Photothermal measurement of thermal diffusivity in carbonyl iron powder suspensions

We have measured the thermal diffusivity of micron size Carbonyl Iron Powder suspension in a silicone oil base fluid, at various Carbonyl Iron Powder concentrations by means of a photothermal technique called Thermal Wave Cavity. Using literature data (density and specific heat capacity) we can determine the effective thermal conductivity. We compare our experimental results with various theoretical models for the effective thermal conductivity in heterogeneous materials, previously deployed in the literature

Photoluminescence characteristics of soft PZT 53/47 ceramic doped at A and/or B sites

Abstract This study presents the photoluminescence characteristics of the PZT 53/47 system doped at A and/or B sites, with Nb (PZTN), La (PLZT), and Nb–La (PLZTN) in the concentration range from 0.2 to 1.0 molar fraction. The intensity of the emission bands of the system PZTN is two orders higher than the intensity of the emission bands of the systems PLZT and PLZTN, and these emission bands are located at 1.73 eV (718 nm), 2.56 eV (485 nm), and 2.93 eV (424 nm). The origin of the luminescence in these systems is associated with lead and oxygen vacancies produced during the sintering process. The results from X-ray diffraction (XRD) show a mixture of rhombohedral and tetragonal phases. The system PZTN shows a higher tetragonal phase concentration, while PLZT and PLZTN systems show a higher rhombohedral phase concentration. The cell volume shows an increase with dopant concentration only in the case of the PLZTN system. The band gap energy shows a small variation in the PZTN and PLZTN cases around 3.0 eV, a close value to the band gap energy of the pure PZT 53/47 sample. The system PLZT shows an increasing behavior until 4.41 eV for the higher dopant concentration