Car Prototype Generates Electricity, And Cash

Source:

http://www.sciencedaily.com/releases/2007/12/071203133532.htm

ScienceDaily (Dec. 9, 2007) — The price of oil nearly reached $100 a barrel recently, but a new University of Delaware prototype vehicle demonstrates how the cost of the black stuff could become a concern of the past.

A team of UD faculty has created a system that enables vehicles to not only run on electricity alone, but also to generate revenue by storing and providing electricity for utilities. The technology--known as V2G, for vehicle-to-grid--lets electricity flow from the car’s battery to power lines and back.
“When I get home, I’ll charge up and then switch into V2G mode,” said Willett Kempton, UD associate professor of marine policy and a V2G pioneer who began developing the technology more than a decade ago and who is now testing the new prototype vehicle. The UD V2G team includes Kempton as well as Ajay Prasad, professor of mechanical engineering; Suresh Advani, George W. Laird Professor of Mechanical Engineering; and Meryl Gardner, associate professor of business administration, along with several students.
When the car is in the V2G setting, the battery’s charge goes up or down depending on the needs of the grid operator, which sometimes must store surplus power and other times requires extra power to respond to surges in usage. The ability of the V2G car’s battery to act like a sponge provides a solution for utilities, which pay millions to generating stations that help balance the grid. Kempton estimates the value for utilities could be up to $4,000 a year for the service, part of which could be paid to drivers.
The technology will work on a large scale, he said, because on average 95 percent of all cars are parked at any given time. One hour a day of car usage is the average in America.
“A car sitting there with a tank of gasoline in it, that’s useless,” he said. “If it’s a battery storing a lot of electricity and a big plug that allows moving power back and forth quickly, then it’s valuable.”
Kempton already has one of those large plugs at his home. He has a 240-volt plug that gives the battery a full charge--or a range up to 150 highway miles--in just two hours. A smaller, standard 110-volt plug works but provides a full charge in about 12 hours. The smaller plug also moves less power for the grid operator when the car is in V2G mode, Kempton explained.
“The bigger the plug, the more power you can move, the more revenue,” he said, explaining that it cost about $600 to have the larger plug installed.
But even though Kempton is supplying power to the grid with the prototype car, he’s not getting paid for it--yet.
PJM, the grid operator for 14 states, including Delaware, is keen on the technology and hosted a demonstration of the V2G car. But PJM requires at least 300 megawatts to purchase power. That means the UD team and its collaborators must get 300 cars up and running.
The prototype car is a stepping-stone to that goal. Kempton is working with UD mechanical engineers Prasad and Advani, who plan to add V2G to the University’s hydrogen fuel cell bus. Next, the team, including the company that created the car, California-based AC Propulsion, will test the prototypes and fix any potential problems they bring to light. Then they’ll begin creating a user interface that will let drivers, for example, tell the car to never go below 50 percent charge while in V2G mode.
Helping him to learn what types of features potential buyers would want on the car and to identify potential buyers are business administration faculty member Gardner and her students. They’ve done a pilot survey of nearly 100 drivers that’s shown there’s a lot of interest in the technology, she said.
“We also want to provide information on how to market the car,” she said, so her team is asking people questions like how much they would be willing to pay for it and how they feel about driving a car that’s better for the environment than a gasoline-powered vehicle.
That last question gets Kempton, who also is involved in College of Marine and Earth Studies research on offshore wind farms, the most excited. He explained that even if the electricity used to charge the car is produced by a coal-fired power plant, the car itself produces no carbon dioxide emissions. If a wind farm fuels the electricity from the power plant, he explained, the car and its power source would be emissions free.
And even though the green aspect of the car is key for Kempton, he knows consumers might have some other, more practical, questions about the vehicle, such as, “What’s it like to drive?”
Zippy yet quiet, being behind its wheel is a thrill, he said. “I hate getting back in my gas car. It feels sluggish.”
V2G prototype specifications
The Car: Manufactured by vehicle technology company AC Propulsion; formerly a Toyota Scion, which was chosen because it is light yet provides plenty of passenger room
Emissions: The car itself produces no carbon dioxide emissions
Acceleration: 0 to 60 miles per hour in 7 seconds
Top Speed: 95 miles per hour
Range: 120 highway, 150 city
Battery Life: 5 years or about 50,000 miles (being tested and verified)
Recharge: 2 hours using 240-volt plug or overnight using 110-volt plug
Maintenance: No oil changes; brakes last three times longer because the car has regenerative braking, a mechanism that slows the car and returns power to the battery
Adapted from materials provided by University of Delaware.

