Middle-aged women face various stressors ranging from work-related to personal problems that brings out the sleep disturbance. In this study, we proposed essential oil prepared from the roots of Hinoki trees (Chamaecyparis obtusa) cultivated in Kagawa Prefecture as an alternative solution to sleep disturbance and proposed a home experiment to obtain realistic information compared with experiments in a laboratory environment. A single-blind cross over experiment has been conducted for 2 weeks with 12 women aged between 35 and 60 years (46 ± 6.72, mean ± SD) in each condition under Kagawa Hinoki’s root essential oil (KHREO) comparing with no scent situation (squalane oil) as a control. Physiological activity was measured by electroencephalography (EEG), and smartwatch, while psychological information was measured by the OSA sleep inventory MA. Volatile organic compounds in essential oils were analyzed using solid-phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS). This study revealed that the most abundant volatile compounds emitted from the essential oil were α-pinene, δ-cadinene, γ-cadinene, limonene, and α-muurolene. Results under visual analogue scale (VAS) show that KHREO was rated higher than the control condition in the categories of "scent strength", "scent liking", "bitterness", "relaxation", "comfort," "elegance", "nostalgia" and "woody scent". OSA sleep inventory MA also showed that participants under KHREO condition had better sleep quality especially in factor 1 (sleepiness at awakening) and factor 4 (fatigue recovery) after 13th day exposure. The EEG signal also showed increased slow-wave activity under KHREO which indicates the inducement of deep sleep from 7th day exposure. After using KHREO for 13 days, it was found that the frequency of awakenings during sleep, as detected by a smartwatch, decreased. This concluded that KHREO may play an important role in improving sleep quality by inducing deep sleep, reducing alertness during sleep and improvement from fatigue especially after 2 weeks of use.
A parametric study using a response surface methodology was conducted to investigate bamboo effect of feed rate, gas flow rate, and reaction temperature on the pyrolysis product distribution as well as the levoglucosan (LGA) yield during the formulated red mud (FRM) catalyzed pyrolysis of cellulose (CE). Box–Behnken design with three factors at three different levels was used. The factors used were the reaction temperature (350 °C, 400 °C, and 450 °C), the feed rate (50 g/h, 100 g/h, and 150 g/h), and the gas flow rate (5.6 L/min, 6.7 L/min, and 7.8 L/min). The significance of each factor was determined using the analysis of variance (ANOVA). The total liquid yield was significantly affected by the feed rate and the gas flow rate and it ranged from 30.0 wt
Eaglewood, also known as Aquilaria sinensis in China, is a type of resinous wood of the Aquilaria in the thymelaeaceae family with diversified values. In traditional Chinese medicine, it serves as a precious material for regulating qi and alleviating pain. Its unique aroma makes it a key ingredient in religious ceremonies and high-end incense. Its natural grain and rarity make it a highly collectible carved artwork. With its triple attributes of cultural heritage, medicinal health, and artistic investment value, eaglewood continues to release its irreplaceable and rare value. This article will explore the role of eaglewood in regulating sleep quality from the perspectives of medicine and art design. First of all, GC–MS was applied to detect the main chemical components released into the air after eaglewood incense sticks were lit. Then, the open field test, tail suspension test, forced swimming test, and collaborative hypnosis experiment systematically revealed that eaglewood has a calming effect and aids sleep, and pharmacological data were simultaneously converted into product design parameters. Finally through the combination of eaglewood and spatial aesthetic design, the study proposes the positive impact of the five senses on healing spaces, providing a new theoretical framework and practical path for designing sleep environments. GC–MS analysis revealed that the volatile components released into the air from burning agarwood incense sticks were mainly phenols (e.g., phenol, 2-methoxy-, phenol, 2,6-dimethoxy-) and terpenoids (e.g., Jasmone, E-, trans-2-Caren-4-ol,3-Caren-10-al). These compounds possess sedative, hypnotic and anxiolytic effects. On this basis, animal behavioral experiments further verified that the scented eaglewood can alleviate anxiety and fatigue in mice to a certain extent, and exhibits a significant sedative effect, which can significantly improve the sleep disorders of mice with insomnia. In addition, the unique aroma of eaglewood can create a multi-sensory healing experience through the art design of the space, redefining modern people's perception and expectations of sleep spaces.
