• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.924-929
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• 2004

The objective of this study were to investigate the effect of ejaculation frequency on semen characteristics and to establish a method for quick assessment of sperm concentration in TCC using packed cell volume (PCV) as the parameter (Trial 1). Eighty senior roosters, averaging 61 wk-old, were used and the sperm concentrations were determined using a hemacytometer. The PCV value was measured in a capillary (0.75 mm in inner diameter) by centrifugation. A simple linear regression analysis suggested that the sperm concentrations were significantly correlated with PCV values (r=0.62, p<0.001). Trial 2 was conducted to determine the optimal ejaculation frequency of TCC roosters in a weekly semen collection program. The male birds were subjected to 1, 2, 3 or 6 ejaculations per week for four consecutive weeks and semen characteristics including ejaculation volume (EV, mL), sperm motility (%), PCV (%), sperm concentration (ESC, $\times$10$^{9}$/mL), weekly sperm production (WSP, $\times$10$^{9}$/wk) and average motile sperm numbers (AMSN, $\times$10$^{9}$/ejac) were determined. Average EV was greater in the group with 3 ejac/wk than with only 1 ejac/wk in weeks 1 and 3 of the collection period. WSP increased with ejaculation frequency during the first 3 weeks of collection (p<0.05). Sperm motility was better in the birds with 6 ejac/wk than in single ejaculation group for the first 2 wk and no significant differences were found for the last 2 wk of study. In contrast, the PCV value showed a trend of reduction for the first 2 wks in the 6 ejac/wk group. Surprisingly, no significant differences were detected in the AMSN among treatment groups. The weekly motile sperm production (WMSP) increased with ejaculation frequency. Based on our observation, PCV values could be used for a quick estimation of sperm concentration and an intensive semen collection program enhanced weekly sperm production in TCC roosters.

• Journal of Bio-Environment Control
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• v.14 no.3
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• pp.160-165
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• 2005

Since the growth and quality of oak mushrooms are sensitively affected by environmental conditions, an adequate environmental control is very essential to improve the yield and quality under protected cultivation. In this study, the diameter, thickness, length and hardness of cap and stipe, the dry weight, fresh weight and moisture content of the mushrooms were analyzed under the environmental conditions such as night air temperatures (control, $5{\~}11^{\circ}C$ and $12{\~}18^{\circ}C$), relative humidities in the daytime (control, humidifying for 6 h and 12 h), and wind velocities (control, fan-operation for 6 h and 12 h). At a lower night temperature, the quality of the mushrooms was improved, and considered to be optimum at $3{\~}8^{\circ}C$ in terms of fresh weight and quality. At $70{\~}80{\%}$ of relative humidity in the daytime, the fresh weight was increased, but the quality decreased. Considering the quality, the relative humidity in the daytime is adequate at around $50{\%}$. At 6 h of maintaining the wind velocity at $1{\~}2\;my{\cdot}s^{-1}$, the growth and quality were better, but the lightness became higher at 12 h although the fresh weight was reduced by evaporation. It is concluded that even though both of the yield and quality are not easily improved at a same time, optimum approaches should be required by using the relationship among environmental factors and the growth and quality.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.85-95
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• 2012

This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges using nonlinear finite element analysis method. Cable-stayed bridges exhibit various geometric nonlinearities as well as material nonlinearities, so rational nonlinear finite element analysis should be performed for investigation of the ultimate behavior. In this study, ultimate behavior of steel cable-stayed bridges was studied using rational ultimate analysis method. Nonlinear equivalent truss element and nonlinear frame element were used for modeling the cable, girder and mast. Moreover, refined plastic hinge method was adopted for considering the material nonlinearity of steel members. In this study, the 2-step analysis method was used. Before live load analysis, initial shape analysis was performed in order to consider the dead load condition. For investigation of the ultimate behavior of steel cable-stayed bridges, analysis models which span length is 920.0 m were used. Radiating type and fan type were considered as the cable-arrangement types. With various quantitative evidences such as load-displacement curves, deformed shapes, locations of the yield point or region, bending moment distribution and so on, the ultimate behavior of steel cable-stayed bridges was investigated and described in this paper.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.336-342
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• 2012

This study was carried out in order to compare the residue levels of pesticides among lettuce, kale and perilla leaf depending on the morphological characteristics of plant. Residue levels were investigated at the zero, second, fifth days after last application, 9 species of systemic or non-systemic pesticide were twice applied with 7 days interval by knapsack power sprayer with 2 heads fan shape nozzle. Ratios of leaf area to weight ($cm^2$ $g^{-1}$) were 58 of perilla leaf, 27 of lettuce and 23 of kale. Ratios of leaf area to weight of perilla leaf was 2.1 times higher than that of lettuce. Residue levels of perilla leaf were 1.3 to 2.3 times higher than those of lettuce at the day of spraying and 1.3 to 3.3 times higher at the fifth day. Therefore the differences of pesticide residues between perilla leaf and lettuce were affected by the ratio of leaf area to weight. Residue levels in lettuce were 2.4 to 7.3 times higher than those in kale at the day of spraying because the adhesive effect of pesticide particles on kale leaf was low.

