• Journal of the Korean Society of Industry Convergence
• /
• v.11 no.1
• /
• pp.11-18
• /
• 2008

After execute quantitative analysis that choose station and compose floodgate quality of water net and use floodgate data and quality of water data analysis target Sign of the cock as 1 dimension access for Non-point pollution source pollution and estimate of Gaeuncheon's at Kyongsangbukdo report to the Throne in this research, presented parameter conclusion notation model (AGNPS) in real condition of our agricultural area through comparison with spot value and result is as following in reply. With result observation and analysis result of the AGNPS model the comparison which it will pay from the hazard which it analyzes 2005, the rainfall thought which is used in the analysis to select 8 heavy rain thoughts 2005 July - is data until of September. Actual amount of rainfall 6.0~195.0 mm one time the antecedent precipitation showed API5 case 0.0~507.0mm and were observed peak flows (Qpeak) each from the P-1 $0.026m^3/sec{\sim}9.265m^3/sec$, from the P-2 $0.010m^3/sec-2.747m^3/sec$ and from the P-3c $0.064m^3/sec-13.482m^3/sec$ to show. Also amendment AMC condition it will be cool and it uses and the AGNPS model conference the result which it occurs, analysis and regression analysis of actual flow for as 0.992 very the possibility of getting the result which is good there was a decisive coefficient which is cool. But the gun is (T-P) with the total nitrogen (T-N) decisive coefficient each as 0.794 and 0.849 the presumption which is reliability generally will pay and with the fact that it will be the possibility of getting it is judged.

• Journal of Ecology and Environment
• /
• v.33 no.2
• /
• pp.165-173
• /
• 2010

Soil respiration ($R_S$) is a critical component of the annual carbon balance of forests, but few studies thus far have attempted to evaluate empirical regression models in $R_S$. The principal objectives of this study were to evaluate the relationship between $R_S$ rates and soil temperature (ST) and soil water content (SWC) in soil from a cool-temperate deciduous broad-leaved forest, and to evaluate empirical regression models for the prediction of $R_S$ using ST and SWC. We have been measuring $R_S$, using an open-flow gas-exchange system with an infrared gas analyzer during the snowfree season from 1999 to 2001 at the Takayama Forest, Japan. To evaluate the empirical regression models used for the prediction of $R_S$, we compared a simple exponential regression (flux = $ae^{bt}$Eq. [1]) and two polynomial multiple-regression models (flux = $ae^{bt}{\times}({\theta}{\nu}-c){\times}(d-{\theta}{\nu})^f:$ Eq. [2] and flux = $ae^{bt}{\times}(1-(1-({\theta}{\nu}/c))^2)$: Eq. [3]) that included two variables (ST: t and SWC: ${\theta}{\nu}$) and that utilized hourly data for $R_S$. In general, daily mean $R_S$ rates were positively well-correlated with ST, but no significant correlations were observed with any significant frequency between the ST and $R_S$ rates on periods of a day based on the hourly $R_S$ data. Eq. (2) has many more site-specific parameters than Eq. (3) and resulted in some significant underestimation. The empirical regression, Eq. (3) was best explained by temporal variations, as it provided a more unbiased fit to the data compared to Eq. (2). The Eq. (3) (ST $\times$ SWC function) also increased the predictive ability as compared to Eq. (1) (only ST exponential function), increasing the $R^2$ from 0.71 to 0.78.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.28 no.1
• /
• pp.76-80
• /
• 1983

In order to investigate the effect of boron and phosphorus for reduction of cold injury of rice, this experiment was undertaken by pot trial. Two levels of phosphorus and 6 levels of boron were applied once at the three stages such as tillering, panicle formation and meiosis stage. Cold water was irrigated to maintain cool temperature ranging 15 to $18^{\circ}C$ from panicle formation stage. It was shown a tendency that three to seven days of early heading were resulted by the 3, 5 and 10kg of boron application per 10 are. The ripening ratio and physiological root activity was rather slightly increased in the above boron levels.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.11a
• /
• pp.230-233
• /
• 2006

Small hydropower, one of renewable energies, is the clean energy which emits no carbonic acid gas. It has noting to do with global warming. It is a useful resource to contribute to the dispersion of power. Because of ballooning oil prices, the need for small hydropower is increasing. Recently small hydropower development using dams, small rivers, reservoirs, water pipes, sewage treatment plants and cool ing water of thermal power plants is conducting. By suggesting the strategy of the enlargement revitalization of small hydropower development, we hope to waken the people's interest in the small hydropower

• Proceedings of the Korea Concrete Institute Conference
• /
• 1999.04a
• /
• pp.299-304
• /
• 1999

