chemistry

Stretchy And Washable Batteries | Earth Wise

January 13, 2022 By EarthWise Leave a Comment

Wearable electronic devices are a big market but there are limitations created by the properties of the batteries that operate them. The ideal battery for wearable electronics would be soft and comfortable, stretchable, and washable. Researchers at the University of British Columbia have recently developed just such a battery. The work has been described in a new paper published in Advanced Energy Materials.

The battery encompasses a number of engineering advances. Traditional batteries are made from hard materials encased in a rigid external shell. The UBC battery is stretchable because its key components are ground into small pieces and then embedded in a rubbery polymer. Ultra-thin layers of these materials are then encased in the same polymer. This construction creates an airtight, waterproof seal.

The batteries survived 39 cycles in washing machines using both home and commercial-grade appliances. The batteries came out intact and functional.

The batteries use zinc and manganese dioxide chemistry which is safer than lithium-ion batteries in case they break while being worn.

The materials used are low-cost, so if the technology is commercialized, it will be cheap. When it is ready for consumers, it is likely to cost no more than existing batteries. Work is underway to increase the power output of the batteries and their cycle life. There is already commercial interest in the technology.

There are many potential applications for such batteries. Apart from watches and medical monitors, they might also be integrated with clothing that can actively change color or temperature. If the batteries are commercialized, they will make wearable power comfortable, convenient, and resilient.

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Stretchy, washable battery brings wearable devices closer to reality

Photo, posted April 15, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Why Do Trees Change Color? | Earth Wise

December 24, 2020 By EarthWise Leave a Comment

We had a particularly colorful fall in the Northeast this year. Almost everywhere you looked, there were brilliant displays of yellow, orange, and red. The colors of fall are a result of chemistry and environmental events that may have taken place many months in the past.

The color of leaves comes from 4 pigments whose effects are governed by photosynthesis. The one that is actually used in photosynthesis is chlorophyll and it causes leaves to be green. But when a tree begins to prepare for dormancy, it stops producing chlorophyll, the green pigmentation fades, and the other pigments that were already in the leaves become visible.

There are xanthoplylls, which are the yellow pigments that are seen the most in fall trees. They are the same pigments that color egg yolks and sometimes parts of the human eye. They are only produced by plants and appear in humans and animals only through consumption.

There are carotenes, which are the orange pigments found in fruits and vegetables, such as carrots, oranges, some bell peppers and squashes.

And there is anthocyanin, which is the pigment found in blueberries, blackberries, and red or violet roses. Its color depends on the pH level of the plant; higher pH leads to darker color. This is the pigment seen in red maples, black cherry trees, Shumard oaks, and more. Only 10% of trees in temperate climates produce anthocyanin and its red pigmentation and most of those trees are in New England.

All these pigments serve purposes. They help trees absorb light energy, prevent sun damage, and even regulate how much energy chlorophyll produces.

There are complicated chemical and environmental factors at play in fall foliage but when they come together like they did this year, it’s a magnificent spectacle.

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Why Do Trees Change Color?

Photo, posted October 17, 2020, courtesy of John Brighenti via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Forests As Carbon Sinks | Earth Wise

April 21, 2020 By EarthWise Leave a Comment

Tropical forests are an important part of the global carbon cycle because they take up and store large amounts of carbon dioxide. Because of this, deforestation in the Amazon and other tropical forests is a major contributor to the growing CO2 levels in the atmosphere.

Therefore, climate models need to accurately take into account the ability of tropical forests to sequester carbon. It turns out that this is not such a simple matter. A new study by the International Institute for Applied Systems Analysis sought to determine how much detail about tropical forests is needed in order to make valid assumptions about the strength of forest carbon sinks.

They looked at the role of both biotic factors – differences between plant species that are responsible for capturing more or less carbon from the atmosphere – and abiotic factors – local environmental factors like soil properties that also influence carbon sink strength.

It is generally assumed that more diverse forest communities capture available resources more efficiently as a result of complementary characteristics and preferences of certain species to specific conditions. Factors like soil texture and chemistry are also important. In general, the results show that abiotic and biotic factors interact with one another to determine how much carbon can be stored by the ecosystem.

