• Journal of Biosystems Engineering
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• 제34권6호
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• pp.439-445
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• 2009

This study was performed to investigate the optimum abrasive and friction milling ratio. This was accomplished by determining changes in the quality, such as whiteness, moisture content, broken kernel, unstripped embryo rate, and surface characteristics or milling difference, during an abrasive and friction based milling process. When only abrasive was milled, the increase of whiteness was fast in the first milling, whereas the increasing rate of whiteness was small in the latter milling. The decreasing rate of moisture content and broken kernel increased as the friction milling ratio was increased. Combining with the friction milling was considered a suitable method because the unstripped embryo rate was high only when abrasive milling was used. In the case of a high abrasive milling ratio, a significant milling difference was observed in the initial milling. This indicated that the milling difference was not completely eliminated despite using friction milling in the latter milling. Consequently, it was necessary to minimize the milling difference in the initial milling. When milling quality was synthetically considered, the abrasive milling ratio was varied from 20~50%. When the abrasive milling ratio was greater than 40%, the external quality of the rice milled deteriorated since holes and defects generated on the surface in the initial milling were not removed. Due to this deterioration in surface characteristics, an abrasive milling ratio of 30% was identified as a suitable level.

• Journal of Biosystems Engineering
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• 제39권4호
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• pp.336-344
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• 2014

Purpose: In this study, the effect of milling on paddy rice stored at low temperature, the changes in grain temperature of bulk storage bags exposed at room temperature, the post-milling water content of paddy rice, the whiteness of rice, and the rate of pest incidence were investigated and data were analyzed. Methods: Changes in temperature inside the bulk storage bags kept at low temperature and grain temperature after exposure to room temperature were measured. Experiments were conducted for identifying the reasons of post-milling quality changes in paddy rice stored at low temperature. Results: It was determined that a short-term increase of water content in paddy rice was directly related to surface condensation, and that rice should be milled at least 72 h after removal from low-temperature storage, in order to completely eliminate surface condensation of paddy rice kept in bulk storage bags. It was observed that post-milling quality of rice changed, but water content was maintained at high levels for more than 18 d in rice that was milled when condensation occurred, regardless of paper or vinyl packaging. Rice whiteness rapidly decreased in rice that was milled when condensation occurred, regardless of packaging, while rice that was milled 72 h or more after removal from low temperature storage did not show any significant changes in whiteness. No pest incidence was observed up to 12 d after removal from low temperature storage, regardless of packaging. Starting at 18 d, after removal from low temperature storage, rice that was milled when condensation occurred, was affected by pests, while 24 d after removal from low temperature storage, all portions of rice were affected by pests. Conclusions: Our results suggest that changes in post-milling quality of rice could be significantly reduced by exposing paddy rice to room temperature for at least 72 h before milling, in order to allow the increase of grain temperature and prevent surface condensation.

• 자원리싸이클링
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• 제20권6호
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• pp.71-77
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• 2011

용융클링커 제조용 혼합원료 중의 하나로 고로슬래그를 사용하였다. 고로슬래그를 사용한 혼합원료는 용융클링커 제조를 위해 1620에서 용융하였다. 냉각된 클링커는 XRD 패턴으로 클링커 광물의 생성여부를, 색도분석기로 색도를 분석하였다. 용융클링커는 XRD 분석을 통해 OPC 광물과 동등의 클링커 광물을 포함하고 있다는 것을 확인할 수 있었다. 용융시멘트는 OPC보다 백색도가 높아, 색상이 OPC보다 옅게 관찰되었다. 용융시멘트의 LSF 및 SM이 높아짐에 따라 백색도는 낮아졌다. 또한 슬래그를 용융시켜 제조한 시멘트 클링커는 고로 슬래그시멘트보다 백색도가 높았다.

• 대한치과기공학회지
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• 제36권1호
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• pp.9-15
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• 2014

Purpose: Generally dental technicians clinically decide the sintering temperature of zirconia artificial teeth to match the color of the teeth. However, the sintering temperature influence the microstructure and mechanical strength of ceramic body. In this study, to evaluate the free choice of sintering temperature which leads to color the problems in zirconia false teeth, the variation of microstructure, mechanical strength, and colortone of zirconia ceramics according to the change of sintering temperature was investigated. Methods: Bar type specimens were prepared from commercial zirconia blocks by cutting and polishing into $0.8cm(L){\times}1.0cm(W){\times}4.8cm(H)$. Specimens were fired from 1,400 to $1,700^{\circ}C$ at $50^{\circ}C$ intervals and held for 1hour at highest temperature. Apparent porosity, water absorption, firing shrinkage, bulk density, bend strength, whiteness were tested. Microstructures were observed by SEM. Results: When fired above $1450^{\circ}C$, all specimens showed 0% apparent porosity and water absorption, 20% firing shrinkage, and $6.1g/cm^3$ bulk density regardless of firing temperatures. SEM photomicrographs showed grain growth of zirconia occurred above $1,600^{\circ}C$. Whiteness was also largely changed above this temperature. Maximum bend strength of 1,05MPa was obtained at $1,550^{\circ}C$. Bend strength lowered slightly above this temperature and showed $950{\ss}\acute{A}$ at $1,700^{\circ}C$. Conclusion: In order to fit the colortone of zirconia artificial teeth, arbitrary choice of firing temperature higher than $1,500^{\circ}C$, up to $1,700^{\circ}C$ did not influence the mechanical strength.

