OREGON STATE UNIVERSITY

college of engineering

“Community solar” systems may add savings to local, cooperative energy projects

CORVALLIS, Ore. – Part of the future of solar energy, especially for residential use, may be small “community-based” systems in which neighbors join together in the construction and use of solar systems to optimize the energy produced in their neighborhood – and share in the benefits.

New research by engineers at Oregon State University indicate that an optimal development of neighborhood solar energy might increase the total electricity produced by 5-10 percent, a significant gain by the standards of solar energy efficiency. At the same time, it can reduce the variability and unpredictability of the solar resource.

With this approach, the use of various rooftops and land used for solar energy production may vary from house to house, depending upon such issues as the home’s orientation, roof slope and shading from trees or other structures. Quite simply, some structures lend themselves better than others to solar energy.

“An approach such as this makes the most sense in a neighborhood where there’s a lot of variation in terms of sun and shadow, and the orientation of buildings,” said Mahmoud Shakouri, a doctoral candidate in the OSU College of Engineering.

“The conventional approach to residential solar energy is to look at each home as an individual package, building its own solar system whether or not that’s a good location. But by grouping 10 or 20 houses in a neighborhood, all of whose owners are interested in solar energy, we can optimize the use and placement of solar panels and let everyone share in the savings.”

The idea has been considered for some time, Shakouri said, but failed to generate much headway in the United States due to limited interest in solar energy, high initial costs, and tax credits or incentives that fail to recognize this approach to optimizing the solar resource.

Findings on this issue have been published recently in the journals of Applied Energy and Data in Brief, and a “decision support model” has been created that homeowners could use to help consider the best options for their neighborhood. Free software to help implement such a strategy is also available from the U.S. Department of Energy. Collaborating on this research was Hyun Woo Lee at the University of Washington.

Initial solar installations can be expensive, making it all the more important to maximize the long-term output of the systems. But such systems are also durable and pollution free, usually with a performance guarantee of up to 25 years, using a technology that produces no greenhouse gases.

Residential energy use is also a big-ticket item – in the United States, the building sector accounts for 40 percent of total energy consumption, and residential buildings consume more than half of the energy in the building sector. By 2035, the federal government estimates that 74 percent of the energy consumed in residences will be in the form of electricity, even as two thirds of the nation’s electricity is still produced by coal or natural gas that are helping to cause global warming.

The new approach developed at OSU, Shakouri said, actually borrows formulas from economic theory. This approach has long been used in the stock market in the form of portfolio investment, to maximize profit while reducing risks. Given the high initial cost of some solar systems – averaging about $20,000 for a 4 kilowatt residential system – reducing risk is of considerable value to many people interested in the technology.

Studies done at OSU included a case study of collaborative solar energy among 24 homes in a neighborhood in Corvallis, Ore., which has sunny summers but often-cloudy and rainy winters, not exactly the nation’s best bet in terms of solar energy production. Even there, this approach increased the annual electricity output of the homes by 4.6 percent and reduced the volatility in electrical output by 4.3 percent.

Use of approaches such as this may become more common as the efficiency of solar technology improves, more people become aware of its potential, and legislation or policies are changed to better enable community solar projects, researchers say. More work is also needed to determine how to contractually share expenses, profits and benefits among cooperating neighbors.

Story By: 
Source: 

Mahmoud Shakouri

shakourm@oregonstate.edu

 

Multimedia Downloads
Multimedia: 

Bayview Home
Residential solar energy

Wetland enhancement in Midwest could help reduce catastrophic floods of the future

CORVALLIS, Ore. – According to a new study from Oregon State University, restoration of wetlands in the Midwest has the potential to significantly reduce peak river flows during floods - not only now, but also in the future if heavy rains continue to increase in intensity.

Wetland restoration could also provide a small step toward a hydrologic regime in this region that more closely resembles its historic nature, before roads and cities were constructed, forests were lost, and millions of acres tile-drained to increase agricultural production.

An evaluation of potential wetlands in one watershed in central Indiana found that if just 1.5 percent of the land were used for wetlands, the peak flow of the overall watershed could be reduced by up to 17.5 percent. Also of importance, researchers said, is that expansion of wetlands appears to provide significant benefits across a wide range of possible climate scenarios.

