• 상하수도학회지
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• 제27권4호
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• pp.479-487
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• 2013

This study was to investigate characteristics for the pressure wave propagation and the maximum pressure near a rapid closure valve which was installed the end of multi piping network. The multi piping network consists of one inlet and three outlet with straight pipes. The diameter of the pipes including the valve was 100 mm, 80 mm, 80 mm respectively. The valve was rapidly closed with the instantaneous time which was 0.023s in the level for the water hammer. For the simulation, the influence of the pipe thickness and deformation due to pressure-wave-propagation was not considered. CFD was conducted under the following condition : the initial pressure was 1bar in the inlet and the mass flow rate was 7.83 kg/s in the outlet(the velocity in the pipe with 100 mm diameter was 1 m/s). As the valve have conditions that were status with and without fluid flow in the pipe after valve closing, the maximum pressure change and the frequency analysis were examined. As the results, the case that was status with fluid flow appeared the higher maximum pressure than another's, the maximum frequency band was about 10 ~ 11 Hz.

• The Plant Pathology Journal
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• 제18권3호
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• pp.109-114
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• 2002

To evaluate the phylogenetic and taxonomic status of the phytoplasmas associated with water dropwort (Oenanthe javanica DC) disease in Korea and Japan, their 16S rDNA was analyzed. DNAs extracted from water dropworts collected in Korea (Kyongnam province) and Japan (Chiba prefecture) affected by witches' broom and yellows were subjected to PCR using phytoplasma-specific primers, which amplified a 1.4-kbp fragment that included the 16S rDNA. Phytoplasmas were characterized by RFLP analysis using AluI, HaeIII, HhaI, KpnI, MseI, and RsaI restriction enzymes and by sequence analysis of the PCR products. The mater dropwort witches'broom (WDWB) and water dropwort yellows (WDY) 16S rDNA sequences were identical and closely related to onion yellows (OY, 99.9% identity), which belong to the aster yellows (AY) 16S-subgroup. However, the KpnI RFLP analyses clearly distinguished the WDY and WDWB phytoplasmas from the OY phytoplasma. The phylogenetic analysis based on 16S rDNA showed that WDWE and WDY phytoplasmas are members of a relatively homogeneous group that evolved from a common ancestor.

• 한국물환경학회지
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• 제29권1호
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• pp.127-137
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• 2013

Reuse of wastewater will intensify in the coming decades due to water shortage, the change of climatic conditions, the need for industrial and agricultural use and the necessity of improving health and environmental conditions for the growing population. This paper considers (a) the status and trends of wastewater reuse and reclamation in the world, (b) case studies of wastewater reuse projects, (c) analysis of technology level, (d) forecast of global market, and (e) the future views and directions in development of wastewater reuse technologies. Based on the available documented literature, this paper provides a review assessment of the current status of the wastewater treatment processes including potential applications for reuse. Key challenges for both wastewater treatment and reuse are also discussed in the paper and include recommendations, e.g. cost, effluent water quality, energy use and technical solutions, for future developments.

• 한국물환경학회지
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• 제23권4호
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• pp.440-447
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• 2007

This paper is dealing with recent hot issues related with copper toxicity and its criteria, which was caused by a new government policy relocating some industries discharging priority-water quality pollutants from the watershed of Han River to other regions. Author is not interested in arguments between two sides of anti- and pro-policy but would like to go over status of copper pollution and its management and regulatory policy in Korea. From the data of published Research Journals and Reports, it can be concluded that copper is very common metal not only in the effluent from publically owned wastewater treatment plants, but also as a non-point source pollutant in the rainfall runoff. In addition, there have been very few studies personal interests, not by National Fund Basis. In order to enforce a new regulation, national-wide macro and micro-mass balance work of heavy metals should be performed in advance. In particular, background concentration and measurement errors have to be clearly defined before a new standard or criteria is established. The new standard has to be acceptable in terms of the best available technology and cost.

• Asian Pacific Journal of Cancer Prevention
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• 제16권11호
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• pp.4615-4621
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• 2015

Background: The popularity of the water pipe, also referred to as hookah, narghile, shisha or hubble-bubble, has increased tremendously during the past few decades. This study was conducted to determine student water pipe smoking status and perceptions about the effects of water pipe smoking on health in a state university in Ankara. Materials and Methods: This cross-sectional study was conducted between September 2014 and January 2015. The data were collected with a questionnaire and "The Scale of Perception about the Effects of Water Pipe Smoking on Health". The data obtained were evaluated in IBM SPSS (version 20.0) statistical package program in computer. One-way analysis of variance (ANOVA) was used for the analyses by checking homogeneity of variances and Student's t-test. Values of p<0.05 were considered statistically significant. Results: The total mean score obtained by young people who took part in the study was determined as ($\bar{X}=65.20{\pm}1.25$, min=33, max=75). Upon comparison of the total mean scores obtained by young people from the Scale of Perception about the effects of water pipe smoking on health and gender variable, the scores obtained by the females students were higher than those of the male students with a statistically significant difference (t=7.525, p<0.05). A statistically significant difference was observed between the total mean scores obtained by young people with cigarette and water pipe smoking status (for each, t=-3.731, p<0.05; t=-13.987, p<0.05). Conclusions: In conclusion, university students have wrong knowledge on the dangers of water pipe smoking. There was a high prevalence of using water pipes among university students. Gender significantly affected the perceptions about the effect of water pipe smoking on health in our sample.

