• 조명전기설비학회논문지
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• 제26권2호
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• pp.27-33
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• 2012

In this paper, we researched the heat transfer analysis of 1.2[kW] BLDC motor on the condition of the external flow. The BLDC motor is fallen under influence of some heat generated by rotationg motor speed and it changes the life and confidence of motor. The heat makes to reduce the life of insulation and the magnetization. So motor can't make own performance. Therefore we calculated the losses about number of revolutions of motor. And then, we analyzed the heat transfer of BLDC motor by using the results when a fan attached to motor makes the external flow or not. The results showed that the temperature of motor increased constant values irrespective of external air temperature. The temperature of motor decreased very lower values than prior researches when the fan makes the external flow. In this method we can analyze the performance, losses and heat transfer of motor applied in the many industries.

• Archives of Plastic Surgery
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• 제32권6호
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• pp.753-756
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• 2005

In the cases of severe arrythmia and conduction failure, a permanent implanted pacemaker is considered an essential treatment modality with less complication rate, broad indications and low morbidity. However, some pacemakers needs to be removed or replaced due to infection, in need of a lead upgrade, elective replacement, conduction failure or insulation failure. The most common indication for pacemaker extraction is infection. Conservative treatments such as administration of intravenous antibiotics and limitation of debridement are not effective and the removal of the entire pacing system is considered to be the best approach to pacemaker pocket infection. Although a locking stylet, a laser sheath and other newer methods of transvenous lead extraction have been proven to be effective, all leads cannot be removed. Moreover, major complications such as, cardiac tamponade and respiratory arrest during leads extraction procedure should not be ignored. We experienced two cases of exposed pacemakers in the subclavicular region. After removing the pacemaker body, exposed proximal lead was pulled out and cut off. The end of remnant external insulation tube was tied to prevent infection propagation between external insulation tube and inner metalic coil. Wounds were covered by local flap coverage. No other problems were detected during the one-year follow-up. Since there are few reports on lead-preserving method of treating limited infection of exposed pacemakers, we would like to present our new method for treating exposed pacemakers.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.66-69
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• 2017

The internal temperature of human-tissue transfers must be steadily maintained regardless of the external environmental changes. An ice pack and dry ice are the coolants for the transfer containers for which heat-insulating materials such as EPP (expended polypeopylene and EPS (expended polystrene) are used; however, changes of the external temperature/pressure and the melting of the coolants that is due to a long carriage result in changes of the internal temperature, and this makes it difficult to maintain the temperature. Accordingly, the thermoelectric element was used to design/manufacture a transfer container to maintain the internal temperature regardless of the external environmental changes. As a result of the measurement of the changes of the internal temperatures of the manufactured thermoelectric-element container and the EPS container over time, the internal temperature of the EPS container was increased, whereas the internal temperature of the thermoelectric-element container was maintained. The temperature of the distilled water that was poured into the containers indicated a pattern identical to that of the internal temperature.

• 한국주거학회논문집
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• 제12권3호
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• pp.133-140
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• 2001

This study investigated the heat transmission coefficient through the experiment that the skylight, slope window of 60 degree and 30 degree consisted of pair glass and the double window of external window and internal window paper were suitable for heat insulation. As the result of experiment, the heat transmission coefficient of slope window was 1.06 times in the 60 degree, 1.18 times in the 30 degree and 1.31 times in the skylight as a standard lateral window. The heat transmission coefficient in the double window of external window and internal window paper was 3.017$\textrm{㎉}$/$\textrm{m}^2$.hr.$^{\cire}C$. The slope window was not suitable for the prescription by the increase of the heat transmission coefficient, so the user must pay attention to the treatment. This study investigated only the slope window of 12mm and 16mm pair glass and the double window of external window and internal window paper, study on the various pattern of window must be achived in a future.

• 한국생활환경학회지
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• 제21권6호
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• pp.959-964
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• 2014

Energy performance of building envelope components, including external walls, floors, roofs, windows and doors, is crutial for determining how much energy is required for heating and cooling in a building. Among various building technologies, a green roof system can be a good option for reducing heat gain and loss in new buildings as well as existing buildings for green remodeling. This paper evaluates the performance of green roof systems according to soil depth and Leaf Area Index (LAI) for existing buildings. It also attempts to quantify the energy saving effects on new and existing buildings with different insulation levels. Thermal performance of green roofs is mainly dependent on soil thickness and LAI. Installation of green roofs in deteriorated existing buildings can lead to improvements in roof insulation, due to the soil layer. An increase in soil depth leads to a decrease in heating load, regardless of conditions of vegetation on the green roof. Larger LAI values may reduce cooling loads in the cooling season. Installation of green roof in deteriorated existing buildings showed bigger energy saving effect in comparison to a case in new buildings. A simulation study showed that the installation of green roof systems in deteriorated existing buildings with low insulation levels, due to low thermal performance requirements when constructed, could improve the energy performance of the buildings similar or better to the peformance on new buildings with the most updated insulation standard. Thus, when remodeling a deteriorated building, green roofs could be a good option to meet the most recent energy requirements.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.524-531
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• 2011

