• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.3
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• pp.218-225
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• 1990

Studies on the performance of a heat pump using non-azeotropic refrigerant mixtures are done. In order to estimate the thermodynamic properties for the selected non-azeotropic refrigerant mixtures including R22/R152a, R22/R142b, R22/R114 and R13B1/R152a, Peng-Robinson equation of state is adopted. The pressure-enthalpy diagram and the temperature-entropy diagram are plotted for each refrigerant mixture. Considerations on the capacity modulation for the heat pump system using refrigerant mixtures are taken into. Results show that when the heating load varies, the possibility for the capacity modulation is found in the heat pump system using a compressor with constant volume flow rate. Under a constant heating capacity condition in the heat pump system, the coefficient of performance increases when the refrigerant mixtures are used. The volume flow rate decreases as the mass fraction of lower boiler increases in this case.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.132-144
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• 2001

Iln order to figure out criteria of bentonite for using as impervious material of waste landfill, laboratory experiments were performed to reveal the geotechnical properties of soil-bentonite mixtures such as compaction test, direct shear test, unconfined compression test, triaxial compression test, consolidation test and permeability test. The results of the study are summarized as follows ; 1. Based on the compaction test, optimum moisture content increased with the increase of bentonite content, but maximum dry density decreased. 2. In unconfined compression test, the maximum strength of the soil-bentonite mixtures appeared at 10% bentonite content. The correlation equation between stress($\sigma$) and strain($\varepsilon$) of the soil-bentonite mixtures is given by ; $\sigma=\frac{a\cdot\varepsilon}{\varepsilon^n+b}$ 3. In shear test of the mixtures. the shear strength showed an increasing trend with increase of bentonite content and the maximum shear strength appeared at 10% bentonite content. 4. In consolidation test, the coefficient of compressibility $(a_v)$$(m_v)$$(C_v)$

• Proceedings of the Membrane Society of Korea Conference
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• 1996.03a
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• pp.69-90
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• 1996

In the chemical industry, in the pharmaceutical industry, and in a number of other industries separation processes are necessary to separate and purify products and raw materials [1,2]. Separation processes are also widely used in other applications such as in recycling valuable materials from waste streams. Unit operations for separation processes can be classified in phase separation techniques and component separation techniques based on the nature of the feed mixtures to be separated. The former techniques are used for the separation of heterogeneous mixtures, in which the feed is already present in two or more separated phases on a micro-scale. The latter are suitable for the separation of homogeneous mixtures such as gaseous mixtures and mixtures of completely miscible liquids. tn these cases the separation into individual components is generally achieved by utilizing the differences in physico-chemical properties of components, and is much more difficult compared to phase separation techniques. Separation processes such as distillation, evaporation, liquid-liquid extraction, and crystallization belong to this class.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.395-402
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• 2014

The current study was conducted to identify technology for the production of high quality pork, based on the meat consumption habits of consumers. Macsumsuk, a type of kaolinite (a clay mineral), and/or a mixture of herbs (Mori Folium, Sophorae Radix, Glycyrrhizae Radix, Citri Leiocarpae Exocarpium, and Pogostemi Herba) were added to the diets of fattening pigs. Sixty barrow pigs (4 kinds of treatment ${\times}5$ pigs/treatment ${\times}3$ replicates) were randomly assigned to either the Control (no additives), T1 (3% Macsumsuk), T2 (3% Herb mixtures), or T3 (3% Macsumsuk + 3% Herb mixtures) groups, and were fed the diets for 60 d. Dressed weights were in the order of T1 ($93.40{\pm}4.68kg$) > T2 ($91.40{\pm}6.52kg$) > Control ($88.80{\pm}1.57kg$) > T3 ($86.80{\pm}2.01kg$). Back-fat thickness of the Control animals ($23.2{\pm}1.03mm$) was significantly greater than that of the various treatment groups (p<0.01). Numeric values representing the carcass yield and quality grade were higher for all the treated groups than the Control group, thought the difference was not statistically significant. Crude fat content was significantly higher in the Control group ($2.23{\pm}0.34%$) than in the treated groups (p<0.05). The addition of both Macsumsuk and herb mixtures into the diets of the pigs significantly reduced cooking loss of the pork compared to the Control (p<0.05). No statistically significant changes were observed in the shear force (average $5.87{\pm}0.54kg/cm^2$), water holding capacity (average $54.59{\pm}3.16%$), or CIE values of the pork, whereas cholesterol levels significantly decreased (p<0.01) in those fed Macsumsuk and/or the herb mixtures. No significant changes in fatty acid composition, total saturated fatty acid (SFA), total unsaturated fatty acid (UFA), or UFA/SFA ratios were observed by any of the treatments. In conclusion, the results obtained from this study suggest that the addition of Macsumsuk and/or herb mixtures into the diets of growing and fattening pigs improves the pork quality by reducing cooking loss, decreasing cholesterol content, and enhancing sensory characteristics.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.66-70
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• 1990

Correlations have been developed for estimating the viscosities of ternary mixtures of sucrose-sodium chloride-water over a temperature range of $10-40^{\circ}C$ and a concentration range of 1.0064-5.7037 molality sodium chloride and 0.3436-2.5966 molality sucrose. The viscosity data of sodium chloride and sucrose solutions have been fitted very well utilizing proposed polynomial equation, respectively and the temperature dependence analysis for sodium chloride and sucrose solutions showed that 1/T dependence is accurate. The experimental viscosity data for surose-sodium chloride-water mixtures were fitted to a five parameter polynomial with a goodness of fit approximating experimental error and it seems that there is no significant Interaction between sodium chloride and surose solutions.

