• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.64-78
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• 2011

Surface of hydrophobic polyethylene membrane was modified to become hydrophilic by ion beam irradiation. Submerged membrane filtration reactors contained pristine membrane or surface-modified membrane and the influent to reactors was pickled radish wastewater. The objectives of this study was to investigate the variation of flux and pressure and the characteristics of pollutant removal such as organics, suspended solids and nutrients with time. The result of experiments using intermittent pristine membrane showed the occurrence of severe fouling by increasing permeate pressure rapidly in case of pickled radish wastewater but in synthetic wastewater, this phenomenon was not occurred. In experiments of variation flux after chemical cleaning and water cleaning in pristine membrane, chemical cleaning must be necessary for renewals of pollutant membrane. Performance of intermittent operation is higher than that of continuous operation. Reaching fouling time in the case of surface-modified membrane is 6 times as long as pristine membrane. According this reason, replacement expense of surface-modified membrane could be 1/6 of that of pristine membrane. Effluent from this process was relatively good water quality and performance in the removal efficiency of SS, nitrogen and phosphorus was particularly higher.

• Journal of Climate Change Research
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• v.3 no.2
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• pp.129-142
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• 2012

This study was carried out to evaluate carbon footprint during unhulled rice production and to compare mitigation technologies of methane, main carbon source during rice production, Carbon footprint of unhulled rice was a sum of $CO_2$ emission of agri-materials manufacture, rice cultivation and waste treatment. It was emitted 1.40 kg $CO_2$ during unhulled rice production, its distribution was 71.1% by $CH_4$ emission of rice cultivation, 11.8% of $N_2O$ emission by nitrogen application and 7.6% of complex fertilizer manufacture. $CH_4$ emission could be mitigated by some technologies; cultivation of the early maturing rice variety emitted lower by 44.4% than the mid maturing variety, intermittent drainage of submerged water by 43.8% than the continuous flooding condition, direct seeding by 32.0% than transplanting cultivation, no-ploughing by 20.9% than ploughing cultivation. It means that LCA on Global Warming Potential and the statistical data on innovated technical practice are key tools to systemize Measurable-Reportable-Verifiable (MRV) system for carbon footprint and carbon emission trade in the farm base.

• Journal of Ocean Engineering and Technology
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• v.32 no.6
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• pp.447-457
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• 2018

In this study, a two-dimensional fully nonlinear transient wave numerical tank was developed using a desingularized indirect boundary integral equation method. The desingularized indirect boundary integral equation method is simpler and faster than the conventional boundary element method because special treatment is not required to compute the boundary integral. Numerical simulations were carried out in the time domain using the fourth order Runge-Kutta method. A mixed Eulerian-Lagrangian approach was adapted to reconstruct the free surface at each time step. A numerical damping zone was used to minimize the reflective wave in the downstream region. The interpolating method of a Gaussian radial basis function-type artificial neural network was used to calculate the gradient of the free surface elevation without element connectivity. The desingularized indirect boundary integral equation using an isolated point source and radial basis function has no need for information about the element connectivity and is a meshless method that is numerically more flexible. In order to validate the accuracy of the numerical wave tank based on the desingularized indirect boundary integral equation method and meshless technique, several numerical simulations were carried out. First, a comparison with numerical results according to the type of desingularized source was carried out and confirmed that continuous line sources can be replaced by simply isolated sources. In addition, a propagation simulation of a $2^{nd}$-order Stokes wave was carried out and compared with an analytical solution. Finally, simulations of propagating waves in shallow water and propagating waves over a submerged bar were also carried and compared with published data.

• Applied Biological Chemistry
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• v.15 no.3
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• pp.241-249
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• 1972

The characteristic and efficiency of natural shell sand in the coast of Cheju-Do and Jin-Do were studied to apply as agricultural lime for the soil acid adjustment. 1. The alkalinity of shell sand from Cheju coast was higher than that of Jindo and more weathered into fine particles. The particle size distributions of Cheju shell sand were condensed finer particles than 32 mesh in Cheju shell sands and in more coarser particles than 32 mesh in Jindo one. 2. The effect of Cheju shell sand on increasing soil pH value in the upland condition was low at the beginning but more gradually increased after 8 weeks from the treatment than ground lime, and Jindo was very dull during the period of treatment. The commercial lime crushed from Jindo was approximately equal to the ground lime. 3. In the submerged condition, the shell sand of Cheju reacted with soil acid more quickly than ground lime after 2 days, and Jindo was very slow. 4. The relative efficiency of various particle size fraction of the shell sand was superior to the ground lime. The lime particles between 9 to 14 mesh and 20 mesh had more remarkable difference of pH value than other fine particles. The efficiency among finer sizes than 20 mesh particle was approximately equal to each others. 5. The shell sand from the Cheju would be applied directly as agricultural lime without any treatment, and Jindo also can be expected to be effective as agricultural lime with crushing procedure.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.161-170
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• 2007

