Friday, August 31, 2007

Student Hopes To Break Human Land Speed Record Using Bullet Shaped Bicycle


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Science Daily — This October, Jerrod Bouchard will attempt to become the fastest college student to be propelled by his or her own power.
Bouchard, a senior in mechanical engineering at the University of Missouri-Rolla, will try to break the collegiate human-powered land speed record of 61.5 mph Oct 1-6 in Battle Mountain, Nev.
Seated in a bullet-shaped bicycle, Bouchard will be pedaling down a remote highway in Battle Mountain that is said to be one of the straightest, fastest and smoothest surfaces in the world.
Like a NASCAR driver, Bouchard is working with a talented crew to make sure his vehicle is sound. Members of the team include aerodynamics designer Andrew Sourk, a senior in aerospace engineering from St. Joseph, Mo.; team leader Craig George, a senior in electrical engineering from St. Joseph; and composite specialist Matt Brown, a senior in mechanical engineering from Rolla. Bouchard, who is from Camdenton, Mo., is the chief engineer.
Bouchard, Sourk, George and Brown are all members of UMR’s Human-Powered Vehicle Team, which won East Coast and West Coast championships in collegiate human-powered racing last spring. The Battle Mountain endeavor is a separate challenge that was born out of the larger team’s success.
Human-powered vehicles are recumbent bicycles with aerodynamic shells. All summer, the four-man UMR team has been designing and building a new vehicle for the record-breaking attempt. Recently, Bouchard and his crew took the new bike to the Massachusetts Institute of Technology, where they tested it in a wind tunnel. They are also planning to test it at Gateway International Raceway in St. Louis.
Battle Mountain has been the site of many record-breaking performances by professional, collegiate and amateur riders. The records are sanctioned by the International Human-Powered Vehicle Racing Association.
“Our forecasted performance is looking extremely optimistic,” Bouchard says, “and we are confident that we will break the current record.”
Note: This story has been adapted from a news release issued by University of Missouri-Rolla.

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Thursday, August 30, 2007

NASA Study Will Help Stop Tiny Stowaways To Mars


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Science Daily — NASA clean rooms, where scientists and engineers assemble spacecraft, have joined hot springs, ice caves, and deep mines as unlikely places where scientists have discovered ultra-hardy organisms collectively known as ‘extremophiles’. Some species of bacteria uncovered in a recent NASA study have never been detected anywhere else.
According to Dr. Kasthuri Venkateswaran, who led the study conducted at NASA’s Jet Propulsion Laboratory in Pasadena, California, “These findings will advance the search for life on Mars and other worlds both by sparking improved cleaning and sterilization methods and by preventing false-positive results in future experiments to detect extraterrestrial life.”
NASA builds its spacecraft in rooms designed to minimize contamination by airborne particles because dust and its microbial passengers can foul instruments and invalidate experiments. If scientists someday find microbes on Mars, they will want to be sure they aren’t just hitchhikers from Earth.
Clean rooms used in the space program already undergo extensive cleaning and air filtering procedures, and the detection technology employed in this study will help NASA to develop and monitor improvements. Still, it is extremely difficult to eliminate all dust particles and microbes without damaging the electronic instruments the process is intended to protect.
Identifying and archiving clean-room microbes serves as an effective backup to the cleaning and sterilization efforts. Armed with a list of microbes that could possibly stow away on its spacecraft, NASA can disregard them if they turn up in future Martian samples.
As reported in FEMS Microbiology Ecology, a journal of the Federation of European Microbiological Societies, Venkateswaran’s team used a technology known as ribosomal RNA gene-sequence analysis to detect bacteria in clean rooms at Kennedy Space Center, Johnson Space Center, and the Jet Propulsion Laboratory. This was the first time that this technology was applied to NASA clean rooms.
They found that both the total number of bacteria and the diversity of bacterial species were much higher than previously detected. This has implications not only for NASA and other space agencies, but also for hospital operating rooms and industries such as semiconductor manufacturing, where cleanliness and sterility are critical.
Clean rooms are considered extreme environments for microbes because water and nutrients are in extremely short supply. Nevertheless, some bacteria are able to survive on what little moisture the low-humidity air provides and on trace elements in the wall paint, residue of cleaning solvents, and in the spacecraft materials, themselves.
Reference: The article referred to is Molecular Bacterial Community Analysis of Clean Rooms Where Spacecraft Assembled by Christine Moissl, Shariff Osman, Myron T. La Duc, Anne Dekas, Eoin Brodie, Tadd DeSantis and Kasthuri Venkateswaran
FEMS Microbiology Ecology, 61 (3), 509-521, doi: 10.1111/j.1574-6941.2007.00360.x
Note: This story has been adapted from a news release issued by Blackwell Publishing.