Fausto Intilla

www.oloscience.com

Wireless Sensors To Monitor Bearings In Jet Engines Developed

Source:

http://www.sciencedaily.com/releases/2007/10/071030160933.htm

ScienceDaily (Nov. 5, 2007) — Researchers at Purdue University, working with the U.S. Air Force, have developed tiny wireless sensors resilient enough to survive the harsh conditions inside jet engines to detect when critical bearings are close to failing and prevent breakdowns.

The devices are an example of an emerging technology known as "micro electromechanical systems," or MEMS, which are machines that combine electronic and mechanical components on a microscopic scale.
"The MEMS technology is critical because it needs to be small enough that it doesn't interfere with the performance of the bearing itself," said Farshid Sadeghi, a professor of mechanical engineering. "And the other issue is that it needs to be able to withstand extreme heat."
The engine bearings must function amid temperatures of about 300 degrees Celsius, or 572 degrees Fahrenheit.
The researchers have shown that the new sensors can detect impending temperature-induced bearing failure significantly earlier than conventional sensors.
"This kind of advance warning is critical so that you can shut down the engine before it fails," said Dimitrios Peroulis, an assistant professor of electrical and computer engineering.
Findings will be detailed in a research paper to be presented on Tuesday (Oct. 30) during the IEEE Sensors 2007 conference in Atlanta, sponsored by the Institute of Electrical and Electronics Engineers. The paper was written by electrical and computer engineering graduate student Andrew Kovacs, Peroulis and Sadeghi.
The sensors could be in use in a few years in military aircraft such as fighter jets and helicopters. The technology also has potential applications in commercial products, including aircraft and cars.
"Anything that has an engine could benefit through MEMS sensors by keeping track of vital bearings," Peroulis said. "This is going to be the first time that a MEMS component will be made to work in such a harsh environment. It is high temperature, messy, oil is everywhere, and you have high rotational speeds, which subject hardware to extreme stresses."
The work is an extension of Sadeghi's previous research aimed at developing electronic sensors to measure the temperature inside critical bearings in communications satellites.
"This is a major issue for aerospace applications, including bearings in satellite attitude control wheels to keep the satellites in position," Sadeghi said.
The wheels are supported by two bearings. If mission controllers knew the bearings were going bad on a specific unit, they could turn it off and switch to a backup.
"What happens, however, is that you don't get any indication of a bearing's imminent failure, and all of a sudden the gyro stops, causing the satellite to shoot out of orbit," Sadeghi said. "It can take a lot of effort and fuel to try to bring it back to the proper orbit, and many times these efforts fail."
The Purdue researchers received a grant from the U.S. Air Force in 2006 to extend the work for high-temperature applications in jet engines.
"Current sensor technology can withstand temperatures of up to about 210 degrees Celsius, and the military wants to extend that to about 300 degrees Celsius," Sadeghi said. "At the same time, we will need to further miniaturize the size."
The new MEMS sensors provide early detection of impending failure by directly monitoring the temperature of engine bearings, whereas conventional sensors work indirectly by monitoring the temperature of engine oil, yielding less specific data.
The MEMS devices will not require batteries and will transmit temperature data wirelessly.
"This type of system uses a method we call telemetry because the devices transmit signals without wires, and we power the circuitry remotely, eliminating the need for batteries, which do not perform well in high temperatures," Peroulis said.
Power will be provided using a technique called inductive coupling, which uses coils of wire to generate current.
"The major innovation will be the miniaturization and design of the MEMS device, allowing us to install it without disturbing the bearing itself," Peroulis said.
Data from the onboard devices will not only indicate whether a bearing is about to fail but also how long it is likely to last before it fails, Peroulis said.
The research is based at the Birck Nanotechnology Center in Purdue's Discovery Park and at Sadeghi's mechanical engineering laboratory.
Adapted from materials provided by Purdue University.

Fausto Intilla

www.oloscience.com

Acoustic Sensor Being Developed In New Anechoic Chamber

Source:

http://www.sciencedaily.com/releases/2007/10/071030103916.htm

ScienceDaily (Nov. 4, 2007) — The University of Alabama College of Engineering is developing a new acoustic sensor to be tested in UA’s new hemi-anechoic chamber. This new sensor could one day be used to help locate individuals trapped in collapsed buildings, such as after natural or man-made disasters.

