tudents need practical and experiential activities to learn effectively about housing functionalityand appropriate housing planning and management in high school home economics classes. In this study, we focus on wooden flooring in the living room and develop five simple performance tests. The test results showed that the soy sauce and ink stain resistance tests revealed differences in functionality depending on whether the surface was coated, whereas the steel ball drop test depended on whether the surface was impregnated with plastic. The JIS test was simplified as a pencil hardness test. The results of the steel ball movement test showed a difference in scratch resistance between the tested flooring types. Both tests are easy for students to administer in high school home economicsclasses without needing special equipment.
Hinoki (Chamaecyparis obtusa) is one of the most important tree species for plantation in Japan, which is used as building materials of the highest quality and accounts for 25% of the artificial forests. For sustainable plantation of hinoki, the establishment of mass propagation methods is needed. We attempted to develop a plant regeneration system by adventitious buds formation from callus obtained from mature zygotic embryos. Embryos were cultured on modified Campbell and Durzan medium containing 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP) and green calli were then induced. Green calli were transferred from dark condition to light condition, and adventitious buds and multiple buds formation were observed. Shoot elongation was observed in the culture of shoot tips from multiple buds on hormone-free medium, and then rooting was observed on all media containing 0, 3 or 6 & micro;M indole-3-butyric acid (IBA). After developed plantlets had been transplanted to the soil, normal growth was observed, indicating successful plant regeneration.
Micromachining using a short-pulse ultraviolet (UV) laser was applied to drilling holes into wood. In wood processing, the wavelength dependence on processing efficiency and its form was significant, and the superiority of UV wavelength (355 nm) laser was found. By applying the extremely high aspect ratio holes obtained by this as laser micro incisions (LMI) various studies have been conducted, such as adding functions to the surface and improving the permeability of liquids. This paper first summarizes the research examples of laser processing of wood and its history, explains the differences in equipment and the effects of these differences on the processing form, and then introduces application examples of LMI and looks ahead to its possibilities.
Strandboards were manufactured and their property was tested under several combinations of strand thickness and resin content in order to determine the effects of strand thickness and resin content on the mechanical and physical properties of the boards. It was shown that strand thickness and resin content had statistically significant effects on bending properties, internal bond strength, and water resistance. Bending properties and water resistance were found to be superior with thinner strands and higher resin content, while internal bond strength was found to be higher for thicker strands with lower resin content and for thinner strands with higher resin content. Statistical analysis confirmed that bending properties were more affected by strand thickness and thickness swelling was more affected by resin content. In terms of bending properties, modulus of rupture improvement due to strand orientation was found to be more pronounced for thicker strands.
In this study, dust explosion of coal or charcoal mixed with wood powder was evaluated using a 1.2 L Hartmann apparatus. For particles smaller than 53 mu m, the minimum explosion concentration (MEC)of wood dust and coal was 40 g/m3, indicating a high risk of dust explosion. Charcoal did not explode above 1000 g/m3, it was considered to be caused by the carbon and volatile matter contents. For coal mixed with wood powder, the minimum ignition energy (MIE) of 25 wt% wood was the lowest. Coal was considered to act as a dispersant for wood powder, as the degree of cohesion in 25 wt% wood mixture was almost the same as that in coal. For charcoal mixed with wood, the both MEC and MIE values were decreased depending on the wood powder ratio.
Oaks(Quercus spp.) have a visual characteristic in which broad rays (BR) appear clearly. BR occasionally creates unique band-like patterns, silver grain (Torafu), which cross axial tissues on the quarter-sawn surface and are related to an important visual factor. Therefore, the aim of this studywas to extract the patterns formed by BR and classify individual pieces using the BR patterns. First, we prepared the photographic conditions that could document the BR clearly. Then we applied image processing, including percentile binary and anisotropic high-pass filter, to convert the BR regions into binary images. The average extraction accuracy of this method was 96.4% using 20 samples. After measuring some geometric feature parameters on the images and summarizing them using principal component analysis, it was suggested that three feature values-the index of lateral band size against the axial direction, the index of vertical length along the axial direction, and the number of blobs-are important for documenting the BR shapes. Finally, 180 samples were classified into five clusters,"inconspicuous BR", "diagonal pattern", "vertical long thin pattern", "large Torafu pattern", and "Torafu pattern", based on the features, confirming that the qualitative classification was carried out effectively.
The recent global pandemic of the COVID-19 infection has caused significant impacts on the improvement of living environments. When utilizing Japanese cedar (Cryptomeria japonica) as building materials (such as interior finishing materials or structural materials), various beneficial effects are known to be exhibited based on the physical and chemical properties of the wood. However, existing Japanese Agricultural Standards (JAS) pertaining to C. japonica have primarily focused on regulating the quality of wood surfaces and preservation treatments, lacking specific methods for analyzing the terpene content, which is essential when discussing the wood's good functionalities for human such as enhancing immune system function and promoting physiological relaxation. Therefore, we positioned the standardization of analytical methods for functional components derived from C. japonica as an effective means to enhance the added value. In this study, we established a JAS-compliant analytical method for functional component analysis of C. japonica wood using gas chromatography-mass spectrometry
This study aimed to collect fundamental data to understand the strength characteristics of aged timber and to explore methods for estimating its mechanical properties. This study was conducted using removed timber approximately 500 years old from Josho-ji Temple in Onomichi City, Hiroshima Prefecture. The subjects of the study were Japanese red pine (Pinus densiflora) and Japanese cypress (Chamaecyparis obtusa). Dynamic Young's modulus measurements and strength tests on full-size timber and defect-free small specimens were performed. A comparison of the bending and longitudinal compression strength of full-size timber with reference values for each mechanical grading category showed that a higher Young's modulus increased the proportion of specimens falling below the reference strength. Positive correlations were observed between the dynamic Young's modulus and static Young's modulus, as well as between the dynamic/static Young's modulus and bending strength, suggesting that Young's modulus measurements are effective for estimating bending strength. For the defect-free small specimen tests, the bending strength of the aged Japanese red pine was 39.2% lower than that of new Japanese red pine, while the longitudinal compression strength showed no significant difference. The limited number of specimens makes the results for aged Japanese cypress inconclusive; however, its bending strength was 29.5% higher and longitudinal compression strength 53.5% higher than in previous studies on Japanese cypress timber. The high strength of aged Japanese cypress may be attributed to the narrow annual ring width. These findings are expected to serve as fundamental data for future assessment of aged timber and provide useful information for the appropriate reuse of dismantled structural wood.
