Café Scientifique

• Thursday 30 September 2021: Fairies photographed! The case of the Cottingley Fairies
• Thursday 28 October 2021: Green concrete: Building a more sustainable future
• Thursday 18 November 2021: Topic TBC
• Thursday 16 December 2021: Topic TBC
• Thursday 27 January 2022: Caught on camera: Reflections on William Hope and the Crewe Circle spirit photographs
• Thursday 17 February 2022: Topic TBC
• Thursday 24 March 2022: Topic TBC

Green Concrete: Building a More Sustainable Future

Professor Ashraf Ashour

Portland cement-based traditional concrete is the second most-used material globally, following water. However, the cement industry alone is responsible for ~8% of total human-driven CO₂ emissions, causing a serious environmental concern. Furthermore, current construction practice of materials’ overproduction, insufficient longevity of concrete structures and accumulation of construction and demolition waste (CDW) are wasteful of energy, creating serious environmental pollution and at high cost. The CDW industry is one of the largest global solid waste producers, accounting for 30-40% of total urban waste. In 2014, DEFRA reported that the UK generated 202.8m tons of waste, 59% of which came from CDW. 

In this talk, Ashraf Ashour will present the UK-Turkey research project which won the 2020 Newton Prize-2020 with Turkey to tackle the drawbacks of concrete production and CDW. He will be looking at the production of 100% CDW-based cement-free ‘green’ concretes (CDW-based geopolymer binders and recycled aggregates) to be incorporated in the development of LEGO-like/demountable structural elements, facilitating the future reuse of structural elements at the end of their life, potentially achieving more than 50% reduction in the embodied energy of structures as well as giving clients the benefit of retaining the value of their assets.

Ashraf Ashour is a Professor of Structural Engineering at the University of Bradford, received his PhD from Cambridge University, and is a Fellow of the Institution of Structural Engineers (FIStructE). In 2020, he was ranked among the top 2% scientists in civil engineering.

Caught on Camera: Reflections on William Hope and the Crewe Circle Spirit Photographs

Dr Efram Sera-Shriar

During the opening decades of the 20th century, William Hope was a well-respected medium amongst the spiritualist community in Britain, with positive endorsements from major scientific figures such as the chemist William Crookes and the author and physician Arthur Conan Doyle. He was often seen as one of the few mediums to be able to produce authentic spirit photographs.

However, all that changed in late February of 1922 when a team of investigators led by the famous British psychical researcher Harry Price claimed to have caught Hope cheating during one of his sittings and discovered that he was swapping blank photographic plates with ones containing existing images on them that appeared to be depictions of spirit entities. Hope was publicly exposed as a fraud, and what ensued was a major debate between believers and sceptics over the legitimacy of the medium’s alleged spirit photography.

Using surviving materials from the Senate House Library and Science Museum Group collections, including photographs, private correspondence, published sources, and camera technologies, this talk will explore this story, and reflect on what makes for trustworthy evidence in investigations of extraordinary phenomena.