• Title/Summary/Keyword: RAE

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Numerical Simulation for Transonic Wing-Body Configuration using CFD (CFD를 이용한 천음속 날개-동체 형상 해석)

  • Kim, Younghwa;Kang, Eunji;Ahn, Hyokeun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.3
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    • pp.233-240
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    • 2017
  • The flowfield around transonic wing-body configuration was simulated using in-house CFD code and compared with the experimental data to understand the influence of several features of CFD(Computational Fluid Dynamics) ; grid dependency, turbulence models, spatial discretization, and viscosity. The wing-body configuration consists of a simple planform RAE Wing 'A' with an RAE 101 airfoil section and an axisymmetric body. The in-house CFD code is a compressible Euler/Navier-Stokes solver based on unstructured grid. For the turbulence model, the $k-{\omega}$ model, the Spalart-Allmaras model, and the $k-{\omega}$ SST model were applied. For the spatial discretization method, the central differencing scheme with Jameson's artificial viscosity and Roe's upwind differencing scheme were applied. The results calculated were generally in good agreement with experimental data. However, it was shown that the pressure distribution and shock-wave position were slightly affected by the turbulence models and the spatial discretization methods. It was known that the turbulent viscous effect should be considered in order to predict the accurate shock wave position.

A Study of the Ceremonial Costume of the Crown Prince in the Year 1882 - Focusing on the Myeon-Bok (Royal Robe) - (임오(1882)년 가례 왕세자 복식연구(1) - 면복을 중심으로 -)

  • An, Ae-Young;Park, Sung-Sil
    • Journal of the Korean Society of Costume
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    • v.59 no.10
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    • pp.68-84
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    • 2009
  • A state wedding ceremony of kings and crown princes in the Chosun Dynasty was systemically formalized in a book Five National Ceremonies (1474) as one of the five major formal events of the royal auspicious ceremonies(Ga-rae). For a state wedding, Ga-rae Protocol was made by a devision for Ga-rae temporarily established for the occasion. A total number of auspicious ceremony protocols of kings and crown princes amounts to 20 in the span of 279 years. Among the proposals, the wedding of Soon-jong in the Imo Year of 1882 is described most thoroughly. Nap-bin-ui(reception of bride) comprises six rituals which are nap-chae, nap-jing, go-gyi, chaek-bin, chin-young, and dong-ryae. A grand formal costume of the crown prince is granted based on the 'Seven Parts Formal Costume' of the first year of the king Moon-jong in 1450 together with an official costume for crown prince(Gon-myeon-chil-jang) arranged in the third year of the king Young-rak. In the royal palace of the Chosun Dynasty, the granted formal costume of the crown prince is officially recorded as a code and presented in a Gwon-ji-il section of the Formalities of the Five National Ceremonies. The formal costume and its accessory set for the crown prince recorded as a code are described in Sangbang Jeong-ryae as the formal costume of the crown prince section published by the king's request at the high senate commission in the 28th year of the king Young-jo in 1752. The aim of the study is to investigate the formal costume of the crown prince as an auspicious ceremonial costume worn at the wedding in the year of Imo.

Aerodynamic Shape Optimization Using a Continuous Adjoint Formulation on Unstructured Meshes (비정렬 격자계에서 Continuous Adjoint 방정식을 이용한 공력 형상 최적 설계)

  • Lee, Sang-Wook;Kwon, Oh-Joon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.4
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    • pp.18-27
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    • 2002
  • Aerodynamic shape optimization of two-dimensional airfoils in inviscid compressible flows is performed using a continuous adjoint formulation on unstructured meshes. Accurate evaluation of the gradient is achieved by using a reconstruction scheme based on the Laplacian averaging. A least-square method with extended stencil is used for flow gradient calculations. Proper convergence criterion is studied on Euler and adjoint equations for efficient design. The present method has been applied to RAE2822 and NACA0012 airfoils such that wave drag can be minimized by removing the shock wave. An inverse design is also performed to recover the shock wave on the designed RAE2822 airfoil.

