• Nuclear Engineering and Technology
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• v.26 no.2
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• pp.179-189
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• 1994

A performance of reactor coolant pump in two-phase flow is examined using the pump geometric conditions and the performance of the pump in single-phase flow. Wall friction loss of the reactor coolant pump in single-phase flow is prdicted using the Truckenbrodt boundary layer theory, and the head loss in two-phase flow is predicted with calculated well friction loss and separation loss coefficients. The analysis results are compared with the Combustion Engineering pump test data. The effect of two-phase multiplier on the peak clad temperature in Loss-of-Coolant Accident is also examined using the RELAP5 and the results indicate the importance of its accuracy.

• Composites Research
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• v.36 no.2
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• pp.86-91
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• 2023

Thermoplastic polyurethane (TPU) is a material whose mechanical properties change according to the phase separation of its unique internal microstructure and is therefore used in various industries. Use of TPU as composites helps in improving the desirable characteristics and properties in accordance with usage. Eco-friendly fillers one of the fillers are on the rise and those are mostly used for reinforcing role. Suberin, which can be extracted from cork, is the main component of cork. It is known to serve high damping property of elastomer composite. The original chemical structure of Suberin is an aliphatic polyester aggregate. In this research, Suberin is obtained after depolymerization into an oligomer having 2 or 3 ester bonds through alkaline hydrolysis. The extracted suberin was added to the matrix which is thermoplastic polyurethane as an eco-friendly filler for improving vibration damping property. As a result, when 10 wt% of suberin was added into thermoplastic polyurethane the existing trade-off relationship was overcome. And it is attained the elastic modulus and damping factor at room temperature improving 92 and 59%, respectively, compared to the original matrix. Those results are from the interaction between the microstructure of TPU and suberin.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.58.4-59
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• 2020

We present preliminary results of 1.1 and 1.3 mm dust continuum and 12CO (J=2-1) line data obtained with the Submillimeter Array toward six cores harboring Class 0/I objects in the λ Orionis cloud. They are located in bright rimmed clouds, which are exposed to the far-ultraviolet radiation field by the O-type star λ Ori. Compact dust continuum emission is observed from all six cores. Among the six cores, only one core G196.92-10.37 shows a signature of binarity with separation of 4000 AU. The numbers of singles and binaries in our sample are five and one, respectively and the derived multiplicity frequency (MF) is 0.17. This value is lower than those found in the binary surveys toward Class 0/I objects, which may be a hint for negative feedback by the nearby massive star, lambda Ori. The derived excitation temperature (Tex) using 12CO emission shows a lower median value (20 K) than those of triggered star-forming regions (30 K). The lower MF and Tex support our previous study that star formation was not triggered in the λ Orionis cloud. We aim to further investigate whether the Class 0/I YSOs in the λ Orionis cloud have less circumstellar materials and smaller accretion rates than in other filamentary clouds (e.g., Orion A & B), which might be attributed to negative feedback from the massive star in limiting accretion of protostars.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.6.1-6.9
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• 2024

The document is a white paper on Hydrophilic Interaction Liquid Chromatography (HILIC) analysis method development. HILIC is a type of chromatography that uses an organic/aqueous mobile phase and a polar stationary phase. In HILIC, water is a strong solvent, and unlike in Reversed Phase Liquid Chromatography (RPLC), increasing the proportion of water in the mobile phase reduces the retention time of the analyte. The paper discusses when to consider HILIC analysis methods, the advantages of HILIC, and the challenges often encountered due to the lack of understanding of HILIC mechanisms compared to RPLC. It also provides a systematic flowchart for intelligent solutions for HILIC analysis method development, which includes a three-step approach for chromatography analysis method development. The first step involves gathering as much information as possible about the analyte (e.g., pKa, log P, log D). The second step involves analyzing the sample under different pH conditions using three HILIC columns in either isocratic or gradient mode to identify the suitable column/pH combination for the analyte. The third step involves optimizing the separation by investigating other parameters such as temperature and ionic strength, and assessing the robustness of the method. The paper emphasizes that the selection of the appropriate stationary/mobile phase combination, based on the differences between the HILIC stationary phases and the mobile phase pH, can provide high selectivity in the analysis. This step-by-step approach can help users develop an efficient analysis method.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.6
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• pp.980-989
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• 2009

