Japanese Cedar Wood Research Articles

Raman characterization of layer of graphene-like structures in 3d-transition metal-loaded charcoal by comparison with X-ray diffraction data

To evaluate the formation and changes in graphitic structures in transition-metal loaded charcoal, charcoal samples synthesized from Japanese cedar wood impregnated with 3d-transition metal (Cr, Mn, Fe, Co, Ni, Cu, Zn) ions were analyzed using microscopic Raman spectroscopy and powder X-ray diffractometry. The metal-loaded charcoal samples were carbonized at 650, 700, 750, 800, and 850 °C in downstream N2 gas. The Raman Gˊ-band, which shows the structural ordering of carbon atoms, was observed in the Raman spectra of Fe-, Co-, and Ni-loaded charcoal. The Gˊ-bands occurred at ≤ 2670 cm− 1 and shifted to 2700–2690 cm− 1 with increasing carbonization temperature. The Gˊ-band observed in the higher wavenumbers (2700–2690 cm− 1) range corresponded to an X-ray diffraction (XRD) peak at ∼ 26.3 ° assigned to the (002) plane of graphite-like structures. The high-wavenumber Gˊ-band also corresponded to the XRD detection of the carbide of the three metals. However, the XRD peak was not found for Co- and Ni-loaded charcoal samples exhibiting Gˊ-bands at ≤ 2670 cm− 1.

Estimation of the earlywood and latewood ratio with different particle size of dry and wet milled Japanese cedar wood flour by using hyperspectral imaging

Mechanical properties of wood–plastic composites are influenced by a particle size and surface morphology of wood flour. Generally various sizes of wood flour are produced from single solid wood even if the single process is used. If the different particle size of wood flour is produced from different wood tissue such as earlywood (EW) and latewood (LW), not only particle size but also density and chemical composition of wood flour might influence the mechanical property of final products. This study aims to investigate the relationship between particle size and their origin; EW and LW. EW and LW were separately milled to produce the EW and LW flour by dry and wet milling. Hyperspectral images ranging 400–1000 nm for each wood flour were used as training data. Discriminant model of EW and LW flour developed by PLS-DA showed over 0.77 of accuracy. Then the EW and LW were dry and wet milled together and screened by three different sieve openings to obtain different particle size wood flour. Discriminant model was applied for the hyperspectral images of each size of wood flour to estimate the EW and LW ratio. The result showed that increasing sieve opening resulted in the increasing ratio of LW for dry milled wood flours. The results suggest that the EW was easily pulverized than LW.

Cesium adsorption ability of charcoal made from Japanese cedar and Japanese oak wood: effect of Fe3+-addition to starting materials

To investigate the effect of Fe-addition on the Cs+-adsorption ability (Cs+-AA) of woody charcoal, charcoal samples were prepared from Japanese cedar (JC) and Japanese oak (JO) wood impregnated with Fe3+ at 600 and 800 °C. The residual functional groups of the charcoal samples were examined using infrared-photoacoustic spectroscopy. OH groups were observed in the charcoal made at 600 °C, and no vibrational bands were detectable in the charcoal synthesized at 800 °C. The observation of Raman D-, G-, and G´-bands revealed that all charcoal samples contained sp2-carbon atoms but graphitization occurred only in the iron-loaded charcoal made at 800 °C. The Cs+-AA of the JC and JO charcoal samples were evaluated based on the adsorption isotherms of an aqueous CsCl (Cs+: 33 mg/L) solution. The addition of Fe3+ to wood had a negative effect on the Cs+-AA of the JO charcoal made at 600 °C, but a positive effect on the Cs+-AA of the JC charcoal prepared at 800 °C.

Physicomechanical properties of Japanese cedar wood modified by high-temperature vapour-phase acetylation (HTVPA), a simultaneous acetylation and heat treatment modification process

Wood modification can be broadly categorized into chemical and physical processes, with acetylation and heat treatment being two of the most common methods in each category, respectively. This study, for the first time, combines these two modification methods and investigates the effects of high-temperature vapour-phase acetylation (HTVPA) on the physicomechanical properties of Japanese cedar (Cryptomeria japonica) wood in the temperature range of 145 to 220 °C for 2 to 16 h. Additionally, the acetylation variations within the wood were evaluated. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and near infrared spectroscopy (NIR) spectral analysis showed that the hydroxyl group of Japanese cedar wood reacted with acetic anhydride to form an acetyl group by HTVPA process. When the HTVPA temperature was 220 °C, dehydration and deacetylation of wood occurred. Furthermore, based on the weight percent gain (WPG) and physicomechanical properties of the treated wood, the 200 °C/8h was considered the optimal HTVPA treatment condition. The profiling analysis results showed that the acetylation depth in the longitudinal direction was 40 mm, while the depth in the tangential and radial directions was 3–4 mm. However, the theoretical WPG of the surface of HTVPA treated Japanese cedar wood was 30.0–31.6 %.

