• Journal of Korean Society of Water and Wastewater
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• v.35 no.2
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• pp.113-120
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• 2021

High voltage impulse (HVI) has been gained attention as an alternative technique that could control the CaCO₃ scale problems encountered in water main, pipe, cooling tower and heat exchanger vessels. The aim of this study was to investigate the effect of electric field (E) and contact time (t) of HVI on reduction of Ca²⁺ concentration at two different temperatures of 25℃ and 60℃. A kinetic model on the effect of E and t was investigated too. As the E and t increased, the Ca²⁺ concentration decreased more than that of the control (= no HVI). The Ca²⁺ concentration decreased up to 81% at 15 kV/cm at 60℃, which was nearly 2 times greater than the control. With these experimental data-set of reduction of Ca²⁺ concentration under different E and t, the kinetic model was developed. The relationship between E and t required to reduce the concentration of Ca²⁺ by 30% was modeled at each temperature. The empirical model equations were; E^0.83· t = 60.3 at 25℃ and E^0.08· t = 1.1 at 60℃. These equations state the products of Eⁿ and t is always constant, which means that the required contact time can be reduced in accordance with the increment of E and vice versa.

• Journal of Climate Change Research
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• v.7 no.4
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• pp.433-442
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• 2016

In this study, we examine future changes in surface radiation associated with cloud amount and aerosol emission over East Asia. Data in this study is HadGEM2-CC (Hadley Centre Global Environmental Model version 2, Carbon Cycle) simulations of the Representative Concentration Pathways (RCPs) 2.6/4.5/8.5. Results show that temperature and precipitation increase with rising of the atmosphere $CO_2$. At the end of $21^{st}$ century (2070~2099) relative to the end of $20^{st}$ century (1981~2005), changes in temperature and precipitation rate are expected to increase by $+1.85^{\circ}C/+6.6%$ for RCP2.6, $+3.09^{\circ}C/+8.5%$ for RCP4.5, $+5.49^{\circ}C/10%$ for RCP8.5. The warming results from increasing Net Down Surface Long Wave Radiation Flux (LW) and Net Down Surface Short Wave Radiation Flux (SW) as well. SW change increases mainly from reduced total Aerosol Optical Depth (AOD) and low-level cloud amount. LW change is associated with increasing of atmospheric $CO_2$ and total cloud amount, since increasing cloud amounts are related to absorb LW radiation and remit the energy toward the surface. The enhancement of precipitation is attributed by increasing of high-level cloud amount. Such climate conditions are favorable for vegetation growth and extension. Expansion of C3 grass and shrub is distinct over East Asia, inducing large latent heat flux increment.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.209-216
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• 2014

The present study was conducted to estimate the NE values of corn, dried distillers grains with solubles (DDGS) and wheat bran (WB) for laying hens based on an indirect calorimetry method and nitrogen balance measurements. A total of 576 twenty-eight-wk-old Dwarf Pink-shell laying hens were randomly assigned to four groups fed a basal diet (BD) or a combination of BD with 50% corn or 20% DDGS or 20% WB, with four replicates each. After a 7-d adaptation period, each replicate with 36 hens were kept in one of the two respiration chambers to measure the heat production (HP) for 6 days during the feeding period and subsequent 3-d fasting. The equilibrium fasting HP (FHP) provided an estimate of NE requirements for maintenance (NEm). The NE values of test feedstuffs was estimated using the difference method. Results showed that the heat increment that contributed 35.34 to 37.85% of ME intake was not influenced by experimental diets (p>0.05) when expressed as Mcal/kg of DM feed intake. Lighting increased the HP in hens in an fed-state. The FHP decreased over time (p<0.05) with the lowest value determined on the third day of starvation. No significant difference between treatments was found on FHP of d 3 (p>0.05). The estimated AME, AMEn, and NE values were 3.46, 3.44 and 2.25 Mcal/kg DM for corn, 3.11, 2.79, and 1.80 Mcal/kg DM for DDGS, 2.14, 2.10, and 1.14 Mcal/kg DM for WB, respectively. The net availability of AME of corn tended to be numerically higher than DDGS and WB (p = 0.096). In conclusion, compared with corn, the energy values of DDGS and WB were overestimated when expressed on an AME basis.

