• Title/Summary/Keyword: bed protection

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An Analysis of Bed Change Characteristics by Bed Protection Work (바닥보호공 설치에 따른 하상변동 특성 분석)

  • Son, Ah Long;Kim, Byung Hyun;Moon, Bo Ram;Han, Kun Yeun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.4
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    • pp.821-834
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    • 2015
  • This study presents the analysis of flow and bed change characteristics considering bed protection work built on the immediate downstream of weir to protect river bed from scouring. The study area is 37km reach from Hyunpoong station to Masuwon station including Hapcheon- Changryoung multi-function weir in the Nakdong river. CCHE2D model is calibrated and validated for evaluating the flow and bed change characteristics during Typhoon Kompasu in 2010. Three simulation conditions are set up: Case 1 is a natural channel without installation of weir. Case 2 involves an installation of weir in the natural channel. Case 3 involves an installation of weir with bed protection in the natural channel. Flood frequency (50, 100 and 200yr) is applied to each scenario to analyze the effects of bed protection work. While the sediment rate is increased in the downstream of fixed gate and sluice-type gate, river bed scouring rate is increased in the downstream of lift-type gate in Case 2 comparing with the results of Case 1. The river bed scouring is not occurred in the immediate downstream of weir (~30m) due to the effect of bed protection, but larger amount of sediment is occurred in the downstream of weir (60m~) which the bed protection is not installed comparing with the results Case 1. Through the results of simulation considering bed protection work, this study would be helpful to expect bed change and operate the weir as well as manage.

Adhesive Silicone Gel Sheet for Treatment of Nailbed Injury (손톱바닥 치료를 위한 부착형 실리콘 겔 시트의 유용성)

  • Kim, Eui Sik;Hwang, Jae Ha;Kim, Kwang Seog
    • Archives of Plastic Surgery
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    • v.33 no.1
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    • pp.107-112
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    • 2006
  • If autogenous nail is lost in nail bed injuries, alternative effective nail bed protection material is questionable in postoperative follow up period. The conventional modality with autogenous nail coverage have several disadvantages such as drawback of maintenance, higher chance of loss and complex dressing step (eg. ointment apply for humidification and nail fixation using tape or bandage). So, we have studied the usefulness of adhesive silicone gel sheet for alternative nail bed protection material until the end of nail regeneration. From March 2003 to July 2004, we have experienced 215 traumatic nail bed injuries except fingertip loss. Among these patient, we classified two groups, 30 cases with autogenous nail protection(Group I) and 30 cases with adhesive silicone gel sheet protection(Group II). Mean full nail growth time was 3.6 months in group I and 3.8 months in group II. Mean final nail appearance score(0: poor, 4: excellent) was 3.0 in group I and 3.5 in group II. Adhesive silicone gel sheet protection(Group II) was slightly superior to the autogenous nail protection in final appearance, especially sterile matrix laceration. In conclusion, we believe that adhesive silicone gel sheet application is a simple, acceptable, alternative method for protecting nail bed with loss of autogenous nail. It has a number of advantages compared with autogenous nail such as better humidification, controllable hygiene, less pain, less hospitalization, less frequent visit, less chance of loss, avoiding complex dressing step and more even pressure with adhesiveness, flexibility and durability.

Numerical Analysis on the Turbulence Patterns in The Scour Hole at The Downstream of Bed Protection (하상보호공 직하류부 세굴공의 난류양상에 관한 수치해석적 연구)

  • Lee, Jaelyong;Park, Sung Won;Yeom, Seongil;Ahn, Jungkyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.20-26
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    • 2019
  • Where hydraulic structures are to be installed over the entire width of a river or stream, usually a bed protection structure is to be installed. However, a local scour occurs in which the river bed downstream of the river protection system is eroded due to the influence of the upstream flow characteristics. This local scour is dominant in the flow and turbulence characteristics at the boundary of the flow direction and in the material of the bed materials, and may gradually become dangerous over time. Therefore, in this study, we compared the turbulence patterns in the local scour hole at the downstream of the river bed protection with the results of the analysis of the mobile bed experiment, and compared with the application of OpenFoam, a three dimensional numerical analysis model. The distribution of depth-averaged relative turbulence intensities along the flow direction was analyzed. In addition to this result, the stabilization of scour hole was compared with the bed shear stress and Shields parameter, and the results were compared by changing the initial turbulent flow conditions. From the results, it was confirmed that the maximum depth of generation of the three-stage was dominantly developed by the magnitude of depth-averaged relative turbulence intensity rather than the mean flow velocity. This result also suggests that design, construction or gate control are needed to control the depth-averaged relative turbulence intensities in order to reduce or prevent the local scour faults that may occur in the downstream part of the bed protection.