Wildfire exposure can significantly reduce wood moisture content (MC), affecting wood quality and the feasibility of salvage logging. However, how fire severity interacts with tree physical characteristics to influence post-fire MC remains poorly understood. This study examined MC in white spruce, lodgepole pine, and trembling aspen four months after a wildfire in northern Alberta, Canada, across a fire severity gradient (low, moderate, high), with unburned stands as controls. Wood discs were collected to evaluate the effects of fire severity, stem height, diameter, and bark thickness on MC. Species-specific predictors were used, including stem height and diameter for white spruce and trembling aspen, and bark thickness (BT) and distance from apex (DFA) for lodgepole pine. Stem MC declined significantly with increasing fire severity, with the greatest reductions in white spruce (76
The objective of this study was to investigate the properties of experimental wood pellets manufactured from varying mixture ratios of mahogany (Swietenia macrophylla King), Taiwania (Taiwania cryptomerioides Hayata), and thorny bamboo (Bambusa stenostachya Hackel). The moisture content, mechanical durability, bulk density, calorific value, energy density, ash content, volatile matter content, fixed carbon content, and thermal decomposition behavior of seven types of pellets with different material ratios were determined using thermogravimetric analysis (TGA)/derivative thermogravimetric analysis (DTG) to increase their overall fuel performance from a resource-sustainability perspective. Bamboo-predominant pellets exhibited superior mechanical strength because of their favorable fiber structure but were limited by high ash and volatile contents, resulting in lower energy conversion efficiency. In contrast, the highest calorific value (20.58 MJ/kg), energy density (13.42 GJ/m3), and thermal stability were observed for pellets with relatively high Taiwania contents because of their increased lignin content. The results of Pearson’s correlation analysis revealed significant relationships between raw material proportions and pellet properties. The results of this study suggest that the precise optimization of material ratios can improve pellet fuel quality, reduce the dependence on single species, and support circular bioresource utilization in line with low-carbon energy goals.
Spruce budworm (Choristoneura fumiferana (Clemens)) is the most destructive native forest defoliating insect in North America. Repeated defoliation causes tree mortality over large areas, reducing timber supply and wood quality. Since trees do not all die at the same time, the challenge for the wood transformation industry is to know if dead trees are worth salvaging. The objective of this study was to compare visual lumber grade yield and value extracted from live and dead balsam fir trees in three different states of degradation, based on Hunter classes 2 (live but declining trees), 3 (recently dead trees) and 4 (dead trees with bark peeling off). A total of 92 balsam fir trees were felled on five sites located in the Quebec North Shore region. The trees yielded 354 sawlogs, which were processed into 1044 pieces of lumber. All products were graded visually according to National Lumber Grades Authority (NLGA) standards. Results showed a major loss in wood quality following tree death, with a significant decrease in the volume proportion of high-quality Select Structural and No. 2 lumber grades (No. 2 and Better) from 51
This study investigated the chemical composition of short-rotation Eucalyptus grandis (eucalypt) and Tectona grandis (teak) wood subjected to thermal modification in closed system. Four treatments were evaluated: untreated eucalypt wood (EW), thermally modified eucalypt wood (TMEW), untreated teak wood (TW), and thermally modified teak wood (TMTW). Thermal modification was conducted in closed (pressurized) system using a hygrothermal process at a final temperature of 160 °C. Chemical analyses included the determination of total lignin, hemicelluloses, and extractives (total, cold water, and hot water). Additionally, the solubility of wood was assessed in acetone, chloroform, dichloromethane, and a 1:2 (vol:vol) ethanol-toluene mixture. Thermal modification significantly altered the chemical composition of eucalyptus and teak wood, especially by promoting hemicelluloses degradation (4.9
