Category Archives: environment

Concrete collapse and research into durability

I have two items about concrete buildings, one concerns the June 24, 2021 collapse of a 12-storey condominium building in Surfside, close to Miami Beach in Florida. There are at least 20 people dead and, I believe, over 120 are still unaccounted for (July 2, 2021 Associated Press news item on Canadian Broadcasting Corporation news online website).

Miami collapse

Nate Berg’s June 25, 2021 article for Fast Company provides an instructive overview of the building collapse (Note: A link has been removed),

Why the building collapsed is not yet known [emphasis mine]. David Darwin is a professor of civil engineering at the University of Kansas and an expert in reinforced concrete structures, and he says the eventual investigation of the Surfside collapse will explore all the potential causes, ranging from movement in the foundation before the collapse, corrosion in the debris, and excessive cracking in the part of the building that remains standing. “There are all sorts of potential causes of failure,” Darwin says. “At this point, speculation is not helpful for anybody.”

Sometimes I can access the entire article, and at other times, only a few paragraphs; I hope you get access to all of it as it provides a lot of information.

The Surfside news puts this research from Northwestern University (Chicago, Illinois) into much sharper relief than might otherwise be the case. (Further on I have some information about the difference between cement and concrete and how cement leads to concrete.)

Smart cement for more durable roads and cities

Coincidentally, just days before the Miami Beach building collapse, a June 21, 2021 Northwestern University news release (also on EurekAlert), announced research into improving water and fracture resistance in cement,

Forces of nature have been outsmarting the materials we use to build our infrastructure since we started producing them. Ice and snow turn major roads into rubble every year; foundations of houses crack and crumble, in spite of sturdy construction. In addition to the tons of waste produced by broken bits of concrete, each lane-mile of road costs the U.S. approximately $24,000 per year to keep it in good repair.

Engineers tackling this issue with smart materials typically enhance the function of materials by increasing the amount of carbon, but doing so makes materials lose some mechanical performance. By introducing nanoparticles into ordinary cement, Northwestern University researchers have formed a smarter, more durable and highly functional cement.

The research was published today (June 21 [2021]) in the journal Philosophical Transactions of the Royal Society A.

With cement being the most widely consumed material globally and the cement industry accounting for 8% of human-caused greenhouse gas emissions, civil and environmental engineering professor Ange-Therese Akono turned to nanoreinforced cement to look for a solution. Akono, the lead author on the study and an assistant professor in the McCormick School of Engineering, said nanomaterials reduce the carbon footprint of cement composites, but until now, little was known about its impact on fracture behavior.

“The role of nanoparticles in this application has not been understood before now, so this is a major breakthrough,” Akono said. “As a fracture mechanics expert by training, I wanted to understand how to change cement production to enhance the fracture response.”

Traditional fracture testing, in which a series of light beams is cast onto a large block of material, involves lots of time and materials and seldom leads to the discovery of new materials.

By using an innovative method called scratch testing, Akono’s lab efficiently formed predictions on the material’s properties in a fraction of the time. The method tests fracture response by applying a conical probe with increasing vertical force against the surface of microscopic bits of cement. Akono, who developed the novel method during her Ph.D. work, said it requires less material and accelerates the discovery of new ones.

“I was able to look at many different materials at the same time,” Akono said. “My method is applied directly at the micrometer and nanometer scales, which saves a considerable amount of time. And then based on this, we can understand how materials behave, how they crack and ultimately predict their resistance to fracture.”

Predictions formed through scratch tests also allow engineers to make changes to materials that enhance their performance at the larger scale. In the paper, graphene nanoplatelets, a material rapidly gaining popularity in forming smart materials, were used to improve the resistance to fracture of ordinary cement. Incorporating a small amount of the nanomaterial also was shown to improve water transport properties including pore structure and water penetration resistance, with reported relative decreases of 76% and 78%, respectively.

Implications of the study span many fields, including building construction, road maintenance, sensor and generator optimization and structural health monitoring.

By 2050, the United Nations predicts two-thirds of the world population will be concentrated in cities. Given the trend toward urbanization, cement production is expected to skyrocket.

Introducing green concrete that employs lighter, higher-performing cement will reduce its overall carbon footprint by extending maintenance schedules and reducing waste.

Alternately, smart materials allow cities to meet the needs of growing populations in terms of connectivity, energy and multifunctionality. Carbon-based nanomaterials including graphene nanoplatelets are already being considered in the design of smart cement-based sensors for structural health monitoring.

Akono said she’s excited for both follow-ups to the paper in her own lab and the ways her research will influence others. She’s already working on proposals that look into using construction waste to form new concrete and is considering “taking the paper further” by increasing the fraction of nanomaterial that cement contains.

“I want to look at other properties like understanding the long-term performance,” Akono said. “For instance, if you have a building made of carbon-based nanomaterials, how can you predict the resistance in 10, 20 even 40 years?”

The study, “Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing,” was supported by the National Science Foundation Division of Civil, Mechanical and Manufacturing Innovation (award number 18929101).

Akono will give a talk on the paper at The Royal Society’s October [2021] meeting, “A Cracking Approach to Inventing Tough New Materials: Fracture Stranger Than Friction,” which will highlight major advances in fracture mechanics from the past century.

I don’t often include these kinds of photos (one or more of the researchers posing (sometimes holding something) for the camera but I love the professor’s first name, Ange-Therese (which means angel in French, I don’t know if she ever uses the French spelling for Thérèse),

Caption: Professor Ange-Therese Akono holds a sample of her smart cement. Credit: Northwestern University

Here’s a link to and a citation for the paper,

Fracture toughness of one- and two-dimensional nanoreinforced cement via scratch testing by Ange-Therese Akono. Philosophical Transactions of the Royal Society A: Mathematical, Physical & Engineering Sciences 2021 379 (2203): 20200288 DOI: 10.1098/rsta.2020.0288 Published June 21, 2021

This paper appears to be open access.

Cement vs. concrete

Andrew Logan’s April 3, 2020 article for MIT (Massachusetts Institute of Technology) News is a very readable explanation of how cement and concrete differ and how they are related,

There’s a lot the average person doesn’t know about concrete. For example, it’s porous; it’s the world’s most-used material after water; and, perhaps most fundamentally, it’s not cement.

Though many use “cement” and “concrete” interchangeably, they actually refer to two different — but related — materials: Concrete is a composite made from several materials, one of which is cement. [emphasis mine]

Cement production begins with limestone, a sedimentary rock. Once quarried, it is mixed with a silica source, such as industrial byproducts slag or fly ash, and gets fired in a kiln at 2,700 degrees Fahrenheit. What comes out of the kiln is called clinker. Cement plants grind clinker down to an extremely fine powder and mix in a few additives. The final result is cement.

“Cement is then brought to sites where it is mixed with water, where it becomes cement paste,” explains Professor Franz-Josef Ulm, faculty director of the MIT Concrete Sustainability Hub (CSHub). “If you add sand to that paste it becomes mortar. And if you add to the mortar large aggregates — stones of a diameter of up to an inch — it becomes concrete.”

