The waste product which could help mitigate climate change

A product made from urban, agriculture and forestry waste has the added benefit of reducing the carbon footprint of modern farming, an international review involving UNSW has found.

Visiting Professor in the School of Materials Science and Engineering at UNSW Science, Stephen Joseph, says the study published in GCB Bioenergy provides strong evidence that biochar can contribute to climate change mitigation.

"Biochar can draw down carbon from the atmosphere into the soil and store it for hundreds to thousands of years," the lead author says."This study also found that biochar helps build organic carbon in soil by up to 20 per cent (average 3.8 per cent) and can reduce nitrous oxide emissions from soil by 12 to 50 per cent, which increases the climate change mitigation benefits of biochar."

The findings are supported by the Intergovernmental Panel on Climate Change's recent Special Report on Climate Change and Land, which estimated there was important climate change mitigation potential available through biochar. "The intergovernmental panel found that globally, biochar could mitigate between 300 million to 660 million tonnes of carbon dioxide per year by 2050," Prof. Joseph says. "Compare that to Australia's emissions last year -- an estimated 499 million tonnes of carbon dioxide -- and you can see that biochar can absorb a lot of emissions. We just need a will to develop and use it."

Biochar is the product of heating biomass residues such as wood chips, animal manures, sludges, compost and green waste, in an oxygen-starved environment -- a process called pyrolysis. The result is stable charcoal which can cut greenhouse emissions, while boosting soil fertility. The GCB Bioenergystudy reviewed approximately 300 papers including 33 meta-analyses that examined many of the 14,000 biochar studies that have been published over the last 20 years.

"It found average crop yields increased from 10 to 42 per cent, concentrations of heavy metals in plant tissue were reduced by 17 to 39 per cent and phosphorus availability to plants increased too," Prof. Joseph says. "Biochar helps plants resist environmental stresses, such as diseases, and helps plants tolerate toxic metals, water stress and organic compounds such as the herbicide atrazine." The study details for the first time how biochar improves the root zone of a plant. In the first three weeks, as biochar reacts with the soil it can stimulate seed germination and seedling growth. During the next six months, reactive surfaces are created on biochar particles, improving nutrient supply to plants. After three to six months, biochar starts to 'age' in the soil and forms microaggregates that protect organic matter from decomposition.

Prof. Joseph says the study found the greatest responses to biochar were in acidic and sandy soils where biochar had been applied together with fertiliser. "We found the positive effects of biochar were dose dependent and also dependent on matching the properties of the biochar to soil constraints and plant nutrient requirements," Prof. Joseph says. "Plants, particularly in low-nutrient, acidic soils common in the tropics and humid subtropics, such as the north coast of NSW and Queensland, could significantly benefit from biochar. "Sandy soils in Western Australia, Victoria and South Australia, particularly in dryland regions increasingly affected by drought under climate change, would also greatly benefit."

Prof. Joseph AM is an expert in producing engineered stable biochar from agriculture, urban and forestry residues. He has been researching the benefits of biochar in promoting healthy soils and addressing climate change since he was introduced to it by Indigenous Australians in the seventies. He says biochar has been used for production of crops and for maintaining healthy soils by Indigenous peoples in Australia, Latin America (especially in the Amazon basin) and Africa for many hundreds of years.

Biochar has also been recorded in the 17th Century as a feed supplement for animals. But while Australian researchers have studied biochar since 2005, it has been relatively slow to take off as a commercial product, with Australia producing around 5000 tonnes a year. "This is in part due to the small number of large-scale demonstration programs that have been funded, as well as farmers' and government advisors' lack of knowledge about biochar, regulatory hurdles, and lack of venture capital and young entrepreneurs to fund and build biochar businesses," Prof. Joseph says.

In comparison, the US is producing about 50,000 tonnes a year, while China is producing more than 500,000 tonnes a year. Prof. Joseph, who has received an Order of Australia for his work in renewable energy and biochar, says to enable widespread adoption of biochar, it needs to be readily integrated with farming operations and be demonstrated to be economically viable. "We've done the science, what we don't have is enough resources to educate and train people, to establish demonstrations so farmers can see the benefits of using biochar, to develop this new industry," he says.

