• Journal of Advanced Marine Engineering and Technology
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• 제8권1호
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• pp.17-36
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• 1984

Since 1973, the competition on the development of fuel saving type internal combustion engines has become severe by the two times oil shock, and new type engines are reported every several months. Whenever these new type engines are developed, new designs are required and they will be offered in the market after performing the endurance test for a long time. But the engine market is faced with a heavy burden of finance, as the developing of a new engine requires tremendous expenses. For this reason, the computer simulation method has been lately developed to cope with it. The computer simulation method can be available to perform the reasonable research works by the theoretical analysis before carrying out practical experiments. With these processes, the developing expenses are cut down and the period of development is curtailed. The object of this study is the development of simulation computer program for the small naturally aspirated four-stroke diesel engine which is intended to product by the original design of our country. The process of simulation is firstly investigated for the ideal engine cycle, and secondly for the real engine cycle. In the ideal engine cycle, each step of the cycle is simulated by the energy balance according to the first law of thermodynamics, and then the engine performance is calculated. In the real cycle imulation program, the injection rate, the preparation rate and the combustion rate of fuel and the heat transfer through the wall of combustion chamber are considered. In this case, the injection rate is supposed as constant through the crank angle interval of injection and the combustion rate is calculated by the Whitehouse-Way equation and the heat transfer is calculated by the Annand's equation. The simulated values are compared with measured values of the YANMAR NS90(C) engine and Mitsubishi 4D30 engine, and the following conclusions are drawn. 1. The heat loss by the exhaust gas is well agree with each other in the lower load, but the measured value is greater than the calculated value in the higher load. The maximum error rate is about 15% in the full load. 2. The calculated quantity of heat transfer to the cooling water is greater than the measured value. The maximum error rate is about 11.8%. 3. The mean effective pressure, the fuel consumption, the power and the torque are well agree with each other. The maximum error is occurred in the fuel consumption, and its error rate is about 7%. From the above remarks, it may be concluded that the prediction of the engine performance is possibly by using the developed program, although the program needs to reform by adding the simulation of intake and exhaust process and assumping more reliable mechanical efficiency, volumetric efficiency, preparation rate and combustion rate.

• Nutrition Research and Practice
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• 제7권1호
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• pp.49-58
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• 2013

The most critical point in the assessment of adherence to dietary guidelines is the development of a practical definition for adherence, such as a dietary pattern score. The purpose of this study was to develop the Korean Diet Score (KDS) based on the Korean Food Balance Wheel and to examine the association of KDS with various lifestyle characteristics and biochemical factors. The dietary data of 5,320 subjects from the 4th Korean National Health and Nutritional Examination Survey were used for the final analysis. The food guide was composed of six food group categories; 'grain dishes', 'fish and meat dishes', 'vegetable dishes', 'fruits', 'milk' and 'oils and sugars'. Based on the recommended serving numbers for each group, the scores measuring adherence to this food guide were calculated from the dietary information from the 24-hour dietary recall questionnaire, and then its correlation with various characteristics was assessed. KDS was significantly associated with several clinical, lifestyle and socioeconomic factors as well as diagnosed disease history. The higher quintile group of KDS showed a significantly lower level in fasting blood glucose, systolic blood pressure, triglycerides, current smoking and drinking as well as higher leisure time activity, house income and education. Furthermore, the KDS quintile group of women was inversely associated with hypertension, osteoporosis and diabetes. A higher KDS quintile was characterized with a higher intake of several critical nutrients, such as Ca, Fe and vitamins as well as a desirable nutrition balance such as the ratio of macronutrients. Our results demonstrate that KDS is a beneficial tool in assessing the adherence to a healthy diet based on the Korean dietary guidelines. We suggest that KDS could be a useful indicator for evaluating the dietary balance of the Korean population.

