There is ongoing research to develop lithium ion batteries as sustainable energy sources. Because of safety problems, solid state batteries, where electrolytes are replaced with solids, are attracting attention. Sulfide electrolytes, with a high ion conductivity of 103 S/cm or more, have the highest potential performance, but the price of the main materials is high. This study investigated lithium hydride materials, which offer economic advantages and low density. To analyze the change in ion conductivity in polymer electrolyte composites, PVDF, a representative polymer substance was used at a certain mass ratio. XRD, SEM, and BET were performed for metallurgical analyses of the materials, and ion conductivity was calculated through the EIS method. In addition, thermal conductivity was measured to analyze thermal stability, which is a major parameter of lithium ion batteries. As a result, the ion conductivity of LiH was found to be 106 S/cm, and the ion conductivity further decreased as the PVDF ratio increased when the composite was formed.

The precipitation effect of Al-6%Si-0.4%Mg-0.9%Cu-(Ti) alloy (in wt.%) after various heat treatments was studied using a laser flash device (LFA) and differential scanning calorimetry (DSC). Solid solution treatment was performed at 535 oC for 6 h, followed by water cooling, and samples were artificially aged in air at 180 oC and 220 oC for 5 h. The titanium-free alloy Al-6%Si-0.4%Mg-0.9%Cu showed higher thermal diffusivity than did the Al-6%Si-0.4%Mg-0.9%Cu-0.2%Ti alloy over the entire temperature range. In the temperature ranges below 200 oC and above 300 oC, the value of thermal diffusivity decreased with increasing temperature. As the sample temperature increased between 200 oC and 400 oC, phase precipitation occurred. From the results of DSC analysis, the temperature dependence of the change in thermal diffusivity in the temperature range between 200 oC and 400 oC was strongly influenced by the precipitation of θ'-Al2Cu, β'-Mg2Si, and Si phases. The most important factor in the temperature dependence of thermal diffusivity was Si precipitation.

The effect of precipitation and dissolution of Si on the thermal diffusivity in the Al-Si alloy system is reported in this study and solution heat treatment followed by aging treatment is carried out to determine the effects of heat treatment on the thermal characteristics. The solution treatment is performed at 535 oC for 4 and 10 h and then the specimens are cooled by rapid quenching. The samples are aged at 300 oC for 4 h to precipitate Si solute. The addition of 9 wt% silicon contents makes the thermal diffusivity decrease from 78 to 74 mm/s2 in the cases of solid solution treated and quenched samples. After quenching and aging, the Si solute precipitates on the Al matrix and increases the thermal diffusivity compared with that after the quenched state. In particular, the increase of the thermal diffusivity is equal to 10 mm/s2 without relation to the Si contents in the Al-Si alloy, which seems to corresponded to solute amount of Si 1 wt% in the Al matrix.

세계적으로 급증하는 전력수요에대처하고, CO2 배출을 줄이고자 인구가 밀집되어 있는 도 심지에 복합화력 발전소가 건설되고 있다. 환경규제가 계속적으로 강화됨에 따라 NOx 배출량을 줄이고 자 저 NOx 버너, SCR 등 여러 가지 설비들을 설치하고 있다. 본 연구는 경기도 고양시 소재의 일산열병합발전소 1개소에서 배출되는 질소산화물을 TMS를 이용하 여 배출계수를 산정하여 이를 전산유체동역학(CFD)에 적용하여 질소산화물의 거동을 살펴보고, 현장 실 측 결과와 비교 검토하였다. 실측 기간 중 측정 시간에 따른 주 풍향․풍속의 순간적인 변화로 인해 실측 결과와 CFD 모델링 결과 의 차이가 나타날 수 있으나, 모델링 결과와 실측 결과는 대부분 예측지점에서 유사한 농도로 나타났다. 향후 주변농도를 고려한 기여농도를 산출하여 실측농도에 가까운 예측농도 도출이 가능 할 것으로 판단 된다.

Experimental measurements of flame shape and heat transfer characteristics were performed for impinged inverse diffusion flame(IDF) using propane as a fuel. The purpose of this study is to identify the favorable co-axial inverse diffusion flame structure for impingement heating. The flame consisted of an entrainment zone and mixing and combustion zone. The heat flux which represents heat transfer rate is measured by using a heat flux sensor that is located at the center of the impingement plate. The inverse diffusion flame structure has been classified into six modes. In these modes, several favorable flames for impingement heating were identified. In this study, the parameters are overall equivalent ratio(Φ), nozzle to impingement plate distance(h/d), vertical distance from the stagnation point and Reynolds number(Re) of combustion air.

