Search Results (6)

Galvanising pot roll bearings are subjected to severe deterioration due to the corrosion of the bearing materials in liquid Zn, resulting in maintenance stops that can cost thousands of pounds per hour in downtime. Dynamic wear testing in molten Zn-Al and Zn-Al-Mg was conducted to assess the corrosion and wear resistance of three material pairs using a bespoke testing rig. The materials investigated in this study were Wallex6^TM coated with WC-Co, stainless steel 316L coated with Al₂O₃, and as-received Wallex6^TM and Wallex4^TM alloys. It was found that only the Al₂O₃ coating remained unreactive in Zn alloy, whereas the materials containing Co were corroded, as evidenced by the formation of intermetallic compounds containing Al-Co-Zn-Fe. The results also highlighted that the dissolution of the Co matrix and diffusion of Zn and Al from the bath occurred in Wallex6^TM and Wallex4^TM. However, the diffusion of Zn into the Wallex^TM alloys was reduced by approximately 60% in the Zn-Al-Mg bath compared to Zn-Al. The wear scars were analysed to determine the wear coefficient of the worn specimens. Out of the three material couplings investigated in this study, minimal wear damage in both Zn-Al and Zn-Al-Mg was only obtained by pairing Wallex6^TM with Al₂O₃ coatings. Full article

Measles is a highly infectious disease leading to high morbidity and mortality impacting people’s lives and economies across the globe. The measles vaccine saves more lives than any other vaccine in the Essential Programme of Immunization and is also the most cost-effective vaccine, with an extremely high return on investment. This makes achieving measles elimination through vaccination a key child health intervention, particularly in low-income countries, where the overwhelming majority of measles deaths continue to occur. All countries and regions of the world have committed to achieving measles elimination, yet many have faced challenges securing political commitment at national and global levels and predictable, timely, and flexible support from global donors, and experienced setbacks during the COVID-19 pandemic. This has happened against a backdrop of stagnant measles vaccination coverage and declining enthusiasm for vertical programmes, culminating in a World Health Organization Strategic Advisory Group of Experts (WHO SAGE) review of the feasibility of measles eradication in 2019. Sustaining the elimination of measles long term is extremely difficult, and some countries have lost or nearly lost their measles elimination status in the face of ongoing importation of cases from neighbouring or closely connected countries in which elimination had been delayed. Thus, a widening equity gap in measles immunisation coverage creates challenges for all countries, not just those facing the greatest burden of measles morbidity and mortality. Delaying elimination of measles in some countries makes it cumulatively harder for all countries to succeed for three principal reasons: increased inequity in measles immunisation coverage makes outbreaks more likely to happen and to be larger; political will is very difficult to sustain; and immunity may wane to a point that transmission is re-established. New strategies are needed to support countries and regions in their vision for a world without measles, including ways to galvanise domestic, regional and global resources and ignite the political will that is essential to make the vision a reality. Full article

The production and quality of automotive-grade galvanised steel are affected by the limited service life of the pot roll bearings used in continuous galvanising lines. The journal bearings are subjected to severe degradation as they react with the molten Zn bath, and coatings can provide corrosion protection to the bearing materials. This research investigates the performance of Al₂O₃ coatings applied via the HVOF thermal spray process to stainless steel 316L substrates. Immersion tests were conducted in baths of different compositions, namely GI (Zn-0.3 wt.% Al) and ZMA (Zn-1.5 wt.% Al-1.5 wt.% Mg). Material characterisation after testing showed evidence of coating degradation after 1 week, as the coating tended to crack and detach from the substrate, allowing the molten Zn to attack the underlying steel. The coefficient of thermal expansion of Al₂O₃ and steel was measured, and a difference of 13 × 10⁻⁶ K⁻¹ was found, leading to the development of cracks in the coatings. Zn penetration through cracks was determined to be the main failure mechanism of the Al₂O₃ coatings, which otherwise remained inert to Zn-Al. Conversely, the coatings immersed in Zn-Al-Mg reacted with the Mg in the molten metal bath, showing that changing bath composition affected the performance of the coatings in molten Zn alloy. Full article

Ceramics are considered to be candidate materials for galvanising pot bearing materials due to their excellent corrosion resistance in many molten metals. Galvanising pot roll bearings must have excellent wear resistance, and, therefore, it is important to understand the wear behaviour of prospective bearing materials. This study investigates the friction- and wear-resistant properties of select ceramics, namely, pure hBN, BN M26, AlN-BN, Macor, 3YSZ, Al₂O₃ and Si₃N₄. The ceramics were tested at different sliding speeds using a pin-on-disc device equipped with SiC pins. The lowest coefficient of friction (COF) achieved was below 0.1, and it was measured for pure hBN at a 3.14 m/min sliding speed. However, a wear scar analysis showed that the BN grades suffered from severe wear. The highest wear rate was obtained for BN M26 at a 9.42 m/min sliding speed and was equal to 17.1 × 10⁻⁶ mm³ N⁻¹ m⁻¹. It was shown that the wear coefficient of the tested ceramics varied exponentially with hardness. The lowest wear was observed on the 3YSZ, Al₂O₃ and Si₃N₄ ceramics, which showed no volume loss, and, for this reason, they can be potentially used as bearing materials in continuous galvanising lines. Full article

The transition towards sustainable cities cannot be solved by individual stakeholders and organisations acting alone. Better governance for tackling such complex problems, including policy change and innovation adoption, will require purposeful collaboration. This is particularly evident in projects that involve integration across scales. Our case-study research compared six water-related innovations in large cities in Australia, the Netherlands, and the US. We found that government agencies, water utilities, professional organisations, and industry innovators were all vital actors, along with supportive community education. In the initiation phase of innovation, informal networks were used by sustainable innovation champions to galvanise support. As pilot projects emerged, more formal supportive processes and financial incentives were crucial. For large projects and for the mainstreaming of pilot projects, the role of formal coordination and integration mechanisms became vital for coherent and successful implementation. Various forms of network-based collaborative work were utilised, but the designation of a key coordinating organisation was found to be helpful in maintaining focus and momentum. Coordination activities across organisations, scales, and time were enhanced by the strength of core values and culture, such as valuing stakeholder engagement, innovation, flexibility, and having a focus on outcomes. Overall, this research demonstrated the need to continually evaluate the innovation process to ensure that key ingredients (suitable for each context) are implemented in a timely manner to strengthen the process and enable effective and purposeful collaboration. Full article

Higher education continues to play an integral role in fostering regional development and this is underpinned by the concept that universities possess a social responsibility as proponents of progress in relation to society’s socio-economic, political and environmental challenges. Different approaches have been articulated but none seems to provide a useful framework to support African universities’ contribution to development in their regions. This paper interrogates the idea of the ecological university and moves on to posit the possibility for a socio-ecological premise to meet environmental and societal needs, based on a symbiotic relationship between indigenous practices and a university’s capacity to engender sustainable development. Findings from an in-depth analysis of participants’ transcripts drawn from qualitative responses depict indigenous knowledge and practices which can galvanise environmental and societal sustainability, and bring to the fore the idea of the socio-ecologically-minded university. Full article