• 한국물환경학회지
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• 제33권6호
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• pp.680-688
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• 2017

Water quality monitoring for flow rates and BOD/COD/T-N/T-P/SS/TOC concentrations has been conducted in Nakdong river tributaries since 2011. In this study concentrations and loading rates of BOD, T-P, and TOC were analyzed to evaluate water quality monitoring stations using accumulated data at 206 tributary monitoring stations in Nakdong river 2012 ~ 2016. Average concentration ranges for 206 monitoring stations were 0.3 ~ 6.4 mg/L, 0.025 ~ 1.562 mg/L, and 0.6 ~ 10.7 mg/L for BOD, T-P, and TOC, respectively. Additionally, average loading rate ranges were 0.96 ~ 46,040 kg/d, 0.087 ~ 1,834 kg/d, and 1.51 ~ 80,425 kg/d for BOD, T-P, and TOC, respectively. Average concentration for BOD, T-P, and TOC at each monitoring station was evaluated using ambient water quality standards of rivers and water quality regulation level for medium-sized management areas. Average loading rate and specific loading rate (loading rate/drainage basin area) for BOD, T-P, and TOC at each monitoring station was considered to evaluate monitoring stations using suggested classification (BOD, TOC: -1, 1 ~ 10, 10 ~ 100, 100 ~ 1,000, and 1,000 ~ kg/d; T-P: -0.1. 0.1 ~ 1, 1 ~ 10, 10 ~ 100, and 100 ~ kg/d) Using results of this study, various water quality status maps were provided, and three evaluation methods were suggested to determine priority monitoring stations in Nakdong river for rational water quality control and tributaries basin management.

• 한국물환경학회지
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• 제28권4호
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• pp.574-581
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• 2012

It is important to analyze the status of water quality with relation to the stream flow to attain water quality goal more effectively in the unit watersheds for the management of Total Maximum Daily Loads (TMDLs). This study developed a flow duration-water quality distribution graph to figure out water quality appearances on the flow variation and analyzed contributions of water quality observations to the impaired water bodies quantitatively by hydrologic conditions. Factors relating to water quality variation can be analyzed more precisely and assessed on the base of quantified contributions. It is considered that this approach could be utilized to establish a more effective plan for the water quality improvement including the prioritization of pollution reduction options.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.82-91
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• 2008

This paper sought to provide information regarding the water resources in the Philippines, focusing on the issues of water quality, status of water use and water scarcity, and other threats to water availability. Although the country has sufficient amount of water resources, it was found out that water availability is still threatened by some major water resources problems: increasing water demand due to drastic growth in population, water resources pollution, droughts and flooding and weak institutional framework to address these problems. Water quality problems include increasing groundwater and surface water pollution. Moreover, drought and flooding have also increased damages in recent years due to deteriorating watersheds and high economic and population growth. In relation to these, the Government enacted national laws to define and deal with water control and quality management. The objective of this research was to present and evaluate current conditions and issues on Philippine water resources.

• 환경영향평가
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• 제21권3호
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• pp.367-380
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• 2012

There are many long and round shape shores due to terrain characteristics in Daecheong reservoir. Therefore it is indicated different spatial distribution of algae every year since the stream is being regulated by these terrain characteristics and reservoir operation about inflow and outflow discharge. Also oversupply of nutrient salt from tributaries of Daecheong reservoir where pollutants were concentrated generates massive growth of algae and depending on hydrological, reservoir operation condition, those proliferated algae at the stagnant tributaries moves to the mainstream of Daecheong reservoir which could create problems of water quality. In this study, it was analyzed the tendency of algae generation by examining algae occurring status for the last 4 years since 2008, and implemented hydraulic analysis at Daecheong reservoir through numerical tracer simulation by applying 3-dimensional hydrodynamic model, ELCOM. Also it was implemented a quantitative analysis of causal relationship based on the algae generation tendency and hydraulic behavior at Daecheong reservoir. Through numerical tracer simulation in this study, it could be noticed the degree of spread of inflow indicated similar trend to the algae occurring status at Daecheong reservoir and verified the different tendency of algae generation in 2011 unlike previous year caused by the rise of water temperature.

• 한국환경보건학회지
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• 제4권1호
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• pp.41-46
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• 1977

Main objectives of this survey were to find out general sanitary status of water source, draining status and toilet in Shindong Myun, Chungseong Gun. Interviewers of fourteen students visited 1,775 households in this Myun, filled the survey form and checked sanitary conditions of the areas from September 1 to November 30, 1974. Results are summarized as follows: 1. Draining state of pumps is better than that of wells and also the the quality of water sources are better in pumps than in wells. Wells and pumps of 54.1% were constructed more than five years ago. 2. About 66.7% use pump water, 10.5% well water and 8.3% simple piped drinking water system and average water consumption is 22.7l per day per capita. Private water system is 66.0% while public system 27.1%. 3. Water is used for drinking, washing body and cleaning at 53.8% while only for drinking at 7.4%. 4. Nearest pollution sources of drinking water are mainly toilets and stables, and average distances between them are less than ten meters. 5. Toilets of 78.3% are used only by one households and those of 12.9% by two. 6. Toilets of 10.9% are inside main building while those of 85.4% outside main building. 7. Toilet tanks are covered only at 6.3% households while not covered at 95.4%. The contents of tanks are removed about twice a month (40.2%), and 84.1% use them as fertilizer on their own farm and contents of 10.1% are removed by other people. 8. Excreta are utilized on the vegetable farm by 38.2% households, on the vegetable and barley farms by 19.7% and on the paddy fields by 8.2%.