• 한국물환경학회지
• /
• 제25권4호
• /
• pp.560-567
• /
• 2009

Treated or untreated wastewater may be a major source of refractory organic matters (R-OM) in drinking water sources. For this study, spectroscopic characteristics of wastewater OM were investigated using the samples from 20 wastewater treatment plants, which are located at the upstream of the lake Paldang, to suggest a estimate index for R-OM in wastewater. R-OM was quantified by measuring total organic carbon (TOC) concentration of the wastewater samples remaining after 28-day dark incubation. Among the traditional OM indices such as chemical oxygen demand (COD) and initial TOC, CODMn showed the lowest correlation coefficients with R-TOC of the samples. The ratios of carbonaceous biochemical oxygen demand (CBOD) to $COD_{Cr}$ had a better correlation with the percent distribution of R-OM than $BOD/COD_{Cr}$ ratios. terrestrial humic-like fluorescence (THLF) exhibited the highest correlation coefficient with R-TOC among the indices obtained from the synchronous fluorescence spectra of the samples. Milori index, one of the humification indices, showed a good correlation with the percent distribution of wastewater. This study demonstrated that fluorescence properties might be a better indices to estimate the concentrations and the distributions of wastewater OM compared to the specific UV absorbance (SUVA) values. Some useful formulas based on OM spectroscopic characteristics were finally suggested to predict R-OM in wastewater.

• 한국산림과학회지
• /
• 제78권4호
• /
• pp.396-400
• /
• 1989

본(本) 시험(試驗)은 산소지수법(酸素指數法)에 사용(使用)하여 목질판상재료(木質板狀材料)의 상대적(相對的) 연소성(燃燒性)과 그들의 산소지수(酸素指數)를 알아보기 위하여 수행(遂行)되었다. 산소지수(酸素指數)는 일정비율(一定比率) 산소(酸素), 질소(窒素) 혼합기체(混合氣體)의 흐름속에서 재료(材料)가 발염연소(發炎燃燒)를 지속(持續)할 수 있는 최소(最少) 산소농도(酸素濃度)를 말한다. 본(本) 시험(試驗)에서는 산소지수(酸素指數)를 계산(計算)하기 위하여 Dixon과 Massey의 Up and Down법(法)을 사용(使用)하였으며 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 산소지수(酸素指數)는 합판(合板)이 27.9%로 가장 높게 나타났으며, MDF와 파티클보드의 산소지수(酸素指數)는 각각 26.9%와 26.2%이었다. 이것은 합판(合板)이 MDF나 파티클보드에 비해 난연소성(難燃燒性)을 가지고 있는 것을 나타낸다. 2. 산소지수(酸素指數)는 혼합기체유동속도(混合氣體流動速度)에 의하여 영향(影響)을 받지 않았다.

• 대한지역사회영양학회지
• /
• 제10권3호
• /
• pp.253-263
• /
• 2005

This study was conducted to investigate health status of preschool children utilizing anthropometric values and serum biochemical indices. The subjects were 1,159 boys and 1,019 girls in Gumi day-care centers aged 4 to 6 years. The mean height and weight of 4, 5 and 6 year old children were 103.0 cm and 17.1 kg, 107.2 cm and 18.3 kg and 113.4 cm and 20.6 kg, respectively. By the obesity index criteria, $5\%$ of boys and $4\%$ of girls were obese whereas $10\%$ of boys and $9\%$ of girls were underweight. By the Kaup index criteria, $7\%$ of boys and $4\%$ of girls were obese. By the percentage of body fat criteria, $5\%$ of boys and girls were obese. The mean concentrations of serum total cholesterol, triglyceride, HDL-cholesterol, LDL-cholesterol, Atherogenic Index and serum glucose were 154.1-156.5 mg/dL, 80.1-81.9 mg/dL, 46.8-47.4 mg/dL, 90.9-92.8 mg/dL, 2.34-2.39 and 76.4-77.8 mg/dL, respectively. Serum triglyceride level, AI and body fat percentage of obese children were significantly higher than other children and were significantly lower in HDL-cholesterol level (p < 0.05). In addition there were significant correlation between anthropometric values and serum biochemical indices : Kaup index and obesity index were positively correlated to the systolic blood pressure and diastolic blood pressure in boys and girls (p < 0.01) and to the triglyceride concentration in boys (p < 0.05). These results indicate the need of developing and implementation of nutrition education program for preschool children to prevent further development of childhood obesity and to maintain normal serum lipid profiles.

