Engineerblogger
Feb 23, 2012
The condensation of water is crucial to the operation of most of the powerplants that provide our electricity — whether they are fueled by coal, natural gas or nuclear fuel. It is also the key to producing potable water from salty or brackish water. But there are still large gaps in the scientific understanding of exactly how water condenses on the surfaces used to turn steam back into water in a powerplant, or to condense water in an evaporation-based desalination plant.
New research by a team at MIT offers important new insights into how these droplets form, and ways to pattern the collecting surfaces at the nanoscale to encourage droplets to form more rapidly. These insights could enable a new generation of significantly more efficient powerplants and desalination plants, the researchers say.
The new results were published online this month in the journal ACS Nano, a publication of the American Chemical Society, in a paper by MIT mechanical engineering graduate student Nenad Miljkovic, postdoc Ryan Enright and associate professor Evelyn Wang.
Although analysis of condensation mechanisms is an old field, Miljkovic says, it has re-emerged in recent years with the rise of micro- and nanopatterning technologies that shape condensing surfaces to an unprecedented degree. The key property of surfaces that influences droplet-forming behavior is known as “wettability,” which determines whether droplets stand high on a surface like water drops on a hot griddle, or spread out quickly to form a thin film.
It’s a question that’s key to the operation of powerplants, where water is boiled using fossil fuel or the heat of nuclear fission; the resulting steam drives a turbine attached to a dynamo, producing electricity. After exiting the turbine, the steam needs to cool and condense back into liquid water, so it can return to the boiler and begin the process again. (That’s what goes on inside the giant cooling towers seen at powerplants.)
Typically, on a condensing surface, droplets gradually grow larger while adhering to the material through surface tension. Once they get so big that gravity overcomes the surface tension holding them in place, they rain down into a container below. But it turns out there are ways to get them to fall from the surface — and even to “jump” from the surface — at much smaller sizes, long before gravity takes over. That reduces the size of the removed droplets and makes the resulting transfer of heat much more efficient, Miljkovic says.
One mechanism is a surface pattern that encourages adjacent droplets to merge together. As they do so, energy is released, which “causes a recoil from the surface, and droplets will actually jump off,” Miljkovic says. That mechanism has been observed before, he notes, but the new work “adds a new chapter to the story. Few researchers have looked at the growth of the droplets prior to the jumping in detail.”
That’s important because even if the jumping effect allows droplets to leave the surface faster than they would otherwise, if their growth lags, you might actually reduce efficiency. In other words, it’s not just the size of the droplet when it gets released that matters, but also how fast it grows to that size.
“This has not been identified before,” Miljkovic says. And in many cases, the team found, “you think you’re getting enhanced heat transfer, but you’re actually getting worse heat transfer.”
In previous research, “heat transfer has not been explicitly measured,” he says, because it’s difficult to measure and the field of condensation with surface patterning is still fairly young. By incorporating measurements of droplet growth rates and heat transfer into their computer models, the MIT team was able to compare a variety of approaches to the surface patterning and find those that actually provided the most efficient transfer of heat.
One approach has been to create a forest of tiny pillars on the surface: Droplets tend to sit on top of the pillars while only locally wetting the surface rather than wetting the whole surface, minimizing the area of contact and facilitating easier release. But the exact sizes, spacing, width-to-height ratios and nanoscale roughness of the pillars can make a big difference in how well they work, the team found.
“We showed that our surfaces improved heat transfer up to 71 percent [compared to flat, non-wetting surfaces currently used only in high-efficiency condenser systems] if you tailor them properly,” Miljkovic says. With more work to explore variations in surface patterns, it should be possible to improve even further, he says.
The enhanced efficiency could also improve the rate of water production in plants that produce drinking water from seawater, or even in proposed new solar-power systems that rely on maximizing evaporator (solar collector) surface area and minimizing condenser (heat exchanger) surface area to increase the overall efficiency of solar-energy collection. A similar system could improve heat removal in computer chips, which is often based on internal evaporation and recondensation of a heat-transfer liquid through a device called a heat pipe.
Chuan-Hua Chen, an assistant professor of mechanical engineering and materials science at Duke University who was not involved in this work, says, “It is intriguing to see the coexistence of both sphere- and balloon-shaped condensate drops on the same structure. … Very little is known at the scales resolved by the environmental electron microscope used in this paper. Such findings will likely influence future research on anti-dew materials and … condensers.”
The next step in the research, underway now, is to extend the findings from the droplet experiments and computer modeling — and to find even more efficient configurations and ways of manufacturing them rapidly and inexpensively on an industrial scale, Miljkovic says.
This work was supported as part of the MIT S3TEC Center, an Energy Frontier Research Center funded by the U.S. Department of Energy.
Source: MIT News
Thursday, 23 February 2012
SPIDERS microgrid project secures military installations
Engineerblogger
Feb 23, 2012
When the lights go out, most of us find flashlights, dig out board games and wait for the power to come back. But that’s not an option for hospitals and military installations, where lives are on the line. Power outages can have disastrous consequences for such critical organizations, and it’s especially unsettling that they rely on the nation’s aging, fragile and fossil-fuel dependent grid.
