• Journal of Korean Society of Forest Science
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• v.39 no.1
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• pp.64-68
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• 1978

Thirty nine clones of ${\times}$Populus alba glandulosa were selected tentatively and planted in Hwasung in Kyunggi-do, Jinju in Kyungnam-do, Myongju in Kangweon-do. Height measurements after tree growing seasons, indicated significant differences between clones and locations. Interaction between clones and locations were not significant statistically. Among 39 clones, 65-29-19, 65-11-106, 67-47-10, 66-14-149, 64-6-44 were best performing clones. Height measurements in Hwasung Kyunggi, and Jinju Kyungnam were 3.83m, 4.02m respectively, while that in Myongju Kangweon was only 1.06m. Myongju plantation in Kangweon-do is located in altitude of 800m and its average annual temperature was $6.2^{\circ}C$. Retarded growth in this plantation is caused high altitude and low temperature of the plantation which resulted from nearly three monthes shorter growing period than two other plantations. It is also recommended that straightness of stem, branching, wood quality and insect and disease-resistance have to be considered as selection criteria along with growth performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.7
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• pp.711-719
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• 2012

A thermodynamic analysis and a feasibility study on the organic Rankine cycle (ORC) as a waste heat recovery system for a marine diesel engine were carried out. The ORC and its combined cycle with the engine were simulated, and its performance was estimated theoretically using R245fa. A parametric study on the performance of the ORC system was carried out under different temperature conditions of the heat transfer loop and specification of the heat exchanger. According to the thermodynamic analysis, ~10% of the thermal efficiency of the cycle was able to be realized with the low temperature heat source below $250^{\circ}C$. The electric power output of the ORC was estimated to be about 4% of the mechanical power output of the engine, considering additional pumps for cooling water and circulation of the heat transfer medium. According to the present study, the electric power generated by the ORC is about 59%-69% of the required power, and it is possible to reduce the fuel consumption under normal seagoing conditions.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.333-336
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• 2013

Experimental investigation to estimate the feasibility of fast selective catalytic reduction (SCR) or oxidation catalyst combined ammonia SCR system to abate NOx in low temperature condition ($150{\sim}250^{\circ}C$) is reported. Because the conversion of NO to $NO_2$ is pre-requisite of the fast SCR process, the effect of the amount of oxidation catalyst to NO conversion to $NO_2$ was tested. 37, 45 and 51% of conversion rates were obtained for the OCV of 563000, 375000 and 281000 h, respectively. $De-NO_x$ performance in the case of $NO_2/NO_x$ ratio of 45% showed the best result in all tested temperature conditions. Comparison of the fast SCR and standard SCR with the condition of $NO_2/NO_x$ ratio of 45%, $200{\sim}250^{\circ}C$ and space velocity of 10000~30000 h showed that the fast SCR does not show much difference according to the variance of space velocity. Also it was shown that using the fast SCR, the volume of SCR catalyst can be reduced less than half of the standard SCR condition by increasing space velocity without the loss of $De-NO_x$ performance.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.143-150
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• 2015

The objective of this study was to evaluate the effects of different litter mixture compositions on bedding system temperature, pH and volatile fatty acid and ammonia-N ($NH_3$-N) content, and the serum physico-chemical parameters and growth indices of calves. Thirty-two Limousin calves ($280{\pm}20kg$) were randomly assigned to four groups (n = 8 for each group) according to the bedding system used: i) control with soil only (CTR); ii) mixture with 50% paddy hulls (PH), 30% saw dusts (SD), 10% peat moss (PM) and 10% corn cobs (CC) (TRT1); iii) mixture with 15% PH, 15% SD, 10% PM, 40% CC, and 20% corn stover (CS) (TRT2); iv) mixture with 30% PH, 10% PM, 40% CC, and 20% CS (TRT3). The litter material combinations of different treatments were based on the cost of bedding system materials in China. The cost of four treatments from low to high: Control$NH_3$-N level (271.83 to 894.72 mg/kg) was lowest for TRT1 (p<0.0001) and highest for TRT2 (p<0.0001). The acetate, propionate and butyrate levels were highest for the control group (p<0.0001). In all the groups, the pH value (6.90 to 9.09) increased at the beginning and later remained stable at below 9.09. The temperature of deep litter increased at the first week and reached the maximum ($42.1^{\circ}C$) on day 38. 3,5,3'-Triiodothyronine ($T_3$) levels in the TRT1 group animals (p<0.0001) were lower than those in the control and TRT2 animals. 3,5,3',5'-Tetraiodothyronine ($T_4$) in the TRT1 group (p = 0.006) was lower than that in the other treatment groups. Cortisol (COR) in the control and TRT1 group was lower (p<0.0001) than that in the TRT2 and TRT3 groups. Corticosterone (CORt) in the control group was higher (p<0.0001) than that in the treatment groups. The findings indicate that the deep litter bedding systems provided better conditions for animal health and growth performance compared with the control system. Furthermore, the litter composition of TRT1 was found to be optimal among the three treatment groups.

