• Title/Summary/Keyword: 시설소개

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A study on the reliability enhancement of Ultrasonic water treatment system to boiler (보일러 초음파 수처리장치의 신뢰성향상에 관한 연구)

  • Kim, Dae-Ryong;Lee, Keun-Oh
    • Journal of Energy Engineering
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    • v.22 no.3
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    • pp.287-293
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    • 2013
  • This study was carried out to diminish the formation of scale in boilers which is one of the defect elements when they are operating. The defect relating to scale can cause a fatal impact on the explosion of boilers due to the overheating of their tubes, or it can affect the flow of water inside boilers with its bad circulation and result in a disparity of water inside the equipment. Heat transfer in the scale is low comparing to the boiler material, so it can lead to energy losses and has also impact on the global warming. In 2005, the Korean government introduced a system which requires boiler users to install the equipment which can prevent or eliminate the formation of scale to improve the management of water quality in boilers. The study on the techniques for preventing or eliminating the formation of scale started in 1821 and since then subsequently there have been lots of similar studies. The first one was about the scale reduction using potato starch. Since an ultrasonic scale preventer developed by a scientist from a Russian acoustic institute was introduced in1993, a variety of equipment of this kind have been disseminated in Korea. There has been a need to demonstrate the condition for the best performances of such equipment. Boilers are mostly composed of the main body and 288 the tube with a circular curved surface. I carried out a demonstration study on a circular tube which affects the scale defect the most among the boiler components. As a result of it, I found out the fact that the ultrasonic wave needs to reach a certain level of sound pressure and frequency to affect the formation of scale.

An Approximate Estimation of Snow Weight Using KMA Weather Station Data and Snow Density Formulae (기상청 관측 자료와 눈 밀도 공식을 이용한 적설하중의 근사 추정)

  • Jo, Ji-yeong;Lee, Seung-Jae;Choi, Won
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.22 no.2
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    • pp.92-101
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    • 2020
  • To prevent and mitigate damage to farms due to heavy snowfall, snow weight information should be provided in addition to snow depth. This study reviews four formulae regarding snow density and weight used in extant studies and applies them in Suwon area to estimate snow weight in Korea. We investigated the observed snow depth of 94 meteorological stations and automatic weather stations (AWS) data over the past 30 years (1988-2017). Based on the spatial distribution of snow depth by area in Korea, much of the fresh snow cover, due to heavy snowfall, occurred in Jeollabuk-do and Gangwon-do. Record snowfalls occurred in Gyeongsangbuk-do and Gangwon-do. However, the most recent heavy snowfall in winter occurred in Gyeonggi-do, Gyeongsangbuk-do, and Jeollanam-do. This implies that even if the snow depth is high, there is no significant damage unless the snow weight is high. The estimation of snow weight in Suwon area yielded different results based on the calculation method of snow density. In general, high snow depth is associated with heavy snow weight. However, maximum snow weight and maximum snow depth do not necessarily occur on the same day. The result of this study can be utilized to estimate the snow weight at other locations in Korea and to carry out snow weight prediction based on a numerical model. Snow weight information is expected to aid in establishing standards for greenhouse design and to reduce the economic losses incurred by farms.

Nanocommunication Design in Graduate-Level Education and Research Training (대학원 수준 교육과 연구 훈련에서의 나노소통 설계)

  • Itoh, Tadashi;Akai, Hisazumi;Takeda, Seiji;Ogawa, Hisahito;Ichikawa, Satoshi;Geshi, Masaaki;Ara, Masato;Niioka, Hirohiko
    • Journal of the Korean Vacuum Society
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    • v.19 no.6
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    • pp.423-431
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    • 2010
  • In order to teach the accumulated knowledge of nanoscience, nanoengineering and nanotechnology to graduate school students and young scientists with the sense of public engagement, Osaka University started from 2004 to prepare and offer various kinds of education and training programs such as trans-disciplinary graduate-school minor program, evening course refresher program, short-term international research training program, etc. It offers a series of lectures, partly broadcasted live to satellite classrooms. In addition, the students can join intensive hands-on training programs using modern facilities, allowing them to design, fabricate, measure, characterize and functionalize nanomaterials and nanodevices. In addition, there are four specially designed lectures and research training programs aimed for nanocommunication including social, legal and ethical relationship: "Nanotechnology Career-up Lectures", "Social Engagement on Nanotechnology", "Road Map Design on Nanotechnology", and "Project-Aimed Learning and Training Programs (PAL)". The outline of the whole programs is described together with the specialized programs for nanocommunication.

