• Environmental Engineering Research
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• v.23 no.1
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• pp.54-61
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• 2018

Biodiesel production parameters and the impact analysis of the potential emissions from both soybean biodiesel and washing water stored in three different environmental conditions were investigated. The effects of the reaction temperature, methanol/oil mole ratio and catalyst concentration on biodiesel yield were considered. And the results showed optimum biodiesel yield of 99% obtained at $54^{\circ}C$, 7 methanol/oil mole ratio and 0.4 wt/wt % catalyst concentration. The potential emissions from both the biodiesel produced and washing water stored (for six weeks) in refrigerator (${\leq}10^{\circ}C$), vacuum (50 kPa) and direct exposure to atmosphere were identified and quantified. Impact analysis of the emissions involved their categorization into: terrestrial acidification, freshwater eutrophication, human toxicity, terrestrial ecotoxicity, climate change and freshwater ecotoxicity. Freshwater ecotoxicity category had the most pronounced negative impact of the potential emissions with $5.237710^{-2}kg\;1,4-DB\;eq$. emissions in Atmosphere, $4.702610^{-2}kg\;1,4-DB\;eq$. emissions in Refrigerator and $3.966110^{-2}kg\;1,4-DB\;eq$. emissions in Vacuum. Climate change had the least effect of the emissions with $6.214106^{-6}kg\;CO_2\;eq$. in Atmosphere, $3.9310^{-6}kg\;CO_2\;eq$. in Refrigerator and $1.6710^{-6}kg\;CO_2\;eq$. in Vacuum. The study showed that the order of preference of the storage environments of biodiesel is vacuum environment, refrigerated condition and exposure to atmosphere.

• Animal Bioscience
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• v.36 no.2
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• pp.229-237
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• 2023

Objective: This study evaluated the effects of dandelion supplements on lactation performance, circulating antioxidative activity and plasma metabolomics in primiparous dairy cows. Methods: A total of 60 mid-lactation dairy cows (milk yield = 34.29±0.34 kg/d; days in milk = 151.72±2.36 days) were divided into 4 treatment groups randomly, comprising the addition of dandelion at 0, 100, 200, 400 g/d per head. The experiment lasted for 8 weeks with an extra 10 days' pre-feeding period. Milk and blood samples were collected, and plasma samples were selected to perform metabolomics analysis. Results: Supplementing 200 g/d of dandelion increased the yield of milk and lactose (p≤0.05). The milk somatic cell counts (p≤0.05) were lower in all dandelion groups than those in the control group. The activity of glutathione peroxidase (p≤0.05) and superoxide dismutase (p≤0.05) were increased and plasma malondialdehyde (p = 0.01) was decreased when cows were fed 200 g/d dandelion. Plasma metabolomics analysis showed that 23 hub differential metabolites were identified in the 200 g/d dandelion group. These metabolites such as ribose, glutamic acid, valine, and phenylalanine were enriched in D-glutamine and D-glutamate metabolism (p = 0.06, impact value = 1), phenylalanine, tyrosine, and tryptophan biosynthesis (p = 0.05, impact value = 0.5), and starch and sucrose metabolism (p = 0.21, impact value = 0.13). Moreover, correlation analysis showed that circulating ribose, mannose, and glutamic acid were positively related to milk yield. Conclusion: Dandelion supplementation could improve lactation performance and elevate the plasma carbohydrate and amino acids metabolism and antioxidative activity. Supplementation of 200 g/d dandelion is recommended for lactating dairy cows.

• Journal of Animal Science and Technology
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• v.63 no.1
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• pp.77-90
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• 2021

This study aimed to assess the impact of abnormal climate events on the production of Italian ryegrass (IRG), such as autumn low-temperature, severe winter cold and spring droughts in the central inland, southern inland and southern coastal regions. Seasonal climatic variables, including temperature, precipitation, wind speed, relative humidity, and sunshine duration, were used to set the abnormal climate events using principal component analysis, and the abnormal climate events were distinguished from normal using Euclidean-distance cluster analysis. Furthermore, to estimate the impact caused by abnormal climate events, the dry matter yield (DMY) of IRG between abnormal and normal climate events was compared using a t-test with 5% significance level. As a result, the impact to the DMY of IRG by abnormal climate events in the central inland of Korea was significantly large in order of severe winter cold, spring drought, and autumn low-temperature. In the southern inland regions, severe winter cold was also the most serious abnormal event. These results indicate that the severe cold is critical to IRG in inland regions. Meanwhile, in the southern coastal regions, where severe cold weather is rare, the spring drought was the most serious abnormal climate event. In particular, since 2005, the frequency of spring droughts has tended to increase. In consideration of the trend and frequency of spring drought events, it is likely that drought becomes a NEW NORMAL during spring in Korea. This study was carried out to assess the impact of seasonal abnormal climate events on the DMY of IRG, and it can be helpful to make a guideline for its vulnerability.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.650-654
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• 2020

