The cover image is based on the Review Review: materials and modelling for organic photovoltaic devices by Olivier Doat et al., https://doi.org/10.1002/pi.6280 .
The cover image, by Marco Rito‐Palomares et al., is based on the Perspective Monolithic chromatography: insights and practical perspectives, DOI: 10.1002/jctb.5040 .
Crack growth in sintering films constrained by a substrate, simulated using discrete element method. The simulations show the importance of inter‐particle sliding resistance in controlling defect formation and growth in constrained films. This may explain the experimentally observed differences in defect formation in constrained sintered films of different materials. Additional details in Figure 19 in the Feature article in this issue. Originally published in: C. L. Martin, H. Camacho‐Montes, L. Olmos, D. Bouvard, and R. K. Bordia, “Evolution of Defects During Sintering: Discrete Element Simulations”, J. Am. Ceram. Soc., 92 [7] 1435–41 (2009).
The scheme represents the formation of cementitious hydrates from the reaction of anhydrous cement with water and how the kinetics of this reaction can be affected by different types of additives, in particular by comb‐copolymers illustrated in the center of this scheme. Such polymers are widely used as dispersants in concrete to enhance its fluidity. More recently, they are playing an increasing role in enabling the production of concrete with a low environmental impact. However, the delay that they almost invariably cause to cement hydration represents a limitation to their use and to the development of alternative binding materials. The paper by Marchon et al. addresses this crucial scientific question and paves the way to the molecular design of optimized chemical admixtures. Cover Illustration by Fabian Rüdy and Stefan auf der Maur, Switzerland.
Detail of “Massacre des Innocents”, a stained glass (1150) from the western facade of the cathedral of Chartres (France), a UNESCO World Heritage monument. Of Romanesque style, it is among the oldest stained glasses preserved in the present building. It illustrates the “blue of Chartres”, a color originating from the presence of tetrahedral Co2+ and Fe2+ as reinforced by reducing fabrication conditions. See article ‘Spectroscopic Investigation of the Coloration and Fabrication Conditions of Medieval Blue Glasses’ by Myrtille Hunault et al. Photo courtesy Michel Herold‐Centre André Chastel.
Computed atomic structure of a metastable Σ 7m grain boundary of an Al2O3 bi‐crystal with yttrium atoms segregated to the grain boundary. Red, green and grey spheres denote oxygen, aluminum and yttrium atoms, respectively. The differently colouredpolyhedra highlight the various aluminum‐oxygen coordination in the grain boundary core region: the yellow tetrahedra mark fourfold‐coordinated Al atoms and the pyramidally shaped blue polyhedra indicate five‐fold coordinated Al atoms, while the usual six‐fold coordination of Al atom in bulk Al2O3 is identified with the green octahedra. The yttrium atoms in the boundary have eight oxygen neighbours and are also shown in greater detail in the pink polyhedra. The top view perspective shows clearly the inclination of the two single crystals against each other, and also highlights the high degree of atomic alignment when viewed along the [0001] direction. See feature article by Heuer et al.
The cover image, by Manal Ali et al., is based on the Research Article Potential of using non‐inoculated self‐aerated immobilized biomass reactor for post‐treatment of upflow anaerobic staged reactor treating high strength industrial wastewater, DOI: 10.1002/jctb.5082 .
