• Journal of Energy Engineering
• /
• v.25 no.3
• /
• pp.18-26
• /
• 2016

Mineral oil is the most widely used for electrical transformer, though some factors should be considered such as their environmentally harmfulness when it spill and low flash point. To cover these disadvantages, vegetable oil has developed because of its high biodegradability and thermal stability. However, it is necessary that many studies should conduct to reveal the detailed impacts of long-term operation as transformer oil. In this paper, we applied the accelerated aging test which simulate the real transformer circumstances using insulation paper, coil, steel at $150^{\circ}C$, which is higher than normal operation, for 2 weeks. To figure out the oxidation characteristics between mineral oil and vegetable oil test major properties and components such as total acid number, dielectric breakdown and dissolved gas components during that period. As a result of these tests, we found that vegetable oil has higher electric insulation ability than mineral oil though poor total acid number by hydrophile property. Vegetable oil also kept its thermal stability under the given circumstances.

• Journal of Plant Biotechnology
• /
• v.30 no.1
• /
• pp.35-40
• /
• 2003

In this study we investigated the effect of gametocides on the number of larger-sized pollen in anther, and also induced callus from the anther culture of Zoysia japonica Steud. Before culturing, we have observed pollens in anther through fluorescence and electron microscopes to know pollen dimorphism. There were two types of pollens observed. One type (30-36 ${\mu}{\textrm}{m}$ in diameter) consisted of vacuolated, larger-sized pollens and the other (15-20 ${\mu}{\textrm}{m}$ in diameter) smaller-sized ones with dense cytoplasm and plenty of amyloplasts. Within few hours, all the smaller-sized pollens were dead, while larger-sized ones were viable for one or two days. To induct larger-sized pollens, various gametocides were leaf-sprayed on three booting stages cultured under 4$0^{\circ}C$ /15$^{\circ}C$ (day/night) before anther culturing. Number of these larger pollens were few (less than 1%) in anther without spraying gametocides. GA$_3$increased the number of larger-sized pollens when applied at mid-booting stage. GA$_3$ with 50 mg/L treatment caused the highest percentage (25.4%) of the larger-sized pollen. Anthers with GA$_3$ treatment were only produced calli on AA medium (modified B$_{5}$+8.0 mg/L 2,4-D ＋0.2 mg/L kinetin), but callus formation was quite low (less than 1%).).

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.37 no.2
• /
• pp.85-94
• /
• 2001

The vertical distribution and activity patterns of fishes during the evening and morning transitions were investigated acoustically and by pelagic trawling on October 2-10, 1997 in the Korean Eastern Sea. The acoustic data were collected from four stations with a scientific echo sounder operating at a frequency of 38 kHz, and the echogram was used to analyze the diel vertical migration of fish. Biological sampling was accomplished by pelagic trawling to identify fish species recorded on the echograms, and the species and length compositions were investigated. Vertical profiles of water temperature, salinity at the trawl station were taken with a CTD system and were related to the diel movement and the depth distribution of fish. During the day, one group of fish mainly distributed above the depth layer of 50 m, the other group was at deeper water, approximately 250 m, but began to migrate toward the surface before sunset with a time difference. During the night, they were dispersed between the surface and the depth of 125 m. Just prior to sunrise, the scattering layer was divided with 2 groups and began to migrate downwards, respectively. Several trials of pelagic trawling for scattering layers suggest that the most dominant scatterer in the survey area of this study was Japanese flying squid, Todarodes pacificus..

• Korean Journal of Food Science and Technology
• /
• v.17 no.3
• /
• pp.155-162
• /
• 1985

The sugers and free amino acids of honey(Western and Domestic honey) and the changes of diastase activity during storage at various temperatures and HMF were studied. The average content of sugers in the western honey was 40.20% of fructose, 32.43% of glucose and 1.0% of sucrose. The average ratio of fructose to glucose was 1.24. In the case of the domestic honey, average content of sugers was 37.37% of fructose, 31.92% of glucose and 0.74% of sucrose and the average ratio of fructose to glucose was 1.19. Of the 16 amino acids detected, proline was the most predominant free amino acid in all of the honey studied, representing 39.59 to 46.86% of total free amino acids. Diastase activity of honey during the storage at $50^{\circ}C$ was rapidly decreased, but it was notably changed during storage at low temperature ($4^{\circ}C$) and room temperature ($20^{\circ}C$). The accumlated content of HMF were 0.12 to 0.47mg% during storage at 80 days at $20^{\circ}C$ and 5.35 to 8.71mg% after 3 weeks storage at $50^{\circ}C$.

