• Title, Summary, Keyword: Sediment cell

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Analysis on Shielding Effectiveness of Electromagnetic Wave in Fire Pipes (물이 채워진 소화 배관의 전파 차폐도 해석)

  • Kim, Yoon-Jeung
    • Fire Science and Engineering
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    • v.30 no.4
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    • pp.94-102
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    • 2016
  • When establishing shielding facilities for EMP protection, WBC effect is used to protect fire pipes and honeycomb cells are inserted into the fire pipes to improve the shielding effectiveness. At this point, the smaller unit cell of honeycombs becomes, the more likely it interrupts the flow of water, which ends up clogging the fire pipes with sediment. To prevent this phenomenon, I would suggest a design method due to the pilarization loss of water molecules that contributes to increasing the size of honeycomb cells and remaining thin-walled sufficient for required shielding effectiveness.

Development of a Vegetation Buffer Strip Module for a Distributed Watershed Model CAMEL (유역모델 CAMEL 기반 식생여과대 모듈의 개발)

  • Park, Min-Hye;Cho, Hong-Lae;Koo, Bhon-Kyoung
    • Journal of Environmental Impact Assessment
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    • v.24 no.5
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    • pp.516-531
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    • 2015
  • In this study, a software module to predict the effectiveness of vegetation buffer strip (VBS) has been developed for using with Chemicals, Agricultural Management and Erosion Losses (CAMEL), a distributed watershed model. Most basic functions for the VBS module are same as CAMEL except functions newly developed to implement sedimentation enhancement by vegetation and level spreaders. For verification of the VBS module, sensitivity analyses for length, roughness, soil and vegetation type of VBS were carried out using a test grid cell. The surface discharge of sediment are highly sensitive to the roughness coefficient of VBS. The removal efficiencies of VBS for the surface discharges of sediment and TP are generally high regardless of environment changes. The surface discharges of TOC and TN are highly sensitive to the length and soil of VBS. The removal efficiencies of VBS for the surface discharges of TOC and TN are generally lower than those of sediment and TP. The newly developed VBS module reasonably simulates the removal efficiencies of surface discharges that vary according to the environment changes. It is expected that this VBS module can be used for evaluating the effectiveness of VBS-based best management practices to be applied to reduce pollution discharges from various non-point sources.

Study on Deodorizing Effects of Mume Fructus, Eriobotryae Folium, Acanthopanacis Cortex and Angelicae Dahuricae Radix for the Development of a Gargle Solution (구강함수제 개발을 위한 오매, 비파엽, 오가피, 백지의 구취억제효과 연구)

  • Jang, Sun-Young;Park, Jae-Woo;Yoon, Seong-Woo;Ryu, Bong-Ha;Kim, Jin-Sung
    • The Journal of Korean Medicine
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    • v.31 no.4
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    • pp.115-128
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    • 2010
  • Objectives: The aim of this study was to investigate deodorizing effectsof medicinal herbs (Mume Fructus, Eriobotryae Folium, Acanthopanacis Cortex, Angelicae Dahuricae Radix) for development of a gargle solution. Methods: 1. The antimicrobial effects of medicinal herbs were evaluated with the minimal bactericidal concentration (MBC) and the change of the number of viable cells in the herb extracts(1%) for 48 hrs against P. gingivalis 2561 and Pr. intermedia ATCC 25611. 2. Deodorizing activity of each herb and Garglin $Mint^{(R)}$gainst methyl mercaptan were analyzed by gas chromatography (GC). 3. We used the malodor modeling of the salivary sediment system with a Halimeter. 4. In the preliminary clinical study, the baseline concentration of VSC in the oral cavity of each subject was measured by Halimeter. Subjects would gargle for 30 seconds with cysteine. After 4 minutes subjects would gargle for 30 seconds with Garglin and herb extracts (2%). Subsequently, concentration of VSC were measured at 0, 4, 8, 12 and 20 minutes. Results: 1. MBC of Mume Fructusfor P. gingivalis 2561 was determined to be <1% and MBCs of Eriobotryae Folium for P. gingivalis 2561 and Pr. intermedia ATCC 25611 were determined to be <2% and <1%, respectively. Mume Fructus (1%) completely suppressed the P. gingivalis cell viability from 5 hrs and Eriobotryae Folium (1%) completely suppressed the Pr. intermedia cell viability from 48 hrs. 2. In GC analysis, deodorizing activities were 91.54% with Mume Fructus, 87.97% with Eriobotryae Folium, 100% with Acanthopanacis Cortex, 72.36% with Angelicae Dahuricae Radix and 40.54% with Garglin $Mint^{(R)}$. 3. In malodor modeling of the salivary sediment system, each of the medicinal herbs had significantly inhibitory effect on malodor formation (p<0.05). 4. In the preliminary clinical study, the concentration of VSC of the herb groups was significantly lower than of the control group, but not in Garglin $Mint^{(R)}$. Conclusions: Mume Fructus, Eriobotryae Folium, Acanthopanacis Cortex and Angelicae Dahuricae Radixhave deodorizing activities and potential as an effective mouthwash against oral malodor.