The authors are involved in the standardization of the JAS method that will enable sawmillers and builders to determine the content of functional low-molecular components in dried solid cedar wood, in order to further evoke the demand for domestic cedar wood (Cryptomeria japonica). The solvent extraction-gas chromatography-mass spectrometry (GC-MS) method developed by the authors can clarify the content of sesquiterpenes, which are thought to contribute to the functional properties of cedar wood (such as improved sleep quality, relaxation, antibacterial and anti-mite effects). In this paper, the validity of the method was confirmed in a single laboratory according to international guidelines. The evaluation parameters were selectivity, lower limit of detection, lower limit of quantification, calibration curve, accuracy (recovery rate) and precision (concurrency, intermediate precision). Results for recovery rate and accuracy were obtained. Peak resolution, linearity of the calibration curve and lower limits of detection and quantification were also confirmed, and were judged to be valid analytical method.
his study explores the significance of converting public buildings to wooden construction and employing wooden interiors when considering the expansion of wood utilization. It also examines how forest coverage and the presence or absence of forestry-related departments impact the conversion of main government buildings to wood construction in municipalities, along with the key issues related to this transition. The targeted municipalities were classified into "Wooden", "Wooden interior", and "Non-wooden" groups. According to the results, 10.4% municipalities fell into "Wooden" group, 83.2% into "Wooden interior", and 6.4% into "Non-wooden". A comparative analysis indicated that municipalitieswith higher forest coverage and more forestry-related departments were more inclined to adopt wood construction for their main government buildings. A quantitative text analysis of the minutes of committee meetings and other meetings related to the construction of the main government building highlighted issues such as the time required to procure local timber, earthquake and fire resistance,seismic isolation performance of wooden structures, and construction costs, although the use of localtimber is expected from the perspective of forestry promotion when constructing main governmentbuildings.
In drift-pin joints with slotted-in steel plates, a staggered arrangement of drift pins can potentially reduce the joint size. Sufficient staggered widths and fastener spacings that prevent brittle behavior under shear loading must be clarified. In this study, a double-shear test was conducted under various staggered arrangements of drift pins, primarily focusing on the ductility. Ductile behavior was observed when the fastener spacing was six times the fastener diameter or greater. Furthermore, brittle behavior was observed at five times the diameter under conditions with small staggered widths. When the spacing was 3.5 times, all the configurations exhibited brittle behavior regardless of the staggered width. Additionally, an attempt was made to numerically express the arrangement conditions using ellipses in a planar coordinate system, and a simplified method was proposed to ensure the deformation performance. These findings are valuable for joint designs.
The pre-cut lumber industry is a critical node in the distribution of lumber for construction and plays a significant role in driving demand for wooden products. However, it is categorized under the miscellaneous wooden products sector in the existing national input-output table(ex-IO) at present. In this study, based on mail surveys, interviews, and statistical data, we developed an extended input-output table suitable for analyzing wood use by establishing a pre-cut lumber sector and a new miscellaneous wooden products sector (new-WP) within the ex-IO framework. As a result, most of the input in the pre-cut lumber sector was lumber, and the ratio of gross value added accounted for 34.4% of total input. On the other hand, the input of the new-WP was diverse and not limited to lumber, and the ratio of gross value added accounted for 59.1% of total input. It shows that mechanization or automation in the pre-cut lumber industry had advanced like other lumber industries.
Activated carbon made from Japanese ceder(Cryptomeria japonica) was processed into samples with different yields by changing the activation conditions, and electric double layer capacitors were manufactured using the activated carbon. It was found that specific surface area, micropore volume and mesopore volume increases with decreasing carbon yield. Moreover, each coefficient of determination showed a high value. The micropore and mesopore volume plots of activated carbon move to the region of larger pores and the pores of around 0.6 to 0.7 nm can be related to the initial value of the capacitance. In addition, compared with commercial activated carbon, there is a similar capacitance and low internal resistance in activated carbon from Japanese ceder, which is analyzed by durable examination
To clarify the physiological characteristics of the new variety ON206, external factors affecting the nutritional growth of mycelia were investigated, particularly focusing on the initial pH, nutrient composition, and effect of light or mycelium. The optimum initial pH was 5.6, md growth was possible in a wide range of pH, from 4.0 to 8.9. As a carbon source, soluble starch showed the best growth, and the maximum mycelial volume was observed at a concentration of 15.0%. As a nitrogen source, yeast extract showed the best growth, with an optimum concentration of 2.0%. Organic nitrogen tended to be more effective for mycelial growth than inorganic nitrogen. Light affected mycelial growth of ON206. In particular, blue light tended to suppress mycelial growth and increase mycelial density. This study established the basic culture characteristics of the new variety ON206 and its nutrient requirements and photosensitivity tended to be similar to the mother strain, Pleurotus nebrodensis .