A three-phase, $30 million, multi-agency project known as SPIDERS, or the Smart Power Infrastructure Demonstration for Energy Reliability and Security, is focused on lessening those risks by building smarter, more secure and robust microgrids that incorporate renewable energy sources.
Sandia was selected as the lead designer for SPIDERS, the first major project under a Memorandum of Understanding (MOU) signed by the Department of Energy (DOE) and the Department of Defense (DoD) to accelerate joint innovations in clean energy and national energy security. The effort builds on Sandia’s decade of experience with microgrids – localized, closed-circuit grids that both generate and consume power – that can be run connected to or independent of the larger utility grid.
The goal for SPIDERS microgrid technology is to provide secure control of on-base generation.
“If there is a disruption to the commercial utility power grid, a secure microgrid can isolate from the grid and provide backup power to ensure continuity of mission-critical loads. The microgrid can allow time for the commercial utility to restore service and coordinate reconnection when service is stabilized,” said Col. Nancy Grandy, oversight executive of the SPIDERS Joint Capability Technology Demonstration (JCTD). “This capability provides much-needed energy security for our vital military missions.”
SPIDERS is addressing the challenge of tying intermittent clean energy sources such as solar and wind to a grid. “People run single diesel generators all the time to support buildings, but they don’t run interconnected diesels with solar, hydrogen fuel cells and so on, as a significant energy source. It’s not completely unheard of, but it’s a real integration challenge,” said Jason Stamp, Sandia’s lead project engineer for SPIDERS.
Currently, when power is disrupted at a military base, individual buildings switch to backup diesel generators, but that approach has several limitations. Generators might fail to start, and if a building’s backup power system doesn’t start, there is no way to use power from another building’s generator. Most generators are oversized for the load and run at less-than-optimal capacity, and excess fuel is consumed. Furthermore, safety requirements state that all renewable energy sources on base must disconnect when off-site power is lost.
A smart, cybersecure microgrid addresses these issues by allowing renewable energy sources to stay connected and run in coordination with diesel generators, which can all be brought online as needed. Such a system would dramatically help the military increase power reliability, lessen its need for diesel fuel and reduce its “carbon bootprint.”
“The military has indicated it wants to be protected against disruptions, to integrate renewable energy sources and to reduce petroleum demand,” Stamp said. “SPIDERS is focused on accomplishing those tasks, and the end result is having better energy delivery for critical mission support, and that is important for every American.”
SPIDERS uses existing, commercially available technologies for implementation, so the individual technologies are not novel. “What’s novel is the system integration of the various technologies, and demonstrating them in an operational field environment. Microgrid concepts are still fairly new, and that’s where Sandia’s microgrid design expertise is coming into play,” said Sandia researcher Bill Waugaman, SPIDERS operational lead.
It is common practice to connect diesel generators to buildings, but integrating significant amounts of energy from intermittent clean sources such as solar and wind to that system is unique, and it is a challenge that Sandia and SPIDERS are working to address.
Such integration requires data to determine the most efficient and effective way to operate, but that can open system vulnerabilities, so cybersecurity is paramount. SPIDERS addresses that issue by incorporating an unprecedented level of cybersecurity into the system from the outset.
“Any perturbation of information flow by an adversary would possibly cause an interruption to electrical service, which can have significant consequences,” Stamp said. “It’s important that if we build a microgrid system that depends explicitly on greater information flow, that it operate as intended: reliably and securely.”
SPIDERS is funded and managed through the DoD’s JCTD, which joins the efforts of other government organizations and companies to rapidly develop, assess and transition needed capabilities to support DoD missions. With the DOE’s support, the SPIDERS transition plan includes civilian facilities.
“The SPIDERS approach has many applications beyond military uses. Our interest in SPIDERS extends to organizations, like hospitals, that are critical to our nation’s functionality, especially in times of emergency,” said Merrill Smith, DOE program manager.
Sandia’s microgrid expertise spans the past decade, beginning when Sandia designed microgrids for the DOE’s Federal Energy Management Program (FEMP) and the DOE’s Office of Electricity Delivery and Energy Reliability (OE). The DOE initially asked Sandia to develop a conceptual design for a microgrid at Fort Carson in Colorado Springs, Colo., and another for Camp H.M. Smith in Hawaii.
After Sandia conducted a feasibility analysis and modeling and simulation work for the two bases, U.S. Pacific Command (USPACOM) and U.S. Northern Command (USNORTHCOM) asked Sandia to prove the concept through field work under a JCTD. The two commands pulled together a team of national labs and defense organizations, and selected Sandia to lead the development of the initial designs for three separate microgrids, each more complex than the previous.
The Army Construction Engineering Research Laboratory will use the Sandia designs as a basis for developing contracts with potential system integrators, who will construct the actual microgrids. Other partners in the SPIDERS JCTD include National Renewable Energy Laboratory for renewable energy and electrical vehicle expertise, Pacific Northwest National Laboratory for testing and transition, Oak Ridge National Laboratory to assist with control system development and Idaho National Laboratory for cybersecurity.