• Membrane Journal
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• v.24 no.3
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• pp.201-212
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• 2014

This study was performed to discover the optimum operation conditions for the advanced water treatment using the ceramic membrane, introduced the first in the nation at the Y water treatment plant (WTP). The result of investigation to find the optimum operation conditions which can continue preserving the filtration performance as well as satisfying both the economics and the water quality is as follows. In the ordinary water quality condition of the Y WTP, the optimum filtration time(the backwash period), which can minimize the production of backwash waste and preserve the membrane performance was examined to be 4.0 hours on basis of institution capacity ($16,000m^3/day$). Examining the recovery rate of TMP from the chemical cleaning (CIP) discovered that the inorganic contaminants, which cause membrane fouling, such as iron, manganese, aluminum, were removed through the acidic cleaning using citric acid, whereas the membrane recovery rate was found to be low. But, on the other hand, the TMP was recovered to the initial value from the alkali cleaning using the NaOCl. Therefore, the main contaminant causing the fouling was determined to be hydrophilic organic compound( biopolymer). The membrane recovery rate is highly influenced by the temperature of the cleaning chemical. That is, the rate increased with increasing temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.588-595
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• 2020

This study examined the catalytic property of Ni-catalyst used in the gas purifying process to manufacture inert gases of N2 and Ar with high-purity over 9N for semiconductor industrial applications. Two types of Ni-catalysts with a cylindrical shape (C1) and churros shape structure (C2) were compared for the assessment. Optical microscopy and FESEM were used to analyze the shape and microstructure of the Ni-catalyst. EDS, XRD, and micro-Raman characterization were performed to examine the composition and properties. BET and Pulse Titration analyses were conducted to check the surface area and catalytic property of the Ni-catalyst. From the composition analysis results, C1 contained a relatively large amount of graphite as an impurity, and C2 contained higher Ni contents than C1. From specific surface area analysis, the specific surface area of C2 was approximately 1.69 times larger than that of C1. From catalytic property analysis, outstanding performance in O₂ and CO impurity removal was observed at room temperature. Therefore, C2, having low-impurity and large specific surface area, is a suitable catalyst for the high-purity inert gas process in the semiconductor industry because of its outstanding performance in O₂ and CO impurity removal at room temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.465-472
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• 1994

To improve the germination performance of rice seeds under suboptimal temperature, osmopriming with PEG-6000 was examined. Optimal PEG-6000 concentration to improve germination was 20% PEG-6000 solution, and rice cultivars used in this experiment were Sinunbongbyeo, Gancheokbyeo, Dongjinbyeo. The water content of seeds after soaking for 60 hours in the PEG solution is similar to that of seeds after soaking for 24 hours in the distilled water. Germination performance of the soaked seeds in the PEG solution was higher than that of the soaked seeds in the distilled water or the control, especially under suboptimal temperatures. Electrical conductivity of the soaked seeds in the PEG solution was lower than that of the soaked seeds in the distilled water or the control, and total dehydrogenase activity of the soaked seeds in the PEG solution was higher than that of the soaked seeds in the distilled water or the control. SDS-PAGE results of soluble protein from the embryos of seeds primed differently showed darker band in the seeds soaked in the PEG solution than the seeds soaked in the distilled water or the control at the 68 KD region. Also, band patterns of peroxidase and esterase of embryos soaked in the PEG solution were darked than that of embryos soaked in the distilled water or the control at the Rf 0.94 and Rf 0.87, respectively.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.1-12
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• 2009

