Experimental Study on the Spread Characteristics of Initial Fires According to Corridor Types

Kweon,Oh Sang,Kang,Hyun,Kim,Heung-Youl 한국방재학회 2021 한국방재학회논문집 Vol.21 No.4

건축물에서 화재 발생 시 복도는 화염과 연기의 확산 통로가 되어 재실자가 위험에 노출될 수 있다. 따라서 본 연구에서는 복도의 형태에 따른 화재의 특성을 분석하기 위해서 단방향 피난이 가능한 ‘L’ 형태와 양방향 피난이 가능한 ‘T’ 형태의 복도를 2.4(L) × 10(W) × 2 .4(H) m 크기로 제작하여 실물화재 실험을 진행하였다. 실물화재 실험은 2.0(W) × 1 .8(H) m 크기의 단일 개구부를 가지고 있는 2.4( L) × 3 .6(W) × 2 .4(H) m의 화재실에서 진행되었으며, 화재실 내부의 가연물은 ‘L’ 형태에서는 열방출률이 651.4 kW인 목재크립을 사용하고 ‘T’ 형태에서는 95.7 kW인 의자를 사용하였다. 실물화재 실험에서는 복도 내부의 온도 변화를 측정하였고 이른 통해 측정된 온도의 평균 최대값은 ‘L’ 형태에서 432.1 ℃로 ‘T’ 형태에서는 103.5 ℃로 나타났다. 또한, 실물화재 실험의 결과와 복도의 형태에 따른 환기특성을 BFD 곡선식에 적용하여 복도의 형태에 따른 화재성장 모델의 설계 과정을 제시하였다. During an accidental fire in buildings, the corridor becomes the path for flame and smoke to spread, exposing the occupants to danger. Therefore, this study conducted real-scale fire experiments using corridors of size 2.4(L) × 10(W) × 2.4(H) m an “L-type” corridor for one-way evacuation and a “T-type” corridor for two-way evacuation to analyze the characteristics of fire according to the shape of corridors. The real-scale fire experiments were conducted in a fire room (2.4(L) × 3.6(W) × 2.4(H) m) with a single opening (2.0(W) × 1.8(H) m). The combustibles used inside the fire room were wood cribs, with a heat release rate of 651.4 kW, in the L-type corridor and chairs, with a heat release rate of 95.7 kW, in the T-type corridor. The temperature inside the corridor was measured during the real-scale fire experiments, and the average maximum measured temperature was 432.1 °C in the L-type corridor and 103.5 °C in the T-type corridor. The experimental results and the ventilation characteristics according to the corridor types were applied to BFD curves to show the process of designing fire growth models according to corridor types.

복합시술 모발의 자외선 보호처리에 따른 손상도와 색상 변화

라채숙ㆍ권수애ㆍ이옥규(hae Suk LaㆍSoo Ae KweonㆍOk Kyu Lee) 한국인체미용예술학회 2016 한국인체미용예술학회지 Vol.17 No.1

This study aimed to determine the effects of UV-blocking by the type of UV care agent for complex-treated hair. For this, healthy women’s hair was permed, bleached and dyed, and a Polypeptide Protein Treatment and hair sunscreen agent were applied. After that, changes in the degree of wave formation, hair surface conditions, physical properties of the hair and hair hue were examined by irradiating UVB rays. The analysis results were found as follows: In terms of the degree of wave formation, no difference was observed among UV care agents. In terms of hair surface scale, hair damage was lower when the hair was coated twice as opposed to being coated once regardless of the type of the UV care agent and treatment method. In addition, tensile strength, elongation rate and resilience rate were superior in the hair recoated with the hair sunscreen agent. In contrast, no significant difference was observed among the UV care agents in terms of damage rates. Lightness and reflected light were also high in the hair recoated with the hair sunscreen agent. In addition, the a* value, reflection and dominant wavelength were the highest in the hair with post-treatment coating for the skin while b* value, reflection and degree of irritation was the highest in the hair with post-treatment coating for hair. The said results can be summarized as follows: The UV care agent revealed effective UV-blocking effects by maintaining the wave formation and preventing hair damage. When UV rays were irradiated, the hair for post-treatment product was the most efficient in maintaining hair color.

