• Journal of Soil and Groundwater Environment
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• v.22 no.6
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• pp.112-119
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• 2017

In this study, the availability of cow manure as raw material for solid fuel production was investigated. Since the water content of the cow manure was too high, it was dewatered using a laboratory hydraulic compressure ($11.3kg/cm^2$). The moisture content of the cow manure decreased from 82.01% to 73.36 wt.%. The dewatered cow manure was homogenized by the experimental apparatus and then put into the rotating cylindrical apparatus. From the consecutive processes, the cow ball-shaped pellet which size ranged from 3.0 to 25.0 mm was produced. The major factor for making palletized fuel from cow manure was the moisture content. Based on the experimental data, the moisture content of cow manure for pelletizing cow manure was identified as 65~75 wt.%. When the moisture content of the cow manure was lower than 30 wt.%, the diameter of the pellets maded from cow manure was smaller than 3 mm. On the other hand, when the water content of the cow manure was higher than 75 wt/%, the diameter of the processed pellets tended to be larger than 25 mm. The characteristics of the processed cow manure pellets was analyzed to be in accordance with the livestock solid fuel quality standard. The pyrolysis characteristic of the pellet was analyzed by raising the heating temperature of the experimental equipment from 200 to $900^{\circ}C$. The mass change between of 20 and $130^{\circ}C$ corresponds to the amount of moisture contained in the cow manure. The amount of moisture was about 15% of the total weight of cow manure samples. The cow manure pellet was thermally stable up to $280^{\circ}C$. It can be interpreted that combustion of cow manure pellet does not occur until the surface temperature reaches $280^{\circ}C$. The mass change of pellet between of 280 and $450^{\circ}C$ was considered to be due to the vaporization of volatile organic compounds (VOCs) present in the cow manure pellet. The maximum production of VOCs was showed near $330^{\circ}C$.

• Applied Chemistry for Engineering
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• v.32 no.2
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• pp.197-204
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• 2021

This study investigated the smoke risk assessment of woods and plastics for construction materials, focusing on the smoke performance index-V (SPI-V), smoke growth index-V (SGI-V), and smoke risk index-VI (SRI-VI) according to a newly designed methodology. Spruce, Lauan, polymethylmethacrylate (PMMA), and polycarbonate (PC) were used for test pieces. Smoke characteristics of the materials were measured using a cone calorimeter (ISO 5660-1) equipment. The smoke performance index-V calculated after the combustion reaction was found to be 1.0 to 3.4 based on PMMA. Smoke risk by smoke performance index-V was increased in the order of PC, Spruce, Lauan and PMMA. Lauan and PMMA showed similar values. The smoke growth index-V was found to be 1.0 to 9.2 based on PMMA. Smoke risk by smoke growth index-V increased in the order of PMMA, PC, Spruce, and Lauan. COpeak production rates of all specimens were measured between 0.0021 to 0.0067 g/s. In conclusion, materials with a low smoke performance index-V and a high smoke growth index-V cause a high smoke risk from fire. Therefore, it is understood that the smoke risk from fire is high. It is collectively summarized by the smoke risk index-VI.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.403-412
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• 2021

Despite strengthening requirements for fire retardancy and applied buildings of insulation panels, the number of fires and influence of damage have increased. In this study, the thermal effects were evaluated as the separation distances, and three types of EPS panel, glass wool panel, and gypsum board panel were then selected. Temperature sensors on the panels were installed vertically from the ground. The fire source on the lamination layer of lumber was ignited by changes in the separation distances (0 cm, 25 cm, 50 cm) from the panels. The test results suggested that the maximum temperature was 349 ℃ in the EPS panel. The inside/outside shape changes were limited by the height of the low and middle positions until the critical point of a 25 cm separation distance. Furthermore, the combustion marks appeared after 500 s on average, and then the EPS panel with a high fire strength showed a broad "U type" pattern, glass wool panel, and gypsum board panel showed medium or narrow "V type" pattern. Therefore, the acquired data can provide valuable information for evaluating the fire risks and verifying fire investigation from buildings composed of these insulation panels.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.331-335
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• 2018

