Green concrete recycling twice the coal ash is built to last

New modelling reveals that low-carbon concrete developed at RMIT University can recycle double the amount of coal ash compared to current standards, halve the amount of cement required and perform exceptionally well over time.

RMIT UNIVERSITY

 

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THE RMIT TEAM: (L-R)) DR YUGUO YU, PROFESSOR SUJEEVA SETUNGE, DR DILAN ROBERT, DR CHAMILA GUNASEKARA, DR DAVID LAW. 

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CREDIT: MICHAEL QUIN, RMIT UNIVERSITY.

New modelling reveals that low-carbon concrete developed at RMIT University can recycle double the amount of coal ash compared to current standards, halve the amount of cement required and perform exceptionally well over time.

More than 1.2 billion tonnes of coal ash were produced by coal-fired power plants in 2022. In Australia, it accounts for nearly a fifth of all waste and will remain abundant for decades to come, even as we shift to renewables.

Meanwhile, cement production makes up 8% of global carbon emissions and demand for concrete – which uses cement as a key ingredient – is growing rapidly.

Addressing both challenges head-on, engineers at RMIT have partnered with AGL's Loy Yang Power Station and the Ash Development Association of Australia to substitute 80% of the cement in concrete with coal fly ash.

RMIT project lead Dr Chamila Gunasekara said this represents a significant advance as existing low-carbon concretes typically have no more than 40% of their cement replaced with fly ash.

"Our addition of nano additives to modify the concrete’s chemistry allows more fly ash to be added without compromising engineering performance,” said Gunasekara, from RMIT’s School of Engineering.

 

Finding new opportunities in overlooked pond ash

Comprehensive lab studies have shown the team’s approach is also capable of harvesting and repurposing lower grade and underutilised ‘pond ash’– taken from coal slurry storage ponds at power plants – with minimal pre-processing.

Large concrete beam prototypes have been created using both fly ash and pond ash and shown to meet Australian Standards for engineering performance and environmental requirements.

“It’s exciting that preliminary results show similar performance with lower-grade pond ash, potentially opening a whole new hugely underutilised resource for cement replacement,” Gunasekara said.

“Compared to fly ash, pond ash is underexploited in construction due to its different characteristics. There are hundreds of megatonnes of ash wastes sitting in dams around Australia, and much more globally.”

“These ash ponds risk becoming an environmental hazard, and the ability to repurpose this ash in construction materials at scale would be a massive win.”

 

New modelling technology shows low-carbon concrete’s long-term resilience

A pilot computer modelling program developed by RMIT in partnership with Hokkaido University' Dr Yogarajah Elakneswaran has now been used to forecast the time-dependent performance of these new concrete mixtures.

According to Dr Yuguo Yu, an expert in virtual computational mechanics at RMIT, a longstanding challenge in the field has been to understand how newly developed materials will stand the test of time.

“We’ve now created a physics-based model to predict how the low-carbon concrete will perform over time, which offers us opportunities to reverse engineer and optimise mixes from numerical insights,” Yu explained.

This pioneering approach – recently unveiled in the prestigious journal Cement and Concrete Research – reveals how various ingredients in the new low-carbon concrete interact over time.

“We’re able to see, for example, how the quick-setting nano additives in the mix act as a performance booster during the early stages of setting, compensating for the large amounts of slower-setting fly ash and pond ash in our mixes,” Gunasekara says.

“The inclusion of ultra-fine nano additives significantly enhances the material by increasing density and compactness.”

This modelling, with its wide applicability to various materials, marks a crucial stride towards digitally assisted simulation in infrastructure design and construction.

By leveraging this technology, the team aims to instil confidence among local councils and communities in adopting novel low-carbon concrete for various applications.

This research was enabled by the ARC Industrial Transformation Research Hub for Transformation of Reclaimed Waste Resources to Engineered Materials and Solutions for a Circular Economy (TREMS). Led by RMIT’s Professor Sujeeva Setunge, TREMS brings together top scientists, researchers and industry experts from nine Australian universities and 36 state, industry, and international partners to minimise landfill waste and repurpose reclaimed materials for construction and advanced manufacturing.

Relevant studies

‘Unified hydration model for multi-blend fly ash cementitious systems of wide-range replacement rates’ is published in Cement and Concrete Research (DOI: 10.1016/j.cemconres.2024.107487)   

‘Sulphate and acid resistance of HVFA concrete incorporating nano silica’ is published in Construction and Building Materials (DOI: 10.1016/j.conbuildmat.2023.132004) 

‘Long term mechanical performance of nano-engineered high volume fly ash concrete’ is published in Journal of Building Engineering (DOI: 10.1016/j.jobe.2021.103168) 

Dr Chamila Gunasekara holds a sample of the low-carbon concrete.

CREDIT

Michael Quin, RMIT University.

