Developing Polymer Drugs for Cancer Treatment

Through research on drug delivery systems, Kaitlin Bratlie, assistant professor of materials science and engineering and chemical and biological engineering at Iowa State, is working on a way to treat cancers that don’t respond well to current treatments.

Her project has been underway for just a year and is several years away from clinical trials, but she says it’s the potential that keeps her motivated.

“These developments could actually turn around the prognosis of some cancer patients,” she explains.

Bratlie’s project is targeting tumor-associated macrophages, which are cells found in certain cancers and enhance the progression of tumors by creating blood vessels. She is looking to reprogram these macrophages to act instead like pro-inflammatory macrophages that prevent cancerous cells from becoming tumors.

Assisted by a team of four graduate and seven undergraduate students, she is currently developing a delivery vehicle for the drugs used to treat patients. Bratlie says other researchers have explored biodegradable polymers, but her research uses a polymer to encapsulate the medicine.

Through a grant from the National Science Foundation, Bratlie’s team is looking at a variety of chemical characteristic groups to determine their reactions with the polymer that would be used in delivering cancer-fighting medication. They want to uncover a functional group that will alter macrophage secretion profiles into pro-inflammatory macrophages

Once they have the correct functional group, the researchers plan to chemically modify a hydrogel that can encapsulate a drug within the polymer. The drug will be tested in animals, and they will look for apoptosis, or cell death, to ensure the treatment kills the cancerous cells.

Like most new developments in the world of science, Bratlie’s work with drug delivery mechanisms stems from a gap in knowledge. In this case, the gap pertains to cell responses to biomaterials. Her knowledge relating to drug release came from her post-doctoral work, which, in part, involved using biodegradable polymers to do a controlled release of corticosteroids to reduce the foreign body response to transplanted artificial organs.

“I identified a gap in the literature, and then happened to be using the drug delivery devices themselves to reprogram these macrophages,” says Bratlie. “And that’s why we’re going down this road.”

Bratlie says success with this project could offer cancer patients being treated unsuccessfully with current drug therapies a different outcome. “It would change people who have poor prognoses to actually being cured of cancer,” she adds.

March 4, 2013 by Eleni Upha

Iowa State’s MIRAGE lab mixes real and virtual to create new research opportunities

ZX6GTwo armed soldiers stand behind a barrier, guarding a checkpoint in the road, watching for trouble.A white truck turns toward them.“See what he wants, guys,” says one of the guards.“Sir, we have a military-aged male jumping out of the truck. He’s going behind that van.”

“Is he armed?”

“No visuals, sir.”

And so goes another training session in MIRAGE, an Iowa State University lab that mixes elements from virtual and real worlds to create unique training and research opportunities.  MIRAGE (Mixed Reality Adaptive Generalizable Environment) has been used by researchers since 2010. It’s part of Iowa State’s Virtual Reality Applications Center (VRAC).

The MIRAGE research team is led by Stephen Gilbert, associate director of VRAC and assistant professor ofindustrial and manufacturing systems engineering; Eliot Winer, associate director of VRAC and associate professor of mechanical engineering; and James Oliver, director of VRAC and University Professor of mechanical engineering. All three are also faculty in the human computer interaction graduate program.

The MIRAGE lab’s original project was a study for the U.S. Army Research Laboratory called “Veldt.” Gilbert said the project was designed to test whether military training that mixes physical and virtual objects could be more flexible and effective than, say, building a training facility that resembles a few city blocks of Afghanistan.

“We built MIRAGE as an ideal research lab for mixed reality,” Gilbert said. “It balances the real world with the technology we use in virtual reality.”

The lab’s technology includes:

  • a 33-foot by 11-foot screen with six projectors capable of producing 3-D images
  • 50-inch television screens that show 3-D images throughout the lab
  • 24 infrared optical tracking devices mounted in the ceiling
  • a surround-sound audio system
  • a control center loaded with computing power, graphics card technology and the capability of connecting with other virtual reality labs
  • walls, barriers and other props that can be moved around to create rooms, buildings, alleys or even a war zone checkpoint

“In this lab, we’re very good at integrating hardware from multiple systems and multiple vendors and tying it all together in novel ways,” Winer said.

In the checkpoint scenario, for example, armed guards are stationed behind barriers. The projectors show images of a road with parked cars and moving traffic. And then there’s the unidentified military-aged man jumping out of his truck and hiding behind a van.

