The first battery-electric transit buses in Northern California were put into service today by the San Joaquin Regional Transit District (RTD). The Proterra EcoRide BE35 buses will operate on a rapid charging system and will have all of the functionality of a conventional transit bus.
The California Energy Commission (CEC) provided $2.56 million from its AB 118 program that enabled the RTD to purchase the electric buses.
By recharging for 10 minutes every two hours, the buses will be able to operate throughout the entire daily operation cycle. AeroVironment is providing the rapid charging technology.
The AeroVironment charging station is fully automated. When the Proterra bus approaches the charge station, the station recognizes the bus, guides the bus into position, and charges the vehicle without driver interaction.
Both fine-particle air pollution and noise pollution may increase a person’s risk of developing cardiovascular disease, according to German researchers who have conducted a large population study, in which both factors were considered simultaneously. The research was presented today at the ATS (American Thoracic Society) 2013 conference in Philadelphia.
Many studies have looked at air pollution, while others have looked at noise pollution. This study looked at both at the same time and found that each form of pollution was independently associated with subclinical atherosclerosis.—Barbara Hoffmann, MD, MPH, study leader
This study is important because it says that both air pollution and noise pollution represent important health problems. In the past, some air pollution studies have been dismissed because critics said it was probably the noise pollution that caused the harm, and vice versa. Now we know that people who live near highways, for instance, are being harmed by air pollution and by noise pollution.—Dr. Philip Harber, University of Arizona, not involved in the research
Using data from the Heinz Nixdorf Recall study, an ongoing population study from three neighboring cities in the Ruhr region of Germany, Dr. Hoffmann and her colleagues assessed the long-term exposure to fine particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) and long-term exposure to traffic noise in 4238 study participants (mean age 60 years, 49.9% male).
The exposure to air pollutants was calculated using the EURopean Air Pollution Disperson, or EURAD, model. Exposure to traffic noise was calculated using European Union models of outdoor traffic noise levels. These levels were quantified as weighted 24-hour mean exposure (Lden) and nighttime exposure (Lnight).
To determine the association of the two variables with cardiovascular risk, the researchers looked at thoracic aortic calcification (TAC), a measure of subclinical atherosclerosis.
TAC was quantified using non-contrast enhanced electron beam computed tomography. Using multiple linear regression, the researchers controlled for other cardiovascular risk factors, including age, gender, education, unemployment, smoking status and history, exposure to second-hand smoke, physical activity, alcohol use and body mass index.
After controlling for these variables, the researchers found that fine-particle air pollution was associated with an increase in TAC burden by 19.9% (95%CI 8.2; 32.8%) per 2.4µg/m3. (As a point of comparison, in the US, the Environmental Protection Agency recently revised the overall limit downward from 15 to 12µg/m3).
The researchers also found that nighttime traffic noise pollution increased TAC burden by 8% (95% CI 0.8; 8.9%) per 5 dB. (An average living room would typically have a noise level of about 40 A-weighted decibels, or dB(A), an expression of the relative loudness of sounds as perceived by the human ear, while busy road traffic would generate about 70-80dB(A)). Mean exposure to traffic noise over 24 hours was not associated with increased TAC.
Among subgroups of participants, the researchers found even stronger associations. The interaction of PM2.5 and TAC was clearer among those younger than 65, participants with prevalent coronary artery disease and those taking statins. In contrast, the effect of Lnight was stronger in participants who were not obese, did not have coronary artery disease and did not take statins.
Although the cross-sectional design of this study limits the causal interpretation of the data, Dr. Hoffmann said, “both exposures seem to be important and both must be considered on a population level, rather than focusing on just one hazard.”
She added that her research group plans to conduct a longitudinal analysis with repeated measures of TAC over time.
Titanium Corporation Inc. has been awarded the final of the three core Canadian patents on its oil sands tailings technology. (Earlier post.) The latest, Canadian Patent Nº 2662346 (Moran et al) is for a novel process that recovers bitumen from froth treatment tailings.
Titanium has also received the final results of independent testing on its recent pilot at CanmetENERGY, further confirming that its technology can recover large quantities of residual bitumen, solvents and minerals from oil sands tailings, with environmental benefits including some reduction in greenhouse gas (GHG) emissions.
Titanium’s pilot achieved recoveries of 82% of residual bitumen from the oil sands tailings stream and 98% of the solvents. The pilot produced a large bulk sample of heavy mineral concentrates for separation processing into samples of zircon, an essential material in the worldwide ceramics industry. The pilot achieved all of its objectives at larger scale processing.
