• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.349-356
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• 2006

At present, the selecting system and analytic estimation criterion on repair materials and methods of the deteriorated RC structures have not yet been set up in domestic. Under these circumstances, deterioration such as shrinkage crack, corrosion of rebar has been often occurred after repair, and this finally results in too frequent repairs. In this study, three types of repair methods were experimentally investigated by the accelerating test in a combined deterioration chamber and long-term field exposure test. Three types of repair methods applied in this study belong to a group of polymer cement mortar, which is commonly used in repair works. According to the results of this study, durability of repair mortar layers and corrosion properties of recovered rebar could be investigated in short period by the accelerating test in a combined deterioration chamber, which can simulate the condition of repeated high-and-low temperature and repeated dry-and-wet environment, spraying chloride solution and emitting $CO_2$ gas. After 36 month long-term filed exposure test in the coastal area, harmful macro-cracks are observed in the polymer cement mortar layer of some repair methods. These crack are considered to result from drying shrinkage of polymer cement mortar. Also, after 36 month exposure, amount of corrosion area and weight loss of rebar are found to be different according to the types of repair methods.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.50-50
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• 2017

Swampland is a potential alternative land to be used in various agricultural production activities in Indonesia, because Indonesia have 33.41 million hectares of swamp land that consists of 13.28 million hectares nontidal swamp and million hectares 20.13 tidal swamp. In the province of South Sumatra, because of unpredictable water level in the field before planting, farmers have been doing agronomic adaptation method through the delay time of transplanting and forced to apply more than one the nursery practice with the combination of a floating nursery method and a dry-bed nursery method. This study was aimed to (1) evaluate the seedling growth and tillering pattern of several popular Indonesian rice varieties, and (2) look for alternative technologies to get a better rice seedlings under two nursery methods in the nontidal swamp land. In the first experiment, the seedling growth characteristics of five rice varieties (Ciherang, Inpara 5, Inpara 9, Inpari 29, and Inpari 30) was evaluated by two methods of nursery, i.e. floating nursery and dry-bed nursery. In the second experiment, rice variety of Inpari 30 was treated with Zn seed priming and foliar fertilizer of 2,300 ppm N at the nursery stage. Those treatments were combined with the time of seedling under floating and dry-bed nursery. The results of the first experiment showed that of the five varieties tested, dry-bed nursery method showed better seedling growth than floating nursery. This was indicated by high leaf number, tiller number, tillers pattern, shoot-root ratio and relative growth rate. Ciherang and Inpari 30 showed high tiller number, and they had produced tertiary tiller in the sixth week of observation. Moreover, shorter period of floating and dry-bed nursery in combination with the treatment of Zn seed priming and spraying seedling with foliar fertilizer N could improve the growth of seedlings.

• Applied Chemistry for Engineering
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• v.29 no.2
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• pp.229-236
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• 2018

A customized cleaning agent was investigated for improving the performance decreased by the pollution of collecting plates in an electric fume collector (EFC) which was developed and applied for the purification of effluent gas including oil mist from the textile industry. The pollutants on the surface of collecting plates were blackened by the condensation of oil mist for a long time and difficult to remove by general cleaning agents. The composition of an optimized cleaning agent consisted of alkali, alcohol, glycol and non-ionic surfactant sources was determined by considering the pollutant properties and effect on the damage of the basic metal of collecting plate and so on. The developed cleaning agent solution diluted by 9.1% was applied to the field test, and also the pollutants strongly adhered on collecting plate surfaces were successfully removed by a simple spraying method. The effluent gas purification efficiency of EFC increased significantly by cleaning of collecting plates.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.149-155
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• 2004

On this study, a multipurpose operating system was developed to adjust a configuration of a moving path which have no connection with a form of greenhouse. To being performance the multipurpose working system, we have experienced growth quality on the plants in greenhouse. Some of the results are as follows. While watering by the hand spray. the condition of plant was generally no good. It was shown that plant height and leaf area were all high without wind during watering by the automatic spray. The effect to retrain a plant growth was high as a ventilation was strong. The diameter of a plant stem was small without ventilation condition during watering 3 times by automatic spray. The number of leaf was relatively large during 3 times by automatic spray compared to 2 times by automatic spray or hand spray. Growth of plant was fast as the times of spray were large.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.5
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• pp.338-344
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• 2016

Recent trends in transport system for carrying heavy freight are that demands of a high efficiency, economic efficiency, convenience and safety are increased. Conventional transport systems were poor in transport efficiency and economic efficiency. And Safety problems can be caused to products and workers. In order to overcome these problems, an air cushion transport device with a high-pressure air is required. The air cushion transporter is a device for reducing the frictional force of floor surface and lifting the heavy freight by spraying the high-pressure air to the floor. Technology to float and transfer freight using high-pressure air is very convenient and initial cost can be reduced. In this paper, the study on the levitation performance and transport efficiency of air cushion transport system is conducted and verified that air cushion transporter has a significantly higher transport efficiency than conventional heavy handling systems.

