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Crystal Sieves
Now, however, a team of chemists, engineers and mathematicians, using some of the most advanced microscopes in the research arsenal, has uncovered new details for the step-by-step evolution from molecular soup to carefully engineered zeolite crystal. With this knowledge, laboratories may be able to use targeted methods to create zeolites with precisely the crystal sizes and shapes demanded by molecule-specific applications such as chemical sensing. University of Minnesota chemical engineer Michael Tsapatsis, graduate student and lead author Tracy Davis, and their colleagues report their findings Apr. 17, 2006, online in Nature Materials. The research was supported by several National Science Foundation (NSF) grants from across three Divisions. Zeolites are familiar to consumers as, say, the white crystals in aquarium filters, or the ion-exchanging workhorses in advanced detergents. But their real economic impact is behind the scenes, where they are critical for extracting various chemical components out of petroleum and its byproducts on an industrial scale......... Posted by: Sarah Permalink Source New student-designed system tracks firefighters, special forces
A group of University of Florida engineering students has designed a system to locate, track and communicate with special forces troops or firefighters in remote areas where no cell towers or other communications infrastructure exist. The system allows soldiers or firefighters to pinpoint their own and their comrades' whereabouts on digital maps displayed on handheld personal digital assistants. It can transmit this information via satellite phone, making it available to Internet-connected commanders or observers anywhere in the world. It even gives users the option of punching a panic button or sending text messages such as "need more water," "pull me out," or simply "help!". "It's live and it's in real time," said UF electrical and computer engineering senior Rolando Estrella. Estrella is among seven UF engineering seniors who spent the semester creating the system as part of the College of Engineering's Integrated Product & Process Design program. The 11-year-old program's goal is to assist corporations, small businesses and government agencies with engineering problems while giving engineering students practical experience working on real-world projects......... Posted by: Kevin Permalink Source Frictionless Motion In Water
Each rotating cyanide ion creates a shock wave that throws back the surrounding water molecules, allowing it to spin for a time with essentially no friction.
Credit: Nicolle Rager-Fuller, National Science Foundation
Indeed, the technique gives chemists a potential new tool to influence how a reaction progresses, as one way to do that is to isolate an interacting molecule from its surroundings. In experiments they describe in a recent issue of the journal Science, the chemists start with a water sample containing cyanide ions, each of which is basically a molecular stick with a carbon atom at one end and a nitrogen atom at the other. Then they spin the sticks to with a laser. Within the first quarter-turn, each rotating cyanide ion creates a shock wave that throws back the surrounding water molecules. (Bradforth, who is part of the study team, likens the phenomenon to a passenger swinging a suitcase in a crowded airport terminal, minus the real-life bruises and hurt feelings.) Inside the resulting bubble, the molecule will then continue whirling for a time with essentially no friction......... Posted by: Sarah Permalink Source Motor To Single-molecule Car
This animation depicts two motorized nanocars on a gold surface. The nanocar consists of a rigid chassis and four alkyne axles that spin freely and swivel independently of one another.....
The research is reported in the April 13 issue of the journal Organic Letters. "We want to construct things from the bottom up, one molecule at a time, in much the same way that biological cells use enzymes to assemble proteins and other supermolecules," said lead researcher James M. Tour, the Chao Professor of Chemistry, professor of mechanical engineering and materials science and professor of computer science. "Everything that's produced through biology - from the tallest redwood to largest whale - is built one molecule at a time. Nanocars and other synthetic transporters may prove to be a suitable alternative for bottom-up systems where biological methods aren't practical." The motorized model of the nanocar is powered by light. Its rotating motor, a molecular framework that was developed by Ben L. Feringa at the University of Groningen in the Netherlands, was modified by Tour's group so that it would attach in-line with the nanocar's chassis. When light strikes the motor, it rotates in one direction, pushing the car along like a paddlewheel. The first nanocar research paper, published the journal Nano Letters last October, was the most-accessed article from all American Chemical Society journals in 2005. That paper was co-authored by Kevin Kelly, assistant professor of electrical and computer engineering......... Posted by: Kevin Permalink Source Glasses That Hear
Approximately 1,265,000 people in the Netherlands over the age of 60 are hearing impaired. Of these, half 22% (or around 275,000 people) use a hearing aid, but it is not always possible to hear others well if there is surrounding noise. Many hearing aids intensify sounds from all directions. The result is that people hear noise, but not the people they are speaking to. Because people have such difficulty understanding what others are saying, many people - in spite of their hearing aid - have less social contact with others or must retire from their jobs earlier than desired. The hearing-glasses can provide a solution to this problem, say the experts and users who have tried and tested the Varibel. The Varibel cannot be compared to traditional hearing aids. In each leg of the glass' frame there is a row of four tiny, interconnected microphones, which selectively intensify the sounds that come from the front, while dampening the surrounding noise. The result is a directional sensitivity of +8.2 dB. In comparison, regular hearing aids have a maximum sensitivity of +4 dB. With this solution, the user can separate the desired sounds from the undesired background noise. Dr. Cor Stengs, ENT specialist involved in the clinical tests, said of the Varibel: "Practical experience with the hearing-glasses supports the theoretical claims that the ability to understand speech is much better. There is a significant improvement in the sound quality"......... Posted by: Kevin Permalink Source changing semiconductors into flexible membranes
