• Nuclear Engineering and Technology
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• 제46권6호
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• pp.797-802
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• 2014

This study investigated the thermal hydraulic issues in the Containment Filtered Venting System (CFVS) for a long operating time using the MELCOR computer code. The modeling of the CFVS, including the models for pool scrubbing and the filter, was added to the input file for the OPR-1000, and a Station Blackout (SBO) was chosen as an accident scenario. Although depressurization in the containment building as a primary objective of the CFVS was successful, the decontamination feature by scrubbing and filtering in the CFVS for a long operating time could fail by the continuous evaporation of the scrubbing solution. After the operation of the CFVS, the atmosphere temperature in the CFVS became slightly above the water saturation temperature owing to the release of an amount of steam with high temperature from the containment building to the scrubbing solution. Reduced pipe diameters at the inlet and outlet of the CFVS vessel mitigated the evaporation of scrubbing water by controlling the amount of high-temperature steam and the water saturation temperature.

• Environmental Engineering Research
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• 제24권3호
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• pp.456-462
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• 2019

Hydrocarbon contamination is among the most challenging problems in soil remediation. Electrokinetic method can be a promising method to remediate hydrocarbon-contaminated soils. Electrokinetic method consists of different transport phenomena including electro-migration, electrophoresis, and electroosmotic flow. Electroosmotic flow is the main transport phenomenon for hydrocarbon removal in soil porous media. However, the main component of hydrocarbons is the hydrophobic organic which indicates low water solubility; therefore, it makes the electroosmotic flow less effective. The objective of the present study is to enhance electrokinetic remediation of diesel-contaminated silty sand by increasing the solubility of the hydrocarbons in the soil and then increase the efficiency. For this purpose, sodium dodecyl sulfate (SDS) was used as a catholyte. In this content, SDS 0.05 M was used as catholyte and $Na_2SO_4$ 0.1 M was used as an anolyte. Low (1 V/cm) and high (2 V/cm) voltage gradients were used in periodic and continuous forms. The best removal efficiency was observed for high voltage gradient (2 V/cm) in a periodic form, which was 63.86. This result showed that a combination of periodic voltage application in addition to the employment of SDS is an effective method for hydrocarbon removal from low permeable sand.

• Journal of Preventive Medicine and Public Health
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• 제39권1호
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• pp.67-73
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• 2006

Objective: This study was conducted to investigate the relationship between the intention of smoking and its related factors in high school students. Methods: Our study subjects were 1,203 high school students who resided in one city and in one county region. We conducted a self-administered questionnaire survey from June 7 to June 19, 2004. Both the decisional balance and temptation inventory showed high reliability estimates. We provided good fit for the 12-item decisional balance inventory and the 10-item temptation inventory by using a confirmatory factor analysis. We also used multiple logistic regression analysis to identify the major contributing factors for the intention to start smoking. Results: On the univariate analysis, the subjects who were female, the 2nd and 3rd grade students, the students in vocational high school, the ex-drinkers or current drinkers, and ex-smokers were found to be significantly more distributed in the groups with intention to start smoking. Except for the concept of the cons, the group with intention to start smoking showed significantly higher standardized T scores for the 7 concepts of decisional balance and temptations. On the multiple logistic regression analysis, the females, the 2nd and 3rd grade students, the students in vocational high school, the experience of cigarette smoking and low T score of the cons were significantly related to the intention to start smoking. Conclusions: The intention to start smoking in high school students was affected by various factors such as gender, the school grade and the experience of smoking. Therefore, further research should be conducted for providing the essential data for developing a brief instrument for selecting the groups with intention of starting smoking among adolescents.

• Asian-Australasian Journal of Animal Sciences
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• 제19권6호
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• pp.865-871
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• 2006

Signs of dental discolouration, difficulty in mastication, bony exostosis and debility were observed in cattle from Qingtongxia Ningxia, China where fluoride concentration in drinking water, soil, fodder, serum, bone, teeth, haircoat and urine were significantly higher than the corresponding health site. The problem of fluorosis in beef cattle is attributable to water containing toxic levels of fluoride. The objective of this paper was therefore to evaluate the influence of fluoride on erythrocyte parameters in cattle under high fluoride and low selenium conditions, as well as the protective efficacy of selenium exposure in feedstuff for bovine endemic fluorosis. Sixteen 6 to 7 year-old high fluoride beef cattle were randomly allotted into two groups each with eight cows: high fluoride control group, and supplemented with 0.25 mg/kg selenium per day for 83 days respectively. In addition, eight 6 to 7 year-old normal control beef cattle were selected from a non-high fluoride site. Blood samples were collected on day 0, 30 and 83 for erythrocyte parameters analysis and scanning electronic microscopy. The results indicated that erythrocytes, hemoglobin, packed cell volume values and $Na^+-K^+$ ATPase activity from affected cattle on the high fluoride site were significantly reduced during the period as compared with the corresponding samples of normal control cattle, a great number of echinocytes were present in peripheral blood, and subsequent anaemia. However, affected cattle exposed to selenium revealed increasable erythrocyte parameters, the extent of elevation in these values being dependent on the duration of supplementation with selenium. These findings suggest that fluoride exposure can cause erythrocyte damage, whereas selenium supplementation can antagonize fluoride-induced generation of free radicals and cumulative effects of lipid peroxidation in erythrocytes. Selenium supplementation may help to alleviate the possible hazards associated with bovine endemic fluorosis.

