• Fire Science and Engineering
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• v.31 no.6
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• pp.23-32
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• 2017

Foam block, popularized as the self-interior goods, is susceptible to fire since the main material is the polyethylene flammable synthetic resin. However, it is widely used in homes, offices, and multi-use facilities. In order to understand the fire characteristics of the foam block, two kinds of foam blocks sold in the market (non-fire retardant and fire retardant) were evaluated according to standard of KS F 5660-1 (Reaction to fire test). In addition, the hazard analysis of the gas generated by the combustion of the specimen was performed using the FTIR gas analyzer. The cone calorimeter test showed that the ignition and flame combustion of both two specimens were burned as soon as the radiant heat blocking device was removed, and it was confirmed that the flame could become a rapid propagation factor during the fire. The analysis of the combustion gas through the FTIR gas analyzer showed that both the carbon dioxide and carbon monoxide classified as the common combustion gases and the acrolein, ammonia, and hydrogen cyanide causing serious damage to the human body were detected substantially. This study showed that a foam block product has high ignitionability and generates toxic gases. Hence, it is urgently required to establish the standards used for properly classifying the combustion characteristics of the material on the basis of the use conditions of a foam block product and to prepare the standards on the purpose of use.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.6
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• pp.871-885
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• 2017

Nowadays, the construction of tunnels with a shallow depth drastically in urban areas increases. But the effect of sidewall displacement in shallow tunnel on its behavior is not well known yet. Most studies on the shallow tunnel have been limited to the stability and the failure of the tunnel and the adjacent ground in plane strain state. Therefore, the model tests were conducted in a model ground which was built with carbon rods, in order to investigate the impact of the tunnel sidewall displacement on the lateral load transfer to the adjacent ground. The lateral displacement of the tunnel sidewall and the load transfered to the adjacent ground were measured in model tests for various overburdens (0.50D, 0.75D, 1.00D, 1.25D). As results, if the cover depth of tunnel was over a constant depth (0.75D) in a shallow tunnel, the tunnel sidewall was failed with a constant shape not depending on the tunnel cover depth and also not affected by the opposite side of the wall. But, if the cover depth of tunnel was under a constant depth (0.75D), the failure of the tunnel sidewall could affect the opposite sidewall. In addition, if the displacement of tunnel sidewall with 50% of the critical displacement occurred, the tunnel failure was found to be at least 75%. However, additional studies are deemed necessary, since they may differ depending on the ground conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.979-984
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• 2011

Although sludge production has been increased due to the number of the wastewater treatment plants expanded, needs of the techniques for the sludge reduction and disposal has been issued importantly because the sludge dumping to ocean is prohibited from 2012 by the London Dumping Convention. Therefore, the sludge solubilization using electrolysis as an alternative techniques for the sludge disposal was carried out in this study. Iridium coated titanium based insoluble electrodes were used and 20 volt was applied to the electrolysis reactor using DC power supply. Supernatants of the treated sludge was monitored: The soluble COD, TN, TP of it was increased to 151%, 22% and 6% respectively. And the sludge floc size distribution was changed, that is, the flocs ranged from 0.1 to 1.0 ${\mu}m$ were increased. All of these results indicate that the cells were lysed and the internal matters bursted out of the cell after electrolysis. As well as the reduction of the sludge production, the soluble organic matters from the cells could be used as an external carbon sources in the advanced wastewater treatment plants.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.521-530
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• 2018

This paper proposes "The Agriculture Decision-making System(ADS) based on Deep Learning for improving crop productivity" that collects weather information based on location supporting precision agriculture, predicts current crop condition by using the collected information and real time crop data, and notifies a farmer of the result. The system works as follows. The ICM(Information Collection Module) collects weather information based on location supporting precision agriculture. The DRCM(Deep learning based Risk Calculation Module) predicts whether the C, H, N and moisture content of soil are appropriate to grow specific crops according to current weather. The RNM(Risk Notification Module) notifies a farmer of the prediction result based on the DRCM. The proposed system improves the stability because it reduces the accuracy reduction rate as the amount of data increases and is apply the unsupervised learning to the analysis stage compared to the existing system. As a result, the simulation result shows that the ADS improved the success rate of data analysis by about 6%. And the ADS predicts the current crop growth condition accurately, prevents in advance the crop diseases in various environments, and provides the optimized condition for growing crops.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.17-28
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• 2018