The study was published in Ecological Engineering, in work supported by the National Science Foundation and the National Oceanic and Atmospheric Administration.

“Flood management in the Midwest is now almost entirely concentrated on use of dams and levees,” said Meghna Babbar-Sebens, an assistant professor of civil engineering in the College of Engineering, and the Eric H.I. and Janice Hoffman Faculty Scholar at OSU.

“Wetland construction or restoration could provide a natural and ecological option to help with flood concerns, and serve as an additional tool for flood management. Greater investments in this approach, or similar approaches that increase storage of water in the upper landscape of a watershed, should be seriously considered.”

The new research considered not just the problem now – which is serious – but what the future may bring.

The study used climate models supported by the North American Regional Climate Change Assessment Program, along with a hydrology model to examine the impact of wetlands during the climate scenarios for a mid-century period from 2041 to 2070. It suggests this central Indiana region could see continued increases in extreme events, such as more extremely hot days during summer and more heavy rain in the wettest 5-day periods.

“There’s some variation in the models, but there’s general agreement that the future will bring more heavy precipitation events,” Babbar-Sebens said. “How we transfer and store runoff on the landscape is going to become even more critical.”

“From the perspective of a decision maker, an advantage of wetland construction is that it would significantly reduce flooding from heavy precipitation in almost every possible scenario. Wetlands are consistently effective.”

An obstacle at this point, she said, is that many incentive programs that support wetland restoration and creation usually focus on ecology, wildlife enhancement and water quality issues – and there are limited funding mechanisms to create upland wetlands for flood management. This limits the economic incentives for farmers and landowners to set aside room for wetlands, especially with the high price of agricultural crops.

New financial models and flood management policies would probably be needed to address this, Babbar-Sebens said.

Deforestation, agriculture and the historic growth of cities with impervious infrastructure have hugely changed the face of the Midwest and its hydrology, leading to frequent floods.

Climate change is now exacerbating that problem. In 2011, Indiana experienced record-breaking heat in seven counties, record-breaking rainfall in 22 counties, and record-breaking snowfall in six counties. The state has been declared a flood disaster area 14 times between 2000 and 2011, compared to only four times in the decade prior to that.

The great Mississippi River flood of 2011 was considered a “500-year event” and caused $2.8 billion in damage. It flooded more than 21,000 homes and businesses and 1.2 million acres of agricultural land, according to a report from the U.S. Army Corps of Engineers.

Wetlands help reduce some of these flooding problems by storing water away from stream channels and releasing it more slowly, while also improving water quality and providing wildlife habitat. Other studies have shown that wetland construction in the Mississippi-Ohio-Missouri river basins could also significantly reduce nitrogen loads in the rivers, which has led to an enormous “dead zone” in the Gulf of Mexico.

A methodology for evaluating wetlands with respect to historic climate and future climate scenarios, created in this research, should be applicable to other watersheds in the Midwest, researchers said.

Story By: 
Source: 

Meghna Babbar-Sebens, 541-737-8536

Multimedia Downloads
Multimedia: 

Wetlands
River wetlands

Oregon State launches humanitarian engineering program

CORVALLIS, Ore. - The Oregon State University College of Engineering has recently launched a humanitarian engineering program like few others in the nation, partly as a response to a growing number of students who want to make an impact both locally and globally.

Undergraduate students can now minor in this field, taking classes that emphasize the importance of socio-cultural, economic, environmental and resource management factors. Work in ethics, social justice and cross-cultural communication is also part of the program.

Humanitarian engineering emphasizes science and engineering-based solutions that help to improve the human condition, access to basic human needs, the quality of life or level of community resilience. OSU’s program is one of only a few in the nation based in an academic curriculum.

The program reflects an engaged concept of service and the university’s historic land grant mission, officials say. Through it, students will explore case studies of development projects and a historic perspective on humanitarian interventions.

One OSU student who understands that concept is Grace Burleson, a graduating senior majoring in mechanical engineering. She grew up as a missionary child and was raised by parents with a passion for helping underserved populations.

“When I got to college, I loved my engineering coursework but never got excited by applying it to things like cars or computers,” said Burleson. “I began research in humanitarian engineering and landed an internship in Uganda, working where I developed a sustainable business plan for the construction, distribution and maintenance of BioSand water filters.”                    