• 청정기술
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• 제10권4호
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• pp.195-201
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• 2004

기능성 고분자와 셀룰라아제가 화학적으로 결합된 수식 셀룰라아제를 이용하여 폐신문용지(Old Newsprint, ONP)의 탈묵공정에 적용하였다. 수식 셀룰라아제 중의 셀룰라아제는 섬유의 피브릴화(fibrillation)를 촉진시켜 잉크입자의 박리를 향상시켰으며, 수식 셀룰라아제 중의 수식 고분자가 탈묵공정에서 분리된 잉크입자를 부상제거하는 새로운 탈묵 공정이 완성되었다. 수식 셀룰라아제를 이용한 공정은 극소량의 수식 셀룰라아제의 사용으로 인장강도, 백감도(brightness), 백색도(whiteness)를 포함한 물리적 성질을 기존 탈묵공정에서의 그것보다 향상시켰다. 잉크와 섬유의 결합은 저장 기간이 증가함에 따라 더욱 강해지고, 기존의 방법으로는 잉크입자 제거가 어려운 반면, 수식 셀룰라아제를 이용한 공정은 잉크입자 제거에 매우 탁월한 효과를 나타내었고, 약 1년간의 보존 기간을 가진 폐신문용지의 탈묵 효과를 41% 향상시켰다. 또한 이 공정은 황변현상을 제거했으며, 섬유의 피브릴화를 촉진시켜 재생지의 물리적 성질인 인장강도와 내부결합도를 향상시켰다.

• 한국작물학회지
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• 제40권4호
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• pp.512-517
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• 1995

질소의 추비가 품질특성에 미치는 영향을 조사하기 위하여 1993년 일본의 동북농업시험장의 화산회토인 포장에서 미유기 보리를 공시품종으로 하여 재생기, 유효분벽기 그리고 출수기에 유안을 질소 성분량으로 2 또는 4kg을 추비하였다. 도종율 백도 조단백질 등을 조사한 결과를 요약하면 다음과 같다. 1. 55% 도종기간은 2kg을 추비하면 길어지나 추비 시기간에는 차이가 없었다. 백도, 경도 그리고 도종율도 추비에 의한 차이는 없었다. 2. 원맥의 조단백질함량은 추비에 의하여 증가하였으나 시기간에는 차이가 없었다. 3. 원맥의 조단백질함량과 55% 도종기간과는 정의 상관관계가 있었으나 8분 도정림의 백도와는 상관이 없었다. 4. 8분 도종율 및 8분도정립의 백도와는 부의 상관관계가 있었고, 8분 도종율과 55% 도종시간과는 정의 상관관계가 있었다. 백도 형질간에는 상관관계가 없었다. 5. 주사형 전자현미경에 의한 미세구조관찰에서 추비처리에 의한 Protein matrix의 차이는 없었다.

• 한국의류학회지
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• 제18권4호
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• pp.549-559
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• 1994

The purpose of this study was to study accumlated residual soils which may be one of the causes for yellowing of worn cloths. Wear and wash tests of white cotton undershirts were repeated at 30 households sellected at random over a period of 60 days. Laundry conditions were similar to home laundry habits in a fact-finding survey, using a powdery heavy duty detergent containing no enzymes or enzymes. The subjects in this study were survey of laundry actual condition, the undershirts from prior to and after the final washing was measured residual soils, $L^*a^*b^*$ value and mellowness index of CIE system. D3ta were analysed by simple correlation analysis of wear and wash cycle, residual soils, whiteness The results obtained were summarized as follows: 1. Using pattern of washing machine, Presoaking was no singinificant differnece in general characteristics of survey respondent. Laundry frequency was significant difference in income level, occupation of housewives whether or not. Use of cold and hot water was significant difference in residence shape. 2. The analyzed consequences of recognition and actual behavior in connection with laundry were found variables each other to have independence or not. 3. Amount of residual sebum soils is using non-enzyme detergent were much more than in using enzyme detergent, increased linearly with increase of the number of wear and wash cycles. 4. Residual protein soils with increase of the number wear and wash cycles less than in laundering more easy than sebum soils. Since accumulated residual sebum soils were much more than residual protein soils. 5. Increase of residual soils was raised mellowness index and diminshed whiteness. yellowness index of residual sebum soils was higher than protein soils. If increase of whiteness will be incresed, amount of residual sebum soils will be decreased sebum soils. Because amount of residual sebum soils much more than protein soils, yellowness index of residual sebum soils was more higher than that of protein soils.

