• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.553-558
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• 2010

This study was conducted to clarify the differences in rodents population densities between natural restored and red pine silvicultured forests after forest fire in Samcheok, Gangwon Province, Korea from March to December 2008. One ha size of 3 study plots were set up in each natural restored and silvicultured stand. We trapped the small rodents during 4 consecutive nights every 2 months in each stand. Understory coverage and number of shrub stems were higher in silvicultured stand than in natural restored stand. Coverage of overstory, suboverstory and midstory, number of tree stem, woody seedling stems and dead wood, and amount of coarse woody debris were higher in natural restored stand than in silvicultured stand. Six hundred eighty eight individuals of four species, such as Apodemus agrarius, A. peninsulae, Eothenomys regulus and Tamias sibiricus were captured in our study. Number of captured small rodents were higher in natural restored stand than in silvicultured stand. Also, species compositions were differed in both stands. The captured number of A. agrarius and A. peninsulae were most highest in April and December. E. regulus were shown higher number of captured in April and June, and T. sibiricus were in June and October. Removal of coarse woody debris and silvicultural practice would not be good for the inhabitation of small rodents. For the conservation of small rodents diversity, management of understory and canopy would be needed in forest fired area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.590-596
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• 2019

Uses of fossil fuels like coal and oil increases with industrial development, and problems like abnormal climate come up as greenhouse gas increases. Accordingly, studies are actively conducted on eco-friendly renewable energy as a replacement for the main resources, and especially, wood pellets with high thermal efficiency are in the limelight as an alternative fuel in thermal power stations and gas boilers. However, despite a constant increase in their usage, few studies are conducted on their risks like fire and spontaneous combustion. Thus, this study found the auto-ignition temperature and critical ignition temperature of wood pellets with a change in flow rate in a thermostatic bath, using a sample vessel with 20 cm in length, 20 cm in height and 14 cm in thickness to predict their ignition characteristics. Consequently, at the flow rate of 0 NL/min, as the core temperature of the sample increased to higher than the ambient temperature, they ignited at $153^{\circ}C$, when the critical ignition temperature was $152.5^{\circ}C$. At the flow rates of 0.5 NL/min and 1.0 NL/min, it was $149.5^{\circ}C$, and at the flow rate of 1.5 NL/min, it was $147.5^{\circ}C$. Consequently, at the same storage, the more the flow rate, the lower the critical ignition temperature became.

• Resources Recycling
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• v.25 no.6
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• pp.73-81
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• 2016

Geopolymers produced from aluminosilicate materials such as metakaolin and coal ash react with alkali activators and show higher fire resistance than portland cement, due to amorphous inorganic polymer. The percentage of thermal shrinkage of geopolymers ranges from less than 0.5 % to about 3 % until $600^{\circ}C$, and reaches about 5 ~ 7 % before melting. In this study, geopolymers paste having Si/Al = 1.5 and being mixed with carbon nanofibers, silicon carbide, pyrex glass, and vermiculite, and ISO sand were studied in order to understand the compressive strength and the effects of thermal shrinkage of geopolymers. The compressive strength of geopolymers mixed by carbon nanofibers, silicon carbide, pyrex glass, or vermiculite was similar in the range from 35 to 40 MPa. The average compressive strength of a geopolymers mixed with 30 wt.% of ISO sand was lowest of 28 MPa. Thermal shrinkage of geopolymers mixed with ISO sand decreased to about 25 % of paste. This is because the aggregate particles expanded on firing and to compensate the shrinkage of paste. The densification of the geopolymer matrix and the increase of porosity by sintering at $900^{\circ}C$ were observed regardless of fillers.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.57-66
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• 2019

This study carried out on-site investigation and precision monitoring to prepare proper design and operation technical guidelines for the use of bio gas in organic waste resources (fertilizing urine, food waste, food waste, food waste, etc.). According to the government's mid- and long-term policy on bio gasification, the expansion of waste resources is actively being pushed forward. However, facilities that use the biogas produced for urban gas and transportation are still under-efficient. Precision monitoring was carried out for biogasification facilities of organic waste resources in seven locations nationwide. When the results of precision monitoring were summarized with the four-season average, the efficiency analysis of each organic waste resource showed that the organic breakdown rate was 66.3% on average on VS basis. Analysis of biogas characteristics before and after pretreatment revealed that the $H_2S$ average of the entire facility was measured at 949.7 ppm using iron salts and desulfurization (dry, wet) and that the quality refining facility shearing and rear end was 29.0 ppm and 0.3 ppm. The methane content was found to be reduced by 65.6% at the rear of the fire tank, 63.5% at the back and 97.5% at the rear.

• Resources Recycling
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• v.28 no.6
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• pp.64-72
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• 2019

Fly ash has different chemical composition depending on the type and quality of flaming coal. Fly ash is classified according to carbon content and particle size. Waste glass powder is manufactured by crushing glass. Exterior Insulation Finish System (EIFS) is generally applied by using poly-styrene foam which is economical and has excellent thermal insulation performance. However, poly-styrene foam has excellent insulation performance, but it is vulnerable to fire, which is becoming a serious problem. In this study, using a fly ash and waste glass powder to produce a finishing mortar at high temperatures. Also, High temperature strength and flame retardant properties were tested according to the cover thickness. From the test result, finishing mortar prepared using fly ash and waste glass powder is due to the improved heat resistance by alkali-activated bonding. However, since the strength decreases at high temperatures, it is necessary to select an appropriate mixing proportion.