• Korean Journal of Food Science and Technology
• /
• v.43 no.3
• /
• pp.271-276
• /
• 2011

Volatile profiles of beverages and encapsulated powders containing Artemisia princeps Pampan extracts were analyzed by solid-phase microextraction-gas chromatography/mass spectrometry during production and storage. Beverages containing 0.32 and 0.64% extracts were stored at room temperature for 8 weeks and $60^{\circ}C$ for 8 days, respectively. Encapsulated particles were stored at room temperature and $60^{\circ}C$ for 8 days. Total volatiles in beverages decreased significantly during storage, irrespective of storage condition (p<0.05). Terpenoids, including cymene, thujone, and ${\beta}$-myrcene, were major volatiles in beverages, and some volatiles including ethylfuran, vinylfuran, and 2-fufural increased in 60oC samples only. Total volatiles in microcapsules at room temperature were not significant different for 8 days (p>0.05), whereas those at $60^{\circ}C$ increased by 16.5 times. Limonene was the most detected volatile in microcapsules, and aldehydes such as hexanal, pentanal, and octanal, and furans such as 2-butylfuran and 2-pentylfuran increased in the $60^{\circ}C$ samples, which may have originated from oxidized lipids used in the microcapsules.

• Food Science of Animal Resources
• /
• v.22 no.1
• /
• pp.8-12
• /
• 2002

This study was conducted to investigate the influence of dietary sardine oil on storage and processing characteristics in meat sample of chicken meat. Broilers were randomly assigned to one of four dietary treatments: 1) Control(commercial feed) 2) T1(commercial feed supplemented with 1% sardine oil) 3) T2(commercial feed with 2% sardine oil) and 4) T3(commercial feed with 4% sardine oil). They were fed one of the experimental diets for five weeks and slaughtered. After that, the meat samples were vacuum packaged and stored at 4$\pm$1$\^{C}$. The storage and processing characteristics were analyzed for meat samples stored over a period of 0, 1, 3, 7 and 10 days. The pH of all treatments significantly increased during the storage periods (p<0.05). The TBARS(thiobarbituric acid reactive substances) af all treatments were significantly increased as storage period extended (p<0.05). After 1 days, the TBARS of treatment groups were significantly higher than that of the control (p<0.05). The T3 showed the highest TBARS among all treatments (p<0.05). The VBN(volatile basic nitrogen) of all treatments significantly increased during storage period (p<0.05). However, the VBN was not significantly different between control and treatment groups. The WHC(water holding capacity) and heating loss were significantly increased in both control and treatment groups during storage (p<0.05) and however, WHC was not significantly different among 3 treatment. The heating loss tended to increase in treatment groups compared to the control.

• Food Science of Animal Resources
• /
• v.22 no.1
• /
• pp.37-43
• /
• 2002

This study was conducted to investigate the influence of dietary activated carbon(0.9%) and sardine oil (0, 1, 2, 4%) on volatile basic nitrogen(VBN), thiobarbituric acid reactive substance(TBARS), and fatty acid in meat sample of chicken. Broilers were randomly assigned to one of the file dietary treatments: 1) Control(commercial feed) 2) T1(commercial feed supplemented with 0.9% activated carbon) 3) T2(commercial feed with 0.9% activated carbon and 1% sardine oil) 4) T3(commercial feed with 0.9% activated carbon and 2% sardine oil) 4) T4(commercial feed with 0.9% activated carbon and 4% sardine oil). They were fed one of the experimental diets for five weeks and slaughtered. After that, the meat samples were stored over a period of 0, 1, 3, 7 and 10 days at 4${\pm}$1$^{\circ}C$. The VBN of all treatments significantly increased during the storage periods(p<0.05). Also, the VBN was not significantly between control and treatment group. In VBN of breast was higher compared with that of thigh. The TBARS of all treatments were significantly increased as storage period extended (p<0.05). The TBARS of control and thigh tended to be higher than that of treatments and breast. Oleic acid, palmitic acid, linoleic acid, stearic acid were major fatty acid in chicken meat. Saturated fatty acid decreased and unsaturated fatty acid increased of all treatments during storage. Oleic acid, EPA, DHA contents was higher in treatment group than the control.

