August 24, 2009, 10:33 PM CT

Lower-cost solar cells to be printed like newspaper

Solar cells could soon be produced more cheaply using nanoparticle "inks" that allow them to be printed like newspaper or painted onto the sides of buildings or rooftops to absorb electricity-producing sunlight.

Brian Korgel, a University of Texas at Austin chemical engineer, is hoping to cut costs to one-tenth of their current price by replacing the standard manufacturing process for solar cells - gas-phase deposition in a vacuum chamber, which requires high temperatures and is relatively expensive.

"That's essentially what's needed to make solar-cell technology and photovoltaics widely adopted," Korgel said. "The sun provides a nearly unlimited energy resource, but existing solar energy harvesting technologies are prohibitively expensive and cannot compete with fossil fuels".

For the past two years, Korgel and his team have been working on this low-cost, nanomaterials solution to photovoltaics - or solar cell - manufacturing. Korgel is collaborating with professors Al Bard and Paul Barbara, both of the Department of Chemistry and Biochemistry, and Professor Ananth Dodabalapur of the Electrical and Computer Engineering Department. They recently showed proof-of-concept in a recent issue of Journal of the American Chemical Society.

The inks could be printed on a roll-to-roll printing process on a plastic substrate or stainless steel. And the prospect of being able to paint the "inks" onto a rooftop or building is not far-fetched......... Posted by: Kevin      Read more         Source

August 20, 2009, 6:50 AM CT

Flying by the Skin of Our Teeth

It's been a mystery: how can our teeth withstand such an enormous amount of pressure, over a number of years, when tooth enamel is only about as strong as glass? A newly released study by Prof. Herzl Chai of Tel Aviv University's School of Mechanical Engineering and colleagues at the National Institute of Standards and Technology and George Washington University gives the answer.

The scientists applied varying degrees of mechanical pressure to hundreds of extracted teeth, and studied what occurred on the surface and deep inside them. The study, reported in the May 5, 2009, issue of the Proceedings of the National Academy of Science, shows that it is the highly-sophisticated structure of our teeth that keeps them in one piece - and that structure holds promising clues for aerospace engineers as they build the aircraft and space vehicles of the future.

"Teeth are made from an extremely sophisticated composite material which reacts in an extraordinary way under pressure," says Prof. Chai. "Teeth exhibit graded mechanical properties and a cathedral-like geometry, and over time they develop a network of micro-cracks which help diffuse stress. This, and the tooth's built-in ability to heal the micro-cracks over time, prevents it from fracturing into large pieces when we eat hard food, like nuts"......... Posted by: Kevin      Read more         Source

August 20, 2009, 6:38 AM CT

Climate change could deepen poverty

Urban workers could suffer most from climate change as the cost of food drives them into poverty, as per a newly released study that quantifies the effects of climate on the world's poor populations.

A team led by Purdue University scientists examined the potential economic influence of adverse climate events, such as heat waves, drought and heavy rains, on those in 16 developing countries. Urban workers in Bangladesh, Mexico and Zambia were found to be the most at risk.

"Extreme weather affects agricultural productivity and can raise the price of staple foods, such as grains, that are important to poor households in developing countries," said Noah Diffenbaugh, the associate professor of earth and atmospheric sciences and interim director of Purdue's Climate Change Research Center who co-led the study. "Studies have shown global warming will likely increase the frequency and intensity of heat waves, drought and floods in a number of areas. It is important to understand which socioeconomic groups and countries could see changes in poverty rates in order to make informed policy decisions".

The team used data from the late 20th century and projections for the late 21st century to develop a framework that examined extreme climate events, comparable shocks to grain production and the impact on the number of impoverished people in each country......... Posted by: Tyler      Read more         Source

August 19, 2009, 6:58 AM CT

Nuclear fusion research key to advancing computer chips

Researchers are adapting the same methods used in fusion-energy research to create extremely thin plasma beams for a new class of "nanolithography" mandatory to make future computer chips.