• Korean journal of food and cookery science
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• v.10 no.2
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• pp.161-165
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• 1994

It was aimed to investigate the effects of caffeic acid on the rates of Maillard reaction. The rates of browning reaction increased as the browning temperature increased. The color intensity of the browning mixtures indicated to depend on the amino acid rather than reducing sugar. Also, the color intensity of the browning mixtures increased more rapidly in the presence of caffeic acid. The increase in color intensity seemed to depend mainly to the polymerization of o-quinones formed from caffeic acid. The caffeic acid, furthermore, appeared to enhance the color intensity of the browning mixtures through the interaction with amino acid, especially methionine and phenylalanine. The activation ener-gies of the browning reaction without caffeic acid were 108∼130 J/mol, and Q10 values were 2.6∼3.2. The activation energies and Q10 values of browning mixtures decreased in the presence of CA. The activation energies of the browning mixtures with caffeic acid were 90∼101J/mol, and Q$\_$10/ values were 2.0∼2.6.

• Journal of the Korean Society of Safety
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• v.36 no.3
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• pp.1-6
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• 2021

Hydrogen is considered a cleaner energy source than fossil fuels. As a result, the use of hydrogen in daily life and economic industries is expected to increase. However, the use of hydrogen energy is currently limited because of safety issues. The rate of combustion of the hydrogen mixture is about seven times higher than that of hydrocarbon fuels. The hydrogen mixture is highly flammable and has a low minimum ignition energy. Therefore, it presents considerable risks for fire and explosions in all areas of hydrogen manufacturing, transportation, storage, and use. In this study, the auto-ignition characteristics of hydrogen were investigated numerically for diluted hydrogen mixtures. Auto-ignition temperature, a critical property predicting the fire and explosion risk in hydrogen combustion, was determined in well-stirred reactors. When N₂ and CO₂ were used to dilute the hydrogen/air mixture, the ignition delay time increased with increasing dilution ratios in both cases. The CO₂-diluted mixtures exhibited a longer ignition delay than the N₂-diluted mixtures. We also confirmed that lower initial ignition temperatures increased the ignition delay times at 950 K and above. Overall, the auto-ignition characteristics, such as the concentrations of participating species and ignition delay times, were primarily affected by the initial temperature of the mixture.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.21-30
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• 2015

PURPOSES : The purpose of this study was to evaluate the performance of rapid-setting polymer-modified asphalt mixtures with a high reclaimed asphalt pavement (RAP) content. METHODS: A literature review revealed that emulsified asphalt is actively used for cold-recycled pavement. First, two types of rapid-setting polymer-modified asphalt emulsion were prepared for application to high-RAP material with no virgin material content. The quick-setting polymer-modified asphalt mixtures using two types of rapid-setting polymer-modified asphalt emulsion were subjected to the following tests: 1) Marshall stability test, 2) water immersion stability test and 3) indirect tensile strength ratio test. RESULTS AND CONCLUSIONS : Additional re-calibration of the RAP was needed for laboratory verification because the results of analyzing RAP aggregates, which were collected from different job sites, did not deviate from the normal range. The Marshall stability of each type of binder under dry conditions was good. However, the Type B mixtures with bio-additives performed better in the water immersion stability test. Moreover, the overall results of the indirect tensile strength test of RAP mixtures with Type B emulsions exceeded 0.7. Further research, consisting of lab testing and on-site application, will be performed to verify the possibility of using RAP for minimizing the closing of roadways.

• Journal of Physiology & Pathology in Korean Medicine
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• v.34 no.2
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• pp.75-80
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• 2020

In this study, we investigated the dose-dependent effects of mixtures of Atractylodes macrocephala (AM) and Amomum villosum (AV) water extracts in a ratio of 3:1 on high fat diet (HFD)-induced obesity model. Oral administration of various concentrations with mixtures of AM and AV extracts in a ratio of 3:1 for 6 weeks inhibited HFD-induced increases of body, liver and epididymal fat weights in a dose-dependent fashions. Those effects may be mediated by decreased expressions of lipogenesis-related genes such as acetyl coA carboxylase (ACC) and fatty acid synthase (FAS) in liver. Also, increase of insulin and decrease of adiponectin in serum by HFD supply were inhibited by three different dosages of mixtures of AM and AV extracts in a ratio of 3:1. HFD supply induced increases of serum total cholesterol, triglyceride and LDL cholesterol. However, hyperlipidemia was significantly decreased in dose-dependent manners by treatment with mixtures of AM and AV extracts. Based on the results of the present study, hypolipidemic and anti-obesity effects by mixtures of AM and AV extracts were found in HFD-induced obesity model. Further clinical investigation is needed to develop anti-obesity therapeutic or preventive agents by using mixtures of AM and AV extracts.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.111-120
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• 2010

This study evaluated strength properties of recycled asphalt concretes using warm-mix technology. Granite with maximum size of 13mm and penetration grade of 80-100 virgin binder were used for mixing in recycled mixtures. Mix design was performed using 20% and 30% RAP(coarse : fine= 6 : 4) contents. GPC, penetration, absolute viscosity and kinematic viscosity were measured for determining ratio of two warm-mix additives (Evotherm and Sasobit). Low-density polyethylene(LD) used as asphalt modifier for improving stiffness of recycled WMA mixtures in this study. Therefore, a total of 11 mixtures were prepared in this study; 8 warm-mix recycled mixtures(2 RAP contents${\times}$2 warm-mix additives${\times}$2 modifiers), 2 hot-mix recycled mixtures and 1 HMA virgin mixture(control). Deformation strength, indirect tensile strength, moisture sensitivity, permanent deformation by wheel tracking tests were measured out for evaluating fundamental properties of recycled asphalt concretes using warm-mix technology.