• Journal of IKEEE
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• v.21 no.4
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• pp.368-374
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• 2017

In this Paper, we developed a low power type LED security light using LED lighting that substitutes a 220[V] commercial power source for a solar cell module instead of a halogen or a sodium lamp. in addition, a PWM type drive control circuit is designed to minimize the heat generation problem and the drive current of the LED drive controller. in developed system, The light efficiency measurement value is 93.6[lm/W], and a high precision temperature sensor is used inside the controller to control the heat generation of the LED lamp. In order to eliminate the high heat generated from the LED lamp, it is designed to disperse quickly into the atmosphere through the metal insertion type heat sink. The heat control range of LED lighting was $50-55[^{\circ}C]$. The luminous flux and the lighting speed of the LED security lamp were 0.5[s], and the beam diffusion angle of the LED lamp was about $110[^{\circ}C]$ by the light distribution curve based on the height of 6[m].

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.318-326
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• 2014

This study was conducted to investigate the potential of non-used forest biomass residues as raw materials for making wood pellets with additives such as wood tar and starch and to evaluate fuel characteristics of the pellets. Wood tar, a by-product provided from the carbonization process of wood, could be a suitable additive for wood pellet production due to its higher calorific value and lower hazardous heavy metals, such as cadmium and mercury, compared to woody biomass. When the wood tar (10 wt%) was added, the calorific value was increased from 4,630 kcal/kg (wood pellet without additive) to 4,800 kcal/kg (wood pellet with additive). With the increase of additive amount into wood pellet, the length and individual density of wood pellet increased. In addition, bulk density of the pellets was increased, whereas the fine content was decreased. Consequently the overall productivity of wood pellets was improved by adding 2 w% additives into wood pellets; the percentage of productivity increase was 5.9% and 4.9% for adding starch and wood tar, respectively.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.339-345
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• 2014

For enhancing productivity of glulam, high frequency (HF) curing technique was researched in this study. Heat energy is generated by electromagnetic energy dissipation when HF wave is applied to a dielectric material. Because both lamina and adhesives have dielectric property, internal heat generation would be occurred when HF wave is applied to glulam. Most room temperature setting adhesives such as phenol-resorcinol-formaldehyde (PRF) resin, which is popularly used for manufacturing glulam, can be cured more quickly as temperature of adhesives increases. In this study, dielectric properties of larch wood and PRF adhesives were experimentally evaluated, and the mechanism of HF heating, which induced the fast curing of glue layer in glulam, was theoretically analyzed. Result of our experiments showed relative loss factor of PRF resin, which leads temperature increase, was higher than that of larch wood. Also, it showed density and specific heat of PRF, which are resistance factors of temperature increase, were higher than those of wood. It was expected that the heat generation in PRF resin by HF heating would occur greater than in larch wood, because the ratio of relative loss factor to density and specific heat of PRF resin was greater than that of larch wood. Through theoretical approach with the experimental results, the relative strengths of ISM band HF electric fields to achieve a target heating rate were estimated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.644-648
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• 2019

This study examined effects of the wall thermal conductivity coefficients on the thermal fluid phenomenon of a compartment fire. The reduced scale compartment was 0.4 m in width, 0.6 m in length and 0.6 m in height with a fire-board, which has a thermal conductivity coefficient of $0.18W/m{\cdot}K$. The local temperature at a 0.37 m height and the overall heat release rate were measured under the following experiment conditions: a $0.12m^2$ opening area and $0.01m^2$ pool size of a gasoline fire. The numerical results obtained by the Fire Dynamic Simulation were compared with the experimentally measured temperature. The deviations were within 10 % in the period of the steady state for maximum heat release rate (4.8 kW). The numerical results show that the average temperature of the compartment wall decreases by approximately 71 % with increasing thermal conductivity coefficient from $0.1W/m{\cdot}K$ to $100.0W/m{\cdot}K$ on the fixed heat release rate.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.32-32
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• 2017

2012년부터 도입된 "신재생에너지 의무할당제(RPS)"로 인하여 500MW이상의 설비 용량을 갖춘 발전소의 경우 총발전량에서 일정 비율을 신재생에너지로 공급하여야 한다. 이러한 신재생에너지 중 농업부산물은 목질계 바이오매스의 한 종류로 '탄소중립(Carbon Neutral)' 연료이며 기존 화석연료와 혼소로 활용 할 수 있는 장점을 지니고 있다. 그러나 낮은 발열량, 운송 및 저장비용, 일정하지 않은 연소특성의 문제로 인하여 대부분 노지에 방치되거나 버려지고 있다. 이러한 버려지는 농업부산물을 효율적으로 활용하기 위한 방법 중 하나로 반탄화(Torrefacation) 처리가 대두되고 있다. 반탄화 처리 시, 발열량이 증대되며, 저장과 이송에서의 이점을 갖게 된다. 그러나, 반탄화는 공정 과정중 질량손실에 따른 에너지 총량의 감소한다는 단점을 가지고 있다. 이에 본 연구에서는 효율적인 반탄화공정을 위한 질량감소모델을 제시 하고자한다. 승온 속도(heating rate)를 $7.5^{\circ}C/min$, $15^{\circ}C/min$, $22.5^{\circ}C/min$의 조건에서의 열중량분석 결과를 토대로 속도모델식(Arrhenius method, Ingraham & Marrier method 등)을 적용하여, 반응속도상수를 도출하였다. 이 반응속도상수를 이용하여 질량감소 모델을 정립하였고, 이를 실험결과와 비교, 검증하였다.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.208-213
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• 2013

