• 제목/요약/키워드: mixing measures

검색결과 59건 처리시간 0.025초

부순모래와 EEZ모래를 혼합사용한 모르타르의 기초물성에 관한 실험적 연구 (An Experimental Study on the Physical Properties of Mortar Using EEZ Sand and Crushed Sand)

  • 박종호;장재봉;나철성;조봉석;김재환;김무한
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2005년도 춘계 학술기술논문발표대회 논문집
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    • pp.33-36
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    • 2005
  • Recently, Trouble of sand supply is occurred according to exhaustion of natural sand resources. therefore, various measures are proposed for solution of trouble of sand supply. also the government settled trouble of sand supply through application of EEZ sand and crushed sand. but because both EEZ sand and crushed sand are poor against general sand, they lead to lowering of quality of ready-mixed concrete. Therefore, this study evaluated physical properties of mortar using EEZ sand and crushed sand and applied evaluation result to fundamental data The result of this study have shown that quality of mortar using EEZ sand and crushed sand independently is poor against general mortar. but, mortar flow and compressive strength is increased in case of mixing 222 sand and crushed sand properly.

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생물학적 노출평가를 통한 타겟 제조업 근로자의 공정별 인듐 노출위험성 조사 (Investigating the potential exposure risk to indium compounds of target manufacturing workers through an analysis of biological specimens)

  • 원용림;최윤정;최성렬;김은아
    • 한국산업보건학회지
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    • 제24권3호
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    • pp.263-271
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    • 2014
  • Objectives: Along with the several cases of pulmonary disorders caused by exposure to indium that have been reported in Japan, China, and the United States, cases of Korean workers involved in processes that require handling of indium compounds with potential risk of exposure to indium compounds have also been reported. We performed biological monitoring for workers in various target manufacturing processes of indium, indium oxide, and indium tin oxide(ITO)/indium zinc oxide(IZO) in domestic factories. Materials: As biological exposure indices, we measured serum concentrations of indium using inductively coupled plasma mass spectrometry, and Krebs von den Lungen 6(KL-6) and surfactant protein D(SP-D) using enzyme-linked immunosorbent assays. We classified the ITO/IZO target manufacturing process into powdering, mixing, molding, sintering, polishing, bonding, and finishing. Results: The powdering process workers showed the highest serum indium level. The mixing and polishing process workers also showed high serum indium levels. In the powdering process, the mean indium serum concentration in the workers exceeded $3{\mu}g/L$, the reference value in Japan. Of the powdering, mixing, and polishing process workers, 83.3%, 50.0%, and 24.5%, respectively, had values exceeding the reference value in Japan. We suppose that the reason of the higher prevalence of high indium concentrations in powder processing workers was that most of the particles in the powdering process were respirable dust smaller than $10{\mu}m$. The mean KL-6 and SP-D concentrations were high in the powdering, mixing, and polishing process workers. Therefore, the workers in these processes who were at greater risk of exposure to indium powder were those who had higher serum levels of indium, as well as KL-6 and SP-D. We observed significant differences in serum indium, KL-6, and SP-D levels between the process groups. Conclusions: Five among the seven reported cases of "indium lung" in Japan involved polishing process workers. Polishing process workers in Korea also had high serum levels of indium, KL-6, and SP-D. The outcomes of this study can be used as essential bases for establishing biological monitoring measures for workers handling indium compounds, and for developing health-care guidelines and special medical surveillance in Korea.

항만준설토의 콘크리트 혼합재로의 활용을 위한 기초적 연구 (A Fundamental Study for Beneficial Use of Dredged Material as a Concrete Admixture)

  • 오홍섭;오광진;이주원
    • 한국구조물진단유지관리공학회 논문집
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    • 제14권6호
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    • pp.132-141
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    • 2010
  • 최근 준설토의 발생량은 항만공사를 통하여 급격히 증가하고 있는 추세이다. 따라서 본 연구에서는 울산항과 부산항 준설토를 콘크리트 혼합재로의 혼입을 위한 연구를 수행하였다. 이를 위하여 준설토의 물리적 및 화학적 시험을 수행하였고, 그 결과를 바탕으로 하여 잔골재 대체재로서 준설토를 일정한 비율로 증가시켜 혼입한 모르터 시험체의 압축강도 시험을 수행하였다. 울산항 및 부산항 준설토 모두 혼입비율이 10%일 때 압축강도가 향상됨을 나타내었고, 무기질 실트 성분이 약 70% 함유되어 있는 부산항 준설토의 경우 잔골재의 대체량이 30% 일 때 압축강도가 증가하는 경향을 나타내었다. 또한 ICP 분석결과, 두 시료 모두 폐기물 해양배출처리기준과 토양오염 우려기준 및 대책기준에 만족하는 결과를 나타내어 콘크리트 재료로의 사용에 있어서 긍정적인 영향을 기대할 수 있었다.