• Journal of the Korean GEO-environmental Society
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• v.14 no.12
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• pp.53-60
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• 2013

A new type of reinforced earth wall(REW) system is developed with vegetated facing which provides proper environment for long-term vegetation and also applicable to high retaining wall system. Vegetated retaining wall is a green alternative for retaining walls and an effective way to reduce heat island effect than conventional block or concrete systems. Several construction sites using vegetated facing is observed to monitor adaptation state of vegetation and estimate surface temperature of wall facing over two years. It was observed that a number of plants including Siberian chrysanthemum adapt well to the inside of the facing blocks because vegetation bag helps to keep a proper condition for vegetation. According to the results using thermographic camera, average surface temperature of vegetated facing is higher for all ranges of coverage ratio of vegetation. The increment of average surface temperature of vegetated facing is larger than that of non-vegetated facing when the air temperature rises, and vice versa.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.519-528
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• 2002

It is not a rare occasion that certain dental procedures involving tooth reduction being peformed under inadequate water cooling due to a variety of reasons. This situation could possibly inflict the critical insult to the pulpal tissue of indicated tooth. The purpose of this experiment was to study the pattern of diffusion of external heat produced during routine dental procedures into the pulpal tissue. 30 stone blocks containing three lower second primary molars were used for certain restorative procedures and the temperature of the indicated tooth surface was measured by thermography(Inframetrics 600) and further used as a baseline data for the finite element analysis model fabrication designed in order to evaluate the pattern of thermal diffusion. The ranges of highest surface temperature measured from several dental procedures under water cooling and non-water cooling were $30.8^{\circ}C{\sim}43.6^{\circ}C$ and $51.2^{\circ}C{\sim}103.4^{\circ}C$ respectively. Among procedures studied, crown preparation showed the highest value and amalgam removal showed the lowest. Comparisons between data measured under water cooling and non-water cooling conditions have shown the statistically significant difference(p<0.05). All the non-cooling conditions have shown the relatively larger increment of temperature change at the pulp horn area than the cooling conditions. The results of this study strongly indicate that the water coolant is the essential element in restorative procedures for the maintenance of healthy pulp. Further related studies involving more procedures and conditions are recommended.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.211-217
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• 1984

To study affinity of proteolytic enzymes to soy proteins, the physicochemical and functional properties of enzymatically modified protein products, kinetic parameters and degree of hydrolysis were measured using trypsin, alcalase (serine type protease) and pronase. Bacterial alcalase and pronase showed much greater affinity to soy protein than animal intestinal trypsin. This effect was very significant when unheated soy isolate was used as a substrate. Specific activities of these enzymes decreased with the increment of substrate concentration (over 2.0%, w/v) when heat denatured soy protein was used as a substrate. However, the decrease in specific activity was negligible at substrate concentrations lower than 2.0%. Polyacrylamide gel electrophoretic results showed that the pattern of 2S protein band changed distinctly in alcalase hydrolysis as compared with those of trypsin and pronase. Protein solubilities of alcalase and pronase hydrolyzates increased by 25-30%, at their pI (pH 5.0) over the control. Virtually no change was observed in solubility by trypsin hydrolysis. Heat coagulability and calcium-tolerance of the protein increased by enzymatic hydrolysis. No clear tendency, however, was observed for emulsion properties, foam expansion and the amount of free -SH groups. The enzyme treatment considerably decreased foam stability.

• Journal of Aquaculture
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• v.19 no.2
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• pp.77-83
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• 2006

