• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.252-255
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• 2005

The operation of a gas-turbine engine gradually deteriorates the performance of its main components and often generates the defects of its components. The GPA method has been usually used for the diagnosis of the deterioration. In this study, the diagnostic code of the engine performance using the thermodynamic sensitivity between the sensed parameters and the health parameters has been developed without an application of the commercial program. The single performance deterioration of the turbo-shaft engine for SUAV has been estimated with this code.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.289-292
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• 2005

Because of accumulation of operation time, the performance of main components(compressor, combustor, turbine, etc.) come to be deteriorated in gas-turbine engine. So, high reliability and minimun of expense are important problem for engine manufacturer and user in operation of gas-turbine engine. In this study, the diagnostic code of the engine performance using the thermodynamic sensitivity between the sensed parameters and the health parameters has been developed without an application of the commercial program. The single performance deterioration of the turbo-shaft engine has been estimated with this code.

• Atmosphere
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• v.24 no.4
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• pp.555-563
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• 2014

The impacts of dynamic and thermodynamic schemes used in the Community Ice CodE (CICE), the Los Alamos sea ice model, on sea ice concentration, extent and thickness over the Arctic and Antarctic regions are evaluated. Using the six dynamic and thermodynamic schemes such as sea ice strength scheme, conductivity scheme, albedo type, advection scheme, shortwave radiation method, and sea ice thickness distribution approximation, the sensitivity experiments are conducted. It is compared with a control experiment, which is based on the fixed atmospheric and oceanic forcing. For sea ice concentration and extent, it is found that there are remarkable differences between each sensitivity experiment and the control run over the Arctic and Antarctic especially in summer. In contrast, there are little seasonal variations between the experiments for sea ice thickness. In summer, the change of the albedo type has the biggest influence on the Arctic sea ice concentration, and the Antarctic sea ice concentration has a greater sensitivity to not only the albedo type but also advection scheme. The Arctic sea ice thickness is significantly affected by the albedo type and shortwave radiation method, while the Antarctic sea ice thickness is more sensitive to sea ice strength scheme and advection scheme.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2281-2285
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• 2013

The electronic structure, optical spectra, and thermodynamic properties of the three FOX-7 polymorphs (${\alpha}$, ${\beta}$, and ${\gamma}$) have been studied systematically using density functional theory. The LDA (CA-PZ) and generalized gradient approximation (GGA) (PW91) functions were used to relax the three FOX-7 phases without any constraint. Their density of states and partial density of states were calculated and analyzed. The band gaps for the three phases were calculated and the sequence of their sensitivity was presented. Their absorption coefficients were computed and compared. The thermodynamic functions including enthalpy (H), entropy (S), free energy (G), and heat capacity ($C_p$) for the three phases were evaluated.

• 한국지구과학회:학술대회논문집
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• 2002.02a
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• pp.41-41
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• 2002

• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.26-31
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• 1996

Since biosynthesis of lignin peroxidase from Phanerochaete chrysosporium was known to be sensitive to shear, it is interesting to understand the effects of the shear sensitivity for the overproduction of lignin peroxidase. In stirred-tank fermentor, the shear-sensitivity in lignin peroxidase biosynthesis was quantified by using Kolmogorov length scale. It was found that agitation at 80$\mu$m Kolmogorov length scale is advantageous for the production of lignin peroxidase from P. chrysosporium. To overcome the shear sensitivity in lignin peroxidase biosynthesis caused by the agitation,P. chrysosporium was immobilized on various solid carriers. The nylon-immobilized P. chrysosporium was chosen in the present study as a way to overcome the shear sensitivity at the ranges of above 50$\mu$m Kolmogorov length scale. The adhesion force between immobilized cell and carrier can be predicted by thermodynamic approach and used as a criteria to select an adequate carrier materials for immobilization.

