Nano research could impact flexible electronic devices

ScienceDaily (Jan. 12, 2012) — A discovery by a research team at North Dakota State University, Fargo, and the National Institute of Standards and Technology (NIST), shows that the flexibility and durability of carbon nanotube films and coatings are intimately linked to their electronic properties. The research could one day impact flexible electronic devices such as solar cells and wearable sensors. The research also provided a promising young high school student the chance to work in the lab with world-class scientists, jumpstarting her potential scientific career.

The NDSU/NIST research team, led by Erik Hobbie, Ph.D., is working to determine why thin films made from metallic single-wall carbon nanotubes are superior for potential applications that demand both electronic performance and mechanical durability. "One simple reason is that the metallic nanotubes tend to transport charge more easily when they touch each other," said Hobbie. "But another less obvious reason has to do with how much the films can flex without changing their structure at very small scales."

Results from the study are published in ACS Nano.

The team includes NDSU graduate student John M. Harris; postdoctoral researcher Ganjigunte R. Swathi Iyer; Anna K. Bernhardt, North Dakota Governor's School attendee; and NIST researchers Ji Yeon Huh, Steven D. Hudson and Jeffrey A. Fagan.

There is great interest in using carbon nanotube films and coatings as flexible transparent electrodes in electronic devices such as solar cells. "Our research demonstrates that the flexibility and durability of these films are intimately linked to their electronic properties," said Hobbie. "This is a very new idea, so hopefully, it will generate a new series of studies and questions focused on the exact origins and consequences of this effect."

Such research could potentially result in material that reduces solar cell costs, and leads to the ability to use them in clothing or foldable electronics. Electronic devices currently on the market that require transparent electrodes, like touch screens and solar cells, typically use indium tin oxide, an increasingly expensive material. "It is also very brittle," said Hobbie, "implying that it cannot be used in devices that require mechanical flexibility like wearable or foldable electronics."

Single-wall carbon nanotubes show significant promise as transparent conductive coatings with outstanding electronic, mechanical and optical properties. "A particularly attractive feature of these films is that the physical properties can be tuned through the addition or subtraction of a relatively small number of nanotubes," said Hobbie. "Thin films made from such materials hold tremendous potential for flexible electronics applications, including the replacement of indium tin oxide in liquid crystal displays and photovoltaic devices."

Thin films made from metallic single-wall carbon nanotubes show better durability as flexible transparent conductive coatings, which the researchers attribute to a combination of superior mechanical performance and higher interfacial conductivity. The research team found significant differences in the electronic manifestations of thin-film wrinkling, depending on the electronic type of the nanotubes, and examined the underlying mechanisms.

The results of this study suggest that the metallic films make better flexible transparent conductive coatings; they have higher conductivity and are more durable. "Our results are relevant to a number of ongoing efforts in transparent conducting films and flexible electronic devices," said Hobbie.

The research was supported by the National Science Foundation through CMMI-0969155 and the U.S. Department of Energy through DE-FB36-08GO88160.

The opportunity to work on such research was new to Anna Bernhardt, a high school junior from a town of 1,000 people in western North Dakota. She was among 66 of the most academically driven high school sophomores and juniors who attended a six-week intensive summer residential program on the NDSU campus for scholastically motivated students in the state.

Students receive concentrated instruction from 40 NDSU faculty through discussion groups, labs, field trips and other activities. The state of North Dakota funds the cost of participation for North Dakota students who are accepted into the program. It's available free to public school students, while private and homeschool students selected for the program can make arrangements to attend for free through their local public school district.

While it is unusual for a young student to be involved in nanotechnology research at this level, it presented an opportunity for everyone involved. Bernhardt prepared single-wall carbon nanotube samples and participated in testing of the samples. "The experience of working in a research setting has helped me to decide that I would love to do more research in the future," said the young scientist. "The biggest benefit of working in the lab was getting a taste of the true research experience. Without North Dakota's Governor's School, I would never have been able to have this experience and surely wouldn't be so certain that I would like to do more research in the future."

