• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.557-563
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• 2008

Recently, the amount of disposed construction materials like demolished concrete is growing fast and the shortage of natural concrete aggregate is becoming serious. Therefore, recycling of aggregate extracted from the demolished concrete is getting important and use of the recycled aggregate for concrete has been seriously considered. However, the use of the recycled aggregate even for low performance concrete is very limited because recycled aggregate which contains large amount of old mortar has very low quality. Therefore, removing the paste sticked to the recycled aggregate is very important in the manufacturing of high quality recycled aggregate. We have studied a series of research according to complex crushing method, which is removed the ingredient of cement paste from recycled fine aggregate using both the low speed wet abrasion crusher as mechanical process and the acid treatment as chemical processes. This paper is to analyze the quality of the recycled fine aggregate produced by those complex method and investigate optimum manufacturing condition for recycled fine aggregate by the design of experiments. The experimental parameters considered are water ratio, coase aggregate ratio, and abrasion time. As a result, data concerning the properties of recycled sand were obtained. It was found that high quality recycled fine aggregate could be to obtain at the condition of the fifteen minute of abrasion-crusher time and the over 1.0 of recycled coarse aggregate ratio.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1997.05a
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• pp.11-16
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• 1997

본 연구는 양액재배에서 영양진단에 기초한 배양액관리를 하기 위해 유효한 수단으로 이용되고 있는 신속하고 간편하며 정확한 즙액분석 방법(질산태질소의 정량방법, 인산정량방법, 즙액추출법, 추출비율, 마쇄시간 및 샘플채취 부위 등)들에 관한 비교검토를 하였다. 'Earl's Favorite 춘계 F$_1$호'를 1993년 1월 11일에 파종하여 본엽 3~4매의 묘를 스티로폼베드내 암면슬라브에 정식하여 비순환방식으로 재배했다. 즙액분석법은 결핍이나 과잉증상이 외관적으로 나타나기 전에 신속하고 간이한 즙액분석법에 의해 작물체의 영양상태를 진단하여 대응이 가능하다고 판단되었다. 즙액분석시 질산태질소의 분석에는 자외부흡광도법, 인산분석에는 바나드몰리브덴산법이 추천되었고, 추출비율은 1:4로, 엽병의 마쇄시간은 60초, 그리고 채취 부위는 일정부위로 하는 것이 바람직하다고 판단되었다. 그러나 샘플채취시간에 대해서는 채취시간에 따른 차이가 크기 때문에 앞으로 보다 상세한 검토가 요청되었다.

• Land and Housing Review
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• v.14 no.4
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• pp.121-129
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• 2023

In this study, we attempted to reduce CO₂ generated during manufacturing by replacing limestone (CaCO₃), a carbonate mineral used to produce cement clinker, with a decarbonated raw material to which CO₂ is not bound. The raw material for decarbonization was cement paste attached to waste concrete, among various industrial by-products. Waste concrete has cement paste adhered to the aggregate, which cannot be separated efficiently by general crushing and grinding methods. Peeling and grinding methods effectively remove only the cement paste without damaging the original aggregate. The abrasion time, steel ball type, and steel ball ratio were selected as effective factors for Abrasion. An optimal abrasion experiment was conducted to produce waste concrete fine powder containing decarbonated CaO as a cement clinker raw material through an experimental design method. The experiment revealed that the optimal conditions for producing waste concrete fine powder were an abrasion time of 7 minutes, a steel ball size for pulverization of 8 mm, and a steel ball ratio for pulverization of 0.6.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.310-316
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• 1997

This experiments comparisons were conducted to establish the effective sap analytical method including quantitative analysis of nitrate and phosphorous, sap extraction method, extraction rate, macerating time and sampling position. Earl's Favorite muskmelon was sown on February 11th, 1993 and transplanted to rockwool slab when three to fourth true leaf appeared. Non-circulating system was employed in this experiment. Sap testing using a sample provides an immediate analysis of nutritional status of the crop and potential problems can be recognized and corrective measures taken. Some methods were recommended UV-spectroscopy for the analysis of nitrate nitrogen, Vanad molybdenium acid method for phosphorous. Optimal extraction rate of sample to water was determined as one to four and the best result observed at 60seconds in macerating duration. Further trials would be requested about sampling time due to the difference according to the sampling time. Given sampling position was favorable for the sap analysis.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.822-829
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• 1997

When $Al_2(SO_4)_3$ as an accelerator was added to $\beta$-hemihydrate gypsum, the setting time, mobility and compressive strength properties of $\beta$-hemihydrate gypsum were examined with the adding of two types grounded gypsum crushed by ball mill. By 15wt% adding of 7% $Al_2(SO_4)_3$ dilute solution, the setting time of $\beta$-hemihydrate gypsum was sharply accelerated than that of non-added $\beta$-hemihydrate gypsum. When ground phospho gypsum(PG) and chemical gypsum(CG) were added to $\beta$-hemihydrate gypsum, the initial and final setting time of $\beta$-hemihydrate gypsum were accelerated markedly with the increasing of grinding time and added amount of ground phospho gypsum. Especially, this trend largely presented when ground phospho gypsum was added to $\beta$-hemihydrate gypsum. The compressive strength of $\beta$-hemihydrate gypsum added by ground phospho and chemical gypsum was largely increased at initial curing time such as 1, 3 days. Particularly, the compressive strength of $\beta$-hemihydrate gypsum added by ground phospho gypsum was increased by 15~20% than that of ground chemical gypsum.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.927-935
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• 2005