• 대한환경공학회지
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• 제37권9호
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• pp.511-516
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• 2015

본 연구에서는 수돗물을 끓이는 과정에서의 잔류염소와 소독부산물 제거 특성과 더불어 차를 이용하여 끓였을 때 인체 필수 미네랄 성분의 용출특성에 대해 조사하였다. 현재까지 대부분의 연구가 차를 이용하여 끓였을 때 유해 중금속의 흡착 제거에 초점을 맞추었다면, 본 연구에서는 차를 이용하여 끓였을 때 인체 필수 미네랄 성분의 용출특성에 대해 조사함으로써 보다 건강하고 안전하게 수돗물을 음용하는 방법에 대해 제언하고자 하였다. 조사결과 잔류염소농도 0.7 mg/L 수돗물을 약 20분 가열시 모두 제거되었으며, 소독부산물(THMs, HAAs, CH) 농도는 65%까지 감소하였다. 시판 차 5종(옥수수, 보리, 둥굴레, 현미, 결명자)을 이용하여 끓였을 때 인체 필수 미네랄 6종(칼슘, 칼륨, 나트륨, 마그네슘, 황, 인)의 단위중량당용출량 총합은 결명자차가 최대 9.6 mg/g으로 가장 높았으며, 현미차의 용출량은 1.6 mg/g으로 상대적으로 낮았다. 특히 다른 미네랄에 비해 체내에서 정상혈압유지, 세포물질대사, 효소작용 등 중요역할을 담당하는 칼륨의 용출량이 상대적으로 높은 것으로 조사되었다. 또한 차를 이용하여 수돗물을 끓여 마시는 것만으로도 일부 미네랄성분은 한국인 영양권고 섭취량의 최대 40%까지 섭취 가능한 것으로 조사되었다.

• 한국산업보건학회지
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• 제16권3호
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• pp.233-244
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• 2006

Of many volatile organic detergents for metals, benzine(CAS No. 8030-30-6), of which the toxicity has not yet been proven, has been used as an alternative of the halide compounds in the consideration of toxic effects, global warming and the destruction of ozone layer. In order to evaluate the effects of the benzine on human body by investigating the subchronic inhalation toxicity, to obtain the basic data for establishing the criteria of exposure in working environments and to classify the hazardousness in compliance with the Industrial Safety and Health Act by evaluating the hazardousness, repeated inhalation exposure test was carried with SD rats. The rats were grouped by 10 females and males each. The repetitive inhalation exposures were carried out at 4 levels of concentration of 0 ppm, 60 ppm, 300 ppm, and 1,500 ppm, for 6 hours a day, 5 days a week, for 13 weeks. The results are described hereunder. 1. No death of the animals of the exposed and controlled groups in the test period. Not any specific clinical symptoms, change in feed intake quantity, abnormality in eye test, or change in activity were observed. 2. In the 300 ppm and 1,500 ppm groups, weight reduction in the female groups and weight increase of liver and kidney in the male groups compared with control group were observed with statistical significance(p<0.05). 3. In the blood test, the HCT increased in the male 300 ppm group and the number of hematocyte increased, MCV and MCH decreased in the male 1,500 ppm group. In the female 1,500 ppm group, the HB decreased and the distribution width of the hematocyte particle size increased. In the blood biochemistry test, the TP in the male 1,500 ppm group and the LDH in the female 1,500 ppm group were increased with statistical significance(p<0.05). 4. Under the test conditions of the present study with SD rats, the NOEL was evaluated to be from 60 ppm to 300 ppm for both male and female groups. By extrapolation, the NOEL for human who work 8 hours a day was evaluated to be from 128 ppm to 640 ppm 5. Since the NOEL evaluated in this study do not exceed 60ppm(0.184 mg/L) the test material does not belong to the classification of the hazardous substance "NOEL${\leq}$0.5mg/L/6hr/90day(rat), for continuous inhalation of 6hours a day for 90 days" nor to the basic hazardous chemical substance class 1(0.2 mg/L/6hr/90day(rat) defined by the GHS which is a criteria of classification and identification of chemical compounds. However, considering the boiling point($30-204^{\circ}C$), flashing point($-40^{\circ}C$), vapor pressure(40 mmHg), and the inflammable range(1.0 - 6.0 %), sufficient care should be taken for handling in the safety aspects including fire or explosion.

