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April 2009

April 30, 2009

Study Finds UK Power Infrastructure Has Capacity for Significant Rise in Use of EVs and PHEVs

According to the results of simulation studies by a consortium including Ricardo, Jaguar-Land Rover, E.ON and Amberjac Projects, a substantial medium-term rise in the number of electric and plug-in hybrid vehicles would have a much lower impact on the UK national power grid than has previously been estimated.

The research study has been carried out by the consortium as part of the Range Extended Hybrid Electric Vehicle (REHEV) project, which is led by Jaguar-Land Rover and part-funded by the UK’s Technology Strategy Board.

The study marks completion of the first stage of the REHEV project and has focused on a range of vehicle charging scenarios and levels of market penetration in order to predict the likely increase in national energy usage.

Four vehicle fleet charging scenarios were simulated, comprising uncontrolled domestic charging, uncontrolled off-peak domestic charging, ‘smart’ domestic charging and uncontrolled public charging throughout the day—for example, by commuters who recharge their vehicles while at work. Charging was assumed to be single phase AC as this is the most likely near-term solution, but the study also considered fast charging scenarios as for a large number of vehicles the energy demanded over a time period is likely to be the same and distributed evenly.

Assuming a 10% market penetration of plug-in hybrid electric vehicles and pure electric vehicles in the UK vehicle parc (a proportion representing approximately 3 million passenger and light goods vehicles) the study showed a daily peak increase in electricity demand of less than 2% (approximately 1GW) for the scenario of uncontrolled domestic charging—the ‘worst case’ in terms of peak power demand.

Other scenarios are less challenging: off-peak domestic charging, for example, increases electricity consumption throughout the night but has no impact on the peak daily demand. Since it will be a number of years before a 10% level of market penetration is achieved even with the recently announced UK government incentive plans, grid capacity at a national scale should be adequate for this significant electrification of the vehicle fleet.

While the national impact is shown to be manageable, the research team emphasizes that local improvements may nevertheless be necessary—for example, where local network capacity is marginal or where particularly high concentrations of electric or plug-in vehicles occur.

Further work is ongoing to look at the timeline for reduced power station CO2 emissions which is the key enabler for electric and plug-in hybrids to reach true ultra-low carbon status. Future reports of the REHEV project will look at fast charging infrastructure which would offer significant consumer benefits in the use of electric and plug-in hybrids.

The REHEV project consortium is now continuing its work, which will see the development of a modular electric and electric/diesel powertrain, suitable for several different vehicle types. This will initially be tested on a large premium sport utility platform, delivering 120 to 130 g/km and with significant zero emissions potential.

Future passenger and commercial variants could have an all electric range of in excess of 20 miles, meaning that the majority of typical vehicle trips could be completed with zero tailpipe emissions.

April 30, 2009 in Hybrids, Plug-ins, Power Generation | Permalink | Comments (15) | TrackBack

Electric Car Corporation Plc Launches the Citroën C1 ev’ie Electric Vehicle

UK-based Electric Car Corporation Plc (ECC) has officially  launched an all-electric version of the Citroën C1, the C1 ev’ie.

C1evie
The C1 ev’ie. Click to enlarge.

The Citroën C1 ev’ie is assembled in the UK from the donor car. The 4-seater electric car offers a range of 60-70 miles when fully charged and a top speed of around 60 mph. Its Li-ion battery pack can be fully charged in 6-7 hours from a domestic 13 amp socket.

ECC expects to produce around 500 C1 ev’ies over the next 12 months, rising to between 2,000 and 4,000 units in 2010, dependant upon demand and government support.

The C1 ev’ie is priced at £16,850 (US$25,000) and is available directly from ECC. Following the launch, the UK car and van hire company Green Motion announced its intention to feature the vehicle within its fleet line-up.

April 30, 2009 in Brief | Permalink | Comments (1) | TrackBack

Magneti Marelli and Flybrid Systems Collaborate on “Flywheel Capacitor” for KERS

Italian motorsport electronics specialist Magneti Marelli and UK high-speed flywheel specialist Flybrid Systems are collaborating to develop a new energy storage solution for Kinetic Energy Recovery Systems (KERS). The new product is targeted to be a high-power electrical storage system for hybrid racing cars capable of deep depths of discharge with no performance degradation and a long service life.

