• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.121-123
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• 2008

The PV modules are affected by heat. The hotter the PV module, the lower the power output, then the life time will be short. If the cell temperature rises above a certain limit the encapsulating materials can be damaged, and this will degrade the performance of the PV module. This is called the ‘hot spot’ formation. This paper presents that the PV module temperature can be estimated by using a thermal analysis program, and demonstrates the thermal characteristics of the PV module.

• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.166-174
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• 2001

An apparatus for detecting remote real-time uranium concentration using an optrode was developed. An optrode to detect uranium fluorescence as remote real-time control was designed. Fluorescence intensity at time 2ero was derived by the fluorescence signal processing and the algorithm to exclude the quenching effect of various quenchers and temperature fluctuations. This apparatus employing the above deriving method and the optrode has an error range within 6% in spite of serious fluorescence lifetime changes due to the quenching effect and temperature fluctuations. The detection limit is 0.06 ppm and the linearity is excellent between 0.06 ppm and 2 ppm on the aqueous uranium solution.

• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.39-44
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• 2019

In this study, fire and evacuation safety of environmental energy facilities using fire and evacuation simulation was examined as part of performance-oriented design. The worst-case fire scenarios in which fire-fighting facilities such as sprinkler fire extinguishing and smoke control systems are not working, and the FDS analyzes the visibility, temperature distribution, and carbon monoxide concentration distribution through FDS. The safety was examined. As a result, it was proved that evacuation could limit the visibility, temperature, and carbon monoxide concentration in a smooth range, based on the safety standards set by relevant laws. In other words, it was possible to verify the safety of fire and evacuation for environmental energy facilities where a large amount of combustibles and fires coexist.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.1-9
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• 1994

Three recent developments made at Rensselaer in sheet material forming processes are briefly reviewed in this paper. These advances represent three broad disciplines of Process Simulation, Forming Processes, and Computer-Aided Measurement Methods. The first development deals with simple and quick computer simulation of 2D sheet forming process without depending on popular finite element analysis methods. An analytical method based on a thin shell theory accounts for bending and unbending effects, and is capable of simulating practical sheet metal forming processes under the plane strain condition. The second area is concerned with innovative methods to improve formability of sheet materials by temperature gradient forming. The drawing limit is increased by such an improved temperature gradient forming process. The third and final area deals with a totally new experimental technique to capture 3D geometry data and measure strain distributions of sheet metal parts using a digital 35mm SLR camera.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.4
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• pp.545-551
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• 1997

As the cooling energy requirement in an office building increases due to the increased internal heat gains, the effort to minimize the energy consumption through efficient operation of existing HVAC systems will be beneficial. In this study, one of the energy conserving efforts in an office building, operational strategies of Economizer Cycle Control have been investigated through DOE-2.1E computer simulation. The findings can be summarized : 1) Economizer Cycle Control saves energy throughout the year, 2) Econo-Limit-T must be applied seasonally based on the outside and return air conditions, 3) use of Enthalpy control is more energy efficient than that of Temperature control.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1438-1449
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• 1988

An analysis of radiative heat transfer has been conducted on axisymmetric finite cylindrical media. It is assumed that the temperature in the media is uniformly distributed and the boundaries are diffusely emitting and reflecting at a constant temperature. The scattering phase function is represented by the delta-Eddington approximation to account for highly forward scattering by particulates just as in the combustion system. Exact numerical solutions are obtained by Gaussian quadrature method and compared with P-1 and P-3 approximation solutions to verify their engineering application limit. The effects of optical thickness, scattering albedo, wall emissivity and aspect ratio are investigated. The results show that P-3 approximation is found to be in good agreement with the exact solution.

• Proceedings of the KIEE Conference
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• summer
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• pp.1073-1075
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• 2004

Permanent magnet high-speed machines are small size compared with general motor of the same power and so must minimize generating heat, as well rotor structure is simple and strong for born centrifugal force. Especially, Material of each part is given thermal limit therefore temperature distribution vary important. In this paper, heat transfer coefficient of permanent magnet high-speed machines with 5-kW 40,000 rpm is calculated and temperature distribution due to power loss is predicted by finite element analysis.

• Journal of the Korean Professional Engineers Association
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• v.33 no.1
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• pp.75-82
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• 2000

299 chemical analyses are used to study the characteristics of mineral and thermal waters in South Korea. Even though the concentration of chemical components in thermal waters are generally very low, mineral waters having components more than 1,000 ppm of dissolved total solid(TDS) are reached up to 1975 of total analyses data, In Germany, Japan or some other countries, mineral and thermal waters are defined not only by water temperature, but also by chemical components. The principle of Law in Japan is also almost same with the German regulations. However, the Law for thermal spring In Korea permit thermal water to be qualifiled only by water temperature. For including chemical characters into the regulations or Law of thermal spring, the limit values of TDS and other 9 micro components related to mineral and thermal waters was selected through this study.

• Bulletin of the Korean Chemical Society
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• v.9 no.2
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• pp.106-108
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• 1988

The effects of surfactants, CTAB, SDS, and TX-100, on the fluorescence emission intensity of Be-morin complex was studied in terms of pH, temperature, added electrolyte, and concentration of surfactants. The ionic surfactants decreased the fluorescence intensity of the complex. However, the addition of TX-100 caused a substantial increase in the fluorescence intensity without spectral shift, by which means the detection limit of Be was obtained to be 0.3 ppb. Optimum pH for Be determination was near 9.6 and the fluorescence intensity showed a continuous decline with the increase of temperature. Nitrate ion lowered the fluorescence intensity considerably. Mechanism of the interference remains to be elucidated.

• Nuclear Engineering and Technology
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• v.41 no.9
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• pp.1191-1204
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• 2009

In this study, a CFD methodology is employed to address the problem of the prediction of the flow in a T-junction. An Unsteady Reynolds Averaged Navier-Stokes (URANS) approach has been selected for its low computational cost. Moreover, Unsteady Reynolds Navier-Stokes methodologies do not need complex boundary formulations for the inlet and the outlet such as those required when using Large Eddy Simulation (LES) or Direct Numerical Simulation (DNS). The results are compared with experimental data and an LES calculation. In the past, URANS has been tried on T-junctions with mixed results. The biggest limit observed was the underestimation of the oscillatory behavior of the temperature. In the present work, we propose a comprehensive approach able to correctly reproduce the root mean square (RMS) of the temperature directly downstream of the T-junction for cases where buoyancy is not present.