As a formalized academic program, humanitarian engineering will contribute to the effort of the OSU College of Engineering to become a recognized model as an inclusive and collaborative community.

“The program is attracting a more diverse group of prospective students than is typically attracted to engineering, including women,” said mechanical engineering professor Kendra Sharp, who directs the program, and was appointed the first Richard and Gretchen Evans Professor in Humanitarian Engineering.

OSU is also one of just 10 universities nationwide to offer a Peace Corps Master’s International program in engineering. The university was the first in Oregon to join this initiative, which allows graduate students in several disciplines to get a master’s degree while doing a full 27-month term of service in the Peace Corps.

Multiple student organizations, including Oregon State’s award-winning Engineers Without Borders chapter and the American Society of Civil Engineering student chapter, have also been working on water, energy and other projects in the developing world. 

“Students at Oregon State receive an accredited engineering degree, so adding on this minor opens many more doors and perspectives with how we look at engineering,” said Burleson. “It creates a gateway for really exciting and impactful projects.”

Media Contact: 

Krista Klinkhammer, 541-737-4416

Source: 

Kendra Sharp, 541-737-5246

Multimedia Downloads
Multimedia: 

Engineering outreach
Engineering study in Uganda

Thousands of landslides in Nepal earthquake raise parallels for Pacific Northwest

CORVALLIS, Ore. – Research teams have evaluated the major 7.8 magnitude subduction zone earthquake in Gorkha, Nepal, in April 2015, and identified some characteristics that may be of special relevance to the future of the Pacific Northwest.

Most striking was the enormous number and severity of landslides.

Many people understand the damage that can be caused to structures, roads, bridges and utilities by ground shaking in these long-lasting types of earthquakes, such as the one that’s anticipated on the Cascadia Subduction Zone between northern California and British Columbia.

But following the Nepal earthquake – even during the dry season when soils were the most stable – there were also tens of thousands of landslides in the region, according to reconnaissance team estimates. In their recent report published in Seismological Research Letters, experts said that these landslides caused pervasive damage as they buried towns and people, blocked rivers and closed roads.

Other estimates, based on the broader relationship between landslides and earthquake magnitude, suggest the Nepal earthquake might have caused between 25,000 and 60,000 landslides.

The subduction zone earthquake expected in the future of the Pacific Northwest is expected to be larger than the event in Nepal.

Ben Mason, a geotechnical engineer and assistant professor in the College of Engineering at Oregon State University, was a member of the Geotechnical Extreme Event Reconnaissance team that explored the Nepal terrain. He said that event made clear that structural damage is only one of the serious threats raised by subduction zone earthquakes.

“In the Coast Range and other hilly areas of Oregon and Washington, we should expect a huge number of landslides associated with the earthquake we face,” Mason said. “And in this region our soils are wet almost all year long, sometimes more than others. Each situation is different, but soils that are heavily saturated can have their strength cut in half.”

Wet soils will also increase the risk of soil liquefaction, Mason said, which could be pervasive in the Willamette Valley and many areas of Puget Sound, Seattle, Tacoma, and Portland, especially along the Columbia River.

Scientists have discovered that the last subduction zone earthquake to hit the Pacific Northwest was in January 1700, when – like now - soils probably would have been soggy from winter rains and most vulnerable to landslides.

The scientific study of slope stability is still a work in progress, Mason said, and often easier to explain after a landslide event has occurred than before it happens. But continued research on earthquake events such as those in Nepal may help improve the ability to identify areas most vulnerable to landslides, he said. Models can be improved and projections made more accurate.

“If you look just at the terrain in some parts of Nepal and remove the buildings and people, you could think you were looking at the Willamette Valley,” Mason said. “There’s a lot we can learn there.”

In Nepal, the damage was devastating.

Landslides triggered by ground shaking were the dominant geotechnical effect of the April earthquake, the researchers wrote in their report, as slopes weakened and finally gave way. Landslides caused by the main shock or aftershocks blocked roads, dammed rivers, damaged or destroyed villages, and caused hundreds of fatalities.

The largest and most destructive event, the Langtang debris avalanche, began as a snow and ice avalanche and gathered debris that became an airborne landslide surging off a 500-meter-tall cliff. An air blast from the event flattened the forest in the valley below, moved 2 million cubic meters of material and killed about 200 people.

