Category Archives: construction

Programmable living materials made with 3D printing methods and synthetic biology

There’s more than one ‘living’ material story here on this blog; it’s the plant cells that make this latest story different from the others. From a May 1, 2024 news item on phys.org, Note: A link has been removed,

Scientists are harnessing cells to make new types of materials that can grow, repair themselves and even respond to their environment. These solid “engineered living materials” are made by embedding cells in an inanimate matrix that’s formed in a desired shape. Now, researchers report in ACS Central Science that they have 3D printed a bioink containing plant cells that were then genetically modified, producing programmable materials. Applications could someday include biomanufacturing and sustainable construction.

Caption: After 24 days, the colors produced by plant cells in two different bioinks printed in this leaf-shaped engineered living material are clearly visible. Credit: Adapted from ACS Central Science 2024, DOI: 10.1021/acscentsci.4c00338

A May 1, 2024 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, explains what makes this living material different,

Recently, researchers have been developing engineered living materials, primarily relying on bacterial and fungal cells as the live component. But the unique features of plant cells have stirred enthusiasm for their use in engineered plant living materials (EPLMs). However, the plant cell-based materials created to date have had fairly simple structures and limited functionality. Ziyi Yu, Zhengao Di and colleagues wanted to change that by making intricately shaped EPLMs containing genetically engineered plant cells with customizable behaviors and capabilities.

The researchers mixed tobacco plant cells with gelatin and hydrogel microparticles that contained Agrobacterium tumefaciens, a bacterium commonly used to transfer DNA segments into plant genomes. This bioink mixture was then 3D printed on a flat plate or inside a container filled with another gel to form shapes such as grids, snowflakes, leaves and spirals. Next, the hydrogel in the printed materials was cured with blue light, hardening the structures. During the ensuing 48 hours, the bacteria in the EPLMs transferred DNA to the growing tobacco cells. The materials were then washed with antibiotics to kill the bacteria. In the following weeks, as the plant cells grew and replicated in the EPLMs, they began producing proteins dictated by the transferred DNA.

In this proof-of-concept study, the transferred DNA enabled the tobacco plant cells to produce green fluorescent proteins or betalains — red or yellow plant pigments that are valued as natural colorants and dietary supplements. By printing a leaf-shaped EPLM with two different bioinks — one that created red pigment along the veins and the other a yellow pigment in the rest of the leaf — the researchers showed that their technique could produce complex, spatially controlled and multifunctional structures. Such EPLMs, which combine the traits of living organisms with the stability and durability of non-living substances, could find use as cellular factories to churn out plant metabolites or pharmaceutical proteins, or even in sustainable construction applications, according to the researchers.

The authors acknowledge funding from National Key Research and Development Program of China, the National Natural Science Foundation of China, the Natural Science Foundation of Jiangsu Province, and the State Key Laboratory of Materials-Oriented Chemical Engineering.

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

Advancing Engineered Plant Living Materials through Tobacco BY-2 Cell Growth and Transfection within Tailored Granular Hydrogel Scaffolds by Yujie Wang, Zhengao Di, Minglang Qin, Shenming Qu, Wenbo Zhong, Lingfeng Yuan, Jing Zhang, Julian M. Hibberd, and Ziyi Yu. ACS Cent. Sci. 2024, 10, 5, 1094–1104 DOI: https://doi.org/10.1021/acscentsci.4c00338 Publication Date:May 1, 2024 Copyright © 2024 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.

This paper is open access.

I think the last three years in particular have seen an upsurge of living materials stories (on this blog, at least). This one is a favourite of mine,

If you’re curious to see more, I suggest using the search term ‘living materials’.

3D printed nanocellulose for green architectural applications

It’s not happening next week but it is a promising step forward if you’re looking for nancellulose applications. From a February 7, 2024 news item on Nanowerk, Note: A link has been removed,

For the first time, a hydrogel material made of nanocellulose and algae has been tested as an alternative, greener architectural material. The study, from Chalmers University of Technology in Sweden and the Wallenberg Wood Science Center, shows how the abundant sustainable material can be 3D printed into a wide array of architectural components, using much less energy than conventional construction methods.

Caption: 3D printed nanocellulose upscaled for green architectural applications. Credit: Chalmers University of Technology | Emma Fry

A February 6, 2024 Chalmers University of Technology press release (also on EurekAlert but published February 7, 2024), which originated the news item,

The construction industry today consumes 50 percent of the world’s fossil resources, generates 40 percent of global waste and causes 39 percent of global carbon dioxide emissions. There is a growing line of research into biomaterials and their applications, in order to transition to a greener future in line with, for example, the European Green Deal.

Nanocellulose is not a new biomaterial, and its properties as a hydrogel are known within the field of biomedicine, where it can be 3D printed into scaffolds for tissue and cell growth, due to its biocompatibility and wetness. But it has never been dried and used as an architectural material before.

“For the first time we have explored an architectural application of nanocellulose hydrogel. Specifically, we provided the so far missing knowledge on its design-related features, and showcased, with the help of our samples and prototypes, the tuneability of these features through custom digital design and robotic 3D printing,” says Malgorzata Zboinska, lead author of the study from Chalmers University of Technology.

The team used nanocellulose fibres and water, with the addition of an algae-based material called alginate. The alginate allowed the researchers to produce a 3D printable material, since the alginate added an extra flexibility to the material when it dried.

Cellulose is coined as the most abundant eco-friendly alternative to plastic, as it is one of the byproducts of the world’s largest industries. “The nanocellulose used in this study can be acquired from forestry, agriculture, paper mills and straw residues from agriculture. It is a very abundant material in that sense,” says Malgorzata Zboinska.

3D printing and nanocellulose/ A resource efficient technique

The architectural industry is today surrounded by access to digital technologies which allows for a wider range of new techniques to be used, but there is a gap in the knowledge of how these techniques can be applied. According to the European Green Deal, as of 2030, buildings in Europe must be more resource-efficient, and this can be achieved through elevated reuse and recycling of materials, such as with nanocellulose, an upcycled, byproduct from industry. At the same time as buildings are to become more circular, cutting-edge digital techniques are highlighted as important leverages for achieving these goals.

“3D printing is a very resource efficient technique. It allows us to make products without other things such as dies and casting forms, so there is less waste material. It is also very energy efficient. The robotic 3D printing system we employ does not use heat, just air pressure. This saves a lot of energy as we are only working at room temperature,” says Malgorzata Zboinska.

The energy efficient process relies on the shear thinning properties of the nanocellulose hydrogel. When you apply pressure it liquifies allowing it to be 3D printed, but when you take away the pressure it maintains its shape. This allows the researchers to work without the energy intensive processes that are commonplace in the construction industry.

Malgorzata Zboinska and her team designed many different toolpaths to be used in the robotic 3D printing process to see how the nanocellulose hydrogel would behave when it dried in different shapes and patterns. These dried shapes could then be applied as a basis to design a wide array of architectural standalone components, such as lightweight room dividers, blinds, and wall panel systems. They could also form the basis for coatings of existing building components, such as tiles to clad walls, acoustic elements for damping sound, and combined with other materials to clad skeleton walls.

The future of greener building materials

“Traditional building materials are designed to last for hundreds of years. Usually, they have predictable behaviours and homogenous properties. We have concrete, glass and all kinds of hard materials that endure and we know how they will age over time. Contrary to this, biobased materials contain organic matter, that is from the outset designed to biodegrade and cycle back into nature. We, therefore, need to acquire completely new knowledge on how we could apply them in architecture, and how we could embrace their shorter life cycle loops and heterogenous behaviour patterns, resembling more those found in nature rather than in an artificial and fully controlled environment. Design researchers and architects are now intensely searching for ways of designing products made from these materials, both for function and for aesthetics,” says Malgorzata Zboinska.

This study provides the first steps to demonstrate the upscaling potentials of ambient-dried, 3D-printed nanocellulose membrane constructs, as well as a new understanding of the relationship between the design of the material’s deposition pathways via 3D printing, and the dimensional, textural, and geometric effects in the final constructs. This knowledge is a necessary stepping stone that will allow Malgorzata Zboinska and her team to develop, through further research, applications of nanocellulose in architectural products that need to meet specific functional and aesthetic user requirements.  

“The yet not fully known properties of novel biobased materials prompt architectural researchers to establish alternative approaches to designing these new products, not only in terms of the functional qualities, but also the acceptance from the users. The aesthetics of biobased materials are an important part of this. If we are to propose these biobased materials to society and people, we need to work with the design as well. This becomes a very strong element for the acceptance of these materials. If people do not accept them, we will not reach the goals of a circular economy and sustainable built environment”.

More about the research:

The research is presented in a paper: “Robotically 3D printed architectural membranes from ambient dried cellulose nanofibril-alginate hydrogel”, published in the journal Materials and Design.

The researchers involved in the study are Malgorzata A. Zboinska, Sanna Sämfors and Paul Gatenholm. The researchers were active at Chalmers University of Technology and the Wallenberg Wood Science Center, both in Sweden, at the time of the study.

This work was supported by Adlerbertska Research Foundation and Chalmers University of Technology’s Area of Advance Materials Science. The Knut and Alice Wallenberg Foundation is gratefully acknowledged for funding the Wallenberg Wood Science Center. The authors would also like to recognise the contribution of Karl Åhlund, who assisted in the robotic extrusion system development.

Fact box – previous research:

Printing with nanocellulose was first developed at Chalmers University of Technology within the Wallenberg Wood Science Center in 2015. This is the first time this technology is being scaled up towards applications in buildings.

