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Category: energy – Page 366

A new approach developed by researchers at the University of Waterloo could hold the key to greatly improving the performance of commercial lithium-ion batteries. The scientists have developed a new type of silicon anode that would be used in place of a conventional graphite anode, which they claim will lead to smaller, lighter and longer-lasting batteries for everything from personal devices to electric vehicles.

Graphite has served the lithium-ion battery world as material for negative electrodes well so far, but also presents something of a roadblock for improved capacity. This is due to the relatively small amount of energy it can store, which comes in at around 370 mAh/g (milliamp hours per gram). Silicon has become an increasingly popular substitute for battery researchers looking to up the ante, with a specific capacity of 4,200 mAh/g. However, it isn’t without its limitations either.

As silicon interacts with lithium inside the cell during each charge cycle, it expands and contracts by as much as as 300 percent. This immense swelling brings about cracks that diminish the battery’s performance over time, leading to short circuits and ultimately cell failure. Other recent attempts to overcome this problem have turned up battery designs that use sponge-like silicon anodes developed at the nanoscale, silicon nanowires measuring only a few microns long and ones that bring graphene and carbon nanotubes into the mix.

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A Hall thruster is powering many of the satellites moving around Earth right now. It needs 100 million (yes, you read that right, 100 million) times less fuel than chemical thrusters. But it was never remotely sturdy enough to get anything to Mars—until now.

Typical chemical thrusters are pretty simple. Fuel combusts, gases shoot one way, and a rocket shoots the other way.

Ion thrusters are a little different. They contain charged electrodes, an anode and a cathode, and allow positively charged ions to shoot from the anode to the cathode. Thanks to momentum, the ions will “overshoot” the cathode. Under regular circumstances they’d be sucked back, but once they’ve cleared the cathode, they’re hit by a beam of electrons, neutralizing them and allowing them to go on their way without interference from the charged cathode. So the neutralized atoms shoot one way, and the rocket shoots another.

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Samsung’s latest battery prototypes could lead not only to more powerful wearables, but also to unusual ones. The first model called Band is meant to be attached to smartwatch straps, as its name implies, to add as much as 50 percent of the device’s original battery life. Stripe, on the other hand, is the thin, bendy strip the model above is holding in her hands — and the more versatile between the two. Since it’s extremely thin (it has a depth measuring 0.3mm), it could be used to create all kinds of wearables, such as smart necklaces and headbands, or even interactive clothing designs. According to Samsung, it has higher energy density than current comparable batteries, though it didn’t name any particular brand and model.

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The prospect of interstellar travel is no longer sci-fi. It COULD be achievable within our lifetime! But, how would an interstellar rocket-ship work? On this week’s episode of Space Time, Matt talks options for interstellar travel — from traditional rocket fuel to antimatter drives, could we travel to other star systems? Watch this episode of Space Time to find out!

“Quantum Entanglement & Spooky Action at a Distance”:

Continue reading “5 REAL Possibilities for Interstellar Travel | Space Time | PBS Digital Studios” | >

(Phys.org)—Scientists have built a battery containing a magnetic fluid that can be moved in any direction by applying a magnetic field. The magnetically controlled battery concept could be especially useful for flow batteries, where it could eliminate the need for the pumps that are typically required for moving the electrolyte from an external storage tank to the inside of a power stack to provide electricity. Flow batteries are being actively researched as large-scale energy storage devices for power grids, where they could store energy captured by intermittent alternative energy sources such as wind and solar.

The researchers, led by Yi Cui, Professor at Stanford University, have published a paper on the new magnetically controlled battery in a recent issue of Nano Letters.

“The greatest significance of our work lies in the innovative idea of using a magnetic field to control and enhance the mass and electron transport in a battery system,” lead author Weiyang Li, previously at Stanford University and now at Dartmouth College, told Phys.org.

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My take on the MIT study.