Final thoughts

I offer my sympathies to the folks affected by the building collapse and my hopes that research will lead the way to more durable cement and, ultimately, concrete buildings.

Fish DJ makes discoveries about fish hearing

A March 2, 2021 University of Queensland press release (also on EurekAlert) announces research into how fish brains develop and how baby fish hear,

A DJ-turned-researcher at The University of Queensland has used her knowledge of cool beats to understand brain networks and hearing in baby fish

The ‘Fish DJ’ used her acoustic experience to design a speaker system for zebrafish larvae and discovered that their hearing is considerably better than originally thought.

This video clip features zebrafish larvae listening to music, MC Hammer’s ‘U Can’t Touch This’ (1990),

Here’s the rest of the March 2, 2021 University of Queensland press release,

PhD candidate Rebecca Poulsen from the Queensland Brain Institute said that combining this new speaker system with whole-brain imaging showed how larvae can hear a range of different sounds they would encounter in the wild.

“For many years my music career has been in music production and DJ-ing — I’ve found underwater acoustics to be a lot more complicated than air frequencies,” Ms Poulsen said.

“It is very rewarding to be using the acoustic skills I learnt in my undergraduate degree, and in my music career, to overcome the challenge of delivering sounds to our zebrafish in the lab.

“I designed the speaker to adhere to the chamber the larvae are in, so all the sound I play is accurately received by the larvae, with no loss through the air.”

Ms Poulsen said people did not often think about underwater hearing, but it was crucial for fish survival – to escape predators, find food and communicate with each other.

Ms Poulsen worked with Associate Professor Ethan Scott, who specialises in the neural circuits and behaviour of sensory processing, to study the zebrafish and find out how their neurons work together to process sounds.

The tiny size of the zebrafish larvae allows researchers to study their entire brain under a microscope and see the activity of each brain cell individually.

“Using this new speaker system combined with whole brain imaging, we can see which brain cells and regions are active when the fish hear different types of sounds,” Dr Scott said.

The researchers are testing different sounds to see if the fish can discriminate between single frequencies, white noise, short sharp sounds and sound with a gradual crescendo of volume.

These sounds include components of what a fish would hear in the wild, like running water, other fish swimming past, objects hitting the surface of the water and predators approaching.

“Conventional thinking is that fish larvae have rudimentary hearing, and only hear low-frequency sounds, but we have shown they can hear relatively high-frequency sounds and that they respond to several specific properties of diverse sounds,” Dr Scott said.

“This raises a host of questions about how their brains interpret these sounds and how hearing contributes to their behaviour.”

Ms Poulsen has played many types of sounds to the larvae to see which parts of their brains light up, but also some music – including MC Hammer’s “U Can’t Touch This”– that even MC Hammer himself enjoyed.

The March 3, 3021 story by Graham Readfearn originally published by The Guardian (also found on MSN News), has more details about the work and the researcher,

As Australia’s first female dance music producer and DJ, Rebecca Poulsen – aka BeXta – is a pioneer, with scores of tracks, mixes and hundreds of gigs around the globe under her belt.

But between DJ gigs, the 46-year-old is now back at university studying neuroscience at Queensland Brain Institute at the University of Queensland in Brisbane.

And part of this involves gently securing baby zebrafish inside a chamber and then playing them sounds while scanning their brains with a laser and looking at what happens through a microscope.

The analysis for the study doesn’t look at how the fish larvae react during Hammer [MC Hammer] time, but how their brain cells react to simple single-frequency sounds.

“It told us their hearing range was broader than we thought it was before,” she says.

Poulsen also tried more complex sounds, like white noise and “frequency sweeps”, which she describes as “like the sound when Wile E Coyote falls off a cliff” in the Road Runner cartoons.

“When you look at the neurons that light up at each sound, they’re unique. The fish can tell the difference between complex and different sounds.”

This is, happily, where MC Hammer comes in.

Out of professional and scientific curiosity – and also presumably just because she could – Poulsen played music to the fish.

She composed her own piece of dance music and that did seem to light things up.

But what about U Can’t Touch This?

“You can see when the vocal goes ‘ohhh-oh’, specific neurons light up and you can see it pulses to the beat. To me it looks like neurons responding to different parts of the music.

“I do like the track. I was pretty little when it came out and I loved it. I didn’t have the harem pants, though, but I did used to do the dance.”

How do you stop the fish from swimming away while you play them sounds? And how do you get a speaker small enough to deliver different volumes and frequencies without startling the fish?

For the first problem, the baby zebrafish – just 3mm long – are contained in a jelly-like substance that lets them breathe “but stops them from swimming away and keeps them nice and still so we can image them”.

For the second problem, Poulsen and colleagues used a speaker just 1cm wide and stuck it to the glass of the 2cm-cubed chamber the fish was contained in.

Using fish larvae has its advantages. “They’re so tiny we can see their whole brain … we can see the whole brain live in real time.”

If you have the time, I recommend reading Readfearn’s March 3, 3021 story in its entirety.

Poulsen as Bexta has a Wikipedia entry and I gather from Readfearn’s story that she is still active professionally.

Here’s a link to and a citation for the published paper,

Broad frequency sensitivity and complex neural coding in the larval zebrafish auditory system by Rebecca E. Poulsen, Leandro A. Scholz, Lena Constantin, Itia Favre-Bulle, Gilles C. Vanwalleghem, Ethan K. Scott. Current Biology DOI:https://doi.org/10.1016/j.cub.2021.01.103 Published: March 02, 2021

This paper appears to be open access.

There is an earlier version of the paper on bioRxiv made available for open peer review. Oddly, I don’t see any comments but perhaps I need to login.

Related research but not the same

I was surprised when a friend of mine in early January 2021 needed to be persuaded that noise in aquatic environments is a problem. If you should have any questions or doubts, perhaps this March 4, 2021 article by Amy Noise (that is her name) on the Research2Reality website can answer them,

Ever had builders working next door? Or a neighbour leaf blowing while you’re trying to make a phone call? Unwanted background noise isn’t just stressful, it also has tangible health impacts – for both humans and our marine cousins.

Sound travels faster and farther in water than in air. For marine creatures who rely heavily on sound, crowded ocean soundscapes could be more harmful than previously thought.

Marine animals use sound to navigate, communicate, find food and mates, spot predators, and socialize. But since the Industrial Revolution, humans have made the planet, and the oceans in particular, exponentially noisier.

From shipping and fishing, to mining and sonar, underwater anthropogenic noise is becoming louder and more prevalent. While parts of the ocean’s chorus are being drowned out, others are being permanently muted through hunting and habitat loss.

[An] international team, including University of Victoria biologist Francis Juanes, reviewed over 10,000 papers from the past 40 years. They found overwhelming evidence that anthropogenic noise is negatively impacting marine animals.

Getting back to Poulsen and Queensland, her focus is on brain development not noise although I imagine some of her work may be of use to researchers investigating anthropogenic noise and its impact on aquatic life.

