• Journal of Korean Society on Water Environment
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• v.23 no.6
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• pp.837-842
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• 2007

This study was conducted to test the effect of residual Al on plankton community after dissolved air flotation (DAF) application. Growth rate of phytoplankton after DAF application ($0.37day^{-1}$) was about 2 times lower than that before DAF application ($0.70day^{-1}$). Under the condition of addition of nitrogen and phosphorus without light, growth rate phytoplankton in treatment without residual Al increased in difference with showing the negative growth rate in treatment with residual Al. Under the condition of light without addition of nutrient, growth rate of phytoplankton was no noticeable difference between the before and after DAF application. The relatively high settling rate (0.47 m/day) was observed in treatment after DAF application. Although the abundance of rotifer decreased, the abundance of copepod and cladoceran such as Daphnia galeata, Diaphanosoma sp. and Bosmina longirostris with relative higher grazing was no noticeable difference between the before and after DAF application. In the treatments before and after DAF application with zooplankton, growth rate of phytoplankton was $0.41{\pm}0.08day^{-1}$, $0.20{\pm}0.03day^{-1}$, respectively. This difference was in treatment after DAF application similar with those in treatments before and after DAF application without zooplankton. Those indicate that the filter-feeding effect of zooplankton on phytoplankton community may be not changed by residual Al after the DAF application. These results suggest that residual Al after DAF application be to improve water quality by inhibition of growth rate as well as increasing settling rate of phytoplankton.

• Journal of the Korea Institute of Building Construction
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• v.7 no.1 s.23
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• pp.99-106
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• 2007

Water leakage could be caused deterioration of environmental conditions, user condition, reduction of life span and long term safety in underground concrete structure. Many materials and construction method to repair on these problems have been developed, however, it is not proper to successful repair or raise problem of increasing repair cost However, there are many limitations as practical appraisal methods due to different view of reliability for test methods. Because, it was not enough that the technical objectivity could be lack and also application of environmental condition is inadequate. In this paper, we suggest varied test methods divided to appraisal for property of matter, construction, manufacturing, specification and maintenance, friendly environmental condition. It could be more practical as a objective standard considering various angles. In summery, it should be subdivided and differentiated to accomplish proper application and to select proper materials and construction method for repair even if the synthetical condition is very complicated.

• International Journal of Highway Engineering
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• v.15 no.3
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• pp.127-135
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• 2013

PURPOSES : The purpose of this study is development of automatic equipment to measure the road water-reservoir which can be one of factors for road traffic safety inspection and its application to safety analysis. METHODS : The scopes of this study are the examination of the riskiness and location of road water-reservoir through literature review, development of appropriate sensor and automatic equipment to survey the road water-reservoir and evaluation of field application. RESULTS: The laser lighting and IR camera were selected to develop the equipment. It was found from the field calibration that there is a high correlation between rutting and road water-reservoir and road water-reservoir caused by rutting can be correctly calculated. About 20.2km of national highway were inspected for case study and field application. It was found from correlation of traffic incident that 2.08km of the latent length for water-reservoir which is related to 12 traffic incidents were analyzed. CONCLUSIONS : This technique can be utilized evaluation method for road condition such as road water-reservoir for conventional evaluation system such as road traffic safety assessment and safety analysis and it can be use to new evaluation system to apply various road condition and traffic condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.362-365
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• 1984

Application of phosphate and silicate at the seed bed stage of rice seedlings was investigated to improve nutritional condition and rooting capability at low temperature. The amounts of applied phosphate were 15kg/10a with or without 200 kg/10a of silicate, and 30 kg/10a without silicate. Seeding dates were March 31, April 9 and April 19. The dry weight of the seedlings seeded earlier date under low temperature was lower than that of the seedlings seeded later dates. The application of phosphate and silicate increased the dry weight of newly developed roots after trasplanting, and increased the number of tillers. Therefore, heavy application of phosphate and silicate is recommendable to improve the predisposition of the rice seedlings grown under the low temperature condition for early transplanting.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.695-702
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• 2002