Monitoring of Pyrethroid Resistance Allele Frequency in the Common Bed Bug (Cimex lectularius) in the Republic of Korea

  • Cho, Susie;Kim, Heung-Chul;Chong, Sung-Tae;Klein, Terry A.;Kwon, Deok Ho;Lee, Si Hyeock;Kim, Ju Hyeon
    • Parasites, Hosts and Diseases
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    • v.58 no.1
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    • pp.99-102
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    • 2020
  • Two-point mutations (V419L and L925I) on the voltage-sensitive sodium channel of bed bugs (Cimex lectularius) are known to confer pyrethroid resistance. To determine the status of pyrethroid resistance in bed bugs in Korea, resistance allele frequencies of bed bug strains collected from several US military installations in Korea and Mokpo, Jeollanamdo, from 2009-2019 were monitored using a quantitative sequencing. Most bed bugs were determined to have both of the point mutations except a few specimens, collected in 2009, 2012 and 2014, having only a single point mutation (L925I). No susceptible allele was observed in any of the bed bugs examined, suggesting that pyrethroid resistance in bed bug populations in Korea has reached a serious level. Large scale monitoring is required to increase our knowledge on the distribution and prevalence of pyrethroid resistance in bed bug populations in Korea. Based on present study, it is urgent to restrict the use of pyrethroids and to introduce effective alternative insecticides. A nation-wide monitoring program to determine the pyrethroid resistance level in bed bugs and to select alternative insecticides should be implemented.

Study on Fire safety test method for the bed mattress (침대 매트리스 화재안전 평가에 대한 국내외 적용 현황)

  • Park, Kye-Won;Jeong, Jae-Gun
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2012.04a
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    • pp.325-328
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    • 2012
  • This paper intends to introduce foreign/ domestic situation on fire safety assessment of bed mattress. America continent countries and ISO recently adapt real scale test method, other coutries including Korea have been using small scale test method such as IMO FTP code's bed component fire test.

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Description on assessment system of bed mattress's fire safety in real scale (침대 매트리스 실규모 화재안전 평가시스템 기술)

  • Park, Kye-Won;Jeong, Jae-Gun
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2012.04a
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    • pp.329-332
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    • 2012
  • This study focuses on the establishment of bed mattress fire test in real scale where it explains the burner heat supply, test procedure and test report in detail. Especially burner system is dealt in importance for bed mattress test in real scale due to simulating in bedding component by burner heat out-put.

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Study on Fire Safety Test Method for the Bed Mattress (침대 매트리스에 대한 화재 안전성 평가 연구)

  • Park, Kye-Won;Jeong, Jae-Gun
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2011.11a
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    • pp.197-200
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    • 2011
  • This study aims to inform of current situation related to fire safety performance regulation on bed mattress in domestic and foreign countries, and even to make a slight analysis report on heat release rate of bed mattress based on preliminary KICT study which has comparison data together with several items inside house.

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An Experimental Study for Estimation of Bed Protection Length (보 하류부 하상보호공 길이산정을 위한 실험연구)

  • Jung, Jae-Kwang
    • Journal of Wetlands Research
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    • v.13 no.3
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    • pp.677-686
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    • 2011
  • This study proposes a formula to calculate length of river bed protection through experimental research and an experimental plant has been installed to investigate the parameters which influence the length of scouring in the river after overflowing the weir. Through hydraulic experiments, the critical velocity, difference of water level between upstream and downstream and height of weir have been selected as independent variables. And new formula to calculate a length of river bed protection is suggested as the result of this study in the consideration of complex weir that consists of movable and fixed weir. The new formula is verified through additional experiments. Results of this study can be used for weir structures' construction and maintenance plans.