Microstructure and Dielectric Properties of Barium-vanadate Glasses

AbstractThe ac and dc conductivity in barium-vanadate glasses was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. The XRD results show that all samples are amorphous but microscopy investigation reveals that glasses with greater amount of V2O5 contain nanostructures. The influence of V2O5 quantity on dielectric properties was checked. The activation energy of dc conduction process was evaluated. On the basis of Jonscher universal dielectric response the temperature dependence of conductivity parameters were determined and compared to theoretical models collected by Elliott

Tetraalkylphosphonium Polyoxometalates as Novel Ionic Liquids.

The pairing of a Lindqvist or Keggin polyoxometalate (POM) anion with an appropriate tetraalkylphosphonium cation, [R{sub 3}R{prime}P]{sup +}, has been shown to yield an original family of ionic liquids (POM-ILs), among them salts liquid at or near ambient temperature. The physicochemical properties of several such 'inorganic liquids', in particular their thermal properties, suggests the possible application of these compounds as robust, thermally-stable solvents for liquid-liquid extraction. A preliminary evaluation of the potential of POM-ILs in this application is presented

The selection of subassemblies for a ground source heat pump

W pracy zostały zaprezentowane wybrane zagadnienia dotyczące projektowania gruntowej pompy ciepła na podstawie publikowanych wyników badań. W celu weryfikacji przyjętej metodyki doboru poszczególnych podzespołów pompy ciepła zostały przeprowadzone badania eksperymentalne na stanowisku badawczym wyposażonym w gruntową pompę ciepła z kolektorami pionowymi.The paper presents selected issues related to the design of a ground source heat pump based on published research results. In order to verify the adopted methodology of selection of the heat pump individual subassemblies experimental investigations were carried out on a test stand equipped with a ground source heat pump fitted with vertical collectors