• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.28-34
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• 2003

This study was performed to compare the effects of chaff and sawdust as bulking materials on temperature, pH, weight and volume reduction and salinity in aerobic composting of food wastes. Volume ratios of food wastes to chaff in reactor of Control, Ch-l, Ch-2, Ch-3 and Ch-4 were 4:0, 4:1, 4:2, 4:3 and 4:4, respectively. Volume ratios of food wastes to sawdust in reactor of Control, Sd-l, Sd-2, Sd-3 and Sd-4 were 4:0, 4:1, 4:2, 4:3 and 4:4, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours aeration per day. The lowering of the volume ratio of food wastes to chaff and sawdust resulted in the reaction at higher reaction temperature and the elongation of the high temperature reaction period. The lowering of the volume ratio of food wastes to chaff and sawdust resulted in faster pH increase. In the volume ratio of 4:3 and 4:4, pH increased faster in food-chaff mixtures than in food-sawdust mixtures. The lowering of the volume ratio of food wastes to chaff and sawdust resulted in faster steady state in the weight reduction rate and the volume reduction rate. The weight reduction rates of chaff mixtures were higher than those of sawdust mixtures, but the volume reduction rates of sawdust mixtures were more higher than those of chaff mixtures. Salinity increased as composting reaction proceeded, due to reduction in mass weight. The final salinity of Control was 2.79%, and the final range of salinities of chaff and sawdust mixtures were 2.18∼2.37% and 1.86∼2.05%, respectively.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.827-833
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• 2011

The objective of this study was to develop a fluorogenic real-time PCR-based assay for detecting and quantifying amounts of cow milk in cow/goat milk mixtures or goat milk products. In order to quantify the exact amount of cow milk in cow/goat raw milk mixtures and commercial goat milk products, it was necessary to achieve quantitative extraction of total genomic DNA from the raw milk matrix. Both mammalian-specific PCR and cow-specific PCR were performed. A cow-specific 252 bp band obtained from the raw cow milk and raw goat milk mixtures, commercial goat milk, and two goat milk powders was identified, along with the relationship between the cow milk amount and band intensity of the electrophoresis image. The detection threshold was found to be 0.1%. The expression of cow's 12S rRNA in the cow/goat milk mixtures, commercial goat milk, and two goat milk powders was identified. The expression quantity of the milk 12S rRNA increased with increasing ratios of the cow/goat milk mixtures. Using these calibrated relative expression levels as a standard curve in the cow/goat raw milk mixtures, the contents of cow milk were 1.8% in the commercial goat milk, 9.6% in goat milk powder A, and 11.6% in goat milk powder C. However, cow milk was not detected in goat milk powder B.

• Korean Membrane Journal
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• v.2 no.1
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• pp.36-47
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• 2000

This paper deals with the separation of MTBE-methanol mixtures using crosslinked Poly(vinyl alcohol)(PVA) membranes with sulfur-succinic acid(SSA) as a crosslinking agent by pervaporation and vapor permeation technique. The operating temperatures, methanol concentration in feed mixtures, and SSA concentrations in PVA membranes were varied to investigate the separation performance of PVA/SSA membranes and the optimum separation characteristics by pervaporation and vapor permeation. And also, for PVA/SSA membranes, the swelling measurements were carried out to study the transport phenomena. The swelling measurements were carried out for pure MTBE and methanol, and MTBE/methanol=90/10, 80/20 mixtures using PVA/SSA membranes with varying SSA compositions. There are two factors of the membrane network and the hydrogen bonding. In pervaporation separation was also carried out for MTBE/methanol=90/10, 80/20 mixtures at various temperatures. The sulfuric acid group in SSA took an important role in the membrane performance. The crosslinking effect might be over the hydrogen bonding effect due to the sulfuric acid group at 3 and 5% SSA membranes, and this two factors act vice versa on 7% SSA membrane. In this case, the 5% SSA membrane shows the highest separation factor of 2,095 with the flux of 12.79g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$ which this mixtures show near the azeotopic composition. Compared to pervaporation, vapor permeation showed less flux and similar separation factor. In this case, the flux decreased significantly because of compact structure and the effect of hydrogen bonding. In vapor permeation, density or concentration of methanol in vaporous feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membranes shows the highest separation factor of 2,187 with the flux of 4.84g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$.

