• 제목/요약/키워드: Flow management

검색결과 3,544건 처리시간 0.036초

International Case Studies on the Eco-friendly Energy Towns with Hybrid Thermal Energy Supply System and Borehole Thermal Energy Storage (BTES) (친환경에너지타운에서 보어홀지중열 저장(BTES) 활용 융복합 열에너지 공급 시스템 사례 연구)

  • Shim, Byoung Ohan
    • Economic and Environmental Geology
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    • 제51권1호
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    • pp.67-76
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    • 2018
  • This study reviews three eco-friendly energy towns with hybrid thermal energy supply systems and borehole thermal energy storage (BTES) in Canada and Denmark. The district heating and cooling systems were designed by using multi-source energy for the higher efficiency and reliability as well as environment. ADEU (Alexandra District Energy Utility) located at the developing area in the city of Richmond, Canada was designed to supply district energy with the installation of 726 borehole heat exchangers (BHEs) and a backup boiler using natural gas. DLSC (Drake Landing Solar Community) located in the town of Okotoks, Canada is a district system to store solar thermal energy underground during the summer season by seasonal BTES with 144 BHEs. Brædstrup Solpark district heating system located in Denmark has been conducted energy supply from multiple energy sources of solar thermal, heat pump, boiler plants and seasonal BTES with 48 BHEs. These systems are designed based on social and economic benefits as well as nature-friendly living space according to the city based energy perspective. Each system has the energy center which distribute the stored thermal energy to each house for heating during the winter season. The BHE depth and ground thermal storage volume are designed by the heating and cooling load as well as the condition of ground water flow and thermophysical properties of the ground. These systems have been proved the reliance and economic benefits by providing consistent energy supply with competitive energy price for many years. In addition, the several expansions of the service area in ADEU and Brædstrup Solpark have been processed based on energy supply master plan. In order to implement this kind of project in our country, the regulation and policy support of government or related federal organization are required. As well as the government have to make a energy management agency associated with long-term supply energy plan.

Estimation of Agricultural Water Quality Using Classification Maps of Water Chemical components in Seonakdong River Watershed (수질성분 분포도를 이용한 서낙동강 수계 농업용수 수질평가)

  • Ko, Jee-Yeon;Lee, Jae-Sang;Kim, Choon-Song;Jeong, Ki-Yeol;Choi, Young-Dae;Yun, Eul-Soo;Park, Seong-Tae;Kang, Hwang-Won;Kim, Bok-Jin
    • Korean Journal of Environmental Agriculture
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    • 제25권2호
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    • pp.138-146
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    • 2006
  • To understand the status of water quality and work out a suitable countermeasures in Seonakdong watershed which has poor agro- environmental condition because of severe point and non-point source pollution by popularized city and near sea, we investigated the pollution sources and water quality from '03 and '05 and the result were mapped with GIS and RS for end-users's convenient comprehense and conjunction of water quality and geological data. The most degraded tributary was Hogeo stream which was affected directly by highly popularized Gimhae city, the main pollution source of the watershed. The pollution of tributaries in watershed increased the T-N of main body that reached over 4 mg/L during dry season. Pyeonggang stream and the lower part of main water way were suffered from high salt contents induced near sea and the EC value of those area were increased to 2.25 dS/m. The delivered loads of T-N and T-P were largest in Joman river as 56% and 61% of total delivered loads 1mm tributaries because of lots of stream flow. When Management mandate for irrigation water in Seonakdong river watershed was mapped for estimating integrated water quality as the basis of classification of EC and T-N contents in water, Hogeo and Shineo catchments were showed the requiring countermeasures none against nutrients hazard and Pyeonggang catchment was the vulnerable zone against nutrients and salts hazard. As the result, Seonakdong watershed had very various status of water quality by characteristics of catchments and countermeasures for improving water quality and crop productivity safely should changed depend on that.