A combination of Polycarbonate (PC) material and Polymethylmethacrylate (PMMA), fabricated using an injection molding machine, has been investigated to determine its advantages, as studied in Ref. 1). This paper aims to investigate the optimization of PMMA/PC blend for both tensile yield strength and impact strength. Furthermore, interaction effects of process conditions on mechanical properties including tensile yield strength and impact strength of PMMA/PC blend by injection molding process are interpreted in this study. Tensile and impact specimens are designed following ASTM, type V, and are fabricated by injection molding process. The processing conditions such as melt temperature, mold temperature, packing pressure, and cooling time are applied; each factor has three levels. As a result, in comparison with optimization of separated responses, mechanical properties of PMMA/PC are found to decrease when optimizing both tensile and impact strengths simultaneously. The melt temperature is found to be the most significant interaction parameter with the mold temperature and packing pressure. In addition, there is more interaction between the mold temperature and cooling time. This investigation provides a useful understanding of the control of injection molding processing of polymer blends in optical application.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.163-168
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• 2006

Improvement of crop yield can be achieved through understanding genetic variation in reproductive characters and its impact on yield components. The present study was performed to evaluate genetic diversity for reproductive growth characters in exotic germplasm resources and to determine the relationships between developmental and growth periods with yield and yield components in soybean cultivar groups. For phenotypic evaluation such as reproductive and agronomic traits, a total of 80 indigenous and exotic soybean cultivars collected from four different geographical regions (China, Japan, Korea, and Vietnam) were grown from May to November of 2003 at the Seoul National University Farm, Suwon, Korea ($127^{\circ}02'E$ longitude, $37^{\circ}26'N$ latitude). Most of all the characters exhibited wide range of phenotypic variation, of which pod number, seed number, and plant yield showed greater range as compared to other characters. Korean cultivar groups showed greater diversity than the other cultivar groups in seven characters. Correlation analysis showed that days to flowering (DTF) and days to maturity (DTM) had close association with agronomic traits as well as yield and yield components. Both DTF and DTM had positive correlation with the other characters except one hundred seed weight. Stepwise multiple linear regression revealed that seed and pod number were identified as being significant for plant yield. The results in this study indicated wide variation in agronomic traits including DTF and DTM, suggesting the valuable genetic resources in a soybean breeding program.

• Journal of Drive and Control
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• v.21 no.2
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• pp.36-43
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• 2024

The yield is basic and necessary information in precision agriculture that reduces input resources and enhances productivity. Yield information is important because it can be used to set up farming plans and evaluate farming results. Yield monitoring systems are commercialized in the United States and Japan but not in Korea. Therefore, such a system must be developed. This study was conducted to develop a yield monitoring system that improved performance by correcting a previously developed flow sensor using a grain tank-weighing system. An impact-plated type flow sensor was installed in a grain tank where grains are placed, and grain tank-weighing sensors were installed under the grain tank to estimate the weight of the grain inside the tank. The grain flow rate and grain weight prediction models showed high correlations, with coefficient of determinations (R2) of 0.9979 and 0.9991, respectively. A main controller of the yield monitoring system that calculated the real-time yield using a sensor output value was also developed and installed in a combine harvester. Field tests of the combine harvester yield monitoring system were conducted in a rice paddy field. The developed yield monitoring system showed high accuracy with an error of 0.13%. Therefore, the newly developed yield monitoring system can be used to predict grain weight with high accuracy.

