Search

Your search keyword '"Ozawa T"' showing total 106 results
Start Over Author "Ozawa T" Publication Type Conference Materials
106 results on '"Ozawa T"'

1. Effect of speed ratio increase on pressure measurement for hypersonic rarefied gas flows.

Author

Ozawa, T., Suzuki, T., and Fujita, K.

Subjects
GAS flow, PRESSURE measurement, WIND tunnels, SURFACE pressure, HYPERSONIC aerodynamics, SURFACE temperature, COUETTE flow
Abstract

Rarefied aerodynamics need to be accurately estimated for planetary atmospheric entry and earth reentry missions. At Japan Aerospace Exploration Agency (JAXA), the hypersonic rarefied wind tunnel (HRWT) has been developed for rarefied aerodynamic prediction. In order to improve the prediction accuracy of rarefied aerodynamic characteristics, the determination of surface accommodation coefficients and its dependence on speed ratio is crucial. In this work, we have developed a cooling system for models using liquid nitrogen in order to improve speed ratio in HRWT. We have tested cooling pressure tube models in HRWT, and investigated the dependence of tube pressure on surface accommodation coefficients and surface temperature by carrying out direct simulation Monte Carlo (DSMC) computations. Finally, by comparing the measured pressure with the computed results, we discuss the effect of speed ratio increase in HRWT measurements. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

2. Impact of Aspergillus Infection on Prognosis in Severe COVID-19 Patients

Author

Kamimoto, S., primary, Okamori, S., additional, Uchida, T., additional, Ozawa, T., additional, Miyazaki, M., additional, Baba, R., additional, Arai, D., additional, Shinoda, H., additional, Takahashi, H., additional, Hagiwara, Y., additional, Ogura, T., additional, Hagiwara, S., additional, and Nakachi, I., additional

Published
2023
Full Text
View/download PDF

4. Semi-Dirac transport and localization in polaritonic graphene

Author

Real, B., primary, Jamadi, O., additional, Milicevic, M., additional, Pernet, N., additional, St-Jean, P., additional, Ozawa, T., additional, Montambaux, G., additional, Sagnes, I., additional, Lamaitre, A., additional, Le Gratiet, L., additional, Harouri, A., additional, Ravets, S., additional, Bloch, J., additional, and Amo, A., additional

Published
2021
Full Text
View/download PDF

10. Investigation of Condensation and Evaporation Effect on CO2 Hypersonic Rarefied Aerodynamic Measurements.

Author

Ozawa, T., Suzuki, T., and Fujita, K.

Subjects
HYPERSONIC aerodynamics, AERODYNAMIC measurements, CONDENSATION, EVAPORATION (Chemistry), RAREFIED gas dynamics
Abstract

In order to improve the accuracy of CO2 rarefied aerodynamic prediction, we have extended the capability of a hypersonic rarefied wind tunnel (HRWT) to CO2 hypersonic flows at the Japan Aerospace Exploration Agency. Since the determination of accommodation coefficients and direct measurement of rarefied aerodynamic forces are important for the improvement of rarefied aerodynamic predictions, we have utilized both experimental and numerical approaches for investigating the effect of CO2 condensation on HRWT aerodynamic measurements. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

13. Pitot Pressure Analyses in CO2 Condensing Rarefied Hypersonic Flows.

Author

Ozawa, T., Suzuki, T., and Fujita, K.

Subjects
CARBON dioxide, RAREFIED gas dynamics flow, CONDENSATION, HYPERSONIC flow, PITOT tubes
Abstract

In order to improve the accuracy of rarefied aerodynamic prediction, a hypersonic rarefied wind tunnel (HRWT) was developed at Japan Aerospace Exploration Agency. While this wind tunnel has been limited to inert gases, such as nitrogen or argon, we recently extended the capability of HRWT to CO2 hypersonic flows for several Mars missions. Compared to our previous N2 cases, the condensation effect may not be negligible for CO2 rarefied aerodynamic measurements. Thus, in this work, we have utilized both experimental and numerical approaches to investigate the condensation and rarefaction effects in CO2 hypersonic nozzle flows. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

16. Effect of autoionizing states with a high-lying spectator electron on population inversion of nitrogen plasma in recombining phase.

Author

Ozawa, T., Kumai, H., Hotta, E., Horioka, K., and Kawamura, T.

