polymic

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FN FS2000

Civilian model of the F2000, this polymer bullpup rifle has been discontinued according to FN. Uses only metal (steel or aluminum) AR-15 magazines. Polymer mags won’t work because of the anti-dust gasket seal in the mag well. Note in the 3rd photo the top rail. This model is the later version called the Tactical. It lacks the cut outs on the top of the receiver, making it unable to use the factory integrated optic shell housing seen in earlier models. (GRH)

Nanotech could give us safer, greener diapers and sanitary products

A new material made of tiny nanofibers could replace potentially harmful materials found in diapers and sanitary products, according to new research published in Applied Materials Today.

The authors of the new paper, from the Indian Institute of Technology, say their new material would have less of an environmental impact and be safer for humans than existing materials.

For the last few decades, disposable diapers, sanitary napkins and other sanitary products have been made absorbent using superabsorbent polymers (SAPs). These materials are capable of absorbing many times their own weight in liquid; the average diaper can absorb 30 times its own weight in bodily fluids. But the material is not biodegradable: in ideal conditions, it can take as long as 500 years for a diaper to degrade. And SAPs have been linked to health problems like Toxic Shock Syndrome, leading to their ban in tampons in the 1980s.

Read more.

Here’s a special Daily Bird post while I’m in the middle of a big work project–

Today is my wedding anniversary, and I had a cake topper made by the talented Holly Mongi. This is the Distelfink, or thistlefinch, and it’s found all over Pennsylvania Dutch culture. It’s the bird of good luck and happiness. Holly felted the bodies, used real feathers for the tails and head feathers, and made the base out of one of those really good kinds of polymer clay. 

Today we keep the little birdies in a special case (you can see the sides of it in the photos, I removed half of it) and continue to admire them. 

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Beretta ARX100

Civilian model of the ARX160, this Italian made rifle is composed largely of polymer. Most of the weight is concentrated towards the muzzle, making it somewhat front heavy but not as bad as some other rifles. Completely ambidextrous, it operates with a gas piston system. One particular flaw it has is its inability to use Gen 3 Magpul mags. (GRH)

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If you’ve ever bitten into a chocolate-covered bonbon, you may have noticed that the candy’s chocolate coating is remarkably uniform. Inspired by this observation, a group of engineers have investigated how viscous fluids poured over a curved surface flow and solidify; their findings were published this week. 

Rather than heated chocolate, the group used polymer-filled fluids that cure and harden over time. Interestingly, they found that the final shell is quite uniform and that its thickness does not depend on the pouring technique. Instead, they can predict the final shell thickness based on the radius of the mold and the rheological properties of the fluid–specifically its density, viscosity, and curing time. The reason for this is that the time it takes for the fluid to drain and coat the mold is much shorter than the time it takes for the polymer to cure. As a result, the amount of fluid that sticks to the mold depends on geometry and fluid properties - not how the fluid was poured. 

Amateur confectioners rejoice: pouring uniform chocolate coatings may be easier than you thought!  (Image credit: MIT News, video; research credit: A. Lee et al.)