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Selective adsorption of antisapstain actives from two aqueous suspensions, and movement of actives into wood
1996 - IRG/WP 96-30103
Green-off-saw rough sawn Pinus elliottii (slash pine) boards were dipped in aqueous suspensions of two antisapstain formulations, NeXgenâ and Busanâ Sap Stain Preventative (Busan 1009), at three product concentration levels. Concentrations of active ingredients (NeXgen: CTL (chloro-thalonil) and MTC (methylene bisthiocyanate); Busan 1009: TCMTB (2(thiocyanomethylthio)-benzothiazole) and MTC) were monitored with respect to the amount of material dipped. Selective adsorption (removal of actives from the suspension at greater than simple volumetric transfer rates) varied with formulation and active ingredient, and increased with decreasing product concentration. Movement of active ingredients into dipped boards was monitored for 30 days after dipping. Mobility order was MTC >> TCMTB > CTL. Surface depletion characteristics were obtained for each active ingredient.
M J Kennedy, T L Woods

Kinetic modelling of adsorption of quaternary ammonium compounds by Scots pine wood sawdust (Pinus sylvestris L.)
2005 - IRG/WP 05-30369
The adsorption of new quaternary ammonium compounds from aqueous solutions onto Scots pine wood (Pinus sylvestris L.) sawdust was studied. The pseudo first- and second- order kinetic models were used for the mathematical description of the sorption dynamic process of QACs onto wood. The highest correlation coefficients were obtained for the pseudo-second order kinetic model, those suggest that chemisorption is involved in the adsorption process.
J Zabielska-Matejuk

Wood preservatives ecotoxicology on Gammarus pulex (L.) - toward an environmental monitoring method and a getting rid of pollution process
2005 - IRG/WP 05-50224-9
Wood preservatives can have a strong impact on freshwater invertebrates when used close to aquatic ecosystems. It has been reported in Jura that different arthropod taxa, specially crustaceans, have disappeared along several kilometers downstream from factories using insecticides and fungicides as wood preservatives. The crustacean Gammarus pulex (L.) is a relevant bioindicator to characterize the impact of wood preservatives on freshwater community. It presents a high sensitivity to wood preservatives but a relative tolerance to organic and nutrimental pollution. This abundant and ubiquitous crustacean has a key role in numerous aquatic ecosystems particularly in the decomposition of cellulose and as a prey for several fish species susceptible to be eaten by humans. In this study, we aim on the one hand to determine the adsorption capacity of different substrates of propiconazole, a fungicide widely used in the wood treatment, and on the other, to evaluate the toxicity of wood preservatives for G. pulex in controlled conditions. We hypothesize that the fungicide toxicity may be influenced by different types of substrate used in the test containers, i.e., coarse organic matter and gravel. These results should allow us to go, firstly toward the elaboration of sensors in order to detect product emissions in the aquatic environment, and secondly toward a depuration process in order to decrease the impact on the aquatic communities. These experiments should also allow us to develop a new biological monitoring method for the assessment of the impact of wood preservation on the aquatic ecosystems.
O Adam, F Degiorgi, G Crini, P-M Badot

CCA Chemistry
1983 - IRG/WP 3268
A Pizzi

The course of fixation of Cu-Cr-As wood preservatives
1972 - IRG/WP 307
Copper-chrome-arsenic (CCA) preservatives in contact with wood result in an instant extensive increase of pH, because of ion-exchange and adsorption reactions with the wood. During precipitation of the active elements the pH continuously increases but reaches a maximum, when all chrome is consumed. Some of the early reaction products are unstable and slowly convert via dissolution into stable compounds. The conversion proceeds by proton liberating as well as proton consuming reactions. The pH therefore alternatively decreases and increases until the reactions cease after several months. The final equilibrium fixation products are: ion-exchange fixation of Cu to the wood CrAsO4, Cu(OH)CuAsO4 and Cr(OH)3. The chrome fixation is 2nd order with respect to hexavalent chrome in the liquid phase, four regions with distinct chrome fixation rate constants were found. A hypothesis is given for the mechanism of fixation.
S-E Dahlgren

