• Journal of the Microelectronics and Packaging Society
• /
• v.18 no.2
• /
• pp.11-15
• /
• 2011

Heat transfer equation is first reviewed and then governing equation of moisture diffusion. Analogy scheme is applied to analysis the moisture absorption problem of polymers. It make possible to numerically analyze the diffusion problem for single medium by using commercial finite element code if it is under the isothermal loading condition. It is extended to special multimaterial system by introducing pressure ratio function, whose moisture characteristics of materials are proportional to temperature only. The weight changes of silicon-nonconductive-polymer joint model due to moisture absorption is measured and been very close to the numerical results as for single media with boundary condition with zero concentration, but yields numerical errors as for multisystem media.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2017.05a
• /
• pp.246-247
• /
• 2017

In this study, it reviewed the effect of moisture migration in concrete with heating rate on concrete spalling. Concrete specimens with compressive strength 30MPa and 110MPa are used and its size is □100×100×h200mm. And, two kinds of heating rate are set such as IS0 834 and 1℃/min. As a result, in the concrete specimen exposed to ISO 834 standard heating condition, moisture could migrate through pore network and surface concrete pieces fall out by generating moisture clog near the surface in 110MPa concrete specimen. Meanwhile, In the case of concrete specimens exposed to 1℃/min. heating condition, it is appeared that moisture could not migrate because temperature is distributed uniformly. Therefore, surface spalling is not occurred with low heating rate. However, in the case of 110MPa concrete specimen is exploded even though it heated by low heating rate.

• Korean Journal Plant Pathology
• /
• v.13 no.2
• /
• pp.100-104
• /
• 1997

Influence of the moisture content in soils was examined on population variations of soil microbes, including Cylindrocarpon destructans causing root rot of ginseng, in vivo and under the field condition. Fungal populations decreased in soils treated with various moisture contents in vivo as days after the treatment in creased, but there was not a significant difference in the population among other treatments except 135% moisture content (flooding) at 15 weeks after the treatment. In flooded soils populations of total fungi and C. destructans were reduced to 1/10 and 1/50 of initial populations, respectively. There was, however, a little difference in the population of total bacteria or Actinomycetes between before and at 15 weeks after flooding. On the other hand, population variations of bacteria and Actinomycetes were much greater than those of fungi at different intervals after the moisture treatment. Variations of microbial populations in flooded soils under the field condition were similar to those in vivo. Especially, populations of Fusarium and pectolytic bacteria in flooded soils were reduced to 1/100 of populations in nonflooded soils at 170 days after treatment.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2349-2351
• /
• 1999

In this paper, the variable absorption rates and DC dielectric breakdown strength of epoxy composites were measured at boiling absorption condition in order to observe the influences of moisture in out door use. Also, in order to improve withstand voltage properties at moisture absorbtion condition. IPN (interpenetrating polymer network) method which had been already reported, was introduced and the influence was investigated. As a result, it was confirmed that the moisture absorption rate was increased and DC dielectric breakdown strength was degraded with boiling time and filler content increasing. On the other hand, it was confirmed that moisture absorption rate and DC dielectric breakdown strength degrading rate were lowered by the improvement of adhesion strength In IPN specimens.

• Journal of Ginseng Research
• /
• v.7 no.1
• /
• pp.74-79
• /
• 1983

Effect of soil moisture on content and partition of mineral nutients in panax ginseng (2 years old) was investigated. Similarity was found between N and p, Ca and Mg, K and Fe. Mn and Zn were quite different each other and from others. Nutrient partition was affected more by nutrient content than by dry matter. Under suboptimal moisture condition partition to shoot was inhibited in order of Mg, Zn, Ca, Mg, N and P while accelerated in odor of Fe. K and Mn. Under supraoptimal moisture condition Partition to shoot was inhibited in order of Zn, Fe, K, and Ca, while accelerated in order of Mg, N, Mn and p.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.7
• /
• pp.158-167
• /
• 1999

Heat and moisture transfer associated with porous materials are investigated. The heat and moisture transfer in porous materials caused by the interaction of moisture gradient, temperature gradient, conduction, and evaporation are considered. The variations of temperature and moisture not only change the volume but also induce the hygro-thermal stress. The finite element formulation for solving the temperature and moisture transfer as well as the associated hygro-thermal stresses is developed. In order to verify the finite element formulation, the heat and moisture moving boundary problem in a half space and the hygro-thermo-mechanical problem in an infinite plate with a circular hole are analyzed. Temperature profile, moisture profile, and hygro-thermal stresses are compared with those of analytic solution and other investigator. Good agreements are examined

