Recently research on volatile organic compounds (VOCs) has been conducted and published in journals of research societies such as Architectural Institute of Korea, Society of Air conditioning and Refrigeration Engineers of Korea, Korea Institute of Ecological Architecture and Korean Society of Living Environment System since the late 1900's in Korea. This study reviews all articles on VOCs research in these four journals to produce a bibliography and determine the research trends. All articles are classified into three different topics as follows ; 1) Laboratory research on building materials and field research on the concentration of pollutants, 2) Kinetic properties of pollutants and strategies for their control, and 3) Hazardous effects of IAQ on occupants. It was found that much research on VOCs has been conducted since 2005, especially in the above topics 1) and 2). Research about topic 3) has not been carried out as much as about topics 1) and 2), because it has only been begun very recently.

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Aged baulk timber in a historic building of Fukushoji-temple (national cultural property) was investigated to estimate the extent of deterioration of aged timbers. The samples were all Pinus densiflora, but installed in different years, approximately 1500, 1662 and 1836. They were of similar rank order and built in similar circumstances. The timbers had insect damage by Nicobium hirtum. Soft X-ray transfer imaging and density measurements revealed that the insect damage was more severe with increasing age. To discuss change by aging of wood substance itself, insect-damaged parts were eliminated and undamaged parts were investigated : the oxidization temperature and Young's modulus in L-direction seemed to be higher for the present than the aged wood, but clear relation with aging was not detected. X-ray diffraction analysis of undamaged part revealed that relative cellulose crystallinity of aged samples was similar to or rather higher than that of the present sample. The crystallinity was negatively correlated with the Young's modulus. The holocellulose content of the undamaged parts seemed to decrease with aging. These facts imply that slight changes of chemical components other than crystalline cellulose might occur by aging. Comprehensively, in this case, the practical issue was insect damage, rather than deterioration by aging.

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To establish the cutting performance and tool wear characteristics of cemented carbide tools with clearance faces coated with CrN, end-grain surfaces of white oak were milled with a cutting diameter of 134 mm, with two tools coated with CrN to a thickness of 5.5 (UP1) and 11.5μm (UP2) and at a spindle speed of 6000 rpm. Cutting edge profiles, edge wear and machined surface roughness were measured at some feed lengths up to 20 m and compared with those for two uncoated tools of high speed steel (HSS) and of cemented carbide (UH). For HSS and UH the tool edge radius increased with the feed length and the machined surface was quite poor at a feed length of 20 m. On the other hand, for UP1 and UP2 the cutting edges remained sharp and the machined surfaces were always smooth, although the coating layers were worn strongly at localized parts along the cutting edge and the wear width on the clearance face increased rapidly at the beginning of cutting test. The cutting edge radius for UP1 and UP2 at a feed length of 20 m was about 1.5μm, which was ten or three times smaller than that for HSS or UH, respectively.

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In the last report, we proposed an analysis method for the deformation and shear resistance of mortar walls. This report tried to improve the analysis method discussed before by means of providing a new analysis method for strength properties of joints made with staples and lath. We carried out wall racking tests on the lath mortar wall and examined the fracture behavior of mortar and lath. Then we compared the resulting calculated value based on the improved analysis method and the measurement value based on the wall racking test. As the result, it was proved that the fracture condition of mortar walls was predicted by the application of the improved analysis method. Therefore, it seems to suggest that application of this method will enable estimation of the fracture condition of joints in each stage of shear deformation of mortar walls.

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Friction between timber and timber or other structural materials plays an important role in actual mechanical behavior of timber constructions. To consider the effect of friction in structural design of timber constructions, frictional coefficients between the structural materials used should be evaluated as the first step. In this study, we conducted experimental measurements of frictional coefficients between structural timber and some structural sheet materials. We prepared planed softwood timber specimens and some typical structural sheet materials : softwood plywood, hardwood plywood, OSB and MDF. We also prepared “volcanic silicates fiber reinforced multi-layer board” and SS400 steel. Static and dynamic frictional coefficients between timber and these materials were measured for every combination of grain or direction of greater strength. The obtained static fictional coefficients ranged from 0.2 to 0.4 among all combinations of materials and slip directions, and the relative order was MDF > Softwood plywood > Hardwood plywood > volcanic silicates fiber reinforced multi-layer board > steel > OSB. The ratios of dynamic frictional coefficients to static frictional coefficients ranged from 0.6 to 0.9, and the relative order of the average values was volcanic silicates fiber reinforced multi-layer board > steel > hardwood plywood > OSB > Softwood plywood > MDF. Test results showed negative correlations between specific gravity of timber and static/dynamic frictional coefficients among all combinations of test materials and slip directions. Frictional coefficients perpendicular to the grain of timber were found to be larger than those parallel to the grain. Although the surface grain of plywood showed a similar effect, we found only a little difference between both directions. The effect of strand orientation of OSB was almost negligible.

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Phospholipid fatty acid (PLFA) analysis was used to estimate the changes in microbial community structure during decompositions of sugi and konara wood samples buried in soil of sugi plantation or broad-leaved forest. As the result of cluster analysis, the microbial community structure estimated by PLFA composition was classified in two groups by the wood species of sample, not by the forest vegetation. In konara wood samples, the index of fungal biomass measured as PLFA of fungal origin was held constant at a higher level, and the amount of gram positive bacterial biomass increased as the decay proceeded. The amount of each microbial biomass was positively correlated with the degree of wood decay. In sugi wood samples, PLFAs chosen as indexes of fungal, gram positive bacterial and actinomyces groups increased during wood decay, but no correlation was found between the amount of fungal biomass and the degree of wood decay. These results suggested that bacterial and actinomyces groups other than the fungal group would play a significant role in the decay of sugi wood samples.

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