Making carbon capture more efficient and cheaper with graphene filters

Years ago someone asked me if there was any nanotechnology research into carbon capture. I couldn’t answer the question at the time but since then I’ve been on the lookout for more on the topic. So, I’m happy to add this February 25, 2021 news item on Nanowerk to my growing number of carbon capture posts (Note: A link has been removed),

One of the main culprits of global warming is the vast amount of carbon dioxide pumped out into the atmosphere mostly from burning fossil fuels and the production of steel and cement. In response, scientists have been trying out a process that can sequester waste carbon dioxide, transporting it into a storage site, and then depositing it at a place where it cannot enter the atmosphere.

The problem is that capturing carbon from power plants and industrial emissions isn’t very cost-effective. The main reason is that waste carbon dioxide isn’t emitted pure, but is mixed with nitrogen and other gases, and extracting it from industrial emissions requires extra energy consumption – meaning a pricier bill.

Scientists have been trying to develop an energy-efficient carbon dioxide-filter. Referred to as a “membrane”, this technology can extract carbon dioxide out of the gas mix, which can then be either stored or converted into useful chemicals. “However, the performance of current carbon dioxide filters has been limited by the fundamental properties of currently available materials,” explains Professor Kumar Varoon Agrawal at EPFL’s School of Basic Sciences (EPFL Valais Wallis).

Now, Agrawal has led a team of chemical engineers to develop the world’s thinnest filter from graphene, the world-famous “wonder material” that won the Physics Nobel in 2010. But the graphene filter isn’t just the thinnest in the world, it can also separate carbon dioxide from a mix of gases such as those coming out of industrial emissions and do so with an efficiency and speed that surpasses most current filters.

A March 3, 2021 Ecole Polytechnique Fédérale de Lausanne (EPFL) press release (also on EurekAlert but published February 25, 2021), which originated the news item, delves further into the topic,

“Our approach was simple,” says Agrawal. “We made carbon dioxide-sized holes in graphene, which allowed carbon dioxide to flow through while blocking other gases such as nitrogen, which are larger than carbon dioxide.” The result is a record-high carbon dioxide-capture performance.

For comparison, current filters are required to exceed 1000 gas permeation units (GPUs), while their carbon-capturing specificity, referred to as their “carbon dioxide/nitrogen separation factor” must be above 20. The membranes that the EPFL scientists developed show more than ten-fold higher carbon dioxide permeance at 11,800 GPUs, while their separation factor stands at 22.5.

“We estimate that this technology will drop the cost of carbon capture close to $30 per ton of carbon dioxide, in contrast to commercial processes where the cost is two-to-four time higher,” says Agrawal. His team is now working on scaling up the process by developing a pilot plant demonstrator to capture 10 kg carbon dioxide per day, in a project funded by the Swiss government and Swiss industry.

Here’s a link to and a citation for the paper,

Millisecond lattice gasification for high-density CO2– and O2-sieving nanopores in single-layer graphene by Shiqi Huang, Shaoxian Li, Luis Francisco Villalobos, Mostapha Dakhchoune, Marina Micari, Deepu J. Babu, Mohammad Tohidi Vahdat, Mounir Mensi, Emad Oveisi and Kumar Varoon Agrawal. Science Advances 24 Feb 2021: Vol. 7, no. 9, eabf0116 DOI: 10.1126/sciadv.abf0116

This paper appears to be open access.

Sunlight makes transparent wood even lighter and stronger

Researchers at the University of Maryland (US) have found a way to make their wood transparent by using sunlight. From a February 2, 2021 news article by Bob Yirka on phys.org (Note: Links have been removed),

A team of researchers at the University of Maryland, has found a new way to make wood transparent. In their paper published in the journal Science Advances, the group describes their process and why they believe it is better than the old process.

The conventional method for making wood transparent involves using chemicals to remove the lignin—a process that takes a long time, produces a lot of liquid waste and results in weaker wood. In this new effort, the researchers have found a way to make wood transparent without having to remove the lignin.

The process involved changing the lignin rather than removing it. The researchers removed lignin molecules that are involved in producing wood color. First, they applied hydrogen peroxide to the wood surface and then exposed the treated wood to UV light (or natural sunlight). The wood was then soaked in ethanol to further clean it. Next, they filled in the pores with clear epoxy to make the wood smooth.

Caption: Solar-assisted large-scale fabrication of transparent wood. (A) Schematic showing the potential large-scale fabrication of transparent wood based on the rotary wood cutting method and the solar-assisted chemical brushing process. (B) The outdoor fabrication of lignin-modified wood with a length of 1 m [9 August 2019 (the summer months) at 13:00 p.m. (solar noon), the Global Solar UV Index (UVI): 7 to 8]. (C) Digital photo of a piece of large transparent wood (400 mm by 110 mm by 1 mm). (D) The energy consumption, chemical cost, and waste emission for the solar-assisted chemical brushing process and NaClO2 solution–based delignification process. (E) A radar plot showing a comparison of the fabrication process for transparent wood. Photo credit: Qinqin Xia, University of Maryland, College Park. [downloaded from https://advances.sciencemag.org/content/7/5/eabd7342]

Bob McDonald in a February 5, 2021 posting on his Canadian Broadcasting Corporation (CBC) Quirks & Quarks blog provides a more detailed description of the new ‘solar-based transparency process’,

Early attempts to make transparent wood involved removing the lignin, but this involved hazardous chemicals, high temperatures and a lot of time, making the product expensive and somewhat brittle. The new technique is so cheap and easy it could literally be done in a backyard.

Starting with planks of wood a metre long and one millimetre thick, the scientists simply brushed on a solution of hydrogen peroxide using an ordinary paint brush. When left in the sun, or under a UV lamp for an hour or so, the peroxide bleached out the brown chromophores but left the lignin intact, so the wood turned white.

Next, they infused the wood with a tough transparent epoxy designed for marine use, which filled in the spaces and pores in the wood and then hardened. This made the white wood transparent.

As window material, it would be much more resistant to accidental breakage. The clear wood is lighter than glass, with better insulating properties, which is important because windows are a major source of heat loss in buildings. It also might take less energy to manufacture clear wood because there are no high temperatures involved.

Many different types of wood, from balsa to oak, can be made transparent, and it doesn’t matter if it is cut along the grain or against it. If the transparent wood is made a little thicker, it would be strong enough to become part of the structure of a building, so there could be entire transparent wooden walls.

Adele Peters in her February 2, 2021 article for Fast Company describes the work in Maryland and includes some information about other innovative and possibly sustainable uses of wood (Note: Links have been removed),

It’s [transparent wood] just one of a number of ways scientists and engineers are rethinking how we can use this renewable resource in construction. Skyscrapers made entirely out of wood are gaining popularity in cities around the world. And scientists recently discovered a technique to grow wood in a lab, opening up the possibility of using wood without having to chop down a forest.

There were three previous posts here about this work at the University of Maryland,

University of Maryland looks into transparent wood May 11, 2016 posting

Transparent wood more efficient than glass in windows? Sept, 8, 2016 posting

Glass-like wood windows protect against UV rays and insulate heat October 21, 2020 posting

I have this posting, which is also from 2016 but features work in Sweden,

Transparent wood instead of glass for window panes? April 1, 2016 posting

Getting back to the latest work from the University of Maryland, here’s a link to and a citation for the paper,

Solar-assisted fabrication of large-scale, patternable transparent wood by Qinqin Xia, Chaoji Chen, Tian Li, Shuaiming He, Jinlong Gao, Xizheng Wang and Liangbing Hu. Science Advances Vol. 7, no. 5, eabd7342 DOI: 10.1126/sciadv.abd7342 Published: 27 Jan 2021

This paper is open access.

