• Title/Summary/Keyword: protection tree

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First Report of Fire Blight Caused by Erwinia amylovora on Korean Mountain Ash (Sorbus alnifolia) in Korea (Erwinia amylovora에 의한 팥배나무 화상병 발생 보고)

  • Yeon-Jeong Lim;Hyeonseok Oh;Mi-Hyun Lee;Eunjung Roh;Hyeonheui Ham;Dong Suk Park;Duck Hwan Park;Yong Hwan Lee
    • Research in Plant Disease
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    • v.29 no.1
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    • pp.79-81
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    • 2023
  • During the nationwide survey of fire blight, the typical shoot blight symptoms were found on Korean mountain ash (Sorbus alnifolia) which was located near an orchard that produced fire blight on pear trees in Eumseong, Korea, May 2021. To identify the causal agent, we progressed isolation from the symptomatic leaves and shoots. Two white and mucoid colonies were isolated into the pure culture. Two isolates were identified as Erwinia amylovora according to the colony-polymerase chain reaction (PCR) with amsB primers and the phylogenetic tree using 16S rRNA sequences. To test of pathogenicity of two isolates, we inoculated immature pear fruits and understock of apple. We observed necrosis and oozes on immature pear fruits and shoot blight resulting in necrosis on apple shoots six days after inoculation. Colonies were recovered from the inoculated pears and apples, and identity was confirmed through colony PCR for amsB genes. To our knowledge, E. amylovora was first reported on Korean mountain ash native to South Korea.

Cultural Characteristics and Genetic Diversity of Rhizina undulata Isolates by Random Amplified Polymorphic DNA(RAPD) (리지나뿌리썩음병균 분리주들의 배양 특성 및 RAPD에 의한 유전적 다양성 분석)

  • Lee, Sang Yong;Lee, Sun Keun;Lee, Jong Kyu;Kim, Kyung Hee;Lee, Seung Kyu
    • Journal of Korean Society of Forest Science
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    • v.95 no.4
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    • pp.388-392
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    • 2006
  • To investigate physiological characteristics and genetic diversity of Rhizina undulata isolates distributed in Korea, cultural characteristics and random amplified polymorphic DNA (RAPD) of 13 Rhizina undulata isolates from Pinus densiflora and P. thunbergi stands were analyzed. There were no correlations between the host species of R. undulata isolates and the mycelial growth of R. undulata isolates on culture media supplemented with water-soluble extract from the two different host species, i.e., Pinus densiflora and P. thunbergi. Genetic diversity of genomic DNA from 13 R. undulata isolates was analyzed by RAPD using 12 random primers. There was no differentiation in RAPD profiles among the isolates from Korea. But, there was some differentiation in RAPD profiles between Korean isolates and Japanese isolates, with 88% homology by phylogenetic tree analysis.

The Reliability Evaluation of TBN Valve Testing Extension in NPP (원자력발전소 터빈밸브 시험주기 연장시 신뢰도평가)

  • Lim, Hyuk-Soon;Lee, Eun-Chan;Lee, Keun-Sung;Hwang, Seok-Won;Seong, Ki-Yeoul
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3221-3223
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    • 2007
  • Recently, nuclear power plant companies have been extending the turbine valve test interval to reduce the potential of the reactor trip accompanied with a turbine valve test and to improve the NPP's economy through the reduction of unexpected plant trip or decreased operation. In these regards, the extension of the test interval for turbine valves was reviewed in detail. The effect on the destructive overspeed probability due to the test interval change of turbine valves is evaluated by Fault Tree Analysis(FTA) method. Even though the test interval of turbine valves is changed from 1 month to 3 months, the analysis result shows that the reliability of turbine over speed protection system meets acceptance criteria of 1.0E-4/yr. This result will be used as the technical basis on the extension of the test interval for turbine valves. In this paper, the propriety of the turbine valve test interval extension is explained through the review on the turbine valve test interval status of turbine overspeed protection system, the analysis on the annual turbine missile frequency and the probability evaluation of the destructive overspeed due to the test interval extension.