The cryogenic vessel, storing a liquified solutions as LOX and $LN_2$, consists of a external vessel, internal vessel, thermal insulator and internal support. The internal support should be satisfied with mechanical strength not only to support weight of internal tank but also to maintain uniform space between external and internal tank in spite of external mechanical shock. However, excessive structure design of internal supports is able to increase the amount of heat conduction and the rate of vaporization. The thermal insulator, filled with space between a external and internal vessel, reduces the rate of heat transfer and guarantees the standing time of cryogenic vessel. Especially powder type of insulator has low thermal conductivity and reduce the specification of structure design. In order to evaluate the effect of insulator on structure design, the experiment set-up simulated cryogenic vessel was tested in shock environment according to thermal insulator. As a result, the behavior of internal support under external shock was understood and the design criteria was able to be suggested.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1346-1354
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• 2018

Quality of the power system depends upon the reliability of its components such as transformer, transmission lines, insulators, circuit breakers and isolators. The transient voltage due to internal or external reasons may affect the insulation level of the components. The insulation level of these components must be tested against these conditions. Different studies, testing of different electrical components against high voltage impulses and different industrial applications rely on the international manufactures for pulsed power generation and testing, that is quite expensive and large in size. In this paper a model of impulse voltage generator with capacitive load of pin type insulator is studied by simulation method and by an experimental setup. A ten stage high voltage impulse generator (HVIG) is designed and implemented for different applications. In this proposed model, the cost has been reduced by using small and cheap capacitors as an alternative for large and expensive ones while achieving the same effectiveness. Effect of the distributed capacitance in each stage is analyzed to prove the effectiveness of the model. Different values of front and tail resistances have been used to get IEC standard waveforms. Results reveal the effectiveness at reduced cost of the proposed model.

• International Journal of Concrete Structures and Materials
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• 제2권1호
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• pp.49-55
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• 2008

The disadvantage of PMM's (polymer-modified mortars) that are currently on the market is the utilization of expensive polymer additives and also the cost of the other components. One of the possibilities how to decrease this price is the effective utilization of waste materials which are very inexpensive in spite of their good properties. The combinations of different degree in polymer adhesiveness and waste secondary raw materials - fly ash - are experimentally verified in the paper. The use of fly ash in adhesive materials for ceramic tiles is limited by unsatisfactory initial adhesiveness to sintered ceramic sherd as a result of a running pozzolanic reaction that lowers the efficiency of polymer additives. On the other hand, the use of adhesive and backfill coating materials for gluing ETICS board insulation materials has brought very good results.

• 설비공학논문집
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• 제29권1호
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• pp.21-28
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• 2017

Curtain-wall systems have been widely applied to buildings because of their lightweight and constructability characteristics. However, as curtain-wall systems include many building materials, vapor barriers can become damaged and condensation can occur. Due to the material properties of stone curtain-walls, the external appearance and structure of a building could be damaged and the insulating performance of the curtain-wall could be worse. Natural ventilation using an air cavity in a curtain-wall is expected to be effective for the prevention of condensation in inner walls and for the reduction of building cooling energy use in the summer. The purpose of this experimental study is to analyze the influence of a ventilated cavity on the insulating performance of a curtain-wall and the ventilated cavity depth and ratio of top opening needed to prevent condensation in a curtain-wall.

• 조명전기설비학회논문지
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• 제30권1호
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• pp.44-48
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• 2016

In this paper, we analyzed the operating characteristics of a ventilating fan due to overload and overheating. The experiment assumed the forcible restraint of the blade due to external objects and the aging process. We analyzed the experimental temperature and operating characteristics of the three places in the interior of the ventilating fan. As a result of the analysis, the temperature distribution was highest to lowest in the following order: the thermal fuse, the motor inside, and the above winding. There was smell of burning enamel in the restraint experiment. Following the thermal fuse operation, the insulation of motor winding was good. In the case of rated voltage and new ventilating fan restrained for about 4hours, and the results of restraint experiments in the presence or absence of the thermal fuse, no risk of deformation or fire due to overheating was identified. Henceforward, ignition hazard experiments will be required for additional factors of aging, pollution, and defective insulation.