• Journal of the Korean Society of Industry Convergence
• /
• v.12 no.3
• /
• pp.137-142
• /
• 2009

Burning velocity of methane-air mixtures with water vapor have been measured to study the process of flame propagation using schlieren photographs and computation. The computations were carried out for the burning velocity using premix code of Chemkin program to compare the experimental results. The quantity of water vapor contained were changed 5% and 10% of total mixtures, and equivalence ratio of mixtures between 0.8 and 1.2 were tested under the ambient temperature 323K and 373K. The results showed little difference between these two methods, the burning velocity was decreased by increasing the water vapor contents due to the interruption of flame development. And, the effect of ambient temperature was less significant by increasing the water contents on the burning velocity.

• International Journal of Contents
• /
• v.14 no.4
• /
• pp.57-64
• /
• 2018

Among many UNESCO world heritage sites in Korea, "Historic Village: Hahoe" is adjacent to Nakdong River and it is imperative to monitor the water level near the village in a bid to forecast floods and prevent disasters resulting from floods.. In this paper, we propose a recurrent neural network with multiple hidden layers to predict the water level near the village. For training purposes on the proposed model, we adopt the sixth-order error function to improve learning for rare events as well as to prevent overspecialization to abundant events. Multiple hidden layers with recurrent and crosstalk links are helpful in acquiring the time dynamics of the relationship between rainfalls and water levels. In addition, we chose hidden nodes with linear rectifier activation functions for training on multiple hidden layers. Through simulations, we verified that the proposed model precisely predicts the water level with high peaks during the rainy season and attains better performance than the conventional multi-layer perceptron.

• The Korea Journal of Herbology
• /
• v.32 no.3
• /
• pp.29-36
• /
• 2017

Objectives : In order to investigate the possibility of Sorbus commixta Heal. stem (SC) as a natural material, antioxidant activities of the hot water and ethanol extracts were examined. Methods : The samples of SC were pulverized, and fractions were extracted repeatedly three times from hot water and 70% ethanol at room temperature for 2 hours. The antioxidant activities were analyzed from total polyphenol, flavonoid contents, DPPH, ABTS, hydroxyl radical, $Fe2^+$ chelating, and nitrite scavenging activity. Results : Total polyphenol contents were significantly higher in ethanol extract group ($504.39{\mu}g/m{\ell}$) than in hot water extract group ($364.64{\mu}g/m{\ell}$). Total flavonoid contents were also significantly higher in ethanol extract group ($160.09{\mu}g/m{\ell}$) than in hot water extract group ($124.59{\mu}g/m{\ell}$). DPPH, ABTS, $Fe2^+$ chelating were slightly higher in ethanol extract gorups than in hot water extract groups, and increased in a dose-dependent manner. The hydroxyl radical scavenging activity (18.42~23.61%) of ethanol extract groups were shown to be approximately twice higher than that (7.63~10.37%) of hot water extract groups at $12.5{\sim}50{\mu}g/m{\ell}$ concentration. Nitrite scavenging activities of both ethanol and hot-water extract groups were shown to be higher in a dose dependent manner at the concentration of $12.5{\sim}50{\mu}g/m{\ell}$ at pH 3.0 than at pH 1.2, and ethanol extract groups (86.55~96.64%) had higher activity than the hot water extract groups (42.59~92.63%), which was higher than that of the control group antioxidant BHT (72.96~80.11%). Conclusions : The extracts of SC displayed antioxidant activities which suggested a natural material can be developed to functional material.

• Journal of the Korean Home Economics Association
• /
• v.18 no.2
• /
• pp.15-21
• /
• 1980

Three kinds of soybean curd were prepared with three coagulants such as calcium chloride, magnesium chloride and glucono delta lactone. The mineral contents of the three soybean curds were analyzed before soaking and after various lengths of soaking(1/2 hour, 1 hour, 2 hours, and 2 hours(water changed after 1/2 hour)). Results therefrom were as follows: 1. Before the three soybean cured were soaked, their moisture contents were 79-83g/%. The ash contents were 5.04g% in the soybean curd made with CaCl_{2}4.42g/% in the soybean curd prepared with MgCl_{2} and 3.86g/% in the soybean curd coagulated by glucono delta lactone. an analysis of calcium, magnesium and phosphorous contents showed that each element had a greater concentration in the soybean curds made with divalent mineral salts than in the soybean curd made with acid. 2. Changes taking place in the mineral contents of the soybean curds according to different soaking times were examined. The mineral contents tended to decease in process of soaking time. The soybean curds showed the highest rate of mineral dissolution after one hour of soaking, and then they tended to reabsorb minerals. When the soybean curds were soaked I freshly changed water for one hour and 30 minutes, their mineral contents indicated a greater diminishing trend but no significant difference was noticed among the different kinds of soybean curd. In case coagulant has been used excessively, it is necessary to soak the bean curds for about one hour to get the coagulant dissolved.

• Korean Journal of Plant Resources
• /
• v.35 no.6
• /
• pp.762-769
• /
• 2022

Growth characters and ingredient contents of two-year-old bellflower (Platycodon grandiflorum) roots were investigated under both control and soil moisture treatment condition using soil moisture control system including soil sensing and automatic water supply chain in this study. Root diameter, fine root number, root length, fresh weight and dry weight of the plant were significantly influenced by the automatic water treatment, 20%, 30%, 40% and 50%, respectively. Ingredient contents of the two-year-old roots in bellflower plants were detected in the 20% and 50% of controlled soil moisture content. Contents of amino acids were decreased by the soil moisture treatment, meanwhile, contents of minerals were not showed significant decrease except for phosphorus content. Showing no difference in proline and tyrosine, fourteen of the amino acid contents were gradually decreased by the increased soil moisture contents, with significant decrease in serine, glycine, alanine, leucine, lysine and histidine at 20% treatment.