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Wednesday, August 29, 2007

Making Cars Smarter Than You


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Science Daily — Cars already automatically lock doors when they sense motion and turn on warning lights if they detect potential engine problems.
But they are about to get smarter.
The augmented cognition research team at Sandia National Laboratories is designing cars capable of analyzing human behavior.
The car of the future they are developing may, for example, deduce from your driving that you’re become tired, or during critical situations, tell your cell phone to hold an incoming call so you won’t be distracted.
The project started about five years ago with funding by the Defense Advanced Research Projects Agency (DARPA). Four years ago Sandia partnered with a major commercial automobile manufacturer, and three years ago did actual experiments on European roadways.
“We utilized data that already existed on the car’s computer to collect a wide range of physical data such as brake pedal force, acceleration, steering wheel angle, and turn signaling,” says Kevin Dixon, principal investigator. “And specialized sensors including a pressure sensitive chair and an ultrasonic six-degree-of freedom head tracking system measured driver posture.”
Five drivers were fitted with caps connected to electroencephalogram (EEG) (brainwave) electrodes to gauge electrical activity of the brain as they performed driving functions.
The researchers collected several hours of data in unstructured driving conditions that were imputed into Sandia software, referred to as “classifiers,” that categorized driving behavior. These classifiers could detect certain driving situations such as approaching a slow-moving vehicle or changing lanes in preparation to pass another vehicle.
The system detects the difficulty and stress of the task the driver is attempting. It then tries to modify the tasks and/or environment to lower the stress and improved specified performance parameters.
Similar experiments were conducted for off-road driving where conditions were much less structured than typical roadways.
“The beauty of this is that we aren’t doing anything new or different to the car,” Dixon says. “All the software that can make the determination of ‘dangerous’ or ‘safe’ driving situations would all be placed in the computer that already exists in the car. It’s almost like there is another human in the car.”
More recently, the researchers conducted experiments at Camp Pendleton with Marine Corps personnel driving a modified military vehicle. Once again the driver and a passenger sitting in the passenger’s seat were fitted with EEGs. The software classifier determined how difficult the driving situation was and who the best person of the two was to perform a task. For example, during a difficult driving maneuver, it might be best for the passenger to receive radio transmissions in order to not distract the driver
“Every year tens of thousands of people die in automobile crashes, many caused by driver distraction,” Dixon says. “If our algorithms can identify dangerous situations before they happen and alert drivers to them, we will help save lives.”
Sandia is a National Nuclear Security Administration (NNSA) laboratory.
Note: This story has been adapted from a news release issued by Sandia National Laboratories.

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Hydrogen Generating Technology Closer Than Ever


