• 한국환경과학회지
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• 제27권1호
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• pp.1-10
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• 2018

A continuous process of persulfate oxidation and citric acid washing was investigated for ex-situ remediation of complex contaminated soil containing total recoverable petroleum hydrocarbons (TRPHs) and heavy metals (Cu, Pb, and Zn). The batch experiment results showed that TRPHs could be degraded by $Fe^{2+}$ activated persulfate oxidation and that heavy metals could be removed by washing with citric acid. For efficient remediation of the complex contaminated soil, two-stage and three-stage processes were evaluated. Removal efficiency of the two-stage process (persulfate oxidation - citric acid washing) was 83% for TRPHs and 49%, 53%, 24% for Cu, Zn, and Pb, respectively. To improve the removal efficiency, a three-stage process was also tested; case A) water washing - persulfate oxidation - citirc acid washing and case B) persulfate oxidation - citric acid washing (1) - citric acid washing (2). In case A, 63% of TRPHs, 73% of Cu, 60% of Zn, and 55% of Pb were removed, while the removal efficiencies of TRPHs, Cu, Pb, and Zn were 24%, 68%, 62%, and 59% in case B, respectively. The results indicated that case A was better than case B. The three-stage process was more effective than the two-stage process for the remediation of complex-contaminated soil in therms of overall removal efficiency.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권4호
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• pp.45-51
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• 2014

In accordance with the view on remediated soil as a resource, this study assessed the applicability of soil washing with the neutral phosphate for remediation of arsenic (As)-contaminated soil. Three soil samples of different land uses (i.e., rice paddy, upland field and forest land) were collected from the study site, and the aqua regia-extractable As concentrations were 59.2, 30.8 and 53.1 mg/kg, respectively. Among the neutral phosphate reagents, ammonium phosphate showed the highest As washing efficiency. The optimized washing condition was 2-hr washing with 0.5M ammonium phosphate solution (pH 6) and soil to liquid ratio of 1 : 5. The extraction efficiencies of As did not guarantee the residual soil As concentrations to satisfy the Korea soil regulatory level (i.e., Worrisome level) in the three soil samples. To enhance washing efficiency, the As-contaminated soil was submerged in washing solution (1 : 1, w/v) for 24 hr and 1-hr washing with 0.5M ammonium phosphate solution was tested. As extraction efficiencies of 36.1 (rice paddy), 21.4 (upland field) and 26.4% (forest land) were attained, which satisfied the Worrisome level for Region 1 (25 mg/kg of As) in rice paddy, but not in upland field and forest land.

• 산업식품공학
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• 제14권4호
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• pp.316-321
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• 2010

본 연구는 식중독을 일으키는 병원성 미생물들은 식품시료와 교차오염 원인의 지표가 될 수 있는 도마에 접종한 후 오존수와 일반 수돗물을 이용하여 세척한 후 미생물의 변화와 세척방법에 따른미생물의 변화를 각각 비교 관찰하였다. 실험결과 일반 수돗물보다 오존수가 살균효과가 더 높았고, 같은 세척수로 세척 시에도 접종 방법, 실험시료 및 시료의 표면, 균질화에 따라 살균효과가 다르게 나타나는 것을 확인할 수 있었다. 세척방법으로는 침수보다 주수 에서 살균효과가 더 컸으며 오존수의 농도는 0.2 ppm에서 유의적인 살균효과를 나타내었으며 오존수 농도가 0.4, 0.6, 1.0 ppm으로 증가함에 따라 농도 의존적으로 살균효과 또한 증가하였다. 위의 결과들을 통해 0.2 ppm 이상의 오존수가 부패 미생물 제어에 미치는 영향이 크고 식품의 제조 가공 시 여러 안전성 면에 있어서 오존수를 이용한 세척이 효과적이라고 생각된다.

• 한국식품위생안전성학회지
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• 제24권2호
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• pp.182-187
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• 2009