The first SPIDERS microgrid will be implemented at Joint Base Pearl Harbor Hickam in Honolulu, and will take advantage of several existing generation assets, including a 146-kW photovoltaic solar power system, and up to 50 kW of wind power. The integrator for the project has been selected and the final design and construction process is underway.
The second installation, at Fort Carson, is much larger and more complex and will integrate an existing 2 MW of solar power, several large diesel generators and electric vehicles. Large-scale electrical energy storage will also be implemented to ensure microgrid stability and to reduce the effects of PV variability on the system. Camp H.M. Smith, the most ambitious project, will rely on solar and diesel generators to power the entire base, which will be its own self-sufficient 5 MW microgrid when the national grid is unavailable.
Integration and implementation are scheduled through 2014. The goal is to install the circuit level demonstration at Pearl Hickam and Fort Carson next year, with Camp Smith installed in 2013.
Source: Sandia National Laboratories
Feb 23, 2012
 |
| Bill Waugaman is the SPIDERS operational lead at Sandia National Laboratories. Credit: Randy Montoya |
When the lights go out, most of us find flashlights, dig out board games and wait for the power to come back. But that’s not an option for hospitals and military installations, where lives are on the line. Power outages can have disastrous consequences for such critical organizations, and it’s especially unsettling that they rely on the nation’s aging, fragile and fossil-fuel dependent grid.
A three-phase, $30 million, multi-agency project known as SPIDERS, or the Smart Power Infrastructure Demonstration for Energy Reliability and Security, is focused on lessening those risks by building smarter, more secure and robust microgrids that incorporate renewable energy sources.
Sandia was selected as the lead designer for SPIDERS, the first major project under a Memorandum of Understanding (MOU) signed by the Department of Energy (DOE) and the Department of Defense (DoD) to accelerate joint innovations in clean energy and national energy security. The effort builds on Sandia’s decade of experience with microgrids – localized, closed-circuit grids that both generate and consume power – that can be run connected to or independent of the larger utility grid.
The goal for SPIDERS microgrid technology is to provide secure control of on-base generation.
“If there is a disruption to the commercial utility power grid, a secure microgrid can isolate from the grid and provide backup power to ensure continuity of mission-critical loads. The microgrid can allow time for the commercial utility to restore service and coordinate reconnection when service is stabilized,” said Col. Nancy Grandy, oversight executive of the SPIDERS Joint Capability Technology Demonstration (JCTD). “This capability provides much-needed energy security for our vital military missions.”
SPIDERS is addressing the challenge of tying intermittent clean energy sources such as solar and wind to a grid. “People run single diesel generators all the time to support buildings, but they don’t run interconnected diesels with solar, hydrogen fuel cells and so on, as a significant energy source. It’s not completely unheard of, but it’s a real integration challenge,” said Jason Stamp, Sandia’s lead project engineer for SPIDERS.
Currently, when power is disrupted at a military base, individual buildings switch to backup diesel generators, but that approach has several limitations. Generators might fail to start, and if a building’s backup power system doesn’t start, there is no way to use power from another building’s generator. Most generators are oversized for the load and run at less-than-optimal capacity, and excess fuel is consumed. Furthermore, safety requirements state that all renewable energy sources on base must disconnect when off-site power is lost.
A smart, cybersecure microgrid addresses these issues by allowing renewable energy sources to stay connected and run in coordination with diesel generators, which can all be brought online as needed. Such a system would dramatically help the military increase power reliability, lessen its need for diesel fuel and reduce its “carbon bootprint.”
“The military has indicated it wants to be protected against disruptions, to integrate renewable energy sources and to reduce petroleum demand,” Stamp said. “SPIDERS is focused on accomplishing those tasks, and the end result is having better energy delivery for critical mission support, and that is important for every American.”
SPIDERS uses existing, commercially available technologies for implementation, so the individual technologies are not novel. “What’s novel is the system integration of the various technologies, and demonstrating them in an operational field environment. Microgrid concepts are still fairly new, and that’s where Sandia’s microgrid design expertise is coming into play,” said Sandia researcher Bill Waugaman, SPIDERS operational lead.
It is common practice to connect diesel generators to buildings, but integrating significant amounts of energy from intermittent clean sources such as solar and wind to that system is unique, and it is a challenge that Sandia and SPIDERS are working to address.
Such integration requires data to determine the most efficient and effective way to operate, but that can open system vulnerabilities, so cybersecurity is paramount. SPIDERS addresses that issue by incorporating an unprecedented level of cybersecurity into the system from the outset.
“Any perturbation of information flow by an adversary would possibly cause an interruption to electrical service, which can have significant consequences,” Stamp said. “It’s important that if we build a microgrid system that depends explicitly on greater information flow, that it operate as intended: reliably and securely.”
SPIDERS is funded and managed through the DoD’s JCTD, which joins the efforts of other government organizations and companies to rapidly develop, assess and transition needed capabilities to support DoD missions. With the DOE’s support, the SPIDERS transition plan includes civilian facilities.
