• Title/Summary/Keyword: Paulownia wood

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Nondestructive Evaluation of Strength Performance for Heat-Treated Wood Using Impact Hammer & Transducer

  • Won, Kyung-Rok;Chong, Song-Ho;Hong, Nam-Euy;Kang, Sang-Uk;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • v.41 no.5
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    • pp.466-473
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    • 2013
  • Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for heat-treated wood under different conditions. The effect of heat treatment on the bending strength and NDE technique using the resonance frequency by impact hammer and force transducer mode for Korean paulownia, Pinus densiflora, Lidiodendron tulipifera and Betula costata were measured. The heat treatment temperature has been investigated at $175^{\circ}C$ and $200^{\circ}C$, respectively. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. In all conditions, It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by impact hammer mode is more useful as a nondestructive evaluation method for predicting the MOR of heat-treated wood under different temperature and species conditions.

Analysis on Antifungal Activity of Paulownia-Wood Storage Box and Application of Natural Biocide for the Activity Enhancement (오동나무상자의 항균활성 분석 및 활성 증진을 위한 천연 살생물제 적용연구)

  • Chung, Yong-Jae;Kang, So-Yeong;Choi, Yun-A
    • Journal of Conservation Science
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    • v.24
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    • pp.75-83
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    • 2008
  • In order to assess antifungal activity of a wooden storage box, which was made of Paulownia tomentosa and used for keeping ancient documents, antifungal activity of volatile organic compounds emitted from the box was investigated along with qualitative analysis on major substances of the compounds. After collecting floating microorganisms inside air tester, the fungal activity was assessed by counting the number of colonies growing on TSA media. Compared to the control which collected 85 colonies from outdoor, 72 colonies were observed showing reduction rate of 14.82%. Through GC/MS and TDS system analysis, limonene was detected from the volatile organic compounds as characteristic features. When the fungal activity was assessed through fumigation by adding natural biocide BI and BII containing eugenol and anethole as major substances, both biocides showed a strong fungal activity with respectively 92.6%(inside the box) and 99.9%(outdoor) of reduction rate. Although these results didn't clarify antifungal activity of the volatile organic compounds emitted from the Paulownia-wood storage box and their functional components, it was at least confirmed that there is application possibility of natural biocide to use for preservation of ancient documents with increased efficiency in controlling pests of wooden storage boxes.

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Estimation of Heat Sterilization Time of Chinese Laminae Species Used in The Production of Glue-laminated Board (집성재 제조용 중국산 층재 수종의 적정 열처리 시간 평가)

  • Kim, Min-Ji;Shin, Hyun-Kyeong;Kim, Gyu-Hyeok
    • Journal of the Korean Wood Science and Technology
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    • v.44 no.5
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    • pp.760-766
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    • 2016
  • This study explored the effects of heating temperature and laminae thicknesses on the time required to heat the center of air-dried Paulownia tomentosa, Pinus sp., Abies sp., and Larix sp. laminae to $56^{\circ}C$, which is a minimum core temperature of wood packaging materials defined by ISPM 15 standard, and maintain for 30 minutes in dry heat treatment schedule. Heating times were different among wood species and were Pinus sp. ${\geq}$ Abies sp. > Paulownia tomentosa > Larix sp. in decreasing order. The differences in heating times of some species were significantly different statistically, but were not different enough in practical terms to warrant heating four species separately. Heating times decreased as heating temperature increased and followed approximately power-function relationship. Also, heating times increased linearly with increasing laminae thickness. These relationships make it possible to calculate intermediate heating times relative to experimentally observed heating times. The results of this study will serve as a guideline for heat sterilization of Chinese laminae species to meet heat treatment requirements for protection against invasive pests.

Analysis of Heat Transfer Characteristics by Materials in Closed Conditions Using Acrylic Hemisphere (I): Comparison of Interior Finishing Materials (아크릴 반구를 이용한 밀폐 조건에 따른 재료별 열 이동 특성 분석(I): 실내마감재 종류에 따른 비교)

  • YANG, Seung Min;LEE, Hyun Jae;KANG, Seog Goo
    • Journal of the Korean Wood Science and Technology
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    • v.48 no.2
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    • pp.217-230
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    • 2020
  • Global warming has increased interest in reducing greenhouse gas emissions. And a policy has effort to reduce energy consumption as a greenhouse gas reduction plan. In Korea, 25% of total energy is consumed in the building sector. In order to reduce energy consumption of buildings, it is possible to expand the utilization of wood as a structural material or thermal insulation materials with low thermal conductivity. It is also reported that when used as an interior finishing material, the energy consumption of the building is reduced by up to 7% by insulation performance. In this study, the heat transfer characteristics and the heat capacity were compared according to the three type of finishing materials(cement, paulownia coreana, medium density fiberboard) normally used as indoor finish materials. Through this study, most of the heat transfer volumes are transferred in the form of radiant heat, and the result was derived from the highest amount of energy and heat transfer in the use of paulownia coreana. When indoor finishing materials are used as wood, it is deemed that energy efficiency inside the building will be improved.

