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Category: sustainability – Page 620

Solar power is making huge strides as a reliable, renewable energy source, but there’s still a lot of untapped potential in terms of the efficiency of photovoltaic cells and what happens at night and during inclement weather. Now a solution has been put forward in the form of producing energy from raindrops.

Key to the new process is graphene: a ‘wonder’ material we’ve heard plenty about before. Because raindrops are not made up of pure water, and contain various salts that split up into positive and negative ions, a team from the Ocean University of China in Qingdao thinks we can harness power via a simple chemical reaction. Specifically, they want to use graphene sheets to separate the positively charged ions in rain (including sodium, calcium, and ammonium) and in turn generate electricity.

Early tests, using slightly salty water to simulate rain, have been promising: the researchers were able to generate hundreds of microvolts and achieve a respectable 6.53 percent solar-to-electric conversion efficiency from their customised solar panel.

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Improving light-sensing devices with Q-Dots.

Harnessing the power of the sun and creating light-harvesting or light-sensing devices requires a material that both absorbs light efficiently and converts the energy to highly mobile electrical current. Finding the ideal mix of properties in a single material is a challenge, so scientists have been experimenting with ways to combine different materials to create “hybrids” with enhanced features.

In two just-published papers, scientists from the U.S. Department of Energy’s Brookhaven National Laboratory, Stony Brook University, and the University of Nebraska describe one such approach that combines the excellent light-harvesting properties of quantum dots with the tunable electrical conductivity of a layered tin disulfide semiconductor. The hybrid material exhibited enhanced light-harvesting properties through the absorption of light by the quantum dots and their energy transfer to tin disulfide, both in laboratory tests and when incorporated into electronic devices. The research paves the way for using these materials in optoelectronic applications such as energy-harvesting photovoltaics, light sensors, and light emitting diodes (LEDs).

Quantum Dots

Continue reading “Quantum dots enhance light-to-current conversion in layered metal dichalcogenide semiconductors” | >

Got a grand burning a hole in your pocket? You could get a new laptop — or you could send this tiny, palm-sized satellite to space. That’s what a team of engineers at Arizona State hope, anyway: their “FemtoSats” are meant to be as cheap a space-bound platform as has ever been devised.

At just 3cm per side and 35 grams (that’s about 1.2 inches and 0.077 pounds, dogs of the Imperial system), the SunCube 1F is the prototype FemtoSat. It’s powered by a salvaged scrap of solar panel (they don’t make them small enough off the shelf), the tiny unit includes propulsion, imaging, communication, and data collection.

“The design standard bootstraps from the Cal Poly CubeSat standard and is extensible, allowing major customization,” wrote Jekan Thanga, the ASU assistant professor who heads up the project, in an email to TechCrunch.

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“Virtually all new fossil fuel-burning power-generation capacity will end up “stranded”. This is the argument of a paper by academics at Oxford university. We have grown used to the idea that it will be impossible to burn a large portion of estimated reserves of fossil fuels if the likely rise in global mean temperatures is to be kept below 2C. But fuels are not the only assets that might be stranded. A similar logic can be applied to parts of the capital stock.”

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One week after Elon Musk unveiled the Tesla Model 3, the company’s first mass-market car, hundreds of thousands of people have paid $1,000 to reserve the car despite its expected late-2017 launch.

That reservation figure totals to $14 billion (theoretical dollars) in sales, or 325,000 cars, with one big caveat: With only $1,000 down, some — perhaps many — of these orders will inevitably be adjusted or canceled over the next few years. In any event, that’s $325 million paid in preorders to date for a car that basically doesn’t exist yet.

Over 325k cars or ~$14B in preorders in first week. Only 5% ordered max of two, suggesting low levels of speculation.

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A new kind of nanoscale rectenna (half antenna and half rectifier) can convert solar and infrared into electricity, plus be tuned to nearly any other frequency as a detector.

Right now efficiency is only one percent, but professor Baratunde Cola and colleagues at the Georgia Institute of Technology (Georgia Tech, Atlanta) convincingly argue that they can achieve 40 percent broad spectrum efficiency (double that of silicon and more even than multi-junction gallium arsenide) at a one-tenth of the cost of conventional solar cells (and with an upper limit of 90 percent efficiency for single wavelength conversion).

It is well suited for mass production, according to Cola. It works by growing fields of carbon nanotubes vertically, the length of which roughly matches the wavelength of the energy source (one micron for solar), capping the carbon nanotubes with an insulating dielectric (aluminum oxide on the tethered end of the nanotube bundles), then growing a low-work function metal (calcium/aluminum) on the dielectric and voila–a rectenna with a two electron-volt potential that collects sunlight and converts it to direct current (DC).

“Our process uses three simple steps: grow a large array of nanotube bundles vertically; coat one end with dielectric; then deposit another layer of metal,” Cola told EE Times. “In effect we are using one end of the nanotube as a part of a super-fast metal-insulator-metal tunnel diode, making mass production potentially very inexpensive up to 10-times cheaper than crystalline silicon cells.”

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Eco handshake.

“Misinterpreting signals to make them consistent with a pre-determined outcome is, psychologists tell us, a common phenomenon in human nature. Unfortunately, it is also a frequent dynamic in modern financial markets, particularly when it comes to sustainability.”

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SpaceX started with a plan to send mice to Mars. It got crazier from there.

In late October 2001, Elon Musk went to Moscow to buy an intercontinental ballistic missile. He brought along Jim Cantrell, a kind of international aerospace supplies fixer, and Adeo Ressi, his best friend from Penn. Although Musk had tens of millions in the bank, he was trying to get a rocket on the cheap. They flew coach, and they were planning to buy a refurbished missile, not a new one. Musk figured it would be a good vehicle for sending a plant or some mice to Mars.

Ressi, a gangly eccentric, had been thinking a lot about whether his best friend had started to lose his mind, and he’d been doing his best to discourage the project. He peppered Musk with links to video montages of Russian, European, and American rockets exploding. He staged interventions, bringing Musk’s friends together to talk him out of wasting his money. None of it worked. Musk remained committed to funding a grand, inspirational spectacle in space and would spend all of his fortune to do it. And so Ressi went to Russia to contain Musk as best as he could. “Adeo would call me to the side and say, ‘What Elon is doing is insane. A philanthropic gesture? That’s crazy,’” said Cantrell. “He was seriously worried.”

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