Assessing the Long-Term Creep Behaviour of Hydrothermally Treated Japanese Cedar Wood Using the Short-Term Accelerated Stepped Isostress Method.

In this study, short-term accelerated creep tests were conducted using the stepped isostress method (SSM) to investigate the impact of hydrothermal treatment on the long-term creep behaviour of Japanese cedar wood and to determine optimal hydrothermal treatment conditions. The results showed that SSM can effectively predict the creep behaviour of hydrothermally treated wood. Among the treatment conditions tested, Japanese cedar wood treated hydrothermally at 180 °C for 4 h exhibited higher flexural strength retention (91%) and moisture excluding efficiency (MEE) (44%) and demonstrated superior creep resistance compared to untreated wood. When subjected to a 30% average breaking load (ABL) over 20 years, the specimen's creep compliance, instantaneous creep compliance, b value, activation volume, and improvement in creep resistance (ICR) were 0.17 GPa-1, 0.139 GPa-1, 0.15, 1.619 nm3, and 4%, respectively. The results indicate that subjecting Japanese cedar wood to hydrothermal treatment at 180 °C for 4 h has a negligible effect on its flexural properties but results in significant improvements in both dimensional stability and creep resistance.

Antimultidrug-resistant bacterial activity of microwave solvolysis lignin from woody biomass

Drug-resistant bacteria are a serious concern for human health. Thus, protective substances need to be urgently developed to inhibit the propagation of such bacteria in living environments. We herein report about antibacterial activity of lignin, which was developed via chemical alteration of native lignin in wood. Japanese cedar (Cryptomeria japonica) wood was degraded via microwave solvolysis in an equivolume mixture of 2 % (w/w) aqueous sulfuric acid, ethylene glycol, and toluene at 190 °C for 60 min and fractionated via extraction with toluene, ethyl acetate, and ethanol. The ethyl acetate extract (jEAE) exhibited ≥ 98.5 % inhibitory activity against the drug- and multidrug-resistant strains of Streptococcus pneumoniae. jEAE also exhibited strong inhibitory activity against two nondrug-resistant S. pneumoniae and one Streptococcus pyogenes strains. Lignin-derived monomers having guaiacyl nuclei were detected as major fragments using pyrolysis gas chromatography–mass spectrometry (GC–MS), indicating that jEAE is a solvolysis lignin. In 1H–13C-edited heteronuclear single quantum coherence nuclear magnetic resonance (NMR), signals of guaiacyl nuclei were observed, but those from side chains of β-O-4, β-5, and 5–5/4-O-β substructures disappeared. 31P NMR revealed that jEAE possesses lower and higher amounts of aliphatic and phenolic OH groups, respectively, than milled wood lignin. The high antidrug-resistant bacterial activity of the structure-altered lignin provides a new approach for suppressing the growth of drug-resistant bacteria using lignocellulosic biomass.

Experimental evidence that lignin-modifying enzymes are essential for degrading plant cell wall lignin by Pleurotus ostreatus using CRISPR/Cas9.

Lignin-modifying enzymes (LMEs), which include laccases (Lacs), manganese peroxidases (MnPs), versatile peroxidases (VPs), and lignin peroxidases (LiPs), have been considered key factors in lignin degradation by white-rot fungi because they oxidize lignin model compounds and depolymerize synthetic lignin in vitro. However, it remains unclear whether these enzymes are essential/important in the actual degradation of natural lignin in plant cell walls. To address this long-standing issue, we examined the lignin-degrading abilities of multiple mnp/vp/lac mutants of Pleurotus ostreatus. One vp2/vp3/mnp3/mnp6 quadruple-gene mutant was generated from a monokaryotic wild-type strain PC9 using plasmid-based CRISPR/Cas9. Also, two vp2/vp3/mnp2/mnp3/mnp6, two vp2/vp3/mnp3/mnp6/lac2 quintuple-gene mutants, and two vp2/vp3/mnp2/mnp3/mnp6/lac2 sextuple-gene mutants were generated. The lignin-degrading abilities of the sextuple and vp2/vp3/mnp2/mnp3/mnp6 quintuple-gene mutants on the Beech wood sawdust medium reduced drastically, but not so much for those of the vp2/vp3/mnp3/mnp6/lac2 mutants and the quadruple mutant strain. The sextuple-gene mutants also barely degraded lignin in Japanese Cedar wood sawdust and milled rice straw. Thus, this study presented evidence that the LMEs, especially MnPs and VPs, play a crucial role in the degradation of natural lignin by P. ostreatus for the first time.