Typically, multiple microphones are used to measure the location of an acoustic source, but this project is aimed at developing a single sensor that performs the same task. Its applications will be useful in aiding the military, homeland security and emergency rescue efforts.
“It’s exciting to work on a project that could dramatically change the effectiveness of emergency response teams,” said Dr. Steve Shepard, associate professor in mechanical engineering. “For instance, if a building collapses, our sensor could locate the noises made by victims trapped under debris and help rescue those victims more quickly. The sensor could also be used for security purposes, such as monitoring the location and motion of vehicles.”
Once a prototype is developed, the sensor will be tested in UA’s new hemi-anechoic chamber, which is one of the largest in the Southeast. The chamber is a room that is isolated from external sounds. The walls and ceiling are covered with a very-thick, foam-like material that eliminates all acoustic reflections. Shepard stated that being in the chamber is, “like standing in a very large quiet field. You can almost hear your own heartbeat.” This isolation allows for detailed acoustic measurements on a wide range of structures.
Visually, the chamber resembles a high-tech recording studio. The chamber walls are covered by 2-foot thick, gray, triangular-shaped foam wedges. The 8-inch thick metal walls are filled with insulation made from recycled denim material. Additionally, the entire chamber and the supporting concrete floor, all 150,000 pounds, float on springs to prevent outside vibrations from interfering with acoustic testing. The entire chamber is located in the AIME Building, which has 18-inch thick exterior concrete walls, another sound barrier.
“This chamber gives UA unique acoustic testing capabilities that most research organizations simply don’t have,” said Shepard. “This is true particularly when it comes to testing large machines, structures, and even automobiles. We can now take acoustic measurements on a machine and not worry about the effects of reflections or outside noise. Our ability to better understand how that machine radiates noise – and develop ways to make it quieter – has been greatly extended.”
Shepard said there are several areas researchers hope to explore, including:
reducing noise through powered systems and soundproofing
health monitoring of machines
heating and air conditioning system components
Gear, bearings, motor and engine noise
Consumer product noise and vibration
Shepard was awarded the $120,000 grant from the National Science Foundation to develop the new sensor. UA’s College of Engineering is partnering with Tuskegee University, where researchers received an additional $100,000 grant for their contribution to this research project. Throughout the project, UA and Tuskegee faculty and students will have an opportunity to use the chamber to evaluate prototypes for the acoustic sensor.
Adapted from materials provided by University of Alabama.

Fausto Intilla

www.oloscience.com

New Wireless Bridge Sensors Powered By Passing Traffic

Source:

http://www.sciencedaily.com/releases/2007/10/071019175317.htm

ScienceDaily (Oct. 22, 2007) — Clarkson University researchers have developed technology that uses the vibrations caused by passing traffic to power wireless bridge monitoring sensors.

Wireless battery-powered sensors that monitor bridges and report changes that may lead to failure are easy to install, but it is unwieldy to provide power for the sensors. Each bridge needs at least several sensors, many installed in hard-to-access locations. Replacing millions of batteries could become a problem, adding to the expense of maintaining the bridges. The Clarkson researchers have found a way around this problem.
"We have completely eliminated the battery from the equation," says Assistant Professor Edward S. Sazonov, who developed the technology along with Professor Pragasen Pillay. "Hermetically sealed wireless sensors powered by bridge vibration can remain on the bridge without need of maintenance for decades, providing continuous monitoring of such parameters as ice conditions, traffic flows and health status."
The two electrical and computer engineering professors, along with graduate students Darrell Curry and Haodong Li, used the New York State Route 11 bridge, a steel girder structure, which runs over the Raquette River in Potsdam, N.Y., as a case study.
Energy was harvested by locating an electromagnetic generator on a girder. The harvester responded to one of the natural vibration frequencies of the bridge. Each time a car or a truck passed over the bridge, even in a different lane from the sensor installation, the whole structure vibrated and excited the mover in the generator, producing electrical energy. Harvested electrical energy powered unique wireless sensors that increased energy output of the harvester and consumed only microwatts of power while performing useful tasks.
Sazonov and Pillay have been invited to present their work at the Transportation Research Board of the National Academies Meeting in Washington, D.C., in January. The board provides support for their research.
They are also working on using the energy harvesting technology to power the various sensors in passenger cars.
Wireless monitoring of bridges and overpasses has gained much attention in the past few years. Bridge collapses happen suddenly and unpredictably, often leading to tragic loss of human life. In 2006, the Federal Highway Administration listed 25.8 percent of the nation\'s 596,842 bridges as either structurally deficient or functionally obsolete. While many of these bridges will remain in service for years, they need monitoring and rehabilitation. Currently, bridge monitoring is performed through periodic visual inspections. In the tragic example of I-35W Mississippi River bridge collapse, the bridge passed a visual inspection a year prior to failure.
Adapted from materials provided by Clarkson University.

