̽��ֱ�� of Cambridge - Darshil Shah

COP must reverse rising pessimism over building sector decarbonisation

ta385 — Thu, 17 Nov 2022 09:05:00 +0000

Negativity on Twitter about decarbonising the built environment has increased by around a third since 2014, according to a new analysis of more than 250,000 tweets featuring #emissions and #building between 2009 and 2021.

̽��ֱ��pessimistic trend has followed the launch of major climate action reports. ̽��ֱ��study, published in Nature Scientific Reports, reveals that expressions of ‘fear’ in Twitter dialogue increased by around 60% following the launch of the IPCC’s Fifth Assessment Report on Climate Change in 2015.

̽��ֱ��researchers, from Cambridge, Boston, Sussex and Aarhus Universities and Caltech, also found that ‘sadness’ increased by around 30% following the IPCC Special Report on Global Warming 1.5˚C in November 2019; while debate in November 2020 over lobbying of builders and utility companies over non-compliance with new building codes in the US triggered a spike in ‘anger’.

Mapping tweets that caused spikes in emotional engagement revealed that public concerns triangulated around inaction towards emission reduction, the fairness of carbon tax, the politicisation of building codes (distinctively seen for the US) and concerns over environmental degradation. This demonstrates, the researchers argue, “a strong environmental justice discourse.”

̽��ֱ��findings appear on the heels of COP27’s building sector events (10th – 14th November), which sought to promote a just transition and enhancing building resilience with the tagline ‘Build4Tomorrow’.

Lead author Ramit Debnath, Cambridge Zero Fellow at the ̽��ֱ�� of Cambridge and a visiting faculty associate in Computational Social Science at Caltech, said:

“Major climate policy events including COP have emphasised how difficult it is to decarbonise the built environment and this has been reflected in the rise of negative feelings on social media.

“But our research also offers hope – we found that climate policy events can and do foster public engagement, mostly positive, and that this has the power to increase the building sector’s focus on environmental justice.

“To build for tomorrow fairly, global climate action has to incorporate and empower diverse public voices. Policy actions are no longer isolated events in this digital age and demand two-way communication. Policy events and social media have a crucial role to play in this.”

̽��ֱ��study highlights that the building sector is one of the most important and challenging to decarbonise. ̽��ֱ��IPCC suggests that restricting climate change to 1.5˚C requires rapid and extensive changes around energy use, building design, and broader planning of cities and infrastructure. ̽��ֱ��buildings and construction sector currently accounts for around 39% of global energy and process-related carbon emissions. ̽��ֱ��International Energy Agency estimates that to achieve a net-zero carbon building stock by 2050, direct building carbon emissions must decrease by 50%, and indirect building sector emissions must also decrease 60% by 2030.

But decarbonising the building sector is challenging because it involves a complex overlap of people, places and practices that creates a barrier to designing just emission reduction policies. ̽��ֱ��study argues that democratising the decarbonisation process “remains a critical challenge across the local, national and regional scales”.

“Our findings shed light on potential pathways for a people-centric transition to a greener building sector in a net-zero future,” Debnath said.

Using advanced natural language processing and network theory, the researchers found a strong relationship between Twitter activity concerning the building sector and major policy events on climate change. They identify heightened Twitter engagement around developments including: the Paris Agreement’s call for the building sector to reduce its emissions through energy efficiency and address its whole life cycle; COP-23’s ’Human Settlement Day’ which focused on cities, affordable housing and climate action; COP25’s discourse on green/climate finance for residential homes; and COP26’s ’Cities, Region and Built environment Day’.

̽��ֱ��researchers found that despite negative sentiments gaining an increasing share since 2014, positive sentiments have continued to multiply as Twitter engagement has exploded. Across the entire study period (2009–21), positive sentiments have fairly consistently maintained a larger share of the conversation than negative sentiments.

̽��ֱ��study highlights the fact that core topics covered by tweets have changed significantly over time, as new innovations, technologies and issues have emerged. Hashtags associated with COP26, for instance, included #woodforgood and #masstimber, as well as #housingcrisis, #healthybuildings #scaleupnow, and #climatejusticenow, all largely or entirely absent in Twitter conversations between 2009 and 2016.

̽��ֱ��researchers found that discourse on innovative emissions reduction strategies which remain uncommon in the building sector— including use of alternate building materials like cross-laminated timber; implementing climate-sensitive building codes; and the circular economy – inspired Tweets expressing ‘anticipation’.