• Korean Journal of Plant Resources
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• v.21 no.1
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• pp.87-90
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• 2008

The purpose of this experiment is to understand a possibility for the techniques of collecting the Korean Rhus lacquer by the traditional method(Hwachil) against the diminishing lacquer industry. Hwachil method, making use of fire to collect lacquer, is practiced at only some areas, but the lacquer is very efficacious for foods and oriental medicine. A comparative experiment between traditional method and new machine method by processing unit 5 kg of lacquer tree was made to improve Hwachil method technically. The results showed that the machine method produced more about 45% of lacquer than the traditional one. The traditional method, moreover, needed intense labour quality and high leveled techniques, which caused to bring physical sufferings. In comparison with the traditional method for the collecting time required, the machine one showed to take more than minutes per a unit. But the machine method was easy and convenient to handle the machine without special techniques.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.4
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• pp.128-135
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• 2012

Autoclaved lightweight concrete, also known as autoclaved aerated concrete(AAC) or autoclaved cellular concrete (ACC), is made with fine silica powder, quik lime, cement, and an Al powder. ALC contains 70~80% air. The lightweight material offers excellent sound and thermal insulation, and like all cement-based materials, is strong and fire resistant. However, ALC have high water absorption, low compressive strength and popout the origin of the low surface strength in its properties. These properties make troubles under construction such as cracking and popout. Thus, this study is to improve the fundamental strength by controls of increasing of admixtures, gypsum and silica powder size. Admixtures make use of metakaolin and silica fume. From the test result, the ALC using admixture have a good fundamental properties compared with plain ALC. Compressive strength, specific strength and abrasion's ratio were improved depending on increasing admixtures ratio's, gypsum and silica powder size.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.2
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• pp.177-184
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• 2017

Many ground subsidence accidents have happened in Korea. The accident was caused by the subsidence and leakage of the deteriorated sewage pipe. This study aims to establish the empirical data of the ground penetration radar(GPR) detection for ground subsidence. A test bed was also manufactured for the same purpose. The GPR detection variables are embedment depth and horizontal distance of embedded cast iron pipe and expanded polystyrene(EPS). From the detection results, the EPS embedded by a depth of 1.5m was difficult for detection. The EPS closely embedded to the cast iron pipe within a 0.5m distance had a very strong cast iron pipe signal. Therefore, the detection was impossible. This study developed an image processing program, called the GPR image processing program(GPRiPP), to process the GPR detection results. Its major function is the gain function, which amplifies the wiggle wave signal. Compared to the existing programs, the GPRiPP is capable of showing a similar image processing performance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.43-52
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• 2016

The coniferous fallen leaf is one of the major forestry residues. Since the coniferous fallen leaf would not be easily decayed, the large amount of the coniferous fallen leaves in forestry could be the source of forest fire. The applicability of the fallen leaves to the pulp mold were evaluated for developing new utilization of coniferous fallen leaves. The morphological properties and the chemical composition of the fallen leaves of Pinus densiflora and Pinus koraiensis were evaluated by the comparison with those of fresh leaves. The applicability of the coniferous fallen leaves to the pulp mold and the effects on the pulp mold properties including the scent diffusion were investigated. The fallen leaves showed the shrunk structure by losing the hot water extract component, which leaded to better grinding properties than that of fresh leaves. The pulp mold with fallen leaves showed higher strength properties than the pulp mold with fresh leaves. Although the scent of the pulp mold with fresh leaves was stronger, the pulp mold with fallen leaves had coniferous scent too. The application of fallen leaves to pulp mold for the functional properties could be possible by improving the mechanical properties and the scent lasting treatments.

• Journal of Forest and Environmental Science
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• v.31 no.4
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• pp.312-316
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• 2015

Rhizina undulata, the causal agent of Rhizina root rot, is a soil-borne fungus occurring on coniferous trees. The destruction of coastal forests caused by R. undulata infection has been mainly associated with bonfires at camping sites. However, Rhizina root rot was observed in the western coastal forests without fire. It was hypothesized that Rhizina root rot in this area might be closely related to the soil salinity, which can facilitate the growth and survival of R. undulata. So, the variation in sodium chloride (NaCl) resistance among isolates of Rhizina undulata was compared using liquid media containing different concentrations of NaCl ranging from 0 mM to 300 mM. Our results showed that, albeit of no growth at a higher concentration of NaCl (300 mM), most of R. undulata isolates were capable of germinating and grew at up to 100 mM, indicating that NaCl resistance varies among R. undulata isolates. It was further found that isolates from coastal areas seemed to be more tolerant to NaCl than those further away the coast. We demonstrated that R. undulata could be possible to survive in coastal areas, but was lower NaCl tolerance than other fungi.