Current technology uses ultraviolet light to create the fine features in computer chips in a process called photolithography, which involves projecting the image of a mask onto a light-sensitive material, then chemically etching the resulting pattern.

New nanolithography will be needed to continue advances in computer technology and to extend Moore's law, an unofficial rule stating that the number of transistors on integrated circuits, or chips, doubles about every 18 months.

"We can't make devices much smaller using conventional lithography, so we have to find ways of creating beams having more narrow wavelengths," said Ahmed Hassanein, the Paul L. Wattelet Professor of Nuclear Engineering and head of Purdue's School of Nuclear Engineering.

The new plasma-based lithography under development generates "extreme ultraviolet" light having a wavelength of 13.5 nanometers, less than one-tenth the size of current lithography, Hassanein said.

Nuclear engineers and researchers at Purdue and the U.S. Department of Energy's Argonne National Laboratory are working to improve the efficiency of two techniques for producing the plasma: One approach uses a laser and the other "discharge-produced" method uses an electric current......... Posted by: Kevin      Read more         Source

August 18, 2009, 11:05 PM CT

Scientists' strategic reading of research

The revolution in scientific publishing that has been promised since the 1980s is finally about to take place, as per two University of Illinois experts in information science.

Allen H. Renear and Carole L. Palmer, professors of library and information science at Illinois, say that as techniques originally designed to organize and share scientific data are integrated into scientific publishing, scientists' long-standing practice of reading "strategically" will be dramatically enhanced.

"Eventhough it's natural to believe that researchers search online to find individual articles to read, that isn't commonly what's going on," Renear said. "Scientists actually try to avoid reading as much as possible, relying instead on indexing, citations and peer recommendations as indicators of scientific relevance".

"Researchers skim journal articles to discover valuable information. They scan for terminology, segments, diagrams and summaries of particular interest. But they don't read individual articles left-to-right, top-to-bottom".

As the quantity of information that must be covered grows rapidly, Renear says efficient strategic reading becomes increasingly critical in scientific work.

In today's electronic environment, powerful new tools are emerging that support strategic reading, allowing researchers to work with large numbers of articles simultaneously without having to read them in their entirety......... Posted by: Kevin      Read more         Source

August 18, 2009, 7:53 AM CT

Scrubbing sulfur

The Department of Energy's Pacific Northwest National Laboratory has developed a reusable organic liquid that can pull harmful gases such as carbon dioxide or sulfur dioxide out of industrial emissions from power plants. The process could directly replace current methods and allow power plants to capture double the amount of harmful gases in a way that uses no water, less energy and saves money.

"Power plants could easily retrofit to use our process as a direct replacement for existing technology," said David Heldebrant, PNNL's lead research scientist for the project.

Harmful gases such as carbon dioxide or sulfur dioxide are called "acid gases". The new scrubbing process uses acid gas-binding organic liquids that contain no water and appear similar to oily compounds. These liquids capture the acid gases near room temperature. Researchers then heat the liquid to recover and dispose of the acid gases properly.

These recyclable liquids require much less energy to heat but can hold two times more harmful gases by weight than the current leading liquid absorbent used in power plants. It is a combination of water and monoethanolamine, a basic organic molecule that grabs the carbon dioxide.

PNNL's prior work with the all-organic liquids focused on pulling only carbon dioxide out of emissions from power plants. New work will show how the process can be applied to other acid gases such as sulfur dioxide......... Posted by: Sarah      Read more         Source

August 18, 2009, 7:50 AM CT

Clues To Caribbean's Earliest Inhabitants

A prehistoric water-filled cave in the Dominican Republic has become a "treasure trove" with the announcement by Indiana University archaeologists of the discovery of stone tools, a small primate skull in remarkable condition, and the claws, jawbone and other bones of several species of sloths.