The new product—named the Flywheel Capacitor—consists of a high-speed carbon fiber flywheel incorporating Flybrid technology connected to a high-speed electric motor generator using technology from Magneti Marelli, all managed by Magneti Marelli’s control electronics.

The device works by applying to the electric motor generator the recovered electrical energy captured from the vehicle during braking events. The energy is stored into the Flywheel Capacitor by speeding up the flywheel. During the acceleration events of the vehicle, the energy stored into the flywheel capacitor is returned to the vehicle by transforming the kinetic energy of the flywheel into electrical energy via the motor generator.

The Flywheel capacitor will not use chemical battery-based energy storage systems.

The first Flywheel Capacitor to be developed will have a specification of 60 kW power and 600 kJ total storage capacity but the specification can be readily adapted to any vehicle requirements. Both partners will draw upon extensive experience with their own KERS products to deliver a working prototype in the next few months.

The electric motor and flywheel will rotate at up to 60,000 RPM and the flywheel will sit inside an evacuated chamber that includes special containment features to ensure complete safety. A small electric pump will occasionally top up the vacuum so that no regular maintenance is required.

State of the art magnetic design of the motor generator and high efficiency electronics are expected to deliver round trip storage efficiencies approaching 80%. The device has a low cooling requirement and contains no flammable materials. The complete flywheel capacitor including the associated electronics is expected to weigh just 20 kg.

This is an exciting new development that will deliver a high end product capable of exploitation in F1 but also suitable for more widespread use in motorsport. As well as offering low running costs the flywheel capacitor is a green alternative to regularly replacing batteries.

—Jon Hilton, Flybrid Systems Managing Partner

The new flywheel capacitor product will be commercially available from both Magneti Marelli and Flybrid Systems. Both companies will continue to develop, manufacture and distribute their own existing KERS products—a battery-based system from Magneti Marelli and a flywheel-based system from Flybrid (earlier post).

April 30, 2009 in Hybrids, Motorsport, Vehicle Systems | Permalink | Comments (12) | TrackBack

Chrysler Files for Bankruptcy; Reaches Agreement with Fiat for New Company; Fiat Percentage Ownership Tied to Fuel-Efficiency Targets

Chrysler LLC has been unable to obtain the necessary concessions from all of its lenders which would have avoided the need for a bankruptcy proceeding. As a result, under the direction of the US Treasury, Chrysler LLC and 24 of its wholly-owned US subsidiaries today filed voluntary petitions under Chapter 11 of the US Bankruptcy Code in US Bankruptcy Court for the Southern District of New York.

Chrysler has also reached an agreement in principle to establish a global strategic alliance with Fiat SpA to form a new company. It would allow Chrysler and Fiat to fully optimize their respective manufacturing footprints and the global supplier base, while providing each with access to additional markets. Fiat powertrains and components would also be produced at Chrysler manufacturing sites.

Chrysler will file a motion under Section 363 of the Bankruptcy Code requesting the swift approval by the Court of the agreement with Fiat and the sale of Chrysler’s principal assets to the new company. The benefit of this type of filing is speed. Chrysler hopes this will allow a leaner new company to emerge in a matter of 30 to 60 days.

Fiat cannot become a majority owner until after all US government loans have been completely repaid. When the transaction is completed, the Voluntary Employee Beneficiary Association (VEBA) will own 55% of the new company and the US and Canadian governments will own proportionate shares of a 10% stake. Fiat will initially hold a 20% ownership stake in Chrysler. Fiat will have the right to increase its ownership stake an additional 15% in three increments as it meets the following criteria:

  • 5% for bringing a 40 mpg vehicle platform to Chrysler to be produced in the US;
  • 5% for providing a fuel-efficient engine family to be produced in the US for use in Chrysler vehicles;
  • 5% for providing Chrysler access to its vast global distribution network to facilitate the export of Chrysler vehicles.

As a part of the restructuring, most manufacturing operations will be temporarily idled effective 4 May 2009. Normal production schedules will resume when the transaction is completed, which is anticipated within 30 to 60 days.

Bob Nardelli, Chairman and CEO of Chrysler since August 2007, also announced to Chrysler LLC’s Board of Management and the US Treasury his plan to leave the company following the emergence of the new company from Chapter 11 and the completion of the alliance with Fiat. He will return to Cerberus Capital Management LP as an advisor.

