• 한국건설관리학회논문집
• /
• 제3권4호
• /
• pp.93-103
• /
• 2002

철근공사는 거푸집공사와 더불어 건축물의 구조적 안정성과 내구성 및 공기에 가장 큰 영향을 미치고 있는 공사이다. 그러나 국내 철근 콘크리트 공사는 철근현장가공조립을 주로 하고있어 낮은 생산성을 갖고 있는 실정이다. 따라서 본 논문은 생산성 향상을 위해 철근현장가공조립 프로세스를 부가가치 생산성향상을 위한 낭비요소를 분석하였다. 낭비요소 분석은 비가치창출 작업으로 인해 발생하는 요소로 철근현장가공조립의 가치분석을 통해 부가가치를 극대화 하고자 하였다. 그 결과 가치창출작업들이 비가치창출 작업보다 월등히 적다는 것으로 분석되었다. 특히, 본 논문에서 낭비는 불필요한 작업 단계와 인력, 장비, 자재, 시간 등에서 낭비되고 있었다. 또한 흐름생산이 되지 않고, 과잉생산을 하고 있는 것으로 조사되었으며, 가치의 변화가 필요한 것으로 분석되었다. 본 논문에서는 부가가치 생산성 향상을 위해 프로세스 상에 내재되어 있는 낭비요소를 분석하여 부가가치를 창출하는 가치창출 작업을 최대화하고, 비 가치창출작업을 최소화하는데 목적이 있다.

• 방사성폐기물학회지
• /
• 제13권1호
• /
• pp.63-72
• /
• 2015

우리나라의 중·저준위 방사성폐기물은 월성환경관리센터를 이용하여 처분된다. 처분시설의 안전성을 확인하기 위하여 자연현상에 의한 시나리오뿐만 아니라 인간침입에 의한 시나리오도 고려하여 평가한다. 인간침입 시나리오는 제도적관리기간 이후 처분시설의 존재를 모르는 인간에 의해 시추 등과 같은 행위로 인해 일어나는 시나리오로서, 우물이용 시나리오는 처분부지 내 우물의 시추확률이 수십 년 생애기간에 시나리오에 의한 피폭을 한번이라도 경험할 수 있는 가능성이 낮음을 보여 인간침입 사건범주로 구분하였으며, 보수적인 가정을 사용하여 평가하였다. 이를 위하여 우물의 위치 및 처분시설로부터 누출된 오염물질의 우물 유입비율을 지하수 유동 모델링을 통하여 계산되었으며, 이에 대한 방법론을 소개하였다. 또한, 이 방법론을 핵종이동 모델링에 적용하여 처분시설에 미치는 영향을 평가하여, 평가된 시나리오는 성능목표치를 만족하고 있음을 보였다.

• Structural Engineering and Mechanics
• /
• 제89권3호
• /
• pp.253-263
• /
• 2024

Slope stability is generally paid more attention to in slope protection works, especially for slope containing weak layers. Two indexes of safety factor and failure model are selected to perform slope stability. Moreover, the finite element limit analysis method comprehensively combines the advantage of the limit analysis method and the finite element method obtaining the upper and lower bounds of the safety factor and the failure mode under the slope stability limit state. In this study, taking a waste dump containing a weak layer as an engineering background, the finite element limit analysis method is adopted to explore the potential failure mode. Meanwhile, the sensitivity analysis of slope stability is performed on geometrical and geotechnical parameters of the waste dump. The results show that the failure mode of the waste dump slope is two wedges if the weak layer is located on the ground surface (Model A), while the slope can be observed as three wedges failure if the weak layer is below the ground surface (Model B). In addition, both failure modes are highly sensitive to the friction angle of the weak layer and the shear strength of waste disposal, and moderately sensitive to the heap height, the dip angle and cohesion of the weak layer, while the toe cutting has limited effect on the slope stability. Moreover, the sensitivity to the excavation of the ground depends on the location of the weak layer and failure mode.