Fausto Intilla

www.oloscience.com

Hydrogen Storage Model Speeds Development Of Alternative Fuel Vehicles

Source:

http://www.sciencedaily.com/releases/2007/10/071003100601.htm

Science Daily — Researchers at the UCLA Henry Samueli School of Engineering and Applied Science have developed a model that could help engineers and scientists speed up the development of hydrogen-fueled vehicles by identifying promising hydrogen-storage materials and predicting favored thermodynamic chemical reactions through which hydrogen can be reversibly stored and extracted.
Because of global environmental changes associated with man-made carbon dioxide emissions and the limited resources of fossil fuels, developing alternate and renewable energy sources is important for a sustainable future. Hydrogen is a potential source of clean energy for future use in passenger vehicles powered by cheap and energy-efficient fuel cells, but its widespread adoption has been hindered by the need to store it on-board at very high densities.
A promising solution to this problem involves storing hydrogen within a material in the form of a chemically bound hydride, for example lithium hydride (LiH). Unfortunately, simple binary hydrides, in which hydrogen combines with light elements such as lithium, sodium, magnesium or others, do not adequately satisfy the requirements for on-board storage, as the hydrogen-yielding reaction requires heating the material to impractically high temperatures.
Because of this, researchers have turned to multicomponent hydride mixtures with higher volumetric and gravimetric densities, better operating temperatures and improved reaction rates for practical hydrogen storage. However, this flexibility comes at the price of drastically increased complexity associated with the large number of competing reactions and possible end-products other than hydrogen.
Thus, predicting desirable hydrogen storage with multicomponent mixtures has proved difficult. For example, the recently studied lithium hydride compound Li4BN3H10 was found to have as many as 17 hydrogen-release reactions, of which only three were found to be feasible — and none were in the desired range of temperatures and hydrogen pressures for practical on-board storage in hydrogen-powered vehicles.
The research team used modern quantum mechanical theories and high-powered computers to develop an algorithm that can automatically and systematically pinpoint phases and reactions that have the most favored thermodynamic properties — that is, those that can release hydrogen at ambient temperatures using the waste heat from a proton exchange membrane (PEM) fuel cell. The team tested the method on the well-studied Lithium-Magnesium-Nitrogen-Hydrogen system, predicting all experimentally observed pathways in the system. The researchers say this method can also be applied to other multicomponent hydrogen systems.
The new method, published in Advanced Materials, was developed by Alireza Akbarzadeh, a UCLA postdoctoral researcher in the department of materials science and engineering; Vidvuds Ozolins, UCLA associate professor of materials science and engineering; and Christopher Wolverton, professor of materials science and engineering at Northwestern University in Illinois.
"The development of an algorithm that goes beyond chemical intuition and finds all hydrogen storage reactions 'in silico' is crucial and will help the scientific and engineering community to develop revolutionary new hydrogen-storage materials," Akbarzadeh said. "This is a major achievement in the field, which can boost up the search for the best reversible solid-state hydrogen storage."
"We are steadily approaching the moment when we will be able to theoretically design materials with desired properties, just like a tailor makes a suit to fit the customer's needs," Ozolins said. "This will bring in a qualitatively new era of collaboration between theory and computation, experiment and technology development."
The research was funded by grants from the U.S. Department of Energy.
Note: This story has been adapted from material provided by University of California, Los Angeles.

Fausto Intilla
www.oloscience.com

Nanotubes Can Detect And Repair Cracks In Aircraft Wings, Other Structures

Source:

http://www.sciencedaily.com/releases/2007/09/070927132550.htm

Science Daily — Adding even a small amount of carbon nanotubes can go a long way toward enhancing the strength, integrity, and safety of plastic materials widely used in engineering applications, according to a new study.

