• Environmental Engineering Research
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• v.22 no.3
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• pp.329-338
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• 2017

Nanofiltration (NF) technology is a membrane-based separation process, which has been pervasively used as the high-effective technology for drinking water treatment. In this study, a kind of composite polyamide NF thin film is selected to investigate the removal efficiencies and mechanisms of 14 trace drugs, which are commonly and frequently detected in the drinking water. The results show that the removal efficiencies of most drugs are quite high, indicating the NF is an effective technology to improve the quality of drinking water. The removal efficiencies of carbamazepine, acetaminophen, estradiol, antipyrine and isopropyl-antipyrine in ultrapure water are $78.8{\pm}0.8%$, $16.4{\pm}0.5%$, $65.4{\pm}1.8%$, $71.1{\pm}1.5%$ and $89.8{\pm}0.38%$, respectively. Their rejection rates increase with the increasing of their three-dimensional sizes, which indicates that the steric exclusion plays a significant role in removal of these five drugs. The adsorption of estradiol with the strongest hydrophobicity has been studied, which indicates that adsorption is not negligible in terms of removing this kind of hydrophobic neutral drugs by NF technology. The removal efficiencies of indomethacin, diclofenac, naproxen, ketoprofen, ibuprofen, clofibric acid, sulfamethoxazole, amoxicillin and bezafibrate in ultrapure water are $81{\pm}0.3%$, $86.3{\pm}0.5%$, $85.7{\pm}0.4%$, $93.3{\pm}0.3%$, $86.6{\pm}2.5%$, $90.6{\pm}0.4%$, $59.7{\pm}1.7%$, $80.3{\pm}1.4%$ and $80{\pm}0.5%$, respectively. For these nine drugs, their rejection rates are better than the above five drugs because they are negatively charged in ultrapure water. Meanwhile, the membrane surface presents the negative charge. Therefore, both electrostatic repulsion and steric exclusion are indispensable in removing these negatively charged drugs. This study provides helpful and scientific support of a highly effective water treatment method for removing drugs pollutants from drinking water.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.5
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• pp.323-334
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• 2020

Adsorption by granule activated carbon(GAC) is recognized as an efficient method for the removal of perfluorinated compounds(PFCs) in water, while the poor regeneration and exchange cycles of granule active carbon make it difficult to sustain adsorption capacity for PFCs. In this study, the behavior of PFCs in the effluent of wastewater treatment plant (S), the raw water and the effluents of drinking water treatment plants (M1 and M2) located in Nakdong river waegwan watershed was monitored. Optimal regeneration and exchange cycles was also investigated in drinking water treatment plants and lab-scale adsorption tower for stable PFCs removal. The mean effluent concentration of PFCs was 0.044 0.04 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.037 0.011 PFOA g/L, for S wastewater treatment plant, 0.023 0.073 PFHxS g/L, 0.000 0.00 PFOS g/L, 0.013 0.008 PFOA g/L for M1 drinking water treatment plant and 0.023 0.073 PFHxS g/L, 0.000 0.01 PFOS g/L, 0.011 0.009 PFOA g/L for M2 drinking water treatment plant. The adsorption breakthrough behaviors of PFCs in GAC of drinking water treatment plant and lab-scale adsorption tower indicated that reactivating carbon 3 times per year suggested to achieve and maintain good removal of PFASs. Considering the results of mass balance, the adsorption amount of PFCs was improved by using GAC with high-specific surface area (2,500㎡/g), so that the regeneration cycle might be increased from 4 months to 10 months even if powdered activated carbon(PAC) could be alternatives. This study provides useful insights into the removal of PFCs in drinking water treatment plant.

• Korean Journal of Health Education and Promotion
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• v.22 no.4
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• pp.17-40
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• 2005