Effects of volatile sesquiterpenes from Japanese cedarwood on visual processing in the human brain: an event-related potential study

Odor environments in living spaces can influence human physiological and psychological states. To elucidate the effect of volatile organic compounds (VOCs) of wood in living spaces on the modulations of cognitive processing, we built two experimental huts to simulate wooden construction living spaces. One hut was made of cedarwood (Cryptomeria japonica), and the other was made of resin. We used cedarwood and resin, because they are often used as construction materials in Japan. In both huts, we measured the participants’ first positivity in the early visual cortex (P1), the third positivity elicited by voluntary attention (P3b), and the automatic occipital negativity to infrequent visual stimuli in event-related potentials (ERPs), while they performed a visual discrimination task. The VOCs in both huts were measured by gas chromatography–mass spectrometry. The concentration of volatile sesquiterpenes was significantly increased in the cedarwood hut. Neither P1 nor P3b was affected by the cedarwood hut. Compared to the resin hut, we observed significantly larger occipital negativities to the infrequent stimuli in the cedarwood hut in the time windows of 280–300 ms at the mid-occipital region. These findings suggest that the increased concentration of volatile sesquiterpenes emitted from cedarwood facilitates the human brain’s response to changes in visual stimuli.

Influence of Proteins on the Lignin Decomposition Behavior of Japanese Cedar (Cryptomeria japonica) Wood by Supercritical Methanol Treatment.

The effect of adding protein on the decomposition behavior of lignin in Japanese cedar under supercritical methanol conditions (270 °C/27 MPa) was studied. The Klason method was used to detect the lignin content in the insoluble residue following to a 30 min treatment. Adding either an animal (bovine serum albumin) or plant (soy) protein enhanced delignification from 50 to 65% of the lignin-based wt %. This result was attributed to enhanced lignin depolymerization owing to inhibited lignin recondensation and/or the suppressed formation of polysaccharide-derived char via reactions between the protein and polysaccharides. Although the solubilization of lignin was promoted and the yield of lignin-derived low-molecular-weight compounds increased, the selectivity of major monomers such as coniferyl alcohol (CA) and γ-methylated CA decreased. The addition of proteins has a substantial impact on the decomposition behavior of cell wall components under supercritical methanol conditions. This information provides insights into the use of protein-rich lignocelluloses.

Stable Oligomer Formation from Lignin by Pyrolysis of Softwood in an Aprotic Solvent with a Hydrogen Donor.

Pyrolysis of Japanese cedar wood in diphenoxybenzene (an aprotic solvent) with a hydrogen donor was investigated between 270–380 °C. Under these conditions, re‐condensation via radical and quinone methide intermediates was efficiently suppressed and a thermally stable oligomer was obtained. The oligomer was stable even after the treatment time was extended. Yields of lignin‐derived products at 270 °C were limited to approximately 20 wt %, but increased to >80 wt % (lignin basis) at the higher temperatures. The oligomer yield increased directly with the extent of the cellulose degradation at 350 °C. Based on the NMR analysis results, the ether bonds in lignin were largely cleaved, but condensed linkages such as β‐aryl and β‐β and 5‐5’ types remained. The γ‐hydroxypropyl group was identified as a typical side chain, formed by hydrogenation of the double bond of a coniferyl alcohol‐type structure.

Steam co-gasification of Japanese cedarwood and its commercial biochar for hydrogen-rich gas production

In this study, steam gasification and co-gasification of Japanese cedarwood and its commercial biochar were performed in a lab-scale fixed-bed reactor to investigate the feasibility for producing H2-rich syngas. Ultimate analysis, proximate analysis, Brunauer-Emmett-Teller (BET) surface area analysis, and scanning electron microscopy (SEM) were conducted to understand the changes caused by the carbonization process. The effects of gasification temperature and steam flow rate on gas production yield from the steam gasification of the individual samples were investigated at first, which showed larger gas production yield and less tar yield for the steam gasification of the commercial biochar than that of raw cedarwood, indicating that the commercial biochar obtained from the carbonization process was more beneficial for the gasification. The co-gasification of raw Japanese cedarwood and its commercial biochar with different mixing ratios was conducted at different reaction temperatures. The synergistic effect was obviously observed. Especially, the commercial biochar with the highly porous structure and high content of alkali and alkaline earth metal (AAEM) species might provide the catalytic effect on cracking and reforming of tar derived from the raw cedarwood, resulting in a larger H2 yield. However, the catalytic effect and gasification reactivity of biochar would decrease by increasing the amount of raw-cedarwood in the blends due to the coke deposition on the surface of biochar.

