• Title/Summary/Keyword: Moisture condition

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Determination of Microwave Dielectric Properties of Grain by Free Space Transmission Method (자유공간 전송방법을 이용한 마이크로파 유전특성연구)

  • 김종헌;김기복;노상하
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.04a
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    • pp.233-235
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    • 1997
  • A free sparse transmission method using X-band standard gain horn antenna is applied to measure the attenuation and phase shift of microwave signal through the wetted grain such as rough rice, brown rice and barley. The moisture content of grain varied from 11 to 25% based on its wetted condition. The dielectric constant and loss factor, which depend on the moisture content of the wetted grain are obtained from the measured attenuation and phase shift by vector network analyzer. The measured values of dielectric constants as a function of moisture density are compared with values of those obtained using the predicted model for estimating dielectric constants of grain.

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Performance Evaluation of Water Vapour Adsorption/Desorption Property for a Building Material by Mock up Test (실물시험을 통한 흡방습 건축자재의 성능평가)

  • Kim, Hea Jeong;Song, Kyoo Dong;Lee, Yun Gyu
    • KIEAE Journal
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    • v.9 no.2
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    • pp.53-58
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    • 2009
  • There are increasing developments and uses of functional building materials are recently developed and introduced to the test method for the materials. Especially, moisture problem has a major role are also being established in indoor air quality problems. The purpose of this study is to evaluate the water vapour adsorption/desorption property of a ceiling material. The variation of the temperature and moisture were measured with the application materials by mock up test based on JIS 1470-1. The result shows that water vapour adsorption/desorption property of ceiling material is appeared in changes of moisture adsorption and desorption in comparison with that of a general ceiling material. Therefore, in case of decreasing and increasing in humidity, these materials can be used as an finishing material to sustain comfort condition.

Preliminary Study of Bioremediation in Diesel Contaminated Soil (디젤 오염토양의 생물학적 복원에 관한 기초연구)

  • 김선영;권수열;이상훈
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.11a
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    • pp.167-170
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    • 2000
  • The purpose of study is to evaluate the effects of physical parameters on diesel biodegradation in diesel contaminated soil. The parameters applied are concentration, temperature, moisture contents, electron acceptor(O$_2$). The results of this study showed that diesel were degraded faster at high temperature and moisture contents than at low temperature and moisture content. However concentration effect study indicates that diesel were more faster degraded at low concentration than at high concentration. The results of electron acceptor test showed concentration of oxygen did not affect the biodegradation rate of diesel in oxygen condition(10, 20%) of this study.

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A Study on the variations of tracking resistance of outdoor Epoxy composites due to moisture absorption aging (흡습열화에 따른 옥외용 에폭시 복합체의 내트래킹성 변화에 관한 연구)

  • 김탁용;이덕진;가출현;김명호;박창옥;김재환
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.526-528
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    • 1999
  • Epoxy resin has been used as matrix resin of advanced composites owing to ideally suitable properties and inherent physical and chemical properties for electrical and electronic insulation In this paper, in order to evaluate the performance of epoxy composites for out door insulation, variations of tracking resistance were investigated on the moisture absorption aging condition. Also, IPN methods were introduced in order to improve performance for out door use. As a result, it was confirmed that tracking resistance were degraded with boilling time. But, it was confirmed that specimen of IPN structure and KC-335 have the better tracking resistance properties than SIN structure by moisture absorption aging

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Drying Characteristics of 25 kW Class Industrial Dryer Adopting Mat Type Premixed Catalytic Burner (매트 형태의 예혼합 촉매 버너를 활용한 25 kW급 건조기의 성능 특성)

  • Ahn, Joon;Kim, Hyouck-Ju;Song, Kwang-Sup;Choi, Kyu-Sung;Song, Dae-Seok
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2856-2861
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    • 2008
  • A catalytic burner has been developed to utilize thermal energy from the fossil fuel without nitrogen oxides (NOx) emission. The burner is shaped into a mat to maximize the heating surface. Premixed combustion has been developed to be used in a closed chamber, such as a radiation type industrial dryer. The burner yields the thermal energy in the form of thermal radiation in the infrared regime, which is proved to be effective to dry organic substances for low moisture condition. Thermal efficiency including the sensible heat is better correlated to the moisture compared to the dry rate.

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Lateral Behavior of Sin811e and Group Piles in Sand (사질토 지반에서 말뚝의 수평거동)

  • 김영수;김병탁
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.10a
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    • pp.3-44
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    • 1999
  • This paper discusses the lateral behavior of single and group piles in homogeneous and non-homogeneous(two layered) soil. In the single pile, the model tests were conducted to investigate the effects on ratio of lower layer height to embedded pile length, ratio of soil modules of upper layer to lower layer, boundary rendition of pile head and tip, embedded pile length, pile construction condition, ground condition with saturate and moisture state in Nak-Dong river sand. Also, in the group pile, the model tests were to investigate the effects on spacing-to-diameter ratio of pile, pile array, ratio of pile spacing, boundary condition of pile head and tip, eccentric load and ground condition. The maximum bending moment and deflection induced in active piles were found to be highly dependent on the relative density, pile construction condition, boundary condition of pile head and tip. Based on the results obtained, it was found that the decrease of lateral bearing capacity in saturated sand was in the range of 31% - 53% as compared with the case of dry sand. Also, in the group pile, a spacing-to-diameter of 6.0 seems to be large enough to eliminate the group effect for the case of relative density of 61.8%, and 32.8%, and then each pile in such a case behaves essentially the same as a single pile. In this study, the program is developed by using the modified Chang method which used p - y method and the exact solution of governing equation of pile and it can be used to calculate the deflection, bending moment and soil reaction with FDM in non-homogeneous soil. In comparing the modified Chang method with field test results, the predict results shows better agreement with measured results in field tests.