JORNAL

Cement and Concrete Research

DOI

10.1016/j.cemconres.2024.107487 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Unified hydration model for multi-blend fly ash cementitious systems of wide-range replacement rates

 

The commercialization of CO2 utilization technology to produce formic acid is imminent

Development of a CCU process for formic acid production with both economic and environmental viability. Expected to expedite the commercialization of CCU through the world's largest-scale demonstration.

NATIONAL RESEARCH COUNCIL OF SCIENCE & TECHNOLOGY

 

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FLOWCHART OF THE PROCESS (ABOVE) FOR PRODUCING FORMIC ACID THROUGH THE CONVERSION OF NEWLY DEVELOPED CARBON DIOXIDE (CO2) USING CARBON CAPTURE & UTILIZATION (CCU), AND PILOT-SCALE PROCESS VERIFICATION DATA (BELOW).

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CREDIT: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY

CCU (Carbon Capture & Utilization), which captures CO2 and converts it into useful compounds, is crucial for rapidly transitioning to a carbon-neutral society. While CCS (Carbon Capture & Storage), which only involves CO2 storage, has entered the initial commercialization stage due to its relatively simple process and low operational costs, CCU has only been explored at the research level due to the complexity of conversion processes and high production costs of compounds.

Dr. Lee Ung's team at the Clean Energy Research Center of the Korea Institute of Science and Technology (KIST, Director Oh Sang Rok) announced the development of a novel CCU process that converts CO2 into formic acid. Formic acid, an organic acid, is a high-value compound used in various industries such as leather, food, and pharmaceuticals. Currently formic acid retains a large market consuming around one million tons annually, which is expected to grow in the future owing to its potential use as a hydrogen carrier. Moreover, it has a higher production efficiency compared to other CCU-based chemicals, as it can be produced from a single CO2 molecule.

The research team selected 1-methylpyrrolidine, which exhibited the highest CO2 conversion rate among various amines mediating formic acid production reactions, and optimized the operating temperature and pressure of the reactor containing a ruthenium (Ru)-based catalyst, thereby increasing the CO2 conversion rate to over twice the current level of 38%. Furthermore, to address the excessive energy consumption and formic acid decomposition issues during CO2 separation from air or exhaust gases and formic acid purification, the team developed a simultaneous capture-conversion process that directly converts CO2 captured within the amine without separating it. As a result, they significantly reduced the formic acid production cost from around $790 per ton to $490 per ton while mitigating CO2 emissions, compared to conventional formic acid production.

To evaluate the commercialization potential of the developed formic acid production process, the research team constructed the world's largest pilot plant capable of producing 10 kg of formic acid per day. Previous CCU studies were conducted on a small scale in laboratories and did not consider the product purification process required for large-scale production. However, the research team developed processes and materials to minimize corrosion and formic acid decomposition, and optimized operating conditions that led to successful production of formic acid with a purity exceeding 92%.

The team plans to complete a 100 kg per day pilot plant by 2025 and conduct process verification, aiming for commercialization by 2030. Success in process verification with the 100 kg pilot plant is expected to enable transportation and sales to demand companies.

Dr. Lee Ung stated, "Through this research, we have confirmed the commercialization potential of our process that converts CO2 to formic acid, which is a huge breakthrough considering that most CCU technologies are being conducted at lab-scale." He further expressed his intention to contribute to achieving the country's carbon neutrality goal by accelerating the commercialization of CCU. .

A depiction of the pilot-scale demonstration process in operation. It consists of a reaction section, separation section, recycling, and vacuum systems, enabling stable continuous operation and enhancing commercialization potential.

CREDIT

Korea Institute of Science and Technology

KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://eng.kist.re.kr/

This research was supported by the Ministry of Science and ICT (Minister Lee Jong-Ho) as part of KIST's major projects and the Carbon-to-X project(2020M3H7A1098271). The research results were published in the latest issue of the international journal "Joule" (IF 39.8, JCR top 0.9%).

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JOURNAL

Joule

DOI

10.1016/j.joule.2024.01.003 

ARTICLE TITLE

Accelerating the net-zero economy with CO2-hydrogenated formic acid production: Process development and pilot plant demonstration

Nanoparticle catalysts convert carbon dioxide to carbon monoxide to make useful compounds

NEWS RELEASE 6-MAY-2024

TSINGHUA UNIVERSITY PRESS

 

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THE IMAGE TO THE LEFT DEPICTS Β-MO2C NANOPARTICLES SUPPORTED ON SIO2 (Β-MO2C/SIO2). THE GRAPH ON THE RIGHT REPRESENTS THE INCREASED CATALYTIC ACTIVITY OF Β-MO2C/SIO2 IN CO PRODUCTION RATE IN THE RWGS REACTION COMPARED TO BULK Β-MO2C, REPRESENTED BY THE BLACK BAR. EACH BAR REPRESENTS A DIFFERENT PERCENTAGE OF MO2C LOADING WEIGHT BASED ON THE MASS OF THE SIO2 SUPPORT. CATALYTIC ACTIVITY FOR THIS DATA WAS MEASURED AT 400°C.