In order to analyze the densification behaviour of stainless steel powder compacts during hot isostatic pressing (HIP) at elevated temperatures, a power-law creep constitutive model based on the plastic deformation theory for porous materials was applied to the densification. Various densification mechanisms including interparticle boundary diffusion, grain boundary diffusion and lattice diffusion mechanisms were incorporated in the constitutive model, as well. The power-law creep model in conjunction with various diffusion models was applied to the HIP process of 316L stainless steel powder compacts under 50 and 100 MPa at . The results of the calculations were verified using literature data. It could be found that the contribution of the diffusional mechanisms is not significant under the current process conditions.

This study sought to determine the changes in weather conditions in urban streets, along with conditions of traffic and roads in urban areas. The variations in weather conditions depending on traffic differed according to distance. First, the temperature difference measured by traffic results is as follows: T1 point 1.03℃ , T2 point 1.04℃ , T3 point 0.9℃ , T4 point 1.01℃ , and T5 point 0.31℃ . The average difference between the measured temperatures by the point of measurement was 0.86℃ . The changes in wind velocity according to traffic volume results of the measurements is T1 point 1.32 m/s, T2 point 0.80 m/s, T3 point 0.29 m/s, T4 point 0.04 m/s, and T5 point 0.09 m/s. The difference between the average wind speeds was 0.51 m/s and traffic jams caused substantial differences in distance. The relative humidity tended to be inversely proportional to temperature. The measurements results ares T1 point 2.29%, T2 point 2.67%, T3 point 2.47%, T4 point 2.16%, and T5 point 0.91% The difference between the average relative humidity was 7.3%. In case of independent sampling T test according to traffic volume, changes in wind velocity and temperature were directly proportional to the level of statistical significance(p<0.01). On the other hand, relative humidity tended to be inversely proportional; however, there was no statistical significance.

In this study, we study the characteristics of thermal diffusion of cement paste at elevated temperature. Results of the experiments can be used to predict the fire damaged temperatures of concrete, and to recommend proper methods for repair and rehabilitation.

In this study, In this study, Simulation using COMSOL Multiphysics thermal flow program of A company was carried out for thermal diffusion analysis according to depth of concrete exposed to high temperature. As a result of the analysis, it was found that the thermal diffusivity decreased with the depth and the temperature difference decreased with the heating time.

In this study, In this study, Simulation using COMSOL Multiphysics thermal flow program of A company was carried out for thermal diffusion analysis according to depth of concrete exposed to high temperature. As a result of the analysis, it was found that the thermal diffusivity decreased with the depth and the temperature difference decreased with the heating time.

In this study, we study the characteristics of thermal diffusion of cement paste at elevated temperature. Results of the experiments can be used to predict the fire damaged temperatures of concrete, and to recommend proper methods for repair and rehabilitation.

지반의 열확산 특성은 지반을 구성하는 토립자와 공극을 이루고 있는 기체, 액체의 성질이 함께 반영되어 결정된다. 본 연구에서는 지표면에 일정한 열원이 가해지는 경우 지반의 구성성분에 따라 해당 지반에 나타나는 열확산 현상의 차이가 발생하고 이로 인해 지표면의 온도 변화에도 차이가 나타나는 점을 이용하여 지반의 구성성분 및 지층구조를 파악하는 방법에 대해 제안하고 있다. 암반위에 쌓인 건조 모래 지층의 두께에 따라 달라지는 지표면의 온도 변화를 적외선 화상과 온도계를 통해 측정하였고, 이를 수치해석 방법으로 검증하였다. 연구 결과 건조 모래층의 경우 깊이 10cm까지는 일정 열원에 의한 지표의 온도변화를 통해 지층의 깊이를 추정하는 것이 가능한 것으로 나타났다.

지반의 열확산 특성은 지반을 구성하는 토립자와 공극을 이루고 있는 기체, 액체의 성질이 함께 반영되어 결정된다. 본 연구에서는 지표면에 일정한 열원이 가해지는 경우 지반의 구성 성분에 따라 해당 지반에 나타나는 열확산 현상의 차이가 발생하고 이로 인해 지표면의 온도 변화에도 차이가 나타나는 점을 이용하여 지반의 구성성분 및 지층구조를 파악하는 방법에 대해 제안하고 있다. 암반위에 쌓인 건조 모래 지층의 두께에 따라 달라지는 지표면의 온도 변화를 적외선 화상과 온도계를 통해 측정하였고, 이를 수치해석 방법으로 검증하였다. 연구 결과 건조 모래층의 경우 깊이 10cm까지는 일정 열원에 의한 지표의 온도변화를 통해 지층의 깊이를 추정하는 것이 가능한 것으로 나타났다.