• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.9-16
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• 2018

Recently, the demand for eco-friendly parts has increased to reduce materials and parts that use fossil fuels. This has exacerbated the increase of energy prices and the enforcement of regulations by environmental agencies. Currently, polylactic acid (PLA) is a solution, as a common and eco-friendly material. PLA is a biodegradable material that can replace traditional petrochemical polymers. PLA has great advantages since it is resistant to cracking and shrinkage. When it is manufactured, there are few harmful byproducts. Improvement in the brittleness characteristics is another important task to be monitored throughout the production of industrial parts. Improvement in the brittleness property of products lowers the tensile strength and tensile elasticity modulus of the parts. This study focused on the mechanical properties of 3D-printed PLA parts. Tensile tests are performed while varying the infill print parameters to evaluate the applicability of PLA in several industrial areas.

• Culinary science and hospitality research
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• v.10 no.4
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• pp.165-177
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• 2004

This study was accomplished to examine possibilities to apply Korean medicine to breamaking. Extracts of Chungpesagan-tang prepared by the prescription of Korean medicine were used for baking, instead of water among ingredients of baking. Effects of addition of extracts of Chungpesagan-tang on various baking properties were analyzed during the process of baking. Changes in pH values and volumes of doughs during fermentation and pH values of bread showed no differences among samples. Loaf volumes and specific loaf volumes were increased somewhat on addition. The values of cohesiveness, springness, gumminess and brittleness of breads, which were measured by rheometer, were increased on addition while those of hardness were decreased a little. Lightness values of sections of loaves were decreased on addition, but their color differences were increased largely on color difference meter. There were nearly little differences among samples in all the values of parameters of external and internal characteristics and eating qualities of breads by sensory evaluation. Re-purchasing attitude of pullman bread added with Chungpesagan-tang had a high in the gender and age.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.3
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• pp.210-217
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• 2002

This study was carried out to investigate the possibility of improving the texture and the flavor of Dasik made of the Omija extract, various sugars and rice powder. Sensory quality and mechanical characteristics of Dasik were compared. The moisture content of the Croup of tile Dasik added with Omija extract was higher than that with non-Omija extract The Omija Dasik containing molasses showed the highest value (23.5%) in moisture content. In sensory quality, Omija Dasik containing honey and symp showed the highest score in overall acceptability (6.2 and 6.0, respectively). The Rice Dasik containing syrup showed the highest values in lightness (L) and yellowness (b) in color. The Omija Dasik containing syrup showed the highest values in redness (a) in color. The Dasik added with honey and syrup were lower in hardness, but higher in cohesiveness, springiness, gumminess and brittleness of textural characteristics. When sensory quality and mechanical characteristics of the Dasik were compared with, the gumminess and brittleness in mechanical characteristics were positively correlated with the appearance and the taste acceptability in sensory quality (p<.01, p<.05). The springiness was negatively correlated with the tooth packing in sensory quality (p<.001). The Omija Dasik was more desirable in flavor, taste and overall acceptability, especially those added with honey and syrup. From the above results, the honey might be replaced by the less expensive syrup, when making the Omija Dasik.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.326-331
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• 2001

In this study. CT specimens were prepared from ASME SA5l6 which was used for pressure vessel plates for room and low temperature service. And we got the following characteristics from fatigue crack growth test carried out in the environment of room and low temperature at $25^{\circ}C$, -3$0^{\circ}C$, -6$0^{\circ}C$, -8$0^{\circ}C$, -10$0^{\circ}C$ and -12$0^{\circ}C$ in the range of stress ratio of 0.1 by means of opening mode displacement. At the constant stress ratio, the threshold stress intensity factor range ΔKsub/th/ in the early stage of fatigue crack growth ( Region I) and stress intensity factor range ΔK in the stable of fatigue crack growth ( Region II) was increased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region. The straight line slope relation of logarithm da.dN -ΔK in RegionII, that is, the fatigue crack growth exponent m increased with descending temperature at the constant stress ratio. It assumed that the fatigue crack growth rate da/dN is rapid in proportion to descend temperature in Region II and the cryogenic-brittleness greatly affect a material with decreasing temperature.

• Korean journal of food and cookery science
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• v.2 no.2
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• pp.68-75
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• 1986

The changes of dietary fiber and texture of radish Kimchi fermented at $17{\sim}20^{\circ}C$ were investigated. During the fermentation period, hardness and brittleness of radish Kimchi were decreased. The changes were more marked in the brittleness. But the contents of cellulose and hemicellulose were not changed considerably. The contents of AIS was decreased with fermentation. During the fermentation, hot soluble pectin was increased and protopection was decreased but the amount of changes was small. The texture of radish Kimchi was affected by contents of pectic subsrances, especially protopectin. The coefficient of correlation between hardness and protopectin contents was 0.85.(=r)

• Food Science of Animal Resources
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• v.21 no.1
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• pp.38-46
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• 2001

