| Research Abstract |
Abstracts of this research results are outlined as follows considering research schedule :
(1) Evaluation method of high pressure volume of lubricant was established by modeling the pressure chamber shape, by the assumption of high pressure refractive index and by calibration experiment for methanol. (2) Measurement of quasi-static high pressure volume resulted that lubricants of bulky-ring molecular structure such as traction oils (SN100, CVT oil) compressed less than those of chain structure such as methanol and a diester DOS. (3) At a few minutes fast compression, the volume change was revealed to be 5 % at 2 GPa and 10 % at 5 GPa smaller than those of quasi-static compression for SN100. The results are the evidences of the prediction that solidified lubricants is hard to compress due to the appearance of shear stress in non equilibrium compression. (4) After fast compression, temperature was elevated up to 160℃ and maintained for a few hours and cooled slowly to room temperature, an
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d then the volume turned out to approach quasi-static one. This result proved the prediction that non equilibrium state approach equilibrium one similar to annealing. (5) A few minutes fast compression was done up to 5 GPa for DOS. The volume change was revealed to be almost the same as that of quasi-static compression. The result was out of the prediction and showed the possibility of non equilibrium state for solidified DOS even at quasi-static compression. (6) Hysteresis by pressure and temperature was different for molecular structure and solidified pressure of each lubricant. (7) Compression velocity-dependent viscoelastic equation of state including volume viscosity was established. Practical calculation is complicated. However, the employment of mathematical auto-processing software facilitate the calculation. (8) Another results not listed in the research schedule were high pressure viscosity measurements up to 2 GPa at 200℃ and the analysis of oil-solidified high pressure traction curve. Less
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