Combined velocity and temperature imaging of gas flow in an engine cylinder.

A combined velocity and temperature measurement method using a high-speed camera, a pulsed UV laser, and temperature-sensitive phosphor particles is proposed. The temperature was calculated from the phosphorescence lifetime, while the velocity was obtained from images of the phosphor particles during a single decay. This method was applied to in-cylinder measurements of gas flow at high temperatures under motoring conditions. Tumble flow was observed at the top dead center. The temperature-change dependence on the crank angle agrees qualitatively with the gas temperature and the pressure.

High speed engine gas thermometry by Fourier-domain mode-locked laser absorption spectroscopy.

We present a novel method for low noise, high-speed, real-time spectroscopy to monitor molecular absorption spectra. The system is based on a rapidly swept, narrowband CW Fourier-domain mode-locked (FDML) laser source for spectral encoding in time and an optically time-multiplexed split-pulse data acquisition system for improved noise performance and sensitivity. An acquisition speed of ~100 kHz, a spectral resolution better than 0.1 nm over a wavelength range of ~1335-1373 nm and a relative noise level of ~5 mOD (~1% minimum detectable base-e absorbance) are achieved. The system is applied for crank-angle-resolved gas thermometry by H(2)O absorption spectroscopy in an engine motoring at 600 and 900 rpm with a precision of ~1%. Influences of various noise sources such as laser phase and intensity noise, trigger and synchronization jitter in the electronic detection system, and the accuracy of available H(2)O absorption databases are discussed.

Development of a system which automatically acquires optimal discrete-valued attributes by dividing and grouping continuous-valued attributes to assist clinical decision making in radiotherapy.

The purposes of this study were first to develop a system which statistically tests results of radiotherapy and which automatically acquires an optimal discrete-valued attribute by dividing and grouping continuous-valued attributes, and second to find the optimal range of values such as tumor dose by taking account of the conditions and statistics in ROGAD (Radiation Oncology Greater Area Database), a multi-institutional database in Japan. Our ultimate goal is to assist clinical decision making for every patient. In this research, two algorithms for acquiring a boundary value were developed without detecting false boundaries or accidental errors of acquired boundaries. The resolution of detected discrete-valued attributes and speed of convergence were confirmed to be practical. The optimal range of given tumor dose with the best reaction and with the fewest complications is expected to be clarified.