• Asian-Australasian Journal of Animal Sciences
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• v.27 no.2
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• pp.237-246
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• 2014

Two experiments were conducted to evaluate the efficacy of feeding an Escherichia coli (E. coli) derived phytase to pigs fed P deficient, corn-soybean meal diets. In Exp. 1, one hundred and twenty crossbred piglets ($9.53{\pm}0.84$ kg) were allocated to one of five treatments which consisted of four low P diets (0.61% Ca, 0.46% total P and 0.24% non-phytate P) supplemented with 0, 500, 1,000, or 20,000 FTU/kg E. coli phytase as well as a positive control formulated to be adequate in all nutrients (0.77% Ca, 0.62% total P and 0.42% non-phytate P). The treatments were applied to six pens with four pigs per pen for 28 days. In Exp. 2, ten crossbred pigs ($19.66{\pm}1.16$ kg) fitted with ileal T-cannula were used in a nutrient balance study. The pigs were assigned to treatments similar to those used in Exp. 1 in a doubly replicated $5{\pm}4$ incomplete Latin square design (5 diets with 4 periods). Each period consisted of a 5-d adjustment period followed by a 3-d total collection of feces and urine and then a 2-d collection of ileal digesta. Supplementation with phytase linearly increased (p<0.05) weight gain, feed intake, feed efficiency, bone breaking strength and fat-free dry and ash bone weight. There were linear increases (p<0.01) in the apparent ileal digestibility (AID) of DM, GE, CP, Ca, total P, inositol hexaphosphate ($IP_6$) and some AA with increasing dose of E. coli phytase. Pigs fed 20,000 FTU/kg had a greater (p<0.05) AID of IP6 (80% vs 59% or 64%, respectively) than pigs fed diets with 500 or 1,000 FTU/kg phytase. There were linear increases (p<0.05) in the total tract digestibility of Ca, total P, Na, K, Mg, and Zn as well as in the retention of Mg and Zn with increased phytase dose. The retention and utilization of Cu, and the total tract digestibility of CP and Cu quadratic increased (p<0.05) with increased phytase dose. In conclusion, supplementation of 500 FTU of phytase/kg and above effectively hydrolyzed phytate in low-P corn-soybean diets for pigs. In addition, a super dose of phytase (20,000 FTU/kg) hydrolyzed most of the IP6 and consequently further improved mineral use, protein utilization and performance.

• Journal of the Korea Concrete Institute
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• v.23 no.5
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• pp.617-626
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• 2011

Seven post-tensioned lightweight concrete (LWC) beam specimens were tested under a symmetrical two-point top loading system. The parameters investigated were the amounts of mild longitudinal reinforcement and effective prestressing. The design compressive strength and dry density of the LWC tested were 30 MPa and 1,770 $kg/m^3$, respectively. Similar to post-tensioned normal weight concrete (NWC) beams, the crack propagation and stress increase of the unbonded tendons were significantly affected by the amounts of mild longitudinal reinforcement and effective prestressing. With the increase in the amounts of mild longitudinal reinforcement and effective prestressing, the serviceability and flexural capacity of the beams were enhanced whereas the stress increase in the unbonded tendons decreased. To control the crack width in post-tensioned LWC beams, a minimum amount of mild longitudinal reinforcement specified in ACI 318-08 provision is required. The flexural behavior of post-tensioned LWC beams and stress increase of the unbonded tendons could be rationally predicted by the proposed non-linear two-dimensional analysis. On the other hand, ACI 318-08 flexure provision was too conservative about the post-tensioned LWC beams.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.1006-1014
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• 1996

A series of catalysts, $NiO-ZrO_2/WO_3$, for ethylene dimerization were prepared by coprecipitation from a solution of nickel chloride - zirconium oxychloride mixture followed by dry impregnation with an aqueous solution of ammonium metatungstate and calcination in air. On the basis of the results obtained from x-ray diffraction and DSC, the addition of NiO and $WO_3$ to $ZrO_2$ shifted the transition of $ZrO_2$ from amorphous to a tetragonal phase toward higher temperatures due to the interaction between NiO(or $WO_3$) and $ZrO_2$. $NiO-ZrO_2$ without $WO_3$ was inactive for the ethylene dimerization, but $NiO-ZrO_2/WO_3$ was found to be very active even at room temperature. The high catalytic activity of $NiO-ZrO_2/WO_3$ was closely correlated with the increase of acid strength by the inductive effect of $WO_3$.

