• Textile Coloration and Finishing
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• v.31 no.4
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• pp.288-297
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• 2019

The specimens were heat treated at 180℃, 190℃, 200℃, 210℃ and 220℃ to observe the change of the physical properties of the double raschel pile fabric. The density, tensile strength, weight, elongation, dyeing characteristics, fabric surface morphology and cross sectional shape were observed by heat treatment temperature. Compared with untreated samples, weight, density and tensile strength were increased with increasing heat treatment temperature. No increase was observed at 220℃. In the case of elongation, it increased to 190℃ but thereafter it could not be observed. In the case of uprightness of brushed hair, it was observed that the gap between the yarns was narrowed and the density was increased and the straightness of the yarn and pile yarn was improved by widening the heat treatment temperature. As a result, it was observed that the uprightness was remarkably improved and the bulky properties was increased. It was also observed that the increase of the dyeability was observed with increasing the heat treatment temperature.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.633-640
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• 2005

Most existing methods for the footing settlement estimation are for either isolated or strip footings. No sufficient details are available for settlement calculation of footings with different shapes and multiple footing conditions, which are commonly adopted in actual construction projects. In this paper, estimation of footing settlements for various footing conditions of different shapes and multiple conditions is investigated based on Schmertmann's method with focus on values of the strain influence factor $I_z$. In order to examine the effect of multiple footing conditions, field plate load tests are performed in sands using single and double plates. 3D non-linear finite element analyses are also performed for various footing conditions with different footing shape and distance ratios. Results obtained in this study indicate that there are two significant components in the strain influence diagram that need to be taken into account for settlement estimation of rectangular and multiple footings: depth of $I_{zp}$ and depth of strain influence zone. Based on results from experimental and 3D non-linear finite element analyses, improved strain influence diagrams available for various footing conditions are proposed.

• Journal of IKEEE
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• v.22 no.2
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• pp.460-475
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• 2018

In the variable-speed wind energy system, to achieve maximum power point tracking (MPPT), the wind turbine should run close to its optimal angular speed according to the wind speed. Non-linear control methods that consider the dynamic behavior of wind speed are generally used to provide maximum power and improved efficiency. In this perspective, the mechanical power is estimated using Kalman filter. And then, from the estimated mechanical power, the wind speed is estimated with Newton-Raphson method to achieve maximum power without anemometer. However, the blade shape and air density get changed with time and the generator efficiency is also degraded. This results in incorrect estimation of wind speed and MPPT. It causes not only the power loss but also incorrect wind resource assessment of site. In this paper, the adaptive maximum power point tracking control algorithm for wind turbine system based on the estimation of wind speed is proposed. The proposed method applies correction factor to wind turbine system to have accurate wind speed estimation for exact MPPT. The proposed method is validated with numerical simulations and the results show an improved performance.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1617-1621
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• 2002

Two hundred and sixteen single comb white egg layers of the White Leghorn hens of 24 weeks of age were randomly allocated to 12 groups with three replications of six hens in each. Hens were fed in a factorial arrangement 2${\times}3{\times}$2, on diets containing either 16 or 18% crude protein with 0, 3 or 6% fish meal, replacing groundnut meal with soybean meal. Soybean meal incorporation improved (p<0.05) egg production, feed intake, feed conversion efficiency and egg weights. Egg quality traits of specific gravity, shape index, albumen index, yolk index and shell thickness remained unchanged. Laying performance was significantly (p<0.05) better at 18% than on 16% dietary protein level. Use of fish meal linearly improved egg production and feed conversion efficiency on diets supplemented with groundnut meal and fish meal incorporation showed quadratic improvement on feed conversion efficiency with SBM diets at 16% dietary protein level. Therefore, use of soybean meal as substitute of groundnut meal is recommended in layer diets, at 16% dietary protein level and fish meal incorporation could be beneficial for layers.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.1
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• pp.42-51
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• 1993

Recently, WC-Co have some excellent properities as the material for the mechanical component such as metallic moulding parts, ball dies parts, and punch parts. This paper describes the surface roughness and grinding force caused by experimental study on the surface grinding of WC-Co with ultra-precision like a mirror shape using diamond wheel. Also, some investigations are carried out using WA grinding wheel to increase improved ground surface roughness such as polishing, lapping effect. Some important results obtained here are summarized as follow. 1) Within this experimental grinding condition, we can be obtained $R_{max}.\;2\mu\textrm{m}\;R_a\;0.3\mu\textrm{m}$ whichare the most favourable ground surface roughness using #140 diamond wheel, and improved surface roughness values about 20 .approx. 25% throughout 5 times sparkout grinding 2) The value of surface roughness is Rmax. $0.49\mu\textrm{m},\;R_a\;0.06\mu\textrm{m}$ using #600 diamond wheel. 3) The area of no rack zone is less than $F_{n}$ 0.27N/mm, Ft 0.009N/mm

• Transactions of Materials Processing
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• v.24 no.6
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• pp.437-442
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• 2015