The purpose of this study is to investigate the feasibility of CFBC artificial fine aggregate as a substitute for natural aggregate used in dry mortar. The basic performance of the flow, compressive strength and dry shrinkage of the dry mortar was evaluated. Four types of test dry mortar specimens using natural aggregate without expansion admixture, a specimen with modified CaO expansion admixture and natural aggregate, a specimen with modified CaO expansion admixture and CFBC artificial fine aggregate, and a specimen using CFBC artificial fine aggregate without modified CaO expansion admixture were evaluated respectively. As a result of evaluation of drying shrinkage performance at 20th day of age, the dry shrinkage performance of the specimen using modified CaO expansion admixture was found to be the highest at $250{\times}10^{-6}$. On the other hand, the specimen containing the modified CaO expansion admixture with CFBC artificial aggregate exhibited a shrinkage of $410{\times}10^{-6}$, and the drying shrinkage of specimen using natural fine aggregate without expansion admixture was $450{\times}10^{-6}$. When the modified CaO expansion material was used, and exhibited performance equal to or higher than that of the shrinkage-drying property.

• Composites Research
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• v.32 no.5
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• pp.199-205
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• 2019

The composite material has the advantage that the fibers can be arranged in a desired direction and can be manufactured in one piece. However, micro voids can be formed due to micro air, moisture or improper curing temperature or pressure, which may cause the deterioration in mechanical strength. In this paper, the composite panels with different thicknesses were made by varying the curing pressure in an autoclave vacuum bag process and their microporosities were evaluated. Microporosity was measured by image analysis method, acid digestion method, and combustion method and their correlation with ultrasonic attenuation coefficient was analyzed. From the test results, it was found that the acid digestion method had the highest accuracy and the lower the curing pressure, the higher the microporosity and the ultrasonic attenuation coefficient. In addition, the microporosity and the ultrasonic attenuation coefficient were increased as the thickness of the composite panel was increased at the same curing pressure.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.75-82
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• 2021

This study investigated the fire risk assessment of woods and plastics for construction materials, focusing on the fire performance index-III (FPI-III), fire growth index-III (FGI-III), and fire risk index-IV (FRI-IV) by a newly designed method. Japanese cedar, red pine, polymethylmethacrylate (PMMA), and polyvinyl chloride (PVC) were used as test pieces. Fire characteristics of the materials were investigated using a cone calorimeter (ISO 5660-1) equipment. The fire performance index-III measured after the combustion reaction was found to be 1.0 to 15.0 with respect to PMMA. Fire risk by fire performance index-III increased in the order of PVC, red pine, Japanese cedar, and PMMA. The fire growth index-III was found to be 0.5 to 3.3 based on PMMA. Fire risk by fire growth index-III increased in the order of PVC, PMMA, red pine, and Japanese cedar. COpeak concentrations of all specimens were measured between 106 and 570 ppm. In conclusion, it is understood that Japanese cedar with a low bulk density and PMMA containing a large amount of volatile organic substances have a low fire performance index-III and high fire growth index-III, and thus have high fire risk due to fire. This was consistent with the fire risk index-IV.

• Journal of the Society of Disaster Information
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• v.18 no.2
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• pp.324-332
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• 2022

Purpose: In order to conduct a spontaneous ignition test in which a fire occurs in the absence of an ignition source due to the oil adsorbed on the towel. A phenomenon in which spontaneous ignition occurs when adsorbed to fibers using flaxseed oil, which is drying oil and olive oil, which is non-drying oil, is tested through an experiment. Method: After placing the sample container in the experimental device, observe the change in the central temperature of the sample, and when the central temperature rises above the set temperature and a fire occurs, it is judged as "ignition", and the experiment is stopped after checking the maximum value of the central temperature of the sample,When the central temperature of the sample was maintained similar to the set temperature, it was judged as "non-ignition" and the experiment was stopped. Result: In the towels with adsorbed flaxseed oil, the temperature in the sample container increased rapidly and combustion occurred in sheets 5, 10, and 15. Olive oil is a non-drying oil, does not ignite because it is difficult to dry because carbon is a single bond and it is difficult to bond with oxygen. Conclusion: It was confirmed that the more the amount of towel adsorbed to the drying oil, flaxseed oil, the longer the time to reach the set temperature and the occurrence of ignition.

