMAR, Miha. Risk assessment of mould growth on spruce wood during transport in an intermodal container : Elektronski vir. Maderas. Ciencia y tecnología, ISSN 0718-221X, 2018, vol. 20, iss. 4, str. 621-626, ilustr. http://revistas.ubiobio.cl/index.php/MCT/article/view/3222/3153. [COBISS.SI-ID 2929289] ŽLAHTIČ ZUPANC, Mojca, HUMAR, Miha. Influence of artificial and natural weathering on the moisture dynamic of wood. Bioresources, ISSN 1930-2126, 2017, vol. 12, iss. 1, str. 117-142. http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_12_1_117_Zlahtic_Artificial_Natural_Weathering_Moisture. [COBISS.SI-ID 2648969] ŽLAHTIČ, Mojca, HUMAR, Miha. Influence of artificial and natural weathering on the hydrophobicity and surface properties of wood. Bioresources, ISSN 1930-2126, 2016, vol. 11, iss. 2, str. 4964-4989. http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_11_2_4964_Zlahtic_Artificial_Natural_Weathering_Properties_Wood, doi: 10.15376/biores.11.2. 4964 - 4989. [COBISS.SI-ID 2555017]
COBISS.SI-ID: 2963849
The importance of the aesthetic performance of wood is increasing and the colour is one of the most important parameters of aesthetics, hence the colour stability of twelve different wood-based materials was evaluated by several in-service and laboratory tests. The wood used for wooden façades and decking belongs to a group of severely exposed surfaces. Discolouration of wood in such applications is a long-known phenomenon, which is a result of different biotic and abiotic causes. The ongoing in-service trial started in October 2013, whilst a laboratory test mimicking seasonal exposure was performed in parallel. Samples were exposed to blue stain fungi (Aureobasidium pullulans and Dothichiza pithyophila) in a laboratory test according to the EN 152 procedure. Afterwards, the same samples were artificially weathered and re-exposed to the same blue stain fungi for the second time. The purpose of this experiment was to investigate the synergistic effect of weathering and staining. The broader aim of the study was to determine the correlation factors between artificial and natural weathering and to compare laboratory and field test data of fungal disfigurement of various bio-based materials. During the four years of exposure, the most prominent colour changes were determined on decking. Respective changes on the façade elements were significantly less prominent, being the lest evident on the south and east façade. The results showed that there are positive correlations between these parametra.
COBISS.SI-ID: 2933385
Comprehensive approaches to predict performance of wood products are requested by international standards, and the first attempts have been made in the frame of European research projects. However, there is still an imminent need for a methodology to implement the durability and moisture performance of wood in an engineering design method and performance classification system. The aim of this study was therefore to establish an approach to predict service life of wood above ground taking into account the combined effect of wetting ability and durability data. A comprehensive data set was obtained from laboratory durability tests and still ongoing field trials in Norway, Germany and Sweden. In addition, four different wetting ability tests were performed with the same material. Based on a dose%response concept, decay rates for specimens exposed above ground were predicted implementing various indicating factors. A model was developed and optimised taking into account the resistance of wood against soft, white and brown rot as well as relevant types of water uptake and release. Decay rates from above-ground field tests at different test sites in Norway were predicted with the model. In a second step, the model was validated using data from laboratory and field tests performed in Germany and Sweden. The model was found to be fairly reliable, and it has the advantage to get implemented into existing engineering design guidelines. The approach at hand might furthermore be used... KRŽIŠNIK, Davor, LESAR, Boštjan, THALER, Nejc, HUMAR, Miha. Performance of bark beetle damaged Norway spruce wood against water and fungal decay. Bioresources, ISSN 1930-2126, 2018, vol. 13, iss. 2, str. 3473-3486. https://bioresources.cnr.ncsu. edu/wp-content/uploads/2018/03/BioRes_13_2_3473_Krzisnik_LTH_Perform_Bark_Beetle_Damaged_Spruce_Water_Fungal_Decay_13551.pdf. DE ANGELIS, Marco, ROMAGNOLI, Manuela, VEK, Viljem, POLJANŠEK, Ida, OVEN, Primož, THALER, Nejc, LESAR, Boštjan, KRŽIŠNIK, Davor, HUMAR, Miha. Chemical composition and resistance of Italian stone pine (Pinus pinea L.) wood against fungal decay and wetting. Industrial crops and products, ISSN 0926-6690, 2018, vol. 117, str. 187-196 BRISCHKE, Christian, HESSE, Carola, MEYER-VELTRUP, Linda, HUMAR, Miha. Studies on the material resistance and moisture dynamics of Common juniper, English yew, Black cherry, and Rowan. Wood Material Science & Engineering, ISSN 1748-0272, 2018, vol. 13, iss. 4, str. 222-230.
COBISS.SI-ID: 2724489