• Title/Summary/Keyword: physical damage

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Ultrasonic Properties on Building Stones, Characteristics of Structural Deformation and Conservation States of the Sanctuary in Wat Phou Temple of Champasak, Lao PDR (라오스 밧푸 주사원의 보존현황과 석재의 초음파 물성 및 구조적 변형특성)

  • Lee, Chan Hee;Shin, Hyo Cheol;Han, Doo Roo
    • Journal of Conservation Science
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    • v.33 no.6
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    • pp.399-416
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    • 2017
  • The 'Wat Phou and Associated Ancient Settlements within the Champasak Cultural Landscape' of Laos was designated as a UNESCO World Cultural Heritage in 2001. The uppermost structure of the Sanctuary in Wat Phou has been destroyed and being variably damaged, maintenance is required through scientific and systematic diagnosis. The Sanctuary of Wat Phou was constructed mainly using sandstones and bricks. There are physical damages including fracture, break out, exfoliation and interval as well as biological damages by lichen, mosses and weeds. According to the ultrasonic velocity measurement and property evaluation of the sandstones of the Sanctuary in Wat Phou, weathering index of the eastern side sandstones is 0.10 to 0.74 (mean 0.36), showing MW grade. Southern and northern side sandstones have relatively higher properties with average weathering indices of 0.30 and 0.32. The results of slope analysis of the Sanctuary, indicated that the 4th spot in the southern side has the largest slope of $5^{\circ}W$, seemingly due to the unstable ground around the Sanctuary. Based on the relative level measurement and past drawings, the Sanctuary is verified to have been located on ground with a certain slope rather than flatland. The ground of the southern side is inclined $1.51^{\circ}$ more than that of the northern side, which will affect the structural stability of the temple. The interval width of the selected southern spot is the largest with an average width of 159.5 mm, and the largest width is 328.3 mm at the top, since the width increases above rather than below, seemingly due to the unequal subsidence of the ground. Constant maintenance for conservation is required for the structural stability of the Sanctuary in Wat Phou, which was partly collapsed and has also suffered physical damage.

Development of Porcine Pericardial Heterograft for Clinical Application (Tensile Strength-thickness) (돼지의 심낭을 이용한 이종이식 보철편의 개발 (장력-두께간의 구조적 특성))

  • Kim, Kwan-Chang;Lee, Cheul;Choi, Chang-Hue;Lee, Chang-Ha;Oh, Sam-Sae;Park, Seong-Sik;Kim, Kyung-Hwan;Kim, Woong-Han;Kim, Yong-Jin
    • Journal of Chest Surgery
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    • v.41 no.2
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    • pp.170-176
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    • 2008
  • Background: Bioprosthetic devices for treating cardiovascular diseases and defects may provide alternatives to autologous and homograft tissue. We evaluated the mechanical and physical conditions of a porcine pericardial bioprosthesis treated with Glutaraldehyde (GA), Ethanol, or Sodium dodecylsulfate (SDS) before implantation. Material and Method: 1) Thirty square-shaped pieces of porcine pericardium were fixed in 0.625%, 1.5% or 3% GA solution. 2) The tensile strength and thickness of these and other bioprosthesis, including fresh porcine pericardium, fresh human pericardium, and commercially produced heterografts, were measured. 3) The tensile strength and thickness of the six treated groups (GA-Ethanol, Ethanol-GA, SDS only, SDS-GA, Ethanol-SDS-GA and SDS-Ethanol-GA) were measured. Result: 1) Porcine pericardium fixed in 0.625% GA the thinnest and had the lowest tensile strength, with thickness and tensile strength increasing with the concentration of GA solution. The relationship between tensile strength and thickness of porcine pericardium increased at thicknesses greater than 0.1mm (correlation-coefficient 0.514, 0<0.001). 2) There were no differences in tensile strength or thickness between commercially-produced heterografts. 3) Treatment of GA, ethanol, or SDS minimally influenced thickness and tensile strength of porcine pericardium, except for SDS alone. Conclusion: Porcine pericardial bioprosthesis greater than 0.1 mm thick provide better handling and advantageous tensile strength. GA fixation did not cause physical or mechanical damage during anticalcification or decellularization treatment, but combining SDS-ethanol pre-treatment and GA fixation provided the best tensile strength and thickness.

