• 한국환경농학회지
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• 제22권1호
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• pp.70-73
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• 2003

Nitrate contamination in the aquatic systems is the primary indicator of poor agricultural management. The influence of sewage sludge application rates (0, 10, 25, 50 and 100 dry Mg/ha) on distribution of nitrate originating from the sewage sludge in soil profiles was investigated. Soil profile monitoring of nitrate was carried out with a Lakeland clay soil in 1997. Irrespectively of the sewage sludge application rates up to 50 dry Mg/ha, the concentration of $NO_3$-N at the 120 cm depth was below 10 mg/kg and the difference due to the amount of sewage sludge application was negligible at this depth. There was virtually no $NO_3$-N below 120 cm depth and this was confirmed by a deep sampling up to 300 cm depth. Most of the nitrate remained in the surface 60 cm of the soil. Below 120 cm depth nitrate concentration was very low because of the denitrification even at high sewage sludge rate of 100 dry Mg/ha. The $NO_3$-N concentrations in the soil fluctuated over the growing season due to plant uptake and denitrification. The risk of groundwater contamination by nitrate from sewage sludge application up to high rate of 100 dry Mg/ha was very low in a wheat grown clay soil with high water table ( < 3 m).

• 한국의류학회지
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• 제12권3호
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• pp.383-390
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• 1988

To investigate the soil-redeposition and color change on dry-cleaning, the white and, dyed, fabrics of cotton, silk, polyester and viscose rayon were put into ordinary commercial dry-cleaning machine with soiled cloths. The solvents used were hydrocarben, perchloroethylene and fluorocarbon. From the result, we obtained the following conclusions by examining soil-redeposition, color difference of fabrics and tenacity of cotton fabric. 1. In case of white fabrics, as a whole, perchloroethylene shows the lowest soil redeposition. When distillation process is adopted, the rate of soil redeposition is lowered. with hydrocarbon sdvent. The order of soil redeposition rate of fibers are following; cotton> viscose rayon> silk> polyester. 2. In case of dyed fabrics, the color difference between soil redeposited fabrics and originals ($\delta\;E_1$) is similar with white fabrics in pattern, and the order is cotton, viscose rayon, silk and polyester. The color difference between fabrics, treated by pure solvents and originals ($\delta\;E_2$ ) is also validated as a little. It seems to be due to the bleeding of dyestuffs from fabrics. 3. There is a little change of tenacity of cotton fabrics by dry-cleaning with perchloroethylene solvent. It is supposed that the damage is more influenced the repetitive mechanical action during dry-cleaning than by acidity of the solvent having the acid value of 0,14.

• 한국염색가공학회지
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• 제20권3호
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• pp.18-24
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• 2008

The purpose of this study is to develop the dyeing method with dry leaves of indigo plant. Coloring matter was extracted from dry leaves of indigo plant with hot sodium hydroxide solution. The extract was reduced with sodium dithionite, and it was used for dyeing cotton fabrics under various conditions. UV-visible absorption spectra of extract, reduction rate of extracts by reducing agent, and the surface color of dyed cotton, lightfastness were examined. For the initial 20 minutes, the absorbance of indigo solution rapidly decreased. However, several hours later, the decreasing rate retarded. By repeating the dyeing process, the shade looked deeper and deeper. At $30-40^{\circ}C$, the value of K/S reached the highest point. The concentration of indigo solution in dye bath seemed to playa critical role for the reaction of the reducing agent. It was observed that the surface color of cotton fabrics was getting bluish and its degree of value and chroma seemed slightly decreased as the K/S value was increasing. The lightfastness was clearly enhanced by increasing the K/S value.

• 한국주조공학회지
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• 제2권1호
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• pp.2-11
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• 1982

In order to investigate the relationship between the thermal characteristics of the various molds as green sand mold, dry sand mold, $CO_2$ mold and shell mold, and the solidification characteristics of molten metal, the thermal analysis of rarious molds and melt were performed. The structure of Al-Castings was a/so observed. Results obtained in this experiment were as follows : 1) The heating rate of the molds was increased in the order of green sand mold, $CO_2$ mold, dry sand mold and shell mold, On the other hand the solidification time of the melts was shortened in the order of dry sand mold castings, $CO_2$ mold castings, green sand mold castings and shell mold castings. 2) The arrest temperature period in the heating curve of the green sand mold was resulted from the eraporation of moisture contained in mold, which was transfered to the outer side of the mold. 3) The temperature fluctuation of the melt in the shell mold was considered to be resulted from the combution heat of resin contained in the mold. 4) The amounts of heat absorption of the molds were increased in the order of dry sand mold, $CO_2$ mold, green sand mold and shell mold. 5) The higher the solidification rate was, the longer was its shrinkage pipe and the finer its grain size.