In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon In this study, catalytic activation using sulfuric acid lignin (SAL), the condensed solid by-product from saccharification process, with potassium hydroxide at $750^{\circ}C$ for 1 h in order to investigate its potential to nanoporous carbon material. Comparison study was also conducted by production of activated carbon from coconut shell (CCNS), Pinus, and Avicel, and each activated carbon was characterized by chemical composition, Raman spectroscopy, SEM analysis, and BET analysis. The amount of solid residue after thermogravimetric analysis of biomass samples at the final temperature of $750^{\circ}C$ was SAL > CCNS > Pinus > Avicel, which was the same as the order of activated carbon yields after catalytic activation. Specifically, SAL-derived activated carbon showed the highest value of carbon content (91.0%) and $I_d/I_g$ peak ratio (4.2), indicating that amorphous large aromatic structure layer was formed with high carbon fixation. In addition, the largest changes was observed in SAL with the maximum BET specific surface area and pore volume of $2341m^2/g$ and $1.270cm^3/g$, respectively. Furthermore, the adsorption test for three kinds of organic pollutants (phenol, 2,4-Dichlorophenoxyacetic acid, and carbofuran) were conducted, and an excellent adsorption capacity more than 90 mg/g for all activated carbon was determined using 100 ppm of the standard solution. Therefore, SAL, a condensed structure, can be used not only as a nanoporous carbon material with high specific surface area but also as a biosorbent applied to a carbon filter for remediation of organic pollutants in future.

• Ocean and Polar Research
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• v.29 no.2
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• pp.101-112
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• 2007

In order to examine the short-term variations of phytoplankton and heterotrophic protozoa community structures with bloom events, water samples were collected every other day at one site in the coastal water off Incheon, Korea, from August 15-September 30, 2001. $Chlorophyll-{\alpha}$ concentrations varied widely from 1.8 to $19.3\;{\mu}g\;l^{-1}$ with the appearances of two major peaks of $Chlorophyll-{\alpha}$ concentration during the study period. Size-fractionated $Chlorophyll-{\alpha}$ concentration showed that net-size fraction ($>20\;{\mu}m$) comprised over 80% of total $Chlorophyll-{\alpha}$ during the first and second bloom periods, nano-size fraction ($3{\sim}20\;{\mu}m$) comprised average 42% during the pre- (before the first bloom) and post-bloom periods (after the second bloom), and pico- size fraction ($<3\;{\mu}m$) comprised over 50% during inter-bloom periods (i.e. between the first and second bloom periods). Dominant phytoplankton community was shifted from autotrophic nanoflagellates to diatom, diatom to picophytoplankton, picophytoplankton to diatom, and then diatom to autotrophic nanoflagellates, during the pre-, the first, the inter, the second, and the post-bloom periods, respectively. During the blooms, Chaetoceros pseudocrinitus and Eucampia zodiacus were dominant diatom species composed with more than 50% of total diatom. Carbon biomass of heterotrophic protozoa ranged from 8.2 to $117.8\;{\mu}gC\;l^{-1}$ and showed the highest biomass soon after the peak of the first and second blooms. The relative contribution of each group of the heterotrophic protozoa showed differences between the bloom period and other periods. Ciliates and HDF were dominant during the first and second bloom periods, with a contribution of more than 80% of the heterotrophic protozoan carbon biomass. Especially, different species of HDF, thecate and athecate HDF, were dominant during the first and the second bloom periods, respectively. Interestingly, Noctiluca scintillans appeared to be one of the key organisms to extinguish the first bloom. Therefore, our study suggests that heterotrophic protozoa could be a key player to control the phytoplankton community structure and biomass during the study period.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.281-291
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• 2014

In March to August 2013, the emission of gases ($CH_4$, VOC, $CO_2$, $O_2$, and LEL) was measured three times from the intertidal flat sediments at Sogeun-ri, Taean-gun, in the Mid-western seashore of Korea by using chamber method. After analyzing gas emission concentrations inside of flux enclosure chamber by using a GC equipped with Agilent 6890. The gas emission fluxes were calculated from a linear regression of the changes in the concentrations with time. The ranges of gas flux during the experimental period were $+0.06{\sim}+0.60mg/m^2/hr$ for $CH_4$, $+58.45{\sim}+95.58mg/m^2/hr$ for $CO_2$, $-0.02{\sim}-0.20mg/m^2/hr$ for $O_2$, and $-0.60{\sim}+0.65mg/m^2/hr$ for VOC, respectively. The flux measurement results revealed that $CH_4$ fluxes during March in the relatively low sediment temperature ($14.5^{\circ}C$) were significantly higher ($+0.60mg/m^2/hr$) than during June and August ($+0.06{\sim}+0.18mg/m^2/hr$) in high sediment temperature ($32.0{\sim}36.8^{\circ}C$). $CH_4$ flux to mean size of sediments and temperature of inner chamber exhibited strong positive correlation ($R^2=-0.97$ and $R^2=-0.89$, respectively).

