• 상하수도학회지
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• 제29권4호
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• pp.519-531
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• 2015

It has been widely accepted that the pressure management of water distribution systems using pressure reducing valves(PRVs) would be an effective method for controlling leakages. A pressure reducing valve (PRV) regulates outlet pressure regardless of fluctuating flow and varying inlet pressure, thereby reducing leakage and mitigating the stress on the water distribution system. However, the operation of a PRV is vulnerable to its mechanical condition and hydraulic operability. In this research, the effect of PRVs installed in water distribution system are evaluated in terms of hydraulic pressure reduction and mechanical performance by analyzing measured pressure data with statistical approach. A statistical approach using the moving average filter and frequency analysis based on fourier transform is presented to detect abnormally operated PRVs that have been densely installed in water distribution system. The result shows that the proposed approach can be a good performance evaluation method by simply measuring pressures for the PRVs.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권1호
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• pp.37-48
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• 1998

Effect of plant hormones on the leaf senescence of mung bean (Phaseolus radiatus) was investigated by measuring the changes of reducing sugar contents and invertase isozyme activities in detached leaves treated with NAA, $GA_3$ or BA. During dark-induced senescence, reducing sugar contents in the detached leaves increased temporarily at 4 d, thereafter decreased rapidly and reached minimum values within 7-14 d. The pattern of soluble acid invertase activity in the senescing leaves kept in the dark was similar to that of reducing sugar accumulation, whereas the activities of alkaline and extracellular invertases were not significantly changed during leaf senescence. Therefore, these results suggest that soluble acid invertase, but not alkaline and extracellular invertases, induces the accumulation of reducing sugar during leaf senescence of mung bean plants. Exogenous NAA application had little or no effect in the increase of soluble acid invertase activity during dark-induced senescence compared to the control. However, exogenous applications of $GA_3$ and BA led to the increase of soluble acid invertase activity in the senescing leaves. Particularly, BA application was very effective in enhancing the activity of soluble acid invertase as well as in delaying chlorophyll breakdown during dark-induced senescence. These results suggest, therefore, that BA regulates the activity of soluble acid invertase, which leads to the accumulation of reducing sugar, and the stability of photosynthetic apparatus to delay leaf senescence.

• 한국미생물·생명공학회지
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• 제27권3호
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• pp.230-235
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• 1999

This study was intended to develop a new rice product by the fermentation of saccharified rice solution using Bifidobacterium and to select an appropriate reducing agent to provide the anaerobic condition for the growth of Bifidobacterium during fermentation. The enhancement of the growth of Bifidobacterium in saccharified rice solution was achieved by the treatment of reducing agents such as ascorbic acid and cysteine. The physical and chemical properties of the fermented product were evaluated, and the effect of the reducing agents were compared between ascorbic acid and cysteine. The fermented product with the addition of ascorbic acid shows the lower pH and the higher titratable acidity comparing the product with the addition of cysteine. This indicated that ascorbic acid was more appropriate reducing agent than cysteine for the fermentation of the saccharified rice solution. The number of viable Bifidobacterium in the fermented product with the addition of ascorbic acid(2.2$\times$108~3.4$\times$108CFU/ml) was greater than that with the addition of cysteine (8$\times$107~2.8$\times$108CFU/ml). Ascorbic acid supplement also contributed better sensory properties, such as flavor, taste and overall acceptibility than cysteine supplement did.

• Journal of Microbiology and Biotechnology
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• 제26권4호
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• pp.757-762
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• 2016

The group of Fe(III) oxide-reducing bacteria includes exoelectrogenic bacteria, and they possess similar properties of transferring electrons to extracellular insoluble-electron acceptors. The exoelectrogenic bacteria can use the anode in microbial fuel cells (MFCs) as the terminal electron acceptor in anaerobic acetate oxidation. In the present study, the anodic community was compared with the community using Fe(III) oxide (ferrihydrite) as the electron acceptor coupled with acetate oxidation. To precisely analyze the structures, the community was established by enrichment cultures using the same inoculum used for the MFCs. High-throughput sequencing of the 16S rRNA gene revealed considerable differences between the structure of the anodic communities and that of the Fe(III) oxide-reducing community. Geobacter species were predominantly detected (>46%) in the anodic communities. In contrast, Pseudomonas (70%) and Desulfosporosinus (16%) were predominant in the Fe(III) oxide-reducing community. These results demonstrated that Geobacter species are the most specialized among Fe(III)-reducing bacteria for electron transfer to the anode in MFCs. In addition, the present study indicates the presence of a novel lineage of bacteria in the genus Pseudomonas that highly prefers ferrihydrite as the terminal electron acceptor in acetate oxidation.

• Asian Pacific Journal of Cancer Prevention
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• 제17권sup1호
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• pp.85-90
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• 2016

Two years after implementation of the graphic health warning intervention in Vietnam, it is very important to evaluate the intervention's potential impact. The objective of this paper was to predict effects of graphic health warnings on cigarette packages, particularly in reducing cigarette demand and smoking-associated deaths in Vietnam. In this study, a discrete choice experiment (DCE) method was used to evaluate the potential impact of graphic tobacco health warnings on smoking demand. To predict the impact of GHWs on reducing premature deaths associated with smoking, we constructed different static models. We adapted the method developed by University of Toronto, Canada and found that GHWs had statistically significant impact on reducing cigarette demand (up to 10.1% through images of lung damage), resulting in an overall decrease of smoking prevalence in Vietnam. We also found that between 428,417- 646,098 premature deaths would be prevented as a result of the GHW intervention. The potential impact of the GHW labels on reducing premature smoking-associated deaths in Vietnam were shown to be stronger among lower socio-economic groups.

