Tag Archives: Penn State

Cellulose- and chitin-based biomaterial to replace plastics?

Although the term is not actually used in the news release, one of the materials used to create a new biomaterial could safely be described as nanocellulose. From a Sept. 20, 2017 Pennsylvania State University (Penn State) news release (also on EurekAlert) by Jeff Mulhollem,

An inexpensive biomaterial that can be used to sustainably replace plastic barrier coatings in packaging and many other applications has been developed by Penn State researchers, who predict its adoption would greatly reduce pollution.

Completely compostable, the material — a polysaccharide polyelectrolyte complex — is comprised of nearly equal parts of treated cellulose pulp from wood or cotton, and chitosan, which is derived from chitin — the primary ingredient in the exoskeletons of arthropods and crustaceans. The main source of chitin is the mountains of leftover shells from lobsters, crabs and shrimp consumed by humans.

These environmentally friendly barrier coatings have numerous applications ranging from water-resistant paper, to coatings for ceiling tiles and wallboard, to food coatings to seal in freshness, according to lead researcher Jeffrey Catchmark, professor of agricultural and biological engineering, College of Agricultural Sciences.

“The material’s unexpected strong, insoluble adhesive properties are useful for packaging as well as other applications, such as better performing, fully natural wood-fiber composites for construction and even flooring,” he said. “And the technology has the potential to be incorporated into foods to reduce fat uptake during frying and maintain crispness. Since the coating is essentially fiber-based, it is a means of adding fiber to diets.”

The amazingly sturdy and durable bond between carboxymethyl cellulose and chitosan is the key, he explained. The two very inexpensive polysaccharides — already used in the food industry and in other industrial sectors — have different molecular charges and lock together in a complex that provides the foundation for impervious films, coatings, adhesives and more.

The potential reduction of pollution is immense if these barrier coatings replace millions of tons of petroleum-based plastic associated with food packaging used every year in the United States — and much more globally, Catchmark noted.

He pointed out that the global production of plastic is approaching 300 million tons per year. In a recent year, more than 29 million tons of plastic became municipal solid waste in the U.S. and almost half was plastic packaging. It is anticipated that 10 percent of all plastic produced globally will become ocean debris, representing a significant ecological and human health threat.

crab shells

The material is comprised of cellulose pulp from wood or cotton, and chitosan, derived from chitin, the primary ingredient in the exoskeletons of arthropods and crustaceans. The main source of chitin is shells from lobsters, crabs and shrimp. Image: © iStock Photo OKRAD

The polysaccharide polyelectrolyte complex coatings performed well in research, the findings of which were published recently in Green Chemistry. Paperboard coated with the biomaterial, comprised of nanostructured fibrous particles of carboxymethyl cellulose and chitosan, exhibited strong oil and water barrier properties. The coating also resisted toluene, heptane and salt solutions and exhibited improved wet and dry mechanical and water vapor barrier properties.

“These results show that polysaccharide polyelectrolyte complex-based materials may be competitive barrier alternatives to synthetic polymers for many commercial applications,” said Catchmark, who, in concert with Penn State, has applied for a patent on the coatings.

“In addition, this work demonstrates that new, unexpected properties emerge from multi-polysaccharide systems engaged in electrostatic complexation, enabling new high-performance applications.”

Catchmark began experimenting with biomaterials that might be used instead of plastics a decade or so ago out of concerns for sustainability. He became interested in cellulose, the main component in wood, because it is the largest volume sustainable, renewable material on earth. Catchmark studied its nanostructure — how it is assembled at the nanoscale.

He believed he could develop natural materials that are more robust and improve their properties, so that they could compete with synthetic materials that are not sustainable and generate pollution — such as the low-density polyethylene laminate applied to paper board, Styrofoam and solid plastic used in cups and bottles.

