Ternary blends for polymer bulk heterojunction solar cells

The objective of this mini‐review is to outline current major ternary blends used in the active layer of polymer bulk heterojunction photovoltaic solar cells and to give an insight into the direction of the field. The use of a third‐component material in polymer ? fullerene blends is described in two sections. On the one hand, the first family of solid state additives enables us to enlarge photon collection by expanding the action spectra of the solar cells. The second section deals with materials used to engineer bulk heterojunction morphology at the nanoscale. The different approaches explored for many of the ternary blend systems suggest the great potential of such mixtures to significantly improve the optoelectronic properties of solar cells on a long‐term basis. © 2013 Society of Chemical Industry     

Effects of reduced oxygen environment on the reaction to fire of a poly(urethane‐isocyanurate) foam

Thanks to their thermal insulation properties, rigid polyisocyanurate foams are commonly used in the modern built environment, as well as in transportation and industrial applications. However, the fire behaviour of this kind of foam remains one of the most limiting factors for their wider use as insulation material in some sectors. Indeed, this type of material is thermally and chemically reactive. The general scope of this study is to investigate the effects of a reduced oxygen atmosphere on the reaction to fire of flame‐retardant polyisocyanurate foam. This paper reports the results of an experimental campaign, which was performed using a controlled‐atmosphere cone calorimeter, coupled to a Fourier transform infrared spectrophotometer. The dependence of the results on both oxygen concentration and irradiance level is presented and discussed. The chemical compositions of the identified gaseous products were qualified and quantified during both the decomposition and the combustion processes. Copyright © 2016 John Wiley & Sons, Ltd.     

Nonintrusive coupling of 3D and 2D laminated composite models based on finite element 3D recovery

In order to simulate the mechanical behavior of large structures assembled from thin composite panels, we propose a coupling technique, which substitutes local 3D models for the global plate model in the critical zones where plate modeling is inadequate. The transition from 3D to 2D is based on stress and displacement distributions associated with Saint‐Venant problems, which are precalculated automatically for a simple 3D cell. The hybrid plate/3D model is obtained after convergence of a series of iterations between a global plate model of the structure and localized 3D models of the critical zones. This technique is nonintrusive because the global calculations can be carried out using commercial software. Evaluation tests show that convergence is fast and that the resulting hybrid model is very close to a full 3D model. Copyright © 2014 John Wiley & Sons, Ltd.     

Do men and women differ in their use of tables and graphs in academic publications?

In psychological research there is huge literature on differences between the sexes. Typically it used to be thought that women were more verbally and men more spatially oriented. These differences now seem to be waning. In this article we present three studies on sex differences in the use of tables and graphs in academic articles. These studies are based on data mining from approximately 2,000 articles published in over 200 peer-reviewed journals in the sciences and social sciences. In Study 1 we found that, in the sciences, men used 26 % more graphs and figures than women, but that there were no significant differences between them in their use of tables. In Study 2 we found no significant differences between men and women in their use of graphs and figures or tables in social science articles. In Study 3 we found no significant differences between men and women in their use of what we termed ‘data’ and ‘text’ tables in social science articles. It is possible that these findings indicate that academic writing is now becoming a genre that is equally undertaken by men and women.     

Phase Evolution During the Liquid-Phase Bonding of Zirconium and Austenitic Stainless Steel with Zinc Insertion

Liquid-phase bonding experiments were performed at 1073?K (800?°C) between ZIRCALOY-2 and type 316 austenitic stainless steel by inserting zinc as an interlayer. The evolution of the microstructure at the interface was studied and the formation of various phases was detected. On the zirconium side, the very rapid formation of Zn₃Zr was detected, whereas on the steel side, an unexpectedly large amount of the base austenitic steel was observed to react with liquid Zn. The reacted iron solidified into a nickel-poor ferritic phase containing around 10?mol?pct?zinc, which grew into the austenite accompanied by a formation of a zinc-rich phase containing nickel. The reaction stopped when the zinc-rich phase reached saturation with a nickel content between 20 and 25?mol?pct. Thermodynamic calculations showed that the addition of nickel to liquid zinc greatly decreases the free energy of the liquid phase, thus enabling a large stability range for the ferrite?+?liquid zone and reducing the stability range of the austenite. The primary equilibrium between the austenite and the liquid phase is thus metastable, and thus, the austenite transforms into ferrite and a high-nickel-content liquid. The transformation front then progresses until ternary equilibrium is reached between austenite, ferrite, and the zinc-rich phase.     

Remote collaboration in virtual reality: asymmetrical effects of task distribution on spatial processing and mental workload

In the context of a remote collaboration task in virtual reality, this study aimed to analyze the effects of task distribution on the processing of spatial information and mental workload in spatial dialogs. Pairs of distant participants with specific roles (a guide and a manipulator) had to collaboratively move a virtual object in a plane factory mock-up. The displays allowed the participants to be immersed together in the virtual environment. We analyzed the dialogs that took place according to the frames of reference and the mental transformations required to produce the spatial statements. We also measured the associated mental workload. Results showed that when participants took a perspective, the manipulator’s point of view was preferred. Perspective-taking only yielded a moderate increase in mental rotations, which may explain a specifically high mental demand score for the guides’ NASA-TLX. Overall, this is in accordance with the least collaborative effort principle. This study reinforces the idea that, in collaboration, operators do not need the same aids as each other. Thus, it is not necessary to develop symmetrical tools, i.e., the same tools for all co-workers; instead, the needs of each operator should be taken into account, according to the task he has to perform. In our case, the guides would be helped with perspective-taking aids, while the manipulators would be helped with action-oriented tools.