Effects of Dissolved Oxygen and Depth on the Survival and Filtering Rate and Pseudofeces Production of a Filter-feeding Bivalve (Unio douglasiae) in the Cyanobacterial Bloom (남조류 대발생 환경에서 수심과 용존산소 변화에 따른 담수산 이매패(말조개)의 생존율, 여과율 및 배설물 생산)

  • Park, Ku-Sung;Kim, Baik-Ho;Um, Han-Yong;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • 제41권spc호
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    • pp.50-60
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    • 2008
  • We performed the experiment to evaluate the effect of different DO concentrations (0.5, 4.5 and 9.0 $mgO_2L^{-1}$) and water depths (20, 50 and 80 cm) on the filtering rate, mortality, and pseudifeces production of Unio douglasiae against the cyanobacterial bloom (mainly Microcystis aeruginosa). A solitary-living bivalve U. douglasiae was collected in the upstream region of the North Han River (Korea). The harvested mussels were carefully transferred to the laboratory artificial management system, which was controlled temperature $(18{\pm}2^{\circ}C)$, flow rate (10L $h^{-1}$), food $(Chlorella^{TM})$, sediment (pebble and clay), light intensity (ca. $20{\mu}mol$ photons), and photocycle (12 L : 12 D). In the field observation, the mussel mortality was significantly correlated with water temperature, pH and DO concentration (P<0.05). The mortality was decreased with water depth; 65, 90, 80% of mortality at 20, 50, 80 cm water-depth, respectively. Filtering rate (FR) showed the highest value at 50 cm water depth, and thereby the concentration of chlorophyll-${\alpha}$ decreased continuously by 94% of the control at the end of the experiment. In contrast, FR decreased by 34% of the initial concentration at 20 cm water depth. Over the given water-depth range, the mussel FR ranged from $0.15{\sim}0.20L\;gAFDW^{-1}hr^{-1}$ during the 18hrs of experiment, and thereafter, they appeared to be approximately 0.11, 0.26 and 0.30 L $gAFDW^{-1}hr^{-1}$ at 20, 50 and 80cm water depth, respectively. FR was highest with the value of 0.46L $gAFDW^{-1}hr^{-1}\;at\;0.5mgO_2 L^{-1}$ at the early stage of the experiment, while it increased with DO concentration. Maximum pseudofaeces production was 11.2 mg $gAFDW^{-1}hr^{-1}\;at\;9.0mgO_2L^{-1}$. Our results conclude that U. douglasiae has a potential to enhance water quality in eutrophic lake by removing dominant cyanobacteria, but their effects vary with environmental parameters and the water depth at which they are located.

Rainfall and Hydrological Comparative Analysis of Water Quality Variability in Euiam Reservoir, the North-Han River, Korea (북한강 의암호의 수질 변동성에 대한 강우·수문학적 비교분석)

  • Hwang, Soon-Jin;Sim, Yeon Bo;Choi, Bong-Geun;Kim, Keonhee;Park, Chaehong;Seo, Wanbum;Park, Myung-Hwan;Lee, Su-Woong;Shin, Jae-Ki
    • Korean Journal of Ecology and Environment
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    • 제50권1호
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    • pp.29-45
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    • 2017
  • This study explored spatiotemporal variability of water quality in correspondence with hydro-meteorological factors in the four stations of Euiam Reservoir located in the upstream region of the North-Han River from May 2012 to December 2015. Seasonal effect was apparent in the variation of water temperature, DO, electric conductivity and TSS during the study period. Stratification in the water column was observed in the near dam site every year and vanished between August and October. Increase of nitrogen nutrients was observed when inflowing discharge was low, while phosphorus increase was distinct both during the early season with increase of inflowing discharge and the period of severe draught persistent. Duration persisting high concentration of Chl-a (>$25mg\;m^{-3}$: the eutrophic status criterion, OECD, 1982) was 1~2 months of the whole year in 2014~2015, while it was almost 4 months in 2013. Water quality of Euiam Reservoir appeared to be affected basically by geomorphology and source of pollutants, such as longitudinally linked instream islands and Aggregate Island, inflowing urban stream, and wastewater treatment plant discharge. While inflowing discharge from the dams upstream and outflow pattern causing water level change seem to largely govern the variability of water quality in this particular system. In the process of spatiotemporal water quality change, factors related to climate (e.g. flood, typhoon, abruptly high rainfall, scorching heat of summer), hydrology (amount of flow and water level) might be attributed to water pulse, dilution, backflow, uptake, and sedimentation. This study showed that change of water quality in Euiam Reservoir was very dynamic and suggested that its effect could be delivered to downstream (Cheongpyeong and Paldang Reservoirs) through year-round discharge for hydropower generation.

