• Journal of the Korean Applied Science and Technology
• /
• v.33 no.2
• /
• pp.264-270
• /
• 2016

This Study is to into fuel using a torrefation reaction to food waste. When the fuel of only food waste alone, fuel value is was performed at a ratio of sewage sludge constant attempts to prevent low. Mixing ratios of food waste and sewage sludge, 10:0, 8:2, 6:4, 5:5. Regardless mixing ratio, it was possible to confirm that decreases the moisture content of 10% or less at a reaction temperature of $240^{\circ}C$ or higher. As the ratio of the reaction temperature and the sewage sludge is high, the fixed carbon content is increased. It was measured at up to 36%(mixing ratios6:4, reaction temperature $270^{\circ}C$) from the initial 1.1%. From the reaction temperature $240^{\circ}C$ satisfied with 3000Kcal/Kg or more is a SRF criteria shows the calorific value. It was possible to obtain a heating value that is increased from the raw sample approximately sextuple. As reaction temperature is heightened, Van krevelen Diagram moved to the range of Lignite range. It was possible to obtain high fuel ratio and 5,500Kcal/kg or less of a combustility index as the sewage sludge mixing ratio becomes high. Increase the fixed carbon content, than those food waste alone solid fuel into and improved fuel costs, it is necessary to ensure that the quality of the fuel is improved.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.5
• /
• pp.776-784
• /
• 2016

In this study, green Larix kaempferi lumber was heat-treated by using superheated steam (SHS) at a pilot scale and then various physico-mechanical properties of the heat-treated wood were evaluated and compared with the properties of conventional hot air (HA) heat-treated wood. Decay resistance of brown rot fungi and compressive strength parallel to the grain of the SHS heat-treated wood without occurrence of drying check from green lumber were increased. On the other hand, density, equilibrium moisture content, shrinkage, and bending strength of the SHS heat-treated wood were lower than those of the conventional HA heat-treated wood. Because heat transfer and thermal hydrolysis of SHS heat treatment was accelerated by a large amount of water, the effect of SHS heat treatment on the physico-mechanical properties was higher than that of HA heat treatment at the similar conditions of temperature and time. From the results of this study, because green lumber can be heat-treated without occurrence of cracks or checks by using SHS and similar heat treatment effect on the physico-mechanical properties of wood can be produced despite a low temperature or short time of heat treatment, it is expected that heat time and energy consumption could be reduced by using SHS.

• Korean Journal of Food Science and Technology
• /
• v.14 no.3
• /
• pp.257-264
• /
• 1982

In the present stud changes of some chemical and physical properties of a soybean oil, aerated at 120 ml/min through a porous gas distributor and oxidized at $45^{\circ}C{\sim}180^{\circ}C$, was investigated. The results of the study were as follows: The peroxide, thiobarbituric acid, and iodine value of the soybean oil which was aerated at 120 ml/min increased rapidly as oxidation temperature exceeded over $80^{\circ}C$. The acid value of the oil increased very rapidly as the oxidation temperature passed over $160^{\circ}C$. The content of the unsaturated fatty acid of the oil decreased considerably as the oxidation temperature exceeded over $80^{\circ}C$, whereas that of the saturated fatty acid did not change appreciably. This related well to the changes of the iodine value of the oil subjected to the same experimental conditions. The viscosity and refractive index of the oil increased rapidly as the oxidation temperature passed over $180^{\circ}C$. The following linear relationship hold for the viscosity and refractive index of the oil in the present study. $$V=Aexp({\frac{E}{RT}})$$ where V=viscosity(poise), A=constant, E=activation energy for viscous flow, R=gas constant, T=oxidation temperature$(^{\circ}K)$. The following relationship also hold for the viscosity and refractive index$({n^{20}}_D)$ of the oil at the present experimental conditions. $${n^{20}}_D=1.4614+7.333{\times}10^{-5}t+2.9612{\times}10^{-3}\;InV$$ where t=temperature$(^{\circ}C)$ at which the viscosity was measured.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 1991.04a
• /
• pp.71-74
• /
• 1991