We want to personally assure everyone that the new company will produce and support quality vehicles under the Jeep, Dodge and Chrysler brands as well as parts under the Mopar brand. Chrysler employees will become employees of the new company. Chrysler dealerships remain open for business serving our customers. All vehicle warranties will be honored without interruption and consumers can continue to purchase our vehicles with complete confidence.

—Bob Nardelli

During the restructuring process, the government will provide sufficient debtor-in-possession (DIP) financing to allow continuation of “business as usual.”

...we are using this structured bankruptcy to rapidly implement tough but necessary changes, including: the agreed upon wage and benefit structure for active and retired employees that is competitive with those of transplant manufacturers; a reduction of debt and interest expense; the disposition of idle assets; a rationalized and more efficient dealer network; and sound agreements with our suppliers.

—Bob Nardelli

Chrysler’s Mexican, Canadian and other international operations are not part of any bankruptcy filing.

As part of the restructuring and with the backing of the US Treasury, Chrysler reached an agreement in principle with GMAC to become the preferred lender for Chrysler dealer and consumer business. GMAC will be able to offer the best long-term finance options for Chrysler dealers and customers with standard rate installment products.

April 30, 2009 in Market Background, Policy, Vehicle Manufacturers | Permalink | Comments (16) | TrackBack

UK Collaboration Develops Plug-in Hybrid Retrofit for Conventional Vehicles

Addzev
Battery pack state of charge vs. distance for the ADDZEV vehicle under all-electric power on the UDDC cycle. Source: Cranfield. Click to enlarge.

A collaboration led by the UK’s Cranfield University has developed a retrofit plug-in hybrid conversion system for a conventional internal combustion engine vehicle. The Affordable Add-on Zero Emissions Vehicle (ADDZEV) technology demonstrates how it may be possible to convert segment of the existing the UK vehicle fleet into plug-in hybrid vehicles using a through-the-road approach. (Earlier post.)

Developed to reduce the carbon emissions of inner-city driving, the ADDZEV system was developed using a standard Vauxhall Combo van. The development team retained the existing conventional front-wheel-drive system of the Combo but added an electric drive, powered via low-cost valve regulated lead-acid (VRLA) batteries, to the rear wheels.

This transformed the van into a hybrid vehicle capable of achieving an all-electric range of more than 20 km (12 miles) on one charge.

The ADDZEV consortium includes:

  • Cranfield University. Project lead, control and vehicle integration;
  • European Advanced Lead Acid Battery Consortium. Project management and battery procurement;
  • Millbrook Proving Ground Ltd. Integration, vehicle packaging and testing;
  • Provector Ltd. Development of battery and drive electronics management systems; and
  • University of Oxford. Electric machine design and manufacture, drive system development and integration.

The ADDZEV project team believes that, due to simulation studies using real-world data from a range of vehicles, the technology could be scaled up for larger vans and even city buses.

The ADDZEV system uses twin liquid-cooled motors with a maximum power of 100 kW and peak torque of 350 N·m for maximum gradeability, mounted in a discrete sub-frame under the rear floor of the vehicle. Electric only drive has been limited to propel the vehicle at a speeds up to 60 km/h (37 mph).

For out-of-town driving or higher speed operation, the existing front-wheel-drive diesel power unit provides conventional operation. It can also be configured to switch manually between modes, enabling selection of ultra low emission operation in a low emission zone or city center.

The approximately 4.8 kWh battery pack is charged through specially-devised control software and power management systems created by Cranfield University and Provector. The operational strategy takes the state of charge in the pack down to 40%. Drivers have two options for charge—either by connecting to the electricity grid or via the internal combustion engine that generates and stores energy when the vehicle is in motion.

This results in a typical operating cost for fuel in a small delivery business that could be reduced by 40% compared to operation on traditional fossil fuels alone. The technology, which can be retro-fitted onto a wide range of vehicles, has performed well in final testing at Millbrook, according to the partners.

Conducted as part of the Low Carbon Research and Development program run by the Energy Savings Trust (EST), the project was jointly-funded by the Department for Transport and the European Advanced Lead Acid Battery Consortium.