• Journal of Animal Science and Technology
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• v.56 no.5
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• pp.18.1-18.5
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• 2014

Background: A six-week study involving two hundred and fifty (250) Harco Black layer birds at point of lay was conducted to investigate the effects of potential natural colorant on performance and Egg quality traits. The birds were assigned to five (5) dietary treatments, each containing supplements either of control, Baobab Leaf (BL), Waterleaf (WL), Red Pepper (RP), Canthaxanthin (CTX) at 40 g/kg feed and 50 mg/kg feed of natural and commercial colorants, respectively. Results: Performance records shows that there was no significant (p > 0.05) difference in feed intake across the supplements of Red pepper, Water leaf, Canthaxanthin and control diet, however, birds fed Baobab leaf treatment had a significantly lower (p < 0.05) feed intake value (94.07 g) when compared with other treatments. Body weight gain and Hen Day Production were not significant influenced (p > 0.05) by the dietary treatments, although laying hens fed Baobab leaf supplement had lowest mean HDP of 48.80%, while birds fed Red pepper and Water leaf supplement had an average value of 52.79%. There was no significant effect (p > 0.05) of colorants on egg external traits, compared with the control; birds fed Canthaxanthin treatment had higher mean egg weight (51.79 g), egg length (4.55 g), egg breadth (3.29 g); Red pepper treatment had highest mean shell thickness (0.29 g), however these differences were not significant (p > 0.05). Yolk height, Albumen height, Yolk index, and Haugh unit were not significantly affected (p > 0.05) across treatments. Yolk width was lowest (p < 0.05) in Baobab leaf treatment (2.54 cm); Red pepper, Water leaf and Canthaxanthin (2.89 cm, 2.62 cm and 2.89 cm respectively) were not significantly (p > 0.05) different from the control (2.73 cm). Yolk colour score was significantly highest (p < 0.05) in Red pepper treatment (7.50); Water leaf, Baobab leaf and Canthaxanthin ranged between 2.25-3.31 on the DSM yolk colour fan, Control treatment had the lowest yolk colour score (p < 0.05) of 1.31. Conclusion: The study showed Red pepper as a worthy alternative to commercial yolk colorant. Water leaf and baobab are not good substitutes for canthaxanthin as a yolk colourant.

• Journal of Biosystems Engineering
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• v.43 no.3
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• pp.237-246
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• 2018

Purpose: This study (a) investigated the effect of microwave power intensity and sample thickness on microwave drying characteristics of radish strips, and (b) determined the best-fit drying model for describing experimental drying data, effective moisture diffusivity ($D_{eff}$), and activation energy ($E_a$) for all drying conditions. Methods: A domestic microwave oven was modified for microwave drying and equipped with a small fan installed on the left upper side for removing water vapor during the drying process. Radishes were cut into two fixed-size strip shapes (6 and 9 mm in thickness). For drying experiments, the applied microwave power intensities ranged from 180 to 630 W at intervals of 90 W. Six drying models were evaluated to delineate the experimental drying curves of both radish strip samples. The effective moisture diffusivity ($D_{eff}$) was determined from Fick's diffusion method, and the Arrhenius equation was applied to calculate the activation energy ($E_a$). Results: The drying time was profoundly decreased as the microwave power intensity was increased regardless of the thickness of the radish strips; however, the drying rate of thicker strips was faster than that of the thinner strips up to a certain moisture content of the strip samples. The majority of the applied drying models were suitable to describe the drying characteristics of the radish strips for all drying conditions. Among the drying models, based on the model indices, the best model was the Page model. The range of estimated $D_{eff}$ for both strip samples was from $2.907{\times}10^{-9}$ to $1.215{\times}10^{-8}m^2/s$. $E_a$ for the 6- and 9-mm strips was 3.537 and 3.179 W/g, respectively. Conclusions: The microwave drying characteristics varied depending on the microwave power intensity and the thickness of the strips. In order to produce high-quality dried radish strips, the microwave power intensity should be lower than 180 W.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.225-231
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• 2002

