• Title/Summary/Keyword: Red Pine

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Microwave-Vacuum Drying of Short Roundwoods and Wood Turneries (단척 통나무와 선반가공목의 마이크로웨이브-진공 건조)

  • Kang, Ho-Yang
    • Journal of the Korean Wood Science and Technology
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    • v.29 no.4
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    • pp.25-32
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    • 2001
  • A microwave vacuum (MW/V) dryer was developed for drying short roundwoods, from which woodcraft souvenirs in Korean market are mostly made, and which were hardly dried without defects in a conventional kiln. It consisted of three 1.5 kW magnetrons of 2,450 MHz, a vacuum pump, a load cell of 100 kg and a cavity of $580{\times}580{\times}1,360\;mm^3$. A computer program was developed to switch on or off the magnetrons according to drying schedules, those were based on microwave injection time or the average of wood temperatures. To evaluate the new MW/V dryer the roundwood specimens of rigida pine, poplar and birch were dried. Their log diameters and lengths ranged from 125 to 25 em and from 25 to 50 cm, respectively. In spite of the presence of minor drying defects, the MW/V drying is found to be an effective method for drying short roundwoods. Wooden turneries made of red alder and ash logs were also MW/V dried from green to 4%MC without any degradation. The rates of the MW/V drying were examined for three different lengths of poplar logs.

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Analysis of Fire Characteristics based on the Thickness and Incident Heat Flux of Wood (합판류 목재의 두께별 입사열유속에 따른 연소특성 비교 연구)

  • Hwang, Sun-Woo;Park, Won-Hee;Kim, Chang-Yong
    • Fire Science and Engineering
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    • v.34 no.4
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    • pp.13-21
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    • 2020
  • This study tested the wood used in building interiors; each type had various incident heat fluxes based on their thickness. The combustion characteristics measured were effective heat of combustion, heat release rate peak and arrival time, maximum average rate of heat emission, and piloted ignition temperature. The wood specimens used in the experiment were 4.8 to 18 mm thick. 25, 35, 50, and 60 kW/㎡ were applied to the incident heat flux that the wood specimens were exposed to. The wood specimens tested were two types of medium-density fiberboard (each with a different density), treated red pine, particle board, and plywood. A comprehensive comparison of different fire characteristics was conducted to analyze the fire patterns corresponding to each type of wood in this way, the risk of fire was studied. The risk of fire was particularly high for particle board. The results of quantifying the fire characteristics of the types of wood studied could function as important input data with which to calculate the fire load of composite combustibles.

A Study of Housewives' Attitudes on the Festive Days and Dishes in Korea -In the Region of Seoul and Choongchung Province- (우리나라의 명절과 음식에 관한 주부들의 인지도 연구 -서울과 충청지역을 중심으로 -)

  • 조후종;조진아;최성은
    • Journal of the East Asian Society of Dietary Life
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    • v.8 no.3
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    • pp.235-245
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    • 1998
  • The purpose of this research was to determine the dishes most commonly served during various festive days. This research studied the habits of housewives in Seoul and In the Choongchung province who have children in high school. 1. Most of the housewives in Seoul graduated from high school. On the other hand. those in the Choongchung province graduated from elementary school in their education backgrounds. The monthly income ranged from 1,550,000 won to 1,190,000won to 1,190,000 won for the housewives of Seoul, and from 1,000,000 won to 1,490,000 for those of Choongchung. The nuclear family system was dominated in both areas and 63.8% of the housewives had a full-time job. 2. "Sulnal(The New Year's Day), Chusuk(Thanksgiving Day), Jungwol-daeborum(The 1st Full-Moon Day)" are among the festive days celebrated in 85% of the both areas, and "Yuwol-Yudu(6th, June), Chungyangjul(9th, September), Naphyang(8th, September)" were celebrated in 0.5%. 3. Traditional festive dishes with respect to the festive days were as follows. Tuckuk(rice cake soup) was a favorite food in Sulnal(The New Year's Day), Burum(Peanut,pine-nut, walnut, etc) in Jungwol-daeborum(The 1st Full-Moon Day), Samgyetang(chicken soup) in Dongji Songpyen(rice cake) in Chusuk(Thanksgiving day) and Patjuk(small red beans soup) in Dongji (22th, December). No significance was found in the number of dishes. 4. The Regional differences the festive days such as Sulnal(The New Year's Day), Ipchun(4th, February), Jungwol-daeborum(The 1st Full-Moon Day), Samwol-samjit(3th, March) Sawolchopail(Budda's birthday), Tano(5th, May), Yuwol-yudu(6th, March) Sawolchopail Budda's birthday), Tano(5th, May), Yuwol-yudu(6th, June), Chilwol-chilsok(7th, July), Suddal -gumum (The year's last day) were very significant 5. The festive days should continue. On the other hand, the menu(dishes) of the festive days should be simplified.hould be simplified.