“The SPIDERS approach has many applications beyond military uses. Our interest in SPIDERS extends to organizations, like hospitals, that are critical to our nation’s functionality, especially in times of emergency,” said Merrill Smith, DOE program manager.
Sandia’s microgrid expertise spans the past decade, beginning when Sandia designed microgrids for the DOE’s Federal Energy Management Program (FEMP) and the DOE’s Office of Electricity Delivery and Energy Reliability (OE). The DOE initially asked Sandia to develop a conceptual design for a microgrid at Fort Carson in Colorado Springs, Colo., and another for Camp H.M. Smith in Hawaii.
After Sandia conducted a feasibility analysis and modeling and simulation work for the two bases, U.S. Pacific Command (USPACOM) and U.S. Northern Command (USNORTHCOM) asked Sandia to prove the concept through field work under a JCTD. The two commands pulled together a team of national labs and defense organizations, and selected Sandia to lead the development of the initial designs for three separate microgrids, each more complex than the previous.
The Army Construction Engineering Research Laboratory will use the Sandia designs as a basis for developing contracts with potential system integrators, who will construct the actual microgrids. Other partners in the SPIDERS JCTD include National Renewable Energy Laboratory for renewable energy and electrical vehicle expertise, Pacific Northwest National Laboratory for testing and transition, Oak Ridge National Laboratory to assist with control system development and Idaho National Laboratory for cybersecurity.
The first SPIDERS microgrid will be implemented at Joint Base Pearl Harbor Hickam in Honolulu, and will take advantage of several existing generation assets, including a 146-kW photovoltaic solar power system, and up to 50 kW of wind power. The integrator for the project has been selected and the final design and construction process is underway.
The second installation, at Fort Carson, is much larger and more complex and will integrate an existing 2 MW of solar power, several large diesel generators and electric vehicles. Large-scale electrical energy storage will also be implemented to ensure microgrid stability and to reduce the effects of PV variability on the system. Camp H.M. Smith, the most ambitious project, will rely on solar and diesel generators to power the entire base, which will be its own self-sufficient 5 MW microgrid when the national grid is unavailable.
Integration and implementation are scheduled through 2014. The goal is to install the circuit level demonstration at Pearl Hickam and Fort Carson next year, with Camp Smith installed in 2013.
Source: Sandia National Laboratories
An Early Start on Innovation: Corporations inspire the next generation of researchers to embrace science and innovation
R&D Magazine
Feb 23, 2012
In order for technology companies to bring innovative products to market, they need enthusiastic, educated scientists and engineers to drive the process. To inspire the next generation of researchers, some industrial developers are going back to school.
A 2011 Harvard University study found that U.S. students ranked behind 31 other countries in math and science efficiency, and fewer than one in three students are proficient in science after high school.
A recent teleconference held in October by STEM Connects, a curriculum and career development resource from Discovery Education—an educational resource for teachers—reported that 10 to 15% of students in the U.S. enter college as science, technology, engineering, or mathematics (STEM) majors; in China that number is 30 to 40%, paving the way for a scientific and technological advantage for that nation.
"I think people need to realize that a lack of students going into STEM fields not only affects the learning curves in schools, but it also affects our global competitiveness and our ability as a nation to innovate," says Jennifer Harper-Taylor, president of the Siemens Foundation, Iselin, N.J. "If we don’t have a smart workforce, we are not going to have sophisticated R&D happening."
To drive more interest to these fields, industrial companies are helping students understand the importance of science and mathematics, and are promoting STEM education and innovation to the next generation.
From school to scientific discovery
"One of the keys to innovation is engaging the future scientists and engineers of our nation," says Tom Buckmaster, president of Honeywell Hometown Solutions, Morris Township, N.J. "The more students that have an interest in science and math means the possibility of more scientists and engineers our society could have, which will expand our nation’s capacity for innovation."
Agilent Technologies Inc., Santa Clara, Calif., promotes hands-on learning to enhance understanding of basic science concepts. The company has created the Agilent After School program, a hands-on, experimental science program targeted at children from the ages 9 to 13. The program has reached 550,000 students globally; and Agilent has invested around $3.5 million in the program in the past 10 years.
The program features 22 kits or projects that range from simple experiments for elementary school students, to more complex experiments that require advanced critical thinking and measurement skills for high school students. Projects include creating electronic circuit boards and balloon- or solar-powered cars, learning how to clean up oil spills, and solving a crime scene mystery. Held at universities and other local facilities, Agilent employees teach the students the basics about their projects and what they are creating, providing the students with knowledge that they can take back to their classrooms.
"Students really love the hands-on aspect of the projects, and in turn love leaving with what they built," says Terry Lincoln, Agilent Technologies’ global signature programs manager. "They also love the engagement between themselves and the employee running the program and talking about their project, making them want to take their projects outside of the program and into the classroom."
Science hits the road
Morris Township, N.J.-based Honeywell International has partnered with NASA to create FMA Live!, a program that explains Sir Isaac Newton's laws of motion in an exciting and entertaining way. The MTV-style interactive traveling show teaches basic science concepts and engages future engineers and scientists in the seventh to ninth grades.
