• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.616-619
• /
• 2000

The optimum design of a structure requires to determine economical member size and shape of a structure which satisfies the design conditions and functions. In this study, it is attempted to minimize a dead weight of the bogie frame. Therefore, shape optimization is performed for a bolster rib at first and then size optimization for the thickness of top and bottom plate. For the efficient reduction of a weight of a bogie frame, various ellipses centered at a centroid of a bolster rib are made and tried. For the shape optimization, a major axis and an eccentricity of an ellipse are chosen as design variables. From the numerical results of shape and size optimization of a bogie frame, it is known that the weight can be reduced up to 12.476 Y4717.21 kg) with displacement and stress constraints.

• KOREAN POULTRY JOURNAL
• /
• v.33 no.1 s.375
• /
• pp.147-151
• /
• 2001

우리나라 육계산업이 탄생된 이래 성장산업으로써 괄목한 만한 발전을 이룩하였으나, 평균 출하중량 1.5kg의 소형닭 생산구조로 형성되어 있기 때문에 계육 가공품 개발에 의한 새로운 소비창출이나 부분육 수출이 어려운 실정이고, 가공용 부분육의 수입이 증가하고 있는 실정이다. 육계를 크게 길러 출하하게 되면 생산비의 절감은 물론 다양한 가공품의 개발과 국내용과 수출용의 2원화 생산이 아닌 일원화도 가능하다. 대형육계를 생산하기 위해서는 다음과 같은 기술들이 상호 유기적으로 결합되어야만 가능할 것이다. 1. 출하말기까지 양호한 계사환경의 유지가 가능한 계사 및 환기장치 확보 2. 강건한 병아리의 확보와 초기 성장 억제 및 후기 보상성장 유도기술 적용에 의한 폐사율의 감소 3. 최종상품의 용도에 알맞은 사료 급여 및 암수분리 사육에 의한 2단출하 사육기술의 정착에 의한 대형육계 생산 4. 철저한 방역에 의한 질병차단 및 출하, 도계처리 과정의 오염방지

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.1
• /
• pp.121-128
• /
• 2004

This study aims to attain the basic data needed for the adaptation and application of polymer cement concrete as a new construction material by reviewing the various physical characteristics of polymer cement concrete following the changes in polymer type. The research found that cement concrete mixed with polymer, while it had some variation, had excellent qualities in all of compressive strength, tensile strength, water absorption, weight reducing ratio, and resistance of freezing and thawing.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.3
• /
• pp.381-389
• /
• 2015

In this study, the effects of moisture content and particles size of ground particles of torrefied larch chips on the pelletizing process were investigated depending on torrefaction conditions ($220^{\circ}C$-50 min, $250^{\circ}C$-50 min, $250^{\circ}C$-120 min). The moisture content in the torrefied chip decreased to 0.69~1.75%, while ash content and calorific value increased compared to untreated chip. In addition, weight loss significantly increased during torrefaction due to hemicellulose degradation. The carbon content in torrefied larch chip increased compare to untreated larch chip, while the hydrogen and oxygen contents decreased. The lignin and glucan contents in torrefied larch chip increased with increasing severity of the torrefaction condition, while hemicellulose decreased. In the particle size distribution of ground particles of torrefied larch chip, larch torrefied at severe conditions was found to produce smaller particles (~1 mm) than that of the larch torrefied at mild conditions. Macropore (over $500{\AA}$) in the torrefied particle was produced during torrefaction. During the pelletizing using ground particles of torrefied larch chip, the pressure needed in pelletizing decreased and pellet length increased with increasing moisture content, regardless of the particle size.

• Journal of Korea Soil Environment Society
• /
• v.4 no.1
• /
• pp.75-83
• /
• 1999

The purpose of this study is to investigate the chemical characteristics of the leachate for the open(illegal) dumping waste. In this study, the open dumping waste were mixed with 0, 5, 10, 15% of bentonite in each Iysimeter as a rate of weight. The simulation was evaluated by CODcr, ${NO_3}^-$, ${SO_4}^{2-}$, $Cl^-$ and heavy metals in leachate. As a result, the mixed waste with bentonite in all Iysimeters showed the reduction of CODcr and heavy metals were hardly detected. The removal rate of ${NO_3}^-$, ${SO_4}^{2-}$, $Cl^-$ was increased with the mixing rate of bentonite.

