Two Words, One Meaning: Evidence of Automatic Co-Activation of Translation Equivalents

Research on the processing of translations offers important insights on how bilinguals negotiate the representation of words from two languages in one mind and one brain. Evidence so far has shown that translation equivalents effectively activate each other as well as their shared concept even when translations lack of any formal overlap (i.e., non-cognates) and even when one of them is presented subliminally, namely under masked priming conditions. In the lexical decision studies testing masked translation priming effects with unbalanced bilinguals a remarkably stable pattern emerges: larger effects in the dominant (L1) to the non-dominant (L2) translation direction, than vice versa. Interestingly, this asymmetry vanishes when simultaneous and balanced bilinguals are tested, suggesting that the linguistic profile of the bilinguals could be determining the pattern of cross-language lexico-semantic activation across the L2 learning trajectory. The present study aims to detect whether L2 proficiency is the critical variable rendering the otherwise asymmetric cross-language activation of translations obtained in the lexical decision task into symmetric. Non-cognate masked translation priming effects were examined with three groups of Greek (L1)–English (L2) unbalanced bilinguals, differing exclusively at their level of L2 proficiency. Although increased L2 proficiency led to improved overall L2 performance, masked translation priming effects were virtually identical across the three groups, yielding in all cases significant but asymmetric effects (i.e., larger effects in the L1 → L2 than in the L2 → L1 translation direction). These findings show that proficiency does not modulate masked translation priming effects at intermediate levels, and that a native-like level of L2 proficiency is needed for symmetric effects to emerge. They furthermore, pose important constraints on the operation of the mechanisms underlying the development of cross-language lexico-semantic links

Space Charge Formation and its Modified Electric Field under Applied Voltage Reversal and Temperature Gradient in XLPE Cable

The results of space charge evolution in cross-linked polyethylene power cables under dc electrical field at a uniform temperature and during external voltage polarity reversal are presented in the paper. A mirror image charge distribution was observed in the steady state, but the pre-existing field altered the way in which the steady state charge distribution was formed from that obtaining when the cable was first polarized. Polarity reversing charge was generated in the middle of the insulation and moved towards the appropriate electrodes under the influence of a field in excess of the maximum applied field. Our results show that the mirror effect is a steady state effect that is due to crossinterface currents that depend only on the interface field and not its polarity. Measurements on cable sections with an elevated mean temperature and temperature gradient show that the interface currents are temperature dependent, and that differences between the activation energies of the interface and bulk currents can eliminate and possibly even invert the polarity of the space charge distributio

Aging mechanisms of polymeric materials under DC electrical stress: A new approach and similarities to mechanical aging

The main fundamental mechanisms proposed for the aging of polymeric insulation to breakdown at the DC design field are reviewed. A correlation between the action of static mechanical stress affecting the whole insulation volume, and DC electric-mechanical stress providing local strain large enough to bring the polymer to plastic deformation is hypothesized. With the corollary that local plastic deformation leads to the formation of cavities, or crazes, of size large enough to trigger highly energetic phenomena and bring about insulation failure, an inter-relationship between mechanical and electrical life models can be obtained and supported by calculation and fitting to experimental results. The influence of space charge is discussed and it is argued that it would play a central role in DC ageing even if its presence is not a precondition

The role of group polarization in the formation of fast charge pulses in polyethylene

Recent calculations on the small charge pulses observed to move in millimetre thick polymeric insulation at high speeds have suggested that the charges may take the unusual form of electron pairs bound together by local lattice deformation. Here we show how the global lattice deformation generated around such a pulse can produce a potential well in which local electron paired states are the most stable form for the carriers and in which they are bound together such that in an electric field they must transport together as a single unit

Effect of mechanical stress on fast pulse-like conduction in XLPE based materials

The aim of this paper is to investigate the relationship between mechanical stress and a new conduction mechanism discovered recently, that is conduction through fast charge pulses in insulting polymers. Theories and experimental data suggested that such pulses constitute charge solitons moving in the insulation bulk thanks to the induced compressive force applied to the natural relaxation of the polymer chains. This paper supports such picture. Experimental tests carried out under mechanical stress, in fact, show that charge pulse transport is significantly affected by insulation compression. In particular, charge pulse amplitude decreases and positive pulses disappear as mechanical stress is increased. On the contrary, negative pulse mobility increases with the applied stress

Fast pulse-like conduction in XLPE based materials detected through charging current measurements

Recent papers have shown small, but repetitive, charge pulses of both polarities, travelling very fast in polyethylene and nanostructured epoxy resin specimens at moderate electric fields. This paper shows that such charge pulses can be detected also by means of charging current measurements, once the measuring system is properly modified in order to acquire small signals with high dynamics, through attenuation of the low-frequency content of the polarization current. These measurements are shown to be sometimes even more sensitive in detecting charge pulses than space charge measurements, thus they can be used successfully to evaluate pulse repetition frequency and amplitude at such fields where these conduction mechanisms are incepted