A submerged biofilm sequencing batch reactor (SBSBR) process, which liquor was internally circulated through sandfilter, was designed, and performances in swine wastewater treatment was evaluated under a condition of no external carbon source addition. Denitrification of NOx-N with loading rate in vertical and slope type of sandfilter was 19% and 3.8%, respectively, showing approximately 5 times difference, and so vertical type sandfilter was chosen for the combination with SBSBR. When the process was operated under 15 days HRT, 105L/hr.m3 of internal circulation rate and 54g/m3.d of NH4-N loading rate, treatment efficiencies of STOC, NH4-N and TN (as NH4-N plus NOx-N) was 75%, 97% and 85%, respectively. By conducting internal circulation through sandfilter, removal performances of TN were enhanced by 14%, and the elevation of nitrogen removal was mainly attributed to occurrence of denitrification in sandfilter. Also, approximately 57% of phosphorus was removed with the conduction of internal circulation through sandfilter, meanwhile phosphorus concentration in final effluent rather increased when the internal circulation was not performed. Therefore, It was quite sure that the continuous internal circulation of liquor through sandfilter could contribute to enhancement of biological nutrient removal. Under 60g/m3.d of NH4-N loading rate, the NH4-N level in final effluent was relatively low and constant(below 20mg/L) and over 80% of nitrogen removal was maintained in spite of loading rate increase up to 100g/m3.d. However, the treatment efficiency of nitrogen was deteriorated with further increase of loading rate. Based on this result, an optimum loading rate of nitrogen for the process would be 100g/m3.d.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.339-346
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• 2014

To control populations of the chestnut weevil, Curculio sikkimensis Heller, the effects of various immersion temperatures and times on the chestnut weevil were tested. The effects of immersion treatments on chestnut fruits were also analyzed. The mortality levels of C. sikkimensis larvae were evaluated at various temperatures ($30^{\circ}C$, $35^{\circ}C$, $40^{\circ}C$, $45^{\circ}C$, and $50^{\circ}C$) and time intervals (1, 2, 3, 5, 7, 10, 15, 22, and 24 h). Changes in the chestnut fruit due to the immersion treatment were measured in terms of color (lightness, redness, and yellowness), physiological effects (germination rate and decay rate), hardness, and change in constituent properties (moisture content, free sugar content, and tannin content). Mortality levels of C. sikkimensis larvae after immersion treatment at $30^{\circ}C$ were over 70% and 100% after 2 h and 7 h, respectively. Color (lightness, redness, and yellowness) of the chestnut fruits was not significantly different at $30^{\circ}C$ and $35^{\circ}C;$ however, the color was affected at temperatures over $40^{\circ}C$. The germination rate of the fruit was not affected by the immersion treatments, but the decay rate at $40^{\circ}C$ increased with an increase in immersion time. The hardness of the fruits decreased with an increase in immersion times and temperatures. These results can be used in the future for developing methods for the control of chestnut weevil populations.

• Journal of Korean Society of Forest Science
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• v.43 no.1
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• pp.31-34
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• 1979

In this study, enzymatic hydrolysis of the substrate of the waste wood of Cortinellus edodes was investigated using crude cellulase preparation of Trichoderma viride Pers. ex. Fr. SANK 16374. The crude cellulase was produced by the submerged culture process and produced in the culture fluid was salted out quantitatively by the use of ammonium sulfate. Reducing sugar was determined by the dinitrosalisylic acid (DNS) method. 1. The chemical composition of the waste wood was crude protein 2.26%, c. fat 2.57%, c. fibre 44.60%, c. ash 5.58% and lignin 13.62%. In amino acid composition, no cystine and methionine was showed, but trace amount of Vitamin A, $B_1$, and $B_2$, niacine and chloride were detected. (Table 1) 2. As heat treatment of the substrate was found to produce the highest reducing sugar yield being reacted for 48hr. with T.v cellulase, the substrate was heated to $190{\pm}5^{\circ}C$. for 45 min. either before or immediately after milling. 3. The substrate heated and ball milled at $190{\pm}5^{\circ}C$. for 45 min. the reducing sugar yield reached to 11.5%. 4. The substrate without any treatment was found to produce the highest reducing sugar yield being reacted 72hr. with T. v cellulase, the reducing sugar yield reached to 10.1%. 5. The rate of reducing sugar per each treated substrate was decreased by the order of the substrated, heated and then ball milled at $190{\pm}5^{\circ}C$. for 45 min. (11.5%)> without any treatment (10.1)> ball milled and heated at $190{\pm}5^{\circ}C$. for 45 min. (6.9%). 6. Saccharification of waste wood has been shown to be possible by heat treated and milling the substrate in contact with cellulase. And it is likely to be recommended that the waste wood may be valuable for raw materials of saccharification.