• Biomolecules & Therapeutics
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• 제24권1호
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• pp.94-98
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• 2016

The objective of the present study was to elucidate the effect of bisphosphonates, anti-osteoporosis agents, on glucose uptake in retinal capillary endothelial cells under normal and high glucose conditions. The change of glucose uptake by pre-treatment of bisphosphonates at the inner blood-retinal barrier (iBRB) was determined by measuring cellular uptake of $[^3H]3$-O-methyl glucose (3-OMG) using a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB cells) under normal and high glucose conditions. $[^3H]3$-OMG uptake was inhibited by simultaneous treatment of unlabeled D-glucose and 3-OMG as well as glucose transport inhibitor, cytochalasin B. On the other hand, simultaneous treatment of alendronate or pamidronate had no significant inhibitory effect on $[^3H]3$-OMG uptake by TR-iBRB cells. Under high glucose condition of TR-iBRB cells, $[^3H]3$-OMG uptake was increased at 48 h. However, $[^3H]3$-OMG uptake was decreased significantly by pre-treatment of alendronate or pamidronate compared with the values for normal and high glucose conditions. Moreover, geranylgeraniol (GGOH), a mevalonate pathway intermediate, increased the uptake of $[^3H]3$-OMG reduced by bisphosphonates pre-treatment. But, pre-treatment of histamine did not show significant inhibition of $[^3H]3$-OMG uptake. The glucose uptake may be down regulated by inhibiting the mevalonate pathway with pre-treatment of bisphosphonates in TR-iBRB cells at high glucose condition.

• 한국주조공학회지
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• 제20권5호
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• pp.300-306
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• 2000

The objective of this work was to investigate the effects of SiC particle size(50, 100 ${\mu}m$) and additional elements such as Si, Cu and Ti on aging behavior in Al-5Mg-X(Si,Cu,Ti)/SiCp composites fabricated by pressureless infiltration method using hardness and wear test, scanning electron microscopy(SEM) and differential scanning calorimetry(DSC). The peak aging time in Al-5Mg-X(Si, Cu, Ti)/SiCp(50, 100 ${\mu}m$) composites is shorter than Al-5Mg-0.3Si alloy.The peak aging time of 50 ${\mu}m$ SiC particle reinforced Al-5Mg-X(Si,Cu,Ti) composites is shorter than those of 100 ${\mu}m$ SiC particle reinforced of Al-5Mg-X(Si,Cu,Ti) composites. The Al-5Mg-0.3Si-0.1Cu-0.1Ti/SiCp(50 ${\mu}m$) composites aged at $180^{\circ}C$ has higher hardness and better wear resistance than any other aged composite.The aging effect is promoted by the addition of Si and Cu in Al-5Mg/SiCp composites, so the wear resistance of Al-5Mg/SiCp composites with Si and Cu elements is enhanced by the aging treatment.

• 한국환경보건학회지
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• 제41권5호
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• pp.305-313
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• 2015

Objectives: The objective of this study is to identify toxicants causing acute toxicity in effluents from the aluminum rolling industry that violate the discharge limits in Korea. Methods: Whole effluent toxicity tests (WET) were conducted on effluent discharged from the aluminum rolling industry following the US EPA WET test methods. We collected effluent samples three times and evaluated acute toxicity by using Daphnia magna. We employed toxicity identification evaluation (TIE) procedures to identify toxicants causing toxicity in the effluent. Results: No specific chemical groups were identified in the seven different manipulations applied to the of wastewater effluent samples showing 1.3 toxic units (TU) according to the TIE phase I procedures. Water quality parameters for water hardness, electric conductivity and heavy metals (Mn) were 4,322 mg/l as $CaCO_3$, 11.39 mS/cm, and $5,551{\mu}g/l$, respectively. Considering water hardness and reference toxicity, high concentrations of Mn can be disqualified from the causative toxicants. Consequently, high ionic concentrations of $Na^+$(1,648 mg/l), $Ca^{2+}$(1,048 mg/l), $Mg^{2+}$(1,428 mg/l) and $SO_4{^{2-}}$(7,472 mg/l) were identified to be causative toxicants. Water hardness and electric conductivity exceed the $EC_{50}$ value obtained by biological toxicity tests using Daphnia magna. Conclusion: According to TIE procedures, high salt concentration is determined to be a major toxicant in the effluent of agro-industrial wastewater treatment plants receiving wastewater from the aluminum rolling industry.