Objective: The purpose of the this study was to test the effect of the alcohol preventive educational program for elementary school students through developing the web-based learning instruments. It will prevent the serious alcohol problem for adolescents and be the opening-learning according to learner's needs beyond the traditional classroom learning which has limitation of space and time. Method: This research designed based on web-based instructional system design by In-sung Jong(1997). This study was performed on the elementary school students who are the six grade in M city. The number of experimental group was 72 and control group's number was 72, totaled 144. Data were collected from September, 30th, 2004 to November, 5th, 2004, totaled 37days. The pretest and the posttest for web-based alcohol preventive education program were tested about knowledge and attitudes toward drinking. After the performance, the posttest was also tested the effect of this program under items by the interest of web-based learning, satisfaction, adequateness of material and so on. The data analysis was done using SPSS/Win 11.0 program. Result: The results of this study are as follows: 1) Compared with control group, experimental group which was educated the web-based alcohol preventive educational program for elementary school students was improved the knowledge on drinking, thin there was no significant difference. However, it showed significant difference between two groups after education. It was, therefore, partially supported. 2) Compared with control group, the experimental group which was educated the web-based alcohol preventive educational program for elementary school students showed significant difference in attitudes toward drinking. After education, it showed no significant difference attitudes. toward drinking between experimental group and control group. It was, therefore, partially supported. 3) The degree of learning motivation was an average.595 of 1 after learning applied to by the web-based alcohol preventive educational program for elementary school students. Then, it is relatively more higher than the result of existing studies. So, it showed that the motivation was done well. 4) Correlation among study variables It showed that there was the significantly positive correlation between knowledge and attitudes toward drinking of pretest experimental group. Also, there was the significantly positive correlation between attitudes toward drinking and learning motivation of pretest and posttest experimental group. Conclusion: I found that the web-based educational program helps the elarning process for the health education in the school field which the instructional materials lack. As a result, the web-based education motivates the learner's pleasure and promotes the learners interest. Also, it is possible for students to learn according to their own learning pace, repeated learning and active learning participation in the necessary parts. Therefore, I think the web-based educational program is worth as a intervention to get positive influence for the health education.

• 한국노년학
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• v.39 no.4
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• pp.763-780
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• 2019

The purpose of this study is to examine whether middle-aged people's anxiety about economic well-being in old age affects problem drinking and to verify whether there is relationship between anxiety about economic well-being in old age and to examine the problem drinking could be mitigated by social supports. We used the 2015 Korean Adults' Psycho-Social Anxiety Survey data. To detect the moderating effect of social supports, we employed a method of hierarchical multiple regression analysis. The result of the study showed that the higher the anxiety about economic well-being in old age among middle-aged adults, the higher was the likelihood of problem drinking. Moreover, the relationship between anxiety about economic well-being in old age and problem drinking could be moderated by social supports. Based on the empirical findings, this study suggests that education to deal with middle-aged people's anxiety about economic well-being in old age should be developed and recommends that counseling and community programs for social supports to be implemented as a preventive approach.

• Membrane Journal
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• v.17 no.2
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• pp.99-111
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• 2007

It is impossible to remove toxic organic substances that are recognized as a cancer caused suspicious element in drinking water using the conventional water purification method. This study introduces groundwater into a reaction chamber as an effective amount of water to process this water using a mixed method of AOP oxidation and M/F membrane and purifies it as a desirable level by artificially mixing such toxic substances in order to effectively process the water. Based on this fact, this study configures an optimal operation condition. The VOCs existed in toxic substances was investigated as a term of phenol and toluene, and agricultural chemicals were also investigated as a term of parathion, diazinon and carbaryl. The experiment applied in this study was performed using a single and composite soolution. In the operation condition applied to fully dissolve and remove such substances, the amount of $H_2O_2$ injected in the process was 150 mL of a fixed quantity, the value of pH was configured as $5.5{\sim}6.0$, the temperature was controlled as a range of $12{\sim}16^{\circ}C$, the dissolved amount of ozone was applied more than 5.0 mg/L, the reaction time was determined as an optimal condition, such as $30{\sim}40$ minutes, and the segregation membrane in the same reactor was determined for acquire water drinking of large quantity using a pore size of $0.45{\mu}m$ M/F membrane.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.309-315
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• 2005

In this study, the bacterial regrowth characteristics in drinking water were investigated for various nutrient concentrations and forms using improved BRP method as a traditional approach and specific regrowth rate as a new index. The results of bacterial regrowth potential for glucose and $NH_4^+-N$, which was evaluated by BRP method as a traditional index, appeared to be higher relative to that of acetate or humic acids as carbon source and $NO_2^--N\;or\;NO_3^--N$ as nitrogen sources, respectively. The results obtained by specific regrowth rate as a new index were similar to that of BRP method with respect to the nutrient conditions examined in this study; i.e., the specific regrowth rate for glucose(ranged from 0.005 to $0.082\;hr^{-1}$) was feater than that acetate and humic acids(ranged from 0.005 to $0.068\;hr^{-1}$ and from 0.005 to $0.008\;hr^{-1}$, respectively). And specific regrowth rate for $NH_4^+-N$ (ranged from 0.008 to $0.072\;hr^{-1}$) was feater than that $NO_2^--N\;and\;NO_3^--N$ (ranged from 0.008 to $0.055\;hr^{-1}$ and from 0.008 to $0.059\;hr^{-1}$, respectively). Therefore, specific regrowth rate can be applied in order to evaluate the bacterial regrowth potential in drinking water.