미세 유체 기반의 형광 다중 암 진단 센서 플랫폼 설계 (Design of Fluorescence Multi-cancer Diagnostic Sensor Platform based on Microfluidics)

  • 이병권;칼리크 아민;정명영
    • 마이크로전자및패키징학회지
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    • 제29권4호
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    • pp.55-61
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    • 2022
  • 다중 암의 동시 진단 기술에 대한 관심이 전 세계적으로 증가하는 추세이며, 진단 난이도를 낮추기 위해 혈액과 같은 미량의 바이오 유체를 이용하여 질병을 진단하는 미세 유체 소자 기반의 액체 생검 기술이 연구되고 있다. 바이오 유체를 이용하여 형광 영상 등을 통해 분석물질의 농도를 측정하는 광학적 바이오 센싱에 있어 민감도를 향상시키기 위한 기술개발이 필요하다. 본 논문에서는 모세관력에 의한 자가구동 기반의 마이크로 채널의 기하학적 구조와 미세 유체 현상만으로 수동적 자기 혈장 분리 기술과 유체 혼합을 통한 분자 인식 활성화 기능을 구현하는 형광 다중 암 진단 센서 플랫폼 구조를 제안하고 설계하였다. 설계된 센서의 혈장 분리부의 성능에 영향을 미치는 파라미터를 확인하기 위해 채널의 수력학적 직경과 종횡비, 유체의 점도를 변수로 설정하여 딘 와류 형성 여부를 시뮬레이션을 통해 확인하였고 최적의 센서 플랫폼 구조를 제시하였다.

외국인 이주자의 관련 정책 및 지원활동에 관한 인식 (Foreign Immigrants' Recognition on Related Policies and Supporting Activities)

  • 최병두;김영경
    • 한국지역지리학회지
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    • 제17권4호
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    • pp.357-380
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    • 2011
  • 본 연구는 우리나라의 외국인 이주자 정책과 지원 활동이 어떤 성향을 가지고 있으며, 이러한 성향을 반영한 구체적인 정책 및 지원 프로그램들이 외국인 이주자들의 유형과 거주지역에 따라 어떻게 달리 인식되고 있는가를 고찰하고, 이들을 위해 필요한 정책의 개선 방안을 제시하고자 한다. 흔히 외국인 이주자 정책은 동화 모형, 차별적 배제 모형, 다문화 모형으로 구분되지만, 주변화의 성향이 함의된 것으로 이해된다. 또한 결혼이주자 정책은 동화 모형, 이주노동자 정책은 차별적 배제 모형, 전문직 이주자와 외국인 유학생 정책은 (거의 부재한 상태에서) 다문화주의적 성향을 가진 것으로 이해되지만, 설문조사에 의하면 외국인 이주자들은 관련 정잭에 대해 이러한 성향이 혼재된 것으로 인식하고 있다. 외국인 이주자를 위한 정책의 개선 방안으로, 첫째 동화주의, 차별적 배제주의, 그리고 주변화를 벗어날 수 있는 분배적 평등과 인정의 정의에 기초한 다문화주의, 둘째 지역사회에 기반을 두고 외국인 이주자 및 관련 기관과 단체들이 참여하는 외국인 이주자 네트워크 거버넌스의 구축, 셋째 지역 정체성 함양, 시민권의 보장, 종합적 복지 제공, 다문화교육 등 지속적이고 다문화주의적 내용들로 구성된 지원 프로그램의 개발 등이 제시된다.

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잔골재율 변화에 따른 콘크리트 건조수축 모델링에 관한 연구 (A Study on Modelling for Prediction of Concrete Drying Shrinkage according to Aggregate Ratio of Concrete)

  • 박도경;윤여완;김광서
    • 한국건축시공학회지
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    • 제4권4호
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    • pp.71-77
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    • 2004
  • Drying Shrinkage has much complexity as it has relations with both internal elements of concrete and external factors. Therefore, experiments on Concrete Drying Shrinkage are carried out in this study under simplified circumstances applying temperature & Humidity test chamber which enables constant temperature and humidity. Comparative analyses have been made respectively according to the consequences aiming at modelling for prediction of Concrete Drying Shrinkage and making out measures to reduce it. Strain Rate of Drying Shrinkage of concrete under the condition of dry air appears to rise by about 20%-30% in proportion as the temperature rises $5^{\circ}C$ when the humidity was held below 10% compared under the condition of dry temperature & Humidity test chamber. Strain Rate of Drying Shrinkage in pit sand concrete increased 20% higher than measured when in river sand under the condition of 90-day material age. A general formula with two variables is derived as follow ${\varepsilon}={\alpha}_1+{\beta}_1x_1+{\beta}_2x_2+{\beta}_3x_1^2+{\beta}_5x_2^2$. and also graphed in 3 dimensions, enabling to apply to actual design and predict Strain Rate of Drying Shrinkage in concrete. The results of prediction of Rate of Drying Shrinkage by Response Surface Analysis are as follows. The coefficient of correlation of Drying Shrinkage in Concrete was over 90%.

