• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.2
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• pp.91-99
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• 1998

This paper presents a methodology for identifying the cutter runout geometry in end milling process. Cutter runout is common but undesirable phenomenon in multi-tooth machining because it introduces variable chip loading to insert which results in a accelerated tool wear. amplification of force variation and hence enlargement vibration amplitude From understanding of chip load change kinematics, the analytical cutting force convolution model was formulated as the angular domain convolution model was formulated as the angular domain convolution of three dynamic cutting force component functions. By virtue of the convolution integration property, the frequency domain expression of the local cutting forces and the chip width density of the cutter. Experimental study is presented to validate the analytical model. This study provides the in-process monitoring and compensation of dynamic cutter runout to improve machining tolerance and surface quality for industrial application.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.239-242
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• 2012

Overlay complete dentures are simple, reversible and economical treatment modality for patients with congenital or acquired disorders that severely affect the tooth development. It satisfies both the esthetic and functional demands where the extraction of teeth is not generally indicated. In pediatric patients, the overlay dentures establish a relatively stable occlusion that improves patient's tolerance to the future treatment procedures for worn dentition. This clinical report highlights the imperative need of appropriate treatment strategy and application of maxillary and mandibular overlay dentures in a pediatric patient who suffered from congenitally mutilated and worn dentition.

• Asian Journal of Turfgrass Science
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• v.17 no.1
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• pp.19-33
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• 2003

The objective of this study was to evaluate the effects of crumb rubber recycled from used tires as a soil incorporation and topdressing materials on a trafficked Korean lawngrass‘Zenith’(Zoysia japonica). In Exp 1, incorporation treatments included three particle sizes (PS: coarse =4∼6.35 mm, medium =2∼4 mm, and One : less than 2 mm in diameter) and two incorporation rate (IR: 10 and 20%). Wear treatments were applied 30 passes per day by compactor weights being 60 kg with soccer shoes. Topdressing treatments included three PS and two topdressing depth (TD: 5 and 10 mm). Wear treatments were the same as described in Exp 1. In Exp 1, the treatment with medium PS+IR 20 resulted in the tendency to have high total clipping yield. There was no significant difference in clipping yield, turfgrass visual color, coverage, and root length among the treatments. Compared to control, tissue Zn levels increased about 6.5-fold by the treatments. The treatment with fine PS +IR 20 caused a less peak deceleration than coarse PS +IR 10. Total porosity, air-filled porosity, and capillary porosity increased with fine PS +IR 20. In Exp 2, compared to controls, however, there was a difference in turfgrass visual color after the termination of traffic treatment. There was no difference in root length. The treatment with fine PS + TD 10 resulted in the highest total clipping yield. As a result of soil physical analysis, soil penetration resistance was reduced by the treatments. The treatment with coarse PS resulted in a less peak deceleration than fine PS. In conclusion, turfgrass growth was increased by crumb rubber incorporation which enhanced soil physical properties. The crumb rubber topdressing was able to cushion the crown tissue area while still providing a smooth and uniform surface, improve overall turfgrass quality, and reduce compaction.

• Journal of KSNVE
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• v.11 no.1
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• pp.125-131
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• 2001

There is a clearance between the parts of a machine due to design tolerance, manufacturing error, wear, looseness, or misalignment. If the clearance is large, the vibration and noise of the machine is generally large. Therefore, the analysis on the nitration and noise of a machine can tell the clearance of the machine, which reveals the condition of the machine, i.e., the existence of faults and the safety of the machine. The investigation of this kind of research should be on the basis of experimental results. A link mechanism with a clearance at a joint between the coupler and locker is made for the investigation of the condition monitoring of a machine due to clearance. The vibration and sound are measured from the link driving system during the operation. The signals are clarified using line enhancement technique. The noise removed signals are used to develop the dynamic model of the system for a model based fault diagnosis. Also this study showed that the clarified signals can be used for the calculation of the joint forces between the coupler and rocker and for the correlation between the vibration and sound levels and the clearance sizes.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.51-55
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• 2005

This study addresses the contamination sensitivity test of a typical fuel pump for an automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of a fuel pump on specific contaminant particle sizes so that an optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of the fuel pump is measured under the experiments of various contaminants size ranges of ISO test dust up to $80\;{\mu}m$. The fundamental theory of contamination sensitivity is introduced and the contamination sensitivity coefficients are estimated using the experimental data. Maximum contamination sensitivity coefficient of $5\chi\;10^{-6}\;L/min{\cdot}Ea$ is found in the contaminant size range of $40\;{\mu}m\~50\;{\mu}m$. The magnified picture of the surface of vane disc reveals that the abrasive wear is the principal cause of discharge flow rate degradation. Hence, this study reveals that a high efficiency filter for contaminant particles especially in the size range of $30\;{\mu}m\~70\;{\mu}m$ especially should be used to maintain the service life of the fuel filter.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.102-108
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• 2004

