• Journal of the Korean GEO-environmental Society
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• v.14 no.3
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• pp.51-60
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• 2013

It is proposed the new method to calculate the absolute altitude and horizontal position of worker in construction field. For this research, we used a pressure sensor, MEMS INS sensor to acquire 3D position of worker. The easiest way to show the result of this research is to use smart phone which equipped various digital sensors in this hardware. So we made two softwares: Data acquisition software in Android smart phone and Data monitoring software in PC. During this research, we encountered several kind of problems which have to be overcame. This paper shows these processes and the results of 3D positioning technologies we suggested newly.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.477-483
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• 2020

The rehabilitation methods used in existing concrete box structures rely on the method of attaching the repair material to the section of the structure with a spray equipment. In the case of ceiling or wall parts, the adhesion force to the repair material may be reduced by the gravity and dead load after construction. In subway structures, vibration causes a problem that reduces the initial adhesion. Supplementary measures are needed as the quality of repair varies depending on the worker's proficiency and construction environment. In this study, mechanical pressurization equipment was developed that can apply a certain pressure after construction of a repairwork to solve problems such as reduction of adhesion of repair materials by gravity and variation of repair quality by labor work. To find out the effect of the pressurized equipment, a chamber similar to the field conditions was constructed to measure the attachment strength different from the pressurized condition, the section, and the environmental conditions. The pressurization differed from the other parts, but the adhesion strength of up to 70% was increased.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.20-26
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• 2002

The purpose of this study is preventing the stick, scuffing, scratch between piston and cylinder in advance, and obtaining data for duration test in actual engine operation. The temperature gradient in cylinder bore according to coolant temperature were measured using $1.5{\ell}$ class diesel engine. 20 thermocouples were installed 2mm deep inside from cylinder wall near top ring of piston in cylinder block, at which points major thermal loads exist. It is suggested as proper measurement points for engine design by industrial engineers. Under full load and $70^{\circ}$, $80^{\circ}C$ and $90^{\circ}C$ coolant temperature conditions, the temperature in cylinder block and engine oil increased gradually according to the increase of coolant temperature, the siamese side temperature of top dead center is $142^{\circ}C$ in peripheral distribution, that is about $20^{\circ}C$ higher than that at thrust, anti-thrust, and rear side temperature, respectively. The maximum pressure of combustion gas in $70^{\circ}C$ coolant temperature is about 2 bar lower than those of $80^{\circ}C$ and $90^{\circ}C$ coolant temperature. The engine torque in $80^{\circ}C$, $90^{\circ}C$ coolant temperature condition is about 4.9Nm higher than that of $70^{\circ}C$ coolant temperature.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.1197-1205
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• 1988

An analytical method to predict qualitative performance characteristics of the Stirling Engines in the preliminary design stages is investigated. Both the expansion and the compression cylinder are treated as adiabatic and piston motions are approximated as saw-toothed waves. Basic equations which were originally proposed by Finkelstein consist of mass conservation and energy balances for each adiabatic cylinder. The approximation on piston motions and physical conditions make it possible to divide an engine cycle into four fundamental processes. In each process, first, pressure can be expressed as a function of the crank angle by solving a nonlinear first order ordinary differential equation and other thermodynamic variables are determined in turn. Application of the cyclic steady condition to the whole processes can complete a cycle. Also, further analysis results in analytic expressions for cyclic work and heat transfer in terms of the engine parameters and thermodynamic variables at boundary points. The results are expected useful as a quick reference for the engine performances. Finally, the present method can be applied to the other adiabatic analyses on the Stirling Engines with piece wise linear piston motions, if mass variations are predictable.

• Clean Technology
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• v.24 no.4
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• pp.348-356
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• 2018

The adsorption equilibria of oxygen, nitrogen and argon on carbonaceous adsorbent with slit-shaped and randomly etched graphite (REG) pores were calculated by molecular simulation method. Reliable models of adsorbents and adsorbates for adsorption equilibria are important for the correct design of industrial adsorptive separation processes. At the smallest physical pore of $5.6{\AA}$, only oxygen molecules were accommodated at the center of the slit-shaped pore, and from $5.9{\AA}$ nitrogen and argon molecules could be accommodated in the pores. Slit pores showed higher adsorption capacity compared with REG pores with same averaged reenterance pore size due to dead volume and inaccessible volume in defected pores. And it was shown the adsorption capacities of oxygen and argon was same in larger pore size. From calculated adsorption isotherms at 298 K it showed that the adsorption capacity ratio of oxygen to nitrogen is increased as pressure is increased.

• Explosives and Blasting
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• v.22 no.3
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• pp.57-64
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• 2004

There are two major types of underwater blasting at Korea, bridges and harbor construction work. Pier blasting for lay the foundation bridges construction is used dry excavation working (drilling and charging) after pump out water and then fire pump in water that is same as bench blasting. In contrast, underwater blasting for harbor construction and increase of harbor load depth is used to barge with digging equipment that is in oder to drilling on the surface and blasting work(charge, hook-up) under water. Thus, there are need to special concern such as charge method and hook-up method different from tunnel blasting work and bench blasting work. If do not use special concern breaks out dead pressure and mis fire because of there are so many difficult condition such as water pressure, obstruct field of vision. In this study underwater blasting at Busan Harbor Construction have consider with special concern that is plastic pipe charge method used to MegaMITE I and specialized buoy hook- up method make far initial system detonate on the surface used to TLD. The results is designed blast pattern charge per delay effect an inspection of verify between predict velocity and measure velocity. minimized break out mis fire consideration charge method, hook up method. According to result best underwater blasting design is 105mm drilling dia, MeGAMITE II, HiNLL Plus(non electric detonator).

