• 한국결정성장학회:학술대회논문집
• /
• 한국결정성장학회 1996년도 제11차 KACG 학술발표회 Crystalline Particle Symposium (CPS)
• /
• pp.129-153
• /
• 1996

In aqueous slurry processing of silicon nitride, the interaction of dispersant and binder on the surface of particles was studied to identify the effect of these additives on ceramic powder processing. Polymethacrylic acid (PMAA) and polyvinyl alcohol (PVA) were used as dispersant and binder, respectively. the adsorption isotherms of PMAA and PVA for the silicon nitride suspension were determined, while the adsorption of PMAA was differentiated in the mixed additive system by ultraviolet spectroscopy. These experiments were done in order to investigate the effect of these organic additives on the physicochemical properties of silicon nitride suspensions. The electrokinetic behavior of silicon nitride was subsequently measured by electrokinetic sonic amplitude (ESA). As PMAA adsorbed onto silicon nitride, the isoelectric point (pHicp) shifted from pH=6.7 to acidic pH, depending on the surface coverage of PMAA. However, adsorption of PVA did not change the pHicp of suspensions, but did decrease the surface potential of silicon nitride moderately. The rheological behavior of silicon nitride suspensions was measured to assess the stability of particles in aqueous media, and was correlated with the electrokinetic behavior and adsorption isotherm data for silicon nitride.

• 한국세라믹학회지
• /
• 제44권1호
• /
• pp.6-11
• /
• 2007

The rheological properties of slag cement pastes by effect of particle size distribution of binder were investigated using a Rheostress 1 rheometer (Haake) with a cylindrical spindle and the relationship between fluidity particle size distribution using the Rosin-Rammler equation. Samples are combined the two types of slag powder and OPC, fine slag particles sized Elaine specific surface area $8,000cm^2/g$, coarse slag particles sized Elaine specific surface area $2,000cm^2/g$, intermediate OPC particles $3,450cm^2/g$, used to search for the combination that would yield the best quality product. The all flow curves which were measured by rheometer showed hysterisis and could be classified into 4 types. When the combination was based on a ratio of 15-20 vol% fine particles, 40-50 vol% intermediate particles, 30-40 vol% coarse particles of the total volume, a high fluidity and low yield-strength was achieved. The Rosin-Rammler function can explain aboved correlation flow curve types. On type 1, the n-value had a correlation with plastic viscosity however the blend of type 2 and 3 showed consistent n-value regardless of plastic viscosity. In addition, the blend in type 4 tended to a rise in fluidity according to the increase of the n-value.

• 한국축산식품학회지
• /
• 제38권3호
• /
• pp.476-486
• /
• 2018

In this study, the droplet size distribution, rheological properties, and stability of dairy cream-based emulsions homogenized with different sucrose fatty acid ester (SFAE, a non-ionic small-molecule emulsifier) concentrations (0.08%, 0.16%, and 0.24% w/w) at different homogenization pressures (10 MPa and 20 MPa) were examined. Homogenization at a high pressure resulted in a smaller droplet size and narrower droplet size distribution. The D[4,3] (volume-weighted mean) and D[3,2] (surface-weighted mean) values of the emulsions decreased with an increase in the SFAE concentration. The flow properties of the emulsions homogenized with SFAE showed shear-thinning (n=0.21-0.46) behavior. The apparent viscosity (${\eta}_{a,10}$) and consistency index (K) of the homogenized emulsions were lower than those of the control sample that is non-homogenized and without SFAE, and decreased with an increase in SFAE concentration. The storage modulus (G') and loss modulus (G") of all emulsions homogenized with SFAE were also lower than those of the control sample. The stability of all emulsions with SFAE did not show any significant change for 30 d at $5^{\circ}C$. However, the emulsions stored at $40^{\circ}C$ were unstable over the storage period. Therefore, the addition of SFAE enhanced the stability of dairy cream emulsions during storage at refrigeration temperature ($5^{\circ}C$).

