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A thermoelectric module TM based on natural pyrite has been designed and built up. It is formed by 12 couples of n- and p-type blocks of pyrite from Spain and Germany mines, respectively. Previously, a detailed study of transport properties of different provenances pyrites has been carried out, in order to select adequate specimens. N-type pyrite from Spain with Seebeck coefficient (S)of ~ -600 µV/K and electrical resistivity (r) of ~ 0.24W·cm is used. As p-type pyrite, natural pieces from Germany with S ~ 370µV/K and r ~ 8 W·cm, was chosen. The internal resistance of this device was around 700W, the electric power produced was of about microwatts and the TM efficiency was 2·10-3 %. [ABSTRACT FROM AUTHOR]

This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying parameters such as scanning speed (SS), pulse intensity (PI) and pulse frequency (PF). Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional. [ABSTRACT FROM AUTHOR]