A Study on the Profitability of Private Finance Initiative Ports Companies and the Use of Old Ports Rehabilitate-Project

  • Yang, HuckJun
    • 한국항해항만학회지
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    • 제44권5호
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    • pp.430-437
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    • 2020
  • This paper analyzes the profitability of the Private Finance Initiative(PFI) ports and proposes the application plans of the R-project(Rehabilitate project) for old ports to attract and activate private investment in the port industry. The R-project of old ports can reduce the government's financial budget and provide improved facilities for users more quickly than the public sector comparator. Before suggesting the R-project for old ports, the profitability of the currently operating 11 companies of the PFI ports are analyzed using the four ratios of profitability, and the results show that all the companies indicate low profitability, except for the top three companies. To apply the R-project, the three types of R-project ports are categorized as maintaining the function of the port, changing the function of the port, and mixing the function of the port. Additionally, three obstacles and improvement measures are suggested; attracting private business, legal issues, and administrative procedures. This study is conducive to the policy making for the port renewal and the activating PFI for the port industry.

잔골재 특성에 따른 콘크리트 건조수축 모델링에 관한 연구 (A Study on Modelling for Prediction of Concrete Drying Shrinkage according to Properties of Aggregate)

  • 박도경;양극영
    • 한국건축시공학회지
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    • 제6권1호
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    • pp.73-77
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    • 2006
  • Drying Shrinkage has much complexity as it has relations with both internal elements of concrete and external factors. Therefore, experiments on Concrete Drying Shrinkage are carried out in this study under simplified circumstances applying temperature & Humidity test chamber which enables constant temperature and humidify. Comparative analyses have been made respectively according to the consequences aiming at modelling for prediction of Concrete Drying Shrinkage and making out measures to reduce it. As a result Strain Rate of Drying Shrinkage of concrete was measured to increase by average $10{\times}10^{-5}$ in proportion to additional 4% increase in fine aggregate ratio, when water/cement ratio constant. Strain Rate of Drying Shrinkage in pit sand concrete increased 20% higher than measured when in river sand under the condition of 90-day material age. 6. Strain Rate of Drying Shrinkage in sea sand concrete increased $10%{\sim}15%$ higher than measured when in river sand. The results of prediction of Rate of Drying Shrinkage by Response Surface Analysis are as fellows. The coefficient of correlation of Drying Shrinkage in concrete was over 90%.

모바일서비스의 성공 영향요인 도출과 서비스 유형별 비교분석 (Deriving the Success Factors for Retailing Mobile Services: A Comparison of Mobile Service Types)

  • 김근형;김시연
    • 한국정보통신학회논문지
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    • 제10권3호
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    • pp.586-592
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    • 2006
  • 모바일서비스는 정보시스템의 기능을 모바일 환경에서 제공하는 것이라고 할 수 있다. 따라서, 모바일서비스의 성공모형은 정보시스템의 성공모형에 모바일의 특성을 적용하여 도출될 수 있다. 다양한 모바일서비스들이 존재하고 있으며 특히, Commerce, Communication, Entertainmant, Information등은 많이 이용되고 있는 모바일서비스 유형들이다. 본 논문에서는 모바일서비스의 성공에 영향을 미치는 주요 요인들을 도출하고 서비스 유형별로 각 요인들이 어떠한 차이가 있는지를 분석해 본다.

인공위성 센서 MOPITT를 이용한 일산화탄소 모니터링: 자료처리 및 응용 (Monitoring of Carbon Monoxide using MOPITT: Data Processing and Applications)

  • 최성득;장윤석
    • 한국대기환경학회지
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    • 제22권6호
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    • pp.940-953
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    • 2006
  • The major source of carbon monoxide (CO) at the Earth's surface is the incomplete combustion of biomass and fossil fuels. Because the global lifetime of CO is about two months, it can be used as a tracer for pollution from anthropogenic activities and biomass hurtling. In this paper, we introduced the principle and algorithm of the Measurement of Pollution in the Troposphere (MOPITT) instrument for global CO monitoring. The MOPITT instrument, which was launched on the Satellite Terra in 1999, measures CO column and mixing ratio based on gas correlation radiometry. CO levels can be determined by a retrieval algorithm based on the maximum likelihood method minimizing the difference between observed and modeled radiances. MOPITT level 2 data (HDF format) can be downloaded through the Earth Observing System (EOS) data gateway of NASA. ASCII files of CO parameters can be extracted from HDF files, and then temporal and spatial distributions can be obtained. Finally, we showed an example of CO monitoring in April 2000. The locations of forest fires and distribution of MOPITT CO clearly indicated that not only anthropogenic emissions but also forest fires play an important role in CO levels and global CO distribution. Our introduction to MOPITT and the example of MOPITT data interpretation would be helpful for scientists who want to use the EOS data.