This study was carried out to develop the processed cheese with the increase of unsaturated fatty acid by substituting different vegetable oils for the improvement of nutritional aspects without reducing its sensory advantage and texture properties. The texture properties(hardness, elasticity, adhesiveness, cohesiveness, brittleness and gumminess), meltability, fat leakage degree and sensory evaluation of the processed cheese were analyzed and compared. The meltability of the processed cheese was measured in the range from 59.7 to 138.3mm, the sample substituted with corn oil showed the lowest meltability but the sample substituted with butter resulted in the highest meltability. The degree of fat leakage had the range from 8.28 to 14.71$\textrm{cm}^2$. The sample substituted with safflower oil showed the lowest fat leakage degree but the sample substituted with butter had the highest fat leakage degree. The sample substituted with butter had the lowest hardness. There was no significant difference in the elasticity between the samples tested. The sample substituted with butter showed the lowest value in adhesiveness, cohesiveness, brittleness and gumminess, respectively. The preference score of the processed cheese samples ranged from 3.22 to 6.59. The texture score ranged from 3.12 to 3.26.

• Polymer(Korea)
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• v.39 no.3
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• pp.382-387
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• 2015

The dispersion of calcium carbonate ($CaCO_3$) in polypropylene (PP) and the effect of $CaCO_3$ size on the crystallinity of PP were studied. Polymer composite usually suffers from the brittleness when reinforced with inorganic fillers. The problem is generally related to the size and dispersion of fillers. First, the dispersion was studied for the nanosize $CaCO_3$ with 15~40 nm average diameter. To enhance the dispersibility in PP, the surface of the $CaCO_3$ was treated with sodium lignosulfonate (SLS). $CaCO_3$/PP composites were prepared via melt compounding. The $CaCO_3$ coated with more than 3 wt% SLS was uniformly distributed within the PP matrix, while the uncoated $CaCO_3$ formed aggregated structures in the PP. Even with 30 wt%, the SLS-$CaCO_3$ was well dispersed in the PP matrix. Also, the transition enthalpy of $CaCO_3$/PP increased and the full-width of half maximum of the crystallization peak decreased regardless of SLS coating and size of $CaCO_3$. However, the crystallinity of PP was more influenced by nano $CaCO_3$. These results imply that the nano $CaCO_3$ coated with SLS may reduce the brittleness of polymer composites.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.4
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• pp.345-352
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• 2017

In this study, the effect of cryogenic liquefied natural gas leakage and loading on liquefied natural gas cargo hold is investigated to observe the performance of the polymer foam material that comprises the cryogenic insulation of the cargo hold. The primary barriers of liquefied natural gas carrier that are in contact with the liquefied natural gas will leak if damage is accumulated, owing to fluid impact loads or liquefied natural gas loading / unloading over a long period. The leakage of the cryogenic fluid affects the interior of the polymer foam, which is a porous closed cell structure, and causes a change in behavior with respect to the working load. In this study, mechanical properties of polyisocyanurate foam specimen, which is a polymer material used as insulation, are evaluated. The performance of the specimens, owing to the cold brittleness and the impregnation effects of the cryogenic fluids, are quantitatively compared and analyzed.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.974-980
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• 2008

The principal objective of this study was to assess the sensory quality, degree of gelatinization, color, texture and moisture content of Paeksulgis to which barley was added. The results were as follows: The moisture contents were approximately $35{\sim}39%$. In terms of the Hunter's color values of Paeksulgis of the control, the lightness (L) was 87.63, redness (a) was -1.07, and yellowness (b) was 5.06. The L-value of the control group was high, at 87.63; the L-values of the A1, A2, and A3 groups were 85.97, 83.74, and 83.56, respectively. As the quantity of barley increased, the L-value of the Paeksulgis decreased. The gelatinization of Paeksulgis to which barley was added decreased most profoundly in the A3 group. In terms of sensory quality, Paeksulgis with 10% added barley evidenced the most favorable sensory qualities. In terms of the mechanical characteristics of Paeksulgis, cohesiveness was the highest in the control group, while springiness, gumminess, and brittleness were the lowest. Springiness, and brittleness were decreased reduced with increases in the amount of added barley powder. Brittleness was increased by increases in the amount of added barley powder.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.368-369
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• 2003

선진 복합재료의 매트릭스 수지로서 자장 많이 사용되고 있는 에폭시는 수지 및 경화제의 종류에 따라 여러 가지 물성을 나타낼 수 있다. 에폭시 수지는 기계적 물성 및 내화학성이 우수하고 경화시 수축변형이 적은 장점이 있으나 높은 가친밀도 때문에 순간적인 충격에 취약하다는 단점을 지니고 있다. 따라서 이러한 에폭시 수지의 취성 (brittleness)을 개선하기 위해 충격강도를 증가시킬 수 있는 강인화제를 혼합하여 경화시키는 방법이 사용되고 있다[1]. (중략)