Minor roads can also be difficult to cross. Can we rely on driver courtesy?

BACKGROUND: Crossing roads is the most problematic stage of walking trips, especially for older pedestrians. There is extensive research and a range of possible solutions in the case of busy roads. But quieter, minor roads can also be difficult to cross, if they are wide or vehicles move fast. This may lead people to suppress walking trips, limiting the benefits of active travel. Signalized or marked crossings increase safety but in minor roads they can lead to unnecessary delays for both pedestrians and vehicles. ‘Courtesy crossings’ are a compromise solution. Drivers are not legally required to stop but are encouraged to do so by the design of the crossing. But do drivers really stop for pedestrians at these crossings? For whom, when, and where? What types of designs are more effective in inducing courtesy? METHODS: We observed 937 driver/pedestrian interactions at 3 mandatory marked crossings (zebras/ marked crosswalks) and 17 courtesy crossings across England. The courtesy crossings had different combinations of four design elements: stripes (different from zebra stripes), coloured/textured road surface, visual narrowing of the road, and ramps. We modelled the effect of these elements on the probability of drivers stopping for pedestrians, controlling for the characteristics of pedestrians, vehicles, and roads. We also compared courtesy rates before and after the inclusion of a new design element (stripes) on an existing courtesy crossing. RESULTS: All four design elements increased the probability of drivers stopping for pedestrians, compared with a scenario without a crossing. The effect of each of the four elements was similar (odds ratio increase varying from 4.3 and 4.7, depending on the element). Some combinations of elements were even more effective than mandatory marked crossings. Courtesy behaviour was more likely when pedestrians crossed in groups, in roads with a median strip or low speed limit, close to junctions, and in areas with shops. There was more courtesy towards women but, surprisingly, age (elderly or children) and mobility restrictions were insignificant. Vehicle type, time of day, and day of week were also insignificant. Adding strips to an existing courtesy crossing increased courtesy rates from 20% to 97%. CONCLUSIONS: The use of multiple design elements increases the effectiveness of courtesy crossings but driver courtesy behaviour is also influenced by non-design characteristics. Adding courtesy crossings can be a solution to increase safety and promote walking trips in minor roads with low volumes of both motorized vehicles and pedestrians

The effect of Mg location on Co-Mg-Ru/γ-Al2O3 Fischer–Tropsch catalysts

© 2016 The Author(s) Published by the Royal Society. All rights reserved.The effectiveness of Mg as a promoter of Co-Ru/γ-Al2O3 Fischer-Tropsch catalysts depends on how and when the Mg is added. When the Mg is impregnated into the support before the Co and Ru addition, some Mg is incorporated into the support in the form of MgxAl2O3+x if the material is calcined at 550°C or 800°C after the impregnation, while the remainder is present as amorphous MgO/MgCO3 phases. After subsequent Co-Ru impregnation MgxCo3-xO4 is formed which decomposes on reduction, leading to Co(0) particles intimately mixed with Mg, as shown by high-resolution transmission electron microscopy. The process of impregnating Co into an Mg-modified support results in dissolution of the amorphous Mg, and it is this Mg which is then incorporated into MgxCo3-xO4. Acid washing or higher temperature calcination after Mg impregnation can remove most of this amorphous Mg, resulting in lower values of x in MgxCo3-xO4. Catalytic testing of these materials reveals that Mg incorporation into the Co oxide phase is severely detrimental to the site-Time yield, while Mg incorporation into the support may provide some enhancement of activity at high temperature

Characteristics of a gold-doped electrode for application in high-performance lithium-sulfur battery

