Fungal decomposition of wood severely affects the soundness of timber constructions. The diagnosis of wood decay requires direct observations or sampling by skilled experts. Wood decay often occurs ...in obscure spaces, including the enclosed inner spaces of walls or under the floor. In this study, we examined the ability of machine olfaction to detect odors of fungi grown on common construction softwoods to provide a novel diagnostic method for wood construction soundness. The combination of a simple device equipped with semiconductor gas sensors (gas sensor array) and multivariate analysis discriminated a fungi-related odor from control odor without instrumental analysis (e.g., gas chromatography). This method is often referred to as machine olfaction or electronic nose. We measured the odor of wood test pieces that were infected with
Fomitopsis palustris
or
Trametes versicolor
and sound test pieces using a gas sensor array. The sensor responses of the specimens showed different patterns between the inoculated and control samples. Each specimen class formed independent groups in a principal component score plot, almost regardless of wood species, fungal species, or cultivation period. This method provides a new decay diagnosis method that is cost-effective and easy to operate.
Ammoniacal copper quaternary (ACQ) wood preservatives contain benzalkonium chloride (BAC) as the active ingredient. BACs in commercial ACQ products comprise mainly benzyldimethyldodecyl ammonium ...chloride (C12 homologue) and benzyldimethyltetradecyl ammonium chloride (C14 homologue). Previously, we developed solid-phase extraction (SPE) on Oasis MCX as a strong cation exchanger, followed by liquid chromatography with UV detection (LC-UV) for the quantitative determination of C12 and C14 homologues in treated wood. In this study, the previous method was modified. Samples were cleaned up before analysis, and a weak cation exchanger, Oasis WCX, was employed. C12 and C14 homologues were added to 500 mg of powdered wood samples of Japanese cedar (Cryptomeria japonica), Japanese larch (Larix leptolepis), Sakhalin fir (Abies sachalinensis), and Yezo spruce (Picea jezoensis) at levels of 10, 1, and 0.1 mg g-1 wood. Treated wood samples were then extracted with HCl/EtOH, and the extracts were filtered and subjected to SPE with Oasis MCX and Oasis WCX, followed by LC-UV analysis. Recovery rates ranging from 90% to 111% were achieved for SPE using both cation exchangers for active ingredient concentrations of 0.1–10 mg g-1.
Different leaching media composed of watersoluble extracts from Sakhalin fi r, Japanese cedar, and Japanese larch heartwoods and of taxifolin were used to characterize leaching of the C12 and C14 ...homologues of benzalkonium chloride from treated wood. The leaching medium of Sakhalin fi r extract moderately accelerated the leaching rates of the two homologues. Japanese cedar extract accelerated the leaching of the C12 homologue at a similar rate and that of the C14 homologue at a higher rate. Japanese larch extract remarkably accelerated the leaching rates of both homologues, particularly that of the C14 homologue. Thus, the leaching rate of the C14 homologue was higher than that of the C12 homologue with the Japanese cedar and larch extracts. The media of taxifolin, a major phenolic extractive of Japanese larch, preferentially accelerated the leaching rate of the C14 homologue. The amounts of phenolic compounds in the different leaching media were in the following order: Japanese larch > Japanese cedar > Sakhalin fi r. These results indicate a relationship between the amount of phenolic compounds and the leaching rates of the two homologues.
Experiments were carried out to determine the leaching mechanism of benzalkonium chloride (BAC) from treated wood in soil. Wood specimens were treated with C12, C14 and C16 BAC homologues and exposed ...to soil or aqueous solutions containing oxalic acid, sodium oxalate, hydrochloric acid, sodium chloride or sodium humate. The leaching rates of the homologues in soil were close to each other and all higher than in distilled water. The order of the rates in soil (C12 ≈ C14 ≈ C16) was different from that in distilled water (C12 > C14 > C16). The leaching rates of the homologues in the acidic solutions and their salts solution were also higher than in distilled water, and the order of the rates was the same as in distilled water. The aqueous solution of sodium humate also accelerated homologue leaching but resulted in an order of C16 > C14 > C12. The BAC leaching acceleration mechanism by humate was thought to be different from the mechanisms of acids and their salts and plays an important role in the leaching behaviour of BAC in soil.
This study aimed to investigate the performance of joints in decayed lumber made with a fastener with multiple connectors. We conducted shear resistance tests of a hold-down connected to Sakhalin fir ...(Abies sachalinensis) lumber exposed to a brown-rot fungus (Fomitopsis palustris). This hold-down was connected with seven screws. We measured depth of pin penetration with a Pilodyn in the main members after shear tests. We concluded that joint performance when the main member decays is not much reduced for fasteners with multiple connectors when compared to those with a single connector. Depth of pin penetration showed negative correlation with maximum, yield, and ultimate shear resistance. Yield shear resistance of multi-screw joints connected to decayed lumber could be calculated safely by the European Yield Theory.
Benzalkonium chloride (BAC) is the active ingredient of ACQ-1, one of the most widely used wood preservatives in Japan. BAC in ACQ-1 comprises homologues with different alkyl chains: C12 comprises ...74%; C14 26%; and C16 < 1%. To clarify the leaching characteristics and the factors affecting the leaching of BAC homologues, wood specimens treated individually with the C12, C14, and C16 homologues were used in a leaching experiment with distilled water (DW) and artificial sea water (SW). The leaching rates of the BAC homologues were accelerated by the SW, and the order of the leaching rate in both DW and SW was C12 > C14 > C16. When the specimens were treated with a mixture of two of the three homologues, the leaching rates of the C14 and C16 homologues from specimens treated with a solution containing C14 and C16 were lower than that from specimens treated with a solution containing the C14 or C16 homologue together with C12. From the adsorption isotherm of the homologues it is assumed that the formation of BAC aggregates on the treated wood is related to their leaching. BACs consisting of mainly C14 and C16 are thought to be suitable for reducing leaching, particularly in marine usage.
Ammoniacal copper quat (ACQ) compound wood preservative is comprised of copper and quaternary ammonium compounds with benzalkonium chloride (BAC) as the active ingredient. Solid-phase extraction ...(SPE) followed by liquid chromatography with ultraviolet detection (LC–UV) was developed for quantitative determination of BAC in treated wood. Five species of wood were used, Japanese cedar (
Cryptomeria japonica), Japanese larch (
Larix leptolepis), Yezo spruce (
Picea jezoensis), Sakhalin fir (
Abies sachalinensis), and western hemlock (
Tsuga heterophylla). BAC used in the present study was composed of 66% C12, 33% C14 and less than 1% C16. BAC was added to each wood species (500
mg) then extracted with HCl–ethanol (20
ml) and quantitatively determined with LC–UV (262
nm). Wood extractives from the heartwood of each species, except western hemlock, interfered with quantitative determination of BAC, but SPE with an Oasis MCX cartridge was effective in preventing this. Using the present methods, BAC homologue peaks were clearly confirmed without interference. Recoveries from wood ranged from 92 to 101% and the limit of quantitation was approximately 240
μg/g wood for the C12 and C14 homologues.
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