Led by materials science and engineering graduate student Michelle Roberts, the team reports in the April 9 issue of Nature Materials that the freed membranes, just tens of nanometers thick, retain all the properties of silicon in wafer form. Yet, the nanomembranes are flexible, and by varying the thicknesses of the silicon and silicon-germanium layers composing them, researchers can make membrane shapes ranging from flat to curved to tubular. Most importantly, the technique stretches the nanomembranes in a predictable and easily controlled manner, says materials science and engineering professor Max Lagally, who is Roberts' advisor. In silicon that is stretched, or under tensile strain, current flows faster-a fact engineers already exploit to help control silicon's conductivity and produce speedier electronics. Strain also becomes important whenever different materials are integrated. The new technique makes tuning the strain of materials simpler, while avoiding the defects that normally result. In addition, Lagally says: "We're no longer held to a rigid rock of material. We now have the ability to transfer the membranes to anything we want. So, there are some really novel things we can do."........ Posted by: Kevin Permalink Source Vulnerabilities of Rapidly Growing Internet Phone
The three-year project will investigate voice spam prevention (VoIP phone systems can be spammed like email), attacks on networks and Internet resources that render them unavailable (denial of service), quality of service, and 911 service dependability. The unique test bed will also be used to discover security holes arising from operating VoIP with conventional phone networks. "Proactively securing the next-generation infrastructure for voice communications is critical for us all," said UNT's Ram Dantu, who leads the project. "Our research will identify vulnerabilities in the technology and establish solutions--before damage is done". VoIP allows users with a computer and a standard Internet connection to make toll-free calls anywhere in the world. It also handles video and instant messaging. Companies such as Vonage and AT&T are aggressively deploying the technology, and one study predicts some 24 million U.S. households will be using VoIP by 2008. Government agencies are already implementing strategies to use VoIP-based systems......... Posted by: Kevin Permalink Source Housing Designed With Louisiana In Mind
MIT's Special Interest Group in Urban Settlement has developed a modular unit house that accommodates different family sizes, is tailored to bayou culture and stands on flood-resistant stilts. Illustration / Non Arkaraprasertkul
Reinhard Goethert, principal research associate in architecture, is director of the Special Interest Group in Urban Settlement (SIGUS) in architecture and planning, a group working on a housing design and building initiative in the bayou region near Houma, southwest of New Orleans, where hurricane floods destroyed a number of homes last summer. The group will provide expertise in design, structural, lifting and environmental issues, family issues and volunteer management. "Managing volunteers in a bayou building project means doing a lot of teaching," Goethert said. SIGUS is working jointly with Oxfam America and the Terrebonne Readiness and Assistance Coalition (TRAC), a Louisiana-based nongovernmental organization, on LIFT House, a housing design and building initiative. Goethert, who teaches courses on urbanization, design and housing in developing countries, has developed settlement housing programs throughout the world, most recently in areas of Indonesia destroyed by the tsunami. He has received a United Nations Habitat Scroll of Honor for his "outstanding contributions in community action". Goethert and Joel Turkel, lecturer in architecture, are advising the MIT SIGUS team, which includes three architecture students, two urban planning students and three advisors from the department's Building Technology Section......... Posted by: Kevin Permalink Source Kids' TV Time And Consumerism
"It's called the 'nag factor,'" said Lisa Chamberlain, MD, MPH, Packard Children's researcher and clinical instructor at the medical school, "and it's very effective". What's more, the correlation between increased screen time and subsequent requests for toys and junk food held true for over a period of 20 months. Chamberlain warns that, if left unchecked, increasing amounts of screen time for children could foster a rise in obesity and consumerismthat will reverberate for decades. She is the lead author of the research, which would be published in the recent issue of the Archives of Pediatrics & Adolescent Medicine. "We're proving what marketers have known for years," said Chamberlain. "Kids have discretionary income of their own, and they also have a lot of influence of how their parents spend the family's money". Chamberlain collaborated with pediatric researcher Thomas Robinson, MD, for the study. Robinson is well-known for his investigations into the links between television viewing and obesity, violence and test scores. He is also the director of Packard Children's Center for Healthy Weight, and an associate professor of pediatrics at Stanford's School of Medicine......... Posted by: Kevin Permalink Source Supercomputer Maps One Million Atoms of a Complete Virus
Led by Klaus Schulten at the University of Illinois at Urbana-Champaign, the team tapped the high-performance power of the National Center for Supercomputing Applications (NCSA) processors to accomplish the task. Still, it took about 100 days to generate just 50 nanoseconds of virus activity. Schulten says it would have taken the average desktop computer 35 years to come up with the results. The simulation revealed key physical properties of satellite tobacco mosaic virus, a very simple, plant-infecting virus. Ultimately, researchers will generate longer simulations from bigger biological entities, but to do so, they need the next generation of supercomputers, the so-called "petascale high-performance computing systems." The National Science Foundation (NSF) is currently devising a national strategy for petascale computing to give researchers and engineers the resources needed to tackle their most computationally intensive research problems......... Posted by: Kevin Permalink Source |
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