• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.470-477
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• 2010

This paper is a part of developing a program that predicts the surface temperature and the IR images of ground objects by considering solar irradiation and atmospheric convection. The thermal modeling is essential for identifying objects on the scenes obtained from the remote sensing. And the temperature distribution on the objects is necessary to obtain their infrared images in contrast to the background. We considered the composite heat transfer modes including conduction, convection and spectral solar radiation incident on the objects within a scene to calculate the surface temperature distribution. The surface temperatures obtained by using the S/W developed in this study(Silhouette) and a commercial S/W(SE-Workbench-IR) are computed and compared each other. Results obtained by using the S/W developed in this study(Silhouette) show fairly good agreement with those obtained by the SE-Workbench-IR.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2104-2113
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• 2002

A finite element model is developed for the process of squeeze casting of metal matrix composites (MMCs) in cylindrical molds. The fluid flow and the heat transit. are fundamental phenomena in squeeze casting. To describe heat transfer in the solidification of molten aluminum, the energy equation is written in terms of temperature and enthalpy are applied in an axisymmetric model which is similar to the experimental system. A one dimensional flow model simulates the transient metal flow. A direct iteration technique was used to solve the resulting nonlinear algebraic equations, using a computer program to calculate the enthalpy, temperature and fluid velocity. The cooling curves and temperature distribution during infiltration and solidification were calculated fer pure aluminum. Experimentally, the temperature was measured and recorded using thermocouple wire. The measured time-temperature data were compared with the calculated cooling curves. The resulting agreement shows that the finite element model can accurately estimate the solidification time and predict the cooling process.

• Journal of Environmental Science International
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• v.28 no.2
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• pp.235-248
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• 2019

The purpose of this study is to quantitatively analyze the effects of a restoration project on the decrease in the temperature in the surrounding areas. The thermal environment characteristics of the investigation area were analyzed using the meteorological data from the Busanjin Automatic Weather System which is closest to the target area. The terrain data of the modeling domain was constructed using a digital map and the urban spatial information data, and the numerical simulation of the meteorological changes before and after the restoration of the stream was performed using the Envi-met model. The average temperature of the target area in 2016 was $15.2^{\circ}C$ and was higher than that of the suburbs. The monthly mean temperature difference was the highest at $1.1^{\circ}C$ in November and the lowest in June, indicating that the temperatures in the urban areas were high in spring and winter. From the Envi-met modeling results, reductions in temperature due to stream restoration were up to $1.7^{\circ}C$ in winter, and decreased to $3.5^{\circ}C$ in summer. The effect of temperature reduction was seen in the entire region where streams are being restored.

• Smart Structures and Systems
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• v.30 no.3
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• pp.245-253
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• 2022

A two-layer beam consisting of an elastoplastic layer and a functional layer made of shape memory alloy (SMA) TiNi is considered. Constitutive relations for SMA are set by a microstructural model capable to calculate strain increment produced by arbitrary increments of stress and temperature. This model exploits the approximation of small strains. The equations to calculate the variations of the strain and the internal variables are based on the experimentally registered temperature kinetics of the martensitic transformations with an account of the crystallographic features of the transformation and the laws of equilibrium thermodynamics. Stress and phase distributions over the beam height are calculated by steps, by solving on each step the boundary-value problem for given increments of the bending moment (or curvature) and the tensile force (or relative elongation). Simplifying Bernoulli's hypotheses are applied. The temperature is considered homogeneous. The first stage of the numerical experiment is modeling of preliminary deformation of the beam by bending or stretching at a temperature corresponding to the martensitic state of the SMA layer. The second stage simulates heating and subsequent cooling across the temperature interval of the martensitic transformation. The curvature variation depends both on the total thickness of the beam and on the ratio of the layer's thicknesses.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4095-4101
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• 2022

Following the climate-related disasters considered by several efforts, the nuclear capacity needs to double by 2050 compared to 2015. So, it is reasonable to investigate global warming incorporated with the fuzzy set theory for nuclear energy consumption in the aspect of fuzziness and nonlinearity of temperature variations. The complex modeling is proposed for the enhanced assessment of climate change where simulations indicate the degree of influence with the Boolean values between 0.0 and 1.0 in the designed variables. In the case of OIL, there are many 1.0 values between 20^th and 60^th months in the simulations where there are 10 times more for a 1.0 value in influence. Hence, the temperature variable can give the effective time using this study for 100 months. In the analysis, the 1.0 value in NUCLEAR means the highest influence of the modeling as the temperature increases resulting in global warming. In detail, the first influence happens near the 8th month and then there are four times more influences than effects in the early part of the temperature mitigation. Eventually, in the GLOBAL WARMING, the highest peak is around the 20^th month, and then it is stabilized.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.113-119
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• 1998