This study was conducted to investigate changes of hemolymph count, antioxidant enzyme activities (catalase: CAT and superoxide dismutase: SOD) and Heat Shock Protein 70 (HSP70) mRNA in hemolymph, hepatopancreas and gill of abalone (Haliotis sieboldii) exposed to various water temperatures. Abalones were exposed to 10, 15, 20, 25 or $30^{\circ}C$ for 0, 6, 12, 24 or 48 hours. Survival rate of abalone was 100% at 10, 15, 20 and $25^{\circ}C$, but 0% at $30^{\circ}C$. Hemolymph counts increased at lower water temperatures (10 and $15^{\circ}C$) and decreased at $30^{\circ}C$. SOD activity decreased immediately after exposure to lower or higher water temperatures compared to the control ($20^{\circ}C$) with an exception at $30^{\circ}C$ where the activity increased. At lower temperatures, SOD activity rose high after 24 hours, but decreased again at 48 hours. At $25^{\circ}C$, it decreased compared to the control. CAT activity decreased immediately after exposure to 10 or $25^{\circ}C$ compared to the control, and then was recovered to the initial level after increment. At $15^{\circ}C$, CAT activity was high after 6 hours, and then was recovered to the initial level after increment. At $30^{\circ}C$, the activity decreased throughout the experiment. The HSP70 mRNA expression in gill increased at lower temperatures compared to the control ($20^{\circ}C$) and $25^{\circ}C$. In this study, rapid change of wale, temperature caused stress response in abalone which had been raised at $20^{\circ}C$. At molecular level, HSP70 was expressed rapidly, but antioxidant enzymes like SOD and CAT were expressed later than HSP70. At 15 and $25^{\circ}C$ of water temperatures, the HSP70, SOD and CAT expression were stable with time. However, at $30^{\circ}C$, all abalone died possibly because they could not develop resistance to high temperature.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.4
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• pp.181-192
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• 2003

We developed a mathematical simulation model to portray the vertical distribution of soil water from the measured weather data and the known soil hydraulic properties, and then compared simulation results with the periodically measured soil water profiles obtained on Jungdong sandy loam to verify the model, In this model, we solved potential-based Richards' equation by the implicit finite difference method superimposed on the predictor-corrector scheme. We presumed that: soil hydraulic properties are homogeneous; soil water flows isothermally; hysteresis is not considered; no vapor flows; no heat transfers into the soil profiles; and water added to soil surface is distributed along the soil profile following partial displacement principle. The input data were broadly classified into two groups: (1) daily weather data such as rainfall, maximum and minimum air temperatures, relative humidity and solar radiation and (2) soil hydraulic data to approximate unsaturated hydraulic conductivity and water retention. Each hydraulic polynomial function approximated using the Chebyshev polynomial and least square difference technique in tandem showed a fairly good fit of the given set of data. Vertical distribution of soil water as approximations to the Richards' equation subject to changing surface and phreatic boundaries was solved numerically during 53 days with a comparatively large time increment, and this pattern agreed well with field neutron scattering data, except for the surface 0.1 m slab.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.286-296
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• 2016

Offshore CCS technology is to transport and inject $CO_2$ which is captured from the power plant into the saline aquifer or depleted oil-gas fields. The more accumulated injected $CO_2$, the higher reservoir pressure increases. The increment of reservoir pressure make a dramatic change of the operating conditions of transport and injection systems. Therefore, it is necessary to carefully analyze the effect of operating condition variations over the injection period in early design phase. The objective of this study is to simulate and analyze the $CO_2$ behavior in the transport and injection systems over the injection period. The storage reservoir is assumed to be gas field in the East Sea continental shelf. The whole systems were consisted of subsea pipeline, riser, topside and wellbore. Modeling and numerical analysis were carried out using OLGA 2014.1. During the 10 years injection period, the change of temperature, pressure and phase of $CO_2$ in subsea pipelines, riser, topside and wellbore were carefully analyzed. Finally, some design guidelines about compressor at inlet of subsea pipeline, heat exchanger on topside and wellhead control were proposed.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.314-319
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• 2013

In this study, nitrogen doped $TiO_2$ ($N-TiO_2$) coated on an activated carbon pellet (ACP) was prepared using sol-gel and the solid state heat treatment of urea to improve the removal property of volatile organic compounds (VOCs). To explore the visible light photocatalytic activity of the ACP under the light emitting diods (LED), the removal property of benzene gas was characterized by gas chromatography. The SEM and BET results show that the increment of titanium tetra isopropoxide contents leads to the increased $TiO_2$ coating amount of ACP surface and decreased specific surface area. From the results of benzene gas removal, the breakthrough time of ACP10 increased about 2 times compared to that of the ACP. The improved performance was attributed to the $N-TiO_2$ coating on ACP surface, which could be more effective to remove benzene gas under the condition of LED lamp.