• Science of Emotion and Sensibility
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• v.19 no.4
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• pp.55-70
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• 2016

It has been suggested that few studies were completed on psychological aspect of coffee drinking behavior though coffee researches have been mainly focused on marketing or business purposes. In this study, fifteen university students were participated to a group interview for concept mapping analysis asking about their meaning and purpose of coffee drinking behavior. Sixty nine statements were extracted from the interview, and categorized into seven clusters using multi dimensional scaling analysis and hierarchical cluster analysis. Seven clusters were Personal method of getting the desired physical effect, As a method of social activities, Method to get psychological consolation, Drink for spending time and using space, Habitual drink and use of caffeine's effect, Enjoying coffee's various characteristic and attraction, and Enjoying coffee's various characteristic and attraction. Two factors were identified based on these clusters such as internal-external motivation to drink coffee and emotional-physical effect of coffee. Participants ranked their priority of those clusters; the cluster of "Drink for spending time and using space" was first ranked. Limitations and suggestions for future research were also discussed.

• Analytical Science and Technology
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• v.29 no.1
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• pp.29-34
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• 2016

This study explores the means by which MX can be effectively extracted from chlorinated water 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a potent mutagen commonly found in chlorinated drinking water at concentrations of up to a few hundred ng/L, was quantitatively determined using sample enrichment followed by liquid-liquid extraction (LLE), derivatization to methylated form, and analysis with GC-MS. A 4-L water sample was enriched to a concentration of 0.4 L using a vacuum rotary evaporator at 30 ℃. MX in the water was extracted using ethyl acetate (100 mL × 2) as a solvent and MX in the extract was methylated with 10 % H₂SO₄ in methanol. MX was recovered at a rate of 73.8 %, which was higher than that (38.1 %) for the resin adsorption method. The limit of quantification and repeatability (as relative standard deviation) were estimated to be 10 ng/L and 2.2 %, respectively. This result suggested that LLE can be used for the determination of MX in chlorinated water as an alternative to more time-consuming resin adsorption method.

• Journal of Environmental Health Sciences
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• v.42 no.3
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• pp.189-195
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• 2016

Objectives: To ensure the microbiological safety of groundwater, it was confirmed whether waterborne pathogenic bacteria in groundwater samples tested positive for total coliforms in the Chungcheongnam-do Province region. Methods: Total colony counts, total coliforms and fecal coliforms were tested according to the process mandated by the drinking water quality testing standards of Korea. DNA was extracted from the samples, tested positive for total coliforms, and then subjected to real-time PCR to detect waterborne pathogenic bacteria. Results: A total of 115 samples were inadequate for drinking water. Thirty-one cases (27%) showed positive for fecal coliforms and nine cases (7.8%) showed total colony counts exceeding drinking water standards. Twenty-seven cases (23.5%) showed three items (total colony counts, total coliforms and fecal coliforms). Using the real-time PCR method, waterborne pathogens were detected in 57 cases (49.6%) in 115 samples. Seventy-eight cases of waterborne pathogenic bacteria were detected (including duplications): 27 cases of pathogenic E. coli (EPEC (19), ETEC (5), EHEC (1), EAEC (1) and EIEC (1)); 45 of Bacillus cereus; two of Yersinia spp.; two of Salmonella spp.; one of Staphylococcus aureus; one of Clostridium perfringens. Conclusion: The real-time PCR method can offer rapid and accurate detection of waterborne pathogenic bacteria. Therefore, this assay could be an alternative to conventional culture methods and can further ensure the microbiological safety of groundwater.

• The Journal of the Convergence on Culture Technology
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• v.8 no.4
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• pp.107-114
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• 2022

The purpose of this study is to identify the prevalence of impaired fasting glucose among non-diabetic middle-aged men in Korea and to identify factors related to impaired fasting glucose. The research method is a descriptive research study using data of 545 men aged 40-64 who participated in the 8th Korean Health and Nutrition Examination Survey(KHANES) in the second year(2020). For data analysis, frequency and percentage, mean and standard deviation, Rao-Scott 𝛘², t-test, and logistic regression analysis were performed using the complex sample analysis method of SPSS/WIN 23.0 program. The results of this study showed that the prevalence of impaired fasting glucose was 44.77%, and the frequency of drinking(OR=1.531, 95% CI: 1.01-2.33) and triglycerides(OR=1.002, 95% CI: 1.00-1.01) were significantly related factors for impaired fasting glucose. Therefore, it is necessary to develop a program for the prevention and management of impaired fasting glucose in middle-aged men, and this program should include drinking habits and triglycerides management strategies.