• 대한한의학회지
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• 제27권3호
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• pp.14-25
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• 2006

Objectives: Samjunghwan has been known to be effective for the treatment of obesity. To show the effectiveness of Samjunghwan in a more scientific way, Samjunghwan extract was prepared and evaluated in high-fat diet rats by measuring the changes of body weight and lipid metabolism as described below. Methods: 245 g of crushed Samjunghwan was extracted with methyl alcohol. The extract was evaporated under reduced pressure to give 21.8 g. For 30 days, the control group rats were given a high fat diet, while the test group rats were given a high fat diet plus Samjunghwan extract. The normal group rats were given a normal diet. 50 mg of Samjunghwan extract per 1 kg of body weight was added to the diet for the test group rats. Results: The control group rats on a high fat diet gained weight by about 27-28% as compared to the normal group, whereas the test group rats on a high fat diet plus Samjunghwan extract lost weight about 6-8% as compared to the control group. A significant increase of liver weight caused by a high fat diet was also inhibited by the same Samjunghwan extract administration. Similar inhibitory effects on the food intake and on the epididymal adipose tissue weight were observed in the high fat diet rats by the administration of Samjunghwan extract. Serum and liver total lipid levels in the control group on a high fat diet increased significantly as compared to the normal group, whereas their serum and liver levels increased less on a high fat diet plus Samjunghwan extract administered test group than the control group. Impressively, serum leptin levels in the test group decreased almost to the level of the normal group, which was well in accordance with the decreased fat contents in the test group rats. Furthermore, the activities of hepatic acetyl-CoA carboxylase and fatty acid synthetase were increased in the control group, while their activities in the test group on a high fat diet plus Samjunghwan extract decreased nearly to the levels of normal group rats on a normal diet. Conclusions: These results showed that the obesity caused by a high fat diet was effectively inhibited the administration of Samjunghwan extract. Our results also showed that the abnormal lipid metabolism caused by a high fat diet was effectively cured by the administration of Samjunghwan extract.

• Toxicological Research
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• 제30권2호
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• pp.91-97
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• 2014

This study aimed to identify changes in the level of neuropeptides among current smokers, former smokers, and individuals who had never smoked, and how smoking habits affect obesity and metabolic syndrome (MetS). Neuropeptide levels, anthropometric parameters, and metabolic syndrome diagnostic indices were determined among male workers; 117 of these had never smoked, whereas 58 and 198 were former and current smokers, respectively. The total sample comprised 373 male workers. The results obtained from anthropometric measurements showed that current smokers attained significantly lower body weight, body mass index, waist circumference, and abdominal fat thickness values than former smokers and those who had never smoked. Current smokers' eating habits proved worse than those of non-smokers and individuals who had never smoked. The level of brain-derived neurotrophic factor (BDNF) in the neuropeptides in the case of former smokers was $23.6{\pm}9.2pg/ml$, higher than that of current smokers ($20.4{\pm}6.1$) and individuals who had never smoked ($22.4{\pm}5.8$) (F = 6.520, p = 0.002). The level of adiponectin among former smokers was somewhat lower than that of current smokers, whereas leptin levels were higher among former smokers than current smokers; these results were not statistically significant. A relationship was found between adiponectin and triglyceride among non-smokers (odds ratio = 0.660, ${\beta}$ value=-0.416, p < 0.01) and smokers (odds ratio = 0.827, ${\beta}$ value=-0.190, p < 0.05). Further, waist circumference among non-smokers (odds ratio = 1.622, ${\beta}$ value=0.483, p < 0.001) and smokers (odds ratio = 1.895, ${\beta}$ value=0.639, p < 0.001) was associated with leptin. It was concluded that cigarette smoking leads to an imbalance of energy expenditure and appetite by changing the concentration of neuropeptides such as adiponectin, BDNF, leptin, and hsCRP, and influences food intake, body weight, the body mass index, blood pressure, and abdominal fat, which are risk factors for MetS and cardiovascular disease.

