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Women in STEM: Holly Pacey

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My ambition to have a career in physics research began when I was at school. I grew up in Nottingham, where my Dad was the main homemaker and worked from home; and my Mum worked in a hospital pharmacy. I attended my local comprehensive and sixth form before moving to Cambridge to study Natural Sciences at King’s College.

I spent two summers working in the Cambridge Institute of Astronomy, and this sparked a desire to work in particle physics. After graduating with my MSc, I began working towards a PhD in high energy physics with the ATLAS experiment. What strikes me most about the environment in Cambridge, compared to other institutions, is the atmosphere of collaboration. Improving your understanding of your subject and exploring new and creative research ideas with everyone in the group is always prioritised above rank – there is no such thing as a stupid question here.

Having the opportunity to work with CERN is incredible. The diversity of people, with a huge range of ideas, all working towards a common goal is very inspiring. The calibre of research at both institutions motivates you to become the best researcher you can, but with enough support that you aren’t overwhelmed.

On a grand scale, my field is trying to understand what the universe is made of at a fundamental level. We are looking at how the constituent parts – called particles - can interact and combine to take us from the high energy Big Bang to the universe we see today. My research aims to find evidence for new particles in the data taken with the ATLAS detector at the Large Hadron Collider, which would allow our current Standard Model of particle physics to be extended. For example, I have focused on searches for new particles predicted by a model called Supersymmetry, currently the most popular extension to the standard model that could explain phenomena such as dark matter.

A key moment for me was attending my first ATLAS conference focusing on the collaboration of the different new-physics groups. The many innovative analysis techniques being presented were very interesting and I learned a lot in the plentiful discussions, both about the work I had contributed to the conference and that of others. In the long term, I hope my research will contribute to our understanding of the universe, and lead to an exciting career in academia.

Part of my research involves reconstructing ‘missing’ particles that ATLAS isn’t designed to detect. These are either neutrinos or new physics particles and measuring them well involves carefully balancing all aspects of the detector. Generally, I spend my days doing data analysis. This can involve using computer simulations of background and signal events, using statistics and techniques like machine learning techniques to optimise where to look in the data to find new physics.

My most interesting project so far is a new project looking for signs of new physics or behaviour in a data-data comparison of oppositely charged electron-muon events. This idea is very exciting, as a deviation from the Standard Model expectation could be explained by many different new models. It also doesn’t rely on simulated data, which is getting more important now that ATLAS has taken such vast amounts of data that simulation is struggling to keep up computationally.

If you are passionate about a subject and have the drive to work hard on it then that should speak for itself. There will be challenges in your career whatever you choose to do, but the more women that follow their ambitions into STEM now, the easier it will be for the next generation of aspiring scientists.

Holly Pacey is a PhD candidate in the High Energy Physics Group based at the Cavendish Laboratory, and works on the ATLAS experiment. She spent the 2017-18 academic year working at CERN in Geneva, which operates the largest particle physics laboratory in the world. 

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Women in STEM: Dr Anita Faul

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I think the most fun I’ve probably had at work was when I programmed a movable camera to follow me around the room. I’m a mathematician by training and now work as a Teaching Associate in Scientific Computing, specialising in algorithms. I will soon be starting at the British Antarctic Survey as a Data Scientist, to which I am immensely looking forward to.

Artificial Intelligence and Machine Learning are very popular now. These are also algorithms, with the difference that often the numbers are interpreted as probabilities. So computers do not necessarily give an exact answer, but the answer that is the most probable in some setting.  Computer vision has developed a lot in recent years. I've also worked in industry on various applications and particularly enjoy making connections between different fields. The challenge is to express the problem in mathematical terms. Then it can be tackled by algorithms.

With human learning, experiences change how we interpret our world. A levitation act will not fascinate a small child if it has not learned about gravity yet. Once it knows about gravity, it does seem to like throwing things down again and again, as any frustrated parent will tell you!  Similarly, machine learning lets the computer have experiences in the form of data - lots and lots of data. While a human child can distinguish between a cat and a dog after seeing a few examples, a computer needs far more.

The most important question is not how a computer arrives at a result, but why. Deep neural networks have had great success lately. However, their structure is so complex that a human cannot understand how they arrived at their answer. How can we then trust the answer? This can also lead to computers being easily fooled where a human would not be. This is something else that we don’t yet understand why. I'm interested in developing algorithms which are self-improving, learning from new data.

The students are my teachers. They ask interesting, challenging questions. It is best to be open, if I do not know the answer, and go on a journey of discovery together. I might not know it, but I surely will find out. Students learn in different ways and I enjoy the challenge to find ways to make a topic accessible. Artificial intelligence makes the headlines often enough to be able to remain topical.

Collaborations are easy if one is willing. A lot of high tech companies working in this field have settled in Cambridge or have opened offices here. Additionally, exciting research is conducted in many departments across Cambridge using machine learning techniques. I enjoy pointing these out to the students who can then see what they have learned in action. 

Have a go, you never know what you might achieve. When I was 15, I took part in a maths competition aimed at pupils two years above me at school, since my brother took part. I placed higher than him. He bore it gracefully. For me, it was a start to more and more opportunities opening up. If you do not try, you cannot succeed. Yes, there is failure, but then one readjusts and carries on. Lately, I have become more interested in post-graduate education in general, policies and procedures, funding and finances. The information is too dispersed, especially for those considering a post-graduate degree. I'm working on linking different sources of information. 

Dr Anita Faul is a Teaching Associate at the Cavendish Laboratory and a Fellow of Selwyn College, where she specialises in algorithms. Here, she tells us about what it's like to teach at Cambridge and whether we can trust the answers that computers give us. 

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Colour-changing artificial ‘chameleon skin’ powered by nanomachines

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The material, developed by researchers from the University of Cambridge, is made of tiny particles of gold coated in a polymer shell, and then squeezed into microdroplets of water in oil. When exposed to heat or light, the particles stick together, changing the colour of the material. The results are reported in the journal Advanced Optical Materials.

In nature, animals such as chameleons and cuttlefish are able to change colour thanks to chromatophores: skin cells with contractile fibres that move pigments around. The pigments are spread out to show their colour, or squeezed together to make the cell clear.

The artificial chromatophores developed by the Cambridge researchers are built on the same principle, but instead of contractile fibres, their colour-changing abilities rely on light-powered nano-mechanisms, and the ‘cells’ are microscopic drops of water.

When the material is heated above 32C, the nanoparticles store large amounts of elastic energy in a fraction of a second, as the polymer coatings expel all the water and collapse. This has the effect of forcing the nanoparticles to bind together into tight clusters. When the material is cooled, the polymers take on water and expand, and the gold nanoparticles are strongly and quickly pushed apart, like a spring.

“Loading the nanoparticles into the microdroplets allows us to control the shape and size of the clusters, giving us dramatic colour changes,” said Dr Andrew Salmon from Cambridge’s Cavendish Laboratory, the study’s co-first author.

The geometry of the nanoparticles when they bind into clusters determines which colour they appear as: when the nanoparticles are spread apart they are red and when they cluster together they are dark blue. However, the droplets of water also compress the particle clusters, causing them to shadow each other and make the clustered state nearly transparent.

At the moment, the material developed by the Cambridge researchers is in a single layer, so is only able to change to a single colour. However, different nanoparticle materials and shapes could be used in extra layers to make a fully dynamic material, like real chameleon skin.

The researchers also observed that the artificial cells can ‘swim’ in simple ways, similar to the algae Volvox. Shining a light on one edge of the droplets causes the surface to peel towards the light, pushing it forward. Under stronger illumination, high pressure bubbles briefly form to push the droplets along a surface.

“This work is a big advance in using nanoscale technology to do biomimicry,” said co-author Sean Cormier. “We’re now working to replicate this on roll-to-roll films so that we can make metres of colour changing sheets. Using structured light we also plan to use the light-triggered swimming to ‘herd’ droplets. It will be really exciting to see what collective behaviours are generated.”

The research was funded by the European Research Council (ERC) and the Engineering and Physical Sciences Research Council (EPSRC).

Reference:
Andrew R Salmon et al. ‘Motile Artificial Chromatophores: Light-Triggered Nanoparticles for Microdroplet Locomotion and Color Change.’ Advanced Optical Materials (2019). DOI: 10.1002/adom.201900951

Researchers have developed artificial ‘chameleon skin’ that changes colour when exposed to light and could be used in applications such as active camouflage and large-scale dynamic displays.

This work is a big advance in using nanoscale technology to do biomimicry
Sean Cormier

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Women in STEM: Verity Allan

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I came to Cambridge from a town in the Midlands to study Anglo-Saxon, Norse and Celtic. My parents were the first in their families to go to university, and I was the first in my extended family to get an Oxbridge degree. I then tried to get a doctorate from Oxford, but this didn't go to plan - I eventually left with an MLitt and an urgent need to get a job.

While job hunting I realised that the really interesting jobs required a numerate degree. So, I enrolled at The Open University to study Computing and Mathematical Sciences. I graduated with a First Class Honours degree five years later. While I was studying I got my first job in tech, doing tech support and technical writing for CARET, a technology innovation unit within Cambridge University. I then expanded my range and starting to do technical management work and software testing, before I moved on to my current job.

Retraining is totally a thing. It's not as easy to do as it was when I did it as a result of the changes to funding and costs for part-time degrees. However, there are now a whole bunch of MOOCs out there, some of which offer qualifications at a more reasonable fee. But retraining opens a whole lot of opportunities in fields where you're likely to find some really interesting questions to work on or interesting projects to support. There are a lot of jobs in science that need project management and communications experience but that don't require you to do top-level research.

I’m now part of the group writing software for Square Kilometre Array (SKA) project. This will be the world’s largest radio telescope, and I’m part of the team that is designing the supercomputer to do data processing for it. We are producing an architecture for this computer, and testing whether this architecture will work by writing and running prototype code. I get to work with people all over the world.

This is a very interesting project to work on - it is stretching the limits of what a radio telescope can do. It's also exploring the limits of what can be done computationally; it requires a completely new way of dealing with astronomy data because there's just so much of it. I also do research as part of my PhD, which is aimed at providing astronomy researchers with a tool-kit for interacting with the ridiculous amounts of data that will be produced by the SKA and other next-generation telescopes.