작물을 데치거나 국을 끓여 먹는 과정에서의 잔류농약 경감을 조사하기 위해 비닐하우스에서 재배하면서 농약을 살포한 시금치 (bifenthrin, metalaxyl, procymidone), 근대(bifenthrin, imidacloprid), 아욱(bifenthrin, chlorpyrifos, imidacloprid)을 세척하고 물에 넣고 끓여(시금치: 1분, 3분, 5분, 근대: 3분, 6분, 9분, 아욱: 10분, 20분, 30분) 잔류농약 제거율을 조사하였다. Bifenthrin, procymidone은 세척에 의해 각각 $58{\sim}64%$, 82%제거되었고 끓임에 의해 제거율이 유효하게 변하지 않았다. Imidacloprid의 경우 근대에서 43%, 아욱에서 12%가 세척에 의해 제거되었으며 끓임에 의해 94%까지 크게 제거되었다. Metalaxyl, chlorpyrifos는 세척에 의해 각각 69%, 11%가 제거되었고 끓임에 의해 98%, 79%까지 유효하게 제거되었다. 한편 국을 끓여 먹을 때를 고려하여 끓이는 과정에서 사용된 물과 작물체를 합하여 제거율을 조사했을 때는 아욱의 imidacloprid와 chloropyrifos만이 끓임에 의해 효과적으로 제거되었고($12%{\rightarrow}34{\sim}40%$, $11%{\rightarrow}76{\sim}78%$) 다른 농약들은 세척과 차이가 없었다. 이러한 농약들은 작물체를 물에서 끓이는 과정에서 물로 이동되었으나 끓임에 의해 제거되지 않고 물속에 남아 있는 것으로 판단되었다.

• 한국식품위생안전성학회지
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• 제25권4호
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• pp.346-353
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• 2010

본 연구는 젖소 착유농가를 대상으로 착유 및 집유 후 친환경세제를 사용하여 세척효과에 미치는 영향을 조사하기 위해 수행되었다. 착유환경이 다른 5지역의 농가를 대상으로 총 시험 기간 6주 동안 첫 3주는 기존 관행세제인 알칼리 세제와 산세제를 사용하여 착유기, 냉각기 및 착유기 라이너를 세척하였으며, 처리를 달리하여 3주는 알칼리 세제와 친환경세제를 사용하여 세척 하였다. 또한 착유기 라이너 내부를 멸균된 swab을 이용해 시계방향으로 10회 닦은 후 0.1% peptone수에 보관하였으며, 채취된 모든 샘플은 아이스박스를 이용해 보관 운반하여 잔류세균 및 잔류물질 분석을 실시하였다. 미생물 분포는 모든 지역의 착유농가에서 대장균, 대장균군, 황색포도상구균, 분내 대장균군, 녹농균 및 여시니아균이 발견되지 않았으며, 총균수는 관행세제 사용과 비교하여 차이가 없었다. 따라서 친환경세제의 세척효과는 관행세제와 비교하여 비슷한 세척효과를 나타낸 것으로 조사되었다. 세척수 잔류물질은 안성, 온양 및 천안의 젖소 착유농가의 세척수로 사용한 용수에서 질산성 질소가 기준치를 초과하였으며, 세척수의 잔류물질에서도 높은 농도를 나타냈다. 특히 원유의 특이취와 밀접한 관계가 있는 음이온계면활성제의 농도는 관행세제를 사용한 오수와 남원지역의 세척수에서 기준치보다 높은 농도를 나타냈으며, 친환경세제 사용 처리구에서는 기준치보다 낮은 결과를 나타냈다. 따라서 본 연구에서는 친환경 세제를 젖소 착유농가의 착유기 및 냉각기의 세척제로 사용하였을 때, 관행세제와 비교하여 세척효과가 비슷한 것으로 조사됐다. 또한 세척제 사용뿐만 아니라, 위생적인 착유장비 및 세척에 사용되는 용수 관리가 고품질 원유생산에 중요한 영향을 줄 것으로 생각된다.

• Agricultural and Biosystems Engineering
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• 제5권2호
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• pp.60-63
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• 2004

Demand for development of processing systems for pre-washed rice and propagation of the systems has recently been on the rise, because rice-cooking requires watering 15 times the rice quantity to cook, as in case of the regular rice currently being circulated in Korean market, in addition to paying the trouble of washing it for cooking, and besides the milky turbid water coming from the rice-washing contributes to water contamination. In this study, therefore, a processing system for pre-washed rice was designed and built with rice surface polishing devices that adopted abrading and airing methods, an electrostatic method and a method using a fine watering, to conduct its performance test. The result showed that turbidity of the wash water, which is the base to determine the pre-washed rice standard, turned out 47.33 ppm and 48.00 ppm respectively for 800 kg/hr and 1,000 kg/hr supplies, which meets the standard for the processing system free from rice-washing for cooking. The quantity of watering at this experiment was only 0.43 times the rice, thus resulting in curtailment of process-watering by approximately $69\%$ compared with the existing wet-type pre-washed rice processing system popular in Korean market.

