• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.524-531
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• 2001

The temperature and humidity distribution in a dry room are studied numerically by using standard$\kappa-\varepsilon$ turbulence model. In order to evaluate effective heat and moisture ventilation characteristics inside the room, the heat removal capacity and moisture exhaust efficiency are introduced. An effective ventilation control is analyzed by evaluating quantitatively temperature and humidity distributions. It was found that the mean absolute humidity inside the room was almost constant with approximately 0.1905g/kg air regardless of the models and the heat generation rates. This was believed that the moisture generation by workers was relatively small. 40% improvement of the critical decay time was achieved, through the modifications of design variables.

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.279-286
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• 2004

This study observed the temperature and humidity within the green zone to understand the effect that land coverage and the structure of forests have on the relief of micro-climate control. Based on this set of data, this study interpreted, through the regression analysis, the relevance of land coverage of the green zone with temperature and distribution of humidity, as well as the amount of green with the relief of microclimate control. The results of the study demonstrated that high temperature regions were formed in barren areas, and low temperature regions in forests or near the water. In particular, low temperature was found in areas covered with tall and small trees, the water surrounded by forests and areas enclosing small rivers. Furthermore, mechanisms causing low temperature were, among others, the ratio of land coverage (forest, grassland, water). In fact, the temperature reduction effect varied in accordance with the types and ratios of the land coverage. Humidity also showed a close correlation with the distribution of temperature high temperature areas had low humidity and low temperature areas had high humidity. Such a phenomenon.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1002-1007
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• 2008

The floor structure of railway vehicle can deflect and warp due to variation of temperature and humidity at the inside and outside of vehicle. In this study, its temperature and humidity characteristics was investigated experimentally for beam and plate specimen and numerically for the floor structure assembly. The temperature and humidity characteristics of a part were measured and the deformation and stress distribution of the floor structure were calculated using a commercial software. And the warp deformation of the plywood was measured experimentally. The results show that the temperature and humidity effects on the floor structure are the important factor to decide the strength and the quality of the floor structure of railway vehicles.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.853-856
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• 2005

A low water/cement ratio leads to autogenous shrinkage of cement paste at an early age. This autogenous shrinkage is related to the change of relative humidity in the pore structure that is formed during the hydration process. The relationship between autogenous shrinkage and relative humidity change are relatively well defined today, but the effects of temperature on autogenous shrinkage, relative humidity, and pore structures have been studied less systematically. This study focused on correlating alterations of these properties of cement paste hydrated at constant temperatures of 20, 40, and $60^{\circ}C$. The test results clearly indicate that increasing curing temperature resulted in increased porosity, particularly for pores between 5 to 50 nm as measured by MIP, and increased autogenous shrinkages, as a consequence of a reduction of relative humidity at early ages.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.195-196
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• 2019

The temperature and relative humidity in concrete change with the passage of time depending on factors such as compressive strength. They are also different depending upon internal depth of concrete. In this study, we have measured the change of the temperature and relative humidity in the concrete for two years to act as the parameters to evaluate the concrete durability and effective maintenance.

• Architectural research
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• v.14 no.4
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• pp.153-161
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• 2012

This paper presents an integrated procedure to predict the temperature and moisture distributions in hardening concrete considering the effects of temperature and aging. The degree of hydration is employed as a fundamental parameter to evaluate hydro-thermal-mechanical properties of hardening concrete. The temperature history and temperature distribution in hardening concrete is evaluated by combining cement hydration model with three-dimensional finite element thermal analysis. On the other hand, the influences of both self-desiccation and moisture diffusion on variation of relative humidity are considered. The self-desiccation is evaluated by using a semi-empirical expression with desorption isotherm and degree of hydration. The moisture diffusivity is expressed as a function of degree of hydration and current relative humidity. The proposed procedure is verified with experimental results and can be used to evaluate the early-age crack of hardening concrete.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.5
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• pp.397-403
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• 2015

In this study, water distribution inside a proton exchange membrane fuel cell (PEMFC) was measured experimentally. Water distribution is non-uniform because of vigorous chemical reaction and mass transport and has been difficult to measure experimentally. Therefore, much research relied on indirect measuring methods or numerical simulations. In this study, several mini temperature-humidity sensors were installed at the channel for measuring temperature and humidity of the flowing gas throughout the channel. Only one of two electrode channels was humidified externally, and the humidity distribution on the other side was measured, enabling the observation of water transport characteristics under various conditions. Diffusion through the membrane became more vigorous as the temperature of the humidifier rose, but at high current density, electro-osmotic drag became more effective than diffusion.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.2
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• pp.33-38
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• 2003

In order to design the high strength corrugated fiberboard containers for agricultural products that can be used for the cold chain system, a large number of individual boxes were placed in various humidity environments at two different temperature of 5 and $20^{\circ}C$. The results indicated that temperature changes do not effect on physical strength of corrugated fiberboard containers as much as humidity changes did. The main conclusion from this study was that compression strength of corrugated fiberboard containers dropped significantly at high humidity condition, but the rates varied depending on the number of walls, temperature, and perimeter of containers. The packaging designer must consider the corrugated fiberboard boxes are also greatly affected by dimensional variations such as the length versus width ratio. Based on this study, water-resistant board would not be necessary if the ambient relative humidity does not reach to a critical point, 85 percent in the cold chain system. However, the designer must count for the unexpected fluctuation of rotative humidity resulting in severe loss of the compression strength of corrugated fiberboard container.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.215-224
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• 2009

A survey on the actual state of heating, cooling, ventilation, and air-flow and experimental measurement of temperature and humidity distribution in tomato greenhouse were performed to provide fundamental data required in the development of air-flow control technology. In single-span plastic houses, which account for most of 136 tomato greenhouses surveyed, roof windows, ventilation and air-flow fans were installed in a low rate, and installation specs of those facilities showed a very large deviation. There were no farms installed greenhouse cooling facilities. In the hot air heating system, which account for most of heating type, installation specs of hot air duct showed also a large deviation. The exhaust air temperature and wind speed in hot air duct also were measured to have a big difference depending on the distance from the heater. We are using the maximum difference as indicator to determine whether temperature distribution is uniform. However if the temperature slope is not identical in greenhouse, it can't represent the uniformity. We analyzed relation between the maximum difference and the uniformity of temperature and humidity distribution. The uniformity was calculated using the mean and standard deviation of data from 12 measuring points. They showed high correlation but were represented differently by linear in the daytime and quadratic in the nighttime. It could see that the uniformity of temperature and humidity distribution was much different according to greenhouse type and heating method. The installation guidelines for ventilation and air-flow fan, the spread of greenhouse cooling technology for year-round stable production, and improvement of air duct and heating system, etc. are needed.

• Journal of Power Electronics
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• v.15 no.3
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• pp.841-848
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• 2015

As a vital part of renewable energy and electrical traction, power converters are supposed to have high reliability and good performance. However, power semiconductors produce considerable heat when the power converter works, which results in high junction temperatures that lower the reliability and performance of the power semiconductors. Many studies show that ambient humidity has a significant effect on power devices, but the influence of high humidity on junction temperatures has yet to be studied. Therefore, this paper presents a thermal model for power converters in moist air to obtain the junction temperature increase, which is utilized for the power converter used in a Switched Reluctance Motor System. Simulation results show that the law of converter temperature distribution is independent of the relative humidity in the case of fixed ambient temperature, whereas the temperature in the power converter decreases as the ambient relative humidity increases. These simulation results are validated with the experimental results.