“COP26 was an extraordinary moment," Debnath said. " ̽��ֱ��Twitter engagement surrounding the event connected public health, the circular economy, affordable housing, and decarbonisation of the built environment like never before.”

“We are seeing a paradigm shift in the building emission discourse towards broader social and environmental justice contexts. Reference to low-carbon alternatives to concrete, housing crisis, scaling-up and climate justice are all part of the growing social justice movement associated with healthy and affordable social housing narratives globally.”

̽��ֱ��study notes that considering the size of Twitter’s current user base (around 211 million users globally), the number of tweets about emissions in the building sector, remains relatively small.

“It’s crucial that policymakers raise the salience of these issues and develop communications strategies to emphasise the importance of climate action in hard-to-decarbonise sectors like the building sector,” Debnath said.

̽��ֱ��authors of the study intend to continue to analyse social media interaction with further climate policy events, beginning with COP27.

Co-author Professor Benjamin Sovacool, Director of Institute for Global Sustainability at Boston ̽��ֱ�� said: “Some people dismiss Twitter as a poor focus of academic research, given its ability to spread misinformation and fake news. But we instead see it as a lens into the inner workings of how millions of people think, and rethink, about energy and climate change. It offers an incredible opportunity to reveal people’s true intentions, their revealed preferences, in unbiased form on a public forum.”

Co-author Prof R Michael Alvarez, Professor of Political and Computational Social Science at Caltech, said: “This is an innovative and important study, showing how an interdisciplinary and international group of scholars can use big data and machine learning to provide policy guidance on how to decarbonize the build sector. Research like this is critical at this time, to inform the debates at forums like COP27 and to energise additional scholarly work that can help further our goal of democratising climate action.”

Reference

R Debnath, R Bardhan, DU Shah, K Mohaddes, MH Ramage, MR Alvarez, and B Sovacool, ‘Social media enables people-centric climate action in the hard-to-decarbonise building sector’. Nature Scientific Reports (2022). DOI: 10.1038/s41589-022-23624-9

Social media engagement with climate policy events is vital to reducing building emissions and ensuring environmental justice, research led by Cambridge suggests

To build for tomorrow fairly, global climate action has to incorporate and empower diverse public voices

Ramit Debnath

Brian (Ziggy) Liloi. CC licence via Flickr

People installing a living roof in 2012

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Bamboo bats... Howzat?!

ta385 — Mon, 10 May 2021 05:00:00 +0000

Cricket bats should be made from bamboo rather than traditional willow, say researchers from Cambridge’s Centre for Natural Material Innovation. Extensive tests showed that bamboo performs better than willow as well as being more sustainable and cheaper.

Visualising heat flow in bamboo could help design more energy-efficient and fire-safe buildings

jg533 — Wed, 13 Nov 2019 10:00:00 +0000

̽��ֱ��building sector currently accounts for 30-40% of all carbon emissions, due to both the energy-intensive production of the materials (predominantly steel and concrete), and the energy used in heating and cooling the finished buildings. As the global population grows and becomes increasingly based in towns and cities, traditional building approaches are becoming unsustainable.

Renewable, plant-based materials such as bamboo have huge potential for sustainable and energy-efficient buildings. Their use would dramatically reduce emissions compared to traditional materials, helping to mitigate the human impact on climate change. This approach would also help keep carbon out of the atmosphere by diverting timber away from being burnt as fuel.

̽��ֱ��study involved scanning cross-sections of bamboo vascular tissue, the tissue that transports fluid and nutrients within the plant. ̽��ֱ��resulting images revealed an intricate fibre structure with alternating layers of thick and thin cell walls. Peaks of thermal conductivity within the bamboo structure coincide with the thicker walls, where chains of cellulose – the basic structural component of plant cell walls – are laid down almost parallel to the plant stem. These thicker layers also give bamboo its strength and stiffness. In contrast, the thinner cell walls have lower thermal conductivity due to cellulose chains being almost at a right angle to the plant stem.

“Nature is an amazing architect. Bamboo is structured in a really clever way,” said Darshil Shah, a researcher in Cambridge ̽��ֱ��’s Department of Architecture, who led the study. “It grows by one millimetre every ninety seconds, making it one of the fastest growing plant materials. Through the images we collected, we can see that it does this by generating a naturally cross-laminated fibre structure.”