Researchers at Rensselaer Polytechnic Institute have developed a simple new technique for identifying and repairing small, potentially dangerous cracks in high-performance aircraft wings and many other structures made from polymer composites.
By infusing a polymer with electrically conductive carbon nanotubes, and then monitoring the structure’s electrical resistance, the researchers were able to pinpoint the location and length of a stress-induced crack in a composite structure. Once a crack is located, engineers can then send a short electrical charge to the area in order to heat up the carbon nanotubes and in turn melt an embedded healing agent that will flow into and seal the crack with a 70 percent recovery in strength.
Real-time detection and repair of fatigue-induced damage will greatly enhance the performance, reliability, and safety of structural components in a variety of engineering systems, according to principal investigator Nikhil A. Koratkar, an associate professor in Rensselaer’s Department of Mechanical, Aerospace and Nuclear Engineering.
Details of the project are outlined in the paper “In situ health monitoring and repair in composites using carbon nanotube additives,” which was published online this week by Applied Physics Letters. Rensselaer graduate students Wei Zhang and Varun Sakalkar were co-authors of the paper. The team has been working on the project for more than 18 months.
The majority of failures in any engineered structure are generally due to fatigue-induced microcracks that spread to dangerous proportions and eventually jeopardize the structure’s integrity, Koratkar said. His research is looking to solve this problem with an elegant solution that allows for real-time diagnostics and no additional or expensive equipment.
Koratkar’s team made a structure from common epoxy, the kind used to make everything from the lightweight frames of fighter jet wings to countless devices and components used in manufacturing and industry, but added enough multi-walled carbon nanotubes to comprise 1 percent of the structure’s total weight. The team mechanically mixed the liquid epoxy to ensure the carbon nanotubes were properly dispersed throughout the structure as it dried in a mold.
The researchers also introduced into the structure a series of wires in the form of a grid, which can be used to measure electrical resistance and also apply control voltages to the structure.
By sending a small amount of electricity through the carbon nanotubes, the research team was able to measure the electrical resistance between any two points on the wire grid. They then created a tiny crack in the structure, and measured the electrical resistance between the two nearest grid points. Because the electrical current now had to travel around the crack to get from one point to another, the electrical resistance – the difficulty electricity faces when moving from one place to the next – increased. The longer the crack grew, the higher the electrical resistance between the two points increased.
Koratkar is confident this method will be just as effective with much larger structures. Since the nanotubes are ubiquitous through the structure, this technique can be used to monitor any portion of the structure by performing simple resistance measurements without the need to mount external sensors or sophisticated electronics.
“The beauty of this method is that the carbon nanotubes are everywhere. The sensors are actually an integral part of the structure, which allows you to monitor any part of the structure,” Koratkar said. “We’ve shown that nanoscale science, if applied creatively, can really make a difference in large-scale engineering and structures.”
Koratkar said the new crack detection method should eventually be more cost effective and more convenient than ultrasonic sensors commonly used today. His sensor system can also be used in real time as a device or component is in use, whereas the sonic sensors are external units that require a great deal of time to scan the entire surface area of a stationary structure.
Plus, Koratkar’s system features a built-in repair kit.
When a crack is detected, Koratkar can increase the voltage going through the carbon nanotubes at a particular point in the grid. This extra voltage creates heat, which in turn melts a commercially available healing agent that was mixed into the epoxy. The melted healing agent flows into the crack and cools down, effectively curing the crack. Koratkar shows that these mended structures are about 70 percent as strong as the original, uncracked structure – strong enough to prevent a complete, or catastrophic, structural failure. This method is an effective way to combat both microcracks, as well as a less-common form of structural damage called delamination.
“What’s novel about this application is that we’re using carbon nanotubes not just to detect the crack, but also to heal the crack,” he said. “We use the nanotubes to create localized heat, which melts the healing agent, and that’s what cures the crack.”
Koratkar said he envisions the new system for detecting cracks to eventually be integrated into the built-in computer system of a fighter jet or large piece of equipment. The system will allow the operator to monitor a structure’s integrity in real time, and any microcracks or delamination will become obvious by provoking a change in electrical resistance at some point in the structure.
The system should help increase the lifetime, safety, and cost effectiveness of polymer structures, which are commonly used in place of metal when weight is a factor, Koratkar said. There is also evidence that carbon nanotubes play a passive role in suppressing the rate at which microcracks grow in polymeric structures, which is the subject of a paper Koratkar expects to publish in the near future.
The research is team is now working to optimize the system, scale it up to larger structures, and develop new information technology to better collect and analyze the electrical resistance data created from the embedded grid and embedded carbon nanotubes.
The ongoing research project is funded in part by the National Science Foundation and the U.S. Army.
Note: This story has been adapted from material provided by Rensselaer Polytechnic Institute.

