• 한국농공학회논문집
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• 제48권3호
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• pp.73-82
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• 2006

Wind energy is one of the promising renewable energies that could provide electricity and other mechanical power. Wind energy market is dramatically growing in many European countries, but wind power is only 0.2% of the total renewable energy uses that is only about 2% of the primary energy consumption in Korea. It is widely accepted that wind resources fur power generation are only limited in some areas including coastal regions and mountainous areas in Gangwon province in Korea, particularly in terms of large scale wind power developments. In this study, wind velocity data were analyzed with respect to the potential utilization. The data provided from National Weather Service were used for the analysis. In addition, field wind data were also collected and analyzed for the comparison between the national data. The comparison showed that there were significant differences between the experimental station and the national station that are about 5km away. Annual average wind speed at the experimental station was less than 2 m/s, which is not enough fur wind power generation. It seemed that the topographic condition resulted in a significant difference in wind speed. When 600 W and 2.5 kW wind turbines were used, annual power productions were only 186 kWh and 598 kWh, respectively. When the average wind speed is lower, wind pumping is an alternative use of wind. At the experimental station, the average pumping rate of $3m^3/h$ at the head of 3 m was expected at a 2.5 m rotor under the conditions that efficiencies of the rotor and the pump were 40% and 80%, respectively. It did not seem that the wind pumping was not applicable at the station either. A higher wind speed was required to install the wind machines. Meanwhile, wind pumping would be applicable in conditions with lower pumping heads. Other applications were introduced far further wind energy utilization, including wind powered ventilation and friction heat generation in greenhouses.

• 한국습지학회지
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• 제13권1호
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• pp.35-44
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• 2011

기후변동에 따른 식생반응 및 그에 따른 물수지 동역학의 변화를 살펴볼 목적으로 본 연구에서는 식생의 물 이용가능성과 식생 생산량의 지역별 연별 변동성을 분석하였다. 유역의 식생 물이용의 대리변수로서 습윤량에 대한 기화량의 비로 표현되는 Horton 지수의 계산을 통하여 유역에서의 수문 분할과 그에 따른 식생의 물 이용 가능성에 대한 정량화를 시도하였다. 연별 Horton 지수의 추정결과 기후의 변동성과 비교하여 볼 때 상대적으로 일정한 값을 유지하고 있는 것을 살펴볼 수 있다. 이와 더불어 Horton 지수와 식생의 강우이용효율을 비교한 결과, 물 이용가능성에 따른 식생의 물 이용에 대한 흥미로운 패턴이 있음을 살펴볼 수 있었다. 물이 식생 성장에 제한요소가 될 경우 식생의 강우이용효율은 공통적인 최대값으로 수렴한다는 선행연구들의 결과를 본 연구를 통해서도 확인할 수 있다.

• 한국태양에너지학회 논문집
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• 제33권2호
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• pp.78-83
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• 2013

A methodology to predict the output performance of small hydro power plant using treated effluent in waste water treatment plant has been studied. Existing waste water treatment plant located in Kyunggi-Do were selected and the output performance characteristics for these plants were analyzed. .Based on the models developed in this study, the hydrologic performance characteristics for SHP sites have been analyzed. The results show that the flow duration characteristics of small hydropower plant for waste water treatment plant have quite differences compared with small hydropower plant for the river. As a result, it was found that the developed model in this study can be used to analyze the output characteristics for small hydro power in waste water treatment plant. Additionally, primary design specifications such as design flowrate, capacity, operational rate and annual electricity production were estimated and discussed. It was found that the models developed in this study can be used to decide the design performance of small hydropower plant for waste water treatment plant effectively.