Surveying the damages after the event, Mason said one of his most compelling impressions was the way people helped each other.

“Nepal is one of the poorest places, in terms of gross domestic product, that I’ve ever visited,” he said. “People are used to adversity, but they are culturally rich. After this event it was amazing how their communities bounced back, people helped treat each other’s injuries and saved lives. As we make our disaster plans in the Pacific Northwest, there are things we could learn from them, both about the needs for individual initiative and community response.”

Aside from landslides, many lives were lost in collapsing structures in Nepal, often in homes constructed of rock, brick or concrete, and frequently built without adequate enforcement of building codes, the report suggested. Overall, thousands of structures were destroyed. There are estimates that about 9,000 people died, and more than 23,000 were injured. The earthquake even triggered an avalanche on Mount Everest that killed at least 19 people.

The reconnaissance effort in Nepal was made possible by support from the National Science Foundation, the U.S. Geological Survey, the U.S. Agency for International Development, the OSU College of Engineering, and other agencies and universities around the world.

Story By: 
Source: 

Ben Mason, 541-737-2014

Multimedia Downloads
Multimedia: 

Nepal landslide
Nepal landslide

Tooth fillings of the future may incorporate bioactive glass

CORVALLIS, Ore. – A few years from now millions of people around the world might be walking around with an unusual kind of glass in their mouth, and using it every time they eat.

Engineers at Oregon State University have made some promising findings about the ability of “bioactive” glass to help reduce the ability of bacteria to attack composite tooth fillings – and perhaps even provide some of the minerals needed to replace those lost to tooth decay.

Prolonging the life of composite tooth fillings could be an important step forward for dental treatment, the researchers say, since more than 122 million composite tooth restorations are made in the United States every year. An average person uses their teeth for more than 600,000 “chews” a year, and some studies suggest the average lifetime of a posterior dental composite is only six years.

The new research was just published in the journal Dental Materials, in work supported by the National Institutes of Health.

“Bioactive glass, which is a type of crushed glass that is able to interact with the body, has been used in some types of bone healing for decades,” said Jamie Kruzic, a professor and expert in advanced structural and biomaterials in the OSU College of Engineering.

“This type of glass is only beginning to see use in dentistry, and our research shows it may be very promising for tooth fillings,” he said. “The bacteria in the mouth that help cause cavities don’t seem to like this type of glass and are less likely to colonize on fillings that incorporate it. This could have a significant impact on the future of dentistry.”

Bioactive glass is made with compounds such as silicon oxide, calcium oxide and phosphorus oxide, and looks like powdered glass. It’s called “bioactive” because the body notices it is there and can react to it, as opposed to other biomedical products that are inert. Bioactive glass is very hard and stiff, and it can replace some of the inert glass fillers that are currently mixed with polymers to make modern composite tooth fillings.

“Almost all fillings will eventually fail,” Kruzic said. “New tooth decay often begins at the interface of a filling and the tooth, and is called secondary tooth decay. The tooth is literally being eroded and demineralized at that interface.”

Bioactive glass may help prolong the life of fillings, researchers say, because the new study showed that the depth of bacterial penetration into the interface with bioactive glass-containing fillings was significantly smaller than for composites lacking the glass.

Fillings made with bioactive glass should slow secondary tooth decay, and also provide some minerals that could help replace those being lost, researchers say. The combination of these two forces should result in a tooth filling that works just as well, but lasts longer.

Recently extracted human molars were used in this research to produce simulated tooth restoration samples for laboratory experiments. OSU has developed a laboratory that’s one of the first in the world to test simulated tooth fillings in conditions that mimic the mouth.

If this laboratory result is confirmed by clinical research, it should be very easy to incorporate bioactive glass into existing formulations for composite tooth fillings, Kruzic said.

The antimicrobial effect of bioactive glass is attributed, in part, to the release of ions such as those from calcium and phosphate that have a toxic effect on oral bacteria and tend to neutralize the local acidic environment.

“My collaborators and I have already shown in previous studies that composites containing up to 15 percent bioactive glass, by weight, can have mechanical properties comparable, or superior to commercial composites now being used,” Kruzic said.

