• Asian-Australasian Journal of Animal Sciences
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• v.23 no.2
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• pp.263-271
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• 2010

This trial was conducted to determine the effects of feeding a diet containing solid-state fermented rapeseed meal on performance, nutrient digestibility, intestinal ecology and intestinal morphology of broiler chickens. A mixed liquid culture, containing approximately 5 log cfu/ml Lactobacillus fermentum, Enterococcus faecium, Saccharomyces cerevisae and Bacillus subtilis was prepared in a 1:1:1:1 ratio. A basal substrate (BS) containing 75% rapeseed, 24% wheat bran and 1% brown sugar was mixed with the liquid culture in a ratio of 10:3. Over the 30-day fermentation, isothiocyanates were reduced from 119.6 to 14.7 mmol/kg. A total of 168, day-old male Arbor Acres broiler chicks were assigned to one of three dietary treatments including a corn-soybean meal based control diet as well as two experimental diets in which the control diet was supplemented with 10% of the BS containing unfermented rapeseed meal or 10% of the BS containing rapeseed meal subjected to solid state fermentation. There were 8 pens per treatment and 7 birds per pen. From days 19-21 and days 40-42, uncontaminated excreta were collected from each pen for digestibility determinations. In addition, digesta from the colon and ceca were collected to determine the number of lactobacilli, enterobacteria and total aerobes. The middle sections of the duodenum, jejunum, and ileum were collected for intestinal morphology. Over the entire experimental period (d 1-42), the weight gain and feed conversion of birds fed fermented rapeseed meal were superior (p<0.05) to that of birds fed nonfermented rapeseed meal and did not differ from the soybean control. On day 42, birds fed fermented rapeseed meal had higher (p<0.05) total tract apparent digestibility coefficients for dry matter, energy, and calcium than birds fed non-fermented rapeseed meal. Colon and ceca digesta from broilers fed the fermented feed had higher (p<0.05) lactobacilli counts than birds fed the control and non-fermented rapeseed meal diets on day 21 and 42. Fermentation also improved (p<0.05) villus height and the villus height:crypt depth ratio in the ileum and jejunum on day 21 and 42. The results indicate that solid-state fermentation of rapeseed meal enhanced performance and improved the intestinal morphology of broilers and may allow greater quantities of rapeseed meal to be fed to broilers potentially reducing the cost of broiler production.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.167-178
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• 2000

An experimental study on step up filling method is carried out to reinforce the Yano method which is widely used to estimate volume ratio and self-weight consolidation settlement in reclamation area. This method considers actual reclamation construction in which dredged clay is continuously filled and rising of deposit height is presented as a result of volume decrease by height rising and self-weight consolidation. It measured the relationship between filling velocity and deposit rising velocity; calculated the total filling height which is needed to achieve the planned final deposit height, and its solid height and the time which is taken to finish the planned final deposit height; and on the basis of these calculated parameters, predicted the self-weight consolidation and volume change ratio in reclamation construction. Yano method is also used to predict the same conditions. 29.8% in self-weight consolidation, 31.1% in volume ratio, 40% in void ratio and water content is underestimated in Yano method compared to step up filling method.

• Clean Technology
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• v.17 no.1
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• pp.62-68
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• 2011

Hydrodynamic characteristics in multistage annular type fluidized bed (riser: $0.01{\times}0.025{\times}2.8m^3$, J-valve: $0.009{\times}0.015m^2$)were investigated. Glass beads ($d_p=101{\mu}m$, ${\rho}_b=1,590kg/m^3$, $U_{mf}=1.25{\times}10^{-2}m/s$, Geldart classification B) was used as a bed material. Accumulated weight by the electronic balance was measured to determine the solid flow rate in batch-type. In circulation condition, we measured the accumulated weight of particle transported from riser. At the steady state condition, solid circulation rate was calculated from time interval of the heated bed material passing between two thermocouples. Solid flow rate increased with increasing inlet gas velocity ($1.2-2.6U_{mf}$) and the static bed height (z, 0.24-0.68 m) from 2.2 to 23.4 kg/s. However, mean residence time decreased with increasing inlet gas velocity ($1.2-2.6U_{mf}$) and the static bed height (z, 0.24-0.68 m) from 1,438 to 440 s. The solid holdup in the riser was determined by measuring pressure differences according to the riser height. These results showed a similar trend to that of simple exponential decay type except for the top section of the riser. To verify the gas bypassing from top bubbling beds to middle bubbling beds, $CO_2$ gas was injected by tracer gas in constant ratio, and then was measured $CO_2$ concentration in outlet gas by gas chromatography. Gas bypassing occurred below 2.6% which is negligible value.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.492-501
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• 2009

This study was carried out to investigate influence of tree height on vegetable growth, productivity, and labor input in 5 year old slender spindle 'Fuji'/M.9 apple trees planted with the tree space of $3.2{\times}1.2m$ and trained to the tree height of 2.5m in the apple orchard of Apple Research Station, NIHHS, RDA in Gunwi County, Korea. Tree height was extended to the tree height of 4.0m for two years. And then, the tree height was restricted to 2.5 (control), 3.0, 3.5, and 4.0m in 8th year. Yield per 10a was 46, 25, and 4% higher at the tree height of 4.0, 3.5, and 3.0m than at the tree height of 2.5m respectively in first year and 17, 12, and 10% higher respectively, indicating the taller tree, the higher yield. Soluble solid contents was highest in the height of 2.5m than in any other treatments for 2 years, but fruit skin color was not clear. Labor input was increased parallel with the increase of tree height, but yield per labor input was decreased. Gross income and net income per 10a were increased parallel with the increase of tree height in first year, but not increased in second year. In considering production, labor input, and economic efficiency, the optimum tree height of slender spindle 'Fuji'/M.9 apple planted with the tree space of $3.2{\times}1.2m$ was presumed to be 3.0~3.5m.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.241-244
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• 2009