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.43-47
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• 2001

Effect of coupling agent on the mechanical properties of PP/GF blend was investigated. The flexural modulus, Izod impact strength, elongation at yield and tensile strength were improved with using coupling agent. Mopological studies revealed that PP and GF were incompatible and addition of coupling agent was very effective to enhance the compatibility, result in mechanical properties.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.7
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• pp.1044-1052
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• 2015

The aim of this modelling study was to investigate the effect of large herd size (and land areas) on walking distances and milking interval (MI), and their impact on milk yield and economic penalties when 50% of the total diets were provided from home grown feed either as pasture or grazeable complementary forage rotation (CFR) in an automatic milking system (AMS). Twelve scenarios consisting of 3 AMS herds (400, 600, 800 cows), 2 levels of pasture utilisation (current AMS utilisation of 15.0 t dry matter [DM]/ha, termed as 'moderate'; optimum pasture utilisation of 19.7 t DM/ha, termed as 'high') and 2 rates of incorporation of grazeable complementary forage system (CFS: 0, 30%; CFS = 65% farm is CFR and 35% of farm is pasture) were investigated. Walking distances, energy loss due to walking, MI, reduction in milk yield and income loss were calculated for each treatment based on information available in the literature. With moderate pasture utilisation and 0% CFR, increasing the herd size from 400 to 800 cows resulted in an increase in total walking distances between the parlour and the paddock from 3.5 to 6.3 km. Consequently, MI increased from 15.2 to 16.4 h with increased herd size from 400 to 800 cows. High pasture utilisation (allowing for an increased stocking density) reduced the total walking distances up to 1 km, thus reduced the MI by up to 0.5 h compared to the moderate pasture, 800 cow herd combination. The high pasture utilisation combined with 30% of the farm in CFR in the farm reduced the total walking distances by up to 1.7 km and MI by up to 0.8 h compared to the moderate pasture and 800 cow herd combination. For moderate pasture utilisation, increasing the herd size from 400 to 800 cows resulted in more dramatic milk yield penalty as yield increasing from c.f. 2.6 and 5.1 kg/cow/d respectively, which incurred a loss of up to $AU 1.9/cow/d. Milk yield losses of 0.61 kg and 0.25 kg for every km increase in total walking distance (voluntary return trip from parlour to paddock) and every one hour increase in MI, respectively. The high pasture utilisation combined with 30% of the farm in CFR in the farm increased milk yield by up to 1.5 kg/cow/d, thereby reducing loss by up to $0.5/cow/d (c.f. the moderate pasture and 800 cow herd scenario). Thus, it was concluded that the successful integration of grazeable CFS with pasture has the potential to improve financial performance compared to the pasture only, large herd, AMS.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.175-182
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• 2002

A new high yielding mulberry genotype, Victory-1 (V-1) was recommended to the field for irrigated areas by Central Sericultural Research and Training Institute (CSRTI), Mysore during 1996-1997. As K-2 and S-36 mulberry genotypes are already in the field, a study on the comparative performance of V-1, 5-36 and K-2 varieties, in terms of leaf yield, yield attributes, leaf moisture and moisture retaining capacity and their impact on silkworm rearing was carried out under Telangana conditions of Andhra Pradesh during 1999-2001. Among the three genotypes the leaf yield was found to be significantly (P < 0.01) higher in V-1 (64,130 kg/ha/yr) followed by S-36 (44,064 kg/ha/yr) and K-2 (23,990 kg/ha/yr). The maximum leaf moisture was also observed in V-1 (71.84%) compared to S-36 (66.86%) and K-2 (64%). The moisture retaining ability was more in V-1 (70.17%) followed by S-36 (66.20%) and K-2 (60.08%). The yield attributes were found to be significantly (P < 0.01) enhanced in V-1 over S-36 and K-2. Silkworm rearing results (bioassay) indicated a significant (P < 0.01) reduction in larval duration and improvement in larval weight, effective rate of rearing by number and weight, single cocoon and shell weights and shell ratio in the silkworm lots fed on V-1 variety followed by S-36 and K-2. Hence, in this study, V-1 was found to be superior among the three varieties studied.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.76-82
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• 2000

It is well known that during the oxygen cutting process residual thermal stresses are produced in weldment. The local non-uniform heating and subsequent cooling which takes place during any welding process causes complex thermal strains and stresses to finally lead to residual stresses exceed to the yield stress. High tensile stresses combined with applied structural load in the region near the welded joint can given rise to distortion brittle fracture change of the fatigue strength and stress corrosion cracking. The appropriate treatment of the welded component which reduces the peak of he welding residual stresses is believed to lower risk of the fracture during the service of the structure. In this study the impact loading in oxygen cutting frame was applied to reduce the residual stress. After applying the impact loading redistribution of resid-ual stress was measured by cutting method and the effect of fatigue was tested.