My work is pretty varied. It involves some research, some programming, some technical project management; and maintaining the collaborative tools used by the project I work on. I also maintain the wiki, the ticket tracking system (we use this so we have some way of recording what work needs to be done), and manage the code repositories for the project. (These days, I delegate a lot of this.) I also managed the formal documentation for the Science Data Processor (SDP) project. As I've learned more, I started chairing technical meetings - I did the project management for the SDP architecture work, and for one of the key software components of the SDP. This involves tracking work, helping people fix problems, note-taking, and helping people work out what's going well and what's not. As part of the architecture team, I also read our documentation, to ensure it makes sense and check that it says what we think it says. As the project has developed, I’ve done more programming and policy development. I go fairly often to the headquarters of the SKA at Jodrell Bank in Cheshire. I've also travelled to South Africa (where one of the SKA telescopes will be built), and to the Netherlands and Malta for SDP Conferences.

I have an ‘academic-related’ support position, but I'm also doing a PhD as part of my job. This involves a lot of meetings, usually teleconferences, a lot of email, and a lot of writing (because if you don't write something down in an international project, it doesn't exist). Cambridge is a great place to be doing my PhD work, because I'm part of an active community of scholars working in my field, and in adjacent areas. The University leads the work on the supercomputer for the SKA, so we are a hub for a lot of international activity. The University also has a Top 100 supercomputer, so I have access to world-leading infrastructure for my work, as well as a specialist platform developed for the SKA, P3-Alaska.

At the start of my PhD I visited Lord's Bridge, the location of the Mullard Radio Astronomy Observatory, with other first year PhD students. This is a fascinating site - there are traces all around of how the site was used as an ammunition store during the Second World War. Since the war, it's been used as a radio astronomy observatory, and you can see parts of several radio telescopes that had key roles in understanding the radio sky, winning Nobel Prizes in the process. (You can see the remains of the array that Dame Jocelyn Bell Burnell used to discover pulsars.) Now the site is used primarily as a testbed for new technology for radio telescopes - there are test antennas there for the HERA project, and for the SKA. But you can see dishes and equipment that describe the history of radio astronomy and interferometry. As a personal project, I’m also finding out about the women who were “computers” in the Cavendish Laboratory, and the programming techniques they used.

Being diagnosed with a serious stress-related health condition meant I had to learn how to refactor my life to allow me to do what I want to do. This is a big part of my life that required major work to come to terms with. There are many compromises I have had to make in order to recover and be able to work full time. This includes discovering new things that can make my condition worse, and finding new ways to manage that. I rely on the support of my line manager to help keep things ticking over OK. 

It’s important to be aware that in physics, computing, and mathematics, at the moment, women will have to get used to being in a minority. I am quite often the only woman or non-binary person in the room - this is something that's changing, but it is currently the case. This is compounded if you’re also a member of another marginalised group. However, there are lots of networks you can join in order to deal with the sensation of being outnumbered. Finally, just because you're finding the maths or science difficult doesn't mean that you're no good at it. Often, it will be hard, but as you work further, stuff that was previously hard will become quite easy to use. You don't have to understand this stuff instantly to be able to make a useful contribution.

 

 

Verity Allan is a graduate of Cambridge, Oxford, and The Open University. She is a PhD candidate at the Cavendish Laboratory and works as a project manager and programmer on the software for the Square Kilometre Array, the world's largest radio telescope.

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AI learns the language of chemistry to predict how to make medicines

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University of Cambridge researchers have shown that an algorithm can predict the outcomes of complex chemical reactions with over 90% accuracy, outperforming trained chemists. The algorithm also shows chemists how to make target compounds, providing the chemical ‘map’ to the desired destination. The results are reported in two studies in the journals ACS Central Science and Chemical Communications.                                            

A central challenge in drug discovery and materials science is finding ways to make complicated organic molecules by chemically joining together simpler building blocks. The problem is that those building blocks often react in unexpected ways.

“Making molecules is often described as an art realised with trial-and-error experimentation because our understanding of chemical reactivity is far from complete,” said Dr Alpha Lee from Cambridge’s Cavendish Laboratory, who led the studies. “Machine learning algorithms can have a better understanding of chemistry because they distil patterns of reactivity from millions of published chemical reactions, something that a chemist cannot do.”                                                                                                                                             

The algorithm developed by Lee and his group uses tools in pattern recognition to recognise how chemical groups in molecules react, by training the model on millions of reactions published in patents.

The researchers looked at chemical reaction prediction as a machine translation problem. The reacting molecules are considered as one ‘language,’ while the product is considered as a different language. The model then uses the patterns in the text to learn how to ‘translate’ between the two languages.

Using this approach, the model achieves 90% accuracy in predicting the correct product of unseen chemical reactions, whereas the accuracy of trained human chemists is around 80%. The researchers say that the model is accurate enough to detect errors in the data and correctly predict a plethora of difficult reactions.

The model also knows what it doesn’t know. It produces an uncertainty score, which eliminates incorrect predictions with 89% accuracy. As experiments are time-consuming, accurate prediction is crucial to avoid pursuing expensive experimental pathways that eventually end in failure.

In the second study, Lee and his group, collaborating with the biopharmaceutical company Pfizer, demonstrated the practical potential of the method in drug discovery.

The researchers showed that when trained on published chemistry research, the model can make accurate predictions of reactions based on lab notebooks, showing that the model has learned the rules of chemistry and can apply it to drug discovery settings.

The team also showed that the model can predict sequences of reactions that would lead to a desired product. They applied this methodology to diverse drug-like molecules, showing that the steps that it predicts are chemically reasonable. This technology can significantly reduce the time of preclinical drug discovery because it provides medicinal chemists with a blueprint of where to begin.

“Our platform is like a GPS for chemistry,” said Lee, who is also a Research Fellow at St Catharine’s College. “It informs chemists whether a reaction is a go or a no-go, and how to navigate reaction routes to make a new molecule.”

The Cambridge researchers are currently using this reaction prediction technology to develop a complete platform that bridges the design-make-test cycle in drug discovery and materials discovery: predicting promising bioactive molecules, ways to make those complex organic molecules, and selecting the experiments that are the most informative. The researchers are now working on extracting chemical insights from the model, attempting to understand what it has learned that humans have not.

“We can potentially make a lot of progress in chemistry if we learn what kinds of patterns the model is looking at to make a prediction,” said Peter Bolgar, a PhD student in synthetic organic chemistry involved in both studies. “The model and human chemists together would become extremely powerful in designing experiments, more than each would be without the other.”

The research was supported by the Winton Programme for the Physics of Sustainability and the Herchel Smith Fund.

References:
Philippe Schwaller et al. ‘Molecular Transformer: A Model for Uncertainty-Calibrated Chemical Reaction Prediction.’ ACS Central Science (2019). DOI: 10.1021/acscentsci.9b00576

Alpha Lee et al. ‘Molecular Transformer unifies reaction prediction and retrosynthesis across pharma chemical space.’ Chemical Communications (2019). DOI: 10.1039/C9CC05122H

 

Researchers have designed a machine learning algorithm that predicts the outcome of chemical reactions with much higher accuracy than trained chemists and suggests ways to make complex molecules, removing a significant hurdle in drug discovery.

Our platform is like a GPS for chemistry
Alpha Lee
Background abstract line

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Young leaders from UK and Latin America tackle future at Shaping Horizons

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They will explore how emerging technologies like those underpinning genomics, AI, clean energy, and smart cities can be used and regulated to create a more equitable and sustainable global community as well as how to encourage sustainable leadership across disciplines and move beyond traditional diplomacy to address global challenges like climate change and social inequalities.

Shaping Horizons 2019 is a Summit and Action Programme rooted in science, policy, and innovation and will strengthen ties and build relationships between young Future Leaders and Senior Leaders from the UK and Latin America. The delegates have been selected from across academia, industry, and government.

Prof. David Cardwell, FREng, Pro-Vice-Chancellor for Strategy and Planning at the University of Cambridge, welcomed delegates at the start of the Summit on behalf of the University.

“On every front, the University has been and continues to be engaged with Latin America, including the pleasure of hosting this fantastic summit, Shaping Horizons, where the mission is to empower and promote youth, create networks and to drive change,” Cardwell said.

The week will culminate with the Future Leaders pitching for prize money to support their own innovative social impact projects they have developed through mentorship and learning during the Summit.

Winners will be supported in further developing and launching their projects through the Action Programme which will follow on from the Summit.

  

Nigel Baker, OBE MVO, Head of the Latin America Department at the Foreign and Commonwealth Office told delegates that all their ideas would help shape the future.

“Shaping Horizons is absolutely driven by the sense of entrepreneurship, innovation, and ideas of the young people involved. It is going to be fascinating to see the proposals that are coming out,” Baker said.

“There are 24 different teams and there are going to be some spectacular proposals and ideas. Some will win prizes, some will not, but I suspect that all of those ideas are going to be applicable in the future.”

Shaping Horizons is a non-profit initiative organised at the University of Cambridge with the support of the Office of Postdoctoral Affairs, and the Cambridge Hub of Global Shapers Community, which is an initiative of the World Economic Forum.

Shaping Horizons was founded by Dr. Matias Acosta, a UK-Canada Fellow at the Centre for Science and Policy, and Theo Lundberg, a NanoDTC PhD Student in the Department of Physics.

“Shaping Horizons was founded to promote sustainability using global, cross-disciplinary cooperation as our driving force,” Acosta said.

“We are a team of 40 undergraduates and academics from across more than 20 departments from the University of Cambridge bringing this initiative forward. Our goal is to build a shared and sustainable future between Latin America and the UK.

"We will be providing more than £30,000 in support for cooperative bilateral projects and also have designed a continuous mentorship programme to maximize the chance of success of each of the ideas.”

More than 100 future leaders from the UK and Latin America have gathered at the University of Cambridge to discuss the future of work and education in an increasingly global digital era at this year’s Shaping Horizons summit.

Shaping Horizons was founded to promote sustainability using global, cross-disciplinary cooperation as our driving force
Shaping Horizons founder Dr. Matias Acosta

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Yes

Cambridge vs climate change | Vice-Chancellor's blog

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Weather board at Cambridge University Botanic Garden showing data for 25 July 2019

In July this year, staff at the Cambridge University Botanic Garden registered the United Kingdom’s highest ever temperature: 38.7° C. Temperatures in the glasshouses rose to an unbearable 45° C. It is clear that far from being a unique occurrence, this is part of an evolving pattern. It is widely agreed that in the future we will have to contend with increasingly frequent extreme weather events. Climate change is real, and it is happening here and now.

