• Title/Summary/Keyword: Stand damage

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Changes in Forest Disturbance Patterns from 1976 to 2005 in South Korea

  • Park, Pil Sun;Lee, Kyu Hwa;Jung, Mun Ho;Shin, Hanna;Jang, Woongsoon;Bae, Kikang;Lee, Jongkoo;Lee, Don Koo
    • Journal of Korean Society of Forest Science
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    • v.98 no.5
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    • pp.593-601
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    • 2009
  • Forest disturbances including forest fire, insect pests and diseases, landslides, and forest conversion from 1976 to 2005 were investigated to trace the changes of major forest disturbance agents and their characteristics over time in accordance with changes in natural and social environment in South Korea. While the damaged area by insect pests and diseases continuously decreased for the past 30 years, damaged areas by forest fire and landslide were fluctuating through years. The interval of large forest fires has become shorter with increased tree volume. The precipitation between January and April were significantly correlated with large fire occurrences as Pearson's correlation coefficient -0.400 (P=0.029). The composition of major insect pests and diseases damaging Korean forests has been changed continuously, and become more diversified. While damages by pine caterpillar (Dendrolimus spectabilis) and pine needle gall midge (Thecodiplosis japonensis) decreased, damage by introduced pests has been more serious recently. The change of precipitation pattern that brought more localized heavy rain or powerful typhoon resulted in the recent increase in landslide areas. The major land uses to induce forest conversion have been changed, reflecting the changes in industrial structure in South Korea as agriculture and mining in 1970s, mining and golf ranges classified in pasture in 1980s, and road and housing construction in 1990s and 2000s. Changes in forest disturbance patterns in South Korea show that a country's industrial development is jointly working with global warming on forest stand dynamics. Altering energy structure and land use pattern induced by industrial development accumulates forest volume and reforms microenvironments on forest floor, interacting with climate change, inducing shorter interval of large forest fire and changes in major species composition of forest insect pests and diseases.

Aeroelastic modeling to investigate the wind-induced response of a multi-span transmission lines system

  • Azzi, Ziad;Elawady, Amal;Irwin, Peter;Chowdhury, Arindam Gan;Shdid, Caesar Abi
    • Wind and Structures
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    • v.34 no.2
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    • pp.231-257
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    • 2022
  • Transmission lines systems are important components of the electrical power infrastructure. However, these systems are vulnerable to damage from high wind events such as hurricanes. This study presents the results from a 1:50 scale aeroelastic model of a multi-span transmission lines system subjected to simulated hurricane winds. The transmission lines system considered in this study consists of three lattice towers, four spans of conductors and two end-frames. The aeroelastic tests were conducted at the NSF NHERI Wall of Wind Experimental Facility (WOW EF) at the Florida International University (FIU). A horizontal distortion scaling technique was used in order to fit the entire model on the WOW turntable. The system was tested at various wind speeds ranging from 35 m/s to 78 m/s (equivalent full-scale speeds) for varying wind directions. A system identification (SID) technique was used to evaluate experimental-based along-wind aerodynamic damping coefficients and compare with their theoretical counterparts. Comparisons were done for two aeroelastic models: (i) a self-supported lattice tower, and (ii) a multi-span transmission lines system. A buffeting analysis was conducted to estimate the response of the conductors and compare it to measured experimental values. The responses of the single lattice tower and the multi-span transmission lines system were compared. The coupling effects seem to drastically change the aerodynamic damping of the system, compared to the single lattice tower case. The estimation of the drag forces on the conductors are in good agreement with their experimental counterparts. The incorporation of the change in turbulence intensity along the height of the towers appears to better estimate the response of the transmission tower, in comparison with previous methods which assumed constant turbulence intensity. Dynamic amplification factors and gust effect factors were computed, and comparisons were made with code specific values. The resonance contribution is shown to reach a maximum of 18% and 30% of the peak response of the stand-alone tower and entire system, respectively.