One last item, Liangbing Hu has founded a company InventWood for commercializing the work he and his colleagues have done at the University of Maryland.

“Wolves, Livestock, and the Physical and Social Environments,” an April 14, 2021 event in celebration of Italian Research in the World Day

ARPICO (Society of Italian Researchers & Professionals in Western Canada) is presenting a pre-celebration event to honour Italian Research in the World Day (April 15, 2021). Take special note: the event is being held the day before.

Before launching into the announcement, bravo to the organizers! ARPICO consistently offers the most comprehensive details about their events of any group that contacts me. One more thing, to date, they are the only group that have described which technology they’re using for the webcast and explicitly address any concerns about downloading software (you don’t have to) or about personal information. (Check out Technical Instruction here.)

Here are the details from ARPICO’s April 4, 2021 announcement (received via email),

We hope everyone is doing well and being safe while we attempt to outlast this pandemic. In the meanwhile, from the comfort of our homes, we hope to be able to continue to share with you informative lectures to entertain and stimulate thought.

It is our pleasure, in collaboration with the Consulate General of Italy in Vancouver, to announce that ARPICO’s next public event will be held on April 14th, 2021 at 7:00 PM, in celebration of Italian Research in the World Day. Italian Research in the World Day was instituted starting in 2018 as part of the Piano Straordinario “Vivere all’Italiana” – Giornata della ricerca Italiana nel mondo. The celebration day was chosen by government decree to be every year on April 15 on the anniversary of the birth of Leonardo da Vinci.

The main objective of the Italian Research Day in the World is to value the quality and competencies of Italian researchers abroad, but also to promote concrete actions and investments to allow Italian researchers to continue pursuing their careers in their homeland. Italy wishes to enable Italian talents to return from abroad as well as to become an attractive environment for foreign researchers.

This year we are pleased to have Professor Marco Musiani, an academic in biological sciences, share with us a lecture titled “Wolves, Livestock, and the Physical and Social Environments.” An abstract and short professional biography are provided below.

We have chosen BlueJeans as the videoconferencing platform, for which you will only require a web browser (Chrome, Firefox, Edge, Safari, Opera are all supported). Full detailed instructions on how the virtual event will unfold are available on the EventBrite listing here in the Technical Instruction section.

If participants wish to donate to ARPICO, this can be done within EventBrite; this would be greatly appreciated in order to help us continue to build upon our scholarship fund, and to defray the cost of the videoconferencing license.

We look forward to seeing everyone there.

The evening agenda is as follows:

  • 6:45PM – BlueJeans Presentation link becomes active and registrants may join.
    • If you experience any technical details please email us at info@arpico.ca and we will attempt to assist you as best we can.
  • 7:00pm – Start of the evening Event with introductions & lecture by Prof. Marco Musiani
  • ~8:00 pm – Q & A Period via BlueJeans Chat Interface

If you have not already done so, please register for the event by visiting the EventBrite link or RSVPing to info@arpico.ca.

Further details are also available at arpico.ca and Eventbrite.

Wolves, Livestock, and the Physical and Social Environments

Due primarily to wolf predation on livestock (depredation), some groups oppose wolf (Canis lupus) conservation, which is an objective for large sectors of the public. Prof. Musiani’s talk will compare wolf depredation of sheep in Southern Europe to wolf depredation of beef cattle in the US and Canada, taking into account the differences in social and economic contexts. It will detail where and when wolf attacks happen, and what environmental factors promote such attacks. Livestock depredation by wolves is a cost of wolf conservation borne by livestock producers, which creates conflict between producers, wolves and organizations involved in wolf conservation and management. Compensation is the main tool used to mitigate the costs of depredation, but this tool may be limited at improving tolerance for wolves. In poorer countries compensation funds might not be available. Other lethal and nonlethal tools used to manage the problem will also be analysed. Wolf depredation may be a small economic cost to the industry, although it may be a significant cost to affected producers as these costs are not equitably distributed across the industry. Prof. Musiani maintains that conservation groups should consider the potential consequences of all of these ecological and economic trends. Specifically, declining sheep or cattle price and the steady increase in land price might induce conversion of agricultural land to rural-residential developments, which could negatively impact the whole environment via large scale habitat change and increased human presence.

Marco Musiani is a Professor in the Dept. of Biological Sciences, Faculty of Science, University of Calgary. He also has a Joint Appointment with the Faculty of Veterinary Medicine in Calgary. His lab has a strong focus on landscape ecology, molecular ecology, and wildlife conservation.

Marco is Principal Investigator on projects on caribou, elk, moose, wolves, grizzlies and other wildlife species throughout the Rocky Mountains and Foothills regions of Canada. All such projects are run together with graduate students and have applications towards impact assessment, mainly of human infrastructure.

His focus is on academic matters. However, he also serves as reviewer for research and management projects, and acted as a consultant for the Food and Agriculture Organisation of the United Nations (working on conflicts with wolves).

WHEN (EVENT): Wed, April 14th, 2021 at 7:00PM (BlueJeans link active at 6:45PM)

WHERE: Online using the BlueJeans Conferencing platform.

RSVP: Please register for tickets at EventBrite

Tickets are Needed

Tickets for this event are FREE. Due to limited seating at the venue, we ask that each household register once and watch the presentation together on a single device.       You will receive the event videoconferencing invite link via email in your registration confirmation.

FAQs

  • Where can I contact the organizer with any questions? info@arpico.ca
  • Can I update my registration information? Yes. If you have any questions, contact us at info@arpico.ca
  • I am having trouble using EventBrite and cannot reserve my ticket(s). Can someone at ARPICO help me with my ticket reservation? Of course, simply send your ticket request to us at info@arpico.ca so we help you.

You can find the programme announcement on this ARPICO event page.

Use kombucha to produce bacterial cellulose

The combination of the US Army, bacterial cellulose, and kombucha seems a little unusual. However, this January 26, 2021 U.S. Army Research Laboratory news release (also on EurekAlert) provides some clues as to how this combination makes sense,

Kombucha tea, a trendy fermented beverage, inspired researchers to develop a new way to generate tough, functional materials using a mixture of bacteria and yeast similar to the kombucha mother used to ferment tea.

With Army funding, using this mixture, also called a SCOBY, or symbiotic culture of bacteria and yeast, engineers at MIT [Massachusetts Institute of Technology] and Imperial College London produced cellulose embedded with enzymes that can perform a variety of functions, such as sensing environmental pollutants and self-healing materials.

The team also showed that they could incorporate yeast directly into the cellulose, creating living materials that could be used to purify water for Soldiers in the field or make smart packaging materials that can detect damage.