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The Evaluation of Correlation between Disturbance Intensity and Stand Development by Natural Forest Community Type Classification (자연림 군집형 분류에 의한 교란의 정도와 임분 발달 사이의 관련성 검토)

  • Kim, Ji Hong;Hwang, Kwang Mo;Kim, Se Mi
    • Journal of Forest and Environmental Science
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    • v.29 no.3
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    • pp.219-225
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    • 2013
  • The correlation between disturbance intensity and stand development was evaluated on the basis of natural forest community type classification in areas of Baekhaksan (more disturbed area) and Hwangaksan (less disturbed area). The vegetation data were collected by point-centered quarter sampling method, and they were subjected to cluster analysis for classifying community types and to analysis of species composition and species diversity for reviewing ecological characteristics. By the method of cluster analysis, natural forests of Baekhaksan were classified into Quercus forest community, Pinus densiflora community, Q. variabilis community, and Q. mongolica community. Those of Hwangaksan were divided into P. densiflora community, Q. mongolica community, Q. forest community, and Mixed mesophytic community. It is presumed that more developed and less disturbed forest area shows multiple species community pattern and more diversified structure than less developed and more disturbed forest area. In Korean peninsula, the abundance of red pine may play an important indicator to estimate the developmental pattern of the forest after artificial disturbance. The overall evaluation indicated that less disturbed Hwangaksan area had more developed stand pattern with mixed mesophytic community, more complicated species composition, and higher species diversity than Baekhaksan area.

Effects of fire on Vegetation and Soil nutrients in Mt. palgong (팔공산에서 식생과 토양에 미치는 산불의 영향)

  • Sim, Hak-Bo;Kim, Woen
    • The Korean Journal of Ecology
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    • v.21 no.5_1
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    • pp.465-473
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    • 1998
  • This study was carried out to investigate the developmental process of plant community during the secondary succession and changes of soil properties in the burned areas lapsed 28 years after the forest fire in Mt.Palgong. The forest fire occurred on March, 1969 and the red pine (pinus densiflora) forest and its floor vegetation were burned down. The results are summarized as follows: the floristic composition of burned and unburned areas were composed of 49 and 48 species of vascular plants, respectively. The dominant species based on SDR4 of the burned sites were Lespedeza maximowicxii(87.75), Carex humilis (62.94), Rhododendron schippenbachii(55.78) and Miscanthus sinensis var.purpurascens (51.94). In contrast, Pinus densiflora (81.17), Quercus serrata (53.58)m Carex humilis (53.11) and Miscanthus sinenis var. purpuracens (52.42) were dominant in the unburned area. The biological spectra showed the $H-D_1-R_5-e$ type in both areas. The indices of similarity (CCs) between the two areas were 0.80. Degree of succession (DS) was 734 in the burned area and 809 in the unburned area. The species diversity (H) and evenness indices (e) in the burned and unburned areas were 2.05, 2.13 and 0.53, 0.55, respectively. Dominance index (C) in the burned and unburned areas were 0.30 and 0.32, respectively. Soil properties such as soil pH, content of organic matter, total nitrogen, total carbon, exchangeable potassium, sodium, calcium, and magnesium in burned area were comparatively higher than those of unburned area. Monthly changes of soil properties were of little significance except for some cases. These results suggest that there was relationship between trend of vegetation recovery and the changes of soil properties after the forest fire. Mixed forestation of fire-resistant species and nitrogen fixation species will be effective for reforestation after the forest fire.

