Posts tagged results
CU study: Graphene membranes may lead to enhanced natural gas production, less CO2 pollution
Oct 8th
Engineering faculty and students at the University of Colorado Boulder have produced the first experimental results showing that atomically thin graphene membranes with tiny pores can effectively and efficiently separate gas molecules through size-selective sieving.
The findings are a significant step toward the realization of more energy-efficient membranes for natural gas production and for reducing carbon dioxide emissions from power plant exhaust pipes.
Mechanical engineering professors Scott Bunch and John Pellegrino co-authored a paper in Nature Nanotechnology with graduate students Steven Koenig and Luda Wang detailing the experiments. The paper was published Oct. 7 in the journal’s online edition.
The research team introduced nanoscale pores into graphene sheets through ultraviolet light-induced oxidative “etching,” and then measured the permeability of various gases across the porous graphene membranes. Experiments were done with a range of gases including hydrogen, carbon dioxide, argon, nitrogen, methane and sulphur hexaflouride — which range in size from 0.29 to 0.49 nanometers — to demonstrate the potential for separation based on molecular size. One nanometer is one billionth of a meter.
“These atomically thin, porous graphene membranes represent a new class of ideal molecular sieves, where gas transport occurs through pores which have a thickness and diameter on the atomic scale,” said Bunch.
Graphene, a single layer of graphite, represents the first truly two-dimensional atomic crystal. It consists of a single layer of carbon atoms chemically bonded in a hexagonal “chicken wire” lattice — a unique atomic structure that gives it remarkable electrical, mechanical and thermal properties.
“The mechanical properties of this wonder material fascinate our group the most,” Bunch said. “It is the thinnest and strongest material in the world, as well as being impermeable to all standard gases.”
Those characteristics make graphene an ideal material for creating a separation membrane because it is durable and yet doesn’t require a lot of energy to push molecules through it, he said.
Other technical challenges will need to be overcome before the technology can be fully realized. For example, creating large enough sheets of graphene to perform separations on an industrial scale, and developing a process for producing precisely defined nanopores of the required sizes are areas that need further development. The CU-Boulder experiments were done on a relatively small scale.
The importance of graphene in the scientific world was illustrated by the 2010 Nobel Prize in physics that honored two scientists at Manchester University in England, Andre K. Geim and Konstantin Novoselov, for producing, isolating, identifying and characterizing graphene. Scientists see a myriad of potential for graphene as research progresses, from making new and better display screens and electric circuits to producing tiny biomedical devices.
The research was sponsored by the National Science Foundation; the Membrane Science, Engineering and Technology Center at CU-Boulder; and the DARPA Center on Nanoscale Science and Technology for Integrated Micro/Nano Electromechanical Transducers at CU-Boulder.
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CU -R U an explanation “foe” or “fiend” when shopping?
Sep 19th
Consumers differ in desire for explanation,
says new CU-Brown University study
says new CU-Brown University study
The depth of explanation about novel products influences consumer preferences and willingness to pay, according to a study led by the University of Colorado Boulder and Brown University.
When it comes to descriptions about the functions of new and unusual goods — such as a self-watering plant system, special gloves for touchscreens or an eraser for wall scratches — some people prefer minimal details. Dubbed “explanation foes” in the study, they gain a strong sense of understanding and desire for products through shallow explanations.
In contrast, other people — dubbed “explanation fiends” in the study — derive desire for products from deep and detailed explanations.
“There are these two different types of consumers,” said lead author Phil Fernbach, assistant professor of marketing at CU-Boulder’s Leeds School of Business. “On these two sides, consumers differ in the amount of detail that makes them feel like they understand and — because of that feeling of understanding — the amount of detail that will make them prefer a 
product.”
A paper on the subject was published online today in the Journal of Consumer Research.
Researchers say the study results can help consumers make better decisions.
“We’re not making a value judgment on whether it’s better to be an ‘explanation foe’ or ‘fiend,’ ” said Fernbach. “You don’t have to want to know how stuff works, but make sure that your intuition about whether you understand a product is based on objective information and not just a feeling.”
In one part of the study, participants were given varying explanations of a new tinted food wrapper product. “Explanation foes” highly rated their understanding and preference for the item when they read a simple description of how its “white coloring protects food from light that causes it to spoil, thereby keeping food fresh for longer.”
