• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.352-361
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• 2006

The grouting method is widely used in construction to reduce permeability and reinforce the ground. If the cement and grout material are not mixed well in the injection tip equipment, an opposite flow and Interception state of the chemical grouting can occur. McG method installs a special grouting device to allow better mixing of the grouting material and prevent backward flow. The block of nozzle also diversify powder rate of cement. YSS that lowers $Na_2O$ and thereby increases durability is developed by gel-forming reaction material. In this study, the seepage state and unconfined compressive strength of the injection material using the special injection tip equipment is tested. The results of laboratory and field tests clearly demonstrate that the strength increases and permeability decreases using the McG method.

• Korean Journal of Construction Engineering and Management
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• v.25 no.1
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• pp.62-72
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• 2024

Due to the distribution structure of domestic temporary equipment, quality control of temporary equipment is essential because more than 80% of temporary equipment is repeated and reused. Due to this importance, the Ministry of Land, Infrastructure and Transport has proposed quality management standards for temporary equipment for 10types of temporary equipments, including steel pipe support, but the overall quality of temporary eqipment cannot be confirmed because the quality is managed through sampling quality tests. In addition, although quality control standards exist for temporary material rental company, practical utilization was investigated and analyzed to be very low as they are mainly presented based on qualitative inspection standards by visual inspection. Therefore, the purpose of this study is to develop individual temporary material/quality/delivery management standards (Guides) for temporary equipment rental company to preemptively secure the quality of temporary equipment before bringing them into the construction site. If the standards developed through this study are applied to domestic temporary equipment rental companies, it is expected that high-quality temporary equipment with secured quality will be brought into the construction site as the quality of temporary equipment quality of domestic medium and small temporary equipment rental companies is improved safety accidents related to temporary structures.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.1
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• pp.94-100
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• 2024

Recently, as interest in personal hygiene has increased due to the community spread of COVID-19 and variant viruses, fixed and potable UV germicidal equipment to sterilize indoor spaces and hand-held UV germicidal equipment to sterilize household items such as masks and mobile phones are continuously being developed and sold. However, the development and sales of the product are difficult because appropriate testing methods have not yet been established. In this situation, if an uncertified product is distributed in the market, it can cause serious harm to consumers. In this study, we investigate the photobiological risks and safety devices against UV exposure of UV germicidal equipment distributed domestically, and propose appropriate test methods for portable UV germicidal equipment based on the research results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.274-277
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• 2001

This paper describes the simulation study. conducted on the propagation characteristics of AE signal. In the case of gas insulation, such as $SF_6$, the equipment is less affected by the environment condition than air insulation, because the component parts of equipment were placed in the enclosure, which is filled with compressed gas. But. when the breakdown in the electric insulation occurs. it takes much time and economical efforts to repair. Therefore it is very important to diagnose the equipment before the accident. And. in general. UHF and AE signal is the most common transducer to diagnose the state of the power equipment, so, in this investigation, we make a experimental apparatus with aluminum plate and transient analysis with ANSYS to observe the propagation characteristics of AE signal. Through the result of the analysis. we can make a further understanding on the propagation characteristics of AE signal, and get the fundamental skills for the GIS diagnosis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.274-277
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• 2001

This paper describes the simulation study, conducted on the propagation characteristics of AE signal. In the case of gas insulation, such as SF6, the equipment is less affected by the environment condition than air insulation, because the component parts of equipment were placed in the enclosure, which is filled with compressed gas. But, when the breakdown in the electric insulation occurs, it takes much time and economical efforts to repair. Therefore it is very important to diagnose the equipment before the accident. And, in general, UHF and AE signal is the most common transducer to diagnose the state of the power equipment, so, in this investigation, we make a experimental apparatus with aluminum plate and transient analysis with ANSYS to observe the propagation characteristics of AE signal. Through the result of the analysis, we can make a further understanding on the propagation characteristics of AE signal, and get the fundamental skills for the GIS diagnosis.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.103-106
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• 2004

The new rheology fabrication process has been developed to rheo die casting and rheo forming process. Thixoforming process has disadvantages in terms of induction reheating process, scrap recycling, loss of raw material and cycle time. Therefore, to reduce the number of process, new rheology fabrication process with specially designed the rotational barrel type equipment has been proposed to apply in various part productions. The barrel type equipment, which could continuously fabricate the rheology materil, was specially designed to have a function to control cooling rate, shear rate and temperature. During the continuous rotation of barrel with a constant temperature, the shear rate is controlled with the rotation speed. The barrel surface has both the induction heating system and the cooling system to control the temperature of molten metal. By using this system, the effect of the rotation speed and the rotation time on the microstructure was widely examined. The possibility for the rheoforming process was investigated with microstructural characteristic.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.7
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• pp.449-453
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• 2016

The amount of electrical energy has been increased with the rapid development of the industrial society. Accordingly, operating voltage of the power equipment and facility capacity are continuously increasing. Development trends of recent high-voltage electrical equipment are ultra high-voltage, large-capacity and compact. Early diagnosis of a failure of the power plant has been emerging as an important task as to supply high quality power to users. In this study, we have tried to develope an algorithm for distinguishing an arc fault signal generated in the power plant by using UV sensor.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2387-2393
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• 2020

In this study, a gradient material for shielding neutrons and gamma rays was developed, which consists of epoxy resin, boron carbide (B₄C), lead (Pb) and a little graphene oxide. It aims light weight and compact, which will be applied on the transportable nuclear reactor. The material is made up of sixteen layers, and the thickness and components of each layer were designed by genetic algorithm (GA) combined with Monte Carlo N Particle Transport (MCNP). In the experiment, the viscosities of the epoxy at different temperatures were tested, and the settlement regularity of Pb particles and B₄C particles in the epoxy was simulated by matlab software. The material was manufactured at 25 ℃, the Pb C and O elements of which were also tested, and the result was compared with the outcome of the simulation. Finally, the material's shielding performance was simulated by MCNP and compared with the uniformity material's. The result shows that the shielding performance of gradient material is more effective than that of the uniformity material, and the difference is most noticeable when the materials are 30 cm thick.

• Journal of Korean Institute of Architectural Sustainable Environment and Building Systems
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• v.12 no.6
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• pp.543-556
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• 2018

Zero energy building was attended for energy consumption minimization by the energy saving technology about building heating and cooling energy consumption and the renewable energy production facility. So the government has supported the zero energy building supply for decreasing green gas emissions. The study about inventory of zero energy building has many proceeding. That inventory need the information of material and equipment. So information of material and equipment about zero energy building must be included for the zero energy building realization. Actually the database of zero energy building inventory construction through the inventory established studies has difficult because the database need many information. In this study, author proposed the test methods and performance reference for upload at inventory. It was constructed to material - module - package. Also the author analyzed the construction of the technical package for zero energy building. The author separated performance category to the energy performance for energy analysis and other performance for confirmed the durability, stability and etc. This performance category proposed the table. The test methods of material and equipment in the passive package and active package proposed to the international standard and korea standard basically korea standard. Also the performance reference was proposed to korea legal standard and various standard by this study results. And the authors proposed the table of performance value, test methods, performance reference. By result of this study, the test methods and performance reference will be used the basic data for inventory of zero energy building.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.574-574
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• 2005

To found out the degradation characteristic of transformer insulation, insulation material was depisited into transformer oil and heated. Due to the thermal stress which added to insulation, the density of carbon dioxide which included in transformer oil was mesured by using the gas density detection equipment of gas sensor and air circulation method. As a result, it didn't match with the transformer supervision standard. But it was found that as thermal stress increased, the density of carbon dioxide propertionally increased.