The guards crouch behind their barrier and aim their rifles in case there’s trouble.

“It’s engaging your whole body,” Gilbert said. “It’s much more visceral.”

All movements by the soldiers-in-training – even virtual bullets from the fake rifles – are tracked to within a millimeter.

“Now we can go back and collect all this data and say, ‘The reason you made that mistake and got ‘killed’ that time was because you were looking in the wrong direction when this happened,” Oliver said in a video about the Veldt project. “We have a wealth of information we can mine to tune those training scenarios specifically to help.”

While it was originally built to study military training, MIRAGE can also help researchers with many different projects.

Gilbert is working with other researchers who are considering the MIRAGE lab for studies of violence mediation, promotion of physical fitness and the training of emergency responders. The lab has even been home to VRAC’s annual Halloween haunted house organized by students.

Gilbert said part of the lab’s effectiveness is the ability to use props and technology to create all kinds of environments. In many ways, it’s the same kind of stagecraft that goes into creating a play or movie.

“This lab,” he said, “gives you the immersive experience of the real world but the flexibility of a video game.”

“Sensing Skin” for Turbines Could Reduce the Cost of Wind Energy

A project that started out as a side experiment to monitor bridge damages has since evolved into a revolutionary, cost-saving solution in the world of wind energy.Simon Laflamme, assistant professor of civil, construction, and environmental engineering at Iowa State, began developing a damage-detecting polymer “skin” as a student at MIT.The skin, which is made into about 3-inch square pieces, consists of an inexpensive polymer material sandwiched between a painted polymer mixed with carbon black to make it conductive, which allows it to send signals to computers monitoring for any distortions.Once the skin is applied to a surface, it acts as a sensor that detects small cracks as it stretches. Its capacitance, or stored electrical charge, is measured as it changes.Originally planning to use the skin for bridges because of his background in civil engineering, Laflamme traded bridges for wind turbines when he was hired by Iowa State in 2011.

He says this shift was partly due to a lack of long-term data on the potential return on investment from monitoring the solutions when applied to bridges. With wind energy, however, researchers can determine how much money a sensing skin could save over the next 20 years.

And, he adds, the research is promising. “With wind turbines as a good application for our technology, we started some more in-depth research on the skin to find out how it behaves, its applications, and optimization,” he says. “The idea was developed before I joined Iowa State, but now our understanding and research is really taking off with the wind industry.”

Because of the damage that occurs after years of fatigue from the load of the wind, turbine blades could greatly benefit from Laflamme’s sensing skin. The blades are hollow and composed of many sheets of materials glued together that can peel and crack over time—that’s where the sensing skin comes into play.

Like biological skin, the polymer material acts like a nervous system, sensing cracks in specific areas of the turbine blade like nerves would find a cut on a finger. Once damage is detected in real time, engineers can determine whether it needs to be fixed immediately or at all, which costs less than replacing a whole blade when it is beyond repair.

After the skin is applied and damage can be detected as it occurs, a pattern can be made to assess deterioration throughout the lifetime of a turbine. “The hope is to be able to do what we call a condition assessment—to be able to predict the future of the blade,” Laflamme says. “This way, engineers could look at how the blade behaves in the past to be able to predict the probabilities of failure and damage and to optimize maintenance operation on the blade.”

Laflamme identified maintenance as a big cost issue of wind turbines. His goal is to save money in the industry by improving the maintenance schedule, which would extend the life of a typical turbine beyond the average 20 years. He says this would, in effect, reduce the cost of wind energy production.

Applying his research to turbines has allowed Laflamme to span multiple fields of engineering. The skin itself is produced in collaboration with the materials science and engineering department, but it also has ties with electrical and computer engineering for designing cost-effective data acquisition systems, and various efforts have been undertaken with aerospace engineering, the Center for Nondestructive Evaluation, and the Bridge Engineering Center at InTrans.

Laflamme says the fact that this research has a multi-disciplinary approach is a great added benefit. “This is the future of engineering—especially civil engineering—to get all fields together and create solutions for our problems,” he adds.

