Extracting some of that moisture is seen as a potential way to provide clean drinking water to billions of people globally who face chronic shortages.

Existing technologies for atmospheric water harvesting (AWH) are saddled with numerous downsides associated with size, cost and efficiency. But new research from University of Utah engineering researchers has yielded insights that could improve efficiencies and bring the world one step closer to tapping the air as a culinary water source in arid places.

The study unveils the first-of-its-kind compact rapid cycling fuel-fired AWH device. This two-step prototype relies on adsorbent materials that draw water molecules out of non-humid air, then applies heat to release those molecules into liquid form, according to Sameer Rao, senior author of the study published Monday and an assistant professor of mechanical engineering.

“Hygroscopic materials intrinsically have affinity to water. They soak up water wherever you go. One of the best examples is the stuff inside diapers,” said Rao, who happens to be the father of an infant son. “We work with a specific type of hygroscopic material called a metal organic framework.”

Rao likened metal organic frameworks to Lego blocks, which can be rearranged to build all sorts of structures. It this case they are arranged to create a molecule ideal for gas separation.

“They can make it specific to adsorb water vapor from the air and nothing else. They’re really selective,” Rao said. Developed with graduate student Nathan Ortiz, the study’s lead author, this prototype uses aluminum fumarate that was fashioned into panels that collect the water as air is drawn through.

“The water molecules themselves get trapped on the surfaces of our material, and that’s a reversible process. And so instead of becoming ingrained into the material itself, it sits on the walls,” Ortiz said. “What’s special about these absorbent materials is they have just an immense amount of internal surface area. There’s so many sites for water molecules to get stuck.”

Just a gram of this material holds as much surface area as two football fields, according to Rao. So just a little material can capture a lot of water.

“All of this surface area is at the molecular scale,” Rao said. “And that’s awesome for us because we want to trap water vapor onto that surface area within the pores of this material.”

Funding for the research came from the DEVCOM Soldier Center, a program run by the Department of Defense to facilitate technology transfer that supports Army modernization. The Army’s interest in the project stems from the need to keep soldiers hydrated while operating in remote areas with few water sources.

“We specifically looked at this for defense applications so that soldiers have a small compact water generation unit and don’t need to lug around a large canteen filled with water,” Rao said. “This would literally produce water on demand.”

Rao and Ortiz have filed for a preliminary patent based on the technology, which addresses non-military needs as well.

“As we were designing the system, I think we also had perspective of the broader water problem. It’s not just a defense issue, it’s very much a civilian issue,” Rao said. “We think in terms water consumption of a household for drinking water per day. That’s about 15 to 20 liters per day.”

In this proof of concept, the prototype achieved its target of producing 5 liters of water per day per kilogram of adsorbent material. In a matter of three days in the field, this devise would outperform packing water, according to Ortiz.

In the device’s second step, the water is precipitated into liquid by applying heat using a standard-issue Army camping stove. This works because of the exothermic nature of its water collecting process.

“As it collects water, it’s releasing little bits of heat. And then to reverse that, we add heat,” Ortiz said. “We just put a flame right under here, anything to get this temperature up. And then as we increase the temperature, we rapidly release the water molecules. Once we have a really humid airstream, that makes condensation at ambient temperature much easier.”

Nascent technologies abound for atmospheric water harvesting, which is more easily accomplished when the air is humid, but none has resulted in equipment that can be put to practical use in arid environments. Ortiz believes his device can be the first, mainly because it is powered with energy-dense fuel like the white gasoline used in camping stoves.

The team decided against using photovoltaics.

“If you’re reliant on solar panels, you’re limited to daytime operation or you need batteries, which is just more weight. You keep stacking challenges. It just takes up so much space,” Ortiz said. “This technology is superior in arid conditions, while refrigeration is best in high humidity.”

Solar panels made of perovskites may eventually play an important role amid global decarbonization efforts to reduce greenhouse gas emissions. As the technology emerges from the testing stages, it is a perfect time to think critically about how best to design the solar panels to minimize their impact on the environment decades from now.

“When you have a technology in its very early stages, you have the ability to design it better. It’s a cleaner slate,” said Joey Luther, a senior research fellow at the U.S. Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL) and coauthor of the newly published article in the journal Nature Materials. “Pushing perovskite PV toward enhanced sustainability makes more sense at this stage. We’re thinking about how we can make sure we have a sustainable product now rather than dealing with sustainability issues toward the end of its practical life.”

