• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.61-64
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• 2005

The calculated characteristics of groundwater within the Youngsan river basin are : casing depth-17.1m, well depth-74.8m, natural water-2.6m, pumping water-43.9m, yields-391$m^3/D$, transmissivity-16.3$m^3/D/m$, storativity-0.068. As far as hydrogeological units are concerned, in casing depth, weathered granites are deepest followed by gneiss, volcanics, and sediments. In major aquifer development areas, sediments are deepest followed by volcanics, granites and gneiss in more shallow areas, Altogether, the major aquifar development depth of the Youngsan river basin is within the $35{\sim}60m$ range.

• Journal of the Korean Geophysical Society
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• v.7 no.1
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• pp.41-41
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• 2004

56 samples were analyzed to understand water quality of the natural mineral water of Korea. The geology according to each sample location is grouped into Precambrian metamorphic rocks, Okcheon metamorphic rocks, Jurassic granite, Cretaceous granite, and Jeju volcanic rocks. Average EC and pH values of the water is 150 μS/cm and 7.3, respectively and water type of the water is mainly Ca-Na-HCO3. Fundamentally, there still is no problem for the water quality of the natural mineral water. Nevertheless, nitrate was detected and arsenic and fluoride contents are near the drinking water standards, it is highly necessary to manage the water quality by installment of casing and grouting or by development of another production well.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3050-3055
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• 2007

A wind turbine is one of the most popular energy conversion systems to generate electricity from the natural renewable energy source and an axial-flow type wind turbine is the most popular system for the electricity generation in the wind farm nowadays. In this study, a cross-flow type turbine has been studied for the application of wind turbine for electricity generation. The target capacity of electric power generation of the model wind turbine developing on the project is 12 volts, 130A/H (about 1.56kW). The important design parameters of the model turbine impeller are the inlet and exit angle of the turbine blade, number of blade, hub/tip ratio and the exit flow angle of the casing. In this study, the radial equilibrium theorem was used to decide the inlet and exit angle of the impller blade and CFD technique was used to have the performance analysis of the designed model power turbine to find out the optimum geometry of the CPT impeller and casing. The designed CPT with 24 impeller blades at ${\alpha}=82^{\circ}$, ${\beta}=40^{\circ}$ of turbine blade angle was estimated to generate 284.6 N.m of indicated torque and 2.14kW of indicated power.

• Journal of Soil and Groundwater Environment
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• v.24 no.1
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• pp.35-42
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• 2019

In installation of groundwater wells, grouting materials are injected between the groundwater borehole and the inner casing in order to prevent infiltration of contaminated groundwater from the top soil layers into wells. The injection device of grouting materials is commonly composed of an inlet head device with an expansion packer, a cylinder capable of storing the grouting materials, and an air cylinder. In this work, two types of common grouting materials, silicon and cement materials, were tested for their performances as grouting media. For silicon. silicon was mixed with clay or calcite, and tested for their tensile strength and underwater reactivity. Both silicon-clay and silicon-calcite mixtures had adequate flow and adhesiveness. For cement material, general cement, ultra-rapid harding cement, and natural cement were respectively mixed with three different soil types including coarse-grained granite, fine-grained granite, and gneiss, and direct shearing tests were conducted after hardening. Under grouting depth condition of 30 m, the minimum adhesive strength was greater for weathered gneiss than non-weathered gneiss with its maximum values obtained from the mixtures of ultra rapid-harding cement.

• Food Science of Animal Resources
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• v.24 no.1
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• pp.50-56
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• 2004

The wienner sausage(natural casing, N), wienner sausage(collagen casing, C), frankfurter sausage(F) and can products[spam(S), luncheon meat(L), jangjorim(J)] were obtained from different Korean meat processing companies and investigated for their salinity, saccharinity, pH, moisture and fat content, meat color and sensory evaluation. In sausage products, the saccharinity percent ranged 4.9∼5.0 in N, 6.6∼8.0 in C, and 5.2∼6.5 in F. The salinity percent of C and F were slightly higher than that of N. The pH values of all sausage product were above 6.0. The L＊ values of N were ranged 49.8∼56.7, which were slightly lower than those of C and R The sausage with high content of crude fat and high L＊value earned the highest score in overall acceptability. In can products, saccharinity percentage was higher in J compared to the S and L. The salinity percentage of S was slightly higher than those of Land J. In meat color, L＊ and a＊ values were not different between S and L, although b＊ value of L was slightly higher than that of S and J. There were not significantly different among can products, however, the product containing low-salt had the highest score in overall acceptability.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.1
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• pp.74-80
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• 2012

The vibration of a LP turbine case may cause the failure of power generation and reduce the life of its facility. In this study we carried out on-site measurements of a LP turbine in order to find the cause of the vibration and conducted experimental and numerical modal analysis of the turbine case with its support frame. The measurement and the modal analysis show that the natural frequency of the turbine becomes close to 60 Hz due to the subsidence of the support. The elimination of the subsidence by shimming between the turbine and the support frame gave rise to the reduction of the vibration of the LP turbine case.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.191-197
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• 1998