• Analytical Science and Technology
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• v.25 no.6
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• pp.476-482
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• 2012

Asian dust particles are known to have sizes ranging from a few nanometers up to about a few micrometers. The environmental and health effects depend on the size of the dust particles. The smaller, the farther they are transported, and the deeper they penetrate into the human respiratory system. Sedimentation field-flow fractionation (SdFFF) provides separation of nano to microparticles using a combination of centrifugal force and parabolic laminar flow in a channel. In this study, the steric mode of SdFFF (Sd/StFFF) was tested for size-based separation and characterization of Asian dust particles. Various SdFFF experimental parameters including flow rate, stop-flow time and field strength of the centrifugal field were optimized for the size analysis of Asian dust. The Sd/StFFF calibration curve showed a good linearity with $R^2$ value of 0.9983, and results showed an excellent capability of Sd/StFFF for a size-based separation of micron-sized particles.The optical microscopy (OM) was also used to study the size and the shape of the dust particles. The size distributions of the samples collected during a thick dust period were shifted towards larger sizes than those of the samples collected during thin dust periods. It was also observed that size distribution of the sample collected during dry period shifts further towards larger sizes than that of the samples collected during raining period, suggesting the sizes of the dust particle decrease during raining periods as the components adsorbed on the surface of the dust particles were removed by the rain water. Results show Sd/StFFFis a useful tool for size characterization of environmental particles such as the Asian dust.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.113-120
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• 1985

A filed experiment was carried out to investigate the effects for growth, yield of red lopper (Saelona) and properties of soil by beer sewage sludge application to the sandy loam which fertility was common. The results obtained were summerized as follows. 1. Growth of red pepper in sludge plot was very poor by drought in early stage, but color of loaves was green and growth strength was better than nontreated plot after rainfall in last stage. There were no significant differencies between plant height, number of branch on main stem and stem height in sludge and standard plot. 2. Yield of matured red pepper per plant in NPK+, and PK+ sludge 1200kg, 2400kg and 4800kg/10a plot were less than those in standard plot respectively. 3. Ratio of dry weight of matured red pepper in NPK+, and PK+ sludge 1200kg, 2400kg and 4800kg/10a were high than those in standard plot appreciably. 4. Sewage sludge application (1200kg/10a. N=51kg) was available as nitrogen source of organic fertilizer considerably, but there were some growth inhibition by excess of amount applied. 5. Sewage sludge application decreased the pH of the soil and increased the content of organic matter and exchangeable babe in the soil appreciably.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.1971-1978
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• 2009

This study investigated the adsorption of safflower yellow dye on wool protein fiber and the optimum dyeing conditions to test color reproducibility. In addition, the effects of mordants on dye adsorption, color, fastness, and photofading rate were also studied. The prepared dye in powder form was characterized with UV-vis spectroscopy and FT-IR spectrometric analysis. The color of dyed fabrics was characterized by CIE $L^*a^*b^*$ coordinates, H V/C, and K/S values. The color reproducibility of the dyed wool fabrics was examined. The amount of dye adsorption increased and also, the shade of the dyed wool fabrics became deeper and more saturated with increasing temperature, time, and dye concentration. The maximum color strength was obtained at pH 3.0. The shade of dyed wool fabrics ranged from light yellow to dark mustard yellow as the pH of the dye bath shifted from alkaline to acidic. Color reproducibility was reliable with color differences in the range of 0.53~1.75. Fastness to dry cleaning was relatively good at 4/5 rating irrespective of mordanting. Fe and Cu mordants showed the least color change of the dyed wool fabrics after exposure to light. Mordants did not contribute to improve dye uptake and color fastness, although they made variations in color tone. Safflower yellow dye can be used satisfactorily without mordants and will not cause damage to the environment.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.867-873
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• 2010