A contribution to the adsorption/desorption behaviour of zinc-hexa-fluoro-silicate in different soils
1995 - IRG/WP 95-50056
The estimation of a possible endangering of the groundwater through wood preservatives and thereof deriving measures for the avoidance of secondary damages require among others exact knowledge concerning the behaviour of wood preservative compounds in the soil matrix. Adsorption and desorption behaviour were determined at four soils of different characteristics, which were brought in contact with aqueous solutions of zinc-hexa-fluoro-silicate. For the respective experiments four concentrations were prepared containing 10, 50, 100 and 250 ppm zinc ions. Water of p.a. quality served as reference. As to be expected the soils in question behaved different: the adsorption of inserted ions increased with increasing clay content of the soil. On the other hand significant differences exist also with respect to the adsorption behaviour of the zinc cation in relation to the hexa-fluoro-silicate anion. Within the concentration interval investigated, the same soil adsorbed approximately the same proportional zinc quantity. However, when increasing the hexa-fluoro-silicate-ion concentration a proportional decrease concerning the degree of adsorption was observed. The results show that it is not possible to conclude from partial results achieved with individual preservative compounds to the overall system "wood preservative"-soil and that further investigations are necessary for an inclusive description of the problem.
E Melcher, R-D Peek

CCA modifications and their effect on soft rot in hardwoods. Part 2
1983 - IRG/WP 3244
The work outlined in this document is a continuation of that presented in Document No: IRG/WP/3201. The findings described in the previous paper are summarised below: a double treatment of CCB followed by arsenic (CCB+A) is more effective than a double treatment of boron followed by CCA (B+CCA) or a single treatment of CCA, CCB or CCAB in controlling soft-rot due to Chaetomium globosum in birch. CCB+A is as effective as the other formulations in controlling Coniophora puteana and Coriolus versicolor in birch and scots pine. CCB fails to copper tolerant basidiomycetes such as Coniophora puteana (F.P.R.L. 11E). A further investigation into the relative activities of CCA and CCB+A was carried out in a soil-bed using loss in strength and loss in weight as the criteria of decay. At the same time some aspects of the chemical nature of the formulations were examined in an attempt to explain the different performances of the treatments in birch. Amongst these tests, gross chemical analysis of the treated woodblocks and observation of the progressive fixation of the preservatives were the most significant.
S M Gray, D J Dickinson

Preliminary modelling of methylisothiocyanate movement through Douglas fir transmission poles
1988 - IRG/WP 3466
Methylisothiocyanate is a volatile solid that is the active ingredient of several registered and experimental wood fumigants. Information on the sorption and diffusion of this chemical in Douglas-fir heartwood and sapwood was used to develop a two-dimensional model of fumigant movement within a single horizontal cross-section of a transmission pole. The model indicated that dry wood (14% MC) strongly sorbed MIT, which resulted in lower rates of MIT movement. Conversely, it was predicted that wetter wood (22 or 40% MC) held MIT less strongly and had a more rapid rate of chemical movement. In addition, predictions suggest that the presence of an oil-treated peripheral shell had a strong influence on loss of fumigant from the surface of the pole, but had little effect on concentration which developed in the heartwood zone. The results indicate that MIT movement can be effectively modeled. Further studies are underway to account for longitudinal movement of MIT in the model and to simulate extended time periods.
A R Zahora, P E Humphrey, J J Morrell

Environmental fate of copper-based wood preservatives in different soil substrates - Part 2: Study of the metal sorption and migration potential under simulated rainfall
1998 - IRG/WP 98-50101-21 b
In order to examine the potential environmental impact of spillages of the saltborne wood preservative CCA in treatment plants, four large scale experiments are set-up so as to follow the water transport and ion mobility in various field soils. A plastic container is filled with a sand, silt, clay and potting soil, made up at their respective bulk density and wetted to a given moisture content. Using a rain simulator on top, a homogeneous spillage of a ready-to-use CCA solution is applied, followed by a rainfall simulation after 3 days and a 3 weeks redistribution period. Soil augers that are taken prior to each new perturbance reveal the distribution and migration pattern of the heavy metals. Copper and arsenic are strongly adsorbed in the upper soil layers, depending on the soil characteristics. Chromium, however, is percolated easily through the soil column and is readily extractable from the soil using pure water.
G M F Van Eetvelde, R Hartmann, J M Mwangi, H S Öztürk, M Stevens

