• Tribology and Lubricants
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• v.21 no.6
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• pp.272-277
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• 2005

Continuously variable transmission (CVT) of toroidal type has a elliptical shape of contact zone under the elastohydrodynamic lubrication (EHL) condition, where the power is transmitted only by shearing the lubricant. Due to the small contact area of elliptical shape, the traction of the shear behaviors of lubricant over the contact zone is under extremely high contact pressure over 1.0GPa. During the power transmission by shearing the fluid, many kinds of mechanical movements occur such as squeezing, sliding, rolling and spin. Among the movements, the spin effect that is the most undesirable contact behavior in transmitting the power frequently makes significant abnormal wear damage. In this work, the analysis of elliptical contact of EHL with spin effect is performed, which will give very useful information to understand the traction behaviors in toroidal type of CVT system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1440-1443
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• 2004

Shearing including punching, blanking, trimming, slitting, etc is one of the most frequently used processes in sheet metal manufacturing. It has been widely used for manufacturing autobody, electronic components, aircraftbody, etc. In this paper, it has been researched by the experiment to examine the effect of burr height corresponding to die clearance, cutting angle, tool sharpness, etc. This paper presents the experimental results with using Al alloy sheet.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.5
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• pp.80-86
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• 2000

The Tailor Welded Blanks(TWB) are using various materials (different thickness, strength and different materials) can be welded together prior to the forming process. Therefore, TWB applications have become little by little important in automobile industries, because it has more light weight and process reduction. A burnish area is very important for TWB using laser welding. In this paper, evaluated failure criterion, effect of clearance and distance of between pad and punch by computer simulation. We used element separation method for fracture. And applied a plastic strain to failure criterion. According to the analysis results, we obtain failure criterion, when plastic strain is 2.0. The burnish area and clearance were inverse proportional.

• Food Engineering Progress
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• v.13 no.1
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• pp.70-73
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• 2009

The yield stress of stirred yogurt was measured by the vane viscometer at different pre-shearing conditions, such as pre-shear speed, pre-shear time, and wait time, and temperature (12-38${^{\circ}C}$). The yield stress ranged from ~17.6 to 10 Pa and from 34.2 to 11.9 Pa, depending on the pre-shearing conditions and temperature, respectively. The preshear speed and the wait time significantly affected the yield stress. The temperature dependence of the yield stress was described by the Eyring's kinetic model. The linear function of the temperature on the yield stress was limited at the 22${^{\circ}C}$, and at the above 22${^{\circ}C}$, the yield stress was maintained to be a constant (~12.5 Pa).

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1106-1109
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• 2001

This experiment was conducted with 30 adult wool producing Angora rabbits of either sex, to evaluate the effect of replacing soyflakes (SF), on equal protein basis, with low gossypol containing cottonseed meal (CSM) either alone or in combination with lysine and methionine; on the biological performance, total wool yield, wool yield per shearing, wool characteristics and mortality. Three experimental mash diets were prepared by incorporating SF (6%) as standard / control protein source $(T_1)$ and CSM (9%) as test protein source ($T_2$ and $T_3$). In $T_3$, amino acids-lysine and methionine (0.1 % each) were added. Animals were given the experimental diets about $150g{\cdot}day^{-1}{\cdot}head^{-1}$, for a period of 225 d or three shearing, and ad libitum Kudzu-vines. No significant effect of $T_2$ or $T_3$, on the body weight gain, total wool yield, wool yield per shearing and wool characteristics, was observed compared to $T_1$. However, the digestibility of dry matter, crude fibers, ether extract, acid detergent fibers, neutral detergent fibers, cellulose and hemicellulose was significantly (p<0.05) depressed in CSM based diets. Mortality of about 20% was recorded in $T_2$ and $T_3$, but not related to the addition of CSM or gossypol toxicity. More studies are needed to standardize the safe level of CSM, duration of safe feeding of CSM, and level of amino acids supplementation in CSM based diets.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2885-2889
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• 2007

In this study, the effect of particle aggregation on dynamic response time of Electrorheological (ER) fluid is investigated. The particle aggregation time is defined as the time interval between the application of the field and the formation of the first chain bridging the two electrodes. The dynamic response times of an ER fluid sheared between two concentric cylinders have been obtained under two different experimental conditions: the one is that the electric field is induced before shearing, and the other is that the electric field is induced after shearing. From the difference between two response times, the particle aggregation times are determined under various electric fields and shear rates. The experimental results show that the aggregation rate is decreased with an increase of shear rate, while electric field has little effect on it. Therefore, it is verified that the hydrodynamic force hinders the formation of chain-like structures.

