• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.45-50
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• 2005

In this study, the casting/forging process was applied in manufacturing a low control arm, in order to prove that application of casting/forging process to Al6061 is likely to get the effect of light weight compared with existing steel products and to reduce the cost of materials. Firstly, In order to set up the optimum casting condition of the forging material, Al6061, casting experiments were carried out by controlling pouring temperature of the aluminum for casting, mold temperature, and pouring time. $700^{\circ}C$ pouring temperature, $300^{\circ}C$ mold temperature and 10-second pouring time were taken into account as the optimum casting conditions. With respect to a hot forging test, it is practiced on the basis of a temperature of materials, strain rate, and reduction rate so as to observe each microstructure and examine strain-stress curve simultaneously; examine tensile test and hardness test; eventually set up the optimum hot forging condition. A hot forging test, tensile test, hardness experiment, and microstructure observation were carried out on condition of $70\%$ reduction rate, $500^{\circ}C$ temperature of materials, and 1 strain rate. As a result of those experiments, 330MPa tensile strength, $16.4\%$ elongation, and 122.8Hv hardness were recorded. In oder to get a sound preform which has no unfitting cavity and less flash, two preforms were proposed on the basis of volume rate of the final product; the optimum volume rate of preform for the low control arm was $115\%$. In conclusion, it is confirmed that using the forging material rather than casting materials in casting/forging process is likely to get more superior mechanical properties. Compared with Al6061, performed by means of general forging, moreover, cast/forged Al6061 can not only stimulate productivity by reducing production processes, but cut down the cost of materials by reusing forging scraps.

• Journal of Food Hygiene and Safety
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• v.32 no.5
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• pp.443-446
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• 2017

This study investigated the physical properties of polymers and antimicrobial activities of organic acids on Listeria monocytogenes to develop hydrogels. ${\kappa}-carrageenan$ (1, 2, and 3%), carboxymethylcellulose (CMC; 1, 3, and 5%), and agar (1.5 and 3%) were mixed with cross-linkers ($Na^+$, $K^+$, $Ca^{2+}$, and $Al^{3+}$) or each other by stirring or heating to form cross-linkage, and their physical properties (hardness, elasticity, and swelling) were measured. The hydrogels formulated with organic acid (1, 3, and 5%) were analyzed by spot assay against L. monocytogenes. ${\kappa}-carrageenan$ formed hydrogels with high hardness without other cross-linkers, but they had low elasticity. The elasticity was improved by mixing with other cross-linkers such as $K^+$ or other polymer, especially in 3% ${\kappa}-carrageenan$. CMC hydrogel was formed by adding cross-linkers $Al^{3+}$, $Na^+$, or $Ca^{2+}$, especially in 5% CMC. Thus, stickiness and swelling for selected hydrogel formulations (two of ${\kappa}-carrageenan$ hydrogels and three of CMC hydrogels) were measured. Among the selected hydrogels, most of them showed appropriate hardness, but only 3% ${\kappa}-carrageenan-contained$ hydrogels maintained their shapes from swelling. Hence, 3% ${\kappa}-carrageenan+0.2%$ KCl and 3% ${\kappa}-carrageenan+1%$ alginate+0.2% KCl+0.2% $CaCl_2$ were selected to be formulated with lactic acid, and showed antilisterial activity. These results indicate that 3% ${\kappa}-carrageenan$ hydrogels formulated with lactic acid can be used to control L. monocytogenes on food surface.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.4
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• pp.370-378
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• 2004

The purpose of this study was to investigate the effect of added nutriprotein and rice powder as a plasticizer on physicohemical property, texture property of Backsulgi. In the physicochemical property, the content of proximate composition of nutriprotein was measured as 6.1% of moisture, 3.6% of carbohydrate, 84.3% of crude protein, 0.6% of crude lipid, 5.4% of ash. The raw material of rice powder was measured as 9.6% of moisture, 83.7% of carbohydrate, 6.0% of crude protein, 0.4% of crude lipid, 0.3% of ash. Swelling power and pore ratio of the control were 78.53% and 72.42%, and tended to increase as the amounts of nutriprotein and plastic rice powder increased. Aging by Avrami eguation retarded in Backsulgi added 10% plastic rice powder than rice powder Backsulgi. All the samples added 2, 4, 6, and 8% nutriprotein at the temperatures of 20 were more effective than others on aging. In texture properties, cohesiveness and springiness were not significantly changed by adding nutriprotein and not significantly changed during the storage period in all samples. Hardness and gumminess decreased by adding 2∼8% nutriprotein and increased during the storage period in all samples. Springiness and gumminess decreased by adding 40% plastic rice powder and increased during the storage period in all sample. Cohesiveness and hardness decreased by the increase of plastic rice powder. The texture characteristics by rheometer showed that Backsulgi with nutriprotein and plastic rice powder exhibited lower in hardness than the control, indicating that nutriprotein and plastic rice powder were effective in retarding retrogradation, which is better when storage time became longer.