Today sees the beginning of a global week of action on climate change. Around the world, schoolchildren, parents, teachers, environmental campaigners and concerned citizens will be gathering to raise awareness of the dangers posed by climate change. Here in Cambridge, and with the University’s full support, students and members of staff will be among the demonstrators urging policy-makers to heed the advice of the scientific community.

Part of our responsibility as a globally influential academic institution is to take a leading role in helping our society move towards a sustainable future. As young people take to the streets, it is worth reflecting on what the University of Cambridge is doing to mitigate the environmental threat.

Cambridge chemists and physicists are developing next-generation batteries and solar cells – both of which are vital in the transition to a low-carbon economy. Our engineers are supporting the delivery of electric forms of transport that will be essential for the UK to meet its decarbonisation targets. The Cambridge Creative Circular Plastics Centre is developing methods to eliminate plastic waste.

Flood defences

From working with local communities to improve flood defences along the eastern coast, or alerting us to the increased pace of melting glaciers, to identifying populations who are most likely to shoulder the burden of climate change, our researchers are already deeply invested in helping us better understand the multifaceted nature of the challenge.

Our researchers are not only developing greener fuels, better technologies and more sustainable materials, but addressing all aspects of a zero-carbon future: the impact it will have on what we eat, how we work, how we travel, the way we communicate, how we measure economic progress and the way our societies are organised. Crucially, they are producing the knowledge to ensure that policy decisions are based on the best available evidence.

These academic efforts – arguably the greatest contribution we can make to tackling climate change – are backed up by action within the University itself, as we continue to implement the recommendations made by the Divestment Working Group in 2018.

We are leading by example, and demonstrating what is achievable. Our Sustainable Food Policy, launched in 2016, has already reduced food-related carbon emissions from our catering service by a third, and has been widely held up as an example for large institutions.

 

More recently, Cambridge became the first university in the world to announce that it has adopted a science-based target for decarbonisation, committing itself to a 75% decrease of its 2015 energy-related carbon emissions by 2030, and to reducing them to absolute zero by 2048. We are working with local authorities to plan a future that offers staff practical and affordable ways of travelling sustainably to and from work. Through our Green Impact programmewe will be seeking ideas from students and staff on how we can accelerate our decarbonisation.

New initiative

Later this term, we will be formally launching a major new initiative, led by Dr Emily Shuckburgh, harnessing the full breadth of the University’s research and teaching capabilities to respond to climate change and support the transition to a sustainable future, both in the UK and globally.  

The new initiative will develop a bold programme of education, research, demonstration projects and knowledge exchange focused on supporting a zero carbon world. Its ambition is to generate and disseminate the ideas and innovations that will shape our future – and to equip a future generation of leaders with the skills to navigate the global challenges of the coming decades.

It is being launched only a few months after the UK became the first major world economy to legislate for net zero emissions. Eliminating greenhouse gas emissions by 2050 will mean a fundamental change over the coming decades in all aspects of our economy, including how we generate energy, and how we build decarbonisation into policy and investment.

Through the initiative we will engage in active collaboration with other universities and research institutes in the UK and beyond, including the newly established Global Universities Alliance on Climate.

Unite behind the science

As the world’s leaders gather in Chile later this year for the latest round of climate change talks, the University will be decisively setting out its stall to demonstrate how it contributes to tackling this most pressing of global challenges.

I am encouraged by the younger generations’ determination to make their voices heard on the key issue of climate change. I am especially struck by the rallying cry from that remarkable activist, Greta Thunberg, to “unite behind the science”, and to put “the best available science [at] the heart of politics”.

That is exactly what Cambridge is determined to do – not only on this day of climate action, or even this week, but for the long term.

The Vice-Chancellor, Professor Stephen J Toope kicks off a global day of action with a discussion on the University’s efforts to tackle climate change.

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Yes

Quantum state of single electrons controlled by ‘surfing’ on sound waves

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The international team, including researchers from the University of Cambridge, sent high-frequency sound waves across a modified semiconductor device to direct the behaviour of a single electron, with efficiencies in excess of 99%. The results are reported in the journal Nature Communications.

A quantum computer would be able to solve previously unsolvable computational problems by taking advantage of the strange behaviour of particles at the subatomic scale, and quantum phenomena such as entanglement and superposition. However, precisely controlling the behaviour of quantum particles is a mammoth task.

“What would make a quantum computer so powerful is its ability to scale exponentially,” said co-author Hugo Lepage, a PhD candidate in Cambridge’s Cavendish Laboratory, who performed the theoretical work for the current study. “In a classical computer, to double the amount of information you have to double the number of bits. But in a quantum computer, you’d only need to add one more quantum bit, or qubit, to double the information.”

Last month, researchers from Google claimed to have reached ‘quantum supremacy’, the point at which a quantum computer can perform calculations beyond the capacity of the most powerful supercomputers. However, the quantum computers which Google, IBM and others are developing are based on superconducting loops, which are complex circuits and, like all quantum systems, are highly fragile.

“The smallest fluctuation or deviation will corrupt the quantum information contained in the phases and currents of the loops,” said Lepage. “This is still very new technology and expansion beyond the intermediate scale may require us to go down to the single particle level.”

Instead of superconducting loops, the quantum information in the quantum computer Lepage and his colleagues are devising use the ‘spin’ of an electron – its inherent angular momentum, which can be up or down – to store quantum information.

“Harnessing spin to power a functioning quantum computer is a more scalable approach than using superconductivity, and we believe that using spin could lead to a quantum computer which is far more robust, since spin interactions are set by the laws of nature,” said Lepage.

Using spin allows the quantum information to be more easily integrated with existing systems. The device developed in the current work is based on widely-used semiconductors with some minor modifications.

The device, which was tested experimentally by Lepage’s co-authors from the Institut Néel, measures just a few millionths of a metre long. The researchers laid metallic gates over a semiconductor and applied a voltage, which generated a complex electric field. The researchers then directed high-frequency sound waves over the device, causing it to vibrate and distort, like a tiny earthquake. As the sound waves propagate, they trap the electrons, pushing them through the device in a very precise way, as if the electrons are ‘surfing’ on the sound waves.

The researchers were able to control the behaviour of a single electron with 99.5% efficiency. “To control a single electron in this way is already difficult, but to get to a point where we can have a working quantum computer, we need to be able to control multiple electrons, which get exponentially more difficult as the qubits start to interact with each other,” said Lepage.

In the coming months, the researchers will begin testing the device with multiple electrons, which would bring a working quantum computer another step closer.

The research was funded in part by the European Union’s Horizon 2020 programme.

Reference:
Shintaro Takada et al. ‘Sound-driven single-electron transfer in a circuit of coupled quantum rails.’ Nature Communications (2019). DOI:10.1038/s41467-019-12514-w

 

Researchers have successfully used sound waves to control quantum information in a single electron, a significant step towards efficient, robust quantum computers made from semiconductors.

We believe that using spin could lead to a quantum computer which is far more robust, since spin interactions are set by the laws of nature
Hugo Lepage
3D render of the semiconductor nanostructure

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‘Messy’ production of perovskite material increases solar cell efficiency

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Scientists at the University of Cambridge studying perovskite materials for next-generation solar cells and flexible LEDs have discovered that they can be more efficient when their chemical compositions are less ordered, vastly simplifying production processes and lowering cost.

The surprising findings, published in Nature Photonics, are the result of a collaborative project, led by Dr Felix Deschler and Dr Sam Stranks.

The most commonly used material for producing solar panels is crystalline silicon, but to achieve efficient energy conversion requires an expensive and time-consuming production process. The silicon material needs to have a highly ordered wafer structure and is very sensitive to any impurities, such as dust, so has to be made in a cleanroom.

In the last decade, perovskite materials have emerged as promising alternatives.

The lead salts used to make them are much more abundant and cheaper to produce than crystalline silicon, and they can be prepared in a liquid ink that is simply printed to produce a film of the material.

The components used to make the perovskite can be changed to give the materials different colours and structural properties, for example, making the films emit different colours or collect sunlight more efficiently.

You only need a very thin film of this perovskite material – around one thousand times thinner than a human hair – to achieve similar efficiencies to the silicon wafers currently used, opening up the possibility of incorporating them into windows or flexible, ultra-lightweight smartphone screens.

“This is the new class of semiconductors that could actually revolutionise all these technologies,” said Sascha Feldmann, a PhD student at Cambridge’s Cavendish Laboratory.

“These materials show very efficient emission when you excite them with energy sources like light or apply a voltage to run an LED.

“This is really useful but it remained unclear why these materials that we process in our labs so much more crudely than these clean-room, high-purity silicon wafers, are performing so well.”

Scientists had assumed that, like with silicon materials, the more ordered they could make the materials, the more efficient they would be. But Feldmann and his co-lead author Stuart MacPherson were surprised to find the opposite to be true. 

“The discovery was a big surprise really,” said Deschler, who is now leading an Emmy-Noether research group at TU Munich. “We do a lot of spectroscopy to explore the working mechanisms of our materials, and were wondering why these really quite chemically messy films were performing so exceptionally well.”

“It was fascinating to see how much light we could get from these materials in a scenario where we’d expect them to be quite dark,” said MacPherson, a PhD student in the Cavendish Laboratory. “Perhaps we shouldn’t be surprised considering that perovskites have re-written the rule book on performance in the presence of defects and disorder.”

The researchers discovered that their rough, multi-component alloyed preparations were actually improving the efficiency of the materials by creating lots of areas with different compositions that could trap the energised charge carriers, either from sunlight in a solar cell, or an electrical current in an LED.

“It is actually because of this crude processing and subsequent de-mixing of the chemical components that you create these valleys and mountains in energy that charges can funnel down and concentrate in,” said Feldmann. “This makes them easier to extract for your solar cell, and it’s more efficient to produce light from these hotspots in an LED.”

Their findings could have a huge impact on the manufacturing success of these materials.

“Companies looking to make bigger fabrication lines for perovskites have been trying to solve the problem of how to make the films more homogenous, but now we can show them that actually a simple inkjet printing process could do a better job,” said Feldmann. “The beauty of the study really lies in the counterintuitive discovery that easy to make does not mean the material will be worse, but can actually be better.”

“It is now an exciting challenge to find fabrication conditions which create the optimum disorder in the materials to achieve maximum efficiency, while still retaining the structural properties needed for specific applications,” said Deschler.

“If we can learn to control the disorder even more precisely, we could expect further LED or solar cell performance improvements – and even push well beyond silicon with tailored tandem solar cells comprising two different colour perovskite layers that together can harvest even more power from the sun than one layer alone,” said Dr Sam Stranks, University Lecturer in Energy at the Cambridge Department of Chemical Engineering and Biotechnology and the Cavendish Laboratory.