• Membrane Journal
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• v.2 no.1
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• pp.36-36
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• 1992

This paper deals with the separation of MTBE-methanol mixtures using crosslinked Poly(vinyl alcohol)(PVA) membranes with sulfur-succinic acid(SSA) as a crosslinking agent by pervaporation and vapor permeation technique. The operating temperatures, methanol concentration in feed mixtures, and SSA concentrations in PVA membranes were varied to investigate the separation performance of PVA/SSA membranes and the optimum separation characteristics by pervaporation and vapor permeation. And also, for PVA/SSA membranes, the swelling measurements were carried out to study the transport phenomena. The swelling measurements were carried out for pure MTBE and methanol, and MTBE/methanol=90/10, 80/20 mixtures using PVA/SSA membranes with varying SSA compositions. There are two factors of the membrane network and the hydrogen bonding. In pervaporation separation was also carried out for MTBE/methanol=90/10, 80/20 mixtures at various temperatures. The sulfuric acid group in SSA took an important role in the membrane performance. The crosslinking effect might be over the hydrogen bonding effect due to the sulfuric acid group at 3 and 5% SSA membranes, and this two factors act vice versa on 7% SSA membrane. In this case, the 5% SSA membrane shows the highest separation factor of 2,095 with the flux of 12.79g/㎡·hr for MTBE/methanol=80/20 mixtures at 30℃ which this mixtures show near the azeotopic composition. Compared to pervaporation, vapor permeation showed less flux and similar separation factor. In this case, the flux decreased significantly because of compact structure and the effect of hydrogen bonding. In vapor permeation, density or concentration of methanol in vaporous feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membranes shows the highest separation factor of 2,187 with the flux of 4.84g/㎡·hr for MTBE/methanol=80/20 mixtures at 30℃.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.149-158
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• 2007

Evaluation of the asphalt mixture modified with crumb rubber modifier(CRM) was performed to estimate possibility of using it as a paying material. OACs(optimum asphalt content) of CRM modified asphalt mixtures by dry process and wet process were determined by Marshall mix design and Wheel tracking test and moisture susceptibility test by freezing and thawing were carried out with CRM modified asphalt mixtures at OACs. The results from these tests, resistance of permanent deformation of CRM modified asphalt mixtures were superior to one of AP-5 while showing very low resistance of moisture sensitivity by freezing and thawing. This means that CRM modified asphalt mixtures are very sensitive to freezing and thawing. However, CRM modified asphalt mixture with anti-stripping material showed high improvement to resistance of moisture susceptibility by freezing and thawing. Therefore, it is recommended that when CRM mixtures were used in domestic, CRM modified asphalt mixtures should be with prevention against freezing and thawing resistance by moisture susceptibility.

• International Journal of Highway Engineering
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• v.18 no.1
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• pp.57-62
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• 2016

PURPOSES : Reflection cracking has been one of the major causes of distress when asphalt pavement is laid on top of concrete pavement. This study evaluated the reflection cracking resistance of asphalt mixtures reinforced with asphalt embedded glass fiber and carbon fiber using a Texas Transportation Institute (TTI) overlay tester. METHODS : Different asphalt mixtures such as polymer-modified mastic asphalt (PSMA) and a dense graded asphalt mixture were reinforced with asphalt-embedded carbon fiber and glass fiber. For comparison purposes, two PSMA asphalt mixtures and one dense graded asphalt mixture were evaluated without fiber reinforcement. Two different overlay test modes, the repeated overlay test (R-OT) and monotonic overlay test (M-OT), were used to evaluate the reflection cracking resistance of asphalt mixtures at $0^{\circ}C$. In the R-OT test, the number of repeated load when the specimen failed was obtained. In the M-OT test, the tensile strength at the peak load and tensile strain were obtained. RESULTS : As expected, the fiber-reinforced asphalt mixture showed a higher reflection cracking resistance than the conventional nonreinforced asphalt mixtures based on the R-OT test and M-OT test. The dense graded asphalt mixture showed the least reflection cracking resistance and less resistance than the PSMA. CONCLUSIONS : The TTI overlay tester could be used to differentiate the reflection cracking resistance values of asphalt mixtures. Based on the R-OT and M-OT results, the carbon-fiber-reinforced asphalt mixture showed the highest reflection cracking resistance among the nonreinforced asphalt mixtures and glass-fiber-reinforced asphalt mixture.

