• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3118-3126
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• 1994

This paper describes the use of the concept of (relative) entropy for effective characterization of the amplitude and the frequency distributions of the surface profile formed in machining operation. For this purpose, a theoretical model for surface texture formation in turning operation is developed first. Then, the concept of (relative) entropy is reviewed and its effectiveness is examined based on the simulation and experimental results. The results also suggest that under random tool vibration the effect of the geometrical factors on the surface texture formation can be successfully decomposed and therefore, identified by applying the concept of (relative) entropy.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1998.12a
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• pp.261-268
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• 1998

• Journal of the Korean Society of Clothing and Textiles
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• v.24 no.6
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• pp.810-818
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• 2000

The purpose of this study was to analyze the effect of geometrical structure on the moisture transport properties of nonwoven batting materials. Two types of nonwovens were used such as single and double layered nonwovens. Steady and dynamic state water vapor transport properties were measured by absorption, evaporation and cobaltous chloride method respectively. The results of this study were as follows: 1) Geometrical structure affected water vapor evaporation, but there were no differences between single and double layered nonwovens in moisture absorption. Thickness and air permeability were influencing factor on water vapor transport rate. 2) Directionality of double layered nonwoven was observed both in steady and dynamic state moisture transport. There were differences between upper and lower layer of double layered nonwoven both in moisture absorption rate and color change by cobaltous chloride method. 3) In dynamic state of water vapor transport rate, single layered nonwoven reached more rapidly at the established relative humidity. It was confirmed that geometrical structure affected water vapor evaporation and hydrophilicity of fiber affected moisture absorption because there were much more water vapor transport rate by evaporation than absorption within the same period of time.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.773-777
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• 1999

Scale-up experiments for hydrolysis of beef tallow, fat, and palm kernel with lipase derived from Candida cylindracea were carried out in 1-1, 100-1, and 10,000-1 reactors. The optimum agitation speed for the hydrolysis of the 1-1 reactor was investigated and found to be 350rpm, and this was a basis for the scale-up of agitation speed. The hydrolysis system in this work was the oil-water system in which the hydrolysis seems to process a heterogeneous reaction. An emulsion condition was the most important factor for determining the reaction rate of hydrolysis. Therefore, the scale-up of agitation speed was performed by using the power n = 1/3 in an equation of the rules of thumb method. The geometrical similarity for scaling-up turned out to be unsatisfactory in this study. Thus, the working volume per one agitator was used for the scale-up. In the case of scale-up from a 1-1 reactor to a 100-1 reactor, the hydrolysis of palm kernel was very much scaled-up by initiating the rules of thumb method. However, the hydrolysis of fat and beef tallow in a 100-1 reactor was a little higher than that of the 1-1 reactor because of the difference of geometrical similarity. The scale-up of hydrolysis from the 100-1 reactor to the 10,000-1 reactor was improved compared to that of the 1-1 to 100-1 reactor. The present results indicated that the scale-up of hydrolysis in the oil-water system by the rules of thumb method was more satisfactory under the condition of geometrical similarity. Even in the case where geometrical similarity was not satisfactory, the working volume per one agitator could be used for the scale-up of a heterogeneous enzyme reaction.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.293-296
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• 2007

This study investigated the out-of-plane elastic buckling load and effective length factor of X-bracing system. The members of X-bracing system which are studied in this paper are rigidly attached to the structure at their end connections, and are pinned or rigidly connected at their point of intersection. The effective length factors are derived for the general case where the tension and compression brace have different material and geometrical properties.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1267-1268
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• 2013

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.237-240
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• 1997

This paper is to arrange systematically the geometrical & physical data for real ships and to develop the graphic user interface program for initial hull design using NFHFD, which save the distributed information about hull form database and can output multi-variables.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.290-296
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• 2012

Cold-rolled carbon steel sheets are commonly used in railroad car or commercial vehicles such as the automobile. These are mainly fabricated by spot welding which is a kind of electric resistance welding. But fatigue strength of spot welding joint is lower than that of base metal due to high stress concentration at nugget edge of the spot welded part. And fatigue strength of them is especially influenced by not only geometrical and mechanical factors but also welding conditions of the spot welded joint. So for fatigue design of gas welded joints such as TS-type joints, it is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of spot welded joints. And also, the influence of the geometrical parameters of spot welded joints on stress distribution and fatigue strength must be evaluated. And analysis approach for fatigue test using design of experiment are evaluated optimum factor in TS-type welded joint and geometrical parameters of materials. Using these results, that factors applied to fundamental information for automation of fatigue design.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.51-57
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• 2001

In order to estimate attenuation characteristics, nonparametric model is used. Evaluation of this model requires suites of average spectral amplitude data as a function of distance without adopting any assumed parametric forms. Values of Quality factor, Q were estimated for individual frequencies by matrix inversion of S wave amplitude spectra for 21 records of 8 small and intermediate earthquakes (2.7$(1/r)^{1/2}$. The best models for 1/Q values were found to be 0.000453+0.001851/f and 0.000451+0.009261/f, respectively. This results can be compared to the conventional functional form of Q=$af^{b}$ and be used to estimate source spectra and site response.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.243-245
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• 2004

Failure mechanisms of weldments under fatigue loads are interpreted that multiple collinear surface cracks initiating along weld toe propagate under the mutual interaction and coalescence of adjacent two cracks. To estimate fatigue crack propagation life for these weldments, the stress intensity factors of the multiple surface cracks have to be calculated which are influenced strongly by the geometrical complexity of weld toes and attachments. The Ak-factors derived by a parametric study can be introduced for the effective calculation of the stress intensity factors taking into account the geometrical complexity. The fatigue life was estimated by using the Ak-factors and the method considering the propagation mechanisms of the multiple surface cracks. The estimated values showed a good agreement with the measured fatigue life experimentally.