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Bringing biology to bricks — concrete details on how to grow building materials – CBC.ca

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A team of American researchers has developed a new kind of biological concrete that could redefine what we mean by “green buildings.” 

The concrete, developed by researchers at the University of Colorado, Boulder, uses bacteria as a binder. This leads to a material that can grow and even heal itself — much like a living organism.

“When we finally hit on a solution that brought the brick to life it really was an ‘aha’ moment,” said Wil Srubar in an interview with Bob McDonald on Quirks & Quarks.

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Srubar is an assistant professor of engineering at the University of Colorado at Boulder, and led the work.

Bringing bricks to life

Concrete is the most widely used man-made material on Earth, but its production has a massive carbon footprint. Cement making is extremely energy intensive and releases large amounts of carbon dioxide. The United Nations Environment Agency has called out for “dramatic action” to reduce this footprint in order to limit global warming.

“In our system, we’re using no cement and we’re actually using an organism that thrives on carbon dioxide to manufacture the materials,” said Srubar.

An arch made from living building materials, next to the bacteria used to make it. (CU Boulder College of Engineering & Applied Science)

In traditional concrete, sand and aggregate are bonded together with cement.

In this biological concrete, photosynthetic cyanobacteria take the place of cement. The bacteria use carbon dioxide from air to produce a material similar to limestone that glues together sand particles, making robust building blocks.

“The photosynthetic cyanobacteria that we use takes CO2, and some nutrients, and they biomineralize,” said Srubar. “It’s similar to a process of making seashells in the oceans.”

“And so it, in effect, creates tiny limestone particles as the glue in our brick.”

Srubar’s process was a little more complicated than simply mixing up a batch of sand and a bacterial culture. The team had to find the right growing conditions for the bacteria, which included appropriate levels of moisture and important nutrients, but still the process was slow.

The ‘living bricks’ seen in their mould. (CU Boulder College of Engineering & Applied Science)

The ultimate key turned out to be adding a jello-like polymer that increased the rate at which the bacteria grew and produced the limestone glue.

A new way to manufacture building materials

Another benefit of using bacteria for concrete is that it can be self-healing, and can replicate itself. Srubar’s team found that when they split a brick in two, they could cause the broken brick to grow in a mould by adding more sand and nutrients — the cyanobacteria would proliferate by themselves. They were able to continue to “grow” new bricks from broken fragments of their biological bricks. 

“So really, what we were demonstrating is a new way to manufacture building materials,” said Srubar.

“Why not leverage something that grows at an exponential rate that self multiplies and use that to manufacture the materials we choose to build?’

A worker pours concrete. Cement is a carbon-intensive industry. (Behrouz Mehri/AFP via Getty Images)

Since traditional cement production is responsible for about six per cent of greenhouse gas emissions, the researchers hope that, by not only substituting this biological cement might some day make a significant dent in how much building materials contribute to global warming.

Srubar also sees a potential future use of his technology being used to build infrastructure on other planets.

“If we had to build a brand new world, we wouldn’t be burning the limestone to make the cement and we wouldn’t be melting the sand to make the glass. I think we would turn to biology to help us grow the materials with which we choose to build.”

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Scientists revive 48500-year-old ‘zombie virus’ buried in ice

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The thawing of ancient permafrost due to climate change may pose a new threat to humans, according to researchers who revived nearly two dozen viruses – including one frozen under a lake more than 48,500 years ago.

European researchers examined ancient samples collected from permafrost in the Siberia region of Russia. They revived and characterized 13 new pathogens, what they termed “zombie viruses,” and found that they remained infectious despite spending many millennia trapped in the frozen ground.

Scientists have long warned that the thawing of permafrost due to atmospheric warming will worsen climate change by freeing previously trapped greenhouse gases like methane. But its effect on dormant pathogens is less well understood.

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The team of researchers from Russia, Germany and France said the biological risk of reanimating the viruses they studied was “totally negligible” due to the strains they targeted, mainly those capable of infecting amoeba microbes. The potential revival of a virus that could infect animals or humans is much more problematic, they said, warning that their work can be extrapolated to show the danger is real.

“It is thus likely that ancient permafrost will release these unknown viruses upon thawing,” they wrote in an article posted to the preprint repository bioRxiv that hasn’t yet been peer-reviewed.

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“How long these viruses could remain infectious once exposed to outdoor conditions, and how likely they will be to encounter and infect a suitable host in the interval, is yet impossible to estimate.”

“But the risk is bound to increase in the context of global warming when permafrost thawing will keep accelerating, and more people will be populating the Arctic in the wake of industrial ventures,” they said.

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McMaster University team to finalize plans with CSA on deployment of satellite

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A team of students from McMaster University which has spent close to seven years creating a satellite to measure space radiation is set to finalize plans to deploy the device in outer space.