Routine human missions to Mars would be much more efficient if they first swung by Earth’s Moon to pick up fuel for the trip, a new MIT strategic engineering study concludes. NASA’s 90’s-era mantra of “Back to the Moon and on to Mars” really does make sense, a new paper published in the Journal of Spacecraft and Rockets notes.

The idea is that a crewed mission to Mars would greatly save on fuel and launch costs if it first made an interplanetary pit stop at a space-based depot to pick up its needed fuel. In this case, such a depot would optimally be placed at the Earth-Moon Lagrange Point 2 (EML2), a point of gravitational equilibrium lying beyond the Moon’s far side.

The paper’s authors conclude that such a stop would reduce the mission’s initial launch mass into low earth orbit by as much as 68%.

Continue reading “Why An Interplanetary Fuel Stop Makes Sense For Human Missions To Mars” | >

While the US military continues to develop new and awesome ways of blowing aerial drones to smithereens, not many of these systems can easily be adapted to use in the civilian realm. That’s why Battelle has developed the DroneDefender, a shoulder-mounted rifle that knocks UAVs offline with a barrage of radio waves.

“It can help us in numerous settings, from the White House lawn to bases and embassies overseas; from prisons and schools to historic sites,” Alex Morrow, technical director on the project, said in a statement. “It easily and reliably neutralizes the threat.” The weapon weighs roughly 10 pounds and can target drones up to 400 meters away. When the trigger is pulled, the gun emits a blast of electromagnetic energy tuned to the most common GPS and ISM frequencies, safely disabling the drone and preventing it from accepting any additional commands from its operator. This is especially helpful if the drone is equipped with an improvised explosive device.

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“The world is facing some huge problems. There’s a lot of talk about how to solve them. But talk doesn’t reduce pollution, or grow food, or heal the sick. That takes doing. This film is the story about a group of doers, the elegantly simple inventions they have made to change the lives of billions of people, and the unconventional billionaire spearheading the project.”

A team of physicists has proposed a way of teleporting energy over long distances. The technique, which is purely theoretical at this point, takes advantage of the strange quantum phenomenon of entanglement where two particles share the same existence.

The researchers, who work out of Tohoku University in Japan, and led by Masahiro Hotta,describe their proposal in the latest edition of Physical Review A. Their system exploits properties of squeezed light or vacuum states that should allow for the teleportation of information about an energy state. In turn, this teleported quantum energy could be made useable.

Unlike teleportation schemes as portrayed in Star Trek or The Fly, this type of teleportation describes entanglement experiments in which two entangled particles are joined despite no apparent connection between them. When a change happens to one particle, the same change happens to the other. Hence, the impression of teleportation. Physicists have conducted experiments using light, matter, and now, energy.

According to Hotta, a measurement on the first particle injects quantum energy into the system. Then, by carefully choosing the measurement to do on the second particle, it is possible to extract the original energy.

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What is ideally needed is a bulk electricity storage device which is scalable to gig watt, which is reliable, efficient and economically viable, but more importantly, it should be environmentally friendly. One such promising technology on the horizon with a capability to compete with pumped hydro and gas turbines for peaking and immediate power generation is storing energy by gravity.

A gravity storage system consist of a pair of two deep shafts one large, and the other smaller in diameter connected at the top and bottom, forming a closed formed circuit via a reversible pumpturbine, as seen in Figure 1. The shafts are filled with water, which acts as a medium for energy transfer, and the bigger shaft is fitted with a huge steel piston filled with reinforced rock and concrete. The whole device operates on the simple action of vertical motion of piston.

During the availability of surplus electricity, the reversible pumpturbine converts the grid power supplied by a dual purpose motorgenerator to potential energy, by pumping the water in the larger shaft to raise the heavy piston. At times of need, like during peak demand, this stored potential energy is converted back to electrical energy by allowing the piston to descend, which in the process energizes the water molecules to rotate the turbinepump blades, leading to power generation at the generatormotor end.

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