The objectives of this study were to investigate the soaking properties of the high-dietary fiber rice 'Goami 2'and to develop korean white Gruel prepared with Goami 2. With increasing soaking time at room temperature ($20^{\circ}C$), the water absorbing character of Goami 2 and Ilpum significantly increased during the first hour of soaking time, after which it remained constant. On the contrary, the hardness of Goami 2 and Ilpum significantly decreased with increasing soaking time until one hour, after which it remained constant. The properties of Korean white gruel were evaluated using two varieties of rice (Goami 2, Ilpum) and three blending times (10, 20 and 30 seconds respectively). The rice flour of Goami 2 for Korean white gruel showed a greater number of small particles (<20 $\mu$m) than that of Ilpum. Hunter a'and b'values of Korean white gruel prepared with Goami 2 were higher than that of Korean white gruel prepared with Ilpum. The consistency values on Bostwick consistometer of Korean white gruel prepared with Goami 2 were higher than those of Korean white gruel prepared with Ilpum. The texture of Korean white gruel was examined using a back extrusion rig. All of the rheological parameters of Korean white gruel prepared with Goami 2 were decreased with increasing blending time, while in llpum they were increased. In the sensory evaluation results, the overall acceptability of korean white gruel prepared with Goami 2 blended for 20sec showed the highest sensory scores and desirability.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.219-225
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• 2010

The solubility in water of granular pesticides is not equal because the difference of methods of producing a granular pesticide. This study was conducted to investigate fish acute toxicity of butachlor 5% GR, fipronil 0.4% GR by impregnation and carbosulfan 3% GR, diazinon 0.4% GR by coating, using carp (C. carpio), medaka (O. tatipes) and loach (M. anguillicaudatus). The test solution of each pesticide was prepared by direct addition of granular pesticide and add after grinding granular pesticide to powder in test water, We also investigated $LC_{50}$ and residual concentration until 96 hours. Test results were appeared that the treatment of powder was 1.2~4 time higher than granular and toxicity increased clearly according to elapsed time, And the residual amounts by time were detected much at early time in the powder treatment of butachlor GR and diazinon GR. Conclusively, fish acute toxicity and residual concentration in test solution appeared higher in the powder treatment than treat granular form directly in water. Also, 96 hours toxicity values were stable comparatively and the error is less than 48 hours.

• Culinary science and hospitality research
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• v.14 no.1
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• pp.144-151
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• 2008

This study investigated the changes in the contents of allicin and diallyl disulfide and in the alliinase activity during the vacuum freeze drying of onion samples treated as the whole, sliced and crushed forms. The contents of allicin and diallyl disulfide in raw onions were 26.40ppm and 2.78ppm respectively. The contents of allicin and diallyl disulfide of onion samples treated as the whole, sliced and crushed forms increased with the progress of vacuum freeze drying. The degree of increase was different in each onion sample form prepared by vacuum freeze drying(p<0.05). The specific activity of alliinase in raw onions was 7.536 units/mg protein. The activity in onion samples treated as the whole, sliced and crushed forms decreased with the progress of vacuum freeze drying. The activity in the whole onion prepared by the vacuum freeze drying for 8 hrs reduced to 5.516 units/mg protein with 73.2% remaining and to 3.304 units/mg protein with 43.8% remaining for 36 hrs. The activity in the sliced onion prepared by the vacuum freeze drying for 36 hrs reduced to 2.366 units/mg protein with 31.4% remaining and the activity in the crushed onion prepared by the vacuum freeze drying for 36 hrs reduced to 2.232 units/mg protein with 29.6% remaining. The alliinase in onion sample treated as the whole form showed the highest remaining activity during the vacuum freeze drying.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1319-1321
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• 1997

The effect of cooking peanut kernels before grinding on the hexanal content of peanut milk was investigated. Hexanal which is thought to be one of the major compounds contributing to the beany flavor of peanut milk, was quantified using a simplified headspace gas chromatographic method. Four cooking times (0, 10, 20 and 30 min) were evaluated. The concentration of hexanal in peanut milk was one-third by cooking peanut kernels for 10 min or longer. Protein content of peanut milk gradually decreased by heat treatments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.136-140
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• 1986

The change of cell counts of Vibrio parahaemolyticus in fish muscle by the storage time and temperature was examined to get basic informations for precautionary steps against food poisoning of slices of raw fish (sashimi). There fore, we inoculated fish homogenate of oceanic bonito (Katsuwonus pelamis), yellow tail (Seriola quinqueradiata) with Kanagawa positive Vibrio parahaemolyticus and stored it at $30^{\circ}C,\;18^{\circ}C,\;4^{\circ}C\;and\;-20^{\circ}C$ for 24 hours. The number of the Vibrio parahaemolyticus upon fish homogenate stored at $30^{\circ}C\;and\;18^{\circ}C$ decreased for the first two hours and increased thereafter. When the fish homogenates inoculated with Vibrio parahaemolyticus at about $10^3$ per gram were stored at $18^{\circ}C\;and\;30^{\circ}C$ for 10 hours, the cell numbers increased about 10 times and 1,000 times initial cell numbers, respectively. The survival rate of Vibrio parahaemolyticus was about $20\%$, when the inoculated fish homogenates were stored at $-20^{\circ}C$ for 24 hours. Vibrio parahaemolyticus inoculated in fish homogenates was decreased by about $10\%$ of initial cell numbers by the storage at $4^{\circ}C$ for 4 hours and it was decreased by about $50\%$ after 24 hours storage of the samples at the same temperature. The decreasing rate of inoculated Vibrio parahaemolyticus in fresh fish muscle homogenate was higher than that in frozen fish muscle homogenate during the storage time at a refrigerator.