Introduction of Acquisition System, Processing System and Distributing Service for Geostationary Ocean Color Imager (GOCI) Data (정지궤도 해색탑재체(GOCI) 데이터의 수신.처리 시스템과 배포 서비스)

  • Yang, Chan-Su;Bae, Sang-Soo;Han, Hee-Jeong;Ahn, Yu-Hwan;Ryu, Joo-Hyung;Han, Tai-Hyun;Yoo, Hong-Rhyong
    • Korean Journal of Remote Sensing
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    • v.26 no.2
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    • pp.263-275
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    • 2010
  • KOSC(Korea Ocean Satellite Center), the primary operational organization for GOCI(Geostationary Ocean Color Imager), was established in KORDI(Korea Ocean Research & Development Institute). For a stable distribution service of GOCI data, various systems were installed at KOSC as follows: GOCI Data Acquisition System, Image Pre-processing System, GOCI Data Processing System, GOCI Data Distribution System, Data Management System, Total Management & Control System and External Data Exchange System. KOSC distributes the GOCI data 8 times to user at 1-hour intervals during the daytime in near-real time according to the distribution policy. Finally, we introduce the KOSC website for users to search, request and download GOCI data.

Application Examples of Daecheong Dam for Efficient Water Management Based on Integrated Water Management (통합물관리 기반 효율적 물관리를 위한 대청댐 실무적용 사례)

  • Kang, Kwon-Su;Heo, Jun-Haeng
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.85-85
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    • 2017
  • 효율적 물관리란 거대한 물순환 과정에서 인간이 편안한 삶을 사는데 필요한 물의 이용효율을 극대화하는 것이다. 과거의 물관리는 이원화된 수량과 수질관리, 수량중심에서는 용수공급과 홍수조절이 주요한 관심사였다. 현재는 과거의 물관리에 친수와 환경을 더한 복잡한 분야로 확대되고 있다. 통합물관리란 물을 최적으로 관리하기 위해 물관리 이해당사자간의 소통과 물 기술의 고도화를 기반으로 기존에 분산된 물관리 구성요소들(시설 정보, 수량 수질 등)을 권역적으로 관리하는 것을 말한다. 본 연구에서는 대청댐 방류에 따른 금강 하류부의 홍수추적을 위해 수행한 댐하류 소유역별 강우량 빈도분석 과정, 용담댐 방류를 고려한 대청댐 홍수도달시간 검토, Poincare Section과 신경망기법을 이용한 수문자료 예측, 추계학적 다변량 해석과 다변량 신경망해석에 의한 대청댐 유입량 산정과정, 보조여수로 건설에 따른 주여수로와 보조여수로간의 연계운영방안, 단계(관심, 주의, 경계, 심각)를 고려한 대청댐 확보수위 산정, 저수지 중장기 운영계획 수립과 댐 운영 기준수위를 결정하기 위해 누가차분방식으로 적용되는 갈수기 유입량 빈도분석에 대한 실무적용 사례를 소개하고자 한다. 강우량 빈도분석 과정은 L-모멘트방법(Hosking과 Wallis, 1993)을 적용하였고, 홍수도달시간 검토는 평균유속, 하류 수위상승 기점 영향검토, 수리학적 모형(FLDWAV, Progressive lag method 등)을 활용하였다. 카오스 이론을 도입하여 대청댐 수문자료의 상관성 검토 및 추계학적 모형을 이용한 모의발생을 유도하여 수문자료 예측을 시행하였다. 추계학적 모형과 신경망모형 연구의 대상은 대청댐으로, 시계열 자료는 댐의 월강우량, 월유입량, 최고기온, 평균기온, 최소기온, 습도, 증발량 등의 자료를 기반으로 하였다. 적용기간은 1981~2009년의 자료를 이용하여 2010년 1월부터 12월까지 12개월 동안의 월유입량을 예측하였다. 수문자료 해석의 기본이 되는 약 30년간의 자료를 이용하여 분석을 실시하였다. 대청댐의 유입량 예측을 위해 적용된 모형으로는 추계학적 모형인 ARMA모형, TF모형, TFN 모형 등이 적용되었고, 또한 신경망 모형의 종류인 다층 퍼셉트론, PCA모형 등을 활용하여 실측치와 가장 가깝게 근사화시키는 방법론을 찾고자 하였다. 또한, 기존여수로와 보조여수로 연계운영을 위해 3차원 수치해석을 통한 댐하류 안정성 검토 및 확보수위 산정을 통해 단계(관심, 주의, 경계, 심각)별로 대처가 가능한 수위를 산정하였다.

