• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.60-66
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• 2011

In this paper, the computer simulation analyzed the effective plastic strain and temperature behaviors. The quantitative analyses which proposed the effective mold design of S/CAM shaft was executed. The parameters of forging shape that affected on the optimize conditions that was calculated with simple equation were investigated. it is expected that the developed analysis model and design technique would greatly contribute to the drum brake optimal design considering effective plastic strain and temperature affected behaviors. This development could save more than 20% of production cost and reduced failure rate to more than 30%. By improving the life span of mold from 15,000 to 25,000, financial difficulty of company imposed on a mold manufacture could be overcome.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.102-106
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• 1999

One of the main causes of unwanted dimensional changes in precision metal mold casting parts is excessive and irregular residual stresses induced by temperature gradients and plastic deformation in the solidifying shell. Residual stresses can also cause stress cracking and lower the fatigue life and fracture strength of the casting parts,. In the present study aluminum alloy casting system with metal mold equipped with electrical heating elements and water cooling units was designed and the casting specimens were produced to quantify the effects of different cooling conditions on the development of residual stresses. the layer removal method was used to measure the biaxial residual stresses in casting specimens produced from the experiments. The experimental results agreed with Tien-Richmond's theoretical model for thermal stress development for the solidifying metal plate

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1113-1118
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• 2008

In the hot forging process, The forging defects that are caused by metal were strain, temperate, and inclusion. In this paper, the computer simulation analyzed the effective plastic strain and temperature behaviors. The quantitative analyses which proposed the effective mold design of S/CAM shaft was executed. The parameters of forging shape that affected on the optimize conditions that was calculated with simple equation were investigated. it is expected that the developed analysis model and design technique would greatly contribute to the drum brake optimal design considering temperature affected and material behaviors. This development could save more than 20% of production cost and reduced failure rate to more than 30%. By improving the life span of mold from 15,000 to 25,000, financial difficulty of company imposed on a mold manufacture could be overcome.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.355-360
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• 2000

Recently, to be satisfied the consumer's demand the life cycle and the lead time of product is to be shorted. So it is important to reduce the time and cost in manufacturing prototypal mold. These days, in order to reduce the lead time and cost high speed machining is highlighted. In the paper, using the high speed machining and aluminum-7075, the fundamental experiment is implemented in the change of cutting force, machining time, surface characteristic according to the tool path. And then the prototypal mold of the automatic knob is machined.

• Design & Manufacturing
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• v.17 no.1
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• pp.13-19
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• 2023

Blanking processing is one of the shear processing method in which the cut part becomes a product and piercing processing is a press molding process in which the cut part is discarded as a scrap. The shear angle of the punch used for blanking is determined by conditions such as the characteristics of the shear material, shear thickness and shear length. The shear angle of a punch is an important factor in determining the size of the shear load, the life of the shear punch, the deformation of the shear product and the quality of burrs In this study, blanking punches applied with four types of shear angles (i.e., 0°, 0°23", 0°46", 0°69") to the blanking punches of bracket products used in practical work were manufactured and tested. In the blanking experiment, the remaining variables except for the shear angle were the same. Experiments show that the product has the least amount of deformation in blanking punches with a shear angle equal to the material thickness, i.e., 0°46"..

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.49-59
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• 2004

This study was carried out to obtain the basic data for producing higher functional coating agents for pulp mold by evaluating various kinds of starch derivatives. At that time, four kinds of starch derivatives were manufactured for making coating agents respectively. Physical properties of coated paperboards were tested. Conclusions obtained from this results were as follows. The water and oil resistance of hydroxypropylated, cyanoethylated and carboxymethy­lated starch were high when degree of molar substitution(DS) of propylene oxide, acrylonitrile and sodium monochloroacetate were 0.18, 0.07 and 0.009, respectively. Also, the those of crosslinked starch were high when degree of crosslinking of epichlorohydrin was 0.02. Consequently, $8\%$ solution of carboxymethylated starch made with DS 0.009 of monochloroacetate was the best among coating agents from starch derivatives men­tioned above.

• Journal of Life Science
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• v.8 no.1
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• pp.1-7
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• 1998

The mold YH-69 producing pigments was isolated from soil, and identified as Monascus sp.. For the production of the pigments from the mold, the best condition was observed with 6% rice powder with 200 mesh, 0.2% yeast extract, 0.3% ammonium sulfate, and 0.02% ZnSO4 at pH 5 and 30$\circ$ for 6 day with reciprocal shaking.

• Journal of Life Science
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• v.11 no.3
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• pp.242-247
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• 2001

Botrytis cinerea E12 was isolated from the leaves, flowers and fruits of eggplant in the greenhouse in Halrim, Kimhae and Dejeo, Pusan. The leaves infected with the pathogen were appeared initially brown-color, small gray spots at the edge, and finally fall down. The fruit was showed the symptoms of circular or irregular shapes, followed by sunken. When the symptoms were developed, the conidia formed on the surface with gray color. To determine the pathogenicity of B. cinerea E12 against the eggplants, the conidia were suspended with 30% tomato juice, PDB and sterile water, respectively. The result showed that the conidial suspension with 30% tomato juice was highly effective on the pathogenicity as more than 90%. Moreover, the symptoms caused by inoculum were the same as those of wild-type pathogen.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.188.1-188
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• 2003

To examine the effect of vacuum packaging on the quality of chicken during storage, microbial (total bacterial counts, mold and yeast, E. coli, and Pseudomonas) changes and drip loss were determined. fresh chicken breasts were prepared and packaged using polyethylene film under vacuum and normal atmosphere, respectively. Samples were then stored at 4$^{\circ}C$ for two weeks. At various time intervals during storage, sample was taken homogenized, and diluted with 0.1% sterile peptone water, and followed by microbial counts. Microbial changes of total bacterial counts, mold and yeast, E. coli, and Pseudomonas during storage of chicken were significantly decreased by vacuum packaging. Drip loss was also significantly decreased. These results indicate that vacuum packaging of chicken should be recommended as a suitable storage method in terms of microbial safety as well as quality of chicken.

• Horticultural Science & Technology
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• v.34 no.4
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• pp.626-633
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• 2016

The objective of this study was to assess the effect of precooling and application of gaseous $ClO_2$ on the retention of freshness and quality of 'Maehyang' strawberry fruits intended for export. 'Maehyang' strawberry fruits (Fragaria ${\times}$ ananassa Duch.) were grown in commercial greenhouses and then harvested. Fruits of uniform and medium size at 60% ripeness were selected and assigned to one of four treatment groups: non-treatment (control), precooling only (PO), gaseous $ClO_2$ only (GCO) or precooling combined with gaseous $ClO_2$ (P + C). Weight loss was lowest in the PO treatment and greatest in the GCO treatment after export. Compared to the control and PO treatment groups, strawberry fruits in the GCO treatment group maintained high brightness and high chroma. Six days after shipping, fruits in the P + C treatment group had the highest soluble solids content, even as high as $10.05^{\circ}Brix$; the lowest value was observed in the PO treatment. The incidence rate of gray mold in strawberry fruits was 20% and 17% in the control and the PO treatment, respectively; in the GCO treatment, the incidence rate of gray mold amounted to 10%. No gray mold was observed in the P + C treatment group. These results indicate that gaseous $ClO_2$ treatment combined with precooling (P + C) was effective in maintaining the freshness of 'Maehyang' strawberry fruits intended for export from South Korea to Hong Kong.