Another limitation of perovskite materials is their sensitivity to moisture, so the groups are also investigating ways to improve their stability.

“There’s still work to do to make them last on rooftops the way silicon can – but I’m optimistic,” said Stranks.

Reference:
Sascha Feldmann et al. ‘
Photodoping through local charge carrier accumulation in alloyed hybrid perovskites for highly efficient luminescence.’ Nature Photonics (2019). DOI: 10.1038/s41566-019-0546-8

A bold response to the world’s greatest challenge
The University of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the University’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

Discovery means simpler and cheaper manufacturing methods are actually beneficial for the material’s use in next-generation solar cells or LED lighting.

The beauty of the study really lies in the counterintuitive discovery that easy to make does not mean the material will be worse, but can actually be better
Sascha Feldmann
Artist's impression of perovskite structures

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Yes

Hitachi and Cambridge renew 30 year research partnership

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The relationship will build on the 30-year partnership established with the University through the Cavendish Laboratory, home of the University’s Department of Physics, and will pursue deep science leading to the development of cutting-edge technology to develop a practical quantum computer.

The collaborative activity between HCL and the Cavendish Laboratory, which began in 1989 to create new concept advanced electronic and optoelectronic devices, has resulted in technology milestones such as the demonstration of the world’s first single-electron memory device, the first single-electron logic device, measurement of the Spin-Hall effect and one of the first silicon qubit devices, the Spin-injection Hall effect, and a prototype Spin-Hall effect transistor. A part of such works led to the development of major activity on quantum computation.

Today, the development of an ecosystem in this area covering activities across the University, as well as companies in the Cambridge cluster – the largest technology cluster in Europe – is a central priority for HCL.

Under the terms of the new agreement, HCL will carry out next-generation computing research with the Cavendish Laboratory in addition to ongoing fundamental research, and the partnership will continue at the Ray Dolby Centre, the new home of the Cavendish Laboratory, due to open in 2022.

The new home of the Cavendish will operate as a National Facility for the UK physics community and its industrial partners. Hitachi and the University have agreed that the Ray Dolby Centre will be the ideal home for HCL.

University researchers pursue world-leading research ranging from new devices to algorithms for next-generation computers such as quantum computers, which are exponentially faster than classical computers, revolutionising fields as diverse as cryptography and drug discovery.

Professor Andy Parker, Head of the Cavendish Laboratory said: “HCL and the Cavendish have operated as partners for three decades, producing world-leading results and enabling great new products to be developed. We are proud that Hitachi have chosen to continue our partnership in our new facility and look forward to many more years of outstanding results.”

“Working with the Cavendish Laboratory and research partners, we have made significant advances in Si-based quantum devices over the last few years,” said Dr Masakatsu Mori, CTO of Hitachi Europe Ltd. “The next step towards a practical quantum computer based on this technology will be to extend the research beyond the device to computer science, to include architecture and systems consideration. We are excited to be moving forward together with the University of Cambridge in this new endeavour.”

“HCL and the Department of Physics at the University of Cambridge have built a strong and successful collaboration over the past 30 years,” said Professor David Cardwell, Pro-Vice-Chancellor for Strategy and Planning, who signed the MoU on behalf of the University. “This new phase of the collaboration creates an important opportunity for HCL to expand and extend its network throughout the University and its many collaborators that support our joint vision for the future. The Cavendish III development aims to be the best research centre for physics in the world and this ambitious project represents an excellent opportunity for HCL to continue its substantial collaboration with the University of Cambridge.”

“We are proud of the relationship that has grown over the last 30 years with the University of Cambridge,” said Dr Norihiro Suzuki, Vice President and Executive Officer, and CTO of Hitachi. “By building on this valuable partnership, the best minds in academia and industry will become part of an innovation ecosystem ensuring that the fruits of the research have true value and contribute to a better society.”

The Ray Dolby Centre is named in recognition of an £85 million gift from the estate of sound pioneer Ray Dolby – the largest philanthropic donation ever made to UK science.

In addition to the Dolby gift, the new Cavendish Laboratory is being made possible by £75 million of funding from the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI). The project, which is expected to be completed in 2022, will help strengthen the University’s position as a leading site for physics research and will provide a top-class facility for the nation, with much of the research equipment made available to other institutions.

The University of Cambridge and Hitachi Ltd have signed a new agreement to continue and grow their long-standing relationship through the Hitachi Cambridge Laboratory (HCL), part of the European R&D Centre of Hitachi Europe Ltd.

The Cavendish III development aims to be the best research centre for physics in the world and this ambitious project represents an excellent opportunity for HCL to continue its substantial collaboration with the University of Cambridge
David Cardwell

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Cambridge Zero

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Cambridge Zero
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CAMBRIDGE ZERO

Florian Gaertner/Photothek via Getty Images

Florian Gaertner/Photothek via Getty Images

If we are to avert a climate disaster, we must sharply reduce our emissions, starting today.

Cambridge Zero, the University's ambitious new climate initiative, will generate ideas and innovations to help shape a sustainable future - and equip future generations of leaders with the skills to navigate the global challenges of the coming decades.

Cambridge is the brand-new holder of a dubious record. On 25 July 2019, the temperature at the University’s Botanic Garden hit a new all-time record high for the UK: 38.7°C.

Few expect this record to hold for long. As temperatures rise globally, extreme weather events – floods, storms, droughts and heatwaves – are becoming the new normal. The Intergovernmental Panel on Climate Change (IPCC) has clearly articulated that, if this continues, we risk venturing into a world of climate-driven food shortages, water stress, refugees, species loss and catastrophic shocks such as the collapse of the vast polar ice sheets.

Scientists have been warning for decades that man-made climate change is happening. But with a few exceptions, we have done little about it. In the past 18 months, however, there has been a noticeable shift.

“The basic science hasn’t changed: what is starting to change is public opinion,” says Dr Emily Shuckburgh (pictured), one of the UK’s leading climate scientists. “As the impacts of climate change are starting to be felt around the world, it’s finally cutting through that we need to do something and we need to do it now. If we are to avert a climate disaster, we must sharply reduce our emissions, starting today.”

Shuckburgh recently joined the University from the British Antarctic Survey to lead an ambitious new programme: Cambridge Zero. The programme will harness the full breadth of the University’s research capabilities across the sciences, engineering, humanities and social sciences to respond to climate change and support the transition to a resilient, sustainable future.

Cambridge Zero is not just about developing greener fuels, technologies and materials. It’s about addressing every aspect of a zero carbon future: the impact it will have on our lives, our work, our society and our economy, and ensuring decisions are based on the best available knowledge.

By developing a bold programme of education, research, demonstration projects and knowledge exchange focused on supporting a zero carbon world, the initiative’s ambition is to generate and disseminate the ideas and innovations that will shape our future – and to equip a future generation of leaders with the skills to navigate the global challenges of the coming decades.

Its launch comes a few months after the UK became the first major world economy to legislate for net zero emissions. Eliminating greenhouse gas emissions by 2050 will mean a fundamental change over the coming decades in all aspects of our economy, including how we generate energy, and how we build decarbonisation into policy and investment.

Emily Shuckburgh

CLEAN ENERGY

“The challenge is how to develop the technologies for the energy transition at the scale, and on the timescales, that we need,” says Professor Sir Richard Friend, Director of Energy Transitions@Cambridge, which brings together over 250 Cambridge researchers working on areas such as bioenergy, batteries, photovoltaics, carbon capture, propulsion and power, and cities and transport.

Friend is one of the UK’s leaders in the development of next-generation solar cells and super-efficient LEDs, and has founded several spin-out companies based on his research. Since the 1980s, his group at the Cavendish Laboratory has been developing materials for low-cost solar cells that could surpass silicon’s efficiency in converting sunlight into energy.

Through initiatives such as the Henry Royce Institute, the UK’s national institute for materials science research and innovation, Cambridge researchers are also developing next-generation materials for energy storage and use.

“Cambridge is already one of the UK’s leading universities in battery science and a major contributor to the Faraday Institution’s battery programme for electric vehicles,” says Professor Manish Chhowalla, the Cambridge Royce Champion. “The Royce facilities help us supplement the chemistry and physics research we’re already doing with engineering approaches that will help bring our research to market faster.”

Friend adds that working in collaboration with industry is the only way to enable the energy transition. Although Cambridge has the research and knowledge base to identify new solutions, it does not have the capabilities to produce those solutions on an industrial scale: “It’s important to understand what industry actually wants, rather than what we presume it wants.”

Solar panels

CLIMATE CHANGE POLICY

Even if a scientist or engineer develops a new technology that solves a problem associated with the energy transition, how do policy changes make the most of innovation?

This question lies at the heart of the work of Laura Diaz Anadon, Professor of Climate Change Policy in Cambridge’s Centre for Environment, Energy and Natural Resource Governance, and a lead author on the IPCC’s sixth Assessment Report.

“When I first moved into policy and economics work after my PhD in chemical engineering, I was focused on solutions as if they were things that people could and would start using tomorrow. I realised quickly that I wasn’t thinking about cost-effectiveness and the role of policy, regulation, business models, political support and their impacts. That was really eye-opening for me,” says Diaz Anadon.

“Climate change policy is particularly challenging as it cuts across so many sectors and demands engagement with many different stakeholders,” says Dr David Reiner, from the Energy Policy Research Group at Cambridge Judge Business School, and one of the co-editors of the recent book In Search of Good Energy Policy with Professor Michael Pollitt. “Good policy isn’t just about getting the numbers right, because even the numbers are controversial,” says Reiner. “Different groups have different priorities, so how do we determine which numbers to put stock in and which things are actually important?”

Shuckburgh is echoing this broad approach in Cambridge Zero. “This is a once-in-a-generation opportunity for us to make an impact, which is why it’s vital we bring in multiple perspectives to ensure that we’re translating scientific knowledge into innovations that are rapidly deployed in the real world – and robust, evidence-based policy that works for everyone,” she says.

“It’s great to see climate change finally breaking through as a priority with the public,” says Pollitt. “But the challenge has always been when you start asking about specifics. Lifestyle changes are cheap, but they’re intrusive. And if you aren’t willing to become a vegetarian, turn the heating down or stop flying, then you’re going to need serious decarbonisation policies to reach where we need to get to.”