• Journal of the Korean Society for Heat Treatment
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• v.29 no.5
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• pp.220-226
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• 2016

The mechanical properties of Ti-6Al-4V can be improved by microstructural control through the heat treatment in ${\alpha}+{\beta}$ region. The heat treatment was carried out with a variety of heat treatment temperatures and holding times to find the optimized heat treatment conditions and it was analyzed by linking the microstructural characteristics and mechanical properties. The part of ${\beta}$ phase with $10{\pm}2wt%$ vanadium was transformed into ${\alpha}^{{\prime}{\prime}}$ martensite phase after quenched, so the hardness and tensile properties were decreased below $900^{\circ}C$. The higher the heat treatment temperature is, the smaller is the vanadium-rich region, which leads to transformation into hcp ${\alpha}^{\prime}$ martensite above $900^{\circ}C$. The hardness and tensile properties were improved due to the hard ${\alpha}^{\prime}$ martensite. As the holding times were longer, the hardness and tensile properties decreased below $900^{\circ}C$ because of the softening effect by the grain growth. When varying the holding times above $900^{\circ}C$, the change of mechanical properties was slight because the softening effect of grain growth and the strengthening effect of ${\alpha}^{\prime}$ phase were counteractive. Therefore, the best conditions of heat treatment, which is in the range of $920{\sim}960^{\circ}C$, 40 min, WQ, can effectively improve the mechanical properties of Ti-6Al-4V.

• Journal of the Korean Society of Food Culture
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• v.26 no.4
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• pp.400-408
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• 2011

This study was performed to analyze the retarded degree of Garaetteok retrogradation added with different ratios 0-15% (w/w) of apple pomace dietary fiber powder (DFP). SEM (${\times}$500) showed that air cell size on the Garaetteok surface increased as DFP content increased, whereas control had a compact structure without air cells. The degrees of Garaetteok retrogradation after 3 days at 4 and 25$^{\circ}C$ by ${\alpha}$-amylase iodine method were 57.44 and 41.55% for control, respectively. On the other hand, those of 15% DFP Garaetteok were 28.38 and 15.05%, respectively. Enthalpy changes (${\Delta}$E) by DSC of control, 10 and 20% DFP Garaetteok after 3 days of storage at 4$^{\circ}C$ were 4.41, 4.17, and 3.80 J/g, respectively, whereas those at 25$^{\circ}C$ were 2.14, 1.04, and 0.72 J/g. Hardness of 15% DFP Garaetteok was around 48% compared to that of control after 3 days of storage at 25$^{\circ}C$. Increasing DFP content from 0 to 15% decreased L color value from 86.2 to 55.1, whereas a and b values increased from -1.9 to 8.9 and from 5.3 to 20.8, respectively. In a sensory intensity test, hardnesses of 15% DEP Garaetteok were significantly different at 1 and 0.1% compared to those of control after production and followed by storage for 3 days at 4$^{\circ}C$, respectively.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.5
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• pp.719-726
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• 2007

The results of adding citrus to Jeungpyun in order to diversify the kinds of Jeungpyun available as well as enhance the usage of citrus fruits, were assessed in this study. During fermentation pH was reduced carbon dioxide development was lowest in the citron product and then the tangerine, cumquat and control Jeungpyun, respectively. Volume and specific volume of Jeungpyun were highest id the cumquat Jeungpyun. For all the citrus additions, except for the cumquat there were no significant differences when compared to the control. The tangerine product showed the highest redness and yellowness among the types of citrus, fellowed by cumquat, citron, and lemon. In the textural property tests, hardness was highest in the lemon Jeungpyun. Then, less hardness occurred in the order of citron, control, tangerine and the cumquat Jeungpyun was the softest. In the sensory evaluation, preferred color was in the order of tangerine, cumquat citron, and lemon Jeungpyun. Ultimately, the tangerine Jeungpyun had the best color. In the taste test, preferred taste was in the order of cumquat, citron, tangerine, and lemon Jeungpyun, all resulting in better taste than the pure Jeungpyun. The softness of the Jeungpyun was good in the order of cumquat, tangerine, control, citron, and lemon Jeungpyun. Thus, the cumquat Jeungpyun was softest, while lemon Jeungpyun was hardest. Finally, overall acceptance was good in the order of cumquat, tangerine, citron, control, and lemon Jeungpyun.

