• 한국토양비료학회지
• /
• 제44권1호
• /
• pp.48-52
• /
• 2011

The effect of soil water content on the transformation potential of N compounds derived from hydrolysis of urea applied in a reclaimed tidal soils which was saline-sodic was observed to evaluate nitrification rates of urea. Soil samples were collected from Moonpo series at the newly reclaimed area in Saemanguem. For the transformation potential of N compounds from urea (46% N), newly reclaimed tidal soils (RS) were amended with urea at the rates of 0, 10, and 20 kg $10a^{-1}$. With leachate obtained from the incubated RS in a leaching tube at $25^{\circ}C$, urea hydrolysis and nitrification were measured for a total of 30days. The cumulative amounts of $NO_3{^-}$-N in each of the four soils treated with urea was linear with time of incubation. Results showed that increase in pH occurred with increasing application rate of urea and volumetric water content due to hydrolysis of urea. The total N in the RS was decreased with incubation time, indicating that rates of urea hydrolysis was influenced by soil moisture conditions. Also, the cumulative amount of nitrate in RS gradually increased with increase in time of incubation.

• 식품보건융합연구
• /
• 제7권6호
• /
• pp.17-24
• /
• 2021

This study investigates the exercise-physiological changes in stages through the movement of the automatic stepper and to analyze the usefulness of the automatic stepper. For 18 male university students, out of 10 levels, 5 level and 10 level of automatic stepper exercise were performed. At each 10, 20, 30 minutes during exercise, 5 and 10 minutes after exercise stop the subjects were examined to analyze the changes in energy consumption after minutes, respiratory exchange rate, heart rate, oxygen consumption per body weight, METs, cumulative energy consumption, and lactic acid to verify the usefulness of the automatic stepper. The mean and standard deviation were calculated using the SPSS, and one-way ANOVA with repeated measure was performed to verify the difference in the mean between time periods. The LSD method was used for the post-hoc test, and the significance level was set to α = .05. There were no significant changes in both 5 and 10 level, but the cumulative energy consumption over time increased significantly. In addition, as a low-intensity exercise intensity is shown, a low increase in lactic acid indicated a safe exercise level. In future studies, in-depth studies of various variables through regular exercise programs are needed for those who need safe exercise.

• 대한생식의학회:학술대회논문집
• /
• 대한생식의학회 2007년도 제53차 추계학술대회 초록집
• /
• pp.97-97
• /
• 2007

• 설비공학논문집
• /
• 제16권12호
• /
• pp.1227-1233
• /
• 2004

Air handling unit (AHU)'s air filter pressure difference is important for energy consumption and indoor air quality. Both energy Performance data and air filter differential pressure of AHU in real office buildings were monitored and analyzed to investigate quantitatively energy impact as dust buildup level on air filter grows. We also modeled and simulated CAV system using HVACSIM＋ program to examine the energy effect of dust buildup on filters. Through analysis of time series pressure drop data, the filter pressure difference rate has been increased due to cumulative supply air flow rate increase. As filter pressure drop increased to 1 inch water column, it is found that the supply air flow rate was decreased by 10%, the chilled water flow rate was increased by 5.9% and the pump energy consumption was increased to 5.9%.

• 대한예방의학회:학술대회논문집
• /
• 대한예방의학회 1994년도 교수 연수회(환경)
• /
• pp.651-657
• /
• 1994

To assess quantitatively the association between benzene exposure and leukemia, we examined the mortality rate of a cohort with occupational exposure to benzene. Cumulative exposure for each cohort member was estimated from historical air-sampling data and, when no sampling data existed, from interpolation on the basis of existing data. The overall standardized mortality ratio (a measure of relative risk multiplied by 100) for leukemia was 337 (95 percent confidence interval, 154 to 641), and that for multiple myeloma was 409 (95 percent confidence interval, 110 to 1047). With stratification according to levels of cumulative exposure, the standardized mortality ratios for leukemia increased from 109 to 322, 1186, and 6637 with increases in cumulative benzene exposure from less than 40 parts per million-years (ppm-years), to 40 to 199, 200 to 399, and 400 or more. respectively. A cumulative benzene exposure of 400 ppm years is equivalent to a mean annual exposure of 10 ppm over a 40-year working lifetime; 10 ppm is the currently enforceable standard in the United States for occupational exposure to benzene. To examine the shape of the exposure-response relation, we performed a conditional logistic-regression analysis, in which 10 controls were matched to each cohort member with leukemia. From this model, it can be calculated that protection from benzene induced leukemia would increase exponentially with any reduction in the permissible exposure limit.

