• Title/Summary/Keyword: shock-shock interaction

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Experience of Becoming a Father of a High Risk Premature Infant (고위험 미숙아 자녀의 아버지 되어감 경험)

  • Park, Jeong Eon;Lee, Byoung Sook
    • Journal of Korean Academy of Nursing
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    • v.47 no.2
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    • pp.277-288
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    • 2017
  • Purpose: This study was performed to identify the experience of becoming a father of a high risk premature infant. Methods: Grounded theory was used for this research. The participants were 12 fathers who had premature infants lighter than 2,500g of birth weight, less than 37 weeks of gestational age and having stayed 2 weeks or longer in a NICU right after birth. Theoretical sampling was done to identify participants and indepth interviews were done for the data collection. For data analysis, the process suggested by Corbin and Strauss was used. Results: For these participants the core phenomenon of the experience of becoming a father of a high risk premature infant was 'striving through with belief and patience'. The phenomenon was 'being frustrated in an unrealistic shock'. Contextual conditions were 'uncertainty in the health status of the premature baby' and 'no one to ask for help' and intervening conditions were 'possibility in the health recovery of the premature baby' and 'assistance from significant others'. Action/interaction strategies were 'withstanding with belief in the baby' and 'enduring with willpower as head of the family' and the consequence was 'becoming a guardian of the family'. Conclusion: For the participants, the process of becoming the father of a high risk premature infant was striving through the situation with belief in their babies' ability to overcome the crisis and waiting for the babies' recovery with patience.

The Potato Transcriptional Co-activator StMBF1 Is Up-regulated in Response to Oxidative Stress and Interacts with the TATA-box Binding Protein

  • Arce, Debora Pamela;Tonon, Claudia;Zanetti, Maria Eugenia;Godoy, Andrea Veronica;Hirose, Susumu;Casalongue, Claudia Anahi
    • BMB Reports
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    • v.39 no.4
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    • pp.355-360
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    • 2006
  • To gain a better understanding on the function of the potato Solanum tuberosum Multiprotein Bridging Factor 1 protein (StMBF1) its interaction with the TATA box binding protein (TBP) was demonstrated. In addition we reported that StMBF1 rescues the yeast mbf1 mutant phenotype, indicating its role as a plant co-activator. These data reinforce the hypothesis that MBF1 function is also conserved among non closely related plant species. In addition, measurement of StMBF1 protein level by Western blot using anti-StMBF1 antibodies indicated that the protein level increased upon $H_2O_2$ and heat shock treatments. However, the potato $\beta$-1,3-glucanase protein level was not changed under the same experimental conditions. These data indicate that StMBF1 participates in the cell stress response against oxidative stress allowing us to suggest that MBF1 genes from different plant groups may share similar functions.

Unsteady Separation Characteristics of Air-Launching Rocket from Full-Geometry Mother Plane (초음속 공중발사를 위한 전기체-로켓의 비정상 분리 유동특성)

  • Ji, Young-Moo;Byun, Yung-Hwan;Park, Jun-Sang;Lee, Jae-Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.6
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    • pp.474-482
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    • 2007
  • An analysis is made for flow and rocket motion during a supersonic separation stage of an air-launching rocket(ALR) from the mother plane. Three-dimensional compressible Navier-Stokes equations are numerically solved to analyze the steady/unsteady flow fields around the rocket which is being separated from the mother plane configuration(F-4E Phantom). Simulation results clearly demonstrate the effect of shock-expansion wave interaction around both of the rocket and the mother plane. To predict the behavior of the ALR by the change of the center-of-gravity, three cases of numerical analysis are performed. As a result, a design-guideline of supersonic air-launching rockets for safe separation is proposed.

Optimization for Component Noise Validation Test by Evaluation of Noise Control Factors for Suspension (현가장치 소음 발생인자 평가를 통한 부품소음 검증시험 최적화)

  • Son, Myungkoon;Lee, Taeyong;Lee, Sangbok;Lee, Seul
    • Transactions of the Korean Society of Automotive Engineers
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    • v.25 no.3
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    • pp.344-349
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    • 2017
  • Suspension noise from under a passenger car is one of the important factors that impact the perceptual quality for drivers. However, it is difficult to validate this by component level testing in the early stage of development, because suspension noise caused by interaction of the related parts has been found at saleable vehicles late during development or at the manufacturing stage, when many customers have already filed for claims. This study proposed a validation testing under research by the DFSS process that enables reproduction of vehicle level noise by component level testing using a shock absorber with the related parts, such as urethane bumper and top mount. This study also developed a compromised test matrix while analyzing the noise factors through experimental design and analysis of variance to determine what factors can affect noise. Based on this study, we expect that the vehicle level and customer claim can be validated during initial development timing by a more reliable component noise validation test.

Supercompact Multiwavelets for Three Dimensional Flow Field Simulation (3차원 유동 시뮬레이션을 위한 Supercompact 다중 웨이블릿)

  • Yang, Seung-Cheol;Lee, Do-Hyung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.12
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    • pp.18-25
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    • 2005
  • This paper presents a supercompact multi-wavelet scheme and its application to fluid simulation data. The supercompact wavelet method is an appropriate wavelet for fluid simulation data in the sense that it can provide compact support and avoid unnecessary interaction with remotely located data (e.g. across a shock discontinuity or vortices). thresholding for data compression is applied based on a covariance vector structure of multi-wavelets. The extension of this scheme to three dimensions is analyzed. The numerical tests demonstrate that it can allow various analytic advantages as well as large data compression ratios in actual practice.