• Korean journal of food and cookery science
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• v.30 no.5
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• pp.620-630
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• 2014

Traditionally, the persimmon Gojongsi (Diospyros kaki Thunb) is peeled to make dried persimmons and the skins are thrown away. In this study, the quality characteristics of cookies containing persimmon peel powder were tested for recycling of the persimmon peels. The amounts of persimmon peel powder added to the cookies were about 0, 5, 7, 9 and 11%. The densities of the cookies of the control group and the persimmon peel powder containing experimental group were 1.25 and 1.25~1.37 respectively. The pH was 6.02 for the control group and 5.95~6.01 for the experimental group. Significant differences in the moisture content were observed between groups at 3.34 and 2.16~3.31 for the control and experimental groups, respectively (p<0.05). The spreadabilities and loss rates of the cookies increased with increasing amounts of persimmon peel powder (p<0.05). In contrast, the loss rates and leavening rate of the cookies decreased significantly with decreasing amounts of persimmon peel powder (p<0.05). The lightness of the cookies showed significant decrease (p<0.05), while the redness and yellowness increased with increasing amounts of persimmon peel powder. The hardness (kg) of the control group was 0.847 while that of the experimental group was 0.904~1.110. In the QDA, the results of sensory characteristic analysis showed that the experimental group earned 11% higher scores for color, flavor, taste, and bitterness, 7% higher for appearance and 9% higher for after taste. The consumer acceptance test revealed the experimental group to have a 7% more positive evaluation for color, favor, taste and texture than the control group. On the grounds of the experiment above, the optimal mixture ratio from the sensory test was found to be 7% persimmon peel powder in the cookies.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.166-174
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• 1998

The effects of some organic acids on the shelf life of cooked noodle and the change in textural properties were studied. Organic acids used were vinegar, lactic, citric and malic acid. The pH of noodle was adjusted to $4.7{\pm}0.25$ by dipping it in each solution for 30 seconds. Total microbial count and turbidity of the treated samples were measured storage for 4 days at $15^{\circ}C$. The total count was high in order of control, malic, citric, lactic acid and vinegar. High turbidity was observed in order of control, lactic, malic, citric acid and vinegar. Hardness, adhesiveness, cohesivenes and springiness were measured for 30 days at $35^{\circ}C$ using Rheometer along with concurrent sensory evaluation. The acid treated samples showed higher values in hardness and cohesiveness than control but lower in adhesiveness and springiness. After 30 days storage, the malic or citric acid treated sample led to a somewhat higher gumminess than control. Based on the sensory evaluation the malic acid treated noodle significantly exhibited the highest score followed by citric, lactic acid, control and vinegar.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.1
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• pp.47-54
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• 2002

This study examined the chemical and sensory characteristics of Altari Dongchimi with inoculation of Leuconostoc citreum IH22. Dongchimi was stored at room temperature for the first day and at 4$^{\circ}C$ from 2nd to 28th day. The pH was somewhat lower in Altari Dongchimi when first inoculated with Leuconostoc citreum IH22 than non -treated Dongchimi. As fermentation proceeded, titratable acidity of Altari Dongchimi significantly increased. The patterns of microflcral changes in both the inoculated and the control were similar during fermentation: the total number of bacteria increased at the beginning, but rapidly decreased right after the optimum ripening point. The hardness and fracturability of both Dongchimi's decreased gradually during fermentation. The evaluation of the sensory qualities showed that the sour taste and fresh taste resulted in similar scores in both Dongchimi's but overall acceptability of the control was higher than that of inoculated one with Leuconostoc citreum IH22.

• Culinary science and hospitality research
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• v.15 no.1
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• pp.94-104
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• 2009

This study examined the quality characteristics of Garaedduk with raw rice bran in addition of the control at 10%,20%,30% & 40% and to measure the mechanical and sensory quality characteristics in order to show the optimum addition ratio and production condition. As a result of supplement of raw rice bran with 10% up to 40% in all research groups, we have founded out as follows. First of all, moisture content decreased and the "L" score which represents the brightness of Garaedduk showed 68.89 in the control which was non supplemented Garaedduk. L-value decreased. However, a-value increased significantly and b-value increased except in the control group. In the experiment on hardness, it showed 0.69 in the control group and 0.92 in Garaedduk supplemented 10% of raw rice bran. Also, there was significant difference in hardness depending on supplement amount of rice bran and storage period. In the experiment on sensory evaluation of color and flavor in the panel test, all supplement groups showed higher scores than the control group. Also, there was significant difference in the taste depending on the amount of raw rice bran. As a test result, the overall acceptability by sensory evaluation was observed as 20%>10%>40%>30%> in the raw rice bran supplement group.