• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.181-184
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• 2009

로켓시스템의 에너지원으로 적용할 수 있는 기체발생기용 복합 고체추진제의 개발과정을 기술한다. 80%의 고체입자 부하율과 양호한 유동성, 그리고 $-50^{\circ}C{\sim}70^{\circ}C$에서 경화에 적절한 추진제 물성을 갖는 HTPB를 바인더로 하여, 낮은 화염온도, 적은 고체입자 잔사, 무독성 생성물의 추진제 제조가 가능한 AN을 제1종 산화제로, 탄도특성 제어에 필요한 AP를 제2종 산화제로 추진제 주요 조성이 구성된다. 기본조성을 근거로 하여 일련의 물성개선 시험이 수행되었으며 최대응력 8 bar 및 최대응력점 변형율 30%, 그리고 탄성계수 1000 psi 수준의 물성을 갖는 추진제 조성을 얻을 수 있었다.

• 동아시아식생활학회지
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• 제20권2호
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• pp.307-312
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• 2010

Sugar snap cookies were prepared with the addition of carrot powder (2~12%) as a source of dietary fiber. Analyses of physiochemical properties, rheology and sensory evaluation of the cookies were conducted. Increasing carrot powder content weakened the flour, as evidenced by decreased diameter and increased thickness, which resulted in decreased spread factor. The water content of the carrot powder-amended cookies and unamended flour was not significantly different. The pH and L values progressively decreased and a and b values progressively increased with increasing addition of carrot powder. Textural analysis revealed no significant differences in brittleness with carrot powder addition, even though brittleness did decrease with the addition of more carrot powder. Sensory evaluation revealed a preference for cookies prepared with 2~4% carrot powder, with decreased preference at powder concentrations exceeding 6%. Addition of a dried vegetable with high fiber content caused the dietary fiber to absorb much water content, resulting in decreased diameter, increased thickness and decreased spread factor. Therefore, it is deemed desirable to increase the spread factor by controlling the water content and adding emulsifiers so as to enhance the functionality and maintain the quality of cookies.

• 대한영양사협회학술지
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• 제26권1호
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• pp.1-13
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• 2020

This study was undertaken to optimize preparation of sweet rice muffins using lotus (Nelumbo nucifera Gaertn) seed powder. The experimental conditions used in the preparation included lotus seed powder (X₁) and soybean oil (X₂). The muffin formulation was optimized using rheology. Lightness (P<0.01) displayed a quadratic model pattern, whereas yellowness (P<0.01) and redness (P<0.05) was presented a linear model. Texture properties significantly differed in cohesiveness (P<0.05). Evaluating the sensory characteristics of muffins, except for flavor and texture, the remaining properties of color (P<0.01), taste, overall quality, and appearance (P<0.05) were found to be significantly different. The overall quality was also affected by the proportion of lotus seed powder, rather than the amount of soybean oil. The optimal ratio for palatability of muffins was determined to be 47.80 g lotus seed powder and 95.28 g soybean oil. Taken together, our results indicate that sweet rice muffins prepared using lotus seed powder are sufficiently competitive in terms of function and quality.

• 한국인쇄학회지
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• 제23권2호
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• pp.117-128
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• 2005

Printing inks are basically dispersions of solid pigment particles in a vehicle. Pigment flocculation and/or colloidal aggregates created by thixotrope additives form a three- dimensional network in the inks. This structure complicates the flow behaviour of inks. However, if the internal structure is formed under control, the printing process will benefit from it because the ink must satify rheological requirements over a very wide range of shear conditions. The presence of internal structure results in the following prominent non-Newtonian rheological properties: viscoelasticity, yield stress, shear thinning and thixotropy. If the components of printing inks were changed, the rheological characteristics such as viscosity, yield stress, viscoelasticity and tack value were considerably varied. Thus, in this paper, the effects of changing the content of rosin modified phenolic resin on rheological properties of the vehicle will be studied. For that, the rheological properties were found by flow, yield stress, creep and oscillation measurements using Bohlin C-VOR Rotational Rheometer. And Emulsion rheology and its microstructure will be investigated.