A novel antibacterial agent was synthesized from Japanese cedar sawdust, a representative woody biomass resource, through chemical modification using potassium permanganate. The oxidation treatment introduced carboxyl groups onto the biomass surface, providing active sites for Ag+ adsorption. X-ray photoelectron spectroscopy (XPS) analysis revealed characteristic Ag 3d peaks at 367.8 and 373.8 eV, confirming the successful adsorption of Ag+ onto the modified biomass. The saturated adsorption capacities of Ag+ were determined to be 48.3 mg g− 1 by the batch method and 73.5 mg g− 1 by the column method. The antibacterial activity of the resulting Ag+-adsorbed material (Cedar-O-Ag) was evaluated against Escherichia coli by observing turbidity, Ag+ release, and colony formation. Cedar-O-Ag induced bacterial cell lysis, with complete bactericidal activity observed at 50 mg, corresponding to an Ag+ concentration of 0.347 mmol L− 1. Colony formation assays confirmed that E. coli growth was entirely inhibited at this concentration. Furthermore, reusability tests demonstrated that Cedar-O-Ag maintained bactericidal activity for up to three consecutive cycles. Overall, these results show that woody biomass can serve as an effective, sustainable, and reusable carrier for antibacterial materials.
Assessing the deterioration of wooden piles embedded in anaerobic environments is challenging, as any changes in the density of the piles proceed very slowly. This study aimed to assess deterioration at an ultra-early stage, such that no significant reduction in density could be observed and the cell wall of the piles exhibited quite minimal deterioration. The deterioration this stage was evaluated by dynamic mechanical analysis (DMA), which is a useful tool for inferring the structure of lignin and the influence of the hemicellulose that interacts with it. Fourier transform infrared (FTIR) analysis and microscopic observations were also performed to support the DMA results. The storage modulus (E') varied with density across the log’s cross section. However, the decrease in E' in the outer region of the log was minimal, which made it difficult to evaluate the extent of deterioration from this parameter alone. In contrast, the peak temperature of loss tangent (tanδ) showed a tendency to be higher in the outermost region of the piles. Because the peak temperature of tanδ typically decreases when lignin is degraded, the result that the outermost region showed higher values than the inner region suggests that the lignin structure in the cell walls was largely preserved. The elevation in peak temperature of tanδ is attributed to the decomposition of hemicellulose, which is consistent with the FTIR results indicating degradation of polysaccharides and the microscopic observations showing localized cell-wall deterioration. These findings demonstrate that DMA provides a sensitive and effective means of detecting deterioration in wood at an ultra-early stage under anaerobic conditions, whereas conventional methods, such as density measurements, may fail to reveal significant changes.
The Brinell ball hardness test is based on either the total surface area of the indentation or the depth of the indentation. Although the Brinell hardness test is well-established, none of its basic definitions have a clear physical justification. Consequently, the Brinell hardness measure in the experiment depends on the load value, with a maximum for half-diameter indentations and a minimum for full indentations. Therefore, a slightly different hardness measure for the ball test has been proposed, which is based on the volume of the indentation and, at the same time, has an energetic justification. The new hardness measure is abbreviated as HVP, derived from the words hardness–volume–pressure, which best reflects the essence of this measure. Two equivalent definitions of the HVP measure have been given. The first geometric definition relates the volume of a real indentation to the indentation volume of an ideal parabolic indenter. The second energetic definition is based on the average volume work of deformation of the material resisting hardness, in terms of pressure (stress). Preliminary experimental results showed no significant correlation between the HVP hardness measure and the applied load. However, the Brinell hardness measure showed a negative correlation with load in two of three sets of transverse section measurements of linden wood. These results reached a statistical significance level of 0.05.
