• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.83-84
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• 2006

Due to the capability of net shaping for complex 3D geometry, powder injection molding (PIM) is widely used for automotive parts, electronics and medical industry. In this study, an ultrasonic dental scaler tip produced by machining process was redesigned for the PIM process. An injection mold was designed and manufactured to produce the dental scaler tip by the PIM process.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.4
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• pp.355-361
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• 2009

In this paper, an analysis technique is presented for performing the effective design of bus structure. Sensitivity analysis is carried out for the natural frequency of component structures consisting of bus B.I.W. Local vibration modes of substructure, which large affect on the global vibration mode of the bus B.I.W., are obtained through the sensitivity analysis technique using the mathematical chain rule. And also the design variables, which are determined from the sensitivity analysis, are redesigned through optimum design process. The proposed analysis technique shows that the bus structure can be effectively designed considering the vibration characteristics.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.436-439
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• 2005

Condenser tube has been used as a component of heat exchanger in automobile and air conditioning apparatus. In this paper, porthole die extrusion that is advantageous to form long hollow section tube is analyzed by direct extrusion of condenser tube with 12 holes. A study on extrusion process is performed through the 3D FE simulation at non-steady state and extrusion experiments. Especially, weldability, extrusion load and die defects were estimated try FE-simulation. This study present the redesigned die of direct extrusion in consideration of the results obtained from FE-analysis.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.595-600
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• 2003

This paper presents the applicability of low caloric synthetic gas from coal gasification to a gas engine system. A commercial LPG engine is modified to use the low caloric synthetic gas from coal gasification as the gas engine fuel. The modification is focused on the fuel supplying system, which includes air flowrate adjusting orifice, gas mixer, vaporizer, preheater, regulators, and fuel tank. The electrical system and others for the alternative fuel are also redesigned and replaced. From the results of engine performance data, we have demonstrated that the engine modified by using coal gasification gas is well operated from idle to wide open throttle conditions although the engine power is somewhat reduced relative to LPG fueled engine. This paper addresses the need to determine the practical potential for such a concept and to identify further research and development efforts that may be necessary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4784-4789
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• 2014

This paper evaluated the structural improvements and new product development of cleaning machines. A cleaning machine was redesigned for structural improvements and new product development using a 3-D design program CATIA. In addition, structural analysis was conducted on the modeled cleaning machine using the ANSYS program. The total deformation, stress and strain were obtained by the pressure change. This result was applied to the new product development of cleaning machines.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.2
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• pp.311-322
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• 1996

To accomodate workers with efficient mobility, coveralls were redesigned, construted and evaluated. In this study, especially, image processing techniques were applied to the evaluation stage, to quantify thE ease of body movement. For the initial observation stage, car-center workers were interviewed and their movements were videotaped. By analyzing the videotape, the area of stress and strains on the work clothes were marked on the figure chert and considered for the pattern making. 4DM cut pattern were applied to the upper part of the work clothes and other alternations were made throughout the problem area. Honey comb slashes were made on the problem area of the original and newly designed coveralls. Open areas of honey comb slashes due to body movement between the original and newly designed coveralls were analyzed by image processing techniques. Other objective and subjective evaluation of newly designed coveralls was compared with the original one. Overall evaluation of functionally designed coveralls was appered to be positive and the image processing techiques were useful methology to quantify the amount of stress in this study.

• Journal of Biosystems Engineering
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• v.40 no.2
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• pp.102-109
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• 2015

Purpose: Slow manual harvesting of rain-fed chickpeas cultivated in fallow fields in developing countries have encouraged the design of a mechanical harvester. Methods: A tractor-pulled harvester was built, in which a modified stripper header detached pods from an anchored plant and a chain conveyor transferred material. The stripper harvester was redesigned to use: 1) the maneuverability of tractor-mounted frames, 2) the adaptability of floating headers, and 3) the flexibility of pneumatic conveyors. Results: A mobile vacuum conveyor, which was an innovator open system, was designed for the dilute phase transferring mode for both grain and material other than grain. A centrifugal fan transferred harvested material to a cyclone separator that settled harvested material in a grain tank 1 m high. The machine at the spot work rate of $0.42ha{\cdot}h^{-1}$ harvested chickpea pods equal to the output of 16.6 farm laborers. Conclusion: The low cost and reasonable projected purchase price are the advantages of the concept. Additionally, the shattering loss reduction confirms the feasibility of the prototype chickpea harvester for commercialization.

• Journal of electromagnetic engineering and science
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• v.2 no.2
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• pp.124-127
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• 2002

A RF tunable bandpass filter using dielectric resonators and varactor diodes is redesigned to improve the passband flatness. Since the tunable liters are generally of narrow bandwidth and the Q value of the varactor diode is usually very low, the passband flatness is strongly deteriorated by sizeable distortion loss. To remedy this problem, we construct modified Chebyshev type filter by use of network synthesis techniques. The key of modified Chebyshev type filter is the rearrangement of the passband poles to improve the passband flatness. To maintain the constant passband bandwidth, design techniques of input/output stage and coupling windows are also applied. Experimental results show that the passband flatness can be improved by purposed method without any additional RF amplitude equalizer.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.775-776
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• 2006

Based on the requirement of high power and efficiency in automobile systems, this paper describes an investigation for the optimum design of a permanent magnet reluctance motor(PRM), and then the characteristics of this kind of motor is compared with that of a interior permanent magnet(IPM) motor. The IPM of 4-pole with 6-slot is redesigned into a PRM, which has the same stator and different rotor structure with IPM. Through finite element analysis(FEA) and equivalent circuit method, the PRM has higher salient ratio, higher efficiency at high speed, and lower iron loss compared with IPM.

• The KSFM Journal of Fluid Machinery
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• v.2 no.1 s.2
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• pp.88-95
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• 1999

This paper introduces the part of efforts to develop a derivative type turboshaft engine from an existing baseline engine for multi-purpose helicopters aiming at 4000 kg of take-off weight for 10-12 passengers. As a first step in meeting the development goal of increasing the output power from 720 hp to 840hp with minimum modification, a two stage axial compressor was redesigned to obtain the higher pressure ratio by removing the inlet guide vane and increasing the chord length. As a result, a two stage axial compressor was designed to facilitate a flow rate of 3.04 kg/s, a pressure ratio of 2.01 and an adiabatic efficiency of $85\%$. Its performance tests were carried out and verification of test results and redesign are under progress. Aerodynamic and structural analyses of the preliminary design are mainly described in this paper.