• Title, Summary, Keyword: temporary pool

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Metacyclops woni n. sp., a New Cyclopoid Species (Copepoda: Cyclopoida: Cyclopidae) from Cambodia

  • Lee, Jimin;Chang, Cheon Young
    • Animal Systematics, Evolution and Diversity
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    • v.31 no.4
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    • pp.247-256
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    • 2015
  • A new cyclopoid species belonging to the genus Metacyclops Kiefer, 1927 is described, based upon the specimens from a temporary pool in a forest of Mt. Phnom Domnak Dambouk, situated in the southwestern part of Cambodia. Metacyclops woni sp. nov. is characterized by its quite short caudal rami, about 2.5 times longer than wide, with a spinule row on anterior quarter of lateral margin. This new species belongs to the species group with the spine formula 3,4,4,3 of swimming legs 1-4. Among the members of the species group with the combination of characters of 11-segmented antennule and a single apical spine on the second endopodal segment of leg 4, it most resembles M. deserticus Mercado-Salas and Suárez-Morales, 2013 from Mexico in carrying an outermost caudal seta slightly longer than the innermost caudal seta and an apical spine on the second endopodal segment of leg 4 slightly shorter than the segment. However, it differs clearly from the present new species by much longer caudal rami with lateral caudal seta at nearly halfway of lateral margin of the ramus and smooth posterior margin of intercoxal sclerites of legs 1-4. This is the first record of the genus Metacyclops from Cambodia and the fourth one from Southeast Asia.

A Study on the Efficiency Improvement of Existing Pool-and-Weir Type Fishway in Namgang Weir (남강수중보의 기존 전면월류형 계단식 어도의 효율성 개선에 관한 연구)

  • Lee, Hyeong-Rae;Kim, Ki Heung;Park, Ho Chul
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.17 no.2
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    • pp.61-71
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    • 2014
  • A river fishway is a hydraulic structure enabling fish to overcome stream obstructions such as dams and weirs. The main aim of this paper is to investigate the collectibility of upstream-migrating fishes and hydraulic problems in pool-and-weir type fishway which has been established for upstream-migration at Namgang weir in the downstream of Namgang dam, and to grope for improvement measures which pool-and-weir type fishway can be switched to pool-and-partial weir type fishway through hydraulic field experiment. Exsisting fishway had problems which upstream-migrating fishes can not take a rest due to the seiche and vortex phenomena in pools and migrate to upstream because of height difference in entrance pool. In order to prevent hydraulically the seiche and vortex phenomena and establish rest area for fishes in each pool, we carried out hydraulic field experiments. In the fishway, it was to improve pool-and-weir into pool-and-partil weir, to decrease the height difference in entrance pool, and to reduce oriffice velocity of each pool. Also, we investigated fishes collectibility of after improving fishway for 6 days in September 2013. To resolve chronic problems(seiche-vortex phenomena and rest area for fishes), as weirs were remodeled into partial weir only which central part of weirs was part of non-overflow weir, we confirmed results that pool-and-weir type fishway could be switched to efficient pool-and-partial weir type fishway with relatively simple construction and low cost. Type-B which has the closed oriffices and the parts of non-overflow has the ideal conditions, but this conditions are limited to fishway of Namgang weir used in this study. Representative Ice-habor type fishway is pool-and-partial weir type fishway which has together parts of overflow and oriffices, and has excellent ability of upstream-migration. To switch from pool-and-weir type fishway to pool-and-partial weir type fishway, the size of oriffice has to be regulated by the discharge of fishway and the dimension on parts of non-overflow and overflow in weirs. Entrance pool is important facility which upstream-migrating fishes have to not only be collect but also charge with energy. In this study, entrance-pool is temporary and roughly-built, but fishes gather together more than the case of no entrance-pool. In the case of fishway which was protruded to downstream, as entrance of fishway turns toward or parallels to weir, the collectibility of fishway was excellent by attraction water.

The Conceptual Design of Primary Cooling System for an Advanced Research Reactor (수출전략형 연구로의 1차 냉각계통 개념설계)

  • Park, Yong-Chul;Kim, Kyung-Ryun
    • 유체기계공업학회:학술대회논문집
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    • pp.503-508
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    • 2005
  • An advanced Research Reactor (ARR) consists of an open-tank-type reactor assembly within a light water pool and generates thermal power of 20 MW. The thermal power is including a fission heat in the core, a fuel generated heat temporary stored in the pool, a circulating pumps generated heat and a neutron reflecting heat in the reflector vessel of the reactor. In order to remove the heat load, the primary cooling system will be installed. In this study, the conceptual design of the primary cooling system has been carried out using a design methodology of HANARO within a permissible range of safety. As results, it has been established that the conceptual design of the primary cooling system including design requirements, performance requirements, design restrictions, system descriptions and system operation to maintain the system functions.