This work was done in collaboration with researchers from the School of Dentistry at the Oregon Health & Science University and the College of Dental Medicine at Midwestern University.

Story By: 
Source: 

Jamie Kruzic, 541-737-7027

Multimedia Downloads
Multimedia: 

Bioactive glass
Bioactive glass

Photonic “sintering” may create new solar, electronics manufacturing technologies

CORVALLIS, Ore. – Engineers at Oregon State University have made a fundamental breakthrough in understanding the physics of photonic “sintering,” which could lead to many new advances in solar cells, flexible electronics, various types of sensors and other high-tech products printed onto something as simple as a sheet of paper or plastic.

Sintering is the fusing of nanoparticles to form a solid, functional thin-film that can be used for many purposes, and the process could have considerable value for new technologies.

Photonic sintering has the possible advantage of higher speed and lower cost, compared to other technologies for nanoparticle sintering.

In the new research, OSU experts discovered that previous approaches to understand and control photonic sintering had been based on a flawed view of the basic physics involved, which had led to a gross overestimation of product quality and process efficiency.

Based on the new perspective of this process, which has been outlined in Nature Scientific Reports, researchers now believe they can create high quality products at much lower temperatures, at least twice as fast and with 10 times more energy efficiency.

Removing constraints on production temperatures, speed and cost, the researchers say, should allow the creation of many new high-tech products printed onto substrates as cheap as paper or plastic wrap.

“Photonic sintering is one way to deposit nanoparticles in a controlled way and then join them together, and it’s been of significant interest,” said Rajiv Malhotra, an assistant professor of mechanical engineering in the OSU College of Engineering. “Until now, however, we didn’t really understand the underlying physics of what was going on. It was thought, for instance, that temperature change and the degree of fusion weren’t related – but in fact that matters a lot.”

With the concepts outlined in the new study, the door is open to precise control of temperature with smaller nanoparticle sizes. This allows increased speed of the process and high quality production at temperatures at least two times lower than before. An inherent “self-damping” effect was identified that has a major impact on obtaining the desired quality of the finished film.

“Lower temperature is a real key,” Malhotra said. “To lower costs, we want to print these nanotech products on things like paper and plastic, which would burn or melt at higher temperatures. We now know that is possible, and how to do it. We should be able to create production processes that are both fast and cheap, without a loss of quality.”

Products that could evolve from the research, Malhotra said, include solar cells, gas sensors, radiofrequency identification tags, and a wide range of flexible electronics. Wearable biomedical sensors could emerge, along with new sensing devices for environmental applications.

In this technology, light from a xenon lamp can be broadcast over comparatively large areas to fuse nanoparticles into functional thin films, much faster than with conventional thermal methods. It should be possible to scale up the process to large manufacturing levels for industrial use.

This advance was made possible by a four-year, $1.5 million National Science Foundation Scalable Nanomanufacturing Grant, which focuses on transcending the scientific barriers to industry-level production of nanomaterials. Collaborators at OSU include Chih-hung Chang, Alan Wang and Greg Herman.

OSU researchers will work with two manufacturers in private industry to create a proof-of-concept facility in the laboratory, as the next step in bringing this technology toward commercial production.

Story By: 
Source: 

Discovery could open door to frozen preservation of tissues, whole organs

CORVALLIS, Ore. – Researchers in the College of Engineering at Oregon State University have discovered a new approach to “vitrification,” or ice-free cryopreservation, that could ultimately allow a much wider use of extreme cold to preserve tissues and even organs for later use.

The findings were announced today in PLOS ONE, in work supported by the National Science Foundation.

“This could be an important step toward the preservation of more complex tissues and structures,” said Adam Higgins, an associate professor in the OSU School of Chemical, Biological and Environmental Engineering, and expert on medical bioprocessing.

Cryopreservation has already found widespread use in simpler applications such as preserving semen, blood, embryos, plant seeds and some other biological applications. But it is often constrained by the crystallization that occurs when water freezes, which can damage or destroy tissues and cells, Higgins said. This is similar to what happens to some food products when they are stored in a freezer, and lose much of their texture when thawed.

To address this, researchers have used various types of cryoprotectants that help reduce cell damage during the freezing process – among them is ethylene glycol, literally the same compound often used in automobile radiators to prevent freezing.