Wind Stability of Commercially Important Tree Species and Silvicultural Implications, Daegwallyeong Korea (대관령 지역 경제림에 대한 내풍 안정성 분석 및 임업적 적용)

  • Moktan, Mani Ram;Kwon, Jino;Lim, Joo-Hoon;Shin, Moon-Hyun;Park, Chan-Woo;Bae, Sang-Won
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.17 no.1
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    • pp.58-68
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    • 2015
  • This study compares the wind stability of Larix kaempferi (Lamb.) Carr., Pinus koraiensis Sie. & Zucc. and Abies holophylla Maxim. to understand and inform wind risk management of these plantation trees at Daegwallyeong, Korea. Temporary square plots of $20m{\times}20m$ ($400m^2$) were laid out, and DBH (Diameter at Breast Height) and height for trees greater than 10 cm in DBH were measured by species. A total of 15 plots with 5 plots each in L. kaempferi, P. koraiensis and A. holophylla stands were sampled at random. Among the species, A. holophylla and P. koraiensis have comparatively lower h/d (Height/DBH) ratios than L. kaempferi. These results indicate that the former two species are more wind firm than the latter species. About 9% of the L. kaempferi trees have higher h/d ratios than the critical threshold limit 80. These trees are vulnerable to wind damage and should be removed in the next thinning regime. The analysis of variance detected a significant difference (p < 0.05) in the h/d ratios and Gini coefficient indicating species differences and DBH size variation, respectively. Gini coefficient was 16.4% in A. holophylla, 15.9% in P. koraiensis and 14% in L. kaempferi stands indicating limited DBH size variation. Lower h/d ratios are attributed to thinning in these stands and tree morphological differences. To increase wind firmness, low thinning should concentrate to remove trees with the h/d ratio above 80 coinciding at the time of stand distinction phase. Forest managers and practitioners should measure and maintain h/d ratios of trees below the critical threshold limit of 80 through stand density management. Variable density thinning approach should be tested to increase tree DBH sizes of the even-aged stands.

Effect of Methiocarb Singles and Mixtures on Bird-repelling and Seedling Growth in Water-seeding Rice (담수 직파 벼에 있어서 Methiocarb 단제 및 Thiram 혼합제가 새 피해 경감과 모의 생육에 미치는 영향)

  • 이철원;송범헌;정봉진
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.42 no.4
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    • pp.378-383
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    • 1997
  • Bird damages are often occurred at the seeding and seedling stages of crops. What the bird damage is preventing from the seeding and seedling of rice in the paddy would be very important to get high yield. Methiocarb was formulated as a bird repellent of crop seeding and seedling. Its effects on the seedling growth, related to the chemical injuries and the bird damages, were examined at the seeding and seedling growth stages of Anjungbyeo(Oryza sativa L.) with different types and amounts of methiocarb treatment in both pot and field experiments. In the pot experiment, bird damages were not occurred at all treatments of methiocarb, while bird damages were occurred at the control; 30, 85, and 100% of damages at 5, 10, and 15 days after seeding, respectively. The ratio of seedling stand was not significantly different among all of treatments, methiocarb, methiocarb+thiram, and control. However, the plant height and the number of seedling leaves at 15 days after seeding was shortened and lowered statistically more at treatment of methiocarb 15g than those of methiocarb 10g and control. The plant height at 35 days after seeding, showing the recovery degrees of chemical injuries, was significantly lowered in treatment of methiocarb+thiram 15g, whereas the plant height of methiocarb FS 15g was not significantly differed from that of the control. In the field study, the bird damages were significantly reduced in treatment of methiocarb compared to that of the control. The plant height and the number of leaves at 25 days after seeding were not differed statistically among all of treatments. The chemical injuries were occurred in all treatments of methiocarb at 10 days after seeding, while they were not shown at 20 days after seeding.