• Korean Journal of Radiology
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• 제21권1호
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• pp.108-116
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• 2020

Objective: To investigate the concordance of three international guidelines: the Korean Thyroid Association/Korean Society of Thyroid Radiology, American Thyroid Association, and American College of Radiology for thyroid nodules classified by ultrasonography (US) and the diagnostic performance of simulated size criteria for malignant biopsies. Materials and Methods: A total of 2586 thyroid nodules (≥ 1 cm) were collected from two multicenter study datasets. The classifications of the thyroid nodules were based on three different guidelines according to US categories for malignancy risk, and the concordance rate between the different guidelines was calculated for the classified nodules. In addition, the diagnostic performance of criteria related to four different simulated biopsy sizes was evaluated. Results: The concordance rate of nodules classified as high- or intermediate-suspicion was high (84.1-100%), but low-suspicion or mildly-suspicious nodules exhibited relatively low concordance (63.8-83.8%) between the three guidelines. The differences in sensitivity, specificity, and accuracy between the guidelines were 0.7-19.8%, 0-40.9%, and 0.1-30.5%, respectively, when the original biopsy criteria were applied. The differences decreased to 0-5.9%, 0-10.9%, and 0.1-8.2%, respectively, when simulated, similar biopsy size criteria were applied. The unnecessary biopsy rate calculated with the original criteria (0-33.8%), decreased with the simulated biopsy size criteria (0-8.7%). Conclusion: We found a high concordance between the three guidelines for high- or intermediate-suspicion nodules, and the diagnostic performance of the biopsy criteria was approximately equivalent for each simulated size criterion. The difference in diagnostic performance between the three guidelines is mostly influenced by the various size thresholds for biopsies.

• 지질공학
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• 제20권1호
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• pp.1-12
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• 2010

본 연구에서는 인천 해안 LPG공동의 수리화학적 안정성을 평가하기 위해 공동 유출수 및 주변 지하수에 대한 수리지구화학적 및 미생물학적 특성을 평가하였다. 수질특성을 파악하기 위하여 2007년 2월, 5월, 8월, 10월에 걸쳐 시료채취 및 수질분석을 실시하였다. 프로판공동 지하수의 경우 pH는 8.1~12.4의 높은 값을 보였으며 이는 공동건설 및 관측정설치에 사용된 시멘트 그라우팅 물질의 용해영향으로 사료된다. 전기전도도는 시료채취 시기별로 큰 차이를 보였으며, 음의 산화환원전위는 유출수 및 지하수가 환원환경에 있음을 지시하였다. 수질분석결과 유출수 및 지하수의 수질유형은 모두 Na-Cl type으로 나타났으며 이는 해수의 영향으로 판단된다. 호기성세균, 혐기성세균, 점액질세균, 황산환원세균 모두 500 CFU/mL 미만으로 낮은 값을 보였으며 급격한 미생물 성장은 관찰되지 않았다. 현재로선 공동 운영에 지장을 주는 특이적 수리화학적 현상이 발견되지는 않았으나 지속적인 모니터링이 필요하다.

• 한국약용작물학회지
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• 제26권5호
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• pp.417-429
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• 2018

Background: The objective of this study was to make colloidal dispersions of the active compounds of radix of Angelica gigas Nakai that could be charaterized as nano-composites using hot melt extrusion (HME). Food grade hydrophilic polymer matrices were used to disperse these compound in aqueous media. Methods and Results: Extrudate solid formulations (ESFs) mediated by various HPMCs (hydroxypropyl methylcelluloses) and Na-Alg polymers made from ultrafine powder of the radix of Angelica gigas Nakai were developed through a physical crosslink method (HME) using an ionization agent (treatment with acetic acid) and different food grade polymers [HPMCs, such as HP55, CN40H, AN6 and sodium alignate (Na-Alg)]. X-ray powder diffraction (XRD) analysis confirmed the amorphization of crystal compounds in the HP55-mediated extrudate solid formulation (HP55-ESF). Differential scanning calorimetry (DSC) analysis indicated a lower enthalpy (${\Delta}H=10.62J/g$) of glass transition temperature (Tg) in the HP55-ESF than in the other formulations. Infrared fourier transform spectroscopy (FT-IR) revealed that new functional groups were produced in the HP55-ESF. The content of phenolic compounds, flavonoid (including decursin and decursinol angelate) content, and antioxidant activity increased by 5, 10, and 2 times in the HP55-ESF, respectively. The production of water soluble (61.5%) nano-sized (323 nm) particles was achieved in the HP55-ESF. Conclusions: Nano-composites were developed herein utilizing melt-extruded solid dispersion technology, including food grade polymer enhanced nano dispersion (< 500 nm) of active compounds from the radix of Angelica gigas Nakai with enhanced solubility and bioavailability. These nano-composites of the radix of Angelica gigas Nakai can be developed and marketed as products with high therapeutic performance.