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Grant Awarded for Study of Metallic Material Behavior Under Complex Strain
There are many unanswered questions surrounding the processing of metallic materials relevant for industrial production, such as deformation mechanisms that are crucial in pressing car parts from sheet metal. Conducted by Helena Van Swygenhoven, materials researcher at the Paul Scherrer Institute and professor at the Swiss Federal Institute of Technology in Lausanne (EPFL), the project MULTIAX will study the behavior of metal if it is stretched in different directions and the strain paths change. Van Swygenhoven has received an advanced grant of EUR 2.5 million from the European Research Council (ERC), which supports particularly outstanding projects.
One standout feature of the project is that the behavior is to be studied on three different length scales—from the smallest, where the atomic structure will be observed, to the largest, where entire metal parts are to be examined. “Only by studying the processes separately on different scales can you end up with a complete picture of what goes on in the material,” stresses Van Swygenhoven. “One particular challenge will be to develop a tiny device that can be used specifically to subject small samples to the right strain and enable us to study the processes on a miniscule scale.”
For more information: Paul Scherrer Institut, 5232 Villigen PSI, Switzerland; tel: +41 56 310 21 11; fax: +41 56 310 21 99; web: www.psi.ch.
Plastic Pad Clogs Fukushima Water Cleaning System
Tokyo Electric Power Company (TEPCO) says that the reactors of the crippled Fukushima nuclear plant are stable but need cooling water daily, and has poured thousands of tonnes of water onto them to keep them cool. At the plant, there are three Advanced Liquid Processing Systems (ALPS) designed to remove radioactive material from contaminated water and expected to play a crucial role in treating huge amounts of accumulating toxic water. The utility started trial operations of two of the three systems in March 2013 but halted them in June after corrosion in one was found to be causing water leakage. The third system was activated at the end of September but was stopped later the same day when it was found to not be properly flushing fluid used to remove radioactive particles. Workers found that a plastic pad, which fixed a ladder in the system, had worked loose and gotten stuck in a drain, probably causing the defect.
According to The Japan Times, TEPCO said in November that all three systems were simultaneously in test operations for the first time.
Researchers Work to Identify Weak Water Mains
In collaboration with Sydney Water, UTS researchers are analyzing data collected from pipe inspection tools, including electromagnetic and acoustic sensors, in a 1 km (0.6 mile) stretch of water pipe at Strathfield in Sydney’s Inner West. Monash University is providing an analysis of internal and external factors and stresses affecting the pipe network and the different material types and locations within the system. The University of Newcastle is analyzing the deterioration rates of the pipes within the network, focusing on why and how corrosion and leaching occur. Sydney Water has provided over $5 m toward the project, as well as access to a buried, 1 km, 600 mm (2 ft) diameter test pipe at Strathfield. “We’re using that pipe to gather data and to understand whether our models are working,” said Jaime Valls Miro, an Associate Professor at the UTS Centre for Autonomous Systems and a member of the research team. “This is a five-year project. We’re only two years into it but we feel we are on the right track.”
For more information: Advanced Condition Assessment and Pipe Failure Prediction Project, Department of Civil Engineering, Monash University, Victoria 3800, Australia; tel: +61 3 9905 4984; e-mail: firstname.lastname@example.org; web: www.criticalpipes.com.
Solving Corrosion Problem of Ethanol May Help Speed Biofuel to Market
To meet a goal set by the U.S. Environmental Protection Agency’s Renewable Fuels Standard to use 36 billion gallons per year of biofuels—mostly ethanol—the nation must expand its infrastructure for transporting and storing ethanol. Currently, ethanol is transported via trucks, trains, and barges. For the large volumes required in the future, transportation by pipeline is considered to be the most efficient method. The integrity and safety of pipelines and storage tanks is crucial, because ethanol is both flammable and, at certain concentrations, can cause adverse environmental impacts. “One of the most important concerns with regard to the integrity of pipelines and tanks is the propensity of ethanol at concentrations above 20 vol% in gasoline to cause cracking of steel,” explains Narasi Sridhar, vice president, director of the materials program at Det Norske Veritas.