• Journal of Hospice and Palliative Care
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• 제11권2호
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• pp.99-105
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• 2008

목적: 본 연구에서는 호스피스 병동에 입원한 말기 암 환자들을 대상으로 임상적으로 보다 정확한 잔여 수명을 예측하고자 임종의 시기에 객관적으로 임상적 증상 및 징후들의 변화를 관찰하였다. 방법: 강남성모병원 호스피스센터를 방분한 말기 암 환자를 대상으로 입원 시부터 임종까지 말기에 흔히 나타나는 증상과 신체적 징후의 변화를 관찰하였다. 증상의 정도는 $0{\sim}3$점수화하였으며 신체적 징후는 있다 또는 없다로 구분하였다. 이밖에 활력증후와 통증 정도, 진통제 사용을 관찰하였다. 결과: 호흡곤란, 혼수의 증상은 입원 시와 비교해서 임종 $1{\sim}2$일 전에 악화되었다. 대상자의 활동 수행 능력은 임종 시간이 가까워질수록 점진적으로 감소하였고, 섭취량과 소변 배설량도 줄어들었다. 특히 임종 $1{\sim}2$2일 전부터 현저하게 혈압이 감소하였다. 임종 시점을 기준으로 시기에 따라 증상의 변화가 유의하게 나타난 임상 지표는 활동수행 능력, 수축기 혈압, 구강건조증, 식욕저하, 쇠약감, 변비, 황달, 부종, 욕창, 호흡곤란, 진정, 혼수, 청색증, 호흡이상, 가래 끓는 소리, 눈을 뒤로 젖힘 등이었다. 결론: 말기 암 환자에서 수축기 혈압의 감소, 호흡곤란, 진정, 혼수, 청색증, 호흡이상, 가래 끓는 소리, 눈을 뒤로 젖힘 등의 증상이 나타나면 임종이 임박했음을 예상하여 가족들과 환자가 준비할 수 있도록 해야 하며, 의료진도 임종에 관한 돌봄을 시행하도록 해야 한다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권3호
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• pp.433-442
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• 2013

This study aimed to compare the dynamics of air temperature and velocity under two different ventilation and housing systems during summer and winter in Korea. The $NH_3$ concentration of both housing systems was also investigated in relation to the pig's growth. The ventilation systems used were; negative pressure type for the enclosed pig house (EPH) and natural airflow for the conventional pig house (CPH). Against a highly fluctuating outdoor temperature, the EPH was able to maintain a stable temperature at 24.8 to $29.1^{\circ}C$ during summer and 17.9 to $23.1^{\circ}C$ during winter whilst the CPH had a wider temperature variance during summer at 24.7 to $32.3^{\circ}C$. However, the temperature fluctuation of the CPH during winter was almost the same with that of EPH at 14.5 to $18.2^{\circ}C$. The NH3 levels in the CPH ranged from 9.31 to 16.9 mg/L during summer and 5.1 to 19.7 mg/L during winter whilst that of the EPH pig house was 7.9 to 16.1 mg/L and 3.7 to 9.6 mg/L during summer and winter, respectively. These values were less than the critical ammonia level for pigs with the EPH maintaining a lower level than the CPH in both winter and summer. The air velocity at pig nose level in the EPH during summer was 0.23 m/s, enough to provide comfort because of the unique design of the inlet feature. However, no air movement was observed in almost all the lower portions of the CPH during winter because of the absence of an inlet feature. There was a significant improvement in weight gain and feed intake of pigs reared in the EPH compared to the CPH (p<0.05). These findings proved that despite the difference in the housing systems, a stable indoor temperature was necessary to minimize the impact of an avoidable and highly fluctuating outdoor temperature. The EPH consistently maintained an effective indoor airspeed irrespective of season; however the CPH had defective and stagnant air at pig nose level during winter. Characteristics of airflow direction and pattern were consistent relative to housing system during both summer and winter but not of airspeed. The ideal air velocity measurement favored the EPH and therefore can be appropriate for the Korean environment. Further emphasis on its cost effectiveness will be the subject of future investigations.