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Accumulation of Natural and Artificial Radionuclides in Marine Products around the Korean Peninsula: Current Studies and Future Direction (국내산 수산물 내 자연 및 인공방사능 축적 연구 현황 및 향후 연구 방향)

  • Lee, Huisu;Kim, Intae
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.5
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    • pp.618-629
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    • 2021
  • The Fukushima nuclear power plant (NPP) accident caused by the East Japan Earthquake in 2011 and the recent increase in the frequency of earthquakes in Korea have caused safety concerns regarding radionuclide exposure. In addition, the Tokyo Electric Power Company (TEPCO) in Japan recently decided to release radionuclide-contaminated water from Fukushima's NPP into the Pacific Ocean, raising public concerns that the possibility of radionuclide contamination through both domestic- and foreign fishery products is increasing. Although many studies have been conducted on the input of artificial radionuclides into the Pacific after the Fukushima NPP accident, studies on the distribution and accumulation of artificial radionuclides in marine products from East Asia are lacking. Therefore, in this study, we attempted to explore recent research on the distribution of artificial radionuclides (e.g., 137Cs, 239+240Pu, 90Sr, and etc.) in marine products from Korean seas after the Fukushima NPP accident. In addition, we also discuss future research directions as it is necessary to prepare for likely radiation accidents in the future around Korea associated with the new nuclear facilities planned by 2030 in China and owing to the discharge of radionuclide-contaminated water from the Fukushima NPP.

A Study on Youth's Street Life Experience and Multifaceted Support Policy (청소년의 거리생활 경험과 지원정책에 관한 연구)

  • Kim, Woong-Soo;Bae, Seong-Chan
    • Journal of Digital Convergence
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    • v.17 no.6
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    • pp.417-426
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    • 2019
  • This researched is an investigation about the youths runaways street life experienced, the crimes committed through the influenced living in the street by looking into the effectiveness of the youth welfare and make an observation of their direction. The survey was conducted on young people who met in the youth shelter and outreach program, and finally analyzed 259 copies. The results of the study are as follows. First, When comparing the ages of the runaway youths if not properly given a support, services and prevention after running away from home, these youth will live their life in the street until their adolescents. Second, Runaway youth shelter has been providing the needs of those runaway youth who came in the shelter. However, it needs necessary new policy and services that will augment the support in solving problems of the youths when they visit youth shelter to ask for help and support. Third, It can be seen that the flight behavior after the street life is increased. They are in a situation where they have no choice but to join the juveniles for street life. Finally, Street life Youth self-reliance, support for living expenses, housing facilities, job opportunities, technical and job skill training were highly desired by the youths. Eventually, the intervention of youth living in street life requires a multifaceted support such as housing, labor, education, and welfare.