Amur cork tree was extracted in methanol with the purpose of investigating the most effective extraction procedure for detecting the chromophore using the GC-MS analysis. Different procedures of waterbath and hotplate extractions were carried out and five different GC-MS instrument parameters including the operating temperatures in the GC capillary column and the MSD scan range were tested for their efficiencies. Berberine was determined by the detection of dihydroberberine at 15.0 min r.t. Hotplate was a better device for extracting amur cork tree than waterbath shaker either with or without presoaking in the room temperature. Water was not an adequate extraction medium for the berberine detection. The most effective GC-MS parameter was Method 4; the initial temperature at $50^{\circ}C$ followed by the temperature increase of $23^{\circ}C$/min until $210^{\circ}C$, then increase of $30^{\circ}C$/min until the final temperature reach at $305^{\circ}C$, then hold for 14 minutes to maintain the total run time 24.12 minutes. The MSD scan range for Method 4 was $35\sim400$m/z.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.424-429
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• 2018

In this study, an expansion joint that is susceptible to waterhammer was tested for its vibration durability. The operation data for the hydraulic actuator was the expansion length of the expansion joint when the waterhammer occurred. In the case of the vibration durability test, the internal temperature status of the expansion joint was assumed to be a stress factor and a lifespan prediction model was assumed to follow the Arrhenius model. A test was carried out by increasing the internal temperature status at $30^{\circ}C$, $50^{\circ}C$, and $65^{\circ}C$. By a linear transformation of the lifespan data for each temperature, a constant value and activation energy coefficient was induced for the Arrhenius equation and verified by comparing the value of a lifetime prediction model with the experimental value at $85^{\circ}C$. The failure modes of the ongoing or finished test were leakage, bellows separation, and internal deformation. In the future, a composite lifespan prediction model, including two more stress factors, will be developed.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.704-714
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• 2005

Phase separations of Poly(4-vinylphenol)(PVPh)/Ethyl Acetate and PVPh/Butyl Acetate solutions were measured using the thermal optical analysis (TOA) method. The experimental phase separation data were correlated with liquid-liquid equilibria relations based on PC-SAFT equation of state. The phase separations of these system showed the behaviors of LCST (lower critical solution temperature)-type. The measured cloud temperatures were lowered with increasing in molecular weights of polymer(PVPh), and cloud temperatures of PVPh/Ethyl Acetate solutions shifted to lower temperature regions, compared to the PVPh/Butyl Acetate solutions. Extents of cross-association between solvent molecule and polymer in the PVPh/Ethyl Acetate solutions were measured using the FT-IR spectrum analysis method, and cross-association parameters of PC-SAFT model were estimated from experimental extents of cross-association. By using the estimated cross-association parameters between PVPh and solvent molecule, binodal and spinodal curves of liquid-liquid equilibria in PVPh/Ethyl Acetate and PVPh/Butyl Acetate solutions were calculated from PC-SAFT equation of state. The calculated binodal curves of these system were shown to be well agreeable with the experimental cloud temperature curves.

• Korean journal of food and cookery science
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• v.28 no.6
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• pp.805-811
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• 2012

