• 환경위생공학
• /
• 제12권2호
• /
• pp.65-74
• /
• 1997

The purpose of this study was to investigate the removal effect and variation of contaminated water by various water treatment processes using sediment filter, activated carbon, photocatalysis, reverse osmosis, ultra violet sterilizer and ultra filtration. The removal effect of chloride and trace metal was low by activated carbon and ultra filter but high in reverse osmosis. The removal effect of bacteria and E. coli was low by activated carbon and membrane filter system using activated carbon but high in impregnated activated carbon. The removal effect of TCE was low in sand and ultra filter system as compared with activated carbon. Ultra filtration process was effective for purify agricultural water without E.coli. Reverse osmosis was effective to remove heavy metal and activated carbon was effective to remove halogenated organic chemical compound. The flux and the removal effect of COD in spiral wound ultrafilter were higher than the hollow fiber ultrafilter.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2006년도 하계학술발표대회 논문집
• /
• pp.429-435
• /
• 2006

In this study multi-zone modeling program CONTAM 2.4 which is developed by NIST is used for modeling the air disinfection system which is consist of dilution, filtration, ultra violet germicidal irradiation (UVGI) for removing the indoor microorganism such as bacteria and fungus. Developed models those protect occupants against indoor microorganism generated in our daily life are enable to use for immune building simulation tool. Also, results indicate that those models are enable to compute the real situation that is almost impossible of carrying out experiment and identify the disinfection rate with highly reliance. Results also suggest that engineers will use these models as a design tool for the immune building system.

• 한국식품과학회지
• /
• 제41권6호
• /
• pp.652-656
• /
• 2009

탁주를 효과적으로 살균하기 위해서 110가닥의 테프론 튜브와 9개의 자외선(UV) 램프(1,335W)로 구성된 허니컴방식의 UV 살균기를 제작하고 탁주를 순환시켜 살균하여 미생물 살균효과 및 저장 중의 품질변화를 평가하였다. 허니컴방식의 UV 살균기에서 유속 2 L/min에서 4분 동안 탁주를 순환시킨 조건은, 일반세균 및 진균을 2-3 log cycle 감소시키면서 관능적으로 양호한 품질을 얻을 수 있는 최적의 살균조건으로 판단되었다. 이 조건에서 살균 처리한 탁주를 $30^{\circ}C$에서 8일간 저장하면서 pH, 아미노태질소 함량, 환원당 함량, 산도, 그리고 일반세균수 및 진균수의 변화를 측정하였다. pH, 산도, 아미노태 질소 함량은 저장 중에 생탁주와 UV 살균탁주에서 모두 증가하는 경향을 나타낸 반면 환원당 함량은 감소하는 경향을 나타내었다. 또한 생탁주와 UV살균탁주의 L, a, b 값은 저장 중에 매우 유사한 경향을 나타내었다. 저장 중에 UV 살균탁주의 진균은 생육이 억제되었으며 일반세균은 저장 4일째에 생탁주 수준에 도달하였다.

• Restorative Dentistry and Endodontics
• /
• 제24권1호
• /
• pp.222-232
• /
• 1999

The purpose of this study was to evaluate the effect of heated spreader on the sealing ability of lateral condensation, compared with regular cold spreader. Forty two extracted human teeth with single canal were randomly placed into 3 experimental groups, and four additional teeth were used as positive and negative controls. Each group was prepared with Ni-Ti Profile #40 using step-down technique and obturated with standardized colored gutta-percha cone by standard(cold) lateral condensation technique, warm lateral condensation technique with Endotec and hot spreader soaked in glass bead sterilizer, each with Sealapex sealer. Control groups were not obturated, but prepared. After 2 days in 2% methylene blue, the teeth were invested and made into transparent resin blocks. And then, each block was sectioned horizontally with microtome at 1, 2, 3, 4, 5 mm levels from the apex. The linear extent of dye penetration was examined with stereomicroscope at ${\times}$20 magnification. At each of 5 levels, ratio of the area of gutta-percha was obtained by calculating the area of gutta-percha to the total area of the canal. The data collected were then analyzed statistically using an analysis of variance(ANOVA) and Scheffe test. The results were as follows ; 1. All experimental groups produced the apical microleakage. 2. The mean leakage was 1.57${\pm}$0.76mm for cold spreader group, 0.86${\pm}$0.95mm for Endotec spreader group, and 0.64${\pm}$0.93mm for hot spreader group. The difference between hot spreader group and cold spreader group was statistically significant(p<0.05). 1. At the 1 mm level, the mean ratio of area of gutta-percha was 74.58${\pm}$13.15(%) for cold spreader group, 65.42${\pm}$14.62(%) for Endotec spreader group, and 80.72${\pm}$14.63(%) for hot spreader group. There was statistically significant difference between hot spreader group and Endotec spreader group(p<0.05). 2. At the 2mm level, the mean ratio of area of gutta-percha was 87.86${\pm}$11.22(%) for cold spreader group, 66.55${\pm}$14.02(%) for Endotec spreader group, and 92.93${\pm}$7.24(%) for hot spreader group. There was statistically significant difference between Endotec spreader group and other two spreader groups(p<0.05). 3. At the level 3, 4, 5 mm, there was no statistically significant difference between each group. Within the limits of the results of this experiment, warm lateral condensation technique with hot spreader soaked in a glass bead sterilizer demonstrated favorable apical sealing effect and improved density of gutta-percha mass. Thus, it is thought that this obturation technique is effective for clinical use and beneficial to reduce condensation forces, also economical and easy. Lateral condensation, Heated spreader, canal sealing, Microleakage.