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RELIABILITY ANALYSIS OF DIGITAL SYSTEMS IN A PROBABILISTIC RISK ANALYSIS FOR NUCLEAR POWER PLANTS

  • Authen, Stefan;Holmberg, Jan-Erik
    • Nuclear Engineering and Technology
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    • v.44 no.5
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    • pp.471-482
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    • 2012
  • To assess the risk of nuclear power plant operation and to determine the risk impact of digital systems, there is a need to quantitatively assess the reliability of the digital systems in a justifiable manner. The Probabilistic Risk Analysis (PRA) is a tool which can reveal shortcomings of the NPP design in general and PRA analysts have not had sufficient guiding principles in modelling particular digital components malfunctions. Currently digital I&C systems are mostly analyzed simply and conventionally in PRA, based on failure mode and effects analysis and fault tree modelling. More dynamic approaches are still in the trial stage and can be difficult to apply in full scale PRA-models. As basic events CPU failures, application software failures and common cause failures (CCF) between identical components are modelled.The primary goal is to model dependencies. However, it is not clear which failure modes or system parts CCF:s should be postulated for. A clear distinction can be made between the treatment of protection and control systems. There is a general consensus that protection systems shall be included in PRA, while control systems can be treated in a limited manner. OECD/NEA CSNI Working Group on Risk Assessment (WGRisk) has set up a task group, called DIGREL, to develop taxonomy of failure modes of digital components for the purposes of PRA. The taxonomy is aimed to be the basis of future modelling and quantification efforts. It will also help to define a structure for data collection and to review PRA studies.

Vital area identification for the physical protection of NPPs in low-power and shutdown operations

  • Kwak, Myung Woong;Jung, Woo Sik
    • Nuclear Engineering and Technology
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    • v.53 no.9
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    • pp.2888-2898
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    • 2021
  • Vital area identification (VAI) is an essential procedure for the design of physical protection systems (PPSs) for nuclear power plants (NPPs). The purpose of PPS design is to protect vital areas. VAI has been improved continuously to overcome the shortcomings of previous VAI generations. In first-generation VAI, a sabotage fault tree was developed directly without reusing probabilistic safety assessment (PSA) results or information. In second-generation VAI, VAI model was constructed from all PSA event trees and fault trees. While in third-generation VAI, it was developed from the simplified PSA event trees and fault trees. While VAIs have been performed for NPPs in full-power operations, VAI for NPPs in low-power and shutdown (LPSD) operations has not been studied and performed, even though NPPs in LPSD operations are very vulnerable to sabotage due to the very crowded nature of NPP maintenance. This study is the first to research and apply VAI to LPSD operation of NPP. Here, the third-generation VAI method for full-power operation of NPP was adapted to the VAI of LPSD operation. In this study, LPSD VAI for a few plant operational states (POSs) was performed. Furthermore, the operation strategy of vital areas for both full-power and LPSD operations was discussed. The LPSD VAI method discussed in this paper can be easily applied to all POSs. The method and insights in this study can be important for future LPSD VAI that reflects various LPSD operational states. Regulatory bodies and electric utilities can take advantage of this LPSD VAI method.

Influence of Dormancy Level and Carbon Concentration on Freezing Hardiness in Bourse Shoot of 'Fuji' Apple Tree (휴면 정도 및 탄소 함량이 '후지' 사과나무 과대지의 내동성에 미치는 영향)

  • Kweon, Hun-Joong;Park, Moo-Yong;Song, Yang-Yik;Sagong, Dong-Hoon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.18 no.3
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    • pp.151-161
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    • 2016
  • This study was conducted to find out influence of dormancy level and carbon concentration on freezing hardiness in bourse shoot of 'Fuji' apple tree. Bourse shoot of 'Fuji' adult apple tree grafted on M.26 and M.9 rootstocks were used as experimental materials. Dormancy levels of bourse shoot were categorized according to the periods as follows the internal dormancy (late January), the early days after internal dormancy breaking (early February), the late days after internal dormancy breaking (late February), the bud break (late March), and the full bloom (late April). Chilling temperatures with bourse shoot were ranged from 0 to $-40^{\circ}C$. Also, the freezing hardiness according to carbon concentrations were investigated on 'Fuji'/M.9 apple tree that defoliated severely by Marssonina blotch (defoliation) and that of below the average 20 cm in shoot length through heavy crop load (weakness). Results showed that freezing hardiness of bourse shoot may become weaker after internal dormancy breaking. There was no differences in the carbon concentration of bourse shoot of 'Fuji' apple tree grafted on M.9 and M.26, so may be resulted in no difference in freezing hardiness both of bourse shoot grafted on M.9 and M.26 rootstock. Carbon concentration in bourse shoots with weakness and C/N ratio in bourse shoots with defoliation were lower than that of healthy. It may be shown that the freezing hardiness of defoliation and weakness were weaker than that of healthy.

