• Korean Journal of Computational Design and Engineering
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• v.10 no.5
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• pp.375-379
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• 2005

Durability of rubber dust cover in the ball joint for automotive suspension parts is analyzed by FEM and compared with experimental data. Upper open area of ball joint is sealed by dust cover for preventing outflow of the lubricating oil and intrusion of send, dust, water, etc. This rubber cover undergoes repeated loadings such as tension and compression while the car is running. Analysis about rubber material needs to consider every kinds of nonlinearities arise in finite element analysis, which are geometric nonlinearity due to large displacement and small strain, materially nonlinearity and nonlinear boundary condition such as contact. The deformation behavior of dust cover is analysed by using the commercial finite element program MARC. In the study, this program could solve these kinds of nonlinear analysis accurately. Finite element model of dust cover is considered as 3-dimensional half model based on 2-dimensional axisymmetric model. Material property of rubber is modeled by Ogden model and input data for calculation takes form uniaxial tension test of rubber specimen. The final object of the study is obtaining the design specification of dust covers and the result of analysis should be a useful data to design of rubber cover.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.77-82
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• 2016

When drilling through Inconel 601 nickel-chromium-based alloys, a large amount of cutting oil is required to prevent tools from wear and fracturing due to heat buildup resulting from the high temperature resistance and toughness of this alloy. However, cutting oil supply has become a factor compromising the machining environment, and this has caused attention to shift to a more environmentally friendly cutting fluid supply system called minimum quantity lubrication (MQL). Our aim in this study was to find a more efficient drill processing method using MQL, and to verify its performance. To that end, we proposed a sealed cover, a step feed, and POSS-type cutting oil as measures to increase the effectiveness of MQL in view of the cutting force and tool wear, and established an improvement in efficiency using the proposed measures.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.1-8
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• 2018

In drilling Inconel 601, which is used for compressor cases in aircraft engines, a lot of cutting oil must be supplied. This prevents tools from wear and fracture due to the heat buildup resulting from the high-temperature resistance and toughness of this alloy. However, the cutting oil supply has compromised the machining environment. This has caused attention to shift to an environmentally friendly cutting fluid supply system called the Minimum Quantity Lubrication(MQL) system. The aim of this study was to find a more efficient drill processing method using MQL and to verify its performance. To that end, the properties of Inconel that make it difficult -to -drill were studied by a comparison with the drilling of SM45C. Specific factors (i.e., cutting force and tool wear) were examined in relation to the conditions in the MQL-based drilling system. Based on these results, a sealed cover and step feed were proposed as measures to increase the effectiveness of the MQL system. The efficiency of the proposed method was established.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.778-781
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• 2002

Durability of rubber dust cover in the ball joint for automotive suspension parts were analyzed by FEM and compared with experimental data. Upper open area of ball joint is sealed by dust cover for preventing outflow of the lubricating oil and intrusion of send, dust, water, etc. This rubber cover undergoes repeated loadings such as tension and compression while the car is running. Analysis about rubber material needs to consider every kinds of nonlinearities arise in finite element analysis, which are geometric nonlinearity due to large displacement and small strain, materially nonlinearity and nonlinear boundary condition such as contact. So in the study, the deformation behavior of dust cover was analysed by using the commercial finite element program MARC. This program could solve these kinds of nonlinear analysis accurately. Finite element model of dust cover is considered as 3-dimensional half model based on 2-dimensional axisymmetric model. Material property of rubber was modeled by Ogden model and input data for calculation takes form uniaxial tension test of rubber specimen, The final object of the study is obtaining the design specification of dust covers and the result of analysis should be a useful data to design of rubber

• Journal of Korea Foundry Society
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• v.27 no.3
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• pp.131-134
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• 2007

[ $SF_6$ ] gas that is used as a protective cover gas for Mg and Mg alloys during melting and casting has extremely high greenhouse effect. CaO added Mg alloys could maintain their original mechanical properties and original abilities such as fluidity and hot tearing susceptibility. The ignition temperature increased with increasing CaO addition under ambient atmosphere and nitrogen atmosphere. The minimum amount of $SF_6$ gas decreased by 0.13 wt%CaO added AZ91D Mg alloy in the sealed condition.

• Restorative Dentistry and Endodontics
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• v.31 no.4
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• pp.282-289
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• 2006

The purpose of this study was to compare the ability of three resin surface sealants to prevent microleakage in Class V composite resin restorations. Forty Class V cavities with the occlusal margin in enamel and gingival margin in dentin were prepared on the buccal surfaces of sound extracted molars, and restored with composite resin. Restorations were randomly assigned into one of four equal groups (n = 10): a control group, without resin sealing, and three experimental groups in which margins were sealed with Fortify Plus, Biscover and Permaseal, respectively. Specimens were thermocycled, immersed in a 2% methylene blue solution for 4 hours, sectioned longitudinally, and observed the leakage at the occlusal and gingival margins. The result was analyzed using Kruskal-Wallis test, Mann-Whitney test and Wilcoxon signed rank test. In conclusion, the ability to reduce microleakage at occlusal margins was similar in all of three sealants. However at gingival margin, it depended on the type of used resin surface sealant. At gingival margin. control and Fortify Plus group showed statistically higher microleakage than PermaSeal group. and Fortify Plus group also showed higher microleakage than BisCover group (p < 0.05).

