• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.302-306
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• 2016

There are various methods to evaluate tree vigor. Cambial electrical resistance represents tree vigor using the method of electrophysiological diagnosis. This study investigated the vigor of several tree species using Shigometer, and compared the differences among the species. The factors, such as foliation, trunk orientation and bark temperature, which affect electrical resistance were also investigated. The needle penetration into cambium was controlled to keep the depth consistent in order to minimize measurement error. Each of three trees were selected from Zelkova serrata, Ginkgo biloba, Metasequoia glyptostroboides, Pinus koraiensis, and Liriodendron tulipifera. The electrical resistances were measured at 60 and 120 cm height of the stem in 4 directions from March until May 2011. The soil conditions in surrounding areas and tree stress responses were also measured. The results were analyzed for the relationship between electrical resistance and the affecting factors. The electrical resistance showed a relatively higher level before foliation until mid-March. The values started to decline from April and recorded a minimal level on May 11. The changes of soil moisture, soil electric conductivity, and tree stress responses during the measurement period showed a similar trend to that of electrical resistance. The Pinus koraiensis, an evergreen conifer, showed few changes on the electrical resistance values during the measurement period. Zelkova serrata, Ginkgo biloba, and Metasequoia glyptostroboides showed the highest bark temperatures and lowest electrical resistances at their south-facing stem. Shigometer can provide measures simple to assess tree vigor in the fields, and to the management of trees.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.408-412
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• 2010

내화수림대 조성을 위하여 난대수종 중 내화성 수종을 선발하고자 콘칼로미터를 이용하여 5수종(감탕나무, 구실잣밤나무, 동백나무, 붉가시나무, 후박나무)을 대상으로 수피, 가지, 생엽 등 부위별 연소특성을 분석하였다. 난대수종의 평균 열방출율(HRR)은 감탕나무($167.66kW/m^2$)>구실잣밤나무($142.80kW/m^2$)>동백나무($116.78kW/m^2$)>후박나무($95.48kW/m^2$)>붉가시나무($79.80kW/m^2$) 순으로 나타났다. 따라서, 붉가시나무가 산불 발생시 다른 수종에 비해서 화재강도가 낮은 것으로 사료된다. 수종별 부위(생엽, 가지, 수피)의 착화특성을 분석한 결과, 생엽에서 최초자연발화온도는 동백나무, 감탕나무($697^{\circ}C$)>후박나무($672^{\circ}C$)>구실잣밤나무($663^{\circ}C$)>붉가시나무($658^{\circ}C$) 순으로 나타났으며, 가지에서는 구실잣나무($671^{\circ}C$)>후박나무($669^{\circ}C$)>감탕나무($661^{\circ}C$)>붉가시나무($657^{\circ}C$)>동백나무($591^{\circ}C$) 순으로 나타났으며, 수피에서 동백나무($839^{\circ}C$)>후박나무($804^{\circ}C$)>동백나무($784^{\circ}C$)>붉가시나무($780^{\circ}C$)>감탕나무($749^{\circ}C$) 순으로 나타났다. 수종별 부위에 있어서 최초자연발화온도가 다른 것은 수종에 따라 조직과 세포간극 형태에 따라 수분함량의 차이가 착화특성을 다르게 나타내는 것으로 사료된다.

• Journal of the KSME
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• v.21 no.1
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• pp.21-31
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• 1981

