• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1129-1135
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• 2005

In this study. the applicability of a rotating reactor for the oxidative removal of aqueous humic substances extracted from the Han River in Seoul, Korea was investigated. As air blowing for proper mixing of $TiO_2$ photocatalyst could inhibit UV-irradiation between a UV lamp and photocatalyst by air bubbles, a rotating reactor with some baffles was used for better UV-irradiation effect in this study. Han River humic substances are different from the other commercial humic substances(e.g., from Aldrich and International Humic Substance Society). Their characteristics were investigated with structural and spectroscopic analyses using FT-IR(Fourier transform-infrared), and $^{13}C$-NMR (nuclear magnetic resonance). The humic substances were extracted by XAD-7HP and treated with $TiO_2$-coated hollow beads under UV-A and UV-C irradiation in order to solve problems of separation and recovery of photocatalyst after reaction. At approximately 5 mg/L of initial TOC concentration, pH 3 and $2.0\;g-TiO_2/L$ dose, photocatalytic oxidation of Han River humic substances showed the optimum removal efficiency. Also, UV-C and UV-A lamps showed similar TOC removal efficiency. However, under UV-C irradiation, Han River humic substances were degraded to smaller compounds and increased the proportion of low molecular weight fractions compared to UV-A.

• The Korean Journal of Mycology
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• v.46 no.3
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• pp.325-331
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• 2018

We aimed to increase the utility of Broussonetia kazinoki (paper mulberry) by using its woody parts as a substrate for Lentinula edodes cultivation. Using different mixing ratios of paper mulberry and oak tree sawdust, five types of column-type media were prepared (1.2 kg each). Two L. edodes strains (NIFoS 2462 and NIFoS 2778) were used in this study. In the first flush, numerous small mushrooms were harvested because the fruited mushrooms were densely packed on the small media. The highest productivity was obtained with a 3:1 mixture of paper mulberry and oak tree sawdust (Q. acutissima:Q. mongolica, 1:1). In particular, for NIFoS 2462, the proportion of paper mulberry in the medium positively correlated with productivity. The size of NIFoS 2778 was uniform in all media tested. By contrast, the mushroom weight of NIFoS 2462 decreased, but the other characteristics were not significantly affected. Collectively, these findings suggest that B. kazinoki sawdust could be used to grow shiitake mushrooms and that some oak sawdust substitution is also possible. Our results could increase the utility of discarded by-products, such as sawdust.

• Food Science and Preservation
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• v.16 no.3
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• pp.311-316
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• 2009

Changes in physiochemical properties and polyphenol activities of wine fermented with apples and Rosa rugosa Thun were investigated. To this end, four different mixing ratios of apple and R. rugosa, including R. rugosa:apple 2:1 (Apple 33), R. rugosa:apple 1:2 (Apple 67), R. rugosa:apple 1:5 (Apple 83), and apple alone (Apple 100), were prepared and fermented by Saccharomyces bayanus for 14 days at $24^{\circ}C$ with a further 14 days of post-fermentation at $20^{\circ}C$. The final ethanol content ranged from 8.2.10.2%, with no significant difference between the four groups after fermentation and post-fermentation. Final Brix, pH, and total acidity of the four samples ranged from 7.1.7.5 Brix, pH 3.85.4.07, and acidity 0.73.1.19%. As the proportion of R. rugosa increased, the anthocyanin content and color intensity of wine also increased, whereas the free amino acid concentration decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.4
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• pp.239-246
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• 2008

