• Title/Summary/Keyword: UV sterilization

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Manufacturing and Characteristics of the Electrodeless UV Lamp for Disinfection of the Sewage Effluent (하수 방류수 살균소독을 위한 무전극 UV 램프의 제조 및 특성)

  • Shin, Dong Ho;Lee, Yong Taek
    • Applied Chemistry for Engineering
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    • v.16 no.4
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    • pp.570-575
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    • 2005
  • In this study, we have manufactured electrodeless ultraviolet lamp which has a long life and a high degree of efficiency than the existing electrode UV lamp used in sewage effluent sterilization disinfection. First, we investigated change of UV intensity and temperature of lamp by activation materials. The best results for the dose response experiments were 250 minutes stabilizing to UV intensity of $300{\mu}W/cm^2$ and surface temperature $200{\sim}250^{\circ}C$ in Hg/Ind's weight ratio 95/5. When electrodeless UV lamp emits light for prolonged hours, surface temperature of lamp increases. therefore, temperature change is studied using a duplex lamp for cooling in actual sewerage process. Also, manufactured electrodeless UV lamp showed sterilization efficiency of more than 99.9% as result that experiment manufactured electrodeless UV lamp by E-coli. for sterilization disinfection of sewage effluent.

Experimental Study on the Irradiation and Surface Sterilization Effect of Ultra Violet Ray in Air Conditioning System (공조시스템에서 UV Ray의 조사 및 표면살균성능에 관한 실험적 연구)

  • 홍진관
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.3
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    • pp.250-257
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    • 2004
  • Recently, the use of UVC lamps inside building air-conditioning system has been increasing in both medical and nonmedical buildings for the control of environmental microorganisms. In the present study, irradiance performance test of UVC lamp was carried out and surface sterilization effect of UV ray was investigated by using UV ray irradiation experimental chamber and pilot system. Experimental results show that the effective irradiance of UVC lamp is strongly dependent on air velocity and temperature with exception of relative huminity in air-conditioning system. An individual microbiological kill effectiveness experiment also shows that the fractional kill of two microbiological samples such as E. Coli and Legionella is roughly the same as the estimated fractional kill in the case of chamber test and pilot system test.

Comparison of UV-Irradiation and High Hydrostatic Pressure Sterilization for Storage Stability of Carrot Juice (UV살균과 초고압살균에 의한 당근주스의 저장성 비교)

  • Oh, Nam Seok;Kim, Min Young;Jang, Gwi Young;Baek, So Yune;Joung, Mi Yeun;Kang, Tae Su;Lee, Junsoo;Jeong, Heon Sang
    • The Korean Journal of Food And Nutrition
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    • v.30 no.5
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    • pp.1113-1118
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    • 2017
  • The objective of this study was to investigate the non-thermal sterilization effect of methods such as high hydrostatic pressure (HHP) and UV-irradiation (specifically with regard to the storage stability and shelf-life of carrot juice. The microbial counts of the non-sterilized product increased from 5.51 to 7.34 log CFU/mL up to the fifth day, and then decreased to 5.46 log CFU/mL at six days. UV-irradiation was increased from 2.37 to 4.92 log CFU/mL. HHP was maintained under the 3 log CFU/mL. The pH of UV-irradiation and HHP was maintained withing the range of 6.29~6.30 and 6.20~6.22 during storage. However, the pH arising from non-sterilization decreased from 6.31 to 4.49. The color of non-sterilization changed significantly during storage, but UV-irradiation and HHP were similar during storage. The ${\beta}$-carotene content of non-sterilization was noted to have decreased from 269.45 to $65.19{\mu}g/mL$ during storage. The UV-irradiation and HHP decreased from 263.46 and $268.35{\sim}281.16{\mu}g/mL$ to 243.42 and $244.09{\sim}269.29{\mu}g/mL$, respectively. In conclusion, these findings suggest that HHP can be used for the pasteurization, or sterilization, of carrot juice and the optimal condition is two minutes.

