• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.353-360
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• 1992

This study was carried out to investigate the changes of quality in yogurt during delivery and storage. To do this, microbiological, physico-chemical and sensory properties in stirred yogurt were studied at different temperatures $(10^{\circ}C$ & $20^{\circ}C)$ and shakings (100 rpm & 200 rpm for 30 min). Titratable acidity and TCA soluble nitrogen in yogurt were increased in accordance with increase of temperature and time, while pH, lactose and lactic acid bacteria tended to be decreased. Interestingly enough, shaking conditions almost did not influence these studies. In sensory evaluation it showed that acidity was strong and sweetness was weak as increasing the storage temperature and time, but there were no significant differences until 10 days at $10^{\circ}C$ and 3 days at $20^{\circ}C$. Off-flavor was developed after 12 days at $10^{\circ}C$ with only 200 rpm shaking and after 6 days at $20^{\circ}C$ in both shaking conditions. These yogurts were not suitable for consumer. Viscosity in the yogurt became high as the temperature and time were increased. Viscosity was lower in yogurt shaked at 200 rpm than in non-shaked yogurt. Finally, this study indicates that temperature and shaking during delivery of yogurt may be critical in keeping quality of yogurt.

• Korean Journal of Food Science and Technology
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• v.6 no.2
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• pp.109-115
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• 1974

Milssal is a polished, partially gelatinized pressed wheat grain and it is being consumed in Korea. This study was conducted to establish 2 practical means of providing needed lysine to the Korean population through fortification of Milssal. The results are summarized as follow: Lysine infusion of Milssal was significantly higher than polished wheat grain and affected by such factors as time and concentration of infusion solution. Cooking characteristics including water-uptake ratio and expanded volume were apparently better than polished wheat. After conducting the series of fortification experiments under actual manufacturing conditions. a reasonable process was chosen. In the developed process. lysine HCl solution was sprayed instead of water to the cleaned and debranned wheat grains during the regular wetting process. There was no differences in appearance and taste of Milssal before and after fortification. Fortification of the protein of Milssal with lysine has been found to bring a significant improvement in the growth rate of rats and the protein efficiency ratio. Stability remained relatively high throughout the storage period(90 days at $10{\sim}20^{\circ}C$ or 30 days at $37^{\circ}C$).

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.401-406
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• 2010

This study was conducted to investigate the control effects of the environmental-friendly materials against major diseases of pear and to elucidate factors related to spore disperse of pear scab and pear rust. Spore disperse was deeply related ambient temperature in the early stage of disease occurrence and the maximum spore disperse was affected greatly by the air humidity, Percent of infected leaves of pear scab in plot treated with Trichoderma harzianum-YC459 was 29.3% and 43.3% in plot treated with Sulfur-80%. Two formulations above-mentioned were less effective to control pear scab than the chemical pesticide, hexaconazole. Control effect in plots single- and mixed-treated with Trichoderma harzianum-YC459, Sulfur-80% and hexaconazole against pear scab were compared with that in plot treated with chemicals by conventional application schedule in pear orchard. The incidence of pear scab was lower in plot treated with the environmental-friendly materials than that of untreated plot. However there was no significant difference among the treatments at the 5% level. Application of Sulfur-80% reduced significantly the incidence of pear scab (7.8%) compared to that (10.3%) in plot treated by conventional application schedule in organically cultivated pear orchard. Alternative application of Trichoderma harzianum-YC459 and Sulfur-80% (4.3%) suppressed the incidence of pear rust than that (7.1%) in plot treated by conventional application schedule in organically cultivated pear orchard.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.661-666
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• 2003

This research was aimed at evaluating the effects of natural antioxidants on lipid oxidation and sensory quality in cooked, chill- stored and reheated Wanjajun prepared with pork meat (short shank). Sage (SA) and combinations of herbs; basil/mints (BM), rosemary/parsley/thyme (RPT) were used as sources of antioxidants. The products were pan-fried in a medium layer of soybean oil and then stored in a refrigerator at 3$^{\circ}C$ for 8 days after rapid chilling. The process of heat treatment of Wanjajun caused changes in the chemical composition of products and simultaneously, thermal oxidative reaction was initiated. During storage of products in a refrigerator, further hydrolytic and oxidative processes in the lipid extraction were progressed. Acid value was increased, peroxides and malonaldehyde formation gradually were increased during cool storage. Addition of garlic, sage and combinations of herbs retarded the process of oxidation. Wanjajun made with addition of SA and RPT showed good quality in antioxidative potential after 8 days of storage. The sensory effect of herbs on undesirable warmed-over flavor was in order of : SA>RPT>BM.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.16-26
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• 2017

In chemical industry plants, the raw material, intermediate and final products can leak from unstable joints of flanges and valves as well as cracks of storage tanks. From the safety and economic standpoints, it is very important to understand whether leaks or not and leakage rate. The OGI(optical gas image) technique can tell gas leakages, but cannot give the leakage rate. Some special OGI devices can show the kind of gas in different color concentration in different darkness. Therefore the research on quantification of OGI is necessary. In this research, we have developed the practical method to quantify OGI of methane leakage. To estimate 3-dimensional gas leakages distribution from 2-dimensional OGI, the Monte Carlo Probability technique was applied. First the number of points in the area of width(2.54 cm) and length(2.54 cm) in OGI was counted. Total no of each experiment was compared with the measured flow rate. The correlation average between total points and measured flow rate was found to be 0.980. Reversely we estimated the leakage rate of OGI by use of the correlation table. The results showed good agreement between the estimation value and the measured value.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1411-1417
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• 2010

