• Journal of the Korean Geosynthetics Society
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• v.13 no.2
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• pp.1-10
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• 2014

In this study, two different types of dredged fill injection methods are introduced and filling experiments were conducted to analyze the impact of each technique to the distribution and deposition of dredged soil fill and how it influence the final tube shape. Two transparent plastic tubes were fabricated to observe the deposition behavior of the deposited fill material. Both tubes measured 4.0 meters in length (L) and has vinyl tube diameters (D) of 0.5m and 0.7m. T-type and I-type inlet system are also introduced in this paper. The influence of this inlet systems to the distribution and deposition behavior of dredged soil fill inside the vinyl tubes were observed during the experiment. After the sedimentation of the slurry mixture, the water on top of the soil sediments are removed and the slurry mixture was re-injected into the vinyl tube, this process was carried out repeatedly. The shape changes of the vinyl tube, e.g. the changes in both tube height and width, are constantly monitored after each slurry injection and water draining phases. Crater formation was observed in the case of I-Type inlet system and a non-uniform sediment distribution occurred. For the diffusion deposit of soil particles to long distance are minimal shape technique using the T-Type inlet system. Therefore the undrain filling height ratio ($H/D_0$) was found to be around 0.54 to 0.64 and the horizontal strain ratio ($W/D_0$) ranges from 1.45 to 1.54. The filling soil height is proportional to dredged-material filling phases, but, horizontal strain ratio is constant or inversely reduced so that the center of tube body is raised in the upward direction.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.265-272
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• 2008

In this paper, AC losses of long wire Bi-2223 tapes with different twist pitch of superconducting core were fabricated, measured and analyzed. These samples produced by a powder-in-tube method are multi-filamentary tape with Ag matrix. Also, it's produced by non-twist. The critical current measurement was carried out under the environment in Liquid nitrogen and in zero field by 4-prob method. And the Magnetic measurement was carried out under the environment of applied time-varying transport current by transport method. From experiment, the susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation. Neutron-diffraction measurements have been carried out investigate the crystal structure, magnetic structures, and magnetic phase transitions in Bi-2223([Bi, Pb]:Sr:Ca:Cu:O).

• Journal of Energy Engineering
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• v.14 no.2 s.42
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• pp.98-104
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• 2005

Pannier-arrangement condensers are usually adopted in the turbine generator units of combined cycle power plants. Optimization of operating performance and economy is an important goal, which requires accurate understanding of flow and heat transfer effects in the condenser. The tube bundle arrangement and steam flow behaviors of pannier-arrangement condensers are very different from those of common condensers. The physical model for existing numerical simulation program of condenser is refined by constructing the correlations for flow resistance and condensation heat exchange coefficient in which the influences of steam flow direction are considered according to available experimental data. The adaptability of the developed physical model and simulation program of pannier-arrangement condenser is verified with available experimental data.

• Journal of Power System Engineering
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• v.15 no.4
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• pp.11-18
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• 2011

A Shock absorber is one of the most important components in vehicle suspension systems. In general, many repeated analyses are required for the design of a shock absorber to satisfy the suspension characteristics of a specific automobile, like fluid flow analysis and mechanical analysis. The purpose of this study is to develop a fast design tool for shock absorber designers. One of the efficient solutions for this can be an empirical design method considering phenomenological effects from the shock absorber design variables. In order to extract the shock absorber's experimental characteristics, we used Taguchi method. This method showed that which design variables have major effects for the shock absorber's damping characteristics. This empirical design method also showed the direction of the design changes to satisfy the designer's intension.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1667-1672
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• 2007

In order to assess the reliability of the exhaust bellows for automobiles, accelerated life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows; i) the main failure mechanism is crack or breakage of inner flexible tube by shaken displacement at shear direction. ii) temperature is a second factor to affect a failure. iii) the life distribution of exhaust bellows is fitted well to Weibull life distribution and the shape parameter is 13.3 on condition of shaken displacement and $600^{\circ}C$