Experimental study on the method of estimating the vertical design wave force acting on a submerged dual horizontal plate

Kweon, Hyuck-Min,Oh, Sang-Ho,Choi, Young-Hwan The Society of Naval Architects of Korea 2013 International Journal of Naval Architecture and Oc Vol.5 No.4

A steel-type breakwater that uses a submerged dual horizontal porous plate was originally proposed by Kweon et al. (2005), and its hydrodynamic characteristics and design methodology were investigated in a series of subsequent researches. In particular, Kweon et al. (2011) proposed a method of estimating the vertical uplift force that acts on the horizontal plate, applicable to the design of the pile uplift drag force. However, the difference between the method proposed by Kweon et al. (2011), and the wave force measured at a different time without a phase difference, have not yet been clearly analyzed. In this study, such difference according to the method of estimating the wave force was analyzed, by measuring the wave pressure acting on a breakwater model. The hydraulic model test was conducted in a two-dimensional wave flume of 60.0 m length, 1.5 m height and 1.0 m width. The steepness range of the selected waves is 0.01~0.03, with regular and random signals. 20 pressure gauges were used for the measurement. The analysis results showed that the wave force estimate in the method of Kweon et al. (2011) was smaller than the wave force calculated from the maximum pressure at individual points, under a random wave action. Meanwhile, the method of Goda (1974) that was applied to the horizontal plate produced a smaller wave force, than the method of Kweon et al. (2011). The method of Kweon (2011) was already verified in the real sea test of Kweon et al. (2012), where the safety factor of the pile uplift force was found to be greater than 2.0. Based on these results, it was concluded that the method of estimating the wave force by Kweon et al. (2011) can be satisfactorily used for estimating the uplift force of a pile.

마루높이 設定 基準을 위한 기대월파확률 추정 Scenario

권혁민(kweon Hyuck Min),김건오(Kim Gun Oh) 대한토목학회 2009 대한토목학회논문집 B Vol.29 No.4B

조위발생빈도분포가 상이한 우리나라 해역에 위치한 해안구조물의 마루높이를 설정하는 문제에 있어서 조위의 합리적인 취급이 중요하다. 권혁민 등(2005, 2006)은 해역별 기대월파확률 계산결과로서 조위발생빈도분포의 편차가 크면 클수록 작아지는 경향이 명백함을 보였다. 이는 년 단위 조위의 발생빈도분포가 년 최대파고 급의 파 발생빈도분포와 년 중 언제든 조우할 수 있다는 가정을 내포하고 있다. 본 연구에서는 파와 조위의 조우 가능성을 년 최대 파급의 파가 발생할 수 있는 여름철 또는 겨울철을 대상으로 계절별 일 최대 조위발생빈도분포를 불확정요소로 취급하여 계산했다. 계산결과, 우리나라 전 해역의 기대월파확률이 1%미만으로 수렴됨이 확인되어 이를 시나리오로 제안하고자 한다. 본 시나리오에 의하면 기대월파확률이 동일하도록 마루높이의 설정이 우리나라 전 해역을 대상으로 가능함을 확인하였다. 본 연구에서 마루높이는 전 해역에 대하여 계절별 일 최대조위의 평균값으로부터 설정이 기능한 것으로 추정된다. The importance of resonable treatment of tide characteristics has been shown by Kweon, et al. (2005, 2006) for the crest elevation estimation because of a big difference of tidal elevation along Korean coast. For the procedure of crest elevation design, the expected overtopping probability (EOP) was estimated by Kweon, et al. (2006). The comparisons on each sea showed that EOP was lower east, south and west sea in order. The results involved the assumption that the tide and design level wave height meet any time in a year. However, big waves mainly occur in summer or winter in Korean coast, the study focuses on the encounter probability of big waves and seasonal tide level. A theory of the encounter probability is not derived by the present study but it shows reasonable acceptability of the proposed scenario in which the expected overtopping probability could be an index for the crest elevation estimation in Korean coast. The calculation based on the scenario gives the possibility range for the crest elevation estimation which has no tendency of each sea along Korean peninsular. The range is within the expected overtopping probability of 1% in the whole coast of Korea.