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The above story is reprinted from materials provided by North Dakota State University, via Newswise.

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Journal Reference:

John M. Harris, Ganjigunte R. Swathi Iyer, Anna K. Bernhardt, Ji Yeon Huh, Steven D. Hudson, Jeffrey A. Fagan, Erik K. Hobbie. Electronic Durability of Flexible Transparent Films from Type-Specific Single-Wall Carbon Nanotubes. ACS Nano, 2011; 111220100417004 DOI: 10.1021/nn204383t

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Early research on cellphone conversations likely overestimated crash risk, study suggests

ScienceDaily (Dec. 14, 2011) — A Wayne State University study published in the January 2012 issue of the journal Epidemiology points out that two influential early studies of cellphone use and crash risk may have overestimated the relative risk of conversation on cellphones while driving.

In this new study, Richard Young, Ph.D., professor of research in Wayne State University's Department of Psychiatry and Behavioral Neurosciences in the School of Medicine, examined possible bias in a 1997 Canadian study and a 2005 Australian study. These earlier studies used cellphone billing records of people who had been in a crash and compared their cellphone use just before the crash to the same time period the day (or week) before -- the control window.

Young said the issue with these studies is that people may not have been driving during the entire control window period, as assumed by the earlier study investigators.

"Earlier case-crossover studies likely overestimated the relative risk for cellphone conversations while driving by implicitly assuming that driving during a control window was full time when it may have been only part time," said Young. "This false assumption makes it seem like cellphone conversation is a bigger crash risk than it really is."

In Young's new study, his research team used Global Positioning Satellite (GPS) data to track day-to-day driving of more than 400 drivers during a 100-day period. He then divided the days into pairs, with the first day representing the "control" day and the second day representing the "crash" day in the earlier studies. Overall, the team found little driving consistency in any given clock time period between the two days -- driving time on the control day was only about one-fourth of the driving time on the crash day, during any specific clock time period.

"This underestimation of the amount of driving in the control windows by nearly four times could reduce cellphone conversation time in that control period," Young said. "It makes it appear that there is less cellphone conversation in control periods than in the time just before a crash, making the relative risk estimate appear greater than it really is."

Young found that when the cellphone conversation time in the control window was adjusted for the amount of driving, the amount of cellphone usage in the control window was about the same as in the minutes before a crash. He concluded that the crash risk for cellphone conversation while driving is one-fourth of what was claimed in previous studies, or near that of normal baseline driving.

Young added that many well-controlled studies with real driving show that the primary increase in crash risk from portable electronic devices comes from tasks that require drivers to look at the device or operate it with their hands, such as texting while driving. Five other recent real-world studies concur with his conclusion that the crash risk from cellular conversations is not greater than that of driving with no conversation.

"Tasks that take a driver's eyes off the road or hands off the steering wheel are what increase crash risk," said Young. "Texting, emailing, manual dialing and so forth -- not conversation -- are what increase the risk of crashes while driving."

The National Transportation Safety Board has recommended that all 50 states and the District of Columbia ban the non-emergency use of portable electronic devices for all drivers. Young said this recommendation goes beyond the data from newer studies, including his, because it would ban cellphone conversations while driving.

"Recent real-world studies show that cellphone conversations do not increase crash risk beyond that of normal driving -- it is the visual-manual tasks that take the eyes off the road and the hands off the wheel that are the real risk," said Young.

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Journal Reference:

Richard A. Young. Cell Phone Use and Crash Risk. Epidemiology, 2012; 23 (1): 116 DOI: 10.1097/EDE.0b013e31823b5efc

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Video game playing tied to creativity, research shows

ScienceDaily (Nov. 2, 2011) — Both boys and girls who play video games tend to be more creative, regardless of whether the games are violent or nonviolent, according to new research by Michigan State University scholars.

A study of nearly 500 12-year-olds found that the more kids played video games, the more creative they were in tasks such as drawing pictures and writing stories. In contrast, use of cell phones, the Internet and computers (other than for video games) was unrelated to creativity, the study found.

