CSVT as a Technique to Obtain Nanostructured Materials: WO3-x
The growth of tungsten oxide nanowires on silicon substrates without using any catalyst is demonstrated by means of close-spaced vapor transport (CSVT) technique at atmospheric pressure. The source was formerly prepared from a tungsten foil to produce a tungsten oxide film. CSVT array is completed with silicon substrates located at a distance of ~350 m over the tungsten oxide source at moderate temperatures (~750°C). Two distinct kinds of nanostructures were produced; a uniform distribution of free standing tungsten oxide wires of several micrometers in length with diameters less than 150 nm; and wires assembled to form nanowire bundle. The X-ray diffraction characterizations show that the phases of WO2.7 and WO2.9 are present.
The aim of this study was to evaluate environmental benefits resulting from the construction of a Sewage Treatment Plant (STP) in Mitilini, Greece. The main benefits identified were the improvement of the coastal water quality and subsequent impacts on citizens’ activities. The valuation was conducted using the Contingent Valuation Method (CVM) through the elicitation of individuals’ willingness to pay (WTP). Due to the significant amount of zero and protest responses, different measurements of mean WTP were calculated and the need for further research on social factors which influence individuals’ valuation is emphasized.