Touristic Aspects of Geological Heritages -Cretaceous Dinosaur Fossil Sites- (지질유산의 관광자원으로서의 특성과 활용 -국내 백악기 공룡화석산지를 중심으로-)

  • Paik, In Sung;Kim, Sook Ju;Huh, Min;Lee, Soo Jae;Kim, Hyun Joo;Lim, Jong Deok
    • Korean Journal of Heritage: History & Science
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    • v.43 no.1
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    • pp.4-27
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    • 2010
  • In this article, concepts, types, and aspects of geological heritage with increasing interests as utilization as tourist attractions domestically and internationally are introduced, and the characteristics of the interpretive facilities for geological heritages in western Australia, one of the most famous geotourism areas, are considered. Based on this, the potential geotourism for the Korean Cretaceous geological heritages including dinosaur fossil sites is discussed in diverse aspects including academic values, academic and tourism infrastructures, characteristics of geotourists, systematic devices for conservation of geological heritage, economic value, and sustainability as tourist attractions. Although the Korean Cretaceous geosites are not quite competent in their scale or diversity when compared to world-class geosites, convenient access, world-class unique geographical characteristics of each geosites, and relatively cheaper travelling expenses seems to be able to give the geotourism of the South Korean Cretaceous geosites a competitive edge, attractive for international and domestic tourists seeking unique experience of 'Age of dinosaurs' for short periods with easy access from metropolitan areas and low costs. Likewise, the development of geotourism for the Korean Cretaceous geosites can revitalize the geotourism industry in South Korea, contributing to the growth in job opportunities, including students majoring in geological sciences at University.

Development of Wide-Band Planar Active Array Antenna System for Electronic Warfare (전자전용 광대역 평면형 능동위상배열 안테나 시스템 개발)

  • Kim, Jae-Duk;Cho, Sang-Wang;Choi, Sam Yeul;Kim, Doo Hwan;Park, Heui Jun;Kim, Dong Hee;Lee, Wang Yong;Kim, In Seon;Lee, Chang Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.6
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    • pp.467-478
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    • 2019
  • This paper describes the development and measurement results of a wide-band planar active phase array antenna system for an electronic warfare jamming transmitter. The system is designed as an $8{\times}8$ triangular lattice array using a $45^{\circ}$ slant wide-band antenna. The 64-element transmission channel is composed of a wide-band gallium nitride(GaN) solid state power amplifier and a gallium arsenide(GaAs) multi-function core chip(MFC). Each GaAs MFC includes a true-time delay circuit to avoid a wide-band beam squint, a digital attenuator, and a GaAs drive amplifier to electronically steer the transmitted beam over a ${\pm}45^{\circ}$ azimuth angle and ${\pm}25^{\circ}$ elevation angle scan. Measurement of the transmitted beam pattern is conducted using a near-field measurement facility. The EIRP of the designed system, which is 9.8 dB more than the target EIRP performance(P), and the ${\pm}45^{\circ}$ azimuth and ${\pm}25^{\circ}$ elevation beam steering fulfill the desired specifications.

Borehole Elemental Concentration Logs: Theory, Current Trends and Next Level (암석구성성분검층: 원리, 연구동향 및 향후 과제)

  • Shin, Jehyun;Hwang, Seho
    • Geophysics and Geophysical Exploration
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    • v.22 no.3
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    • pp.149-159
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    • 2019
  • Borehole elemental concentration logging, measuring neutron-induced gamma rays by inelastic scattering and neutron capture interactions between neutron and formation, delivers concentrations of the most common elements found in the minerals and fluids of subsurface formation. X-ray diffraction and X-ray fluorescence analysis from core samples are traditionally used to understand formation composition and mineralogy, but it represents only part of formations. Additionally, it is difficult to obtain elemental analysis over the whole intervals because of poor core recovery zones such as fractures or sand layers mainly responsible for groundwater flow. The development of borehole technique for in situ elemental analysis plays a key role in assessing subsurface environment. Although this technology has advanced consistently starting from conventional and unconventional resources evaluation, it has been considered as exclusive techniques of some major service company. As regards domestic research and development, it has still remained an unexplored field because of some barriers such as the deficiency of detailed information on tools and calibration facility for chemistry and mineralogy database. This article reviews the basic theory of spectroscopy measurements, system configuration, calibration facility, and current status. In addition, this article introduces the domestic researches and self-development status on borehole elemental concentration tools.