Internal Power Pills

Arguably the biggest hurdle to implanted electronics is in the battery. A modern mobile phone can run for a day or two without a charge, but that only needs to fit into a pocket and were its battery to enter a dangerous state it can be quickly removed from the pocket. Implantable electronics are not so easy to toss on the floor. If the danger of explosion or poison isn’t enough, batteries for implantables and ingestibles are just too big.

Researchers at MIT are working on a new technology which could move the power source outside of the body and use a wireless power transfer system to energize things inside the body. RFID implants are already tried and tested, but they also seem to be the precursor to this technology. The new implants receive multiple signals from an array of antennas, but it is not until a couple of the antennas peak simultaneously that the device can harvest enough power to activate. With a handful of antennas all supplying power, this happens regularly enough to power a device 0.1m below the skin while the antenna array is 1m from the patient. Multiple implants can use those radio waves at the same time.

The limitations of these devices will become apparent, but they could be used for releasing drugs at prescribed times, sensing body chemistry, or giving signals to the body. At this point, just being able to get the devices to turn on so far under flesh is pretty amazing.

Recently, we asked what you thought of the future of implanted technology and the comment section of that article is a treasure trove of opinions. Maybe this changes your mind or solidifies your opinion.

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Find and Repair a 230kV 800Amp Oil-Filled Power Cable Feels Like Mission Impossible

How do you fix a shorted cable ? Not just any cable. An underground, 3-phase, 230kV, 800 amp per phase, 10 mile long one, carrying power from a power station to a distribution centre. It costs $13,000 per hour in downtime, counting 1989 money, and takes 8 months to fix. That’s almost $75 million. The Los Angeles Department of Water and Power did this fix about 26 years ago on the cable going from the Scattergood Steam Plant in El Segundo to a distribution center near Bundy and S.M. Blvd. [Jamie Zawinski] posted details on his blog in 2002. [Jamie] a.k.a [jwz] may be familiar to many as one of the founders of Netscape and Mozilla.

To begin with, you need Liquid Nitrogen. Lots of it. As in truckloads. The cable is 16 inch diameter co-axial, filled with 100,000 gallons of oil dielectric pressurised to 200 psi. You can’t drain out all the oil for lots of very good reasons – time and cost being on top of the list. That’s where the LN2 comes in. They dig holes on both sides (20-30 feet each way) of the fault, wrap the pipe with giant blankets filled with all kind of tubes and wires, feed LN2 through the tubes, and *freeze* the oil. With the frozen oil acting as a plug, the faulty section is cut open, drained, the bad stuff removed, replaced, welded back together, topped off, and the plugs are thawed. To make sure the frozen plugs don’t blow out, the oil pressure is reduced to 80 psi during the repair process. They can’t lower it any further, again due to several compelling reasons. The cable was laid in 1972 and was designed to have a MTBF of 60 years.

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