Non-Contact and Self-Calibrated Photopyroelectric Method for Complete Thermal Characterization of Porous Materials.

A general theory of a photopyroelectric (PPE) configuration, based on an opaque sample and transparent pyroelectric sensor, backing and coupling fluids is developed. A combined back-front detection investigation, based on a frequency scan of the phase of the PPE signals, followed by a self-normalization of the phases' behavior, leads to the possibility of simultaneously measuring both thermal effusivity and diffusivity of a solid sample. A particular case of this configuration, with no coupling fluid at the sample/backing interface and air instead of coupling fluid at the sample/sensor interface (non-contact method) is suitable for simultaneous measurement ofboth thermal diffusivity and effusivity (in fact complete thermal characterization) of porous solids.

Improved Photopyroelectric (PPE) Configuration for Thermal Effusivity Investigations of Porous Solids.

A new photopyroelectric detection configuration is proposed in order to measure the thermal effusivity of porous solids. Compared with the previously reported detection scheme this configuration makes use of a transparent window in front of the pyroelectric sensor. In such a way, the heat losses by convection at the sensor's irradiated surface are eliminated, and consequently, the conduction remains the only process responsible for the heat propagation in the whole detection cell.

Comprehensive mineralogical and physicochemical characterization of recent sapropels from Romanian saline lakes for potential use in pelotherapy.

In this study we aimed to compare the mineralogical, thermal, physicochemical, and biological characteristics of recent organic carbon-rich sediments ('sapropels') from three geographically distant Romanian lakes (Tekirghiol and Amara, SE Romania, and Ursu, Central Romania) with distinct hydrogeochemical origins, presently used for pelotherapy. The investigated lakes were classified as inland brackish Na-Cl-sulfated type (Amara), coastal moderately saline and inland hypersaline Na-Cl types (Tekirghiol and Ursu, respectively). The settled organic matter is largely composed of photosynthetic pigments derived from autochthonous phytoplankton.

Photopyroelectric Investigation of Thermal Effusivity of Binary Liquid Mixtures by FPPE-TWRC Method.

An alternative front photopyroelectric configuration (FPPE) that uses the thermal wave resonator cavity method (TWRC) is proposed for measuring the thermal effusivity of a liquid, inserted as backing in the detection cell. A theory for a 5 layers (air, sensor, coupling fluid, solid separator layer, and liquid backing) detection cell is developed. The method seems to be particularly suitable when measuring the thermal effusivity of binary liquid mixtures.