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Cassini finds Saturn moons are active

Saturn’s moons Tethys and Dione are flinging great streams of particles into space, according to data from the NASA, European Space Agency and Italian Space Agency Cassini mission to Saturn. The discovery suggests the possibility of some sort of geological activity, perhaps even volcanic, on these icy worlds. These results appeared in the journal Nature.

The particles measured by Cassini were traced back to the two moons because of the dramatic movement outward from their orbit of electrically charged gas in the magnetic environment of Saturn. Known as plasma, the gas is composed of negatively charged electrons and positively charged ions, which are atoms with one or more electrons missing. Because they're charged, the electrons and ions can become trapped inside a magnetic field.

Saturn rotates in just 10 hours and 46 minutes. This sweeps the magnetic field and the trapped plasma through space. Just like a child on a fast-spinning merry-go-round, the trapped gas feels a force trying to throw it outward, away from the center of rotation.

Soon after the Cassini spacecraft reached Saturn in June 2004, its instruments revealed that the planet’s hurried rotation squashes the plasma into a disc, and that great fingers of gas are being thrown out into space from the disc’s outer edges. Hotter, more tenuous plasma then rushes in to fill the gaps.

Now, Dr. Jim Burch, vice president of the Space Science and Engineering Division at SwRI, and his colleagues on the Cassini Plasma Spectrometer team have shown that the direction of the ejected electrons points back toward Tethys and Dione. “It establishes Tethys and Dione as important sources of plasma in Saturn’s magnetosphere,” said Burch.

More flybys of Dione and Tethys are scheduled in the future, which will allow the magnetometer team and the other instrument teams a close-up look at the moons. Before that happens, the teams have to go back and search for further signs of activity in the data already collected during the Tethys and Dione flybys of 2005.

In addition, Burch says that, having detected the electrons, they will try to determine the composition of the Tethys and Dione plasma using ion data.

The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Cassini Plasma Spectrometer team is based at SwRI. The magnetometer team is based at Imperial College in London, working with team members from the United States and several European countries.

Contact Burch at (210) 522-2526 or jim.burch@swri.org.

SwRI to publish second hydrogen technology information report

Southwest Research Institute is launching its second information subscription service on the status and future prospects for generating and using hydrogen in alternative liquid automotive transportation fuels.

The new information service report, due out in late 2007, focuses on the potential for large-scale production of liquid automotive fuels and blend components, such as dimethyl ether and ethanol, from North American hydrogen-deficient carbon feed stocks during a transition to a future hydrogen fuel economy.

The report will examine the prospects for such fuels to become available in the United States within the next 20 years. Potential feed stocks consist of coal, heavy fossil hydrocarbons from oil shale and tar sands, and biomatter such as plant lignins.

Fuel production from these feed stocks would require heat and hydrogen that could be generated by new nuclear power plants that may be deployed in the United States. Other potential energy and hydrogen sources, such as new-generation coal gasification facilities, will also be discussed.

An earlier report from the first information service, issued in December 2006, focused on automotive-fuel hydrogen generation using nuclear reactors. “The availability of hydrogen from low-carbon emission processes may play a critical role in the U.S. reducing its dependence on foreign petroleum sources as well as reducing greenhouse gas emissions,” said Joe Redfield, manager of Advanced Vehicle Technology in SwRI's Engine, Emissions and Vehicle Research Division.

The report is a joint effort of SwRI’s Geosciences and Engineering Division, the Chemistry and Chemical Engineering Division, the Fuels and Lubricants Research Division and the Engine, Emissions and Vehicle Research Division. Participation in the subscription service is available for a $50,000 fee.

Contact Joe Fohn, Technology Today® editor, at (210) 522-4630 or jfohn@swri.org. For more information on the Hydrogen Technology Information Service, or to subscribe, see http://www.swri.org/4org/d03/vehsys/hydrogen/default.htm

SwRI expands FOCAS® technologies for automotive exhaust catalyst aging

Southwest Research Institute has expanded its FOCAS® technology to include a FOCAS Hot Gas Test Rig (HGTR®) along with its original gasoline burner-based catalyst aging system.