However this is slowly changing as large corporations are purchasing carbon dioxide reduction certificates (CORC's) to offset their emissions, which is boosting the profile of biochar in Australia. Biochar has potential in a range of applications. Prof. Joseph co-authored a recent study in International Materials Reviews which detailed the less well-known uses of biochar, such as a construction material, to reduce toxins in soil, grow microorganisms, in animal feed and soil remediation. UNSW has a collaborative grant with a company and a university in Norway to develop a biochar based anti-microbial coating to kill pathogens in water and find use in air filtration systems, he says.

Read more at Science Daily

How landscapes of fear affect the songbirds in our backyards

A team of researchers headquartered at the University of Massachusetts Amherst has recently discovered that fear plays an important, unrecognized role in the underdevelopment, and increased vulnerability, of backyard songbirds.

Scientists have long known that urban songbirds face a host of increased challenges, from habitat loss to altered food sources and a larger population of predators, such as skunks, rats, squirrels and, especially, house cats, compared to their rural cousins. In particular, urban nestlings weigh significantly less than those born in the country and have a decreased chance of surviving to adulthood, as a result. New research, published in the journal Ecosphere, helps to tease out exactly why.

Part of the difficulty in figuring out why urban nestlings struggle is due to what biologists call the "predation paradox:" though there are increased numbers of predators in urban areas, there is actually a lower per-capita rate of predation. "The key," says Aaron Grade, the paper's lead author who completed this research as a graduate student in UMass Amherst's program in organismic and evolutionary biology, "has been hiding in plain sight. We haven't been paying enough attention to fear itself."

To arrive at this conclusion, Grade, along with his co-authors Susannah B. Lerman, research ecologist at the USDA Forest Service Northern Research Station; and Paige S. Warren, professor in the department of environmental conservation at UMass Amherst; built 38 nest boxes for house wrens and placed them in participants' backyards. The participants lived in a variety of landscapes, all in the Connecticut River Valley of Massachusetts, from the urban (Springfield, with a population density of 4,775 people per square mile), to low-density suburban (Amherst, 1,445 people per square mile) to the rural (Whately, 72 people per square mile).

Grade and his colleagues then played the cries of screech owls and Cooper's hawks, both of which feed upon house wrens in Massachusetts, from speakers installed in each participant's yard. "The participants were wonderful," says Grade. "They put up with this noise in their backyards and were very invested in the experiment." The nestlings in each box were then weighed every three days until they left the nest.

The authors discovered that, due to a variety of 'urban effects,' including availability of food, habitat loss and predation, urban nestlings all weighed about 10% less than the rural nestlings -- an expected finding that is consistent with previous studies showing the effects of urban development on wildlife. But the authors also discovered that all the nestlings, both rural and urban, subjected to the owl and hawk cries saw a 10% decrease in weight as well.

"This is a largely unexplored component of human/wildlife interaction," says Grade. "Birds are very in-tune with what's going on, and if they see, or in this case hear, a predator, they'll change their behavior." For instance, the parent birds might spend less time finding food for their nestlings to avoid predation. "These landscapes of fear," says Grade, "can have a greater effect on behavior and survival than the actual predator itself."

In general, hobbyist birders should avoid using recordings of predators because they can cause unintended responses and undue stress in birds, as Grade's research shows. These experiments were carried out with approval by the UMass Institutional Animal Care and Use Committee and followed best practices for playback experiments to reduce any potential harm.

Read more at Science Daily

Why is this weird, metallic star hurtling out of the Milky Way?

About 2,000 light-years away from Earth, there is a star catapulting toward the edge of the Milky Way. This particular star, known as LP 40?365, is one of a unique breed of fast-moving stars -- remnant pieces of massive white dwarf stars -- that have survived in chunks after a gigantic stellar explosion.