신뢰성 해석에 의한 우리나라 해역별 기대월파확률 특성 비교

권혁민(Kweon Hyuck Min),박현석(Park Hyun Suck),안경모(Ahn Kyungmo),천세현(Cheon Se Hyeon) 대한토목학회 2006 대한토목학회논문집 B Vol.26 No.4B

권혁민 등(2004)은 우리나라 동해안의 실해역 극치파고 및 조위발생빈도분포를 고려한 기대월파확률 산정기법을 제안했다. 권 등의 연구는 동해안의 묵호와 부산지역을 비교하여 조위발생빈도분포가 기대월파확률에 크게 영향을 준다는 것을 예시했으며 그 분포의 표준편차가 크면 클수록 기대월파확률이 작아짐을 보였다. 본 연구는 권혁민 등이 제안한 기대월파확률 계산방법을 준용하여 우리나라 동ㆍ남ㆍ서 해역의 기대월파확률 특성에 대하여 현행 설계방법에 의해 결정된 마루높이에 대한 평가를 시도하였다. 본 연구결과, 개략적으로 동ㆍ남ㆍ서 해역으로 갈수록 기대월파확률이 작아짐을 알 수 있다. Kweon et al. (2004) proposed the calculation method of Expected Overtopping Probability (EOP) that considers the occurrence frequency distribution of real sea tide. The method was applied for the comparison of the EOP of Mukho and Susan sea. They showed that the tide occurrence frequency had a great effect on the EOP and the value becomes smaller as the standard deviation of the frequency comes bigger. The present study following Kweon et al.'s method estimates the EOP characteristic of the crest elevation located on East, South, and West sea. The study shows that the EOP becomes smaller following East, South, West sea in order.

Protection of superficial organs using bismuth and iodine shielding during computed tomography in phantoms

Kweon Dae Cheol,Lee Jong-Woong,Choi Jiwon 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.1

We sought to minimize streak artifacts caused by beam hardening on chest CT scan, obtain high-quality CT images and compare image quality and dose between with and without iodine and bismuth shielding material to protect superficial organs. During CT, the radiation dose was measured and the images evaluated before using the shielding material, iodine and bismuth. A body phantom of polymethyl methacrylate (PMMA) measuring 32 cm was used for image quality and radiation dose measurement according to the shielding material of the CT scan. During CT, phantom noise was measured to be 11.49 HU without shielding, 12.95 HU with bismuth, and 14.67 HU with iodine (p > 0.05). Based on the dose, in the absence of the shielding material, the shielding with iodine showed a dose reduction effect of 40.64% at 11 o'clock and 35.74% at 1 o'clock. In the case of bismuth shielding, the dose at 11 o'clock was decreased to 34.06% and the dose at 1 o'clock was decreased to 34.32%. Dose reduction was observed prior to the use of the shielding material and the application of the iodine and bismuth shielding materials (p < 0.05). In phantom chest CT, the dose reduction of the superficial organs using iodine and bismuth, a radiation shielding material, was confirmed.

Study of Metabolic Syndrome with the Drosophila Model System : sNPF Regulates Insulin Signaling

Kweon Yu 한국동물생명공학회(구 한국동물번식학회) 2008 Reproductive & developmental biology Vol.32 No.2

ON SEQUENTIAL HAUSDORFF COMPACTIFICATION SATISFYING THE FIRST AXIOM OF COUNTABILITY

Kweon, Seon-Hee,Hong, Woo-Chorl The Youngnam Mathematical Society Korea 1992 East Asian mathematical journal Vol.7 No.2

Radiation effect on peri-implant tissue after implantation

Kweon, Hyeog-Sin,Song, Kwang-Yeob The Korean Academy of Prosthodonitics 2000 대한치과보철학회지 Vol.38 No.3

Statement of problem. There were several studies on the effects of irradiation to peri-implant bone tissue. However, no clear biological effect of irradiation on peri-implant bone tissue was reported yet. Purpose. This study compared the effect of irradiation on the surrounding tissue of a HA-coated implant fixture with controls. Material and methods. 6 Steri-Oss implants were implanted into the femur of 6 mongrels. The implanted dogs were divided into three groups and received irradiation. After 1 month, 2months and 4 months healing period, the histologic examination and mobility test and digital radiographic imaging analyses were performed to compare the control and experimental group respectively. Results. The irradiated group showed slower healing than control group in light microscopic observations. The mobility test demonstrated significant less number (Periotest) in control group than that of irradiated groups. The digital radiographic imaging analysis showed that the bone density of irradiated group was higher than control group. Conclusion. Generally, control group showed favorable biological response and less mobility than irradiated group. The conflict result of bone density value were measured by the digital radiographic imaging analysis. The digital radiographic imaging analysis needs more research in future.

Study of Metabolic Syndrome with the Drosophila Model System : sNPF Regulates Insulin Signaling

Kweon Yu 한국동물번식학회 2008 Reproductive & Developmental Biology(Supplement) Vol.32 No.2s