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The Study on Restoration & Repair of the Seated Stone Statue of Buddha in the Samreoung Valley of Mt. Namsan (경주 남산 삼릉계 석불좌상 보존 및 복원 연구)

  • Jeong, Min Ho;Ji, Sung Jin
    • Korean Journal of Heritage: History & Science
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    • v.43 no.3
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    • pp.242-281
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    • 2010
  • There are a large number of Buddhist cultural relics in Mt. Namsan. The cultural relics carry the spirit of people of Shila who dream of Buddhist Elysium and the establishment of Buddhist nation. In the valley and the top of the mountain and on various rock cliff, stone statues of Buddha and stone pagodas stand in harmony with nature. For that reason, Mt. Namsan is called an open-air museum. And it played an important role in establishing 'The UNESCO World Heritage' status for Gyeongdju in December 2000. But sadly, there are many stone relics that have eroded away and damaged from collapsing in the passage of time. The seated stone statue of Buddha in Samreoung valley of Mt. Namsan is one of them. It was created between the 8th and 9th century, and restored without much care nor extensive historical research in 1923. As a result, The face of the Buddha remained with concrete mortar and its nimbus fallen backward and destroyed. Therefore, restoration and repair as well as creation of a statue environment for the statue were urgent. So we immediately started in restoration and repair. First, through the archaeological excavation around the stone Buddha, we carried the stone Buddha on the original position. In order to restore the statues to its original glory created by the Unified Shila Dynasty, we created a restoration plan in corporation with art historians and historians, then restored the jaw and the damage nimbus. Second, we made the weathering & damage map of the stone Buddha. In order to prevent second damage, we cleaned the surface of contaminants with distilled water. Third, we studied restoration method to prevent artificial damage. We recreated parts of his face and halo. Then each parts of the statue were restored to their original position. In the whole process of restoration, we tried to use traditional techniques.

Effect of Sorbitol on the Texture and the Survival of Lactic Acid Bacteria of Frozen Yoghurt (Sorbitol첨가가 Frozen Yoghurt중 유산균의 생존율과 조직에 미치는 영향)

  • Kim, Eung-Ryul;Kim, Yu-Seong;Lee, Yeong-Geon;Ju, Ji-Seon;Lee, Gang-Ik;Baick, Seung-Cheon;Lee, Jong-Ik;Yu, Je-Hyeon
    • Journal of Dairy Science and Biotechnology
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    • v.14 no.1
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    • pp.71-84
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    • 1996
  • This study was conducted to examine the usability of sorbitol for the manufacture as low-calory ingredient and cryoprotectant against frost damage. When frozen yoghrt was made of replacing sucrose by sorbitol at yoghurt mix, the change of physicochemical and lactic acid bacteria, such as Str. thermophilus, L. bulgaricus, and mixed culture of Str. thermophilus, and L. bulgaricus(1:1), was studied during the frozen storage(-20$^{\circ}$C). During the incubation of yoghurt mix, the rapid growth of lactic acid bacteria in all sample was observed as the increase of sorbitol addition, but sample A and D were almost similar. This results suggested that sucrose could play role of effecting the growth stimulator, otherwise, sorbitol could inhibit the death of microorganism, following the genus. At the survival rate between lactic acid bacteria during freezing of -5$^{\circ}$C by ice cream freezer Str. thermophilus showed 26.19 to 34.76%, L. bulgaricus 3.97 to 5.20%, and mixed culture 17.16 to 40.87% respectively. L. bulgaricus showed the greater lethal rate than other genus. Sample C which mixed sucrose with sorbitol (1:2 ratio) was showed the lowest lethal rate. Therefore, it suggested that the use of this ration could be used for better anti-frost damage. During the storage of -20$^{\circ}$C, the number of lactic acid bacteria generally decreased in the stand point of genus and frozen storage period. The survival of lactic acid bacteria might be the addition of sorbitol which could have the effect of anti-forst damage. In all treatment, lactase activity showed the rapid decrease after freezing. During the period of frozen storage, it was shown the slow decreasing trend. In spite· of decreasing, the result during yoghurt mix incubation -5$^{\circ}$C freezing, and -20$^{\circ}$C frozen storage was different at the level. After 80 days of storage, the lactase activity was similar among all genus and sample. Despite differenting viscosity followed by genus, combination of mix, and pH, the ratio of 1 to 2(sucrose : sorbitol) showed the greatest viscosity. The water holding capacity of frozen yoghurt mix was closely related to viscosity. As increasing sorbitol amounts, hardness and cohesiveness were increased, but elastisity was decreased. The significant differences between sample was inoculated with Str. thermophilus. However, there were not significant difference from the sample inoculated with L. bulgaricus and mixed culture.