While it takes time to commercialize new technology, we are seeing increasing support from stakeholders for our technology, which would recover up to 7,000 barrels per day of currently wasted bitumen and solvent from individual oil sands operations.—Scott Nelson, Titanium’s President and CEO
During the 10-week pilot, more than 5,000 independent sample analyses were performed by Maxxam Analytics. The Canadian Government Sustainable Development Technology Canada SD Tech Fund contributed $1.4 million of funding to the pilot.
Researchers at the Department of Energy’s Pacific Northwest National Laboratory (PNNL) and Bonneville Power Administration (BPA) have identified two compressed air energy storage methods for the temporary storage of the Northwest’s excess wind power and two eastern Washington locations to put them into practice.
Compressed air energy storage plants could help save the region’s abundant wind power—which is often produced at night when winds are strong and energy demand is low—for when demand is high and power supplies are more strained. These plants can also switch between energy storage and power generation within minutes, providing flexibility to balance the region’s highly variable wind energy generation throughout the day.
All compressed air energy storage plants work under the same basic premise. When power is abundant, it’s drawn from the electric grid and used to power a large air compressor, which pushes pressurized air into an underground geologic storage structure. Later, when power demand is high, the stored air is released back up to the surface, where it is heated and rushes through turbines to generate electricity. Compressed air energy storage plants can re-generate as much as 80% of the electricity they take in.
The world’s two existing compressed air energy storage plants—one in Alabama, the other in Germany—use man-made salt caverns to store excess electricity. The PNNL-BPA study examined a different approach: using natural, porous rock reservoirs that are deep underground to store renewable energy.
Interest in the technology has increased greatly in the past decade as utilities and others seek better ways to integrate renewable energy onto the power grid. About 13%, or nearly 8,600 megawatts, of the Northwest’s power supply comes from of wind. This prompted BPA and PNNL to investigate whether the technology could be used in the Northwest.
To find potential sites, the research team reviewed the Columbia Plateau Province, a thick layer of volcanic basalt rock that covers much of the region. The team looked for underground basalt reservoirs that were at least 1,500 feet deep, 30 feet thick and close to high-voltage transmission lines, among other criteria.
They then examined public data from wells drilled for gas exploration or research at the Hanford Site in southeastern Washington. Well data was plugged into PNNL’s STOMP computer model, which simulates the movement of fluids below ground, to determine how much air the various sites under consideration could reliably hold and return to the surface.
Analysis identified two particularly promising locations in eastern Washington. One location, dubbed the Columbia Hills Site, is just north of Boardman, Ore., on the Washington side of the Columbia River. The second, called the Yakima Minerals Site, is about 10 miles north of Selah, Wash., in an area called the Yakima Canyon.
The research team determined the two sites are suitable for two very different kinds of compressed air energy storage facilities. The Columbia Hills Site could access a nearby natural gas pipeline, making it a good fit for a conventional compressed air energy facility. Such a conventional facility would burn a small amount of natural gas to heat compressed air that’s released from underground storage. The heated air would then generate more than twice the power than a typical natural gas power plant.
The Yakima Minerals Site, however, doesn’t have easy access to natural gas. So the research team devised a different kind of compressed air energy storage facility: one that uses geothermal energy. This hybrid facility would extract geothermal heat from deep underground to power a chiller that would cool the facility's air compressors, making them more efficient. Geothermal energy would also re-heat the air as it returns to the surface.
The study indicates both facilities could provide energy storage during extended periods of time. This could especially help the Northwest during the spring, when sometimes there is more wind and hydroelectric power than the region can absorb. The combination of heavy runoff from melting snow and a large amount of wind, which often blows at night when demand for electricity is low, can spike power production in the region. To keep the regional power grid stable in such a situation, power system managers must reduce power generation or store the excess power supply. Energy storage technologies such as compressed air energy storage can help the region make the most of its excess clean energy production.
Working with the Northwest Power and Conservation Council, BPA will now use the performance and economic data from the study to perform an in-depth analysis of the net benefits compressed air energy storage could bring to the Pacific Northwest. The results could be used by one or more regional utilities to develop a commercial compressed air energy storage demonstration project.
The $790,000 joint feasibility study was funded by BPA’s Technology Innovation Office, PNNL and several project partners: Seattle City Light, Washington State University Tri-Cities, GreenFire Energy, Snohomish County Public Utility District, Dresser-Rand, Puget Sound Energy, Ramgen Power Systems, NW Natural, Magnum Energy and Portland General Electric.