The Pipeline Research Council International, a consortium of pipeline companies, and the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration funded intense research from 2005 through 2012 to find the cause of cracking of steel in ethanol. “We found that dissolved oxygen in ethanol causes cracking and if oxygen can be removed, cracking can be prevented. This and other engineering measures can form the basis for safe transport of ethanol,” says Sridhar. The fundamental mechanism of how oxygen causes cracking of steel is described in a paper by Liu et al., published in Corrosion journal. This paper is significant because it was extremely difficult to tease apart the fundamental processes occurring in ethanol due to its low electrical conductivity. The practical implication of this paper is that it is now possible to prevent stress-corrosion cracking without resorting to completely removing oxygen from ethanol, which is expensive to do. Sacrificial metals, for example, can be used to prevent cracking. Inhibitors can also be used to prevent cracking by reforming the protective film on steel faster.
For more information: The paper, “Effect of Oxygen on Ethanol SCC Susceptibility, Part 2: Dissolution-Based Cracking Mechanism,” written by Liu Cao, G.S. Frankel, and N. Sridhar, appears in NACE International’s journal, Corrosion, Vol 69 (No. 9), Sept 2013, p 851–862. It is accessible at http://dx.doi.org/10.5006/0895.
Mimicking Nuclear Reactor Damage is Goal of Grant
The researchers will determine how well damage from ion beams in the laboratory mirrors the actual damage that reactor components sustain during decades of service. Today, researchers do not have an efficient way to mimic the radiation damage that current reactor components have sustained or the high damage expected in advanced reactor designs. It would take current test reactors 10 to 20 years to simulate those effects. But ion beams can reach a similar radiation dose in just a few days. “The benefit is a huge reduction in time and cost that will enable much faster development of materials for nuclear reactors,” Was said. But is that damage the same? The collaboration is counting on a new “triple beam” facility at U-M to provide answers.
For more information: University of Michigan, Materials Science and Engineering, tel: 734/763-4970; fax: 734/763-4788; web: www.mse.engin.umich.edu/people/gsw.
Sensor Could Prolong Lifespan of High-Temperature Engines
A temperature sensor developed by researchers at the University of Cambridge could improve the efficiency, control, and safety of high-temperature engines. The sensor has been shown to reduce drift by 80% at temperatures of 1200 °C (2190 °F), and by 90% at 1300 °C (2370 °F), potentially doubling the lifespan of engine components. “A more stable temperature sensor provides several advantages—a better estimation of temperature can increase the lifetime of engine components and decrease maintenance costs to manufacturers, without any reduction in safety,” said Michele Scervini, a postdoctoral researcher in the Department of Materials Science and Metallurgy, who developed the new thermocouple.
For more information: Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, U.K.; tel: 01223 334300 (+44 1223 334300 from outside the U.K.); fax: 01223 334567 (+44 1223 334567 from outside the U.K.); web: www.msm.cam.ac.uk. Research results are published in the Journal of Engineering for Gas Turbines and Power at: http://gasturbinespower.asmedigitalcollection.asme.org/article.aspx?articleid=1723418.
Modelling Approach Boosts Accuracy of Pyrotechnic Shock Testing
All flight hardware used in rocket engines and spacecraft must be tested to ensure it can withstand pyrotechnic shocks that occur during launch, stage separations, and throughout the spacecraft mission profile and still function during flight. Historically, the method used to develop apparatus to perform these shock tests has been based on empirical experience gained only from prior testing that may not reflect the precise shock requirements imposed on the new flight hardware. National Technical Systems, Inc. (NTS) has developed an accurate, physics-based computer modeling approach that enables custom design of shock test apparatus and setup needed to perform high-intensity shock tests required on flight hardware for rocket launch vehicles. The modeling approach, developed by the NTS Ordnance Sciences Division is the first of its kind created specifically for aerospace and defense customers in the Space Mission and Space Launch System (SLS) industry.