• 한국정밀공학회지
• /
• 제21권6호
• /
• pp.69-76
• /
• 2004

This paper presents a prediction model for the aerosol generation of cutting fluid in turning process. Experimental studies have been carried out in order to identify the characteristics of aerosol generation in non-cutting and cutting cases. The indices of aerosol generation was mass concentration comparable to number generation, which is generally used fur environment criterion. Based on the experimental data, empirical model for predicting aerosol mass concentration of cutting fluid could be obtained by a statistical analysis. This relation shows good agreement with experimental data.

• 한국물환경학회지
• /
• 제22권5호
• /
• pp.784-795
• /
• 2006

The purpose of this study was to assess biological river water quality by using epilithic diatoms at 40 selected sites in Geum, Youngsan, and Seomjin River systems. The sampling and analyses were performed during three seasons including January, April and June in 2005. Various water quality parameters also were analyzed. We attempted to classify the water quality condition by epilithic diatom indices (DAIpo and TDI) with the results of corresponding analyses of various chemical water quality parameters. A five class system was delivered to describe the water quality condition ranged from "very good" to "very poor." We also proposed a way of classifying water quality condition by combining two diatom indices of DAIpo and TDI. Our results showed that biomass of epilithic diatoms varied not only seasonally but spatially; it was not likely that winter diatoms represent average water quality condition, due to high concentration of nutrients. Water quality status assessed by diatom indices was generally worse than that assessed by BOD, indicating that BOD standard likely underestimates the biological condition of the water body. Importantly, nutrient-based diatom index (TDI) generally overestimated organic matter-based index (DAIpo) at most study sites, indicating that diatoms in studied rivers were likely more affected by nutrients than organic matter. Thus, management strategy to improve river water quality in Korea is suggested to emphasize more on the nutrients than organic matters.

• Asian-Australasian Journal of Animal Sciences
• /
• 제15권8호
• /
• pp.1215-1221
• /
• 2002

Normal haematological and biochemical indices along with thyroid hormone status were studied in healthy Kathiawari horses of different age groups (yearling, young stock, adults and old stock) belonging to either sex. Effect of both age and sex was observed on thyroid hormone levels, haematological and biochemical indices. In females, hemoglobin levels was significantly lower in yearlings than adult animals while total leukocyte counts were higher in yearlings than equids of other age groups. Sex had effect only on total erythrocyte counts, mean corpuscular hemoglobin concentration and mean corpuscular hemoglobin in horses of 1-3 years age group (young stock) and on packed cell volume in adult female and male equids. Among biochemical indices, activities of enzymes were observed to be influenced both by age and sex. Creatine kinase, gamma glutamyl transferase, glutamate pyruvate transaminase, glutamic oxaloacetate transaminase and lactate dehydrogenase activities were significantly higher in young and adult equids than animals of other age groups in Kathiawari horses while activity of alkaline phosphatase was significantly higher in yearlings than equids belonging to other age groups in both male and females. However, activity of sorbitol dehydrogenase was unaltered due to both sex and age factor. Albumin, bilirubin direct, bilirubin total, cholesterol, creatinine, protein, triglyceride and uric acid were statistically different in various age and sex groups of horses. Calcium, magnesium and chloride contents were almost same in various age groups of male horses. Significantly higher levels of $T_3$ and $T_4$ were observed in both male and female yearlings as compared to equids of other age groups in both the sexes.

• 한국환경농학회지
• /
• 제33권1호
• /
• pp.44-51
• /
• 2014

하천수질의 공간적 변이 해석에 양분 지표의 활용 가능성을 탐색하기 위해 전남 시 군의 수질 자료(T-N, T-P, BOD, COD)와 양분 지표(화학비료 공급량, 가축분뇨 발생량, 가축분뇨 양분 발생량, 양분수지)의 상관관계를 조사하였다. 수질 T-N은 화학비료 공급량, 가축분뇨 질소 발생량, 양분수지와 모두 정의 상관관계(P<0.05 또는 P<0.01)가 있었고, T-P와 이들 양분 지표와의 상관관계는 95% 수준에서 유의성이 없었지만 가축분뇨 인 발생량(P=0.06)과 양분수지(P=0.09)와는 유의미한 관계가 있었다. 따라서, 전남 지역 하천의 T-N 농도는 농경지 시용 화학비료는 물론 가축분뇨에 의해 영향을 받는 반면 T-P 농도는 화학비료 보다는 부적절한 가축분뇨처리 및 퇴비 과잉 시용에 의해 증가될 수 있음을 의미한다. 가축분뇨와 이를 원료로 제조되는 퇴비는 토양교질 및 금속이온과의 반응성이 낮아 무기태 인에 비해 상대적으로 이동성이 큰 유기태 인을 함유하고 있기 때문에 하천 T-P 농도증가에 기여할 수 있는 것으로 해석되었다. 한편, BOD와 COD는 모두 유기물질 함량이 높은 가축분뇨 발생량과 정의 상관관계(P<0.05 또는 P<0.01)가 있었는데, 이 또한 T-P의 경우와 동일하게 하천 수질에 대한 가축분뇨의 영향을 반영한다. 하지만, 본 연구에서 기상, 지형, 강우유형, 영농활동, 토지이용방식이 상이한 시 군을 대상으로 취득이 용이한 통계자료에 의존하여 양분수지를 분석하여 수질 변동을 해석한 점은 한계로 인정된다. 이와 같은 한계에도 불구하고 본 연구결과는 수질 변동 이해의 측면에서 양분 지표를 이용한 수질의 공간 변이 해석 가능성과 수질 관리의 측면에서 가축분뇨관리(폐수 처리 및 적정 퇴비 시용)의 중요성을 통계적으로 제시한다는 측면에서 의미가 있다.