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CREDIT: CARBON FUTURE, TSINGHUA UNIVERSITY PRESS

As a greenhouse gas, carbon dioxide (CO2) contributes to climate change as it accumulates in the atmosphere. One way to reduce the amount of unwanted CO2 in the atmosphere is to convert the gas into a useful carbon product that can be used to generate valuable compounds. A recent study attached nanoparticle of beta phase molybdenum carbide (β-Mo2C) catalysts on a silicon dioxide (SiO2) support to speed the conversion of CO2 into more useful carbon monoxide (CO) gas.

 

CO2 is a very stable molecule, which makes conversion of the greenhouse gas into other molecules challenging. Catalysts can be used in chemical reactions to lower the amount of energy required to form or break chemical bonds and are used in the reverse water gas shift (RWGS) reaction to convert CO2 and hydrogen gas (H2) into CO and water (H2O). Importantly, the CO gas produced by the reaction is called syngas, or synthesis gas, when combined with H2 and can be used as a carbon source to create other important compounds.

 

Traditional catalysts in the RWGS reaction are made from precious metals, including platinum (Pt), palladium (Pd) and gold (Au), limiting the cost efficiency of the reaction. Because of this, new catalyst materials and formation methods are developed to increase the practicality of the RWGS reaction as a means of lowering atmospheric CO2 and generating syngas.

 

In order to address the cost issues of traditional RWGS catalysts, a team of researchers from the University of Illinois in Urbana-Champaign studied the formation and catalytic activity of cheaper nanoparticle β-Mo2C catalysts on a SiO2 support to determine if the lower-cost catalyst could enhance activity levels of β-Mo2C with a silica oxide support in the RWGS reaction.

 

The team published their study in Carbon Future on April 30.

 

“Society is moving towards a carbon-neutral economy. Carbon dioxide is a greenhouse gas, thus any technology that can break down the carbon-oxide bond in this molecule and turn carbon into a value-added chemical could be of great interest. One important C1 chemical is carbon monoxide, which is an essential feedstock to produce a range of products, such as synthetic fuels and vitamin A,” said Hong Yang, Alkire chair professor in the Department of Chemical and Biomolecular Engineering at the University of Illinois at Urbana-Champaign and senior author of the paper.

 

Specifically, the researchers synthesized β-Mo2C nanoparticle catalysts absorbed onto a SiO2 support (β-Mo2C/SiO2). The amorphous structure of the SiO2 support was critical for nanoparticle formation, activity and stability of the β-Mo2C/SiO2 catalyst. The team additionally tested cesium (Ce), magnesium (Mg), titanium (Ti) and aluminum (Al) oxides as potential supports, but catalyst on SiO2 produced the best catalyst formation at the temperature of 650°C.

 

“It appears the disordered nature of amorphous silica, which behaves like glue to catalyst nanoparticles, is a key factor of our success in achieving high metal loading and the corresponding high activity,” said Siying Yu, graduate student in the Department of Chemical and Biomolecular Engineering at the University of Illinois at Urbana-Champaign and co-author of the paper.

 

Importantly, the SiO2 catalyst support structure improves the catalytic activity of β-Mo2C 8-fold compared to bulk β-Mo2C. Even with improved catalytic activity, the β-Mo2C/SiO2 catalyst demonstrated high CO conversion and increased stability compared to bulk β-Mo2C in RWGS reactions.

 

“A major discovery of our work is a new process for producing high metal-loading catalysts made of molybdenum carbide nanoparticles. Such metal carbide catalysts are developed for converting carbon dioxide into carbon oxide at high production rate and selectivity,” said Andrew Kuhn, former graduate student in the Department of Chemical and Biomolecular Engineering at the University of Illinois at Urbana-Champaign and first author of the paper.

 

The researchers performed their study under reaction conditions that favored conversion to CO gas, with a H2:CO2 ratio equal to 1:1. This ratio differs from the more commonly tested ratio of less than 3:1. Reactions were also performed at temperatures between 300 to 600°C. Under these conditions, the team produced more concentrated CO, which is more efficient for downstream compound synthesis.

 

The team sees this research as a launching point for other catalysts that leverage support structures to increase activity. “Our ability to synthesize phase-pure metal carbide nanomaterials at high loading opens the door for the development of new catalysts for the process of CO2 utilization,” said Yang. “I hope through in-depth study of the synthesis-structure-property relationship of this catalyst we will soon be able to uncover new important applications for value-added conversion of CO2 and the sustainable development of our economy.”

 

Other contributors include Rachel Park, Di Gao and Cheng Zhang from the Department of Chemical and Biomolecular Engineering at the University of Illinois at Urbana-Champaign in Urbana, Illinois; and Yuanhui Zhang from the Department of Agricultural and Biological Engineering at the University of Illinois at Urbana-Champaign.