Abstract Priobium carpini (Herbst) is a species of wood-boring beetle. Although it is not commonly found in Japan, occasional cases of extensive infestation in wooden constructions have been reported. In this study, wood pieces containing larvae were subjected to intermittent X-ray computed tomography (CT) scans to observe larval movement and growth, as well as the processes of pupation and adult eclosion. Wood pieces, obtained from infested timbers of Pinus parviflora , were scanned at intervals of approximately 10 days for the observation of larval movement and approximately 5 days for the observation of pupation and adult eclosion. The larval and other stages of the beetle were visualized in the CT images. The larvae mainly moved about within the frass packed inside the wood pieces, without newly tunneling into the intact parts of wood. Based on 12 larvae, the average growth rate of body length during the observation period was estimated to be 0.57 mm/year. In winter, the larvae underwent quiescence when the surrounding temperature was approximately 10 °C or lower. The final instar larvae created pupal chambers beneath the wood surface, and they transformed into prepupae from late April to late May. The prepupal and pupal stages lasted 8 days ( n = 13) and 20 days ( n = 11) on average, respectively. Pupation occurred in May, adult eclosion from late May to late June, and adults exited the wood in June.
Abstract Jiangzhenxiang—the resinous material formed in Dalbergia pinnata — exhibits dense texture, attractive grain patterns, and abundant inclusions, frequently being substituted for or combined with Dalbergia odorifera as the traditional Chinese medicine “Jiangxiang.” Investigating their physicochemical characteristics and clarifying their distinctions will facilitate optimized material utilization. Comparative anatomical analysis through sectioning revealed three key differences: (1) Jiangzhenxiang exhibits more densely distributed vessels, frequently occluded with reddish-brown gum deposits, whereas such deposits are rarely observed in D. odorifera ; (2) its wood rays in Jiangzhenxiang are predominantly uniseriate and non-storied, while D. odorifera possesses predominantly multiseriate rays accompanied by a distinctly storied arrangement of all axial elements; (3) axial parenchyma in Jiangzhenxiang is primarily vasicentric and paratracheal banded (2–5 cells wide), whereas D. odorifera displays aliform, confluent, paratracheal banded, and apotracheal banded configurations. Ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry analysis of wood extracts identified 18 flavonoid compounds and the suggestion of 17 flavonoids in Jiangzhenxiang for the first time, primarily comprising flavonoids, dihydroflavonoids, isoflavones, and chalcones showing compositional congruence with D. odorifera . Both species shared dominant constituents including liquiritigenin, formononetin, calycosin, and isoliquiritigenin. Quantitative variations emerged notably in calycosin and isorhamnetin levels (significantly higher in Jiangzhenxiang, contrasted with fisetin, butin, medicarpin, and dalbergin concentrations [markedly lower than D. odorifera ]). This study delineates microstructural distinctions in vessel pores, wood rays, and axial parenchyma while pioneering the identification of principal flavonoids in Jiangzhenxiang. These findings establish a scientific foundation for its rational application in wood utilization and herbal medicine, particularly regarding its substitutive potential for D. odorifera .
Abstract The aim of this study is to preliminarily clarify the wood properties and lumber qualities of trees of male-sterile Cryptomeria japonica full-sib families, and to evaluate the possible short-rotation forestry using these families, although the number of trees and families used in this study is limited. The standing tree characteristics, wood properties, and dimensional lumber quality (1820 × 38 × 89 mm; visual grading according to the Japanese Agricultural Standards for structural lumber and finger jointed structural lumber for wood frame construction [JAS 0600], and static bending properties) were investigated in 14-year-old trees (12-year-old forest stand) from five male-sterile C. japonica full-sib families developed by the Tokyo Metropolitan Agriculture and Forestry Research Center, Tokyo, Japan. The mean values of stem diameter at 1.2 m above the ground, tree height, and stress-wave velocity of stems in all 22 trees from five families were 15.2 cm, 12.3 m, and 2.45 km/s, respectively. Mean value was also 7.7 mm in annual ring width, 0.31 g/cm 3 in basic density, 26.9° in microfibril angle, 5.60 GPa in modulus of elasticity (MOE), and 58.7 MPa in modulus of rupture (MOR). In lumber quality ( n = 34), annual ring width, bow, crook, twist, slope of grain, air-dry density, MOE, and MOR were 9.4 mm, 0.28%, 0.18%, 1.4°, 0.09%, 0.37 g/cm 3 , 4.79 GPa, and 33.4 MPa, respectively. Although the lumber was obtained from 14-year-old trees, about 90% of lumber pieces exceeded the characteristic value of MOR (28.4 MPa) in the select structural visual grading class of JSII of JAS 600. In addition, the preliminary calculated value of the 95% lower tolerance limit with a confidence level of 75% of the MOR of lumber was 23.1 MPa. Therefore, from the viewpoint of the bending properties of lumber, short-rotation C. japonica forestry producing structural lumber might be established, owing to the improvement of mechanical properties by tree breeding in male-sterile families, although the tested samples were limited.