• 설비공학논문집
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• 제12권6호
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• pp.550-560
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• 2000

In order to minimize compression power and analyze the cause of exergy loss for a dry ice production cycle with 3-stage compression, the variation of compression power was investigated and the exergy analysis was peformed for the cycle. In this cycle, $CO_2$, is used both as a refrigerant and as a raw material for dry ice. The behavior of compression power and irreversibility in the cycle were examined as a function of intermediate pressure. From this result, the conditions for the minimum compression power were obtained in terms of the first stage or the third stage pressure. In addition, the irreversibilities for the cycle were investigated with respect to the efficiency of compressor. Result shows that the optimum pressure is not consistent with the conventional pressure obtained from the equal-pressure-ratio assumption. This is mainly due to the change in mass flow rate of the intermediate stage compressor by the flash gas evaporation from the flash drums. Most important is that the present exergy analysis enabled us to find bad performance components for the cycle and informed us of methods to improve the cycle performance.

• 한국정밀공학회지
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• 제27권1호
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• pp.119-124
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• 2010

This paper addresses the design and fabrication of desktop die-sinking dry electrical discharge machining (EDM) system and its experimental performance analysis. The developed desktop dry EDM machine has the horizontal configuration with the size of $300{\times}200{\times}260mm$. The experimental performance analysis is conducted to investigate the effects of EDM conditions and dielectric gas temperature on the surface roughness of EDMed slots and number of EDM sparks. The experimental results demonstrate that low feed rate and large electrode displacement are good for better surface roughness and more number of EDM sparks. In addition, low temperature of dielectric gas results in better surface roughness.

• 한국식생활문화학회지
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• 제18권5호
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• pp.437-442
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• 2003

This study was conducted to confirm the effect of drying method on quality of popped rice for making salyeotgangjung(popped rice lump with malt syrup) in process of drying gelatinized rice. The drying were performed at dry oven or convection oven, at $30^{\circ}C,\;50^{\circ}C\;and\;105^{\circ}C$, respectively. There were not significant differences in the hardness of popped rice among the drying methods. The dry at $30^{\circ}C$ constant in dry oven showed higher popping rate, good external surface, uniformed and well developed internal cell size. The dry at $30^{\circ}C$ in convection oven and $50^{\circ}C$ constant temperature in dry oven showed low expansion and poor external surface, respectively. In conclusion, the drying at $30^{\circ}C$ in non-convection oven had the highest quality of popped rice for salyeotgangjung.

• 한국생산제조학회지
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• 제9권2호
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• pp.36-44
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• 2000

In this paper drill shape and cutting conditions for environmentally conscious dry drilling of A319 Al-alloy are studied by experimental method. The experiment is planned with Taguchi's method that is based on the orthogonal array of design factors. The result is summarized as follows (1) Drill geometry optimization can increase the number of holes in dry drilling and also large helix angle and large point angle are desirable in dry drilling. (2) It is found that cutting conditions that is cutting speed and feed rate are closely related to the drill geometry(3) For dry drilling of Al-alloys drill shape and cutting conditions are selected and tested by experimental method. But it is found that the perfect dry drilling is difficult because of the machining characteristics of Al-alloys and so new machining method such as minimal lubricant application is required.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1486-1494
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• 2020

To evaluate transport-induced cladding embrittlement after interim-dry storage, ring compression tests were carried out at room temperature(RT) and 135 ℃. The ring compression test specimens were prepared by simulating the interim-dry storage conditions that include four peak cladding temperatures of 250, 300, 350 and 400 ℃, two tensile hoop stresses of 80 and 100 MPa, two hydrogen contents of 250 and 500 wt.ppm-H and a cooling rate of 0.3 ℃/min. Radial hydride fractions of the ring specimens vary depending on those interim-dry storage conditions. The RT compression tests generated lower offset strains than the 135 ℃ ones. In addition, the RT and 135 ℃ compression tests indicate that a higher peak cladding temperature, a higher tensile hoop stress and the lower hydrogen content generated a lower offset strain. Based on the embrittlement criterion of 2.0% offset strain, an allowable peak temperature during the interim-dry storage may be proposed to be less than 350 ℃ under the tensile hoop stress of 80 MPa at the terminal cool-down temperature of 135 ℃.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.315-318
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• 2001

In this paper recommends the development of automated silo dry & storage system. Most of existing round shaped iron silo arc used for only storage after dry and have many problems in storing. So We have developed an automated dry system which used the previously equipped silo and enables it to be used for storage after dry. The system features high frequency-resistance water sensor in Hopper scale that is in general use within the country its silo that is manufactured by the nerve DSP(TMS320C32) system water compensator and visualization that is finally realized with a personal computer.