• Restorative Dentistry and Endodontics
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• v.45 no.1
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• pp.12.1-12.8
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• 2020

Objectives: The aim of this in vitro study was to evaluate the microhardness and surface roughness of composite resins before and after tooth bleaching procedures. Materials and Methods: Sixty specimens were prepared of each composite resin (Filtek Supreme XT and Opallis), and BisCover LV surface sealant was applied to half of the specimens. Thirty enamel samples were obtained from the buccal and lingual surfaces of human molars for use as the control group. The surface roughness and microhardness were measured before and after bleaching procedures with 35% hydrogen peroxide or 16% carbamide (n = 10). Data were analyzed using 1-way analysis of variance and the Fisher test (α = 0.05). Results: Neither hydrogen peroxide nor carbamide peroxide treatment significantly altered the hardness of the composite resins, regardless of surface sealant application; however, both treatments significantly decreased the hardness of the tooth samples (p < 0.05). The bleaching did not cause any change in surface roughness, with the exception of the unsealed Opallis composite resin and dental enamel, both of which displayed an increase in surface roughness after bleaching with carbamide peroxide (p < 0.05). Conclusions: The microhardness and surface roughness of enamel and Opallis composite resin were influenced by bleaching procedures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1446-1455
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• 2016

The recent increase of fresh farm products, hazardous cargos, and high-priced goods in marine transportation has caused an increased demand of cargo owners and shipping companies with regard to the monitoring of the location and state of cargo. To meet this increase, numerous technologies are being studied for the monitoring of the cargo state. Cargo containers on a ship are loaded on a ship's deck and in a ship's hold, which is located under the deck. However, Since the developed technologies mostly transfer the container status information that collected by mobile communication, it costs a lot to install communication infrastructure on ship. And the ship's hold is completely sealed with a cover, and communication with the reader positioned at the ship's bridge is difficult. Therefore, most existing studies on container monitoring on ships have focused on the monitoring of containers loaded on a ship's deck. Accordingly, this study suggested system configuration for the monitoring of containers in a ship's hold using IP-RFID technology. The suggested system configuration was tested on an actual ship under navigation, and the test results are given in this study. The test results verified that the monitoring of containers in a ship's hold using IP-RFID technology is effective.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1121-1121
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• 2001

A previous study (Berzaghi et al., 2001) evaluated the performance of 3 calibration methods, modified partial least squares (MPLS), local PLS (LOCAL) and artificial neural networks (ANN) on the prediction of the chemical composition of forages, using a large NIR database. The study used forage samples (n=25,977) from Australia, Europe (Belgium, Germany, Italy and Sweden) and North America (Canada and U.S.A) with reference values for moisture, crude protein and neutral detergent fibre content. The spectra of the samples were collected using 10 different Foss NIR Systems instruments, only some of which had been standardized to one master instrument. The aim of the present study was to evaluate the behaviour of these different calibration methods when predicting the same samples measured on different instruments. Twenty-two sealed samples of different kind of forages were measured in duplicate on seven instruments (one master and six slaves). Three sets of near infrared spectra (1100 to 2500nm) were created. The first set consisted of the spectra in their original form (unstandardized); the second set was created using a single sample standardization (Clone1); the third was created using a multiple sample procedure (Clone6). WinISI software (Infrasoft International Inc., Port Mathilda, PA, USA) was used to perform both types of standardization, Clone1 is just a photometric offset between a “master” instrument and the “slave” instrument. Clone6 modifies both the X-axis through a wavelength adjustment and the Y-axis through a simple regression wavelength by wavelength. The Clone1 procedure used one sample spectrally close to the centre of the population. The six samples used in Clone 6 were selected to cover the range of spectral variation in the sample set. The remaining fifteen samples were used to evaluate the performances of the different models. The predicted values for dry matter, protein and neutral detergent fibre from the master Instrument were considered as “reference Y values” when computing the statistics RMSEP, SEPC, R, Bias, Slope, mean GH (global Mahalanobis distance) and mean NH (neighbourhood Mahalanobis distance) for the 6 slave instruments. From the results we conclude that i) all the calibration techniques gave satisfactory results after standardization. Without standardization the predicted data from the slaves would have required slope and bias correction to produce acceptable statistics. ii) Standardization reduced the errors for all calibration methods and parameters tested, reducing not only systematic biases but also random errors. iii) Standardization removed slope effects that were significantly different from 1.0 in most of the cases. iv) Clone1 and Clone6 gave similar results except for NDF where Clone6 gave better RMSEP values than Clone1. v) GH and NH were reduced by half even with very large data sets including unstandardized spectra.