• Membrane and Water Treatment
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• 제10권5호
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• pp.339-352
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• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• Tribology and Lubricants
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• 제39권4호
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• pp.139-147
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• 2023

Cavitation phenomena observed during the operation of a submerged plain journal bearing (PJB) can affect bearing performance parameters such as dynamic coefficients, whirl frequency ratio, and critical mass. This study presents numerical solutions of the Reynolds equation for steadily and dynamically loaded submerged PJBs with half-Sommerfeld (HS), Reynolds, and Jakobsson-Floberg-Olsson (JFO) cavitation models when the supply pressure is larger or equal to the cavitation pressure. The loads at various eccentricity ratios are identical; however, the attitude angle is approximately 6% smaller when the eccentricity ratio is between 0.2 and 0.7 and the JFO model is used, compared to that when the Reynolds model is used. Dynamic coefficients obtained with the HS and Reynolds model show good agreement with each other, except for k_xz, which is sensitive to changes in the force normal to the rotor weight, and is attributed to the difference in the attitude angle obtained with each cavitation model. Stiffness coefficients are determined using the pressure distribution in the film, and therefore, when the JFO model is used, the direct stiffness coefficients are affected and show opposite signs for most eccentricity ratios. The mass-conservative JFO model can predict at least a 30% smaller critical mass compared to that using the HS and Reynolds models. Thus, the instability analysis results can change based on the cavitation model used in a submerged PJB. The results of this research indicate that the JFO model should be used when designing a rotor system supported by submerged PJBs.

• 한방안이비인후피부과학회지
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• 제25권1호
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• pp.84-103
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• 2012

Objectives : The middle school students'life style were studied with focus on Body Mass Index(BMI). Information was collected during 1st June 2009 to 10th July from 397 students(both male and female) by the subjective survey centered on personal characteristic, understanding about health in general, everyday activities, eating habits, preference in food, understanding about diet and obesity, and thoughts about fitness and diet. Methods : Students were selected from six classes by convenience sampling, then the final analysis was performed on 397 self-administered questionnaires, excepting 5 questionnaires, which have insincere answers. The data collection was carried out by SPSS(V.14.0 English Version), and the data was verified by $x^2$-test, ANOVA, multiple regression analysis. Results and Conclusion : The survey subjects were in the following distribution of body weights - underweight: 63.6%, normal weight: 29.5% and 6.9% were overweight. There was significantly different between BMI and mothers' occupation and satisfaction with school life(p<0.05). As for the analysis(multiple regression analysis) on understanding about health, the factors that affect BMI are self recognition of figure and efforts to reduce weight. In terms of efforts for one's own health, 78.2% of under weight and 82.3% of normal weight were taking active initiatives. But 85.2% of the overweight students were not giving any efforts. As for the free time activities, more than half answered, 'playing with computers'(48.4 - 66.7%, 1.57 hours on average). As for TV, on average, 2.03 hours were spent in overall. And it turned out that the overweight students spent more time watching TV by 46.49 minutes(0.77 hours) on average(p<0.05). 7.4 hours was the average sleeping time. As for the eating habit,'quantity of meal, snack, meal between meals, fat reduction, and supplementary food'were shown to be related to the BMI(p<0.05). The instant food, meat and sweet food were shown to be also related to the BMI. In terms of knowledge about overweight and diet, only 8 students(2% of the total) answered all 10 questions correct. On average, 7-8 questions were correctly answered(53.9 %). When the scores were analyzed against the BMI by classifying the scores to high, middle and low categories, it showed a relationship by different weight group(p<0.02), and the overweight students had higher score by 0.82 compared to the underweight students. When thoughts and attitude on fitness and diet were analyzed in relationship to the BMI, the result was only - "I try to eat fruits more often"(fruits)(p<0.00).

• Toxicological Research
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• 제4권1호
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• pp.1-12
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• 1988