“The challenge is, to do that you’ve got to be able to do it in a way that is manufacturable, and it has to be less expensive than plastic,” Catchmark explained. “Because when you make a change to something that is greener or sustainable, you really have to pay for the switch. So it has to be less expensive in order for companies to actually gain something from it. This creates a problem for sustainable materials — an inertia that has to be overcome with a lower cost.”

lab vials

The amazingly sturdy and durable bond between carboxymethyl cellulose and chitosan is the key. The two very inexpensive polysaccharides, already used in the food industry and in other industrial sectors, have different molecular charges and lock together in a complex that provides the foundation for impervious films, coatings, adhesives and more. Image: Penn State

Funded by a Research Applications for Innovation grant from the College of Agricultural Sciences, Catchmark currently is working to develop commercialization partners in different industry sectors for a wide variety of products.

“We are trying to take the last step now and make a real impact on the world, and get industry people to stop using plastics and instead use these natural materials,” he said. “So they (consumers) have a choice — after the biomaterials are used, they can be recycled, buried in the ground or composted, and they will decompose. Or they can continue to use plastics that will end up in the oceans, where they will persist for thousands of years.”

Also involved in the research were Snehasish Basu, post-doctoral scholar, and Adam Plucinski, master’s degree student, now instructor of engineering at Penn State Altoona. Staff in Penn State’s Material Research Institute provided assistance with the project.

The U.S. Department of Agriculture supported this work. Southern Champion Tray, of Chattanooga, Tennessee, provided paperboard and information on its production for experiments.

Here’s a link to and a citation for the paper,

Sustainable barrier materials based on polysaccharide polyelectrolyte complexes by
Snehasish Basu, Adam Plucinski, and Jeffrey M. Catchmark. Green Chemistry 2017, 19, 4080-4092 DOI: 10.1039/C7GC00991G

This paper is behind a paywall. One comment, I found an anomaly on the page when I visited. At the top of the citation page, it states that this is issue 17 of Green Chemistry but the citation in the column on the right is “2017, 19 … “, which would be issue 19.

Getting too hot? Strap on your personal cooling unit

Individual cooling units for firefighters, foundry workers, and others working in hot conditions are still in the future but if Pennsylvania State University (Penn State) researchers have their way that future is a lot closer than it was. From an April 29, 2016 news item on Nanotechnology Now,

Firefighters entering burning buildings, athletes competing in the broiling sun and workers in foundries may eventually be able to carry their own, lightweight cooling units with them, thanks to a nanowire array that cools, according to Penn State materials researchers.

An April 28, 2016 Penn State news release by A’ndrea Elyse Messer, which originated the news item, describes some of the concepts and details some of the technology,

“Most electrocaloric ceramic materials contain lead,” said Qing Wang, professor of materials science and engineering. “We try not to use lead. Conventional cooling systems use coolants that can be environmentally problematic as well. Our nanowire array can cool without these problems.”

Electrocaloric materials are nanostructured materials that show a reversible temperature change under an applied electric field. Previously available electrocaloric materials were single crystals, bulk ceramics or ceramic thin films that could cool, but are limited because they are rigid, fragile and have poor processability. Ferroelectric polymers also can cool, but the electric field needed to induce cooling is above the safety limit for humans.

Wang and his team looked at creating a nanowire material that was flexible, easily manufactured and environmentally friendly and could cool with an electric field safe for human use. Such a material might one day be incorporated into firefighting gear, athletic uniforms or other wearables. …

Their vertically aligned ferroelectric barium strontium titanate nanowire array can cool about 5.5 degrees Fahrenheit using 36 volts, an electric field level safe for humans. A 500 gram battery pack about the size of an IPad could power the material for about two hours.

The researchers grow the material in two stages. First, titanium dioxide nanowires are grown on fluorine doped tin oxide coated glass. The researchers use a template so all the nanowires grow perpendicular to the glass’ surface and to the same height. Then the researchers infuse barium and strontium ions into the titanium dioxide nanowires.

The researchers apply a nanosheet of silver to the array to serve as an electrode.

