• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.15-20
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• 2017

In this paper, Esp8266, Node.js, and TCP / IP socket communication are used to design a compact data integration device. This device is designed to configure server and client using Esp8266 module that supports Wifi connection and to support bidirectional data transmission using TCP / IP socket communication. The server is configured using the Node.js operating system, and the database is integrated using Mysql. The network is designed to have a separate IP address by assigning a private IP address to the router, such as a home network. This device can transmit data bidirectionally, store individual client data on the server side, and can check the flow of data transmitted bidirectionally through wire-shark, so that it can be used as a compact real-time data integration and convergence device.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.177-182
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• 2010

Sediment transport around artificial habitat which is induced by the change of flow due to installation of the structure plays a role not only as a defect function of subsidence and burial but also bottom-environment control function. Using Side Scan Sonar (SSS), Differential Global Positioning System (DGPS) and Scuba diving equipment, we investigated a facility condition of a dice reef installed on Pohang coast of the East Sea. Investigation result, at total 139 place, 10,526 dice reef was discovered. As the level which affects function of the above 0.5m, the case 4 place of burial (0.5~1.2m, 2.9%), scour appeared with 3 place (0.5m, 2.2%) and broken was appeared with 183 artificial reefs (1.74%). As a result, dice reef installed Pohang coast appeared to mostly stable.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.3 s.147
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• pp.304-312
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• 2006

For protection of the thruster against mechanical damage and reduction of tunnel resistance at ship forward speed, the tunnel grids are normally installed. Some of ship operators however, have a strong distrust of the protective function of the tunnel grids and so they do not want to install the protective grids for higher thruster efficiency. Since the grids should be installed at very close to the side shell as far as possible in due consideration of flow direction to minimize additional resistance induced by tunnel openings, it has been too hard and time consuming work to install the grids on the curved and chamfered tunnel entrances considering its relatively low resistance reduction effect. DSME (Daewoo Shipbuilding & Marine Engineering Co., Ltd) developed a substituting device named TG (Tunnel Guides) for bow thruster tunnel grids which is characterized by higher resistance reduction, higher thruster efficiency and easy to installation. This paper provides the principle idea of the TG with short history of the development using CFD calculations and model experiments in MOERI (former KRISO).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.269-278
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• 2011

We investigate the heat-transfer and pressure-drop characteristics of fin-and-tube heat exchangers with a copper plate or copper spiral fins. Twenty-four samples with different fin pitches and tube rows were tested. For both configurations, the effect of the fin pitch on the j factor is negligible, and the f factor increases with the fin pitch. The effect of the tube row depends on the configuration. For plate fin-and-tube heat exchangers, the j factor decreases as the row number increases; the reverse is true for spiral exchangers. We explain this by considering the flow pattern. The j factor for plate fin-and-tube heat exchangers is larger than that for spiral exchangers, and the difference decreases as the row number increases. The f factor of the plate fin-and-tube heat exchanger is also larger. We compare our results with existing predictions of correlations.

• Neonatal Medicine
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• v.18 no.2
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• pp.365-369
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• 2011

Tetralogy of Fallot (TOF) assumes its' most severe form when accompanied by pulmonary atresia (PA). Preserving the patent ductus arteriosus to maintain pulmonary blood flow is life-saving for patients with this congenital heart disease. Milrinone, a selective phosphodiesterase III inhibitor, is a potent vasodilator. Here, we report the successful use of milrinone for a newborn infant with TOF and PA for keeping the ductus arteriosus open and thereby maintaining pulmonary circulation. Milrinone is a useful drug because of its inotropic, lusitropic, and pulmonary vasodilating effects, in addition to its ability to keep the ductus arteriosus open and its relatively mild side-effects. Case series and comparative studies will be needed in the future to verify the effectiveness of this drug.

• Journal of Energy Engineering
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• v.17 no.1
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• pp.1-7
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• 2008

The present study has been conducted to understand the heat and mass transfer characteristics of humid airflow in frosting conditions. A flat plate of aluminum was used for the simulation of flat surface part of the fin of the heat exchanger. The aluminum surface temperatures were measured and analyzed to clarify the heat and mass transfer characteristics under frosting conditions. Also, the pressure drops were measured to clarify the air-blocking effect of frost in the mini channel of the air-side hoot exchangers. A data reduction method was developed far the analysis of local characteristics of humid air under frosting conditions.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.73-82
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• 2012