• Korean Journal of Food Science and Technology
• /
• v.12 no.4
• /
• pp.278-284
• /
• 1980

Lipids from rice bran (Indica type Milyang #23), both fresh and stored at $30^{\circ}C$ and 80% relative humidity for 5 weeks, were separated and analyzed for the determination and the storage effect on the bran lipid composition. Total lipids of fresh rice bran consisted of 89.9% neutral lipids, 8.0% glycolipids, 2.1% phospholipids and no significant changes of these fractions were noted during storage. Triglycerides(43.1%), diglycerides(13.8%) and hydrocarbon-esterified sterol(13.5%) among six fractions were considered as main components in neutral lipids. After storage triglycerides content significantly decreased as the free fatty acid increased in the neutral lipid fraction. Major components of the glycolipid fraction were acylsterolglycoside(43.1%) and sterolglycoside(30.3%). Phosphatidyl choline(39.8%), phosphatidyl serine(20.9%) and phosphatidyl ethanolamine(19.8%) were predominent in the phospholipid fraction. No significant changes of the composition were shown in fraction of the glycolipid or the phospholipid during the storage period. Major fatty acids of the total lipid fraction were oleic(44.3%), linoleic(32.5%) and palmitic acids(18.4%). The fatty acid compositions of the neutral lipid, the glycolipid and the phospholipid fractions were similar to the total lipid fraction. Small changes in fatty acid composition in each fraction were noted during the storage period. The acid value increased but iodine value decreased during the storage period. The values of peroxide and TBA increased gradually in the first three weeks, and then slowly decreased in the fourth and the fifth week of the storage.

• Journal of Bio-Environment Control
• /
• v.29 no.3
• /
• pp.265-276
• /
• 2020

This study was conducted to provide a basis for raising farm income by increasing the yield and extending the cultivation period by creating an environment where crops can be cultivated normally during high temperatures in summer. The maximum cooling load of the multi-span greenhouse with a floor area of 504 ㎡ was found to be 462,609 W, and keeping the greenhouse under 32℃ without shading the greenhouse at a high temperature, it was necessary to fog spray 471.6 L of water per hour. The automatic fog cooling control device was developed to effectively control the fog device, the flow fan, and the light blocking device constituting the fog cooling system. The fog cooling system showed that the temperature of the greenhouse could be lowered by 6℃ than the outside temperature. The relative humidity of the fog-cooled greenhouse was 40-80% during the day, about 20% higher than that of the control greenhouse, and this increase in relative humidity contributed to the growth of cucumbers. The relative humidity of the fog cooling greenhouse during the day was 40-80%, which was about 20% higher than that of the control greenhouse, and this increase in relative humidity contributed to the growth of cucumbers. The yield of cucumbers in the fog-cooled greenhouse was 1.8 times higher in the single-span greenhouse and two times higher in the multi-span greenhouse compared to the control greenhouse.

• Journal of Bio-Environment Control
• /
• v.29 no.3
• /
• pp.231-238
• /
• 2020

Strawberry (Fragaria × ananassa Duch.), a herbaceous perennial crop, is a popular fruit crop with high economical and nutritive values. This study was conducted to investigate the effect of the runner training angle (RTA) on the length of internodes and number of runners produced in strawberry 'Seolhyang' and 'Maehyang' in an attempt to achieve a higher production rate of runner plants and increase the propagation efficiency. Runners were trained for 30 days to grow at an angle of 0° (vertically upward), 45°, 90° (horizontal), 135°, or 180° (hanging down) from the upward vertical axis. The experiment was carried out in a glasshouse with 29/20℃ day/night temperatures, an average light intensity of 450 μmol·m^-2·s^-1 PPFD coming from the sun, and a natural photoperiod of 12 hours. For both 'Seolhyang' and 'Maehyang', the RTA affected number and length of runners, and number and fresh and dry weights of runner plants. Training at an angle of 135° or 180° shortened length of runners and internodes in 'Seolhyang'. These RTAs also produced runner plants with the lowest fresh and dry weights in both cultivars. The RTA did not affect the runner diameter, but affected the runner morphology in both cultivars. As compared to a RTA of 135°, a 180° RTA increased number of runner plants produced, making it the most proliferative RTA.