• KCI Concrete Journal
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• 제13권1호
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• pp.35-41
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• 2001

This paper investigated rheological properties of binder pastes for self-compacting high performance concrete. Six mixtures of self-compacting concrete were initially prepared and tested to estimate self-compacting property. Then, the binder pastes used in self-compacting concrete were tested for rheological properties using a rotary type rheometer. Binder pastes with different water-binder ratios arid flow values were also examined to evaluate their rheological characteristics. The binders were composed of ordinary Portland cement, fly ash, two types of pulverized blast-furnace slag, and limestone powder. The flow curves of binder pastes were obtained by a rotary type rheometer with shear rate control. Slump flow, O-funnel time, box, and L-flow teats were carried out to estimate self-compacting property of concrete. The flow curves of binder pastes for self-compacting concrete had negligible yield stresses and showed an approximately linear behavior at higher shear rates beyond a certain limit. Test results also indicated that the binders incorporating fly ash are more appropriate than the other types of binders in quality control of self-compacting concrete.

• 한국안전학회지
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• 제32권5호
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• pp.54-61
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• 2017

The purpose of this study is to develop standard reference materials for safety control of construction materials considering the required performance of standard materials including flow performance incorporating particles. The flow characteristics of concrete are very complicated depending on mixing proportions of constituent materials, admixtures, amount of mixing, type of mixer, time of mixing, temperature and so forth. Uncertainties and multidimensional properties of concrete have been evaluated through various studies but there are few researches for the development of standard reference material. In this study, based on the rheological concept, the flow performance of construction materials was evaluated to understand the properties of standard reference materials and was finally obtained representing materials which simulate the standard reference materials.

• Preventive Nutrition and Food Science
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• 제10권3호
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• pp.224-230
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• 2005

The effects of low viscosity chitosan on the rheological properties of soymilk using a model system and on tofu qualities were examined. The flow behavior of soy milk with chitosan closed the Newtonian flow and stabilized according to increasing chitosan concentration. The soymilk containing $glucono-\delta-lactone$ exhibited a more pseudoplastic flow behavior compared with that of the control soymilk. The addition of low viscosity chitosan to the tofu preparation did not significantly affect its physicochemical properties. However, the results of the TEM image and instrumental textural properties showed that low viscosity chitosan affected the construction of the tofu structure. Chitosan tofu had low scores across the whole field of appearance in the sensory evaluation, and its overall eating quality was scored significantly lower. These results suggest that the addition of low viscosity chit os an affects the quality of tofu, which changes according to the degree of polymerization and concentration of chitosan.

• Food Science and Biotechnology
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• 제14권6호
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• pp.871-874
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• 2005

The effect of rice starch at different concentrations (0, 4, 6, and 8%) on dynamic rheological properties of surimi sols was investigated by small-deformation oscillatory measurements at $10^{\circ}C$ and during heating from 10 to $95^{\circ}C$. Dynamic frequency sweeps at $10^{\circ}C$ showed that the magnitudes of storage modulus (G') decreased with increasing starch concentration while those of tan $\delta$ increased. G' values of surimi-rice starch sols during heating decreased with increasing starch concentration, indicating that the pattern of G' changes during heating was influenced by the concentration of the added rice starch. In general, the characteristic G' thermograms of all samples showed a similar sol-gel transition pattern.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.227-233
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• 2005

Fungal strain CGF was isolated from the soil of ChungNam Province, South Korea. Based on the 28S rDNA sequence analysis and the sequence of the internal transcribed spacer (ITS) region of ribosomal DNA, together with morphological and cultural characteristics, this strain was identified as Aspergillus sclerotiorum and renamed Aspergillus sclerotiorum CGF. This is the first strain of Aspergillus sclerotiorum identified in Korea. When the antifungal activity of A. sclerotiorum CGF was evaluated, among the phytopathogenic fungi, mycelial growth of only Phytophthora species was inhibited. Oermination of P. capsid zoospore was also inhibited. The bioactive compound of A. sclerotiorum CGF was highly thermo- and pH-stable.

• 한국분말재료학회지
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• 제9권4호
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• pp.251-260
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• 2002

In the viscosity measurement of PIM feedstock, slip correction methods require a number of experiments and produce a high level of error. In this study, a rotational rheometer with a parallel-discs configuration having different surface roughness was tried to minimize the effect of the slip phenomenon. Disc surface was prepared in 3 different roughness conditions - a smooth and 2 roughened surfaces. Results with the roughened surfaces were compared with the results obtained with a slip correction method. Relationship between powder characteristics such as size and shape and a surface roughness of the disc was examined for feedstock of 4 different powders with a same binder. As results, the effect of the slip phenomenon could be sufficiently minimized on the roughened surface in most cases. However, the effect of the slip phenomenon could not be sufficiently minimized for feedstock of a round-particular-shape powder and in the case of very narrow gap size.

