Changes in the moisture content of Japanese cedar (Cryptomeria japonica D. Don) green wood for columns with the dimensions of 110×110×1000 mm during drying in environments of over 100°C and 1 atm were measured. Temperature and mass were measured in an airtight chamber. The set temperature and gauge pressure ranges were 110 to 140°C and 0.01 to 0.24 MPa, respectively. The experimental measuring system was suitable for understanding whether or not the mass of the specimens was stable. The change in the temperature of a specimen was roughly divided into 4 ranges. At lower temperatures and pressures, the equilibrium moisture content was similar to previous estimates and measurements, while at higher temperatures and pressures it differed from the previous values.

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SP adhesive, consisting of styrene-butadiene rubber (SBR) and polyethylene glycol (PEG), has been developed and used to make wood-based boards. This study aimed to improve the wood-based board properties by using an improved adhesive, ozonization and high mat moisture content. The internal bond strength (IB) was increased 1.44 times by the improved adhesive. It was also increased by ozonization. The optimum ozone charge was 0.5%, which improved the IB 1.35 times. When both the improved adhesive and ozonization were used, the IB was doubled and therefore the amount of adhesive could be reduced greatly. It is important to decrease the use of adhesive in order to encourage the use of boards because the adhesive is very expensive. The cost-saving of this adhesive more than offset the increase in cost of ozonization. Although the thickness swelling (TS) of this board was very high, the TS was improved greatly by increasing the mat moisture content.

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In order to understand the effect of the heat treatment on the dynamic viscoelastic behavior of water based polymer-isocyanate adhesive for wood (API adhesive), we investigated the most simplified model of the adhesive between polyvinyl alcohol (PVOH) solution and polymeric diphenylmethane diisocyanate (pMDI). Fourier transform infrared spectroscopy (FT-IR) was performed for estimating the residual isocyanate groups (NCO) and isocyanate derivatives to elucidate the reaction mechanism under the heat treatment conditions. The results are summarized as follows : (1) From DMA, a decrease of the storage modulus (E') appeared around 170°C in the sample heated below 140°C. When the treatment temperature exceeded 140°C, the samples exhibited a rapid increase in E' in the high temperature region, with a correspondingly significant chemical structure change. These results correspond with those of API adhesive. (2) The different chemical products and tendency of E' of API adhesive as compared to the PVOH-pMDI model after 2 hours of heat treatment indicates that the adding of styrene-butadiene copolymer latex (SBR) may affect progress of reaction of residual isocyanate.

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Bamboo carbon was prepared in N₂ flow for 2 hours at 500 °C with heating rates from 7 °C/min to 39 °C/min, resulting in a BET surface area ranging from 28 to 252 m²/g, respectively. For the next step, the pore structure of the bamboo carbon was developed by air oxidation at 280 °C for 2 hours, comparing it with coconuts shell char activation. A BET surface area of 460 m²/g could be achieved for the bamboo carbon, but only 230 m²/g for the coconuts shell char. When the air oxidation was conducted after de-ashing of the carbons with 1 mol/L HCl and 46% H₂F₂ solution, the surface area was as great as for the coconuts shell char containing ash. On the other hand, it was smaller for the de-ashed than for the untreated bamboo carbon. Based on the ash analysis, potassium was found to be the principal component for the bamboo carbon, but silicon, potassium and aluminum were detected in the coconuts shell ash. Examining air oxidation for mixtures of de-ashed coconuts shell char and potassium compounds (KOH, K₂CO₃, KNO₃, KCl), the highest BET surface area and total pore volume could be made by K₂CO₃ among the compounds. Hense, K₂CO₃ was estimated to play an important role for developing the pore structure of the bamboo carbon in the low temperature air oxidation.

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Increasing the utilization of wood on a long-term basis is considered one of the effective solutions in reducing greenhouse gases. Realizing its potential, construction of highly durable wooden houses has already been undertaken in the architecture field. On the other hand, in the civil engineering field, cases regarding the use of wood as a main structural element almost cannot be found. Here the authors consider driving wood piles into the ground as a countermeasure against ground liquefaction during an earthquake. This study discusses the durability of wood, which is one of the crucial subjects to be properly evaluated in order for wood to become an effective countermeasure material against liquefaction. The purpose is to solve some major misunderstandings concerning the utilization of wood. In this paper, first, changes in typical prescriptions for wood pile foundations in previous design specifications are compiled. Next, the durability of wood is discussed by referring to some past literature. In addition to the above, the case in which wood has acted as a countermeasure material against liquefaction during the 1964 Niigata earthquake is also given, followed by its effect on carbon stock.

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To understand the failure modes and shear strength of glulam composed of different species and lamina compositions, we manufactured three kinds of glulam, i.e., sugi, Douglas-fir and a composite of Douglas-fir and sugi, and subjected them to shear tests using the three-point bending method. As a result, we found that bending failure occurred in almost all of the sugi glulam specimens, and shear failure occurred in most of the Douglas-fir and composite glulam specimens. Various factors appeared to be involved with the failure modes, such as the lamina composition of the glulam, outermost lamina grade, compression and tensile strength of the outermost lamina, performance in compression perpendicular to the grain, and species and tissue structure. Calculations were made of shear strength using two kinds of equations : a homogeneous beam equation in which the material was considered homogeneous and failed in the neutral axis, and a composite beam equation. The effect of the position of shear failure was greater than the differences in shear stress of the various lamina compositions in the neutral axis. Therefore, not only lamina composition of the glulam, but also failure position in the cross section should be considered.

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