Catalytic converters became a part of the vehicle exhaust system in the mid-1970s to meet emission regulations mandated by the U.S. Environmental Protection Agency. Since the introduction of the three-way catalyst, engineers and scientists have worked to optimize the performance and durability of these devices to meet increasingly stringent emissions and durability standards. Vehicle manufacturers are required by the EPA to demonstrate that a catalyst system meet the emissions regulations for the useful life of the vehicle on which it is used.

When conducting emission testing of new vehicle models, manufacturers use catalysts that have been operated or “aged” for a period that simulates the vehicle’s useful life. The classic approach to aging uses an engine bench stand to accelerate the aging of the catalyst. FOCAS offers a method of aging the catalyst that is much faster and more precise than an engine-based approach.

FOCAS uses a gasoline-fueled burner with an integrated, computerized control system to age catalytic converters. The flow of exhaust gas from an engine can be simulated under a variety of load conditions, allowing full-sized automotive catalyst systems to be rapidly aged. The system is capable of producing exhaust gas at elevated temperatures for extended periods.

“The FOCAS burner-based catalyst-aging system can produce much higher exhaust temperatures than an engine, allowing catalyst aging time to be significantly reduced, saving automotive manufacturers time and money,” said Cynthia Webb, a principal engineer in SwRI's Engine, Emissions and Vehicle Research Division.

Contact Webb at (210) 522-5873 or cynthia.webb@swri.org.

SwRI’s Simpkins earns Health Physics Society Award

Ali Simpkins, a senior research engineer in SwRI’s Geosciences and Engineering Division, has been selected to receive the 2007 Elda E. Anderson Award from the Health Physics Society.

The HPS is a scientific and professional organization whose members specialize in occupational and environmental radiation safety. The award honors the memory of Elda E. Anderson, a pioneer in the field of health physics and a founding member of HPS. It is given to an HPS member 40 years of age or younger in recognition of excellence in “research or development, discovery or invention, devotion to health physics, and/or significant contributions to the profession of health physics.”

Simpkins was recognized for her continued service to the HPS as well as her contribution to environmental health physics, including the development of tritium-derived intervention levels adopted at the federal level.

Simpkins, who joined the SwRI staff in 2006, is a nuclear engineer with experience in environmental pathway analysis, risk assessment and nuclear safety analysis. Her work at SwRI has concerned research on biosphere characteristics in support of regulatory reviews for the potential high-level radioactive waste repository at Yucca Mountain, Nev., and biosphere dose model development.

Simpkins holds bachelor’s and master’s degrees in nuclear engineering from the University of Missouri-Rolla. She is the author or co-author of more than 50 publications, presentations and technical reports and serves as a technical reviewer for the journals Health Physics, Nuclear Technology and Nuclear Safety.

Simpkins is director for the HPS Strategic Plan Goal 5: Government, Public and Society Relations. She is also a member of the American Nuclear Society, Tau Beta Pi, Alpha Nu Sigma and Blue Key.

SwRI opens Minnesota computational mechanics office

Southwest Research Institute has opened an office in Minnesota to enhance its computational capabilities in evaluating the dynamic response of materials and structures to impact and explosive loading.

The Computational Mechanics office, located in Saint Louis Park, Minn., a suburb of Minneapolis, is headed by Dr. Gordon R. Johnson, an internationally known expert in the field of computational modeling of materials. Johnson has joined the SwRI staff as a program director. Other staff members at the Minnesota office are Principal Engineer Timothy J. Holmquist, Senior Research Engineer Dr. Stephen R. Beissel and Research Engineer Dr. Charles A. Gerlach.

