• 제목/요약/키워드: Metal Obstacle Environment

검색결과 6건 처리시간 0.026초

금속 장애물 환경에서 토폴로지 안정성을 개선한 변형 LEACH 프로토콜 (Modified LEACH Protocol improving the Stabilization of Topology in Metal Obstacle Environment)

  • 이기원;이재기;곽광훈
    • 한국통신학회논문지
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    • 제34권12B호
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    • pp.1349-1358
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    • 2009
  • 선박 등에서의 컨테이너 적치환경은 전원공급의 한계 때문에 무선 센서 네트워크 기술이 이용된다. 이 경우 인프라 설치비용이나 어려움 때문에 많은 싱크노드 적용이 용이하지 않으므로 하나의 싱크노드에 수백에서 수천이라는 다수의 노드가 하나의 네트워크 구성에 참여하게 된다. 이런 대량의 노드들을 관리하기 위해 클러스터링 기반 Proactive 방식의 프로토콜이 적합하다. 하지만 컨테이너가 적치된 금속 장애물 환경에서는 전파의 간섭, 반사, 왜곡 등의 이유로 무선통신 환경이 불안정하다. 이에 따라 본 논문에서는 불안정한 무선통신의 신뢰성을 향상시키기 위해 기존의 변형 LEACH 프로토콜을 개선시켜 추가 변형된 LEACH 프로토콜을 제안한다. 제안 프로토콜에서는 링크 품질을 측정한 후 일정 품질 이상의 링크에만 연결설정을 하도록 구현하였다. 이를 통해 안정적인 토폴로지 형성을 유도하였으며, 기존의 프로토콜과 비교하였다. 비교 결과, 본 논문에서 제안한 프로토콜이 불안정한 무선통신 환경에서 기존의 프로토콜보다 안정적인 토폴로지를 형성함을 확인하였다.

플라즈마를 이용한 도시 쓰레기 소각재 용융처리 기술 (Slagging treatment of MSW incineration ash by plasma system)

  • 박현서;지규일;장준섭;전석구;배희주;김형진;이시창;주성준;신범수
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 1999년도 추계학술발표회
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    • pp.65-68
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    • 1999
  • A plasma melting system to vitrify ny ash from MSW(Municipal Solid Waste) incinerator has been operated in SHI(Samsung Heavy Industries) since 1996. Waste feeding rate was 200kg/hr. with maximum working power of 500㎾. Because of high melting temperature of fly ash, bottom ash was used as an additive to decrease melting temperature. Data analysis for discharged slag shows volume reduction up to 30% and no leaching of heavy metals such as Pb, Cd, Cr which were an obstacle for landfill and recycle. Atmospheric pollution gas like nitrogen oxides, carbon monoxide, and PCDD/PCDF were restrained below the regulatory limit.

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PEMFC용 금속분리판 코팅 기술 개발 : II. 코팅 금속분리판 연료전지 성능 특성 연구 (Development of Surface Coating Technology for Metallic Bipolar Hate in PEMFC : II. Study on the PEMEC Performance of Coated Metallic Bipolar Plate)

  • 윤용식;정경우;양유창;안승균;전유택;나상묵
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 추계학술대회
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    • pp.352-355
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    • 2006
  • As the stainless steel has good corrosion resistance, mechanical property and ease of manufacture, it has been studied as the candidate material of metallic bipolar plate for automotive PIMFC. But, metal is dissolved under fuel cell operating conditions Dissolved ions contaminate a membrane electrode assembly (MEA) and, decrease the fuel cell performance. In addition, metal oxide formation on the surface of stainless steel increases the contact resistance in the fuel cell. These problems have been acted as an obstacle in the application of stainless steel to bipolar plate. Therefore, many kinds of coating technologies have been examined in order to solve these problems. In this study, stainless steel was coated in order to achieve high conductivity and corrosion resistance by several methods. Contact resistance was measured by using a tensile tester and impedance analyzer Corrosion characteristics of coated stainless steel were examined by Tafel-extrapolation method from the polarization curves in a solution simulating the anodic and cathodic environment of PEMFC. Fuel cell performance was also evaluated by single cell test. We tested various coated metal bipolar plate and conventional and graphite were also tested as comparative samples. In the result, coated stainless steel bipolar plate exhibited better cell performance than graphite to bipolar plate.

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절삭가공과 저융점금속에 의한 쾌속제작용 자동충진공정 개발 (Development of Automatic Filling Process using Low-Melting Point Metal for Rapid Manufacturing with Machining Process)

  • 신보성;양동열;최두선;김기돈;이응숙;제태진;황경현
    • 한국정밀공학회지
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    • 제19권3호
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    • pp.88-94
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    • 2002
  • Recently, the life cycle and the lead-time of a product are to be shortened in order to satisfy consumer's demand. It is thus important to reduce the time and cost in manufacturing trial products. Several technique have been developed and successfully commercialized in the market of RPM(Rapid Prototyping and Manufacturing). However, most commercial systems currently use resins or waxes as the raw materials. So, the limited mechanical strength for functional testing is regarded as an obstacle towards broader application of rapid prototyping techniques. To overcome these problems, high-speed machining technology is being investigated worldwide for rapid manufacturing and even for direct rapid tooling application. In this paper, some fundamental experiments and analyses are carried out to obtain the filling time, materials, method, and process parameters for HisRP(High-Speed RP) process. HisRP is a new RP process that is combined high-speed machining with automatic filling. In filling process, Bi58-Sn alloy is chosen as filling material because of the properties of low-melting point, low coefficient of thermal expansion and no harm to environment. Also the use of filling wire it if advantage since it needs simple and flexible mechanism. Then the rapid product, for example a skull, is manufactured for aluminum material by HisRP process with an automatic set-up device thor 4-faces machining.

