TWIE 160: Self-Healing Metals

This Week in Engineering - Teen-invented cancer test; tabletop chemical weapons disposal; prosthetic touch; world's strongest material; self-healing metals; and wristband thermostat.

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Teen-invented cancer test
When Jack Andraka lost a close family friend to pancreatic cancer, the then-13-year-old started studying the disease.  He found 85% of cases are diagnosed late, when survival rates are around two percent, primarily because the test for the disease is expensive, around $800, and inaccurate, with 30% false negatives.  He crunched data on 8000 proteins and found one, mesothelin, that correlated with pancreatic cancer, then developed an inexpensive test for the protein by dipping paper in a solution containing carbon nanotubes and antibodies that react to the protein.   The resulting sensor costs three cents and takes five minutes to yield an answer.  Andraka won the Intel International Science and Engineering Fair for his efforts.

Tabletop chemical weapons disposal
In an effort to make the disposal of chemical weapons safer and easier, the Pentagon recently put out a call for a tabletop device capable of neutralizing chemical and biological weapons without separating them from their containers.  X-rays will break down chemical agents like sarin gas, but a portable system has been difficult to build.  Now, former Brookhaven National Lab researcher Young Bae has proposed a technique for generating x-rays using “warm dense matter”, which the Pentagon is hoping to refine.  Better than my idea for disposing of WMDs -- a perilous quest to the fires ‘neath Mount Doom.

Prosthetic touch
Research has created some prosthetics that can be controlled by thoughts, but since the prosthetic has no sense of touch, the wearer can easily break dishes or bruise fruit.  Now, researchers from the University of Chicago and Johns Hopkins have shown they can send electrical signals directly in the brains of rhesus macaques that are interpreted as touch with varying pressure.  After the macaques were taught to look left or right after touches on their hands, they did the same with the electrical signals.  The research might, after several years, lead to prosthetics hard-wired to the brain with an intuitive sense of touch.  And I am that much closer to my lifelong dream of playing Red Hands with Def Leppard’s drummer.  They said it could never be done!

World’s strongest material
Computer models from Rice University have proven that Carbyne is the world’s strongest material.  Made of a chain of carbon atoms held together by either double or alternating single and triple atomic bonds, carbyne has proven itself to be 200 times stronger than steel, and with double the tensile strength of graphene.  Currently, there is no method to manufacture the material in bulk, but if one is discovered, possible applications would include nanomechanical systems and spintronic devices.

Self-healing metals
Researchers at MIT found behavior first thought to be a mistake -- a cracked piece of metal that, when tension is applied, actually pulls itself back together.  The reason for the mysterious trait was related to how grain boundaries interact with cracks in the metal’s crystalline microstructure, and computer models demonstrated the mechanism.  The researchers now plan to study how to design new alloys with the behavior.  You know what I wish could heal its own tears?  That check from a media mogul who wanted to turn this show into a refrigerator infomercial.  Stupid integrity.

Wristband thermostat
Engineering students from MIT have developed Wristify, a prototype thermoelectric bracelet that can keep the wearer at just the right temperature for personal comfort.  The device takes air and skin temperature measurements to determine how hot or cold the person feels, and then sends thermal pulses into the wrist to warm or cool the