• Korean Journal of Organic Agriculture
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• v.10 no.3
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• pp.87-99
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• 2002

The development of insecticidal soaps made by various fatty acids and organic control for insect by using of insecticidal soap(fatty acid salts) were employed. And the results were as follows: 1. To determine the input volume of potassium hydroxide for saponification of fatty acids, there were compared to individual acid value of fatty acids. in case of coconut fatty acids for saponification was 266.3 mg of potassium hydroxide(266 g/1kg of fatty acid) was calculated. 2. To make the 25% soap content by coconut fatty acids, there was required for the 266g of potassium hydroxide and 3,459 liter of soft water. Then the liquor of soap was 4,644 liter. 3. The progress of insecticidal soap made by fatty acids was accomplished indirect heating and stirring reactor (1)to make the volume of potassium hydroxide solution and warming up(90$^{\circ}$) (2)input volume of individual fatty acid (3)more than 30 min stirring reaction (4)cooling progress. 4. Insecticidal value of insecticidal soap was observed more than 92% the dilution of 50 dilution solution in consecutive 5 days of 2 treatments of the 25% soap made by coconut fatty acids on the red pepper. And insecticidal value of insecticidal soap was observed more than 94% the 100 dilution solution in consecutive 5 days of 3 treatments of the 25% soap made by coconut fatty acids on red pepper and cabbage. 5. The treatment of two times of 25% soap made by coconut fatty acids at the 50 dilution solution and 100 dilution solution in spider mite on red bean has 100% insecticidal value. 6. There was no observation phytotoxic sypmtons on red pepper in field, except for 25% soap made by carprylic acid. 7. Over the two times over 0.1% in addition of isopropyl alcohol was to improvement the insecticidal effect, but there was no effect in addition of diatomaceous earth.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.37-43
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• 1992

Typhula incarnata grew over a temperature range of -5 to $20^{\circ}C$ with maximum growth at 10 to $15^{\circ}C$. Sclerotial production for T. incarnata was greatest at the higher temperature. Maximum mycelial growth of this pathogen occurred from pH 5.4 to 6.2. When carbon sources were added to a basal salt medium (Czapek's dox agar) at 5 g carbon sources/l, inulin, soluble starch, galactose, glucose, mannose, manitol, sucrose, maltose, cellobirose, trehalose, raffinose, and dextrin supported growth better than other carbon sources did. Of the twenty-three nitrogen sources tested, glycine, serine, ammonium sulfate, asparagine, asparatic acid, and ${\beta}-alanine$ were the most favorable for mycelial growth of T. incarnata. Cystine and cysteine were poor nitrogen sources. Ammonium salt of nitrogen sources supported growth better than nitrate salt of nitrogen sources. Potato dextrose agar, oat meal agar, and V-8 juice agar were the most favorable for mycelial growth and sclerotial formation. Appropriate addition of pepton to PDA decreased mycelial dry weight, but sucrose supported good growth of T. incarnata. Percent viable sclerotia of T. incarnate buried in bentgrass soil decreased from 2 months after treatment remarkably. Trichoderma riride and bacteria were isolated from non-germinated sclerotia. Live orchard grass leaf pieces within the soil were colonized by T. incarnata better than sterile and unsterile dead leaf pieces at $0^{\circ}C$. Saprophytic ability of T. incarnate on sterile leaf sheath occurred better at $0^{\circ}C$ than at $10^{\circ}C$. Saprophytic microflora consisting of Cladosporium sp., Fusarium sp., Mucor sp., Pythium sp., and unidentified fungi were the competitors for the sterilized and unsterilized substrate, but their colonization was not find on live leaf sheath buried in the soil at $0^{\circ}C$. In the effect of fungicides to Typhula snow mold disease of creeping bentgrass, mixture of polyoxin and thiram was the most effective, followed by iprodione, mixture of iprodione and oxine copper, thiophanate-methyl, myclobutanil, and tolclofos-methyl.

• Korean Journal of Organic Agriculture
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• v.26 no.1
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• pp.99-128
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• 2018

The cultivation area of rice as staple grains is decreasing in the domestic situation in Korea. Import volume of a duty in foreign rice is 409,000 tons for a year regardless increasing of production per unit area and decreasing of rice consumption. The total stock of rice is increasing cumulatively despite the effort for production mediation of rice. Therefore, maintenance of cultivation area and reduction of production are necessary for national foodstuffs security problems. Development of environment-friendly and low-carbon technology as alternative of global warming and aging of farm labor power is very important responsibility for descendants with creation of sustainable agriculture environment. As alternative for demand and supply stabilization of rice from all angles, first stage: extension of environment-friendly cultivation area as 17% Jeollanam-do level with maintenance of cultivation area under the present circumstances, second stage: extension of environment-friendly cultivation area as 25%, third stage: extension of environment-friendly cultivation area as 35%. From above mentioned scenario, reduction of rice production (60,000 tons), increases of production cost (59,200,000,000 Won), and reduction of income (201,500,000,000 Won) are estimated in first stage. Reduction of rice production (90,000 tons), increases of production cost (122,100,000,000 Won), and reduction of income (313,700,000,000 Won) are estimated in second stage. Reduction of rice production (380,000 tons), increases of production cost (222,000,000,000 Won), and reduction of income (464,500,000,000 Won) are estimated in third stage. From analysis results for partial tillage in transplanting cultivation complex (10ha), rice production is decreased 1.3~1.5 ton by complex. Production cost of rice is decreased and increases of income cultivation type. Gradual extension of environment-friendly agriculture and low-carbon partial tillage could be expected for environment maintenance of the territorial integrity, confidence of consumer, and high-efficiency of low-cost.