Study of Surface Roughness by Cutting Angle at Turning of Non-iron Metal (비철금속의 선삭시 윗면 절삭각이 표면 거칠기에 미치는 영향에 관한 연구)

  • Jun, Jae-Uhk;Chung, Jin-Seo;Shin, Kou-Dong;Koo, Yang;Ha, Man-Kyung
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.236-241
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    • 2000
  • In the present industry, there is not only the cutting of iron metal, but also the cutting of alloy aluminum, brass and plastic to wood(Paulownia). A variety of material is used and these industry is made need of the cutting material but lots of experiments processing is not enough at the moment. At this point, our team processed the basic experiment about influencing of cutting angle of bite concerned to manufacture in the turning of non-iron metal. Generally speaking, we recognized that there was occurrence of increase of rough surface with increasing of cutting angle in the non-iron metal. but in the cutting of wood we knew, there was special change with change of cutting angle.

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Studies on the Evaluation of Acoustical Properties of the Replaceable Species for Sounding Board by Vibration Test (진동시험(振動試驗)에 의한 대체향판수종(代替響板樹種)의 음향적(音響的) 성질(性質)의 평가(評價)에 관한 연구(硏究))

  • Kang, Chun-Won;Jung, Hee-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.1
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    • pp.71-80
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    • 1991
  • This study was carried out to investigate replaceable species with the conventional sounding board sitka spruce. by comparing the dynamic properties such as density, dynamic Young's modulus and internal friction Dynamic Young's modulus. internal friction of longitudinal and radial direction measured in free mass-free boundary condition for facile vibration analysis and measured by forced vibration method. Dynamical properties of four species were measured on squared plate specimen that the four edges were hung vertically by threads and driven magnetically through an iron piece glued on the specimen, by the use of condenser microphone as vibration transducer, and analyzed by FFT analyzer. The results obtained were as follows: 1. Chaldni method using aluminum powder was proper to identify the vibration mode in the plate vibration and it was possible to verify the resornance mode. 2. It was considered that it was necessary to investigate the influence of adhesive part on the plate vibration when the sounding board was made by two or three small board adhesion. 3. It was considered that plate vibration method, which was a superior to the vibration test of beam, was suitable for selecting suounding board because dynamic Young's modulus and internal friction show different order according to longitudinal and radial direction. 4. Paulownia tomentosa Thunb.) Steudel has been considered to be replaceable species with sitka spruce because it has high dynamic Young's modulus compared with low density, low internal friction, and K value of Paulownia tomentosa (Thunb.) Steudel is greater than that of sitka spruce.

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Acoustic Property and Hardness of Coatings for Musical Instruments with Various Coating Thicknesses

  • Hwang, Hyeon-Deuk;Lee, Byoung-Hoo;Choi, Jae-Hoon;Kim, Hyun-Joong;Chung, Woo-Yang
    • Journal of the Korean Wood Science and Technology
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    • v.34 no.2
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    • pp.58-67
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    • 2006
  • The relationship between acoustic property and coating hardness of musical instruments was investigated using a sound level meter and a pendulum hardness tester. Urethane topcoat, oil stain, natural oil varnish, and UV-curable epoxy acrylate coatings were applied on four different substrates: Paulownia coreana, Pinus koraiensis, Castanea crenata var. dulcis and Pinus densiflora. The influence of the coating type on the acoustic properties was stronger than that of the substrate. In the case of an oil stain formed with tacky coating layer, the sound pressure level (SPL) and surface hardness decreased with increasing of coating thickness. In the other coatings, SPL decreased and hardness increased as the coating layer thickened. However, SPL began to increase again at coating thickness above $100{\mu}m$.