While much research has been done on the cell structure of bamboo in relation to its mechanical properties, almost none has looked at how cell structure affects the thermal properties of the material. ̽��ֱ��amount of heating and cooling required in buildings is fundamentally related to the properties of the materials they are made from, particularly how much heat they conduct and store.

A better understanding of the thermal properties of bamboo provides insights into how to reduce the energy consumption of bamboo buildings. It also enables modelling of the way bamboo building components behave when exposed to fire, so that measures can be incorporated to make bamboo buildings safer.

“People may worry about fire safety of bamboo buildings,” said Shah. “To address this properly we have to understand the thermal properties of the building material. Through our work we can see that heat travels along the structure-supporting thick cell wall fibres in bamboo, so if exposed to the heat of a fire the bamboo might soften more quickly in the direction of those fibres. This helps us work out how to reinforce the building appropriately.”

At present, products such as laminated bamboo are most commonly used as flooring materials due to their hardness and durability. However, their stiffness and strength is comparable to engineered wood products, making them suitable for structural uses as well. “Cross-laminated timber is a popular choice of timber construction material. It’s made by gluing together layers of sawn timber, each at a right angle to the layer below,” said Shah. “Seeing this as a natural structure in bamboo fibres is inspiration for the development of better building products.”

̽��ֱ��team of researchers, from the ̽��ֱ�� of Cambridge and the ̽��ֱ�� of Natural Resources and Life Sciences Vienna, also plans to look at what happens to heat flow in bamboo when its surface is burned and forms char. ̽��ֱ��use of scanning thermal microscopy to visualise the intricate make-up of plants could also be useful in other areas of research, such as understanding how micro-structural changes in crop stems may cause them to fall over in the fields resulting in lost harvests.

Shah is a member of the ̽��ֱ�� of Cambridge’s interdisciplinary Centre for Natural Material Innovation, which aims to advance the use of timber in construction by modifying the tissue-scale properties of wood to make it more reliable under changing environmental conditions.

̽��ֱ��research was funded by the Leverhulme Trust, the Austrian Science Fund and the Lower Austrian Research and Education Society.

Reference
Shah, D.et al: “Mapping thermal conductivity across bamboo cell walls with scanning thermal microscopy.” Scientific Reports (2019). DOI: 10.1038/s41598-019-53079-4

Modified natural materials will be an essential component of a sustainable future, but first a detailed understanding of their properties is needed. ̽��ֱ��way heat flows across bamboo cell walls has been mapped using advanced scanning thermal microscopy, providing a new understanding of how variations in thermal conductivity are linked to the bamboo’s elegant structure. ̽��ֱ��findings, published in the journal Scientific Reports, will guide the development of more energy-efficient and fire-safe buildings, made from natural materials, in the future.

Nature is an amazing architect. Bamboo is structured in a really clever way.

Darshil Shah

Researcher profile: Dr Darshil Shah

Dr Darshil Shah is a Lecturer in the Department of Architecture who loves nature. “Nature is the master creator and architect!” he says. “My research is focused on how we can better use our natural resources to produce sustainable materials, which can be used in high-end and high-performance applications.”

He studied Mechanical Engineering with Mathematics at the ̽��ֱ�� of Nottingham, where a summer internship sparked his interest in real-world design.

“As an undergraduate student I had a fantastic opportunity to work on the design and manufacture of a five kilowatt wind turbine for the campus,” says Shah. “ ̽��ֱ��day we installed it was so exciting. It made me realise the impact my work could have, and the importance of joining together fundamental and applied research.”

Shah’s subsequent PhD, on the low-cost manufacture of wind turbine blades for small-scale turbines, led him to think about using greener materials to avoid the blades ending up in landfill at the end of their life. He also spent time in Oxford ̽��ֱ��’s Silk Group, where he learned about natural materials.

“My time at Oxford plunged me into a whole new world. I started thinking about how our materials and built environment could be informed and inspired by the natural world – from the beautiful silk threads and webs of spiders and silkworms, to the magnificent ivory tusks of elephants,” he says.

In Cambridge, Shah is exploring how to use a wide range of virgin and waste bioresources, such as timber, bamboo and waste date palm fibres, to help create sustainable products - from buildings to boats.

“At the fundamental level I’m exploring natural materials and structures for inspiration,” he says. “At the applied level, I’m working with industry to optimise materials for various sectors, from construction to transport.”