Iowa State Engineer looks to Dragonflies, Bats for Flight Lessons

VGKFEver since the Wright brothers, engineers have been working to develop bigger and better flying machines that maximize lift while minimizing drag.There has always been a need to efficiently carry more people and more cargo. And so the science and engineering of getting large aircraft off the ground is very well understood.But what about flight at a small scale? Say the scale of a dragonfly, a bird or a bat?Hui Hu, an Iowa State University associate professor of aerospace engineering, said there hasn’t been a need to understand the airflow, the eddies and the spinning vortices created by flapping wings and so there haven’t been many engineering studies of small-scale flight. But that’s changing.The U.S. Air Force, for example, is interested in insect-sized nano-air vehicles or bird-sized micro-air vehicles. The vehicles could fly microphones, cameras, sensors, transmitters and even tiny weapons right through a terrorist’s doorway.So how do you design a little flier that’s fast and agile as a house fly?Hu says a good place to start is nature itself.And so for a few years he’s been using wind tunnel tests and imaging technologies to learn why dragonflies and bats are such effective fliers. How, for example, do flapping frequency, flight speed and wing angle affect the lift and thrust of a flapping wing?Hu’s studies of bio-inspired aerodynamic designs began in 2008 when he spent the summer on a faculty fellowship at the Air Force Research Laboratory at Eglin Air Force Base in Florida. Over the years he’s published papers describing aerodynamic performance of different kinds of flapping wings.A study based on the dragonfly, for example, found the uneven, sawtooth surface of the insect’s wing performed better than a smooth airfoil in the slow-speed, high-drag conditions of small-scale flight. Using particle image velocimetry – an imaging technique that uses lasers and cameras to measure and record flows – Hu found the corrugated wing created tiny air cushions that kept oncoming airflow attached to the wing’s surface. That stable airflow helped boost performance in the challenging flight conditions. By describing the underlying physics of dragonfly flight, Hu and Jeffery Murphy, a former Iowa State graduate student, won a 2009 Best Paper Award in applied aerodynamics from the American Institute of Aeronautics and Astronautics.Another study of bat-like wings found the built-in flexibility of membrane-covered wings helped decrease drag and improve flight performance.And what about building tiny flying machines that use flapping wings? Can engineers come up with a reliable way to make that work?Hu has been looking into that, too.He’s using piezoelectrics, materials that bend when subjected to an electric current, to create flapping movements. That way flapping depends on feeding current to a material, rather than relying on a motor, gears and other moving parts.Hu has also used his wind tunnel and imaging tests to study how pairs of flapping wings work together – just like they do on a dragonfly. He learned wings flapping out of sync (one wing up while the second is down) created more thrust. And tandem wings working side by side, rather than top to bottom, maximize thrust and lift.Hu said these kinds of physics and aerodynamics lessons – and many more – need to be learned before engineers can design effective nano- and micro-scale vehicles.

And so he’s getting students immersed in the studies.

Hu has won a $150,000, three-year National Science Foundation grant that sends up to 12 Iowa State students to China’s Shanghai Jiao Tong University for eight weeks of intensive summer research. The students work at the university’s J.C. Wu Aerodynamics Research Center to study bio-inspired aerodynamics and engineering problems.

“We’re just now learning what makes a dragonfly work,” Hu said. “There was no need to understand flight at these small scales. But now the Defense Advanced Research Projects Agency and the Air Force say there is a need and so there’s an effort to work on it. We’re figuring out many, many interesting things we didn’t know before.”

Grad student, professor advance soil test technology invented by emeritus professor