A Study on the Material of Furniture in Goryeo (고려시대 가구재료 연구)

  • Cho, Sook-Kyung
    • Journal of the Korea Furniture Society
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    • v.25 no.1
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    • pp.19-27
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    • 2014
  • This paper studied the materials of the furniture which the noble men used in Goryeo, based on the furniture material category of solid wood furniture, lacquerware inlaid with mother-of-pearl and hardware. As for the solid wood furniture, the wood and furniture types are inferred based on the documents. The trees used for the wood furniture were zelkova, korean willow, pine, royal paulownia, maidenhair tree, korean pine, chinese juniper and elm. The furniture types were table, chair, wooden bench, small portable table, writing table, and folding screen. As to the types of lacquerware inlaid with mother-of-pearl, most of them were hams with top, which were made of abalone shells. The features of the lacquerware inlaid with mother-of-pearl were in detail and elaborate like the pattern of the full bloomed chrysanthemum. Writing tables were also made of lacquerware as pieces of furniture. Distinctively, the mother-of-pearl furniture material was popular enough to be used even in a horse saddle. Regarding the metal feldspar used as both a practical use and decoration, there are drop handle, hinge, the front basis, and lock seen in the artifacts, which were made of cast iron, bronze, and brass. Their manufacture techniques were eojamoon, bratticing and sheet metal. Through this study of the furniture materials used in Goryeo, it seems that Goryeo furniture focused on the functions rather than on the decorations, and in turn the forms were simple and basic. The technique of mother-of-pearl, a bit elaborate one, was used in the props furniture like kitchen wares, hams, or writing talbes. Probably, the solid wood is inferred to be used in a low wooden bench, a chair, and a table based on the documents.

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Major Species and Anatomical Characteristics of the Wood Used for National Use Specified in Yeonggeon-Uigwes of the Late Joseon Dynasty Period (영건의궤 기록을 활용한 조선후기 국용목재의 주요 수종 조사 및 해부학적 특징)

  • LEE, Hyun Mi;BAE, Jae Soo
    • Journal of the Korean Wood Science and Technology
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    • v.49 no.5
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    • pp.462-470
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    • 2021
  • To find out the wood species used in national wood structures in the late Joseon Dynasty, 11 volumes of Yeonggeon-Uigwes were reviewed. It was confirmed that the wood was mainly used for the repair and restoration of palaces, shrines, and fortresses. In the 17th to 20th centuries, the wood species specified in Yeonggeon-Uigwes have revealed either hardwood or softwood. As hardwood species, Juglans mandshurica, Zelkova serrata, Fraxinus rhynchophylla, Betula schmidtii, Paulownia coreana, or Quercus spp. (Quercus aliena; Q, variabilis; Q, dentata; Q, acutissima; Q, mongolica; Q, serrata) were used. As softwood species, Pinus densiflora and Pinus koraiensis were used. Investigation of the wood species is important part because the same species is required as a principle when reparing cultural heritage. In this study, the anatomical images of the wood species were investigated for some samples which were taken from the same species that has been stored in the wood specimen room of the National Institute of Forest Science, instead of the actual wood material used. It was possible to find out the wood species of each member in the wooden cultural heritage buildings by reviewing the Yeonggeon-Uigwes in the late Joseon Dynasty, and the anatomical images of the wood species required for determining the wood species in the repair or restoration of the buildings.

Effect of Heat Treatment and Particle Size on the Crystalline Properties of Wood Cellulose (입자크기 및 열처리가 목재 셀룰로오스의 결정 특성에 미치는 영향)

  • Kim, Ah-ran;Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.47 no.3
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    • pp.299-310
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    • 2019
  • This study was carried out to investigate the effect of heat-treatment and particle size on the crystalline properties of the wood cellulose. The color of wood flours was changed from light yellow in control sample to dark yellow or deep brown by heat treatment at $100^{\circ}C$ to $200^{\circ}C$. Relative crystallinity of the heat treated wood cellulose decreased with decreasing particle size from wood chips to 200 mesh, and there was little change in the crystal width. As the temperature was increased, relative crystallinity of the wood increased and crystal width was not changed. As a result of the FT-IR analysis, it was confirmed that the peaks were gradually decreased at -OH elongation as the heat-treated temperature was increased. The lignin C-H bending of $1425cm^{-1}$ and the hemicellulose C-H bending of $1370cm^{-1}$ did not change with the increase of the heat treatment temperature. In addition, it was revealed that C-C stretching of carbohydrate near $1031cm^{-1}$ decreased with increasing heat treatment temperature. Consequently, it is suggested that particle size and heat treatment affected the crystalline properties of wood cellulose.