In order to evaluate the effect of cigarette smoking on the pharmacokinetics of theophylline in Koreans, doses of 4.5 to 5.0 mg/kg of theophylline, as injectable aminophylline, were administered to 12 normal young volunteers (male, 22 to 35 yrs;mean, 26 yrs) through intravenous infusion over 30 minutes, and pharmacokinetics of theophylline were tested. Among subjects, six were nonsmokers and the other were smokers (range 1 to 2 packs/day). Also the correlations between plasma and saliva theophylline concentrations were investigated by determining the concentrations of theophylline in saliva simultaneously at each plasma sampling time. The total body clearances of theophylline in smokers (Mean${\pm}$SD, 0.0578${\pm}$0.0092 L/hr/kg)were appreciably higher than thoxe of nonsmokers (Mean${\pm}$SD, 0.0359${\pm}$0.0063 L/hr/kg), and the half-lives of theophylline in smokers averaged 5.36${\pm}$1.22hr, and significantly shorter than those of nonsmokers which averaged 9.14${\pm}$1.73hrs(p<0.005). But the apparent volumes of distribution of theophylline did not show any significant difference between smokers (Mean${\pm}$SD,0.44 ${\pm}$0.05L/kg) and nonsmokers (Mean${\pm}$SD, 0.46${\pm}$0.05L/kg). The average concentration ratios in saliva and plasma were 0.61 in smokers and 0.56 in nonsmokers after 2 hrs following drug administrations, and the smoker group had a slightly higher value of ratio(S/P) than the nonsmoker group (p<0.05). The correlations between saliva and plasma theophylline concentration in smokers were r=0.852(p<0.0005) within 2 hr and r=0.985(p<0.0005) after 2 hrs and also those of nonsmokers were r=0.729(p<0.0005) within 2 hrs and r=0.957(p<0.0005) after 2 hrs starting the infusion. From the results, it was found that smoking cigarettes had significantly increased the clearance of theophylline and that the relationships between saliva and plasma theophylline concentrations in all subjects were better after 2 hrs than within 2 hrs starting the infusion of aminophlline.

• 대한치과보철학회지
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• 제32권4호
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• pp.484-514
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• 1994

Cantilever bridge is widely used by mny clinicians, but its worst mechanical character, so called Class I lever system, makes dentists hesitate to restore the missing tooth with it. Therefore it is important to study stress of the cantilever bridge. In this study, two models of cantilever bridges that restores the missing mandibular second molar with two abutment teeth were constructed. One model was a type of cantilever bridge supported by a normal alveolar bone, the other one was supported by an alveolar bone resorbed to its 1/3 of root length. Maximum bite force(550N) and funtional maximum bite force(300N) were vertically applied to the distal end of the pontic, distal 1/3, and distal half of the pontic. And each force was also applied to centric occlusal contacts as a distributed force. Total 16 loading cases were compared and analyzed with 3-dimensional finite element method. The results were as follows: 1. The stress was concentrated on the joint of the pontic and the retainer, grooves, and distal cervical margin of the posterior retainer. 2. In case of maximum bite force(550N) at the end of the pontic, the risk of fracture at the joint of the pontic and the retainer was high. 3. In case of distributed force in centric occlusion and functional maximum bite force(300N), the stresses were less than the yield strength of the type VI gold for any loading cases. 4. In case of alveolar bone resorption, the occlusal force to the cantilever pontic caused more stress on the root apex and less stress on the alveolar crest region of the distal surface of the posterior abutment. 5. In case of alveolar bone resorption, the displacement was larger than that of normal alveolar bone in all loading cases.

• Journal of Preventive Medicine and Public Health
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• 제10권1호
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• pp.34-43
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• 1977

This study attempts to examine the performances of Myun Health Workers-the frontline workers in the Korean rural health care delivery system. The time-activity approach was mainly utilized as a measuring tool. This study was undertaken in September 1976 with 35 Myun Health Workers at the Kang Wha County. The pretested time-activity approach sheets were filled out daily for one month by those Myun Health Workers themselves. Statistical means and variances of analysis were utilized for statistical method in comparing some activities and functions converged into time distribution Findings: 1. The workers's average working hours derived in this study is 8 hours and 48 minutes per day, which takes half an hour longer than normal schedule. 2. They spend 56% working hour for direct services, in other words, the main function, 22% for supportive function, and 22% for other activities, the unrelated health services. 3. Considering the total working hours of main function, out-center activity is far more than in-center services with the ratio of 70% to 30% respectively, which proves, therefore, that the main activity of the workers is home visiting. 4. It takes 20 minutes purely for home visiting and takes 14 minutes for transportation. 5. This research also indicates that such factors as characteristics of the health workers and myun influence in shaping the structures of the worker's function and activity: a. The workers whose working site is located in myun office spend 15% among total working hours in carring out official myun activities, which is incidentally unrelated to health services, while the health subcenter have no rooms for administrative jobs for myun office. b. The workers whose office is in health subcenter contribute much time in doing main function and those working in special project distribute more time in performing supportive function. c. The types of workers are another dominant factor to influence the components of worker's functions and activities. MCH workers and MPW I spend much time for manipulating main function. d. MPW II, whose function is reorganized by special project in 2 myuns shows different pattern of time distribution compared to the TB worker orFP worker in the ordinary area. MPW II distributes their time evenly in performing MCH program, T.B. Program, F.P. program and education activity, while the unipurpose workers engage in carring out only their dominant role. e. Another variables which involve the variation of the worker's activity can be illustrated with the variables like target population, size of myun and convenience for transportation, among which the latter two are remarkable factors in determining the time for out-center service.