The physicochemical characteristics of pine nuts gruel were investigated to find the effects of processing condition during the processing. Three-dimensional response surface methodology was applied to investigate effects of ratio of water volume and pine nuts weight to rice weight and heating time on dependent variables of the physicochemical characteristics. The dependent variables in physicochemical characteristics were viscosity (cP), spreadability (cm), pH, soluble solid content (%), color, total sugar (%) and amylose content (%). The F-value of ratio of water volume and pine nuts weight to rice weight and heating time to viscosity were 8.91, 4.54 and 5.02 respectively and they are significantly different at 5% level. The F-value to spreadability were 5.44, 7.88 and 8.04 respectively and they are significantly different at 5% level. These results suggest that water volume, pine nuts weight and heating time greatly affect the viscosity and spreadability of pine nuts gruel. The processing condition also affect the soluble solid content. The changes of the processing condition did not affect the pH of pine nuts gruel. We found that the L, a, b value were affected more by ratio of water volume and pine nuts weight to rice weight than by heating time. The water volume affected more the total sugar and amylose content of pine nuts gruel than pine nuts weight and heating time.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.265-276
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• 2020

This study was conducted to provide a basis for raising farm income by increasing the yield and extending the cultivation period by creating an environment where crops can be cultivated normally during high temperatures in summer. The maximum cooling load of the multi-span greenhouse with a floor area of 504 ㎡ was found to be 462,609 W, and keeping the greenhouse under 32℃ without shading the greenhouse at a high temperature, it was necessary to fog spray 471.6 L of water per hour. The automatic fog cooling control device was developed to effectively control the fog device, the flow fan, and the light blocking device constituting the fog cooling system. The fog cooling system showed that the temperature of the greenhouse could be lowered by 6℃ than the outside temperature. The relative humidity of the fog-cooled greenhouse was 40-80% during the day, about 20% higher than that of the control greenhouse, and this increase in relative humidity contributed to the growth of cucumbers. The relative humidity of the fog cooling greenhouse during the day was 40-80%, which was about 20% higher than that of the control greenhouse, and this increase in relative humidity contributed to the growth of cucumbers. The yield of cucumbers in the fog-cooled greenhouse was 1.8 times higher in the single-span greenhouse and two times higher in the multi-span greenhouse compared to the control greenhouse.

• Elastomers and Composites
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• v.40 no.3
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• pp.166-173
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• 2005

Effect of thermal aging on the weight loss and water absorption of epoxy adhesives was investigated in the presence of three types of different hardeners, such as D-230, G-5022, and HN-2200. Thermal and mechanical properties of the cured epoxy resins were also studied througth the glass transition temperature and shear adhesion strength measurements. Weight losses of DGEBA/D-230 and DGEBA/HN- 2200 systems were not varied. However, the weight of DGEBA/G-5022 system was significantly decreased with increasing the thermal aging time. The water absorption of the specimens was increased as the thermal aging time increased except that using G-5022. DEGBA/HN-2200 system showed higher $T_g$ value than those of other systems, due to the formation of the fine three-dimensional network structure containing aliphatic ring. Shear adhesion strength of all systems was increased with increasing the thermal aging tine, which is attributed to increased degree of cure and fine three-dimensional network structure formation. And $T_g$ values and shear adhesion strength of all specimens exposed to water was decreased as the immersion time increased.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.304-310
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• 2011

To evaluate the effect of curing treatment using a newly developed simplified curing unit (SCU) on the physicochemical quality of stored sweet potatoes was investigated for six months. The SCU consisting of a heater, an air circulation fan, exhaust fans, and a humidifying duct was installed in a cold storage room where the harvested sweet potatoes were stacked. During the six days of curing treatment, air temperature and relative humidity in the storage room were set at $32^{\circ}C$ and 90%, respectively. Physical and chemical properties of sweet potatoes were measured at 1-month intervals from the first day of storage. McKinney index showing the incidence and severity of decay was 0.83% in the curing treatment, while that of untreated control was 5.08% over the same storing period. Firmness, soluble solids content, and dry matter content in the cured sweet potatoes were greater than those of untreated control. Moreover, the changes of skin color in uncured potatoes occurred rapidly than cured one which showed delay of skin discoloration during the long-term storage. Results suggest that the SCU treatment improves the physicochemical quality of stored sweet potatoes and extends their storability. Therefore, the SCU can be effectively used for curing treatment of sweet potatoes with a relatively low cost.