• 한국방사선학회논문지
• /
• 제16권3호
• /
• pp.195-201
• /
• 2022

초음파 검사는 프로브를 직접 수검자의 몸에 접촉하여 검사하는 방법으로 이에 따른 적절한 소독법이 필요하다. 특히 인체 내 점막과 접촉하는 직장/질 초음파 프로브의 경우 글루타알데히드(glutaraldehyde) 2% 용액에 20분 침지 또는 과산화수소수(H₂O₂) 7.5% 용액에 30분간 침지 등 높은 수준의 소독을 진행해야 한다. 이에 본 연구에서 단시간에 높은 수준의 소독을 진행할 수 있는 증기훈증 방식을 이용한 소독기의 사용 가능성을 평가하였다. 임상에서 사용되는 프로브를 균 채취용 면봉으로 스미어하여 세균을 검출하였고 기존의 7.5% 과산화수소수(H₂O₂)보다 높은 농도인 35% 과산화수소수(H₂O₂)를 사용하여 시간 대비 소독력을 비교하였다. 고농도의 과산화수소수(H₂O₂)에 의한 프로브 러버의 손상 여부를 판단하기 위하여 35% 과산화수소수(H₂O₂)에 85시간 10분 침지 후 프로브 러버의 경도와 표면 변화를 분석 의뢰하였고 소독력 평가를 위하여 증기훈증 방식을 이용한 소독기에 5분간 소독하여 세균 사멸 효과를 평가하였다. 프로브 러버에서 검출된 세균을 이용하여 시간에 따른 소독력을 비교 평가하였을 때 과산화수소수(H₂O₂) 7.5% 용액에 비해 과산화수소수(H₂O₂) 35% 용액이 더 세균 사멸 효과가 좋았다(p<0.05). 35% 과산화수소수(H₂O₂)에 침지한 프로브 러버의 경도와 표면 변화를 관찰한 결과 큰 변화가 없었다. 증기훈증방식을 이용한 소독기에 검출된 세균을 도포하고 5분간 소독한 결과 100% 사멸 효과가 나타났다. 이에 증기훈증 방식을 이용한 소독기는 기존의 방식보다 빠르고 강력한 소독 효과를 낼 수 있음을 확인하였다.

• 한국식품위생안전성학회지
• /
• 제38권1호
• /
• pp.26-30
• /
• 2023

본 연구에서는 자외선 살균기의 미생물 오염 상태를 분석하고 위생관리 방안을 제시하고자 하였다. 본 실험에 사용된 자외선 살균기는 전라남도 소재 일부 보육시설 98곳의 자외선 살균기를 대상으로 하였다. 일반세균 및 대장균군은 식품공전 미생물 시험법에 따라 실험하였다. 일반 세균은 98개 보육시설 중 67개소(68.4%), 대장균군은 5개 소(5.1%)에서 검출되었다. 식중독세균 실험 결과 Salmonella spp. 등 6종의 식중독세균은 검출되지 않았지만 B. cereus 는 98개 보육시설 중 1개소(2.8%)에서 검출되었다. 자외선 램프 교체 주기에 따른 일반세균 검출율은 3개월 이내가 6개 보육시설 중 3개소(50%), 3개월 이상 6개월 이내가 5개 보육시설 중 3개소(60%), 6개월 이상이 87개 보육시설 중 61개소(70.1%)로 나타났다. 대장균군 검출율은 6개월 이내에는 검출되지 않았으나 6개월 이상이 87개 보육시설 중 5개소(5.7%)로 나타났다. 자외선 살균기의 미생물 오염도는 램프 교체 주기가 길어질수록 미생물 오염도가 높게 나타났다. 또한 자외선 램프 교체 주기가 6개월 이상인 87개 보육시설 중 23개소(26.4%)의 자외선 살균기 반사판에는 물기가 있고 청소상태가 불량한 것으로 나타났다. 이러한 결과를 종합해 볼 때 보육시설에서 사용 중인 자외선 살균기의 위생관리를 위해 주기적인 청소 와 자외선 램프 교체가 필요한 것으로 판단된다. 또한 보육시설 급식담당자들에게 자외선 살균기 청결과 램프 교체에 대한 지속적인 교육이 필요할 것으로 판단되었다.

