• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.17 no.4
• /
• pp.36-45
• /
• 2021

In this study, to improve the indoor thermal environment of the radiant floor heating system, a study was conducted on the temperature change characteristics and energy consumption according to the change of the indoor air set temperature, the supply hot water temperature and the outdoor temperature. As for the control method, the on/off control and the thermal difference proportional control method proposed through previous studies were applied. In addition, in consideration of field applicability, numerical analysis was performed for the case where the indoor air temperature sensor was affected by the wall temperature. As a result, it was found that the temperature difference proportional control method is more effective for thermal comfort and energy saving than on/off control.

• Journal of Institute of Convergence Technology
• /
• v.12 no.1
• /
• pp.25-30
• /
• 2022

도심항공교통은 다수의 전기추진 수직이착륙 항공기가 이착륙 가능한 버티포트가 필요하다. 빌딩풍은 고층건물 주변부에서 발생하는 강풍으로 항공기 이착륙과정에서 항공기의 비행 안전성을 크게 훼손시킬수 있다. 본 연구에서는 항공기 이착륙시 발생할 비행안정성 분석을 위하여 먼저 빌딩풍 주변의 유동특성을 분석하는 연구를 수행하였다. 유동해석은 상용CFD 소프트웨어인 SimericsMP를 사용하였으며, 난류 모델은 k-ε RNG 모델을 사용하였다. 해석방법의 타당성을 검증하기 위하여 CAARC 빌딩모델의 표면 압력 계산결과를 풍동시험 결과와 비교⋅검증하였다. 두 개의 고충빌딩이 있는 상황을 가정한 후, 빌딩풍이 빌딩 주변부의 속도분포 변화에 미치는 영향을 분석하였다. 두 개의 고층 건물 사이의 거리가 증가하는 경우 와들 사이의 상호작용이 감소하는 것을 확인했다. 향후 본 연구를 확장하여 다양한 형상의 고충건물이 밀집해 있는 도심지역에 대한 유동해석 연구를 진행하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.103-103
• /
• 2021

실험실에서의 파랑생성에 흔히 사용되는 피스톤형 조파장치는 수심에 따라 유속이 동일하게 생성된다는 제약이 있어 주로 천해파의 생성에 적합한 것으로 알려져 있다. 본 연구에서는 이러한 제약조건 없이 다양한 유속분포의 파형을 생성하는 수직 다열화된 조파장치가 개발되었다. 우선, 수심방향으로 이산화된 각 패들(paddle)의 스트로크에 대해 선형해석해가 유도되었다. 개발된 해석해는 패들의 수 및 유속분포에 따라 기존의 피스톤형 혹은 플랩형 조파장치 해석해로 근사함이 밝혀짐으로써 포괄적으로 활용될 수 있음이 확인되었다. 즉 개발된 해석해를 활용하면 선택적으로 피스톤형 및 플랩형 조파성능이 구현될 수 있다. 더불어 개발된 해석해는 다상유체의 내부파 생성에도 확정되어 적용가능함이 확인되었다. 다음으로, 개발된 조파장치를 수치적으로 구현하였다. 오픈소스 3차원 수치모형인 OpenFOAM 중, 두 개 이상의 불연속 및 비압축 유체에 대한 Navier-Stokes 방정식을 해결하는 수치 모듈을 사용하여 제안된 수직다열화된 조파장치의 성능이 평가되었다. 이때 동적격자모델(olaDyMFlow)을 결합함으로써 개발된 조파장치 움직임이 물리적 조파장치와 흡사하도록 수치적으로 구현하였다. 모의결과, 여러 개의 다열화된 패들이 층류 흐름 조건에서 심해파를 효율적으로 생성시키고, 중간수심 파랑조건에서는 제안된 조파장치가 상대적으로 덜 유리함을 확인할 수 있었다. 마지막으로 공기, 기름 및 물 등 3상의 흐름조건에서 단 두 개의 패들을 활용하여 각각 내부파 및 표면파를 생성하되었으며, 모의 결과는 해석해과 비교됨으로써 개발된 조파장치의 성능이 검증되었다.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.1
• /
• pp.73-84
• /
• 2018