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.735-741
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• 2017

This study was conducted to investigate if the supplement formula may improve alcohol metabolism in healthy adult men. In a double-blinded, randomized, crossover study, subjects were administrated yeast extract mixtures (YEM, n=15), Hovenia dulcis mixtures (HDM, n=15), placebo (PLA, n=15), and control (CON, n=15) in an oral dose followed by one week washout periods. At each visit (0, 1, 2, 3, 4 week), subjects drank 450 mL, 20.1 percent alcohol after administered mixtures. Blood was drawn periodically (0, 0.25, 0.5, 1, 2, 4, 6, 15 hours). Fifteen subjects completed the protocol and were included in the analysis. Plasma ethanol concentration was lower in YEM (10 percent) and the HDM (5 percent) groups. The area under the curves (AUC) and $C_{max}$ for plasma ethanol were significantly decreased only in the YEM group, when compared with the CON group. The AUC and $C_{max}$ for plasma acetaldehyde concentration were significantly decreased in the YEM (45 and 54 percent) and the HDM (35 and 53 percent) groups respectively, when compared with PLA (p<0.01). Together, these findings validate that YEM or HDM improved alcohol metabolism and hangover syndromes, leading to reduce alcohol concentration and acetaldehyde concentration without adverse effects.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.13-24
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• 2011

In the part of geotechnical engineering, soils are classified as either the coarse grained soil or the fine-grained soil following the fine content($F_c$=50%) according to the granularity, and appropriate design codes are used respectively to represent their mechanical behaviour. However, sand-clay mixtures, which are typically referred to as intermediate soils, cannot be easily categorized as either sand or clay. In this study, several monotonic undrained shear tests were carried out on Silica sand fine mixtures with various proportions, and a wide range of soil structures, ranging from one with sand dominating the soil structure to one with fines controlling the behaviour, were prepared using compaction method or pre-consoldation methods in prescribed energy. The shear strength of mixtures below the threshold fines content is observed that as the fines content increases, maximum deviator stress ratio decrease for dense samples while an increase is noted for loose samples. Then, by using the concept of fines content and granular void ratio, the monotonic shear strength of the mixtures was estimated. It was found that the shear behavior of mixtures is greatly dependent on the skeleton structure of sand particles.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.13-19
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• 2021

BACKGROUND: Chemicals such as antibiotics and surfactants can enter agricultural environment and they can be degraded by natural processes such as photolysis. These chemicals exist in mixtures in the environment, but studies on degradation of the mixtures are limited. This study compares the photodegradation of Triton X-100 (TX) and antibiotics [tetracycline (TC) and sulfathiazole (STH)] when they are in a single solution or in mixtures. METHODS AND RESULTS: TC, STH, and TX solutions were exposed to UV-A for the photodegradation tests for 14 days. The residual TC, STH, and TX concentrations were analyzed by using HPLC. The TC degradation was similar regardless of the presence of TX, while the TX degradation was lower in the presence of TC. The STH degradation was similar regardless of the presence of TX, while the TX degradation was greater in the presence of STH. However, the STH degradation was slower in the TC-STH-TX mixture than in the STH-TX mixture. Also, the TX degradation was negligible in the TC-STH-TX mixture. The results show that the photodegradation of TC, STH, and TX can be different in mixtures. This can be attributed to the different emission and absorption wavelengths of each compound and interaction between these compounds and photoproducts. CONCLUSION: Overall, this study emphasizes that photodegradation of single chemicals and chemical mixtures can be different, and more studies on single compounds as well as mixtures are required to understand the fate of chemicals in the environment in order to manage them properly.

• Journal of Mechanical Science and Technology
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• v.17 no.6
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• pp.935-944
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• 2003

Forced convective boiling heat transfer coefficients were predicted for an annular flow inside a horizontal tube for pure refrigerants and nonazeotropic binary refrigerant mixtures. The heat transfer coefficients were calculated based on the turbulent temperature profile in liquid film and vapor core considering the composition difference in vapor and liquid phases, and the nonlinearity in mixing rules for the calculation of mixture properties. The heat transfer coefficients of pure refrigerants were estimated within a standard deviation of 14% compared with available experimental data. For nonazeotropic binary refrigerant mixtures, prediction of the heat transfer coefficients was made with a standard deviation of 18%. The heat transfer coefficients of refrigerant mixtures were lower than linearly interpolated values calculated from the heat transfer coefficients of pure refrigerants. This degradation was represented by several factors such as the difference between the liquid and the overall compositions, the conductivity ratio and the viscosity ratio of both components in refrigerant mixtures. The temperature change due to the concentration gradient was a major factor for the heat transfer degradation and the mass flux itself at the interface had a minor effect.