This research tried to find out the optimum fabrication method of calcined clay granules comprising zeolite. Kaolin clay and natural zeolite powder were used as raw materials of calcined clay, and silica stone powder was used for controlling the porosity of the granules. The granulation was performed with two kinds of granulators: a pan granulator and a high-shear mixer granulator. Various granules were fabricated by the mixing ratios and the rotation speeds of the granulators, and were heated from 400 to $700^{\circ}C$ at $100^{\circ}C$ interval. The crushing strength, pore size distribution, and CEC of the granules were measured. The evaluation method for the resistance of granules to human treading was created and the tests were conducted at dry and wet conditions. The resistance and crushing strength improved in proportion to the rotation speed of the granulator and the heating temperature, but the CEC decreased. The pellet made by the pan granulator did not have the strength against treading upon heating to below $700^{\circ}C$, but the pellet made by the high-shear mixer granulator endured the treading test upon heating to over $500^{\circ}C$

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1719-1724
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• 2016

The objective of this study was to determine the effects of physically effective neutral detergent fiber (peNDF) content in total mixed ration (TMR) on dry matter intake, digestibility, and chewing activity in fattening Hanwoo (Bos taurus coreanae) heifers. The experiment was designed as a replicated $3{\times}3$ Latin square using 12 heifers. Fattening heifers were offered one of three diets [high (T1), medium (T2), and low (T3) peNDF] obtained by different mixing times (3, 10, and 25 min) for the same TMR feed. The peNDF content of TMR was determined by multiplying the proportion of dry matter retained by a 1.18 mm-screen in a Penn State Particle Separator by the dietary NDF content. The $peNDF_{1.18}$ content was 30.36%, 29.20%, and 27.50% for the T1, T2, and T3 diets, respectively (p<0.05). Dry matter intake was not affected by peNDF content in TMR. Total weight gain in T1 group was significantly higher (p<0.05) than in T2 and T3 groups. However, weight gain did not differ between T2 and T3 groups. The feed conversion ratio decreased with an increase in the peNDF content (T1: 12.18, T2: 14.17, and T3: 14.01 g/g). An increase in the peNDF content of TMR was associated with a linear increase in the digestibility of dry matter, crude protein, crude fiber, neutral detergent fiber, and acid detergent fiber (p<0.05). Also, an increase in peNDF content of the TMR resulted in a linear increase in the number of chews in eating and ruminating (p<0.05), and consequently in the number of total chews (p<0.05). These results indicate that peNDF content affects digestibility and chewing activity. Consequently, the peNDF content of TMR should be considered for improving feed efficiency, digestibility, body weight gain, and performance in fattening heifers.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.105-111
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• 1999

To investigate the relationships between ocean environmental characteristics and thechange of the catch, we analyzed various environmental factors such as mean temperature, salinity, current vectors, lunar day and wind vectors from 1995 to 1996 and the catch fluctuation of Hanlim set net from 1994 to 1996. The results are as follow ; 1) The proportion of fishes caught in Hanlim set net is highest for horse mackere1 ($69.2\%$) and is followed by common mackerel ($18.4\%$), hair tail ($5.6\%$), squid ($2.7\%$) and rabbit fish ($1.4\%$) in order. Two peaks in the monthly catch appeared in June and October in the operation period of May- December. 2) The flow direction was northward in flood time and southeastward in ebb time around the Hanlim set net. Thus, the vortical mixing of sea water was active and continued for more than 3 hours. In addition, mean daily temperature was low due to the presence of middle and bottom water in offshore. Increase in salinity or high salinity of sea water provides a favorable condition for catches of fishes. Catches in the first quarter and the last quarter of the moon were larger than that in full moon and the last of the month. In particular, when south or southeasterly wind velocity reaches about 3$\~$6.5 m/s, the possibility of catches increases.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.809-815
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• 1997