• 한국식품조리과학회지
• /
• 제23권4호통권100호
• /
• pp.481-491
• /
• 2007

This study was conducted to develop pizza crust with additions of Chungkukjang and onion. The stickiness of the pizza dough containing fresh Chungkukjang (C), heated Chungkukjang (HC), and fresh Chungkukjang with added dough-improver (CI), was measured to evaluate the dough properties. The optimum conditions for pizza crust preparation relating to the processing suitability and sensory quality were established using response surface methodology (RSM). When HC and CI were used in dough making, dough stickiness was reduced to 37% and 51%, respectively. Therefore, the dough-improver(2%) offered the pizza dough better rheological properties when C was used without heat treatment. On the other hand, processing suitability such as the spreadability and overall acceptability, which included the smell and taste of the pizza, were impaired as the amount of CI increased. However, the use of fresh ground onion in the pizza dough compensated for these impairments. The optimum conditions for pizza crust making as determined by RSM were 25.1% onion, 7.1% Chungkukjang, and 52.3 min of fermentation time.

• 한국식품조리과학회지
• /
• 제19권4호
• /
• pp.429-438
• /
• 2003

The optimization of Omija-pyun as a traditional dessert, with the most European taste and year round availability, was studied with regard to its texture. The response surface methodology was used to determine the optimal composition of Omija-pyun as a European style dessert. The texture, including the springiness, gumminess, cohesiveness, adhesiveness, hardness and chewiness, was measured using TPA parameters (TA-HD Texture Analyser, stable micro system, UK). The texture of Omija-pyun was influenced by pectin and sucrose to the first linear order. The properties of springiness and adhesiveness were influenced by pectin x pectin to the second quadratic order. No cross product effects between ingredients were found from the analysis. The maximum springiness was obtained with 42g of pectin, 450g of sucrose, 110g of glucose syrup and 4.8g of tartaric acid. The maximum chewiness was with 55g of pectin, 330g of sucrose, 140g of glucose syrup and 5.7g of tartaric acid. The maximum adhesiveness was achieved using 17g of pectin and 400g of sucrose. The gumminess and hardness increased with increasing pectin content, and a cross product effect was observed(Eds note: you said earlier that no cross product effects between the ingredients was found\ulcorner) between sucrose and glucose syrup.

• Elastomers and Composites
• /
• 제34권5호
• /
• pp.407-413
• /
• 1999

비세라믹 복합절연소재는 기계적 물성, 환경문제, 대량생산과 용이한 설계등의 우수한 특성으로 인해 전력산업분야에서 관심의 대상이 되어왔다. 또한 세라믹 절연체에 비하여 가볍고, 더욱 강인한 물성을 가진다는 장점이 있다. 본 연구에서는 뛰어난 전기 절연 특성과 우수한 내열, 내산화, 내오존성과 내후성을 가진 ethylene propylene diene monomer(EPDM)를 절연소재로 사용하였다. 특히, EPDM은 다른 고무 복합체에 비해 우수한 소수성을 가지기 때문에 장기간 사용이 가능하다는 점에서 본 연구에서는 EPDM 복합체의 유변학적 물성, 전기적물성, 그리고 접촉각의 측정을 통한 소수성 및 회복력에 관한 연구를 하였다. 또한 SEM을 사용하여 표면 형태학적 연구를 수행하였다.