“SwRI has collaborated with Dr. Johnson on materials characterization research since the late 1970s and has worked with him and his colleagues on a number of projects,” said Dr. Charles Anderson, director of SwRI’s Engineering Dynamics Department, which will oversee the Minnesota office.

Contact Anderson at (210) 522-2313 or charles.anderson@swri.org.

New method helps forecast radiation hazards up to an hour in advance

One of the greatest threats to human space exploration is the sudden, unpredictable occurrence of radiation outbursts from the Sun. Researchers have long sought a method for predicting when the hazardous particles from extreme solar events, such as flares, coronal mass ejections and radio bursts, would reach humans or technology in space.

Research by Dr. Arik Posner, a research scientist at Southwest Research Institute, has led to a new method for forecasting the appearance and intensity of solar ion events by measuring relativistic, near-light-speed electrons. Relativistic electrons are highly abundant, easy to detect outside of the magnetosphere and detectable ahead of the more dangerous ions that follow. Extreme solar events create the relativistic electrons, which have characteristics that can be exploited to predict the time and intensity of later-arriving ions, predominantly protons with energies more harmful to humans.

Energetic protons and heavier ions are among the main constituents of solar particle events, and their effects on the human body result in a higher cancer risk for humans in space. Exposure to these hazardous particles can also result in acute radiation syndrome, with symptoms that include vomiting, skin burns or abruption of central nervous system function. An early warning system for the detection of hazardous particles could mitigate the risk of radiation damage to astronauts by forecasting impending levels of radiation exposure.

“This method provides advance warning up to about one hour,” said Posner. “Although it seems relatively short notice, the warning can be decisive in the prevention of acute radiation sickness and will help astronauts reduce their total exposure to radiation.”

The method is being considered by the NASA Johnson Space Center in the design of lunar missions. “A one-hour warning would reduce the odds of being caught in a solar storm outside of a lunar habitat, where astronauts are most vulnerable, by more than 20 percent compared to current methods, and allow science missions to venture to farther distances,” said Dr. Francis Cucinotta, chief scientist for the NASA Space Radiation Program.

The study is based on observations by the Comprehensive Suprathermal and Energetic Particle Analyzer (COSTEP) instrument on the Solar and Heliospheric Observatory. SOHO is a project of international cooperation between NASA and the European Space Agency. Since SOHO launched in 1995, COSTEP has provided a wealth of data covering an entire solar cycle, including the 2001 solar maximum, allowing for meaningful tests of this forecasting method.

Contact Posner at (202) 358-0727 or arik.posner@swri.org.

SwRI benchmarking program evaluates four 2007 model year diesel engines

Southwest Research Institute is evaluating four new engines for the Heavy-Duty Diesel Engine Benchmarking program, focusing on the engine performance and fuel consumption associated with new exhaust emissions control technology. Manufacturers developed this new control technology, which uses the ultra-low-sulfur diesel fuel now available nationwide, to meet 2007 U.S. Environmental Protection Agency emissions regulations.

SwRI is benchmarking a light heavy-duty Cummins ISB diesel engine from a Dodge Ram pickup truck plus three heavy, heavy-duty diesel engines: the Caterpillar C15, Cummins ISX and Volvo D13. Additional engines of interest may be added later in the year. The program already includes data from 10 previously benchmarked heavy-duty diesel engines.

“Diesel engine manufacturers are responding to the new EPA regulations by incorporating new exhaust aftertreatment systems that require ultra-low-sulfur diesel fuel,” said Mike Ross, a program manager in the Engine, Emissions and Vehicle Research Division. “These engines are expected to be quite different from their predecessors that met 2004 EPA regulations. It will be interesting to see how each OEM (original engine manufacturer) has addressed the fuel economy issue.”

Contact Ross at (210) 522-2690 or mross@swri.org.

Published in the Summer 2007 issue of Technology Today®, published by Southwest Research Institute. For more information, contact Joe Fohn.

Summer 2007 Technology Today
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