• Journal of the Korean Wood Science and Technology
• /
• v.43 no.3
• /
• pp.327-333
• /
• 2015

To measure the dimensional stability of three softwoods by vacuum pressurization of water soluble melamine-formaldehyde (MF) resin impregnation process, properties of resin treated compressed woods (compregs) were measured after impregnating the water soluble MF resin into three coniferous wood species for different impregnation times and resin concentrations. As the resin concentration was higher and impregnation time was longer, coefficients of volumetric shrinkage and anti-volumetric swelling efficiency increased, but coefficients of volumetric swelling, anti-volumetric swelling efficiency and absorption decreased. Also, weight percent gain increased remarkably as the resin concentration was high, but there was no uniform relationship with impregnation time.

• Clean Technology
• /
• v.12 no.4
• /
• pp.238-243
• /
• 2006

The aggregate properties of chilled converter slag reformed by atomizing liquid converter slag were investigated. The properties of mortars with various replacement of standard sand by chilled converter slag as recycled fine aggregates were investigated. The particle shape of chilled converter slag by atomizing was a sphere with an open cavity which is enclosed with two layers like a bored coconut. Specific gravity, unit weight and fineness modulus increased with increasing the replacement, and solid content had the maximum at the replacement of 75% and water absorption rate had the minimum at the replacement. The hardened mortars with higher replacements have the higher specific gravity and the denser texture.

• Journal of the Korean GEO-environmental Society
• /
• v.18 no.12
• /
• pp.5-11
• /
• 2017

The 19 mm-sized aggregate was produced by melting vinyl waste (waste polyethylene film) generated from vinyl greenhouses in rural areas. It was mixed with As'cone at various weight ratios, and then insulation effect test, tension test after repeated freezing and thawing, ice pull-out strength test and field density test were conducted for the mixtures. These results demonstrated that as the mixing ratio of polyethylene aggregate increased, the insulation effect increased, due to the many pore spaces that existed in the polyethylene aggregate. After repeatedly freezing and thawing As'cone, the tensile strength significantly increased at 2.5% of the polyethylene aggregate content rather than 0% of polyethylene aggregate content but it also slightly decreased at 5% and 10% of polyethylene aggregate content in comparison to 2.5% of its polyethylene aggregate content. As'cone added with polyethylene aggregate by 2.5% resulted in lower ice pull-out strength than that of normal As'cone. As a result of the porosity test for the samples taken at the site, porosity of the As'cone, which added polyethylene aggregate, was smaller than that of the general As'cone.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.1
• /
• pp.19-25
• /
• 2017

In this study, a electrostatic filter which could be applicable to road environment was developed and evaluated in adsorption capacity. The evaluation were performance for removal by particle size and adsorption amount by pressure using ASERAE 52.1 and 52.2. The range of size for removal test was $0.3{\mu}m{\sim}10.0{\mu}m$ which had 12 steps. The filter showed 91.3% removal efficiency from $2.5{\mu}m$ and under the size, average 53.5% proportional to decreasing size value. The weight removal was 96.7% from 22.6 mmaq, initial pressure to 35 mmaq, end pressure with $715.9g/m^2$, the adsorption amount. The shape of isotherm was expressed as Langmuir's one. After washing saturated filter with dust to end pressure, the initial pressure and adsorption amount of the filter showed a light drop with no removal efficiency decline.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.3
• /
• pp.285-291
• /
• 2015

Purpose: The hydrogel lenses have been functionalized with HA(Hyaluronic Acid) using two different methods: construction of an IPN(Interpenetrating Polymer Networks) and formation of CCB(Chemical Covalent Bonding). The lysozyme adsorption and physical properties such as optical transmittance and water content of the hydrogel lenses have been investigated in order to determine whether method is suitable for the application potentials in contact lens industry. Methods: HA have been added to the hydrogel lenses prepared in the Lab using the two different method, e.g. IPN and CCB. The optical transmittance was measured in the wavelength range of 300~800 nm. The water content was measured by the gravimetric method using 0.9% NaCl saline solution. The amounts of adsorbed lysozyme on the contact lenses was analyzed by HPLC after incubation for 12h in artificial tears. Results: The water content of the HA added hydrogel contact lenses was increased, and the lens made by IPN method showed higher water content than the lens made by CCB method. The optical transmittance was over 90% both before and after addition of HA. Comparing the lysozyme adsorption reduction ratio, contact lens manufactured by IPN method was 60.0%, and the lens made by CCB method was 40.4%. Conclusions: CCB method is appropriate to distribute the functional material evenly throughout the lens, whereas IPN method is effective for the case of giving the functionality on the lens surface without phase separation.