Breaking Physical Dormancy with Sulfuric Acid in Seeds of Lespedeza tomentosa (Thunb.) Siebold ex Maxim (황산처리를 이용한 개싸리 종자의 물리적 휴면 타파)

  • Rhie, Yong Ha;Choi, Han;Lee, Su Gwang;Lee, Jeong Ho;Lee, Ki Cheol
    • Korean Journal of Plant Resources
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    • v.29 no.1
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    • pp.136-142
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    • 2016
  • Lespedeza species are mainly used for wildlife food and cover and for erosion control. The germination of these species can be enhanced after a fire occurrence in forest, which is known as fire-activated seeds to germinate. While the heat treatment could break seed dormancy of Lespedeza, its germination rate was quite low. We investigated that chemical scarification could promote germination of L. tomentosa. Seeds were soaked in 100% sulfuric acid (H2SO4) for 0, 1, 3, 6, 12, 24, 48, 96, 192, and 384 min, and then washed in distilled water for 24 h. Very few seeds were germinated in control (H2SO4 for 0 min). More than 90% of seeds were germinated in H2SO4 for 24, 48, and 92 min. However, some damage was observed in roots and cotyledons of seedling dipped in H2SO4 for a long time. To search the optimal soaking time in H2SO4 without defects, seeds scarified in H2SO4 for 30, 60, 90, 120, 150, 180, and 300 min were sown the commercial soil medium. Seeds treated with H2SO4 for 90 min and 150 min emerged by about 92% and 84%, respectively. Therefore, H2SO4 treatment could break the seed dormancy of Lespedeza species, and especially in case of L. tomentosa the optimal treatment time in sulfuric acid was one to two hours. Germination of L. tomentosa began promptly following the scarification and was completed within about one month, indicating that seeds has no physiological dormancy, just has physical dormancy.

Development of a Thermoplastic Oral Compensator for Improving Dose Uniformity in Radiation Therapy for Head and Neck Cancer (두경부암 방사선치료 시 선량 균일도 향상을 위한 Thermoplastic 구강 보상체의 개발)

  • Choi, Joon-Yong;Won, Young-Jin;Park, Ji-Yeon;Kim, Jong-Won;Moon, Bong-Ki;Yoon, Hyong-Geun;Moon, Soo-Ho;Jeon, Jong-Byeong;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.23 no.4
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    • pp.269-278
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    • 2012
  • Aquaplast Thermoplastic (AT) is a tissue-equivalent oral compensator that has been developed to improve dose uniformity at the common boundary and around the treated area during radiotherapy in patients with head and neck cancer. In order to assess the usefulness of AT, the degree of improvement in dose distribution and physical properties were compared to those of oral compensators made using paraffin, alginate, and putty, which are materials conventionally used in dental imprinting. To assess the physical properties, strength evaluations (compression and drop evaluations) and natural deformation evaluations (volume change over time) were performed; a Gafchromic EBT2 film and a glass dosimeter inserted into a developed phantom for dose verification were used to measure the common boundary dose and the beam profile to assess the dose delivery. When the natural deformation of the oral compensators was assessed over a two-month period, alginate exhibited a maximum of 80% change in volume from moisture evaporation, while the remaining tissue-equivalent properties, including those of AT, showed a change in volume that was less than 3%. In a free-fall test at a height of 1.5 m (repeated 5 times as a strength evaluation), paraffin was easily damaged by the impact, but AT exhibited no damage from the fall. In compressive strength testing, AT was not destroyed even at 8 times the force needed for paraffin. In dose verification using a glass dosimeter, the results showed that in a single test, the tissue-equivalent (about 80 Hounsfield Units [HU]) AT delivered about 4.9% lower surface dose in terms of delivery of an output coefficient (monitor unit), which was 4% lower than putty and exhibited a value of about 1,000 HU or higher during a dose delivery of the same formulation. In addition, when the incident direction of the beam was used as a reference, the uniformity of the dose, as assessed from the beam profile at the boundary after passing through the oral compensators, was 11.41, 3.98, and 4.30 for air, AT, and putty, respectively. The AT oral compensator had a higher strength and lower probability of material transformation than the oral compensators conventionally used as a tissue-equivalent material, and a uniform dose distribution was successfully formed at the boundary and surrounding area including the mouth. It was also possible to deliver a uniformly formulated dose and reduce the skin dose delivery.