CFRP (Carbon Fiber Reinforced Plastic) has received considerable attention in various fields as a structural material, because of its high specific strength, high specific stiffness, excellent design flexibility, favorable chemical properties, etc. Most products consisting of several parts are generally assembled by mechanical joining methods (using rivets, bolts, pins, etc.). Holes must be drilled in the parts to be joined, and the strength of the components subjected to static and fatigue loads caused by stress concentration must be decreased. In this study, we experimentally evaluated the variation in the residual strength of a holenotched CFRP plate subjected to fatigue load. We repeatedly subjected the hole-notched specimen to fatigue load for a certain number of cycles, and then we investigated the residual strength of the hole-notched specimen by performing the fracture test. From the results of the test, we can observe the initiation of a directional crack caused by the applied fatigue load. Further, we observed that the residual strength increases with a decrease in the notch effect due to this crack. It was evaluated that the residual strength increases to a certain level and subsequently decreases. This variation in the residual strength was represented by a simple equation by using a model of the decrease in residual strength for plain plate, which was developed by Reifsnider and a stress redistribution model for hole-notched plate, which was developed by Yip.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.5
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• pp.543-547
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• 2015

The cooling process referred to as Tempcore has been applied to produce a high-strength rebar. Excellent rebar with strength and weldability can be manufactured from mild steel without the addition of alloying elements by using the Tempcore process. However, there are limitations to evaluating the effect of various chemical compositions and cooling conditions within a site facility. In this study, we developed an apparatus to simulate the Tempcore process and obtained microstructures with a hardened surface layer, an intermediate region and a soft inner core. The experimental apparatus has been equipped with a cooler set that is the same as the site facility and consists of a pump line that supplies pressure of 12-13 bar and flow rate of up to $50m^3/h$. In accordance with the simulation result of steel grade SD400 that requires more than 400 MPa of yield strength, both the hardened area ratio and the hardness with respect to each cooling depth were found to agree well with the product.

• Journal of the Korean Wood Science and Technology
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• v.41 no.4
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• pp.346-357
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• 2013

In this study, it was conducted to produce wood pellets using domestic forest thinning residues and examine their quality according to Korean pellet quality standard. Raw materials were composed of larch and mixed broad leaves species. Based on the small-end diameter (6 cm), they were classified into four different types of raw materials such as LM (larch with middle diameter), LS (larch with small diameter), MM (mixed broadleaf with middle diameter), and MS (mixed broadleaf with small diameter). After crushing and drying process, wood pellets were produced by a ring-die type pelletizer using each raw material. Wood pellets made from four different types of raw materials were tested for their quality such as calorific value, moisture content, ash content, inorganic matters and so on. As results of quality analysis, the calorific values of all wood pellets were higher than 198 kcal/kg, and satisfied with the first grade of Korea wood pellet standard. The ash content was slightly increased after pelletizing. Mechanical durability of wood pellets was highly dependent on the types of raw materials. The quality differences among wood pellets were turned out due to different physical and chemical characteristics of raw materials even though the same pelletizing condition was applied.

• The Korean Journal of Pesticide Science
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• v.8 no.2
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• pp.103-106
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• 2004

To confirm physico-chemical stability of formulated products, this study was conducted under different storage conditions; room temperature and accelerated temperature of $54^{\circ}C$. The tested pesticide formulations were dichlorvos 50% EC, acephate 50% WP, hymexazol 4% DP, thiram 80% WP and isoprothiolane 12% GR. The selected formulations were stored for 10 weeks and 5 years under the given temperature in maximum and contents of active ingredients were also analyzed by GLC or HPLC after each time of storage. The degradation rates of 5 active ingredients under the two conditions showed a similar trend except acephate. Acephate was rapidly decomposed at $54^{\circ}C$ but slowly decomposed at room temperature, and the degradation rate under the accelerated condition was 2.4 to 5-fold higher than that under the room temperature. Consequently, the stability test on active ingredients in pesticide formulations was able to recommend to be carried out under the accelerated condition except acephate. And the physical properties of all formulations tested under two storage conditions were good.

• Journal of Food Hygiene and Safety
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• v.23 no.3
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• pp.182-190
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• 2008

A survey on consumer's awareness and perception toward genetically-modified(GM) foods was conducted on 2110 random samples of Korean consumers. More than 65% of the respondents were exposed to some information related to GM foods. The respondents answered that the greatest benefit of the development of GM foods is remedy of potential food shortages in the future. More than 90% of Korean consumers wanted GM foods to be labeled as such. More than 50% of the respondents would not buy until they know more about GM foods. Only 35.8% of Korean consumers were found to know that food items originating from plants contained genes. More consumers responded that they would not buy herbicide-resistant GM soybean but buy vitamin-enriched GM soybean. Many Korean consumers' decision of acceptance or rejection of GM foods depend not on the basis of biotechnology, but on the basis of the degree of benefit to the consumers. Only 6.4% of Korean consumers responded that GM foods were the greatest threat to the safety of Korean foods. The perception of Korean consumers on GM foods has not changed significantly during the past 5 years.