Traditional projections of the role of tropical forests in storing carbon mostly rely on remote sensing techniques that integrate over large spatial areas. The new study shows that there can be large differences in the carbon storing ability of tropical forests and that more detailed models are needed to produce more accurate projections.

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Shedding light on how much carbon tropical forests can absorb

Photo, posted July 17, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Permafrost | Earth Wise

February 26, 2020 By EarthWise Leave a Comment

The Arctic is warming faster than any region on Earth and mostly we’ve been hearing about the rapid disappearance of Arctic sea ice. But the land in the Arctic is also undergoing major changes, especially to the permafrost that has been there for millennia.

Permafrost occurs in areas where the temperature of the ground remains below freezing for two years or more. About a quarter of the Northern Hemisphere’s landscape meets this criterion. Most of the world’s permafrost is found in northern Russia, Canada, Alaska, Iceland, and Scandinavia.

Permafrost regions previously carpeted in cranberries, blueberries, shrubs, sedges, and lichen are now being transformed into nothing but mud, silt, and peat. So-called regressive thaw slumps – essentially landslides – are creating large craters in the landscape. (The Batagaika Crater in the Yana River Basin of Siberia is a kilometer long and 100 meters deep).

Apart from the violence being done to the Arctic landscape, the greatest concern is that the permafrost has locked in huge stores of greenhouse gases, including methane, carbon dioxide, and nitrous oxide. It is estimated that the permafrost contains twice as much carbon as is currently contained in the atmosphere. As the permafrost thaws, these gases will be released. With them will be pathogens from bygone millennia whose impact cannot be predicted. Climatologists estimate that 40% of the permafrost could be gone by the end of the century.

As the permafrost thaws, the region’s ecosystems are changing, making it increasingly difficult for subsistence indigenous people and Arctic animals to find food. Landslides are causing stream flows to change, lakes to suddenly drain, seashores to collapse, and water chemistry to be altered.

The warming Arctic is about much more than disappearing sea ice.

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How Thawing Permafrost Is Beginning to Transform the Arctic

Photo, posted February 9, 2017, courtesy of the U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Removing Microplastics with Magnetism

October 7, 2019 By EarthWise 2 Comments

A new method for removing microplastics from the oceans has emerged from, of all things, a science fair project. An Irish 18-year-old named Fionn Ferreira developed his project for the annual Google Science Fair and it won the grand prize of $50,000 in educational funding.

The teenager was walking on the beach in his hometown and ran across a stone with oil and plastic stuck to it and became focused on the problem of microplastics increasingly entering the environment.

His idea was to make use of ferrofluids, which are nontoxic magnetic fluids made of oil and magnetite, which is an iron-based mineral. In the presence of water, the ferrofluids attract microplastics because both have similar properties.

Ferreira added oil and magnetite to water and mixed in a solution of microplastic particles. When the microplastics latched onto the ferrofluids, he dipped a magnet into the solution several times and the magnet removed both substances, leaving clear water. After almost 1000 tests, he demonstrated the method to be 88% effective in removing a variety of microplastics from water; a result even better than his original hypothesis of an 85% removal rate.

Ferreira is planning to further his education at a prestigious chemistry institute in the Netherlands starting in the fall.

According to a recent study, Americans eat, drink and breathe between 74,000 and 121,000 microplastic particles each year and, if they drink bottle water only instead of tap water, an additional 90,000 particles. So, a science fair project that might provide a way to get rid of most these things is definitely prize-worthy.

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This Irish teenager may have a solution for a plastic-free ocean

Photo, posted April 25, 2016, courtesy of Boe Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

New Membranes For Carbon Capture

October 2, 2019 By EarthWise Leave a Comment

Drastically reducing the amount of carbon dioxide being emitted into the atmosphere is an essential goal in the effort to mitigate the effects of climate change. While the ultimate solution is to avoid combustion of fossil fuels by the use of clean alternative energy sources, that transition will take time – possibly more time than we have. As a result, there is a great deal of effort underway to develop techniques for capturing the carbon emitted by fossil fuel combustion and either recycling it or storing it.