원자력발전소의 원자로냉각재 압력경계의 건전성과 안정성을 확보하기 위하여 법적 요구조건을 설정함에 있어 파괴역학이 어떻게 적용되었는 가를 설명하였다. 이를 요약하면 다음과 같다. 1) 압력경계에 사용되는 재료의 $RT_{NDT}$를 정의하였다. 이는 무연성천이온도와 같은 개 념의 것으로, 앞으로 재료의 파괴인성은 이 $RT_{NDT}$에 대한 상대온도의 함수로 주어진다. 2)비연성파괴를 방지하기 위한 설계조건으로서 선형탄성 파괴역학에 근거한 조건식을 인용하였다. 여기서 조건식이란 능력확대계수의 합계가 어떠한 조건에서도 이러한 조건식을 만족한다는 것을 해석적으로 확인하고 규제당국의 승인을 받아야 한다. 3) 가동중검사에 발견된 결함으로 합격수준을 초과하는 것은 파괴역학적으로 해석하여 구조적 으로 안전하다는 것은 파괴역학적으로 해석하여 구조적으로 안전하다는 것을 입증하여야 한다. 이때 결함은 원자로의 가동과 더불어 성장하므로 수명기간중 피로파괴에 이를 것인지의 여부도 평가하여야 한다. 이때의 대조균열성장률은 Paris의 power law에 따른다. 4) 고속중성자 (E>1. 0MeV)에 의한 조사취화를 감시하기 위하여 감시시험계획을 사전에 수립 하고 이에 따라 감시시험을 수행하여 조사에 수립하고 이에 따라 감시시험을 수행하여 조사에 의한 원자로용기 재료의 파괴인성의 저하를 평가하여 이를 고려한 충분한 안전여유를 갖는 운 전조건 즉, 압력-온도 한계곡선을 산출하여야 한다. 이때의 취화 정도는 DELTA. $RT_{NDT}$ 와 Upper Shelf Energy의 감소로 나타낸다. 또한, 압력-온도 한계곡선은 선형관성 파괴역학에 입각한 조건식을 이용하여 해당 온도에서의 압력을 산출한다. System을 개발 사용하기 위하여 기존 전자계산소를 이용하는 방법이 바람직하며 System의 도입은 자체운영을 결정하기 전에 경제적인 여건 등 여러가지 문제를 검토하여야 한다. 특히 Turn Key Base로 System를 도입할 경우에는 System의 도입목 적과 사용빈도, 앞으로의 확장성 현재 설계및 생산 과정과의 마찰가능성, 유지보수문제 등을 신 중히 검토하여야 한다. 이제 기계공업도 전자계산기를 이해하고 사용하므로 서 발전할 수 있는 단계가 되었다. 예로부터 좋은 공구를 개발하여 적절히 사용하는 것이 기계공업 발전의 첩경이 었다. 전자계산기는 현대 기술이 개발한 가장 강력하고 사용하기 좋은 공구이다.점에서 피로구열의 안정성장을 논하고, 과거 10여년간의 피로 crack문제에 대한 연구방법, 실험방법 등을 소개하는 방향으로 고 를 진행시켜 나가겠다.에 그 효과가 증대됨을 알 수 있었다.적용한 임상실험이 수행되어야 할 것이다. 또한 위치결정에서 획득한 좌표값의 정확성을 알아보기 위해서 팬톰을 이용한 방사선조사 실험이 추후에 실행되어져야 할 것이다. 그리고 제작된 프레임에 Rotating X선 시스템과 내부 장기의 움직임을 계량화하고 PTV에서의 최적 여유폭을 설정함으로써 정위 방사선수술 및 3 차원 업체 방사선치료에 대한 병소 위치측정과 환자의 자세에 대한 setup 오차측정 결정에 도움이 될 수 있을 것이라고 사료된다. 상대적으로 우수한 것으로 나타났으며, 혼합충전재는 암모니아의 경우 코코넛과 펄라이트의 비율이 7：3인 혼합 재료 3번과 소나무수피와 펄라이트의 비율이 7：3인 혼합 재료 6번에서 다른 혼합 재료에 비하여 우수한 것으로 나타났다. 4. 코코넛과 소나무수피의 경우 암모니아 가스에 대한 흡착 능력은 거의 비슷한 것으로 사료되며,

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.308-312
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• 2008

In this study, we have carried out test to examine the ignition characteristics, such as a relation of moisture content and combustibility, and ignition temperature using KRS-RG-9000 tester, of significant part of above trees which are representative species of Young Dong Province of Korea. After rainfall, the percentage of moisture content of living leaves and branches was between 52 and 70%. But it was just between 17 and 33% after 144 hours drying at normal temperature. For dead leaves, it was 10% lower than of first. There was a significant difference on ignition characteristics. The hazard of ignition is highest on dead leaves. The ignition temperature of barks and branches is higher so a retard time is long than of living and dead leaves at normal temperature.