"This star is moving so fast that it's almost certainly leaving the galaxy…[it's] moving almost two million miles an hour," says JJ Hermes, Boston University College of Arts & Sciences assistant professor of astronomy. But why is this flying object speeding out of the Milky Way? Because it's a piece of shrapnel from a past explosion -- a cosmic event known as a supernova -- that's still being propelled forward.

"To have gone through partial detonation and still survive is very cool and unique, and it's only in the last few years that we've started to think this kind of star could exist," says Odelia Putterman, a former BU student who has worked in Hermes' lab.

In a new paper published in The Astrophysical Journal Letters, Hermes and Putterman uncover new observations about this leftover "star shrapnel" that gives insight to other stars with similar catastrophic pasts.

Putterman and Hermes analyzed data from NASA's Hubble Space Telescope and Transiting Exoplanet Survey Satellite (TESS), which surveys the sky and collects light information on stars near and far. By looking at various kinds of light data from both telescopes, the researchers and their collaborators found that LP 40?365 is not only being hurled out of the galaxy, but based on the brightness patterns in the data, is also rotating on its way out.

"The star is basically being slingshotted from the explosion, and we're [observing] its rotation on its way out," says Putterman, who is second author on the paper.

"We dug a little deeper to figure out why that star [was repeatedly] getting brighter and fainter, and the simplest explanation is that we're seeing something at [its] surface rotate in and out of view every nine hours," suggesting its rotation rate, Hermes says. All stars rotate -- even our sun slowly rotates on its axis every 27 days. But for a star fragment that's survived a supernova, nine hours is considered relatively slow.

Supernovas occur when a white dwarf gets too massive to support itself, eventually triggering a cosmic detonation of energy. Finding the rotation rate of a star like LP 40?365 after a supernova can lend clues into the original two-star system it came from. It's common in the universe for stars to come in close pairs, including white dwarfs, which are highly dense stars that form toward the end of a star's life. If one white dwarf gives too much mass to the other, the star being dumped on can self-destruct, resulting in a supernova. Supernovas are commonplace in the galaxy and can happen in many different ways, according to the researchers, but they are usually very hard to see. This makes it hard to know which star did the imploding and which star dumped too much mass onto its star partner.

Based on LP 40?365's relatively slow rotation rate, Hermes and Putterman feel more confident that it is shrapnel from the star that self-destructed after being fed too much mass by its partner, when they were once orbiting each other at high speed. Because the stars were orbiting each other so quickly and closely, the explosion slingshotted both stars, and now we only see LP 40-365.

"This [paper] adds one more layer of knowledge into what role these stars played when the supernova occurred," and what can happen after the explosion, Putterman says. "By understanding what's happening with this particular star, we can start to understand what's happening with many other similar stars that came from a similar situation."

Read more at Science Daily

Exercise improves health through changes on DNA

While it is widely known that regular physical exercise decreases the risk of virtually all chronic illnesses, the mechanisms at play are not fully known. Now scientists at the University of Copenhagen have discovered that the beneficial effects of physical exercise may in part result from changes to the structure of our DNA. These changes are referred as 'epigenetic'.

DNA is the molecular instruction manual found in all our cells. Some sections of our DNA are genes, which are instructions for building proteins -- the body's building blocks -- while other sections are called enhancers that regulate which genes are switched on or off, when, and in which tissue. The scientists found, for the first time, that exercise rewires the enhancers in regions of our DNA that are known to be associated with the risk to develop disease.

"Our findings provide a mechanism for the known beneficial effects of exercise. By connecting each enhancer with a gene, we further provide a list of direct targets that could mediate this effect," says Professor Romain Barrès from the Novo Nordisk Foundation Center for Basic Metabolic Research, the senior author of the research, which was published in Molecular Metabolism.

Exercise improves health of organs including the brain

The team of scientists hypothesized that endurance exercise training remodels the activity of gene enhancers in skeletal muscle. They recruited healthy young men and put them through a six-week endurance exercise program. The scientists collected a biopsy of their thigh muscle before and after the exercise intervention and examined if changes in the epigenetic signature of their DNA occurred after training.

