• 한국유체기계학회 논문집
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• 제5권1호
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• pp.20-26
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• 2002

This study reports the analysis of the pressure drop characteristics for the air-particle flow in powder transport piping system. The pressure drop characteristics of air-particle flow in piping system is not well understood due to the complexity of particles motion mechanism. Particles or powders suspended in air flow cause the increase of the pressure drop and affect directly the transportation efficiency. In this study, the pressure drop in powder transport piping system with straight and curved pipes is analyzed for the interactions of air flow and particle motion. The total pressure drop increases with increasing of the pipe length, the mixture ratio, and the friction factor of particles due to the increasing friction loss by air and particles in a coal piping system. For the coal powders of $74{\mu}m$ size and powder-to-air mass mixture ratio of 0.667, the total pressure drop by the consideration of powders and air flow is $30\%$ higher than that of air flow only.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.172-179
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• 1996

Recently, the broken concrete lumps resulting from the demolition of concrete structures are creshed for reuse as aggregates(i.e. recycled fine and gravel). And also, in the processing of crusing, the recycled powder of an equivalent of between 20% to 30% by wt.% of the broken concrete lumps is generated. The extensive research of recycled concrete aggregates has been carried out in various parts of the world. But less reseatch on the reuse of recycled concrete powder has been carried out. It is the purpose of this report that the study on the quality evaluation of recycled aggregates for recycled concrete. In specially, this report deals with the properties such as flow, compressive strength, bending strength, drying shrinkage and wight loss rate of mortars replaced standard fine aggregate with recycled powders at the rate of 3, 7, 15, 20 and 30 wt.%. Since the characteristics of recycled mortars with the recycled powders were comparable to those of the normal mortar without the recycled powders as described above, its concretes could be found extensive application in such field as concrete products.

• 한국식품조리과학회지
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• 제27권4호
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• pp.1-16
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• 2011

The purpose of this study was to investigate the physicochemical and sensory properties of various breads prepared with purple-fleshed sweet potatoes and their powders. As the amount of purple-fleshed sweet potato and its powder increased, pH of the dough and bread, volume, dough yield, baking loss rate, and fermentation power of the dough decreased, whereas acidity of the bread increased. The lightness and yellowness of the breads decreased significantly, but redness increased with increasing content of purple-fleshed sweet potato and its powder. The textural properties, such as hardness, chewiness, springiness, and brittleness were significantly higher in groups with added purple-fleshed sweet potato and its powder compared to those in the control. The anthocyanin content and DPPH radical scavenging of dough and bread were higher in groups with purple-fleshed sweet potato and its powder than those in the control group. The groups with 5% and 10% purple-fleshed sweet potatoes and their powders had significantly higher scores for overall acceptability as compared to the control group.

• Food Science and Biotechnology
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• 제16권2호
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• pp.187-192
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• 2007

The objectives of this study were to examine changes in the color and antioxidant compounds of paprika powder under various conditions, as well as to establish the suitable conditions for drying and storage. Paprika was dried using the following methods: freeze-drying, vacuum drying, far infrared-ray drying, and hot-air drying. Measurements of the moisture content, color pigments, and antioxidant compounds (total carotenoids, capsanthin, ascorbic acid, and total polyphenols) were completed during 120 days of storage at 4 and $30^{\circ}C$. We found that drying methods, storage temperatures, and packaging materials affected the American Spice Trade Association (ASTA) and Hunter color values, as well as the antioxidant content of paprika powder. There was a high correlation (r=0.87, p<0.01) between the ASTA color and the $a^*/b^*$ value. The loss of red color was closely related to the reduction of moisture content (r=0.81, p<0.01) during storage. Drying paprika with a low temperature in the absence of air resulted in better retention of the carotenoids and ascorbic acid. Also, as the retention of the carotenoids and ascorbic acid increased, the stability of the red pigment increased. Freeze-drying was found to be the most suitable drying method for the stability of the antioxidant compounds and red pigment.

