• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.1
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• pp.177-188
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• 1987

A compute program based on the minimization of total Gibbs' free energy and enthalpy balance was developed to calculate the chemical equilibrium composition and adiabatic flame temperature, especially stressed on NO and CO concentration of Heavy oil. Twenty four components of combustion gases which would be produced from the combustion of Heavy oil were chosen and utilized for the products composition analysis of competing combustion reaction. As the results, following conclusions were turned out; (1) Maximum adiabatic flame temperature was found around to be 2900K, when the stoichiometric air ratio was 0.8. (2) Maximum NO quantity in adiabatic process was occurred when supplied air quantity was around 120% of theoretical air requirement. (3) NO and CO quantities were increased with combustion gas temperature at constant stoichiometric air ratio. (4) At constant temperature of combustion gas, NO quantity was increased and Co quantity was decreased with supplied air quantity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.2
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• pp.61-66
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• 2014

Exhaust heat recovery ventilation systems conserve energy through enthalpy recovery between air intake and exhaust, and they are being increasingly used. An exhaust heat recovery ventilation system can be installed in the ceiling of a balcony or emergency evacuation space. However, in the case of fire, the emergency evacuation space has to by law remain as empty space, and therefore, a ventilation system can't be installed in an emergency evacuation space. Therefore, the need for a proper installation space for a ventilation system is emphasized. In this study, to install a heat recovery ventilation system in a lightweight wall, a heat exchanger was assembled of thickness below 140 mm. The efficiency of heat recovery was analyzed through performance experiment, in the case of the cooling and heating mode. The heat recovery efficiency increases when the surface area is increased, by using closer channel spacing in the heat exchanger, or by increasing the size of the heat exchanger.

• Bulletin of the Korean Chemical Society
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• v.4 no.3
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• pp.115-119
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• 1983

The ionic association constants (K) of 2, N-dimethyl pyridinium iodide (2NDMPI) in 95 volume percentage ethanol-water mixture were determined by a modified UV and conductance method at $20^{\circ}C{\sim}50^{\circ}C$ under 1 to 2000 bars. The K values increase with increasing pressure and decrease with temperature. The total partial molar volume change (${\Delta}V$) has relatively small negative value and the absolute ${\Delta}V$ value decrease with increasing pressure and temperature. The ion size (a) and solvation number (n) of 2NDMPI were about 5 $\AA$ and changed from 1 to 3 with decreasing temperature. Other thermodynamic parameters such as enthalpy (${\Delta}H^{\circ}$) and entropy (${\Delta}S^{\circ}$) for the equilibrium of the 2NDMPI were evaluated. From all the parameters mentioned above, we came to conclusion that the electrostriction effect of 2NDMPI in the ethanol-water mixture is enhanced with increasing pressure and decreasing temperature.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.3
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• pp.110-122
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• 1996

Finite element analysis tool was developed to analyze the casting process. Generally, casting process consists of mold filling and solidification. Both filling and solidication process were simulated simultaneously to investigate the effects of process variables and to predict the defect. At filling process, thermal coupling was especially considered to investigate thermal history of material during the filling stage. And thermal condition at the final stage of filling is used as the initial conditions in a solidification process for the exact simullation of the actual casting processes. At mold filling process, Lagragian-type finite element method with automatic remeshing scheme was used to find the material flow. A perturbation method with artificial viscosity is adopted to avoid numerical instability in low viscous fluid. At solidification process, enthalpy-based finite element method was used to solove the heat transfer problem with phase change. And elastic stress analysis has been performed to predict the thermal residual stress. Through the FE analysis, solidification time, position of solidus line, liquidus line and thermal residual stress are found. Through the study, the importance of combined analysis has been emphasized. Finite element tools developed in this study will be used process design of casting process and may be basic structure for total CAE system of castings which will be constructed afterward.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.276-284
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• 2014

The purpose of this study is to establish the designing method of ORC(Organic Rankine Cycle) radial inflow turbines. RTDM(Radial Turbine Design Modeler) Ver.2.1 which is a preliminary design program of radial inflow turbines was developed to achieve this purpose. The 200kW-class radial inflow turbine for OTEC(Ocean Thermal Energy Conversion) was designed by using the RTDM Ver.2.1 and CFD(Computational Fluid Dynamics) simulation was performed to verify the accuracy of RTDM Ver.2.1. With the result of simulation, the accuracy of RTDM Ver.2.1 was almost 94.6% based on the designed total enthalpy drop of the radial inflow turbine. Strategy of adjusting the mass flow rate was adopted on this study to satisfy the requirements of its power and rotor outlet's conditions for the designed radial inflow turbine. The mass flow rate was consequently increased to 21.2 kg/s for the designed 200kW-class radial inflow turbine for OTEC, and then Total to total and Total to static efficiency are 89.8% and 85.36% respectively.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.600-605
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• 1999

Methyl linoleate was oxidized at 60, 90, 120 and $150^{\circ}C$, respectively, with sparging oxygen for different periods of time. On the basis of the peroxide values determined at four temperatures, four heating times were chosen for the analysis of physicochemical parameters, such as peroxide value, total oxidation products, polymer content, viscosity, refractive index and characteristics of thermal degradation by DSC (Differential Scanning Calorimeter). The content of peroxide linkage (C-O-O-C) polymer and ether or carbon to carbon linkage (C-O-C/C-C) polymer were analyzed by High Performance Size Exclusion Chromatography (HPSEC). The polymer formed at four temperatures was qualitatively identified as dimer. The polymer with peroxide linkage (C-O-O-C) were detected from methyl linoleate oxidized at $60^{\circ}C\;and\;90^{\circ}C$, but they were not detected from methyl linoleate oxidized at $120^{\circ}C\;and\;150^{\circ}C$. The enthalpy changes increased as peroxide value increased whereas maximum degradation temperature decreased. The highest correlation coefficients were obtained between maximum degradation temperature $(T_m)$, exothermic enthalpy changes and peroxide value, peroxide linkage (C-O-O-C) polymer content.