Adsorption of ACQ and CuMEA Wood Preservatives in Red pine
2005 - IRG/WP 05-30374
The rates of stabilization or fixation of ACQ subcomponents (CuO, DDAC and MEA) in red pine (Pinus resinosa) were compared for different solution concentrations (0.75%, 1.5%, 2.25% and 3% ACQ-D) and post treatment conditioning temperatures. Preservative solutions were impregnated into red pine sapwood by a full-cell treatment. Copper and MEA adsorptions from copper monoethanolamine solutions without DDAC were also evaluated for comparison. After the treatments, samples were conditioned without drying either at 22° C for seven weeks or at 50° C for one week. At different times after treatment, expressate from the specimen blocks was analyzed for copper, DDAC and MEA. Copper and MEA adsorption by the wood cell walls followed similar trends. The equilibrium copper adsorption ranged from 44% at high ACQ retentions to about 95% for the lowest retention while the values in the CuMEA system were slightly higher for the higher retentions, ranging from about 54% to 93%. This suggests that DDAC may compete with CuMEA for reaction sites at high ACQ concentrations. Adsorption of DDAC into the wood cell wall matrix was rapid; at all solution concentrations, more than 80% of DDAC was adsorbed by red pine sapwood within minutes after treatment.
C Tascioglu, P A Cooper, Y T Ung

Environmental fate of copper-based wood preservatives in different soil substrates - Part 1: Screening of the metal adsorption potential
1998 - IRG/WP 98-50101-21 a
In treatment plants, spillage of wood preservatives onto soil may be of environmental concern. This potential soil contamination served as an objective for a screening study. Three different mineral soils, a mineral substrate and two horticultural substrates are examined for their sorptive potential of copper through mixing with wood preservative solutions. Depending on the soil/substrate characteristics and the chemical nature of the preservatives used, copper is adsorbed to a higher extent with increasing concentration of the test solution. Soils with low organic matter and clay content show an upper limit of adsorption, irrespective of the product tested. The other soil types clearly exhibit a levelling-out effect from 2 to 4 hours on, often correlating with the initial metal concentration of the product though dependent on the chemical nature and buffering capacity of the active ingredients.
G M F Van Eetvelde, J M Mwangi, F Tack, R Hartmann, M Stevens

Diffusion and interaction of components of water-borne preservatives in the wood cell wall
1988 - IRG/WP 3474
This study investigates the rates of diffusion and ultimate distributions of copper and arsenate components of wood preservatives in wood cell walls following vacuum treatment. Adsorption studies of copper on red pine (Pinus resinosa) and trembling aspen (Populus tremuloides) wood confirm the importance of cation exchange reactions on the ultimate distribution of copper in the wood substance and its strong dependence on pH of the treating solution. Formulations containing both copper and zinc preferentially adsorb or exchange copper relative to zinc. Under high pH conditions, the arsenate anion is significantly adsorbed into the cell wall. The combined adsorption and fixation of low pH CCA solutions is much slower than adsorption of high pH ACA and CZA formulations, but the reaction with wood is more complete. Diffusion coefficients were estimated for the movement of copper and arsenate components of ACA in cell wall material of both aspen and pine sapwood using a simple membrane model for non-steady state diffusion. The longer diffusion paths inherent in the diffuse porous hardwood (aspen) resulted in much slower equalization of the solute in the cell wall matrix than in red pine. However, in both species, equalization was achieved in a relative short time compared to accepted fixation times for conventional waterborne wood preservatives.
P A Cooper

Biosorption of metals for wood waste effluent clean up
1997 - IRG/WP 97-50090
The common filamentous fungi can sorb metal ions from aqueous solutions. The biosorption of metal ions like copper Cu2+, chromium Cr6+ and arsenic As5+ by dead fungal mycelia was investigated. Two industrial fermentation byproducts are tested: Mucor miehei and Aspergillus oryzae. The adsorption of metal ions depends on parameters such as chemical treatment of fungi before biosorption (acid or basic treatment), pH, adsorption time, metal ions and biomass concentrations. 88% of Cu2+ is recovered in one hour by Aspergillus oryzae and Mucor miehei (untreated and basic biomass). Cr6+ is adsorbed in 24 hours by these untreated biomass with a yield comprising between 40% and 65%. Similar results are observed for As5+ adsorption with Mucor miehei in regulated pH conditions. The most efficient systems Aspergillus oryzae (basic treatment) and Mucor miehei (untreated) were investigated in adsorption experiments on CCA-preservative solution (3% m/m). The adsorption yields for copper and chromium are respectively 90% and 80% in 24 hours. Removal of metals from CCA wastewater could be realized by these developped systems on site instead of conventional expensive processes.
S Legay, G Labat

