• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.535-542
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• 1994

Remote sensing technique is based on the estimation of land surface characteristics from the measurement of the emitted radiation from the earth. The hydrologically related parameters studied using this approach include surface temperature, evapotranspiration, soil moisture, precipitation and snow. This study introduces a method for estimating moisture content of a bare soil from the observed and simulated brightness temperature. In a bare soil, microwave emission depends on moisture content, soil temperature, and surface roughness. The method is based on a radiative transfer model with some modifications of Fresnel reflection coefficient to take into account the effect of surface roughness. One smooth bare field and two fields with different surface roughness are prepared for the study. The results indicate that the effect of surface roughness is to increase the soil's brightness temperature and to reduce the slope of regression between brightness temperature and moisture contents.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2004.04a
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• pp.117-126
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• 2004

This paper presents a linear model for heat transfer processes in the drying cylinders and the web in papar mill. The PDE model, functions include steam temperatures, wet temperatures, moisture constents, reel speed and basis weight were derived from operation data. The changes of wet temperatures and moisture contents in the drying cylinders and wets could be described. The Transfer function can be obtained through the state space model derived from the linearized PDE model. Stability of the drying cylinder model for paper plants and analysis of characteristics of process responses for changes in input variables are investigated.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.4
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• pp.331-340
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• 2004

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The fresh air is introduced into the double slab space and passes through the opening bored into the footing beam. The air is cooled by the heat exchange with the inside surface of the double slab space in summer, and heated in winter. This system not only reduces sensible heat load of the fresh air by heat exchange with earth but also reduces latent heat load of the fresh air by ad/de-sorption of underground double slab concrete. In this paper, we used a model for evaluation of fresh air latent heat load reduction by hygroscopic of air to earth exchange system taking into account coupled heat and moisture transfer of underground double floor space. In conclusion it shows the validity of the proposed method for a design tool and the quantitative effect of the system.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1530-1535
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• 2009

Moisture evaporates, when concrete is exposed to fire, not only at concrete surface but also at inside the concrete to adjust the equilibrium and transfer properties of moisture. The equilibrium properties of moisture are described by means of water vapor sorption isotherms, which illustrate the hysteretical behavior of materials. In this paper, the prediction method of the moisture distribution inside the high strength concrete members under the high temperature is presented. Finite element method is employed to facilitate the moisture diffusion analysis for any position of member. And the moisture diffusivity model of high strength concrete by high temperature is proposed. To demonstrate the validity of this numerical procedure, the prediction by the proposed algorithm is compared with the test result of other researcher. The proposed algorithm shows a good agreement with the experimental results including the vaporization effect inside the concrete.

• KIEAE Journal
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• v.10 no.4
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• pp.75-80
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• 2010

Generally, ground-source heat pump (GSHP) systems have a higher performance than conventional air-source systems. However, the major fault of GSHP systems is their expensive boring costs. Therefore, it is important issue that to reduce initial cost and ensure stability of system through accurate prediction of the heat extraction and injection rates of the ground heat exchanger. Conventional analysis methods employed by line source theory are used to predict heat transfer rate between ground heat exchanger and soil. Shape of ground heat exchanger was simplified by equivalent diameter model, but these methods do not accurately reflect the heat transfer characteristics according to the heat exchanger geometry. In this study, a numerical model that combines a user subroutine module that calculates circulation water conditions in the ground heat exchanger and FEFLOW program which can simulate heat/moisture transfer in the soil, is developed. Heat transfer performance was evaluated for 3 different types ground heat exchanger(U-tube, Double U-tube, Coaxial).

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.641-646
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• 2001

In early-age concrete, volumetric deformations due to thermal expansion and moisture transfer are restrained by various boundary conditions, and then restraint stresses occur in proportion to developed stiffness. With increase of the age, these stresses are gradually relieved by significant relaxation behavior of early-age concrete. Therefore, it is necessary to consider the stress relaxation in order to analyze the behavior of early-age concrete more accurately. In this paper, we propose a unified algorithm which combines a relaxation model with hydration model, heat conduction model, micropore structure formation model, moisture diffusion model and mechanical properties development model and develop a finite element program based on the algorithm. The program is applied to evaluate stress development if a temperature-stress test machine (TSTM) specimen and a massive concrete structure, and then validity of the program is discussed and evaluated.

• Fibers and Polymers
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• v.4 no.4
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• pp.215-221
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• 2003

A vertical skin model with two detachable environmental chambers was developed to simulate a Human-Clothing-Environment system and to evaluate heat and moisture transport properties of textile materials under severe conditions and during transient states. The construction of the system was described and data reproducibility and accuracy of the instrument were verified by using PEG treated nonwovens. Also advantages over a traditional static type experiment were demonstrated based on a series of experiments.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.2
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• pp.1-9
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• 2009

Water binder ratio combine high-performance concrete shrinkage of less than 0.4 to determine the transformation to a total shrinkage of water to move outside and internal consumption of moisture due to drying shrinkage and autogenous shrinkage, and then, the relative humidity changes and strain to be approached by surface physics describe the relationship between self-desiccation and autogenous shrinkage was set. To verify the self-desiccation in the humidity shrinkage and humidity measurements performed, and the research model, Tazawa, CEB-FIP model than to let the measure and the most similar results in this study based on self-desiccation model, autogenous shrinkage didn't represent the linear shrinkage by the drying shrinkage of the external moving but exponential relationships, unlike with the nature and rapid in the early age properly describes the attributes in shrinkage could see. After this research to move moisture and to reflect the shrinkage model, temperature, moisture transfer, strain analysis by multi-physics model is very similar to the results of mock-up specimen measurements performed for this research, the value measured by the internal consumption of moisture, therefore self-desiccation and a multi-physics model considering autogenous shrinkage might be relevant.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.5
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• pp.53-61
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• 2003

In this study a model for the drying process in paper production plants was developed based on the mass and heat balances around drying cycles. Relationships for the heat transfer coefficients between the web and the air as well as between the drying cylinder and the web were extracted from the closed-loop plant operation data. It was found that the heat transfer coefficients could be represented effectively in terms of moisture content, basis weight and reel velocity. The effectiveness of the proposed model was illustrated through numerical simulations. From the comparison with the operation data, the proposed model represents the paper plant being considered with sufficient accuracy.

• Journal of Biosystems Engineering
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• v.37 no.2
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• pp.82-89
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• 2012

Purpose: The simulation model of a pneumatic conveying drying (PCD) for sawdust was developed and verified with the experiments. Method: The thermal behavior and mass transfer of a PCD were modeled and investigated by comparing the experimental results given by a reference (Kamei et al. 1952) to validate the model. Momentum, energy and mass balance, one dimensional first order ordinary differential equations, were coded and solved into Matlab V. 7.1.0 (2009). Results: The simulation results showed that the moisture content reduced from 194% to 40% (dry basis), air temperature decreased from $512^{\circ}C$ to $128^{\circ}C$ with the particle residence time of 0.7 seconds. The statistical indicators, root mean square error and R-squared, were calculated to be 0.079, and 0.998, respectively, between the measured and predicted values of moisture content. The relative error between the measured and predicted values of the final pressured drop, air temperature, and air velocity were only 8.96%, 0.39% and 1.05% respectively. Conclusions: The predicted moisture content, final temperature, and pressure drop values were in good agreement with the experimental results. The developed model can be used for design and estimation of PCD system for drying of wood dust particles.