Linda Jackson, professor of psychology and lead researcher on the project, said the study appears to be the first evidence-based demonstration of a relationship between technology use and creativity. About 72 percent of U.S. households play video or computer games, according to the Entertainment Software Association.

The MSU findings should motivate game designers to identify the aspects of video game activity that are responsible for the creative effects, Jackson said.

"Once they do that, video games can be designed to optimize the development of creativity while retaining their entertainment values such that a new generation of video games will blur the distinction between education and entertainment," Jackson said.

The researchers surveyed 491 middle-school students as part of MSU's Children and Technology Project, which is funded by the National Science Foundation. The survey assessed how often the students used different forms of technology and gauged their creativity with the widely used Torrance Test of Creativity-Figural.

The Torrance test involved tasks such as drawing an "interesting and exciting" picture from a curved shape, giving the picture a title and then writing a story about it.

In addition, the study found that boys played video games more than girls, and that boys favored games of violence and sports while girls favored games involving interaction with others (human or nonhuman).

Yet, regardless of gender, race or type of game played by the students, the study found a relation between video game playing and greater creativity.

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Linda A. Jackson, Edward A. Witt, Alexander Ivan Games, Hiram E. Fitzgerald, Alexander von Eye, Yong Zhao. Information technology use and creativity: Findings from the Children and Technology. Computers in Human Behavior, 2011 DOI: 10.1016/j.chb.2011.10.006

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Arctic research funding of $67M finally announced

The federal government formally announced $67.3 million for research on Arctic climate change Thursday, though the funding has already been flowing for months and an official website has long since divulged it.

Industry Minister Christian Paradis said the money would keep ArcticNet, a Canada-wide network of mostly university-based researchers, operating through 2018.

The 145 investigators run projects looking at topics as diverse as Inuit access to post-secondary education, to how global warming is affecting marine life on the floor of the Arctic Ocean.

ArcticNet's first round of funding came in 2003, and researchers have known it would be renewed since last fall, when the federal government quietly extended its financial commitment.

The exact amount of the second round of funding was later posted to the federal government's website for the Networks of Centres of Excellence, which supports national research collaborations.

But there was still no formal announcement from the government. The Prime Minister's Office said in August that Natural Resources Minister Joe Oliver would make the official announcement in the fall, even as Industry Canada was already at work planning something for that month.

"It's a matter of opportunity," said Louis Fortier, a Laval University marine biologist and ArcticNet's scientific director. "We agreed with the Industry Department that we wanted to do the announcement in the North, and in the wintertime it's impossible, so the first favourable window was in August. We had something planned for the beginning of August in Resolute Bay, but things are always complicated in the North, and this is just one more example."

In the end, Paradis made the announcement Thursday alongside Fortier at Laval University in Quebec City, where he said the funding was the single largest amount Ottawa has doled out as part of the Networks of Centres of Excellence program.

All the machinations haven't been detrimental to ArcticNet's researchers, however, several of them said.

"The research community knew, when we had our last annual scientific meeting in December, that the decision had been made," said David Hik, a University of Alberta biologist and ArcticNet project leader.

"The fact the official announcement was delayed isn't a big deal. It hasn't delayed the flow of the funds, and none of the investigators would have been adversely affected at all. Probably with the election in May, a lot of these timelines got set back."

Fortier agreed there has been no adverse effect. "This is something the 145 of them were expecting. We were confident we would get funding," he said.

He added that the federal contribution is only a part of ArcticNet's budget. The government cash has a "leveraging effect" that allows the program to raise further funds from universities, granting agencies and elsewhere, for a total over the next seven years of between $400 million and $500 million, he said.

About $2.7 million a year of that goes toward operating the Canadian Coast Guard ship Amundsen, a 98-metre-long icebreaker that Arctic researchers use every May to December to travel to the remote North to study Inuit communities and the environment. Accessibility Links

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