The scientists discovered that after completing the endurance training program, the structure of many enhancers in the skeletal muscle of the young men had been altered. By connecting the enhancers to genetic databases, they discovered that many of the regulated enhancers have already been identified as hotspots of genetic variation between individuals -- hotspots that have been associated with human disease.

The scientists speculate that the beneficial effects of exercise on organs distant from muscle, like the brain, may largely be mediated by regulating the secretion of muscle factors. In particular, they found that exercise remodels enhancer activity in skeletal muscle that are linked to cognitive abilities, which opens for the identification of exercise training-induced secreted muscle factors targeting the brain.

Read more at Science Daily

Learning foreign languages can affect the processing of music in the brain

Research has shown that a music-related hobby boosts language skills and affects the processing of speech in the brain. According to a new study, the reverse also happens -- learning foreign languages can affect the processing of music in the brain.

Research Director Mari Tervaniemi from the University of Helsinki's Faculty of Educational Sciences investigated, in cooperation with researchers from the Beijing Normal University (BNU) and the University of Turku, the link in the brain between language acquisition and music processing in Chinese elementary school pupils aged 8-11 by monitoring, for one school year, children who attended a music training programme and a similar programme for the English language. Brain responses associated with auditory processing were measured in the children before and after the programmes. Tervaniemi compared the results to those of children who attended other training programmes.

"The results demonstrated that both the music and the language programme had an impact on the neural processing of auditory signals," Tervaniemi says.

Learning achievements extend from language acquisition to music

Surprisingly, attendance in the English training programme enhanced the processing of musically relevant sounds, particularly in terms of pitch processing.

"A possible explanation for the finding is the language background of the children, as understanding Chinese, which is a tonal language, is largely based on the perception of pitch, which potentially equipped the study subjects with the ability to utilise precisely that trait when learning new things. That's why attending the language training programme facilitated the early neural auditory processes more than the musical training."

Tervaniemi says that the results support the notion that musical and linguistic brain functions are closely linked in the developing brain. Both music and language acquisition modulate auditory perception. However, whether they produce similar or different results in the developing brain of school-age children has not been systematically investigated in prior studies.

At the beginning of the training programmes, the number of children studied using electroencephalogram (EEG) recordings was 120, of whom more than 80 also took part in EEG recordings a year later, after the programme.

In the music training, the children had the opportunity to sing a lot: they were taught to sing from both hand signs and sheet music. The language training programme emphasised the combination of spoken and written English, that is, simultaneous learning. At the same time, the English language employs an orthography that is different from Chinese. The one-hour programme sessions were held twice a week after school on school premises throughout the school year, with roughly 20 children and two teachers attending at a time.

Read more at Science Daily

New study details enzyme that allows coronavirus to resist antiviral medications

The coronavirus that causes COVID-19 has demonstrated a stubborn ability to resist most nucleoside antiviral treatments, but a new study led by an Iowa State University scientist could help to overcome the virus's defenses.

The study, published recently in the peer-reviewed journal Science, details the structure of a critical enzyme present in SARS-CoV-2, the coronavirus that causes COVID-19. This enzyme, known as the proofreading exoribonuclease (or ExoN), removes nucleoside antiviral medications from the virus's RNA, rendering most nucleoside analogs-based antiviral treatments ineffective. The new study presents the atomic structures of the ExoN enzyme, which could lead to the development of new methods for deactivating the enzyme and opening the door to better treatments for patients suffering from COVID-19.

"If we could find a way to inhibit this enzyme, maybe we can achieve better results to kill the virus with existing nucleoside antiviral treatments. Understanding this structure and the molecular details of how ExoN works can help guide further development of antivirals," said Yang Yang, lead author of the study and assistant professor in the Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology at Iowa State University.

SARS-CoV-2 is an RNA virus, which means its genetic material is composed of ribonucleic acid. When the virus replicates, it must synthesize RNA. But the virus's genome is unusually large when compared to other RNA viruses, which creates a relatively high likelihood that errors arise during RNA synthesis. These errors take the form of mismatched nucleotides, and too many errors can prevent the virus from propagating.