Resources

April 30, 2009 in Conversions, Hybrids, Plug-ins | Permalink | Comments (1) | TrackBack

Heard At The Show: Snippets from SAE 2009 World Congress

Where does all of the energy go? In a session on total vehicle energy consumption, several people shared similar pie charts showing the flow of energy within an automobile.

For every kJ of chemical energy in the fuel for a spark ignition internal combustion engine, 73 % is sacrificed to chemical and thermal losses. Braking losses add another 6%. Only 22% remains to power the vehicle. Breaking out the 22%, aerodynamic losses account for 39%, tire resistance is 25%, transmission and drivetrain 20%, accessories 12% and bearings 3%.

Major factors contributing to Li-ion battery aging. Michael Crane, Managing Director, HEV N.A., and Continental Corp. shared their data on lithium-ion battery aging. While the numbers will vary depending upon the lithium-ion sub-chemistry, here’s what they have found:

CategoryContribution to Aging
Storage Temperature 40%
Driving Temperature 20%
State of Charge 20%
Cycling 10%
Other 10%

Crane also mentioned that one-quarter to one-third of the cost of a battery system is the packaging, integration and electronics. The cells make up the remainder.

How did the high fuel prices impact customer behavior in 2008? Paul Taylor, Chief Economist for the National Automotive Dealers Association, had the following observations:

At $4/gallon gas people looked at more economical versions of the same vehicle rather than going down in vehicle size—they continue to buy cars that meet their needs. They may take a 4 cylinder version rather than a 6 cylinder version rather than cram themselves into smaller cars. A $1 change in gas prices can lead to a 4-6% shift in take rates (i.e. the 4 cylinder engine may go from a 20% take rate to a 25% take rate). Customers do not make dramatic changes unless it is traumatic times.

Alexander Edwards, President, Automotive Strategic Vision believes the exodus from full size SUVs was caused by economic caution as much as higher gas prices. “People were concerned about spending $35,000 for an SUV that seats five, they were saying for $21,000 I can get a sedan that seats five. It doesn’t do everything I want it to do emotionally” regarding freedom and esteem but it is the more secure choice.

Cash for Clunkers. There are two bills in the US House of Representatives to give people cash for replacing an old, fuel inefficient vehicle with a new, more efficient, one. Similar programs have been successful in Western Europe. Dr. Taylor of the NADA:

At a time when there is $5,000 on the hood of a car, another $2,000 is going to help. But you won’t see the dramatic changes you see in Germany and Japan because they have their inspection regimes that drive them towards newer cars. In this country a lot of the new cars are purchased by higher income households and a typical modest income household is driving a used car...The typical American that is buying a new car, which costs on average $28,000, likely isn’t driving a car worth only $2,000.

How much does it cost to save weight? As the industry grapples with reducing weight without reducing attributes like size, safety or performance they are going to need to increase the use of lightweight materials. Randall Scheps of Alcoa shared research from The Aluminum Association.

The association expects the amount of aluminum per vehicle to increase from 8.6% to 10.4% by 2020 and in one case study they were able to save between 70 and 75 lbs (32 to 34 kg) of vehicle mass for a cost penalty of $280-$350 ($4-$5/lb).

On a “mine to wheels” level, aluminum reduces greenhouse gases vs. steel. Aluminum takes more energy to produce but this is more than offset by improved vehicle performance. The association estimates a net savings of 22 lbs (10 kg) of CO2 per pound (0.45 kg) of aluminum used.

More detail can be found at autoaluminum.org.

Personal mobility redefined. Honda demonstrated their “Walking Assist Device” at the Congress. The systems are designed to maintain mobility for the elderly and those with weakened leg muscles. The devices were found to increase muscle exertion but decrease heart usage in test subjects. Honda is still interpreting the data but they believe the user’s externally powered legs are acted like a second heart, helping pump blood.

Honda also found that the devices improved the users posture and lengthened their stride and these improvements were maintained even after the user was disconnected from the device.

They also demonstrated a similar device called “Walking Assist Device with Bodyweight Support” which provides a little saddle for the user to sit on. A portion of the user’s bodyweight is transferred directly to the floor via special legs and shoes. Honda believes it will be a help in climbing stairs or industrial operations that require a lot of squatting.

Department of Defense and Fuel Economy. Paul F. Skalny, Director, US Army TARDEC shared the following insights on fuel usage within the Department of Defense (DOD):

  • Every $10/barrel increase in oil prices adds $1.3 billion/year to the DOD’s fuel bill.

