• Environmental Engineering Research
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• v.19 no.1
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• pp.47-57
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• 2014

The aim of this paper was to study the effect of five different waste combinations (C/N 15, C/N 20, C/N 25, C/N 30, and control) of sewage sludge coupled with sawdust and cattle manure in a pilot scale rotary drum reactor, during 20 days of the composting process. Our results showed that C/N 30 possesses a higher temperature regime with higher % reduction in moisture content, total organic carbon, soluble biochemical oxygen demand and chemical oxygen demand; and higher % gain in total nitrogen and phosphorus at the end of the composting period implying the total amount of biodegradable organic material is stabilized. In addition, $CO_2$ evolution and oxygen uptake rate decreased during the process, reflecting the stable behavior of the final compost. A Solvita maturity index of 8 indicated that the compost was stable and ready for usage as a soil conditioner. The results indicated that composting can be an alternate technology for the management of sewage sludge disposal.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.816-826
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• 1998

The effects of rice bran oil on the characteristics of performance and exhaust emissions have been experimentally examined by a single cylinder four cycle direct injection water-cooled and agricultural diesel engine operating at several loads and speeds. The experiments are conducted with light oil blends of rice bran with light oil and rice bran oil as a fuel. The fuel injection timing if fixed to $22^{\circ}$ BTDC regardless of fuel type engine loads and speeds. Any oxygen is not included in light oil while the oxygen contents of 10.7% are included in rice bran oil. The lower calorific value of rice bran oil is less than light oil and the viscosity is very high compared with light oil. In pre-sent study it is found that these major differences of chemical and physical properties control the combustion parameters that affect the performance and exhaust emissions of diesel engines using a rice bran oil as fuels.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.390-395
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• 2003

The effect of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rate are experimentally investigated by using an once-through boiler with FGR system. The purpose of this study is to develop the FGR control system for reducing NOx in a boiler. Intake and exhaust oxygen concentrations, and equivalence ratio are applied to discuss the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that NOx emissions are decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.155-162
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• 2015

Abalone (Haliotis discus hannai) is a shellfish that feeds on kelp and, as a product, it can often achieve a high market value. However, the dissolved oxygen (DO) levels in coastal waters in Korea have been negatively impacted by pollution from many anthropogenic sources. Herein, a computational fluid dynamics (CFD) software package was used to analyze the distribution of the DO concentration within an abalone containment structure. A finite volume approach was used to solve the Reynolds-averaged Navier-Stokes equations combined with a $k-{\varepsilon}$ turbulence model to describe the flow. The distribution of DO was determined within the control volume domain, and the transport equations of the pollutants were interpreted using a CFD model. The CFD analysis revealed that more than 60% and 30% of the relative oxygen concentration in one and two containers, respectively, was maintained when the flow acts along the six sheets of polyethylene plates. Therefore, it is clear that the abalone plate shelters should be placed parallel to the flow.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.145-149
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• 1978

This experiments were conducted to find out the physiological characteristics of lowland weed for physiological control. Temperature, moisture, light, oxygen. carbon dioxide and soil texture effect on germination and sprouting of weed seed. But this research was conducted to know the relationship between oxygen concentration and germination on 7 species weed.

• Journal of Surface Science and Engineering
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• v.32 no.6
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• pp.671-676
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• 1999

ITO (indium tin oxide) thin films on PET (polyethylene terephthalate) substrate have been deposited by a dc reactive magnetron sputtering without heat treatments such as substrate heater and post heat treatment. Each sputtering parameter during the sputtering deposition is an important factor for the high quality of ITO thin films deposited on polymeric substrate. Particularly, the material, electrical and optical properties of as-deposited ITO oxide films are dominated by the ratio of oxygen partial pressure. As the experimental results, the excellent ITO films are prepared on PET substrate at the operating conditions as follows : operating pressure of 5 mTorr, target-substrate distance of 45mm, do power of 20~30W, and oxygen gas ratio of 10%. The optical transmittance is above 80% at 550 nm, and the sheet resistance and resistivity of films are 24 Ω/square and $1.5\times$10$^{-3}$ Ωcm, respectively.

• Journal of the Korean Chemical Society
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• v.23 no.6
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• pp.396-401
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• 1979

Measuring the reaction rate of bilirubin and oxodipyrromethenes with singlet oxygen, we have found oxodipyrromethenes to be better singlet oxygen trapping agents than diphenyl-isobenzofuran, the best such agent known so far. The photooxygenation rates of bilirubin and the model compounds, oxodipyrromethenes approached the diffusion control threshold. A new oxodipyrromethene is synthesized.

• Journal of ILASS-Korea
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• v.8 no.4
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• pp.24-30
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• 2003

This paper presents the characteristics of lifted height and flame length from non-premixed jet flames in highly preheated air to investigate the detail combustion mechanism in the gas turbine or HCCI engine, etc. Special attention was paid to the effect of preheated air temperature, oxygen concentration and fuel injection flow rate on flame length and lifted hight. By using highly preheated air, stable flames were formed even in low oxygen concentration condition. The lifted height increased with decreasing preheated air temperature, where the flame length showed opposed phenomena. The flamelet model, which is thought to have very thin flamelet, is difficult to applicable to the present flame conditions which is formed In low oxygen concentration in highly preheated air.

• YAKHAK HOEJI
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• v.51 no.1
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• pp.75-82
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• 2007

Reactive oxygen species (ROS) are produced in the metabolic process of oxygen in cells. The superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in cells systemize the antioxidant enzymes to control the oxidative stress. Genistein is one of the isoflavonoids, and its role in controlling cellular oxidative stress is presently the active issue at question. In this study; we analyzed genistein-induced survival rates of the CHO-K1 cells, activities of antioxidant enzymes, ROS levels, and expression levels of antioxidant enzyme genes in order to investigate the effect of genistein on cellular ROS production and antioxidative systems in CHO-K1 cells. As results, the survival rate of cells was decreased as the dose of genistein increases (12.5${\sim}$200 ${\mu}$M). Genistein increased cellular ROS levels, while it reduced total SOD activities and the expression of CuZnSOD. In conclusion, we suggest that genistein may induce oxidative stress via down-regulation of SOD.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.4
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• pp.980-984
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• 2006

In order to examine the effect of oxygen free radicals on the vascular endothelial cells, cell viability was measured by XTT assay after bovine pulmonary vascular endothelial cell line(BPVEC) was treated only with hydrogen peroxide. In addition, the antioxidant effect of allopurinol on cells treated with hydrogen peroxide was examined by colormetric assay. in this study, the BPVEC treated with hydrogen peroxide showed the significantly decreased cell viability compared with control. Whereas, the viability of cells treated with hydrogen peroxide and allopurinol has significantly increased when compared with that of cells treated only with hydrogen peroxide. These results suggested that hydrogen peroxide, one of the oxygen free radicals showed cytotoxic effect and allopurinol has protective effect on oxygen free radical-induced cytotoxicity.