The recent results of the engine development performed in this you on Turbogreen 1200, the first industrial gas turbine engine developed in Korea, are presented. In order to improve the engine performance and structural stability from the first prototype engine, several variants of the engine and major components such as combustor and rotor assembly have been developed and tested. This paper shows these results especially focused on the engine test and performance analysis, in which test system, instrumentation and data processing are discussed as well. The engine performance and its trend give relatively good coincidence with the design ones. At design power of 1.2MW, the thermal efficiency of the engine is estimated over $25\%$ which is below the design target of $27.2\%$. This gap of efficiency is caused mainly by large tip clearance between turbine blades and casing. Considering high design efficiency superior to those of other competitive engines in this power class, Turbogreen 1200 would have a strong competition in its performance if the design efficiency is achieved by further developments such as tip clearance control, which are very possible and natural in final mass production of the developed gas turbine engine.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.845-851
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• 2006

Spent compost wheat straw is an available by-product from edible mushroom production, which constitutes a potential pollutant and is cost effective for disposal. This study was conducted to determine the nutritive value as ruminant feed of spent wheat straw compost from Agaricus bisporus mushroom production. The compost was provided from a mushroom farm, the casing soil was removed from the whole compost, and then it was sun dried and sampled for chemical analysis. An experiment was conducted, in which four wheat straw-based diets comprising control (I), 10% spent straw (II), 20% spent straw (III) and 30% spent straw (IV) were tested in a cross-over design using 8 sheep. Dry matter intake (DMI) was 74.0, 73.8, 70.2 and 57.1 and organic matter intake (OMI) was 62.7, 63.4, 58.0 and 44.4 g per kg $BW^{0.75}$ for diets I, II, III and IV, respectively, which, were significantly (p<0.05) lower for diet IV. Digestible OMI was respectively 33.1, 32.6, 30.6 and, 20.2 g per kg $BW^{0.75}$ on the four diets which were significantly (p<0.05) different between the treatments. Inclusion of spent compost straw up to 20% of the diet did not affect the digestibility of DM, OM, CF, ADF and NDF, but the diet containing 30% compost straw had statistically (p<0.05) lower digestibilities. Nitrogen balance was also significantly (p<0.05) different between the treatments.

• Journal of Korean Society on Water Environment
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• v.32 no.5
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• pp.442-449
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• 2016

The goal of this study is to provide basic data to establish a foundation for the provision of safe drinkable water. The raw water of natural mineral water was analyzed to determine the quantities of anions (F^-, Cl^-, NO_3-N^-, and SO₄^2- ) and cations (Ca²⁺, K⁺, Mg²⁺, and Na⁺) during the former and latter half of 2016. Analysis of the current quality of the raw water of natural mineral water among domestic manufacturers showed average anions contents of 0.46mg/L of fluorine, 8mg/L of chlorine ion, 1.5mg/L of nitrate nitrogen, and 12mg/L of sulfate ion. While the fluorine content was greater than the water quality criterion of 2.0mg/L at four points, the fluorine level was overall stable. The average cations contents included 21.3mg/L of calcium, 1.0mg/L of potassium, 3.4mg/L of magnesium, and 9.6mg/L of sodium. The chemical characteristics were compared among the major ions, and the results are presented in a piper diagram. The content ratio of cations was in the order of Ca²⁺> Na⁺>Mg²⁺>K⁺, whereas that of anions was in the order of SO₄^2->Cl^->NO_3-N^->F^-. While the cations were slightly scattered, the anions were generally concentrated except for at a few points. The Ca-Na-HCO₃ type was dominant overall in water sources from diorite, gneiss, and granite, while the Na-Mg-Ca-HCO₃-Cl type was dominant in basalt sources. Mineral water manufacturers source their water under various conditions, including in-hole casing, excavation depth, and contact state of bedrock; even within the same rocky area, some differences in the water quality type can occur. When the depth of the water source was taken into account, the mean anions contents of F^-, Cl^-, NO_3-N^-, and SO₄^2- were similar, with no significant differences according to depth. Of the cations, K⁺ and Na⁺ showed no significant differences across all the tubular wells, whereas Ca²⁺ and Mg²⁺ decreased in content with depth.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.937-942
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• 2008

This paper presents a case history on failures of impeller and shaft due to pressure pulsation at single stage feed water pumps in 700 MW nuclear power plant during commissioning operation. The pumps had been service and had run for approximately $40{\sim}50$ hours. For the most part, the failures of impeller occurred with the presence of a number of fatigue cracks. All cracks were associated with the deleterious surface layer of impeller by visual and metallurgical examination. On-site testing and analytical approach was performed on the systems to diagnose the problem and develop a solution to reduce the effect of exciting sources. A major concern at high-energy centrifugal pump is the pressure pulsation created from trailing edge of the Impeller blade, flow separation and recirculation at centrifugal pumps of partial load. Pressure pulsation due to the interaction generating between impeller and casing coincided with natural frequencies of the impeller and shaft system during 1ow load operation. It was identified that dynamic stress exceeding the fatigue strength of the material at the thin shroud section due to the hydraulic instability at running condition below BEP.