Cyanobacterial Development and Succession and Affecting Factors in a Eutrophic Reservoir (부영양 저수지에서 남조류의 발달과 천이 및 영향 요인)

  • Kim, Ho-Sub;Hwang, Soon-Jin;Kong, Dong-Soo
    • Korean Journal of Ecology and Environment
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    • v.40 no.1
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    • pp.121-129
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    • 2007
  • This study was conducted to evaluate the causes and effects of cyanobacterial development and succession in a shallow eutrophic reservoir from March 2003 to February 2004. Phytoplankton succession, sedimentation rate, and sediment composition were analyzed. Algal bioassay also was conducted with the consideration of light, water temperature and nutrients. Cyanobacteria dominated throughout the year, except for spring season (March${\sim}$April) in which diatoms and flagellates dominated. Total cell density increased in July and November when P loading through inflows was high. Oscillatoria spp. and Aphanizomenon sp. were dominant in May and June, respectively, but replaced with Microcystis spp. in July. Thereafter, Microcystis spp. sustained until December, and again shifted to Oscillatoria spp. and Aphanizomenon sp. The dominance of Oscillatoria spp. in May was accompanied with high TN/TP ratio and the increase of water temperature and light intensity. While the dominance of Microcystis spp. was related with relatively low TN/TP ratio, ranging from 46 to 13 (average: 27). The sedimentation rate was highest in March (0.6 m $day^{-1}$) when diatoms dominated. During the period of cyanobacterial dominance, relatively high sedimentation rate was observed in May (0.4 m $day^{-1}$) and October (0.36m $day^{-1}$). C/N ratio of the sediment ranged $6{\sim}8$. Inorganic P concentration in the pore water was low when DO concentration was < 2 mg $O_2$ $L^{-1}$ in the hypolimnion, reflecting the P release from the sediment. Cyanobacterial growth rate depended on phosphorus concentration and water temperature, and high P concentration compensated for the low temperature in the growth rate. Our results suggest that the potential of cyanobacterial development and substantiality in eutrophic reservoirs be high throughout the year, as being supplied with enough P, and emphasize the consideration of sediment man. agement for the water quality improvement and algal bloom control.

The Limnological Survey of a Coastal Lagoon in Korea (2): Lake Hyangho (동해안 석호의 육수학적 조사(2): 향호)

  • Kwon, Sang-Yong;Lee, Jae-Il;Kim, Dong-Jin;Kim, Bom-Chul;Heo, Woo-Myung
    • Korean Journal of Ecology and Environment
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    • v.37 no.1
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    • pp.1-11
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    • 2004
  • The limnological characteristics of a coastal lagoon were studied in Lake Hyangho, one of a series of brackish lagoons along the eastern coast of Korea. Phytoplankton community structure, physical factors, and chemical factors were surveyed from May 1998 through November 2002 on a two-month interval basis. Temperature, salinity, Secchi disc transparency, TN, TP, organic matter content of sediment, chlorophyll a concentration, dominant phytoplankton species, and phytoplankton cell density were measured. Salinity gradient was formed between the overlying freshwater stream water and the permeated seawater at the bottom. The chemocline was persistent at the depth of 2 ${\sim}$ 5 m that caused discontinuities of salinity, DO, and temperature profiles. The inversion of vertical temperature profiles with higher temperature in deeper layer was observed in early winter. Secchi disc transparency was very low with the range of 0.1 to 1.1m. TP, TN, and Chl. a concentration in the epilimnion was 0.011 ${\sim}$ 0.238 mgP $L^{-l}$, 0.423 ${\sim}$ 2.443 mgN $L^{-l}$, and 0.7 ${\sim}$ 145.2 mg $m^{-3}$, respectively. Sediment was composed of silt and coarse silt. COD, TP, and TN content of dry sediment were 19.7 ${\sim}$ 73.3 mg$O_2\;g^{-1}$, 0.61 ${\sim}$ 1.32 mgP $g^{-l}$ and 0.64 ${\sim}$ 0.88 mgN $g^{-l}$, respectively. Dominant phytoplankton species were chlorophytes (Ankistrodesmus falcatus) and cyanobacteria (Oscillatoria sp. and Merismopedia tennuissima). The total cell density was in the range of 560 ${\sim}$ 35,255 cells $mL^{-l}$.