The Relationship between Climate and Food Incidents in Korea (식품안전 사건 사고와 기후요소와의 관련성)

  • Lee, Jong-Hwa;Kim, Young-Soo;Baek, Hee-Jung;Chung, Myung-Sub
    • Journal of Climate Change Research
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    • v.2 no.4
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    • pp.297-307
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    • 2011
  • This study investigates relation of food safety incidents with climate. Therefore food safety incidents and climate data during 1999 to 2009 have been analyzed. In situ observations of monthly mean temperature, maximum temperature, minimum temperature, precipitation, and relative humidity in 60 observation stations of Korean Meteorological Administration (KMA) have been used in this study. Food safety incidents data have been constructed by searching media reports following Park's method (2009) during the same period. According to the Park's method, 729 events were collected. To analyze its relations, food safety incidents data have been classified into chemical, biological, and physical hazards. Pearson product-moment correlation coefficients have been applied to analyze the relations. The correlation of food safety incidents has negative one with precipitation (-0.48), and positive one with minimum temperature(0.45). Precipitation has been correlated with biological and physical hazards more than chemical hazard. Temperatures (mean temperature, maximum temperature, and minimum temperature) have been correlated closely with chemical hazard than others. Food safety incidents data has been interblended with human behavior factor through decision-making processes in food manufacturing, processing, and consumption phases of "farm-totable" food processing. Act in the preventing damage will be obvious if the hazard were apparent. Therefore abnormal condition could be more dangerous than that of apparent extreme events because apparent events or extreme events become one of alarm over hazards. Therefore, human behavior should be considered as one of the important factors for analysis of food safety incidents. The result of this study can be used as a better case study for food safety researches related to climate change.

Contaminant Mechanism and Management of Tracksite of Pterosaurs, Birds, and Dinosaurs in Chungmugong-dong, Jinju, Korea (천연기념물 진주 충무공동 익룡·새·공룡발자국 화석산지의 오염물 형성 메커니즘과 관리방안)

  • Myoungju Choie;Sangho Won;Tea Jong Lee;Seong-Joo Lee;Dal-Yong Kong;Myeong Seong Lee
    • Economic and Environmental Geology
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    • v.56 no.6
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    • pp.715-728
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    • 2023
  • Tracksite of pterosaurs, birds, and dinosaurs in Chungmugong-dong in Jinju was designated as a natural monument in 2011 and is known as the world's largest in terms of the number and density of pterosaur footprints. This site has been managed by installing protection buildings to conserve in 2018. About 17% of the footprints of pterosaur, theropod, and ornithopod in this site under management in the 2nd protection building are of great academic value, but observation of footprints has difficulties due to continuous physical and chemical damage. In particular, the accumulation of milk-white contaminants is formed by the gypsum and air pollutant complex. Gypsum remains evaporated with a plate or columnar shape in the process of water circulation around the 2nd protection building, and the dust is from through the inflow of the gallery windows. The aqueous solution of gypsum, consisting of calcium from the lower bed and sulfur from grass growth, is catchmented into the groundwater from the area behind the protection building. Pollen and a few minerals other constituents of contaminants, go through the gallery window, which makes it difficult to expel dust. To conserve the fossil-bearing beds from two contaminants of different origins, controlling the water and atmospheric circulation of the 2nd protection building and removing the contaminants continuously is necessary. When cleaning contaminants, the steam cleaning method is sufficiently effective for powder-shaped milk-white contaminants. The fossil-bearing bed consists of dark gray shale with high laser absorption power; the laser cleaning method accompanies physical loss to fossils and sedimentary structures; therefore, avoiding it as much as possible is desirable.