A major energy policy – such as decarbonising the electricity grid or banning petrol cars – generally requires a decade of planning, and another two decades to implement. It also requires public engagement, says Pollitt: “If the public feel they haven’t been consulted on a new policy, they’re less likely to support it, and they need to see that these policies have benefits that minimise the negative effects. A carbon neutral economy isn’t unachievable, but there are massive challenges associated with it, and we have to face those challenges with eyes wide open.”

Protesters

SUSTAINABLE FINANCE

Beyond policy, the transition to a zero carbon future will also require unprecedented levels of government, private and institutional investment in green and low carbon technologies, services and infrastructure. And financial institutions themselves will need to move to a sustainable finance model, pricing environmental and social risks correctly.

These are areas that interest Dr Nina Seega at the Cambridge Institute for Sustainability Leadership, which bridges the worlds of business, policymaking and finance. “Since the attention called to the issue by the G20 Green Finance Study Group in 2016, we’ve seen lots of discussion about sustainable finance in the financial world but more action is needed to thread sustainable finance into the day-to-day work of financial firms.

“When we have conversations with financial firms, what we get is a conversation about the costs and risks of transition to a zero carbon future. However, it is refreshing to see the focus turning to opportunities of sustainable finance and the cost of not transitioning. Simply put, it is more expensive to do nothing.”

This point is illustrated by the recent Green Finance Strategy, in which the UK government predicts that the population health impacts of not delivering on emissions reductions could be around £1.7 billion per year by 2020 and £5.3 billion per year by 2030.

“Unfortunately, there is still a persistent perception that sustainable investment means sacrificing profitability, but that’s not the case,” Seega says. “A 2015 review of 2,200 studies found that sustainability has at least a non-negative, and in most cases a positive, relationship to profitability. Prioritising sustainability does not mean sacrificing profitability.”

Wind turbines

REASONS TO BE OPTIMISTIC

One of the major successes of global efforts in energy and climate policy has been advances in developing low carbon solutions, which is beginning to pay off. Just since 2010, the average cost of producing electricity globally from solar PV panels has decreased by 77%, and from wind turbines by 34%, and the cost of storing energy in lithium-ion batteries has decreased by 89%, in turn making electric vehicles less expensive.

“Nobody really predicted that costs would come down so fast,” says Diaz Anadon, who analysed these figures as part of INNOPATHS, a project funded by the European Union. “Governments around the world have been key drivers of these cost reductions, both through investments in R&D, and policies to incentivise their commercialisation, such as feed-in tariffs, carbon prices and other regulations.”

Even so, considering the scale and urgency of the climate change problem, it’s easy to become overwhelmed. But Shuckburgh is optimistic that a zero carbon world is achievable.

“Cambridge has the power to bring together industry, finance, policymakers, NGOs and other partners to jointly propose ambitious solutions. But we all need to work together to make this happen,” she says.

“The human race has achieved incredible things: lifted billions of people out of poverty, cured diseases, travelled to the moon. The biggest challenge now is how we preserve our only home for future generations, and we need to respond to the challenge with all of our efforts. We cannot fail.” 

Cost of renewable energy

SNAPSHOT: THE INVESTMENT RESEARCHER

Understanding what society must do to decarbonise is the most complex and important puzzle we have ever had to solve, says Dr Ellen Quigley, a researcher at Cambridge Judge Business School and the Centre for the Study of Existential Risk.

“We need electrification of our energy systems, decarbonisation of supply chains, new technologies that will help us cut emissions by at least half by 2030 – or sooner – and all of this needs a financial ecosystem that is up to the task. Plus, we are the last generation who can do something about catastrophic climate change.”

Appointed earlier this year as the Advisor to the Chief Financial Officer of the University, Quigley is establishing a research programme to understand how shifting the focus of investment – at institutional, national and global levels – can achieve system-wide changes that “will help us move rapidly and justly” towards decarbonisation.

“I’m one of many who are worrying about whether the financial system is fit for purpose in an era of climate crisis. My research is looking at everything an institution like the University can do in terms of responsible investment – from encouraging financing of decarbonisation spin-outs, to adopting soil management techniques to sequester carbon, to supporting government policies like carbon pricing.

“Everything we do here in Cambridge could be a useful template for other institutions. We are picking the things that are most effective and moving as quickly as possible in this very brief period we have to make the difference we need to make.”

Dr Ellen Quigley
Summary: 

If we are to avert a climate disaster, we must sharply reduce our emissions, starting today. Cambridge Zero, the University's ambitious new climate initiative, will generate ideas and innovations to help shape a sustainable future - and equip future generations of leaders with the skills to navigate the global challenges of the coming decades. 

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UK researchers awarded £30m for global science project to better understand matter and antimatter

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The University of Cambridge will provide essential contributions to the DUNE experiment, a global science project that brings the scientific community together to work on trying to answer some of the biggest questions in physics.

DUNE (the Deep Underground Neutrino Experiment) is hosted by the United States Department of Energy’s Fermilab, and will be designed and operated by a collaboration of over 1,000 physicists from 32 countries.

The project aims to advance our understanding of the origin and structure of the universe. It will study the behaviour of particles called neutrinos and their antimatter counterparts, antineutrinos. This could provide insight as to why we live in a matter-dominated universe while anti-matter has largely disappeared.

“DUNE has the unique potential to answer fundamental questions that overlap particle physics, astrophysics, and cosmology,” said Professor Stefan Söldner-Rembold of the University of Manchester, who leads the international DUNE collaboration as one of its spokespeople.

The investment, from UK Research and Innovation’s Science and Technology Facilities Council (STFC), is a four-year construction grant to 13 educational institutions, and to STFC’s Rutherford Appleton and Daresbury Laboratories. This grant, of £30m, represents the first of two stages to support the DUNE construction project in the UK which will run until 2026 and represent a total investment of £45m.

Various elements of the experiment are under construction across the world, with the UK taking a major role in contributing essential expertise and components to the experiment and facility. UK scientists and engineers will design and produce the principle detector components at the core of the DUNE detector, which will comprise four large tanks each containing 17,000 kg of liquid argon.

The UK groups are also developing a high-speed data acquisition system to record the signals from the detector, together with the sophisticated software needed to interpret the data and provide the answers to the scientific questions.

“DUNE could help to change the way we understand the universe,” said Dr Melissa Uchida, who leads the neutrino group at Cambridge’s Cavendish Laboratory. “This announcement has allowed the UK to take a leading role in many aspects of the experiment, making the UK the biggest DUNE contributor outside the USA. Our group will deliver hardware and software, as well as calibration and analysis effort for DUNE and we are ready and excited to meet the challenges ahead.”

DUNE will also watch for supernova neutrinos produced when a star explodes, which will allow the scientists to observe the formation of neutron stars and black holes and will investigate whether protons live forever or eventually decay, bringing us closer to fulfilling Einstein’s dream of a grand unified theory.

The other UK universities involved in the project are Birmingham, Bristol, Edinburgh, Imperial College London, Lancaster, Liverpool, Manchester, Oxford, Sheffield, Sussex, UCL and Warwick.

Cambridge researchers will receive funding as part of a £30m investment in the DUNE experiment, which has the potential to lead to profound changes in our understanding of the universe.

Inside ProtoDUNE at CERN

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Women in STEM: Angela Harper

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I would like to see the future renewable energy frontiers led by women. I hope I will be one of these women, along with the many other female scientists who are paving the way towards a greener future. It is hard to ignore the global need for better renewable energy sources and storage as soon as possible, and I hope my research will lead to better energy storage alternatives sooner rather than later.

Determination will take you far in life. Any time someone tells you that you aren't good enough to pursue a career in science, or perhaps you should "do something more suited for your skills" take that as a challenge to prove that person wrong. My advice to other women is to be confident that you ARE smart enough, you ARE brilliant, and don't let anyone tell you otherwise.

It never seemed odd to me that a woman would want to pursue physics. I grew up in Clifton Park, New York, and went to a large public high school with almost 1000 students per year. I was fortunate enough to have female science teachers throughout high school, and it was partly their influence that led me to major in physics at university.

At university, I helped to set up a Women in STEM programme. I attended Wake Forest University, a liberal arts college in North Carolina. With this programme, we created an after-school project with a local middle school called ‘Girls in STEM’ which helped girls age 12-15 start thinking about STEM careers. 

Choosing my Master's project was one of the hardest moments of my research career. I finally had the chance to create my own project, and I found this incredibly challenging but also so rewarding to know that all the work I do on this project is wholly my own. My research sets out to address our global need for storing renewable energy. I currently design lithium-ion battery materials using computational techniques, with the aim of developing a battery with long life and high capacity. This would mean that we are able to use solar, wind, and renewable energy, and store this energy effectively in Li-ion batteries.

I am a theoretical physicist, so each day I come in and work on the computer. My work involves creating models of new materials, calculating energies of different battery material structures, and developing code to better understand these materials. I work in the Theory of Condensed Matter group, located in West Cambridge at the Cavendish site. In chemistry, we learn about different orbitals, energy states, and phases of materials. But actually visualising and creating a material with these chemical properties was something new for me. The first day I was able to actually visualise, on my computer screen, the orbitals in a material I had computationally identified was a fantastic moment. 

In Cambridge, every academic I talk to at all levels is concerned about improving renewable energy sources. For this reason, I have found Cambridge an incredible place to conduct research on energy materials. Furthermore, the international nature of Cambridge has helped me build collaborations in countries I would not have had access to from the United States.  

It is impossible to walk into a pub, coffee shop, or grocery store without hearing incredibly academic conversations, and I have found that academically driven environment to be extremely rewarding.

 

A bold response to the world’s greatest challenge
The University of Cambridge is building on its existing research and launching an ambitious new environment and climate change initiative. Cambridge Zero is not just about developing greener technologies. It will harness the full power of the University’s research and policy expertise, developing solutions that work for our lives, our society and our biosphere.

 

Angela Harper is a PhD candidate at the Cavendish Laboratory, a member of Churchill College, and a Gates Cambridge Scholar. Here, she tells us about her work in renewable energy, setting up a Girls in STEM programme while she was an undergraduate in North Carolina, and the importance of role models when pursuing a career in STEM. 

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The 'P' word

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The 'P' word
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The 'P' word


It's time for blue-sky thinking plus practical measures in the battle to reduce plastic waste.

In Tokyo, a householder consults her 60-page ‘Garbage Separation and Disposal’ system to check whether it's a recycle day for plastic bottles or for all other plastic packaging.

In a coastal village in Kenya, an order has been received for 2,000 bricks made from waste plastic and earth.

