• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.768-776
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• 2015

This study was performed to understand combustion properties four major Indonesian wood species such as Albizia, Gmelina, Mangium and Mindi were investigated by cone-calorimeter for better utilization of theses wood species. Heat release rate (HRR), total heat release (TSR), specific mass loss rate (SMLR), effective heat of combustion (EHC), time to ignition (TTI), flame time (FT), specific extinction area (SEA), smoke production rate (SPR) and CO compound production rate were measured. HRR, THR and FT were proportional to the density of woods. Albizia showed the highest HRR, while Mindi had the lowest HRR. For SPR, Albizia showed the highest value due to its higher SEA. On the other hand, Mindi had the lowest SPR due to a lower SEA value. The highest smoke emission was for Albizia at the beginning of combustion. After 300 seconds, smoke emission of Gmleina and Mangium was increased greatly. Mangium and Mindi showed the highest total carbon dioxide emission. Expecially, Gmelina released the highest carbon monoxide during the combustion period and presented three times higher $CO/CO_2$ ratio than those of other species due to incomplete combustion.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.8
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• pp.401-406
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• 2020

NOx (nitrogen oxide) in the exhaust gas engines causes severe air pollution. NOx is produced under high-temperature combustion conditions. EGR (exhaust gas recirculation) is normally used to reduce the combustion temperature and NOx production. As the EGR ratio increases, the NOx level becomes low. On the other hand, an excessively high EGR ratio makes the combustion unstable resulting in other air pollution problems, such as unburned hydrocarbon and higher CO levels. In this study, the improvement of fuel droplets moving by the radiation of sonic waves was studied for the stable combustion using analytic and experimental methods. For the analytical study, the effects of the radiation of a sonic wave on the fuel droplet velocity were studied using Fluent software. The results showed that the small droplet velocity increased more under high-frequency sonic wave conditions, and the large droplet velocity increased more under low-frequency sonic wave conditions. For the experimental study, the combustion chamber was made to measure the combustion pressure under the sonic wave effect. The measured pressure was used to calculate the heat release rate in the combustion chamber. With the heat release rate data, the heat release rate increased during the initial combustion process under low-frequency sonic wave conditions.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.310-316
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• 1999

In the traumatized teeth, the major complications are pulp necrosis, and root resorption. The factors influencing to prognosis are the state of root development, type of injuries, quality of fixation. There are good prognosis in the case of immature teeth, minor luxation injuries. To minimize of occurrence of these complication, it is very important to determine the pulp vitality. This can help us decide whether or not to treat the teeth endodontically. But, it is difficult to determine of pulp vitality in immature teeth or traumatized teeth. In this case, pulp vitality test was done periodically on the traumatized upper central incisors, and the results were different among cold test, electric pulp test, and laser Doppler flowmetry. The conclusions were obtained from this case can be summarized as follows; 1. Pulp vitality of traumatized teeth should be negative early, but with time going, pulp vitality could be recovered. 2. The positive response of pulp vitality test was detected earlier in laser Doppler flowmetry. 3. Between cold test and electric pulp test, cold test was more reliable in determining pulp vitality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.434-439
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• 1989

This study was carried out to investigate the minimum days for raising infant rice seedling with different temperature (day/night $^{\circ}C$ : 20/12, 25/18, 30/20) and to compare with seedling growth and rooting ability at 10 days after transplanting with endosperm-intacted and removed seedlings. The minimum days for raising infant rice seedling was shown differently with different temperatures, thus there were turned out by mat formation to be 10 days at 20/12$^{\circ}C$ (day/night), 8 days at 25/18$^{\circ}C$ and 6 days at 30/20$^{\circ}C$, respectively. Seedling height, leaf number and dry weight of top part at the minimum days for raising infant rice seedling were 8-12cm, 1.5-1.7 leaves and 6.9-7. 5cm per seedling, respectively. The seedling growth at 10 days after transplanting was better at high temperatures (25/18$^{\circ}C$) than low temperature (20/12$^{\circ}C$) at transplanting, and the growth of infant rice seedling with endosperm -intacted was better than that with endosperm-removed. This tedency was shown significantly in transplanting at 20/12$^{\circ}C$ (day/night) of 4 days seedling.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.3
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• pp.308-318
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• 2013

Korean soybean varieties, 'Seonyu' and 'Hwangkeum' were planted in 2012, and three temperature gradient, Tc($19.8^{\circ}C$, ambient temperatured), $Tc+1.7^{\circ}C$, and $Tc+2.5^{\circ}C$, were artificially created by controlling the green house system during seed filling period. Mature seeds that developed under these conditions were analyzed for variances in physicochemical properties. The 100-seed weight and seed-coat ratio of soybean were decreased, but small seed rate was increased by high temperature during seed filling period. Protein content was increased, but oil content was decreased significantly with increasing the seed filling temperature. The decrement of carbon to nitrogen ratio (C/N), and the increment of monosaccharide, fructose and sucrose, in seeds explained that carbohydrate assimilation during seed filling was restricted by high temperature. Rapid increments of seed volume and weight were observed in the seeds of high seed filling temperature, but as soaking time increased the highest values were observed in the seeds of ambient seed filling temperature. The 100-seed weight and seed-coat ratio of soybean were closely related not only to the increment of soaking volume and weight, but also the increments of total dissolved solids (TDS) and electro conductivity (EC). Whereas protein content and C/N ratio showed less relationship with the soaking properties, but they had a positive correlation with TDS and EC. From the results, it was considered that high values of TDS and EC in the seeds of high temperature were mainly due to the incomplete conversion of assimilates into storage compounds. However, sugar content showed less influence on the soaking properties and the values of TDS and EC.