The PV research community, the article noted, is in an influential position to prioritize efforts in remanufacturing, recycling, (aka a “circular economy”) and reliability to make perovskite PV among the most sustainable energy sources on the market.

“Perovskites could unlock the next evolution of high-efficiency PV, and it is our responsibility to assure they are manufactured, used, and recycled sustainably,” said the lead author of the study, Kevin Prince, a former graduate researcher at NREL who is now researching perovskites at Helmholtz Zentrum Berlin in Germany.

Solar panels made from silicon dominate the industry, and while they have enormous environmental and climate benefits, they were not initially designed for “circularity.” The other leading solar technology, cadmium telluride (CdTe), has had an established recycling program from the technology’s inception partly to address the scarcity of telluride. All forms of tech manufacturing come with environmental costs, such as recycling challenges and the use of potentially toxic chemicals. But perovskites are at an inflection point, so the opportunity exists to address those concerns now.

The most efficient circular economy begins at the design stage and considers materials sourcing, strategizes for a long product lifetime, and plans end-of-life management. According to the researchers, the most representative way to assess the environmental impacts of solar panel manufacturing is to look at carbon emissions released during production, embodied energy, sustainable material sourcing, and module circularity.

The journal article identifies critical sustainability concerns for each component of a perovskite solar panel. Lead, for example, could be diluted with other chemically similar metals, such as tin, to lessen the amount of lead in a future panel. However, to date, these substitutions have come at the cost of PV efficiency and durability, requiring much more research before these proposed semiconductors are ready to use in modules. The researchers also suggest that expensive precious metals used in perovskite research cells, including silver and gold, should be replaced with low-cost alternatives, such as aluminum, copper, or nickel, for commercial modules. They also said fluorine-tin oxide would be a more practical material for the cell’s front electrodes rather than the scarcer indium used in indium-tin oxide.

“We want to have the lowest amount of embodied energy in the fabrication,” Luther said. “We want to have the lowest amount of emissions in the fabrication. At this stage, now is the chance to look at those components. I don’t think we have to change anything. It’s more a matter of what decisions should be made, and these arguments should certainly be discussed.”

The authors highlighted different ways to think about the circularity of perovskite panels. Remanufacturing, for example, comes into play when an old module is disassembled with the goal of using certain parts to make a new module. Recycling, meanwhile, calls for the conversion of waste materials into raw materials that can then be refined and reused. One component that requires attention is the specialized glass that provides structural support for perovskite solar modules and offers protection from the elements while remaining very clear to allow in a maximal amount of sunlight. Establishing a recycling pathway for the glass will become more critical as PV deployment grows. Glass manufacturing as it stands today requires raw materials and is an energy-intensive process.

Silvana Ovaitt, a PV researcher and coauthor of the paper, said that as the electricity in the grid itself gets cleaner, the manufacturing of the panels will also be cleaner, further reducing emissions.

“Another concern is the transportation of the final modules and the raw glass because those are the heaviest items,” Ovaitt said. “Local manufacturing will be a great way to reduce those carbon impacts.”

The researchers explain that increasing PV module durability, thereby increasing its useful lifetime, is a more effective approach to reducing the net energy, energy payback, and carbon emissions than designing for circularity alone. Even though a panel can be designed with the end in mind, a longer lifespan means it will not have to be recycled as often.

“Ultimately, we want to make them as durable as possible,” Luther said. “But we also want to consider the aspects of whenever that time does come. We want to be deliberate about how to take them apart and to reuse the critical components.”

The other coauthors, all from NREL, are Heather Mirletz, E. Ashley Gaulding, Lance Wheeler, Ross Kerner, Xiaopeng Zheng, Laura Schelhas, Paul Tracy, Colin Wolden, Joseph Berry, and Teresa Barnes.

The DOE Solar Energy Technologies Office funded the research.

NREL is the DOE’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by the Alliance for Sustainable Energy LLC.

One way to do that is to inject the CO₂ into a reservoir space that’s covered with a big lid — an impermeable caprock that can keep the gas in place and stop any upward flow in its tracks. That’s the model that petroleum exploration has relied on for decades when searching for oil traps, and it works for both oil and CO₂. But according to research led by The University of Texas at Austin’s Bureau of Economic Geology, subsurface reservoirs that are covered by a collection of hundreds of smaller lids — collectively called a “composite confining system” — may be the better option for keeping carbon trapped for the long term.