Shah believes that breaking boundaries between disciplines, particularly arts and humanities, and science and technology, is the only way to truly tackle some of the global challenges we face.

“Cambridge has a rich mix of brilliant researchers, thinkers and doers,” he says. “I’ve made connections in so many different departments, and had the chance to work on a fantastic variety of projects that I don’t think would have been possible anywhere else.”

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Green method developed for making artificial spider silk

sc604 — Mon, 10 Jul 2017 19:00:00 +0000

A team of architects and chemists from the ̽��ֱ�� of Cambridge has designed super-stretchy and strong fibres which are almost entirely composed of water, and could be used to make textiles, sensors and other materials. ̽��ֱ��fibres, which resemble miniature bungee cords as they can absorb large amounts of energy, are sustainable, non-toxic and can be made at room temperature.

This new method not only improves upon earlier methods of making synthetic spider silk, since it does not require high energy procedures or extensive use of harmful solvents, but it could substantially improve methods of making synthetic fibres of all kinds, since other types of synthetic fibres also rely on high-energy, toxic methods. ̽��ֱ��results are reported in the journal Proceedings of the National Academy of Sciences.

Spider silk is one of nature’s strongest materials, and scientists have been attempting to mimic its properties for a range of applications, with varying degrees of success. “We have yet to fully recreate the elegance with which spiders spin silk,” said co-author Dr Darshil Shah from Cambridge’s Department of Architecture.

̽��ֱ��fibres designed by the Cambridge team are “spun” from a soupy material called a hydrogel, which is 98% water. ̽��ֱ��remaining 2% of the hydrogel is made of silica and cellulose, both naturally available materials, held together in a network by barrel-shaped molecular “handcuffs” known as cucurbiturils. ̽��ֱ��chemical interactions between the different components enable long fibres to be pulled from the gel.

̽��ֱ��fibres are pulled from the hydrogel, forming long, extremely thin threads – a few millionths of a metre in diameter. After roughly 30 seconds, the water evaporates, leaving a fibre which is both strong and stretchy.

“Although our fibres are not as strong as the strongest spider silks, they can support stresses in the range of 100 to 150 megapascals, which is similar to other synthetic and natural silks,” said Shah. “However, our fibres are non-toxic and far less energy-intensive to make.”

̽��ֱ��fibres are capable of self-assembly at room temperature, and are held together by supramolecular host-guest chemistry, which relies on forces other than covalent bonds, where atoms share electrons.

“When you look at these fibres, you can see a range of different forces holding them together at different scales,” said Yuchao Wu, a PhD student in Cambridge’s Department of Chemistry, and the paper’s lead author. “It’s like a hierarchy that results in a complex combination of properties.”

̽��ֱ��strength of the fibres exceeds that of other synthetic fibres, such as cellulose-based viscose and artificial silks, as well as natural fibres such as human or animal hair.

In addition to its strength, the fibres also show very high damping capacity, meaning that they can absorb large amounts of energy, similar to a bungee cord. There are very few synthetic fibres which have this capacity, but high damping is one of the special characteristics of spider silk. ̽��ֱ��researchers found that the damping capacity in some cases even exceeded that of natural silks.

“We think that this method of making fibres could be a sustainable alternative to current manufacturing methods,” said Shah. ̽��ֱ��researchers plan to explore the chemistry of the fibres further, including making yarns and braided fibres.

This research is the result of a collaboration between the Melville Laboratory for Polymer Synthesis in the Department of Chemistry, led by Professor Oren Scherman; and the Centre for Natural Material Innovation in the Department of Architecture, led by Dr Michael Ramage. ̽��ֱ��two groups have a mutual interest in natural and nature-inspired materials, processes and their applications across different scales and disciplines.

̽��ֱ��research is supported by the UK Engineering and Physical Sciences Research Council (EPSRC) and the Leverhulme Trust.

Reference
Yuchao Wu et al. ‘Bioinspired supramolecular fibers drawn from a multiphase self-assembled hydrogel.’ Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1705380114

Researchers have designed a super stretchy, strong and sustainable material that mimics the qualities of spider silk, and is ‘spun’ from a material that is 98% water.

This method of making fibres could be a sustainable alternative to current manufacturing methods.

Darshil Shah

William Waterway

Spider web necklace with pearls of dew

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