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

Robotically 3D printed architectural membranes from ambient dried cellulose nanofibril-alginate hydrogel by Malgorzata A. Zboinska, Sanna Sämfors, Paul Gatenholm. Materials & Design Volume 236, December 2023, 112472 DOI: https://doi.org/10.1016/j.matdes.2023.112472

This paper appears to be open access.

For the curious, here’s The European Green Deal.

The art and science of architecture that is ‘living-like’

Biology in the service of architecture, from a June 21, 2023 news item on phys.org, Note: Links have been removed,

“This technology is not alive,” says Laia Mogas-Soldevila. “It is living-like.”

The distinction is an important one for the assistant professor at the Stuart Weitzman School of Design [University of Pennsylvania], for reasons both scientific and artistic. With a doctorate in biomedical engineering, several degrees in architecture, and a devotion to sustainable design, Mogas-Soldevila brings biology to everyday life, creating materials for a future built halfway between nature and artifice.

A June 21, 2023 University of Pennsylvania news release (from a Penn Engineering Today blog posting by Devorah Fischler; also on EurekAlert), which originated the news item, provides more details, Note: Links have been removed,

The architectural technology she describes is unassuming at first look: A freeze-dried pellet, small enough to get lost in your pocket. But this tiny lump of matter, the result of more than a year’s collaboration between designers, engineers and biologists, is a biomaterial that contains a “living-like” system.

When touched by water, the pellet activates and expresses a glowing protein, its fluorescence demonstrating that life and art can harmonize into a third and very different thing, as ready to please as to protect. Woven into lattices made of flexible natural materials promoting air and moisture flow, the pellets form striking interior design elements that could one day keep us healthy.

“We envision them as sensors,” explains Mogas-Soldevila. “They may detect pathogens, such as bacteria or viruses, or alert people to toxins inside their home. The pellets are designed to interact with air. With development, they could monitor or even clean it.”

For now, they glow, a triumphant first stop on the team’s roadmap to the future. The fluorescence establishes that the lab’s biomaterial manufacturing process is compatible with the leading-edge cell-free engineering that gives the pellets their life-like properties.

A rapidly expanding technology, cell-free protein expression systems allow researchers to manufacture proteins without the use of living cells.

Gabrielle Ho, Ph.D. candidate in the Department of Bioengineering and co-leader of the project, explains how the team’s design work came to be cell-free, a technique rarely explored outside of lab study or medical applications.

“Typically, we’d use living E. coli cells to make a protein,” says Ho. “E. coli is a biological workhorse, accessible and very productive. We’d introduce DNA to the cell to encourage expression of specific proteins. But this traditional method was not an option for this project. You can’t have engineered E. coli hanging on your walls.”

Cell-free systems contain all the components a living cell requires to manufacture protein —energy, enzymes and amino acids — and not much else. These systems are therefore not alive. They do not replicate, and neither can they cause infection. They are “living-like,” designed to take in DNA and push out protein in ways that previously were only possible using living cells.

“One of the nicest things about these materials not being alive,” says Mogas-Soldevila, “is that we don’t need to worry about keeping them that way.”

Unlike living cells, cell-free materials don’t need a wet environment or constant monitoring in a lab. The team’s research has established a process for making these dry pellets that preserves bioactivity throughout manufacturing, storage and use.

Bioactive, expressive and programmable, this technology is designed to capitalize on the unique properties of organic materials.

Mogas-Soldevila, whose lab focuses exclusively on biodegradable architecture, understands the value of biomaterials as both environmentally responsible and aesthetically rich.

“Architects are coming to the realization that conventional materials — concrete, steel, glass, ceramic, etc. — are environmentally damaging and they are becoming more and more interested in alternatives to replace at least some of them. Because we use so much, even being able to replace a small percentage would result in a significant reduction in waste and pollution.”

Her lab’s signature materials — biopolymers made from shrimp shells, wood pulp, sand and soil, silk cocoons, and algae gums — lend qualities over and above their sustainable advantages.

“My obsession is diagnostic, but my passion is playfulness,” says Mogas-Soldevila. “Biomaterials are the only materials that can encapsulate this double function observed in nature.”

This multivalent approach benefited from the help of Penn Engineering’s George H. Stephenson Foundation Educational Laboratory & Bio-MakerSpace, and the support of its director, Sevile Mannickarottu. In addition to contributing essential equipment and research infrastructure to the team, Mannickarottu was instrumental in enabling the interdisciplinary relationships that led the team to success, introducing Ho to the DumoLab Research team collaborators. These include Mogas-Soldevila, Camila Irabien, a Penn Biology major who provided crucial contributions to experimental work, and Fulbright design fellow Vlasta Kubušová, who co-led the project during her time at Penn and who will continue fueling the project’s next steps.

The cell-free manufacturing and design research required unique dialogues between science and art, categories that Ho believed to be entirely separate before embarking on this project.

“I learned so much from the approach the designers brought to the lab,” says Ho. “Usually, in science, we have a specific problem or hypothesis that we systematically work towards.”

But in this collaboration, things were different. Open-ended. The team sought a living-like platform that does sensing and tells people about interactive matter. They needed to explore, step by step, how to get there.

“Design is only limited by imagination. We sought a technology that could help build towards a vision, and that turned out to be cell-free” says Ho.

“For my part,” says Mogas-Soldevila, “it was inspiring to witness the rigor and attention to constraints that bioengineering brings.”

The constraints were many — machine constraints, biological constraints, financial constraints and space constraints.

“But as we kept these restrictions in play,” she continues, “we asked our most pressing creative questions. Can materials warn us of invisible threats? How will humans react to these bioactive sites? Will they be beautiful? Will they be weird? Most importantly, will they enable a new aesthetic relationship with the potential of bio-based and bioactive matter?”

Down the line, the cell-free pellets and biopolymer lattices could drape protectively over our interior lives, caring for our mental and physical health. For now, research is ongoing, the poetry of design energized by constraint, the constraint of engineering energized by poetry. [emphases mine]

The “poetry of design” and “engineering energized by poetry,” eh? (I have a few comments about science, in my September 11, 2023 posting; scroll down to the ‘Poetry and physics’ subhead.)

Back on topic, here’s a link to and a citation for the paper,

Multiscale design of cell-free biologically active architectural structures by G. Ho, V. Kubušová, C. Irabien, V. Li, A. Weinstein, Sh. Chawla, D. Yeung, A. Mershin, K. Zolotovsky, L. Mogas-Soldevila. Front. Bioeng. Biotechnol., 28 March 2023 Volume 11 – 2023 DOI: https://doi.org/10.3389/fbioe.2023.1125156

This paper appears to be open access.

Building materials made with knitted molds and the root network of fungi

Caption: A 1.8m high, 2m diameter freestanding structure [mycelium vault], made of the BioKnit mycocrete using knitted formwork. Two people are sitting inside it. Credit: Image courtesy of the Hub for Biotechnology in the Built Environment.

The molds for the framework were knitted and filled with ‘mycocrete’ according to a July 14, 2023 Frontiers (Pub.) press release by Angharad Brewer Gillham (also on EurekAlert and published July 17, 2023 on the Newcastle University website),

Scientists hoping to reduce the environmental impact of the construction industry have developed a way to grow building materials using knitted molds and the root network of fungi. Although researchers have experimented with similar composites before, the shape and growth constraints of the organic material have made it hard to develop diverse applications that fulfil its potential. Using the knitted molds as a flexible framework or ‘formwork’, the scientists created a composite called ‘mycocrete’ which is stronger and more versatile in terms of shape and form, allowing the scientists to grow lightweight and relatively eco-friendly construction materials.

“Our ambition is to transform the look, feel and wellbeing of architectural spaces using mycelium in combination with biobased materials such as wool, sawdust and cellulose,” said Dr Jane Scott of Newcastle University [UK], corresponding author of the paper in Frontiers in Bioengineering and Biotechnology. The research was carried out by a team of designers, engineers, and scientists in the Living Textiles Research Group, part of the Hub for Biotechnology in the Built Environment at Newcastle University, which is funded by Research England.

Root networks

To make composites using mycelium, part of the root network of fungi, scientists mix mycelium spores with grains they can feed on and material that they can grow on. This mixture is packed into a mold and placed in a dark, humid, and warm environment so that the mycelium can grow, binding the substrate tightly together. Once it’s reached the right density, but before it starts to produce the fruiting bodies we call mushrooms, it is dried out. This process could provide a cheap, sustainable replacement for foam, timber, and plastic. But mycelium needs oxygen to grow, which constrains the size and shape of conventional rigid molds and limits current applications.

Knitted textiles offer a possible solution: oxygen-permeable molds that could change from flexible to stiff with the growth of the mycelium. But textiles can be too yielding, and it is difficult to pack the molds consistently. Scott and her colleagues set out to design a mycelium mixture and a production system that could exploit the potential of knitted forms.

“Knitting is an incredibly versatile 3D manufacturing system,” said Scott. “It is lightweight, flexible, and formable. The major advantage of knitting technology compared to other textile processes is the ability to knit 3D structures and forms with no seams and no waste.”

Samples of conventional mycelium composite were prepared by the scientists as controls, and grown alongside samples of mycocrete, which also contained paper powder, paper fiber clumps, water, glycerin, and xanthan gum. This paste was designed to be delivered into the knitted formwork with an injection gun to improve packing consistency: the paste needed to be liquid enough for the delivery system, but not so liquid that it failed to hold its shape.