They can move this nanowire forest from the glass substrate to any substrate they want — including clothing fabric — using a sticky tape.

“This low voltage is good enough for modest exercise and the material is flexible,” said Wang. “Now we need to design a system that can cool a person and remove the heat generated in cooling from the immediate area.”

This solid state personal cooling system may one day become the norm because it does not require regeneration of coolants with ozone depletion and global warming potentials and could be lightweight and flexible.

Here’s a link to and a citation for the paper,

Toward Wearable Cooling Devices: Highly Flexible Electrocaloric Ba0.67Sr0.33TiO3 Nanowire Arrays by Guangzu Zhang, Xiaoshan Zhang, Houbing Huang, Jianjun Wang, Qi Li, Long-Qing Chen, and Qing Wang. Advanced Materials DOI: 10.1002/adma.201506118 Article first published online: 27 APR 2016

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

One final comment, I’m trying to imagine a sport where an athlete would willingly wear any material that adds weight. Isn’t an athlete’s objective is to have lightweight clothing and footwear so nothing impedes performance?

Is the medium the message? Virtual museums and the the user’s experience technology experience

A Sept. 21, 2015 Pennsylvania State University (Penn State) news release by Matt Swayne (also on EurekAlert) puts a different spin on art/science (Note: Links have been removed),

Museum curators planning to develop virtual exhibits online should choose communication and navigation technologies that match the experience they want to offer their visitors, according to a team of researchers.

“When curators think about creating a real-world exhibit, they are thinking about what the theme is and what they want their visitors to get out of the exhibit,” said S. Shyam Sundar, Distinguished Professor of Communications and co-director of the Media Effects Research Laboratory. “What this study suggests is that, just like curators need to be coherent in the content of the exhibit, they need to be conscious of the tools that they employ in their virtual museums.” [emphasis mine]

For some reason that phrase “need to be conscious of the tools that they employ” reminds of Marshall McLuhan and his dictum “the medium is the message.” Here’s more about study from the news release,

Many museum curators hope to create an authentic experience in their online museums by using technology to mimic aspects of the social, personal and physical aspects of a real-world museum experience. However, a more-is-better approach to technology may actually hinder that authentic experience, the researchers suggest.

In a study, visitors to an online virtual art museum found that technology tools used to communicate about and navigate through the exhibits were considered helpful when they were available separately, but less so when they were offered together. The researchers tested customization tools that helped the participants create their own art gallery, live-chat technology to facilitate communication with other visitors and 3-D tool navigation tools that some participants used to explore the museum.

The participants’ experiences often depended on what tools and what combinations of tools they used, according to the researchers, who released their findings in a recent issue of the International Journal of Human-Computer Interaction.

The news release goes on to provide some examples of when technologies do not mesh together for a good experience,

“When live chat and customization are offered together, for example, the combination of tools may be perceived to have increased usability, but it turns out using either customization or live chat separately was greater than either both functions together, or neither of the functions,” said Sundar. “We saw similar results not just with perceived usability, but also with sense of control and agency.”

The live chatting tool gave participants a feeling of social presence in the museum, but when live chatting was used in conjunction with the 3D navigation tool, the visitor had less of a sense of control, said Sundar, who worked with Eun Go, assistant professor of broadcasting and journalism, Western Illinois University; Hyang-Sook Kim, assistant professor of mass communication and media communication studies, Towson University and Bo Zhang, doctoral candidate in mass communications, Penn State.

Similarly, participants indicated the live chatting function lessened the realistic experience of the 3D tool, according to the researchers, who suggested that chatting may increase the user’s cognitive burden as they try to navigate through the site.

Each of these tools carries unique meaning for users, Sundar said. While customization provides an individualized experience, live-chatting signals a social experience of the site.

“Our data also suggest that expert users prefer tools that offer more agency or control to users whereas novices appreciate a variety of tools on the interface,” he added.