Copper based water-borne preservatives: Copper adsorption in relation to performance against soft rot
1987 - IRG/WP 3452
As part of a fundamental study concerned with the performance of copper based water-borne preservatives the adsorption of copper from aqueous solutions by 4 hardwood and 1 softwood species has been studied. Experiments were conducted to determine the influence of solution pH, solution concentration and solution temperature. The results obtained were consistent with an acid form ion-exchange mechanism for copper adsorption. These properties of water-borne preservative solutions containing copper are discussed in relation to hardwood performance against soft rot decay.
P M S Rennie, S M Gray, D J Dickinson

Methods for the assessment of wood preservative movement in soil
1995 - IRG/WP 95-50040-08
This paper presents preliminary results from a series of experiments constructed to provide laboratory data for the evaluation of the leaching of wood preservatives into and through soil. The experiments included: i) measurement of the adsorption of preservatives by soil; ii) determination of the concentration gradient of preservatives in soil following percolation of preservative solution through soil; iii) determination of the changes in concentration gradient by subsequent leaching of contaminated soil with water. From an assessment of these laboratory procedures, based upon their practicalness and the results obtained, it was concluded that this range of tests could provide the necessary data to allow a rational appraisal of the potential of a wood preservative to contaminate soil. However, the experimental methodology needs to be examined further using a greater range of soil types, wood preservatives and water sources in order to establish the general acceptability of the approach and to allow standard procedures to be developed.
G E Holland, R J Orsler

Kiln drying of LSOP treated timber: rate of solvent evaporation, overpaintability and recovery of the solvent
1992 - IRG/WP 92-3711
The rate of solvent evaporation from LOSP treated timber dried in a kiln at 35°C has been investigated. Around 50% solvent removal has been found to be consistent with good overpaintability using a water based acrylic primer. It has been demonstrated that an activated carbon solvent recovery system is capable of removing all the solvent vapour from the outlet of a commercial joinery drying kiIn, that the solvent is subsequently recoverable using steam and that the recovered solvent is suitable for re-use.
P Warburton, L B Sheard

Effects of soil physical and chemical characteristics on adsorption of leached CCA and ACQ preservative components
2003 - IRG/WP 03-50200
The objective of this study was to examine the effect of soil characteristics on adsorption of wood preservative components from CCA and ACQ preservative systems. Adsorption of leached CCA and ACQ preservative components in soils with different characteristics were studied. Three soils (clay, sandy and organic) were investigated using different concentrations of leach water of CCA and ACQ wood preservatives made in the lab by extended leaching of treated sawdust. Samples of soil and leach water were equilibrated with shaking for 2 to 48 h at 22oC. Attempts were made to model adsorption results using the Langmuir adsorption isotherm. Supernatants of seven additional soils were sampled for one leachate concentration and after 48 h mixing. All soils were analyzed for content of clay, silt and sand (soil texture), organic matter, pH, CEC, concentration of Al, Mn, and Fe oxides. Multiple regression analysis was used to relate soil variables to the adsorption of CCA preservative components after 48 h of shaking for all ten soils, but there were no clear correlation. Arsenic adsorption in the clay soil was variable but appeared to be still increasing in the clay and organic soils after 48 hours exposure. The sandy soil stabilized at a relatively low amounts of all components. Adsorption of As, Cu and Cr showed high or moderately high correlation with concentration of equilibrating solution. An adsorption constant was not reached with this experiment because concentration of As, Cu and Cr in leachates were low. Consequently, adsorption of preservatives components did not follow the Langmuir isotherms. Adsorption characteristics at these low concentrations were not statistically related to the soil characteristics.
S Stefanovic, P A Cooper