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Science Daily — Researchers at Purdue University have further developed a technology that could represent a pollution-free energy source for a range of potential applications, from golf carts to submarines and cars to emergency portable generators.
The technology produces hydrogen by adding water to an alloy of aluminum and gallium. When water is added to the alloy, the aluminum splits water by attracting oxygen, liberating hydrogen in the process. The Purdue researchers are developing a method to create particles of the alloy that could be placed in a tank to react with water and produce hydrogen on demand.
The gallium is a critical component because it hinders the formation of an aluminum oxide skin normally created on aluminum's surface after bonding with oxygen, a process called oxidation. This skin usually acts as a barrier and prevents oxygen from reacting with aluminum. Reducing the skin's protective properties allows the reaction to continue until all of the aluminum is used to generate hydrogen, said Jerry Woodall, a distinguished professor of electrical and computer engineering at Purdue who invented the process.
Since the technology was first announced in May, researchers have developed an improved form of the alloy that contains a higher concentration of aluminum.
Recent findings are detailed in the first research paper about the work, which will be presented on Sept. 7 during the 2nd Energy Nanotechnology International Conference in Santa Clara, Calif. The paper was written by Woodall, Charles Allen and Jeffrey Ziebarth, both doctoral students in Purdue's School of Electrical and Computer Engineering.
Because the technology could be used to generate hydrogen on demand, the method makes it unnecessary to store or transport hydrogen - two major obstacles in creating a hydrogen economy, Woodall said.
The gallium component is inert, which means it can be recovered and reused.
"This is especially important because of the currently much higher cost of gallium compared with aluminum," Woodall said. "Because gallium can be recovered, this makes the process economically viable and more attractive for large-scale use. Also, since the gallium can be of low purity, the cost of impure gallium is ultimately expected to be many times lower than the high-purity gallium used in the electronics industry."
As the alloy reacts with water, the aluminum turns into aluminum oxide, also called alumina, which can be recycled back into aluminum. The recycled aluminum would be less expensive than mining the metal, making the technology more competitive with other forms of energy production, Woodall said.
In recent research, the engineers rapidly cooled the molten alloy to make particles that were 28 percent aluminum by weight and 72 percent gallium by weight. The result was a "metastable solid alloy" that also readily reacted with water to form hydrogen, alumina and heat, Woodall said.
Following up on that work, the researchers discovered that slowly cooling the molten alloy produced particles that contain 80 percent aluminum and 20 percent gallium.
"Particles made with this 80-20 alloy have good stability in dry air and react rapidly with water to form hydrogen," Woodall said. "This alloy is under intense investigation, and, in our opinion, it can be developed into a commercially viable material for splitting water."
The technology has numerous potential applications. Because the method makes it possible to use hydrogen instead of gasoline to run internal combustion engines, it could be used for cars and trucks. Combusting hydrogen in an engine or using hydrogen to drive a fuel cell produces only water as waste.
"It's a simple matter to convert ordinary internal combustion engines to run on hydrogen. All you have to do is replace the gasoline fuel injector with a hydrogen injector," Woodall said.
The U.S. Department of Energy has set a goal of developing alternative fuels that possess a "hydrogen mass density" of 6 percent by the year 2010 and 9 percent by 2015. The percent mass density of hydrogen is the mass of hydrogen contained in the fuel divided by the total mass of the fuel multiplied by 100. Assuming 50 percent of the water produced as waste is recovered and cycled back into the reaction, the new 80-20 alloy has a hydrogen mass density greater than 6 percent, which meets the DOE's 2010 goal.
Aluminum is refined from the raw mineral bauxite, which also contains gallium. Producing aluminum from bauxite results in waste gallium.
"This technology is feasible for commercial use," Woodall said. "The waste alumina can be recycled back into aluminum, and low-cost gallium is available as a waste product from companies that produce aluminum from the raw mineral bauxite. Enough aluminum exists in the United States to produce 100 trillion kilowatt hours of energy. That's enough energy to meet all the U.S. electric needs for 35 years. If impure gallium can be made for less than $10 a pound and used in an onboard system, there are enough known gallium reserves to run 1 billion cars."
The researchers note in the paper that for the technology to be used to operate cars and trucks, a large-scale recycling program would be required to turn the alumina back into aluminum and to recover the gallium.
"In the meantime, there are other promising potential markets, including lawn mowers and personal motor vehicles such as golf carts and wheelchairs," Woodall said. "The golf cart of the future, three or four years from now, will have an aluminum-gallium alloy. You will add water to generate hydrogen either for an internal combustion engine or to operate a fuel cell that recharges a battery. The battery will then power an electric motor to drive the golf cart."
Another application that is rapidly being developed is for emergency portable generators that will use hydrogen to run a small internal combustion engine. The generators are likely to be on the market within a year, Woodall said.
The technology also could make it possible to introduce a non-polluting way to idle diesel trucks. Truck drivers idle their engines to keep power flowing to appliances and the heating and air conditioning systems while they are making deliveries or parked, but such idling causes air pollution, which has prompted several states to restrict the practice.
The new hydrogen technology could solve the truck-idling dilemma.
"What we are proposing is that the truck would run on either hydrogen or diesel fuel," Woodall said. "While you are on the road you are using the diesel, but while the truck is idling, it's running on hydrogen."
The new hydrogen technology also would be well-suited for submarines because it does not emit toxic fumes and could be used in confined spaces without harming crew members, Woodall said.
"You could replace nuclear submarines with this technology," he said.
Other types of boats, including pleasure craft, also could be equipped with such a technology.
"One reason maritime applications are especially appealing is that you don't have to haul water," Woodall said.
The Purdue researchers had thought that making the process competitive with conventional energy sources would require that the alumina be recycled back into aluminum using a dedicated infrastructure, such as a nuclear power plant or wind generators. However, the researchers now know that recycling the alumina would cost far less than they originally estimated, using standard processing already available.
"Since standard industrial technology could be used to recycle our nearly pure alumina back to aluminum at 20 cents per pound, this technology would be competitive with gasoline," Woodall said. "Using aluminum, it would cost $70 at wholesale prices to take a 350-mile trip with a mid-size car equipped with a standard internal combustion engine. That compares with $66 for gasoline at $3.30 per gallon. If we used a 50 percent efficient fuel cell, taking the same trip using aluminum would cost $28."
The Purdue Research Foundation holds title to the primary patent, which has been filed with the U.S. Patent and Trademark Office and is pending. An Indiana startup company, AlGalCo LLC., has received a license for the exclusive right to commercialize the process.
In 1967, while working as a researcher at IBM, Woodall discovered that liquid alloys of aluminum and gallium spontaneously produce hydrogen if mixed with water. The research, which focused on developing new semiconductors for computers and electronics, led to advances in optical-fiber communications and light-emitting diodes, making them practical for everything from DVD players to television remote controls and new types of lighting displays. That work also led to development of advanced transistors for cell phones and components in solar cells powering space modules like those used on the Mars rover, earning Woodall the 2001 National Medal of Technology from President George W. Bush.
Also while at IBM, Woodall and research engineer Jerome Cuomo were issued a U.S. patent in 1982 for a "solid state, renewable energy supply." The patent described their discovery that when aluminum is dissolved in liquid gallium just above room temperature, the liquid alloy readily reacts with water to form hydrogen, alumina and heat.
Future research will include work to further perfect the solid alloy and develop systems for the controlled delivery of hydrogen.
The 2nd Energy Nanotechnology International Conference is sponsored by the American Society of Mechanical Engineers and ASME Nanotechnology Institute.
Note: This story has been adapted from a news release issued by Purdue University.

