• 한국산업보건학회지
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• 제1권2호
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• pp.238-245
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• 1991

This study was analysis of ${\alpha}$-quartz in the 37 worker's lung died of coal workers' pneumoconiosis(CWP) and in the 9 normal's lung by Fourier transform infrared spectrophotometer. The results were as follows : 1. The dried lung weight percents in wet lung weight were 24.4%, 25.4%, coal workers' pneumoconiosis and normal lungs, respectively. Ash weight percents in dried lung weight were 7.7%, 5.0%, coal workers' pneumoconiosis and normal lungs, respectively. 2. The presision (as of coefficient of variation) for the ${\alpha}$-quartz determination were 2.6% in standard quartz (ranged from 9.9 to $198.0{\mu}g$) and 3.7% in ashed lung samples. 3. The characterstic ${\alpha}$-quartz absorption spectra in lungs of CWP were only shawn by LTA ashing. 4. Geometric mean of ${\alpha}$-quartz concentration in CWP lung was 173mg/100g dried lung. 5. The concentrations of ${\alpha}$-quartz in Korean CWP lungs were similar to those of foreign coal miner's lungs.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권3호
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• pp.1-10
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• 2022

Most wells developed in Jeju island before the enactment of the Groundwater Management Ordinance in 2002 are vulnerable to aquifer contamination due to inflow of upper groundwater having the high concentration of nitrate nitrogen, likely due to incomplete grouting in upper section of the wells. Although these wells require entire reinstallation, it is often necessary to rehabilitate the existing wells due to various constraints. Therefore, to identified the inflow section of contaminants, the thermal level sensor (TLS) technique was firstly applied for three wells, which enables to monitor temperature variations in every 50 cm depth. Then, the grouting material was injected to the upper section to prevent the inflow of upper contaminated groundwater into the entire aquifer. By applying TLS technique, it was found that the temperature deviations in the upper groundwater inflow section decreased sharply. Moreover, both the change in the concentration of nitrate nitrogen in the rainy/dry seasons and the average concentrations were found to decrease rapidly after grouting material injection. Consequently, the application of TLS proposed in the study turned out to be appropriate to prevent aquifer contamination.

• 대한환경공학회지
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• 제38권7호
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• pp.343-352
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• 2016

이 논문은 실험실 규모의 표면분쇄와 부유선별을 이용하여 비소로 오염된 중국 농경지 토양을 처리하기 위한 분쇄시간의 변화 및 $C_5H_{11}OCS_2K$, $Na_2S$와 $CuSO_4$의 사용량 변화에 대한 평가를 제시한다. 현장시료는 비소농도 76.51 mg/kg으로 한국과 중국의 기준치를 모두 초과하였고, 토양시료 내 비소화합물의 형태는 단계추출법에 의해 '잔류상'이 지배적인 것으로 나타났다(80% 이상). 또한 X-선 회절분석을 통하여 밝혀진 비소성분은 FeAsS, $As_4O_6$, $As_2O_5$ 화합물형태로 존재하는 것으로 확인되었다. 표면분쇄공정에 의해 원시료로부터 탈리된 입자의 비소농도는 분쇄경과시간 5분경 최대치에 달했으며, 이때의 농도는 981.66 mg/kg를 나타냈다. 비소함량이 높은 분쇄입자를 원시료로부터 선택적으로 분리하기 위해 부유선별공정에 사용된 $C_5H_{11}OCS_2K$, $Na_2S$과 $CuSO_4$의 최적 주입량은 각각 200 g/ton으로 결정되었고, 추가로 수행된 2차 부유선별인 청소부선을 통해서 침강물에서의 최대 비소제거 효율은 72.74%까지 증가하였다. 표면분쇄와 포말부선공정을 조합하여 처리된 정화토양의 입도는 >2, 0.075-2 mm와 <0.038 mm이었고, 이 정화토양의 중량분율은 각각 1.76, 18.00, 64.44 wt% 그리고, 최종정화산물의 평균 비소농도는 16.45 mg/kg로 산출되었다.

• Journal of Preventive Medicine and Public Health
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• 제20권2호
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• pp.261-269
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• 1987

In order to investigate working conditions of underground coal mines, this work was undertaken to evaluate the respirable dust and the concentration of quartz in Taeback and Kangneung areas. The concentration of quartz was determined by Fourier Transform Infrared Spectrophotometry. The results were as follows; 1) The concentration of respirable dust of drilling and coal face in Taeback and Kangneung areas were as followed; Arithmetic $Mean{\pm}S.D.(mg/m^3)$ Taeback Drilling: $2.00{\pm}1.56$ Taeback Coal Face: $3.74{\pm}3.14$ Kangneung Drilling: $4.55{\pm}4.51$ Kangneung Coal Face: $5.77{\pm}4.53$ Geometric $Mean{\pm}S.D.(mg/m^3)$ Taeback Drilling: $1.34{\pm}2.81$ Taeback Coal Face : $2.55{\pm}2.61$ Kangneung Drilling : $2.44{\pm}3.63$ Kangneung Coal Face: $4.24{\pm}2.37$ 2) Distribution of respirable dust was well fitted to the log-normal distribution and geometric mean value was $log^{-1}\;0.37{\pm}log^{-1}\;0.47(2.34{\pm}2.95)mg/m^3$. 3) The difference of respirable dust concentrations in Taeback and Kangneung areas was not significant statistically (p>0.05). 4) The concentration of quartz of drilling and coal face in Taeback and Kangneung areas were as followed; Arithmetic $Mean{\pm}S.D.(%)$ Taeback Drilling: $6.18{\pm}5.52$ Taeback Coal Face: $1.89{\pm}1.54$ Kangneung Drilling: $3.54{\pm}2.12$ Kangneung Coal Face: $2.05{\pm}3.37$ Geometric $Mean{\pm}S.D.(%)$ Taeback Drilling: $4.24{\pm}2.59$ Coal Face: $1.39{\pm}2.22$ Kangneung Drilling : $2.55{\pm}3.08$ Kangneung Coal Face : $1.24{\pm}2.33$ 5) Distribution of quartz concentrations was well fitted to the log-normal distribution and geometric mean value was $log^{-1}\;0.33{\pm}log^{-1}\;0.45(2.14{\pm}2.82)%$. 6) The difference of quartz concentrations in Taeback and Kangneung areas was not significant (p>0.05), but significant at drilling sites and coal faces (p<0.05).