FMA Live! features high-energy actors, music, videos, and demonstrations to teach Newton's laws of motion and the process of scientific inquiry. During each performance, students, teachers, and school administrators interact with three professional actors on stage in front of a live audience.
The actors use a large Velcro wall to demonstrate inertia when a student jumps off a springboard and is immediately stuck to the wall. Go-carts race across the stage to illustrate action and reaction. Extreme wrestling and a giant soccer ball show how force equals mass multiplied by acceleration. All three laws are shown simultaneously when a participant—usually a teacher or administrator—rides a futuristic hover chair and collides face first with a gigantic cream pie, exciting the students and providing lasting and memorable lessons, says Buckmaster.
To read more click here...
Feb 23, 2012
 |
| Girl Scouts in Phoenix work on the Electronic Matching Game, one of 22 Agilent After School kits. Photo: Agilent |
In order for technology companies to bring innovative products to market, they need enthusiastic, educated scientists and engineers to drive the process. To inspire the next generation of researchers, some industrial developers are going back to school.
A 2011 Harvard University study found that U.S. students ranked behind 31 other countries in math and science efficiency, and fewer than one in three students are proficient in science after high school.
A recent teleconference held in October by STEM Connects, a curriculum and career development resource from Discovery Education—an educational resource for teachers—reported that 10 to 15% of students in the U.S. enter college as science, technology, engineering, or mathematics (STEM) majors; in China that number is 30 to 40%, paving the way for a scientific and technological advantage for that nation.
"I think people need to realize that a lack of students going into STEM fields not only affects the learning curves in schools, but it also affects our global competitiveness and our ability as a nation to innovate," says Jennifer Harper-Taylor, president of the Siemens Foundation, Iselin, N.J. "If we don’t have a smart workforce, we are not going to have sophisticated R&D happening."
To drive more interest to these fields, industrial companies are helping students understand the importance of science and mathematics, and are promoting STEM education and innovation to the next generation.
From school to scientific discovery
"One of the keys to innovation is engaging the future scientists and engineers of our nation," says Tom Buckmaster, president of Honeywell Hometown Solutions, Morris Township, N.J. "The more students that have an interest in science and math means the possibility of more scientists and engineers our society could have, which will expand our nation’s capacity for innovation."
Agilent Technologies Inc., Santa Clara, Calif., promotes hands-on learning to enhance understanding of basic science concepts. The company has created the Agilent After School program, a hands-on, experimental science program targeted at children from the ages 9 to 13. The program has reached 550,000 students globally; and Agilent has invested around $3.5 million in the program in the past 10 years.
The program features 22 kits or projects that range from simple experiments for elementary school students, to more complex experiments that require advanced critical thinking and measurement skills for high school students. Projects include creating electronic circuit boards and balloon- or solar-powered cars, learning how to clean up oil spills, and solving a crime scene mystery. Held at universities and other local facilities, Agilent employees teach the students the basics about their projects and what they are creating, providing the students with knowledge that they can take back to their classrooms.
"Students really love the hands-on aspect of the projects, and in turn love leaving with what they built," says Terry Lincoln, Agilent Technologies’ global signature programs manager. "They also love the engagement between themselves and the employee running the program and talking about their project, making them want to take their projects outside of the program and into the classroom."
Science hits the road
Morris Township, N.J.-based Honeywell International has partnered with NASA to create FMA Live!, a program that explains Sir Isaac Newton's laws of motion in an exciting and entertaining way. The MTV-style interactive traveling show teaches basic science concepts and engages future engineers and scientists in the seventh to ninth grades.
FMA Live! features high-energy actors, music, videos, and demonstrations to teach Newton's laws of motion and the process of scientific inquiry. During each performance, students, teachers, and school administrators interact with three professional actors on stage in front of a live audience.
The actors use a large Velcro wall to demonstrate inertia when a student jumps off a springboard and is immediately stuck to the wall. Go-carts race across the stage to illustrate action and reaction. Extreme wrestling and a giant soccer ball show how force equals mass multiplied by acceleration. All three laws are shown simultaneously when a participant—usually a teacher or administrator—rides a futuristic hover chair and collides face first with a gigantic cream pie, exciting the students and providing lasting and memorable lessons, says Buckmaster.
To read more click here...
Smaller antennas for smaller wireless devices and still smaller micro-air vehicles
Engineerblogger
Feb 23, 2012
In most cases the size of the antenna within a wireless device is actually the limiting factor in the minimum achievable size of the device itself. As such, manufacturers must "build up" to the required antenna size. Dr. Grbic's team provides a way for manufacturers to either "build down" to a much smaller size, or with a smaller antenna, to allow additional room for more capabilities with built-in options.
Supported by a Presidential Early Career Award for Scientists and Engineers through the Air Force Office of Scientific Research, Dr. Anthony Grbic utilizes an innovative fabrication process to produce small, efficient antennas.