• Environmental Analysis Health and Toxicology
• /
• 제31권
• /
• pp.6.1-6.10
• /
• 2016

Objectives This study examined the spatial distribution and the extent of soil contamination by heavy metals resulting from primitive, unconventional informal electronic waste recycling in the Agbogbloshie e-waste processing site (AEPS) in Ghana. Methods A total of 132 samples were collected at 100 m intervals, with a handheld global position system used in taking the location data of the soil sample points. Observing all procedural and quality assurance measures, the samples were analyzed for barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn), using X-ray fluorescence. Using environmental risk indices of contamination factor and degree of contamination ($C_{deg}$), we analyzed the individual contribution of each heavy metal contamination and the overall $C_{deg}$. We further used geostatistical techniques of spatial autocorrelation and variability to examine spatial distribution and extent of heavy metal contamination. Results Results from soil analysis showed that heavy metal concentrations were significantly higher than the Canadian Environmental Protection Agency and Dutch environmental standards. In an increasing order, Pb>Cd>Hg>Cu>Zn>Cr>Co>Ba>Ni contributed significantly to the overall $C_{deg}$. Contamination was highest in the main working areas of burning and dismantling sites, indicating the influence of recycling activities. Geostatistical analysis also revealed that heavy metal contamination spreads beyond the main working areas to residential, recreational, farming, and commercial areas. Conclusions Our results show that the studied heavy metals are ubiquitous within AEPS and the significantly high concentration of these metals reflect the contamination factor and $C_{deg}$, indicating soil contamination in AEPS with the nine heavy metals studied.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2003년도 가을 학술논문집
• /
• pp.534-538
• /
• 2003

Final disposal of radioactive waste generated from Nuclear Power Plant (NPP) requires the detailed knowledge of the natures and quantities of radionuclides in waste package. Many of these radionuclides are difficult to measure and expensive to assay. Thus it is suggested to the Indirect method by which the concentrations of DTM (Difficult-to-Measure) nuclide is decided using the relation of concentrations (Scaling Factor) between Key (Easy-to-Measure) nuclide and DTM nuclide with measured concentrations of Key nuclide. In general, scaling factor is determined by using of log mean average (LMA) and regression. These methods are adequate to apply most corrosion product nuclides. But in case of fission product nuclides and some corrosion product nuclides, the predicted values aren't well matched with the original values. In this study, the models using artificial neural network (ANN) for C-14 and Sr-90 are compared with those using LMA and regression. The assessment of models is executed in the two parts divided by a training part and a validation part. For all of two nuclides in the training part, the predicted values using ANN are well matched with the measured values compared with those using LMA and regression. In the validation part, the accuracy of the predicted values using ANN is better than that using LMA and is similar to or better than that using regression. It is concluded that the predicted values using ANN model are better than those using conventional model in some nuclides and ANN model can be used as the complement of LMA and regression model.

• 한국지리정보학회지
• /
• 제3권4호
• /
• pp.33-49
• /
• 2000

본 논문은 도시지역의 폐기물 매립지의 적지선정에 GIS기법을 적용한 사례연구를 제시한 것이다. 폐기물 매립지의 적지분석을 위한 여러 가지 평가인자들을 결정하고 데이터의 수집, 입력, 변환을 통하여 데이터베이스가 구축되었다. 또한 위성영상의 처리에 의해 대상지역의 최근 토지피복 분류와 식생활력도(NDVI) 데이터가 평가인자로서 GIS데이터에 통합되었다. 사회경제적 인자와 자연환경적 인자로 구분되는 1차 분류 평가인자들의 가중치를 이원비교법에 의해 결정된 2차분류 평가인자들의 가중치와 조합하여 분석하였다. 사례연구의 결과, 여러 가지 평가기준에 따른 적합성 분석이 가능하였으며, 사회경제적 인자를 중요하게 간주하는 관점에서 2차 분류 평가인자들의 가중치를 중요도에 따라 다르게 부여한 경우에서 가장 높은 적합도가 얻어졌다.

• 한국폐기물자원순환학회지
• /
• 제35권8호
• /
• pp.770-776
• /
• 2018

This study measured the energy recovery rate of each municipal waste incineration facility according to the revised energy recovery rate estimation method, which targeted four municipal waste incineration facilities (Unit No. 7). The results calculated by the measuring instruments were used for each factor to estimate the recovery rate, and the available potential of available energy was examined by analyzing the energy production and valid consumption. As a result of the low heating value, 2,540 kcal/kg was calculated on average when the LHVw formula was applied, which is approximately 116 kcal/kg higher than the average design standard of 2,424 kcal/kg. The energy recovery rate was calculated as 96.9% on average based on production and 67.5% based on effective consumption, and the analysis shows that approximately 29.4% energy can be used.

