• Journal of the Korean Ceramic Society
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• v.39 no.11
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• pp.1048-1054
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• 2002

When forming the ceramic body with plastic mass, it is needed that a quantitative testing method for plasticity, not only to evaluate the plasticity of a body, but also to control it within limits. Although many testing instruments were introduced, but no handy testing instrument for the plasticity quantitatively has been developed. In this study, modified vicat needle was designed to handily evaluate the plasicity of extruding bodies for honeycomb. The plasticity of three plastic masses was tested with this equipment. Columned needle with 2 mm diameter was adopted to measure the resistance for deformation and spherical needle with 9.5 mm diameter was adopted to measure the amount of deformation before cracking. The plasticity of three tested bodies were clearly distinguished quantitatively each other and the testing results were helpful to evaluated the workability of theses bodies. Probably, it is possible to evaluate the plasticity of various ceramic bodies with this apparatus, if suitable diameters of columns and spheres are selected.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.404-413
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• 2013

In the present study, a towed underwater particle image velocimetry (PIV) system was validated in uniform flow and used to investigate the free-surface effects on the turbulent wake of a simple surface-piercing body. The selected test model was a cylindrical geometry formed by extruding the Wigley hull's waterplane shape in the vertical direction. Due to the constraints of the two-dimensional (2D) PIV system used for the present study, the velocity field measurements were done separately for the vertical and horizontal planes. Using the measured data at several different locations, it was possible to identify the free-surface effects on the turbulent wake in terms of the mean velocity components and turbulence quantities. In order to provide an accuracy level of the data, uncertainty assessment was done following the International Towing Tank Conference standard procedure.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.3
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• pp.69-75
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• 2010

A hollow flanged spindle is generally used for the assembly of the driving shaft in some vehicles. This part has conventionally been manufactured by both hot forging and machining process, in which case a circular billet is hot-forged into a flanged spindle blank and then its central part is machined for hollow. Therefore, the development of a new forming technology without further machining processes has strongly been in demand. In this study, a new compound forging process of the hollow flanged spindle was proposed through the finite element simulation. By the proposed compound forging process, both extruding of the spindle body part and piercing for the hollow inside it can be performed at the same time. Metal flow patterns, forging defects and forging forces were investigated through the finite element simulation results.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.173-180
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• 2004

The tread pattern of a tire has an important effect on tire performances such as handling, wear, noise, hydroplaning and so on. However, a finite element analysis of a patterned tire with detailed tread blocks has been limited owing to the complexity of making meshes for tread blocks and the huge computation time. The computation time has been shortened due to the advance in the computer technology. The modeling of tread blocks usually requires creating a solid model using a CAD software. Therefore it is a very complicated and time-consuming job to generate meshes of a patterned tire using a CAD model. A new efficient and convenient method for generating meshes of a patterned tire has been developed. In this method, 3-D meshes of tread pattern are created by mapping 2-D meshes of tread geometry onto 3-D tread surfaces and extruding them through tread depth. Then, the tread pattern meshes are assembled with the tire body meshes by the tie contact constraint. Residual aligning torque and frictional energy are calculated by using a patterned tire model and compared to the experimental results. It is shown that the calculated results of a patterned tire model are in a good agreement with the experimental ones.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1765-1772
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• 2002

Three experiments were conducted to determine the feed processing method best suited for early and conventionallyweaned pigs, and to investigate the effects of different extrusion temperatures on ileal digestibility of amino acids in diets containing different protein sources. In exp.1, a total of 108 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 24 d of age and 7.60 kg average body weight) were alloted on the basis of sex, weight and ancestry to three treatments in a randomized complete block design. Feed processing methods used were mash (M), simple pellet (SP), and expanded pellet (EP). In exp. 2, a total of 96 pigs (Landrace${\times}$Yorkshire${\times}$Duroc; 14 d of age) were allotted on the basis of sex, weight, and ancestry to three treatments in a randomized complete block design. Diets were mash (M), expanded pellet (EP), and expanded pellet crumble (EPC). In exp. 3, a study was designed to investigate the effect of different extrusion temperatures (100, 120, and $140^{\circ}C$) over the control (untreated) on the ileal digestibility of amino acids in diets containing protein sources such as spray-dried plasma protein (SDPP), whey protein concentrate (WPC), and fish meal (FM). Results in exp.1 showed that ADG, ADFI and the F/G ratio of pigs fed the SP diet were improved (p<0.05) compared with those fed the M or the EP diets, but the digestibility of nutrients was not different (p>0.05) among the treatments. In exp. 2, pigs fed expanded pellet treatments (EP or EPC) had a significantly improved (p<0.05) F/G ratio compared to the pigs fed the M diet which was primarily attributed to the significant reduction (p<0.05) in ADFI, but the overall growth rate of pigs fed expanded pellet diets was not improved. In exp. 3, there was a significant interaction effect (p<0.05) between the extrusion temperature and protein source on the ileal digestibility of amino acids. With an extrusion temperature of $100^{\circ}C$, the ileal digestibility of Lys, Val, Gly and Ser was significantly lower in the diet containing WPC compared to the diet containing SDPP. Increasing the temperature to $120^{\circ}C$ led to significant differences (p<0.05) in the digestibility of Thr and Tyr between diets containing WPC and SDPP. Regardless of extrusion temperatures, the weaned pigs' diet containing either SDPP or FM had significantly higher Lys, Phe, Thr, Val, and Gly digestibility relative to the WPC diet. Results of the present study suggest that simple pelleting of diets containing protein sources such as whey protein concentrate, spray-dried plasma protein and fish meal would be better than the extruded or expanded pellet diets. Extruder or expander processing of weaned pigs' feed could reduce palatability and ileal digestibility of several amino acids and therefore may be responsible for a negative growth response in weaned pigs.