• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.260-262
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• 2002

The scope of applications industrial or household manufactures, is on the increase. In this study, it applies a principle of induction heating to food dryness for preservation of food. And it applies indirect heating process using overheating steam, which analyzes thermal characteristic of heating apparatus depending on its construction. It was verified that application of proposed process was appropriate by drying test of food.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.146-147
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• 2006

In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Rotary dryer is a good apparatus to treat them. The rotary dryer is the way that is to make substance transmission and heat using hot air between sludge particle and heated gas. In this paper, a numerical analysis was performed for the structural analysis of the 3-pass rotary dryer through the finite elemeny method and an experiment was done for the structural stability. And reasonable relation was found between analysis and experiment.

• Food Engineering Progress
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• v.13 no.4
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• pp.308-313
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• 2009

This study was conducted to design and fabricate a heat pump that can produce some weather conditions similar to those of the dry season of the rough rice in Korea, and to investigate basic performances of the apparatus. During the drying test, the amount of energy consumption and drying characteristics were measured at four different temperature levels ranging between 20$^{\circ}C$ and 50${^{\circ}C}$. In the psychrometric chart, the freezing capacity and refrigerant circulation ratio of the heat pump were 173 kJ/kg and 49.6 kg/hr, respectively. Therefore, coefficient of performance was 5.5, which was superior to that of refrigerant R-22 (4.0) in standard refrigeration cycle. In addition, the time to reach target drying temperature (30${^{\circ}C}$) and relative humidity (40%) were 6 minutes and 7 minutes, respectively. Temperature differences between the drying temperature and the rice were 1.5${^{\circ}C}$ and 8.5${^{\circ}C}$ at the drying temperatures of 21.9${^{\circ}C}$ and 48.7${^{\circ}C}$, respectively. This result demonstrated that the increased temperature of the rice in the drying section decreased sufficiently in the tempering section. At the drying temperatures of 21.9, 30.7 38.8, and 48.7${^{\circ}C}$, drying rates were 0.29, 0.61, 0.85, and 1.26%/hr, respectively, which were similar to those of commercial dryer. In addition, the amounts of energy consumption were 325, 667, 692, and 776 kJ/kg, respectively. These results showed that this dryer saved up to 86% of energy consumption compared with the commercial dryer, which uses 4,000-5,000 kJ/kg of fossil fuel.

• The Journal of Engineering Geology
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• v.28 no.1
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• pp.25-34
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• 2018

The physical properties and unsaturated characteristics of acid sulfate soils were investigated and analyzed. As the results of measuring physical properties of the acid sulfate soils obtained around the Ilkwang mine area, the dry unit weight is $1.246t/m^3$ and this soil is classified into the silty sand (SM) by USCS. Soil Water Characteristics Curves (SWCC) of the drying and wetting paths were measured by the automated SWCC apparatus. Also, Hydraulic Conductivity Functions (HCF) of the drying and wetting paths were estimated by the van Geunchten (1980) model which is the most well-known parameter estimation method. The hydraulic conductivity of acid sulfate soils in the dry path was continuously decreased with increasing the matric suction. However, the hydraulic conductivity in the wetting path was decreased relatively small with increasing matric suction and decreased suddenly just before water entry value of matric suction. Meanwhile, the hysteresis phenomenon was occurred in SWCCs and HCFs during the drying and wetting paths.

• Journal of Powder Materials
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• v.19 no.6
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• pp.398-404
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• 2012

This paper describes the spherical ammonium diuranate gel particles which are the intermediated material of the $UO_2$ microsphere for an VHTR(very high temperature reactor) nuclear fuel. The characteristics of the intermediate-ADU gel particles prepared by AWD(ageing, washing, and drying) and FB(fluidized-bed) apparatus were examined and compared in a sol-gel fabrication process. The electrical conductivity of washing filtrate from the FB treating and the surface area of dried-ADU gel particles were higher than those of AWD treating. Also, an internal pore volume in dried-ADU gel particles showed a more decrease in AWD treatment than FB treatment because of decomposition of PVA affected by the washing time. However, the internal microstructures of ADU gel particles were similar regardless of the process variation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.614-619
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• 2010

We proposed perfect recycling method of sea waste. The sea waste(rotten sea fish, rotten shell fish etc.) have bad smell and generate waste water, so these waste materials must be treated quickly. If we use speedy dryer, these sea waste can be changed to useful feed and liquid composts. Also this study relates to a method for drying a variety of untreated waste materials in a hermetically sealed state, and subsequently carbonizing the dried waste materials under a reduced pressure, thereby achieving a more stable and economical treatment for the waste materials, and an apparatus for performing the method. This effects of preventing generation of contaminants and environmental pollution while reducing fuel costs, and a carbide, obtained via the drying and carbonization of the waste material, are available into feed for poultry. The condensate water can be used to deodorants.

