• Textile Coloration and Finishing
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• v.16 no.1
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• pp.5-9
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• 2004

This research surveys the threadline instability on the belt texturing machine according to the 1st heater temperature, draw ratio and velocity ratio. the threadline instability to the time, which is called surging phenomena, is analysed with variations of draw ratio and velocity ratio. In addiction, the surging phenomena is investigated with the variation of the untwisting tension and false twist mechanism on the belt texturing machine. The breaking strain, modulus and yam unevenness of the DTY along the yarn length are measured and analysed with the surging phenomena which is due to untwisting tension variation on the threadline according to the draw ratio, 1st heater temperature and velocity ratio.

• Textile Coloration and Finishing
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• v.20 no.1
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• pp.28-35
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• 2008

Texturing is the process of including a characteristic of a natural fiber in a synthetic fiber. The most common method of it the false twist texturing. Nylon textured yarn is primarily manufactured by the disk type. The major process parameters or the disk type false twist machine ratio, disk/yarn, and heater temperature. This study therefore investigated the effects of false twist texturing, especially speed and draw ratio, on the physical properties of nylon textured yarn. The increase of speed was proportional to the increase of unwinding tension, which could reduce the production efficiency by elevating the tension affecting to fiber during the process. In addition, the increase of speed was inversely proportional to the increase of crimp rigidity of nylon textured yarn. Draw ratio was proportionally increased with the increase of tenacity and the reductions of fineness and elongation, showing the influence or draw ratio to the ultimate physical properties of textured yarn.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.45-59
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• 2002

Evaluation of the mechanical properties of Bi-2223/Ag HTS tapes was carried out by the tension and bending tests. Most of the Bi-2223/Ag tapes retained critical current up to 10 kgf/mm$_2$ axial tension stress, and 0.2% tension strain at room temperature. Applied tension strain exceeding 0.3% in superconducting tapes at 77 K leaded to rapid degradation of the critical current. It was observed that the more filaments, the better axial tension property at 77 K, self-field The influence of bending strain on critical current degradation was revealed to be less sensitive for Bi-2223/Ag HTS tapes with a more number of filaments and higher silver ratio.

• Journal of the Korean Wood Science and Technology
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• v.21 no.4
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• pp.73-78
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• 1993

Crystal structure of tension, opposite and lateral wood of Platanus orientalis L. were analysed in some aspects of crystallinity index, crystallite size, d-spacing of (200) and (004), and integrated intensity ratios with X-ray diffraction method. Crystallinity index and crystallite width in tension wood appeared somewhat larger than opposite or lateral wood. However, d-spacing and integrated intensity ratios were nearly identical irrespective of tension, opposite, and lateral wood.

• Korea-Australia Rheology Journal
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• v.12 no.2
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• pp.107-117
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• 2000

Prediction of the product shape in sheet casting process is performed from the numerical simulation. A three-dimensional finite element method is used to investigate the flow behavior and to examine the effects of processing conditions on the sheet produced. Effects of inertia, gravity, surface tension and non-Newtonian viscosity on the thickness profile of the sheet are considered since the edge bead and the flow patterns in the chill roll region have great influence on the quality of the products. In the numerical simulation with free surface flows, the spine method is adopted to update the free surface, and the force-free boundary condition is imposed along the take-up plane to avoid severe singularity problems existing at the take-up plane. From the numerical results of steady isothermal flows of a generalized Newtonian fluid, it is shown that the draw ratio plays a major role in predicting the shape of the final sheet produced and the surface tension has considerable effect on the bead thickness ratio and the bead width fraction, while shear-thinning and/or tension-thickening viscosity affect the degree of neck-in.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.199-208
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• 1986