• 한국식품영양학회지
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• 제33권6호
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• pp.681-691
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• 2020

This study was conducted to evaluate the characteristics of bread and the rheology of flour dough containing chlorella powder(0%, 0.5%, 1.0%, 1.5%, 2.0% and 2.5%). In the farinograph test, the addition of chlorella powder changed water absorption, development time and mixing tolerance index for making bread. As the amount of chlorella powder increased, the water absorption increased, mixing tolerance index and the development time decreased. In the extensograph test, the degree of extension and resistance was decreased with increasing of chlorella powder content. In the amylograph test, the maximum viscosity was slightly decreased with increasing of chlorella powder contents. The colors of L value in bread crumb was significantly decreased as the chlorella powder addition. After fermentation treatment, The dough with 2.5% chlorella powder showed the lowest dough raising power compared to the other doughs. The addition of the chlorella powder had significant effect on bread texture. The bread consisting of 0.5% chlorella powder showed the highest volume of loaf and specific volume. Therefore, high quality of bread can be achieved by adding chlorella powder.

• Advances in concrete construction
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• 제10권5호
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• pp.381-391
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• 2020

This study aimed to develop reference materials (RMs) for mortar that can simulate the initial flow characteristics with constant quality over a long period. Through the previous research on the development of RMs for cement paste, the combination of limestone, glycerol, and water was used as the basic matrix for developing RMs for mortar in this study. In addition, glass beads of three particle sizes (0.5, 1.0, and 2.0 mm) and ISO standard sand were selected as tentative candidates to derive fine aggregate substitutes. The mixture of glass beads could simulate the initial flow characteristics of mortar, but under the same mixing ratio, replicates showed an unstable tendency to indicate inconsistent values due to the generation of electrostatic properties between materials and equipment. On the other hand, the mixture using ISO standard Sand not only simulates the constant flow characteristics for a long period of time, but also shows stable results with little error in replicates. Therefore, limestone, glycerol, ISO standard sand, and water were finally determined as components that met the required properties of RMs for mortar. The effect of each component on the flow characteristics of RMs was analyzed. It was found that glycerol increased the cohesion between the particles of standard sand, resulting in a constant increase both in the plastic viscosity and yield stress. Both limestone and standard sand had a dominant effect on the yield stress. The relationships between various mortar mixing ratios and the corresponding mixing ratios of RMs were established. In addition, the results of the verification experiment showed that the rheological properties of the RMs obtained through the relationships correlated with various water/cement ratios and the fine aggregate volume fractions of mortar obtained with same manner. In other words, the RMs for mortar developed in this study can be used as standard samples because they can simulate the initial flow characteristics of mortar of various mixing ratios for a long period without any chemical changes.

• 유변학
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• 제11권1호
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• pp.34-43
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• 1999

수지 이동 성형공정에서 섬유직조가 수지에 의해 함침될 때 발생하는 기공 또는 나쁜 젖음성은 최종 성형품의 물성 저하에 심각한 영향을 미치게 된다. 본 연구에서는 수지이동 성형공정에서의 이러한 문제점을 극복하기 위한 기초 데이터를 제공하기 위하여, 실란 커플링제를 사용한 섬유의 표면 개질이 수지의 유동특성과 수지와 섬유 사이의 젖음성 및 기공함량에 미치는 영향을 조사하였다. 빔 형태의 금형을 대상으로 에폭시 수지와 평직형태의 유리섬유를 사용하여 미시적인 유동가시화 실험 및 경화실험을 수행하였다. 섬유의 표면을 개질함으로써 수지와 섬유 사이의 동적 접촉각이 감소하고 위킹속도는 증가한 것으로 나타났으며, 이러한 결과로부터 본 연구에서 사용한 화학적 표면개질이 섬유직조의 젖음성 및 미시적 흐름 거동을 향상시킬 수 있는 중요한 요인임을 확인할 수 있었다. 또한 수지의 높은 온도와 낮은 침투 속도는 동적 접촉각을 감소시키기 위한 중요한 가공 변수임을 알 수 있었다. 그러나 섬유직조의 투과성은 표면을 개질하였을 경우 오히려 감소하였는데, 이는 젖음성의 향상으로 인하여 수지와 섬유 사이의 접촉시간의 증가에 기인하는 것으로 생각된다. 마지막으로 경화공정을 통해 제조된 시편의 기공 함량을 측정 비교한 결과, 표면개질은 수지이동 성형공정에서의 기공형성에도 중요한 변수로 작용하여, 수지와 섬유 사이의 젖음성을 향상시키고, 최종 성형품의 기공함량을 감소시킴을 확인할 수 있었다.