Fausto Intilla

www.oloscience.com

New Material For Aircraft Wings Could Save Billions

Source:

http://www.sciencedaily.com/releases/2007/09/070926094727.htm

Science Daily — Building aircraft wings with a special aluminium fibre combination makes them nearly immune to metal fatigue. The application of this technology, partly developed at Delft University of Technology, will lead to substantial savings.

The unusual qualities of this special material (called CentrAl, an abbreviation of Central Reinforced Aluminium) can make a significant contribution to the development of truly energy-efficient, 'green' aircraft. Lower fuel consumption and reduction of maintenance costs could lead to worldwide savings as high as $100 billion.
Fatigue is a phenomenon that affects materials after long-term exposure to cyclic loading. As a result of varying loads, fractures eventually occur. The new, high-quality CentrAl aluminium constructions are stronger than the carbon fibre reinforced plastic (CFRP) constructions that have recently been used in aircraft wings such as the Boeing 787. By using CentrAl wing constructions, the weight can be reduced by another 20 per cent compared to CFRP constructions. Furthermore, using CentrAl results in considerably lower manufacturing and maintenance costs.
The CentrAl concept comprises a central layer of fibre metal laminate (FML), sandwiched between one or more thick layers of high-quality aluminium. This creates a robust construction material which is not only exceptionally strong, but also insensitive to fatigue. The CentrAl technique allows for simple repairs to be carried out immediately, as is the case in aluminium constructions, -- but not the case when using CFRP constructions.
This patented new concept is one of the results of an intensive collaboration between the company GTM Advanced Structures, founded in The Hague in 2004 and specialising in new aircraft materials and constructions, the American aluminium company Alcoa, and the Faculty of Aerospace Engineering of Delft University of Technology.
During a conference in Delft (Conference on Damage Tolerance of Aircraft Structures: 25-28 September 2007), GTM and Alcoa have presented the new concept to international experts in the field of metal fatigue and damage sensitivity of aircraft constructions. The US Air Force, Alcoa and GTM will also shed new light on the fact that the new CentrAl materials create possibilities for so-called 'Carefree structures'.
These are aircraft constructions that are less sensitive to damage caused, for example, by fatigue, hail storms, other weather phenomena, trucks that collide with the aircraft and corrosion. Carefree aircraft constructions will be characterised by significantly reduced maintenance costs.
Note: This story has been adapted from a news release issued by Delft University of Technology.

Fausto Intilla

www.oloscience.com

Bridge Strengthening Research

Source:

http://www.sciencedaily.com/releases/2007/09/070914163132.htm

Science Daily — These days, a drive across a bridge is not always a pleasure cruise. Mindful of the war on terrorism, it can often be a cautious experience.

In one scenario, someone sets off a series of bombs to weaken the cables and the key structural connections of a major city bridge, all during rush hour. Not easy to do, but now thinkable. This summer, the possibility of sabotage was quickly examined—then dismissed—when the I35W bridge in Minneapolis tragically collapsed into the Mississippi River.
As authorities monitor and stand guard over bridges, the Homeland Security Science & Technology Directorate is looking to scientists and engineers for the security technologies of tomorrow. What if, for instance, we could one day not only guard bridges but fortify them? Like Superman’s blue suit, what if the cables and connections on bridges could be shielded with protective sleeves or covers, making them nearly impossible for the villains to penetrate?
This is the goal of the Directorate's bridge-strengthening research. Through a partnership with the U.S. Army Corps of Engineers’ Engineer Research and Development Center, the Directorate’s Infrastructure and Geophysical Division is testing current bridge designs and investigating advances in steel and reinforced concrete to explore whether such shields could work.
The first step is to determine which bridges and materials are most vulnerable, says Stanley Woodson, who oversees the project at the Center’s Geotech and Structures Lab. A major focus, he says, are the cables and the support columns—or towers—that are used in the cable-stayed design of bridges. Unlike the cables of a suspension bridge, which are attached from tower to tower, the cables in a cable-stayed bridge are connected directly to accessible points along the horizontal bridge deck.
"In controlled experiments, Woodson’s team has been re-creating the forces holding up these bridges and blowing up samples of their cables using various kinds of explosives," say Dr. Mary Ellen Hynes, director of the research. "They then use sophisticated software to analyze the impact and results."
“We tension the cables just like a real bridge,” Woodson explains. “We want to see just how they’d react in an actual terrorist event.”
The next step will be more complicated, says Woodson: Determining what material would suffice for another layer of protection, and what form it should take. “We’re looking at the practical as well as the innovative,” he says, recognizing the potential for high costs.
By the end of 2008, Woodson and his team will be imitating concrete bridge towers and subjecting them to the same explosive testing.
Note: This story has been adapted from a news release issued by Department of Homeland Security.

