• 한국농공학회논문집
• /
• 제48권2호
• /
• pp.45-55
• /
• 2006

This study analyze the hydrologic conditions and the effects of selected runoff characteristics as an attempt to estimate the optimal dredge amount for Asan Lake in Korea. The runoff feature was calculated by utilizing the water balance simulation from DIROM (Daily Irrigation Reservoir Operation Model), which allowed changes in landuse to be quantified using remote sensing for 14 years. The distribution of prospective sediment deposits was been tallied based on the changes in landuse, and quantity of incoming sediment estimated. From these findings, we were then able to simulate the fluctuation of water level, gauging the pumping days not already in use, to determine the frequency of the distribution for around the. requirement annual water storage and the changing water level. The optimal dredge amount was calculated on the basis of the distribution of frequency, taking into account the design criteria for agricultural water with the 10-year frequency of resistant capacity.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
• /
• pp.206-209
• /
• 2001

This study presents the leaching characterization of heavy metals according to changes of pH by ANC test on slag produced in electric arc furnace, bottom ash produced in coal-fired plants and their recycling products. Availability test was performed to assess the fraction of the total concentration that under worst environmental conditions could become available for leaching. TCLP, KLT(Korea Leaching Test) and KLTS(Korea Leaching Test of Soil contamination) were carried out to compare the leaching capacity and to estimate the adequacy of regulatory leaching test. Results from regulatory leaching tests could be misleading because the variable ANC of wastes can lead to very different final leachate pHs. The final pH of the regulatory test is not the ambient pH in the disposal environment, the actual solubilities of contaminants in the field may be entirely different from those predicted by these regulatory tests. Leaching behaviour of by-products was changed by recycling processes, therefore acid neutralization capacity and availability of new products, not leaching concentration by one batch regulatory test, are necessary to determine the method of recycling.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2011년도 전기공동학술대회 논문집
• /
• pp.7-10
• /
• 2011

According to the requirement of Res.MSC.285(86) for natural gas-fueled engine installations in ships, pump and compressor rooms should be fitted with effective mechanical ventilation system of the under pressure type, providing a ventilation capacity of at least 30 air changes per hour. It generally considered that gas leakage is more likely from a Fueled Gas Supply System(FGS) room as compared to other places, where installed in many kind of machinery or equipments like gas supply high-pressure pipes, valves, flanges and etc. Furthermore, leaked gas may be dispersed in a short time in an enclosed space, especially a FGS room, due to high pressure. However, the present requirement in Res.MSC.285(86) just considers the ventilating capacity of air changes per hour but the capacity of leaked gas. Hence, the current requirements may not meet effectively when enforcing the new propulsion systems as marine fuel. This study is conducted for the purpose of safety evaluation about the dispersion and ventilation efficiency with estimated leakage scenario. Numerical analysis predictions as the result of this paper are explained to know the features of flow pattern and the diffusion of natural gas concentration.

• 한국식품영양과학회지
• /
• 제26권6호
• /
• pp.1013-1020
• /
• 1997

To elicit the effect of fermentation on food quality of the watery Chinese cabbage pickles without fish sauce and red pepper paste(Baik-kimchi), changes in physicochemical properties and microstructure of fiber components were studied. Better water holding capacity(WHC) was showed in Baik-kimchi fermented at $25^{\circ}C$ than that of Baik-kimchi fermented at 5$^{\circ}C$. WHC measured at pH 2 and 6 were ranged from 10.18 to 16.79g/g dried sample for Baik-kimchi fermented at $25^{\circ}C$ and 6.51~14.58g/g dried sample for sample for samples at 5$^{\circ}C$, respectively. The higher WHC was resulted in pH controlled freeze-dried sample to pH 6 than that measured in pH 2 sample. The settling volume(SV) and oil adsorption capacity(OAC) increased with fermentation period and kept the same value for a little while, but slightly decreased in the over ripening period. Baik-kimchi fermented at $25^{\circ}C$ exhibited more shrunk microstructure of parenchyma cell and xylem than those of Baik-kimchi fermented at 5$^{\circ}C$. The appearance of SDF of the both Baik-kimchi ripened at 5$^{\circ}C$ and $25^{\circ}C$ could give granular shape, whereas the overripened Baik-kimchi had smooth surface of SDF. On the other hand, the IDF retained the original shape during fermentation.

• 한국분말재료학회지
• /
• 제25권6호
• /
• pp.507-513
• /
• 2018

This study investigates the viability of using a Na-ion battery with a tin(Sn) anode to mitigate the vulnerability caused by volume changes during discharge and charge cycling. In general, the volume changes of carbon material do not cause any instability during intercalation into its layer structure. Sn has a high theoretical capacity of $847mAh\;g^{-1}$. However, it expands dramatically in the discharge process by alloying Na-Sn, placing the electrode under massive internal stress, and particularly straining the binder over the elastic limit. The repeating strain results in loss of active material and its electric contact, as well as capacity decrease. This paper expands the scope of fabrication of Na-ion batteries with Sn by fabricating the binder as an auxetic structure with a unique feature: a negative Poisson ratio (NPR), which increases the resistance to internal stress in the Na-Sn alloying/de-alloying processes. Electrochemical tests and micrograph images of auxetic and common binders are used to compare dimensional and structural differences. Results show that the capacity of an auxetic-structured Sn electrode is much larger than that of a Sn electrode with a common-structured binder. Furthermore, using an auxetic structured Sn electrode, stability in discharge and charge cycling is obtained.

