Correlation of the scaling exponent of the diffusivity-density function in viscous liquids with their elastic properties

Fundamental thermodynamical concepts and a solid-state point defect elastic model are used to formulate a diffusivity-density scaling function for viscous liquids. It is proved in a straightforward manner that the scaling exponent describing the density scaling of the diffusivity, is related with the pressure derivative of the isothermal bulk modulus.Comment: J. Chem. Phys. (in print

Self-diffusivity as a function of density and temperature in crystalline solids and compensating rules for self-diffusion parameters in Carbon - Subgroup crystals

The self-diffusion coefficient of crystalline solids as a function of density and temperature may derive from thermodynamics concepts and an earlier elastic thermodynamic point defect model [P. Varotsos and K. Alexopoulos, Phys. Rev. B 15, 4111 (1977); Phys. Rev. B 18, 2683 (1978)]. Compensation laws ruling self-diffusion parameters in carbon-subgroup crystals obtained from theoretical calculations are predicted, as well.Comment: Appl. Phys. Letters (accepted for publication

Transformation of polarons to bipolarons in disordered matter

The polaron to bipolaron transition in disordered media under the influence of a broadband ac electric field is suggested: ac conductivity vs. frequency measurements in disordered media with inhomogeneous disorder induce spatio-temporal fluctuations of the density of polarons yielding polaron to bipolaron transformation. The external field results in the transition, alternatively to an increasing doping level. The assertion is confirmed by performing successive complex impedance measurements in disordered media. A systematic increase of the real part of the ac conductivity in the frequency domain, followed by mutual reduction of the magnetic inductivity of conducting polypyrrole, are explained.Comment: 8 pages plus 3 figures. Accepted for publication in Applied Physics Letter

Pressure dependence of the dielectric loss in semi-conducting polypyrrole aged at room temperature

The effect of physical aging of semi-conducting polypyrrole at ambient temperature for two years duration on the dielectric loss at various pressures is investigated. Changes of the dielectric loss spectra and the modification of the values of the activation volume for relaxation are interpreted through the division of chain clusters into smaller components and the reduction of the size of the conductive grains.Comment: Synthetic Metals (in print

Dielectric properties of Granodiorite partially saturated with water and its correlation to the detection of seismic electric signals

Transient electric signals emitted prior to earthquake occurrence are recorded at certain sites in the Earth's crust termed sensitive. These field observations enforce the laboratory investigation of the dielectric response of rocks forming these localities. The dielectric relaxation of granodiorite rock coming from such a sensitive locality (Keratea, Greece) reveals, through complex impedance spectroscopy, that the activation volume for relaxation of this rock is negative which so far has been reported only rarely. This result, however, supports a theoretical model on the pre-seismic electric signals and is likely to be correlated with the sensitivity of the site and hence with the selectivity

‘Reading’ and ‘Translating’ Emotions: Nationalism in Contemporary Greek Cinema

This study explores emotions related to nationalism, and their manifestations in contemporary Greek cinema. It also investigates the reasons and mechanisms giving rise to nationalism, and how it is perceived, expressed and ‘translated’ into other cultures. A core focus within the nationalist paradigm is the theme of national identity, with social exclusion ideologies such as racism operating in the background. Two contemporary Greek films have been chosen, which deal with themes of identity, nationalism, xenophobia, anger and fear in different contexts. The study is carried out by drawing on the theories of emotion, language, translation and cinema, to analyse the visual and audio components of the two films and ascertain their translatability to an Australian audience. Both films depict a similar milieu to each other, which is plagued by the lingering nature of all the unresolved political and national issues faced by the Greek nation, in addition to the economic crisis, a severe refugee crisis, and externally imposed policy issues, as well as numerous other social problems stemming from bureaucracy, red tape and widespread state-led corruption, which have resulted in massive rates of unemployment and financial hardship that have befallen a major part of the population. In spite of their topicality, the themes are universal and prevalent in a number of countries to varying degrees, as cultural borders become increasingly integrated, both socially and economically. It is concluded that nationalism and its underlying emotions are readily translatable between the target cultures of Greece and Australia, as they remain at the core of our political discourse and sociocultural context

Negative activation volume for dielectric relaxation in hydrated rocks

Negative defect activation volumes are extremely rare in solids. Here, we report for the first time that this holds in a couple of hydrated rocks for dielectric relaxation by exploring the complex impedance spectra at various pressures and temperatures. The present findings mean that the relaxation time of the relevant relaxation mechanisms decreases upon increasing pressure, thus it may become too short at higher pressure and hence lead to the emission of transient electric signals before fracture. This may constitute the long-standing laboratory confirmation for the explanation of the generation of electric signals prior to an earthquake, as recently pointed out by Uyeda et al [Tectonophysics 470 (2009) 205-213]