• 한국환경과학회지
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• 제20권10호
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• pp.1233-1241
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• 2011

The main objective of this experimental investigation was $CH_4$ recovery from biogas generated in municipal and wastewater treatment plant. The polysulfone hollow fiber membrane was prepared in order to investigate the permeation properties of $CH_4$ and $CO_2$. Permeability of $CO_2$ in Polysulfone membrane was 11-fold higher than of $CH_4$ gas. A membrane pilot plant for upgrading biogas was constructed and operated at a municipal wastewater treatment plant. The raw biogas contained 66 ~ 68 Vol % $CH_4$, the balance being mainly $CO_2$. The effect of the operating pressure of feed and permeate side and feed flowrate on $CH_4$ recovery concentration and efficiency were investigated with double stage membrane pilot plant. The $CH_4$ concentration in the retentate stream was raised in these tests to 93 Vol % $CH_4$.

• 한국산업보건학회지
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• 제1권2호
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• pp.154-163
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• 1991

Particulate matter exposure leva1 of welders and grinding workers was evaluated in Banwol and Changwon industry complexes. Full period single sample and full period consecutive samples were collected with personal air samplers attached to workers. Compliance difference with 8-hour time weighted average (TWA) was compared by Korean strategy and the classification system recommended by OHSA for employee exposure to particulates. And difference of compliance was compared according to precision of measurement and analysis (total precision). Compliance rate was depended on the total precision, therefore, quality control of measurement and analysis was important.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.113-114
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• 2017

Recently, Subway workers have died from lung cancer. According to the Epidemiological Survey of the Welfare Corporation Institute of Pulmonary Disease of the Welfare Corporation, the family members applied for industrial accidents. The radon concentration in the subway work area was found to exceed 10 times the recommended standard value of 148 becquerels (Bq/㎥) in domestic multipurpose facilities. In addition, as a result of the national indoor radon concentration survey conducted by the Ministry of Environment in 2010 and 2013, housing was found to be over 100 becquerels (Bq/㎥) in 41% of the surveyed subjects. In addition, it was found that in 2012, 16.3% of villages exceeded the radon standard value in the survey on natural radioactive materials containing groundwater.

• Journal of Electrical Engineering and Technology
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• 제7권3호
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• pp.342-348
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• 2012

This paper presents a moving-magnet type linear actuator designed by using flux concentration type permanent magnet arrangement, which can generate higher magnetic flux density in air-gap. In this construction, detent force which is induced by both slot-effect and end-effect becomes larger due to strong attractive forces. To reduce cogging force we have employed a modular mover structure of two magnetic pole sections connected with a center yoke. The improved motor performance is demonstrated with the prototype machine.

• 한국산업보건학회지
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• 제5권1호
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• pp.40-47
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• 1995

We analyzed sytrene concentrations in air and in blood, mandelic acid in urine, and chromosome aberrations in peripheral lymphocytes of twenty one styrene-exposed workers in two reinforced plastic factories. In addition, in vitro testing for chromosome aberration was carried out. The dose-dependent clastogenicity of styrene was confirmed in the cultured Chinese hamster lung cell(CHL) with metabolic activation. The environmental styrene concentrations and urinary mandelic acid levels of analyzed subjects were different in two plants examined, but the exposure levels in most workers examined were lower than the permissible exposure levels. Chromosome aberrations of the styrene exposed workers showed no increase in the percentage of aberrant cells as compared with the control group. No correlation was found between the exposure levels and the frequencies of chromosome aberrations in workers.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권3호
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• pp.32-38
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• 2012

This study was conducted to evaluate the slurping process affecting the variation of free product and VOCs concentration and the bioaugmentation effect on bioremediation process. Free products and soil gas were extracted from 30 extraction wells installed in a petroleum contaminated area. The extraction system was operated for 10 hours per day with 1 hour on-and-off mode. The thickness of free product in extraction well was decreased from 11.7 cm to 4.5 cm and the VOCs concentration was increased from 10.37 ppm to 30.78 ppm during the operation period. After the slurping process for 2 months, contaminated soil was treated with bioremediation process in 2 cells, $15{\times}40$ m, biologically enhanced with adjusting oxygen, moisture and nutrients concentration. Total 1,400 L of microbial inoculant, Naturesys. (Dong Myung Ent. Co.) was added to the pile B, which has an outstanding ability for degrading petroleum hydrocarbons. The results showed that bioremediaton effect in soil with the microorganisms solution is 33% higher than that in soil with only residual bacteria.