• 한국축산식품학회지
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• 제21권3호
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• pp.208-214
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• 2001

This study was conducted to investigate the influence of dietary oriental medicine refuse(OMR) and mugwort powder on physico-chemical characteristics of Korean Native Pork(KNP). KNP were randomly assigned to one of the three dietary treatments : 1) control (commercial feed) 2) T1 (commercial fed supplemented with 10% OMR powder) 3) T2 (commercial feed with 10% mugwort powder). 15 heads(♂) were feed one of the experimental diets for 5 months and slaughtered. In the proximate composition, moisture content showed slightly high in the T1, however, fat content were tended to be high in the control. The heating loss, shear value, WHC (water holding capacity) were not significantly between control and the treatments group. The T1 showed the lowest pH among treatments (P<0.05). In sensory evaluation, juiciness and tenderness of T1 and T2 were higher compared with that of control. Hunter a* did not show any difference among the treatments group. But Hunter L*, b* in treatment group(T1, T2) were higher than that of the control. Oleic acid, linoleic acid and unsaturated fatty acid contents of T1 and T2 were higher than the control. The total amino acid of the control, T1 and T2 were 18.290, 18.177 and 18.942mg%, respectively.

• Journal of Magnetics
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• 제11권3호
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• pp.126-129
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• 2006

The phosphate coating on the $(Fe_{0.97}Cr_{0.03})_{76}(Si_{0.5}B_{0.5})_{22}C_2$ amorphous powders with an average size of 10 ${\mu}m$ in diameter has been carried out in aqueous 1.0-2.0 wt% $H_3PO_4$ solutions, and the consolidation behavior and magnetic properties of their compressed powder cores has been investigated. The phosphate coating could provide efficient electrical insulation between amorphous powders and improved consolidation ability at room temperature. Especially when the powders were treated in more concentrated phosphoric acid solution, enhanced phosphate covering and higher frequency/dc-bias stability were achieved. The powder cores phosphate-coated in 2.0 wt% $H_3PO_4$ solution exhibited constant permeability of 21 up to 10 MHz, 110 of the quality factor at 0.9 MHz, 610 mW/cm3 core loss at 100 kHz/0.1 T and 89 of percent permeability at 100 kHz.

• 한국식품영양학회지
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• 제34권4호
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• pp.321-330
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• 2021

The purpose of this study was to investigate the quality characteristics of bread made with 1%, 3%, 5%, and 7% of Bigeumdo Seomcho powder (Spinacia oleracea L.). The pH of dough and bread decreased as the amount of addition increased; 7% indicated the lowest. The moisture level correlated negatively with the powder addition, but the difference was not statistically meaningful (p<0.05). As the amount of addition was increased, the intensity of color increased but the volume decreased. The brightness and redness of the bread decreased as the amount of addition increased. The volume, specific volume, and baking loss rate correlated negatively with the powder addition. Regarding springiness, cohesiveness, and gumminess, the experiment group was higher than the control group and they lowered as the addition amount increased. The brittleness showed positive correlation with the addition amount. Out of the amino acids of bread, glutamic acid showed the highest value as the amount of addition was increased. Overall, it is possible to produce bakery bread using functional ingredients.

• 한국재료학회지
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• 제29권9호
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• pp.532-541
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• 2019

Information and communication technologies are developing rapidly as IC chip size becomes smaller and information processing becomes faster. With this development, digital circuit technology is being widely applied to mobile phones, wireless LANs, mobile terminals, and digital communications, in which high frequency range of GHz is used. In high-density electronic circuits, issues of noise and EMC(Electro-Magnetic Compatibility) arising from cross talk between interconnects or devices should be solved. In this study, sheet-type electromagnetic wave absorbers that cause electromagnetic wave attenuation are fabricated using composites based on soft magnetic metal powder and silicon rubber to solve the problem of electromagnetic waves generated in wireless communication products operating at the frequency range of 2.4 GHz. Sendust(Fe-Si-Al) and carbonyl iron(Fe-C) were used as soft magnetic metals, and their concentrations and sheet thicknesses were varied. Using soft magnetic metal powder, a sheet is fabricated to exhibit maximum electromagnetic attenuation in the target frequency band, and a value of 34.2dB(99.9 % absorption) is achieved at the target frequency.