Tubes for their planned test structure were knitted from merino yarn, sterilized, and fixed to a rigid structure while they were filled with the paste, so that changes in tension of the fabric would not affect the performance of the mycocrete.

Building the future

Once dried, samples were subjected to strength tests in tension, compression and flexion. The mycocrete samples proved to be stronger than the conventional mycelium composite samples and outperformed mycelium composites grown without knitted formwork. In addition, the porous knitted fabric of the formwork provided better oxygen availability, and the samples grown in it shrank less than most mycelium composite materials do when they are dried, suggesting more predictable and consistent manufacturing results could be achieved.

The team were also able to build a larger proof-of-concept prototype structure called BioKnit – a complex freestanding dome constructed in a single piece without joins that could prove to be weak points, thanks to the flexible knitted form.

“The mechanical performance of the mycocrete used in combination with permanent knitted formwork is a significant result, and a step towards the use of mycelium and textile biohybrids within construction,” said Scott. “In this paper we have specified particular yarns, substrates, and mycelium necessary to achieve a specific goal. However, there is extensive opportunity to adapt this formulation for different applications. Biofabricated architecture may require new machine technology to move textiles into the construction sector.”

The mycelium vault (also pictured above) is a freestanding structure,

Caption: A 1.8m high, 2m diameter freestanding structure made of the BioKnit mycocrete using knitted formwork. Credit: Courtesy of the Hub for Biotechnology in the Built Environment.

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

BioKnit: development of mycellium paste for use with permanent textile formwork by Romy Kaiser, Ben Bridgens, Elise Elsacker, Jane Scott. Front. Bioeng. Biotechnol., 14 July 2023 Volume 11 – 2023 DOI: https://doi.org/10.3389/fbioe.2023.1229693

This paper appears to be open access.

Enabling a transparent wood battery that stores heat and regulates indoor temperature with lemons and coconuts

i’ve had transparent wood stories here before but this time it was the lemons and coconuts which captured my attention.

Peter Olsén and Céline Montanari, researchers in the Department of Biocomposites at KTH Royal Institute of Technology in Stockholm, say the new wood composite uses components of lemon and coconuts to both heat and cool homes. (Photo: David Callahan) Courtesy: KTH Royal Institute of Technology

From a March 30, 2023 news item on Nanowerk,

A building material that combines coconuts, lemons and modified wood could one day be enough to heat and cool your home. The three renewable sources provide the key components of a wood composite thermal battery, which was developed by researchers at KTH Royal Institute of Technology in Stockholm.

Researchers reported the development in the scientific journal, Small (“Sustainable Thermal Energy Batteries from Fully Bio-Based Transparent Wood”). Peter Olsén, researcher in the Department of Biocomposites at KTH, says the material is capable of storing both heat and cold. If used in housing construction, the researchers say that 100 kilos of the material can save about 2.5 kWh per day in heating or cooling—given an ambient temperature of 24 °C.

KTH researcher Céline Montanari says that besides sunlight, any heat source can charge the battery. “The key is that the temperature fluctuates around the transition temperature, 24 °C, which can of course be tailored depending on the application and location,” she says.

A March 30, 2023 KTH Royal Institute of Technology press release, which originated the news item, describes the roles that lemons and coconuts play,

The process starts with removing lignin from wood, which creates open pores in the wood cells walls, and removes color. Later the wood structure is filled with a citrus-based molecule—limonene acrylate—and coconut based molecule. Limonene acrylate transforms into a bio-based polymer when heated, restoring the wood’s strength and allowing light to permeate. When this happens the coconut molecule are trapped within the material, enabling the storage and release of energy.

“The elegance is that the coconut molecules can transition from a solid-to-liquid which absorbs energy; or from liquid-to-solid which releases energy, in much the same way that water freezes and melts,” Montanari says. But in the transparent wood, that transition happens at a more comfortable 24C

“Through this transition, we can heat or cool our surroundings, whichever is needed,” Olsén says

Olsén says that potential uses include exterior and interior building material for both transparency and energy saving – in exteriors and interiors. The first application of the product would be for interior spaces to regulate temperatures around the 24C mark to cool and to heat. More study is needed to develop it for exterior use.

And it’s not just for homes or buildings. “Why not as a future material in greenhouses?” he says. “When the sun shines, the wood becomes transparent and stores more energy, while at night it becomes cloudy and releases the heat stored during the day. That would help reduce energy consumption for heating and at the same time provide improved growth.”

A close-up look at the material produced in the study. Courtesy: KTH Royal Institute of Technology

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

Sustainable Thermal Energy Batteries from Fully Bio-Based Transparent Wood by Céline Montanari, Hui Chen, Matilda Lidfeldt, Josefin Gunnarsson, Peter Olsén, Lars A. Berglund. Small Online Version of Record before inclusion in an issue 2301262 DOI: https://doi.org/10.1002/smll.202301262 First published online: 27 March 2023

This paper is open access.

Answer to why Roman concrete was so durable

Roman concrete lasts for millenia while our ‘modern’ concrete doesn’t and that’s what makes the Roman stuff so fascinating. There’s a very good January 6, 2023 Massachusetts Institute of Technology (MIT) news release (also on EurekAlert) which may provide an answer the mystery of the this material’s longevity,

The ancient Romans were masters of engineering, constructing vast networks of roads, aqueducts, ports, and massive buildings, whose remains have survived for two millennia. Many of these structures were built with concrete: Rome’s famed Pantheon, which has the world’s largest unreinforced concrete dome and was dedicated in A.D. 128, is still intact, and some ancient Roman aqueducts still deliver water to Rome today. Meanwhile, many modern concrete structures have crumbled after a few decades.

Researchers have spent decades trying to figure out the secret of this ultradurable ancient construction material, particularly in structures that endured especially harsh conditions, such as docks, sewers, and seawalls, or those constructed in seismically active locations.

Now, a team of investigators from MIT, Harvard University, and laboratories in Italy and Switzerland, has made progress in this field, discovering ancient concrete-manufacturing strategies that incorporated several key self-healing functionalities. The findings are published in the journal Science Advances, in a paper by MIT professor of civil and environmental engineering Admir Masic, former doctoral student Linda Seymour, and four others.

For many years, researchers have assumed that the key to the ancient concrete’s durability was based on one ingredient: pozzolanic material such as volcanic ash from the area of Pozzuoli, on the Bay of Naples. [emphasis mine] This specific kind of ash was even shipped all across the vast Roman empire to be used in construction, and was described as a key ingredient for concrete in accounts by architects and historians at the time.

Under closer examination, these ancient samples also contain small, distinctive, millimeter-scale bright white mineral features, which have been long recognized as a ubiquitous component of Roman concretes. These white chunks, often referred to as “lime clasts,” originate from lime, another key component of the ancient concrete mix. “Ever since I first began working with ancient Roman concrete, I’ve always been fascinated by these features,” says Masic. “These are not found in modern concrete formulations, so why are they present in these ancient materials?”

Previously disregarded as merely evidence of sloppy mixing practices, or poor-quality raw materials, the new study suggests that these tiny lime clasts gave the concrete a previously unrecognized self-healing capability. [emphasis mine] “The idea that the presence of these lime clasts was simply attributed to low quality control always bothered me,” says Masic. “If the Romans put so much effort into making an outstanding construction material, following all of the detailed recipes that had been optimized over the course of many centuries, why would they put so little effort into ensuring the production of a well-mixed final product? There has to be more to this story.”

Upon further characterization of these lime clasts, using high-resolution multiscale imaging and chemical mapping techniques pioneered in Masic’s research lab, the researchers gained new insights into the potential functionality of these lime clasts.

Historically, it had been assumed that when lime was incorporated into Roman concrete, it was first combined with water to form a highly reactive paste-like material, in a process known as slaking. But this process alone could not account for the presence of the lime clasts. Masic wondered: “Was it possible that the Romans might have actually directly used lime in its more reactive form, known as quicklime?”

Studying samples of this ancient concrete, he and his team determined that the white inclusions were, indeed, made out of various forms of calcium carbonate. And spectroscopic examination provided clues that these had been formed at extreme temperatures, as would be expected from the exothermic reaction produced by using quicklime instead of, or in addition to, the slaked lime in the mixture. Hot mixing, the team has now concluded, was actually the key to the super-durable nature.

“The benefits of hot mixing are twofold,” Masic says. “First, when the overall concrete is heated to high temperatures, it allows chemistries that are not possible if you only used slaked lime, producing high-temperature-associated compounds that would not otherwise form. Second, this increased temperature significantly reduces curing and setting times since all the reactions are accelerated, allowing for much faster construction.”

During the hot mixing process, the lime clasts develop a characteristically brittle nanoparticulate architecture, creating an easily fractured and reactive calcium source, which, as the team proposed, could provide a critical self-healing functionality. As soon as tiny cracks start to form within the concrete, they can preferentially travel through the high-surface-area lime clasts. This material can then react with water, creating a calcium-saturated solution, which can recrystallize as calcium carbonate and quickly fill the crack, or react with pozzolanic materials to further strengthen the composite material. These reactions take place spontaneously and therefore automatically heal the cracks before they spread. Previous support for this hypothesis was found through the examination of other Roman concrete samples that exhibited calcite-filled cracks.

To prove that this was indeed the mechanism responsible for the durability of the Roman concrete, the team produced samples of hot-mixed concrete that incorporated both ancient and modern formulations, deliberately cracked them, and then ran water through the cracks. Sure enough: Within two weeks the cracks had completely healed and the water could no longer flow. An identical chunk of concrete made without quicklime never healed, and the water just kept flowing through the sample. As a result of these successful tests, the team is working to commercialize this modified cement material.