A problem, Higgins said, is that many of these cryoprotectants are toxic, and can damage or kill the very cells they are trying to protect from the forces of extreme cold.

In the new OSU research, the engineers developed a mathematical model to simulate the freezing process in the presence of cryoprotectants, and identified a way to minimize damage. They found that if cells are initially exposed to a low concentration of cryoprotectant and time is allowed for the cells to swell, then the sample can be vitrified after rapidly adding a high concentration of cryoprotectants. The end result is much less overall toxicity, Higgins said.

The research showed that healthy cell survival following vitrification rose from about 10 percent with a conventional approach to more than 80 percent with the new optimized procedure.

“The biggest single problem and limiting factor in vitrification is cryoprotectant toxicity, and this helps to address that,” Higgins said. “The model should also help us identify less toxic cryoprotectants, and ultimately open the door to vitrification of more complex tissues and perhaps complete organs.”

If that were possible, many more applications of vitrification could be feasible, especially as future progress is made in the rapidly advancing field of tissue regeneration, in which stem cells can be used to grow new tissues or even organs.

Tissues could be made in small amounts and then stored until needed for transplantation. Organs being used for transplants could be routinely preserved until a precise immunological match was found for their use. Conceptually, a person could even grow a spare heart or liver from their own stem cells and preserve it through vitrification in case it was ever needed, Higgins said.

Important applications might also be found in new drug development.

Drug testing is now carried out with traditional cell culture systems or animal models, which in many cases don’t accurately predict the effect of the drug in humans. To address this, researchers are developing “organs-on-a-chip,” or microfluidic chambers that contain human cells cultured under conditions that mimic native tissues or organs.

These new “organ-on-a-chip” systems may be able to more accurately predict drug responses in humans, but to deploy them, cells must be preserved in long-term storage. The new research could help address this by making it possible to store the systems in a vitrified state.

Story By: 
Source: 

Adam Higgins, 541-737-6245

Storage advance may boost solar thermal energy potential

CORVALLIS, Ore. – Engineers at Oregon State University have identified a new approach for the storage of concentrated solar thermal energy, to reduce its cost and make it more practical for wider use.

The advance is based on a new innovation with thermochemical storage, in which chemical transformation is used in repeated cycles to hold heat, use it to drive turbines, and then be re-heated to continue the cycle. Most commonly this might be done over a 24-hour period, with variable levels of solar-powered electricity available at any time of day, as dictated by demand.

The findings have been published in ChemSusChem, a professional journal covering sustainable chemistry. The work was supported by the SunShot Initiative of the U.S. Department of Energy, and done in collaboration with researchers at the University of Florida.

Conceptually, all of the energy produced could be stored indefinitely and used later when the electricity is most needed. Alternatively, some energy could be used immediately and the rest stored for later use.

Storage of this type helps to solve one of the key factors limiting the wider use of solar energy – by eliminating the need to use the electricity immediately. The underlying power source is based on production that varies enormously, not just night and day, but some days, or times of day, that solar intensity is more or less powerful. Many alternative energy systems are constrained by this lack of dependability and consistent energy flow.

Solar thermal electricity has been of considerable interest because of its potential to lower costs. In contrast to conventional solar photovoltaic cells that produce electricity directly from sunlight, solar thermal generation of energy is developed as a large power plant in which acres of mirrors precisely reflect sunlight onto a solar receiver. That energy has been used to heat a fluid that in turn drives a turbine to produce electricity.

Such technology is appealing because it’s safe, long-lasting, friendly to the environment and produces no greenhouse gas emissions. Cost, dependability and efficiency have been the primary constraints.

“With the compounds we’re studying, there’s significant potential to lower costs and increase efficiency,” said Nick AuYeung, an assistant professor of chemical engineering in the OSU College of Engineering, corresponding author on this study, and an expert in novel applications and use of sustainable energy.

“In these types of systems, energy efficiency is closely related to use of the highest temperatures possible,” AuYeung said. “The molten salts now being used to store solar thermal energy can only work at about 600 degrees centigrade, and also require large containers and corrosive materials. The compound we’re studying can be used at up to 1,200 degrees, and might be twice as efficient as existing systems.

“This has the potential for a real breakthrough in energy storage,” he said.

