Wyniki wyszukiwania - BazTech

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Friction-induced oscillations of a non-asbestos organic pin sliding on a steel disc

Nosko O., Nagamine T., Mori H., Sato Y.

Acta Mechanica et Automatica

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2015

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Vol. 9, no. 2

84--88

EN

Friction-induced oscillations result in deterioration of performance of disc brakes and are generally undesired. We conduct experimental study of friction-induced oscillations in a non-asbestos organic material / steel pair used in disc brakes of motor vehicles. The tests are done by use of a pin-on-disc machine in which the pin sample is supported on a deformable beam. The adjustable friction parameters are the disc velocity, contact pressure and temperature. The tests show that the friction coefficient decreases with the sliding velocity and increases with the temperature. The friction-induced tangential oscillation of the pin sample occurs with a frequency equal to the first natural frequency of the beam. The effects of the disc velocity and temperature on the oscillation characteristics are investigated. The oscillation amplitude increases with the disc velocity on the interval of velocities below 2 m/s. Temperature changes of several tens of degrees Celsius lead to the oscillation occurrence / decay. The obtained results can be useful for prognostication of friction-induced oscillations in disc brakes with non-asbestos organic pads.

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Towards Safer Navigation of Hydrofoils: Avoiding Sudden Collisions with Cetaceans

Kato H., Yamada H., Shakata K., Odagawa A., Kagami R., Yonehara Y., Terada M., Sakuma K., Mori H., Tanaka I., Sugioka H., Kyo M.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2012

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Vol. 6, no. 1

143--147

EN

Recently, sudden collisions between large cetaceans and high-speed hydrofoils have become problematic to Japanese sea transport in some localities. We therefore initiated a project to investigate ap-proaches for minimizing risk to both ships and cetaceans. Under the present project, the following three sub-projects are underway: clarifying which whale species are found near sea routes and determining their season-al variations; identifying whale species that have a high collision risk; and determining the unique acoustic characteristics of high-collision-risk cetaceans for the improvement of underwater speakers (UWS). By con-ducting acoustic surveys using novel methods, including an anatomical approach based on characteristics of the inner ear, the aim of this project is to accurately estimate the audible range of species with a high collision risk and improve the sounds generated by the UWS. Thus far, we have identified the cetacean species at high-risk in two major sea routes. In the next phase of the study we plan to develop an imaging system that recog-nizes a cetacean's unique blow using an infrared camera, in an attempt to warn of the approach of high-collision-risk whale species at an early stage by sounding an alarm.

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Nanostructures of binary and ternary Fe-B based glasses studied by HREM and electron diffraction.

Hirotsu Y., Hirata A., Hanada T., Mori H.

Archives of Materials Science

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2005

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Vol. 26, nr 1-2

25-29

EN

In order to clarify local structural characteristic of Fe-B based metallic glasses, HREM and electron diffraction studies were performed for binary Fe-B and ternary Fe-Nb-B glasses. From HREM and nano-diffraction studies, structures with "nanoscale phase separation" were observed in these metallic glasses. The bcc-type and compound-type clusters were actually found in both the glasses by nanobeam diffraction. HREM results showed, however, that the extension of the structure of nanoscale phase separation was smaller in the ternary glass, reflecting its high glass forming ability.

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Experimental and theoretical study on proton tunneling in jet-cooled 9-hydroxyphenalenone-CO2 van der Waals complex

Mori H., Furusawa J., Sekiya H.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 4

451-462

EN

The fluorescence excitation, dispersed fluorescence, and hole-burning spectra of the 9-hydroxyphenalenone (9HPO)-C(2) 1:1 complex have been measured to investigate the effects of the van der Waals interaction on proton tunneling in the So state. The Si-So electronic origin is only 4 cm (-1) red-shifted with respect to that of the monomer, suggesting that proton tunneling occurs in both the So and Si states of the 9HPO-CO(2) complex, although the tunneling splittings have not been observed in the excitation spectrum. The structure of the observed complex and its tunneling potential for the So state of 9HPO have been theoretically investigated by using the reaction surface Hamiltonian method. The intermolecular interaction significantly changes the shape of two dimensional potential energy surface along the reaction coordinates, and slightly decreases the tunneling splitting in the zero-point level.