  • 70% of the bulk tonnage in a war effort is fuel and that fuel can be very expensive financially and in terms of human casualties.

  • The operations in Kuwait and Iraq use approximately 431 million gallons of fuel per year. It takes more than 9,000 convoys to distribute this fuel and each convoy involves approximately 120 soldiers. These convoys are prime targets for improvised explosive devices. If the US could reduce its fuel consumption by 1%, it would save more than 6,000 soldier-trips/year.

  • Fuel becomes very expensive by the time it reaches the front line, ranging from $20/gallon up to $600/gallon when it is delivered by helicopter in Afghanistan.

Skalny and TARDEC are leveraging synergies between the auto industry, the commercial truck business and the federal government to improve the DOD’s fleet fuel economy without sacrificing soldier safety.

—Bill Cooke

April 30, 2009 in Brief | Permalink | Comments (2) | TrackBack

Concept: AET Reaches Final Development Stage of OX2 Barrel Engine

Ox2
Exploded view of the OX2 Engine. Click to enlarge.

Advanced Engine Technologies Inc. says it has reached the final development stage of its OX2 rotary engine, achieving a performance objective of more than 300 lb-ft (407 N·m) of torque along with 46 hp (34 kW) at an approximate operating speed of 760 rpm.

The OX2 engine was conceived in Australia by inventor Steve Manthey. The engine is an 8-cylinder barrel configuration, using a stationary head and cam plate, and rotating cylinder block and piston plates. Each cylinder fires twice per revolution and two cylinders fire simultaneously, resulting in four times the output per revolution of a conventional four-stroke engine at the same displacement. The engine can be adapted to run any combustible gas or liquid as fuel.

Ox2b
OX2 in a test rig. Click to enlarge.

Advanced Engine Technologies was incorporated in 1996 to commercialize the OX2, with automotive racing pioneer Carroll Shelby on its Board of Directors and involved in the engine development.

With its expected higher power-to-weight ratio, multi-fuel capacity and anticipated low emissions and fuel efficiency, the OX2 is initially targeted at the commercial and industrial generator markets. Additional future applications may include marine, light-duty farm and construction equipment, light aircraft, and the hybrid electric vehicle market. However, the near term focus remains electrical generator applications.

The OX2 engine achieves considerable torque at all stages through its operating range. Consequently, in most engine applications there would be no need for the engine to operate at revs higher than 2,500 rpm. In some instances, this would eliminate the need for a gearbox and would certainly reduce engine wear.

However, in particular applications, if high engine revs were mandated, the OX2 engine could be adapted accordingly, AET says. A problem with higher revs is that the centrifugal force lifting the pistons from the track increases, requiring engineering modifications to keep the pistons on track.

The current OX2 is a 4-stroke, 1.1-liter engine that is 17 inches in diameter with a length of 13 inches and a total weight of 200 pounds (91 kg) in normally aspirated form. The compact engine weighs 75% less than and is half the size of traditional internal combustion engines.

The major parts of the engine are the housing; cylinder block; top piston plate; lower piston plate; cam track; and drive shaft. The moving parts are the cylinder block; top piston plate; and lower piston plate.

The combustion chambers are only slightly longer than the stroke and pistons need only to be thick enough to house the rings. The OX2 contains no piston skirts and the rings are the only contact point with the bore. In effect, at no time do the pistons touch the bore, and nor are they reliant on it for support. This system eliminates loading on the sides of the combustion chambers.

Engineers continue work on the commercialization package of the OX2 engine/generator with the fabrication of its finish enclosure and footprint. In addition, AET engineers have prototyped a version of the OX2 engine/generator operating in a vertical orientation.

This new vertical footprint reduces the surface footprint by 50%, allowing the majority of the OX2 engine/generator mass to occupy vertical airspace, not floor space. The company expects to demonstrate both its vertical and horizontal units in the future.

On the heels of AET’s new vertical platform development will be a new, smaller and more versatile power electronics unit. Upon failure of its previous power electronics unit, an outside electrical engineering firm was hired to write the new specifications. The company is poised to proceed with the production of two new power electronics units for fitment with the OX2 engine/generators.