• Advances in nano research
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• v.10 no.2
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• pp.175-189
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• 2021

In this article, frequency characteristics, and sensitivity analysis of a size-dependent laminated composite cylindrical nanoshell under bi-directional thermal loading using Nonlocal Strain-stress Gradient Theory (NSGT) are presented. The governing equations of the laminated composite cylindrical nanoshell in thermal environment are developed using Hamilton's principle. The thermodynamic equations of the laminated cylindrical nanoshell are obtained using First-order Shear Deformation Theory (FSDT) and Fourier-expansion based Generalized Differential Quadrature element Method (FGDQM) is implemented to solve these equations and obtain natural frequency and critical temperature of the presented model. The novelty of the current study is to consider the effects of bi-directional temperature loading and sensitivity parameter on the critical temperature and frequency characteristics of the laminated composite nanostructure. Apart from semi-numerical solution, a finite element model was presented using the finite element package to simulate the response of the laminated cylindrical shell. The results created from finite element simulation illustrates a close agreement with the semi-numerical method results. Finally, the influences of temperature difference, ply angle, length scale and nonlocal parameters on the critical temperature, sensitivity, and frequency of the laminated composite nanostructure are investigated, in details.

• Nuclear Engineering and Technology
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• v.36 no.2
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• pp.196-202
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• 2004

KAERI (Korea Atomic Energy Research Institute) is at present preparing a preliminary performance assessment to set up the HLW disposal concept of Korea. The solubility of the radionuclides contained in HLW is necessary as a source term in order to predict their potential migration in both the near and far fields. The solubility of actinides (Th, Am, U, Np and Pu) for a reference deep groundwater of Korea has been calculated using a geochemical code with thermodynamic data selected by a peer review of existing thermodynamic databases and literature. The solubilities from the experimental study and/or field observations from natural analogue studies are compared. The sensitivity of solubility to the variability of three main parameters of groundwater (pH, Eh, and carbonate concentration) is also investigated. The results of the sensitivity analysis show that the solubility of actinides strongly depends on the parameters considered. Within the range of parameter values studied (pH=7 to 10, Eh=-0.4 to -0.1V, and carbonate concentration=1.E-5 to 1.E-2 mol/L), the solubility of each actinide exists between 1.4E-10 and 1.6E-6 mol/L for Am, 4.9E-9 and 2.8E-6 mol/L for Th, 3.2E-9 and 5.7E-4 mol/L for U, 1.1E-9 and 1.0E-7 mol/L for Np, and 4.0E-11 and 2.8E-6 mol/L for Pu, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.76-83
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• 2003

Exergetic and thermoeconomic analyses were performed fer a 137-MW steam power plant. In these analyses, mass and energy conservation laws were applied to each component of the system. Quantitative balance of the exergy and exergetic cost for each component, and for the whole system was carefully considered. The exergo-economic model, which represented the productive structure of the system was used to visualize the cost formation process and the productive interaction between components. The computer program developed in this study can determine production costs of power plants, such as gas-and steam-turbines plants and gas-turbine cogeneration plants. The program can also be used to study plant characteristics, namely, thermodynamic performance and sensitivity to changes in process and/or component design variables.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.264-267
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• 2010

This research focuses on the development of numerical code to deal with compressible two phase flow around three dimensional objects combined with cavitation model suggested by Weishyy et al. with k-e turbulent model. The cryogenic cavitation is carried out by considering the thermodynamic effect on physical properties of cryogenic fluids in physical point of view and implementing the temperature sensitivity in the energy equation of the government equations in numerical point of view, respectively. The formulation has been extensively validated for both liquid nitrogen and liquid hydrogen by simulating the experiments of Hord on hydrofoils. Then, simulations of cavitating turbopump inducers at their design flow rate are presented. Results over a broad range of Nss numbers extending from single-phase flow conditions through the critical head break down point are discussed. In particular, thermal depression effects arising from cavitation in cryogenic fluids are identified and their impact on the suction performance of the inducer quantified.