When you thought our hand held electronic devices could not get any smaller or more efficient, along comes Dr. Anthony Grbic and his research team from the Department of Electrical Engineering and Computer Science at the University of Michigan, with an antenna the size of an quarter.
You may ask: why is this significant? Dr. Grbic, and his colleague Dr. Stephen Forrest, point out that in most cases the size of the antenna within a wireless device is actually the limiting factor in the minimum achievable size of the device itself. As such, manufacturers must "build up" to the required antenna size. Dr. Grbic's team provides a way for manufacturers to either "build down" to a much smaller size, or with a smaller antenna, to allow additional room for more capabilities with built-in options.
The key to this new design is the hemispherical shape of the antenna which takes advantage of volume—just imagine the top half of a sphere with a descending spiral antenna winding down to the base—instant miniaturization. Dr. Grbic notes that this hemispherical antenna concept had been around for several years, but there was no practical way to mass produce the spiral antenna pattern. The Grbic and Forrest teams overcame this obstacle with a simple metallic stamping process which is very quick, efficient and potentially inexpensive, while maintaining the same bandwidth as their larger counterparts.
Currently this antenna design operates in only one frequency band, so the next step is to make the antenna operate in multiple frequency bands for use in multiple applications. Talks are also underway with Bluetooth and WiFi communications manufacturers to utilize this new technology. Of particular interest to the Air Force is the integration of these small and highly efficient antennas on autonomous micro-air vehicles, and taking this process one step further, the technique could be applied to the manufacture of conformal antennas that could be integrated onto the surface of an air vehicle—conforming to their low profile stealth design.
Source: Air Force Office of Scientific Research
Feb 23, 2012
In most cases the size of the antenna within a wireless device is actually the limiting factor in the minimum achievable size of the device itself. As such, manufacturers must "build up" to the required antenna size. Dr. Grbic's team provides a way for manufacturers to either "build down" to a much smaller size, or with a smaller antenna, to allow additional room for more capabilities with built-in options.
Supported by a Presidential Early Career Award for Scientists and Engineers through the Air Force Office of Scientific Research, Dr. Anthony Grbic utilizes an innovative fabrication process to produce small, efficient antennas.
When you thought our hand held electronic devices could not get any smaller or more efficient, along comes Dr. Anthony Grbic and his research team from the Department of Electrical Engineering and Computer Science at the University of Michigan, with an antenna the size of an quarter.
You may ask: why is this significant? Dr. Grbic, and his colleague Dr. Stephen Forrest, point out that in most cases the size of the antenna within a wireless device is actually the limiting factor in the minimum achievable size of the device itself. As such, manufacturers must "build up" to the required antenna size. Dr. Grbic's team provides a way for manufacturers to either "build down" to a much smaller size, or with a smaller antenna, to allow additional room for more capabilities with built-in options.
The key to this new design is the hemispherical shape of the antenna which takes advantage of volume—just imagine the top half of a sphere with a descending spiral antenna winding down to the base—instant miniaturization. Dr. Grbic notes that this hemispherical antenna concept had been around for several years, but there was no practical way to mass produce the spiral antenna pattern. The Grbic and Forrest teams overcame this obstacle with a simple metallic stamping process which is very quick, efficient and potentially inexpensive, while maintaining the same bandwidth as their larger counterparts.
Currently this antenna design operates in only one frequency band, so the next step is to make the antenna operate in multiple frequency bands for use in multiple applications. Talks are also underway with Bluetooth and WiFi communications manufacturers to utilize this new technology. Of particular interest to the Air Force is the integration of these small and highly efficient antennas on autonomous micro-air vehicles, and taking this process one step further, the technique could be applied to the manufacture of conformal antennas that could be integrated onto the surface of an air vehicle—conforming to their low profile stealth design.
Source: Air Force Office of Scientific Research
Value Stream Analysis Improves Processes, Saves Money
Engineerblogger
Feb 23, 2012
Engineers from the Air Force Research Laboratory have stimulated industrial base investments in infrastructure and technology by leveraging the value stream analysis (VSA) process to identify significant process improvement opportunities.
As a result, General Electric Aviation, Pratt & Whitney and Rolls Royce, together with some of their suppliers, invested in process improvements to produce an expected $34 million cost avoidance for current and future products. Because many of the manufacturing technologies are applicable to advanced turbine engine performance improvements, the potential for an additional $126 million cost avoidance for current projects exists.
For the last five years, AFRL's Manufacturing Technology Division (AFRL/RXM), in cooperation with General Dynamics Information Technology and TechSolve, Inc., has been conducting VSAs within the advanced turbine engine industrial base. Each VSA generated a list of potential process improvements, projected costs, and assessed the risks associated with achieving the anticipated benefits.
AFRL/RXM used the data from these VSAs to develop successful ManTech programs, including a program for the advanced machining of CMCs. This program yielded increases in material removal rates and a reduction in cutting tool costs by two orders of magnitude. Additionally, the 3D airfoil inspection process reduced the dimensional inspection of complex shapes from 60 minutes down to 3 minutes.