The power electronics is the last mile of the OX2 engine/generator development. The OX2 engine/generator currently produces over 30 kW of power, however it is raw power. This new unit will condition the raw power and produce useable power for commercial connectivity and use.

—John Luft, Chief Operating Officer of AET

In addition to the exciting engineering progress made on the OX2 engine/generator, the company has initiated efforts to raise additional capital to fund the OX2’s 30 Kw Generator final development stage.

Resources

April 30, 2009 in Concept Engines | Permalink | Comments (13) | TrackBack

Hydrogen Engine Center in Demo Project at Montreal Airport

Hydrogen Engine Center, Inc. (HEC) (earlier post) will participate in a C$11 million (US$9.2 million) hydrogen energy technology demonstration project at Montreal’s Pierre Elliot Trudeau International Airport.

The airport project is focused on testing and demonstrating hydrogen technologies and fueling infrastructures. Numerous hydrogen usages will be tested within the project, including but not limited to, passenger transportation, cargo handling, various power sources as well as hydrogen refueling technologies. A main goal of the project is to demonstrate how hydrogen can be integrated into existing environments safely and effectively.

HEC Canada will be responsible for providing and installing up to 10 hydrogen-fueled 4.9-liter internal combustion engines for installation in existing airport luggage tractors. This is a multi-million dollar agreement for which HEC will provide goods and services valued at C$1,151,898. Participation in the project involves an in-kind contribution from HEC in the amount of C$575,949.

The Government of Canada and the Government of Quebec are major partners in the project along with Air Liquide, which is participating in the project and serving as the projects manager. HEC plans to work directly with Air Liquide on all aspects of the hydrogen-fueled internal combustion engines.

April 30, 2009 in Brief | Permalink | Comments (0) | TrackBack

Ames Laboratory Physicists Demonstrate Unique Mechanism of Iron-Arsenide Superconductors

Physicists at the US Department of Energy’s Ames Laboratory have experimentally demonstrated that the superconductivity mechanism in the recently-discovered iron-arsenide superconductors is unique compared to all other known classes of superconductors.

These findings—combined with iron-arsenide’s potential good ability to carry current due to their low anisotropy—may open a door to exciting possible applications in zero-resistance power transmission.

The research, led by Ames Laboratory physicist Ruslan Prozorov, has shown that electron pairing in iron-arsenides is likely to be very different when compared to other types of known superconductors.

In superconducting materials, electrons form pairs, called Cooper pairs, below a critical temperature and these electron pairs behave identically. The collective flow of Cooper pairs results in the most famous feature of a superconductor and the feature that draws the most interest in terms of energy efficiency: the flow of electrical current without any measurable loss of energy, or true zero resistance.

However, superconductors also have another inherent characteristic that distinguishes them from a perfect metal. Unlike perfect metals, superconductors expel a weak magnetic field from their interiors no matter whether they are cooled in a magnetic field or whether the magnetic field is applied after cooling. In either case, a weak magnetic field penetrates only a narrow region at a superconductor’s surface. The depth of this region is known as the London penetration depth.

The change of the London penetration depth with temperature is directly related to the structure of the so-called superconducting gap, which in turn depends on the microscopic mechanism of how electron pairs are formed. London penetration depth is one of the primary experimentally measurable quantities in superconductor studies.

—Ruslan Prozorov

The variation of the London penetration depth with temperature depends on the superconducting gap structure and is already generally agreed upon in most other known classes of superconductors. In conventional superconductors—he class made up of periodic table elements, including lead and niobium—this dependence is exponential at low temperatures. In the high-temperature cuprate superconductors, the relationship is linear, and in magnesium-diboride superconductors the dependence is exponential, but requires two distinct superconducting gaps to explain the data in a full temperature range.

In contrast, the Ames Laboratory research group, which includes physicists Ruslan Prozorov and Makariy Tanatar, postdoctoral researcher Catalin Martin, and graduate students, Ryan Gordon, Matt Vannette and Hyunsoo Kim, found that iron-arsenide superconductors exhibit a power-law—almost quadratic—temperature variation of penetration depth. The team’s results were published in the 27 March issue of Physical Review Letters and the 24 March issue of Physical Review B: Rapid Communications.

