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August 14th, 2012

Other materials science stories that may be of interest

Published on August 14th, 2012 | By: pwray@ceramics.org

Lots of interesting work happening out there:

Making “renewable” viable: Drexel engineers develop new technology for grid-level electrical energy storage

A team of researchers from Drexel University’s College of Engineering has developed a new method for quickly and efficiently storing large amounts of electrical energy. The researchers are putting forward a plan to integrate into the grid an electrochemical storage system that combines principles behind the flow batteries and supercapacitors. The team’s research yielded a novel solution that combines the strengths of batteries and supercapacitors while also negating the scalability problem. The “electrochemical flow capacitor” consists of an electrochemical cell connected to two external electrolyte reservoirs—a design similar to existing redox flow batteries that are used in electrical vehicles. This technology is unique because it uses small carbon particles suspended in the electrolyte liquid to create a slurry of particles that can carry an electric charge. Uncharged slurry is pumped from its tanks through a flow cell, where energy stored in the cell is then transferred to the carbon particles. The charged slurry can then be stored in reservoirs until the energy is needed, at which time the entire process is reversed in order to discharge the EFC. The main advantage of the EFC is that its design allows it to be constructed on a scale large enough to store large amounts of energy, while also allowing for rapid disbursal of the energy when the demand dictates it. “By using a slurry of carbon particles as the active material of supercapacitors, we are able to adopt the system architecture from redox flow batteries and address issues of cost and scalability,” says Yury Gogotsi, director of the A.J. Drexel Nanotechnology Institute and the lead researcher on the project. “A liquid storage system, the capacity of which is limited only by the tank size, can be cost-effective and scalable. …However, we will need to increase the energy density per unit of slurry volume by an order of magnitude, and achieve it using very inexpensive carbon and salt solutions to make the technology practical.”

Application of compressed sensing to the simulation of atomic systems

(PNAS) Compressed sensing is a method that allows a significant reduction in the number of samples required for accurate measurements in many applications in experimental sciences and engineering. In this work, we show that compressed sensing can also be used to speed up numerical simulations. We apply compressed sensing to extract information from the real-time simulation of atomic and molecular systems, including electronic and nuclear dynamics. We find that, compared to the standard discrete Fourier transform approach, for the calculation of vibrational and optical spectra the total propagation time, and hence the computational cost, can be reduced by approximately a factor of five.

Composite polymer nanofibers developed by Penn scientists next chapter in orthopedic biomaterials

Bioengineered replacements for tendons, ligaments, the meniscus of the knee, and other tissues require re-creation of the exquisite architecture of these tissues in three dimensions. These fibrous, collagen-based tissues located throughout the body have an ordered structure that gives them their robust ability to bear extreme mechanical loading. One popular approach has involved the use of scaffolds made from nano-sized fibers, which can guide tissue to grow in an organized way. Unfortunately, the fibers’ widespread application in orthopaedics has been slowed because cells do not readily colonize the scaffolds if fibers are too tightly packed. Researchers at University of Pennsylvania have developed and validated a new technology in which composite nanofibrous scaffolds provide a loose enough structure for cells to colonize without impediment, but still can instruct cells how to lay down new tissue. Via electrospinning, the team made composites containing two distinct fiber types: a slow-degrading polymer and a water-soluble polymer that can be selectively removed to increase or decrease the spacing between fibers. Increasing the proportion of the dissolving fibers enhanced the ability of host cells to colonize the nanofiber mesh and eventually migrate to achieve a uniform distribution and form a truly three-dimensional tissue. The team is currently testing these novel materials in a large animal model of meniscus repair and for other orthopedic applications.