Hydrogen-rich gas production from steam co-gasification of banana peel with agricultural residues and woody biomass

Steam co-gasification of banana peel with other biomass, i.e., Japanese cedar wood, rice husk and their mixture, was carried out for the hydrogen-rich gas production in a fixed-bed reactor. For the co-gasification process, the banana peels were physically mixed with rice husk, Japanese cedarwood and their mixture respectively by different mixing weight ratios. The effects of reaction temperature and the addition amount of banana peel on the gas production yield were investigated by comparing the experimental data with the calculated ones based on the individual biomass gasification at the same condition. It was found that the banana peel with a high content of alkali and alkaline earth metal (AAEM) species exhibited not only high gasification reactivity but also a significant enhancing catalytic effect on the co-gasification process at the low temperature, especially with the biomass containing no silica species. The high content of silica species in the rice husk had a negative effect on the gasification reactivity of banana peel during the co-gasification since it could hinder the release of AAEM from the biomass and/or lead to the possible formation of inactive alkaline silicates. However, the combination of these three samples with the suitable weight ratio could improve the gasification performance at the low temperature due to the synergetic effect provided by high contents of potassium and calcium from banana peel and cedarwood respectively. Moreover, the addition of calcined seashells as the CaO source could further improve the gas production yield, especially the hydrogen gas yield at a relatively low gasification temperature of 750 ℃.

O-06 スギおよびヒノキ材の灰特性に関する産地別の分析結果、およびガス化炉向けの燃料に適した灰溶融特性の測定条件の提案

O-06 スギおよびヒノキ材の灰特性に関する産地別の分析結果、およびガス化炉向けの燃料に適した灰溶融特性の測定条件の提案

Location of uronic acid group in Japanese cedar and Japanese beech wood cell walls as evaluated by the influences of minerals on thermal reactivity

The thermal reactivities of cellulose and hemicellulose are significantly different in cell walls when compared with isolated components and differ in Japanese cedar (softwood) and Japanese beech (hardwood). Uronic acid bound to xylan promotes the thermal degradation of cellulose and hemicellulose, and its effect is different depending on the form of free acid (acting as an acid catalyst) or metal uronate (acting as a base catalyst). We evaluated the location of uronic acid in the cell wall by identifying the components affected by demineralization in pyrolysis of cedar and beech wood. The thermal reactivities of xylan and glucomannan in beech were changed by demineralization, but in cedar, glucomannan and cellulose reactivities were changed. Therefore, the location of uronic acid in the cell wall was established and differed between cedar and beech; close to glucomannan and xylan in beech, but close to glucomannan and cellulose in cedar. Such information is important for understanding the ultrastructure and pyrolysis behavior of softwood and hardwood cell walls.

Effects and interaction of different interior material treatment and personal preference on psychological and physiological responses in living environment

Japanese cedar (Cryptomeria japonica) wood is widely used as a traditional construction material in Japan. The relationship between an individual’s perceived comfort level and a preference for Japanese cedar wood interiors is of interest. We compared volunteers’ physiological responses and subjective evaluations of wooden dwelling spaces with different wood materials: planed Japanese cedar lumber, or printed grain resin sheet overlay boards. Eighty-three subjects were asked to stay in each room for 30 min. We evaluated salivary stress markers, blood pressure, the profile of mood states-brief form (POMS), and a questionnaire that used the semantic differential method to evaluate the subjects’ feeling state for both rooms. The concentrations of the volatile organic compounds in both rooms were also quantified after the experiment. The results demonstrated that the subjects’ evaluation of each room was highly dependent on their preference; each room was evaluated more positively by subjects who preferred it. Although the subjects’ feelings were also influenced by their preference, the room with Japanese cedar did not elicit negative feelings, even from the subjects who disliked it. The subjects’ physiological responses were totally independent of their preferences. Their blood pressure decreased in the Japanese cedar room, and their salivary alpha-amylase activity was repressed in both rooms. These results indicated that the subjective evaluations were influenced in part by the subjects’ preferences, while their physiological responses were not affected. Regardless of which room the subjects preferred, the Japanese cedar room reduced the subjects’ blood pressure compared to the room with artificial materials.