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Survey on Comparative Awareness between Media and Industry on Occurrence of Food Safety Incident (식품안전사건 발생 시 미디어와 산업의 인식도 조사)

  • Shin, Won-Jung;Lee, Yu-Si;Oh, Se-Ra;Park, Tae-Gyun;Kim, Renee;Kim, Ho-Sik;Lee, Jung-Ho;Lee, Seung-Yong;Ha, Sang-Do
    • Journal of Food Hygiene and Safety
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    • v.28 no.2
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    • pp.108-114
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    • 2013
  • To describe the comparative awareness between media and industry, we conducted a survey with a professional group including 28 food safety managers at food corporations and 17 food journalists to find out the differences in perception of 'reporting terms' and 'correspondence terms' when food safety incident occurs. We surveyed by questionnaire methods and did the statistical analysis by SPSS. The results showed that 70.6% of the journalists and 92.9% of the corporation workers answered 'yes indeed' about the question whether the media has a great influence when food safety incident occurs. In the perception that use of the stimulating terms of the media was the cause of company damage, 83% of the corporate workers answered 'yes indeed', and 70.6% of the journalists answered 'yes'. It means that both groups agreed on stimulating terms causing company damage. In the question whether the 'reporting terms' of the media and the 'correspondence terms' of the government and academia made a difference in the consumers' perception and the spread of the incident, 92.9% of the corporate workers and 35.3% of the journalists answered 'yes indeed'. It means that both groups showed a common opinion that the difference in choice of words expanded the perception of consumers, and the spread of the incident. However, the corporate workers agreed with this in a more serious manner than the journalist group. In standardization of 'reporting terms' and restricting use, corporate workers were overall at a positive stand while journalists showed a big difference in opinion within the group. In conclusion, it is necessary to establish a measure to standardize the terms used by corporations, journalists, and professionals in order to decrease the differences of terms and the damage of consumers and the company when food safety incident occurs.

Process of Coping with Domestic Violence of Marriage Immigrant Women (결혼 이주 여성의 가정폭력 대처과정에 관한 근거이론 접근)

  • Ko, Ki-Sook;Jeong, Mee-Kyung
    • The Journal of the Korea Contents Association
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    • v.12 no.10
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    • pp.254-279
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    • 2012
  • This research aims to suggest a practical solution in order to make marriage immigrant women free from violence and stand on their own. The suggestion could be made by developing Substantive theory in terms of marriage immigrant women's coping with domestic violence. The research question is; How marriage immigrant women cope with domestic violence. The research used a route theory approach, and 11 of marriage immigrant women who have ever suffered from domestic violence participated in it. The research question used semi-structured open questions. As a result of paradigm model analysis, "mental and physical devastation" is defined as a core phenomenon, and causative conditions are "wheel of pain" and "helpless victims of violence". Besides, context conditions are "period growth with solitariness", "irrational marriage" and "indifferent reality". "Mental and physical devastation", the core phenomenon act and interact with effect of mediatory conditions; which are "social help", "cultural difference" and "helplessness". Here the action and reaction appear as "adaptation", "resistance", "self-protection" and "self-reinforcement", and the outcomes show up as "maintaining reality", "decision making" and "beginning a new life". "Coping with mental and physical devastation and standing on one's own feet" could be introduced as a core category. Process of coping with domestic violence presents its levels as; shocks ${\rightarrow}$ endurance ${\rightarrow}$ regret ${\rightarrow}$ overcoming. There are three patterns of coping, which are; "preserving realities", "returning", and "groping for the future".