Predicting Factors Affecting Clinical Outcomes for Saccular Aneurysms of Posterior Inferior Cerebellar Artery with Subarachnoid Hemorrhage

  • Hong, Young-Ho;Kim, Chang-Hyun;Che, Gil-Sung;Lee, Sang-Hoon;Ghang, Chang-Gu;Choi, Yu-Seok
    • Journal of Korean Neurosurgical Society
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    • v.50 no.4
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    • pp.327-331
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    • 2011
  • Objective : The aim of this study is to investigate the clinical outcomes of surgery and coiling and analyze the predicting factors affecting the clinical outcomes of ruptured posterior inferior cerebellar artery (PICA) aneurysms. Methods : During the last 15 years, 20 consecutive patients with ruptured PICA aneurysms were treated and these patients were included in this study. The Fisher's exact test was used for the statistical significance of Glasgow Outcome Scale (GOS) according to initial Hunt-Hess (H-H) grade, treatment modalities, and the presence of acute hydrocephalus. Results : Eleven (55%) and nine (45%) patients were treated with surgical clipping and endovascular treatment, respectively. Among 20 patients, thirteen (65.0%) patients had good outcomes (GOS 4 or 5). There was the statistical significance between initial poor H-H grade, the presence of acute hydrocephalus and poor GOS. Conclusion : In our study, we suggest that initial H-H grade and the presence of acute hydrocephalus may affect the clinical outcome rather than treatment modalities in the ruptured PICA aneurysms.

Laboratory Evaluation of the Accuracy, Precision, and Inter-instrumental Variance of a Portable Photoionization Detector (휴대용 광이온화 검출기의 정확도, 정밀도 및 기기간 차이에 대한 실험실 평가)

  • Choi, Dongmin;Choi, Youngeun;Yoon, Chungsik;Rhie, Kwangwon;Lee, Yunkeun;Lee, Ikmo;Park, Jeongim
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.22 no.3
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    • pp.200-208
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    • 2012
  • Objectives: This study investigated the performance of three separate units of a portable photoionization detector (PID, ppb-RAE 3000) for measuring volatile organic compounds (VOCs) in a laboratory. Methods: A laboratory evaluation of the accuracy, precision, and inter-instrumental variance of three separate units of a portable PID (ppb-RAE 3000) was performed. The evaluation was based on the preparation of a test air sample of known toluene or ethylacetate concentration in a Tedlar$^{(R)}$ bag. The test air sample was monitored and data were logged consecutively by the three PIDs. A certified gas of 50 ppm toluene was also monitored during the test to ensure the reliability of the generated test air sample. Four different concentrations ranging from 0.1 to 2 TLV were used and a series of five measurements for each concentration level was performed. The accuracy was evaluated using National Institute for Occupational Safety and Health (NIOSH) criteria. Results: The results from the oldest ppb-RAE3000 unit among the three test units generally fell outside the NIOSH recommended accuracy criteria of ${\pm}25%$, whereas the other two units produced results which were acceptable at, or greater than, 25 ppm of toluene, or 0.5 TLV. These units also met the NIOSH criteria for some ethylacetate measurements but the results were not consistent. Conclusions: Considering the inconsistent performance of these ppb-RAE 3000 units, this device may not be appropriate for use as an alternative to the standard measurement methods. However, it can serve good survey instruments to identify exposure sources or concentration profiles. For all applications, the ppb-RAE 3000 should be used with frequent calibration checks, additional validation using a reference material, and careful maintenance.

Recipe Standardization and Nutrient Analysis of 'Dong-rae Pajeon' (Local Food in Busan) (부산 향토음식 동래파전의 조리표준화 및 영양분석)

  • Kim, Sang-Ae;Shin, Eun-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.11
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    • pp.1472-1481
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    • 2007
  • The purposes of the study were to find refined taste of ancestor through historical research about traditional cooking method and ingredient for the purpose of enriching today#s dietary life and to hand down a particular style of regional dish and excellence of nutritional aspect by providing a standard recipe and nutrition analysis data on #Dong-rae Pajeon#. To collect data about traditional ingredients and cooking method, researcher interviewed seven local natives who have kept a traditional food costumes, visited four restaurants, and reviewed ten cookbooks. The interviewees recalled and demonstrated the cooking procedure. The standard recipe of #Dong-rae Pajeon# was created after three experimental cookings, based on the recipes of the natives, restaurants, and cookbooks. According to the natives# statements, #Dong-rae Pajeon# was a special dish that was offered to the king at #Samzi-nal# (March 3rd of the lunar calendar). It was also a seasonal (before cherry blooming time) and memorial service dish of the province#s high society. The main ingredients were small green onion, dropwort, beef, seafood (large clam, mussel, clam meat, oyster, shrimp, fresh water conch), waxy rice powder, non-wax rice powder, and sesame oil which were abundant in Busan and Kijang region. Energy per 100 g of #Dong-rae Pajeon# was 148 kcal. Protein, lipid, fiber, Ca, and Fe contents were 8.8 g, 2.0 g, 8.6 g, 57.7 mg, and 1.8 mg respectively. Contents of cystine, lysine, leucine, valine, isoleucine which are essential amino acids were high in #Dong-rae Pajeon#. Fatty acids contents are oleic acid (20.5%), linoleic acid (20.1%) and linolenic acid (10.4%) while P/M/S ratio was 0.73/0.67/1.