Recently, the importance of flame retardation treatment technology has been emphasized due to the increase in urban fire accidents and fire damage incidents caused by building exterior materials. Particularly, in the utilization of wood-based building materials, the flame retarding treatment technology is more importantly evaluated. An Intumescent system is one of the non-halogen flame retardant treatment technologies and is a system that realizes flame retardancy through foaming and carbonization layer formation. To apply the Intumescent system, composite material was prepared by using Ethylene vinyl acetate (EVA) as a matrix. To enhance the flame retardant properties of the Intumescent system, a nano-clay was applied together. Composite materials with Intumescent system and nano - clay technology were processed into sheet - like test specimens, and then a new structure of cross laminated timber with improved flame retardant properties was fabricated. In the evaluation of combustion characteristics of composite materials using Intumescent system, it was confirmed that the maximum heat emission was reduced efficiently. Depending on the structure attached to the surface, the CLT had two stages of combustion. Also, it was confirmed that the maximum calorific value decreased significantly during the deep burning process. These characteristics are expected to have a delayed combustion diffusion effect in the combustion process of CLT. In order to improve the performance, the flame retardation treatment technique for the surface veneer and the optimization technique of the application of the composite material are required. It is expected that it will be possible to develop a CLT structure with improved fire characteristics.

• Analytical Science and Technology
• /
• v.20 no.4
• /
• pp.261-267
• /
• 2007

The 20 L small chamber test method is to evaluate pollutants such as TVOC, formaldehyde emitted from building materials. This method was only designed to evaluate the surface emission of sample exposed in the chamber. In this method, building materials cut with a fixed standard size are fixed in a sample sealing box. The sample sealing box is put into the 20 L test chamber. This chamber is ventilated at a standard air change rate with purified air for 7 days then the sample from the chamber is collected and analyzed to measure the emission rate of TVOC and formaldehyde. In this method, however, if the sealing box does not guarantee airtightness, accurate evaluation for the building materials can not be achieved due to the pollutants emitted from edge of the sample so called, edge effect. This edge effect can be much greater when evaluating panels such as plywood, flooring due to their surface treatment. In this study, flooring was tested to check airtightness of the sample sealing box with analytic results between 1L and 20 L test chamber. Furniture materials like LPM coated one side surface treatment and MDF coated both sides surface treatment with LPM were tested to identify whether the improvement of the sample sealing box airtightness is possible with the comparison between existing and improved test method that low VOC emission tape was used to seal the sample edge. After 7 days, MDF TVOC emission rate was different according to the existence and nonexistence of tape. The emission rate of the existing test method was $0.009mg/m^2h$ and that of improved test method was $0.003mg/m^2h$. Relative standard deviation for the existing test method was $0.004mg/m^2h$ and relative standard deviation for the improved test method was $0.002mg/m^2h$ when the same sample was analyzed three times. The improved test method in this study using low VOC emission tape was effective and able to reduce the heterogeneous effect of the edge from the sample sealing box.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.5
• /
• pp.16-26
• /
• 2004

As the importance of outdoor lighting become more widely recognized, outdoor lighting has been installed in many buildings, plazas, landscape, and historical monuments in Korea, Outdoor lighting on showing complex, in particular, express its values as local landmarks. However, the excessive outdoor lighting in the large-scale shopping complex tends to cause light pollution. Many advanced countries are trying to create a comfortable lighting environment by the guidlines and regulations on outdoor lighting to prevent light pollution. For this research backgrounds, the light pollution of three showing complexes in Seoul have been investigated. For the purpose, luminance of building facade, horizontal illuminance, and vertical illuminance were measured with proper measurement instruments and compared the results with the CIE recommendations. The results of the study are as follows. As no cut-off luminaries are currently installed on pedestrian walks, some glare were occured partially. It also shows that the luminance of building facades are high to improve the degree of public awareness of buildings and advertisements. In other words, the luminance of the building facade, when compared with that of the CIE recommendations, is twice as high and the vatical illuminance of pedestrian walks is far higher than that of the CIE recommendations, which proves the existence of light pollution. As Korea has not yet provided proper regulations or guidelines for the control of light pollution, it is necessary to make appropriate codes for it.