• 대한간호학회지
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• 제7권2호
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• pp.43-59
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• 1977

The Community Health Service considers the family as a service unit and places the emphasis of its service on the health problems and the nursing needs of the family rather than the individual. From the conceptual point of view that tile community health service is both health maintenance and health promotion of the family, the community health nurse should have a knowledge of the growth and development of the family and be responsible for the comprehensive support of normal family development. The community health nurse often is in a position to make a real contribution to normal family development. In order to investigate the relationship between the areas of nursing need and family development, the following objectives were established 1. To discover the general characteristics of the study population by the stage of family development. 2. To discover specific nursing needs in relation to the family developmental stage, and to determine the intensity of the nursing needs and the ability of the family to cope with these needs. 3. To discover overall family health nursing problems in relation to the family developmental stage and determine the intensity of the nursing need and the problem solving ability of family. Definitions : The family developmental stages as classified by Dually were used stage 1. Married couples(without children) stage 2. Childbearing Families (oldest child birth to 30 months of age) stage 3. Families with preschool children (oldest child 2½-to 6 years) stage 4. Families with schoolchildren (oldest child 6 to 13 years). stage 5. Families with teenagers (oldest child 13 to 20 years) stage 6. Families as launching centers (first child gone to last child′s leaving home). stage 7. Middle- aged parents (empty nest to retirement) stage 8. Aging family member (retirement to death of both spouses) The areas of nursing need were defined as those used in the study, "A Comprehensive Study about Health and Nursing Need and a Social Diagram of the Community", by tile Nursing research Institute and Center for population. and Family Planning, July 1974. The study population defiled and selected were 260 nuclear families ill two myron of Kang Hwa Island. Percent, mean value and F- test were utilized in tile statistical analysis of the study result. Findings : 1. General characteristics of the study population by tile family developmental stage ; 1)The study population was distributed by the family developmental stage as follows : stage 1 : 3 families stage 2 : 13 families stage 3 : 24 families stage 4 : 41 families stage 5 : 50 families stage 6 : 106 families stage 7 : 13 families stage 8 : 10 families 2) Most families had 4 or 5 members except for those in stage, 1, 7, and 8. 3) The parents′ present age was older in the higher developmental stage and their age at marriage was also younger in the higher developmental stages. 4) The educational level of parents was primarily less than elementary school irrespective of the developmental stage. 5) More than half of parents′ occupations were listed as laborers irrespective of the developmental stage, 6) More than half of the parents were atheists irrespective of the developmental stage. 7) The higher the developmental stage(from stage 2 to stage 6 ), the wider the distribution of children′s ages. 8) More than half of the families were of middle or lower socio-economic level. 2. Problems in specific areas of nursing need by family developmental stage, the intensity of nursing need and the problem solving ability of the family : 1) As a whole, many problems, irrespective of the developmental stage, occurred in tile areas of Housing and Sanitation, Eating Patterns, Housekeeping, Preventive Measures and Dental care. Problems occurring ill particular stages included the following ; stage 1 : Prevention of Accident stage 2 : Preventive Vaccination, Family Planning. stage 3 : Preventive Vaccination, Maternal Health, Family Planning, Health of Infant and Preschooler. stage 4, 5 : Preventive Vaccination, Family Planning, Health of School Children. stage 6 : Preventive Vaccination, Health of School Children. 2) The intensity of the nursing need in the area of Acute and Chronic Diseases was generally of moderate degree or above irrespective of the developmental stages except for stage 1. Other areas of need listed as moderate or above were found in the following stages: stage 1 : Maternal Health stage 3 . Horsing and Sanitation, Prevention of Accident. stage 4 . Housing and Sanitation. stage 5 : Housing and Sanitation, Diagnostic and Medical Care. stage 6 : Diagnostic and Medical care stage 7 : Diagnostic and Medical Care, Housekeeping. stage 8 : Housing and Sanitation, Prevention of Accident, Diagnostic and Medical Care, Dental Care, Eating Patterns, Housekeeping. 3) Areas of need with moderate problem solving ability or less were as follows : stage 1 : Diagnostic and Medical Care, Maternal Health. stage 2 : Prevention of Accident, Acute and Chronic Disease, Dental Care. stage 3 : Housing and Sanitation, Acute and Chronic Disease, Diagnostic and Medical Care, Preventive Measure, Dental Care, Maternal Health, Health of Infant and preschooler, Eating Patterns. stage 4 : Housing and Sanitation, Prevention of Accident, Diagnostic and Medical Care, Preventive Measure, Dental Care, Maternal Health, Health of New Born, Health of Infant and Preschooler, Health of school Children, Eating Patterns, Housekeeping. stage 5 . Housing and Sanitation, Prevention of Accident, Acute and Chronic Disease, Diagnostic and Medical Care, Preventive Measure, Dental Care, Preventive Vaccination, Maternal Health, Eating Patterns. stage 7, 8 : Housing and Sanitation, Prevention of Accident, Acute and Chronic Disease, Diagnostic and Medical Care, Preventive Measures, Dental Care, Preventive Vaccination, Eating Patterns , Housekeeping. Problem occurrence, the degree of nursing need and the degree of problem solving ability 1 nursing need areas for the family as a whole were as follows : 1) The higher the stages(except stage 1 ), the lower the rate of problem occurrence. 2) The higher the stage becomes, the lower the intensity of the nursing need becomes. 3) The higher the stages (except stages 7 and 8), the higher. the problem solving ability. Conclusions ; 1) When the nursing care plan for the family is drawn up, depending upon the stage of family development, higher priority should be give to nursing need areas ① at which problems were shown to occur ② where the nursing need is shown to be above moderate degree and ③ where the problem solving ability was shown to be of moderate degree. 2) The priority of the nursing service should be Placed ① not on those families in the high developmental stage but on those families in the low developmental stage ② and on those areas of need shown in stages 7 and 8 where the degree nursing need was high and the ability to cope low.