Species classification of the toxic dinoflagellate Alexandrium tamarense and A. catenella based on their paralytic shellfish toxin profiles

  • Kim, Young-Soo;Kim, Chang-Hoon
    • Proceedings of the Korean Aquaculture Society Conference
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    • pp.128-128
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    • 2003
  • The annually outbreak of paralytic shellfish poisoning (PSP) were caused by toxic dinolagellate A. tamarense and A. catenella in Korea. The purpose of this study were to investigate the distribution of PSP-causative organisms, A. tamarense and A. catenella and their species classification. Sediment (Saemangeum, the south open sea) and water samples (southeastern coast) were sampled to establish clonal isolates in 2003. After isolation and purification, strains were cultured under $17^{\circ}C$, f/2 media, 14:10=L:D cycle. PST analysis and species identification were performed by HPLC-FD method and specific DNA probe, respectively. Thirty-ons strains were isolated from the Saemangeum reclamation, southeastern coast including Jinhae Bay and south open sea. PSTs were detected in all cultured strains. In eight strains from south offshore, major toxin components are GTX5, C1/2 and minors are GTX3/4, dcGTX3, neoSTX. Sixteen strains from south coastal area have GTX1/4, neoSTX, C1/2 as major toxin components and GTX2/3 as minors. Seven strains from the Saemangeum reclamation have GTX5, C1/2 as major toxin components and GTX1/2/3/4 as minors. Thus, among eight south offshore isolates, four A. tamarense have more toxic (38.31~l19.16 fmol.$cell^{-1}$) than A. catenella (3.78~13.13 fmol.$cell^{-1}$). With the previous results of different toxin composition, toxin components and toxin contents, .it is toxin profile that could used to diagnosis of regional toxic population and geographical distribution of both A. tamarense and A. catenella and their toxigenic strains.

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Report of 29 unrecorded bacterial species from the phylum Proteobacteria

  • Nam, Yoon-Jong;Beak, Kiwoon;Han, Ji-Hye;Park, Sanghwa;Lee, Mi-Hwa
    • Journal of Species Research
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    • v.7 no.1
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    • pp.60-72
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    • 2018
  • Our study aimed to discover indigenous prokaryotic species in Korea. A total of 29 bacterial species in the phylum Proteobacteria were isolated from freshwater and sediment of rivers and brackish zones in Korea. From the high 16S rRNA gene sequence similarity (${\geq}98.8%$) and formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to an independent and predefined bacterial species. To our knowledge, there is no official report or publication that has previously described these 29 species in Korea. Specifically, we identified 10, 12, and seven species of eight, 12, and seven genera that belong to classes Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria, respectively; all are reported as previously unrecorded bacterial species in Korea. The Gram reaction, colony and cell morphology, basic biochemical characteristics, isolation source, and strain IDs for each are also described.

Diversity of Deep-sea Piezophiles and Their Molecular Adaptations to High-pressure Environment