• Journal of Environmental Science International
• /
• v.4 no.5
• /
• pp.427-435
• /
• 1995

In order to discuss the differences among the SMP(Surface Moisture Availability Parameter), by previous researchers on the basis of their own theoretical and empirical background, we assessed the SMP according to the soil types and volumetric soil water contents. The results are as follows. There are differences among all the five SMAPs. There's a tendency that the larger grain size, the higher value of parameters. And they divided into two groups for their value: one group has parameters with exponential function and the other with cosine and linear function. The maximum difference between the two groups appears when the volumetric soil water contents are 0.07m3m-3 for sand, 0.l1m3m-3 for loam, 0.12 for clay, and 0.13m3m-3 for silt loam. So, these differences must be considered when we estimate the surface evaporation rate. From field data, the paddy field soil around Junam reservoir is classified as a silt has high wetness, 0.56. So, the parameter obtained from the field measurement is much higher than that of Clapp and Hornberger(1978)'s Table. This study treated the SMP for a certain point of time in winter season. But if we measured the soil water contents continuously, we could obtain better time-dependent parameter. Key words : SMAP(Surface Moisture Availability Parameter), Paddy field, Volumetric soil water content, Evaporation, Capillary potential.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.03a
• /
• pp.255-264
• /
• 2009

Soils containing vanishing materials lead changes in the microstructure of particulate media due to water inflow. Thus, dissolution renders some local unstability. As the moisture contents decease, the component of the vanished materials may affects on the cementation of paniculate materials. This cementation phenomenon has a huge influence on the stiffness, strength and stability under lower stress level. The goal of this study is to introduce the cementation effects on a compressional wave velocity, a shear wave velocity, and the resonant frequency of shear waves. The glass bead and salt water with different mole contents are used. Test results show that the changes of shear and compressional wave velocities consist of three stages. In the first region, compressional wave velocities increase and shear wave velocities decrease with a decreases in reducing water contents from 100% to 90~95%. In the second region, shear and compressional wave velocities become stable at 90~95% to 10% of the water contents. In the third region, shear and compressional wave velocities increases dramatically with a decrease in the water content due to the capillary force and cementation of salt. Furthermore, the resonant frequency of the shear waves shows similar phenomenon. Specimens prepared by glass beads and salt water are proved to be able to provide a meaningful insight in under structural behaviors of the cementation.

• Journal of the Korean Society of Food Culture
• /
• v.19 no.5
• /
• pp.484-490
• /
• 2004

The present study was conducted to investigate extraction characteristics and antioxidative activity of Schiznadra chinensis extracts. Schiznadra chinensis was extracted by reflux extraction(RE) under different extraction conditions including solvent. The solid yield, turbidity, color value, titratable acidity, free sugar contents, electron donating ability(EDA) and superoxide dismutase(SOD)-like ability of Schiznadra chinensis extracts were determined. The highest solid yield value was obtained with water of 10 fold. No significant difference in turbidity and color value were found among the extracts prepared with various extraction solvents, 75% ethanol, 50% ethanol and water. The highest titratable acidity was obtained with water extracts of Schiznadra chinensis. The free sugar contents of Schiznadra chinensis extracted with water showed the highest value. Schiznadra chinensis extracts with water included higher contents of free sugar compared with those of the other solvent extracts,50% ethanol and 75% ethanol extracts. The total polyphenol compound content of Schiznadra chinensis extracted with 50% ethanol showed the highest value. Schiznadra chinensis extracts with 50% ethanol included higher contents of total polyphenol compound compared with those of the other solvent extracts, water and 75% ethanol extracts. The electron donating ability of extracts were 60.87% in water, 57.24% in 50% ethanol, and 55.61% in 75% ethanol.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.7
• /
• pp.1014-1019
• /
• 2012

This study was conducted to evaluate the heavy metal contents of mudflat solar salt, salt water, and sea water produced in the nationwide salt pan. In mudflat solar salt, moisture contents were significantly different (p<0.001) between regions, ranging from 7.357% to 14.862%. Arsenic (As) content ranged from 0.007 ppm to 0.497 ppm, cadmium (Cd) from 0.000 ppm to 0.101 ppm, plumbum (Pb) from 0.000 ppm to 0.191 ppm, hydrargyrum (Hg) from 0.006 ppb to 0.180 ppb, and copper (Cu) from 0.039 ppm to 4.794 ppm between regions, which were significantly different (p<0.001). Further, As, Cd, Pb, and Hg contents of sea and salt water were not in excess of their criterion points. Our results suggest that heavy metal contents of mudflat solar salt, salt water, and sea water produced in the nationwide salt pan were at safe levels. However, continuous management of heavy metal contamination, such as PVC met, is still necessary.

• Journal of the Korean Society of Food Culture
• /
• v.5 no.2
• /
• pp.265-268
• /
• 1990

The effect of water extract in fruits of Omija (Schizandra chinensis Baillon) on alloxan-induced diabetic rats were determining the contents of metabolites and enzyme activities in the liver and serum of rat. The treatment with water extract in fruits of Omija showed increased in contents of protein, glycogen, and activity of glucose-6-phosphate dehydrogenase and a decreased in pyruvate content in the hepatic tissue from the alloxan treated group. These treatments were decreased contents of glucose, urea nitrogen, free fatty acid and activities of GPT, GOT, LDH.