“This work provides insights into how synthetic biology approaches can harness the design of biotic-abiotic interfaces with biological organization over multiple length scales,” said Dr. Dawanne Poree, program manager, Army Research Office, an element of the U.S. Army Combat Capabilities Development Command, now known as DEVCOM, Army Research Laboratory. “This is important to the Army as this can lead to new materials with potential applications in microbial fuel cells, sense and respond systems, and self-reporting and self-repairing materials.”

The research, published in Nature Materials was funded by ARO [Army Research Office] and the Army’s Institute for Soldier Nanotechnologies [ISN] at the Massachusetts Institute of Technology. The U.S. Army established the ISN in 2002 as an interdisciplinary research center devoted to dramatically improving the protection, survivability, and mission capabilities of the Soldier and Soldier-supporting platforms and systems.

“We foresee a future where diverse materials could be grown at home or in local production facilities, using biology rather than resource-intensive centralized manufacturing,” said Timothy Lu, an MIT associate professor of electrical engineering and computer science and of biological engineering.

Researchers produced cellulose embedded with enzymes, creating living materials that could be used to purify water for Soldiers in the field or make smart packaging materials that can detect damage. These fermentation factories, which usually contain one species of bacteria and one or more yeast species, produce ethanol, cellulose, and acetic acid that gives kombucha tea its distinctive flavor.

Most of the wild yeast strains used for fermentation are difficult to genetically modify, so the researchers replaced them with a strain of laboratory yeast called Saccharomyces cerevisiae. They combined the yeast with a type of bacteria called Komagataeibacter rhaeticus that their collaborators at Imperial College London had previously isolated from a kombucha mother. This species can produce large quantities of cellulose.

Because the researchers used a laboratory strain of yeast, they could engineer the cells to do any of the things that lab yeast can do, such as producing enzymes that glow in the dark, or sensing pollutants or pathogens in the environment. The yeast can also be programmed so that they can break down pollutants/pathogens after detecting them, which is highly relevant to Army for chem/bio defense applications.

“Our community believes that living materials could provide the most effective sensing of chem/bio warfare agents, especially those of unknown genetics and chemistry,” said Dr. Jim Burgess ISN program manager for ARO.

The bacteria in the culture produced large-scale quantities of tough cellulose that served as a scaffold. The researchers designed their system so that they can control whether the yeast themselves, or just the enzymes that they produce, are incorporated into the cellulose structure. It takes only a few days to grow the material, and if left long enough, it can thicken to occupy a space as large as a bathtub.

“We think this is a good system that is very cheap and very easy to make in very large quantities,” said MIT graduate student and the paper’s lead author, Tzu-Chieh Tang. To demonstrate the potential of their microbe culture, which they call Syn-SCOBY, the researchers created a material incorporating yeast that senses estradiol, which is sometimes found as an environmental pollutant. In another version, they used a strain of yeast that produces a glowing protein called luciferase when exposed to blue light. These yeasts could be swapped out for other strains that detect other pollutants, metals, or pathogens.

The researchers are now looking into using the Syn-SCOBY system for biomedical or food applications. For example, engineering the yeast cells to produce antimicrobials or proteins that could benefit human health.

Here’s a link to and a citation for the paper,

Living materials with programmable functionalities grown from engineered microbial co-cultures by Charlie Gilbert, Tzu-Chieh Tang, Wolfgang Ott, Brandon A. Dorr, William M. Shaw, George L. Sun, Timothy K. Lu & Tom Ellis. Nature Materials (2021) DOI: https://doi.org/10.1038/s41563-020-00857-5 Published: 11 January 2021

This paper is behind a paywall.

Baby steps toward a quantum brain

My first quantum brain posting! (Well, I do have something that seems loosely related in a July 5, 2017 posting about quantum entanglement and machine learning and more. Also, I have lots of item on brainlike or neuromorphic computing.)

Getting to the latest news, a February 1, 2021 news item on Nanowerk announces research in to new intelligent materials that could lead to a ‘quantum brain’,

An intelligent material that learns by physically changing itself, similar to how the human brain works, could be the foundation of a completely new generation of computers. Radboud [university in the Netherlands] physicists working toward this so-called “quantum brain” have made an important step. They have demonstrated that they can pattern and interconnect a network of single atoms, and mimic the autonomous behaviour of neurons and synapses in a brain.

If I understand the difference between the work in 2017 and this latest work, it’s that in 2017 they were looking at quantum states and their possible effect on machine learning, while this work in 2021 is focused on a new material with some special characteristics.

A February 1, 2021 Radboud University press release (also on EurekAlert), which originated the news item, provides information on the case supporting the need for a quantum brain and some technical details about how it might be achieved,

Considering the growing global demand for computing capacity, more and more data centres are necessary, all of which leave an ever-expanding energy footprint. ‘It is clear that we have to find new strategies to store and process information in an energy efficient way’, says project leader Alexander Khajetoorians, Professor of Scanning Probe Microscopy at Radboud University.

‘This requires not only improvements to technology, but also fundamental research in game changing approaches. Our new idea of building a ‘quantum brain’ based on the quantum properties of materials could be the basis for a future solution for applications in artificial intelligence.’

Quantum brain

For artificial intelligence to work, a computer needs to be able to recognise patterns in the world and learn new ones. Today’s computers do this via machine learning software that controls the storage and processing of information on a separate computer hard drive. ‘Until now, this technology, which is based on a century-old paradigm, worked sufficiently. However, in the end, it is a very energy-inefficient process’, says co-author Bert Kappen, Professor of Neural networks and machine intelligence.

The physicists at Radboud University researched whether a piece of hardware could do the same, without the need of software. They discovered that by constructing a network of cobalt atoms on black phosphorus they were able to build a material that stores and processes information in similar ways to the brain, and, even more surprisingly, adapts itself.

Self-adapting atoms

In 2018, Khajetoorians and collaborators showed that it is possible to store information in the state of a single cobalt atom. By applying a voltage to the atom, they could induce “firing”, where the atom shuttles between a value of 0 and 1 randomly, much like one neuron. They have now discovered a way to create tailored ensembles of these atoms, and found that the firing behaviour of these ensembles mimics the behaviour of a brain-like model used in artificial intelligence.

In addition to observing the behaviour of spiking neurons, they were able to create the smallest synapse known to date. Unknowingly, they observed that these ensembles had an inherent adaptive property: their synapses changed their behaviour depending on what input they “saw”. ‘When stimulating the material over a longer period of time with a certain voltage, we were very surprised to see that the synapses actually changed. The material adapted its reaction based on the external stimuli that it received. It learned by itself’, says Khajetoorians.

Exploring and developing the quantum brain

The researchers now plan to scale up the system and build a larger network of atoms, as well as dive into new “quantum” materials that can be used. Also, they need to understand why the atom network behaves as it does. ‘We are at a state where we can start to relate fundamental physics to concepts in biology, like memory and learning’, says Khajetoorians.

If we could eventually construct a real machine from this material, we would be able to build self-learning computing devices that are more energy efficient and smaller than today’s computers. Yet, only when we understand how it works – and that is still a mystery – will we be able to tune its behaviour and start developing it into a technology. It is a very exciting time.’