• Food Science and Biotechnology
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• 제14권2호
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• pp.212-215
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• 2005

Ethanol crude extracts of wood, bark, leaf, and fruit of Callistenwn citrinus were compared for their antioxidant activities based on DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical-scavenging activity and reducing power. Bark extract showed the most potent radical-scavenging activity and reducing power, showing 94.1 and 0.64% at 25 and $100\;{\mu}g/mL$, respectively. Total phenolic content of the bark extracts (275.0 mg GAE/g) was higher than those of others. Further fractionation of the bark extract using hexane, $CH_2Cl_2$, and EtOAc showed EtOAc fraction had the highest antioxidant activity ($IC_{50}\;6.7\;{\mu}g/mL$) and reducing power (0.82 at $100\;{\mu}g/mL$), with total phenolic content of 611.1 mg GAE/g. Total phenolic contents correlated with antioxidant activity ($R^2\;=\;0.7061$) and reducing power ($R^2\;=\;0.7399$).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.156-157
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• 2017

It is possible in the case of the chemical admixtures for concrete currently being used in actual work sites to omit quality evaluation and replace it with the scores of the admixture manufactures; this can create a problem of decline in reliability in quality on the work site. Therefore this study sought to analyze the degree of influence changes in the solid content rate of lignin- and naphthalene-based water-reducing agents have on the fundamental characteristics of cement mortar. The results showed that in fresh mortar, the flow and amount of air decreases with decrease in the solid content ratio. In hardened mortar, the condensation strength had hardly any effect on the use of lignin-based water-reducing agent, but naphthalene-based water-reducing agent increased with the decrease in the solid content ratio.

• 대한토목학회논문집
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• 제12권3호
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• pp.81-90
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• 1992

고성능감수제를 사용한 콘크리트의 유동성 손실을 저감시키기 위한 연구의 일환으로 시멘트의 종류, 고성능감수제의 종류, 사용방법 및 사용량이 굳지않은 콘크리트의 유동성 손실에 미치는 영향을 파악하기 위하여 시멘트풀, 모르터 및 콘크리트의 유동성 손실과 관련된 실험을 통하여 얻어진 결과에 대하여 고찰하였다. 본 연구결과 고성능감수제의 첨가시기는 시멘트 및 고성능감수제의 종류에 따라 다소 차이가 있으나 30분후 첨가방법이 유동성 손실을 줄이는데 유효하였으며, 대체로 고성능감수제 사용량이 많을수록 유동성 손실이 크게 나타났으며 보통포틀랜드시멘트 콘크리트가 유동성 손실이 가장 크고 플라이애쉬 20% 혼합시멘트 콘크리트에 나프탈린계 고성능감수제를 30분후 첨가한 경우 유동성 손실이 매우 작은 효과가 있었다.

• Fisheries and Aquatic Sciences
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• 제21권10호
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• pp.33.1-33.11
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• 2018

As a process for commercial application, production of reducing sugar, antioxidant, and DNA protective compounds from shrimp-shell powder was investigated in a fed-batch biodegradation using Bacillus cereus EW5. The fed-batch biodegradation was operated in a 5-L bioreactor for 96 h according to three times pulse-feeding strategy. On the basis of the equal working volume (3 L), the fed-batch biodegradation showed a better production of the target compounds than the batch biodegradation, with higher cell density and shortened biodegradation period. The maximum values of the target compounds were 0.297 mg/mL of reducing sugar, 92.35% DPPH radical scavenging activity, 98.16% ABTS radical scavenging activity, and 1.55 reducing power at $A_{700}$, which were approximately 12.1, 3.4, 5.2, and 8.4% enhanced, respectively, compared with those obtained from the batch biodegradation. The fed-batch culture supernatant also showed the enhanced DNA damage inhibition activity than the batch culture supernatant. As a result, the fed-batch biodegradation accompanied by high cell density could produce more useful compounds, enabling an increase in the reutilization value of shrimp-shell waste.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.194-201
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• 2006

Roof-fairing and deflector system have been used on heavy-duty trucks to minimize aerodynamic drag force not only for driving stability of the truck but also for energy saving by reducing the required driving power of the vehicle. In this study, a numerical simulation was carried out to see aerodynamic effect of the drag reducing device on the model vehicle. Drag and lift force generated on the five different models of the drag reducing system were calculated and compared them each other to see which type of device is efficient on the reduction of driving power of the vehicles quantitatively. An experiment has been done to see airflow characteristics on the model vehicles. Airflow patterns around the model vehicles were visualized by smoke generation method to compare the complexity of airflow around drag reducing device. From the results, the deflector systems(Model 5,6) were revealed as a better device for reduction of aerodynamic drag than the roof-fairing systems(Model 2,3,4) on the heavy-duty truck and it can be expected that over 10% of brake power of an engine can be saved on a tractor-trailer by the aerodynamic drag reducing device at normal speed range($80km/h{\sim}$).