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.295-302
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• 2014

This study demonstrates a double-path CDI as an alternative of advanced wastewater treatment process. While the CDI typically consists of many pairs of electrodes connected in parallel, the new double-path CDI is designed to have series flow path by dividing the module into two stages. The CFD model showed that the double-path had uniform flow distribution with higher velocity and less dead zone compared with the single-path. However, the double-path was predicted to have higher pressure drop(0.7 bar) compared the single-path (0.4 bar). From the unit cell test, the highest TDS removal efficiencies of single- and double-path were up to 88% and 91%, respectively. The rate of increase in pressure drop with an increase of flow rate was higher in double-path than single-path. At 70 mL/min of flow rate, the pressure drop of double-path was 1.67 bar, which was two times higher than single-path. When the electrode spacing was increased from 100 to $200{\mu}m$, the pressure drop of double-path decreased from 1.67 to 0.87 bar, while there was little difference in TDS removal. When proto type double-path CDI was operated using sewage water, TDS, $NH_4{^+}$-N, $NO_3{^-}$-N and $PO_4{^{3-}}$-P removal efficiencies were up to 78%, 50%, 93% and 50%, respectively.

• Solar Energy
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• v.10 no.3
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• pp.3-12
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• 1990

This paper deals with experimental research to increase thermal storage efficiency of hot water stored in an actual storage tank for solar application. The effect of increased energy input rate due to stratification has been discussed and illustrated through experimental data, which was taken by changing dynamic and geometric parameters. Ranges of the parameters were defined for flow rate, the ratio of diameter to height of the tank and inlet-exit water temperature difference. During the heat storage, when the flow was lower, the temperature difference was larger and the ratio of diameter to height of the tank was higher, the momentum exchange decreased. As for this experiment, when the flow rate was 8 liter/min, the temperature difference was $30^{\circ}C$ and the ratio of diameter to height of the tank was 3, the momentum exchange was minimized resulting in a good thermocline and a stable stratification. In the case of using inlet ports, if the modified Richardson number was less than 0.004, full mixing occured and so unstable stratification occured, which mean that this could not be recommended as storage through thermal stratification. Using a distributor was better than using inlet ports to form a sharp thermocline and to enhance the stratification. It was possible to get storage efficiency of 95% by using the distributor, which was higher than a storage efficiency of 85% obtained by using inlet ports in same operation condition. Furthermore, if the distributor was manufactured so that the mainpipe decreases in diameter toward the dead end to maintain constant static pressure, it might be predicted that further stable stratification and higher storage efficiency are obtainable(ie:more than 95%).

• Journal of Chest Surgery
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• v.31 no.10
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• pp.1004-1008
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• 1998

We report a case of heart-lung transplantation in a 32 year-old female with Eisenmenger syndrome secondary to patent ductus arteriosus. She has been suffered from congestive heart failure since June 1996 and repeatedly treated at Intensive Care Unit with intravenous inotropic support since July 1997. Preoperative echocardiography showed a patent ductus arteriosus with right to left shunt, severe regurgitation of tricuspid valve and estimated right ventricular systolic pressure of 100mmHg. The brain-dead donor was an 18 year-old male with head trauma from traffic accident 3 days ago. Heart-lung block procurement was performed at another general hospital and was transported to the Seoul National University Hospital by ambulance. Total ischemic time of the transplanted heart and lung were 249 minutes and 270 minutes, respectively. The immunosuppressive therapy was commenced preoperatively with cyclosporine and azathioprine. Corticosteroid was not used until postoperative 3 weeks in order to avoid infection and delayed healing at the tracheal anastomotic site. The patient was discharged at 31st postoperative day, and has been regularly followed up at outpatient clinic without specific complication. The follow-up bronchoscopy, performed 2 weeks and 4 months after surgery, revealed no evidence of cellular rejection.

• Journal of Trauma and Injury
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• v.22 no.1
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• pp.71-76
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• 2009

Purpose: The goal of this study was to compare the outcome of the after trauma team (AfterTT) group to the before trauma team (BeforeTT) group. Methods: All trauma patients who visited to emergency room (ER) between July 1, 2006 and February 29,2008 based on trauma registry, with systolic blood pressure (SBP) < 90 mmHg or GCS < 9 were included in this study. We compared the amount of packed RBC transfusion, the ER stay time, the ER visit to CT evaluation time, the ER visit to operation time, the length of ICU stay, the length of hospital admission and the survival discharge rate between the AfterTT group and the BeforeTT group. Patients with brain injuries had little chance of survival. Burn patients, who visited the ER 24 hours after injury and patients who were dead on arrival (DOA) were excluded from this study. Results: Total of 93 patients were included in this study: 42 in the AfterTT group and 51 in the BeforeTT group. The AfterTT group and the Before TT group showed no differences in Revised Trauma Score (RTS) and mean age. The amount of packed RBC transfusion was lower in the AfterTT group, but no statistically significant difference was noted (AfterTT 11${\pm}$11units, BeforeTT 16${\pm}$15units, p=0.136). The ER visit to operation time was shorter in the AfterTT group, but there were no statistically significant difference between the groups (AfterTT 251${\pm}$223 minutes, BeforeTT 486${\pm}$460 minutes, p=0.082). The length of ICU stay was shorter in the AfterTT group, but the difference was not statistically significant (AfterTT 11${\pm}$12 days, Before TT 15${\pm}$30 days, p=0.438). The length of Hospital admission was shorter in the AfterTT group (AfterTT 43${\pm}$37 days, BeforeTT 68${\pm}$70 days, p=0.032), but this difference was not statistically significant. Conclusion: Simple Trauma team activation criteria decreased the amount of packed RBC transfusion and the hospital admission duration. Hemodynamic instability (SBP < 90 mmHg) and decreased mental state (GCS<9) are good indices for activating the trauma team.