• Fire Science and Engineering
• /
• v.33 no.2
• /
• pp.9-19
• /
• 2019

Experiments on the combustion characteristics of untreated wood specimens and those treated with four types of silicone compounds were carried out using a cone calorimeter according to the ISO 5660-1 standard. 3-Aminopropyltrimethoxysilane (APTMS), 3-(2-aminoethylamino) propylmethyldimethoxysilane (AEAPMDMS), and 3-(2-aminoethylamino) propyltrimethoxysilane (AEAPTMS) were used as the silane compounds. The flame retardants were synthesized with sodium silicate and amino silane compounds. The measured time to ignition after combustion at an external heat flux of $50kW/m^2$ was 9 s to 11 s. Time to ignition was marked with a delayed value in the 3 s to 5 s range. The peak heat release rate ($HRR_{peak}$) was reduced by 5 to 20% compared with the uncoated specimen, and AEAPMDMS showed the highest initial fire risk. The total heat release (THR) was decreased by 1 to 22%. Compared to the untreated specimen, the fire performance index (FPI) of the specimens coated with silicone sol compounds increased by 1.5 to 2.2 fold. The fire growth index (FGI) of the AEAPMDMS specimen was increased by 30% and the others were decreased by 93 to 94%. Therefore, the fire risk of wood coated with silicone compounds was improved in terms of the heat risk properties.

• Clean Technology
• /
• v.24 no.4
• /
• pp.323-331
• /
• 2018

The results of an experimental investigation on the co-firing characteristics and slagging behavior of dried and hydrothermal carbonization sewage sludge, sub-bituminous coal, and wood pellet in a fluidized bed were presented. Combustion tests were conducted in a lab-scale bubbling fluidized bed system at the uniform fuel-air equivalence ratio, air flow rate, and initial bed temperature to measure bed temperature distribution and combustion gas composition. 4 different fuel blending cases were prepared by mixing sewage sludge fuels with coal and wood pellet with the ratio of 50 : 50 by the heating value. $NO_x$ was mostly NO than $NO_2$ and measured in the range of 400 to 600 ppm in all cases. $SO_2$ was considered to be affected mostly by the sulfur content of the sewage sludge fuels. The cases of hydrothermal carbonization sewage sludge mixture showed slightly less $SO_2$ emission but higher fuel-N conversion than the dried sewage sludge mixing cases. The result of fly ash composition analysis implied that the sewage sludge fuels would increase the possibility of slagging/fouling considering the contents of alkali species, such as Na, K, P. Between the two different sewage sludge fuels, dried sewage sludge fuel was expected to have the more severe impact on slagging/fouling behavior than hydrothermal carbonization sewage sludge fuel.

• Korean Journal of Heritage: History & Science
• /
• v.49 no.4
• /
• pp.114-125
• /
• 2016

Lacquer is one of the most widely used natural resin in East Asia since Neolithic Age. As a major ingredient of lacquerware, lacquer is waterproof, insect-proof and rot-proof to be durable and anti-abrasion, generally utilized for mainly painting purpose. According to lacquerware excavated from several sites of Japan and China, lacquerware seems to appear in Neolithic Age. On the other hand in case of excavation research in Korea, lacquerwares are found after the Bronze Age. The initial purpose of lacquer is estimated to be adhesive, regarding the literatures mentioning bitumen(Yeoksceong ), animal glue(Kyeo) and egg alumen(Nanbaek). Especially piece of jar coffin unearthed in Pyeongtaek Daechu-ri site had trace of restoration by lacquer and hemp as an evidence of lacquer for adhesion in Pre-Three Kingdoms period. Since then a trend to restore the broken ceramics with lacquer and decorate with golden foil lasted especially in Joseon Dynasty. In the field of gold plated lacquer method, mother-of-pearl inlaying technique for lacquerware and restoration of buildings, lacquer is still used as adhesive. Due to matter of reversibility lacquer is being avoided for conservation and restoration of cultural heritage. Lacquer as a traditional material for adhesive since ancient times, however, has advantage in adhesion strength and durability. Because synthetic resin adhesive has problem of emission of volatile organic compounds and aging over time, lacquer receives attention recently. On the contrary, by combination adhesive from mixing lacquer and animal glue, already proved the possibility of applicability and chemical modification. A research to utilize lacquer as modern paint or functional material is also conducted continuously also in China and Japan. To put traditional material into practical use and modernize, chemical research from the molecular level of the lacquer is necessary in the near future.