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Tuesday, August 28, 2007

Near-Infrared LIDAR Helps Pilots

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Science Daily — Airline pilots will have more advance warning of potentially hazardous atmospheric conditions ¡V such as icing ¡V using a new near-infrared Light Detection and Ranging (LIDAR) system developed by scientists at RL Associates in Chester, Pa. The system, now in a prototype testing phase, will also provide better images in foggy, rainy or extremely hazy conditions, making it easier for pilots to take off and land in those conditions, thereby potentially reducing flight delays.
Right now, other experimental systems use visible green light to detect the different types of particles in the atmosphere. Most commercial planes, however, don't have this kind of system, and flights are grounded rather than risk a foggy landing or misidentifying clouds of icy particles. The RL Associates LIDAR system, which could be quickly commercially deployed, is slated for testing in approximately 18 months.
LIDAR exploits the same basic principle as radar, using light waves instead of radio waves. Lasers use light at wavelengths much smaller than radio waves, so they are much better at detecting very small objects. LIDAR already is frequently used in atmospheric physics ¡V but not on commercial planes ¡V to measure the densities of various particles in the middle and upper atmospheres. According to Mary Ludwig of RL Associates, the system uses a laser light beam that is polarized, or has its electric field pointing in a specific direction. The system beams the polarized infrared light out, and then records the amount of polarization that returns to the sensors. Rain and fog return a less polarized signal, and metal and people return a more polarized signal. The data is then processed to form an image of the ground, or could be translated into verbal commands if needed.
The system can better detect different types of particles in the atmosphere, such as ice, supercooled liquid or just regular water vapor. It can also identify the difference between water vapor and other kinds of substances, such as metal or the human body. Ludwig says the RL Associates system is the first of its kind to use near-infrared. The system also employs a "range-gated detector" that is only turned on for very short periods of time when the return signal is expected. This leads to a vastly improved signal-to-noise ratio, resulting in better images, particularly in obscuring conditions such as fog or haze.
Article: FThG4, "Near-Infrared LIDAR System for Hazard Detection and Mitigation Onboard Aircraft"
Note: This story has been adapted from a news release issued by Optical Society of America.