Subjects
PLASMA gases, ULTRAVIOLET radiation, HYDROGEN, IONS, ATOMIC transitions
Abstract

Discharge produced plasma (DPP) is a promising tool to generate effective extreme ultraviolet (EUV) light. A hydrogen-like nitrogen ion emits light at 13.4 nm with an optical allowed atomic transition from n = 3 to 2, where n stands for a principal quantum number. We focus on the properties of population inversion between n =3 and 2 in recombining phase. Population inversion is calculated in the framework of population kinetics, and a gain coefficient G is estimated. In this study, dielectronic-capture ladderlike (DL) processes are included. At high density and low temperature, the DL deexcitations make a large contribution to the population inversion. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

20. Current Development Status and Future Challenges of FeRAM

Author

Fujimori, Y., primary, Kimura, H., additional, Ichida, Y., additional, Iida, J., additional, Ashikaga, K., additional, Ito, H., additional, Ozawa, T., additional, Kanaya, T., additional, Kinouchi, N., additional, Suzuki, T., additional, Date, T., additional, Notsu, D., additional, Fuchikami, T., additional, Zhiyong, Z., additional, Kojima, M., additional, Moriwake, M., additional, and Takasu, H., additional

Published
2010
Full Text
View/download PDF

29. Rarefied aerothermodynamics for Mars aero-flyby sample collection mission.

Author

Ozawa, T., Suzuki, T., Takayanagi, H., and Fujita, K.

Subjects
AEROTHERMODYNAMICS, CONTINUUM mechanics, SIMULATION methods & models, MONTE Carlo method, FREE molecular flow
Abstract

At Japan Aerospace Exploration Agency, a Mars Aero-flyby Sample Collection mission has been proposed. In order to improve the feasibility of the Mars mission, aerodynamic characteristics have been investigated for flow regime from free-molecular to continuum. By carrying out a series of computations, such as free-molecular flow simulations, continuum flow simulations, and direct simulation Monte Carlo (DSMC) rarefied flow simulations, a bridging function method with DSMC parameters was found to represent the aerodynamic characteristics well. In transitional flow regime where Knudsen number is between 0.001 and 10, aerodynamic coefficients are dramatically changed. To keep the stability of the aeroshell in rarefied hypersonic flows, the range of its center of gravity location is restricted within 70% of the body length from the forefront, and real gas effects as well as Martian dust effect on aerodynamics are found to be negligibly small for the mission. [ABSTRACT FROM AUTHOR]

Published
2012
Full Text
View/download PDF

30. DSMC Dusty Flow Simulation for Non-stop Mars Sample Return Mission.

Author

Ozawa, T., Suzuki, T., Takayanagi, H., and Fujita, K.

Subjects
SPACE vehicle aerodynamics, HYPERSONIC aerodynamics, SIMULATION methods & models, MONTE Carlo method, DRAG (Aerodynamics), HEAT flux, MARTIAN dust storms, MARS (Planet)
Abstract

At Japan Aerospace Exploration Agency, a non-stop Mars sample return project has been planned. In the project, sampling of Martian dust particles is planned between 35 and 45 km, and the impact of Martian dust particles on a shock structure and aerodynamics for a spacecraft must be clarified. In this work, a mechanism for hypersonic dusty flow simulations in DSMC has been developed, and hypersonic dusty flows were simulated for clear weather and dust storm conditions using two dust-surface interaction models at the descent altitude. It was found that although the impact of dust particles on the shock structure and drag is negligible, the total heat flux is increased with the consideration of dust particles. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

46. A 4-way VLIW embedded multimedia processor.

Author

Suga, A., Sukemura, T., Takahashi, H., Wada, K., Miyake, H., Nakamura, Y., Takebe, Y., Azegami, I., Hirose, Y., Kimura, M., Okano, T., Shiota, T., Saito, M., Wakayama, S., Ozawa, T., Satoh, T., Sakurai, A., Katayama, T., Abe, K., and Kuwano, K.

Published
2000
Full Text
View/download PDF

50. A 25ns 64K SRAM

Author

Ozawa, T., primary, Koshimaru, S., additional, Kudo, O., additional, Itoh, H., additional, Harashima, N., additional, Yasuoka, N., additional, Asai, H., additional, Yamanaka, T., additional, and Kikuchi, S., additional

Published
1984
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results