Bactericidal Effect of a 275-nm UV-C LED Sterilizer for Escalator Handrails: Optimization of Optical Structure and Evaluation of Sterilization of Six Bacterial Strains

  • Kim, Jong-Oh;Jeong, Geum-Jae;Son, Eun-Ik;Jo, Du-Min;Kim, Myung-Sub;Chun, Dong-Hae;Kim, Young-Mog;Ryu, Uh-Chan
    • Current Optics and Photonics
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    • v.6 no.2
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    • pp.202-211
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    • 2022
  • In the pasteurization of escalator handrails using ultraviolet (UV) sterilizers, a combination of light distribution and escalator speed has priority over other important factors. Furthermore, since part of the escalator handrail has a curved structure, proper design is needed to improve the sterilization rate on the surfaces touched by users. In this paper, two types of sterilizers satisfying these conditions are manufactured with 275-nm UV-C LEDs, after modeling the three-dimensional (3D) structure of an escalator handrail and simulating optical distributions of UV-C irradiation on the handrail's surface according to light-emitting diode (LED) positions and reflector variations in the sterilizers. Pasteurization experiments with the UV-C LED sterilizers are conducted on six types of gram-positive and gram-negative bacteria, with exposure times of 0.2, 5, and 15 s at an actual installation distance of 20 mm. The sterilization rates for the gram-positive bacteria are 10.63% to 27.94% at 0.2 s, 89.44% to 96.30% at 5 s, and 99.64% to 99.88% at 15 s. Those for the gram-negative bacteria are 57.70% to 77.63% at 0.2 s, 98.90% to 99.49% at 5 s, and 99.88% to 99.99% at 15 s. The power consumption of the UV-C LED sterilizer is about 8 W, which can be supplied by a self-generation module instead of an external power supply.

UV Immune System of Personalized Space (개별공간의 자외선 살균 시스템)

  • Jeong, Ky-Bum;Choi, Sang-Gon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.1
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    • pp.63-70
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    • 2009
  • The air sterilization systems are investigated experimentally in this paper. The goal is to reduce bacteria, mold and viruses in office air by using a UV sterilizer installed inside a partition panel and wall-mounted unit. These systems allow occupants to turn the system on/off and to control the incoming air speed and direction. The partition air sterilization system conditions and sterilizes the air, and then delivers the clean air into the personal task area through the partition panels, which are connected to the pressurized under-floor plenum. Room air exits through the return grills mounted on the ceiling. The wall-mounted air sterilization system sterilizes the air, and then delivers the clean air to the personal task area from the wall. In this study a full-size experimental environment is established to investigate the immunization performance of these air sterilization systems. A typical office space scale is used in this study in order to find an optimal system to achieve a sterilized healthy micro-environment. Multiple system parameters, including volume flow rate and velocity of supplied air, were regulated during the experiments. The more air contact these air sterilization systems had, the better disinfection performance. Over 90% of eradication ratios were obtained by these two air sterilization systems. The results indicate that these systems can efficiently disinfect office air contamination.

Improvement of a UV/Ozone Duplex Sterilizer (UV/Ozone 복합 살균기의 살균력 개선 연구)

  • Jee, Jung-Eun;Yang, Won-Kyun;Park, Eun-Chul;Kim, Kang-Suk;Joo, Jung-Hoon
    • Journal of the Korean institute of surface engineering
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    • v.41 no.2
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    • pp.76-82
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    • 2008
  • We investigated sterilization characteristics of UV lights by counting the number of bacteria units with varying sterilization time and distance from the light source. We focused on an idea that UV light of 184.9 nm could generate ozone and developed a new sterilizer. The UV-ozone duplex system sterilized bacteria faster than UV-only sterilizers. To reduce shadowing effects by target objects, we used UV transparent quartz plate as a support and put a reflecting plate. Distribution of UV irradiation intensity and ozone supply were analyzed by a 3D model and measured by a semiconductor UV sensor. But even with an Al reflector, multi-layered pens could not be treated properly from UV irradiation only. Ozone generating lamp could treat more uniformly multi-layered pens with a stirring fan by supplying ozone to shadowed surfaces.

A study on the design development of a domestic disinfector using UV LED (UV LED를 이용한 가정용 소독기의 디자인 개발에 관한 연구)

  • Zhu, Wang;Sheng, Ying;Kang, Seung-Min;Jee, Moon-Hwan
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.29 no.6
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    • pp.264-269
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    • 2019
  • The design for household sterilizer applying UV LED was studied. Based on UV LED sterilization distance and time data, the concept of home disinfectioner design was presented. Using technologies such as computer aided design software, 3D printing and laser cutting, etc., three different UV LED operating method models were produced. The final design was derived by conducting an analysis of the product's merits and demerits on the three plans from the result of each model.

