• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.89-96
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• 2008

The objective of this study is to establish the algorithm for contamination criterion map based on the recent weather condition. Present criterion was established by the study on the countermeasure of salt contamination for electrical equipment. It did not represent recent weather condition. Therefore it is necessary to develop a contamination criterion map for assessment of contamination in design areas in Korea. To develop contamination criterion map of seashore areas, we used relational numerical formula based on past measurement data with the amount of rainfall, geomorphic variables(elevation slope, land use). These results are expected to be used as a reference material for design distribution facilities in seashore areas.

• The Journal of Korean Society for School & Community Health Education
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• v.8 no.2
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• pp.79-95
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• 2007

A study was conducted in order to develope HACCP model in school lunch in Korea. Results: 1. Of 22 menus 4(18%) were non heating processes (#1), 2(9%) were food handling by using hands (#2), and 16(73%) were heating processes (#3). Of 279 menus 36(12.9%) belong to process #1, 8(2.9%) to process #2, and 235(84%) to process #3. 2. The critical control points for process #1 were contamination by hands of food handlers, and unsanitary food preparation habits of food handlers. Those for process #2 were improper heating temperature, contaminations by food handlers' hands, and unsanitary food handling habits, and cross contamination by unclean utensils and equipment. 3. Management criteria for the CCPs were conditions of food storage, refrigeration, freezing, food cooking temperature, personal hygiene, washing and sanitization of utensils and equipment. 4. Monitoring criteria for CCPs were observation, temperature checking, inspection of utensils and equipment, and practice of good personal hygiene. 5. Corrective actions were refusal of unsafe products, correction of improper temperature, proper cleaning and sanitization, and proper reheating time and temperature.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.409-415
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• 2008

Recently, Indoor air quality (IAQ) is one of the most important problem in our daily life of modern societies. Mechanical ventilation system is being recommended as an effective method to improve IAQ in apartment houses. And then, in Korea, building industry should install ventilation system in apartment house by the building construction code. In this study, to improve IAQ caused by microbial and chemical contaminant such as bacteria and TVOC, three types of mechanical ventilation system of apartment house including HRV were simulated by multizone modeling. Simulation results suggest an appropriate and economical renovation method of apartment house ventilation system for reducing indoor air contamination.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1150-1158
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• 2009

Since equipment currently being used in the department of radiological technology comes into contact with patients carrying diseases, there inevitably will be the existence of pathogenic bacteria. Therefore, in order to increase the importance of using disinfectant in hospital infection precaution and the recognition of hospital infection management, comparisons were made by measuring the bacterial contamination levels in radiology room within the department of radiological technology and comparing the measurements with post disinfection levels. Disinfecting the rooms from detected bacteria was conducted with water, tissue cleaner, or 70% alcohol. When measuring bacterial contamination levels in radiology rooms, a variety of bacteria was detected. When disinfecting the interior of radiology rooms the effectiveness of destroying bacteria and preventing hospital infection was greatest when using 70% alcohol compared to water, tissue cleaner and ventilation. Therefore, there needs to be a development of a better antiseptic for destroying bacteria because there is a possibility for hospital medical equipment to be constantly contaminated. Efforts need to be made to prevent hospital infections and patient secondary infection by disinfecting and sterilizing equipment.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.359-367
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• 2005

This study was carried out to understand the contamination patterns of Listeria in pork processing plants. A total of 402 samples were collected from carcass, pork during processing, surfaces of equipment and environment, and 238 isolates of Listeria species were identified. L. innocua was found in 64.7% of the isolates, L. monocytogenes in 33.2%, and L. welshimeri in 2.1%. Random amplified polymorphic DNA (RAPD) analysis performed to investigate the origin and routes of Listeria contamination, showed 21 composite types of L. monocytogenes and 26 composite types of L. innocua. It was confirmed that Listeria contamination begins with contaminated incoming carcass and ever-present contaminants in the processing environments. The persistence and dissemination of the same strain of L. monocytogenes and L. innocua throughout the processing line revealed that the sanitation standard operating procedure should be implemented to minimize the risk of colonization in the workplace. Molecular subtyping of L. innocua allowed us to tracing the possibility of cross-contamination during processing.