유기산, 산화음이온 및 금속 산화물 간의 근권 내 상호작용 연구를 위한 계산화학과 적외선 분광학에 관한 총설: 기본적인 원리와 스펙트럼 처리 (Reviews in Infrared Spectroscopy and Computational Chemistry to Reveal Rhizospheric Interactions among Organic Acids, Oxyanions and Metal oxides: Fundamental Principles and Spectrum Processing)

  • 한준호;노희명
    • 대한환경공학회지
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    • 제39권7호
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    • pp.426-439
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    • 2017
  • 이 총설은 근권에서 일어나는 유기산, 산화음이온, 그리고 금속 산화물 간의 상호작용을 이해하는데 활용하고 있는 적외선 분광학과 계산화학에 대한 기본적 원리, 역사, 적용 분야, 장점, 그리고 단점에 대해 최근 연구들을 바탕으로 요약하였다. 식물의 유기산과 금속 산화물은 토양 환경에서 산화음이온의 유효도와 이동성을 결정하기 때문에, 산화음이온의 환경 내 거동을 이해하기 위해서는 계면에서 이들의 상호작용을 이해하는 것이 중요하다. 적외선 분광학의 감쇠 전반사 기법은 계면에서 일어나는 화학적인 반응을 측정하는 강력한 도구이지만, 광학적 특성들이 실험 설계와 대상에 따라 매우 다르게 나타날 수 있으므로 이를 이용한 측정은 까다롭다. 전반사에 의해 발생하는 소멸파의 침투 깊이가 가장 중요한 매개 변수인데, 침투 깊이는 적외선의 입사각과 대상 파장, 그리고 매질의 굴절률에 따라 결정된다. 또한, 적외선을 이용하여 계면에서의 화학반응을 분석할 때 겹쳐서 발생하는 스펙트럼을 해석하는 것 역시 큰 문제이기 때문에, 겹쳐 나타나는 스펙트럼을 해석하여 밴드를 검출하고, 이 스펙트럼을 deconvolution하는 것이 필수적이다. 본 총설에서는 적외선스펙트럼을 처리하는 기본적인 절차와, 밴드 검출에 사용하는 네가지 방법인 도함수 분광학과 이차 상관 분광학, multivariate curve resolution, 계산 화학을 액체상에 존재하는 인산염 종분화로 설명하였다. 스펙트럼 처리와 계산 화학을 조합하였을 때 간단한 계에서 측정한 겹쳐진 스펙트럼 결과는 해석할 수 있었지만, 자연과 같은 복잡계에서 측정한 겹쳐진 스펙트럼을 해석하는 것은 여전히 불가능한 상황이다. 그러나 향후 분석 및 신호 처리 기술 발달에 따라 복잡계뿐만 아니라 자연계에서 일어나는 계면 반응을 해석할 수 있을 것으로 기대한다.

근로자의 산업보건 지식과 태도에 관한 조사연구 (A Survey on the Knowledge and Attitude of Workers Concerning Occupational Health)

  • 박영식;조수열;남철현
    • 한국환경보건학회지
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    • 제18권2호
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    • pp.3-18
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    • 1992
  • This research was carried out on 1,017 production workers for four months from May to August, 1991, to search more effective management method of their health by grasping their knowledge and attitude on industrial health. The results of this study can be summarized as follows: 1. As for general characteristics, 74.2% were male and 25.8% were female among the 1,017 workers. The two largest age groups were 30~39, 38.7%. As for education level, graduation from high school was 58.6%, 61.2% were married, 35.9% owned their house, and workers who worked more than 1 year less than 5 years was 52.9%, workers who worked 8 hours a day was 46.7%, the largest group income level was 60~69 thousand won 21.2%, and the degree of satisfaction with work was ordinary, 45.6%. 2. The degree of recognition concerning occupational diseases was 92.5% at a very high rate. Causes of occupational diseases under the present work field were in order of noise, dust, heavy metal. The largest group of the counterplan for prevention was an improvement of working environment, 62.0%. 3. The major cause that threatens worker's health was poor working environment, 31.4%. As the best method for workers' health management, working environment management was pointed. 4. As for health examination result, the response that it is of use to health management was 53.8%. As for examination method and result, 42.7% responded that they are formal. The practice period was more than once every six months as the largest group, and the highest desire for improvement was that they wants an exact information of the result. 5. 49.3% of the respondents know about the measurement of working environment an the response that the measurement is necessary to improve working environment was 57.9%, and that the results from the measurement were reflected on improvement an management 57.5%. Appropriate period to take a measurement was more than once per six months, 40.2% and per three months, 29.1%. 6. As for safety and halth instruction, 34.5% were educated for both, 38.2% for only safety education and just 4.6% for only health education. 51.9% responded that they had never been educated out of work place. The period of its practice was more than once a month, 39.5% and every three months, 21.3%. 7. The importance of safety and health showed that the one is equal to the other, 59.8%, that the one is more important, 29.6%, and that other is more important, 7.6%. 67.7% said the necessity of a safety and health manager. 8. In spite of more or less health obstacle of work environment, 14.9% of the respondents wanted to overwork to gain an allowance for over-time work, 39.9% didn't, and 40.2% according to condition and state. 9. As the most important cause of industrial accident, 40.2% indicated unsafe behavior. As for the individual protective instrument, 66.1% of all the respondents said they have worn it to protect industrial diseases. 10. As for the degree of understanding of the contents in Industrial Safety and Health Law and Industrial Law of Accident Insurance, an affirmative response was respectively 49.3% and 50.8% and the sources of safety-health information were televisions and radios, 28.0%. Therefore, it is necessary that we do positive working environmental improvement, continuous management and health education's inforcement to increase their health and prevent occupational diseases.

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