3-D Recycling: Grind, melt print!

A new desktop recycler turns trash into 3-D printer ‘ink'.

Three-dimensional, or 3-D, printers make it possible to “print” almost any object with a computer. The machines produce items by laying down tiny drops, or pixels, of material one layer at a time. That material can be made from plastic, metal or even human cells. But just as the ink for standard computer printers can be expensive, 3-D printer “ink” can be quite pricey too. Meanwhile, society faces a growing mound of plastic trash. Now three Canadian engineering students have found a way to deal with both problems: Recycle plastic waste into spools of 3-D printer ink. 

The first part of their new machine is a plastic recycler. It grinds and crushes waste plastic into uniform bits about the size of peas or large grains of rice. The waste can be used drink bottles, coffee cup lids or other plastics. But this trash must be clean.

Users must grind only one type of plastic in any given batch. Otherwise, the ink-making part of the process may not work well, notes Dennon Oosterman. He worked on the new machine with fellow students Alex Kay and David Joyce. All three attend the University of British Columbia in Vancouver, Canada.

The machine stores the plastic bits in a drawer until there are enough for a spool of “ink.” Then those bits go into the next part of the machine. It’s called an extruder.

To extrude something means to push it out. To do that, this part of the system first melts the plastic bits. A little of that melted plastic attaches to a spool. The spool then turns, pulling a long, thin thread of the plastic out of the machine. “You can think about stretching gum apart,” explains Oosterman. But instead of becoming a mess of stringy goo, the plastic cools and winds neatly onto the spool.

The machine pulls out and winds as much as three meters (10 feet) of plastic thread per minute. At that rate, it takes roughly two hours to make a one-kilogram (2.2 pound) spool of plastic thread. That’s about 40 percent faster than other small-scale plastic-ink makers, Oosterman says.

This ‘smart’ self-cleaning keyboard is powered by you

The bonus: It works for its owner and no one else.

 

A new keyboard can tell if you’re its owner. It locks out anyone else, even if that person knows your password. What’s more, this device needs no batteries. It harvests all the energy it needs from the action of your typing.

All in all, “This will hugely improve the security of a computer,” predicts Zhong Lin Wang. He’s a materials scientist at the Georgia Institute of Technology in Atlanta and a co-designer of the new keyboard.
“Our fingertips have electrostatic charges,” explains Wang. That means there’s an imbalance of electrons. Your fingertips generally have a slight positive charge. So they have somewhat fewer electrons than the area around them. And that principle makes it possible for typing to induce an electric current in the keyboard, Wang points out.

To understand how this works, consider a magnet. At one end is a positive charge. At the other is a negative charge. Opposite poles attract. So if you put the positive end of one magnet next to the negative one of another, they will latch onto each other. A similar idea applies to electrostatic charges. Positive charges attract negative ones.

Wang’s group put two layers of metal electrodes under the keyboard’s plastic surface. When a finger approaches a key, it attracts free electrons to the top electrode. The bottom electrode supplies them. As soon as the finger lifts off of the key, the electrons flow back to the lower electrode. Any flow of electrons creates an electric current.

And this induced electric current can power the keyboard — but only if the current is strong enough. To achieve that, the Georgia Tech team focused on nanotechnology. (“Nano-“ refers to things measured on the scale of 100 billionths of a meter or less.)

Inside Steve Jobs schools: swapping books for iPads

Schools in the Netherlands have shunned textbooks and only use Apple tablets for teaching and learning. A year in, journalist Sarah Marsh investigates how pupils and teachers are faring.

 

The glimmer of screens hypnotises a group of children who swipe their hands from side to side and then up and down, captivated by what’s in front of them. This isn’t a scene from a sci-fi film or a description of the electronics floor in Hamley’s toy shop, it is life inside Netherlands’ new iPad schools.

Just over a year ago, seven schools serving 1,000 four- to 12-year-olds opened their doors in cities such as Amsterdam and Almere. Because of their focus on learning through iPads, these institutions – pioneered by market researcher and entrepreneur Maurice de Hond – became known as “Steve Jobs schools”. There are now 22 of them across the Netherlands.

There are no notebooks, blackboards or even formal lesson plans: children drop into 30-minute workshops on various subjects. There are no seating plans and 45% of learning takes place on an iPad which every child is given when they join.

What workshop each pupil goes to is decided by teachers, parents and the pupils themselves as part of their six-week learning plan. De Hond says it is about children achieving specific learning goals with teachers acting as “talent coaches”. Children must attend school for a full day, but the devices let them learn at any time anywhere, taking screen grabs to indicate their progress to teachers.

Marina Donker, who teaches at The Ontplooiing Steve Jobs School in Amsterdam, explains that they use web-based learning programmes which adapt work to a child’s results. “There are no piles of school notebooks at the and of the day waiting for us. Children can work by themselves in a quiet room; this means that we can work with smaller groups during our workshops.”

 
While these schools offer a unique approach, the use of iPads in classrooms is not new. According to Apple, more than 10m iPads have been purchased by educational institutions worldwide, 7m in the US and 750,000 in the state of Texas alone.

De Hond has noticed children getting more self-assured in their learning over the year in his schools. There has been no formal research conducted so far, but De Hond believes iPads are helping children to concentrate for longer, having a particularly positive impact on those who suffer from attention deficit disorder (ADD).

Screen time: Most U.S. teens overindulge

Most American 12- to 15-year olds spend too much time at their computers and watching TV.

It’s unhealthy to be a couch potato. Yet, a new study finds, at least 70 percent of U.S. 12- to 15-year olds spend too much time in front of a TV or computer.

Kirsten Herrick works for the Centers for Disease Control and Prevention, or CDC, in Hyattsville, Md. She and other CDC scientists analyzed data collected in 2012 as part of two major surveys. One was the National Health and Nutrition Examination Survey. The other was the National Youth Fitness Survey. Each survey asked a representative cross-section of all Americans to answer a series of questions.

Almost every kid in the United States regularly watches TV, the data show. More than 90 percent spend at least some time each day on a computer. Enjoying each is fine, the researchers say. The trick is not to overindulge. And that would be watching TV and/or playing on a computer for more than 2 hours a day. 

Two groups established that recommended screen-time limit. One is the American Academy of Pediatrics (doctors who specialize in the health of children and teens). The second is the National Heart, Lung and Blood Institute. Its researchers focus on heart health. Both groups are concerned about kids who substitute athletic sports and other vigorous exercise for couch potato pursuits. Too much time in front of a TV or computer screen has been linked in adolescence with being overweight (or obese), having high blood pressure and having elevated cholesterol. Each of these features put individuals at risk of heart disease.