• Journal of Radiation Protection and Research
• /
• v.32 no.3
• /
• pp.97-104
• /
• 2007

The corelation between the indoor volume and the measured radon concentration has been analyzed by comparing the radon concentration and the indoor volume of apartment rooms in Jeonju City. We also measured the annual exposure dose based on the variation in indoor radon concentration over time. To do this, we took 8 larger rooms and 8 smaller rooms of apartment, respectively, as a sample. The average volume of the larger rooms and that of the smaller rooms were $31.59\;m^3$ and $16.82\;m^3$, respectively. The average radon concentration of the larger rooms and that of the smaller rooms turned out to be $71.73\;Bq/m^3$ and $108.51\;Eq/m^3$, respectively. indicating that indoor volume is in inverse proportion to the radon concentration, i.e., the bigger the ratio of the surface area/volume, the higher the indoor radon concentration. From the measurement of the variation in indoor radon concentration over time fur a single day, the average intraday radon concentration variation was found to be about $46.8\;Bq/m^3$. The highest level of concentration ($114.5\;Bq/m^3$) was measured between 8 and 10 AM and the lowest level of concentration ($67.7\;Bq/m^3$) between 2 and 4 PM. The annual exposure dose turned out to be in the range of 0.3 mSv/yr to 2.16 mSv/yr, showing that the dose in some apartments exceeded 1.3 mSv/yr, the numerical value presented by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR).

• Cartoon and Animation Studies
• /
• s.43
• /
• pp.185-209
• /
• 2016

Pattern refers to singular or repetitive decorative form in a blank surface, Also pattern is not just something to simply fill in the blanks, and has more meanings. Pattern reflects the specific culture or regional feature. So Depending on which pattern to use, creator can give particular of identity. which is generally utilized in visual arts such as painting, architecture, craft, as well as animation. Pattern in animation plays a role of decorating background or surfaces of characters' outfits or props. And Parttern is effective way to describe the story of the times and space environment of the background. Tomm Moore, an animation director in in Ireland mainly produces animations based on traditional folk stories or myths. He usually utilizes cultural and artistic factors related to the themes in his work production. One example is the insertion of pattern closely associated with the narratives and backgrounds of animations to create profound scenes. Tomm Moore used the Irish Celt pattern in Secret of Kells (2009) and Song of Sea (2014) and Islam geometric pattern and plant pattern in a short nimation named On Love from Kahlil Gibran's The Prophe (2014). This study attempts to examine the historical and cultural foundation and the narratives of these two animations, Song of Sea(2014) and Kahlil Gibran's The Prophet: On Love (2014) in which Tomm Moore participated as the director and producer, exploring their relevant traditional patterns. Moreover, it also attempts to analyze how these traditional patterns are utilized in the animations.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.28 no.3
• /
• pp.123-129
• /
• 2018

Ink-jet printing technology with ceramic ink of the four digital primary colors (cyan, magenta, yellow, and black; CMYK) can provide stable coloration even in the high-temperature firing process. Ceramic ink-jet printing can be widely applied in construction and ceramic industries due to the advantages of accurate and fast printing process of digital images for various products. Generally, organic solvent with proper viscosity and surface tension has been used in digital ink-jet printing process. However, the needs of ceramic ink without VOCs emission is increasing. In the present study, eco-friendly ceramic ink was synthesized by combining alumino boro-silicate glass frit and $CoAl_2O_4$ inorganic pigment based on an aqueous solvent that does not generate VOCs. The rheological properties and dispersion stability of aqueous ceramic ink were optimized. Jetting behavior and printing characteristics of the ceramic ink were also investigated in detail. As a result, the formulated aqueous ceramic complex ink showed a suitable jetting behavior without satellite drop by adjusting viscosity and surface tension. The ceramic ink can be printed on glass substrate with minimized spreading phenomena duo to high contact angle.

• Journal of the Korea Concrete Institute
• /
• v.14 no.4
• /
• pp.449-456
• /
• 2002

Recently, the application of high strength and high performance concrete has been gradually increased as an important construction material for high rise and huge scaled construction. However, high performance concrete has undesirable characteristics of spalling subjected to high temperature due to its dense microstructure content. A spalling by fire brings surface failure and falling off concrete member. It is considered that spalling by fire should be taken into account for the safety of the concrete structure under fire. Therefore, in this paper, tests are carried out using high performance concrete containing polypropylene(PP) fiber in order to improve the fire resistance performance. PP fiber contents and member sizes are varied. According to experimental results, as for the influence of PP fiber contents, all the test specimens without PP fiber show entire failure in W/C of 35％, while they show nearly sound shape except some kinds of surface fracture in W/C of 55％. When PP fiber is contained more than 0.07％, favorable prevention effects of spatting by fire are obtained. As for the effects of test specimens size, it tends to increase the possibilities of spatting by fire as test specimens become larger. And spatting by fire at the edge of test specimens occurs more frequently than at the surface of test specimens. Residual compressive and tensile strength shows 45∼65 ％ of its original strength at W/C of 35％, and 30∼40％ at W/C of 55 ％.