구조물의 진동특성을 파악하기 위한 실험적 모우드 해석법에서 기진력을 제 공하는 한 방법으로 힘 측정기가 부착된 해머를 이용한 충격시험기법이 널 리 사용되고 있다. 충격해머 시험의 유용성은 기진력의 에너지가 정현파 기 진력의 경우처럼 특정 주파수대에 산재해 있는 것이 아니라 가용 주파수 영 역내에 연속적으로 분포해 있다는 점이며 이러한 충격력은 가용 주파수 범 위내에 있는 모든 고유진동형을 여가시킬 수 있다는 장점이 있다. 충격헤머 가 가지고 있는 동적특성은 구조물을 가진시키는 선형충격량의 크기를 결정 하며, 이는 다시 충격력의 크기와 가용 주파수 범위를 결정하게 된다. 일반 적으로 가진주파수 범위는 해머의 질량에 반비례하고 충격해드의 경도에 비 례하는 것으로 알려져 있다. 해머의 질량 자체가 충격력의 크기를 좌우하기 도 하므로, 가진력의 크기를 고려하여 해머의 질량이 선택되며 충격헤드는 충격시간을 조절하기 위하여 적절히 선택된다. 충격해머에 장착된 힘측정기 의 감도는 해머질량과 충격헤드의 질량 변화에 영향을 받게 되는데, 충격 시 험시 측정되는 값은 해머에 부착되어 있는 힘측정기에 가해지는 힘인 반면 구조물에 가해지는 기진력은 충격해드와 구조물사이에 발생되는 힘이다. 이 두 힘의 비는 해머 및 충격해드의 질량효과에 따라 좌우된다. 주어진 충격시 험에서 충격해머의 질량효과를 정확히 조건에 따라 감도보정을 해 주어야 한다. 충격해머의 감도보정에 대해서는 문헌[2]에 잘 나타나 있다. 본 논문에 서는 전압감도에 미치는 영향을 파악하고자 질량 효과를 고려한 수학적 모 형을 제시하고 그 모형의 타당성을 실험을 통해 검정하고자 한다.방법 을 제시하였다. 이와 아울러 제어계의 환경변화에 따른 파라메타의 변화에 적응적으로 응답이 가능해야 하는 적응 소음제어 시스템에서, 음향궤환과 함 께 필히 고려해야 하는 부가적인 전달함수의 영향을 고려한 능동 소음제어 에 대해 연구하였다. 경량화 추세에 따라 지반이나 케이싱이 경량이거나 유연하여 회전축과 동적으로 연성된 경우 회전축-베어링-지반으로 이루어진 2중구조의 회전축 계 동특성을 해석할 수 있는 프로그램을 개발하므로서 회전 기계류의 진동 전반에 걸친 문제점에 대한 그 원인과 현상을 명확히 분석하여 국내의 전기 계류의 보다 신뢰성있는 설계 및 제작자료를 확보하는데 기여할 수 있게 하 였다.존의 small molecular Gd-chelate에 비해 매우 큼을 알 수 있었다. MnPC는 간세포에 흡수된 후 담도계로 배출되는 간특이성 조영제임을 확인하였다. 장비 내에서 반복 시행한 평균값의 차이는 대체적으로 유의한 차이가 없었으나, 다른 장비에서 반복 시행한 장비간의 사이에는 유의한 차이가 있는 경우가 더 많았다. 따라서 , MRS 검사를 소뇌나 뇌교의 어떤 절환에 적용하기 전에 각 장비 마다 정상 기준치를 반드시 얻은 후에 이상여부를 판 정하는 것이 필수적이라고 생각된다.EX> 이상이 적절한 진단기준으로 생각되었다. $0.4{\;}\textrm{cm}^3$ 이상의 좌우 부피차를 보이는 모든 증례에서 육안적으로도 해마위축이 뚜렷이 나타났다. 결론 : MR영상을 이용한 해마의 부피측정은 해마경화증 환자의 진단에 있어 육안적인 MR 진단이 어려운 제한된 경우에만 실제적 도움을 줄 수 있는 보조적인 방법으로 생각된다

• International Journal of Highway Engineering
• /
• v.13 no.2
• /
• pp.103-114
• /
• 2011

Usage of bicycle has been supported the universal reduction of energy consumption and $CO_2$. For the same purpose, new constructions for long length bike roads are planned in Korea. Recently, laboratory tests of physical properties and resistance against environmental loading about optimum mix design of roller compacted concrete, that have advantages of high structural performance by cement hydration and aggregate interlocking, simple construction procedure and low construction cost, are performed for the effective construction of new bike roads. However, properties of roller compacted concrete had different results between laboratory and field tests since it had different compaction method. Also, construction method of roller compacted concrete are not defined for the application of bike roads since it had different demand performance such as thin pavement thickness, low strength and etc with road pavements. Thus, in this experimental research was launched to evaluate the core properties, visual inspection, compaction ratio, water content, thickness reduction rate of roller compaction, skid resistance and roughness by experimental construction about variable mix proportion and compaction method based on laboratory test results. And construction method of roller compacted concrete pavement were suggested for the application of bike roads.

• Magazine of the Korea Concrete Institute
• /
• v.6 no.2
• /
• pp.97-107
• /
• 1994

The objective of this study is to develop polymer-impregnated concrete(PIC), which is a newly developed composite material made by impregnating polymer impregnanls into hardened normal concrete, and to develop analytical techniques for its proper applications. Crystalline methyl methacrylate(MMA) is chosen as a monomer of polymer impregnants. The corrlpositions of polymer impregnants and producing processes are developed by analyzing the effects of penetration, polymerization, thermal safety, and strengthening characteristics. On t he basis of experimental results of this study, various strength characteristics and stress strain constitutive relations are formulated in terms of the compressive strength of normal concrete and the polymer loadings, which can be applied for analysis and design of PIC members. In order to provide a model for fracture analysis of flexural members, fracture toughness, fracture energy, critical crack width, and tension softening relations near crack tip are also formulated in terms of member depth, initial notch depth, and the flexural strength of normal concrete. The structural analysis procedure and the finite element computer program developed in the study are applicable to evaluate elastic behavior, ultimate strength, and tension softening behavior of MMA type PIC structural members subject to various loading conditions. The accuracy and effectiveness of the developed computer program is examined by comparing the anal ytical results with the experimental results. Therefore, it is concluded that the developed structural analysis procedure and the finite element computer program are applicable to analysis and design of in-situ and precast PIC structural members.