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Tree Ring Ca/Al as an Indicator of Historical Soil Acidification of Pinus Densiflora Forest in Southern Korea

  • Lee, Kwang-Seung;Hung, Dinh Viet;Kwak, Jin-Hyeob;Lim, Sang-Sun;Lee, Kye-Han;Choi, Woo-Jung
    • Korean Journal of Environmental Agriculture
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    • v.30 no.3
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    • pp.229-233
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    • 2011
  • BACKGROUND: Soil acidification, which is known to be one of the reasons of forest decline, is associated with decreases in exchangeable Ca and increases in Al concentration, leading to low Ca/Al ratio in soil solution. As tree rings are datable archives of environmental changes, Ca/Al ratios of annual growth ring may show decreasing pattern in accordance with the progress of soil acidification. This study was conducted to investigate Ca/Al pattern of Pinus densiflora tree ring in an attempt to test its usefulness as an indicator of historical soil acidification. METHODS AND RESULTS: Three P. densiflora tree disks were collected from P. densiflora forests in Jeonnam province, and soil samples (0-10, 10-20, and 20-30 cm in depth) were also collected from the tree locations. Soils were analyzed for pH and exchangeable Ca and Al concentrations, and Ca/Al was calculated. Annual growth rings formed between 1969 and 2007 were separated and analyzed for Ca/Al. Soil Ca/Al was positively (P<0.01) correlated with soil pH, suggesting that soil acidification decreased Ca while increasing Al availability, lowering Ca/Al in soil solution. The Ca/Al of tree rings also showed a decreasing pattern from 18.2 to 5.5 during the period, and this seemed to reflect historical acidification of the soils. CONCLUSION(s): The relationship between soil pH and Ca/Al and the decreasing pattern of Ca/Al of tree ring suggest that Ca/Al of tree ring needs to be considered as a proxy of the progress of soil acidification in P. densiflora forest in southern Korea.

Distribution of Moisture Content in Wood with Vapor Transmission Conditions (투습조건에 따른 목재내 함수율분포)

  • Lee, Weon-Hee;Bae, Hyun-Mi
    • Journal of the Korean Wood Science and Technology
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    • v.28 no.2
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    • pp.3-9
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    • 2000
  • This study concerns the distribution and dependence of moisture content(MC) in wood for same thickness in different vapor transmission conditions. The specimens were disks of 70-mm in diameter and 20-mm in thickness from quartersawn lumber of Korean red pine(Pinus densiflora S. et Z.). The experiments were conducted in ten different conditions on the difference of the vapor pressures by the JIS Z-0208. The distribution of moisture content in wood can be illustrated by two straight lines intersecting at the point of about ten percent Me. On the other hand, when more or less than about 10 percent, the distribution of the Me can be illustrated by one straight lines. Therefore, it is considered that the values of 10 percent Me has no relation to the wood and experimental conditions. It's assumed that 10 percent is the boundary point at which the moisture sorption energy changes. In a previous study, diffusion coefficient is almost constant with no relation to a thickness of the woods for the constant experimental conditions. But, in this study, it seems that diffusion coefficient from the moisture gradient vary with the Me of wood in different vapor transmission conditions.

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The Verification of Image Merging for Lumber Scanning System (제재목 화상입력시스템의 화상병합 성능 검증)

  • Kim, Byung Nam;Kim, Kwang Mo;Shim, Kug-Bo;Lee, Hyoung Woo;Shim, Sang-Ro
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.6
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    • pp.556-565
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    • 2009
  • Automated visual grading system of lumber needs correct input image. In order to create a correct image of domestic red pine lumber 3.6 m long feeding on a conveyer, part images were captured using area sensor and template matching algorithm was applied to merge part images. Two kinds of template matching algorithms and six kinds of template sizes were adopted in this operation. Feature extracted method appeared to have more excellent image merging performance than fixed template method. Error length was attributed to a decline of similarity related by difference of partial brightness on a part image, specific pattern and template size. The mismatch part was repetitively generated at the long grain. The best size of template for image merging was $100{\times}100$ pixels. In a further study, assignment of exact template size, preprocessing of image merging for reduction of brightness difference will be needed to improve image merging.

