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We report how the thermopower of complex transition-metal oxides is susceptible to small changes in material parameters. In the A-site ordered perovskite oxide R(2/3)Cu(3)Ti(3.6)Ru(0.4)O(12), the thermopower changes from 15 to -100 microV K(-1) at 300 K in going from R = La to Er. We associate this with the hybridization between Cu 3d and Ru 4d electrons, which depends on R. For stronger hybridization, the Cu 3d electrons become more itinerant leading to positive thermopower. In the A-site ordered perovskite cobalt oxide Sr(3)YCo(4)O(10.5), the spin state of the Co(3+) ions determines the magnitude of the thermopower, where partial isovalent substitution (Ca for Sr and Rh for Co) enhances the thermopower whilst keeping the resistivity intact. These substitutions stabilize the low spin state of the Co(3+) ions, which affects the thermopower through the entropy of the background for the carriers. We propose that the control of the magnetism plays a pivotal role in determining the thermopower in a certain class of complex oxides.

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In minimal quantity lubrication (MQL) machining of aluminum alloys, since they have highly adhesive characteristics, more effective lubrication is necessary. This study therefore proposes that oxygen-including compounds, such as esters, alcohols and acids, are considered to be a potential MQL lubricant. The experimental investigations have shown the cutting performance of those oxygen-including compounds has greatly been influenced by their chemical structures. Some of them have been able to provide the successful cutting performance as a MQL cutting fluid and, in particular, specific alcohols have demonstrated the superior anti-adhesive characteristics in MQL end milling.