Cracking of concrete is one of the main issues of structural design next to ensuring the load-bearing capacity. Thermal cracking is a recurring concern in the production of concrete structures in particular when large, massive structures are considered. Thremal stresses arise from the differential temperature distribution either within s sturcture or between newly cast sectons and adjoining older parts. There are many different methods of reducing thermal stresses. A method often used for reducing temperature within a structure, is to cool the inner core with embedded cooling pipes. In this study, finite element method is employed for thermal analysis of concrete structures. To calculate water temperature variation in pipe, the conservation of thermal energy in internal flow was adopted. The cooling effect of pipe cooling is studied with several factors like convective coefficient, water temperature, concrete heat characteristics

• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.05a
• /
• pp.437-442
• /
• 1998

Film boiling is the heat transfer mechanism that can occurs when large temperature differences exist between a cold liquid and hot material. In the nuclear reactor safety analysis, film boiling has become an important issue in recent years. During severe accident, hot molten corium fall into relatively cool water, and fragment into spheres or sphere-like particles. If the steam explosion is triggered, the thermal energy of corium is converted into the mechanical energy that can threaten the integrity of reactor vessel or reactor cavity. One of the important concerns in the heat transfer analysis during pre-mixing stage is the film boiling heat transfer between the corium and water/steam two-phase flow. Until now, considerable works on film boiling heat been performed. However, there is no available correlation adequate for severe accident analysis. In this study, boiling heat transfer correlations have been developed, and their applicable ranges heat been enlarged and their prediction accuracy has been enhanced.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.4
• /
• pp.570-575
• /
• 2010

This study is regarding development of an index table for antomation of welding process in impeller fabrication. A PLC, which is widely used for automation in industry, was also adopted as a controller for the index table because of it effectiveness, easy maintenance and repair. The index table consists of centering jig, blade jig, workbench, driving system and a controller. A touch screen was also prepaired as a man-machine interface to provide convenience for workers. Water jacket was installed inside the workbench to reduce thermal stress come from the welding. Temperature of the water jacket was kept constant to cool an impeller main plate effectively. The index table developed in this study convinces that it reduces the total welding time by 50% compared with the conventional process without the table.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.14 no.3
• /
• pp.171-180
• /
• 2009

Based on the constituent analysis of sediments near Dok Island, the origin and sedimentary facies were Investigated. The sediments are mainly from originated from volcanic and volcaniclastic rock fragments derived from Dok Island and carbonate sediments formed by a variety of shallow-dwelling organisms that secreted calcareous skeletons. Carbonate producers include mollusks (bivalves and gastropods), encrusting & branching bryozoans, encrusting & segmented red algae, worm tubes, barnacles, diatoms, sponge spicules and echinoderm fragments. The distribution and relative amount of these constituents are basically dependent upon water depth and grain size even though local variations can be observed within the same depth interval. Five sedimentary facies can be divided: nearshore facies (<20 m), neritic facies ($20{\sim}100m$), upper transitional facies ($100{\sim}200m$), lower transitional facies ($200{\sim}700m$), and hemipelagic facies (>700 m). The sediments that were sampled below the water depth of 2,000 m still contain a significant amount of carbonates (ca. $10{\sim}20%$), implying that the carbonate compensation depth in the East Sea may well exceed this water depth.

• Journal of Power System Engineering
• /
• v.19 no.4
• /
• pp.50-55
• /
• 2015

Recently, because of the deterioration of the nuclear generating station and increase of the cooler and heater, energy problem is increasing. To save the energy, the free cooling system is developed. The free cooling system is that cool the water to use cooled air in winter and is used in industrial process or data center. Yoon check the energy of free cooling system with dry cooler in korea. In this study, the value of the free cooling system with dry cooler is confirmed through using the NPV that is economic evaluation. when temperature degree of the cooled water is 10, in Chuncheon and Seoul the value is the most high. When temperature degree of the cooled water is 20, in Ulsan the value is the most high. As the result, because the using the temperature degree of the cooled water is high in the industrial process, the free cooling system is advantageous in korea.

• Geomechanics and Engineering
• /
• v.17 no.5
• /
• pp.475-483
• /
• 2019

Vegetation cover plays a vital role in stabilizing the soil structure, thereby contributing to surface erosion control. Surface vegetation acts as a shelterbelt that controls the flow velocity and reduces the kinetic energy of the water near the soil surface, whereas vegetation roots reinforce the soil via the formation of root-particle interactions that reduce particle detachment. In this study, two vegetation-testing trials were conducted. The first trial was held on cool-season turfgrasses seeded in a biopolymer-treated site soil in an open greenhouse. At the end of the test, the most suitable grass type was suggested for the second vegetation test, which was conducted in an environmental control chamber. In the second test, biopolymers, namely, starch and xanthan gum hydrogels (pure starch, pure xanthan gum, and xanthan gum-starch mixtures), were tested as soil conditioners for improving the water-holding capacity and vegetation growth in sandy soils. The results support the possibility that biopolymer treatments may enhance the survival rate of vegetation under severe drought environments, which could be applicable for soil stabilization in arid and semiarid regions.