• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.192-198
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• 2005

Recently, Automobile manufacturers regarding stability, economic environmental-friendly problems by the development of automobile. This reason is increasingly strict environmental regulations to lower fuel consumption and reduce emission. Designing more efficient and low emission control exhaust system results in more efficient Performance, reduced back Pressure and higher convert efficiency. Also to reduce the noise and the vibration of the automobile. According to develop variable type muffler, dual muffler and active intelligence exhaust system unit. Improvement in engine performance and fuel consumption rate, higher conversion efficiency demand information of pressure fraction and heat characteristics. To be able to determine these factor fur we experiment on each case of exhaust system unit. In this study, how back pressure is distributed in flow-through in exhaust system and how to design exhaust system flexibleness, efficiency, lower back pressure and optimal performance. This study furnish basic data for engineers, technicians.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.6
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• pp.586-599
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• 2014

During the last two decades, indoor air quality and volatile organic compounds (VOCs) have been of concern in Korean society due to their nature of potential health impacts. In order to investigate the pollution levels of VOCss in indoor environments, establishment of a solid test method for monitoring the airborne VOCss is essential. In Korea, a method based on adsorbent sampling and GC analysis coupled with thermal desorption was proclaimed as the Korea Standard Method for Indoor Air Quality Test. This study was carried out to examine some inherent problems of the VOCs measurement method. The VOCs method does not describe in detail preparing the standard samples. The standard samples may be prepared by impregnation of either liquid standard solutions or a mixture of standard gases. In this study, we investigated the optimal temperature condition for transferring the liquid standards onto a standard adsorbent tube. As a result, keeping the impregnation temperature at $250^{\circ}C$ will be recommended in regard of the boiling points of multiple target analytes and the thermal stability of the adsorbent. We also demonstrated some problems associated with handling of a syringe used for transferring the standard solutions onto the adsorbent tubes, and a best way to get rid of the syringe problems was suggested. Finally, a number of field works were conducted to evaluate the performance of adsorbent sampling methods. Comparison of different adsorbent tubes, i.e. tube packed with single sorbent (Tenax) and double sorbents (Tenax with Carbotrap), revealed that 30 to 40% differences between the two groups, implying that sampling efficiency is depending on the volatility and the strength of adsorbents. However, duplicate precisions for VOCs sampling with a same type of adsorbent and at same flow rates appeared to be satisfactory to be all within 20%, which is a quality control guideline. Distributed volume precisions were also found to be within a guideline value, 25%, although the precision was in general inferior to the duplicate precision. The Korea indoor VOCs test method should be more refined and improved in many aspects, particularly procedure and instrumentation for preparing the standard samples and specification of quality control assessment.

• Korean Journal of Community Nutrition
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• v.8 no.5
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• pp.781-793
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• 2003

This study was performed to investigate the stress level and health-related behaviors of nurses and to provide basic information for developing educational programs in the health care field. The subjects of this study were 197 nurses and 94 nursing assistants working at hospitals in the Kyung-nam area. A survey was conducted using a self-administered questionnaire in November, 2002. The results were as follows : The average age and work experience of the subjects were 26.9 and 5.6 years, respectively. The number of respondents in the shift and non-shift operations was equally distributed. The mean height and weight were 161.2 cm and 52.7 kg, respectively. Even though the average body mass index (BMI) and obesity index were normal in the subjects, 9.2% of the subjects were overweight/obese, while 28.9% of the subjects were under weight, according to the obesity index. The mean score of stress was 27.5 \pm$\pm$ 4.6 out of 50 points. Most of the subjects were highly stressed about the amount of their work, problems regarding their future, and relationships with their superiors. With regard to changes in food intake due to stress, 44.1% showed an increased intake, while 32.3% showed a reduced intake. The degree of health consciousness of the married nurses, those over 36 years of age, and those with over 10 years of nursing experience was significantly higher than that of the unmarried nurses, those under 35 years of age, and those with under 10 years of nursing experience (p<0.01). Fifty-one point three percent of the subjects thought their health status was unhealthy. Fifty-seven percent of the subjects had tried weight control. Their main reason for trying weight control was to have a slender figure (62.3%), and their methods of weight control were moderation in intake(45.6%), exercise and dieting (36.9%). TV/radio (49.5%) and newspaper/magazines (47.1%) were the primary sources of nutritional and health information for the subjects, and professional (25.1%) and the internet (13.4%) were ranked relatively highly. The food components of most concern to the subjects during meal time were (in order of importance) fats (51.9%), calories (40.2%) and salt (35.1%). The subjects considered 'taking a rest' (73.5%) as the most important factor in maintaining an optimal health status, followed by self-relaxation (56.4%), moderation in diet (39.5), bathing or using a sauna (25.7%) and exercising (22.7%).