Spray-on skin speeds healing of venous leg ulcers

(Gizmag) A solution containing skin cells and proteins has been shown to speed the healing of venous leg ulcers. While the ulcers can be quite resistant to treatment, a team of scientists is now reporting success in using a sort of “spray-on skin” to heal them. Developed by Texas-based Healthpoint Biotherapeutics, the spray-on solution consists of neonatal keratinocytes and fibroblasts (skin cells), which are suspended in a liquid made up of various proteins associated with blood clotting. It was tested using a group of 228 patients afflicted with the ulcers, all of whom were also treated with compression bandages. It was found that when compared that control group, patients receiving the optimum dosage experienced a 16 percent greater reduction in wound area after seven days. After 12 weeks, they were 52 percent more likely to have achieved wound closure. Not only were the ulcers on patients receiving the optimum dosage more likely to heal, but they also healed quicker – in the control group, ulcers that did heal took an average of 21 days longer to do so. It has been suggested that the spray-on solution may also be useful in treating other types of chronic wounds, such as ischemic and diabetic foot ulcers.

NIST focuses on testing standards to support lab-on-a-chip commercialization

(Tech Beat) A recent paper from the National Institute of Standards and Technology argues that before lab-on-a-chip technology can be fully commercialized, testing standards need to be developed and implemented. Standardized testing and measurement methods, paper author Samuel Stavis writes, will enable MEMS LOC manufacturers at all stages of production-from processing of raw materials to final rollout of products-to accurately determine important physical characteristics of LOC devices such as dimensions, electrical surface properties, and fluid flow rates and temperatures. To make his case for testing standards, Stavis focuses on autofluorescence. Stavis states that multiple factors must be considered in the development of a testing standard for autofluorescence, including: the materials used in the device, the measurement methods used to test the device and how the measurements are interpreted. “All of these factors must be rigorously controlled for, or appropriately excluded from, a meaningful measurement of autofluorescence,” Stavis writes.

Here comes the sun: NASA picks solar array system development proposals

NASA’s Space Technology Program has selected Deployable Space Systems of Goleta, Calif. and ATK Space Systems Inc., of Commerce, Calif., for contract negotiation to develop advanced solar array systems. High-power solar electric propulsion, where the power is generated with advanced solar array systems, is a key capability required for extending human presence throughout the solar system. The selected proposals offer innovative approaches to the development of next-generation, large-scale solar arrays and associated deployment mechanisms. These advanced solar arrays will drastically reduce weight and stowed volume when compared to current systems. They also will significantly improve efficiency and functionality of future systems that will produce hundreds of kilowatts of power. These advanced solar arrays could be used in future NASA human exploration and science missions, communications satellites and a majority of other future spacecraft applications.

Fuel cell electric vehicles make rapid progress in range, durability (final report, pdf)

The Department of Energy’s National Renewable Energy Laboratory recently completed a seven-year project to demonstrate and evaluate hydrogen fuel cell electric vehicles and hydrogen fueling infrastructure in real-world settings. The National Fuel Cell Electric Vehicle Learning Demonstration Final Report shows progress in extending vehicle driving ranges and increasing fuel cell durability and discusses NREL’s key findings from the demonstration project. This effort, funded by DOE’s Office of Energy Efficiency and Renewable Energy, supports the Department’s broader strategy to advance U.S. leadership in hydrogen and fuel cell technological innovation and help the industry bring these technologies into the marketplace at lower cost.

UToronto researchers invent new tissue engineering tool; claims growth of large batch of functional tissue possible

Researchers from the University of Toronto have invented a new device that may allow for the uniform, large-scale engineering of tissue. Scientists manipulate biomaterials into the microdevice through several channels. The biomaterials are then mixed, causing a chemical reaction that forms a “mosaic hydrogel”—a sheet-like substance compatible with the growth of cells into living tissues, into which different types of cells can be seeded in very precise and controlled placements. Unique to this new approach to tissue engineering, however, and unlike more typical methods (for instance, scaffolding), cells planted onto the mosaic hydrogel sheets are precisely incorporated into the mosaic hydrogel sheet just at the time it’s being created, generating the perfect conditions for cells to grow. The placement of the cells is so precise can precisely mimic the natural placement of cells in living tissues. And, by collecting these sheets around a drum, the machine is able to collect layers of cells in thicknesses made to measure: in essence, three dimensional, functional tissues.

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