Development of Porcine Pericardial Heterograft for Clinical Application (Microscopic Analysis of Various Fixation Methods) (돼지의 심낭, 판막을 이용한 이종이식 보철편의 개발(고정 방법에 따른 조직학적 분석))

  • Kim, Kwan-Chang;Choi, Chang-Hyu;Lee, Chang-Ha;Lee, Chul;Oh, Sam-Sae;Park, Seong-Sik;Kim, Woong-Han;Kim, Kyung-Hwan;Kim, Yong-Jiin
    • Journal of Chest Surgery
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    • v.41 no.3
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    • pp.295-304
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    • 2008
  • Background: Various experimental trials for the development of bioprosthetic devices are actively underway, secondary to the limited supply of autologous and homograft tissue to treat cardiac diseases. In this study, porcine bioprostheses that were treated with glutaraldehyde (GA), ethanol, or sodium dodecylsulfate (SDS) were examined with light microscopy and transmission electron microscopy for mechanical and physical imperfections before implantation, Material and Method: 1) Porcine pericardium, aortic valve, and pulmonary valve were examined using light microscopy and JEM-100CX II transmission electron microscopy, then compared with human pericardium and commercially produced heterografts. 2) Sections from six treated groups (GA-Ethanol, Ethanol-GA, SDS only, SDS-GA, Ethanol-SDS-GA and SDS-Ethanol-GA) were observed using the same methods. Result: 1) Porcine pericardium was composed of a serosal layer, fibrosa, and epicardial connective tissue. Treatment with GA, ethanol, or SDS had little influence on the collagen skeleton of porcine pericardium, except in the case of SDS pre-treatment. There was no alteration in the collagen skeleton of the porcine pericardium compared to commercially produced heterografts. 2) Porcine aortic valve was composed of lamina fibrosa, lamina spongiosa, and lamina ventricularis. Treatment with GA, ethanol, or SDS had little influence on these three layers and the collagen skeleton of porcine aortic valve, except in the case of SDS pre-treatment. There were no alterations in the three layers or the collagen. skeleton of porcine aortic valve compared to commercially produced heterografts. Conclusion: There was little physical and mechanical damage incurred in porcine bioprosthesis structures during various glutaraldehyde fixation processes combined with anti-calcification or decellularization treatments. However, SDS treatment preceding GA fixation changed the collagen fibers into a slightly condensed form, which degraded during transmission electron micrograph. The optimal methods and conditions for sodium dodecylsulfate (SDS) treatment need to be modified.

Liability of the Compensation for Damage Caused by the International Passenger's Carrier by Air in Montreal Convention (몬트리올조약에 있어 국제항공여객운송인의 손해배상책임)