Users may react to these tools on other online platforms, not just during visits to online museums, Sundar said.

“We might be able to apply this research on tools you might add to news sites, for example, or it could be used to improve educational sites and long-distance learning,” he added. “You just have to be careful about how you deploy the tools because more is not always better.”

The researchers recruited 126 participants for the study. The subjects were assigned one of eight different website variations that tested their reactions to customization, live chat, 3D navigation and combinations of those tools during their visit to a virtual version of the Museum of Modern Art. The museum’s artworks were made available through the Google Art Project.

Here’s a link to and a citation for the paper,

Communicating Art, Virtually! Psychological Effects of Technological Affordances in a Virtual Museum by S. Shyam Sundar, Eun Goc, Hyang-Sook Kim, & Bo Zhang. International Journal of Human-Computer Interaction
Volume 31, Issue 6, 2015 pages 385-401 DOI: 10.1080/10447318.2015.1033912 Accepted author version posted online: 15 Apr 2015

This paper is behind a paywall.

Acoustofluidics and lab-on-a-chip for asthma and tuberculosis diagnostics

This is my first exposure to acoustofluidics (although it’s been around for a few years) and it concerns lab-on-a-chip diagnostics for asthma and tuberculosis. From an Aug. 3, 2015 news item on Azonano,

A device to mix liquids utilizing ultrasonics is the first and most difficult component in a miniaturized system for low-cost analysis of sputum from patients with pulmonary diseases such as tuberculosis and asthma.

The device, developed by engineers at Penn State in collaboration with researchers at the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health, and the Washington University School of Medicine, will benefit patients in the U.S., where 12 percent of the population, or around 19 million people, have asthma, and in undeveloped regions where TB is still a widespread and often deadly contagion.

“To develop more accurate diagnosis and treatment approaches for patients with pulmonary diseases, we have to analyze sample cells directly from the lungs rather than by drawing blood,” said Tony Jun Huang, professor of engineering science and mechanics at Penn State and the inventor, with his group, of this and other acoustofluidic devices based on ultrasonic waves. “For instance, different drugs are used to treat different types of asthma patients. If you know what a person’s immunophenotype is, you can provide personalized medicine for their particular disease.

A July 29, 2015 Pennsylvania State University news release, which originated the news item, describes the disadvantages of the current sputum analyses techniques and explains how this new technique in an improvement,

There are several issues with the current standard method for sputum analysis. The first is that human specimens can be contagious, and sputum analysis requires handling of specimens in several discrete machines. With a lab on a chip device, all biospecimens are safely contained in a single disposable component.

Another issue is the sample size required for analysis in the current system, which is often larger than a person can easily produce. The acoustofluidic sputum liquefier created by Huang’s group requires 100 times less sample while still providing accuracy equivalent to the standard system.

A further issue is that current systems are difficult to use and require trained operators. With the lab on a chip system, a nurse can operate the device with a touch of a few buttons and get a read out, or the patient could even operate the device at home. In addition, the disposable portion of the device should cost less than a dollar to manufacture.

Po-Hsun Huang, a graduate student in the Huang group and the first author on the recent paper describing the device in the Royal Society of Chemistry journal Lab on a Chip, said “This will offer quick analysis of samples without having to send them out to a centralized lab. While I have been working on the liquefaction component of the device, my lab mates are working on the flow cytometry analysis component, which should be ready soon. This is the first on-chip sputum liquefier anyone has developed.”

Stewart J. Levine, a Senior Investigator and Chief of the Laboratory of Asthma and Lung Inflammation in the Division of Intramural Research at NHLBI, said “This on-chip sputum liquefier is a significant advance regarding our goal of developing a point-of-care diagnostic device that will determine the type of inflammation present in the lungs of asthmatics. This will allow health care providers to individualize asthma treatments for each patient and advance the goal of bringing precision medicine into clinical practice.”