Here is a charming image illustrating the reasons for a quantum brain,

Courtesy: Radboud University

Here’s a link to and a citation for the paper,

An atomic Boltzmann machine capable of self-adaption by Brian Kiraly, Elze J. Knol, Werner M. J. van Weerdenburg, Hilbert J. Kappen & Alexander A. Khajetoorians. Nature Nanotechnology (2021) DOI: https://doi.org/10.1038/s41565-020-00838-4 Published: 01 February 2021

This paper is behind a paywall.

‘Greener’ lithium mining in Canada

A February 19, 2021 article by Pamela Fieber for CBC (Canadian Broadcasting Corporation) news online features news of a Calgary (Alberta) company, Summit Nanotech, and a greener way to mine lithium (Note: A link has been removed),

Amanda Hall was on top of a mountain in Tibet when inspiration struck. 

“I saw a Tibetan monk reach into his robe and pull out an iPhone,” Hall told the Calgary Eyeopener [CBC radio programme].

“If there’s an iPhone at the top of a mountain in Tibet, where isn’t there an iPhone on this planet? And then it just got me thinking about batteries and battery technology and energy and how we store that energy.”

On her return to Calgary, the accomplished geophysicist began looking into a better, greener way to mine lithium — the essential ingredient in lithium-ion batteries, which power electric cars and smartphones.

This led to her founding the company, Summit Nanotech in 2018 and developing nanotechnology, which works with materials at the molecular or atomic level to selectively filter lithium out of the wasted saltwater brine used in oil wells.

It’s completely different from the way lithium is traditionally mined.

Sarah Offin’s November 12, 2020 article for Global TV News offers insight into the technology developed by Hall’s company (Note: Links have been removed),

Since the downturn in the oil and gas industry, there have been repeated calls for Alberta to diversify its economy. The province invests hundreds of millions of dollars every year to help grow both the tech and green energy sectors, industries that could have a bright future in a province rich with talent.

Amanda Hall is a prime example of that. She was able to draw on her experience in resource extraction with Alberta’s oil and gas industry, developing green technology to be used in energy storage.

Hall developed the only female-led mining technology company in the world: Summit Nanotech Corp. Using nanotechnology, Hall and her team say they have created an improved method of lithium-ion resource extraction from produced brine water.

“We’ve come up with a much more elegant approach — I say, feminine, approach — at bringing a resource out of the ground, and then giving it to the electric vehicle sector,” Hall said.

Using sponges developed through nanoscience, Hall and her team have created technology that will allow producers to extract lithium directly from the wellhead without the need for expansive ponds and toxic chemicals. The process is expected to reduce costs and decrease chemical waste by 90 per cent.

The firm’s website touts that its process is the most “green lithium extraction in the world.”

“The sponge has lithium selective cavities in it, just the exact size of a lithium-ion. And so, as if you put a fluid in against this sponge, it will only suck up lithium, nothing else, and it holds on to it. And then when you wash it, you wash the lithium off the sponge just by changing the environment it’s in. So we don’t have to use any acids,” Hall said.

Hall and her team have spent the last two-and-a-half years in the lab perfecting their design and are now building the company’s first full-scale 12-metre tall unit. “It’s our baby, but it’s huge,” Hall said. “It’s a mini-refinery, essentially.”

That “mini-refinery” will then be sent via shipping container to the first of the company’s three pilot partners: Lithium Chile.

The other two partners are Saskatchewan-based Prairie Lithium and 3 Proton Lithium (3PL) Operating Inc. in Nevada.

For anyone interested in the business and investment aspects (there’s mention of Elon Musk in both stories) check out Fieber’s February 19, 2021 article and Offin’s November 12, 2020 article.

You can find Summit Nanotech here. I found a little more information about the company’s technology on the Lithium webpage,

denaLi 1.0
Direct Lithium Extraction
(DLE) Process

Summit Nanotech has designed an innovative new method to generate battery grade lithium compounds from brine fluids, named denaLi. This process is the most green lithium extraction technology in the world. Lithium carbonate and lithium hydroxide can be sold at market value to supply the growing demand from electric vehicle battery manufacturers. 

Interconnected modules using nanoporous membranes in a unique arrangement are synthesized with specific filtration functions. Carbon dioxide is used to initiate end product precipitation. Discrete power generation modules are selected to work together to harvest and store available geothermal, solar, wind, and hydroelectric power from the system’s environment.

Prairie Lithium, the Saskatchewan-based company mentioned in Offin’s article, co-founded a joint venture specifically dedicated to lithium extraction from brine (to begin with) in 2020 according to Jonathan Guignard in a June 3, 2020 article for Global TV news (Note: Links have been removed),

Saskatchewan will soon be home to a new lithium production project.

The Prairie-LiEP Critical Mineral (PLCM) joint venture is being undertaken by Prairie Lithium Corp. and LiEP Energy Ltd [headquarted in Calgary, Alberta].

Their two-stage pilot project will produce lithium hydroxide from some of the province’s oilfield brines.

The first stage of the project is based in Regina and is set to being in July. The second stage is set for the second half of 2021, with field operations in southern parts of the province.

“PLCM Joint Venture is excited to begin Stage 1 of the pilot operation in Saskatchewan this summer,” said Prairie president and CEO Zach Maurer and LiEP president and CEO Haafiz Hasham.

I can’t find any mention of the PLCM joint venture on the Prairie Lithium website but there is what appears to be a June 3, 2020 news release announcing the venture on the LiEP Energy website but there is no further information on that website.

On another front, Lithium Chile, which seems to be headquartered in Calgary with extensive lithium mining projects in Chile, has a brief mention of their partnership with Summit Nanotech in a December 24, 2020 posting (on the News webpage) by Steve (Cochrane; president and chief executive officer),

Lastly our partnership with Summit continues to move forward and we are very happy to be working with them. I have attached our recently negotiated LOI [letter of intent] for our JV [joint venture] pilot project in Chile. We should have the definitive agreement signed early in the new year. They plan to have their pilot unit completed and shipped by July of 2021 so a planned test is scheduled for late summer next year. This gives us the time to get back on one or more of our lithium prospects to prepare for our pilot project. They continue to see great results in the lab and hope this is the breakthrough we all want to see for an efficient cost and environmentally effective method of producing lithium from brines.

I cannot find any further mention on the Lithium Chile website about their joint venture with Summit Nanotech.

The big question is whether or not this technology can be scaled for industrial use. I wish them good luck with the effort.

All this talk about lithium extraction and other natural resource extraction brought to mind Harold Innis and his staples theory of Canadian history, culture, and economy. From the Harold Innis Wikipedia entry (Note: Links have been removed),

Harold Adams Innis FRSC (1894 – 1952) was a Canadian professor of political economy at the University of Toronto and the author of seminal works on media, communication theory, and Canadian economic history. He helped develop the staples thesis, [emphasis mine] which holds that Canada’s culture, political history, and economy have been decisively influenced by the exploitation and export of a series of “staples” such as fur, fishing, lumber, wheat, mined metals [emphasis mine], and coal. The staple thesis dominated economic history in Canada from the 1930s to 1960s, and continues to be a fundamental part of the Canadian political economic tradition.[8]

There you have it.