Shotcrete (or Sprayed concrete) has been used as an important support material in New Austrian Tunnelling Method (NATM). Since the mid of 1990, permanent shotcrete tunnel linings such as Single-shell, NMT (Norwegian Method of Tunnelling) has been constructed in many countries for reducing the construction time and lowing construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of permanent shotcrcte linings, high performance shotcrete providing high strength, high durability, better pumpability has to be developed in advance as an integral component. This paper presents the Ideas and first experimental attempts to increase early strength and bond strength of wet-mixed Steel Fiber Reinforced Shotcrete(SFRS) in sump water condition. In order to increase early strength, a new approach using high-early strength cement with liquid alkali-free accelerator has been investigated From the results, wet-mix SFRS with high-early strength cement and alkali-free accelerator exhibited excellent early strength improvement compared to the ordinary portland content and good bond strength even under sump water condition.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.402-406
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• 1995

The purpose of this paper is to decrease shotcrete rebound losses and to produce economic effectiveness at the same time in construction. The mechanical properties and quick acceleration of various shoterete mixes were analyzed, which were intuenced by several accelerators and their amouts used. And the application and construction in the felds were evaluated. The shotcrete rebounds relied on the condition of construction rather than on the quality of materials, but it is found that the decreasing of the cost and time in shotcreting under the same condition was based on the rebounds which were affected by the accelerating capability of the accelerators. The application of the accelerator was limited by the condition of tunnel construction ; such as ground water, anti-corrosive, or anti-chemistry. It is important to choose a proper accelerator. Therefore, it is necessary that better accelerators which satisfly mechanical characteristics and economy are developed. Optimal working conditions should be announced to the workers and workers' skill be improved in the shotcrete construction feld as well.

• Journal of Industrial Technology
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• v.24 no.B
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• pp.123-131
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• 2004

The existing of developed scour Equation have a very different value by boundary condition, hydraulic condition and bed condition. Therefore it may give rise to a serious trouble if it make a wrong application of the scour Equation. So this research of purpose is the predicting of scour depths, the method is that analysis river of feature and hydrauric feature for river in kangwondo young-seo region. And hydrauric model experiment of Scour phenomenon execute after the existing of calculate scour depths equation analysis sensitivity, assort a practical.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.1
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• pp.16-22
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• 2003

This paper presents an application of an impedance boundary condition to 3D vector finite element analysis of a multi-port cylidrical microwave cavity using Snell's law. Computing memory benefits and computing time reduction are obtained from this method compared with the conventional finite element method(FEM). To verify the method, a high permittivity scatterer in free space is analyzed and compared with the results of conventional (FEM). In addition, this method has been analyzed several types of cavities, including water load, to demonstrate the validity and accuracy of the program.

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.2
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• pp.44-51
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• 1993

Here is represented a vortex panel method to evaluate the performance characteristics of the 2-dimensional turbomachinery with circular arc blades or logarithmic blades. The present method is characterized by distributing small consecutive panels of linearly varing vortex strength satisfying boundary condition at control points and Kutta condition at trailing edge. To confirm the reliability of the present method, experimental result of a 2-D pump impeller of six circular arc blades is compared with the calculated one. As an application of the present method, figures are presented in series showing velocity and pressure distribution between blades.

• Corrosion Science and Technology
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• v.7 no.1
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• pp.61-67
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• 2008

In this paper, electrochemical and microstructural characteristics of nickel-plated Alloy 600 were investigated in order to identify the performance of electroless Ni-plating on Alloy 600 in high-temperature aqueous condition with the comparison of electrolytic nickel-plating. For high temperature corrosion test of nickel-plated Alloy 600, specimens were exposed for 770 hours to typical PWR primary water condition. During the test, open circuit potentials (OCP's) of all specimens were measured using a reference electrode. Also, resistance to flow accelerated corrosion (FAC) test was examined in order to check the durability of plated layers in high-velocity flow environment at high temperature. After exposures to high flow rate aqueous condition, the integrity of surfaces was confirmed by using both scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). For the field application, a remote process for electroless nickel-plating was demonstrated using a plate specimen with narrow gap on a laboratory scale. Finally, a practical seal design was suggested for more convenient application.