The Canadian Space Agency (CSA) is welcoming the developers this week to finalize preparation of their CubeSat, a miniaturized satellite to further the understanding of long-term exposure to space radiation.

Operation Team Lead with McMaster’s NEUtron DOSimetry & Exploration (NEUDOSE) mission Taren Ginter says the idea was selected for the Canadian Cube Sat project in 2018. In simple terms, Ginter says it measures the effects of ionizing radiation on the human body.

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Some of the financial backing for the project came in the form of $200,000 awarded to the McMaster developers by the CSA.

Ginter says as spaceflight and deep-space missions become a reality in the future, astronauts will likely have to face radiation that is distinct from the radiation experienced on earth.

The question the NEUDOSE mission is looking to answer is what kind and how much radiation astronauts will face on a multi-year mission in space.

“So our goal is to get a sense of those radiation differences and hopefully we can implement better safety precautions so that astronauts are protected,” Ginter explained.

The McMaster radiation detector is the size of a loaf of bread and is expected to be placed in a small satellite prior to being deployed into space, free floating like an astronaut would.

If it works properly, the device will send real-time radiation measurements back to the team at the university.

The device is the concept of Dr. Andrei Hanu, who came up with the idea while working at NASA as a research scientist.

Hanu led the first team of developers in 2015, jokingly referring to the device as the “igloo” due to its top which is dome-shaped.

However, Ginter says the satellite will actually look like a bunch of solar panels connected together due to the fact it needs to be charged by sunlight.

“But inside of the satellite, we have our charged and neutral particle tissue equivalent proportional counter, which is quite a mouthful,” Ginter said.

“So this is the actual payload of our satellite that will be looking at the radiation in low-earth orbit and then sending that information back down to ground station at McMaster.”

The NEUDOSE CubeSat will head to the CSA this week for a final step confirming it meets standards to be deployed from the International Space Station (ISS).

The life expectancy of the device is approximately one year in the Earth’s orbit after it’s been deployed.

The McMaster creation is earmarked for the ISS in February following launch from a SpaceX Dragon ship in Florida.

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Explainable AI-based physical theory for advanced materials design: Scientists develop an ‘extended Landau free energy model’ for causal analysis and visualization in nano-magnetic devices with AI and topology

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Microscopic materials analysis is essential to achieve desirable performance in next-generation nanoelectronic devices, such as low power consumption and high speeds. However, the magnetic materials involved in such devices often exhibit incredibly complex interactions between nanostructures and magnetic domains. This, in turn, makes functional design challenging.

Traditionally, researchers have performed a visual analysis of the microscopic image data. However, this often makes the interpretation of such data qualitative and highly subjective. What is lacking is a causal analysis of the mechanisms underlying the complex interactions in nanoscale magnetic materials.

In a recent breakthrough published in Scientific Reports, a team of researchers led by Prof. Masato Kotsugi from Tokyo University of Science, Japan succeeded in automating the interpretation of the microscopic image data. This was achieved using an “extended Landau free energy model” that the team developed using a combination of topology, data science, and free energy. The model could illustrate the physical mechanism as well as the critical location of the magnetic effect, and proposed an optimal structure for a nano device. The model used physics-based features to draw energy landscapes in the information space, which could be applied to understand the complex interactions at the nanoscales in a wide variety of materials.

“Conventional analysis are based on a visual inspection of microscope images, and the relationships with the material function are expressed only qualitatively, which is a major bottleneck for material design. Our extended Landau free energy model enables us to identify the physical origin and location of the complex phenomena within these materials. This approach overcomes the explainability problem faced by deep learning, which, in a way, amounts to reinventing new physical laws,” Prof. Kotsugi explains. This work was supported by KAKENHI, JSPS, and the MEXT-Program for Creation of Innovative Core Technology for Power Electronics Grant.

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When designing the model, the team made use of the state-of-art technique in the fields of topology and data science to extend the Landau free energy model. This led to a model that enabled a causal analysis of the magnetization reversal in nanomagnets. The team then carried out an automated identification of the physical origin and visualization of the original magnetic domain images.

Their results indicated that the demagnetization energy near a defect gives rise to a magnetic effect, which is responsible for the “pinning phenomenon.” Further, the team could visualize the spatial concentration of energy barriers, a feat that had not been achieved until now. Finally, the team proposed a topologically inverse design of recording devices and nanostructures with low power consumption.

The model proposed in this study is expected to contribute to a wide range of applications in the development of spintronic devices, quantum information technology, and Web 3.

“Our proposed model opens up new possibilities for optimization of magnetic properties for material engineering. The extended method will finally allow us to clarify ‘why’ and ‘where’ the function of a material is expressed. The analysis of material functions, which used to rely on visual inspection, can now be quantified to make precise functional design possible,” concludes an optimistic Prof. Kotsugi.

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