Amine copper reaction with wood components: acidity versus copper adsorption
1997 - IRG/WP 97-30161
The bonding sites for copper in wood from CCA, as well as ammoniacal/amine based systems, has long been a topic of investigation. Both phenolic and carboxylic functional groups have been discussed as potential bonding sites for copper. However, no consensus on the adsorption mechanism has been realized. Thus, the selective adsorption of copper in southern yellow pine from ethanolamine-copper solutions and its correlation to wood acidity is currently being investigated. The wood acidity has been determined by acid/base titration, and is due to more than one type of acidic group. The acid(s) can be removed by thermal treatment or extraction techniques, and, interestingly, the selective adsorption of copper was observed to track the presence of particular acid functionalities. The preferential adsorption of copper and the mechanisms behind such will be discussed.
S M Thomason, E A Pasek

Moisture Adsorption Behaviour of Rubber Wood Decayed by Brown and White rot Fungi
2005 - IRG/WP 05-40306
Moisture adsorption behaviour of rubber wood blocks decayed by each brown rot and white rot fungi was studied. The adsorption isotherms of decayed wood were compared with the isotherm of undecayed wood. The wood decayed by brown rot adsorbed less moisture as compared to sound or undecayed wood at all humidity levels. No significant difference was observed in adsorption behaviour of white rot decayed and un-decayed wood. The adsorption isotherms were analyzed using Hailwood- Horrobin model of water sorption in terms of water of hydration of wood (Mh) and dissolved water (Ms) corresponding to monolayer and multilayer adsorption respectively. The analysis suggested a significant reduction in both Mh and Ms values for brown rot decayed rubber wood suggesting the loss of number of adsorptive sites by the decay. A good agreement between experimentally obtained adsorption isotherms and with those obtained using model.
S S Chauhan, H C Nagaveni

Measurement of electrokinetic potential to evaluate adsorption of quaternary ammonium salt
1991 - IRG/WP 3672
Measurement of z-potential in the wood treated with preservatives is suggested as a method for determination of the adsorption of preservative to wood. It has been found that measurement of z-potential of wood treated with quaternary ammonium salt type preservatives can be a useful method to determine the adsorptives phenomena of preservatives and by which there is a remarkable differences in the adsorbed condition with the components of preservatives concentration of treating solution, treating time and the elapsed time for streaming potential measurement in wood treated with quaternary ammonium salt type, there were differences in values of z-potential against that of untreated wood with a difference in chemical formula of preservatives, addition of chemicals for polymerization and concentration of treating solution. In case of the wood treated with quaternary ammonium salt with silicon, the treating time to reach the completly adsorbed condition of preservatives was about 3-5 minutes in concentration of below 0.75% and was about 15 minutes in above 1.5%. On the other hand, in adsorption of benzalkonium chloride, it took 15 minutes of adsorbing time in below 0.75% and 7.5 minutes in above 1.5%. Regardless of the extension of elapsed time for measuring, the constant values in z-potential was not obtained in wood treated with quaternary ammoniusalt with silicon, this result was attributable to leaching of preservatives. Whereas, for measurement of wood treated with benzalkonium chloride, it took the measuring time of 15-20 minutes to obtain constant values which mean a stable condition in adsorption.
Yeong Suk Kim

Moisture adsorption isotherms of wood studies using a dynamic vapour sorption apparatus
2009 - IRG/WP 09-20398
Five types of wood including two Malaysian hardwoods acacia mangium (Acacia mangium) and sesenduk (Endospermum malaccense), two temperate softwoods, Sitka spruce (Picea sitchensis), radiata pine (Pinus radiata) and Accoya (commercially modified wood) were studied to determine their moisture sorption behaviour using a Dynamic Vapour Sorption (DVS) apparatus. The isotherm plot for each species tested showed differences in the adsorption and desorption behaviour. The modified wood Accoya had the lowest Equilibrium moisture content (EMC). The hysteresis of Accoya also exhibited the lowest value between the adsorption and desorption isotherms. The data was also analyzed using the Hailwood-Horrobin (HH) model for isotherm fitting and determination of monolayer and polylayer moisture content. Comparison on the number of accessible OH groups in the monolayer as determined by the HH theory did not correspond with that determined using Rowell’s method for any of the samples.
J Zaihan, C A S Hill, S Curling

Adsorption of ionic liquids by Scots pine wood (Pinus sylvestris L.) and beech (Fagus sylvatica L.): equilibrium and kinetic modeling
2010 - IRG/WP 10-20447
In this paper methods for the adsorption study of quaternary ammonium-based ionic liquids on Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L) are presented. Kinetic and equilibrium adsorption of compounds were evaluated. The equilibrium data fitted very well to the Langmuir adsorption models. The highest correlation coefficients determined from the pseudo-second order kinetic model confirm the key role of chemisorptions in the process of thickening of ionic liquids on the wood surface. The bonding identification of the ammonium nitrates into the Scots pine and beech wood was carried out using IR spectroscopy.
J Zabielska-Matejuk, A Stangierska, M Kot