But the ExoN enzyme acts as a proofreader, recognizing mismatches in the virus RNA and correcting errors that occur during RNA synthesis, Yang said. The enzyme is present only in coronaviruses and a few other closely related virus families, he said.

The same process that eliminates replication errors also eliminates antiviral agents delivered by the treatments commonly used to fight other RNA viruses, such as HIV, HCV and Ebola virus, which partially explains why SARS-CoV-2 has proven so difficult to treat, Yang said.

But Yang and his colleagues utilized cryogenic electron microscopy, a technique in which samples are flash cooled to cryogenic temperatures in vitreous ice to preserve their native structures, to detail the structure of the enzyme. Understanding that structure could allow for the development of molecules that bind to the enzyme and disable it. Yang said that's the next step for his laboratory and his colleagues. Finding such a molecule could make the virus more susceptible to newly developed antivirals, Yang said. Or, it could allow for the optimization of current antivirals, such as Remdesivir.

Read more at Science Daily

Astronomers probe layer-cake structure of brown dwarf’s atmosphere

Maunakea, Hawaii -- Jupiter may be the bully planet of our solar system because it's the most massive planet, but it's actually a runt compared to many of the giant planets found around other stars.

These alien worlds, called super-Jupiters, weigh up to 13 times Jupiter's mass. Astronomers have analyzed the composition of some of these monsters, but it has been difficult to study their atmospheres in detail because these gas giants get lost in the glare of their parent stars.

Researchers, however, have a substitute: the atmospheres of brown dwarfs, so-called failed stars that are up to 80 times Jupiter's mass. These hefty objects form out of a collapsing cloud of gas, as stars do, but lack the mass to become hot enough to sustain nuclear fusion in their cores, which powers stars.

Instead, brown dwarfs share a kinship with super-Jupiters. Both types of objects have similar temperatures and are extremely massive. They also have complex, varied atmospheres. The only difference, astronomers think, is their pedigree. Super-Jupiters form around stars; brown dwarfs often form in isolation.

A team of astronomers, led by Elena Manjavacas of the Space Telescope Science Institute in Baltimore, Maryland, has tested a new way to peer through the cloud layers of these nomadic objects. The researchers used an instrument at W. M. Keck Observatory on Maunakea in Hawaii to study in near-infrared light the colors and brightness variations of the layer-cake cloud structure in the nearby, free-floating brown dwarf known as 2MASS J22081363+2921215.

The Keck Observatory instrument, called the Multi-Object Spectrograph for Infrared Exploration (MOSFIRE), also analyzed the spectral fingerprints of various chemical elements contained in the clouds and how they change with time. This is the first time astronomers have used MOSFIRE in this type of study.

These measurements offered Manjavacas a holistic view of the brown dwarf's atmospheric clouds, providing more detail than previous observations of this object. Pioneered by Hubble observations, this technique is difficult for ground-based telescopes to do because of contamination from Earth's atmosphere, which absorbs certain infrared wavelengths. This absorption rate changes due to the weather.

"The only way to do this from the ground is by using Keck's high-resolution MOSFIRE instrument because it allows us to observe multiple stars simultaneously with our brown dwarf," said Manjavacas, a former staff astronomer at Keck Observatory and the lead author of the study. "This allows us to correct for the contamination introduced by the Earth's atmosphere and measure the true signal from the brown dwarf with good precision. So, these observations are a proof-of-concept that MOSFIRE can do these types of studies of brown dwarf atmospheres."

She decided to study this particular brown dwarf because it is very young and therefore extremely bright. It has not cooled off yet. Its mass and temperature are similar to those of the nearby giant exoplanet Beta Pictoris b, discovered in 2008 near-infrared images taken by the European Southern Observatory's Very Large Telescope in northern Chile.

"We don't have the ability yet with current technology to analyze in detail the atmosphere of Beta Pictoris b," Manjavacas said. "So, we're using our study of this brown dwarf's atmosphere as a proxy to get an idea of what the exoplanet's clouds might look like at different heights of its atmosphere."

