'Meating' a solution: Research finds that LED lights extend meat shelf life, save retailers money

Kyle Steele, recent master's graduate in animal sciences and industry, Silver Lake, Kan., found that using light-emitting diode, or LED, lights in refrigeration units both saves energy for meat retailers and extends the shelf life of some beef products.

"By using LED lighting in meat retail display cases, Kansas retailers can save money by lowering the operational costs of refrigerated cases and extending the color shelf life of fresh meat products," Steele said. "Additionally, by extending the color shelf life, retailers have a greater opportunity to sell the product at full price, and the state of Kansas can gain tax revenue from the full retail price rather than a discounted price."

Steele compared the use of LED lights and fluorescent lights in meat refrigeration units because many meat retailers currently use fluorescent lights. He worked with Elizabeth Boyle and Melvin Hunt, both professors of animal sciences and industry, as well as with Melissa Weber, recent doctoral graduate in animal sciences and industry, Collinwood, Tenn.

During refrigerated display, the color of fresh meat changes because of its natural chemistry and exposure to oxygen. Because color is a large factor that influences customers in purchasing meat, some consumers discriminate against discolored meat. These discolored meat products must either be discounted or discarded, which has been estimated to cost the meat industry up to a billion dollars each year, Steele said.

For his research, Steele looked at five different meat products: pork loin chops, beef loin steaks, ground beef, ground turkey and beef inside round steaks. Steele looked at several aspects of these meat products and their refrigeration units:

* Discoloration: The researchers brought in trained color panelists to score meat color changes over time while displayed under both lighting types.

* Rancidity: The researchers measured the rancidity of the meat products stored under both types of light. Light affects the oxidation of fat in meat, which can cause rancidity and a change in taste.

* Operating efficiency: The researchers studied operating efficiency of the two types of lights by measuring how many times a refrigeration unit had to cycle to keep the meat cool and how many running hours that cycle lasted.

The researchers found that LED lights scored positively in nearly all areas. Most significantly, LED lights helped reduce operating costs and prolonged the shelf life for most of the meat products.

"Most meat products displayed under LED lighting had colder internal product temperatures, which helps extend product shelf life," Steele said. "Beef loin steaks and inside round steaks that were stored under LED lights can have up to one day longer shelf life."

Among operational costs, LED lights had fewer cycles per running hour, meaning they were a more efficient and cost-saving light source than fluorescent lights.

Steele will give a research presentation titled "Shelf life of five meat products displayed under light emitting diode or fluorescent lighting" at the Capitol Graduate Research Summit in Topeka in February.

Provided by Kansas State University (news : web)

Graphene lights up with new possibilities: Two-step technique makes graphene suitable for organic chemistry

 The future brightened for organic chemistry when researchers at Rice University found a highly controllable way to attach organic molecules to pristine graphene, making the miracle material suitable for a range of new applications.

The Rice lab of chemist James Tour, building upon a set of previous finds in the manipulation of graphene, discovered a two-step method that turned what was a single-atom-thick sheet of carbon into a superlattice for use in organic chemistry. The work could lead to advances in graphene-based chemical sensors, thermoelectric devices and metamaterials.

The work appears in the online journal Nature Communications.

Graphene alone is inert to many organic reactions and, as a semimetal, has no band gap; this limits its usefulness in electronics. But the project led by the Tour Lab's Zhengzong Sun and Rice graduate Cary Pint, now a researcher at Intel, demonstrated that graphene, the strongest material there is because of the robust nature of carbon-carbon bonds, can be made suitable for novel types of chemistry.

Until now there was no way to attach molecules to the basal plane of a sheet of graphene, said Tour, Rice's T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science. "They would mostly go to the edges, not the interior," he said. "But with this two-step technique, we can hydrogenate graphene to make a particular pattern and then attach molecules to where those hydrogens were.

"This is useful to make, for example, chemical sensors in which you want peptides, DNA nucleotides or saccharides projected upward in discrete places along a device. The reactivity at those sites is very fast relative to placing molecules just at the edges. Now we get to choose where they go."

The first step in the process involved creating a lithographic pattern to induce the attachment of hydrogen atoms to specific domains of graphene's honeycomb matrix; this restructure turned it into a two-dimensional, semiconducting superlattice called graphane. The hydrogen atoms were generated by a hot filament using an approach developed by Robert Hauge, a distinguished faculty fellow in chemistry at Rice and co-author of the paper.

The lab showed its ability to dot graphene with finely wrought graphane islands when it dropped microscopic text and an image of Rice's classic Owl mascot, about three times the width of a human hair, onto a tiny sheet and then spin-coated it with a fluorophore. Graphene naturally quenches fluorescent molecules, but graphane does not, so the Owl literally lit up when viewed with a new technique called fluorescence quenching microscopy (FQM).