An Iowa State University geotechnical engineering research duo has automated a soil strength test invented by an Iowa State civil engineering professor emeritus.Jeramy Ashlock, assistant professor and Black & Veatch Building a World of Difference Faculty Fellow, and geotechnical engineering Master’s graduate Ted Bechtum have automated the Borehole Shear Test (BST), an on-site soil strength test used for landslide analysis, stream-bank stability, and in early stages of building and highway construction. The BST has been used to study a diverse range of problems ranging from the impact of river bank caving on the Great Barrier Reef in Australia to major dams and other earth construction in China.Conventional direct shear testing requires bringing soil samples back from the field to test in the laboratory. The BST process is much quicker, allowing data to be collected on site. While one traditional test can take several days, the BST process can give results in one hour. By automating the BST, the efficiency and simplicity of the test is increased even further. Geotechnical engineers are able to repeat more tests in a given time than ever before. The automated BST also provides time-histories of shear stress and shear displacement. This creates possibilities for future applications, such as improving assessment of liquefaction susceptibility of soils during earthquakes.To automate the BST, Ashlock and Bechtum added a stepper motor, a stepper controller, electronic pressure sensors, an electro-pneumatic pressure regulator, and created a software control program.Bechtum, under the guidance of Ashlock, started the project to automate the BST in summer 2010. That spring he had just taken CE 360 (Geotechnical Engineering), where he discovered his love for geotechnical engineering. “Soil properties are open for interpretation, which I find intriguing,” Bechtum said. “I also found the BST project very practical and ready for future use in the field.”Bechtum defended his thesis on the Automated BST (ABST) in November. He earned his BS in civil engineering from Iowa State in December 2011 and will earn his MS in civil engineering this December as part of the concurrent BS/MS program offered at Iowa State.Anson Marston Distinguished Professor Emeritus Richard Handy (PhDCE’56) and his company, Handy Geotechnical Instruments, worked with Ashlock and Bechtum to automate the test he invented in the 1960’s. Handy taught geotechnical engineering at Iowa State from 1956-91.Ashlock and Bechtum licensed the ABST control program through the Iowa State University Research Foundation. Sales of the automated program they developed grant royalties to the research duo.In January 2013 Bechtum became a geotechnical engineer for Burns & McDonnell in Kansas City.

ECPE Researcher Completes Lab on a Chip Device

Liang Dong recently completed research on a device that can help scientists find more effective ways to protect crops and combat Parkinson’s disease by studying, of all things, worms.Nematodes possess simple nervous systems, but still share important characteristics with the nervous systems of humans. By studying nematode nerves, researchers can learn more about the human nervous system and how diseases such as Parkinson ’s disease affect it. In addition, learning more about the nematode nervous system allows researchers to devise more advanced pesticides to fight pathogens.Over the last eighteen months, Dong, assistant professor in the Iowa State University Department of Electrical and Computer Engineering , has worked with Richard J. Martin, professor of biomedical sciences in the College of Veterinary Medicine, and ECpE graduate students Peng Liu and Depeng Mao, to develop a device that can detect the muscular force of nematodes. The finished device, a “lab on a chip”, can detect such force with greater accuracy, efficiency, and cost-effectiveness than existing methods. Dong’s research was supported by the National Science Foundation and the McGee-Wagner Research Fund.“The device is small, cost-effective, accurate, and disposable,” Dong said. “I can see a lot of people who will be interested in that.”The device measures only about .25 square inches and features many tiny, micro fabricated channels. It uses two optical fibers; one single-mode fiber and one multimode fiber. The single mode fiber allows researchers to send a light into the fiber. The multimode fiber then detects the intensity of that light when a worm navigates through the channels. The device itself measures the change in the single-mode fiber’s light intensity; the greater the light intensity, the greater the actual muscle force generated. The device uses multiple detection points, which ensure far greater accuracy by averaging the recorded data from each point.With such a complex function to explore, why use nematodes for these kinds of experiments? For one, they’re inexpensive, and can be purchased hundreds at a time for a few dollars. Their one-millimeter size also makes them easy to handle in a laboratory, not to mention the tiny lab on a chip.According to Dong, 35-percent of the genes in a Caenorhabditis elegans (or C. elegans) nematode are similar to the genes of human beings. Nematode samples are simple, easy to study, and still retain enough similarity to humans to have practical applications. The researchers used a different type of nematode than the C. elegans in the experiment, but the technology the group developed can be adapted to measure the C. elegans without modification.The research, which was featured in Vertical NEWS and published in Lab on a Chip as “An integrated fiber-optic microfluidic device for detection of muscular force generation of microscopic nematodes”, has an impact that goes far beyond nematodes. Dong’s research on nematode systems can be adapted for use on human nervous systems, and can help provide valuable data on conditions like Parkinson’s disease.“A sensor for nematodes will help biologists studying the nervous system towards finding a way to help patients with Parkinson’s,” Dong said.Further, measuring muscular force can show how resistant the worms are to specific chemical combinations. Researchers can use data collected from Dong’s lab on a chip to devise chemical combinations for which nematodes and other pathogens have no resistance. This could lead to breakthroughs in the science of crop protection and provide farmers with more advanced pesticides that kill pests but preserve the environment.“There are many kinds of parasites and pathogens out there, and most of them have developed some level of resistance,” Dong said. “A critical issue is how to kill parasites and pathogens while protecting the environment. You want to accurately measure their drug resistance to find the proper methods to deal with them.”The next step in Dong’s research is to find opportunities in the biomechanics industry to develop an official prototype device that can then be commercialized. Dong is confident that companies and organizations will see the benefits of his design.