• Food Science and Preservation
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• v.12 no.2
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• pp.101-106
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• 2005

This study was carried rut to investigate the quality properties of two cocked germinated-brown rices(A- and B-product). Color value of A- and B-product were L=68.46, a=0.92, b=9.49 and L=69.32, a=-1.10, b=9.77, respectively. Moisture content of those was $64.5\%$. The free sugar contents of A-product were $0.2\%$ glucose, $0.15\%$ sucrose, $0.18\%$ maltose, and those of B-product were $0.14\%$ glurose, $0.50\%$ sucrose, $0.17\%$ maltose, respectively. Vitamin E content in A-product was $30.7\;{\mu}g\;100\;g$ and $46.9\;{\mu}g\;100\;g$ in B-product. Total dietary fiber contents were $2.8\%$, and $2.2\%$, respectively. The DSC(differential scanning calorimetry) characteristics of two cooked germinated-brown rices showed similar pattern. Onset temperature and gelatinization enthalpy of peak 1 were $56.5^{\circ}C$, 5.46 J/g in A-product and $56.2^{\circ}C$, 5.56 J/g in B-product, respectively. Onset temperature and melting enthalpy of peak 2 were $109.5^{\circ}C$, 0.33 J/g in A-product and $108.9^{\circ}C$, 0.37 J/g in B-product, respective1y. Sensory properties of cocked germinated-brown rices were affected by appearance, taste and texture. Palatability score of B-product was higher than that of A-product.

• CELLMED
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• v.4 no.2
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• pp.14.1-14.6
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• 2014

KH-BaRoKer-SeongJangTang (KBS) is a recently developed formulation by using traditional drugs considering traditional medical theory of Oriental books such as ShinNongBonChoGyeong and JuRye, which has been used to improve the growth of child in Korea. Although KBS is usually prescribed to many children who are in retard for their age, its pharmacological effects have not been fully understood in experimental models. The aim of this study was to evaluate the effects of KBS on bone growth. Growth plate thickness and bone parameters such as bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), connection density (Conn.D), and total porosity were analyzed by means of microcomputed tomography. Serum insulin-like growth factor-I (IGF-I) levels were measured by enzyme-linked immunosorbent assay. Hepatic IGF-I mRNA expression was analyzed by real-time polymerase chain reaction. Phosphorylation of signal transducer and activator of transcription5 (STAT5) was investigated using Western blot analysis and immunohistochemistry. The thickness of growth plate was increased by KBS. BV/TV, Tb.Th, TbN, Conn.D, and total porosity were improved by KBS. Hepatic IGF-I mRNA and serum IGF-I levels were elevated by KBS. Phosphorylation of STAT5 was increased with administration of KBS. These results suggest that KBS would be helpful to children who are in retard for their age through the elevation of IGF-I.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.5
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• pp.210-215
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• 2006

Mechanical alloying (MA) by high energy ball mill of pure copper and niobium powders was carried out under the Ar gas atmosphere. The supersaturated solid solution can be produced in the range up to $Cu_xNb_{100-x}$(x=5-30) by MA for 120 hrs, as demonstrated by X-ray diffraction, DSC analysis and the electronic studies through a change in the superconducting transition in the low-temperature specific heat. The $Cu_{30}Nb_{70}$ samples ball-milled for 120 hrs exhibit only a broad exothermic heat release. The total energy, ${\Delta}H_t$ accumulated during MA far the mixture of $Cu_{30}Nb_{70}$ powders increased with milling time and approached the saturation value of 7.5 kJ/mol after 120 h of milling. It can be seen that the free energy difference between the supersaturated solid solution and the mixture of $Cu_{30}Nb_{70}$ powders is estimated to be 7 kJ/mol by Miedema et al. Hence it is thermodynamically possible to assume the formation of a supersaturated solid solution phase in this system.

• Korean journal of food and cookery science
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• v.22 no.2 s.92
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• pp.193-203
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• 2006

The quality characteristics of cookies containing black rice flour, which has a greater variety of functional components than wheat flour, were studied. The results of the pasting properties shows that the inclusion of black rice flour to the wheat flour-mixture did not affect the pasting temperature but increased the enthalpy, indicating that more energy is needed for the starch gelatinization. The total dietary fiber and total polyphenol content increased and the cookies color became darker and deeper with increasing black rice flour content. According to the results from TA on texture, the hardness decreased and the crispness increased significantly (both, p<0.001) with increasing black rice flour content. From the acceptance test, the appearance, aroma and texture of the cookies with added black rice flour were significantly (p<0.001) lower than those of the wheat flour cookies. However, the taste and overall acceptance of the cookies with added black rice (lour did not differ significantly from those of the wheat flour cookies. According to the results from the sensory evaluation, the aroma, black rice flavor, crispness, graininess and color(gray-violet) of the cookies increased significantly(p<0.001) with increasing black rice flour content and those of the cookies with 30% black rice flour had the highest values among the cookies which weren't significantly different from those of the cookies with 20% black rice flour. From the above results, the optimal ratio for the addition of black rice flour to the cookies was 10% from the viewpoint of the sensory evaluation and functional components.