• Journal of the Korean Wood Science and Technology
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• v.42 no.1
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• pp.34-40
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• 2014

The effect of neonicochid type wood preservatives on adhesive properties of resorcinol-formaldehyde resin for laminated wood manufacture was examined. By the previous studies, it was verified that the neonicochid type preservative has a high termite-proofing and anti-mold effectiveness. Commercial ACQ (ammoniacal copper quaternary compounds) and CUAZ (copper azol compounds) were used as comparison preservatives of effects on adhesive properties. The wood specimens used japanese red pine (Pinus densifrora) after application with preservatives and then bonded with resorcinol-formaldehyde resin. Adhesive properties were evaluated by shearing strength of adhesive bond and wood failure to dry condition or after accelerated aging test. Of all laminated woods, the wood specimens spread with ACQ or CUAZ showed the lowest shearing strength of adhesive bond. We estimated that the decrease of shearing strength was caused by copper in the ACQ or CUAZ preservatives. On the application of the neonicochid type preservatives, the wood specimens showed the highest shearing strength even after accelerated aging test. From these results, it is concluded that the copper-free neonicochid type preservative not affected the curing of resorcinol-formaldehyde resin.

• Journal of the Korean earth science society
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• v.42 no.2
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• pp.164-174
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• 2021

The study examines the shearing and crushing characteristics of land-derived subaqueous granular materials in a gravel-bed river. A series of large-sized ring shear tests were performed to examine the effect of shear time and shear velocity on the shear stress characteristics of aquarium gravels with a 6-mm mean grain size. Three different shear velocities (i.e., 0.01, 0.1, and 1 mm/sec) were applied to measure the shear stress under the drained (long-term shearing) and undrained (short-term shearing) conditions. Different initial shear velocities, i.e., 0.01→0.1→1 mm/sec and 0.1→0.01→1 mm/sec, were considered in this study. The test results show that the grain crushing effect is significant regardless of drainage conditions. The shear stress of coarse-grained materials is influenced by initial shear velocities, regardless of the drainage conditions. In particular, particle breakage increases as grain size increases. The shearing time and initial shear velocity are the primary influencing factors determining the shear stress of gravels. The granular materials may be broken easily into particles through frictional resistance, such as abrasion, interlocking and fracture due to the particle-particle interaction, resulting in the high mobility of granular materials in a subaqueous environment.

• Journal of the Korean Geotechnical Society
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• v.20 no.5
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• pp.5-16
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• 2004

This paper presents the modeling of geosynthetic-reinforced compacted soils and discusses the reinforcement effect arising from confining the dilatancy deformation of the soil by geosynthetics. A series of compressive shear tests for compacted sandy soil specimens wrapped by geosynthetics are carried out by quantitatively examining the geosynthetic-reinforcement effect, occurring from a confinement of the dilative deformation in compacted soils during shearing. In the test, the initial degree of compaction is changed for each series of sandy soil specimens so that each series has different degree of dilatancy characteristics. Herein, the axial forces working on the geosynthetics so as to prevent dilative deformation of compacted soils during shearing are measured. Furthermore, the elasto-plastic modeling of compacted soils and a rational determination procedure for input parameters needed in the elasto-plastic modeling are presented. And to describe the irreversible deformation characteristics of compacted soils during shearing, the subloading yielding surface (Hashiguchi (1989)) to the elasto-plastic modeling is introduced. Finally, the elasto-plastic finite element simulation is carried out and the geosynthetic-reinforcement effect is discussed.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.37-46
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• 2004

This paper presents the modeling of geosynthetic-reinforced soils and discusses the reinforcement effect arising from confining the dilatancy deformation of the soil by geosynthetics. A series of compressive shear tests for compacted sandy soil specimens wrapped by geosynthetics are carried out by quantitatively examining the geosynthetic-reinforcement effect, and it occurred from the confinement of the dilative deformation of compacted soils during shearing. In the test, the initial degree of compaction is changed for each series of sandy soil specimens so that each series has different degree of dilatancy characteristics. Herein, the axial forces working to the geosynthetics so as to prevent dilative deformation of compacted soils during shearing are measured. Furthermore, the elasto-plastic modeling of compacted soils and a rational determination procedure of input parameters needed in the elasto-plastic modeling are presented. In this paper, the subloading yielding surface(Hashiguchi(1989)) is introduced to the elasto-plastic modeling which could describe the irreversible deformation characteristics of compacted soils during shearing. Finally, the elasto-plastic finite element simulation is carried out and the geosynthetic-reinforcement effect is discussed.