• Journal of Korean Society of Forest Science
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• v.41 no.1
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• pp.1-6
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• 1979

1. The study was conducted on the optimum condition of the treated substrate with dilute sulphuric acid solution and cellulase for saccharification. The wood (saw dust) of Alnus hirsuta Rupr. (10~15 years) was treated with 0.3%, 0.6%, 0.9%, 1.2%, 1.5%, $H_2SO_4$ solution at $1.5kg/cm^2$ for 15min., 30min., 45min., and 60min., followed by thermal treatment at $190^{\circ}C$ for 30min., and screening with 60 mesh sieve, after which to 0.5 grams of each sample was added 0.5ml cellulase solution, and 50ml 0.1M acetic acid buffer solution (pH 5.0), after incubating at $40^{\circ}C$ for 96hr. 2. The crude cellulase of Trichoderma viride Perx. ex. Fr. SANK 16374 was produced by the submerged culture process and produced in the culture fluid was salted out quantitatively by the use of ammonium sulfite. 3. Reducing sugar was determined by the 3.5-dinitrosalicylic acid (DNS) method. 4. The reducing sugar was increased with increase of the sulphuric acid concentration and saw dust was treated with 1.5% $H_2SO_4$ solution at $1.5kg/cm^2$ for 45min. showed the best saccharification (16.0%). The reducing sugar formation did not show statistically significant in 5% levels by thermal treatment time 45min. and 60min. 5. The substrate for cellulase which was treated with 0.9% $H_2SO_4$ solution at $1.5kg/cm^2$ for 60min. showed the best reducing sugar formation (23.6%). And did not show significant difference in 5% levels at 0.9%, 1.2%, and 1.5% $H_2SO_4$ solution.

• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.425-430
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• 2011

Objectives: This in vitro study investigated whether short-term application of calcium hydroxide in the root canal system for 1 and 4 wk affects the fracture strength of human permanent teeth. Materials and Methods: Thirty two mature human single rooted mandibular premolars in similar size and dentin thickness without decay or restorations were hand and rotary instrumented and 16 teeth vertically packed with calcium hydroxide paste and sealed coronally with caviton to imitate the endodontic procedure and the other 16 teeth was left empty as a control group. The apicies of all the samples were sealed with resin, submerged in normal saline and put in a storage box at $37^{\circ}C$ to mimic the oral environment. After 1 and 4 wk, 8 samples out of 16 samples from each group were removed from the storage box and fracture strength test was performed. The maximum load required to fracture the samples was recorded and data were analysed statistically by the two way ANOVA test at 5% significance level. Results: The mean fracture strengths of two groups after 1 wk and 4 wk were similar. The intracanal placement of calcium hydroxide weakened the fracture strength of teeth by 8.2% after 4 wk: an average of 39.23 MPa for no treatment group and 36.01 MPa for CH group. However there was no statistically significant difference between experimental groups and between time intervals. Conclusions: These results suggest that short term calcium hydroxide application is available during endodontic treatment.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.1
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• pp.25-31
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• 1976

The purpose of this investigation is to find out the effects on the changes of microflora and the effects on the inorganic nutrients of the fertilized soil and the non-fertilized soil under submerged condition with the treatment of butachlor at the levels of 250, 500, and 1000ppm respectively. The survey was made within the period of 72 days with 7-day intervals under the incubated condition. The result came out to be the following: 1. The Fluctuated changes of soil microflora A. Bacteria: The plots treated by 500ppm of butachlor in case of non-fertilized soil showed the decreasing tendency of bacteria until 21st day. But there were no effects on the other plots. The plots treated by 250ppm and 500ppm in case of fertilized soil showed decreasing tendency on the 7th day, and 1000ppm until 21st days. B. Actinomycetes: There was no effects on the actinotnycetes in case of the non-fertilized soil but the fertilized soil showed some decrease. In both cases, actinomycetes have generally shown a little increase according to the time passage. C. Fungi: In both cases of the fertilized soil and the non-fertilized soil, the plots treated by the media showed some decreasing tendency in comparison with the control plots. There was no change to the number of fungi according to the time passage. 2. The fluctuated changes of nutrient A. $NH_4-N$: The whole plots showed decrease of $NH_4-N$ by adding butachlor. The higher the intencity of butachiar showed the more decreasing tendency of $NH_4-N$. In case of the non-fertilized soil, the highest increase of $NH_4-N$ appeared from the 7th day to 14th day, but showed degrease thereafter. The increasing tendency was seen in case of the fertilized soil plots. B. $NO_3-N$: Decrease of $NO_3-N$ was shown in the whole plots by the treatment of media, and on the 44th day of cultivation almost none of $NO_3-N$ was detected. C. $NO_2-N$: Whole plots showed the number of $NO_2-N$ highest on the 35th day, and there were nothing measurable on the 44th day. D. Eh: On the fertilized soil, the condition of reduction went on strongly but on the non-fertilized soil, the condition of reduction kept on till 42nd day and oxidation appeared thereafter.