• Magazine of the Korea Concrete Institute
• /
• v.6 no.1
• /
• pp.120-130
• /
• 1994

The purpose of this study is to propose the analytical model for the hysteretic behavior of Reinforced Concrete bearn-column joints under various loading history. Discrete line elernents , YVith inelastic rotational spring was adopted to consider the movement of plastic hinging zone influenced by the details of longitudinal reinforcements. Also hysteretic model was constructed by excluding such variables which can not be utilized in dynamic analysis of Reinforced Concrete. structure that it will be adoptable in two-dimensional inelastic frame ardysis with 6-DOF. From the analysis of previous test results, it was found that stiffness deterioration caused by inelastic hysteretic loadings can be predicted by the functron of basic pinching coefficients, ductility ratio.and yield strength ratio of members. Strength degradation coefficients were newly proposed to explain the difference of inelastic behavior of members caused by spacing ratio of transverse steel and sectlon aspect ratio. The energy dissipation capacities calculated using the analytical model proposed in thls paper show a good agreements w~lh test results by an error of 10~20%.

• Journal of the Korean earth science society
• /
• v.34 no.6
• /
• pp.492-506
• /
• 2013

The historical accounts and materials about the eruption of Mt. Baekdusan as observed by the geological survey is now showing some signs of waking from a long slumber. As a response of the volcanic eruption of Mt. Baekdusan, water release may occur from the stored water in Lake Cheonjii caldera. The volcanic flood is crucial in that it has huge potential energy that can destruct all kinds of man-made structures and that its velocity can reach up to 100 km $hr^{-1}$ to cover hundreds of kilometers of downstream of Lake Cheonji. The ultimate goal of the study is to estimate the level of damage caused by the volcanic flood of Lake Cheon-Ji caldera. As a preliminary study a scenario-based numerical analysis is performed to build hydrographs as a function of time. The analysis is performed for each scenario (breach, magma uplift, combination of uplift and breach, formation of precipitation etc.) and the parameters to require a model structure is chosen on the basis of the historic records of other volcanos. This study only considers the amount of water at the rim site as a function of time for the estimation whereas the downstream routing process is not considered in this study.

• Journal of the Korean Institute of Gas
• /
• v.18 no.1
• /
• pp.46-51
• /
• 2014

The purpose of this paper is to study of the vehicle lamp manufacturing system composing ultrasonic waves connection process. Making lamp assembly plant, it was produced in the separate process as the injection molding, ultrasonic waves bonding, annealing in the constant temperature, lamp assembling and packing. But the improvement method producing the lamp was added with one-step process by one automation technique. As a result, welding with ultrasonic waves process, the method decreased the energy consumption and noise during ultrasonic waves welding. Therefore, this method used the mathematics modeling for checking validity, it selected the stability and suitable controller using transfer function of plant and bode chart. In this study, the $180^{\circ}$ revolution control system to turn injection part upside down was $M_{eq}\;lcos{\theta}(t)$ because of gravity influence. It effected to unstable condition a system. For solving this problem, it aimed the linearization and stabilization of system by elimination $M_{eq}\;lcos{\theta}(t)$ as applying Free-forward control technique.

• Journal of KIISE:Software and Applications
• /
• v.36 no.11
• /
• pp.936-946
• /
• 2009

A graph cuts method has recently attracted a lot of attentions for image segmentation, as it can globally minimize energy functions composed of data term that reflects how each pixel fits into prior information for each class and smoothness term that penalizes discontinuities between neighboring pixels. In previous approaches to graph cuts-based automatic image segmentation, GMM(Gaussian mixture models) is generally used, and means and covariance matrixes calculated by EM algorithm were used as prior information for each cluster. However, it is practicable only for clusters with a hyper-spherical or hyper-ellipsoidal shape, as the cluster was represented based on the covariance matrix centered on the mean. For arbitrary-shaped clusters, this paper proposes graph cuts-based image segmentation using mean shift analysis. As a prior information to estimate the data term, we use the set of mean trajectories toward each mode from initial means randomly selected in $L^*u^*{\upsilon}^*$ color space. Since the mean shift procedure requires many computational times, we transform features in continuous feature space into 3D discrete grid, and use 3D kernel based on the first moment in the grid, which are needed to move the means to modes. In the experiments, we investigate the problems of mean shift-based and normalized cuts-based image segmentation methods that are recently popular methods, and the proposed method showed better performance than previous two methods and graph cuts-based automatic image segmentation using GMM on Berkeley segmentation dataset.