Abstract Rubber tree ( Hevea brasiliensis ) is a tropical plant, and rubberwood, as a timber, has great utilization potential. In Bangladesh, despite its large potential, limited research has so far been carried out to investigate the properties of rubberwood in terms of seasoning conditions and growing zones. This study investigated selected physical (density, moisture content, volumetric shrinkage) and mechanical (modulus of elasticity ( MOE ), modulus of rupture ( MOR ), compressive strength, shear strength parallel to the grain, and Janka hardness) properties of rubberwood in green and air-dry (AD) conditions, which were harvested after the latex extraction period ended. In addition, differences between samples collected from four geographic locations (Chattogram, Cox’s Bazar, Sylhet, and Tangail) and three different stem heights were considered. Logs from three 32-year-old rubber trees were collected from each of the four sites, totaling 12 sample trees. After felling, the trees were delimbed, and the stems were cut into three logs: bottom (0.5–3.5 m), middle (3.5–6.5m), and top (6.5–9.5m). The logs were then band-sawn into planks with an approximate thickness of 5.08 cm. The planks were further reduced to specimen sizes for each test. After air-drying, all specimens reached an equilibrium moisture content of approximately 12%. Stem height and site conditions had a substantial impact on wood density and mechanical characteristics. Wood collected from the bottom logs and in Tangail had considerably higher ( p < 0.05) densities than those from the upper logs and the other three sites. Within stems, both the green and dry specimens from the bottom logs exhibited 24–32% and 8.6–19% higher mechanical properties, respectively, than those from the upper logs. Air-drying produced noticeable increases in MOE , MOR , compressive strength, hardness, and shear strength. Wood specimens from Chattogram and Sylhet exhibited, on average, better mechanical properties than those from Cox’s Bazar and Tangail. This study offers site-specific data for rubberwood in Bangladesh, emphasizing the combined effects of stem position and site heterogeneity, even though the overall patterns are consistent with accepted wood science concepts. The results highlight the opportunities of rubberwood in the woodworking sector, as this study contributes to the understanding of the variability of rubberwood properties, with useful insights for optimizing raw material selection and utilization of wood sections for specific applications.
Abstract Owing to their high load-bearing capacity and ease of assembly, tensile-bolted joints are widely used in applications ranging from conventional wooden houses to mass timber buildings. However, the current design method contains several critical gaps that may compromise structural integrity, especially for mass timber structures under cyclic loadings: (i) disregarding cyclic effects, (ii) equating compressive yielding with splitting, and (iii) applying the embedment stiffness formula for dowel-type fasteners. Therefore, the aim of this study is to address these gaps through cyclic bending tests. All tests were conducted on column-base connections using glulam members of the same grade. Experimental results showed three failure modes of timber: compressive yielding, bending failure, and splitting failure. In specimens with longer bolt anchorage lengths, the most ductile compressive yielding was observed. The load-bearing capacity determined by compressive yielding could be predicted by the bearing strength of the material. However, regarding the bending failure, the experimental values were smaller than those calculated by the design method. This result could be attributed to both stress concentration around the specimen and the effects of cyclic loading; the latter reduced the modulus of rupture. In the case of splitting failure, although the failure moments for compressive yielding and splitting were similar, the splitting failure was more brittle. Moreover, the specimen that failed in splitting had dimensions identical to that of the specimen that failed in compressive yielding. The rotational stiffness was approximately twice the calculated values for all specimens. This discrepancy can be attributed to the underestimation of embedment stiffness beneath the washers and in the column end grain, as the current calculation is based on dowel-type fasteners. These findings emphasize the need to revise the design method to more accurately account for embedment stiffness in such joints.