According to AuYeung, thermochemical storage resembles a battery, in which chemical bonds are used to store and release energy – but in this case, the transfer is based on heat, not electricity.

The system hinges on the reversible decomposition of strontium carbonate into strontium oxide and carbon dioxide, which consumes thermal energy. During discharge, the recombination of strontium oxide and carbon dioxide releases the stored heat. These materials are nonflammable, readily available and environmentally safe.

In comparison to existing approaches, the new system could also allow a 10-fold increase in energy density – it’s physically much smaller and would be cheaper to build.

The proposed system would work at such high temperatures that it could first be used to directly heat air which would drive a turbine to produce electricity, and then residual heat could be used to make steam to drive yet another turbine.

In laboratory tests, one concern arose when the energy storage capacity of the process declined after 45 heating and cooling cycles, due to some changes in the underlying materials. Further research will be needed to identify ways to reprocess the materials or significantly extend the number of cycles that could be performed before any reprocessing was needed, AuYeung said.

Other refinements may also be necessary to test the system at larger scales and resolve issues such as thermal shocks, he said, before a prototype could be ready for testing at a national laboratory.

Story By: 
Source: 

Nick AuYeung, 541-737-4600

Multimedia Downloads
Multimedia: 

Thermochemical energy
Thermal energy storage

“Spring-mass” technology heralds the future of walking robots

CORVALLIS, Ore. – A study by engineers at Oregon State University suggests that they have achieved the most realistic robotic implementation of human walking dynamics that has ever been done, which may ultimately allow human-like versatility and performance.

The system is based on a concept called “spring-mass” walking that was theorized less than a decade ago, and combines passive dynamics of a mechanical system with computer control. It provides the ability to blindly react to rough terrain, maintain balance, retain an efficiency of motion and essentially walk like humans do.

As such, this approach to robots that can walk and run like humans opens the door to entire new industries, jobs and mechanized systems that do not today exist.

The findings on spring-mass walking have been reported for the first time in IEEE Transactions on Robotics, by engineers from OSU and Germany. The work has been supported by the National Science Foundation, the Defense Advanced Research Projects Agency and the Human Frontier Science Program.

The technologies developed at OSU have evolved from intense studies of both human and animal walking and running, to learn how animals achieve a fluidity of motion with a high degree of energy efficiency. Animals combine a sensory input from nerves, vision, muscles and tendons to create locomotion that researchers have now translated into a working robotic system.

The system is also efficient. Studies done with their ATRIAS robot model, which incorporates the spring-mass theory, showed that it’s three times more energy-efficient than any other human-sized bipedal robots.

“I’m confident that this is the future of legged robotic locomotion,” said Jonathan Hurst, an OSU professor of mechanical engineering and director of the Dynamic Robotics Laboratory in the OSU College of Engineering.

“We’ve basically demonstrated the fundamental science of how humans walk,” he said.

“Other robotic approaches may have legs and motion, but don’t really capture the underlying physics,” he said. “We’re convinced this is the approach on which the most successful legged robots will work. It retains the substance and science of legged animal locomotion, and animals demonstrate performance that far exceeds any other approach we’ve seen. This is the way to go.”

The current technology, Hurst said, is still a crude illustration of what the future may hold. When further refined and perfected, walking and running robots may work in the armed forces. As fire fighters they may charge upstairs in burning buildings to save lives. They could play new roles in factories or do ordinary household chores.

Aspects of the locomotion technology may also assist people with disabilities, the researchers said.

“Robots are already used for gait training, and we see the first commercial exoskeletons on the market,” said Daniel Renjewski, the lead author on the study with the Technische Universitat Munchen. “However, only now do we have an idea how human-like walking works in a robot. This enables us to build an entirely new class of wearable robots and prostheses that could allow the user to regain a natural walking gait.” 

There are few limits to this technology, the researchers said.

“It will be some time, but we think legged robots will enable integration of robots into our daily lives,” Hurst said. “We know it is possible, based on the example of animals. So it’s inevitable that we will solve the problem with robots. This could become as big as the automotive industry.”

And much of this, the scientists said, will be based on the “spring-mass” concept, which animals have been perfecting through millions of years of evolution. 