• 대한토목학회논문집
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• 제4권1호
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• pp.1-10
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• 1984

본(本)논문(論文)은 재료(材料)의 성질(性質)이 직교(直交)하는 방향(方向)으로 상이(相異)한 이방성(異方性) 구조체(構造體)에 부분등분포(部分等分布) 전단하중(剪斷荷重)이 경계(境界)에 작용(作用)할 경우의 수직응력(垂直應力)과 전단응력(剪斷應力)을 나태내는 엄밀해법(解法)을 제시(提示)하였다. 이 해법(解法)은 평형조건(平衡條件)과 적합조건(適合條件)을 동시에 만족하는 탄성론적(彈性論的)인 엄밀 해법(解法)이다. 따라서 이러한 문제(問題)를 해석(解析)하기 위하여 Airy 응력함수(應力凾數)를 이용(利用)하였다. 본해법(本解法)의 타당성(妥當性)을 증명(證明)하기 위하여 이방성(異方性)인 경우의 방정식(方程式)들의 이방성상수(異方性常數)들을 등방성(等方性)인 경우의 상수(常數)들로 대치(代置)할 경우에 등방성(等方性)인 경우의 방정식(方程式)들로 변환(變換)되지 않으면 안된다. 이를 검토(檢討)하기 위하여 L'hospital의 법칙(法則)을 이용하였다. 그 결과(結果) 이방성(異方性)인 경우의 모든 방정식(方程式)들은 등방성(等方性)인 경우의 방정식(方程式)들로 정확히 변환(變換)되었고 이 식들은 이미 연구된 자료(資料)의 값들과 비교(比較)된 결과(結果) 정확히 일치(一致)되었다. 또한 집중하중(集中荷重)의 경우와의 관계(關係)에서는 부분등분포하중(部分等分布荷重)의 특별(特別)한 경우가 집중하중(集中荷重)임을 고려하고 L'hospital의 법칙(法則)을 이용(利用)하면 부분등분포하중(部分等分布荷重)의 경우의 방정식(方程式)들은 바로 집중하중(集中荷重)의 경우의 방정식(方程式)들로 변환(變換)됨을 알 수 있다. 본 결과(結果)로 미루어 보아 해법(解法)의 타당성(妥當性)이 입증(立證)되었다고 할 수 있다. 본해법(本解法)의 방정식(方程式)들은 간단(簡單)한 형태(形態)로 구성(構成)되어 있어 수치결과(數値結果)를 정확히 누구나 얻을 수 있는 장점이 있다. 응력(應力)의 값을 나타내는 수치결과(數値結果)를 이방성재료(異方性材料)인 3단합판(合板)과 중첩합판을 예로 들어 나무결을 2가지 방향(方向)으로 강축(强軸)을 바꾸어 각각의 수직(垂直) 및 전단응력(剪斷應力)을 구(求)하여 도표(圖表)로 표시(表示)하였으며, 그 결과 응력(應力)의 분포(分布)는 재료(材料)의 성질과 강축(强軸)의 방향(方向)에 따라 현저하게 달라지는 현상을 볼 수 있다.