• Korean Journal of Heritage: History & Science
• /
• v.51 no.2
• /
• pp.124-137
• /
• 2018

Although the evaluation system for excavation reports has been in operation for over 10 years, there has been no research on the evaluation system. First, this study examined the changes of the evaluation system, and secondly, it analyzed the evaluation factors affecting the evaluation results. As a result of institutional analysis, the present evaluation result is being utilized in PQ, and it is suggested that the evaluation subject institution is limited to the excavation institution, which may cause disadvantages to the participating museums. We also pointed out that a small number of jury members are currently evaluating the report and therefore need to reinforce it to ease the burden of assessment. As a result of evaluation factor analysis, it was confirmed that the target score was lower but the actual effect score was higher. In addition, it suggested that the indicators should be improved because the report system, headings, natural archaeological environment, scope and method of survey, and editing and printing indicators are less influential than other indicators. In addition, we conducted a regression analysis of each group by examining the appropriateness of classification amounts according to current excavation costs. As a result of the analysis, the cost of excavation in the second and third groups in 2015 and 2016 was found to affect the score. This emphasized the need for an in-depth approach to estimating the taxonomic value of the group, which is inconsistent with the initial objective of not affecting the assessment results according to excavation costs.

• The Journal of the Korea Contents Association
• /
• v.19 no.5
• /
• pp.381-388
• /
• 2019

In South Korea nowadays, Among the married immigrant women in Korea, the proportion of long-term residents living in Korea for more than 10 years is increasing continuously(48%), while the proportion of short-term residents who are under 5 years is decreasing(16%). However, Korean language education and related research in the Marriage and Immigration Women's Center are still focused on the initial immigrants. Therefore, we should classify married immigrant women according to their stay time in Korea, so that Korean language education and teaching materials need to be more diversified. This study focuses on married immigrant women with intermediate and advanced Korean proficiency and chooses a catalogue of Chinese characters idioms to explore the possibility and educational value of using Chinese characters Idioms in Korean education. According to the research results, Chinese characters idiom education can help married immigrant women in Korean language learning and information acquisition, interpersonal relationships and life attitudes, cultural understanding and social adaptation, child rearing and learning guidance. This is the important part of Korean language education that needs to be guided by married immigrant women. Based on this, 130 Chinese characters idioms in Korean language education and textbook development centered on married immigrant women were selected and catalogue edited in four stages. It is hoped that the results of this study will serve as a reference for Korean language education research and textbook development for married immigrant women in the future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.30 no.3
• /
• pp.252-259
• /
• 2019

Jet engine modulation(JEM) signals are widely used in the field of target recognition along with high-range resolution profile and inverse synthetic aperture radar because they provide specific information of the jet engine. To obtain the number of blades of the jet engine, the chopping frequency proportional to the number of blades must be extracted. In the conventional chopping frequency extraction method, an initial threshold value is defined and a method of detecting the chopping peak is used. However, this detection method takes time depending on the signal due to repetitive detection. Thus, in this study, we proposed to extract the chopping frequency using MUltiple SIgnal Classification(MUSIC) algorithm. We applied the MUSIC algorithm to a given JEM signal to find the chopping frequency and determine the blade number candidates. We also applied the MUSIC algorithm to other chopping frequency extractions to determine the score of the candidate groups. Unlike the conventional detection algorithm, which requires repetitive frequency detection, MUSIC algorithm quickly detects the accurate chopping frequency and reduces the calculation time.

• Clean Technology
• /
• v.27 no.2
• /
• pp.182-189
• /
• 2021

The adsorption of disperse yellow 3 (DY 3) on granular activated carbon (GAC) was investigated for isothermal adsorption and kinetic and thermodynamic parameters by experimenting with initial concentration, contact time, temperature, and pH of the dye as adsorption parameters. In the pH change experiment, the adsorption percent of DY 3 on activated carbon was highest in the acidic region, pH 3 due to electrostatic attraction between the surface of the activated carbon with positive charge and the anion (OH^-) of DY 3. The adsorption equilibrium data of DY 3 fit the Langmuir isothermal adsorption equation best, and it was found that activated carbon can effectively remove DY 3 from the calculated separation factor (R_L). The heat of adsorption-related constant (B) from the Temkin equation did not exceed 20 J mol^-1, indicating that it is a physical adsorption process. The pseudo second order kinetic model fits well within 10.72% of the error percent in the kinetic experiments. The plots for Weber and Morris intraparticle diffusion model were divided into two straight lines. The intraparticle diffusion rate was slow because the slope of the stage 2 (intraparticle diffusion) was smaller than that of stage 1 (boundary layer diffusion). Therefore, it was confirmed that the intraparticle diffusion was rate controlling step. The free energy change of the DY 3 adsorption by activated carbon showed negative values at 298 ~ 318 K. As the temperature increased, the spontaneity increased. The enthalpy change of the adsorption reaction of DY 3 by activated carbon was 0.65 kJ mol^-1, which was an endothermic reaction, and the entropy change was 2.14 J mol^-1 K^-1.