Abstract Gas grafting was applied to paper to produce recycled fibers that were partially hydrophobic yet retained hydrophilicity, which were then used in water-resistant molded pulps. To balance water resistance and mechanical strength, dual-layer molds were fabricated with a gas-grafted hydrophobic top layer and untreated hydrophilic bottom layer. The optimal basis weight of the hydrophobic top layer was investigated, as thin layers reduced water resistance while thick layers lowered tensile strength. High-pressure calendering increased layer density but caused excessive pore collapse, diminishing water resistance. Cobb tests showed effective resistance at hydrophobic top layer weights above 80 g/m 2 with ≤ 400 mL of applied water, but penetration accelerated above 600 mL. To explain the nonlinear penetration behavior, an Orthogonal Water Penetration Model was proposed, suggesting that vertical continuity of hydrophilic patches enables breakthrough once the hydrophobic barrier is breached. This model further revealed that fibers with > 50% residual hydrophilic area cannot form a water-resistant layer. Overall, the proposed dual-layer pulp mold design achieves stable water resistance while minimizing hydrophobic fiber usage.
Abstract This study investigated the relationship between cationic polyacrylamide (C-PAM) molecular weight and inorganic filler particle size in paper retention, using the Wet End Process Simulator to replicate industrial sheet forming under vacuum dewatering and vibration. Stocks containing larger-particle talc exhibited greater flocculation and poorer formation than those with smaller-particle ground calcium carbonate (GCC), with formation further deteriorating as C-PAM molecular weight increased from 6 to 8 × 10 6 . The reduced specific surface area of talc limited polymer adsorption, leaving excess C-PAM to promote fiber flocculation. This result demonstrates that the number of polymer electrolytes can be either insufficient or excessive depending on the available adsorption surface area, and that the retention of small-sized fillers with a large specific surface area requires low-molecular-weight C-PAM, which has shorter chain lengths but is present in greater numbers. In mixed-filler systems (talc:GCC = 50:50), higher proportions of 8 × 10 6 C-PAM increased talc retention, while higher proportions of 6 × 10 6 C-PAM enhanced GCC retention. Results indicate that high-molecular weight C-PAM is more effective for large suspended solids, whereas lower-molecular weight C-PAM better retains smaller fillers under limited polymer dosage. These findings provide practical guidelines for selecting retention aid molecular weight based on filler particle size in papermaking.
Wood plays a crucial role in the economies of Central African countries, yet knowledge of the ecological and genetic determinants of intraspecific wood quality variation remains limited. In this study, we combined microsatellite-based population genetic analyses with short-wave near-infrared (NIR) hyperspectral imaging (HSI) of transverse wood slices to investigate the genetic diversity and wood spectral variability of three Entandrophragma cylindricum populations across distinct forest management units in northern Republic of the Congo. Genotyping of adult trees using 10 nuclear microsatellite loci revealed high levels of genetic diversity and low inbreeding across all populations. No significant genetic differentiation was detected among sites, although a weak but significant spatial genetic structure was observed, consistent with an isolation-by-distance (IBD) pattern, suggesting ongoing gene flow over the landscape. Hyperspectral imaging of transverse wood samples highlighted substantial inter-individual and site-related variability in NIR spectral signatures, with the highest spectral heterogeneity observed in the site characterized by the long-term logging history. However, this variability was not correlated with genetic distance, as confirmed by Mantel tests, indicating that site-specific context and logging intensity are the primary drivers of wood spectral variation. The results suggest that E. cylindricum populations retain considerable genetic potential for conservation and improvement. Moreover, the observed site-related variation in wood spectral traits highlights the importance of considering local growing context when interpreting wood spectral variability in tropical timber species. Further research combining near-infrared spectroscopy with detailed wood anatomical analyses and direct measurements of environmental variables would be necessary to disentangle the mechanisms underlying site-associated spectral variation.