Dynamics of Phosphorus-Turbid Water Outflow and Limno-Hydrological Effects on Hypolimnetic Effluents Discharging by Hydropower Electric Generation in a Large Dam Reservoir (Daecheong), Korea (대청호 발전방류수의 인·탁수 배출 역동성과 육수·수문학적 영향)

  • Shin, Jae-Ki;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
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    • 제50권1호
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    • pp.1-15
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    • 2017
  • Daecheong Reservoir was made by the construction of a large dam (>15 m in height) on the middle to downstream of the Geum River and the discharge systems have the watergate-spillway (WS), a hydropower penstock (HPP), and two intake towers. The purpose of this study was to investigate the limnological anomalies of turbid water reduction, green algae phenomenon, and oligotrophic state in the lower part of reservoir dam site, and compared with hydro-meteorological factors. Field surveys were conducted in two stations of near dam and the outlet of HPP with one week intervals from January to December 2000. Rainfall was closely related to the fluctuations of inflow, outflow and water level. The rainfall pattern was depended on the storm of monsoon and typhoon, and the increase of discharge and turbidity responded more strongly to the intensity than the frequency. Water temperature and DO fluctuations within the reservoir water layer were influenced by meteorological and hydrological events, and these were mainly caused by water level fluctuation based on temperature stratification, density current and discharge types. The discharges of WS and HPP induced to the flow of water bodies and the outflows of turbid water and nutrients such as nitrogen and phosphorus, respectively. Especially, when hypoxic or low-oxygen condition was present in the bottom water, the discharge through HPP has contributed significantly to the outflow of phosphorus released from the sediment into the downstream of dam. In addition, HPP effluent which be continuously operated throughout the year, was the main factor that could change to a low trophic level in the downreservoir (lacustrine zone). And water-bloom (green-tide) occurring in the lower part of reservoir was the result that the water body of upreservoir being transported and diffused toward the downreseroir, when discharging through the WS. Finally, the hydropower effluent was included the importance and dynamics that could have a temporal and spatial impacts on the physical, chemical and biological factors of the reservoir ecosystem.

The Electrochemical Chlorination for Marine Plankton Community Disinfection (해양 플랑크톤 군집의 전기분해 염소소독 효과)

  • Kang, Jung-Hoon;Shin, Kyoung-Soon;Hyun, Bong-Gil;Jang, Min-Chul;Kim, Eun-Chan;Chang, Man
    • Journal of the Korean Society for Marine Environment & Energy
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    • 제10권3호
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    • pp.127-137
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    • 2007
  • To confirm whether or not the Electrochemical Disinfection System (EDS) meet with the D-2 regulation established by IMO (International Maritime Organization), the biological treatment efficacy of the EDS was assessed using three groups of natural marine plankton (bacteria, $10-50\;{\mu}m$ and $>50\;{\mu}m$ sized organisms). Influent water was passed through the EDS under the flow velocity ($23.8\;m^3/hr$) and test design was consisted of control (no treatment) and experimental (10 ppm and 30 ppm) condition for total residual chlorine (TRC). And the biological condition of the influent water followed the standards established by the guidelines for the approval of ballast water management systems. The disinfection efficacy of the $10-50\;{\mu}m$ sized organisms (phytoplankton) was assessed by three kinds of measurements using photomicroscope, epifluorescence microscope and fluorometer (fumer Designs 10-AU). After being passed through the EDS, all motile phytoplankton lost their motility under photomicroscope, the colour of chlorophyll fluorescence fumed from red into green under epifluorescence, and the high chlorophyll fluorescence (Expt. 1: 6.95, Expt. 2: 7.11) detected by fluorometer decreased into value not detected. These results indicated phytoplankton community was totally killed after electrochemical disinfection treatment. Survivorship of the larger organisms than $50\;{\mu}m$ was determined based on the appendage's movement under a stereomicroscope. Natural assemblage collected from ambient seawater was killed shortly after being passed through the EDS, whereas some Artemia remained alive. However, no live Artemia was found after 24 hour further exposure to each TRC concentration (10 and 30 ppm) under darkness. After electrochemical treatment, the target bacteria such as aerobes, coliform and Escherichia coli were completely killed on the basis of CFU (colony forming unit) on Petrifilm plate ($3\;M^{TM}$) after 48 hr incubation. Moreover, no regrowth was found in the three groups of plankton during five days under additional exposure to the treated water. These results indicated that the disinfection efficiency of the EDS on the three groups of plankton satisfy D-2 regulation.