• 한국식품영양과학회지
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• 제40권2호
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• pp.267-273
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• 2011

기능성 소재로서의 들깻잎 분말의 이용가능성을 알아보기 위해 들깻잎 분말 0, 5, 10 및 15% 첨가한 파운드케이크를 제조하여 품질 특성을 조사하였다. 반죽 및 파운드케이크의 pH는 들깻잎 분말 첨가에 의해 감소하였고, 굽기손실률은 첨가량에 따른 유의차가 나타나지 않았다. 높이는 들깻잎 분말의 첨가량이 증가할수록 감소하는 경향을 보였으며, 무게는 대조군의 값이 가장 높았지만 시료간의 유의차이는 나타나지 않았다. 파운드케이크의 색도 측정 결과는 L(lightness) 값과 b(yellowness)값에서 crust와 crumb 모두 들깻잎 분말 첨가량이 증가할수록 유의적으로 감소하였고, a(redness)값은 crust가 들깻잎 분말 첨가량이 증가할수록 유의적으로 감소하였지만, crumb은 대조군의 값이 가장 높았고 첨가군에서는 첨가량이 증가할수록 증가하는 것으로 나타났다. 파운드케이크의 관능검사 결과 들깻잎 분말 첨가는 색, 향미, 맛, 촉촉함, 전반적인 기호도를 향상시키는 긍정적인 영향을 미치나 10% 이상의 너무 많은 들깻잎 분말 첨가는 관능적인 기호도를 오히려 떨어뜨리는 것으로 나타났으며, 들깻잎 분말 5% 첨가군의 선호도가 가장 좋아 파운드케이크의 품질 및 관능적 특성을 고려한 들깻잎 분말 첨가량은 5% 첨가군이 최적 조건일 것으로 판단된다. 물성 측정 결과는 들깻잎 분말 첨가량이 증가함에 따라 경도는 증가한 반면, 탄력성, 응집성은 감소하였고, 검성과 씹힘성은 시료 간 유의적 차이를 보이지 않았으며, 저장 7일에는 들깻잎 분말 첨가에 따라 일정한 경향을 나타내지 않았다. 저장함에 따라 노화도는 증가하였는데, 들깻잎 분말 무첨가군의 노화도가 296.36%로 가장 낮았으며, 들깻잎 분말 첨가에 따라 5% 첨가군 306.44%, 10% 첨가군 334.47%로 증가하는 경향을 보이다가 15% 첨가군에서는 320.83%로 다소 감소하였다. 항산화 활성은 들깻잎 분말 첨가량이 증가할수록 유의적으로 증가하였으며, 저장에 따라 감소하는 경향을 보였다.

• 한국조리학회지
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• 제19권4호
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• pp.119-135
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• 2013

본 연구에서는 찰보리의 이화학적인 성분을 분석하고 찰보리 분말의 첨가량을 달리하여 식빵반죽과 식빵을 제조하여 물리적, 관능적 특성을 측정하였다. 일반 성분 분석 결과 찰보리 분말의 수분함량은 8.33%, 조단백은 10.47%, 조지방은 1.63%, 조회분은 2.97%로 나타났다. 찰보리 분말을 첨가한 식빵 반죽의 sedimentation value와 pelshenke value 측정 결과는 찰보리 분말 첨가량이 증가할수록 감소하였다. Water retention capacity와 alkaline water retention capacity 측정 결과는 찰보리 분말 첨가량이 증가할수록 증가하였다. 찰보리 분말을 첨가한 식빵 반죽의 farinograph 측정 결과 consistency, water absorption, development time, stability 및 time breakdown은 첨가량이 증가할수록 감소하였고, tolerance index는 증가하였다. 찰보리 분말을 첨가한 식빵 반죽의 amylograph 측정 결과 pasting temp T값은 첨가량이 증가할수록 증가하였고, peak viscosity P값, hot past viscosity H값 및 breakdown P-H 값은 감소하였고, final viscosity F값, setback F-H값은 유의적 차이 없었다. 찰보리 분말 첨가한 식빵의 굽기 손실률과 비용적은 첨가량이 증가할수록 감소하였다. 찰보리 분말을 첨가한 식빵의 색도 측정결과 L값, a값, b값은 첨가량이 증가할수록 유의적 차이가 없었다. 찰보리 분말을 첨가한 식빵의 texture 측정 결과 경도와 점착성은 첨가량이 증가할수록 증가하였고, 응집성, 탄력성 및 씹힘성은 감소하였다. 기호도 검사 결과는 맛, 촉촉함, 부드러움, 씹힘성과 전반적인 기호도는 10% 첨가군이 가장 높게 나타났다.