This study investigated the corrosion properties of reinforced concrete with the addition of steel fibers. The transport properties of steel fiber-reinforced concrete such as permeable void, absorption by capillary action, water permeability and chloride diffusion were first measured to evaluate the relationship with the corrosion of steel rebar. Test results showed a slight increase on the compressive strength with the addition of steel fibers as well as considerable improvement of penetration resistance to mass transport of harmful materials into concrete. The addition of steel fibers in reinforced concrete accelerated the initiation of steel corrosion contrary to the expected results based on the measured transport properties. The NaCl ponding surface showed the spalling failure due to the corrosion expansion of steel fibers and the cut-surface around the steel rebar showed the localized steel fiber's corrosion. The wet-dry cycling with high chloride ions as well as high temperature seems to induce the increase of salt crystallization on the pores continually and the increased pressure with the steel fiber's corrosion on the pores caused the spalling failure on the exposed surface. The microcracking on the surface therefore accelerated the movement of water, chloride ions and oxygen into the embedded steel rebar. The mechanism affecting corrosion of embedded steel reinforcement with steel fibers in this study are not yet fully understood and require further study comprising of accurate experimental design to isolate the effect of steel fiber's potential mechanism on the corrosion process.

• Journal of the Korea Concrete Institute
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• v.20 no.3
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• pp.271-282
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• 2008

Specific joint devices composed of end-plates and through bolts are under development to assemble steel beams to PC columns efficiently by dry construction method for the PCS structural system, of which major structural components are precast concrete columns and steel beams. Seismic performance of the joint devices had been evaluated by experimental tests in the previous studies and it was showed that all the performance requirements regarding to strength deterioration, stiffness degradation and energy dissipation capacity were satisfied to the criteria of ACI requirements, but the initial stiffness was not. In order to find out possible causes of the insufficient rigidity of the joint devices and provide the proper measures to improve the performance of the joint accordingly, numerical analyses were carried out by using ABAQUS. Parameters, such as thickness of neoprene pad, conditions of surface between PC column and end-plate, magnitude of pretension forces of through bolts, stiffness of end-plate were taken into consideration. As the result, it was found that the rigidity of the PCS system was negatively affected by the magnitude of initial gaps between PC columns and end-plates, and insufficient stiffness of neoprene fillers and end plates. In order to improve the initial stiffness performance of the joints, measures such as increase of the magnitude of pretension forces on through bolts and increase of the stiffness of end-plate by reducing the bolt pitch and providing adequate stiffeners are recommended.

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.277-291
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• 1983

In order to investigate the shear characteristics of earth structure after construction. Four sample soils with different gradation were selected and compacted under the optimum moisture content and the maximum dry density. And the direct shear test and the triaxial compression test were performed with those sample soils under various pre-compression loads. The results were summarized as follows; 1. With the increase of the percent passing of No. 200 sieve, the cohesion of soil increased regularly and the internal friction angle of soil decreased with slow ratio. 2. The pre-compression increased the shear strength of compacted cohesive soil. The increase of cohesion was very apparent but the internal friction angle didn't show such regular tendency. 3. With the increase of pre-compression load, the slope of stress-strain curve showed steep at the early stage of horizontal strain. The vertical strain was small at the compression stage and big at the expansion stage. 4. When the vertical stress of shear test with increase in the horizontal strain was small, stress ratio(shear stress vs. vertical stress) of sample showed the largest value and the slope of stress ratio curve showed also steep. 5. When the sample was had the same condition, the cohesion of soil showed bigger value in the triaxial compression test and the internal friction angle of soil showed bigger value in the direct shear test.

• The Journal of Engineering Geology
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• v.10 no.1
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• pp.1-12
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• 2000

Heaving of road and subsidence of slope took place at the Wiri region of the local highway 999 in Gyeongsangbukdo, Korea after heavy rain in the next year of construction. Although the state government had performed remedial treatments by reducing the angle and the height of the slope, deformation had never stopped. Therefore, we have preformed the analysis of deformation and stabilityof the slope. Study area consists of the Cretaceous shale, siltstone and sandstone and two faults are found. The major deformation occurred by sliding of rock mass along faults after heavy rain because not only thepore pressure at the fault plane and the unit weight of sliding mass increased, but did the shearstrength of saturated fault clay become very low. The decrease in shear strength of saturated fault clayis the major factor among the reasons for deformation. Numerical simulations using limit equilibriummodel, finite difference model and finite element model were performed for eight cross sections.Although safety factors are above 1.7 during the dry season, they become below 1.0 when groundwaterlevel raises to surface. The maximum displacement is about 15-3Ocm. However, safety factors increasedto above 2.4 and the maximum displacement is below 2.08cm after remedial treatment, Indicating thatthe slope becomes stable.