Here’s a link to and a citation for the paper,

An acoustofluidic sputum liquefier by Po-Hsun Huang, Liqiang Ren, Nitesh Nama, Sixing Li, Peng Li, Xianglan Yao, Rosemarie A. Cuento, Cheng-Hsin Wei, Yuchao Chen, Yuliang Xie, Ahmad Ahsan Nawaz, Yael G. Alevy, Michael J. Holtzman, J. Philip McCoy, Stewart J. Levine, and  Tony Jun Huang. Lab Chip, 2015,15, 3125-3131 DOI: 10.1039/C5LC00539F

First published online 17 Jun 2015

This is an open access paper but you do need to register for a free (British) Royal Society of Chemistry publishing personal account.

Wacky oxide. biological synchronicity, and human brainlike computing

Research out of Pennsylvania State University (Penn State, US) has uncovered another approach  to creating artificial brains (more about the other approaches later in this post), from a May 14, 2014 news item on Science Daily,

Current computing is based on binary logic — zeroes and ones — also called Boolean computing. A new type of computing architecture that stores information in the frequencies and phases of periodic signals could work more like the human brain to do computing using a fraction of the energy of today’s computers.

A May 14, 2014 Pennsylvania State University news release, which originated the news item, describes the research in more detail,

Vanadium dioxide (VO2) is called a “wacky oxide” because it transitions from a conducting metal to an insulating semiconductor and vice versa with the addition of a small amount of heat or electrical current. A device created by electrical engineers at Penn State uses a thin film of VO2 on a titanium dioxide substrate to create an oscillating switch. Using a standard electrical engineering trick, Nikhil Shukla, a Ph.D. student in the group of Professor Suman Datta and co-advised by Professor Roman Engel-Herbert at Penn State, added a series resistor to the oxide device to stabilize their oscillations over billions of cycles. When Shukla added a second similar oscillating system, he discovered that over time the two devices would begin to oscillate in unison. This coupled system could provide the basis for non-Boolean computing. The results are reported in the May 14 [2014] online issue of Nature Publishing Group’s Scientific Reports.

“It’s called a small-world network,” explained Shukla. “You see it in lots of biological systems, such as certain species of fireflies. The males will flash randomly, but then for some unknown reason the flashes synchronize over time.” The brain is also a small-world network of closely clustered nodes that evolved for more efficient information processing.

“Biological synchronization is everywhere,” added Datta, professor of electrical engineering at Penn State and formerly a Principal Engineer in the Advanced Transistor and Nanotechnology Group at Intel Corporation. “We wanted to use it for a different kind of computing called associative processing, which is an analog rather than digital way to compute.” An array of oscillators can store patterns, for instance, the color of someone’s hair, their height and skin texture. If a second area of oscillators has the same pattern, they will begin to synchronize, and the degree of match can be read out. “They are doing this sort of thing already digitally, but it consumes tons of energy and lots of transistors,” Datta said. Datta is collaborating with co-author and Professor of Computer Science and Engineering, Vijay Narayanan, in exploring the use of these coupled oscillations in solving visual recognition problems more efficiently than existing embedded vision processors as part of a National Science Foundation Expedition in Computing program.

Shukla and Datta called on the expertise of Cornell University materials scientist Darrell Schlom to make the VO2 thin film, which has extremely high quality similar to single crystal silicon. Georgia Tech computer engineer Arijit Raychowdhury and graduate student Abhinav Parihar mathematically simulated the nonlinear dynamics of coupled phase transitions in the VO2 devices. Parihar created a short video* simulation of the transitions, which occur at a rate close to a million times per second, to show the way the oscillations synchronize. Penn State professor of materials science and engineering Venkatraman Gopalan used the Advanced Photon Source at Argonne National laboratory to visually characterize the structural changes occurring in the oxide thin film in the midst of the oscillations.