“It’s exciting to think about how these more durable concrete formulations could expand not only the service life of these materials, but also how it could improve the durability of 3D-printed concrete formulations,” says Masic.

Through the extended functional lifespan and the development of lighter-weight concrete forms, he hopes that these efforts could help reduce the environmental impact of cement production, which currently accounts for about 8 percent of global greenhouse gas emissions. Along with other new formulations, such as concrete that can actually absorb carbon dioxide from the air, another current research focus of the Masic lab, these improvements could help to reduce concrete’s global climate impact.

The research team included Janille Maragh at MIT, Paolo Sabatini at DMAT in Italy, Michel Di Tommaso at the Instituto Meccanica dei Materiali, in Switzerland, and James Weaver at the Wyss Institute for Biologically Inspired Engineering at Harvard University. The work was carried out with the assistance of the archeological museum of Priverno, Italy.

I remember the excitement over volcanic ash (it’s mentioned in my June 3, 2016 posting titled: “Making better concrete by looking to nature for inspiration” and my February 17, 2021 posting “Nuclear power plants take a cue from Roman concrete“). As for something being ignored as unimportant or being a result poor practice when it’s not, that’s one of my favourite kinds of science story.

For the really curious, Jennifer Ouellette’s January 6, 2023 article (Ancient Roman concrete could self-heal thanks to “hot mixing” with quicklime) for Ars Technica provides a little more detail.

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

Hot mixing: Mechanistic insights into the durability of ancient Roman concrete by Linda M. Seymour, Janille Maragh, Paolo Sabatini, Michel Di Tommaso, James C. Weaver, and Admir Masic. Science Advances 6 Jan 2023 Vol 9, Issue 1 DOI: 10.1126/sciadv.add1602

This paper is open access.

One last note, DMAT is listed as Paolo Sabatini’s home institution. It is a company for which Sabatini is a co-founder and CEO (chief executive officer). DMAT has this on its About page, “Our mission is to develop breakthrough innovations in construction materials at a global scale. DMAT is at the helm of concrete’s innovation.”

Stifle the noise with seaweed

The claim that most spaces are now designed with sound-absorption in mind seems a little overblown to me but judge for yourself, from a July 14, 2022 news item on phys.org,

From airplanes to apartments, most spaces are now designed with sound-absorbing materials that help dampen the droning, echoing and murmuring sounds of everyday life. But most of the acoustic materials that can cancel out human voices, traffic and music are made from plastic foams that aren’t easily recycled or degraded. Now, researchers reporting in ACS Sustainable Chemistry & Engineering have created a biodegradable seaweed-derived film that effectively absorbs sounds in this range.

A July 14, 2022 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, describes the work in more detail,

Controlling and optimizing the way sound moves throughout a room is key to creating functional spaces. Foam acoustic panels are a common solution, and they come in a variety of materials and thicknesses tailored to specific sound requirements. Most of these foams, however, are made from polyurethane and other polymers that are derived from crude oil or shale gas. To avoid petrochemicals, researchers have explored more renewably sourced and biodegradable sound-absorbing alternatives. But many current options are made from plant fibers that don’t effectively dampen noises in the most useful range of sound frequencies, or they are too thick or unwieldy to fabricate. So, Chindam Chandraprakash and colleagues wanted to develop a plant-derived, biodegradable material that would be simple to manufacture and that could absorb a range of sounds.

The team created thin films of agar, a jelly-like material that comes from seaweed, along with other plant-derived additives and varied both the thickness and porosity of the films. After running the materials through a battery of tests, the researchers measured how well the films dampened sound across a range of frequencies — from a bass hum to a shrill whine. To do this, the team created a sound tube in which a speaker is placed at one end, and the test film is fitted over the other end. Microphones in the middle of the tube measured the amount of sound emitted by the speaker and the amount of sound reflected off the film. These experiments showed that porous films made with the highest concentrations of agar had the greatest sound-absorbing qualities and performed similarly to traditional acoustic foams. The researchers plan to explore ways to modify the agar films to give them other desirable properties, such as flame resistance, and will explore other biologically derived film materials.

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

Agar-Based Composite Films as Effective Biodegradable Sound Absorbers by Surendra Kumar, Kousar Jahan, Abhishek Verma, Manan Agarwal, and C. Chandraprakash. ACS Sustainable Chem. Eng. 2022, 10, 26, 8242–8253 DOI: https://doi.org/10.1021/acssuschemeng.2c00168 Publication Date: June 23, 2022 Copyright © 2022 American Chemical Society

This paper is behind a paywall.

Mad, bad, and dangerous to know? Artificial Intelligence at the Vancouver (Canada) Art Gallery (1 of 2): The Objects

To my imaginary AI friend

Dear friend,

I thought you might be amused by these Roomba-like* paintbots at the Vancouver Art Gallery’s (VAG) latest exhibition, “The Imitation Game: Visual Culture in the Age of Artificial Intelligence” (March 5, 2022 – October 23, 2022).

Sougwen Chung, Omnia per Omnia, 2018, video (excerpt), Courtesy of the Artist

*A Roomba is a robot vacuum cleaner produced and sold by iRobot.

As far as I know, this is the Vancouver Art Gallery’s first art/science or art/technology exhibit and it is an alternately fascinating, exciting, and frustrating take on artificial intelligence and its impact on the visual arts. Curated by Bruce Grenville, VAG Senior Curator, and Glenn Entis, Guest Curator, the show features 20 ‘objects’ designed to both introduce viewers to the ‘imitation game’ and to challenge them. From the VAG Imitation Game webpage,

The Imitation Game surveys the extraordinary uses (and abuses) of artificial intelligence (AI) in the production of modern and contemporary visual culture around the world. The exhibition follows a chronological narrative that first examines the development of artificial intelligence, from the 1950s to the present [emphasis mine], through a precise historical lens. Building on this foundation, it emphasizes the explosive growth of AI across disciplines, including animation, architecture, art, fashion, graphic design, urban design and video games, over the past decade. Revolving around the important roles of machine learning and computer vision in AI research and experimentation, The Imitation Game reveals the complex nature of this new tool and demonstrates its importance for cultural production.

And now …

As you’ve probably guessed, my friend, you’ll find a combination of both background information and commentary on the show.

I’ve initially focused on two people (a scientist and a mathematician) who were seminal thinkers about machines, intelligence, creativity, and humanity. I’ve also provided some information about the curators, which hopefully gives you some insight into the show.

As for the show itself, you’ll find a few of the ‘objects’ highlighted with one of them being investigated at more length. The curators devoted some of the show to ethical and social justice issues, accordingly, the Vancouver Art Gallery hosted the University of British Columbia’s “Speculative Futures: Artificial Intelligence Symposium” on April 7, 2022,

Presented in conjunction with the exhibition The Imitation Game: Visual Culture in the Age of Artificial Intelligence, the Speculative Futures Symposium examines artificial intelligence and the specific uses of technology in its multifarious dimensions. Across four different panel conversations, leading thinkers of today will explore the ethical implications of technology and discuss how they are working to address these issues in cultural production.”

So, you’ll find more on these topics here too.

And for anyone else reading this (not you, my friend who is ‘strong’ AI and not similar to the ‘weak’ AI found in this show), there is a description of ‘weak’ and ‘strong’ AI on the avtsim.com/weak-ai-strong-ai webpage, Note: A link has been removed,

There are two types of AI: weak AI and strong AI.

Weak, sometimes called narrow, AI is less intelligent as it cannot work without human interaction and focuses on a more narrow, specific, or niched purpose. …

Strong AI on the other hand is in fact comparable to the fictitious AIs we see in media like the terminator. The theoretical Strong AI would be equivalent or greater to human intelligence.

….

My dear friend, I hope you will enjoy.

The Imitation Game and ‘mad, bad, and dangerous to know’

In some circles, it’s better known as ‘The Turing Test;” the Vancouver Art Gallery’s ‘Imitation Game’ hosts a copy of Alan Turing’s foundational paper for establishing whether artificial intelligence is possible (I thought this was pretty exciting).

Here’s more from The Turing Test essay by Graham Oppy and David Dowe for the Stanford Encyclopedia of Philosophy,

The phrase “The Turing Test” is most properly used to refer to a proposal made by Turing (1950) as a way of dealing with the question whether machines can think. According to Turing, the question whether machines can think is itself “too meaningless” to deserve discussion (442). However, if we consider the more precise—and somehow related—question whether a digital computer can do well in a certain kind of game that Turing describes (“The Imitation Game”), then—at least in Turing’s eyes—we do have a question that admits of precise discussion. Moreover, as we shall see, Turing himself thought that it would not be too long before we did have digital computers that could “do well” in the Imitation Game.

The phrase “The Turing Test” is sometimes used more generally to refer to some kinds of behavioural tests for the presence of mind, or thought, or intelligence in putatively minded entities. …

Next to the display holding Turing’s paper, is another display with an excerpt of an explanation from Turing about how he believed Ada Lovelace would have responded to the idea that machines could think based on a copy of some of her writing (also on display). She proposed that creativity, not thinking, is what set people apart from machines. (See the April 17, 2020 article “Thinking Machines? Has the Lovelace Test Been Passed?’ on mindmatters.ai.)

It’s like a dialogue between two seminal thinkers who lived about 100 years apart; Lovelace, born in 1815 and dead in 1852, and Turing, born in 1912 and dead in 1954. Both have fascinating back stories (more about those later) and both played roles in how computers and artificial intelligence are viewed.