Industry has used this data to pursue lower risk process improvements. These process improvements have been implemented and are anticipated to yield benefits of $27 million. Process improvements that have been partially implemented through industry investment are anticipated to yield an additional $7 million. When implemented, processes that are still maturing could provide an additional $126 million in benefits. For industry, the return on investment is about 15 to 1 and it is even greater for the Air Force, at 28 to 1.
Source: Air Force Office of Scientific Research
Feb 23, 2012
 |
| An example Pareto chart from a value stream analysis shows the potential benefit of implementing VSA findings. (AFRL Graphic) |
Engineers from the Air Force Research Laboratory have stimulated industrial base investments in infrastructure and technology by leveraging the value stream analysis (VSA) process to identify significant process improvement opportunities.
As a result, General Electric Aviation, Pratt & Whitney and Rolls Royce, together with some of their suppliers, invested in process improvements to produce an expected $34 million cost avoidance for current and future products. Because many of the manufacturing technologies are applicable to advanced turbine engine performance improvements, the potential for an additional $126 million cost avoidance for current projects exists.
For the last five years, AFRL's Manufacturing Technology Division (AFRL/RXM), in cooperation with General Dynamics Information Technology and TechSolve, Inc., has been conducting VSAs within the advanced turbine engine industrial base. Each VSA generated a list of potential process improvements, projected costs, and assessed the risks associated with achieving the anticipated benefits.
AFRL/RXM used the data from these VSAs to develop successful ManTech programs, including a program for the advanced machining of CMCs. This program yielded increases in material removal rates and a reduction in cutting tool costs by two orders of magnitude. Additionally, the 3D airfoil inspection process reduced the dimensional inspection of complex shapes from 60 minutes down to 3 minutes.
Industry has used this data to pursue lower risk process improvements. These process improvements have been implemented and are anticipated to yield benefits of $27 million. Process improvements that have been partially implemented through industry investment are anticipated to yield an additional $7 million. When implemented, processes that are still maturing could provide an additional $126 million in benefits. For industry, the return on investment is about 15 to 1 and it is even greater for the Air Force, at 28 to 1.
Source: Air Force Office of Scientific Research
Materials: Graphene Is Thinnest Known Anti-Corrosion Coating
Engineerblogger
Feb 23, 2012
New research has established the "miracle material" called graphene as the world's thinnest known coating for protecting metals against corrosion. Their study on this potential new use of graphene appears in ACS Nano.
In the study, Dhiraj Prasai and colleagues point out that rusting and other corrosion of metals is a serious global problem, and intense efforts are underway to find new ways to slow or prevent it. Corrosion results from contact of the metal's surface with air, water or other substances. One major approach involves coating metals with materials that shield the metal surface, but currently used materials have limitations. The scientists decided to evaluate graphene as a new coating. Graphene is a single layer of carbon atoms, many layers of which are in lead pencils and charcoal, and is the thinnest, strongest known material. That's why it is called the miracle material. In graphene, the carbon atoms are arranged like a chicken-wire fence in a layer so thin that is transparent, and an ounce would cover 28 football fields.
They found that graphene, whether made directly on copper or nickel or transferred onto another metal, provides protection against corrosion. Copper coated by growing a single layer of graphene through chemical vapor deposition (CVD) corroded seven times slower than bare copper, and nickel coated by growing multiple layers of graphene corroded 20 times slower than bare nickel. Remarkably, a single layer of graphene provides the same corrosion protection as conventional organic coatings that are more than five times thicker. Graphene coatings could be ideal corrosion-inhibiting coatings in applications where a thin coating is favorable, such as microelectronic components (e.g., interconnects, aircraft components and implantable devices), say the scientists.
The researchers acknowledge funding from the National Science Foundation.
Source: American Chemical Society (ASC)
Additional Information:
Feb 23, 2012
 |
In the study, Dhiraj Prasai and colleagues point out that rusting and other corrosion of metals is a serious global problem, and intense efforts are underway to find new ways to slow or prevent it. Corrosion results from contact of the metal's surface with air, water or other substances. One major approach involves coating metals with materials that shield the metal surface, but currently used materials have limitations. The scientists decided to evaluate graphene as a new coating. Graphene is a single layer of carbon atoms, many layers of which are in lead pencils and charcoal, and is the thinnest, strongest known material. That's why it is called the miracle material. In graphene, the carbon atoms are arranged like a chicken-wire fence in a layer so thin that is transparent, and an ounce would cover 28 football fields.
They found that graphene, whether made directly on copper or nickel or transferred onto another metal, provides protection against corrosion. Copper coated by growing a single layer of graphene through chemical vapor deposition (CVD) corroded seven times slower than bare copper, and nickel coated by growing multiple layers of graphene corroded 20 times slower than bare nickel. Remarkably, a single layer of graphene provides the same corrosion protection as conventional organic coatings that are more than five times thicker. Graphene coatings could be ideal corrosion-inhibiting coatings in applications where a thin coating is favorable, such as microelectronic components (e.g., interconnects, aircraft components and implantable devices), say the scientists.
The researchers acknowledge funding from the National Science Foundation.