Both the brown dwarf and Beta Pictoris b are young, so they radiate heat strongly in the near-infrared. They are both members of a flock of stars and sub-stellar objects called the Beta Pictoris moving group, which shares the same origin and a common motion through space. The group, which is about 33 million years old, is the closest grouping of young stars to Earth. It is located roughly 115 light-years away.

While they're cooler than bona fide stars, brown dwarfs are still extremely hot. The brown dwarf in Manjavacas' study is a sizzling 2,780 degrees Fahrenheit (1,527 degrees Celsius).

The giant object is about 12 times heavier than Jupiter. As a young body, it is spinning incredibly fast, completing a rotation every 3.5 hours, compared to Jupiter's 10-hour rotation period. So, clouds are whipping around the planet, creating a dynamic, turbulent atmosphere.

Keck Observatory's MOSFIRE instrument stared at the brown dwarf for 2.5 hours, watching how the light filtering up through the atmosphere from the dwarf's hot interior brightens and dims over time. Bright spots that appeared on the rotating object indicate regions where researchers can see deeper into the atmosphere, where it is hotter. Infrared wavelengths allow astronomers to peer deeper into the atmosphere. The observations suggest the brown dwarf has a mottled atmosphere with scattered clouds. If viewed close-up, the planet might resemble a carved Halloween pumpkin, with light escaping from the hot interior.

Its spectrum reveals clouds of hot sand grains and other exotic elements. Potassium iodide traces the object's upper atmosphere, which also includes magnesium silicate clouds. Moving down in the atmosphere is a layer of sodium iodide and magnesium silicate clouds. The final layer consists of aluminum oxide clouds. The atmosphere's total depth is 446 miles (718 kilometers). The elements detected represent a typical part of the composition of brown dwarf atmospheres, Manjavacas said.

She and her team used computer models of brown dwarf atmospheres to determine the location of the chemical compounds in each cloud layer.

Read more at Science Daily

Oxygen spike coincided with ancient global extinction

Two hundred fifty-two million years ago, much of life on planet Earth was dying.

In an event that marked the end of the Permian period, more than 96 percent of the planet's marine species and 70 percent of its terrestrial life suddenly went extinct. It was the largest extinction in Earth's history.

Now Florida State University researchers have found that the extinction coincided with a sudden spike and subsequent drop in the ocean's oxygen content. Their findings were published in Nature Geoscience.

"There's previous work that's been done that shows the environment becoming less oxygenated leading into the extinction event, but it has been hypothesized as a gradual change," said lead author and FSU graduate research assistant Sean Newby. "We were surprised to see this really rapid oxygenation event coinciding with the start of the extinction and then a return to reducing conditions."

Scientists have previously seen a gradual decrease in oxygen during this extinction, but the rapid oxygen increase at the beginning of the extinction was a new finding. The researchers think the oxygenation occurred over a few tens of thousands of years, a very brief period on the scale of the millions of years of the Earth's geological history.

"For the geological record, that's practically instantaneous," Newby said. "And then you can of course compare that to modern, human-induced climate change, where we're having huge, rapid changes on fractions of the time compared to this mass extinction."

The exact cause of this spike in ocean oxygenation is unknown, but the researchers hypothesized that the continual eruption of at least several hundred thousand years of a massive volcanic region led to a brief cooling and the sudden marine oxygenation spike and subsequent crash.

Although ancient marine oxygen levels were on a downward trend ahead of the spike and remained low afterward, it's the geologically rapid shift back and forth and long-term oxygen deficiency that seemed to be more detrimental to life than the gradual decrease. The carbon dioxide released during that volcanic eruption caused the Earth's atmosphere to warm, which lowered oxygen in the oceans and caused the oceans to become relatively inhospitable for millions of years.

It is impossible to directly measure ancient marine or atmospheric oxygen levels, so the research team instead measured thallium isotopes, which indirectly provided information to understand the marine oxygen levels of the past.