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.242-247
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• 2004

An Experimental study was conducted on spray combustion using dual swirlers at different outlet angle; co-swirl and counter-swirl. To understand the characteristics of turbulent spray combustion of dual swirl flow (DSF), the axial helical annular vaned swirlers with various swirl ratios and combination of angle and direction were designed. and temperature measurements of a rapidly thermocouple insertion and measurements of soot volume fraction and microrstructure using thermophoretic sampling particle diagnostic (TSPD) as TEM were carried out. The NOx, $CO_2$, $O_2$, etc. was analyzed using emission gas analyzer. The results show that flame stability were maintained under very lean condition. for both co-swirl and counter-swirl case. And though Counter-swirl case kept the higher temperature region compared to co-swirl case, Counter-swirl combustion represented less NOx emission and soot formation than co-swirl case.

• Journal of Korean Neurosurgical Society
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• v.42 no.4
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• pp.245-250
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• 2007

Tubular retractor system as a minimally invasive surgery (MIS) technique has many advantages over other conventional MIS techniques. It offers direct visualization of the operative field, anatomical familiarity to spine surgeons, and minimizing tissue trauma. With technical advancement, many spinal pathologies are being treated using this system. Namely, herniated discs, lumbar and cervical stenosis, synovial cysts, lumbar instability, trauma, and even some intraspinal tumors have all been treated through tubular retractor system. Flexible arm and easy change of the tube direction are particularly useful in contralateral spinal decompression from an ipsilateral approach. Careful attention to surgical technique through narrow space will ensure that complications are minimized and will provide improved outcomes. However, understanding detailed anatomies and keeping precise surgical orientation are essential for this technique. Authors present the technical feasibility and initial results of use a tubular retractor system as a minimally invasive technique for variaties of spinal disorders with a review of literature.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.75-78
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• 1999

This paper is concerned with the family of parts that generally feature a central hub with radial protrusions. Typical parts that fall into this category include cross Pieces for universal joints, tube fittings, and differential gears. As opposed to conventional forward and backward extrusion, in which the material flows in a direction parallel to that of the punch or die motion, the material flows perpendicular to the punch motion in radial extrusion. In this study, the forming characteristics of radial extrusion will be considered by comparing the forces, shapes etc. The design factors during radial extrusion are investigated by the rigid-plastic FEM simulation.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.87-95
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• 2006

The outlet feeder pipe thinning in a PHWR (Pressurized Heavy Water Reactor) is caused by a high pressure steam flow inside the pipe, which is a well known degradation mechanism called a FAC (Flow Assisted Corrosion). In order to monitor the degradation, the thickness of the outlet bends close to the exit of the pressure tube should be measured and analyzed at every official overhaul. This paper describes a mobile feeder pipe inspection robot that can minimize the irradiation dose to human workers by automating the measurement process. The robot can move by itself on the feeder pipe by using an inch worm mechanism, which is constructed by two gripper bodies that can fix the robot body on to the pipe, one extendable and contractible actuator, and a rotation actuator connected to the two gripper bodies to move forward and backward, and to rotate in a circumferential direction.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.346-351
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• 2005

The outlet feeder pipe thinning in a PHWR (Pressurized Heavy Water Reactor) is caused by high pressure steam flow inside the pipe, which is a well known degradation mechanism called FAC (Flow Assisted Corrosion). In order to monitor the degradation, the thickness of the outlet bends closed to the exit of the pressure tube should be measured and analyzed at every official overhaul. This paper develops a mobile feeder pipe inspection robot that can minimize the irradiation dose of human workers by automating the measurement process. The robot can move by itself on the feeder pipe by using an inch worm mechanism, which is constructed by two gripper bodies that can fix the robot body on the pipe, one extendable and contractable actuator, and a rotation actuator connected the two gripper bodies to move forward and backward, and to rotate in the circumferential direction