 

This research was supported by the University of Illinois, Urbana-Champaign start-up fund.

 

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About Carbon Future

Carbon Future is an open access, peer-reviewed and international interdisciplinary journal, published by Tsinghua University Press and exclusively available via SciOpen. Carbon Future reports carbon-related materials and processes, including catalysis, energy conversion and storage, as well as low carbon emission process and engineering. Carbon Future will publish Research Articles, Reviews, Minireviews, Highlights, Perspectives, and News and Views from all aspects concerned with carbon. Carbon Future will publish articles that focus on, but not limited to, the following areas: carbon-related or -derived materials, carbon-related catalysis and fundamentals, low carbon-related energy conversion and storage, low carbon emission chemical processes.

About SciOpen 

SciOpen is a professional open access resource for discovery of scientific and technical content published by the Tsinghua University Press and its publishing partners, providing the scholarly publishing community with innovative technology and market-leading capabilities. SciOpen provides end-to-end services across manuscript submission, peer review, content hosting, analytics, and identity management and expert advice to ensure each journal’s development by offering a range of options across all functions as Journal Layout, Production Services, Editorial Services, Marketing and Promotions, Online Functionality, etc. By digitalizing the publishing process, SciOpen widens the reach, deepens the impact, and accelerates the exchange of ideas.

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JOURNAL

Carbon Future

DOI

10.26599/CF.2024.9200011 

ARTICLE TITLE

Valorization of carbon dioxide into C1 product via reverse water gas shift reaction using oxide-supported molybdenum carbides

ARTICLE PUBLICATION DATE

30-Apr-2024

MSHA issues final rule to better protect miners from silica dust exposure

Staff Writer | April 17, 2024 | 3:13 pm Careers Education Suppliers & Equipment USA Coal
Stock image.

The US Department of Labor announced Tuesday that its Mine Safety and Health Administration (MSHA) has issued a final rule to better protect the nation’s miners from health hazards associated with exposure to respirable crystalline silica, also known as silica dust or quartz dust.


The final rule lowers the permissible exposure limit of respirable crystalline silica to 50 micrograms per cubic meter of air for a full-shift exposure, calculated as an 8-hour time-weighted average.

If a miner’s exposure exceeds the limit, the final rule requires mine operators to take immediate corrective actions to come into compliance.

“It is unconscionable that our nation’s miners have worked without adequate protection from silica dust despite it being a known health hazard for decades,” Acting Secretary Julie Su said in a media statement.

“Today, the Department of Labor has taken an important action to finally reduce miners’ exposure to toxic silica dust and protect them from suffering from preventable diseases,” she said.

The rule also requires mine operators to use engineering controls to prevent overexposures to silica dust and use dust samplings and environmental evaluations to monitor exposures.

It also compels metal and non-metal mine operators to establish medical surveillance programs to provide periodic health examinations at no cost to miners. The exams are similar to the medical surveillance programs available to coal miners under existing standards.

The final rule also replaces an outdated standard for respiratory protection with a new standard reflecting the latest advances in respiratory protection and practices. This update will better protect miners against airborne hazards, including silica dust, diesel particulate matter, asbestos and other contaminants.

Inhalation of respirable crystalline silica, a carcinogen, can cause serious lung and other diseases, such as silicosis, lung cancer, progressive massive fibrosis, chronic bronchitis and kidney disease.

Exposure to mixed coal mine dust containing respirable crystalline silica can lead to the development of black lung disease and progressive massive fibrosis. These diseases are irreversible and can be fatal. They are also preventable.

The rule will result in an estimated total of 1,067 lifetime avoided deaths and 3,746 lifetime avoided cases of silica-related illnesses, MSHA estimates.

 

Airy cellulose from a 3D printer

Biodegradable aerogel

SWISS FEDERAL LABORATORIES FOR MATERIALS SCIENCE AND TECHNOLOGY (EMPA)

 

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COMPLEXITY AND LIGHTNESS: EMPA RESEARCHERS HAVE DEVELOPED A 3D PRINTING PROCESS FOR BIODEGRADABLE CELLULOSE AEROGEL.

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CREDIT: EMPA

At first glance, biodegradable materials, inks for 3D printing and aerogels don't seem to have much in common. All three have great potential for the future, however: "green" materials do not pollute the environment, 3D printing can produce complex structures without waste, and ultra-light aerogels are excellent heat insulators. Empa researchers have now succeeded in combining all these advantages in a single material. And their cellulose-based, 3D-printable aerogel can do even more.

The miracle material was created under the leadership of Deeptanshu Sivaraman, Wim Malfait and Shanyu Zhao from Empa's Building Energy Materials and Components laboratory, in collaboration with the Cellulose & Wood Materials and Advanced Analytical Technologies laboratories as well as the Center for X-ray Analytics. Together with other researchers, Zhao and Malfait had already developed a process for printing silica aerogels in 2020. No trivial task: Silica aerogels are foam-like materials, highly open porous and brittle. Before the Empa development, shaping them into complex forms had been pretty much impossible. "It was the logical next step to apply our printing technology to mechanically more robust bio-based aerogels," says Zhao.