• KSBB Journal
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• v.11 no.1
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• pp.71-76
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• 1996

Studies were carried out to examine some factors affecting the supercritical carbon dioxide extraction of taxol from the bark of Taxus cuspidata using a continuous packed bed extractor. The factors investigated in this study were pressure, temperature, volume of carbon dioxide, and co-solvent. It was found out that the amount of taxol extracted was not significantly affected by the operating pressure in the absence of a co-solvent although it increased by about 20% at 5500 psig. With $24\ell$ of carbon dioxide the saturated amount of taxol was extracted at 318K and 5500psig. Methanol was found to be the most effective co-solvent in terms of amount of taxol extracted among six different co-solvents used. When methanol was used as a co-solvent the effect of operating pressure became significant; approximately 50% increase in the amount of taxol extracted was observed at 3000 psig as compared to at 2500 or 3500psig. The optimum methanol concentration in supercritical fluid was 13% (w/w)at 308K, 3000psig.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.98-103
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• 2010

This study was carried out on the composting of the most part of the plant waste materials inflowed-drifting into the dam during the localized heavy rain and the rainy season, due to the abnormal climate change, and for the sewage sludge banned to dispose legally into the ocean from the year of 2012. It was analysed the distinctive physicochemical qualities of the compost with treatment S-1(dam suspended particle sawdust : oak tree bark : sewage sludge : chicken manure = 30 : 20 : 40 : 10) and treatment S-2(dam suspended particle sawdust : oak tree bark : sewage sludge : chicken manure = 30 : 30 : 30 : 10). Both S-1 and S-2 maintained for 10 days at above $65^{\circ}C$ of the compost pile temperature, and the most of its pathogen were destroyed. In case of pH, until the 90th day into composting, S-1 with the pH value of 7.78 was slightly higher than S-2. The C/N value of S-1 was 15.3 and that of S-2 was 16.9. The quality of its final product was satisfied to the manufacture-standards. The GI value of S-1 was 91 higher than that of S-2, which was 84. In conclusion, it is highly recommendable to manufacture S-1 for its frequent usage of dam suspended particle sawdust and sewage sludge, and for its excellent quality and safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.1
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• pp.97-103
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• 2015

This study investigated changes in phenolic contents of different parts of Rhus verniciflua Stokes (RV) according to extraction conditions. Bark and xylem parts of RV were extracted at 80, 100, 120, 140, and $160^{\circ}C$ for 1, 3, and 5 h, respectively. Major phenolic compounds (gallic acid, protocatechuic acid, fustin, fisetin, sulfuretin, and butein) of RV were analyzed. The gallic acid, fisetin, sulfuretin, and butein contents significantly increased as extraction temperature increased. Protocatechuic acid and fustin contents increased as increasing extraction temperature to $120^{\circ}C$ and decreased afterward. The gallic acid, protocatechuic acid, and butein contents of bark were higher than those of xylem extracts. The optimal extraction conditions of gallic acid, protocatechuic acid, fustin, fisetin, sulfuretin, and butein were $160^{\circ}C/3h$ (380.22 mg%), $120^{\circ}C/1h$ (9.25 mg%), $100^{\circ}C/3h$ (206.97 mg%), $140^{\circ}C/5h$ (93.84 mg%), $140^{\circ}C/5h$ (16.07 mg%) and $160^{\circ}C/5h$ (1.49 mg%), respectively. These results suggest that the optimum extraction temperature and time considering RV extraction yield and cost are $140^{\circ}C$ and 3 h, respectively.