FQM allowed the researchers to see patterns with a resolution as small as one micron, the limit of conventional lithography available to them. Finer patterning is possible with the right equipment, they reasoned.

In the next step, the lab exposed the material to diazonium salts that spontaneously attacked the islands' carbon-hydrogen bonds. The salts had the interesting effect of eliminating the hydrogen atoms, leaving a structure of carbon-carbon sp3 bonds that are more amenable to further functionalization with other organics.

"What we do with this paper is go from the graphene-graphane superlattice to a hybrid, a more complicated superlattice," said Sun, who recently earned his doctorate at Rice. "We want to make functional changes to materials where we can control the position, the bond types, the functional groups and the concentrations.

"In the future -- and it might be years -- you should be able to make a device with one kind of functional growth in one area and another functional growth in another area. They will work differently but still be part of one compact, cheap device," he said. "In the beginning, there was very little organic chemistry you could do with graphene. Now we can do almost all of it. This opens up a lot of possibilities."

The paper's co-authors are graduate students Daniela Marcano, Gedeng Ruan and Zheng Yan, former graduate student Jun Yao, postdoctoral researcher Yu Zhu and visiting student Chenguang Zhang, all of Rice.

The work was supported by the Air Force Office of Scientific Research, Sandia National Laboratory, the Nanoscale Science and Engineering Initiative of the National Science Foundation and the Office of Naval Research MURI graphene program.

Story Source:

The above story is reprinted from materials provided by Rice University.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

Zhengzong Sun, Cary L. Pint, Daniela C. Marcano, Chenguang Zhang, Jun Yao, Gedeng Ruan, Zheng Yan, Yu Zhu, Robert H. Hauge, James M. Tour. Towards hybrid superlattices in graphene. Nature Communications, 2011; 2: 559 DOI: 10.1038/ncomms1577

Lights and flat-panel displays: Researchers 'brighten' the future of organic light-emitting diode technology

 Chlorine is an abundant and readily available halogen gas commonly associated with the sanitation of swimming pools and drinking water. Could a one-atom thick sheet of this element revolutionize the next generation of flat-panel displays and lighting technology?

In the case of Organic Light-Emitting Diode (OLED) devices, it most certainly can. Primary researchers Michael G. Helander (PhD Candidate and Vanier Canada Graduate Scholar), Zhibin Wang (PhD Candidate), and led by Professor Zheng-Hong Lu of the Department of Materials Science & Engineering at the University of Toronto, have found a simple method of using chlorine to drastically reduce traditional OLED device complexity and dramatically improve its efficiency all at the same time. By engineering a one-atom thick sheet of chlorine onto the surface of an existing industry-standard electrode material (indium tin oxide, ITO) found in today's flat-panel displays, these researchers have created a medium that allows for efficient electrical transport while eliminating the need for several costly layers found in traditional OLED devices.

"It turns out that it's remarkably easy to engineer this one-atom thick layer of chlorine onto the surface of ITO," says Helander. "We developed a UV light assisted process to achieve chlorination, which negates the need for chlorine gas, making the entire procedure safe and reliable."

The team tested their green-emitting "Cl-OLED" against a conventional OLED and found that the efficiency was more than doubled at very high brightness. "OLEDs are known for their high-efficiency," says Helander. "However, the challenge in conventional OLEDs is that as you increase the brightness, the efficiency drops off rapidly."

Using their chlorinated ITO, this team of advanced materials researchers found that they were able to prevent this drop off and achieve a record efficiency of 50% at 10,000 cd/m2 (a standard florescent light has a brightness of approximately 8,000 cd/m2), which is at least two times more efficient than the conventional OLED.

"Our Cl-ITO eliminates the need for several stacked layers found in traditional OLEDs, reducing the number of manufacturing steps and equipment, which ultimately cuts down on the costs associated with setting up a production line," says Professor Zheng-Hong Lu.

"This effectively lowers barriers for mass production and thereby accelerates the adoption of OLED devices into mainstream flat-panel displays and other lighting technologies."

The results of this work are published online in the journal Science on April 14, 2011.

Story Source:

The above story is reprinted (with editorial adaptations) from materials provided by University of Toronto Faculty of Applied Science and Engineering.

Journal Reference:

M. G. Helander, Z. B. Wang, J. Qiu, M. T. Greiner, D. P. Puzzo, Z. W. Liu, and Z. H. Lu. Chlorinated Indium Tin Oxide Electrodes with High Work Function for Organic Device Compatibility. Science, 14 April 2011 DOI: 10.1126/science.1202992