  • Kato, Chiaki;Sato, Takako;Tamegai, Hideyuki;Nakasone, Kaoru
    • Proceedings of the Microbiological Society of Korea Conference
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    • pp.80-82
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    • 2007
  • We have isolated numerous cold deep-sea adapted microorganisms (piezophilic, formerly referred to as "barophilic" bacteria) using deep-sea research submersibles. Many of the isolates are novel psychrophilic bacteria, and we have identified several new piezophilic species, i.e., Photobacterium profundum, Shewanella violacea, Moritella japonica, Moritella yayanosii, Psychromonas kaikoi, and Colwellia piezophila. These piezophiles are involving to five genera in gamma-Proteobacteria subgroup and produce significant amounts of unsaturated fatty acids in their cell membrane fractions to maintain the membrane fluidity in cold and high-pressure environments. Piezophilic microorganisms have been identified in many deep-sea bottoms of many of the world oceans. Therefore, these microbes are well distributed on our planet. One of the isolated deep-sea piezophiles, Shewanella violacea strain DSS12 is a psychrophilic, moderately piezophilic bacterium from a sediment sample collected at the Ryukyu Trench (depth: 5,110 m), which grows optimally at 30 MPa and $8^{\circ}C$ but also grows at atmospheric pressure (0.1 MPa) and $8^{\circ}C$. We have examined this strain to elucidate the molecular basis for gene regulation at different pressure conditions because this strain is useful as a model bacterium for comparing the various features of bacterial physiology under pressure conditions. In addition, we completed the sequencing of the entire genome of this piezophilic bacterium and we expect that many biotechnologically useful genes will be identified from the genome information.

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Characteristics of Membrane Filtration with Solid Loading in Lake Water (호소수의 고형물 부하 변동에 따른 막여과처리 특성)

  • Kim, Ji-Yeon;Lee, Hyeong-Ok;Hyun, Kil-Soo
    • Journal of Korean Society of Water Science and Technology
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    • v.25 no.3
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    • pp.3-9
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    • 2017
  • A lake water as drinking water source has been focused on the quality despite the limitation of the quantity. Different type and intensity of land use have distinct influence on the lake water quality. Degradation of water quality can result from multiple land use activities, including both point and nonpoint sources. In this study, the performances of membrane filtration (MF) using stirred dead end filtration cell on pollutants removal with solids and sediment loading in lake water was assessed. Batch tests were carried out with artificial water using lake water. Applied membrane permeate flux was $0.5m^3/m^2.d$. Influent concentrations were in the range of turbidity <500NTU, UV254 <$0.9cm^{-1}$, and dissolved organic carbon (DOC) <35 mg/L. As a result, the increase of influent turbidity increased transmembrane pressure (TMP) of MF process. MF process achieved the high removal for turbidity with removal efficiencies of >90%, while it achieved a relative low removal for DOC with removal efficiencies of <60%. In particular, the results showed that non-humic substance in DOC influenced on the increase of TMP.

Assessment of Soil-Erosion in Keumho River Watershed (금호강유역의 유사발생 발생 평가)

  • Kim, Seong won;Jeong, Anchul;Yu, Wansik;Jung, Kwansue
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.280-280
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    • 2017
  • 국내의 사면안정평가는 국토교통부, 국민안전처, 산림청 등의 주요 기관에서 사면을 구성하고 있는 토양특성과 사면경사 등을 평가할 수 있는 기준을 마련하고 있다. 대부분 경우 이 기준을 가지고 자연사면의 안정성에 대한 전반적인 평가가 이루어지고 있다. 하천관리에서는 다양한 요소들을 고려하여 계획이 수립되고 실행되고 있으며 이 중 산지와 기타 지역에서 유입유사는 그 정도에 따라 하천의 통수능력 감소와 하천생태계 교란 등의 많은 영향을 미치고 있다. 이러한 이유에서 유사는 하천관리에 있어 매우 중요한 관리 대상이다. 그러나 현재 평가기준을 이용하여 사면의 붕괴 및 취약정도를 판단할 수 있으나 유역의 유사발생여부를 평가하기에는 상당한 오류를 가지게 된다. 본 연구에서는 사면평가기준을 통한 1차적인 평가와 강우로부터 발생하는 토양침식과 퇴적을 분석 결과를 적용한 종합적인 2차적인 평가를 수행하였다. (1)기존에 사용하고 있는 사면안정평가기준을 가지고 대상유역인 금호강유역의 토양특성에 대한 등급을 분류한다. (2)토층, 토지이용, 빈도별 강우자료 등 다양한 인자를 고려할 수 있는 C-SEM(Cell-based Sediment Erosion Model)을 이용하여 침식 및 퇴적 깊이를 계산한다. (3)사용하고 있는 평가기준과 침식 및 퇴적깊이에 대한 분석결과를 조합하여 금호강유역에서의 유사발생 평가를 위한 지도를 작성한다. 이 연구는 국가에서 제공하고 있는 유역관련 자료를 이용하여 대상유역에서 유사발생을 평가하고 유사발생 관련인자를 대상으로 평가기준을 제안하였다.

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