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Wednesday, August 22, 2007

Pellets Of Power Designed To Deliver Hydrogen For Tomorrow's Vehicles


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Science Daily — Hydrogen may prove to be the fuel of the future in powering the efficient, eco-friendly fuel cell vehicles of tomorrow. Developing a method to safely store, dispense and easily "refuel" the vehicle's storage material with hydrogen has baffled researchers for years. However, a new and attractive storage medium being developed by Pacific Northwest National Laboratory scientists may provide the "power of pellets" to fuel future transportation needs.
The Department of Energy's Chemical Hydrogen Storage Center of Excellence is investigating a hydrogen storage medium that holds promise in meeting long-term targets for transportation use. As part of the center, PNNL scientists are using solid ammonia borane, or AB, compressed into small pellets to serve as a hydrogen storage material. Each milliliter of AB weighs about three-quarters of a gram and harbors up to 1.8 liters of hydrogen.
Researchers expect that a fuel system using small AB pellets will occupy less space and be lighter in weight than systems using pressurized hydrogen gas, thus enabling fuel cell vehicles to have room, range and performance comparable to today's automobiles.
"With this new understanding and our improved methods in working with ammonia borane," said PNNL scientist Dave Heldebrant, "we're making positive strides in developing a viable storage medium to provide reliable, environmentally friendly hydrogen power generation for future transportation needs."
A small pellet of solid ammonia borane (240 mg), as shown, is capable of storing relatively large quantities of hydrogen (0.5 liter) in a very small volume.
PNNL scientists are learning to manipulate the release of hydrogen from AB at predictable rates. By varying temperature and manipulating AB feed rates to a reactor, researchers envision controlling the production of hydrogen and thus fuel cell power, much like a gas pedal regulates fuel to a car's combustion engine. "Once hydrogen from the storage material is depleted, the AB pellets must be safely and efficiently regenerated by way of chemical processing," said PNNL scientist Don Camaioni. "This 'refueling' method requires chemically digesting or breaking down the solid spent fuel into chemicals that can be recycled back to AB with hydrogen."
Don Camaioni and Dave Heldebrant presented this research at the 234th American Chemical Society National Meeting in Boston, Mass. on August 21.
Note: This story has been adapted from a news release issued by DOE/Pacific Northwest National Laboratory.