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Emergy Evaluation Overview of the Natural Environment and Economy of the Han River basin in Korea (한강유역의 자연환경과 사회경제활동에 대한 에머지 평가 - 한강유역 및 한강하구 관리를 위한 정책제언 -)

  • Kang, Dae-Seok
    • Journal of the Korean Society for Marine Environment & Energy
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    • 제10권3호
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    • pp.138-147
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    • 2007
  • An emergy concept was used to evaluate the environment and economy of the Han River basin in Korea and to suggest policy perspectives far the sustainable utilization of its environment and associated estuarine ecosystem. The economy of the basin used $5.19{\times}10^{23}\;sej/yr$ of emergy in 2005. The economy of the Han River basin was heavily dependent on outside energy sources from foreign countries and other parts of Korea, with internal sources, renewable and nonrenewable, contributing only 15.6% to the total emergy use. The basin's trade balance in terms of emergy showed trade surplus, whereas there was a deficit in monetary terms. The population of the Han River basin was far greater than the carrying capacity calculated using the emergy flow, with renewable carrying capacity only at 1.8% of the basin's population and developed carrying capacity at 14.3%. The economy of the basin imposed a substantial stress on its environment, with an environmental loading ratio of 54.8. Overall, the economy of the Han River basin was not sustainable with an emergy sustainability of 0.02. These are reflected in lower quality of living expressed in the emergy term than the national average. Deconcentration of population and economic activities is needed to reduce environmental stress on the environment of the basin and its valuable estuarine ecosystem. Policies to restore ecosystem productivity of the basin are also needed to ensure the sustainability of the basin's economic activities and the sustainable utilization of the Han River estuary. In this regard, it is urgently needed for the Korean government to implement sustainable management measures for the Han River estuary, a well-preserved, productive natural estuarine ecosystem in Korea.

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Study on the Indoor Environment and Status of Facilities and Equipments of Home Economics Practice Rooms of Middle Schools in Jeju Special Self-Governing Province (제주특별자치도 중학교 가정실의 실내환경 및 시설.설비 현황에 관한 연구)

  • Park, Min-Hye;Kim, Bong-Ae
    • Journal of Korean Home Economics Education Association
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    • 제19권3호
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    • pp.61-76
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    • 2007
  • The purpose of the study is to identify and understand problems existing in the middle school home economics practice rooms in Jeju Special Self-Governing Province. The findings are based on the examination and the analysis of the indoor environment and the condition of the facilities and equipment. Study method employs on-site research and a survey. The on-site research was conducted about temperature, humidity, intensity of illumination, and status of teaching instrument in 10 out of 41 middle schools in Jeju Special Self-Governing Province from August 16 to September 30, 2006. Meanwhile, the survey was implemented by mail for 95 teachers in charge of manual training and home economics education in 41 middle schools in Jeju from November 1 to 23, 2005. 64 questionnaires out of total 95 were collected, including those collected during the period of on-site research. Finally, 61 questionnaires which were effective among the answered ones were used for analysis. Collected materials were analyzed with the SPSS Win.12.0 program for frequency, percentile analysis. In conclusion, the study determines that the condition of the home economics practice rooms of the middle school in JSSGP in terms of temperature, humidity, lighting and ventilation is very inadequate. The structure of the practice room represents an inefficient work flow pattern. Further, the facilities and equipment are in a very poor condition because the facilities are old and the retention rate of teaching tools is low. Therefore, to address these problems, the study suggests that improvements on the facilities and equipment should be made and teaching tools should be replenished in accordance with the industry standard.

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The physical geography in general:yesterday and tomorrow (자연지리학 일반: 회고와 전망)