A series of experiments were conducted to study effects of osmolality and $Ca^{2+}$ on sperm motility in marbled sole, Limanda yokohamae. Spermatozoa were immotile when the milt was mixed with solutions (electrolyte or non-electrolyte) of lower osmolality than the average seminal plasma osmolality (351 mOsm/kg), but became motile after mixing milt with an hyperosmotic solution. However, with the osmolality above 1,639 mOsm/kg spermatozoa ceased their movement. When the milt was suspended in the $Ca^{2+}$ free artificial seawater (ASW) containing ethylenglycoltriamine (EGTA), the percentage of motile spermatozoa decreased in proportion to the increase of EGTA. Most spermatozoa were quiescent in a medium containing 3 mM EGTA. The motility of spermatozoa prevented by 3 mM EGTA was recovered by the subsequent addition of $Ca^{2+}$ over the concentration of 0.25 mM. Effects of calmodulin antagonist, trifluoperazin (TFP) on spermatozoa were examined to elucidate the possible functions of calmodulin in sperm motility. TFP immobilized spermatozoa 5n ASW at the concentration of 0.5 M. These findings suggest that calcium is an effective external factor in the initiation process of sperm motility.

• Applied Biological Chemistry
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• v.24 no.3
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• pp.200-205
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• 1981

Some chemical components, absorbance at 450nm and color of traditional and improved soysauce during fermentation were investigated. The traditional soysauce was made from soybean Meju and the improved soysauces were prepared from Kojis of various mixtures of soybean and wheat. The contents of reducing sugar were higher in the improved soysauces than in the traditional soysauce and it increased with proportion to the mixing amount of wheat. The contents of total nitrogen and amino nitrogen were increased gradually during fermentation and, in the improved soysauce, it increased with the amount of soybean. The changes of the absorbance and the chromaticity were greaser in the traditional soysauce than in the improved soysauce during fermentation. The increase of absorbance and the chromaticity was greater in the improved soysauce than that of the traditional soysauce during heating process. In the improved soysauce, the greater the amounts of wheat in Koji, the greater the increase of color.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.41-49
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• 2009

Cement concrete pavement has become more common in Korean highway systems. However, as its service period increases, there are some technical problems occurs and no clear solution is available primarily due to the lack of active researches. This research, hence, aims to develop a new mix proportion that may provide better strength and durability with extended service life. Based on a variety of literature reviews, the experimental variables were determined as unit cement content, S/a ratio and W/C ratio. From the experimental works, it is recommended to increase the unit cement content up to 375kg/$m^3$, 400kg/$m^3$ and 425kg/$m^3$. The target slump and air content were set 40mm and 5%, respectively. The maximum size of coarse aggregate was decided to be 25mm because of the easiness of supply in the field. The reduction of W/C ratio was necessarily required and decreased to 0.4 which was proven not to cause any mixing problem with the increased unit cement contents along with polycarbon-based high range water reducing agent. In addition, it was known that the S/a ratio could be reduced to 0.34. The lowered S/a might be possible because of the increased cement paste and hence increased cohesiveness and workability.

• Journal of Korea Water Resources Association
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• v.37 no.3
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• pp.219-231
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• 2004

The use of air diffuser system to ameliorate the reservoir by breaking stratification is now widespread. This study focuses on the hydrodynamic behavior of bubble plumes, which is the major mechanism of destratification and their combined effect of adjacent plumes on destratification efficiency. By introducing 2-phase Computational Fluid Dynamics(CFD) technique, we could suggest the optimal diffuser spacing having optimal destratification efficiency by simply analyzing the complex destratification procedures varying with the seasonal stratification intensity and bubble flow rate. Lab experiments were also carried out to verify CFD model in thermally stratified fresh water which quite differs from former researches using salts. This study showed that the mixing efficiency strongly depends on the spacing of neighboring plumes. When diffuser spacing is lower than 1.5 times the depth, the combined effect is stronger; as Plume Number(PN) is increased, the efficiency is strongly affected by spacing. If the distance is shorter than the depth of water, the efficiency increases linearly in proportion to PN. Otherwise, the efficiency increases non-linearly. These findings suggest that the combined effect should be more quantitatively taken into consideration for design and operation of air-diffuser destratification system, and recommend that the optimal destratification efficiency will be when plume number is 1000 and the spacing between neighboring diffusers is 1.5 times the depth.