• Journal of the Korean Geotechnical Society
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• v.28 no.3
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• pp.55-66
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• 2012

To investigate the hysteresis of the suction stress in unsaturated weathered mudstone soils (CL), matric suction and volumetric water content were measured in both drying and wetting processes using Automated Soil-Water Characteristics Curve Apparatus. The drying and wetting processes in unsaturated soils were reproduced in the test; the drying process means to load matric suction to spill pore water from the soils, and the wetting process means to unload matric suction to inject pore water into the soils. Based on the measured result, Soil Water Characteristic Curve(SWCC)s were estimated by van Genuchten model (1980). SWCCs have nonlinear relationship between effective degree of saturation and matric suction. The hysteresis in SWCCs between drying and wetting processes occurred. As a result of estimating Suction Stress Characteristic Curve(SSCC) using Lu and Likos model (2006), the suction stress rapidly increased in the low level of matric suction and then increased slightly. Also, the hysteresis in SSCCs between drying and wetting processes occurred. In order to design geo-structures and check its stability considering unsaturated soil mechanics, therefore, it is more reasonable that the SSCC of drying process should be applied in the condition of rainfall infiltration and the SSCC of wetting process in the condition of evaporation or drainage.

• Journal of the Korean Geosynthetics Society
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• v.10 no.3
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• pp.25-32
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• 2011

The matric suction and volumetric water content of dredging soils obtained from Saemangeum area were measured by the automated Soil-Water Characteristic Curve (SWCC) apparatus under both drying and wetting conditions. Based on the test result, SWCCs of the dredging soils were estimated by the van Genuchten(1980) model. The matric suction of drying process is larger than that of wetting process at a same effective degree of saturation. The suction stresses for various matirc suctions were estimated using Lu and Likos(2006) model and the Suction Stress Characteristic Curves (SSCC) were predicted using the independent parameter of SWCC. The suction stress of drying path was increased and decreased, while the suction stress of wetting path was continuously decreased with increasing the effective degree. Also, the suction stress of drying path is larger than that of wetting path at a same effective degree of saturation. The Hydraulic Conductivity Function(HCF) was also predicted by the van Genuchten(1980) model. The hydraulic conductivity was increased with increasing the volumetric water content. The hydraulic conductivity of drying path is larger than that of wetting path at a same matric suction. According to the results of SWCCs and SSCCs, the hysteresis phenomenon of suction stress or matric suction during both drying and wetting paths was occurred. The main reason of hysteresis phenomenon is a ink bottle effect of water among soil particles.

• Water for future
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• v.28 no.4
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• pp.215-222
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• 1995

The water retention function which has the hysteresis phenomena is required to analyze the Richards equation which is a governing equation of the unsaturated flow, and its hysteresis phenomena has influence upon the characteristics of the unsaturated flow. The accuracy of the published hysteresis models is compared by using experimental data of the water retention function. The apparatus to experiment the hysteresis phenomena on the soil is developed, and experimental data for the main wetting process and the main drying process of the water retention function are obtained. The parameters of the van Genuchten equation are calibrated by using experimentally obtained data. As a result of the comparison of the selected hysteresis models which simulate the main drying curve from the main wetting curve, the Model I-1(Mualem) overestimates and the Model II-1(Mualem) underestimates but the Model III-2(Park and Sonu) similarly estimates the experimental data of the main drying curve.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1473-1479
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• 2009

This study have been carried out as a part of R&D project to develop a low cost high efficiency combined grain drying & storage system. The design of sweeping auger must meet the various conditions : capacity and dimensions of silo, discharging capacity of auger, operation conditions of auger such as revolution and rotation and density of grains and even the first-in & first-out of grains in the system. Through the experimental observations with the apparatus which enables the direct observation of discharging behavior of grains, the limitations of the performance of existing straight type auger was observed. Generalized mathematical model for the profile of new variable section sweeping auger was obtained, which ensures the uniform descending of grains and also meets various operating conditions. The experimental results with a prototype sweeping auger showed that the mathematical model for the variable section sweeping auger was quitely correct.