Cavitation Characteristics of Restriction Orifices (Experiment for Shock Pressure Distribution by Cavitation on Restriction Orifices and Occurrence of Cavitation at Multiperforated Orifices Due to Interference of Butterfly Valve)

This paper presents two experimental investigations for cavitation characteristics of restriction orifices. The first experiment is about the spatial distribution of cavitation shock pressure in a pipe at the downstream of restriction orifices. The second experiment is the investigation of butterfly valve throttling to the cavitation in a multiperforated orifice installed piping. From the results of the experiment for the cavitation shock pressure, it is concluded the maximum shock pressure remarkably increases with the decrease of cavitation number regardless of the orifice types. The maximum shock pressure becomes smallest on cone type orifice, and largest on single hole orifice. Multiperforated orifice is between this two. The results of the experiment for occurrence of cavitation due to the interference of butterfly valve show that the cavitation occurs at a relatively high cavitation number when the multiperforated orifice is placed at 1D downstream of the butterfly valve. The butterfly valve throttling accelerates the cavitation at the multiperforated orifice because of the closed orifice installation

How can robots facilitate social interaction of children with autism?: Possible implications for educational environments

Children with autism have difficulties in social interaction with other people and much attention in recent years has been directed to robots as therapy tools. We studied the social interaction between children with autism and robots longitudinally to observe developmental changes in their performance. We observed children at a special school for six months and analyzed their performance with robots. The results showed that two children adapted to the experimental situations and developed interaction with the robots. This suggests that they changed their interaction with the robots from an object-like one into an agentlike one

Zn-induced wipeout effect on Cu NQR spectra in La2−x_{2-x}Srx_xCu1−y_{1-y}Zny_yO4_4

We report a systematic study of Zn-substitution effect on Cu NQR spectrum for high $T_c$ superconductors La$_{2-x}$Sr$_x$Cu$_{1-y}$Zn$_y$O$_4$ from carrier-underdoped to -overdoped regimes (polycrystalline samples, $x$ =0.10, 0.15, and 0.20). We observed no appreciable wipeout effect for the overdoped samples, a gradual and partial wipeout effect below about 80 K for the optimally doped ones, and very abrupt and full wipeout effect below about 40 K for the underdoped ones. The wipeout effect indicates a highly enhanced spectral weight of Cu spin fluctuations at a low frequency. We associate the wipeout effect with a Zn-induced local magnetism far above 40 K and with a localization effect below 40 K.Comment: 2 pages, 3 figures, accepted for publication in Physica C (LT23, Hiroshima 2002