  • Kim, Doo-Hwan
    • The Korean Journal of Air & Space Law and Policy
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    • v.18
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    • pp.9-39
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    • 2003
  • The rule of the Warsaw Convention of 1929 are well known and still being all over the world. The Warsaw Convention is undoubtedly the most widely accepted private international air law treaty with some 140 countries. In the international legal system for air transportation, the Warsaw Convention has played a major role for more than half century, and has been revised many times in consideration of the rapid developments of air high technology, changes of social and economic circumstances, need for the protection of passengers. Some amendments became effective, but others are still not effective. As a result, the whole international legal system for air transportation is at past so complicated and tangled. However, the 'Warsaw system' consists of the Warsaw Convention of 1929 the Guadalajara Convention of 1961, a supplementary convention, and the following six protocols: (1) the Hague Protocol of 1955, (2) the Guatemala Protocol of 1971, (3) the Montreal Additional Protocols, No.1, (4) the Montreal Additional Protocol No.2, (5) the Montreal Additional Protocol No.3, and (6) the Montreal Additional Protocol No.4. of 1975. As a fundamental principle of the air carrier's liability in the international convention and protocols, for instance in the Warsaw Convention and the Hague Protocol, the principle of limited liability and a presumed fault system has been adopted. Subsequently, the Montreal Inter-carrier Agreement of 1966, the Guatemala City Protocol, the Montreal Additional Protocol No.3, and the Montreal Additional Protocol No. 4 of 1975 maintained the limited liability, but substituted the presumed liability system by an absolute liability, that is, strict liability system. The Warsaw System, which sets relatively low compensation limits for victims of aircraft accidents and regulates the limited liability for death and injury of air passengers, had become increasingly outdated. Japanese Airlines and Inter-carrier Agreement of International Air Transport Association in 1995 has been adopted the unlimited liability of air carrier in international flight. The IATA Inter-Carrier Agreement, in which airlines in international air transportation agree to waive the limit of damages, was long and hard in coming, but it was remarkable achievement given the political and economic realities of the world. IATA deserves enormous credit for bringing it about. The Warsaw System is controversial and questionable. In order to find rational solution to disputes between nations which adopted differing liability systems in international air transportation, we need to reform the liability of air carriers the 'Warsaw system' and fundamentally, to unify the liability system among the nations. The International Civil Aviation Organization(ICAO) will therefore reinforce its efforts to further promote a legal environment that adequately reflects the public interest and the needs of the parties involved. The ICAO Study Group met in April, 1998, together with the Drafting Committee. The time between the "Special Group on the Modernization and Consolidation of the 'Warsaw system'(SGMW)" and the Diplomatic Conference must be actively utilized to arrange for profound studies of the outstanding issues and for wide international consultations with a view to narrowing the scope of differences and preparing for a global international consensus. From 11 to 28 May 1999 the ICAO Headquarters at Montreal hosted a Diplomatic Conference convened to consider, with a view to adoption, a draft Convention intended to modernize and to integrate replace the instruments of the Warsaw system. The Council of ICAO convened this Conference under the Procedure for the Adoption of International Conventions. Some 525 participants from 121 Contracting States of ICAO attended, one non-contracting State, 11 observer delegations from international organizations, a total of 544 registered participants took part in the historic three-week conference which began on 10 May. The Conference was a success since it adopted a new Convention for the Unification of Certain Rules for International Carriage by Air. The 1999 Montreal Convention, created and signed by representatives of 52 countries at an international conference convened by ICAO at Montreal on May 28, 1999, came into effect on November 4, 2003. Representatives of 30 countries have now formally ratified the Convention under their respective national procedures and ratification of the United States, which was the 30th country to ratify, took place on September 5, 2003. Under Article 53.6 of the Montreal Convention, it enters into force on the 60th day following the deposit of the 30th instrument of ratification or acceptation. The United States' ratification was deposited with ICAO on September 5, 2003. The ICAO have succeeded in modernizing and consolidating a 70-year old system of international instruments of private international law into one legal instrument that will provide, for years to come, an adequate level of compensation for those involved in international aircraft accidents. An international diplomatic conference on air law by ICAO of 1999 