• 치위생과학회지
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• 제22권1호
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• pp.51-56
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• 2022

Background: The coronavirus disease (COVID-19) pandemic increased awareness regarding the importance of hand hygiene in infection prevention. Although social distancing and vaccination are the strongest ways to prevent infection, personal hand hygiene is the most basic and easiest way to maintain public health. However, in addition to hand washing using running water, sanitizing tissues, and disinfection products are convenient for hand hygiene, especially outdoors. Therefore, it is necessary to improve the appropriateness of individual hand hygiene methods. In this study, we investigated the degree of hand hygiene offered by various hygiene products and hand drying methods for maintaining hand hygiene. Methods: An LED UV light kit was used for fluorescent observation of hand contamination. Bacteria from the hands were cultured to compare the degree of hand hygiene offered by various hygiene products. Bacteria were cultured in a hand-shaped medium dish to identify areas vulnerable to hand hygiene. Moreover, the degree of hand hygiene was observed according to the drying method using bacterial cultures. Results: We confirmed that hand washing under running water with antibacterial soap, sanitizing with alcohol gel disinfectant, and wiping with antibacterial wet wipes was effective for hand hygiene compared to washing under running water alone. However, for all hygiene products, a large number of bacteria were detected on the fingertips. We verified that natural drying, rather than rubbing, is effective in maintaining hand hygiene. Conclusion: These results suggest that hand hygiene products and drying methods are critical in hand hygiene management. Therefore, these results provide a basis for determining whether an individual's hand hygiene management method is appropriate.

• 한국식품과학회지
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• 제31권6호
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• pp.1511-1517
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• 1999

$5^{\circ}C$로 냉각한 전해산화수를 사용, 상치를 대상으로 하여 침지, 분사, 유수 및 다단침지법에 따른 세척방법별 살균효과 및 저장중 품질변화를 조사한 결과, 세척방법에 따른 미생물 살균효과는 전해산화수로 2분간 3회 처리한 다단 침지방식이 가장 우수하였으며, 2분간 3회 처리한 다단 침지방식으로 처리한 후 포장하여 $10^{\circ}$ 저장시의 품질변화에 있어서는, 초기 총균수는 전해산화수 처리구가 무처리구 및 수도수 처리구에 비해 각각 1/300 및 1/100정도 낮았고, 대장균군수도 침지 초기에는 전해산화수 처리구가 $3.1{\times}10^3CFU/g$으로 무처리구의 1/3,000 수준으로 매우 낮게 나타났으나 저장 3일 후부터는 무처리구와 유사한 수준이었다. 저장중의 색도변화는 전해산화수 처리구가 무처리 및 수돗물 처리구에 비해 L 및 b값이 다소 높게 나타났으며, 클로로필 함량은 초기에 무처리구보다 9% 적은 값을 나타내었으나 저장기간이 경과하면서 무처리구와 거의 같은 수준으로 감소하였다. 폐기율은 저장 6일까지 전해산화수로 침지한 상치가 가장 낮게 나타났으며, 종합적 기호도는 저장 3일까지, 외관적 품질은 저장 6일까지 전해산화수 처리구가 무처리구보다 좋은 것으로 나타났다.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권2호
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• pp.148-154
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• 2014

This paper describes problems of the sensorless starting of horizontal axis washing machines with direct drive and suggests solution, which was experimentally verified. Horizontal axis washing machines have very difficult conditions for the drive starting, especially at full load. Inertia of the tub and water, torque from the laundry make load torque at starting higher than rated one and sometimes even higher than the maximum torque of the motor, which makes sensorless starting extremely challenging task. This paper suggests modified open-loop starting, where control system is closed shortly after beginning at low speed and rotates the drum until laundry restructuring. To ensure proper work of the sensorless algorithm at low speed additional measures for increasing of the estimation algorithm performance have been taken. These measures include special algorithm for the drive parameters estimation, which has been developed and verified by the experimental results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.296-300
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• 2001

In order to recycle the incineration ash (bottom ash and fly ash) generated from the incineration of municipal waste for a cement material, salts as well as heavy metal should be removed by the stabilization treatment. Most of these heavy metal and over 80% of salts are removed by a washing as a pre-treatment. However, wastewater which is another pollutant is generated by a washing, then proper treatment should be developed. First the characteristics of incineration ashes collected from two domestic full-sized incinerators were investigated and removal rate of salts and heavy metals from them also studied. The wastewater quality was compared to the criteria of the regulation by analyzing the characteristics of generated wastewater during the washing of incineration ash as a condition of liquid/solid ratio. Also, we tried to used this experimental results for the basic data to develop proper processing technique of municipal waste.