  • Son, Ill
    • Journal of the Korean Geographical Society
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    • 제31권2호
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    • pp.138-159
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    • 1996
  • There has been a tendency for Geomorphology and Climatology to be dominant in Physical Geography for 50 years in Korea. Physical Geography is concerned with the study of the totality of natural environment through the integrated approaches. But, an overall direction or a certain paradigm could not be found, because major sub-divisions of Physical Geography have been studied individually and the subjects and the approaches in studying Physical Geography are enormously diverse. A consensus of opinion could not also exist in deciding what kind of the sub-divisions should be included in the physical geography in general and how those should be summarized. Furthermore it would be considered imprudent to survey the studies of Physical Geography besides those of Geomorphology and Climatology due to the small number of researchers. Assuming that the rest of Physical Geographical studies with the exception of Geomorphological and Climatological studies are the Physical Geography in general, the studies of Physical Geogrpahy in general are summarized and several aspects are drown out as follows. First the descliption of all possible factors of natural environments was the pattern of early studies of Physical Geography and the tendency is maintained in the various kinds of research and project reports. Recently Physical Geographers have published several introductory textbooks or research monographs. In those books, however, the integrated approaches to Physical Geography were not suggested and the relationship between man and nature are dealt with in the elementary level. Second, the authentic soil studies of Physical Geographers are insignificant, because the studies of soil in Physical Geography have been mostly considered as the subsidiary means of Geomorphology Summarizing the studies of Soil Gegraphy by physical geographers and other Pedologists, the subjects are classified as soil-forming processes, soil erosions, soil in the tidal flat and reclaimed land, and soil pollution. Physical Geographers have focused upon the soil-forming processes in order to elucidate the geomorphic processes and the past climatic environment. The results of other subjects are trifling. Thirdy Byogeygrayhers and the results of studies are extremely of small number and the studies of Biogeography in Korea lines in the starting point. But, Biogeography could be a more unifying theme for the Physical-human Geography interface, and it would be expected to play an active part in the field of environmental conservation and resource management. Forth, the studies of Hydrogeography (Geographical Hydrology) in Korea have run through the studies of water balance and the morphometric studies such as the drainage network analysis and the relations of various kinds of morphometric elements in river. Recently, the hydrological model have introduced and developed to predict the flow of sediment, discharge, and ground water. The growth of groundwater studies is worthy of close attention. Finally, the studies on environmental problems was no mole than the general description about environmental destruction, resource development, environmental conservation, etc. until 1970s. The ecological perspectives on the relationship between man and nature were suggested in some studies of natural hazard. The new environmentalism having been introduced since 1980s. Human geographers have lead the studies of Environmental Perception. Environmental Ethics, Environmental Sociology, environmental policy. The Physical geographers have stay out of phase with the climate of the time and concentrate upon the publication of introductory textbooks. Recently, several studies on the human interference and modification of natural environments have been made an attempt in the fields of Geomorphology and climatology. Summarizing the studies of Physical Geography for 50 years in Korea, the integrated approaches inherent in Physical Geography disappeared little by little and the majol sub-divisions of Physical Ceography have develop in connection with the nearby earth sciences such as Geology, Meteorology, Pedology, Biology, Hydrology, etc been rediscovered by non-geographers under the guise of environmental science. It is expected that Physical Geography would revive as the dominant subject to cope with environmental problems, rearming with the innate integrated approaches.

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Right of disposition of cargo and Air waybill (송하인의 운송물 처분청구권과 항공화물운송장)

  • Nam, Hyun-Sook;Choi, June-Sun
    • The Korean Journal of Air & Space Law and Policy
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    • 제30권2호
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    • pp.177-199
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    • 2015
  • Commerce enriches human life enriched and within commerce, transportation of cargo is arguably the most important in business transactions. Traditionally, marine transport has been major commercial transaction, but carriage cargo by air is on the increase. While the fare for freight in comparison with that of ocean is higher, air freight has many benefits that justify the higher shipping fee; lower insurance premium, packing charges, inventory control, cost management and especially speed. Therefore, air freight transport is accumulating gradually. An air waybill(AWB) is needed in the air transport flow. It is a nonnegotiable security, so the holder cannot transfer of a right to a third party. Some scholars suggest that a negotiable AWB is needed. However, it seems nearly impossible to do so; an e-AWB use shows a gain in numbers, even if it has not met expectations. Going forward, it would appear reasonable to conduct a follow-up study on the utility and legal problem for e-AWB. After sending goods, the consignor has the right of disposition of cargo in some cases, and more research is necessary, because it is related to change of ownership and a trade settlement. According to WATS (World Airlines Transport Statistics), the Korean Air took third place in international freight in 2014, and fifth in total, domestic and international to great acclaim. However, there is a lack of research supporting the business showing. It is hope that more studies on e-AWB, stoppage in transit, and a risk of outstanding amount, etc. connect to develop Korean air freight industry.