Study of the Limitation Standards Setting of Sterilization Processing to Vagetable Juice Contain Barley Sprout (보리새싹 함유 녹즙의 살균공정 한계기준 설정에 관한 연구)

  • Bang, In-Hee;Joung, Mi-Yeun;Kwon, Sang-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.367-373
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    • 2016
  • This study was performed to set a limitation rule to the UV sterilization process for green vegetable juice containing barley sprouts. The main constituents of the green vegetable juice, viz. barley sprouts, organic Angelica keiskei, carrots, organic dandelion, kale, wild parsley, Angelica keiskei and cabbage, were provided by the CSJ company located in Jincheon, Chungbuk, from December 1st, 2015 to March 1st, 2016. Our manufacturing process followed the general manufacturing process of a general green vegetable juice manufacturer. Table 1 shows the mixing ratio for the green vegetable juice. This green vegetable juice includes 18% vegetable sprouts, 3% barley sprouts, 18% angelica utilis makino, 1% orange concentrate, 4% apple concentrate, 6% fructooligosaccharide, 10% vegetable fermentation juice, 0.4% lemon concentrate and 39.6% purified water. We conducted UV sterilization at levels 10, 8 and 5 with powers of 230W, 320W and 320W, respectively. The UV sterilization was conducted twice at 25Hz and then once at 40Hz. In the bacterial tests after sterilization, the number of bacteria in the dandelions decreased from $2.56{\times}10^8CFU/mL$ to $5.96{\times}10^3CFU/mL$. In addition, no food poisoning or coliform bacteria were detected. Thus, this study provides the information required for setting a limitation rule using bacteria tests in the UV sterilization process for green vegetable juice.

Changes in Quality of UV Sterilized Takju during Storage by Honeycomb Type-UV Sterilizer (허니컴방식 UV 살균기를 이용한 살균 탁주의 저장 중 품질변화)

  • Lee, Jang-Woon;Jung, Jin-Joo;Choi, Eun-Ju;Kang, Sung-Tae
    • Korean Journal of Food Science and Technology
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    • v.41 no.6
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    • pp.652-656
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    • 2009
  • A cylindrical ultraviolet (UV) sterilization system was developed for decreasing microorganisms in takju. The takju was passed through 110 strips of honeycomb-type teflon tubing with 9 UV lamps (1,395 W) set between the teflon tubes. Thus, during passage, the takju was effectively exposed to the UV rays without loss. In terms of the overall quality aspects of the takju, the optimum sterilization condition was set for 4 min at 2 L/min. A 2-3 log cycle decrease in viable cell numbers of total bacteria and fungi was observed at this operating condition. Quality changes in the UV-sterilized takju were examined via UV irradiation of samples followed by storage at 30oC for 8 days. To evaluate the quality changes, pH, amino nitrogen content, acidity, reducing sugar content, and viable cell numbers of total bacteria and fungi were measured. Increases in pH, acidity, and amino nitrogen content were observed in both the takju control and UV sterilized takju with increasing storage time. However, reducing sugar content was decreased in both samples. The L, a, and b values of the control takju and UV sterilized takju showed similar trends over the storage period. Viable cell numbers of fungi did not change in the control or UV sterilized takju during storage, showing approximately $10^8\;CFU/mL$ and $10^4-10^5\;CFU/mL$, respectively. In addition, viable cell numbers of total bacteria remained lower in the UV sterilized takju over 4 days compared to the non-sterilized takju.

A Study of Sterilization Effect of Long-wavelength UVA-LED Irradiation on Bacteria Causing Eye Diseases (장파장의 자외선 LED 광원을 이용한 안질환 세균의 살균효과)

  • Lee, Cheol-Woo;Jeong, Kyeong-In;Hwang, Kwang-Ha;Lee, Seok-Ju;Yoo, Geun-Chang
    • Journal of Korean Ophthalmic Optics Society
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    • v.17 no.1
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    • pp.99-105
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    • 2012
  • Purpose: The purpose of this study is to demonstrate inactivation effect of UVA-LED ultraviolet radiation upon Pseudomonas aeruginosa and Staphylococcus aureus which are the major bacteria causing eye diseases. Methods: The small sterilization device was made using UVA-LED of 400 nm. After Pseudomonas aeruginosa was diluted to $10^{-7}$ and Staphylococcus aureus to $10^{-5}$ and diluted solutions were put onto each liquid medium. They were irradiated by 400 nm of UVA for different amount of time; 15 min, 30 min, 60 min, 120 min, 240 min, 360 min and 480 min each. Results: The data from sterilization test was solved to regression line equation and the target log inactivation was obtained. The 3 log inactivation UV irradiation value of Pseudomonas aeruginosa was 54,847 UV dose ($mJ/cm^2$) and irradiation time was 135.42 min while the 3 log inactivation of Staphylococcus aureus was 39,066 UV dose ($mJ/cm^2$) and irradiation time was 98.72 min. Conclusions: The inactivation effect of sterilization method using 400 nm of UVA-LED upon Pseudomonas aeruginosa and Staphylococcus aureus has been verified and it is considered as a useful method in inactivating the contact lenses.