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Friday, August 17, 2007

Spark-free, Fuel-efficient Engines On The Way


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Science Daily — In an advance that could help curb global demand for oil, MIT researchers have demonstrated how ordinary spark-ignition automobile engines can, under certain driving conditions, move into a spark-free operating mode that is more fuel-efficient and just as clean.The mode-switching capability could appear in production models within a few years, improving fuel economy by several miles per gallon in millions of new cars each year.
Over time, that change could cut oil demand in the United States alone by a million barrels a day. Currently, the U.S. consumes more than 20 million barrels of oil a day.The MIT team presented their latest results on July 23 at the Japan Society of Automotive Engineers (JSAE)/Society of Automotive Engineers (SAE) 2007 International Fuel and Lubricants Meeting.Many researchers are studying a new way of operating an internal combustion engine known as "homogeneous charge compression ignition" (HCCI). Switching a spark-ignition (SI) engine to HCCI mode pushes up its fuel efficiency.In an HCCI engine, fuel and air are mixed together and injected into the cylinder. The piston compresses the mixture until spontaneous combustion occurs. The engine thus combines fuel-and-air premixing (as in an SI engine) with spontaneous ignition (as in a diesel engine). The result is the HCCI's distinctive feature: combustion occurs simultaneously at many locations throughout the combustion chamber.That behavior has advantages. In both SI and diesel engines, the fuel must burn hot to ensure that the flame spreads rapidly through the combustion chamber before a new "charge" enters. In an HCCI engine, there is no need for a quickly spreading flame because combustion occurs throughout the combustion chamber. As a result, combustion temperatures can be lower, so emissions of nitrogen pollutants are negligible. The fuel is spread in low concentrations throughout the cylinder, so the soot emissions from fuel-rich regions in diesels are not present. Perhaps most important, the HCCI engine is not locked into having just enough air to burn the available fuel, as is the SI engine. When the fuel coming into an SI engine is reduced to cut power, the incoming air must also be constrained--a major source of wasted energy. However, it is difficult to control exactly when ignition occurs in an HCCI engine. And if it does not begin when the piston is positioned for the power stroke, the engine will not run right."It's like when you push a kid on a swing," said Professor William H. Green, Jr., of the Department of Chemical Engineering. "You have to push when the swing is all the way back and about to go. If you push at the wrong time, the kid will twist around and not go anywhere. The same thing happens to your engine."According to Green, ignition timing in an HCCI engine depends on two factors: the temperature of the mixture and the detailed chemistry of the fuel. Both are hard to predict and control. So while the HCCI engine performs well under controlled conditions in the laboratory, it is difficult to predict at this time what will happen in the real world.Green, along with Professor Wai K. Cheng of the Department of Mechanical Engineering, and colleagues in MIT's Sloan Automotive Laboratory and MIT's Laboratory for Energy and the Environment have been working to find the answer.A large part of their research has utilized an engine modified to run in either HCCI or SI operating mode. For the past two years, Morgan Andreae (MIT PhD 2006) and graduate student John Angelos of chemical engineering have been studying the engine's behavior as the inlet temperature and type of fuel are changed. Not surprisingly, the range of conditions suitable for HCCI operation is far smaller than the range for SI mode. Variations in temperature had a noticeable but not overwhelming effect on when the HCCI mode worked. Fuel composition had a greater impact, but it was not as much of a showstopper as the researchers expected. Using the results of their engine tests as a guide, the researchers developed an inexpensive technique that should enable a single engine to run in SI mode but switch to HCCI mode whenever possible. A simple temperature sensor determines whether the upcoming cycle should be in SI or HCCI mode (assuming a constant fuel).To estimate potential fuel savings from the mode-switching scheme, Andreae determined when an SI engine would switch into HCCI mode under simulated urban driving conditions. Over the course of the simulated trip, HCCI mode operates about 40 percent of the time.The researchers estimate that the increase in fuel efficiency would be a few miles per gallon. "That may not seem like an impressive improvement," said Green. "But if all the cars in the US today improved that much, it might be worth a million barrels of oil per day--and that's a lot."This research was supported by Ford Motor Company and the Ford-MIT Alliance, with additional support from BP.
Note: This story has been adapted from a news release issued by Massachusetts Institute of Technology.

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Drive-by-wire And Human Behavior Systems Key To New Urban Challenge Vehicle