• Journal of Korean Society of Forest Science
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• v.77 no.3
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• pp.294-302
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• 1988

The experiment was carried out to investigate the properties of bark extractives form Larix epilepsies and to evacuate their suitability as a bonding agent. The yield and reactivity were measured to examine the influence of temperature and time and the effect of carbonation and sulfonation. To define the possibility of practical application as wood adhesives the viscosity and gelation time were measured at 33% concentration. The results obtained were summarized as follows : 1. As the both yield and reactivity were high, extraction for 2 hours at $80^{\circ}C$ was the optimal temperature and time. 2. The highest effect achieved at 1% $Na_2CO_3$ about carbonation and 1% $Na_2SO_3$ : $NaHSO_3$ and 0.25% $Na_2SO_3$ about sulfonation. The sulfonation of 0.25% $Na_2SO_3$ increased the yield and reactivity most highly. 3. By using hot water as extraction liquid the yield was 17.2%, while the addition of 1% and 5% NaOH to the extraction liquid increased the yield to 38.6% and 44.6%, respectively. 4. Hot water extracts showed the highest reactivity(68.8%). The addition of 1% and 5% NaOH led to decrease in reactivity(49.3% and 25.8%, respectively). 5. At 33% concentration of the extracts the viscosity appeared very variable. Significantly high values of viscosity was measured in 1% NaOH solution, while very low values appeared for 5% NaOH solution. 6. The shortest gelation time was determined at pH 7 to 10 and the highest at pH 4. The use of paraformaldehyde resulted in gelation times longer than those of 37% formaldehyde solution. 7. Except the sulfonation extracts of hot water and 1% NaOH, the other extracts were found unsuitable due to high viscosity(1% NaOH extracts, sulfonation extracts) or to curing inability(5% NaOH extracts, sulfonation extracts of 5% NaOH). 8. From the three extract solutions which appeared to be suitable for use as bonding agents the hot water extracts and the sulfonation extracts of hot water were superior in extract reactivity, while the sulfonation extracts of 1% NaOH exceeded the other two extracts in extract yield.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.11
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• pp.1776-1782
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• 2013

Rhus verniciflua was extracted at different temperatures and times, and the extracts were evaluated for contents of total phenolics and flavonoids, and antioxidant activities using DPPH and ABTS radical scavenging activities. Extraction temperatures and times were 80, 100, 120, 140 and $160^{\circ}C$, and 1, 3 and 5 hr. The total phenolic and flavonoid contents as well as antioxidant activities by DPPH and ABTS increased as the extraction temperature increased. The total phenolic contents did not significantly increase at less than $100^{\circ}C$ with different extraction times. However, they were increased at 3 hr and decreased at more than $120^{\circ}C$. The total flavonoid contents reached a high value of 8.04 mg CE/g at $140^{\circ}C$. The antioxidant activity by DPPH increased as the extraction temperature increased and reached high values of 34.28 mg TE/g at $140^{\circ}C$. The total antioxidant activity by ABTS was similar to DPPH. These results presumed that the optimum extraction temperature and time in the process of Rhus verniciflua extraction are $140^{\circ}C$ for 3 hr.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.15-21
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• 2006

The objective of this research is to develop the technique for carbonization of wood pellet and analyze a possibility for the utilization of carbonized wood pellet. The properties of wood pellet charcoals, such as density, yield, elemental composition, higher heating value, and methyleneblue adsorption, were analyzed. Wood pellet was made of sawdust of Hyunsasi-poplar, Japanese larch, Korean pine, Korean red pine, and Jolcharn-oak (serrate oak), respectively. The high density charcoal ($0.5{\sim}0.7g/cm^3$) was yielded from densified wood pellet. The carbon contents and calorific values of wood pellet charcoals were increased with the increase of carbonization temperature. The methyleneblue adsorptivity of wood pellet charcoal was similar to that of wood charcoal.