This paper deals with a usefulness verification of stretch forming process using flexible die. The stretch forming method is widely used in aircraft and high-speed train industries for manufacturing of skin structure, which is made of sheet metal. A great number of solid dies are originally used and developed for specific shapes with respect to different curvature radii of the skin structures. Accordingly, flexible stretch forming process is proposed in this study. It replaces the conventional solid dies with a set of height adjustable discrete punches. A usefulness of the flexible die is verified through extensive numerical simulations of the stretch forming process for simply curved sheet plate. The elastic recovery is considered and formability evaluations are conducted through a comparison of symmetry plane configurations.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.146-154
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• 1994

A series of numerical calculations are performed in order to investigate the dispersion mechanism of toxic gaseous and solid pollutants in extremely short-term and short range. The calculations are carried out in an open space characterized by turbulent boundary layer. The simulation is made by the use of numerical model, in which a control-volume based finite difference method is used together with the SIMPLEC algorithm for the resolution of the pressure-velocity coupling problem. The Reynolds stresses are solved by two-equation, k-$\varepsilon$ model modified for buoyancy. The major parameters consider-ed in this study are temperature, velocity and Injection height of toxic gases, environmental conditions such as temperature and velocity of free stream air, and topographic factor. The results are presented and discussed in detail. The flow field is commonly characterized by the formation of a strong recirculation zone due to the upward motion of the hot toxic gas and ground shear stress. The driving force of the upward motion is explained by the effect of thermal buoyancy of hot gas and the difference of inlet velocity between toxic gas and free stream.

• Journal of Korea Foundry Society
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• v.10 no.6
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• pp.520-527
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• 1990

In order to reduce segregation in 12%Cr steel ingots of 60-100tons, numerical analysis by computer was applied to simulate solidification profiles and the profiles of liguid-solid coexisting zone in accordance with the ratios of H(Height) /D(diameter) of 100-ton ingot. The result is that the ratio of L(vertical length) /D(diameter) of liquid-solid coexisting zone was reduced in proportion to the decrease of H/D ratio. With the reduced H/D ratio(0.92) of ingot, the segregation in 60-ton ingot of 12% Cr steel can be much reduced and recovery was also improved by reducing ingot weight.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.686-692
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• 2012

Solid free-form fabrication (SFF) technology was developed to fabricate three-dimensional (3D) scaffolds for tissue engineering (TE) applications. In this study, we developed a polymer deposition system (PDS) and created 3D microstructures using a bioresorbable polycaprolactone (PCL) polymer. Fabrication of 3D scaffolds by PDS requires a combination of several devices, including a heating system, dispenser, and motion controller. The system can process a polymer with extremely high precision by using a 200 ${\mu}m$ nozzle. Based on scanning electron microscope (SEM) images, both the line width and the piled line height were fine and uniform. Several 3D micro-structures, including the ANU pattern (a pattern named after Andong National University), $45^{\circ}$ pattern square, frame, cylindrical, triangular, cross-shaped, and hexagon, have been fabricated using the polymer deposition system.

• Transactions of Materials Processing
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• v.6 no.4
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• pp.329-337
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• 1997

Forging of an inner pulley for compressor clutch assembly of car air conditioner is investigated in this study. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and the outer one, and to make uniform the hardness distribution in the forged product. Using the rigid-plastic finite element simulation. we design the optimal process conditions, which has a performing operation. Also the final product configuration of forging has to be designed again in view of the metal flow involved in the operation, derived from the finite element simulations. The forged pulley is investigated by checking the hardness distribution and it is noted that the distribution has improved to be even and high enough for industrial application.

• Steel and Composite Structures
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• v.48 no.3
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• pp.263-273
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• 2023

This paper investigates dynamic characteristics of a graphene nanoplatelets reinforced composite (GNPRC) sandwich doubly curved shell based on the first-order shear deformation theory (FSDT) and Hamilton's principle. The sandwich doubly curved shell is fabricated from a core made of honeycomb materials sandwiched by composite GNPs reinforced face-sheets. Effective materials properties of composite face-sheets are assumed to vary based on Halpin-Tsai micromechanical models and rule of mixture. Furthermore, the material properties of honeycomb core are estimated using Gibson's formula. The fundamental frequencies of the shell are computed with changes of main geometrical and material properties such as amount and distribution type of graphene nanoplatelets, side length ratio, thickness to length ratio of and side length ratio of honeycomb. The Navier's technique is presented to obtain responses. Accuracy and trueness of the present model and analytical solution is confirmed through comparison of the results with available results in literature. It is concluded that an increase in thickness to length ratio yields a softer core with lower natural frequencies. Furthermore, increase in height to length ratio leads to significant decrease in natural frequencies.