• 환경생물
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• 제34권3호
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• pp.151-160
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• 2016

동해 울진 바다목장해역에서 크기별 식물플랑크톤 구성비 및 물질순환 특성을 파악하기 위한 현장조사는 2008년 4월에서 11월까지 4회 실시하였다. 바다목장해역 표층의 피코플랑크톤은 $0.03{\sim}0.87{\mu}g\;L^{-1}$의 변동 폭으로 연평균 $0.26{\mu}g\;L^{-1}$로 12.9% 구성비를 나타내었고, 나노플랑크톤은 $0.11{\sim}5.60{\mu}g\;L^{-1}$의 범위로 연평균 $1.32{\mu}g\;L^{-1}$로 65.0%, 네트플랑크톤은 nd~$4.68{\mu}g\;L^{-1}$의 범위로 연평균 $0.45{\mu}g\;L^{-1}$로 22.1%를 차지하였다. 10 m 수심도 다소 측정값의 차이는 있지만, 변동양상은 표층과 유사하였다. 시간적으로는 여름 네트플랑크톤 구성비가 30%까지 상승하였지만, 연간 피코 및 나노플랑크톤 구성비가 70% 이상으로 높은 특징을 보였다. 즉 동해 바다목장해역의 물질순환은 계절에 따라 다소 차이는 있지만, 전체적으로는 담수유입이 원활한 연안해역의 먹이사슬 구조 (bottom-up)보다는 빈영양 환경특성으로 생태계순환에 의한 물질순환 (top-down)에 더욱 크게 영향을 받는 것으로 판단할 수 있었다.

• Journal of Forest and Environmental Science
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• 제34권1호
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• pp.12-23
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• 2018

Quantitative information on biomass and available nutrients are essential for developing sustainable forest management strategies to regulate atmospheric carbon. An attempt was made at Chilapatta Reserve Forest in Duars region of West Bengal to quantify its above and below ground carbon along with available "N", "P" and "K" in the soil. Stratified random nested quadrats were marked for soil, biomass and litter sampling. Indirect or non-destructive procedures were employed for biomass estimation. The amount of these available nutrients and organic carbon quantified in soil indicates that the forest soil is high in organic carbon and available "K" and medium in phosphorus and nitrogen. The biomass, soil carbon and total carbon (soil C＋C in plant biomass) in the forest was 1,995.98, 75.83 and $973.65Mg\;ha^{-1}$. More than 90% of the carbon accumulated in the forest was contributed by the trees. The annual litter production of the forest was $5.37Mg\;ha^{-1}$. Carbon accumulation is intricately linked with site quality factors. The estimated biomass of $1,995.98Mg{\cdot}ha^{-1}$ clearly indicates this. The site quality factor i.e. tropical moist deciduous with optimum availability of soil nutrients, heavy precipitation, high mean monthly relative humidity and optimum temperature range supported luxuriant growth which was realized as higher biomass accumulation and hence higher carbon accumulated.

• 대한토목학회논문집
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• 제14권5호
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• pp.1159-1166
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• 1994

본 연구는 소수력발전소의 성능분석 및 예측기법에 관한 것으로 소수력발전소에서의 유량지속곡선을 작성하기 위해서 Weibull 분포의 누가밀도함수를 사용하여 강수자료를 특성화하였고, 특성화된 유량지속함수를 이용한 성능분석모형을 개발하였다. 또한 한강수계에 위치한 안흥소수력발전소를 대상으로 개발된 성능분석모형을 이용하여 발전소의 성능특성을 분석하였다. 분석결과, 수문자료가 부족한 소수력발전소의 경우, 개발된 성능분석모형을 이용하여 기존 소수력발전소에 대한 성능분석 뿐만 아니라 발전소의 초기 설계시 설계유량, 설비용량, 연 평균가동율 및 연간 발전량 등의 성능 예측에도 효과적으로 이용할 수 있음을 확인하였다.