Significant and reversible dimensional changes in hydrothermally compressed cedar wood and its potential as humidity-sensitive actuator

Japanese cedar wood samples were radially compressed by 52% using saturated water vapor at 160 °C. The steam-compressed (SC) samples were boiled in water to recover their compressed shapes, and the shape recovery was evaluated on the basis of the dimensional changes under completely dry condition. The compressed shape of the wood was memorized by steaming for 90 min. After the recovery treatment, the radial and tangential swelling of the wood samples were measured during the moistening and subsequent drying. The SC wood exhibited anomalously large and reversible swelling in the radial direction, whereas its tangential swelling was almost the same as that of the uncompressed wood. The significant and reversible swelling of the SC wood was due to the swimming ring-like expansion and collapse of the folded earlywood cell wall. To evaluate the potential of SC wood as a humidity-sensitive actuator, a wooden bilayer was made by combining SC wood with a cedar wooden veneer. The flexural deformation of the SC wooden bilayer due to humidity change was significantly greater than that of the conventional bilayer, which consists of beech wood and cedar wooden veneer.

Hydrolysis of cellulose and woody biomass over sustainable weak-acid carbon catalysts from alkaline lignin

Low-cost and sustainable weak-acid carbon catalysts were prepared from alkaline lignin (AL) by pyrolysis of AL followed by an acid solution treatment process, and applied for the hydrolysis of cellulose and woody biomass for the production of monomeric sugars such as glucose and xylose, which are important for production of industrial platform chemicals. The effect of pyrolysis temperature on the acidity of the final carbon catalyst was investigated. It is found that the AL-derived carbon catalysts at the pyrolysis temperature of 450 °C (denoted as AL-Py-450) exhibited the highest activity in the hydrolysis of ball-milled cellulose with a cellulose conversion of 70.8% and a glucose yield of 46.3% in a neat water reaction system. Furthermore, with the addition of 0.012 wt% hydrochloric acid (HCl) in the above reaction system, the cellulose conversion was increased to 96.1% with a glucose yield of 69.8%. In the same reaction conditions, the AL-Py-450 carbon catalyst also exhibited good catalytic activity for the hydrolysis of lignocellulosic biomass, i.e., Japanese cedar wood, with yields of glucose and xylose of 47.1% and 40.3%, respectively. Therefore, this study could provide a new perspective to utilize the wasted alkaline lignin as a source for the preparation of sustainable weak-acid carbon catalysts for the hydrolysis of cellulose and lignocellulosic biomass.

Effect of Vapor-Phase Surface Acetylation of Japanese Cedar Wood on Fungal Degradation and Dimensional Stability

Vapor-phase acetylation of heartwood in Japanese cedar wood (Cryptomeria japonica D. Don) was carried out as a surface acetylation method to elucidate the relationship between the depth of acetylated area and fungal decay resistance. The acetylated wood (VPAW), prepared with acetic anhydride vapor by heating at 80°C for 72 h, indicated a significant fungal decay resistance and dimensional stability in water-soaking test, similar to liquid-phase acetylated wood (LPAW). The VPAW provided more than 15% of the weight percent gain (WPG) up to a depth of 7 mm from the wood surface, while LPAW gave ∼20% WPG uniformly throughout the wood. However, 24-h vapor-phase acetylation, giving 15% WPG at a depth of 0–2 mm, showed insufficient fungal decay resistance. These results showed that at least 7 mm thickness of the acetylated region with 15% WPG was required to suppress the fungal decay of acetylated wood under laboratory conditions.

Acoustic spatial radiation characteristics of a violin made of Japanese cedar wood produced in Nara Prefecture

Acoustic spatial radiation characteristics of a violin made of Japanese cedar wood produced in Nara Prefecture

Thermal Conductivity of Low-Density Wood Composite Mats

Abstract In order to effectively use the waste produced during lumber sawing, the thermal conductivities of wood composite mats shaped by thermoforming and composed of wood shavings, kenaf fibers, and binders were examined by assuming a one-dimensional heat transfer process that could be described by the sum of its heat conduction and radiation components. To improve the heat-insulating properties of the mats, various types of auxiliary raw materials were examined. Mat density depended on the volumetric ratio of the air layer inside the mat to the fiber layer. In the low-density region, increasing the mat density decreased the magnitude of the radiation component and thus the thermal conductivity of the mat, whereas in the high-density region, increasing the mat density increased the value of the conduction component, which in turn enhanced the thermal conductivity of the mat. The minimum value of the thermal conductivity obtained under all experimental conditions is 0.062 W/m·K. Thus, it is difficult to decrease the thermal conductivity of the mat below 0.060 W/m·K by varying its density and mixing ratio. The utilized model predicted that mat thermal conductivity would be less than 0.060 W/m·K if the fibers with a density similar to that of Japanese cedar wood (0.40 g/cm3) were used.