• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.8-20
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• 2019

This study was conducted to analyze the pore structure of Yellow poplar. Cross-sectional surfaces of heartwood and sapwood of Yellow poplar (Liriodendron tulipifera) were observed by SEM, and the true density of the heartwood, intermediate wood and sapwood were measured by gas pycnometery, while gas permeability and pore size of heartwood, intermediate wood and sapwood were measured by capillary flow porometery. The pores were classified as through pore, blind pore and closed pore. It was determined that the permeability was increased due to the content and size of through pore being increased although the total porosity of specimen showed slight difference from pith to bark. The content of through pore porosity was 33.754 % of heartwood and 47.810 % of sapwood, showed an increasing trend from pith to bark, however, those for the blind pore porosity and closed pore porosity were 27.890 % and 19.492 % for heartwood and 19.447 % and 4.660 % for sapwood, showed a decreasing trend from pith to bark. The max pore size of specimens was increased by about 5 times from $5.927{\mu}m$ to $31.334{\mu}m$, and mean flow pore size was increased by about 315 times from $0.397{\mu}m$ to $12.437{\mu}m$ from pith to bark.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.358-373
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• 2013

In this study, both mild acid and alkali treatments with 1.0 wt% and 2.0 wt% of $H_2SO_4$ and NaOH solution were applied to evaluate the effects on chemical compositions of wood biomass. Yellow poplar (Liriodendron tulipifera L.) and larch (Larix kaempferi C.) were chosen due to major species planted in Korea. Chemical treatments of biomass were carried out by being soaked in either acid or alkali solution with 1:20 ratio for 72 hours at ambient temperature. Afterward, lignin, 5 major reduced sugars, ash contents and elemental composition were determined. To statistically understand the relationship between samples and chemical treatments, the Tukey test, simple linear regression model and ANOVA analysis were introduced using a statistical software R. As results from both wet chemistry and statistical analysis, yellow poplar was more affected on the lignin and xylose contents by acid treatments under these experimental conditions. Meanwhile, larch was more affected on the composition of galactose and lignin by alkali treatments. A series of results in this study would show that equivalent chemical treatment makes a change the chemical composition of each species.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.166-171
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• 2016

Size reduction is one of the major pre-processing operations in using biomass as a source of energy or raw materials for forest products industry. The grinding characteristics of dried yellow poplar wood chips were investigated using laboratory knife mill with three different screen aperture diameters to provide the basic information for the optimizing of size reduction processes in biomass industry. Average specific energy consumptions were 0.157, 0.137, and 0.093 Wh/g for the screen aperture diameters of 5.0, 7.5, and 9.0 mm, respectively. According to the results of size distribution analysis of ground particles, the sizes of the most of ground particles were much smaller than the aperture diameters of the screens installed on knife mill used in this study.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.35-40
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• 2010

Variations in hexeneuronic acid content in hardwood alkaline pulps were investigated to evaluate their contribution to kappa number. Out of diverse chemical pulps the highest hexeneuronic acid content were measured in yellow poplar kraft pulping, which was assumed to enhance ca. 7.0 of kappa number determined by acid permanganate consumption. In yellow poplar soda-anthraquinone pulping, hexeneuornic acid was contributed to increment of 5.0-6.0 kappa number. In eucalyptus alkaline pulping, hexeneuronic acid content was not significantly different from soda-anthraquinone pulping. Increment of Kappa number by hexeneuronic acid was 4.5-5.6 depending on pulping method and pulping time at target temperature.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.86-94
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• 2011

Pyrolytic lignin was obtained from biooil produced with yellow poplar wood. Fast pyrolysis was performed under various temperature ranges and residence times using fluidized bed type reactor. Several analytical methods were adopted to characterize the structure of pyrolytic lignin as well as the effect of pyrolysis temperature and residence time on the modification of the lignin. The yield of pyrolytic lignin increased as increasing pyrolysis temperature and decreasing residence time of pyrolysis products. The molecular weight of pyrolytic lignin determined by gel permeation chromatography (GPC) was approximately 1,200 mol/g, which was approximately a tenth of milled wood lignin (MWL) purified from the same woody biomass. Based on analytical data, demethoxylation and side chain cleavage reaction were dominantly occurred during fast pyrolysis.