The researchers chose the most common biopolymer on Earth as their starting material: cellulose. Various nanoparticles can be obtained from this plant-based material using simple processing steps. Doctoral student Deeptanshu Sivaraman used two types of such nanoparticles – cellulose nanocrystals and cellulose nanofibers – to produce the "ink" for printing the bio-aerogel.

Over 80 percent water

The flow characteristics of the ink are crucial in 3D printing: Tt must be viscous enough in order to hold a three-dimensional shape before solidification. At the same time, however, it should liquefy under pressure so that it can flow through the nozzle. With the combination of nanocrystals and nanofibers, Sivaraman succeeded in doing just that: The long nanofibers give the ink a high viscosity, while the rather short crystals ensure that it has shear thinning effect so that it flows more easily during extrusion.

In total, the ink contains around twelve percent cellulose – and 88 percent water. "We were able to achieve the required properties with cellulose alone, without any additives or fillers," says Sivaraman. This is not only good news for the biodegradability of the final aerogel products, but also for its heat-insulating properties. To turn the ink into an aerogel after printing, the researchers replace the pore solvent water first with ethanol and then with air, all while maintaining shape fidelity. "The less solid matter the ink contains, the more porous the resulting aerogel," explains Zhao.

This high porosity and the small size of the pores make all aerogels extremely effective heat insulators. However, the researchers have identified a unique property in the printed cellulose aerogel: It is anisotropic. This means its strength and thermal conductivity are direction-dependent. "The anisotropy is partly due to the orientation of the nanocellulose fibers and partly due to the printing process itself," says Malfait. This allows the researchers to control in which axis the printed aerogel piece should be particularly stable or particularly insulating. Such precisely crafted insulating components could be used in microelectronics, where heat should only be conducted in a certain direction.

A lot of potential applications in medicine

Although the original research project, which was funded by the Swiss National Science Foundation (SNSF), was primarily interested in thermal insulation, the researchers quickly saw another area of application for their printable bio-aerogel: medicine. As it consists of pure cellulose, the new aerogel is biocompatible with living tissues and cells. Its porous structure is able to absorb drugs and then release them into the body over a long period of time. And 3D printing offers the possibility of producing precise shapes that could, for instance, serve as scaffolds for cell growth or as implants.

A particular advantage is that the printed aerogel can be rehydrated and re-dried several times after the initial drying process without losing its shape or porous structure. In practical applications, this would make the material easier to handle: It could be stored and transported in dry form and only be soaked in water shortly before use. When dry, it is not only light and convenient to handle, but also less susceptible to bacteria – and does not have to be elaborately protected from drying out. "If you want to add active ingredients to the aerogel, this can be done in the final rehydration step immediately before use," says Sivaraman. "Then you don't run the risk of the medication losing its effectiveness over time or if it is stored incorrectly."

The researchers are also working on drug delivery from aerogels in a follow-up project – with less focus on 3D printing for now. Shanyu Zhao is collaborating with researchers from Germany and Spain on aerogels made from other biopolymers, such as alginate and chitosan, derived from algae and chitin respectively. Meanwhile, Wim Malfait wants to further improve the thermal insulation of cellulose aerogels. And Deeptanshu Sivaraman has completed his doctorate and has since joined the Empa spin-off Siloxene AG, which creates new hybrid molecules based on silicon.

The printed objects can be rehydrated and dried multiple times without losing their shape – or they can be made hydrophobic.

CREDIT

Empa

JOURNAL

Advanced Science

DOI

10.1002/advs.202307921 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Additive Manufacturing of Nanocellulose Aerogels with Structure-Oriented Thermal, Mechanical, and Biological Properties

 

Study finds high amounts of silica exposure in previously deployed military veterans

NATIONAL JEWISH HEALTH

Since the conflicts that followed 9/11 in 2001, military veterans deployed to areas in Southwest Asia, Iraq, Afghanistan, and the Horn of Africa have been developing respiratory diseases caused by inhaling particulate matter linked to their deployment locations and job duties. New research published in the International Journal of Environmental Research and Public Health shows levels of silica and other silicates are significantly higher in the lungs of those who have had past deployments compared to normal lung tissue.

“Using elemental analysis of lung tissue, we examined the content of different elements -- silica, titanium, lead and other metals in lung tissue samples from veterans who have deployed since 2001,” said Cecile Rose, MD, MPH, occupational pulmonologist at National Jewish Health and senior author of the published study. “This research gives us greater insight into hazardous military exposures. It is important for our service members, because when they come back from deployment with respiratory symptoms, their symptoms get taken seriously.”

