electrical engineering

Radioactive Power: The Nuclear Battery

If you’re fed up with your phone battery not lasting through the day, there may be a solution in the future: nuclear batteries. These don’t derive their energy from chemical reactions like ordinary batteries; instead, nuclear batteries harness the energy created in radioactive decay.

Before you get freaked out about having a nuclear meltdown in your phone, nuclear batteries don’t actually contain tiny fission reactors. They don’t utilise chain reactions, and they’re actually much more akin to solar cells, but instead of generating electricity from photons, they generate electricity from high-energy electrons that are emitted when radioactive elements decay.

Betavoltaic batteries are one type of nuclear battery, harnessing energy from beta decay. They’re constructed almost exactly like a solar cell, with a piece of semiconductor like silicon sandwiched between two electrodes, so when radiation hits the silicon, a flow of electrons is produced. Since beta radiation can be stopped with just a thin film of aluminium (whereas gamma radiation needs a slab of lead or concrete), betavoltaic batteries are pretty safe.

They’re also not at all new: the first beta cell was demonstrated in 1913, and betavoltaic batteries have been used in the military, satellites, spacecraft and older models of pacemakers for years, because they have an extremely long life. The Curiosity Rover is powered by a nuclear battery containing plutonium-238, which will last it 14 years. Typically, though, they’re quite large because the semiconductor material is damaged by the high-energy particles, so batteries must be built large to last as long as the radioactive isotope. Their size has limited their use, but recently, researchers at the University of Missouri have been developing a nuclear battery the size of a penny that holds a million times more charge than regular batteries.

Led by Associate Professor Jae Wan Kwon, the researchers are using a liquid semiconductor—a water-based solution—instead of a solid one, which minimises the problem of semiconductor damage. Water absorbs the beta radiation from strontium-90 like a buffer, and the radiation also splits up the water molecules to produce free radicals and energy that increase the battery’s efficiency. A titanium dioxide electrode then collects the energy and converts it into electrons.

The team are working on improving the prototype by making it smaller and more efficient. For now, the price and the risk mean nuclear batteries are mainly confined to use in military and space applications, but we can all dream of a phone with a battery life of decades.

Fully transparent solar cell could make every window in your house a power source
The first fully transparent solar cell harnesses wavelengths of light that are invisible to the human eye in order to generate power.

So, to achieve a truly transparent solar cell, the Michigan State team created this thing called a transparent luminescent solar concentrator (TLSC), which employs organic salts to absorb wavelengths of light that are already invisible to the human eye. Steering clear of the fundamental challenges of creating a transparent photovoltaic cell allowed the researchers to harness the power of infrared and ultraviolet light.

The TLSC projects a luminescent glow that contains a converted wavelength of infrared light which is also invisible to the human eye. More traditional (non-transparent) photovoltaic solar cells frame the panel of the main material, and it is these solar cells that transform the concentrated infrared light into electricity.

Scientists store digital images in DNA, and retrieves them perfectly

Technology companies routinely build sprawling data centers to store all the baby pictures, financial transactions, funny cat videos and email messages its users hoard.

But a new technique developed by University of Washington and Microsoft researchers could shrink the space needed to store digital data that today would fill a Walmart supercenter down to the size of a sugar cube.

The team of computer scientists and electrical engineers has detailed one of the first complete systems to encode, store and retrieve digital data using DNA molecules, which can store information millions of times more compactly than current archival technologies.

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Half a Million Volts Surround This High Voltage Power Line Inspector

In electrical engineering, live-line working is the maintenance of electrical equipment, often operating at high voltage, while the equipment is energized.

A lineman wearing a Faraday suit can work on live, high-power lines by being transported to the lines in a helicopter. Wearing the suit, they can crawl down the wires.

More Than You Ever Wanted to Know About Math: Euler’s Formula

We’ve looked at how you can translate a sinusoidal voltage or current between trigonometric, polar, and rectangular coordinate forms.

Being able to do this makes it way easier to deal with these mathematically: rather than remembering a whole bunch of trig formulas and identities, we can just stick with regular addition, subtraction, multiplication, and division.

Euler’s formula is the reason we can do this. Euler’s formula is both simple and powerful and it comes up over and over again in electrical engineering. It relates the sine and cosine functions to both the imaginary number j (or i, if you’re not dealing with electrical engineering) and the constant e. It looks like this:

Looks like the way we did rectangular coordinates, right? That’s exactly what it is.

We don’t normally write polar notation with the exponential, but that’s just what it is. When we write the polar expression A /_ φ, it’s just a shorthand for Ae^(jφ). Knowing this, you can see why the translation between polar and rectangular coordinates makes sense:

Euler’s formula will come up again for us numerous times. There’s other stuff you can do with it, but for now just keep in the back of your mind that sines, cosines, and exponentials are related and that you can switch back and forth between them at will.


april 2nd, 2016 // there’s a new Starbucks on campus and it’s my new favourite place! I spent some time with my bullet journal today listing all the topics I need to study for my final exams and making a study plan. four weeks until I’m done!! I also went bouldering and had a meeting for a group project so I’d say today has been pretty productive ✌🏻