Kathrin Weiland
Kathrin Weiland

Cow Manure and Elephant Dung Could Be Used to Make the Paper of the Future

Kathrin Weiland
Kathrin Weiland

The average dairy cow produces 82 pounds of manure daily. For elephants, that number is up to 300 pounds. According to researchers at the University of Vienna, all that dung represents an untapped resource that has the potential to change the way we make paper.

The team of scientists presented their findings at a meeting of the American Chemical Society on March 21. Waste from cows and elephants, they say, is rich in the same cellulose that's required to make paper products. What's more, the cellulose in manure has been broken down by digestion, making it easier for paper manufacturers to process.

"Animals eat low-grade biomass containing cellulose, chew it and expose it to enzymes and acid in their stomach, and then produce manure," researcher Alexander Bismarck said in a statement. "Depending on the animal, up to 40 percent of that manure is cellulose, which is then easily accessible."

Bismarck first got the idea to make paper from manure after seeing goats graze on dry grass in a small village in Crete. As he watched the plant matter go in, he wondered if that same matter wouldn't be suitable for making paper once it came out the other end. Today most paper is made by grinding down raw wood into nanocellulose, a process that takes a lot of power. The cellulose in dung has already been chewed and worn down by acid and enzymes in the animal's digestive system, cutting out the need for all that grinding.

Following Bismarck's goat manure–inspired revelation, he and his team began working with waste from horses, cows, and now elephants. Thanks to cattle farms and elephant parks around the world, this material is an abundant sustainable resource. The dung they collect is treated with a sodium hydroxide solution to remove lignin, the glue that holds cellulose fibers together (and can also be used as fuel). From there, they filter out other impurities like proteins and dead cells and bleach whatever's left with sodium hypochlorite to create a pure, white pulp that's ready to be made into paper.

The research team is currently exploring potential applications for the material. For now, they say it could be used as reinforcement for polymer composites or as filters for wastewater. It can also be made into paper for writing, though it may be a while until you see notebooks made from elephant dung at your local office supply store.

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'Lime Disease' Could Give You a Nasty Rash This Summer
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A cold Corona or virgin margarita is best enjoyed by the pool, but watch where you’re squeezing those limes. As Slate illustrates in a new video, there’s a lesser-known “lime disease,” and it can give you a nasty skin rash if you’re not careful.

When lime juice comes into contact with your skin and is then exposed to UV rays, it can cause a chemical reaction that results in phytophotodermatitis. It looks a little like a poison ivy reaction or sun poisoning, and some of the symptoms include redness, blistering, and inflammation. It’s the same reaction caused by a corrosive sap on the giant hogweed, an invasive weed that’s spreading throughout the U.S.

"Lime disease" may sound random, but it’s a lot more common than you might think. Dermatologist Barry D. Goldman tells Slate he sees cases of the skin condition almost daily in the summer. Some people have even reported receiving second-degree burns as a result of the citric acid from lime juice. According to the Mayo Clinic, the chemical that causes phytophotodermatitis can also be found in wild parsnip, wild dill, wild parsley, buttercups, and other citrus fruits.

To play it safe, keep your limes confined to the great indoors or wash your hands with soap after handling the fruit. You can learn more about phytophotodermatitis by checking out Slate’s video below.

[h/t Slate]

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Why Eating From a Smaller Plate Might Not Be an Effective Dieting Trick 
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It might be time to rewrite the diet books. Israeli psychologists have cast doubt on the widespread belief that eating from smaller plates helps you control food portions and feel fuller, Scientific American reports.

Past studies have shown that this mind trick, called the Delboeuf illusion, influences the amount of food that people eat. In one 2012 study, participants who were given larger bowls ended up eating more soup overall than those given smaller bowls.

However, researchers from Ben-Gurion University in Negev, Israel, concluded in a study published in the journal Appetite that the effectiveness of the illusion depends on how empty your stomach is. The team of scientists studied two groups of participants: one that ate three hours before the experiment, and another that ate one hour prior. When participants were shown images of pizzas on serving trays of varying sizes, the group that hadn’t eaten in several hours was more accurate in assessing the size of pizzas. In other words, the hungrier they were, the less likely they were to be fooled by the different trays.

However, both groups were equally tricked by the illusion when they were asked to estimate the size of non-food objects, such as black circles inside of white circles and hubcaps within tires. Researchers say this demonstrates that motivational factors, like appetite, affects how we perceive food. The findings also dovetail with the results of an earlier study, which concluded that overweight people are less likely to fall for the illusion than people of a normal weight.

So go ahead and get a large plate every now and then. At the very least, it may save you a second trip to the buffet table.

[h/t Scientific American]

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