succeeded in adopting a new regime for air carrier liability, replacing the Warsaw Convention and five other related legal instruments with a single convention that provided for unlimited liability in relation to passengers. Victims of international air accidents and their families will be better protected and compensated under the new Montreal Convention, which modernizes and consolidates a seventy-five year old system of international instruments of private international law into one legal instrument. A major feature of the new legal instrument is the concept of unlimited liability. Whereas the Warsaw Convention set a limit of 125,000 Gold Francs (approximately US$ 8,300) in case of death or injury to passengers, the Montreal Convention introduces a two-tier system. The first tier includes strict liability up to l00,000 Special Drawing Rights (SDR: approximately US$ 135,000), irrespective of a carrier's fault. The second tier is based on presumption of fault of a carrier and has no limit of liability. The 1999 Montreal Convention also includes the following main elements; 1. In cases of aircraft accidents, air carriers are called upon to provide advance payments, without delay, to assist entitled persons in meeting immediate economic needs; the amount of this initial payment will be subject to national law and will be deductable from the final settlement; 2. Air carriers must submit proof of insurance, thereby ensuring the availability of financial resources in cases of automatic payments or litigation; 3. The legal action for damages resulting from the death or injury of a passenger may be filed in the country where, at the time of the accident, the passenger had his or her principal and permanent residence, subject to certain conditions. The new Montreal Convention of 1999 included the 5th jurisdiction - the place of residence of the claimant. The acceptance of the 5th jurisdiction is a diplomatic victory for the US and it can be realistically expected that claimants' lawyers will use every opportunity to file the claim in the US jurisdiction - it brings advantages in the liberal system of discovery, much wider scope of compensable non-economic damages than anywhere else in the world and the jury system prone to very generous awards. 4. The facilitation in the recovery of damages without the need for lengthy litigation, and simplification and modernization of documentation related to passengers. In developing this new Montreal Convention, we were able to reach a delicate balance between the needs and interests of all partners in international civil aviation, States, the travelling public, air carriers and the transport industry. Unlike the Warsaw Convention, the threshold of l00,000 SDR specified by the Montreal Convention, as well as remaining liability limits in relation to air passengers and delay, are subject to periodic review and may be revised once every five years. The primary aim of unification of private law as well as the new Montreal Convention is not only to remove or to minimize the conflict of laws but also to avoid conflict of jurisdictions. In order to find a rational solution to disputes between nations which have adopted differing liability systems in international air transport, we need fundamentally to reform their countries's domestic air law based on the new Montreal Convention. It is a desirable and necessary for us to ratify rapidly the new Montreal Convention by the contracting states of lCAO including the Republic of Korea. According to the Korean and Japanese ideas, airlines should not only pay compensation to passengers immediately after the accident, but also the so-called 'condolence' money to the next of kin. Condolence money is a gift to help a dead person's spirit in the hereafter : it is given on account of the grief and sorrow suffered by the next of kin, and it has risen considerably over the years. The total amount of the Korean and Japanese claims in the case of death is calculated on the basis of the loss of earned income, funeral expenses and material demage (baggage etc.), plus condolence money. The economic and social change will be occurred continuously after conclusion of the new Montreal Convention. In addition, the real value of life and human right will be enhanced substantially. The amount of compensation for damage caused by aircraft accident has increased in dollar amount as well as in volume. All air carrier's liability should extend to loss of expectation of leisure activities, as well as to damage to property, and mental and physical injuries. When victims are not satisfied with the amount of the compensation for damage caused by aircraft accident for which an airline corporation is liable under the current liability system. I also would like to propose my opinion that it is reasonable and necessary for us to interpret broadly the meaning of the bodily injury on Article 17 of the new Montreal Convention so as to be included the mental injury and condolence. Furthermore, Korea and Japan has not existed the Air Transport Act regulated the civil liability of air carrier such as Air Transport Act (Luftverkehrsgestz) in Germany. It is necessary for us to enact "the Korean Air Transport Contract Act (provisional title)" in order to regulate the civil liability of air carrier including the protection of the victims and injured persons caused by aircraft accident.