There are multiple ways to capture carbon emissions, but the ultimate goal is to find a technique that is both inexpensive and scalable. One promising technique involves the use of high-performance membranes, which are filters that can specifically pick out CO2 from a mix of gases, such as those coming out of a factory smokestack.

Scientists at a Swiss laboratory have now developed a new class of high-performance membranes that exceeds the targeted performance for carbon capture by a significant margin. The membranes are based on single-layer graphene with a selective layer thinner than 20 nanometers – only about 40 atoms thick. The membranes are highly tunable in terms of chemistry, meaning that they can be designed to capture specific molecules.

The membranes are highly permeable – meaning that they don’t impede gas flow too much – but highly selective. The CO2/N2 separation factor is 22.5, which means that 22.5 times more nitrogen can get through the membrane than carbon dioxide.

The work is just at the laboratory stage at this point, but it is a very promising step towards developing a practical scheme for keeping carbon dioxide from escaping from power-plant and factory smokestacks.

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Next-gen membranes for carbon capture

Photo, posted December 28, 2010, courtesy of Emilian Robert Vicol via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Giant Seaweed Bloom

August 19, 2019 By EarthWise Leave a Comment

Scientists using data from NASA satellites have discovered and documented the largest bloom of seaweed in the world, stretching all the way from West Africa to the Gulf of Mexico. The gigantic macroalgae bloom has been dubbed the Great Atlantic Sargassum Belt.

The brown seaweed floats in surface water and in recent years has become a problem to shorelines lining the tropical Atlantic, Caribbean Sea, Gulf of Mexico, and east coast of Florida. The stuff carpets popular beach destinations and crowded coastal waters. In 2018, more than 20 million tons of it floated on the ocean surface.

Scientists have been studying the Sargassum algae using satellites since 2006, but the major blooms have only started appearing since 2011. They have occurred every year between 2011 and 2018 except for 2013. Before 2011, most of the free-floating Sargassum in the ocean was primarily found in patches around the Gulf of Mexico and the Sargasso Sea located on the western edge of the central Atlantic Ocean.

Sargassum provides habitat for turtles, crabs, fish and birds, and produces oxygen via photosynthesis. However, too much of it can crowd out many marine species.

According to researchers, the ocean’s chemistry must have changed in order for the bloom to get so out of hand. The factors involved include a large seed population left over from a previous bloom, nutrient input from West Africa, and nutrient input from the Amazon River. The increase in nutrients may be a result of deforestation and fertilizer use.

Climate-change effects on precipitation and ocean currents ultimately do play a role in this, but increased ocean temperatures do not. Unfortunately, these giant seaweed blooms are probably here to stay.

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NASA Satellites Find Biggest Seaweed Bloom in the World

Photo courtesy of NASA.

Earth Wise is a production of WAMC Northeast Public Radio.

Another Way To Make Solar Cells

March 21, 2019 By EarthWise Leave a Comment

Millions of rooftops now contain solar panels and the majority of the solar cells that make up those panels today are made from silicon. Silicon solar cells require expensive, multi-step processing conducted at very high temperatures in special clean room facilities. Despite these complications, the price of solar panels has continued to drop dramatically over the years.

But even as the price of solar cells gets lower and lower, there are still widespread efforts to find even better ways to make them. One of those ways is with perovskite solar cells. Perovskites are materials with a characteristic crystal structure and are quite common in nature. Perovskites can be formed with a wide range of elements and can exhibit a variety of properties.

They were first used to make solar cells about 10 years ago and those first cells were unimpressive in most respects. However, there has been steady progress since that time. The potential advantages of perovskite solar cells are that they can be made from low-cost materials and can be manufactured using liquid chemistry, a far cheaper process than what is used to make silicon cells.

Researchers at MIT and several other institutions have recently published the results of research on how to tailor the composition of perovskite solar cells to optimize their properties. What used to be a trial-and-error process can now become much more engineered and should lead to perovskite solar cells with performance that could exceed that of silicon cells.

Silicon solar panels are a huge, worldwide industry and displacing them in favor of an alternative technology is a tall order. But if perovskite cells can be optimized for large-scale manufacturability, efficiency and durability, they could definitely give silicon a run for its money.

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