October 25, 2012 by Thane Himes

Professor Invents Sewer Pipe Made of Recycled Plastic, Fly Ash

Pipe-and-materials_David-White-patentDavid White, the Richard L. Handy Endowed Associate Professor in geotechnical/materials engineering, has invented a sewer pipe made of recycled plastic soda bottles, plastic fibers and fly ash.“America’s infrastructure currently has about 600,000 miles of sewer pipes, much of which is older than 30 years and in need of repair,” White says. “I feel that we must find a pipe made of more sustainable, sewage-resistant materials to accommodate our sanitary needs.” Sulfuric acid, commonly found in sewage, is slowly disintegrating the current concrete sewer pipes in municipalities throughout the U.S.White’s patented solution combines recycled, post-consumer waste polyethylene terephthalate (typical soda bottle plastic), fly ash (coal remains after use in power plant), and plastic fiber reinforcement. This sewer pipe invention is lighter and stronger than conventional sewer pipe made of Portland cement concrete. White’s solution also has higher structural capacity, is more resistant to acid and is less dense.  The new pipe material is more environmentally friendly, too, which White is especially proud of. “By using recycled soda bottle plastic, significantly less crude oil is used than using petroleum-based virgin plastic.” To test his invention, White gathered 99 percent of the materials locally. Plastic soda bottles came from Iowa State campus bottle collections; fly ash came from burnt coal at the Ames Municipal Power Plant; and plastic fibers (1 percent) were ordered from a supply company.The research work conducted by White has demonstrated that technology is feasible for making laboratory-scale pipe sections 12 inches in diameter.  The next stage in the development process will be full-scale production trials, for which White seeks industry partners with interest in commercializing the technology.White received a U.S. patent for this “Polymer mortar composite pipe material and manufacturing method” on October 25, 2011.

October 17, 2012 by Chris Neary

Evolving Microbes Help Iowa State Engineers Turn Bio-Oil into Advanced Bio-Fuels

Microbes are working away in an Iowa State University laboratory to ferment biofuels from the sugar and acetate produced by rapidly heating biomass such as corn stalks and sawdust.

But it’s not an easy job for E. coli and C. reinhardtii.

The bacteria and microalgae, respectively, don’t like something in the bio-oil produced by fast pyrolysis – the rapid heating of biomass without oxygen and with catalysts. The result of the thermochemical process is a thick, brown oil that smells like molasses.

A research team led by Laura Jarboe, an Iowa State assistant professor of chemical and biological engineering, is feeding the bio-oil (also known as “pyrolytic sugars”) to the microbes. The E. coli are supposed to turn the levoglucosan in the sugar-rich fraction of bio-oil into ethanol and lactic acid; the C. reinhardtii are supposed to turn acetate-rich fractions into lipids for biodiesel.

It’s part of the hybrid approach Iowa State researchers are using to produce the next generation of biofuels. They’re combining two conversion paths – thermochemical and biochemical – to find efficient ways to produce renewable fuels and chemicals.

“The goal is to produce biorenewable fuels and chemicals in a manner that’s economically competitive with petroleum-based processes,” Jarboe said.

There are, however, contaminants and toxins in the bio-oil that are getting in the way of the fuel production. Jarboe and a research team are experimenting with pre-treatments of the bio-oil that could reduce the toxicity. And they’re working to develop microbes that can tolerate the contaminants.

In addition to Jarboe, the research team includes Robert C. Brown, the Iowa Farm Bureau Director of Iowa State’s Bioeconomy Institute, an Anson Marston Distinguished Professor in Engineering and the Gary and Donna Hoover Chair in Mechanical Engineering; Zhiyou Wen, an associate professor of food science and human nutrition; Zhanyou Chi, a post-doctoral research associate for Iowa State’s Center for Sustainable Environmental Technologies; Tao Jin, a doctoral student in chemical and biological engineering; and Yi Liang, a doctoral student in food science and human nutrition. The project is supported by a three-year, $300,000 grant from the National Science Foundation and a three-year, $315,020 grant from the Iowa Energy Center.

