• Journal of Animal Environmental Science
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• v.17 no.3
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• pp.155-162
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• 2011

This study was conducted to suggest the measurement procedure and to build up national greenhouse gas inventory database of animal agricultural sector by assessing methane and nitrous oxide emissions according to IPCC guidelines for national greenhouse gas inventory report in order to correspond to the Climate Change Convention. Ten house-made steady-state Half dome floating chambers were used to collect air samples emitted from slurry stored in the pit under the slat. Those chambers were spread out in order that air samples might represent the whole area of slurry under the slat. Fresh air was pumped into the chambers by $5{\sim}9{\ell}/min$ and air inside the chambers was sampled by $1{\ell}/min$. Surplus air by the higher flow rate of fresh air than sampling flow rate was passed through a hole on the top of chambers. Nitrous oxide fluxes measured from 10 locations would be negligible as concentrations between background air and sampled air from the chambers were within the error range. However, mean $CH_4$ fluxes were $0.15{\sim}1.02mg/m^2{\cdot}s$. The application of continuous greenhouse gas measurement techniques would be preferred if the patterns of greenhouse gas emissions are considered.

• Journal of Chest Surgery
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• v.27 no.7
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• pp.624-627
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• 1994

Congenital coronary arteriovenous fistula is a rare cardiac defect that causes coronary arterial flow to drain into the right cardiac chambers, the pulmonary artery, the coronary sinus, or the left cardiac chambers. The most frequently involved vessel is the right coronary artery. We experienced a case that had a coronary arteriovenous fistula associated with valvular heart disease. With the cardiopulmonary bypass done under hypothermia, mitral valve replacement was accomplished and the fistulas of both proximal and distal portions of the right coronary artery were closed with 3-0 prolene. Postoperative course was uneventful.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.127-130
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• 2003

This paper presents the numerical thermal analysis for regeneratively cooled rocket thrust chambers. An integrated numerical model incorporates computational fluid dynamics for the hot-gas thermal environment, and thermal analysis for the liner and coolant channels. The flow and temperature fields in rocket thrust chambers is assumed to be axisymmetric steady state which is presumed to the combustion liner. The heat flux computed from nozzle flow is used to predict the temperature distribution of the combustion liner. As a result, we present the wall temperature of combustion liner and the temperature change of coolant.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.163-184
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• 2004

Vortex flow fundamentals have been investigating for about hundred years and many distinguished features had been discovered and comprehensively studied over that time. Due to unique hydrodynamic features vortex flows are now widely used in many industrial applications, including energy and power systems. combustion chambers. fuel sprayers. heat exchangers. clean-up systems. drying chambers. Up to recently aerospace engineers employed vortex flow only in combustion systems to stabilize a flame zone or in advanced heat exchangers to enhance heat transfer processes. This paper provides an overview of some recently developed aerothermal vortex technologies applied to aerospace engineering.

• Journal of the Korean Society of Combustion
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• v.2 no.1
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• pp.17-27
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• 1997

It is well known that NOx formation has a strong dependence on the maximum temperature and correspondingly with the maximum chamber pressure of a closed combustion system. However, in a case of impinging-jet-flame (IJF hereafter) combustion with opposed dual pre-chambers, low $NO_x$ formation with high pressure could be achieved, but its mechanism has not been clearly understood so far. In this study, a three-dimensional analysis is adopted to resolve time-variant local properties that might indicate the mechanism of IJF combustion. Numerical results are verified by comparing them with experiments. The IJF combustion in a vessel with no pre-chamber, with single pre-chamber, and with dual pre-chambers is studied. The orifice diameter and the volumetric ratio of pre-chamber are used as geometric parameters. The effects of main-chamber ignition delay time and combustion time of main-chamber, orifice exit velocity, orifice exit temperature, turbulent kinetic energy of main-chamber and spatial distribution of temperature in the latter stage of combustion are investigated. A longer main-chamber ignition delay and a shorter main-chamber combustion time suppress the formation of high temperature region with respect to mean temperature, which consequently results in less NO production.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5B
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• pp.459-467
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• 2006