Environmental dust storms, local polluting industries and military operations generate airborne hazards, not only in the line of duty, but also during leisure activities and sleep. Military operations frequently contribute to particulate matter burden due to sources such as exhaust from vehicles, aircraft, and heaters, along with smoke from fires, explosive blasts and burn pits. Some military personnel have jobs that expose them to potentially hazardous airborne vapors, such as dusts, gases or fumes.

For this study, scientists at the U.S. Geological Survey (USGS) worked with National Jewish Health investigators to test the lung tissue samples using sensitive tools.

“The sophisticated equipment and techniques used by USGS were essential to measure the amount and types of dusts that are retained in the lungs following deployment,” said National Jewish Health researcher Lauren Zell-Baran, PhD, MPH. “This was a cutting-edge approach combining the tools of geological science and pulmonary medicine to answer questions about what causes lung inflammation and disease.”

This study underscores the importance of controlling particulate exposures in military occupational settings, particularly dusts containing silica and silicates, to minimize risk for chronic respiratory diseases.

National Jewish Health is the leading respiratory hospital in the nation. Founded 125 years ago as a nonprofit hospital, National Jewish Health today is the only facility in the world dedicated exclusively to groundbreaking medical research and treatment of children and adults with respiratory, cardiac, immune and related disorders. Patients and families come to National Jewish Health from around the world to receive cutting-edge, comprehensive, coordinated care. To learn more, visit the media resources page.

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JOURNAL

International Journal of Environmental Research and Public Health

DOI

10.3390/ijerph21010091 

ARTICLE TITLE

Particle Morphology and Elemental Analysis of Lung Tissue from Post-9/11 Military Personnel with Biopsy-Proven Lung Disease

UMass Amherst-led team creates biofilm-resistant glass for marine environments

The invention prevents biofilm formation by 98% and is poised to help solve a major issue for the U.S. Navy

UNIVERSITY OF MASSACHUSETTS AMHERST

 

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THE GLASS TREATED WITH ULTRAVIOLET RAYS (INSIDE), HAD 98% LESS BIOFILM GROWTH THAN THE UNTREATED GLASS (OUTSIDE).

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CREDIT: LANZARINI-LOPES RESEARCH GROUP

AMHERST, Mass. – A group of researchers led by University of Massachusetts Amherst engineers have created ultraviolet (UV) rays-emitting glass that can reduce 98% of biofilm from growing on surfaces in underwater environments, as reported in the journal Biofilm. 

 

Biofilm is a slimy layer of various types of microorganisms that grows on wet surfaces. “If you look down your sink and touch the inner side of it—that slimy substance is biofilm,” describes Mariana Lanzarini-Lopes, assistant professor of civil and environmental engineering at UMass Amherst, and a corresponding author on the paper.  

 

Biofilm is a significant issue for underwater applications. The United States Navy estimates that biofilms cost its fleet between $180 and $260 million annually. Biofilm growth on all underwater surfaces increases a ship’s drag and subsequent fuel usage, as well as corrosion damage on ships or oceanographic equipment.  

 

Biofilm can also fog up windows used for cameras and other sensing devices that rely on transparency, and transport non-native species across the seas.  

 

Current solutions for dealing with biofilm rely on chemical agents like biocidal coatings to kill the organisms or nonstick coatings to prevent biofilms from attaching in the first place. However, these methods can have negative effects on the ecosystem and only last for a short duration.  

 

As an alternative to these chemical methods the UMass Amherst team, with funding from the U.S. Office of Naval Research (ONR), developed biofilm-resistant glass using UVC radiation, the shortest and most effective at disinfecting wavelength of UV radiation. Lopes’s lab has already demonstrated that UV side-emitting optical fiber can distribute UVC radiation in small channels, like medical equipment (i.e. endoscopes, catheters and respirators), home devices (coffee makers and refrigerators) and water storage/distribution systems (pipes, bladders, membranes) to inactivate pathogenic organisms and prevent bacteria growth on surfaces. 

 

“A lot of people know about UV for disinfecting surfaces, air and water,” says Lopes.  “People started using it a lot more especially because it was really effective for disinfection of the SARS-CoV-2 virus.”  

 

However, in an underwater environment, it’s not as simple as shining UV light onto glass. “We cannot use traditional light sources to distribute light evenly on the surface,” for several reasons, says Leila Alidokht, postdoctoral research associate in Lopes’s lab and lead study author. Light becomes weaker as it moves away from the source, making it difficult to cover large surface areas. The UV waves can also be disrupted by how murky the surrounding water. 

 

Uneven distribution of the UV light gives biofilm-forming microorganisms a foothold and leaves the whole surface vulnerable: “If the biofilm can attach to a part of the surface, it can spread to other parts,” she adds. 

 

The team’s solution is a silica-nanoparticle coating on the glass. “The UV LED is connected from the cross-section of the glass,” Alidokht describes. “As UV enters the glass, we scatter the UV from inside of the glass to the outside,” using these light-scattering nanoparticles. The silica does not absorb the UV rays. The waves continue to bounce off the nanoparticles and through the glass interior which enables an evenly “glowing” glass surface.  

