• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.424-431
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• 2016

The nutrients in livestock manure produced during fermentation processes in public livestock recycling centers are used as fertilizers. However, the large amounts of swine manure produced in intensive livestock farms can be a nonpoint source of pollution. In this experiment, we investigated the chemical properties, inorganic components, and heavy metal contents in 101 samples of liquid swine manure collected from 28 public livestock recycling centers throughout the nation. Results showed that the average pH of the samples was alkaline (pH range 5.18 to 9.54), and their maximum EC was $53.2dS\;m^{-1}$. The amounts of total nitrogen and total phosphorus were in the range of 1000 - 2000 and $200-800mg\;L^{-1}$ while potassium, which constituted 47% of the total inorganic ions recovered from the liquid swine manure, amounted to $1500mg\;L^{-1}$. The most distinctive heavy metals recovered from the liquid swine manure were copper and zinc although the amounts of both heavy metals were much lesser than those of the standards as livestock liquid fertilizer set by the Rural Development Administration. On the other hand, the amount of nitrogen decreased rapidly with an increasing fermentation period from immature to mature, assumed to be lost as volatile compounds, such as ammonia, which are the major odor components during the fermentation process.

• Korean Journal of Agricultural Science
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• v.43 no.3
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• pp.360-368
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• 2016

A more efficient use of nutrients can benefit both farmers and water quality. To propose an establishment scheme for official standards for liquid fertilizer from swine manure slurry, we evaluated previous and present data related to swine manure as well as analyzed 101 swine manure samples collected from 28 public livestock recycling centers throughout the nation. From these investigations, we found that the official standards for byproduct fertilizers set by the Rural Development Administration (RDA), especially for a liquid swine manure fertilizer, should be revised due to nutrient content requirements having to meet at least 0.3% content for the sum of nitrogen, phosphorus, and potassium. Otherwise, most of the swine manure cannot be utilized as a liquid fertilizer because the result of the 101 samples' analysis showed fewer than 28% of them met the minimum standard of ${\geq}0.3%$ content for the sum of nitrogen, phosphorus, and potassium, while the contents of heavy metals as indicators of toxicity met the standard requirements. Therefore, it is suggested that official standards for byproduct fertilizers set by RDA should be revised as follows: no limit for nutrient contents and addition of chloride as homogeneity. Also, NaCl should be changed to Na because NaCl cannot be analyzed by instrument.

• The Korean Fashion and Textile Research Journal
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• v.1 no.3
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• pp.288-295
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• 1999

This study was conducted to examine the fatigue phenomenon of mechanical properties in tencel fabrics by repeated washing & shear and tensile deformation. The obtained results are as follows. After performing repeated shear tensile deformation, RT of tencel showed higher increase rate than that of cotton and rayon, whereas its WT and EM was a smaller decrease rate than that of them. This means that tencel's resistance to tensile deformation was the greatest. In the repeated washing and shear tensile deformation, tencel's 2HB, 2HG and 2HG5 showed a remarkable increase rate. In terms of deformation frequency, the greatest change rate appeared at the time of 1000 cycles of repeated shear tensile deformation and 15 times of repeated washing. In the hand value and THV, KOSHI showed a higher increase rate for tencel than for cotton and rayon in both repeated washing and shear tensile deformation, and NUMERI showed a higher increase rate. In the THV the change rate of rayon and cotton could be rarely seen but for tencel, it decreased. tencel's change rate of thermal insulation value by materials was 1.08%, and it increased as the washing frequency increased, compared to the grey fabrics, whereas the change rates of cotton and rayon were 0.74% and 0.22%, respectively. The qmax decreased in the order of cotton>tencel>rayon as the washing frequency increased.

• Journal of The Korean Association of Information Education
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• v.22 no.3
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• pp.297-305
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• 2018

Physical computing is the concept of expanding computing to humans, environments, and objects. It draws attention as a programming learning medium based on physical outputs in integration of hardware and software. This study developed a programming learning model based on interactive prototyping using the characteristics of physical computing with a high degree of technical freedom and analyzed its learning effect in an experiment. To examine the effect of the experimental treatment, this researcher divided fifty nine 5th-grade elementary students into an experimental group and into a control group. the interactive prototyping programming learning model was applied to the experimental group, and a linear sequential programming learning model was applied to the control group. Information Science Creative Personality Test was conducted before and after the experimental treatment. Analysis of Covariance was conducted with the pre-test scores of the two groups. As a result, it was proved that there was the effect of learning at the significance level of .05. It indicates that the physical computing based interactive prototyping programming learning model is applicable to the programming learning for 5th-grade elementary students.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.4
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• pp.175-184
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• 2017

With the improvement of living standards, the ventilation for the mitigation of indoor or outdoor air-pollution problems has recently attracted a lot of attention. Consequently, the ventilation for the supply of outdoor fresh air into a room is treated as an important building-design factor. The ventilation is generally divided into the forced and natural types; here, the former can control the ventilation rate by using mechanical devices, but it has the disadvantages of the equipment costs, maintenance costs, and noise generation, while the latter is applied to most workshops due to the absence of noise and the low installation and maintenance costs. In this experimental study, the ventilation performance of a typical rotating-type natural ventilator, which is called a "wind turbine," was investigated with the outdoor-wind velocity and the indoor/outdoor-temperature difference. From the experiment results, it was confirmed that the temperature difference of $10^{\circ}C$ corresponds to the ventilation driving force with an outdoor-wind velocity of 1.0 m/s. Additionally, the intake-opening area of a building also exerts a great effect on the ventilation rates.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.5
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• pp.415-423
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• 2020

