Aerospace System
Micro/nano material mechanics laboratory
Staffs
- Mikio MURAOKA (Professor, Dr. Eng.)
- Xu ZHAO (Associate Professor, Dr. Eng.)
- Hiromi ISHIKAWA (Technical Staff)
- Yukiko ISHIGAMI (Staff)
Research interests
Applications of metallic nanocoils (NCs), especially in electromagnetic wave absorption, flexible transparent electrode, transparent film heater, sensors, and actuators. Suppression or applications of atomic diffusion induced by high current density or stress, especially in microelectronics, fabrication of micro/nano materials.
Figure 1 shows a fabricated Pt NC web (Ref.: Muraoka et al., Method for producing metal nanocoil, Patent PCT/JP2016/053789).
Figure 2 shows a flexible transparent film heater (10 mm × 7 mm) made by transferring the Pt NC web onto a 50 μm-thick silicone rubber membrane (left image). The background of the region of Pt NC web can be clearly seen. The infrared thermography image (right image) shows the temperature distribution of the film heater at an applied constant voltage of 16.5 V. An average temperature being about 84.5 ℃ is achieved.
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Heat and fluid flow engineering
Staffs
- Takahiro ADACHI (Professor, Dr. Eng.)
- Kana AKINAGA (Technical Staff)
Research interests
We investigate fluid flow like water and air, and heat transfer theoretically, numerically and experimentally.For example, figure 1 shows a new thermodynamic model of Energy recovery system from the exhaust air discharged from an electric aircraft.Figure 2 shows a simulation result of filmwise lift-up phenomena by using OpenFOAM.Figure 3 shows a autonomous robot using a basic principle of fluid dynamics.
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Raman spectroscopy in mechanical engineering
Staff
- Makoto YAMAGUCHI (Associate Professor, Dr. Sci.)
Research interests
Structural characterization of the sub-surface layer is becoming important in nanotechnology. Raman spectroscopy which is a light scattering phenomenon resulting from the interaction of light and material are useful technique to evaluate the crystal structure, residual stress, and so on.
Figure 1 shows surface enhanced Raman scattering (SERS) spectra on Ag coated ta-C. The signal intensity was up to several times higher than that of surface without coated. of spectrum. We applied SERS technique to characterization for structural of surface layer.
Raman spectroscopy system using quadruple ellipsoidal mirrors is shows in fig.2. The ellipsoid mirror was cut in half along a plane through the major axis and cut again along a plane through a focus perpendicular to the major axis. The incident angle to surface can be set at an arbitrary value by rotating a mirror.
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Fluid mechanics laboratory
Staffs
- Takeshi AKINAGA (Associate Professor, Dr. Eng.)
Research interests
Universality for transition of flow to turbulence
Turbulence is fully random chaotic system which we analyse guided by Kolmogorov's ideas which gives rise to the isotropic homogeneous turbulence. But what if you look at the nature or engineering applications?
Because turbulence usually requires transport and the transport is only possible if the system which is correlation. Note that the isotropic turbulence does not have any finite correlations.
So we could say that the realistic turbulence systems would be driven by transports, and that the simplest one we can imagine is to be homogeneous in two spatial dimensions and in time. Their finite correlations and their also spontaneous structures are driven by the transports. One of our interests is to understand particular structures amongst the many systems which are homogeneous in two spatial dimensions.
Nomenclature: The primary solution as basic state which has all the symmetries of external conditions. Secondary solutions / flows are introduced by the first instability of the primary solution and they generically assume the form of rolls or stripes and they are just two dimensional.
Figure: An example of sequence of bifurcations approach to turbulence in incompressible shear flow: Higher order fully non-linear solutions in the hierarchical bifurcation sequence for the Taylor-Couette flow (TCF) between co-rotating concentric cylinders, as a function of the Reynolds number (Re) for fixed relative angular velocity of the co-rotating cylinders. It shows solutions that interact to produce higher order states en route to turbulence. The corresponding unstable states are not shown for this case.
# The sequence of bifurcation approach to turbulence derives from the proverb “the straw that broke the camel’s back”.
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Aeronautical and astronautical engineering
Staffs
- Hiroshi HIRAYAMA (Lecturer, Dr. Eng.)
Research interests
Dynamics and system engineering about spacecraft and aircraft are interesting subject. Orbital debris is a growing problem in recent space development.Figure 1 shows a conceptual device to inspect surface of spacecraft. That will enable to observe microscopic pits damaged by micro debris, and provide knowledge about existing density of micro debris which cannot be observed from ground. Dynamics of spacecraft when capturing and disposing an orbital debris is also studied.
Exploration on moon and planets is exciting research theme.Figure 2 shows a conceptual lunar exploration probe descending into a vertical hole.
Another topic is electrification of airplane systems. We are studying about power smoothing and system redundancy for electrified flight control system of airplanes.
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Surface nano-imaging laboratory
Staffs
- Yukinori KINOSHITA (Lecturer, Dr. Eng.)
Research interests
Atomic force microscopy (AFM) depicts solid surface structures in nanometer-scale by detecting the local interaction forces between an oscillating sharp tip and a sample surface (Fig.1). AFM works in various environment (in vacuum, air, liquid) and the spatial resolution reaches sub-atomic level on a clean surface in well controlled equipment conditions. Furthermore, surface topographic, mechanical and magnetic properties can be imaged simultaneously (Fig.2). In this lab, we develop novel AFM imaging technique for evaluating the recent advanced electric/magnetic materials or devices such as fine nano-particles or electric/magnetic recording radium.
Fig.1 explanation
The tip is oscillated at near the resonance frequency and scanned over the sample surface. From the shift of the tip resonance oscillation induced by the tip-sample interaction force, surface topographic images are depicted.
Fig.2 explanation
The topographic image indicates the granular structure with sub-nanometer height and the magnetic image indicates the striped magnetic recording pattern (up and down magnetic moments).
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