On a chemistry bench in Cambridge, bubbles of hydrogen form and rise around a thumbnail-sized square of plastic cut from a water bottle.

All around the world there are instances where we are getting things right with plastic – recycling, recovering, re-using – and instances where we are getting things very wrong.

Our awareness of just how wrong is riding the crest of a plastic-polluted wave: every year, more than 8 million tonnes of plastic waste ends up in the world’s oceans. Environmental agencies have predicted that if these trends continue, our oceans will contain more plastic than fish by 2050.

Plastic has become a malevolent symbol of our wasteful society. But it's also one of the most successful materials ever invented: it’s cheap, durable, flexible, waterproof, versatile and lightweight. It’s fundamental to almost every aspect of our lives and it's a resource that we are wasting, says Professor Erwin Reisner.

“As a chemist I look at plastic and I see an extremely useful material that is rich in chemicals and energy – a material that shouldn’t end up in landfills and pollute the environment. Plastic is an example of how we must find ways to use resources without irreversibly changing the planet for future generations.”

Reisner leads Cambridge University's new Cambridge Creative Circular Plastics Centre (CirPlas). Funded by UK Research and Innovation, it aims to eliminate plastic waste by combining blue-sky thinking with practical measures, connecting expertise across the disciplines, and collaborating with industry and local government.

In doing so, their research reaches from the Tokyo householder to the Kenyan brickmaker to the Cambridge chemist, and yet further still.

Plastic bottle in the ocean

How do we keep track of plastic?

Ask anyone what they know about plastic and they might tell you about the need to ban single-use materials, or that it’s essential for healthcare, or that it’s lighter and more fuel efficient than packaging alternatives.

“What no-one will tell you is how any of this relates to how much and what type of plastic we use, how long those products are in service, and what happens to them afterwards. The fact is – no-one knows,” says Dr Andre Serrenho.

It seems a simple enough set of questions but the data is complex and held by many different bodies. And so, as part of CirPlas, he and Dr Jonathan Cullen in the Department of Engineering are creating a map of the flow of plastic in the UK economy by amassing all of this data in one place.

Meanwhile, engineer Dr Ronan Daly is exploring digitally enabled solutions to label and track plastic, and zoologist Dr David Aldridge is using sensing technologies to measure how much microplastic is entering the food chain.

“All of these studies will take us closer to answering something we’ve never been able to answer before,” adds Serrenho. “Plastic helps us live safer, more convenient lives but how much is enough plastic and how much is too much?”

Zero waste from industry

One area where plastic has transformed modern-day living is in food safety. Of the 5 million tonnes of plastic used each year by the UK, 37% is used for packaging, of which almost three-quarters is for soft drinks. The challenges presented by waste from this packaging cannot be ignored, least of all by the industries that depend on it.

“What’s needed now is collective and informed action from individuals, government and business to shift us back in the right direction,” says Beverley Cornaby.

Last year, she and colleagues at the Cambridge Institute for Sustainability Leadership worked with 10 of the UK’s largest bottled drinks companies to understand what this collective action might look like. The result was an ambitious roadmap for zero plastic packaging waste from the industry being sent to landfill or escaping into the natural landscape by 2030.

“One of the areas we identified was around design. Businesses can sometimes move faster than government policy and so making changes to their own products can provide quicker fixes,” she adds.

“We’ve worked with companies to understand how to reconsider their approach to using plastic packaging. We’re now looking at alternative packaging choices and what the relative impact might be on carbon emissions, and water and land use.”

Manufacture of plastic drinking bottles

Plastic rematerialised

It seems that our need for plastic is here to stay, and so Cambridge researchers are exploring how we re-use it – as well as developing alternatives to take its place.

Taylor Uekert, working with Dr Erwin Reisner in the Department of Chemistry, has developed a technology called photoreforming that turns plastic waste into hydrogen fuel, using only water, a photocatalyst and sunlight. The technology is still very new but already the researchers have produced enough hydrogen from polyester fibres to power a phone for 40 seconds.

Dr Aazara Oumayyah Pankan is also exploring electricity generation from waste plastic – this time using biology. She’s testing microorganisms from environments like toxic waste dumps for their ability to decompose plastic. Working with Dr Adrian Fisher in the Department of Chemical Engineering and Biotechnology, she aims for these ‘plastic composters’ to provide off-grid power for rural communities.

In Kenya, a coastal community has started converting waste plastic into bricks, using a method developed by a student-led team from Cambridge’s Department of Engineering and prototyped by the Kenyan community. They have just received an order for 2,000 bricks for a local school.

Physicist Professor Jeremy Baumberg is using plastic waste as the raw materials for low-cost 3D printers. His team’s approach is to design printable scientific instruments like microscopes for resource-poor countries to turn low-value waste into high-value locally manufactured components.

Meanwhile, biochemist Professor Paul Dupree and materials scientist Professor James Elliott have set out to design a completely new class of materials based on modified plant fibres that have some of the good properties of plastic and yet are easy to recycle or decompose naturally.

Case study: The solution catalyser

Bringing the right people together to solve a major global environmental problem like waste is essential.

With this in mind, Dr Curie Park from the Institute for Manufacturing took her emergent circular economy process for creating the right mix of people to Thailand, funded by a Global Challenges Research Fund Impact Acceleration Award.

“Thailand uses a staggering amount of single-use plastics every day, but its waste management system lags far behind its economic advances,” she explains. “We saw first-hand the marine waste at a coastal village, where plastic debris floats from the rivers and is washed up as current changes seasonally.

“Everyone recognised the problem, which seemed too big for any one individual to tackle. But there had been regular beach cleaning activities and some of this collected plastic could be turned into viable products locally.

“We brought together a construction company, an environmental NGO, university students, a local windsurfing world champion turned beach cleaning heroine, municipal officers, local primary schools and start-ups, and applied our innovation process.

“Giving everyone a chance to share their views, providing stimuli and sharing what’s happening in other communities ignited a creative momentum to come up with novel solutions. We ended up with 56 ideas for using the waste as a raw material – paddleboards, compost bins, roof tiles – seven of which are in the commercialisation pipeline by the construction company and the local start-ups.”

Curie Park and the local beach cleaning group in Thailand

Curie Park and the local beach cleaning group in Thailand

Curie Park and the local beach cleaning group in Thailand

Words to live by

Put simply, plastic is incredibly useful – and it's being wasted.

“There’s a word in Japanese that conveys a feeling of regret when something useful is wasted. It’s mottainai,” says anthropologist Dr Brigitte Steger, from the Faculty of Asian and Middle Eastern Studies. As part of CirPlas, Steger and her team look at cultural attitudes to plastic and waste globally. Her own research focuses on Japan.

“The Japanese are very good citizens in terms of sorting and recycling but they also use a huge amount of plastic – and they don’t regard single-use plastic with mottainai,” she says.

In Tokyo, the 'Garbage Separation and Disposal' advice extends to 60 pages. “One woman being rehoused after the Fukushima Daiichi nuclear disaster told me she would only move to an area where she was familiar with the complexities of the recycling system,” says Steger.

Advice to householders in Tokyo on waste separation for recycling

Advice to householders in Tokyo on waste separation for recycling

“We need to understand what practical and moral needs plastic fulfils to know what can be done to shift behaviour towards living more sustainably. Moreover, policymakers define solutions in response to how problems are defined. We need to clarify these.”

What if we could shift our 'take, make, throw-away' plastic world towards 'recycle, recover, re-use'?

“Today’s cradle-to- grave economy sees around 80% of plastic landfilled, incinerated or lost into the natural environment,” says economist Dr Khaled Soufani. “It is argued by some that we are using resources 50% faster than can be replenished. It has also been said that by 2030 we will require the natural resources sources of two Earths, and by 2050, three.”

Soufani leads the Circular Economy Centre in Cambridge Judge Business School. He and Steger are contributing to CirPlas by asking how individuals, communities, companies and public bodies approach their use and recycling of plastic.

“What we need,” says Soufani, “is a circular economy with re-use of products and recycling of embedded materials into new products for as long as possible.”

Film: Khaled Soufani talks about moving towards a more sustainable future via the circular economy

Circularity by design

Cambridgeshire-based packaging company Charpak believes it is the first in the UK to adopt a ‘localised circular economy’ in which local plastic waste is collected, re-processed and re-manufactured into new packaging.

The company has been chosen by Soufani’s team as a case study to look at the viability of a circular business model. The translation of the circular economy in business models that eliminate plastic is relatively unexplored and so there's little guidance for practitioners who would like to adopt such a model.  The researchers are addressing this gap by mapping how Charpak has approached the circular economy and by estimating the impact of their efforts.

Worker at Charpak

Worker at Charpak

Worker at Charpak

“Before any company will look at embedding circularity, they are going to ask a very simple question: how will it impact on me financially? Communities, companies and governing bodies need to see practical business cases and models in action,” adds Soufani.

“Minimising plastic leaking into our environment is a responsibility we take very seriously, so we must ensure plastic becomes a resource and not waste,” says Charpak Managing Director Paul Smith. “Why transport essential plastics resources nationwide, or overseas, and risk ocean plastics when the plastic resource is required for manufacture and re-manufacture within the UK? We want to be part of the solution.”

Soufani agrees, adding: “We need to shift from a culture of mass consumption and waste towards renewability, dematerialisation and reduced resource loss.

Our need to reduce, remake and recycle is a continuous journey towards circularity that will define our relationship with the planet forever.
Khaled Soufani

Image credits:
Sky girl:
Karina Tess
Water bottle in the ocean, Indonesia:
Brian Yurasits
Plastic in a field:
Masha Kotliarenko
Manufacture of plastic drinking bottles:
Jonathan Chng

Summary: 

How do we shift our 'take, make, throw-away' plastic world towards 'recycle, recover, re-use'? It's time for blue-sky thinking plus practical measures in the battle to reduce plastic waste. 

Image: 
Section: 
News type: 

Watching magnetic nano ‘tornadoes’ in 3D

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The team, from the Universities of Cambridge and Glasgow in the UK and ETH Zurich and the Paul Scherrer Institute in Switzerland, used their technique to observe how the magnetisation behaves, the first time this has been done in three dimensions. The technique, called time-resolved magnetic laminography, could be used to understand and control the behaviour of new types of magnets for next-generation data storage and processing. The results are reported in the journal Nature Nanotechnology.

Magnets are widely used in applications from data storage to energy production and sensors. In order to understand why magnets behave the way they do, it is important to understand the structure of their magnetisation, and how that structure reacts to changing currents or magnetic fields.