If the design of the ordnance induced pyrotechnic shock test does not accurately reflect the requirement, the results of the subsequent testing performed are difficult to assess, noted Jon Conner, NTS Director, Engineering Services, whose group created the new computer modeling approach. The actual tests, which involve inducing pyrotechnic shock by actually detonating explosives against the test apparatus to which the flight hardware is mounted, are expensive and time consuming so it is imperative that the test designs be accurate before they are conducted, Conner added. “This is a dramatic paradigm shift for the industry,” Conner said. “For years, this kind of testing was more an art than a science. Typically you would grossly over-test the hardware to insure the minimum shock level was achieved across the entire frequency spectrum, which can work if the hardware tests out positively. But if it fails, you don’t know if it failed because the hardware needs to be redeveloped to insure adequate margin, or if the failure was due to the gross over-test across much of the frequency spectrum. Our modeling approach brings more science to the pyrotechnic shock test design process, which leads to a better testing and more accurate interpretation of the results.”
For more information: National Technical Systems, Inc., 24007 Ventura Blvd., Suite 200, Calabasas, CA 91302; tel: 800/270-2516 or 818/591-0776; fax: 818/591-0899; web: www.nts.com.
Size Limits Expanded for Nondestructive Testing
This giant piece of equipment has a counterpart no bigger than a microwave oven, and with a resolution of 0.02 mm (0.8 mils), it can scan anything from the smallest plastic parts to biological samples. Now that they have developed what is currently the smallest portable CT scanner in the world, Hanke and his team are already working on the next innovation: a device that will be able to push the limits of geometric magnification down to even higher resolutions. The aim is to be able to scan at nanoscale level, that is, at a magnitude of under 100 nm (4 μin.).
For more information: Fraunhofer-Institut für Integrierte Schaltungen IIS (Fraunhofer Institute for Integrated Circuits IIS), Dr.-Mack-Straße 81, 90762 Fürth, Germany; tel: +49 911 58061-7500; web: www.iis.fraunhofer.de/en/bf/xrt.html.
Study Evaluates Use of Cathodic Protection in Permafrost Regions
The permafrost and semi-permafrost environment of Northern Canada is a huge challenge for designing and engineering underground pipelines, and a critical aspect of protecting both the pipeline and this sensitive environment involves the design of an effective corrosion protection system. One of the most common methods to protect buried infrastructure from corrosion is the application of an external coating, and “although great advances have been made within the past 30 years in terms of coatings reliability and longevity, it’s still desirable to implement a back-up plan: cathodic protection,” says Paul Duchesne, manager of media relations for Natural Resources Canada. Cathodic protection involves attaching sacrificial anodes to the coated steel of a pipeline: sacrificial anodes are more electrically active than steel, so corrosive currents exit through the anodes rather than the steel.
Because the implications of partially frozen ground on cathodic protection systems were not entirely clear, Natural Resources Canada researchers have explored and evaluated the use of cathodic protection in permafrost regions. In a paper published in Corrosion journal, they explain how cathodic protection systems function at low temperature and describe the various aspects of cathodic protection application in subzero temperatures. The researchers concluded that the application of cathodic protection systems may provide long-term protection of the infrastructure from corrosion when combined with high-performance coatings—as long as the system is designed and operated to overcome high-electrical-resistance frozen phases. “Ultimately, we hope that our research will contribute to the safe and reliable operation of underground infrastructure such as oil and gas transmission pipelines, production facilities, and storage tanks,” says Duchesne.
For more information: The paper, “Applicability of Cathodic Protection for Underground Infrastructures Operating at Sub-Zero Temperatures,” by S. Papavinasam, T. Pannerselvam, and A. Doiron, appears in NACE International’s journal, Corrosion, Vol 69 (No. 9), Sept 2013, pp 936–945. It is accessible at http://dx.doi.org/10.5006/0881.
Optical Sensors Improve Railway Safety
A string of fiber optic sensors running along a 36 km (22 mile) stretch of high-speed commuter railroad lines connecting Hong Kong to mainland China has taken more than 10 million measurements over the past few years in a demonstration that the system can help safeguard commuter trains and freight cars against accidents. Attuned to the contact between trains and tracks, the sensors can detect potential problems such as excessive vibrations, mechanical defects, or speed and temperature anomalies. The system is wired to warn train operators immediately of such problems so that they can avoid derailments or other accidents, said Hwa-yaw Tam of the Hong Kong Polytechnic University. At least 30 times during the seven-year period, the system detected anomalous vibrations, Tam said. In a few cases, the vibrations turned out to be early warnings of dangerous emerging conditions that could have led to train wrecks. In some cases, vibration due to the use of the wrong type of lubrication oil in axle boxes was detected. The fiber optic sensor system was designed for maintenance purposes and is estimated to save the rail company approximately $250,000 every year in maintenance costs.