In this study, hydraulic and numerical model experiments were performed to analyze and improve the effects of flow-rate increase in the intake canal of Boryeong Thermal Power Plants on the flow condition in the circulation water pump (CWP) chambers. Based on the numerical simulation results, when the flow-rate increased in the circulation water intake canal, the velocity in the canal and vertical vorticities in the circulation water pump chambers increased and hence the vortex occurrence potential would be greatly increased. It was found by performing hydraulic model experiments that the velocity distribution near the bottom in the inlet of the circulation water pump chambers was highly non-uniform while the velocity distribution near the water surface was nearly uniform. To reduce the non-uniformity in the velocity distribution, triangular flow deflectors were devised. The installation of the flow deflectors in the inlet of circulation water pump chambers was successfully to reduce velocity non-uniformities and to remove flow reversal problems.

• Archives of Plastic Surgery
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• v.37 no.2
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• pp.105-109
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• 2010

Purpose: The purpose of this study is to determine the effect of platelet-rich plasma (PRP) on rat sciatic nerve regeneration in a 10 mm silicone chamber. Methods: A total of 6 inbred Lewis rats were used in this study. Bilateral sciatic neurectomy was performed on each rat. On one side, silicone chambers containing PRP solutions were implanted; on the contralateral side, the chambers without PRP were implanted as a control. In 12 weeks post-implantation, chambers were retrieved and both gastrocnemius muscles were excised. Nerves biopsy samples were examined under a light microscope after Masson trichrome staining. Results: Cross sections of the midpoints of PRP treated nerves were significantly larger and appeared more mature than those of controls. Conclusion: Based on morphological evidence, PRP has a positive effect on neural regeneration, and it may therefore be useful for treating peripheral nerve injuries.

• The Korean Journal of Zoology
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• v.30 no.1
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• pp.10-28
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• 1987

Changes of protein synthesis in the isolated egg chambers were studied during oogenesis of Drosophila melanogaster. Protein synthesis did not change much in quantity except that the activity was slightly enhanced at the stages 11 and 12, when new structures such as vitelline membranes and yolk granules were made, but considerably changed in quality during oogenesis. Protein synthesis was believed to occur mainly in the follicle cells, and a number of stage-specific proteins were found to differ at various stages. The observations suggest that proteins synthesized in the cells within chambers as well as those from the outside of the chambers might be directly required for the growth and maturation of oocytes in Drosophila.

• Agricultural and Biosystems Engineering
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• v.2 no.1
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• pp.31-36
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• 2001

Based on the viscous flow characteristics of gas through capillary tube, a simple and cheap gas mixing system was developed for controlling gas compositions in CA chambers. The gas flow rate through capillary tube had a linear relationship with pressure, (length)$^{-1}$ and (radius)$^4$ of capillary tube, which agreed well with Hagen-Poiseuille’s law. The relationship between flow rate and combined parameters was described as Q=0.000209724($\pi$ r$^4$P/$\mu$L) and the coefficient of determination was 0.9984. The developed system could control gas concentrations in CA chambers within $\pm$0.3% deviation compared to the preset concentrations. It was possible to predict the required time and required gas flow rate for exchanging the gs in CA chamber to a certain concentration of gas by using the mathematical model developed in this study.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.2
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• pp.159-167
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• 2002

The operation results of the 2kW class plate type reformer, which has several advantages compared with the tubular burner type reformer, are analyzed. This plate type reformer is composed of six combustion chambers and five reforming chambers by turns. The methane conversion rate at 1.6 absolute pressure is about 84%, which is reasonably similar to theoretical value, 85.3%. Though the abrupt interruption was made just by the carbon deposition during heating the fuel line to combustion chambers around 200 hours operation, the overall steady state operation is more than 450 hours. These operation results show the verification of long run performance and the possibility of direct connection between plate reformer and fuel cell stack.