“Explanation fiends” highly rated their understanding and preference for the food wrapper when they read a more detailed description of how “atoms in the tinting agent oscillate when hit by light waves causing them to absorb the energy and reflect it back rather than reaching food, where it would break the bonds holding amino acids together, thereby keeping food fresh for longer.”
The study also found that “explanation foes,” who are more common, tend to have an inflated sense of understanding about novel products. Their heightened perception disappears and their willingness to pay decreases when they attempt to explain how a product works.
Conversely, “explanation fiends” tend to have a more conservative sense of understanding about novel products. For them, attempting to explain how a product works does not have a negative effect on their sense of understanding and their opinion of the product stays the same or increases, according to the study.
Attitudes toward explanation were predicted by a cognitive reflection test that measures how much people naturally engage in deliberative thinking. Each test question elicits an intuitive but incorrect answer and participants who impulsively respond tend to err. These participants are the “explanation foes” who prefer less explanation.
In contrast, those who inhibit their initial responses to the cognitive reflection test and think more deeply tend to correctly answer. These participants are the “explanation fiends” who prefer more in-depth descriptions.
While the study can help consumers with better decision-making, it also yields advice for marketers.
“Marketers should target these different consumer groups with different types of explanations,” said Steven Sloman, a study co-author and professor of cognitive, linguistic and psychological sciences at Brown University.
Robert St. Louis and Julia Shube also were co-authors of the study. They were undergraduate students at Brown during the research. Unilever, a consumer goods company, supported the study.
Wrap your mind around this! photo origami CU Boulder
Aug 27th
CU-Boulder ‘photo origami’ proposal
wins $2 million NSF grant
wins $2 million NSF grant
The art of origami has inspired children and artists all over the world because of the amazing objects that can be created by folding a simple piece of paper.
Now an engineering research team at the University of Colorado Boulder has won a $2 million grant from the National Science Foundation to develop a light-controlled approach for “self-assembly” mechanisms in advanced devices based on the same principles.
Known as “photo origami,” the idea is supported by NSF’s Emerging Frontiers in Research and Innovation program, which supports interdisciplinary teams working on rapidly advancing frontiers of fundamental engineering research.
CU-Boulder associate professor of mechanical engineering Jerry Qi will lead the team developing the photo origami technique. Collaborators will include CU faculty Robert McLeod of electrical engineering, Kurt Maute of aerospace engineering sciences and Elisabeth “Beth” Stade of mathematics, along with Patrick Mather of Syracuse University.
The ability to transform a flat polymer sheet into a sophisticated, mechanically robust 3-D structure will enable new approaches to manufacturing and design of devices from the microscopic to centimeter scales, according to the team. Examples include using extremely low-weight, high-strength materials to create micro-electromechanical systems with complicated 3-D architectures that can be used for microscopic sensors such as antennas or microphones, and miniature robotic devices for environmental monitoring.
Present barriers to the development of folding and unfolding mechanisms stem from the lack of understanding of scaling laws that allow researchers to generalize results obtained at various size scales, the inability to easily cause matter to “reorient” itself to achieve the desired folding patterns, and challenges in automated, sequential folding.
To overcome these challenges, the CU team will make use of recent fundamental advances in the control of polymer architecture through light-triggered chemical reactions.
“One has to accurately control how much deformation a material should have in order to obtain a precise folding angle and to determine where to fold or stop folding in order to avoid interference in the folding path and form the desired structure,” said McLeod, who will use the interaction of light with material deformation to develop optical waveguide transistors.
In this new form of logic circuit, light triggers the deformation of a soft polymer, which in turn switches the light on or off. In this way, the optical waveguide transistor will enable a structure to be pre-programmed with a folding pattern through a sequential set of switching events controlled by the shape of an origami sheet.
In recent years, CU researchers and their collaborators have made significant progress in using light to control and alter the structure of a polymer. They are able to both bend and stiffen polymer structures and to develop new, soft, shape-memory composite materials through photo-initiation techniques. Shape-memory composites are “smart” materials that have the ability to return from a temporary, deformed shape to their original shape when induced by a trigger.
In addition, the team will work with the local school district to provide research and educational opportunities for K-12 students and teachers.