• 한국버섯학회지
• /
• 제15권4호
• /
• pp.164-167
• /
• 2017

Biological efficiency (BE), the ratio of fresh mushrooms harvested per dry substrate weight, expressed as the percentage of Lentinula edodes, also known as shiitake, was determined using the 'Sanjo 701' strain stored in the Department of Mushroom at the Korea National College of Agriculture and Fisheries. The mycelia were grown in glass columns with varying levels of moisture content and varying mixing periods of 0.5, 1, 2, and 3 hours. The substrate was sterilized using a steam pressure autoclave sterilizer at normal and high pressure to avoid contamination. The results showed that mycelial growth (126 mm/15 days) was optimized at 55% moisture content. The best mycelial growth of 117 mm/15 days was obtained with 2 hours of mixing time. Normal pressure sterilization yielded better results with mycelial growth of 96 mm/15 days at $100^{\circ}C$ compared to 88 mm /15 days with sterilization at $121^{\circ}C$. Mycelial density was higher, i.e. 3(+++), with normal pressure sterilization compared to 2(++) with high pressure sterilization. Furthermore, sawdust mixed with 5% woodchips increased the substrate porosity and yielded higher mycelial growth. Thus, we demonstrated that the optimum harvest or potential increased yield of shiitake can be obtained by modulating moisture content, mixing time, and substrate porosity.

• 한국지역사회생활과학회지
• /
• 제18권2호
• /
• pp.247-263
• /
• 2007

This study was complied to analyze the professional agricultural techniques level and to suggest a desirable direction for the professional education system for women farmer. The research was conducted by using in-field surveys and interviews. Data was gathered by questionnaire from 147 women farmer in five specialized crop regions: strawberry, cucumber, rose, apple, and oyster mushroom. The results obtained are as follows. First, the technique levels in computer usage and electronic commerce, machinery usage, pesticide and fertilizer utilization, facility automation, and eco-agricultural cultivation were low. Second, the demand for professional education, evaluated through technique level by standard management diagnosis, was recognized. Areas of concern included: cucumber (temperature control, carbonic acid gas control, grading, funds management), strawberry (light control, soil temperature control, irrigation watering, shipping), rose (temperature control, light control, funds management, cooperated management), oyster mushroom (growth cabinet sterilizer), and apple (flower bud pinching, defloration, fruit thinning, funds management). Based on the results of this study, the following are suggestions for the planning of a professional education system for women farmer. First, it needs to address formal education in marketing, machinery usage, facilities automation, and techniques in pesticide and fertilizer utilization. Second, it needs to be a multi- level program with appropriate terminology at every level which is suitable to each age and ability of women farmer. Third, it needs a more comprehensive manual developed by need analysis of women farmer and a larger lecturer pool for professional education.

• 한국결정성장학회지
• /
• 제29권6호
• /
• pp.264-269
• /
• 2019

UV LED 적용하여 가정용 소독기를 제조하기 위한 디자인을 연구하였다. UV LED 살균거리 및 시간데이터에 근거하여 가정용 소독기 디자인 개념을 제시하였다. 컴퓨터 보조디자인 소프트웨어, 3D 프린트, 레이저 절달 등 기술을 사용하여 3가지 서로 다른 UV LED 작동방식의 모델을 제작하였다. 이 모델 대해 장단점 분석을 진행하여 최종 디자인 방안을 도출하였다.

• 한국식품영양학회지
• /
• 제4권1호
• /
• pp.81-90
• /
• 1991

This study was conducted a comprehensive survey of 39 elementary schools operating school lunch program in Seoul area. The purpose of this study was to investigate the realities of school lunch program. This method of the research was based on the interview survey with dietitian working at each school with prepared questionnaire. The survey was conducted for 16 days from Dec. 5 to Dec. 20., 1990. The results of this study were as follows ; (1) The average numbers of children supplied with food were 1,244 for each school. It was about 44.3Bb of the students enrolled in the school. The average feeding cost was 738 won per a child for a day. (2) Only one school was operating nutritional education as a regular educational program, and others were operating nutritional education off and on. (3) All nutrient intake except energy were higher than the RDA for school lunch program. (4) The ratio of animal food was 46.2%, and that of vegetable food was 53.8%. (5) The ratio of schools without sterilizer cabinet came to 56.4%, and that of schools without warmer was 97.4%. (6) The facilities for drainage, lighting, ventilation, anti-rat of a cookery were comparatively good.