• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.155-160
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• 2005

Gravity thickening process has been widely used in WTP sludge thickening at domestic water treatment plant. The operation method of the process is very simple, however, the process requires long detention time about 24~48 hours for sludge thickening, uses polymer, and low total solids of thickened sludge to increase sludge thickening efficiency. To solve there problems, we studied about flotation process, especially, electro-flotation (EF) process in WTP sludge thickening. Electro-flotation process is simpler than dissolved-air-flotation(DAF) process because EF needs only electrode and current to generate micro-bubbles and the operation is easy. This study was performed at two batch columns to compare interface height, total solids, effluent turbidity between an electro-flotation thickening and a gravity thickening. According to the result, an electro-flotation thickening was that interface height was decreasing, total solids had high concentration, and effluent turbidity was low in comparison with a gravity thickening. Also, it will make the high efficiency of following process, such as a dehydrating process and digestive process. because of high total solids and low moisture content in the sludge.

• Food Science of Animal Resources
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• v.41 no.6
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• pp.983-996
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• 2021

This study explored the physicochemical, textural, and sensorial properties of a meat analog (MA) as compared to beef and pork meats. Results illustrate that MA patties had lower moisture, fat, and protein content, as well as higher ash and crude fiber than beef and pork. Likewise, MA patties had a higher pH, lightness (L^*), and redness (a^*) than either beef or pork. Pork meat exhibited the highest released water (RW) and cooking loss (CL) values, followed closely by MA with beef displaying the lowest values. Regardless of patty type, the post-cooking diameter patties were reduced significantly (p<0.05). However, the Warner-Bratzler shear force (WBSF), hardness, chewiness, and gumminess of beef were significantly higher than that of either pork or MA. The visible appearance of MA patties had more porous and loose structures before and after cooking. Consequently, based on sensory parameters, MA patties demonstrated the higher values for appearance and firmness, followed by beef and pork respectively, although the difference was not statistically significant. Therefore, the current study demonstrated that some physicochemical, textural, and sensory characteristics of beef and pork exhibited the most similarity to MA.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.4
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• pp.17-26
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• 2024

This study aimed to design and build a web-based decision support system for wheat cultivation management. The system is designed to collect and measure the weather environment at the growth stage on a daily basis and predict the soil moisture content. Based on this, APSIM, one of the process-based crop models, was used to predict the potential yield of wheat cultivation in real time by making decisions at each stage. The decision-making system for wheat crop management was designed to provide information through a web-based dashboard in consideration of user convenience and to comprehensively evaluate wheat yield potential according to past, present, and future weather conditions. Based on the APSIM model, the system estimates the current yield using past and present weather data and predicts future weather using the past 40 years of weather data to estimate the potential yield at harvest. This system is expected to be developed into a decision support system for farmers to prescribe irrigation and fertilizer in order to increase domestic wheat production and quality by enhancing the yield estimation model by adding influence factors that can contribute to improving wheat yield.

• Food Science of Animal Resources
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• v.36 no.3
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• pp.291-299
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• 2016

Interaction between carcass quality grade and end-point cooking temperature on eating quality of Hanwoo m. longissimus was investigated. Ten (10) of steers were sampled from a commercial population; carcasses with QG 1⁺⁺ (n=5) and QG 1 (n=5) were chosen. Samples were cooked by electric oven at 60 or 82℃ and compared with uncooked control samples. The pH was not affected by cooking temperature but decreased the redness after cooking and steaks cooked at 60℃ were more reddish than steaks cooked at 82℃ in both QG groups. Higher cooking temperature greatly (p<0.05) increased the cooking loss, but there was no significant interaction between cooking temperature and QG on the cooking loss. Moisture is negatively correlated with temperature in both QG while the proportionate relationship between crude fat and end-point temperature found in QG 1⁺⁺. WBSF values were significantly (p<0.05) high for QG 1, while that was significantly (p<0.05) increased when the temperature continues to increase. The increasing quality grade of beef resulted in significant higher (p<0.01) level of TBARS and cooking temperature increased TBARS content. Fatty acid composition was not altered by cooking at both temperatures and also the amount of fat intake was not changed. The current study indicates that eating quality of beef m. longissimus was greatly influenced by end-point temperature being interacted with QG. However, the amount and composition of fat were stable regardless of end-point temperatures. These results will provide a consumer reference to determine cooking conditions and intramuscular fat content.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.630-638
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• 2001