• Journal of the Korean Wood Science and Technology
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• v.33 no.5 s.133
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• pp.66-75
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• 2005

Soybean-based adhesives have recently been reconsidered as alternatives to petroleum-based adhesives due to the uncertainty of availability of petrochemical products and the increased demand for wood adhesives. This study was conducted to investigate the adhesive properties of alkaline phenolic soy (APS) resin for hybrid poplar flakeboard. The APS resin was formulated by crosslinking an alkaline soy flour hydrolyzate with lab-prepared PF resin in the soy hydrolyzate to PF resin weight ratios of 70/30, 60/40, and 50/50. The APS resins were used to fabricate homogeneous hybrid poplar flakeboards with different resin solid levels (5%, 7%, and 9%), press temperatures (175 and $200^{\circ}C$), and press times of 8 and 10 minutes. The IB, wet MOR, and dimensional stability properties of board improved with increasing press time, press temperature, and PF level in APS resins. Increasing press time can be used to offset poor IB strength associated with a 9% resin solid level and the excessive moisture content in the mat. The following conditions were concluded to meet the requirements of the CSA standard for exterior-grade flakeboard: a 50% PF level, a 5% resin content, a $200^{\circ}C$ press temperature, and an 8 minute press time.

• Journal of Forest and Environmental Science
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• v.38 no.4
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• pp.249-255
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• 2022

The study was conducted to establish a method for the proliferation of hybrid poplar (P. alba × P. glandulosa) clone Bongwha1, an excellent biomass species. It was found that to collect the cuttings of Bonghwa1, it was necessary to use the main stem rather than the axillary branch. Stem growth by green-wood cuttings showed a tendency to decrease as the length of the collected cuttings increased, but the survival rate was low. Therefore, modified leafy stem cutting was attempted to increase the survival rate of the cuttings. In the modified leafy stem cutting method, 4 leaves were included in the cuttings, and especially, cuttings were performed using cuttings containing 2-4 cm xylem parts. Leafy stem cutting increased root growth and the number of stems, as well as the survival rate of hybrid poplar clone Bongwha1 compared to green-wood cuttings. The root growth of the leafy stem cutting poplar was better as there was more xylem part. Using two-year-old nursery stocks, the leafy stem cutting was used to produce about 66 cuttings. This study is expected to contribute to the mass propagation of high-quality nursery stocks.

• Journal of Forest and Environmental Science
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• v.26 no.2
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• pp.131-136
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• 2010

In an effort to evaluate the qualities of the unused woods designed for art materials, Yellow pine, Pitch pine, Suwon poplar, Platanus and Cherry grown in Korea has been investigated in the study. Physical and mechanical properties such as density, hardness, roughness, and abrasion of the woods were examined. Among the five species, Cherry wood showed the highest density in green, air-dried and oven-dried conditions. Hardness of Cherry wood was higher than those of Suwon poplar and Platanus. In softwoods, Pitch pine showed greater hardness than Yellow pine. Yellow pine and Platanus had the highest values of wood surface roughness. Abrasion value of cross, radial and tangential sections was the highest in Yellow pine and Suwon poplar. It has been concluded from the experiment that physical and mechanical properties such as density, hardness, roughness, and abrasion of the woods can be used as an indicator of the suitability for woodcraft material.

• Journal of the Korean Wood Science and Technology
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• v.50 no.3
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• pp.167-178
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• 2022

To investigate the influence of manufacturing environment on bonding performance of mixed cross laminated wood (CLT) using polyurethane (PUR) adhesive, a boiling water soak delamination test according to the temperature and relative humidity was conducted. The 5-ply mixed CLT consisted of Japanese Larch for external and middle layer and yellow poplar for internal layer. The PUR adhesives with different opening times of 10 and 30 minutes were used. The mixed CLT was manufactured according to pressing times of PUR and manufacturing environments of summer and winter. In case of summer environment, the delamination rate of the mixed CLT with pressing time of 4 hours using a PUR adhesive with open time of 10 minutes met the requirements of KS F 2081. In case of winter environment, the delamination rate of the mixed CLT didn't meet the requirements of KS standard. However, it was possible to confirm the effect of improving the adhesive performance by adjusting the pressing time according to the open time of the adhesive under the manufacturing conditions. The delamination rate of CLT with open time 30 minutes PUR, manufactured by indirect moisture supply methods was 11.2% better than direct moisture supply methods. As a result of delamination test in the same condition of relative humidity and adhesive, it was found that the temperature of manufacturing environment influences the adhesive performance.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.725-732
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• 2014

Phytoremediation is a technology to mitigate the pollutant concentrations such as metals, pesticides, solvents, oils, or others in contaminated water and soils with plants. The plants absorb contaminants through the root and store them in the root, stems, or leaves. Rapid growth trees such as poplar are used to remove low concentrated contaminants eco-friendly and economically in a wide contaminated region. This study was practiced to evaluate an activated carbon production system by using poplar wood discarded after phytoremediation. Life cycle assessment methodology was used to analyze environmental impacts of the system, and the functional unit was one ton of harvested poplar. It was estimated that the small size rotary kiln for activated carbon production from poplar wood had an environmental benefit in optimized conditions to minimize energy consumptions. The results of an avoided environmental impact analysis show that the system contribute to reduce environmental impacts in comparison with activated carbon production from coconut shell.