• Resources Recycling
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• v.31 no.4
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• pp.3-11
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• 2022

Owing to the increasing demand for electric vehicles (EVs), appropriate management of their waste batteries is required urgently for scrapped vehicles or for addressing battery aging. With respect to technological developments, data-driven diagnosis of waste EV batteries and management technologies have drawn increasing attention. Moreover, robot-based automatic dismantling technologies, which are seemingly interesting, require industrial verifications and linkages with future battery-related database systems. Among these, it is critical to develop and disseminate various advanced battery diagnosis and assessment techniques to improve the efficiency and safety/environment of the recirculation of waste batteries. Incorporation of lithium-related chemical substances in the public pollutant release and transfer register (PRTR) database as well as in-depth risk assessment of gas emissions in waste EV battery combustion and their relevant fire safety are some of the necessary steps. Further research and development thus are needed for optimizing the lifecycle management of waste batteries from various aspects related to data-based diagnosis/classification/disassembly processes as well as reuse/recycling and final disposal. The idea here is that the data should contribute to clean design and manufacturing to reduce the environmental burden and facilitate reuse/recycling in future production of EV batteries. Such optimization should also consider the future technological and market trends.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.574-580
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• 2022

Purpose: As corn oil is semi-drying oil, it has more double bonds than non-drying oil and is easier to combine with oxygen. In addition, among the causes of spontaneous ignition, accidents caused by oil-soaked cloths due to oxidative heat are gradually increasing. Therefore, the purpose of this study is to understand the characteristics of spontaneous combustion according to the number of towels and the amount of corn oil at 65℃. Method: After setting the test temperature to 65℃, 25ml, 50ml, 75ml of corn oil per towel was sprayed. The central temperature of the sample rises above the set temperature. It was determined, and when the central temperature of the sample became similar to the set temperature, it was determined as non-igniting. Result: After evenly distributing 25ml of corn oil per towel, as a result of the experiment, 5 towels did not ignite, and 10 and 15 towels ignited. Also, as a result of an experiment using 50ml and 75ml of corn oil per towel, spontaneous ignition occurred when the number of towels was 5, 10, or 15 sheets. Conclusion: Even a small amount can cause a fire if the conditions for spontaneous ignition are met.

• Tribology and Lubricants
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• v.39 no.2
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• pp.49-55
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• 2023

Currently, the demand for green technologies toward a sustainable future is rapidly increasing due to growing concern over environmental issues. Methanol is biodegradable and can provide clean combustion to reduce sulfur oxide and nitrogen oxide emissions, and therefore it is a candidate fuel for marine engines. However, the effect of methanol on tribological characteristic degradation should be addressed for methanol-fueled engines. In this study, the methanol addition effects on tribological characteristic degradation is experimentally assessed using a pin-on-disk tribo-tester. Ni-based alloy is used as a target material due to its broad applicability as an engine component material. For a lubricant, engine oil with and without methanol are used. The tests are conducted for up to 10,000 cycles under boundary lubrication while the change in friction force is monitored. Additionally, the wear rate is determined based on laser scanning confocal microscope data. An additional test in which methanol is added at regular intervals is performed with an aim to directly observe its effect on friction. Overall, the friction coefficient increases slightly with increasing methanol concentration. Furthermore, the wear rate of the pin and disk increase significantly with methanol addition. The results also indicate that the friction increases instantaneously with methanol addition at the contacting interface. These findings may be useful for better understanding the methanol effect on the tribological characteristics of Ni-based alloys for methanol-fueled engines with improved performance.