Effects of oxide additive on thermoelectricity of FeSi2
Thermoelectricity has been hot issue in these days, because of environmental problems and energy sources deficit. Moreover, material development for thermoelectricity is now busy in oxide and metal or alloy, basically. However, conclusive materials with good performance have not yet been found in application basis. We have studied oxide-added beta-FeSi2 for these years. Iron disilicide is well known and utilized in relatively higher temperature. In this report, we indicated our successful improvement of performance of beta-FeSi2 added with Ta2O5 showing the figure of merit almost 0.3 times 10-3/K This was obtained by reducing thermal conductivity and electrical resistivity (a half of standard FeSi2)
Large thermoelectric power in NaCo 2 O 4 single crystals
We measured and analyzed the transport properties of single-crystal ${\mathrm{NaCo}}_{2}{\mathrm{O}}_{4}$, which is a metallic transition-metal oxide consisting of a two-dimensional triangle lattice of Co. Reflecting the crystal structure, the resistivity is highly anisotropic between in- and out-of-plane directions, and the in-plane resistivity is as low as 200 $\ensuremath{\mu}\ensuremath{\Omega}$ cm at 300 K. Most strikingly, the in-plane thermoelectric power of ${\mathrm{NaCo}}_{2}{\mathrm{O}}_{4}$ is about 100 $\ensuremath{\mu}$V/K at 300 K, which is nearly ten times larger than that of typical metals. The large thermoelectric power and the low resistivity suggest that ${\mathrm{NaCo}}_{2}{\mathrm{O}}_{4}$ is a potential thermoelectric material.
Review of Literature on Probability of Detection for Magnetic Particle Nondestructive Testing
Abstract : A critical review of the available literature concerning the minimum reliably detectable defect size aNDI for magnetic particle testing (MPT) in aerospace applications is presented. Four probability of detection (POD) studies relevant to detection of fatigue cracks in aircraft components were found over the period 1968 to 2011. As the statistical methods used in these four previous studies were either outdated or otherwise deficient, the original data were reanalysed using currently accepted techniques. A meta-analysis of the results is presented, with emphasis on statistical inferences for the defect size expected to be detected with 90% POD. It is shown that the minimum reliably detectable defect size aNDI = 2.0 mm currently specified by the Royal Australian Air Force for wet fluorescent magnetic particle inspection using the continuous method is consistent with estimates of the average performance of MPT derived from the reanalysis of the literature.