Adding some interest to this walk down memory lane is a 3rd display, an illustration of the ‘Mechanical Turk‘, a chess playing machine that made the rounds in Europe from 1770 until it was destroyed in 1854. A hoax that fooled people for quite a while it is a reminder that we’ve been interested in intelligent machines for centuries. (Friend, Turing and Lovelace and the Mechanical Turk are found in Pod 1.)

Back story: Turing and the apple

Turing is credited with being instrumental in breaking the German ENIGMA code during World War II and helping to end the war. I find it odd that he ended up at the University of Manchester in the post-war years. One would expect him to have been at Oxford or Cambridge. At any rate, he died in 1954 of cyanide poisoning two years after he was arrested for being homosexual and convicted of indecency. Given the choice of incarceration or chemical castration, he chose the latter. There is, to this day, debate about whether or not it was suicide. Here’s how his death is described in this Wikipedia entry (Note: Links have been removed),

On 8 June 1954, at his house at 43 Adlington Road, Wilmslow,[150] Turing’s housekeeper found him dead. He had died the previous day at the age of 41. Cyanide poisoning was established as the cause of death.[151] When his body was discovered, an apple lay half-eaten beside his bed, and although the apple was not tested for cyanide,[152] it was speculated that this was the means by which Turing had consumed a fatal dose. An inquest determined that he had committed suicide. Andrew Hodges and another biographer, David Leavitt, have both speculated that Turing was re-enacting a scene from the Walt Disney film Snow White and the Seven Dwarfs (1937), his favourite fairy tale. Both men noted that (in Leavitt’s words) he took “an especially keen pleasure in the scene where the Wicked Queen immerses her apple in the poisonous brew”.[153] Turing’s remains were cremated at Woking Crematorium on 12 June 1954,[154] and his ashes were scattered in the gardens of the crematorium, just as his father’s had been.[155]

Philosopher Jack Copeland has questioned various aspects of the coroner’s historical verdict. He suggested an alternative explanation for the cause of Turing’s death: the accidental inhalation of cyanide fumes from an apparatus used to electroplate gold onto spoons. The potassium cyanide was used to dissolve the gold. Turing had such an apparatus set up in his tiny spare room. Copeland noted that the autopsy findings were more consistent with inhalation than with ingestion of the poison. Turing also habitually ate an apple before going to bed, and it was not unusual for the apple to be discarded half-eaten.[156] Furthermore, Turing had reportedly borne his legal setbacks and hormone treatment (which had been discontinued a year previously) “with good humour” and had shown no sign of despondency prior to his death. He even set down a list of tasks that he intended to complete upon returning to his office after the holiday weekend.[156] Turing’s mother believed that the ingestion was accidental, resulting from her son’s careless storage of laboratory chemicals.[157] Biographer Andrew Hodges theorised that Turing arranged the delivery of the equipment to deliberately allow his mother plausible deniability with regard to any suicide claims.[158]

The US Central Intelligence Agency (CIA) also has an entry for Alan Turing dated April 10, 2015 it’s titled, The Enigma of Alan Turing.

Back story: Ada Byron Lovelace, the 2nd generation of ‘mad, bad, and dangerous to know’

A mathematician and genius in her own right, Ada Lovelace’s father George Gordon Byron, better known as the poet Lord Byron, was notoriously described as ‘mad, bad, and dangerous to know’.

Lovelace too could have been been ‘mad, bad, …’ but she is described less memorably as “… manipulative and aggressive, a drug addict, a gambler and an adulteress, …” as mentioned in my October 13, 20215 posting. It marked the 200th anniversary of her birth, which was celebrated with a British Broadcasting Corporation (BBC) documentary and an exhibit at the Science Museum in London, UK.

She belongs in the Vancouver Art Gallery’s show along with Alan Turing due to her prediction that computers could be made to create music. She also published the first computer program. Her feat is astonishing when you know only one working model {1/7th of the proposed final size) of a computer was ever produced. (The machine invented by Charles Babbage was known as a difference engine. You can find out more about the Difference engine on Wikipedia and about Babbage’s proposed second invention, the Analytical engine.)

(Byron had almost nothing to do with his daughter although his reputation seems to have dogged her. You can find out more about Lord Byron here.)

AI and visual culture at the VAG: the curators

As mentioned earlier, the VAG’s “The Imitation Game: Visual Culture in the Age of Artificial Intelligence” show runs from March 5, 2022 – October 23, 2022. Twice now, I have been to this weirdly exciting and frustrating show.

Bruce Grenville, VAG Chief/Senior Curator, seems to specialize in pulling together diverse materials to illustrate ‘big’ topics. His profile for Emily Carr University of Art + Design (where Grenville teaches) mentions these shows ,

… He has organized many thematic group exhibitions including, MashUp: The Birth of Modern Culture [emphasis mine], a massive survey documenting the emergence of a mode of creativity that materialized in the late 1800s and has grown to become the dominant model of cultural production in the 21st century; KRAZY! The Delirious World [emphasis mine] of Anime + Manga + Video Games + Art, a timely and important survey of modern and contemporary visual culture from around the world; Home and Away: Crossing Cultures on the Pacific Rim [emphasis mine] a look at the work of six artists from Vancouver, Beijing, Ho Chi Minh City, Seoul and Los Angeles, who share a history of emigration and diaspora. …

Glenn Entis, Guest Curator and founding faculty member of Vancouver’s Centre for Digital Media (CDM) is Grenville’s co-curator, from Entis’ CDM profile,

“… an Academy Award-winning animation pioneer and games industry veteran. The former CEO of Dreamworks Interactive, Glenn worked with Steven Spielberg and Jeffrey Katzenberg on a number of video games …,”

Steve Newton in his March 4, 2022 preview does a good job of describing the show although I strongly disagree with the title of his article which proclaims “The Vancouver Art Gallery takes a deep dive into artificial intelligence with The Imitation Game.” I think it’s more of a shallow dive meant to cover more distance than depth,

… The exhibition kicks off with an interactive introduction inviting visitors to actively identify diverse areas of cultural production influenced by AI.

“That was actually one of the pieces that we produced in collaboration with the Centre for Digital Media,” Grenville notes, “so we worked with some graduate-student teams that had actually helped us to design that software. It was the beginning of COVID when we started to design this, so we actually wanted a no-touch interactive. So, really, the idea was to say, ‘Okay, this is the very entrance to the exhibition, and artificial intelligence, this is something I’ve heard about, but I’m not really sure how it’s utilized in ways. But maybe I know something about architecture; maybe I know something about video games; maybe I know something about the history of film.

“So you point to these 10 categories of visual culture [emphasis mine]–video games, architecture, fashion design, graphic design, industrial design, urban design–so you point to one of those, and you might point to ‘film’, and then when you point at it that opens up into five different examples of what’s in the show, so it could be 2001: A Space Odyssey, or Bladerunner, or World on a Wire.”

After the exhibition’s introduction—which Grenville equates to “opening the door to your curiosity” about artificial intelligence–visitors encounter one of its main categories, Objects of Wonder, which speaks to the history of AI and the critical advances the technology has made over the years.

“So there are 20 Objects of Wonder [emphasis mine],” Grenville says, “which go from 1949 to 2022, and they kind of plot out the history of artificial intelligence over that period of time, focusing on a specific object. Like [mathematician and philosopher] Norbert Wiener made this cybernetic creature, he called it a ‘Moth’, in 1949. So there’s a section that looks at this idea of kind of using animals–well, machine animals–and thinking about cybernetics, this idea of communication as feedback, early thinking around neuroscience and how neuroscience starts to imagine this idea of a thinking machine.

And there’s this from Newton’s March 4, 2022 preview,

“It’s interesting,” Grenville ponders, “artificial intelligence is virtually unregulated. [emphasis mine] You know, if you think about the regulatory bodies that govern TV or radio or all the types of telecommunications, there’s no equivalent for artificial intelligence, which really doesn’t make any sense. And so what happens is, sometimes with the best intentions [emphasis mine]—sometimes not with the best intentions—choices are made about how artificial intelligence develops. So one of the big ones is facial-recognition software [emphasis mine], and any body-detection software that’s being utilized.

In addition to it being the best overview of the show I’ve seen so far, this is the only one where you get a little insight into what the curators were thinking when they were developing it.

A deep dive into AI?

it was only while searching for a little information before the show that I realized I don’t have any definitions for artificial intelligence! What is AI? Sadly, there are no definitions of AI in the exhibit.

It seems even experts don’t have a good definition. Take a look at this,

The definition of AI is fluid [emphasis mine] and reflects a constantly shifting landscape marked by technological advancements and growing areas of application. Indeed, it has frequently been observed that once AI becomes capable of solving a particular problem or accomplishing a certain task, it is often no longer considered to be “real” intelligence [emphasis mine] (Haenlein & Kaplan, 2019). A firm definition was not applied for this report [emphasis mine], given the variety of implementations described above. However, for the purposes of deliberation, the Panel chose to interpret AI as a collection of statistical and software techniques, as well as the associated data and the social context in which they evolve — this allows for a broader and more inclusive interpretation of AI technologies and forms of agency. The Panel uses the term AI interchangeably to describe various implementations of machine-assisted design and discovery, including those based on machine learning, deep learning, and reinforcement learning, except for specific examples where the choice of implementation is salient. [p. 6 print version; p. 34 PDF version]

The above is from the Leaps and Boundaries report released May 10, 2022 by the Council of Canadian Academies’ Expert Panel on Artificial Intelligence for Science and Engineering.