• Elastomers and Composites
• /
• 제41권2호
• /
• pp.97-107
• /
• 2006

폐타이어와 폐수지 처리 문제를 해결하기 위한 방법으로 재생 폴리에틸렌 수지와 신재HDPE를 폐타이어 분말(GWTP)과 치합형 동방향 회전 이축 압출기(Fuly Intermeshing Co-rotating Twin Screw Extruder)를 이용하여 각 조성별로 용융 훈련하여 재생 PE/폐타이어 복합체를 제조하였다. 본 연구에서는 플라스틱 수지 (재생 PE, HDPE)와 폐타이어 분말의 혼합비를 $0\sim50$wt.%로 하였으며, ASTM에 의거하여 인장강도, 파단신율, 충격강도 등의 물성 변화를 확인하였다. 폐타이어 분말 함량이 증가할수록 인장강도가 감소하고 파단신율이 증가하였다. 한편 충격강도는 폐타이어 분말 함량이 30 wt.%일 때 최대이고, 함량이 증가할수록 충격 강도가 감소하는 경향을 나타내었다. 형태학적 고찰에서는 폐타이어 분말의 함량의 증가함에 따라 파단면이 거칠어지는 형상을 관찰하였다. 모세관점도계(Capillary Rheometer)를 이용하여 재생 PE/폐타이어 분말 복합체의 전단속도의 변화에 따른 용융전단점도의 변화와 연화점 (Ts) 등의 유변학적 성질을 분석한 결과, 폐타이어 분말 함량 증가에 따라 외부 응력에 대한 흐름 저항성을 증가시켜 용융점도가 상승하는 결과를 보였으며 측정된 전단율에서 전단 점도는 Power-law 거동을 보였다.

• 한국식품저장유통학회지
• /
• 제19권6호
• /
• pp.841-848
• /
• 2012

모시죽의 가용성 고형물 함량은 7.40-11.60 brix, pH는 6.0-6.6 사이에서 변화하는 것을 알 수 있었다. 모시죽의 amylose함량은 가수량에 의해 유의적인 영향을 받았으며 가수량이 증가할수록 현저하게 감소하는 것으로 나타났다. 점성은 가수량이 증가할수록 급격하게 떨어지는 것을 보여 주었으나, 모시분말은 죽의 점성 특성에 영향을 미치지 못하였다. 퍼짐성은 가수량이 증가할수록 현저하게 증가하는 경향을 보여주었으며, 이는 점성이 증가할수록 퍼짐성은 떨어진다는 사실과 일치된 결과를 보여주었다. 모시 첨가량이 증가할수록 밝기는 현격히 감소하는 것으로 조사되었으며 가수량의 변화는 밝기에 거의 영향이 없는 것으로 나타났다. 모시분말 첨가량은 적색도를 감소시키는 것으로 조사되었으나 황색도는 모시분말 첨가비를 증가시킬수록 크게 증가하는 것으로 나타났다. 모시죽의 제조조건에서 가수량은 물성특성에 모두 유의적으로 영향을 미치는 것으로 분석되었으나 모시분말 첨가비율은 유의성이 인정되지 않아 설정된 범위 내에서는 물성에 대한 영향이 크지 않는 것으로 평가되었다.

• 한국인쇄학회지
• /
• 제23권2호
• /
• pp.1-14
• /
• 2005

Generally, printing inks are composed of pigment, vehicle and additive. Among others, the vehicle transfers the pigment to substrate and then binds it on the surface. So, rheological properties of the vehicle are an important factor which has influence on printability. Thus, in this study, rheology of the vehicle was investigated by using rotational rheometer according to molecular weight of resin. Also, emlusion rheology of water in oil type and its microstructure were examined with increasing the shear rate. Consequently, the following results were obtained: (1) By viscometric flow test, zero shear viscosity and shear thinning index of vehicle increased with increasing the molecular weight of resin. (2) By relaxation and creep test, relaxation time and retardation time of vehicle increased with increasing the molecular weight of resin. (3) By frequency sweep test, crossover point of vehicle increased with increasing the molecular weight of resin. (4) G' and G" of emlusions increased with increasing the molecular weight by amplitude sweep test. (5) The shape of water drop in emlusions was changed to the capillary tube.

• 한국인쇄학회지
• /
• 제19권1호
• /
• pp.28-41
• /
• 2001

Rheological properties of ink and Ink-Water balance are the important factors in lithographic printing. Laboratory test method which determines the emulsification rate of dampening solution and ink has been described. The emulsification theory and laboratory test method deduced from Surland and it has become a useful tool for the industry. The effects of pH value and surface tension of dampening solution on the emulsification rate has been tested by many researcher. In this paper we focused on the factors which influence in the emulsification such as pH and surface tension of dampening solution and emulsifying temperature. To study on the factors determining the emulsion velocity, we have measured water pickup and calculated emulsion velocity constant 'k' and activation energy.