The researchers plan to study other ancient extinctions to see if similar dramatic swings in oxygen coincided with any of those mass extinctions, which could have modern-day implications as climate change and increased nutrient discharge decrease the amount of oxygen in our present-day ocean.

"It's not just the loss of oxygen in the modern ocean," said Jeremy Owens, an associate professor in the Department of Earth, Ocean and Atmospheric Science and paper-co-author. "The loss of oxygen is important because the organisms living now are adapted for high oxygen, but if you have low oxygen there's also many organisms that may be able to adapt. Any rapid fluctuation in either direction will have an impact."

Read more at Science Daily

Stinkweed could make a cleaner bio-jet fuel, study finds

A common farm weed could make a "greener" jet fuel with fewer production-related environmental impacts than other biofuels, a new study indicates.

Growing the weed, pennycress -- often called stinkweed -- as a crop requires less fertilizer and fewer pesticides than other plants that can be used to make renewable jet fuel, according to the study. Pennycress also requires fewer farm operations, such as soil tilling, than other potential biofuel crops, reducing the associated environmental costs. Those costs include carbon dioxide emissions that cause the climate to change, as well as other emissions that pollute the air.

Environmental impacts could be further mitigated through farm management techniques that keep fertilizer on fields, rather than allowing it to run off into nearby watersheds, the study suggests. Such techniques can add to the financial cost of growing crops, but reduce their environmental footprints.

"Reducing greenhouse gas emissions from air travel will mean not just incremental changes, but a fundamental change in how we have been producing fuel and where that fuel comes from," said Ajay Shah, senior author of the study and associate professor of food, agricultural and biological engineering at The Ohio State University in Wooster. "And what we found is that pennycress might make a very good alternative fuel, especially when you consider the environmental costs of producing it."

The study was published recently online in the journal Applied Energy.

For this study, the researchers estimated the environmental impacts of growing pennycress, transporting it to a biorefinery and converting it to a usable jet fuel. They also accounted for the environmental costs of burning leftover byproducts of refining the pennycress seed into fuel.

Those environmental costs include fertilizer and pesticide use, water consumption and the energy required to harvest and transport pennycress seeds from a farm to a biorefinery and process them into usable fuel.

The researchers built computer models to determine how much total energy it would take to produce jet fuel from pennycress seeds and compared those estimates with the energy needed for producing biofuels from other crops. The data for the models came from existing studies about biofuel production.

Their models showed that it took about half as much energy to produce jet fuel from pennycress as it did to produce jet fuel from canola or sunflowers, two other potential bio-jet fuel crops. Pennycress oil production used about a third as much energy as soybean oil production, the researchers found, and the energy needed for turning pennycress into jet fuel was about the same as that used to produce fuel from the flowering plant camelina, another biofuel crop.

Renewable jetfuels are not yet financially competitive with fossil fuel-based fuels, Shah said. But calculating the environmental impacts of alternative bio-based fuels should help both farmers and policymakers as they try to limit carbon dioxide in the Earth's atmosphere and, hopefully, to slow or stop climate change.

"Pennycress also makes an appealing alternative jet fuel because of its growing season," Shah said. "It is a winter cover crop that can be grown between corn season and soybean season, giving the same body of farmland an extra production cycle each year.

"Pennycress can be planted when corn is still standing in the field, before the corn harvest," he said. "And it can be harvested before the soybean crops are planted. The bottom line is it can be used as a cover crop, it doesn't divert any agricultural production land, and it has suitable properties for renewable jet fuel production."

Greenhouse gas emissions from air travel contribute to climate change, accounting for about 2% of all human-induced carbon-dioxide emissions, according to various groups that study the effects of transportation on climate change.

"Reducing those emissions will almost certainly mean finding cleaner alternatives to jet fuels made from fossil fuels," Shah said. "Studies like this one can help determine the best alternative.

Read more at Science Daily

Pulsed lasers in liquids speed up hunt for effective catalysts

Chemical catalysts are the change agents behind the production of just about everything we use in our daily lives, from plastics to prescription drugs. When the right catalysts are mixed with the right chemical compounds, molecules that would otherwise take years to interact do so in mere seconds.