The development of polishing technology has enabled the production of injection molds with high quality surfaces and shapes. For products such as mobile phones which require high quality performance the use of plastic materials has many constraints such as shrinkage and deflection. The purpose of the current research is to use reverse engineering in order to find and analyze the data of a selected aspherical lens and then creating a process to design an improved lens. Additionally, the improved lenses are subject to molding analysis. In order to solve this problem, the lens construction program, Zemax, was used to analyze and optimize performance. In the case of optimization, the object was to eliminate spherical aberration and to find good MTF data. The result of the optimization data was similar to the MTF data found from a random lens. Specific resin and analysis conditions were selected and CAD modeling was done to enhance the injection molding analysis.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.499-509
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• 2014

Wood filler is a porous and anisotropic material having different size, shape, and aspect ratio. The use of wood fillers such as wood particle, wood flour, and wood pulp in wood plastic composites (WPCs) are growing rapidly because these wood fillers give improved strength and stiffness to WPCs. However, the wood fillers have originally poor compatibility with plastic matrix affecting the mechanical properties of WPCs. Therefore, to improve compatibility between wood and plastic, numbers of physical and chemical treatments were investigated. While the various treatments led to improved performances in WPC industries using petroleum-based plastics, full biodegradation is still issues due to increased environmental concerns. Hence, bio-based plastics such as polylactide and polyhydroxybutyrate having biodegradable characteristics are being applied to WPCs, but relatively expensive prices of existing bio-based plastics prevent further uses. As conventional processing methods, extrusion, injection, and compression moldings have been used in WPC industries, but to apply WPCs to engineered or structural places, new processing methods should be developed. As one system, co-extrusion technique was introduced to WPCs and the co-extruded WPCs having core-shell structures make the extended applications of WPCs possible.

• Journal of Korean Academy of Nursing
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• v.37 no.7
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• pp.1108-1118
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• 2007

Purpose: The purpose of this study was to identify the effects of hand acupuncture therapy on sleep quality by means of a sleep questionnaire, polysomnography and a cerebral blood flow test in $30{\sim}59$ year old adults. Methods: The study was a sham controlled design. Twenty-two adults were assigned to the pellet stimulating group (11) or sham group (11). The pellet stimulating group received hand acupuncture therapy using New Seoam Press Pellets number 1 for 4 weeks. On the other hand, the sham group used the same Adhesive tape in terms of shape, size and quality as New Seoam Press Pellets number 1 for 4 weeks. A Transcranial Doppler Ultrasonography and Carotid Duplex Ultrasonography examination were used for evaluating cerebral blood flow. Data was analyzed using the SPSS 12.0 version program with $X^2-test$, Fisher's exact test and Mann Whitney U-test. Results: In the pellet stimulating group, subjective sleep quality significantly improved more than that of the sham group. Among the sleep indices of the polysomnography, total sleep time and sleep latency of the sham group significantly improved. The cerebral blood flow test didn't show any differences. Conclusion: These results suggest that hand acupuncture therapy is effective for subjective sleep improvement only, not polysomnographical sleep indices and cerebral blood flow.

• Fashion & Textile Research Journal
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• v.7 no.1
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• pp.91-95
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• 2005

The purpose of this study is to investigate the improvement of fiber surface, physical properties and research the physical properties and dyeability of cotton fabrics treated with KOH solution at low and high temperature. The treatment conditions for mercerization with KOH were changed various temperatures(25, $90^{\circ}C$), concentrations(15, 20, 25, 30%. w/v) and times(30, 60, 180, 300sec). The effects of mercerization after KOH treatment estimated with tensile strength, tearing strength, shrinkage, drape stiffness, moisture regain, fiber surface, and dyeability. The optimal conditions were concentration of KOH 20%, time 180sec in low temperature and concentration of KOH 20%, time 60sec in high temperature. The results are as follows; Tensile strength, tearing strength and moisture regain were much improved than those of untreated cotton fabric. Shrinkage and drape stiffness of KOH treated cotton were more increased at $25^{\circ}C$ than $90^{\circ}C$. Fiber surface showed more rounded shape at $25^{\circ}C$ than $90^{\circ}C$. Dyeability of cotton fabrics improved by KOH treatment.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.163-170
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• 2015

Recently LED fish-attracting lamps have been more widely used in fisheries as low-cost and high-efficiency fishing gear, and development of long-life high-efficiency lamps is required through the design of LED packages to optimize heat resistance. This study developed an improved LED fish-attracting lamp with excellent heat performance, which was verified using a numerical model. Heat-resistance design factors such as the heat-radiation fin shape, PCB type, and LED chip count were investigated and optimized. Comparison with a commercial 180-W LED fishing lamp showed that the increase in initial temperature was 40% higher than that of the surrounding LED chip because of design errors in contact thermal resistance. The 250-W LED lamp developed in this study has a characteristic with thermal rising in linearly stable according to the heat source. In addition, luminance efficiency was improved by 20-65% by using flow-visualization simulation. A decrease of 45% in total power consumption with a fuel-cost reduction of over 55% can be expected when using these optimized heat release design factors.