This study addresses the contamination sensitivity test of a typical fuel pump for automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of fuel pump on specific contaminant particle sizes so that optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of fuel pump was measured under the experiments of various contaminants size ranges of ISO test dust up to 80${\mu}{\textrm}{m}$. The fundamental theory of contamination sensitivity was introduced and the contamination sensitivity coefficients were estimated using the experimental data. Maximum contamination sensitivity coefficient of $5{\times}10^{-6}$ L/minㆍEa was found on the contaminant size range of 40${\mu}{\textrm}{m}$∼50${\mu}{\textrm}{m}$. The magnified picture of the surface of vane disc revealed that the abrasive wear was the principal cause of discharge flow rate degradation. Hence, this study revealed that high efficiency filter on the contaminant particle size range of 30${\mu}{\textrm}{m}$∼70${\mu}{\textrm}{m}$ especially should be used to maintain the service lift of the fuel filter.

• The Research Journal of the Costume Culture
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• v.21 no.3
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• pp.431-439
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• 2013

This study aims to give practical help to the pattern making of baggy pants produced in large quantity from industrial fields. The functionality of crotch part is a key element to decide wear sensation and comfort of pants as having direct influence on movements of legs in pattern designing of baggy pants. The industrial patterns of baggy pants in various styles that are released currently in Korea were collected and a comparative analysis was conducted on them for the thesis. First, samples of men baggy pants were collected from three different brands and compared the completion sizes. Secondly, it studied the most appropriate patterns as quantifying the appropriateness of movements through fitting tests. Finally, the study verified the differences of visual images by surveys of professional groups. The conclusions obtained from this research are as follows. In terms of aesthetic attribute among the three brands, A baggy pants, which had a small size tolerance, were the most appropriate. Meanwhile concerning the appropriateness of movement, B baggy pants were shown to be the most appropriate. This reveals explicitly the problem of aesthetic attribute and functionality, which are always in conflict during the pattern design. It is necessary to develop patterns and establish a measurement system that may satisfy both of these factors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.464-469
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• 2019

Tapered roller bearings are used widely in vans, trucks, and trains because they can support the vehicle in a stable manner even under a heavy load. The cage of a tapered roller bearing maintains the gap between the rollers, which prevents friction wear and suppresses heating. If the cage is severely deformed due to resonance, the roller may not be able to roll smoothly and even leave the cage. Consequently, it is very important to analyze the dynamic characteristics of the cage for reliable performance of a bearing. The cage essentially has geometrical tolerance in the manufacturing process. In this paper, the effects of those geometrical imperfections on the dynamic characteristics of the cage were investigated. As a result, natural frequency separation occurred near the natural frequency of the ideal cage due to geometrical imperfections. In addition, the interval was proportional to the magnitude of the geometric error, and the interval increased with increasing mode number.

• Composites Research
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• v.20 no.5
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• pp.49-55
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• 2007

Nanocomposite blade for dicing semiconductor wafer is investigated for micro/nano-device and micro/nano-fabrication. While metal blade has been used for dicing of silicon wafer, polymer composite blades are used for machining of quartz wafer in semiconductor and cellular phone industry in these days. Organic-inorganic material selection is important to provide the blade with machinability, electrical conductivity, strength, ductility and wear resistance. Maintaining constant thickness with micro-dimension during shaping is one of the important technologies fer machining micro/nano fabrication. In this study the fabrication of blade by wet processing of mixing conducting nano ceramic powder, abrasive powder phenol resin and polyimide has been investigated using an experimental approach in which the thickness differential as the primary design criterion. The effect of drying conduction and post pressure are investigated. As a result wet processing techniques reveal that reliable results are achievable with improved dimension tolerance.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.329-335
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• 2014

This study was performed to study characteristics of new zoysiagarass cultivar 'Green Ever' (Plant Variety Protection Application no. 2014 - 02). 'Green Ever' was developed by selection breeding among 100 native zoysiagrasses collected in South Korea. 'Green Ever' showed specific bands (1.48 kb with OPC14 and 1.05 kb with OPD5) which were distinct from 'Anyang Joonggi' or 'Dongrae Koryogi' in RAPD analysis. 'Green Ever' was classified as Z. matrella in morphological evaluations including plant height ($6.8{\pm}0.5cm$), leaf width ($2.0{\pm}0.1mm$), height of lowest leaf ($1.9{\pm}0.1cm$) and seed length ($3.0{\pm}0.1mm$), which was similar with morphological characteristics of 'Dongrae Koryogi'. Turf quality, shoot density and chlorophyll content of 'Green Ever' were higher than them of 'Anyang Joonggi' and 'Dongrae Koryogi' under intensive management such as fairway on golf course, especially shoot densities of 'Green Ever' were excellent higher than 'Anyang Joonggi' and 'Dongrae Koryogi' during experimental periods. It could be extensively used in fairway, teeing ground of golf courses and landscape garden after further study about various environmental adaptabilities such as winter kill, wear tolerance etc.