“Until now, it hasn’t been possible to actually measure how magnets respond to changing magnetic fields in three dimensions,” said Dr Claire Donnelly from Cambridge’s Cavendish Laboratory, and the study’s first author. “We’ve only really been able to observe these behaviours in thin films, which are essentially two dimensional, and which therefore don’t give us a complete picture.”

Moving from two dimensions to three is highly complex, however. Modelling and visualising magnetic behaviour is relatively straightforward in two dimensions, but in three dimensions, the magnetisation can point in any direction and form patterns, which is what makes magnets so powerful.

“Not only is it important to know what patterns and structures this magnetisation forms, but it’s essential to understand how it reacts to external stimuli,” said Donnelly. “These responses are interesting from a fundamental point of view, but they are crucial when it comes to magnetic devices used in technology and applications.”

One of the main challenges in investigating these responses is tied to the very reason magnetic materials are so relevant for so many applications: changes in the magnetisation typically are extremely small, and happen extremely fast. Magnetic configurations – so-called domain structures – exhibit features on the order of tens to hundreds of nanometres, thousands of times smaller than the width of a human hair, and typically react to magnetic fields and currents in billionths of a second.

Now, Donnelly and her collaborators from the Paul Scherrer Institute, the University of Glasgow and ETH Zurich have developed a technique to look inside a magnet, visualise its nanostructure, and how it responds to a changing magnetic field in three dimensions, and at the size and timescales required.

The technique they developed, time-resolved magnetic laminography, uses ultra-bright X-rays from a synchrotron source to probe the magnetic state from different directions at the nanoscale, and how it changes in response to a quickly alternating magnetic field. The resulting seven-dimensional dataset (three dimensions for the position, three for the direction and one for the time) is then obtained using a specially developed reconstruction algorithm, providing a map of the magnetisation dynamics with 70 picosecond temporal resolution, and 50 nanometre spatial resolution.

What the researchers saw with their technique was like a nanoscale storm: patterns of waves and tornadoes moving side to side as the magnetic field changed. The movement of these tornadoes, or vortices, had previously only been observed in two dimensions.

The researchers tested their technique using conventional magnets, but they say it could also be useful in the development of new types of magnets which exhibit new types of magnetism. These new magnets, such as 3D-printed nanomagnets, could be useful for new types of high-density, high-efficiency data storage and processing.

“We can now investigate the dynamics of new types of systems that could open up new applications we haven’t even thought of,” said Donnelly. “This new tool will help us to understand, and control, their behaviour.”

The research was funded in part by the Leverhulme Trust, the Isaac Newton Trust and the European Union.

Reference:
Claire Donnelly et al. ‘Time-resolved imaging of three-dimensional nanoscale magnetization dynamics.’ Nature Nanotechnology (2020). DOI: 10.1038/s41565-020-0649-x

Scientists have developed a three-dimensional imaging technique to observe complex behaviours in magnets, including fast-moving waves and ‘tornadoes’ thousands of times thinner than a human hair.

We can now investigate the dynamics of new types of systems that could open up new applications we haven’t even thought of
Claire Donnelly
Reconstruction of 3D magnetic structure

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Yes

Identification of viruses and bacteria could be sped up through computational methods

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Close-up of virus molecule

The researchers, led by the University of Edinburgh, with colleagues from Cambridge, London, Slovenia and China, used a combination of theoretical and experimental methods to develop a strategy to detect the DNA of infectious diseases. The results are reported in the Proceedings of the National Academy of Sciences.

The current coronavirus pandemic highlights the need for fast and accurate detection of infectious diseases. Importantly, viral infections like coronavirus and bacterial infections like those associated with antimicrobial resistance (AMR) need to be distinguished. This is usually done by using a complementary sequence that binds selectively to the genome of interest. Normally, this is done by targeting a single, long DNA sequence that is unique to the pathogen.

However, the researchers believe that much higher selectivities can be achieved by simultaneously targeting many shorter sequences that occur with a higher frequency in the pathogen of interest than in the DNA of other organisms that may be present in the patient samples.

"This approach exploits a phenomenon called ‘multivalency’, and the extensive numerical calculations, based on real bacterial and viral DNA sequences show that this approach should significantly outperform current approaches," said co-author Professor Erika Eiser from Cambridge’s Cavendish Laboratory. "Even though the individual shorter sequences bind more weakly to the target DNA than a single, longer sequences, the strength of the multivalent binding increases much faster than linearly with the number of short sequences."

In other words, instead of designing molecular probes that bind strongly to one place on the target DNA, researchers should, counterintuitively, design probes that bind weakly all over the target DNA. Making such relatively short probe sequences is, at present, a standard procedure and the sequences can be ordered online.

The experimental part of the project started with experiments in Cambridge, showing that the method can work in principle on a mixture of viral DNA and colloids coated with short complementary strands. Then the simulations took over to predict what combination of probe sequences would give the highest selectivity.

This part of the project has so far only been tested in computer models. The next step is to carry out experiments on real mixtures of viral and bacterial DNA.

"Experiments are needed to test how well this works in practice – but it is exciting work, given the urgent need for fast, reliable disease detection methods, especially those that can be applied in countries with a weak health infrastructure," said Professor Rosalind Allen from the University of Edinburgh, who led the research.

This work was performed before the COVID-19 pandemic. However, the current emergency illustrates the need for robust and highly selective methods to quickly identify specific viruses – particularly in ‘low-tech’ environments.

The research was funded in part by the Royal Society and the European Research Council.

Reference:
Tine Curk et al. ‘Computational design of probes to detect bacterial genomes by multivalent binding.’ PNAS (2020). DOI: 10.1073/pnas.1918274117

Adapted from a University of Edinburgh press release.

 

How you can support Cambridge's COVID-19 research effort

Donate to support COVID-19 research at Cambridge

 

A new multinational study has shown how the process of distinguishing viruses and bacteria could be accelerated through the use of computational methods.

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Yes

Cambridge researchers awarded European Research Council funding

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One hundred and eighty-five senior scientists from across Europe were awarded grants in today’s announcement, representing a total of €450 million in research funding. The UK has 34 grantees in this year’s funding round, the second-most of any ERC participating country.

ERC grants are awarded through open competition to projects headed by starting and established researchers, irrespective of their origins, who are working or moving to work in Europe. The sole criterion for selection is scientific excellence.

ERC Advanced Grants are designed to support excellent scientists in any field with a recognised track record of research achievements in the last ten years.

Professors Mete Atatüre and Jeremy Baumberg, both based at Cambridge’s Cavendish Laboratory, work on diverse ways to create new and strange interactions of light with matter that is built from tiny nano-sized building blocks.

Baumberg’s PICOFORCE project traps light down to the size of individual atoms which will allow him to invent new ways of tugging them, levitating them, and putting them together. Such work uncovers the mysteries of how molecules and metals interact, crucial for creating energy sustainably, storing it, and developing electronics that can switch with thousands of times less power need than currently.

"This funding recognises the huge need for fundamental science to advance our knowledge of the world – only the most imaginative and game-changing science gets such funding," said Baumberg.

Atatüre’s project, PEDESTAL, investigates diamond as a material platform for quantum networks. What gives gems their colour also turns out to be interesting candidates for quantum computing and communication technologies. By developing large-scale diamond-semiconductor hybrid quantum devices, the project aims to demonstrate high-rate and high-fidelity remote entanglement generation, a building block for a quantum internet.

"The impact of ERC funding on my group’s research had been incredible in the last 12 years, through Starting and Consolidator grants. I am very happy that with this new grant we as UK scientists can continue to play an important part in the vibrant research culture of Europe," said Atatüre.

Professor Judith Driscoll from Cambridge’s Department of Materials Science & Metallurgy was also awarded ERC funding for her work on nanostructured electronic materials. She is also spearheading joint work of her team, as well as those of Baumberg and Atatüre, on low-energy IT devices.

"My approach uses a different way of designing and creating oxide nano-scale film structures with different materials to both create new electronic device functions as well as much more reliable and uniform existing functions," she said. "Cambridge is a fantastic place that enables all our approaches to come together, driven by cohorts of inspirational young researchers in our UK-funded Centre for Doctoral Training in Nanoscience and Nanotechnology – the NanoDTC."

Professor John Robb from Cambridge’s Department of Archaeology was awarded an ERC grant for the ANCESTORS project on the politics of death in prehistoric Europe. The project takes the methods developed in the ‘After the Plague’ project and the taphonomy methods developed in the Scaloria Cave project and apply them to a major theoretical problem in European prehistory - the nature of community and the rise of inequality.

"This project is really exciting and I’ll be working with wonderful colleagues Dr Christiana ‘Freddi’ Scheib at the University of Tartu and Dr Mary Anne Tafuri at Sapienza University of Rome," said Robb. "The results will allow us to evaluate for the first time how inequality affected lives in prehistoric Europe and what role ancestors played in it."

Four researchers at the University of Cambridge have won advanced grants from the European Research Council (ERC), Europe’s premier research funding body.

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Yes

AI techniques used to improve battery health and safety

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The researchers, from Cambridge and Newcastle Universities, have designed a new way to monitor batteries by sending electrical pulses into them and measuring the response. The measurements are then processed by a machine learning algorithm to predict the battery’s health and useful lifespan. Their method is non-invasive and is a simple add-on to any existing battery system. The results are reported in the journal Nature Communications.

Predicting the state of health and the remaining useful lifespan of lithium-ion batteries is one of the big problems limiting widespread adoption of electric vehicles: it’s also a familiar annoyance to mobile phone users. Over time, battery performance degrades via a complex network of subtle chemical processes. Individually, each of these processes doesn’t have much of an effect on battery performance, but collectively they can severely shorten a battery’s performance and lifespan.

Current methods for predicting battery health are based on tracking the current and voltage during battery charging and discharging. This misses important features that indicate battery health. Tracking the many processes that are happening within the battery requires new ways of probing batteries in action, as well as new algorithms that can detect subtle signals as they are charged and discharged.

"Safety and reliability are the most important design criteria as we develop batteries that can pack a lot of energy in a small space," said Dr Alpha Lee from Cambridge’s Cavendish Laboratory, who co-led the research. "By improving the software that monitors charging and discharging, and using data-driven software to control the charging process, I believe we can power a big improvement in battery performance."