Abstract Prehydrolysis/soda–anthraquinone (AQ) cooking has emerged as a promising strategy for the production of high-purity cellulose; however, optimization of the prehydrolysis stage is still required. In this study, monopersulfuric acid (MPS) was evaluated as a prehydrolysis reagent for the production of cellulose from Japanese cedar ( Cryptomeria japonica ) via prehydrolysis/soda–AQ cooking and compared with sulfuric acid (H 2 SO 4 ) under equivalent acid dosages. At high acid dosage, MPS-treated wood showed lower residue yield than H 2 SO 4 -treated wood, whereas H 2 SO 4 treatment resulted in higher Klason lignin content after prehydrolysis. Nitrobenzene oxidation further confirmed lower vanillin yields in H 2 SO 4 -treated wood than in MPS-treated wood, indicating that lignin condensation was suppressed when MPS was used for prehydrolysis. Sugar analysis of the prehydrolysis liquor (PHL) showed that at low H 2 SO 4 dosage (4.8%), MPS and H 2 SO 4 treatments afforded comparable untreated total sugar contents. However, at high dosage (≥ 24%), the untreated total sugar content was lower in MPS-treated PHL, suggesting oxidative transformation or degradation of released carbohydrates. When soda–AQ cooking was conducted after MPS treatment, the resulting pulp showed lower kappa number, improved oxygen-bleaching response, and higher brightness of the final totally chlorine-free (TCF) bleached pulp (83.0% ISO) compared with soda–AQ cooking performed after H 2 SO 4 treatment or without prehydrolysis. However, the brightness differences among the pulps became smaller after the subsequent TCF bleaching sequence, despite the higher brightness of MPS/soda–AQ pulp after oxygen bleaching. Although pulp viscosity did not reach dissolving-pulp grade specifications, the bleached pulp exhibited high glucan purity (≈96%) indicating applicability for high-purity cellulose applications. Overall, the results demonstrate that MPS/soda–AQ is a viable, sulfide-free and chlorine-free route for obtaining cellulose with high glucan content from Japanese cedar. These findings position MPS/soda–AQ cooking as a new biorefinery process for producing high-purity cellulose streams rather than conventional dissolving pulp for advanced material applications from domestic softwood resources in Japan.
The objective of this study was to investigate the full-scale fire performance of Japanese cedar (Cryptomeria japonica D. Don.) timber claddings in accordance with the KS F 8414 standard. Visual inspections revealed that the lower sections of the specimens were carbonized, whereas the upper sections, beyond 2000 mm from the fire source, remained unaffected. Temperature measurements indicated that the highest temperature at the exterior of Level 1 (2500 mm from the upper end of the opening) reached 868.8 °C, while the maximum temperatures at the exterior and interior walls of Level 2 (5000 mm from the upper end of the opening) were 557.8 °C and 249.6 °C, respectively. The highest temperature within the cavity layer of Level 2 was 122.2 °C, complying with safety standards that require temperatures at Level 2 to not exceed 600 °C for more than 30 s over a 15-min period. Additionally, the fire performance of flame-retardant treated cedar was compared with that of flame-retardant-treated commercial phenolic foam. Although both materials passed the fire safety evaluation, the cedar timber claddings exhibited stronger heat-transfer-blocking effects, particularly in the cavity layer of Level 2, where the temperature was significantly lower than that for the phenolic foam. These results underscore the potential of flame-retardant-treated cedar timber claddings as a safe and sustainable building material, providing valuable insights into enhancing fire safety in timber constructions.