The discoveries extend by thousands of years the scope of investigations led Charles Beeker, director of Academic Diving and Underwater Science Programs at IU Bloomington's School of Health, Physical Education and Recreation, and his interdisciplinary team of collaborators. The researchers' focus has been on the era a mere 500 years ago when the Old World and New World first met after Christopher Columbus stepped ashore in the Caribbean -- and on scintillating pirate lore. This rare find is expected to give insights into the earliest inhabitants of the Greater Antilles and the animals they encountered.

"To be honest, I couldn't believe my eyes as I viewed each of these astonishing discoveries underwater," Beeker said. "The virtually intact extinct faunal skeletons really amazed me, but what may prove to be a fire pit from the first human occupation of the island just seems too good to be true. But now that the lithics (stone tools) are authenticated, I can't wait to direct another underwater expedition into what may prove to become one of the most important prehistoric sites in all the Caribbean."........ Posted by: William      Read more         Source

August 16, 2009, 9:35 PM CT

Tough on stains, light on effort

Cleaning oily smears from kitchen countertops, mirrors, garage floors, and other surfaces with plain water rather than strong detergents or smelly solvents may seem like pure fantasy. But researchers in Indiana today describe what they believe to be a simple and effective state-of-the-art oil stain remover. They have developed a new coating for glass, plastics, and a range of other materials that would enable consumers to wipe away those pesky oils with plain water.

Their report at the 238th National Meeting of the American Chemical Society (ACS) points out that the same coatings can be added to common window cleaning sprays and used to prevent bathroom mirrors, automobile windshields and other surfaces from fogging up.

"You add water, and the oil just comes right off like magic," said Jeffrey Youngblood, Ph.D., lead researcher on the project. "These are eco-friendly coatings environmentally 'green' in the sense that they eliminate the need for harsh detergents and solvents in settings ranging from home kitchens to industrial machine shops that must contend with heavy oil spills".

The materials could be used in a range of consumer and industrial products, Youngblood said. They include household cleaners, easy-to-clean paints, water filters that separate water from oil, sealants for concrete floors and walls that repel oil in home garages and auto repair shops. In addition, anti-fog coatings could be used on windshields or eyewear, including everyday lenses and fog-free scuba masks......... Posted by: Kevin      Read more         Source

August 14, 2009, 7:14 AM CT

Evolution of human brainpower

New evidence that early modern humans used fire in southern Africa in a controlled way to increase the quality and efficiency of stone tools is changing how scientists understand the evolution of human behavior, and in particular, the evolution of human brain power.

Curtis Marean, a paleoanthropologist with the Institute of Human Origins at Arizona State University, and an international team of scientists with members from South Africa, England, Australia and France found 72,000-year-old, silcrete rocks that had been fired and flaked to make stone tools in a cave along the coast of the southern tip of Africa in Mossel Bay.

The finding indicates that humans' ability to solve complex problems may have occurred at the same time their modern genetic lineage appeared, rather than developing later as has been widely speculated......... Posted by: William      Read more         Source

August 13, 2009, 7:03 AM CT

Hurricane seasons are more active

For a number of Americans who live on the Atlantic coast, Andrew, Ivan and Katrina are more than just names--they are reminders of the devastating impact of cyclonic activity in the region during hurricane season. If it seems like hurricane seasons have been more active in recent years, you're on to something. As per a paper reported in the August 13 issue of Nature, the frequency and strength of these powerful storms has grown in recent decades.

"We are at levels now that are about as high as anything we have seen in the past 1,000 years," said Michael Mann, director of the Earth System Science Center at Pennsylvania State University and the main author of the paper. Mann and his collaborators, Jeffrey P. Donnelly of the Woods Hole Oceanographic Institution, Jonathan D. Woodruff of the University of Massachusetts and Zhihua Zhang of Pennsylvania State University examined sediment samples from across the North Atlantic coast and statistical models of historic hurricane activities.

Their analysis allowed them to measure the severity of hurricane seasons over the past 1,500 years. The sediment samples match up relatively well with the computer models, both of which show a period of high activity around 1,000 AD, followed by a lull in activity. This medieval peak rivals and possibly exceeds the level of activity seen in recent decades......... Posted by: Tyler      Read more         Source