However, developing even one catalyst material to trigger this precise choreography of atoms can take months, even years, when using traditional wet chemistry procedures that use only chemical reactions, often in the liquid phase, to grow nanoparticles.

University of Rochester researchers say there is a way to shorten that process dramatically -- by instead using pulsed lasers in liquids to quickly create carefully tuned, systematic arrays of nanoparticles that can be easily compared and tested for use as catalysts.

The process is described in a Chemical Reviews article by Astrid Müller, an assistant professor of chemical engineering at the University of Rochester who has adapted the technique for her work on sustainable energy solutions. Three PhD students in her lab -- coauthors Ryland Forsythe, Connor Cox, and Madeleine Wilsey -- conducted an exhaustive review of almost 600 previous papers involving the use of pulsed lasers in liquids. As a result, their article is the most comprehensive, up-to-date survey of a technology that was first developed in 1987.

Pulsed lasers in liquids an 'indispensable tool' for discovering catalysts

So how does pulsed-laser-in-liquid synthesis work?
 

• A pulsed laser is directed at a solid material immersed in liquid. This creates a high-temperature, high-pressure plasma near the surface of the solid.
• As the plasma decays, it vaporizes molecules in the surrounding liquid, leading to a cavitation bubble. Within the bubble, chemical reactions begin to occur between particles from the liquid and particles that were ablated, or knocked loose, from the solid.
• After periodic expansions and contractions, the cavitation bubble violently implodes, causing shock waves and rapid cooling. Nanoparticles from the bubble condense in small clusters that are injected into the surrounding liquid and become stable.

The pulsed-laser-in-liquids technique offers multiple advantages over traditional wet-lab synthesis of nanomaterials. According to Müller:
 

• Because the reactions are confined primarily within the cavitation bubble, the resulting nanoparticles have remarkably uniform properties. "Every particle that is made is created under the same conditions," she says.
• The properties of the nanoparticles can be easily fine-tuned by adjusting the laser pulses and the chemical compositions of the solid and surrounding fluid.
• Laser-made nanocatalysts are intrinsically more active than those obtained by wet chemistry methods. Metastable nanomaterials with non-equilibrium structures and compositions can easily be produced. Such materials cannot be made under moderate temperatures and pressures.
• Laser synthesis can be controlled remotely, increasing the potential for large-scale industrial applications.
• Pulsed-laser-in-liquids synthesis of nanomaterials is also far more rapid than traditional methods. The technique can prepare bulk quantities of a nanoparticle in an hour or less. Systematic arrays of 70 materials can be made in a week.

"These advantages make this an indispensable as a tool for discovery," says Müller, whose background includes work in lasers, materials, and electrocatalysis. "You often have people who know lasers and materials, or maybe electrocatalysis and materials, but you very rarely get someone with expertise in all three."

She says, "This is what compelled us to write this paper, because the Müller group can bring together the perspectives of all three fields."

How catalysts can combat climate change

While working as a staff scientist at Caltech, Müller pioneered an adaption of the laser-in-liquids technique to prepare nonprecious water-splitting electrocatalysts that liberate oxygen from water to produce clean hydrogen. At Rochester, the Müller group expands on her expertise to study laser-made electrocatalysts as a way to turn climate-damaging carbon dioxide (CO2) into a closed cycle of useful liquid fuels, such as methanol or ethanol.

"If you were to burn these fuels again, you make CO2 again, so you go round and round. The carbon always stays within the cycle, and does not contribute to more climate change," Müller says. "For that to work we need catalysts, and no one knows yet what those catalysts would be -- what would work and why, and why other catalysts don't work."

Hence her interest in using pulsed-laser-in-liquid synthesis to accelerate the process. "It is hugely important because we can't just sit and hope for the best with climate change; we need to work on successor technologies now," she says.

So far, pulsed-laser-in-liquid synthesis has had only limited commercial use. The start-up cost of investing in laser technology is a stumbling block for many companies, Müller says. "But that will change as this method gets more and more traction," she believes.

Read more at Science Daily