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Distribution and Habitat Characteristics of Tadpole Shrimp (Crustacea: Notostraca; Triops longicaudatus (LeConte)) in Korea (한국산 긴꼬리투구새우 (Crustacea: Notostraca; Triops longicaudatus (LeConte))의 분포 및 서식지 특성)

  • Kwon, Soon-Jik;Jun, Yung-Chul;Park, Jae-Heung;Won, Doo-Hee;Seo, Eul-Won;Lee, Jong-Eun
    • Korean Journal of Ecology and Environment
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    • v.43 no.1
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    • pp.142-149
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    • 2010
  • Tadpole shrimps are aquatic crustaceans adapted to temporary water pool. Since they have been recorded as the living fossil, there are a number of reports on their past and present distribution as well as their morphology and reproduction in foreign countries. However, there are few studies of biology and ecology of tadpole shrimps despite registration as an endangered species by Ministry of Environment, in Korea. This study was carried out to examine the distribution and habitat characteristics of tadpole shrimps (Triops longicaudatus) collected from May 2006 to July 2008 in Korea. Tadpole shrimps were found from the paddy fields and ephemeral pools at 21 countries in South Korea. They appeared between May and July and survived for 30 days, and temperatrue range was $10.7^{\circ}C$ to $33.5^{\circ}C$. The average turbidity of experimental paddy fields was 176.8 (${\pm}239.3$) NTU, and controlled field was 28.9 (${\pm}26.7$) NTU. The life pattern of tadpole shrimps is adapted to a temporary water pool and unstable environmental conditions, and also there was great effect of agricultural activity on the development and growth of tadpole shrimps.

Modelling Analysis of Climate and Soil Depth Effects on Pine Tree Dieback in Korea Using BIOME-BGC (BIOME-BGC 모형을 이용한 국내 소나무 고사의 기후 및 토심 영향 분석)

  • Kang, Sinkyu;Lim, Jong-Hwan;Kim, Eun-Sook;Cho, Nanghyun
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.18 no.4
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    • pp.242-252
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    • 2016
  • A process-based ecosystem model, BIOME-BGC, was applied to simulate seasonal and inter-annual dynamics of carbon and water processes for potential evergreen needleleaf forest (ENF) biome in Korea. Two simulation sites, Milyang and Unljin, were selected to reflect warm-and-dry and cool-and-wet climate regimes, where massive diebacks of pines including Pinus densiflora, P. koraiensis and P thunbergii, were observed in 2009 and 2014, respectively. Standard Precipitation Index (SPI) showed periodic drought occurrence at every 5 years or so for both sites. Since mid-2000s, droughts occurred with hotter climate condition. Among many model variables, Cpool (i.e., a temporary carbon pool reserving photosynthetic compounds before allocations for new tissue production) was identified as a useful proxy variable of tree carbon starvation caused by reduction of gross primary production (GPP) and/or increase of maintenance respiration (Rm). Temporal Cpool variation agreed well with timings of pine tree diebacks for both sites. Though water stress was important, winter- and spring-time warmer temperature also played critical roles in reduction of Cpool, especially for the cool-and-wet Uljin. Shallow soil depth intensified the drought effect, which was, however, marginal for soil depth shallower than 0.5 m. Our modeling analysis implicates seasonal drought and warmer climate can intensify vulnerability of ENF dieback in Korea, especially for shallower soils, in which multi-year continued stress is of concern more than short-term episodic stress.

Extracorporeal Life Support in Organ Transplant Donors

  • Chang, Wonho
    • The Korean Journal of Thoracic and Cardiovascular Surgery
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    • v.51 no.5
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    • pp.328-332
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    • 2018
  • Background: Extracorporeal life support (ECLS) can be applied in brain-dead donors for organ perfusion before donation, thereby expanding the donor pool. The aim of this study was to examine the benefits and early clinical outcomes of ECLS for organ preservation. Methods: Between June 2012 and April 2017, 9 patients received ECLS with therapeutic intent or for organ preservation. The following data were collected: demographics, purpose and duration of ECLS, cause of death, dose of vasoactive drugs, and need for temporary dialysis before organ retrieval. The early clinical outcomes of recipients were studied, as well as survival and graft function at 1 month. Results: ECLS was initiated for extracorporeal cardiopulmonary resuscitation in 5 patients. The other patients needed ECLS due to hemodynamic deterioration during the assessment of brain death. We successfully retrieved 18 kidneys, 7 livers, and 1 heart from 9 donors. All organs were transplanted and none were discarded. Only 1 case of delayed kidney graft function was noted, and all 26 recipients were discharged without any significant complications. Conclusion: The benefits of protecting the vital organs of donors is significant, and ECLS for organ preservation can be widely used in the transplantation field.