That’s good news for the carbon storage industry. This type of distributed system is common in a range of geological environments, including the Texas Gulf Coast.

“Directly under what is the largest concentration of emissions in the U.S. we have incredible reservoirs, but few regional seals. What we have instead, is lots and lots of discontinuous barriers to vertical flow,” said Alex Bump, a research associate professor at the Bureau’s Gulf Coast Carbon Center in the UT Jackson School of Geosciences. “There is a very local motivation for this research but the application is global.”

Many people working in carbon storage have roots in oil and gas — including Bump. The two industries share similar knowledge bases in reservoir geology and fluid dynamics. However, according to Bump, this has also led to some assumptions about optimal carbon storage scenarios — namely, that the same sort of caprock-sealed reservoirs that are proven oil traps should also be the preferred place to store carbon.

According to Bump, there are key differences between hydrocarbon production and carbon storage that suggest rethinking the inherited concepts.

“In petroleum, the goal of production favors large-volume, concentrated, mobile accumulations, so we explore for large traps, and high-permeability reservoirs with an impermeable seal,” said Bump.

That same model works for carbon storage, but the factors that make it ideal for petroleum production make it risky for storage, Bump said. For example, if there is a leak in the seal (such as an improperly decommissioned well), then there is a large, concentrated volume of CO₂ that can potentially leak out. In contrast, the multiple barriers of a composite confining systems not only help prevent escape but also help spread the CO₂ plume across the available pore space in a reservoir. In doing so, they effectively immobilize the CO₂. Even where there might be an escape path, there is little or no mobile CO₂ to feed it.

Bump compares the differences between a caprock and composite approach to catching a water leak with a bucket versus a pile of towels. Both can do the job. But there’s no risk of the water spilling with the towels. The towels simply soak it up.

In a paper published in the International Journal of Greenhouse Gas Control, Bump and colleagues at the Gulf Coast Carbon Center, Hailun Ni and Sahar Bakhshian, make the case for composite confining systems for CO₂ storage by presenting data from experimental models, numerical simulations and actual reservoirs. Their experiments and numerical models show that the length and frequency of the barriers are the two most influential factors when it comes to an effective confining system. They also found that the barriers don’t have to be particularly substantial to be effective. Even minor reductions in grain size between geologic layers are enough to divert the path of a rising CO₂ plume — helping to spread the gas laterally throughout the reservoir, with little migration toward the surface.

Bump said that next on the agenda is to spread the word about composite confining systems for carbon storage. He is currently working on developing a best-practices guide for finding and permitting these types of reservoirs for CO₂ storage.

“This is really about creating a user’s manual,” Bump said. “We’re figuring out how to take a good idea and apply it. There are already commercial projects moving forward with this on the Gulf Coast. We want to make it a standard part of the global toolkit for carbon storage.”

“There is a tremendous amount of interest in what enables wildfire ignitions and what can be done to prevent them,” said Erica Fleishman, an Oregon State University professor. “This database increases the ability to access relevant information and contribute to wildfire preparedness and prevention.”

The Fire Program Analysis Fire-Occurrence Database was developed in 2013 by the U.S. Forest Service and since been updated five times. It incorporates basic information such as ignition location, discovery date and final wildfire size.

The revised database now includes many new environmental and social factors, such as topography and vegetation, social vulnerability and economic justice metrics, and practical attributes such as the distance from the ignition to the nearest road.

In addition to aiding on-the-ground firefighters and managers, the database could also help power companies evaluate short-term risk when deciding whether to implement a public safety power shutoff or land management agencies determine whether to reduce access to public lands or restrict campfires during certain times of year, Fleishman said.

“There seem to be a lot of policies that are guided to some extent by intuition or emotions rather than by a large body of evidence,” she said. “These data present one way to increase the objective evidence to consider when making those decisions.”

The team, including Fleishman, and led by Yavar Pourmohamad, a doctoral student at Boise State University, and Mojtaba Sadegh, an associate professor at Boise State, added nearly 270 additional attributes. The database now includes information on 2.3 million fires in the United States from 1992 to 2020.

“This provides a considerably deeper understanding of the individual and compounded impact of these attributes on wildfire ignitions and size,” Pourmohamad said. “It also identifies the unequal effects of wildfires on distinct human populations and ecosystems, which can, in turn, inform efforts to reduce inequities.”