The basis for the new sensor system is a technology developed in the 1970 s and 80 s known as a fiber Bragg grating (FBG), a type of sensor that reflects narrow spectra of light whose wavelengths shift due to temperature/strain variation. Coupling FBGs with another device known as mechanical transducers allows pressure, acceleration, and other parameters to be measured. The sensors are embedded in mechanical compartments of a train or along the tracks. If there is a defect, such as a sudden break in the rails or excessive vibrations because the weight of the train is off balance, those changes will alter the reflection spectra of FBGs in a detectable way. The system is advantageous because it relies exclusively on optical detection and communication, so there are no problems with electromagnetic interference from power lines that run parallel to many modern rail lines. The system is now being installed in all commuter train routes in Hong Kong and will soon be rolled out in railways in parts of Singapore and Australia. With regular speeds for some of the trains in China topping out above 300 km per hour (186 mph), the need for effective safety measures is profound, Tam said.
For more information: Department of Electrical Engineering, EE General Office Counter, Room CF620, Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong; tel: 2766-6150, fax: 2330-1544; web: www.ee.polyu.edu.hk/ee/people-hytam.htm. The article “Utilization of Fiber Optic Bragg Grating Sensing Systems for Health Monitoring in Railway Applications” by Tam et al. is available at: www.micronoptics.com/uploads/library/documents/sensing_documents/FBGs_Rail_Monitoring.pdf.
Coating Changes Color in Corrosion Zones
A research team from the University of Aveiro in Portugal is working to create a novel active protective coating that is able to indicate when corrosion processes start under coatings or in different defects. The nanoreactors being introduced in the coating change color in the zones where corrosion processes start. An important feature of these nanoreactors is that the indicating molecules are not released from the mesoporous nanocarriers, thereby preventing spontaneous leaching and ensuring long service time. The team, led by Mikhail Zheludkevich, a senior researcher at the university’s Department of Materials and Ceramics Engineering (CICECO), published their findings in the September 17, 2013 online edition of Nanotechnology.
These coatings were developed in the frame of the large-scale European project MUST (Multi-Level Protective Materials for Vehicles by “Smart” Nanocontainers). In their work, the team encapsulated phenolphthalein—a colorless crystalline solid often used as an acid-base indicator—in mesoporous silica nanocontainers. The main idea was to provide a color change signal as a result of pH change in the vicinity of a nanocontainer with consecutive diffusion of hydroxide ions into the mesopores reacting with pH indicator within the container. As Zheludkevich points out, the introduction of corrosion sensing functionality to the self-healing coating is an important step that allows detecting the moment when the coating is not able to heal the defects anymore and an external intervention is needed to avoid an extensive corrosive damage. One challenging future direction for this research area is the integration of several functionalities into the protective coatings. The objective would be to develop coatings that not only integrate several self-healing mechanisms at the same time but also provide additional self-monitoring tasks with optional antibacterial or antifouling functionalities.
National Labs and Air Force Partner to Improve Aircraft Component Design
Traditionally, engineers approach component design in a manner that homogenizes the physical properties of a structure. Significant achievements have been made in the longevity of a component by optimizing this process. Now, engineers are looking deeper to incorporate the materials substructure into the design process. To address the strategic need for microstructure data, a diverse team of scientists and engineers developed a novel capability to nondestructively map the material substructure and grain level stresses concurrently in three dimensions. The team is comprised of researchers from the Air Force Research Laboratory (AFRL), the Advanced Photon Source at the U.S. Department of Energy’s Argonne National Laboratory, the Department of Energy’s Lawrence Livermore National Laboratory, Carnegie Mellon University, and PulseRay.
Quantify the average elastic strain and stress tensor for each grain using far-field high-energy diffraction microscopy (HEDM)
Map the grain shape and local crystallographic orientation within and between grains using near-field HEDM
Track the formation and spread of voids and cracks using micro-contrast tomography
These one-of-a-kind datasets provide insight into deformation and form an essential basis for the development and validation of modeling tools. Currently, the capability has been applied to nickel and titanium alloys.
For more information: Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439; tel: 630/252-2000; web: www.anl.gov.