The researchers are using a technique called directed evolution to produce microbes that are more tolerant of the contaminants in bio-oil. The microbes are grown with higher and higher concentrations of bio-oil and as they divide, they replicate their DNA. Sometimes there are replication mistakes that lead to mutations.

“It could be a mistake that’s immediately lethal,” Jarboe said. “Or it could be a mistake that helps the microbe tolerate the problematic compounds and it grows faster.

“At the end of the process, we want to say, ‘Hey, I’ve got a great bug.’”

Every day researchers check the experiments for signs of progress. So far, Jarboe said the evolving bacteria and microalgae have been able to tolerate slightly higher concentrations of bio-oil.

When mutations eventually produce a better breed of microbe, the researchers will analyze genomic data to learn and understand the important mutations. That will allow researchers to duplicate the microbes for better biofuel production.

Jarboe said development of those hungry, robust microbes could lead to important advancements in biofuel production: a hybrid process that’s biorenewable, fast, cheap and doesn’t depend on food crops as a source of biomass.

October 12, 2012 by Mike Krapfl

Quantifying Cascading Power Failure

Around 2 p.m. on August 14, 2003, an overhead transmission line carrying 345 kilovolts of electricity near Walton Hills, Ohio sagged too close to a nearby tree and shorted out. By 4 p.m., more than 50 million people were affected by one of the largest blackouts in history.In September 2011, an Arizona Public Works employee, performing a routine procedure at the North Gila substation near Yuma, tripped off a 500-kilovolt line and began a series of failures that left more than 2 million people without power in the Southwest United States.Both trigger events were small, seemingly inconsequential incidents. Both resulted in massive power outages by setting off an effect called cascading failure, a topic of considerable study for Ian Dobson, Arend J. and Verna V. Sandbulte Professor in Engineering.“What happens is, a failure occurs somewhere and weakens the system a bit,” Dobson says. “On a bad day, something else happens. Usually it doesn’t, but on that day, let’s say, it does. If it’s a really bad day, then a third thing happens and the system becomes degraded. You’re in a situation where it’s more likely that the next failure is going to happen because the last failure already happened. That’s the idea of cascading failure.”The failure of the Walton Hills line, a relatively minor occurrence given the size and scale of the power grid, reverberated through the network and helped cause a series of events that brought down a sizable chunk of the nation’s power infrastructure. The initial point of failure in Ohio shifted the power burden to other points down the line and made a malfunction in these points much more likely – a classic case of cascading failure.“What we’re talking about is the big power grid that stretches from here to Florida and Maine and Canada – everything east of the Rockies is all connected together, all humming together,” Dobson says. “Everything in the power system is protected so it doesn’t fry when something goes wrong. Things can disconnect to protect the equipment, but if you disconnect enough things, you get a blackout.”Those disconnects are usually the very thing keeping the grid from destroying itself during a large-scale cascading event. Failures in the grid are rare and typically unanticipated because, as Dobson says, everything that can be anticipated has usually already been integrated into the grid.“Something trips out the line and the power system wobbles a little bit,” Dobson says. “Under normal operation you’ve already designed for normal faults. With anything that commonly goes wrong with the system, engineers and everyone in the utility industry rushes around and makes sure that it doesn’t happen again. Most common, understandable, or easy to figure out things are already mitigated. Unusual stuff – rare interactions, unusual combinations of things when the system is already degraded – is a lot harder to control.”Dobson’s research goes beyond what can be anticipated and attempts to figure out the overall likelihood of large-scale blackouts, like the events in 2003 and 2011, by studying the interactions between various points in the system using a series of math equations and simulations. In effect, Dobson is using models to simulate the “perfect storm” in the power grid, though he disputes the terminology.“People always say ‘It was the perfect storm.’” Dobson says. “But these large blackouts happen because of the cascading effect. You’re never going to get 20 different independent failures to happen at the same time because that’s vanishingly unlikely. But if the first couple events make the next events more likely, then those events happen and make the next ones more likely – then you get those rare events happening. This is the typical way that large complicated systems have catastrophic failures, and it is not really a perfect storm.”Cascading failure is difficult to analyze because of the huge number of unanticipated variables. In other words, researchers don’t know what they don’t know. In addition, the dependence of individual failures on previous failures and their effect on subsequent failures creates an incredibly complex system of dependent variables. Large blackouts involve the failure of many interconnected variables, each of which affect how variables down the line interact with each other.“Imagine you’re very, very tightly scheduled on a certain day,” Dobson says. “Then, things start getting delayed in the morning and things get worse and worse throughout the day. Because your first appointment was delayed, It’s more likely that the next one will be delayed. Pretty soon you start missing appointments altogether in the afternoon. That’s a very small example of cascading failure.”There are a few common attributes, like critical loading, that researchers can look for when studying cases of cascading failure. A power grid’s critical loading can be defined as a point somewhere between a very low load and a very high load where the risk of a blackout increases sharply. If the amount of electricity flowing through the system is higher than the power grid critical load, the likelihood of a blackout spikes. The power grid’s critical load acts as a reference point for cascading failure; stay below it and the system will likely be fine. Go above it, and the risk of a blackout is more severe.