• Korean Journal of Agricultural Science
• /
• v.47 no.4
• /
• pp.845-857
• /
• 2020

The precise estimation of accelerated soil wind erosion that can cause severe economic and environmental impacts still has not been achieved to date. The objectives of this investigation were to verify the applicability of a Wind Erosion Prediction System (WEPS) that expressed the soil loss as mass per area for specific areas of interest on a daily basis for a single event in arable lands. To this end, we selected and evaluated the results published by Hagen in 2004 and the soil depth converted from the mass of soil losses obtained by using the WEPS. Hagen's results obtained from the WEPS model followed the 1 : 1 line between predicted and measured value for soil losses with only less than 2 kg·m-2 whereas the values between the measured and predicted loss did not show any correlation for the given field conditions due to the initial field surface condition although the model provided reasonable estimates of soil loss. Calculated soil depths of the soil loss by wind for both the observed and predicted ones ranged from 0.004 to 3.113 cm·10 a-1 and from 0 to 2.013 cm·10 a-1, respectively. Comparison of the soil depths between the observed and predicted ones did not show any good relationship, and there was no soil loss in the predicted one while slight soil loss was measured in the observed one. Therefore, varying the essential model inputs and factors related to wind speed and soil properties are needed to accurately estimate soil loss for a given field in arable land.

• Applied Chemistry for Engineering
• /
• v.22 no.6
• /
• pp.617-622
• /
• 2011

Ozone-based advanced oxidation was applied for the treatment of anaerobic digestion effluent of livestock wastewater. Initial COD and color value were 930 mg/L and 0.04, respectively, and the 1/10-diluted wastewater was used for the study. The treatment characteristics were compared between the conventionally generated ozone ($105{\mu}m$) and microbubbled ozone ($13{\mu}m$). The use of microbubbled ozone improved the removal of chemical oxygen demand (COD) and color by 85% and 26%, respectively, compared with the conventionally bubbled ozone. The application of microbubbled $O_3/UV$, $O_3/H_2O_2$, $O_3/UV/H_2O_2$ combinations resulted in 5~10% higher color removal than ozone alone, which implies that the contribution of UV or $H_2O_2$ is not significant in color removal. On the other hand, COD removal could be increased two folds compared with ozone alone through $O_3/UV/H_2O_2$ combination. The contribution of $H_2O_2$ was bigger than UV for COD removal with microbubbled ozone. Due to the enhancement of dissolved ozone and radical activity, the microbubbling enabled us to additional COD removal even after stopping ozone supply in the presence of UV or $H_2O_2$.

• Journal of agriculture & life science
• /
• v.53 no.3
• /
• pp.41-49
• /
• 2019

Consumers are interested in natural ingredient that replace synthetic antioxidants in meat products. This study was carried out to investigate the effects of astaxanthin (AX) on the oxidative stability and quality characteristics of emulsified sausages during cold storage. Emulsified sausages were prepared as follows: manufactured without AX and BHT (Control), added with 500 mg/kg of BHT (BHT), and added with 80 mg/kg of AX (AX). Addition of AX showed no significant difference in pH, emulsion stability and cooking yield of emulsified sausages (p>0.05). However, the initial color retentivity was the same as that of synthetic antioxidant such as BHT treatment, and the redness was higher when AX treatment was added (p<0.05). The lipid oxidation showed the lowest value in the BHT treatment at the end of storage and the AX treatment also was significant lower than that of control (p<0.05). Hardness was lower in the all treatments at the end of storage than in the control (p<0.05). Therefore, astaxanthin can be used as a color enhancing agent for meat products as well as an natural antioxidant in replacing of BHT which is as synthetic antioxidant.