Information from the database can also be incorporated into artificial intelligence and machine learning models that explain drivers of past fires or project likelihoods or effects of future fires, said Fleishman, who is affiliated with OSU’s College of Earth, Ocean, and Atmospheric Sciences and also directs the Oregon Climate Change Research Institute.

“It’s amazing what you can infer when you have the computational capacity and this much information,” she said. “You can ask a lot of questions that inform different actions in different places and to understand what is associated with wildfire ignitions and fire effects.”

A paper outlining the database was recently published in the journal Earth System Science Data.

Other co-authors of the paper are Eric Henderson and Sawyer Ball of Boise State; John Abatzoglou, University of California, Merced; Erin Belval, Karen Short, Matthew Reeves and Julia Olszewski, USDA Forest Service Rocky Mountain Research Station; Nicholas Nauslar, National Weather Service Storm Prediction Center; Philip Higuera, University of Montana; Amir AghaKouchak, University of California, Irvine; and Jeffrey Prestemon, USDA Forest Service Southern Research Station.

The research was supported by the Joint Fire Science Program, a program of the U.S. Forest Service and U.S. Department of the Interior.

Last year, the world emitted more than 37 billion metric tons of carbon dioxide, setting a new record high. As a result, sucking CO₂ out of the atmosphere has become an increasingly popular idea. Governments worldwide are banking on this technology, called direct air capture, to help them achieve climate goals and avoid the worst consequences of climate change.

But despite more than a dozen direct air capture facilities being up and running around the globe already, the technology still faces major technological hurdles — including its own high energy use.

In a study published May 1 in the journal ACS Energy Letters, researchers at the University of Colorado Boulder and collaborators revealed that a popular approach many engineers are exploring to reduce those energy costs would, in reality, fail. The team, including scientists at the National Renewable Energy Laboratory in Golden, Colorado and Delft University of Technology in the Netherlands, also proposed an alternative, more sustainable design for capturing CO₂ and converting it to fuels.

“Ideally, we want to take CO₂ out of the air and keep it out of the air,” said first author Hussain Almajed, a Ph.D. student in the Department of Chemical and Biological Engineering. “However, some of this CO₂ can be recycled into useful carbon-containing products, which is why researchers have proposed different ideas of how we can achieve that. Some of these ideas look very simple and elegant on paper, but researchers rarely check whether they are practical and economical in industrial settings.”

Trapping the gas

One of the most common direct air capture approaches is to use air contactors, essentially huge fans that pull air into a chamber filled with a basic liquid. CO₂ is acidic, so it naturally binds to and reacts with the solution to form harmless carbonate (the main ingredient in concrete) or bicarbonate (the ingredient in baking soda).

Stratos, one of the world’s largest direct air capture facilities under construction in Texas, uses this approach.

Once CO₂ is trapped in the carbonate or bicarbonate solutions, engineers must separate it out from the liquid so the liquid can return to the chamber to capture more CO₂.

Meanwhile, the captured carbon can be converted into things like plastics, carbonated drinks and even — with further processing — fuel to power homes and potentially airplanes.

But there is a catch. To release the trapped CO₂, companies need to heat the carbonate and bicarbonate solution to at least 900?C (1,652° F), a temperature solar and wind energy is unable to achieve. This step is usually powered by burning fossil-based fuels like natural gas or pure methane.

“If we have to release CO₂ in order to capture CO₂, it defeats the whole purpose of carbon capture,” said Wilson Smith, a professor in the Department of Chemical and Biological Engineering and a fellow of the Renewable and Sustainable Energy Institute at CU Boulder.

Close the loop

Researchers are actively looking for answers. One idea, commonly known as reactive capture, is to apply electricity to the carbonate and bicarbonate solutions, zapping the CO₂ and basic liquid apart in the chamber. In theory, the recycled liquid can then capture more CO₂, forming a closed-loop system.

“Reactive capture is now the buzzword in the field, and researchers proposed that it could help save energy and costs associated with carbon capture. But no one really assessed whether that’s realistic under industrial conditions,” Almajed said.

To do that, the team calculated the mass and energy outputs of the reactive capture units, based on given inputs, to understand how well the overall system would perform. They found that in an industrial setting, electricity would not be able to regenerate the basic liquid to re-capture more CO₂ from the air.