• Journal of Preventive Medicine and Public Health
• /
• 제33권2호
• /
• pp.193-198
• /
• 2000

일부 농촌지역 주민을 대상으로 혈청 leptin농도와 비만지표의 관련성을 파악하고자 하였다. 역학조사에 참여한 주민 1036명 중 단순무작위표본추출하여 혈청 leptin 농도를 측정한 209명을 연구대상으로 하였다. 체질량지수, 체지방량 등의 비만지수는 신체계측, 생체전기저항분석법으로 측정하였으며 혈청 leptin농도는 면역 방사계수측정 법으로 측정하였다. 혈청 leptin농도는 비만지표인 체질량 지수, 체지방률, 체지방량, 허리둘레, 엉덩이둘레와 유의한 양의 상관관계가 있었다. 혈청 leptin농도는 과체중 또는 비만인에서 저체중 또는 정상인보다 유의하게 더 높았다. 혈청 leptin농도는 남자보다 여자에서 더 높았는데 체질량지수를 보정한 상태에서도 남자보다 여자에서 더 높았다. 혈청 leptin 농도는 남자에서는 허리둘레, 여자에서는 엉덩이둘레와 더 관련이 있어 높은 혈청 leptin농도는 남자에서는 복부형 비만, 여자에서는 둔부형 비만과 관련이 있는 것으로 나타났다. 본 연구에서 혈청 leptin 농도는 비만지표들과 양의 상관관계가 있었고, 정상인보다 비만인, 남자보다 여자에서 더 높았으며, 복부형 비만보다 둔부형 비만과 더 관련이 있었다. 이러한 결과는 비만이 leptin결핍보다는 leptin 저항성과 더 관련이 있다는 가설을 지지하는 것이다.

• 한국대기환경학회지
• /
• 제10권4호
• /
• pp.224-232
• /
• 1994

A new neural network model has been developed to predict short-term air pollution concentration. In addition, a multiple regression model widely used in statistical analysis was tested. These models were applied for prediction of daily maximum ozone concentration in Seoul during the summer season of 1991. The time periods between May and September 1989 and 1990 were utilized to train set of learning patterns in neural network model, and to estimate multiple regression model. To evaluate the results of the different models, several Performance indices were used. The results indicated that the multiple regression model tended to underpredict the daily maximum ozone concentration with small r$^{2}$(0.38). Also, large errors were found in this model; 21.1 ppb for RMSE, 0.324 for NMSE, and -0.164 for MRE. On the other hand, the results obtained from the neural network model were very promising. Thus, we can know that this model has a prominent efficiency in the adaptive control for the non-linear multi- variable systems such as photochemical oxidants. Also, when the recent new information was added in the neural network model, prediction accuracy was increased. From the new model, the values of RMSE, NMSE and r$^{2}$ were 13.2ppb, 0.089, 0.003 and 0.55 respectively.

• 상하수도학회지
• /
• 제34권5호
• /
• pp.311-321
• /
• 2020

In this study, a model to optimize residual chlorine concentrations in a water supply system was developed using a multi-objective genetic algorithm. Moreover, to quantify the effects of optimized residual chlorine concentration management and to consider customer service requirements, this study developed indices to quantify the spatial and temporal distributions of residual chlorine concentration. Based on the results, the most economical operational method to manage booster chlorination was derived, which would supply water that satisfies the service level required by consumers, as well as the cost-effectiveness and operation requirements relevant to the service providers. A simulation model was then created based on an actual water supply system (i.e., the Multi-regional Water Supply W in Korea). Simulated optimizations were successful, evidencing that it is possible to meet the residual chlorine concentration demanded by consumers at a low cost.