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Science Daily — Virginia Tech's entry in DARPA's Urban Challenge is moving forward to the qualifying rounds, thanks in part to a custom-designed drive-by-wire control system and unique navigation software that makes the vehicle's driving decisions almost human."VictorTango," a team of Virginia Tech engineering and geography students, is among 36 semi-finalists selected by DARPA (Defense Advanced Research Projects Agency) to vie for the $2 million Urban Challenge prize. Qualifying rounds begin Oct. 26 at the former George Air Force Base in Victorville, Calif., and the final event will take place Nov. 3.
Urban Challenge teams are attempting to develop vehicles that can maneuver a 60-mile course of simulated military supply missions in less than six hours -- with no human intervention allowed past the starting line. The vehicles will have to obey California traffic laws, merge into moving traffic, navigate traffic circles, negotiate intersections, and avoid a variety of obstacles.VictorTango has converted two Escape hybrids donated by Ford Motor Co. into autonomous vehicles by outfitting them with a "drive-by-wire" system, a powerful computer system, laser scanners, cameras, and a GPS (global positioning system), said Patrick Currier, a mechanical engineering (ME) graduate student. The students dubbed the vehicles "Odin" after the chief god in Norse mythology."The drive-by-wire system allows the computers to control the throttle, brake, steering, and shifting and to drive the vehicle," Currier said. "This system was custom developed by the team and is unique in that it is completely hidden from view, enabling Odin to retain full passenger capabilities." TORC Technologies LLC, a company in Virginia Tech's Corporate Research Center founded by alumni of the university's robotics program, has worked with VictorTango to develop the software for the vehicle's computer system. VictorTango and TORC developed Odin's sophisticated navigational software, which is modeled on human behavior. "To successfully navigate in an urban environment, Odin processes all of the sensor information, classifies the situation, and then chooses a behavior, such as passing another vehicle, staying in the lane, or parking," Currier explained. This "human-like" system makes Odin capable of choosing the best course out of millions of possible courses, he said.The team has outfitted Odin with four computers that perform specialized sensor processing and hardware interface tasks and two powerful servers that provide the primary computing power. Three laser scanners mounted on the vehicle's bumpers can scan a combined 360-degree field of view 12.5 times per second to detect obstacles. "These scanners are capable of detecting and tracking cars at a distance of up to 100 meters and are Odin's primary method of detecting other vehicles," Currier said.Four more laser scanners are mounted on Odin's roof rack -- two to detect small obstacles such as curbs and potholes and two to check the vehicle's blind spots when it changes lanes or merges into traffic.Two cameras mounted on the roof rack serve two purposes -- they enable Odin to sense its location and identify its proper position in the traffic lane, and can also positively determine if an obstacle detected by the scanners is another vehicle.Odin's GPS has been coupled with an inertial measurement unit and wheel speed sensors to measure movement in all directions. "This system provides Odin with accurate position, even if the GPS signal is temporarily lost," Currier said."Odin is now capable of driving on a marked road, following moving traffic, passing stopped vehicles, handling four-way intersections, and performing three-point turns," Currier said. The vehicle is being fine-tuned so that it can merge with moving traffic, pass moving vehicles, and park. Currier is one of 10 graduate students on the Virginia Tech team, which also has included as many as 50 undergraduates. The students are guided by four faculty advisers, three of them from Virginia Tech -- professor Alfred Wicks and assistant professor Dennis Hong of the College of Engineering's ME department, and geography department chair Bill Carstensen of the College of Natural Resources. The team's founding adviser, Charles Reinholtz, a former Virginia Tech Alumni Distinguished Professor of ME and engineering education and now the chair of ME at Embry-Riddle Aeronautical University in Florida, continues to work with VictorTango. In October 2006 VictorTango was one of only 11 "track A" teams chosen to receive $1 million contracts to develop autonomous vehicles capable of conducting simulated military supply missions in an urban setting. In all, 89 teams from universities and industry entered the competition in 2006. In addition to the $1 million from DARPA and the two Escapes from Ford, the Virginia Tech team received a $100,000 grant from Caterpillar and additional sponsorship from National Instruments and several other corporations. VictorTango qualified for the semi-finals during a site visit DARPA judges made to Virginia Tech earlier this year. The team's vehicle successfully demonstrated its fully autonomous capabilities, driving a road course and interacting with human-driven vehicles.DARPA is sponsoring the Urban Challenge as a more sophisticated follow-up to the two Grand Challenge competitions, which were held in 2004 and 2005 in the Mojave Desert. Virginia Tech competed in both of those contests, and the university's two entries placed eighth and ninth in 2005. "The Urban Challenge will be far more difficult to navigate than the open desert in the Grand Challenge," Currier said. "In the Grand Challenge, the vehicles followed a GPS 'bread crumb' trail and the obstacles they maneuvered around were static. In the Urban Challenge, vehicles must obey the rules of the road and avoid moving traffic."
Note: This story has been adapted from a news release issued by Virginia Tech.