In this study, the effect of phosphorus flame retardants on the flame retardancy of the flexible polyurethane foam (PUF) was investigated. Tetramethylene bis(orthophosphorylurea) [TBPU] and phosphinyl alkylphosphate ester [CR-530], resorcinol bis diphenylphosphate [RDP], triethyl phosphate [TEP] were used as flame retardants. The results of thermogravimetric analysis (TGA) indicate that TBPU added PUF produces more charred residues than the other flame retardant added PUF. It was found that TBPU added PUF exhibits low mean heat release rate (HRR), peak HRR, effective heat of combusion (EHC), mass loss rate (MLR), CO yield and $CO_2$ compared to those other flame retardants.

• Fire Science and Engineering
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• v.13 no.4
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• pp.7-12
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• 1999

Thermal properties of EVA dust and its risks of coexisting with oxidizer were investigated by a pressure vessel. The decomposition of EVA dust with temperature using DSC and the weight loss with temperature using TGA were also investigated to find the thermal hazard of EVA dust. Using the pressure vessel which can estimate ignition and explosion of EVA dust coexisting with oxidizer by bursting of a rupture disc, many experiments have been conducted by varying the orifice diameter, heating rate, the weight ratio of the sample coexisting with oxidizer, and the species of oxidizer. According to the results of the thermal analysis of EVA dust, a little change of the decomposition initiation temperature with the heating rate could be found and the decomposition temperature zone of EVA dust was 250 to 50$0^{\circ}C$. The risk of EVA dust coexisting with oxidizer was increased as the orifice diameter was decreased. On the other hand, it was increased as the heating rate and the weight ratio of the sample coexisting with oxidizer were increased. In addition, the risk of EVA dust coexisting with oxidizer was affected by the decomposition temperature of the sample and oxidizer, respectively, at slow heating rate, but it was affected by the oxygen weight percent of oxidizer at fast heating rate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.223-229
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• 2017

When concrete is exposed to neutron rays for a long time, the concrete tends to become activated. If activated, it is classified as middle or low level radioactive waste. However, the great amount of the activated concrete is hard to dispose. In this study, low-activation cement was developed for decreasing the activated waste from shielding concrete around nuclear reactor. Furthermore, the manufactured low-activation was analyzed with activation nuclide Eu, Co. The low-activation cement showed great advantage for low-activation with detecting none of Eu and 3.75ppm of Co while ordinary portland cement showed 0.4~0.9ppm of Eu, 5.5~19.8ppm of Co content. As the results of physical properties of the low-activation cement, it is similar to type 1 ordinary portland cement and accords with type 4 low heat portland cement. Meanwhile, as for the chemical properties of the cement, it accords wite type 1 and 4 at the same time.

• Resources Recycling
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• v.15 no.1 s.69
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• pp.12-19
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• 2006

Rice straw is one or the main renewable energy sources in Korea. Bio-oil is produced from rice straw with a lab-scale equipment mainly with a fluidized bed and a char removal system. It was investigated how the reaction temperature affected the production of bio-oil and the efficiency of a char removal system. To elucidate how the temperature depended on the production of bio-oil, experiments were conducted at $466^{\circ}C,\;504^{\circ}C\;and\;579^{\circ}C$, respectively. The mass balance was established in each experiment, and the produced gas and oil were analyzed with the aid of GCs and a GC-MS system. The char removal system is composed of a cyclone and a hot filter. Tn the experiments, we observed that the production of bio-oil was decreased with temperature, and the bio-oil contained very useful chemicals.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.1
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• pp.76-84
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• 2013

In this study, thermal weight loss, non-isothermally experiment, chemical composition analysis, calorific value, activation energy (E) were investigated to analysis the kinetic study of RDF, wood pellets, waste wood, waste textile and waste vinyl. When the chemical composition of solidification fuel was compared, the moisture content of RDF was less than the wood pellet and when the kinetic study was compared, the combustion reaction rate of the waste vinyl was higher than any other solidification fuels. However when the combustion efficiency was compared by the activation energy, the RDF had the higher efficiency than other wastes. RDF can be found that the reaction takes place between $320{\sim}720^{\circ}C$ depending on the heating rate.