In fact, after five cycles of carbon capture and regeneration, the basic liquid could barely pull any CO₂ out of the air.

The team also suggested a tweak to the reactive capture process by adding a step called electrodialysis. The process splits additional water into acidic and basic ions, helping to maintain the basic liquid’s ability to absorb more CO₂. Electrodialysis can run on renewable electricity, making it a potentially sustainable way to turn captured CO₂ into useful products.

More importantly, electrodialysis can release CO₂ gas, which engineers can use to strengthen concrete.

“To me, turning CO₂ into rocks has to be one of the leading solutions to keep it out of the air over long periods of time,” Smith said. Concrete production is energy-intensive and responsible for 8% of global carbon emissions.

“This is solving multiple problems with one technology,” he said.

The root of the problem

According to the Intergovernmental Panel on Climate Change (IPCC), a team of scientists convened by the United Nations, carbon dioxide removal “is required to achieve global and national targets of net zero CO₂ and greenhouse gas emissions.”

Across the world, more than 20 direct air capture plants are in operation with 130 more currently under construction.

But Smith stresses that while carbon capture may have its place, cutting emissions is still the most critical step needed to avoid the worst outcomes of climate change.

“Imagining Earth as a bathtub, with the running water from the faucet being CO₂. The bathtub is getting full and becoming unlivable. Now, we have two options. We can use a little cup to scoop out the water, cup by cup, or we can turn the faucet off,” Smith said.

“Cutting emissions has to be the priority.”

When it comes to muscles and muscle disorders, the importance of a discovery like this cannot be overstated.

The muscle of muscles

The very core function of life — breathing — is controlled by your skeletal muscles, as is regulation of whole-body metabolism and every movement you make:

• And even blinking

In context

Skeletal muscles are formed during embryonic development by the fusion of hundreds of specialized cells called myoblasts. Adult skeletal muscles maintain regenerative capacity, which is attributed to the presence of muscle stem cells, named satellite cells.

After injury, satellite cells undergo several rounds of proliferation followed by their differentiation into myoblasts. These myoblasts once again fuse with each other and to injured myofibers to accomplish muscle regeneration.

In many muscular disorders, this intrinsic capacity of muscles to regenerate is diminished resulting in the loss of muscle mass and function.

The science

UH researchers found that Inositol-requiring enzyme 1, a key signaling protein, is essential for myoblast fusion during muscle formation and growth.

“During muscle regeneration, IRE1 augments the activity of X-box binding protein 1 which in turn stimulates the gene expression of multiple transmembrane proteins required for myoblast fusion,” reports Ashok Kumar, Else and Philip Hargrove Endowed Professor of pharmacy in the Department of Pharmacological and Pharmaceutical Sciences at the UH College of Pharmacy, in EMBO Reports.

According to researchers, increasing the levels of IRE1 or XBP1 in muscle stem cells outside the body, followed by their injection in patients’ muscle tissues will improve muscle repair and reduce the severity of disease.

“We also found that augmenting the levels of IRE1α or XBP1 in myoblasts leads to the formation of myotubes (muscle cells) having an increased diameter,” said Kumar.

That increase in diameter can be significant.

“Size is very important for muscle. Muscle grows only in size, not in number,” said Aniket Joshi, a graduate student in Kumar’s lab and first author on the article. “Muscular people have larger muscle cells. Larger muscles generally work better- can lift more weight, run and walk faster, and improve overall metabolism of the body and prevent various diseases, such as type II diabetes.”

Flexing their muscles

This new research is not the first flex for Kumar’s team. In 2021, research from Kumar’s lab published in the ELife journal described the role of the IRE1α/XBP1 signaling axis in regeneration of healthy skeletal muscle after acute injury and in models of Duchenne Muscular Dystrophy. In this study, they found that IRE1α/XBP1 signaling axis also plays an important cell autonomous role in satellite cells.

Along with Kumar and Joshi, post-doctoral fellow Meiricris Tomaz da Silva and research assistant professor, Anirban Roy conducted the research in Kumar’s lab. Other authors on the article from the University of Houston include Micah Castillo, Preethi Gunaratne, Mingfu Wu, Yu Liu, and a former post-doctoral fellow in Kumar’s lab Tatiana E. Koike along with Takao Iwawaki of Kanazawa Medical University, Japan.