• Journal of the Korea Furniture Society
• /
• v.20 no.6
• /
• pp.599-604
• /
• 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.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.26 no.2
• /
• pp.47-58
• /
• 1984

The study results of the mosture consumption character and irrigation effect of tomato, red pepper and chinese cabbage, in case the soil moisture is kept with different moisture content by the soil properties(loam, sandy loam, sand), are summarized as follows: 1. The available rainfall under bare soil condition had an order of sand>sandy loam> loam and their average was 64.2%. 2. Total moisture consumption under bare soil condition had an order of loam>sandy loam>sand and their average was 4.2mm. 3. The amount of irrigated water to keep certain soil moisture under bare soil condition showed minimum in sand and maximum in loam. It is considered because the capillary phenomenon was more developed in loam. 4. Total moisture consumption of tomatoes under premature cultivation showed 925mm in maximum and had on order of loam>sandy loam>sand. In the aspect of re-irrigation point, it had an order of PF 1.5> PF 1.7>PF 2.1. In case the twenty years's drought frequency was taken into account, the target amount of irrigation water meeded for premature cultivation was 916mm and its average daily moisture consumption was 10.8mm. 5. Total moisture consumption of red pepper under open cultivation showed 1145mm in maximum and had an order of loam>Sandy loam>sand. In the aspect of re-irrigation frequency was taken into consideration the target amount of irrigation water was 1,174.8mm and its average daily moisture consumption was 8.0mm. 6. Total moisture consumption of autumn chinese cabbages was 349mm in maximum and had an order of loam>sandy loam>sand. In the aspect of re-irrigation point, it had an order of PF 1.5>PF 2.1>PF 2.7. In case the twenty year's drought frequency was taken into account, the target amount of irrigation water needed for chinese cabbage cultivation was 259.5mm and its average daily moisture consumption was 6.5mm. 7. It is effective to keep the soil moisture of tomato from PF 1.5 to PF 2.1 in loam and the soil moisture control was effective in sandy loam than red pepper and chinese cabbage. In sand, the production was severaly decreased and the re-irrigation point of PF 1.5 was effective.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.334-334
• /
• 2017

Unstable soil moisture conditions often negatively affect the emergence, seedling establishment, and growth uniformity at the initial stage, and then reduce the grain yield and biomass in direct seeding cultivation for rice in rainfed fields. Therefore it is important to develop a technique to increase the rapid and stabilized seedling establishment and improve the uniformity of initial growth after sowing. This study aims to confirm results on seed priming effect of indoor using petri dish experiments can be reproduced in the field using container at Ghana. Twenty-seven rice varieties including of Oryza sativa L. and O. glaberrima Steud. were used in this study. The experiments using petri dish and container with different soil moisture conditions (5%, 10%, 15%, 20%) were compared. As a result, a significant positive correlation was found between the germination time uniformity in the primed seed of petri dish and emergence time uniformity in the primed seed of container in 10% and 15% soil moisture condition. A significant positive correlation was found between the germination time uniformity in the primed seed of petri dish and plant height in the primed seed of container in 10% soil moisture condition in O. glaberrima. This study concluded that the priming effect in petri dish demonstrate those in container in the field condition of Ghana in 10% and 15% soil moisture condition during seedling stage.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.53-53
• /
• 2017

Unstable soil moisture conditions often negatively affect the emergence, seedling establishment, and growth uniformity at the initial stage, and then reduce the grain yield and biomass in direct seeding cultivation for rice in rainfed fields. Therefore it is important to develop a technique to increase the rapid and stabilized seedling establishment and improve the uniformity of initial growth after sowing. This study aims to confirm results on seed priming effect of indoor using petri dish experiments can be reproduced in the field using container at Ghana. Twenty-seven rice varieties including of Oryza sativa L. and O. glaberrima Steud. were used in this study. The experiments using petri dish and container with different soil moisture conditions (5%, 10%, 15%, 20%) were compared. As a result, a significant positive correlation was found between the germination time uniformity in the primed seed of petri dish and emergence time uniformity in the primed seed of container in 10% and 15% soil moisture condition. A significant positive correlation was found between the germination time uniformity in the primed seed of petri dish and plant height in the primed seed of container in 10% soil moisture condition in O. glaberrima. This study concluded that the priming effect in petri dish demonstrate those in container in the field condition of Ghana in 10% and 15% soil moisture condition during seedling stage.