The main and side reactions of the three selective catalytic reduction (SCR) reactions with ammonia over a vanadium-based catalyst have been investigated using synthetic gas mixtures in the temperature range of $170{\sim}590^{\circ}C$. The three SCR reactions are standard SCR with pure NO, fast SCR with an equimolar mixture of NO and $NO_2$, and $NO_2$ SCR with pure $NO_2$. Vanadium based catalyst has no significant activity in NO oxidation to $NO_2$, while it has high activity for $NO_2$ decomposition at high temperatures. The selective catalytic oxidation of ammonia and the formation of nitrous oxide compete with the SCR reactions at the high temperatures. Water strongly inhibits the selective catalytic oxidation of ammonia and the formation of nitrous oxide, thus increasing the selectivity of the SCR reactions. However, the presence of water inhibits the SCR activity, most pronounced at low temperatures. In this study, the experimental results are analyzed by means of a dynamic one-dimensional isothermal heterogeneous plug-flow reactor (PFR) model according to the Eley-Rideal mechanism.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.1-8
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• 2001

This study deals with the experimental and numerical investigations to design the high performance otter board. Experiment was carried out to determine the most effective slot size of single-slot cambered otter board in the circulation water channel of BAEK KYUNG IND. Co. LTD. Numerical analysis was done by the commercial CFD code, FLUENT, to provide some valuable physical interpretations and finally to design the otter board section by numerical method. The major results are as follows ; 1. In experiment, the maximum lift and drag coefficients of simple cambered type otterboard were 1.41, 0.55, respectively, at the angle of attack $28^\circ$, while those of slot one with slot size 0.02C (C denotes the chord length) were 1.72, 0.42 at the angle of attack $24^\circ$. 2. The hydrodynamic characteristics depending upon slot size shows the greatest at 0.02C of the slot size. 3. Numerical results well visualized the streamlines, pressure fields, and speed vectors of a simple cambered and slot cambered otter board with slot size 0.02C. The slot cambered one with slot size 0.02C was shown that pressure field was distributed moderately on front and back side of otter board. And, the delay and decrease of separation were favorably achieved by flow through slot. 4. Computed result on the pattern of hydrodynamic field and the values of $C_L$ and $C_D$ by the commercial CFD code, FLUENT, show almost the same as those of the experimental result.

• Fire Science and Engineering
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• v.29 no.3
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• pp.31-36
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• 2015

This study analyzed the flame characteristics when igniting 200 ml of flammable liquids containing equal parts gasoline and another flammable liquid. These mixtures were used to fill a divided space in a simulation. The length of one side of the divided space was 2,000 mm, and the length of the combustion device was 1,000 mm. The mixture with alcohol had the highest flame propagation speed (0.7 s), while the mixture with light oil showed the lowest (1.2 s). The gasoline and acetone mixture reached peak flame in 25.5 s, at the highest speed, while the mixture with light oil reached peak flame in 163.7 s at the lowest speed. The gasoline and light oil showed the longest continuous combustion time (332.7 s), while the gasoline and paint thinner showed the shortest (121.5 s). A fire inspector who is examining the scene of a fire needs to analyze both the statements of the first eyewitness and the flame characteristics collectively.

• Journal of the Korean Wood Science and Technology
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• v.18 no.3
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• pp.42-52
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• 1990

In this study, thick 24mm glulams were composed of thick. 3, 4, 6, 8mm Larch laminas to study that the theoretical analysis and the experimental analysis regarding the location of neutral axis of the glulams were compared, and to study on the effect of location of neutral axis on mechanical properties of glulam. The variation of location of neutral axis after proportional limit(or elastical limit) was studied to offer basic data to make the better composition method of glulam. The result obtained can be summarized as follows: 1. The theoretical neutral axis was 0.547 in solid wood, and also 0.547 in glulams because glulams were composed of only Larch laminas. 2. In solid wood, the deviation of the theoretical and the experimental neutral axis location was 0.1%, But in glulams, the deviation from-12.2% to + 7.8% showed nonuniform pattern but no large deviation. Because laminas was only of Larch and so the mechanical properties of laminas were monotonous. 3. The neutral axis exerted no influance on the elasticity of glulam, which meaned that the maximum shear strength in the neutral axis showed no influance on elasticity limit. 4. The only minutely lower elasticities of glulam than that of solid wood were shown. This was because of influance of glue lines of glulam on the elasticlties. 5. The failure type of glulam was wholly simple tension failure and the horizontal shear failure near neutral axis was not taken place, which was that glue line was complete in bonding and the strength of the lamina was not various but uniform. 6. The ratio of tension strain($^{\varepsilon}t$) I compression strain($^{\varepsilon}c$) initially showed uniform level After the elasticity limit. the ratio was increased with the flow of time and so the tension strain was more increased than compression strain. So this proved tension lamination technique, which is that the mechanical properties of glulam could be improved, if the lamina of more superior strength would he added on the bottom side of the glulam.