• 대한토목학회논문집
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• 제5권3호
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• pp.95-105
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• 1985

본(本) 논문(論文)은 재료(材料)의 성질(性質)이 직교(直交)하는 방향(方向)으로 상이(相異)한 이방성(異方性) 구조체(構造體)에 모멘트 하중(荷重)이 경계(境界)에 작용(作用)할 경우의 수직(垂直) 및 전단응력(剪斷應力)을 나타내는 엄밀 해석(解析)을 제시(提示)하였다. 모멘트하중(荷重)은 물론 탄성하중(彈性荷重)은 물론 탄소성하중(彈塑性荷重)과 극한하중(極限荷重)에 이르기까지의 하중(荷重)의 변화(變化)에 따른 구조체(構造體) 내부(內部)의 응력(應力)들을 해석적(解析的)인 방법(方法)으로 해석(解析)하였다. 이 해법(解法)은 평형조건(平衡條件)과 적합조건(適合條件)을 동시에 만족하는 탄성론적(彈性論的)인 엄밀해법(解法)이다. 따라서 이러한 문제(問題)를 해석(解析)하기 위하여 Airy 응력함수(應力凾數)를 이용(利用)하였다. 본(本) 해법(解法)의 타당성(妥當性)을 증명(證明)하기 위하여 이방성(異方性)인 경우의 방정식(方程式)들의 이방성(異方性) 상수(常數)들을 등방성(等方性)인 경우 상수(常數)들로 대치(代置)할 경우에 등방성(等方性)인 경우의 방정식(方程式)들로 변환(變換)되지 않으면 안된다. 이를 검토하기 위하여 L'hospital 외 법칙(法則)을 이용(利用)하였다. 그 결과(結果) 이방성(異方性)인 경우의 모든 방정식(方程式)들은 등방성(等方性)인 경우 방정식(方程式)들로 정확히 변환(變換)되었고 이 식(式)들은 이미 연구된 자료들의 값들과 비교(比較)된 결과(結果) 동일한 값을 얻었다. 본(本) 해법(解法)의 방정식(方程式)들은 간단(簡單)한 형태(形態)로 구성(構成)되어있어 수치결과(數値結果)를 누구나 정확히 얻을 수 있는 장점이 있다. 응력(應力)의 값을 얻기 위한 재료(材料)의 성질(性質)이나 구조적(構造的) 성질(性質)에 따라 결정되는 이방성상수(異方性常數)를 3 단합판중첩합판과 강보강판(鋼補鋼板), 철근콘크리트판(板)을 예(例)를 들어 표(表)로 표시(表示)하였고 수치결과(數値結果)는 3 단합판(段合板)을 예(例)를 들어 나무결을 두가지 방향(方向)으로 강축(强軸)을 바꾸어 각각의 수직(垂直) 및 전단응력(剪斷應力)을 구(求)하여 도표(圖表)로 표시(表示)하였으며 그 결과 응력(應力)의 분포(分布)는 재료(材料)의 성질(性質)과 보강부재(補强部材)의 배치 내용에 따라 달라지는 강축(强軸)의 방향(方向)에 따라 현저하게 달라지는 현상을 볼 수 있다.

• Nuclear Engineering and Technology
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• 제20권2호
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• pp.88-104
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• 1988

이차원의 유한요소법을 이용하여 axisymmetric R-$\theta$system으로 나누어서 정상과 부하추종 운전시에 핵연료 페렛트와 피복관의 열역학적 거동을 분석하기 위해서 FURA전산코드를 개발하였다. 온도분포와 내부압력을 정확히 계산하기 위해서 페렛트와 피복관의 변형과 핵분열의 기체방출을 전체 핵연료봉 길이로 고려하였다. 열역학적 평 형방정식을 얻기 위해서 Galerkin's Technique과 가상일의 원리를 사용하였고 역학적 해석을 위해서 탄성-소성, 크리프뿐만아니라 스엘링, 재배열, 고밀화 현상등을 고려하였다. 기하학적 모델에서는 4-결점 요소라 페레트 길이의 1/2만을 택하였다. 비선형식을 안정하게 해석하기 위해서 음해법을 도입하여 뉴튼-랩손 반복법을 적용하였다 이 코드의 검증은 해석해와 실험데이타로 비교하였다. 핵연료봉의 일반적인 거동은 axisymmetry system으로 계산하였고 균열된 페레트에 접촉하는 피복관의 거동은 R-$\theta$system을 사용하였다. 부하추종에 의한 피복관의 변형시효의 민감도는 출력율, 진동수, 진폭등으로 비교하였다.