Conflict resolution and political tasks on the usage of beauty care devices by beauty artists (미용업종사자의 미용기기 사용에 대한 분쟁해결과 정책적 과제)

  • Kim, Ju-Ri
    • Journal of Arbitration Studies
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    • v.27 no.2
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    • pp.83-105
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    • 2017
  • In contemporary society interest in and consumption of beauty treatment are increasing, raising interest in health and beauty. However, beauty-related laws are becoming factors of hindrance of beauty development. Currently the Public Health Control Act plays a basic role in the beauty art business in Korea, However the contents are in discord with international laws and its definition is not clear. Therefore it is causing conflicts of different occupations and job associations which are similar to art business. Especially, because neither definitions nor policies on beauty care devices exist in the Public Health Control Act, beauty care devices using in foreign countries cannot be used in Korea due to classification as medical devices. Under this circumstance, therefore, beauty care device uses by beauty artists violate the law. The government has tried to solve these irrational regulations. Recently, the Small and Medium Business Administration announced 'the improvement plan of small business and young founders site regulation for public economy recovery' in a ministerial meeting on December 28, 2016. Regulations on policy preparation for skincare devices were inclusive in this announcement. It is the question whether the regulations will be executed or not. Even though beauty industrial competitiveness was presented in the 18th Presidential Council on National Competitiveness in 2009, it was not practiced. The proposal bills for beauty law improvement have been put forth several times since 2000 including an improvement plan for regulating beauty care devices. However, so far there have been no improvements. The damage on the regulation classifying beauty devices as medical devices is not only restricted to skincare. This develops beauty devices and the beauty industry which imports and exports beauty devices. When beauty devices are exported, complicated procedures are unavoidable and when beauty devices are imported, irrational problems like reregistration procedures and costs occur. The reason why an improvement plan has not gone into practice is the resistance of the dermatologists' association. Dermatologists tend to stand positively against harming public health by saying that beauty devices used by beauty artists cause people to suffer side effects. In contrast, anyone who has a licence to use beauty devices is able to use them in foreign countries. It is not only infringement of one's right as a beauty artist but also people's right to receive beauty care services. With this reason, Korean's current law under which beauty devices are ruled as medical devices should be revised with accordance to domestic surroundings. Therefore in order to advance and globalize the beauty industry, the support and cooperation of the Korean government and relevant associations is needed to legislate and revise the beauty devices laws. The relevant associations abandon regional self-centeredness and cooperate to define ranges, size and management of beauty devices for safe use. If no collaboration exists, an arbitration agency should be established to solve the problem.

Analysis of the Causes of Deformation of Packaging Materials Used for Ready-to-Eat Foods after Microwave Heating (즉석편의 식품용 포장재의 전자레인지 가열에 의한 변형 원인 분석)

  • Yoon, Chan Suk;Hong, Seung In;Cho, Ah Reum;Lee, Hwa Shin;Park, Hyun Woo;Lee, Keun Taik
    • Korean Journal of Food Science and Technology
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    • v.47 no.1
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    • pp.63-69
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    • 2015
  • The aim of this study was to investigate the deformation of packaging materials used for ready-to-eat (RTE) foods after the retort process and microwave heating. From the multilayer films consisting of polyethylene terephthalate (PET), polyamide (PA), and cast polypropylene (CPP) in a stand-up pouch form used for RTE foods, some deformation of the CPP layer, which was in direct contact with the food, was observed after the retort process and microwave heating. The damage was more severely caused by microwave heating than by the retort process. This may be attributed to diverse factors including the non-uniform heating in a microwave oven, the sorption of oil into the packaging film, and the different characteristics of food components such as viscosity, salt and water content. The development of heat-resistant packaging materials and systems suitable for microwave heating of RTE foods is required for the safety of consumers.