The researchers designed a way to monitor batteries by sending electrical pulses into it and measuring its response. A machine learning model is then used to discover specific features in the electrical response that are the tell-tale sign of battery aging. The researchers performed over 20,000 experimental measurements to train the model, the largest dataset of its kind. Importantly, the model learns how to distinguish important signals from irrelevant noise. Their method is non-invasive and is a simple add-on to any existing battery systems.

The researchers also showed that the machine learning model can be interpreted to give hints about the physical mechanism of degradation. The model can inform which electrical signals are most correlated with aging, which in turn allows them to design specific experiments to probe why and how batteries degrade.

"Machine learning complements and augments physical understanding," said co-first author Dr Yunwei Zhang, also from the Cavendish Laboratory. "The interpretable signals identified by our machine learning model are a starting point for future theoretical and experimental studies."

The researchers are now using their machine learning platform to understand degradation in different battery chemistries. They are also developing optimal battery charging protocols, powering by machine learning, to enable fast charging and minimise degradation.

This work was carried out with funding from the Faraday Institution. Dr Lee is also a Research Fellow at St Catharine’s College.

Reference:
Yunwei Zhang et al. ‘Identifying degradation patterns of lithium ion batteries from impedance spectroscopy using machine learning.’ Nature Communications (2020). DOI: 10.1038/s41467-020-15235-7

Researchers have designed a machine learning method that can predict battery health with 10x higher accuracy than current industry standard, which could aid in the development of safer and more reliable batteries for electric vehicles and consumer electronics.

Person holding white Android phone

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Yes

New app collects the sounds of COVID-19

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The COVID-19 Sounds App is now available as a web app for Chrome and Firefox browsers. Versions for Android and iOS will be available soon.

As COVID-19 is a respiratory condition, the sounds made by people with the condition – including voice, breathing and cough sounds – are very specific. A large, crowdsourced data set will be useful in developing machine learning algorithms that could be used for automatic detection of the condition.

"There’s still so much we don’t know about this virus and the illness it causes, and in a pandemic situation like the one we’re currently in, the more reliable information you can get, the better," said Professor Cecilia Mascolo from Cambridge’s Department of Computer Science and Technology, who led the development of the app.

"I am amazed at the speed that we managed to connect across the University to conceive this project, and how Cecilia's team of developers came together to respond to the urgency of the situation," said Professor Pietro Cicuta from Cambridge’s Cavendish Laboratory, a member of the team behind the app’s development. Professor Andres Floto, Professor of Respiratory Biology at the University, and Research Director of the Cambridge Centre for Lung Infection at Papworth Hospital, Cambridge, has also advised on the clinical aspects of the app.

The COVID-19 Sounds App collects basic demographic and medical information from users, as well as spoken voice samples, breathing and coughing samples through the phone’s microphone. The app will also ask users if they have tested positive for the coronavirus.

In addition, the app will collect one coarse grain location sample. The app will not track users, and will only collect location data once when users are actively using it. The data will be stored on University servers and be used solely for research purposes. The app will not provide any medical advice.

Once they have completed their initial analysis of the data collected by the app, the team will release the dataset to other researchers. The dataset could help shed light on disease progression, further relationship of the respiratory complication with medical history, for example.

"Having spoken to doctors, one of the most common things they have noticed about patients with the virus is the way they catch their breath when they’re speaking, as well as a dry cough, and the intervals of their breathing patterns," said Mascolo. "There are very few large datasets of respiratory sounds, so to make better algorithms that could be used for early detection, we need as many samples from as many participants as we can get. Even if we don’t get many positive cases of coronavirus, we could find links with other health conditions."

The study has been approved by the Ethics Committee of the Department of Computer Science and Technology, and is partly funded by the European Research Council through Project EAR.

How you can support Cambridge's COVID-19 research effort

Donate to support COVID-19 research at Cambridge

 

A new app, which will be used to collect data to develop machine learning algorithms that could automatically detect whether a person is suffering from COVID-19 based on the sound of their voice, their breathing and coughing, has been launched by researchers at the University of Cambridge.

Transmission electron microscopic image of an isolate from the first US case of COVID-19

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Shedding light on dark traps

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A multi-institutional collaboration, co-led by scientists at the University of Cambridge and Okinawa Institute of Science and Technology Graduate University (OIST), has identified the source of efficiency-limiting defects in potential materials for next-generation solar cells and LEDs.

In the last decade, perovskites – a diverse range of materials with a specific crystal structure – have emerged as promising alternatives to silicon solar cells, as they are cheaper and greener to manufacture, while achieving a comparable level of efficiency. 

However, perovskites still show significant performance losses and instabilities, particularly in the specific materials that promise the highest ultimate efficiencyMost research to date has focused on ways to remove these losses, but their actual physical causes remain unknown  

Now, in a paper published in Nature, researchers from Dr Sam Stranks’s group at Cambridge’s Department of Chemical Engineering and Biotechnology and Cavendish Laboratoryand Professor Keshav Dani’s Femtosecond Spectroscopy Unit at OIST in Japan, identify the source of the problem. Their discovery could streamline efforts to increase the efficiency of perovskites, bringing them closer to mass-market production.    

Perovskite materials are much more tolerant of defects in their structure than silicon solar cells, and previous research carried out by Stranks’s group found that to a certain extent, some heterogeneity in their composition actually improves their performance as solar cells and light-emitters 

However, the current limitation of perovskite materials is the presence of a 'deep trap' caused by a defect, or minor blemish, in the material. These are areas in the material where energised charge carriers can get stuck and recombine, losing their energy to heat, rather than converting it into useful electricity or light. This recombination process can have a significant impact on the efficiency and stability of solar panels and LEDs.  

Until now, very little was known about the cause of these traps, in part because they appear to behave differently to traps in traditional solar cell materials 

In 2015, Stranks and colleagues published a paper in Science looking at the luminescence of perovskites, which reveals how good they are at absorbing or emitting lightWe found that the material was very heterogeneous; you had quite large regions that were bright and luminescent and other regions that were really dark,” said StranksThese dark regions correspond to power losses in solar cells or LEDs. But what was causing the power loss was always a mysteryespecially because perovskites are otherwise so defect-tolerant. 

Due to limitations of standard imaging techniques, the group couldn’t tell if the darker areas were caused by one, large trap site, or many smaller traps, making it difficult to establish why they were forming only in certain regions 

In 2017, Dani’s group at OIST made movie of how electrons behave in semiconductors after absorbing light. “You can learn a lot from being able to see how charges move in a material or device after shining lightFor example, you can see where they might be getting trapped,” said DaniHowever, these charges are hard to visualise as they move very fast – on the timescale of a millionth of a billionth of a second; and over very short distances – on the length scale of a billionth of a metre.  

On hearing of Dani’s workStranks reached out to see if they could work together to address the problem visualising the dark regions in perovskites 

The team at OIST used a technique called photoemission electron microscopy (PEEM) for the first time on perovskiteswhere they probed the material with ultraviolet light and built up an image based on how the emitted electrons scattered 

When they looked at the material, they found that the dark regions contained traps, around 10-100 nanometers in length, which were clusters of smaller atomic-sized trap sites. These trap clusters were spread unevenly throughout the perovskite material, explaining the heterogeneous luminescence seen in Stranks’s earlier research. 

When the researchers overlaid images of the trap sites onto images that showed the crystal grains of the perovskite material, they found that the trap clusters only formed at specific places, at the boundaries between certain grains. 

To understand why this only occurred at certain grain boundaries, the groups worked together with Professor Paul Midgley’s team from Cambridge’s Department of Materials Science and Metallurgy using a technique called scanning electron diffraction to create detailed images of the perovskite crystal structure. The project team made use of the electron microscopy setup at the ePSIC facility at the Diamond Light Source Synchrotron, which has specialised equipment for imaging beam-sensitive materials, like perovskites.  

“Because these materials are very beam-sensitive, typical techniques that you would use to probe local crystal structure on these length scales will quite quickly change the material as you're looking at it, which can make interpreting the data very difficult,” said Tiarnan Doherty, a PhD student in Strankss group and co-lead author of the study. Instead, we were able to use very low exposure doses and therefore prevent damage.  

From the work at OIST, we knew where the trap clusters were located, and at ePSIC, we scanned around those same areas to see the local structure. We were then able to quickly pinpoint unexpected variations in the crystal structure around the trap clusters. 

The group discovered that the trap clusters only formed at junctions where an area of the material with slightly distorted structure met an area with pristine structure. 

“In perovskites, we have regular mosaic grains of material and most of the grains are nice and pristine – the structure we would expect,” said StranksBut every now and again, you get a grain that's slightly distorted and the chemistry of that grain is inhomogeneous. What was really interesting and which initially confused us was that it's not the distorted grain that's the trap but where that grain meets a pristine grain; it's at that junction that the traps cluster.  

With this understanding of the nature of the trapsthe team at OIST also used the custom-built PEEM instrumentation to visualise the dynamics of the charge carrier trapping process happening in the perovskite material. This was possible as one of the unique features of our PEEM setup is that it can image ultrafast processes – as short as femtoseconds,” said Andrew Winchester, a PhD student in Dani’s Unit, and co-lead author of this study. “We found that the trapping process was dominated by charge carriers diffusing to the trap clusters. 

These discoveries represent a breakthrough in the quest to bring perovskites to the solar energy market.  

We still don't know exactly why the traps are clustering there, but we noknow that they do form there, and seemingly only there,” said StranksThat's exciting because it means we now know what to target to bring up the performances of perovskites. We need to target those inhomogeneous phases or get rid of these junctions in some way. 

“The fact that charge carriers must first diffuse to the traps could also suggest other strategies to improve these devices,” said Dani. “Maybe we could alter or control the arrangement of the trap clusters, without necessarily changing their average number, such that charge carriers are less likely to reach these defect sites.”  

The teams’ research focused on one particular perovskite structureThe scientists will now be investigating whether the cause of these trapping clusters is universal across other perovskite materials.  

“Most of the progress in device performance has been trial and error and so far, this has been quite an inefficient process,” said Stranks. “To date, it really hasn't been driven by knowing a specific cause and systematically targeting that. This is one of the first breakthroughs that will help us to use the fundamental science to engineer more efficient devices.” 

Reference:
Tiarnan A.S. Doherty et al. 'Performance-limiting nanoscale trap clusters at grain junctions in halide perovskites.' Nature (2020). DOI: 10.1038/s41586-020-2184-1

 

Researchers pinpoint the origin of defects that sap the performance of next-generation solar technology.

We now know what to target to bring up the performances of perovskites.
Samuel Stranks
Perovskites

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