The robots being constructed at OSU were designed to mimic this “spring-legged” action of bipedal animals. With minor variations, muscles, tendons and bones form a structure that exhibits most of the required behavior, and conscious control just nudges things a little to keep it going in the right direction. The effort is smooth and elastic, and once understood, can be simulated in walking robots by springs and other technology.

ATRIAS, the human-sized robot most recently created at OSU, has six electric motors powered by a lithium polymer battery about the size of a half-gallon of milk, which is substantially smaller than the power packs of some other mobile robots. It can take impacts and retain its balance. It can walk over rough and bumpy terrain.

Researchers said in their new study that this technology “has the potential to enhance legged robots to ultimately match the efficiency, agility and robustness of animals over a wide variety of terrain.”

In continued research, work will be done to improve steering, efficiency, leg configuration, inertial actuation, robust operation, external sensing, transmissions and actuators, and other technologies.

Other collaborators in the development of this technology have included Jessy Grizzle at the University of Michigan and Hartmut Geyer at Carnegie Mellon University. Scientific work on the motion of animals was done with Monica Daley at the Royal Veterinary College, which guided the robot’s development.

Story By: 
Source: 

Jonathan Hurst, 541-737-7010

Multimedia Downloads
Multimedia: 

A YouTube video is available of the walking robot: http://bit.ly/1HQKqOZ


Walking robot
Walking robot

Methodology could lead to more sustainable manufacturing systems

CORVALLIS, Ore. – Engineers at Oregon State University have developed a new “sustainable development methodology” to help address a social and regulatory demand for manufacturing processes that more effectively consider their economic, environmental and social impacts.

The work was recently published in the Journal of Cleaner Production. It outlines a way to help designers and manufacturing engineers carefully consider all the ramifications of their design decisions, and to evaluate the possible different ways that a product could be built – before it ever hits the assembly line.

“There’s a lot of demand by consumers, workers and companies who want to make progress on the sustainability of products and manufacturing processes,” said Karl Haapala, an associate professor in the OSU College of Engineering.

“There’s usually more than one way to build a part or product,” he said. “With careful analysis we can identify ways to determine which approach may have the least environmental impact, lowest cost, least waste, or other advantages that make it preferable to a different approach.”

This movement, researchers say, evolved more than 20 years ago from an international discussion at the United Nations Conference on Environment and Development, which raised concerns about the growing scarcity of water, depletion of non-renewable sources of energy, human health problems in the workplace, and other issues that can be linked to unsustainable production patterns in industry.

The challenge, experts say, is how to consider the well-being of employees, customers, and the community, all while producing a quality product and staying economically competitive. It isn’t easy, and comprehensive models that assess all aspects of sustainability are almost nonexistent.

“With current tools you can analyze various aspects of an operation one at a time, like the advantages of different materials, transportation modes, energy used, or other factors,” Haapala said. “It’s much more difficult to consider all of them simultaneously and come out with a reasonable conclusion about which approach is best.”

To aid that effort, OSU researchers created a new methodology that incorporates unit process modeling and an existing technique called life-cycle inventory. This allowed them to quantify a selected set of sustainability metrics, and ask real-world questions. Should the product use a different material? Would running the production line faster be worth the extra energy used or impact on worker health and safety? Which approach might lead to injuries and more lost work? How can scrap and waste be minimized? Which design alternative will generate the least greenhouse gas emissions?

To illustrate this approach in the study, the researchers used three hypothetical “bevel gear” alternatives, a common part produced in the aircraft and automotive industry. Their six-step system considered energy consumption, water use, effluent discharge, occupational health and safety, operating cost, and other factors to evaluate the use of different materials and manufacturing processes  – and ultimately concluded through mathematical modeling which of three possible designs was the most sustainable.

"When you make decisions about what is best, you may make value judgements about what aspect of sustainability is most important to you,” Haapala said. “But the modeling results have the potential to assist designers in performing those evaluations and in understanding the tradeoffs alongside other aspects of the manufacturing process.”

This work was supported by the Boeing Company and the Oregon Metals Initiative.

This assessment approach, when further researched and tested, should be applicable to a wide range of products during the design decision-making process, researchers said in the study.

Story By: 
Source: 

Karl Haapala, 541-737-3122

Multimedia Downloads
Multimedia: 

Solid steel bevel gear

Different gear types
Mechanically joined bevel gear