Tree Trunk Level Distribution of Entry Hole by Platypus koryoensis (Coleoptera: Platypodidae) and Its Implication to Tree Damage (광릉긴나무좀(Coleoptera: Platypodidae)의 수간내 분포와 참나무 피해)

  • Choi, Won-Il;Lee, Jung-Su;Choi, Kwang-Sik;Kim, Jong-Kuk;Shin, Sang-Chul
    • Korean journal of applied entomology
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    • v.47 no.2
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    • pp.127-131
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    • 2008
  • Ambrosia beetle, Platypus koryoensis, is a vector of oak wilt disease caused by Raffaelea sp. in Korea. The degree of damage by oak wilt disease was dependent on the density of the beetles in the oak trunk, a relationship between the degree of damage by oak wilt disease and the density of beetle on the basis of the number of entry hole was studied. Entry hole distribution within tree trunk was analyzed by the nearest neighbor method. Thirty four oak trees (Quercus mongolica) located in survey area were selected and then degree of damage, the number of attack hole/$623cm^2$ in upper (50cm from the surface) and lower (surface) trunk and the nearest neighbor distance between the holes were measured. The number of hole and the nearest neighbor distance in upper and lower part were positively correlated with each other. As the degree of damage was severer, the number of the holes increased, whereas the nearest neighbor distance decreased. The distribution pattern of the hole was changed from clumped one to uniform as the severity of damage increased. These results suggested that Platypus koryoensis attacked the oak tree in concentrative manner at initial stage of attack but at final stage, it distributed uniformly to reduce intraspecific competition between the beetles.

Diagnosis of the growth status and actual condition of the remaining old trees in the village - Focused on Hyeongok-myeon in Gyeongju-si - (마을 내 잔존 노거수의 생육현황 및 실태진단 - 경주시 현곡면을 중심으로 -)

  • Kim, Young-Hun;Deng, Bei-Jia;Chen, Geng;You, Ju-Han
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.23 no.6
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    • pp.109-123
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    • 2020
  • The purpose of this study is to provide basic data for the establishment of future countermeasures by diagnosing the growth status and actual condition of undesignated old trees distributed in Hyeongok-myeon, Gyeongju, Gyeongsangbuk-do. The number of old trees surveyed was 2 weeks in Gajeong-ri, 2 weeks in Haguri, 3 weeks in Nae-Tae-ri, 1 week in Nawon-ri, 6 weeks in Oryu-ri, 3 weeks in Sangguri, and 2 weeks in Sohyeon-ri, The trees species composition was 6 trees Celtis sinensis Pers., 1 Diospyros lotus L. trees, 4 trees Salix chaenomeloides Kimura trees, 2 Styphnolobium japonicum L. trees, and 7 Zelkova serrata (Thunb.) Makino trees. Growth status is 7.1~22.0m in height, 14.6~25.1m in long axis, 10.2~19.2m in short axis, root diameter is 76.0~236.4cm, diamter at breast height is 67.0~220.0cm, soil acidity is pH4.9~7.0, soil The hardness was measured to be 4.0-27.0mm. The result grade of the scoring data of health information is represented by monitoring generally, monitoring critically, and absolute monitoring, and it was confirmed that out of the 20 trees population in Hyeongok-myeon, the general monitoring grade was 7 weeks, the major monitoring grade was 13 weeks, and there was no absolute monitoring grade. Accordingly, the number of old trees of the general surveillance level was maintained at the current level, and ecological surgical operations were introduced for the major surveillance level, but the case of village forests should be different, and sequential treatments were the old tree urgently needed. The level and bark of the target tree, the state of the crown, the root exposure, the presence of pests and pests, the vitality and the ground condition, the degree of pollution are normal, poor, or very poor, operation and protection management, soil improvement, removal of cover, and disinfection were urgently needed for the old trees with the surveyed data. In order to compensate for these matters, continuous monitoring and management measures for the old number should be sought.