• 농업과학연구
• /
• 제46권4호
• /
• pp.907-914
• /
• 2019

Ammonia (NH₃) that reacts with nitric or sulfuric acid in the air is the major culprit contributing to the formation of fine particulate matter (PM_2.5). NH₃ volatilization mainly originates from nitrogen fertilizer and livestock manure applied to arable soil. Cation exchange capacity (CEC) of peat moss (PM) and zeolite (ZL) is high enough to adsorb ammonium (NH₄⁺) in soil. Therefore, they might inhibit volatilization of NH₃. The objective of this study was to compare the effect of PM and ZL on NH₃ volatilization from upland soil. For this, a laboratory experiment was carried out, and NH₃ volatilization from the soil was monitored for 12 days. PM and ZL were added at the rate of 0, 1, 2, and 4% (wt wt^-1) with 354 N g m^-2 of urea. Cumulative NH₃-N volatilization decreased with increasing addition rate of both materials. Mean value of cumulative NH₃-N volatilization across application rate with PM was lower than that with ZL. CEC increased with increasing addition rate of both materials. While the soil pH increased with ZL, it decreased with PM. Increase in CEC resulted in NH₄⁺ adsorption on the negative charge of the external surface of both materials. In addition, decrease in soil pH hinders the conversion of NH₄⁺ to NH₃. Based on the above results, the addition of PM or ZL could be an optimum management to reduce NH₃ volatilization from the soil. However, PM was more effective in decreasing NH₃ volatilization than ZL due to the combined effect of CEC and pH.

• 대한간호학회지
• /
• 제4권1호
• /
• pp.121-134
• /
• 1974

This study is an attempt to evaluate the use of an oral contraceptive by: 1. Deforming the acceptance rate of the oral contraceptive according to socio-demographic characteristics 5. Estimating the duration of the use of the contraceptive f. Discovering reasons why the contraceptive was discontinued 4. Computing the cumulative continuation and discontinuation rate according to socio-demographic characteristics, history of pregnancies, and attitude of husband at the time of selection of the contraceptive. One hundred sixty-eight women of child bearing age (14-49 years), residing in Yonhee Dong, Seoul, Korea and registered as oral contraceptive accepters at Yonsei Community Health Center, were interviewed during a three week period in 1973. The questionnaire was designed to determine the socio-demographic characteristics of the oral contraceptive accepters, the current status of their family planning practice, medical reactions if any, discontinuation practice, and the duration of the use of the contraceptive. The major findings of the study were as follows; 1. The acceptance rate was highest for women between 30 and 34 years of age, the mean age being 34.4 years. 2. Fifty six point five percent of all respondents said that thirty years of age was the ideal age to stop having children. 3. The average number of living children was 3.5 and fifty four point eight percent of respondents felt 2 boys and I girl was the ideal number of children. 4. The average number of pregnancies was 5.2 and the average number of induced abortion was I. 4. 5. Fifty eight point eight percent of the respondents had experience in the use of contraceptive methods in the past. 6. Forty one point seven percent of the respondents replied that they chose the oral contraceptive because, "it was not complicated to use." 7. Sixty four point eight percent of the women said their husband approved of their taking the pill. 8. The cumulative discontinuation rate was sixty point five percent of the total respondents for one year in first segment. 9. Sixty six point nine percent of the respondents had experienced side-effect while using the pill. The side effects for 68.9 percent of these women were castro-intestinal upsets. Twenty point eight percent of the women who had side effects consulted with medical personnel about them. Women who had more education had more side effects. 10. Seventy three point two percent of the women who discontinued the pill did so because of medical reasons. Women who were younger discontinued the pill for personal reasons more-often than older women. Among personal reasons listed for discontinuing the pill was the attitude of the husband. 11. The average duration of continuance of the contraceptive was 5.3 cycles under 29 years of age; 7.4 cycles between 30 and 34 years of age; and 8.4 cycles over 40 years of age. 12. The discontinuation rate was seem to increase sharply in the early cycle and increase more slowly in later cycle. Conclusions and suggestions: Since the attitude of the husband was shown to be important, the current family planning program should be expended to include approach to husband. For women who must use the oral contraceptive, education and support must be enhanced so that the discontinuation rate due to side effects will be decreased.