“If a transmission line carrying its usual load fails, other lines can pick up the slack without much trouble,” he says. “But if the power grid as a whole is carrying a load that is above its critical loading, its burden has a much greater effect on the other lines. That’s something we look for.”

Dobson uses a number of models and power system simulations of cascading failure to develop risk analysis methods for the power grid. Much like businesses use risk analysis procedures to identify and assess potential shortcomings within a project or account, Dobson uses his models to quantify the size and cost of a blackout given data on the power grid and its internal interactions. His findings can eventually be used to recommend upgrades in the power grid and determine the value and necessity of those upgrades.

“There’s a difference between recommending power grid upgrades and recommending prudent and cost-effective power grid upgrades,” Dobson says. “We have to figure out the best places to upgrade and focus resources there.”

August 17, 2012 by Brock Ascher

Iowa State Engineer Discovers Spider Silk Conducts Heat as well as Metals

Xinwei Wang, Guoqing Liu and Xiaopeng Huang, left to right, show the instruments they used to study the thermal conductivity of spider silk
Xinwei Wang, Guoqing Liu and Xiaopeng Huang, left to right, show the instruments they used to study the thermal conductivity of spider silk

Xinwei Wang had a hunch that spider webs were worth a much closer look.

So he ordered eight spiders – Nephila clavipes, golden silk orbweavers – and put them to work eating crickets and spinning webs in the cages he set up in an Iowa State University greenhouse.

Wang, an associate professor of mechanical engineering at Iowa State, studies thermal conductivity, the ability of materials to conduct heat. He’s been looking for organic materials that can effectively transfer heat. It’s something diamonds, copper and aluminum are very good at; most materials from living things aren’t very good at all.

But spider silk has some interesting properties: it’s very strong, very stretchy, only 4 microns thick (human hair is about 60 microns) and, according to some speculation, could be a good conductor of heat. But nobody had actually tested spider silk for its thermal conductivity.

And so Wang, with partial support from the Army Research Office and the National Science Foundation, decided to try some lab experiments. Xiaopeng Huang, a post-doctoral research associate in mechanical engineering; and Guoqing Liu, a doctoral student in mechanical engineering, helped with the project.

“I think we tried the right material,” Wang said of the results.

What Wang and his research team found was that spider silks – particularly the draglines that anchor webs in place – conduct heat better than most materials, including very good conductors such as silicon, aluminum and pure iron. Spider silk also conducts heat 1,000 times better than woven silkworm silk and 800 times better than other organic tissues.

A paper about the discovery – “New Secrets of Spider Silk: Exceptionally High Thermal Conductivity and its Abnormal Change under Stretching” – has just been published online by the journal Advanced Materials.

“Our discoveries will revolutionize the conventional thought on the low thermal conductivity of biological materials,” Wang wrote in the paper.

The paper reports that using laboratory techniques developed by Wang – “this takes time and patience” – spider silk conducts heat at the rate of 416 watts per meter Kelvin. Copper measures 401. And skin tissues measure .6.

“This is very surprising because spider silk is organic material,” Wang said. “For organic material, this is the highest ever. There are only a few materials higher – silver and diamond.”

Even more surprising, he said, is when spider silk is stretched, thermal conductivity also goes up. Wang said stretching spider silk to its 20 percent limit also increases conductivity by 20 percent. Most materials lose thermal conductivity when they’re stretched.

That discovery “opens a door for soft materials to be another option for thermal conductivity tuning,” Wang wrote in the paper.