Sometimes a show will take you in an unexpected direction. I feel a lot better ‘not knowing’. Still, I wish the curators had acknowledged somewhere in the show that artificial intelligence is a slippery concept. Especially when you add in robots and automatons. (more about them later)

21st century technology in a 19th/20th century building

Void stairs inside the building. Completed in 1906, the building was later designated as a National Historic Site in 1980 [downloaded from https://en.wikipedia.org/wiki/Vancouver_Art_Gallery#cite_note-canen-7]

Just barely making it into the 20th century, the building where the Vancouver Art Gallery currently resides was for many years the provincial courthouse (1911 – 1978). In some ways, it’s a disconcerting setting for this show.

They’ve done their best to make the upstairs where the exhibit is displayed look like today’s galleries with their ‘white cube aesthetic’ and strong resemblance to the scientific laboratories seen in movies.

(For more about the dominance, since the 1930s, of the ‘white cube aesthetic’ in art galleries around the world, see my July 26, 2021 posting; scroll down about 50% of the way.)

It makes for an interesting tension, the contrast between the grand staircase, the cupola, and other architectural elements and the sterile, ‘laboratory’ environment of the modern art gallery.

20 Objects of Wonder and the flow of the show

It was flummoxing. Where are the 20 objects? Why does it feel like a maze in a laboratory? Loved the bees, but why? Eeeek Creepers! What is visual culture anyway? Where am I?

The objects of the show

It turns out that the curators have a more refined concept for ‘object’ than I do. There weren’t 20 material objects, there were 20 numbered ‘pods’ with perhaps a screen or a couple of screens or a screen and a material object or two illustrating the pod’s topic.

Looking up a definition for the word (accessed from a June 9, 2022 duckduckgo.com search). yielded this, (the second one seems à propos),

objectŏb′jĭkt, -jĕkt″

noun

1. Something perceptible by one or more of the senses, especially by vision or touch; a material thing.

2. A focus of attention, feeling, thought, or action.

3. A limiting factor that must be considered.

The American Heritage® Dictionary of the English Language, 5th Edition.

Each pod = a focus of attention.

The show’s flow is a maze. Am I a rat?

The pods are defined by a number and by temporary walls. So if you look up, you’ll see a number and a space partly enclosed by a temporary wall or two.

It’s a very choppy experience. For example, one minute you can be in pod 1 and, when you turn the corner, you’re in pod 4 or 5 or ? There are pods I’ve not seen, despite my two visits, because I kept losing my way. This led to an existential crisis on my second visit. “Had I missed the greater meaning of this show? Was there some sort of logic to how it was organized? Was there meaning to my life? Was I a rat being nudged around in a maze?” I didn’t know.

Thankfully, I have since recovered. But, I will return to my existential crisis later, with a special mention for “Creepers.”

The fascinating

My friend, you know I appreciated the history and in addition to Alan Turing, Ada Lovelace and the Mechanical Turk, at the beginning of the show, they included a reference to Ovid (or Pūblius Ovidius Nāsō), a Roman poet who lived from 43 BCE – 17/18 CE in one of the double digit (17? or 10? or …) in one of the pods featuring a robot on screen. As to why Ovid might be included, this excerpt from a February 12, 2018 posting on the cosmolocal.org website provides a clue (Note. Links have been removed),

The University of King’s College [Halifax, Nova Scotia] presents Automatons! From Ovid to AI, a nine-lecture series examining the history, issues and relationships between humans, robots, and artificial intelligence [emphasis mine]. The series runs from January 10 to April 4 [2018], and features leading scholars, performers and critics from Canada, the US and Britain.

“Drawing from theatre, literature, art, science and philosophy, our 2018 King’s College Lecture Series features leading international authorities exploring our intimate relationships with machines,” says Dr. Gordon McOuat, professor in the King’s History of Science and Technology (HOST) and Contemporary Studies Programs.

“From the myths of Ovid [emphasis mine] and the automatons [emphasis mine] of the early modern period to the rise of robots, cyborgs, AI and artificial living things in the modern world, the 2018 King’s College Lecture Series examines the historical, cultural, scientific and philosophical place of automatons in our lives—and our future,” adds McOuat.

I loved the way the curators managed to integrate the historical roots for artificial intelligence and, by extension, the world of automatons, robots, cyborgs, and androids. Yes, starting the show with Alan Turing and Ada Lovelace could be expected but Norbert Wiener’s Moth (1949) acts as a sort of preview for Sougwen Chung’s “Omnia per Omnia, 2018” (GIF seen at the beginning of this post). Take a look for yourself (from the cyberneticzoo.com September 19, 2009 posting by cyberne1. Do you see the similarity or am I the only one?

[sourced from Google images, Source:life) & downloaded from https://cyberneticzoo.com/cyberneticanimals/1949-wieners-moth-wiener-wiesner-singleton/]

Sculpture

This is the first time I’ve come across an AI/sculpture project. The VAG show features Scott Eaton’s sculptures on screens in a room devoted to his work.

Scott Eaton: Entangled II, 2019 4k video (still) Courtesy of the Artist [downloaded from https://www.vanartgallery.bc.ca/exhibitions/the-imitation-game]

This looks like an image of a piece of ginger root and It’s fascinating to watch the process as the AI agent ‘evolves’ Eaton’s drawings into onscreen sculptures. It would have enhanced the experience if at least one of Eaton’s ‘evolved’ and physically realized sculptures had been present in the room but perhaps there were financial and/or logistical reasons for the absence.

Both Chung and Eaton are collaborating with an AI agent. In Chung’s case the AI is integrated into the paintbots with which she interacts and paints alongside and in Eaton’s case, it’s via a computer screen. In both cases, the work is mildly hypnotizing in a way that reminds me of lava lamps.

One last note about Chung and her work. She was one of the artists invited to present new work at an invite-only April 22, 2022 Embodied Futures workshop at the “What will life become?” event held by the Berrgruen Institute and the University of Southern California (USC),

Embodied Futures invites participants to imagine novel forms of life, mind, and being through artistic and intellectual provocations on April 22 [2022].

Beginning at 1 p.m., together we will experience the launch of five artworks commissioned by the Berggruen Institute. We asked these artists: How does your work inflect how we think about “the human” in relation to alternative “embodiments” such as machines, AIs, plants, animals, the planet, and possible alien life forms in the cosmos? [emphases mine]  Later in the afternoon, we will take provocations generated by the morning’s panels and the art premieres in small breakout groups that will sketch futures worlds, and lively entities that might dwell there, in 2049.

This leads to (and my friend, while I too am taking a shallow dive, for this bit I’m going a little deeper):

Bees and architecture

Neri Oxman’s contribution (Golden Bee Cube, Synthetic Apiary II [2020]) is an exhibit featuring three honeycomb structures and a video featuring the bees in her synthetic apiary.

Neri Oxman and the MIT Mediated Matter Group, Golden Bee Cube, Synthetic Apiary II, 2020, beeswax, acrylic, gold particles, gold powder Courtesy of Neri Oxman and the MIT Mediated Matter Group

Neri Oxman (then a faculty member of the Mediated Matter Group at the Massachusetts Institute of Technology) described the basis for the first and all other iterations of her synthetic apiary in Patrick Lynch’s October 5, 2016 article for ‘ArchDaily; Broadcasting Architecture Worldwide’, Note: Links have been removed,

Designer and architect Neri Oxman and the Mediated Matter group have announced their latest design project: the Synthetic Apiary. Aimed at combating the massive bee colony losses that have occurred in recent years, the Synthetic Apiary explores the possibility of constructing controlled, indoor environments that would allow honeybee populations to thrive year-round.

“It is time that the inclusion of apiaries—natural or synthetic—for this “keystone species” be considered a basic requirement of any sustainability program,” says Oxman.

In developing the Synthetic Apiary, Mediated Matter studied the habits and needs of honeybees, determining the precise amounts of light, humidity and temperature required to simulate a perpetual spring environment. [emphasis mine] They then engineered an undisturbed space where bees are provided with synthetic pollen and sugared water and could be evaluated regularly for health.

In the initial experiment, the honeybees’ natural cycle proved to adapt to the new environment, as the Queen was able to successfully lay eggs in the apiary. The bees showed the ability to function normally in the environment, suggesting that natural cultivation in artificial spaces may be possible across scales, “from organism- to building-scale.”

“At the core of this project is the creation of an entirely synthetic environment enabling controlled, large-scale investigations of hives,” explain the designers.

Mediated Matter chose to research into honeybees not just because of their recent loss of habitat, but also because of their ability to work together to create their own architecture, [emphasis mine] a topic the group has explored in their ongoing research on biologically augmented digital fabrication, including employing silkworms to create objects and environments at product, architectural, and possibly urban, scales.

“The Synthetic Apiary bridges the organism- and building-scale by exploring a “keystone species”: bees. Many insect communities present collective behavior known as “swarming,” prioritizing group over individual survival, while constantly working to achieve common goals. Often, groups of these eusocial organisms leverage collaborative behavior for relatively large-scale construction. For example, ants create extremely complex networks by tunneling, wasps generate intricate paper nests with materials sourced from local areas, and bees deposit wax to build intricate hive structures.”

This January 19, 2022 article by Crown Honey for its eponymous blog updates Oxman’s work (Note 1: All emphases are mine; Note 2: A link has been removed),

Synthetic Apiary II investigates co-fabrication between humans and honey bees through the use of designed environments in which Apis mellifera colonies construct comb. These designed environments serve as a means by which to convey information to the colony. The comb that the bees construct within these environments comprises their response to the input information, enabling a form of communication through which we can begin to understand the hive’s collective actions from their perspective.