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Division of Soil Properties in Reclaimed Land of the Mangyeong and Dongjin River Basin and Their Agricultural Engineering Management (만경강과 동진강 유역 간척농경지 토양특성 구분과 농공학적 관리 대책)

  • Hwang, Seon-Woong;Kang, Jong-Gook;Lee, Kyung-Do;Lee, Kyung-Bo;Park, Ki-Hun;Chung, Doug-Young
    • Korean Journal of Soil Science and Fertilizer
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    • v.45 no.3
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    • pp.444-450
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    • 2012
  • The physical and chemical properties of soil in the Mangyeong and Dongjin river basin had been investigated in order to establish the most optimum soil improvement plan on the reclaimed land. The total soil area by reclamation in Saemangeum basin is 113,971 ha. The classification by the distribution of soil series and soil texture is as following. 13 soil series including Chonnam, Buyong and Chonbuk series are period-unknown areas. Regarding the soil texture, they are fine silty ~ clayey very fine. From 1920s to 1960s, Mangyeong, Gwanghwal and Chonbuk series had coarse silty textured soil. After the 1970s, Mangyeong, Gwanghwal, Munpo, Yeompo, Poseung, Gapo and Hasa series have more sandy soil ~ moderately coarse loamy textured soil. Regarding the chemical properties, the concentrations of EC, Exch. $K^+$, $Mg^{2+}$, $Na^+$ and pH are high regardless of the time of reclamation. On the other hand, organic matter (OM) of top soil were 3.3~16.1 g $kg^{-1}$. The organic matter contents were very low though the soil had been farmed for a long time. Furthermore, the deep soil had almost no organic matter with 5.6~1.1 g $kg^{-1}$. The reason is believed that there had not been any movement of OM and clay because pressure or induced pans had been formed by large agricultural machineries and poor vertical drain. Regarding the forming of illuvial horizon (B layer) which tells the development extent of soil, only in the Hwapo reclaimed area where rice had been cultivated for past 90 years, Fe and Mn from top soil are deposited at underground 20~30 cm with 7~8 cm thickness by the movement of clay. It is believed that it had been possible because the earthiness is silty clay loam soil with relatively high content of clay. The soils are soil with concern of damage from sea water, soil on flimsy ground and sandy soil. Therefore, soil improvement for stable crop production can be expected; if the water table would be lowered by subsurface drainage, the water permeability would be enhanced by gypsum and organic matter, and the sandy soil would be replaced by red soil with high content of clay.

Evaluation on the adsorption and desorption capabilities of filter media applied to the nonpoint source pollutant management facilities (비점오염 저감시설에 적용되는 여재의 흡착 및 탈착 능력 평가)

  • Moon, Soyeon;Hong, Jungsun;Choi, Jiyeon;Yu, Gigyung;Kim, Lee Hyung
    • Journal of Wetlands Research
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    • v.17 no.3
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    • pp.228-236
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    • 2015
  • Urbanization causes many environmental, hydrological and ecological problems such as distortion of the natural water circulation system, increase in nonpoint source pollutants in stormwater runoff, degradation of surface water quality, and damage to the ecosystem. Due to the increase in impervious surface by urbanization, developed countries apply low impact development (LID) techniques as important alternatives to reduce the impacts of urbanization. In Korea, LID techniques were employed since 2012 in order to manage nonpoint source pollutants. LID technology is a technique for removing pollutants using a variety of physical, chemical and biological mechanisms in plants, microorganisms and filter media with the reduced effluence of stormwater runoff by mimicking natural water circulation system. These LID facilities are used in a variety of filter media, but an assessment has not been carried out for the comprehensive comparison evaluation of adsorption and desorption characteristics for the pollutant removal capacity. Therefore, this study was conducted to analyze the adsorption and desorption characteristics of various filter media used in the LID facilities such as sand, gravel, bioceramic, wood chips and bottom ash etc. in reducing heavy metals(Pb, Cu). In this study, the adsorption affinity for Pb in all filter media was higher than Cu. Pseudo second order equation and Langmuir-3 isotherm are more applicable in the adsorption kinetic model and adsorption isotherm model, respectively. As a result of the desorption experiment, the filter media does not exceed KSLT which is the hazardous substance leaching limit, showing the capability of the filter media in LID. The bioceramic and woodchip as filter medias were evaluated and exhibited excellent adsorption capacity for Pb.