The electrical resistivity of sinter dusts generated from the steel industry and coal fly ash from the coal power plant has been investigated using the high voltage conductivity cell based on JIS B 9915 as a function of temperature and water content. Dust characterization such as the chemical composition, size distribution, atomic concentration, and surface structure has been conducted. Major constituents of sinter dusts were Fe$_2$O$_3$(40∼74.5%), CaO (6.4∼8.2%), SiO$_2$(4.1∼6.0%), and unburned carbon (7.0∼14.7%), while the coal fly ash consisted of mainly SiO$_2$(51.4%), Al$_2$O$_3$(24.1%), and Fe$_2$O$_3$(10.5%). Size distributions of the sinter dusts were bi-modal in shape and the mass median diameters (MMD) were in the range of 24.7∼137㎛, whereas the coal fly ash also displayed bi-modal distribution and the MMD of the coal fly ash was 35.71㎛. Factors affecting resistivity of dusts were chemical composition, moisture content, particle size, gas temperature, and surface structure of dust. The resistivity of sinter dusts was so high as 10(sup)15 ohm$.$cm at 150$\^{C}$ that sinter dust would not precipitate well. The resistivity of the coal fly ash was measured 1012 ohm$.$cm at about 150$\^{C}$. Increased water contents of the ambient air lowered the dust resistivity because current conduction was more activated for absorption of water vapor on the surface layer of the dust.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.205-205
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• 2017

An excess soil water condition is one of the major problems for the field crops growing in paddy fields because of their poor drainage and less availability for oxygen uptake which leads to adversely affect the photosynthesis. Therefore, the current study was undertaken with aim to investigate the effects groundwater level on the photosynthetic response of soy bean (Urum), red bean (Arari), sesame (Geonbaek), perilla (Dayu) after the transplanting to the lysimeter to investigate the plant-water relation and their effect on photosynthesis. The chlorophyll content of the crops according to the humid conditions of the soy bean, sesame and the perilla was found to be 5%, 6.89 % and 13.7% higher than that of the groundwater treated at 40cm, respectively. On the other hand, the chlorophyll content of adzuki bean decreased 6.6% from the groundwater level of 40cm, and the sorghum decreased by 5.7%. As a result of investigating the Fv / Fm value of groundwater, the adzuki bean at 20cm above groundwater was lower than that of groundwater by 40cm immediately before flowering. The Fv / Fm value of soy bean and sesame at 40cm above groundwater were lowered by flowering under groundwater 20 cm and Fv / Fm value of sorghum is increased at 40 cm treatment immediately before flowering while the Fv / Fm values of the perilla had no significant difference in comparison to those at 20 cm and 40 cm of groundwater. In the case of chlorophyll fluorescence reaction, it is known that the when the absolute value is closer to 0.82, the stress is considered less. As a result of comparing the numerical values of the crops, it was found that the sorghum was the most stressed followed by adzuki bean and sesame, while the soy beans and perilla was found on the average, as they received less stress.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.287-296
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• 2014

The physicochemical and functional traits for loin muscles of Hanwoo steers were compared by quality grade (QG). A total of 500 Hanwoo steers were slaughtered, their carcasses were categorized into four groups (QG 1++, 1+, 1, and 2), and the longissimus dorsi muscles were analyzed. QG 1++ group had the highest fat and lowest moisture content (p<0.05). QG 1++ showed higher $L^*$ and $b^*$ color values, higher cooking loss, and lower shear force values, compared with the other groups (p<0.05). The flavor, tenderness, juiciness, and preference scores by sensory evaluation were highly ranked for premium QG groups (1++ and 1+). Regarding the micro compounds, QG 1 and QG 2 had greater amounts of inosine monophosphate, and QG 2 had greater amounts of anserine, carnosine, and creatine, than QG 1++ (p<0.05). QG 1++ and 1+ had higher percentages of oleic acid (C18:1) than QG 2 (p<0.05). Within premium QG 1++ and 1+, the results of the nucleotides, free amino acids, dipeptides, and fatty acids did not show any distinctive differences. Hanwoo beef as determined by the current grading system was not significantly different in terms of functional components; the only significant difference was in intramuscular fat content.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.327-338
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• 2014