Fungal wearable tech and building materials

This is the first time I’ve seen wearable tech based on biological material, in this case, fungi. In diving further into this material (wordplay intended), I discovered some previous work on using fungi for building materials, which you’ll find later in this posting.

Wearable tech and more

A January 18, 2021 news item on phys.org provides some illumination on the matter,

Fungi are among the world’s oldest and most tenacious organisms. They are now showing great promise to become one of the most useful materials for producing textiles, gadgets and other construction materials. The joint research venture undertaken by the University of the West of England, Bristol, the U.K. (UWE Bristol) and collaborators from Mogu S.r.l., Italy, Istituto Italiano di Tecnologia, Torino, Italy and the Faculty of Computer Science, Multimedia and Telecommunications of the Universitat Oberta de Catalunya (UOC) has demonstrated that fungi possess incredible properties that allow them to sense and process a range of external stimuli, such as light, stretching, temperature, the presence of chemical substances and even electrical signals. [emphasis mine]

This could help pave the way for the emergence of new fungal materials with a host of interesting traits, including sustainability, durability, repairability and adaptability. Through exploring the potential of fungi as components in wearable devices, the study has verified the possibility of using these biomaterials as efficient sensors with endless possible applications.

A January 18, 2021 Universitat Oberta de Catalunya (UOC) press release (also on EurekAlert), which originated the news item, describes this vision for future wearable tech based on fungi,

Fungi to make smart wearables even smarter

People are unlikely to think of fungi as a suitable material for producing gadgets, especially smart devices such as pedometers or mobile phones. Wearable devices require sophisticated circuits that connect to sensors and have at least some computing power, which is accomplished through complex procedures and special materials. This, roughly speaking, is what makes them “smart”. The collaboration of Prof. Andrew Adamatzky and Dr. Anna Nikolaidou from UWE Bristol’s Unconventional Computing Laboratory, Antoni Gandia, Chief Technology Officer at Mogu S.r.l., Prof. Alessandro Chiolerio from Istituto Italiano di Tecnologia, Torino, Italy and Dr. Mohammad Mahdi Dehshibi, researcher with the UOC’s Scene Understanding and Artificial Intelligence Lab (SUNAI) have demonstrated that fungi can be added to the list of these materials.

Indeed, the recent study, entitled “Reactive fungal wearable” and featured in Biosystems, analyses the ability of oyster fungus Pleurotus ostreatus to sense environmental stimuli that could come, for example, from the human body. In order to test the fungus’s response capabilities as a biomaterial, the study analyses and describes its role as a biosensor with the ability to discern between chemical, mechanical and electrical stimuli.

“Fungi make up the largest, most widely distributed and oldest group of living organisms on the planet,” said Dehshibi, who added, “They grow extremely fast and bind to the substrate you combine them with”. According to the UOC researcher, fungi are even able to process information in a way that resembles computers.

“We can reprogramme a geometry and graph-theoretical structure of the mycelium networks and then use the fungi’s electrical activity to realize computing circuits,” said Dehshibi, adding that, “Fungi do not only respond to stimuli and trigger signals accordingly, but also allow us to manipulate them to carry out computational tasks, in other words, to process information”. As a result, the possibility of creating real computer components with fungal material is no longer pure science fiction. In fact, these components would be capable of capturing and reacting to external signals in a way that has never been seen before.

Why use fungi?

These fungi have less to do with diseases and other issues caused by their kin when grown indoors. What’s more, according to Dehshibi, mycelium-based products are already used commercially in construction. He said: “You can mould them into different shapes like you would with cement, but to develop a geometric space you only need between five days and two weeks. They also have a small ecological footprint. In fact, given that they feed on waste to grow, they can be considered environmentally friendly”.

The world is no stranger to so-called “fungal architectures” [emphasis mine], built using biomaterials made from fungi. Existing strategies in this field involve growing the organism into the desired shape using small modules such as bricks, blocks or sheets. These are then dried to kill off the organism, leaving behind a sustainable and odourless compound.

But this can be taken one step further, said the expert, if the mycelia are kept alive and integrated into nanoparticles and polymers to develop electronic components. He said: “This computer substrate is grown in a textile mould to give it shape and provide additional structure. Over the last decade, Professor Adamatzky has produced several prototypes of sensing and computing devices using the slime mould Physarum polycephalum, including various computational geometry processors and hybrid electronic devices.”

The upcoming stretch

Although Professor Adamatzky found that this slime mould is a convenient substrate for unconventional computing, the fact that it is continuously changing prevents the manufacture of long-living devices, and slime mould computing devices are thus confined to experimental laboratory set-ups.

However, according to Dehshibi, thanks to their development and behaviour, basidiomycetes are more readily available, less susceptible to infections, larger in size and more convenient to manipulate than slime mould. In addition, Pleurotus ostreatus, as verified in their most recent paper, can be easily experimented on outdoors, thus opening up the possibility for new applications. This makes fungi an ideal target for the creation of future living computer devices.

The UOC researcher said: “In my opinion, we still have to address two major challenges. The first consists in really implementing [fungal system] computation with a purpose; in other words, computation that makes sense. The second would be to characterize the properties of the fungal substrates via Boolean mapping, in order to uncover the true computing potential of the mycelium networks.” To word it another way, although we know that there is potential for this type of application, we still have to figure out how far this potential goes and how we can tap into it for practical purposes.

We may not have to wait too long for the answers, though. The initial prototype developed by the team, which forms part of the study, will streamline the future design and construction of buildings with unique capabilities, thanks to their fungal biomaterials. The researcher said: “This innovative approach promotes the use of a living organism as a building material that is also fashioned to compute.” When the project wraps up in December 2022, the FUNGAR project will construct a large-scale fungal building in Denmark and Italy, as well as a smaller version on UWE Bristol’s Frenchay Campus.

Dehshibi said: “To date, only small modules such as bricks and sheets have been manufactured. However, NASA [US National Aeronautics Space Administration] is also interested in the idea and is looking for ways to build bases on the Moon and Mars to send inactive spores to other planets.” To conclude, he said: “Living inside a fungus may strike you as odd, but why is it so strange to think that we could live inside something living? It would mark a very interesting ecological shift that would allow us to do away with concrete, glass and wood. Just imagine schools, offices and hospitals that continuously grow, regenerate and die; it’s the pinnacle of sustainable life.”

For the Authors of the paper, the point of fungal computers is not to replace silicon chips. Fungal reactions are too slow for that. Rather, they think humans could use mycelium growing in an ecosystem as a “large-scale environmental sensor.” Fungal networks, they reason, are monitoring a large number of data streams as part of their everyday existence. If we could plug into mycelial networks and interpret the signals, they use to process information, we could learn more about what was happening in an ecosystem.

Here’s a link to and a citation for the paper,

Reactive fungal wearable by Andrew Adamatzky, Anna Nikolaidou, Antoni Gandia, Alessandro Chiolerio, Mohammad Mahdi Dehshibi. Biosystems Volume 199, January 2021, 104304 DOI: https://doi.org/10.1016/j.biosystems.2020.104304

This paper is behind a paywall.