The iron-arsenide superconductors’ unique power-law variation of London penetration depth was observed across several FeAs-based systems. The Ames Lab group studied large single crystals of barium-iron-arsenic in which cobalt was substituted for part of the iron, grown and characterized at Ames Lab by senior physicist Paul Canfield’s research group. They also studied neodymium-iron-arsenic-oxide and lanthanum-iron-arsenic-oxide samples grown and characterized by Canfield’s group.

A unique tunnel diode resonator technique was used to measure the London penetration depths of the iron-arsenic crystals. A tunnel diode resonator precisely measures magnetic responses at very low temperatures, and Ames Laboratory is one of the few research facilities in the world with TDR instrumentation.

Since London penetration depth is tied to electron-pairing behavior, the Ames Lab group’s findings suggest that the iron-arsenides also exhibit electron pairing different from any other known superconductor. In addition, the group found unambiguous evidence that the iron-arsenide superconductors’ full data set can only be explained with two distinct superconducting gaps. Thus, the iron-arsenic superconductors appear to exhibit properties of both high-temperatures cuprates and magnesium diboride.

The iron-arsenides are probably among most complex superconductors we—the superconductor research community—have encountered so far. Altogether, analysis of the data collected on many samples shows that the iron-arsenides do not adhere to the previous superconductivity theories and that something else is happening. Of course, some theoretical models do exist, and we collaborate with leading theorists, including Ames Laboratory’s Jörg Schmalian, who has provided important insight into our observations. The unique qualities of the iron-arsenides cause me to believe that materials where transition temperature is closer to room temperature are possible.

—Ruslan Prozorov

The Ames Laboratory research on iron-arsenide superconductors’ London penetration depth was conducted by the Complex States, Emergent Phenomena, and Superconductivity in Intermetallic and Metal-like Compounds Field Work Proposal group, led by physicist Paul Canfield. The research is funded by the US Department of Energy’s Office of Science.

Resources

  • R. T. Gordon, N. Ni, C. Martin, M. A. Tanatar, M. D. Vannette, H. Kim, G. D. Samolyuk, J. Schmalian, S. Nandi, A. Kreyssig, A. I. Goldman, J. Q. Yan, S. L. Bud'ko, P. C. Canfield, and R. Prozorov (2009) Unconventional London Penetration Depth in Single-Crystal Ba(Fe0.93Co0.07)2As2 Superconductors. Phys. Rev. Lett. 102, 127004 doi: 10.1103/PhysRevLett.102.127004

  • R. T. Gordon, C. Martin, H. Kim, N. Ni, M. A. Tanatar, J. Schmalian, I. I. Mazin, S. L. Bud’ko, P. C. Canfield, and R. Prozorov (2009) London penetration depth in single crystals of Ba(Fe1-xCox)2As2 spanning underdoped to overdoped compositions. Phys. Rev. B 79, 100506(R) doi: 10.1103/PhysRevB.79.100506

April 30, 2009 in Brief | Permalink | Comments (0) | TrackBack

Shipping Association Files Suit Against ARB Emission Regulations

Journal of Commerce. The Pacific Merchant Shipping Association, which represents shipping lines and terminal operators, is challenging California Air Resources Board (ARB) regulations in a lawsuit in Federal court, contending that the federal government preempts states in regulating vessel operations beyond a three-mile limit.

In June 2008, ARB adopted a regulation that requires ocean-going vessels (OGV) within 24 nautical miles of California’s coastline to use lower-sulfur marine distillates in their main and auxiliary engines and auxiliary boilers, rather than the dirtier heavy-fuel oil called bunker fuel. (Earlier post.)

PMSA is seeking a permanent injunction against enforcement of the regulation.

PMSA filed its suit in U.S. District Court in Sacramento, Calif., and seeks to enjoin the California Air Resources Board from enforcing the low-sulfur fuel regulation that is scheduled to take effect on July 1.

...PMSA objects to CARB’s attempt to extend its vessel regulations into federal waters. Also, ocean carriers prefer an international approach to vessel emissions regulations, such as the regulations contained in the MARPOL convention to which the U.S. is a signatory.

In March, the US and Canada submitted a proposal to the International Maritime Organization (IMO) for the designation of an Emission Control area (ECA) around their coastlines in which stringent international emission controls would apply to ocean-going ships. (Earlier post.)

April 30, 2009 in Brief | Permalink | Comments (0) | TrackBack

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