Relationship between growth rate and wood quality was investigated by physical and mechanical properties with Quercus rubra (24 years old) from five different origin of apricot. In greenwood moisture content, sapwood had higher moisture content than heartwood, and there was difference among different origin of apricot. There were different specific gravity of wood among different origin of apricot. Compared with higher growth rate with higher specific gravity in sapwood, opposite trend was observed in heartwood. There were difference in shrinkage based on origin of apricot, and higher growth rate wood had higher shrinkage and T/R ratio. Compression Young's modulus, bending strength, bending Young's modulus, and compact strength was difference among different origin of apricot. Higher growth rate wood had higher tensile strength, and also there was difference amont different origin of apricot. In hardness, 3 different directions had all difference among different origin of apricot, and higher growth rate wood showed higher hardness than others. Based on overall physical and/or mechanical properties and growth rate, apricot from Bancroft was best quality in current.

• Geophysics and Geophysical Exploration
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• v.16 no.2
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• pp.79-90
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• 2013

Geophysical investigation in non-destructive testing is economically less expensive than boring testing and providing geotechnical information over wide-area. But, it provides only limited geotechnical information, which is hardly used to the design. Accordingly, we performed electrical resistivity experiments on large scale of soil model to analyze the correlation between electrical resistivity response and soil water contents. The soils used in the experiments were the Jumunjin standard sand and weathered granite soil. Each soil particle size distribution and coefficient of uniformity of experimental material obtained in the experiments were maintained in a state of the homogeneous. The specifications of the model used in this study is $160{\times}100{\times}50$(cm) of acrylic, and each soil was maintained at the height 30 cm. The water content were measured using the 5TE sensors (water contents sensors) which is installed 7 ~ 8 cm apart vertically by plugging to floor. The results of the resistivity behavior pattern for Jumunjin standard sand was found to be sensitive to the water content, while the weathered granite soil was showing lower resistivity over the time, and there was no significant change in behavior pattern observed. So, it results that the Jumunjin standard sand's particle current conduction was better than the weathered granite soil's particle through contact with the distilled water. This lab test was also compared with the result of a test bed site composed of similar weathered soil. It was confirmed that these experiments were underlying research of non-destructive investigation techniques to improve the accuracy to estimate the geotechnical parameter.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.3
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• pp.149-155
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• 2020

Cattle feeding in South Korea has been heavily dependent on domestically produced rice straw and imported grain. Around 42% of domestically produced rice straw is utilized for forage, and the remainder is recycled to restore soil fertility. Approximately 35% of round baleages were made with rice straw. However, higher quality hay is desired over rice straw. Due to increasing stockpiles of rice, there has been an economic burden on the government to store the surplus; therefore production of annual forage crops in rice fields has been further promoted in recent years. Hay import from the USA currently constitutes more than 80% of total imported hays. The main imported hays are alfalfa (Medicago sativa), timothy (Phleum pretense), and tall fescue (Festica arundinacea). The estimated forage required for cattle feeding was approximately 5.4 million MT in 2016. Domestically produced forage sates only 43% of that value, while low quality rice straw and imported hay covered the rest of demand by 33% and 20%, respectively. As utilization of domestically produced forage is more desirable for forage-based cattle production, long-term strategies have been necessary to promote domestic production of high quality baleage. One such strategy has been utilizing the fertile soil and abundance of fallow rice fields of western region of S. Korea to produce forage crops. Italian ryegrass (Lolium multiflorum) is the most successfully produced winter annual in the region and is approximately 56% of the total winter annual forage production. Forage sorghums (Sorghum bicolor), sorghum × sudangrass hybrids, and hybrid corn (Zea mays) produce a substantial amount of warm-season forage during summer. Produced forage has been largely stored through baleage due to heavy dew and frequent rains and has been evaluated according to S. Korea's newly implemented baleage commodity evaluation system. The system weighs 50% of its total grading points on moisture content because of its importance in deliverable DM content and desirable baleage fermentation; this has proved to be an effective method. Although further improvement is required for the future of forage production in South Korea, the current government-led forage production in rice fields has been able to alleviate some of the country's shortage for quality hay.