• Progress in Superconductivity and Cryogenics
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• v.25 no.1
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• pp.6-10
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• 2023

2 K superfluid helium cryogenic system is the crucial component of many large accelerators. When the cryogenic system is operating at 2K@3129Pa, many room-temperature parts are connected to superfluid helium via tubes. Air Leakage in these connections may lead to air contamination of the cryogenic system. Air contamination may cause equipment failure in cryogenic systems and, in extreme cases, render the entire accelerator system inoperable. Helium guard is a technique that guards against air contamination of these sub-atmospheric pressure connections in 2 K superfluid helium cryogenic system. This paper introduces a typical 2 K cryogenic distribution design for large accelerators, and make risk analysis of air contamination. Finally, the analysis of specific leakage points and detailed engineering design are presented, which may be used as a reference when designing of a 2 K superfluid helium cryogenic distribution system.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.167-172
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• 2007

This study was conducted to determine the effect of hygienic processing (HP) on the reduction of microorganisms during manufacturing of saengshik with two vegetables (carrots and cabbage) and two grains (barely and glutinous rice) compared to general processing (GP). For GP, distilled water was used for washing raw materials and equipment. For HP, aqueous ozone (3 ppm) in combination with 1% citric acid and 70% alcohol were used for washing raw materials and the equipment, respectively. In carrots, after cutting, total aerobic bacteria (TAB), yeast and mold (YM) and coliforms were significantly increased to 5.19, 8.04 and 2.08 ($log_{10}$ CFU/g), respectively (p<0.05). Washing effectively reduced the increased microorganisms from cross contamination during cutting, but cross contamination increased with subsequent GP drying and milling procedures to 8.56, 8.27 and 3.71 ($log_{10}$ CFU/g) for TAB, YM and coliforms, respectively (p<0.05). On the other hand, HP washing of carrots with 3 ppm ozone in combination with 1% citric acid showed higher antimicrobial effect than GP washing, significantly decreasing the number of microorganisms (p<0.05). Further cross contamination did not occur through drying and milling due to cleaning the equipments with 70% alcohol prior to processing. After milling, the number of TAB, YM and coliforms were significantly decreased to 3.89, 4.47 and not detectable level ($log_{10}$ CFU/g), respectively (p<0.05). Similar results were observed in cabbage and grains. During storage for two months at different temperatures (22 or $4^{\circ}C$), there were no changes in numbers of spoilage microorganisms in the packaged saengsik after either processing. This suggests the importance of HP for the reduction of microorganisms during saengsik production, and demonstrates the effectiveness of disinfection at each processing stage in minimizing contamination levels to enhance microbial safety of saengshik products.

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.124-124
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• 2007

• Journal of the Semiconductor & Display Technology
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• v.15 no.2
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• pp.70-73
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• 2016

Previously proposed contamination detecting sensor was revisited for the investigation of the liquid tendency. Experiments revealed different output voltages for several kinds of liquid input, but showed same values for various flow rates of each liquid. The transmittance of the liquid was measured, and it is well correlated with the voltages. Linearity in values and the compensation of the sensor to sensor deviation were tried to obtain. And, long term test was performed as attached at the manufacturing equipment in the field.

• Agribusiness and Information Management
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• v.9 no.1
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• pp.18-22
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• 2017

It takes lots of time and labor if a worker have to measure the water quality at a certain but designated time every day in an un-automated aqua farm. In addition, if the equipment is soaked in the sea water consistently, it will be contaminated by diverse floating matters and barnacles, and it often becomes mal-functional within 2~3 months. Therefore, we need to develop a system with which the sensed data could be checked in real time and operated automatically, while preventing the contamination of the sensor, a crucial component for water quality measuring equipment, as much as possible, and increasing the replacement cycle. We have developed a non-cleaning water quality measuring equipment and its software which are used in the fishery household of offshore aqua farms. By providing the workers with a mobile application which has a function of monitoring the water quality in real time, they can check the situation directly without going to the fishery household.