Datta believes it will take seven to ten years to scale up from their current network of two-three coupled oscillators to the 100 million or so closely packed oscillators required to make a neuromorphic computer chip. One of the benefits of the novel device is that it will use only about one percent of the energy of digital computing, allowing for new ways to design computers. Much work remains to determine if VO2 can be integrated into current silicon wafer technology. “It’s a fundamental building block for a different computing paradigm that is analog rather than digital,” Shukla concluded.

There are two papers being published about this work,

Synchronizing a single-electron shuttle to an external drive by Michael J Moeckel, Darren R Southworth, Eva M Weig, and Florian Marquardt. New J. Phys. 16 043009 doi:10.1088/1367-2630/16/4/043009

Synchronized charge oscillations in correlated electron systems by Nikhil Shukla, Abhinav Parihar, Eugene Freeman, Hanjong Paik, Greg Stone, Vijaykrishnan Narayanan, Haidan Wen, Zhonghou Cai, Venkatraman Gopalan, Roman Engel-Herbert, Darrell G. Schlom, Arijit Raychowdhury & Suman Datta. Scientific Reports 4, Article number: 4964 doi:10.1038/srep04964 Published 14 May 2014

Both articles are open access.

Finally, the researchers have provided a video animation illustrating their vanadium dioxide switches in action,

As noted earlier, there are other approaches to creating an artificial brain, i.e., neuromorphic engineering. My April 7, 2014 posting is the most recent synopsis posted here; it includes excerpts from a Nanowerk Spotlight article overview along with a mention of the ‘brain jelly’ approach and a discussion of my somewhat extensive coverage of memristors and a mention of work on nanoionic devices. There is also a published roadmap to neuromorphic engineering featuring both analog and digital devices, mentioned in my April 18, 2014 posting.

Nano jobs, bits, and bobs

There’s a postdoctoral position at Penn State Center for Nanoscale Science (from the NISE [Nanoscale Informal Science Education] Net October newsletter),

Nano Employment Opportunity: Postdoctoral Position in Education and Outreach with Penn State MRSEC

The Penn State Center for Nanoscale Science, a NSF-supported Materials Research Science and Engineering Center (MRSEC), has a postdoctoral position available in education and outreach. The successful candidate will join a team developing and presenting education and outreach programs materials including nanoscience curriculum for K-12 students and teachers among other tasks. Interested applicants should go to the Penn State job opportunity site and scroll down to the Postdoctoral Position – Center for Nanoscale Science (MRSEC Center) listing for more details and application instructions.

The newsletter also features its monthly nano haiku,

Teeny-tiny stuff,
you act so different now.
Wish you were still big.

by Leigha Horton of the Science Museum of Minnesota.

Thanks to someone on Twitter (sorry, I don’t remember who) I found  Nature journalist Geoff Brumfiel’s interview (published Oct. 7, 2010) with one of the winners (Andre Geim) of the 2010 Nobel Prize for Physics. Given my interest in intellectual property, here’s Geim’s response to a question about patents,

You haven’t yet patented graphene. Why is that?

We considered patenting; we prepared a patent and it was nearly filed. Then I had an interaction with a big, multinational electronics company. I approached a guy at a conference and said, “We’ve got this patent coming up, would you be interested in sponsoring it over the years?” It’s quite expensive to keep a patent alive for 20 years. The guy told me, “We are looking at graphene, and it might have a future in the long term. If after ten years we find it’s really as good as it promises, we will put a hundred patent lawyers on it to write a hundred patents a day, and you will spend the rest of your life, and the gross domestic product of your little island, suing us.” That’s a direct quote.

I considered this arrogant comment, and I realized how useful it was. There was no point in patenting graphene at that stage. You need to be specific: you need to have a specific application and an industrial partner. Unfortunately, in many countries, including this one, people think that applying for a patent is an achievement. In my case it would have been a waste of taxpayers’ money.

This is a very engaging and funny (particularly Geim’s response to the final question: “Finally, are you one of those Nobel prizewinners who is going to go crazy now that you’ve won?” of the interview.