Friday, June 9, 2006

Super Plastic Both Attracts and Repels Water Technology Review: "A new, practical method for making surfaces with patterns of areas that strongly attract and strongly repel water could lead to a highly efficient method for capturing clean water. This versatile material could also find uses in fabricating new types of devices for medical tests and chemical synthesis. Scientists have reported numerous applications of water-attracting (superhydrophilic) and water-repelling (superhydrophobic) surfaces, including fog-free eyeglasses and windshields, and self-cleaning cloth and glass. Now a group of researchers in MIT's materials science and engineering department has combined those opposing characteristics on a single surface, by using a simple and versatile fabrication process... "Robert Cohen, Michael Rubner, and colleagues started by assembling a nano-structured film made of alternating layers of positively and negatively charged polymers and silica nanoparticles. The film's structure and a coating of waxy fluorinated silane cause water to bead on it, forming near-perfect spheres that easily roll off. To add the superhydrophilic regions (to which water droplets cling), the researchers applied a naturally hydrophilic polymer to selected areas. "In dry regions of the world, without easy access to clean water, such a material could be used for collecting water. In this application, the hydrophilic areas of the material would attract moisture in the air, collecting water drops that accumulate, until they spill over into the hydrophobic regions and roll into a collecting channel. Currently, in countries with limited access to clean water, the inhabitants typically use large polypropylene fiber meshes to harvest water from fog. The new technology 'would provide a more than tenfold increase in water capture compared to the inefficient nets that are used currently,' says Andrew Parker, a biologist at Oxford University and the Natural History Museum in London, who has studied the desert beetle that inspired the MIT work. If the new material 'could be added simply to the roofs of houses in areas subjected to desert fogs,' says Parker, 'then a water supply could be gained with little effort.' Rubner's lab is also taking the technique further. 'When we harvest water, we have chemistry built into the hydrophilic area so that it has an antibacterial agent to kill off bacteria and other things that cause harm,' Rubner says. This decontaminates the water as it accumulates so that the collected water is safe for use. Applying this technique, the researchers have been able to kill common harmful bacteria in four minutes, he says." Category: Colorado Water 7:35:53 AM     Preferred Options Storage Plan Officials from the rainy side of Colorado want their concerns considered in legislation that will create the Preferred Options Storage Plan, according to the Pueblo Chieftain. From the article, "Western Slope water interests want to address the economic, social and environmental impacts of water transfers if they are studied under a water storage bill for the Arkansas Valley. The Colorado River District has obtained the support of U.S. Rep. John Salazar in including impacts on areas where water has been exported in a sweeping study by the Southeastern Colorado Water Conservancy District. Salazar has suggested a study of the historic impacts of water projects under the Preferred Storage Options Plan, which would study enlargement of Lake Pueblo and Turquoise Lake. PSOP, stalled for five years in Congress, also would formalize the Bureau of Reclamation's authority to lease storage space to Aurora, a city of more than 300,000 east of Denver that moves water it owns in Crowley and Otero counties to Twin Lakes via exchanges. Aurora's water is pumped from Twin Lakes through the Homestake Pipeline and Otero Pumping Station. The Fryingpan-Arkansas Project diverts water from the Hunter-Fryingpan drainage area west of the Continental Divide into Turquoise Lake. The Colorado River District has expressed its concerns in the past, reaching an agreement with the Southeastern District in late 2004 on a different version of PSOP... "[Chris Treese, external affairs manager of the Colorado River District] asked to include Western Slope points of diversion and affected downstream areas in the PSOP legislation. He said he has discussed changes with Salazar's office, hitting several nerves that already have stalled the bill. Last month, Miskel predicted the Western Slope diversions would be raised." Category: Colorado Water 6:04:54 AM

© Copyright 2006 John Orr. Last update: 12/29/06; 11:46:31 AM.