• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 2010.04a
• /
• pp.166-170
• /
• 2010

Six different size of torch-ignition device were applied in a constant volume combustion chamber for evaluating the effects of torch-ignition on combustion. The torch-ignition device was designed six different volumes and same orifice size. The combustion pressures were measured to calculate the mass burn fraction and combustion enhancement rate. In addition, the flame propagations were visualized by shadowgraph method for the qualitative comparison. The result showed that the combustion pressure and mass burn fraction were increased when using the torch ignition device. And the combustion duration were decreased. The combustion enhancement rates of torch-ignition cases were improved in comparison with conventional spark ignition. Finally, the visualization results showed that the torch-ignition device the torch-ignition induced faster burn than conventional spark ignition due to the earlier transition to turbulent flame and larger flame surface, during the initial stage. And the initial flame propagation was effected torch-ignition volume.

• Clinical and Experimental Pediatrics
• /
• v.51 no.11
• /
• pp.1179-1184
• /
• 2008

Purpose : Pulmonary interstitial emphysema (PIE) primarily occurs in preterm infants suffering from respiratory distress syndrome (RDS) and kept under mechanical ventilator care. Therefore, this study aimed to examine various risk factors for PIE, to identify conditions that can decrease the possibility of PIE development. Methods : PIE classification was conducted for 183 patients diagnosed to have RDS and receiving mechanical ventilator care with pulmonary surfactant between March 2000 and February 2007. The characteristics of each patient were analyzed through retrospective examination of their medical histories. Results : Among 183 patients, 17 had PIE; all factors, including birth weight, gestational age, RDS grade III or above, chorioamnionitis, and premature rupture of membranes, were statistically significant (P<0.05). The period of mechanical ventilator use was statistically significant, but the peak mean airway pressure and peak partial pressure of inspired oxygen were not. PIE mainly occurred on the right side or both sides rather than the left side and mostly developed within 72 h. The PIE group showed higher mortality rate than the control group, and the major cause of mortality was pneumothorax. Conclusion : Risk factors for PIE in infants suffering from RDS and kept under mechanical ventilator care include low gestational age, low birth weight, chorioamnionitis, and premature rupture of membranes. If any risk factors are noted, the infant must be observed closely for at least 72 h after birth.

• Analytical Science and Technology
• /
• v.30 no.5
• /
• pp.279-286
• /
• 2017

Determination of the order of latent fingerprints deposition on the surface of thermal paper, often found in crime scenes, is related to the study of time course and aging of fingerprints and can provide additional information in criminal investigations. A preliminary study was performed to determine the deposition order of fingerprints left with two different conditions of deposition pressure and time (in seconds) after 1 day intervals for 7 days on thermal paper (receipt and fax thermal paper) using an iodine fuming method. The resultant images of the visualized fingerprints were analyzed with densitometric image analysis to measure the changes in the areas of the ridges, which can be correlated to the deposition order. No significant variation was found with the different types of thermal paper. The average areas of the friction ridges increased gradually or were similar to the values from day 1 for 3 days, and then a continual decrease was shown from day 4 through day 7. The area values from day 6 and day 7 were less than half of those from day 1. Furthermore, the test with overlapped fingerprints showed the possibility of differentiation between fingerprints that are 1-3 and 6-7 days old based on the clarity visible to the naked eye. Additional experiments with the deposition conditions can prove that the current method is valuable for the determining the order of fingerprint deposition on thermal paper.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.16 no.1
• /
• pp.123-136
• /
• 2018

The objective of this study is to propose a new methodology to fabricate a reliable engineering-scale buffer block, which shows homogeneous and uniform distribution in buffer block density, for in-situ experiments. In this study, for the first time in Korea, floating die press and CIP (Cold Isostatic Press) are applied for the manufacture of an engineering-scale bentonite buffer. The optimized condition and field applicability are also evaluated with respect to the method of manufacturing the buffer blocks. It is found that the standard deviation of the densities obtained decreases noticeably and that the average dry density increases slightly. In addition, buffer size is reduced by about 5% at the same time. Through the test production, it is indicated that the stress release phenomenon decreases after the application of the CIP method, which leads to a reduction in crack generation on the surface of the buffer blocks over time. Therefore, it is confirmed that the production of homogeneous buffer blocks on industrial scale is possible using the method suggested in this study, and that the produced blocks also meet the design conditions for dry density of buffer blocks in the AKRS (Advanced Korea Reference Disposal System of HLW).