 

To test it, the researchers, in partnership with Florida Tech and the Navy, submerged this UV-emitting glass in the waters of Port Canaveral, Florida for 20 days. Compared to untreated glass, this glass reduced visible biofilm growth by 98%. 

“Contrary to external UV irradiation technique, UV-emitting glass inhibits biofilm formation directly at the surface of interest—the surface itself serves as a UVC source,” says Alidokht. 

 

She is excited that this discovery opens the door for diverse disinfection applications. “The developed technology can be used for disinfection of transparent surfaces such as windows of ships, flotation spheres and moored buoys, camera lenses and sensors for oceanographical, agricultural and water treatment applications,” she says. 

 

The team has received a provisional patent for their discovery.  

 

Now that the team has proven that this glass effectively resists biofilm formation (known as biofouling), they are excited to optimize their discovery: testing long-term applications, assessing any effects on the environment and creating larger surface areas. 

 

Another future avenue of exploration: “We’re also trying to prevent biofilm on camera lenses,” adds Lopes. “The maininhibitor of the length of time for deployment [of underwater cameras] is biofouling, so as long as you can decrease the rate of biofouling, you can increase how long you deploy all this optical equipment.”

Because the glass has a silica nanoparticle coating, the UV waves bounce through the glass interior which enables an evenly “glowing” glass surface.

CREDIT

Lanzarini-Lopes research group

Lanzarini-Lopes (center) with Alidokht (right) and graduate research assistant, Athira Haridas (left) 

CREDIT

Lanzarini-Lopes research group

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JOURNAL

Biofilm

DOI

10.1016/j.bioflm.2024.100186 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

UV emitting glass: A promising strategy for biofilm inhibition on transparent surfaces

ARTICLE PUBLICATION DATE

28-Feb-2024

COI STATEMENT

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Mariana Lanzarini-Lopes reports a relationship with Optical Waters that includes: board membership, equity or stocks, and funding grants. Katrina Fitzpatrick reports a relationship with Optical Waters that includes: board membership, equity or stocks, and funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Sunrise to sunset, new window coating blocks heat — not view

UNIVERSITY OF NOTRE DAME

 

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RESEARCHERS AT THE UNIVERSITY OF NOTRE DAME HAVE DEVELOPED A NEW WINDOW COATING TO BLOCK HEAT-GENERATING ULTRAVIOLET AND INFRARED LIGHT AND ALLOW FOR VISIBLE LIGHT, REGARDLESS OF THE SUN’S ANGLE.

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CREDIT: UNIVERSITY OF NOTRE DAME

Windows welcome light into interior spaces, but they also bring in unwanted heat. A new window coating blocks heat-generating ultraviolet and infrared light and lets through visible light, regardless of the sun’s angle. The coating can be incorporated onto existing windows or automobiles and can reduce air-conditioning cooling costs by more than one-third in hot climates.  

“The angle between the sunshine and your window is always changing,” said Tengfei Luo, the Dorini Family Professor for Energy Studies at the University of Notre Dame and the lead of the study. “Our coating maintains functionality and efficiency whatever the sun’s position in the sky.”

Window coatings used in many recent studies are optimized for light that enters a room at a 90-degree angle. Yet at noon, often the hottest time of the day, the sun’s rays enter vertically installed windows at oblique angles.

Luo and his postdoctoral associate Seongmin Kim previously fabricated a transparent window coating by stacking ultra-thin layers of silica, alumina and titanium oxide on a glass base. A micrometer-thick silicon polymer was added to enhance the structure’s cooling power by reflecting thermal radiation through the atmospheric window and into outer space.

Additional optimization of the order of the layers was necessary to ensure the coating would accommodate multiple angles of solar light. However, a trial-and-error approach was not practical, given the immense number of possible combinations, Luo said.

To shuffle the layers into an optimal configuration — one that maximized the transmission of visible light while minimizing the passage of heat-producing wavelengths — the team used quantum computing, or more specifically, quantum annealing, and validated their results experimentally.

Their model produced a coating that both maintained transparency and reduced temperature by 5.4 to 7.2 degrees Celsius in a model room, even when light was transmitted in a broad range of angles. The lab’s results were recently published in Cell Reports Physical Science.  

“Like polarized sunglasses, our coating lessens the intensity of incoming light, but, unlike sunglasses, our coating remains clear and effective even when you tilt it at different angles,” Luo said.

The active learning and quantum computing scheme developed to create this coating can be used to design of a broad range of materials with complex properties.

