• Wind and Structures
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• 제38권3호
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• pp.193-202
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• 2024

Modern high-rise tower designs incorporating recessed balcony cavity spaces can be prone to high-frequency and narrow-band Rossiter aerodynamic excitations under glancing incident winds that can harmonize and compete with recessed balcony volume acoustic Helmholtz modes and facade elastic responses. Resulting resonant inertial wind loading to balcony facades responding to these excitations is additive to the peak design wind pressures currently allowed for in wind codes and can present as excessive facade vibrations and sub-audible throbbing in the serviceability range of wind speeds. This paper presents a methodology to determine Cavity Amplification Factors to account for façade resonant inertial wind loads resulting from balcony cavity aero-acoustic-elastic resonances by drawing upon field observations and the results of full-scale monitoring and model-scale wind tunnel tests. Recessed balcony cavities with single orifice type openings and located within curved façade tower geometries appear particularly prone. A Cavity Amplification Factor of 1.8 is calculated in one example representing almost a doubling of local façade design wind pressures. Balcony façade and tower design recommendations to mitigate wind induced aero-acoustic-elastic resonances are provided.

• 한국대기환경학회지
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• 제9권4호
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• pp.295-302
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• 1993

The nature of the cavity region and dispersion around trianglular ridge was investigated using model. The artifical neutral boundary layer was simulated in water channel. Two dimensional trianglar ridges, having height of 1.2 cm and various width were placed normal to the flow. Mean velocity with many dimensionless parameters were measured and compared with wind tunnel results by other studies. Using vorticity generator and roughness, the neutral boundary layer was well represented by the water channel. concentration patterns resulting from dye source placed 0.2 cm height above were examined. Narrower the trianglar ridge width resulted in increased amplification factor and the larges amplification factor was observed near downward top of the ridge.

• International Journal of Aeronautical and Space Sciences
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• 제7권2호
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• pp.26-32
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• 2006

This paper targets a direct and quantitative prediction of characteristics of unstable waves in a combustion chamber, which employs the governing equations derived in terms of amplification factors of flow variables. A freshly formulated nonlinear acoustic equation is obtained and the analysis of unsteady waves in a rocket engine is attempted. In the present formalism, perturbation method decomposes the variables into time-averaged part that can be obtained easily and accurately and time-varying part which is assumed to be harmonic. Excluding the use of conventional spatially sinusoidal eigenfunctions, a direct numerical solution of wave equation replaces the initial spatial distribution of standing waves and forms the nonlinear space-averaged terms. Amplification factor is also calculated independently by the time rate of changes of fluctuating variables, and is no longer an explicit function for compulsory representation. Employing only the numerical computation, major assumptions inevitably inherent, and in erroneous manner, in up to date analytical methods could be avoided. With two definitions of amplification factor, 1-D stable wave and 3-D unstable wave are examined, and clearly demonstrated the potentiality of a suggested theoretical-numerical method of combustion instability.

• Journal of Chest Surgery
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• 제43권6호
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• pp.588-595
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• 2010

배경: 종양의 종류에 따라 발현되는 종양 항원의 종류도 다양하며 그 발현률의 차이는 더욱 다양하다. 이와 같은 이유로 폐암의 치료연구를 위해서는 인체를 대신할 만한 동물 모형이 절대 필요하다. 저자는 편평상피세포암의 세포주를 배양하여 Nude mice의 흉강 내에 주입하는 방법으로 종양형성을 시도하여 종양형성의 성공 유무와 조직학적 변화와 함께 폐암과 관련 있는 EGFR (epidermal growth factor receptor)의 수용기 중 하나인 HER2/neu 종양 유전자와 세포 성장 억제 작용과 악성화 과정에서의 저항성으로 작용하는 TGF-${\beta}_1$을 각각 정량 하도록 하여 인공적인 동소 폐암의 경우 암유전자의 발현에 관하여 조사해보고자 하였다. 대상 및 방법: 면역성이 없는 20마리의 수컷생쥐 (Male BALB/c nude mice)로 5마리를 대조군으로 하였으며, 나머지 15마리는 실험군으로 하고 체중은 20~25 gm (Orient, Japan)의 범위에 있었다. HER2/neu는 채혈하여 보관된 혈액의 혈청을 분리하여 CLIA (chemiluminiscent immunoassay) 법으로 정량적으로 측정하였으며 TGF-${\beta}_1$은 immunosandwitch법을 이용하여 정량 분석하였다. 통계학적 분석을 위하여 SPSS통계(SPSS Version10.0, USA)프로그램을 이용하였으며 Student T test를 하였으며 p값이 0.05 미만인 경우를 유의성이 있는 것으로 간주하였다. 결과: 정상 대조군에서나 인위적으로 주입한 폐암 세포주에 의한 폐암이 만들어진 이후에도 HER2/neu 유전자의 증폭은 전혀 반응을 나타내지 못하였다. 하지만 TGF-${\beta}_1$ 대조군의 정량치는 $28,490{\pm}8,549pg/mL$이었고 폐암 세포 주입군은 $42,362{\pm}14,449pg/mL$로 유의하게 1.48배 높게 나왔다(p<0.483). HER2/neu 유전자와 TGF-${\beta}_1$은 유의한 상관관계가 없는 것으로 나타났다. 결론: TGF-${\beta}_1$유전자는 대조군에 비하여 1.48배 정도의 증폭이 발현되었다. TGF-${\beta}_1$의 증폭은 Nude mice에서 발암에 의한 생체 치유 억제 기전이 확실히 작동하고 있다는 것을 의미하며, 인체의 조기 폐암의 발견에 역할을 가능케 하는 정량 검사법으로 이용할 수도 있을 것이다.