• 한국식품영양과학회지
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• 제33권9호
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• pp.1566-1572
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• 2004

냉동 반죽 제조시 azodicarbonamide(ADA) 첨가량을 달리하여 만든 냉동 반죽의 물성에 미치는 영향인 farinogram, amylogram, extensogram을 비교 조사하였고, 냉동 반죽의 품질을 결정하는 2차 발효 시간, 빵 제품의 pH, 수분 함량, 비용적 및 경도에 미치는 영향을 -20$^{\circ}C$ 냉동고에서 제조 직후부터 12주까지 저장하면서 비교 조사하였다. ADA 첨가량이 증가할수록 farinogram에서 반죽의 흡수율, 안정도와 강력도는 증가하고, 흡수 시간과 약화도는 감소하였으며, amylogram에서 호화 개시 온도와 최고 점도는 증가하고, 최고 점도시 온도는 감소하였다. 또한 extensogram에서는 발효시간 45분에서 면적, 신장도와 저항비는 증가하고, 저항도는 감소되었다. 냉동 반죽 제빵법으로 만든 냉동 반죽은 같은 냉동 저장 기간에서 ADA 첨가량이 증가할수록 2차 발효시간, 수분 함량 및 경도 값은 감소하였으며, pH, 비용적은 증가하였다.

• 한국축산식품학회지
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• 제38권5호
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• pp.866-877
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• 2018

Cheese emulsion is an intermediate product for the production of cheese powder and needs to be stable, homogeneous and pumpable characteristics to convey to the spray drier. This study was conducted to evaluate the effects of fat reduction and emulsifying salt (ES) amount in cheese emulsion systems on the physicochemical characteristics. Reduced-fat (RF) and full-fat (FF) white-brined cheese emulsions were produced with different dry matters (DM; 15%-25% excluding ES) and ES concentrations (0%-3% based on cheese weight). Stable cheese emulsion was obtained at lower DM in RF cheese emulsion than that of FF cheese emulsion. Reduction in the amount of ES resulted in instability of both emulsions. Apparent viscosity with pseudoplastic flow behavior significantly increased with the decrease of fat content in stable cheese emulsions. Microstructure of emulsions appeared to be related to the fat content, stability and degree of emulsification. Reduction of fat content caused to get less lightness and more greenness in color, whereas yellowness was significantly decreased by increase in the amount of ES. In conclusion, fat reduction resulted in higher viscosities of cheese emulsion due to inducing the increment of protein, and the addition amount of ES considered as very important factor to produce stable cheese emulsion without protein precipitation or cream separation. Therefore, for preparation of RF cheese emulsion using a variety of white-brined cheese, lower amounts of DM would be suggested in this study to obtain homogenous droplets in the atomizing process of spray drying.

• 한국축산식품학회지
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• 제34권4호
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• pp.552-557
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• 2014

This study investigated the effects of ${\gamma}$-aminobutylic acid (GABA) on the quality and sensorial properties of both the GABA/NaCl complex and model meat products. GABA/NaCl complex was prepared by spray-drying, and the surface dimensions, morphology, rheology, and saltiness were characterized. For model meat products, pork patties were prepared by replacing NaCl with GABA. For characteristics of the complex, increasing GABA concentration increased the surface dimensions of the complex. However, GABA did not affect the rheological properties of solutions containing the complex. The addition of 2% GABA exhibited significantly higher saltiness than the control (no GABA treatment). In the case of pork patties, sensory testing indicated that the addition of GABA decreased the saltiness intensity. Both the intensity of juiciness and tenderness of patties containing GABA also scored lower than the control, based on the NaCl reduction. These results were consistent with the quality characteristics (cooking loss and texture profile analysis). Nevertheless, overall acceptability of the pork patties showed that up to 1.5%, patties containing GABA did not significantly differ from the control. Consequently, the results indicated that GABA has a potential application in meat products, but also manifested a deterioration of quality by the NaCl reduction, which warrants further exploration.