Science Briefs

September 22, 2013 

Best settings for tidal-sail generators

In the search to find new sources of clean, low-cost power, slow and steady might win the race – slow-moving currents and tides, that is. Just as wind turbines tap into the energy of flowing air to generate electricity, hydrokinetic devices produce power from flowing water.

In a paper appearing in the American Institute of Physics’ Journal of Renewable and Sustainable Energy, a team led by Spain’s University of Malaga performed a computer simulation to determine the optimum configuration of one such system to enable it to extract the maximum amount of energy from any given current.

The system, developed in Norway, consists of a string of submerged blades or sails, connected via wire ropes and angled into the oncoming current.

The current generates large lift forces in the sails. As they are pushed through a continuous loop, they drive a generator to produce electricity.

The researchers found the maximum amount of power could be generated using blades positioned at about a 79-degree angle relative to the oncoming current, and which move about one and half a times as fast as the current. American Institute of Physics

Live webcam coaching helps struggling readers

A literacy webcam coaching strategy, developed by researchers at UNC-Chapel Hill, has been shown to significantly help struggling kindergarten and first-grade readers in rural classrooms keep pace with their peers. Targeted Reading Intervention webcam coaching also achieves this at low cost by eliminating geographic barriers and reducing the need for special education.

TRI webcams use in-place classroom teachers to deliver enriched instruction. Literacy coaches, who can be located far off-site, provide state-of-the-art coaching to teachers in classrooms as they work in 15-minute one-on-one sessions with the youngsters.

Teachers use laptops with webcams so that they can see and hear the off-site coaches’ real-time feedback and the coaches can see and hear the teachers as they work with children.

The study was published in the Journal of Educational Psychology. UNC News

Artwork’s ‘health’ diagnosed

Scientists and conservators have developed a new method to diagnose painting canvases from the back, without disturbing a single fiber, to see whether they can withstand the stress of handling and travel.

Scientists assessed the “health” of 12 paintings by surrealist Salvador Dalí. Canvases degrade with time because of acidity and environmental conditions. Once a canvas is brittle, expensive conservation is required.

The method is similar to the way doctors measure blood sugar without needles. By shining invisible near-infrared light on the canvas through fiber optics, scientists obtained information about the “health” of the painting from the reflection of the light. Since canvas is the carrier of paint, any tears or other mechanical degradation could lead to loss of the image if the canvas is too brittle. Dali’s canvases were shown to be in good condition.

The method was developed by collaborating researchers and conservators at five European universities and The British Library. The research is published in the Royal Society of Chemistry journal Analytical Methods. ucl.ac.uk

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