• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.123-128
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• 2016

The effect of propeller surface roughness condition on ship performance is very significant even the influence of fouling on propeller performance is not well established compared to biofouling on the hull surface. In present study, predictions of open water efficiency of propeller are made for three different fouling conditions, and its application is given for the 7m full-scale propeller of a medium-size tanker in open water condition. The numerical predictions of propeller efficiency loss due to fouling are based on the results from laboratory-scale drag measurements and boundary layer similarity law analysis presented in Schultz (2007) together with an in-house unsteady lifting surface code which is an appropriate tool to predict the effect of propeller surface roughness on propeller performance. The results of this study indicate that the subject propeller with the small calcareous fouling ($k_s=0.001$) can lead to as high as 15 % loss at the propeller operating condition (J=0.5) and the loss of propeller efficiency due to fouling should be evaluated while the ship is operating.

• Journal of Pharmaceutical Investigation
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• v.25 no.3
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• pp.177-184
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• 1995

In order to formulate an aqueous topical preparation of epidermal growth factor(EGF) for the treatment of open wound and bum, the stability of EGF in aqueous vehicles containing various stabilizers was evaluated and the pharmacological activity of gel preparations formulated with poloxamer 407 was determined with wound model. Various additives, which are known as potent stabilizers for proteins and polypeptides so far, were used to increase the stability of EGF in aqueous vehicles. The contents of EGF in the vehicles containing stabilizers were determined with an HPLC method after the storage at $37^{\circ}C$. EGF was more stable in ultrapure water than RO water or saline. All the additives studied resulted in deleterious effects on EGF stability. Therefore, it was speculated that any additives or impurities in the vehicle made EGF unstable. However, nitrogen purge of solution increased the stability of EGF in aqueous vehicles. The aqueous topical preparations of EGF were formulated with poloxamer 407 as a gel base in saline. Gelatin or amastatin was employed as a protease inhibitor. The pharmacological effect of EGF gel was studied with open wound model in mice. EGF preparations, made of oleaginous base or poloxamer gel base, showed significant healing effect compared to the control group(p<0.05). The addition of protease inhibitor in poloxamer 407 gel resulted in significant healing effect compared to the gel without it(p<0.05). Body weights of mice treated with EGF preparation were increased at the first day after the formation of open wound, while those of the control group were decreased. The EGF gel made of poloxamer 407 containing a pretense inhibitor would be a promising aqueous topical preparation for EGF.

• Journal of the Korean Institute of Gas
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• v.6 no.1 s.17
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• pp.92-97
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• 2002

This paper was studied on corrosion characteristics of gas absorption refrigeration & hot water system using $LiBr-H_2O$ working fluids. In the $62\%$ lithium bromide solution at $60^{\circ}C$, polarization test of Cu, $10\%$ cupronickel($90-10\%$ Cu-Ni) and $30\%$ cupronickel($70-30\%$ Cu-Ni) tube was carried out. And polarization behavior, polarization resistance characteristics, open circuit potential, anodic polarization of heat exchanger tube for gas absorption refrigeration & hot water system were considered. The main results are as following: 1) Polarization resistance of heat exchange tubes appears high in order of $30\%$ cupronickel tube > $10\%$ cupronickel tube > Cu tube. B) Open circuit potential of cupronickel tube is more noble than that of Cu tube, and corrosion current density of cupronickel is controlled than Cu tube. 3) Potential of passive region of $30\%$ cupronickel tube is more wide than that of $10\%$ cupronickel tube, and the passivation critical current of $30\%$ cupronickel tube is lower than that of $10\%$ cupronickel tube.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.500-507
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• 2004

This study was conducted to evaluate the equity of the flow distribution from rapid mixing basin to the flocculation basins. Also, several types of inlet structures of the open channel affecting the flow pattern and distribution trend were studied using Computational Fluid Dynamics (CFD) simulation. For investigating the factual phenomena in distribution channel, we selected a certain domestic water treatment plant with capacity of $361,000m^3/d$. From the measurements of flow discharge, it is investigated that this existing inlet geometry resulted in significant inequitable distribution. The both largest deviations in the basins and rows were over 10%. In order to reduce the these deviation, this study suggested installing a baffle against the influent, and showed the effectiveness which the largest deviation was less than 3%. Also, it was concluded that the existing design method of open channel could be improved by three-dimensional hydrodynamic analysis for optimizing the even flow.