The effects of $Mg^{++}$ upon the spontaneous contraction activated by 1 IU/l oxytocin were studied in the isolated rat uterine muscle. Longitudinal muscle strips u·ere prepared from the rat uteri at the estrous stage. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) In the uterine strips contracting spontaneously, as $Mg^{++}$ concentration increased in the Tyrode solution the amplitude of peak tension decreased in all the experimental solutions containing the various concentrations of $Ca^{++}\;(0.5{\sim}4 mM)$. And the amplitude of peak tension increased in inverse proportion to the $[Mg^{++}]/[Ca^{++}]\; ratio$. It is suggested that the tension-lowering effect of $Mg^{++}$ would be developed through decreasing intracellular ionized free calcium ion concentration by uncertain mechanism. 2) The frequency of the uterine contraction activated by oxytocin increased as the $[Mg^{++}]/[Ca^{++}]\;ratio$ ratio increased up to 1/2, but the frequency decreased above this ratio. It is speculated that $Mg^{++}$ would influence the excitability control action of $Ca^{++}$.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.740-745
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• 2001

There are two kinds of method to calculate the equivalent friction coefficients at V groove. One is to consider the firction in radial direction. The other is to neglect the friection in radial direction. The values calculated from the two methods is different of which ratio is in the range from two times to five times. So it is necessary to study which is correct in the view of force equilibrium and machine design.

• Journal of Korean Medicine Rehabilitation
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• v.29 no.2
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• pp.189-194
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• 2019

Objectives The purpose of this study was to examine comparison of tension according to the type of sling cord during the bridging exercise with sling in stroke patients. Methods Twenty six stroke patients were recruited for this study. Subjects were randomly performed sling bridging exercise with three types of sling cords such as nonelastic cord with affected side-nonelastic cord with non affected side (NC-NC), nonelastic cord with affected side-elastic cord with non affected side (NC-EC), and elastic cord with affected side-nonelastic cord with non affected side (EC-NC). They were measured tension with a tensiometer of sling cord during the bridging exercise with sling. Results The tension of sling cord was significantly different in affected side, non affected side, and tension ratio of affected side/non affected side. There were significant differences tension in NC-EC from NC-NC and EC-NC and the NC-EC method was increased tension of affected side and decreased tension of non affected side. Conclusions These results showed that the NC-EC method was improved the symmetry of affected side and non affected side. Sling exercise with appropriate type of sling cord should be increased activities of affected side and improved recovery in stroke patients.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.350-355
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• 1998

Preplaced aggregate concrete in the building fields has recently been used in the partial repair works for damaged reinforced concrete structures, and polymer-modified mortars have been employed as grouting mortars for the preplaced aggregate concrete. The objective of this study is to clear the properties of polymer-modified grouting mortars. Polymer-modified mortars using a polystyrene acrylic(St/Ac) emulsion as grouting mortars for preplaced aggregate concrete are prepared with various mix proportions, and tested for flexural and compressive strengths, adhesion in tension. The flexural strength of emulsion-modified grouting mortars does not give much variation with increasing fly ash replacement for cement and sand-binder ratio. With increasing polymer-binder ratio, the flexural strength and adhesion in tension of St/Ac emulsion-modified grouting mortars increases, become nearly constant or reaches a maximum at a polymer-binder ratio of 5%. From the test results, St/Ac emulsion-modified grouting mortar with a polymer-binder ratio of 5%, a fly ash replacement of 10% for cement and sand-binder ratio of 1.0 is recommended as a grouting mortar for preplaced aggregate concrete.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.65-73
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• 2001

Herein, a theoretical method based on the catenary model Is applied to obtain the tension and drag forces acting on the trash curtain which is deployed at river for the prevention of floating debris inflow into the ocean. Under the assumption that fluid drag is perpendicular to the trash curtain, the tension and drag forces are uniform along the trash curtain. As a numerical model, the trash curtain is moored both symmetrically and asymmetrically with respect to the flow. The tension and drag forces on the trash curtain are investigated according to the change of Bap ratio and inclined angle of the trash curtain. Numerical results show that tension parameter is increased as the gap ratio is increased. It is found that tension parameter is reduced as the inclined angle is increased in the case of asymmetric deployment. The numerical model is applied to the specific problem for the trash curtain (200m) deployed at the Tancheon on the Han river. The maximum inflow velocity that anchor system can endure is 2m/sec.