• Korean Chemical Engineering Research
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• 제47권3호
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• pp.337-343
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• 2009

선택적 고체순환을 위한 신개념 2탑 유동층 공정에 적용하기 위해 고체분리기와 고체순환시스템을 개발하였다. 고체분리기에 의한 고체분리속도는 고체분사노즐의 유속, 고체층 높이, 고체분사노즐의 직경이 증가함에 따라 증가하였으며 유동화 속도의 영향은 크지 않았다. 본 연구에서 개발한 고체분리기를 이용하여 굵은입자($212{\sim}300{\mu}m$)와 고운입자($63{\sim}106{\mu}m$)의 분리가 가능하였으며 고체분리속도는 66~453 g/min의 범위를 나타내었다. 고체순환시스템의 고체순환속도는 고체분사노즐의 유속, 고체층 높이, 고체유입구멍의 개수가 증가함에 따라 증가하였으며 유동화 속도의 영향은 크지 않았다. 본 연구에서 개발한 고체순환시스템을 이용하여 고운입자의 순환이 가능하였으며 고체순환속도는 65~390 g/min의 범위를 나타내었다. 본 연구에서 개발된 고체분리기와 고체순환시스템을 적용하여 선택적 고체순환이 가능한 2탑 유동층 공정을 구성하였으며 장기연속운전 가능성을 확인하기 위해 약 20시간까지 고체분리-순환 장기연속운전을 실증하였다. 두 유동층의 압력강하 값과 고체분리속도가 안정적으로 유지되어 고체순환이 원활하게 유지되는 것을 확인하였다.

• 대한지역사회영양학회지
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• 제23권4호
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• pp.318-332
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• 2018

본 연구에서는 12주 동안 성인 여성 중 체지방률 40% 이상 또는 BMI 30 이상인 여성을 대상으로 37차시의 비만관리 프로그램일환으로 영양교육과 운동중재를 병행 실시하여 대상자의 식습관 및 운동 습관 조사, 신체성분과 식이섭취와 생화학적 지표에 미치는 효과를 살펴보고자 하였다. 1. 조사대상자의 평균 연령은 44.8세였으며 참여자의 55%가 폐경이었다. 2. 체중조절 관심도 변화에서 체중 조절 방법은 식사조절과 운동이 프로그램 참여 전 34.4%에서 프로그램 후 37.5%로 증가하였다(p<0.01). 3. 신체활동 변화에서 중등도 신체활동을 10분 이상 한날은 프로그램 참여 전 3.20일에서 프로그램 후 4.25일로 증가하고, 스트레칭 등 유연성 운동을 한 날은 프로그램 참여 전 2.60일에서 프로그램 참여 후 3.85일로 유의적으로 증가하였다(p<0.01). 4. 바른 식습관 점수 변화는 프로그램 참여 전 4.15점에서 프로그램 참여 후 7.10점으로 유의적(p<0.001)으로 증가하였다. 5. 에너지 및 다량 영양소 섭취는 프로그램 전후간 차이는 없었으나 식이섬유(p<0.01), 철, 칼륨, 비타민A, 비타민 $B_6$, 나이아신의 섭취는 프로그램 참여 전에 비해 프로그램 참여 후에 유의적으로 증가하였다(p<0.05). 6. 혈압과 혈액 생화학적 특성 지표인 TC, 공복혈당 및 TG는 프로그램 참여 전후 간 유의적인 차이는 없었다. 7. 영양교육과 운동 프로그램 종료 후 체중, 체지방률, 복부둘레 및 내방지방 수치는 유의적으로 감소하였으며, 근육양과 신체발달 점수는 유의적으로 증가하였다(p<0.001). 이상의 결과를 볼 때, 중등도 비만여성에서 12주간 영양교육과 운동 중재 프로그램 실시는 식사의 질을 향상시키고 바림직한 식습관의 변화를 유도하였으며 비만도는 감소하면서 근육양이 증가하여 요요현상이 없이 비만관리 프로그램 교육 내용이 긍정적인 영향을 미쳤으며, 향후 장기적인 비만의 지속관리와 체계적인 연구가 계속되어야 할 것으로 사료된다.