Spatial patterns of soil temperature on sloping lands are related to the amount of solar irradiance at the surface. Since soil temperature is a critical determinant of many biological processes occurring in the soil, an accurate prediction of soil temperature distribution could be beneficial to agricultural and environmental management. However, at least two problems are identified in soil temperature prediction over natural sloped surfaces. One is the complexity of converting solar irradiances to corresponding soil temperatures, and the other, if the first problem could be solved, is the difficulty in handling large volumes of geo-spatial data. Recent developments in geographic information systems (GIS) provide the opportunity and tools to spatially organize and effectively manage data for modeling. In this paper, a simple model for conversion of solar irradiance to soil temperature is developed within a GIS environment. The irradiance-temperature conversion model is based on a geophysical variable consisting of daily short- and long-wave radiation components calculated for any slope. The short-wave component is scaled to accommodate a simplified surface energy balance expression. Linear regression equations are derived for 10 and 50 cm soil temperatures by using this variable as a single determinant and based on a long term observation data set from a horizontal location. Extendability of these equations to sloped surfaces is tested by comparing the calculated data with the monthly mean soil temperature data observed in Iowa and at 12 locations near the Tennessee - Kentucky border with various slope and aspect factors. Calculated soil temperature variations agreed well with the observed data. Finally, this method is applied to a simulation study of daily mean soil temperatures over sloped corn fields on a 30 m by 30 m resolution. The outputs reveal potential effects of topography including shading by neighboring terrain as well as the slope and aspect of the land itself on the soil temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.59-68
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• 1995

Composting facilities are operated with air and moisture control. Composting effects on two operating factors was analysed changing aeration rate with and without water addition to maintain the optimun moisture level. Though the composting facilties are provided with appropriate surroundings for compositing, operating temperature is set for decomposition rate. Accordingly control of decomposition phases was analysed by modeling the process of high and low decomposition phases with various operating temperature. A composting model of "The Library of Compost Engineering Software" developed by Roger T. Haug Inc. in U.S.A. was applied in modeling. As result of this study, operation with optimum moisture has more sensitive temperature to aeration fluctuation and lead to higher reaction rate with lower aeration than operation with poor moisture. Decomposition rate in composting facilities depend on slow decomposition phase because high rate decomposing substances already have been decomposed before entire process is not completed. In order to enhance decomposition rate of organics, effective decomposition in slow decomposition phase needs to be focused.

• Journal of Climate Change Research
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• v.8 no.2
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• pp.109-123
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• 2017

The effects of recent climate change on hydrological systems could affect the Winter Olympic Games (WOG) because the event is dependent on suitable snow and ice conditions to support elite-level competitions. We investigate the long-term variability and change in winter total precipitation (P), snowfall water equivalent (SFE), and ratios of SFE to P during the period 1973/74~2015/16 in Gangwon province. The climatological percentages of SFE relative to winter total precipitation were 71%, 28%, and 44% in Daegwallyeong, Chuncheon, and Gangneung, respectively. The winter total P, SFE, and SFE/P has decreased (but not significantly), although significant increases of winter maximum and minimum temperature were detected at a 95% confidence level. Notably, a significant negative trend of SFE/P at Daegwallyeong in February, the month of the WOG, was attributable to a larger decrease in SFE related to the increases in maximum and minimum temperature. Winter wet-day minimum temperatures were warmer than climatological minimum temperatures averaged over the study period. The 20-year return values of daily maximum P and SFE decreased in Yongdong area. Since the SFE/P decrease with increasing temperature, the probability of rainfall rather than snowfall can increase if global warming continues.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1995.10b
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• pp.98-103
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• 1995

In this paper, a method is presented for finding an optimal temperature control pattern in microwaveoven using genetic algorithm. Power spectrum of temperature variance of charcoal is obtained and oven system modeling with fuzzy-neural-network is explained. Fan on/off timing is converted to strings in gene pool and then genetic iterations make the power spectrum of simmulated temperature variance of microwave oven closer to that o charcoal.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.10 no.2
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• pp.7-12
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• 2014

Government has recently restricted heating and cooling set temperatures for the commercial and public buildings due to increasing national energy consumption. The goal of this paper is to visualize a future two way indoor set temperature control impact on building energy consumption by using TRNSYS simulation modeling. The building was modelled based on the twin test cell with the same dimension. Air source ground coupled heat pump performance data has been used for modeling by TRNSYS 17. Daejeon weather data has been used from Korea Solar Energy Society. The heating set temperature in the reference room is $24^{\circ}C$ as well as the target room set temperature are $23^{\circ}C$, $22^{\circ}C$, $21^{\circ}C$ and $20^{\circ}C$. The cooling set temperature of the reference room is also $24^{\circ}C$ as well as the target room set temperature of $25^{\circ}C$, $26^{\circ}C$, $27^{\circ}C$ and $28^{\circ}C$. For the air source heat pump system, heating season energy consumption is $35.52kWh/m^2y$ in the reference room. But the heating energy consumption in the target room is reduced to 7.5% whenever the set temperature decreased every $1^{\circ}C$. The cooling energy consumption in the reference room is $4.57kWh/m^2y$. On the other hand, the energy consumption in the target room is reduced to 22% whenever the set temperature increased every $1^{\circ}C$ by two way controller. For the geothermal heat pump system, heating energy consumption in the reference room is reduced to 20.7%. The target room heating energy consumption is reduced to 32.6% when the set temperature is $22^{\circ}C$. The energy consumption in the target room is reduced to 59.5% when the set temperature is $26^{\circ}C$.