Fausto Intilla

www.oloscience.com

Skyray 48 Takes Flight

Source:

http://www.sciencedaily.com/releases/2007/09/070919174711.htm

Science Daily — Calm excitement filled the ground control station. Engineers stared intently at their computer screens as the pilot, sitting next to them, flexed his fingers on the controls. Ground crew tending the aircraft finished putting away their equipment. Preparations for the first flight of the unmanned X-48B Blended Wing Body research aircraft were complete.

Years of research, design, construction, wind tunnel and ground tests coalesced into this one moment of time.
Radios crackled. "Tower, Skyray 48 in position, lakebed runway 23, request clearance for takeoff..."
"Skyray 48 roger, main base winds 220 at 6, report airborne, lakebed 23..."
"Wilco"
"Five, four, three, two, one, brakes..."
Quickly, the manta ray-shaped aircraft rolled down the dry lakebed runway trailing a plume of dust as it picked up speed, its three small jet engines whining.
With an excitement that only comes with an aircraft's first flight, the triangular red, white and blue X-48B leapt into the air, obviously wanting to fly.
"Skyray 48's airborne," Boeing pilot Norm Howell called, matter-of-factly. And with that, years of toil blossomed into the sweet fruit of success on July 20, 2007 at NASA's Dryden Flight Research Center on Edwards AFB, Calif.
One of the latest cutting-edge experimental aircraft, or X-Planes, the X-48B BWB is a collaborative effort of the Boeing Co., NASA's Fundamental Aeronautics Program, and the Air Force Research Laboratory. The 21-foot wingspan, 500-pound, remotely piloted plane is designed to demonstrate the viability of the blended wing shape. And demonstrate it has.
After completion of six flights, the X-48B team began a four-week maintenance and modification period during which removable leading edges with extended slats are being replaced with slatless leading edges in order to mimic a slats-retracted configuration. The change requires a software update to the flight control software. In addition, the team is removing and replacing all of the aircraft's flight control actuators for maintenance purposes.
NASA is interested in the potential benefits of the aircraft - increased volume for carrying capacity, efficient aerodynamics for reduced fuel burn, and, possibly, significant reductions in noise due to propulsion integration options. In these initial flights, the principal focus is to validate prior research on the aerodynamic performance and controllability of the shape, including comparisons of flight test data with the extensive database gathered in the wind tunnels at NASA's Langley Research Center in Virginia.
The Subsonic Fixed-Wing Project, part of NASA's Fundamental Aeronautics Program, has long supported the development of the blended wing body concept. It has participated in numerous collaborations with Boeing, as well as several wind tunnel tests for different speed regimes. The team is focused on researching the low-speed characteristics of the design and expanding its flight envelope beyond the limits of current capabilities.
In addition to hosting the X-48B flight test and research activities, NASA Dryden is providing engineering and technical support -- expertise garnered from years of operating cutting-edge air vehicles. NASA assists with the hardware and software validation and verification process, the integration and testing of the aircraft systems, and the pilot's ground control station. NASA's range group provides critical telemetry and command and control communications during the flight, while the flight operations group provides a T-34 chase aircraft and essential flight scheduling. Photo and video support complete the effort.
The composite-skinned, 8.5 percent scale vehicle can to fly up to 10,000 feet and 120 knots in its low-speed configuration. The aircraft is flown remotely from a ground control station by a pilot using conventional aircraft controls and instrumentation, while looking at a monitor fed by a forward-looking camera on the aircraft.
Up to 25 flights are planned to gather data in these low-speed flight regimes. Then, the X-48B may be used to test the aircraft's low-noise and handling characteristics at transonic speeds.
Two X-48B research vehicles were built by Cranfield Aerospace Ltd., in England, in accordance with Boeing specifications. The vehicle that flew on July 20, known as Ship 2, was also used for ground and taxi testing. Ship 1, a duplicate, was used for the wind tunnel tests. Ship 1 is available for use as a backup during the flight test program.
So far, so good as the Skyray 48 team works through the late summer heat of the Mojave Desert as they continue blazing a trail with this futuristic aircraft design.
Note: This story has been adapted from a news release issued by National Aeronautics And Space Administration.

