It is difficult for large molecular size organic liquids having a single hydrogen bond-forming group to swell wood. One of the reasons is probably because a long time is required to reach a swollen equilibrium at ordinary temperatures because of the steric hindrance of these liquids. In this study, wood was swollen by such liquids under higher temperatures than were used in previous investigations. The relationship between the degree of swelling and the liquids' characteristics was evaluated, leading to the following conclusions: Wood can be swollen by some liquids with molecular volumes above 100ml/mol. High temperature conditions resulted in remarkable adsorption of bulky, large molecular-size liquids. Large swelling anisotropy was observed with high swelling liquids in the swelling processes. However, as the swelling approaches equilibrium, anisotropy becomes less for all liquids. Not only the hydrogen bonding property of the functional group but also the steric hindrance of these liquids, resulting from their size and the position of the functional group in the molecules, is relevant to the swelling of wood.

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The effects of forest management such as pruning and thinning on the relationships between logs and boxed-heart square timbers of sugi (Cryptomeria japonica D.Don) on both visual grades and strength properties were investigated. The logs cut down at control and managed forests and the boxed-heart square timbers sawn from the logs were used for visual grading, measuring modulus of dynamic elasticity using frequency (E_fr), and full-sized bending tests. The results are summarized as follows: The results of visual grading showed that for control forests second grades of boxed-heart square timbers sawn from third grades of logs accounted for 65%, whereas for managed forests first grades of timbers sawn from first grades of logs accounted for 32% because the influence of knots became small by pruning. The relations between E_fr of logs and the modulus of elasticity (MOE) or the modulus of rupture (MOR) of boxed-heart square timbers showed that there were significant differences in the intercepts of regression lines between control and managed forests. MOE correlated highly with E_fr rather than with the presence of knots on the timber surfaces or average annual ring width. MOR correlated highly with the presence of knots on the timber surfaces, which proved that pruning was an important factor for forest management.

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To measure fracture toughness in both mode I and mode II, possibility of successive measurement tests with a single specimen was examined. The DCB test for G_Ic measurement and the 3ENF test for G_IIc measurement were adopted because the shape of these specimen is the same. Effects of crack length and test order on fracture toughness were examined. Stable fracture toughness was achieved with both the DCB tests and the 3ENF tests when crack length was 100mm. By including the influence of shear deflection in the corrected crack length, the influence of shear was removed from fracture toughness in mode I. But in mode II, the corrected crack length and fracture toughness have to be calculated with the equation considering shear deflection. Fracture toughness obtained by the succeeding test tends to be less than that obtained by the foregoing test.

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We investigated the amount of dimension change and the shape variation in densified wood after carbonization. The variables in the study included specimen length, specimen type (Japanese cedar (Cryptomeria japonica D.Don) heartwood or sapwood), compression ratio, temperature and time of pre-heat treatment, and the shape of the exhaust slit on the specimen for generating pyrolysis gas under carbonization. Heartwood specimens with a high compression ratio and/or a long length showed intensified degree of shape variation after carbonization, such as splitting and differences in the coefficient of shrinkage in radial direction between the edge and center positions. These results occurred because the heartwood and highly-densified wood had poor gas permeability into the lumen due to the deposition of heartwood extracts on the pit and airflow narrowing by buckling of the cell wall. When the pyrolysis gas was not discharged outside the wood under carbonization, the high-pressure gas into the lumen affected the degree of shape variation and the finished density of the charcoal. The shape stability of the charcoal can be controlled by using pre-heat treatment and slit processing, because the difference in the coefficient of shrinkage in radial direction between the edge and center positions after carbonization decreased with heavier pre-heat treatment and shorter pitch distance of the exhaust slit.

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The effect of chromium nitride (CrN) coating on the cutting performance and wear characteristics of high-speed steel finger-cutters was examined. Fingers of 14.7mm length and 3.8mm pitch were produced on the end grain surfaces of Douglas-fir using a 170mm diameter cutter with two insert blades, coated only on the clearance face (HP) and uncoated (HSS), at a spindle speed of 5000rpm and a feed speed of 2.5m/min. The wear of the cutting edge was measured at total feed lengths of up to 1000m for HP and 300m for HSS. Furthermore, machined surface roughness, working accuracy, and bending strength of finger-jointed specimens were evaluated for specimens of spruce, which were cut with two insert blades at the same total feed lengths as for the edge wear measurements. For HSS at a total feed length of 300m, the cutting edge radius was 21.1µm and the machined surface and working accuracy were very poor. For HP at a total feed length of 1000m, the cutting edge radius was only 5.3µm and the bending strength of jointed specimens decreased slightly from that for the total feed length of 0m but was still good enough for practical uses. It was also found that there was a good linear relationship between bending strength and cutting edge radius irrespective of the kind of tool.

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Activated carbon (AC) was prepared from coconut shell char by two-step activation using KOH followed by CO₂ or steam. Greater BET surface area and wider pore AC could be obtained by the two-step activation compared with the single step activation by KOH. Steam activation produced greater pore development, especially of meso and macropores, than carbon dioxide activation. For the KOH and steam sequential activation, a BET surface area of 3111m²/g and a meso and macropore surface area of 1744m²/g could be achieved with the two-step activation of KOH at 800°C and then steam at 900°C for 60min each. Adsorption of nitrobenzene and acetaminophen onto prepared ACs was examined in aqueous solution. The amount of nitrobenzene adsorption was proportional to the surface area, the pore volume, and the meso and macropore volume. The AC prepared by the two-step activation described above could have 3 and 2 times greater amounts of adsorption of nitrobenzene and acetaminophen, respectively, than commercially available ACs.

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A tree of Picea koyamae, a threatened conifer felled by a typhoon, was obtained and various properties of its wood were investigated to understand the value for lumber. Measurements were taken of grain angle and color. Mechanical properties were measured with static bending, impact bending and compression tests. Since Picea spp. is used for musical instruments, vibration tests were also undertaken. The results were as follows: 1) The grain was an S-helix, and the grain angle decreased toward the bark. 2) Mechanical properties did not change remarkably, but they increased partly toward the bark. Mechanical properties around the pith differed from those in other parts. 3) Mechanical properties were similar to those of other Picea spp. except the compressive Young's modulus in the R-direction. 4) Brightness index was high. 5) Although Picea koyamae has superior properties among those mentioned above, many knots exist at intervals of 300 to 400mm. Hence, pruning is very important.

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Modulus of elasticity (MOE), modulus of rupture (MOR) in static bending and air-dried density were investigated for todomatsu (Abies sachalinensis) plus-tree clones. A total of 42 sample trees of 14 plus-tree clones were used. For analyzing these properties, the xylem was classified into two groups: core wood (up to the 17th annual ring from the pith) and outer wood (from the 18th annual ring to the bark). Microfibril angle of the S₂ layer in latewood tracheids (MFA) was investigated using 21 sample trees of 7 plus-tree clones which were selected from static bending test sample trees. Significant relationships were recognized among air-dried density, MOE and MOR. The radial variation pattern of MFA, especially near the pith, was different among clones. The results of relationships among MFA, air-dried density and MOE showed that MOE was affected by air-dried density rather than by MFA. Significant relationships were observed between core wood and outer wood in air-dried density, MOE and MOR. The results obtained suggested that these traits could be estimated at an early stage of growth.

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