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Biofuel’s Water Problem

Irrigating biofuel crops on a grand scale would be disastrous

2 min read
Photo: Jeremy Nixon/Alamy
Photo: Jeremy Nixon/Alamy

The great advantage of biofuel over petroleum is that the sources of biofuel are so widely available. The geologic fates may not have endowed your corner of the world with oil or gas deposits, but just about everyone can grow plants to make fuel. Unfortunately, some of the places these crops are grown require irrigation, and when water enters the equation, biofuels are a lot less attractive than the stuff they’re replacing.

Take soybeans. According to Carey W. King and Michael E. Webber of the University of Texas at Austin, the processing required to turn soybeans into biodiesel requires negligible water. But if you can’t depend on rain, raising the crop in the first place takes buckets. On average in the United States, 28 liters of irrigation water are needed to produce enough soybeans to propel an average vehicle 1 kilometer (12 gallons of water consumed per mile driven). Ethanol produced from corn grown on irrigated fields is almost as bad. Driving a typical flexible-fuel vehicle on E85 (85 percent ethanol fuel) produced from irrigated cornfields consumes about 26 L/km on average, assuming both the corn’s seed and stalks are transformed into ethanol.

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Quantum Computing for Dummies

New guide helps beginners run quantum algorithms on IBM's quantum computers over the cloud

3 min read
An image of the inside of an IBM quantum computer.
IBM

Quantum computers may one day rapidly find solutions to problems no regular computer might ever hope to solve, but there are vanishingly few quantum programmers when compared with the number of conventional programmers in the world. Now a new beginner's guide aims to walk would-be quantum programmers through the implementation of quantum algorithms over the cloud on IBM's publicly available quantum computers.

Whereas classical computers switch transistors either on or off to symbolize data as ones or zeroes, quantum computers use quantum bits, or "qubits," which because of the peculiar nature of quantum physics can exist in a state called superposition where they are both 1 and 0 at the same time. This essentially lets each qubit perform two calculations at once. The more qubits are quantum-mechanically linked, or entangled (see our explainer), within a quantum computer, the greater its computational power can grow, in an exponential fashion.

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This Wearable Neck Patch Can Diagnose Concussions

Self-powered sensors convert neck strain into electrical pulses to detect head trauma in athletes

4 min read
image of back of man's head and shoulders with a patch taped to his lower neck; right image is a time lapse image of a man's head extending far forward and back, simulating a case of whiplash

The prototype patch in this research is shown in (a) on the left; on the right (b) is the kind of head rotation that can yield an electrical response from the patch.

Juan Pastrana

Nelson Sepúlveda was sitting in the stands at Spartan Stadium, watching his hometown Michigan State players bash heads with their cross-state football rivals from the University of Michigan, when he had a scientific epiphany.

Perhaps the nanotechnologies he had been working on for years—paper-thin devices known as ferroelectret nanogenerators that convert mechanical energy into electrical energy—could help save these athletes from the ravages of traumatic brain injury.

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A Multiphysics Approach to Designing Fuel Cells for Electric Vehicles

White paper on fuel cell modeling and simulation

1 min read
Comsol Logo
Comsol

Fuel cell electric vehicles (FCEVs) often reach higher energy density and exhibit greater efficiency than battery EVs; however, they also have high manufacturing costs, limited service life, and relatively low power density.

Modeling and simulation can improve fuel cell design and optimize EV performance. Learn more in this white paper.