Shear Performance of PUR Adhesive in Cross Laminating of Red Pine

  • Kim, Hyung-Kun;Oh, Jung-Kwon;Jeong, Gi-Young;Yeo, Hwan-Myeong;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.41 no.2
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    • pp.158-163
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    • 2013
  • Cross laminated timber (CLT) has been an rising issue as a promising building material replacing steel-concrete in mid story rise construction. But, there was no specific standard for CLT because it had been developed in industrial section. Recently, new draft for requirements of CLT was proposed by EN which suggested to evaluate the performance of adhesive in CLT by the same method as glulam. But, it has been reported that shear performance of cross laminated timber is governed by rolling shear. Therefore, block shear tests were carried out to compare parallel to grain laminating and cross laminating using commercial one component PUR (Poly urethane resin). The result showed that the current glulam standard for evaluating bonding performance is not appropriate for CLT. Beacause shear strength of cross laminating decreased to 1/3 of parallel to grain laminating and this strength was representing shear performance of wood itself not the bond. However, cross laminating showed no significant effect on wood failure. Thus, wood failure can be used as a requirement of CLT bonding. Based on the results, cross laminating effect should be included when evaluating adhesive performance of CLT correctly and should be considered as an important factor.

Research on the comparison on the ritual food of Gyeonggi and Gyungsangbuk-do province (경기와 경북지역의 제수 비교 연구)

  • 김정미;장성현;김종군
    • Korean journal of food and cookery science
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    • v.19 no.5
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    • pp.562-570
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    • 2003
  • The awareness of ritual foods in general rituals were surveyed and compared in the Gyeonggi and Gyungsangbuk-do areas in order to identify the characteristics of Korean rituals and establish desirable ritual foods. As materials for "Jeon" (fried pan cakes) in rituals, fish fillets, meat and vegetables were largely used in the Gyeonggi region. In the Gyeongbuk region, all three of these ingredients were the most highly used for "Jeon" also. In the case of rice cakes, "Songpyun" steamed on a layer of pine needles, "Jeolpyun" and "Sirudduk", with a red beans, were mostly used in Gyeonggi-do, while "Songpyun", "Jeolpyun" and "Ingelmi" were largely used in Gyeongsangbuk-do. As seasoned vegetables and herbs, fernbrakes, root of bell flowers, green bean sprouts and bean sprouts were largely used in Gyeonggi-do region, whereas, fernbrakes, bean sprouts, root of bell flowers and spinaches were mainly used in Gyeongbuk region. The use of fernbrakes was highest in both regions. With regard to the number of side dishes, 2∼3 kinds of seasoned herbs and 3∼4 kinds of fruits were mostly used, but with slightly higher numbers in the Gyeongsangbuk-do than the Gyeonggi-do region. With regard to liquor used for rituals, clear strained rice wine was used most in the Gyeonggi-do area, while more unrefined rice wine was used in the Gyeongbuk region. Meat was the most used ingredient in broth slices of dried meat and cod were highly used in the Gyeonggi region, but slices of dried squid were most widely used in the Gyeongbuk region. Most households in both regions tended not to use raw fish in the rituals, and as for the ingredients of Korean Kabobs, meat was the most widely used, then fish and finally vegetables were the most used ingredients. Beef soup was the most used, but more green vegetable soup was used in the Gyeongbuk than the Gyeonggi region. Sweet drink made from fermented rice (sikhe) was generally used in the rituals. It was the most widely used in the Chusok-Hangawi Ritual in the Gyeonggi region, while it was used in the New Year's Ritual in the Gyeongbuk region.