A new mix design procedure for cold in-place recycling using foamed asphalt (CIR-foam) has been developed for Iowa Department of Transportation. Some strengths and weaknesses of the new mix design parameters were considered and modified to improve the laboratory test procedure. Based on the critical mixture parameters identified, a new mix design procedure was developed and validated to establish the properties of the CIR-foam mixtures. As part of the validation effort to evaluate a new CIR-foam mix design procedure, dynamic moduli of CIR-foam mixtures made of seven different reclaimed asphalt pavement (RAP) materials collected throughout the state of Iowa were measured and their master curves were constructed. The main objectives of this study are to provide: 1) standardized testing procedure for measuring the dynamic modulus of CIR-foam mixtures using new simple performance testing (SPT) equipment; 2) analysis procedure for constructing the master curves for a wide range of RAP materials; and 3) impacts of RAP material characteristics on the dynamic modulus. Dynamic moduli were measured at three different temperatures and six different loading frequencies and they were consistent among different RAP sources. Master curves were then constructed for the CIR-foam mixtures using seven different RAP materials. Based upon the observation of the constructed master curves, dynamic moduli of CIR-foam mixtures were less sensitive to the loading frequencies than HMA mixtures. It can be concluded that at the low temperature, the dynamic modulus is affected by the amount of fines in the RAP materials whereas, at the high temperature, the dynamic modulus is influenced by the residual binder characteristics.

• Tunnel and Underground Space
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• v.32 no.1
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• pp.59-77
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• 2022

Currently, the design reference temperature of the buffer material for disposing of high-level radioactive waste is less than 100℃, so if the heat dissipation capacity of the buffer material is improved, the spacings of the disposal tunnel and the deposition hole in the repository can be reduced. First of all, this study tries to analyze the criteria for thermal-hydraulic-mechanical performance of the buffer materials and to investigate the researches regarding the enhanced buffer materials with improved thermal conductivity. First, the thermal conductivity should be as high as possible and is affected by dry density, water content, temperature, mineral composition, and bentonite type. the organic content of the buffer material can have a significant effect on the corrosion performance of a canister, so the organic content should be low. In addition, hydraulic conductivity of the buffer material should be less than that of near-field rock and swelling pressure should be appropriate for buffer materials to function properly. For the development of enhanced buffer materials, additives such as sand, graphite, and graphite oxide are typically used, and a thermal conductivity can be greatly improved with a very small amount of graphite addition compared to sand.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.555-566
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• 2023

In this study, a composite phase change material (CPCM) produced using the SOL-GEL technique was developed as a thermal energy storage medium for low-temperature applications. Tetradecane and activated carbon (AC) were used as the core and supporting materials, respectively. The tetradecane phase change material (PCM) was impregnated into the porous structure of AC using the vacuum impregnation method, and a thin layer of silica gel was coated on the prepared composite using the SOL-GEL process, where tetraethyl orthosilicate (TEOS) was used as the silica source. The thermal performance of the CPCM was analysed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC results showed that the pure tetradecane PCM had melting and freezing temperatures of 6.4℃ and 1.3℃ and corresponding enthalpies 226 J/g and 223.8 J/g, respectively. The CPCM exhibited enthalpy of 32.98 J/g and 27.7 J/g during the melting and freezing processes at 7.1℃ and 2.4℃, respectively. TGA test results revealed that the AC is thermally stable up to 500℃, which is much higher than the decomposition temperature of the pure tetradecane, which is around 120℃. Moreover, in the case of AC-PCM and CPCM thermal degradation started at 80℃ and 100℃, respectively. The chemical stability of the CPCM was studied using Fourier-transform infrared (FT-IR) spectroscopy, and the results confirmed that the developed composite is chemically stable. Finally, the surface morphology of the AC and CPCM was analysed using scanning electron microscopy (SEM), which confirmed the presence of a thin layer of silica gel on the AC surface after the SOL-GEL process.