An experimental study on the flow characteristics of a supersonic turbine cascade with the leading edge chamfer angle (초음속 터빈의 익렬 앞전 모서리각에 따른 유동 특성에 대한 실험적 연구)

  • Cho Jong-Jae;Kim Kui-Soon;Jeong Eun-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.361-366
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    • 2006
  • A small supersonic wind tunnel was designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The supersonic cascade with a 2-dimensional supersonic nozzle was tested for the leading edge chamfer angle $(\gamma)$ of the supersonic turbine that is the one of the turbine design parameter. Firstly, the flow was visualized by a single pass Schlieren system. Next, total and static pressure of the cascade were measured by a pressure scanning system. Finally, highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions, flow characteristics of the supersonic turbine were observed.

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Center-of-Gravity Effect on Supersonic Separation from the Mother Plane (무게중심 변화에 따른 초음속 공중발사 로켓의 모선분리 연구)

  • Ji Young-Moo;Lee Jae-Woo;Byun Yung-Hwan;Park Jun-Sang
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.36-40
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    • 2006
  • An analysis is made of flow and rocket motion during a supersonic separation stage of air-launching rocket(ALR) from the mother plane. Three-dimensional compressible Navier-Stokes equations is numerically solved to analyze the steady/unsteady flow field around the rocket which is being separated from the mother plane configuration(F-4E Phantom). The simulation results clearly demonstrate the effect of shock-expansion wave interaction between the rocket and the mother plane. To predict the behavior of the ALR according to the change of the C.G., three cases of numerical analysis are performed. As a result, a design-guideline of supersonic air-launching rocket for the safe separation is proposed.

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NUMERICAL ANALYSIS OF TWO- AND THREE-DIMENSIONAL SUBSONIC TURBULENT CAVITY FLOWS (2차원과 3차원 아음속 공동 유동 특성에 대한 수치적 연구)

  • Choi, Hong-Il;Kim, Jae-Soo
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.187-193
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    • 2007
  • The flight vehicles have cavities such as wheel wells and bomb bays. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves. Resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. In the present study, numerical analysis was performed for cavity flows by the unsteady compressible three dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with Wilcox's ${\kappa}\;-\;{\omega}$ turbulence model. The cavity has the aspect ratios of 2.5, 3.5 and 4.5 for two-dimensional case, same aspect ratios with the W/D ratio of 2 for three-dimensional case. The Mach and Reynolds numbers are 0.53 and 1,600,000 respectively. The flow field is observed to oscillate in the "shear layer mode" with a feedback mechanism. Based on the SPL(Sound Pressure Level) analysis of the pressure variation at the cavity trailing edge, the dominant frequency was analyzed and compared with the results of Rossiter's formula. The MPI(Message Passing Interface) parallelized code was used for calculations by PC-cluster.

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NUMERICAL ANALYSIS FOR TURBULENT FLOW AND AERO-ACOUSTIC OVER A THREE DIMENSIONAL CAVITY WITH LARGE ASPECT RATIO (3차원 고세장비 공동 주위의 난류유동 및 음향 특성에 관한 수치적 연구)

  • Mun, P.U.;Kim, J.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03a
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    • pp.297-301
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    • 2008
  • The flight vehicles have cavities such as wheel wells and bomb bays. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves. Resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. The flow field is observed to oscillate in the "shear layer mode" with low aspect ratio. In the present study, numerical analysis was performed for cavity flows by the unsteady compressible three dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with Wilcox's $\kappa$-$\omega$ turbulence model. The flow field is observed to oscillate in the shear layer mode" with large aspect ratio. Based on the SPL(Sound Pressure Level) analysis of the pressure variation at the cavity trailing edge, the dominant frequency was analyzed and compared with the results of Rossiter's formul. The aero-acoustic wave analyzed with CPD(Correlation of Pressure Distribution).

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NUMERICAL ANALYSIS FOR TURBULENT FLOW AND AERO-ACOUSTIC OVER A THREE DIMENSIONAL CAVITY WITH LARGE ASPECT RATIO (3차원 고세장비 공동 주위의 난류유동 및 음향 특성에 관한 수치적 연구)

  • Mun, P.U.;Kim, J.S.
    • 한국전산유체공학회:학술대회논문집
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    • 2008.10a
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    • pp.297-301
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    • 2008
  • The flight vehicles have cavities such as wheel wells and bomb bays. The flow around a cavity is characterized as unsteady flow because of the formation and dissipation of vortices due to the interaction between the freestream shear layer and cavity internal flow, the generation of shock and expansion waves. Resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. The flow field is observed to oscillate in the "shear layer mode" with low aspect ratio. In the present study, numerical analysis was performed for cavity flows by the unsteady compressible three dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with Wilcox's ${\kappa}-{\varepsilon}$ turbulence model. The flow field is observed to oscillate in the "shear layer mode" with large aspect ratio. Based on the SPL(Sound Pressure Level) analysis of the pressure variation at the cavity trailing edge, the dominant frequency was analyzed and compared with the results of Rossiter's formul. The aero-acoustic wave analyzed with CPD(Correlation of Pressure Distribution).

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