Bulk sulfur incorporating 3 wt% gold nano-powder is investigated as possible candidate to maximize the fraction of active material in the Li-S battery cathode. The material is prepared via simple mixing of gold with molten sulfur at 120 °C, quenching at room temperature, and grinding. Our comprehensive study reports relevant electrochemical data, advanced X-ray computed tomography (CT) imaging of the positive and negative electrodes, and a thorough structural and morphological characterization of the S:Au 97:3 w/w composite. This cathode exhibits high rate capability within the range from C/10 to 1C, a maximum capacity above 1300 mAh gS−1, and capacity retention between 85% and 91% after 100 cycles at 1C and C/3 rates. The novel formulation enables a sulfur fraction in the composite cathode film as high as 78 wt%, an active material loading of 5.7 mg cm−2, and an electrolyte/sulfur (E/S) ratio of 5 μL mg−1, which lead to a maximum areal capacity of 5.4 mAh cm−2. X-ray CT at the micro- and nanoscale reveals the microstructural features of the positive electrode that favor fast conversion kinetics in the battery. Quantitative analysis of sulfur distribution in the porous cathode displays that electrodeposition during the initial cycle may trigger an activation process in the cell leading to improved performance. Furthermore, the tomography study reveals the characteristics of the lithium anode and the cell separator upon a galvanostatic test prolonged over 300 cycles at a 2C rate

The role of synthesis pathway on the microstructural characteristics of sulfur-carbon composites: X-ray imaging and electrochemistry in lithium battery

Two synthesis pathways are adopted to tune the microstructural characteristics of sulfur-carbon (S-C) composites for application in lithium-sulfur (Li-S) batteries. Both methods include intimate mixing of either carbon black or multiwalled carbon nanotubes with elemental sulfur, molten according to the first approach while dispersed in alcohol and heated according to the second one. Nano- and micro-scale X-ray computed tomography supported by X-ray diffraction and electron microscopy shows materials consisting of crystalline sulfur clusters (70 wt%) with size ranging from about 5 to 50 μm, surrounded by carbon. The sulfur cluster size appears limited by direct mixing of molten sulfur and carbons, in particular when carbon black is employed, whilst it is increased by exploiting the alcohol dispersion. Electrochemistry reveals that small sulfur particles lead to an improved rate capability in Li-S cells, whereas large active material domains may favor the capacity retention. The composites using carbon black nanoparticles exhibit the highest reversible capacity, with a maximum value exceeding 1500 mAh gS−1, whereas the composites involving multiwalled carbon nanotubes show the best capacity retention, with values approaching 70% over 150 cycles. Our multi-disciplinary approach will shed light on significant aspects aiming to enhance the Li-S battery and favor a practical application

Investigating lithium-ion battery materials during overcharge-induced thermal runaway: an operando and multi-scale X-ray CT study

Catastrophic failure of lithium-ion batteries occurs across multiple length scales and over very short time periods. A combination of high-speed operando tomography, thermal imaging and electrochemical measurements is used to probe the degradation mechanisms leading up to overcharge-induced thermal runaway of a LiCoO2 pouch cell, through its interrelated dynamic structural, thermal and electrical responses. Failure mechanisms across multiple length scales are explored using a post-mortem multi-scale tomography approach, revealing significant morphological and phase changes in the LiCoO2 electrode microstructure and location dependent degradation. This combined operando and multi-scale X-ray computed tomography (CT) technique is demonstrated as a comprehensive approach to understanding battery degradation and failure

Violent video games and morality: a meta-ethical approach

This paper considers what it is about violent video games that leads one reasonably minded person to declare "That is immoral" while another denies it. Three interpretations of video game content a re discussed: reductionist, narrow, and broad. It is argued that a broad interpretation is required for a moral objection to be justified. It is further argued that understanding the meaning of moral utterances – like "x is immoral" – is important to an understanding of why there is a lack of moral consensus when it comes to the content of violent video games. Constructive ecumenical expressivism is presented as a means of explaining what it is that we are doing when we make moral pronouncements and why, when it comes to video game content, differing moral attitudes abound. Constructive ecumenical expressivism is also presented as a means of illuminating what would be required for moral consensus to be achieved