Assessment of physical condition of old large Chionanthus retusus(Chinese Fringe Tree) using structural stability analysis (천연기념물 이팝나무 노거수 구조안정성 진단을 통한 물리적 생육상태 평가)

  • SON Jiwon;SHIN Jinho
    • Korean Journal of Heritage: History & Science
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    • v.56 no.1
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    • pp.118-130
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    • 2023
  • Decay or large cavities inside trees are the main causes of trees overturning and broken branches, and structurally weakened trees are more vulnerable to strong winds and heavy snowfall. Recently, as strong winds and typhoons increase due to climate change, the damage to human life and property due to trees overturning continues to increase, and cultural assets are in a similar situation. In particular, old big trees are structurally vulnerable to external shocks such as strong winds and heavy snowfall. This study was aimed at providing a scientific basis for preventive protection measures by conducting a structural stability diagnosis of seven retusa fringe trees designated as natural monuments. For the structural stability diagnosis, tree risk assessment and internal tree defect measurements were performed. As a result of the tree risk assessment, the Retusa Fringe Trees in Sinjeon-ri, Yangsan and Gwangyangeupsu had the highest risk of broken branches due to weak branch attachment strength. As a result of the diagnosis of internal defects of cross sections of measured trees, there were suspected cavities or severe decay in all except two trees of the population of Retusa Fringe Trees in Pyeongji-ri. Natural disasters due to climate change are increasing, and the scale is getting larger, so it is very important to preemptively manage large old trees through scientific structural safety diagnosis to manage trees that are vulnerable to environmental changes.

Mass-rearing Techniques of Anastatus orientalis (Hymenoptera: Eupelmidae), as the Egg-parasitoid of Lycorma delicatula (Hemiptera: Fulgoridae): An Using Method of Antheraea pernyi (Lepidoptera: Saturniidae) and L. delicatula Eggs in Laboratory (꽃매미 알 기생천적인 꽃매미벼룩좀벌의 대량사육기술: 산누에나방과 꽃매미 알 활용 방법)

  • Seo, Meeja;Kim, Jeong Hwan;Seo, Bo Yoon;Park, Changgyu;Choi, Byeong Ryeol;Kim, Kwang Ho;Ji, Chang Woo;Cho, Jum Rae
    • Korean journal of applied entomology
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    • v.57 no.4
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    • pp.243-251
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    • 2018
  • Eggs, immature eggs, and pupae of 8 different insects (Halyomopha halys, Riptortus pedestris, Lymantria dispar, Antheraea yamamai, Verlarifictorus spp, Antheraea pernyi, and Musca domestica) including Lycorma delicatura were used to select the alternative host for laboratory mass rearing of A. orientalis. Except L. delicatula's eggs and immature eggs of A. pernyi, other 7 tested insects were not parasitized by A. orientalis. A. pernyi was reared with oak tree leaves and its cocoons were harvested on mid-July and early October. On 4 or 5 days after emergence, only female adults showing swollen abdomen were collected and stored at $1{\sim}5^{\circ}C$. We could get 150~200 eggs per one female by dissecting the female's abdomen. For examining the possibility for laboratory mass rearing of A. orientalis with A. pernyi's immature eggs, developmental periods from egg to pupa between the two different hosts were compared. Developmental periods were 36.1 days on immature eggs of A. pernyi and 36.8 days on an original host's eggs, respectively. The number of parasitized eggs by A. orientalis' female for 24 h was 3.4 on immature eggs of A. pernyi and 4.2 on an original host's eggs, respectively. However, there were no significant statistical differences in developmental period and parasitization between the two hosts. By supplying honeyed water to newly emerged female parasitoids, it was able to maximize their longevities up to 64.3 days after emergence. Therefore, our results support potential for laboratory mass-rearing of A. orientalis using A. pernyi's immature eggs as an alternative host.