Resources
BP McGrail, JE Cabe, CL Davidson, FS Knudsen, DH Bacon, MD Bearden, MA Chamness, JA Horner, SP Reidel, HT Schaef, FA Spane, PD Thorne, “Techno-economic Performance Evaluation of Compressed Air Energy Storage in the Pacific Northwest,” February 2013
Honda Cars India Limited (HCIL) recently launched the Honda Amaze for the Indian market, marking Honda’s entry into the diesel segment there. India is the first country to launch the Amaze with Honda’s latest i-DTEC diesel engine technology. The gasoline model of the Amaze will be equipped with an i-VTEC engine.
Powered by the 1.5L 4 cylinder DOHC i-DTEC diesel engine, the Amaze is the most fuel efficient car in the country with a certified mileage of 25.8 km/l (61 mpg US, 3.9 l/100 km), as per test data. The 1.5L diesel engine delivers 100 PS (98 hp, 73 kW) @3600 rpm and 200 N·m (149 lb-ft) of torque @1750 rpm.
The 1.5L i-DTEC engine was developed exclusively for India considering Indian driving conditions and is based on the Honda’s latest Earth Dreams Technology. With an all-aluminum cylinder head joined to an open deck engine block, it is the lightest engine in its torque performing class. The use of lightweight crankshaft and a number of friction-reduction technologies help to control friction in a diesel engine to gasoline engine levels.
Honeywell designed and built the wastegate-type turbocharger for the Honda Amaze.
Honda Amaze is being manufactured at HCIL’s facility in Greater Noida, U.P. with localisation level of more than 90%. The body panels, critical engine components for both i-VTEC and i-DTEC engine and Manual Transmission are being manufactured in-house at HCIL’s Tapukara facility and are supplied to Greater Noida plant.
Researchers at MIT have demonstrated two approaches for producing carbon fibers coated in carbon nanotubes without degrading the underlying fiber’s strength. A paper on the work, which could result in carbon-fiber composites that are not only stronger but also more electrically conductive, is published in the journal ACS Applied Materials & Interfaces.
Hierarchical carbon fibers (CFs) sheathed with radial arrays of carbon nanotubes (CNTs) are promising candidates for improving the intra- and interlaminar properties of advanced fiber-reinforced composites (such as graphite/epoxy) and for high-surface-area electrodes for battery and supercapacitor architectures, the authors note.
However, while chemical vapor deposition (CVD) growth of CNTs on CFs can improve the apparent shear strength between fibers and polymer matrices by up to 60%, this has to date been achieved only at the expense of significant reductions in tensile strength (30–50%) and stiffness (10–20%) of the underlying fiber.
We observe that CVD-induced reduction of fiber strength and stiffness is primarily attributable to mechanochemical reorganization of the underlying fiber when heated untensioned above 550 °C in both hydrocarbon-containing and inert atmospheres. We show that tensioning fibers to ≥12% of tensile strength during CVD enables aligned CNT growth while simultaneously preserving fiber strength and stiffness even at growth temperatures >700 °C.
We also show that CNT growth employing CO2/acetylene at 480 °C without tensioning—below the identified critical strength-loss temperature—preserves fiber strength. These results highlight previously unidentified mechanisms underlying synthesis of hierarchical CFs and demonstrate scalable, facile methods for doing so.—Steiner et al.
Applying their discoveries, the researchers coated carbon fibers with nanotubes without causing fiber degradation, making the fibers twice as strong as previous nanotube-coated fibers. The researchers say the techniques can easily be integrated into current fiber-manufacturing processes.
To understand how carbon fibers are manufactured, the group visited carbon-fiber production plants in Japan, Germany and Tennessee. One aspect of the fiber-manufacturing process stood out: During manufacturing, fibers are stretched to near their breaking point as they are heated to high temperatures. In contrast, researchers who have tried to grow nanotubes on carbon fibers in the lab typically do not use tension in their fabrication processes.
Using a small-scale apparatus made of graphite, the researchers strung individual carbon fibers across the device and hung tiny weights on either end of each fiber, pulling them taut. The group then grew carbon nanotubes on the fibers, first covering the fibers with a special set of coatings, and then heating the fibers in a furnace. They then used chemical vapor deposition to grow a fuzzy layer of nanotubes along each fiber.
To get nanotubes to grow, the fiber typically needs to be coated with a metal catalyst such as iron, but researchers have hypothesized that such catalysts might also be the source of fiber degradation. In their experiments, however, they found that the catalyst only contributed to about 15% of the fiber’s degradation.
Instead, the group found, after further experiments, that the majority of fiber degradation was due to a previously unidentified mechanochemical phenomenon arising from a lack of tension when carbon fibers are heated above a certain temperature. They then devised two practical strategies for growing nanotubes on carbon fiber that preserve fiber strength.
First, the team coated the carbon fiber with a layer of alumina ceramic to “disguise” it, enabling the iron catalyst to stick to the fiber without degrading it. The solution, however, came with another challenge: the layer of alumina kept flaking off.