• 한국해양학회지:바다
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• 제9권4호
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• pp.153-163
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• 2004

In order to estimate the nutrient flux of the Seomjin River into the coastal waters of South Sea, and to understand the estuarine reactions during mixing between river water and seawater, we collected surface water along the salinity gradient in the Seomjin River estuary from Mar. 1999 to Apr. 2001. We found that nitrate and silicate were delivered by fluvial input, while phosphate was, supplied from disposed wastes in the Gwangyang Bay. Mean annual flux of dissolved inorganic nitrogen (DIN), phosphate and silicate into the Gwangyang Bay was estimated 10.9 molesㆍsec$^{-1}$(4,820 tonnesㆍyr$^{-1}$), 0.07 molesㆍsec$^{-1}$(68 tonnesㆍyr$^{-1}$), 13.3 molesㆍsec$^{-1}$(11,747 tonnesㆍy$^{-1}$), respectively. An evident removal of phosphate, silicate and ammonium at the mid-salinity zone during the dry season was attributed to the active uptake of phytoplankton, and consequently nutrient flux into the Gwangyang Bay was low. Whereas, during the flood season in summer, conservative or additional distribution of the nutrients was observed in the estuary. As a rsult nutrient flux into the Gwangyang Bay was maintained high. High concentrations of chlorophyll a and the active removal of nutrient during the dry season at the mid-salinity zone suggest that nutrient distribution in the Seomjin River estuary was mainly controlled by biological processes and nutrient fluxes into the Gwangyang Bay might be significantly modified of by the primary production.

• 신재생에너지
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• 제5권4호
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• pp.39-43
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• 2009

The variation of inflow at stream and hydrologic performance for small scale hydro power(SSHP) plants due to climate change have been studied. The model, which can predict flow duration characteristic of stream, was developed to analyze the variation of inflow caused from rainfall condition. And another model to predict hydrologic performance for SSHP plants is established. Monthly inflow data measured at Andong dam for 32 years were analyzed. The existing SSHP plant located in upstream of Andong dam was selected and analyzed hydrologic performance characteristics. The predicted results from the developed models show that the data were in good agreement with measured results of long term inflow at Andong dam and the existing SSHP plant. Inflow and ideal hydro power potential had increased greatly in recent years, however, these did not lead annual energy production increment of existing SSHP plant. As a results, it was found that the models represented in this study can be used to predict the primary design specifications and inflow of SSHP plants effectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.74-75
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• 2021

In the recent 2017 annual average fine dust concentration (PM2.5) statistics released by the Organization for Economic Cooperation and Development (OECD), Korea has a high concentration of 25.14㎍/m3, which is about twice the average of 12.5㎍/m3 in OECD countries. Fine dust (PM2.5) is the main source of secondary pollutant production by the reaction of primary pollutants emitted from automobiles and thermal power plants, mainly composed of sulfates, nitrates, and organic carbon. The permeable block is an eco-friendly product that prevents rainwater from collecting on the surface of the road because it does not penetrate the groundwater properly, and is widely constructed on sidewalks or parking lots to recharge groundwater in case of rain. In addition, the pavement of the permeable block is a fundamental solution to reduce pollution by preventing rainwater from flowing into the stream, and it also has the advantage of easy replacement as well as low replacement costs. Therefore, this study was a basic experiment to produce permeable blocks mixed with TiO2 and diatomite to improve indoor air quality, and intended to analyze the flexural strength and compressive strength of permeable blocks mixed with TiO2.

• 상하수도학회지
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• 제38권1호
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• pp.29-38
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• 2024

Wastewater management is increasingly emphasizing economic and environmental sustainability. Traditional methods in sewage treatment plants have significant implications for the environment and the economy due to power and chemical consumption, and sludge generation. To address these challenges, a study was conducted to develop the Intermittent Cycle Extended Aeration System (ICEAS). This approach was implemented as the primary technique in a full-scale wastewater treatment facility, utilizing key operational factors within the standard Sequencing Batch Reactor (SBR) process. The optimal operational approach, identified in this study, was put into practice at the research facility from January 2020 to December 2022. By implementing management strategies within the biological reactor, it was shown that maintaining and reducing chemical quantities, sludge generation, power consumption, and related costs could yield economic benefits. Moreover, adapting operations to influent characteristics and seasonal conditions allowed for efficient blower operation, reducing unnecessary electricity consumption and ensuring proper dissolved oxygen levels. Despite annual increases in influent flow rate and concentration, this study demonstrated the ability to maintain and reduce sludge production, electricity consumption, and chemical usage. Additionally, systematic responses to emergencies and abnormal situations significantly contributed to economic, technical, and environmental benefits.