• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.519-524
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• 2022

Domestic building finishing materials are being evaluated according to KS F 2271 standards according to the notification of the Ministry of Land, Infrastructure and Transport, and this test is evaluated using laboratory animals. In this study, experiments were conducted on highly combustible organic insulation materials such as EPS, urethane, and phenolic foam. The purpose of this study was to analyze the cause of the behavioral suspension of the experimental mice by measuring the average behavioral suspension time of the mice caused by the harmful gas generated when these three types of insulation materials were burned. FTIR analysis and smoke density experiment were performed as a cause analysis method for the behavioral suspension of mice, and the experimental results were analyzed by dividing the causes of behavioral suspension into suffocation by particulate matter and toxic inhalation by gaseous substances. As a result of the test, urethane was evaluated as the most harmful insulation material, and as a result of FTIR analysis and smoke density test as a cause analysis for the gas toxicity test results, it is judged that the behavioral stop of the rats by suffocation is higher than the effect of toxic inhalation. This study is a basic study on the cause analysis of harmful gases, and it will be necessary to prepare the toxicity basis and analyze various materials and gases.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1135-1138
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• 2003

ERFs(Electrorheological Fluids) arc a complex system consisting of polarizable particles and insulation liquid. When an external electric field is applied to ERFs, its apparent viscosity increases dramatically. This phenomenon is called the ER effect. Generally, the behavior of ERFs has been modeled on those of Bingham fluids. But the behavior of ERFs differs from those of Bingham fluids in many respects. In the paper, ER effect concerning flow mode of ERFs is analyzed experimentally. According to several flow conditions, the change of ER effect is presented and visualized. A new modeling methodology of ER effect to reduce the modeling error is presented.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.1
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• pp.82-90
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• 2012

Four different buildings having various wall construction are analyzed for the effect of wall mass on the thermal performance and inside building air and wall temperature transient and also for calculating the energy consumption load. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equations is obtained using the Laplace transform method, Bromwich and modified Bromwich contour method. A simple dynamic model using steady state analysis as simplified methods is developed and results of energy consumption loads are compared with results obtained using the analytical solution. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from two different locations in Korea: Daegu having severe weather in summer and winter and Jeju having mild weather almost all year round. There is a significant wall mass effect on the thermal performance of a building in mild weather condition. Buildings of heavyweight construction with insulation show the highest comfort level in mild weather condition. A proportional controller provides the higher comfort level in comparison with buildings using on-off controller. The steady state analysis gives an accurate estimate of energy load for all types of construction. Finally, it appears that both mass and wall insulation are important factors in the thermal performance of buildings, but their relative merits should be decided in each building by a strict analysis of the building layout, weather conditions and site condition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.61-64
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• 2003

In the response to an increasing demand for electrical energy, much effort aimed to develop and commercialise HTS power equipments is going on around the world. For the development, it is necessary to establish the dielectric technology in $LN_2$. Hence many types of dielectric tests should be carried out to understand the dielectric phenomena at cryogenic temperature and to gather various dielectric data. Among the many types dielectric tests, the barrier effect were conducted with the simulated electrode after analysing the insulating configuration of the pancake coil type HTS transformer. The influence of a barrier on the dielectric strength was measured according to the size and the position of the barrier. It was shown that the effectiveness, the ratio of the breakdown voltage in presence of barrier to the voltage without barrier, is highest when the barrier is placed at the needle electrode side. And the barrier effect was not depend on the electrode array. The life time to breakdown with decreasing the applied voltage was increased remarkably having wide error band but the shape parameter in Weibull distribution was almost constant.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1216-1221
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• 2010

An industrial growth needs high quality of productivity and accuracy. So, the needs of power electronics became pressing. Recently both interest and demand about the technique of power electronics systems has been increased. Though power electronics has a lot of strong point, there are several problems which are harmonic effect, EMI(Electromagnetic Interference), malfunction of electric machinery, harmful effect on human, audible noise and so on. Because these problem are a potent influence on motor, so there needs the manufacture and redesign of motor. The real motors of industrial application have designed and manufactured on the basis of confidence. The study on motor using utility power source was verified sufficient to identify confidence of electric machinery on utility power source. However, a study on confidence is in progress about pulse source by switching device. An advanced company are studying to solve this problem. In this research, it is studied that each variables effecting motor reliability have correlation through experiment and more over forecasting the reliability of motor under inverter operation.

• Journal of Applied Reliability
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• v.16 no.3
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• pp.202-207
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• 2016

Purpose: The purpose of this study is main factors (environmental conditions, pattern spacing, pattern material) that effect the ion-migration of PCB. Methods: Recently, the electronic components are becoming more high density of electronic device, so that electronic circuits have smaller pitches between the patten and more vulnerable to insulation failure. so the reliability of electric insulation of device has become an ever important issue as device contact pitches of pattern. Usually, ion-migration occurs in high temperature and high humidity environment as voltage is applied to the circuit. Under high temperature and high humidity, voltage applied electronic components respond to applied voltages by metals's electrochemical ionization and a conducting filament forms between the anode and cathode across a nonmetallic medium. This leads to short-circuit failure of the electronic component. Results: we studied ion-migration that occurs in accordance with the main factors (environmental conditions, pitches, pattern material). The PCB pattern material was made by two different types of material (free solder, OSP) for this research and pitches of pattern is 0.15mm, 0.3mm, 0.5mm. PCB was experimented in the environmental conditions (high temperature $120^{\circ}C$, high temperature and high humidity $85^{\circ}C$, 85%RH) and was analyzed for ion-migration through the experiment results. Conclusion: We confirmed that environmental condition, pitches of pattern, pattern material had effect on ion-migration of PCB.