• 산업기술연구
• /
• 제21권B호
• /
• pp.195-203
• /
• 2001

The purpose of this study is to estimate ultimate uplift capacity of permanent anchor which was cast into weathered rock. The ultimate uplift capacity was estimated from the load-displacement curve of four different anchors which have different bond length. The creep test was performed for 15minutes under the maximum load of each step in order to understand the load-transfer property of permanent anchor and to decide which anchor to choose. The destruction range of soil due to the changes in load was estimated by installing dial gauge on the ground which was cast into the weathered rock. Ultimately, the study on the behavior of the anchor case into the weathered rock was performed by comparing and analyzing the estimated result of the UUC obtained by the full scale pull out test in the field with the exsting theoretical and practical results of soil and rock anchor.

• 콘크리트학회논문집
• /
• 제11권3호
• /
• pp.153-160
• /
• 1999

Water soluble hydroxyalkyl methycellulose ethers are used in a variety of applications incluing building industry as a supplementary agent used for incresing adhesives, water retention capacity, workability and viscosity modify. Water retention capacity(WRC) is the capability to contain water in the ploymer chain under condition of being mixed with cement. In general, the WRC is affected by the viscosity, the adding amount, the particle size, the rate of dissolving and the amount of substituted chemical in cellulose ethers. In the other words, WRC is increased as higher the viscosity, more adding amount, finer the particle size and longer the dissolving time of cellulose ethers. This thesis investigated each factor that effect the WRC, particularly the relation between degree of substitution(DS), molar of substitution(MS) and WRC. It is observed that WRC is not nearly affected by DS of cellulose ethers, but is changes proportionally as MS increases in the narrow range(0.10~2.25)

• Journal of Electrical Engineering and Technology
• /
• 제13권4호
• /
• pp.1483-1493
• /
• 2018

Recently, more power facilities are needed to cope with the increasing electric demand. However, the additional construction of generators, transmission and distribution installations is not easy because of environmental problems and citizen's complaints. Under this circumstance, a microgrid system with distributed renewable resources emerges as an alternative of the traditional power systems. Moreover, the configuration of power system changes with more DC loads and more DC installations. This paper is written to introduce an idea of a genetic algorithm-based solution to determine the optimal capacity of the distributed generators depending on the types of system configuration: AC-link, DC-link and Hybrid-link types. In this paper, photovoltaic, wind turbine, energy storage system and diesel generator are considered as distributed generators and the feasibility of the proposed algorithm is verified by comparing the calculated capacity of each distributed resource with HOMER simulation results for 3 types of system configuration.

• The Korean Journal of Physiology and Pharmacology
• /
• 제5권5호
• /
• pp.397-405
• /
• 2001

The ryanodine receptor, a $Ca^{2+}$ release channel of the sarcoplasmic reticulum (SR), is responsible for the rapid release of $Ca^{2+}$ that activates cardiac muscle contraction. In the excitation-contraction coupling cascade, activation of SR $Ca^{2+}$ release channel is initiated by the activity of sarcolemmal $Ca^{2+}$ channels, the dihydropyridine receptors. Previous study showed that the relaxation defect of diabetic heart was due to the changes of the expressional levels of SR $Ca^{2+}$ATPase and phospholamban. In the diabetic heart contractile abnormalities were also observed, and one of the mechanisms for these changes could include alterations in the expression and/or activity levels of various $Ca^{2+}$ regulatory proteins involving cardiac contraction. In the present study, underlying mechanisms for the functional derangement of the diabetic cardiomyopathy were investigated with respect to ryanodine receptor, and dihydropyridine receptor at the transcriptional and translational levels. Quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of those changes in diabetic heart were investigated. The levels of protein and mRNA of the ryanodine receptor in diabetic rats were comparable to these of the control. However, the binding capacity of ryanodine was significantly decreased in diabetic rat hearts. Furthermore, the reduction in the binding capacity of ryanodine receptor was completely restored by insulin. This result suggests that there were no transcriptional and translational changes but functional changes, such as conformational changes of the $Ca^{2+}$ release channel, which might be regulated by insulin. The protein level of the dihydropyridine receptor and the binding capacity of nitrendipine in the sarcolemmal membranes of diabetic rats were not different as compared to these of the control. In conclusion, in diabetic hearts, $Ca^{2+}$ release processes are impaired, which are likely to lead to functional derangement of contraction of heart. This dysregulation of intracellular $Ca^{2+}$ concentration could explain for clinical findings of diabetic cardiomyopathy and provide the scientific basis for more effective treatments of diabetic patients. In view of these results, insulin may be involved in the control of intracellular $Ca^{2+}$ in the cardiomyocyte via unknown mechanism, which needs further study.

• 산업경영시스템학회지
• /
• 제20권44호
• /
• pp.81-92
• /
• 1997

The purpose of this paper is to develop a method of paramatric analysis that can be applied to an optimal solution of a maximum flow problem. We first define the transformed network corresponding to a given network. In such a network, we conduct paramatric analysis by determining changes in the optimal solution precipitated by changes in the capacity as the arc capacity varies from 0 to infinite. By this method we can easily calculate not only the characteristic region where the given optimal solution remains unchanged, but also the characteristic region where the value of the maximal flow gradually increases or decreases. The proposed method is demonstrated by numerical example.