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Identification of Chalkiness Development of Milled Waxy Rice Grains with Harvest Times and the Moisture Contents (찰벼 수확시기 및 건조정도에 따른 찹쌀 외관 품질특성 구명)

  • Jeong, Eung-Gi;Lee, Choon-Ki;Choi, Yoon-Hee;Kim, Jung-Tae;Kim, Seok;Son, Jong-Rok
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.53 no.1
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    • pp.58-63
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    • 2008
  • Variation of chalkiness expression in milled waxy rice with the moisture contents of grains was investigated using instrument and naked eye evaluation methods. To find out any effects of varieties and harvesting times on the chalkiness development, rice grains of seven waxy varieties harvested at early, optimal and late times were tested after being sun-dried to have three different moisture contents of about $13.0{\sim}14.5%$, $14.5{\sim}16.0%$ and above 16.0%. The moisture contents of rice grains were distributed in the ranges of about 13.0% to 17.5% with the drying intensity right after harvesting. Although there were some genetical variations in whiteness and degree of transparency of milled rice grains among varieties at the same condition, chalkiness was most significantly affected by the changes of moisture content in all waxy varieties and harvesting times. At the moisture content less than 13.5%, all varieties exhibited waxy unique chalkiness, and at the moisture ranges between 13.5% and 14.0% the chalkiness was more or less affected by harvesting time and varieties. At the moisture content ranges between 14.0% and 16.0%, chalkiness gradually disappeared as with the increase of moisture content. However the degrees of chalkiness loses were strongly depended on individual kernels by showing as if the number of non-waxy rice kernels would be increasing in waxy rice grains with the moisture content increase. At the moisture content above about 16.0%, all waxy kernels lost their unique chalkiness, and showed non-waxy rice appearance.

The Effect of Antecedent Moisture Conditions on the Contributions of Runoff Components to Stormflow in the Coniferous Forest Catchment

  • Choi, Hyung-Tae;Kim, Kyong-Ha;Lee, Choong-Hwa
    • Journal of Korean Society of Forest Science
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    • v.99 no.5
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    • pp.755-761
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    • 2010
  • This study analyzed water quality data from a coniferous forest catchment in order to quantify the contributions of runoff components to stormflow, and to understand the effects of antecedent moisture conditions within catchment on the contributions of runoff components. Hydrograph separation by the twocomponent mixing model analysis was used to partition stormflow discharge into pre-event and event components for total 10 events in 2005 and 2008. To simplify the analysis, this study used single geochemical tracer with Na+. The result shows that the average contributions of event water and pre-event water were 34.8% and 65.2% of total stormflow of all 10 events, respectively. The event water contributions for each event varied from 18.8% to 47.9%. As the results of correlation analysis between event water contributions versus some storm event characteristics, 10 day antecedent rainfall and 1 day antecedent streamflow are significantly correlated with event water contributions. These results can provide insight which will contribute to understand the importance of antecedent moisture conditions in the generation of event water, and be used basic information to stormflow generation process in forest catchment.

Milling and Rice Flour Properties of Tempering Condition on Moisture Content of Rice (쌀의 수분함량별 Tempering에 따른 제분 및 쌀가루의 특성)

  • 김형열;이병영;유효숙;함승시
    • Food Science and Preservation
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    • v.6 no.1
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    • pp.76-80
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    • 1999
  • Power consumption, mesh size, moisture content, color difference, amylogram of rice flour milled with the water soaked rice were compared with that of rice using dry pin mill process. The rice was soaked in 23, 24, 25, 26% of water for 10hr, independently. The more rice had moisture content, the less power consumption was needed. Power consumption to mill the rice soaked in 25% of water was less than that of dry rice by 6.8kW/100Kg. Moisture content of rice flour from the rice soaked with 25% of water was 2% higher than that of rice flour from the rice soaked with 23% of, water. Population of flour particle from the rice soaked with 24-25% of water was 45.7∼46.25 of 60 mesh, 9.7∼10.4% of 80∼100 mesh and 7.7∼8.1% of 100 mesh. Gelatinization temperature of rice flour from the rice soaked with 23% and 24∼25% of water was 65.70C and 64.50C, independently. Temperature of rice flour from the rice soaked with 23% 24∼25% of water sith minimum viscosity was 85.50C and 88.4∼88.70C, independently. Brightness and whiteness of the rice flour from the rice soaked with 24∼25% of water were 95.90∼95.95 and 905.82∼95.94, independently. Brightness and whiteness of the rice flour from the soaked rice were 1.2 and 1.7 higher than that of rice flour from the dry rice, independently.

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Numerical Study on the Discharge of Humidity in the Drum of a Washing Machine (세탁기 드럼 내부의 습기 방출 메커니즘에 대한 수치 연구)

  • Jung, Chung-Hyo;Sohn, Deok-Young;Na, Seon-Uk;Choi, Yun-Ho
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.1
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    • pp.54-61
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    • 2016
  • Washing machine manufacturers typically advise consumers to maintain the relative humidity in the drum less than 80% for three days after the termination of a washing cycle in order to prevent bacteria proliferation. A vent installed in the back of a washing machine is used to release moisture to satisfy this condition. Up to now, the design and installation of the vent have been based on experiments without understanding its roles and physical phenomena. In this study, various CFD results are presented in order to explain the physical mechanism of moisture release in a washing machine. Two methods of moisture release (diffusion and convection) were studied; diffusion was found to be the dominant process in removing moisture. Experiments were also performed to validate this behavior. In addition, this study will aid in the efficient design of vents to keep the relative humidity low inside the drum.