Fausto Intilla

www.oloscience.com

Safer Car Controls

Source:

http://www.sciencedaily.com/releases/2007/09/070909215312.htm

Science Daily — The number of electronic components in cars is growing rapidly. To ensure that vehicle electronics will work properly in future despite the overabundance of software and its increasing complexity, researchers are remodeling it and making it even safer.

The sight of a shiny new car suggests streamlined high-tech devices. But appearances are deceptive. Under the hood, all is confusion. Around 100 microprocessors control auxiliary functions such as ABS, ESP or the headlight that can shine around corners. Almost as many control units send their commands to fuel injection systems, airbags and other functional modules.
Components from numerous manufacturers are scattered throughout the car body. Vehicle development engineers attempting to unite all the different systems into a working entity face a truly Herculean task, for each control unit carries its own software. Experts expect the volume of software in new cars to continue to increase by as much as 300 percent in the next four years.
The Fraunhofer Institute for Software and Systems Engineering ISST in Berlin has joined the international development initiative AUTOSAR (Automotive Open System Architecture) on behalf of the BMW Group. All the well-known car manufacturers and suppliers are members of the partnership. The goal of AUTOSAR is to pare down the ballast of in-car software and make it easier to handle.
The idea behind it is that vehicle functions will first be defined and linked together independently of their specific platforms. Only at the next stage are these functions to be assigned to the vehicle’s existing control units. After this the infrastructural software, likewise standardized, needs to be “fine-tuned”. However, the actual information processing takes place at a higher level, on the AUTOSAR Virtual Functional Bus. This approach simplifies matters tremendously and reveals a way of structuring the growing confusion of software.
“At long last, AUTOSAR gives software integrators in the automotive industry something that developers in other sectors, in the form of standardized development libraries, have had at their fingertips for decades,” says Markus Hardt, head of the department for reliable technical systems at the ISST. But before AUTOSAR can take to the road in tomorrow’s cars, it has to be tested to ensure it functions in a stable manner.
To enable this, Markus Hardt and his colleagues are developing the “aXBench”, a test platform that simulates the AUTOSAR architecture’s mode of operation and suggests an optimal distribution of functions. The “aXBench” enables the scientists to imitate and evaluate the correct functioning of control units, the swift transmission of data between the middleware and the receiver, and even true-to-life details such as hardware and software response times.
Note: This story has been adapted from a news release issued by Fraunhofer-Gesellschaft.

Fausto Intilla

www.oloscience.com

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

Source:

http://www.sciencedaily.com/releases/2007/08/070829191414.htm

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.

Fausto Intilla

www.oloscience.com

NASA Study Will Help Stop Tiny Stowaways To Mars

Source:

http://www.sciencedaily.com/releases/2007/08/070829102036.htm

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.

Fausto Intilla

www.oloscience.com

Making Cars Smarter Than You

Source:

http://www.sciencedaily.com/releases/2007/08/070823180503.htm

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.

Fausto Intilla

www.oloscience.com

Hydrogen Generating Technology Closer Than Ever

Source:

http://www.sciencedaily.com/releases/2007/08/070827174310.htm

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.

Fausto Intilla

www.oloscience.com

Near-Infrared LIDAR Helps Pilots

Source:

http://www.sciencedaily.com/releases/2007/08/070823120237.htm

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.

Fausto Intilla
www.oloscience.com

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

Source:

http://www.sciencedaily.com/releases/2007/08/070821112346.htm

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.

Fausto Intilla

www.oloscience.com

Spark-free, Fuel-efficient Engines On The Way

Source:

http://www.sciencedaily.com/releases/2007/07/070723175256.htm

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.

Fausto Intilla

www.oloscience.com

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

Source:

http://www.sciencedaily.com/releases/2007/08/070810194840.htm

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.

Fausto Intilla

www.oloscience.com

Full-time Sensors Can Detect Bridge Defects

Source:

http://www.sciencedaily.com/releases/2007/08/070811213550.htm

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.

Fausto Intilla

www.oloscience.com