Max Hyre - Slashdot User

Comment Curious licensing (Score 1) 9

by Max Hyre on Sunday January 18, 2015 @05:04PM (#48846307) Attached to: New MATLAB alternative is dirt-cheap and open source

Submission + - Shanghai Company 3D Prints 6-Story Apartment Building and an Incredible Home (3dprint.com)

Submitted by ErnieKey on Sunday January 18, 2015 @03:47PM

Submission + - Climate Change, the Fermi Paradox, and the Fate Of Our Planet

Submitted by HughPickens.com on Sunday January 18, 2015 @01:02PM

HughPickens.com writes: Astrophysicist Adam Frank has an interesting article in the NYT postulating one answer to the Fermi paradox — that human evolution into a globe-spanning industrial culture is forcing us through the narrow bottleneck of a sustainability crisis and that climate change is fate and nothing we do today matters because civilization inevitably leads to catastrophic planetary changes. According to Frank, our current sustainability crisis may be neither politically contingent nor unique, but a natural consequence of laws governing how planets and life of any kind, anywhere, must interact. Some excerpts:
The defining feature of a technological civilization is the capacity to intensively “harvest” energy. But the basic physics of energy, heat and work known as thermodynamics tell us that waste, or what we physicists call entropy, must be generated and dumped back into the environment in the process. Human civilization currently harvests around 100 billion megawatt hours of energy each year and dumps 36 billion tons of carbon dioxide into the planetary system, which is why the atmosphere is holding more heat and the oceans are acidifying.

All forms of intensive energy-harvesting will have feedbacks, even if some are more powerful than others. A study by scientists at the Max Planck Institute in Jena, Germany, found that extracting energy from wind power on a huge scale can cause its own global climate consequences. When it comes to building world-girdling civilizations, there are no planetary free lunches.

By studying these nearby planets, we’ve discovered general rules for both climate and climate change (PDF). These rules, based in physics and chemistry, must apply to any species, anywhere, taking up energy-harvesting and civilization-building in a big way. For example, any species climbing up the technological ladder by harvesting energy through combustion must alter the chemical makeup of its atmosphere to some degree. Combustion always produces chemical byproducts, and those byproducts can’t just disappear.

As we describe in a recent paper, using what’s already known about planets and life, it is now possible to create a broad program for modeling co-evolving “trajectories” for technological species and their planets. Depending on initial conditions and choices made by the species (such as the mode of energy harvesting), some trajectories will lead to an unrecoverable sustainability crisis and eventual population collapse. Others, however, may lead to long-lived, sustainable civilizations.

Submission + - This Temporary Tattoo Measures Glucose Levels In Blood (thescienceworld.com)

Submitted by Diggester on Sunday January 18, 2015 @12:40PM

Submission + - Laser that is powered by one electron at a time (princeton.edu) 1

Submitted by Taco Cowboy on Sunday January 18, 2015 @12:48AM

Taco Cowboy writes: Princeton University researchers have built a rice grain-sized laser powered by single electrons tunneling through artificial atoms known as quantum dots. The tiny microwave laser, or "maser," is a demonstration of the fundamental interactions between light and moving electrons

The researchers built the device — which uses about one-billionth the electric current needed to power a hair dryer — while exploring how to use quantum dots, which are bits of semiconductor material that act like single atoms, as components for quantum computers

The device demonstrates a major step forward for efforts to build quantum-computing systems out of semiconductor materials, according to co-author and collaborator Jacob Taylor, an adjunct assistant professor at the Joint Quantum Institute, University of Maryland-National Institute of Standards and Technology. "I consider this to be a really important result for our long-term goal, which is entanglement between quantum bits in semiconductor-based devices" Taylor said

The researchers fabricated the double quantum dots from extremely thin nanowires (about 50 nanometers, or a billionth of a meter, in diameter) made of a semiconductor material called indium arsenide. They patterned the indium arsenide wires over other even smaller metal wires that act as gate electrodes, which control the energy levels in the dots

To construct the maser, they placed the two double dots about 6 millimeters apart in a cavity made of a superconducting material, niobium "This is the first time that the team at Princeton has demonstrated that there is a connection between two double quantum dots separated by nearly a centimeter, a substantial distance" Taylor said

When the device was switched on, electrons flowed single-file through each double quantum dot, causing them to emit photons in the microwave region of the spectrum. These photons then bounced off mirrors at each end of the cavity to build into a coherent beam of microwave light

One advantage of the new maser is that the energy levels inside the dots can be fine-tuned to produce light at other frequencies, which cannot be done with other semiconductor lasers in which the frequency is fixed during manufacturing, Petta said. The larger the energy difference between the two levels, the higher the frequency of light emitted

"In this paper the researchers dig down deep into the fundamental interaction between light and the moving electron" Gmachl said. "The double quantum dot allows them full control over the motion of even a single electron, and in return they show how the coherent microwave field is created and amplified. Learning to control these fundamental light-matter interaction processes will help in the future development of light sources"