• Journal of Fisheries and Marine Sciences Education
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• v.12 no.2
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• pp.164-175
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• 2000

Port facilities and marine structures used in marine environment were encountered to corrosion damages because of the influence of Cl-. Generally, to protect these accidents, anti-corrosion paint and epoxy coating have been used. But they were still remained erosion-corrosion damage like impingement erosion, cavitation erosion and deposit attack. It is necessary to develope the new composite lining material in order to protective those corrosion damages. In this paper, polyester glass flake, vinylester glass flake lining and epoxy coating for SS400 were investigated by the electrochemical polarization test and the impingement-cavitation erosion test for corrosion behaviour under the sea water. The main results obtained are as follows ; 1) Epoxy coating appear potentiodynamic polarization behaviour, but polyester glass flake and vinylester glass flake lining do not appear potentiodynamic polarization behaviour. 2) Open circuit potential of polyester glass flake lining is more noble than that of epoxy coating and corrosion current density of polyester glass flake lining is less drained than that of epoxy coating in sea water. 3) Open circuit potential of vinylester glass flake lining is more noble than that of polyester glass flake lining and corrosion current density of vinylester glass flake lining is less drained than that of polyester glass flake lining in the sea water.

• Journal of Ocean Engineering and Technology
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• v.28 no.4
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• pp.345-350
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• 2014

A special usage impeller pump for ballast water treatment is part of an offshore plant's structure. It has to maintain a high corrosion resistance in an extreme environment, in which it can contact several kinds of aqueous solutions. The duplex stainless steel used in such severe environments is known to have corrosion resistance and excellent mechanical properties. This study estimated the performance of an impeller pump system designed using duplex stainless steel through a computational fluid dynamics analysis. As a result, it was determined that the pressure drop increases and the impeller performance is lowered if the equivalent roughness is enlarged. The surface precision of the duplex stainless steel must be consistently maintained. If thisis the case, it was determined that the existing STS steel can be substituted for the Duplex stainless steel.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.5
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• pp.571-579
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• 2007

This study was conducted to qualify the equality of the flow distribution from open channel between rapid mixing basin and flocculation basins in a domestic full-scale water treatment plant, and suggest a remedy for improving the equality. In order to evaluate the feasibility of the suggested remedy, computational fluid dynamics (CFD) technique are used, and for verifying the CFD simulation results wet tests were carried out for the pilot scale channel based on geometric similarity. From the results of CFD simulation and wet tests, it was investigated that the modification of hydraulic structure in the distribution channel, which is to install the longitudinal orifice baffle in flow direction, could improve the equality of the flow distribution. Also, in the case that Froude number is relatively small (Froude number <<0.03), the open ratio of orifices on the installed baffle hardly affects the equality of flow distribution.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.869-875
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• 2011

Ministry of Environment has been promoting BTL business of the sewer rehabilitation which continues from 2005 up to now. Sewer rehabilitation is classified into three parts : wastewater pipe rehabilitation, rainwater pipe rehabilitation and drainage equipment rehabilitation. Drainage equipment rehabilitation is that drainage pipe connects wastewater pipe directly without water-purifier. In the drainage equipment construction, it is inevitable to have the damage of ground structures(wall, gate and U drain, etc) when an open excavation method is used. Therefore it is necessary to develop non-excavation method to connect drainage pipe and wastewater pipe like jacking method to avoid the damage of ground structure. This paper has conducted an analysis of the non-excavation method using a boring machine attached to backhoe, which is issued the verification certificate of environmental technology according to the Development of and Support for Environmental Technology Act, article.7. The index set in this analysis was sectionalized to the condition of construction, the grade of drainage pipe, the size of excavated hole, the amount of waste cement concrete and asphalt concrete and the benefit effect compared to open excavation method.

• Journal of Energy Engineering
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• v.27 no.1
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• pp.65-75
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• 2018

The emission of greenhouse gases mainly carbon dioxide and methane is the result of rapid industrialization to meet the demands of ever-growing population. This has resulted in an increase of global temperature which in turn is responsible for severe environmental, social, ecological and economic losses, commonly known as to as 'climate change'. This study attempts to highlight the impacts of climate change mainly focussing on water contamination, sanitation and open defecation in India. The requirement for the instantaneous employment of environment friendly technologies along with improved sanitary system has been discussed. Various other issues which are also linked to climate change that need further management like managing water resources, deterioration in human health, economic losses, modification and successful implementation of policies have been pointed out. Furthermore, stress has been made for the urgent adaptation and rethinking for making strategies along with the involvement of women in order to cop up challenges offered by climate change.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.957-960
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• 2004

From a water-environmental point of view, with a change of understanding and concern about vegetation, it changes that vegetation acts as stability of channel and bed, providing habitats and feed for fauna, and means improving those with appreciation of the beautiful but resistant factor to the flow So, it becomes important concern and study subjects that turbulent structure by vegetation, shear stress and transport as well as roughness and average velocity by vegetation. But from a hydraulic point of view, vegetation causes resistance to the flow and can increase the risk of flooding, Therefore, this thesis concern the flow characteristics in vegetated open channels. According to the experimental results, $z_0$ was on an average $0.4h_p$ in a vegetated open channel. So, the elevation corresponding to zero velocity in a vegetated channel was the middle of roughness element. The limit for logarithmically distributed profile over the roughness element was from $z_0$ to $0.80h_{over}$ for a vegetated channel. Among the existing theory, the method of Kouwen et al.(1969), Haber(1982), and El-Hakim and Salama(1992) except Stephan(2001) gave a very good value compared to the measured velocity profile.