Some environments are embedded with chemical cues created through a novel pheromone 3D-printing process, while others generate magnetic fields of varying strength and direction. Others still contain geometries of varying complexity or designs that alter their form over time.

When offered wax augmented with synthetic biomarkers, bees appear to readily incorporate it into their construction process, likely due to the high energy cost of producing fresh wax. This suggests that comb construction is a responsive and dynamic process involving complex adaptations to perturbations from environmental stimuli, not merely a set of predefined behaviors building toward specific constructed forms. Each environment therefore acts as a signal that can be sent to the colony to initiate a process of co-fabrication.

Characterization of constructed comb morphology generally involves visual observation and physical measurements of structural features—methods which are limited in scale of analysis and blind to internal architecture. In contrast, the wax structures built by the colonies in Synthetic Apiary II are analyzed through high-throughput X-ray computed tomography (CT) scans that enable a more holistic digital reconstruction of the hive’s structure.

Geometric analysis of these forms provides information about the hive’s design process, preferences, and limitations when tied to the inputs, and thereby yields insights into the invisible mediations between bees and their environment.
Developing computational tools to learn from bees can facilitate the very beginnings of a dialogue with them. Refined by evolution over hundreds of thousands of years, their comb-building behaviors and social organizations may reveal new forms and methods of formation that can be applied across our human endeavors in architecture, design, engineering, and culture.

Further, with a basic understanding and language established, methods of co-fabrication together with bees may be developed, enabling the use of new biocompatible materials and the creation of more efficient structural geometries that modern technology alone cannot achieve.

In this way, we also move our built environment toward a more synergistic embodiment, able to be more seamlessly integrated into natural environments through material and form, even providing habitats of benefit to both humans and nonhumans. It is essential to our mutual survival for us to not only protect but moreover to empower these critical pollinators – whose intrinsic behaviors and ecosystems we have altered through our industrial processes and practices of human-centric design – to thrive without human intervention once again.

In order to design our way out of the environmental crisis that we ourselves created, we must first learn to speak nature’s language. …

The three (natural, gold nanoparticle, and silver nanoparticle) honeycombs in the exhibit are among the few physical objects (the others being the historical documents and the paintbots with their canvasses) in the show and it’s almost a relief after the parade of screens. It’s the accompanying video that’s eerie. Everything is in white, as befits a science laboratory, in this synthetic apiary where bees are fed sugar water and fooled into a spring that is eternal.

Courtesy: Massachusetts Institute of Technology Copyright: Mediated Matter [downloaded from https://www.media.mit.edu/projects/synthetic-apiary/overview/]

(You may want to check out Lynch’s October 5, 2016 article or Crown Honey’s January 19, 2022 article as both have embedded images and the Lynch article includes a Synthetic Apiary video. The image above is a still from the video.)

As I asked a friend, where are the flowers? Ron Miksha, a bee ecologist working at the University of Calgary, details some of the problems with Oxman’s Synthetic Apiary this way in his October 7, 2016 posting on his Bad Beekeeping Blog,

In a practical sense, the synthetic apiary fails on many fronts: Bees will survive a few months on concoctions of sugar syrup and substitute pollen, but they need a natural variety of amino acids and minerals to actually thrive. They need propolis and floral pollen. They need a ceiling 100 metres high and a 2-kilometre hallway if drone and queen will mate, or they’ll die after the old queen dies. They need an artificial sun that travels across the sky, otherwise, the bees will be attracted to artificial lights and won’t return to their hive. They need flowery meadows, fresh water, open skies. [emphasis mine] They need a better holodeck.

Dorothy Woodend’s March 10, 2022 review of the VAG show for The Tyee poses other issues with the bees and the honeycombs,

When AI messes about with other species, there is something even more unsettling about the process. American-Israeli artist Neri Oxman’s Golden Bee Cube, Synthetic Apiary II, 2020 uses real bees who are proffered silver and gold [nanoparticles] to create their comb structures. While the resulting hives are indeed beautiful, rendered in shades of burnished metal, there is a quality of unease imbued in them. Is the piece akin to apiary torture chambers? I wonder how the bees feel about this collaboration and whether they’d like to renegotiate the deal.

There’s no question the honeycombs are fascinating and disturbing but I don’t understand how artificial intelligence was a key factor in either version of Oxman’s synthetic apiary. In the 2022 article by Crown Honey, there’s this “Developing computational tools to learn from bees can facilitate the very beginnings of a dialogue with them [honeybees].” It’s probable that the computational tools being referenced include AI and the Crown Honey article seems to suggest those computational tools are being used to analyze the bees behaviour after the fact.

Yes, I can imagine a future where ‘strong’ AI (such as you, my friend) is in ‘dialogue’ with the bees and making suggestions and running the experiments but it’s not clear that this is the case currently. The Oxman exhibit contribution would seem to be about the future and its possibilities whereas many of the other ‘objects’ concern the past and/or the present.

Friend, let’s take a break, shall we? Part 2 is coming up.

Windows and roofs ‘self-adapt’ to heating and cooling conditions

I have two items about thermochromic coatings. It’s a little confusing since the American Association for the Advancement of Science (AAAS), which publishes the journal featuring both papers has issued a news release that seemingly refers to both papers as a single piece of research.

Onto, the press/new releases from the research institutions to be followed by the AAAS news release.

Nanyang Technological University (NTU) does windows

A December 16, 2021 news item on Nanowerk announced work on energy-saving glass,

An international research team led by scientists from Nanyang Technological University, Singapore (NTU Singapore) has developed a material that, when coated on a glass window panel, can effectively self-adapt to heat or cool rooms across different climate zones in the world, helping to cut energy usage.

Developed by NTU researchers and reported in the journal Science (“Scalable thermochromic smart windows with passive radiative cooling regulation”), the first-of-its-kind glass automatically responds to changing temperatures by switching between heating and cooling.

The self-adaptive glass is developed using layers of vanadium dioxide nanoparticles composite, Poly(methyl methacrylate) (PMMA), and low-emissivity coating to form a unique structure which could modulate heating and cooling simultaneously.

A December 17, 2021 NTU press release (PDF), also on EurekAlert but published December 16, 2021, which originated the news item, delves further into the research (Note: A link has been removed),

The newly developed glass, which has no electrical components, works by exploiting the spectrums of light responsible for heating and cooling.

During summer, the glass suppresses solar heating (near infrared light), while boosting radiative cooling (long-wave infrared) – a natural phenomenon where heat emits through surfaces towards the cold universe – to cool the room. In the winter, it does the opposite to warm up the room.

In lab tests using an infrared camera to visualise results, the glass allowed a controlled amount of heat to emit in various conditions (room temperature – above 70°C), proving its ability to react dynamically to changing weather conditions.

New glass regulates both heating and cooling

Windows are one of the key components in a building’s design, but they are also the least energy-efficient and most complicated part. In the United States alone, window-associated energy consumption (heating and cooling) in buildings accounts for approximately four per cent of their total primary energy usage each year according to an estimation based on data available from the Department of Energy in US.[1]

While scientists elsewhere have developed sustainable innovations to ease this energy demand – such as using low emissivity coatings to prevent heat transfer and electrochromic glass that regulate solar transmission from entering the room by becoming tinted – none of the solutions have been able to modulate both heating and cooling at the same time, until now.

The principal investigator of the study, Dr Long Yi of the NTU School of Materials Science and Engineering (MSE) said, “Most energy-saving windows today tackle the part of solar heat gain caused by visible and near infrared sunlight. However, researchers often overlook the radiative cooling in the long wavelength infrared. While innovations focusing on radiative cooling have been used on walls and roofs, this function becomes undesirable during winter. Our team has demonstrated for the first time a glass that can respond favourably to both wavelengths, meaning that it can continuously self-tune to react to a changing temperature across all seasons.”

As a result of these features, the NTU research team believes their innovation offers a convenient way to conserve energy in buildings since it does not rely on any moving components, electrical mechanisms, or blocking views, to function.

To improve the performance of windows, the simultaneous modulation of both solar transmission and radiative cooling are crucial, said co-authors Professor Gang Tan from The University of Wyoming, USA, and Professor Ronggui Yang from the Huazhong University of Science and Technology, Wuhan, China, who led the building energy saving simulation.

“This innovation fills the missing gap between traditional smart windows and radiative cooling by paving a new research direction to minimise energy consumption,” said Prof Gang Tan.

The study is an example of groundbreaking research that supports the NTU 2025 strategic plan, which seeks to address humanity’s grand challenges on sustainability, and accelerate the translation of research discoveries into innovations that mitigate human impact on the environment.

Innovation useful for a wide range of climate types

As a proof of concept, the scientists tested the energy-saving performance of their invention using simulations of climate data covering all populated parts of the globe (seven climate zones).

The team found the glass they developed showed energy savings in both warm and cool seasons, with an overall energy saving performance of up to 9.5%, or ~330,000 kWh per year (estimated energy required to power 60 household in Singapore for a year) less than commercially available low emissivity glass in a simulated medium sized office building.

First author of the study Wang Shancheng, who is Research Fellow and former PhD student of Dr Long Yi, said, “The results prove the viability of applying our glass in all types of climates as it is able to help cut energy use regardless of hot and cold seasonal temperature fluctuations. This sets our invention apart from current energy-saving windows which tend to find limited use in regions with less seasonal variations.”

Moreover, the heating and cooling performance of their glass can be customised to suit the needs of the market and region for which it is intended.