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JOURNAL

Cell Reports Physical Science

DOI

10.1016/j.xcrp.2024.101847 

ARTICLE TITLE

Wide-Angle Spectral Filter for Energy-Saving Windows Designed by Quantum Annealing-Enhanced Active Learning

Researchers use smartphone screen to create 3D layered holographic images

Full-color 3D display method holds promise for augmented and virtual reality

OPTICA

 

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RESEARCHERS DEVELOPED A 3D FULL-COLOR DISPLAY METHOD THAT USES A SMARTPHONE SCREEN, RATHER THAN A LASER, TO CREATE HOLOGRAPHIC IMAGES. SHOWN ARE THEIR EXPERIMENTAL RESULTS, IN WHICH A CONTINUOUS TRANSITION FROM THE FIRST LAYER TO THE SECOND LAYER IS OBSERVABLE.

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CREDIT: RYOICHI HORISAKI, THE UNIVERSITY OF TOKYO

WASHINGTON — Researchers have developed a 3D full-color display method that uses a smartphone screen, rather than a laser, to create holographic images. With further development, the new approach could be useful for augmented or virtual reality displays.

Whether augmented and virtual reality displays are being used for gaming, education or other applications, incorporating 3D displays can create a more realistic and interactive user experience.

“Although holography techniques can create a very real-looking 3D representation of objects, traditional approaches aren’t practical because they rely on laser sources,” said research team leader Ryoichi Horisaki, from The University of Tokyo in Japan. “Lasers emit coherent light that is easy to control, but they make the system complex, expensive and potentially harmful to the eyes.”

In the Optica Publishing Group journal Optics Letters, the researchers describe their new method, which is based on computer-generated holography (CGH). Thanks to a new algorithm they developed, they were able to use only an iPhone and an optical component called a spatial light modulator to reproduce a 3D color image that consisted of two holographic layers.

“We believe that this method could eventually be useful for minimizing the optics, reducing costs and decreasing the potential harm to eyes in future visual interfaces and 3D display applications,” said Otoya Shigematsu, the paper’s first author. “More specifically, it has the potential to enhance the performance of near-eye displays, such as the ones being used in high-end virtual reality headsets.”

A more practical approach

Although CGH uses algorithms to produce images, the coherent light from a laser is typically required to display these holographic images. In a previous study, the researchers showed that spatiotemporally incoherent light emitted from a white chip-on-board light-emitting diode could be used for CGH. However, this setup required two spatial light modulators — devices that control the wavefronts of light — which is impractical because of their expense.

In the new study, the researchers developed a less expensive and more practical incoherent CGH method. “This work aligns with our laboratory’s focus on computational imaging, a research field dedicated to innovating optical imaging systems by integrating optics with information science,” said Horisaki. “We focus on minimizing optical components and eliminating impractical requirements in conventional optical systems.”

The new approach passes light from the screen through a spatial light modulator, which presents multiple layers of a full-color 3D image. Although this may seem simple, it required carefully modeling the incoherent light propagation process from the screen and then using this information to develop a new algorithm that coordinated the light coming from the device screen with a single spatial light modulator.

Holographic images from a smartphone

“Holographic displays that use low-coherence light could enable realistic 3D displays while potentially reducing costs and complexity,” said Shigematsu. “Although several groups, including ours, have demonstrated holographic displays using low-coherence light, we took this concept to the extreme by using a smartphone display.”

To demonstrate the new method, the researchers created a two-layer optical reproduction of a full-color 3D image by displaying one holographic layer on the screen of an iPhone 14 Pro and a second layer on a spatial light modulator. The resulting image measured a few millimeters on each side.

The researchers are now working to improve the technology so that it can display larger 3D images with more layers. Additional layers would make images look more realistic by improving spatial resolution and allowing objects to appear at several different depths, or distances, from the viewer.

Paper: O. Shigematsu, M. Naruse, R. Horisaki, “Computer-generated holography with ordinary display,” Opt. Lett., 49, 8 (2024).
DOI: doi.org/10.1364/OL.516005

First author Otoya Shigematsu is shown in the laboratory with the optical experiment setup used for the work.

CREDIT

Ryoichi Horisaki, The University of Tokyo

About Optics Letters

Optics Letters offers rapid dissemination of new results in all areas of optical science with short, original, peer-reviewed communications. Optics Letters accepts papers that are noteworthy to a substantial part of the optics community. Published by Optica Publishing Group and led by Editor-in-Chief Miguel Alonso, Institut Fresnel, École Centrale de Marseille and Aix-Marseille Université, France, University of Rochester, USA. For more information, visit Optics Letters.

 

About Optica Publishing Group

Optica Publishing Group is a division of Optica, Advancing Optics and Photonics Worldwide. It publishes the largest collection of peer-reviewed content in optics and photonics, including 18 prestigious journals, the society’s flagship member magazine, and papers from more than 835 conferences, including 6,500+ associated videos. With over 400,000 journal articles, conference papers and videos to search, discover and access, Optica Publishing Group represents the full range of research in the field from around the globe.

JOURNAL

Optics Letters

DOI

10.1364/OL.516005 

ARTICLE TITLE

Computer-generated holography with ordinary display

ARTICLE PUBLICATION DATE

2-Apr-2024