Designing Engaging Learning Experiences in Programming

In this paper we describe work to investigate the creation of engaging programming learning experiences. Background research informed the design of four fieldwork studies to explore how programming tasks could be framed to motivate learners. Our empirical findings from these four field studies are summarized here, with a particular focus upon one – Whack a Mole – which compared the use of a physical interface with the use of a screen-based equivalent interface to obtain insights into what made for an engaging learning experience. Emotions reported by two sets of participant undergraduate students were analyzed, identifying the links between the emotions experienced during programming and their origin. Evidence was collected of the very positive emotions experienced by learners programming with a physical interface (Arduino) in comparison with a similar program developed using a screen-based equivalent interface. A follow-up study provided further evidence of the motivation of personalized design of programming tangible physical artefacts. Collating all the evidence led to the design of a set of ‘Learning Dimensions’ which may provide educators with insights to support key design decisions for the creation of engaging programming learning experiences

The Detection of Monoclinic Zirconia and Non-Uniform 3D Crystallographic Strain in a Re-Oxidized Ni-YSZ Solid Oxide Fuel Cell Anode

The solid oxide fuel cell (SOFC) anode is often composed of nickel (Ni) and yttria-stabilized zirconia (YSZ). The yttria is added in small quantities (e.g., 8 mol %) to maintain the crystallographic structure throughout the operating temperatures (e.g., room-temperature to >800 °C). The YSZ skeleton provides a constraining structural support that inhibits degradation mechanisms such as Ni agglomeration and thermal expansion miss-match between the anode and electrolyte layers. Within this structure, the Ni is deposited in the oxide form and then reduced during start-up; however, exposure to oxygen (e.g., during gasket failure) readily re-oxidizes the Ni back to NiO, impeding electrochemical performance and introducing complex structural stresses. In this work, we correlate lab-based X-ray computed tomography using zone plate focusing optics, with X-ray synchrotron diffraction computed tomography to explore the crystal structure of a partially re-oxidized Ni/NiO-YSZ electrode. These state-of-the-art techniques expose several novel findings: non-isotropic YSZ lattice distributions; the presence of monoclinic zirconia around the oxidation boundary; and metallic strain complications in the presence of variable yttria content. This work provides evidence that the reduction–oxidation processes may destabilize the YSZ structure, producing monoclinic zirconia and microscopic YSZ strain, which has implications upon the electrode’s mechanical integrity and thus lifetime of the SOFC

New zebrafish models of neurodegeneration

In modern biomedicine, the increasing need to develop experimental models to further our understanding of disease conditions and delineate innovative treatments has found in the zebrafish (Danio rerio) an experimental model, and indeed a valuable asset, to close the gap between in vitro and in vivo assays. Translation of ideas at a faster pace is vital in the field of neurodegeneration, with the attempt to slow or prevent the dramatic impact on the society's welfare being an essential priority. Our research group has pioneered the use of zebrafish to contribute to the quest for faster and improved understanding and treatment of neurodegeneration in concert with, and inspired by, many others who have primed the study of the zebrafish to understand and search for a cure for disorders of the nervous system. Aware of the many advantages this vertebrate model holds, here, we present an update on the recent zebrafish models available to study neurodegeneration with the goal of stimulating further interest and increasing the number of diseases and applications for which they can be exploited. We shall do so by citing and commenting on recent breakthroughs made possible via zebrafish, highlighting their benefits for the testing of therapeutics and dissecting of disease mechanisms

In-operando high-speed tomography of lithium-ion batteries during thermal runaway

Prevention and mitigation of thermal runaway presents one of the greatest challenges for the safe operation of lithium-ion batteries. Here, we demonstrate for the first time the application of high-speed synchrotron X-ray computed tomography and radiography, in conjunction with thermal imaging, to track the evolution of internal structural damage and thermal behaviour during initiation and propagation of thermal runaway in lithium-ion batteries. This diagnostic approach is applied to commercial lithium-ion batteries (LG 18650 NMC cells), yielding insights into key degradation modes including gas-induced delamination, electrode layer collapse and propagation of structural degradation. It is envisaged that the use of these techniques will lead to major improvements in the design of Li-ion batteries and their safety features