“We can do so by simply adjusting the structure and composition of special nanocomposite coating layered onto the glass panel, allowing our innovation to be potentially used across a wide range of heat regulating applications, and not limited to windows,” Dr Long Yi said.

Providing an independent view, Professor Liangbing Hu, Herbert Rabin Distinguished Professor, Director of the Center for Materials Innovation at the University of Maryland, USA, said, “Long and co-workers made the original development of smart windows that can regulate the near-infrared sunlight and the long-wave infrared heat. The use of this smart window could be highly important for building energy-saving and decarbonization.”  

A Singapore patent has been filed for the innovation. As the next steps, the research team is aiming to achieve even higher energy-saving performance by working on the design of their nanocomposite coating.

The international research team also includes scientists from Nanjing Tech University, China. The study is supported by the Singapore-HUJ Alliance for Research and Enterprise (SHARE), under the Campus for Research Excellence and Technological Enterprise (CREATE) programme, Minster of Education Research Fund Tier 1, and the Sino-Singapore International Joint Research Institute.

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

Scalable thermochromic smart windows with passive radiative cooling regulation by Shancheng Wang, Tengyao Jiang, Yun Meng, Ronggui Yang, Gang Tan, and Yi Long. Science • 16 Dec 2021 • Vol 374, Issue 6574 • pp. 1501-1504 • DOI: 10.1126/science.abg0291

This paper is behind a paywall.

Lawrence Berkeley National Laboratory (Berkeley Lab; LBNL) does roofs

A December 16, 2021 Lawrence Berkeley National Laboratory news release (also on EurekAlert) announces an energy-saving coating for roofs (Note: Links have been removed),

Scientists have developed an all-season smart-roof coating that keeps homes warm during the winter and cool during the summer without consuming natural gas or electricity. Research findings reported in the journal Science point to a groundbreaking technology that outperforms commercial cool-roof systems in energy savings.

“Our all-season roof coating automatically switches from keeping you cool to warm, depending on outdoor air temperature. This is energy-free, emission-free air conditioning and heating, all in one device,” said Junqiao Wu, a faculty scientist in Berkeley Lab’s Materials Sciences Division and a UC Berkeley professor of materials science and engineering who led the study.

Today’s cool roof systems, such as reflective coatings, membranes, shingles, or tiles, have light-colored or darker “cool-colored” surfaces that cool homes by reflecting sunlight. These systems also emit some of the absorbed solar heat as thermal-infrared radiation; in this natural process known as radiative cooling, thermal-infrared light is radiated away from the surface.

The problem with many cool-roof systems currently on the market is that they continue to radiate heat in the winter, which drives up heating costs, Wu explained.

“Our new material – called a temperature-adaptive radiative coating or TARC – can enable energy savings by automatically turning off the radiative cooling in the winter, overcoming the problem of overcooling,” he said.

A roof for all seasons

Metals are typically good conductors of electricity and heat. In 2017, Wu and his research team discovered that electrons in vanadium dioxide behave like a metal to electricity but an insulator to heat – in other words, they conduct electricity well without conducting much heat. “This behavior contrasts with most other metals where electrons conduct heat and electricity proportionally,” Wu explained.

Vanadium dioxide below about 67 degrees Celsius (153 degrees Fahrenheit) is also transparent to (and hence not absorptive of) thermal-infrared light. But once vanadium dioxide reaches 67 degrees Celsius, it switches to a metal state, becoming absorptive of thermal-infrared light. This ability to switch from one phase to another – in this case, from an insulator to a metal – is characteristic of what’s known as a phase-change material.

To see how vanadium dioxide would perform in a roof system, Wu and his team engineered a 2-centimeter-by-2-centimeter TARC thin-film device.

TARC “looks like Scotch tape, and can be affixed to a solid surface like a rooftop,” Wu said.

In a key experiment, co-lead author Kechao Tang set up a rooftop experiment at Wu’s East Bay home last summer to demonstrate the technology’s viability in a real-world environment.

A wireless measurement device set up on Wu’s balcony continuously recorded responses to changes in direct sunlight and outdoor temperature from a TARC sample, a commercial dark roof sample, and a commercial white roof sample over multiple days.

How TARC outperforms in energy savings

The researchers then used data from the experiment to simulate how TARC would perform year-round in cities representing 15 different climate zones across the continental U.S.

Wu enlisted Ronnen Levinson, a co-author on the study who is a staff scientist and leader of the Heat Island Group in Berkeley Lab’s Energy Technologies Area, to help them refine their model of roof surface temperature. Levinson developed a method to estimate TARC energy savings from a set of more than 100,000 building energy simulations that the Heat Island Group previously performed to evaluate the benefits of cool roofs and cool walls across the United States.

Finnegan Reichertz, a 12th grade student at the East Bay Innovation Academy in Oakland who worked remotely as a summer intern for Wu last year, helped to simulate how TARC and the other roof materials would perform at specific times and on specific days throughout the year for each of the 15 cities or climate zones the researchers studied for the paper.

The researchers found that TARC outperforms existing roof coatings for energy saving in 12 of the 15 climate zones, particularly in regions with wide temperature variations between day and night, such as the San Francisco Bay Area, or between winter and summer, such as New York City.

“With TARC installed, the average household in the U.S. could save up to 10% electricity,” said Tang, who was a postdoctoral researcher in the Wu lab at the time of the study. He is now an assistant professor at Peking University in Beijing, China.

Standard cool roofs have high solar reflectance and high thermal emittance (the ability to release heat by emitting thermal-infrared radiation) even in cool weather.

According to the researchers’ measurements, TARC reflects around 75% of sunlight year-round, but its thermal emittance is high (about 90%) when the ambient temperature is warm (above 25 degrees Celsius or 77 degrees Fahrenheit), promoting heat loss to the sky. In cooler weather, TARC’s thermal emittance automatically switches to low, helping to retain heat from solar absorption and indoor heating, Levinson said.

Findings from infrared spectroscopy experiments using advanced tools at Berkeley Lab’s Molecular Foundry validated the simulations.

“Simple physics predicted TARC would work, but we were surprised it would work so well,” said Wu. “We originally thought the switch from warming to cooling wouldn’t be so dramatic. Our simulations, outdoor experiments, and lab experiments proved otherwise – it’s really exciting.”

The researchers plan to develop TARC prototypes on a larger scale to further test its performance as a practical roof coating. Wu said that TARC may also have potential as a thermally protective coating to prolong battery life in smartphones and laptops, and shield satellites and cars from extremely high or low temperatures. It could also be used to make temperature-regulating fabric for tents, greenhouse coverings, and even hats and jackets.

Co-lead authors on the study were Kaichen Dong and Jiachen Li.

The Molecular Foundry is a nanoscience user facility at Berkeley Lab.

This work was primarily supported by the DOE Office of Science and a Bakar Fellowship.

The technology is available for licensing and collaboration. If interested, please contact Berkeley Lab’s Intellectual Property Office, ipo@lbl.gov.

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

Temperature-adaptive radiative coating for all-season household thermal regulation by Kechao Tang, Kaichen Dong, Jiachen Li, Madeleine P. Gordon, Finnegan G. Reichertz, Hyungjin Kim, Yoonsoo Rho, Qingjun Wang, Chang-Yu Lin, Costas P. Grigoropoulos, Ali Javey, Jeffrey J. Urban, Jie Yao, Ronnen Levinson, Junqiao Wu. Science • 16 Dec 2021 • Vol 374, Issue 6574 • pp. 1504-1509 • DOI: 10.1126/science.abf7136

This paper is behind a paywall.

An interesting news release from the AAAS

While it’s a little confusing as it cites only the ‘window’ research from NTU, the body of this news release offers some additional information about the usefulness of thermochromic materials and seemingly refers to both papers, from a December 16, 2021 AAAS news release,

Temperature-adaptive passive radiative cooling for roofs and windows

When it’s cold out, window glass and roof coatings that use passive radiative cooling to keep buildings cool can be designed to passively turn off radiative cooling to avoid heat loss, two new studies show.  Their proof-of-concept analyses demonstrate that passive radiative cooling can be expanded to warm and cold climate applications and regions, potentially providing all-season energy savings worldwide. Buildings consume roughly 40% of global energy, a large proportion of which is used to keep them cool in warmer climates. However, most temperature regulation systems commonly employed are not very energy efficient and require external power or resources. In contrast, passive radiative cooling technologies, which use outer space as a near-limitless natural heat sink, have been extensively examined as a means of energy-efficient cooling for buildings. This technology uses materials designed to selectively emit narrow-band radiation through the infrared atmospheric window to disperse heat energy into the coldness of space. However, while this approach has proven effective in cooling buildings to below ambient temperatures, it is only helpful during the warmer months or in regions that are perpetually hot. Furthermore, the inability to “turn off” passive cooling in cooler climes or in regions with large seasonal temperature variations means that continuous cooling during colder periods would exacerbate the energy costs of heating. In two different studies, by Shancheng Wang and colleagues and Kechao Tang and colleagues, researchers approach passive radiative cooling from an all-season perspective and present a new, scalable temperature-adaptive radiative technology that passively turns off radiative cooling at lower temperatures. Wang et al. and Tang et al. achieve this using a tungsten-doped vanadium dioxide and show how it can be applied to create both window glass and a flexible roof coating, respectively. Model simulations of the self-adapting materials suggest they could provide year-round energy savings across most climate zones, especially those with substantial seasonal temperature variations. 

I wish them all good luck with getting these materials to market.

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.