Application of thermoelectric aging models to polymeric insulation in cable geometry

The life expressions of models of insulation ageing are functions of temperature and field as well as material parameters. A methodology is presented that allows these models to be applied to a cable geometry in which there is a radial variation of both field and temperature. In this way material parameters can be extracted from cable data. The methodology is illustrated using one such model and the parameters deduced from cable failure distributions are compared with those obtained for thin films. This comparison allows conclusions to be drawn about how the ageing process affects specimens of the same material with different volumes

Copyright Contracts and Earnings of Visual Creators: A Survey of 5,800 British Designers, Fine Artists, Illustrators and Photographers

There is a common perception that digitisation has prompted changes in creative labour markets. In particular, it is widely assumed that exploiters insist on "grabbing rights" (i.e. broadly conceived assignments of rights), that visual artists are not able to negotiate, that they are paid less and less, and that they are compelled to waive their moral rights. This study suggests a much more equivocal picture. In place of a straightforward narrative of decline, the results of the survey suggest that in most fields there has been less change over the last decade than one might have expected: that, terms of exploitation are most often about the same. That is not to say that there are no discernible changes in particular occupations and media. Respondents and interviewees identify some important shifts. Perhaps surprisingly, it seems there are changes in practice that are, from the creator's perspective, both positive and negative. The most positive change is identified amongst the fine artists where half (50%) see their personal bargaining position as having improved, with only 6% perceiving a weakening. The most disturbing changes are in relation to photographers. About half of all photographers (49%) say their bargaining position has worsened, with only 22% reporting improvements. A significant percentage of photographers (40%) report an increase in assignments (compared with 6% who think they have decreased). Moreover, 24% report an increase in moral rights waivers (compared to 3% who identify a decrease), and a decline in the practice of attribution. 31% of photographers see attribution as decreasing over the last decade, and only 8% increasing. 28% say income from secondary use has decreased, while only 16% say it has decreased

Application of polymer ageing models to power cables

Ageing models have been developed to predict the lifetime of polymeric insulation subject to electro-thermal stresses. We present here a method for applying the models to situations in which the field is not constant over the whole specimen, as for cable geometry. The method has been applied to characteristic lifetime data from AC ageing experiments on cables. The results are presented, and the effect of insulation volume upon the model parameters is discussed

Charge-ice dynamics in the negative thermal expansion material Cd(CN)2_2

We use variable-temperature (150--300\,K) single-crystal X-ray diffraction to re-examine the interplay between structure and dynamics in the ambient phase of the isotropic negative thermal expansion (NTE) material Cd(CN)$_2$. We find strong experimental evidence for the existence of low-energy vibrational modes that involve off-centering of Cd$^{2+}$ ions. These modes have the effect of increasing network packing density---suggesting a mechanism for NTE that is different to the generally-accepted picture of correlated Cd(C/N)$_4$ rotation modes. Strong local correlations in the displacement directions of neighbouring cadmium centres are evident in the existence of highly-structured diffuse scattering in the experimental X-ray diffraction patterns. Monte Carlo simulations suggest these patterns might be interpreted in terms of a basic set of `ice-rules' that establish a mapping between the dynamics of Cd(CN)$_2$ and proton ordering in cubic ice VII.Comment: 5 pages, 5 figures, submitted to PR

Effect of Different Types of Physical Activity on Activities of Daily Living in Older Adults : Systematic Review and Meta-Analysis

Peer reviewedPostprin