• Preventive Nutrition and Food Science
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• 제12권4호
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• pp.229-233
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• 2007

This study was conducted to investigate the quality characteristics of cookies added with different levels of tomato powder. Cookies were prepared with five different levels of tomato powder (0, 2.5, 5.0, 7.5, and 10.0%) and the physicochemical properties were examined. The pH of cookie dough decreased significantly by the addition of tomato powder (p<0.05). Crude protein and ash content of the cookies containing 5.0, 7.5 and 10.0% tomato powder were significantly higher than those of control and those with 2.5% (p<0.05). The spread factor of control cookie was lower than that of cookies containing 5.0, 7.5, and 10.0% tomato powder. The incorporation of tomato powder in cookies lowered the lightness values but increased redness and yellowness values. Rheology testing showed that cookies with 5.0, 7.5, and 10.0% tomato powder had significantly lower hardness value than control. Sensory evaluation revealed that overall desirability scores were not significantly different between control and tomato powder added groups. Therefore, cookies with up to 10.0% added tomato powder would be as acceptable as control cookies without depressing cookie quality.

• Preventive Nutrition and Food Science
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• 제14권2호
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• pp.148-155
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• 2009

The purpose of this study was to find new applications for Rubus coreanus and to produce new products. Jelly prepared with Rubus coreanus was studied and analyzed with regard to its composition, rheology and sensory evaluation. The technique of response surface methodology was used to analyze the results, which showed 16 experimental points including 2 replicates for Rubus coreanus juice, gelatin and sucrose. Rheological characteristics such as lightness, redness, yellowness and hardness, springness, chewiness and gumminess were shown to be significant, and these were mostly influenced by the content of Rubus coreanus juice. Significant sensory characteristics such as color, flavor, transparency, taste and the overall quality were also found to be greatly influenced by Rubus coreanus juice and gelatin in general. Based on the overlapping categories of factors that satisfied all sensory categories, the maximally optimized point was taken as the middle point. This value was determined to be 43.28 g of Rubus coreanus juice and 9.19 g of gelatin for every 140.00 g of sucrose.

• 한국식품영양학회지
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• 제30권6호
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• pp.1310-1318
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• 2017

This study was conducted to evaluate characteristics of bread and rheology of flour dough containing fructooligosaccharide. In the farinogram test, addition of fructooligosaccharide changed stability and development time. Stability and development time increased as the amount of fructooligosaccharide increased. In the extensograph test, the degree of extension decreased with increasing of fructooligosaccharide content, whereas degree of resistance increased. The volume of the loaf bread containing 10% fructooligosaccharide was the largest, and the bread containing 15% fructooligosaccharide revealed the best taste, flavor, and texture scores. After fermentation treatment, the volume of the dough with 20% of sucrose were less than that of 20% of fructooligosaccharide. Dough with 20% of sucrose revealed lowest dough raising power compared to other doughs. Overall, preference scores by sensory evaluation of bread containing fructooligosaccharide were higher than that of bread with sucrose. Therefore, excellent quality of bread may be achieved by adding fructooligosaccharide instead of sucrose to the process.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.209-216
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• 2002

Bacillus sp. A56 was studied, because of its high flocculating activity. The flocculating substance produced by this strain was purified by ethanol precipitation, cetylpyridinium chloride (CPC) precipitation, and gel permeation chromatography (GPC). The FT-IR spectrum of the purified bioflocculant, designated as BF-56, showed typical characteristics of polysaccharides. The non-sugar substituents, and sugar components of BF-56 containing glucose, fucose, glucuronic acid, and galactose in an approximate molar ratio of 2.76:1.10:1:0.12, suggested that it was a novel bioflocculant with an estimated molecular mass of over $7{\times}10^3$ kDa. Rheological analysis of BF-56 revealed that it was a pseudoplastic that had higher apparent viscosity rate at dilute concentrations than those of zooglan. The solution of bioflocculant BF-56 exhibited non-Newtonian characteristics and it was compatible to high concentrations of salts such as KCl, NaCl, $CaCl_2,\;or\;FeCl_3.$ The present results suggested strong possibility of bioflocculant BF-56 to be fully applicable to industries such as wastewater treatment.