GNSS (Global Navigation Satellite System) is mostly used for high-precise surveys due to its accuracy and efficiency. But this technique does not always fulfill the demanding accuracy in harsh operational environments such as urban canyon and forest. One of the remedies for overcoming this barrier is to compose a heterogeneous surveying network by adopting terrestrial measurements (i.e., distances and angles). Hence, this study dealt with the adjustment of heterogeneous surveying networks consisted of GNSS baseline vectors, distances, horizontal and vertical angles with a view to enhancing their accuracy and so as to derive an appropriate scheme of the measurement combination. Reviewing some technical issues of the network adjustments, the simulation, and experimental studies have been carried out, showing that the inclusion of the terrestrial measurements in the GNSS standalone overall increased the accuracy of the adjusted coordinates. Especially, if the distances, the horizontal angles, or both of them were simultaneously adjusted with GNSS baselines, the accuracy of the GNSS horizontal component was improved. Comparing the inclusion of the horizontal angles with those of the distances, the former has been more influential on accuracy than the latter even though the same number of measurements were employed in the network. On the other hand, results of the GNSS network adjustment together with the vertical angles demonstrated the enhancement of the vertical accuracy. As conclusion, this paper proposes a simultaneous adjustment of GNSS baselines and the terrestrial measurements for an effective scheme that overcomes the limitation of GNSS control surveys.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1420-1425
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• 1998

Rice wines, Yakju-type, were brewed with typical raw materials plus powdered acorns, and storage qualities of the fermented wines were examined. Initial optical densities of the acorn added-rice wines were shown around 0.116 at 660 nm and then decreased to $0.06{\sim}0.075$ after 10 days storage at $4^{\circ}C$. Organic acid contents in the acorn added-rice wines were lower than that of the control: the contents were lactic, succinic, citric, malic, oxalic and fumaric acid in order; and gallic acid, a kind of tannic substances was 0.39 mg%. Peroxide values of the acorn added-rice wines were not markedly changed for 9 days, remaining as low as $2{\sim}3\;meq\;kg^{-1}$ lard of lard, but that of the control was increased to $265\;meq\;kg^{-1}$ lard. As the results of clarity, acidity and antioxidation, the acorn added-rice wines appeared to be preservable, owing to tannic substances extracted from acorn powder.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1491-1497
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• 2003

The improvement of abilities of utilizing information as well as the education of information is coming to the fore as a really significant matter for students living in knowledge and information-oriented society of the 21st century. In this respect, this study aims to develop a teaching and learning model for technical high school students who need mon desire and comprehensive faculty of their learning and to testify its efficiency by relating their abilities of using in with their curriculum. We propose a teaching and learning model, LT&T, which lets the students have academic interests and perform continuously learning activities by helping students themselves to find their achievements of learning and their learning ability. The LT&T teaching and learning model, proposed in this paper, is developed by combining LT and Tournaments, and it enhances individual several intellectual powers, and also activates the academic interests to increase the effects of learning. After we had a class using the LT and the LT&T, we conducted a sample survey of which results show that learning effects of LT&T is better than that of LT by students of more 80%.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.429-436
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• 2010

The purpose of this study was to analyze the kinematic factors and throwing variables for the 3-turn and 4-turn techniques and for release as well as to provide technical advice for improving athletic performance in hammer throwing. Data analysis led to the following conclusions: To increase the rotation speed for the 3-turn and 4-turn techniques, the time elapsed during the 1-foot support period should be decreased the distance between the rotating foot and the rotation axis should be small and the height of the hip joint should be increased at the times of release The throwing angle at the moment of release should be more than 40 degrees, and the throwing position should be taken vertically high at the shoulder joints. To accelerate the motion of the hammer, the speed should not be reduced during the 1-foot support period but should be increased during the 2-foot support period for much greater acceleration. In the 3-turn technique, the angles of the shoulder axis and hummer string should be dragged angle at the maximum point and lead angle at the minimum point, and dragged angle at the maximum and minimum points in the 4-turn at the time of relase The upper body should be quickly bent backward, the knee angle should be extended, and the angles of the shoulder axis and hammer string should be dragged angle close to 90 degrees.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.515-535
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• 2020

Essential oils (EOs) have gained a renewed interest in many disciplines such as plant disease control and medicine. This review discusses the components of ginger EOs, their mode of action, and their potential nanotechnology applications in controlling tropical plant diseases. Gas chromatography-mass spectroscopy (GC-MS), high-performance liquid chromatography, and headspace procedures are commonly used to detect and profile their chemical compositions EOs in ginger. The ginger EOs are composed of monoterpenes (transcaryophyllene, camphene, geranial, eucalyptol, and neral) and sesquiterpene hydrocarbons (α-zingiberene, ar-curcumene, β-bisabolene, and β-sesquiphellandrene). GC-MS analysis of the EOs revealed many compounds but few compounds were revealed using the headspace approach. The EOs have a wide range of activities against many phytopathogens. EOs mode of action affects both the pathogen cell's external envelope and internal structures. The problems associated with solubility and stability of EOs had prompted the use nanotechnology such as nanoemulsions. The use of nanoemulsion to increase efficiency and supply of EOs to control plant diseases control was discussed in this present paper. The findings of this review paper may accelerate the effective use of ginger EOs in controlling tropical plant diseases.