Technology Trends in Spent Nuclear Fuel Cask and Dry Storage (사용후핵연료 운반용기 및 건식저장 기술 동향)

  • Shin, Jung Cheol;Yang, Jong Dae;Sung, Un Hak;Ryu, Sung Woo;Park, Yeong Woo
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.16 no.1
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    • pp.110-116
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    • 2020
  • As the management plan for domestic spent nuclear fuel is delayed, the storage of the operating nuclear power plant is approaching saturation, and the Kori 1 Unit that has reached its end of operation life is preparing for the dismantling plan. The first stage of dismantling is the transfer of spent nuclear fuel stored in storage at plants. The spent fuel management process leads to temporary storage, interim storage, reprocessing and permanent disposal. In this paper, the technical issues to be considered when transporting spent fuel in this process are summarized. The spent fuels are treated as high-level radioactive waste and strictly managed according to international regulations. A series of integrity tests are performed to demonstrate that spent fuel can be safely stored for decades in a dry environment before being transferred to an intermediate storage facility. The safety of spent fuel transport container must be demonstrated under normal transport conditions and virtual accident conditions. IAEA international standards are commonly applied to the design of transport containers, licensing regulations and transport regulations worldwide. In addition, each country operates a physical protection system to reduce and respond to the threat of radioactive terrorism.

Development of Precision Drilling Machine for the Instrumentation of Nuclear Fuels (핵연료계장을 위한 정밀 드릴링장치 개발)

  • Hong, Jintae;Jeong, Hwang-Young;Ahn, Sung-Ho;Joung, Chang-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.2
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    • pp.223-230
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    • 2013
  • When a new nuclear fuel is developed, an irradiation test needs to be carried out in the research reactor to analyze the performance of the new nuclear fuel. In order to check the performance of a nuclear fuel during the irradiation test in the test loop of a research reactor, sensors need to be attached in and out of the fuel rod and connect them with instrumentation cables to the measuring device located outside of the reactor pool. In particular, to check the temporary temperature change at the center of a nuclear fuel during the irradiation test, a thermocouple should be instrumented at the center of the fuel rod. Therefore, a hole needs to be made at the center of fuel pellet to put in the thermocouple. However, because the hardness and the density of a sintered $UO_2$ pellet are very high, it is difficult to make a small fine hole on a sintered $UO_2$ pellet using a simple drilling machine even though we use a diamond drill bit made by electro deposition. In this study, an automated drilling machine using a CVD diamond drill has been developed to make a fine hole in a fuel pellet without changing tools or breakage of workpiece. A sintered alumina ($Al_2O_3$) block which has a higher hardness than a sintered $UO_2$ pellet is used as a test specimen. Then, it is verified that a precise hole can be drilled off without breakage of the drill bit in a short time.

Study on the Decontamination of Primary Cooling Pump in HANARO (하나로 1차 냉각펌프 제염에 대한 고찰)

  • An Jung-Sug;Lee Kyung-Ho;Kim Kwang-Dug;Park Young-Chul
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • pp.21-29
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    • 2005
  • The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. Recently, ten years after the initial operation of the HANARO, one of the two primary cooling pumps was decontaminated for overhaul maintenance in 2004. Before decontamination exposure doserate and surface contamination level of primary cooling pump measured at 4 points. After final decontamination exposure doserate and surface contamination level of primary cooling pump remeasured by same method done before. It is easy to decontaminate the out side exposed surfaces of the pump, but it is difficult to approach the inside surface due to double volute installed in the casing. Therefore, a new decontamination facility has been developed to solve this problem. A concentrated de-contaminant (DX-300) is rotated in the closed pump casing by the impeller actuated by a temporary motor. Nuclide particles are removed by the emulsification effect of the de-contaminant and the surface contaminants are chemically removed from the pump by the corrosion and dissolution effect. The inside surfaces of the primary cooling pump have been decontaminated by using the facility. As results, the contamination level of the inside surfaces was maintained below the surface contamination limit.

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