Source: American Chemical Society (ASC)
Additional Information:
- Graphene: Corrosion-Inhibiting Coating, ACS Nano, Article ASAP. DOI: 10.1021/nn203507y
Ferroelectric Nanotubes: “Soft Template Infiltration” Technique Fabricates Free-Standing Piezoelectric Nanostructures from PZT Material
Georgia Tech
Feb 23, 2012
Researchers have developed a “soft template infiltration” technique for fabricating free-standing piezoelectrically active ferroelectric nanotubes and other nanostructures from PZT – a material that is attractive because of its large piezoelectric response. Developed at the Georgia Institute of Technology, the technique allows fabrication of ferroelectric nanostructures with user-defined shapes, location and pattern variation across the same substrate.
The resulting structures, which are 100 to 200 nanometers in outer diameter with thickness ranging from 5 to 25 nanometers, show a piezoelectric response comparable to that of PZT thin films of much larger dimensions. The technique could ultimately lead to production of actively-tunable photonic and phononic crystals, terahertz emitters, energy harvesters, micromotors, micropumps and nanoelectromechanical sensors, actuators and transducers – all made from the PZT material.
Using a novel characterization technique developed at Oak Ridge National Laboratory, the researchers for the first time made high-accuracy in-situ measurements of the nanoscale piezoelectric properties of the structures.
“We are using a new nano-manufacturing method for creating three-dimensional nanostructures with high aspect ratios in ferroelectric materials that have attractive piezoelectric properties,” said Nazanin Bassiri-Gharb, an assistant professor in Georgia Tech’s Woodruff School of Mechanical Engineering. “We also leveraged a new characterization method available through Oak Ridge to study the piezoelectric response of these nanostructures on the substrate where they were produced.”
The research was published online on Jan. 26, 2012, and is scheduled for publication in the print edition (Vol. 24, Issue 9) of the journal Advanced Materials. The research was supported by Georgia Tech new faculty startup funds.
Ferroelectric materials at the nanometer scale are promising for a wide range of applications, but processing them into useful devices has proven challenging – despite success at producing such devices at the micrometer scale. Top-down manufacturing techniques, such as focused ion beam milling, allow accurate definition of devices at the nanometer scale, but the process can induce surface damage that degrades the ferroelectric and piezoelectric properties that make the material interesting.
Until now, bottom-up fabrication techniques have been unable to produce structures with both high aspect ratios and precise control over location. The technique reported by the Georgia Tech researchers allows production of nanotubes made from PZT (PbZr0.52Ti0.48O3) with aspect ratios of up to 5 to 1.
To read more click here...
Feb 23, 2012
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| Composite scanning electron microscope (SEM) image of PZT nanotube arrays and their piezoelectric response as measured by band-excitation PFM (BE-PFM). (Click image for high-resolution version. Image courtesy of Ashley Bernal and Nazanin Bassiri-Gharb) |
Researchers have developed a “soft template infiltration” technique for fabricating free-standing piezoelectrically active ferroelectric nanotubes and other nanostructures from PZT – a material that is attractive because of its large piezoelectric response. Developed at the Georgia Institute of Technology, the technique allows fabrication of ferroelectric nanostructures with user-defined shapes, location and pattern variation across the same substrate.
The resulting structures, which are 100 to 200 nanometers in outer diameter with thickness ranging from 5 to 25 nanometers, show a piezoelectric response comparable to that of PZT thin films of much larger dimensions. The technique could ultimately lead to production of actively-tunable photonic and phononic crystals, terahertz emitters, energy harvesters, micromotors, micropumps and nanoelectromechanical sensors, actuators and transducers – all made from the PZT material.
Using a novel characterization technique developed at Oak Ridge National Laboratory, the researchers for the first time made high-accuracy in-situ measurements of the nanoscale piezoelectric properties of the structures.
“We are using a new nano-manufacturing method for creating three-dimensional nanostructures with high aspect ratios in ferroelectric materials that have attractive piezoelectric properties,” said Nazanin Bassiri-Gharb, an assistant professor in Georgia Tech’s Woodruff School of Mechanical Engineering. “We also leveraged a new characterization method available through Oak Ridge to study the piezoelectric response of these nanostructures on the substrate where they were produced.”
The research was published online on Jan. 26, 2012, and is scheduled for publication in the print edition (Vol. 24, Issue 9) of the journal Advanced Materials. The research was supported by Georgia Tech new faculty startup funds.
Ferroelectric materials at the nanometer scale are promising for a wide range of applications, but processing them into useful devices has proven challenging – despite success at producing such devices at the micrometer scale. Top-down manufacturing techniques, such as focused ion beam milling, allow accurate definition of devices at the nanometer scale, but the process can induce surface damage that degrades the ferroelectric and piezoelectric properties that make the material interesting.
Until now, bottom-up fabrication techniques have been unable to produce structures with both high aspect ratios and precise control over location. The technique reported by the Georgia Tech researchers allows production of nanotubes made from PZT (PbZr0.52Ti0.48O3) with aspect ratios of up to 5 to 1.
To read more click here...
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