To keep the alumina in place, the team developed a polymer coating called K-PSMA, which has hydrophilic and hydrophobic components. The hydrophobic feature sticks to the carbon fiber, while the hydrophilic component attracts the alumina and the metal catalyst.
The coating allowed the alumina and metal catalyst to stick, without having to add other processes, such as pre-etching the fiber surface. The team placed the coated fibers under tension, and successfully grew nanotubes without damaging the fiber.
For the second strategy, using a recently discovered nanotube-growth process together with K-PSMA, the team demonstrated it is possible to grow nanotubes at a much lower temperature—nearly 300 °C cooler than is typically used—avoiding damage to the underlying fiber.
Milo Shaffer, a professor of materials chemistry at Imperial College, London, says the group’s carbon-fiber techniques may be useful in designing composites for use in electrodes and air filters. A next step toward this goal, he says, is to make sure the fiber’s various layers and coatings stay in place.
The researchers have filed a patent for the two strategies, and envision advanced fiber composites incorporating their techniques for a whole range of applications.
This study provides, for the first time, viable pathways for growing CNTs on carbon fibers suitable for advanced composites applications without compromising in-plane properties. Hierarchical carbon fibers produced through these approaches may also find application as electrodes for batteries, supercapacitors, and structures that double as energy-storing devices.
We note that while unsized fibers such as those used in this study may provide a more ideal surface for the application of functional coatings than sized fibers, current commercial manufacture of carbon fibers relies on sizings for many aspects of processing and handling, and many resin systems leverage carbon fiber sizings for fiber-matrix bonding. This said, the approaches demonstrated in this work could easily be extended to sized fibers by appropriately tailoring the polyelectrolyte and sizing chemistries to allow for noncovalent functionalization of sized carbon fiber surfaces. Alternatively, sized fibers could be de-sized (i.e., the sizing could be removed) prior to CNT growth via solvent treatment or thermal treatment in air or inert atmosphere.
Hierarchical carbon fibers offer numerous processing advantages over sized carbon fibers, however, including the ability to wick resins into the fiber via capillarity-driven wetting as well as greatly enhanced interfacial area for bond formation, suggesting that hierarchical carbon fibers such as those produced in this work may ultimately displace the need for sizings altogether.—Steiner et al.
Resources
Stephen A. Steiner, III, Richard Li, and Brian L. Wardle (2013) Circumventing the Mechanochemical Origins of Strength Loss in the Synthesis of Hierarchical Carbon Fibers. ACS Applied Materials & Interfaces doi: 10.1021/am4006385
US fuel ethanol production capacity was 13.852 billion gallons per year (903,000 barrels per day), as of 1 January 2013, according to the latest annual report released by the US Energy Information Administration (EIA). The report shows a 0.9% increase in the total capacity of operating ethanol plants compared to 1 January 2012 (13.728 billion gallons/year). A total of 193 ethanol plants were operating as of 1 January 2013, compared to 194 plants operating a year earlier.
Most of the existing fuel ethanol capacity (about 91%) is located in the Midwest (PAD District 2). Total nameplate capacity in PADD 2 is 12.6 billion gallons per year (822,000 barrels per day). The number of plants in this report includes plants that were idled or temporarily shut down during 2012.
(PADDs, Petroleum Administration for Defense Districts, were created by the Federal government during World War II to help to organize the allocation of fuels. The districts are now used for data collection.)
The report includes data for the total nameplate production capacity for all operating fuel ethanol production plants as of 1 January 2013. Nameplate production capacity, the measure of capacity tracked by EIA, is the volume of denatured (made unfit for human consumption) fuel ethanol that can be produced during a period of 12 months under normal operating conditions.
The total capacities in the report are listed by region (PAD Districts) in both millions of gallons per year and thousands of barrels per day. The report is updated annually.
In two previous reports on ethanol capacity, EIA included data on maximum sustainable production capacity of ethanol plants. Starting with this third report, EIA decided to publish only nameplate production capacities, and will discontinue collection and publication of maximum sustainable capacity data.
EIA determined that nameplate capacity is a sufficient measure of available ethanol production capacity, and the additional burden on respondents to report a maximum sustainable capacity number is not justified by the value and utility of the information.
The next EIA annual report on ethanol production capacity is expected to be released during the spring of 2014. The 2014 report will include facility-level nameplate production capacity data, which will increase the transparency of the ethanol industry data.
The capacity data are reported to EIA by respondents on the EIA-819 Monthly Oxygenate Report. The EIA-819 is submitted by all operating fuel ethanol and other oxygenate production plants within the United States.