Fungal architecture and building materials

Here’s a video, which shows the work which inspired the fungal architecture that Dr. Dehshibi mentioned in the press release about wearable tech,

The video shows a 2014 Hy-Fi installation by The Living for MoMA (Museum of Modern Art) PS1 in New York City. Here’s more about HyFi and what it inspired from a January 15, 2021 article by Caleb Davies for the EU (European Union) Research and Innovation Magazine and republished on phys.org (Note: Links have been removed),

In the summer of 2014 a strange building began to take shape just outside MoMA PS1, a contemporary art centre in New York City. It looked like someone had started building an igloo and then got carried away, so that the ice-white bricks rose into huge towers. It was a captivating sight, but the truly impressive thing about this building was not so much its looks but the fact that it had been grown.

The installation, called Hy-Fi, was designed and created by The Living, an architectural design studio in New York. Each of the 10,000 bricks had been made by packing agricultural waste and mycelium, the fungus that makes mushrooms, into a mould and letting them grow into a solid mass.

This mushroom monument gave architectural researcher Phil Ayres an idea. “It was impressive,” said Ayres, who is based at the Centre for Information Technology and Architecture in Copenhagen, Denmark. But this project and others like it were using fungus as a component in buildings such as bricks without necessarily thinking about what new types of building we could make from fungi.

That’s why he and three colleagues have begun the FUNGAR project—to explore what kinds of new buildings we might construct out of mushrooms.

FUNGAR (Fungal Architectures) can be found here, Mogu can be found here, and The Living can be found here.

Carbon nanotubes (CNTs) in 466 colours

Caption: A color map illustrates the inherent colors of 466 types of carbon nanotubes with unique (n,m) designations based their chiral angle and diameter. Credit: Image courtesy of Kauppinen Group/Aalto University

This is, so to speak, a new angle on carbon nanotubes (CNTs). It’s also the first time I’ve seen two universities place identical news releases on EurekAlert under their individual names.

From the Dec. 14, 2020 Rice University (US) news release or the Dec. 14, 2020 Aalto University (Finland) press release on EurekAlert,

Nanomaterials researchers in Finland, the United States and China have created a color atlas for 466 unique varieties of single-walled carbon nanotubes.

The nanotube color atlas is detailed in a study in Advanced Materials about a new method to predict the specific colors of thin films made by combining any of the 466 varieties. The research was conducted by researchers from Aalto University in Finland, Rice University and Peking University in China.

“Carbon, which we see as black, can appear transparent or take on any color of the rainbow,” said Aalto physicist Esko Kauppinen, the corresponding author of the study. “The sheet appears black if light is completely absorbed by carbon nanotubes in the sheet. If less than about half of the light is absorbed in the nanotubes, the sheet looks transparent. When the atomic structure of the nanotubes causes only certain colors of light, or wavelengths, to be absorbed, the wavelengths that are not absorbed are reflected as visible colors.”

Carbon nanotubes are long, hollow carbon molecules, similar in shape to a garden hose but with sides just one atom thick and diameters about 50,000 times smaller than a human hair. The outer walls of nanotubes are made of rolled graphene. And the wrapping angle of the graphene can vary, much like the angle of a roll of holiday gift wrap paper. If the gift wrap is rolled carefully, at zero angle, the ends of the paper will align with each side of the gift wrap tube. If the paper is wound carelessly, at an angle, the paper will overhang on one end of the tube.

The atomic structure and electronic behavior of each carbon nanotube is dictated by its wrapping angle, or chirality, and its diameter. The two traits are represented in a “(n,m)” numbering system that catalogs 466 varieties of nanotubes, each with a characteristic combination of chirality and diameter. Each (n,m) type of nanotube has a characteristic color.

Kauppinen’s research group has studied carbon nanotubes and nanotube thin films for years, and it previously succeeded in mastering the fabrication of colored nanotube thin films that appeared green, brown and silver-grey.

In the new study, Kauppinen’s team examined the relationship between the spectrum of absorbed light and the visual color of various thicknesses of dry nanotube films and developed a quantitative model that can unambiguously identify the coloration mechanism for nanotube films and predict the specific colors of films that combine tubes with different inherent colors and (n,m) designations.

Rice engineer and physicist Junichiro Kono, whose lab solved the mystery of colorful armchair nanotubes in 2012, provided films made solely of (6,5) nanotubes that were used to calibrate and verify the Aalto model. Researchers from Aalto and Peking universities used the model to calculate the absorption of the Rice film and its visual color. Experiments showed that the measured color of the film corresponded quite closely to the color forecast by the model.

The Aalto model shows that the thickness of a nanotube film, as well as the color of nanotubes it contains, affects the film’s absorption of light. Aalto’s atlas of 466 colors of nanotube films comes from combining different tubes. The research showed that the thinnest and most colorful tubes affect visible light more than those with larger diameters and faded colors.

“Esko’s group did an excellent job in theoretically explaining the colors, quantitatively, which really differentiates this work from previous studies on nanotube fluorescence and coloration,” Kono said.

Since 2013, Kono’s lab has pioneered a method for making highly ordered 2D nanotube films. Kono said he had hoped to supply Kauppinen’s team with highly ordered 2D crystalline films of nanotubes of a single chirality.

“That was the original idea, but unfortunately, we did not have appropriate single-chirality aligned films at that time,” Kono said. “In the future, our collaboration plans to extend this work to study polarization-dependent colors in highly ordered 2D crystalline films.”

The experimental method the Aalto researchers used to grow nanotubes for their films was the same as in their previous studies: Nanotubes grow from carbon monoxide gas and iron catalysts in a reactor that is heated to more than 850 degrees Celsius. The growth of nanotubes with different colors and (n,m) designations is regulated with the help of carbon dioxide that is added to the reactor.

“Since the previous study, we have pondered how we might explain the emergence of the colors of the nanotubes,” said Nan Wei, an assistant research professor at Peking University who previously worked as a postdoctoral researcher at Aalto. “Of the allotropes of carbon, graphite and charcoal are black, and pure diamonds are colorless to the human eye. However, now we noticed that single-walled carbon nanotubes can take on any color: for example, red, blue, green or brown.”

Kauppinen said colored thin films of nanotubes are pliable and ductile and could be useful in colored electronics structures and in solar cells.

“The color of a screen could be modified with the help of a tactile sensor in mobile phones, other touch screens or on top of window glass, for example,” he said.

Kauppinen said the research can also provide a foundation for new kinds of environmentally friendly dyes.

Here’s a link to and a citation for the paper,

Colors of Single‐Wall Carbon Nanotubes by Nan Wei, Ying Tian, Yongping Liao, Natsumi Komatsu, Weilu Gao, Alina Lyuleeva‐Husemann, Qiang Zhang, Aqeel Hussain, Er‐Xiong Ding, Fengrui Yao, Janne Halme. Kaihui Liu, Junichiro Kono, Hua Jiang, Esko I. Kauppinen. Advanced Materials DOI: https://doi.org/10.1002/adma.202006395 First published: 14 December 2020

Thi8s paper is open access.