• 한국수산과학회지
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• 제28권3호
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• pp.301-308
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• 1995

소비자의 수용도에 중점을 둔 저염젓갈의 품질 기준을 설정하기 위하여 출하 직전의 시판 젓갈을 반제품과 완제품의 형태로 $30^{\circ}C:$에 저장하여 품질 저하를 시키면서 관능검사와 이에 따른 이화학적 검사를 병행하였다. 명란젓갈의 경우 Brix가 반제품 $47.6\%$ 이상, 완제품 $41.2\%$ 이상이면 합격품으로 판정되었으며 제조회사 별로 절대값의 차이는 있었지만 백색도도 소비자의 수용도가 떨어질 수록 증가하는 경향을 보였다. 반면, 오징어 젓갈은 원료의 특성상 백색도는 기준으로 설정하기 어려웠으나 Brix는 제조회사 별로 기준을 설정하면 소비자 수용도와 상관관계를 설정할 수 있을 것으로 추정되며 pH도 같은 경향을 나타내었다. 결론적으로 저염젓갈의 품질 평가는 관능적 평가와 이론학적 검사를 병행하는 것이 타당하며 이화학적 검사 항목으로 Brix, 백색도, pH 및 hypoxanthine 등을 들 수 있는데 이 중에서 Brix가 가장 좋은 기준이 되며 hypoxanthine은 제품에 따라 차이가 많아 좋은 기준이 될 수 없었으나 오징어젓갈의 경우는 제조 방법이 같을 때 유의할 만한 평가 항목이 될 것으로 판단되었다.

• 한국의류학회지
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• 제33권2호
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• pp.213-221
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• 2009

This study provides the optimum papain treatment method and its effect on wool/polyester blend fabrics. The enzymatic treatment condition is optimized depending on its pH level, temperature, concentration of enzyme, treatment time and concentration of activators. The characteristics of samples treated with the papain are measured using weight loss, tensile strength, whiteness, WCA, dyeing property and surface micrographs. The results are described as follows: According to measuring weight loss, tensile strength and whiteness, a pH level of 7.5, $70^{\circ}C$, 10% papain(o.w.f.) and 60minutes of treatment time are optimized for papain treatment. L-cysteine and sodium sulfite are able to activate the papain. The optimum concentrations of them are 10mM and 50mM respectively. The WCA of fabrics is decreased since papain treatment makes wool/polyester blend fabrics more hydrophilic. Scouring with papain treatment improves whiteness and dyeing property of fabrics. The dyeing property of papain-treated fabrics is enhanced simply by a single step dyeing process using a basic dye. The surface of wool treated with papain in the presence of L-cysteine shows to be descaled. The surface of wool fibers in the presence of sodium sulfite, however, shows it is hydrolyzed evenly instead of being descaled. The surface of papain treated polyester fibers shows cracks and voids.

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.469-474
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• 2001

Milling the rice with low moisture requires more energy, produces more cracked rice, and results in reducing taste of cooked rice. Accordingly, it is necessary to add moisture to the rice with low moisture to obtain optimum moisture level for milling and taste of rice. This study was performed to evaluate the influence of initial moisture content and absorption rate on rice crack, milling energy and whiteness of milled rice and to obtain the information for design of rewetting system mounted on stirring device in grain bin. The tests were conducted for the four levels of initial moisture content in the range of 11.4 to 14.5%(w.b.) and six levels of absorption rate in the range of 0.04 to 1.0%, w.b./hr. In the case of lower moisture content below 12%(w.b.), crack ratios of brown rice were remarkably high regardless of initial moisture contents. Therefore, it was found that rough rice below 12%(w.b.) in initial moisture content could not rewetted by spraying water without crack generation of low level. Absorption rate must be below 0.3%, w.b./hr to maintain crack ratio increase of less than 1% regardless of initial moisture contents. In the case of allowable crack ratio increase of 2% and 5%, it was found that the maximum absorprion rate was respectively 0.6%, w.b./hr and 1.0%, w.b./hr in the initial moisture content of above 13.5%(w.b.). Rewetting the rough rice in moisture content of 11.4 to 14.5%(w.b.) to 14.3 to 16.9%(w.b.) decreased milling energy consumption by 15.9 to 22.3%. The effect of energy saving was higher in the samples of higher initial moisture content. Whiteness of milled rice was decreased by 0.5 to 1.5.