This study was carried out in order to optimize the manufacturing condition of fried garlic flakes as well as to investigate the physicochemical properties of the flakes. Fried garlic flake samples were prepared as follows: garlic was sliced by a thickness of 1.5 mm, 2.0 mm, 2.5 mm, which were measured by a thickness gage. The samples were fried in vegetable oil under different temperatures of $140{\sim}150^{\circ}C$, $160{\sim}170^{\circ}C$ and $180{\sim}185^{\circ}C$. The compression strength depending on the height (h) was measured in order to find the thickness effect by the rheometer (force control: 50 N, h: 3.25 mm). Moreover, the sample with 1.5 mm thickness showed crisp phenomena of the split compared with the crush shape of the 2.0 mm and 2.5 mm thick samples. The result of strength for time dependence showed a sample with a thickness of 1.5 mm, which was measured 5~9 times more than the 2.0 mm and 2.5 mm thick samples. We thought the reason that the 1.5 mm sample had less response power equivalent to compression force than the other samples. Alliin has been found to affect the immune responses in the blood, it is a derivative of the amino acid cysteine and is also quite heat stable. The LC system with a UV detection at 210 nm consists of a separation on a Zorbax TMS column and isocratic elution with water and ACN as a mobile phase. The alliin contents of raw and fried garlic flake under $140{\sim}150^{\circ}C$, $160{\sim}170^{\circ}C$ and $180{\sim}185^{\circ}C$ were 18.10 mg/mL, 14.0 mg/mL, 11.6 mg/mL and 11.1 mg/mL, respectively. The decrement of alliin content under different temperature was a small quantity hence, we confirmed that the increasing manufacturing temperature was not affected by the alliin content. Examining for the particle structure of fried garlic flakes by a polarization microscope, the color of the sample treated at $160{\sim}170^{\circ}C$ was pure yellow. Furder, the fiber shaped particle, which has an effect on the tough texture, almost did not appear compared to the different temperature conditions. Finally, the sensory test for the preference of fried garlic flake under different conditions was carried out and the scores for various sensory characteristics were surveyed. According to the physicochemical measurements and sensory evaluation, we confirmed that the optimum manufacturing condition of fried garlic flake was 1.5 mm thick at a temperature of $160{\sim}170^{\circ}C$.

• Journal of fish pathology
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• v.9 no.2
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• pp.147-155
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• 1996

This study was carried out to examine the acute toxic effects of ammonia to the eel, Anguilla japonica in high temperature and pH levels by histopathological observations. The eels of 40 g average body weight were exposed to 4 different concentrations of total ammonia (0, 10, 20, 30 mg/$\ell$) for 24~120 hours. Each concentration was treated under 4 different levels of pH (7.5, 8.0, 8.5, 9.0) and each of these treatments was tested at 2 different temperatures ($27^{\circ}C$, $32^{\circ}C$). Histopathological changes in gill tissues were observed by hematoxylin-eosin stain. As increasing of pH (from 7.5 to 9.0), water temperature (from $27^{\circ}C$ to $32^{\circ}C$), total ammonia concentration (from 0 mg/$\ell$ to 30 mg/$\ell$) and exposure time (from 24 hours to 120 hours), gill discolorated to dark brown with the naked eye and gill tissues showed hypertrophy of gill lamellae, winding of the secondary gill lamellae, epitherial separation and necrosis histopathologically. When gill lamellae epithelium was separated from the blood vessels, gill discolorated to dark brown with the naked eye.

• Journal of the Korean Ceramic Society
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• v.38 no.11
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• pp.967-972
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• 2001

The crystal and defect structures of U $O_{x}$(x=2.0, 2.03, 2.14, 2.19, 2.20 and 2.26) were analysed by rietveld refinement and the results were compared to the U-O phase diagram. Neutron diffraction data were collected in the temperature range of RT~100$0^{\circ}C$. The specimens of x=2.14, 2.19, and 2.20 consisted of two phase: $UO_{2+x}$(Fm3m, a≒5.4$\AA$) and $U_4$$O_{9}$(I43d, a≒21.8$\AA$). The proportion of the $UO_{2+x}$(Fm3m) phase increased with increasing the temperature. The variation of the proportion of the two phases with temperature in the U $O_{2.2}$ and U $O_{2.18}$ samples showed some deviation from the expected values from the phase diagram especially at the high temperature range. The phase transitions ${\gamma}$longrightarrow$\beta$longrightarrow$\alpha$ of $U_4$$O_{9}$ were discussed in relation with the phase separation.eparation.ion.