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Full-time Sensors Can Detect Bridge Defects


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Science Daily — Networks of small, permanently mounted sensors could soon check continuously for the formation of structural defects in I-beams and other critical structural supports of bridges and highway overpasses, giving structural engineers a better chance of heading off catastrophic failures.A Sandia National Laboratories team is developing and evaluating a family of such sensors for use on a variety of safety-critical structures.
Full-time monitoring sensors already have been tested and proven by Sandia for use on aircraft structures.Over time, the stresses on a bridge caused by traffic, weather, and construction can result in the formation of tiny cracks in the steel and concrete structures of bridges. Exposure to wind, rain, and other elements can cause corrosion that can become a structural concern as well. Like nerve endings in a human body, permanently mounted, or in-situ sensors offer levels of vigilance and sensitivity to problems that periodic checkups cannot, says Dennis Roach, who leads the Sandia team.Structural health monitoring (SHM) techniques, as they are called, are gaining acceptance in the commercial aviation sector as a reliable and inexpensive way to alert safety engineers to the first stages of defect formation and give them the earliest possible warning that maintenance is needed. With sensors continually checking for the first signs of wear and tear, engineers can detect cracks sooner, do the right maintenance at the right time, and possibly prevent massive failures, he says.Where flaws formSandia’s SHM work is an extension of its decades of research in non-destructive inspection (NDI) technologies currently used in manual inspections of commercial aircraft — to scan for small cracks in the airframe, for example. The SHM sensors being developed or evaluated at Sandia can find fatigue damage, hidden cracks, erosion, impact damage, and corrosion, among other defects commonly encountered in bridges.The Sandia team already has developed or evaluated several types of inexpensive, reliable sensors that could potentially be mounted on important infrastructure, typically where flaws are expected to form. “If I usually get fatigue damage in a particular area, that’s where I am going to install a sensor,” Roach says.One promising SHM sensor, a Comparative Vacuum Monitoring (CVM) sensor, is a thin, self-adhesive rubber patch, ranging from dime- to credit-card-sized, that detects cracks in the underlying material. The rubber is laser-etched with rows of tiny, interconnected channels or galleries, to which an air pressure is applied. Any propagating crack under the sensor breaches the galleries and the resulting change in pressure is monitored.The CVM sensors — manufactured by Structural Monitoring Systems, Inc. (SMS) — are inexpensive, reliable, durable, and easy to apply, says Roach. More important, they provide equal or better sensitivity than is achievable with conventional inspection methods and can be placed in difficult to access locations, he says.Some other sensors being considered include flexible eddy current arrays, piezoelectric transducers that can interrogate materials over long distances, embedded fiber optics, and conducting paint whose resistance changes when cracks form underneath.Smart structures possible“When we set out to do NDI, in the back of our minds we knew that eventually we wanted to create smart structures that ‘phone home’ when repairs are needed or when the remaining fatigue life drops below acceptable levels,” Roach says. “This is a huge step in the evolution of NDI.”“These sensors have been tested and shown to detect defects and fatigue in metal structures where safety is of utmost concern,” says Roger Hartman, manager of Sandia’s Infrastructure Assurance and NDI Department. By combining networks of sensors of various types with other advanced materials work Sandia has done, such as using composite materials to repair damage to a highway bridge or watching for the first signs of fatigue using computerized prognostics and health management algorithms, “you begin to evolve a system approach to making important infrastructure elements safer and more reliable,” Hartman says. Ultimately, a structural engineer might plug a laptop or diagnostic station into a central port on a bridge to download structural health data. Eventually “smart structures” fitted with many sensors and augmented with PHM algorithms could self-diagnose and signal engineers that repairs are needed or that they will be needed in a defined time downstream.Sandia already is investigating applying SHM to a variety of structures. In addition to bridges and aircraft, SHM techniques could be used to monitor the structural well-being of spacecraft, weapons, rail cars, oil recovery equipment, pipelines, buildings, armored vehicles, ships, wind turbines, nuclear power plants, and fuel tanks in hydrogen vehicles, Roach says. “There is widespread recognition that SHM’s time has come, an opinion you would not have heard from many people a few years ago,” he says.Sandia is a National Nuclear Security Administration laboratory.
Note: This story has been adapted from a news release issued by Sandia National Laboratories.

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