And that could lead to spider silk helping to create flexible, heat-dissipating parts for electronics, better clothes for hot weather, bandages that don’t trap heat and many other everyday applications.

What is it about spider silk that gives it these unusual heat-carrying properties?

Wang said it’s all about the defect-free molecular structure of spider silk, including proteins that contain nanocrystals and the spring-shaped structures connecting the proteins. He said more research needs to be done to fully understand spider silk’s heat-conducting abilities.

Wang is also wondering if spider silk can be modified in ways that enhance its thermal conductivity. He said the researchers’ preliminary results are very promising.

And then Wang marveled at what he’s learning about spider webs, everything from spider care to web unraveling techniques to the different silks within a single web. All that has one colleague calling him Iowa State’s Spiderman.

“I’ve been doing thermal transport for many years,” Wang said. “This is the most exciting thing, what I’m doing right now.”

March 5, 2012 by Mike Krapfl

ISU Professor takes on Threat of Espionage via Hacked Smartphones

It’s not exactly dinner-table conversation, but cyber insecurity is bearing down on everyone from company CEOs to generals at U.S. military bases overseas.Recent incidents, particularly the hacking of government websites by the group Anonymous and the theft of confidential data from online retailers like Zappos, have raised questions about Internet safety. Congress’ recent introduction of the Stop Online Piracy Act exposed how complex the issue has become.In an age where most American businesses are reliant on computers to help run their day-to-day operations, and citizens habitually keep their tablets or smart phones within reach, the task of locking out cyber threats has become increasingly difficult.Suraj Kothari, a professor of electrical and computer engineering, is researching how to ward off cyber infiltration. His newest endeavor, a $4.1 million project to develop security software for Android-powered smart phones, could potentially affect every American with a hand-held mobile device.“We hear about cyber security,” Kothari said, “For example, a computer can be attacked, and you will see things on your disk are wiped out so you know something bad has happened. Now, there are new types of attacks that are going to happen or maybe are happening now. Your cell phone has been compromised, but you don’t even know it has been compromised.”In conjunction with Iowa-based EnSoft Corp., a software management company, Kothari is developing a tool to analyze potentially malicious software on Android phones.His research, funded through the Defense Advanced Research Projects Agency (DARPA), will focus on software applications commonly used by members of the U.S. military who carry smart phones.• • •Since the incident in 2005 when Paris Hilton’s cell phone was hacked and explicit photos were leaked onto the Internet, the ease of hacking into personal devices has become ordinary for some and frightening for others.In the case of military phones, keeping sensitive information out of the wrong hands could be key to American national security.

“Let’s say a general is talking to somebody else and that conversation is being leaked through the phone because the phone is interacting with the outside world … but somebody has now sneaked in software which is taking sensitive information and leaking it out to other sources,” Kothari said. “And the person who is using the phone doesn’t even know that’s what’s happening. That would be a very serious problem.”

Jeremías Sauceda, a co-principal researcher, said there haven’t been any major hacking incidents on military phones. But, he said, funding research in this area will hopefully help prevent dangerous episodes in the future.

“It’s not that some incident has happened and they are responding,” Sauceda said. “They are being proactive. Now they want to equip their personnel with smart phones. In the process of adopting that technology, they need to make sure it’s secure.”

Sauceda is a researcher for EnSoft Corp., a company located at ISU’s Research Park. Using Kothari’s innovations, Sauceda will develop a product that can be installed on military phones by the end of the 3 1/2-year project.

The idea isn’t simple, but it also isn’t new.

The project, which officially kicks off Feb. 22, will use techniques Kothari has been developing over a 15-year professional career in software analysis.

“Forty or 50 years ago, if somebody went to a doctor, the doctor would say, ‘OK, what are your symptoms?’ … The doctor is observing what’s going on in your body from the outside,” he said. “Testing is like that.”

Kothari’s analysis, however, looks at the software from the inside out, making his technique more like a modern doctor’s MRI machine.

“This is a very different way of analyzing and understanding software,” Kothari said, “and one application of it is to improve reliability.”

Downloadable mobile apps, which are often updated by their developer to improve usability, pose a tricky problem for software analysts who only rely on testing-based methods. Kothari said his goal is to develop a tool capable of probing a downloaded app and understanding its content, even after multiple updates or changes are made to the program.

February 13, 2012 by Hannah Furfaro