• 한국연초학회지
• /
• 제21권2호
• /
• pp.136-143
• /
• 1999

This study was conducted to evaluate the degradation characteristics of waste cigarette filters under 0, 5, 10, and 15cm in depth from soil surface by environmental conditions. Weather was the most important factor during degradation of waste cigarette filters in this study. Bulking of cellulose acetate filaments exposed on soil surface was observed after 2 months, but the form of filter was kept up after 12 months. The treated cigarette filters in soil landfill revealed a little different degradation pattern at each soil landfill depth, The sample in 5cm depth of soil was more degraded then other site. A fluffy appearance of cellulose acetate filaments in the control filter rods was also developed more strongly in soil landfill then on soil surface. From the observation of waste cigarette filters by scanning electron microscopy, much degradation of the fiber of waste cigarette filters could be ascertained in soil landfill. The weight of waste cigarette filters under 5cm from soil surface was reduced about 50%, and the tensile strength of the samples in soil surface and under 5cm from soil surface were reduced 66.0% and 92.4%, respectively. The microbial experiment date that the viable cell number in microbial population and cellulolytic microorganisms showed the maximum values under 5cm from soil surface, suggest that microorganisms in soil play an important roll in the degradation of acetate cigarette filters.

• 대한영양사협회학술지
• /
• 제7권4호
• /
• pp.410-425
• /
• 2001

This study was designed to assess the waste management practices, source-reduction programs and related tasks in elementary school foodservice in Seoul. and Kyonggi Province Areas. A questionnaire mailed to 910 school foodservice managers in Seoul and Kyonggi province: a 202% (N=184) response rate was obtained. About 83.7% of school foodservice managers were responsible for managing solid waste. Most foodservice operations take the responsibility of food waste but not packaging wastes. The average disposal cost per month per person was about 19 won and income was about 35 won. Leftovers were mainly disposed with platewaste. Platewaste was reused for the livestook feed(68.0%), and some platewaste was composted(11.6%). Source reduction programs implemented in half of school foodservice operations were adjustment of portion size', checking the plate waste', 'working with classroom teachers on waste reduction campaign', 'providing information leaflet on food waste minimization', posting education materials, 'classroom instruction about food waste minimization', and 'improving cooking method. According to factor analysis based on importance rating. slid waste management activities of elementary school foodservice operations were divided to 7 dimensions such as communication and cooperation with others', 'employee training', 'product quality control, 'yield control', plate waste control', 'purchasing', and 'public relations'. As a result of Important-Performance Analysis(IPA), sine dimensions such as 'communication and cooperation with others' and 'plate waste control were identified in Focus Here' quardrant area which need more enhanced performance.

• 한국지반환경공학회 논문집
• /
• 제3권1호
• /
• pp.5-12
• /
• 2002

본 연구에서는 지하수위, 폐기물의 전단강도 정수 그리고 지층 조건이 비위생 매립지 사면의 안정성에 미치는 영향을 검토하였다. 사면의 안정성 해석은 한계평형방법에 근거한 Janbu의 절편법을 사용하였다. 해석 결과 매립지가 완전건조 상태에 있는 경우가 완전포화 상태에 있는 경우에 비해 안전율이 약 2.4~2.8배 정도 증가되었다. 관측된 지하수위 상태 하에서 폐기물의 점착력과 내부마찰각이 증가할수록 사면의 안전율은 선형적으로 증가하였으며, 예상파괴면이 하부지층까지 도달할 경우 하부지층의 조건에 따라 안전율과 예상 파괴면의 형상이 변화한다는 것을 알 수 있었다. 따라서, 폐기물 매립지 건설 시에는 지반조건이 양호한 지반을 선택하고, 지하수위 감소를 위한 차수 및 배수 시스템을 설치하는 것이 사면의 안정성 향상에 도움을 줄 것으로 판단된다.