• 수도
• /
• 제24권5호통권86호
• /
• pp.29-44
• /
• 1997

Sewage sludge produced in Korea was 1,275,800 tons (dewatered sludge cake) per year in 1996, which is 3,495 tons per day, 0.303% of 11,526,100 tons per day of sewage treated in 79 sewage treatment plants. Sludge production has been and will be increasing in accordance with construction of new facilities for sewage treatment. Most of the sludge is currently disposed by landfill and ocean dumping, but it is becoming difficult to find suitable sites for landfill, particularly in big cities such as Seoul. In addition, rapid increase of landfill cost is anticipated in a near future. Current trend for sludge disposal in advanced countries is land application. Over the past 10 to 20 years in the United States, sludge management practices have changed significantly, moving from disposal to beneficial use. They use biosolid for utilization instead of sludge for disposal. Under the Clean Water Act of 1972, amended in 1987 by Congress, the U.S. EPA was required to develop regulations for the use and disposal of sewage sludge. The EPA assessed the potential for pollutants in sewage sludge to affect public health and the environment through a number of different routes of exposure. The Agency also assessed the potential risk to human health through contamination of drinking water sources or surface water when sludge is disposed on land. The Final Rules were signed by the EPA Administrator and were published (Federal Register, 1993). These rules state that sewage sludge shall not be applied to land if the concentration of any pollutant in the sludge exceeds the ceiling concentration. In addition, the cumulative loading rate for each pollutant shall not exceed the cumulative pollutant loading rate nor should the concentration of each pollutant in the sludge exceed the monthly average concentration for the pollutant. The annual pollutant loading rate generally applies to applications of sewage sludge on agricultural lands. The most popular beneficial use of sewage sludge is land application. The sludge has to be stabilized for appling to land. One of the stabilization process for sewage sludge is lime stabilization process. The stabilization process is consisted of the stabilizing process and the drying process. Stabilization reactor can be a drum type reactor in which a crossed mixer is equipped. The additive agents are a very reactive mixture of calcium oxide and others. The stabilized sludge is dried in sun drier or rotary kiln.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
• /
• pp.535-538
• /
• 2006

The coastline of the Choa Phraya Rivermouth in the Upper Gulf of Thailand has been changed drastically. The western side especially at Ban Laem Sing was eroded for 400 meter in 26 years or with the rate of 15 meter per year on the average. The Metropolitan Electricity Authority has granted five years research project to us to study the efficiency of the electric pole fence as a mean to reduce the wave force and increase sedimentation rate inside for mangrove replantation. If the method works efficiently, it will be used to reclaim the coastal land loss in other areas in Thailand. The project was done since 2005 after the fence was constructed completely in October 2005. The oceanographic surveys were conducted before and after the construction in northeast monsoon season to study the impact of physical oceanographic forces on the coastline change. The sedimentation rates were measured each month. It is rather low about 2 cm/month. The subsiding rate from the load of deltaic sediment and groundwater withdraw using boring data is about 30 mm/year. The cumulative sinking rate is 55.8 cm from 1978 to 1995. We have tried to design the method of mangrove plantation in this area. The remote sensing data such as LANDSAT and aerial photos from 1987 to 2002 for 15 years were used to compute the rate of coastline change at each 50 m section along the western side of the rivermouth.

• Clinical and Experimental Reproductive Medicine
• /
• 제7권1_2호
• /
• pp.35-38
• /
• 1980

Korean family planning program has been adopted as a part of the Economic Development Plan with strong national government backup. After initiation of family planning program, the increase rate of total population declined from 2.6 percent during 1955-1960, to 2.1 percent in 1960-1975, and 1.6 percent in 1979. Of course, we do not ascribe this population increase rate decline to the national family planning program alone. Other contributing factors have been changes such as growing numbers of induced absortions, a rising marriage age and economic development. Currently, 2,600 family planning workers are assigned in all myun of the country. 21 percent of the works are registered nurse, 9 percent are midwife and aid nurses occupy 70 percent (Table 1). Authorized clinics are 2,329 which composed 1,765 IUD clinics, 1,070 vasectomy clinics and 1,150 Fimale sterilization clinics (Table 2). Cumulative contraceptive services provided by government program, 1962-1974 is illustrated in Table 3. After government program in family planning has been initiated (1962-1978), estimated number of births averted by each methods was measured (Table 4). From 1962 to 1978, tendency of contraceptive acceptors is illustrated in Table 5 showed that IUD, oral pill and condom program is decreasing and in other hand, sterilization program is increasing very much. Attitude change toward family size (1965-1978), contraceptive practice and son preference are showed in Table 7, 8, respectively. Auther concluded that future program in family planning should target to the point, that smaller family size norm for maternal health should be emphasized rather than smaller size family for national development.