Adsorption of ACQ components in wood
2010 - IRG/WP 10-30522
To investigate the chemical adsorption capacity of copper-monoethanolamine (Cu-Mea) components on wood, the Na+ cation exchange capacity (CEC) of red pine (Pinus resinosa Ait.) was determined and compared to the adsorption capacity of free Mea and Cu-Mea complexes. The CEC increased with increasing pH. Free Mea adsorption as a function of pH followed the sodium adsorption curve except at pH over 9, when it exceeded the CEC. Cu-Mea adsorbed up to the CEC at pH 9.0-9.5 apparently as Cu(Mea)+, whereas the complex in solution is predominantly of the form Cu(Mea)2+. For the quaternary ammonium compound, alkyl dimethyl benzyl ammonium chloride (ADBAC) adsorption isotherm showed two different adsorption mechanisms into wood: ion exchange reaction at low concentration and hydrophobic interaction at high concentration. ADBAC adsorbed at solution concentrations below a critical concentration (hemi-micelle concentration) had high leaching resistance while ADBAC adsorbed into wood at above the critical micelle concentration (CMC) had low leaching resistance. The CMC decreased with addition of Mea and Cu-Mea. The anion, Cl- of ADBAC was only adsorbed at solution concentrations above the CMC and was easily leached out. The adsorption capacity of ADBAC into wood by cation exchange reaction did not achieve the cation exchange capacity (CEC) of wood. However, the total adsorption of ADBAC and Cu achieve the CEC of wood in the presence of copper amine, and ADBAC competes with copper to occupy the same sites in wood.
Myung Jae Lee, P Cooper

Adsorption boundary curve influenced by step interval of relative humidity investigated by Dynamic Vapour Sorption equipment
2011 - IRG/WP 11-40547
The adsorption of water vapour from dry conditions by Norway spruce sapwood has been investigated using Dynamic Vapour Sorption (DVS) instrumentation. This equipment allows a fast and easy data acquisition as well as enables detailed studies of sorption properties using very small sample masses. In this study, particular focus was paid to the effect of step size on the sorption isotherms. Furthermore, the influence of relaxation of swelling stresses was investigated. This was done by having relative humidity (RH) histories with different RH step sizes and by introducing prolonged periods of conditioning at constant climate. The adsorption isotherms constructed on the basis of acquired sorption data was not significantly influenced by the differences in relative humidity (RH) histories. Thus, for practical purposes a stability criterion of 0.002 %/min was found to be adequate for acquiring wood adsorption isotherms using sample masses around 20-45 mg. The different RH histories did, however, affect the sorption kinetics. The sorption proceeds slower if the sample was conditioned at constant climate for a prolonged period before being exposed to another RH level. This indicates that relaxation of swelling stresses affects the sorption kinetics. During the initial phase of adsorption after changing RH, the moisture uptake was found to be linear with the square-root of time. From sorption and swelling kinetic theory the diffusion coefficient of the wood cell wall could be estimated based on data from the initial phase of the adsorption processes. The diffusion coefficient was found to decrease with increasing RH and to be independent of step size, as expected.
E Tang Engelund, M Klamer, T Mark Venås

Activities of moulds on wood as a function of relative humidity during desorption and absorption processes
2013 - IRG/WP 13-10794
Three different types of indoor moulds: Penicillium brevicompactum, primary colonizer; Alternaria tenuissima, secondary colonizer and Trichoderma harzianum, tertiary colonizer, grown on wood were measured for their activities under different relative humidity levels. The activities were measured by isothermal calorimetry. The activities of the moulds changed with the change of the relative humidity levels. The optimal relative humidity levels are different for these three moulds. The mould activities were also different from desorption to adsorption processes under the same relative humidity levels. This might be caused by the moisture hysteresis properties of wood. Therefore, besides of relative humidity, water availability also plays an important role for mould growth. Such information should be taken into account for modelling mould behaviour on building materials.
Yujing Li, L Wadsö

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