• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.932-941
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• 1993

High moisture content of barley seeds, which were carried to the laboratory within 10 minutes after harvest, were stored in air tight bottle at constant temperature, and the individual moisture contents the grains were measured at predecided tim intervals. The theory of predicting the moisture movement between two kinds of different moisture content grains was tried to apply to the prediction of the moisture distribution and tried to apply to the prediction of the moisture distribution and the comparison of the predicted values with the observed dta showed the good suitability of the theory. The shape of the moisture distribution predicted form the theory were similar to the observed ones for the temperature range of 10 to $50^{\circ}C$. This study will be useful in designing the mix-storage facility or dryer.

• Journal of the Korean Wood Science and Technology
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• 제37권5호
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• pp.459-464
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• 2009

This study was conducted to find the relationship between the moisture content and basic density of green lumber and the final moisture content of kiln dried lumber. The possibility of using a ultrasonic nondestructive testing technology was investigated. Four matched 2-foot long boards were kiln-dried for 12, 24, 36 and 48 hours. Twenty three slices were cut to examine the distribution of moisture content along the length. It was revealed that the green weight was a better estimator of the final moisture content of the kiln-dried board than the green moisture content. The standard deviations of the moisture contents of the slices were not correlated with the final moisture contents of the kiln-dried boards. The two ultrasonic devices used for this study were apparently good tools for NDT.

• 한국가구학회지
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• 제20권6호
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• pp.599-604
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• 2009

For the search of unified law of moisture movement in wood, moisture distribution of Korean red pine at non-steady state was investigated. We assume that the equilibrium moisture content (EMC) in wood depends on only temperature and relative humidity, it can be control in temperature and humidity chamber. If temperature is constant and humidity or vapor pressure is changed with sin curve shape at adequate cycles, EMC in chamber can be changed as well with sin-curve shape. The setup condition of a non-steady state in humidity control chambers is a constant temperature at $20^{\circ}C$ and 15+10 sin ${\omega}t$ percent EMC. It can be found that the distribution of moisture in the specimen with varying relative humidity are illustrated various types. Moisture in wood is complicated and vibrates with the moisture sorption process. Considering a unified law of moisture movement in wood, it is considered that the most important fact is to search the method of precise diffusion & transfer coefficients.

• Current Research on Agriculture and Life Sciences
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• 제10권
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• pp.41-47
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• 1992

목재투습성에 관하여 다음과 같은 결과가 밝혀졌다. 1) 시편두께 0mm에 외삽한 투습저항값이 정(正)이므로 목재표면에서의 수분전달현상을 고려함이 인정되었다. 2) 목재내부의 함수율분포는 함수율 9%를 경계로 두 개의 직선으로 나타났다. 또 시편양측의 공기중 평형함수율이 9%이상일 때는 한 개의 직선으로 나타났다. 수분확산계수는 함수율 9%를 경계로 두 개의 일정한 값을 가지며, 이 값들은 오직 함수율에만 관계한다. 4) 수분이동량은 목재내의 함수율구배에 의존한다. 4) 목재의 수분전달계수는 시편두께에 의존하였다. 이 현상의 기구에 대해서는 아직 알 수 없다.

• Computers and Concrete
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• 제16권5호
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• pp.775-793
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• 2015

Moisture transport in concrete in atmospheric environment was studied in this paper. Based on the simplified formula of the thickness of the adsorbed layer, the pore-size distribution function of cement paste was calculated utilizing the water adsorption isotherms. Taking into consideration of the hysteresis effect in cement paste, the moisture diffusivity of cement paste was obtained by the integration of the pore-size distribution. Concrete is regarded as a two-phase composite with cement paste and aggregate, neglecting the moisture diffusivity of aggregate, then moisture diffusivity of concrete was evaluated using the composite theory. Finally, numerical simulation of humidity response during both wetting and drying process was carried out by the finite difference method of partial differential equation for moisture transport, and the numerical results well capture the trend of the measured data.

• Computers and Concrete
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• 제14권6호
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• pp.635-656
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• 2014

A rational estimation of moisture distribution in structural concrete is vital for predicting the possible extent and rate of progression of impending degradation processes. The paper proposes a numerical scheme for analysing the evolution of moisture distribution in concrete subjected to wetting-drying exposure caused by intermittent periods of rainfall. The proposed paradigm is based on the stage wise implementation of non-linear finite element (FE) analysis, with each stage representing a distinct phase of a typical wet-dry cycle. The associated boundary conditions have been constituted to realize the influence of various meteorological elements such as rain, wind, relative humidity and temperature on the exposed concrete surface. The reliability of the developed scheme has been demonstrated through its application for the simulation of experimentally recorded moisture profiles reported in published literature. A sensitivity analysis has also been carried out to study the influence of critical material properties on simulated results. The proposed scheme is vital to the service life modelling of concrete structures in tropical climates which largely remain exposed to the action of alternating rains.

• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.20-28
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• 2008

This study was carried out to provide the so-called circumferential slicing method for investigating radial distributions of the tangential strains and of moisture contents within the log cross section (LC) of Kalopanax pictus during indoor drying it. While the heartwood showed an almost uniform moisture content distribution in the range of about 50~55% in case of the green wood, it has gradually decreased toward the outer side, showing about 19% of moisture content difference from the innermost slice. Although the moisture gradient along the radial direction has gradually become gentle as drying progresses, the sapwood of the outer side represented the moisture contents below the fiber saturation point after 24 hours of drying while the heartwood in the inner part showed the moisture contents higher than the fiber saturation point. The pith side was laid under the tensile stress after 24 hours of drying, and then gradually decreasing toward the bark side, and showed the distribution being switched again to the tensile stress on the bark side. As the drying has progressed, this trend got more intensified, and finally showed the U-shaped distribution model after 48 hours of drying. The circumferential slice test is considered to be suitable in quantitatively determining the tangential strains and moisture content within a LC.

• Journal of the Korean Wood Science and Technology
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• 제24권1호
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• pp.75-80
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• 1996

The purpose of this study is to clarify the mechanism of moisture transfer depend on the thickness of the spruce(Picea sitchensis Carr.). Therefore, as the basic research of moisture transmission, the amount of moisture transmission and the moisture distribution in specimens and temperature of it's surfaces in vapor transmission process were investigated. The experiment was conducted in a steady state. and the moisture distribution was measured by knife cutting and weighing the specimens. The following conclusions were obtained ; 1. It can be found that distribution of moisture in the specimen can be approximated by two different straight lines intersecting at nine or ten percent moisture content. The amount of moisture movement defends on the gradient of moisture in the wood. 2. It is investigated that the wood surface moisture contents(MCs) are less for thinner specimens than for thick ones on the absorption side. On the other hand, the wood surface MCs are greater for thinner specimens than for thick ones on the desorption side. The main factor that affects the EMC of wood would be temperature when the relative humidity of atmosphere is constant. The specimen generate heat with the absorption and desorption process. In addition, the velocities of moisture transmission varied with the thicknesses of specimens. If the temperature of wood becomes greater, its MC decreases. Then the difference between surface MC and EMC of adsorption and desorption side becomes greater for thinner specimens. Therefore it is considered that the coefficients of moisture transfer decreases with the increases of the specimens' thicknesses.

• 한국수자원학회논문집
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• 제38권1호
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• pp.73-82
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• 2005

국내산지사면의 토양수분 시공간적 분포상황을 파악하기 위한 토양수분 측정법을 개발하였다. 대상유역을 정밀 측량하여 수치고도모형을 구성한 다음 흐름분배 알고리즘을 적용하였고 역측랑을 통한 대상 유역의 흐름분배 알고리즘의 유의성을 판단하였다. 이를 통한 공간적 변화의 대표성을 최대화하기 위한 장기 모니터링 시스템을 구축하였으며, 토양수분의 정확한 측정을 위해 TDR(Time Domain Reflectometry)을 이용하였다. 측정은 설마천 유역의 범륜사 우측사면에서 수행되었다. 강우사상에 의한 시공간적 토양수분의 변화 자료를 성공적으로 획득하였다. 획득된 토양수분자료는 측정시스템의 효용성과 사면유출의 과정에 대한 물리적인 과정을 나타낸다. 불연속적인 토양수분의 연직분포 양상은 사면 수문과정에서 선행흐름이나 대공극 흐름의 중요성을 의미한다.

• 콘크리트학회지
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• 제4권1호
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• pp.127-134
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• 1992

일반적으로 콘크리트 내부의 수분은 주로 중심부에 분포되어 있으며, 노출된 콘크리트의 표면은 주위의 온습도영향에 따라 건조하게 된다. 이에 따라 동일 부재내에서도 부위에 따라 함수율이 달라지게 된다. 이는 콘크리트의 내부공극에 존재하고 있는 수분의 증발과 이동으로 인하여 함수상태가 달라지기 때문이다. 이와 같이 콘크리트의 함수상태변화로 인하여 압축강도, 탄성계수, 용적변화등의 제성상이 각 부위에 따라 달라질 것으로 예상된다. 따라서, 콘크리트의 함수상태에 따른 콘크리트의 제성상을 명확히 파악함은 매우 중요하다고 판단된다. 본 연구에서는 콘크리트의 함수상태와 역학적 성상을 규명하는데 그 목적이 있다. 콘크리트의 함수량이 증가할수록 압축강도와 인장강도는 감소하나, 탄성계수는 증가한다. 본 연구에서 실험을 통하여 이와 같은 콘크리트의 성상과 함수상태와의 상관관계를 밝혔다.