• Journal of Adhesion and Interface
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• v.14 no.2
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• pp.95-100
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• 2013

In this study, a series of hot-melt pressure sensitive adhesives (HMPSAs) based on metallocene polyolefin (me-PO) were prepared to investigate their possibility of replacing the HMPSAs based on styrenic block copolymers (SBCs). In addition, to optimize the performance of HMPSAs based on me-PO, several tackifiers having different softening point and molecular weight were evaluated. To achieve the HMPSAs which can satisfy the Dahlquist Criterion, hot melts required over 10% of process oil. To obtain the HMPSAs having low viscosity which can be applied by a spraying type applicator, secondary polymer having relatively low crystallinity was required. And, tackifier having high molecular weight attributed to increasing the cohesive strength of me-PO based HMPSAs.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.279-284
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• 2009

Traditionally, so-called "industrial waste gases", such ad exhaust from boilers at industrial installations and a large quantity of soot discharged from power station, before their release into the atmosphere, have been on occasion subjected to an air cleaning process to remove fine particles that may pollute the atmosphere (such as mist and dust containing various powdery or oily substances and moisture from industrial waste gases). The release of industrial waste gases containing these particles directly into the atmosphere poses a serious threat to the earth environment; and recovery of these noxious substances is required by law in some countries and local governments. in urban areas, air pollution from automobile exhaust and others creates a serious condition. Some homes are equipped with and use indoor air purifiers. In many of the kitchens of restaurants, smoke generated during cooking and otherwise contaminated air are cleansed by air purifiers before being released outside or recycled inside. For the dust collecting devices to recover the fine particles contained in contaminated air, the cause for air pollution and how to purify air, many types based on various principles are known. Specifically, classified based on theories of particle collection, filtration, gravity, inertia, centrifugation, electricity, and cleaning types are cited as available processes. Among them, an appropriate type is selected according to the size or type of fine particles to be collected and conditions for installation. For the efficiency of dust collection, a filtration system (by using bag filters and others) and electric system are particularly outstanding and are therefore used widely in various areas of industry. In this research, rotary type high performance oil mist and smoke collecting system with self auto cleaning device equipped with the cleaning fluid spraying section is investigated.

• Research in Plant Disease
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• v.21 no.2
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• pp.67-73
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• 2015

Bacterial blossom blight of kiwifruit (Actinidia deliciosa) caused by Pseudomonas syringae pv. syringae is known to be largely affected by weather conditions during the blooming period. While there have been many studies that investigated scientific relations between weather conditions and the epidemics of bacterial blossom blight of kiwifruit, no forecasting models have been developed thus far. In this study, we collected all the relevant information on the epidemiology of the blossom blight in relation to weather variables, and developed the Pss-KBB Risk Model that is based on the Maryblyt model for the fire blight of apple and pear. Subsequent model validation was conducted using 10 years of ground truth data from kiwifruit orchards in Haenam, Korea. As a result, it was shown that the Pss-KBB Risk Model resulted in better performance in estimating the disease severity compared with other two simple models using either temperature or precipitation information only. Overall, we concluded that by utilizing the Pss-KBB Risk Model and weather forecast information, potential infection risk of the bacterial blossom blight of kiwifruit can be accurately predicted, which will eventually lead kiwifruit growers to utilize the best practices related to spraying chemicals at the most effective time.

• Journal of the Korean Geotechnical Society
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• v.29 no.12
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• pp.25-34
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• 2013

This paper presents the results of a reduced-scale physical model investigation into the behavior of retaining walls subject to cycles of wetting and drying due to rainfall infiltration. Reduced-scale model walls equipped with a water spraying system that can simulate the wetting process were first constructed and a series of tests were conducted with due consideration of different rainfall intensities and backfill soil types. The results indicate that cycles of wetting and drying process have adverse effects on the wall behavior, increasing wall deformation as well as earth pressure acting on the wall, and that the first cycle of wetting and drying process has more pronounced effect on the wall performance than the ensuing cycles. It is also shown that the degree to which the wetting and drying cycles affect the wall behavior depends greatly on the backfill soil type, and that the larger the fine contents, the greater is the effect of cycles of wetting and drying on the wall behavior. Practical implications of the findings from this study are discussed in great detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.88-93
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• 2021

SAW (Submerged Arc Welding) is often used for ship construction or welding pressure vessels and involves spraying a flux in a powder form to a welding site to a certain thickness and continuously supplying electrode wires therein. This welding method enables high current welding up to 1,500 to 3,000 A. Arc efficiency is higher than 95% and the technique allows clean work as it creates less welding fume, which is composed of fine metal oxide particles, and the arc beam is not exposed. In this study, SM490C-TMC thick plates were heterogeneously welded by SAW. Mechanical properties of welds were measured, and welds were assessed macroscopically and for adhering magnetic particles. The following conclusions were drawn. Bending tests showed no spots exploded on sample surfaces or any other defect, and plastic deformation testing confirmed sufficient weld toughness. These results showed the 1F welding method has no shortcomings in terms of bending performance.