• Journal of Energy Engineering
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• v.1 no.1
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• pp.66-75
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• 1992

The performance of heat transfer through double pane window has been investigated using experimental and numerical methods. The range of the gap distance between glasses are 0.5-10 cm. The convection heat transfer plays the dominant role for the case of the wide gap distance together with the large Rayleigh number and thereby, reduces the enhanced thermal resistance due to the increased air gap, while the conduction heat transfer does the major role for the case of small gap distance. In order to enhance the thermal insulation of the double pane window, the heat transfer of triple pane window, which is constructed to put one more glass at the middle of the double pane, is investigated to check the reduction of the convection heat transfer together with the effect of the radiation shield due to the presence of the additional glass. Further, a spacer is installed at the middle height of the double pane, and the effect of which on the suppression of the convective heat transfer is analyzed carefully, using experimental and numerical methods. For the case of the spacer-installation, the amount of energy saving is considered about 10%, but the energy saving increases a lot to 30-50% for the case of triple pane window, due to the substantial radiation shield effect of the presence of the additional glass.

• Progress in Superconductivity and Cryogenics
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• v.17 no.1
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• pp.44-47
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• 2015

High voltage superconducting apparatuses have been developed presently around the world under AC and DC sources. In order to improve electrical reliability of superconducting apparatuses with AC and DC networks, a study on the DC as well as the AC electrical breakdown characteristics of cryogenic insulations should be conducted for developing a high voltage superconducting apparatus. Recently, a sub-cooled liquid nitrogen cooling system is known to be promising method for developing a high voltage superconducting apparatus. A sub-cooled liquid nitrogen cooling system uses gaseous nitrogen to control the pressure and enhance the dielectric characteristics. However, the dielectric characteristics of gaseous nitrogen are not enough to satisfy the grade of insulation for a high voltage superconducting apparatus. In this case, the application of solid insulating barriers is regarded as an effective method to reinforce the dielectric characteristics of a high voltage superconducting apparatus. In this paper, it is dealt with a barrier effect on the DC and AC dielectric characteristics of gaseous nitrogen with respect to the position and number of solid insulating barriers. As results, the DC and AC electrical breakdown characteristics by various barrier effects is verified.

• Korean Institute of Interior Design Journal
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• v.21 no.4
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• pp.114-120
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• 2012

There are lots of buildings which were built before the Legislation on building energy rating system. Remodeling of the buildings would be required for an improvement of the building energy rating system was enforced by the government. In the Passive Building Design, Elements which will be used for the remodeling are Insulation, Window, External venetian blind, Heat exchanger. The Purpose of this study is to indicate a Method for the improvement of Energy saving by an analysis of Construction Cost, Cost Evaluation, Energy performance Efficiency in applied design elements. In this study, the remodeling of existing public buildings to improve energy efficiency rating was applied to extract the elements of design-specific energy performance, efficiency, and the application of the designs that has been analyzed. The results were as follows: applying the design-specific cost-effective investment that represents the economy (investment efficiency/%) surveyed the average insulation(7.0%), triple glazed windows(10.1%), double glazed windows(12.1%), external shading(24.5%), and Heat(77.2%) were analyzed in order to be more efficient. Analysis of the basis of information on the existing public buildings to improve energy efficiency rating for the remodeling depending on driving conditions at a degree of individual difference. The main effect, however, depending on economic investment, design elements, heat exchangers, external awning, double glazed windows, triple glazed windows, insulation, is recommended as review of the order shall be determined.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1560-1565
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• 2011

The environmental pollution caused by green-house gases such as $CO_2$ and $SF_6$ has been becoming the main issue of industrial society. Many developed countries are making efforts to minimize the amount of $CO_2$ emission come from the operation of high voltage electrical apparatuses. As a part of these efforts, 180 countries signed the Kyoto Protocol in 1997 to cut back on their green-house gas emissions. Nowadays, the study on the development of dry air insulated switchgear (DAIS) which is known as an eco-friendly electrical apparatus is in progress. A DAIS is advantageous for minimizing the effect of impurities and enhancing the dielectric characteristics over an air insulated switchgear (AIS) by applying constant pressure to an enclosed cubicle. Therefore, a study on the electrical insulation performance of dry air as a gaseous insulation medium is conducted in this paper to substitute a gas insulated switchgear (GIS) for DAIS. As results, it is verified that the AC dielectric characteristics of dry air are similar to those of air and the lightning impulse dielectric characteristics of dry air are superior to those of air at 1bar pressure condition. However, dry air is of inferior dielectric characteristics to $SF_6$ at 4bar pressure condition. Finally, it is suggested that the internal pressure of DAIS should be over 4bar pressure to develop a high voltage switchgear which has similar electrical performance to a conventional GIS. Also, the empirical formulae on calculating the maximum electric field intensity at sparkover of dry air are deduced by experiments according to pressures. It is expected that these results are helpful to design and develop a high voltage electrical apparatus.